Optical imaging assembly, optical imaging module and device

Abstract

The present application relates to an optical imaging assembly, an optical imaging module, a levitation display device and a multi-layer display device for levitation display. The optical imaging assembly comprises: a plurality of retroreflective screens, the plurality of retroreflective screens are arranged at intervals in a first direction; and a polarization beam splitter configured to reflect first polarized light and transmit second polarized light, the first polarized light and the second polarized light having different polarization states; wherein the optical imaging assembly is configured to receive or emit image light from an object plane via the intervals between the plurality of retroreflective screens, and to cause a light beam from a point on the object plane to converge on a first image plane in at least one of the first direction and a second direction, the first direction and the second direction being orthogonal to a principal optical axis of the optical imaging assembly, respectively.

Description

Technical Field

[0001] The embodiments described herein generally relate to light field three-dimensional display technology, and more specifically to an optical imaging component, an optical imaging module, a suspended display device, and a multi-layer display device. Background Technology

[0002] Among the many display technologies, aerial levitation display technology has attracted much attention from researchers because it can display images in the air, bringing viewers a strong visual impact and a sensory experience that is both real and surreal.

[0003] The required size of the floating image varies depending on the specific application scenario. While various floating display technologies exist, the size of the floating image displayed by the device is typically limited during the manufacturer's design phase and cannot be adjusted during use. Therefore, when users desire different sized floating images for different applications, they usually need to purchase floating display devices of different sizes. For manufacturers of floating display devices, this requires designing different devices for different user needs (especially different optical systems to adapt to different image display units), adapting them one by one, which consumes significant human and material resources.

[0004] Therefore, there is a need in this field for a new technical solution for levitation displays. Summary of the Invention

[0005] The purpose of exemplary embodiments of the present invention is to provide an optical imaging component that can achieve a floating display with a simple structure.

[0006] Specifically, an exemplary embodiment of the present invention provides an optical imaging component for a levitated display, comprising: a plurality of retroreflective screens spaced apart in a first direction; and a polarization beam splitter configured to reflect first polarized light and transmit second polarized light, the first polarized light and the second polarized light having different polarization states; wherein the optical imaging component is configured to receive or emit image light from an object surface via the intervals between the plurality of retroreflective screens, and such that light beams from points on the object surface converge on a first image surface in at least one of the first direction and the second direction, the first direction and the second direction being orthogonal to the principal optical axis of the optical imaging component.

[0007] In the aforementioned optical imaging system, the image light with a large divergence angle passes through the imaging component along the first direction to form an image with a relatively large image aperture angle and does not produce aberrations, thus satisfying the binocular parallax condition. This allows a suspended image to be formed in the air. At the same time, the system has a simple structure and is easy to manufacture.

[0008] Optionally, the microstructure unit of the retroreflector is a dihedral element, which has two adjacent surfaces forming a right angle.

[0009] Optionally, the optical imaging assembly further includes a phase retarder disposed between the plurality of retroreflection screens and the polarization beam splitter, wherein the phase retarder comprises a half-wave plate or a quarter-wave plate.

[0010] Optionally, the axial angle of the polarizing film relative to the first direction or the second direction is 45 degrees or -45 degrees.

[0011] Optionally, the microstructure unit of the retroreflector is a corner prism element having three mutually perpendicular adjacent surfaces.

[0012] Optionally, the image light is either left-handed circularly polarized light or right-handed circularly polarized light, the first polarized light is one of left-handed circularly polarized light and right-handed circularly polarized light, and the second polarized light is the other of left-handed circularly polarized light and right-handed circularly polarized light.

[0013] Optionally, the image light is circularly polarized light, and the optical imaging component further includes a phase retarder, which is disposed between the plurality of retroreflection screens and the polarization beam splitter, the phase retarder including a quarter-wave plate.

[0014] Optionally, the plurality of phase delay slices are spaced apart in the first direction.

[0015] Optionally, the first polarized light is a first linearly polarized light, and the second polarized light is a second linearly polarized light, wherein the first linearly polarized light and the second linearly polarized light are orthogonal to each other.

[0016] Optionally, the optical imaging assembly further includes a transparent substrate, wherein: the plurality of retroreflection screens are disposed on a first surface of the transparent substrate, the phase retardation film is disposed on a second surface of the transparent substrate, and the polarization beam splitter is disposed on the phase retardation film; or the phase retardation film is disposed on the first surface of the transparent substrate, the plurality of retroreflection screens are disposed on the phase retardation film, and the polarization beam splitter is disposed on the second surface of the transparent substrate.

[0017] According to another exemplary embodiment of the present invention, an optical imaging module for a levitated display is also provided, wherein the optical imaging module includes: a first optical imaging component as described above, configured to converge a light beam from a point on the object surface onto a first image surface in one of the first direction and the second direction; and a second optical imaging component as described above, configured to converge a light beam from a point on the object surface onto a second image surface different from the first image surface in the other of the first direction and the second direction.

[0018] Optionally, the retroreflector is a first retroreflector, the polarization beam splitter is a first polarization beam splitter, wherein the second optical imaging component includes: a plurality of second retroreflectors, the plurality of second retroreflectors being spaced apart in a first direction; and a second polarization beam splitter, configured to reflect one of the first polarized light and the second polarized light, and to transmit the other of the first polarized light and the second polarized light; wherein the second optical imaging component is configured to receive or emit the image light via the intervals between the plurality of second retroreflectors.

[0019] Optionally, the first and second retroreflector screens are arranged adjacent to each other, and the gaps between the multiple first retroreflector screens and the gaps between the multiple second retroreflector screens correspond one-to-one.

[0020] Optionally, the optical imaging module further includes a polarizer disposed between the first retroreflective screen and the second retroreflective screen, wherein the absorption axis of the polarizer is at an angle of 45 degrees or -45 degrees relative to the first direction or the second direction.

[0021] Optionally, the second optical imaging component includes one or more lenses for modulating light in the first direction.

[0022] Optionally, the first optical imaging component includes: a first phase retarder disposed between the plurality of retroreflection screens and the polarization beam splitter, wherein the first phase retarder is a half-wave plate; and a second phase retarder disposed between the plurality of retroreflection screens and the second optical imaging component, wherein the second phase retarder is a half-wave plate, wherein the axial angle between the first phase retarder and the second phase retarder is 90 degrees.

[0023] Optionally, the retroreflective screen is a first retroreflective screen, and the second optical imaging component includes a second retroreflective screen, wherein the microstructure units of the first retroreflective screen and the microstructure units of the second retroreflective screen are orthogonally arranged.

[0024] Optionally, the second optical imaging component further includes a reflector, wherein the reflector and the second retroreflector are arranged relatively parallel to each other, and the optical axis of the second retroreflector is perpendicular to the optical axis of the first retroreflector.

[0025] Optionally, the second optical imaging component further includes a second polarization beam splitter. The light beam from the object plane is incident on the second polarization beam splitter, reflected by the second polarization beam splitter to the mirror, reflected by the mirror, transmitted through the second polarization beam splitter into the second retroreflection screen, reflected by the second retroreflection screen, reflected by the second polarization beam splitter, and then propagates toward the first image plane and the second image plane.

[0026] Optionally, the second optical imaging assembly further includes: a second phase retardation film disposed between the second retroreflector and the second polarizing beam splitter; and a third phase retardation film disposed between the reflector and the second polarizing beam splitter.

[0027] Optionally, the second optical imaging component includes a third retroreflective screen, wherein the microstructure units of the third retroreflective screen are orthogonally arranged to the microstructure units of the second retroreflective screen.

[0028] Optionally, the second and third retroreflector screens are arranged relatively parallel to each other, and the optical axes of the second and third retroreflector screens are perpendicular to the optical axis of the first retroreflector screen.

[0029] Optionally, the second optical imaging component further includes a second polarization beam splitter. The light beam from the object plane is incident on the second polarization beam splitter, and after being reflected by the second polarization beam splitter, it enters the third retroreflection screen. After being reflected by the third retroreflection screen, it is transmitted through the second polarization beam splitter into the second retroreflection screen. After being reflected by the second retroreflection screen, it is reflected by the second polarization beam splitter and then propagates toward the first image plane and the second image plane.

[0030] Optionally, the second optical imaging assembly further includes: a second phase retardation film disposed between the second retroreflection screen and the second polarization beam splitter; and a third phase retardation film disposed between the third retroreflection screen and the second polarization beam splitter.

[0031] Optionally, the light beam from the object surface is incident on the first optical imaging component via a polarization beam splitter, reflected by the first retroreflection screen and then reflected by the polarization beam splitter before exiting from the gap between the plurality of first retroreflection screens to the second optical imaging component.

[0032] Optionally, the optical imaging module further includes: a fourth phase retardation film disposed between the first optical imaging component and the second optical imaging component; and a polarizer disposed between the fourth phase retardation film and the second optical imaging component and configured to transmit the first polarized light.

