A light field display system and method based on metasurfaces

Abstract

This invention provides a metasurface-based light field display system and method. The metasurface-based light field display system includes: a light source device for emitting outgoing light rays, the intensity of which is calculated by a computer using ray tracing based on a three-dimensional light field model to be displayed; wherein the intensity of the outgoing light rays carries RGB information of different intensities; a metasurface device for freely stereoscopically modulating the light field of the outgoing light rays to reconstruct the three-dimensional light field model to be displayed, resulting in a naked-eye visible three-dimensional light field model; the metasurface device is fabricated based on superatoms and phase templates through electron beam exposure and reactive ion etching; wherein the light source device and the metasurface device are arranged sequentially in the optical path of the outgoing light rays; the outgoing light rays are collimated rays. This invention has the advantages of small size, light weight, and stable structure, achieving naked-eye three-dimensional display with less limitation on viewing angle and controllable display effect.

Description

Technical Field

[0001] This invention relates to the field of computer image display technology, and in particular to a light field display system and method based on metasurfaces. Background Technology

[0002] 3D display is a technology that can display scenes and objects with a sense of depth, allowing observers to directly observe three-dimensional images with physical depth. Currently, 3D display technologies mainly include glasses-free and device-assisted displays. Among them, glasses-free 3D display technology has attracted much attention due to its advantages of not requiring glasses or other auxiliary devices and its convenience and flexibility.

[0003] Naked-eye 3D display technology, also known as free-form stereoscopic display technology, is a type of light field display technology. It projects encoded light field information into different directions in space using light field modulation devices, forming a true 3D light field with continuous parallax in different directions, simultaneously providing stereoscopic parallax in multiple directions, including horizontal and vertical. Traditional naked-eye 3D display devices are mostly based on lens arrays and other similar components. Limited by lens manufacturing processes and refraction modulation models, their 3D viewing angle, 3D resolution, and display depth are constrained, resulting in poor 3D display effects. Summary of the Invention

[0004] This invention provides a light field display system and method based on metasurfaces to solve the shortcomings of existing technologies that are limited by the focal length and refraction angle of lenses and other devices, which prevent the simultaneous improvement of the resolution, depth and viewing angle performance of three-dimensional images. This invention achieves the effect of naked-eye three-dimensional display with less restriction on viewing angle and controllable display effect.

[0005] This invention provides a light field display system based on metasurfaces, comprising:

[0006] A light source device is used to emit outgoing light rays, the intensity of which is calculated by a computer based on a three-dimensional light field model to be displayed through ray tracing; wherein the intensity of the outgoing light rays carries RGB information of different intensities.

[0007] A metasurface device is used to modulate the light field of the emitted light in a free-form three-dimensional display to reconstruct the three-dimensional light field model to be displayed, thereby obtaining the three-dimensional light field model to be displayed that is visible to the naked eye; the metasurface device is prepared based on superatoms and phase templates through electron beam exposure and reactive ion etching;

[0008] The light source device and the metasurface device are arranged sequentially in the optical path of the emitted light; the emitted light is a collimated light.

[0009] According to the present invention, a light field display system based on a metasurface is provided, wherein the light source device includes a preset number of light source sub-pixels, and the metasurface device includes a preset number of independent metasurface modulation regions; wherein each light source sub-pixel of the light source device corresponds to an independent metasurface modulation region of the metasurface device.

[0010] According to the present invention, a light field display system based on a metasurface is provided. The metasurface device is prepared by electron beam exposure and reactive ion etching based on superatoms and a phase template, specifically including the following steps:

[0011] S1: Calculate the target angle range of the emitted light rays from the free stereoscopic light field based on the target viewing point area of ​​the stereoscopic holographic light field in space; the target angle range is denoted as the emitted light field.

[0012] S2: The metasurface device is converted into a phase template and simulated to obtain a target phase template, which can modulate the incident light field of the light source device into an outgoing light field.

[0013] S3: Based on a pre-built superatomic database, the superatomic size is used as the pixel size, and the elements are arranged according to the target phase template to obtain the metasurface required for a single sub-pixel;

[0014] Repeat steps S1-S3 for all the subpixels to obtain the metasurface structure of the entire display area;

[0015] Metasurface devices are prepared by combining electron beam lithography or photolithography with reactive ion etching.

[0016] According to the present invention, a light field display system based on metasurface is provided, wherein the metasurface device is fabricated using silicon nitride or silicon dioxide.

[0017] According to the present invention, a light field display system based on metasurface is provided, wherein the light source device adopts collimated backlight illuminating a three-color filter or collimated LED self-illumination.

[0018] The present invention also provides a light field display method based on metasurfaces, comprising:

[0019] Obtain the 3D light field model to be displayed;

[0020] Based on the three-dimensional light field model to be displayed, the emitted light rays with different intensities carrying RGB information are obtained by ray tracing calculation using a computer.

