A polarization multiplexing based large depth of field light field near-eye display device and method

Abstract

A kind of big depth of field light field near-to-eye display device and method based on polarization multiplexing.The device includes display screen, virtual image adjusting module, real image adjusting module, total controller, drive module, optional optical power compensation lens and optional diopter compensation lens.Via virtual image adjusting module and real image adjusting module respectively regulate virtual image and real world light, so that both are imaged in design distance after entering human eye, realize virtual and real confocal display;Total controller is used to generate multiple depth light field image, and according to the difference of light field image, control drive module output voltage, so as to adjust the focal length of the above two image adjusting devices;In the process of light field image switching, the voltage of drive module is synchronously adjusted.The present application can realize the clear fusion of multiple depth three-dimensional virtual image and real image by zero optical power design, has good imaging quality and visual comfort, and is suitable for augmented reality and other near-to-eye display scenarios.

Description

Technical Field

[0001] This invention relates to the field of near-eye display technology, and more specifically, to a near-eye display device and method with large depth of field based on polarization multiplexing. Background Technology

[0002] In recent years, near-eye light field display has become an important development direction for 3D display technologies such as augmented reality (AR) and virtual reality (VR), attracting widespread attention due to its advantages such as naturally presenting depth cues and reducing eye strain. Traditional light field display systems mostly rely on microlens arrays or integrated imaging structures to reproduce spatial light fields by recording and reconstructing two-dimensional images from multiple viewpoints. However, limited by panel size, lens size, and arrangement, such systems have a limited depth range in actual imaging, making it difficult to achieve continuous and clear multi-depth image reconstruction. Furthermore, because traditional light field display systems only provide binocular convergence cues through parallax information and fail to synchronously guide the accommodation process of the human eye's lens, they are prone to convergence-accommodation conflict, leading to visual fatigue and image discomfort. Therefore, constructing a near-eye display system that combines multi-depth image reconstruction capabilities with good visual comfort has become one of the key challenges in light field display research.

[0003] To address the limitations of depth of field and the convergence-accommodation conflict, recent research has explored multi-plane image reconstruction techniques. These techniques utilize multi-layer stacking, dynamic zoom lenses, and acousto-optic modulation to mitigate these conflicts. However, the complex system structure, high power consumption, and stringent timing synchronization requirements hinder its widespread application in lightweight, low-cost near-eye displays. In response, recent research has proposed introducing polarization multiplexing technology into light field display systems. This technology utilizes the polarization state of light waves as independent information channels, achieving the modulation and multiplexing of multi-channel images while maintaining a compact system structure. This provides a new solution for constructing simple, efficient, and stable multi-depth light field near-eye display systems. However, existing polarization multiplexing technologies are primarily used in naked-eye displays and cannot meet the needs of near-eye displays. Especially when applied to AR displays, users cannot simultaneously observe the real world and a stereoscopic 3D virtual image.

[0004] Patent document US20220299786(A1) proposes a multi-plane optical perspective augmented reality (AR) display system that utilizes a custom-designed reflective polarization-dependent lens (PDL) to guide light to two different virtual focal planes through two different polarization states, thereby mitigating the convergence-accommodation contradiction. This system is compact, lightweight, and does not cause visual fatigue when worn, making it suitable for efficient and lightweight AR devices. Patent document CN116719174A proposes a large depth-of-field integrated imaging 3D display system based on a polarization-multiplexed superlens array, including a microdisplay, a polarization-multiplexed superlens array, and a polarization modulator. The image source light emitted from the microdisplay first passes through the polarization-multiplexed superlens array and then through the polarization modulator. The polarization-multiplexed superlens array modulates the two different orthogonally polarized beams of light emitted from the microdisplay, focusing them onto different focal planes, thereby reconstructing 3D images within two different depth ranges. This invention uses a polarization modulator to control the polarization of the emitted light, achieving image switching between reconstructed ranges at different depths, thus realizing integrated imaging 3D display with extended depth of field. However, the two methods mentioned above have certain drawbacks when applied to AR displays. Method 1, although it can display images at multiple depths through lenses, cannot directly present three-dimensional images with depth variations. Method 2, although it modulates images using polarizing microlenses and allows users to observe three-dimensional virtual images with depth variations, only modulates a single layer of the virtual image and cannot observe the real world. Summary of the Invention

[0005] To address the problems of limited depth of field, convergence-accommodation conflict, and difficulty in fusing virtual and real images in existing near-eye display technologies, this invention provides a near-eye display device and method with a large depth of field based on polarization multiplexing. Through double-layer polarization multiplexing and dynamic light field modulation, it achieves cofocal display of virtual images and real-world light, and has significant advantages such as compact structure, clear imaging, and visual comfort.

[0006] The technical solution of the present invention is as follows:

[0007] A near-eye display device with large depth of field based on polarization multiplexing, characterized in that it includes:

[0008] The display screen uses a transparent LED, OLED, or MicroLED display panel to provide a virtual light field image source for three-dimensional display. Its signal input terminal is connected to the main controller, which can realize the display and rapid switching of light field images.

[0009] The virtual image adjustment module is located on the light-emitting side of the display screen and includes a first linear polarizer, a first fast polarization modulator, a first quarter-wave plate, and a first polarizing flat microlens array arranged in sequence.

[0010] The real image adjustment module is located on the non-light-emitting side of the display screen and includes a second linear polarizer, a second fast polarization modulator, a second quarter-wave plate, and a second polarizing flat microlens array arranged in sequence.

[0011] The main controller is used to generate multi-depth light field images and control the display screen and drive module;

[0012] The driving module consists of a first driving module and a second driving module, which are respectively connected to the first fast polarization modulator and the second fast polarization modulator, and are used to adjust the focal length of the virtual image adjustment module and the real image adjustment module according to the instructions of the main controller.

[0013] The virtual image adjustment module and the real image adjustment module together constitute a zero-focal-length optical system, which enables both virtual images and real-world light to be imaged at the designed distance.

[0014] Preferably, the virtual image adjustment module and the real image adjustment module are respectively attached to the two side surfaces of the display screen, and satisfy 1 / f 1,2 =1 / f1+1 / f2-d 12 / f1f2, where f1 and f2 are the focal lengths of the first and second polarizing plate microlens arrays, respectively, and d 12 It is the distance between the first polarizing flat plate microlens array and the second polarizing flat plate microlens array, and d 12 ≈0, f1=-f2, f 1,2 ≈∞.

