WO2022161056A1 - 波导模组和显示*** - Google Patents

波导模组和显示*** Download PDF

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Publication number
WO2022161056A1
WO2022161056A1 PCT/CN2021/140976 CN2021140976W WO2022161056A1 WO 2022161056 A1 WO2022161056 A1 WO 2022161056A1 CN 2021140976 W CN2021140976 W CN 2021140976W WO 2022161056 A1 WO2022161056 A1 WO 2022161056A1
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Prior art keywords
layer
waveguide
light
grating
coupling
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PCT/CN2021/140976
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English (en)
French (fr)
Inventor
李民康
周海峰
刘力铭
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华为技术有限公司
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Publication of WO2022161056A1 publication Critical patent/WO2022161056A1/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
    • G02B27/017—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
    • G02B27/01—Head-up displays
    • 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

Definitions

  • the invention relates to the technical field of augmented reality display, in particular to a waveguide module and a display system using the waveguide module.
  • AR Augmented Reality
  • the AR glasses include a diffractive optical waveguide module, and the diffractive optical waveguide module includes a waveguide and an exit pupil grating (or outcoupling grating).
  • the exit pupil grating is used to couple the received light out of the waveguide into the human eye based on the diffraction effect of the grating. Due to the symmetry of the diffraction of light by the grating, part of the light at the exit pupil grating is coupled out into the human eye, and the other part enters the external environment, thereby causing the problem of light leakage.
  • light leakage exposes the information displayed by the light to the external environment, and user privacy is leaked; on the other hand, light leakage makes the AR glasses appear bright in a large area when viewed from the outside, which affects the appearance; The amount of light is in the same order of magnitude, resulting in low waveguide efficiency and increased power consumption.
  • One way to solve the problem of light leakage in the prior art is to provide an absorbing element on the side of the exit pupil grating away from the waveguide to absorb the leaked light and prevent it from being incident to the external environment.
  • the amount of light absorbed by the absorbing element is in the same order of magnitude as the amount of light incident to the human eye, and the light utilization efficiency of the absorbing element is low.
  • the absorption element is a separate component from the waveguide, and the addition of the absorption element will increase the overall thickness of the device.
  • Another way to solve the above problem in the prior art is to provide a protective glass coated with a reflective filter film on the side of the exit pupil grating away from the waveguide to prevent the missed light from entering the external environment.
  • the protective glass coated with the reflective filter film is a separate component from the waveguide, and the addition of protective glass will also increase the overall thickness of the device.
  • a waveguide module comprising: a waveguide, an in-coupling grating and an out-coupling grating; the waveguide is used to receive and guide a first image light to the in-coupling grating; the in-coupling grating is disposed on the incoupling grating.
  • the waveguide is used for diffracting the first image light and guiding the diffracted first image light to the waveguide; the waveguide is also used for guiding the diffracted first image light coupled into the grating to the waveguide.
  • the coupling-out grating is arranged on the waveguide and is located on the same side of the waveguide as the coupling-in grating, the coupling-out grating includes a diffraction layer, a connecting layer and an anti-leakage layer;
  • the diffraction grating A layer is fixedly arranged on the surface of the waveguide for diffracting part of the first image light and guiding the diffracted part of the first image light to the waveguide;
  • the connecting layer is located on the diffractive layer and the anti-leakage light between the layers, for fixedly connecting the diffractive layer and the anti-leakage layer;
  • the anti-leakage layer is located on the side of the connecting layer away from the waveguide, and is used for reflecting from the Another part of the first image light emitted from the diffractive layer, so that the reflected another part of the first image light is diffracted by the diffractive layer and then emitted to the waveguide;
  • the waveguide is also used to pass the coupling
  • the light leakage prevention layer reflects the first image light to the diffractive layer, so that the first image light emitted from the diffractive layer away from the waveguide can be recycled, which can effectively improve the light leakage problem of the waveguide module. It is beneficial to improve the aesthetics of the display system and also to improve the utilization rate of light energy.
  • the connecting layer is located between the diffractive layer and the anti-leakage layer, so that the connecting layer and the diffractive layer can be used to jointly carry the anti-leakage layer, avoiding additionally providing a substrate for carrying the anti-leakage layer (for example, a glass substrate, a glass substrate).
  • a substrate for carrying the anti-leakage layer for example, a glass substrate, a glass substrate
  • the thickness of the coupling layer is in the order of millimeters)
  • the thickness of the connecting layer is in the order of micrometers (for example, about ten micrometers), so it is beneficial to reduce the overall thickness and weight of the coupling-out grating, thereby reducing the overall thickness and weight of the display system.
  • connection layer plays the role of fixed connection, which is used to fix the diffractive layer and the anti-light leakage layer on both sides of it as a whole, so that each layer structure (mainly refers to the diffractive layer, the connecting layer and the anti-light leakage layer) ) is more compact.
  • each layer structure mainly refers to the diffractive layer, the connecting layer and the anti-light leakage layer
  • it is beneficial to reduce the overall thickness and weight of the coupling-out grating, thereby reducing the overall thickness and weight of the display system, and also helping to improve the overall reliability of the display system. .
  • the light leakage prevention layer is a reflective filter film.
  • the anti-leakage layer is a reflective volume grating.
  • the reflector grating is a photosensitive material doped with a liquid crystal material.
  • the liquid crystal material By doping the liquid crystal material, it is beneficial to improve the refractive index modulation of the anti-leakage layer.
  • the refractive index modulation When the refractive index modulation is increased, the thickness of the anti-leakage layer required to achieve the same refraction effect is lower. Therefore, by doping the liquid crystal material, the It is beneficial to reduce the thickness of the light leakage prevention layer.
  • the index of refraction of the tie layer is different from the index of refraction of the diffractive layer.
  • the first image light can be transmitted from the diffractive layer to the connection layer and out from the connection layer.
  • connection layer is formed by plating.
  • connection layer fixedly connecting the light leakage prevention layer and the surface of the diffractive layer fixedly connected to the connection layer there is a minimum vertical distance d between the surface of the connection layer fixedly connecting the light leakage prevention layer and the surface of the diffractive layer fixedly connected to the connection layer, 0 nm ⁇ d ⁇ 10 ⁇ m.
  • connection layer is in the order of micrometers, which is beneficial to reduce the thickness and weight of the diffraction module.
  • the surface on which the connecting layer is fixedly connected to the anti-light leakage layer is a continuous and flat surface, and the surface on which the connecting layer is fixedly connected to the anti-light leakage layer and the diffractive layer is fixedly connected to the connecting layer There is a minimum vertical distance d between the surfaces of 0nm ⁇ d ⁇ 10 ⁇ m.
  • the connecting layer is located between the diffractive layer and the anti-leakage layer, and plays the role of a flat diffractive layer, so that the connecting layer can be used to carry the anti-leakage layer, avoiding additionally providing a substrate for carrying the anti-leakage layer (for example, a glass substrate,
  • a substrate for carrying the anti-leakage layer for example, a glass substrate
  • the thickness of the glass substrate is in the order of millimeters)
  • the thickness of the connecting layer is in the order of micrometers (for example, about ten micrometers), so it is beneficial to reduce the overall thickness and weight of the outcoupling grating, thereby reducing the overall thickness and weight of the display system.
  • the first image light includes multiple primary color lights with different wavelengths
  • the coupling-in grating and the diffractive layer are used to diffract at least one primary color light in the first image light.
  • the coupling grating and the diffractive layer diffract all the primary color light, it is beneficial to reduce the thickness of the coupling grating and the diffractive layer;
  • the multi-layered waveguide modules respectively diffract each primary color light in the first image light, which is beneficial to improve the color of the second image light. uniformity and increase the field of view of the second image light.
  • the primary color light diffracted by the coupling-in grating is the same primary color light diffracted by the diffractive layer.
  • a waveguide module including a first waveguide, a first coupling-in grating, a first coupling-out grating, a second waveguide, a second coupling-in grating, and a second coupling-out grating; the first coupling grating
  • the input grating and the first coupling-out grating are arranged on the same side of the first waveguide, the first waveguide is used to receive the first image light including three primary color lights, and the first waveguide is used to guide at least one The primary color light is coupled to the first in-coupling grating, and the remaining primary color light is guided to the second waveguide;
  • the first coupled-in grating is used for diffracting the at least one primary color light, and is used for guiding the diffracted at least one primary color light to the first waveguide;
  • the first waveguide is also used to guide the at least one primary color light diffracted by the first coupling grating to the first coupling grating; the first coupling grating
  • the part of at least one primary color light is guided to the first waveguide;
  • the first connecting layer is located between the first diffractive layer and the first anti-leakage layer, and is used for fixedly connecting the first diffractive layer and the the first anti-leakage layer;
  • the first anti-leakage layer is located on the side of the first connection layer away from the first waveguide, and is used for reflection and diffraction from the first in a direction away from the first waveguide
  • the second coupling grating and the The second out-coupling grating is disposed on the same side of the second waveguide, and the second waveguide is used to receive and guide the remaining primary color light to the second in-coupling grating; the second in-coupling grating is used for pairing The remaining primary color light is diffracted
  • the above-mentioned waveguide module by increasing the number of waveguides, coupled-in gratings and coupled-out gratings, reduces the number of primary color lights that need to be guided by each waveguide, so that each waveguide has a better reflection effect on the primary color light guided by the waveguides. It is beneficial to improve the color uniformity of the second image light and also to increase the field of view of the second image light.
  • the waveguide module further includes a third waveguide, a third coupling-in grating, and a third coupling-out grating
  • the first image light includes a first primary color light, a second primary color light, and a third primary color light
  • the first waveguide is used for guiding the first primary color light to the first coupling grating, and guiding the second primary color light and the third primary color light to the second waveguide
  • the first coupling in The grating and the first diffraction layer are used for diffracting the first primary color light
  • the second waveguide is used for guiding the second primary color light to the second coupling-in grating, and guiding the third primary color light to the the third waveguide
  • the second coupling grating and the second diffractive layer are used for diffracting the second primary color light
  • the third coupling grating and the third coupling out grating are arranged on the first On the same side of the three waveguides, the third waveguide is used for guiding the third primary color light to
  • the above-mentioned waveguide module by increasing the number of waveguides, coupled-in gratings and coupled-out gratings, reduces the number of primary color lights that need to be guided by each waveguide, so that each waveguide has a better reflection effect on the primary color light guided by the waveguides. It is beneficial to improve the color uniformity of the second image light and also to increase the field of view of the second image light.
