WO2024093348A1 - 一种导光器件以及可穿戴设备 - Google Patents

一种导光器件以及可穿戴设备 Download PDF

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Publication number
WO2024093348A1
WO2024093348A1 PCT/CN2023/106502 CN2023106502W WO2024093348A1 WO 2024093348 A1 WO2024093348 A1 WO 2024093348A1 CN 2023106502 W CN2023106502 W CN 2023106502W WO 2024093348 A1 WO2024093348 A1 WO 2024093348A1
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Prior art keywords
coupling
region
light
waveguide substrate
refractive index
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PCT/CN2023/106502
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English (en)
French (fr)
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程鑫
魏如东
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歌尔光学科技有限公司
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Publication of WO2024093348A1 publication Critical patent/WO2024093348A1/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
    • 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
    • G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • 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
    • G02B6/02—Optical fibres with cladding with or without a coating
    • 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
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/028—Optical fibres with cladding with or without a coating with core or cladding having graded refractive index
    • 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
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements

Definitions

  • the present application relates to the field of near-eye display technology, and more specifically, to a light guide device and a wearable device.
  • Diffractive optical waveguides are the core of augmented reality (AR) devices.
  • AR augmented reality
  • a single refractive index waveguide substrate design is usually adopted, and this solution has many defects in practical applications, such as the rainbow effect in the outcoupling area and the reduced light efficiency caused by backcoupling in the coupling area, which will affect the picture display performance of the augmented reality (AR) device, thereby affecting the user's visual experience and immersive experience.
  • the rainbow effect in the outcoupling area is a very obvious drawback of the current diffractive optical waveguide design, but as far as current technology is concerned, the effect can only be reduced as much as possible through new designs/improvements to the grating structure on the waveguide substrate, but the effect is not ideal.
  • the purpose of this application is to provide a new technical solution for a light-guiding device and a wearable device.
  • an embodiment of the present application provides a light guide device.
  • the light guide device includes a waveguide substrate and an incoupling region and an outcoupling region provided on the waveguide substrate;
  • the waveguide substrate comprises at least two different refractive indices
  • the coupling-in region is used to couple incident light into the waveguide substrate
  • the waveguide substrate is used to totally reflect the incident light and propagate it to the outcoupling region, and different light beams in the incident light can have the same or similar light propagation path lengths after being reflectively modulated by different refractive indices in the waveguide substrate;
  • the outcoupling region is used to outcouple the light beam propagating to the outcoupling region.
  • the coupling-in region is located at a high refractive index region with the highest refractive index on the waveguide substrate.
  • a region, a gradient distribution of a refractive index decreasing from the coupling region to a direction away from the coupling region is formed on the waveguide substrate.
  • the waveguide substrate is a single-layer structure with a gradient refractive index.
  • the waveguide substrate is a stacked structure of two or more layers made of materials with different refractive indices, wherein each material can form at least one layer on the waveguide substrate and make the waveguide substrate have a refractive index, so that the waveguide substrate forms a gradient distribution of refractive index that changes gradually layer by layer.
  • the coupling-in region is located on at least one surface of the waveguide substrate.
  • a gradient distribution is formed on the waveguide substrate along its thickness direction, with the refractive index gradually decreasing from the surface where the coupling-in region is disposed to the other surface opposite thereto.
  • a gradient distribution of refractive index gradually decreasing from the surfaces on both sides to the middle region is formed on the waveguide substrate along its thickness direction.
  • the coupling-in region is located on a side surface of the waveguide substrate, the side surface is an inclined surface or a plane, and a gradient distribution of a decreasing refractive index is formed on the waveguide substrate from the coupling-in region to a direction away from the coupling-in region;
  • a coupling prism is arranged on one side of the coupling region.
  • the incident light includes at least a first light beam and a second light beam.
  • the first light beam can penetrate the interface and enter the low refractive index region, and after being reflected and modulated by the low refractive index region, it propagates to the interface and transmits into the high refractive index region, so that the light propagation path length of the first light beam after a total reflection in the waveguide substrate is the same as or close to the light propagation path length of the second light beam after a total reflection in the waveguide substrate.
  • the coupling-in region and the coupling-out region are provided with a single diffractive optical element or a diffractive optical component composed of a plurality of diffractive optical elements.
  • the coupling-in region and the coupling-out region are provided with diffractive optical elements
  • the diffractive optical elements include one or more of a surface relief grating, a volume holographic grating, a liquid crystal grating and a photonic crystal. kind.