[0021] The emitted light rays are subjected to free stereoscopic display light field modulation to restore the three-dimensional light field model to be displayed, thereby obtaining the three-dimensional light field model to be displayed that is visible to the naked eye;

[0022] The emitted light ray is a collimated light ray.

[0023] According to the present invention, a light field display method based on metasurfaces is provided, wherein the ray tracing calculation includes:

[0024] The angle of the light rays after refraction through the metasurface is calculated based on the preset structure of the metasurface device. The emitted light rays are then encoded in RGB and light intensity according to the angle of the light rays in space and the three-dimensional light field model to be displayed.

[0025] According to the present invention, a light field display method based on a metasurface modulates the emitted light rays for free stereoscopic display, specifically including:

[0026] Based on the preset structure of the metasurface device, the emitted light is refracted in a directional manner to modulate the intensity and direction of the light field, thereby generating a free three-dimensional light field in different directions in space.

[0027] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the light field display method based on metasurface as described above.

[0028] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the metasurface-based light field display method as described above.

[0029] This invention provides a metasurface-based light field display system and method. The metasurface-based light field display system includes: a light source device for emitting outgoing light rays, the intensity of which is calculated by a computer using ray tracing based on a three-dimensional light field model to be displayed; wherein the intensity of the outgoing light rays carries RGB information of different intensities; and a metasurface device for performing free-form stereoscopic light field modulation on the outgoing light rays to reconstruct the three-dimensional light field model to be displayed, resulting in a naked-eye visible three-dimensional light field model; the metasurface device is prepared based on superatoms and phase templates through electron beam exposure and reactive ion etching; wherein the light source device and the metasurface device are arranged sequentially along the optical path of the outgoing light rays; the outgoing light rays are collimated rays. This invention, based on metasurface devices and a light source device, has the advantages of small size, light weight, and stable structure, achieving naked-eye three-dimensional display with less limitation on viewing angle and controllable display effect. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structural architecture of the light field display system based on metasurface provided by the present invention;

[0032] Figure 2 This is one of the schematic diagrams of the metasurface structure of the metasurface device in the metasurface-based light field display system provided by the present invention;

[0033] Figure 3 This is the second schematic diagram of the metasurface structure of the metasurface device in the metasurface-based light field display system provided by the present invention;

[0034] Figure 4 This is a simulation of the directional modulation of light in an embodiment of the metasurface-based light field display system provided by the present invention (wavelength 630nm, output far field z=200mm, intensity distribution, corresponding to 9 modulation angles of the metasurface).

[0035] Figure 5 This is a simulation of the directional modulation of light in another embodiment of the metasurface-based light field display system provided by the present invention (wavelength 540nm, output far field z=200mm, intensity distribution, corresponding to a metasurface with one modulation angle);

[0036] Figure 6 This is a simulation of the directional modulation of light in another embodiment of the metasurface-based light field display system provided by the present invention (wavelength 470nm, H-polarized incident, output far field z=200mm, intensity distribution, corresponding to a metasurface with a modulation angle).

[0037] Figure 7 This is a flowchart illustrating the light field display method based on metasurfaces provided by the present invention;

[0038] Figure 8 This is a schematic diagram of the structure of the electronic device provided by the present invention.

[0039] Figure label:

[0040] 110: Light source device; 120: Metasurface device; 130: 3D image; 140: Viewpoint area; 150: Perpendicular incident light from the light source; 160: Free-form stereoscopic light field;

[0041] 810: Processor; 820: Communication interface; 830: Memory; 840: Communication bus. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0043] Metasurfaces, as novel artificial two-dimensional materials, provide abrupt electromagnetic field modulation through artificial superatoms on their surface, breaking through the electromagnetic response characteristics and bulk effects of traditional natural materials. To date, numerous applications have been achieved in controlling physical quantities such as optical complex amplitude, wavelength, and polarization. In wavefront manipulation, metasurfaces can achieve phase templates with subwavelength resolution. Metasurfaces can not only replace traditional lenses and gratings but also extend the basic Snell's laws of light reflection and refraction, enabling more complex functions as needed. Light manipulation through metasurface devices can overcome the limitations of refractive models such as lenses, while simultaneously improving the depth and viewing angle of 3D displays.

[0044] Based on this, the present invention provides a light field display system and method based on metasurfaces.

