Optical imaging assembly, optical imaging module and device

Abstract

The present application relates to a kind of optical imaging assembly for levitation display, optical imaging module, levitation display device and multilayer display equipment.The optical imaging assembly includes: transparent light modulation component, with first surface and second surface opposite to first surface;Splitting layer is formed in light modulation component, splitting layer has microstructure unit array, each microstructure unit in microstructure unit array has at least two surfaces, at least two surfaces are perpendicular to each other and form with first light splitting film on it, microstructure unit array is used to back reflection in at least first direction to light so that the light is returned in the direction of incidence;And second light splitting film.

Description

TECHNICAL FIELD

[0001] Embodiments described herein relate generally to light field three-dimensional display technology, and more particularly to an optical imaging assembly, an optical imaging module, a levitation display device and a multi-layer display apparatus. BACKGROUND

[0002] Among numerous display technologies, levitation display technology has attracted much attention of researchers due to its ability to present images in the air, which brings strong visual impact and a real-false sensory experience to the viewer.

[0003] Conventional levitation display technologies include using a retro-reflective screen, a lens group or integrated imaging to realize levitation display. However, for the retro-reflective screen or lens group, the display system is bulky, and as the size of the levitation image increases, the volume of the display system also needs to be increased; for the integrated imaging, many micro display units are needed to project to form a levitation image in space, it is difficult to achieve high resolution, and the screen cost is too high.

[0004] In addition, for different scene requirements, the required size of the levitation image is different. In the prior art, although there are various levitation display technologies as described above, the size of the levitation image displayed by the levitation display device is generally limited at the design stage of the manufacturer, and cannot be adjusted during use. Thus, when the user expects to present levitation images of different sizes according to different application scenarios, it is usually necessary to purchase levitation display devices of different sizes. For the manufacturer of the levitation display device, it is necessary to design different levitation display devices (especially different optical systems to adapt to different size image display units) to adapt to different user needs one by one, which consumes a lot of manpower and resources.

[0005] Therefore, there is a need in the art for a new technical solution for levitation display. SUMMARY

[0006] It is an object of exemplary embodiments of the present application to provide an optical imaging assembly that can realize levitation display with a simple structure.

[0007] In particular, the exemplary embodiments of the present application provide an optical imaging assembly, comprising: a transparent light modulating component having a first surface and a second surface opposite to the first surface; a light splitting layer formed in the light modulating component, the light splitting layer having an array of micro-structure units, each of the array of micro-structure units having at least two surfaces perpendicular to each other and a first light splitting film formed thereon, the array of micro-structure units being configured to retro-reflect a light ray in at least a first direction to return the light ray in an incident direction; and a second light splitting film; wherein an image light incident to one of the first surface and the second surface of the light modulating component is modulated by the light splitting layer and the second light splitting film to exit from the other of the first surface and the second surface, the modulation including retro-reflection by the array of micro-structure units, reflection by the second light splitting film, and transmission by the array of micro-structure units.

[0008] In the optical imaging system described above, the image light having a larger divergence angle is imaged by the imaging assembly along the first direction through a relatively large image-side aperture angle and without generating aberration, satisfying the binocular parallax condition, so that a floating image can be formed in the air, while the structure of the system is simple and easy to manufacture.

[0009] Preferably, each micro-structure unit is a dihedral element having two adjacent surfaces forming a right angle, or an angular prism element having three adjacent surfaces perpendicular to each other.

[0010] Preferably, one of the first light splitting film and the second light splitting film is a polarization light splitting film, and the other is a light intensity light splitting film.

[0011] Preferably, an angle between a polarization axis of the polarization light splitting film and the first direction is set to 45 degrees or 135 degrees.

[0012] Preferably, the optical imaging assembly further comprises a phase retardation plate arranged between the light modulating component and the second light splitting film. Optionally, the phase retardation plate is a quarter-wave plate.

[0013] Preferably, the second light splitting film is a polarization light splitting film, and is arranged outside the first surface of the light modulating component or between the first surface of the light modulating component and the light splitting layer.

[0014] Preferably, the first light splitting film is a polarization light splitting film, and the second light splitting film is arranged outside the second surface of the light modulating component or between the second surface of the light modulating component and the light splitting layer.

[0015] Preferably, the optical imaging assembly further comprises a polarizer or a combination of a polarizer and a phase retarder disposed outside the second surface of the light modulating component. Optionally, the optical imaging assembly further comprises a linear polarizer or a circular polarizer for reducing the reflection of ambient light by the polarization beam splitter.

[0016] Preferably, the light splitting layer divides the light modulating component into a first medium portion and a second medium portion, the first medium portion and the second medium portion having the same refractive index. Optionally, the refractive index of the first medium portion and the second medium portion is between 1.3 and 1.8. Optionally, there is a plurality of media between the light modulating component and the second light splitting film, the plurality of media having a refractive index that is less than 0.3 different from the refractive index of the first medium portion and the second medium portion. Optionally, the first medium portion and the second medium portion are formed of isotropic material.

[0017] Preferably, the array of microstructure units is formed along a plane or a curved surface.

[0018] Preferably, the object plane and the image plane of the optical imaging assembly are substantially symmetrically disposed with respect to the light splitting layer.

[0019] Preferably, the light modulating component is configured to image in a first direction, the optical imaging assembly further comprising an imaging light group configured to image in a second direction, the first direction and the second direction being orthogonal to an optical axis of the optical imaging assembly. Optionally, the array of microstructure units is a one-dimensional rectangular grating array, and the light modulating component is integrated with a lens, the lens being configured to modulate the imaging light in the second direction. Optionally, the imaging light group comprises one or more lenses. Optionally, one of the one or more lenses is a second direction aperture stop of the optical imaging assembly. Optionally, the one lens is a Fresnel lens, the teeth of the Fresnel lens being disposed at equal intervals.

[0020] Preferably, the optical imaging assembly further comprises a one-dimensional grating transmission array, the array of microstructure units being a one-dimensional rectangular grating array, the one-dimensional grating transmission array being substantially orthogonal to the one-dimensional rectangular grating array. Preferably, the light intensity splitting film is a depolarized light intensity splitting film, wherein |Rs-Rp|≤10%.

[0021] Preferably, the distance between the second light splitting film and the light splitting layer is between 0 and 100 μm.

[0022] Preferably, the optical imaging system further comprises a light filtering element between the first light splitting film and the second light splitting film for passing light rays within a predetermined angular range.

[0023] According to yet another exemplary embodiment of the present application, there is also provided an optical imaging module for levitation display, characterized in that the optical imaging module comprises two optical imaging assemblies as described above, and the first array of microstructure units in the first optical imaging assembly is arranged substantially orthogonally with respect to the second array of microstructure units in the second optical imaging assembly, and each of the first and second microstructure units is a dihedral element.

[0024] According to yet another exemplary embodiment of the present application, there is also provided a levitation display device, comprising one or more optical imaging assemblies as described above and / or one or more optical imaging modules as described above; and an image display module configured to emit the image light.

[0025] Preferably, the image display module is a three-dimensional display.

[0026] According to yet another exemplary embodiment of the present application, there is also provided a multi-layer display device, comprising a levitation display device as described above; and a transparent display device arranged optically downstream of the levitation display device, wherein a display surface of the transparent display device is located at a different position from a levitation image surface.

[0027] Preferably, the transparent display device comprises a transparent display or is realized by projecting an image onto a transparent / semi-transparent film.

