Optical display system, preparation method thereof and near-to-eye display device

Abstract

The invention provides an optical display system, a preparation method thereof and a near-to-eye display device. The optical display system comprises an optical-mechanical module, the optical-mechanical module comprises a lens cone and at least two optical-mechanical units, each optical-mechanical unit is used for generating image light of one color, and the colors of the image light generated by different optical-mechanical units are different; the optical waveguide comprises a waveguide substrate, a coupling-in grating assembly arranged in a coupling-in area of the waveguide substrate, and a coupling-out grating assembly arranged in a coupling-out area of the waveguide substrate; wherein the optical-mechanical module is arranged on one side of the coupling-in area of the optical waveguide, and the coupling-in grating assembly is used for coupling image light from the optical-mechanical units into the waveguide substrate; the coupling-out grating assembly is used for synthesizing the image light of different colors transmitted by the waveguide substrate into color image light and coupling out the color image light. The optical display system can reduce the size, reduce the cost and improve the light utilization rate.

Description

Technical Field

[0001] This invention relates to the field of near-eye display technology, and more particularly to an optical display system and its manufacturing method, and a near-eye display device. Background Technology

[0002] Augmented Reality (AR) display devices, especially near-eye displays such as AR glasses, place stringent demands on the miniaturization, weight reduction, and high brightness of their core imaging component—the optical engine. Currently, commonly used optical engine technologies include Liquid Crystal on Silicon (LCoS), Digital Light Processing (DLP), Micro Light-Emitting Diode (Micro-LED), and Laser Beam Scanning (LBS).

[0003] Micro-LED, as a self-emissive device, shows significant potential for further miniaturization of optomechanical systems due to its elimination of the need for external lighting systems. However, monolithically integrated full-color µLED display technology is still immature. To obtain color images, existing solutions typically employ three µLED chips that emit red (R), green (G), and blue (B) monochromatic light respectively, relying on complex optical systems such as color-splitting and combining prisms for color combining. This approach not only significantly increases the size and structural complexity of the optomechanical module, raising costs, but also introduces additional light utilization losses due to multiple reflections and absorptions at the prism interface. Summary of the Invention

[0004] This application provides an optical display system and its manufacturing method, as well as a near-eye display device, which can reduce volume, lower cost, and improve light utilization.

[0005] This application provides an optical display system, including: An optical engine module, comprising a lens barrel and at least two optical engine units, each of the optical engine units being used to generate image light of a certain color, and different optical engine units generating image light of different colors; An optical waveguide, comprising a waveguide substrate, a coupling grating assembly disposed in a coupling region of the waveguide substrate, and a coupling grating assembly disposed in a coupling out region of the waveguide substrate. The optomechanical module is disposed on one side of the coupling region of the optical waveguide, and the coupling grating assembly is used to couple image light from multiple optomechanical units into the waveguide substrate; the coupling grating assembly is used to combine image light of different colors transmitted on the waveguide substrate into color image light and couple it out.

[0006] In some embodiments, each of the optical-mechanical units includes an image source and a projection lens. The projection lens is correspondingly disposed on the light-emitting side of the image source. The projection lens includes a plurality of optical functional layers arranged sequentially. Each optical functional layer is one of a wafer-level optical lens, a diffractive optical element, and a metasurface structure.

[0007] In some embodiments, the inner wall of the lens barrel and / or the side wall of the optical engine unit is made of a light-absorbing material or coated with a light-absorbing coating.

[0008] In some embodiments, the optical axes of the optomechanical units are parallel to each other.

[0009] In some embodiments, the number of the optomechanical units is three, which are used to generate red, green and blue image light respectively; the coupling grating assembly includes three coupling gratings, which correspond one-to-one with the three optomechanical units.

[0010] In some embodiments, the optical waveguide further includes a first extended grating and a second extended grating disposed on the waveguide substrate; the coupling grating assembly includes a first coupling grating and a second coupling grating; Specifically, green light from the green optomechanical unit is coupled into the corresponding insertion grating and then guided to the first output grating by the first extended grating; red light from the red optomechanical unit is coupled into the corresponding insertion grating and then guided to the second output grating by the second extended grating; and blue light from the blue optomechanical unit is coupled into the corresponding insertion grating and then coupled out by both the first output grating and the second output grating.

[0011] In some embodiments, The grating vectors of the plurality of coupled-in gratings, the first extended grating, the second extended grating, the first coupled-out grating, and the second coupled-out grating satisfy the following relationship: KinG+KepeG+KocG=0(1); KinR+KepeR+KocR=0(2); KinB+KocG+KocR=0(3); Wherein, KinG, KinR, and KinB are the grating vectors of the coupled gratings corresponding to green light, red light, and blue light, respectively; KepeG is the grating vector of the first extended grating, and KepeR is the grating vector of the second extended grating; KocG is the grating vector of the first coupled-out grating, and KocR is the grating vector of the second coupled-out grating.

[0012] In some embodiments, the number of optomechanical units is two, including a red optomechanical unit for generating red light and a blue-green optomechanical unit for generating blue-green composite light; the coupling grating assembly includes two coupling gratings, corresponding to the red optomechanical unit and the blue-green optomechanical unit respectively; the optical waveguide further includes a third extended grating and a fourth extended grating; the coupling grating assembly includes a third coupling grating; Wherein, the blue-green light from the blue-green optomechanical unit is coupled into the corresponding coupled-in grating and then guided out by the third extended grating to the third coupled-out grating; the red light from the red optomechanical unit is coupled into the corresponding coupled-in grating and then guided out by the fourth extended grating to the third coupled-out grating.