[0045] The following is combined with Figures 1-6 The present invention describes a light field display system based on metasurfaces. Figure 1 This is a schematic diagram of the structural architecture of the metasurface-based light field display system provided by the present invention, as shown below. Figure 1 As shown, the light field display system based on metasurface provided by the present invention includes a light source device 110 and a metasurface device 120;

[0046] The light source device 110 is used to emit outgoing light rays, the intensity of which is calculated by a computer based on the three-dimensional light field model to be displayed through ray tracing; wherein, the intensity of the outgoing light rays carries RGB information of different intensities;

[0047] The metasurface device 120 is used to perform free stereoscopic display of the light field modulation of the emitted light to restore the three-dimensional light field model to be displayed, thereby obtaining the three-dimensional light field model to be displayed that is visible to the naked eye; the metasurface device 120 is prepared based on superatoms and phase templates through electron beam exposure and reactive ion etching;

[0048] The light source device 110 and the metasurface device 120 are arranged sequentially in the optical path of the emitted light; the emitted light is a collimated light.

[0049] Specifically, in some embodiments, the metasurface-based light field display system provided by the present invention employs free-form stereoscopic technology. For example... Figure 1 The hardware structure of the metasurface-based light field display system consists of a metasurface device 120 and a light source device 110. 130 represents a three-dimensional image, 140 represents a viewpoint area, 150 represents perpendicular incident light from the light source, and 160 represents a free-form three-dimensional light field.

[0050] In actual operation, based on the three-dimensional light field model to be displayed, ray tracing calculations are performed by a computer to obtain outgoing rays of different intensities carrying RGB information, generating calculated and encoded planar light field information. This planar light field information is collimated by the light source device 110 and then incident on the metasurface device 120. In this process, the calculated and encoded planar light field information is displayed by the light source device 110 as a color planar image carrying RGB information of the three-dimensional light field model to be displayed.

[0051] It's important to understand that ray tracing is a reverse computation process, also known as calculating the light field. Specifically, based on the modulation rules of the light field's intensity and direction according to the metasurface design structure, a computer simulates and calculates the light field based on the 3D light field model to be displayed. In other words, the light field data is derived from computer simulation, not from photographs of real objects. Based on the calculated light field, the light source device 110, after collimation, emits outgoing light rays, which are then incident on the metasurface device 120. The metasurface device 120 modulates the outgoing light rays for free-form stereoscopic display, reconstructing the 3D light field model to be displayed, resulting in a naked-eye visible 3D light field model.

[0052] Furthermore, the specific steps of ray tracing calculation include: starting from the spatial position of the light source device 110, tracing the light rays outward to the corresponding position on the metasurface according to the collimated outward model, and calculating the angle of the light rays in space after refraction by the metasurface. The angle calculation can be completed through rendering. The rendering process can adopt different rendering schemes, such as: the integral method of volume rendering, which integrates the RGB information of the points along the ray direction; or the surface rendering method, which uses the RGB image information of the intersection point of the ray at the current angle and the front surface of the 3D object to be displayed relative to the viewpoint to encode the intensity of the outward ray from the light source.

[0053] In other embodiments, a SiO2 substrate with a metasurface structure can be attached as a modulation layer in front of the pixel array of the light source (with the direction of the emitted light beam being in front), so that each sub-pixel of the light source corresponds to an independent metasurface modulation region. Within the ideal viewpoint area 140, the observer can move arbitrarily to observe the free stereoscopic three-dimensional image 130.

[0054] It is important to understand that the emitted light from the light source device 110 needs to be collimated. This is a requirement of the metasurface device 120 for the incident light source. The metasurface device 120 can only modulate the emission direction of collimated light.

[0055] Furthermore, the metasurface device 120 modulates the light emitted from the planar light field to reconstruct the three-dimensional light field model to be displayed. In some embodiments of the present invention, the light field display employs free-form stereoscopic technology. In specific implementation, the metasurface device 120 directionally refracts the directly emitted light, generating free-form stereoscopic light fields in different directions in space, ultimately obtaining the three-dimensional light field model to be displayed that is visible to the naked eye. Since the metasurface device 120 can modulate the directly emitted light in any direction and intensity, the emitted light is not limited by the focal length and refraction angle of traditional lens optical models. Therefore, the three-dimensional viewing angle can be arbitrarily expanded within a certain range without reducing the display depth.

[0056] The metasurface device 120 uses silicon nitride (Si3N4) material and is designed based on superatoms and phase template optimization. It is fabricated via electron beam lithography and reactive ion etching. Furthermore, the metasurface design is based on superatoms (… Figure 1 The cylindrical structure on the metasurface device 120 and the phase template optimization. The superatomic structure has different near-field phase modulation functions. The target phase template is obtained according to the preset viewing angle and optimization algorithm. Superatoms of different sizes are arranged to form a metasurface that conforms to the target phase template.

[0057] To achieve the above objectives, the light source device 110 and the metasurface device 120 are arranged sequentially in the optical path of the emitted light, as follows: Figure 1 .

