Diffractive optical structures and myopia indicators

Abstract

Provision of diffractive optical structures and myopia indicator devices. [Solution] The substrate includes an input / output coupling region, the output coupling region includes a plurality of periodically arranged lattice ridges and lattice grooves between adjacent lattice ridges, the lattice grooves are filled with materials of at least two different refractive indices, and the average refractive index of the different materials within the lattice unit period is JPEG2026070473000101.jpg75 JPEG2026070473000102.jpg942 JPEG2026070473000103.jpg1641 Here V1~V m These represent the volume or area of ​​materials of types 1 to m, respectively, n1 to n m These are the refractive indices of materials of types 1 to m, respectively, V unitcell This is the volume or area of ​​the unit period of the lattice.

Description

[Technical Field]

[0001] This application belongs to the field of augmented reality (AR) technology, and more specifically, relates to diffractive optical structures and myopia display devices. [Background technology]

[0002] With the rapid development of augmented reality (AR) technology, AR optical schemes based on diffracted optical waveguides are gradually becoming an important method for realizing highly efficient and lightweight display systems. In this field, the overall optical efficiency of a waveguide is one of the important indicators for evaluating its performance. In conventional technology, the ability to control the diffraction efficiency in the non-input coupling region has been a key factor limiting further improvement of waveguide efficiency.

[0003] Therefore, how to effectively improve the diffraction efficiency control capability in the non-input coupling region and achieve flexible control of the lattice diffraction efficiency curve is an urgent issue that needs to be resolved in current AR optics solutions. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The object of this application is to provide a new technical solution for diffractive optical structures and myopia display devices. [Means for solving the problem]

[0005] According to a first aspect of the present application, an embodiment of the present application provides a diffractive optical structure comprising a substrate and an input coupling region and an output coupling region placed on the substrate. Here, the output coupling region includes a lattice structure comprising a plurality of periodically arranged lattice ridges and lattice grooves between adjacent lattice ridges, wherein the lattice grooves employ materials with at least two different refractive indices. The average value of the refractive indices of different materials within the lattice unit period of the aforementioned lattice structure is: The file is JPEG2026070473000002.jpg75, and JPEG2026070473000003.jpg942, JPEG2026070473000004.jpg2041, here, V1~V m These represent the volume or area of ​​each material from type 1 to type m, n1 to n m These are the refractive indices of materials from type 1 to type m, respectively, and V unitcell This is the volume or area of ​​the unit period of the lattice.

[0006] Selectively, the average value of the refractive indices of different materials within the lattice unit period of the lattice structure. JPEG2026070473000005.jpg75 is, The file is JPEG2026070473000006.jpg855.

[0007] Selectively, the substrate includes two opposing surfaces, and the input coupling region and the output coupling region are located on at least one surface of the substrate. The input coupling region is used to input coupling an external light ray into the interior of the substrate. The aforementioned output coupling region is used to combine the light rays by dilating the pupil.

[0008] Selectively, the lattice structure includes a plurality of lattice ridges arranged along a first direction according to a first period P1, with the lattice grooves between any two adjacent lattice ridges, where at least a portion of the lattice grooves is an air groove. The average value of the refractive index of different materials within the periodicity of the lattice unit of the aforementioned lattice structure. JPEG2026070473000007.jpg75 is as follows: JPEG2026070473000008.jpg2040, Here, JPEG2026070473000009.jpg12122, V1 is the cross-sectional area of the lattice ridge, n1 is the refractive index of the lattice ridge, V2 is the cross-sectional area of the air groove, n2 is the refractive index of air, V3 is the cross-sectional area of the first type of filling material filled in the lattice groove, n3 is the refractive index of the first type of filling material filled in the lattice groove, V m is the cross-sectional area of the m-th type of filling material filled in the lattice groove, n m is the refractive index of the m-th type of filling material filled in the lattice groove, V unitcell =P1*H, where H is the height of the lattice ridge.

[0009] Optionally, the lattice structure includes a plurality of lattice ridges, the plurality of lattice ridges are arranged at intervals of a second period P2 along a second direction and at intervals of a third period P3 along a third direction, there is a lattice groove between any two adjacent lattice ridges, and at least a part of the lattice groove is an air groove. The average value of the refractive indices of different materials within the lattice unit period of the lattice structure JPEG2026070473000010.jpg75 is as follows: JPEG2026070473000011.jpg1948, JPEG2026070473000012.jpg11134, V1 is the volume of the lattice ridge, n1 is the refractive index of the lattice ridge, V2 is the volume of the air groove, n2 is the refractive index of air, V3 is the volume of the first type of filling material filled in the lattice groove, n3 is the refractive index of the first type of filling material filled in the lattice groove, V m is the volume of the m-th type of filling material filled in the lattice groove, n m is the refractive index of the m-th type of filling material filled in the lattice groove, V unitcell =(P2*P3)*H, where H is the height of the lattice ridge.

[0010] Optionally, at least one layer of filling material is coated on the grating structure, and the refractive index of the filling material is different from that of the grating ridge.

[0011] Optionally, the at least one layer of filling material includes a first type of filling material coated on the surface of the grating ridge, the groove wall and the groove bottom of the grating groove, where the grating groove includes an air groove and the first type of filling material.

[0012] Optionally, the at least one layer of filling material further includes a second type of filling material, the second type of filling material is coated on the first type of filling material, the grating groove further includes the second type of filling material, and at the same time, the air groove is retained, where the refractive indices of the first type of filling material and the second type of filling material are different.

[0013] Optionally, the at least one layer of filling material further includes a third type of filling material coated on the surface of the second type of filling material away from the first type of filling material, and the inside of the grating groove further includes the third type of filling material filling the air groove. Here, the refractive indices of the first type of filling material, the second type of filling material, and the third type of filling material are different from each other.

[0014] According to the second aspect of the present application, the embodiments of the present application provide a near-eye display device, and the near-eye display device includes an image source, and the diffractive optical structure described in the first aspect, and the light beam emitted from the image source can be incident on the input coupling region on the diffractive optical structure.