  • a display system comprising: a microdisplay for emitting a first image light; and at least one waveguide module located on an optical path of the first image light, each waveguide module as described above any one of the waveguide modules.
  • the light leakage prevention layer reflects the first image light to the diffractive layer, so that the first image light emitted from the diffractive layer away from the waveguide can be recycled, which can effectively improve the light leakage problem of the waveguide module. It is beneficial to improve the aesthetics of the display system and also to improve the utilization rate of light energy.
  • the connecting layer is located between the diffractive layer and the anti-leakage layer, so that the connecting layer and the diffractive layer can be used to jointly carry the anti-leakage layer, avoiding additionally providing a substrate for carrying the anti-leakage layer (for example, a glass substrate, a glass substrate).
  • a substrate for carrying the anti-leakage layer for example, a glass substrate, a glass substrate
  • the thickness of the coupling layer is in the order of millimeters)
  • the thickness of the connecting layer is in the order of micrometers (for example, about ten micrometers), so it is beneficial to reduce the overall thickness and weight of the coupling-out grating, thereby reducing the overall thickness and weight of the display system.
  • connection layer plays the role of fixed connection, which is used to fix the diffractive layer and the anti-light leakage layer on both sides of it as a whole, so that each layer structure (mainly refers to the diffractive layer, the connecting layer and the anti-light leakage layer) ) is more compact.
  • each layer structure mainly refers to the diffractive layer, the connecting layer and the anti-light leakage layer
  • it is beneficial to reduce the overall thickness and weight of the coupling-out grating, thereby reducing the overall thickness and weight of the display system, and also helping to improve the overall reliability of the display system. .
  • FIG. 1A is a schematic structural diagram of a display system in Embodiment 1 of the present application.
  • FIG. 1B is another schematic structural diagram of the display system in the first embodiment of the present application.
  • FIG. 2 is a schematic diagram of an optical path structure in the display system shown in FIG. 1A .
  • FIG. 3 is a schematic diagram of the spectral distribution of the first image light.
  • FIG. 4 is a schematic diagram showing the reflectance of the light leakage preventing layer in FIG. 2 to each primary color light in the first image light.
  • FIG. 5 is a schematic structural diagram of a display system in Embodiment 2 of the present application.
  • FIG. 6 is a schematic diagram of an optical path structure in the display system according to the second embodiment of the present application.
  • FIG. 7 is a schematic diagram of the reflectivity of each primary color light in the first image light by the first waveguide module in FIG. 6 .
  • FIG. 8 is a schematic diagram showing the reflectivity of each primary color light in the first image light by the second waveguide module in FIG. 7 .
  • FIG. 9 is a schematic structural diagram of a display system in Embodiment 3 of the present application.
  • FIG. 10 is a schematic structural diagram of a display system in Embodiment 3 of the present application.
  • the outcoupling grating area of the present application can be flattened and an anti-leakage layer is provided, so as to reduce the diffractive optical waveguide on the basis of preventing light leakage from the diffractive optical waveguide thickness and weight.
  • This embodiment provides a display system 10 based on Augmented Reality (AR).
  • Display system 10 may combine real and virtual images to generate AR images.
  • the user wears the display system 10 , and the AR image generated by the display system 10 enters the human eye 40 , and the user can observe the AR image generated by the display system 10 .
  • the display system 10 is AR glasses, and the user can wear the AR glasses on the eyes to observe images.
  • the display system 10 may also be an AR helmet or the like.
  • the display system 10 includes a microdisplay 11 and a waveguide module 12 .
  • the microdisplay 11 is used for emitting the first image light L1.
  • the waveguide module 12 is used for receiving and modulating the first image light L1 to generate the second image light L2 and output.
  • the second image light L2 may be directed into the human eye 40 to show the AR image to the user.
  • the first image light L1 includes multiple primary color lights, and the multiple primary color lights can cooperate with each other to modulate a color image.
  • the first image light L1 includes three primary color lights with different wavelengths.
  • the three primary color lights are: primary color light R (red light), primary color light G (green light), and primary color light B (blue light).
  • the waveguide module 12 is used to modulate the primary color light R, the primary color light G, and the primary color light B, respectively.
  • the waveguide module 12 includes a waveguide 121 , an in-coupling grating 122 and an out-coupling grating 123 disposed on the same side of the waveguide 121 .
  • the microdisplay 11 is located on the side of the waveguide 121 away from the coupling-in grating 122 and the coupling-out grating 123 .
  • the waveguide module 12 is located on the optical path of the first image light L1.
  • the waveguide 121 is used for receiving the first image light L1 and for guiding the first image light L1 to the coupling-in grating 122 and the coupling-out grating 123 successively. After the first image light L1 is incident on the waveguide 121 , it can be guided to the coupling-in grating 122 by the waveguide 121 .
  • the coupling-in grating 122 is used to first diffract the first image light L1 and guide the diffracted first image light L1 to the waveguide 121 .
  • the outcoupling grating 123 is used to second diffract the received first image light L1 and guide it to the waveguide 121 .
  • the waveguide 121 is used to guide the light guided by the outcoupling grating 123 to the human eye 40 .
  • the light diffracted twice, which is emitted from the waveguide 121 and guided to the human eye 40, is defined as the above-described second image light L2.
  • the outcoupling grating 123 includes a diffractive layer 1231 , a connection layer 1232 and an anti-leakage layer 1233 .
  • the diffractive layer 1231 is fixed on the surface of the waveguide 121 .
  • the connection layer 1232 is fixedly disposed on the surface of the waveguide 121 on which the diffractive layer 1231 is disposed and covers the diffractive layer 1231 .
  • the diffractive layer 1231 is a one-dimensional or two-dimensional diffraction grating, and is used for diffracting each primary color light in the received first image light L1 respectively.
  • the grating period of the diffraction layer 1231 is 100 nanometers to 1000 nanometers, the grating height is 20 nanometers to 1000 nanometers, and the shape of the grating can be rectangular, inclined, blazed grating, or the like.
  • the diffractive layer 1231 may have a single-layer structure or a multi-layer structure. When the diffractive layer 1231 has a single-layer structure, the single layer is used to diffract all the primary color light in the first image light L1.
  • each of the layers is used to diffract at least one primary color light in the first image light L1.
  • each layer is used to diffract one of the primary color light R, the primary color light G, and the primary color light B in the first image light L1.
  • the diffractive layer 1231 adopts a single-layer structure, it is beneficial to reduce the overall thickness.
  • the diffraction layer 1231 adopts a multi-layer structure since each layer is used to diffract one of the primary colors of light, it is beneficial to reduce the complexity of the grating structure.
  • the diffractive layer 1231 After diffracting the first image light L1 , the diffractive layer 1231 guides the diffracted first image light L1 to the waveguide 121 . However, due to the manufacturing process and other reasons, a part of the first image light L1 incident on the diffractive layer 1231 may exit toward the diffractive layer 1231 away from the waveguide 121, so that the first image light L1 incident on the diffractive layer 1231 cannot be completely diffracted. It is then directed back to the waveguide 121 .
  • the connection layer 1232 is a light-transmitting material, such as silicon dioxide, titanium dioxide, zirconium dioxide, polymethyl methacrylate (PMMA), and the like.
  • the first image light L1 emitted toward the side of the diffractive layer 1231 away from the waveguide 121 may be transmitted through the connection layer 1232 .
  • the connection layer 1232 is made of a material with a smaller haze. In this embodiment, the connection layer 1232 is made of a material with a haze of less than 0.1, which is beneficial to reduce the light loss when the first image light L1 passes through the connection layer 1232 .
  • the diffractive layer 1231 has a first refractive index with respect to the first image light L1
  • the connection layer 1232 has a second refractive index with respect to the first image light L1.
  • the first refractive index is different from the second refractive index so that a refractive index difference is generated between the diffractive layer 1231 and the connection layer 1232 , so that the first image light L1 can be transmitted from the diffractive layer 1231 to the connection layer 1232 and from the connection layer 1232 go out.
  • the refractive index (ie, the first refractive index) of the diffractive layer 1231 is 1.4 to 2.6
  • the refractive index (ie, the second refractive index) of the connecting layer 1232 is also 1.4 to 2.6.
  • the diffractive layer 1231 can be a rectangular grating, a slant grating, a blazed grating, etc., which may have grooves, slits, etc., that is, the surface of the diffractive layer 1231 away from the waveguide 121 (defined as the contact surface S1 ) is not a continuous, flat surface.
  • the connection layer 1232 covers the diffractive layer 1231 and is used to fill the discontinuous and uneven areas on the contact surface S1, and the surface of the connection layer 1232 away from the contact surface S1 is formed as a continuous and flat surface, so as to carry and fix the connection of the anti-leakage layer 1233 .
  • the connection layer 1232 may be a thin film covering the diffractive layer 1231 formed by processes such as coating, spin coating and drying. There is a minimum vertical distance d between the surface of the connection layer 1232 away from the diffractive layer 1231 and the contact surface S1 of the diffractive layer 1231 , 0 nm ⁇ d ⁇ 10 ⁇ m (including the endpoint). Since the contact surface S1 may be uneven, the above-mentioned minimum vertical distance refers to the vertical distance between the point on the contact surface S1 closest to the surface of the connection layer 1232 away from the diffraction layer 1231 and the surface of the connection layer 1232 away from the diffraction layer 1231 .
  • the minimum distance d can be equal to 0 nm
  • the connection layer 1232 does not cover the contact surface S1, that is, the contact surface S1 is exposed relative to the connection layer 1232, and the connection layer is fixedly connected to the light leakage prevention layer 1233. It is in direct contact with the anti-leakage layer 1233, and is used to jointly carry the anti-leakage layer 1233. At this time, the overall thickness of the coupling-out grating 123 is relatively small.
