Suspension optical device, optical module and optical system

Abstract

The invention provides a suspension optical device, an optical module and an optical system, which are used for suspension display. The suspended optical device comprises a focusing layer, a transmission layer and a convergence layer which are sequentially stacked in the direction of an optical axis. The focusing layer comprises a plurality of periodic array focusing units, the convergence layer comprises a plurality of periodic array convergence units, and the plurality of focusing units and the plurality of convergence units are in one-to-one correspondence along the direction of an optical axis; in the focusing unit and the convergence unit which correspond to each other, the focusing unit is used for modulating the incident light, so that the parallel incident light is converged to the same incident convergence point on the incident surface of the transmission layer; the transmission layer modulates the light rays of the incident convergent points to emergent convergent points on the emergent surface of the transmission layer in a one-to-one correspondence manner; and the convergence unit is used for modulating the light rays emitted from the convergent points, so that the light rays at the same emergent convergent point are converged into parallel emergent light rays. The suspension optical device is small in optical loss during suspension imaging.

Description

Suspended optical devices, optical modules and optical systems Technical Field

[0001] The present application relates to the field of display technology, and in particular to a suspended optical device, an optical module, and an optical system. Background Art

[0002] Levitational display is a novel display method that can create stunning floating effects reminiscent of those seen in science fiction films. A common structure for achieving this, as shown in Figure 1, utilizes a set of optical components as a levitation optical device 01. A light source image K is imaged in air without a medium. The resulting image is called a levitation image K'. The levitation image K' is free from any obstructions, allowing the viewer to interact with it. The viewer's physical position can overlap with that of the levitation image. The levitation image K' and the light source image K are symmetrically distributed, with the plane L0 containing the levitation optical device 01 as the axis of symmetry.

[0003] In the existing display technology, the suspended display device suffers from a large amount of light loss during the suspended imaging process, which affects the imaging effect of the suspended display.

[0004] Summary of the Invention

[0005] The present application provides a suspended optical device, an optical module and an optical system, which have low light loss during suspended imaging and can optimize the imaging effect of suspended display.

[0006] In a first aspect, the present application provides a suspended optical device that can be used for a suspended display. The suspended optical device comprises a focusing layer, a transmissive layer, and a converging layer stacked in sequence along an optical axis. The optical axis is the optical axis of the suspended optical device. The transmissive layer has an incident surface and an exit surface, relative to the direction of light. The focusing layer is disposed on the incident surface of the transmissive layer and is used to converge the incident light onto the incident surface of the transmissive layer. After the light enters the transmissive layer from the incident surface, the transmissive layer modulates the light and directs it to the exit surface. The converging layer is disposed on the exit surface of the transmissive layer and is used to direct the light emitted from the exit surface of the transmissive layer into exiting light. During the light transmission process, the focusing layer, the transmissive layer, and the converging layer cooperate to ensure that the incident and exiting light are symmetrical about the transmissive layer. To achieve this effect, the focusing layer includes multiple focusing units, which are periodically arrayed in a direction perpendicular to the optical axis. Correspondingly, the converging layer includes multiple converging units, which are periodically arrayed in a direction perpendicular to the optical axis. The multiple focusing units correspond one-to-one with the multiple converging units. In a pair of corresponding focusing units and convergence units, the focusing unit can focus incident light rays originating from the same pixel onto a single incident convergence point on the incident surface of the transmissive layer. Light rays originating from the same pixel incident on the focusing unit correspond to a single incident convergence point. When the light source image includes light rays from multiple directions, there will be multiple incident convergence points on the incident surface. The transmissive layer can modulate light rays from the incident convergence points on the incident surface onto exit convergence points on the exit surface in a one-to-one correspondence, with each incident convergence point corresponding to a single exit convergence point. Light rays from the exit convergence points on the exit surface enter the convergence unit, which converges the light rays from the same exit convergence point into exit light rays. Each exit convergence point corresponds to a group of exit light rays. A first angle is formed between the incident light rays and the incident surface of the transmissive layer, and this first angle is acute. A second angle is formed between the exit light rays and the exit surface of the transmissive layer, and this second angle is also acute. The opening at the first angle and the opening at the second angle face the same side of the optical axis, and the first and second angles are equal in magnitude.

[0007] In application, the focusing layer can converge the incident light onto the incident surface of the transmission layer, while the convergence layer can converge the light on the exit surface of the transmission layer and finally image the light source image into a suspended image in a symmetrical manner with respect to the transmission layer. The light source image is composed of multiple pixels, and the light emitted by any pixel on the light source image can be incident on multiple focusing units as the incident light. The incident light and the exit light corresponding to the corresponding focusing units and convergence units can be symmetrical with respect to the transmission layer, so that the light emitted from multiple convergence units can form a pixel on the suspended image. Finally, multiple pixels can form a suspended image, ensuring that the suspended image is the same as the light source image. During the entire light transmission process, there is basically no other loss except for the light loss caused by the transmittance of the device material. Therefore, as long as the high transmittance of the device is guaranteed, the light loss can be controlled, the light efficiency of the suspended imaging can be improved, and the effect of optimizing and improving the display of the suspended image can be achieved.

[0008] The multiple focusing units and the multiple converging units can be arranged symmetrically about the transmission layer, that is, along the optical axis of the suspended optical device, the multiple focusing units and the multiple converging units correspond one to one. Within each set of corresponding focusing units and converging units, the optical centers of the focusing units and the converging units are aligned along the optical axis. After the incident light passes through the focusing units, the transmission layer, and the converging units, the resulting outgoing light will be symmetrical with the incident light about the transmission layer.

[0009] Possibly, in the corresponding focusing unit and convergence unit, the distance between the transmissive layer and the focusing unit is equal to the distance between the transmissive layer and the convergence unit, that is, the focusing unit and the convergence unit are symmetrical about the transmissive layer. Such a symmetrical structure is conducive to the realization of floating display.

[0010] The transmission layer is located at 1-2 times the focal length of the focusing unit, and the transmission layer is located at 1-2 times the focal length of the convergence unit. The position of the transmission layer relative to the focusing unit is limited to ensure that the focusing unit can converge the light rays originating from the same pixel in the incident light rays to the same incident convergence point on the incident surface of the transmission layer. The position of the transmission layer relative to the convergence unit is limited to ensure that the convergence unit can converge the light rays at the same exit convergence point on the exit surface of the transmission layer into a group of exit light rays, which are symmetrical with the above-mentioned incident light rays about the transmission layer. Here, the focusing unit and the convergence unit can choose the same structure, the same material, or the same structure and material.

[0011] In some possible implementations, the array period of the multiple focusing units is the same as the array period of the multiple converging units. Possibly, the array period of the multiple focusing units and the array period of the multiple converging units are both 0.3-1 mm. The spacing between the optical axes of any two adjacent focusing units is the array period of the focusing units, and the spacing between the optical axes of any two adjacent converging units is the array period of the converging units.

