CN116560105A - Optical imaging assembly, optical imaging module and device - Google Patents

Abstract

The invention relates to an optical imaging assembly for floating display, an optical imaging module, a floating display device and a multi-layer display device. The optical imaging assembly includes: a transparent light modulating member having a first surface and a second surface opposite the first surface; a light splitting layer formed in the light modulating member, the light splitting layer having an array of microstructure elements, each microstructure element in the array of microstructure elements having at least two surfaces, the at least two surfaces being mutually perpendicular and having a first light splitting film formed thereon, the array of microstructure elements being for retroreflecting light in at least a first direction so that the light returns in an incident direction; and a second light-splitting film.

Description

Optical imaging assembly, optical imaging module and device

Technical Field

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 floating display device, and a multi-layer display apparatus.

Background

Among the many display technologies, the in-air display technology has received attention from many researchers because of its ability to present images in the air, giving viewers a strong visual impact and also a truly spurious sensory experience.

Conventional hover display techniques include using retroreflective screens, lens groups, or integrated imaging to achieve hover display. However, with the manner of the retroreflective screen or the lens group, the display system is large in volume, and as the suspended image increases, the volume of the display system also needs to increase; for integrated imaging, many microdisplay units are required to project in space to form a floating image, which makes it difficult to achieve high resolution and also makes the screen cost prohibitive.

In addition, the required size of the hover image varies for different scene requirements. In the prior art, although there are various floating display technologies as described above, the size of a floating image displayed by a floating display device is generally limited in the design stage of a manufacturer and cannot be adjusted when in use. As such, when a user desires to present different sizes of floating images according to different application scenes, it is generally necessary to purchase different sizes of floating display devices. For manufacturers of floating display devices, different floating display devices (especially, different optical systems are designed to adapt to different sizes of image display units) need to be designed according to different user requirements, and the floating display devices are adapted one by one, so that great manpower and material resources are consumed.

Thus, there is a need in the art for a new solution for floating displays.

Disclosure of Invention

It is an aim of exemplary embodiments of the present invention to provide an optical imaging assembly that can achieve a floating display with a simple structure.

In particular, exemplary embodiments of the present invention provide an optical imaging assembly comprising: a transparent light modulating member having a first surface and a second surface opposite the first surface; a spectroscopic layer formed within the light modulation member, the spectroscopic layer having an array of microstructure elements, each microstructure element in the array of microstructure elements having at least two surfaces that are perpendicular to each other and on which a first spectroscopic film is formed, the array of microstructure elements for retroreflecting light in at least a first direction so that the light returns in an incident direction; a second light splitting film; wherein image light incident on one of the first surface and the second surface of the light modulation member is light-modulated via the light splitting layer and the second light splitting film to exit from the other of the first surface and the second surface, the light modulation including retroreflection by the microstructure element array, reflection by the second light splitting film, and transmission by the microstructure element array.

In the above optical imaging system, the image light having a large divergence angle is imaged by the imaging element in the first direction at a relatively large aperture angle of the image side and does not generate aberration, and the binocular parallax condition is satisfied, whereby a floating image can be formed in the air while the system is simple in structure and easy to process.

Preferably, each microstructure element is a dihedral element having two adjacent surfaces forming a right angle; or each microstructure element is a corner cube element having three mutually perpendicular adjacent surfaces.

Preferably, one of the first and second light-splitting films is a polarizing light-splitting film, and the other is a light-intensity light-splitting film.

Preferably, the polarizing axis of the polarizing beam-splitting film is disposed at an angle of 45 degrees or 135 degrees to the first direction.

Preferably, the optical imaging assembly further includes a phase retarder disposed between the light modulating member and the second light splitting film. Optionally, the phase retarder is a quarter wave plate.

Preferably, the second light-splitting film is a polarizing light-splitting film, and is disposed outside the first surface of the light-modulating member or between the first surface of the light-modulating member and the light-splitting layer.

Preferably, the first light-splitting film is a polarizing light-splitting film, and the second light-splitting film is disposed outside the second surface of the light-modulating member or between the second surface of the light-modulating member and the light-splitting layer.

Preferably, the optical imaging assembly further comprises a polarizer or a combination of a polarizer and a phase retarder, arranged outside the second surface of the light modulating member. Optionally, the optical imaging assembly further comprises: and the linear polaroid or the circular polaroid is used for reducing the reflection of the polarized light splitting film on the ambient light.

Preferably, the light modulation part is divided into a first medium part and a second medium part by the light splitting layer, and the first medium part and the second medium part have 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, a plurality of mediums exist between the light modulation component and the second light splitting film, and a difference between a refractive index of the plurality of mediums and a refractive index of the first medium part and a refractive index of the second medium part is less than 0.3. Optionally, the first and second media portions are formed of an isotropic material.

Preferably, the microstructure element array is formed along a plane or a curved surface.

Preferably, the object plane and the image plane of the optical imaging assembly are arranged substantially symmetrically with respect to the spectroscopic layer.

Preferably, the light modulation component is configured to perform imaging in the first direction, and the optical imaging assembly further includes an imaging light group configured to perform imaging in a second direction, where the first direction and the second direction are orthogonal to an optical axis of the optical imaging assembly, respectively. Optionally, the microstructure element array is a one-dimensional rectangular grating array, and the light modulation means is integrally formed with a lens for modulating 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 in the second direction. Optionally, the one lens is a fresnel lens, and teeth of the fresnel lens are arranged at equal intervals.

Preferably, the optical imaging assembly may further include a one-dimensional grid transmission array, and the microstructure element array is a one-dimensional rectangular grating array, and the one-dimensional grid transmission array is 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|is less than or equal to 10%.

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

Preferably, the optical imaging system further comprises: and the filter element is positioned between the first light splitting film and the second light splitting film and is used for passing light rays in a preset angle range.

According to another exemplary embodiment of the present invention, there is also provided an optical imaging module for floating display, characterized in that the optical imaging module includes: two optical imaging assemblies as described above, and a first array of microstructure elements in a first optical imaging assembly is disposed substantially orthogonal with respect to a second array of microstructure elements in a second optical imaging assembly, and each of the first microstructure elements and the second microstructure elements is a dihedral angle element.

According to still another exemplary embodiment of the present invention, there is also provided a floating display device including: 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.

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

According to still another exemplary embodiment of the present invention, there is also provided a multi-layered display apparatus including: a floating display device as described above; and a transparent display device disposed optically downstream of the floating display device, wherein a display surface of the transparent display device is located at a different position than the floating image surface.

Preferably, the transparent display means comprises a transparent display or is realized by projecting an image onto a transparent/translucent film.

Other features and aspects will become apparent from the following detailed description, the accompanying drawings, and the claims.

