Light field modulation device, display system and light field modulation method

Abstract

The invention provides a light field modulation device, a display system and a light field modulation method. In one aspect, the light field modulation device includes: a substrate having a first direction and a second direction orthogonal to the first direction, the substrate configured to deform under physical excitation; the nano-structure array is arranged on one side of the substrate, the nano-structure array comprises a plurality of nano-structure units, and the plurality of nano-structure units are arranged in a first direction according to a preset period; and the driving device is arranged on the substrate, the driving device is configured to apply physical excitation to the substrate, and the deformation of the substrate under the physical excitation enables the preset period to change in the first direction so as to change the phase gradient of the light penetrating through the nanostructure array. Therefore, active dynamic control over light field deflection is achieved, and the display effect and the viewing freedom degree of the naked eye 3D image are improved.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and more specifically, to a light field modulation device, a display system, and a light field modulation method. Background Technology

[0002] With the development of display technology, the requirements for visual experience are becoming increasingly demanding. 3D display technology has attracted much attention because it can provide realistic images with depth information. Naked-eye 3D display technology allows viewers to perceive stereoscopic images without the need for special glasses or helmets, thus it has broad application prospects in fields such as smartphones, tablets, laptops, automotive displays, professional monitors, and augmented reality (AR) near-eye display systems.

[0003] The glasses-free 3D display technology typically employs parallax barriers or lenticular lens technology. The basic principle of these technologies is to place a static physical structure, such as a grating or lens array, in front of the display panel. This projects the light emitted by different pixels of the display panel onto different areas in space, allowing the viewer's left and right eyes to receive parallax images separately, which are then synthesized into a 3D image in the brain.

[0004] However, this naked-eye 3D display technology based on static physical structures offers a narrow viewing range. The display effect will decrease if the viewer moves their head slightly, and the freedom of viewing is severely limited. Summary of the Invention

[0005] This section provides a general overview of this disclosure, rather than a full disclosure of the entire scope or all features of this disclosure.

[0006] According to one aspect of this disclosure, an optical field modulation device is provided. The optical field modulation device includes a substrate, a nanostructure array, and a driving device. The substrate has a first direction and a second direction orthogonal to the first direction, and is configured to deform under physical excitation. The nanostructure array is disposed on one side of the substrate, and includes a plurality of nanostructure units arranged at a predetermined period in the first direction. The driving device is disposed on the substrate and is configured to apply a physical excitation to the substrate, the deformation of the substrate under the physical excitation causing the predetermined period to change in the first direction, thereby altering the phase gradient of light transmitted through the nanostructure array.

[0007] According to another aspect of this disclosure, a display system is provided. The display system includes a display panel, the aforementioned light field modulation device, and a controller. The display panel is used to provide image light. The light field modulation device is disposed on the light-emitting side of the display panel. The controller is communicatively connected to the light field modulation device and is used to send control signals to the light field modulation device to adjust the intensity of the physical excitation.

[0008] According to another aspect of this disclosure, a light field modulation method is provided. This light field modulation method is applied to the aforementioned display system. The light field modulation method includes: calculating a target beam deflection angle corresponding to each pixel unit of the display panel based on the position of the target parallax point; determining a target intensity of the physical excitation required to achieve the target beam deflection angle based on a predetermined correspondence between physical excitation intensity and deflection angle; and controlling a driving device of the light field modulation apparatus to apply a physical excitation of the target intensity to a substrate to change a preset period of the nanostructure array in a first direction, thereby deflecting the image light provided by the display panel at the target beam deflection angle. Attached Figure Description

[0009] The features and advantages of embodiments of the present disclosure will become more readily understood from the following description with reference to the accompanying drawings. The drawings are not drawn to scale and some features may be enlarged or reduced to show details of specific components. In the drawings:

[0010] Figure 1 This is a top view of a light field modulation apparatus according to an embodiment of the present disclosure.

[0011] Figure 2 for Figure 1 The front view of the light field modulation device shown.

[0012] Figure 3 for Figure 1 The diagram shows the anisotropic response principle of the optical field modulation device at different temperatures.

