Naked-eye binocular stereoscopic display system and method based on metasurface polarization beam splitting modulation

Abstract

The application provides a naked-eye binocular stereoscopic display system and method based on metasurface polarization beam splitting modulation, wherein the system comprises: a light source device for calculating a target image by ray tracing calculation according to a three-dimensional image, and determining a first emergent light based on the target image; a polarization modulation device for performing polarization state modulation on the first emergent light to obtain a second emergent light; and a metasurface device for performing polarization beam splitting on the second emergent light to obtain a naked-eye visible binocular stereoscopic image corresponding to the three-dimensional image. The system can split the collimated plane light source into directional light rays with double information based on the polarization beam splitting function of the metasurface device to generate binocular parallax. Compared with the traditional binocular stereoscopic display technology, the system can realize naked-eye binocular stereoscopic parallax three-dimensional display without loss of plane resolution, and has the advantages of small volume, light weight, stable structure and no need for the viewer to wear additional equipment.

Description

Technical Field

[0001] This invention relates to the field of computer image display technology, and in particular to a naked-eye binocular stereoscopic display system and method based on metasurface polarization beam splitting modulation. Background Technology

[0002] Ordinary planar light source devices can only display two-dimensional information and cannot provide visual depth perception. However, by adding binocular parallax, the observer can directly observe a three-dimensional image with physical depth, thus bringing a sense of stereoscopic vision.

[0003] For example, VR / AR and stereoscopic movies create a sense of binocular parallax by displaying different images on two eyes. These technologies offer high resolution and a strong sense of immersion, but require the use of auxiliary devices, which can cause additional burdens such as visual and physical fatigue for the observer. Achieving naked-eye binocular stereoscopic display would effectively improve the viewing experience.

[0004] Currently, naked-eye stereoscopic vision solutions mainly employ lens-based or holographic-based technologies. However, lens-based technologies significantly compress the resolution of 3D displays, while holographic technologies struggle to achieve dynamic color display effects. Summary of the Invention

[0005] This invention provides a naked-eye binocular stereoscopic display system and method based on metasurface polarization beam splitting modulation, which overcomes the shortcomings of existing binocular stereoscopic display technology that compresses the resolution of three-dimensional display and cannot achieve dynamic color display effects, thereby realizing three-dimensional display with naked-eye binocular stereoscopic parallax.

[0006] On one hand, the present invention provides a naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation, comprising: a light source device, which is used to obtain a target image by ray tracing calculation based on a three-dimensional image, and to determine a first outgoing ray based on the target image, wherein the target image is two images encoded with binocular stereoscopic parallax; a polarization modulation device, which is used to modulate the polarization state of the first outgoing ray to obtain a second outgoing ray; and a metasurface device, which is used to perform polarization beam splitting on the second outgoing ray to obtain a naked-eye visible binocular stereoscopic image corresponding to the three-dimensional image; wherein the light source device, the polarization modulation device, and the metasurface device are arranged sequentially in the optical path of the first outgoing ray, the first outgoing ray is a collimated ray, and the metasurface device is prepared based on superatoms and a phase modulation template by electron beam exposure and reactive ion etching.

[0007] Furthermore, the light source device includes a preset number of light source sub-pixels, and the metasurface device includes the preset number of metasurface modulation units; wherein each light source sub-pixel corresponds one-to-one with each metasurface modulation unit.

[0008] Furthermore, the metasurface device corresponds to a first phase modulation template and a second phase modulation template. The first phase modulation template is used to orient the horizontal polarization component of the second emitted light to the first region, and the second phase modulation template is used to orient the vertical polarization component of the second emitted light to the second region.

[0009] Furthermore, the metasurface device is fabricated using silicon nitride or silicon dioxide.

[0010] Furthermore, the light source device is used to generate collimated light by illuminating a three-color filter with collimated backlight or by collimating a self-emissive LED.

[0011] Secondly, the present invention also provides a naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting modulation, based on the naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation as described above, comprising: obtaining a target image by ray tracing calculation based on a three-dimensional image, and determining a first outgoing ray based on the target image, wherein the target image is two images encoded with binocular stereoscopic parallax, and the first outgoing ray is a collimated ray; performing polarization state modulation on the first outgoing ray to obtain a second outgoing ray; and performing polarization beam splitting on the second outgoing ray based on a metasurface device to obtain a naked-eye visible binocular stereoscopic image corresponding to the three-dimensional image.

[0012] Furthermore, the fabrication steps of the metasurface device specifically include: calculating the required light divergence angle and deflection angle based on the relative positions of the light source sub-pixel and the observer's binoculars; determining a first phase modulation template and a second phase modulation template based on the light divergence angle and deflection angle, wherein the first phase modulation template is used to orient the horizontal polarization component of the second emitted light to a first region, and the second phase modulation template is used to orient the vertical polarization component of the second emitted light to a second region; arranging the first and second phase modulation templates according to a pre-constructed metaatom database with the metaatom size as the pixel size to obtain the metasurface structure of the entire display area; and fabricating the metasurface device by electron beam exposure or photolithography combined with reactive ion etching based on the metasurface structure.

