DOE element design method and system, and three-dimensional display

Abstract

The invention relates to a DOE element design method and system and a three-dimensional display, and the method comprises the steps: S1, carrying out the phase recovery of phases passing through different wavelengths of a DOE element in the three-dimensional display, and obtaining a DOE phase diagram; s2, global optimization is carried out on the DOE phase diagram, and a globally optimized DOE phase diagram is obtained; and S3, designing a DOE element according to the globally optimized DOE phase diagram. According to the invention, the DOE element can be effectively designed, so that the light field information of the light beam passing through the DOE element can be effectively adjusted.

Description

Technical Field

[0001] The present invention relates to the technical field of three-dimensional display design, and in particular to a DOE element design method, system and three-dimensional display. Background Art

[0002] In recent years, 3D display technology has gained widespread attention and application in various fields, particularly in virtual reality, augmented reality, medical imaging, education and training, and the entertainment industry. 3D display technologies, including volumetric 3D display, light field 3D display, and holographic 3D display, can provide more realistic visual effects than traditional 2D displays. Among them, light field 3D display has significant market potential.

[0003] Existing light field 3D displays typically consist of a light modulator and a 2D display screen. The 2D display screen presents a synthetic parallax image, which is then propagated to different viewing angles in space via the light modulator, thereby achieving a 3D effect. Therefore, the total information content of the 3D display is determined by the spatial bandwidth product (SBP) of the 2D display screen. Light modulators used in existing technologies include cylindrical lens gratings, diffraction gratings, and liquid crystal lenses. However, these do not change the overall information content, which is still limited by the total resolution of the display panel.

[0004] The display panels used in existing light field 3D displays are mostly liquid crystal display panels (LCDs). LCD panels use color filters to modulate the three RGB wavelengths to achieve color display. In other words, three RGB sub-pixels constitute one image pixel. Therefore, the information utilization rate of existing LCD panels is not high. On the other hand, the key performance indicators of light field 3D displays include angular resolution, spatial resolution, and field of view. However, due to the limited spatial bandwidth product of LCD panels, the key performance indicators of light field 3D displays currently conflict with each other, resulting in a less realistic visual experience.

[0005] In summary, existing 3D displays based on liquid crystal display panels (LCDs) are not realistic and have poor 3D display effects, thereby reducing the user's visual experience of 3D displays. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the problem in the prior art that 3D display based on liquid crystal display panels (LCDs) is not realistic and has poor 3D display effects, thereby reducing the user's visual experience of 3D display.

[0007] To solve the above technical problems, the present invention provides a DOE element design method, comprising:

[0008] Step S1: performing phase recovery on the phases of different wavelengths passing through the DOE element in the three-dimensional display to obtain a DOE phase map;

[0009] Step S2: performing global optimization on the DOE phase diagram to obtain a globally optimized DOE phase diagram;

[0010] Step S3: Designing DOE elements according to the globally optimized DOE phase diagram.

[0011] In one embodiment of the present invention, in step S1, phase recovery is performed on the phases of different wavelengths passing through the DOE element in the three-dimensional display to obtain a DOE phase map, and the formula is:

[0012]

[0013] Where φ is the DOE phase diagram, arg[] is the complex phase angle, λ1 = 610 nm, λ2 = 530 nm, and λ3 = 450 nm represent the emission wavelengths of the field sequential LCD of the 3D display, and α is the weighting factor. are the phases of n×n pixels in the field sequential LCD of the three-dimensional display under red, green and blue wavelengths, respectively, and u and v represent the discrete pixel coordinates on the DOE element.

[0014] In one embodiment of the present invention, the method for globally optimizing the DOE phase diagram in step S2 is:

[0015] The DOE phase diagram is globally optimized by the particle swarm optimization algorithm, and the fitness function used by the particle swarm optimization algorithm is:

[0016] F=β1×G(λ1)+β2×G(λ2)+β3×G(λ3);

[0017]

[0018] in, is the energy utilization rate of the i-th wavelength, is the illumination uniformity of the i-th wavelength, is the structural similarity index of the i-th wavelength, β1, β2, and β3 are the weights of the fitness values of the three wavelengths, w1, w2, and w3 are the weights of each indicator, G(λ i ) is the i-th wavelength λ i The fitness function of , F is the total fitness function.