[0028] Other features and aspects will become apparent from the following detailed description, drawings, and claims. BRIEF DESCRIPTION OF DRAWINGS

[0029] The present application can be better understood with reference to the following examples of embodiments described in connection with the following drawings, in which:

[0030] Figure 1 A schematic diagram of an optical imaging system 100 for levitation display according to some embodiments of the present application is shown;

[0031] Figure 2 An example structure of an array of dihedral elements is shown;

[0032] Figure 3 A schematic diagram of an optical imaging system 300 according to some other embodiments of the present application is shown;

[0033] Figure 4 A schematic diagram of an optical imaging assembly 400 according to some other embodiments of the present application is shown;

[0034] Figure 5 A schematic diagram of an optical imaging assembly 500 according to some other embodiments of the present application is shown;

[0035] Figure 6A and Figure 6B showing example structures of an array of corner cube elements, respectively;

[0036] Figure 7 showing a schematic diagram of a change in polarization state of polarized light illuminating a corner cube;

[0037] Figure 8 showing a schematic diagram of an optical imaging assembly 800 according to further embodiments of the application;

[0038] Figure 9 showing a schematic diagram of an optical imaging assembly 900 according to further embodiments of the application;

[0039] Figure 10 showing a schematic diagram of an optical imaging assembly 1000 according to further embodiments of the application;

[0040] Figure 11 showing a schematic diagram of an optical imaging assembly 1100 according to further embodiments of the application;

[0041] Figure 12 showing an example structure of a polarization splitting film;

[0042] Figure 13 showing a schematic diagram of a cholesteric liquid crystal round polarization splitting film;

[0043] Figure 14 showing a schematic diagram of light propagation when the refractive indices of the media on both sides of the light splitting layer are different;

[0044] Figure 15 showing possible paths of ghost images;

[0045] Figure 16 showing possible paths of ghost images when there is an air layer between the light modulation component 110 and the second light splitting film 120;

[0046] Figure 17 showing an example of a super-fine louver structure;

[0047] Figure 18 showing an example position of an optional light filtering element in the optical imaging assembly;

[0048] Figure 19 showing an example in which the second light splitting film 120 and the light modulation component 110 are formed as one body;

[0049] Figure 20 showing a schematic diagram of ghost image elimination;

[0050] Figure 21 showing a schematic diagram of an array of microstructure units in a light modulation component formed along a curved surface;

[0051] Figure 22 An example structure of a cylindrical rectangular grating is shown.

[0052] Figure 23 A schematic diagram showing the position of optional polarizer in an optical imaging assembly is shown.

[0053] Figure 24 A schematic diagram showing an optical imaging assembly 2400 according to an alternative embodiment of the present application is shown.

[0054] Figure 25 A schematic diagram showing an optical imaging assembly 2500 according to an alternative embodiment of the present application is shown.

[0055] Figure 26 A schematic diagram showing an optical imaging system when the light modulating component is integrated with the lens is shown.

[0056] Figure 27 A schematic diagram showing an optical imaging assembly 2700 according to an alternative embodiment of the present application is shown.

[0057] Figure 28 A schematic diagram showing an optical imaging assembly 2800 according to an alternative embodiment of the present application is shown.

[0058] Figure 29 A schematic diagram showing a one-dimensional grating transmissive array propagating light rays is shown.

[0059] Figure 30 A schematic diagram showing an optical imaging module 3000 according to an example embodiment of the present application is shown.

[0060] Figure 31 A schematic block diagram showing a floating display device 3100 that can implement floating image stitching according to an embodiment of the present application is shown.

[0061] Figure 32 A schematic diagram showing a multi-layer display device according to an embodiment of the present application is shown.

[0062] Figure 33 A schematic diagram showing a transparent display device implemented through micro-projection is shown.

[0063] Figure 34 A schematic diagram showing a multi-layer display device implementing naked-eye 3D display is shown.

[0064] Figures 35A-35C An illustrative schematic diagram showing a display module employing a three-dimensional display is shown. DETAILED DESCRIPTION

[0065] In the following detailed description of embodiments of the application, numerous specific details are set forth in order to provide a thorough understanding of the application. However, well-known methods, structures and techniques have not been described in detail in order to avoid obscuring the application. References to specific Recombinant DNA techniques are not intended to be limiting, but rather to illustrate an appropriate means by which to practice the present application. Unless otherwise specified, the description of an embodiment using terms such as "about" or "substantially" refers to an approximate value that can allow for a degree of error due to manufacturing tolerances, variations caused by the process in which it is created, variations in measurements of the physical properties from sample to sample, variations in the measurements of the physical properties by different testing equipment, and the like. Such terms should be interpreted in the context to which they are used. Unless otherwise specified, the description of an embodiment using terms such as "first" or "second" does not imply an order of priority or importance, but rather is used to distinguish one element from another. Unless otherwise specified, the description of an embodiment using terms such as "one," "another," or "an" does not imply that only a single element can be employed. The

[0066] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The materials, methods, and examples provided herein are illustrative only and not intended to be limiting. Except as otherwise indicated, the description of an embodiment using terms such as "first" or "second" does not imply an order or significance of importance, but rather is used to distinguish one element from another. The description of an embodiment using terms such as "one," "another," or "an" does not imply that only a single element can be employed. The description of an embodiment using terms such as "includes," "having," "contains" or "comprising" is used to indicate the inclusion of one or more elements, but not to the exclusion of other elements. The description of an embodiment using terms such as "connected" or "coupled" is used to indicate any connection or coupling, either direct or indirect, between or among two or more elements. The phrase "A and B are substantially equal" is intended to account for manufacturing tolerances, such that A and B can be within ±10% of each other. The phrase "X and Y are substantially orthogonal" is intended to account for manufacturing tolerances, such that the angle between X and Y can be between 80° and 100°.

[0067] In the present application, all embodiments and preferred embodiments mentioned herein can be combined with each other to form new technical solutions, unless otherwise specified. In the present application, all technical features and preferred features mentioned herein can be combined with each other to form new technical solutions, unless otherwise specified.

[0068] In the description of the embodiments of the present application, the term "and / or" is merely an association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are an "or" relationship.

[0069] Figure 1 A schematic diagram of an optical imaging assembly 100 according to some embodiments of the present application is shown. Referring to Figure 1 , the optical imaging assembly 100 according to embodiments of the present application can include a transparent light modulation component 110. The light modulation component 110 has a first surface 101 and a second surface 102 opposite to the first surface 101, and can include a light splitting layer 111 formed inside. The light splitting layer 111 has an array of microstructure units. Each microstructure unit in the array of microstructure units can be a dihedral element, which has two adjacent surfaces forming a right angle. Any light ray incident on the surface of the dihedral element, a part of the light ray is reflected according to the original angle, as Figure 2 shown. The dihedral element is formed with a first light splitting film on its surface. The array of microstructure units is used to back reflect the light ray in a first direction (for example, the x direction) to make the light ray return in the incident direction.

[0070] The optical imaging assembly 100 further includes a second light splitting film 120. The second light splitting film 120 can be arranged outside the first surface 101 of the light modulation component 110 (as Figure 1 shown). In the optical imaging assembly 100, the image light (for example, light emitted from the object plane 10) incident on one of the first surface 101 and the second surface 102 of the light modulation component 110 is modulated by the light splitting layer 111 and the second light splitting film 120 to be emitted from the other of the first surface 101 and the second surface 102. The light modulation can include back reflection by the light splitting layer 111 (in particular, the array of microstructure units therein), reflection by the second light splitting film 120, and transmission by the light splitting layer 111. In this way, the optical imaging assembly 100 can be used to form a suspended real image of an image in the air (for example, on the image plane 20), or can also be used in a head-mounted display device (HMD), for example, to replace the concave half-reflection half-transmission lens in a conventional see-through HMD. Due to the special properties of the optical imaging assembly, using the assembly does not introduce additional phase difference to the system, while the outside view can be observed through, and a larger field of view angle can be achieved than existing see-through head-mounted display devices.

