WO2022267610A1

WO2022267610A1 - Optical device and electronic device

Info

Publication number: WO2022267610A1
Application number: PCT/CN2022/084904
Authority: WO
Inventors: 丁武文; 鲁云开; 李民康
Original assignee: 华为技术有限公司
Priority date: 2021-06-23
Filing date: 2022-04-01
Publication date: 2022-12-29
Also published as: CN115509006A

Abstract

An optical device (100) and an electronic device (200). The optical device (100) comprises at least one waveguide substrate (104), and a coupling-in unit (101), a first relay unit (1021), a second relay unit (1022) and a coupling-out unit (103) arranged on the waveguide substrate (104). The first relay unit (1021) and the second relay unit (1022) define a relay area enabling a direction of travel of a portion of a light ray coupled in by the coupling-in unit (101) to be limited to fully reflective propagation between the first relay unit (1021) and the second relay unit (1022) after entering the waveguide substrate (104), and another portion of the light ray may be redirected at the second relay unit (1022) towards the coupling-out unit (103) for fully reflective propagation. When a light ray which is fully reflected towards the coupling-out unit (103) reaches the coupling-out unit (103), a portion of the light ray continues to be fully reflected in the original direction and another portion is coupled out to a human eye. In this way, it is possible to expand an exit pupil of a light ray in two dimensions without increasing the area of a relay grating while increasing an image edge field of view angle.

Description

光学设备及电子设备Optical equipment and electronic equipment

本申请要求于2021年06月23日提交中国专利局、申请号为202110699966.9、申请名称为“光学设备及电子设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。This application claims the priority of a Chinese patent application with application number 202110699966.9 and application title "Optical Device and Electronic Device" filed with the China Patent Office on June 23, 2021, the entire contents of which are incorporated herein by reference.

技术领域technical field

本申请涉及增强现实技术领域，特别涉及一种光学设备及电子设备。The present application relates to the field of augmented reality technology, in particular to an optical device and an electronic device.

背景技术Background technique

增强现实(Augmented Reality，AR)技术作为一种将虚拟信息与真实世界巧妙融合的技术，已经广泛应用于军事、商业、工业、消防和娱乐应用等各个领域。Augmented reality (Augmented Reality, AR) technology, as a technology that ingeniously integrates virtual information with the real world, has been widely used in various fields such as military, commercial, industrial, fire protection and entertainment applications.

AR技术主要以微型显示器为图像源，通过光学元件将图像投射入人眼成像。其中，光学元件一般采用光波导结构。AR technology mainly uses microdisplays as image sources, and projects images into human eyes for imaging through optical components. Among them, the optical element generally adopts an optical waveguide structure.

例如，AR技术可以应用于头戴式AR眼镜中，头戴式AR眼镜包括微型显示器及镜片，其中，镜片一般采用光波导结构；微型显示器发出的虚拟图像能够通过光波导结构制成的镜片投射入人眼成像，且光波导结构为透明结构，能够使观察者能够同时观察周围的真实镜像及微型显示器传递的虚拟图像。For example, AR technology can be applied to head-mounted AR glasses. Head-mounted AR glasses include microdisplays and lenses. The lenses generally use optical waveguide structures; virtual images emitted by microdisplays can be projected through lenses made of optical waveguide structures. Imaging into the human eye, and the optical waveguide structure is a transparent structure, enabling the observer to simultaneously observe the real mirror image around and the virtual image transmitted by the microdisplay.

目前AR眼镜中采用的光波导结构一般为在一个方向上进行扩瞳，即在一个方向上看到更大的图像范围，难以适用于不同瞳距、不同脸型及不同鼻梁高度的人群。At present, the optical waveguide structure used in AR glasses generally expands the pupil in one direction, that is, a larger image range can be seen in one direction, which is difficult to apply to people with different interpupillary distances, different face shapes, and different nose bridge heights.

发明内容Contents of the invention

本申请实施例提供了一种光学设备及电子设备。本申请实施例提供的光学设备能够实现在二维方向的出瞳扩展，使得能够用户在二维方向上看到更大的图像范围，且可以适用于不同瞳距、不同脸型及不同鼻梁高度的人群。The embodiment of the present application provides an optical device and an electronic device. The optical device provided by the embodiment of the present application can realize the expansion of the exit pupil in the two-dimensional direction, so that the user can see a larger image range in the two-dimensional direction, and can be applied to people with different interpupillary distances, different face shapes and different nose bridge heights. crowd.

另外，本申请实施例提供的光学设备能够使得在增大图像边缘视场之间的夹角的时候，不用增大传统的中继光栅的面积也可实现x方向的出瞳扩展，能够在较大视场角的情况下有效减小波导衬底的面积，进而减小整个光学设备的面积；且能够满足现有电子设备对大视场角的需求。In addition, the optical device provided by the embodiment of the present application can realize the expansion of the exit pupil in the x direction without increasing the area of the traditional relay grating when increasing the included angle between the peripheral fields of view of the image. In the case of a large viewing angle, the area of the waveguide substrate is effectively reduced, thereby reducing the area of the entire optical device; and the requirement of the existing electronic device for a large viewing angle can be met.

第一方面，本申请实施例提供了一种光学设备，包括至少一个波导衬底，以及设置于所述波导衬底上的耦入单元、第一中继单元、第二中继单元、以及耦出单元；In the first aspect, an embodiment of the present application provides an optical device, including at least one waveguide substrate, and a coupling unit, a first relay unit, a second relay unit, and a coupling unit disposed on the waveguide substrate. out unit;

所述耦入单元被配置为将光线耦入所述波导衬底中；The coupling unit is configured to couple light into the waveguide substrate;

所述第一中继单元和第二中继单元限定出中继区域，所述中继区域在第一方向延伸，所述第一中继单元和第二中继单元在第二方向排列，所述中继区域在所述第二方向上具有相对的第一边和第二边，所述第一边的延伸方向与所述第二边的延伸方向之间夹角小于第一角度；The first relay unit and the second relay unit define a relay area, the relay area extends in a first direction, the first relay unit and the second relay unit are arranged in a second direction, the The relay area has a first side and a second side opposite to each other in the second direction, and the angle between the extension direction of the first side and the extension direction of the second side is smaller than the first angle;

所述耦出单元被配置为将所述波导衬底中的光线耦出所述波导衬底，所述耦出单元与所述中继区域在所述第二方向排列。The outcoupling unit is configured to couple light in the waveguide substrate out of the waveguide substrate, and the outcoupling unit and the relay region are arranged in the second direction.

例如，上述第一方向可以为后文实施例中提及的x轴方向，第二方向可以为后文实施例中提及的y轴方向。For example, the above-mentioned first direction may be the x-axis direction mentioned in the later embodiments, and the second direction may be the y-axis direction mentioned in the later embodiments.

可以理解，本申请实施例提供的光学设备包括第一中继单元和第二中继单元，且第一中继单元和第二中继单元限定有中继区域，能够使得被耦入单元耦入的光线在进入波导衬底之后光线一部分的行径方向被限制在第一中继单元和第二中继单元之间进行全反射式传播，另一部分光线可以在靠近耦出单元的第二中继单元处被改变方向，朝着耦出单元全反射行径，实现x轴的出瞳扩展。It can be understood that the optical device provided in the embodiment of the present application includes a first relay unit and a second relay unit, and the first relay unit and the second relay unit define a relay area, so that the coupled-in unit can be coupled into After the light enters the waveguide substrate, the travel direction of part of the light is restricted between the first relay unit and the second relay unit for total reflection propagation, and the other part of the light can be transmitted in the second relay unit close to the outcoupling unit. The direction is changed, toward the outcoupling unit total reflection, to achieve the exit pupil expansion of the x-axis.

例如，光学设备可以是后文中的衍射光波导，耦入单元可以是后文中的耦入光栅，耦出单元可以是后文中的耦出光栅，第一中继单元可以是后文中的第一中继光栅，第二中继单元可以是后文中的第二中继光栅，中继区域可以由后文中第一中继光栅和第二中继光栅靠近的栅线界定，是第一中继光栅和第二中继光栅之间的区域，不包括第一中继光栅和第二中继光栅。中继区域也可以由第一中继光栅和第二中继光栅相距最远的栅线界定，不仅包括第一中继光栅和第二中继光栅之间的区域，还包括第一中继光栅和第二中继光栅。For example, the optical device can be the diffractive optical waveguide hereinafter, the coupling unit can be the coupling grating hereinafter, the outcoupling unit can be the outcoupling grating hereinafter, and the first relay unit can be the first intermediate grating hereinafter Relay grating, the second relay unit can be the second relay grating hereinafter, the relay area can be defined by the grating lines close to the first relay grating and the second relay grating hereinafter, it is the first relay grating and the second relay grating The area between the second relay gratings does not include the first relay gratings and the second relay gratings. The relay area can also be delimited by the furthest distance between the first relay grating and the second relay grating, including not only the area between the first relay grating and the second relay grating, but also the first relay grating and a second relay grating.

此外，本申请实施例中，采用光线在第一中继单元和第二中继单元间全反射传播的方式实现x方向的出瞳扩展；而不是在中继单元以直线传播的方式实现x方向的出瞳扩展，能够使得在增大图像边缘视场之间的夹角的时候，不用增大传统的中继光栅的面积也可实现x方向的出瞳扩展，能够在较大视场角的情况下有效减小波导衬底的面积，进而减小整个光学设备的面积；且能够满足现有电子设备对大视场角的需求。In addition, in the embodiment of the present application, the exit pupil expansion in the x direction is realized by the way of total reflection and propagation of light between the first relay unit and the second relay unit; The exit pupil expansion can make the expansion of the exit pupil in the x direction possible without increasing the area of the traditional relay grating when increasing the angle between the field of view at the edge of the image. Under the circumstances, the area of the waveguide substrate is effectively reduced, thereby reducing the area of the entire optical device; and it can meet the requirements of the existing electronic devices for a large viewing angle.

此外，朝着耦出单元全反射行径的光线在遇到耦出单元时，一部分光线会沿着原方向继续全反射行径，另一部分被耦出人眼，如此反复实现y方向的出瞳扩展。因此，本申请实施例提供的光学设备也能够实现二维方向的出瞳扩展。采用此光学设备使得能够用户在二维方向上看到更大的图像范围，且可以适用于不同瞳距、不同脸型及不同鼻梁高度的人群。In addition, when the light traveling towards the total reflection of the outcoupling unit encounters the outcoupling unit, part of the light will continue to total reflect along the original direction, and the other part will be coupled out of the human eye, so that the exit pupil expansion in the y direction is achieved repeatedly. Therefore, the optical device provided by the embodiment of the present application can also realize exit pupil expansion in two dimensions. The adoption of the optical device enables users to see a larger image range in two-dimensional directions, and is applicable to people with different interpupillary distances, different face shapes and different nose bridge heights.

在上述第一方面的一种可能的实现中，所述第一角度在0°～5°。In a possible implementation of the first aspect above, the first angle is between 0° and 5°.

在上述第一方面的一种可能的实现中，所述第一边和所述第二边在延伸方向平行。本申请实施例中，所述第一边的延伸方向与所述第二边的延伸方向可以平行设置，也可以有较小误差，例如，所述第一边的延伸方向与所述第二边的延伸方向的夹角可以在0°～5°之间。例如，第一边可以是后文中第一中继光栅的与第二中继光栅最为邻近的栅线，第二边可以是后文中第二中继光栅的与第一中继光栅最为邻近的栅线。In a possible implementation of the first aspect above, the first side and the second side are parallel in an extending direction. In the embodiment of the present application, the extension direction of the first side and the extension direction of the second side may be set in parallel, or there may be a small error, for example, the extension direction of the first side and the second side The included angle of the extending direction of can be between 0° and 5°. For example, the first side may be the grid line closest to the second relay grating of the first relay grating hereinafter, and the second side may be the grid line closest to the first relay grating of the second relay grating hereinafter. Wire.

在上述第一方面的一种可能的实现中，所述第二中继单元被配置为使得所述波导衬底中进行全反射传播的光线在入射到所述第二中继单元后至少部分出射光线朝着所述第一中继单元进行全反射传播，至少部分出射光线朝着所述耦出单元进行全反射传播；In a possible implementation of the above-mentioned first aspect, the second relay unit is configured such that the light propagated through total reflection in the waveguide substrate is at least partially emitted after being incident on the second relay unit The light propagates toward the first relay unit through total reflection, and at least part of the outgoing light propagates toward the outcoupling unit through total reflection;

所述第一中继单元被配置为使得所述波导衬底中全反射传播的光线在入射到所述第一中继单元后出射光线朝着所述第二中继单元进行全反射传播。The first relay unit is configured such that the light propagated through total reflection in the waveguide substrate is incident on the first relay unit, and then the outgoing light propagates toward the second relay unit through total reflection.

例如，以第一中继单元为第一中继光栅，第二中继单元为第二中继光栅为例，所述第二中继单元可以被配置为使得所述波导衬底中全反射传播的光线在入射到所述第二中继单元后至少部分出射光线如图18(a)中B2箭头方向所示，朝着所述第一中继单元进行全反射传播，至少部分出射光线如图18(a)中B3箭头方向所示，朝着所述耦出单元进行全反射传播；For example, taking the first relay unit as a first relay grating and the second relay unit as a second relay grating as an example, the second relay unit can be configured so that the total reflection propagation in the waveguide substrate After the light is incident on the second relay unit, at least part of the outgoing light is shown in the direction of the arrow B2 in Figure 18(a), and it is totally reflected and propagated toward the first relay unit, at least part of the outgoing light is shown in the figure As shown in the direction of the arrow B3 in 18(a), total reflection propagation is carried out towards the outcoupling unit;

所述第一中继单元被配置为使得所述波导衬底中全反射传播的光线在入射到所述第一中继单元后出射光线如图18中B4箭头方向所示，朝着所述第二中继单元进行全反射传播。The first relay unit is configured such that the light propagated through total reflection in the waveguide substrate is incident on the first relay unit and emerges as shown in the direction of arrow B4 in FIG. 18 toward the first relay unit. The second relay unit performs total reflection propagation.

在上述第一方面的一种可能的实现中，所述第一中继单元和第二中继单元为光栅；并且所述中继区域的第一边为所述第一中继单元最靠近所述第二中继单元的栅线，第二边为所述第二中继单元最靠近所述第一中继单元的栅线。即中继区域由第一中继单元和第二中继单元靠近的栅线界定，是第一中继单元和第二中继单元之间的区域，不包括第一中继单元和第二中继单元。例如，可以为后文中图17中所示的第一中继光栅和第二中继光栅的空白区域。In a possible implementation of the first aspect above, the first relay unit and the second relay unit are gratings; and the first side of the relay area is the first relay unit closest to the the gate line of the second relay unit, and the second side is the gate line of the second relay unit closest to the first relay unit. That is to say, the relay area is defined by the grid line close to the first relay unit and the second relay unit, which is the area between the first relay unit and the second relay unit, excluding the first relay unit and the second relay unit. following unit. For example, it may be the blank area of the first relay grating and the second relay grating shown in FIG. 17 hereinafter.

在上述第一方面的一种可能的实现中，所述第一中继单元和第二中继单元为光栅，并且所述中继区域的第一边为所述第一中继单元最远离所述第二中继单元的栅线，第二边为所述第二中继单元最远离所述第一中继单元的栅线。即中继区域由第一中继单元和第二中继单元相距最远的栅线界定，不仅包括第一中继单元和第二中继单元之间的区域，还包括第一中继单元和第二中继单元。例如，后文中图17所示的第一中继光栅的最远离所述第二中继光栅的栅线与第二中继光栅的最远离所述第一中继光栅的栅线所限定的区域。In a possible implementation of the above-mentioned first aspect, the first relay unit and the second relay unit are gratings, and the first side of the relay area is the farthest side from the first relay unit. The grid line of the second relay unit, the second side is the grid line of the second relay unit farthest from the first relay unit. That is, the relay area is defined by the farthest gate line between the first relay unit and the second relay unit, including not only the area between the first relay unit and the second relay unit, but also the first relay unit and the second relay unit. Second relay unit. For example, the area defined by the grid lines of the first relay grating farthest from the second relay grating and the grid lines of the second relay grating farthest from the first relay grating shown in FIG. .

在上述第一方面的一种可能的实现中，所述第一中继单元和第二中继单元均包括多条光栅栅线，并且所述第一中继单元和第二中继单元的光栅栅线相互呈所述第一角度。In a possible implementation of the first aspect above, each of the first relay unit and the second relay unit includes a plurality of grating lines, and the gratings of the first relay unit and the second relay unit The grid lines form the first angle with each other.

在上述第一方面的一种可能的实现中，所述第一中继单元和第二中继单元均包括多条光栅栅线，并且所述第一中继单元和第二中继单元的光栅栅线相互平行。In a possible implementation of the first aspect above, each of the first relay unit and the second relay unit includes a plurality of grating lines, and the gratings of the first relay unit and the second relay unit The grid lines are parallel to each other.

即第一中继单元和第二中继单元可以均为光栅，所述第一中继单元可以包括多条平行的光栅栅线，第二中继单元可以包括多条平行的光栅栅线。第一中继单元的光栅栅线可以和第二中继单元的光栅栅线具有0°～5°的夹角。在一些实施例中，可以将第一中继单元的光栅栅线和第二中继单元的光栅栅线设置为相互平行。可以理解，如前所述，此处的平行可以是有一定误差的，即并非完全平行，而是呈一定的小角度，例如，两者的夹角在0°～5°之间。That is, both the first relay unit and the second relay unit may be gratings, the first relay unit may include multiple parallel grating lines, and the second relay unit may include multiple parallel grating lines. The grating lines of the first relay unit may have an included angle of 0°˜5° with the grating lines of the second relay unit. In some embodiments, the grating lines of the first relay unit and the grating lines of the second relay unit may be arranged parallel to each other. It can be understood that, as mentioned above, the parallel here may have certain errors, that is, it is not completely parallel, but forms a certain small angle, for example, the angle between the two is between 0° and 5°.

具体地，例如，若第一中继单元和第二中继单元为表面浮雕光栅，则栅线可以指表面浮雕光栅的刻痕，栅线平行可以指表面浮雕光栅的刻痕方向平行；若第一中继单元和第二中继单元为体全息光栅，则栅线可以指体全息光栅的条纹，栅线平行可以指体全息光栅的条纹延伸方向平行。Specifically, for example, if the first relay unit and the second relay unit are surface relief gratings, then the grid line may refer to the grooves of the surface relief grating, and parallel grid lines may mean that the direction of the grooves of the surface relief grating is parallel; When the first relay unit and the second relay unit are volume holographic gratings, the grating lines may refer to the stripes of the volume holographic grating, and the paralleling of the grating lines may refer to the parallel extending directions of the stripes of the volume holographic grating.

此外，可实施的，光栅的栅线方向为与光栅的光栅矢量方向垂直的方向，因此，第一中继单元和第二中继单元的栅线平行与也可以指表面浮雕的光栅矢量方向一致或平行。In addition, it can be implemented that the grating line direction of the grating is a direction perpendicular to the grating vector direction of the grating, therefore, the parallel grating lines of the first relay unit and the second relay unit are consistent with the grating vector direction of the surface relief or parallel.

在上述第一方面的一种可能的实现中，所述第一中继单元和第二中继单元为相互平行的条形光栅。In a possible implementation of the above first aspect, the first relay unit and the second relay unit are bar gratings parallel to each other.

在上述第一方面的一种可能的实现中，所述第一中继单元与所述第二中继单元的光栅周期相同。In a possible implementation of the foregoing first aspect, the grating periods of the first relay unit and the second relay unit are the same.

可以理解，设置第一中继单元的周期及光栅矢量方向与第二中继单元的周期及光栅矢量方向相一致，可以使得耦出单元耦出的光线的k空间区域与微型显示装置发射出的入射光的k空间区域完全重合，从而有效防止图像畸变的产生。It can be understood that setting the period and the direction of the grating vector of the first relay unit to be consistent with the period and direction of the grating vector of the second relay unit can make the k-space area of the light coupled out by the outcoupling unit consistent with the light emitted by the micro display device. The k-space regions of the incident light overlap completely, thus effectively preventing image distortion.

在上述第一方面的一种可能的实现中，所述第一中继单元的衍射效率均匀分布，所述第二中继单元的衍射效率由远离所述耦出单元的一侧至靠近所述耦出单元的一侧逐渐降低。In a possible implementation of the first aspect above, the diffraction efficiency of the first relay unit is evenly distributed, and the diffraction efficiency of the second relay unit is from the side far away from the outcoupling unit to the side close to the One side of the outcoupling unit is gradually lowered.