Advantages of the Invention

[0015] One beneficial effect of the embodiments of the present application is as follows: The diffractive optical structure according to the embodiments of the present application is the average value of the refractive indices of different materials within the grating unit period of the grating structure in the output coupling region (i.e., the non-input coupling region). By controlling the range of JPEG2026070473000013.jpg75, precise control of the movement of the diffraction efficiency curve of the lattice structure is achieved, and this design can significantly improve the overall output coupling efficiency of the diffractive optical structure. Specifically, in the process in which a light ray undergoes total internal reflection along the interior of the substrate and is transmitted stepwise to the trailing end, the reflection angle of the light ray naturally decreases, and this application, through careful design, controls the average value of the refractive indices of different materials within the lattice unit period of the lattice structure within the output coupling region. By reducing JPEG2026070473000014.jpg75 in a timely manner, it is possible to flexibly shift the peak value of the output coupling efficiency curve in the small angular direction, and accurately match the output coupling requirements of light rays at small angles.

[0016] The technical solution provided by the embodiment of this application not only overcomes the challenge of precisely controlling the shape and peak value position of the output coupling efficiency curve at different locations in conventional methods, but also precisely positions the peak value of the output coupling efficiency curve at the position of the minimum reflection angle of the light ray, thereby significantly optimizing the transmission path and output coupling efficiency within the diffractive optical structure of the light ray.

[0017] Other features and advantages of the present invention will become apparent by describing in detail exemplary embodiments of the present invention with reference to the following drawings. [Brief explanation of the drawing]

[0018] The drawings incorporated into the specification and constituting part of the specification are used to illustrate embodiments of the present application and to explain the principles of the present application together with their descriptions. [Figure 1] This is a schematic diagram of the diffractive optical structure according to an embodiment of the present invention. [Figure 2] This is one schematic diagram of the lattice structure of the output coupling region according to an embodiment of the present invention. [Figure 3] This is one of the output coupling efficiency curves of a diffractive optical structure according to an embodiment of the present invention. [Figure 4] This is the second output coupling efficiency curve of the diffractive optical structure according to the embodiment of the present invention. [Figure 5]This is the output coupling efficiency curve of the diffractive optical structure according to the embodiment of the present invention. [Figure 6] This is a schematic diagram of the lattice structure of the output coupling region according to the embodiment of the present invention. [Figure 7] This is the fourth output coupling efficiency curve of the diffractive optical structure according to the embodiment of the present invention. [Figure 8] This is a schematic diagram of the lattice structure of the output coupling region according to the embodiment of the present invention. [Figure 9] This is schematic diagram 4 of the lattice structure of the output coupling region according to the embodiment of the present invention. [Figure 10] Figure 5 shows a schematic diagram of the lattice structure of the output coupling region according to the embodiment of the present invention. [Figure 11] This is a schematic diagram of the lattice structure of the output coupling region according to the embodiment of the present invention. [Figure 12] This is schematic diagram 7 of the lattice structure of the output coupling region according to the embodiment of the present invention. [Figure 13] This is a schematic diagram of the lattice structure of the output coupling region according to the embodiment of the present invention. [Modes for carrying out the invention]

[0019] Now, various exemplary embodiments of the present application will be described in detail with reference to the attached drawings. It should be noted that the relative arrangements of the components and steps, numerical formulas, and numerical values ​​described in these embodiments do not limit the scope of the present application unless otherwise specified.

[0020] In the following description, at least one exemplary embodiment is provided for illustrative purposes only and is not intended to limit the present application or its application or use.

[0021] Techniques, methods, and apparatus known to those skilled in the art will not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification.

[0022] In all the examples presented and discussed herein, any specific values ​​should be interpreted as merely illustrative and not limiting. Therefore, other examples of the illustrative embodiments may have different values.

[0023] It should be noted that similar symbols and letters indicate the same items in the following drawings, and therefore, if an item is defined in one drawing, there is no need to discuss it further in subsequent drawings.

[0024] In the following, the diffractive optical structure and myopia indicator device according to the embodiment of this application will be described in detail with reference to the attached drawings.

[0025] In diffractive optical structures, diffractive optical waveguides are a common form, and hereafter, diffractive optical waveguides will be abbreviated as optical waveguides.

[0026] The overall optical efficiency of an optical waveguide is mainly composed of two parts: input coupling efficiency and pupil dilation output coupling efficiency. Input coupling efficiency primarily focuses on how efficiently external rays are input-coupled into the optical waveguide, while pupil dilation output coupling efficiency is more complex and requires precise output coupling control for rays at different angles and locations. Unlike input coupling efficiency, which pursues the principle that higher is better, pupil dilation output coupling efficiency needs to achieve effective output coupling of rays at different angles and locations as required by practical needs. At the leading edge of the output coupling region, the transmission path of rays is relatively short and rays with relatively large total reflection angles are dominant, so the peak of the output coupling efficiency curve in this region is generally at a large angular position. However, as rays are transmitted to the trailing end of the optical waveguide, their transmission path lengthens and the total reflection angle gradually decreases, requiring the output coupling efficiency curve to adjust its peak value position accordingly to satisfy the output coupling requirements of rays at small angles. However, existing methods for controlling pupil dilation output coupling face many challenges in achieving this control, making it difficult to accurately control the shape and peak position of the output coupling efficiency curve at different locations. Therefore, this invention proposes a new diffractive optical structure design, which will be described in detail below.

[0027] According to one embodiment of the present application, a diffractive optical structure is provided, referring to Figure 1, the diffractive optical structure includes a substrate 3 and an input coupling region 1 and an output coupling region 2 placed on the substrate 3, wherein the output coupling region 2 includes a lattice structure comprising a plurality of periodically arranged lattice ridges 201 and lattice grooves 202 between adjacent lattice ridges 201, the lattice grooves 202 employing materials with at least two different refractive indices, and the average value of the refractive indices of the different materials within the lattice unit period of the lattice structure is The file is JPEG2026070473000015.jpg75, and JPEG2026070473000016.jpg942, JPEG2026070473000017.jpg1641, here, V1~V m These represent the volume or area of ​​each material from type 1 to type m, n1 to n mThese are the refractive indices of materials from type 1 to type m, respectively, and V unitcell This is the volume or area of ​​the unit period of the lattice.