[0071] Figure 3A schematic diagram of optical imaging assembly 300 according to some other embodiments of the present application is shown. In optical imaging assembly 300, the first light-splitting film on the microstructure units can be a light intensity splitting film (e.g., a 70% reflection and 30% transmission light-splitting film), while the second light-splitting film 120 can be a linearly polarized light-splitting film (e.g., transmitting p-polarized light and reflecting s-polarized light), with the polarization axis of the linearly polarized light-splitting film at an angle of 45 degrees or 135 degrees to the microstructure unit array (x-direction or y-direction). See Figure 3 The image light (divergent light) emitted from point o on the object plane can be linearly polarized light, with the polarization direction in the xy plane at an angle of 45 degrees to the x-axis, incident on the light-splitting layer 111 from the second surface 102 of the light modulation component 110. A portion of the light is back-reflected through the light-splitting layer 111 (specifically, the microstructure unit array therein) without participating in the final imaging (this portion of back-reflected light is not shown), and the imaging light transmitted through the light-splitting layer 111 is reflected by the second light-splitting film 120 (for transmitting p-polarized light and reflecting s-polarized light), with the polarization transmission axis of the second light-splitting film in the xy plane at an angle of -45 degrees to the x-axis, and the polarization reflection axis (absorption axis) of the second light-splitting film at an angle of 45 degrees to the x-axis. The polarized light reflected by the second light-splitting film is incident on the light-splitting layer 111 from the first surface 101 with the polarization direction at an angle of -45 degrees to the x-axis. A portion of the light is transmitted through the light-splitting layer 111 (specifically, the microstructure unit array therein) without participating in the final imaging (this portion of transmitted light is not shown), and another portion of the light is reflected by the light-splitting layer 111 twice, with the polarization direction of the first reflected light at an angle of 45 degrees to the x-axis, and the polarization direction of the second reflected light at an angle of -45 degrees to the x-axis. The polarization direction of the imaging light back-reflected from the light-splitting layer 111 is the same as the direction of the polarization transmission axis of the second light-splitting film 120, and thus the imaging light is transmitted by the second light-splitting film 120, converging at o' on the image plane 20.

[0072] Figure 4 A schematic diagram of optical imaging assembly 400 according to some other embodiments of the present application is shown. In optical imaging assembly 400, the second light-splitting film 120 can also be a circularly polarized light-splitting film, with circularly polarized dichroism, selectively transmitting or reflecting one of the two circularly polarized light components of opposite rotation in the light beam. For example, the circularly polarized light-splitting film can be a cholesteric liquid crystal film, with circularly polarized light of the same rotation as the liquid crystal being almost completely reflected, and circularly polarized light of opposite rotation being almost completely transmitted. As shown in FIG. 4, the circularly polarized light-splitting film 120 is arranged on the light-splitting layer 111, with the polarization transmission axis of the circularly polarized light-splitting film at an angle of 45 degrees to the microstructure unit array (x-direction or y-direction). Figure 4As shown, the image light (divergent light) emitted from point O on the object surface is right-handed polarized light. It is incident on the beam-splitting layer 111 from the second surface 102 of the light modulation component 110. A portion of the light is reflected back through the beam-splitting layer 111 (specifically, the microstructure unit array therein) and does not participate in the final imaging. The imaging light transmitted through the beam-splitting layer 111 is reflected by the second beam-splitting film 120 (used to transmit left-handed circularly polarized light and reflect right-handed circularly polarized light). The right-handed circularly polarized light reflected by the second beam-splitting film becomes left-handed circularly polarized light. It is incident on the beam-splitting layer 111 from the first surface 101. A portion of the light is transmitted through the beam-splitting layer 111 (specifically, the microstructure unit array therein) and does not participate in the final imaging. The other portion of the light is reflected twice by the beam-splitting layer 111. The polarization direction of the first reflected light is right-handed circularly polarized light, and the polarization direction of the second reflected light is left-handed circularly polarized light. The imaging light reflected back from the beam splitter 111 passes through the second beam splitter 120 and is then focused at point o' on the image plane 20.

[0073] Figure 5 A schematic diagram of an optical imaging assembly 500 according to other embodiments of the present invention is shown. The optical imaging assembly 500 according to embodiments of the present invention may include a transparent light modulation component 110. The light modulation component 110 has a first surface 101 and a second surface 102 opposite to the first surface 101, and may include a beam-splitting layer 111 formed therein. The beam-splitting layer 111 has an array of microstructure units. Each microstructure unit in the array of microstructure units may be a corner prism element having three mutually perpendicular adjacent surfaces, such as... Figure 6A As shown in Figure 6B, a first beam-splitting film is formed on a beam-splitting layer 111. An array of microstructure units is used to reflect the light back so that the light returns in the direction of incidence.

[0074] In the optical imaging assembly 500, the first beam splitter on the microstructure unit can be an intensity beam splitter (e.g., a 50% reflective and 50% transmittant beam splitter), while the second beam splitter 120 can be a linearly polarized beam splitter (e.g., transmitting p-polarized light and reflecting s-polarized light). The second beam splitter 120 can be disposed outside the first surface 101 of the optical modulation component 110. The optical imaging assembly 500 also includes a quarter-wave plate 130, disposed between the optical modulation component 110 and the second beam splitter 120, with the axial angle between the quarter-wave plate 130 and the linearly polarized beam splitter being 45 degrees or 135 degrees. Conversely, the quarter-wave plate 130 can also be a combination of a quarter-wave plate and a half-wave plate. Figure 5As shown, the image light (divergent light) emitted from the o point on the object plane 10 is left-handed circularly polarized light, which is incident on the light-splitting layer 111 from the second surface 102 of the light modulation component 110, a portion of the light is back-reflected via the light-splitting layer 111 (specifically, the microstructure unit array therein) without participating in the final imaging, and the imaging light transmitted through the light-splitting layer 111 is converted into s-polarized light by the 1 / 4 wave plate and is reflected by the second light-splitting film 120 (for transmitting p-polarized light and reflecting s-polarized light), again passes through the 1 / 4 wave plate and is converted into left-handed circularly polarized light, and is irradiated onto the corner cube prism. As shown, the direction of rotation of the circularly polarized light is changed once every time it is reflected, and becomes right-handed circularly polarized light after being reflected on the three surfaces of the corner cube prism, and the right-handed circularly polarized light is converted into p-polarized light by the 1 / 4 wave plate and is transmitted through the second light-splitting film to form a suspended real image of the image in the air (for example, on the image plane 20). Figure 7 As shown, the direction of rotation of the circularly polarized light is changed once every time it is reflected, and becomes right-handed circularly polarized light after being reflected on the three surfaces of the corner cube prism, and the right-handed circularly polarized light is converted into p-polarized light by the 1 / 4 wave plate and is transmitted through the second light-splitting film to form a suspended real image of the image in the air (for example, on the image plane 20).

[0075] Figure 8 A schematic diagram of an optical imaging assembly 800 according to another embodiment of the present application is shown. In the optical imaging assembly 800, the second light-splitting film 120 can also be a circularly polarized light-splitting film. The second light-splitting film 120 can be arranged outside the first surface 101 of the light modulation component 110. The 1 / 4 wave plate 130 has an axial direction of 0 degrees and is arranged between the light modulation component 110 and the second light-splitting film 120. As shown, Figure 8 As shown, the image light (divergent light) emitted from the o point on the object plane 10 is 45-degree linearly polarized light, which is incident on the light-splitting layer 111 from the second surface 102 of the light modulation component 110, a portion of the light is back-reflected via the light-splitting layer 111 (specifically, the microstructure unit array therein) without participating in the final imaging, and the imaging light transmitted through the light-splitting layer 111 is converted into right-handed circularly polarized light by the 1 / 4 wave plate and is reflected by the second light-splitting film 120 (for transmitting left-handed circularly polarized light and reflecting right-handed circularly polarized light), and becomes left-handed circularly polarized light after being reflected, and is converted into 45-degree linearly polarized light by the 1 / 4 wave plate and is irradiated onto the corner cube prism, the direction of polarization of the linearly polarized light is changed once every time it is reflected, and becomes -45-degree linearly polarized light after being reflected on the three surfaces of the corner cube prism, and the -45-degree linearly polarized light is converted into left-handed circularly polarized light by the 1 / 4 wave plate and is transmitted through the second light-splitting film 120 to form a suspended real image of the image in the air (for example, on the image plane 20).