[0019] In one embodiment of the present invention, when designing the DOE element (3), step S3 further includes: when the light source passes through the DOE element (3), the angular spacing between adjacent viewpoints satisfies the formula:

[0020]

[0021] Where Δθ is the angular distance between adjacent viewpoints, d is the physical distance between human pupils, and f is the set distance from the observer to the display.

[0022] In one embodiment of the present invention, the viewing angle of the three-dimensional display satisfies:

[0023] FOV=N*Δθ

[0024] Where FOV is the field of view, Δθ is the angular spacing between adjacent viewpoints, and N is the number of viewpoints;

[0025] Assuming that the total number of pixels of the 3D display is a constant value and is set to S×P, the spatial resolution R and the number of viewpoints N are mutually constrained, expressed as:

[0026]

[0027] In one embodiment of the present invention, when designing the DOE element (3), step S3 further includes: adjusting the display distance f′ and the spacing d′ of the target viewpoint light field, as shown in the formula:

[0028]

[0029] The display distance f′ needs to be adjusted to be smaller than the set distance f between the observer and the 3D display, and Δθ is the angular distance between adjacent viewpoints.

[0030] To solve the above technical problems, the present invention provides a DOE element design system, comprising:

[0031] Phase recovery module: used to recover the phase of different wavelengths passing through the DOE element in the 3D display to obtain the DOE phase map;

[0032] Global optimization module: used for performing global optimization on the DOE phase diagram to obtain a globally optimized DOE phase diagram;

[0033] Design module: used for designing DOE elements according to the globally optimized DOE phase diagram.

[0034] To solve the above technical problems, the present invention provides a three-dimensional display, comprising a field-sequential LCD, a Fresnel lens, and a DOE element arranged in sequence, wherein the field-sequential LCD is used to provide initial light field information, the Fresnel lens is used to collimate and focus the initial light field information, and the DOE element is used to perform three-dimensional reconstruction of the collimated and focused initial light field information to present a three-dimensional display effect.

[0035] To solve the above technical problems, the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned DOE element design method when executing the computer program.

[0036] To solve the above technical problems, the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the above-mentioned DOE element design method are implemented.

[0037] The above technical solution of the present invention has the following advantages over the prior art:

[0038] The DOE element design method of the present invention re-optimizes the DOE phase diagram and reconstructs the fitness function of the particle swarm optimization algorithm during the optimization process, so that the particle swarm optimization algorithm can find the optimal solution as quickly as possible. The DOE element is designed based on the optimized DOE phase diagram. In order to achieve a better display effect of the final three-dimensional display, the angular spacing between the light source and the adjacent viewpoints after passing through the DOE element and the field of view of the three-dimensional display are designed, and finally the DOE element is applied to the three-dimensional display.

[0039] The three-dimensional display constructed by the present invention is a new type of display that switches red, green, and blue primary color sub-field images at a high refresh rate to achieve color mixing. The field sequential LCD does not require color filters, but instead achieves color mixing through the principle of time multiplexing. This allows the spatial bandwidth product of the field sequential LCD to be tripled under the same process parameters.

[0040] The present invention aligns and bonds each structural pixel of a pixelated multi-wavelength DOE element with an image pixel of a field-sequential LCD one by one (a Fresnel lens is also provided between the DOE element and the field-sequential LCD), thereby obtaining a wavelength-multiplexed 3D display device. The three-dimensional display of the present invention can be applied in scenarios such as VR, AR, projectors, and vehicle-mounted HUD displays. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0042] Figure 1 is a flow chart of the method of the present invention;

[0043] Figure 2 1 is a display principle diagram of a three-dimensional display based on a field sequential LCD and DOE elements in an embodiment of the present invention;

[0044] Figure 312 DOE phase distribution diagrams corresponding to the 12 viewpoints in the embodiment of the present invention;

[0045] Figure 4 4 is a system diagram of a three-dimensional display according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0047] Example 1

[0048] Reference Figure 1 The present invention relates to a DOE element design method, comprising:

[0049] Step S1: performing phase recovery on the phases of different wavelengths passing through the DOE element 2 (Diffractive Optical Element) to be designed in the three-dimensional display to obtain a DOE phase map;

[0050] Step S2: performing global optimization on the DOE phase diagram to obtain a globally optimized DOE phase diagram;

[0051] Step S3: Designing the DOE element 2 according to the globally optimized DOE phase diagram.