[0012] In some possible implementations, the transmission layer includes a plurality of transmission units, which are periodically arrayed along a direction perpendicular to the optical axis, and the plurality of transmission units correspond one-to-one to the plurality of focusing units, and the plurality of transmission units also correspond one-to-one to the plurality of convergence units; among the corresponding focusing units, transmission units, and convergence units, the focusing unit is used to modulate the incident light so that the incident light emitted by the same pixel converges to the same incident convergence point on the incident surface of the transmission unit; the transmission unit can modulate the light at the incident convergence point one-to-one to the exit convergence point on the exit surface of the transmission unit; the convergence unit is used to modulate the light at the exit convergence point so that the light at the same exit convergence point converges to the exit light; the incident light and the exit light are symmetrical about the transmission unit. Such a structural design can further precisely modulate the incident light, making the imaging of the suspended image more accurate and reducing the occurrence of stray light and interference light.

[0013] The transmission unit may be a first optical structure having a beam deflection function. The first optical structure may include any one or more combinations of aspherical optical elements, metasurface optical elements, and diffractive optical elements. When the first optical structure is a metasurface optical element or a diffractive optical element, the first optical structure includes a first substrate and a first micro-nanostructure disposed on the first substrate.

[0014] The focusing unit and the convergence unit can both be second optical structures with focusing and imaging functions. The second optical structure can specifically include any one of a spherical optical element, an aspheric optical element, a metasurface optical element, and a diffractive optical element, or a combination of at least two. When the second optical structure is a metasurface optical element or a diffractive optical element, the second optical structure includes a second substrate and a second micro-nanostructure disposed on the second substrate.

[0015] The first micro-nano structure and the second micro-nano structure are both micro-nano structures. The micro-nano structure here is composed of at least two transparent media with different refractive indices, which can modulate light to achieve the effect of light deflection.

[0016] In some possible implementations, the suspended optical device may further include an aperture. Specifically, the aperture may be disposed between the focusing layer and the transmissive layer, between the transmissive layer and the convergent layer, on the side of the focusing layer facing away from the transmissive layer, or on the side of the convergent layer facing away from the transmissive layer. The aperture is used to control the amount of light incident on the suspended optical device and the aberration of the image.

[0017] In a second aspect, the present application further provides an optical module comprising a support member and any of the aforementioned suspended optical devices. The support member can provide support for the suspended optical device, allowing the focusing layer, transmission layer, and convergence layer in the suspended optical device to be stacked sequentially along the optical axis of the device. Of course, the support member does not affect the incidence and emission of light from the suspended optical device.

[0018] In a third aspect, the present application further provides an optical system, which may include a light source image generator and any of the above-mentioned suspended optical devices. The light source image generator is specifically arranged on the side of the focusing layer away from the transmission layer. The light source image generator can generate a light source image. The focusing layer, transmission layer, and convergence layer of the suspended optical device can process the light emitted by the light source image, and ultimately form an image as a suspended image on the side of the convergence layer away from the transmission layer. The suspended image and the light source image are symmetrical about the transmission layer. The light source image generator is a 2D image display or a 3D image display. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG1 is a schematic diagram showing the principle of a suspension display in the prior art;

[0020] FIG2a is a schematic structural diagram of a suspension optical system in the prior art;

[0021] FIG2 b is a schematic diagram showing the principle of a beam splitter in a suspended optical system in the prior art;

[0022] FIG2 c is a schematic diagram showing the structure and principle of a retroreflector in a suspended optical system in the prior art;

[0023] FIG3a is a schematic structural diagram of a suspension optical system in the prior art;

[0024] FIG3 b is a schematic diagram of a dihedral reflection structure of a suspended optical system in the prior art;

[0025] FIG3 c is a schematic diagram showing the principle of a dihedral reflective array of a suspended optical system in the prior art;

[0026] 4a and 4b are schematic structural diagrams of a suspended optical device provided in an embodiment of the present application;

[0027] FIG5a is a schematic structural diagram of a suspended optical device provided in an embodiment of the present application;

[0028] FIG5 b is a schematic structural diagram of a second optical structure in a suspended optical device provided in an embodiment of the present application;

[0029] FIG6a and FIG6b are optical path diagrams of a group of unit structures in a suspended optical device provided in an embodiment of the present application;

[0030] FIG7 is a light path diagram of a suspended optical device provided in an embodiment of the present application;

[0031] 8a and 8b are optical path diagrams of a suspended optical device provided in an embodiment of the present application;

[0032] 9a to 9c are optical path diagrams of a suspended optical device provided in an embodiment of the present application;

[0033] FIG10 is a schematic structural diagram of a suspended optical device provided in an embodiment of the present application;

[0034] FIG11 is a light path diagram of a suspended optical device provided in an embodiment of the present application;

[0035] FIG12 is a schematic structural diagram of a first optical structure in a suspended optical device provided in an embodiment of the present application;

[0036] FIG13a is a schematic structural diagram of a suspended optical device provided in an embodiment of the present application;

[0037] FIG13b is a light path diagram of a suspended optical device provided in an embodiment of the present application;

[0038] 14a to 14d are schematic structural diagrams of a suspended optical device provided in an embodiment of the present application;

[0039] FIG15a is a schematic structural diagram of an optical module provided in an embodiment of the present application;

[0040] FIG15 b is a schematic cross-sectional view of an optical module provided in an embodiment of the present application;

[0041] Figures 16a and 16b are schematic structural diagrams of an optical system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] The suspension display technology can form an image in the air, allowing viewers to see an image floating in the air. In conjunction with Figure 1, the light emitted by the light source image K is processed by the suspension optical device to form a suspension image K'. The ratio of the light energy of the suspension image K' to the light energy of the light source image K is the light efficiency of the suspension optical device. As shown in Figure 2a, a suspension optical system for realizing suspension display is composed of a retroreflector 011 and a beam splitter 012. The plane where the beam splitter 012 is located is L0, and the light source image K and the retroreflector 011 are arranged on the same side of the beam splitter 012. In particular, as shown in Figure 2b, the beam splitter 012 is a semi-transparent and semi-reflective mirror that can transmit and reflect the incident light half-way. The retroreflector 011 has a microstructure array 0111, and the microstructure array 0111 can specifically be a micro-angular reflector (as shown in Figure 2c) or a micro-spherical reflector (not shown here). In Figure 2c, microstructure array 0111 is capable of secondary reflection of a portion of the incident light (e.g., light b1 and light b2), resulting in the outgoing light being parallel to and in the opposite direction of the incoming light. Another portion of the incident light (e.g., light b3) is lost after a single reflection by microstructure array 0111. Combining Figures 2a, 2b, and 2c, light source image generator 013 generates a light source image K within a certain viewing angle range. Light a1 forming light source image K first strikes beam splitter 012. Half of light a2 is transmitted and lost, while the remaining half of light a3 is reflected by the beam splitter onto retroreflector 011. Microstructure array 0111 on retroreflector 011 modulates each incident light beam, ensuring that the modulated beam exits in the same direction as the incident beam. Light a4, after passing through retroreflector 011, passes through beam splitter 012 again. Half of light a5 is reflected and lost, while the remaining half of light a6 is transmitted and forms a suspended image K', which is perceived by the viewer. The virtual image K' is symmetrical with the light source image K about the plane L0 where the beam splitter 012 is located. The optical path principle shown in Figure 2a shows that the light needs to pass through the beam splitter 012 twice, with half of the energy lost each time. The retroreflector 011 also produces energy loss when modulating the light beam. Assuming that the light energy of the light source image K is 100%, the light energy after passing through the beam splitter 012 is 50%. Assuming that the reflectivity of the retroreflector 011 is as high as 97%, the remaining light energy after reflection from the retroreflector 011 is 50% × 97% × 97% ≈ 47%. After passing through the beam splitter 012 again, the remaining light energy of the suspended image K' is only 47% × 50% = 23.5%. It can be seen that when the suspended optical device in Figure 2a performs a suspended display, the light energy loses almost 80%, and the total light efficiency is only about 20%.