  • the coupling-in region and the coupling-out region are located on the same side of the waveguide substrate; or,
  • the coupling-in region and the coupling-out region are arranged on different sides of the waveguide substrate.
  • the incident light comprises at least two light beams of the same wavelength incident on the coupling region at different incident angles;
  • the incident light is a multi-wavelength light including at least two light beams with different wavelengths, and the light beams with different wavelengths are incident on the coupling region at the same incident angle.
  • an embodiment of the present application provides a wearable device.
  • the wearable device includes:
  • the light guide device according to the first aspect.
  • An optical machine is used to inject the incident light or image into the coupling-in area on the light-guiding component.
  • the embodiment of the present application provides an optical waveguide design scheme.
  • a waveguide substrate with different refractive indices it can be used to correct the light path length of a partial light beam coupled into the waveguide substrate for total reflection propagation, so that each light beam coupled into the waveguide substrate for one total reflection propagation can have the same or similar light propagation path length.
  • This can effectively avoid the occurrence of rainbow effects in the decoupling area and light leakage (backcoupling) in the coupling area, which is beneficial to improving the light efficiency and imaging quality.
  • FIG1 is a schematic diagram of a structure of a light guide device according to an embodiment of the present application.
  • FIG2 is a second schematic structural diagram of a light guide device according to an embodiment of the present application.
  • FIG3 is a schematic diagram of a light propagation path of an existing diffraction optical waveguide
  • FIG4 is a second schematic diagram of the light propagation path of the existing diffraction light waveguide
  • FIG5 is a third schematic diagram of the light propagation path of the existing diffraction light waveguide
  • FIG6 is a fourth schematic diagram of the light propagation path of the existing diffraction light waveguide
  • FIG7 is a schematic diagram of a light propagation path of a light guide device according to an embodiment of the present application.
  • FIG. 8 is a second schematic diagram of the light propagation path of the light guide device according to an embodiment of the present application.
  • Waveguide substrate 11. High refractive index layer; 12. Low refractive index layer; 2. Incoupling region; 3. Outcoupling region; 01. Incident light; 011, first light beam; 012, second light beam; 001, substrate; 002, coupling-in grating.
  • AR head-mounted display devices are taken as an example.
  • AR head-mounted display devices usually include a micro display screen and an optical module.
  • Commonly used optical elements in the optical module of AR head-mounted display devices include prisms, free-form lenses, and optical waveguide devices.
  • optical waveguide devices include geometric optical waveguides and diffraction optical waveguides. Due to the good optical properties of diffraction optical waveguides, they have been widely used in AR devices.
  • a light guiding device is provided.
  • the light guiding device is, for example, an optical waveguide device.
  • the optical waveguide device is, for example, a diffraction optical waveguide.
  • the light-guiding device provided in the embodiments of the present application can be applied to head-mounted display devices, such as AR smart glasses, AR helmets, etc., and can enable users to obtain a better immersive visual experience.
  • head-mounted display devices such as AR smart glasses, AR helmets, etc.
  • the light-guiding device provided in the embodiment of the present application, referring to Figures 1 and 2, as well as Figures 7 and 8, comprises a waveguide substrate 1 and a coupling-in region 2 and a coupling-out region 3 arranged on the waveguide substrate 1; wherein the waveguide substrate 1 comprises at least two different refractive indices; the coupling-in region 2 is used to couple the incident light 01 into the waveguide substrate 1; the waveguide substrate 1 is used to propagate the incident light 01 to the coupling-out region 3 by total reflection, and different light beams in the incident light 01 can have the same or similar light propagation path lengths after being reflectively modulated by different refractive indices in the waveguide substrate 1; the coupling-out region 3 is used to couple out the light beams propagated to the coupling-out region 3.
  • the substrate of a traditional diffraction optical waveguide is usually made of a material with the same refractive index. Based on the dispersion effect of the coupling-in grating thereon, different light beams in the incident light will have different transmission channels after entering the substrate through the coupling-in grating, that is, different light beams will be totally reflected in the substrate at different total reflection angles and propagate to the coupling-out grating. This will cause obvious differences in the light propagation path lengths of different light beams during a single total reflection propagation in the substrate, causing a rainbow effect in the human eye when the coupling-out grating couples the light. In addition, the light beam may also produce light leakage (Backcoupling) at the coupling-in grating, and these phenomena will reduce the light efficiency and affect the imaging quality, thereby affecting the user's viewing experience.
