Method for realizing three-dimensional display by adopting multi-focal-plane display technology

Abstract

The invention discloses a system and method for realizing three-dimensional display by adopting a multi-focal-plane display technology, and the method comprises the steps: building a spherical off-axis system of an image source, a reflector and a free-form mirror, and obtaining an initial structure of the three-dimensional display system; determining an image source mounting position and a human eye observation position, determining an incident light wave of the image source and an emergent light wave after the incident light wave is reflected by the free-form mirror based on the image source mounting position and the human eye observation position, and enabling the emergent light wave to enter the human eye; setting an initialized surface type parameter of the free-form surface mirror, and calculating the influence of the initialized surface type parameter of the free-form surface mirror on the incident light wave to obtain an initial emergent light wave; surface type parameters of the free-form surface mirror are optimized, optimization design is conducted on the surface type parameters of the free-form surface mirror in the three-dimensional display system of the initial structure, and the phase of emergent light waves formed by the free-form surface mirror can exactly correspond to the human eye observation position; through the accurate layout of the free-form mirror, the imaging quality is improved.

Description

Technical Field

[0001] The present invention relates to the field of three-dimensional display technology, and in particular to a method for realizing three-dimensional display by adopting multi-focal plane display technology. Background Art

[0002] Currently, most light field screens include an image generating unit, a window unit and an image magnifying unit, wherein the image generating unit is used to emit image light to the window unit, the window unit reflects the image light from the image generating unit to the image magnifying unit, the image magnifying unit is used to reflect the image light from the window unit to the window unit, and the window unit transmits the image light from the image magnifying unit to the human eye position.

[0003] The above square screen only supports two-dimensional display and cannot present a true three-dimensional light field effect. Its display technology is limited to a two-dimensional plane and lacks comprehensive reconstruction of spatial depth and stereoscopic sense. Therefore, users can only observe images on a predetermined focal plane and cannot achieve dynamic focal length adjustment or a richer three-dimensional visual experience.

[0004] Moreover, most of the light field holographic screens currently on the market use geometric optics methods to perform complex light field reconstruction and calculations, and the imaging quality cannot be accurately determined, and are prone to common optical defects of multi-focal plane displays. Summary of the invention

[0005] The purpose of the present invention is to provide a method for realizing three-dimensional display by using multi-focal plane display technology, so as to solve the technical problems in the prior art that the square screen only supports two-dimensional display, cannot present a true three-dimensional light field effect, and the imaging quality cannot be accurately determined, and is prone to common optical defects of multi-focal plane display.

[0006] In order to solve the above technical problems, the present invention specifically provides the following technical solutions:

[0007] A three-dimensional display system using multi-focal plane display technology, comprising:

[0008] An image source, forming at least two logically separated areas, the image source being used to provide light field data with different depth information;

[0009] A reflector is installed on the opposite side of each separation area of ​​the image source and is distributed off-axis from the installation position of the image source, and the light generated by the image source is reflected by the reflector;

[0010] The free-form surface mirror is distributed off-axis from the installation position of the image source and the reflector, adjusts and reflects the light from the reflector, and through the reflection effect of the free-form surface mirror, the light is respectively converged through the space between the reflectors and guided to the human eye, and finally an image is formed at the target imaging surface.

[0011] As a preferred solution of the present invention, the two separation areas of the image source are distributed in parallel, and absorption walls are provided on both sides of each separation area of ​​the image source, and the absorption walls prevent the light rays generated by two adjacent image sources from intersecting.

[0012] As a preferred solution of the present invention, the reflectors are respectively located on both sides of the free-form surface mirror, and the space between the two reflectors is capable of allowing light reflected by the free-form surface mirror to pass through.