[0013] Figure 4 This is a schematic diagram of a display system according to an embodiment of the present disclosure.

[0014] Figure 5 for Figure 4 The diagram shows the optical path and dynamic parallax formation of the display system in 3D working mode.

[0015] Figure 6 This is a schematic diagram of a display system according to another embodiment of the present disclosure.

[0016] Figure 7 for Figure 6 The diagram shows the optical path and zero-deflection state of the display system in 2D working mode.

[0017] Figure 8 This is a schematic flowchart of an optical field modulation method according to an embodiment of the present disclosure.

[0018] In the accompanying drawings, the same or corresponding technical features or components are represented by the same or corresponding reference numerals. Detailed Implementation

[0019] The present disclosure will now be described in detail with reference to the accompanying drawings and exemplary embodiments. It should be noted that the following detailed description of the present disclosure is for illustrative purposes only and is not intended to limit the scope of the disclosure.

[0020] It should be noted that, for clarity, not all features of a particular embodiment are described or shown in the specification and drawings. Furthermore, to avoid unnecessary details obscuring the technical solutions of interest in this disclosure, only the device structure closely related to the technical solutions of this disclosure is described and shown in the specification and drawings, while other details that are not closely related to the technical content of this disclosure and are known to those skilled in the art are omitted.

[0021] Before delving into the technical solutions disclosed herein, we will first provide a more detailed explanation of the problems faced by related glasses-free 3D display technologies.

[0022] Current glasses-free 3D display technologies, especially those based on fixed lenticular lens arrays or parallax barriers, essentially rely on static physical structures. While these static physical structures can achieve basic stereoscopic display functions, their inherent limitations restrict the display effect and user experience.

[0023] Because the physical curvature and focal length of a cylindrical lens are fixed, the resulting parallax angle and optimal viewing distance cannot be changed once designed. This results in a very narrow viewing "sweet spot." Viewers must keep their heads in a specific position; even slight movement will cause misalignment of the images for the left and right eyes, leading to 3D image crosstalk or loss of stereoscopic effect, affecting the display quality and limiting viewing freedom.

[0024] In response, according to embodiments of this disclosure, an optical field modulation device is provided. This optical field modulation device can actively and dynamically reshape the wavefront of transmitted light, thereby achieving precise control of the beam propagation direction.

[0025] Below, refer to Figure 1 and Figure 2 The optical field modulation device 100 is described in detail.

[0026] The optical field modulation device 100 includes a substrate 120, a nanostructure array 140, and a driving device 160.

[0027] It should be noted that, for ease of description and understanding, this embodiment first defines a local coordinate system within the plane containing the base 120. For example... Figure 1As shown, a first direction (X-axis direction) is defined as the expected beam deflection and modulation direction, and a second direction (Y-axis direction) orthogonal to the first direction is defined as the unmodulated or weakly modulated direction. In typical applications of this embodiment (such as naked-eye 3D display), the first direction usually corresponds to the direction of the line connecting the viewer's eyes (i.e., the horizontal parallax direction), while the second direction corresponds to the vertical direction.

[0028] The substrate 120 is not a rigid glass or plastic sheet that merely serves a supporting function as in traditional optical devices, but rather an "actuation medium" configured to deform under physical excitation to achieve dynamic control functions. In this case, the substrate 120 can be made of a material with a specific elastic modulus that is sensitive to external physical fields (such as thermal, electric, or magnetic fields). Upon receiving an external energy input, the substrate 120 can undergo macroscopic geometric deformation, such as expansion or contraction of volume.

[0029] A nanostructure array 140 is disposed on one side of the substrate 120. The nanostructure array 140 includes a plurality of tiny nanostructure units 142. These nanostructure units 142 are not randomly distributed, but are precisely calculated and arranged with a predetermined period P in a first direction.

[0030] like Figure 1 and Figure 2 As shown, the preset period P refers to the center-to-center distance between two adjacent nanostructure units 142 in the first direction in the initial state without physical excitation. The geometric dimensions of these nanostructure units 142 are typically on the subwavelength scale, thus optically constituting a metasurface capable of abruptly controlling the phase of light waves. Here, a metasurface refers to a planar optical element composed of a subwavelength-scale array of micro- and nanostructures, which can control the wavefront of electromagnetic waves (light waves) by introducing phase abrupt changes, thereby achieving functions such as beam deflection and focusing.