[0028] The design of the diffractive optical structure according to the embodiment of the present application, with reference to Figure 1, comprises a substrate 3 and an input coupling region 1 and an output coupling region 2 placed thereon, and the design in the present application is the average value of the refractive indices of different materials within the period of the lattice unit of the lattice structure placed within the output coupling region 2. Efficient light ray output coupling is achieved by controlling JPEG2026070473000018.jpg75. For example, JPEG2026070473000019.jpg942.

[0029] The diffractive optical structure according to the embodiment of this application includes the following parts, which will be specifically described below.

[0030] Substrate 3: As a fundamental support layer for the entire diffractive optical structure, it provides a stable platform for the input coupling region 1 and the output coupling region 2. The substrate 3 has good optical transparency and mechanical stability, ensuring effective transmission of light rays and overall structural stability.

[0031] Input coupling region 1: The main function of this region is to effectively couple external light rays to the substrate 3, and it corresponds to the entrance where the light rays enter the diffractive optical structure.

[0032] Output coupling region 2: This region includes a specially designed lattice structure that outputs the light ray into the diffractive optical structure by pupil dilation (i.e., increasing the beam diameter) and coupling it to the external space. In this application, this represents a crucial part of achieving efficient ray utilization.

[0033] In the diffractive optical structure according to the embodiment of the present application, referring to Figures 1 and 2, the output coupling region 2 includes a specially designed lattice structure, which consists of a plurality of periodically arranged lattice ridges 201 and lattice grooves 202 between adjacent lattice ridges, where the average value of the refractive indices of different materials within the lattice unit period of the lattice structure. Design JPEG2026070473000020.jpg75 (for example, By designing it as JPEG2026070473000021.jpg942, the diffraction efficiency curve of the lattice structure can be affected, and more efficient output coupling of light rays can be achieved.

[0034] Here, the lattice groove 202 can be filled with at least two materials, such as air and at least one low refractive index material. When the lattice groove 202 is completely filled with air, the average refractive index of the different materials within the lattice unit period of the lattice structure JPEG2026070473000022.jpg75 is version 1.1.

[0035] Average value of refractive index of lattice structure To achieve control of JPEG2026070473000023.jpg75, this application proposes several methods, referring to Figures 2 and 6, including introducing air and / or other low refractive index materials into the lattice grooves 202.

[0036] For example, various process methods such as spin-coat filling adhesives, inkjet filling adhesives, ALD deposition, PVD deposition, and CVD deposition can be used. By using these methods alone or in combination to adapt to the requirements of output coupling of light rays at different angles, the average refractive index of the lattice structure at different positions can be obtained. JPEG2026070473000024.jpg75 can be adjusted to improve the output coupling efficiency and ray uniformity of the overall optical diffraction structure.

[0037] Based on the diffractive optical structure according to the embodiment of the present invention, its core is a special design of the lattice structure within the output coupling region 2, and the average value of the refractive indices of different materials within its lattice unit period. JPEG2026070473000025.jpg75 is set to the range of 1.1 to 2.4 mentioned in the above example. This design utilizes the ability to adjust the physical parameters of the lattice structure and the average refractive index of different materials within the lattice unit period. This enables fine-grained control over JPEG2026070473000026.jpg75.

[0038] Specifically, by adjusting the size (e.g., area or volume) and refractive index of the lattice ridges 201 and lattice grooves 202, and by introducing air or other materials with a lower refractive index, the average refractive index of different materials within the lattice unit period of the lattice structure can be adjusted. The JPEG2026070473000027.jpg75 can be flexibly modified. This design not only broadens the control range but also allows for flexible adjustment of the shape and position of the lattice diffraction efficiency curve as needed, thereby optimizing the output coupling efficiency and uniformity of the light rays.

[0039] This type of diffractive optical structure not only improves the efficiency of light utilization but also enhances the overall performance of the diffractive optical structure, resulting in a clearer and more uniform visual experience for nearsighted display devices.

[0040] The diffractive optical structure according to the embodiment of the present invention can provide at least the following technical effects by newly designing the lattice structure of the output coupling region 2 thereon.

[0041] First, the average value of the refractive indices of different materials within the lattice unit period of the lattice structure in output coupling region 2. JPEG2026070473000028.jpg75 By optimizing for JPEG2026070473000029.jpg942, the diffractive optical structure according to the embodiment of the present invention can significantly improve the output coupling efficiency of the light ray. This is because, as the reflection angle of the light ray naturally decreases during the process in which the light ray is input coupled from the input coupling region 1 into the substrate 3 and transmitted to the output coupling region 2 (i.e., the rear end), By appropriately reducing the value of JPEG2026070473000030.jpg75, it is possible to ensure that the peak of the output coupling efficiency curve shifts to a smaller angular direction, thereby satisfying the requirement for efficient output coupling of rays at different positions and angles.

[0042] Next, within the entire output coupling region 2, the average value of the refractive indices of different materials within the lattice unit period of the lattice structure. By achieving rational control of JPEG2026070473000031.jpg75, the diffractive optical structure of the present invention can improve the uniformity distribution of light rays and reduce light ray loss or distortion due to non-uniformity of the lattice structure.

[0043] Therefore, the diffractive optical structure according to the embodiment of the present invention not only improves the output coupling efficiency by designing new optical parameters for the lattice structure within the output coupling region 2, but also significantly improves the overall optical performance of the diffractive optical structure by further reinforcing the uniformity of the light rays.

