An image combiner and near-eye display system

Abstract

The application provides an image combiner and a near-eye display system, wherein the image combiner comprises: a metasurface element and a light control element; the metasurface element is configured to reflect imaging light at a smaller reflection angle and to transmit at least part of light in a visible light band; the light control element is located on a side of the metasurface element away from the imaging light and is configured to transmit at least part of light in the visible light band and to control at least part of the light in the visible light band transmitted through the light control element and the metasurface element to be free of aberration. The image combiner and the near-eye display system provided by the embodiment of the application have a reflection angle of the imaging light smaller than an incident angle, can reduce the thickness of the image combiner, have a small volume, can realize light path conversion in a small space volume, reduce the volume and weight of the image combiner and the design and processing difficulty, and can save cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of near-eye display, in particular to an image combiner and a near-eye display system. BACKGROUND

[0002] The existing MR (Mixed Reality) / AR (Augmented Reality) etc. mainly includes an image combiner in the form of a free-form surface and an image combiner in the form of an optical waveguide. However, no matter which form is used, the imaging light path and the external environment light path enter the human eye at the same time, and the human eye sees the superimposed image of the two.

[0003] Since the image combiner needs to simultaneously process the near-eye display light of the projection light path and the aberration of the correction environment light path, there are many difficulties in design and processing. For example, in terms of design, it is difficult to optimize the free-form surface, and it is difficult to correct the "rainbow effect" in the optical waveguide; in terms of processing, it is difficult to process the free-form surface, and it is difficult to reduce the center thickness, resulting in discomfort when wearing; the optical waveguide scheme needs to use complex structures such as inclined tooth gratings, which increases the processing difficulty and increases the cost of mass production.

[0004] Some schemes use multiple small wedge-shaped mirrors to realize the light path conversion of the imaging light, which can achieve miniaturization to some extent, but the structure is still relatively complex, the processing difficulty is large, the cost of mass production is high, and it is not suitable for large-scale promotion. SUMMARY

[0005] To solve the above problems, the purpose of the embodiments of the present application is to provide an image combiner and a near-eye display system.

[0006] In a first aspect, the embodiments of the present application provide an image combiner, comprising: a metasurface element and a light control element;

[0007] The metasurface element is configured to be able to reflect imaging light for imaging and to be able to transmit at least part of light in the visible light band; the incidence angle of the imaging light incident to the metasurface element is greater than the reflection angle of the imaging light;

[0008] The light control element is located on the side of the metasurface element away from the imaging light, and is configured to be able to transmit at least part of the light in the visible light band and to control at least part of the light in the visible light band transmitted through the light control element and the metasurface element to be free of aberration.

[0009] In a possible implementation, the metasurface element comprises: a plurality of modulation units arranged along an x direction; the modulation units comprise at least one nanostructure; the x direction is a direction in a plane in which the metasurface element is located, and distances between the modulation units at different positions in the x direction and an observation plane used for observing an image of an imaging light ray are different;

[0010] The modulation units are configured to perform phase modulation on the imaging light ray incident at a first angle, and reflect the modulated imaging light ray at a second angle; the first angle is greater than the second angle.

[0011] In a possible implementation, a phase modulated by the modulation unit satisfies:

[0012]

[0013] wherein, denotes a phase modulated by the modulation unit at a position x, θ r denotes the second angle, θ i denotes the first angle, k denotes a wave number, denotes a preset constant phase.

[0014] In a possible implementation, the metasurface element further comprises: a substrate; the substrate is transparent in the visible light waveband;

[0015] The plurality of modulation units are arranged on one side of the substrate;

[0016] The light control element is located on a side of the substrate away from the modulation units.

[0017] In a possible implementation, a sum of the first angle and the second angle is 90°±Δα; Δα denotes an angle less than a preset threshold.

[0018] In a possible implementation, the light control element comprises: a phase compensator;

[0019] The phase compensator is configured to perform phase modulation on at least part of the light in the visible light waveband, and a phase modulated by the phase compensator can compensate for a phase modulated by the metasurface element on the at least part of the light in the visible light waveband that passes through.

[0020] In a possible implementation, the phase compensator comprises at least one refractive lens with a free-form surface on at least one side; or,

[0021] The phase compensator is a superlens.

[0022] In a possible implementation, in the case where the phase compensator is a metalens, the phase compensator is arranged to be attached to the metasurface element.

[0023] In a possible implementation, the light control element comprises a first polarizer.

[0024] The first polarizer is configured to convert at least part of the light rays in the visible light band that pass through the first polarizer into light rays in a first polarization state.

[0025] The metasurface element is configured to be capable of reflecting the imaging light rays in a second polarization state, and the metasurface element performs geometric phase modulation on the incident light rays in the second polarization state; the first polarization state is different from the second polarization state.

[0026] In a possible implementation, the first polarization state and the second polarization state are orthogonal to each other.

[0027] In a second aspect, an embodiment of the present application further provides a near-eye display system, comprising an image source and an image combiner as described above.

[0028] The image source is configured to emit imaging light rays capable of being emitted to the image combiner.

[0029] The image combiner is located on the light-emitting side of the image source, and the light control element of the image combiner is located on the side of the metasurface element of the image combiner that is away from the image source.

[0030] In a possible implementation, the reflection angle of the metasurface element reflecting the imaging light rays is the same as the setting angle of the metasurface element, and the setting angle of the metasurface element is the included angle between the metasurface element and an observation surface used for observing the image of the imaging light rays.

[0031] In a possible implementation, the setting angle of the metasurface element is less than or equal to 25°.

[0032] In a possible implementation, the near-eye display system further comprises a relay optical system.

[0033] The relay optical system is located between the image source and the image combiner, and is configured to adjust the light rays emitted by the image source to be emitted to the image combiner.

[0034] In a possible implementation, the relay optical system comprises a light deflection element.

[0035] The light deflection element is configured to reflect the incident imaging light rays to the image combiner.

[0036] In a possible implementation, the image source is configured to emit the imaging light rays in a second polarization state.

[0037] In a possible implementation, the image source comprises a second polarizer.

[0038] The second polarizer is configured to convert the imaging light rays into light rays in the second polarization state before the imaging light rays are incident on the metasurface element.

[0039] In a possible implementation, the image source comprises a light source and an image generator.

[0040] The light source is configured to emit light rays.

[0041] The image generator is located on the light-emitting side of the light source and is configured to convert the light rays emitted by the light source into imaging light rays.

[0042] In a possible implementation, the light source is configured to emit, in time division, first light rays in a first waveband, second light rays in a second waveband, and third light rays in a third waveband; the first waveband, the second waveband, and the third waveband are different wavebands in the visible light waveband, and the metasurface element is capable of reflecting at least part of the light rays in the first waveband, the second waveband, and the third waveband.

[0043] In a possible implementation, the light source comprises a first monochromatic light source, a second monochromatic light source, a third monochromatic light source, a first beam splitter, and a second beam splitter.

[0044] The first monochromatic light source is configured to emit the first light rays, the second monochromatic light source is configured to emit the second light rays, and the third monochromatic light source is configured to emit the third light rays.

[0045] The first beam splitter is located on the light-emitting side of the first monochromatic light source and is configured to adjust the first light rays emitted by the first monochromatic light source to have the same direction of emergence as the third light rays.