[0031] A drive device 160 is disposed on a substrate 120. The drive device 160 is configured to apply a physical excitation to the substrate 120, thereby actively inducing a change in the physical state of the substrate 120.

[0032] The dynamic optical field modulation achieved by the optical field modulation device 100 is based on the deep coupling between the "generalized Snell's law" and "material mechanics". Specifically, when the driving device 160 is activated and applies physical excitation to the substrate 120, the substrate 120 absorbs energy, which in turn causes macroscopic deformation of the substrate 120. Since the nanostructure unit 142 is disposed (e.g., physically attached) on the surface of the substrate 120, the expansion and contraction deformation of the substrate 120 in the first direction directly causes the nanostructure unit 142 to undergo relative displacement. This displacement causes a change in the preset period P of the nanostructure array 140 in the first direction.

[0033] According to the principle of metasurface phase modulation, the wavefront deflection angle of the transmitted beam mainly depends on the phase gradient introduced by the interface. For periodically arranged metasurfaces, the phase gradient is inversely proportional to the period of the structure. Therefore, when physical excitation causes a change in the period P in the first direction, the phase gradient of the light transmitted through the nanostructure array 140 also changes, thereby tilting the wavefront of the emitted beam, that is, changing the deflection angle of the emitted beam in the first direction.

[0034] In this way, precise "programming" of the deflection angle of the emitted light beam in the first direction is achieved, that is, active dynamic control of the light field deflection is realized. Unlike naked-eye 3D display methods based on static physical structures in related technologies, this embodiment can adjust the deflection angle of the light beam by adjusting the intensity of the physical excitation and changing the period of the nanostructure array 140 in real time. As a result, viewers no longer need to keep their heads in a specific narrow position to see clear 3D images. Instead, the viewing area can be dynamically generated, moved, and optimized according to the viewer's position, allowing the head to see clear 3D images over a wider range, thereby improving the display effect of 3D images and increasing the degree of freedom of viewing.

[0035] In some embodiments, the physical excitation can be thermal excitation. Accordingly, the specific hardware form of the drive device 160 can be a heating element. The heating element can be integrated on the outer surface or inside the substrate 120 for regulating the temperature of the substrate 120.

[0036] Specifically, when the heating element is energized, it converts electrical energy into heat energy through the resistance heating effect. The heat is conducted to the substrate 120, causing the temperature of the substrate 120 to rise, which in turn causes the substrate 120 to deform. Moreover, it is understandable that the magnitude of the deformation will vary depending on the temperature at which the substrate 120 is heated.

[0037] Reference Figure 3 This illustrates a schematic diagram of the anisotropic response principle of the optical field modulation device 100 at different temperatures. Figure 3 The image shows a display panel 200, which will be described below, including a first pixel A1 and a second pixel A2, and each pixel has a light field modulation device 100 on its light-emitting side.

[0038] like Figure 3 As shown on the left, when the substrate 120 of the light field modulation device 100 corresponding to the first pixel A1 and the second pixel A2 is uniformly heated to the same temperature, the substrate 120 undergoes the same deformation in the first direction, causing the light beams S1 and S2 emitted from the first pixel A1 and the second pixel A2 to produce the same deflection angle θ0 in the horizontal plane after passing through the corresponding light field modulation device 100.

[0039] On the other hand, such as Figure 3 As shown on the right, when the substrates 120 of the light field modulation devices 100 corresponding to the first pixel A1 and the second pixel A2 are uniformly heated to different temperatures, the two substrates 120 undergo different deformations in the first direction, causing the light beams S1 and S2 emitted from the first pixel A1 and the second pixel A2 to produce different deflection angles in the horizontal plane after passing through the corresponding light field modulation devices 100.