  • the connecting layer 1232 covers the contact surface S1
  • the side of the connecting layer that is fixedly connected to the anti-leakage layer 1233 is directly in contact with the anti-light leakage layer 1233
  • the connecting layer 1232 is fixedly connected to the anti-leakage layer.
  • One side of 1233 plays a flat role on the diffractive layer 1231 and is used to carry the anti-leakage layer 1233.
  • the surface contact area between the connection layer 1232 and the anti-light-leakage layer 1233 is larger, which is beneficial to improve the fixing effect.
  • the light leakage preventing layer 1233 serves to receive and reflect the first image light L1 incident from the connection layer 1232 .
  • the first image light L1 reflected by the light leakage prevention layer 1233 can be re-incident to the diffractive layer 1231 to be diffracted by the diffractive layer 1231 and then output to the waveguide 121 .
  • the light leakage prevention layer 1233 is a thin film layer with a very small thickness (the thickness is in the order of microns), which can be directly formed on the surface of the connection layer 1232 away from the diffractive layer 1231 by means of coating. Since both the connection layer 1232 and the anti-light leakage layer 1233 are thin film layers with a thickness of micrometers, the two can be fixedly connected by natural adhesion between the thin film layers.
  • the anti-leakage layer 1233 is a reflective filter film, and its manufacturing process is relatively mature, and it is easy to realize mass production.
  • the light-leakage prevention layer 1233 includes multiple layers of thin films having different refractive indices and a metal layer stacked in sequence, and the multilayer thin films and the metal layer are used to ensure high reflectivity for a specific wavelength and spectral range.
  • the light leakage prevention layer 1233 can also be a reflective volume grating.
  • the reflector grating is a photosensitive material, such as a photosensitive resin.
  • the reflector grating can be formed by exposure and development. Since the exposure device is simple, when the light leakage prevention layer 1233 is the reflector grating, the cost is low.
  • the thickness of the reflector grating is 5 microns to 1000 microns.
  • liquid crystal material can be doped therein. Doping the liquid crystal material is beneficial to improve the degree of refractive index modulation of the light leakage prevention layer 1233 .
  • the thickness of the light leakage prevention layer 1233 required to achieve the same refraction effect is lower. Therefore, when the light leakage prevention layer 1233 is a reflector grating, it is beneficial to reduce the thickness of the light leakage prevention layer 1233 by doping the liquid crystal material.
  • the light leakage prevention layer 1233 When the light leakage prevention layer 1233 is a reflective volume grating, it can be a single-layer structure or a multi-layer structure stacked in sequence. When the light-leakage prevention layer 1233 is a single-layer structure, the single-layer structure has high reflectivity for all primary color lights at the same time, which is beneficial to reduce the overall thickness of the light-leakage prevention layer 1233 . When the light leakage prevention layer 1233 is a multi-layer structure stacked in sequence, for example, a three-layer structure, each layer structure has a high reflectivity for a certain primary color light in the first image light L1, which is beneficial to reduce the complexity of the grating structure.
  • the primary color light R has a center wavelength ⁇ R , a spectral width of ⁇ R , and a spectral range of 633 ⁇ 2 nm.
  • the primary color light G has a center wavelength ⁇ G , a spectral width of ⁇ G , and a spectral range of 532 ⁇ 2 nm.
  • the primary color light B has a central wavelength ⁇ B , a spectral width of ⁇ B , and a spectral range of 450 ⁇ 2 nm.
  • the anti-leakage layer 1233 has the same reflectance to each primary color light, and has a reflectance of 100% to light with wavelengths ⁇ R , ⁇ G , and ⁇ B .
  • the field of view of the first image light L1 is enlarged, so the field of view of the second image light L2 is larger than that of the first image light L1.
  • the first image light L1 emitted from the side of the diffractive layer 1231 away from the waveguide 121 can be recycled, which can effectively improve the
  • the problem of light leakage of the waveguide module 12 is beneficial to improve the aesthetics of the display system 10 and also to improve the utilization rate of light energy.
  • the connecting layer 1232 is located between the diffractive layer 1231 and the anti-light leakage layer 1233, and the connecting layer 1232 functions as a contact surface S1 of the flat diffractive layer 1231, so that the connecting layer 1232 can be used to carry the anti-leakage layer 1233, avoiding the need for additional
  • a substrate for carrying the anti-leakage layer 1233 is provided (for example, a glass substrate is selected, and the thickness of the glass substrate is in the order of millimeters), and the thickness of the connecting layer 1232 is in the order of micrometers (for example, about ten micrometers), so it is beneficial to reduce the outcoupling grating 123 to reduce the overall thickness and weight of the display system 10, thereby reducing the overall thickness and weight of the display system 10.
  • connection layer 1232 plays the role of fixed connection, and is used to fixedly connect the diffractive layer 1231 and the anti-light leakage layer 1233 located on both sides of the diffractive layer 1231 as a whole, so that each layer structure (mainly refers to the diffractive layer 1231, the connection layer
  • the space between 1232 and the anti-light leakage layer 1233) is more compact, which is beneficial to reduce the overall thickness and weight of the coupling-out grating 123, thereby reducing the overall thickness and weight of the display system 10. It is beneficial to improve the overall reliability of the display system 10 .
  • FIG. 5 is mainly used to illustrate the overall structure of the display system 20, and the specific structure of the waveguide module is not shown
  • the display system 20 provided in this embodiment is basically the same as the display system 10 in the first embodiment.
  • the main difference between the two is that the display system 20 includes two waveguide modules.
  • the following mainly describes the differences between the second embodiment and the first embodiment.
  • the display system 20 includes a microdisplay 21 , a first waveguide module 22 and a second waveguide module 23 .
  • the first waveguide module 22 and the second waveguide module 23 are stacked on each other, and the first waveguide module 22 is located between the microdisplay 21 and the second waveguide module 23 .
  • the display system 20 further includes a glass frame 24 .
  • the glass frame 24 is located on the periphery of the first waveguide module 22 and the second waveguide module 23, and is used for fixing the first waveguide module 22 and the second waveguide module 23 to keep the first waveguide module 22 and the second waveguide module 23.
  • the positions of the groups 23 are not shifted from each other.
  • the glass frame 24 has a bearing portion 241 , and the bearing portion 241 protrudes between the first waveguide module 22 and the second waveguide module 23 .
  • the thickness of the bearing portion 241 itself creates an air gap 25 between the first waveguide module 22 and the second waveguide module 23 .
  • the width of the air gap 25 is less than 0.1 mm.
  • the microdisplay 21 is used for emitting the first image light L1.
  • the first waveguide module 22 and the second waveguide module 23 are located on the optical path of the first image light L1 , and are used for receiving and modulating the first image light L1 to generate the second image light L2 and exit.
  • the second image light L2 may be directed into the human eye 40 to show the AR image to the user.
  • the first image light L1 includes three primary color lights with different wavelengths.
  • the three primary color lights include: primary color light R (red light), primary color light G (green light), and primary color light B (blue light).
  • the first waveguide module 22 is used to modulate the primary color light G and the primary color light B in the first image light L1.
  • the second waveguide module 23 is used to modulate the primary color light R in the first image light L1.
  • the first waveguide module 22 includes a first waveguide 221 , an in-coupling grating 222 and an out-coupling grating 223 disposed on the same side of the first waveguide 221 .
  • the microdisplay 21 is located on the side of the waveguide 221 away from the coupling-in grating 222 and the coupling-out grating 223 .
  • the first waveguide 221 is used to receive and guide the first image light L1 to the coupling-in grating 222 .
  • the coupling-in grating 222 is used for the first diffraction of the primary color light G and the primary color light B in the first image light L1.
  • the first waveguide 221 and the coupling-in grating 222 are also used to transmit the primary color light R in the first image light L1.
  • the primary color light G and the primary color light B diffracted by the coupling-in grating 222 are incident on the first waveguide 221 , are totally reflected multiple times in the first waveguide 221 , and are guided to the coupling-out grating 223 by the first waveguide 221 .
  • the outcoupling grating 223 includes a diffractive layer 2231 , a connection layer 2232 and an anti-leakage layer 2233 that are stacked in sequence.
  • the diffractive layer 2231 is closer to the first waveguide 221 than the light leakage prevention layer 2233 .
  • the diffractive layer 2231 is used to perform second diffraction on the received primary color light G and primary color light B. Of the primary color light G and primary color light B incident on the diffractive layer 2231, a part of the light is guided back into the first waveguide 221 after being diffracted for the second time, and the other part of the light may exit from the direction toward the light leakage prevention layer 2233.
  • connection layer 2232 is a light-transmitting material, and the light emitted in the direction of the anti-leakage layer 2233 is transmitted through the connection layer 2232 and then reflected back to the diffractive layer 2231 by the anti-leakage layer 2233 to be diffracted by the diffractive layer 2231 and then emitted into the first waveguide 221 .
  • FIG. 7 shows the reflectance of the light leakage preventing layer 2233 to the primary color light G and the primary color light B.
  • the first waveguide 221 is also used for emitting the primary color light G and the primary color light B after being diffracted twice.
  • the second waveguide module 23 includes a second waveguide 231 , an in-coupling grating 232 and an out-coupling grating 233 disposed on the same side of the second waveguide 231 .
  • the second waveguide 231 is used for receiving the primary color light R transmitted from the first waveguide module 22 and for guiding the primary color light R to the coupling-in grating 232 .
  • the coupling-in grating 232 is used for the first diffraction of the primary color light R. As shown in FIG.
  • the primary color light R diffracted by the coupling-in grating 232 enters the second waveguide 231 , is totally reflected multiple times in the second waveguide 231 , and is guided to the coupling-out grating 233 by the second waveguide 231 .
  • the outcoupling grating 233 includes a diffractive layer 2331 , a connection layer 2332 and an anti-leakage layer 2333 stacked in sequence.
