WO2025060258A1

WO2025060258A1 - Diffractive optical waveguide and display module

Info

Publication number: WO2025060258A1
Application number: PCT/CN2023/136332
Authority: WO
Inventors: 罗明辉; 杨明; 李瑞彬; 周振; 赵改娜; 李玲; 乔文; 陈林森
Original assignee: Suzhou University; SVG Tech Group Co Ltd
Current assignee: Suzhou University; SVG Tech Group Co Ltd
Priority date: 2023-09-18
Filing date: 2023-12-05
Publication date: 2025-03-27
Anticipated expiration: 2026-03-18
Also published as: CN119644495A

Abstract

The present invention relates to a diffractive optical waveguide and a display module. The diffractive optical waveguide comprises a waveguide substrate, the waveguide substrate comprising an in-coupling region and an out-coupling region. The direction from the in-coupling region to the out-coupling region is a first direction. The out-coupling region comprises a first sub-out-coupling region and a second sub-out-coupling region. The first sub-out-coupling region comprises at least two first out-coupling blocks which are sequentially arranged in the first direction, and efficiency modulation functions of the at least two first out-coupling blocks present a progressive trend in the first direction. In a direction perpendicular to the first direction, the second sub-out-coupling region comprises at least two second out-coupling blocks which are sequentially arranged in a direction away from the first sub-out-coupling region, and efficiency modulation functions of the at least two second out-coupling blocks present a progressive trend in the direction away from the first sub-out-coupling region. In the diffractive optical waveguide of the present invention, efficiency partitioning can be separately performed on the first sub-out-coupling region and the second sub-out-coupling region, thereby improving the uniformity of brightness among different observation images in the range of an eyebox.

Description

Diffractive optical waveguide and display module

Technical Field

本发明涉及显示技术领域，特别是涉及一种衍射光波导及显示模组。The present invention relates to the field of display technology, and in particular to a diffraction optical waveguide and a display module.

Background Art

[根据细则26改正 13.12.2023]
增强现实(AR)显示是观察者在观看外界真实物体的同时，叠加在真实环境中的图像或者数据等信息也可被观看，因此被广泛应用于各个领域，尤其在军事领域及消费领域。从2012年谷歌公司发布风靡全球的Google glass，到2014年Facebook以二十亿美元收购的Oculus，再到2016年访美期间试戴了微软的Hololens、谷歌领投的Magic Leap、及微软发布的Hololens2、OPPO发布的AR眼镜，以及最近火热的AR-HUD，无一例外地向世人展示增强现实显示的巨大的应用前景。究其原因，增强现实显示提供了传统显示设备不具备的与真实环境无障碍的实时实地交互的功能，给用户带来了全新的视觉体验。但因此增强现实显示中首要的问题就是如何减少显示设备的体积和重量，并提供足够的亮度、视场角，实现设备轻便化和高空间分辨率、高角分辨率的增虚实融合呈现效果。[Corrected 13.12.2023 in accordance with Rule 26]
Augmented reality (AR) display is a display in which the observer can watch the images or data superimposed on the real environment while watching the real objects in the outside world. Therefore, it is widely used in various fields, especially in the military and consumer fields. From the release of Google Glass, which swept the world in 2012, to Facebook's acquisition of Oculus for $2 billion in 2014, to the trial wearing of Microsoft's Hololens during the visit to the United States in 2016, Magic Leap led by Google, Hololens2 released by Microsoft, AR glasses released by OPPO, and the recently popular AR-HUD, all of them showed the world the huge application prospects of augmented reality display. The reason is that augmented reality display provides the function of barrier-free real-time interaction with the real environment that traditional display devices do not have, bringing users a new visual experience. However, the primary problem in augmented reality display is how to reduce the size and weight of the display device, and provide sufficient brightness and field of view, so as to achieve lightweight equipment and high spatial resolution and high angular resolution of augmented reality fusion presentation effect.

增强现实显示光学技术发展至今，主要方案大致分为共轴侧视棱镜方案、阵列式半透膜波导方案、自由曲面方案、衍射光波导方案等，不同方案所具备的显示性能不同。当前车载抬头显示主要采用自由曲面的设计，其模组体积巨大；近眼显示领域众多巨头包括微软、Meta、Apple、Google、Snap等均采用较为主流的衍射光波导技术方案，衍射光波导是利用光栅的衍射特性来设计“光路”，让光在设计好的路径上传播，将微投影系统发出的光导入人眼。而此类方案主要的优势是体积小、轻薄，而基于衍射光波导的增强现实显示模组延续了超小的体积优势，更有助于穿戴式显示集成与汽车抬头显示的前装。Since the development of augmented reality display optical technology, the main solutions are roughly divided into coaxial side-view prism solution, array semi-transparent film waveguide solution, free-form surface solution, diffraction optical waveguide solution, etc. Different solutions have different display performance. The current in-vehicle head-up display mainly adopts the design of free-form surface, and its module volume is huge; many giants in the field of near-eye display, including Microsoft, Meta, Apple, Google, Snap, etc., all adopt the more mainstream diffraction optical waveguide technology solution. The diffraction optical waveguide uses the diffraction characteristics of the grating to design the "optical path", allowing light to propagate on the designed path and guide the light emitted by the micro-projection system into the human eye. The main advantage of this type of solution is small size and thinness, and the augmented reality display module based on diffraction optical waveguide continues the advantage of ultra-small size, which is more conducive to the integration of wearable displays and the front installation of automotive head-up displays.

传统的衍射光波导的方案，采用耦入-转折-耦出的光传导设计，通过衍射扩瞳的理论方法，实现大眼盒显示。如图1所示，传统的一种衍射光波导100’包括波导基底110’，波导基底110’包括耦入区域120’和耦出区域130’。其中，衍射光波导100’的整个耦出区域130’为一种参数相同的光栅结构，当入射光线沿图1中箭头方向从耦入区域120’耦合进入波导基底110’，并在波导基底110’内传导时，第一次经过耦出区域130’，并被耦出区域120’的光栅结构衍射出射的光能最强，继此之后，每一次的出射光的能量逐步减弱。这是因为耦出区域130’仅为一种光栅结构，具备相同的衍射效率，而每经过一次衍射之后，可以继续传导的总能量必然衰减，而相同的衍射效率必然会导致下次的出射能量降低，这会导致人眼在透过波导移动观察时，眼盒范围内的能量不均匀带来的明显图像亮暗。因此，传统的衍射光波导在针对耦出区域的部分，由于衍射效率的控制不均，常常会导致眼盒范围内不同观察图像亮度不均匀的问题。The traditional diffraction optical waveguide solution adopts a coupling-turning-coupling light transmission design, and realizes a large eye box display through the theoretical method of diffraction pupil expansion. As shown in FIG1 , a traditional diffraction optical waveguide 100 ′ includes a waveguide substrate 110 ′, and the waveguide substrate 110 ′ includes a coupling-in region 120 ′ and a coupling-out region 130 ′. Among them, the entire coupling-out region 130 ′ of the diffraction optical waveguide 100 ′ is a grating structure with the same parameters. When the incident light is coupled from the coupling-in region 120 ′ into the waveguide substrate 110 ′ along the direction of the arrow in FIG1 , and is transmitted in the waveguide substrate 110 ′, the light energy that passes through the coupling-out region 130 ′ for the first time and is diffracted by the grating structure of the coupling-out region 120 ′ is the strongest. After that, the energy of each outgoing light gradually weakens. This is because the out-coupling region 130' is only a grating structure with the same diffraction efficiency. After each diffraction, the total energy that can continue to be transmitted will inevitably decay, and the same diffraction efficiency will inevitably lead to a decrease in the next outgoing energy, which will cause the energy unevenness within the eye box range to cause obvious image brightness when the human eye moves through the waveguide. Therefore, in the part of the out-coupling region, the uneven control of the diffraction efficiency of the traditional diffraction optical waveguide often leads to the problem of uneven brightness of different observation images within the eye box range.

发明内容Summary of the invention

基于此，有必要针对如何提升眼盒范围内不同观察图像亮度均匀性的问题，提供一种衍射光波导及显示模组。Based on this, it is necessary to provide a diffraction light waveguide and a display module to solve the problem of how to improve the brightness uniformity of different observation images within the eye box.