[0076] Figure 9A schematic diagram of an optical imaging assembly 900 for floating display according to some embodiments of the present application is shown. The optical imaging assembly 900 can include a transparent light modulating component 110. The light modulating component 110 has a first surface 101 and a second surface 102 opposite to the first surface 101, and can include a light splitting layer 111 formed inside thereof. The light splitting layer 111 has an array of microstructure units. Each of the microstructure units in the array of microstructure units can have at least two surfaces perpendicular to each other (the microstructure can be a dihedral angle structure or a corner cube structure), and a first light splitting film formed thereon, which can be a polarization splitting film (e.g. transmits p-polarized light and reflects s-polarized light). The array of microstructure units is configured to retro-reflect light in at least a first direction (e.g. x-direction) to return the light in the incident direction.

[0077] The optical imaging assembly 900 further includes a second light splitting film 120 and a quarter wave plate 130. The second light splitting film 120 can be a light intensity splitting film (e.g. a 50% reflecting 50% transmitting light splitting film), and can be disposed outside the second surface 102 of the light modulating component 110. The quarter wave plate 130 is disposed between the light modulating component 110 and the second light splitting film 120. It is contemplated that the quarter wave plate 130 can also be a combination of a 1 / 4 wave plate + a 1 / 2 wave plate. The image light emitted from the o point on the object plane 10 is circularly polarized light, and is incident on the second light splitting film 120. A portion of the light is reflected by the second light splitting film 120 without participating in the final imaging, and the imaging light transmitted through the second light splitting film 120 is modulated by the quarter wave plate 130 into s-polarized image light, which is incident on the light splitting layer 111 from the second surface 102 of the light modulating component 110. The s-polarized image light is retro-reflected by the light splitting layer 111 (in particular, the array of microstructure units therein), and the retro-reflected s-polarized image light passes through the quarter wave plate 130 again and is split by the second light splitting film 120. A portion of the retro-reflected light is transmitted through the second light splitting film 120 without participating in the final imaging, and another portion of the imaging light reflected from the second light splitting film 120 is modulated by the quarter wave plate 130 into p-polarized light again, which is transmitted by the light splitting layer 111, and thus converges at the o' point on the image plane 20.

[0078] Figure 10A schematic diagram of an optical imaging assembly 1000 for floating display according to some other embodiments of the present application is shown. The optical imaging assembly 1000 can include a transparent light modulating component 110. The light modulating component 110 has a first surface 101 and a second surface 102 opposite to the first surface 101, and can include a light splitting layer 111 formed inside. The light splitting layer 111 has an array of microstructure units. Each of the microstructure units in the array can be a dihedral element having two adjacent surfaces forming a right angle, and any light ray impinging on the surface of the dihedral element, a portion of the light ray is reflected according to the original angle and a first light splitting film is formed thereon. The optical imaging assembly 1000 further includes a second light splitting film 120 and a quarter wave plate 130. The first light splitting layer 111 can be coated with a light intensity splitting film (e.g. a 50% reflection and 50% transmission light splitting film), and the second light splitting film 120 can be a circular polarization splitting film and is arranged outside the second surface 102 of the light modulating component 110. The quarter wave plate 130 is arranged between the light modulating component 110 and the second light splitting film 120, and the axial direction of the quarter wave plate is at an angle of 45° with the horizontal direction. As shown in Figure 10 the image light (divergent light) emitted from the point o on the object plane 10 is linearly polarized light with the polarization axis in the horizontal direction, and is incident on the light splitting layer 111 from the second surface 102 of the light modulating component 110. A portion of the light is back-reflected by the light splitting layer 111 (specifically, the array of microstructure units therein) without participating in the final imaging, and the imaging light transmitted through the light splitting layer 111 is converted into left-handed circularly polarized light by the quarter wave plate, and is reflected by the second light splitting film 120 (which is configured to reflect left-handed circularly polarized light and transmit right-handed circularly polarized light). The left-handed circularly polarized light reflected by the second light splitting film 120 has its polarization direction changed to right-handed circularly polarized light, and is converted into linearly polarized light with the polarization axis in the horizontal direction by the quarter wave plate 130, and is incident on the light splitting layer 111 from the first surface 101. A portion of the light is transmitted through the light splitting layer 111 (specifically, the array of microstructure units therein) without participating in the final imaging, and another portion of the light is reflected by the light splitting layer 111 twice, and the polarization direction of the light ray is linearly polarized light with the polarization axis in the horizontal direction each time. The imaging light back-reflected from the light splitting layer 111 is converted into right-handed circularly polarized light by the quarter wave plate 130 again, and is transmitted through the second light splitting film 120 to exit, and is thus converged at the point o' on the image plane 20.

[0079] Figure 11A schematic diagram of an optical imaging assembly 1100 for floating display according to some other embodiments of the present application is shown. The optical imaging assembly 1100 can include a transparent light modulating component 110. The light modulating component 110 has a first surface 101 and a second surface 102 opposite to the first surface 101, and can include a light splitting layer 111 formed inside. The light splitting layer 111 has an array of microstructure units. Each of the microstructure units in the array can be a dihedral element having two adjacent surfaces forming a right angle, and any light ray impinging on the dihedral element surface, a portion of the light ray is reflected according to the original angle and a first light splitting film is formed thereon. The optical imaging assembly 1100 further includes a second light splitting film 120 and a half wave plate 130. The first light splitting layer 111 is coated with a light intensity splitting film (e.g. a 50% reflection and 50% transmission splitting film), and the second light splitting film 120 is a linearly polarized light splitting film (transmits p light and reflects s light) and can be arranged outside the second surface 102 of the light modulating component 110. The half wave plate 130 is arranged between the light modulating component 110 and the second light splitting film 120, and the axial direction of the half wave plate forms an angle of 22.5° or 67.5° with the horizontal direction. As shown in Figure 11 the image light (divergent light) emitted from the o point on the object plane 10 is linearly polarized light of 45°, and is incident on the light splitting layer 111 from the second surface 102 of the light modulating component 110. A portion of the light is back-reflected via the light splitting layer 111 (specifically, the array of microstructure units therein) and does not participate in the final imaging, and the imaging light transmitted through the light splitting layer 111 is converted to s polarized light by the half wave plate and is reflected by the second light splitting film 120. After passing through the half wave plate 130, the light reflected by the second light splitting film is converted to linearly polarized light of -45°, and is incident on the light splitting layer 111 from the first surface 101. A portion of the light is transmitted via the light splitting layer 111 (specifically, the array of microstructure units therein) and does not participate in the final imaging, and another portion of the light is reflected twice by the right-angle grating of the light splitting layer 111. The first reflected light is linearly polarized light of 45°, and the second reflected light is converted to linearly polarized light of -45°. After passing through the half wave plate 130 again, the imaging light back-reflected from the light splitting layer 111 is converted to p polarized light and is transmitted through the second light splitting film 120, thereby converging at o' on the image plane 20.

[0080] It can be understood that, since the microstructure unit array of the light splitting layer 111 is a conjugate imaging unit, the object plane 10 and the image plane 20 of the above various optical imaging assemblies can be arranged substantially symmetrically relative to the light splitting layer 111. The benefit of using a conjugate imaging element is that the positional relationship (object and image) is conjugate, the image is not magnified, and there is no aberration. In addition, since the optical path is reversible, the positions of the object plane 10 and the image plane 20 shown in the above embodiments can also be interchanged; that is, the optical imaging assembly 100, 300, 400, 500, 800, 900, 1000, or 1100 of the present application can be used for levitation imaging in both positive (the second surface 102 enters light and the first surface 101 exits light) and negative (the first surface 101 enters light and the second surface 102 exits light) modes.

[0081] In some embodiments of the present application, the polarization splitting film can be a DBEF structure, as shown in Figure 12 Alternatively, the polarization splitting film can be a metal wire grating; or, the polarization splitting film can also be formed by a multilayer dielectric coating. Alternatively, the polarization splitting film can be a cholesteric liquid crystal circular polarization splitting film, as shown in Figure 13 These film layers can be flat plate structures, or can be made on a microstructure.