[0013] Furthermore, the expressions for the first phase modulation template and the second phase modulation template are as follows:

[0014]

[0015]

[0016] in, As the first phase modulation template, As the second phase modulation template, f x,HH and f x,VV All are horizontal lens focal lengths, f y,HH and f y,VV All are vertical lens focal lengths, θ x,HH and θ x,VV All are horizontal deflection angles, θ y,HH and θ y,VV All are vertical deflection angles, x and y are spatial coordinates, and k is the wave vector of the plane wave.

[0017] Further, the step of calculating the target image by ray tracing based on the three-dimensional image and determining the first outgoing ray based on the target image includes: calculating the target image by ray tracing based on the ray divergence angle and deflection angle, wherein the target image includes a left-eye channel plane image corresponding to the observer's left eye and a right-eye channel plane image corresponding to the observer's right eye; and calculating the light intensity of the first outgoing ray based on the light intensity of the left-eye channel outgoing ray corresponding to the left-eye channel plane image and the light intensity of the right-eye channel outgoing ray corresponding to the right-eye channel plane image.

[0018] Furthermore, the polarization beam splitting and intensity modulation of the second emitted light includes: collimating the second emitted light to the binocular region based on the metasurface structure of the metasurface device, so as to complete the polarization beam splitting of the second emitted light.

[0019] Furthermore, the polarization state modulation of the first emitted light includes: determining the linear polarization angle using a polarization state calculation formula; and performing polarization state modulation on the first emitted light according to the determined linear polarization angle.

[0020] Furthermore, the formula for calculating the polarization state is as follows:

[0021]

[0022] Where β is the linear polarization angle, I H The intensity of light emitted from the left eye channel, I V The intensity of light emitted from the right eye channel.

[0023] Further, the step of calculating the light intensity of the first emitted ray based on the light intensity emitted from the left eye channel corresponding to the left eye channel planar image and the light intensity emitted from the right eye channel corresponding to the right eye channel planar image includes: determining the light intensity of the first emitted ray according to a preset formula, the preset formula being as follows:

[0024]

[0025] Where I is the intensity of the first emitted ray, I H The intensity of light emitted from the left eye channel, I V The intensity of light emitted from the right eye channel.

[0026] Thirdly, 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 naked-eye binocular stereoscopic display method based on metasurface beam splitting modulation as described above.

[0027] Fourthly, 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 naked-eye binocular stereoscopic display method based on metasurface beam splitting modulation as described above.

[0028] This invention provides a naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation, comprising a light source device, a polarization modulation device, and a metasurface device. The light source device calculates a target image based on a 3D image using ray tracing and determines a first emitted ray based on the target image. The polarization modulation device modulates the polarization state of the first emitted ray to obtain a second emitted ray, allowing the polarization angle of the second emitted ray to be arbitrarily adjusted. The metasurface device performs polarization beam splitting on the second emitted ray, thereby obtaining a naked-eye visible binocular stereoscopic image corresponding to the 3D image. Based on the polarization beam splitting function of the metasurface device, this system can split a collimated planar light source into directional rays with twice the information, generating binocular parallax. Compared to traditional naked-eye binocular stereoscopic display technology, this system does not lose planar resolution and has the advantages of small size, light weight, stable structure, and no need for viewers to wear additional devices, achieving 3D display with naked-eye binocular stereoscopic parallax. Attached Figure Description

[0029] 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.

[0030] Figure 1 A schematic diagram of the naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting provided by the present invention;

[0031] Figure 2This is a flowchart illustrating the naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting provided by the present invention.

[0032] Figure 3 One of the schematic diagrams of the metasurface structure of the metasurface device provided by the present invention;

[0033] Figure 4 The second schematic diagram of the metasurface structure of the metasurface device provided by the present invention;

[0034] Figure 5 This is one of the polarization beam splitting schematic diagrams of metasurface polarization beam splitting modulation provided by the present invention;

[0035] Figure 6 The second schematic diagram of polarization beam splitting modulation of metasurface provided by the present invention;

[0036] Figure 7 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0037] 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.

[0038] It should be noted that metasurfaces, as a novel type of artificial two-dimensional material, provide abrupt electromagnetic field modulation through artificial superatoms on the surface, breaking through the electromagnetic response characteristics and bulk effects of traditional natural materials.

[0039] To date, numerous applications have been developed for 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 reflection and refraction to achieve more complex functions as needed.

[0040] In addition, polarization-related metasurface technology is becoming increasingly mature, supporting the polarization control of superatoms to achieve multiple functions; thus, metasurfaces can be used to simultaneously manipulate the polarization degree of freedom and phase of light, realizing polarization multiplexing in three-dimensional displays and increasing the amount of information displayed with the same number of pixels.

[0041] Based on the above, embodiments of the present invention provide a naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation, specifically, Figure 1A schematic diagram of the naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation provided by the present invention is shown.