[0013] In addition, the present invention also provides a method for realizing a three-dimensional display system using a multi-focal plane display technology, comprising the following steps:

[0014] Step 100, constructing a spherical off-axis system of an image source, a reflector, and a free-form surface mirror, so that the reflector and the free-form surface mirror are distributed at desired spatial positions, and obtaining an initial structure of a three-dimensional display system;

[0015] Step 200, determining an image source installation position and a human eye observation position, and determining an incident light wave of the image source and an outgoing light wave after the incident light wave is reflected by the free-form surface mirror based on the image source installation position and the human eye observation position, so that the outgoing light wave enters the human eye;

[0016] Step 300, initializing the surface parameters of the free-form surface mirror, setting the initialization surface parameters of the free-form surface mirror, and calculating the influence of the initialization surface parameters of the free-form surface mirror on the incident light wave to obtain the initial outgoing light wave;

[0017] Step 400, optimizing the surface parameters of the free-form surface mirror, optimizing the surface parameters of the free-form surface mirror in the three-dimensional display system of the initial structure, so that the phase of the outgoing light wave formed by the free-form surface mirror can exactly correspond to the observation position of the human eye.

[0018] As a preferred solution of the present invention, in step 400, the method for optimizing the surface parameters of the free-form surface mirror is:

[0019] Step 401, using ray tracing technology to calculate the outgoing light wave after being reflected from the initialized free-form surface mirror, performing Fourier transform on the outgoing light wave, and determining the phase information and amplitude information corresponding to the outgoing light wave when propagating to the target imaging surface;

[0020] Step 402, determining the target light wave phase information corresponding to the target imaging surface, performing an inverse Fourier transform on the target light wave phase information, and determining the target surface parameters of the free-form surface mirror corresponding to the target light wave;

[0021] Step 403, calculating the error coefficient between the target surface parameters of the free-form surface mirror and the initialization surface parameters of the free-form surface mirror, and adjusting its curvature or off-axis parameters by using an optimization strategy so that the phase of the outgoing light is closer to the target light wave phase information;

[0022] Step 404: Use iterative optimization to gradually modify the curved surface shape of the free-form mirror until convergence, so that the phase and amplitude of the incident light wave after the free-form mirror-type reflection can match the required phase distribution.

[0023] As a preferred solution of the present invention, in step 401, the method for determining the phase information and amplitude information corresponding to the outgoing light wave when it propagates to the target imaging surface is:

[0024] Calculate the light field of the incident light wave emitted by the image source after being reflected by the free-form surface mirror:

[0025]

[0026] Among them, U1(x, y) is the complex number of the incident light wave field;

[0027] A1(x,y) is the amplitude of the incident light wave field, which usually depends on the light intensity of the incident light wave;

[0028] Φ1(x,y) is the phase distribution after reflection by the free-form surface mirror;

[0029] Perform Fourier transform on the light field reflected by the free-form surface mirror to calculate the distribution of the incident light field at the target imaging surface:

[0030]

[0031] Among them, U2(u, v) is the light field distribution of the incident light wave at the target imaging surface, including the amplitude A2(u, v) and the phase Φ2(u, v).

[0032] As a preferred solution of the present invention, in step 402, the method for determining the target surface parameters of the free-form surface mirror corresponding to the target light wave is:

[0033] The amplitude of the outgoing light wave after being reflected by the initialized free-form surface mirror at the target imaging surface is kept constant, and the phase distribution of the outgoing light wave is adjusted so that the phase distribution of the outgoing light wave is close to the phase distribution of the target light wave;

[0034] At the target imaging surface, determine the target light wave phase information Φ corresponding to the target imaging surface targert (u, v), the light field of the target light wave at the target imaging plane is specifically:

[0035]

[0036] Among them, U3(u, v) is the complex number of the target light wave field, including amplitude and phase;

[0037] A2(u, v) is the light field amplitude of the incident light wave at the target imaging surface;

[0038] Φ target (u, v) is the target phase information corresponding to the target light wave on the target imaging surface;

[0039] Perform an inverse Fourier transform on the light field of the target light wave at the target imaging surface to determine the light field corresponding to the new free-form surface mirror formed by the target light wave:

[0040]

[0041] Among them, U4(x, y) is the light field corresponding to the new free-form surface mirror formed by the target light wave, and the target mirror reflection phase Φ4(x, y) of the target light wave corresponding to the new free-form surface mirror is determined.