[0052] The following is a detailed introduction to this embodiment:

[0053] The core of this embodiment is to construct a new three-dimensional display (combining field sequential LCD1 with DOE element 2). Field sequential LCD1 (using field sequential display technology) is a display that switches red, green, and blue primary color sub-field images at high frequency, and achieves color mixing through time multiplexing without the need for color filters. Compared with traditional displays, field sequential display significantly improves the spatial bandwidth product of the display device, so that under the same process conditions, the display resolution is multiplied, and the contradiction between spatial resolution and field of view is alleviated. This application also designs DOE element 2 and designs it into a pixelated multi-wavelength DOE element 2. The specific method of constructing the wavelength multiplexed DOE element 2 is as follows:

[0054] In order to obtain the ability of color display, DOE elements 2 based on different wavelengths are constructed: first, the Gerchberg-Saxton (GS) algorithm is used for phase recovery, and the optimal DOE phase (DOE phase diagram) is obtained through multiple iterative calculations.

[0055] See also Figure 2 and Figure 4 , Figure 2A three-dimensional display is constructed by combining a field sequential LCD 1 and a DOE element 2, and a Fresnel lens 3 is provided between the field sequential LCD 1 and the DOE element 2. Figure 2 and Figure 4 The figure also includes a person's binoculars 105. Specifically, the field sequential LCD 1 is used to provide initial light field information, the Fresnel lens 3 is used to collimate and focus the initial light field information, and the DOE element 2 is used to perform three-dimensional reconstruction on the collimated and focused initial light field information to present a three-dimensional display effect. Figure 3 12 viewpoints 5 are shown, corresponding to 12 DOE phase diagrams. Figure 3 Specifically, it is divided into two layers, and both the upper and lower layers include 6 viewpoints5.

[0056] Before performing phase recovery on DOE element 2, perform initialization:

[0057] (1) Determining the initial conditions for three-dimensional display, wherein the initial conditions include the resolution of the display content, the number of viewpoints, the viewpoint spacing, and the characteristic parameters of the display; the resolution of the display content includes the size of the image, the light intensity of each pixel, color information, and the viewing angle range; the viewpoint information includes the position of the observer and the observation angle; the characteristic parameters of the display include the pixel arrangement of the display, optical transmittance, and display frequency, etc.

[0058] (2) Constructing a computational grid and performing pixelation processing;

[0059] The computational grid is used to represent the light field in three-dimensional space. Pixelation processing refers to decomposing the light field into discrete optical elements, each element corresponding to a pixel, and modeling is performed using the spatial position and optical properties of each pixel.

[0060] After the initialization process, the method for recovering the phase of different wavelengths passing through the DOE element 2 in the three-dimensional display in step S1 includes: phase optimization using wavelength multiplexing: by utilizing light of different wavelengths, wavelength multiplexing control can be performed on a phase plane, and the phase recovery formula is:

[0061]

[0062] Where φ is the DOE phase diagram, arg[] is the complex phase angle, λ1 = 610 nm, λ2 = 530 nm, and λ3 = 450 nm represent the emission wavelengths of the field sequential LCD of the 3D display, and α is the weighting factor. where u and v represent the phases of an n×n pixel in a field-sequential LCD for a 3D display at red, green, and blue wavelengths, respectively. This formula allows for the manipulation of multiple wavelengths of light within the same diffractive optical element, generating a target viewpoint light field at the same display distance of 500 mm.

[0063] Furthermore, the method for globally optimizing the DOE phase diagram in step S2 is:

[0064] The particle swarm optimization (PSO) algorithm is used to globally optimize the phase of DOE element 2 to ensure that the light propagation effect at different wavelengths is maximized, thereby improving the display brightness and contrast. The fitness function used by the particle swarm optimization algorithm is:

[0065] F=β1×G(λ1)+β2×G(λ2)+β3×G(λ3);

[0066]

[0067] in, is the energy utilization rate of the i-th wavelength, is the illumination uniformity of the i-th wavelength, is the structural similarity index of the i-th wavelength, β1, β2, and β3 are the weights of the fitness values of the three wavelengths, w1, w2, and w3 are the weights of each indicator, G(λ i ) is the i-th wavelength λ i The fitness function of , F is the total fitness function.