  • Backcoupling light leakage
  • the light source can emit an incident light 01
  • the incident light 01 is, for example, RGB three-color light, that is, the incident light 01 includes, for example, a red light beam R, a blue light beam B, and a green light beam G, wherein the wavelength of the blue light beam B is the shortest, and the wavelength of the red light beam R is the longest.
  • the incident light 01 is coupled into the substrate 001 from the outside through the coupling-in grating 002.
  • Fig. 3 when three light beams of different wavelengths (such as RGB) are coupled into the substrate 001 at the same incident angle, the diffraction angles of the three different light beams are different.
  • Fig. 4 three light beams of the same wavelength are coupled into the substrate 001 through the coupling grating 002 at different incident angles, and different diffraction angles are also generated.
  • the propagation path lengths of light beams with different wavelengths or different incident angles after a total reflection in the substrate 001 of the same refractive index material will be different, which may cause two problems: first, due to pupil expansion, it is difficult to balance the intensity of light beams with different wavelengths at the same position of the coupling grating, resulting in the uneven color rainbow phenomenon observed by the human eye, as shown in Figure 5; second, due to the different diffraction angles of different light beams, some light beams with diffraction angles will be totally reflected when coupled into the substrate 001 and will enter the coupling grating 002 again, which may cause light leakage, which is called Backcoupling, and often occurs in the blue light beam B with a shorter wavelength, as shown in Figure 6.
  • the light-guiding device provided in the embodiment of the present application is a new diffraction light waveguide structure.
  • the waveguide substrate 1 By designing the waveguide substrate 1 to have at least two different refractive indices, a waveguide substrate 1 with a variable refractive index is formed.
  • the different refractive indices can modulate the light propagation path length of a part of the incident light beam 01 that is totally reflected once in the waveguide substrate 1, thereby solving the problem in the prior art that the incident light beam 01 is coupled into the waveguide substrate, resulting in differences in the light propagation path lengths due to different diffraction angles, which in turn causes a rainbow effect in the out-coupling area 3 and light leakage in the coupling-in area 2.
  • the waveguide substrate 1 has at least two different refractive indices.
  • the waveguide substrate 1 is, for example, a single-layer structure with a gradient refractive index, or can be a multi-layer structure composed of a plurality of materials with different refractive indices stacked together. This makes the waveguide substrate 1 in the embodiment of the present application a waveguide substrate with a gradient refractive index/a variable refractive index.
  • the waveguide substrate 1 is not limited to having only two different refractive indices, but may also have three or more different refractive indices, which is related to the situation of the incident light 01. Specifically, the more wavelengths of the light beams contained in the incident light 01 or the more incident angles, the more refractive indices the waveguide substrate 1 should have. It can also be understood that the waveguide substrate 1 can be made of materials with more different refractive indices.
  • the embodiment of the present application provides an optical waveguide design scheme.
  • a waveguide substrate 1 with different refractive indices it can be used to correct the light path length of a partial light beam coupled into the waveguide substrate 1 that undergoes total reflection propagation, so that each light beam coupled into the waveguide substrate 1 that undergoes total reflection propagation once can have the same or similar light propagation path length.
  • This can effectively avoid the rainbow effect in the decoupling area 3 and the light leakage (Backcoupling) in the coupling area 2, which is beneficial to improving the light efficiency and imaging quality.
  • a new waveguide substrate structure design method is used to achieve dispersion-free propagation of the incident light 01 in the waveguide substrate 1, thereby improving the overall optical efficiency of the light-guiding device and effectively solving the rainbow effect that is prone to occur in the outcoupling area 3.
  • the incident light 01 may, for example, include at least two light beams with the same wavelength incident on the coupling region 2 at different incident angles.
  • the incident light 01 may also be a multi-wavelength light beam including at least two light beams with different wavelengths, and the light beams with different wavelengths are incident on the coupling-in region 2 at the same incident angle.
  • the light guide device provided in the embodiment of the present application is not limited to the specific form of the incident light 01.
  • the incident light 01 can be multiple beams of single-wavelength light emitted by a single-wavelength light source, or can be multi-wavelength light emitted by a multi-wavelength light source, such as RGB light.