可以理解，将所述第二中继单元的衍射效率设置为由远离所述耦出单元的一侧至靠近所述耦出单元的一侧逐渐降低，可以使得所述波导衬底中进行全反射传播的光线在入射到所述第二中继单元后至少部分出射光线朝着所述第一中继单元进行全反射传播，至少部分出射光线朝着所述耦出单元进行全反射传播。It can be understood that setting the diffraction efficiency of the second relay unit to gradually decrease from the side away from the outcoupling unit to the side close to the outcoupling unit can make total reflection in the waveguide substrate After the propagating light is incident on the second relay unit, at least part of the outgoing light is propagated toward the first relay unit through total reflection, and at least part of the outgoing light is propagated toward the outcoupling unit through total reflection.

同时，将所述第一中继单元的衍射效率设置为均等分布，可以使得所述波导衬底中全反射传播的光线在入射到所述第一中继单元后改变全反射传播的方向，朝着所述第二中继单元进行全反射传播。At the same time, setting the diffraction efficiency of the first relay unit to be uniformly distributed can make the light propagating through total reflection in the waveguide substrate change the direction of total reflection propagation after being incident on the first relay unit, toward performing total reflection propagation along the second relay unit.

在上述第一方面的一种可能的实现中，所述第一中继单元为表面浮雕光栅，并且所述第一中继单元的光栅高度均等分布。In a possible implementation of the above first aspect, the first relay unit is a surface relief grating, and grating heights of the first relay unit are evenly distributed.

可以理解，设置所述第一中继单元的光栅高度均等分布可以使得所述第一中继单元的衍射效率均等分布。It can be understood that setting the grating heights of the first relay units to be evenly distributed can make the diffraction efficiency of the first relay units evenly distributed.

在上述第一方面的一种可能的实现中，所述第二中继单元为表面浮雕光栅，并且所述第二中继单元的光栅高度由远离所述耦出单元的一侧至靠近所述耦出单元的一侧逐渐降低。In a possible implementation of the first aspect above, the second relay unit is a surface relief grating, and the height of the grating of the second relay unit is from a side far away from the outcoupling unit to a side close to the One side of the outcoupling unit is gradually lowered.

可以理解，设置第二中继单元的光栅高度由远离所述耦出单元的一侧至靠近所述耦出单元的一侧逐渐降低可以使得所述第二中继单元的衍射效率由远离所述耦出单元的一侧至靠近所述耦出单元的一侧逐渐降低。It can be understood that setting the grating height of the second relay unit to gradually decrease from the side away from the outcoupling unit to the side close to the outcoupling unit can make the diffraction efficiency of the second relay unit decrease from the side farther away from the outcoupling unit. The side of the outcoupling unit is gradually lowered to the side close to the outcoupling unit.

在上述第一方面的一种可能的实现中，所述第一中继单元为体全息光栅，并且所述第一中继单元的折射率调制度均等分布。In a possible implementation of the above first aspect, the first relay unit is a volume holographic grating, and the refractive index modulation degrees of the first relay unit are equally distributed.

可以理解，设置所述第一中继单元的折射率调制度均等分布可以使得所述第一中继单元的衍射效率均等分布。It can be understood that setting the refractive index modulation degree of the first relay unit to be uniformly distributed may make the diffraction efficiency of the first relay unit uniformly distributed.

在上述第一方面的一种可能的实现中，所述第二中继单元为体全息光栅，并且所述第二中继单元的光栅折射率调制度由远离所述耦出单元的一侧至靠近所述耦出单元的一侧逐渐降低。In a possible implementation of the first aspect above, the second relay unit is a volume holographic grating, and the grating refractive index modulation degree of the second relay unit is from the side away from the outcoupling unit to The side close to the outcoupling unit is gradually lowered.

可以理解，设置所述第二中继单元的光栅折射率调制度由远离所述耦出单元的一侧至靠近所述耦出单元的一侧逐渐降低可以使得所述第二中继单元的衍射效率由远离所述耦出单元的一侧至靠近所述耦出单元的一侧逐渐降低。It can be understood that setting the grating refractive index modulation degree of the second relay unit to gradually decrease from the side away from the outcoupling unit to the side close to the outcoupling unit can make the diffraction of the second relay unit The efficiency gradually decreases from a side away from the outcoupling unit to a side close to the outcoupling unit.

在上述第一方面的一种可能的实现中，还包括设置于所述波导衬底上的至少一个第三中继单元，所述第三中继单元设位于所述第一中继单元与所述第二中继单元之间，并且所述第三中继单元将所述中继区域划分为多个中继子区域，并且所述中继子区域的两条长边在延伸方向的夹角小于所述第一角度。In a possible implementation of the first aspect above, it further includes at least one third relay unit disposed on the waveguide substrate, and the third relay unit is disposed between the first relay unit and the Between the second relay units, and the third relay unit divides the relay area into a plurality of relay sub-areas, and the angle between the two long sides of the relay sub-areas in the extending direction is smaller than the specified Describe the first angle.

即在本申请实施例中，中继单元可以有多个，第三中继单元可以将第一中继单元和第二中继单元限定的中继区域划分为多个中继子区域。例如，第一中继单元和第二中继单元之间加入一个第三中继单元后，将中继区域划分为两个中继子区域。例如，在后文中，第一中继单元可以是后文中的第一中继光栅，第二中继单元可以是后文中的第二中继光栅，第三中继单元可以为后文中提及的第三中继光栅，加入一个第三中继光栅将中继区域划分为两个中继子区域。That is, in this embodiment of the present application, there may be multiple relay units, and the third relay unit may divide the relay area defined by the first relay unit and the second relay unit into multiple relay sub-areas. For example, after adding a third relay unit between the first relay unit and the second relay unit, the relay area is divided into two relay sub-areas. For example, in the hereinafter, the first relay unit may be the first relay grating hereinafter, the second relay unit may be the second relay grating hereinafter, and the third relay unit may be the hereinafter mentioned A third relay grating, adding a third relay grating to divide the relay area into two relay sub-areas.

在上述第一方面的一种可能的实现中，所述第三中继单元被配置为：使得所述波导衬底中进行全反射传播的光线入射到所述第三中继单元后，至少部分出射光线朝着所述第一中继单元进行全反射传播，至少部分出射光线朝着所述第二中继单元进行全反射传播。In a possible implementation of the above-mentioned first aspect, the third relay unit is configured such that after the light propagated through total reflection in the waveguide substrate is incident on the third relay unit, at least part of the The outgoing light propagates toward the first relay unit through total reflection, and at least part of the outgoing light propagates toward the second relay unit through total reflection.

例如，在后文中，以第一中继单元可以是第一中继光栅，第二中继单元可以是第二中继光栅，第三中继单元可以是第三中继光栅为例，则所述第三中继单元可以被配置为使得所述波导衬底中全反射传播的光线在入射到所述第三中继单元后至少部分出射光线如图26中B4箭头方向所示，朝着所述第一中继单元进行全反射传播，至少部分出射光线如图26中B5箭头方向所示，朝着所述第二中继单元进行全反射传播。For example, in the following, as an example, the first relay unit may be the first relay grating, the second relay unit may be the second relay grating, and the third relay unit may be the third relay grating, then the The third relay unit may be configured such that at least part of the light rays transmitted by total reflection in the waveguide substrate are incident on the third relay unit, as shown in the direction of the arrow B4 in FIG. 26 , toward the The first relay unit performs total reflection propagation, and at least part of the outgoing light rays propagate toward the second relay unit as shown in the direction of the arrow B5 in FIG. 26 through total reflection.

在上述第一方面的一种可能的实现中，所述第一中继单元、第二中继单元、以及所述第三中继单元为光栅。In a possible implementation of the foregoing first aspect, the first relay unit, the second relay unit, and the third relay unit are gratings.

例如，第一中继单元可以是后文中的第一中继光栅，第二中继单元可以是后文中的第二中继光栅，第三中继单元可以为后文中提及的第三中继光栅。For example, the first relay unit may be the first relay grating hereinafter, the second relay unit may be the second relay grating hereinafter, and the third relay unit may be the third relay grating hereinafter raster.

在上述第一方面的一种可能的实现中，所述第一中继单元、第二中继单元、以及所述第三中继单元均包括多条相互平行的栅线。In a possible implementation of the foregoing first aspect, each of the first relay unit, the second relay unit, and the third relay unit includes a plurality of gate lines parallel to each other.

在上述第一方面的一种可能的实现中，所述第三中继单元为条形光栅。In a possible implementation of the above first aspect, the third relay unit is a bar grating.

在上述第一方面的一种可能的实现中，所述第三中继单元的衍射效率由靠近所述第一中继单元的一侧至靠近所述第二中继单元的一侧逐渐降低。In a possible implementation of the above first aspect, the diffraction efficiency of the third relay unit gradually decreases from a side close to the first relay unit to a side close to the second relay unit.

可以理解，设置第三中继单元的衍射效率由靠近所述第一中继单元的一侧至靠近所述第二中继单元的一侧逐渐降低可以使得所述波导衬底中进行全反射传播的光线入射到所述第三中继单元后，至少部分出射光线朝着所述第一中继单元进行全反射传播，至少部分出射光线朝着所述第二中继单元进行全反射传播。It can be understood that setting the diffraction efficiency of the third relay unit to gradually decrease from the side close to the first relay unit to the side close to the second relay unit can make total reflection propagation in the waveguide substrate After the light rays are incident on the third relay unit, at least part of the outgoing light rays propagate toward the first relay unit through total reflection, and at least part of the outgoing light rays propagate toward the second relay unit through total reflection.

在上述第一方面的一种可能的实现中，所述第三中继单元为表面浮雕光栅，并且所述第三中继单元的光栅高度由靠近所述第一中继单元的一侧至靠近所述第二中继单元的一侧逐渐降低。In a possible implementation of the above-mentioned first aspect, the third relay unit is a surface relief grating, and the height of the grating of the third relay unit is from a side close to the first relay unit to a side close to the first relay unit. One side of the second relay unit is gradually lowered.

可以理解，设置第三中继单元的光栅高度由靠近所述第一中继单元的一侧至靠近所述第二中继单元的一侧逐渐降低可以使得第三中继单元的衍射效率由靠近所述第一中继单元的一侧至靠近所述第二中继单元的一侧逐渐降低。It can be understood that setting the grating height of the third relay unit to gradually decrease from the side close to the first relay unit to the side close to the second relay unit can make the diffraction efficiency of the third relay unit decrease from close to A side of the first relay unit is gradually lowered to a side close to the second relay unit.

在上述第一方面的一种可能的实现中，所述第三中继单元为体全息光栅，并且所述第三中继单元的光栅折射率调制度由靠近所述第一中继单元的一侧至靠近所述第二中继单元的一侧逐渐降低。In a possible implementation of the above first aspect, the third relay unit is a volume holographic grating, and the grating refractive index modulation degree of the third relay unit is controlled by a gradually decrease from the side to the side close to the second relay unit.

可以理解，设置第三中继单元的光栅折射率调制度由靠近所述第一中继单元的一侧至靠近所述第二中继单元的一侧逐渐降低可以使得第三中继单元的衍射效率由靠近所述第一中继单元的一侧至靠近所述第二中继单元的一侧逐渐降低。It can be understood that setting the grating refractive index modulation degree of the third relay unit to gradually decrease from the side close to the first relay unit to the side close to the second relay unit can make the diffraction of the third relay unit The efficiency gradually decreases from a side close to the first relay unit to a side close to the second relay unit.

在上述第一方面的一种可能的实现中，所述耦入单元位于所述中继区域中。In a possible implementation of the foregoing first aspect, the coupling unit is located in the relay area.

可以理解，耦入单元可以位于第一中继单元和第二中继单元之间，也可以位于其他能够使得光线射至耦入单元后能够被耦入单元引导至朝向第二中继单元的方向进行传播的位置。It can be understood that the coupling unit can be located between the first relay unit and the second relay unit, or can be located in another direction so that the light can be directed toward the second relay unit by the coupling unit after it hits the coupling unit. The location where the propagation takes place.

在上述第一方面的一种可能的实现中，所述耦入单元和耦出单元为光栅，并且所述耦入单元与所述耦出单元的周期和光栅矢量方向均相同。In a possible implementation of the above first aspect, the coupling-in unit and the coupling-out unit are gratings, and the period and the grating vector direction of the coupling-in unit and the coupling-out unit are the same.

可以理解，耦入单元可以为后文中的耦入光栅，耦出单元可以为后文中的耦出光栅。本申请实施例中，设置耦入单元与所述耦出单元的周期和光栅矢量方向均相同，可以使得耦出单元耦出的光线的k空间区域与微型显示装置发射出的入射光的k空间区域完全重合，从而有效防止图像畸变的产生。It can be understood that the coupling unit may be the coupling-in grating hereinafter, and the coupling-out unit may be the coupling-out grating hereinafter. In the embodiment of the present application, setting the period and grating vector direction of the in-coupling unit and the out-coupling unit to be the same can make the k-space area of the light coupled out by the out-coupling unit and the k-space area of the incident light emitted by the micro display device The areas are completely overlapped, thus effectively preventing image distortion.

在上述第一方面的一种可能的实现中，所述耦入单元为表面浮雕光栅或者体全息光栅；并且In a possible implementation of the first aspect above, the coupling unit is a surface relief grating or a volume holographic grating; and

所述耦出单元为表面浮雕光栅或者体全息光栅。The outcoupling unit is a surface relief grating or a volume holographic grating.

在上述第一方面的一种可能的实现中，所述耦入单元、第一中继单元、第二中继单元、以及耦出单元位于所述波导衬底的至少一个底面上。In a possible implementation of the foregoing first aspect, the coupling-in unit, the first relay unit, the second relay unit, and the out-coupling unit are located on at least one bottom surface of the waveguide substrate.

可以理解，耦入单元、第一中继单元、第二中继单元、以及耦出单元可以位于波导衬底的同一底面上，与可以位于相对两个底面上，例如，耦入单元、第一中继单元、第二中继单元位于上底面，耦出单元可以位于下底面上。It can be understood that the coupling-in unit, the first relay unit, the second relay unit, and the coupling-out unit may be located on the same bottom surface of the waveguide substrate, and may be located on two opposite bottom surfaces, for example, the coupling unit, the first The relay unit and the second relay unit are located on the upper bottom surface, and the outcoupling unit may be located on the lower bottom surface.

在上述第一方面的一种可能的实现中，还包括全息材料层，并且所述波导衬底的数量为两个，所述全息材料层夹于两个所述波导衬底之间；In a possible implementation of the first aspect above, a holographic material layer is further included, and the number of the waveguide substrates is two, and the holographic material layer is sandwiched between the two waveguide substrates;

所述耦入单元、第一中继单元、第二中继单元、以及耦出单元位于所述全息材料层的至少一个底面上。The incoupling unit, the first relay unit, the second relay unit, and the outcoupling unit are located on at least one bottom surface of the holographic material layer.

可以理解，所述耦入单元、第一中继单元、第二中继单元、以及耦出单元可以为对全息材料层进行曝光形成的耦入光栅、第一中继光栅、第二中继光栅、以及耦出光栅。It can be understood that the incoupling unit, the first relay unit, the second relay unit, and the outcoupling unit may be an incoupling grating, a first relay grating, and a second relay grating formed by exposing the holographic material layer. , and outcoupling gratings.

第二方面，本申请实施例提供了一种电子设备，包括微型显示装置和上述光学设备，并且所述微型显示装置用于向所述光学设备的耦入单元投射光线。In a second aspect, an embodiment of the present application provides an electronic device, including a micro display device and the above-mentioned optical device, and the micro display device is configured to project light to an in-coupling unit of the optical device.

可以理解，光学设备可以为后文实施例中提及的衍射光波导。It can be understood that the optical device may be the diffractive optical waveguide mentioned in the following embodiments.

在上述第二方面的一种可能的实现中，所述电子设备为增强现实眼镜。In a possible implementation of the foregoing second aspect, the electronic device is augmented reality glasses.

可以理解，增强现实眼镜的镜片的部分或或全部可以采用上述光学设备，微型现实装置可以设于增强现实眼镜的镜片框架上。It can be understood that part or all of the lenses of the augmented reality glasses may use the above-mentioned optical device, and the miniature reality device may be arranged on the lens frame of the augmented reality glasses.

在上述第二方面的一种可能的实现中，所述电子设备为车载平视显示器。In a possible implementation of the foregoing second aspect, the electronic device is a vehicle-mounted head-up display.

附图说明Description of drawings

图1根据本申请的一些实施例，示出了一种透射式衍射光栅的结构示意图；Fig. 1 shows a schematic structural diagram of a transmission diffraction grating according to some embodiments of the present application;

图2根据本申请的一些实施例，示出了一种衍射光栅的分光示意图；Fig. 2 shows a schematic diagram of the spectrum of a diffraction grating according to some embodiments of the present application;

图3中(a)-(c)根据本申请的一些实施例，示出了不同形状的衍射光栅的示意图；(a)-(c) in FIG. 3 shows schematic diagrams of diffraction gratings of different shapes according to some embodiments of the present application;

图4根据本申请的一些实施例，示出了全反射原理示意图；Fig. 4 shows a schematic diagram of the principle of total reflection according to some embodiments of the present application;

图5根据本申请的一些实施例，示出了一种平面光波导的结构示意图；Fig. 5 shows a schematic structural diagram of a planar optical waveguide according to some embodiments of the present application;

图6根据本申请的一些实施例，示出了图5中平面光波导的光路图；Fig. 6 shows an optical path diagram of the planar optical waveguide in Fig. 5 according to some embodiments of the present application;

图7根据本申请的一些实施例，示出了一种用于AR眼镜的衍射光波导的结构示意图；Fig. 7 shows a schematic structural diagram of a diffractive optical waveguide for AR glasses according to some embodiments of the present application;

图8中(a)根据本申请的一些实施例，示出了一种光线在衍射光波导100中传播的导向示意图；(a) in FIG. 8 shows a schematic diagram of guiding light propagating in the diffractive optical waveguide 100 according to some embodiments of the present application;

图8中(b)和(c)根据本申请的一些实施例，示出了光线在波导衬底中传播的具体光路图；(b) and (c) in FIG. 8 show specific optical path diagrams of light propagating in a waveguide substrate according to some embodiments of the present application;

图9根据本申请的一些实施例，示出了一种采用衍射光波导作为镜片的AR眼镜的结构示意图；Fig. 9 shows a schematic structural diagram of AR glasses using a diffractive optical waveguide as a lens according to some embodiments of the present application;

图10根据本申请的一些实施例，示出了一种虚拟图像通过AR眼镜的左镜片或右镜片耦入人眼的原理示意图；Fig. 10 shows a schematic diagram of the principle of coupling a virtual image into human eyes through the left or right lens of AR glasses according to some embodiments of the present application;

图11根据本申请的一些实施例，示出了一种衍射光波导的结构示意图。Fig. 11 shows a schematic structural diagram of a diffractive optical waveguide according to some embodiments of the present application.

图12中(a)和(b)根据本申请的一些实施例，分别示出了在不同视场角下光线在衍射光波导中的导向示意图；(a) and (b) in FIG. 12 respectively show schematic diagrams of guiding light in a diffractive optical waveguide at different viewing angles according to some embodiments of the present application;

图13中(a)和(b)根据本申请的一些实施例，分别示出了光线在中继光栅和耦出光栅处的衍射光路图；(a) and (b) in FIG. 13 respectively show the diffraction light path diagrams of the light at the relay grating and the outcoupling grating according to some embodiments of the present application;

图14根据本申请的一些实施例，示出了一种采用衍射光波导作为镜片的AR眼镜的结构示意图；Fig. 14 shows a schematic structural diagram of AR glasses using a diffractive optical waveguide as a lens according to some embodiments of the present application;

图15根据本申请的一些实施例，示出了一种视场角的示意图；Fig. 15 shows a schematic diagram of a field of view according to some embodiments of the present application;

图16中(a)和(b)根据本申请的一些实施例，分别示出了较小边缘视场夹角A1和较大边缘视场夹角A2的图像在图11中所示的衍射光波导结构中传播的导向对比示意图；(a) and (b) in Fig. 16, according to some embodiments of the present application, respectively show the diffracted light shown in Fig. 11 for the images of the smaller marginal field of view angle A1 and the larger peripheral field of view angle A2 Schematic diagram of the guide comparison of propagation in the waveguide structure;

图17根据本申请的一些实施例，示出了一种包括两个中继光栅的衍射光波导的示意图。Fig. 17 shows a schematic diagram of a diffractive optical waveguide including two relay gratings according to some embodiments of the present application.

图18中(a)和(b)根据本申请的一些实施例，分别示出了本申请实施例光线在波导衬底中传播的不同角度的导向的示意图；(a) and (b) in FIG. 18 respectively show schematic diagrams of different angles of light propagating in the waveguide substrate according to some embodiments of the present application;

图19中(a)根据本申请的一些实施例，示出了光线在第一中继光栅和第二中继光栅处的衍射光路图；(a) in Fig. 19 shows the diffraction light path diagram of light at the first relay grating and the second relay grating according to some embodiments of the present application;

图19中(b)根据本申请的一些实施例，示出了光线在耦出光栅处的衍射光路图；(b) in FIG. 19 shows the diffraction light path diagram of the light at the outcoupling grating according to some embodiments of the present application;

图20中(a)和(b)根据本申请的一些实施例，分别示出了较小边缘视场夹角A1和较大边缘视场夹角A2的图像在图17所示的衍射光波导中传播的导向对比示意图。(a) and (b) in Fig. 20, according to some embodiments of the present application, respectively show the images of the smaller edge field angle A1 and the larger edge field angle A2 in the diffractive optical waveguide shown in Fig. 17 Schematic diagram of the orientation comparison of propagation in China.

