WO2022178987A1 - 一种光学系统及混合现实设备 - Google Patents

一种光学系统及混合现实设备 Download PDF

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Publication number
WO2022178987A1
WO2022178987A1 PCT/CN2021/094734 CN2021094734W WO2022178987A1 WO 2022178987 A1 WO2022178987 A1 WO 2022178987A1 CN 2021094734 W CN2021094734 W CN 2021094734W WO 2022178987 A1 WO2022178987 A1 WO 2022178987A1
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Prior art keywords
image light
diffraction grating
optical system
base layer
layer
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PCT/CN2021/094734
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English (en)
French (fr)
Inventor
袁俊旗
马玉胜
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南昌三极光电有限公司
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Publication of WO2022178987A1 publication Critical patent/WO2022178987A1/zh

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
    • G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
    • G02B30/34—Stereoscopes providing a stereoscopic pair of separated images corresponding to parallactically displaced views of the same object, e.g. 3D slide viewers
    • G02B30/35—Stereoscopes providing a stereoscopic pair of separated images corresponding to parallactically displaced views of the same object, e.g. 3D slide viewers using reflective optical elements in the optical path between the images and the observer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/0081—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for altering, e.g. enlarging, the entrance or exit pupil
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G02B27/0103—Head-up displays characterised by optical features comprising holographic elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/017—Head mounted
    • G02B27/0172—Head mounted characterised by optical features
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G02B27/1086—Beam splitting or combining systems operating by diffraction only
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/42—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect
    • G02B27/4205—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
    • G02B27/4227—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant in image scanning systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/42—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect
    • G02B27/4272—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having plural diffractive elements positioned sequentially along the optical path
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G02B5/1866—Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/32—Holograms used as optical elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/34—Optical coupling means utilising prism or grating
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/017—Head mounted
    • G02B27/0172—Head mounted characterised by optical features
    • G02B2027/0174—Head mounted characterised by optical features holographic
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/017—Head mounted
    • G02B2027/0178—Eyeglass type

Definitions

  • the invention belongs to the technical field of optoelectronics, and particularly relates to an optical system and a mixed reality device.
  • Mixed reality devices include virtual reality devices and augmented reality devices.
  • Virtual reality devices only present virtual image information to users and external ambient light cannot enter the eyes of users through virtual reality devices.
  • Augmented reality devices can simultaneously display virtual image information and external ambient light. presented to the user.
  • optical waveguide technology As one of the optical systems in mixed reality devices, optical waveguide technology has gained increasing popularity due to its thinness and high penetration of external light.
  • Embodiments of the present application first provide an optical system, comprising: a projection device for projecting two beams of image light; a base layer having a base layer for respectively receiving the two beams of the image light from the projection device two side surfaces and two planes for total reflection of the two beams of the image light entering the base layer; and a diffraction grating layer disposed on at least one plane of the base layer for reflecting the The two beams of the image light propagating in the base layer are reflected and diffracted or transmitted and diffracted, wherein the energy of the target image light diffracted by the diffraction grating layer is uniformly distributed.
  • the embodiment of the present invention also discloses a mixed reality device, which includes a data processing module and the above-mentioned optical system, the data processing module transmits image information to be displayed to a projection device of the optical system to display the image.
  • FIG. 1 is a schematic structural diagram of an optical system according to an embodiment of the present invention.
  • FIG. 2 is a schematic structural diagram of an optical system according to another embodiment of the present invention.
  • Figure 3 is a view from another angle of Figure 2;
  • FIG. 4 is a schematic structural diagram of a base layer and a diffraction grating layer in an optical system according to an embodiment of the present invention
  • FIG. 5 is a diffraction efficiency diagram of image light in an optical system according to an embodiment of the present invention.
  • FIG. 6 is a diffraction absolute light intensity diagram of an image light in an optical system according to an embodiment of the present invention.
  • FIG. 7 is a schematic structural diagram of a mixed reality device according to an embodiment of the present invention.
  • an embodiment of the present application discloses an optical system 100 , which includes projection devices 101 and 102 , a base layer 400 and a diffraction grating layer.
  • Projection device for projecting two beams of image light. It may be that one projection device transmits two beams of image light, for example, the light projected by one projection device is divided into two beams of image light by means of beam splitting. In the manner shown in FIG. 1 , the two projection devices 101 and 102 respectively emit a beam of image light.
  • the two projection devices 101 and 102 may be symmetrically arranged with respect to the vertical line of the center positions of the two planes of the base layer 400 .