[0082] As shown in Figure 14 The light splitting layer 111 divides the light modulating component 110 into a first medium portion and a second medium portion. The first medium portion has a refractive index n1, and the second medium portion has a refractive index n2. Preferably, the refractive index n1 of the first medium portion is equal to the refractive index n2 of the second medium portion, so that the light rays of different angles do not refract when passing through the microstructure, and a single levitation image with good quality can be formed. If the refractive indices are not the same (for example, n1 > n2, as shown in Figure 4 When the imaging light passes through the right-angle microstructure array, it will diverge or converge, resulting in the formation of multiple images (at least two), which affects the imaging quality.

[0083] In preferred embodiments of the present application, the refractive indices of the first medium portion and the second medium portion can be between 1.3 and 1.8, i.e. 1.3 ≤ n1 = n2 ≤ 1.8.

[0084] In preferred embodiments of the present application, the first medium portion and the second medium portion of the light modulating component 110 can be formed of isotropic materials, thereby avoiding birefringence.

[0085] In a preferred embodiment of the present application, the optical imaging assembly 100 can include a transparent light modulating component 110. The light modulating component 110 has a first surface 101 and a second surface 102 opposite to the first surface 101, and can include a light splitting layer 111 formed inside. The light splitting layer 111 has an array of microstructure units. Each microstructure unit in the array of microstructure units can be a dihedral element having two adjacent surfaces forming a right angle, and any light ray impinging on the surface of the dihedral element is partially reflected according to the original angle and a first light splitting film is formed thereon. The array of microstructure units is used to retro-reflect the light ray in a first direction (e.g., x direction) so that the light ray returns in the direction of incidence.

[0086] Preferably, the first light splitting film can be a depolarization light intensity splitting film, and the p light and s light have substantially the same reflectivity. Preferably, |Rs-Rp| < 10%. This ensures that the polarization state of the light ray does not change as much as possible when the light ray is transmitted inside the light modulating component, e.g., the left circularly polarized light is still left circularly polarized light when it is transmitted, instead of becoming elliptically polarized light. In this structure, there are mainly two paths of ghost images, as shown in Figure 15 The first path is that the incident light ray is reflected by the polarization light splitting film and impinges on the light splitting layer of the right-angle grating microstructure, the light ray reflected by the right-angle grating once is reflected by the polarization light splitting film (the normal imaging light path is reflected by the right-angle grating twice, and the light ray is retro-reflected according to the original path), and the reflected light is emitted after one or more times of reflection on the right-angle microstructure to form a ghost image / stray light. The second path of the ghost image is that the light emitted from the object point impinges on the right-angle grating microstructure, and the light ray is not directly transmitted but is reflected by one of the facets of the right-angle grating (because the first light splitting film is partially transmissive and partially reflective), the light reflected by the right-angle grating impinges on the polarization light splitting film and is reflected, and the reflected light is emitted after one or more times of reflection on the right-angle microstructure to form a ghost image / stray light.

[0087] When there is an air layer between the light modulating component 110 and the second light splitting film 120, the incident light ray is reflected by the polarization light splitting film and impinges on the light splitting layer of the right-angle grating microstructure, the light ray reflected by the right-angle grating once is totally reflected by the first surface 101 of the light modulating component 110 (because the angle of the light ray reflected once is > 45°), as shown in Figure 16The other ghost image path, i.e. the light from the object point is incident on the microstructure of the right-angle grating, the light is not directly transmitted but is specularly reflected by one face of the right-angle grating, the light reflected by the right-angle grating is also totally reflected (because the angle of the light reflected by the right-angle grating is >45°) when it is incident on the first surface of the light modulation component. The light totally reflected by the first surface of the light modulation component in the above two paths is again incident on the right-angle microstructure and exits after one or more reflections to form the ghost image / stray light. Therefore, in the preferred embodiment of the present application, there is substantially no gap (air layer) between the light modulation component 110 and the second light splitting film 120, for example, they can be glued together as one.

[0088] In addition, a variety of media (e.g. lenses, adhesives, etc.) can be allowed to exist between the light modulation component 110 and the second light splitting film 120, the refractive indices of these media can be substantially equal and the difference between the refractive indices of the first medium portion and the second medium portion is less than 0.3, which helps to reduce stray light and ghost images.

[0089] Optionally, the optical imaging assembly according to the embodiments of the present application can also include a light filtering element for passing light rays within a predetermined angular range. The light filtering element can be a micro-courver structure or can be implemented by coating. An example of a micro-courver structure is shown in Figure 17 which can be used to pass light rays within a certain angle, preferably within a range of ±45 degrees, and absorb light rays with a large angle, so that normal display light rays can pass, and for the two stray light / ghost light paths described above, because the angle is large, they are absorbed, thereby achieving the effect of eliminating ghost images. In addition, by setting the light passing range within ±45°, while ensuring an observable angle range of >90 degrees, the optical system has higher optical efficiency.

[0090] Preferably, the light filtering element (e.g. light control film) is placed between the second light splitting film (e.g. polarization light splitting film) and the first light splitting film (e.g. energy light splitting film), as shown in Figure 18 .

[0091] In some embodiments of the present application, the second light splitting film 120 is arranged on the first surface 101 of the light modulation component 110, and the second light splitting film 120 is in close contact with the first surface 101 without air gap. Alternatively, the second light splitting film 120 can be formed integrally with the light modulation component 110 as a single component. As shown in Figure 19 the second light splitting film 120 can be arranged between the first surface 101 of the light modulation component 110 and the light splitting layer 111. Those skilled in the art can understand that in some embodiments, the second light splitting film 120 can also be arranged between the second surface 102 of the light modulation component 110 and the light splitting layer 111.

[0092] Whether the second light splitting film 120 is formed integrally with the light modulating component 110 or not, the distance d between the second light splitting film 120 and the light splitting layer 111 (e.g. the tooth peak of the microstructure unit) is preferably between 0-100 μm. The ghost light rays reflected by the first surface 101 after being reflected by the first surface 101 again and then by the second surface 102 of the light modulating component 110, and then by the light splitting layer 111 again, can be controlled within the range of 1-2 pitches of the straight grating structure in the horizontal direction by reducing the distance d. Thus, even if the ghost light rays exit, they coincide with the normal imaging, as shown in FIG. 8, thereby achieving the purpose of eliminating the ghost. Figure 20

[0093] In some embodiments of the present application, the array of microstructure units in the light modulating component 110 can be formed in a plane, or can be formed in a curved surface, as shown in FIG. 9. For example, in the case of a dihedral element as the microstructure unit, the array of microstructure units can be formed as a cylindrical straight grating structure, which is curved in the y direction and is a one-dimensional straight grating structure in the x direction, as shown in FIG. 10. Figure 21 Figure 22

[0094] Optionally, in some embodiments, the optical imaging assembly 100, 300, 400, 500, 800, 900, 1000 or 1100 can further include a polarizer, or can include a combination of a polarizer and a phase retarder, for eliminating the light rays reflected back from the light splitting film. As shown in FIG. 11, in the optical imaging assembly 100, the polarizer can be arranged outside the second surface of the light modulating component. Figure 23

[0095] Figure 24 and Figure 25 FIGS. 24 and 25 show schematic diagrams of optical imaging assemblies 2400 and 2500 for floating display according to optional embodiments of the present application. Many details of the optical imaging assemblies 2400 and 2500 are the same as those of the optical imaging assemblies 100, 300, 400, 500, 800, 900, 1000 or 1100 described above with respect to FIGS. 1-23, and will not be repeated here. The optical imaging assembly 2400 can include a polarizer 140. The polarizer 140 can be arranged outside the second surface 102 of the light modulating component 110, the light splitting layer 111 in the optical imaging assembly 2400 is a dihedral micro-prism array structure, and the first light splitting film 110 is a light intensity splitting film. The optical imaging assembly 2500 can include a polarizer 140 and a second quarter-wave plate 150. The polarizer 140 can be arranged outside the second surface 102 of the light modulating component 110, and the second quarter-wave plate 150 can be arranged between the light modulating component 110 and the polarizer 140. The light splitting layer 111 in the optical imaging assembly 2500 is an angle corner micro-prism array structure, and the first light splitting film 110 is a polarization splitting film. Figure 1

