Optical engine, light-guiding device, and near-eye display device

Abstract

Provided in the embodiments of the present application are an optical engine, a light-guiding device, and a near-eye display device. The optical engine comprises: a micro display component, which is used for emitting image light; and a metasurface element, wherein the micro display component and the metasurface element are attached to each other in a light transmission direction, and the metasurface element is used for modulating the image light and coupling the modulated image light into a light-guiding device.

Description

An optical engine, a light guide device, and a near-eye display device Technical Field

[0001] This application relates to the field of optical display technology, and more specifically, to an optomechanism, a light guide device, and a near-eye display device. Background Technology

[0002] A waveguide is a medium that guides electromagnetic waves (including light waves) to propagate. In technologies such as AR and VR, waveguides are widely used to efficiently transmit image information to users. The working principle of a waveguide is primarily based on the physical phenomenon of total internal reflection. By designing a specific optical path, light is continuously reflected within the waveguide material, thereby enabling the transmission of optical signals.

[0003] In the field of near-eye displays, the optical signals that enter the waveguide for transmission typically originate from an optomechanical system. The application of optomechanics in near-eye displays, especially in optical devices such as AR glasses, involves complex optical design and component coordination.

[0004] Existing optomechanical systems (OMS) consist of light sources, optical components (such as lens systems), and mechanical structures, resulting in complex structures and large volumes. When OMS is combined with waveguides, the overall architecture becomes even larger.

[0005] In view of this, a new technical solution is needed to solve the above-mentioned technical problems.

[0006] Utility Model Content

[0007] The purpose of this application is to provide a new technology solution for an optical engine, a light guide device, and a near-eye display device.

[0008] In a first aspect, embodiments of this application provide an optical engine. The optical engine includes:

[0009] Miniature display components used to emit light for images;

[0010] A metasurface element is provided, wherein the microdisplay component and the metasurface element are attached together along the light transmission direction, and the metasurface element is used to modulate the image light and couple the modulated image light into the light guide device.

[0011] Optionally, the microdisplay component and the metasurface element are bonded together.

[0012] Optionally, the adhesive layer between the microdisplay component and the metasurface element is annular.

[0013] Optionally, the bonding air gap between the microdisplay component and the metasurface element is less than 1 μm.

[0014] Optionally, the microdisplay component includes a light source, wherein the light source is a collimated light source.

[0015] Optionally, the microdisplay component further includes a microdisplay chip disposed on the light emission path of the light source.

[0016] Optionally, the metasurface element is composed of subwavelength micro / nano structures, wherein each micro / nano structure in the metasurface element corresponds one-to-one with a pixel in the microdisplay component, and the micro / nano structure modulates and refracts the light emitted from its corresponding pixel into the light guide device.

[0017] Optionally, the metasurface element includes a dielectric layer formed by arranging a plurality of subwavelength-sized micro / nano structures along the light transmission direction. The dielectric layer is configured to modulate the image light and couple the modulated image light into the light guide device.

[0018] Optionally, the metasurface element includes a first part and a second part along the light transmission direction, and both the first part and the second part include a dielectric layer formed by the arrangement of multiple micro-nano structures of the subwavelength size;

[0019] The first part is configured to modulate the image light, and the second part is configured to couple the modulated image light into the light guide device.

[0020] Optionally, the subwavelength-sized micro / nanostructure includes any one or a combination of several of the following: nanoblocks, nanopillars, nanostrips, and irregular patterns.

[0021] Secondly, embodiments of this application also provide a light guide device. The light guide device includes the optomechanical system described in the first aspect.

[0022] Thirdly, embodiments of this application also provide a near-eye display device. The near-eye display device includes the light guide device as described in the second aspect.

[0023] According to embodiments of this application, the optical engine comprises only two parts: a microdisplay component and a metasurface element. Compared to existing optical engine structures, the optical engine structure is simpler and its size is reduced.

[0024] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0026] Figure 1 shows a schematic diagram of the structure of the optical engine provided in an embodiment of this application.

[0027] Figure 2 shows a schematic diagram of the optical path corresponding to a certain pixel in the optical engine provided in the embodiment of this application.