  • the base layer 400 has two sides for receiving the two image lights from the projection devices 101 , 102 , respectively, and two planes for total reflection of the two image lights entering the base layer 400 .
  • the cross section of the base layer 400 may be a trapezoid, and two side surfaces of the base layer 400 are respectively used to receive two beams of image light, and the two beams of image light are transmitted through total reflection in two opposite planes respectively.
  • a beam of image light enters the base layer 400 through one side surface, and the image light propagates toward the other side surface in a total reflection manner in two opposite planes of the base layer 400 .
  • the diffraction grating layers 501 and 502 which are disposed on at least one plane of the base layer 400, are used to diffract or transmit the two beams of image light propagating in the base layer 400 out.
  • the energy of the target image light 1000 diffracted by the diffraction grating layers 501 and 502 is uniformly distributed. Both the two beams of image light can be emitted through the optical system 100, and the effect of continuous pupil can be achieved.
  • the image light propagates in the base layer 400 , when it encounters a plane disposed on the base layer 400 , it emerges in the manner of reflection diffraction or transmission diffraction, and the emergent image light is called the target image light 1000 .
  • the diffraction grating layer is divided into two layers, one layer is arranged on the lower plane of the base layer 400, and the other layer is arranged on the upper plane of the base layer 400, wherein the corresponding image light of one layer is reflected and diffracted. The corresponding image light of another layer is emitted in the way of transmission diffraction.
  • the diffraction grating layers 501 and 502 are one layer, and one layer of diffraction grating layers 501 and 502 is attached to a plane of the base layer 400 , and the image light is emitted in the manner of transmission diffraction.
  • the image light encounters the diffraction grating layer It is emitted in the manner of transmission diffraction, and the energy of the emitted target image light 1000 is evenly distributed.
  • the left part of the diffraction grating layer is marked as 502
  • the right part of the diffraction grating layer is marked as 501.
  • These two parts are actually an integral diffraction grating layer.
  • the energy of the outgoing target image light 1000 is in the diffraction grating layer. In other words, the energies of the outgoing target image light 1000 corresponding to different positions of the diffraction grating layer are equal.
  • the center positions of the diffraction grating layers 501 , 502 may coincide with the center position of the base layer 400 .
  • the energy of the target image light 1000 emitted from the optical system 100 is uniformly distributed, the optical system 100 is more compact, and the target image light 1000 emitted by the optical system 100 can be respectively corresponding to the user There is no need to set two different optical systems for each eye of the user, and the mixed reality device using the optical system 100 has better immersion.
  • the projection devices 101 and 102 may specifically include a projection lens and a display screen.
  • the display screen is used to load the image information to be displayed, and then transmit the image information to be displayed to the projection lens in the form of light, and the projection lens can be used for Image information in the form of light (image light) is collimated and transmitted downstream of the optical path.
  • the projection devices 101 and 102 can be respectively attached to two side surfaces of the base layer 400 .
  • the optical system 100 may further include two coupling prisms 301 , 302 , which are respectively disposed on two sides of the base layer 400 , respectively used to pass the two beams of image light from the projection devices 101 , 102 , respectively.
  • the two sides are coupled into the base layer 400 .
  • the image light emitted by the projection device 101 may pass through the coupling prism 301 and enter the base layer 400 through one side of the base layer 400
  • the image light emitted by the projection device 102 may pass through the coupling prism 302 and enter the base layer 400 through the other side of the base layer 400 .
  • the two coupling prisms 301 and 302 can be respectively glued on two side surfaces of the base layer 400 , and the projection devices 101 and 102 can be respectively attached to the two coupling prisms 301 and 302 .
  • the two projection devices 101 , 102 may be symmetrically arranged with respect to the vertical lines of the center positions of the two planes of the base layer 400
  • the two coupling prisms 301 , 302 may also be arranged symmetrically with respect to the vertical lines of the center positions of the two planes of the base layer 400 .
  • the optical system 100 may further include two reflective elements 201, 202, which are respectively disposed on the light paths of the two beams of image light from the projection devices 101, 102 incident on the coupling prisms 301, 302, respectively, for reflecting the two beams from the projection devices 101, 102 respectively.
  • the beam of image light is reflected to the corresponding coupling prisms 301 , 302 .
  • the image light emitted by the projection devices 101 and 102 is reflected by the reflective elements 201 and 202 and then enters the coupling prisms 301 and 302 , and the coupling prisms 301 and 302 couple the image light to the base layer 400 .
