CN115185082A

CN115185082A - Image combiner and near-to-eye display system

Info

Publication number: CN115185082A
Application number: CN202210808973.2A
Authority: CN
Inventors: 郝成龙; 谭凤泽; 朱瑞; 朱健
Original assignee: Shenzhen Metalenx Technology Co Ltd
Current assignee: Shenzhen Metalenx Technology Co Ltd
Priority date: 2022-07-11
Filing date: 2022-07-11
Publication date: 2022-10-14

Abstract

The invention provides an image combiner and a near-eye display system, wherein the image combiner comprises: a super surface element and a light management element; the super-surface element is configured to be capable of reflecting the imaging light rays at a smaller reflection angle and to be capable of transmitting at least part of the light rays in the visible light band; the light control element is positioned on a side of the super-surface element away from the imaging light and is configured to be able to transmit at least a portion of light in the visible wavelength band and to control at least a portion of the light in the visible wavelength band transmitted through the light control element and the super-surface element to be aberration-free. According to the image combiner and the near-eye display system provided by the embodiment of the invention, the reflection angle of the imaging light is smaller than the incident angle, so that the thickness of the image combiner can be reduced, the size is smaller, and the light path conversion under the condition of small space size can be realized; the volume weight and the design and processing difficulty of the image combiner are reduced, and the cost can be saved.

Description

Image combiner and near-to-eye display system

Technical Field

The invention relates to the technical field of near-eye display, in particular to an image combiner and a near-eye display system.

Background

The existing MR (Mixed Reality)/AR (Augmented Reality) and the like mainly include an image combiner in the form of a free-form surface and an image combiner in the form of an optical waveguide. However, in any form, the imaging optical path and the external environment optical path enter the human eye at the same time, and the human eye sees a superimposed image of the imaging optical path and the external environment optical path.

Since the image combiner needs to simultaneously process the near-eye display light of the projection optical path and correct the aberration of the ambient light optical path, there are many difficulties in both design and processing. For example: in the aspect of design, the free-form surface is difficult to optimize, and the rainbow effect is difficult to correct by the optical waveguide; in terms of processing, the free-form surface is difficult to process, and the center thickness is difficult to reduce, resulting in discomfort in wearing; the optical waveguide scheme needs to use complex structures such as helical grating and the like, so that the processing difficulty is increased, and the mass production cost is increased.

Partial scheme uses a plurality of small-size wedge-shaped reflecting mirrors to realize the light path conversion of formation of image light, and this although a certain degree can realize the miniaturization, its structure still is more complicated, and the processing degree of difficulty is big, and the volume production is with high costs, is unsuitable to promote in batches.

Disclosure of Invention

To solve the above problems, embodiments of the present invention provide an image combiner and a near-eye display system.

In a first aspect, an embodiment of the present invention provides an image combiner, including: a super surface element and a light management element;

the super-surface element is configured to be capable of reflecting imaging light for imaging and to be capable of transmitting at least part of light in a visible light band; an incident angle of the imaging light rays incident to the super surface element is greater than a reflection angle of the imaging light rays;

the light management element is positioned on a side of the super surface element remote from the imaging light and configured to be able to transmit at least a portion of light in the visible wavelength band and to manage that at least a portion of the light in the visible wavelength band transmitted through the light management element and the super surface element is aberration-free.

In one possible implementation, the super surface element comprises: a plurality of modulation units arranged along the x direction; the modulation unit comprises at least one nanostructure; the x direction is one direction in the plane of the super surface element, and distances between the modulation units at different positions in the x direction and an observation surface for observing images formed by imaging light rays are different;

the modulation unit is configured to perform phase modulation on 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.

In one possible implementation manner, the phase modulated by the modulation unit satisfies the following conditions:

wherein,

representing the phase, theta, modulated by said modulation unit at position x _r Representing said second angle, θ _i Represents the first angle, k represents the wavenumber,

indicating a preset constant phase.

In one possible implementation, the super surface element further includes: a substrate; the substrate is transparent in the visible light band;

the modulation units are arranged on one side of the substrate;

the light ray control element is positioned on one side of the substrate far away from the modulation unit.

In one possible implementation, the sum of the first angle and the second angle is 90 ° ± Δ α; Δ α represents an angle smaller than a preset threshold value.

In one possible implementation, the light control element includes: a phase compensator;

the phase compensator is configured to perform phase modulation on at least part of the light rays in the visible light wave band, and the phase modulated by the phase compensator can compensate the phase modulated by the super surface element on at least part of the transmitted light rays in the visible light wave band.

In one possible implementation, the phase compensator includes a refractive lens having at least one side that is a free-form surface; or,

the phase compensator is a superlens.

In a possible implementation manner, in the case that the phase compensator is a superlens, the phase compensator is disposed in conformity with the supersurface element.

In one possible implementation, the light control element includes: a first polarizer;

the first polarizer is configured to convert at least part of the light in the visible light band transmitted through the first polarizer into light in a first polarization state;

the super-surface element is configured to reflect the imaging light of a second polarization state, and the super-surface element geometrically phase-modulates incident light of the second polarization state; the first polarization state is different from the second polarization state.

In one possible implementation, the first polarization state and the second polarization state are orthogonal to each other.

In a second aspect, an embodiment of the present invention further provides a near-eye display system, including: an image source and an image combiner as described above;

the image source is configured to emit imaging light capable of being directed to the image combiner;

the image combiner is positioned on the light-emitting side of the image source, and the light control element of the image combiner is positioned on the side, far away from the image source, of the super-surface element of the image combiner.

In a possible implementation manner, a reflection angle of the super surface element for reflecting the imaging light is the same as a setting angle of the super surface element, and the setting angle of the super surface element is an included angle between the super surface element and an observation surface for observing an image formed by the imaging light.

In a possible realization, the setting angle of the super surface elements is less than or equal to 25 °.

In one possible implementation, the near-eye display system further includes: a relay optical system;

the relay optical system is positioned between the image source and the image combiner and is configured to adjust the light emitted by the image source to be directed to the image combiner.

In one possible implementation, the relay optical system includes: a light deflecting element;

the light deflecting element is configured to reflect the incoming imaging light to the image combiner.

In one possible implementation, the image source is configured to emit imaging light of a second polarization state.

In one possible implementation, the image source includes a second polarizer;

the second polarizer is configured to convert the imaged light to light of the second polarization state before the imaged light strikes the supersurface element.