[0046] The second beam splitter is located on the light-emitting side of the second monochromatic light source and is configured to adjust the second light rays emitted by the second monochromatic light source to have the same direction of emergence as the third light rays.

[0047] In a possible implementation, the first beam splitter and the second beam splitter are both dichroic mirrors.

[0048] The first beam splitter and the second beam splitter are both located on the principal optical axis of the light source, and the first beam splitter is closer to the light-emitting side of the light source than the second beam splitter.

[0049] The first beam splitter is configured to reflect the light rays of the first wave band and transmit the light rays of the second wave band and the third wave band.

[0050] The second beam splitter is configured to reflect the light rays of the second wave band and transmit the light rays of the third wave band.

[0051] The wavelengths of the first wave band, the second wave band and the third wave band increase or decrease in turn.

[0052] In a possible implementation, the light source further includes a third beam splitter.

[0053] The third beam splitter is located on the light emitting side of the third monochromatic light source and is used to adjust the emitting direction of the third light rays emitted by the third monochromatic light source.

[0054] In a possible implementation, the light source includes a fourth monochromatic light source, a fifth monochromatic light source and a fluorescent disc.

[0055] The fourth monochromatic light source and the fifth monochromatic light source are both used to emit the first light rays.

[0056] The fluorescent disc is located on the light emitting side of the fourth monochromatic light source and is used to convert the first light rays emitted by the fourth monochromatic light source into the second light rays and the third light rays and emit the second light rays and the third light rays; the first light rays emitted by the fifth monochromatic light source are emitted.

[0057] The wavelength of the first wave band is smaller than the wavelengths of the second wave band and the third wave band.

[0058] In a possible implementation, the light source further includes a fourth beam splitter and a fifth beam splitter.

[0059] The fourth beam splitter and the fifth beam splitter are both located on the light emitting side of the fluorescent disc.

[0060] The fourth beam splitter is used to adjust the second light rays emitted by the fluorescent disc to have the same emitting direction as the first light rays emitted by the fifth monochromatic light source.

[0061] The fifth beam splitter is used to adjust the third light rays emitted by the fluorescent disc to have the same emitting direction as the first light rays emitted by the fifth monochromatic light source.

[0062] In a possible implementation, the fourth beam splitter and the fifth beam splitter are both dichroic mirrors.

[0063] The fourth beam splitter and the fifth beam splitter are both located on the main optical axis of the light source, and the fifth beam splitter is closer to the light emitting side of the light source than the fourth beam splitter.

[0064] The fourth beam splitter is configured to reflect light rays of the second wave band and transmit light rays of the first wave band.

[0065] The fifth beam splitter is configured to reflect light rays of the third wave band and transmit light rays of the first wave band and the second wave band.

[0066] The wavelength of the second wave band is smaller than the wavelength of the third wave band.

[0067] In a possible implementation, the image generator comprises a digital micromirror device, or

[0068] The image generator comprises a beam expander and a spatial light modulator; the beam expander is located on the light exit side of the light source and is configured to expand the light rays emitted by the light source; and the spatial light modulator is located on the light exit side of the beam expander and is configured to convert the light rays emitted by the beam expander into imaging light rays.

[0069] In the scheme provided in the first aspect of the above-mentioned embodiment of the present application, the imaging light rays can be reflected and at least part of the ambient light in the visible light wave band can be transmitted, so that the imaging light rays and the ambient light can enter the human eye together; the hyper-surface element modulates the incident imaging light rays, so that the reflection angle of the imaging light rays is smaller than the incident angle, the angle between the hyper-surface element and the plane in which the human eye is located is small, the thickness of the image combiner can be reduced, the volume is small, and the light path conversion can be realized in a small space; and the hyper-surface element based on the hyper-surface technology itself has the characteristics of being thin and easy to process, the volume and weight of the image combiner are reduced, and the design and processing difficulty is reduced, so that the cost can be saved. The light control element can cooperate with the modulation effect of the hyper-surface element, so that the ambient light is still unmodulated after passing through the light control element and the hyper-surface element, the ambient light can enter the human eye without aberration, and the user can watch the external environment without distortion.

[0070] In order to make the above-mentioned purpose, characteristics and advantages of the present application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0071] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating any inventive labor.

[0072] Figure 1 A first structural schematic diagram of an image combiner provided by an embodiment of the present application is shown;

[0073] Figure 2 A top view structural schematic diagram of the metasurface element provided by the embodiment of the present application is shown;

[0074] Figure 3 A side view structural schematic diagram of the metasurface element provided by the embodiment of the present application is shown;

[0075] Figure 4 A second structural schematic diagram of the image combiner provided by the embodiment of the present application is shown;

[0076] Figure 5 A third structural schematic diagram of the image combiner provided by the embodiment of the present application is shown;

[0077] Figure 6 A fourth structural schematic diagram of the image combiner provided by the embodiment of the present application is shown;

[0078] Figure 7 A fifth structural schematic diagram of the image combiner provided by the embodiment of the present application is shown;

[0079] Figure 8 A first structural schematic diagram of the near-eye display system provided by the embodiment of the present application is shown;

[0080] Figure 9 A second structural schematic diagram of the near-eye display system provided by the embodiment of the present application is shown;

[0081] Figure 10 A third structural schematic diagram of the near-eye display system provided by the embodiment of the present application is shown;

[0082] Figure 11 A fourth structural schematic diagram of the near-eye display system provided by the embodiment of the present application is shown;

[0083] Figure 12A A first structural schematic diagram of the image source provided by the embodiment of the present application is shown;

[0084] Figure 12B A second structural schematic diagram of the image source provided by the embodiment of the present application is shown;

[0085] Figure 13A A third structural schematic diagram of the image source provided by the embodiment of the present application is shown;

[0086] Figure 13B A fourth structural schematic diagram of the image source provided by the embodiment of the present application is shown;

[0087] Figure 14A A fifth structural schematic diagram of the image source provided by the embodiment of the present application is shown;

[0088] Figure 14BA sixth structural schematic diagram of an image source provided by an embodiment of the present application is shown.

[0089] Figure 15 A detailed structural schematic diagram of a near-eye display system provided by an embodiment of the present application is shown.

[0090] Figure 16A A phase distribution diagram of a metasurface element in Embodiment 1 is shown.

[0091] Figure 16B A phase distribution diagram of a phase compensator in Embodiment 1 is shown.

[0092] Figure 17A A phase distribution diagram of a metasurface element in Embodiment 2 is shown.

[0093] Figure 17B A phase distribution diagram of a phase compensator in Embodiment 2 is shown.