一种衍射光波导，所述衍射光波导包括波导基底，所述波导基底包括耦入区域和位于所述耦入区域一侧的耦出区域，所述耦入区域用于将图像光线耦入至所述波导基底内，所述耦出区域用于将在所述波导基底内传导的图像光线耦出；A diffractive optical waveguide, comprising a waveguide substrate, the waveguide substrate comprising an incoupling region and an outcoupling region located on one side of the incoupling region, the incoupling region being used to couple image light into the waveguide substrate, and the outcoupling region being used to couple out the image light conducted in the waveguide substrate;

自所述耦入区域向所述耦出区域的方向为第一方向，所述耦出区域包括第一子耦出区域和第二子耦出区域，所述第一子耦出区域靠近所述耦入区域设置，所述第二子耦出区域沿垂直于所述第一方向远离所述耦入区域设置；The direction from the coupling-in region to the coupling-out region is a first direction, the coupling-out region includes a first sub-coupling region and a second sub-coupling region, the first sub-coupling region is arranged close to the coupling-in region, and the second sub-coupling region is arranged away from the coupling-in region along a direction perpendicular to the first direction;

所述第一子耦出区域包括沿所述第一方向依次设置的至少两个第一耦出块，且至少两个所述第一耦出块的效率调制功能沿所述第一方向呈递进趋势；The first sub-coupling region includes at least two first coupling blocks arranged in sequence along the first direction, and the efficiency modulation functions of the at least two first coupling blocks are in a progressive trend along the first direction;

在垂直于所述第一方向的方向上，所述第二子耦出区域包括沿远离所述第一子耦出区域的方向依次设置的至少两个第二耦出块，且至少两个所述第二耦出块的效率调制功能沿远离所述第一子耦出区域的方向呈递进趋势。In a direction perpendicular to the first direction, the second sub-coupling region includes at least two second outcoupling blocks arranged in sequence along a direction away from the first sub-coupling region, and the efficiency modulation functions of the at least two second outcoupling blocks show a progressive trend along the direction away from the first sub-coupling region.

应用本发明技术方案的衍射光波导，能够通过分别对第一子耦出区域和第二子耦出区域进行效率分区，从而合理分配单位面积的衍射能量，均衡耦出区域内不同位置的衍射效率，从而提升眼盒范围内不同观察图像亮度均匀性，有利于广泛应用。The diffraction optical waveguide using the technical solution of the present invention can reasonably distribute the diffraction energy per unit area by performing efficiency partitioning on the first sub-coupling area and the second sub-coupling area respectively, and balance the diffraction efficiency at different positions in the coupling area, thereby improving the brightness uniformity of different observation images within the eye box range, which is conducive to wide application.

在一个可行的实现方式中，所述第二子耦出区域的个数为两个，且两个所述第二子耦出区域关于所述第一子耦出区域对称分布。In a feasible implementation manner, the number of the second sub-coupling regions is two, and the two second sub-coupling regions are symmetrically distributed with respect to the first sub-coupling region.

在一个可行的实现方式中，所述第一耦出块沿垂直于所述第一方向的宽度不小于进入所述耦入区域的光斑宽度，所述第一耦出块沿所述第一方向的长度基于图像光线在所述第一耦出块内的预设截止效率阈值得到。In a feasible implementation, the width of the first outcoupling block along the first direction perpendicular to the first direction is not less than the width of the light spot entering the coupling-in region, and the length of the first outcoupling block along the first direction is obtained based on a preset cutoff efficiency threshold of the image light in the first outcoupling block.

在一个可行的实现方式中，至少两个所述第一耦出块沿所述第一方向的长度递减。In a feasible implementation, the lengths of at least two of the first outcoupling blocks along the first direction decrease gradually.

在一个可行的实现方式中，所述第一耦出块沿所述第一方向的长度为n*d，n为全反射次数，并基于以下步骤得到：In a feasible implementation, the length of the first outcoupling block along the first direction is n*d, where n is the number of total reflections, and is obtained based on the following steps:

所述第一耦出块内设有若干光栅结构，定义初始光栅结构沿垂直于所述第一方向上向相邻所述光栅结构的传导效率为a，定义初始光栅结构沿所述第一方向上向相邻所述光栅结构的传导效率b；以及A plurality of grating structures are provided in the first outcoupling block, a transmission efficiency of an initial grating structure to an adjacent grating structure along a direction perpendicular to the first direction is defined as a, and a transmission efficiency of an initial grating structure to an adjacent grating structure along the first direction is defined as b; and

图像光线在所述第一耦出块内的第n次全反射沿垂直于所述第一方向上的传导效率为a*b^n-1，图像光线在所述第一耦出块内的第n次全反射沿所述第一方向的传导效率为bⁿ，预设图像光线在所述第一耦出块内的截止效率阈值为ε，当第n次传导的效率a*b^n-1＜a*ε时结束所述第一耦出块，此时所述第一耦出块沿所述第一方向的长度为n*d；The transmission efficiency of the image light in the first outcoupling block in the direction perpendicular to the first direction after the n-th total reflection is a* ^bn-1 , the transmission efficiency of the image light in the first outcoupling block in the direction perpendicular to the first direction after the n-th total reflection is ^bn , the cutoff efficiency threshold of the image light in the first outcoupling block is preset to be ε, and the first outcoupling block is terminated when the efficiency of the n-th transmission is a* ^bn-1 <a*ε, and at this time, the length of the first outcoupling block in the first direction is n*d;

其中d为全反射点间距，并基于公式(I)计算得到：Where d is the total reflection point spacing, and is calculated based on formula (I):

d＝t*tan(arcsin(λ/p/n₀))*2(I)；d=t*tan(arcsin(λ/p/n ₀ ))*2(I);

公式(I)中，t为波导基底的厚度，λ为入射波长，p为光栅周期，n₀为波导折射率。In formula (I), t is the thickness of the waveguide substrate, λ is the incident wavelength, p is the grating period, and _n0 is the waveguide refractive index.

在一个可行的实现方式中，所述第二耦出块沿垂直于所述第一方向的宽度基于图像光线在所述第二耦出块内的预设截止效率阈值得到，所述第二耦出块沿所述第一方向的长度等于所述第一子耦出区域沿所述第一方向的长度。In a feasible implementation, the width of the second outcoupling block along the direction perpendicular to the first direction is obtained based on a preset cutoff efficiency threshold of the image light in the second outcoupling block, and the length of the second outcoupling block along the first direction is equal to the length of the first sub-outcoupling region along the first direction.

在一个可行的实现方式中，在垂直于所述第一方向的方向上，至少两个所述第二耦出块沿远离所述第一子耦出区域方向的宽度递减。In a feasible implementation, in a direction perpendicular to the first direction, the widths of at least two of the second outcoupling blocks decrease gradually in a direction away from the first sub-outcoupling region.

在一个可行的实现方式中，所述第二耦出块沿垂直于所述第一方向的宽度为n*d，n为全反射次数，并基于以下步骤得到：In a feasible implementation, the width of the second outcoupling block along the direction perpendicular to the first direction is n*d, where n is the number of total reflections, and is obtained based on the following steps:

所述第二耦出块内设有若干光栅结构，定义初始光栅结构沿垂直于所述第一方向上向相邻所述光栅结构的传导效率为a，定义初始光栅结构沿所述第一方向上向相邻所述光栅结构的传导效率c；以及A plurality of grating structures are provided in the second outcoupling block, a transmission efficiency of an initial grating structure to an adjacent grating structure along a direction perpendicular to the first direction is defined as a, and a transmission efficiency of an initial grating structure to an adjacent grating structure along the first direction is defined as c; and

图像光线在所述第二耦出块内的第n次全反射沿垂直于所述第一方向上的传导效率为a*c^n-1，图像光线在所述第二耦出块内的第n次全反射沿所述第一方向的传导效率为cⁿ，预设图像光线在所述第二耦出块内的截止效率阈值为ε，当第n次传导的效率a*b^n-1＜a*ε时结束所述第二耦出块，此时所述第二耦出块沿垂直于所述第一方向的宽度为n*d；The transmission efficiency of the image light in the second outcoupling block in the direction perpendicular to the first direction during the n-th total reflection is a*c ^n-1 , the transmission efficiency of the image light in the second outcoupling block in the direction perpendicular to the first direction during the n-th total reflection is c ⁿ , the cutoff efficiency threshold of the image light in the second outcoupling block is preset to be ε, and the second outcoupling block is terminated when the efficiency of the n-th transmission is a*b ^n-1 ＜a*ε, and at this time, the width of the second outcoupling block in the direction perpendicular to the first direction is n*d;

其中d为全反射点间距，并基于公式(II)计算得到：d＝t*tan(arcsin(λ/p/n₀))*2*sin(60°) (II)；Wherein d is the total reflection point spacing, and is calculated based on formula (II): d = t*tan(arcsin(λ/p/n ₀ ))*2*sin(60°) (II);

公式(II)中，t为波导基底的厚度，λ为入射波长，p为光栅周期，n₀为波导折射率。In formula (II), t is the thickness of the waveguide substrate, λ is the incident wavelength, p is the grating period, and _n0 is the waveguide refractive index.

一种显示模组，包括上述任一的衍射光波导。A display module comprises any of the above diffraction light waveguides.

