CN217639765U - Holographic near-to-eye display projection system - Google Patents

Abstract

The utility model provides a holographic near-to-eye display projection system, include: the system comprises a projection light source, a spatial light modulator based on a super surface, a projection lens and a light control module; the spatial light modulator comprises a substrate and a plurality of nanostructures made of phase change material; the projection light source is used for emitting projection light rays in a visible light wave band; the spatial light modulator is used for modulating the incident projection light; the projection lens is used for converging projection light; the light control module is used for generating controllable light focuses of a plurality of non-visible light wave bands, and at least part of the nano structures of the spatial light modulator correspond to the light focuses. Through the embodiment of the utility model provides a holographic near-to-eye display projection system can reduce spatial light modulator's cycle to can enlarge spatial light modulator's angle of vision, realize wide-angle projection. And only need add light-operated module can, it is less to projection system's volume influence, be favorable to realizing miniaturization and lightweight.

Description

Holographic near-to-eye display projection system

Technical Field

The utility model relates to a near-to-eye display technology field particularly, relates to a holographic near-to-eye display projection system.

Background

The holographic near-eye display projection method does not cause visual fatigue and dizziness of a user because of no focusing conflict, but a Spatial Light Modulator (SLM) is required for projecting and calculating a holographic image. As the pixel size of the spatial light modulator at the present stage is generally between 3 μm and 12 μm, the maximum total diffraction angle is only 10.5 degrees @550nm, and the requirement of more than 90 degrees of immersive near-eye projection is far less.

In order to solve the problem that the holographic near-eye projection field angle is small, a relay system (4 f system) can be used for reducing the spatial light modulator by M times, so that the field angle is improved; however, the 4f system requires the focal length of the lens, resulting in a thicker overall structure and an increase in system size. Alternatively, the SLM may be illuminated with spherical waves, which may also increase the field angle, but spherical wave illumination requires complex optical components and also greatly increases the size of the system.

SUMMERY OF THE UTILITY MODEL

To solve the above problems, an embodiment of the present invention provides a holographic near-eye display projection system.

The embodiment of the utility model provides a holographic near-to-eye display projection system, include: the device comprises a projection light source, a spatial light modulator based on a super surface, a projection lens and a light control module; the spatial light modulator comprises a substrate and a plurality of nano structures made of phase change materials, wherein the nano structures are periodically arranged on one side of the substrate;

the projection light source is used for emitting projection light rays in a visible light wave band;

the spatial light modulator is positioned on the light emitting side of the projection light source and used for modulating the incident projection light and emitting the modulated projection light;

the projection lens is positioned on the light-emitting side of the spatial light modulator and is used for converging the projection light emitted by the spatial light modulator;

the light control module is used for generating a plurality of controllable light focuses of non-visible light wave bands, the spatial light modulator is positioned on a light focus surface formed by the plurality of light focuses, and at least part of the nano structures correspond to the light focuses; the light control module is not overlapped with the light path of the projection light.

In one possible implementation, the light control module includes: controlling the light source, the wavefront modulator and the optical focusing device;

the control light source is used for emitting control light rays in a non-visible light wave band;

the wavefront modulator is positioned on the light emitting side of the control light source and used for performing wavefront modulation on the incident control light and emitting the wavefront-modulated control light to the optical focusing device;

the optical focusing device is used for focusing the control light after the wave front modulation to form a plurality of optical focuses.

In one possible implementation, the wavefront modulator is located at an entrance pupil location of the optical focusing apparatus.

In a possible implementation manner, the numerical aperture of the optical focusing device is greater than a preset threshold;

under the condition that the numerical aperture of the optical focusing device is the preset threshold value, the size of the optical focus formed on the spatial light modulator by the optical focusing device is not larger than the period of the nano structure.

In one possible implementation, the preset threshold is greater than or equal to 0.6.

In one possible implementation, the wave aberration of the optical focusing device is less than 0.3 λ, λ representing the wavelength of the control light.

In one possible implementation, the optical focusing apparatus includes: a combination lens;

the combined lens is composed of a plurality of lenses; or, consists of at least one lens and at least one superlens; or, alternatively, a plurality of superlenses.

In one possible implementation, the substrate is transparent in the visible band.

In one possible implementation, the spatial light modulator further includes a metal reflective layer;

the metal reflecting layer is positioned between the nano structure and the substrate, and one side of the metal reflecting layer, which is close to the nano structure, is a light reflecting side.

In one possible implementation manner, the light control module is located on a side of the metal reflective layer far away from the nanostructure.

In one possible implementation, the spatial light modulator further comprises a plurality of light-to-heat conversion structures;

the photo-thermal conversion structures are positioned on one side, close to the nano structures, of the substrate, and the photo-thermal conversion structures correspond to the nano structures in position one to one;

the photothermal conversion structure is used for converting the light energy of the light focus into heat energy.

In one possible implementation, the spatial light modulator further includes a dielectric matching layer;

the dielectric matching layer is located between the nanostructures and the substrate and abuts the nanostructures.

In one possible implementation, the spatial light modulator further includes a filling material, and the filling material is transparent in a visible light band;

the filling material is filled between the nano structures, and the difference between the refractive index of the filling material and the refractive index of the nano structures is not less than 0.5.

In one possible implementation, the projection light includes a first light of a first wavelength band, a second light of a second wavelength band, and a third light of a 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;

the projection light source is used for emitting the first light, the second light and the third light in a time-sharing manner.