  • the diffractive layer 2331 is closer to the second waveguide 231 than the light leakage prevention layer 2333 .
  • the diffractive layer 2331 is used to perform second diffraction on the received primary color light R. Of the primary color light R incident on the diffractive layer 2331 , a part of the light is guided back into the second waveguide 231 after being diffracted for the second time, and another part of the light may exit from a direction toward the light leakage prevention layer 2333 .
  • the connecting layer 2332 is a light-transmitting material, and the light emitted in the direction of the anti-leakage layer 2333 is transmitted through the connecting layer 2332 and then reflected back to the diffractive layer 2331 by the anti-leakage layer 2333 to be diffracted by the diffractive layer 2331 and then exit into the second waveguide 231 .
  • FIG. 8 shows the reflectance of the light leakage preventing layer 2333 to the primary color light R. As shown in FIG.
  • the second waveguide 231 is also used for guiding the primary color light R after twice diffraction to the first waveguide module 22 .
  • the first waveguide module 22 is used to guide the primary color light R, the primary color light G, and the primary color light B after twice diffraction as the second image light L2 to the human eye 40 to display an AR image.
  • the primary color light R is diffracted by the second waveguide module 23 .
  • the coupling grating 222 also has a certain diffraction effect on the primary color light R, but the coupling grating 222 has a certain diffraction effect on the primary color light G and the primary color light R.
  • the diffraction efficiency of the light B is much greater than that of the primary color light R. Therefore, the diffraction effect of the coupling-in grating 222 on the primary color light R is negligible.
  • the display system 20 in this embodiment can achieve all the beneficial effects of the display system 10 in the first embodiment.
  • the number of primary color lights to be guided by each waveguide module is reduced, and each waveguide module has a better reflection effect on the primary color light guided by it, which is conducive to improving the first
  • the color uniformity of the second image light L2 is also beneficial to increase the field of view of the second image light L2.
  • FIG. 9 is mainly used to illustrate the overall structure of the display system 30, and the specific structure of the waveguide module is not shown
  • the display system 30 of this embodiment is basically the same as the display system 20 of the second embodiment, and the two The main difference is that the display system 30 includes three waveguide modules. The following mainly describes the differences between the third embodiment and the second embodiment.
  • the display system 30 includes a microdisplay 31 , a first waveguide module 32 , a second waveguide module 33 and a third waveguide module 34 .
  • the first waveguide module 32 , the second waveguide module 33 and the third waveguide module 34 are stacked in sequence, and the first waveguide module 32 is closer to the microdisplay 31 than the third waveguide module 34 .
  • the display system 30 further includes a glass frame 35 .
  • the glass frame 35 is located on the periphery of the first waveguide module 32 , the second waveguide module 33 and the third waveguide module 34 , and is used for fixing the first waveguide module 32 , the second waveguide module 33 and the third waveguide module 34 , so as to keep the positions of the first waveguide module 32 , the second waveguide module 33 and the third waveguide module 34 from being displaced from each other.
  • the glass frame 35 has a bearing portion 351 and a bearing portion 352 which are parallel to each other. The bearing portion 351 protrudes between the first waveguide module 32 and the second waveguide module 33 .
  • the thickness of the bearing portion 351 itself creates an air gap 36 between the first waveguide module 32 and the second waveguide module 33 .
  • the bearing portion 352 protrudes between the second waveguide module 33 and the third waveguide module 34 .
  • the thickness of the bearing portion 352 itself creates an air gap 37 between the second waveguide module 33 and the third waveguide module 34 .
  • the air gaps 36 and 37 are less than 0.1 mm wide.
  • the microdisplay 31 is used for emitting the first image light L1.
  • the first waveguide module 32, the second waveguide module 33 and the third waveguide module 34 are located on the optical path of the first image light L1, and are used for receiving and modulating the first image light L1 to generate a second image light L2 and exit.
  • the second image light L2 may be directed into the human eye 40 to show the AR image to the user.
  • the first image light L1 includes three primary color lights with different wavelengths.
  • the three primary color lights include: primary color light R (red light), primary color light G (green light), and primary color light B (blue light).
  • the first waveguide module 32 is used to modulate the primary color light B in the first image light L1.
  • the second waveguide module 33 is used to modulate the primary color light G in the first image light L1.
  • the third waveguide module 34 is used to modulate the primary color light R in the first image light L1.
  • the first waveguide module 32 includes a first waveguide 321 , an in-coupling grating 322 and an out-coupling grating 323 disposed on the same side of the second waveguide 321 .
  • the microdisplay 31 is located on the side of the waveguide 321 away from the coupling-in grating 322 and the coupling-out grating 323 .
  • the first waveguide 321 is used to receive and guide the first image light L1 to the coupling-in grating 322 .
  • the coupling-in grating 322 is used for the first diffraction of the primary color light B in the first image light L1.
  • the first waveguide 321 and the coupling-in grating 322 are also used to transmit the primary color light G and the primary color light R in the first image light L1.
  • the primary color light B diffracted by the coupling-in grating 322 is incident on the first waveguide 321 , is totally reflected multiple times in the first waveguide 321 , and is guided to the coupling-out grating 323 by the first waveguide 321 .
  • the outcoupling grating 323 includes a diffractive layer 3231 , a connection layer 3232 and an anti-leakage layer 3233 which are stacked in sequence.
  • the diffractive layer 3231 is closer to the first waveguide 321 than the light leakage prevention layer 3233 .
  • the diffractive layer 3231 is used for the second diffraction of the received primary color light B. Of the primary color light B incident on the diffractive layer 3231 , a part of the light is guided back into the first waveguide 321 after being diffracted for the second time, and another part of the light may exit from a direction toward the light leakage prevention layer 3233 .
  • connection layer 3232 is a light-transmitting material, and the light emitted in the direction of the anti-leakage layer 3233 is transmitted through the connection layer 3232 and then reflected back to the diffraction layer 3231 by the anti-leakage layer 3233 to be diffracted by the diffraction layer 3231 and then emitted into the first waveguide 321 .
  • the first waveguide 321 is also used for emitting the primary color light B after being diffracted twice.
  • the second waveguide module 33 includes a second waveguide 331 , an in-coupling grating 332 and an out-coupling grating 333 disposed on the same side of the second waveguide 331 .
  • the second waveguide 331 is used for receiving the primary color light G and the primary color light R transmitted from the first waveguide module 32 , and for guiding the primary color light G and the primary color light R to the coupling-in grating 332 .
  • the coupling-in grating 332 is used for the first diffraction of the primary color light G, and is also used for transmitting the primary color light R. As shown in FIG.
  • the primary color light G diffracted by the coupling-in grating 332 enters the second waveguide 331 , is totally reflected multiple times in the second waveguide 331 , and is guided to the coupling-out grating 333 by the second waveguide 331 .
  • the outcoupling grating 333 includes a diffractive layer 3331 , a connection layer 3332 and an anti-leakage layer 3333 that are stacked in sequence.
  • the diffractive layer 3331 is closer to the second waveguide 331 than the anti-leakage layer 3333 .
  • the diffractive layer 3331 is used to perform the second diffraction on the received primary color light G. Of the primary color light G incident on the diffractive layer 3331 , a part of the light is guided back into the second waveguide 331 after being diffracted for the second time, and another part of the light may exit from a direction toward the light leakage prevention layer 3333 .
  • the connecting layer 3332 is a light-transmitting material, and the light emitted in the direction of the anti-leakage layer 3333 is transmitted through the connecting layer 3332 and then reflected back to the diffractive layer 3331 by the anti-leakage layer 3333 to be diffracted by the diffractive layer 3331 and then exit into the second waveguide 331 .
  • the third waveguide module 34 includes a third waveguide 341 , an in-coupling grating 342 and an out-coupling grating 343 disposed on the same side of the third waveguide 341 .
  • the third waveguide 341 is used for receiving the primary color light R transmitted from the second waveguide module 33 and for guiding the primary color light R to the coupling-in grating 342 .
  • the coupling-in grating 342 is used for the first diffraction of the primary color light R. As shown in FIG.
  • the primary color light R diffracted by the coupling-in grating 342 is incident on the third waveguide 341 , is totally reflected multiple times in the third waveguide 341 , and is guided to the coupling-out grating 343 by the third waveguide 341 .
  • the outcoupling grating 343 includes a diffractive layer 3431 , a connection layer 3432 and an anti-leakage layer 3433 stacked in sequence.
  • the diffractive layer 3431 is closer to the third waveguide 341 than the anti-leakage layer 3433 .
  • the diffractive layer 3431 is used for the second diffraction of the received primary color light R. Of the primary color light R incident on the diffractive layer 3431 , a part of the light is guided back into the third waveguide 341 after being diffracted for the second time, and another part of the light may exit from a direction toward the light leakage prevention layer 3433 .
  • the connecting layer 3432 is a light-transmitting material, and the light emitted in the direction of the anti-leakage layer 3433 is transmitted through the connecting layer 3432 and then reflected back to the diffractive layer 3431 by the anti-leakage layer 3433 to be diffracted by the diffractive layer 3431 and then exit into the third waveguide 341 .
  • the second waveguide 331 is also used for guiding the primary color light G after twice diffraction to the first waveguide module 32 .
  • the third waveguide 331 is also used to guide the primary color light R after twice diffraction to the first waveguide module 32 .
  • the first waveguide module 32 is used to guide the primary color light R, the primary color light G, and the primary color light B after being diffracted twice as the second image light L2 to the human eye 40 to display an AR image.
  • the first waveguide module 32 diffracts the primary color light B and transmits the primary color light G and R; the second waveguide module 33 diffracts the primary color light G and transmits the primary color light R; The three-waveguide module 34 diffracts.
  • the coupling grating 322 when the primary color light G and the primary color light R pass through the coupling grating 322 in the first waveguide module 32, the coupling grating 322 also has a certain diffraction effect on the primary color light G and the primary color light R, but the coupling grating 322 also has a certain diffraction effect on the primary color light G and the primary color light R.