[0042] like Figure 1 As shown, the naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation provided by the present invention includes:

[0043] The light source device 110 is used to obtain a target image by ray tracing calculation based on a three-dimensional image, and to determine a first outgoing ray based on the target image, wherein the target image is two images encoded with binocular stereo parallax;

[0044] A polarization modulation device 120 is used to modulate the polarization state of the first outgoing light to obtain a second outgoing light.

[0045] Metasurface device 130 is used to polarize and split the second outgoing light beam to obtain a naked-eye visible binocular stereo image corresponding to the three-dimensional image.

[0046] exist Figure 1 In the middle, γ x,HH and γ x,VV θ is the divergence angle corresponding to the binocular region. x,HH and θ x,VV This represents the deflection angle corresponding to the binocular region.

[0047] Among them, the light source device 110, the polarization modulation device 120 and the metasurface device 130 are arranged sequentially in the optical path of the first emitted light. The first emitted light is a collimated light. The metasurface device 130 is prepared based on superatoms and phase modulation templates by electron beam exposure and reactive ion etching.

[0048] Specifically, according to Figure 1 As can be seen, the system consists of a light source device 110, a polarization modulation device 120, and a metasurface device 130.

[0049] In one specific embodiment, the light source device 110 includes a preset number of light source sub-pixels, and the metasurface device 130 includes a preset number of metasurface modulation units, with each light source sub-pixel corresponding one-to-one with each metasurface modulation unit. The preset number can be set according to actual conditions and is not specifically limited here.

[0050] In actual binocular stereoscopic image display, the light source device 110 can emit outgoing light of different intensities in RGB colors. After the light source device 110 generates outgoing light, it needs to be collimated. In a specific embodiment, the light source device 110 can generate collimated light by illuminating a three-color filter with collimated backlight or by collimating a self-emissive LED.

[0051] It should be noted that the light source device 110 includes multiple light source sub-pixels. For a single light source sub-pixel, the emitted light is monochromatic and linearly polarized light with a single polarization angle, and the intensity of the linearly polarized light can be arbitrarily adjusted.

[0052] After collimation, the emitted light from the light source device 110 is used to calculate two planar images corresponding to the left and right eye channels of the observer based on the three-dimensional image corresponding to the binocular stereo image to be displayed. Then, the first emitted light ray α is determined based on these two planar images. It should be noted that the first emitted light ray is encoded with two images of binocular stereo parallax, and these two images correspond to the light intensity of the binocular region respectively.

[0053] It should be noted that ray tracing calculation is a reverse calculation. Starting from the light source device 110, the light is emitted to the polarization modulation device 120 according to the collimated emission model, and then emitted to the corresponding position on the metasurface. The angle of the light in space after refraction by the metasurface is calculated.

[0054] The angle calculation is completed during the image rendering process, which can employ different rendering schemes. In one specific embodiment, a pixel-integrated volume rendering method can be used, which integrates the RGB information of points along the light path. In another specific embodiment, a surface-based rendering method can be used, which encodes the intensity of the emitted light from the light source using the RGB image information of the intersection point of the light ray at the current angle and the front surface of the stereoscopic image to be displayed relative to the viewpoint.

[0055] It should also be noted that the two images with binocular stereo parallax described above can be encoded by computer calculation of the required 3D scene depth and rendering the corresponding viewing distance in physical space from the camera's perspective. Alternatively, the parallax portion of the planar image can be segmented and filled using deep learning and manual segmentation to generate a parallax map.

[0056] Subsequently, the first emitted light from the light source device 110 is incident on the polarization modulation device 120 with a single-angle polarization state. The polarization modulation device 120 modulates the polarization angle of the first emitted light according to the pre-calculated linear polarization angle β to obtain the second emitted light, so that the polarization angle of the second emitted light can be arbitrarily adjusted.

[0057] In one specific embodiment, a polarization modulation device 120 is added between the light source device 110 and the metasurface device 130. The polarization modulation device 120 is a liquid crystal polarization control layer used to control the beam splitting ratio of the left and right eyes, and combined with the intensity control of pixels, to realize independent control of the light intensity of the left and right eye channels.

[0058] Furthermore, the second outgoing light obtained after polarization state modulation by polarization modulation device 120 is incident on metasurface device 130, and the metasurface device 130 polarizes and splits the second outgoing light beam. After beam splitting, the light intensity ratio of the left and right eye channels depends on the polarization state of the second outgoing light. Thus, polarization state modulation and polarization beam splitting jointly realize light intensity modulation.

[0059] It should be noted that the metasurface device 130 is fabricated based on superatoms and a phase modulation template through electron beam lithography and reactive ion etching. The metasurface device corresponds to a phase modulation template, which includes a first phase modulation template and a second phase modulation template. The first phase modulation template is used to refract the horizontal polarization component of the second emitted light into a first region, and the second phase modulation template is used to refract the vertical polarization component of the second emitted light into a second region.

[0060] Specifically, the metasurface device 130 uses polarization-dependent rectangular pillar metaatoms to generate different phase template modulation effects on collimated input light with horizontal and vertical polarization states, corresponding to two different lens-like templates, namely the first phase modulation template and the second phase modulation template mentioned above, in order to complete the directional polarization beam splitting of collimated light to binoculars.