[0096] ​​​​​In the optical imaging assembly 2400, the incident light becomes p-polarized light after passing through the polarizer 140, and is incident on the light splitting layer 111 from the second surface 102 of the light modulation component 110 with an angle of 45 degrees with respect to the x-axis. The imaging light transmitted through the light splitting layer 111 is reflected by the second light splitting film 120 (for transmitting p-polarized light and reflecting s-polarized light), the polarization transmission axis of the second light splitting film is in the xy plane with an angle of -45 degrees with respect to the x-axis, and the polarization reflection axis (absorption axis) of the second light splitting film is at an angle of 45 degrees with respect to the x-axis. The polarized light reflected by the second light splitting film is incident on the light splitting layer 111 from the first surface 101 with an angle of -45 degrees with respect to the x-axis, a part of the light is transmitted through the light splitting layer 111 (specifically, the microstructure unit array therein) and then absorbed by the polarizer 140, and does not participate in imaging, so as to achieve the purpose of eliminating stray light. Another part of the light is reflected twice by the light splitting layer 111, the polarization direction of the first reflected light becomes 45 degrees with respect to the x-axis, and the polarization direction of the second reflected light becomes -45 degrees with respect to the x-axis. The polarization direction of the imaging light reflected from the light splitting layer 111 is the same as the direction of the polarization transmission axis of the second light splitting film 120, so the imaging light is transmitted by the second light splitting film 120, and is converged at o' on the image plane 20.

[0097] In the optical imaging assembly 2500, the incident light becomes p-polarized light after passing through the polarizer 140, and becomes circularly polarized light after passing through the second quarter-wave plate 150. The light is split by the light intensity splitting film 120, a part of the light becomes s-polarized light after passing through the first quarter-wave plate 130, is reflected by the polarization splitting layer 111, and is then reflected by the microstructure array. The light returns along the original path, and is converted into p-polarized light due to twice passing through the first quarter-wave plate 130, and is emitted through the polarization splitting film 111, so that the light emitted by the object point o is converged on the other side of the system to form the image point o'. In particular, the light returned by the light intensity splitting film passes through the second quarter-wave plate 150 again, and is converted into s-polarized light, which is absorbed by the polarizer 140, so as to achieve the purpose of eliminating stray light.

[0098] Optionally, in some embodiments, the optical imaging assembly 2400 or 2500 can further include an additional polarizer for absorbing non-imaging light transmitted through the polarization splitting film and reducing the reflection of ambient light (non-imaging light) by the polarization splitting film. For example, in the optical imaging assembly 2400, the additional polarizer 160 can be arranged outside the second light splitting film 120.

[0099] Optionally, in some embodiments, the light modulating component 110 can be configured to image in only a first direction (e.g., to converge light emanating from an object point o at o' in the x direction), in which case the optical imaging assembly 100, 300, 400, 500, 800, 900, 1000, 1100, 2400, or 2500 can further comprise an imaging light group for imaging in a second direction (e.g., to converge light emanating from an object point o at o' in the y direction), wherein the first and second directions are orthogonal to the optical axis of the optical imaging assembly. For example, the imaging light group can comprise one or more lenses and aperture stops. In particular, the image-side numerical aperture of the imaging light group in the first direction is preferably larger than the image-side numerical aperture of the imaging light group in the second direction.

[0100] Optionally, in some embodiments, the light modulating component 110 in the optical imaging assembly 100, 300, 400, 500, 800, 900, 1000, 1100, 2400, or 2500 can be formed as a single component with an additional lens 210, i.e., a "lens & grating" structure, such as by injection molding the microstructured light splitting layer and the lens as one piece, or can be glued with the additional lens 210 to form an integrated structure, as shown. Figure 26 The lens 210 can be configured to modulate the imaging light in a second direction to assist imaging or to optimize imaging quality. The second direction can be substantially orthogonal to the first direction.

[0101] Figure 27 A schematic diagram of an optical imaging assembly 2700 according to an optional embodiment of the present application is shown. The optical imaging assembly 2700 can comprise any of the optical imaging assemblies 100, 300, 400, 500, 800, 900, 1000, 1100, 2400, or 2500 as described above. Figure 27 The optical imaging assembly 2700 can be configured to image in only a first direction (e.g., to converge light emanating from an object point o at o' in the x direction), in which case the optical imaging assembly 2700 can further comprise an imaging light group for imaging in a second direction (e.g., to converge light emanating from an object point o at o' in the y direction), wherein the first and second directions are orthogonal to the optical axis of the optical imaging assembly. Figure 1The optical imaging assembly 2700 can further include a first lens 2710, a second lens 2720, a third lens 2730, and a fourth lens 2740. A first polarizer (not shown) can be disposed outside the second surface 102 of the light modulating component 110. In this example, the light modulating component 110 in the optical imaging assembly 100 can be used to modulate the imaging light in the x direction for imaging, while the first, second, third, and fourth lenses can be used to modulate the imaging light in the y direction for imaging, where the first lens 2710 is the aperture stop of the optical system in the y direction. Optionally, the first lens 2710 can be a Fresnel lens, and the Fresnel lens teeth are equidistantly spaced to facilitate seamless stitching (as described below). As described above, the imaging of the floating image can be achieved with only the light modulating component 110, but as the viewing position moves in the y direction, the floating image moves in the y direction, so the combination of the first, second, third, and fourth lenses 2710, 2720, 2730, and 2740 can be used to adjust the y direction to solve the positioning problem of the floating image in the y direction in space, so that a larger field of view angle can be achieved in the horizontal direction. The optical imaging assembly 2700 can further include a second polarizer disposed between the polarization beamsplitter film (e.g., the second beamsplitter film 120, not shown in FIG. 2) and the image plane, to reduce the reflection of the external scene light (non-imaging light) by the polarization beamsplitter film. In this way, the image light on the object plane 10 can form a floating image on the image plane 20 via the example optical imaging assembly 2700. Figure 27

[0102] Optionally, in some embodiments, the optical imaging assemblies 100, 300, 400, 500, 800, 900, 1000, 1100, 2400, 2500, 2600, and 2700 can further include a one-dimensional grating array panel for imaging in the second direction. Figure 28 A schematic diagram of an optical imaging assembly 2800 according to an optional embodiment of the present application is shown. The optical imaging assembly 2800 can include any of the optical imaging assemblies described above (e.g., can include the polarizer 140, the light modulating component 110, the second beamsplitter film 120, and the second polarizer 160). The array of microstructure units in the light modulating component 110 in the optical imaging assembly 2800 is an array of dihedral angle elements in the x direction, i.e., the x direction is the structure of a one-dimensional square grating array. The optical imaging assembly 2800 can further include a panel of a one-dimensional grating transmission array 310 in the y direction. The one-dimensional grating transmission array structure can be formed by several parallel glass panels that are bonded together, with the bonding surfaces coated with a metal reflective film. As described above, the imaging of the floating image can be achieved with only the light modulating component 110, but as the viewing position moves in the y direction, the floating image moves in the y direction, so the combination of the one-dimensional grating transmission array 310 and the light modulating component 110 can be used to adjust the y direction to solve the positioning problem of the floating image in the y direction in space, so that a larger field of view angle can be achieved in the horizontal direction. Figure 29 ​As shown, the object point o is optically conjugated with the image point o', the object plane and the image plane of the structure are equal in size, and there is no aberration. In the prior art, a scheme for forming a floating image by using two one-dimensional grating transmission arrays orthogonal to each other is proposed. Compared with the prior art, the structure of the example optical imaging assembly 2800 has the advantages of low cost and few ghost images.