  • the diffraction efficiency of the grating 322 for the primary color light B is much greater than the diffraction efficiency for the primary color light G and the primary color light B. Therefore, the diffraction effect of the coupling grating 322 on the primary color light G and the primary color light R can be ignored.
  • the coupling grating 332 also has a certain diffraction effect on the primary color light R, but the diffraction efficiency of the coupling grating 332 for the primary color light G is much greater than that for the primary color light G. Diffraction efficiency of primary color light G. Therefore, the diffraction effect of the coupling grating 332 on the primary color light R is also negligible.
  • the display system 30 in this embodiment can achieve all the beneficial effects of the display system 20 in the second embodiment.
  • the number of primary color lights to be guided by each waveguide module is further reduced, and each waveguide module has a better reflection effect on the primary color light guided by it, which is beneficial to Further improving the color uniformity of the second image light L2 is also beneficial to further increase the field of view of the second image light L2.

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Abstract

一种波导模组（12），包括波导（121）、耦入光栅（122）和耦出光栅（123）；波导（121）用于接收并引导第一图像光（L1）至耦入光栅（122）；耦入光栅（122）设置于波导（121）上，用于衍射第一图像光（L1）并引导第一图像光（L1）至波导（121）；波导（121）还用于将第一图像光（L1）引导至耦出光栅（123）；耦出光栅（123）设置于波导（121）上，耦出光栅（123）包括衍射层（1231）、连接层（1232）和防漏光层（1233）；衍射层（1231）固定设置于波导（121）的表面，用于衍射部分第一图像光（L1）；连接层（1232）位于衍射层（1231）和防漏光层（1233）之间，用于固定连接衍射层（1231）和防漏光层（1233）；防漏光层（1233）位于连接层（1232）远离波导（121）的一侧，用于反射另一部分第一图像光（L1），以使另一部分第一图像光（L1）被衍射层（1231）衍射后出射至波导（121）；波导（121）还用于将衍射后的第一图像光（L1）作为第二图像光（L2）出射，第二图像光（L2）用于显示增强现实图像。还提供一种显示***（10）。

Description

波导模组和显示*** 技术领域
本发明涉及增强现实显示技术领域，尤其涉及一种波导模组及应用该波导模组的显示***。
背景技术
增强现实(Augmented Reality,AR)技术被广泛应用于各类场景。其中AR眼镜常被应用于娱乐游戏。AR眼镜包括衍射光波导模组，衍射光波导模组包括波导和出瞳光栅(或称耦出光栅)。出瞳光栅用于基于光栅的衍射效应将接收到的光从波导中耦出进入人眼。由于光栅对光的衍射具有对称性，出瞳光栅处的光线一部分耦出进入人眼，另一部分进入到外界环境中，从而导致漏光问题。一方面，漏光使得光线所展示的信息暴露于外界环境，用户隐私泄露；另一方面，漏光使得AR眼镜被从外部观察时呈现大面积亮光，影响美观；此外，漏光的光量与入人眼的光量在同一数量级，导致波导效率低，增加了功耗。
现有技术中一种解决漏光问题的方式是在出瞳光栅远离波导一侧设置吸收元件，用于吸收漏掉的光，防止其入射至外界环境。但该吸收元件所吸收的光的光量与入射至人眼的光的光量在同一数量级，采用吸收元件时光利用效率较低。且吸收元件为与波导分立的元器件，增设吸收元件会增加装置整体厚度。
现有技术中另一种解决上述问题的方式是在出瞳光栅远离波导的一侧设置镀有反射滤光膜的保护玻璃，防止漏掉的光入射至外界环境。但镀有反射滤光膜的保护玻璃为与波导分立的元器件，增设保护玻璃也会增加装置整体厚度。
发明内容
本申请一方面提供一种波导模组，包括：波导、耦入光栅和耦出光栅；所述波导用于接收并引导第一图像光至所述耦入光栅；所述耦入光栅设置于所述波导上，用于衍射所述第一图像光并引导经衍射后的第一图像光至所述波导；所述波导还用于将所述耦入光栅衍射后的第一图像光引导至所述耦出光栅；所述耦出光栅设置于所述波导上且与所述耦入光栅位于所述波导的同一侧，所述耦出光栅包括衍射层、连接层和防漏光层；所述衍射层固定设置于所述波导的表面，用于衍射部分第一图像光并将衍射后的所述部分第一图像光引导至所述波导；所述连接层位于所述衍射层和所述防漏光层之间，用于固定连接所述衍射层和所述防漏光层；所述防漏光层位于所述连接层远离所述波导的一侧，用于反射朝向远离所述波导的方向从所述衍射层出射的另一部分第一图像光，以使所反射的所述另一部分第一图像光被所述衍射层衍射后出射至所述波导；所述波导还用于将经过所述耦入光栅和所述衍射层衍射后的第一图像光作为第二图像光出射，所述第二图像光用于显示增强现实图像。
上述波导模组，第一方面，通过防漏光层反射第一图像光至衍射层，可对从衍射层远离波导一侧出射的第一图像光进行回收利用，可有效改善波导模组漏光问题，有利于提升显示***美观度，还有利于提升光能利用率。第二方面，连接层位于衍射层和防漏光层之间，进而使得连接层与衍射层可用于共同承载防漏光层，避免另外设置用于承载防漏光层的基底(例 如选用玻璃基底，玻璃基底的厚度在毫米级别)，而连接层厚度在微米数量级(例如在十几微米左右)，因此有利于减小耦出光栅整体的厚度和重量，从而减小显示***整体的厚度和重量。第三方面，连接层起到固定连接的作用，用于将分别位于其两侧的衍射层和防漏光层固定连接为一个整体，使得各层结构(主要指衍射层、连接层和防漏光层)之间更加紧凑，相较于设置分立的元件或模组，有利于减小耦出光栅整体的厚度和重量，从而减小显示***整体的厚度和重量，还有利于提升显示***整体可靠性。
在一些实施例中，所述防漏光层为反射滤光膜。
在一些实施例中，所述防漏光层为反射体光栅。
在一些实施例中，所述反射体光栅为掺杂有液晶材料的光敏材料。
通过掺杂液晶材料，有利于提升防漏光层的折射率调制度，折射率调制度提升时，要达到相同的折射效果所需的防漏光层的厚度更低，因此，通过掺杂液晶材料有利于减小防漏光层的厚度。
在一些实施例中，所述连接层的折射率不同于所述衍射层的折射率。
从而使得第一图像光可由衍射层透射至连接层，并从连接层透射出去。
在一些实施例中，所述连接层通过镀膜的方式形成。
在一些实施例中，所述连接层固定连接所述防漏光层的表面与所述衍射层固定连接所述连接层的表面之间具有最小垂直距离d，0nm≤d≤10μm。
连接层的厚度在微米数量级，有利于减小衍射模组的厚度和重量。
在一些实施例中，所述连接层固定连接所述防漏光层的表面为连续、平坦的表面，所述连接层固定连接所述防漏光层的表面与所述衍射层固定连接所述连接层的表面之间具有最小垂直距离d，0nm＜d≤10μm。
如此，连接层位于衍射层和防漏光层之间，起到平坦衍射层的作用，进而使得连接层可用于承载防漏光层，避免另外设置用于承载防漏光层的基底(例如选用玻璃基底，玻璃基底的厚度在毫米级别)，而连接层厚度在微米数量级(例如在十几微米左右)，因此有利于减小耦出光栅整体的厚度和重量，从而减小显示***整体的厚度和重量。
在一些实施例中，所述第一图像光中包括波长互不相同的多种基色光；
所述耦入光栅和所述衍射层用于对第一图像光中的至少一种基色光进行衍射。
所述耦入光栅和所述衍射层对所有基色光进行衍射时，有利于减小所述耦入光栅和所述衍射层厚度；所述耦入光栅和所述衍射层对第一图像光中其中一种或几种基色光进行衍射时，需要更多层的波导模组，多层的波导模组分别对第一图像光中的各个基色光进行衍射，有利于提升第二图像光的颜色均匀性和增大第二图像光的视场。
在一些实施例中，所述耦入光栅所衍射的基色光与所述衍射层所衍射的基色光相同。