[0033] Optionally, the optical imaging module further includes a polarization converter disposed between the first optical imaging component and the second optical imaging component, and configured to switch the image light passing through it between the first polarized light and the second polarized light.

[0034] Optionally, the polarization converter includes an electronically controlled liquid crystal cell.

[0035] Optionally, the optical imaging module further includes a scattering screen disposed at the second image plane and configured to scatter light along the first direction.

[0036] According to another exemplary embodiment of the present invention, a floating display device is also provided, comprising: an optical imaging module as described above; and an image display configured to emit the image light.

[0037] Optionally, the image display is a three-dimensional display.

[0038] Optionally, the floating display device includes a plurality of optical imaging modules, which are arranged along the first direction.

[0039] Optionally, the levitating display device further includes a diffuser screen disposed at the second image plane and configured to diffuse light along the first direction.

[0040] According to another exemplary embodiment of the present invention, a multilayer display device is also provided, comprising: a suspended display device as described above; and a transparent display device disposed downstream of the optical path of the suspended display device, wherein the display surface of the transparent display device and the suspended image surface are located at different positions.

[0041] Optionally, the transparent display device may include a transparent display or be implemented by projecting an image onto a transparent / semi-transparent film.

[0042] Other features and aspects will become clear from the following detailed description, accompanying drawings, and claims. Attached Figure Description

[0043] The invention can be better understood by describing exemplary embodiments of the invention in conjunction with the accompanying drawings, in which:

[0044] Figure 1 A schematic diagram of an optical imaging assembly 100 for a levitation display according to some embodiments of the present invention is shown;

[0045] Figure 2 A schematic diagram of an optical imaging assembly 200 for a levitation display according to other embodiments of the present invention is shown.

[0046] Figure 3 An example structure of a dihedral element array is shown;

[0047] Figure 4 An example structure of a polarizing beam splitter is shown;

[0048] Figure 5A A schematic diagram of a cholesteric liquid crystal circularly polarized beam splitter is shown.

[0049] Figure 5B A schematic diagram showing the formation of a microstructure unit array along a curved surface in an optical modulation component is shown.

[0050] Figure 5C An example structure of a cylindrical right-angle grating is shown;

[0051] Figure 6 A schematic diagram of an optical imaging assembly 600 for a levitation display according to other embodiments of the present invention is shown;

[0052] Figure 7 A schematic diagram of an optical imaging assembly 700 for a levitation display according to other embodiments of the present invention is shown;

[0053] Figure 8 A schematic diagram of an optical imaging assembly 800 for a levitation display according to other embodiments of the present invention is shown;

[0054] Figure 9A and Figure 9B Example structures of corner prism element arrays are shown respectively;

[0055] Figure 9C A schematic diagram showing the change in polarization state when polarized light is incident on a corner prism;

[0056] Figure 10 A schematic diagram of an optical imaging assembly 1000 for a levitation display according to other embodiments of the present invention is shown.

[0057] Figure 11 A schematic diagram of an optical imaging assembly 1100 for a levitation display according to other embodiments of the present invention is shown;

[0058] Figure 12 A schematic diagram of an optical imaging assembly 1200 for a levitation display according to other embodiments of the present invention is shown;

[0059] Figure 13 A schematic diagram of an optical imaging module 1300 for a levitation display according to some embodiments of the present invention is shown;

[0060] Figure 14 Show Figure 13 A schematic diagram of the light modulation path in the optical imaging module 1300;

[0061] Figure 15 A schematic diagram of an optical imaging module 1500 for a levitation display according to other embodiments of the present invention is shown;

[0062] Figure 16 A schematic diagram of an optical imaging module 1600 for a levitation display according to other embodiments of the present invention is shown;

[0063] Figure 17 A schematic diagram of an optical imaging module 1700 for a levitation display according to other embodiments of the present invention is shown;

[0064] Figure 18A and Figure 18B A schematic diagram of an optical imaging module 1800 for a levitation display according to other embodiments of the present invention is shown;

[0065] Figure 19 A schematic block diagram of a floating display device 1900 capable of suspending image stitching according to an embodiment of the present invention is shown;

[0066] Figure 20 A schematic diagram of a multilayer display device according to an embodiment of the present invention is shown;

[0067] Figure 21 A schematic diagram of a transparent display device achieved through micro-projection is shown;

[0068] Figure 22 A schematic diagram illustrating the implementation of glasses-free 3D display using a multi-layer display device is shown; and

[0069] Figures 23A-23C This is an illustrative diagram showing a display module using a three-dimensional display.

[0070] Figure 24 A schematic diagram of an optical imaging module 2400 for a levitating display according to other embodiments of the present invention is shown. Detailed Implementation

[0071] The following describes specific embodiments of the present invention. It should be noted that, in order to provide a concise description, this specification cannot exhaustively describe all features of the actual embodiments. It should be understood that, in the actual implementation of any embodiment, just as in any engineering or design project, various specific decisions are often made to achieve the developer's specific goals and to meet system-related or business-related constraints, and this can change from one embodiment to another. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, some design, manufacturing, or production modifications based on the technical content disclosed herein are merely conventional technical means and should not be construed as insufficient content of this disclosure.

[0072] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the element or object preceding “comprising” or “including” encompasses the element or object listed following “comprising” or “including” and its equivalents, and do not exclude other elements or objects. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections. The phrase “A is substantially equal to B” is intended to take into account manufacturing tolerances, i.e., the values ​​of A and B can be within ±10% of each other. The phrase “X and Y are substantially orthogonal” is intended to take into account manufacturing tolerances, i.e., the angle between X and Y can be between 80° and 100°. S-rays and P-rays represent two polarization states with orthogonal polarization.

[0073] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions. Similarly, unless otherwise specified, all technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0074] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0075] Furthermore, since the optical path is reversible, the positions of the object plane 10 and the image plane 20 shown in the following embodiments can also be interchanged; that is, various optical imaging components, optical imaging modules, levitation display devices, multilayer display devices, etc. of this application can be used for levitation imaging when used in both the forward and reverse directions. Taking the optical imaging component 100 as an example, when used in the forward direction, the image light can enter the optical imaging component 100 through the gap between the retroreflection screens 110 and exit from the polarization beam splitter 120; when used in the reverse direction, the image light can enter the optical imaging component 100 through the polarization beam splitter 120 and exit from the gap between the retroreflection screens 110.

[0076] Figure 1 A schematic diagram of an optical imaging assembly 100 according to some embodiments of the present invention is shown. See also Figure 1According to an embodiment of the present invention, the optical imaging assembly 100 may include a retroreflection screen group consisting of a plurality of retroreflection screens 110. The plurality of retroreflection screens 110 may be spaced apart in a first direction (e.g., the y-direction). The spacing between the retroreflection screens 110 may be used to receive or emit image light from an object surface. Each retroreflection screen 110 may have a first surface 112 and a second surface opposite to the first surface 112. The retroreflection screen 110 may also include a microstructure unit array 116 disposed on the second surface. Each microstructure unit in the microstructure unit array 116 may have at least two surfaces, the at least two surfaces being perpendicular to each other. The microstructure unit array may be used to retroreflect light so that the light returns in the incident direction.

[0077] The optical imaging assembly 100 may further include a polarization beam splitter 120. The polarization beam splitter 120 may be arranged close to the second surface of the retroreflection screen 110 (e.g., Figure 1 (As shown). The polarization beam splitter 120 can be polarization selective, that is, it can reflect light with a specific polarization state while transmitting light with other polarization states. The polarization beam splitter 120 can be a beam splitting film or a beam splitter plate. In the optical imaging assembly 100, image light emitted from the object plane is incident on one side of the optical imaging assembly 100 through the gap between the retroreflection screens 110. The polarization beam splitter 120 reflects light with a specific polarization state. The reflected light is incident on the second surface of the retroreflection screen 110, and is reflected back by the microstructure unit array 116, causing the light to return in its original direction. The reflected light is then incident again on the polarization beam splitter 120, transmitted, and exits from the other side of the optical imaging assembly 100, ultimately forming an image on the image plane. In short, the light modulation process can include reflection by the polarization beam splitter 120, reflection by the retroreflection screen 110 (specifically, the microstructure unit array therein), and transmission by the polarization beam splitter 120. Thus, the optical imaging component 100 can be used to form a suspended real image of an image in the air (e.g., on an image plane).

[0078] In some embodiments, the image light (divergent light) emitted from point O on the object surface 10 can be circularly polarized light.