图21根据本申请的一些实施例，示出了一种第二中继光栅的示意图；Fig. 21 shows a schematic diagram of a second relay grating according to some embodiments of the present application;

图22根据本申请的一些实施例，示出了一种耦入光栅的位置示意图；Fig. 22 shows a schematic diagram of the position of a coupling-in grating according to some embodiments of the present application;

图23根据本申请的一些实施例，示出了一种耦入光栅的位置示意图；Fig. 23 shows a schematic diagram of the position of a coupling-in grating according to some embodiments of the present application;

图24根据本申请的一些实施例，示出了一种采用图17所示的衍射光波导作为镜片的AR眼镜的结构示意图；Fig. 24 shows a schematic structural view of AR glasses using the diffractive optical waveguide shown in Fig. 17 as a lens according to some embodiments of the present application;

图25根据本申请的一些实施例，示出了一种衍射光波导的结构结构示意图；Fig. 25 shows a schematic structural diagram of a diffractive optical waveguide according to some embodiments of the present application;

图26根据本申请的一些实施例，示出了光线在三个中继光栅的衍射光波导中的导向示意图；Fig. 26 shows a schematic diagram of guiding light in diffractive optical waveguides of three relay gratings according to some embodiments of the present application;

图27根据本申请的一些实施例，示出了一种衍射光波导的的示意图；Fig. 27 shows a schematic diagram of a diffractive optical waveguide according to some embodiments of the present application;

图28根据本申请的一些实施例，示出了一种衍射光波导的的示意图；Fig. 28 shows a schematic diagram of a diffractive optical waveguide according to some embodiments of the present application;

图29根据本申请的一些实施例，示出了图17所示的衍射光波导的k空间路径示意图。Fig. 29 shows a schematic diagram of the k-space path of the diffractive optical waveguide shown in Fig. 17 according to some embodiments of the present application.

附图标记说明：Explanation of reference signs:

100-衍射光波导；101-耦入光栅；102-中继光栅；1021-第一中继光栅；1022-第二中继光栅；1023-第三中继光栅；103-耦出光栅；104-波导衬底；105-微型显示装置；106-光源；107-波导顶层；108-全息材料层；100-diffraction optical waveguide; 101-coupling grating; 102-relay grating; 1021-first relay grating; 1022-second relay grating; 1023-third relay grating; 103-coupling grating; 104- waveguide substrate; 105-micro display device; 106-light source; 107-waveguide top layer; 108-holographic material layer;

200-AR眼镜；201-左镜腿；202-右镜腿；203-镜片框架203，204-左镜片；205-右镜片；200-AR glasses; 201-left temple; 202-right temple; 203-lens frame 203, 204-left lens; 205-right lens;

300-衍射光栅；301-狭缝；302-刻痕；303-玻璃基片；304-介质膜。300-diffraction grating; 301-slit; 302-notch; 303-glass substrate; 304-dielectric film.

具体实施方式detailed description

以下由特定的具体实施例说明本申请的实施方式，本领域技术人员可由本说明书所揭示的内容轻易地了解本申请的其他优点及功效。The implementation of the present application will be described by specific specific examples below, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification.

为了便于理解本申请的技术方案，现将本申请中涉及到的一些技术术语、光学原件以及相关原理进行介绍。In order to facilitate the understanding of the technical solution of this application, some technical terms, optical elements and related principles involved in this application are now introduced.

(一)光的衍射：光在传播路径中，遇到不透明或透明的障碍物或者小孔(窄缝)，绕过障碍物，产生偏离直线传播的现象称为光的衍射。(1) Diffraction of light: In the propagation path, light encounters opaque or transparent obstacles or small holes (narrow slits), bypasses obstacles, and produces a phenomenon that deviates from straight-line propagation, which is called light diffraction.

(二)光栅：是由大量等宽等间距的平行狭缝构成的光学器，也可称为衍射光栅，能够将照射到衍射光栅上的光线通过衍射光栅的衍射改变传播方向。其中，衍射光栅可以包括利用透射光衍射的光栅，称为透射式衍射光栅；还有利用两刻痕间的反射光进行衍射的光栅，称为反射式衍射光栅。(2) Grating: An optical device composed of a large number of parallel slits of equal width and equal spacing, also known as a diffraction grating, which can change the propagation direction of light irradiated on the diffraction grating through the diffraction of the diffraction grating. Among them, the diffraction grating may include a grating that uses transmitted light to diffract, called a transmission diffraction grating; and a grating that uses reflected light between two notches to diffract, called a reflective diffraction grating.

例如，图1示出了一种透射式衍射光栅300的结构示意图。如图1中所示，衍射光栅300可以由玻璃上刻蚀出的多个狭缝301和刻痕302形成，其中，狭缝301为透光部分，刻痕302为不透光部分。衍射光栅300的光学特性与衍射光栅的周期相关，衍射光栅的周期为单个狭缝301和单个刻痕302的宽度的和，例如，若狭缝301的宽度为a,刻痕302的宽度为b.则衍射光栅300的周期d为狭缝301的宽度a与刻痕302的宽度b的和，即d＝a+b；其中，光栅周期越小，则在单位长度内狭缝301的数量越多，单个狭缝301的宽度越窄。For example, FIG. 1 shows a schematic structural diagram of a transmissive diffraction grating 300 . As shown in FIG. 1 , the diffraction grating 300 can be formed by a plurality of slits 301 and notches 302 etched on glass, wherein the slits 301 are light-transmitting parts, and the notches 302 are light-impermeable parts. The optical characteristics of the diffraction grating 300 are related to the period of the diffraction grating. The period of the diffraction grating is the sum of the widths of a single slit 301 and a single notch 302. For example, if the width of the slit 301 is a, the width of the notch 302 is b. Then the period d of the diffraction grating 300 is the sum of the width a of the slit 301 and the width b of the notch 302, that is, d=a+b; wherein, the smaller the period of the grating, the more the number of slits 301 per unit length , the narrower the width of a single slit 301 is.

可实施的，衍射光栅300也可以由全息技术在材料内部曝光形成全息光栅，即通过全息照相，将激光产生的干涉条纹在干板上曝光，经显影定影形成全息光栅。In practice, the diffraction grating 300 can also be exposed inside the material by holographic technology to form a holographic grating, that is, through holography, the interference fringes generated by the laser are exposed on a dry plate, and then developed and fixed to form a holographic grating.

衍射光栅300具有分光特性，例如，用于本申请的AR眼镜的衍射光波导就是利用这种分光特性来实现对光线传播方向的引导，下文将进行详细描述。The diffraction grating 300 has spectroscopic characteristics. For example, the diffractive optical waveguide used in the AR glasses of the present application utilizes such spectroscopic characteristics to guide the light propagation direction, which will be described in detail below.

具体的，如图2所示，当入射光线i入射到光栅高度为h,周期为d的衍射光栅300时，它会被衍射光栅300分成若干个衍射级(diffraction order)，每一个衍射级沿着不同的方向继续传播下去，包括反射式衍射,例如,0级反射衍射R0,一级反射衍射R1,负一级反射衍射R-1等,以及透射式衍射,例如,0级透射衍射T0,一级透射衍射T1,负一级透射衍射T-1等。Specifically, as shown in FIG. 2, when the incident ray i is incident on the diffraction grating 300 with a grating height of h and a period of d, it will be divided into several diffraction orders by the diffraction grating 300, and each diffraction order is along the Continue to propagate in different directions, including reflection diffraction, for example, 0-order reflection diffraction R0, first-order reflection diffraction R1, negative first-order reflection diffraction R-1, etc., and transmission diffraction, for example, 0-order transmission diffraction T0, First-order transmission diffraction T1, negative first-order transmission diffraction T-1, etc.

为了使入射光线i通过衍射光栅300的光线能够发生m级次的衍射，则衍射光栅的参数需要满足下述公式(1)：In order to make the incident ray i pass through the diffraction grating 300 to undergo m-order diffraction, the parameters of the diffraction grating need to satisfy the following formula (1):

其中，d为衍射光栅的周期，m为衍射级次，m为整数，例如可以为0，1，-1，2，-2等；n为玻璃3的折射率；θ _m及

分别为m级次所对应的衍射光的极角及方位角；λ为入射光线i的波长，θ及

分别为入射光线i的极角及方位角；θ _Gin为衍射光栅的刻痕302的角度。: Wherein, d is the period of the diffraction grating, m is the diffraction order, and m is an integer, such as 0, 1, -1, 2, -2, etc.; n is the refractive index of the glass 3; θ _m and

are the polar angle and azimuth angle of the diffracted light corresponding to the m order; λ is the wavelength of the incident light i, θ and

are the polar angle and the azimuth angle of the incident ray i; θ _Gin is the angle of the notch 302 of the diffraction grating. :

上式(1)表明，当入射光线i的波长λ、入射光线i的极角θ及方位角

一定时，通过调控衍射光栅的刻痕302的角度θ _Gin、衍射光栅的周期d可以对衍射光的衍射极次，极角θ _m及方位角

进行调整。 The above formula (1) shows that when the wavelength λ of the incident ray i, the polar angle θ and the azimuth angle of the incident ray i

At a certain time, by adjusting the angle θ _Gin of the notch 302 of the diffraction grating and the period d of the diffraction grating, the extreme order of diffraction of the diffracted light, the polar angle θ _m and the azimuth angle

Make adjustments.

例如，在AR眼镜采用的衍射光波导中，可以通过调控波导衬底表面的各衍射光栅的刻痕302的角度θ _Gin、衍射光栅的周期d，对衍射光的衍射极次m、极角θ _m及方位角

进行调整，使得在衍射光波导的波导衬底中全反射传播的光线可以在入射到波导衬底表面上的衍射光栅之后，沿着需要的方向传播。 For example, in the diffractive optical waveguide used in AR glasses, the angle θ _Gin of the notch 302 of each diffraction grating on the surface of the waveguide substrate and the period d of the diffraction grating can be controlled to control the diffraction order m and polar angle θ of the diffracted light. _m and azimuth

Adjustment is made so that the light propagating through total reflection in the waveguide substrate of the diffractive optical waveguide can propagate along a desired direction after being incident on the diffraction grating on the surface of the waveguide substrate.

衍射光栅的形状可以根据实际需求设计为多种，例如，图3中(a)-(c)示出了不同形状的衍射光栅的示意图，其中，如图3中(a)所示，衍射光栅可以为,均匀垂直光栅，如图3中(b)中所示，衍射光栅也可以倾斜光栅，如图3中(c)所示,衍射光栅还可以为高度不均匀的光栅。The shape of the diffraction grating can be designed into a variety according to actual needs, for example, (a)-(c) in Fig. 3 shows the schematic diagram of the diffraction grating of different shapes, wherein, as shown in (a) among Fig. 3, the diffraction grating It can be a uniform vertical grating, as shown in (b) in Figure 3, and the diffraction grating can also be a tilted grating, as shown in Figure 3 (c), and the diffraction grating can also be a highly non-uniform grating.

(三)光的全反射(3) Total reflection of light

光的全反射又称光的全内反射，是指当光线从较高折射率的介质进入到较低折射率的介质时，如果入射角大于某一临界角C(光线远离法线)，则折射光线将会消失，所有的入射光线将被反射而不进入低折射率的介质。The total reflection of light, also known as the total internal reflection of light, means that when light enters a medium with a lower refractive index from a medium with a higher refractive index, if the incident angle is greater than a certain critical angle C (the light is far away from the normal), then Refracted rays will disappear, and all incident rays will be reflected without entering the low-index medium.

例如，如图4所示，当入射光线i从折射率为n1的介质P1射向折射率为n ₂的介质P2时，若n ₁大于n ₂，且光线的入射角C1大于临界角C，则入射光线i将被反射而不进入低折射率n ₂的介质P2。 For example, as shown in Figure 4, when the incident ray i travels from the medium P1 with the refractive index n1 to the medium P2 with the refractive index _n2 , if n1 is greater than _n2 , and the incident angle _C1 of the light is greater than the critical angle C, Then the incident ray i will be reflected and not enter the medium P2 with low refractive index _n2 .

其中，临界角C需满足的条件即光的全反射公式为：Among them, the condition that the critical angle C needs to meet, that is, the total reflection formula of light is:

sinC＝n ₂/n ₁ (2) sinC=n ₂ /n ₁ (2)

如图4中所示，当折射率为n ₂的介质P2为空气时，因n ₂＝1，则临界角C需满足的条件为：sinC＝1/n ₁。 As shown in FIG. 4 , when the medium P2 with a refractive index n ₂ is air, since n ₂ =1, the condition that the critical angle C needs to satisfy is: sinC=1/n ₁ .

(四)光波导：(4) Optical waveguide:

光波导是指利用全反射原理引导光波在其本身中传播的光学元件。常见的光波导可以为由光透明介质(如折射率较大的石英玻璃)构成的传输光频电磁波的导行结构。光波导具体的可分为平面结构和条形结构。An optical waveguide refers to an optical element that uses the principle of total reflection to guide light waves to propagate in itself. A common optical waveguide can be a guiding structure made of an optically transparent medium (such as quartz glass with a relatively high refractive index) that transmits optical frequency electromagnetic waves. Specifically, the optical waveguide can be divided into a planar structure and a strip structure.

例如，图5示出了一种平面光波导10的结构图，而图6示出了该平面光波导10的光路图。For example, FIG. 5 shows a structural diagram of a planar optical waveguide 10 , and FIG. 6 shows an optical path diagram of the planar optical waveguide 10 .

如图5所示，该平面结构光波导10可以包括玻璃基片303和位于玻璃基片303上方的介质膜304。其中，假设介质膜304的折射率为n ₁，玻璃基片303的折射率为n2，介质膜304与玻璃基底303的界面上光产生全反射的临界角为θ ₁，介质膜304与空气的界面上光产生全反射的临界角为θ ₂。 As shown in FIG. 5 , the planar structured optical waveguide 10 may include a glass substrate 303 and a dielectric film 304 on the glass substrate 303 . Wherein, assuming that the refractive index of the dielectric film 304 is n ₁ , the refractive index of the glass substrate 303 is n2, the critical angle for total reflection of light on the interface between the dielectric film 304 and the glass substrate 303 is θ ₁ , and the distance between the dielectric film 304 and the air is The critical angle for total reflection of light on the interface is θ ₂ .

入射光线i从空气中通过折射射入介质膜304与玻璃基底303的界面上，为了使射到介质膜304与玻璃基底303的界面的光线能够发生全反射，并能够在折射率为n ₁的介质膜的上下表面之间进行全反射传播，需要使得介质膜304的折射率n ₁，玻璃基片303的折射率n ₂及空气的折射率n ₃满足的关系为：n ₁＞n ₂＞n ₃。 _The incident ray i enters the interface between the dielectric film 304 and the glass substrate 303 through refraction from the air. For total reflection propagation between the upper and lower surfaces of the dielectric film, it is necessary to make the refractive index n 1 of the dielectric film 304, the refractive index n ₂ of the glass substrate 303 and the refractive index n ₃ of the air satisfy the relationship _: n ₁ >n ₂ > n ₃ .

需要使得入射光线i的入射角θ、介质膜304与玻璃基底303的界面上光产生全反射的临界角θ ₁及介质膜304与空气的界面上光产生全反射的临界角θ ₂满足的关系为：θ＞θ ₁＞θ ₂。 It is necessary to make the incident angle θ of the incident ray i, the critical angle θ ₁ of the total reflection of the light on the interface between the dielectric film 304 and the glass substrate 303, and the critical angle θ ₂ of the total reflection of the light on the interface of the dielectric film 304 and the air to satisfy the relationship It is: θ>θ ₁ >θ ₂ .

其中，θ ₁与θ ₂的计算方式如下： Among them, θ ₁ and θ ₂ are calculated as follows:

θ ₁＝arcsin(n ₂/n ₁)； θ ₁ = arcsin(n ₂ /n ₁ );

θ ₂＝arcsin(n ₃/n ₁)。 θ ₂ =arcsin(n ₃ /n ₁ ).

具体的，光线在光波导传播的光路图如图6所示，入射光线i从空气中通过折射射入介质膜304与玻璃基底303的界面上，在介质膜304与玻璃基底303的界面上发生全反射，光线被全反射到介质膜304与空气的界面上时，会继续被全反射至介质膜304与玻璃基底303的界面上。如此，光线会在介质膜304的上下表面之间进行全反射传播。Specifically, the optical path diagram of light propagating in the optical waveguide is shown in FIG. Total reflection, when the light is totally reflected on the interface between the dielectric film 304 and the air, it will continue to be totally reflected on the interface between the dielectric film 304 and the glass substrate 303 . In this way, the light propagates through total reflection between the upper and lower surfaces of the dielectric film 304 .

可以看出，光波导实质上可以为折射率较大的一个介质层，能够使得光线在其内部进行全反射传播。目前，常用的AR眼镜200的镜片为衍射光波导100，即为了将AR眼镜200中的微型显示器发出的光线能够在AR眼镜200的镜片的指定位置导入，并在镜片的指定位置导出进入人眼，通常在光波导的表面设置有前述的衍射光栅。例如，图7示出了一种用于AR眼镜200的衍射光波导100的结构示意图。It can be seen that the optical waveguide can essentially be a dielectric layer with a relatively large refractive index, which can make the light propagate inside it through total reflection. At present, the lens of the commonly used AR glasses 200 is a diffractive waveguide 100, that is, in order to guide the light emitted by the micro-display in the AR glasses 200 into the designated position of the lens of the AR glasses 200, and guide it into the human eye at the designated position of the lens. , usually the aforementioned diffraction grating is arranged on the surface of the optical waveguide. For example, FIG. 7 shows a schematic structural diagram of a diffractive optical waveguide 100 for AR glasses 200 .

如图7所示，衍射光波导100包括波导衬底104、用于将光线耦入波导衬底的耦入光栅101及用于将光线耦出波导衬底的耦出光栅103。其中波导衬底104可以由上述图6所示的平面结构光波导构成，并且可以采用高折射率玻璃材质制成，例如，折射率范围为1.5-2.2。As shown in FIG. 7 , the diffractive optical waveguide 100 includes a waveguide substrate 104 , an incoupling grating 101 for coupling light into the waveguide substrate, and an outcoupling grating 103 for coupling light out of the waveguide substrate. The waveguide substrate 104 can be composed of the above-mentioned planar structure optical waveguide shown in FIG. 6 , and can be made of high refractive index glass material, for example, the refractive index range is 1.5-2.2.

图8中(a)示出了光线在衍射光波导100中传播的导向示意图。(a) of FIG. 8 shows a schematic diagram of guiding light propagating in the diffractive optical waveguide 100 .

可以理解，在本申请各实施例中，光线的导向示意图与光路图不同，并不是光线的实际传播路径，而是对光线全反射过程中光线的整个行径方向的示意。例如，对于图6所示的全反射光路图，光线在介质膜304中的实际光路径由带有箭头的光线表示，而发生全反射光线的整个行径方向可以认为是沿x轴负半轴行径。It can be understood that in each embodiment of the present application, the schematic diagram of light guidance is different from the light path diagram, and is not the actual propagation path of the light, but a schematic representation of the entire travel direction of the light during the total reflection of the light. For example, for the total reflection light path diagram shown in FIG. 6 , the actual light path of the light in the dielectric film 304 is indicated by the light with arrows, and the entire travel direction of the total reflection light can be considered to be along the negative semi-axis of the x-axis. .

下面继续参考图8中(a)介绍衍射光波导100的光线行径方向。如图8中(a)所示，光源106发出的光线i1入射到耦入光栅101后，通过耦入光栅101的衍射耦入波导衬底104，并在波导衬底104的上下表面之间进行全反射传播。图8中(a)中箭头B1示出了在波导衬底104中发生全反射的光线的整个前进路径，即沿x轴负半轴的方向前进。而在波导衬底104中沿x轴负半轴的方向前进的全反射光线在遇到耦出光栅103后，光线中的一部分光线会被耦出波导衬底104，耦出的光线的行进方向如图8中的箭头B2所示，即z轴正半轴方向。The light traveling direction of the diffractive optical waveguide 100 will be described below with reference to (a) in FIG. 8 . As shown in (a) of FIG. 8 , after the light i1 emitted by the light source 106 is incident on the in-coupling grating 101, it is coupled into the waveguide substrate 104 through the diffraction of the in-coupling grating 101, and is transmitted between the upper and lower surfaces of the waveguide substrate 104. Total reflection propagation. The arrow B1 in (a) of FIG. 8 shows the entire advancing path of the totally reflected light in the waveguide substrate 104 , that is, advancing along the direction of the negative half-axis of the x-axis. In the waveguide substrate 104, the totally reflected light traveling in the direction of the negative semi-axis of the x-axis encounters the outcoupling grating 103, a part of the light will be outcoupled out of the waveguide substrate 104, and the traveling direction of the outcoupled light is As shown by the arrow B2 in FIG. 8 , that is, the direction of the positive semi-axis of the z-axis.