本发明技术方案的显示模组包括上述任一的衍射光波导，能够通过分别对第一子耦出区域和第二子耦出区域进行效率分区，从而合理分配单位面积的衍射能量，均衡耦出区域内不同位置的衍射效率，从而提升眼盒范围内不同观察图像亮度均匀性，有利于广泛应用。The display module of the technical solution of the present invention includes any of the above-mentioned diffraction optical waveguides, and can reasonably distribute the diffraction energy per unit area by performing efficiency partitioning on the first sub-coupling area and the second sub-coupling area respectively, and balance the diffraction efficiency at different positions in the coupling area, thereby improving the brightness uniformity of different observation images within the eye box range, which is conducive to wide application.

在一个可行的实现方式中，所述显示模组为抬头显示模组或者增强现实可穿戴显示模组。In a feasible implementation, the display module is a head-up display module or an augmented reality wearable display module.

BRIEF DESCRIPTION OF THE DRAWINGS

图1为传统的一种衍射光波导的光线传导示意图；FIG1 is a schematic diagram of light transmission of a conventional diffraction optical waveguide;

图2为本发明一实施方式的衍射光波导的结构示意图；FIG2 is a schematic structural diagram of a diffractive optical waveguide according to an embodiment of the present invention;

图3为本发明一实施方式的衍射光波导中第一耦出块的限定原理图；FIG3 is a diagram showing the definition principle of the first outcoupling block in the diffractive optical waveguide according to an embodiment of the present invention;

图4为本发明一实施方式的衍射光波导中第二耦出块的限定原理图；FIG4 is a diagram showing the definition principle of the second outcoupling block in the diffractive optical waveguide according to an embodiment of the present invention;

图5为本发明第一实施方式的衍射光波导的制备示意图；FIG5 is a schematic diagram of preparing a diffractive optical waveguide according to the first embodiment of the present invention;

图6为本发明第二实施方式的衍射光波导的制备示意图；FIG6 is a schematic diagram of preparing a diffractive optical waveguide according to a second embodiment of the present invention;

图7为本发明第三实施方式的衍射光波导的制备示意图；FIG7 is a schematic diagram of manufacturing a diffractive optical waveguide according to a third embodiment of the present invention;

图8为本发明第三实施方式的衍射光波导的制备过程中光阑式曝光的设计示意图；8 is a schematic diagram of the design of aperture exposure in the process of preparing a diffractive optical waveguide according to the third embodiment of the present invention;

图9为本发明一实施方式的抬头显示模组的示意图；FIG9 is a schematic diagram of a head-up display module according to an embodiment of the present invention;

图10为本发明一实施方式的增强现实可穿戴显示模组的示意图；FIG10 is a schematic diagram of an augmented reality wearable display module according to an embodiment of the present invention;

图11为本发明实施例1的衍射光波导的结构示意图；FIG11 is a schematic structural diagram of a diffractive optical waveguide according to Embodiment 1 of the present invention;

图12为本发明实施例1的衍射光波导的耦出区域光线出射仿真图；FIG12 is a simulation diagram of light emission from the outcoupling region of the diffraction optical waveguide according to Example 1 of the present invention;

图13为本发明实施例2的衍射光波导的结构示意图；FIG13 is a schematic structural diagram of a diffractive optical waveguide according to Embodiment 2 of the present invention;

图14为本发明实施例2的衍射光波导0度入射时的耦出区域光线出射仿真图；FIG14 is a simulation diagram of light emission from the outcoupling region of the diffraction light waveguide of Example 2 of the present invention at 0 degree incidence;

图15为本发明实施例2的衍射光波导-5度入射时的耦出区域光线出射仿真图；FIG15 is a simulation diagram of light emission from the outcoupling region of the diffraction light waveguide of Example 2 of the present invention at -5 degrees of incidence;

图16为本发明实施例2的衍射光波导5度入射时的耦出区域光线出射仿真图；FIG16 is a simulation diagram of light emission from the outcoupling region of the diffractive optical waveguide of Example 2 of the present invention at 5 degrees of incidence;

图17为对比例1的衍射光波导的结构示意图；FIG17 is a schematic structural diagram of a diffraction optical waveguide of Comparative Example 1;

图18为对比例1的衍射光波导的耦出区域光线出射仿真图；FIG18 is a simulation diagram of light emission in the outcoupling region of the diffraction optical waveguide of Comparative Example 1;

图19为对比例2的衍射光波导的结构示意图；FIG19 is a schematic structural diagram of a diffraction optical waveguide of Comparative Example 2;

图20为对比例2的衍射光波导的耦出区域光线出射仿真图。FIG20 is a simulation diagram of light emission from the outcoupling area of the diffraction optical waveguide of comparative example 2.

DETAILED DESCRIPTION

为使本发明的上述目的、特征和优点能够更加明显易懂，下面结合附图对本发明的具体实施方式做详细的说明。在下面的描述中阐述了很多具体细节以便于充分理解本发明。但是本发明能够以很多不同于在此描述的其它方式来实施，本领域技术人员可以在不违背本发明内涵的情况下做类似改进，因此本发明不受下面公开的具体实施例的限制。In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

需要说明的是，当元件被称为“固定于”另一个元件，它可以直接在另一个元件上或者也可以存在居中的元件。当一个元件被认为是“连接”另一个元件，它可以是直接连接到另一个元件或者可能同时存在居中元件。本文所使用的术语“垂直的”、“水平的”、“左”、“右”以及类似的表述只是为了说明的目的。It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

除非另有定义，本文所使用的所有的技术和科学术语与属于本发明的技术领域的技术人员通常理解的含义相同。本文中在本发明的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本发明。本文所使用的术语“及/或”包括一个或多个相关的所列项目的任意的和所有的组合。Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and/or" used herein includes any and all combinations of one or more related listed items.

请参见图2，本发明一实施方式的衍射光波导100包括波导基底110，波导基底110包括耦入区域120和位于耦入区域120一侧的耦出区域130，耦入区域120用于将图像光线耦入至波导基底110内，耦出区域130用于将在波导基底110内传导的图像光线耦出，具体出射和传导功能。Please refer to FIG. 2 . A diffraction optical waveguide 100 according to an embodiment of the present invention includes a waveguide substrate 110. The waveguide substrate 110 includes a coupling-in region 120 and a coupling-out region 130 located on one side of the coupling-in region 120. The coupling-in region 120 is used to couple image light into the waveguide substrate 110, and the coupling-out region 130 is used to couple out image light conducted in the waveguide substrate 110, specifically performing emission and conduction functions.

其中，波导基底110可以是玻璃或者树脂，具备较高的可见光透过特性。耦入区域120的口径不小于入射光束宽度，入射光束宽度受限于波导基底110的材料折射率、厚度以及入射角度等参数。The waveguide substrate 110 may be glass or resin, and has a high visible light transmission characteristic. The aperture of the coupling region 120 is not less than the incident beam width, and the incident beam width is limited by parameters such as the material refractive index, thickness and incident angle of the waveguide substrate 110 .

其中，自耦入区域120向耦出区域130的方向为第一方向(即图2中x方向)，耦出区域130包括第一子耦出区域131和第二子耦出区域133，第一子耦出区域131靠近耦入区域120设置，第二子耦出区域133沿垂直于第一方向(即图2中y方向或者y方向的反方向)远离耦入区域120设置。具体的，第一子耦出区域131与耦入区域120相对设置，第二子耦出区域133位于第一子耦出区域131沿垂直于第一方向的一侧，如图2中所示。较优地，第一子耦出区域131靠近耦入区域120的侧边的长度可以稍大于耦入区域120沿y方向的宽度，以确保图像光线经耦入区域120传导后能够保持在第一子耦出区域131内。The direction from the coupling-in region 120 to the coupling-out region 130 is a first direction (i.e., the x direction in FIG. 2 ), and the coupling-out region 130 includes a first sub-coupling region 131 and a second sub-coupling region 133. The first sub-coupling region 131 is arranged close to the coupling-in region 120, and the second sub-coupling region 133 is arranged away from the coupling-in region 120 along a direction perpendicular to the first direction (i.e., the y direction in FIG. 2 or the opposite direction of the y direction). Specifically, the first sub-coupling region 131 is arranged opposite to the coupling-in region 120, and the second sub-coupling region 133 is located on one side of the first sub-coupling region 131 along a direction perpendicular to the first direction, as shown in FIG. 2 . Preferably, the length of the side of the first sub-coupling region 131 close to the coupling-in region 120 can be slightly greater than the width of the coupling-in region 120 along the y direction, so as to ensure that the image light can remain in the first sub-coupling region 131 after being transmitted through the coupling-in region 120.