[0079] Figure 2 A schematic diagram of an optical imaging assembly 200 according to some embodiments of the present invention is shown. See also Figure 2According to an embodiment of the present invention, the optical imaging assembly 200 may include a retroreflection screen group composed of a plurality of retroreflection screens 210. The plurality of retroreflection screens 210 may be spaced apart in a first direction (e.g., the y-direction). The spacing between the retroreflection screens 210 may be used to receive or emit image light from an object surface. Each retroreflection screen 210 may have a first surface 212 and a second surface opposite to the first surface 212. The retroreflection screen 210 may also include a microstructure unit array 216 disposed on the second surface. Each microstructure unit in the microstructure unit array 216 may be a dihedral element having two adjacent surfaces forming a right angle. Light rays arbitrarily irradiated onto the surface of the dihedral element are partially reflected at their original angle, such as... Figure 3 As shown. The microstructure unit array 216 is used to retroreflect light in a first direction (e.g., the x-direction) so that the light returns in the incident direction. The optical imaging assembly 200 may also include a polarizing beam splitter 220. The polarizing beam splitter 220 may be arranged close to a second surface of the retroreflection screen 210 (e.g., Figure 1 (As shown). The polarization beam splitter 220 has polarization selectivity, meaning it can reflect light with a specific polarization state while transmitting light with other polarization states. For example... Figure 2 As shown, the optical imaging assembly 200 may further include a phase retardation plate 218, which can be disposed between the retroreflection screen 210 and the polarization beam splitter 220. The phase retardation plate 218 can be used to modulate the polarization state of light. Figure 2 In this embodiment, the phase retardation plate 218 can be a half-wave plate, and the angle between the axis of the half-wave plate and the vertical direction can be 22.5° or 67.5°. The polarization beam splitter 220 can be a linear polarization beam splitter and is configured to reflect S-polarized light and transmit P-polarized light.

[0080] like Figure 2As shown, the image light (divergent light) emitted from point O on the object plane 10 can be linearly polarized at 45°. A portion of the image light is reflected or absorbed by the first surface 212 of the retroreflection screen 210 and does not participate in the final imaging. The remaining portion of the image light passes through the gap between the retroreflection screens 210 and is converted into S-polarized light by a half-wave plate. The converted S-polarized light is reflected a second time by the polarization beam splitter 220, passes through the half-wave plate, and is converted into linearly polarized light with a polarization direction of -45°, illuminating the second surface of the retroreflection screen 210. A portion of this light is transmitted through the retroreflection screen 210 (specifically, the microstructure unit array 216 therein) and does not participate in the final imaging. Another portion of the light is reflected twice by the right-angle grating of the retroreflection screen 210, and the reflected light is converted into linearly polarized light with a polarization direction of -45°. The imaging light reflected from the retroreflection screen 210 is converted into P-polarized light after passing through the half-wave plate again, and exits through the polarization beam splitter 220, thus converging at point O' on the image plane 20. Similarly, the light source O can also emit image light that is linearly polarized at -45°. In this case, the polarization beam splitter 220 can be configured to reflect P-polarized light and transmit S-polarized light, thus achieving the above-mentioned light modulation process.

[0081] It is understandable that, since the microstructure unit array 216 of the retroreflection screen 210 is a conjugate imaging unit, the object plane 10 and image plane 20 of the various optical imaging components can be basically symmetrically arranged relative to the retroreflection screen 210. The advantage of using conjugate imaging elements is that the positional relationship (object and image) is conjugate, the image is not magnified, and there are no aberrations.

[0082] In some embodiments, the optical imaging assembly may further include a phase retardation plate disposed between a plurality of retroreflective screens and a polarizing beam splitter. In some embodiments, the plurality of phase retardation plates may be spaced apart in a first direction. In some embodiments, the microstructural units of the retroreflective screens may be dihedral elements having two adjacent surfaces forming a right angle. In some embodiments, the first polarized light may be a first linearly polarized light, the second polarized light may be a second linearly polarized light, and the first linearly polarized light and the second linearly polarized light may be orthogonal to each other.

[0083] In some embodiments, the polarizing beam splitter can be a DBEF structure, such as Figure 4 As shown; alternatively, the polarizing beam splitter can be a metal wire grid; or alternatively, the polarizing beam splitter can be formed by multilayer dielectric coating. Alternatively, the polarizing beam splitter can be a cholesteric liquid crystal circularly polarizing beam splitter, such as... Figure 5A As shown, these films can be flat sheet structures or can be fabricated on microstructures.

[0084] In some embodiments, the microstructure unit array 216 in the retroreflective screen 210 can be formed along a plane, or as shown in the figure. Figure 5BAs shown, it is formed along a curved surface. For example, when the microstructure unit is a dihedral element, the microstructure unit array 216 can be formed as a cylindrical right-angle grating, which is a curved surface in the y-direction and a one-dimensional right-angle grating structure in the x-direction, as shown. Figure 5C As shown.

[0085] Figure 6 A schematic diagram of an optical imaging assembly 600 according to some embodiments of the present invention is shown. See also Figure 6 The optical imaging assembly 600 according to an embodiment of the present invention may include a retroreflection screen group composed of a plurality of retroreflection screens 610. The plurality of retroreflection screens 610 may be spaced apart in a first direction (e.g., the y-direction). The spacing between the retroreflection screens 610 may be used to receive or emit image light from an object surface. Each retroreflection screen 610 may have a first surface 612 and a second surface opposite to the first surface 612. The retroreflection screen 610 may also include a microstructure unit array 616 disposed on the second surface. Each microstructure unit in the microstructure unit array 616 may be a dihedral element having two adjacent surfaces forming a right angle. Light rays arbitrarily irradiated onto the surface of the dihedral element are partially reflected at their original angle, such as... Figure 6 As shown. The microstructure unit array 616 is used to retroreflect light in a first direction (e.g., the x-direction) so that the light returns in the incident direction. The optical imaging assembly 600 may also include a polarizing beam splitter 620. The polarizing beam splitter 620 may be arranged close to a second surface of the retroreflection screen 610 (e.g., Figure 1 (As shown). The polarization beam splitter 620 has polarization selectivity, meaning it can reflect light with a specific polarization state while transmitting light with other polarization states. For example... Figure 2 As shown, the optical imaging assembly 600 may further include a phase retardation plate 618, which can be disposed between the retroreflection screen 610 and the polarization beam splitter 620. The phase retardation plate 618 can be used to modulate the polarization state of light. Figure 6 In this embodiment, the phase retardation plate 618 can be a quarter-wave plate, and the axis of the quarter-wave plate can make an angle of 45° with the vertical direction. The polarization beam splitter 620 can be a linear polarization beam splitter and is configured to reflect S-polarized light and transmit P-polarized light.

[0086] like Figure 6As shown, the image light emitted from point O on the object plane 10 is left-handed circularly polarized light. A portion of the image light is reflected or absorbed by the first surface 612 of the retroreflection screen 610 and does not participate in the final imaging. The remaining portion of the image light passes through the gap between the retroreflection screens 610 and is converted into S-polarized light by a quarter-wave plate. The converted S-polarized light is reflected a second time by the polarization beam splitter 620, passes through the quarter-wave plate, and is converted into right-handed circularly polarized light, which then illuminates the second surface of the retroreflection screen 610. A portion of this light is transmitted through the retroreflection screen 610 (specifically, the microstructure unit array 616 within it) and does not participate in the final imaging, while the other portion is reflected twice by the right-angle grating of the retroreflection screen 610 and remains right-handed circularly polarized light. The right-handed circularly polarized light reflected from the retroreflection screen 610 passes through the quarter-wave plate again and is converted into P-polarized light, which is then emitted through the polarization beam splitter 620 and converges at point O' on the image plane 20. Similarly, the light source O can also emit image light that is right-handed circularly polarized. In this case, the polarization beam splitter 620 can be configured to reflect P-polarized light and transmit S-polarized light, thus achieving the above-mentioned light modulation process.

[0087] Figure 7 A schematic diagram of an optical imaging assembly 700 according to some embodiments of the present invention is shown. The structure of the optical imaging assembly 700 is similar to that of the optical imaging assembly 100. For illustrative purposes, Figure 7 Only one of the multiple retroreflection screens is shown, along with a microstructure unit array 710 and a polarizing beam splitter 720. The microstructure unit array 710 can be a dihedral structure used to retroreflect light so that the light returns in the direction of incidence. The polarizing beam splitter 720 can have a polarization axis of 45 degrees and is configured to reflect -45-degree polarized light and transmit +45-degree polarized light.

[0088] like Figure 7 As shown, the incident light rays from the intervals of the retroreflection screen are linearly polarized light at -45 degrees. The incident light rays strike the polarization beam splitter 720 and are reflected, converting into linearly polarized light at +45 degrees. The converted reflected light rays are then incident on the dihedral corners of the microstructure unit array 710. Each time the light rays are reflected on the dihedral corners, their polarization angle rotates by 90 degrees. After two reflections at the dihedral corners, the polarization angle of the light rays remains at 45 degrees, and the light rays return along the original incident direction, passing through the polarization beam splitter 720 before exiting.

[0089] In some embodiments, the axial angle of the polarizing beam splitter relative to the first or second direction can be 45 degrees or -45 degrees.