Drawings

The invention may be better understood by describing exemplary embodiments thereof in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a schematic diagram of an optical imaging system 100 for hover display according to some embodiments of the invention;

FIG. 2 shows an example structure of a dihedral angle element array;

FIG. 3 shows a schematic diagram of an optical imaging system 300 according to further embodiments of the invention;

FIG. 4 shows a schematic diagram of an optical imaging assembly 400 according to further embodiments of the invention;

FIG. 5 shows a schematic diagram of an optical imaging assembly 500 according to further embodiments of the invention;

Fig. 6A and 6B show example structures of corner cube element arrays, respectively;

fig. 7 shows a schematic view of a change in polarization state of polarized light irradiated onto a corner cube;

FIG. 8 shows a schematic diagram of an optical imaging assembly 800 according to further embodiments of the invention;

FIG. 9 shows a schematic diagram of an optical imaging assembly 900 according to further embodiments of the invention;

FIG. 10 shows a schematic diagram of an optical imaging assembly 1000 according to further embodiments of the invention;

FIG. 11 shows a schematic diagram of an optical imaging assembly 1100 according to further embodiments of the invention;

fig. 12 shows an example structure of a polarization splitting film;

FIG. 13 shows a schematic diagram of a cholesteric liquid crystal circularly polarizing beamsplitter;

FIG. 14 is a schematic view showing light propagation when the refractive index of the medium on both sides of the spectroscopic layer is different;

FIG. 15 shows possible paths of ghosts;

fig. 16 shows a possible path of ghost image when there is an air layer between the light modulation section 110 and the second light splitting film 120;

fig. 17 shows an example of an ultra fine shutter structure;

FIG. 18 illustrates example locations of optional filter elements in an optical imaging assembly;

fig. 19 shows an example in which the second spectroscopic film 120 is formed integrally with the light modulation member 110;

FIG. 20 shows a schematic diagram for ghost elimination;

FIG. 21 shows a schematic view of an array of microstructure elements in a light modulating component formed along a curved surface;

FIG. 22 shows an example structure of a cylindrical rectangular grating;

FIG. 23 shows a schematic view of the location of an optional polarizer in an optical imaging assembly;

FIG. 24 shows a schematic diagram of an optical imaging assembly 2400 in accordance with an alternative embodiment of the invention;

FIG. 25 shows a schematic diagram of an optical imaging assembly 2500 in accordance with an alternative embodiment of the present invention;

FIG. 26 shows a schematic diagram of an optical imaging system with a light modulating component integrated with a lens;

FIG. 27 shows a schematic diagram of an optical imaging assembly 2700 according to an alternative embodiment of the invention;

FIG. 28 shows a schematic diagram of an optical imaging assembly 2800 in accordance with an alternative embodiment of the invention;

FIG. 29 shows a schematic representation of a one-dimensional grid transmission array propagating light;

fig. 30 shows a schematic diagram of an optical imaging module 3000 according to an exemplary embodiment of the present invention;

fig. 31 shows a schematic block diagram of a hover display device 3100 that may enable hover image stitching according to an embodiment of the invention;

FIG. 32 shows a schematic diagram of a multi-layer display device according to an embodiment of the invention;

FIG. 33 shows a schematic view of a transparent display device implemented by micro-projection;

FIG. 34 shows a schematic diagram of a multi-layer display device implementing naked eye 3D display; and

fig. 35A-35C show illustrative diagrams of display modules employing three-dimensional displays.

Detailed Description

In the following, specific embodiments of the present invention will be described, and it should be noted that in the course of the detailed description of these embodiments, it is not possible in the present specification to describe all features of an actual embodiment in detail for the sake of brevity. It should be appreciated that in the actual implementation of any of the implementations, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that while such a development effort might be complex and lengthy, it would nevertheless be a routine undertaking of design, fabrication, or manufacture for those of ordinary skill having the benefit of this disclosure, and thus should not be construed as having the benefit of this disclosure.

Unless defined otherwise, technical or scientific terms used in the claims and specification should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The terms "first," "second," and the like in the description and in the claims, are not used for any order, quantity, or importance, but are used for distinguishing between different elements. The terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprising" or "comprises", and the like, is intended to mean that elements or items that are immediately preceding the word "comprising" or "comprising", are included in the word "comprising" or "comprising", and equivalents thereof, without excluding other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, nor to direct or indirect connections. The phrase "a is substantially equal to B" is intended to take into account tolerances in the process manufacturing, i.e., the values of a and B may be within ±10% of each other. The phrase "X and Y are substantially orthogonal" is intended to take into account tolerances in the process manufacturing, i.e., the angle between X and Y may be between 80 ° and 100 °.

In this application, all embodiments and preferred embodiments mentioned herein can be combined with each other to form new solutions, unless specifically stated otherwise. In the present application, all technical features mentioned herein as well as preferred features may be combined with each other to form new solutions, if not specifically stated.

In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, which means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

Fig. 1 illustrates a schematic diagram of an optical imaging assembly 100 according to some embodiments of the invention. Referring to fig. 1, an optical imaging assembly 100 according to an embodiment of the present invention may include a transparent light modulating member 110. The light modulation part 110 has a first surface 101 and a second surface 102 opposite to the first surface 101, and may include a spectroscopic layer 111 formed inside thereof. The spectroscopic layer 111 has an array of microstructure elements. Each microstructure element in the microstructure element array may be a dihedral angle element having two adjacent surfaces forming a right angle, and light rays arbitrarily irradiated on the surface of the dihedral angle element, a part of which is reflected at the original angle, as shown in fig. 2. The dihedral corner element has a first spectroscopic film formed on a surface thereof. The array of microstructure elements is used to retroreflect light in a first direction (e.g., the x-direction) to return the light in the incident direction.

The optical imaging assembly 100 also includes a second light splitting film 120. The second light splitting film 120 may be disposed outside the first surface 101 of the light modulating member 110 (as shown in fig. 1). In the optical imaging assembly 100, image light (for example, light emitted from the object surface 10) incident on one of the first surface 101 and the second surface 102 of the light modulation member 110 is light-modulated via the light splitting layer 111 and the second light splitting film 120 to be emitted from the other one of the first surface 101 and the second surface 102. The light modulation may include retroreflection by the light-splitting layer 111 (specifically, the microstructure cell array therein), reflection by the second light-splitting film 120, and transmission by the light-splitting layer 111. As such, the optical imaging assembly 100 may be used to form a suspended real image of an image in the air (e.g., on the image plane 20), or may also be used in a head mounted display device (HMD), such as in place of a concave half mirror in a conventional see-through HMD, because of the special nature of the optical imaging assembly, the use of the assembly does not introduce additional phase differences to the system, while the external view may be seen through, and a larger field angle may be achieved than in existing see-through head mounted display devices.