[0042] As a preferred solution of the present invention, in step 403, the method for calculating the error coefficient between the target surface parameters of the free-form surface mirror and the initialization surface parameters of the free-form surface mirror is:

[0043] Calculate the error between the target surface parameters of the free-form surface mirror and the initialization surface parameters of the free-form surface mirror:

[0044] ΔΦ(x,y)=Φ4(x,y)-Φ1(x,y);

[0045] Based on the error between the target surface parameters of the free-form surface mirror and the initialization surface parameters of the free-form surface mirror, the distribution shape of the free-form surface mirror is updated:

[0046] z(x, y)=z(x, y)+α·f(ΔΦ(x, y));

[0047] z(x, y) is the height distribution of the free-form surface mirror;

[0048] α is the growth factor, which is used to control the update rate;

[0049] f(ΔΦ(x, y)) is a mapping function used to adjust the height of the free-form surface mirror, which is usually related to the wavelength of the incident broadcast and the material properties of the free-form surface mirror.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The multi-focal plane three-dimensional display system of the present invention realizes light path control through simple optical design, presents the effect of three-dimensional display, and the system is more direct and simple to implement, avoiding the computational complexity in holographic technology. At the same time, through the precise layout of free-form surface mirrors, common optical defects (such as distortion, spherical aberration, coma and astigmatism, etc.) are reduced, the imaging quality of the display system is improved, and the compactness and space utilization of the system are effectively improved. In addition, the present embodiment can adjust the curved surface shape of the free-form surface mirror according to the movement of the human eye, ensuring that the outgoing light wave reflected by the free-form surface mirror can always reach the human eye. Therefore, the observer can obtain the best visual effect in a specific viewing area, which provides a better user experience compared to the usually fixed viewing area in the light field holographic screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0053] Figure 1 is a schematic diagram of the overall structure of a three-dimensional display system according to an embodiment of the present invention;

[0054] Figure 2 It is a schematic diagram of the overall process of the three-dimensional display method according to an embodiment of the present invention; DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] like Figure 1 As shown, the present invention provides a three-dimensional display system using multi-focal plane display technology, realizes multi-focal plane display effects by designing image sources capable of displaying different depths of field, improves display effects by optimizing optical performance, and solves the shortcomings of traditional display devices in terms of depth of field and two-dimensional plane display. The method of the present invention takes precise optical design as the core, ensuring that the display device realizes accurate focal length display and light field reconstruction during multi-focal plane imaging, thereby improving the overall display clarity and realism.

[0057] The system includes: an image source 1, a reflecting mirror 2 and a free-form mirror 3.

[0058] The image source 1 forms at least two logically separated areas, and the image source 1 is used to provide light field data with different depth information.

[0059] The reflector 2 is installed on the opposite side of each separation area of ​​the image source 1 and is distributed off-axis from the installation position of the image source 1 . The light generated by the image source 1 is reflected by the reflector 2 .

[0060] The free-form surface mirror 3 is installed off-axis with the image source 1 and the reflector 2, and adjusts and reflects the light from the reflector 2. Through the reflection effect of the free-form surface mirror 3, the light is converged through the space between the reflectors 2 and guided to the human eye, and finally an image is formed at the target imaging surface.

[0061] The reflectors 2 are respectively located on both sides of the free-form surface mirror 3 , and the space between the two reflectors 2 is capable of allowing the light reflected by the free-form surface mirror 3 to pass through.

[0062] The system includes key components: R1, R2 (two logically separated areas formed by the image source), Speculum1, Speculum2 (reflector), and free-form mirror.

[0063] The image generation unit for generating dual focal planes is divided into two regions R1 and R2, which respectively display images for two different focal planes. Each image source is responsible for providing light field data with different depth information to achieve a multi-focal plane display effect.

[0064] The two logically separated areas R1 and R2 formed by the image source can emit light containing different focal plane information. These lights first pass through the reflectors Speculum1 and Speculum2, and after multiple reflections, they are accurately guided to the free-form mirror. As the core optical element of the system, the free-form mirror is optimized in design and can accurately adjust and reflect the light from Speculum1 and Speculum2. Through the action of the free-form mirror, these lights are separately converged and guided to the human eye, thereby realizing the reconstruction of the multi-focal plane light field.