[0061] Polarization beam splitting includes horizontal and vertical polarization beam splitting. Based on the operating characteristics of the metasurface polarization beam splitter, the horizontally upward polarization component will be split to the left eye, while the vertically upward polarization component will be split to the right eye. The specific splitting angle depends on the distance and binocular interpupillary distance. Thus, by using the two orthogonal polarization states of the second outgoing ray to correspond to the directions of the two outgoing rays, different light intensities I in two directions in space can be generated. H and I V This achieves binocular parallax, thus creating a stereoscopic vision effect.

[0062] It should be understood that, in one specific embodiment, the metasurface device 130 is fabricated using silicon nitride or silicon dioxide.

[0063] Based on the above, the naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation provided in this embodiment of the invention can be summarized as follows: based on the three-dimensional image displayed by the light source device 110, according to the polarization beam splitting and light intensity modulation rules of the second emitted light by the metasurface structure of the metasurface device 130, the computer is used to perform reverse calculation of the binocular stereoscopic image to be displayed.

[0064] according to Figure 1It can also be seen that the first emitted light is a collimated light. The light source device 110, polarization modulation device 120 and metasurface device 130 included in the system are arranged sequentially in the optical path of the first emitted light. Specifically, water-based adhesive and full lamination technology can be used to encapsulate the light source device 110, polarization modulation device 120 and metasurface device 130 in the order of their sequential arrangement.

[0065] In this embodiment, the naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation includes a light source device 110, a polarization modulation device 120, and a metasurface device 130. The light source device 110 calculates a target image based on a 3D image using ray tracing and determines a first emitted ray based on the target image. The polarization modulation device 120 modulates the polarization state of the first emitted ray to obtain a second emitted ray, allowing the polarization angle of the second emitted ray to be arbitrarily adjusted. The metasurface device 130 performs polarization beam splitting on the second emitted ray, thereby obtaining a naked-eye visible binocular stereoscopic image corresponding to the 3D image. Based on the polarization beam splitting function of the metasurface device 130, this system can split a collimated planar light source into directional rays with twice the information, generating binocular parallax. Compared to traditional binocular stereoscopic display technology, this system does not lose planar resolution and has advantages such as small size, light weight, stable structure, and no need for viewers to wear additional devices, achieving 3D display with naked-eye binocular stereoscopic parallax.

[0066] Based on the above-mentioned naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting, this embodiment of the invention also provides a naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting.

[0067] Specifically, Figure 2 A schematic flowchart of the naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting provided by the present invention is shown. Figure 2 As shown, the method includes:

[0068] S210, Based on the three-dimensional image, the target image is obtained by ray tracing calculation, and the first outgoing ray is determined based on the target image. The target image consists of two images encoded with binocular stereo parallax, and the first outgoing ray is a collimated ray.

[0069] Understandably, based on the 3D image corresponding to the stereoscopic image to be displayed, ray tracing calculations can be used to obtain two planar images corresponding to the observer's left and right eye channels. The first outgoing ray is then determined based on these two planar images. It should be noted that these two images correspond to the light intensity of the binocular regions, and the first outgoing ray is monochromatic linearly polarized light with a single polarization angle; the intensity of this linearly polarized light can be arbitrarily adjusted.

[0070] Based on the 3D image, a target image is obtained through ray tracing calculation, and a first outgoing ray is determined based on the target image. Specifically, the required ray divergence angle and deflection angle are calculated based on the relative positions of the light source sub-pixels and the observer's binoculars. Based on the ray divergence angle and deflection angle, the target image is obtained through ray tracing calculation. The target image includes a left-eye channel plane image corresponding to the observer's left eye and a right-eye channel plane image corresponding to the observer's right eye. The intensity of the first outgoing ray is calculated based on the light intensity of the left-eye channel outgoing ray corresponding to the left-eye channel plane image and the light intensity of the right-eye channel outgoing ray corresponding to the right-eye channel plane image.

[0071] Specifically, ray tracing is a reverse calculation that starts from the light source device, follows the collimated emission model to the polarization modulation device, and then emits light to the corresponding position on the metasurface to calculate the angle of the light in space after refraction by the metasurface.

[0072] The angle calculation is completed during the image rendering process, which can employ different rendering schemes. In one specific embodiment, a pixel-integrated volume rendering method can be used, which integrates the RGB information of points along the light path. In another specific embodiment, a surface-based rendering method can be used, which encodes the intensity of the emitted light from the light source using the RGB image information of the intersection point of the light ray at the current angle and the front surface of the stereoscopic image to be displayed relative to the viewpoint.

[0073] It should also be noted that the two images with binocular stereo parallax described above can be encoded by computer calculation of the required 3D scene depth and rendering the corresponding viewing distance in physical space from the camera's perspective. Alternatively, the parallax portion of the planar image can be segmented and filled using deep learning and manual segmentation to generate a parallax map.

[0074] It should be emphasized that the first emitted light is a collimated light. Collimation can be achieved by illuminating the three-color filter with collimated backlight or by collimating the self-illuminating LED.