In one possible implementation, the projection 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 the same as the emergent direction of 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 in the same emergent direction as 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 projection light source, and the first spectroscope is closer to a light-emitting side of the projection 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 projection 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 a possible implementation, the first monochromatic light source, the second monochromatic light source, and the third monochromatic light source are narrow-band lasers or narrow-band light emitting diodes.

In one possible implementation, the projection 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 at the light-emitting side of the fourth monochromatic light source and is 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 projection 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 spectroscope is used for adjusting the second 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;

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, the projection light source further includes a beam expander;

the beam expander is located on the light emitting side of the projection light source and used for expanding the beam of the emergent projection light.

In a possible implementation manner, the first wavelength band, the second wavelength band, and the third wavelength band are each one of a red wavelength band, a green wavelength band, and a blue wavelength band.

In one possible implementation, the non-visible light band is an infrared band.

The embodiment of the utility model provides an in the scheme, the adjustable super surface of making by phase change material utilizes the light-operated module that can form hundred nanometer light focus as spatial light modulator, realizes being the control of the spatial light modulator of hundred nanometers to the pixel element, has reduced spatial light modulator's cycle to can enlarge spatial light modulator's angle of vision, realize wide angle projection. And from the angle of whole size, this scheme only need add light-operated module can, it is less to projection system's volume influence, be favorable to realizing miniaturization and lightweight.

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 these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a holographic near-eye display projection system according to an embodiment of the present invention;

fig. 2 is a schematic diagram of another holographic near-eye display projection system provided by an embodiment of the present invention;

fig. 3A shows a schematic diagram of a first structure of a spatial light modulator provided by an embodiment of the present invention;

fig. 3B is a schematic diagram illustrating a second structure of the spatial light modulator according to the embodiment of the present invention;

fig. 4A shows a third structural diagram of a spatial light modulator provided by an embodiment of the present invention;

fig. 4B shows a fourth structural diagram of a spatial light modulator according to an embodiment of the present invention;

fig. 5A shows a fifth structural diagram of a spatial light modulator according to an embodiment of the present invention;

fig. 5B is a schematic diagram illustrating a sixth structure of a spatial light modulator according to an embodiment of the present invention;

fig. 6A shows a seventh structural diagram of a spatial light modulator according to an embodiment of the present invention;

fig. 6B shows an eighth structural schematic diagram of a spatial light modulator according to an embodiment of the present invention;

fig. 7A shows a ninth structural schematic diagram of a spatial light modulator provided in an embodiment of the present invention;

fig. 7B is a schematic diagram illustrating a tenth structure of a spatial light modulator according to an embodiment of the present invention;

fig. 8A shows an eleventh structural diagram of a spatial light modulator according to an embodiment of the present invention;

fig. 8B is a schematic diagram illustrating a twelfth structure of the spatial light modulator according to an embodiment of the present invention;

fig. 9 is a schematic diagram illustrating a first structure of a projection light source provided by an embodiment of the present invention;

fig. 10 is a schematic diagram illustrating a second structure of a projection light source provided in an embodiment of the present invention;

fig. 11 shows a third structural schematic diagram of a projection light source provided by the embodiment of the present invention.

Icon:

10-projection light source, 20-spatial light modulator, 30-projection lens, 40-light control module, 101-first monochromatic light source, 102-second monochromatic light source, 103-third monochromatic light source, 104-first spectroscope, 105-second spectroscope, 106-third spectroscope, 11-beam expander, 111-fourth monochromatic light source, 112-fifth monochromatic light source, 113-fluorescent turntable, 114-fourth spectroscope, 115-fifth spectroscope, 201-substrate, 202-nanostructure, 203-metal reflecting layer, 204-photothermal conversion structure, 205-medium matching layer, 206-filling material, 401-control light source, 402-wavefront modulator, 403-optical focusing device.

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 only 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 and operated in a particular orientation, and therefore, should not 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 implicitly indicating 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 limited otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, 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 meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

An embodiment of the utility model provides a holographic near-to-eye display projection system, it is shown with fig. 2 to see, include: aprojection light source 10, a spatiallight modulator 20 based on a super surface, aprojection lens 30 and alight control module 40; the spatiallight modulator 20 includes asubstrate 201 and a plurality ofnanostructures 202 made of a phase change material, thenanostructures 202 being periodically arranged on one side of thesubstrate 201.

Theprojection light source 10 is used for emitting projection light in a visible light wave band; the spatiallight modulator 20 is located on the light emitting side of theprojection light source 10, and is configured to modulate the incident projection light and emit the modulated projection light; theprojection lens 30 is located on the light exit side of the spatiallight modulator 20, and is configured to converge the projection light emitted from the spatiallight modulator 20.

Thelight control module 40 is configured to generate a plurality of controllable light focuses in non-visible light bands, the spatiallight modulator 20 is located on a light focus plane formed by the plurality of light focuses, and at least a part of thenanostructures 202 corresponds to the light focus positions; thelight control module 40 does not overlap with the light path of the projection light.

In the embodiment of the present invention, theprojection light source 10 emits projection light for imaging, and after imaging based on the projection light, a user can see a corresponding image; the projection light is light in a visible light wave band so as to be viewed by human eyes; for example, the projection light includes three primary colors of light (red, green, and blue). The spatiallight modulator 20 can load a hologram to be displayed by modulating the projection light, so that the projection light emitted from the spatial light modulator has depth information, frequency spectrum information and the like, and the required image can be generated by the convergence action of theprojection lens 30, and a user can view the formed image with human eyes; figure 1 shows the human eye in a circular pattern on the right. Among them, the implementation of holographic imaging by using a spatial light modulator is a mature technology in the prior art, and will not be described in detail here.