[0015] Preferably, the virtual image adjustment module and the real image adjustment module are respectively disposed on the light-emitting side and the non-light-emitting side of the display screen. That is, when there is a non-zero gap between the first polarizing flat plate microlens array and the second polarizing flat plate microlens array, an optical power compensation lens is also included, disposed in the optical path between the virtual image adjustment module and the real image adjustment module, with its optical axis coinciding with the normal of the display screen, for compensating for optical power, wherein optical power is the reciprocal of focal length and satisfies the following formula:

[0016] 1 / f 1,2,3 = 1 / f1 + 1 / f2 + 1 / f3 - d 12 / f1f2-d 13 / f1f3-d 23 / f2f3+d 12 d 23 / f1f2f3 where f1, f2, and f3 are the focal lengths of the first polarizing flat plate microlens array, the second polarizing flat plate microlens array, and the optical power compensation lens, respectively, and d 12 d is the distance between the first polarizing flat plate microlens array and the second polarizing flat plate microlens array. 13It is the distance d between the second polarizing flat microlens array and the optical power compensation lens. 23 It is the distance between the first polarizing flat microlens array and the optical power compensation lens, and f 1,2，3 ≈∞.

[0017] Preferably, the virtual image adjustment module and the real image adjustment module are respectively located on the light-emitting side and the non-light-emitting side of the display screen. That is, when there is a non-zero gap between the first polarizing flat microlens array and the second polarizing flat microlens array, a diopter compensation lens is also included to adjust the imaging distance according to the user's vision, so that nearsighted or farsighted users can clearly observe the virtual-real fusion image without wearing an additional correction device.

[0018] Preferably, the diopter compensation lens is mounted on the side close to the human eye via a sliding bracket, and its diopter adjustment range is -6D to +3D. Its position can be adjusted along the optical axis according to the user's vision.

[0019] Preferably, the main controller acquires multi-depth light field images through a light field image acquisition program, and its control signal output terminal is connected to the display screen and the driving module respectively to control the display and switching of parallax images and the output of the driving device voltage.

[0020] Preferably, during the process of the main controller synchronously controlling the switching of the light field image and the output voltage of the driving module, there is a one-to-one matching relationship between the light field image, the virtual image adjustment module, and the real image adjustment module: when the display screen displays light field image 1, the first driving module controls the fast polarization modulator of the virtual image adjustment module to output linearly polarized light with a polarization direction of -45°, and controls the fast polarization modulator of the real image adjustment module to output linearly polarized light with a polarization direction of +45°; when the display screen displays light field image 2, the second driving module controls the first fast polarization modulator of the virtual image adjustment module to output linearly polarized light with a polarization direction of +45°, and controls the first fast polarization modulator of the real image adjustment module to output linearly polarized light with a polarization direction of -45°.

[0021] Preferably, the driving module is a voltage adjustment device that can synchronously control the output voltage to adjust the focal length of the virtual image adjustment module and the real image adjustment module according to the light field image information, so that the equivalent optical power of the near-eye 3D display device is zero.

[0022] Preferably, both the first and second polarizing flat plate microlens arrays contain i×j periodically arranged sub-lens units, where i and j are the number of rows and columns, respectively. Each sub-lens unit of the first polarizing flat plate microlens array corresponds one-to-one with a sub-image region of the corresponding light field image on the display screen, thereby achieving light field modulation. When all sub-images pass through the first polarizing flat plate microlens array, a three-dimensional light field display effect will be presented. The real-world image is modulated by the first and second polarizing flat plate microlens arrays, superimposing the real environment image onto the human eye's field of vision.

[0023] The present invention also provides a method for a large depth-of-field near-eye display device based on polarization multiplexing, which, using the above-mentioned device, is characterized by including the following steps:

[0024] Step 1: The main controller acquires light field images 1 and 2 at different display depths through the light field image acquisition program;

[0025] Step 2: The main controller controls the display screen to show light field image 1 and controls the output voltage of the drive module;

[0026] Step 3: The first driving module controls the virtual image adjustment module to be in state 1, while the second driving module controls the real image adjustment module to be in state 2.

[0027] Step 4: The main controller switches the display screen to show light field image 2 and controls the output voltage of the drive module;

[0028] Step 5: The first driving module controls the virtual image adjustment module to be in state 2, while the second driving module controls the real image adjustment module to be in state 1.

[0029] Step 6: Repeat steps 2-5 to achieve continuous display of multi-depth light fields.

[0030] Preferably, in state 1, the fast polarization modulator outputs -45° linearly polarized light, which is converted into left-handed circularly polarized light by a quarter-wave plate, and the polarization plate microlens array focuses it at -f; in state 2, the fast polarization modulator outputs +45° linearly polarized light, which is converted into right-handed circularly polarized light by a quarter-wave plate, and the polarization plate microlens array focuses it at +f.

[0031] Compared with the prior art, the present invention has the following obvious and prominent substantive features and significant advantages:

[0032] The device of this invention employs a virtual image adjustment module that combines a linear polarizer, a fast polarization modulator, a quarter-wave plate, and a polarizing flat microlens array into a display module. This method can filter stray light from the environment and divide the virtual 3D image into multiple depth planes, ultimately constructing a 3D light field image with continuously varying depth. This approach simplifies the size of the display module and provides a key component for the lightweight miniaturization of near-eye light field displays.

[0033] This invention uses a virtual image adjustment module and a real image adjustment module as the core components for light field modulation. When the two modules are close together or the distance between them is negligible, an optical design with zero equivalent optical power is achieved by adjusting the focal length of the two modules. When there is a distance between the two modules, this invention introduces an optical power compensation lens to adjust the system's optical power, achieving an optical design with zero equivalent optical power. Through the system's zero optical power design, both the virtual and real images are imaged at the designed distance, allowing the human eye to simultaneously observe both the three-dimensional virtual and real images.

[0034] This invention introduces a refractive error compensation lens. When a user has visual impairment, the position and focal length of the refractive error compensation lens are adjusted according to the user's specific situation, so that the user can clearly observe the fused image without wearing additional glasses or other equipment. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of a large depth-of-field near-eye display device based on compact polarization multiplexing, provided in Embodiment 1 of the present invention.

[0036] Figure 2 The optical path diagram for imaging virtual and real images in a large depth-of-field near-eye display device based on compact polarization multiplexing, as provided in Embodiment 1 of the present invention.

[0037] Figure 3 (a) and Figure 3 (b) are the modulation principle diagrams of the virtual image adjustment module on the image light in two states.

[0038] Figure 4 This is a schematic diagram of a large depth-of-field near-eye display device based on polarization multiplexing, provided in Embodiment 2 of the present invention.

[0039] Figure 5 This is an optical path diagram of the imaging of a virtual image and a real image in a near-eye display device with a large depth of field based on polarization multiplexing, as provided in Embodiment 2 of the present invention.