[0044] The diffractive optical structure according to the embodiment of this application is the average value of the refractive indices of different materials within the periodicity of the lattice unit of the lattice structure in the output coupling region (non-input coupling region). By controlling JPEG2026070473000032.jpg75, precise control of the diffraction efficiency curve of the lattice structure is achieved, and this design can improve the overall output coupling efficiency of the optical structure. Specifically, in the process in which a light ray undergoes total internal reflection along the interior of the substrate and is transmitted stepwise to the trailing end, the reflection angle of the light ray naturally decreases, and this application, through careful design, controls the average refractive index of different materials within the lattice unit period of the lattice structure in the output coupling region. By reducing JPEG2026070473000033.jpg75 in a timely manner, it is possible to ensure that the peak value of the output coupling efficiency curve can be flexibly shifted in the small angular direction, and that it can accurately match the output coupling requirements of light rays at small angles.

[0045] The technical solution provided by the embodiment of this application not only overcomes the challenge of precisely controlling the shape and peak value position of the output coupling efficiency curve at different locations in conventional methods, but also precisely positions the peak value of the output coupling efficiency curve at the position of the minimum reflection angle of the light ray, thereby significantly optimizing the transmission path and output coupling efficiency within the diffractive optical structure of the light ray.

[0046] In some examples of this application, the average value of the refractive indices of different materials within the lattice unit period of the lattice structure. JPEG2026070473000034.jpg75 is, The file is JPEG2026070473000035.jpg959.

[0047] In the present example, within the output coupling region 2, the average value of the refractive indices of different materials within the lattice unit period of the lattice structure JPEG2026070473000036.jpg75 is, This is limited to JPEG2026070473000037.jpg855. The design in this range is based, on the one hand, on adjustments when using a low refractive index material for the lattice ridge 201, and on the other hand, on optimization considering the optical performance of the lattice structure.

[0048] Specifically, the average value of the refractive indices of different materials within the lattice unit period of the aforementioned lattice structure. The range for JPEG2026070473000038.jpg32 is designed to be between 1.35 and 2.15 (including the two endpoint values ​​of 1.35 and 2.15), which is the average value of the refractive index when designing the lattice structure. This means more precise control over JPEG2026070473000039.jpg75. This refers to the average value of the refractive index within this range. JPEG2026070473000040.jpg75 can be effectively matched with the requirements for light ray transmission characteristics and output coupling, thereby ensuring efficient output coupling of light rays at different positions and angles.

[0049] Within the range proposed in this example of the present application, the shape and peak position of the lattice diffraction efficiency curve can be controlled more precisely by adjusting the physical parameters of the lattice structure, such as the size of the lattice ridges 201 and lattice grooves 202 and the refractive index of the filling material. In particular, it is possible to ensure that the peak value of the output coupling efficiency curve can reach an optimal position even at different angles during the transmission of light rays from the input coupling region 1 to the trailing end, thereby significantly improving the output coupling efficiency.

[0050] The range proposed in this example of the present application not only helps to improve the output coupling efficiency but can also improve the uniformity distribution of light rays and reduce light ray loss. The average value of the refractive indices of different materials within the lattice unit period of the lattice structure in the output coupling region 2. Because JPEG2026070473000041.jpg75 is precisely controlled, the transmission path of light rays within the substrate 3 of the diffractive optical structure becomes more stable, reducing scattering and reflection of light rays due to changes in refractive index. This not only improves the utilization rate of light rays but also makes the expression of the optical performance of the diffractive optical structure more stable and reliable.

[0051] In some examples of the present application, referring to Figure 1, the substrate 3 includes two opposing surfaces, the input coupling region 1 and the output coupling region 2 are located on at least one surface of the substrate 3, the input coupling region 1 is used to input couple an external ray into the interior of the substrate 3, and the output coupling region 2 is used to output couple a ray by dilating its pupil.

[0052] In one specific example, referring to Figure 1, the input coupling region 1 and the output coupling region 2 are both located on one of two opposing surfaces of the substrate 3, and the input coupling region 1 and the output coupling region 2 are located adjacent to each other with a gap between them, and within the output coupling region 2, the lattice structure is located along the direction away from the input coupling region 1, and the average value of the refractive index of different materials within the lattice unit period JPEG2026070473000042.jpg75, for example, exhibits a tendency to gradually decrease in quality.

[0053] The specific analysis of the design in the above example is as follows:

[0054] (1) Efficient transmission in the initial stages: With respect to the lattice structure located within the output coupling region 2, the lattice structure closer to the input coupling region 1 has a high average value of refractive index It may be set to have JPEG2026070473000043.jpg75. This design takes into account the optical properties and requirements when light rays first enter the diffracting optical structure. High average refractive index JPEG2026070473000044.jpg75 helps to enhance the stability and transmission efficiency of the light ray in its initial stages, ensuring that the light ray enters the interior of the substrate 3 smoothly from the input coupling region 1 and propagates along a predetermined path.

[0055] (2) Within the output coupling region 2, match output coupling requests at different locations: As the light ray is transmitted to the trailing edge within the substrate 3, the reflection angle gradually decreases. To optimize the output coupling efficiency, the lattice structure within the output coupling region 2 has an average refractive index that gradually decreases. The design may also adopt JPEG2026070473000045.jpg75, thereby achieving more accurate and efficient output coupling of light rays at different positions and angles. In particular, at positions far from the input coupling region 1, the average value of a low refractive index JPEG2026070473000046.jpg75 ensures that efficient output coupling can be achieved even when the light rays have a small reflection angle.

[0056] (3) The efficiency of optical transmission and output coupling can be well optimized: Within the entire output coupling region 2, the average value of the refractive index of the lattice structure The gradient change design of JPEG2026070473000047.jpg75 not only improves the transmission stability of light rays within the diffractive optical structure but also significantly optimizes the overall output coupling efficiency. By precisely controlling the physical parameters and refractive index distribution of the lattice structure, the diffractive optical structure of this application achieves precise control of the light ray transmission path and output coupling angle, allowing the light ray to maintain high transmission efficiency and output coupling efficiency over the entire length range of the substrate 3.

[0057] Overall, within the output coupling region 2, the average value of the refractive index of the lattice structure close to the input coupling region 1 is obtained. JPEG2026070473000048.jpg75 is set to a high value to ensure that light rays are transmitted efficiently and stably in the initial stages. The average value of the refractive index of the lattice structure away from the input coupling region 1. JPEG2026070473000049.jpg75 gradually decreases to match the output coupling requirements of light rays at different positions, optimizing overall ray transmission and coupling efficiency.