[0075] S220, the polarization state of the first outgoing light beam is modulated to obtain the second outgoing light beam;

[0076] It is understandable that, based on the first outgoing ray corresponding to the target image obtained by ray tracing calculation in step 210, the polarization state of the first outgoing ray is further modulated to obtain the second outgoing ray.

[0077] Specifically, the first outgoing light beam is incident on the polarization modulation device with a single-angle polarization state. The polarization modulation device modulates the polarization angle of the first outgoing light beam according to the pre-calculated linear polarization angle, thereby obtaining the second outgoing light beam.

[0078] It should be noted that the polarization angle of the second emitted light obtained by polarization state modulation through a polarization modulation device can be arbitrarily adjusted.

[0079] S230, based on metasurface devices, polarizes and splits the second outgoing light beam to obtain a naked-eye visible binocular stereo image corresponding to the three-dimensional image;

[0080] It is understandable that, based on the polarization state modulation of the first emitted light in step S220 to obtain the second emitted light, further, based on the pre-prepared metasurface device, the second emitted light is polarized and split in the horizontal and vertical directions, and combined with polarization modulation to achieve light intensity modulation, thereby obtaining a naked-eye visible binocular stereo image corresponding to the three-dimensional image.

[0081] Specifically, the metasurface structure of the metasurface device is used to polarize and split the second outgoing light beam. The metasurface structure of the metasurface device uses polarization-dependent rectangular columnar superatoms to generate different phase template modulation effects on the collimated input light with horizontal and vertical polarization states, corresponding to two different lens-like templates, so as to complete the directional polarization and splitting of the collimated light beam to the binoculars.

[0082] Polarization beam splitting includes horizontal and vertical polarization beam splitting. According to the working characteristics of the metasurface polarization beam splitter, the horizontally upward polarization beam component will be split to the left eye, while the vertically upward polarization beam component will be split to the right eye. The specific splitting angle depends on the distance and the binocular interpupillary distance. Thus, by using the two orthogonal polarization states of the second outgoing light to correspond to the directions of the two outgoing light rays, different light intensities V1 and V2 in two directions in space can be generated, realizing binocular parallax and achieving the effect of stereoscopic vision.

[0083] In this embodiment, based on the 3D image corresponding to the stereoscopic image to be displayed, a target image is obtained through ray tracing calculation. A first emitted ray is determined based on the target image, and the first emitted ray is further polarized to obtain a second emitted ray. Then, the second emitted ray is polarized and split using a metasurface device to obtain a naked-eye visible stereoscopic image corresponding to the 3D image. This method, based on the polarization beam splitting function of the metasurface device, can split a collimated planar light source into directional rays with twice the information, generating binocular parallax. Compared to traditional binocular stereoscopic display technology, this method does not lose planar resolution, and the system has the advantages of small size, light weight, stable structure, and no need for viewers to wear additional devices, achieving 3D display with naked-eye binocular stereoscopic parallax.

[0084] Based on the above embodiments, the fabrication steps of the above metasurface device specifically include: calculating the required light divergence angle and deflection angle according to the relative positions of the light source sub-pixel and the observer's binoculars; determining a first phase modulation template and a second phase modulation template based on the light divergence angle and deflection angle, wherein the first phase modulation template is used to directionally refract the horizontal polarization component of the second emitted light to the first region, and the second phase modulation template is used to directionally refract the vertical polarization component of the second emitted light to the second region; arranging the given first and second phase modulation templates according to a pre-constructed meta-atom database with the meta-atom size as the pixel size to obtain the metasurface structure of the entire display area, wherein the first phase modulation template is used to perform horizontal polarization beam splitting of the second emitted light, and the second phase modulation template is used to perform vertical polarization beam splitting of the second emitted light; and fabricating the metasurface device by electron beam exposure or photolithography combined with reactive ion etching based on the metasurface structure.

[0085] Specifically, firstly, a superatomic database is constructed, and a series of superatomic structures of different sizes are designed. The superatomic structures of different sizes have different near-field phase modulations on the second outgoing light.

[0086] In one specific embodiment, the superatomic structure is a rectangular pillar superatomic structure, and the material is silicon nitride.

[0087] In practical design processes, the Finite-Difference Time-Domain (FDTD) method can be used to simulate the horizontal and vertical polarization responses of superatoms of different sizes to obtain richer data. Specifically, FDTD is used to calculate the phase modulation and transmittance of superatoms of different sizes; by adjusting the parameters, a series of results are obtained with the same period and height, high transmittance (e.g., greater than 0.7), and phase modulation covering [0, 2π]. 2 The superatomic data is used to obtain a pre-constructed superatomic database.

[0088] Secondly, based on the target viewing point area of ​​binocular stereo vision in space, the polarization angle range of the metasurface device for polarizing and splitting the second emitted light beam, and the luminous intensity range for modulating the light intensity of the second emitted light beam are calculated.

[0089] It should be noted that the prepared metasurface device can always modulate the polarization angle of the second emitted light to a certain polarization angle range. Combined with polarization modulation at any angle, it can also modulate the emitted light intensity of the left and right eye channels to a certain light intensity range.