其中，第一子耦出区域131包括沿第一方向依次设置的至少两个第一耦出块132，且至少两个第一耦出块132的效率调制功能沿第一方向呈递进趋势。其中，第一耦出块132的效率调制功能指的是第一耦出块132具备的调制光线衍射效率的功能，至少两个第一耦出块132的效率调制功能沿第一方向呈递进趋势指的是，至少两个第一耦出块132具备的调制光线衍射效率的功能越来越强。The first sub-coupling area 131 includes at least two first coupling blocks 132 arranged in sequence along the first direction, and the efficiency modulation function of the at least two first coupling blocks 132 is progressive along the first direction. The efficiency modulation function of the first coupling block 132 refers to the function of modulating the diffraction efficiency of light possessed by the first coupling block 132, and the efficiency modulation function of the at least two first coupling blocks 132 is progressive along the first direction, which means that the function of modulating the diffraction efficiency of light possessed by the at least two first coupling blocks 132 is getting stronger and stronger.

本实施方式中，第一耦出块132的个数为四个，且每个第一耦出块132具备不同的特征结构和光学耦合性能。需要说明的是，本发明的衍射光波导中，第一耦出块132的个数不限于此。In this embodiment, there are four first outcoupling blocks 132, and each first outcoupling block 132 has different characteristic structures and optical coupling performances. It should be noted that in the diffractive optical waveguide of the present invention, the number of first outcoupling blocks 132 is not limited thereto.

其中，在垂直于第一方向的方向上，第二子耦出区域133包括沿远离第一子耦出区域131的方向依次设置的至少两个第二耦出块134，且至少两个第二耦出块134的效率调制功能沿远离第一子耦出区域131的方向呈递进趋势。其中，第二耦出块134的效率调制功能指的是第二耦出块134具备的调制光线衍射效率的功能，至少两个第二耦出块134的效率调制功能沿远离第一子耦出区域131的方向呈递进趋势指的是，至少两个第二耦出块134具备的调制光线衍射效率的功能越来越强。In the direction perpendicular to the first direction, the second outcoupling sub-region 133 includes at least two second outcoupling blocks 134 sequentially arranged in a direction away from the first outcoupling sub-region 131, and the efficiency modulation functions of the at least two second outcoupling blocks 134 are progressively increased in the direction away from the first outcoupling sub-region 131. The efficiency modulation function of the second outcoupling block 134 refers to the function of modulating the diffraction efficiency of light possessed by the second outcoupling block 134, and the efficiency modulation functions of the at least two second outcoupling blocks 134 are progressively increased in the direction away from the first outcoupling sub-region 131, which means that the function of modulating the diffraction efficiency of light possessed by the at least two second outcoupling blocks 134 is increasingly stronger.

本实施方式中，位于第一子耦出区域131一侧的第二子耦出区域133中，第二耦出块134的个数为六个，且每个第二耦出块134具备不同的特征结构和光学耦合性能。需要说明的是，本发明的衍射光波导中，第二耦出块134的个数不限于此。In this embodiment, in the second sub-coupling region 133 located on one side of the first sub-coupling region 131, the number of the second coupling blocks 134 is six, and each second coupling block 134 has a different characteristic structure and optical coupling performance. It should be noted that in the diffractive optical waveguide of the present invention, the number of the second coupling blocks 134 is not limited thereto.

本实施方式的衍射光波导100能够通过分别对第一子耦出区域131和第二子耦出区域133进行效率分区，从而合理分配单位面积的衍射能量，均衡耦出区域130内不同位置的衍射效率，从而提升眼盒范围内不同观察图像亮度均匀性。The diffraction optical waveguide 100 of this embodiment can reasonably distribute the diffraction energy per unit area by performing efficiency partitioning on the first sub-coupling area 131 and the second sub-coupling area 133 respectively, and balance the diffraction efficiency at different positions in the out-coupling area 130, thereby improving the brightness uniformity of different observation images within the eye box range.

在前述实施方式的基础上，第二子耦出区域133的个数为两个，且两个第二子耦出区域133关于第一子耦出区域131对称分布。需要说明的是，两个第二子耦出区域133亦可以不对称分布，具体结构可以根据耦入区域120的位置进行设置。Based on the above-mentioned embodiment, the number of the second sub-coupling regions 133 is two, and the two second sub-coupling regions 133 are symmetrically distributed with respect to the first sub-coupling region 131. It should be noted that the two second sub-coupling regions 133 may also be asymmetrically distributed, and the specific structure may be set according to the position of the coupling region 120.

在前述实施方式的基础上，第一耦出块132沿垂直于第一方向(即图2中y方向或者y方向的反方向)的宽度不小于进入耦入区域120的光斑宽度，第一耦出块132沿第一方向的长度基于图像光线在第一耦出块132内的预设截止效率阈值得到。On the basis of the foregoing implementation, the width of the first outcoupling block 132 along a direction perpendicular to the first direction (i.e., the y direction in FIG. 2 or the opposite direction of the y direction) is not less than the width of the light spot entering the coupling-in region 120, and the length of the first outcoupling block 132 along the first direction is obtained based on a preset cutoff efficiency threshold of the image light in the first outcoupling block 132.

在前述实施方式的基础上，至少两个第一耦出块132沿第一方向的长度递减。当然，本发明的衍射光波导中，至少两个第一耦出块132沿第一方向的长度亦可以相同。Based on the above embodiment, the lengths of at least two first outcoupling blocks 132 along the first direction decrease gradually. Of course, in the diffractive optical waveguide of the present invention, the lengths of at least two first outcoupling blocks 132 along the first direction may also be the same.

在前述实施方式的基础上，请一并参见图3，第一耦出块132沿第一方向(即图3中x方向)的长度为n*d，n为全反射次数，并基于以下步骤得到：Based on the above implementation, please refer to FIG. 3 , the length of the first coupling block 132 along the first direction (ie, the x direction in FIG. 3 ) is n*d, where n is the number of total reflections, and is obtained based on the following steps:

S10、第一耦出块132内设有若干光栅结构，定义初始光栅结构沿垂直于第一方向上向相邻光栅结构的传导效率为a，定义初始光栅结构沿第一方向上向相邻光栅结构的传导效率b；S10, a plurality of grating structures are provided in the first outcoupling block 132, and a transmission efficiency of an initial grating structure to an adjacent grating structure along a direction perpendicular to the first direction is defined as a, and a transmission efficiency of an initial grating structure to an adjacent grating structure along the first direction is defined as b;

S20、图像光线在第一耦出块132内的第n次全反射沿垂直于第一方向上的传导效率为a*b^n-1，图像光线在第一耦出块132内的第n次全反射沿第一方向的传导效率为bⁿ，预设图像光线在第一耦出块132内的截止效率阈值为ε，当第n次传导的效率a*b^n-1＜a*ε时结束第一耦出块132，此时第一耦出块132沿第一方向的长度为n*d。S20, the transmission efficiency of the image light in the first outcoupling block 132 along the direction perpendicular to the first direction after the n-th total reflection is a*bn ^-1 , the transmission efficiency of the image light in the first outcoupling block 132 along the first direction after the n-th total reflection is ^bn , the cutoff efficiency threshold of the image light in the first outcoupling block 132 is preset to ε, and the first outcoupling block 132 is terminated when the efficiency of the n-th transmission a* ^bn-1 ＜a*ε, and at this time, the length of the first outcoupling block 132 along the first direction is n*d.

步骤S20中，d为全反射点间距，并基于公式(I)计算得到：In step S20, d is the total reflection point spacing, which is calculated based on formula (I):

d＝t*tan(arcsin(λ/p/n₀))*2(I)；d=t*tan(arcsin(λ/p/n ₀ ))*2(I);

公式(I)中，t为波导基底110的厚度，λ为入射波长，p为光栅周期，n₀为波导折射率。In formula (I), t is the thickness of the waveguide substrate 110, λ is the incident wavelength, p is the grating period, and _n0 is the waveguide refractive index.

上述步骤中，第一耦出块132指的是第一子耦出区域131中的任意第一耦出块132，第一耦出块132沿第一方向的实际长度可以略大于或者略小于n*d的具体数值。当某一第一耦出块132沿第一方向的长度基于上述步骤得到之后，计算相邻第一耦出块132沿第一方向的长度的方法等同于上述原理。In the above steps, the first coupling block 132 refers to any first coupling block 132 in the first sub-coupling region 131, and the actual length of the first coupling block 132 along the first direction can be slightly greater than or slightly less than the specific value of n*d. After the length of a certain first coupling block 132 along the first direction is obtained based on the above steps, the method for calculating the length of adjacent first coupling blocks 132 along the first direction is equivalent to the above principle.

在前述实施方式的基础上，第二耦出块134沿垂直于第一方向的宽度基于图像光线在第二耦出块134内的预设截止效率阈值得到，第二耦出块134沿第一方向的长度等于第一子耦出区域131沿第一方向的长度。Based on the foregoing implementation, the width of the second outcoupling block 134 along the direction perpendicular to the first direction is obtained based on a preset cutoff efficiency threshold of the image light in the second outcoupling block 134, and the length of the second outcoupling block 134 along the first direction is equal to the length of the first sub-outcoupling region 131 along the first direction.