[0090] Figure 8 A schematic diagram of an optical imaging assembly 800 according to some embodiments of the present invention is shown. See also Figure 8An optical imaging assembly 800 according to an embodiment of the present invention may include a retroreflection screen group composed of a plurality of retroreflection screens 810. The plurality of retroreflection screens 810 may be spaced apart in a first direction (e.g., the y-direction). The spacing between the retroreflection screens 810 may be used to receive or emit image light from an object surface. Each retroreflection screen 810 may have a first surface 812 and a second surface opposite to the first surface 812. The retroreflection screen 810 may also include a microstructure unit array 816 disposed on the second surface. Each microstructure unit in the microstructure unit array 816 may be a corner prism element having three mutually perpendicular adjacent surfaces, such as... Figure 9A Or as shown in 9B. The microstructure unit array 816 is used to retroreflect light so that the light returns in the direction of incidence. The optical imaging assembly 800 may also include a polarizing beam splitter 820. The polarizing beam splitter 820 may be arranged close to the second surface of the retroreflection screen 810 (e.g., Figure 8 (As shown). The polarization beam splitter 820 has polarization selectivity, meaning it can reflect light with a specific polarization state while transmitting light with other polarization states. The polarization beam splitter 820 can be a circularly polarizing beam splitter film. A circularly polarizing beam splitter film has circular dichroism, meaning the material selectively transmits or reflects one of the two circularly polarized light components with opposite rotation directions in a light beam. For example, the circularly polarizing beam splitter film can be a cholesteric liquid crystal film, in which almost all circularly polarized light with the same rotation direction as the liquid crystal is reflected, while almost all circularly polarized light with the opposite rotation direction is transmitted. For example, the polarization beam splitter 820 can be configured to reflect left-handed circularly polarized light and transmit right-handed circularly polarized light.

[0091] like Figure 8 As shown, the image light emitted from point O on the object plane 10 is left-handed circularly polarized light. A portion of the image light is reflected or absorbed by the first surface 812 of the retroreflection screen 810 and does not participate in the final imaging. The remaining portion of the image light passes through the gap between the retroreflection screens 810 and is incident on the polarization beam splitter 820. The polarization beam splitter 820 reflects the left-handed circularly polarized light onto the second surface of the retroreflection screen 810. Figure 9C As shown, with each reflection, the rotation direction of the circularly polarized light changes once. After being reflected once on each of the three surfaces of the corner prism, it becomes right-handed circularly polarized light before exiting. The reflected right-handed circularly polarized light passes through the polarizing beam splitter 720 and is then focused onto image plane 20 at point O'. Similarly, the light source O can also emit image light as right-handed circularly polarized light. In this case, the polarizing beam splitter 820 can be configured to reflect right-handed circularly polarized light and transmit left-handed circularly polarized light, thus achieving the same light modulation process.

[0092] In some embodiments, the microstructure unit of the retroreflector can be a corner prism element having three adjacent surfaces that are perpendicular to each other.

[0093] Figure 10A schematic diagram of an optical imaging assembly 1000 according to some embodiments of the present invention is shown. See also Figure 10 The optical imaging assembly 1000 according to an embodiment of the present invention may include a retroreflection screen group composed of a plurality of retroreflection screens 1010. The plurality of retroreflection screens 1010 may be spaced apart in a first direction (e.g., the y-direction). The spacing between the retroreflection screens 1010 may be used to receive or emit image light from an object surface. Each retroreflection screen 1010 may have a first surface and a second surface opposite to the first surface. The retroreflection screen 1010 may also include an array of microstructure units disposed on the second surface. Each microstructure unit in the microstructure unit array may be a dihedral element. The optical imaging assembly 1000 may also include a polarizing beam splitter 1020, which may be configured to transmit P-polarized light and reflect S-polarized light. Furthermore, the optical imaging assembly 1000 may also include a phase retardation plate 1030, which may be a half-wave plate and have an axial angle of ±22.5° or ±67.5°. Similar to the retroreflection screens 1010, the phase retardation plates 1030 are also arranged spaced apart in the y-direction. In the optical imaging assembly 1000, the phase retardation film 1030 can correspond one-to-one with the retroreflection screen 1010 and can be attached to the corresponding retroreflection screen 1010. The optical imaging assembly 1000 may also include a polarizer 1040, which is configured to absorb P-polarized light and pass S-polarized light.

[0094] The following is for reference. Figure 10 The imaging process in the optical imaging assembly 1000 is described as follows: The image light emitted from point O is P-polarized light. After the incident image light passes through the polarization beam splitter 1020, a portion of the light is emitted through the gap between the retroreflection screens 1010 and absorbed by the polarizer 1040. The other portion of the light is reflected twice by the retroreflection screen 1010, and after passing through the phase retardation plate 1030 twice, the P-polarized light is converted into S-polarized light. The converted S-polarized light is reflected by the polarization beam splitter 1020, then emitted through the gap between the retroreflection screens 1010, and after passing through the polarizer 1040, it forms image point O'.

[0095] The advantage of the optical imaging component 1000 is that the image light is emitted from the object point O, and the light emitted through the retroreflection screen does not need to be converted by the phase retarder. This overcomes the problem that the phase retarder cannot simultaneously meet the perfect matching of the retardation amount for light with large angles and wide wavelength bandwidth, which causes non-ideal conversion of the polarization state of the light, resulting in problems such as direct light leakage and ghost images.

[0096] In some embodiments, the optical imaging assembly may further include a transparent substrate, wherein a plurality of retroreflection screens may be disposed on a first surface of the transparent substrate, a phase retardation film may be disposed on a second surface of the transparent substrate, and a polarizing beam splitter may be disposed on the phase retardation film; or the phase retardation film may be disposed on the first surface of the transparent substrate, a plurality of retroreflection screens may be disposed on the phase retardation film, and a polarizing beam splitter may be disposed on the second surface of the transparent substrate.

[0097] Figure 11 A schematic diagram of an optical imaging assembly 1100 according to some embodiments of the present invention is shown. Similar to the optical imaging assembly described above, the optical imaging assembly 1110 may include a plurality of retroreflection screens 1110, a polarizing beam splitter 1120, and / or a phase retardation plate 1118. The optical imaging assembly 1110 may also include a transparent substrate 1130. The transparent substrate 1130 may include a first surface 1132 and a second surface 1134 opposite to the first surface 1132. The plurality of retroreflection screens 1110 may be disposed on the first surface 1132 of the transparent substrate 1130, the phase retardation plate 1118 may be disposed on the second surface 1134 of the transparent substrate 1130, and the polarizing beam splitter 1120 may be disposed on the phase retardation plate 1118. In other embodiments, the transparent substrate 1130 may also be disposed between the phase retardation plate 1118 and the polarizing beam splitter 1120. In other words, the retroreflection screen 1110 can be disposed on the phase retardation film 1118, the phase retardation film 1118 can be disposed on the first surface 1132 of the transparent substrate 1130, and the polarizing beam splitter 1120 can be disposed on the second surface 1134 of the transparent substrate 1130. It should be understood that when the optical assembly 1100 does not include the phase retardation film, the retroreflection screen 1110 can be disposed on the first surface 1132 of the transparent substrate 1130, and the polarizing beam splitter can be disposed on the second surface 1134 of the transparent substrate 1130.

[0098] By introducing a transparent substrate 1130 into the optical imaging assembly, interface reflections between multiple films can be reduced, ghosting can be eliminated, and the structural stability and manufacturing convenience of the system can be significantly improved.

[0099] The present invention also provides an optical imaging module for a levitated display. The optical imaging module may include any one of the optical imaging components described above, as a first optical imaging component. The first optical imaging component can converge a light beam from a point on an object surface in one of a first direction and a second direction onto a first image surface.

[0100] The optical imaging module may also include a second optical imaging component. The second optical imaging component enables a light beam from a point on the object plane to converge in another direction (either the first or second direction) onto a second image plane different from the first image plane. The second optical imaging component may be any of the optical imaging components described above, or may have other structures, as detailed below.

[0101] Figure 12 A schematic diagram of an optical imaging module 1200 according to some embodiments of the present invention is shown. For example... Figure 12 As shown, the optical imaging module 1200 may include a first optical imaging component 1210 and a second optical imaging component 1220. Similar to the optical imaging component described above, the first optical imaging component 1210 may include a plurality of first retroreflection screens 1212 arranged in the vertical direction and a first polarization beam splitter 1214.

[0102] The second optical imaging assembly 1220 may include a second retroreflective screen 1222, a second polarizing beam splitter 1224, and a reflector 1226. The reflector 1226 is arranged parallel to the second retroreflective screen 1222, and the optical axis of the second retroreflective screen 1222 may be perpendicular to the optical axis of the first retroreflective screen 1212. Similar to the first retroreflective screen 1212, a microstructure unit 1227 is also provided on the side of the second retroreflective screen 1222 opposite to the reflector 1226, and this microstructure unit 1227 may be orthogonally arranged to the microstructure unit (not shown) of the first retroreflective screen 1212.