[0103] According to the example embodiments of the present application, an optical imaging module for floating display is also provided. Figure 30 A schematic diagram of an optical imaging module 3000 according to the example embodiments of the present application is shown. The optical imaging module 3000 includes two optical imaging assemblies described above and an additional polarizer 160, wherein one optical imaging assembly may, for example, include the polarizer 140, the light modulation component 110 and the second light splitting film 120, and the other optical imaging assembly may, for example, include the polarizer 140', the light modulation component 110' and the second light splitting film 120'. The first array of microstructure units in the light modulation component 110 of the first optical imaging assembly is arranged substantially orthogonally with respect to the second array of microstructure units in the light modulation component 110' of the second optical imaging assembly, and each of the first and second microstructure units is a dihedral element, i.e., a one-dimensional right-angle grating array. The first optical imaging assembly can be used to modulate the imaging light at the object point o in a first direction (e.g., the x direction), and the second optical imaging assembly can be used to modulate the imaging light at the object point o in a second direction (e.g., the y direction), and finally converge in the air to form a floating image point o'. According to yet other embodiments of the present application, a floating display device is also provided, which includes one or more optical imaging assemblies and / or optical imaging modules as described above; and an image display unit configured to emit image light. The image display unit presents an original image on the object plane of the optical imaging assembly and / or optical imaging module by direct display or indirect projection, and the image light then forms a floating image in the air through the optical system. If a large-size floating display is to be achieved, larger optical elements need to be processed, which results in a rapid increase in processing cost and a decrease in the precision of the optical elements. Therefore, the present application allows to provide a floating display device of variable size, which includes one or more image display units and one or more optical imaging assemblies and / or optical imaging modules, forms a plurality of floating sub-images in space, and the plurality of floating sub-images are spliced to form a complete floating image. This technical solution can achieve seamless splicing of the floating image while having lower manufacturing cost and making the floating display device more compact.

[0104] Figure 31 A schematic block diagram of a floating display device 3100 according to an embodiment of the present application, which can achieve splicing of a floating image, is shown. Referring to Figure 31According to an embodiment of the present application, the floating display device 3100 can include a display module 3110 and a plurality of optical imaging modules 3120 1～n The optical imaging modules 3120 i may be composed of the optical imaging assembly described above, or can be the optical imaging module 3000. The display module 3110 can be configured to emit display light constituting a target image. The plurality of optical imaging modules 3120 1～n may be configured to receive the display light emitted from the display module 3110 to form a floating image in the air. Each optical imaging module 3120 i defines an object plane 10 and an image plane 20. The display module 3110 (in particular, a display surface thereof) is arranged at the object plane 10 of the plurality of optical imaging modules. The light rays emitted by the pixel points on the display module 3110 can converge on the image plane 20 through one or more optical imaging modules in the plurality of optical imaging modules 3120 1～n .

[0105] In an embodiment of the present application, the display module 3110 can be composed of a plurality of display units spliced together or be a single display device, which can be a single complete display area or have a plurality of independent display areas. Thus, the display module 3110 can include a plurality of display portions arranged along the y direction. Each display portion can be configured to display a corresponding part of the target image. The target image displayed on the display module 3110 and the floating image presented at the floating image plane (i.e., the image plane 20) of the plurality of optical imaging modules 3120 1～n may be in an inverted imaging relationship in the y direction.

[0106] According to another exemplary embodiment of the present application, a multi-layer display device is also provided.

[0107] Figure 32 A schematic diagram of a multi-layer display device 3200 according to an embodiment of the present application is shown.

[0108] The multi-layer display device 3200 can include the floating display device 3100 described above and a transparent display device 200. The transparent display device 200 can be disposed at the light exit side (optically downstream) of the floating display device 3100. The display surface of the transparent display device 200 is located at a different position from the floating image plane 20 of the floating display device 3100, specifically between the floating image plane 20 and the floating display device 3100. The transparent display component 200 can have a high transmittance, such as a transparent OLED / LED / LCD display or a film (slide). The transparent display device 200 can also obtain an image projected by a micro projector by disposing a transparent film (film haze less than <5%) in front of the floating display device 3100, as shown in Figure 33Alternatively, the transparent film can be angle selective to light, scattering light at large angles (projected image) and transmitting light at small angles (hovering image).

[0109] The multi-layer display device 3200 according to the exemplary embodiment of the present application is described above. The multi-layer display device 3200 has a display surface 1 and a display surface 2, the hovering display device 3100 can form a hovering image at the display surface 1 (image plane 20), and the transparent display device 200 can display different information at the display surface 2. In this way, secondary information can be displayed on the display surface 2, and important information can be presented at the display surface 1, thereby improving the efficiency and experience of people obtaining information. Alternatively, images of the same size can be displayed on the display surface 1 and the display surface 2, and the observer can perceive the difference in darkness and color due to the distance between the objects and the observer, and thus the images of the objects in front and behind can be overlapped to generate a stereoscopic effect, thereby realizing naked-eye 3D display, as shown in Figure 34 .

[0110] Alternatively, the display module 3110 can also be a naked-eye 3D display, which can be a multi-view autostereoscopic display or a light field display. As shown in Figure 35A , a conventional naked-eye 3D display is composed of a flat panel display and a micro-optical unit, which can be a microlens or a slit grating. The flat panel display generates parallax images, which are sent to the left and right eyes of the observer after passing through the micro-optical unit, and the stereoscopic effect is generated by the binocular parallax effect of the human eye. As shown in Figure 35B , the point a1 on the display module 3110 enters the right eye, and the point a2 enters the left eye, and the point a perceived by the human eye due to the binocular parallax principle is in front of the screen. The point b1 on the display screen enters the right eye, and the point b2 enters the left eye, and the point b perceived by the human eye due to the binocular parallax principle is behind the screen. The left and right eyes together perceive the point c on the screen, and thus the position of the point c is perceived to be on the screen. Thus, the 3D image presented by the conventional naked-eye 3D display is centered on the screen as the depth center, and the 3D image within a certain depth range in front and behind the screen. Because the human eye focuses on the physical screen of the three-dimensional display when viewing, the floating three-dimensional image in space cannot be perceived, which affects the experience.

[0111] The display module 3110 in the present application can adopt a multi-view / light field display, which can well solve the problem. The screen plane of the multi-view / light field display is projected into space by the optical imaging module 3120 of the present application to form a hovering image plane, and by displaying parallax images on the multi-view / light field display, a 3D image within a certain range in front and behind the hovering image plane as the depth center can be formed in space. As shown in Figure 35CAs shown, in the floating image plane, point a is in the foreground depth plane, point b is in the background depth plane, and point c is in the floating image plane of the display device, and thus the 3D image formed is completely floating in the air, and has a better 3D effect experience.

[0112] The optical imaging assembly, the optical imaging module, the floating display device, and the multi-layer display device according to the exemplary embodiments of the present application are described in detail above. The present application has the following advantages: 1) the optical imaging assembly / module has a simple structure, is easy to process, and can effectively reduce the cost; 2) the optical imaging assembly / module can be a non-aberration system, and does not need to correct optical aberration, and has a large field of view angle; 3) various sizes of display modules (or a specific number of display units) and a specific number of optical imaging assemblies / modules can be used to realize different sizes of floating display, that is, the display modules can be used immediately after being spliced, and this is particularly advantageous for realizing large-size floating display; 4) the optical imaging assembly / module is designed once, and a corresponding number of the same optical imaging modules are used for seamless splicing of the floating image according to the required size of the floating image, and thus there is no need to design different optical imaging assemblies / modules for different sizes of floating image; and 5) there are fewer ghost images. The optical imaging assembly / module is used to realize light field reconstruction of image light in the air, and is a light field three-dimensional display technology. The image light is imaged along the x direction through the optical imaging assembly / module, and the image-side aperture angle is relatively large, and the binocular parallax condition is met, and thus the floating display of the image can be realized.