  • the two coupling prisms 301 and 302 can be respectively attached to two side surfaces of the base layer 400 , and the projection devices 101 and 102 can be arranged parallel to the plane of the base layer 400 . If the projection devices 101 and 102 are located close to the edge of the base layer 400 or the outside of the base layer 400 , the ambient light will not be affected by the base layer 400 and the diffraction grating layers 501 and 502 entering the human eye, and the optical system 100 can realize both image light and external ambient light. The effect of shooting into the human eye.
  • the base layer 400 and the diffraction grating layers 501 and 502 can be made of, for example, transparent optical glass and optical plastic.
  • the high transmittance of the base layer 400 and the diffraction grating layers 501 , 502 can reduce the absorption of light by the base layer 400 and the diffraction grating layers 501 , 502 .
  • the projection devices 101 and 102 are set close to the center of the base layer 400 , it will affect the ambient light entering the human eye through the base layer 400 and the diffraction grating layers 501 and 502 , and the optical system 100 can only achieve the image light entering the human eye. Effect.
  • the two reflecting elements 201 , 202 are at a certain angle with respect to the two projection devices 101 , 102 and the two coupling prisms 301 , 302 respectively, so as to reflect the image light emitted by the projection devices 101 , 102 into the coupling prisms 301 , 302 .
  • the two projection devices 101 and 102 can be symmetrically arranged with respect to the vertical lines of the center positions of the two planes of the base layer 400
  • the two coupling prisms 301 and 302 can also be arranged symmetrically with respect to the vertical lines of the center positions of the two planes of the base layer 400 .
  • the elements 201 , 202 may also be symmetrically arranged with respect to the vertical line of the center positions of the two planes of the base layer 400 .
  • the two projection devices 101, 102, the two reflection elements 201, 202, and the two coupling prisms 301, 302 share a common base layer 400 and diffraction grating layers 501, 502, and the optical system 100 is more compact and smaller.
  • the optical system 200 may further include: a transflective element 600 disposed on the optical path from the target image light 1000 diffracted by the diffraction grating layers 501 , 502 to the human eye 700 , It is used to reflect the target image light 1000 diffracted by the diffraction grating layers 501 , 502 into the human eye and to transmit ambient light into the human eye 700 through the transflective element 600 .
  • a transflective element 600 can be added on the basis of the optical system 100 , and the target image light 1000 emitted from the optical system 100 passes through the transflective element 600
  • the image light 1001 can be obtained by the reflection of the image light 1001 , and the image light 1001 can be incident on the human eye 700 , and the ambient light transflective and transflective element 600 can be incident on the human eye 700 .
  • the optical system 200 can achieve the effect that both the image light and the external ambient light are incident on the human eye 700 .
  • the human eye 700 has a rectangular exit pupil.
  • the diffraction grating layers 501, 502 when the diffraction grating layers 501, 502 are arranged on a plane of the base layer 400, for example, on the upper surface of the base layer 400, the diffraction grating layers 501, 502 (the whole of which is a diffraction grating layer) ) is distributed axisymmetrically with respect to the grating fringes along the preset position point to the direction perpendicular to the diffraction grating layers 501, 502 (Z axis shown in FIG. 4 ), wherein the preset position point (0 point shown in FIG. 4 ) ) on the diffraction grating layers 501,502.
  • the diffraction grating layers 501 and 502 may be holographic gratings or surface relief gratings.
  • the transmission diffraction efficiency of the image light gradually increases in the direction from the edge of the diffraction grating layers 501 and 502 to the preset position point of the image light transmitted in the base layer 400 .
  • the reflection diffraction efficiency of the image light gradually decreases.
  • the diffraction efficiency is the highest at the 0 point, and the farther from the 0 point, the lower the diffraction efficiency , from the edge to the 0 point, the transmission diffraction efficiency T of the diffraction grating layer 502 part and the reflection diffraction efficiency R of the diffraction grating layer 501 part gradually increase.
  • the diffraction efficiency may also increase in steps, for example, from the edge to the 0 point, the transmission diffraction efficiency T of the diffraction grating layer 502 and the reflection diffraction efficiency R of the diffraction grating layer 501 increase in steps.
  • the incident light 2 shown in FIG. 4 propagates along the direction from the diffraction grating layer 501 to the diffraction grating layer 502 , which is similar to the incident light 1 and will not be repeated here.
  • the transmission diffraction efficiency of the image light and the reflection diffraction efficiency of the image light are axially symmetric with respect to a direction perpendicular to the diffraction grating layers 501 , 502 along a predetermined position point. It can be seen from FIG. 5 that the transmission diffraction efficiency T of the diffraction grating layer 502 and the reflection diffraction efficiency R of the diffraction grating layer 501 are symmetrically distributed with respect to the Z axis.