[0058] The metasurface-based light field display system provided by this invention can display full-color, dynamic, and spatially accurate stereoscopic images, allowing for free viewing of the stereoscopic effect without the naked eye. Furthermore, the system boasts advantages such as small size, light weight, stable structure, controllable display effect, and the ability to overcome the viewing angle limitations imposed by the light models of traditional optical devices. It can calculate and generate dynamic stereoscopic images that can be viewed from any spatial location from any form of stereoscopic image data, such as slice tomographic scans obtained by computer-aided computed tomography (CT) or magnetic resonance imaging (MRI), as well as 3D graphic data modeled by 3D software.

[0059] In some embodiments, the light source device 110 includes a preset number of light source sub-pixels, and the metasurface device 120 includes a preset number of independent metasurface modulation regions; wherein each light source sub-pixel of the light source device 110 corresponds to an independent metasurface modulation region of the metasurface device 120.

[0060] Specifically, a SiO2 substrate with a metasurface structure can be attached as a modulation layer in front of the pixel array of the light source device 110 (with the light path direction of the emitted light being in front), so that each sub-pixel of the light source corresponds to an independent metasurface modulation region. Within an ideal viewpoint area, the observer can move arbitrarily to observe a free-form stereoscopic three-dimensional image.

[0061] In some embodiments, the light source device 110 uses collimated backlighting to illuminate a three-color filter or collimated LED self-illumination.

[0062] Specifically, the collimation of the emitted light from the light source device 110 can be achieved by illuminating with collimated backlight or by using a collimated LED light source. Since the emitted light needs to carry RGB information, the light source device 110 needs to be able to emit light of different intensities of RGB colors, for example, by illuminating a three-color filter with backlight or by using self-emissive LEDs.

[0063] In some embodiments, the metasurface device 120 is fabricated based on superatoms and a phase template via electron beam exposure and reactive ion etching, specifically including the following steps:

[0064] S1: Calculate the target angle range of the emitted light rays from the free stereoscopic light field based on the target viewing point area of ​​the stereoscopic holographic light field in space; the target angle range is denoted as the emitted light field.

[0065] S2: The metasurface device 120 is converted into a phase template and simulated to obtain a target phase template, which can modulate the incident light field of the light source device 110 into an outgoing light field.

[0066] S3: Based on a pre-built superatomic database, the superatomic size is used as the pixel size, and the elements are arranged according to the target phase template to obtain the metasurface required for a single sub-pixel;

[0067] Repeat steps S1-S3 for all the subpixels to obtain the metasurface structure of the entire display area;

[0068] Metasurface devices 120 are prepared by combining electron beam lithography or photolithography with reactive ion etching.

[0069] In some embodiments, the metasurface device 120 is fabricated using silicon nitride or silicon dioxide.

[0070] Specifically, the metasurface device 120 uses silicon nitride (Si3N4) material, is designed based on superatoms and phase template optimization, and is fabricated by electron beam lithography and reactive ion etching. In other embodiments, the modulation layer of the SiO2 substrate with metasurface structure, which is attached in front of the pixel array of the light source (with the optical path direction of the emitted light in front), can also be fabricated using the same method.

[0071] Metasurface design is based on superatoms ( Figure 1 The cylindrical structure on the metasurface device 120 and the phase template optimization. The superatomic structure has different near-field phase modulation functions. The target phase template is obtained according to the preset viewing angle and optimization algorithm. Superatoms of different sizes are arranged to form a metasurface that conforms to the target phase template.

[0072] The specific design and fabrication steps of the metasurface are as follows:

[0073] a. First, a superatomic database is constructed by designing a series of superatomic structures of different sizes, each with different near-field phase modulations. Specifically, FDTD is used to calculate the phase modulation and transmittance of superatoms of different sizes; by adjusting the parameters, a series of superatomic data with the same period and height, high transmittance (e.g., greater than 0.7), and phase modulation covering [0, 2π] are obtained, thus creating a pre-constructed superatomic database.

[0074] b. Based on the target viewing point area (generally the optimal viewing point area) of the stereoscopic holographic light field in space, calculate the angular range of the emitted light rays from the free stereoscopic light field, corresponding to the position of each modulation unit on the metasurface. Therefore, each modulation unit needs to modulate the incident light field of the light source to a defined target angular range, denoted as the emitted light field.

[0075] c. Abstract the metasurface into a phase template and perform simulation design. Using a lens and a blazed grating as the basic templates, a suitable target phase template is obtained through a gradient descent optimization algorithm. The resulting target phase template can modulate the incident light field into the target's outgoing light field.

[0076] d. Next, using a pre-built superatomic database, metasurfaces with phase distributions as close as possible to the target phase template are arranged using superatomic dimensions as pixel sizes. This yields the metasurface required for a single subpixel. Applying the same steps to all subpixels yields the metasurface structure for the entire display area.