光线在波导衬底104中传播的具体光路图如图8中(b)所示，光源106发出的光线i1在入射到耦入光栅101后，通过耦入光栅101的衍射改变原传播方向而射向波导衬底104的底部。基于前述全反射原理可知，由于射向波导衬底104的底部的光线的入射角度大于波导衬底104与空气界面的全反射临界角，且波导衬底104的折射率大于空气的折射率，因此，经耦入光栅101耦入波导衬底104的光线i1能够在波导衬底104的上下表面之间全反射传播。The specific optical path diagram of the light propagating in the waveguide substrate 104 is shown in Fig. 8 (b). After the light i1 emitted by the light source 106 is incident on the in-coupling grating 101, the original propagation direction is changed by the diffraction of the in-coupling grating 101 and then emitted. to the bottom of the waveguide substrate 104 . Based on the foregoing total reflection principle, it can be known that since the incident angle of light directed at the bottom of the waveguide substrate 104 is greater than the critical angle of total reflection at the interface between the waveguide substrate 104 and the air, and the refractive index of the waveguide substrate 104 is greater than that of air, therefore , the light i1 coupled into the waveguide substrate 104 through the coupling-in grating 101 can propagate through total reflection between the upper and lower surfaces of the waveguide substrate 104 .

而光线i1在波导衬底104中全反射传播的过程中，如图8中(c)所示，当光线i1在全反射过程中，遇到波导衬底104表面的耦出光栅103的D1位置时，会有一部分光线i2通过光栅衍射释放出去，即被耦出波导衬底104，而剩下的一部分光线i3继续在波导衬底104中进行全反射传播。全反射传播的光线i3在后续传播的过程中，当入射到波导衬底104表面的耦出光栅103上的位置D2时，重复上述现象，即一部分光线i4续通过光栅衍射被耦出波导衬底104，剩下的一部分光线i5继续在波导衬底104中进行全反射传播，直至在波导衬底104全反射传播的光线全部被耦出波导衬底104。In the process of total reflection and propagation of light i1 in the waveguide substrate 104, as shown in (c) in FIG. , a part of light i2 is released through grating diffraction, that is, is coupled out of the waveguide substrate 104 , while the remaining part of light i3 continues to propagate in the waveguide substrate 104 through total reflection. During the subsequent propagation, the light i3 propagating through total reflection is incident on the position D2 on the outcoupling grating 103 on the surface of the waveguide substrate 104, the above phenomenon is repeated, that is, a part of the light i4 is coupled out of the waveguide substrate through grating diffraction 104 , the remaining part of the light i5 continues to propagate through the total reflection in the waveguide substrate 104 until all the light rays propagating through the total reflection on the waveguide substrate 104 are coupled out of the waveguide substrate 104 .

基于上面的描述可知，对于图6至图8中所示的衍射光波导100，在光线在波导衬底104内全反射传播的过程中，同一束光每次遇到波导衬底104表面的耦出光栅103的某一位置时，有一部分光线通过衍射释放出波导衬底104的同时，另一部分光线继续在波导中全反射传播，并在耦出光栅103的不同位置重复上述现象，从而将光源106入射的光线沿x轴正半轴方向复制多份，这样通过耦出光栅103耦出的光线也会在x轴负半轴方向上被放大。该现象可以被称为出瞳扩展，对于图6至图8中所示的衍射光波导100，当将其用作AR眼镜的镜片时，可以将AR眼镜的微型显示器发出的虚拟图像在x轴负半轴方向上进行出瞳扩展，即实现虚拟的一维扩瞳，下文将进行详细描述。Based on the above description, it can be seen that for the diffractive optical waveguide 100 shown in FIGS. When exiting a certain position of the grating 103, a part of the light is released from the waveguide substrate 104 through diffraction, while another part of the light continues to propagate through the total reflection in the waveguide, and the above phenomenon is repeated at different positions of the outcoupling grating 103, so that the light source The incident light at 106 is duplicated in multiple copies along the positive half-axis of the x-axis, so that the light coupled out through the outcoupling grating 103 will also be amplified in the negative half-axis of the x-axis. This phenomenon can be called exit pupil expansion. For the diffractive optical waveguide 100 shown in FIGS. The exit pupil is expanded in the direction of the negative semi-axis, that is, a virtual one-dimensional pupil expansion is realized, which will be described in detail below.

可以理解，在传统光学成像***中，图像通常只有一个“出口”，叫做出It can be understood that in traditional optical imaging systems, there is usually only one "exit" for the image, which is called the exit

瞳。例如，假设进入波导“入瞳”的是直径4毫米的光束，由于光波导只负责传输而并不把图像放大缩小等，那么“出瞳”的也是4毫米的光束，在这种情况下人眼的瞳孔中心能看到图像的移动范围只有4毫米。通过在表面设置衍射光栅能够将出瞳沿水平方向复制了多份，每一个出瞳都输出相同的图像，使得人眼的瞳孔中心能看到图像的移动范围增大，即使眼睛在大范围移动时都能看到图像，称为出瞳扩展。Hitomi. For example, assuming that the beam entering the "entrance pupil" of the waveguide is a beam with a diameter of 4 mm, since the optical waveguide is only responsible for transmission and does not enlarge or reduce the image, etc., then the "exit pupil" is also a beam of 4 mm. In this case, people The pupil center of the eye can see the image within only 4 millimeters of movement. By setting a diffraction grating on the surface, the exit pupil can be duplicated in the horizontal direction, and each exit pupil outputs the same image, so that the center of the pupil of the human eye can see that the movement range of the image increases, even if the eye moves in a large range The image can be seen at any time, which is called exit pupil dilation.

(五)采用衍射光波导的AR眼镜(5) AR glasses using diffractive optical waveguides

图9示出了一种采用衍射光波导100作为镜片的AR眼镜200的结构示意图。FIG. 9 shows a schematic structural view of an AR glasses 200 using a diffractive optical waveguide 100 as a lens.

如图9所示，AR眼镜200可以包括镜架部分和镜片部分，其中镜架部分可以包括左镜腿201、右镜腿202和镜片框架203，镜片部分可以包括左镜片204和右镜片205，其中左镜片204和右镜片205可以采用衍射光波导结构，具体的，左镜片204和右镜片205均可以整个或部分采用衍射光波导100的波导衬底，例如，图9中示出了采用图8所示的衍射光波导100作为镜片的示意图。另外，AR眼镜200上还包括用于投射虚拟图像的微型显示装置105，通过微型显示装置105将虚拟图像投射入衍射光波导100制成的左镜片204和右镜片205，进而通过左镜片204和右镜片205将虚拟图像导入人眼。As shown in FIG. 9, the AR glasses 200 may include a frame part and a lens part, wherein the frame part may include a left temple 201, a right temple 202 and a lens frame 203, and the lens part may include a left lens 204 and a right lens 205, Wherein the left lens 204 and the right lens 205 can adopt a diffractive waveguide structure, specifically, both the left lens 204 and the right lens 205 can adopt the waveguide substrate of the diffractive waveguide 100 in whole or in part, for example, Fig. 8 shows a schematic diagram of the diffractive optical waveguide 100 as an optical lens. In addition, the AR glasses 200 also include a micro-display device 105 for projecting virtual images, through the micro-display device 105, the virtual images are projected into the left lens 204 and the right lens 205 made of the diffractive optical waveguide 100, and then through the left lens 204 and The right lens 205 guides the virtual image into the human eye.

在一些实施例中，微型显示装置105可以设于镜片框架的中部，用于向左镜片204和右镜片205中的耦入光栅101投射光线。此外，在其他实施例中，微型显示装置也可以设置两个，例如，分别设于左镜腿201或右镜腿202上，或者可以设于左镜腿201或右镜腿202上朝向人眼前方的延伸区域。In some embodiments, the micro-display device 105 can be arranged in the middle of the lens frame for projecting light to the in-coupling grating 101 in the left lens 204 and the right lens 205 . In addition, in other embodiments, two micro-display devices can also be provided, for example, they are respectively arranged on the left temple 201 or the right temple 202, or can be arranged on the left temple 201 or the right temple 202 facing people's eyes square extension area.

在一些实施例中，微型显示装置105可以包括微型显示器1051(如图10所示)和准直透镜1052(如图10所示)。其中，微型显示器1051用来提供虚拟图像，可以是自发光的有源器件，比如发光二极管面板，也可以是需要外部光源照明的液晶显示屏，还可以为基于微机电***技术的数字微镜阵列和激光束扫描仪等。准直透镜1052可以用于将各虚拟图像点的光线转换为平行的光束投射入耦入光栅101。In some embodiments, the microdisplay device 105 may include a microdisplay 1051 (as shown in FIG. 10 ) and a collimating lens 1052 (as shown in FIG. 10 ). Wherein, the microdisplay 1051 is used to provide a virtual image, which can be a self-illuminating active device, such as a light-emitting diode panel, or a liquid crystal display that needs external light source illumination, or a digital micromirror array based on MEMS technology. and laser beam scanners etc. The collimator lens 1052 can be used to convert the light rays of each virtual image point into parallel light beams and project them into the coupling grating 101 .

图10示出了虚拟图像通过AR眼镜200的左镜片204或右镜片205耦入人眼的原理示意图。FIG. 10 shows a schematic diagram of the principle of coupling a virtual image into human eyes through the left lens 204 or the right lens 205 of the AR glasses 200 .

如图10所示，微型显示器1051发出的点光线经准直透镜1052后转换为一束平行的光束投射入耦入光栅101，耦入光栅101将光束耦入波导衬底104后，光线在波导衬底104内全反射传播，在全反射传播的过程中，每次遇到波导衬底104表面的耦出光栅103，会有一部分光继续通过衍射释放出来进入眼睛，剩下的一部分光继续在波导中传播，直到下一次打到波导表面的耦出光栅103上，实现x方向的出瞳扩展。As shown in Figure 10, the point light emitted by the microdisplay 1051 is converted into a bundle of parallel light beams after being passed through the collimating lens 1052 and projected into the coupling grating 101. The total reflection propagation in the substrate 104, during the total reflection propagation process, every time it encounters the outcoupling grating 103 on the surface of the waveguide substrate 104, a part of the light will continue to be released into the eye through diffraction, and the remaining part of the light will continue to enter the eye. propagating in the waveguide until hitting the outcoupling grating 103 on the surface of the waveguide next time to realize exit pupil expansion in the x direction.

然而，如前所述，对于图9所示的AR眼镜200中的镜片所采用的衍射光波导100，存在只能在一个方向上进行图像的出瞳扩展，例如由微型显示器1051提供的虚拟图像，在经过耦出光栅103导出时，只在横向(如图9中的x轴方向)或者竖向(如图9中的y轴方向)上被放大，故存在导出的图像难以适用于不同瞳距、不同脸型及不同鼻梁高度的人群的问题。However, as mentioned above, for the diffractive optical waveguide 100 used in the lens in the AR glasses 200 shown in FIG. , when deriving through the outcoupling grating 103, it is only enlarged horizontally (as shown in the x-axis direction in Figure 9) or vertically (as shown in the y-axis direction in Figure 9), so the derived image is difficult to apply to different pupils Problems of people with different distances, different face shapes and different nose bridge heights.

为了解决上述出瞳扩展方向单一的问题，图11示出了一种衍射光波导100的结构示意图。在图11中示出的衍射光波导100中，通过在耦入光栅和耦出光栅的光路之间增加中继光栅，来实现在横竖两个方向上的出瞳扩展，使得用户能够观察到更大的图像视野范围，能够更好的适用于不同瞳距、不同脸型及不同鼻梁高度的人群。In order to solve the above-mentioned problem of a single exit pupil expansion direction, FIG. 11 shows a schematic structural diagram of a diffractive optical waveguide 100 . In the diffractive optical waveguide 100 shown in Fig. 11, by adding a relay grating between the optical paths of the in-coupling grating and the out-coupling grating, the exit pupil expansion in the horizontal and vertical directions is realized, so that the user can observe more The large image field of view is better suitable for people with different interpupillary distances, different face shapes and different nose bridge heights.

具体地，图11所示的衍射光波导100可以包括波导衬底104、耦入光栅101、中继光栅102和耦出光栅103。其中，图11所示的耦入光栅101、中继光栅102和耦出光栅103均位于波导衬底104的上表面上，且均为衍射光栅结构。Specifically, the diffractive optical waveguide 100 shown in FIG. 11 may include a waveguide substrate 104 , an in-coupling grating 101 , a relay grating 102 and an out-coupling grating 103 . Wherein, the in-coupling grating 101 , the relay grating 102 and the out-coupling grating 103 shown in FIG. 11 are all located on the upper surface of the waveguide substrate 104 , and are all diffraction grating structures.

可以理解，在本申请的其他实施例中，耦入光栅101、中继光栅102和耦出光栅103也可以均位于波导衬底104的下表面或者三者分别分布于波导衬底104的上下两个表面上，不限于图11所示的位置设置。此外，虽然图11所示的耦入光栅101为圆形、中继光栅102为梯形、耦出光栅103为长方形，但是，图11中所示的形状仅仅是示例性的，可以根据实际光学设计需求或者AR镜片的形状需求，将三者设置为任意形状。It can be understood that, in other embodiments of the present application, the coupling-in grating 101, the relay grating 102, and the coupling-out grating 103 may all be located on the lower surface of the waveguide substrate 104, or the three may be respectively distributed on the upper and lower sides of the waveguide substrate 104. On the surface, it is not limited to the position setting shown in Figure 11. In addition, although the in-coupling grating 101 shown in FIG. 11 is circular, the relay grating 102 is trapezoidal, and the out-coupling grating 103 is rectangular, the shapes shown in FIG. According to the requirements or the shape requirements of the AR lens, set the three to any shape.

为了能够实现横竖两个方向上的出瞳扩展，如图11所示，中继光栅102的光栅刻痕方向可以与耦入光栅101的光栅刻痕方向呈设定角度，便于从耦入光栅101耦入的光线在传播过程中遇到中继光栅102的时候一部分光被改变方向朝向耦出光栅103的方向传播，即一部分继续在波导衬底104中以y轴负半轴为引导方向全反射传播，其余部分继续沿原来的方向传播，即以x轴正半轴为引导方向全反射传播。例如，图11所示的衍射光波导100中，中继光栅102的刻痕方向与耦入光栅101的光栅刻痕方向设置为呈45度角，以实现上述功能。具体地，图12中(a)和(b)分别示出了在不同视角下光线在衍射光波导100中的导向示意图。In order to be able to expand the exit pupil in both horizontal and vertical directions, as shown in FIG. When the coupled-in light encounters the relay grating 102 during the propagation process, a part of the light is changed to propagate towards the direction of the out-coupling grating 103, that is, a part continues to be totally reflected in the waveguide substrate 104 with the negative semi-axis of the y-axis as the guiding direction Propagate, and the rest continue to propagate along the original direction, that is, total reflection propagation with the positive semi-axis of the x-axis as the guiding direction. For example, in the diffractive optical waveguide 100 shown in FIG. 11 , the notch direction of the relay grating 102 and the grating notch direction of the coupling grating 101 are set at an angle of 45 degrees to realize the above functions. Specifically, (a) and (b) in FIG. 12 respectively show schematic diagrams of guiding light in the diffractive optical waveguide 100 under different viewing angles.

如图12中(a)所示，微型显示装置105发出的光线i1在入射到耦入光栅101后，通过耦入光栅101的衍射被耦入波导衬底104，并在波导衬底104中沿x轴正半轴全反射传播。经耦入光栅101耦入的光线i1在遇到中继光栅102后，由于中继光栅的分光特性，光线被分为两个部分，分别朝向不同的衍射角度全反射传播。具体地，其中一部分在波导衬底104中继续沿x轴正半轴方向全反射前进，如图中的箭头B1所示；另一部分在波导衬底104中沿y轴负半轴的方向全反射前进，如图中的箭头B2所示。其中，遇到中继光栅102后沿y轴负半轴的方向全反射前进的光线被导入耦出光栅103，由耦出光栅103耦出波导衬底104，耦出的光线的行进方向如图中的箭头B3所示，即z轴正半轴方向。As shown in (a) of FIG. 12 , after the light i1 emitted by the microdisplay device 105 is incident on the coupling grating 101, it is coupled into the waveguide substrate 104 through the diffraction of the coupling grating 101, and travels in the waveguide substrate 104 along the X-axis positive half-axis total reflection propagation. After encountering the relay grating 102, the light i1 coupled in through the coupling grating 101 is divided into two parts due to the spectroscopic characteristics of the relay grating, and propagates toward different diffraction angles with total reflection. Specifically, a part of them is totally reflected in the waveguide substrate 104 along the direction of the positive half-axis of the x-axis, as shown by arrow B1 in the figure; the other part is totally reflected in the direction of the negative half-axis of the y-axis in the waveguide substrate 104 Go forward, as shown by arrow B2 in the figure. Wherein, after encountering the relay grating 102, the light totally reflected along the direction of the negative semi-axis of the y-axis is guided into the outcoupling grating 103, and is coupled out of the waveguide substrate 104 by the outcoupling grating 103. The traveling direction of the outcoupled light is shown in the figure Indicated by the arrow B3, that is, the direction of the positive semi-axis of the z-axis.

具体地，图13中(a)和(b)分别示出了光线在中继光栅102和耦出光栅103处的衍射光路图。Specifically, (a) and (b) in FIG. 13 show the diffraction light path diagrams of the light at the relay grating 102 and the outcoupling grating 103 respectively.

可以理解，在本申请各实施例中，对于二维的光路图，从平面入射的光线用圆圈中加入“x”符号来表示。It can be understood that, in each embodiment of the present application, for a two-dimensional light path diagram, a light incident from a plane is indicated by adding an "x" symbol into a circle.

如图13中(a)所示，被耦入光栅101耦入后在波导衬底104中沿x轴正半轴全反射传播的光线i1入射到中继光栅102的H1位置时，光线被分为两个部分，分别朝向不同的衍射角度传播。具体地，一部分光线i3继续入射到波导衬底104的另一表面沿x轴正半轴进行全反射传播，而另一部分光线i2沿垂直于图像向内的方向进入波导衬底104，并沿y轴负半轴向着耦出光栅103进行全反射传播。可以理解，光线i3入射到中继光栅102的其他位置,例如H2位置时，也会重复上述过程，分出分别沿x轴正半轴和y轴负半轴全反射传播的光线i4和i5。如此，中继光栅102使得光线i1沿x轴正半轴的全反射传播在x轴正半轴扩展了光线，即对于微型显示装置105发出的虚拟图像，在x轴正半轴方向上被出瞳扩展。As shown in (a) of FIG. 13 , when the light i1 that is coupled into the grating 101 and travels in the waveguide substrate 104 through total reflection along the positive semi-axis of the x-axis is incident on the H1 position of the relay grating 102, the light is split into into two parts, respectively propagating towards different diffraction angles. Specifically, a part of the light i3 continues to be incident on the other surface of the waveguide substrate 104 for total reflection along the positive half axis of the x-axis, while another part of the light i2 enters the waveguide substrate 104 along the inward direction perpendicular to the image, and travels along the y The negative half axis propagates through total reflection toward the outcoupling grating 103 . It can be understood that when the ray i3 is incident on other positions of the relay grating 102, such as the position H2, the above-mentioned process will be repeated, and the light i4 and i5 which propagate along the positive half-axis of the x-axis and the negative half-axis of the y-axis are totally reflected respectively. In this way, the relay grating 102 makes the total reflection of the ray i1 along the positive half-axis of the x-axis expand the light rays along the positive half-axis of the x-axis, that is, for the virtual image emitted by the micro-display device 105, it is emitted in the direction of the positive half-axis of the x-axis. Pupil dilation.

类似图8中(c)，如图13中(b)所示，上述沿y轴负半轴向着耦出光栅103进行全反射传播的光线i2到达耦出光栅103的位置D1时，会有一部分光线i21通过光栅衍射释放出去，即被耦出波导衬底104，而剩下的一部分光线i22继续在波导衬底104中进行全反射传播。光线i22在后续传播的过程中，当入射到波导衬底104表面的耦出光栅103上的位置D2时，重复上述现象。如此，光线i1在y轴负半轴方向被扩展，即对于微型显示装置105发出的虚拟图像，在y轴负半轴方向上被出瞳扩展。Similar to (c) in FIG. 8 , as shown in (b) in FIG. 13 , when the above-mentioned light i2 that is totally reflected and propagated along the negative half-axis of the y-axis toward the outcoupling grating 103 reaches the position D1 of the outcoupling grating 103, there will be A part of light i21 is released through grating diffraction, that is, is coupled out of the waveguide substrate 104 , while the remaining part of light i22 continues to propagate in the waveguide substrate 104 through total reflection. During subsequent propagation, when the light i22 is incident on the position D2 on the outcoupling grating 103 on the surface of the waveguide substrate 104 , the above phenomenon is repeated. In this way, the ray i1 is expanded in the direction of the negative half-axis of the y-axis, that is, for the virtual image emitted by the micro-display device 105 , it is expanded by the exit pupil in the direction of the negative half-axis of the y-axis.