[0068] In this embodiment, the DOE element 2 under three wavelengths is optimized by using a combined method of the Gerchberg-Saxton (GS) algorithm and the particle swarm optimization (PSO) algorithm, so as to ensure that light of each wavelength can correctly form the desired three-dimensional effect in the display space.

[0069] Furthermore, when designing the DOE element 2, step S3 further includes: when the light source passes through the DOE element 2 and reaches the adjacent viewpoint 5, the angular spacing satisfies the formula:

[0070]

[0071] Where Δθ is the angular distance between adjacent viewpoints, d is the physical distance between human pupils, and f is the set distance from the observer to the 3D display.

[0072] Furthermore, the viewing angle of the three-dimensional display satisfies:

[0073] FOV=N*Δθ

[0074] Where FOV is the field of view, Δθ is the angular spacing between adjacent viewpoints, and N is the number of viewpoints.

[0075] In this embodiment, it is assumed that the total number of pixels of the 3D display is constant, namely S×P (for example, the number of pixels of a 1080P screen is 1920×1080). Then the spatial resolution R can be expressed as:

[0076]

[0077] That is, when the total number of pixels is constant, the spatial resolution R and the number of viewpoints N are mutually constrained.

[0078] When designing the DOE element 2, step S3 also includes: adjusting the display distance f' and the spacing d' of the target viewpoint light field, the formula is:

[0079]

[0080] The display distance f′ needs to be adjusted to be smaller than the set distance f between the observer and the 3D display, and Δθ is the angular distance between adjacent viewpoints.

[0081] Step S4: obtaining light field information of each pixel based on the optimized DOE element 2;

[0082] For each pixel, the optimized DOE element 2 acquires the light intensity, color information, and viewing angle range at that location, and superimposes this information to form the light field information corresponding to each viewpoint 5. This step requires considering the propagation paths and diffraction effects of light of different wavelengths in three-dimensional space.

[0083] Step S5: Using the field-sequential LCD1 as a light source, the calculated light field information is used to generate a 3D display effect. The field-sequential LCD1 converts the diffracted light field information of each pixel into a visible light signal by adjusting the light source output frame by frame, ensuring that the corresponding 3D effect is displayed at different viewing angles. The specific steps are:

[0084] (1) Encoding the light intensity and phase information of each pixel calculated in step S4 into a light source signal;

[0085] (2) The light source of the field sequential LCD 1 outputs different light field information, and the display content is updated in real time according to the difference between the display content and the observer's viewpoint.

[0086] Step S6: Divide the time step and update the light field information of the display content in each time step;

[0087] The entire display time is divided into multiple time steps, each of which corresponds to a light source update. Within each time step, the light field propagation of different wavelengths is calculated and the display state of each pixel is updated.

[0088] Step S7: Optimizing the computational grid within each display cycle using dynamic grid reconstruction technology;

[0089] For each time step, the node positions of the computational grid are dynamically adjusted based on the current light field distribution information, making the calculation results more accurate. The PSO algorithm is used to optimize the grid structure to ensure the optimal display effect of each pixel.

[0090] Step S8: Outputting the final three-dimensional display effect through the field sequential LCD1 according to the result of dynamic grid reconstruction;

[0091] In this step, the calculation results are output through the light source system of the field sequential LCD1 by refreshing frame by frame, and the display information is updated in real time according to the display content and the observer's viewpoint.

[0092] The pixelated multi-wavelength DOE element 2 in this embodiment uses the diffraction effect to control the light source pixel by pixel to achieve fine light field reconstruction. The function of this optical element is to control the three wavelengths of RGB light to obtain the perspective light field at the same position in space; in addition, it can calculate the multiple perspective light fields separately. It can generate a horizontally arranged array of viewpoints 5 in space, such as Figure 2 and Figure 4 As shown, the DOE element 2 is laminated pixel by pixel with the field sequential LCD 1 (with a Fresnel lens 3 between them) to obtain a wavelength multiplexing type naked eye 3D display.

[0093] Example 2

[0094] This embodiment provides a DOE component design system, including:

[0095] Phase recovery module: used to recover the phase of different wavelengths passing through the DOE element in the 3D display to obtain the DOE phase map;

[0096] Global optimization module: used for performing global optimization on the DOE phase diagram to obtain a globally optimized DOE phase diagram;

[0097] Design module: used for designing DOE elements according to the globally optimized DOE phase diagram.