[0094] Icon:

[0095] 10-metasurface element, 20-light control element, 30-image source, 40-relay optical system, 11-modulation unit, 12-substrate, 21-phase compensator, 22-first polarizer, 31-light source, 32-image generator, 33-second polarizer, 301-first monochromatic light source, 302-second monochromatic light source, 303-third monochromatic light source, 304-first beam splitter, 305-second beam splitter, 306-third beam splitter, 311-fourth monochromatic light source, 312-fifth monochromatic light source, 313-fluorescent carousel, 314-fourth beam splitter, 315-fifth beam splitter, 321-digital micromirror device, 322-broadener, 323-spatial light modulator, 324-mirror, 325-transflective prism, 41-light deflection element, 42-refractive lens, 43-superlens, 1-glasses leg. DETAILED DESCRIPTION

[0096] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0097] In addition, the terms "first", "second", etc. are used only for the purpose of description, and should not be understood as indicating or implying relative importance or implying the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0098] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0099] The embodiment of the present application provides a kind of image combiner, see Figure 1 As shown, the image combiner includes: super surface element 10 and light control element 20.Super surface element 10 is configured to be able to reflect imaging light A for imaging, and be able to pass at least part of light B in the visible light band;The incidence angle θ i Of imaging light incident to super surface element 10 is greater than the reflection angle θ r Of imaging light.A light control element 20 is located on the side of super surface element 10 away from imaging light A, and is configured to be able to pass at least part of light B in the visible light band, and control at least part of light B in the visible light band that passes through light control element 20 and super surface element 10 is free of aberration.

[0100] The image combiner can provide an image to the human eye, and allow external ambient light to enter the human eye, so that the human eye can see the image and external objects at the same time. As Figure 1 Shown, imaging light A can be imaged within eyebox, so that the user located in the eyebox can view the image formed by the imaging light A;And, external ambient light (such as Figure 1 Light B in it) can also be incident to the position where the human eye is located, so that the user in the eyebox can see the formed image and external objects at the same time.

[0101] In this embodiment of the invention, the image combiner includes a metasurface element 10 designed and fabricated based on metasurface technology. The metasurface element 10 has a transmissive-reflective function, capable of reflecting imaging light A used for imaging, thereby reflecting the imaging light A to the location of the human eye. Furthermore, the metasurface element 10 can also transmit light B, which is light in the visible light band; for example, a portion of the visible light in ambient light can pass through the metasurface element 10. Since a superlens itself has a certain transmissive-reflective effect, the metasurface element 10 can be a superlens to achieve the transmissive-reflective function. Alternatively, a transmissive-reflective film can be provided on the surface of the metasurface element 10, for example, a transmissive-reflective film can be provided on the side of the metasurface element 10 near the light control element 20 to enhance the transmissive-reflective effect. This embodiment does not limit this approach.

[0102] Normally, the metasurface element 10 reflects the imaging ray A in the direction of human eye observation. However, to avoid the human eye directly observing the device that emits the imaging ray A, the direction of the imaging ray A incident on the metasurface element 10 differs significantly from the direction of human eye observation. If the metasurface element 10 performs a traditional reflection function, it will result in a thicker overall image combiner. For example, the imaging ray A incident on the metasurface element 10 may be perpendicular to the direction of human eye observation (e.g., ...). Figure 1 As shown in the diagram, the angle between the metasurface element 10 and the direction of human eye observation needs to be 45°, resulting in a relatively thick overall image combiner. However, in this embodiment of the invention, the metasurface element 10 can reflect light at a smaller angle; that is, the light incident on the metasurface element 10 has a reflection angle smaller than the angle of incidence. For example... Figure 1 As shown, the incident angle of the imaging ray A incident on the metasurface element 10 is θ. i The metasurface element 10 can be positioned at an incident angle θ smaller than the incident angle θ. i The reflection angle θ r The imaging ray A is reflected.

[0103] Because the incident angle of the imaging light rays incident on the metasurface element 10 is greater than the reflection angle, the metasurface element 10 and the plane where the human eye is located (e.g., Figure 1 When the angle between the plane containing the eyebox (which is the observation plane used to observe the image) is small, the imaging ray A incident from the side can still be reflected to the location of the human eye, thus enabling imaging directly in front of the human eye. Because the angle between the metasurface element 10 and the plane containing the human eye can be relatively small, the overall thickness of the image combiner (thickness in the observation direction) is small, reducing the volume of the image combiner. Specifically, the angle between the metasurface element 10 and the plane containing the human eye is less than 45°; for example, the angle is less than 25°, specifically 20°, 10°, etc.

[0104] In the embodiment of the present application, the metasurface element 10 with transreflective function also has a certain modulation effect on the directly incident ambient light, resulting in aberration of the ambient light transmitted by the metasurface element 10, and the user cannot normally view the external environment through the metasurface element 10. In the embodiment, the light control element 20 is arranged to make the ambient light entering the human eye be aberration-free. Specifically, the light control element 20 is arranged on the side of the metasurface element 10 away from the imaging light A, so that the reflected imaging light A will not be reflected to the human eye again after passing through the light control element 20, and will not affect the imaging of the imaging light A. The ambient light (such as the light B shown in Figure 1 The ambient light from the outside (such as the light B shown in

[0105] It should be noted that in the embodiment of the present application, the aberration of the ambient light incident on the human eye is small enough, that is, the ambient light is considered to be "aberration-free", and it is not required that the aberration of the ambient light is absolutely zero, as long as the user can normally view the external things. For example, if the aberration of the ambient light is less than a preset threshold, the ambient light is considered to be aberration-free.

[0106] The image combiner provided by the embodiment of the present application can reflect the imaging light and transmit at least part of the ambient light in the visible light band, so that the imaging light and the ambient light can enter the human eye together. The metasurface element 10 modulates the incident imaging light, so that the reflection angle of the imaging light is smaller than the incident angle. The angle between the metasurface element 10 and the plane where the human eye is located is small, which can reduce the thickness of the image combiner, and the volume is small, and the light path conversion can be realized in a small space. Moreover, the metasurface element 10 based on the metasurface technology is thin and easy to process, which reduces the volume and weight of the image combiner, and the design and processing difficulty, and can save costs. The light control element 20 can cooperate with the modulation effect of the metasurface element 10, so that the ambient light transmitted through the light control element 20 and the metasurface element 10 is still unmodulated, and the ambient light can enter the human eye without aberration, so that the user can view the external environment without distortion.

[0107] Optionally, as shown in Figure 2 The metasurface element 10 includes a plurality of modulation units 11 arranged in the x direction. The x direction is one direction in the plane where the metasurface element 10 is located, and the distance between the modulation units 11 at different positions in the x direction and the observation surface for observing the image of the imaging light is different. The modulation unit 11 is configured to phase-modulate the imaging light incident at a first angle and reflect the modulated imaging light at a second angle. The first angle is greater than the second angle.

[0108] In this embodiment of the invention, the imaging ray A incident on the metasurface element 10 and the observation position of the human eye are relatively fixed; for example, when the image combiner is applied to AR glasses, the image source position emitting the imaging ray A is fixed, generally located on the temple or the side of the lens, and the position of the human eye relative to the AR glasses is also fixed; in this embodiment, the metasurface element 10 is mainly used to reduce the emission angle of the imaging ray A in the plane where the imaging ray A and the observation position are located; specifically, the x-direction is set, which is a direction in the plane where the metasurface element 10 is located, and also a direction in the plane where the imaging ray A and the observation position are located. Figure 1 As shown, Figure 1 The direction corresponding to the metasurface element 10 shown can be the x-direction, in which the distance between the modulation unit 11 at different positions in the metasurface element 10 and the observation surface is different. For example, if the image combiner is used as a lens for AR glasses, the x-direction can be basically the direction between the left and right eyes.