[0043] FIG3c is another example of a suspended optical system, in which the suspended optical device for realizing suspended display is composed of a dihedral corner reflector array (DCRA). Referring to FIG3b , the dihedral corner reflector array specifically includes a first reflector array 014 and a second reflector array 015 arranged orthogonally. The first reflector array 014 and the second reflector array 015 can form countless square micro-reflector units (SMR) B. The inner wall of each micro-reflector unit B is coated with a reflective material. As shown in FIG3c , the inner wall of the micro-reflector unit B can perform a secondary reflection on the light c1 so that the outgoing light is symmetrical with the direction of the incident light, the light c2 forms stray light after one or multiple reflections, and the light c3 passes through the gap of the micro-reflector unit B and is lost. Combining Figures 3a and 3c, the light source image generator 013 generates a light source image K within a certain viewing angle range. Light b1 emitted by light source image K is incident on a dihedral reflector array. A portion of light d1 is reflected twice within the dihedral reflector array (see light c1 in Figure 3c), and the emerging light d2 is symmetrical in direction to the incident light b1. A portion of incident light d3 directly passes through the hollow micro-reflector element B and is lost there (see light c3 in Figure 3c). The remaining light is reflected once (see light c2 in Figure 3c) or multiple times within the dihedral reflector array, forming ghost images or stray light. These ghost images and stray light interfere with the suspended image K'. This type of suspended optical device has a complex manufacturing process and exhibits significant light loss. Assuming the light energy of light source image K is 100%, and the light passes through the dihedral reflector array, at least 40% of the light is directly transmitted through the SMRs due to their hollow nature, leaving 60%. Assuming that another 20% of the light undergoes only a single or multiple reflections, forming ghost images and stray light, the remaining 60% - 20% = 40%. Assuming the dihedral reflector array has a reflectivity of 97% per reflection, the resulting light energy of the suspended image K' is only 40% × 97% × 97% ≈ 37%. Therefore, the suspended optical device in Figure 3a loses over 60% of its light energy during the suspended display, resulting in a total light efficiency of less than 40%.

[0044] It can be seen that the existing suspended optical devices suffer from severe light loss during imaging, resulting in very low light efficiency, which is not conducive to suspended imaging. This results in relatively low brightness, clarity, and contrast of the suspended image. These defects also make it difficult to expand the application of suspended display technology. To this end, the embodiments of the present application provide a suspended optical device for improving the light efficiency of suspended display.

[0045] In order to make the purpose, technical solutions and advantages of this application clearer, this application will be further described in detail below with reference to the accompanying drawings.

[0046] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and appended claims of this application, the singular expressions "a", "an", "said", "above", "the", and "this" are intended to also include expressions such as "one or more", unless the context clearly indicates otherwise.

[0047] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in yet other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0048] Referring to Figure 4a, an embodiment of the present application provides a suspended optical device 10 that can be used for suspended display. The suspended optical device 10 has an optical axis P, which is oriented in the direction of the optical axis P. Along the optical axis P, the suspended optical device 10 includes a focusing layer 1, a transmissive layer 2, and a converging layer 3, stacked in sequence. Based on the incident and exit directions of light during use, the transmissive layer 2 has an incident surface e1 and an exit surface e2. That is, light enters the transmissive layer 2 from the incident surface e1 and exits the transmissive layer 2 from the exit surface e2. The plane in which the transmissive layer 2 lies is defined as the first plane L1. The focusing layer 1 is located on the side of the light incident surface e1 of the transmissive layer 2, and the plane in which the focusing layer 1 lies is defined as the second plane L2. The converging layer 3 is located on the side of the light exit surface e2 of the transmissive layer 2, and the plane in which the converging layer 3 lies is defined as the third plane L3. The first plane L1, the second plane L2, and the third plane L3 are all perpendicular to the optical axis P. In application, the focusing layer 1 can converge the incident light onto the incident surface e1 of the transmission layer 2, while the convergence layer 3 can converge the light emitted from the exit surface e2 of the transmission layer 2, and finally image the light source image as a suspended image on the side of the convergence layer 3 away from the transmission layer 2.

[0049] As shown in Figure 4b, the focusing layer 1 includes a plurality of focusing units 11, which are periodically arrayed in a direction perpendicular to the optical axis, and the plane where each focusing unit 11 is located is the second plane L2. The convergence layer 3 includes a plurality of convergence units 31, which are periodically arrayed in a direction perpendicular to the optical axis, and the plane where each convergence unit 31 is located is the third plane L3. Along the optical axis, the plurality of focusing units 11 and the plurality of convergence units 31 correspond one to one. Between the corresponding focusing units 11 and convergence units 31, the line connecting the optical center of the focusing unit 11 and the optical center of the convergence unit 31 is perpendicular to the plane where the transmission layer 2 is located, that is, the optical axis of the focusing unit 11 and the optical axis of the convergence unit 31 are collinear. In Figure 4b, the focusing layer 1 shows five focusing units 11, and correspondingly, the convergence layer 3 shows five convergence units 31. It should be understood that each focusing unit 11 has an optical axis, and each converging unit 31 also has an optical axis. The optical axis of any focusing unit 11 is parallel to the optical axis P of the suspended optical device 10, and the optical axis of any converging unit is also parallel to the optical axis P of the suspended optical device 10. Furthermore, in corresponding focusing units 11 and converging units 31, the optical axis of the focusing unit 11 and the optical axis of the converging unit 31 coincide. The focusing unit 11 can focus the incident light onto the incident surface e1 of the transmissive layer 2, while the converging unit 31 can converge the light on the exit surface e2 of the transmissive layer 2 and emit it as an outgoing light. The outgoing light is symmetrical with the incident light about the transmissive layer 2.