In the embodiment of the present invention, the spatiallight modulator 20 is fabricated based on a super-surface technology, and includes a substrate and a nano-structure located on one side of the substrate; wherein the nanostructure is made based on a phase change material. The phase-change material can change the crystal lattice in the substance under the external excitation of laser and the like, can greatly change the dielectric constant, and changes the state of the phase-change material, thereby realizing phase adjustability. The embodiment of the utility model provides an in, this holographic near-to-eye display projection system can realize the phase control to spatiallight modulator 20 through controlling this light excitation thisnanometer structure 202 through focusing on correspondingnanometer structure 202 department with controllable light. Specifically, the holographic near-eye display projection system utilizes alight control module 40 that can emit a controllable light focus to effect a change in the phase modulation of thenanostructures 202.

The embodiment of the utility model provides an in, light-operatedmodule 40 can form a plurality of light focus, and spatiallight modulator 20 is located the light focal plane department that a plurality of light focus formed, and at leastpartial nanostructure 202 corresponds with the light focus position for the light focus can provide the excitation tonanostructure 202, thereby can change the phase transition state ofnanostructure 202 of phase change material in spatiallight modulator 20, and then changenanostructure 202's modulation effect, thereby can realize the adjustment as required.

Wherein, in order to prevent thelight control module 40 from blocking the projection light, thelight control module 40 is not overlapped with the light path of the projection light. As shown in fig. 1, the spatiallight modulator 20 is transmissive, and thelight control module 40 and the spatiallight modulator 20 may be off-axis, that is, they are not coaxial, so as to effectively avoid blocking the light projected by thelight control module 40. Alternatively, as shown in fig. 2, the spatiallight modulator 20 may also be of a reflective type, and theprojection light source 10 and thelight control module 40 are respectively located at two sides of the spatiallight modulator 20, so that the light paths of the two are not affected by each other; in this case, thelight control module 40 and the spatiallight modulator 20 may be coaxial. Moreover, in order to prevent the light of the optical focus from being projected to human eyes, the light of the optical focus is the light of the invisible light wave band.

The formula of the maximum diffraction angle θ is shown in the following formula (1):

where λ represents the wavelength of the projection light and p is the period on the spatiallight modulator 20. d_eye Represents the distance, d, between theprojection lens 30 and its imaging position_slm Denotes the distance between the spatiallight modulator 20 and theprojection lens 30, d_eye And d_slm The definition of (c) can be seen in fig. 1 and 2.

In the embodiment of the present invention, the spatiallight modulator 20 is a light-operated super-surface, and the size of the pixel unit is very small; since it is feasible to form an optical focus at a hundred nanometer level, the size of the pixel unit of the spatiallight modulator 20 can be designed to be at a hundred nanometer level (e.g., 300 nm), and the optical focus can control the phase change state of the pixel unit in the spatiallight modulator 20, so as to implement phase adjustment and controllability. Moreover, the period p of the conventional spatial light modulator is greatly reduced by the pixel unit of the order of hundreds nanometers, so that the field angle of the spatiallight modulator 20 can be enlarged, and wide-angle projection is realized.

The embodiment of the utility model provides a pair of holographic near-to-eye display projection system, the adjustable surperficial spatial light modulator that is made by phase change material utilizes the light-operatedmodule 40 that can form hundred nanometer light focus, realizes being the control of the spatiallight modulator 20 of hundred nanometer to the pixel element, has reduced spatiallight modulator 20's cycle to can enlarge spatiallight modulator 20's the angle of vision, realize wide-angle projection. And from the angle of whole size, this scheme only need addlight control module 40 can, it is less to projection system's volume influence, be favorable to realizing miniaturization and lightweight.

Alternatively, referring to fig. 1 and 2, thelight control module 40 includes: controlling thelight source 401, thewavefront modulator 402 and the optical focusingdevice 403; the controllight source 401 is used for emitting control light rays in a non-visible light wave band; thewavefront modulator 402 is located on the light emitting side of the controllight source 401, and is configured to perform wavefront modulation on the incident control light and emit the wavefront-modulated control light to the optical focusingdevice 403; the optical focusingdevice 403 is used for focusing the wavefront-modulated control light to form a plurality of optical focuses.

In the embodiment of the present invention, the controllight source 401 emits the control light for generating the light focus; to avoid the control light from being projected to the human eye, the control light is light in the non-visible light band. Optionally, the control light is an infrared light that is safe for the human eye.

The wavefront modulator 402 (also referred to as a wavefront modulator) may change the phase of the light (e.g., via birefringence effects, etc.) to enable changing and controlling the wavefront of the light. As shown in fig. 1, a control light ray a emitted from a controllight source 401 enters awavefront modulator 402, and thewavefront modulator 402 can modulate the wavefront of the control light ray a and send the wavefront-modulated control light ray a to an optical focusingdevice 403. Alternatively, the control light ray a may be a parallel light; as shown in fig. 1, thewavefront modulator 402 can modulate the wavefront of the parallel light into a converging wavefront. Thewavefront modulator 402 may be transmissive (as shown in fig. 1) or reflective, which is not limited in this embodiment. For example, thewavefront modulator 402 may be a Liquid Crystal Spatial Light Modulator (LCSLM), a Digital Micromirror (DMD), or the like.