[0058] In some examples of the present application, referring to Figures 2 and 6, the grid structure includes a plurality of grid ridges 201 arranged along a first direction according to a first period P1, with grid grooves 202 between any two adjacent grid ridges 201, where at least a portion of the grid grooves 202 is an air groove 203. The average value of the refractive index of different materials within the periodicity of the lattice unit of the aforementioned lattice structure. JPEG2026070473000050.jpg75 is as follows: JPEG2026070473000051.jpg1741, Here, JPEG2026070473000052.jpg12123, V1 is the area of ​​the longitudinal cross-section of the lattice ridge 201, n1 is the refractive index of the lattice ridge 201, V2 is the area of ​​the longitudinal cross-section of the air groove 203, n2 is the refractive index of air, V3 is the area of ​​the longitudinal cross-section of the first type of filling material filled in the lattice groove 202, n3 is the refractive index of the first type of filling material filled in the lattice groove 202, V m n is the area of ​​the vertical cross-section of the m-th type filling material that is filled into the grid groove 202, and n m V is the refractive index of the m-th type filling material that is filled into the lattice groove 202. unitcell =P1*H, where H is the height of the lattice ridge 201.

[0059] The lattice structure according to this example is a one-dimensional lattice having a first period P1 in only one direction.

[0060] In the present example, the design of the lattice structure involves filling at least one filler material and introducing air grooves 203 to obtain the average refractive index of different materials within the lattice unit period of the lattice structure. The intention is to enable control over JPEG2026070473000053.jpg75.

[0061] As light rays are transmitted within an optical waveguide, their reflection angle gradually changes. The design of the lattice structure of this invention allows for the use of the average refractive index of different materials within the lattice unit period of the lattice structure, based on the specific position and angle of light transmission. JPEG2026070473000054.jpg75 (Sometimes the average refractive index is used in the text) By adjusting the image (directly abbreviated as JPEG2026070473000055.jpg75), it is possible to shift the peak value of the lattice diffraction efficiency curve to an optimal position, thereby enabling efficient output coupling of light rays.

[0062] Average value of refractive index of lattice structure By precisely controlling the distribution of JPEG2026070473000056.jpg75, the transmission path of light rays within the optical waveguide becomes more stable, improving the utilization rate and uniformity of light ray distribution, while reducing light ray loss.

[0063] Overall, the lattice structure design according to this invention not only improves the output coupling efficiency of light rays but also reinforces the optical stability of the diffractive optical structure. This provides a clearer and more uniform visual experience for myopia display devices such as augmented reality, and meets the complex and varied requirements for light ray transmission and output coupling.

[0064] In one specific example, referring to Figure 2, if the longitudinal cross-sections of both the lattice ridge 201 and the lattice groove 202 are rectangular, and the lattice groove 202 is an air groove 203, then the average value of the refractive index of different materials within the lattice unit period of the lattice structure JPEG2026070473000057.jpg75 is, The image is JPEG2026070473000058.jpg879, where K1 is the width of the lattice ridge 201, n1 is the refractive index of the lattice ridge 201, K2 is the width of the lattice groove 202 (i.e., the air groove 203), and n2 is the refractive index of air.

[0065] The longitudinal cross-sections of the lattice ridge 201 and the lattice groove 202 are designed to be rectangular, and air is used entirely as the filling material for the lattice groove 202, and the manufacturing process of the lattice structure and the average value of the refractive index are... Simplify the calculation for JPEG2026070473000059.jpg75.

[0066] Despite the simplified design, by adjusting the width ratio (i.e., the values ​​of K1 and K2) of the lattice ridges 201 and air grooves 203, the average refractive index of different materials within the lattice unit period of the lattice structure can still be adjusted. JPEG2026070473000060.jpg75 can be effectively controlled. This control capability allows for better matching of different lattice structures with varying light transmission and output coupling requirements, thereby improving overall optical efficiency.

[0067] It should be noted that, in order to introduce the air groove 203, the average value of the refractive index of different materials within the lattice unit period of the lattice structure The reduction in JPEG2026070473000061.jpg75 allows the peak value of the diffraction efficiency curve to be moved to a more appropriate angular position. This helps to achieve more efficient output coupling of rays during ray transmission, especially for small-angle ray transmission and output coupling.

[0068] In another specific example, referring to Figure 6, if the longitudinal sections of the lattice ridge 201 and the lattice groove 202 are both rectangular, and the lattice groove 202 includes at least one filler material (a first type of filler material 204 shown in Figure 6) and an air groove 203, and the longitudinal sections of the filler material and the air groove 203 are also both rectangular, then the average value of the refractive indices of the different materials within the lattice unit period of the lattice structure is: The image is JPEG2026070473000062.jpg8140, where K1 is the width of the lattice ridge 201, n1 is the refractive index of the lattice ridge 201, K2 is the width of the air groove 203 other than the filling material in the lattice groove 202, n2 is the refractive index of air, and K3~K m These are the widths of different filling materials that are filled into the grid grooves 202, respectively, n3 to n m These are the refractive indices of the different filling materials that are filled into the grid grooves 202, respectively.

[0069] Continuing to refer to Figure 6, this design allows for the flexible combination of one or more filler materials and air grooves 203 within the grid grooves 202, and by adjusting the width ratios of the various materials, the average refractive index of different materials within the grid unit period of the grid structure can be adjusted. This enables the control of JPEG2026070473000063.jpg75. This provides convenience for optimizing ray output coupling in different application scenarios. At the same time, this precise control capability helps achieve more efficient and uniform ray output coupling by shifting the peak value of the lattice diffraction efficiency curve to the optimal position.

[0070] Selectively, the refractive index of the filling material in the lattice groove 202 may be the same as that of the lattice ridge 201. This design is equivalent to widening the width of the lattice ridge 201 without changing the overall layout of the lattice structure. This is the average value of the refractive indices of different materials within the lattice unit period of the lattice structure. This provides a new concept for adjusting JPEG2026070473000064.jpg75.