[0050] As shown in Figures 4a and 4b , the focusing layer 1 and the convergence layer 3 are symmetrically arranged with respect to the transmissive layer 2. The distance between the plane L1 of the transmissive layer 2 and the plane L2 of the focusing layer 1 is h1, and the distance between the plane L1 of the transmissive layer 2 and the plane L3 of the convergence layer 3 is h2, with h1 and h2 being equal. The transmissive layer 2 is positioned at 1-2 times the focal length of the focusing unit 11, and at 1-2 times the focal length of the convergence unit 31. For example, the transmissive layer 2 is positioned at 1 times the focal length of the focusing unit 11, and at 1 times the focal length of the convergence unit 31.

[0051] As shown in Figure 4b, the array period of the focusing unit 11 and the convergence unit 31 can be set to be the same, and the range can be 0.3-1mm. Taking the focusing unit 11 as an example, the spacing between the optical axes of any two adjacent focusing units 11 is the array period of the focusing unit 11. It can be inferred that the spacing between the optical axes of any two adjacent convergence units 31 is the array period of the convergence unit 31. Any two adjacent In Figure 4b, two groups of corresponding focusing units 11 and convergence units 31 are used as examples for explanation. In the first group of corresponding focusing units 11 and convergence units 31, the optical axis of the focusing unit 11 and the optical axis of the convergence unit 31 are collinear and set as optical axis S1. In the second group of corresponding focusing units 11 and convergence units 31, the optical axis of the focusing unit 11 and the optical axis of the convergence unit 31 are collinear and set as optical axis S2. The optical axis S1 and the optical axis S2 are respectively parallel to the optical axis P of the suspended optical device 10, and the distance between the optical axis S1 and the optical axis S2 is the array period H. In other words, the array period of the focusing unit 11 and the converging unit 31 is H, and the value range of H is 0.3-1 mm. For example, the array period can be 0.4 mm, 0.6 mm, or 0.9 mm.

[0052] Among them, the focusing unit 11 and the convergence unit 31 are both first optical structures with focusing and imaging functions. For example, if the first optical structure is a microlens, then the focusing layer 1 is equivalent to a microlens array, and the convergence layer 3 is also a microlens array. Specifically, the first optical structure can be any one of a spherical optical element, an aspheric optical element, a metasurface optical element, and a diffraction optical element, or a combination of at least two of these optical elements. As shown in Figure 5a, the focusing unit 11 and the convergence unit 31 are both spherical optical elements. The production technology of spherical optical elements is relatively mature and has been applied to various technical fields of industry and scientific research. Other surface-type optical elements can also be mass-produced with the help of semiconductor processes or nanoimprint processes. Therefore, the processing feasibility of the focusing unit 11 and the convergence unit 31 is relatively high, which is conducive to reducing costs.

[0053] In order to achieve better light transmission effect, the focusing unit 11 and the convergence unit 31 are made of materials with higher light transmittance, such as photoresist. The focusing unit 11 and the convergence unit 31 can have the same structure, the same material, or both the same structure and material.

[0054] In a specific embodiment, when the second optical structure is a metasurface optical element or a diffraction optical element, as shown in Figure 5b, the second optical structure includes a second substrate 41 and a second micro-nano structure 42 disposed on the second substrate 41. The second substrate 41 can specifically be an inorganic transparent material (such as silicon dioxide, silicon carbide), or an organic material (such as polymethyl methacrylate, photoresist). The second micro-nano structure 42 here is composed of at least two transparent media with different refractive indices, exemplified here as a first medium 421 and a second medium 422. For example, the first medium 421 is polymethyl methacrylate (PMMA) and the second medium 422 is air. The first micro-nano structure 42 has a micrometer or nanometer scale characteristic size and is arranged in an array in a specific manner. Taking the metasurface type as an example, the second micro-nano structure 42 is a subwavelength unit. Along the horizontal plane where the second substrate 41 is located, the distance between any two points on the cross section of each second micro-nano structure 42 is less than the wavelength of the incident light. Furthermore, the distance between any two adjacent second micro-nano structures 42 is smaller than the wavelength of the incident light, so that the second micro-nano structures 42 can perform phase modulation on the incident light, thereby achieving an optical path deflection effect.

[0055] Taking a set of corresponding focusing units 11 and convergence units 31 as an example, the corresponding focusing units 11, convergence units 31, and transmission layer 2 are set to form a set of unit structures. Since the focusing unit 11 is small enough and the pixel is far enough away from the focusing unit 11, the incident light M1 emitted by the pixel that can be incident on the focusing unit 11 is approximately parallel. As shown in Figure 6a. A beam of light originating from the same pixel (for the convenience of illustration, the light originating from the same pixel is shown as being parallel to each other) is used as the incident light M1 and is incident from one side of the focusing unit 11. The focusing unit 11 modulates the incident light M1 so that the incident light M1 converges to the same incident convergence point O1 on the incident surface e1 of the transmission layer 2 and enters the transmission layer 2 from the incident convergence point O1. The transmission layer 2 modulates the light at the incident convergence point O1 and modulates this part of the light to the exit convergence point O2 on the exit surface e2 of the transmission layer 2. After emitting from the outgoing convergence point O2, the light rays diverge and enter the convergence unit 31. The convergence unit 31 modulates the light rays emitted from the outgoing convergence point O2 so that the light rays are emitted from the convergence unit 31 in a state that is approximately parallel to each other. The light rays emitted from the convergence unit 31 are the outgoing light rays M2, which are symmetrical with the incident light rays M1 about the transmission layer 2.

[0056] Specifically, please continue to refer to Figure 6a. Along the X direction, the incident light M1 includes light m11, light m12, and light m13. After passing through the focusing unit 11, the transmission layer 2, and the convergence unit 31, the light m11 is emitted as light m21. After passing through the focusing unit 11, the transmission layer 2, and the convergence unit 31, the light m12 is emitted as light m22. After passing through the focusing unit 11, the transmission layer 2, and the convergence unit 31, the light m13 is emitted as light m23. Light m21, light m22, and light m23 constitute the outgoing light M2, and light m23, light m22, and light m21 are arranged in sequence. That is to say, for one focusing unit 11, a group of parallel incident light rays form outgoing light rays after passing through the focusing unit 11, the transmission layer 2, and the convergence unit 31, and the direction of the outgoing light rays is symmetrical with the direction of the incident light rays about the transmission layer 2. Along the X direction, the incident light M1 includes light m11, light m12, and light m13, while the outgoing light M2 includes light m23, light m22, and light m21. The marking order of the incident light M1 is opposite to the marking order of the outgoing light M2 along the X direction. The order of the light represents the information carried by the light. Since the focusing unit 11 is small enough, when the pixel size on the light source image is larger than the focusing unit 11, the information carried by the incident light M1 is the information of the same pixel. At this time, although the light m11, light m12, light m13 and m23, light m22, and light m21 appear to be discontinuous in space, and the order of the outgoing light M2 is opposite to that of the incident light M1, from the perspective of light waves and carrying the same information, the information of the incident light M1 and the outgoing light M2 is exactly the same, and will not affect the inversion of the image information. When the pixel size of the light source image is smaller than the focusing unit 11, the order of the outgoing light rays M2 is reversed from the order of the incident light rays M1. However, the reversed pixels will not have a significant impact from a macroscopic perspective. Alternatively, pre-processing the pixel inversion of the light source image at the light source generator end can avoid the inversion of the outgoing information content. In summary, the periodic array of focusing units 11 and the periodic array of convergence units 31 in the embodiments of the present application, combined with the transmissive layer 2, can image the information of the same pixel onto the same pixel of the suspended image in a manner symmetrical with respect to the transmissive layer 2, thereby achieving the effect of suspended imaging.