The optical focusingdevice 403 can focus the wavefront-modulated control light ray a, and can form a plurality of optical focuses. Specifically, the wavefront modulator is located at an entrance pupil position of the optical focusingdevice 403, the optical focusingdevice 403 can generate a plurality of optical focuses with a spacing distance of hundred nanometers, and different optical focuses can correspond todifferent nanostructures 202, so that the control light a can be focused atdifferent nanostructures 202, independent control overdifferent nanostructures 202 is realized, and the spatiallight modulator 20 can realize phase change of hundred-nanometer pixels.

In the embodiment of the present invention, by controlling the modulation effect of thewavefront modulator 402, it is possible to generate a plurality of optical focuses at different positions, for example, a one-to-one correspondence relationship is formed between the generated optical focuses and thenano structures 202 in the spatiallight modulator 20; also, thewavefront modulator 402 can control at whichnanostructures 202 an optical focus is formed, so that light control can be achieved for eachnanostructure 202, and the phase of thenanostructure 202 can be adjusted.

The embodiment of the utility model provides an in, adopt to have crystalline state, amorphous phase changematerial preparation nanostructure 202 to can realize phase modulation under the condition that does not change spatiallight modulator 20 and pass through the reflection characteristic, this spatiallight modulator 20 is the super surface of reflective super surface or transmission type all the time promptly, with the position of conveniently setting upwave front modulator 402,optics focusing device 403, avoid overlapping with projection light B's light path. In the case where the spatiallight modulator 20 is a reflective super-surface, thenanostructure 202 and thewavefront modulator 402 may be disposed on both sides of the reflective spatiallight modulator 20 to be coaxial. For example, the spatiallight modulator 20 includes a metal reflective layer and a plurality of nanostructures, thewavefront modulator 402 and the optical focusingdevice 403 are disposed on one side of the metal reflective layer, the plurality of nanostructures are disposed on the other side of the metal reflective layer, and the other side of the metal reflective layer is a light reflecting side, and the projection light B can be incident into the spatiallight modulator 20 from the other side of the metal reflective layer.

For example, referring to fig. 1, if the spatiallight modulator 20 is a transmissive super surface (e.g., a super lens), the spatiallight modulator 20 can perform phase modulation on the incident projection light B and transmit the modulated projection light; thewavefront modulator 402 and the optical focusingdevice 403 may be disposed on any side of the spatiallight modulator 20, and only need to ensure that there is no overlap with the projection light; in this case, the optical focusingdevice 403 is not coaxial with the spatiallight modulator 20, and the optical focusingdevice 403 needs to be capable of generating an off-axis multi-focus, which is an off-axis multi-focus focusing device. Alternatively, as shown in fig. 2, if the spatiallight modulator 20 is a reflective super-surface, it can reflect the incident projection light B; thewavefront modulator 402 and the optical focusingdevice 403 may be disposed on the other side of the spatiallight modulator 20, thewavefront modulator 402, the optical focusingdevice 403 and the spatiallight modulator 20 may be coaxial, and the optical focusingdevice 403 is an on-axis multi-focus focusing device.

The embodiment of the utility model provides an in, utilizewavefront modulator 402 and optical focusingdevice 403, can generate a plurality of controllable light focus in spatiallight modulator 20 place position, the light focus corresponds with the nano-structure 202 position that phase change material made to can realize independent light-operated to nano-structure 202, change nano-structure 202's phase transition state independently with light-operated mode, thereby can control the pixel level phase transition. The phase change state of the spatiallight modulator 20 is controlled in a light control mode, wiring is not needed, and the limitation of a wiring process is avoided; further, thewavefront modulator 402 and the optical focusingdevice 403 can form an optical focus of hundreds nanometers, and the pixel size of the spatiallight modulator 20 can be reduced, thereby expanding the field angle. For example, the pixel cell size of the spatiallight modulator 20 can be less than or equal to 400nm.

Wherein the phase change material has phase transition states ofThe phase change state specifically includes a crystalline state, an amorphous state, and the like. For example, the phase change material from which thenanostructures 202 are fabricated may be germanium antimony telluride (Ge)_X SB_Y TE_Z ) Germanium telluride (Ge)_X TE_Y ) Antimony telluride (Sb)_X TE_Y ) Silver antimony telluride (Ag)_X SB_Y TE_Z ) And so on. For example, the phase change material is GST (Ge)₂ SB₂ TE₅ ). In general, GST is amorphous; after applying laser excitation to GST, GST is heated, and the amorphous GST is transformed into the crystalline state, so that the rapid conversion of amorphous → crystalline state is realized. Moreover, after the crystalline GST is heated by laser and exceeds the melting point, the crystalline GST can be converted into the amorphous state again through rapid cooling, and the whole cooling process can be rapidly completed within 10ns, so that the rapid conversion of the crystalline state → the amorphous state can be realized. In the embodiment of the utility model provides an in, if withGST preparation nanostructure 202, control light A through the focus can changenanostructure 202's temperature to can realize the crystalline state

Fast switching between amorphous states.

Optionally, the numerical aperture of the optical focusingdevice 403 is larger than a preset threshold. In the case where the numerical aperture of the optical focusingdevice 403 is a preset threshold, the size of the optical focal point formed on the spatiallight modulator 20 by the optical focusingdevice 403 is not greater than the period of thenanostructure 202. For example, the preset threshold is greater than or equal to 0.6. Further optionally, the optical focusingdevice 403 has a wave aberration smaller than 0.3 λ, λ representing the wavelength of the control light a.