  • the waveguide substrate 1 can correspondingly modulate the light propagation paths of the first total reflections of different light beams in the incident light 01 based on the change of the refractive index, so that each light beam has the same or similar light propagation path length, thereby ensuring that the light output intensities of different light beams at the same position in the coupling-out zone 3 are relatively balanced after pupil expansion, so that the color observed by the human eye is relatively uniform; at the same time, it can avoid the leakage of light caused by the different diffraction angles of different light beams causing the light beams of some angles to be incident on the coupling-in zone 2 again through total reflection when coupled into the waveguide substrate 1, that is, the coupling efficiency can be improved to avoid the waste of light energy.
  • the coupling region 2 is located on the waveguide substrate 1 in a high refractive index region with the highest refractive index, and a gradient distribution of decreasing refractive index is formed on the waveguide substrate 1 from the coupling region 2 to a direction away from the coupling region 2 .
  • the coupling-in region 2 is designed to be located in the region with the highest refractive index on the waveguide substrate 1, and the refractive index gradually decreases as it moves away from the coupling-in region 2.
  • This design can modulate a light beam with a shorter wavelength (such as a blue light beam B) in the incident light 01, which can not only avoid the light leakage in the coupling-in area 2 as much as possible to improve the coupling-in efficiency, but also facilitates different light beams propagating to the coupling-out area 3 to have the same or similar propagation paths during a total reflection, so that the light beams of different colors coupled out from the coupling-out area 3 are evenly distributed, so that the human eye can see a picture with uniform color.
  • a shorter wavelength such as a blue light beam B
  • the waveguide substrate 1 is a single-layer structure with a gradient refractive index.
  • one form of the waveguide substrate 1 is an integral structure with different refractive indices.
  • the waveguide substrate 1 is a single-layer film or sheet structure with a set thickness and a gradually decreasing or increasing refractive index along a set direction.
  • the variation trend of the refractive index is related to the position of the coupling region 2 on the waveguide substrate 1. That is, the coupling region 2 is designed to be located in the region with the highest refractive index, and the farther away from the coupling region 2, the smaller the refractive index.
  • the refractive index presents a gradually decreasing gradient distribution from the coupling region 2 to the direction away from the coupling region 2 in the thickness direction of the waveguide substrate 1.
  • the coupling-in zone 2 when the waveguide substrate 1 has two different refractive indices, and the coupling-in zone 2 is located on one surface of the waveguide substrate 1, the refractive index of the surface where the coupling-in zone 2 is located should be the higher of the two refractive indices, and the other surface of the waveguide substrate 1 should be the lower of the two refractive indices.
  • the coupling-out zone 3 can be located on the same surface as the coupling-in zone 2, and both are in the high refractive index region.
  • the coupling-out zone 3 can also be located on the opposite side of the waveguide substrate 1, i.e., on a different surface from the coupling-in zone 2. In this case, the coupling-in zone 2 is located in the high refractive index region of the two refractive indices, and the coupling-out zone 3 is located in the low refractive index region of the two refractive indices.
  • the waveguide substrate 1 is not limited to having only two different refractive indices, and more materials with different refractive indices may be introduced to manufacture the waveguide substrate 1, so that the waveguide substrate 1 includes three or more refractive indices.
  • the gradient of the refractive index change becomes greater, so that the light propagation path length of light beams of different wavelengths and FOVs that are totally reflected once in the waveguide substrate 1 can be more accurately controlled, thereby better overcoming the defects in the prior art.
  • the waveguide substrate 1 is a single layer
  • the waveguide substrate 1 has a gradient refractive index, by controlling the gradient change of the refractive index, it can be achieved that light beams of different wavelengths, such as the red light beam R, the green light beam G and the blue light beam B (the three constitute the incident light beam 01 ), have the same or similar light propagation path length after a single total reflection propagation in the waveguide substrate 1 .
  • the refractive index should be designed to be a gradually decreasing gradient distribution in the direction away from the coupling-in region 2, but the difference between any two adjacent refractive indices may be the same or different, which is not limited in the embodiments of the present application.
  • the waveguide substrate 1 is a stacked structure of two or more layers made of materials with different refractive indices, wherein each material can form at least one layer on the waveguide substrate 1 and make the waveguide substrate 1 have a refractive index, so that the waveguide substrate 1 forms a gradient distribution of refractive index that changes gradually layer by layer.
  • the waveguide substrate 1 of the light-guiding device may also have another form, such as a multi-layer stacked structure.
  • the refractive index of each layer of the waveguide substrate 1 may be different, which may form a refractive index gradient distribution in which the refractive index changes layer by layer.