[0013] In some embodiments, the grating vectors of the coupled-in grating assembly, the third extended grating, the fourth extended grating, and the third coupled-out grating satisfy the following relationship: KinGB+KepeGB+Koc=0(4); KinR+KepeR+Koc=0(5); Wherein, KinGB and KinR are the grating vectors of the coupled grating components corresponding to green-blue light and red light, respectively; KepeGB is the grating vector of the third extended grating, and KepeR is the grating vector of the fourth extended grating; Koc is the grating vector of the third coupled-out grating.

[0014] In some embodiments, the coupling grating assembly includes a coupling grating corresponding to a plurality of optomechanical units for receiving light emitted from the plurality of optomechanical units.

[0015] This application provides a method for fabricating an optical display system, the method comprising: A lens barrel and multiple optical-mechanical units are provided, and the optical-mechanical units are encapsulated in the lens barrel to form an optical-mechanical module. The multiple optical-mechanical units are used to generate image light of different colors respectively. An optical waveguide is provided, the optical waveguide including a waveguide substrate, a coupling grating assembly and a coupling grating assembly, the coupling grating assembly being disposed on the coupling region of the waveguide substrate, and the coupling grating assembly being disposed on the coupling region of the waveguide substrate; The optomechanical module is configured to couple the image light from the plurality of optomechanical units into the interior of the waveguide substrate. The coupling grating assembly is used to couple the image light from the plurality of optomechanical units into the interior of the waveguide substrate. The coupling grating assembly is used to combine the image light of different colors transmitted on the waveguide substrate into a color image light and couple it out.

[0016] In some embodiments, a plurality of optomechanical units are provided, and the fabrication method includes: Multiple wafers are provided, and an optical functional layer is formed on each of the wafers respectively; Multiple optical functional layers are aligned and bonded using a wafer bonding process to form a projection lens; Provide at least two image sources, each used to generate light of different colors; The image source is matched one-to-one with the corresponding optical path in the projection lens to form an optomechanical unit.

[0017] This application also provides a near-eye display device, including the above-described optical display system; or including an optical display system prepared by the above-described optical display system preparation method.

[0018] This application provides an optical display system, its fabrication method, and a near-eye display device. The optical display system includes an optomechanical module and an optical waveguide. By encapsulating multiple independent optomechanical units within the same lens barrel, a compact, integrated optomechanical module is formed, replacing the complex optical structure using dichroic prisms for color combining in traditional solutions. This significantly reduces the overall volume and lowers system complexity and cost. A coupling grating assembly is used to combine different colors of image light transmitted within the waveguide substrate into a single colored image light and couple it out to the human eye. This color combining process is completed at the waveguide end, replacing the traditional prism color combining scheme at the optomechanical end. This not only further reduces the number of optical components and system volume but also avoids light absorption and interface reflection losses caused by color combining prisms, thereby improving overall light utilization. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of an optical display system provided in an embodiment of this application.

[0021] Figure 2 This is a schematic diagram of the first structure of the optomechanical unit provided in the embodiments of this application.

[0022] Figure 3 This is a schematic diagram of a second structure of the optomechanical unit provided in an embodiment of this application.

[0023] Figure 4 This is a schematic diagram of a third structure of the optomechanical unit provided in an embodiment of this application.

[0024] Figure 5 This is a schematic diagram of the structure of the optomechanical module provided in an embodiment of this application.

[0025] Figure 6 This is a schematic diagram of a first structure of an optical waveguide provided in an embodiment of this application.

[0026] Figure 7 The grating vector diagram of the optical waveguide corresponding to Embodiment 1 provided in this application.

[0027] Figure 8 This is a schematic diagram of a second structure of an optical waveguide provided in an embodiment of this application.

[0028] Figure 9 The grating vector diagram of the optical waveguide corresponding to Embodiment 2 provided in this application.

[0029] Figure 10 This is a schematic diagram of a third structure of an optical waveguide provided in an embodiment of this application.

[0030] Figure 11 The grating vector diagram of the optical waveguide corresponding to Embodiment 3 of this application is provided as an example of this application.

[0031] Figure 12 This is a schematic diagram of the first process for fabricating an optical display system provided in an embodiment of this application.

[0032] Figure 13 This is a schematic diagram of a second process for fabricating an optical display system provided in an embodiment of this application. Detailed Implementation

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0034] This application provides an optical display system and its fabrication method, as well as a near-eye display device, which can reduce size, lower cost, and improve light utilization. The following is a detailed description in conjunction with the accompanying drawings. It should be noted that the accompanying drawings and the optical path diagrams in the specific embodiments are for illustrative purposes only. The actual grating layout, optical path direction, and the number and position of the extended gratings can be adjusted according to the specific optical design, all of which fall within the scope of protection of this application.

[0035] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of an optical display system provided in an embodiment of this application.

[0036] This application provides an optical display system 100, which includes an optomechanical module 10 and an optical waveguide 20.