[0065] The light from R1 passes through Speculum1 and the free-form surface reflector to a spatial position, while the light from R2 passes through Speculum2 and the free-form surface reflector to a new spatial position, thereby theoretically producing an imaging distance farther than that of R1. In order to fold the light path in a limited space, the light from the R1 and R2 regions passes through two reflectors to form two intermediate images P1 and P2. Ultimately, R1 and R2 project images with different image distances at different object distances. Usually, in a system containing two separate light paths, there will be a certain amount of stray light interference. In order to suppress this phenomenon, an absorption wall is added to the display to isolate the light from the R1 and R2 regions.

[0066] In addition, the two separation areas of the image source 1 are distributed in parallel, and absorption walls are provided on both sides of each separation area of ​​the image source 1. The absorption walls prevent the light generated by two adjacent image sources 1 from intersecting. Therefore, the light emitted from the image generating units R1 and R2 is usually highly collimated, which helps to further suppress stray light.

[0067] The highly free design of the free-form mirror allows for precise control of complex light, ensuring that the light from each focal plane can accurately reach the retina of the human eye, thereby providing a continuous and clear three-dimensional display effect for the observer. This optical path design successfully overcomes the two-dimensional limitations of traditional display technology by integrating the depth information provided by R1 and R2, providing technical support for the three-dimensionalization of display devices.

[0068] At the same time, by reasonably optimizing the positions and angles of Speculum 1, Speculum 2 and free-form surface mirrors, the aberration and energy loss in the optical system are effectively reduced, making the display effect more natural and immersive.

[0069] Therefore, Figure 2 As shown, the present invention also provides a method for realizing a three-dimensional display system using a multi-focal plane display technology, comprising the following steps:

[0070] Step 100: construct a spherical off-axis system of an image source, a reflector, and a free-form surface mirror, so that the reflector and the free-form surface mirror are distributed at desired spatial positions to obtain an initial structure of a three-dimensional display system.

[0071] Step 200: determine the image source installation position and the human eye observation position, and determine the incident light wave of the image source and the outgoing light wave after the incident light wave is reflected by the free-form surface mirror based on the image source installation position and the human eye observation position.

[0072] Step 300, initialize the surface parameters of the free-form surface mirror, set the initialization surface parameters of the free-form surface mirror, and calculate the influence of the initialization surface parameters of the free-form surface mirror on the incident light wave to obtain the initial output light wave, so that the output light wave enters the human eye.

[0073] Step 400, optimizing the surface parameters of the free-form surface mirror, optimizing the surface parameters of the free-form surface mirror in the three-dimensional display system of the initial structure, so that the phase of the outgoing light wave formed by the free-form surface mirror can exactly correspond to the observation position of the human eye.

[0074] It should be noted that the curvature of the free-form mirror controls the refraction and reflection paths of the light. This embodiment can control the propagation direction of the light by precisely adjusting the curvature of the mirror surface, thereby eliminating the spherical aberration, astigmatism and coma caused by the traditional spherical mirror.

[0075] Among them, the surface shape of the free-form surface mirror (i.e., the mirror geometry) is achieved by designing a specific curve of the free-form surface mirror. This embodiment gradually adjusts the surface shape of each point according to the target imaging requirements to achieve the desired light control characteristics, such as focusing the light at the correct position and reducing distortion and coma.

[0076] Since the tilt angle adjustment of the free-form mirror can affect the reflection path of light, especially in off-axis design, by adjusting the tilt angle of the free-form mirror, the distribution of light can be better controlled, and light from different focal planes can pass through the optical system correctly, reducing the distortion and coma of the system;

[0077] The off-axis position setting of the free-form mirror determines its spatial layout in the optical system and affects the reflection effect of light. In this patent, by designing the free-form mirror off-axis, the system can achieve multi-focal plane display while avoiding the optical defects in the traditional axisymmetric system.