[0077] e. Metasurfaces are prepared by combining electron beam lithography / photolithography with reactive ion etching.

[0078] A schematic diagram of the designed metasurface is shown below. Figure 2 and Figure 3 As shown.

[0079] In one embodiment, after the collimated backlight is modulated by a metasurface, the RGB far-field light intensity at different viewing angles is obtained in the simulation, such as... Figure 4 As shown in the red backlight, the beam wavelength is 630nm, the output far-field z = 200mm, and the intensity distribution corresponds to a metasurface with 9 modulation angles; the simulation parameters include:

[0080] Figure 4 (a): Beam wavelength is 0.63000 μm, medium refractive index is 1.00000@0.0000 (degrees), display X width = 4.2966E+03, Y height = 4.2966E+03 mm, peak irradiance = 2.1988E+03 watts / mm². 2 Total power = 1.3956E+06 watts, Pilot: size = 2.3602E+00, beam waist = 1.6993E-02, position = 2.0000E+02, Rayleigh length = 1.4400E+00, beam width X = 1.10647E+02, Y = 1.60688E+02 mm.

[0081] Figure 4 (b): Beam wavelength is 0.63000 μm, medium refractive index is 1.00000@0.0000 (degrees), display X width = 4.2966E+03, Y height = 4.2966E+03 mm, peak irradiance = 2.6539E+03 watts / mm². 2 Total power = 1.4066E+06 watts, Pilot: size = 2.3549E+00, beam waist = 1.7032E-02, position = 2.0000E+02, Rayleigh length = 1.4466E+00, beam width X = 4.84356E+01, Y = 1.59935E+02 mm.

[0082] Figure 4 (c): Beam wavelength is 0.63000 μm, medium refractive index is 1.00000@0.0000 (degrees), display X width = 4.2966E+03, Y height = 4.2966E+03 mm, peak irradiance = 2.3964E+03 watts / mm². 2 Total power = 1.3972E+06 watts, Pilot: size = 2.3602E+00, beam waist = 1.6993E-02, position = 2.0000E+02, Rayleigh length = 1.4400E+00, beam width X = 1.08315E+02, Y = 1.60709E+02 mm.

[0083] Figure 4(d): Beam wavelength is 0.63000 μm, medium refractive index is 1.00000@0.0000 (degrees), display X width = 4.2966E+03, Y height = 4.2966E+03 mm, peak irradiance = 2.3219E+03 watts / mm². 2 Total power = 1.1939E+06 watts, Pilot: size = 2.3580E+00, beam waist = 1.7010E-02, position = 2.0000E+02, Rayleigh length = 1.4428E+00, beam width X = 1.04132E+02, Y = 9.19480E+01 mm.

[0084] Figure 4 (e): Beam wavelength is 0.63000 μm, medium refractive index is 1.00000@0.0000 (degrees), display X width = 4.2966E+03, Y height = 4.2966E+03 mm, peak irradiance = 2.6493E+03 watts / mm². 2 Total power = 1.2781E+06 watts, Pilot: size = 2.3508E+00, beam waist = 1.7061E-02, position = 2.0000E+02, Rayleigh length = 1.4515E+00, beam width X = 4.17023E+01, Y = 1.13391E+02 mm.

[0085] Figure 4 (f): Beam wavelength is 0.63000 μm, medium refractive index is 1.00000@0.0000 (degrees), display X width = 4.2966E+03, Y height = 4.2966E+03 mm, peak irradiance = 2.5343E+03 watts / mm². 2 Total power = 1.1964E+06 watts, Pilot: size = 2.3589E+00, beam waist = 1.7003E-02, position = 2.0000E+02, Rayleigh length = 1.4416E+00, beam width X = 1.01557E+02, Y = 9.34278E+01 mm.

[0086] Figure 4 (g): Beam wavelength is 0.63000 μm, medium refractive index is 1.00000@0.0000 (degrees), display X width = 4.2966E+03, Y height = 4.2966E+03 mm, peak irradiance = 2.0010E+03 watts / mm². 2Total power = 1.3965E+06 watts, Pilot: size = 2.3603E+00, beam waist = 1.6993E-02, position = 2.0000E+02, Rayleigh length = 1.4399E+00, beam width X = 1.10881E+02, Y = 1.61997E+02 mm.

[0087] Figure 4 (h): Beam wavelength is 0.63000μm, medium refractive index is 1.00000@0.0000 (degrees), display X width = 4.2966E+03, Y height = 4.2966E+03 mm, peak irradiance = 2.4299E+03 watts / mm². 2 Total power = 1.4049E+06 watts, Pilot: size = 2.3545E+00, beam waist = 1.7035E-02, position = 2.0000E+02, Rayleigh length = 1.4471E+00, beam width X = 4.83467E+01, Y = 1.61145E+02 mm.