[0037] The optical engine module 10 includes a lens barrel 11 and at least two optical engine units 12. Each optical engine unit 12 is used to generate image light of a single color, and different optical engine units 12 generate image light of different colors. An optical engine unit 12 refers to an independent imaging unit that integrates a light source, a light modulator, and its corresponding projection optical system. For a specific embodiment, please refer to... Figure 2 , Figure 2 This is a schematic diagram of a first structure of the optomechanical unit provided in an embodiment of this application. Multiple optomechanical units 12 can respectively generate red (R), green (G), and blue (B) primary color image light, which are then combined optically to achieve full-color display. In another embodiment, please refer to... Figure 3 , Figure 3 This is a schematic diagram of a second structure of the optomechanical unit provided in the embodiments of this application. The optomechanical unit 12 can also adopt a structure of two optomechanical units 12. For example, one unit generates composite color image light of blue (B) and green (G), and the other unit generates red (R) image light. The desired color display effect can also be achieved through optical synthesis.

[0038] By encapsulating multiple independent optomechanical units 12 within the same lens barrel 11, a compact integrated optomechanical module 10 is formed, replacing the complex optical structure of color combining using dichroic prisms in traditional solutions, thereby significantly reducing the overall volume and lowering system complexity and cost.

[0039] Please continue reading. Figure 1The optical waveguide 20 includes a waveguide substrate 21, a coupling grating assembly 22 disposed in the coupling region of the waveguide substrate 21, and a coupling grating assembly 23 disposed in the coupling region of the waveguide substrate 21. The waveguide substrate 21 can be made of a high-refractive-index transparent material, such as glass, polymer, or silicon carbide (SiC). High-refractive-index materials such as SiC help to expand the total internal reflection angle range, reduce optical artifacts such as rainbow patterns, and improve the system's field of view and image clarity. The coupling region refers to the area on the waveguide specifically used to receive external image light and guide it into the waveguide, while the coupling region corresponds to the area that guides the image light transmitted within the waveguide to the human eye.

[0040] The optomechanical module 10 is located on one side of the coupling region of the optical waveguide 20, so that the image light emitted from each optomechanical unit 12 can be aligned and incident on the coupling grating assembly 22.

[0041] The coupling grating assembly 22 is used to couple the image light from the optomechanical unit 12 into the waveguide substrate. The coupling grating assembly 22 can be designed as multiple independent sub-gratings, each optimized for the incident angle of different colors of light; or a multifunctional grating with wavelength and angle selectivity can be used to achieve efficient and selective coupling of multiple incident lights.

[0042] The coupling grating assembly 23 is used to combine different colors of image light transmitted through the waveguide substrate into a color image light and couple it out to the human eye. This color combining process is completed using the optical waveguide 20, replacing the traditional prism color combining scheme at the optomechanical end. This not only further reduces the number of optical components and the system size, but also avoids the light absorption and interface reflection losses caused by the color combining prism, thereby improving the overall light utilization rate.

[0043] The input grating assembly 22 and the output grating assembly 23 can be located on the same side of the waveguide substrate 21 or distributed on both sides of the waveguide substrate 21.

[0044] Please see Figure 4 , Figure 4 This is a schematic diagram of a third structure of the optomechanical unit provided in an embodiment of this application.

[0045] Each optomechanical unit 12 includes an image source 121 and a projection lens 122. The image source 121 is a micro light-emitting diode (µLED) or a laser diode (LD). Such light sources have high brightness, high response speed and miniaturization characteristics, and are especially suitable for optical display systems 100 with requirements for size and power consumption.

[0046] The projection lens 122 is positioned on the light-emitting side of the image source 121. The projection lens 122 includes multiple sequentially arranged optical functional layers 1221. Each optical functional layer 1221 is one of a wafer-level optical (WLO) lens, a diffractive optical element (DOE), or a metasurface structure. By combining multiple optical functional layers 1221, flexible designs can be made to meet the requirements of aberration correction, beam shaping, and collimation, achieving the required optical performance while greatly reducing the axial dimension of the lens.

[0047] The projection lens 122 is a multi-layer lens stack integrated through wafer bonding technology. This fabrication method includes: fabricating optical functional layers 1221 containing the aforementioned wafer-level optical lenses, diffractive optical elements, or metasurface structures on multiple wafers using semiconductor processes such as photolithography, etching, and nanoimprinting; subsequently, aligning and bonding these optical functional layers 1221 together using wafer bonding processes such as thermo-pressing, anodic bonding, or adhesive bonding to form a monolithic, multi-layer integrated lens stack. This fabrication method overcomes the limitations of traditional optical lenses that rely on grinding, molding, and individual assembly, achieving extreme flatness and miniaturization of the projection lens 122. Furthermore, due to the high consistency and parallel processing capabilities of semiconductor processes, it is suitable for low-cost, mass production.

[0048] The optical axes of the optomechanical units 12 are parallel to each other and all point towards the coupling region of the optical waveguide 20. Beams from different optomechanical units 12 carrying image information of different colors (such as red, green, and blue) propagate along this parallel direction and are incident on the coupling region.

[0049] The core physical basis of this feature lies in the parallelism of the optical axes of the projection lenses 122. Each projection lens 122 within the optomechanical unit 12 is typically designed to process only light from its corresponding image source 121, thus possessing a unique optical axis in its optical design—the optical axis of symmetry of the projection lens 122, which is also the central reference line for ideal beam propagation. This solution ensures that the optical axes of multiple independent projection lenses 122 remain parallel after integration through precise mechanical structural design, such as a unified mounting reference surface within the lens barrel 11, and / or advanced manufacturing processes, such as the synchronous forming of multi-lens stacks in wafer bonding.