Fig. 3 shows a schematic diagram of an optical imaging assembly 300 according to further embodiments of the invention. In the optical imaging assembly 300, the first light splitting film on the microstructure elements may be a light intensity splitting film (e.g., 70% reflective 30% transmissive splitting film) and the second light splitting film 120 may be a linear polarization splitting film (e.g., transmitting p-polarized light and reflecting s-polarized light) with the polarization axis of the linear polarization splitting film at 45 degrees or 135 degrees to the microstructure element array (x-direction or y-direction). Referring to fig. 3, the image light (divergent light) emitted from the o-point on the object plane may be linearly polarized light having a polarization direction in the xy plane at an angle of 45 degrees to the x-axis, incident on the spectroscopic layer 111 from the second surface 102 of the light modulation section 110, a part of the light retroreflected via the spectroscopic layer 111 (specifically, the microstructure unit array therein) without participating in the final imaging (this part of the retroreflected light is not shown), the image light transmitted through the spectroscopic layer 111 is reflected by the second spectroscopic film 120 (for transmitting p-polarized light and reflecting s-polarized light), and the polarization transmission axis of the second spectroscopic film is in the xy plane at an angle of-45 degrees to the x-axis, and the polarization reflection axis (absorption axis) of the second spectroscopic film is at an angle of 45 degrees to the x-axis. Polarized light reflected by the second light splitting film becomes-45 ° in polarization direction from the x-axis, is incident on the light splitting layer 111 from the first surface 101, a part of the light is transmitted through the light splitting layer 111 (specifically, the microstructure unit array therein) without participating in final imaging (this part of the transmitted light is not shown), another part of the light is reflected by the light splitting layer 111 twice, the angle between the polarization direction of the first reflected light and the x-axis becomes-45 °, and the polarization direction of the second reflected light becomes-45 ° from the x-axis. The polarization direction of the imaging light retroreflected from the spectroscopic layer 111 is the same as the polarization transmission axis direction of the second spectroscopic film 120, and thus is transmitted by the second spectroscopic film 120 to be converged at o' on the image plane 20.

Fig. 4 shows a schematic diagram of an optical imaging assembly 400 according to further embodiments of the invention. In the optical imaging assembly 400, the second light splitting film 120 may also be a circularly polarized light splitting film having circular polarization dichroism, and the material selectively transmits or reflects one of two circularly polarized light components of the light beam having opposite rotation directions. For example, the circularly polarizing beam splitter film may be a cholesteric liquid crystal film, in which almost all circularly polarized light having the same rotation direction as the liquid crystal is reflected, and almost all circularly polarized light having the opposite rotation direction is transmitted. As shown in fig. 4, the image light (divergent light) emitted from the o-point on the object plane is right-handed polarized light, which is incident on the spectroscopic layer 111 from the second surface 102 of the light modulation section 110, and a part of the light is retroreflected via the spectroscopic layer 111 (specifically, the microstructure unit array therein) without participating in the final imaging, and the imaging light transmitted through the spectroscopic layer 111 is reflected by the second spectroscopic film 120 (for transmitting left-handed circularly polarized light and reflecting right-handed circularly polarized light). The right circularly polarized light reflected by the second light splitting film changes its polarization direction into left circularly polarized light, and is incident on the light splitting layer 111 from the first surface 101, a part of the light is transmitted through the light splitting layer 111 (specifically, the microstructure unit array therein) without participating in final imaging, another part of the light is reflected twice by the light splitting layer 111, the polarization direction of the first reflected light is right circularly polarized light, and the polarization direction of the second reflected light is left circularly polarized light. The imaging light retroreflected from the spectroscopic layer 111 exits through the second spectroscopic film 120 to be converged at o' on the image plane 20.

Fig. 5 shows a schematic diagram of an optical imaging assembly 500 according to further embodiments of the invention. An optical imaging assembly 500 according to an embodiment of the invention may include a transparent light modulating component 110. The light modulation part 110 has a first surface 101 and a second surface 102 opposite to the first surface 101, and may include a spectroscopic layer 111 formed inside thereof. The spectroscopic layer 111 has an array of microstructure elements. Each microstructure element in the microstructure element array may be a corner cube element having three mutually perpendicular adjacent surfaces, as shown in fig. 6A or 6B. The spectroscopic layer 111 has a first spectroscopic film formed thereon. The microstructure element array is used for retroreflecting light so that the light returns in the incident direction.

In the optical imaging assembly 500, the first light splitting film on the microstructure elements may be a light intensity splitting film (e.g., a 50% reflective 50% transmissive splitting film) and the second light splitting film 120 may be a linear polarization splitting film (e.g., transmitting p-polarized light and reflecting s-polarized light). The second light splitting film 120 may be disposed outside the first surface 101 of the light modulating member 110. The optical imaging assembly 500 further includes a quarter wave plate 130, the quarter wave plate 130 being disposed between the light modulating component 110 and the second light splitting film 120, the axial angle of the quarter wave plate 130 and the linear polarization light splitting film being 45 degrees or 135 degrees. It is contemplated that quarter wave plate 130 may also be a combination of 1/4 wave plate +1/2 wave plate. As shown in fig. 5, the image light (divergent light) emitted from the o-point on the object plane 10 is left circularly polarized light, is incident on the spectroscopic layer 111 from the second surface 102 of the light modulation section 110, and a part of the light is retroreflected via the spectroscopic layer 111 (specifically, the microstructure unit array therein) without participating in the final imaging, and the imaging light transmitted through the spectroscopic layer 111 is converted into s-polarized light by the 1/4 wave plate, reflected by the second spectroscopic film 120 (for transmitting p-polarized light and reflecting s-polarized light), is converted into left circularly polarized light again by the 1/4 wave plate, and is irradiated onto the corner cube. As shown in fig. 7, each time the circularly polarized light is reflected once, the direction of rotation of the circularly polarized light is changed once to be emitted as right-handed polarized light after being reflected once on each of the 3 surfaces of the corner cube, the right-handed circularly polarized light is converted again to p-polarized light through the 1/4 wave plate, and the p-polarized light is emitted through the second light splitting film to form a floating real image of an image in the air (for example, on the image plane 20).

Fig. 8 shows a schematic diagram of an optical imaging assembly 800 according to further embodiments of the invention. In the optical imaging assembly 800, the second light splitting film 120 may also be a circularly polarized light splitting film. The second light splitting film 120 may be disposed outside the first surface 101 of the light modulating member 110. The quarter wave plate 130 has an axial direction of 0 degrees and is disposed between the light modulation section 110 and the second light splitting film 120. As shown in fig. 8, the image light (divergent light) emitted from the o-point on the object plane 10 is 45-degree linearly polarized light, is incident on the spectroscopic layer 111 from the second surface 102 of the light modulation member 110, and a part of the light is retroreflected via the spectroscopic layer 111 (specifically, the microstructure unit array therein) without participating in the final imaging, the imaging light transmitted through the spectroscopic layer 111 is converted into right-handed circularly polarized light through the 1/4 wave plate, reflected by the second spectroscopic film 120 (for transmitting left-handed circularly polarized light and reflecting right-handed circularly polarized light), becomes left-handed circularly polarized light after reflection, is converted into 45-degree polarized light again through the 1/4 wave plate, irradiates onto the corner prism, becomes-45-degree polarized light after each reflection once in the polarization direction of the linearly polarized light, is converted into left-handed circularly polarized light again through the 1/4 wave plate, and exits through the second spectroscopic film 120 to form a suspended real image of the image in the air (for example, on the image plane 20).