[0109] The modulation units 11 within the metasurface element 10 are arranged along the x-direction; such as Figure 2 As shown, the x-direction is the left-right direction, and multiple modulation units 11 are arranged in a left-right distribution. The imaging ray A is incident on the modulation unit 11 at a first angle. After being modulated by the modulation unit 11, the imaging ray A is reflected at a second angle; that is, the incident angle of the imaging ray A is the first angle, and the reflection angle is the second angle; as shown above, the incident angle of the imaging ray A is greater than the reflection angle, that is, the first angle is greater than the second angle. Figure 1 In, θ i This can be represented by the first angle, θ. r This can represent the second angle. The modulation unit 11 may include a nanostructure, forming a metasurface element 10 similar to a grating structure; or, as... Figure 2 As shown, the modulation unit 11 may also include multiple nanostructures, which are arranged in a direction perpendicular to the x-direction within the modulation unit 11. Figure 2 The nanostructure is represented by a circle.

[0110] Optionally, the phase modulated by the modulation unit 11 satisfies:

[0111]

[0112] in, θ represents the phase modulated by modulation unit 11 located at position x. r θ represents the second angle. i This represents the first angle, and k represents the wave number. This indicates a preset constant phase.

[0113] In the embodiment of the present application, for the modulation unit 11 distributed along the x direction, since the incident angle is greater than the reflection angle, the two light beams parallel incident to the metasurface element 10 have a phase difference between the reflected light beams of the two light beams satisfies:

[0114]

[0115] where Δx represents the distance of the two light beams in the x direction; when Δx approaches 0, the following formula can be obtained:

[0116]

[0117] Based on the above formula (3), the above formula (1) can be obtained by integral operation. The preset arbitrary value can be 0, π / 2, etc., and the embodiment does not limit this. If the modulation unit 11 includes a plurality of nanostructures, the phase distribution of each nanostructure can be the same, and the phase modulated by the nanostructure satisfies the above formula (1). In the embodiment of the present application, the metasurface element 10 sets the phase distribution along the x direction, which can simply reduce the reflection angle and is simple in design.

[0118] Optionally, the sum of the first angle and the second angle is 90°±Δα; Δα represents an angle less than a preset threshold, that is, the imaging light A incident to the metasurface element 10 and the imaging light A reflected by the metasurface element 10 are substantially perpendicular. For example, the preset threshold can be 20°, and the specific value can be 10°, 5°, etc.

[0119] In addition, optionally, as shown in Figure 1 and Figure 3 The metasurface element 10 further includes a substrate 12; the substrate 12 is transparent in the visible light waveband. The plurality of modulation units 11 are arranged on one side of the substrate 12; and the light control element 20 is located on the side of the substrate 12 away from the modulation unit 11.

[0120] In the embodiment of the present application, the metasurface element 10 uses the substrate 12 transparent in the visible light waveband, so that the external environment light can normally pass through the substrate 12 after passing through the light control element 20. In order to avoid the substrate 12 directly reflecting the imaging light A, the modulation unit 11 is located on the side of the substrate 12 close to the imaging light A, and the light control element 20 is located on the side of the substrate 12 away from the modulation unit 11, so that the imaging light A can be modulated by the modulation unit 11 and then reflected.

[0121] On the basis of any of the above embodiments, the light control element 20 can realize the non-diffractive incidence of ambient light to the human eye by phase compensation or conversion of ambient light characteristics. Specifically, if at least part of the light B in the visible light band transmits through the metasurface element 10, the metasurface element 10 modulates the phase of the light B, and the light control element 20 can have a phase compensation function; or if the metasurface element 10 itself does not have a modulation effect on the light with certain characteristics in the visible light band, the light control element 20 can convert the ambient light into light with the characteristics, which is part of the light B in the visible light band, and the light B will not be modulated by the metasurface element 10 when transmitting through the metasurface element 10, so that the human eye can also observe the non-diffractive light B.

[0122] Specifically, as shown in Figure 4 the light control element 20 includes a phase compensator 21; the phase compensator 21 is configured to modulate the phase of at least part of the light B in the visible light band, and the phase modulated by the phase compensator 21 can compensate for the phase modulated by the metasurface element 10 on at least part of the light B in the visible light band that transmits through the metasurface element 10.

[0123] In the embodiment of the application, the external ambient light enters the phase compensator 21, at least part of the light can transmit through the phase compensator 21, the light transmitted through the phase compensator 21 can be referred to as light B, which is at least part of the light in the visible light band; and the phase compensator 21 applies a phase to the light B, that is, the phase modulated by the phase compensator 21 is When the light B transmits through the metasurface element 10, the metasurface element 10 applies a phase to the light B, that is, the phase modulated by the metasurface element 10 on at least part of the light B in the visible light band that transmits through the metasurface element 10 is The two phases are complementary to form an afocal system, so that the light B entering the human eye is non-diffractive.

[0124] Specifically, the phase of the phase compensator 21 satisfies:

[0125]

[0126] Wherein, mod() represents the modulo function.

[0127] For example, as shown in Figure 4 the phase compensator 21 includes a refractive lens with at least one side being a free-form surface, and the phase modulation is realized by using the surface of the free-form surface; as shown in Figure 4 the refractive lens has a plane on the outside and a free-form surface on the inside (close to the metasurface element 10).

[0128] Or, as shown inFigure 5 As shown, the phase compensator 21 is a superlens, and a phase distribution of the superlens can realize the phase compensation function; for example, the phase distribution of the superlens satisfies the above formula (4).

[0129] In addition, optionally, referring to Figure 6 As shown, in the case where the phase compensator 21 is a superlens, the phase compensator 21 is arranged in close contact with the super-surface element 10. For example, the phase compensator 21 and the super-surface element 10 can share the same substrate 12, and the nanostructures of the two are respectively located on the two sides of the substrate 12, so that the volume of the image combiner is smaller and more lightweight.

[0130] Optionally, referring to Figure 7 As shown, the light control element 20 includes: a first polarizer 22. The first polarizer 22 is configured to convert at least part of the light rays in the visible light band that pass through the first polarizer 22 into light rays of a first polarization state; the super-surface element 10 is configured to be capable of reflecting imaging light rays of a second polarization state, and the super-surface element 10 performs geometric phase modulation on the incident light rays of the second polarization state; the first polarization state is different from the second polarization state.

[0131] In the embodiment of the present application, the super-surface element 10 is a geometric phase super-surface, which can modulate the phase of the light rays of the second polarization state and does not modulate the phase of light rays of other polarization states; when the imaging light rays A of the second polarization state are incident on the super-surface element 10, the super-surface element 10 can perform geometric phase modulation on the imaging light rays A of the second polarization state and reflect the imaging light rays A of the second polarization state to the human eye. The first polarizer 22 can convert ambient light into light rays of a first polarization state (this process does not introduce aberration), for example, the first polarizer 22 can only transmit light rays of the first polarization state in the visible light band, so that the light rays B that pass through the first polarizer 22 and reach the super-surface element 10 are light rays of the first polarization state. When the light rays B of the first polarization state pass through the super-surface element 10, since the super-surface element 10 does not modulate the phase of the light rays of the first polarization state, the ambient light finally reaching the human eye is only light rays of the first polarization state, which is still aberration-free.