[0028] Figures 3a and 3b show schematic diagrams of the metasurface element provided in the embodiments of this application.

[0029] Figure 4 shows a schematic diagram of the optical path corresponding to a certain pixel in the optical engine provided in the embodiment of this application.

[0030] Figure 5 shows a second schematic diagram of the structure of the metasurface element provided in the embodiment of this application.

[0031] Figure 6 shows a schematic diagram of the structure of the micro-display component provided in an embodiment of this application.

[0032] Explanation of reference numerals in the attached figures: 1. Substrate; 11. Side surface; 21. Micro-display component; 210. Pixel; 211. Light source; 212. Microdisplay chip; 22. Metasurface element; 221. Substrate; 222. Micro / nano structure; 22a. First part; 22b. Second part. Detailed Implementation

[0033] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0034] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0035] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0036] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0037] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0038] In traditional projection optical engines, the primary functions of the waveguide are image generation and light source provision. Specifically, a traditional projection optical engine generates image information through an internal display chip (such as LCOS, DLP, or LBS), and converts this information into light signals through a series of lens components. These light signals are then coupled into the waveguide by coupling elements formed on the waveguide, and guided by the waveguide, are finally coupled out by coupling elements formed on the waveguide and projected onto the user's eyes, forming a clear image.

[0039] In order to couple image light into the waveguide, traditional projection optical engines need to use a special coupling element (such as a coupling grating), which is set in the coupling area of ​​the traditional light guide device.

[0040] Therefore, this application provides a novel optical engine structure to solve the technical problem of complex overall architecture and large size of traditional projection optical engines.

[0041] This application proposes a novel optical engine structure. This optical engine not only possesses the functions of generating and modulating image rays, as in traditional projection optical engines, but also innovatively incorporates light coupling capabilities, simplifying the optical engine structure, reducing its size, and enriching its performance.

[0042] In this embodiment of the application, referring to FIG1, the optical engine includes: a micro-display component 21 for emitting image light; and a metasurface element 22, wherein the micro-display component 21 and the metasurface element 22 are attached together along the light transmission direction, and the metasurface element 22 is used to modulate the image light and couple the modulated image light into a light guide device.

[0043] In this embodiment, the optical engine consists of only two parts: a micro-display component 21 and a metasurface element 22. These two components of the optical engine will be analyzed in detail below.

[0044] In this embodiment, the main function of the microdisplay component 21 in the optomechanical system is to emit image light rays. The image light rays emitted by the microdisplay component 21 can be collimated light rays (parallel light rays) or decollimated light rays.

[0045] When the image light emitted by the microdisplay component 21 is collimated, the complexity of light control and phase modulation of the metasurface element 22 is simplified, and the design difficulty of the metasurface element 22 is reduced.

[0046] When the image light of the microdisplay component 21 is non-collimated, it will increase the difficulty of designing the metasurface element 22, but it will not affect the overall architecture of the optomechanical system in the embodiments of this application.

[0047] In this embodiment, the microdisplay component 21 and the metasurface element 22 are attached together along the light transmission direction. This attachment ensures that image light emitted from the microdisplay component 21 can be directly and efficiently transmitted to the metasurface element 22, reducing light loss and scattering.

[0048] Furthermore, the metasurface element 22 can modulate the light incident upon it. For example, the metasurface element 22 can modulate the phase, polarization, amplitude, and other characteristics of the image light. The bonding arrangement between the microdisplay component 21 and the metasurface element 22 further ensures the accuracy of the modulation process and also guarantees that the light will not be subjected to additional interference during transmission.

[0049] Furthermore, the micro-display component 21 and the metasurface element 22 are attached along the light transmission direction, making the entire optical engine structure more compact, which helps to reduce the size and weight of the optical engine and improve its portability and ease of use.

[0050] In this embodiment, the metasurface element 22 is composed of a metasurface structure. A metasurface structure is a structure including micro / nano structures 222. These micro / nano structures 222 are artificial layered material structures with dimensions at the subwavelength scale. These micro / nano structures 222 can achieve modulation of the polarization, amplitude, phase, and propagation characteristics of image light.