Fig. 9 shows a schematic diagram of an optical imaging assembly 900 for use in hover display according to further embodiments of the invention. The optical imaging assembly 900 may include a transparent light modulating component 110. The light modulation part 110 has a first surface 101 and a second surface 102 opposite to the first surface 101, and may include a spectroscopic layer 111 formed inside thereof. The spectroscopic layer 111 has an array of microstructure elements. Each microstructure element in the microstructure element array may have at least two surfaces that are perpendicular to each other (the microstructure may be a dihedral angle structure or a corner cube structure), and a first light-splitting film may be formed thereon (for example, a polarizing light-splitting film that transmits p-polarized light and reflects s-polarized light). The array of microstructure elements is used to retroreflect light in at least a first direction (e.g., the x-direction) to return the light in the direction of incidence.

The optical imaging assembly 900 also includes a second light splitting film 120 and a quarter wave plate 130. The second light splitting film 120 may be a light intensity splitting film (e.g., a 50% reflective 50% transmissive splitting film) and may be disposed outside the second surface 102 of the light modulating member 110. The quarter wave plate 130 is disposed between the light modulation part 110 and the second light splitting film 120. It is contemplated that quarter wave plate 130 may also be a combination of 1/4 wave plate +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 part of the light is reflected by the second light splitting film 120 without participating in final imaging, the imaging light transmitted through the second light splitting film 120 is modulated into s-polarized image light by the quarter wave plate 130, is incident on the light splitting layer 111 from the second surface 102 of the light modulating member 110, the s-polarized image light is retroreflected by the light splitting layer 111 (specifically, the microstructure cell array therein), the retroreflected s-polarized image light is split again by the second light splitting film 120 through the quarter wave plate 130, a part of the retroreflected light is transmitted by the second light splitting film 120 without participating in final imaging, and another part of the imaging light reflected from the second light splitting film 120 is modulated again by the quarter wave plate 130 into p-polarized light, and is transmitted by the light splitting layer 111, thereby converging at the o' on the image plane 20.

Fig. 10 shows a schematic diagram of an optical imaging assembly 1000 for use in hover display according to further embodiments of the invention. The optical imaging assembly 1000 may include a transparent light modulating component 110. The light modulation part 110 has a first surface 101 and a second surface 102 opposite to the first surface 101, and may include a spectroscopic layer 111 formed inside thereof. The spectroscopic layer 111 has an array of microstructure elements. Each microstructure element in the microstructure element array may be a dihedral angle element having two adjacent surfaces forming a right angle, light rays arbitrarily irradiated on the surface of the dihedral angle element, a portion of the light rays being reflected at the original angle, and a first light-splitting film formed thereon. The optical imaging assembly 1000 also includes a second light splitting film 120 and a quarter wave plate 130. The first spectroscopic layer 111 may be plated with a light intensity spectroscopic film (e.g., a 50% reflective 50% transmissive spectroscopic film), and the second spectroscopic film 120 may be a circularly polarized spectroscopic film and disposed outside the second surface 102 of the light modulating member 110. The quarter wave plate 130 is disposed between the light modulation section 110 and the second light splitting film 120, and an angle between an axial direction of the quarter wave plate and a horizontal direction is 45 °. As shown in fig. 10, the image light (divergent light) emitted from the o-point on the object surface 10 is linearly polarized light whose polarization axis is horizontal, and is incident on the spectroscopic layer 111 from the second surface 102 of the light modulation section 110, and a part of the light is retroreflected via the spectroscopic layer 111 (specifically, the microstructure unit array therein) without participating in the final imaging, and the imaging light transmitted through the spectroscopic layer 111 is converted into left-circularly polarized light via the quarter wave plate and reflected by the second spectroscopic film 120 (for reflecting the left-circularly polarized light and transmitting the right-circularly polarized light). The left circularly polarized light reflected by the second light splitting film 120 changes its polarization direction into right circularly polarized light, and after passing through the quarter wave plate 130, the light is converted into linearly polarized light with a horizontal polarization direction, and is incident on the light splitting layer 111 from the first surface 101, and a part of the light is transmitted through the light splitting layer 111 (specifically, the microstructure unit array therein) without participating in final imaging, and another part of the light is reflected twice by the light splitting layer 111, and the polarization direction of the light reflected each time is horizontally linearly polarized light. The image light retroreflected from the spectroscopic layer 111 is converted into right-circularly polarized light again through the quarter wave plate 130, and exits through the second spectroscopic film 120 to be converged at o' on the image plane 20.

Fig. 11 shows a schematic diagram of an optical imaging assembly 1100 for floating display according to further embodiments of the invention. The optical imaging assembly 1100 may include a transparent light modulating component 110. The light modulation part 110 has a first surface 101 and a second surface 102 opposite to the first surface 101, and may include a spectroscopic layer 111 formed inside thereof. The spectroscopic layer 111 has an array of microstructure elements. Each microstructure element in the microstructure element array may be a dihedral angle element having two adjacent surfaces forming a right angle, light rays arbitrarily irradiated on the surface of the dihedral angle element, a portion of the light rays being reflected at the original angle, and a first light-splitting film formed thereon. The optical imaging assembly 1100 also includes a second light splitting film 120 and a half wave plate 130. The first spectroscopic layer 111 is coated with a light intensity spectroscopic film (e.g., 50% reflection 50% transmission spectroscopic film), and the second spectroscopic film 120 is a linear polarization spectroscopic film (transmission p-light, reflection s-light) and may be disposed outside the second surface 102 of the light modulation member 110. The half wave plate 130 is disposed between the light modulation part 110 and the second light splitting film 120, and an axial direction of the half wave plate forms an angle of 22.5 ° or 67.5 ° with the horizontal direction. As shown in fig. 11, the image light (divergent light) emitted from the o-point on the object surface 10 is linearly polarized light of 45 °, is incident on the spectroscopic layer 111 from the second surface 102 of the light modulation section 110, and a part of the light is retroreflected via the spectroscopic layer 111 (specifically, the microstructure cell array therein) without participating in the final imaging, and the imaging light transmitted through the spectroscopic layer 111 is converted into s-polarized light via the half-wave plate and reflected by the second spectroscopic film 120. After passing through the half wave plate 130, the light reflected by the second light splitting film is converted into linearly polarized light with a polarization direction of-45 °, and is incident on the light splitting layer 111 from the first surface 101, a part of the light is transmitted through the light splitting layer 111 (specifically, the microstructure unit array therein) without participating in final imaging, and the other part of the light is reflected twice by the rectangular grating of the light splitting layer 111, the first reflected light is linearly polarized light with a polarization direction of-45 °, and the second reflected light is converted into linearly polarized light with a polarization direction of-45 °. The image light retroreflected from the spectroscopic layer 111 is converted into p-polarized light again through the half wave plate 130, and exits through the second spectroscopic film 120, thereby converging at o' on the image plane 20.

It will be appreciated that since the microstructure element array of the spectroscopic layer 111 is a conjugate imaging element, the object plane 10 and the image plane 20 of the above various optical imaging assemblies may be arranged substantially symmetrically with respect to the spectroscopic layer 111. The use of a conjugated imaging element has the advantage that the positional relationship (object to image) is conjugated, the image is not magnified, and no aberration occurs. In addition, since the optical paths are 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 assemblies 100, 300, 400, 500, 800, 900, 1000, or 1100 of the present application may be used for suspended imaging when the first surface 101 is in light and the second surface 102 is out of light, and the second surface 102 is in light, respectively, when the first surface 102 is in light and the second surface 101 is out of light.