[0103] The second polarizing beam splitter 1224 can be disposed between the second retroreflective screen 1222 and the reflector 1226, and can be offset from the y-direction by a certain angle, for example, 45 degrees. The second optical imaging assembly 1220 may further include a first phase retardation film 1228 and a second phase retardation film 1229. The first phase retardation film 1228 can be disposed between the second retroreflective screen 1222 and the second polarizing beam splitter 1224, and the second phase retardation film 1229 can be disposed between the second polarizing beam splitter 1224 and the reflector 1226. Furthermore, the optical imaging module 1200 may also include a polarizer 1230. The polarizer 1230 can be disposed between the first optical imaging assembly 1210 and the second optical imaging assembly 1220.

[0104] exist Figure 12 In the optical imaging assembly 1200, the first polarizing beam splitter 1214 and the second polarizing beam splitter 1224 can be selected as linearly polarizing reflective films and are configured to reflect -45° polarized light and transmit +45° polarized light. The first phase retarder 1228 can be a half-wave plate, while the second phase retarder 1229 can be a quarter-wave plate.

[0105] The following is for reference. Figure 13 This describes the light modulation process in the optical imaging module 1200. A -45° polarized light ray emitted from point O first enters the second optical imaging component 1220, is reflected by the second polarization beam splitter 1224, passes through the second phase retardation plate 1229, and then illuminates the reflecting mirror 1226. It is reflected again by the reflecting mirror 1226 and passes through the second phase retardation plate 1229 twice. After passing through the second phase retardation plate 1229 (a quarter-wave plate), the -45° polarized light is converted to +45° polarized light. The converted +45° polarized light passes through the second polarization beam splitter 1224, passes through the first phase retardation plate 1228, illuminates the second retroreflection screen 1222, and is reflected again by the second retroreflection screen 1222 before passing through the first phase retardation plate 1228. After passing through the first phase retardation plate 1228 (a half-wave plate) twice, the +45° polarized light is converted to -45° polarized light. The converted -45° polarized light is incident on the other side of the second polarization beam splitter 1224 and reflected into the first optical imaging assembly 1210.

[0106] -45° polarized light passes through polarizer 1230 before entering the first optical imaging component 1210. Polarizer 1230 has an absorption axis angle of 45°, its function being to eliminate ghost images of other polarization states in the second optical imaging component. Light is incident through the gaps between the first retroreflection screens 1212 and then reflected by the first polarization beam splitter 1214 (reflecting -45° polarized light and transmitting 45° polarized light), converting its polarization direction to +45° linearly polarized light, which then illuminates the second surface of the first retroreflection screen 1212. A portion of this light is transmitted through the first retroreflection screen 1212 (specifically, its microstructure unit array) without participating in the final imaging; the other portion is reflected twice by the right-angle grating of the first retroreflection screen 1212. The first reflection is -45° linearly polarized light, and the second reflection is converted to +45° linearly polarized light. This light exits through the first polarization beam splitter 1214, thus converging on the image plane. For example, light rays emitted from point o on object plane 10 converge on image plane 1 in the y direction; light rays emitted from point o on object plane 10 converge on image plane 2 in the x direction.

[0107] Figure 14 A schematic diagram of an optical imaging module 1400 according to some embodiments of the present invention is shown. Figure 14 As shown, the optical imaging module 1400 may include a first optical imaging component 1410 and a second optical imaging component 1420. Similar to the optical imaging component 1210 described above, the first optical imaging component 1410 may include a plurality of first retroreflection screens 1412 vertically aligned in the vertical direction, a first polarizing beam splitter 1414, and a first phase retardation plate 1416 disposed between the first retroreflection screens 1412 and the polarizing beam splitter 1414.

[0108] The second optical imaging assembly 1420 may include a second retroreflective screen 1422, a second polarizing beam splitter 1424, and a reflector 1426. The reflector 1426 is arranged parallel to the second retroreflective screen 1422, and the optical axis of the second retroreflective screen 1422 is perpendicular to the optical axis of the first retroreflective screen 1412. Similar to the first retroreflective screen 1412, a microstructure unit (not shown) is also provided on the side of the second retroreflective screen 1422 opposite to the reflector 1426, and this microstructure unit is orthogonally arranged to the microstructure unit (not shown) of the first retroreflective screen 1412. The second polarizing beam splitter 1424 is disposed between the second retroreflective screen 1422 and the reflector 1426, and is offset from the y-direction by a certain angle, for example, 45 degrees. The second optical imaging assembly 1420 may also include a second phase retardation film 1428 and a third phase retardation film 1429. The second phase retardation film 1428 is disposed between the second retroreflective screen 1422 and the second polarizing beam splitter 1424, and the third phase retardation film 1429 is disposed between the second polarizing beam splitter 1424 and the reflector 1426. Furthermore, the optical imaging module 1400 may also include a one-dimensional scattering film 1430. For example... Figure 14 As shown, the one-dimensional scattering film 1430 can be disposed optically downstream of the second optical imaging component 1420.

[0109] exist Figure 14 In the optical imaging assembly 1400, the first polarizing beam splitter 1414 and the second polarizing beam splitter 1424 can be selected as linearly polarizing reflective films and are configured to reflect S-polarized light and transmit P-polarized light. The first phase retarder 1416 and the second phase retarder 1428 can be half-wave plates, while the third phase retarder 1429 can be a quarter-wave plate.

[0110] The following is for reference. Figure 14 This describes the light modulation process in the optical imaging module 1400. The image light emitted from point O is linearly polarized light at 45 degrees, and it is incident through the gap between the first retroreflection screens 1412. The incident light passes through the first phase retardation plate 1416. The first phase retardation plate 1416 is a half-wave plate and is set at an angle of ±22.5 / ±67.5 degrees. The first phase retardation plate 1416 converts the incident image light into 0-degree polarized light. The converted light is reflected by the first polarization beam splitter 1414 onto the second surface of the first retroreflection screen 1412. A portion of the light is transmitted through the first retroreflection screen 1412 (specifically, the microstructure unit array therein) without participating in the final imaging, and another portion of the light is reflected twice by the right-angle grating of the first retroreflection screen 1412. After passing through the half-wave plate again, it is converted into 90-degree polarized light, transmitted through the first polarization beam splitter 1414, and enters the second optical imaging component 1420.

[0111] The incident 90-degree polarized light is reflected by the second polarizing beam splitter 1424, then passes through the third phase retarder 1429 and strikes the reflecting mirror 1426. It is reflected again by the mirror and then passes through the third phase retarder 1429 once more. After passing through the quarter-wave plate of the third phase retarder 1429 twice, the deflection angle of the light becomes 0 degrees. The 0-degree polarized light then passes through the second polarizing beam splitter 1424, passes through the second phase retarder 1428 (with axial angles set at ±22.5 / ±67.5 degrees), strikes the second retroreflection screen 1422, and is reflected again by the screen, passing through the second phase retarder 1428 once more. After passing through the half-wave plate of the second phase retarder 1428 twice, the polarization angle becomes 90 degrees. The 90-degree polarized light then strikes the other side of the second polarizing beam splitter 1424 and is reflected away from the second optical component 1420. Then, the light rays in the Y direction converge at the position of the one-dimensional scattering film 1430 and are scattered by the one-dimensional scattering film 1430; this position is the first image plane position. The light rays in the X direction converge at the second image plane position; this position is the suspended image plane.

[0112] In some embodiments, light rays in both the x and y directions can be modulated by the optical imaging component according to the invention. The optical imaging module may include at least two optical imaging components as described above, namely a first optical imaging component and a second optical imaging component. The first optical imaging component is configured to converge a light beam from a point on the object surface onto a first image surface in one of a first direction and a second direction. The second optical imaging component is configured to converge a light beam from a point on the object surface onto a second image surface different from the first image surface in the other of the first and second directions.