从上述描述可以看出，图11至图13所示的衍射光波导100可以实现x轴正半轴和y轴负半轴两个方向的出瞳扩展，应用于AR眼镜时，使得用户能够观察到更大的图像视野范围，能够更好的适用于不同瞳距、不同脸型及不同鼻梁高度的人群。It can be seen from the above description that the diffractive optical waveguide 100 shown in Figures 11 to 13 can realize exit pupil expansion in both directions of the positive x-axis and the negative y-axis. When applied to AR glasses, users can observe To a larger image field of view, it can be better suitable for people with different interpupillary distances, different face shapes and different nose bridge heights.

图14示出了一种采用上述衍射光波导100作为镜片的AR眼镜200的结构示意图。如图14所示，AR眼镜200的左镜片201和右镜片201可以均采用图14所示的衍射光波导100。其中，图15中AR眼镜200的其他部分结构与图10中类似，在此不再赘述。FIG. 14 shows a schematic structural view of an AR glasses 200 using the diffractive optical waveguide 100 as a lens. As shown in FIG. 14 , the left lens 201 and the right lens 201 of the AR glasses 200 may both use the diffractive optical waveguide 100 shown in FIG. 14 . Wherein, other parts of the structure of the AR glasses 200 in FIG. 15 are similar to those in FIG. 10 , and will not be repeated here.

然而，图11至图13所示的衍射光波导100虽然可以实现x轴正半轴和y轴负半轴两个方向的出瞳扩展，但是，若想要满足AR眼镜进一步增大竖直视场角的市场需求，即若需要进一步增大人眼看到竖直视场范围，则需要增大衍射光波导100的中继光栅102的面积才能实现，而由于衍射光波导100在作为AR眼镜的镜片时面积有限，故中继光栅102的面积受限，图11至图13所示的衍射光波导100难以满足AR眼镜进一步增大竖直视场角的需求。However, although the diffractive optical waveguide 100 shown in Fig. 11 to Fig. 13 can realize exit pupil expansion in both directions of the positive x-axis and the negative y-axis, if the AR glasses are desired to further increase the vertical viewing angle The market demand for the field angle, that is, if it is necessary to further increase the range of the vertical field of view seen by the human eye, it is necessary to increase the area of the relay grating 102 of the diffractive optical waveguide 100 to achieve it. Since the area is limited, the area of the relay grating 102 is limited. The diffractive optical waveguide 100 shown in FIGS.

为了更详细的描述该问题，首先介绍视场的概念。具体地，一般采用视场角衡量人眼能够看到的视场范围的大小。例如，如图15所示，以观察者眼睛能看到的图像为例，视场角就是图像边缘与眼睛连线的夹角,可以包括水平视场角和竖直视场角；例如在图15中，AOB角就是水平视场角，BOC就是竖直视场角，在y方向进行光瞳复制,可以增大竖直视场角；在x方向进行光瞳复制,可以增大水平视场角。In order to describe this problem in more detail, the concept of field of view is first introduced. Specifically, the field angle is generally used to measure the size of the field of view that can be seen by human eyes. For example, as shown in Figure 15, taking the image that the observer's eyes can see as an example, the angle of view is the angle between the edge of the image and the line connecting the eyes, which may include a horizontal angle of view and a vertical angle of view; for example, in Fig. In 15, the AOB angle is the horizontal field of view, BOC is the vertical field of view, the pupil copy in the y direction can increase the vertical field of view; the pupil copy in the x direction can increase the horizontal field of view horn.

具体地，结合上述视场角概念到本申请的AR眼镜200，AR眼镜200的微型显示装置105发射出的虚拟图像(如图16中(a)和中(b)中的微型显示装置105中的虚线框所示)一般包括上边缘视场S1和下边缘视场S2(如图16中(a)和中(b)所示)，其中，上边缘视场S1可以定义为微型显示装置105发出的虚拟图像的上边缘的其中一个光点的光线，下边缘视场S2可以定义为虚拟图像的下边缘的与上述上边缘的光点对应的光点的光线；例如，上边缘视场S1可以定义为虚拟图像的上边缘的中点P1的光线，下边缘视场S2可以定义为虚拟图像的下边缘的中点P2的光线；上边缘视场S2和下边缘视场S1的夹角称为边缘视场夹角。虚拟图像的边缘视场夹角能够影响人眼所能看到的竖直视场范围，即竖直视场角的大小与图像的边缘视场夹角一致，其具体关系为：竖直视场角随边缘视场夹角的增大而增大。因此，若要增大人眼能够看到的竖直视场范围，即竖直视场角，则需增大图像的边缘视场夹角。若采用图11中所示的衍射光波导，在增大图像的边缘视场夹角的情况下，则需增大中继光栅102的面积才能实现同样的尺寸的出瞳，因此，会导致整个衍射光波导100的面积的增大，其具体原因如下：Specifically, combining the above concept of viewing angle with the AR glasses 200 of the present application, the virtual image emitted by the micro display device 105 of the AR glasses 200 (as shown in the micro display device 105 in (a) and (b) of FIG. 16 shown in the dotted line box) generally includes an upper edge field of view S1 and a lower edge field of view S2 (as shown in (a) and middle (b) of Figure 16), wherein the upper edge field of view S1 can be defined as the microdisplay device 105 The light of one of the light spots on the upper edge of the emitted virtual image, the lower edge field of view S2 can be defined as the light of the light point corresponding to the light point on the upper edge of the lower edge of the virtual image; for example, the upper edge field of view S1 It can be defined as the ray at the midpoint P1 of the upper edge of the virtual image, and the lower edge field of view S2 can be defined as the ray at the midpoint P2 of the lower edge of the virtual image; the angle between the upper edge field of view S2 and the lower edge field of view S1 is called is the angle of the peripheral field of view. The angle of the edge field of view of the virtual image can affect the range of the vertical field of view that the human eye can see, that is, the size of the vertical field of view is consistent with the angle of the edge field of view of the image. The specific relationship is: vertical field of view The angle increases with the increase of the angle between the peripheral field of view. Therefore, in order to increase the range of the vertical field of view that can be seen by human eyes, that is, the vertical field of view angle, it is necessary to increase the included angle of the edge field of view of the image. If the diffractive optical waveguide shown in Fig. 11 is used, in the case of increasing the angle of the peripheral field of view of the image, it is necessary to increase the area of the relay grating 102 to achieve the exit pupil of the same size, therefore, the entire The specific reasons for the increase in the area of the diffractive optical waveguide 100 are as follows:

如图16中(a)和(b)所示，图16中(a)和(b)分别示出了较小边缘视场夹角A1和较大边缘视场夹角A2的图像在11中所示的衍射光波导结构中传播的导向对比示意图。如图16中(a)和(b)所示，虚拟图像包括上边缘视场S1和下边缘视场S2。虚拟图像的上边缘视场S1和下边缘视场S2在波导中逐渐分散开，而上边缘视场S1和下边缘视场S2也必须要在中继光栅102中传播才能实现X方向的出瞳扩展；因此，如图16中(a)和(b)所示，随着边缘视场夹角从A1增大到A2，上边缘视场S1和下边缘视场S2分散程度增大，若光线想要继续延x方向实现同样尺寸的出瞳，则中继光栅102的面积需要沿上边缘视场S1和下边缘视场S2的延伸方向扩大，即图16中(b)所示梯形的中继光栅102的较长的底边则需要加长，两个腰也需要向外扩大。因而，增大图像边缘视场夹角会导致中继光栅102面积的增大，进而导致整个波导结构的增大。反言之，若不增大中继光栅102的面积，则光线打到中继光栅102上的次数会减少，导致在x方向的出瞳尺寸会减小。As shown in (a) and (b) in Figure 16, (a) and (b) in Figure 16 show the images of the smaller edge angle of view A1 and the larger edge angle of view A2 respectively in 11 Schematic diagram of the guide contrast propagating in the diffractive optical waveguide structure shown. As shown in (a) and (b) of FIG. 16 , the virtual image includes an upper edge field of view S1 and a lower edge field of view S2 . The upper edge field of view S1 and the lower edge field of view S2 of the virtual image are gradually dispersed in the waveguide, and the upper edge field of view S1 and the lower edge field of view S2 must also propagate in the relay grating 102 to realize the exit pupil in the X direction Therefore, as shown in (a) and (b) in Figure 16, as the angle of the peripheral field of view increases from A1 to A2, the degree of dispersion of the upper edge field of view S1 and the lower edge field of view S2 increases, if the light If you want to continue extending along the x direction to achieve the same exit pupil size, the area of the relay grating 102 needs to expand along the extension direction of the upper edge field of view S1 and the lower edge field of view S2, that is, the center of the trapezoid shown in (b) in Figure 16 Following the longer base of the grating 102 needs to be lengthened, the two waists also need to expand outward. Therefore, increasing the included angle of the field of view at the edge of the image will result in an increase in the area of the relay grating 102 , which in turn will result in an increase in the entire waveguide structure. Conversely, if the area of the relay grating 102 is not increased, the number of times the light hits the relay grating 102 will decrease, resulting in a decrease in the size of the exit pupil in the x direction.

为解决该问题，本申请实施例提供另一种衍射光波导100，将图11所示的衍射光波导100中的中继光栅102从一个光栅变为多个折射率不同的光栅，被耦入光栅101耦入的光线在进入波导衬底104之后依然在波导衬底104中全反射传播，但是全反射传播的光线一部分的行径方向被限制在多个中继光栅之间，一部分光线可以在靠近耦出光栅103的中继光栅处被改变方向，朝着耦出光栅103全反射行径，最终被耦出光栅103耦出至人眼。如此，使得光线在多个中继光栅之间通过往复全反射传播实现出瞳扩展，且无需随着竖直视场角的增大而增大中继光栅的面积。下面将结合具体的实施例进行说明。In order to solve this problem, the embodiment of the present application provides another diffractive optical waveguide 100. The relay grating 102 in the diffractive optical waveguide 100 shown in FIG. The light coupled in by the grating 101 is still propagating in the waveguide substrate 104 through total reflection after entering the waveguide substrate 104, but the travel direction of a part of the light propagating through the total reflection is limited between multiple relay gratings, and a part of the light can travel close to the waveguide substrate 104. The direction of the relay grating of the outcoupling grating 103 is changed, and it travels towards the outcoupling grating 103 for total reflection, and is finally outcoupled by the outcoupling grating 103 to human eyes. In this way, the light propagates between the multiple relay gratings through reciprocating total reflection to realize the expansion of the exit pupil, and there is no need to increase the area of the relay gratings as the vertical viewing angle increases. The following will be described in combination with specific embodiments.

图17为本申请实施例一种包括两个中继光栅的衍射光波导100的示意图。FIG. 17 is a schematic diagram of a diffractive optical waveguide 100 including two relay gratings according to an embodiment of the present application.

如图17所示，衍射光波导100可以包括波导衬底104、耦入光栅101、第一中继光栅1021、第二中继光栅1022、以及耦出光栅103。其中，第一中继光栅1021和第二中继光栅1022平行设置且间隔第一距离，该第一距离的设置可以实现将从耦入光栅衍射的光线引导至在第一中继光栅1021和第二中继光栅1022之间往复全反射传播，下文将进行详细的描述。此外，耦出光栅103设于第一中继光栅1021和第二中继光栅1022之间。As shown in FIG. 17 , the diffractive optical waveguide 100 may include a waveguide substrate 104 , an incoupling grating 101 , a first relay grating 1021 , a second relay grating 1022 , and an outcoupling grating 103 . Wherein, the first relay grating 1021 and the second relay grating 1022 are arranged in parallel and separated by a first distance. The reciprocating total reflection propagation between the two relay gratings 1022 will be described in detail below. In addition, the outcoupling grating 103 is disposed between the first relay grating 1021 and the second relay grating 1022 .

本申请实施例中，第一中继光栅1021和第二中继光栅1022可以限定出中继区域，中继区域在第一方向延伸，第一中继光栅1021和第二中继光栅1022在第二方向排列，中继区域在第二方向上具有相对的第一边和第二边，第一边的延伸方向与第二边的延伸方向之间夹角小于第一角度；In the embodiment of the present application, the first relay grating 1021 and the second relay grating 1022 may define a relay area, the relay area extends in the first direction, and the first relay grating 1021 and the second relay grating 1022 Arranged in two directions, the relay area has a first side and a second side opposite to each other in the second direction, and the angle between the extension direction of the first side and the extension direction of the second side is smaller than the first angle;

例如，上述第一方向可以x轴方向，第二方向可以为y轴方向。For example, the above-mentioned first direction may be the x-axis direction, and the second direction may be the y-axis direction.

可以理解，中继区域可以由第一中继光栅1021和第二中继光栅1022靠近的栅线界定，是第一中继光栅1021和第二中继光栅1022之间的区域，不包括第一中继光栅1021和第二中继光栅1022。其中，第一边可以为第一中继光栅1021的与第二中继光栅1022最为邻近的栅线，第二边可以是第二中继光栅1022的与第一中继光栅1021最为邻近的栅线。It can be understood that the relay area can be defined by the grating lines close to the first relay grating 1021 and the second relay grating 1022, which is the area between the first relay grating 1021 and the second relay grating 1022, excluding the first A relay grating 1021 and a second relay grating 1022 . Wherein, the first side may be the grating line of the first relay grating 1021 that is closest to the second relay grating 1022, and the second side may be the grating line of the second relay grating 1022 that is the closest to the first relay grating 1021. Wire.

中继区域也可以由第一中继光栅1021和第二中继光栅1022相距最远的栅线界定，不仅包括第一中继光栅1021和第二中继光栅1022之间的区域，还包括第一中继光栅1021和第二中继光栅1022。其中，第一边可以为第一中继光栅1021的与第二中继光栅1022最为远离的栅线，第二边可以是第二中继光栅1022的与第一中继光栅1021最为远离的栅线。The relay area can also be defined by the farthest grating lines between the first relay grating 1021 and the second relay grating 1022, including not only the area between the first relay grating 1021 and the second relay grating 1022, but also the A relay grating 1021 and a second relay grating 1022 . Wherein, the first side may be the grating line of the first relay grating 1021 farthest from the second relay grating 1022, and the second side may be the grating line of the second relay grating 1022 farthest from the first relay grating 1021. Wire.

可以理解，本申请实施例中，第一中继光栅1021和第二中继光栅1022平行设置平行设置允许有一定的误差，例如，第一中继光栅1021和第二中继光栅1022的栅线或刻痕延伸方向可以具有一定的夹角，例如0-5度。It can be understood that in the embodiment of the present application, the parallel arrangement of the first relay grating 1021 and the second relay grating 1022 allows a certain error, for example, the grating lines of the first relay grating 1021 and the second relay grating 1022 Or the extending direction of the score may have a certain included angle, such as 0-5 degrees.

可以理解，虽然图17中所示的耦入光栅101、第一中继光栅1021、第二中继光栅1022、以及耦出光栅103均位于波导衬底104的同一表面上，但是，在其他实施例中，四者可以均位于波导衬底104的另一表面或者分布在不同表面上，例如，耦入光栅101和耦出光栅103位于光波导衬底104的同一表面，而第一中继光栅1021、第二中继光栅1022位于光波导衬底104的另一表面，在此不做限制。It can be understood that although the incoupling grating 101, the first relay grating 1021, the second relay grating 1022, and the outcoupling grating 103 shown in FIG. 17 are all located on the same surface of the waveguide substrate 104, in other implementation In an example, the four can all be located on another surface of the waveguide substrate 104 or distributed on different surfaces, for example, the coupling-in grating 101 and the coupling-out grating 103 are located on the same surface of the optical waveguide substrate 104, and the first relay grating 1021. The second relay grating 1022 is located on the other surface of the optical waveguide substrate 104, which is not limited here.

此外，可以理解，虽然图17中所示的中继光栅只有两个，即第一中继光栅1021和第二中继光栅1022，但是，在其他实施例中，中继光栅102也可以包括三个或三个以上的衍射率不同的光栅区域。In addition, it can be understood that although there are only two relay gratings shown in FIG. One or more grating regions with different diffraction indices.

图18中(a)和(b)分别为本申请实施例光线在波导衬底中传播的不同角度的导向的示意图。(a) and (b) in FIG. 18 are schematic diagrams of different angles of guidance of light propagating in the waveguide substrate according to the embodiment of the present application.

可以理解，由于光线是在波导衬底104中全反射传播，第一中继光栅1021、第二中继光栅1022、或者耦出光栅103位于波导衬底104的两个不同底面全反射传播方向的引导作用均是相同的，故耦入光栅101、第一中继光栅1021、第二中继光栅1022、以及耦出光栅103不论是位于波导衬底104的哪个底面，光线在波导衬底104中传播的导向示意图均可以由图18中(a)和(b)表示。It can be understood that since the light propagates through total reflection in the waveguide substrate 104, the first relay grating 1021, the second relay grating 1022, or the outcoupling grating 103 are located at two different bottom surfaces of the waveguide substrate 104 in the direction of total reflection propagation. The guiding functions are the same, so no matter which bottom surface of the waveguide substrate 104 the in-coupling grating 101, the first relay grating 1021, the second relay grating 1022, and the out-coupling grating 103 are located on, the light will pass through the waveguide substrate 104. The schematic diagrams of the propagation guidance can be represented by (a) and (b) in Figure 18 .

如图18中(a)和(b)所示，微型显示装置105发出的光线i1在入射到耦入光栅101后，被耦入光栅101的耦入波导衬底104，并在波导衬底104中朝向第二中继光栅1022的方向进行全反射传播，如图中箭头B1所示。经耦入光栅101耦入的光线i1在遇到第二中继光栅1022的后，如前所述，通过衍射光栅的分光特性，光线被分为两个部分，分别朝向不同的衍射角度全反射传播。具体地，其中一部分在波导衬底104中朝向第一中继光栅1021的方向进行全反射传播,如图中的箭头B2所示；另一部分朝向如图中的箭头B3所示方向被引导至耦出光栅103，并由耦出光栅103耦出波导衬底104，耦出的光线的行进方向如图中的箭头B5(z轴正半轴方向)所示，传递至第一中继光栅1021的光线被全反射，并沿箭头B4所示引导方向被重新引导至第二中继光栅1022,在后续过程中，重复上述过程。As shown in (a) and (b) in Figure 18, after the light i1 emitted by the micro display device 105 is incident on the in-coupling grating 101, it is coupled into the in-coupling waveguide substrate 104 of the grating 101, and passes through the waveguide substrate 104 Total reflection propagation is carried out towards the direction of the second relay grating 1022, as shown by arrow B1 in the figure. After the light i1 coupled in through the coupling grating 101 encounters the second relay grating 1022, as mentioned above, the light is divided into two parts through the spectroscopic characteristics of the diffraction grating, which are totally reflected towards different diffraction angles respectively. spread. Specifically, a part of them propagates in the waveguide substrate 104 towards the first relay grating 1021 through total reflection, as shown by the arrow B2 in the figure; the other part is guided to the coupling out of the grating 103, and coupled out of the waveguide substrate 104 by the outcoupling grating 103, the traveling direction of the outcoupled light is shown by the arrow B5 (direction of the positive semi-axis of the z-axis) in the figure, and transmitted to the first relay grating 1021 The light is totally reflected and redirected to the second relay grating 1022 along the guiding direction indicated by the arrow B4. In the subsequent process, the above process is repeated.

具体地，图19中(a)示出了光线在第一中继光栅1021和第二中继光栅1022处的衍射光路图。Specifically, (a) in FIG. 19 shows the diffraction light path diagram of the light at the first relay grating 1021 and the second relay grating 1022 .