  • the transmission diffraction efficiency T of the diffraction grating layer 502 portion and the reflection diffraction efficiency R of the diffraction grating layer 501 portion may also be distributed asymmetrically with respect to the Z axis.
  • the transmission diffraction efficiency T of the diffraction grating layer 502 portion and the reflection diffraction efficiency R of the diffraction grating layer 501 portion may gradually increase from the edge to the 0 point, but the increasing curves may be different.
  • the transmitted diffraction light intensity value of the image light is constant; the image light transmitted in the base layer 400 In the direction from the preset position point to the other edge of the diffraction grating layers 501, 502, the reflected diffracted light intensity value of the image light is smaller than the transmitted diffracted light intensity value.
  • FIG. 6 shows the diffraction absolute light intensity distribution of the incident light 1 in the diffraction grating layer 502 and the diffraction grating layer 501, that is, the distribution of the diffraction absolute light intensity in the diffraction grating layer 502 and the diffraction grating layer 501.
  • the portion of the diffraction grating layer 502 has a nearly flat transmission energy t, that is, a constant value of the transmitted diffracted light intensity.
  • the incident light 2 propagates from the diffraction grating layer 501 part toward the diffraction grating layer 502 part, the incident light 2 also has a constant transmitted diffracted light intensity value in the diffraction grating layer 501 part.
  • the incident ray 1 When the incident ray 1 propagates from the diffraction grating layer 502 towards the diffraction grating layer 501, the incident ray 1 is extracted by the diffraction grating layer 502 for many times and transmits diffraction energy.
  • the transmission diffraction efficiency of the grating layer 501 to the incident light 1 is 1-R, and the transmission diffraction of the diffraction grating layer 501 to the incident light 1 is insignificant.
  • the transmission diffraction of the diffraction light scattering layer 502 to the incident light 2 is also insignificant.
  • the entire area of the diffraction grating layers 501, 502 has a uniform transmission diffraction energy distribution.
  • the reflected diffracted light intensity value of the image light gradually decreases.
  • the fabrication process of the diffraction grating layers 501 and 502 may be to adjust the exposure time at different positions through holographic exposure to obtain the required diffraction efficiency.
  • the present application also provides a mixed reality device, which includes a data processing module and the optical systems 100, 200 described above, the data processing module transmits image information to be displayed to the projection devices 101, 102 of the optical systems 100, 200 to display the image .
  • the data processing module in the mixed reality device is used to provide image information to be displayed, and transmit it to the projection devices 101, 102 for the optical systems 100, 200 to transmit to the human eyes.
  • the mixed reality device is used as a virtual reality device, only image information is displayed, and when the mixed reality device is used as an augmented reality device, the real image information and external environment information are displayed.
  • the mixed reality device may be, for example, a glasses-type device, which includes a glasses holder 300 and an optical system 100 connected to the glasses holder 300 , and the data processing module may be arranged in the glasses holder 300 .
  • the optical system 100 can provide an integrated all-view lens sheet, so that when the user wears it, there is no obstruction at the bridge of the nose, and can provide the augmented reality glasses with a thinner and lighter structure, a simpler structure, and a higher immersive visual experience.
  • the diffraction grating layer 501 may provide images for the left eye
  • the diffraction grating layer 502 may provide images for the right eye. Both the diffraction grating layers 501 and 502 correspond to the base layer 400 , and the base layer 400 may be a transparent waveguide.