[0071] Of course, the refractive index of the filling material in the lattice groove 202 may be different from that of the lattice ridge 201. In this case, a low refractive index material can be used to fill a portion of the lattice groove 202, while simultaneously maintaining the air groove 203. This is because the refractive index of different materials within the lattice unit period of the lattice structure is the average value of the refractive index of different materials. This is advantageous for reducing the size of JPEG2026070473000065.jpg75.

[0072] The average value of the refractive index of different materials within the periodicity of the lattice unit of the aforementioned lattice structure. To more flexibly control JPEG2026070473000066.jpg75, the refractive indices of the lattice ridges 201 and the lattice grooves 202 can be selected to be different. In this case, by employing a low refractive index material to fill the lattice grooves 202, the average refractive index of the different materials within the lattice unit period of the lattice structure can be obtained. This can significantly reduce the quality of JPEG2026070473000067.jpg75. This differentiated refractive index design reduces the average refractive index. In addition to expanding the control range of JPEG2026070473000068.jpg75, it also allows for more precise control of the output coupling efficiency of light rays at different positions and angles.

[0073] The leading edge of the output coupling region has a characteristic of requiring high output coupling for light rays with a large total reflection angle. In contrast, this application addresses the average value of the refractive index of the lattice structure. We propose a method for shifting the peak value position of the efficiency curve by controlling JPEG2026070473000069.jpg75. Below, the grid structure of this application is analyzed with reference to Figures 3 to 5 and Figure 7.

[0074] 1. Initial stage: At the tip of the output coupling region 2, output coupling is required only for rays with a large total reflection angle; therefore, the peak value position of the output coupling efficiency curve must be set at a large angular position. Referring to Figure 3, the average value of the refractive index of the lattice structure is used to satisfy the output coupling requirement at the tip. By increasing the size of JPEG2026070473000070.jpg75, the peak value of the output coupling efficiency curve can be shifted to a larger angular position.

[0075] In one specific example, the refractive index n1 of the lattice ridge 201 of the lattice structure is 2.4, the refractive index n2 of the lattice groove 202 is 1.4, the duty cycle is 0.75, and the average refractive index is... According to the calculation formula for JPEG2026070473000071.jpg75, the average value of the refractive index The value for JPEG2026070473000072.jpg75 is 2.15. Referring again to Figure 3, in this case, the peak value of the output coupling efficiency curve is located at approximately 59°.

[0076] 2. Intermediate stage: As the light ray is transmitted to the trailing end away from the input coupling region 1, the reflection angle during propagation of the light ray gradually decreases, and the output coupling requirement changes accordingly. To match this change, the average refractive index of the lattice structure of the output coupling region 2 is used. The JPEG2026070473000073.jpg75 needs to be gradually reduced, thereby shifting the peak value of the output coupling efficiency curve to a smaller angle. In this case, the average value of the refractive index of the lattice structure The JPEG2026070473000074.jpg75 can be reduced in size, and by adjusting the duty cycle, the area ratio of the two materials in the lattice structure can be adjusted, reducing the size of the lattice ridge 201, or reducing the refractive index of the lattice ridge 201 or lattice groove 202. When the duty cycle is adjusted to 0.5, the average refractive index... The file JPEG2026070473000075.jpg75 has a value of 1.9.

[0077] Referring again to Figure 4, the peak values ​​of the output coupling efficiency curve are located to the left and right of 57°.

[0078] 3. Rear end stage: When the light ray is transmitted to the last end of the diffractive optical structure, the reflection angle of the light ray is minimized, and in this case, the peak value of the output coupling efficiency curve shifts to the minimum angular position, maximizing the output coupling efficiency of light rays at small angles. In this case, the duty cycle is adjusted to 0.25, and the average refractive index of the lattice structure is also adjusted. Reduce JPEG2026070473000076.jpg75 to 1.65. Referring to Figure 5, the peak value position of the output coupling efficiency curve is at 54°.

[0079] Furthermore, the average value of the refractive indices of different materials within the lattice unit period of the lattice structure of the output coupling region 2. To further reduce JPEG2026070473000077.jpg75, this invention further proposes a method for introducing it into an air channel.

[0080] Because the refractive index of air (the refractive index of air is 1) is much lower than that of other media materials, introducing air as a filler material allows for the average refractive index of different materials within the periodicity of the lattice unit of the lattice structure. The image quality of JPEG2026070473000078.jpg75 can be significantly reduced, and the average value of the refractive index can be reduced. JPEG2026070473000079.jpg75 can be further reduced to 1.35, thereby shifting the peak value of the output coupling efficiency curve to an even smaller angle, ensuring efficient output coupling of the last ray. Referring to Figure 7, the peak value position of the output coupling efficiency curve is at 44° to 45°.

[0081] In some examples of the present application, with reference to Figures 12 and 13, the grid structure includes a plurality of grid ridges 201, the plurality of grid ridges 201 arranged in a second direction with a second periodic interval P2, and in a third direction with a third periodic interval P3, and between any two adjacent grid ridges 201 there are grid grooves 202, and at least a portion of the grid grooves 202 is an air groove 203. The average value of the refractive index of different materials within the periodicity of the lattice unit of the aforementioned lattice structure. JPEG2026070473000080.jpg75 is as follows: JPEG2026070473000081.jpg1639, JPEG2026070473000082.jpg11134, V1 is the volume of the lattice ridge 201, n1 is the refractive index of the lattice ridge 201, V2 is the volume of the air groove 203, n2 is the refractive index of air, V3 is the volume of the first type of filling material filled in the lattice groove 202, n3 is the refractive index of the first type of filling material filled in the lattice groove 202, V m n is the volume of the m-th type of filling material to be filled into the grid groove 202, and n m V is the refractive index of the m-th type filling material that is filled into the lattice groove 202. unitcell =(P2*P3)*H, where H is the height of the lattice ridge 201.