[0057] If the incident light includes light from multiple directions, as shown in Figure 6b, the incident light M1 originating from one pixel is exemplified as a group of parallel light, and the incident light M1' originating from another pixel is exemplified as another group of parallel light, and the directions of the incident light M1 and the incident light M1' are different. The incident light M1 and the incident light M1' are incident from one side of the focusing unit 11. The focusing unit 11 modulates the incident light M1 so that the incident light M1 originating from one pixel converges to the same incident convergence point O1 on the incident surface e of the transmission layer 2 and enters the transmission layer 2 from the incident convergence point O1. The focusing unit 11 modulates the incident light M1' so that the incident light M1' originating from the other pixel converges to the same incident convergence point O1' on the incident surface e of the transmission layer 2 and enters the transmission layer 2 from the incident convergence point O1. The transmission layer 2 modulates the light at the incident convergence point O1 and modulates this portion of the light to the exit convergence point O2 on the exit surface e2 of the transmission layer 2. The transmission layer 2 modulates the light at the incident convergence point O1' so that this portion of the light converges to the exit convergence point O2' on the exit surface e2 of the transmission layer 2. After emitting from the exit convergence point O2, the light diverges and enters the convergence unit 31. The convergence unit 31 modulates the light emitted from the exit convergence point O2 so that the light can be emitted from the convergence unit 31 in a state that is approximately parallel to each other (i.e., the exit light M2). The exit light M2 is symmetrical to the incident light M1 with respect to the transmission layer 2. After emitting from the exit convergence point O2', the light diverges and enters the convergence unit 31. The convergence unit 31 modulates the light emitted from the exit convergence point O2' so that the light can be emitted from the convergence unit 31 in a state that is approximately parallel to each other (i.e., the exit light M2'). The direction of the exit light M2' is symmetrical to the direction of the incident light M1' with respect to the transmission layer 2.

[0058] Combining Figures 6a and 6b, it can be seen that in the light transmission process from the incident light to the outgoing light, there is basically no other loss except the light loss caused by the transmittance of each component of the suspended optical device 10 itself. In other words, the suspended optical device 10 provided in the embodiment of the present application has a relatively small loss of light. By setting the focusing layer 1, the transmission layer 2, and the convergence layer 3 to materials with high transmittance, the light efficiency of the entire device can be improved. For example, if the light transmittance of the focusing layer 1, the transmission layer 2, and the convergence layer 3 is set to 92%, the total light efficiency of the suspended optical device 10 is 92%×92%×92%≈78%. This light efficiency data is significantly improved compared to the prior art.

[0059] For the entire suspended optical device 10, the focusing layer 1 is composed of a periodic array of multiple focusing units 11, and the converging layer 3 is also composed of a periodic array of multiple converging units 31. As shown in Figure 7, for each set of corresponding focusing units 11 and converging units 31, it can be considered that each set of corresponding focusing units 11 and converging units 31 can, in conjunction with the transmission layer 2, process a portion of the incident light into outgoing light, with the direction of the outgoing light being symmetrical with the direction of the incident light about the transmission layer 2. As long as the focusing units 11 and converging units 31 are configured to be small enough so that the corresponding focusing units 11 and converging units 31 can suspend and display sufficiently fine light, for example, suspending and displaying a point of light as a suspended point, the outgoing light can be considered symmetrical with the incident light about the transmission layer 2 on a macroscopic scale.

[0060] The suspended optical device 10 is applied to a suspended display, as shown in FIG8a , where the light source image A is a 2D image, and the light source image A is composed of countless pixels, each of which emits a wide light beam at a certain angle. For example, pixel Q on the light source image A emits a wide light beam F at the angle shown in the figure. The wide light beam F can be regarded as being composed of countless fine light beams f in various directions. Each fine light beam f is incident on the suspended optical device 10, and is sequentially processed by the focusing layer 1, the transmission layer 2, and the convergence layer 3 to emit a wide light beam F' composed of multiple fine light beams f'. The wide light beam F' is concentrated at the pixel Q' of the suspended image A', and the pixel Q' is symmetrical with the pixel Q about the transmission layer 2. Specifically, as shown in FIG8b , a fine light beam f in the incident light corresponds to a group of corresponding focusing units 11 and convergence units 31. Taking a group of approximately mutually parallel light rays corresponding to a fine light beam f as an example, in each group of mutually corresponding fine light beams f, focusing units 11, and convergence units 31, the light rays of the fine light beam f are first converged by the focusing unit 11 to the same incident convergence point on the incident surface e1 of the transmission layer 2 (not shown here), and the transmission layer 2 performs a specific deflection modulation on the light rays, modulating the light rays to the same exit convergence point on the exit surface e2 of the transmission layer 2 (not shown here). The light rays emitted from the same exit convergence point are modulated again by the convergence unit 31, and finally the light rays emitted from the convergence unit 31 are restored to beams that are approximately mutually parallel, and these beams can be regarded as fine light beams f'. The fine light beams f' are symmetrical with the fine light beams f about the transmission layer 2. All the fine light beams f' form a wide light beam F shown in Figure 8a, which converge to a point in the air, which is the suspended pixel Q' in the suspended image A'. Countless pixels such as pixel Q' form the suspended image A'.

[0061] In Figures 8a and 8b, the light source image A is a 2D image, and the suspended image A' formed by the suspended optical device 10 is also a 2D image. Based on the above embodiments, the suspended optical device 10 provided in the present embodiment can symmetrically (with respect to the transmissive layer 2) suspend any point on the light source image A to form a suspended image A'.

[0062] In some embodiments, as shown in FIG9a , the light source image B is a 3D image, and the light source image B is composed of countless light source pixels, and each pixel on the light source image B emits a wide light beam at a certain angle. For example, the pixel R on the light source image B emits a wide light beam G at the angle shown in the figure. The wide light beam G can be regarded as being composed of countless fine light beams g in various directions. Each fine light beam g is incident on the suspended optical device 10, and after being processed by the focusing layer 1, the transmission layer 2, and the convergence layer 3 in sequence, it is emitted as a wide light beam G' composed of multiple fine light beams g'. The wide light beam G' is concentrated at the pixel R' of the suspended image B', and the pixel R' is symmetrical with the pixel R about the transmission layer 2. Countless pixels such as pixel R' constitute the suspended image B'. The optical path principle of the fine light beam g being processed by the focusing layer 1, the transmission layer 2, and the convergence layer 3 can be referred to as shown in FIG8b , which will not be repeated here.