In some embodiments of the present invention, the polarization beam splitting film may be a DBEF structure, as shown in fig. 12; alternatively, the polarizing beam splitting film may be a metal wire grid; alternatively, the polarization beam splitter film may be formed by a multilayer dielectric coating film. Alternatively, the polarizing beam-splitting film may be a cholesteric liquid crystal circular polarizing beam-splitting film, as shown in fig. 13, and the film layers may be in a flat plate structure or may be made on a microstructure.

As shown in fig. 14, the spectroscopic layer 111 divides the light modulation section 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 light rays with different angles are not refracted when passing through the microstructure, and a single suspended image with better quality can be formed. If the refractive indices are not the same (e.g., n1> n2, as shown in FIG. 4), the imaging light rays may diverge or converge after passing through the right angle microstructure array, resulting in multiple images (at least 2) being formed, affecting imaging quality.

In a preferred embodiment of the invention, the refractive index of the first medium part and the second medium part may be between 1.3 and 1.8, i.e. 1.3.ltoreq.n1=n2.ltoreq.1.8.

In a preferred embodiment of the present invention, the first medium part and the second medium part of the light modulation member 110 may be formed of isotropic materials so as to avoid birefringence.

In a preferred embodiment of the present invention, the optical imaging assembly 100 may include a transparent light modulating member 110. The light modulation part 110 has a first surface 101 and a second surface 102 opposite to the first surface 101, and may include a spectroscopic layer 111 formed inside thereof. The spectroscopic layer 111 has an array of microstructure elements. Each microstructure element in the microstructure element array may be a dihedral angle element having two adjacent surfaces forming a right angle, light rays arbitrarily irradiated on the surface of the dihedral angle element, a portion of the light rays being reflected at the original angle, and a first light-splitting film formed thereon. The array of microstructure elements is used to retroreflect light in a first direction (e.g., the x-direction) to return the light in the incident direction.

Preferably, the first light-splitting film may be a depolarized light-intensity light-splitting film, and the p-light and the s-light have substantially the same reflectivity. Preferably, |Rs-Rp| <10%. This ensures that the polarization state of the light is not changed as much as possible when it is transmitted inside the light modulating means, for example, left-circularly polarized light is transmitted or left-circularly polarized light is transmitted instead of becoming elliptically polarized light. With this structure, there are mainly two paths of ghost images, as shown in fig. 15. One is that the incident light is reflected by the polarization beam splitting film and irradiates onto the light splitting layer of the right angle grating microstructure, the light reflected by the primary mirror surface of the right angle grating irradiates onto the polarization beam splitting film and is reflected (the normal imaging light path is reflected by the right angle grating for the second time, the light is retroreflected according to the original path), and the reflected light is reflected once or more times again on the right angle microstructure and then is emitted to form ghost images/stray light. Another type of ghost path is that light emitted from an object point is incident on the rectangular grating microstructure, the light is not directly transmitted but is specularly reflected by one surface of the rectangular grating (because the first light-splitting film is partially transmitted light and partially reflected), the light reflected by the rectangular grating irradiates the polarizing light-splitting film and is reflected, and the reflected light is reflected on the rectangular microstructure again after one or more reflections to form ghost/flare.

When there is an air layer between the light modulation component 110 and the second light splitting film 120, the incident light is reflected by the polarizing light splitting film and then irradiates onto the micro-structure light splitting layer of the rectangular grating, and the light once reflected by the rectangular grating is irradiated onto the first surface 101 of the light modulation component 110 and is totally reflected (because the angle of the once reflected light is >45 °), as shown in fig. 16. Another ghost path, i.e. light from the object point is incident on the quarter-grating microstructure, which is not directly transmitted but specularly reflected by one of the facets of the quarter-grating, which reflected light impinges on the first surface of the light modulating means, which is also totally reflected (because the angle of the light reflected by the quarter-grating is >45 °). The light totally reflected by the first surface on the light modulation component in the two paths irradiates on the right-angle microstructure again, and is reflected once or multiple times to be emitted to form ghost images/parasitic light. Therefore, in the preferred embodiment of the present invention, there is substantially no gap (air layer) between the light modulation member 110 and the second light splitting film 120, and for example, it may be glued as a whole.

Further, the light modulation section 110 and the second light splitting film 120 allow a plurality of mediums (e.g., lenses, adhesives, etc.) to exist therebetween, and the refractive indexes of these mediums may be substantially equal and the difference between the refractive indexes of the first medium portion and the second medium portion is less than 0.3, which contributes to reduction of parasitic light and ghost images.

Optionally, the optical imaging assembly according to an embodiment of the present invention may further comprise a filter element for passing light rays of a predetermined angular range. The filter element may be an ultra-fine shutter (microlouver) structure, or may be implemented by using a coating film. An example of an ultra-fine louver structure is shown in fig. 17, which can be used to absorb light at a large angle by passing light at an angle, preferably within a range of + -45 degrees, so that normal display light can pass therethrough, while for the two stray light/ghost light paths described previously, the effect of eliminating ghost images is achieved because the angle is large to be absorbed. In addition, the light transmission range is set within a range of + -45 DEG, the observable angle range with >90 DEG is ensured, and the optical system has higher optical efficiency.

Preferably, a filter element (e.g., a light control film) is placed between the second light splitting film (e.g., a polarizing light splitting film) and the first light splitting film (e.g., an energy splitting film), as shown in fig. 18.

In some embodiments of the present invention, the second light splitting film 120 is disposed on the surface 101 of the light modulating member 110, and the second light splitting film 120 is in close contact with the first surface 101 without an air space. Alternatively, the second light splitting film 120 may be formed integrally with the light modulating member 110 as a single member. As shown in fig. 19, the second spectroscopic film 120 may be arranged between the first surface 101 of the light modulation member 110 and the spectroscopic layer 111. Those skilled in the art will appreciate that in some embodiments, the second light splitting film 120 may also be disposed between the second surface 102 of the light modulating member 110 and the light splitting layer 111.

Whether or not the second light-splitting film 120 is integrally formed with the light modulation member 110, the distance d between the second light-splitting film 120 and the light-splitting layer 111 (for example, the tooth peak of the microstructure unit) is preferably between 0 and 100 μm. The ghost image light reflected once by the right angle grating irradiates on the right angle structure again after being reflected by the first surface 101, and then is reflected for multiple times, and the ghost image light can be controlled in the Pitch range of 1-2 right angle structures in the horizontal direction by reducing the distance d. Thus, even if the ghost rays are emitted, the ghost rays are overlapped with normal imaging as shown in fig. 20, thereby achieving the purpose of eliminating the ghost.

In some embodiments of the present invention, the microstructure element array in the light modulation part 110 may be formed along a plane or may be formed along a curved surface as shown in fig. 21. For example, in the case where the microstructure elements are dihedral elements, the microstructure element array may be formed as a cylindrical rectangular grating, which is curved in the y-direction and a one-dimensional rectangular grating structure in the x-direction, as shown in fig. 22.