[0082] The present invention relates to a two-dimensional lattice structure in which the average refractive index of different materials within the lattice unit period of the lattice structure is precisely controlled by controlling the material composition and volume within the lattice ridges 201 and lattice grooves 202. Achieves a rational design for JPEG2026070473000083.jpg75.

[0083] The grid grooves 202 are located between adjacent grid ridges 201, and at least a portion of the grid grooves 202 is an air groove 203. Of course, one or more different materials can be filled into the grid grooves 202.

[0084] By precisely adjusting the material composition and volume within the lattice ridges 201 and lattice grooves 202, the average refractive index of different materials within the lattice unit period of the lattice structure can be adjusted. The JPEG2026070473000084.jpg75 can be controlled, thereby enabling control over the movement of the diffraction efficiency curve. This helps to improve the output coupling efficiency of light rays at specific angles, which is crucial for improving the overall optical efficiency of diffractive optical structures, especially in augmented reality (AR) optical schemes.

[0085] The two-dimensional lattice structure in this example achieves fine control of the average refractive index of the lattice structure by precisely controlling the material composition and volume distribution, thereby further improving diffraction efficiency and the overall optical performance of the diffractive optical structure.

[0086] In some examples of the present application, referring to Figures 8 to 10, the lattice structure further comprises at least one layer of filler material, wherein the refractive index of the filler material and the lattice ridge 201 are different.

[0087] Referring to Figures 8 to 10, the lattice structure may further include at least one layer of filler material with a refractive index different from that of the lattice ridge 201 (the filler material may form a filler layer covering the lattice structure). Such a design introduces additional degrees of freedom for adjusting the refractive index.

[0088] The introduction of the filler material may employ multiple manufacturing processes, such as ALD deposition, PVD deposition, and CVD deposition. These processes allow for precise control of the thickness of the formed filler material, thereby ensuring that the optical properties of the lattice structure reach the expected level.

[0089] In some examples of the present application, referring to Figure 8, the at least one layer of filler material includes a first type of filler material 204 covering the surface of the grid ridge 201 and the groove walls and bottom of the grid groove 202, wherein the grid groove 202 includes air grooves 203 and the first type of filler material 204.

[0090] In the present example, the lattice structure further includes a first type of filler material 204 that covers the surface of the lattice ridge 201 and the groove walls and bottom of the lattice groove 202, and still retains some space as air grooves 203 within the lattice groove 202. Here, the first type of filler material 204 may be a low refractive index material, and the introduction of the first type of filler material 204 is the average value of the refractive indices of different materials within the lattice unit period of the lattice structure. JPEG2026070473000085.jpg75 provides more control means. By selecting the refractive index of an appropriate first type of filler material, the average value of the refractive index of different materials within the lattice unit period of the lattice structure is obtained. JPEG2026070473000086.jpg75 can be precisely adjusted, and further influences the output coupling efficiency curve of the grid structure. By retaining the air groove 203, structural stability can be ensured, while at the same time, the refractive index of the grid groove 202 portion can be further reduced.

[0091] In some examples of the present application, referring to Figure 9, the at least one layer of filler material includes a second type of filler material 205 placed on the first type of filler material 204, and the lattice groove 202 contains the second type of filler material 205 and simultaneously holds an air groove 203, wherein the refractive indices of the first type of filler material 204 and the second type of filler material 205 are different.

[0092] Referring to Figure 9, this example further increases the amount of the second type of filler material 205 based on the first type of filler material 204, while simultaneously maintaining some space as air grooves 203 within the lattice grooves 202. Here, the refractive indices of the first type of filler material 204 and the second type of filler material 205 are different. By further increasing the amount of the second type of filler material 205, which has a refractive index different from that of the first type of filler material 204, the average value of the refractive indices of the different materials within the lattice unit period of the lattice structure is obtained. The control range of JPEG2026070473000087.jpg75 can be further expanded. This helps to precisely control the output coupling efficiency within a wider angular range. Designs incorporating multilayer filler materials allow for finer control of the peak value position and shape of the efficiency curve, thereby meeting the specific requirements under different application scenarios.

[0093] In some examples of the present application, referring to Figure 10, the at least one layer of filler further comprises a third type of filler 206 covering the surface of the second type of filler 205 away from the first type of filler 204, and the inside of the grid groove 202 further comprises the third type of filler 206 filling the air groove 203, wherein the refractive indices of the first type of filler 204, the second type of filler 205, and the third type of filler 206 are each different.

[0094] In this example, referring to Figure 10, the lattice structure further includes a first type of filler material 204, a second type of filler material 205, and a third type of filler material 206, with each of the three layers having a different refractive index. The combination of the three layers of filler materials with different refractive indices results in the average value of the refractive indices of the different materials within the lattice unit period of the lattice structure. The control of JPEG2026070473000088.jpg75 reaches a higher precision. This provides strong support for achieving precise control of the lattice diffraction efficiency curve.

[0095] Furthermore, filler materials with different refractive indices can result in different optical properties, such as different light transmittances and scattering characteristics. The combination of these properties allows the lattice structure to exhibit diverse optical performance under different conditions.

[0096] To summarize, referring to Figures 8 to 10, these three examples introduce different numbers of filling materials with different refractive indices and maintain design means such as air grooves 203, thereby reducing the average refractive index of different materials within the lattice unit period of the lattice structure of the output coupling region 2. This design achieves precise control and a significant improvement in optical performance of JPEG2026070473000089.jpg75. These designs not only help improve the overall optical efficiency of diffractive optical structures, but also provide reliable and flexible technical support for applications in fields such as augmented reality.

[0097] Another embodiment of the present application provides a myopia display device. The myopia display device includes an image source and the diffractive optical structure, wherein a ray emitted from the image source can be incident on an input coupling region 1 on the diffractive optical structure.

[0098] Here, the image source is, for example, a projector.

[0099] Here, the diffractive optical structure is, for example, a diffractive optical waveguide.

[0100] The myopia display device according to the embodiment of this application is, for example, an AR optical display device. Furthermore, the AR optical display device is, for example, AR smart glasses or an AR smart helmet.