[0040] Figure 6 This is a schematic diagram of a near-eye display device with large depth of field and adaptive light field based on polarization multiplexing, provided in Embodiment 3 of the present invention.

[0041] Figure 7 The optical path diagram for imaging virtual and real images in a polarization-multiplexed large depth-of-field diopter adaptive light field near-eye display device provided in Embodiment 3 of the present invention.

[0042] Figure 8 This is a schematic flowchart of the large depth-of-field near-eye display method based on polarization multiplexing provided in Embodiments 1, 2 and 3 of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. The above solutions will be further described below with reference to specific embodiments. Preferred embodiments of the present invention are detailed below:

[0044] Example 1

[0045] This embodiment provides a large depth-of-field near-eye display device based on polarization multiplexing. For example... Figure 1 As shown, the compact polarization multiplexing large depth-of-field light field near-eye display device includes a display screen 100, a virtual image adjustment module 110, a real image adjustment module 120, a main controller 130, and a drive module.

[0046] The display screen 100 is a transparent display panel, which can be an LED, OLED, MicroLED, or other display device, possessing high transmittance and a thin and light profile. This display screen can display images from one side, presenting monochrome or color images, meeting the basic imaging quality requirements of compact, polarization-multiplexed, large-depth-of-field near-eye display devices. Simultaneously, its high transmittance ensures users can clearly observe the surrounding real world. The display screen 100 is connected to a main controller 130, which adjusts its image display content and refresh sequence, and works in conjunction with the virtual image adjustment module 110, the real image adjustment module 120, and the drive module. When the display screen provides a monochrome image source, the monochrome image input parameters need to match the parameters of the virtual image module 110; when the display screen provides a color image source, the color image input parameters need to match the parameters of the virtual image module 110, thereby improving the diffraction efficiency after light modulation and the clarity of three-dimensional imaging. To match the two working states of the virtual image adjustment module, the display screen needs to alternately display light field images corresponding to the two depth planes. Specifically, when the display screen shows the content of light field image 1, the focal length of the virtual image adjustment module 110 is adjusted to -f; when the display screen shows the content of light field image 2, the focal length of the virtual image adjustment module 110 is adjusted to +f.

[0047] The virtual image adjustment module 110 consists of a first linear polarizer 1101, a first fast polarization modulator 1102, a first quarter-wave plate 1103, and a polarizing flat microlens array 1104. This module is attached to the light-emitting side surface of the display screen 100 and is used to receive and modulate the light field image from the display screen. Figure 2 As shown, the light from the display screen 100 first passes through the virtual image adjustment module 110 along the direction of the dotted arrow in the figure, and then diverges through the microlens into the human eye, finally forming an image at the designed distance.

[0048] The real image adjustment module 120 consists of a second linear polarizer 1201, a second fast polarization modulator 1202, a second quarter-wave plate 1203, and a second polarizing flat microlens array 1204. The real image adjustment module 120 is located on the non-light-emitting side (transparent side) of the display screen 100 and is also in close contact with the surface of the display screen 100. It is used to adjust the optical power of the compact polarization multiplexed large depth-of-field near-eye display device, ensuring that the virtual image can be fused with the real scene. Its overall structure and basic principle are basically the same as those of the virtual image adjustment module 110. In natural scenes, light from the external world can be approximated as parallel light. Figure 2 As shown, light from the real world first passes through the real image adjustment module 120 along the solid arrow in the diagram. The modulated light then passes through the virtual image modulation device 110, and finally enters the human eye and is imaged at the designed distance. The compact polarization multiplexed large depth-of-field near-eye display device forms an optical system with an equivalent optical power of zero through the combination structure of the real image adjustment module 120 and the virtual image modulation device 110. This ensures that both the virtual image and the real-world image output by the system are imaged at the designed distance after entering the human eye through the display device. When the human eye is located behind the virtual image adjustment module 110, because the virtual image adjustment module 110 and the real image adjustment module 120 work together to form a system with an equivalent optical power of zero, the human eye can not only observe the modulated virtual image light, but also simultaneously see the real-world image and superimpose the real-world image into the field of vision, achieving a virtual-real confocal display, that is, the human eye can simultaneously see the real-world image and the virtual image. The optical power of the compact polarization multiplexed large depth-of-field near-eye display device is always zero, so that both the real world and virtual images are imaged at infinity. Users can clearly perceive virtual and real information while having visual perspective consistency, which meets the comprehensive requirements of augmented reality systems for virtual and real confocality and visual comfort.

[0049] The main controller 130 is a control device, which can be a microcontroller, Raspberry Pi, FPGA, PLC, or other microcontroller. It coordinates the timing control of light field image generation and switching, as well as output voltage modulation. The main controller 130 can generate light field images of different depths by controlling the light field image acquisition program. Simultaneously, the main controller 130 is connected to the display screen 100, specifically using a DP or HDMI interface to display the light field images on the display screen 100 and control their rapid switching. Furthermore, the main controller 130 is electrically connected to the driver module and can control the driver's output voltage. The main controller 130 needs to synchronously control the switching of the light field images and the changes in the output voltage of the driver module to ensure a one-to-one correspondence between the light field images and the voltage state of the driver module, achieving precise control of the image light.

[0050] The driving module, consisting of a first driving module 140 and a second driving module 141, is a voltage regulation device. It can be a high-frequency voltage driver, a square wave driver, or other voltage driving device, and is connected to the main controller 130, enabling rapid adjustment of the driver's output voltage. The first driving module 140 and the second driving module 141 are respectively connected to the fast polarization modulators of the virtual image adjustment module 110 and the real image adjustment module 120. Specifically, the first driving module 140 and the second driving module 141 can be connected to the fast polarization modulator via USB, RS232, or CAN interfaces for controlling and outputting voltage parameters. By controlling the voltage of the fast polarization modulator through the driving module, the orientation of the liquid crystal molecules inside the fast polarization modulator is adjusted, thereby modulating the polarization state or phase delay of the transmitted light. The main controller 130 controls the display screen 100 to display light field images. When displaying light field image 1, the main controller 130 adjusts the first drive module 140 to state 1, and simultaneously adjusts the second drive module 141 to state 2. When displaying light field image 2, the main controller 130 adjusts the first drive module 140 to state 2, and simultaneously adjusts the second drive module 141 to state 1. The two drive modules are simultaneously in two different states to maintain the relationship that the optical power of the virtual image adjustment module 110 and the focal length of the real image adjustment module 120 are equal in magnitude and opposite in direction, thereby ensuring that the overall equivalent optical power of the system is zero, ensuring that the human eye can clearly perceive the real world while observing virtual content.