In one possible implementation, the image source includes a light source and an image generator;

the light source is configured to emit light;

the image generator is positioned on the light-emitting side of the light source and is configured to convert the light emitted by the light source into imaging light.

In one possible implementation, the light source is configured to emit the first light of the first wavelength band, the second light of the second wavelength band, and the third light of the third wavelength band in a time-sharing manner; the first wave band, the second wave band and the third wave band are different wave bands in a visible light wave band, and the super surface element can reflect at least part of light rays in the first wave band, the second wave band and the third wave band.

In one possible implementation, the light source includes a first monochromatic light source, a second monochromatic light source, a third monochromatic light source, a first beam splitter and a second beam splitter;

the first monochromatic light source is used for emitting the first light, the second monochromatic light source is used for emitting the second light, and the third monochromatic light source is used for emitting the third light;

the first spectroscope is positioned on the light emitting side of the first monochromatic light source and used for adjusting the first light ray emitted by the first monochromatic light source to be in the same emergent direction as the third light ray;

the second spectroscope is positioned on the light-emitting side of the second monochromatic light source and used for adjusting the second light rays emitted by the second monochromatic light source to be the same as the emitting direction of the third light rays.

In a possible implementation manner, the first beam splitter and the second beam splitter are both dichroic mirrors;

the first spectroscope and the second spectroscope are both positioned on a main optical axis of the light source, and the first spectroscope is closer to a light-emitting side of the light source than the second spectroscope;

the first beam splitter is configured to reflect light of the first wavelength band and transmit light of the second and third wavelength bands;

the second beam splitter is configured to reflect light of the second wavelength band and transmit light of the third wavelength band;

the wavelengths corresponding to the first band, the second band and the third band are sequentially increased or decreased.

In one possible implementation, the light source further includes a third beam splitter;

the third beam splitter is located on the light emitting side of the third monochromatic light source and used for adjusting the emitting direction of the third light emitted by the third monochromatic light source.

In one possible implementation, the light source includes a fourth monochromatic light source, a fifth monochromatic light source, and a fluorescent carousel;

the fourth monochromatic light source and the fifth monochromatic light source are both used for emitting the first light;

the fluorescence turntable is positioned on the light-emitting side of the fourth monochromatic light source and used for converting the first light rays emitted by the fourth monochromatic light source into the second light rays and the third light rays and emitting the second light rays and the third light rays; the first light emitted by the fifth monochromatic light source is emitted;

wherein the wavelength of the first band is smaller than the wavelength of the second band and the third band.

In a possible implementation manner, the light source further comprises a fourth spectroscope and a fifth spectroscope;

the fourth spectroscope and the fifth spectroscope are both positioned on the light emitting side of the fluorescence turntable;

the fourth light splitter is used for adjusting the second light converted and emitted by the fluorescent turntable to be the same as the emitting direction of the first light emitted by the fifth monochromatic light source;

and the fifth spectroscope is used for adjusting the third light converted and emitted by the fluorescence turntable to be the same as the emitting direction of the first light emitted by the fifth monochromatic light source.

In one possible implementation manner, the fourth dichroic mirror and the fifth dichroic mirror are both dichroic mirrors;

the fourth spectroscope and the fifth spectroscope are both positioned on a main optical axis of the light source, and the fifth spectroscope is closer to a light emitting side of the light source than the fourth spectroscope;

the fourth beam splitter is configured to reflect light of the second wavelength band and transmit light of the first wavelength band;

the fifth spectroscope is configured to reflect the light of the third wavelength band and transmit the light of the first wavelength band and the light of the second wavelength band;

the wavelength of the second band is less than the wavelength of the third band.

In one possible implementation, the image generator includes: a digital micromirror device; or,

the image generator includes: a beam expander and a spatial light modulator; the beam expander is positioned on the light-emitting side of the light source and is configured to expand the light emitted by the light source; the spatial light modulator is positioned on the light-emitting side of the beam expander and is configured to convert the light emitted by the beam expander into imaging light.

In the solution provided by the first aspect of the embodiments of the present invention, the imaging light can be reflected and at least part of the ambient light in the visible light band can be transmitted, so that the imaging light and the ambient light can enter human eyes together; the super-surface element modulates the incident imaging light to enable the reflection angle of the imaging light to be smaller than the incident angle, and the included angle between the super-surface element and the plane where the human eyes are located is smaller, so that the thickness of the image combiner can be reduced, the size is smaller, and light path conversion under the condition of small space size can be realized; moreover, the super-surface element based on the super-surface technology has the characteristics of being light, thin and easy to process, the volume weight and the design and processing difficulty of the image combiner are reduced, and the cost can be saved. The light control element can be matched with the modulation effect of the super-surface element, so that ambient light still has no modulation after penetrating through the light control element and the super-surface element, and the ambient light can enter human eyes without aberration, so that a user can view an external environment without distortion.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a first structure of an image combiner provided in an embodiment of the invention;

FIG. 2 illustrates a schematic top-view structural view of a super surface element provided by embodiments of the present invention;

FIG. 3 illustrates a side view structural schematic of a super surface element provided by an embodiment of the present invention;

FIG. 4 is a diagram illustrating a second configuration of an image combiner according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a third structure of an image combiner provided in an embodiment of the present invention;

FIG. 6 is a diagram illustrating a fourth structure of an image combiner according to an embodiment of the present invention;

FIG. 7 is a diagram illustrating a fifth structure of an image combiner according to an embodiment of the present invention;

FIG. 8 illustrates a first schematic structural diagram of a near-eye display system provided by an embodiment of the invention;

FIG. 9 is a diagram illustrating a second configuration of a near-eye display system provided by an embodiment of the invention;

FIG. 10 is a schematic diagram illustrating a third configuration of a near-eye display system provided by an embodiment of the invention;

FIG. 11 illustrates a fourth schematic diagram of a near-eye display system provided by an embodiment of the invention;

FIG. 12A illustrates a first structural diagram of an image source provided by an embodiment of the invention;

FIG. 12B is a diagram illustrating a second configuration of an image source according to an embodiment of the invention;

FIG. 13A is a schematic diagram of a third structure of an image source provided by an embodiment of the invention;

FIG. 13B is a diagram illustrating a fourth configuration of an image source according to an embodiment of the invention;

FIG. 14A is a diagram illustrating a fifth configuration of an image source according to an embodiment of the invention;

FIG. 14B is a diagram illustrating a sixth configuration of an image source according to an embodiment of the invention;

FIG. 15 is a detailed schematic diagram of a near-eye display system provided by an embodiment of the invention;

FIG. 16A shows a phase distribution diagram of the super surface element in example 1;

fig. 16B shows a phase profile of the phase compensator in embodiment 1;

FIG. 17A shows the phase distribution profile of the super surface element in example 2;

fig. 17B shows a phase profile of the phase compensator in embodiment 2.