[0040] Specifically, the substrate 120 of the light field modulation device 100 corresponding to the first pixel A1 is heated to temperature T1, and the substrate 120 of the light field modulation device 100 corresponding to the second pixel A2 is heated to temperature T2, where T1 is greater than T2. ​​As a result, the deformation of the substrate 120 corresponding to the first pixel A1 in the first direction is greater than the deformation of the substrate 120 corresponding to the second pixel A2 in the first direction, and consequently, the period of the corresponding nanostructure array 140 in the first direction is larger. This results in the beam S1 deflection angle θ1 in the horizontal plane being smaller than the beam S2 deflection angle θ2 in the horizontal plane after passing through the corresponding light field modulation device 100.

[0041] Since temperature is a scalar physical quantity and can be finely adjusted by controlling the input power (current or voltage) of the heating element, the deformation of the substrate 120 and thus the periodic changes are continuous and smooth. Precise temperature control allows for precise fine-tuning of the beam deflection angle, thereby reducing the complexity of the control algorithm and hardware, and eliminating the abrupt changes during viewpoint switching.

[0042] It is conceivable that the heating element could be a transparent conductive film of indium tin oxide (ITO).

[0043] It is also conceivable that the heating element can be directly fabricated below the light field adjustment device 100 using mature semiconductor processes (such as sputtering and photolithography).

[0044] In this way, compared to mechanical actuation schemes that require complex linkages, motors, etc., the thickness of the resulting optical field modulation device 100 can be only at the nanometer level. As a result, the entire optical modulation device 100 can be very flat and thin, making it easy to bond and integrate with existing flat panel display panels, and thus better meeting the stringent requirements for thinness and lightness in consumer electronics products.

[0045] It is conceivable that the drive unit 160 may also include a temperature sensor to adjust the heating temperature of the heating element in real time by sensing the temperature of the substrate 120, thereby achieving more precise temperature control.

[0046] In some implementations, such as Figure 1 and Figure 2 As shown, the nanostructure unit 142 is designed as an asymmetric structure, and the size of the nanostructure unit 142 in the second direction (Y-axis direction) is larger than its size in the first direction (X-axis direction).

[0047] like Figure 1 As shown in the top view, this nanostructure unit 142 presents as a slender strip, ellipse, ridge, or line structure. In the field of physical optics, this structure is often referred to as a "nanofindigo fin" and can be fabricated using techniques such as nanoimprint lithography.

[0048] The stiffness distribution of slender structures is non-uniform. Typically, the tensile stiffness along the major axis (second direction) is higher than that along the minor axis (first direction). That is, when the slender structure is heated by a uniform thermal field, the dimensional change along the minor axis will be greater than the dimensional change along the major axis.

[0049] In this way, the light field modulation device 100 can generate large-amplitude periodic changes and beam deflection in the first direction (i.e., the horizontal parallax direction), while maintaining relative stability of the structure and optical path in the second direction (vertical direction). This is crucial for glasses-free 3D displays, because human stereoscopic vision mainly relies on horizontal parallax, and introducing unnecessary deflection in the vertical direction is not only unhelpful but can also lead to image distortion and viewing dizziness.

[0050] When the nanostructure unit 142 is a nanofin, it is conceivable that the substrate 120 can have an isotropic coefficient of thermal expansion, and the deformation of the substrate 120 under thermal excitation causes the gap between adjacent nanofins to change.

[0051] The term "isotropy" means that the coefficient of thermal expansion of the substrate 120 is the same in all directions. When the substrate 120 is heated, due to the isotropy of its material, it instinctively tends to expand simultaneously in the first and second directions.

[0052] In the first direction, there are physical gaps between adjacent nanofins. Since the nanofins are attached to the substrate 120, the expansion of the substrate 120 in the first direction directly stretches these gap regions. Because the period P of the nanostructure array 140 is equal to the width of the nanofins plus the width of the gaps, and the nanofins themselves are usually made of rigid materials and are relatively resistant to deformation, the expansion of the substrate 120 is almost entirely converted into an increase in the gap width. This increase in gaps directly leads to an increase in the period P.

[0053] In the second direction, the nanofins can be continuous lines running through the entire metasurface unit, or discrete rectangular chains with a length much greater than their width. Since the Young's modulus of the nanofin material is greater than that of the substrate 120 material, the nanofins exert a confinement effect on the substrate 120 in the second direction, suppressing its expansion. In other words, even if the substrate 120 experiences a slight elongation in the second direction, because the nanofins are long waveguides in this direction, the minute change in their length will not alter their phase modulation characteristics of light.