[0113] Figure 15 A schematic diagram of an optical imaging module 1500 according to some embodiments of the present invention is shown. The optical imaging module 1500 includes a plurality of first retroreflective screens 1510 and a first polarizing beam splitter 1520, as well as a plurality of second retroreflective screens 1530 and a second polarizing beam splitter 1540. The microstructure unit arrays on the plurality of first retroreflective screens 1510 and the microstructure unit arrays on the plurality of second retroreflective screens can be orthogonally arranged to each other and can all be dihedral structures. In some embodiments, the first retroreflective screen 1510 can converge light in a first direction, and the second retroreflective screen 1520 can converge light in a second direction. In other embodiments, the first retroreflective screen 1510 can converge light in the second direction, and the second retroreflective screen 1520 can converge light in the first direction. The first polarizing beam splitter 1520 can be configured to reflect 45-degree light and transmit -45-degree light. The second polarizing beam splitter 1540 can be configured to reflect -45-degree light and transmit 45-degree light. Reference is made below. Figure 15The imaging process in the optical imaging module 1500 is described as follows: The image light emitted from point O is 45-degree polarized light. It is incident through the gap between the first retroreflection screens 1510, reflected by the first polarizing beam splitter 1520, and converted into -45-degree polarized light. The reflected -45-degree polarized light is reflected twice by the dihedral structure on the first retroreflection screen 1510, returning along the original incident direction and remaining -45-degree polarized light, before being transmitted through the first polarizing beam splitter 1520. The light transmitted through the first polarizing beam splitter 1520 is incident through the gap between the second retroreflection screens 1530, reflected by the second polarizing beam splitter 1540, and converted into 45-degree polarized light. The reflected 45-degree polarized light is reflected twice by the dihedral structure on the second retroreflection screen 1530, returning along the original incident direction and remaining 45-degree polarized light, thus being transmitted through the second polarizing beam splitter 1540. The transmitted light rays are imaged in the Y direction of space onto image plane 1, and in the X direction of space onto image plane 2, thus forming a suspended image.

[0114] Figure 24 A schematic diagram of an optical imaging module 2400 according to some embodiments of the present invention is shown. The optical imaging module 2400 may include a first module and a second module. The first module may include a first polarizing beam splitter 2410, a plurality of first retroreflective screens 2420, and a polarizer 2430. The second module may include a plurality of second retroreflective screens 2440 and a second polarizing beam splitter 2450. Similar to the optical imaging components described above, the plurality of first retroreflective screens 2420 and the plurality of second retroreflective screens 2440 may be arranged at intervals in the vertical direction, and the positions of the plurality of first retroreflective screens 2420 and the plurality of second retroreflective screens 2440 in the vertical direction correspond one-to-one. Microstructure unit arrays (specific structures not shown) may be provided on the plurality of first retroreflective screens 2420 and the plurality of second retroreflective screens 2440. In the illustrated embodiment, the microstructure unit arrays of the retroreflective screens may all be dihedral elements. The microstructure units of the first retroreflective screens 2420 and the microstructure units of the second retroreflective screens 2440 may be arranged orthogonally to each other. In some embodiments, the first retroreflector 2420 can converge light in a first direction, and the second retroreflector 2440 can converge light in a second direction. In other embodiments, the first retroreflector 2420 can converge light in the second direction, and the second retroreflector 2440 can converge light in the first direction.

[0115] In some embodiments, the first polarizing beam splitter 2410 can be configured to reflect +45° light and transmit -45° light, while the second polarizing beam splitter 2440 can be configured to reflect +45° light and transmit -45° light. The polarizer 2430 can be configured to transmit +45° light and absorb -45° light.

[0116] The following is for reference. Figure 24Describe the optical imaging process in the optical imaging module 2400, where Figure 24 The image light emitted from point O is -45° polarized light. It passes through the first polarization beam splitter 2410 and enters the first module. Looking towards the light transmission direction from left to right, the polarization angle of the image light is the same as the transmission axis of the first polarization beam splitter 2410 (the -45° polarized light passes through the first polarization beam splitter 2410). Part of the incident light exits through the gaps between the multiple first retroreflection screens 2420 and is absorbed by the polarizer 2430. Another part of the incident light is reflected twice by the multiple first retroreflection screens 2420 (specifically, reflected by dihedral elements on the retroreflection screens), maintaining a polarization angle of -45°, and then strikes the first polarization beam splitter 2410. Looking at the light transmission direction from right to left, the transmission axis of the first polarizing beam splitter 2410 becomes +45°. The polarization angle (-45°) of the light reflected by the first retroreflection screen 2420 and the transmission axis angle of the first polarizing beam splitter 2410 become orthogonal. Therefore, the light reflected by the first retroreflection screen 2420 can be reflected by the first polarizing beam splitter 2410. The polarization angle of the light reflected by the first polarizing beam splitter 2410 changes to +45°. The reflected light passes through the gaps between the multiple first retroreflection screens 2420 and enters the second module through the polarizer 2430. The +45° polarized light passing through the polarizer 2430 is then directed towards the second polarizing beam splitter 2450 through the gaps between the multiple second retroreflection screens 2440. Looking at the light transmission direction from left to right, the polarization angle of the incident light (+45°) is orthogonal to the transmission axis (-45°) of the second polarization beam splitter 2450, and the light is reflected by the second polarization beam splitter 2450. The polarization angle of the light reflected by the second polarization beam splitter 2450 is converted to -45° and it is directed towards multiple second retroreflection screens 2440. Part of the light enters the gap between the multiple second retroreflection screens 2440 and is absorbed by the polarizer 2430, while the other part of the light is reflected twice by the multiple second retroreflection screens 2440 and retains a polarization angle of -45° before being directed towards the second polarization beam splitter 2450. Looking at the light transmission direction from right to left, the polarization angle (-45°) of the light reflected by the multiple second retroreflection screens 2440 is in the same direction as the transmission axis (-45°) of the second polarization beam splitter 2450, and the light reflected by the multiple second retroreflection screens 2440 can pass through the second polarization beam splitter 2450. The light rays emitted from the second polarizing beam splitter 2450 are imaged in the Y direction in space to form a first image plane, and in the X direction in space to form a second image plane. The second image plane is a suspended image plane.

[0117] In the optical imaging module 2400, because the first retroreflector screen 2420 and the second retroreflector screen 2440 are arranged adjacently, and the gaps between the multiple first retroreflector screens 2420 and the gaps between the multiple second retroreflector screens 2440 correspond one-to-one (for example, the projections of the gaps between the multiple first retroreflector screens 2420 and the gaps between the multiple second retroreflector screens 2440 on the xy plane partially or completely overlap), almost all the light emitted from the first module enters the second module, resulting in a higher energy utilization rate compared to the second module. Figure 15 The improved implementation doubles the performance. This optical architecture offers advantages such as simple structure, low cost, easy assembly, and low light leakage / ghosting.

[0118] Figure 16 A schematic diagram of an optical imaging assembly 1600 according to an optional embodiment of the present invention is shown. The optical imaging assembly 1600 may consist of assembly 1 and assembly 2. Specifically, the optical imaging assembly 1600 may include a polarizing beam splitter 1610, a first phase retardation plate 1620, a one-dimensional retroreflection screen 1630, and a second phase retardation plate 1640, wherein the first phase retardation plate 1620 and the second phase retardation plate 1640 may be half-wave plates, and their axes may be set at ±22.5° or ±67.5°. The axial angle between the first phase retardation plate 1620 and the second phase retardation plate 1640 may be 90 degrees. The advantage of this setting is that the polarization state of light of different wavelengths can be perfectly converted to the incident polarization state after passing through the first and second phase retardation plates, thereby improving the problem of light leakage due to polarization of different wavelengths.

[0119] The example optical imaging assembly 1600 may further include a first lens 1650, a second lens 1660, a third lens 1670, and a fourth lens 1680. In this example, the retroreflective screen 1630 in the optical imaging assembly 100 can be used to modulate the imaging light in the x-direction for imaging, while the first lens 1650, the second lens 1660, the third lens 1670, and the fourth lens 1680 can be used to modulate the imaging light in the y-direction for imaging.

[0120] In some embodiments, the first lens 1650, the second lens 1660, the third lens 1670, and the fourth lens 1680 can be cylindrical lenses. Specifically, the imaging process is as follows: the light emitted from point O is s-polarized light. After passing through component 2, it illuminates the second phase retardation plate 1640. After passing through the second phase retardation plate 1640, the polarization angle is converted to 45°. It then illuminates the first phase retardation plate 1620 through the spaced portion of the one-dimensional retroreflection screen 1630. Because the angle between the first phase retardation plate 1620 and the second phase retardation plate 1640 is 90 degrees, the polarization state of the light after passing through the first phase retardation plate 1620 is converted back to s-polarized light. Then the light is reflected by the polarization beam splitter 1610, and the reflected light is directed onto the one-dimensional retroreflection screen 1630. Part of the light is transmitted through the one-dimensional retroreflection screen 1630 (specifically, the microstructure unit array therein) without participating in the final imaging, while the other part of the light is reflected twice by the right-angle grating of the one-dimensional retroreflection screen, and after passing through the first phase delay plate 1620 again, the polarization state is converted into P-polarized light and then passes through the polarization beam splitter 1610.

[0121] Thus, the image light on the object plane 10 can form a suspended image on the image plane 20 via the example optical imaging component 1600.

[0122] Figure 17 A schematic diagram of an optical imaging module 1700 according to some embodiments of the present invention is shown. For example... Figure 17 As shown, the optical imaging module 1700 may include a first optical imaging component 1710 and a second optical imaging component 1720. Similar to the optical imaging component 200 described above, the first optical imaging component 1710 may include a plurality of first retroreflection screens 1712 vertically aligned in the vertical direction, a first polarizing beam splitter 1714, and a first phase retardation plate 1716 disposed between the first retroreflection screens 1712 and the first polarizing beam splitter 1720.