[0050] Understandably, the parallel optical axis design allows multiple optomechanical units 12 to be arranged side-by-side and closely within the lens barrel 11, greatly improving spatial integration and significantly reducing module size. Parallel incident light onto the waveguide coupling region provides regular input conditions for the design of the coupling grating 221, greatly simplifying parameter optimization and system alignment, and improving assembly efficiency and yield. This parallel optical axis design ensures that the image light generated by the optomechanical unit 12 can be efficiently and accurately guided to the coupling region of the optical waveguide 20 and received by the coupling grating assembly 22.

[0051] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of the optomechanical module provided in the embodiments of this application. To suppress stray light reflection within the system and avoid its adverse effect on imaging contrast, the inner wall of the lens barrel 11 and / or the side walls of each optomechanical unit 12 are made of a light-absorbing material, such as a black material; or, a light-absorbing coating is applied to its inner surface, such as a black matte varnish or a special light-absorbing film. This design can effectively absorb any unexpected reflected or scattered light that may be generated inside the lens barrel 11 or in the gaps between the optomechanical units 12, thereby improving the purity and signal-to-noise ratio of the final output image, enabling the optical display system 100 to achieve a clear, high-contrast display effect even in high ambient light backgrounds.

[0052] In another alternative embodiment, the optical engine module may omit the conventional lens barrel 11. Specifically, the optical engine unit 12 achieves optical isolation and mechanical fixation by coating its sidewalls with a light-absorbing coating, and is directly aligned with the coupling area of ​​the optical waveguide 20. This design further reduces the weight and structural complexity of the optical display system 100, making it suitable for near-eye display devices with extreme requirements for thickness and weight.

[0053] Example 1 Please see Figure 6 , Figure 6 This is a schematic diagram of a first structure of an optical waveguide provided in an embodiment of this application.

[0054] This embodiment provides a specific implementation of an optical display system 100 for augmented reality.

[0055] The optomechanical unit 12 consists of three units, which are used to independently generate image light of the three primary colors: red (R), green (G), and blue (B). This discrete three-primary-color light generation architecture is beneficial for subsequent high-purity color synthesis.

[0056] In the coupling region of the optical waveguide 20, the coupling grating assembly 22 includes three independent coupling gratings 221, each corresponding to one of the three optomechanical units 12. The grating parameters of each coupling grating 221, such as period, orientation, and modulation depth, are optimized for the center wavelength and specific incident angle of its corresponding color light, thereby achieving the highest efficiency coupling of the image light into the waveguide substrate 21. This one-to-one coupling design, compared to using a single grating to process multi-wavelength light, can significantly reduce the difference in propagation angle of each color light caused by grating dispersion, suppressing chromatic aberration at its source.

[0057] The optical waveguide 20 also includes a first extended grating 24 and a second extended grating 25 disposed on the waveguide substrate 21, which are used to guide and manage the propagation direction of the coupled specific color light.

[0058] Meanwhile, the waveguide's coupling region has a coupling grating assembly 23, which includes a first coupling grating 231 and a second coupling grating 232.

[0059] The coupling grating 221, the extended grating, and the coupling grating can be of the type of surface relief grating, volume holographic grating, polarization volume holographic grating, or metasurface grating, and can be fabricated on the waveguide substrate 21 by nanoimprinting, photolithography, or holographic recording processes.

[0060] The optical path operation mechanism of this embodiment is as follows: Green light from the green optomechanical unit is coupled into the corresponding insertion grating 221 and then guided by the first extended grating 24 to the first output grating 231 for coupling out; Red light from the red optomechanical unit is coupled into the corresponding insertion grating 221 and then guided by the second extended grating 25 to the second output grating 232 for coupling out; Blue light from the blue optomechanical unit is coupled into the corresponding insertion grating 221 and then coupled out by the first output grating 231 and the second output grating 232 together.

[0061] Through the above optical path design, blue light is coupled out by two coupling gratings and combined with the designated coupling paths of red and green light, ensuring that at the final exit pupil, the red, green and blue image lights can achieve precise spatial superposition and color fusion.

[0062] For details, please refer to Figure 6 as well as Figure 7 , Figure 7 The grating vector diagram of the optical waveguide corresponding to Embodiment 1 provided in this application, wherein the grating vectors of the plurality of coupled-in gratings 221, the first extended grating 24, the second extended grating 25, the first coupled-out grating 231 and the second coupled-out grating 232 satisfy the following relationships (1) to (3): KinG+KepeG+KocG=0(1).

[0063] KinR+KepeR+KocR=0(2).

[0064] KinB+KocG+KocR=0(3).

[0065] Wherein, KinG, KinR, and KinB are the grating vectors of the coupled grating 221 corresponding to green light, red light, and blue light, respectively; KepeG is the grating vector of the first extended grating 24, and KepeR is the grating vector of the second extended grating 25; KocG is the grating vector of the first coupled grating 231, and KocR is the grating vector of the second coupled grating 232.

[0066] According to equations (1) to (3) above, through targeted grating design, different color image lights from different optomechanical units 12 can be transmitted with the same or very close total internal reflection angles after being coupled into the waveguide substrate 21. Specifically, by coordinating the vectors of the coupling grating 221, the extended grating, and the coupling grating, for example, by satisfying the grating vector relationship, the reflection angles of the total internal reflection propagation of red, green, blue, and other colors of light in the waveguide are consistent.