[0054] In this way, isotropic thermal excitation is converted into directional, programmable horizontal beam deflection. Moreover, it allows the use of common optical polymers with mature and inexpensive fabrication processes as substrates, and through the geometric design of surface micro- and nanostructures, the function of adjusting parallax only in the horizontal direction can be achieved, thereby reducing manufacturing costs.

[0055] In some embodiments, the substrate 120 may also have an anisotropic coefficient of thermal expansion, and the substrate 120 may be configured to produce greater deformation in a first direction than in a second direction under thermal excitation.

[0056] For example, the substrate 120 may be subject to special physical or chemical treatment (e.g., a pre-stretched oriented polymer) to obtain an anisotropic coefficient of thermal expansion.

[0057] In this case, regardless of the shape of the nanostructure on the substrate 120, such as even a cylindrical symmetrical structure, the deformation of the substrate 120 in the first direction will dominate the change of the period of the nanostructure array 140, thereby changing the phase gradient.

[0058] In this way, the design of the nanostructure unit 142 is no longer limited to being elongated, but can be freely chosen to be symmetrical structures such as cylinders and squares. This helps to optimize light extraction efficiency, reduce polarization sensitivity, and provides greater freedom for the overall optimization of the optical system.

[0059] In the case that the nanostructure unit 142 is a symmetrical structure, it is also conceivable that the driving device 160 includes a heating element with an oriented shape, which is configured to generate a directional thermal conduction field to induce directional deformation of the substrate 120 in a first direction.

[0060] For example, the heating element can be designed as a thin resistance wire or strip arranged parallel to the second direction. When the thin heat source heats up, the heat flow mainly diffuses along a gradient perpendicular to the direction of extension of the heat source (i.e., the first direction), thereby forming a significant temperature gradient within the substrate 120. Since the degree of thermal expansion of the material directly depends on the local temperature, the directional temperature distribution causes the substrate 120 to generate greater thermal stress and deformation mainly in the first direction, while the temperature distribution in the second direction is relatively uniform or restricted, resulting in smaller deformation.

[0061] In this way, neither specially prepared anisotropic materials nor complex asymmetric nanostructures are required; the light field can be controlled simply by changing the design of the heating element.

[0062] It is conceivable that the substrate 120 could be made of a flexible polymer material with a specific coefficient of thermal expansion. This would ensure high transmittance of the optical field modulation device 100 in the visible light band and sufficient mechanical deformation at low energy input.

[0063] For example, the substrate 120 can be made of polydimethylsiloxane (PDMS). PDMS not only has excellent optical transparency (typically exceeding 90% transmittance in the visible spectrum) to minimize light energy loss, but also has a high coefficient of thermal expansion and good resilience. These material properties allow the substrate 120 to reversibly expand or contract its macroscopic volume when receiving physical stimuli (such as heat), and to quickly return to its initial state after the stimuli are removed, thereby ensuring the repetitive lifespan and response speed of the optical field modulation device 100.

[0064] Furthermore, the nanostructure unit 142 can be made of a high-refractive-index, low-loss dielectric material to ensure strong interaction with light waves and high transmission efficiency. It is conceivable that the nanostructure unit 142 can be made of at least one of silicon nitride (Si3N4), titanium dioxide (TiO2), and gallium nitride (GaN). These materials have good process compatibility with the substrate 120 fabricated using a flexible polymer material.

[0065] In some implementations, such as Figure 2 As shown, the height H of the nanostructure unit 142 can be 400~800nm, and the width W in the first direction can be 50~150nm.

[0066] The height range of 400~800nm ​​was optimized through simulation, enabling the nanostructure unit 142 to act as a local waveguide and provide a complete phase modulation range covering 0~2π for transmitted light in the visible light band.

[0067] The width of 50~150nm is much smaller than the wavelength of visible light (400~700nm). This ensures that the nanostructure unit 142 is in the subwavelength diffraction region, avoiding energy loss at high diffraction orders.