[0051] Figure 3 (a) and Figure 3 (b) The diagrams show the modulation principle of the first fast polarization modulator 1102 of the virtual image adjustment module 110 on the image light under two polarization states. Figure 3(a) illustrates that when the incident light makes a -45° angle with the optical axis of the first fast polarization modulator 1102, the image light first passes through the first linear polarizer 1101, filtering out unpolarized stray light and retaining only the polarized light component. The first fast polarization modulator 1102 modulates the polarization direction of the polarized light to -45°. Then, the first quarter-wave plate 1103 modulates the light into left-handed circularly polarized light. Finally, the first polarizing flat microlens array 1104 focuses the image at the position -f. Similarly, Figure 3 (b) illustrates that when the incident light makes a +45° angle with the optical axis of the first fast polarization modulator 1102, the image light first passes through the first linear polarizer 1101, filtering out unpolarized stray light and retaining only the polarized light component. The first fast polarization modulator 1102 modulates the polarization direction of the polarized light to +45°. Then, the first quarter-wave plate 1103 modulates the light into right-hand circularly polarized light. Finally, the first polarizing flat microlens array 1104 focuses the image at the +f position. The light modulation principle of the real image adjustment module 120 is similar to... Figure 3 (a) and Figure 3 (b) Similar.

[0052] The first linear polarizer 1101 and the second linear polarizer 1201 are optical filters made of polarizing films, whose light transmittance is directly related to the polarization state of the incident light. The first linear polarizer 1101 is disposed on the light-emitting side of the display screen 100 to filter out unpolarized stray light output from the display screen; the second linear polarizer 1201 is disposed on the non-light-emitting side of the display screen to filter out unpolarized stray light from ambient light. Both allow only linearly polarized light with a specific vibration direction to pass through. By suppressing unwanted polarization components, the linear polarizers can effectively eliminate strong reflected light on the display interface, reduce glare interference in the system, and significantly improve image contrast.

[0053] The first fast polarization modulator 1102 and the second fast polarization modulator 1202 are polarization control devices based on liquid crystal technology. They control the alignment of liquid crystal molecules by adjusting the applied voltage, thereby achieving dynamic modulation of the polarization direction of incident linearly polarized light. The first fast polarization modulator 1102 is installed after the first linear polarizer 1101, and the second fast polarization modulator 1202 is installed after the second linear polarizer 1201 to receive the output linearly polarized light. Under the action of the driving module, the fast polarization modulators can rotate the incident linearly polarized light to ±45°, with the specific polarization angle depending on the current voltage parameters. Specifically, when the display screen 100 displays light field image 2, the first driving module 140 adjusts the polarization direction of the first fast polarization modulator 1102 so that the polarization direction of the emitted ray-polarized light passing through the first fast polarization modulator 1102 is +45°, and at the same time, the second driving module 141 adjusts the polarization direction of the second fast polarization modulator 1202 so that the polarization direction of the emitted ray-polarized light passing through the second fast polarization modulator 1202 is -45°; in addition, when the display screen 100 displays light field image 1, the first driving module 140 adjusts the polarization direction of the first fast polarization modulator 1102 so that the polarization direction of the emitted ray-polarized light passing through the first fast polarization modulator 1102 is -45°, and at the same time, the second driving module 141 adjusts the polarization direction of the second fast polarization modulator 1202 so that the polarization direction of the emitted ray-polarized light passing through the second fast polarization modulator 1202 is +45°. By synchronously controlling the image switching of the display screen 100 and the voltage output control of the driving module, the driving voltage of the first fast polarization modulators 1102 and 1202 is adjusted to achieve precise matching between the polarization direction and the image content.

[0054] The first quarter-wave plate 1103 and the second quarter-wave plate 1203 are birefringent single-crystal optical elements that can separate the orthogonal polarization components of incident light through the refractive characteristics of their slow and fast axes. Due to the difference in refractive index between the slow and fast axes, the two polarization components have different propagation speeds, thus generating a fixed π / 2 phase difference in the optical field. The first quarter-wave plate 1103 is installed behind the first fast polarization modulator 1102, while the second quarter-wave plate 1203 is installed behind the second fast polarization modulator 1202. The optical axis of the quarter-wave plate is kept strictly parallel to the optical axis of the linear polarizer to ensure the polarization modulation consistency of the optical path system. When linearly polarized light modulated by the fast polarization modulator is incident on the quarter-wave plate at an angle of -45° or +45°, the linearly polarized light will be converted into circularly polarized light. Specifically, when linearly polarized light at -45° is incident, the phase delay of the fast-axis component causes the light field to exhibit a left-handed circularly polarized state; conversely, when linearly polarized light at +45° is incident, the phase delay of the slow-axis component generates a right-handed circularly polarized state. This polarization state conversion is achieved by controlling the relative angle between the linearly polarized light and the optical axis of the quarter-wave plate, and it exhibits high reversibility and stability. This design, through precise timing and angle matching, ensures that the 3D display system presents a clear and stable light field distribution under different viewing angles, effectively suppressing image crosstalk and artifacts.

[0055] The first polarizing flat plate microlens array 1104 and the second polarizing flat plate microlens array 1204 are geometric phase-type optical elements, integrated from a polymer liquid crystal film and an N-BK7 window substrate. By controlling the anisotropic structure of the liquid crystal polymer, this array can focus incident light with different circular polarization states at different positions, achieving collimation and wavefront shaping of the incident light. The device contains i×j periodically arranged sub-lens units (where i and j are the number of rows and columns, respectively). Each sub-lens unit of the first polarizing flat plate microlens array 1104 corresponds one-to-one with a sub-image area in the display screen 100, thereby achieving precise light field modulation. When all sub-images pass through the first polarizing flat plate microlens array 1104, a three-dimensional light field display effect will be presented. The first polarizing flat plate microlens array 1104 is located behind the first quarter-wave plate 1103, while the second polarizing flat plate microlens array 1204 is located behind the second quarter-wave plate 1203, used for light field modulation of the circularly polarized light output from the quarter-wave plate. Preferably, a polarizing flat plate microlens array with an optical transmission window limited to a wavelength of 532 nm is used. Therefore, the dominant wavelength of the spectral output of the display screen 100 needs to be synchronously stabilized in the 532±5 nm band to ensure that all display light can effectively pass through the array. The polarizing flat plate microlens array utilizes the differentiated modulation characteristics of left-handed and right-handed circularly polarized light. When right-handed circularly polarized light enters the polarizing flat plate microlens array, the light will focus at +f; while when left-handed circularly polarized light enters the polarizing flat plate microlens array, the light will diverge, with a focal length of -f. The formula for calculating the optical power of the two lens combination system is as follows: 1 / f 1,2 =1 / f1+1 / f2-d 12 / f1f2. Where f1 and f2 are the focal lengths of the first polarizing flat microlens array 1104 and the second polarizing flat microlens array 1204, respectively, and d 12 The distance between the first polarizing flat microlens array 1104 and the second polarizing flat microlens array 1204. Since these two microlens arrays are close to the two surfaces of the display screen, the screen thickness is negligible, and d... 12 ≈0, and f1 and f2 have the same value but opposite signs, so f 1,2 When the optical power is approximately zero (≈∞), the system's optical power is approximately zero, which is the "no optical power" state. By adjusting the first fast polarization modulators 1102 and 1202 to maintain a 90° phase difference, the circular polarization of the light rays passing through the first quarter-wave plates 1103 and 1203 is different. This ensures that the focal lengths of the first polarizing flat microlens arrays 1104 and 1204 maintain a positive-negative complementary relationship, keeping the system's optical power always zero.