[0090] In one specific embodiment, the aforementioned target viewing viewpoint area is the optimal viewing viewpoint area.

[0091] Furthermore, based on the relative positions of the light source sub-pixels and the observer's binoculars, the required light divergence angle and deflection angle are calculated, and based on the light divergence angle and deflection angle, the first phase modulation template and the second phase modulation template are determined.

[0092] It should be noted that the first phase modulation template is used to refract the horizontal polarization component of the second outgoing light into the first region, and the second phase modulation template is used to refract the vertical polarization component of the second outgoing light into the second region. The first and second regions are the observer's binocular regions, namely the left eye region and the right eye region.

[0093] In detail, in one specific embodiment, the first phase modulation template is used to orient the horizontal polarization component of the second emitted light to the observer's left eye region, and the second phase modulation template is used to orient the vertical polarization component of the second emitted light to the observer's right eye region.

[0094] In another specific embodiment, the first phase modulation template is used to orient the horizontal polarization component of the second outgoing light to the observer's right eye region, and the second phase modulation template is used to orient the vertical polarization component of the second outgoing light to the observer's left eye region.

[0095] It should also be noted that the first phase modulation template and the second phase modulation template mentioned above adopt the form of a lens superimposed blazed grating, and their specific expressions are as follows:

[0096]

[0097] in, As the first phase modulation template, As the second phase modulation template, f x,HH and f x,VV All are horizontal lens focal lengths, f y,HH and f y,VV All are vertical lens focal lengths, θ x,HH and θ x,VV All are horizontal deflection angles, θ y,HH and θ y,VV All are vertical deflection angles, x and y are spatial coordinates, and k is the wave vector of the plane wave.

[0098] The first and second phase modulation templates mentioned above can perform polarization beam splitting. Corresponding to the collimation characteristics of the beams emitted from the left and right eye channels, they can be designed by changing the focal length, and the deflection angle can also be freely designed.

[0099] In order to enable the beams emitted from the left and right eye channels to be projected onto the binocular region respectively, the required divergence angle and deflection angle can be roughly estimated based on the distance between the binoculars and the binocular stereo image, as well as the interpupillary distance, and then the first phase modulation template and the second phase modulation template used in the metasurface device can be obtained.

[0100] Furthermore, based on pre-constructed superatoms, with the superatom size as the pixel size, they are arranged according to the first phase modulation template and the second phase modulation template respectively to obtain the metasurface structure of the entire display area.

[0101] Based on a pre-built superatomic database, with the superatomic size as the pixel size, metasurfaces with phase distributions as close as possible to the first and second phase modulation templates are arranged. This allows us to obtain the metasurface structure corresponding to a single light source sub-pixel. By applying the same steps to all light source sub-pixels, we can obtain the metasurface structure corresponding to the entire display area.

[0102] Finally, based on the metasurface structure, metasurface devices are fabricated through electron beam lithography or photolithography combined with reactive ion etching. Specifically, Figure 3 and Figure 4 Two schematic diagrams of the metasurface structure of the metasurface device provided by the present invention are shown respectively.

[0103] In one embodiment, the simulation is performed using the finite-difference time-domain method combined with physical optical propagation, taking the far-field light intensity at 200 mm as an example. Figure 5 One of the polarization beam splitting schematic diagrams of metasurface polarization beam splitting modulation provided by the present invention is shown.

[0104] Figure 5 The relevant simulation parameters include: beam wavelength of 0.63000 μm, medium refractive index of 1.00000@0.0000 (degrees), display X width = 5.3707E+02 mm, Y height = 5.3707E+02 mm, and peak irradiance = 1.4019E-07 watts / mm². 2 Total power = 1.4734E-04 watts, Pilot: size = 2.3316E+00, beam waist = 1.7202E-02, position = 2.0000E+02, Rayleigh length = 1.4755E+00, beam width X = 1.33435E+02, Y = 2.07082E+02 mm.

[0105] Figure 6 The second schematic diagram of polarization beam splitting modulation of metasurface provided by the present invention is shown. Figure 6The relevant simulation parameters include: beam wavelength of 0.63000 μm, medium refractive index of 1.00000@0.0000 (degrees), display X width = 5.3707E+02 mm, Y height = 5.3707E+02 mm, and peak irradiance = 6.2854E-08 watts / mm². 2 Total power = 1.1521E-04 watts, Pilot: size = 2.3286E+00, beam waist = 1.7224E-02, position = 2.0000E+02, Rayleigh length = 1.4794E+00, beam width X = 1.59422E+02, Y = 1.62047E+02 mm.

[0106] The simulation results show that, under the two different polarization conditions, the divergence angle and deflection angle are consistent with expectations, and the binocular regions can be projected separately.