[0063] Continuing with the suspended optical device 10 shown in FIG9b , compared to the suspended optical device 10 shown in FIG9a , this suspended optical device 10 is tilted 45° relative to the horizontal plane. The structures of the focusing layer 1, the transmission layer 2, and the convergence layer 3 in the suspended optical device 10 can be referred to in FIG9a and will not be further described here. As shown in FIG9c , a corresponding set of focusing units 11 and convergence units 31 are provided for a beamlet g in an example of incident light. Taking a set of approximately parallel light rays corresponding to a beamlet g as an example, in each corresponding set of beamlets g, focusing units 11, and convergence units 31, the light rays of the beamlet f are first converged by the focusing unit 11 to the same incident convergence point on the incident surface e1 of the transmission layer 2 (not shown here). The transmission layer 2 then performs a specific deflection modulation on the light rays, modulating the light rays to the same exit convergence point on the exit surface e2 of the transmission layer 2 (not shown here). The light rays emitted from the same exit convergence point are further modulated by the convergence unit 31, ultimately returning the light rays emitted from the convergence unit 31 to approximately parallel beams. These beams can be considered as fine beams g'. The fine beams g' are symmetrical with the fine beam g about the transmission layer 2. All the fine beams g' form the wide beam F shown in Figure 9b, which converges to a single point in space, which is the suspended pixel R' in the suspended image B'. Countless pixels similar to pixel R' form the suspended image B'.

[0064] In some embodiments, as shown in FIG10 , the transmission layer 2 includes a plurality of transmission units 21. The plurality of transmission units 21 are periodically arrayed along a direction perpendicular to the optical axis, and the plane where each transmission unit 21 is located is a first plane L1 (the first plane L1 can be shown in FIG4 a ). Along the optical axis, the plurality of transmission units 21, the plurality of focusing units 11, and the plurality of convergence units 31 correspond one to one. In FIG10 , the focusing layer 1 shows five focusing units 11, the convergence layer 3 shows five convergence units 31, and the transmission layer 2 shows five transmission units 21. Along the optical axis, one focusing unit 11 corresponds to one convergence unit 31, and one focusing unit 11 also corresponds to one transmission unit 21. It should be understood that each focusing unit 11 has an optical axis, each convergence unit 31 also has an optical axis, and each transmission unit 21 also has an optical axis. The optical axis of any focusing unit 11 is parallel to the optical axis P of the suspended optical device 10. The optical axis of any converging unit 31 is also parallel to the optical axis P of the suspended optical device 10. The optical axis of any transmitting unit 21 is also parallel to the optical axis P of the suspended optical device 10. Furthermore, in corresponding focusing units 11, transmitting units 21, and converging units 31, the optical axes of the focusing unit 11, the transmitting unit 21, and the converging unit 31 coincide. This structural design further refines the processing of incident light, resulting in more precise imaging of the suspended image and reducing stray light and interference light.

[0065] Among them, as shown in Figure 10, the array period of the focusing unit 11, the transmission unit 21, and the convergence unit 31 can be set to be the same, and the range of the array period can be 0.3-1mm. Taking the focusing unit 11 as an example, the distance between the optical axes of any two adjacent focusing units 11 is the array period of the focusing unit 11. As shown in Figure 10, two groups of corresponding focusing units 11, transmission units 21, and convergence units 31 are used as an example for explanation. In the first group of corresponding focusing units 11, transmission units 21, and convergence units 31, the optical axis of the focusing unit 11, the optical axis of the transmission unit 21, and the optical axis of the convergence unit 31 are collinear and set as optical axis S1. In the second group of corresponding focusing units 11, transmission units 21, and convergence units 31, the optical axis of the focusing unit 11, the optical axis of the transmission unit 21, and the optical axis of the convergence unit 31 are collinear and set as optical axis S2. The distance between the optical axis S1 and the optical axis S2 is the array period H, that is, the array period of the focusing unit 11, the transmission unit 21, and the convergence unit 31 is H, and the value range of H is 0.3-1 mm. For example, H is selected to be 0.4 mm, 0.6 mm, or 0.9 mm.

[0066] 10 , the focusing unit 11 can focus the incident light onto the incident surface e1 of the transmissive layer 2, while the converging unit 31 can converge the light on the exit surface e2 of the transmissive layer 2 and then emit it as an outgoing light. The optical path principle can be shown in FIG11 . For each corresponding set of focusing units 11, transmissive units 21, and converging units 31, it can be assumed that each corresponding set of focusing units 11, transmissive units 21, and converging units 31 processes a portion of the incident light into outgoing light, with the outgoing light direction being symmetrical with the incident light direction about the transmissive layer 2. As long as the focusing units 11, transmissive units 21, and converging units 31 are sufficiently small, so that the corresponding focusing units 11, transmissive units 21, and converging units 31 can suspend and display sufficiently fine light, for example, suspending and displaying a point of light as a suspended point, the macroscopically inconsistency between the outgoing light image and the incident light image can be ignored, and thus the outgoing light and the incident light can be considered symmetrical about the transmissive layer 2.

[0067] The transmission unit 21 is a first optical structure with a beam deflection function. Therefore, the transmission layer 2 is equivalent to a first optical structure array. Specifically, the first optical structure can be any one of an aspheric optical element, a metasurface optical element, and a diffractive optical element, or a combination of at least two of these optical elements. When the first optical structure is a metasurface optical element or a diffractive optical element, its structure can be shown in FIG12 . The first optical structure includes a first substrate 51 and a first micro-nano structure 52 disposed on the first substrate 51. The first substrate 51 can be an inorganic transparent material (e.g., silicon dioxide, silicon carbide) or an organic material (e.g., polymethyl methacrylate, photoresist). The first micro-nano structure 52 here is composed of at least two transparent media with different refractive indices, exemplified here as a third medium 521 and a fourth medium 522. For example, the third medium 521 is polymethyl methacrylate (PMMA) and the fourth medium 522 is air. The first micro-nano structure 52 has micrometer- or nanometer-scale characteristic dimensions and is arranged in an array in a specific manner. Taking the metasurface type as an example, the first micro-nanostructures 52 are subwavelength units. Along the horizontal plane of the first substrate 51, the distance between any two points on the cross-section of each first micro-nanostructure 52 is less than the wavelength of the incident light. Furthermore, the spacing between any two adjacent first micro-nanostructures 52 is less than the wavelength of the incident light. This allows the first micro-nanostructures 52 to phase modulate the incident light, thereby achieving an optical deflection effect.