在前述实施方式的基础上，在垂直于第一方向的方向上，至少两个第二耦出块134沿远离第一子耦出区域131方向的宽度递减。当然，本发明的衍射光波导中，在垂直于第一方向的方向上，至少两个第二耦出块134沿远离第一子耦出区域131方向的宽度亦可以相同。On the basis of the above-mentioned embodiment, in the direction perpendicular to the first direction, the widths of at least two second outcoupling blocks 134 in the direction away from the first outcoupling sub-region 131 decrease gradually. Of course, in the diffractive optical waveguide of the present invention, in the direction perpendicular to the first direction, the widths of at least two second outcoupling blocks 134 in the direction away from the first outcoupling sub-region 131 may also be the same.

在前述实施方式的基础上，请一并参见图4，第二耦出块134沿垂直于第一方向(即图4中y方向或者y方向的反方向)的宽度为n*d，n为全反射次数，并基于以下步骤得到：Based on the above implementation, please refer to FIG. 4 , the width of the second outcoupling block 134 along the direction perpendicular to the first direction (i.e., the y direction in FIG. 4 or the opposite direction of the y direction) is n*d, where n is the number of total reflections, and is obtained based on the following steps:

S30、第二耦出块134内设有若干光栅结构，定义初始光栅结构沿垂直于第一方向上向相邻光栅结构的传导效率为a，定义初始光栅结构沿第一方向上向相邻光栅结构的传导效率c；S30, a plurality of grating structures are provided in the second outcoupling block 134, a transmission efficiency of the initial grating structure to the adjacent grating structure along the direction perpendicular to the first direction is defined as a, and a transmission efficiency of the initial grating structure to the adjacent grating structure along the first direction is defined as c;

S40、图像光线在第二耦出块134内的第n次全反射沿垂直于第一方向上的传导效率为a*c^n-1，图像光线在第二耦出块134内的第n次全反射沿第一方向的传导效率为cⁿ，预设图像光线在第二耦出块134内的截止效率阈值为ε，当第n次传导的效率a*b^n-1＜a*ε时结束第二耦出块134，此时第二耦出块134沿垂直于第一方向的宽度为n*d。S40, the transmission efficiency of the image light in the second outcoupling block 134 along the direction perpendicular to the first direction after the n-th total reflection is a*c ^n-1 , the transmission efficiency of the image light in the second outcoupling block 134 along the first direction after the n-th total reflection is c ⁿ , a cutoff efficiency threshold of the image light in the second outcoupling block 134 is preset to be ε, and the second outcoupling block 134 is terminated when the efficiency of the n-th transmission is a*b ^n-1 ＜a*ε, and at this time, the width of the second outcoupling block 134 along the direction perpendicular to the first direction is n*d.

步骤S20中，d为全反射点间距，并基于公式(II)计算得到：d＝t*tan(arcsin(λ/p/n₀))*2*sin(60°) (II)；In step S20, d is the total reflection point spacing, and is calculated based on formula (II): d = t*tan(arcsin(λ/p/n ₀ ))*2*sin(60°) (II);

公式(II)中，t为波导基底110的厚度，λ为入射波长，p为光栅周期，n₀为波导折射率。In formula (II), t is the thickness of the waveguide substrate 110, λ is the incident wavelength, p is the grating period, and _n0 is the waveguide refractive index.

上述步骤中，第二耦出块134指的是第二子耦出区域133中的任意第二耦出块134，第二耦出块134沿垂直于第一方向的实际宽度可以略大于或者略小于n*d的具体数值。当某一第二耦出块134沿垂直于第一方向的宽度基于上述步骤得到之后，计算相邻第二耦出块134沿垂直于第一方向的宽度的方法等同于上述原理。In the above steps, the second coupling block 134 refers to any second coupling block 134 in the second sub-coupling region 133, and the actual width of the second coupling block 134 along the first direction perpendicular to the specific value of n*d can be slightly greater than or slightly less than. After a certain second coupling block 134 is obtained along the width perpendicular to the first direction based on the above steps, the method for calculating the width of adjacent second coupling blocks 134 along the first direction perpendicular to the first direction is equal to the above principle.

进一步地，本发明的衍射光波导的设计可以对整个耦出区域进行效率分区，亦可以只针对部分耦出区域进行效率分区，具体可以根据实际需求进行设置。Furthermore, the design of the diffractive optical waveguide of the present invention can partition the efficiency of the entire outcoupling area, or can partition the efficiency of only part of the outcoupling area, which can be specifically configured according to actual needs.

此外，本发明的衍射光波导可以采用若干种不同的制备方法进行制备。Furthermore, the diffractive optical waveguide of the present invention can be fabricated using a number of different fabrication methods.

请参见图5，本发明第一实施方式的衍射光波导的制备方法，包括如下步骤：Referring to FIG. 5 , the method for preparing a diffractive optical waveguide according to the first embodiment of the present invention comprises the following steps:

步骤一：先通过两束光(图5中箭头光束照射方向)干涉的方式，在涂有光敏胶140的波导基底110表面曝光，累计曝光能量，初步在耦出区域整面形成均匀的干涉能量面。Step 1: First, two beams of light (in the direction of the arrow beams in FIG. 5 ) are interfered to expose the surface of the waveguide substrate 110 coated with the photosensitive adhesive 140, and the exposure energy is accumulated to initially form a uniform interference energy surface on the entire surface of the outcoupling area.

步骤二：根据理论计算与仿真设定耦出块各分区布局。Step 2: Set the layout of each partition of the coupling block according to theoretical calculation and simulation.

步骤三：建立结构参数与光刻参数的映射模型，根据耦出块150(可以为前述的第一耦出块或者第二耦出块)的分布确定各区域对应立体光刻参数。Step three: Establish a mapping model between structural parameters and lithography parameters, and determine the stereolithography parameters corresponding to each region according to the distribution of the outcoupling block 150 (which may be the first outcoupling block or the second outcoupling block mentioned above).

步骤四：执行区域化立体光刻，在光敏胶140中叠加立体光刻光场能量，且不同耦出块堆积的能量不同。Step 4: Perform regionalized stereolithography to superimpose stereolithography light field energy in the photosensitive resin 140 , and different outcoupling blocks have different accumulated energies.

步骤五：在专用显影液中显影，相同显影时间中，不同能量堆积的区域形成不同参数的结构面型。Step 5: Develop in a special developer. During the same development time, areas with different energy accumulation form structural surfaces with different parameters.

请参见图6，本发明第二实施方式的衍射光波导的制备方法，包括如下步骤：Referring to FIG. 6 , a method for preparing a diffractive optical waveguide according to a second embodiment of the present invention comprises the following steps:

步骤一：根据理论计算与仿真设定耦出块150(可以为前述的第一耦出块或者第二耦出块)各分区布局。Step 1: Setting the layout of each partition of the decoupling block 150 (which may be the first decoupling block or the second decoupling block mentioned above) according to theoretical calculation and simulation.

步骤二：建立耦出块区域划分布局与光刻参数的映射模型，根据耦出块分布确定各区域对应立体光刻参数。Step 2: Establish a mapping model between the decoupling block area division layout and lithography parameters, and determine the corresponding stereolithography parameters of each area according to the decoupling block distribution.

步骤三：执行区域化立体光刻，在光敏胶140中堆积立体光刻光场能量，且不同耦出块堆积的能量不同。Step 3: Perform regionalized stereolithography to accumulate stereolithography light field energy in the photosensitive resin 140 , and different outcoupling blocks accumulate different energies.

步骤四：通过两束光干涉的方式，在涂有光敏胶140的波导基底110表面曝光，累计曝光能量，在耦出区域整面叠加均匀的干涉能量面。Step 4: Expose the surface of the waveguide substrate 110 coated with the photosensitive adhesive 140 by means of interference of two beams of light, accumulate exposure energy, and superimpose a uniform interference energy surface on the entire outcoupling area.

请参见图7，本发明第三实施方式的衍射光波导的制备方法，包括如下步骤：Referring to FIG. 7 , a method for preparing a diffractive optical waveguide according to a third embodiment of the present invention comprises the following steps:

步骤二：建立各分区与干涉曝光剂量的映射模型，即每一块分区有与之对应的曝光时间。Step 2: Establish a mapping model between each partition and the interference exposure dose, that is, each partition has a corresponding exposure time.

步骤三：通过两束光干涉的方式，在涂有光敏胶的基底表面曝光，累计曝光能量，在耦出区域叠加干涉能量面。Step 3: Expose the surface of the substrate coated with photosensitive adhesive by means of interference of two beams of light, accumulate exposure energy, and superimpose the interference energy surface in the outcoupling area.