  • the entire optical system 100 is filled with virtual images and can provide a larger eye box compared to current augmented reality glasses.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Holo Graphy (AREA)

Abstract

一种光学系统（100）及混合现实设备。光学系统（100）包括：投影装置（101,102），其用于投射两束图像光；基底层（400），其具有用于分别接收源自投影装置（101,102）的两束图像光的两个侧面以及用于将进入基底层（400）的两束图像光进行全反射的两个平面；以及衍射光栅层（501,502），其至少设置于基底层（400）的一个平面上，用于将基底层（400）中传播的两束图像光反射衍射或透射衍射出去，其中，通过衍射光栅层（501,502）衍射出去的目标图像光（1000）的能量均匀分布。光学系统（100）及混合现实设备，可以提供更紧凑的结构，提供更好的沉浸感。

Description

一种光学系统及混合现实设备 技术领域
本发明属于光电子技术领域，特别涉及一种光学系统及混合现实设备。
背景技术
混合现实设备包括虚拟现实设备和增强现实设备，虚拟现实设备是只给用户呈现虚拟图像信息而外界环境光不能通过虚拟现实设备进入用户眼中，增强现实设备是可以将虚拟图像信息和外界环境光同时呈现到用户眼中。
光波导技术作为混合现实设备中的光学系统中的一种，以其轻薄和外界光线的高穿透性的特点获得越来越高的热度。
发明内容
本申请的实施例首先提供了一种光学系统，包括：投影装置，其用于投射两束图像光；基底层，其具有用于分别接收源自所述投影装置的两束所述图像光的两个侧面以及用于将进入所述基底层的两束所述图像光进行全反射的两个平面；以及衍射光栅层，其至少设置于所述基底层的一个平面上，用于将所述基底层中传播的两束所述图像光反射衍射或透射衍射出去，其中，通过所述衍射光栅层衍射出去的目标图像光的能量均匀分布。
本发明实施例还公开了一种混合现实设备，其包括数据处理模块和上述的光学系统，所述数据处理模块将需要显示的图像信息传输至所述光学系统的投影装置中以显示图像。
本发明的目标，和特征在某种程度上将在随后的说明书中进行阐述，并且在某种程度上，基于对下文的考察研究对本领域技术人员而言将是显而易见的，或者可以从本发明的实践中得到教导。本发明的目标和其他优点可以通过下面的说明书，权利要求书，以及附图中所特别指出的结构来实现和获得。
附图说明
附图用来提供对本申请的技术方案或现有技术的进一步理解，并且构成说明书的一部分。其中，表达本申请实施例的附图与本申请的实施例一起用于解释本申请的技术方案，但并不构成对本申请技术方案的限制。
图1是根据本发明实施例的光学系统的结构示意图；
图2是根据本发明另一实施例的光学系统的结构示意图；
图3是图2的另一个角度的视图；
图4是根据本发明实施例的光学系统中的基底层和衍射光栅层的结构示意图；
图5是根据本发明实施例的光学系统中的图像光线的衍射效率图；
图6是根据本发明实施例的光学系统中的图像光线的衍射绝对光强图；
图7是根据本发明实施例的混合现实设备的结构示意图。
具体实施方式
以下将结合附图及实施例来详细说明本发明的实施方式，借此对本发明如何应用技术手段来解决技术问题，并达成相应技术效果的实现过程能充分理解并据以实施。本申请实施例以及实施例中的各个特征，在不相冲突前提下可以相互结合，所形成的技术方案均在本发明的保护范围之内。
请参考图1，本申请实施例公开了一种光学系统100，其包括投影装置101，102、基底层400和衍射光栅层。
投影装置，其用于投射两束图像光。可以是一个投影装置透射两束图像光，例如通过分光束的方式将一个投影装置投射出的光分为两束图像光。还可以是图1中示出的方式，两个投影装置101，102分别出射一束图像光。两个投影装置101,102可以相对于基底层400的两个平面中心位置的垂线对称设置。
基底层400，其具有用于分别接收源自投影装置101,102的两束图像光的两个侧面以及用于将进入基底层400的两束图像光进行全反射的两个平面。参考图1，基底层400例如其截面可以是梯形，其两个侧面分别用于接收两束图像光，两束图像光分别在相对的两个平面内进行全反射传播。具体地，一束图像光通过一个侧面入射进入基底层400，图像光会在基底层400的两个相对的平面内以全反射的方式朝向另一个侧面传播。