本申请另一方面提供一种波导模组，包括第一波导、第一耦入光栅、第一耦出光栅、第二波导、第二耦入光栅及第二耦出光栅；所述第一耦入光栅和所述第一耦出光栅设置于所述第一波导的同一侧，所述第一波导用于接收包括三种基色光的第一图像光，所述第一波导用于引导至少一基色光至所述第一耦入光栅，并引导其余基色光至所述第二波导；所述第一耦入光栅用于对所述至少一基色光进行衍射，并用于引导衍射后的所述至少一基色光至所述第一波导；所述第一波导还用于将所述第一耦入光栅衍射后的所述至少一基色光引导至所述第一耦出光栅；所述第一耦出光栅包括第一衍射层、第一连接层和第一防漏光层；所述第一衍射层固定设置于所述第一波导的表面，用于衍射部分至少一基色光并将衍射后的所述部分至少 一基色光引导至所述第一波导；所述第一连接层位于所述第一衍射层和所述第一防漏光层之间，用于固定连接所述第一衍射层和所述第一防漏光层；所述第一防漏光层位于所述第一连接层远离所述第一波导的一侧，用于反射朝向远离所述第一波导的方向从所述第一衍射层出射的另一部分至少一基色光，以使所反射的所述另一部分至少一基色光被所述第一衍射层衍射后出射至所述第一波导；所述第二耦入光栅和所述第二耦出光栅设置于所述第二波导的同一侧，所述第二波导用于接收并引导所述其余基色光至所述第二耦入光栅；所述第二耦入光栅用于对所述其余基色光进行衍射，并用于引导衍射后的所述其余基色光至所述第二波导；所述第二波导还用于将所述第二耦入光栅衍射后的所述其余基色光引导至所述第二耦出光栅；所述第二耦出光栅包括第二衍射层、第二连接层和第二防漏光层；所述第二衍射层固定设置于所述第二波导的表面，用于衍射部分所述其余基色光并将衍射后的所述部分其余基色光引导至所述第二波导；所述第二连接层位于所述第二衍射层和所述第二防漏光层之间，用于固定连接所述第二衍射层和所述第二防漏光层；所述第二防漏光层位于所述第二连接层远离所述第二波导的一侧，用于反射朝向远离所述第二波导的方向从所述第二衍射层出射的另一部分其余基色光，以使所反射的所述另一部分其余基色光被所述第二衍射层衍射后出射至所述第一波导；所述第一波导还用于将经过所述第一耦入光栅、所述第一衍射层、所述第二耦入光栅及所述第二衍射层衍射后的第一图像光作为第二图像光出射，所述第二图像光用于显示增强现实图像。
上述的波导模组，通过增加波导、耦入光栅和耦出光栅的数量，使得每个波导需要引导的基色光的数量减少，则每个波导对其引导的基色光的反射效果更好，有利于提高第二图像光的颜色均匀性，还有利于增大第二图像光的视场。
在一些实施例中，波导模组还包括第三波导、第三耦入光栅及第三耦出光栅，所述第一图像光包括第一基色光、第二基色光及第三基色光；所述第一波导用于引导所述第一基色光至所述第一耦入光栅，并引导所述第二基色光和所述第三基色光至所述第二波导；所述第一耦入光栅和所述第一衍射层用于衍射所述第一基色光；所述第二波导用于引导所述第二基色光至所述第二耦入光栅，并引导所述第三基色光至所述第三波导；所述第二耦入光栅和所述第二衍射层用于衍射所述第二基色光；所述第三耦入光栅和所述第三耦出光栅设置于所述第三波导的同一侧，所述第三波导用于引导所述第三基色光至所述第三耦入光栅，所述第三耦入光栅用于对所述第三基色光进行衍射，并用于引导衍射后的所述第三基色光至所述第三波导；所述第三波导还用于将所述第三耦入光栅衍射后的所述第三基色光引导至所述第三耦出光栅；所述第三耦出光栅包括第三衍射层、第三连接层和第三防漏光层；所述第三衍射层固定设置于所述第三波导的表面，用于衍射部分所述第三基色光并将衍射后的所述部分第三基色光引导至所述第三波导；所述第三连接层位于所述第三衍射层和所述第三防漏光层之间，用于固定连接所述第三衍射层和所述第三防漏光层；所述第三防漏光层位于所述第三衍射层远离所述第三波导的一侧，用于反射朝向远离所述第三波导的方向从所述第三衍射层出射的另一部分第三基色光，以使所反射的所述另一部分第三基色光被所述第三衍射层衍射后出射至所述第一波导；所述第一波导还用于将经过所述第一耦入光栅、所述第一衍射层、所述第二耦入光栅、所述第二衍射层、所述第三耦入光栅及所述第三衍射层衍射后的第一图像光作为第二图像光出射，所述第二图像光用于显示增强现实图像。
上述的波导模组，通过增加波导、耦入光栅和耦出光栅的数量，使得每个波导需要引导的基色光的数量减少，则每个波导对其引导的基色光的反射效果更好，有利于提高第二图像 光的颜色均匀性，还有利于增大第二图像光的视场。
本申请另一方面提供一种显示***，包括：微显示器，用于发射第一图像光；以及至少一波导模组，位于所述第一图像光的光路上，每一波导模组为如上述任一项所述的波导模组。
上述显示***，第一方面，通过防漏光层反射第一图像光至衍射层，可对从衍射层远离波导一侧出射的第一图像光进行回收利用，可有效改善波导模组漏光问题，有利于提升显示***美观度，还有利于提升光能利用率。第二方面，连接层位于衍射层和防漏光层之间，进而使得连接层与衍射层可用于共同承载防漏光层，避免另外设置用于承载防漏光层的基底(例如选用玻璃基底，玻璃基底的厚度在毫米级别)，而连接层厚度在微米数量级(例如在十几微米左右)，因此有利于减小耦出光栅整体的厚度和重量，从而减小显示***整体的厚度和重量。第三方面，连接层起到固定连接的作用，用于将分别位于其两侧的衍射层和防漏光层固定连接为一个整体，使得各层结构(主要指衍射层、连接层和防漏光层)之间更加紧凑，相较于设置分立的元件或模组，有利于减小耦出光栅整体的厚度和重量，从而减小显示***整体的厚度和重量，还有利于提升显示***整体可靠性。
附图说明
图1A为本申请实施例一中显示***的一结构示意图。
图1B为本申请实施例一中显示***的另一结构示意图。
图2为图1A所示显示***中的光路结构示意图。
图3为第一图像光的光谱分布示意图。
图4为图2中防漏光层对第一图像光中各个基色光的反射率示意图。
图5为本申请实施例二中显示***的结构示意图。
图6为本申请实施例二中显示***中的光路结构示意图。
图7为图6中第一波导模组对第一图像光中各个基色光的反射率示意图。
图8为图7中第二波导模组对第一图像光中各个基色光的反射率示意图。
图9为本申请实施例三中显示***的结构示意图。
图10为本申请实施例三中显示***的结构示意图。
具体实施方式
下面结合本申请实施例中的附图对本申请实施例进行描述。
当增强现实眼镜中采用衍射光波导实现近眼显示时，可以使用本申请的将耦出光栅区域平坦化，并设置防漏光层，从而实现在防止衍射光波导漏光的基础上，减小衍射光波导的厚度与重量。
实施例一
请一并参阅图1A和图1B，本实施例提供一种基于增强现实(Augmented Reality,AR)的显示***10。显示***10可结合真实图像和虚拟图像，以生成AR图像。用户通过穿戴显示***10，显示***10生成的AR图像进入人眼40，用户即可观察到显示***10所生成的AR图像。本实施例中，显示***10为AR眼镜，用户可将AR眼镜佩戴于眼部以观察图像。于其他实施例中，显示***10还可为AR头盔等。
请参阅图2，显示***10包括微显示器11及波导模组12。微显示器11用于出射第一图像光L1。波导模组12用于接收第一图像光L1并对其进行调制，以生成第二图像光L2并出 射。第二图像光L2可被引导进入人眼40，以向用户展示AR图像。
第一图像光L1中包括多种基色光，该多种基色光可相互配合以调制出彩色图像。本实施例中，第一图像光L1中包括波长不同的三种基色光。三种基色光分别为：基色光R(红光)、基色光G(绿光)以及基色光B(蓝光)。波导模组12用于分别对基色光R、基色光G以及基色光B进行调制。
波导模组12包括波导121、设置于波导121上同一侧的耦入光栅122和耦出光栅123。微显示器11位于波导121远离耦入光栅122和耦出光栅123的一侧。
波导模组12位于第一图像光L1的光路上。波导121用于接收第一图像光L1并用于先后引导第一图像光L1至耦入光栅122和耦出光栅123。第一图像光L1入射至波导121后，可被波导121引导至耦入光栅122。耦入光栅122用于对第一图像光L1进行第一次衍射，并将衍射后的第一图像光L1引导至波导121。经耦入光栅122衍射后的第一图像光L1入射至波导121后，在波导121中发生多次全反射，并最终被波导121引导至耦出光栅123。耦出光栅123用于对接收到的第一图像光L1进行第二次衍射并引导至波导121。波导121用于将耦出光栅123引导的光引导至人眼40。由波导121出射并被引导至人眼40的、经过两次衍射后的光定义为上述的第二图像光L2。
耦出光栅123包括衍射层1231、连接层1232以及防漏光层1233。衍射层1231固定设置于波导121表面。连接层1232固定设置于波导121设置该衍射层1231的表面并覆盖该衍射层1231，防漏光层1233位于连接层1232远离衍射层1231的一侧。
衍射层1231为一维或二维衍射光栅，用于对接收到的第一图像光L1中各个基色光分别进行衍射。衍射层1231的光栅周期为100纳米到1000纳米，光栅高度为20纳米到1000纳米，光栅形状可以为矩形、倾斜、闪耀光栅等。衍射层1231可为单层结构或多层结构。衍射层1231为单层结构时，该单层用于对第一图像光L1中所有的基色光进行衍射。衍射层1231包括多层结构时，其中的每一层用于对第一图像光L1中的至少一种基色光进行衍射。例如衍射层1231为三层结构时，每一层用于衍射第一图像光L1中的基色光R、基色光G以及基色光B的其中一种基色光。衍射层1231采用单层结构时，有利于减小整体厚度。衍射层1231采用多层结构时，由于每一层用于衍射其中一种基色光，有利于降低光栅结构复杂度。
衍射层1231对第一图像光L1进行衍射后，将衍射后的第一图像光L1引导至波导121。然而由于制作工艺等原因，入射至衍射层1231的第一图像光L1中一部分光可能朝向衍射层1231远离波导121一侧出射，导致入射至衍射层1231的第一图像光L1无法全部被衍射后再被引导回波导121。
连接层1232为透光材料，例如为二氧化硅、二氧化钛、二氧化锆、聚甲基丙烯酸甲酯(polymethyl methacrylate,PMMA)等。朝向衍射层1231远离波导121一侧出射的第一图像光L1可从连接层1232透射。连接层1232选用雾度较小的材料，本实施例中，连接层1232采用雾度小于0.1的材料，有利于减小第一图像光L1经过连接层1232时的光损失。