Icon:

10-super surface 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 spectroscope, 305-second spectroscope, 306-third spectroscope, 311-fourth monochromatic light source, 312-fifth monochromatic light source, 313-fluorescent turntable, 314-fourth spectroscope, 315-fifth spectroscope, 321-digital micromirror device, 322-beam expander, 323-spatial light modulator, 324-reflector, 325-transflector prism, 41-light deflection element, 42-refraction lens, 43-super lens, 1-temple.

Detailed Description

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are used merely for convenience of description and simplification of the description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

An embodiment of the present invention provides an image combiner, as shown in fig. 1, including: super surface elements 10 and light management elements 20. The super-surface element 10 is configured to be able to reflect imaging light rays a for imaging and to be able to transmit at least part of light rays B in the visible wavelength band; incident angle theta of imaging light incident on super surface element 10 _i Greater than the angle of reflection theta of the imaging light _r . The light management element 20 is located on the side of the super surface element 10 remote from the imaging light a and is configured to be able to transmit at least part of the light B in the visible wavelength band and to manage that at least part of the light B in the visible wavelength band transmitted through the light management element 20 and the super surface element 10 is aberration free.

The image combiner is capable of providing an image to a human eye and allowing external ambient light to enter the human eye such that the human eye can see the image and the external thing simultaneously. As shown in fig. 1, the imaging light ray a may be imaged in an eye movement range (eyebox), so that a user located in the eye movement range may view an image formed by the imaging light ray a; moreover, external ambient light (e.g., light B in fig. 1) can also be incident on the position of the human eye, so that the user can see the formed image and the external objects within the range of the eye movement at the same time.

In the embodiment of the present invention, the image combiner includes a super surface element 10 designed and manufactured based on a super surface technology, where the super surface element 10 has a transflective function, and is capable of reflecting an imaging light ray a for imaging, so that the imaging light ray a can be reflected to a position where human eyes are located; the super surface element 10 is also capable of transmitting light B, which is light in a visible light wavelength band, for example, a part of light in a visible light wavelength band in ambient light is capable of transmitting the super surface element 10. Since the super lens has a certain transflective effect, the super surface element 10 can be a super lens to realize a transflective function; alternatively, the surface of the super-surface element 10 may be provided with a transflective film, for example, the side of the super-surface element 10 close to the light control element 20 is provided with a transflective film, and the transflective film enhances the transflective effect, which is not limited in this embodiment.

Generally, the super-surface element 10 reflects the imaging light a according to the observation direction of human eyes, and in order to avoid that the human eyes directly observe the device emitting the imaging light a, the difference between the observation direction of the imaging light a entering the super-surface element 10 and the observation direction of the human eyes is large, if the super-surface element 10 realizes the conventional reflection function, the whole thickness of the image combiner is thick; for example, if the imaging light ray a entering the super-surface element 10 is perpendicular to the viewing direction of the human eye (as shown in fig. 1), the super-surface element 10 needs to be at an angle of 45 ° with respect to the viewing direction of the human eye, resulting in a thicker overall image combiner thickness. In the embodiment of the present invention, the super-surface element 10 can reflect light rays with a smaller angle, that is, the light rays incident on the super-surface element 10 have a reflection angle smaller than the incident angle. As shown in FIG. 1, the incident angle of the imaging light A incident on the super surface element 10 is θ _i The super surface element 10 can be arranged at an angle of incidence theta smaller than the angle of incidence theta _i Angle of reflection theta _r The imaging light ray a is reflected.

Since the incident angle of the imaging light entering the super-surface element 10 is larger than the reflection angle, in the case that the included angle between the super-surface element 10 and the plane where the human eye is located (such as the plane where the eyebox is located as shown in fig. 1, the plane is the observation plane for observing the image) is small, the imaging light a entering from the side edge can still be reflected to the position where the human eye is located, so that the imaging can be performed right in front of the human eye. Since the included angle between the super surface element 10 and the plane of the human eye can be smaller, the thickness (thickness in the viewing direction) of the image combiner as a whole is smaller, and the volume of the image combiner can be reduced. Wherein, the included angle between the super surface element 10 and the plane where the human eyes are located is less than 45 degrees; for example, the angle is less than 25 °, and specifically may be 20 °, 10 °, or the like.

In the embodiment of the present invention, the super-surface element 10 with the transflective function also has a certain modulation effect on directly incident ambient light, so that the ambient light transmitted by the super-surface element 10 has aberration, and a user cannot normally view an external environment through the super-surface element 10. Specifically, the light control element 20 is disposed on a side of the super-surface element 10 away from the imaging light a, so that the reflected imaging light a does not reach the light control element 20 and then is reflected to the human eye, and imaging of the imaging light a is not affected; and the ambient light (such as the light ray B shown in fig. 1) entering from the outside can reach the human eye after passing through the light ray control element 20 and the super-surface element 10 in sequence, so that the ambient light entering the human eye is aberration-free under the action of the light ray control element 20.

In the embodiment of the present invention, when the aberration of the ambient light incident on the human eye is sufficiently small, the ambient light is considered to be "aberration-free", and the aberration of the ambient light is not required to be absolutely zero, as long as the user can normally view the external object. For example, if the aberration of the ambient light is less than a predetermined threshold, the ambient light may be considered to be aberration-free.

The image combiner provided by the embodiment of the invention can reflect imaging light and transmit at least part of ambient light of a visible light wave band, so that the imaging light and the ambient light can enter human eyes together; the super-surface element 10 modulates the incident imaging light to enable the reflection angle of the imaging light to be smaller than the incident angle, and the included angle between the super-surface element 10 and the plane where the human eyes are located is smaller, so that the thickness of the image combiner can be reduced, the size is smaller, and light path conversion under the condition of small space size can be realized; moreover, the super-surface element 10 based on the super-surface technology has the characteristics of being light, thin and easy to process, the volume weight and the design and processing difficulty of the image combiner are reduced, and the cost can be saved. The light control element 20 can cooperate with the modulation effect of the super-surface element 10, so that the ambient light is still unmodulated after passing through the light control element 20 and the super-surface element 10, and the ambient light can enter human eyes without aberration, so that a user can view an external environment without distortion.