[0078] Therefore, this embodiment establishes a spherical off-axis system of the image source, the reflector, and the free-form surface mirror, and designs the shape of the free-form surface mirror, so that all incident light can be focused more accurately and spherical aberration can be eliminated. Similarly, the spherical surface of a traditional free-form surface mirror often produces different focal points in the off-axis area. This embodiment ensures that all light is focused on the same plane by precisely controlling the mirror shape of the free-form surface mirror, thereby reducing coma.

[0079] In step 400, the method for optimizing the surface parameters of the free-form surface mirror is as follows:

[0080] Step 401, using ray tracing technology to calculate the outgoing light wave after being reflected from the initialized free-form surface mirror, performing Fourier transform on the outgoing light wave, and determining the corresponding phase information and amplitude information when the outgoing light wave propagates to the target imaging surface;

[0081] Step 402, determining the target light wave phase information corresponding to the target imaging surface, performing inverse Fourier transform on the target light wave phase information, and determining the target surface parameters of the free-form surface mirror corresponding to the target light wave;

[0082] Step 403, calculating the error coefficient between the target surface parameters of the free-form surface mirror and the initialization surface parameters of the free-form surface mirror, and adjusting its curvature or off-axis parameters by using an optimization strategy so that the phase of the outgoing light is closer to the target light wave phase information;

[0083] Step 404: Use iterative optimization to gradually modify the curved surface shape of the free-form mirror until convergence, so that the phase and amplitude of the incident light wave after the free-form mirror reflection can match the required phase distribution.

[0084] The surface of the free-form mirror after adjustment in this embodiment is not a traditional spherical or flat mirror surface, but a precisely designed aspherical surface. The aspherical shape of the free-form mirror can effectively adjust the propagation path of light so that different light rays can be focused on the same plane, thereby reducing the distortion caused by the geometric asymmetry of the optical system during the imaging process, and can adjust the curvature of different areas so that all light rays can be focused in the same plane, thereby eliminating the influence of astigmatism.

[0085] It should be further explained that the present embodiment can also observe and determine the changes in the user's eye movements and sight lines by optimizing the design of the eye box, and then determine the user's actual viewing needs, limit the phase of the outgoing light wave based on the viewing needs, and further adjust the curved shape of the free-form surface mirror to ensure that the observer can obtain the best visual effect in a specific viewing area. This flexible design provides a better user experience compared to the usually fixed viewing area in the light field holographic screen.

[0086] In step 401, the method for determining the phase information and amplitude information corresponding to the outgoing light wave when it propagates to the target imaging surface is:

[0087] Calculate the light field after the incident light wave emitted by the image source is reflected by the free-form mirror:

[0088]

[0089] Among them, U1(x, y) is the complex number of the incident light wave field;

[0090] A1(x, y) is the amplitude of the incident light wave field, which usually depends on the light intensity of the incident light wave;

[0091] Φ1(x, y) is the phase distribution after reflection by the free-form surface mirror;

[0092] Perform Fourier transform on the light field after reflection by the free-form surface mirror and calculate the distribution of the incident light field at the target imaging surface:

[0093]

[0094] Among them, U2(u, v) is the light field distribution of the incident light wave at the target imaging surface, including the amplitude A2(u, v) and the phase Φ2(u, v).

[0095] In step 402, the method for determining the target surface parameters of the free-form surface mirror corresponding to the target light wave is as follows:

[0096] The amplitude of the outgoing light wave after being reflected by the initialized free-form surface mirror at the target imaging surface is kept constant, and the phase distribution of the outgoing light wave is adjusted so that the phase distribution of the outgoing light wave is close to the phase distribution of the target light wave;

[0097] At the target imaging surface, determine the target light wave phase information Φ corresponding to the target imaging surface target (u, v), the light field of the target light wave at the target imaging surface is specifically:

[0098]

[0099] Among them, U3(u, v) is the complex number of the target light wave field, including amplitude and phase;

[0100] A2(u, v) is the light field amplitude of the incident light wave at the target imaging surface;

[0101] Φ target (u, v) is the target phase information corresponding to the target light wave on the target imaging surface;

[0102] Perform an inverse Fourier transform on the light field of the target light wave at the target imaging surface to determine the light field corresponding to the new free-form surface mirror formed by the target light wave:

[0103]

[0104] Among them, U4(x, y) is the light field corresponding to the new free-form surface mirror formed by the target light wave, and the target mirror reflection phase Φ4(x, y) of the target light wave corresponding to the new free-form surface mirror is determined.