[0107] In this embodiment, the required light divergence angle and deflection angle are calculated based on the relative positions of the light source subpixels and the observer's binocular vision. Based on the light divergence angle and deflection angle, the first phase modulation template and the second phase modulation template are determined. Then, based on the pre-constructed meta-atom database, with the super-atom size as the pixel size, the super-atoms are arranged according to the first and second phase modulation templates respectively to obtain the metasurface structure of the entire display area. Based on the metasurface structure, the metasurface is prepared by electron beam exposure or photolithography combined with reactive ion etching to obtain a metasurface device. Then, the second emitted light is polarized and split based on the metasurface device to obtain a naked-eye visible binocular stereo image corresponding to the three-dimensional image. This method can achieve three-dimensional display with naked-eye binocular stereo parallax without loss of planar resolution, and the system has the advantages of small size, light weight, stable structure, and no need for the viewer to wear additional equipment.

[0108] Based on the above embodiments, the first emitted light is further subjected to polarization state modulation, including: determining the linear polarization angle by means of a polarization state calculation formula, wherein the polarization state is determined based on the emitted light intensity of the left eye channel and the emitted light intensity of the right eye channel; and performing polarization state modulation on the first emitted light according to the determined linear polarization angle.

[0109] It is understandable that for a single sub-pixel of a light source device, the emitted light is monochromatic and linearly polarized with a single polarization angle, and its intensity can be arbitrarily adjusted, denoted as I. After passing through the polarization modulation device, the linear polarization angle of the second emitted light incident on the metasurface device can also be arbitrarily adjusted, denoted as β.

[0110] After passing through the metasurface device, according to the working characteristics of the metasurface polarization beam splitter, the horizontally polarized component will be split to the left eye, and the vertically polarized component will be split to the right eye. The output light intensity of the left eye channel and the output light intensity of the right eye channel are expressed as follows:

[0111] I H =I cos 2 βθ

[0112] I V =I sin 2 β

[0113] In actual display, the light intensity emitted from the left eye channel and the light intensity emitted from the right eye of each sub-pixel of the light source are arbitrarily given, which is why two different images can be displayed on the left and right.

[0114] The light intensity I emitted through the given left eye channel H And the light intensity emitted from the right eye I V Based on the aforementioned relational expression, the luminous intensity I and linear polarization angle β of the first emitted light that needs to be loaded onto the sub-pixel of the light source can be deduced.

[0115] Specifically, the luminous intensity I of the first emitted ray is calculated using the following formula:

[0116]

[0117] Where I is the luminous intensity of the first emitted ray, I H The intensity of light emitted from the left eye channel, I V The intensity of light emitted from the right eye channel.

[0118] The formula for calculating the polarization state to determine the linear polarization angle is as follows:

[0119]

[0120] Where β is the linear polarization angle, I H The intensity of light emitted from the left eye channel, I V The intensity of light emitted from the right eye channel.

[0121] By analogy, the required luminous intensity and polarization state for each sub-pixel of the light source can be obtained, thereby realizing the display.

[0122] It can be understood that the computer processes two images encoded with binocular stereo parallax, which correspond to the light intensities split into the left and right eye regions respectively. Combining the linear superposition principle of the metasurface polarization beam splitter, the required light source subpixel emission intensity I and the linear polarization angle β of the polarization modulation device can be deduced. By loading appropriate I and β onto each light source subpixel, two complete images can be obtained, thus realizing the three-dimensional display of binocular stereo parallax.

[0123] In this embodiment, based on the three-dimensional image corresponding to the stereoscopic image to be displayed, according to the polarization beam splitting and intensity modulation rules of the second emitted light by the metasurface structure of the metasurface device, the computer is used to perform reverse calculation of the stereoscopic image to be displayed, to obtain the sub-pixel emission intensity of each light source and the linear polarization angle of the polarization modulation device, thereby obtaining two complete images corresponding to the stereoscopic region, and thus realizing the three-dimensional display of stereoscopic parallax.

[0124] Figure 7 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 7 As shown, the electronic device may include a processor 710, a communication interface 720, a memory 730, and a communication bus 740, wherein the processor 710, the communication interface 720, and the memory 730 communicate with each other through the communication bus 740. The processor 710 can call logic instructions in the memory 730 to execute a naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting modulation. The method includes: obtaining a target image by ray tracing calculation based on a three-dimensional image, and determining a first outgoing ray based on the target image, wherein the target image is two images encoded with binocular stereoscopic parallax, and the first outgoing ray is a collimated ray; performing polarization state modulation on the first outgoing ray to obtain a second outgoing ray; and performing polarization beam splitting on the second outgoing ray based on a metasurface device to obtain a naked-eye visible binocular stereoscopic image corresponding to the three-dimensional image.

[0125] Furthermore, the logical instructions in the aforementioned memory 730 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.

[0126] On the other hand, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting modulation provided by the above methods. The method includes: obtaining a target image by ray tracing calculation based on a three-dimensional image, and determining a first outgoing ray based on the target image. The target image is two images encoded with binocular stereoscopic parallax, and the first outgoing ray is a collimated ray; performing polarization state modulation on the first outgoing ray to obtain a second outgoing ray; and performing polarization beam splitting on the second outgoing ray based on a metasurface device to obtain a naked-eye visible binocular stereoscopic image corresponding to the three-dimensional image.

[0127] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, 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 any creative effort.

[0128] 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.