In the embodiment of the present invention, the optical focusingdevice 403 is an optical system with large numerical aperture and/or small wave phase difference, so as to generate the optical focus points with hundreds of nanometer intervals. The large numerical aperture and the wavelet aberration ensure that the light focus is smaller and the energy is concentrated, thereby being more beneficial to the precise regulation and control at the pixel level.

Optionally, the optical focusingdevice 403 comprises: a combination lens; the combined lens is composed of a plurality of lenses; or, consists of at least one lens and at least one superlens; or, alternatively, a plurality of superlenses. Wherein the lens is a conventional refractive lens. For example, the optical focusingdevice 403 may be a microscope objective; the micro objective has good aberration correction, meets the system requirements, and can form a required optical focus.

On the basis of any of the above embodiments, thesubstrate 201 of the spatiallight modulator 20 is transparent in the visible light band, so that a transmissive spatiallight modulator 20 can be formed. Wherein, one end of thenano structure 202 close to thesubstrate 201 corresponds to the optical focus position. The structure of the spatiallight modulator 20 can be seen in fig. 3A.

In the embodiment of the present invention, thesubstrate 201 is transparent, and it can at least transmit the projection light B, so as not to affect the image formation of the projection light B. In addition, if thelight control module 40 and the nano-structure 202 are respectively located at two sides of thesubstrate 201, thesubstrate 201 needs to be transparent in a non-visible light band where the control light is located, for example, transparent in an infrared band, so that the control light a can form a light focus at one end of the nano-structure 202 close to thesubstrate 201, and thus the nano-structure 202 is heated by using a photo-thermal conversion effect, and a phase change state of the nano-structure 202 is further changed.

Optionally, referring to fig. 3B, the spatiallight modulator 20 further includes a fillingmaterial 206, and the fillingmaterial 206 is transparent in the operating band; the fillingmaterial 206 is filled between the nano-structures 202, and a difference between a refractive index of the fillingmaterial 206 and a refractive index of the nano-structures 202 is not less than 0.5. In the embodiment of the present invention, the fillingmaterial 206 filled around the nano-structure 202 can function as a filler including the nano-structure 202, and the difference between the refractive index of the fillingmaterial 206 and the refractive index of the nano-structure 202 is greater than or equal to 0.5, so as to prevent the fillingmaterial 206 from affecting the light modulation effect. The working wavelength band refers to a wavelength band where the projection light B is located, that is, a visible light wavelength band, and the fillingmaterial 206 is at least capable of transmitting the projection light B.

Alternatively, referring to fig. 4A, the spatiallight modulator 20 further includes a plurality ofphotothermal conversion structures 204; the photo-thermal conversion structures 204 are positioned on one side of thesubstrate 201 close to the nano-structures 202, and the positions of the photo-thermal conversion structures 204 and the nano-structures 202 are in one-to-one correspondence; thephotothermal conversion structure 204 is used to convert the light energy of the light focus into thermal energy.

The embodiment of the utility model provides an in, set up the light andheat conversion structure 204 that the position corresponds in one side ofnanostructure 202 for light focus can focus on this light andheat conversion structure 204 department, and this light andheat conversion structure 204 can be fast with light energy conversion heat energy, thereby can improve phase transition speed and efficiency. For example, thephotothermal conversion structure 204 may be made of a photothermographic material.

In addition, optionally, similar to the structure shown in fig. 3B, the spatiallight modulator 20 may also include a fillingmaterial 206, which is specifically shown in fig. 4B, and the fillingmaterial 206 has the same function as the fillingmaterial 206 in the embodiment shown in fig. 3B, and is not described herein again.

Optionally, referring to fig. 5A, the spatiallight modulator 20 further comprises adielectric matching layer 205; thedielectric matching layer 205 is located between thenanostructures 202 and thesubstrate 201 and abuts thenanostructures 202.

In the embodiment of the present invention, the difference between the refractive index of themedium matching layer 205 and the refractive index of the nanostructure 202 (or the equivalent refractive index of the nanostructure 202) is less than or equal to the predetermined threshold, for example, the predetermined threshold is 1 or 0.5, etc., so that the refractive index of thenanostructure 202 matches the refractive index of themedium matching layer 205, thereby improving the transmittance of thenanostructure 202. For example, thedielectric matching layer 205 may have a thickness of 30nm to 1000nm. Thedielectric matching layer 205 is transparent in the operating wavelength band, and can transmit the projection light B, for example. For example, the material of thedielectric matching layer 205 may be quartz glass. Further alternatively, the spatiallight modulator 20 may also include a fillingmaterial 206, similar to the structure shown in fig. 3B, as described above, and particularly shown in fig. 5B.

Alternatively, referring to fig. 6A, the spatiallight modulator 20 further includes a metalreflective layer 203; the metalreflective layer 203 is located between thenanostructure 202 and thesubstrate 201, and a side of the metalreflective layer 203 close to thenanostructure 202 is a light-reflecting side.

In the embodiment of the present invention, the spatiallight modulator 20 may be a reflective super-surface, which includes a metalreflective layer 203, and thenano structure 202 is located on the reflective side of the metalreflective layer 203, so that the spatiallight modulator 20 can perform phase modulation in a manner of reflecting incident light. For example, the metalreflective layer 203 may be made of gold, silver, copper, aluminum or an alloy thereof, and the thickness thereof may be 100nm to 100 μm, and optionally, the spatiallight modulator 20 may also include a fillingmaterial 206, as shown in fig. 6B.