[0056] Furthermore, by switching the light field image on the display screen, the virtual image can exhibit multiple levels of variation. During the adjustment process, the light field image forms a strict correspondence with the polarization direction of the two sets of fast polarization modulators. The main controller 130 outputs light field image 1 to the display screen 100. The main controller 130 synchronously controls the first drive module 140 to adjust the input voltage of the first fast polarization modulator 1102 so that its optical axis forms a -45° angle with the incident polarized light. The first quarter wave plate 1103 modulates the incident linearly polarized light into left-handed circularly polarized light. The left-handed circularly polarized light is modulated by the first polarizing plate microlens array 1104 and focused at -f. At the same time, the main controller 130 synchronously controls the second drive module 141 to adjust the input voltage of the second fast polarization modulator 1202 so that its optical axis forms a +45° angle with the incident polarized light. The second quarter wave plate 1203 modulates the incident linearly polarized light into right-handed circularly polarized light. The right-handed circularly polarized light is modulated by the second polarizing plate microlens array 1204 and focused at +f. After the shaped virtual image beam enters the human eye, it is imaged at the designed distance, while the light from the real world also enters the human eye and is imaged at the designed distance. Therefore, the human eye can clearly observe both the virtual image and the real world at the same time. Similarly, the main controller 130 outputs light field image 2 to the display screen 100; the main controller 130 synchronously controls the first drive module 140 to adjust the input voltage of the first fast polarization modulator 1102 so that its optical axis forms a +45° angle with the incident polarized light, the first 1 / 4 wave plate 1103 modulates the incident linearly polarized light into right-hand circularly polarized light, and the right-hand circularly polarized light is focused at +f after being modulated by the first polarizing plate microlens array 1104; at the same time, the main controller 130 synchronously controls the second drive module 141 to adjust the input voltage of the second fast polarization modulator 1202 so that its optical axis forms a -45° angle with the incident polarized light, the second 1 / 4 wave plate 1203 modulates the incident linearly polarized light into left-hand circularly polarized light, and the left-hand circularly polarized light is focused at -f after being modulated by the second polarizing plate microlens array 1204. The strict correspondence between the polarization state of the polarization modulator and the image content ensures consistent image sharpness and depth during image switching, while maintaining a 90° phase difference between the first fast polarization modulator 1102 and the second fast polarization modulator 1202. Any phase deviation will cause circular polarization shift, leading to image blurring, depth misalignment, or even failure of virtual-real fusion. By precisely controlling the polarization angle and matching the image sequence, the main controller 130 achieves continuous display of multi-depth virtual images, ensuring that the real and virtual images are always imaged at a designed distance, and can be focused on the retina after entering the human eye, thus achieving clear virtual-real fusion.

[0057] This embodiment proposes a large depth-of-field near-eye display device based on compact polarization multiplexing. The complete system consists of a display screen 100, a virtual image adjustment module 110, a real image adjustment module 120, a main controller 130, and a drive module. The virtual image adjustment module 110 and the real image adjustment module 120 are placed close to the two surfaces of the display screen 100. The main controller 130 controls the output voltage of the drive module, adjusting the focal lengths of the virtual image adjustment module 110 and the real image adjustment module 120 to maintain a positive-negative complementary relationship. This achieves an optical design with zero equivalent optical power, ensuring that both real-world light and virtual image light are imaged at the designed distance, guaranteeing the comfort and clarity of the fusion visual experience. In the specific operation, the main controller 130 coordinates the generation and switching of the light field image and the timing control of the drive module to ensure a one-to-one correspondence between the content of the light field image and the polarization state of the two fast polarization modulators. The first drive module 140 and the second drive module 141 respectively control the fast polarization modulators of the virtual image adjustment module 110 and the real image adjustment module 120, strictly ensuring that the phase difference between the two sets of fast polarization modulators is always 90°, ensuring that the optical power of the system is zero. The display screen 100 outputs two light field images at different depths in a periodic manner. The image light is dual-modulated by the polarization plate microlens array located on the front and back sides, so that the depth of field of the virtual image is adjustable. When the virtual image light enters the virtual image adjustment module 110, it is imaged at the designed distance. The real world light first enters the real image adjustment module in the form of parallel light and is focused on the middle plane. After being modulated by the virtual image adjustment module 110, it is imaged at the designed distance. Finally, both the virtual image and the real world can be focused on the retina for imaging. This embodiment introduces a virtual image adjustment module 110 and a real image adjustment module 120 as the core of light field modulation, and constructs a near-eye display system with a compact structure, large depth of field, and virtual-real fusion, which has good feasibility and scalability.

[0058] Example 2

[0059] This embodiment provides another near-eye display device with large depth of field based on polarization multiplexing. For example... Figure 4 As shown, the polarization-multiplexed large depth-of-field near-eye display device includes a display screen 100, a virtual image adjustment module 110, a real image adjustment module 120, a main controller 130, a drive module, and an optical power compensation lens 150.