[0067] The above design effectively overcomes the problem caused by the separation of propagation angles of different colors due to grating dispersion, significantly improving the color uniformity and brightness uniformity of the final synthesized color image, avoiding color difference or color separation; it allows each color channel to make full use of the total internal reflection condition of the waveguide, which helps to expand the overall field of view of the system; it simplifies the optical path management in the waveguide and improves the light energy utilization rate.

[0068] Example 2 Please see Figure 8 , Figure 8 This is a schematic diagram of a second structure of the optical waveguide provided in an embodiment of this application. This embodiment provides another specific implementation of the augmented reality optical display system 100, which, while ensuring full-color display capability, simplifies the system structure and optical path management by further integrating the optomechanical unit 12, thereby helping to reduce costs and improve production yield.

[0069] There are two optomechanical units 12, including a red optomechanical unit for generating red light and a blue-green optomechanical unit for generating blue-green composite light. The blue-green optomechanical unit refers to an image source 121 in this unit that can simultaneously emit blue (B) and green (G) light. This can be achieved, for example, by using a micro-light-emitting diode (µLED) chip capable of emitting both blue and green light, or by vertically stacking or horizontally arranging blue and green chips at the pixel level and integrating driving circuitry. Thus, the two optomechanical units 12 together cover the three primary colors required for color display.

[0070] The coupling grating assembly 22 includes two coupling gratings 221, corresponding to the red optomechanical unit and the blue-green optomechanical unit, respectively. One coupling grating 221 is optimized for the wavelength and incident angle of red light (R), while the other coupling grating 221 is designed for the characteristic wavelengths of blue light (B) and green light (G) to efficiently couple the two image beams into the waveguide substrate 21.

[0071] The optical waveguide 20 also includes a third extended grating 26 and a fourth extended grating 27; the coupling grating assembly 23 includes a third coupling grating 233. The third extended grating 26 and the fourth extended grating 27, as beam guiding elements, are disposed on the propagation path between the coupling region and the coupling region. The coupling region is provided with a third coupling grating 233, which serves as the exit point for ultimately combining multicolor light into a single beam and guiding it to the human eye.

[0072] The optical path operation process of this embodiment is as follows: the blue-green light from the blue-green optomechanical unit is coupled into the corresponding coupling grating 221 and then guided to the third coupling grating 233 by the third extended grating 26; the red light from the red optomechanical unit is coupled into the corresponding coupling grating 221 and then guided to the third coupling grating 233 by the fourth extended grating 27.

[0073] To ensure that the red, blue, and green light maintain consistent angles as they propagate within the waveguide and achieve pixel-level precise color overlap upon final coupling to avoid color differences, this embodiment employs a rigorous vector design for the grating system.

[0074] For details, please continue reading. Figure 8 as well as Figure 9 , Figure 9 The grating vector diagram of the optical waveguide corresponding to Embodiment 2 provided in this application. The grating vectors of the coupling-in grating 221, the third extended grating 26, the fourth extended grating 27, and the third coupling-out grating 233 satisfy the following relationships (4) to (5): KinGB+KepeGB+Koc=0(4).

[0075] KinR+KepeR+Koc=0(5).

[0076] Wherein, KinGB and KinR are the grating vectors of the coupled grating 221 corresponding to green-blue light and red light, respectively; KepeGB is the grating vector of the third extended grating 26; KepeR is the grating vector of the fourth extended grating 27; and Koc is the grating vector of the third coupled grating 233.

[0077] The satisfaction of the above equations (4) and (5) ensures that the red light and blue-green light propagate at the same angle in the waveguide, and finally achieve pixel-level overlap at the coupling grating, effectively avoiding color shift and aberration.

[0078] This embodiment employs two optomechanical units 12 (red light + blue-green light) and a matching dual-path guidance, single-point color combining optical waveguide 20. While maintaining excellent optical performance, it effectively reduces the number of the core component, optomechanical unit 12, and the number of gratings required on the waveguide. This demonstrates an optimized balance between system compactness, manufacturing cost, and display performance, providing a more cost-effective preferred solution for the mass production of augmented reality devices.

[0079] Example 3 Please see Figure 10 , Figure 10 This is a schematic diagram of a third structure of an optical waveguide provided in an embodiment of this application.

[0080] This embodiment provides another specific implementation of the augmented reality optical display system 100. While ensuring full-color display capability, it further integrates the optomechanical unit 12, which simplifies the system structure and optical path management, and helps to reduce costs and improve production yield.

[0081] There are two optomechanical units 12, including a red optomechanical unit for generating red light and a blue-green optomechanical unit for generating blue-green composite light. The two optomechanical units 12 together cover the three primary colors required to achieve color display.

[0082] The coupling grating assembly 22 includes two coupling gratings 221, corresponding to the red optomechanical unit and the blue-green optomechanical unit, respectively. One coupling grating 221 is optimized for the wavelength and incident angle of red light (R), while the other coupling grating 221 is designed for the characteristic wavelengths of blue light (B) and green light (G) to efficiently couple the two image beams into the waveguide substrate 21.

[0083] The optical waveguide 20 also includes a fifth extended grating 28 and a sixth extended grating 29; the coupling grating assembly 23 includes a fourth coupling grating 234 and a fifth coupling grating 235. The fifth extended grating 28 and the sixth extended grating 29, as beam guiding elements, are disposed on the propagation path between the coupling-in region and the coupling-out region. The coupling-out region, provided with the fourth coupling grating 234 and the fifth coupling grating 235, serves as the exit point for ultimately combining multicolor light into a single beam and guiding it to the human eye.