[0098] Example 3

[0099] This embodiment provides a 3D display comprising a field-sequential LCD, a Fresnel lens 3, and a DOE element, arranged in sequence. The field-sequential LCD provides initial light field information, the Fresnel lens 3 collimates and focuses the initial light field information, and the DOE reconstructs the collimated and focused initial light field information into three dimensions, resulting in a 3D display effect. Thanks to the precise control of the pixelated design and overall system optimization, this 3D display achieves realistic 3D display effects while maintaining a compact structure, making it suitable for applications in fields such as naked-eye 3D display, virtual reality, and augmented reality.

[0100] Example 3

[0101] This embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the DOE element design method described in the first embodiment are implemented.

[0102] Example 4

[0103] This embodiment provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the DOE element design method described in the first embodiment are implemented.

[0104] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiment of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal translation scripting language JavaScript, etc.

[0105] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0106] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0107] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0108] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0109] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A DOE element design method, characterized by: include: Step S1: performing phase recovery on the phases of different wavelengths passing through the DOE element in the three-dimensional display to obtain a DOE phase map; Step S2: performing global optimization on the DOE phase diagram to obtain a globally optimized DOE phase diagram; Step S3: Designing DOE elements according to the globally optimized DOE phase diagram.

2. The DOE element design method according to claim 1, wherein: In step S1, the phase of different wavelengths passing through the DOE element in the three-dimensional display is recovered to obtain a DOE phase diagram, which is expressed as follows: Where φ is the DOE phase diagram, arg[] is the complex phase angle, λ1 = 610 nm, λ2 = 530 nm, and λ3 = 450 nm represent the emission wavelengths of the field sequential LCD of the 3D display, and α is the weighting factor. are the phases of n×n pixels in the field sequential LCD of the three-dimensional display under red, green and blue wavelengths, respectively, and u and v represent the discrete pixel coordinates on the DOE element.

3. The DOE element design method according to claim 1, wherein: The method for globally optimizing the DOE phase diagram in step S2 is: The DOE phase diagram is globally optimized by the particle swarm optimization algorithm, and the fitness function used by the particle swarm optimization algorithm is: F=β1×G(λ1)+β2×G(λ2)+β3×G(λ3); in, is the energy utilization rate of the i-th wavelength, is the illumination uniformity of the i-th wavelength, is the structural similarity index of the i-th wavelength, β1, β2, and β3 are the weights of the fitness values of the three wavelengths, w1, w2, and w3 are the weights of each indicator, G(λ i ) is the i-th wavelength λ i The fitness function of , F is the total fitness function.

4. The DOE element design method according to claim 1, wherein: When designing the DOE element, step S3 further includes: when the angular spacing between the light source and the adjacent viewpoints after passing through the DOE element satisfies the formula: Where Δθ is the angular distance between adjacent viewpoints, d is the physical distance between human pupils, and f is the set distance from the observer to the 3D display.

5. The DOE element design method according to claim 1, wherein: The viewing angle of the three-dimensional display satisfies: FOV=N*Δθ Where FOV is the field of view, Δθ is the angular spacing between adjacent viewpoints, and N is the number of viewpoints; Assuming that the total number of pixels of the 3D display is a constant value and is set to S×P, the spatial resolution R and the number of viewpoints N are mutually constrained, expressed as:

6. The DOE element design method according to claim 1, wherein: When designing the DOE element, step S3 further includes: adjusting the display distance f' and the distance d' of the target viewpoint light field, as shown in the formula: The display distance f′ needs to be adjusted to be smaller than the set distance f between the observer and the 3D display, and Δθ is the angular distance between adjacent viewpoints.

7. A DOE component design system, characterized by: include: Phase recovery module: used to recover the phase of different wavelengths passing through the DOE element in the 3D display to obtain the DOE phase map; Global optimization module: used for performing global optimization on the DOE phase diagram to obtain a globally optimized DOE phase diagram; Design module: used for designing DOE elements according to the globally optimized DOE phase diagram.

8. A three-dimensional display, characterized in that: The invention comprises a field sequential LCD, a Fresnel lens and a DOE element arranged in sequence. The field sequential LCD is used to provide initial light field information, the Fresnel lens is used to collimate and focus the initial light field information, and the DOE element is used to perform three-dimensional reconstruction of the collimated and focused initial light field information to present a three-dimensional display effect.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the DOE element design method according to any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the DOE element design method according to any one of claims 1 to 6 are implemented.

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