[0123] The second optical imaging assembly 1720 may include a second retroreflective screen 1722, a second polarizing beam splitter 1724, and a third retroreflective screen 1726. The third retroreflective screen 1726 is arranged parallel to the second retroreflective screen 1722, and the optical axis of the second retroreflective screen 1722 is perpendicular to the optical axis of the first retroreflective screen 1712. Similar to the first retroreflective screen 1712, a microstructure unit 1727 is also provided on the side of the second retroreflective screen 1722 opposite to the third retroreflective screen 1726, and this microstructure unit 1727 is orthogonally arranged to the microstructure unit of the first retroreflective screen 1712. The second polarizing beam splitter 1724 is disposed between the second retroreflective screen 1722 and the third retroreflective screen 1726, and is offset from the y-direction by a certain angle, for example, 45 degrees. The second optical imaging assembly 1720 may also include a second phase retardation film 1728 and a third phase retardation film 1729. The second phase retardation film 1728 is disposed between the second retroreflection screen 1722 and the second polarizing beam splitter 1724, and the third phase retardation film 1729 is disposed between the second polarizing beam splitter 1724 and the third retroreflection screen 1726. Furthermore, the optical imaging module 1700 may also include a fourth phase retardation film 1730, a polarizer 1740, and a one-dimensional scattering film 1750. The fourth phase retardation film 1730 and the polarizer 1740 may be disposed between the first optical imaging assembly 1710 and the second optical imaging assembly 1720. The polarizer 1740 may be disposed between the fourth phase retardation film 1730 and the second optical imaging assembly 1720. The one-dimensional scattering film 1750 may be disposed outside the second optical imaging assembly 1720.

[0124] exist Figure 17 In the optical imaging assembly 1700, the first polarization beam splitter 1714 and the second polarization beam splitter 1724 can be selected as linear polarization reflective films and are configured to reflect S-polarized light and transmit P-polarized light. The first phase retarder 1716, the second phase retarder 1728, the third phase retarder 1729 and the fourth phase retarder 1730 can be half-wave plates.

[0125] The following is for reference. Figure 17This describes the light modulation process in the optical imaging module 1700. P-polarized light with a polarization angle of 0° is emitted from point O, passes through the first polarization beam splitter 1714, and then through the first phase retardation plate 1716. The first phase retardation plate 1716 is a half-wave plate with an axial angle of 22.5°. The polarization angle of the P-polarized light passing through the first phase retardation plate 1716 is converted to 45°. The converted 45° linearly polarized light is directed towards the first retroreflection screen 1712 and reflected back by the first retroreflection screen 1812 (specifically, reflected by the microstructure units on the first retroreflection screen 1712). The reflected light passes through the first phase retardation plate 1716 again and is converted into S-polarized light (polarization angle of 90°). In the y-direction, the light converges again at the position of the first polarization beam splitter 1814, forming a relay image plane. The light is reflected by the first polarization beam splitter 1714, passes through the first phase retardation plate 1716 again, is converted to a polarization angle of 45 degrees, and then is directed towards the first retroreflection screen 1712. The converted 45° polarized light passes through the gap between the first retroreflection screens 1812, then through the fourth phase retardation plate 1730. The axial angle of the fourth phase retardation plate 1730 is set to 112.5° (-67.5°), and it is converted into S-polarized light with a polarization angle of 90°. The S-polarized light then passes through the polarizer 1740 and enters the second optical imaging assembly 1720. The polarizer 1740 is configured to allow S-polarized light with a polarization angle of 90° to pass through.

[0126] The incident S-polarized light is reflected by the second polarization beam splitter 1724, strikes the second retroreflector screen 1722, and is reflected back by the second retroreflector screen 1722. The reflected light passes twice through the second phase retarder 1728 and is converted into P-polarized light. The converted P-polarized light is transmitted through the second polarization beam splitter 1724 and strikes the third retroreflector screen 1726. The arrangement direction of the third retroreflector screen 1726 is orthogonal to the arrangement direction of the first retroreflector screen 1712 and the second retroreflector screen 1722, and is used to modulate the light in the x-direction. The light reflected by the third retroreflector screen 1726 passes twice through the third phase retarder 1729 and is converted into S-polarized light, and is reflected by the second polarization beam splitter 1724 and exits the second optical imaging assembly 1720.

[0127] During the above light modulation process, the light rays are modulated in the y-direction by the first retroreflection screen 1712 and the second retroreflection screen 1722, and converge at the scattering screen position to form image plane 1. The light rays are modulated in the x-direction by the third retroreflection screen 1726, and converge at the image plane 2 position to form a floating image.

[0128] Figure 18A and Figure 18BA schematic diagram of an optical imaging module 1800 according to some embodiments of the present invention is shown. The structure of the optical imaging module 1800 is basically similar to that of the optical imaging module 1700 in FIG18, except that: a liquid crystal cell 1850 may be included between the fourth phase retardation film 1830 and the polarizer 1840 in the optical imaging module 1800. The liquid crystal cell 1850 changes the arrangement of liquid crystal molecules by applying a voltage, thereby changing the polarization angle of the polarized light.

[0129] The optical imaging module 1800 uses a time-division multiplexing method to create two suspended image planes. The image light emitted from point O is P-polarized light (polarization angle 0 degrees), and the polarizer 1840 has a polarization angle of 90 degrees, allowing S-polarized light to pass through while absorbing P-polarized light. For example... Figure 18A As shown, at the first moment, the light rays emitted directly through the first retroreflector screen 1812 have a polarization angle of 0 degrees and are p-polarized light. After being reflected by the first retroreflector screen 1812, the emitted light rays are polarized at 90 degrees and are S-polarized light. The liquid crystal cell 1850 is not powered, and the liquid crystal molecules are arranged with a 90-degree rotation. When light passes through the liquid crystal cell 1850, p-polarized light is converted to S-polarized light, and S-polarized light is converted back to p-polarized light. The S-polarized light that directly passes through the first optical imaging component 1820 passes through the polarizer 1840 and enters the second optical imaging component 1820, forming image plane 1 and image plane 2, with image plane 2 suspended from image plane 1. The p-polarized light emitted after being reflected by the first optical imaging component 1810 is absorbed by the polarizer 1640.

[0130] like Figure 18B As shown, at the second moment, the liquid crystal cell 1850 is powered on, the liquid crystal molecules are vertically aligned, and the polarization angle of the incident light is not changed. The light that passes directly through the first optical imaging component 1810 is P-polarized light, which is absorbed by the polarizer 1840. The light that is reflected by the first optical imaging component 1810 is S-polarized light, which passes through the polarizer 1840 and enters the second optical imaging component to form image plane 1 and image plane 3. Image plane 3 is a suspended image plane 2.

[0131] Figure 19 A schematic block diagram of a floating display device 1900 capable of suspending image stitching according to an embodiment of the present invention is shown. See also Figure 19 The floating display device 1900 according to an embodiment of the present invention may include a display module 1910 and a plurality of optical imaging modules 1920. 1～n Optical imaging module 1920 i It can be composed of the optical imaging components described above. The display module 1910 can be configured to emit display light that constitutes the target image. Multiple optical imaging modules 1920 1～n It can be configured to receive display light emitted from display module 1910 to form a levitating image in the air. Each optical imaging module 1920 iThe object plane 10 and image plane 20 are defined. The display module 1910 (specifically its display surface) is arranged at the object plane 10 of the plurality of optical imaging modules. Light emitted from the pixels on the display module 1910 can pass through the plurality of optical imaging modules 1920. 1～n One or more optical imaging modules converge on the image plane 20.

[0132] In embodiments of the present invention, the display module 1910 may be composed of multiple display units spliced ​​together or may be a single display device. The single display device may be a single complete display area or have multiple independent display areas. Thus, the display module 1910 may include multiple display sections arranged along the y-direction. Each display section may be configured to display a corresponding portion of a target image. In some embodiments, the display module 1910 may be a display.

[0133] According to another exemplary embodiment of the present invention, a multilayer display device is also provided.

[0134] Figure 20 A schematic diagram of a multilayer display device 2000 according to an embodiment of the present invention is shown.

[0135] The multilayer display device 2000 may include the aforementioned suspended display device 1900 and transparent display device 2020. The transparent display device 2020 may be disposed on the light-emitting side (downstream optically) of the suspended display device 1900. The display surface of the transparent display device 2020 is located at a different position from the suspended image surface 20 of the suspended display device 1900, specifically between the suspended image surface 20 and the suspended display device 1900. The transparent display device 2020 may have high transmittance, such as a transparent OLED / LED / LCD display or a film (slide). The transparent display device 2020 may also obtain an image by micro-projection through a transparent film (with a haze of less than 5%) placed in front of the suspended display device 1900. Figure 21 As shown. Alternatively, the transparent film can be angularly selective in its light transmission, scattering large-angle light (projected image) and allowing small-angle light to pass through directly (suspended image).