For example, in the case that the spatiallight modulator 20 is a reflective super-surface, thenanostructure 202 and the light control module 40 (e.g., the controllight source 401, thewavefront modulator 402, the optical focusingdevice 403, etc.) may be located on two sides of the metalreflective layer 203, that is, thelight control module 40 is located on one side of the metalreflective layer 203 far from thenanostructure 202, so that thelight control module 40 and the spatiallight modulator 20 may be coaxial to conveniently form a light focus.

Alternatively, referring to fig. 7A, the spatiallight modulator 20 further includes a plurality ofphotothermal conversion structures 204; the plurality ofphotothermal conversion structures 204 are located on one side of thesubstrate 201 close to the nano-structures 202, and thephotothermal conversion structures 204 correspond to the nano-structures 202 in position one by one; thephotothermal conversion structure 204 is used to convert the light energy of the light focus into heat energy.

The embodiment of the utility model provides an in, set up the light andheat conversion structure 204 that the position corresponds in one side ofnanostructure 202 for light focus can focus on this light andheat conversion structure 204 department, and this light andheat conversion structure 204 can be fast with light energy conversion heat energy, thereby can improve phase transition speed and efficiency. For example, thephotothermal conversion structure 204 is disposed between thesubstrate 201 and the metalreflective layer 203, so that the tunable super-surface system is a coaxial system, and the control light ray a can be simply and conveniently emitted to thephotothermal conversion structure 204 and forms a light focus. Further optionally, the spatiallight modulator 20 may also comprise a fillingmaterial 206, as shown in particular in fig. 7B.

Optionally, referring to fig. 8A, the spatiallight modulator 20 further comprises adielectric matching layer 205; thedielectric matching layer 205 is positioned between thenanostructures 202 and thesubstrate 201 and abuts thenanostructures 202. As shown in fig. 8A, thedielectric matching layer 205 may be located between thenanostructures 202 and the metalreflective layer 203.

In the embodiment of the present invention, the difference between the refractive index of themedium matching layer 205 and the refractive index of the nanostructure 202 (or the equivalent refractive index of the nanostructure 202) is less than or equal to the predetermined threshold, for example, the predetermined threshold is 1 or 0.5, etc., so that the refractive index of thenanostructure 202 matches the refractive index of themedium matching layer 205, thereby improving the transmittance of thenanostructure 202. For example, thedielectric matching layer 205 may have a thickness of 30nm to 1000nm. Thedielectric matching layer 205 is transparent in the operating wavelength band, and can transmit the projection light B, for example. For example, the material of thedielectric matching layer 205 may be quartz glass. Further optionally, the spatiallight modulator 20 may also comprise a fillingmaterial 206, as shown in particular in fig. 8B.

In addition, optionally, theprojection light source 10 emits light of different wavelength bands in a time sharing manner, and imaging is realized by using a visual retention effect. Specifically, the projection light emitted by theprojection light source 10 includes a first light of a first wavelength band, a second light of a second wavelength band, and a third light of a 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. Theprojection light source 10 is used for emitting a first light, a second light and a third light in a time-sharing manner.

In the embodiment of the present invention, theprojection light source 10 can emit at least three lights at different times, that is, emit the first light, the second light and the third light at different times, and the duration of each light can be determined by the refresh rate of the transparent system. For example, for a projection system with a refresh rate of 120Hz, each beam of light has a duration of 2.78 milliseconds. As another example, for a 60Hz projection system, the duration of each beam of light does not exceed 5.56 milliseconds.

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; fig. 9 to 11 show red, green and blue light as R, G and B, respectively.

Alternatively, referring to fig. 9, theprojection light source 10 includes a first monochromaticlight source 101, a second monochromaticlight source 102, a third monochromaticlight source 103, afirst beam splitter 104, and asecond beam splitter 105; the first monochromaticlight source 101 is used for emitting first light, the second monochromaticlight source 102 is used for emitting second light, and the third monochromaticlight source 103 is used for emitting third light.

Thefirst spectroscope 104 is located on the light-emitting side of the first monochromaticlight source 101 and is used for adjusting the first light ray emitted by the first monochromaticlight source 101 to be in the same emergent direction as the third light ray; in fig. 9, the exit direction of the third light ray is from left to right. Thesecond beam splitter 105 is located on the light emitting side of the second monochromaticlight source 102, and is configured to adjust the second light emitted by the second monochromaticlight source 102 to be in the same emitting direction as the third light.

In the embodiment of the present invention, theprojection light source 10 includes a first monochromaticlight source 101, a second monochromaticlight source 102 and a third monochromaticlight source 103, which can work 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 monochromaticlight source 101 and the second light emitted by the second monochromaticlight source 102 are adjusted by thefirst beam splitter 104 and thesecond beam splitter 105, the first light, the second light and the third light can be emitted according to the same emitting direction, as shown in fig. 9, the three lights are emitted from left to right, and a projection light B is formed. For example, the first light, the second light and the third light are coaxial.

Optionally, as shown in fig. 10, theprojection light source 10 further includes athird beam splitter 106; thethird beam splitter 106 is located on the light emitting side of the third monochromaticlight source 103, and is configured to adjust the emitting direction of the third light emitted by the third monochromaticlight source 103. The embodiment of the utility model provides an in, firstmonochromatic source 101, secondmonochromatic source 102, thirdmonochromatic source 103 can set up side by side, utilize the propagation direction offirst spectroscope 104,second spectroscope 105,third spectroscope 106 adjustment light for the three can jet out with the ground.