但需要注意的是，根据不同耦出块150对应的曝光时间，进行光阑式控制，光阑160可以是镂空的，也可以是对曝光光源存在透过率可调；不同的耦出块150的曝光剂量，通过控制光阑160的位置、大小或透过率进行精确控制。However, it should be noted that according to the exposure time corresponding to different coupling blocks 150, aperture control is performed, and the aperture 160 can be hollow or have adjustable transmittance for the exposure light source; the exposure dose of different coupling blocks 150 is precisely controlled by controlling the position, size or transmittance of the aperture 160.

请参见图8，一实施方式的光阑式曝光的设计，图8中耦出块151、152、153以及154为不同的耦出块，即代表这四块区域内的曝光剂量不同，则可以看到图7所示的镂空光阑170进行位移控制，或采用不同透过率的光阑160，进行全幅面精确曝光。Please refer to Figure 8, which is a design of an aperture type exposure in one embodiment. The coupling blocks 151, 152, 153 and 154 in Figure 8 are different coupling blocks, which means that the exposure doses in these four areas are different. It can be seen that the hollow aperture 170 shown in Figure 7 is used for displacement control, or the aperture 160 with different transmittance is used to perform full-frame precise exposure.

上述各实施方式的衍射光波导的制备方法工艺简单，制备得到的衍射光波导能够对耦出区域进行效率分区，从而合理分配单位面积的衍射能量，均衡耦出区域内不同位置的衍射效率，从而提升眼盒范围内不同观察图像亮度均匀性，有利于广泛应用。The preparation method of the diffraction optical waveguide of each of the above-mentioned embodiments is simple in process, and the prepared diffraction optical waveguide can partition the out-coupling area for efficiency, thereby reasonably distributing the diffraction energy per unit area and balancing the diffraction efficiency at different positions in the out-coupling area, thereby improving the brightness uniformity of different observation images within the eye box range, which is conducive to wide application.

一实施方式的显示模组，包括上述任一的衍射光波导。进一步地，显示模组为抬头显示模组或者增强现实可穿戴显示模组。其中，增强现实可穿戴显示模组可以为增强现实近眼显示模组等。A display module of an embodiment includes any of the above-mentioned diffractive optical waveguides. Further, the display module is a head-up display module or an augmented reality wearable display module. Among them, the augmented reality wearable display module can be an augmented reality near-eye display module, etc.

请参见图9，一实施方式的抬头显示模组200包括上述任一实施方式的衍射光波导100。光源组件向衍射光波导100发射光，衍射光波导100将光沿图9中箭头方向经过耦入扩瞳传输再耦出至车的挡风玻璃220上，进而通过挡风玻璃220的反射进入人眼中进行成像。由于抬头显示模组200是设置在汽车中的，抬头显示模组200的成像光是通过汽车的挡风玻璃220反射至人眼的，挡风玻璃220是透明的即可观察到真实世界中的信息。通过抬头显示模组200将成像光反射到挡风玻璃220处，使得抬头显示模组200的成像面与真实世界中的信息产生叠加，使得用户不需低头就能够观察到仪表盘上的信息，提高了便利性。同时本发明的抬头显示模组具有传输效率高和成像效果佳的优点，使得用户能更清楚地观察到抬头显示模组所显示的信息，大大提高了用户的使用满意度。Please refer to FIG9 , a head-up display module 200 of an embodiment includes a diffractive optical waveguide 100 of any of the above embodiments. The light source assembly emits light to the diffractive optical waveguide 100, and the diffractive optical waveguide 100 couples the light along the direction of the arrow in FIG9 through the coupling-in pupil expansion transmission and then couples the light out to the windshield 220 of the car, and then enters the human eye through the reflection of the windshield 220 to form an image. Since the head-up display module 200 is set in the car, the imaging light of the head-up display module 200 is reflected to the human eye through the windshield 220 of the car, and the windshield 220 is transparent, so that the information in the real world can be observed. The imaging light is reflected to the windshield 220 by the head-up display module 200, so that the imaging surface of the head-up display module 200 is superimposed with the information in the real world, so that the user can observe the information on the dashboard without lowering his head, which improves the convenience. At the same time, the head-up display module of the present invention has the advantages of high transmission efficiency and good imaging effect, so that the user can observe the information displayed by the head-up display module more clearly, which greatly improves the user's satisfaction.

请参见图10，一实施方式的增强现实可穿戴显示模组300包括上述任一实施方式的衍射光波导100，衍射光波导100包括耦出区域130。本实施方式的增强现实可穿戴显示模组300为增强现实近眼显示模组，具体为AR眼镜，当然，增强现实可穿戴显示模组300不限于此，还可以为其他形式，例如头盔等。Referring to FIG. 10 , an augmented reality wearable display module 300 of an embodiment includes the diffractive optical waveguide 100 of any of the above embodiments, and the diffractive optical waveguide 100 includes an outcoupling region 130. The augmented reality wearable display module 300 of this embodiment is an augmented reality near-eye display module, specifically AR glasses. Of course, the augmented reality wearable display module 300 is not limited thereto, and may also be in other forms, such as a helmet.

应用本实施方式的增强现实可穿戴显示模组300，图像光线沿图10中箭头方向通过衍射光波导100的耦出区域130出射被人眼接收，且因为衍射光波导的透明属性，人眼在现实空间可以观看到虚拟图像，并实现融合。由于本发明的密度渐变衍射光波导，可在耦出区域对应的眼盒范围内实现能量的均衡出射，因此提升了增强现实可穿戴显示模组的显示质量。Using the augmented reality wearable display module 300 of this embodiment, the image light is emitted along the arrow direction in FIG10 through the coupling-out region 130 of the diffraction light waveguide 100 and received by the human eye, and because of the transparent property of the diffraction light waveguide, the human eye can see the virtual image in the real space and achieve fusion. Due to the density gradient diffraction light waveguide of the present invention, the energy can be evenly emitted within the eye box range corresponding to the coupling-out region, thereby improving the display quality of the augmented reality wearable display module.

参照上述实施内容，为了使得本申请的技术方案更加具体清楚、易于理解，现对本申请技术方案进行举例，但是需要说明的是，本申请所要保护的内容不限于以下实施例1和实施例2。With reference to the above implementation contents, in order to make the technical solution of the present application more specific, clear and easy to understand, the technical solution of the present application is now exemplified. However, it should be noted that the contents to be protected by the present application are not limited to the following Examples 1 and 2.

实施例1Example 1

请参见图11，实施例1的衍射光波导400包括波导基底410，波导基底410包括耦入区域420和位于耦入区域420一侧的耦出区域430。其中，自耦入区域420向耦出区域430的方向为第一方向(即图11中x方向)，耦出区域430包括第一子耦出区域440和分别位于第一子耦出区域440两侧的两个第二子耦出区域450，且两个第二子耦出区域450关于第一子耦出区域440对称分布。Please refer to FIG11 , the diffractive optical waveguide 400 of Example 1 includes a waveguide substrate 410, and the waveguide substrate 410 includes an in-coupling region 420 and an out-coupling region 430 located on one side of the in-coupling region 420. The direction from the in-coupling region 420 to the out-coupling region 430 is a first direction (i.e., the x direction in FIG11 ), and the out-coupling region 430 includes a first sub-out-coupling region 440 and two second sub-out-coupling regions 450 located on both sides of the first sub-out-coupling region 440, and the two second sub-out-coupling regions 450 are symmetrically distributed about the first sub-out-coupling region 440.

其中，第一子耦出区域440包括沿第一方向依次设置的三个第一耦出块441、442和443。第一耦出块441、442和443沿垂直于第一方向(即图11中y方向或者y方向的反方向)的宽度以及沿第一方向的长度均不小于进入耦入区域420的光斑宽度，三个第一耦出块441、442和443的效率调制功能沿第一方向呈递进趋势，且三个第一耦出块441、442和443沿第一方向的长度递减。The first sub-coupling region 440 includes three first coupling blocks 441, 442 and 443 arranged in sequence along the first direction. The width of the first coupling blocks 441, 442 and 443 along the first direction perpendicular to the first direction (i.e., the y direction in FIG. 11 or the opposite direction of the y direction) and the length along the first direction are not less than the width of the light spot entering the coupling region 420, and the efficiency modulation functions of the three first coupling blocks 441, 442 and 443 are progressive along the first direction, and the lengths of the three first coupling blocks 441, 442 and 443 along the first direction decrease.