[0051] The metasurface element 22 modulates light through its micro / nano structures 222. When light is incident on the metasurface element 22, it interacts with these micro / nano structures 222, thereby changing the polarization, amplitude, phase, and propagation (direction and angle) properties of the light.

[0052] Referring to Figures 3a and 3b, an example structure of a metasurface element 22 is shown. The metasurface element 22 may include a substrate 221 and micro / nanostructures 222 located on the substrate 221. The micro / nanostructures 222 located on the substrate 221 may have the same or different shapes.

[0053] For example, referring to FIG5, another structure of the metasurface element 22 is shown. As shown in FIG3b and FIG5, the arrangement of the micro-nano structures 222 on the substrate 221 is not unique. Those skilled in the art can design the arrangement of the micro-nano structures 222 on the substrate 221 and the shape of each micro-nano structure according to the type of image light emitted from the micro-display component 21 and the type of optomechanical application to the light guide device.

[0054] There are no specific requirements for the thickness of the micro / nano structure 222; the thickness is typically a few wavelengths, usually a few micrometers. In the embodiments of this application, the main limitation is that the lateral (perpendicular to the direction of light propagation) dimension of the micro / nano structure 222 must be smaller than or close to the wavelength. For example, in the case where the micro / nano structure 222 is a nanopillar, the width of the nanopillar must be close to or smaller than the wavelength.

[0055] In this embodiment, the microdisplay component 21 and the metasurface element 22 are bonded together to form an optomechanical system, utilizing the structural features of the metasurface element 22. The metasurface element 22 has the function of modulating image light and coupling the modulated image light into a light guide device.

[0056] Specifically, in the embodiments of this application, the metasurface element 22 primarily functions to modulate image light. When image light emitted from the microdisplay component 21 shines onto the metasurface element 22, this light is modulated by the micro / nano structure 222 of the metasurface element 22.

[0057] Based on the micro / nano structure characteristics of the metasurface element 22, light undergoes changes in phase, amplitude, or polarization as it passes through, thereby achieving light modulation.

[0058] This part of the metasurface element 22 functions similarly to optical elements such as lenses in conventional optical engines. However, compared to conventional lenses, the metasurface element 22 has advantages such as being lighter, thinner, and easier to integrate.

[0059] Furthermore, the metasurface element 22 can also achieve more complex optical functions, such as multifocal focusing, zooming, and polarization control, which are difficult to achieve with traditional lenses. In other words, in this embodiment, the light modulation effect of the metasurface element 22 is superior to the light modulation effect of optical elements such as lenses in traditional optomechanical systems.

[0060] Furthermore, the metasurface element 22 also has the function of coupling the modulated image light into the light guide device. The light modulated by the metasurface element 22 has its propagation direction and characteristics adjusted according to predetermined requirements, which makes it easier and more efficient for these lights to couple into the light guide device. Light guide devices are typically used to guide light along a specific path to achieve specific imaging or illumination effects.

[0061] This part of the function of the metasurface element 22 is similar to that of the coupling element (such as a coupling grating) in a conventional light guide device. A coupling grating is a device used to couple light into the waveguide, and it usually has specific structures and parameters to achieve directional coupling of light. In the embodiments of this application, the metasurface element 22 directly couples the modulated light into the waveguide of the light guide device.

[0062] Compared to coupling gratings, metasurface elements 22 offer greater flexibility and customizability. By adjusting the microstructure and parameters of metasurface elements 22, image light emitted from them can be directly coupled into a light guide device without the need for coupling gratings, thus meeting a wider range of optical requirements. Furthermore, metasurface elements 22 also offer advantages such as being lighter, thinner, and easier to integrate.

[0063] In summary, by bonding the microdisplay component 21 to the metasurface element 22 and utilizing the structural features of the metasurface element 22 to modulate and couple light, the optomechanical design in this embodiment achieves a highly integrated, efficient, and flexible optical system. This design not only improves the overall performance of the optomechanical system but also facilitates further miniaturization and integration of the system.

[0064] In this embodiment of the application, referring to FIG1, the microdisplay component 21 and the metasurface element 22 are bonded together.