[0068] Furthermore, in some embodiments, the period P can be continuously varied within the operating temperature range (e.g., 25~80°C) in the range of, for example, 250~450 nm, thereby enabling continuous scanning of the emitted beam angle.

[0069] Furthermore, it is conceivable that within a single light field modulation device 100 (i.e., a single metasurface unit, corresponding to one or a group of pixels in the display panel), tens to hundreds of nanofins are arranged with a constant preset period P to form a one-dimensional grating. The entire display panel is then composed of millions of such metasurface units tightly joined together.

[0070] It is conceivable that the driving device 160 may include multiple independently controllable heating elements, each heating element corresponding to one or a group of nanostructure units 142 of the nanostructure array 140, that is, corresponding to one pixel or a group of pixels of the display panel.

[0071] In this way, by applying different currents or voltages to these different heating elements, a complex and non-uniform temperature field distribution can be established on the surface of the substrate 120. Since the local deformation of the substrate 120 depends on the local temperature, this means that metasurface regions at different locations on the display panel can simultaneously have completely different periods. For example, the period of the left side of the display panel increases to deflect light to the right, while the period of the right side of the display panel decreases to deflect light to the left.

[0072] This allows light from different positions on the display panel to be precisely focused onto the viewer's left or right eye, thereby eliminating parallax image distortion and enabling better dynamic construction, movement, and optimization of the 3D viewing area.

[0073] In another aspect, according to embodiments of this disclosure, a display system is also provided. Referring hereafter... Figure 4 The display system 10 will be described in detail.

[0074] The display system 10 includes a light field modulation device 100, a display panel 200, and a controller 300.

[0075] The display panel 200 serves as an image source, providing image light that carries image information. In some embodiments, the display panel 200 may be a micro-LED pixel array. However, it is also conceivable that the display panel 200 may be other types of display panels such as an organic light-emitting diode (OLED) display or a liquid crystal display (LCD).

[0076] The light field modulation device 100 is disposed on the light-emitting side of the display panel 200. For example, the light field modulation device 100 can be attached to the display panel 200. The light field modulation device 100 is used to perform phase modulation on the image light emitted from the display panel 200 to change the propagation direction of the image light.

[0077] The controller 300 is communicatively connected to the optical field modulation device 100 and is used to send control signals to the optical field modulation device 100 to adjust the intensity of the physical excitation applied to the substrate 120. In a specific hardware implementation, the controller 300 may include a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC) chip.

[0078] Specifically, the controller 300 can first calculate the light field distribution strategy according to the display requirements; then, it sends a driving command to the optical modulation device 100 through the communication interface; the driving device 160 converts the electrical signal into heat energy (physical excitation); the substrate 120 undergoes microscopic deformation due to heat, changing the period of the nanostructure array 140; finally, the image light emitted from the display panel 200 undergoes the expected deflection of its wavefront when passing through the deformed nanostructure array 140.

[0079] In this way, the direction of the light field can be controlled by a controller, thus providing a hardware foundation for better adaptive, ghosting-free 3D display.

[0080] The working modes of the display system 10 will be described in detail below.

[0081] First, in the case of 3D display, such as Figure 5 As shown, controller 300 can be configured to execute a first operating mode. In this first operating mode, controller 300 executes the following closed-loop logic: Based on the position of the target parallax point, i.e. the spatial coordinates of the viewer's eye 20, the angle required to deflect the light emitted from each pixel unit of the display panel 200 is calculated as the corresponding target beam deflection angle. Based on a predetermined relationship between physical excitation intensity and deflection angle, such as through pre-calibration or modeling, the target intensity of the physical excitation required to achieve the target beam deflection angle is determined, for example, the target temperature; and A control signal is sent to the light field modulation device 100 to control the driving device 160 to apply a target intensity physical excitation to the substrate 120 to form a parallax image pointing to the target parallax point.

[0082] In this way, regardless of how the viewer moves their head, the display system 10 can calculate and adjust the direction of light in real time, ensuring that the 3D image always follows the viewer's eyes. This completely solves the problem of users having to maintain a rigid posture and find a specific viewing position in traditional glasses-free 3D technology.