衍射层1231对第一图像光L1具有第一折射率，连接层1232对第一图像光L1具有第二折射率。第一折射率不同于第二折射率，以使得衍射层1231与连接层1232之间产生折射率差，从而使得第一图像光L1可由衍射层1231透射至连接层1232，并从连接层1232透射出去。本实施例中，衍射层1231的折射率(也即第一折射率)为1.4到2.6，连接层1232的折射率(也即第二折射率)也为1.4到2.6。第一折射率和第二折射率的数值范围虽相同，但同时应满足上述的形成折射率差的要求。
如上述的，衍射层1231可为矩形光栅、倾斜光栅、闪耀光栅等，其可能具有例如凹槽、狭缝等，也即衍射层1231远离波导121的表面(定义为接触面S1)并非为一连续、平坦的表面。连接层1232覆盖衍射层1231，用于填充接触面S1上不连续、不平坦的区域，且连接层1232远离接触面S1的表面形成为连续、平坦的表面，以便承载和固定连接防漏光层1233。
连接层1232可为通过镀膜、旋涂后烘干等工艺形成的覆盖衍射层1231的薄膜。连接层1232远离衍射层1231的表面与衍射层1231的接触面S1之间具有最小垂直距离d，0nm≤d≤10μm(包括端点)。由于接触面S1可能为凹凸不平的，上述最小垂直距离指接触面S1上距离连接层1232远离衍射层1231的表面最近的点与连接层1232远离衍射层1231的表面之间的垂直距离。
接触面S1为平坦表面时，最小距离d可以等于0nm，连接层1232未覆盖接触面S1，也即接触面S1相对连接层1232裸露，连接层固定连接防漏光层1233的一面和接触面S1皆直接与防漏光层1233接触，且用于共同承载防漏光层1233，此时耦出光栅123的整体厚度较小。接触面S1为凹凸不平的表面时，0nm＜d≤10μm，连接层1232覆盖接触面S1，连接层固定连接防漏光层1233的一面直接与防漏光层1233接触，连接层1232固定连接防漏光层1233的一面对衍射层1231起到平坦的作用，用于承载防漏光层1233，此时连接层1232与防漏光层1233的表面接触面积更大，有利于提升固定效果。
防漏光层1233用于接收并反射从连接层1232入射的第一图像光L1。经防漏光层1233反射的第一图像光L1可重新入射至衍射层1231以被衍射层1231衍射后出射至波导121。防漏光层1233为一层厚度很小(厚度为微米级)的薄膜层，其可通过镀膜的方式直接形成于连接层1232远离衍射层1231的表面。由于连接层1232与防漏光层1233皆为厚度为微米级的薄膜层，两者之间可通过薄膜层之间自然的粘附力进行固定连接。
本实施例中，防漏光层1233为反射滤光膜，其制造工艺较成熟，易实现大批量生产。防漏光层1233包括依次层叠的、折射率互不相同的多层薄膜以及一层金属层，该多层薄膜以及该金属层用于确保对特定的波长和光谱范围具有较高的反射率。
于其他实施例中，防漏光层1233还可为反射体光栅。反射体光栅为光敏材料，例如为光敏树脂。反射体光栅可通过曝光显影的方式形成，由于曝光装置简单，使得防漏光层1233为反射体光栅时，成本较低。反射体光栅的厚度为5微米到1000微米。防漏光层1233为反射体光栅时，可在其中掺杂液晶材料。掺杂液晶材料有利于提升防漏光层1233的折射率调制度。折射率调制度提升时，要达到相同的折射效果所需的防漏光层1233的厚度更低。因此，防漏光层1233为反射体光栅时，通过掺杂液晶材料有利于减小防漏光层1233的厚度。
防漏光层1233为反射体光栅时，可为单层结构或依次层叠的多层结构。防漏光层1233为单层结构时，该单层结构同时对所有的基色光都具备高反射率，有利于减小防漏光层1233整体厚度。防漏光层1233为依次层叠的多层结构时，例如为三层结构，每层结构对第一图像光L1中某一基色光具有高反射率，有利于降低光栅结构复杂度。
请参阅图3，第一图像光L1中的三种基色光的光强相同。基色光R具有中心波长λ R，光谱宽度为Δλ R，光谱范围为633±2nm。基色光G具有中心波长λ G，光谱宽度为Δλ G，光谱范围为532±2nm。基色光B具有中心波长λ B，光谱宽度为Δλ B，光谱范围为450±2nm。
请参阅图4，防漏光层1233对各个基色光的反射率相同，且对波长为λ R、λ G、λ B的光的反射率为100％。
经耦入光栅122和耦出光栅123衍射后，第一图像光L1的视场被扩大，因此第二图像光 L2的视场面积大于第一图像光L1的视场面积。
本实施例中，第一方面，通过防漏光层1233反射第一图像光L1至衍射层1231，可对从衍射层1231远离波导121一侧出射的第一图像光L1进行回收利用，可有效改善波导模组12漏光问题，有利于提升显示***10美观度，还有利于提升光能利用率。第二方面，连接层1232位于衍射层1231和防漏光层1233之间，连接层1232起到平坦衍射层1231的接触面S1的作用，进而使得连接层1232可用于承载防漏光层1233，避免另外设置用于承载防漏光层1233的基底(例如选用玻璃基底，玻璃基底的厚度在毫米级别)，而连接层1232厚度在微米数量级(例如在十几微米左右)，因此有利于减小耦出光栅123整体的厚度和重量，从而减小显示***10整体的厚度和重量。第三方面，连接层1232起到固定连接的作用，用于将分别位于其两侧的衍射层1231和防漏光层1233固定连接为一个整体，使得各层结构(主要指衍射层1231、连接层1232和防漏光层1233)之间更加紧凑，相较于设置分立的元件或模组，有利于减小耦出光栅123整体的厚度和重量，从而减小显示***10整体的厚度和重量，还有利于提升显示***10整体可靠性。
实施例二
请参阅图5(图5主要用于示意显示***20的整体架构，未展示波导模组的具体结构)，本实施例提供的显示***20，与实施例一中的显示***10基本相同，两者之间的区别主要在于：显示***20包括两个波导模组。以下主要对实施例二与实施例一的区别部分进行说明。
本实施例中，显示***20包括微显示器21、第一波导模组22和第二波导模组23。第一波导模组22和第二波导模组23相互层叠，且第一波导模组22位于微显示器21和第二波导模组23之间。
本实施例中，显示***20还包括玻璃框架24。玻璃框架24位于第一波导模组22和第二波导模组23的***，用于固定第一波导模组22和第二波导模组23，以保持第一波导模组22和第二波导模组23相互位置不发生偏移。玻璃框架24具有一承载部241，承载部241凸伸入第一波导模组22和第二波导模组23之间。承载部241本身的厚度使得第一波导模组22和第二波导模组23之间产生一空气间隙25。空气间隙25宽度小于0.1毫米。
微显示器21用于出射第一图像光L1。第一波导模组22和第二波导模组23位于第一图像光L1的光路上，用于接收第一图像光L1并对其进行调制，以生成第二图像光L2并出射。第二图像光L2可被引导进入人眼40，以向用户展示AR图像。
请参阅图6，第一图像光L1中包括波长不同的三种基色光。三种基色光包括：基色光R(红光)、基色光G(绿光)以及基色光B(蓝光)。第一波导模组22用于调制第一图像光L1中的基色光G和基色光B。第二波导模组23用于调制第一图像光L1中的基色光R。
第一波导模组22包括第一波导221、设置于第一波导221上同一侧的耦入光栅222和耦出光栅223。微显示器21位于波导221远离耦入光栅222和耦出光栅223的一侧。
第一波导221用于接收并引导第一图像光L1至耦入光栅222。耦入光栅222用于对第一图像光L1中的基色光G和基色光B进行第一次衍射。第一波导221和耦入光栅222还用于透射第一图像光L1中的基色光R。经耦入光栅222衍射后的基色光G和基色光B入射至第一波导221，在第一波导221中被多次全反射，并被第一波导221引导至耦出光栅223。
耦出光栅223包括依次层叠的衍射层2231、连接层2232及防漏光层2233。其中衍射层2231相较于防漏光层2233更靠近第一波导221。衍射层2231用于对接收到的基色光G和基色光B进行第二次衍射。入射至衍射层2231的基色光G和基色光B中，一部分光被第二次 衍射后引导回第一波导221中，另一部分光可能从朝向防漏光层2233的方向出射。连接层2232为透光材料，朝向防漏光层2233的方向出射的光从连接层2232透射后被防漏光层2233反射回衍射层2231，以被衍射层2231衍射后出射至第一波导221中。图7示出了防漏光层2233对基色光G和基色光B的反射率。第一波导221还用于出射经两次衍射后的基色光G和基色光B。
第二波导模组23包括第二波导231、设置于第二波导231上同一侧的耦入光栅232和耦出光栅233。
第二波导231用于接收从第一波导模组22透射的基色光R，并用于引导基色光R至耦入光栅232。耦入光栅232用于对基色光R进行第一次衍射。经耦入光栅232衍射后的基色光R入射至第二波导231，在第二波导231中被多次全反射，并被第二波导231引导至耦出光栅233。
耦出光栅233包括依次层叠的衍射层2331、连接层2332及防漏光层2333。其中衍射层2331相较于防漏光层2333更靠近第二波导231。衍射层2331用于对接收到的基色光R进行第二次衍射。入射至衍射层2331的基色光R中，一部分光被第二次衍射后引导回第二波导231中，另一部分光可能从朝向防漏光层2333的方向出射。连接层2332为透光材料，朝向防漏光层2333的方向出射的光从连接层2332透射后被防漏光层2333反射回衍射层2331，以被衍射层2331衍射后出射至第二波导231中。图8示出了防漏光层2333对基色光R的反射率。
第二波导231还用于引导经两次衍射后的基色光R至第一波导模组22。第一波导模组22用于将经两次衍射后的基色光R、基色光G及基色光B作为第二图像光L2引导至人眼40，以展示AR图像。
本实施例中，虽然上述描述了第一波导模组22衍射基色光G和基色光B，并透射基色光R，基色光R由第二波导模组23衍射。但实际产品中，基色光R在经过第一波导模组22中的耦入光栅222时，耦入光栅222对基色光R也具有一定的衍射作用，但耦入光栅222对基色光G和基色光B的衍射效率远大于对基色光R的衍射效率。因此耦入光栅222对基色光R的衍射作用可忽略不计。
本实施例中的显示***20，可以实现如实施例一中显示***10的所有有益效果。在此基础上，通过增加波导模组的数量，使得每个波导模组需要引导的基色光的数量减少，则每个波导模组对其引导的基色光的反射效果更好，有利于提高第二图像光L2的颜色均匀性，还有利于增大第二图像光L2的视场。