如图19中(a)所示，经耦入光栅101耦入后在波导衬底104中沿箭头B1所示方向全反射传播的光线i1入射到第二中继光栅1022的F1位置时，光线被分为两个部分，分别朝向不同的衍射角度传播，例如，一部分光线i2入射到波导衬底104的另一表面并沿箭头B2所示方向在波导衬底104的上下表面之间进行全反射传播，直到传播至第一中继光栅1021的G1位置；另一部分光线i3入射到波导衬底104的另一表面并沿箭头B3(如图18中(a)-(b)所示)所示方向进行全反射传播直到被引导至耦出光栅；传播至第一中继光栅1021的G1位置的光线i2被全反射至波导衬底的另一表面，并沿箭头B4所示方向在波导衬底104的上下表面之间进行全反射传播，直到光线i2打到第二中继光栅1021的F2位置时，重复上述过程，例如，将光线i2分为两部分，其中一部分光线i4被引导至朝向第一中继光栅1021的G2位置进行全反射传播，另一部分光线i5被引导至朝向耦出光栅103的位置进行全反射传播。如此，光线i1以在第一中继光栅1021和第二中继光栅1022间进行往复传播的方式实现了在x轴正半轴方向上的出瞳扩展。As shown in (a) of FIG. 19 , when the light i1 that is coupled in by the coupling grating 101 and propagating in the waveguide substrate 104 along the direction indicated by the arrow B1 is totally reflected and propagating, when it enters the position F1 of the second relay grating 1022, the light i1 is divided into two parts, which propagate towards different diffraction angles respectively. For example, a part of light i2 is incident on the other surface of the waveguide substrate 104 and is totally reflected between the upper and lower surfaces of the waveguide substrate 104 along the direction indicated by arrow B2 propagating until it reaches the G1 position of the first relay grating 1021; another part of the light i3 is incident on the other surface of the waveguide substrate 104 and moves along the arrow B3 (as shown in (a)-(b) in Figure 18) The direction of total reflection propagates until it is guided to the outcoupling grating; the light i2 propagating to the G1 position of the first relay grating 1021 is totally reflected to the other surface of the waveguide substrate, and travels along the direction shown by arrow B4 on the waveguide substrate The total reflection propagates between the upper and lower surfaces of 104, until the light i2 hits the F2 position of the second relay grating 1021, repeat the above process, for example, divide the light i2 into two parts, and one part of the light i4 is guided to the second relay grating 1021. The position G2 of a relay grating 1021 undergoes total reflection propagation, and another part of light i5 is guided to the position of the outcoupling grating 103 for total reflection propagation. In this way, the light i1 realizes the expansion of the exit pupil in the direction of the positive semi-axis of the x-axis in the way of reciprocating propagation between the first relay grating 1021 and the second relay grating 1022 .

类似图8中(c)，如图19中(b)所示，上述沿B3方向向着耦出光栅103进行全反射传播的光线i3到达耦出光栅103的位置D1时，会有一部分光线i6通过光栅衍射释放出去，即朝向z轴正半轴方向被耦出波导衬底104，而剩下的一部分光线i7继续在波导衬底104中进行全反射传播。光线i7在后续传播的过程中，当入射到波导衬底104表面的耦出光栅103上的位置D2时，重复上述现象。如此，光线i1在y轴负半轴方向被扩展，即对于微型显示装置105发出的虚拟图像，在y轴负半轴方向上被出瞳扩展。Similar to (c) in FIG. 8 , as shown in (b) in FIG. 19 , when the above-mentioned ray i3 that is totally reflected and propagating toward the outcoupling grating 103 along the B3 direction reaches the position D1 of the outcoupling grating 103 , part of the light i6 will pass through The grating diffraction is released, that is, coupled out of the waveguide substrate 104 toward the positive semi-axis of the z-axis, and the remaining part of light i7 continues to propagate in the waveguide substrate 104 through total reflection. During subsequent propagation, when the light i7 is incident on the position D2 on the outcoupling grating 103 on the surface of the waveguide substrate 104 , the above phenomenon is repeated. In this way, the ray i1 is expanded in the direction of the negative half-axis of the y-axis, that is, for the virtual image emitted by the micro-display device 105 , it is expanded by the exit pupil in the direction of the negative half-axis of the y-axis.

本申请实施例中，采用光线第一中继光栅1021和第二中继光栅1022间全反射传播的方式实现x方向的出瞳扩展；而不是在中继光栅102区域以直线传播的方式实现x方向的出瞳扩展，能够使得在增大图像边缘视场之间的夹角的时候，不用增大中继光栅102区域的面积也可实现x方向的出瞳扩展。In the embodiment of the present application, the exit pupil expansion in the x direction is realized by the way of total reflection propagation between the first relay grating 1021 and the second relay grating 1022; The expansion of the exit pupil in the x direction can make the expansion of the exit pupil in the x direction possible without increasing the area of the relay grating 102 when increasing the angle between the peripheral fields of view of the image.

具体的，图20中(a)和(b)分别示出了较小边缘视场夹角A1和较大边缘视场夹角A2的图像在衍射光波导100中传播的导向对比示意图。如图20中(a)和(b)所示，在边缘视场夹角由小变大时，引起的变化如下：Specifically, (a) and (b) in FIG. 20 respectively show a schematic diagram of guide comparison of images with a small peripheral angle of view A1 and a relatively large peripheral angle of view A2 propagating in the diffractive optical waveguide 100 . As shown in (a) and (b) in Figure 20, when the angle of the peripheral field of view changes from small to large, the changes caused are as follows:

边缘视场的光线被耦入光栅101耦入后，被引导至第二中继光栅1022的引导方向改变，即引导方向与x轴正半轴的夹角增大，因为光线在中继光栅102为全反射式往复传播，光线经第二中继光栅1022衍射至第一中继光栅1021的引导方向会相应改变。因此，在边缘视场夹角由小变大时，引起的变化只是光线经第二中继光栅1022衍射至第一中继光栅1021的引导方向会相应改变，光线打到第一中继光栅1021上的次数并不会显著减少，因此，出瞳次数不会显著减小，即并不会显著影响光线的出瞳尺寸的变化。After the light in the peripheral field of view is coupled into the grating 101, the guiding direction guided to the second relay grating 1022 changes, that is, the angle between the guiding direction and the positive semi-axis of the x-axis increases, because the light passes through the relay grating 102 For total reflection reciprocating propagation, the guiding direction of light diffracted by the second relay grating 1022 to the first relay grating 1021 will change accordingly. Therefore, when the angle of the peripheral field of view changes from small to large, the only change is that the guiding direction of the light diffracted by the second relay grating 1022 to the first relay grating 1021 will change accordingly, and the light hits the first relay grating 1021 The number of times above will not be significantly reduced, therefore, the number of exit pupils will not be significantly reduced, that is, it will not significantly affect the change in the size of the exit pupil of light.

综上，本申请实施例提供的衍射光波导100在边缘视场夹角由小变大时，只会引起两个中继光栅对光线的引导方向的改变，而无需增大中继光栅的面积也能同样能实现x方向的同样尺寸的出瞳扩展。To sum up, when the diffractive optical waveguide 100 provided by the embodiment of the present application changes from small to large at the angle of the peripheral field of view, it will only cause a change in the guiding direction of light by the two relay gratings without increasing the area of the relay gratings. Exit pupil expansion of the same size in the x direction can also be achieved.

可以理解，在本申请实施例中，为了使得耦入光栅101的耦入效率达到95％以上，即使得耦入光栅101以特定角度将尽可能多的光线耦入到第二中继光栅1022，可以通过设计耦入光栅101的参数，例如，折射率n、光栅形状、厚度及占空比等，将所需的耦入光栅101的衍射效率优化到最高，从而使大部分光在衍射后主要沿这一方向传播。此外，为了降低单次耦出效率，使得光线在耦出光栅103中即实现某一特定方向的扩展又耦出到人眼，耦出光栅103的耦出效率可以为1％-10％，以便降低单次耦出效率，实现出瞳扩展。It can be understood that in the embodiment of the present application, in order to make the coupling efficiency of the coupling grating 101 reach more than 95%, that is, to make the coupling grating 101 couple as much light as possible into the second relay grating 1022 at a specific angle, By designing the parameters of the coupling-in grating 101, such as the refractive index n, grating shape, thickness and duty ratio, etc., the required diffraction efficiency of the coupling-in grating 101 can be optimized to the highest, so that most of the light is mainly propagate in this direction. In addition, in order to reduce the single outcoupling efficiency, so that the light can expand in a specific direction in the outcoupling grating 103 and be coupled out to the human eye, the outcoupling efficiency of the outcoupling grating 103 can be 1%-10%, so that Reduce single outcoupling efficiency and achieve exit pupil expansion.

此外，在本申请实施例中，为了使得耦出光栅103耦出的光线的k空间区域与微型显示装置105发射出的入射光的k空间区域完全重合，从而有效防止图像畸变的产生，需要对各光栅的参数进行设置。例如，设置耦出光栅103的周期及光栅矢量方向与耦入光栅101的周期及光栅矢量方向相一致；且设置第一中继光栅1021的周期及光栅矢量方向与第二中继光栅1022的周期及光栅矢量方向相一致。其中，本申请实施例中提及的光栅矢量方向为与光栅的刻痕方向垂直的方向。In addition, in the embodiment of the present application, in order to make the k-space region of the light coupled out from the grating 103 coincide completely with the k-space region of the incident light emitted by the micro-display device 105, so as to effectively prevent image distortion, it is necessary to The parameters of each grating are set. For example, setting the period and grating vector direction of the coupling-out grating 103 to be consistent with the period and grating vector direction of the coupling-in grating 101; It is consistent with the grating vector direction. Wherein, the vector direction of the grating mentioned in the embodiment of the present application is a direction perpendicular to the notch direction of the grating.

例如，如图17所示，耦入光栅101的刻痕方向与x轴正半轴正方向所成角度与耦出光栅103的刻痕方向与X轴正半轴正方向所成角度可以均为45°。第一中继光栅1021的刻痕方向和第二中继光栅1022的刻痕方向可以均为与x轴平行。For example, as shown in FIG. 17 , the angle formed between the direction of the inscription of the grating 101 and the positive direction of the positive semi-axis of the x-axis and the angle formed by the direction of the inscription of the out-coupling grating 103 and the positive direction of the positive semi-axis of the x-axis can be both 45°. The scoring direction of the first relay grating 1021 and the scoring direction of the second relay grating 1022 may both be parallel to the x-axis.

在一些实施例中，耦入光栅101刻痕方向与x轴正半轴正方向所成角度需要满足的条件为能够使得光线射至耦入光栅101能够被耦入光栅101引导至朝向第二中继光栅1022的方向进行传播，例如，可以为-70°至10°之间。In some embodiments, the condition that the angle formed by the score direction of the coupling-in grating 101 and the positive direction of the positive semi-axis of the x-axis needs to be satisfied is that the light incident on the coupling-in grating 101 can be guided by the coupling-in grating 101 toward the second center. The direction of propagation following the grating 1022, for example, may be between -70° and 10°.

本申请实施例中，为了保证光线可以被控制在由中继光栅所限定的中继区域内全反射式传播，第一中继光栅1021和第二中继光栅1022可以被设置有不同的衍射效率分布。In the embodiment of the present application, in order to ensure that light can be controlled to propagate through total reflection in the relay area defined by the relay grating, the first relay grating 1021 and the second relay grating 1022 can be set with different diffraction efficiencies distributed.

具体地，第一中继光栅1021的衍射效率要求如下：第一中继光栅1021的衍射效率分布可以为均匀分布，以使得入射到第一中继光栅1021上的光能够被全反射至第二中继光栅1022。例如，在一些实施例中，可以控制入射到第一中继光栅1021上的光在发生衍射时，出射出第一中继光栅1021衍射光线的衍射效率较小，例如，衍射效率设置为小于0.1％；而反射回第二中继光栅1022的衍射光线具有较高的衍射效率，例如，可以设置为大于99.5％，从而有效保证没有能量溢出中继光栅。Specifically, the requirements for the diffraction efficiency of the first relay grating 1021 are as follows: the distribution of the diffraction efficiency of the first relay grating 1021 can be a uniform distribution, so that the light incident on the first relay grating 1021 can be totally reflected to the second Relay grating 1022 . For example, in some embodiments, it can be controlled that when the light incident on the first relay grating 1021 is diffracted, the diffraction efficiency of the light diffracted by the first relay grating 1021 is relatively small, for example, the diffraction efficiency is set to be less than 0.1 %; while the diffracted light reflected back to the second relay grating 1022 has a relatively high diffraction efficiency, for example, can be set to be greater than 99.5%, so as to effectively ensure that no energy overflows the relay grating.

具体地，第二中继光栅1022的衍射效率要求如下：第二中继光栅1022可以具有不均匀的衍射效率，以使得有部分光线由第二中继光栅1022耦出进而进入耦出光栅103。例如，第二中继光栅1022中靠近耦出光栅103的一侧的部分衍射效率较低，靠近第一中继光栅1021的一侧的部分的衍射效率较高，从而能够有效保证有部分光线由第一中继光栅1021耦出进入耦出光栅103。例如，在一些实施例中，可以控制入射到第二中继光栅1022上的光发生衍射时，出射到耦出光栅103的衍射光线的衍射效率可以为0.5-20％，反射回第一中继光栅1021的衍射光的衍射效率大于80％，从而能够有效保证较少部分光线由第二中继光栅1021耦出进入耦出光栅103，而较多的光线继续反射回第一中继光栅1021，实现在x方向上的出瞳扩展。Specifically, the requirements for the diffraction efficiency of the second relay grating 1022 are as follows: the second relay grating 1022 may have non-uniform diffraction efficiency, so that some light is coupled out from the second relay grating 1022 and enters the outcoupling grating 103 . For example, in the second relay grating 1022, the diffraction efficiency of the part near the side of the outcoupling grating 103 is low, and the diffraction efficiency of the part near the side of the first relay grating 1021 is high, so that it can effectively ensure that part of the light is transmitted by The first relay grating 1021 couples out the incoupling grating 103 . For example, in some embodiments, when the light incident on the second relay grating 1022 can be controlled to diffract, the diffraction efficiency of the diffracted light that exits the outcoupling grating 103 can be 0.5-20%, and is reflected back to the first relay The diffraction efficiency of the diffracted light by the grating 1021 is greater than 80%, so that it can effectively ensure that less light is coupled out from the second relay grating 1021 and enters the outcoupling grating 103, while more light continues to be reflected back to the first relay grating 1021, Achieves exit pupil expansion in the x direction.

在一些实施例中，第一中继光栅1021和第二中继光栅1022可以均采用表面浮雕光栅，且其衍射效率可以通过表面浮雕光栅的光栅高度进行调制。例如，通过将第一中继光栅1021的光栅高度设置为均等分布，使得第一中继光栅1021的衍射效率均匀分布，如图3中(a)所示。In some embodiments, both the first relay grating 1021 and the second relay grating 1022 can be surface relief gratings, and their diffraction efficiency can be modulated by the grating height of the surface relief gratings. For example, by setting the grating heights of the first relay grating 1021 to be evenly distributed, the diffraction efficiency of the first relay grating 1021 is evenly distributed, as shown in (a) of FIG. 3 .

再例如，通过将第二中继光栅1022的光栅高度设置为不均等分布，使得第二中继光栅1022具有不均匀的衍射效率。例如，如图21所示，靠近耦出光栅103的一侧设置光栅高度较低，从而使得靠近耦出光栅103的一侧衍射效率较低；而设置靠近第一中继光栅1021的一侧光栅高度较高，从而保证靠近第一中继光栅1021的一侧衍射效率较高。可实施的，衍射效率也可以通过其他光栅参数进行调制，例如。可以调整光栅的占空比分布来调整光栅的衍射效率分布。For another example, by setting the grating heights of the second relay grating 1022 to be unevenly distributed, the second relay grating 1022 has uneven diffraction efficiency. For example, as shown in FIG. 21 , the grating height is lower on the side close to the outcoupling grating 103, so that the diffraction efficiency on the side close to the outcoupling grating 103 is low; while the grating on the side close to the first relay grating 1021 is set The height is higher, so as to ensure higher diffraction efficiency on the side close to the first relay grating 1021 . In practice, the diffraction efficiency can also be modulated by other grating parameters, eg. The duty ratio distribution of the grating can be adjusted to adjust the diffraction efficiency distribution of the grating.

可以理解，本申请实施例中，表面浮雕光栅可以为采用表面浮雕工艺在光波导表面形成光栅。通过设计表面浮雕光栅的相关参数，例如高度，可以对表面浮雕光栅的衍射效率进行调整。It can be understood that in the embodiment of the present application, the surface relief grating may be a grating formed on the surface of the optical waveguide by using a surface relief process. The diffraction efficiency of the surface relief grating can be adjusted by designing the relevant parameters of the surface relief grating, such as the height.

在另外一些实施例中，第一中继光栅1021和第二中继光栅1022可以均采用体全息光栅，其中，体全息光栅为通过双光束全息曝光的方式，直接在微米级厚度的体全息材料内部干涉形成明暗分布的干涉条纹形成；体全息光栅衍射效率可以通过体全息光栅的折射率调制度进行调控，光栅区域的折射率调制度越低，对应的光栅区域的衍射效率越低即光栅区域的折射率调制度与对应的光栅区域的衍射效率成正比。In some other embodiments, the first relay grating 1021 and the second relay grating 1022 can both use volume holographic gratings, wherein the volume holographic grating is a volume holographic material with a thickness of micron scale directly by means of double-beam holographic exposure. Internal interference forms interference fringes with bright and dark distribution; the diffraction efficiency of the volume holographic grating can be regulated by the refractive index modulation of the volume holographic grating, the lower the refractive index modulation of the grating area, the lower the diffraction efficiency of the corresponding grating area, that is, the grating area The degree of refractive index modulation is proportional to the diffraction efficiency of the corresponding grating area.

因此，若要使得第一中继光栅1021的衍射效率分布均匀分布，则可以设置第一中继光栅1021的折射率调制度均等分布。若要使得第二中继光栅1022具有不均匀的衍射效率，则可以设置第二中继光栅1022的折射率调制度不均等分布，具体的，可以为由远离耦出光栅103的区域向靠近耦出光栅103的区域折射率调制度逐渐降低。Therefore, if the diffraction efficiency distribution of the first relay grating 1021 is to be uniformly distributed, the refractive index modulation degree of the first relay grating 1021 may be uniformly distributed. To make the second relay grating 1022 have non-uniform diffraction efficiency, the refractive index modulation degree of the second relay grating 1022 can be set to be unevenly distributed. The degree of modulation of the regional refractive index of the grating 103 gradually decreases.

其中，体全息光栅的折射率调制度可以通过紫外曝光的时间进行调整，例如，紫外曝光的时间越长，折射率调制度越高。Wherein, the refractive index modulation degree of the volume holographic grating can be adjusted through the ultraviolet exposure time, for example, the longer the ultraviolet exposure time, the higher the refractive index modulation degree.

此外，在其他实施例中，第一中继光栅1021和第二中继光栅1022中的其中一个光栅区域可以采用表面浮雕光栅，另一个光栅区域可以采用体全息光栅，例如，第一中继光栅1021可以采用表面浮雕光栅，第二中继光栅1022可以采用体全息光栅。而具体衍射效率的调节可以参考前文所述的方法。In addition, in other embodiments, one of the grating regions of the first relay grating 1021 and the second relay grating 1022 can be a surface relief grating, and the other grating region can be a volume holographic grating, for example, the first relay grating 1021 may use a surface relief grating, and the second relay grating 1022 may use a volume holographic grating. For the adjustment of the specific diffraction efficiency, reference can be made to the method described above.

此外，可以理解，本申请实施例中，耦入光栅101的设置位置比较灵活。例如，可以如图17所示，将耦入光栅101设置在第一中继光栅1021和第二中继光栅1022之间的中继区域中，也可以如图22所示，设于第一中继光栅1021和第二中继光栅1022的延长区域之间，再或者，也可以如图23所示，将耦入光栅101设于第一中继光栅1021或第二中继光栅1022的任一侧。需要说明的是，本申请实施例中耦入光栅103的位置需要满足能够使得入射到耦入光栅103的光线能够被引导至第二中继光栅1023。In addition, it can be understood that in the embodiment of the present application, the setting position of the coupling-in grating 101 is relatively flexible. For example, as shown in FIG. 17, the coupling-in grating 101 can be set in the relay area between the first relay grating 1021 and the second relay grating 1022, or it can be set in the first relay grating 1022 as shown in FIG. between the extended area of the relay grating 1021 and the second relay grating 1022, or, as shown in FIG. side. It should be noted that the position of the in-coupling grating 103 in the embodiment of the present application needs to be such that the light incident on the in-coupling grating 103 can be guided to the second relay grating 1023 .

图24示出了一种采用图17所示的衍射光波导100作为镜片的AR眼镜200的结构示意图。如图24所示，AR眼镜200的左镜片201和右镜片201可以均采用图17所示的衍射光波导100。其中，图17中AR眼镜200的其他部分结构与图9中类似，在此不再赘述。FIG. 24 shows a schematic structural view of an AR glasses 200 using the diffractive optical waveguide 100 shown in FIG. 17 as a lens. As shown in FIG. 24 , the left lens 201 and the right lens 201 of the AR glasses 200 may both use the diffractive optical waveguide 100 shown in FIG. 17 . Wherein, other parts of the structure of the AR glasses 200 in FIG. 17 are similar to those in FIG. 9 , and will not be repeated here.

本申请实施例二中，衍射光波导100可以不仅限于包括上述两个中继光栅的实施方案，还可以包括三个及以上的中继光栅的实施方案。In Embodiment 2 of the present application, the diffractive optical waveguide 100 may not only be limited to the implementation including the above two relay gratings, but may also include three or more relay gratings.