[0060] The optical power compensation lens 150 can be either a convex or concave lens, used to compensate for the optical power of a near-eye display device with a large depth of field and polarization multiplexing. In this embodiment, there is a certain distance between the virtual image adjustment module 110 and the real image adjustment module 120 and the display screen 100. That is, when there is a non-zero distance between the first polarizing flat plate microlens array 1104 and the second polarizing flat plate microlens array 1204, adjusting the system optical power solely through the first polarizing flat plate microlens array 1104 and the second polarizing flat plate microlens array 1204 will not achieve zero optical power. Therefore, an additional device must be used to compensate and adjust the system optical power to achieve a zero optical power state. The distance between the second polarizing flat plate microlens array 1204 and the first polarizing flat plate microlens array 1104 is d. 12 The distance between the optical power compensation lens 150 and the first polarizing flat microlens array 1104 is d. 23 When the display screen 100 projects the light field image 2, the angle between the optical axis of the first fast polarization modulator 1102 of the virtual image adjustment module 110 and the incident light is 45°, and the focal length of the first polarization flat microlens array 1104 is f1; synchronously, the angle between the light of the second fast polarization modulator 1202 of the real image adjustment module 120 and the incident light is adjusted to -45°, and the focal length of the second polarization flat microlens array 1204 is f2; the focal length of the optical power compensation lens 150 is f3, and the optical power is the reciprocal of the focal length. The total optical power of the large depth-of-field near-eye display device with polarization multiplexing satisfies the formula: 1 / f 1,2,3 = 1 / f1 + 1 / f2 + 1 / f3 - d 12 / f1f2-d 13 / f1f3-d 23 / f2f3+d 12 d 23 / f1f2f3. Where |f1|=|f2|, select an optical power compensation lens 150 with a suitable focal length and place it in the correct position. Through the compensation effect of the optical power compensation lens 150 on the optical power of the system, make f 1,2，3 ≈∞, meaning the system's equivalent optical power remains zero. When the angle between the optical axis of the first fast polarization modulator 1102 of the virtual image adjustment module 110 and the incident light is -45°, the focal length of the first polarization plate microlens array 1104 is f2; synchronously adjusting the angle between the light of the second fast polarization modulator 1202 of the real image adjustment module 120 and the incident light to 45°, the focal length of the second polarization plate microlens array 1204 is f1; the optical power compensation lens 150 can continuously compensate for the system's optical power, keeping it zero.

[0061] Figure 5This is a schematic diagram of the optical path of virtual images and real-world light in a near-eye display device with a large depth of field based on polarization multiplexing. The dashed arrows represent the propagation paths of virtual image light, while the solid arrows represent the propagation paths of real-world light. When the virtual image light passes through the virtual image adjustment module 110, it is first focused on the intermediate plane, then passes through the power compensation lens 150 and enters the eye, where it is imaged at the designed distance. The real-world light is emitted in parallel form. It first passes through the real-world image adjustment module 120 and is focused on the first intermediate plane, then continues to propagate forward, passes through the virtual image adjustment module, and is focused on the second intermediate plane. Finally, the power compensation lens 150 modulates the light as it enters the eye and is imaged at the designed distance. The modulated virtual image light and the real-world light ultimately focus on the retina to form a clear image.

[0062] This embodiment provides another near-eye display device with large depth of field based on polarization multiplexing. The complete system consists of a display screen 100, a virtual image adjustment module 110, a real image adjustment module 120, a main controller 130, a driving module, and a power compensation lens 150. When there is a certain distance between the virtual image adjustment module 110 and the real image adjustment module 120 and the display screen 100, adjusting only the output voltage of the first driving module 140 and the second driving module 141 to adjust the polarization state of the fast polarization modulator and control the focal length of each optical component cannot achieve an optical design where the overall system's equivalent power is zero. Therefore, by introducing the power compensation lens 150, a power adjustment channel can be provided, effectively compensating for the system's power shift and keeping its power constant at zero. This allows the virtual image to appear at infinity in the user's field of vision, and the depth of field of the virtual image can be adjusted by the main controller. Simultaneously, the real-world scene can also be observed by the human eye, ensuring the comfort and clarity of the virtual-real fusion display effect. This embodiment introduces a virtual image adjustment module 110, a real image adjustment module 120, and an optical power compensation lens 150 as the core of light field modulation, and constructs a near-eye display system with adjustable optical power, large depth of field, and virtual-real fusion, which has good feasibility and scalability.

[0063] Example 3

[0064] This embodiment provides a large depth-of-field, diopter-adaptive near-eye display device based on polarization multiplexing. For example... Figure 6 As shown, the polarization-multiplexed large depth-of-field near-eye display device includes a display screen 100, a virtual image adjustment module 110, a real image adjustment module 120, a main controller 130, a drive module, and a diopter compensation lens 160.

[0065] The diopter compensation lens 160 can be a convex or concave lens, used to compensate for insufficient diopter adjustment of the human eye's lens when viewing a near-eye display device with a large depth of field and polarization multiplexing. In this embodiment, because there is a distance between the virtual image adjustment module 110 and the real image adjustment module 120 and the display screen 100, specifically, a non-zero gap exists between the first polarizing flat microlens array 1104 and the second polarizing flat microlens array 1204, it is impossible to achieve zero system optical power or converge the light from the virtual and real images to the same point using only the virtual image adjustment module 110 and the real image adjustment module 120. This forces the observer to adjust their own lens to clearly observe the fused virtual and real image, increasing wearing discomfort. Furthermore, for observers with visual impairments (such as myopia or hyperopia), near or distant images cannot be clearly imaged on the retina. To solve the imaging problem caused by the observer's visual impairment, this embodiment provides a diopter compensation lens 160. The refractive compensation lens 160 adjusts its focal length according to the observer's specific visual condition (such as myopia or hyperopia) and adjusts its relative distance to the virtual image adjustment module 110 and the real image adjustment module 120, thereby modulating the divergence angle of the virtual image light entering the human eye and the real image light to make them basically consistent. After being modulated by the human eye's lens, the light can be clearly imaged on the retina: for myopic observers, the refractive compensation lens 160 is configured as a concave lens to shift the retinal imaging point forward; for hyperopic observers, the refractive compensation lens 160 is configured as a convex lens to shift the retinal imaging point backward. To more intuitively illustrate the actual function of the refractive compensation lens 160, the following explanation is based on the visual characteristics of the user's refractive state: when the observer is myopic by 600 degrees (-6D), their far point is approximately 16.7 cm, meaning they can only clearly see objects within 16.7 cm. Because the virtual image and the real image in this device are projected from a distance, exceeding the user's viewing distance, image blurring will occur without compensation. Actual refractive power D eq = 1 / (fd), where f is the focal length of the diopter compensation lens 160, and d is the distance from the human eye to the diopter compensation lens 160. When the focal length of the diopter compensation lens is 200mm, according to the actual diopter calculation, the distance between the diopter compensation lens and the human eye needs to be adjusted. Therefore, the position of the diopter compensation lens 160 is adjusted to a distance of 33.3mm from the human eye, so that the human eye can clearly see the virtual image and the real image. Preferably, a diopter compensation lens 160 with a focal length of 200mm is selected, which can adjust the position of the diopter compensation lens 160 to compensate for diopter from -6D to +3D. Therefore, the diopter compensation lens 160 can not only adjust the optical power of the display system to make the divergence angle of light after the real image and the virtual image enter the human eye consistent, but also effectively compensate for the imaging blur problem caused by insufficient diopter of the human eye.