[0083] It is conceivable that, with reference to Figure 6The display system 10 may also include an eye-tracking sensor 400.

[0084] The eye-tracking sensor 400 is used to detect the viewer's eye position in real time. The controller 300 is connected in communication with the eye-tracking sensor 400 to update the position of the target parallax point in real time based on the eye position data provided by the eye-tracking sensor 400, so as to dynamically adjust the intensity of the physical stimulus applied to the substrate 120.

[0085] Specifically, the eye-tracking sensor 400 can capture facial images at a high frame rate and calculate the three-dimensional coordinates of both eyes through image processing algorithms (such as feature point extraction). With the light field modulation device 100 based on thermal actuation, the display system 10 can complete the entire process from updating the target parallax point position to reconstructing the light field in a very short time.

[0086] In this way, when viewers move their heads to observe 3D objects, they can see the correct binocular parallax and see different images of the object's side as the viewing angle changes. This greatly enhances the realism and immersion of the virtual image, while also alleviating or even resolving the vergence-accommodation conflict (VAC), thereby alleviating or even eliminating visual fatigue, dizziness, nausea, and other discomforts caused by VAC.

[0087] For glasses-free 3D display technologies based on static physical structures, the lenticular lens array covering the display panel cannot be physically removed when displaying two-dimensional (2D) content (such as text, web pages, or ordinary videos). These microlens structures continuously modulate the light emitted by the pixels, leading to a decrease in image sharpness. Simultaneously, interference effects between the lens array and the pixel array can easily produce moiré patterns, and parallax barrier technology can directly cause a loss of brightness.

[0088] In this regard, refer to Figure 7 The controller 300 can also be configured to execute a second operating mode. In the second operating mode, the controller 300 applies a reference control signal to the light field modulation device 100 or stops applying the control signal, so that the light field modulation device 100 is in a zero-deflection state, allowing the image light of the display panel 200 to be transmitted without deflection to display a 2D image.

[0089] For example, when heating stops, the substrate 120 rapidly dissipates heat to the surrounding environment. Due to the excellent elasticity of materials such as PDMS, the substrate 120 releases its stored elastic energy during cooling, precisely reverting the deformation that occurred during heating and returning the substrate 120 to its initial state. The period of the nanostructure array 140 can be set such that the phase gradient is zero in the initial state, thereby placing the light field modulation device 100 in a zero-deflection state. Thus, the light field modulation device 100 is substantially transparent to light, allowing the image light from the display panel 200 to be transmitted without deflection to display a 2D image.

[0090] In this way, viewers can see the original high-resolution, high-brightness, and artifact-free image of the display panel 200. This makes the display system 10 a universal terminal capable of viewing both 3D images and high-definition, high-brightness, moiré-free 2D images.

[0091] In another aspect, according to embodiments of the present disclosure, a light field modulation method is also provided, which is applied to the above-described display system 10.

[0092] Reference Figure 8 The optical field modulation method includes the following steps: Step S210: Calculate the target beam deflection angle corresponding to each pixel unit of the display panel 200 based on the position of the target parallax point; Step S220: Based on the predetermined correspondence between physical excitation intensity and deflection angle, determine the target intensity of the physical excitation required to achieve the target beam deflection angle; and Step S230: Control the driving device 160 of the light field modulation device 100 to apply a physical excitation of target intensity to the substrate 120 to change the preset period of the nanostructure array 140 in the first direction, thereby deflecting the image light provided by the display panel 200 by the target beam deflection angle.

[0093] Although this disclosure has been described with reference to exemplary embodiments, it should be understood that this disclosure is not limited to the specific embodiments described and shown herein. Various changes can be made to the exemplary embodiments by those skilled in the art without departing from the scope defined by the claims of this disclosure.

[0094] The features mentioned and / or shown in the foregoing description of exemplary embodiments of this disclosure may be combined in the same or similar manner with one or more other embodiments, combined with features in other embodiments, or substituted for corresponding features in other embodiments. Such combinations or substitutions should also be considered as including within the scope of protection of this disclosure.