Optionally, thefirst beam splitter 104 and thesecond beam splitter 105 are both dichroic mirrors. As shown in fig. 9 and 10, thefirst beam splitter 104 and thesecond beam splitter 105 are both located on the main optical axis of theprojection light source 10, and thefirst beam splitter 104 is closer to the light exit side of theprojection light source 10 than thesecond beam splitter 105. Thefirst beam splitter 104 is configured to reflect light of a first wavelength band and transmit light of a second wavelength band and a third wavelength band; thesecond beam splitter 105 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 sequentially 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 sequence, for example, as shown in fig. 9 and 10, the three wavelength bands are a red wavelength band, a green wavelength band, and a blue wavelength band in sequence. According to the arrangement, a proper dichroic mirror can be conveniently selected.

Taking fig. 9 and 10 as an example, the first monochromaticlight source 101 is used for emitting red light, the second monochromaticlight source 102 is used for emitting green light, and the third monochromaticlight source 103 is used for emitting blue light. At this time, thefirst beam splitter 104 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, thesecond beam splitter 105 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 light in a wavelength band (including the blue wavelength band) shorter than that of the green wavelength band. The thirdlight splitter 106 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 monochromaticlight source 101, the second monochromaticlight source 102, and the third monochromaticlight source 103 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.

Further alternatively, referring to fig. 11, theprojection light source 10 includes a fourth monochromaticlight source 111, a fifth monochromaticlight source 112, and afluorescent turntable 113. The fourth monochromaticlight source 111 and the fifth monochromaticlight source 112 are both used for emitting first light; thefluorescent turntable 113 is positioned at the light-emitting side of the fourth monochromaticlight source 111 and is used for converting the first light emitted by the fourth monochromaticlight source 111 into second light and third light and emitting the second light and the third light; the first light from the fifth monochromaticlight source 112 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 present invention, the first wavelength band is the wavelength band with the smallest wavelength among the three wavelength bands; for example, for RGB light, the first wavelength band is a blue wavelength band. By utilizing the characteristic that thefluorescent turntable 113 can excite light rays with larger wavelengths, the second light rays and the third light rays with larger wave bands are generated based on thefluorescent turntable 113.

Optionally, as shown in fig. 11, theprojection light source 10 further includes afourth spectroscope 114 and afifth spectroscope 115; thefourth spectroscope 114 and thefifth spectroscope 115 are both located on the light exit side of thefluorescent rotary disk 113.

Thefourth spectroscope 114 is used for adjusting the second light converted and emitted by thefluorescent turntable 113 to be the same as the emitting direction of the first light emitted by the fifth monochromaticlight source 112; thefifth spectroscope 115 is used to adjust the third light converted and emitted by thefluorescent turntable 113 to the same direction as the first light emitted by the fifth monochromaticlight source 112.

In the embodiment of the present invention, thefourth spectroscope 114 and thefifth spectroscope 115 are similar to thefirst spectroscope 104 and thesecond spectroscope 105 in the above embodiments, and the second light and the third light after conversion can be adjusted to be the same as the emitting direction of the first light emitted by the fifth monochromaticlight source 112. Optionally, thefourth spectroscope 114 and thefifth spectroscope 115 may also be dichroic mirrors, and the working principle thereof is the same as that of thefirst spectroscope 104 and thesecond spectroscope 105, which is not described herein again.

Further optionally, as shown in fig. 9 to 11, theprojection light source 10 further includes abeam expander 11; thebeam expander 11 is located the light-emitting side of theprojection light source 10 and is used for expanding the beam of the emergent projection light, so that the laser beam can be expanded to the uniform and easy-to-image projection light B.

The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the technical solutions of the changes or replacements within the technical scope of the present invention, and all should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (23)

1. A holographic near-eye display projection system, comprising: the system comprises a projection light source (10), a spatial light modulator (20) based on a super surface, a projection lens (30) and a light control module (40); the spatial light modulator (20) comprises a substrate (201) and a plurality of nano-structures (202) made of phase change material, wherein the nano-structures (202) are periodically arranged on one side of the substrate (201);

the projection light source (10) is used for emitting projection light rays in a visible light wave band;

the spatial light modulator (20) is positioned on the light emergent side of the projection light source (10) and is used for modulating the incident projection light and emitting the modulated projection light;

the projection lens (30) is positioned on the light-emitting side of the spatial light modulator (20) and is used for converging the projection light emitted by the spatial light modulator (20);

the light control module (40) is used for generating a plurality of controllable light focuses in non-visible light bands, the spatial light modulator (20) is positioned on a light focus surface formed by the plurality of light focuses, and at least part of the nano structures (202) correspond to the light focus positions; the light control module (40) is not overlapped with the light path of the projection light.

2. The system according to claim 1, characterized in that said light control module (40) comprises: controlling a light source (401), a wavefront modulator (402) and an optical focusing device (403);

the control light source (401) is used for emitting control light rays in a non-visible light wave band;

the wavefront modulator (402) is located on the light emitting side of the control light source (401), and is used for performing wavefront modulation on the incident control light and emitting the wavefront-modulated control light to the optical focusing device (403);

the optical focusing device (403) is used for focusing the control light after the wave front modulation to form a plurality of optical focuses.

3. The system according to claim 2, characterized in that the wavefront modulator (402) is located at the entrance pupil position of the optical focusing device (403).

4. The system according to claim 2, characterized in that the numerical aperture of the optical focusing device (403) is greater than a preset threshold;

in the case that the numerical aperture of the optical focusing device (403) is the preset threshold, the size of the optical focal point formed on the spatial light modulator (20) by the optical focusing device (403) is not larger than the period of the nanostructure (202).