[0132] To ensure the imaging effect, the first polarization state and the second polarization state are orthogonal. For example, the first polarization state is linear polarization of a first polarization direction, and the second polarization state is linear polarization of a second polarization direction, the first polarization direction and the second polarization direction are perpendicular; or the first polarization state is left-handed circular polarization, and the second polarization state is right-handed circular polarization; or the first polarization state is right-handed circular polarization, and the second polarization state is left-handed circular polarization. The embodiment does not limit the specific mode of the two polarization states.

[0133] The embodiment of the present application also provides a near-eye display system, referring to Figure 8As shown, the near-eye display system comprises an image source 30 and an image combiner provided by any of the above embodiments, i.e. the near-eye display system comprises a metasurface element 10 and a light control element 20, Figure 8 An example is shown in which the light control element 20 comprises a phase compensator 21. In this example, the image source 30 is configured to emit imaging light rays capable of being emitted towards the image combiner, such as the imaging light rays A described above; the image combiner is located on the light emitting side of the image source 30, and the light control element 20 of the image combiner is located on the side of the metasurface element 10 of the image combiner that is away from the image source 30.

[0134] In the embodiments of the present application, the image combiner allows the imaging light rays to be incident on the metasurface element 10 at a large incident angle, and the volume of the image combiner is small. For example, as shown in Figure 8 As shown, when the near-eye display system is applied to AR glasses, the image source 30 can be located on the temple 1, and the image combiner can be used as a lens of the glasses. Even if the thickness of the image combiner is small, the imaging light rays emitted by the image source 30 can still be incident on the image combiner at a large incident angle and be reflected by the image combiner to the human eye.

[0135] Optionally, in order to make the imaging light rays reflected by the image combiner consistent with the viewing direction of the human eye, the reflection angle θ r of the imaging light rays reflected by the metasurface element 10 is the same as the setting angle of the metasurface element 10; wherein the setting angle of the metasurface element 10 is the included angle between the metasurface element 10 and the viewing surface used to view the image of the imaging light rays; as shown in Figure 8 The setting angle is the included angle between the metasurface element 10 and the plane in which the eye movement range is located. If the imaging light rays incident on the metasurface element 10 are perpendicular to the viewing direction of the human eye, then the imaging light rays incident on the metasurface element 10 are also perpendicular to the imaging light rays reflected by the metasurface element 10.

[0136] Optionally, the setting angle is the above-mentioned included angle between the metasurface element 10 and the plane in which the human eye is located. In order to ensure that the thickness of the image combiner is small, the setting angle of the metasurface element 10 is less than or equal to 25°. For example, the setting angle is 20°, 10°, etc.

[0137] In addition, optionally, as shown in Figure 8 The near-eye display system further comprises a relay optical system 40; the relay optical system 40 is located between the image source 30 and the image combiner and is configured to adjust the light rays emitted by the image source 30 to be emitted towards the image combiner.

[0138] In the embodiments of the present application, when the near-eye display system is applied to wearable devices such as AR glasses, due to the limited volume of the wearable devices, the structure frame of the wearable devices can be effectively utilized by adjusting the imaging light rays emitted by the image source 30 using the relay optical system 40. For example, as shown inFigure 8 As shown, the relay optical system 40 may include a refractive lens 42 and / or a superlens 43 to adjust the imaging light; or, the relay optical system 40 may also include a 4f lens group to achieve functions such as image magnification.

[0139] Optionally, such as Figure 8 As shown, the relay optical system 40 includes a light deflecting element 41, which is configured to reflect incident imaging light rays to an image combiner. In this embodiment, the light deflecting element 41 can be used to reflect imaging light rays emitted from the image source 30 located at the temple 1 to the image combiner located at the lens.

[0140] In embodiments of the present invention, such as Figure 8 As shown, the light control element 20 can be a phase compensator 21 in the form of a superlens. Furthermore, the near-eye display system can also employ the aforementioned... Figure 6 The image combiner shown is described in the diagram. The structure of this near-eye display system can be found in [reference needed]. Figure 9 As shown; or, the near-eye display system may also employ the above-described... Figure 4 The image combiner shown is described in the diagram. The structure of this near-eye display system can be found in [reference needed]. Figure 10 As shown.

[0141] Alternatively, the near-eye display system may also employ the above-mentioned... Figure 7 The image combiner shown, namely the light control element 20, includes a first polarizer 22. In this case, the image source 30 is configured to emit imaging light of a second polarization state. In this embodiment of the invention, the image source 30 can emit imaging light of a second polarization state, such that the imaging light A incident on the metasurface element 10 is of the second polarization state, thereby enabling aberration-free ambient light to enter the human eye under the action of the first polarizer 22.

[0142] Optionally, the image source 30 can be a conventional display capable of emitting light with a specific polarization state, such as a liquid crystal display (LCD), which emits linearly polarized light for imaging. Alternatively, see also... Figure 11 As shown, the image source 30 includes a second polarizer 33; the second polarizer 33 is configured to convert the imaging light into a second polarization state before the imaging light reaches the metasurface element 10. In this embodiment of the invention, the second polarizer 33 is used to generate imaging light in a second polarization state, resulting in a better polarization state of the imaging light and effectively avoiding ghosting problems.

[0143] Based on any of the above embodiments, see Figure 8 As shown, the image source 30 includes a light source 31 and an image generator 32; the light source 31 is configured to emit light; the image generator 32 is located on the light-emitting side of the light source 31 and is configured to convert the light emitted by the light source 31 into imaging light.

[0144] In the embodiment of the present application, the light source 31 is a backlight, which emits light required by the image generator 32 when imaging; the image generator 32 can convert the light emitted by the light source 31 into imaging light. For example, the image generator 32 can be a liquid crystal panel, and the image source 30 can be a liquid crystal display. In the case where imaging light of a second polarization state needs to be generated, the second polarizer 33 can be located between the light source 31 and the image generator 32, or on the light-emitting side of the image generator 32; as shown in the figure, the second polarizer 33 can be embedded in the relay optical system 40, and the position of the second polarizer 33 is not limited in the embodiment. Figure 11

[0145] Alternatively, the light source 31 emits light of different wavebands at different times to realize imaging by using the visual dwell effect. Specifically, the light source 31 is configured to emit first light of a first waveband, second light of a second waveband and third light of a third waveband at different times; the first waveband, the second waveband and the third waveband are different wavebands in the visible light waveband, and the super surface element 10 can reflect at least part of the light in the first waveband, the second waveband and the third waveband.

[0146] In the embodiment of the present application, the light source 31 can emit at least three kinds of light at different times, i.e. the first light, the second light and the third light, and the duration of each beam of light can be determined by the refresh rate of the near-eye display system, which can be the refresh rate of the image generator 32. For example, for a near-eye display system with a refresh rate of 120 Hz, the duration of each beam of light is 8.33 milliseconds; each three beams of light (including the first light, the second light and the third light) can form one frame of image, i.e. one frame of image can be generated every 25 milliseconds, and the frame rate of the image displayed by the near-eye display system is 40 Hz.

[0147] The super surface element 10 can have a modulation effect on at least part of the light in the first waveband, the second waveband and the third waveband, and can reflect the light in the three wavebands to the human eye at a smaller reflection angle. For example, the super surface element 10 can be a multi-wavelength chromatic aberration correction super surface, which can correct the chromatic aberration of the light in the first waveband, the second waveband and the third waveband, and can ensure the imaging effect.