衍射光栅层501,502，其至少设置于基底层400的一个平面上，用于将基底层400中传播的两束图像光反射衍射或透射衍射出去。其中，通过衍射光栅层501,502衍射出去的目标图像光1000的能量均匀分布。两束图像光均可以通过光学系统100出射，可以实现光瞳连续的效果。图像光在基底层400内传播时，当遇到设置在基底层400的平面时，以反射衍射或透射衍射的方式出射，出射的图像光称之为目标图像光1000。例如，衍射光栅层分为两层，一层设置在基底层400的下面的平面上，另一层设置在基底层400的上面的平面上，其中一层对应的图像光是以反射衍射的方式出射，另一层对应的图像光是以透射衍射的方式出射。又例如，参考图1，衍射光栅层501,502为一层，一层衍射光栅层501,502贴合在基底层400的一个平面上，图像光以透射衍射的方式出射，当图像光遇到衍射光栅层时以透射衍射的方式出射，出射的目标图像光1000的能量均匀分布。图1中，衍射光栅层的左部分标记为502，衍射光栅层的右部分标记为501，这两部分实际上是一层整体的衍射光栅层，出射的目标图像光1000的能量在衍射光栅层上均匀分布，也就是说，衍射光栅层的不同位置对应的出射的目标图像光1000的能量相等。衍射光栅层501,502的中心位置可以与基底层400的中心位置重合。
通过设置投影装置101,102、基底层400和衍射光栅层501,502，光学系统100的出射的目标图像光1000的能量均匀分布，光学系统100更加紧凑，光学系统100出射的目标图像光1000可以分别对应至用户的两眼，不用分别针对用户的每只眼睛设置不同的两个光学系统，利用此光学系统100的混合现实设备的沉浸感更好。
在一些实施例中，投影装置101,102具体可以包括投影镜头和显示屏幕，显示屏幕用于加载待显示的图像信息，进而将待显示的图像信息以光的形式发射到投影镜头，投影镜头可以用于对光形式的图像信息(图像光)进行准直并传输至光路的下游。投影装置101,102可以分别贴合在基底层400的两个侧面上。
在一些实施例中，参考图1，光学系统100还可以包括两个耦合棱镜301,302，其分别设置于基底层400的两个侧面上，分别用于将源自投影装置101,102的两束图像光通过两个侧面耦合进入基底层400。投影装置101出射的图像光可以经过耦合棱镜301通过基底层400的一个侧面入射基底层400，投影装置102出射的图像光可以经过耦合棱镜302通过基底层400的另一个侧面入射基底层400。 其中，两个耦合棱镜301,302可以分别胶合在基底层400的两个侧面上，投影装置101,102分别贴合在两个耦合棱镜301,302上。两个投影装置101,102可以相对于基底层400的两个平面中心位置的垂线对称设置，两个耦合棱镜301,302也可以相对于基底层400的两个平面中心位置的垂线对称设置。
在一些实施例中，光学系统100还可以包括两个反射元件201,202，其分别设置于投影装置101,102的两束图像光对应入射至耦合棱镜301,302的光路上，用于分别将源自投影装置101,102两束图像光反射至对应的耦合棱镜301,302。投影装置101,102出射的图像光经过反射元件201,202反射后进入耦合棱镜301,302，耦合棱镜301,302再将图像光耦合入射至基底层400。其中，两个耦合棱镜301,302可以分别贴合在基底层400的两个侧面上，投影装置101,102可以与基底层400的平面平行设置。如果投影装置101,102设置的位置靠近基底层400的边缘或者基底层400的外侧，不影响环境光通过基底层400和衍射光栅层501,502射入人眼，光学系统100可以实现图像光线和外界环境光都射入人眼的效果。基底层400和衍射光栅层501,502例如可以采用透明材质的光学玻璃和光学塑料制成。高透过率的基底层400和衍射光栅层501,502可以减小光线被基底层400和衍射光栅层501,502吸收。参考图1，如果投影装置101,102设置的位置靠近基底层400的中心位置，会影响环境光通过基底层400和衍射光栅层501,502射入人眼，光学系统100只能实现图像光线射入人眼的效果。两个反射元件201，202分别相对于两个投影装置101,102和两个耦合棱镜301,302呈一定角度，以将投影装置101,102出射的图像光线反射到耦合棱镜301,302中。两个投影装置101,102可以相对于基底层400的两个平面中心位置的垂线对称设置，两个耦合棱镜301,302也可以相对于基底层400的两个平面中心位置的垂线对称设置，两个反射元件201,202也可以相对于基底层400的两个平面中心位置的垂线对称设置。两个投影装置101,102、两个反射元件201,202、两个耦合棱镜301,302共用共同的基底层400和衍射光栅层501,502，光学系统100更紧凑，体积更小。