[0065] In this embodiment, the microdisplay component 21 and the metasurface element 22 are connected together by an adhesive bonding method. Firstly, the adhesive bonding provides stable mechanical support. As core components of the optomechanical system, the microdisplay component 21 and the metasurface element 22 need to maintain precise relative positions to ensure accurate light transmission and modulation. The adhesive bonding ensures a strong bond between these two components, preventing displacement or loosening under external factors such as vibration or impact, thereby guaranteeing the stability and reliability of the optomechanical system.

[0066] Secondly, adhesive bonding can also achieve good optical contact. In optomechanics, the quality of the contact surface between the microdisplay component 21 and the metasurface element 22 has a significant impact on the light transmission effect. Through adhesive bonding, the contact surface between the microdisplay component 21 and the metasurface element 22 can be ensured to be flat and smooth, reducing light scattering and loss on the contact surface, thereby improving the transmission efficiency and imaging quality of the optical system.

[0067] Furthermore, adhesive bonding offers advantages such as simple processing and low cost. Compared to traditional mechanical bonding methods, adhesive bonding eliminates the need for complex machining and assembly processes, significantly reducing production costs and time. Simultaneously, adhesive bonding can accommodate optical components of different shapes and sizes, providing greater flexibility and choice for the design and manufacturing of optical systems.

[0068] In a further embodiment, the adhesive layer between the microdisplay component 21 and the metasurface element 22 is annular.

[0069] In this embodiment, the adhesive layer between the microdisplay component 21 and the metasurface element 22 is annular. The annular adhesive layer can be located in the non-display area of ​​the microdisplay component 21 and in the non-working area of ​​the metasurface element 22, ensuring the normal transmission of image light emitted from the microdisplay component 21 and ensuring the modulation and coupling effect of the image light by the metasurface element 22.

[0070] Specifically, the annular adhesive layer is located in the non-display area of ​​the microdisplay component 21, meaning it does not block image light emitted from the microdisplay component 21. Thus, image light can be modulated and coupled through the metasurface element 22 without being obstructed by the adhesive layer.

[0071] Similarly, the annular adhesive layer is also located in the non-working area of ​​the metasurface element 22 (e.g., the edge region of the substrate 221 where no micro / nano structures 222 are disposed). This ensures that the working area of ​​the metasurface element 22 (i.e., the portion used to modulate and couple image light) is not adversely affected by the adhesive layer, such as stress, contamination, or damage.

[0072] It should be noted that although the adhesive layer is annular, it still provides a stable mechanical connection between the microdisplay component 21 and the metasurface element 22. This connection ensures that the relative positions of the two components in the optomechanism remain fixed, thereby guaranteeing the stability and reliability of the optomechanism.

[0073] For example, the type of adhesive between the microdisplay component 21 and the metasurface element 22 can be UV adhesive, epoxy AB adhesive, or optical resin adhesive, etc.

[0074] In a further embodiment, the bonding air gap between the microdisplay component 21 and the metasurface element 22 is less than 1 μm.

[0075] In this embodiment, the microdisplay component 21 and the metasurface element 22 do not need to be in direct contact. When the microdisplay component 21 emits image light, there can be a smaller gap between them. The smaller the gap between them, the less light leakage will occur.

[0076] In this embodiment, when the bonding air gap between the microdisplay component 21 and the metasurface element 22 is less than 1 μm, the pixel size 210 of the microdisplay component 21 (plus the lateral size expansion during light transmission) can be smaller than the size of the corresponding pixel region on the metasurface element 22 (the micro / nano structure 222 corresponding to a certain pixel 210). The metasurface element 22 can then modulate and couple the light emitted from its corresponding pixel 210. This modulation and coupling enables precise control of the light, including direction, intensity, and phase, thereby meeting various application requirements.

[0077] In a preferred embodiment of this application, the light emitted by the microdisplay component 21 is collimated light. The method by which the microdisplay component 21 emits collimated light includes: defining the light source 211 of the microdisplay component 21 as a collimated light source 211.

[0078] When the light source 211 of the micro display component 21 is a collimated light source 211, for example, the light source 211 is a laser light source 211 or the light source 211 is another collimated light source 211, such as an LED light source 211.