[0148] Alternatively, the image generator 32 includes a digital micromirror device 321. Or, the image generator 32 includes a beam expander 322 and a spatial light modulator 323; the beam expander 322 is located on the light-emitting side of the light source 31 and is configured to expand the light emitted by the light source 31; the spatial light modulator 323 is located on the light-emitting side of the beam expander 322 and is configured to convert the light emitted by the beam expander 322 into imaging light.

[0149] ​The digital micromirror device (DMD) 321 is an array composed of multiple high-speed digital light-reflecting switches. For example, the DMD consists of many small aluminum mirrors, the number of which is determined by the display resolution, with one small mirror corresponding to one pixel. Imaging an object onto the DMD, and utilizing its pixel-level controllable characteristics and high-speed flipping frequency, each image point is scanned sequentially, achieving high-speed point scanning imaging. The spatial light modulator (SLM) 323 can be a liquid crystal spatial light modulator or a metasurface-based spatial light modulator, etc., and this embodiment does not limit this. The beam expander 322 expands the emitted imaging light beam, thereby expanding the laser beam into a uniform and easily imaged beam, facilitating imaging by the spatial light modulator 323.

[0150] Optionally, the first, second, and third bands can be one of the red, green, and blue light bands, respectively, meaning that projection imaging can be achieved using the three primary colors of light: red, green, and blue; the following... Figures 12A-14B In the diagram, R, G, and B represent red light, green light, and blue light, respectively.

[0151] Optionally, see Figure 12A and Figure 12B As shown, the light source 31 includes a first monochromatic light source 301, a second monochromatic light source 302, a third monochromatic light source 303, a first beam splitter 304, and a second beam splitter 305. The first monochromatic light source 301 is used to emit a first light ray, the second monochromatic light source 302 is used to emit a second light ray, and the third monochromatic light source 303 is used to emit a third light ray. The first beam splitter 304 is located on the light-emitting side of the first monochromatic light source 301 and is used to adjust the first light ray emitted by the first monochromatic light source 301 to be in the same direction as the third light ray. The second beam splitter 305 is located on the light-emitting side of the second monochromatic light source 302 and is used to adjust the second light ray emitted by the second monochromatic light source 302 to be in the same direction as the third light ray.

[0152] In this embodiment of the invention, the light source 31 includes a first monochromatic light source 301, a second monochromatic light source 302, and a third monochromatic light source 303 capable of operating in a time-division manner, thereby emitting a first ray, a second ray, and a third ray in a time-division manner; wherein, after the first ray emitted by the first monochromatic light source 301 and the second ray emitted by the second monochromatic light source 302 are adjusted by the first beam splitter 304 and the second beam splitter 305 respectively, the first ray, the second ray, and the third ray can be emitted in the same direction; for example Figure 12A As shown, all three types of light rays are emitted from bottom to top; or as... Figure 12B As shown, all three rays are emitted from left to right. For example, the first ray, the second ray, and the third ray are coaxial.

[0153] like Figure 12AAs shown in the figure, the image generator 32 comprises a digital micro-mirror device 321, by controlling the deflection of the mirror at the corresponding position in the digital micro-mirror device 321, the light emitted by the light source 31 can be converted into the imaging light capable of imaging. As Figure 12A As shown in the figure, the image generator 32 can also comprise a trans-reflective prism 325, using the trans-reflective function to generate the imaging light of the required exit direction; as Figure 12A As shown in the figure, the imaging light from left to right can be generated. Alternatively, as Figure 12B As shown in the figure, the image generator 32 comprises a beam expander 322 and a spatial light modulator 323; the light emitted by the light source 31 is expanded by the beam expander 322 and then irradiates the spatial light modulator 323, thereby generating the imaging light A capable of imaging.

[0154] Optionally, as Figure 13A Figure 13B As shown in the figure, the light source 31 also comprises a third beam splitter 306; the third beam splitter 306 is located on the light emitting side of the third monochromatic light source 303, and is used for adjusting the exit direction of the third light emitted by the third monochromatic light source 303. In the embodiment of the present application, the first monochromatic light source 301, the second monochromatic light source 302 and the third monochromatic light source 303 can be arranged side by side, and the propagation directions of the light are adjusted by using the first beam splitter 304, the second beam splitter 305 and the third beam splitter 306, so that the three can be emitted in the same direction.

[0155] Optionally, the first beam splitter 304 and the second beam splitter 305 are both dichroic mirrors. As Figures 12A to 13B As shown in the figure, the first beam splitter 304 and the second beam splitter 305 are both located on the main optical axis of the light source 31, and the first beam splitter 304 is closer to the light emitting side of the light source 31 than the second beam splitter 305. The first beam splitter 304 is configured to reflect the light of the first waveband and transmit the light of the second waveband and the third waveband; the second beam splitter 305 is configured to reflect the light of the second waveband and transmit the light of the third waveband; wherein the wavelengths corresponding to the first waveband, the second waveband and the third waveband increase or decrease in turn.

[0156] In the embodiment of the present application, the wavelengths corresponding to the first waveband, the second waveband and the third waveband increase in turn, for example, the three wavebands are blue waveband, green waveband and red waveband in turn; or, the wavelengths corresponding to the first waveband, the second waveband and the third waveband are smaller in turn, for example, as Figures 12A to 13B As shown in the figure, the three wavebands are red waveband, green waveband and blue waveband in turn. According to this way of setting, the appropriate dichroic mirror can be conveniently selected.

[0157] For example, Figures 12A to 13BThe first monochromatic light source 301 is used to emit red light, the second monochromatic light source 302 is used to emit green light, and the third monochromatic light source 303 is used to emit blue light. At this time, the first beam splitter 304 only needs to be capable of reflecting red light and light with a wavelength greater than the red wavelength, and transmitting a wavelength less than the red wavelength (including the green wavelength and the blue wavelength); similarly, the second beam splitter 305 only needs to be capable of reflecting green light and light with a wavelength greater than the green wavelength, and transmitting a wavelength less than the green wavelength (including the blue wavelength). The third beam splitter 306 can be a dichroic mirror capable of reflecting blue light, or a common mirror, and the present embodiment does not limit this.

[0158] Optionally, the first monochromatic light source 301, the second monochromatic light source 302, and the third monochromatic light source 303 are narrow-band lasers or narrow-band light-emitting diodes. The ratio of the bandwidth of the monochromatic light source to the center wavelength is less than a predetermined value (for example, 0.1, 0.03, etc.), and the monochromatic light source can be considered to be a narrow-band light source.

[0159] Optionally, referring to Figure 14A and Figure 14B The light source 31 includes a fourth monochromatic light source 311, a fifth monochromatic light source 312, and a fluorescent disc 313; the fourth monochromatic light source 311 and the fifth monochromatic light source 312 are both used to emit first light; the fluorescent disc 313 is located on the light-emitting side of the fourth monochromatic light source 311 and is used to convert the first light emitted by the fourth monochromatic light source 311 into second light and third light and emit the second light and the third light; the first light emitted by the fifth monochromatic light source 312 is emitted. The wavelength of the first wavelength band is less than the wavelength of the second wavelength band and the third wavelength band.