5. The system of claim 4, wherein the preset threshold is greater than or equal to 0.6.

6. A system according to claim 2, wherein the wave aberration of the optical focusing means (403) is less than 0.3 λ, λ being the wavelength of the control light.

7. The system according to claim 2, wherein the optical focusing device (403) comprises: a combination lens;

the combined lens is composed of a plurality of lenses; or, consists of at least one lens and at least one superlens; or, alternatively, a plurality of superlenses.

8. The system of claim 1, wherein the substrate (201) is transparent in the visible wavelength band.

9. The system of claim 1, wherein the spatial light modulator (20) further comprises a metallic reflective layer (203);

the metal reflecting layer (203) is located between the nano structure (202) and the substrate (201), and one side, close to the nano structure (202), of the metal reflecting layer (203) is a light reflecting side.

10. The system according to claim 9, wherein the light control module (40) is located on a side of the metallic reflective layer (203) remote from the nanostructures (202).

11. The system according to any of claims 8-10, wherein the spatial light modulator (20) further comprises a plurality of light-to-heat converting structures (204);

a plurality of photo-thermal conversion structures (204) are positioned on one side of the substrate (201) close to the nano-structures (202), and the photo-thermal conversion structures (204) correspond to the nano-structures (202) in position one by one;

the photothermal conversion structure (204) is for converting the light energy of the light focus into thermal energy.

12. The system according to any of claims 8-10, wherein said spatial light modulator (20) further comprises a dielectric matching layer (205);

the dielectric matching layer (205) is located between the nanostructures (202) and the substrate (201) and abuts the nanostructures (202).

13. The system according to any of claims 8-10, wherein the spatial light modulator (20) further comprises a fill material (206), the fill material (206) being transparent in the visible wavelength band;

the filling material (206) is filled between the nano structures (202), and the difference between the refractive index of the filling material (206) and the refractive index of the nano structures (202) is not less than 0.5.

14. The system of claim 1, wherein the projected light includes a first light of a first wavelength band, a second light of a second wavelength band, and a third light of a 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;

the projection light source (10) is used for emitting the first light ray, the second light ray and the third light ray in a time-sharing mode.

15. The system according to claim 14, wherein the projection light source (10) comprises a first monochromatic light source (101), a second monochromatic light source (102), a third monochromatic light source (103), a first beam splitter (104) and a second beam splitter (105);

the first monochromatic light source (101) is used for emitting the first light, the second monochromatic light source (102) is used for emitting the second light, and the third monochromatic light source (103) is used for emitting the third light;

the first spectroscope (104) is positioned on the light-emitting side of the first monochromatic light source (101) and is used for adjusting the first light ray emitted by the first monochromatic light source (101) to be in the same emergent direction as the third light ray;

the second beam splitter (105) is located on the light emitting side of the second monochromatic light source (102) and is used for adjusting the second light rays emitted by the second monochromatic light source (102) to be in the same emitting direction as the third light rays.

16. The system according to claim 15, wherein the first beam splitter (104) and the second beam splitter (105) are each dichroic mirrors;

the first spectroscope (104) and the second spectroscope (105) are both positioned on a main optical axis of the projection light source (10), and the first spectroscope (104) is closer to a light outlet side of the projection light source (10) than the second spectroscope (105);

the first beam splitter (104) is configured to reflect light of the first wavelength band and transmit light of the second and third wavelength bands;

the second beam splitter (105) 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.

17. The system of claim 15, wherein the projection light source (10) further comprises a third beam splitter (106);

the third beam splitter (106) is located on the light emitting side of the third monochromatic light source (103) and is used for adjusting the emitting direction of the third light emitted by the third monochromatic light source (103).

18. The system according to claim 15, wherein the first monochromatic light source (101), the second monochromatic light source (102), the third monochromatic light source (103) are narrow-band lasers or narrow-band light emitting diodes.

19. The system according to claim 14, wherein the projection light source (10) comprises a fourth monochromatic light source (111), a fifth monochromatic light source (112), and a fluorescent carousel (113);

the fourth monochromatic light source (111) and the fifth monochromatic light source (112) are both used for emitting the first light;

the fluorescence turntable (113) is positioned on the light-emitting side of the fourth monochromatic light source (111) and is used for converting the first light emitted by the fourth monochromatic light source (111) into the second light and the third light and emitting the second light and the third light; the first light ray emitted by the fifth monochromatic light source (112) is emitted;

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

20. The system of claim 19, wherein the projection light source (10) further comprises a fourth beam splitter (114) and a fifth beam splitter (115);

the fourth spectroscope (114) and the fifth spectroscope (115) are both positioned on the light-emitting side of the fluorescence turntable (113);

the fourth light splitter (114) is used for adjusting the second light converted and emitted by the fluorescent turntable (113) to be the same as the emitting direction of the first light emitted by the fifth monochromatic light source (112);

the fifth spectroscope (115) is used for adjusting the third light converted and emitted by the fluorescent turntable (113) to be the same as the emitting direction of the first light emitted by the fifth monochromatic light source (112).

21. The system according to any one of claims 14-20, wherein the projection light source (10) further comprises a beam expander (11);

the beam expander (11) is located on the light emitting side of the projection light source (10) and used for expanding the emitted projection light.

22. The system according to any one of claims 14-20, wherein the first, second, and third wavelength bands are each one of a red, green, and blue wavelength band.

23. The system of claim 1, wherein the non-visible light band is an infrared band.

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