[0105] In step 403, the method for calculating the error coefficient between the target surface parameters of the free-form surface mirror and the initialization surface parameters of the free-form surface mirror is:

[0106] Calculate the error between the target surface parameters of the free-form mirror and the initialization surface parameters of the free-form mirror:

[0107] ΔΦ(x,y)=Φ4(x,y)-Φ1(x,y);

[0108] Based on the error between the target surface parameters of the free-form surface mirror and the initialization surface parameters of the free-form surface mirror, the distribution shape of the free-form surface mirror is updated:

[0109] z(x, y)=z(x, y)+α·f(ΔΦ(x, y));

[0110] z(x, y) is the height distribution of the free-form mirror;

[0111] α is the growth factor, which is used to control the update rate;

[0112] f(ΔΦ(x, y)) is a mapping function used to adjust the height of the free-form mirror, which is usually related to the wavelength of the incident broadcast and the material properties of the free-form mirror.

[0113] This embodiment gradually corrects the shape of the free-form mirror to meet the requirements of high-precision imaging, thereby reducing optical defects. Through the precise design of the free-form mirror, the coordination of the reflector, and the optimization of the image source position and system layout, this patent effectively reduces optical defects such as distortion, coma, spherical aberration and astigmatism in the system. These designs not only ensure high-quality three-dimensional display effects, but also improve the compactness and space utilization of the optical system.

[0114] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. A three-dimensional display system using multi-focal plane display technology, characterized in that: include: An image source (1) is formed into at least two logically separated areas, and the image source (1) is used to provide light field data with different depth information; A reflector (2) is installed on the opposite side of each separation area of ​​the image source (1) and is distributed off-axis from the installation position of the image source (1), and the light generated by the image source (1) is reflected by the reflector (2); The free-form surface mirror (3) is arranged off-axis from the installation positions of the image source (1) and the reflector (2), and adjusts and reflects the light from the reflector (2). Through the reflection effect of the free-form surface mirror (3), the light is respectively gathered through the space between the reflectors (2) and guided to the human eye, and finally an image is formed at the target imaging surface.

2. The three-dimensional display system using multi-focal plane display technology according to claim 1, characterized in that: The two separation areas of the image source (1) are arranged in parallel, and absorption walls are provided on both sides of each separation area of ​​the image source (1), and the absorption walls prevent the light rays generated by two adjacent image sources (1) from intersecting.

3. The three-dimensional display system using multi-focal plane display technology according to claim 1, characterized in that: The reflectors (2) are respectively located on both sides of the free-form surface mirror (3), and the space between the two reflectors (2) is capable of allowing light reflected by the free-form surface mirror (3) to pass through.

4. A method for realizing a three-dimensional display system using multi-focal plane display technology based on any one of claims 1 to 3, characterized in that: The following steps are involved: Step 100, constructing a spherical off-axis system of an image source, a reflector, and a free-form surface mirror, so that the reflector and the free-form surface mirror are distributed at desired spatial positions, and obtaining an initial structure of a three-dimensional display system; Step 200, determining an image source installation position and a human eye observation position, and determining an incident light wave of the image source and an outgoing light wave after the incident light wave is reflected by the free-form surface mirror based on the image source installation position and the human eye observation position, so that the outgoing light wave enters the human eye; Step 300, initializing the surface parameters of the free-form surface mirror, setting the initialization surface parameters of the free-form surface mirror, and calculating the influence of the initialization surface parameters of the free-form surface mirror on the incident light wave to obtain the initial outgoing light wave; Step 400, optimizing the surface parameters of the free-form surface mirror, optimizing the surface parameters of the free-form surface mirror in the three-dimensional display system of the initial structure, so that the phase of the outgoing light wave formed by the free-form surface mirror can exactly correspond to the observation position of the human eye.