[0079] When the light source 211 is another collimated light source 211, the micro-display component 21 includes a light source body and a collimation assembly. The collimation assembly is located in the light emission path of the light source body.

[0080] In this example, the light source 211 is typically a high-brightness LED or other type of light-emitting element. These light sources 211 are capable of emitting light of sufficient intensity for subsequent processing and projection by the microdisplay chip 212.

[0081] The collimation component is a key part of the micro-display component 21 for achieving light collimation. It is located on the light emission path of the light source body to expand and collimate the light transmitted to it, making the light rays parallel and aligned in the same direction.

[0082] Alternatively, this can be understood as follows: In this approach, the microdisplay component 21 needs to achieve light collimation through an additional optical system (collimation assembly). Light collimation is achieved at the pixel level and may include optical elements such as microlens arrays or microcavity mirrors, which can collect, focus, and guide the light emitted by the light source 211 to form collimated image light.

[0083] When the light source 211 of the microdisplay component 21 is a laser light source 211, referring to Figure 6, the microdisplay component 21 includes only the light source 211 and the microdisplay chip 212. The collimated light source 211 can directly emit collimated light rays. The microdisplay chip 212 is typically a display element with high resolution and high-speed response capabilities, such as an LCD screen (transmissive screen). These display elements can modulate and image the light emitted by the collimated light source 211 to form a clear projected image.

[0084] Alternatively, in this approach, the micro-display component 21 directly uses a laser light source 211 with collimation characteristics to directly achieve light collimation.

[0085] For example, the light source 211 is a VCSEL laser, namely a vertical-cavity surface-emitting laser. In this embodiment, a VCSEL array is used as a micro-display array, resulting in high overall brightness and efficiency for the micro-display component 21. For instance, the VCSEL array provides light emission over a large area, enabling regional backlight modulation, reducing power consumption and improving overall efficiency. The array provides the backlight effect, while the light modulation employs a transmissive LCD screen or a reflective LCOS screen (requiring a specially designed waveguide, see the optical system disclosed in 202411254381.6) to achieve greater pixel density and control the light flux to achieve modulation.

[0086] In the overall architecture of a traditional optical-mechanical system, the micro-display component 21 usually needs to work in conjunction with a series of other optical components (such as lenses, mirrors, etc.) and mechanical structures (such as supports, adjustment mechanisms, etc.) to achieve the desired imaging or projection effect.

[0087] However, in this embodiment, we employ an innovative design approach: the microdisplay component 21 directly emits collimated image rays, which do not need to pass through intermediate traditional optical elements but are directly transmitted to the metasurface element 22. The metasurface element 22 is responsible for modulating the image rays emitted by the microdisplay component 21, thereby efficiently coupling these modulated image rays into the interior of a light guide device (e.g., an optical waveguide).

[0088] In this embodiment of the application, referring to FIG6, the micro display component 21 further includes a micro display chip 212, which is disposed on the light emission path of the light source 211.

[0089] In this embodiment, the microdisplay chip 212 is located in the light-emitting path of the light source 211, and its main function is to output image light carrying image information. The microdisplay chip 212 can employ different technologies, such as LCD (Liquid Crystal Display), LCOS (Liquid Crystal on Silicon), or Micro LED. These technologies utilize different physical principles to control the passage or reflection of light, thereby forming an image on the microdisplay chip 212.

[0090] It is important to note that when using Micro LED, the light source 211 itself has image modulation capabilities, thus eliminating the need for an integrated microdisplay chip 212. When the light source 211 uses Micro LED, the light source itself is the microdisplay chip, requiring no external modulation; that is, the Micro LED itself is the microdisplay component 21. However, the light scattering angle of Micro LED is too large, necessitating the design shown in Figure 4, i.e., collimating the light emitted by the Micro LED.

[0091] For example, considering the size requirements of the micro-display component 21, the micro-display component 21 is preferably a Micro LED. According to the specifications of Micro LED, the effective display sizes of Micro LED are 0.12 inches, 0.61 inches and 0.69 inches, and Micro LEDs of different sizes all have high resolution, which meets the requirements of optomechanical imaging.