Alternatively, referring to fig. 2, the super surface element 10 comprises: a plurality of modulation units 11 arranged in the x direction; the x-direction is a direction in the plane of the supersurface element 10, and the distance between the modulation units 11 at different positions in the x-direction and the viewing surface for viewing the image formed by the imaging light is different. The modulation unit 11 is configured to phase-modulate 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.

In the embodiment of the invention, the imaging light ray A incident to the super surface element 10 and the observation position of human eyes are relatively fixed; for example, when the image combiner is applied to AR glasses, the image source emitting the imaging light a is fixed in position, generally on the side of the temple or the lens, and the eye position is also fixed with respect to the AR eye; in this embodiment, the super-surface element 10 is mainly used for reducing the exit angle of the imaging light ray a in a plane where the imaging light ray a and the observation position are located together; specifically, an x direction is set, which is one direction in the plane of the super surface element 10, and is also one direction in the plane in which the imaging light ray a is located in common with the observation position. As shown in fig. 1, the direction corresponding to the super surface element 10 shown in fig. 1 may be an x direction in which distances between the modulation units 11 at different positions in the super surface element 10 and the observation surface are different from each other. For example, if the image combiner is used as a lens of AR glasses, the x-direction may be substantially the direction between the left and right eyes.

The modulation units 11 in the super surface element 10 are arranged along the x direction; as shown in fig. 2, the x direction is the left-right direction, and the plurality of modulation units 11 are arranged and distributed in the left-right direction. The imaging light A is incident to the modulation unit 11 at a first angle, and after being modulated by the modulation unit 11, the imaging light A is incident at a second angleIs reflected; namely, the incident angle of the imaging light ray A is a first angle, and the reflection angle is a second angle; as indicated above, the angle of incidence of the imaging light ray a is greater than the angle of reflection, i.e. the first angle is greater than the second angle. In FIG. 1, [ theta ] is _i I.e. may represent a first angle, theta _r The second angle may be represented. Wherein, the modulation unit 11 may include a nano-structure, forming a super surface element 10 with a similar grating structure; alternatively, as shown in fig. 2, the modulation unit 11 may also include a plurality of nanostructures, and the plurality of nanostructures are arranged in a direction perpendicular to the x direction in the modulation unit 11; the nanostructures are shown as circles in fig. 2.

Optionally, the phase modulated by the modulation unit 11 satisfies:

wherein,

indicating the phase, theta, modulated by the modulation unit 11 at position x _r Denotes a second angle, θ _i Representing a first angle, k representing a wave number,

indicating a preset constant phase.

In the embodiment of the present invention, for the modulation units 11 distributed along the x-direction, since the incident angle is larger than the reflection angle, the two light beams incident in parallel to the super surface element 10 have a phase difference between the reflected light beams thereof

Satisfies the following conditions:

wherein Δ x represents the distance of the two light beams in the x direction; when Δ x approaches 0, we can get:

based on the above formula (3), the above formula (1) can be obtained by integral operation.

The value is any preset value, and may be 0, pi/2, etc., which is not limited in this embodiment. If the modulation unit 11 includes a plurality of nanostructures, the structure of each nanostructure may be the same, and the phase modulated by the nanostructure also satisfies the above formula (1). In the embodiment of the invention, the phase distribution of the super-surface element 10 is arranged along the x direction, so that the reflection angle can be reduced simply, and the design is simple.

Optionally, the sum of the first angle and the second angle is 90 ° ± Δ α; Δ α represents an angle smaller than a preset threshold, i.e. the imaging light ray a incident to the super surface element 10 is substantially perpendicular to the imaging light ray a reflected by the super surface element 10. For example, the preset threshold may be 20 °, specifically, 10 °, 5 °, and the like.

Further alternatively, referring to fig. 1 and 3, the super surface element 10 further comprises: a substrate 12; the substrate 12 is transparent in the visible wavelength band. A plurality of modulation units 11 are arranged on one side of a substrate 12; the light control element 20 is located on a side of the substrate 12 remote from the modulation unit 11.

In the embodiment of the present invention, the super surface element 10 uses the substrate 12 transparent in the visible light band, so that the external ambient light can normally pass through the substrate 12 after passing through the light control element 20. Moreover, in order to avoid the substrate 12 directly reflecting the imaging light a, the modulation unit 11 is located on a side of the substrate 12 close to the imaging light a, and the light control element 20 is located on a side of the substrate 12 far from the modulation unit 11, so that the imaging light a can be reflected after being modulated by the modulation unit 11.

On the basis of any of the above embodiments, the light ray control element 20 can realize that the ambient light enters the human eye without aberration by means of phase compensation or conversion of ambient light characteristics. Specifically, if the super surface element 10 performs phase modulation on the light B when at least part of the light B in the visible light wavelength band passes through the super surface element 10, the light control element 20 may have a phase compensation function; alternatively, if the super-surface element 10 itself has no modulation effect on light with certain characteristics in the visible light band, the light control element 20 may convert the ambient light into light with the characteristics, where the light is a part of the light B in the visible light band, and the light B is not modulated by the super-surface element 10 when passing through the super-surface element 10, so that the human eye can also view the light B without aberration.

Specifically, as shown in fig. 4, the light ray control member 20 includes: a phase compensator 21; the phase compensator 21 is configured to phase modulate at least part of the light rays B in the visible wavelength band, and the phase modulated by the phase compensator 21 is capable of compensating the phase modulated by the super surface element 10 on at least part of the light rays B in the transmitted visible wavelength band.

In the embodiment of the present invention, external ambient light enters the phase compensator 21, at least a portion of the light may pass through the phase compensator 21, and the light passed through the phase compensator 21 may be referred to as light B, i.e., at least a portion of light in the visible light band; and, the phase compensator 21 applies a phase to the light B

I.e. the phase modulated by the phase compensator 21 is

When the light B passes through the super surface element 10, the super surface element 10 applies a phase to the light B

I.e. the phase of the super-surface element 10 modulated by at least part of the light rays B in the transmitted visible wavelength band is

The two phases are complementary to enable the formation of an afocal system such that the light ray B incident on the human eye is aberration-free.

In particular, the phase of the phase compensator 21

Satisfies the following conditions:

where mod () represents the remainder function.

For example, referring to fig. 4, the phase compensator 21 includes a refractive lens having at least one free-form surface, and phase modulation is realized by using the surface of the free-form surface; as shown in fig. 4, the outer side of the refractive lens is a flat surface, and the inner side (the side close to the super surface element 10) is a free-form surface.