在一些实施例中，参考图2和图3，光学系统200还可以包括：半反半透元件600，其设置于通过衍射光栅层501,502衍射出去的目标图像光1000至人眼700的光路上，用于将衍射光栅层501,502衍射出的目标图像光1000反射入人眼中，并且用于供环境光通过半反半透元件600透射入人眼700中。当光学系统100只能实现图像光线射入人眼的效果时，可以通过在光学系统100的基础上增加半反 半透元件600，光学系统100出射的目标图像光1000经过半反半透元件600的反射得到图像光1001，图像光1001可以射入人眼700，环境光透射半反半透元件600可以射入人眼700。光学系统200可以实现图像光线和外界环境光都入射到人眼700的效果。人眼700处具有矩形的出瞳。
在上面的光学系统中，参考图4，当衍射光栅层501,502设置在基底层400的一个平面上时，例如设置在基底层400的上表面，衍射光栅层501,502(其整体是一层衍射光栅层)相对于沿预设位置点到垂直于衍射光栅层501,502的方向(图4中示出的Z轴)的光栅条纹呈轴对称分布，其中，预设位置点(图4中示出的0点)位于衍射光栅层501,502上。图4中的X轴位于基底层400和衍射光栅层501,502之间，0点位于衍射光栅层501,502的中心位置(0点位于衍射光栅层501部分和衍射光栅层502部分的分界处)，Z轴为0点沿垂直于衍射光栅层501,502的方向。其中，衍射光栅层501,502可以是全息光栅，可以是表面浮雕光栅。
参考图5，在通过衍射光栅层501,502透射衍射出去的情况下，在基底层400中传输的图像光从衍射光栅层501,502的边缘到预设位置点的方向上，图像光的透射衍射效率逐渐增加；在基底层400中传输的图像光从预设位置点到衍射光栅层501,502的另一边缘的方向上，图像光的反射衍射效率逐渐减少。图4中示出的入射光线1(其-1级次的透射衍射和反射衍射的光线均垂直于基底层400平面面)沿着衍射光栅层502部分到衍射光栅层501部分的方向传播，其在图5中的衍射光栅层502部分的透射衍射效率T和衍射光栅层501部分的反射衍射效率R的分布可以看出，衍射效率在0点处最高，越离0点远，衍射效率越低，从边缘到0点，衍射光栅层502部分的透射衍射效率T和衍射光栅层501部分的反射衍射效率R逐渐增加。衍射效率也可以是梯级增加，例如，从边缘到0点，衍射光栅层502部分的透射衍射效率T和衍射光栅层501部分的反射衍射效率R呈梯级增加。图4中示出的入射光线2沿着衍射光栅层501部分到衍射光栅层502部分的方向传播，其与入射光线1是类似的，在此不再赘述。
在一些实施例中，图像光的透射衍射效率和图像光的反射衍射效率相对于沿预设位置点到垂直于衍射光栅层501,502的方向呈轴对称。从图5可以看出，衍射光栅层502部分的透射衍射效率T和衍射光栅层501部分的反射衍射效率R是相对于Z轴对称分布的。当然，在一些情况下，衍射光栅层502部分的透射衍射 效率T和衍射光栅层501部分的反射衍射效率R也可以相对于Z轴不对称分布。衍射光栅层502部分的透射衍射效率T和衍射光栅层501部分的反射衍射效率R从边缘到0点可以逐渐增加，但是增加的曲线可以是不同的。
参考图6，在基底层400中传输的图像光从衍射光栅层501,502的边缘到预设位置点的方向上，图像光的透射衍射光强值为恒值；在基底层400中传输的图像光从预设位置点到衍射光栅层501,502的另一边缘的方向上，图像光的反射衍射光强值小于透射衍射光强值。图6中示出了入射光线1在衍射光栅层502部分和衍射光栅层501部分的的衍射绝对光强分布，即衍射绝对光强值在衍射光栅层502部分和衍射光栅层501部分的分布。衍射光栅层502部分具有近乎平坦的透射能量t，即恒值的透射衍射光强值。类似地，入射光线2从衍射光栅层501部分朝向衍射光栅层502部分传播时，入射光线2在衍射光栅层501部分同样具有恒值的透射衍射光强值。入射光线1从衍射光栅层502部分朝向衍射光栅层501传播时，入射光线1被衍射光栅层502多次提取透射衍射能量，当传播到衍射光栅层501部分时剩余的光线能量非常弱，并且衍射光栅层501部分对入射光线1的透射衍射效率为1-R，衍射光栅层501部分对入射光线1的透射衍射微不足道，同理，衍射光散层502部分对入射光线2的透射衍射也微不足道，衍射光栅层501,502的整个区域具有均匀的透射衍射能量分布。
在一些实施例中，在基底层400中传输的图像光从预设位置点到衍射光栅层501,502的另一边缘的方向上，图像光的反射衍射光强值逐渐减少。图像光的反射衍射光强值越小，对衍射光栅层501,502的透射衍射效果越好。