[0066] Figure 7 This is a schematic diagram of the optical path of the imaging of virtual images and real-world light in a near-eye display device with large depth of field and diopter adaptive light field based on polarization multiplexing. The dashed arrows represent the propagation paths of the virtual image light, while the solid arrows represent the propagation paths of the real-world light. When the virtual image light passes through the virtual image adjustment module 110, it is first focused on the intermediate plane, and then adjusted by the diopter compensation lens 160 before entering the human eye. The real-world light is emitted in parallel form. It first passes through the real-world image adjustment module 120 and is focused on the first intermediate plane, then continues to propagate forward through the virtual image adjustment module and is focused on the second intermediate plane. The diopter compensation lens 160 modulates the light so that the divergence angle of the light is consistent with the final divergence angle of the virtual image entering the human eye, thus allowing the real image to also enter the human eye. The modulated virtual image light and the real-world light enter the human eye with similar divergence angles. The adjusted light can meet the diopter adjustment range required by patients with visual impairment, and finally, through lens adjustment, it is focused on the retina to form a clear image.

[0067] This embodiment provides a large depth-of-field, diopter-adaptive near-eye display device based on polarization multiplexing. The complete system comprises a display screen 100, a virtual image adjustment module 110, a real image adjustment module 120, a main controller 130, a drive module, and a diopter compensation lens 160. When there is a certain distance between the virtual image adjustment module 110 and the real image adjustment module 120 and the display screen 100, the overall system's virtual-real confocal optical design cannot be achieved. Furthermore, when the user has visual impairments (myopia or hyperopia), additional devices are required to clearly see the image on the display device. Therefore, this embodiment introduces the diopter compensation lens 160 to provide a focal length adjustment channel, adjusting the focal length of the diopter compensation lens 160 according to the user's vision, thereby allowing the user to see a fused virtual-real image without wearing additional devices. This embodiment introduces a virtual image adjustment module 110, a real image adjustment module 120, and a diopter compensation lens 160 as the core of light field modulation, and constructs a near-eye display system with diopter compensation, large depth of field, and virtual-real fusion, which has good feasibility and scalability.

[0068] Example 4

[0069] This invention provides a method for viewing a large depth-of-field light field near-eye display based on polarization multiplexing. The method utilizes the aforementioned near-eye display device for implementing a large depth-of-field light field based on polarization multiplexing. The specific method is as follows: Figure 8 As shown, the method includes the following steps:

[0070] Step 1: The main controller first performs depth segmentation on the 3D scene to be displayed through the light field image acquisition program, dividing it into two depth planes; then, by setting up two sets of equally spaced virtual camera arrays in the light field image acquisition program and combining the optical structure of two sets of polarized flat microlens arrays, the focal length of the two sets of virtual cameras is adjusted to match the two depths of the 3D image, and finally light field image 1 and light field image 2 with different display depths are obtained.

[0071] Step 2: The main controller controls the display screen to show light field image 1 and controls the output voltage of the drive module;

[0072] Step 3: The first driving module controls the virtual image adjustment module to state 1. At this time, the driving module adjusts the input voltage of the first fast polarization modulator to modulate the polarization direction of the linearly polarized light to -45°. The first 1 / 4 wave plate modulates the -45° linearly polarized light into left-hand circularly polarized light. Finally, the first polarizing plate microlens array focuses the light at -f. At the same time, the second driving module controls the real image adjustment module to state 2. At this time, the driving module adjusts the input voltage of the second fast polarization modulator to modulate the polarization direction of the linearly polarized light to +45°. The second 1 / 4 wave plate modulates the +45° linearly polarized light into left-hand circularly polarized light. Finally, the second polarizing plate microlens array focuses the light at +f.

[0073] Step 4: The main controller switches the display screen to show light field image 2 and controls the output voltage of the drive module;

[0074] Step 5: The first driving module controls the virtual image adjustment module to be in state 2. At this time, the first driving module adjusts the input voltage of the fast polarization modulator to modulate the polarization direction of the first linearly polarized light to +45°. The first 1 / 4 wave plate modulates the +45° linearly polarized light into left-hand circularly polarized light. Finally, the first polarizing plate microlens array focuses the light at +f. At the same time, the second driving module controls the real image adjustment module to be in state 1. At this time, the second driving module adjusts the input voltage of the second fast polarization modulator to modulate the polarization direction of the linearly polarized light to -45°. The second 1 / 4 wave plate modulates the -45° linearly polarized light into left-hand circularly polarized light. Finally, the second polarizing plate microlens array focuses the light at -f.

[0075] Step 6: Determine whether to continue viewing. If to continue, switch to displaying light field image 1 and synchronously control the drive module; if not to continue, end the display process.

Claims

1. A polarization multiplexing based large depth of field light field near-eye display device, characterized in that, The application relates to a virtual-real image display device, which comprises the following components: a display screen (100) adopting a transparent LED, OLED or MicroLED display panel and used for providing a three-dimensional display virtual light field image source, a signal input end of the display screen being connected with a total controller (130) and being capable of realizing display and quick switching of the light field image; a virtual image adjusting module (110) arranged on an out-light side of the display screen (100) and comprising a first linear polarizer (1101), a first fast polarization modulator (1102), a first 1 / 4 wave plate (1103) and a first polarization flat micro-lens array (1104) arranged in sequence; a real image adjusting module (120) arranged on a non-out-light side of the display screen (100) and comprising a second linear polarizer (1201), a second fast polarization modulator (1202), a second 1 / 4 wave plate (1203) and a second polarization flat micro-lens array (1204) arranged in sequence; a total controller (130) used for generating a multi-depth light field image and controlling the display screen (100) and a driving module; a driving module composed of a first driving module (140) and a second driving module (141) and connected with the first fast polarization modulator (1102) and the second fast polarization modulator (1202) respectively, and used for adjusting focal lengths of the virtual image adjusting module (110) and the real image adjusting module (120) according to an instruction of the total controller (130); wherein the first driving module (140) and the second driving module (141) are configured to control the first polarization flat micro-lens array (1104) and the second polarization flat micro-lens array (1204) to have equal size and opposite sign of focal length by controlling the first fast polarization modulator (1102) and the second fast polarization modulator (1202) to keep a phase difference of 90 DEG, so that the virtual image adjusting module (110) and the real image adjusting module (120) jointly form a zero-power optical system, and virtual images and real world light rays are imaged at a design distance.