其中，在垂直于第一方向的方向(即图11中y方向或者y方向的反方向)上，第二子耦出区域450包括沿远离第一子耦出区域440的方向依次设置的两个第二耦出块451和452，两个第二耦出块451和452的效率调制功能沿远离第一子耦出区域440的方向呈递进趋势，且在垂直于第一方向的方向上，两个第二耦出块451和452沿远离第一子耦出区域440方向的宽度递减。Among them, in the direction perpendicular to the first direction (i.e., the y direction in Figure 11 or the opposite direction of the y direction), the second sub-coupling area 450 includes two second coupling blocks 451 and 452 arranged in sequence along the direction away from the first sub-coupling area 440, and the efficiency modulation functions of the two second coupling blocks 451 and 452 show a progressive trend along the direction away from the first sub-coupling area 440, and in the direction perpendicular to the first direction, the widths of the two second coupling blocks 451 and 452 decrease along the direction away from the first sub-coupling area 440.

对实施例1的衍射光波导400进行仿真，设定入射光束直径为9.5mm；第一耦出块441的周期为440nm，深度为50nm，占空比为0.5；第一耦出块442的周期为440nm，深度为100nm，占空比为0.5；第一耦出块443的周期为440nm，深度为200nm，占空比为0.5；第二耦出块451的周期为440nm，深度为150nm，占空比为0.5；第二耦出块452的周期为440nm，深度为200nm，占空比为0.5。具体的耦出区域430的光强度如图12所示，从图12可以看出，实施例1的衍射光波导400能够较为明显的具备整个耦出区域均匀度的提升，同时极大值与极小值的差异也一定程度的收缩。The diffraction optical waveguide 400 of Example 1 is simulated, and the incident beam diameter is set to 9.5 mm; the period of the first coupling block 441 is 440 nm, the depth is 50 nm, and the duty cycle is 0.5; the period of the first coupling block 442 is 440 nm, the depth is 100 nm, and the duty cycle is 0.5; the period of the first coupling block 443 is 440 nm, the depth is 200 nm, and the duty cycle is 0.5; the period of the second coupling block 451 is 440 nm, the depth is 150 nm, and the duty cycle is 0.5; the period of the second coupling block 452 is 440 nm, the depth is 200 nm, and the duty cycle is 0.5. The specific light intensity of the coupling area 430 is shown in Figure 12. It can be seen from Figure 12 that the diffraction optical waveguide 400 of Example 1 can significantly improve the uniformity of the entire coupling area, and the difference between the maximum and minimum values is also reduced to a certain extent.

实施例2Example 2

请参见图13，实施例2的衍射光波导500包括波导基底510，波导基底510包括耦入区域520和位于耦入区域520一侧的耦出区域530。其中，自耦入区域520向耦出区域530的方向为第一方向(即图13中x方向)，耦出区域530包括第一子耦出区域540和分别位于第一子耦出区域540两侧的两个第二子耦出区域550，且两个第二子耦出区域550关于第一子耦出区域540对称分布。Please refer to FIG. 13 , the diffractive optical waveguide 500 of Embodiment 2 includes a waveguide substrate 510, and the waveguide substrate 510 includes a coupling-in region 520 and a coupling-out region 530 located on one side of the coupling-in region 520. The direction from the coupling-in region 520 to the coupling-out region 530 is a first direction (i.e., the x direction in FIG. 13 ), and the coupling-out region 530 includes a first sub-coupling region 540 and two second sub-coupling regions 550 located on both sides of the first sub-coupling region 540, and the two second sub-coupling regions 550 are symmetrically distributed about the first sub-coupling region 540.

其中，第一子耦出区域540包括沿第一方向依次设置的三个第一耦出块541、542、543和544。第一耦出块541、542、543和544沿垂直于第一方向(即图13中y方向或者y方向的反方向)的宽度以及沿第一方向的长度均不小于进入耦入区域520的光斑宽度，三个第一耦出块541、542、543和544的效率调制功能沿第一方向呈递进趋势，且三个第一耦出块541、542、543和544沿第一方向的长度递减。The first sub-coupling region 540 includes three first coupling blocks 541, 542, 543 and 544 arranged in sequence along the first direction. The width of the first coupling blocks 541, 542, 543 and 544 along the first direction perpendicular to the first direction (i.e., the y direction or the opposite direction of the y direction in FIG. 13) and the length along the first direction are not less than the width of the light spot entering the coupling region 520, and the efficiency modulation functions of the three first coupling blocks 541, 542, 543 and 544 are progressive along the first direction, and the lengths of the three first coupling blocks 541, 542, 543 and 544 along the first direction decrease.

其中，在垂直于第一方向的方向(即图13中y方向或者y方向的反方向)上，第二子耦出区域550包括沿远离第一子耦出区域540的方向依次设置的七个第二耦出块551、552、553、554、555、556和557，七个第二耦出块551、552、553、554、555、556和557的效率调制功能沿远离第一子耦出区域540的方向呈递进趋势，且在垂直于第一方向的方向上，七个第二耦出块551、552、553、554、555、556和557沿远离第一子耦出区域540方向的宽度递减。Among them, in the direction perpendicular to the first direction (i.e., the y direction in Figure 13 or the opposite direction of the y direction), the second sub-coupling area 550 includes seven second coupling blocks 551, 552, 553, 554, 555, 556 and 557 arranged in sequence along the direction away from the first sub-coupling area 540, and the efficiency modulation functions of the seven second coupling blocks 551, 552, 553, 554, 555, 556 and 557 are progressive in the direction away from the first sub-coupling area 540, and in the direction perpendicular to the first direction, the widths of the seven second coupling blocks 551, 552, 553, 554, 555, 556 and 557 decrease along the direction away from the first sub-coupling area 540.

对实施例2的衍射光波导500进行仿真，设定入射光束直径为9.5mm，入射角为0度，各耦出块的参数如表1。The diffraction optical waveguide 500 of Example 2 is simulated, and the incident light beam diameter is set to 9.5 mm, the incident angle is set to 0 degrees, and the parameters of each coupling block are shown in Table 1.

表1实施例2的衍射光波导在入射角0度、-5度和5度时的结构参数 Table 1 Structural parameters of the diffraction optical waveguide of Example 2 at incident angles of 0 degrees, -5 degrees and 5 degrees

实施例2的衍射光波导分别在入射角0度、-5度和5度时的光强度依次如图14～图16所示。从图14～图16可以看出，当入射角为0度、-5度和5度时，耦出区域出射效率均呈现较为均匀的现象，从靠近耦入区域一端至远离耦入区域一端，强度变化均不明显。The light intensities of the diffractive optical waveguide of Example 2 at incident angles of 0, -5 and 5 degrees are shown in Figures 14 to 16, respectively. It can be seen from Figures 14 to 16 that when the incident angles are 0, -5 and 5 degrees, the output efficiency of the out-coupling region is relatively uniform, and the intensity changes from one end close to the in-coupling region to the end far from the in-coupling region are not obvious.

对比例1Comparative Example 1

请参见图17，对比例1的衍射光波导200’包括波导基底210’，波导基底210’包括耦入区域220’与耦出区域230’，耦入区域220’与耦出区域230’在x方向与y方向均未做分区处理，即耦出区域230’整幅面内的纳米结构覆盖为同一光学调制特性的结构。依据图17所示的结构，当耦入区域220’承接入射光线时，基于耦入区域220’的纳米结构光线耦合特性，其入射光会耦合进入波导基底210’，并向耦出区域230’传导，经耦出区域230’的纳米结构进行扩瞳与光线出射。Please refer to FIG. 17 , the diffraction optical waveguide 200 'of comparative example 1 includes a waveguide substrate 210 ', and the waveguide substrate 210 ' includes an incoupling region 220 ' and an outcoupling region 230 ', and the incoupling region 220 ' and the outcoupling region 230 ' are not partitioned in the x direction and the y direction, that is, the nanostructures in the entire surface of the outcoupling region 230 ' are covered with a structure with the same optical modulation characteristics. According to the structure shown in FIG. 17 , when the incoupling region 220 ' receives incident light, based on the light coupling characteristics of the nanostructure of the incoupling region 220 ', the incident light will be coupled into the waveguide substrate 210 ', and transmitted to the outcoupling region 230 ', and the pupil will be expanded and the light will be emitted through the nanostructure of the outcoupling region 230 '.

对比例1的衍射光波导200’中，耦入区域220’采用一维光栅，耦出区域230’采用二维点阵结构，一维光栅与二维点阵的周期均设为400nm，深度设为200nm，占空比设为0.5。基于光线追迹算法，得出如图18所示的光线出射仿真图。可以看出，光线在耦出区域230’的传导过程，出射光线的数量逐渐减少，代表出瞳的光能量逐渐减少，耦出区域230’的整体能量出射的严重不均匀。图18所示的光强度仿真，是耦出区域230’未做变化去适配均匀性的结果，其结果是不理想的，整块耦出区域230’的光强度分布是严重不均匀的，这必然会带来很差的显示体验。In the diffraction optical waveguide 200' of comparative example 1, the coupling-in region 220' adopts a one-dimensional grating, and the coupling-out region 230' adopts a two-dimensional lattice structure. The period of the one-dimensional grating and the two-dimensional lattice are both set to 400nm, the depth is set to 200nm, and the duty cycle is set to 0.5. Based on the ray tracing algorithm, the light emission simulation diagram shown in Figure 18 is obtained. It can be seen that during the conduction process of the light in the coupling-out region 230', the number of emitted light rays gradually decreases, the light energy representing the exit pupil gradually decreases, and the overall energy emission of the coupling-out region 230' is seriously uneven. The light intensity simulation shown in Figure 18 is the result that the coupling-out region 230' has not been changed to adapt to the uniformity, and the result is not ideal. The light intensity distribution of the entire coupling-out region 230' is seriously uneven, which will inevitably bring a very poor display experience.