[0084] The optical path operation process of this embodiment is as follows: the blue-green light from the blue-green optomechanical unit is coupled into the corresponding coupling grating 221 and then guided to the fourth coupling grating 234 by the fifth extended grating 28; the red light from the red optomechanical unit is coupled into the corresponding coupling grating 221 and then guided to the fifth coupling grating 235 by the sixth extended grating 29.

[0085] To ensure consistent angular distribution of red, blue, and green light during propagation within the waveguide and to achieve pixel-level color accuracy upon final coupling, thus avoiding color difference, this embodiment employs a rigorous vector design for the grating system. Please continue reading. Figure 10 as well as Figure 11 , Figure 11The grating vector diagram of the optical waveguide corresponding to Embodiment 3 provided in this application is shown. Specifically, the grating vectors of the coupling-in grating 221, the fifth extended grating 28, the sixth extended grating 29, the fourth coupling-out grating 234, and the fifth coupling-out grating 235 satisfy the following relationships (6) to (7): KinGB+KepeGB+KocGB=0(6).

[0086] KinR+KepeR+KocR=0(7).

[0087] KinGB and KinR are the grating vectors of the coupled grating 221 corresponding to green-blue light and red light, respectively; KepeGB is the grating vector of the fifth extended grating 28; KepeR is the grating vector of the sixth extended grating 29; KocGB is the grating vector of the fourth coupled grating 234; and KocR is the grating vector of the fifth coupled grating 235.

[0088] Equations (6) and (7) above provide clear constraints for the design of each grating parameter. Their physical significance lies in the fact that by precisely matching and coordinating the vectors of the input grating, extended grating, and output grating, red and blue-green light, although incident from different input gratings and guided by different extended grating paths, can have their propagation directions modulated to meet the output requirements when propagating to their respective fourth and fifth output gratings 234 and 235. This design ensures that light of different colors, after propagating through independent paths within the waveguide, can still achieve precise pixel-level synthesis in space, thereby optically avoiding color shift and aberrations, and significantly improving the color purity and visual uniformity of the final output image.

[0089] Example 4 The coupling grating assembly 22 includes a coupling grating 221, which corresponds to multiple optomechanical units 12 and is used to receive light emitted from the multiple optomechanical units 12. That is, a single coupling grating 221 is disposed in the coupling region of the waveguide substrate 21 and is spatially aligned with multiple (e.g., two or three) optomechanical units 12.

[0090] The single coupling grating assembly 22 described here is not a traditional single-period, single-function diffraction element, but a specially designed multifunctional coupling grating 221. Specifically, the coupling grating 221 is designed to possess wavelength sensitivity and / or angle sensitivity. The working principle of the coupling grating 221 is as follows: Since multiple optomechanical units 12 are arranged side-by-side with a small spacing or at a specific angle in space, the light beams emitted to the waveguide coupling region are parallel to each other or have a definite angular relationship, but their incident points or incident directions differ. This multifunctional grating, by integrating microstructures with different grating vectors such as different periods, orientations, or modulation profiles in a local area, or by designing angle and wavelength selectivity characteristics like a volume holographic grating, enables it to produce differentiated responses to light with different incident positions, different incident angles, or different wavelengths.

[0091] Therefore, when red, green, and blue light from different optomechanical units 12 are incident on the region of the single coupling grating 221 in a specific spatial-angular distribution, the coupling grating 221 can selectively couple different colors of light into the optical waveguide 20 in a way that is efficient and meets the requirements for subsequent propagation.

[0092] This application embodiment also provides a method for manufacturing an optical display system 100, which includes the following steps.

[0093] S30. A lens barrel 11 and a plurality of optical engine units 12 are provided. The optical engine units 12 are encapsulated in the lens barrel 11 to form an optical engine module 10. The plurality of optical engine units 12 are used to generate image light of different colors respectively.

[0094] The encapsulation here refers not only to mechanically fixing the optomechanical unit 12 within the shared lens barrel 11, but more importantly, to ensuring that the optical axes of each unit maintain a precise parallel or preset angular relationship with the reference plane of the lens barrel 11, thereby achieving the design requirement of mutual optical axis parallelism. In addition to providing structural support and protection, the inner wall of the lens barrel 11 and / or the sidewalls of the optomechanical unit 12 are typically treated with light-absorbing materials (such as a black matte coating) to suppress internal stray light and improve imaging contrast. This integrated encapsulation transforms the originally independent multiple imaging systems into a physically extremely compact module, laying a solid foundation for subsequent system-level integration with waveguides.

[0095] S40. Provide an optical waveguide 20, the optical waveguide 20 including a waveguide substrate, a coupling grating assembly 22 and a coupling grating assembly 23, the coupling grating assembly 22 being disposed on the coupling region of the waveguide substrate, and the coupling grating assembly 23 being disposed on the coupling region of the waveguide substrate.

[0096] The waveguide substrate 21 is typically made of a high refractive index material (such as glass or SiC) to support large-angle total internal reflection. The coupling grating assembly 22 and the coupling grating assembly 23 can be fabricated on the surface or inside of the waveguide substrate through processes such as nanoimprinting, photolithography, or holographic recording. Their types can be surface relief gratings, metasurface structures, or volume holographic gratings.