[0092] In this embodiment of the application, referring to Figures 2, 3a, and 3b, and Figures 4 and 5, the metasurface element 22 is composed of subwavelength micro / nano structures 222. Each micro / nano structure 222 in the metasurface element 22 corresponds one-to-one with a pixel 210 in the microdisplay component 21. The micro / nano structure 222 modulates and refracts the light emitted from its corresponding pixel 210 into the light guide device.

[0093] In this embodiment, the subwavelength micro / nano structures 222 can modulate light with high precision. These micro / nano structures 222 can manipulate the phase, amplitude, polarization, and propagation characteristics of light, thereby achieving customized control of light. This allows the metasurface elements 22 to modulate the image light emitted from the microdisplay component 21 on the one hand, and to couple the modulated light into the light guide device on the other.

[0094] Specifically, by designing and optimizing the subwavelength micro / nano structure 222, the metasurface element 22 can achieve focusing, deflection, and phase modulation of light, which have advantages in imaging, display, and light coupling.

[0095] Furthermore, the extremely small size of the subwavelength micro / nano structure 222 enables the metasurface element 22 to achieve a high degree of integration. Compared with traditional optical elements, the metasurface element 22 is smaller and lighter, and is easier to integrate with the microdisplay component 21, thereby creating a powerful and compact optomechanical system.

[0096] For example, the subwavelength-sized micro / nano structure 222 includes any one or a combination of several of nanoblocks, nanopillars, nanostrips, and irregular structures (e.g., L-shaped or V-shaped).

[0097] In this example, the subwavelength micro / nanostructures 222 encompass regular and irregular structures such as nanoblocks, nanopillars, and nanostrips, and can be flexibly selected and designed according to the functions required by the metasurface element 22. When constructing the same metasurface element 22, a single type of micro / nanostructure 222 can be used, or at least two different types of micro / nanostructures 222 can be integrated to achieve the required functions of the metasurface element 22. For example, if the micro / nanostructure 222 is a V-shaped design, modulation can be achieved by changing the angle of the V-shape to alter the limiting of the light passing through it.

[0098] In this embodiment, referring to Figures 2 and 4, the micro / nano structure 222 (the smallest unit of the metasurface element 22) of the metasurface element 22 is adapted to the size of the pixel 210 in the microdisplay component 21. Due to this size effect, the micro / nano structure 222 can interact strongly with light waves, thereby achieving modulation of the light wave characteristics. The micro / nano structure 222 of the metasurface element 22 encodes (i.e., modulates the characteristics of the light) the image light emitted from its corresponding pixel 210, realizing the modulation and coupling of the image light.

[0099] Specifically, metasurface element 22 is a device composed of micro- and nanostructures that can precisely control the properties of light waves, such as phase, amplitude, polarization, and propagation.

[0100] Micro- and nanostructures 222 are the basic building blocks of metasurface elements 22. Their shape, size, and arrangement determine the metasurface's ability to control light waves.

[0101] Pixel 210 is the basic building block of microdisplay component 21, and each pixel 210 can emit light of a specific color and brightness.

[0102] Here, "encoding" refers to the specific manipulation of image light using the micro / nano structures 222 of the metasurface element 22, enabling the light to carry specific information or characteristics. This encoding is achieved through the shape, size, and arrangement of the micro / nano structures 222, which can influence the phase, amplitude, polarization, and propagation characteristics of the light.

[0103] "Modulation" refers to the precise control of the characteristics of light in an image, such as changing the phase, amplitude, polarization state, or propagation direction and angle of the light to achieve specific optical effects.

[0104] "Coupling" refers to the efficient connection of modulated light with light guide devices to ensure that the light can propagate and form an image in the expected manner.

[0105] In this embodiment, the micro / nano structure 222 of the metasurface element 22 achieves precise modulation of the image light emitted from its corresponding pixel 210 by specifically encoding (i.e., controlling the characteristics of the light). This modulated light is then efficiently coupled into a light guide device to achieve specific display effects or optical functions.

[0106] For example, the metasurface element 22 also includes a substrate 221 on which micro / nano structures 222 are formed.