Alternatively, referring to fig. 5, the phase compensator 21 is a superlens, and the phase distribution of the superlens can implement a phase compensation function; for example, the phase distribution of the superlens satisfies the above equation (4).

Further alternatively, referring to fig. 6, in the case where the phase compensator 21 is a superlens, the phase compensator 21 is disposed in conformity with the supersurface element 10. For example, the phase compensator 21 and the super-surface element 10 may share the same substrate 12, and the nanostructures of the two are respectively located on two sides of the substrate 12, so that the image combiner is smaller in size and lighter and thinner.

Alternatively, referring to fig. 7, the light control member 20 includes: a first polarizer 22. The first polarizer 22 is configured to convert at least a portion of the light in the visible wavelength band transmitted through the first polarizer 22 into light of a first polarization state; the super-surface element 10 is configured to be able to reflect imaging light of the second polarization state, and the super-surface element 10 geometrically phase-modulates incident light of the second polarization state; the first polarization state is different from the second polarization state.

In the embodiment of the present invention, the super-surface element 10 is a geometric phase super-surface, which can perform phase modulation on the incident light in the second polarization state, but does not perform phase modulation on the light in other polarization states; when the imaging light a in the second polarization state enters the super-surface element 10, it may perform geometric phase modulation on the imaging light a in the second polarization state, and reflect the imaging light a in the second polarization state to human eyes. While the first polarizer 22 is capable of converting ambient light into light of the first polarization state (without introducing aberrations in the process), for example, the first polarizer 22 is only capable of transmitting light of the first polarization state in the visible wavelength band, such that light B transmitted through the first polarizer 22 and reaching the supersurface element 10 is light of the first polarization state. When the light B of the first polarization state passes through the super surface element 10, the super surface element 10 does not perform phase modulation on the light of the first polarization state, so that the ambient light finally reaching the human eye is only the light of the first polarization state, which is still free of aberration.

To ensure imaging, the first polarization state and the second polarization state are orthogonal. For example, the first polarization state is linear polarization with a first polarization direction, and the second polarization state is linear polarization with a second polarization direction, and the first polarization direction is perpendicular to the second polarization direction; or the first polarization state is left-hand circular polarization and the second polarization state is right-hand circular polarization; alternatively, 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 manner of the two polarization states.

An embodiment of the present invention further provides a near-eye display system, as shown in fig. 8, the near-eye display system includes: the image source 30 and the image combiner as provided in any of the above embodiments, i.e. the near-eye display system, comprise a super-surface element 10 and a light control element 20, and fig. 8 illustrates the light control element 20 comprising a phase compensator 21. Wherein the image source 30 is configured to emit imaging light rays that can be directed to an image combiner, such as the imaging light rays a described above; the image combiner is located on the light exit 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 remote from the image source 30.

In the embodiment of the present invention, the image combiner is used to allow the imaging light to enter the super surface element 10 at a larger incident angle, and the volume of the image combiner is smaller. For example, as shown in fig. 8, when the near-to-eye display system is applied to AR glasses, the image source 30 may be located on the temple 1, and the image combiner serves as a lens of the glasses; even if the thickness of the image combiner is small, the imaging light emitted from the image source 30 can still enter the image combiner at a large incident angle and be reflected by the image combiner to the human eye.

Optionally, the super-surface element 10 reflects the image light with a reflection angle θ such that the image light reflected by the image combiner is aligned with the viewing direction of the human eye _r The same setting angle as the super surface element 10; wherein, the setting angle of the super surface element 10 is an included angle between the super surface element 10 and an observation surface for observing an image formed by imaging light; as shown in fig. 8, the setting angle is the angle between the super surface element 10 and the plane in which the eye movement range lies. If the image light incident on the super-surface element 10 is perpendicular to the observation direction of the human eye, the image light incident on the super-surface element 10 is also perpendicular to the image light reflected by the super-surface element 10.

Optionally, the setting angle is the angle between the super surface element 10 and the plane of the human eye. In order to ensure that the thickness of the image combiner is small, the setting angle of the super surface element 10 is less than or equal to 25 °. For example, the setting angle is 20 °, 10 °, or the like.

Further optionally, as shown in fig. 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 light emitted from the image source 30 to be directed to the image combiner.

In the embodiment of the present invention, when the near-eye display system is applied to wearable devices such as AR glasses, since the wearable devices have limited volume, in order to effectively utilize the structural frame of the wearable devices, the relay optical system 40 may be used to adjust the imaging light emitted by the image source 30. For example, as shown in fig. 8, the relay optical system 40 may include a refractive lens 42 and/or a superlens 43 to enable adjustment of the imaging light; alternatively, the relay optical system 40 may include a 4f mirror group, and may realize functions such as image magnification.

Alternatively, as shown in fig. 8, the relay optical system 40 includes: a light deflecting element 41; the light deflecting element 41 is configured to reflect the incoming imaging light to the image combiner. In this embodiment, the light deflecting element 41 is used to reflect the imaging light from the image source 30 at the temple 1 to the image combiner at the lens.

In an embodiment of the present invention, as shown in fig. 8, the light control element 20 may be a phase compensator 21 in the form of a superlens. Moreover, the near-eye display system may also adopt the image combiner shown in fig. 6, and the structure of the near-eye display system can be shown in fig. 9; alternatively, the near-eye display system may also use the image combiner shown in fig. 4, and the structure of the near-eye display system may be as shown in fig. 10.

Alternatively, the near-eye display system may employ the image combiner described above with reference to FIG. 7, i.e., the light control element 20 includes the first polarizer 22, in which case the image source 30 is configured to emit imaging light of the second polarization state. In the embodiment of the present invention, the image source 30 may emit the imaging light in the second polarization state, so that the imaging light a incident on the super surface element 10 is in the second polarization state, and further, the ambient light is incident on the human eye without aberration under the action of the first polarizer 22.

Alternatively, the image source 30 may be a conventional display capable of emitting light of a specific polarization state, such as a liquid crystal display, which emits imaging light of linearly polarized light. Further optionally, as shown in fig. 11, the image source 30 comprises a second polarizer 33; the second polarizer 33 is configured to convert the imaged light to light of a second polarization state before the imaged light impinges on the supersurface element 10. In the embodiment of the present invention, the second polarizer 33 is used to generate the imaging light in the second polarization state, so that the polarization state of the imaging light is relatively good, and the problem of ghost image can be effectively avoided.

On the basis of any of the above embodiments, referring to fig. 8, 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 configured to convert the light emitted from the light source 31 into imaging light.