Optionally, in some embodiments, the optical imaging assembly 100, 300, 400, 500, 800, 900, 1000, or 1100 may further include a polarizer, or may include a combination of a polarizer and a phase retarder for eliminating light reflected back from the light splitting film. As shown in fig. 23, in the optical imaging assembly 100, a polarizer may be disposed outside the second surface of the light modulation member.

Fig. 24 and 25 show schematic diagrams of optical imaging assemblies 2400 and 2500 for floating display according to alternative embodiments of the present invention. Several details of the optical imaging assemblies 2400 and 2500 are the same as the optical imaging assemblies 100, 300, 400, 500, 800, 900, 1000, or 1100, respectively, described above with respect to fig. 1, and are not repeated here. The optical imaging assembly 2400 may include a polarizer 140. The polarizer 140 may be disposed outside the second surface 102 of the light modulation member 110, the light splitting layer 111 in the optical imaging assembly 2400 may have a dihedral angle micro prism array structure, and the first light splitting film 110 may be a light intensity splitting film. The optical imaging assembly 2500 may include a polarizer 140 and a second quarter wave plate 150. The polarizer 140 may be disposed outside the second surface 102 of the light modulation part 110, and the second quarter wave plate 150 may be disposed between the light modulation part 110 and the polarizer 140. The light splitting layer 111 in the optical imaging assembly 2500 is a corner cube array structure, and the first light splitting film 110 is a polarizing light splitting film.

In the optical imaging assembly 2400, the incident light is changed to 45 degrees with respect to the x-axis after passing through the polarizer 140, and is incident on the spectroscopic layer 111 from the second surface 102 of the light modulation member 110, the imaging light transmitted through the spectroscopic layer 111 is reflected by the second spectroscopic film 120 (for transmitting p-polarized light and reflecting s-polarized light), the polarization transmission axis of the second spectroscopic film is in the xy plane at an angle of-45 degrees with respect to the x-axis, and the polarization reflection axis (absorption axis) of the second spectroscopic film is 45 degrees with respect to the x-axis. Polarized light reflected by the second light splitting film, the polarized direction and the x-axis included angle become-45 degrees, and the polarized light is incident on the light splitting layer 111 from the first surface 101, and 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 that the purpose of eliminating stray light is achieved. The other part of the light is reflected twice by the light-splitting layer 111, the angle between the polarization direction of the first reflected light and the x-axis becomes 45 °, and the angle between the polarization direction of the second reflected light and the x-axis becomes-45 °. The polarization direction of the imaging light retroreflected from the spectroscopic layer 111 is the same as the polarization transmission axis direction of the second spectroscopic film 120, and thus is transmitted by the second spectroscopic film 120 to be converged at o' on the image plane 20.

In the optical imaging assembly 2500, the incident light is changed into p polarized light after passing through the polarizer 140, changed into circular polarized light through the second quarter wave plate 150, split by the light intensity splitting film 120, and part of the light is changed into s polarized light through the first quarter wave plate 130, reflected by the polarization splitting layer 111, and then retroreflected by the microstructure array, and the light returns according to the original path, meanwhile, as the light passes through the first quarter wave plate 130 twice, the light is converted into p polarized light, and is emitted through the polarization splitting film 111, so that the light emitted by the object point o is converged at the other side of the system, and the image point o' is formed. In particular, the light returned by the light intensity splitting film passes through the second quarter wave plate 150 again, and the light is converted into s-polarized light, which is absorbed by the polarizer 140, thereby achieving the purpose of eliminating stray light.

Optionally, in some embodiments, the optical imaging assembly 2400 or 2500 may further include an additional polarizer for absorbing non-imaging light transmitted from the polarizing beam-splitting film and reducing reflection of ambient light (non-imaging light) by the polarizing beam-splitting film. For example, taking the optical imaging assembly 2400 as an example, the additional polarizer 160 may be disposed outside the second light splitting film 120.

Optionally, in some embodiments, the light modulating component 110 may be configured to image only in a first direction (e.g., to concentrate light emanating from the object point o at o 'in the x-direction), then the optical imaging assembly 100, 300, 400, 500, 800, 900, 1000, 1100, 2400, or 2500 may further comprise an imaging light set configured to image in a second direction (e.g., to concentrate light emanating from the 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, respectively. For example, the imaging light group may include one or more lenses and an aperture stop. In particular, the image-side aperture angle of the imaging optics in the first direction is preferably larger than the image-side aperture angle of the optics in the second direction.

Alternatively, in some embodiments, the light modulating component 110 in the optical imaging assembly 100, 300, 400, 500, 800, 900, 1000, 1100, 2400, or 2500 may be formed as a single component with the additional lens 210, i.e., a "lens & grading" structure, such as by injection molding the microstructured light splitting layer and lens integrally, or may be glued with the additional lens 210 to form an integral structure, as shown in fig. 26. The lens 210 may be used to modulate the imaging light in a second direction to aid in imaging or to optimize imaging quality. The second direction may be substantially orthogonal to the first direction.

Fig. 27 shows a schematic diagram of an optical imaging assembly 2700 according to an alternative embodiment of the invention. The optical imaging assembly 2700 may include any of the optical imaging assemblies described above (fig. 27 illustrates the optical imaging assembly 100 of fig. 1), and the example optical imaging assembly 2700 may further include a first lens 2710, a second lens 2720, a third lens 2730, and a fourth lens 2740. A first polarizer (not shown) may be disposed outside the second surface 102 of the light modulation part 110. In this example, the light modulating component 110 in the optical imaging assembly 100 may be used to modulate imaging light in the x-direction for imaging, while the first, second, and third lenses, fourth, may be used to modulate imaging light in the y-direction, where the first lens 2710 is an aperture stop of the optical system in the y-direction. Alternatively, the first lens 2710 may be a fresnel lens with equal spacing between fresnel lens teeth to facilitate seamless stitching (as described below). As described above, imaging of a floating image can be achieved using only the light modulation section 110, but the floating image moves in the y direction with the movement of the observation position, so that the combination of the first lens 2710, the second lens 2720, the third lens 2730, and the fourth lens 2740 can be used to adjust the y direction, solve the problem of positioning the floating image in the y direction in space, and thus can achieve a larger angle of view in the horizontal direction. The optical imaging assembly 2700 may further include a second polarizer disposed between the polarizing beamsplitter (e.g., the second beamsplitter 120, not shown in fig. 27) and the image plane for reducing reflection of the external light (non-imaging light) by the polarizing beamsplitter. As such, image light on object plane 10 may form a floating image on image plane 20 via example optical imaging assembly 2700.