[0107] In one embodiment, referring to Figures 2, 3a and 3b, the metasurface element 22 includes a dielectric layer formed by arranging a plurality of subwavelength-sized micro / nano structures 222 along the light transmission direction. The dielectric layer is configured to modulate the image light and couple the modulated image light into a light guide device.

[0108] In this embodiment, referring to Figures 3a and 3b, the metasurface element 22, along the light transmission path, includes a dielectric layer composed of a plurality of subwavelength micro / nano structures 222 arranged in an orderly manner. This dielectric layer is specially designed to precisely modulate image light, thereby effectively coupling the modulated image light into the light guide device to achieve light transmission and control.

[0109] In other words, in this embodiment, the metasurface element 22 includes only one dielectric layer. This single dielectric layer has two functions: on the one hand, it can modulate the image light emitted from the microdisplay component 21; on the other hand, it enables the modulated light to couple into the light guide device.

[0110] Referring to Figure 2, a schematic diagram of the optical path corresponding to a certain pixel in the optomechanical system is shown. The light emitted from a certain pixel 210 in the micro-display component 21 is transmitted to the corresponding micro / nano structure 222, and the transmission characteristics of the light change.

[0111] In this embodiment, the metasurface element 22 includes a dielectric layer, which is a planar or curved structure composed of subwavelength micro / nanostructures 222 (such as nanoblocks, nanopillars, nanostrips, etc.) arranged in an orderly manner. These micro / nanostructures 222 are much smaller than the wavelength of light, so they can interact strongly with light waves, thereby changing the propagation characteristics of light.

[0112] When light rays pass through this dielectric layer, they interact with the micro / nano structures 222 within it. This interaction causes changes in the phase, amplitude, polarization state, and propagation characteristics of the light rays, i.e., the light rays are modulated.

[0113] The modulated image light is then effectively coupled into the light guide. The coupling process involves guiding the modulated light to the input of the light guide and ensuring that the light propagates in the desired manner within the light guide. Once coupled into the light guide, the light can then travel along the path of the light guide.

[0114] By precisely designing the structure of the dielectric layer and light guide device of the metasurface element 22, precise control over parameters such as light transmission path, direction, and intensity can be achieved.

[0115] It should be noted that Figures 3a and 3b only illustrate one structure of the metasurface element 22. Based on the light emission characteristics of the micro-display component 21, those skilled in the art can adjust the arrangement (e.g., density) and shape of the micro-nano structures 222 in the metasurface element 22.

[0116] In another embodiment, referring to Figures 4 and 5, the metasurface element 22 includes a first portion 22a and a second portion 22b along the light transmission direction. Both the first portion 22a and the second portion 22b include a dielectric layer formed by arranging a plurality of subwavelength-sized micro / nano structures 222.

[0117] The first portion 22a is configured to modulate the image light, and the second portion 22b is configured to couple the modulated image light into the light guide device.

[0118] In this embodiment, the metasurface element 22 is divided into two main parts in the light transmission direction: a first part 22a and a second part 22b. Referring to FIG4, a schematic diagram of the optical path of a pixel in the optomechanism is shown. The light emitted from a pixel 210 in the microdisplay component 21 passes sequentially through a micro / nano structure 222 in the first part 22a of the metasurface element 22 and a micro / nano structure 222 in the second part 22a of the metasurface element 22.

[0119] Both the first part 22a and the second part 22b contain a dielectric layer formed by the orderly arrangement of multiple subwavelength micro / nano structures 222. This structural design enables the metasurface element 22 to modulate image light (collimate image light) and couple the modulated image light into the light guide device through the structures of the first part 22a and the second part 22b.

[0120] Specifically, referring to FIG4, the main function of the micro / nano structure 222 of the first portion 22a is to modulate (collimate) the image light. Since the first portion 22a contains subwavelength micro / nano structures 222, these structures can interact strongly with light, thereby achieving precise optical modulation. In this embodiment, the micro-display component 21 is a Micro LED.