Claims

1. An optical field modulation device, characterized in that, include: A substrate having a first direction and a second direction orthogonal to the first direction, the substrate being configured to deform under physical excitation; A nanostructure array is disposed on one side of the substrate. The nanostructure array includes multiple nanostructure units, which are arranged in a predetermined period in the first direction. as well as A driving device is disposed on the substrate and configured to apply the physical excitation to the substrate, wherein the deformation of the substrate under the physical excitation causes the preset period to change in the first direction, thereby altering the phase gradient of light transmitted through the nanostructure array.

2. The optical field modulation device according to claim 1, characterized in that, The physical excitation is thermal excitation, and the driving device includes a heating element for adjusting the temperature of the substrate.

3. The optical field modulation device according to claim 2, characterized in that, The nanostructure unit is an asymmetric structure, and the size of the nanostructure unit in the second direction is larger than its size in the first direction.

4. The optical field modulation device according to claim 3, characterized in that, The nanostructure unit is a nanofin, and the substrate has an isotropic coefficient of thermal expansion. The deformation of the substrate under thermal excitation causes the gap between adjacent nanofins to change.

5. The optical field modulation device according to claim 2, characterized in that, The substrate has an anisotropic coefficient of thermal expansion, and the substrate is configured to produce a greater deformation in the first direction than in the second direction under the thermal excitation.

6. The optical field modulation device according to claim 2, characterized in that, The nanostructure unit is a symmetrical structure, and the driving device includes a heating element with an oriented shape, the heating element being configured to generate a directional thermal conduction field to induce directional deformation of the substrate in the first direction.

7. The optical field modulation device according to claim 1, characterized in that, The substrate is made of polydimethylsiloxane.

8. The optical field modulation device according to claim 1, characterized in that, The nanostructure unit is made of at least one of silicon nitride, titanium dioxide, and gallium nitride.

9. The optical field modulation device according to claim 1, characterized in that, The height of the nanostructure unit is 400~800nm, and the width in the first direction is 50~150nm.

10. The optical field modulation device according to claim 2, characterized in that, The driving device includes multiple independently controllable heating elements, each of which corresponds to one or a group of nanostructure units of the nanostructure array.

11. A display system, characterized in that, include: Display panel, used to provide light for the image; The light field modulation device according to any one of claims 1 to 10 is disposed on the light-emitting side of the display panel; as well as The controller is communicatively connected to the optical field modulation device and is used to send control signals to the optical field modulation device to adjust the intensity of the physical excitation.

12. The display system according to claim 11, characterized in that, The controller is configured to execute a first operating mode, in which the controller: Based on the position of the target parallax point, calculate the target beam deflection angle corresponding to each pixel unit of the display panel; Based on the predetermined relationship between physical excitation intensity and deflection angle, the target intensity of the physical excitation required to achieve the target beam deflection angle is determined; as well as The control signal is sent to the light field modulation device to control the driving device to apply the physical excitation of the target intensity to the substrate to form a parallax image pointing to the target parallax point.

13. The display system according to claim 12, characterized in that, It also includes an eye-tracking sensor for real-time detection of the viewer’s eye position. The controller is communicatively connected to the eye-tracking sensor to update the position of the target parallax point in real time based on the eye position data provided by the eye-tracking sensor.

14. The display system according to claim 12, characterized in that, The controller is also configured to execute a second operating mode, in which the controller: Applying a reference control signal to the light field modulation device or stopping the application of the control signal causes the light field modulation device to be in a zero-deflection state, so that the image light of the display panel can be transmitted without deflection to display a two-dimensional image.

15. A method for optical field modulation, characterized in that, The light field modulation method is applied to the display system according to any one of claims 11 to 14, the light field modulation method comprising: Based on the position of the target parallax point, calculate the target beam deflection angle corresponding to each pixel unit of the display panel; Based on the predetermined relationship between physical excitation intensity and deflection angle, the target intensity of the physical excitation required to achieve the target beam deflection angle is determined; and The driving device that controls the light field modulation device applies the physical excitation of the target intensity to the substrate to change the preset period of the nanostructure array in the first direction, thereby deflecting the image light provided by the display panel by the target beam deflection angle.

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