In the embodiment of the present invention, the light source 31 is a backlight source, which emits light required for imaging by the image generator 32; the image generator 32 can convert the light emitted from the light source 31 into imaging light capable of imaging. For example, the image generator 32 may be a liquid crystal panel and the image source 30 may be a liquid crystal display. In the case that the imaging light in the second polarization state needs to be generated, the second polarizer 33 may be located between the light source 31 and the image generator 32, or may be located on the light emitting side of the image generator 32; as shown in fig. 11, the second polarizer 33 may be embedded in the relay optical system 40, and the position of the second polarizer 33 is not limited in this embodiment.

Optionally, the light source 31 emits light rays with different wave bands in a time sharing manner, and imaging is achieved by using a visual retention effect. Specifically, the light source 31 is configured to emit the first light of the first wavelength band, the second light of the second wavelength band, and the third light of the third wavelength band in a time-sharing manner; the first, second, and third wavelength bands are different wavelength bands within the visible light wavelength band, and the super surface element 10 can reflect at least part of the light within the first, second, and third wavelength bands.

In the embodiment of the present invention, the light source 31 can emit at least three lights in a time-sharing manner, that is, emit the first light, the second light, and the third light in a time-sharing manner, and the duration of each light may be determined by a refresh rate of the near-eye display system, which may be specifically a refresh rate of the image generator 32. For example, for a near-eye display system with a refresh rate of 120Hz, the duration of each beam of light is 8.33 milliseconds; one frame of image can be formed by every three lights (including the first light, the second light and the third light), namely, 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 40Hz.

The super-surface element 10 can modulate at least part of light rays in the first, second and third wave bands, and can reflect the light rays in the three wave bands to human eyes at smaller reflection angles. For example, the super surface element 10 may be a multi-wavelength chromatic aberration correction super surface, which can perform chromatic aberration correction on light in the first wavelength band, the second wavelength band, and the third wavelength band, and can ensure an imaging effect.

Optionally, the image generator 32 comprises: the digital micromirror device 321. Alternatively, 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 configured to expand the light emitted from the light source 31; the spatial light modulator 323 is located on the light-emitting side of the beam expander 322 and configured to convert light emitted from the beam expander 322 into image light.

Wherein, the Digital Micromirror Device (DMD) 321 is an array composed of a plurality of high-speed digital light reflected lights; for example, a DMD is made up of many small aluminum mirror surfaces, the number of mirror plates being determined by the display resolution, one mirror plate for each pixel. The object is imaged on the DMD, and each image point is scanned in sequence through the pixel-level controllable characteristic and the high-speed overturning frequency of the DMD, so that high-speed point scanning imaging can be realized. The Spatial Light Modulator (SLM) 323 may be a liquid crystal spatial light modulator, a spatial light modulator based on a super surface, or the like, which is not limited in this embodiment. Wherein, utilize beam expander 322 to expand the beam to the formation of image light of outgoing to can expand the beam into even and easily formation of image light with laser, make things convenient for spatial light modulator 323 formation of image.

Optionally, the first wavelength band, the second wavelength band, and the third wavelength band are respectively one of a red light wavelength band, a green light wavelength band, and a blue light wavelength band, that is, the projection imaging can be realized by using the light of three primary colors of red, green, and blue; in fig. 12A to 14B described below, red light, green light, and blue light are denoted by R, G, and B, respectively.

Alternatively, as shown in fig. 12A and 12B, 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 for emitting first light rays, the second monochromatic light source 302 is used for emitting second light rays, and the third monochromatic light source 303 is used for emitting 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 be in the same 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 used for adjusting the second light emitted by the second monochromatic light source 302 to be in the same direction as the emitting direction of the third light.

In the embodiment of the present 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, which can operate in a time-sharing manner, so as to emit a first light, a second light, and a third light in a time-sharing manner; after the first light emitted by the first monochromatic light source 301 and the second light emitted by the second monochromatic light source 302 are adjusted by the first beam splitter 304 and the second beam splitter 305, the first light, the second light and the third light can be emitted according to the same emitting direction; as shown in fig. 12A, all three light rays are emitted from bottom to top; alternatively, as shown in FIG. 12B, all three rays exit from left to right. For example, the first light, the second light and the third light are coaxial.

As shown in fig. 12A, the image generator 32 includes a digital micro-mirror device 321, and the light emitted from the light source 31 can be converted into imaging light by controlling the deflection of the mirror at a corresponding position in the digital micro-mirror device 321. As shown in fig. 12A, the image generator 32 may further include a transflective prism 325, which generates imaging light in a desired emergent direction by using a transflective function; as shown in fig. 12A, imaging light rays from left to right may be generated. Alternatively, as shown in fig. 12B, the image generator 32 includes a beam expander 322 and a spatial light modulator 323; light emitted from the light source 31 is expanded by the beam expander 322 and then emitted to the spatial light modulator 323, so that imaging light a capable of imaging is generated.

Optionally, as shown in fig. 13A and 13B, the light source 31 further includes a third beam splitter 306; the third spectroscope 306 is located on the light-emitting side of the third monochromatic light source 303, and is used for adjusting the emitting direction of the third light emitted by the third monochromatic light source 303. In the embodiment of the present invention, the first monochromatic light source 301, the second monochromatic light source 302, and the third monochromatic light source 303 may be arranged in parallel, and the first beam splitter 304, the second beam splitter 305, and the third beam splitter 306 are used to adjust the propagation direction of the light, so that the light can be emitted in the same direction.

Optionally, the first beam splitter 304 and the second beam splitter 305 are both dichroic mirrors. As shown in fig. 12A to 13B, 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 exit side of the light source 31 than the second beam splitter 305. The first beam splitter 304 is configured to reflect light of a first wavelength band and transmit light of a second wavelength band and a third wavelength band; the second beam splitter 305 is configured to reflect light of the second wavelength band and transmit light of the third wavelength band; the wavelengths corresponding to the first, second and third bands are sequentially increased or decreased.

In the embodiment of the present invention, the wavelengths corresponding to the first, second, and third wavelength bands are sequentially increased, for example, the three wavelength bands are a blue light wavelength band, a green light wavelength band, and a red light wavelength band; alternatively, the wavelengths corresponding to the first, second, and third wavelength bands are smaller in order, for example, as shown in fig. 12A to 13B, the three wavelength bands are a red wavelength band, a green wavelength band, and a blue wavelength band in order. According to the arrangement, a proper dichroic mirror can be conveniently selected.