[0097] S50. The optomechanical module 10 is configured to couple the input grating assembly 22 of the optical waveguide 20. The input grating assembly 22 is used to couple the image light from the plurality of optomechanical units 12 into the interior of the waveguide substrate. The output grating assembly 23 is used to combine the image light of different colors transmitted on the waveguide substrate into color image light and couple it out.

[0098] Specifically, the optomechanical module 10 needs to be precisely fixed so that the image beams emitted by each optomechanical unit 12 are incident on the coupling region of the waveguide at the optimal angle. The coupling grating assembly 22 is responsible for efficiently and selectively coupling the multicolor light from different optomechanical units 12 into the interior of the waveguide substrate 21; the coupling grating assembly 23 is responsible for spatially combining the multicolor light after conduction and possible expansion within the waveguide, and finally outputting a complete color image light beam.

[0099] In some alternative embodiments, providing a plurality of optomechanical units 12 includes the following steps.

[0100] S31. Provide multiple wafers, and process optical functional layers 1221 on each of the wafers respectively.

[0101] The optical functional layer 1221 refers to a microstructure layer with specific optical functions formed on a wafer through semiconductor processes (such as photolithography, etching, nanoimprinting, etc.). Each layer can be fabricated as a wafer-level optical lens, a diffractive optical element, or a metasurface structure, respectively undertaking different functions such as beam collimation, aberration correction, and beam shaping.

[0102] S32. Multiple optical functional layers 1221 are aligned and bonded using a wafer bonding process to form a projection lens 122.

[0103] Bonding processes can include thermoforming, anodic bonding, or adhesive bonding. Through high-precision wafer-level alignment and bonding, the optical functional layers 1221 on multiple wafers are integrated in a single step into a multi-layered, monolithic lens structure, i.e., a multi-layered lens stack. This fabrication method eliminates the traditional process of independent grinding, molding, and manual assembly of lenses, achieving extreme thinness and miniaturization of the lens while ensuring extremely high inter-unit consistency and surface accuracy. It is the core technology for large-scale, low-cost production.

[0104] S33, Provide at least two image sources 121 for generating light of different colors. For example, a red micro-light-emitting diode chip, a blue-green micro-light-emitting diode chip, or a laser diode array.

[0105] S34. The image source 121 and the corresponding optical path in the projection lens 122 are matched one-to-one to form an optical engine unit 12.

[0106] Each image source 121 needs to be aligned with the optical axis and focal plane of its corresponding projection lens 122 to ensure that the image light is correctly received and processed by the lens. Finally, these optical engine units 12, which integrate the image source 121 and the projection lens 122, are packaged into the lens barrel 11 in the manner described above to complete the fabrication of the optical engine module 10.

[0107] According to the above-mentioned method for manufacturing the optical display system 100, the advantage lies in combining wafer-level optics with semiconductor integration technology, and combining the parallel architecture of multiple optomechanical units with the system-level color mixing design of waveguide gratings through a process that can be mass-produced, thereby systematically producing augmented reality optical display systems 100 that are small in size, light in weight, have high luminous efficiency, good color and controllable cost.

[0108] This application also provides a near-eye display device, which includes the optical display system 100 described in any of the above embodiments, or includes the optical display system 100 prepared by the aforementioned preparation method.

[0109] Near-eye display devices are head-mounted devices that optically overlay computer-generated virtual images onto real-world scenes observed by the user, thereby achieving an augmented reality visual experience. Common forms include, but are not limited to, AR glasses and AR helmets. The core function of such devices is to serve as a carrier of information, providing clear, realistic digital content that blends seamlessly with the real environment without obstructing the user's normal field of vision.

[0110] In addition to the optical display system 100, the near-eye display device also includes a frame and temples, and a control and power supply module.

[0111] The frame and temples constitute the main support structure and external form of the near-eye display device. The frame can be used to house and fix the optical display system 100 and keep it stable in the best viewing position in front of the user's eyes, while the temples extend to the user's ears to provide wearing support, and their internal space is often used to integrate electronic components or batteries.

[0112] The control and power supply module includes a processor, memory, sensors (such as IMU and camera), wireless communication unit and power management system, etc. It is responsible for driving the image source 121 (such as µLED) in the optomechanical module 10 to generate image signals, processing environmental interaction data, and providing stable power to the entire near-eye display device.

[0113] In this embodiment, the optical display system 100 is integrated inside the frame or temple of the near-eye display device. The combination of the optomechanical module 10 and the optical waveguide 20 constitutes the optical imaging backbone of the near-eye display device. Specifically, the optomechanical module 10 serves as a miniature image generation unit. The image light emitted from it is transmitted, expanded, and synthesized through the optical waveguide 20, which is made into a lens shape and is also called a waveguide lens. Finally, at a certain distance in front of the user's eyes, such as at the virtual image distance, a magnified color image is formed and blended with the real external scene.

[0114] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0115] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0116] The optical display system and its fabrication method, as well as the near-eye display device, provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An optical display system, characterized in that, include: An optical engine module, comprising a lens barrel and at least two optical engine units, each of the optical engine units being used to generate image light of a certain color, and different optical engine units generating image light of different colors; An optical waveguide, comprising a waveguide substrate, a coupling grating assembly disposed in a coupling region of the waveguide substrate, and a coupling grating assembly disposed in a coupling out region of the waveguide substrate. The optomechanical module is disposed on one side of the coupling region of the optical waveguide, and the coupling grating assembly is used to couple image light from multiple optomechanical units into the waveguide substrate; the coupling grating assembly is used to combine image light of different colors transmitted on the waveguide substrate into color image light and couple it out.