[0160] In the embodiment of the present application, the first wavelength band is the smallest wavelength band of the three wavelength bands; for example, for RGB three primary color light, the first wavelength band is the blue light band. The fluorescent disc 313 can excite light with a larger wavelength, and the second light and the third light with a larger wavelength band are generated based on the fluorescent disc 313.

[0161] Optionally, as shown in Figure 14A and Figure 14B The light source 31 further includes a fourth beam splitter 314 and a fifth beam splitter 315. The fourth beam splitter 314 and the fifth beam splitter 315 are both located on the light-emitting side of the fluorescent disc 313; the fourth beam splitter 314 is used to adjust the emission direction of the second light emitted by the fluorescent disc 313 to be the same as the emission direction of the first light emitted by the fifth monochromatic light source 312; and the fifth beam splitter 315 is used to adjust the emission direction of the third light emitted by the fluorescent disc 313 to be the same as the emission direction of the first light emitted by the fifth monochromatic light source 312.

[0162] In the embodiment of the present application, the fourth beam splitter 314 and the fifth beam splitter 315 are similar to the first beam splitter 304 and the second beam splitter 305 in the above embodiment, and can adjust the converted second light and third light to have the same direction of emission as the first light emitted by the fifth monochromatic light source 312.

[0163] Alternatively, the fourth beam splitter 314 and the fifth beam splitter 315 can also be dichroic mirrors. Similar to the first beam splitter 304 and the second beam splitter 305 described above, as shown in Figure 14A and Figure 14B , the fourth beam splitter 314 and the fifth beam splitter 315 are both located on the main optical axis of the light source 31, and the fifth beam splitter 315 is closer to the light emitting side of the light source 31 than the fourth beam splitter 314; the fourth beam splitter 314 is configured to reflect light of the second waveband and transmit light of the first waveband; the fifth beam splitter 315 is configured to reflect light of the third waveband and transmit light of the first waveband and the second waveband; wherein the wavelength of the second waveband is smaller than the wavelength of the third waveband.

[0164] In the embodiment of the present application, the fourth beam splitter 314 is similar to the second beam splitter 305 described above, and the fifth beam splitter 315 is similar to the first beam splitter 304 described above, and their working principles are the same, which will not be described here. In the embodiment of the present application, the wavelengths corresponding to the first waveband, the second waveband and the third waveband increase in turn; for example, as shown in Figure 14A and Figure 14B , the first waveband is a blue waveband, the second waveband is a green waveband, and the third waveband is a red waveband.

[0165] The structure and function of the near-eye display system are described in detail above, and the structure and function of the image combiner in the near-eye display system will be introduced below taking the near-eye display system shown in Figure 15 as an example.

[0166] Embodiment 1

[0167] In embodiment 1, the structure of the near-eye display system is shown in Figure 15 , the light source 31 is a three-monochromatic laser, the image generator 32 is a spatial light modulator 323, and a mirror 324 is arranged to adjust the light path. The relay optical system 40 is a superlens optical system based on multi-wavelength chromatic aberration correction; and the image combiner is a double-sided super surface. The included angle θ between the image combiner and the human eye observation surface is 10°. The phase distribution of the super surface element 10 in the x direction is shown in Figure 16A , wherein the abscissa represents the position x, and the ordinate represents the corresponding phase at the position x (the range of the ordinate in the figure is 0-7 rad); Figure 16AThe left-middle figure shows the phase distribution with x values ​​ranging from 0 to 10000 μm, and the right-middle figure shows the phase distribution with x values ​​ranging from 0 to 30 μm. Correspondingly, the phase distribution of the phase compensator 21 in this x-direction is shown below. Figure 16B As shown; where the horizontal axis represents position x, and the vertical axis represents the phase corresponding to position x (the range of the vertical axis in the figure is 0 to 7 rad); Figure 16B The left-middle figure shows the phase distribution with x values ​​ranging from 0 to 10000 μm, and the right-middle figure shows the phase distribution with x values ​​ranging from 0 to 30 μm.

[0168] Example 2

[0169] In embodiment 2, the structure of the near-eye display system is as follows: Figure 15 As shown, its light source 31 is a tri-monochrome laser, the image generator 32 is a spatial light modulator 323, and a reflector 324 is provided to adjust the light path. The relay optical system 40 is a superlens optical system based on multi-wavelength chromatic aberration correction; the image combiner is a double-sided metasurface. The difference from the above embodiment 1 is that the angle θ between the image combiner and the human eye observation surface is 20°.

[0170] In the x-direction of the metasurface element 10, the phase distribution of the metasurface element 10 is shown below. Figure 17A As shown; where the horizontal axis represents position x, and the vertical axis represents the phase corresponding to position x (the range of the vertical axis in the figure is 0 to 7 rad); Figure 17A The left-middle figure shows the phase distribution with x values ​​ranging from 0 to 10000 μm, and the right-middle figure shows the phase distribution with x values ​​ranging from 0 to 30 μm. Correspondingly, the phase distribution of the phase compensator 21 in this x-direction is shown below. Figure 17B As shown; where the horizontal axis represents position x, and the vertical axis represents the phase corresponding to position x (the range of the vertical axis in the figure is 0 to 7 rad); Figure 17B The left-middle figure shows the phase distribution with x values ​​ranging from 0 to 10000 μm, and the right-middle figure shows the phase distribution with x values ​​ranging from 0 to 30 μm.

[0171] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An image combiner, characterized by, The application relates to a super surface element (10) and a light control element (20). The super surface element (10) is capable of transmitting at least part of light in a visible light band. The super surface element (10) is configured to modulate imaging light for imaging to a human eye by single reflection, the imaging light being on the same side of the super surface element (10) as the human eye; the super surface element (10) comprises a modulation unit (11) configured to phase modulate the imaging light incident at a first angle and reflect the modulated imaging light at a second angle, wherein the first angle is greater than the second angle so that the incident angle of the modulated imaging light reflected by the super surface element (10) is greater than the reflection angle of the imaging light. The light control element (20) is located on the side of the super surface element (10) away from the imaging light, is configured to transmit at least part of light in the visible light band, and controls at least part of light in the visible light band transmitted through the light control element (20) and the super surface element (10) to be free of aberration. The modulation unit (11) has a plurality of modulation units (11) arranged along an x direction; the modulation unit (11) comprises at least one nanostructure; the x direction is a direction in the plane of the super surface element (10), and the distance between the modulation unit (11) at different positions in the x direction and an observation surface for observing an image of the imaging light is different.

2. The image combiner of claim 1, wherein, The phase modulated by the modulation unit (11) satisfies:

3. The image combiner of claim 2, wherein, The super surface element (10) further comprises a substrate (12); the substrate (12) is transparent in the visible light band; ； wherein denotes the phase modulated by the modulation unit (11) at position x, denotes the second angle, denotes the first angle, k denotes the wave number, denotes a preset constant phase.

4. The image combiner of claim 2, wherein, A plurality of modulation units (11) are arranged on one side of the substrate (12); The light control element (20) is located on the side of the substrate (12) away from the modulation unit (11). The sum of the first angle and the second angle is 90°+ / -Δa; Δa represents an angle less than a preset threshold.