Optionally, in some embodiments, the optical imaging assembly 100, 300, 400, 500, 800, 900, 1000, 1100, 2400, 2500, 2600, and 2700 may further comprise a one-dimensional grid array plate for imaging in the second direction. Fig. 28 shows a schematic diagram of an optical imaging assembly 2800 in accordance with an alternative embodiment of the invention. The optical imaging assembly 2800 may include any of the optical imaging assemblies described above (e.g., may include a polarizer 140, a light modulating member 110, a second light splitting film 120, and a second polarizer 160)). The microstructure cell array in the light modulation section 110 in the optical imaging assembly 2800 is a dihedral angle element array in the x direction, that is, a structure in which the x direction is a one-dimensional rectangular grating array. The optical imaging assembly 2800 may also include a flat plate with a one-dimensional grid transmission array 310 in the y-direction. The one-dimensional grid transmission array structure can be formed by laminating a plurality of parallel glass plates, wherein the lamination surface is plated with a metal reflecting film. As shown in fig. 29, the object point o is optically conjugate with the image point o', the object plane and the image plane of the structure are equal in size, and no aberration occurs. In the prior art, solutions have been proposed for forming a suspended image using two mutually orthogonal one-dimensional grid transmission arrays. The configuration employing the example optical imaging assembly 2800 has the advantage of low cost and low ghosting compared to the prior art.

There is also provided, in accordance with an exemplary embodiment of the present invention, an optical imaging module for use in hover display. Fig. 30 shows a schematic diagram of an optical imaging module 3000 according to an exemplary embodiment of the present invention. The optical imaging module 3000 includes two optical imaging assemblies described above, one of which may include, for example, the polarizer 140, the light modulating member 110, and the second light splitting film 120, and an additional polarizer 160, and the other of which may include, for example, the polarizer 140', the light modulating member 110', and the second light splitting film 120'. The first array of microstructure elements in the light modulating component 110 of the first optical imaging assembly is arranged substantially orthogonally with respect to the second array of microstructure elements in the light modulating component 110' of the second optical imaging assembly, and each of the first microstructure elements and the second microstructure elements is a dihedral angle element, i.e. a one-dimensional rectangular grating array. The first optical imaging assembly may be used to modulate imaging light at object point o in a first direction (e.g., x-direction), while the second optical imaging assembly may be used to modulate imaging light at object point o in a second direction (e.g., y-direction), ultimately converging in the air to form a suspended image point o'. There is also provided, in accordance with still further embodiments of the present invention, a floating display device comprising 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 an object plane of the optical imaging assembly and/or the optical imaging module by means of direct display or indirect projection, and the image light then forms a floating image in the air through the optical system. If a large-sized floating display is to be realized, a larger optical element needs to be processed, which leads to a rapid increase in processing cost and a decrease in accuracy of the optical element. The present invention thus allows for providing a variable size floating display device comprising one or more image display units and one or more optical imaging assemblies and/or optical imaging modules forming a plurality of floating images in space, the plurality of floating images being stitched into a complete floating image. According to the technical scheme, the suspended image seamless splicing is realized, and meanwhile, the manufacturing cost is low, so that the suspended display device is more compact.

Fig. 31 shows a schematic block diagram of a hover display device 3100 that may enable hover image stitching according to an embodiment of the invention. Referring to fig. 31, a floating display device 3100 according to an embodiment of the present invention may include a display module 3110 and a plurality of optical imaging modules 3120 _1～n . Optical imaging module 3120 _i May be constituted by the optical imaging assembly described above, or may be the optical imaging module 3000. The display module 3110 may be configured to emit display light that constitutes a target image. Multiple optical imaging modules 3120 _1～n May be configured to receive display light emitted from the display module 3110 to form a floating image in the air. Each optical imaging module 3120 _i Defining an object plane 10 and an image plane 20. The display module 3110 (in particular 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 3110 can pass through the plurality of optical imaging modules 3120 _1～n Is focused on the image plane 20.

In an embodiment of the present invention, the display module 3110 may be formed by splicing a plurality of display units or be a single display device, and the single display device may be a single complete display area or have a plurality of independent display areas, so that the display module 3110 may include a plurality of display portions arranged along the y direction. Each display may be configured to display a respective portion of the target image. Target image displayed on the display module 3110 and a plurality of optical imaging modules 3120 _1～n The floating image presented at the floating image plane (i.e., image plane 20) may be in an inverted imaging relationship in the y-direction.

According to another exemplary embodiment of the present invention, there is also provided a multi-layered display apparatus.

Fig. 32 shows a schematic diagram of a multi-layer display device 3200 according to an embodiment of the invention.

The multi-layer display apparatus 3200 may include the floating display device 3100 and the transparent display device 200 described previously. The transparent display device 200 may be disposed on the light-emitting 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 surface 20 of the floating display device 3100, specifically between the floating image surface 20 and the floating display device 3100. The transparent display part 200 may have a high transmittance such as a transparent OLED/LED/LCD display or film (slide show). The transparent display device 200 may also be obtained from a micro-projected image by providing a transparent film (film haze less than < 5%) in front of the floating display device 3100, as shown in fig. 33. Alternatively, the transparent film may be angularly selective to light, diffuse for high angle light (projection images), and directly transmit for low angle light (hover images).

The multi-layered display device 3200 according to the exemplary embodiment of the present invention is described above. The multi-layered display apparatus 3200 has a display surface 1 and a display surface 2, the floating display device 3100 may form a floating image at the display surface 1 (image surface 20), and the transparent display device 200 may display different information at the display surface 2. In this way, the secondary information can be displayed on the display surface 2, and the important information is presented at the display surface 1, so that the efficiency and experience of people for acquiring the information are improved. Alternatively, images with the same size may be displayed on the display surface 1 and the display surface 2, and the difference in shade and color between the distance between the object and the viewer may be utilized to further overlap the front and rear object images together, so that the viewer may generate a stereoscopic impression, and thus naked eye 3D display may be implemented, as shown in fig. 34.

Alternatively, the display module 3110 may be an naked eye three-dimensional display, which may be a multi-view autostereoscopic display or a light field display. As shown in fig. 35A, a typical naked-eye three-dimensional display is composed of a flat panel display and a micro-optical unit, which may be a microlens or a slit grating. The flat panel display generates parallax images, which are respectively sent to the left eye and the right eye of an observer after passing through the micro-optical unit, and a stereoscopic impression is generated by utilizing the binocular parallax effect of human eyes. As shown in fig. 35B, the point a1 on the display module 3110 enters the right eye, the point a2 enters the left eye, and the point seen by the human eye due to the binocular parallax principle is the point a, which is in front of the screen. The point b1 on the display screen enters the right eye, the point b2 enters the left eye, and the point seen by the human eye due to the binocular parallax principle is the point b, which is at the rear of the screen. The left and right eyes commonly see the c point on the screen, and thus the position of the c point is perceived on the screen. Thus, the 3D image presented by the conventional naked eye three-dimensional display is a 3D image with the screen as a depth center and within a certain depth range from front to back. Because human eyes focus on a physical screen of the three-dimensional display during watching, three-dimensional images floating in space cannot be perceived, and experience is affected.

The display module 3110 in the present invention can use a multi-viewpoint/light field display, which can well solve the problem, the screen surface of the multi-viewpoint/light field display is projected into the space through the optical imaging module 3120 in the present invention to form a floating image surface, and by displaying parallax images on the multi-viewpoint/light field display, a 3D image with the floating image surface as the depth center and within a certain range can be formed in the space. As shown in fig. 35C, on the floating image plane, the point a is on the front depth plane, the point b is on the rear depth plane, and the point C is on the floating image plane of the display device, so that the formed 3D image is completely floating in the air, and better 3D effect experience is achieved.