[0101] Specific embodiments of the myopia indicator device of the present invention may refer to each embodiment of the diffractive optical structure described above, and since they have at least all the beneficial effects brought about by the technical solutions of the above embodiments, they will not be described further here.

[0102] The above examples have focused on explaining the differences between each example. While the different optimization features between each example can be combined to form a superior example, as long as they are not contradictory, this will not be repeated here for the sake of brevity.

[0103] While several specific embodiments of the present application have been described in detail by example, those skilled in the art should understand that the above embodiments are for illustrative purposes only and do not limit the scope of the present application. Those skilled in the art should also understand that the above embodiments can be modified without departing from the scope and spirit of the present application. The scope of the present application is limited by the appended claims. [Explanation of Symbols]

[0104] 1. Input coupling region, 2. Output coupling region, 3. Substrate, 201. Grid ridge, 202. Grid groove, 203. Air groove, 204. Type 1 filler material, 205. Type 2 filler material, 206. Type 3 filler material.

Claims

1. A diffractive optical structure comprising a substrate (3), and an input coupling region (1) and an output coupling region (2) installed on the substrate (3), The output coupling region (2) includes a lattice structure comprising a plurality of periodically arranged lattice ridges (201) and lattice grooves (202) between adjacent lattice ridges (201), wherein the lattice grooves (202) are filled with materials of at least two different refractive indices. The average value of the refractive indices of different materials within the lattice unit period of the aforementioned lattice structure is: and 、 、 V １ ~V ｍ These are the volumes or areas of materials from type 1 to type m, respectively. n １ ~n ｍ These are the refractive indices of materials from type 1 to type m, respectively. V ｕｎｉｔｃｅｌｌ A diffractive optical structure characterized in that is the volume or area of ​​the unit period of the lattice.

2. The average value of the refractive index of different materials within the periodicity of the lattice unit of the aforementioned lattice structure. teeth, The diffractive optical structure according to claim 1, characterized in that it is the same.

3. The substrate (3) includes two opposing surfaces, and the input coupling region (1) and the output coupling region (2) are located on at least one surface of the substrate (3). The input coupling region (1) is used to input coupling an external light ray into the interior of the substrate (3). The diffractive optical structure according to claim 1, characterized in that the output coupling region (2) is used to dilate the pupil and coupled the light ray to the output.

4. The aforementioned lattice structure has a first period P along the first direction. １ It includes a plurality of grid ridges (201) arranged according to the grid grooves (202) between any two adjacent grid ridges (201), where at least a portion of the grid grooves (202) is an air groove (203), The average value of the refractive index of different materials within the periodicity of the lattice unit of the aforementioned lattice structure. The following applies: 、 Here, , V １ is the area of the cross-section of the grating ridge (201), and n １ is the refractive index of the grating ridge (201), and V ２ is the area of the cross-section of the air groove (203), and n ２ is the refractive index of air, and V ３ is the area of the cross-section of the first type of filling material filled in the grating groove (202), and n ３ is the refractive index of the first type of filling material filled in the grating groove (202), and V ｍ is the area of the cross-section of the m-th type of filling material filled in the grating groove (202), and n ｍ is the refractive index of the m-th type of filling material filled in the grating groove (202), and V ｕｎｉｔｃｅｌｌ = P １ * H, where H is the height of the grating ridge (201), The diffractive optical structure according to any one of claims 1 to 3, characterized in that.

5. The aforementioned lattice structure includes a plurality of lattice ridges (201), The plurality of lattice ridges (201) have a second period P along the second direction. ２ Arranged at intervals, with a third period P along a third direction ３ Arranged at intervals, Between any two adjacent grid ridges (201) there is a grid groove (202), At least a portion of the aforementioned grid groove (202) is an air groove (203), The average value of the refractive index of different materials within the periodicity of the lattice unit of the aforementioned lattice structure. The following applies: 、 , V １ n is the volume of the lattice ridge (201), and n １ V is the refractive index of the lattice ridge (201), and ２ n is the volume of the air groove (203), ２ V is the refractive index of air. ３ n is the volume of the first type of filling material to be filled into the grid groove (202), ３ V is the refractive index of the first type of filling material that is filled into the lattice groove (202), ｍ n is the volume of the m-th type of filling material to be filled into the grid groove (202), and n ｍ V is the refractive index of the m-th type filling material that is filled into the lattice groove (202), ｕｎｉｔｃｅｌｌ = (P ２ *P ３ ) *H,H is the height of the lattice ridge (201), characterized in that the diffractive optical structure is as described in any one of claims 1 to 3.

6. The diffractive optical structure according to any one of claims 1 to 3, characterized in that the lattice structure is covered with at least one layer of filler material, and the refractive index of the filler material is different from that of the lattice ridge (201).

7. The diffractive optical structure according to claim 6, wherein the at least one layer of filling material includes a first type of filling material (204) that covers the surface of the lattice ridge (201) and the groove walls and bottom of the lattice groove (202), wherein the lattice groove (202) includes an air groove (203) and the first type of filling material (204).

8. The diffractive optical structure according to claim 7, wherein the at least one layer of filler material further comprises a second type of filler material (205) that covers the first type of filler material (204), and the lattice groove (202) further comprises the second type of filler material (205) and simultaneously holds air grooves (203) where the refractive indices of the first type of filler material (204) and the second type of filler material (205) are different.

9. The at least one layer of filling material further comprises a third type of filling material (206) covering the surface of the second type of filling material (205) away from the first type of filling material (204), and the inside of the grid groove (202) further comprises the third type of filling material (206) filling the air groove (203), The diffractive optical structure according to claim 8, characterized in that the refractive indices of the first type of filler material (204), the second type of filler material (205), and the third type of filler material (206) are all different.

10. Myopia display device, Image source and, Myopia display device comprising a diffractive optical structure according to any one of claims 1 to 3, wherein a light ray emitted from the image source can be incident on the input coupling region (1) on the diffractive optical structure.

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