[0113] It should be understood that the above description is illustrative and not restrictive. For example, the above-described embodiments (and / or aspects thereof) can be used in combination with each other. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the various embodiments of the present application without departing from the scope thereof. While materials described herein are described as being used in one or more embodiments, such materials are not intended to limit the embodiments of the application which can be implemented using other equivalent- materials as would be known to one of ordinary skill in the art. The various embodiments of the present application are not to be limited in terms of the particular materials described herein which are meant to be illustrative only and do not limit the scope of the application as set forth in the claims. The scope of the present application is defined by the claims appended hereto, rather than the description appearing in the specification.

Claims

1. An optical imaging module for levitation displays, characterized in that, The optical imaging module includes: A first optical imaging component for modulating imaging light in a first direction; and The second optical imaging component is used to modulate the imaging light in the second direction. Each of the first optical imaging component and the second optical imaging component includes: A transparent light modulation component has a first surface and a second surface opposite to the first surface; A beam-splitting layer is formed within the light modulation component. The beam-splitting layer has an array of microstructured units, each microstructured unit having at least two surfaces perpendicular to each other and on which a first beam-splitting film is formed. The microstructured unit array is used to reflect light back in the first direction or the second direction so that the light returns in the incident direction. Second beam-splitting film; Image light incident on one of the first and second surfaces of the light modulation component is modulated by the beam-splitting layer and the second beam-splitting film and exits from the other of the first and second surfaces. The light modulation includes backscattering by the microstructure unit array, reflection by the second beam-splitting film, and transmission by the microstructure unit array. The microstructure units in the first optical imaging component and the second optical imaging component are dihedral elements, and the array of microstructure units in the first optical imaging component is substantially orthogonal to the array of microstructure units in the second optical imaging component.

2. The optical imaging module as described in claim 1, characterized in that, One of the first beam splitter and the second beam splitter is a polarization beam splitter, and the other is an intensity beam splitter.

3. The optical imaging module as described in claim 2, characterized in that, The polarization axis of the polarization beam splitter is set at an angle of 45 degrees or 135 degrees to the first direction or the second direction.

4. The optical imaging module as described in claim 1, characterized in that, The optical imaging assembly further includes a phase retardation plate disposed between the optical modulation component and the second beam splitter.

5. The optical imaging module as described in claim 4, wherein the phase delay plate is a quarter-wave plate.

6. The optical imaging module as described in claim 2, characterized in that, The second beam splitter is a polarizing beam splitter, and is disposed outside the first surface of the optical modulation component or between the first surface of the optical modulation component and the beam splitter layer.

7. The optical imaging module as described in claim 2, characterized in that, The first beam splitter is a polarizing beam splitter, and the second beam splitter is disposed outside the second surface of the optical modulation component or between the second surface of the optical modulation component and the beam splitter layer.

8. The optical imaging module as described in claim 2, characterized in that, The optical imaging assembly further includes a polarizer or a combination of a polarizer and a phase retarder, disposed on the outer side of the second surface of the optical modulation component.

9. The optical imaging module as described in claim 2, characterized in that, The optical imaging component further includes a linear polarizer or a circular polarizer, used to reduce the reflection of ambient light by the polarizing beam splitter.

10. The optical imaging module as claimed in claim 1, characterized in that, The beam-splitting layer divides the optical modulation component into a first medium portion and a second medium portion, wherein the first medium portion and the second medium portion have the same refractive index.

11. The optical imaging module as described in claim 10, characterized in that, The refractive indices of the first medium portion and the second medium portion are between 1.3 and 1.

8.

12. The optical imaging module as described in claim 10, characterized in that, There are multiple media between the optical modulation component and the second beam splitter, and the difference between the refractive index of the multiple media and the refractive index of the first medium portion and the second medium portion is less than 0.

3.

13. The optical imaging module as described in claim 10, characterized in that, The first medium portion and the second medium portion are formed of isotropic materials.

14. The optical imaging module as described in claim 1, characterized in that, The microstructure unit array is formed along a plane or curved surface.

15. The optical imaging module as claimed in claim 1, characterized in that, The object plane and image plane of the optical imaging component are arranged in a basically symmetrical manner with respect to the beam splitter.

16. The optical imaging module as described in claim 2, characterized in that, The light intensity splitter is a depolarized light intensity splitter.

17. An optical imaging component, characterized in that, The optical imaging component includes: A transparent light modulation component has a first surface and a second surface opposite to the first surface; A beam-splitting layer is formed within the light modulation component. The beam-splitting layer has an array of microstructured units, each microstructured unit having at least two surfaces perpendicular to each other and on which a first beam-splitting film is formed. The microstructured unit array is used to retroreflect light in at least a first direction so that the light returns in the incident direction. Second beam-splitting film; Image light incident on one of the first and second surfaces of the light modulation component is light modulated by the beam splitting layer and the second beam splitting film and exits from the other of the first and second surfaces. The light modulation includes back reflection by the microstructure unit array, reflection by the second beam splitting film, and transmission by the microstructure unit array. The light modulation component is used to perform imaging in the first direction, and the optical imaging assembly further includes an imaging light group for imaging in the second direction, wherein the first direction and the second direction are respectively orthogonal to the optical axis of the optical imaging assembly.

18. The optical imaging assembly as claimed in claim 17, characterized in that, The microstructure unit array is a one-dimensional right-angle grating array, and the light modulation component is integrated with the lens. The lens is used to modulate the imaging light in a second direction.

19. The optical imaging assembly as claimed in claim 17, characterized in that, The imaging optical group includes one or more lenses.

20. The optical imaging assembly as claimed in claim 19, characterized in that, One of the one or more lenses serves as the second-direction aperture stop of the optical imaging assembly in the second direction.

21. The optical imaging assembly as claimed in claim 20, characterized in that, The lens is a Fresnel lens, and the teeth of the Fresnel lens are set at equal intervals.

22. An optical imaging component, characterized in that, The optical imaging component includes: A transparent light modulation component has a first surface and a second surface opposite to the first surface; A beam-splitting layer is formed within the light modulation component. The beam-splitting layer has an array of microstructured units, each microstructured unit having at least two surfaces perpendicular to each other and on which a first beam-splitting film is formed. The microstructured unit array is used to retroreflect light in at least a first direction so that the light returns in the incident direction. Second beam-splitting film; Image light incident on one of the first and second surfaces of the light modulation component is light modulated by the beam splitting layer and the second beam splitting film and exits from the other of the first and second surfaces. The light modulation includes back reflection by the microstructure unit array, reflection by the second beam splitting film, and transmission by the microstructure unit array. The optical imaging component may further include a one-dimensional grating transmission array, wherein the microstructure unit array is a one-dimensional right-angle grating array, and the one-dimensional grating transmission array is substantially orthogonal to the one-dimensional right-angle grating array.

23. The optical imaging module as claimed in any one of claims 1-16 or the optical imaging assembly as claimed in any one of claims 17-22, characterized in that, The distance between the second beam-splitting film and the beam-splitting layer is between 0 and 100 μm.

24. The optical imaging module as claimed in any one of claims 1-16 or the optical imaging assembly as claimed in any one of claims 17-22, characterized in that, The optical imaging assembly further includes a filter element located between the first beam splitter and the second beam splitter for passing light within a predetermined angle range.

25. A floating display device, comprising: One or more optical imaging modules as described in any one of claims 1-16 or one or more optical imaging components as described in any one of claims 17-22; and An image display module configured to emit the image light.

26. The floating display device as described in claim 25, characterized in that, The image display module is a three-dimensional display.

27. A multilayer display device, comprising: The floating display device as described in claim 25 or 26; as well as A transparent display device is disposed downstream of the optical surface of the suspended display device, wherein the display surface of the transparent display device and the suspended image surface are located at different positions.

28. The multilayer display device as claimed in claim 27, characterized in that, The transparent display device includes a transparent display or is implemented by projecting an image onto a transparent / semi-transparent film.

Images