[0068] In the above-mentioned embodiment, a plurality of focusing units 11 and a plurality of converging units 31 correspond one to one along the optical axis direction, and the suspended image formed after the incident light is processed by the suspended optical device 10 is symmetrical with the light source image about the transmission layer 2. In other embodiments, as shown in FIG13a, between the corresponding focusing units 11 and converging units 31, perpendicular to the optical axis direction, the optical axis T1 of the focusing unit 11 and the optical axis T3 of the converging unit 31 may have an offset of z along the direction perpendicular to the optical axis. Correspondingly, the optical path diagram of the incident light and the outgoing light can be shown in FIG13b. Taking a set of corresponding focusing units 11 and converging units 31 as an example, along the X direction perpendicular to the optical axis, the optical axis T3 of the converging unit 31 has an offset of z relative to the optical axis T1 of the focusing unit 11. Taking a beam of light originating from a single pixel (for ease of illustration, the light originating from the same pixel is shown as being parallel here) as the incident light M1, the incident light M1 forms a first angle β1 with the surface of the focusing unit 11 facing away from the transmissive layer 2. This first angle β1 is acute, and the opening of the first angle β1 faces the left side of the illustrated device structure. The incident light M1 enters from one side of the focusing unit 11. The focusing unit 11 modulates the incident light M1 so that the incident light M1 converges to a single incident convergence point O1 on the incident surface e1 of the transmissive layer 2, and then enters the transmissive layer 2 from this incident convergence point O1. The transmissive layer 2 modulates the light at this incident convergence point O1, modulating this portion of the light to an exit convergence point O2 on the exit surface e2 of the transmissive layer 2. After emitting from the exit convergence point O2, the light diverges and enters the converging unit 31. The converging unit 31 modulates the light emitted from the exit convergence point O2 so that the light can be emitted from the converging unit 31 in a state that is approximately parallel to each other. The light emitted from the convergence unit 31 is the outgoing light M2, and a second angle β2 is formed between the outgoing light M2 and the surface of the convergence unit 31 facing away from the transmission layer 2, and the second angle β2 is also an acute angle. The second angle β2 is also an acute angle, and the opening of the second angle β2 is also facing the left side of the device structure shown in the figure. Taking the optical axis P as a reference, it can be considered that the opening of the first angle β1 and the opening of the second angle β2 are facing the same side of the optical axis P. Moreover, the second angle β2 is equal to the first angle β1. There may be an offset of w between the outgoing light M2 and the incident light M1 along the X direction. Although the incident light M1 and the outgoing light M2 have a certain position offset in the direction of the optical axis, from the perspective of the light wave angle and carrying the same information, the information of the incident light M1 and the outgoing light M2 is exactly the same, and the information of the same pixel can be imaged into the same pixel of the suspended image, achieving the effect of suspended imaging.

[0069] Based on the suspended optical device 10 shown in Figure 4a, as shown in Figures 14a to 14d, an embodiment of the present application further provides a suspended optical device 10 having an aperture 6. Specifically, the aperture 6 can be disposed on the side of the converging layer 3 facing away from the transmissive layer 2, as shown in Figure 14a. Alternatively, the aperture 6 can be disposed on the side of the focusing layer 1 facing away from the transmissive layer 2, as shown in Figure 14b. Alternatively, the aperture 6 can be disposed between the converging layer 3 and the transmissive layer 2, as shown in Figure 14c. Alternatively, the aperture 6 can be disposed between the transmissive layer 2 and the focusing layer 1, as shown in Figure 14d. The presence of the aperture 6 controls the amount of light passing through the suspended optical device 10. Specifically, the aperture 6 is used to control the amount of light incident on and the aberration of the image formed by the suspended optical device 10. The placement of the aperture 6 does not affect its functionality.

[0070] In summary, when the suspended optical device 10 provided in the embodiment of the present application is applied to a suspended display, the light emitted by each pixel on the light source image can be incident on different focusing units 11 of the focusing layer 1, and each focusing unit 11 can modulate the incident light so that the incident light originating from the same pixel can converge to the same incident convergence point on the incident surface e1 of the transmission layer 2, and the incident light originating from the same pixel corresponds to one incident convergence point. The transmission layer 2 can modulate the light at the same incident convergence point on the incident surface e1 to the exit convergence point on the exit surface e2. Each convergence unit 31 can modulate the light at the exit convergence point so that the light at the same exit convergence point can converge into exit light rays that are approximately parallel to each other, and each group of exit light rays that are approximately parallel to each other corresponds to one exit convergence point. Among them, the periodic array structure of the focusing unit 11 and the periodic array structure of the convergence unit 31 can process the light of each pixel on the light line emitted by the light source image, so that the outgoing light can be symmetrical with the incident light about the transmission layer 2. The outgoing light can form a suspended image, ensuring that the suspended image has the same information as the light source image. When multiple convergence units 31 and multiple focusing units 11 are selected to correspond one to one along the optical axis, the outgoing light can also be symmetrical with the incident light about the transmission layer 2. During the entire light transmission process, there is basically no other loss except for the light loss caused by the transmittance of the device material. Therefore, as long as the high transmittance of the device is guaranteed, the light loss can be controlled, the light efficiency of the suspended imaging can be improved, and the clarity and contrast of the suspended image display can be optimized.

[0071] Based on the above-mentioned suspended optical device 10, the embodiment of the present application also provides an optical module 100. As shown in Figure 15a, the optical module 100 includes a support member 20 and any one of the suspended optical devices 10 provided in the above-mentioned embodiments. The suspended optical device 10 is exemplified here as a circle. The support member 20 is annular with a hollow in the middle. The suspended optical device 10 is arranged in the middle hollow position of the support member 20, that is, the support member 20 provides support for the suspended optical device 10 from the circumferential edge of the suspended optical device 10, and the hollow in the middle of the support member 20 does not affect the incidence and emission of light. Figure 15b shows a schematic diagram of the cross-sectional structure of the optical module 100. The circumferential edges of the focusing layer 1, the transmission layer 2 and the convergence layer 3 in the suspended optical device 10 are all fixed to the support member 20, and the focusing layer 1, the transmission layer 2 and the convergence layer 3 are stacked in sequence along the direction of the optical axis P.

[0072] In addition, an embodiment of the present application also provides an optical system. As shown in Figures 16a and 16b, the optical system includes a light source image generator 200 and any of the above-mentioned optical modules 100. The light source image generator 200 is disposed on the side of the focusing layer 1 of the suspended optical device 10 away from the transmission layer 2. The light emitted by the light source image A generated by the light source image generator can pass through the focusing layer 1, the transmission layer 2, and the convergence layer 3 in sequence to form a suspended image. This optical system has a wide range of application scenarios, including but not limited to public places such as elevators, restaurants, and banks, as well as private places such as private cars and home desktops. For example, when this optical system is applied to button suspension displays in public places, it can achieve contactless interaction, which has the advantages of being safer, more hygienic, and more private. When this optical system is applied to virtual decorations or car elves suspension displays in private cars, it will bring a more shocking, cooler, and more personalized user experience. When this optical system is applied to home desktop suspension displays, the three-dimensional suspension display and zero-distance interactive operation can enhance the gaming experience and fun, and realize the naked eye virtual and real fusion function.