衍射光栅层501,502的制作工艺可以是通过全息曝光调整不同位置处的曝光时间获得需要的衍射效率。
参考图7，本申请还提供了一种混合现实设备，其包括数据处理模块和上面描述的光学系统100,200，数据处理模块将需要显示的图像信息传输至光学系统100,200的投影装置101,102中以显示图像。混合现实设备中的数据处理模块用于提供需要显示的图像信息，并将其传输至投影装置101,102以供光学系统100,200传导至人眼中。混合现实设备作为虚拟现实设备时，只显示图像信息，混合现实设备作为增强现实设备时，现实图像信息和外界环境信息。混合现实设备例如可以是眼镜式设备，其包括眼镜支架300和连接在眼镜支架300上的光学系统100，数据处理模块可以设置在眼镜支架300内。光学系统100可以提供具有一体的全 视透镜片，使得用户在佩戴时，鼻梁处无任何遮挡，可以提供增强现实眼镜更轻薄的结构，更简单的结构以及更高的沉浸视觉体验。其中，衍射光栅层501部分可以为左眼提供图像，衍射光栅层502部分为右眼提供图像，衍射光栅层501部分和502部分均对应有基底层400，基底层400可以为透明波导。整个光学系统100充满虚拟图像，相比较目前的增强现实眼镜，可以提供更大的眼盒。
以上所述，仅为本发明较佳的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉该技术的人员在本发明所揭露的技术范围内，可轻易想到的变化或替换，都应涵盖在本发明的保护范围之内。因此，本发明的保护范围应该以权利要求的保护范围为准。

Claims (10)

  1. 一种光学系统，其特征在于，包括：
    投影装置，其用于投射两束图像光；
    基底层，其具有用于分别接收源自所述投影装置的两束所述图像光的两个侧面以及用于将进入所述基底层的两束所述图像光进行全反射的两个平面；以及
    衍射光栅层，其至少设置于所述基底层的一个平面上，用于将所述基底层中传播的两束所述图像光反射衍射或透射衍射出去，其中，通过所述衍射光栅层衍射出去的目标图像光的能量均匀分布。
  2. 根据权利要求1所述的光学系统，其特征在于，当所述衍射光栅层设置在所述基底层的一个平面上时，所述衍射光栅层相对于沿预设位置点到垂直于所述衍射光栅层的方向的光栅条纹呈轴对称分布，其中，所述预设位置点位于所述衍射光栅层上。
  3. 根据权利要求2所述的光学系统，其特征在于，在通过所述衍射光栅层透射衍射出去的情况下，在所述基底层中传输的所述图像光从所述衍射光栅层的边缘到所述预设位置点的方向上，所述图像光的透射衍射效率逐渐增加；在所述基底层中传输的所述图像光从所述预设位置点到所述衍射光栅层的另一边缘的方向上，所述图像光的反射衍射效率逐渐减少。
  4. 根据权利要求3所述的光学系统，其特征在于，所述图像光的透射衍射效率和所述图像光的反射衍射效率相对于沿所述预设位置点到垂直于所述衍射光栅层的方向呈轴对称。
  5. 根据权利要求3所述的光学系统，其特征在于，在所述基底层中传输的所述图像光从所述衍射光栅层的边缘到所述预设位置点的方向上，所述图像光的透射衍射光强值为恒值；在所述基底层中传输的所述图像光从所述预设位置点到所述衍射光栅层的另一边缘的方向上，所述图像光的反射衍射光强值小于所述透射衍射光强值。
  6. 根据权利要求5所述的光学系统，其特征在于，在所述基底层中传输的所述图像光从所述预设位置点到所述衍射光栅层的另一边缘的方向上，所述图像光的反射衍射光强值逐渐减少。
  7. 根据权利要求1所述的光学系统，其特征在于，所述光学系统还包括：
    两个耦合棱镜，其分别设置于所述基底层的两个侧面上，分别用于将源自所 述投影装置的两束所述图像光通过两个所述侧面耦合进入所述基底层。
  8. 根据权利要求7所述的光学系统，其特征在于，所述光学系统还包括：
    两个反射元件，其分别设置于所述投影装置的两束所述图像光对应入射至所述耦合棱镜的光路上，用于分别将源自所述投影装置两束所述图像光反射至对应的所述耦合棱镜。
  9. 根据权利要求8所述的光学系统，其特征在于，所述光学系统还包括：
    半反半透元件，其设置于通过所述衍射光栅层衍射出去的目标图像光至人眼的光路上，用于将所述衍射光栅层衍射出的所述目标图像光反射入人眼中，并且用于供环境光通过所述半反半透元件透射入人眼中。
  10. 一种混合现实设备，其特征在于，包括数据处理模块和权利要求1-9中任一项所述的光学系统，所述数据处理模块将需要显示的图像信息传输至所述光学系统的投影装置中以显示图像。
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