5. The image combiner of claim 2, wherein, The light control element (20) comprises a phase compensator (21); 6. The image combiner of claim 1, wherein, The phase compensator (21) is configured to phase modulate at least part of light in the visible light band, and the phase modulated by the phase compensator (21) can compensate for the phase modulated by the super surface element (10) on at least part of the transmitted visible light. The phase compensator (21) comprises at least one refractive lens with a free-form surface; or 7. The image combiner of claim 6, wherein, The phase compensator (21) is a super lens. In the case that the phase compensator (21) is a super lens, the phase compensator (21) is arranged in close contact with the super surface element (10).

8. The image combiner of claim 7, wherein, The light control element (20) comprises a first polarizer (22); 9. The image combiner of claim 1, wherein, The first polarizer (22) is configured to convert at least part of light in the visible light band transmitted through the first polarizer (22) into light in a first polarization state; ​ The super surface element (10) is configured to reflect the imaging light rays of a second polarization state, and the super surface element (10) performs geometric phase modulation on the incident light rays of the second polarization state; the first polarization state is different from the second polarization state.

10. The image combiner of claim 9, wherein, The first polarization state and the second polarization state are mutually orthogonal.

11. A near-eye display system, comprising: Comprise: An image source (30) and an image combiner as claimed in any one of claims 1-10; The image source (30) is configured to emit imaging light rays capable of being emitted to the image combiner; The image combiner is located on the light emitting side of the image source (30), and the light control element (20) of the image combiner is located on the side of the super surface element (10) of the image combiner away from the image source (30).

12. The near-eye display system of claim 11, wherein, The reflection angle of the super surface element (10) reflecting the imaging light rays is the same as the setting angle of the super surface element (10), and the setting angle of the super surface element (10) is the included angle between the super surface element (10) and the observation surface for observing the image of the imaging light rays.

13. The near-eye display system of claim 12, wherein, The setting angle of the super surface element (10) is less than or equal to 25°.

14. The near-eye display system of claim 11, wherein, Further comprise: A relay optical system (40); The relay optical system (40) is located between the image source (30) and the image combiner, and is configured to adjust the light emitted by the image source (30) to be emitted to the image combiner.

15. The near-eye display system of claim 14, wherein, The relay optical system (40) comprises a light deflection element (41); The light deflection element (41) is configured to reflect the incident imaging light rays to the image combiner.

16. The near-eye display system of claim 11, wherein, In the case where the image combiner is the image combiner as claimed in claim 9 or 10, the image source (30) is configured to emit imaging light rays of a second polarization state.

17. The near-eye display system of claim 16, wherein, The image source (30) comprises a second polarizer (33); The second polarizer (33) is configured to convert the imaging light rays into light rays of the second polarization state before the imaging light rays are emitted to the super surface element (10).

18. The near-eye display system of claim 11, wherein, The image source (30) comprises a light source (31) and an image generator (32); The light source (31) is configured to emit light rays; The image generator (32) is located on the light emitting side of the light source (31) and is configured to convert the light rays emitted by the light source (31) into imaging light rays.

19. The near-eye display system of claim 18, wherein, The light source (31) is configured to emit first light rays of a first waveband, second light rays of a second waveband and third light rays of a third waveband in time division; the first waveband, the second waveband and the third waveband are different wavebands within the visible light waveband, and the super surface element (10) can reflect at least part of the light rays located in the first waveband, the second waveband and the third waveband.

20. The near-eye display system of claim 19, wherein, The light source (31) comprises a first monochromatic light source (301), a second monochromatic light source (302), a third monochromatic light source (303), a first beam splitter (304) and a second beam splitter (305); The first monochromatic light source (301) is used to emit the first light rays, the second monochromatic light source (302) is used to emit the second light rays, and the third monochromatic light source (303) is used to emit the third light rays; The first beam splitter (304) is located on the light emitting side of the first monochromatic light source (301), and is configured to adjust the first light emitted by the first monochromatic light source (301) to have the same light emitting direction as the third light; The second beam splitter (305) is located on the light emitting side of the second monochromatic light source (302), and is configured to adjust the second light emitted by the second monochromatic light source (302) to have the same light emitting direction as the third light.

21. The near-eye display system of claim 20, wherein, The first beam splitter (304) and the second beam splitter (305) are both dichroic mirrors; The first beam splitter (304) and the second beam splitter (305) are both located on the main optical axis of the light source (31), and the first beam splitter (304) is closer to the light emitting side of the light source (31) than the second beam splitter (305); The first beam splitter (304) is configured to reflect the light of the first wave band and transmit the light of the second wave band and the third wave band; The second beam splitter (305) is configured to reflect the light of the second wave band and transmit the light of the third wave band; The wavelengths corresponding to the first wave band, the second wave band and the third wave band increase or decrease in turn.

22. The near-eye display system of claim 20, wherein, The light source (31) further comprises a third beam splitter (306); The third beam splitter (306) is located on the light emitting side of the third monochromatic light source (303), and is configured to adjust the light emitting direction of the third light emitted by the third monochromatic light source (303).

23. The near-eye display system of claim 19, wherein, The light source (31) comprises a fourth monochromatic light source (311), a fifth monochromatic light source (312) and a fluorescent disc (313); The fourth monochromatic light source (311) and the fifth monochromatic light source (312) are both configured to emit the first light; The fluorescent disc (313) is located on the light emitting side of the fourth monochromatic light source (311), and is configured to convert the first light emitted by the fourth monochromatic light source (311) into the second light and the third light, and emit the second light and the third light; the first light emitted by the fifth monochromatic light source (312) is emitted. The wavelength of the first wave band is smaller than the wavelengths of the second wave band and the third wave band.

24. The near-eye display system of claim 23, wherein, The light source (31) further comprises a fourth beam splitter (314) and a fifth beam splitter (315); The fourth beam splitter (314) and the fifth beam splitter (315) are both located on the light emitting side of the fluorescent disc (313); The fourth beam splitter (314) is configured to adjust the second light emitted by the fluorescent disc (313) to have the same light emitting direction as the first light emitted by the fifth monochromatic light source (312); The fifth beam splitter (315) is configured to adjust the third light emitted by the fluorescent disc (313) to have the same light emitting direction as the first light emitted by the fifth monochromatic light source (312).

25. The near-eye display system of claim 24, wherein, The fourth beam splitter (314) and the fifth beam splitter (315) are both dichroic mirrors; The fourth beam splitter (314) and the fifth beam splitter (315) are located on the main optical axis of the light source (31), and the fifth beam splitter (315) is closer to the light emitting side of the light source (31) than the fourth beam splitter (314); The fourth beam splitter (314) is configured to reflect the light of the second wave band and transmit the light of the first wave band; The fifth beam splitter (315) is configured to reflect the light of the third wave band and transmit the light of the first wave band and the second wave band; The wavelength of the second wave band is smaller than the wavelength of the third wave band.

26. The near-eye display system of claim 18, wherein: The image generator (32) comprises a digital micromirror device (321); or The image generator (32) comprises a beam expander (322) and a spatial light modulator (323); the beam expander (322) is located on the light emitting side of the light source (31) and is configured to expand the light emitted by the light source (31); the spatial light modulator (323) is located on the light emitting side of the beam expander (322) and is configured to convert the light emitted by the beam expander (322) into imaging light.

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