可实施的，若衍射光波导100可以包括三个或三个以上的中继光栅，则每个中继光栅的周期和光栅矢量均相同；光线经耦入光栅的衍射可以传播至除第二中继光栅1022上。In practice, if the diffractive optical waveguide 100 can include three or more relay gratings, the period and grating vector of each relay grating are the same; Following the grating 1022 on.

在一些实施例中，包括多个中继光栅的实施方案中，距离耦出光栅距离最远的中继光栅的衍射效率要求与与上述包括两个光栅区域的实施方案中第一中继光栅1021的衍射效率要求相同，以使入射到该中继光栅上的光线能够全部被全反射至其他中继光栅。其余中继光栅的衍射效率要求与上述包括两个中继光栅的实施方案中第二中继光栅1022的衍射效率分布要求相同，以使入射到其余中继光栅上的光线能够部分被引导至第一中继光栅1021，另一部分被引导至耦出光栅103。In some embodiments, in an embodiment including multiple relay gratings, the diffraction efficiency requirement of the relay grating furthest from the outcoupling grating is the same as that of the first relay grating 1021 in the above embodiment including two grating regions. The diffraction efficiency requirements of the relay gratings are the same, so that the light incident on the relay grating can be totally reflected to other relay gratings. The requirements for the diffraction efficiency of the rest of the relay gratings are the same as the requirements for the distribution of the diffraction efficiency of the second relay grating 1022 in the above embodiment including two relay gratings, so that the rays incident on the rest of the relay gratings can be partially guided to the second relay grating. A relay grating 1021 , another part is directed to an outcoupling grating 103 .

例如，如图25所示，衍射光波导100的结构与图17中所示大致相同，其区别主要在于：第一中继光栅1021和第二中继光栅1022之间可以设有第三中继光栅1023。其中，第一中继光栅1021、第二中继光栅1022和第三中继光栅1023的周期和光栅矢量均相同；耦入光栅可以设于所述第三中继光栅1023上部、For example, as shown in FIG. 25, the structure of the diffractive optical waveguide 100 is roughly the same as that shown in FIG. Grating 1023. Wherein, the periods and grating vectors of the first relay grating 1021, the second relay grating 1022 and the third relay grating 1023 are the same; the coupling-in grating can be arranged on the third relay grating 1023 top,

可以理解，耦入光栅101与也可以设于其他能够使得光线被耦入光栅101引导至朝向第二中继光栅1022的方向进行传播的位置，例如，耦入光栅101也可以设于第二中继光栅1022和第三中继光栅1023之间。It can be understood that the coupling-in grating 101 can also be arranged at other positions that enable the light to be guided by the coupling-in grating 101 to propagate toward the direction of the second relay grating 1022, for example, the coupling-in grating 101 can also be located in the second relay grating 1022. between the relay grating 1022 and the third relay grating 1023 .

其中，第一中继光栅1021的衍射效率均匀分布，能够有效保证没有能量溢出中继区域。Wherein, the diffraction efficiency of the first relay grating 1021 is evenly distributed, which can effectively ensure that no energy overflows the relay area.

第二中继光栅1022可以具有不均匀的光栅效率，例如，靠近耦出光栅103的一侧衍射效率较低，靠近第三中继光栅1023的一侧衍射效率较高，从而有效保证有部分光线由第二中继光栅1022 耦入第三光栅区域1023，并保证有部分光线能够从第二光栅区域1022耦出进入耦出光栅103。The second relay grating 1022 may have non-uniform grating efficiency, for example, the diffraction efficiency is low on the side close to the outcoupling grating 103, and the diffraction efficiency is high on the side close to the third relay grating 1023, thereby effectively ensuring that some light The second relay grating 1022 is coupled into the third grating region 1023 , and it is ensured that part of the light can be coupled out from the second grating region 1022 into the outcoupling grating 103 .

第三中继光栅1023可以具有不均匀的光栅效率，例如，靠近第二中继光栅1022的一侧衍射效率较低，靠近第一中继光栅1021的一侧衍射效率较高，从而有效保证有部分光线由第三中继光栅1023耦入第二光栅区域1022，并保证有部分光线能够从第三光栅区域1023耦入第一中继光栅1021。The third relay grating 1023 may have non-uniform grating efficiency, for example, the diffraction efficiency is low on the side close to the second relay grating 1022, and the diffraction efficiency is high on the side close to the first relay grating 1021, thereby effectively ensuring that there is Part of the light is coupled into the second grating region 1022 by the third relay grating 1023 , and it is ensured that part of the light can be coupled into the first relay grating 1021 from the third grating region 1023 .

本申请实施例中，第一中继光栅1021和第二中继光栅1022之间均可以为表面浮雕光栅、体全息光栅等。In the embodiment of the present application, between the first relay grating 1021 and the second relay grating 1022 may be a surface relief grating, a volume holographic grating, or the like.

图26示出了光线在三个中继光栅的衍射光波导100中的导向示意图。Fig. 26 shows a schematic diagram of guiding light in the diffractive optical waveguide 100 of three relay gratings.

如图26所示，耦入光栅101将微型显示装置105投射的光线i1耦入波导衬底104中，并将光线i1引导至朝向第二中继光栅1022，如图中箭头B1所示；当光线沿箭头B2所示方向入射到第二中继光栅1022时，光线被分为两个部分，分别朝向不同的衍射角度传播。具体地，一部分光线在波导衬底104内部进行全反射传播，全反射传播的方向沿箭头B2所示方向入射到第三中继光栅1023，另一部分也在波导衬底104内部进行全反射传播，但全反射传播的方向沿箭头B3所示方向入射到耦出光栅103。As shown in FIG. 26, the coupling-in grating 101 couples the light i1 projected by the micro display device 105 into the waveguide substrate 104, and guides the light i1 towards the second relay grating 1022, as shown by the arrow B1 in the figure; When the light is incident on the second relay grating 1022 along the direction indicated by the arrow B2, the light is divided into two parts, which propagate towards different diffraction angles respectively. Specifically, a part of the light propagates through total reflection inside the waveguide substrate 104, and the direction of the total reflection propagation is incident on the third relay grating 1023 along the direction indicated by arrow B2, and the other part also undergoes total reflection propagation inside the waveguide substrate 104, However, the direction of total reflection propagation is incident to the outcoupling grating 103 along the direction indicated by arrow B3.

沿箭头B2所示方向入射到第三中继光栅1023的光线被分为两部分，分别朝向不同的衍射角度传播。具体地，一部分光线在波导衬底104内部进行全反射传播，全反射传播的方向沿箭头B4所示方向入射到第一中继光栅1021，另一部分也在波导衬底104内部进行全反射传播，全反射传播的方向沿箭头B5所示方向入射到第二中继光栅1022。The light incident on the third relay grating 1023 along the direction indicated by the arrow B2 is divided into two parts, which propagate towards different diffraction angles respectively. Specifically, a part of the light propagates through total reflection inside the waveguide substrate 104, and the direction of the total reflection propagation is incident on the first relay grating 1021 along the direction indicated by arrow B4, and another part also undergoes total reflection propagation inside the waveguide substrate 104, The propagation direction of the total reflection is incident on the second relay grating 1022 along the direction indicated by arrow B5.

沿箭头B4所示方向入射到第一中继光栅1021的光线沿箭头B6所示方向入射到第三中继光栅1023，入射到第三中继光栅1023的光线重复上述过程。The light incident on the first relay grating 1021 along the direction indicated by the arrow B4 enters the third relay grating 1023 along the direction indicated by the arrow B6, and the light incident on the third relay grating 1023 repeats the above process.

其光线在衍射光波导100中的具体光路示意图如图19中类似，均为按照引导方向在波导衬底104的上下表面间全反射传播，在此不再赘述。The specific schematic diagram of the optical path of the light in the diffractive optical waveguide 100 is similar to that shown in FIG. 19 , which is totally reflected and propagated between the upper and lower surfaces of the waveguide substrate 104 according to the guiding direction, and will not be repeated here.

本申请实施例中，中继光栅102也可以由在中继区域产生的间断分布的折射率调制区域形成。例如，通过紫外光照射波导衬底104在中继区域产生间断分布的不同折射率调制度的区域。具体的，可以通过调整紫外光曝光的时间调整各个区域的折射率调制度，以使得中继光栅102的各区域的折射率调制度不同。In the embodiment of the present application, the relay grating 102 may also be formed by discontinuously distributed refractive index modulation regions generated in the relay region. For example, irradiating the waveguide substrate 104 with ultraviolet light produces discontinuously distributed regions of different refractive index modulation degrees in the relay region. Specifically, the refractive index modulation degree of each region can be adjusted by adjusting the ultraviolet light exposure time, so that the refractive index modulation degree of each region of the relay grating 102 is different.

在一些实施例中，以中继区域包括三个光栅区域为例，图27示出了衍射光波导在y负半轴方向上设置的三个折射率调制度不同的中继光栅，第一中继光栅1021和第二中继光栅1022和第三中继光栅1023。其中，第一中继光栅1021、第二中继光栅1022和第三中继光栅1023的周期和光栅矢量均相同；耦入光栅设于中继区域的表面，例如可以位于所述第三中继光栅1023位置的表面。In some embodiments, taking the relay region including three grating regions as an example, FIG. 27 shows three relay gratings with different refractive index modulation degrees arranged in the diffractive optical waveguide in the direction of the negative half-axis of y. A relay grating 1021, a second relay grating 1022, and a third relay grating 1023. Wherein, the periods and grating vectors of the first relay grating 1021, the second relay grating 1022 and the third relay grating 1023 are the same; The grating 1023 is positioned on the surface.

其中，图27中第一中继光栅1021、第二光中继光栅1022、第三中继光栅1023的衍射效率分布及光线的引导方向等均与图26中相同。Wherein, the diffraction efficiency distribution of the first relay grating 1021 , the second optical relay grating 1022 , and the third relay grating 1023 in FIG. 27 and the guiding direction of light are the same as those in FIG. 26 .

本申请实施例三中，与前面所描述的结构不同，衍射光波导100也可以如图28所示，包括两层波导层。例如，可以把下层的波导层定义为波导衬底104，上层的波导层定义为波导顶层106，即衍射光波导100可以包括波导衬底104和波导顶层107。其中，波导衬底104和波导顶层107之间可以夹设有光栅层，光栅层可以形成有包括上述实施方案中提及的任何耦入光栅101、多个中继光栅(如第一中继光栅1021和第二中继光栅1022)及耦出光栅103的排布方式，其中，In Embodiment 3 of the present application, different from the structure described above, the diffractive optical waveguide 100 may also include two waveguide layers as shown in FIG. 28 . For example, the lower waveguide layer can be defined as the waveguide substrate 104 , and the upper waveguide layer can be defined as the waveguide top layer 106 , that is, the diffractive optical waveguide 100 can include the waveguide substrate 104 and the waveguide top layer 107 . Wherein, a grating layer may be interposed between the waveguide substrate 104 and the waveguide top layer 107, and the grating layer may be formed with any coupling-in grating 101 mentioned in the above embodiments, a plurality of relay gratings (such as the first relay grating 1021 and the second relay grating 1022) and the arrangement of the outcoupling grating 103, wherein,

光栅层可以为通过在波导衬底104和波导顶层107之间设置全息材料层108，通过全息曝光技术在全息材料层108产生上述实施方案中提及的任何耦入光栅101、多个中继光栅(如第一中继光栅1021和第二中继光栅1022)及耦出光栅103的排布方式。The grating layer can be a holographic material layer 108 disposed between the waveguide substrate 104 and the waveguide top layer 107, and any coupling grating 101 and multiple relay gratings mentioned in the above embodiments are produced on the holographic material layer 108 by holographic exposure technology. (such as the first relay grating 1021 and the second relay grating 1022 ) and the arrangement of the outcoupling grating 103 .

可以理解，光栅层的上述实施方案中提及的任何耦入光栅101、多个中继光栅(如第一中继光栅1021和第二中继光栅1022)及耦出光栅103也可以为表面浮雕光栅等其他方式形成的光栅。对应的光线传播的方式与上述实施方案中相同，此处不再赘述。It can be understood that any of the incoupling grating 101, multiple relay gratings (such as the first relay grating 1021 and the second relay grating 1022) and the outcoupling grating 103 mentioned in the above embodiments of the grating layer can also be surface relief Gratings formed by other methods such as gratings. The corresponding way of light propagation is the same as that in the above embodiment, and will not be repeated here.

本申请实施例中，两层波导层夹着全息材料层可以保证全息材料层的厚度均匀，增加光线传播的稳定性。在一些实施例中，也可以直接将全息材料涂在波导层的其中一表面，例如，可以波导衬底104的上表面或波导顶层107的下表面上，通过全息曝光技术在全息材料上产生上述实施方案中提及的任何耦入光栅101、多个中继光栅(如第一中继光栅1021和第二中继光栅1022)及耦出光栅103的排布方式。In the embodiment of the present application, the holographic material layer is sandwiched between two waveguide layers to ensure uniform thickness of the holographic material layer and increase the stability of light propagation. In some embodiments, the holographic material can also be directly coated on one of the surfaces of the waveguide layer, for example, on the upper surface of the waveguide substrate 104 or the lower surface of the waveguide top layer 107, the above-mentioned Any arrangement of the in-coupling grating 101 , multiple relay gratings (such as the first relay grating 1021 and the second relay grating 1022 ) and the out-coupling grating 103 mentioned in the embodiments.

在另一些实施例中，衍射光波导也可以包括多个波导衬底104和位于每个波导衬底104上的光栅层，多个波导衬底104在z轴方向层叠连接。该方案可以采用每个波导衬底104只传播一种或多种波长不同的单色光，该方案能够减少***颜色的串扰，从而可以改善最终在出瞳位置的颜色均匀性。例如，微型显示装置105投射出的是红光、蓝光和绿光三种单色光，可以在上述波导衬底104和波导顶层107之间设置光栅层方案的基础上，在波导顶层107的上表面或波导底层104的下表面也增加光栅层，通过波导顶层107传播绿光，通过波导衬底104传播红光和蓝光。再例如，可以将三个上述实施方案中提及的衍射光波导100在z轴方向层叠连接，每一个衍射光波导100传播其中一种单色光，最终共同耦入人眼。In some other embodiments, the diffractive optical waveguide may also include multiple waveguide substrates 104 and a grating layer on each waveguide substrate 104, and the multiple waveguide substrates 104 are stacked and connected in the z-axis direction. In this solution, each waveguide substrate 104 can transmit only one or more monochromatic lights with different wavelengths. This solution can reduce the crosstalk of system colors, thereby improving the final color uniformity at the exit pupil position. For example, the microdisplay device 105 projects three monochromatic lights: red light, blue light and green light. On the basis of the grating layer solution between the above-mentioned waveguide substrate 104 and the waveguide top layer 107, on the waveguide top layer 107 A grating layer is also added to the surface or lower surface of the waveguide bottom layer 104 to transmit green light through the waveguide top layer 107 and red and blue light through the waveguide substrate 104 . For another example, the three diffractive optical waveguides 100 mentioned in the above embodiments may be stacked and connected in the z-axis direction, and each diffractive optical waveguide 100 propagates one of the monochromatic lights, and finally couples them into the human eye.

可以理解，在本申请的各实施例中，通过在光波导衬底的表面上设置各类光栅来实现光线的引导作用，而在其他实施例中，也可以采用具有光栅衍射功能的其他光学元件来实现上述技术方案。此外，这些光学元件，也可以不设置在光波导衬底的表面上，而是设置在光波导衬底内部来实现光线的引导作用，例如，通过使得光波导衬底中某一区域内的微观结构发生变化，使得该区域的微观分子结构能够实现耦入光栅101、第一中继光栅1021、第二中继光栅1022、或者耦出光栅103的功能。It can be understood that in each embodiment of the present application, the guiding function of light is realized by setting various types of gratings on the surface of the optical waveguide substrate, and in other embodiments, other optical elements with grating diffraction function can also be used To realize the above-mentioned technical scheme. In addition, these optical elements may not be arranged on the surface of the optical waveguide substrate, but arranged inside the optical waveguide substrate to realize the guiding function of light, for example, by making the microscopic The structure changes, so that the microscopic molecular structure of this region can realize the function of coupling in the grating 101 , the first relay grating 1021 , the second relay grating 1022 , or the coupling out of the grating 103 .

本申请上述实施例上述提供的中继光栅102可以包括多个折射率不同的中继光栅的技术方案，能够使得光线在多个中继光栅内通过往复传播实现光线的出瞳扩展，而无需随着视场角的增大而增大中继光栅的面积，使得衍射光波导100能够应用于大视场角的各种设备中。The relay grating 102 provided above in the above embodiments of the present application may include a technical solution of multiple relay gratings with different refractive indices, which enables the light to expand the exit pupil of the light through reciprocating propagation in multiple relay gratings without The area of the relay grating increases with the increase of the viewing angle, so that the diffractive optical waveguide 100 can be applied to various devices with a large viewing angle.

下面根据本申请一些实施例，介绍上述衍射光波导100上各光栅的尺寸的设定方法。The method for setting the size of each grating on the diffractive optical waveguide 100 will be introduced below according to some embodiments of the present application.

(1)耦入光栅101的尺寸确定(1) Determination of the size of the coupling-in grating 101

本申请实施例中，耦入光栅101的尺寸可以是如27中所示为方形，可实施的，也可以根据实际需求设置为其他形状,例如为圆形等。In the embodiment of the present application, the size of the coupling-in grating 101 may be a square as shown in 27, which is practical, and may also be set to other shapes according to actual needs, such as a circle.

耦入光栅101的尺寸要大于等于所用微型显示装置105的出瞳尺寸。例如若出瞳尺寸为直径4mm，耦入光栅101的形状为圆形，则耦入光栅101的的尺寸至少为直径4mm；若耦入光栅101的形状为方形，则耦入光栅101的尺寸至少为4*4mm。可实施的，耦入光栅101的尺寸可以根据AR眼镜的尺寸等进行调整，例如，根据一般AR眼镜的尺寸，耦入光栅101的尺寸可以设置为0.5*0.5mm至10*10mm之间。The size of the coupling-in grating 101 should be greater than or equal to the size of the exit pupil of the micro-display device 105 used. For example, if the exit pupil size is 4 mm in diameter and the shape of the coupling-in grating 101 is circular, then the size of the coupling-in grating 101 is at least 4 mm in diameter; if the shape of the coupling-in grating 101 is square, the size of the coupling-in grating 101 is at least It is 4*4mm. In practice, the size of the coupling-in grating 101 can be adjusted according to the size of the AR glasses. For example, according to the size of general AR glasses, the size of the coupling-in grating 101 can be set between 0.5*0.5mm and 10*10mm.

(2)第一中继光栅和第二中继光栅的尺寸确定(2) Size determination of the first relay grating and the second relay grating

第一中继光栅1021及第二中继光栅1022之间的间隔大于等于耦入光栅101在y方向上的尺寸值。可实施的，第一中继光栅1021及第二中继光栅1022在y方向上的宽度尺寸也可以根据AR眼镜的尺寸等进行调整，例如，根据一般AR眼镜的尺寸，第一中继光栅1021及第二中继光栅1022 在y方向上的宽度尺寸可以为0.1-10mm之间。The distance between the first relay grating 1021 and the second relay grating 1022 is greater than or equal to the dimension value of the coupling-in grating 101 in the y direction. In practice, the width of the first relay grating 1021 and the second relay grating 1022 in the y direction can also be adjusted according to the size of the AR glasses. For example, according to the size of the general AR glasses, the first relay grating 1021 And the width of the second relay grating 1022 in the y direction may be between 0.1 mm and 10 mm.

(3)耦出光栅的尺寸确定(3) Determination of the size of the outcoupling grating

耦出光栅101的尺寸要大于等于光线在波导衬底104中的最终出瞳尺寸。例如，最终出瞳尺寸为4*4mm，则耦出光栅101的尺寸可以为5*5mm等，以满足光线的出瞳需求。The size of the outcoupling grating 101 should be greater than or equal to the final exit pupil size of the light in the waveguide substrate 104 . For example, if the final exit pupil size is 4*4mm, the size of the outcoupling grating 101 may be 5*5mm to meet the exit pupil requirement of the light.