[0088] Figure 4 (i): Beam wavelength is 0.63000 μm, medium refractive index is 1.00000@0.0000 (degrees), display X width = 4.2966E+03, Y height = 4.2966E+03 mm, peak irradiance = 2.1838E+03 watts / mm². 2 Total power = 1.3983E+06 watts, Pilot: size = 2.3602E+00, beam waist = 1.6994E-02, position = 2.0000E+02, Rayleigh length = 1.4401E+00, beam width X = 1.08565E+02, Y = 1.62056E+02 mm.

[0089] In another embodiment, after the collimated backlight is modulated by a metasurface, the RGB far-field light intensity at different viewing angles is obtained in the simulation, such as... Figure 5 (Green backlight) as shown; the simulation parameters include: beam wavelength of 0.54000μm, medium refractive index of 1.00000@0.0000 (degrees), display X width = 7.3692E+03, Y height = 7.3692E+03 mm, peak irradiance = 8.0131E+03 watts / mm². 2 Total power = 5.1272E+06 watts, Pilot: size = 2.0120E+00, beam waist = 1.7087E-02, position = 2.0000E+02, Rayleigh length = 1.6986E+00, beam width X = 1.30370E+02, Y = 1.60748E+02 mm.

[0090] In another embodiment, after the collimated backlight is modulated by a metasurface, the RGB far-field light intensity at different viewing angles is obtained in the simulation, such as... Figure 6 (As shown in blue backlight); the simulation parameters include: beam wavelength of 0.47000μm, medium refractive index of 1.00000@0.0000 (degrees), display X width = 6.4139E+03, Y height = 6.4139E+03 mm, and peak irradiance = 7.4333E+03 watts / mm². 2 Total power = 4.1316E+06 watts, Pilot: size = 1.7493E+00, beam waist = 1.7105E-02, position = 2.0000E+02, Rayleigh length = 1.9557E+00, beam width X = 1.48026E+02, Y = 1.56545E+02 mm.

[0091] Simulation results show that, through modulation of several metasurface structures, the collimated backlight can be directed to different locations in space, possessing the light field modulation performance for free stereoscopic display.

[0092] This invention provides a metasurface-based light field display system, comprising: a light source device 110 for emitting outgoing light rays, the intensity of which is calculated by a computer based on a three-dimensional light field model to be displayed via ray tracing; wherein the intensity of the outgoing light rays carries RGB information of different intensities; and a metasurface device 120 for performing free-form stereoscopic light field modulation on the outgoing light rays to reconstruct the three-dimensional light field model to be displayed, thereby obtaining a naked-eye visible three-dimensional light field model; the metasurface device 120 is fabricated based on superatoms and phase templates through electron beam exposure and reactive ion etching; wherein the light source device 110 and the metasurface device 120 are arranged sequentially along the optical path of the outgoing light rays; the outgoing light rays are collimated rays. This invention, based on the metasurface device 120 and the light source device 110, has the advantages of small size, light weight, and stable structure, achieving naked-eye three-dimensional display with less limitation on viewing angle and controllable display effect.

[0093] The metasurface-based light field display method provided by the present invention is described below. The metasurface-based light field display method described below and the metasurface-based light field display system described above can be referred to and correspond to each other.

[0094] Figure 7 This is a flowchart illustrating the light field display method based on metasurfaces provided by the present invention, as shown below. Figure 7 As shown, the light field display method based on metasurfaces provided by the present invention includes:

[0095] Step 210: Obtain the 3D light field model to be displayed;

[0096] Step 220: Based on the three-dimensional light field model to be displayed, use a computer to perform ray tracing calculations to obtain outgoing rays of different intensities carrying RGB information;

[0097] Step 230: Modulate the light field of the emitted light rays for free stereoscopic display to restore the three-dimensional light field model to be displayed, and obtain the three-dimensional light field model to be displayed that is visible to the naked eye;

[0098] The emitted light ray is a collimated light ray.

[0099] Specifically, in some embodiments, the metasurface-based light field display method provided by the present invention employs free-form stereoscopic technology. First, a three-dimensional light field model to be displayed needs to be obtained. It should be noted that the light field model to be displayed is not visible to the naked eye.

[0100] Based on the three-dimensional light field model to be displayed, ray tracing calculations are performed by a computer to obtain outgoing rays of different intensities carrying RGB information, generating calculated and encoded planar light field information. In this process, the calculated and encoded planar light field information is represented by the light source device 110 displaying a colored planar image of the three-dimensional light field model to be displayed, carrying RGB information. It is important to understand that ray tracing calculation is a reverse calculation process, also known as the process of calculating the light field. Specifically, based on the modulation rules of the intensity and direction of the light field by the metasurface design structure, the computer simulates and calculates the calculated light field according to the three-dimensional light field model to be displayed. In other words, the light field data is obtained through computer simulation calculations, rather than through photographing real objects.