实施例三
请参阅图9(图9主要用于示意显示***30的整体架构，未展示波导模组的具体结构)，本实施例的显示***30，与实施例二中的显示***20基本相同，两者之间的区别主要在于：显示***30包括三个波导模组。以下主要对实施例三与实施例二的区别部分进行说明。
本实施例中，显示***30包括微显示器31、第一波导模组32、第二波导模组33及第三波导模组34。第一波导模组32、第二波导模组33及第三波导模组34依次层叠，且第一波导模组32相较于第三波导模组34更靠近微显示器31。
本实施例中，显示***30还包括玻璃框架35。玻璃框架35位于第一波导模组32、第二波导模组33和第三波导模组34的***，用于固定第一波导模组32、第二波导模组33和第三波导模组34，以保持第一波导模组32、第二波导模组33和第三波导模组34相互位置不发 生偏移。玻璃框架35具有相互平行的承载部351和承载部352。承载部351凸伸入第一波导模组32和第二波导模组33之间。承载部351本身的厚度使得第一波导模组32和第二波导模组33之间产生一空气间隙36。承载部352凸伸入第二波导模组33和第三波导模组34之间。承载部352本身的厚度使得第二波导模组33和第三波导模组34之间产生一空气间隙37。空气间隙36和37宽度小于0.1毫米。
微显示器31用于出射第一图像光L1。第一波导模组32、第二波导模组33及第三波导模组34位于第一图像光L1的光路上，用于接收第一图像光L1并对其进行调制，以生成第二图像光L2并出射。第二图像光L2可被引导进入人眼40，以向用户展示AR图像。
请参阅图10，第一图像光L1中包括波长不同的三种基色光。三种基色光包括：基色光R(红光)、基色光G(绿光)以及基色光B(蓝光)。第一波导模组32用于调制第一图像光L1中的基色光B。第二波导模组33用于调制第一图像光L1中的基色光G。第三波导模组34用于调制第一图像光L1中的基色光R。
第一波导模组32包括第一波导321、设置于第二波导321上同一侧的耦入光栅322和耦出光栅323。微显示器31位于波导321远离耦入光栅322和耦出光栅323的一侧。
第一波导321用于接收并引导第一图像光L1至耦入光栅322。耦入光栅322用于对第一图像光L1中的基色光B进行第一次衍射。第一波导321和耦入光栅322还用于透射第一图像光L1中的基色光G和基色光R。经耦入光栅322衍射后的基色光B入射至第一波导321，在第一波导321中被多次全反射，并被第一波导321引导至耦出光栅323。
耦出光栅323包括依次层叠的衍射层3231、连接层3232及防漏光层3233。其中衍射层3231相较于防漏光层3233更靠近第一波导321。衍射层3231用于对接收到的基色光B进行第二次衍射。入射至衍射层3231的基色光B中，一部分光被第二次衍射后引导回第一波导321中，另一部分光可能从朝向防漏光层3233的方向出射。连接层3232为透光材料，朝向防漏光层3233的方向出射的光从连接层3232透射后被防漏光层3233反射回衍射层3231，以被衍射层3231衍射后出射至第一波导321中。第一波导321还用于出射经两次衍射后的基色光B。
第二波导模组33包括第二波导331、设置于第二波导331上同一侧的耦入光栅332和耦出光栅333。
第二波导331用于接收从第一波导模组32透射的基色光G和基色光R，并用于引导基色光G和基色光R至耦入光栅332。耦入光栅332用于对基色光G进行第一次衍射，还用于透射基色光R。经耦入光栅332衍射后的基色光G入射至第二波导331，在第二波导331中被多次全反射，并被第二波导331引导至耦出光栅333。
耦出光栅333包括依次层叠的衍射层3331、连接层3332及防漏光层3333。其中衍射层3331相较于防漏光层3333更靠近第二波导331。衍射层3331用于对接收到的基色光G进行第二次衍射。入射至衍射层3331的基色光G中，一部分光被第二次衍射后引导回第二波导331中，另一部分光可能从朝向防漏光层3333的方向出射。连接层3332为透光材料，朝向防漏光层3333的方向出射的光从连接层3332透射后被防漏光层3333反射回衍射层3331，以被衍射层3331衍射后出射至第二波导331中。
第三波导模组34包括第三波导341、设置于第三波导341上同一侧的耦入光栅342和耦出光栅343。
第三波导341用于接收从第二波导模组33透射的基色光R，并用于引导基色光R至耦 入光栅342。耦入光栅342用于对基色光R进行第一次衍射。经耦入光栅342衍射后的基色光R入射至第三波导341，在第三波导341中被多次全反射，并被第三波导341引导至耦出光栅343。
耦出光栅343包括依次层叠的衍射层3431、连接层3432及防漏光层3433。其中衍射层3431相较于防漏光层3433更靠近第三波导341。衍射层3431用于对接收到的基色光R进行第二次衍射。入射至衍射层3431的基色光R中，一部分光被第二次衍射后引导回第三波导341中，另一部分光可能从朝向防漏光层3433的方向出射。连接层3432为透光材料，朝向防漏光层3433的方向出射的光从连接层3432透射后被防漏光层3433反射回衍射层3431，以被衍射层3431衍射后出射至第三波导341中。
第二波导331还用于引导经两次衍射后的基色光G至第一波导模组32。第三波导331还用于引导经两次衍射后的基色光R至第一波导模组32。第一波导模组32用于将经两次衍射后的基色光R、基色光G及基色光B作为第二图像光L2引导至人眼40，以展示AR图像。
本实施例中，虽然上述描述了第一波导模组32衍射基色光B，并透射基色光G和R；第二波导模组33衍射基色光G，并透射基色光R；基色光R由第三波导模组34衍射。但实际产品中，基色光G和基色光R在经过第一波导模组32中的耦入光栅322时，耦入光栅322对基色光G和基色光R也具有一定的衍射作用，但耦入光栅322对基色光B的衍射效率远大于对基色光G和基色光B的衍射效率。因此耦入光栅322对基色光G和基色光R的衍射作用可忽略不计。且基色光R在经过第二波导模组33中的耦入光栅332时，耦入光栅332对基色光R也具有一定的衍射作用，但耦入光栅332对基色光G的衍射效率远大于对基色光G的衍射效率。因此耦入光栅332对基色光R的衍射作用也可忽略不计。
本实施例中的显示***30，可以实现如实施例二中显示***20的所有有益效果。在此基础上，通过进一步增加波导模组的数量，使得每个波导模组需要引导的基色光的数量进一步减少，则每个波导模组对其引导的基色光的反射效果更好，有利于进一步提高第二图像光L2的颜色均匀性，还有利于进一步增大第二图像光L2的视场。
本技术领域的普通技术人员应当认识到，以上的实施方式仅是用来说明本发明，而并非用作为对本发明的限定，只要在本发明的实质精神范围之内，对以上实施例所作的适当改变和变化都落在本发明要求保护的范围之内。

Claims (12)

  1. 一种波导模组，其特征在于，包括：波导、耦入光栅和耦出光栅；
    所述波导用于接收并引导第一图像光至所述耦入光栅；
    所述耦入光栅设置于所述波导上，用于衍射所述第一图像光并引导经衍射后的第一图像光至所述波导；
    所述波导还用于将所述耦入光栅衍射后的第一图像光引导至所述耦出光栅；
    所述耦出光栅设置于所述波导上且与所述耦入光栅位于所述波导的同一侧，所述耦出光栅包括衍射层、连接层和防漏光层；
    所述衍射层固定设置于所述波导的表面，用于衍射部分第一图像光并将衍射后的所述部分第一图像光引导至所述波导；
    所述连接层位于所述衍射层和所述防漏光层之间，用于固定连接所述衍射层和所述防漏光层；
    所述防漏光层位于所述连接层远离所述波导的一侧，用于反射朝向远离所述波导的方向从所述衍射层出射的另一部分第一图像光，以使所反射的所述另一部分第一图像光被所述衍射层衍射后出射至所述波导；
    所述波导还用于将经过所述耦入光栅和所述衍射层衍射后的第一图像光作为第二图像光出射，所述第二图像光用于显示增强现实图像。
  2. 如权利要求1所述的波导模组，其特征在于，所述防漏光层为反射滤光膜。
  3. 如权利要求1所述的波导模组，其特征在于，所述防漏光层为反射体光栅。
  4. 如权利要求3所述的波导模组，其特征在于，所述反射体光栅为掺杂有液晶材料的光敏材料。
  5. 如权利要求1～4任一项所述的波导模组，其特征在于，所述连接层的折射率不同于所述衍射层的折射率。
  6. 如权利要求1～4任一项所述的波导模组，其特征在于，所述连接层通过镀膜的方式形成。
  7. 如权利要求1～4任一项所述的波导模组，其特征在于，所述连接层固定连接所述防漏光层的表面与所述衍射层固定连接所述连接层的表面之间具有最小垂直距离d，0nm≤d≤10μm。
  8. 如权利要求1～4任一项所述的波导模组，其特征在于，所述连接层固定连接所述防漏光层的表面为连续、平坦的表面。
  9. 如权利要求8所述的波导模组，其特征在于，所述连接层固定连接所述防漏光层的表面与所述衍射层固定连接所述连接层的表面之间具有最小垂直距离d，0nm＜d≤10μm。
  10. 如权利要求1～4任一项所述的波导模组，其特征在于，所述第一图像光中包括波长互不相同的多种基色光；
    所述耦入光栅和所述衍射层用于对第一图像光中的至少一种基色光进行衍射。
  11. 如权利要求10所述的波导模组，其特征在于，所述耦入光栅所衍射的基色光与所述衍射层所衍射的基色光相同。
  12. 一种显示***，其特征在于，包括：
    微显示器，用于发射第一图像光；以及
    至少一波导模组，位于所述第一图像光的光路上，每一波导模组为如权利要求1～11任一 项所述的波导模组。
PCT/CN2021/140976 2021-01-29 2021-12-23 波导模组和显示*** WO2022161056A1 (zh)

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