本申请实施例中，耦入光栅101的周期也需要满足设定条件，如下所述：In the embodiment of the present application, the period coupled into the grating 101 also needs to meet the set conditions, as follows:

假设增强现实显示器的FOV对应的水平视场和竖直视场分别为FOV _hor及FOV _ver，在该视场范围内，某一视场的光线可以用(θ _hor,θ _ver)来表示，并且有θ _hor∈FOV _hor及θ _ver∈FOV _ver； Assuming that the horizontal field of view and vertical field of view corresponding to the FOV of the augmented reality display are FOV _hor and FOV _ver respectively, within the range of the field of view, the light of a certain field of view can be represented by (θ _hor , θ _ver ), and There are θ _hor ∈ FOV _hor and θ _ver ∈ FOV _ver ;

对于耦入光栅101，m级次所对应的衍射光的极角θ _m需要满足设定条件才能使耦入进波导衬底104的光线能够在波导衬底104中进行全反射传播，其设定条件为： For the coupling into the grating 101, the polar angle θ _m of the diffracted light corresponding to the m order needs to meet the set conditions so that the light coupled into the waveguide substrate 104 can be transmitted through the total reflection in the waveguide substrate 104, and the setting The conditions are:

为了使得通过耦入光栅101的光线能够满足设定角度的衍射，例如m级次的衍射，如前文表达式(1)所示，耦入光栅101的周期d需要满足的设定条件为：In order to make the light coupled into the grating 101 satisfy the diffraction at a set angle, such as the m-order diffraction, as shown in the above expression (1), the setting condition that the period d of the coupled into the grating 101 needs to satisfy is:

其中，m为衍射级次，n为波导衬底104的折射率，θ _m及

为m级次所对应的衍射光的极角及方位角，λ为入射光波长，θ及

分别为入射光的极角及方位角，θ _Gin为衍射光栅的刻痕的角度。其中，θ及

的计算过程如下： Wherein, m is the diffraction order, n is the refractive index of the waveguide substrate 104, θ _m and

is the polar angle and azimuth angle of diffracted light corresponding to order m, λ is the wavelength of incident light, θ and

are the polar angle and azimuth angle of the incident light respectively, and θ _Gin is the angle of the notch of the diffraction grating. Among them, θ and

The calculation process is as follows:

例如，若某一视场的光线为(45°，45°)，即入射光的极角θ及及方位角

均为45°，且入射光的波长为650nm,衍射级次m为1，衍射光栅的刻痕的角度为45度°，且选择的波导衬底结构104的折射率为2，m级次所对应的衍射光的极角和方位角均为45度，则计算得出耦入光栅101的周期d为248nm。 For example, if the light of a certain field of view is (45°, 45°), that is, the polar angle θ and azimuth angle of the incident light

are all 45°, and the wavelength of the incident light is 650nm, the diffraction order m is 1, the angle of the notch of the diffraction grating is 45°, and the refractive index of the selected waveguide substrate structure 104 is 2, the order m is The polar angle and azimuth angle of the corresponding diffracted light are both 45 degrees, and the period d coupled into the grating 101 is calculated to be 248 nm.

在一些实施例中，根据对通过耦入光栅101的光线所需的衍射角度需求，可以调整耦入光栅的周期，例如，耦入光栅的周期范围可以为200nm-500nm。In some embodiments, the period of the in-coupling grating can be adjusted according to the diffraction angle requirement of the light passing through the in-coupling grating 101 , for example, the period of the in-coupling grating can range from 200 nm to 500 nm.

下面以k空间中光线在图17所示的衍射光波导100的传播为例说明保证耦出光栅103的光栅矢量与耦入光栅101相同，并且第一中继光栅1021与第二中继光栅1022的光栅矢量相同，能够使得耦出光线的k空间区域与入射光完全重合，有效防止图像畸变的产生的具体原因。如下所述：Taking the propagation of light in the k-space in the diffractive optical waveguide 100 shown in FIG. The same grating vector can make the k-space area of outcoupling light completely coincide with the incident light, effectively preventing the specific cause of image distortion. As described below:

假设入射光对应的k空间矢量为：Suppose the k-space vector corresponding to the incident light is:

则耦入光栅101对入射光的衍射可以表示为Then the diffraction of the incident light by the coupling-in grating 101 can be expressed as

即which is

其中，

为衍射光k矢量，

为入射光k矢量，

为光栅k矢量，并且 in,

is the diffracted light k vector,

is the incident light k vector,

is a raster k-vector, and

对于图17所示的衍射光波导100，其k空间路径如图29所示，中心区域方块表示入射光的视场所对应的k空间区域。例如，经过耦入光栅101之后，在第一中继光栅1021及第二中继光栅1022的多次反射作用下，在衍射光100内往复传播的k空间区域为图14中左下角方块表示的区域和左上角方块表示的区域，在第一中继光栅1021及第二中继光栅1022的多次反射作用后，k空间区域重新回到图29中左下角方块表示的区域，然后入射到耦出光栅103时，耦出光栅103可以将光线耦出波导，其中，耦出光线的k空间区域与入射光的k空间区域完全重合，能够有效防止图像畸变的产生。For the diffractive optical waveguide 100 shown in FIG. 17 , its k-space path is shown in FIG. 29 , and the square in the central area represents the k-space area corresponding to the field of view of the incident light. For example, after being coupled into the grating 101, under the multiple reflections of the first relay grating 1021 and the second relay grating 1022, the k-space region that reciprocates in the diffracted light 100 is represented by the square in the lower left corner of Fig. 14 area and the area indicated by the square in the upper left corner, after the multiple reflections of the first relay grating 1021 and the second relay grating 1022, the k-space area returns to the area indicated by the square in the lower left corner in Figure 29, and then enters the coupling When exiting the grating 103, the outcoupling grating 103 can couple the light out of the waveguide, wherein the k-space region of the outcoupling light completely overlaps with the k-space region of the incident light, which can effectively prevent image distortion.

例如，设耦入光栅101的K矢量为For example, let the K vector coupled into the grating 101 be

设耦出光栅103的K矢量为Let the K vector out of the grating 103 be

设第一中继光栅1021和第二中继光栅1022的K矢量分别为Let the K vectors of the first relay grating 1021 and the second relay grating 1022 be respectively

因为耦入光栅101与耦出光栅103的K矢量相同，且第一中继光栅1021和第二中继光栅1022的K矢量相同，所以Because the K vectors of the coupling-in grating 101 and the coupling-out grating 103 are the same, and the K vectors of the first relay grating 1021 and the second relay grating 1022 are the same, so

通过上式可以表明进入波导的光线，经过波导结构中耦入光栅101、第一中继光栅1021、第二中继光栅1022及耦出光栅103的多次作用，再次射出波导结构时，光线的方向不会发生变化，从而保证了图像不会存在畸变。Through the above formula, it can be shown that the light entering the waveguide passes through the multiple actions of the coupling-in grating 101, the first relay grating 1021, the second relay grating 1022 and the out-coupling grating 103 in the waveguide structure, and when it exits the waveguide structure again, the The orientation will not change, thus ensuring that the image will not be distorted.

并且因为耦入光栅101与耦出光栅103的K矢量相同，且第一中继光栅1021和第二中继光栅1022的K矢量相同，即And because the K vectors of the coupling-in grating 101 and the coupling-out grating 103 are the same, and the K vectors of the first relay grating 1021 and the second relay grating 1022 are the same, that is

因此：therefore:

其中N表示光线在第一中继光栅1021和第二中继光栅1022之间进行多次往复传播的次数，从上式可以看出，因为

所以不论N的值为多少，

均等于0，所以光线在第一中继光栅1021和第二光栅那区域间多次往复传播也不会引入额外的相位差，能保证光线在进入第一中继光栅1021时的方向和从第一光栅衍射出的传播方向一致。 Among them, N represents the number of times that light travels back and forth between the first relay grating 1021 and the second relay grating 1022, as can be seen from the above formula, because

So no matter what the value of N is,

are equal to 0, so the light will not introduce additional phase difference when it travels back and forth between the first relay grating 1021 and the second grating area, which can ensure the direction of the light when it enters the first relay grating 1021 and from the second grating The direction of propagation diffracted by a grating is consistent.

综上，本申请实施例提供的耦出光栅103与耦入光栅101的周期和光栅矢量方向一致，中继光栅102的第一中继光栅1021和第二中继光栅1022的周期和光栅矢量方向也一致的技术方案，能够使得进入波导结构的光线，经过波导结构中耦入光栅101、第一中继光栅1021、第二中继光栅1022及耦出光栅103的多次作用，再次射出波导结构时，光线的方向不会发生变化，从而保证了图像不会存在畸变。In summary, the outcoupling grating 103 provided by the embodiment of the present application is consistent with the period and grating vector direction of the incoupling grating 101, and the period and grating vector direction of the first relay grating 1021 and the second relay grating 1022 of the relay grating 102 are consistent. The same technical solution can make the light entering the waveguide structure go out of the waveguide structure again through multiple actions of the in-coupling grating 101, the first relay grating 1021, the second relay grating 1022 and the out-coupling grating 103 in the waveguide structure When , the direction of the light will not change, thus ensuring that the image will not be distorted.

需要说明的是，本申请实施例提供的光栅波导结构除了应用于上述AR眼镜200中，也可以应用于其他领域，例如可以应用于车载平视显示器(Head Up Display，HUD)中，通过本申请实施例提供的衍射光波导100将重要的行车数据或图像投射到前挡玻璃上，方便驾驶员查看，提升驾驶安全。It should be noted that the grating waveguide structure provided in the embodiment of this application can be applied to other fields besides the above-mentioned AR glasses 200, for example, it can be applied to a vehicle head-up display (Head Up Display, HUD). The diffractive optical waveguide 100 provided in the example projects important driving data or images onto the windshield, which is convenient for the driver to view and improves driving safety.

显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的精神和范围。这样，倘若本申请的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。Obviously, those skilled in the art can make various changes and modifications to the application without departing from the spirit and scope of the application. In this way, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application is also intended to include these modifications and variations.

Claims

一种光学设备，其特征在于，包括至少一个波导衬底，以及设置于所述波导衬底上的耦入单元、第一中继单元、第二中继单元、以及耦出单元；An optical device, characterized by comprising at least one waveguide substrate, and an in-coupling unit, a first relay unit, a second relay unit, and an out-coupling unit disposed on the waveguide substrate;

所述耦入单元被配置为将光线耦入所述波导衬底中；The coupling unit is configured to couple light into the waveguide substrate;

所述第一中继单元和第二中继单元限定出中继区域，所述中继区域在第一方向延伸，所述第一中继单元和第二中继单元在第二方向排列，所述中继区域在所述第二方向上具有相对的第一边和第二边，所述第一边的延伸方向与所述第二边的延伸方向之间夹角小于第一角度；The first relay unit and the second relay unit define a relay area, the relay area extends in a first direction, the first relay unit and the second relay unit are arranged in a second direction, the The relay area has a first side and a second side opposite to each other in the second direction, and the angle between the extension direction of the first side and the extension direction of the second side is smaller than the first angle;

所述耦出单元被配置为将所述波导衬底中的光线耦出所述波导衬底，所述耦出单元与所述中继区域在所述第二方向排列。The outcoupling unit is configured to couple light in the waveguide substrate out of the waveguide substrate, and the outcoupling unit and the relay region are arranged in the second direction.
根据权利要求1所述的光学设备，其特征在于，所述第一角度在0°～5°。The optical device according to claim 1, wherein the first angle is between 0°-5°.
根据权利要求1所述的光学设备，其特征在于，所述第一边和所述第二边在延伸方向平行。The optical device according to claim 1, wherein the first side and the second side are parallel in an extending direction.
根据权利要求1所述的光学设备，其特征在于，所述第二中继单元被配置为使得所述波导衬底中进行全反射传播的光线在入射到所述第二中继单元后至少部分出射光线朝着所述第一中继单元进行全反射传播，至少部分出射光线朝着所述耦出单元进行全反射传播；The optical device according to claim 1, wherein the second relay unit is configured such that the light propagating through total reflection in the waveguide substrate is at least partly incident on the second relay unit The outgoing light propagates toward the first relay unit through total reflection, and at least part of the outgoing light propagates toward the outcoupling unit through total reflection;

所述第一中继单元被配置为使得所述波导衬底中全反射传播的光线在入射到所述第一中继单元后出射光线朝着所述第二中继单元进行全反射传播。The first relay unit is configured such that the light propagated through total reflection in the waveguide substrate is incident on the first relay unit, and then the outgoing light propagates toward the second relay unit through total reflection.
根据权利要求1所述的光学设备，其特征在于，所述第一中继单元和第二中继单元为光栅；并且The optical device according to claim 1, wherein the first relay unit and the second relay unit are gratings; and

所述中继区域的第一边为所述第一中继单元最靠近所述第二中继单元的栅线，第二边为所述第二中继单元最靠近所述第一中继单元的栅线；The first side of the relay area is the gate line of the first relay unit closest to the second relay unit, and the second side is the gate line of the second relay unit closest to the first relay unit grid line;

或者，or,

所述中继区域的第一边为所述第一中继单元最远离所述第二中继单元的栅线，第二边为所述第二中继单元最远离所述第一中继单元的栅线。The first side of the relay area is the gate line that the first relay unit is farthest from the second relay unit, and the second side is the gate line that the second relay unit is farthest from the first relay unit grid line.
根据权利要求5所述的光学设备，其特征在于，所述第一中继单元和第二中继单元均包括多条光栅栅线，并且所述第一中继单元和第二中继单元的光栅栅线相互呈所述第一角度。The optical device according to claim 5, wherein the first relay unit and the second relay unit each comprise a plurality of grating lines, and the first relay unit and the second relay unit The grating lines are at the first angle to each other.
根据权利要求6所述的光学设备，其特征在于，所述第一中继单元和第二中继单元均包括多条光栅栅线，并且所述第一中继单元和第二中继单元的光栅栅线相互平行。The optical device according to claim 6, wherein the first relay unit and the second relay unit each comprise a plurality of grating lines, and the first relay unit and the second relay unit The grating lines are parallel to each other.
根据权利要求5所述的光学设备，其特征在于，所述第一中继单元和第二中继单元为相互平行的条形光栅。The optical device according to claim 5, wherein the first relay unit and the second relay unit are bar gratings parallel to each other.
根据权利要求5所述的光学设备，其特征在于，所述第一中继单元与所述第二中继单元的光栅周期相同。The optical device according to claim 5, wherein the grating period of the first relay unit is the same as that of the second relay unit.
根据权利要求5所述的光学设备，其特征在于，所述第一中继单元的衍射效率均等分布，所述第二中继单元的衍射效率由远离所述耦出单元的一侧至靠近所述耦出单元的一侧逐渐降低。The optical device according to claim 5, wherein the diffraction efficiency of the first relay unit is equally distributed, and the diffraction efficiency of the second relay unit is from a side far away from the outcoupling unit to a side close to the outcoupling unit. The side of the outcoupling unit tapers down.
根据权利要求10所述的光学设备，其特征在于，所述第一中继单元为表面浮雕光栅，并且所述第一中继单元的光栅高度均等分布。The optical device according to claim 10, wherein the first relay unit is a surface relief grating, and the grating heights of the first relay unit are evenly distributed.
根据权利要求10所述的光学设备，其特征在于，所述第二中继单元为表面浮雕光栅，并且所述第二中继单元的光栅高度由远离所述耦出单元的一侧至靠近所述耦出单元的一侧逐渐降低。The optical device according to claim 10, wherein the second relay unit is a surface relief grating, and the height of the grating of the second relay unit is from a side far away from the outcoupling unit to a side close to the outcoupling unit. The side of the outcoupling unit tapers down.
根据权利要求10所述的光学设备，其特征在于，所述第一中继单元为体全息光栅，并且所述第一中继单元的折射率调制度均等分布。The optical device according to claim 10, wherein the first relay unit is a volume holographic grating, and the refractive index modulation of the first relay unit is equally distributed.
根据权利要求10所述的光学设备，其特征在于，所述第二中继单元为体全息光栅，并且所述第二中继单元的光栅折射率调制度由远离所述耦出单元的一侧至靠近所述耦出单元的一侧逐渐降低。The optical device according to claim 10, wherein the second relay unit is a volume holographic grating, and the modulation degree of the grating refractive index of the second relay unit is from the side far away from the outcoupling unit It gradually decreases to the side close to the outcoupling unit.
根据权利要求1所述的光学设备，其特征在于，还包括设置于所述波导衬底上的至少一个第三中继单元，所述第三中继单元设位于所述第一中继单元与所述第二中继单元之间，并且The optical device according to claim 1, further comprising at least one third relay unit disposed on the waveguide substrate, the third relay unit being located between the first relay unit and between the second relay unit, and

所述第三中继单元将所述中继区域划分为多个中继子区域，并且所述中继子区域的两条长边在延伸方向的夹角小于所述第一角度。The third relay unit divides the relay area into a plurality of relay sub-areas, and an angle between two long sides of the relay sub-area in an extending direction is smaller than the first angle.
根据权利要求15所述的光学设备，其特征在于，The optical device according to claim 15, characterized in that,

所述第三中继单元被配置为：使得所述波导衬底中进行全反射传播的光线入射到所述第三中继单元后，至少部分出射光线朝着所述第一中继单元进行全反射传播，至少部分出射光线朝着所述第二中继单元进行全反射传播。The third relay unit is configured such that after the light propagating through total reflection in the waveguide substrate is incident on the third relay unit, at least part of the outgoing light is fully reflected toward the first relay unit. Reflective propagation, at least part of the outgoing light is propagated toward the second relay unit through total reflection.
根据权利要求15所述的光学设备，其特征在于，所述第一中继单元、第二中继单元、以及所述第三中继单元为光栅。The optical device according to claim 15, wherein the first relay unit, the second relay unit, and the third relay unit are gratings.
根据权利要求17所述的光学设备，其特征在于，所述第一中继单元、第二中继单元、以及所述第三中继单元均包括多条相互平行的栅线。The optical device according to claim 17, wherein the first relay unit, the second relay unit, and the third relay unit each comprise a plurality of grid lines parallel to each other.
根据权利要求15所述的光学设备，其特征在于，所述第三中继单元为条形光栅。The optical device according to claim 15, wherein the third relay unit is a bar grating.
根据权利要求17所述的光学设备，其特征在于，所述第三中继单元的衍射效率由靠近所述第一中继单元的一侧至靠近所述第二中继单元的一侧逐渐降低。The optical device according to claim 17, wherein the diffraction efficiency of the third relay unit gradually decreases from a side close to the first relay unit to a side close to the second relay unit .
根据权利要求20所述的光学设备，其特征在于，所述第三中继单元为表面浮雕光栅，并且所述第三中继单元的光栅高度由靠近所述第一中继单元的一侧至靠近所述第二中继单元的一侧逐渐降低。The optical device according to claim 20, wherein the third relay unit is a surface relief grating, and the height of the grating of the third relay unit is from the side close to the first relay unit to The side close to the second relay unit is gradually lowered.
根据权利要求20所述的光学设备，其特征在于，所述第三中继单元为体全息光栅，并且所述第三中继单元的光栅折射率调制度由靠近所述第一中继单元的一侧至靠近所述第二中继单元的一侧逐渐降低。The optical device according to claim 20, wherein the third relay unit is a volume holographic grating, and the grating refractive index modulation degree of the third relay unit is determined by gradually decrease from one side to the side close to the second relay unit.
根据权利要求1所述的光学设备，其特征在于，所述耦入单元位于所述中继区域中。The optical device according to claim 1, characterized in that the coupling-in unit is located in the relay area.
根据权利要求1所述的光学设备，其特征在于，所述耦入单元和耦出单元为光栅，并且所述耦入单元与所述耦出单元的周期和光栅矢量方向均相同。The optical device according to claim 1, wherein the coupling-in unit and the out-coupling unit are gratings, and the periods and grating vector directions of the coupling-in unit and the out-coupling unit are the same.
根据权利要求1所述的光学设备，其特征在于，所述耦入单元为表面浮雕光栅或者体全息光栅；并且The optical device according to claim 1, wherein the coupling unit is a surface relief grating or a volume holographic grating; and

所述耦出单元为表面浮雕光栅或者体全息光栅。The outcoupling unit is a surface relief grating or a volume holographic grating.
根据权利要求1所述的光学设备，其特征在于，所述耦入单元、第一中继单元、第二中继单元、以及耦出单元位于所述波导衬底的至少一个底面上。The optical device according to claim 1, wherein the coupling-in unit, the first relay unit, the second relay unit, and the out-coupling unit are located on at least one bottom surface of the waveguide substrate.
根据权利要求1所述的光学设备，其特征在于，还包括全息材料层，并且所述波导衬底的数量为两个，所述全息材料层夹于两个所述波导衬底之间；The optical device according to claim 1, further comprising a holographic material layer, and the number of the waveguide substrates is two, and the holographic material layer is sandwiched between the two waveguide substrates;

所述耦入单元、第一中继单元、第二中继单元、以及耦出单元位于所述全息材料层的至少一个底面上。The incoupling unit, the first relay unit, the second relay unit, and the outcoupling unit are located on at least one bottom surface of the holographic material layer.
一种电子设备，其特征在于，包括微型显示装置和权利要求1至27中任一项所述的光学设备，并且所述微型显示装置用于向所述光学设备的耦入单元投射光线。An electronic device, characterized by comprising a micro display device and the optical device according to any one of claims 1 to 27, and the micro display device is used for projecting light to the coupling unit of the optical device.
根据权利要求28所述的电子设备，其特征在于，所述电子设备为增强现实眼镜。The electronic device according to claim 28, wherein the electronic device is augmented reality glasses.
根据权利要求28所述的电子设备，其特征在于，所述电子设备为车载平视显示器。The electronic device according to claim 28, wherein the electronic device is a vehicle-mounted head-up display.