对比例2Comparative Example 2

请参见图19，对比例2的衍射光波导300’包括波导基底310’，波导基底310’包括耦入区域320’与耦出区域330’，耦出区域330’包括沿x方向依次排布的第一耦出块331’、第二耦出块332’与第三耦出块333’。其中，第一耦出块331’、第二耦出块332’与第三耦出块333’的光学调制效率特性不同，理解为第一耦出块331’的光能利用率小于第二耦出块332’的光能利用率小于第三耦出块332’的光能利用率。Please refer to Fig. 19, the diffraction optical waveguide 300' of comparative example 2 includes a waveguide substrate 310', the waveguide substrate 310' includes a coupling-in region 320' and a coupling-out region 330', and the coupling-out region 330' includes a first coupling-out block 331', a second coupling-out block 332' and a third coupling-out block 333' arranged in sequence along the x direction. Among them, the optical modulation efficiency characteristics of the first coupling-out block 331', the second coupling-out block 332' and the third coupling-out block 333' are different, which means that the light energy utilization rate of the first coupling-out block 331' is less than that of the second coupling-out block 332' and that of the third coupling-out block 332'.

对比例2的衍射光波导300’中，耦入区域320’采用一维光栅，耦出区域330’采用二维点阵结构；第一耦出块331’中纳米结构的周期设为440nm，深度设为50nm，占空比设为0.5；第二耦出块332’中纳米结构设为440nm，深度设为100nm，占空比设为0.5；第三耦出块333’中纳米结构设为440nm，深度设为200nm，占空比设为0.5。基于光线追迹算法，得出如图20所示的光线出射仿真图。从图20可以看出，光线在耦出区域330’的传导过程，出射光线的能量分布较之对比例1的衍射光波导的结果明显改善，耦出区域330’对应的眼盒范围的均匀性得到改善，但由于分布设计单一，仍然存在明显的明暗的分别，即代表了整幅面的均匀性仍然不够好。In the diffraction optical waveguide 300' of comparative example 2, the coupling-in region 320' adopts a one-dimensional grating, and the coupling-out region 330' adopts a two-dimensional lattice structure; the period of the nanostructure in the first coupling-out block 331' is set to 440nm, the depth is set to 50nm, and the duty cycle is set to 0.5; the nanostructure in the second coupling-out block 332' is set to 440nm, the depth is set to 100nm, and the duty cycle is set to 0.5; the nanostructure in the third coupling-out block 333' is set to 440nm, the depth is set to 200nm, and the duty cycle is set to 0.5. Based on the ray tracing algorithm, the light emission simulation diagram shown in Figure 20 is obtained. It can be seen from Figure 20 that in the conduction process of the light in the coupling-out region 330', the energy distribution of the outgoing light is significantly improved compared with the result of the diffraction optical waveguide of comparative example 1, and the uniformity of the eye box range corresponding to the coupling-out region 330' is improved, but due to the single distribution design, there is still a clear difference in light and dark, which means that the uniformity of the entire surface is still not good enough.

以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

以上所述实施例仅表达了本发明的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本发明构思的前提下，还可以做出若干变形和改进，这些都属于本发明的保护范围。因此，本发明专利的保护范围应以所附权利要求为准。The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

A diffractive optical waveguide, characterized in that the diffractive optical waveguide comprises a waveguide substrate, the waveguide substrate comprises an incoupling region and an outcoupling region located on one side of the incoupling region, the incoupling region is used to couple image light into the waveguide substrate, and the outcoupling region is used to couple out the image light conducted in the waveguide substrate;

The direction from the coupling-in region to the coupling-out region is a first direction, the coupling-out region includes a first sub-coupling region and a second sub-coupling region, the first sub-coupling region is arranged close to the coupling-in region, and the second sub-coupling region is arranged away from the coupling-in region along a direction perpendicular to the first direction;

The first sub-coupling region includes at least two first coupling blocks arranged in sequence along the first direction, and the efficiency modulation functions of the at least two first coupling blocks are in a progressive trend along the first direction;

In a direction perpendicular to the first direction, the second sub-coupling region includes at least two second outcoupling blocks arranged in sequence along a direction away from the first sub-coupling region, and the efficiency modulation functions of the at least two second outcoupling blocks show a progressive trend along the direction away from the first sub-coupling region.

The diffractive optical waveguide according to claim 1, characterized in that the number of the second sub-coupling regions is two, and the two second sub-coupling regions are symmetrically distributed about the first sub-coupling region.

The diffractive optical waveguide according to claim 1 or 2 is characterized in that the width of the first outcoupling block along the first direction perpendicular to the first direction is not less than the width of the light spot entering the coupling-in region, and the length of the first outcoupling block along the first direction is obtained based on a preset cutoff efficiency threshold of the image light in the first outcoupling block.

The diffractive optical waveguide according to claim 3, characterized in that the lengths of at least two of the first outcoupling blocks along the first direction decrease gradually.

The diffractive optical waveguide according to claim 3, characterized in that the length of the first outcoupling block along the first direction is n*d, where n is the number of total reflections, and is obtained based on the following steps:

A plurality of grating structures are provided in the first outcoupling block, a transmission efficiency of an initial grating structure to an adjacent grating structure along a direction perpendicular to the first direction is defined as a, and a transmission efficiency of an initial grating structure to an adjacent grating structure along the first direction is defined as b; and

The transmission efficiency of the image light in the first outcoupling block in the direction perpendicular to the first direction after the n-th total reflection is a* ^bn-1 , the transmission efficiency of the image light in the first outcoupling block in the direction perpendicular to the first direction after the n-th total reflection is ^bn , the cutoff efficiency threshold of the image light in the first outcoupling block is preset to be ε, and the first outcoupling block is terminated when the efficiency of the n-th transmission is a* ^bn-1 <a*ε, and at this time, the length of the first outcoupling block in the first direction is n*d;

Where d is the total reflection point spacing, and is calculated based on formula (I):
d=t*tan(arcsin(λ/p/n ₀ ))*2 (I);

In formula (I), t is the thickness of the waveguide substrate, λ is the incident wavelength, p is the grating period, and _n0 is the waveguide refractive index.

The diffractive optical waveguide according to claim 1 or 2, characterized in that the width of the second outcoupling block along the direction perpendicular to the first direction is obtained based on a preset cutoff efficiency threshold of the image light in the second outcoupling block, and the length of the second outcoupling block along the first direction is equal to the length of the first sub-outcoupling region along the first direction.

The diffractive optical waveguide according to claim 6, characterized in that, in a direction perpendicular to the first direction, the widths of at least two of the second outcoupling blocks decrease gradually along a direction away from the first sub-outcoupling region.

The diffractive optical waveguide according to claim 6, characterized in that the width of the second outcoupling block along the direction perpendicular to the first direction is n*d, where n is the number of total reflections, and is obtained based on the following steps:

The second outcoupling block is provided with a plurality of grating structures, and the transmission efficiency of the initial grating structure to the adjacent grating structure along the first direction perpendicular to the first direction is defined as a, and the transmission efficiency of the initial grating structure to the adjacent grating structure along the first direction is defined as c; and

The transmission efficiency of the image light in the second outcoupling block in the direction perpendicular to the first direction during the n-th total reflection is a*c ^n-1 , the transmission efficiency of the image light in the second outcoupling block in the direction perpendicular to the first direction during the n-th total reflection is c ⁿ , the cutoff efficiency threshold of the image light in the second outcoupling block is preset to be ε, and the second outcoupling block is terminated when the efficiency of the n-th transmission is a*b ^n-1 ＜a*ε, and at this time, the width of the second outcoupling block in the direction perpendicular to the first direction is n*d;

Where d is the total reflection point spacing, and is calculated based on formula (II):
d＝t*tan(arcsin(λ/p/n ₀ ))*2*sin(60°) (II);

In formula (II), t is the thickness of the waveguide substrate, λ is the incident wavelength, p is the grating period, and _n0 is the waveguide refractive index.

A display module, characterized by comprising the diffraction light waveguide according to any one of claims 1 to 8.

The display module according to claim 9 is characterized in that the display module is a head-up display module or an augmented reality wearable display module.