[0101] Furthermore, the specific steps of ray tracing calculation include: starting from the spatial position of the light source device 110, tracing the light rays to the corresponding position on the metasurface according to the collimated emission model, and calculating the angle of the light rays after refraction by the metasurface in space. The angle calculation can be completed through rendering. The rendering process can employ different rendering schemes, such as: volume rendering integration methods, integrating the RGB information of points along the light direction; or surface rendering methods, using the RGB image information of the intersection point of the light rays at the current angle and the front surface of the 3D object to be displayed relative to the viewpoint to encode the intensity of the emitted light rays. In other words, based on the 3D light field model to be displayed, and according to the intensity and direction modulation rules of the light field designed by the metasurface device 120, based on the spatial position of the light source device 110 and the collimated emission model, the computer performs a reverse calculation of the free-form 3D light field model to obtain the calculated light field. The light source device 110 emits emitted light rays according to the calculated light field, and then the emitted light rays are modulated for free-form 3D display to reconstruct the 3D light field model to be displayed, resulting in the naked-eye visible 3D light field model. The emitted light is emitted by the light source device 110 and is collimated light.

[0102] In some embodiments, the ray tracing calculation includes:

[0103] Based on the preset structure of the metasurface device 120, the angle of the light rays after refraction through the metasurface in space is calculated, and the emitted light rays are encoded in RGB and light intensity according to the angle of the light rays in space and the three-dimensional light field model to be displayed.

[0104] Specifically, the intensity of the emitted light from the light source device 110 encodes the compressed information of the free-form light field. Through ray tracing calculations performed by a computer, the light intensity information is finally encoded into an RGB true-color image.

[0105] Ray tracing is a reverse computation process, also known as calculating the light field. Specifically, based on the modulation rules of the light field's intensity and direction caused by the metasurface design structure, a computer simulates and calculates the light field according to the 3D light field model to be displayed. In other words, the light field data is derived from computer simulation, not from photographs of real objects.

[0106] Furthermore, the specific steps of ray tracing calculation include: starting from the spatial position of the light source device 110, calculating the angle of the light rays after refraction by the metasurface according to the collimated emission model and the corresponding position of the light rays emitted from the metasurface. The angle calculation can be completed through rendering. The rendering process can adopt different rendering schemes, such as: the integral method of volume rendering, which integrates the RGB information of the points in the direction of the light rays; or the surface rendering method, which uses the RGB image information of the intersection point of the light rays at the current angle and the front surface of the three-dimensional object to be displayed relative to the viewpoint to encode the intensity of the emitted light rays from the light source. That is, according to the three-dimensional light field model to be displayed, according to the intensity and direction modulation rules of the light field designed by the metasurface device 120, and based on the spatial position of the light source device 110 and the collimated emission model, the computer is used to perform reverse calculation of the free-form three-dimensional light field model to obtain the calculated light field.

[0107] In some embodiments, the light field modulation for free stereoscopic display of the emitted light specifically includes:

[0108] Based on the preset structure of the metasurface device 120, the emitted light is refracted in a directional manner to modulate the intensity and direction of the light field, thereby generating free three-dimensional light fields in different directions in space.

[0109] Specifically, the metasurface device 120 modulates the light emitted from the planar light field to reconstruct the three-dimensional light field model to be displayed. In the specific implementation process, after the metasurface device 120 directionally refracts the directly emitted light, it generates free three-dimensional light fields in different directions in space, ultimately obtaining the three-dimensional light field model to be displayed that is visible to the naked eye. Since the metasurface device 120 can modulate the directly emitted light in any direction and intensity, the emitted light is not limited by the focal length and refraction angle of traditional lens optical models. Therefore, the three-dimensional viewing angle can be arbitrarily expanded within a certain range without reducing the display depth. The metasurface device 120 uses silicon nitride (Si3N4) material, is designed based on superatoms and phase template optimization, and is fabricated through electron beam exposure and reactive ion etching. The metasurface design is based on superatoms (Si3N4). Figure 1 The cylindrical structure on the metasurface device 120 and the phase template optimization. The superatomic structure has different near-field phase modulation functions. The target phase template is obtained according to the preset viewing angle and optimization algorithm. Superatoms of different sizes are arranged to form a metasurface that conforms to the target phase template.

[0110] This invention provides a metasurface-based light field display method. The method involves acquiring a three-dimensional light field model to be displayed; calculating, using a computer, outgoing rays of different intensities carrying RGB information based on the model; and modulating the outgoing rays for free-view stereoscopic display to reconstruct the three-dimensional light field model, resulting in a naked-eye visible model. The outgoing rays are collimated. Based on a metasurface device 120 and a light source device 110, this invention offers advantages such as small size, light weight, and structural stability, enabling naked-eye three-dimensional display with less viewing angle restriction and controllable display effects.