2. The polarization multiplexing based large depth of field light field near- eye display device of claim 1, wherein, The virtual image adjusting module (110) and the real image adjusting module (120) are respectively close to two side surfaces of the display screen (100), and satisfy 1 / f 1,2 =1 / f1+1 / f2-d 12 / f1f2, wherein f1 and f2 are focal lengths of the first polarizing plate microlens array (1104) and the second polarizing plate microlens array (1204) respectively, d 12 is a distance between the first polarizing plate microlens array (1104) and the second polarizing plate microlens array (1204), and d 12 ≈0, f1=-f2, and f 1,2 ≈∞.

3. The polarization multiplexing based large depth of field light field near- eye display device of claim 1, wherein, When the virtual image adjusting module (110) and the real image adjusting module (120) are arranged on the out-light side and the non-out-light side of the display screen (100) respectively, i.e. when there is a non-zero interval between the first polarization flat micro-lens array (1104) and the second polarization flat micro-lens array (1204), the device further comprises a power compensation lens (150) arranged in an optical path between the virtual image adjusting module (110) and the real image adjusting module (120), an optical axis of the power compensation lens being coincident with a normal line of the display screen (100) and being used for compensating power, wherein the power is the reciprocal of the focal length and satisfies the following formula: 1 / f 1,2,3 = 1 / f1 + 1 / f2 + 1 / f3 - d 12 / f1f2 - d 13 / f1f3 - d 23 / f2f3 + d 12 d 23 / f1f2f3 where f1, f2 and f3 are focal lengths of the first polarizing plate microlens array (1104), the second polarizing plate microlens array (1204) and the power compensation lens (150), respectively, d 12 is a pitch of the first polarizing plate microlens array (1104) and the second polarizing plate microlens array (1204), d 13 is a pitch of the second polarizing plate microlens array (1204) and the power compensation lens (150), d 23 is a pitch of the first polarizing plate microlens array (1104) and the power compensation lens (150), and f 1,2，3 ≈∞.

4. The polarization multiplexing based large depth of field light field near- eye display device of claim 1, wherein, The virtual image adjusting module (110) and the real image adjusting module (120) are arranged on the light-out side and the non-light-out side of the display screen (100) respectively, that is, when there is a non-zero spacing between the first polarizing flat micro-lens array (1104) and the second polarizing flat micro-lens array (1204), a diopter compensation lens (160) is further arranged for adjusting the imaging distance according to the vision condition of the user, so that the myopic or hyperopic user can clearly observe the virtual-real fused image without wearing an additional correction device.

5. The polarization multiplexing based large depth of field light field near-eye display device of claim 4, wherein, The diopter compensation lens (160) is arranged on the side close to the human eye through a slidable support, and the diopter adjustment range thereof is -6D~+3D, and the position thereof can be adjusted along the optical axis direction according to the vision condition of the user.

6. The polarization multiplexing based large depth of field light field near-eye display device of any one of claims 1-4, wherein, The total controller (130) acquires the multi-depth light field image through a light field image acquisition program, and the control signal output end thereof is connected with the display screen (100) and the driving module, so as to control the display and switching of the parallax image and the output voltage of the driving device.

7. The polarization multiplexing based large depth of field light field near- eye display device of claim 6, wherein, In the process of synchronously controlling the light field image switching and the output voltage of the driving module by the total controller (130), the light field image and the virtual image adjusting module and the real image adjusting module have a one-to-one matching relationship: when the display screen (100) displays the light field image 1, the first driving module (140) controls the fast polarization modulator (1102) of the virtual image adjusting module (110) to output linearly polarized light with a polarization direction of -45°, and controls the fast polarization modulator (1202) of the real image adjusting module (120) to output linearly polarized light with a polarization direction of +45°; when the display screen (100) displays the light field image 2, the second driving module (141) controls the first fast polarization modulator (1102) of the virtual image adjusting module (110) to output linearly polarized light with a polarization direction of +45°, and controls the first fast polarization modulator (1202) of the real image adjusting module (120) to output linearly polarized light with a polarization direction of -45°.

8. The polarization multiplexing based large depth of field light field near-eye display device of any one of claims 1-4, wherein, The driving module is a voltage adjusting device, which can synchronously control the output voltage to adjust the focal length of the virtual image adjusting module (110) and the real image adjusting module (120) according to the light field image information, so that the equivalent optical power of the near-eye three-dimensional display device is zero.

9. The polarization multiplexing based large depth of field light field near-eye display device of any one of claims 1-4, wherein, The first polarizing flat micro-lens array (1104) and the second polarizing flat micro-lens array (1204) each contain i x j periodically arranged sub-lens units, wherein i and j are the row and column numbers respectively, each sub-lens unit of the first polarizing flat micro-lens array (1104) corresponds to a sub-image area of the corresponding light field image in the display screen (100) one by one, so as to realize light field modulation, and after all the sub-images pass through the first polarizing flat micro-lens array (1104), a three-dimensional light field display effect will be presented; The image of the real world is modulated by the first polarizing flat micro-lens array (1104) and the second polarizing flat micro-lens array (1204) in double layers, and the real environment image is superimposed into the field of view of the human eye.

10. A method of a large depth of field light field near-eye display based on polarization multiplexing, using the device of any one of claims 1-9, characterized in that, The method comprises the following steps: The first step: the total controller obtains the light field image 1 and the light field image 2 of different display depths through a light field image acquisition program; The second step: the total controller controls the display screen to display the light field image 1, and controls the output voltage of the driving module; The third step: the first driving module controls the virtual image adjusting module to be in state 1, and the second driving module controls the real image adjusting module to be in state 2; The fourth step: the total controller switches the display screen to display the light field image 2, and controls the output voltage of the driving module; The fifth step: the first driving module controls the virtual image adjusting module to be in state 2, and the second driving module controls the real image adjusting module to be in state 1; The sixth step: the second step to the fifth step are repeated to realize the continuous display of the multi-depth light field.

11. The polarization multiplexing based large depth of field light field near-eye display device method of claim 10, wherein, The state 1 is that the fast polarization modulator outputs-45° linearly polarized light, which is converted into left circularly polarized light through a 1 / 4 wave plate, and the polarization flat micro-lens array is focused at-f; the state 2 is that the fast polarization modulator outputs+45° linearly polarized light, which is converted into right circularly polarized light through a 1 / 4 wave plate, and the polarization flat micro-lens array is focused at+f.

Images