The optical imaging assembly, the optical imaging module, the floating display device, and the multi-layer display apparatus according to the exemplary embodiments of the present invention are described above in detail. The invention has the advantages that: 1) The optical imaging assembly/module has simple structure, is easy to process, and can effectively reduce the cost; 2) The system can be an aberration-free system, optical aberration is not required to be corrected, and the angle of view is large; 3) Various sizes of display modules (or a specific number of display units) and a specific number of optical imaging components/modules can be adopted according to the requirements to realize suspension display of different sizes, namely, the display is used after assembly, which is particularly beneficial to realizing large-size suspension display; 4) The optical imaging assembly/module is designed at one time, and the same optical imaging module with corresponding quantity is used for seamless splicing of the floating images according to the required floating image size, so that different optical imaging assemblies/modules are not required to be designed for different floating image sizes; 5) The ghost image is less. The optical imaging component/module is adopted to realize light field reconstruction of image light in the air, and is a light field three-dimensional display technology. The aperture angle of the image space, which is imaged by the optical imaging component/module along the x direction, is relatively large, and the binocular parallax condition is satisfied, so that floating display of the image can be realized.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with one another. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the various embodiments of the invention without departing from the scope thereof. While the dimensions and types of materials described herein are intended to define the parameters of the various embodiments of the invention, the various embodiments are not meant to be limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reading the above description. The scope of the various embodiments of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims (30)

1. An optical imaging assembly, the optical imaging assembly comprising:

a transparent light modulating member having a first surface and a second surface opposite the first surface;

a spectroscopic layer formed within the light modulation member, the spectroscopic layer having an array of microstructure elements, each microstructure element in the array of microstructure elements having at least two surfaces that are perpendicular to each other and on which a first spectroscopic film is formed, the array of microstructure elements for retroreflecting light in at least a first direction so that the light returns in an incident direction; and

A second light splitting film;

wherein image light incident on one of the first surface and the second surface of the light modulation member is light-modulated via the light splitting layer and the second light splitting film to exit from the other of the first surface and the second surface, the light modulation including retroreflection by the microstructure element array, reflection by the second light splitting film, and transmission by the microstructure element array.

2. The optical imaging assembly of claim 1, wherein:

each microstructure element is a dihedral element having two adjacent surfaces forming a right angle; or alternatively

Each microstructure unit is a corner cube element having three mutually perpendicular adjacent surfaces.

3. The optical imaging assembly of claim 1, wherein one of the first and second light splitting films is a polarizing light splitting film and the other is a light intensity light splitting film.

4. An optical imaging assembly according to claim 3, wherein the polarization axis of the polarizing beamsplitter is disposed at an angle of 45 degrees or 135 degrees to the first direction.

5. The optical imaging assembly of claim 1, further comprising a phase retarder disposed between the light modulating component and the second light splitting film.

6. The optical imaging assembly of claim 5, the phase retarder being a quarter-wave plate.

7. The optical imaging assembly of claim 3, wherein the second light splitting film is a polarizing light splitting film and is disposed outside the first surface of the light modulating member or between the first surface of the light modulating member and a light splitting layer.

8. The optical imaging assembly of claim 3, wherein the first light splitting film is a polarizing light splitting film and the second light splitting film is disposed outside the second surface of the light modulating member or between the second surface of the light modulating member and a light splitting layer.

9. An optical imaging assembly according to claim 3, further comprising a polarizer or a combination of a polarizer and a phase retarder disposed outside the second surface of the light modulating member.

10. The optical imaging assembly of claim 3, wherein the optical imaging assembly further comprises: and the linear polaroid or the circular polaroid is used for reducing the reflection of the polarized light splitting film on the ambient light.

11. The optical imaging assembly of claim 1, wherein the spectral layer divides the light modulating component into a first dielectric portion and a second dielectric portion, the first dielectric portion and the second dielectric portion having the same refractive index.

12. The optical imaging assembly of claim 11, wherein the refractive index of the first media portion and the second media portion is between 1.3 and 1.8.

13. The optical imaging assembly of claim 11, wherein a plurality of media are present between the light modulating component and the second light splitting film, the plurality of media having a refractive index that differs from the refractive index of the first media portion and the second media portion by less than 0.3.

14. The optical imaging assembly of claim 11, wherein the first media portion and the second media portion are formed of an isotropic material.

15. The optical imaging assembly of claim 1, wherein the array of microstructure elements is formed along a planar or curved surface.

16. The optical imaging assembly of claim 1, wherein the object plane and the image plane of the optical imaging assembly are disposed substantially symmetrically with respect to the spectral layer.

17. The optical imaging assembly of claim 1, wherein the light modulating component is configured to image in the 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, respectively.

18. The optical imaging assembly of claim 17, wherein the array of microstructure elements is a one-dimensional rectangular grating array and the light modulating means is integral with a lens for modulating the imaging light in the second direction.

19. The optical imaging assembly of claim 17, wherein the imaging optics group comprises one or more lenses.

20. The optical imaging assembly of claim 19, wherein one of the one or more lenses is a second-direction aperture stop of the optical imaging assembly in the second direction.

21. The optical imaging assembly of claim 20, wherein the one lens is a fresnel lens having teeth disposed at equal intervals therebetween.

22. The optical imaging assembly of claim 1, further comprising a one-dimensional grid transmission array, the array of microstructure elements being a one-dimensional orthogonal grating array, the one-dimensional grid transmission array being substantially orthogonal to the one-dimensional orthogonal grating array.

23. The optical imaging assembly of claim 3, wherein said light intensity splitting film is a depolarizing light intensity splitting film, wherein |rs-rp|is less than or equal to 10%.

24. The optical imaging assembly of any of claims 1-23, wherein a spacing between the second light splitting film and the light splitting layer is between 0 and 100 μιη.

25. The optical imaging assembly of any of claims 1-23, wherein the optical imaging system further comprises: and the filter element is positioned between the first light splitting film and the second light splitting film and is used for passing light rays in a preset angle range.

26. An optical imaging module for use in a hover display, the optical imaging module comprising: the optical imaging assembly of any of claims 1-16 and 23-25, and the first array of microstructure elements in the first optical imaging assembly is disposed substantially orthogonal with respect to the second array of microstructure elements in the second optical imaging assembly, and each of the first microstructure elements and the second microstructure elements is a dihedral angle element.

27. A floating display device, comprising:

one or more optical imaging assemblies as claimed in any one of claims 1 to 25 and/or one or more optical imaging modules as claimed in claim 26; and

An image display module configured to emit the image light.

28. The floating display device of claim 27, wherein the image display module is a three-dimensional display.

29. A multi-layer display device comprising:

a floating display device according to claim 27 or 28; and

and a transparent display device disposed optically downstream of the floating display device, wherein a display surface of the transparent display device is located at a different position than a floating image surface.

30. The multi-layer display device of claim 29 wherein the transparent display means comprises a transparent display or is implemented by projecting an image onto a transparent/translucent film.