[0121] Referring to Figure 4, the micro / nano structure 222 of the second part 22b further modulates (the phase, propagation, and other characteristics of the light) the image light modulated by the first part 22a and effectively couples it into the light guide device. The coupling process involves refracting the light emitted from each pixel 210 of the microdisplay component 21 to the light guide device (refractive effect) to ensure that the light can enter the light guide device efficiently and be transmitted therein.

[0122] This design, which divides the metasurface element 22 into two independent but cooperative parts, allows the entire element to adapt more flexibly to different optical requirements and provides higher optical performance and control precision.

[0123] It should be noted that Figure 5 only schematically illustrates the structure of a portion of the metasurface element 22. Those skilled in the art can adjust the structure of the first part 22a and the structure of the second part 22b according to the light emission characteristics of the microdisplay component 21.

[0124] This application also provides a light guide device, which includes the aforementioned optomechanical mechanism. The optomechanical mechanism is integrated into the coupling region of the light guide device.

[0125] It is worth noting that, unlike common traditional light guide devices, the light guide device in this embodiment does not have traditional coupling elements, such as coupling gratings, configured in the coupling region. Furthermore, no traditional optical engine is installed at the corresponding location in the coupling region. Instead, a novel optical engine is integrated in the coupling region. This novel optical engine does not use traditional optical lenses, significantly reducing the overall size. Moreover, this novel optical engine not only modulates the image light but also efficiently couples the modulated light into the substrate, thus achieving a technological breakthrough and optimization. In contrast, traditional coupling gratings, limited by their fabrication process, cannot achieve optimization across the entire angle. Traditional gratings often exhibit multiple negative dimensions (incorrect directions) of coupling, typically resulting in coupling efficiency below 20% at large FOV (greater than 50 degrees). In this example, however, because the modulation of the metasurface element 22 is at the pixel level, the provided coupling efficiency is almost lossless.

[0126] This application also provides a near-eye display device. The near-eye display device includes the aforementioned light guide device. A near-eye display device is a wearable device, typically designed to present images or information directly in front of a user's eyes without requiring the user to hold it or move it away from their eyes. The near-eye display device can be virtual reality (VR), augmented reality (AR), or mixed reality (MR).

Claims

1. An optical engine, wherein, The optical engine includes: Miniature display components used to emit light for images; A metasurface element is provided, wherein the microdisplay component and the metasurface element are attached together along the light transmission direction, and the metasurface element is used to modulate the image light and couple the modulated image light into the light guide device.

2. The optical engine according to claim 1, wherein, The micro-display component and the metasurface element are bonded together.

3. The optical engine according to claim 2, wherein, The adhesive layer between the microdisplay component and the metasurface element is annular.

4. The optical engine according to claim 2 or 3, wherein, The bonding air gap between the microdisplay component and the metasurface element is less than 1 μm.

5. The optical engine according to claim 1, wherein, The micro-display component includes a light source, which is a collimated light source.

6. The optical engine according to claim 5, wherein, The micro-display component also includes a micro-display chip, which is disposed on the light emission path of the light source.

7. The optical engine according to claim 1, wherein, The metasurface element is composed of subwavelength micro-nano structures, and each micro-nano structure in the metasurface element corresponds one-to-one with a pixel in the micro-display component. The micro-nano structure modulates and refracts the light emitted from its corresponding pixel into the light guide device.

8. The optical engine according to claim 7, wherein, The metasurface element includes a dielectric layer formed by arranging a plurality of subwavelength micro-nano structures along the light transmission direction. The dielectric layer is configured to modulate the image light and couple the modulated image light into the light guide device. or, The metasurface element includes a first part and a second part along the light transmission direction, and both the first part and the second part include a dielectric layer formed by the arrangement of multiple subwavelength-sized micro-nano structures; The first part is configured to modulate the image light, and the second part is configured to couple the modulated image light into the light guide device.

9. The optical engine according to claim 7 or 8, wherein, The subwavelength-scale micro / nanostructures include any one or a combination of several of the following: nanoblocks, nanopillars, nanostrips, and irregular patterns.

10. A light guide device, wherein, The light guide device includes an optomechanic as described in any one of claims 1-9.

11. A near-eye display device, wherein, The near-eye display device includes the light guide device as described in claim 10.

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