Taking the light source 31 shown in fig. 12A to 13B as an example, the first monochromatic light source 301 is used for emitting red light, the second monochromatic light source 302 is used for emitting green light, and the third monochromatic light source 303 is used for emitting blue light. At this time, the first beam splitter 304 only needs to be capable of reflecting the red band and the light with the wavelength greater than the red band, and transmitting the bands (including the green band and the blue band) with the wavelength less than the red band; similarly, the second beam splitter 305 only needs to be capable of reflecting light in the green wavelength band and having a wavelength longer than that of the green wavelength band and transmitting a wavelength band (including the blue wavelength band) having a wavelength shorter than that of the green wavelength band. The third light splitter 306 may be a dichroic mirror capable of reflecting a blue wavelength band, and may also be a common reflective mirror, which is not limited in this embodiment.

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 central wavelength is smaller than a preset value (for example, 0.1, 0.03, etc.), and the monochromatic light source is considered to be a narrow-band light source.

Alternatively, as shown in fig. 14A and 14B, the light source 31 includes a fourth monochromatic light source 311, a fifth monochromatic light source 312, and a fluorescent turntable 313; the fourth monochromatic light source 311 and the fifth monochromatic light source 312 are both used for emitting the first light; the fluorescent turntable 313 is positioned at the light-emitting side of the fourth monochromatic light source 311 and is used for converting the first light rays emitted by the fourth monochromatic light source 311 into second light rays and third light rays and emitting the second light rays and the third light rays; the first light from the fifth monochromatic light source 312 is emitted. Wherein the wavelength of the first waveband is smaller than the wavelength of the second waveband and the wavelength of the third waveband.

In the embodiment of the invention, the first waveband is a waveband with the minimum wavelength in three wavebands; for example, for RGB light, the first wavelength band is blue wavelength band. The second light and the third light of a larger wavelength band are generated based on the fluorescent turntable 313 by utilizing the characteristic that the fluorescent turntable 313 can excite light of a larger wavelength.

Optionally, as shown in fig. 14A and 14B, the light source 31 further includes a fourth spectroscope 314 and a fifth spectroscope 315. The fourth spectroscope 314 and the fifth spectroscope 315 are both positioned on the light-emitting side of the fluorescence turntable 313; the fourth light splitter 314 is used for adjusting the second light converted and emitted by the fluorescent turntable 313 to be the same as the emitting direction of the first light emitted by the fifth monochromatic light source 312; the fifth spectroscope 315 is used to adjust the third light converted and emitted by the fluorescent turntable 313 to be the same as the emitting direction of the first light emitted by the fifth monochromatic light source 312.

In the embodiment of the present invention, 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 be the same as the emitting direction of the first light emitted by the fifth monochromatic light source 312.

Optionally, the fourth dichroic mirror 314 and the fifth dichroic mirror 315 may also be dichroic mirrors. Like the first beam splitter 304 and the second beam splitter 305 described above, as shown in fig. 14A and 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 exit 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 wavelength band and transmit light of the first wavelength band; the fifth beam splitter 315 is configured to reflect light of the third wavelength band and transmit light of the first and second wavelength bands; wherein the wavelength of the second waveband is less than the wavelength of the third waveband.

In the embodiment of the present invention, the fourth beam splitter 314 is similar to the second beam splitter 305, and the fifth beam splitter 315 is similar to the first beam splitter 304, and their working principles are the same, which are not described herein again. In the embodiment of the invention, the wavelengths corresponding to the first wave band, the second wave band and the third wave band are increased in sequence; for example, as shown in fig. 14A and 14B, the first wavelength band is a blue wavelength band, the second wavelength band is a green wavelength band, and the third wavelength band is a red wavelength band.

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 are described below by taking the near-eye display system shown in fig. 15 as an example.

Example 1

In embodiment 1, the near-eye display system is configured as shown in fig. 15, wherein the light source 31 is a three-monochromatic laser, the image generator 32 is a spatial light modulator 323, and a mirror 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 super-surface. Wherein, the included angle theta between the image combiner and the observation surface of human eyes is 10 degrees. In the x direction of the super surface element 10, the phase distribution of the super surface element 10 is shown in fig. 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 to 7 rad); the left graph in fig. 16A shows the phase distribution in which x takes a value from 0 to 10000 μm, and the right graph shows the phase distribution in which x takes a value from 0 to 30 μm. Accordingly, in the x direction, the phase distribution of the phase compensator 21 is shown in fig. 16B; 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 to 7 rad); in FIG. 16B, the left graph shows the phase distribution where x takes a value from 0 to 10000 μm, and the right graph shows the phase distribution where x takes a value from 0 to 30 μm.

Example 2

In embodiment 2, the near-eye display system is configured as shown in fig. 15, wherein the light source 31 is a three-monochromatic laser, the image generator 32 is a spatial light modulator 323, and a mirror 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 super-surface. The difference from the above-described embodiment 1 is that the angle θ between the image combiner and the viewing surface of the human eye is 20 °.

In the x direction of the super surface element 10, the phase distribution of the super surface element 10 is shown with reference to fig. 17A; 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 to 7 rad); in FIG. 17A, the left graph shows the phase distribution where x takes a value from 0 to 10000 μm, and the right graph shows the phase distribution where x takes a value from 0 to 30 μm. Accordingly, in the x direction, the phase distribution of the phase compensator 21 is shown in fig. 17B; 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 to 7 rad); in FIG. 17B, the left graph shows the phase distribution where x takes a value from 0 to 10000 μm, and the right graph shows the phase distribution where x takes a value from 0 to 30 μm.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the technical scope of the present invention, and the technical scope of the present invention is covered by the modifications or alternatives. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. An image combiner, comprising: -a super surface element (10) and a light control element (20);

the super surface element (10) is configured to be capable of reflecting imaging light for imaging and to be capable of transmitting at least part of light in a visible light band; -the angle of incidence of said imaging light rays incident to said super surface element (10) is larger than the angle of reflection of said imaging light rays;

the light control element (20) is located on a side of the super surface element (10) remote from the imaging light and is configured to be able to pass at least part of the light in the visible wavelength band and to control at least part of the light in the visible wavelength band passing through the light control element (20) and the super surface element (10) to be aberration-free.

2. An image combiner according to claim 1, characterized in that the supersurface element (10) comprises: a plurality of modulation units (11) arranged along the x-direction; the modulation unit (11) comprises at least one nanostructure; the x direction is one direction in the plane of the super surface element (10), and the distances between the modulation units (11) at different positions in the x direction and an observation surface for observing images formed by the imaging light rays are different;

the modulation unit (11) is configured to phase-modulate the imaging light rays incident at a first angle and reflect the modulated imaging light rays at a second angle; the first angle is greater than the second angle.