[0073] As shown in FIG16a , the light source image generator 200 is a 2D image display, such as a liquid crystal display (LCD), an organic light-emitting diode (OLED) screen, or a projection screen. The light source image A generated by the light source image generator is a 2D image. The light source image A is composed of countless pixels, each of which emits a wide light beam at a certain angle. For example, pixel Q on the light source image A emits a wide light beam F at the angle shown. The wide light beam F can be considered to be composed of countless fine light beams f in various directions. Each fine light beam f is incident on the suspended optical device 10, and after being processed by the focusing layer 1, the transmission layer 2, and the convergence layer 3, it is emitted as a wide light beam F' composed of multiple fine light beams f'. The wide light beam F' is concentrated at pixel Q' of the suspended image A', and pixel Q' is symmetrical with pixel Q about the transmission layer 2. Countless pixels such as pixel Q' constitute the suspended image A'. The light processing of the countless fine light beams f by the focusing layer 1, the transmission layer 2, and the convergence layer 3 can be referred to as shown in FIG8b , and will not be repeated here.

[0074] As shown in Figure 16a, the light source image generator 200 is a 3D image display, and the light source image B generated by the light source image generator 20 is a 3D image. The light source image B is composed of countless pixels, and each pixel on the light source image B emits a wide light beam at a certain angle. For example, the pixel R on the light source image B emits a wide light beam G at the angle shown in the figure. The wide light beam G can be regarded as composed of countless fine light beams g in various directions. Each fine light beam g is incident on the suspended optical device 10, and after being processed by the focusing layer 1, the transmission layer 2 and the convergence layer 3 in sequence, it is emitted as a wide light beam G' composed of multiple fine light beams g'. The wide light beam G' is concentrated at the pixel R' of the suspended image B', and the pixel R' is symmetrical with the pixel R about the transmission layer 2. Countless pixels such as pixel R' constitute the suspended image B'. The optical path principle of the fine light beam g being processed by the focusing layer 1, the transmission layer 2 and the convergence layer 3 can be referred to as shown in Figure 8b, and will not be repeated here.

[0075] Since the suspended optical device 10 has a high light efficiency, the optical system provided in the embodiment of the present application can image the image (including 2D images and 3D images) produced by the light source image generator into a suspended image through the transmission of the suspended optical device 10, and the brightness, clarity, and contrast of the suspended image are relatively high, which can achieve a good suspended display effect.

[0076] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A suspended optical device, characterized in that: include: A focusing layer, a transmission layer, and a convergence layer are sequentially stacked along the optical axis; the transmission layer has an incident surface facing the focusing layer and an exit surface facing the convergence layer; The focusing layer comprises a plurality of focusing units, which are periodically arrayed along a direction perpendicular to the optical axis; the converging layer comprises a plurality of converging units, which are periodically arrayed along a direction perpendicular to the optical axis; and the plurality of focusing units correspond to the plurality of converging units in a one-to-one manner; In the corresponding focusing unit and the convergence unit, the focusing unit is used to modulate the incident light so that the incident light emitted by the same pixel converges to the same incident convergence point on the incident surface of the transmission layer; the transmission layer is used to modulate the light at the incident convergence point to the exit convergence point on the exit surface of the transmission layer in a one-to-one correspondence; the convergence unit is used to modulate the light at the exit convergence point so that the light at the same exit convergence point converges to the exit light; A first angle is formed between the incident light and the incident surface of the transmission layer, and a second angle is formed between the exiting light and the exit surface of the transmission layer; the opening of the first angle and the opening of the second angle are facing the same side of the optical axis; the first angle and the second angle are both acute angles, and the first angle and the second angle are equal in size.

2. The suspended optical device according to claim 1, wherein: The plurality of focusing units and the plurality of converging units are symmetrical with respect to the transmission layer, so that the incident light and the outgoing light are symmetrical with respect to the transmission layer.

3. The suspended optical device according to claim 1 or 2, characterized in that: The transmission layer includes a plurality of transmission units, the plurality of transmission units are periodically arrayed along a direction perpendicular to the optical axis, and the plurality of transmission units correspond one-to-one to the plurality of focusing units; The transmission unit modulates the light at the incident convergence point to the exit convergence point on the exit surface of the transmission unit in a one-to-one correspondence.

4. The suspended optical device according to claim 3, wherein: The transmission unit is a first optical structure with a light beam deflection function.

5. The suspended optical device according to claim 4, wherein: The first optical structure includes any one or more combinations of aspherical optical elements, metasurface optical elements, and diffractive optical elements.

6. The suspended optical device according to claim 5, wherein: When the first optical structure is a metasurface optical element or a diffractive optical element, the first optical structure includes a first substrate and a first micro-nano structure arranged on the first substrate.

7. The suspended optical device according to any one of claims 1 to 6, characterized in that: The focusing unit and the convergence unit are both second optical structures with focusing and imaging functions.

8. The suspended optical device according to claim 7, wherein: The second optical structure includes any one of a spherical optical element, an aspherical optical element, a metasurface optical element, and a diffractive optical element, or a combination of at least two of them.

9. The suspended optical device according to claim 8, wherein: When the second optical structure is a metasurface optical element or a diffractive optical element, the second optical structure includes a second substrate and a second micro-nano structure arranged on the second substrate.

10. The suspended optical device according to any one of claims 1 to 9, characterized in that: The distance between the transmission layer and the focusing layer is equal to the distance between the transmission layer and the convergence unit.

11. The suspended optical device according to claim 10, wherein: The transmission layer is located at 1-2 times the focal length of the focusing unit, and the transmission layer is located at 1-2 times the focal length of the convergence unit.

12. The suspended optical device according to any one of claims 1 to 11, wherein: The array period of the plurality of focusing units is the same as the array period of the plurality of converging units.

13. The suspended optical device according to claim 12, wherein: The array period of the plurality of focusing units and the array period of the plurality of converging units are both 0.3-1 mm.

14. The suspended optical device according to any one of claims 1 to 13, wherein: Also includes the aperture; Along the optical axis, the aperture is located between the focusing layer and the transmission layer; or, the aperture is located between the transmission layer and the convergence layer; or, the aperture is located on the side of the focusing layer away from the transmission layer; or, the aperture is located on the side of the convergence layer away from the transmission layer.

15. An optical module, characterized in that: A device comprising a support and a suspended optical device according to any one of claims 1 to 14; The focusing layer, the transmission layer and the convergence layer are fixed to the support member in sequence along the optical axis direction.

16. An optical system, characterized in that It comprises a light source image generator and the optical module as claimed in claim 15; the light source image generator is arranged on a side of the focusing layer away from the transmission layer to generate a light source image.

17. The optical system according to claim 16, wherein: The light source image generator is a 2D image display or a 3D image display.

Images