[0129] 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 naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation, characterized in that, include: A light source device is used to obtain a target image by ray tracing calculation based on a three-dimensional image, and to determine the first outgoing ray of the three-dimensional image based on the target image, wherein the target image is two images encoded with binocular stereo parallax; A polarization modulation device is used to modulate the polarization state of the first emitted light to obtain a second emitted light; the polarization state of the second emitted light determines the light intensity ratio of the left and right eye channels after polarization beam splitting. A metasurface device is used to polarize and split the second emitted light beam, refracting the horizontal polarization component of the second emitted light beam into a first region and refracting the vertical polarization component of the second emitted light beam into a second region, thereby obtaining a naked-eye visible binocular stereoscopic image corresponding to the three-dimensional image. The light source device, the polarization modulation device, and the metasurface device are arranged sequentially in the optical path of the first emitted light. The first emitted light is a collimated light. The metasurface device is prepared based on superatoms and a phase modulation template through electron beam exposure and reactive ion etching.

2. The naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation 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 the preset number of metasurface modulation units; Each of the light source sub-pixels corresponds one-to-one with each of the metasurface modulation units.

3. The naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation according to claim 1, characterized in that, The metasurface device corresponds to a first phase modulation template and a second phase modulation template. The first phase modulation template is used to refract the horizontal polarization component of the second emitted light into a first region, and the second phase modulation template is used to refract the vertical polarization component of the second emitted light into a second region.

4. The naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation according to claim 1, characterized in that, The metasurface device is made of silicon nitride or silicon dioxide.

5. The naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation according to claim 1, characterized in that, The light source device is used to generate collimated light by illuminating a three-color filter with collimated backlight or by collimating an LED to emit its own light.

6. A method for naked-eye binocular stereoscopic display based on metasurface polarization beam splitting modulation, based on the naked-eye binocular stereoscopic display system based on metasurface polarization beam splitting modulation as described in any one of claims 1-5, characterized in that, include: Based on the 3D image, a target image is obtained through ray tracing calculation, and a first outgoing ray is determined based on the target image. The target image consists of two images encoded with binocular stereo parallax, and the first outgoing ray is a collimated ray. The first outgoing light beam is polarized to obtain the second outgoing light beam; The second emitted light is polarized and split using a metasurface device to obtain a naked-eye visible binocular stereo image corresponding to the three-dimensional image.

7. The naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting modulation according to claim 6, characterized in that, The specific steps for fabricating the metasurface device include: Calculate the required light divergence angle and deflection angle based on the relative positions of the light source sub-pixels and the observer's binoculars; Based on the light divergence angle and deflection angle, a first phase modulation template and a second phase modulation template are determined. The first phase modulation template is used to orient the horizontal polarization component of the second emitted light to the first region, and the second phase modulation template is used to orient the vertical polarization component of the second emitted light to the second region. Based on a pre-built superatomic database, the superatomic size is used as the pixel size, and the superatomic structures are arranged according to the first phase modulation template and the second phase modulation template respectively to obtain the metasurface structure of the entire display area. Based on the metasurface structure, the metasurface is prepared by electron beam lithography or photolithography combined with reactive ion etching to obtain the metasurface device.

8. The naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting modulation according to claim 7, characterized in that, The step of obtaining a target image through ray tracing calculation based on a 3D image and determining a first outgoing ray based on the target image includes: Based on the ray divergence angle and deflection angle, the target image is obtained by ray tracing calculation. The target image includes a left-eye channel plane image corresponding to the observer's left eye and a right-eye channel plane image corresponding to the observer's right eye. The intensity of the first emitted light ray is calculated based on the light intensity emitted from the left eye channel corresponding to the left eye channel planar image and the light intensity emitted from the right eye channel corresponding to the right eye channel planar image.

9. The naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting modulation according to claim 7, characterized in that, The polarization beam splitting and intensity modulation of the second emitted light includes: Based on the metasurface structure of the metasurface device, the second emitted light is collimated and directionally projected into the binocular region to complete the polarization and beam splitting of the second emitted light.

10. The naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting modulation according to claim 6, characterized in that, The polarization state modulation of the first emitted light includes: The linear polarization angle is determined using the polarization state calculation formula; The first emitted light is polarized according to the determined linear polarization angle.

11. The naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting modulation according to claim 10, characterized in that, The formula for calculating the polarization state is as follows: Where β is the linear polarization angle, I H I represents the light intensity emitted from the left eye channel. V The intensity of light emitted from the right eye channel.

12. The naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting modulation according to claim 8, characterized in that, The step of calculating the intensity of the first emitted ray based on the emitted light intensity of the left eye channel corresponding to the left eye channel planar image and the emitted light intensity of the right eye channel corresponding to the right eye channel planar image includes: The light intensity of the first emitted ray is determined according to a preset formula, which is as follows: Where I is the intensity of the first emitted ray, I H I represents the light intensity emitted from the left eye channel. V The intensity of light emitted from the right eye channel.

13. 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 steps of the naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting modulation as described in any one of claims 6 to 12.

14. 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 steps of the naked-eye binocular stereoscopic display method based on metasurface polarization beam splitting modulation as described in any one of claims 6 to 12.

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