[0111] Figure 8 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 8 As shown, the electronic device may include a processor 810, a communication interface 820, a memory 830, and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other via the communication bus 840. The processor 810 can call logical instructions in the memory 830 to execute a metasurface-based light field display method. This method includes: acquiring a three-dimensional light field model to be displayed; performing ray tracing calculations using a computer to obtain outgoing rays of different intensities carrying RGB information based on the three-dimensional light field model; performing free stereoscopic light field modulation on the outgoing rays to reconstruct the three-dimensional light field model to be displayed, thereby obtaining a naked-eye visible three-dimensional light field model; wherein the outgoing rays are collimated rays.

[0112] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0113] On another front, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, this computer program implements the metasurface-based light field display method provided by the above-described methods. This method includes: acquiring a three-dimensional light field model to be displayed; calculating, using a computer, outgoing rays carrying RGB information of different intensities through ray tracing based on the three-dimensional light field model to be displayed; performing free stereoscopic light field modulation on the outgoing rays to reconstruct the three-dimensional light field model to be displayed, thereby obtaining a naked-eye visible three-dimensional light field model; wherein the outgoing rays are collimated rays. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, i.e., they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0114] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light field display system based on metasurfaces, characterized in that, include: A light source device is provided, which emits outgoing light rays. The intensity of the outgoing light rays is calculated by a computer based on a three-dimensional light field model to be displayed, through ray tracing. The intensity of the outgoing light rays carries RGB information of different intensities. The ray tracing calculation includes: calculating the angle of the light rays after refraction through the metasurface in space based on the preset structure of the metasurface device; and encoding the outgoing light rays in RGB and light intensity according to the angle of the light rays in space and the three-dimensional light field model to be displayed. A metasurface device is used to modulate the light field of the emitted light in a free stereoscopic display to reconstruct the three-dimensional light field model to be displayed, thereby obtaining the three-dimensional light field model visible to the naked eye. The metasurface device is prepared based on superatoms and phase templates through electron beam exposure and reactive ion etching. The metasurface device is designed by calculating the angular range of the emitted light from the free stereoscopic light field according to the target viewing point area of ​​the stereoscopic holographic light field in space, and by reverse design through phase template simulation design and superatom database arrangement. The light source device and the metasurface device are arranged sequentially in the optical path of the emitted light; the emitted light is a collimated light.

2. The light field display system based on metasurfaces according to claim 1, characterized in that, The light source device includes a preset number of light source sub-pixels, and the metasurface device includes a preset number of independent metasurface modulation regions; wherein, each light source sub-pixel of the light source device corresponds to an independent metasurface modulation region of the metasurface device.

3. The light field display system based on metasurface according to claim 2, characterized in that, The metasurface device is fabricated based on superatoms and a phase template through electron beam exposure and reactive ion etching, specifically including the following steps: S1: The target angle range is denoted as the emitted light field; S2: The target phase template can modulate the incident light field of the light source device into an outgoing light field; S3: Based on a pre-built superatomic database, the superatomic size is used as the pixel size, and the elements are arranged according to the target phase template to obtain the metasurface required for a single sub-pixel; Repeat steps S1-S3 for all the subpixels to obtain the metasurface structure of the entire display area; Metasurface devices are prepared by combining electron beam lithography or photolithography with reactive ion etching.

4. The light field display system based on metasurfaces according to claim 1, characterized in that, The metasurface device is made of silicon nitride or silicon dioxide.

5. The light field display system based on metasurfaces according to claim 1, characterized in that, The light source device adopts collimated backlighting of a three-color filter or collimated LED self-illumination.

6. A metasurface-based light field display method, based on the metasurface-based light field display system as described in any one of claims 1-5, characterized in that, The method includes: Obtain the 3D light field model to be displayed; Based on the three-dimensional light field model to be displayed, the emitted light rays with different intensities carrying RGB information are obtained by ray tracing calculation using a computer. The emitted light rays are subjected to free stereoscopic display light field modulation to restore the three-dimensional light field model to be displayed, thereby obtaining the three-dimensional light field model to be displayed that is visible to the naked eye; The emitted light ray is a collimated light ray.

7. The light field display method based on metasurfaces according to claim 6, characterized in that, The light field modulation for free stereoscopic display of the emitted light specifically includes: Based on the preset structure of the metasurface device, the emitted light is refracted in a directional manner to modulate the intensity and direction of the light field, thereby generating a free three-dimensional light field in different directions in space.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the metasurface-based light field display method as described in claim 6 or 7.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the metasurface-based light field display method as described in claim 6 or 7.

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