3. The image combiner according to claim 2, characterized in that the phase modulated by the modulation unit (11) satisfies:

wherein,

represents the phase, theta, modulated by the modulation unit (11) at position x _r Represents the second angle θ _i Represents the first angle, k represents the wavenumber,

indicating a preset constant phase.

4. An image combiner according to claim 2, characterized in that the supersurface element (10) further comprises: a substrate (12); the substrate (12) is transparent in the visible wavelength band;

a plurality of the modulation units (11) are arranged on one side of the substrate (12);

the light control element (20) is located on a side of the substrate (12) remote from the modulation unit (11).

5. The image combiner of claim 2, wherein the sum of the first angle and the second angle is 90 ° ± Δ α; Δ α represents an angle smaller than a preset threshold value.

6. An image combiner according to claim 1, wherein the light control element (20) comprises: a phase compensator (21);

the phase compensator (21) is configured to perform phase modulation on at least part of the light rays in the visible light wave band, and the phase modulated by the phase compensator (21) can compensate the phase modulated by the super surface element (10) on the transmitted at least part of the light rays in the visible light wave band.

7. The image combiner according to claim 6, characterized in that the phase compensator (21) comprises a refractive lens with at least one side being a free-form surface; or,

the phase compensator (21) is a superlens.

8. An image combiner according to claim 7, characterized in that in case the phase compensator (21) is a superlens, the phase compensator (21) is arranged in abutment with the supersurface element (10).

9. An image combiner according to claim 1, wherein the light control element (20) comprises: a first polarizer (22);

the first polarizer (22) is configured to convert at least part of the light in the visible wavelength band transmitted through the first polarizer (22) into light of a first polarization state;

the supersurface element (10) is configured to be able to reflect the imaging light rays of a second polarization state, and the supersurface element (10) geometrically phase modulates 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 orthogonal to each other.

11. A near-eye display system, comprising: an image source (30) and an image combiner according to any of claims 1-10;

the image source (30) is configured to emit imaging light rays that are capable of being directed to the image combiner;

the image combiner is positioned on the light-emitting side of the image source (30), and the light control element (20) of the image combiner is positioned on the side of the super-surface element (10) of the image combiner, which is far away from the image source (30).

12. A near-eye display system as claimed in claim 11 wherein a reflection angle at which the super surface element (10) reflects the imaging light is the same as a setting angle of the super surface element (10), the setting angle of the super surface element (10) being an angle between the super surface element (10) and a viewing surface for viewing an image formed by the imaging light.

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

14. The near-eye display system of claim 11 further comprising: 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 light emitted by the image source (30) to be directed towards the image combiner.

15. A near-eye display system as claimed in claim 14 wherein the relay optical system (40) comprises: a light deflecting element (41);

the light deflecting element (41) is configured to reflect the incoming imaging light to the image combiner.

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

17. A near-eye display system as claimed in claim 16 wherein the image source (30) comprises a second polariser (33);

the second polarizer (33) is configured to convert the imaged light rays to light rays of the second polarization state before the imaged light rays impinge on the supersurface element (10).

18. A near-eye display system as claimed in 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;

the image generator (32) is positioned 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.

19. A near-eye display system as claimed in claim 18 wherein the light source (31) is configured to time-share the first light of the first wavelength band, the second light of the second wavelength band and the third light of the third wavelength band; the first wave band, the second wave band and the third wave band are different wave bands in a visible light wave band, and the super surface element (10) can reflect at least part of light rays in the first wave band, the second wave band and the third wave band.

20. A near-eye display system as claimed in 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);

said first monochromatic light source (301) for emitting said first light, said second monochromatic light source (302) for emitting said second light, said third monochromatic light source (303) for emitting said third light;

the first spectroscope (304) is positioned on the light-emitting side of the first monochromatic light source (301) and is used for adjusting the first light ray emitted by the first monochromatic light source (301) to be in the same emergent 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 for adjusting the second light rays emitted by the second monochromatic light source (302) to be in the same direction as the emitting direction of the third light rays.

21. A near-eye display system according to claim 20 wherein the first beam splitter (304) and the second beam splitter (305) are both dichroic mirrors;

the first spectroscope (304) and the second spectroscope (305) are both located on a main optical axis of the light source (31), and the first spectroscope (304) is closer to a light exit side of the light source (31) than the second spectroscope (305);

the first beam splitter (304) is configured to reflect light of the first wavelength band and transmit light of the second and third wavelength bands;

the second beam splitter (305) is configured to reflect light of the second wavelength band and transmit light of the third wavelength band;

22. A near-eye display system as claimed in 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 used for adjusting the 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 carousel (313);

the fourth monochromatic light source (311) and the fifth monochromatic light source (312) are both used for emitting the first light;

the fluorescent turntable (313) is positioned on the light-emitting side of the fourth monochromatic light source (311) and is used for converting the first light emitted by the fourth monochromatic light source (311) into the second light and the third light and emitting the second light and the third light; the first light emitted by the fifth monochromatic light source (312) is emitted;

24. A near-eye display system as claimed in claim 23 wherein the light source (31) further comprises a fourth beam splitter (314) and a fifth beam splitter (315);

the fourth spectroscope (314) and the fifth spectroscope (315) are both positioned on the light-emitting side of the fluorescence turntable (313);

the fourth light splitter (314) is used for adjusting the second light converted and emitted by the fluorescent turntable (313) to be the same as the emitting direction of the first light emitted by the fifth monochromatic light source (312);

the fifth spectroscope (315) is used for adjusting the third light converted and emitted by the fluorescent turntable (313) to be the same as the emitting direction of the first light emitted by the fifth monochromatic light source (312).

25. A near-eye display system according to claim 24 wherein the fourth dichroic mirror (314) and the fifth dichroic mirror (315) are both dichroic mirrors;

the fourth spectroscope (314) and the fifth spectroscope (315) are both located on a main optical axis of the light source (31), and the fifth spectroscope (315) is closer to a light exit side of the light source (31) than the fourth spectroscope (314);

the fourth beam splitter (314) is configured to reflect light of the second wavelength band and transmit light of the first wavelength band;

the fifth beam splitter (315) is configured to reflect light of the third wavelength band and transmit light of the first wavelength band and the second wavelength band;

26. The near-eye display system of claim 18,

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 positioned 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 positioned 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.