2. The optical display system according to claim 1, characterized in that, Each of the optical-mechanical units includes an image source and a projection lens. The projection lens is correspondingly disposed on the light-emitting side of the image source. The projection lens includes a plurality of optical functional layers arranged in sequence. Each optical functional layer is one of a wafer-level optical lens, a diffractive optical element, and a metasurface structure.

3. The optical display system according to claim 1, characterized in that, The inner wall of the lens barrel and / or the side wall of the optical engine unit are made of light-absorbing material or coated with a light-absorbing coating.

4. The optical display system according to claim 1, characterized in that, The optical axes of the optical-mechanical units are parallel to each other.

5. The optical display system according to any one of claims 1 to 4, characterized in that, The number of the optomechanical units is three, which are used to generate red, green and blue image light respectively; the coupling grating assembly includes three coupling gratings, which correspond one-to-one with the three optomechanical units.

6. The optical display system according to claim 5, characterized in that, The optical waveguide further includes a first extended grating and a second extended grating disposed on the waveguide substrate; the coupling grating assembly includes a first coupling grating and a second coupling grating; Specifically, green light from the green optomechanical unit is coupled into the corresponding insertion grating and then guided to the first output grating by the first extended grating; red light from the red optomechanical unit is coupled into the corresponding insertion grating and then guided to the second output grating by the second extended grating; and blue light from the blue optomechanical unit is coupled into the corresponding insertion grating and then coupled out by both the first output grating and the second output grating.

7. The optical display system according to claim 6, characterized in that, The grating vectors of the plurality of coupled-in gratings, the first extended grating, the second extended grating, the first coupled-out grating, and the second coupled-out grating satisfy the following relationship: KinG+KepeG+KocG=0(1); KinR+KepeR+KocR=0(2); KinB+KocG+KocR=0(3); Wherein, KinG, KinR, and KinB are the grating vectors of the coupled gratings corresponding to green light, red light, and blue light, respectively; KepeG is the grating vector of the first extended grating, and KepeR is the grating vector of the second extended grating; KocG is the grating vector of the first coupled-out grating, and KocR is the grating vector of the second coupled-out grating.

8. The optical display system according to any one of claims 1 to 4, characterized in that, The number of the optomechanical units is two, including a red optomechanical unit for generating red light and a blue-green optomechanical unit for generating blue-green composite light; the coupling grating assembly includes two coupling gratings, corresponding to the red optomechanical unit and the blue-green optomechanical unit respectively; the optical waveguide also includes a third extended grating and a fourth extended grating; the coupling grating assembly includes a third coupling grating; Wherein, the blue-green light from the blue-green optomechanical unit is coupled into the corresponding coupled-in grating and then guided out by the third extended grating to the third coupled-out grating; the red light from the red optomechanical unit is coupled into the corresponding coupled-in grating and then guided out by the fourth extended grating to the third coupled-out grating.

9. The optical display system according to claim 8, characterized in that, The grating vectors of the coupled-in grating, the third extended grating, the fourth extended grating, and the third coupled-out grating satisfy the following relationship: KinGB+KepeGB+Koc=0(4); KinR+KepeR+Koc=0(5); Wherein, KinGB and KinR are the grating vectors of the coupled grating components corresponding to green-blue light and red light, respectively; KepeGB is the grating vector of the third extended grating, and KepeR is the grating vector of the fourth extended grating; Koc is the grating vector of the third coupled-out grating.

10. The optical display system according to any one of claims 1 to 4, characterized in that, The coupling grating assembly includes a coupling grating, which corresponds to multiple optomechanical units and is used to receive light emitted from the multiple optomechanical units.

11. A method for fabricating an optical display system, characterized in that, The method for preparing the optical display system according to any one of claims 1 to 10 includes: A lens barrel and multiple optical-mechanical units are provided, and the optical-mechanical units are encapsulated in the lens barrel to form an optical-mechanical module. The multiple optical-mechanical units are used to generate image light of different colors respectively. An optical waveguide is provided, the optical waveguide including a waveguide substrate, a coupling grating assembly and a coupling grating assembly, the coupling grating assembly being disposed on the coupling region of the waveguide substrate, and the coupling grating assembly being disposed on the coupling region of the waveguide substrate; The optomechanical module is configured to couple the image light from the plurality of optomechanical units into the interior of the waveguide substrate. The coupling grating assembly is used to couple the image light from the plurality of optomechanical units into the interior of the waveguide substrate. The coupling grating assembly is used to combine the image light of different colors transmitted on the waveguide substrate into a color image light and couple it out.

12. The method for fabricating an optical display system according to claim 11, characterized in that, The method of fabricating multiple optomechanical units includes: Multiple wafers are provided, and an optical functional layer is formed on each of the wafers respectively; Multiple optical functional layers are aligned and bonded using a wafer bonding process to form a projection lens; Provide at least two image sources, each used to generate light of different colors; The image source is matched one-to-one with the corresponding optical path in the projection lens to form an optomechanical unit.

13. A near-eye display device, characterized in that, Includes the optical display system according to any one of claims 1 to 10; or includes the optical display system prepared by the method for preparing the optical display system according to claim 11 or 12.

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