5. The method for realizing a three-dimensional display system using multi-focal plane display technology according to claim 4, characterized in that: In step 400, the method for optimizing the surface parameters of the free-form surface mirror is as follows: Step 401, using ray tracing technology to calculate the outgoing light wave after being reflected from the initialized free-form surface mirror, performing Fourier transform on the outgoing light wave, and determining the phase information and amplitude information corresponding to the outgoing light wave when propagating to the target imaging surface; Step 402, determining the target light wave phase information corresponding to the target imaging surface, performing an inverse Fourier transform on the target light wave phase information, and determining the target surface parameters of the free-form surface mirror corresponding to the target light wave; Step 403, calculating the error coefficient between the target surface parameters of the free-form surface mirror and the initialization surface parameters of the free-form surface mirror, and adjusting its curvature or off-axis parameters by using an optimization strategy so that the phase of the outgoing light is closer to the target light wave phase information; Step 404: Use iterative optimization to gradually modify the curved surface shape of the free-form mirror until convergence, so that the phase and amplitude of the incident light wave after the free-form mirror-type reflection can match the required phase distribution.

6. The method for realizing a three-dimensional display system using multi-focal plane display technology according to claim 5, characterized in that: In step 401, the method for determining the phase information and amplitude information corresponding to the outgoing light wave when it propagates to the target imaging surface is: Calculate the light field of the incident light wave emitted by the image source after being reflected by the free-form surface mirror: Among them, U1(x, y) is the complex number of the incident light wave field; A1(x, y) is the amplitude of the incident light wave field, which usually depends on the light intensity of the incident light wave; Φ1(x, y) is the phase distribution after reflection by the free-form surface mirror; Perform Fourier transform on the light field reflected by the free-form surface mirror to calculate the distribution of the incident light field at the target imaging surface: Among them, U2(u, v) is the light field distribution of the incident light wave at the target imaging surface, including the amplitude A2(u, v) and the phase Φ2(u, v).

7. The method for realizing a three-dimensional display system using multi-focal plane display technology according to claim 5, characterized in that: In step 402, the method for determining the target surface parameters of the free-form surface mirror corresponding to the target light wave is as follows: The amplitude of the outgoing light wave after being reflected by the initialized free-form surface mirror at the target imaging surface is kept constant, and the phase distribution of the outgoing light wave is adjusted so that the phase distribution of the outgoing light wave is close to the phase distribution of the target light wave; At the target imaging surface, determine the target light wave phase information Φ corresponding to the target imaging surface target (u, v), the light field of the target light wave at the target imaging plane is specifically: Among them, U3(u, v) is the complex number of the target light wave field, including amplitude and phase; A2(u, v) is the light field amplitude of the incident light wave at the target imaging surface; Φ target (u, v) is the target phase information corresponding to the target light wave on the target imaging surface; Perform an inverse Fourier transform on the light field of the target light wave at the target imaging surface to determine the light field corresponding to the new free-form surface mirror formed by the target light wave: Among them, U4(x, y) is the light field corresponding to the new free-form surface mirror formed by the target light wave, and the target mirror reflection phase Φ4(x, y) of the target light wave corresponding to the new free-form surface mirror is determined.

8. The method for realizing a three-dimensional display system using multi-focal plane display technology according to claim 7, characterized in that: In step 403, the method for calculating the error coefficient between the target surface parameters of the free-form surface mirror and the initialization surface parameters of the free-form surface mirror is: Calculate the error between the target surface parameters of the free-form surface mirror and the initialization surface parameters of the free-form surface mirror: ΔΦ(x,y)=Φ4(x,y)-Φ1(x,y); Based on the error between the target surface parameters of the free-form surface mirror and the initialization surface parameters of the free-form surface mirror, the distribution shape of the free-form surface mirror is updated: z(x, y)=z(x, y)+α·f(ΔΦ(x, y)); z(x, y) is the height distribution of the free-form surface mirror; α is the growth factor, which is used to control the update rate; f(ΔΦ(x, y)) is a mapping function used to adjust the height of the free-form surface mirror, which is usually related to the wavelength of the incident broadcast and the material properties of the free-form surface mirror.

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