[0136] The above describes a multi-layer display device 2000 according to an exemplary embodiment of the present invention. The multi-layer display device 2000 has a display surface 1 and a display surface 2. A floating display device 1900 can form a floating image on the display surface 1 (image surface 20), and a transparent display device 2020 can display different information on the display surface 2. Thus, secondary information can be displayed on the display surface 2, while important information is presented on the display surface 1, thereby improving the efficiency and experience of information acquisition. Alternatively, images of the same size can be displayed on both the display surface 1 and the display surface 2. By utilizing the differences in light and color caused by the varying distances of objects from the viewer, the images of objects can be superimposed, creating a sense of depth for the viewer, thereby achieving naked-eye 3D display, such as... Figure 20 As shown.

[0137] Optionally, the display module 2310 can also be a glasses-free 3D display, which can be a multi-viewpoint free-view stereoscopic display or a light field display. For example... Figure 23A As shown, a typical glasses-free 3D display consists of a flat panel display and micro-optical units, which can be microlenses or slit gratings. The flat panel display generates a parallax image, which is then sent to the observer's left and right eyes respectively after passing through the micro-optical units. Utilizing the binocular parallax effect of the human eye, a stereoscopic effect is created. Figure 23B As shown, point a1 on display module 2310 enters the right eye, and point a2 enters the left eye. Due to the principle of binocular parallax, the human eye sees point a, which is in front of the screen. Point b1 on the display enters the right eye, and point b2 enters the left eye. Due to the principle of binocular parallax, the human eye sees point b, which is behind the screen. Both eyes see point c on the screen, thus perceiving the position of point c as being on the screen. Therefore, the 3D image presented by a traditional naked-eye 3D display is a 3D image within a certain depth range in front of and behind the screen, with the screen as the depth center. Because the human eye focuses on the physical screen of the 3D display when viewing, it is impossible to perceive the 3D image floating in space, affecting the viewing experience.

[0138] The display module 2310 in this invention can employ a multi-viewpoint / light field display, which effectively solves this problem. The screen of the multi-viewpoint / light field display is projected into space through the optical imaging module 2320 of this invention, forming a suspended image surface. By displaying a parallax image on the multi-viewpoint / light field display, a 3D image can be formed in space with the suspended image surface as the depth center and within a certain range in front and behind. Figure 23C As shown, on the floating image surface, point b is in the foreground depth plane, point a is in the background depth plane, and point c is on the floating image surface of the display device. The resulting 3D image is completely floating in the air, providing a better 3D effect experience.

[0139] The optical imaging component, optical imaging module, levitation display device, and multilayer display device according to exemplary embodiments of the present invention have been described in detail above. The advantages of the present invention are: 1) The optical imaging component / module has a simple structure and is easy to manufacture, effectively reducing costs; 2) It can be an aberration-free system, requiring no correction of optical aberrations, and has a large field of view; 3) Various sizes of display modules (or a specific number of display units) and a specific number of optical imaging components / modules can be used as needed to achieve levitation displays of different sizes, allowing for immediate use, which is particularly beneficial for achieving large-size levitation displays; 4) The optical imaging component / module is designed at once, and the corresponding number of the same optical imaging modules can be used to seamlessly stitch the levitation image according to the required levitation image size, without needing to design different optical imaging components / modules for different levitation image sizes; 5) Fewer ghosting artifacts. Using this optical imaging component / module, the light field reconstruction of image light in the air is achieved, which is a three-dimensional light field display technology. The image-side aperture angle of the image light imaged by the optical imaging component / module along the x-direction is relatively large, satisfying the binocular parallax condition, thereby enabling the levitation display of the image.

[0140] It should be understood that the above description is illustrative and not restrictive. For example, the above embodiments (and / or aspects thereof) can be used in combination with each other. Furthermore, many modifications can be made to adapt particular conditions or materials to the teachings of the various embodiments of the invention without departing from the scope of the invention. While the dimensions and types of materials described herein are used to define parameters of the various embodiments of the invention, the embodiments are not intended to be restrictive but are exemplary. Many other embodiments will become apparent to those skilled in the art upon reading the above description. Therefore, the scope of the various embodiments of the invention should be determined by reference to the appended claims and the full scope of their equivalents.

Claims

1. An optical imaging component for a levitation display, comprising: Multiple retroreflecting screens are spaced apart in a first direction; and A polarization beam splitter is configured to reflect a first polarized light and transmit a second polarized light, wherein the first polarized light and the second polarized light have different polarization states. The optical imaging component is configured to receive or emit image light from an object surface via the intervals between the plurality of retroreflector screens, and to converge the light beam from a point on the object surface onto a first image surface in at least one of a first direction and a second direction, wherein the first direction and the second direction are respectively orthogonal to the principal optical axis of the optical imaging component.

2. The optical imaging assembly as claimed in claim 1, characterized in that, The microstructure unit of the retroreflective screen is a dihedral element, which has two adjacent surfaces forming a right angle; or The microstructure unit of the retroreflector screen is a corner prism element, which has three adjacent surfaces that are perpendicular to each other.

3. The optical imaging assembly as described in claim 2, characterized in that, The axial angle of the polarizing beam splitter relative to the first direction or the second direction is 45 degrees or -45 degrees.

4. The optical imaging component as described in any one of claims 1-3, characterized in that, The optical imaging component also includes: A phase delay plate is disposed between the plurality of retroreflection screens and the polarization beam splitter.

5. The optical imaging assembly as claimed in claim 4, characterized in that, The plurality of phase delay plates are spaced apart in the first direction.

6. The optical imaging assembly as claimed in claim 1, characterized in that, The optical imaging assembly further includes a transparent substrate, wherein: The plurality of retroreflection screens are disposed on a first surface of the transparent substrate, the phase retarder is disposed on a second surface of the transparent substrate, and the polarizing beam splitter is disposed on the phase retarder; or The phase retarder is disposed on the first surface of the transparent substrate, the plurality of retroreflection screens are disposed on the phase retarder, and the polarization beam splitter is disposed on the second surface of the transparent substrate.

7. An optical imaging module for levitational displays, comprising: The first optical imaging component as claimed in any one of claims 1-6 is configured to converge a light beam from a point on the object surface onto the first image surface in one of the first direction and the second direction; and The second optical imaging component is configured to converge a light beam from a point on the object surface onto a second image surface that is different from the first image surface in another direction between the first direction and the second direction.

8. The optical imaging module as described in claim 7, characterized in that, The retroreflection screen is a first retroreflection screen, the polarization beam splitter is a first polarization beam splitter, and the second optical imaging component includes: Multiple second retroreflector screens, the multiple second retroreflector screens being spaced apart in a first direction; and The second polarization beam splitter is configured to reflect one of the first polarized light and the second polarized light, and to transmit the other of the first polarized light and the second polarized light; The second optical imaging component is configured to receive or emit the image light via the interval between the plurality of second retroreflector screens.

9. The optical imaging module as described in claim 8, characterized in that, The first and second retroreflector screens are arranged adjacent to each other, and the gaps between the multiple first retroreflector screens and the gaps between the multiple second retroreflector screens correspond one-to-one.

10. The optical imaging module as described in claim 7, characterized in that, The second optical imaging component includes one or more lenses for modulating light in the first direction or the second direction.

11. The optical imaging module as described in claim 7, characterized in that, The retroreflecting screen is a first retroreflecting screen, and the second optical imaging component includes a second retroreflecting screen, wherein the microstructure units of the first retroreflecting screen and the microstructure units of the second retroreflecting screen are orthogonally arranged.

12. The optical imaging module as described in claim 11, characterized in that, The second optical imaging component also includes a reflector, which and the second retroreflector are arranged relatively parallel to each other, and the optical axis of the second retroreflector is perpendicular to the optical axis of the first retroreflector.

13. The optical imaging module as described in claim 11, characterized in that, The second optical imaging component includes a third retroreflective screen, wherein the microstructure units of the third retroreflective screen are orthogonally arranged to the microstructure units of the second retroreflective screen.

14. The optical imaging module as described in claim 7, characterized in that, The optical imaging module also includes: A polarization converter is disposed between the first optical imaging component and the second optical imaging component, and is configured to switch the image light passing through it between the first polarized light and the second polarized light.

15. A floating display device, comprising: The optical imaging module as described in any one of claims 7-14; as well as An image display configured to emit the image light.

16. A multilayer display device, comprising: The floating display device as described in claim 15; as well as A transparent display device is disposed downstream of the optical path of the suspended display device, wherein the display surface of the transparent display device and the suspended image surface are located at different positions.

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