  • the coupling-in region 2 is, for example, disposed on a material layer with the highest refractive index, and similarly, the further away from the coupling-in region 2, the lower the refractive index. That is, the layer with the highest refractive index on the waveguide substrate 1, which is close to the coupling-in region 2 where external light is incident, becomes lower as it is further away from the coupling-in region 2.
  • the waveguide substrate 1 is not limited to the double-layer structure shown in FIG7 , and the waveguide substrate 1 may also be a composite structure of three or more layers, so that, for example, more changes in the refractive index are formed in thickness. On this basis, the more layers the waveguide substrate 1 includes, the more gradients of the refractive index change.
  • the refractive index gradient of the waveguide substrate 1 can be designed according to the incident light 01, and this is not limited in the embodiments of the present application. However, it should be noted that the thickness of the waveguide substrate 1 should not be too thick, otherwise it will affect the thinness of the entire light guide device, which will affect the user's wearing experience.
  • the waveguide substrate 1 is a double-layer structure formed of two materials with different refractive indices, one of which is a high refractive index layer 11, and the other is a low refractive index layer 12.
  • the coupling-in region 2 is, for example, disposed on the high refractive index layer 11, and the coupling-out region 3 can be disposed on the high refractive index layer 11.
  • the high refractive index layer 11 may also be located on the low refractive index layer 12, and there is no limitation on this.
  • the waveguide substrate 1 is a three-layer structure formed by three materials with different refractive indices, specifically including a high refractive index layer, a low refractive index layer, and a material layer between the two layers having a refractive index between the two layers. This also forms a gradient distribution of refractive indexes that changes step by step.
  • the coupling-in region 2 is located in the high refractive index layer, and the coupling-out region 3 can be located on the same surface as the coupling-in region 2, or on the opposite side of the coupling-in region 2.
  • the refractive index should be designed to be a gradually decreasing gradient distribution in the direction away from the coupling-in region 2, but the refractive index difference between any two adjacent layers can be the same or different, and this is not limited in the embodiments of the present application.
  • the coupling-in region 2 is located on at least one surface of the waveguide substrate 1 .
  • the coupling-in region 2 when the coupling-in region 2 is disposed on one surface of the waveguide substrate 1, a gradient distribution is formed on the waveguide substrate 1 along its thickness direction, with the refractive index gradually decreasing from the surface where the coupling-in region 2 is disposed to the other surface opposite thereto.
  • a gradient distribution of refractive index gradually decreasing from the surfaces on both sides to the middle region is formed on the waveguide substrate 1 along its thickness direction.
  • the change of the refractive index on the waveguide substrate 1 can be along the thickness direction of the waveguide substrate 1. More specifically, the refractive index presents a gradient distribution that gradually decreases from the position of the coupling-in region 2 to the direction away from the coupling-in region 2. That is, the waveguide substrate 1 presents a gradual change in the refractive index in the thickness direction.
  • the manufacturing process of such a waveguide substrate 1 is simpler and is conducive to mass production.
  • the coupling region 2 is not limited to being disposed on only one surface, that is, the coupling region 2 can also be disposed on two surfaces of the waveguide substrate 1.
  • each of the coupling regions 2 is located in the high refractive index region, and the waveguide substrate 1 forms a gradient distribution with a gradually decreasing refractive index from the two surfaces to the middle region along the thickness direction. From the perspective of the thickness direction of the waveguide substrate 1 as a whole, the refractive index of the middle region is the smallest.
  • the single-layer waveguide substrate 1 has a minimum refractive index in the central region.
  • the refractive index of the intermediate material layer is the smallest. In this way, a gradient change trend of gradually decreasing and then gradually increasing is formed in the thickness direction of the waveguide substrate 1.
  • the coupling-in region 2 is not located on the surface of the waveguide substrate 1 , but is located on the side of the waveguide substrate 1 .
  • the coupling region 2 is located on the side of the waveguide substrate 1, and the side is an inclined surface or a plane, and a gradient distribution of decreasing refractive index is formed on the waveguide substrate 1 from the coupling region 2 to the direction away from the coupling region 2; wherein, when the side is a plane, a coupling prism is arranged on one side of the coupling region 2.
  • the coupling-in area 2 When the coupling-in area 2 is located on the side of the waveguide substrate 1, the light leakage phenomenon of the coupling-in area 2 can be solved. In addition, the gradual change of the refractive index of the waveguide substrate 1 can better improve the coupling efficiency, so as to completely avoid the light leakage phenomenon in the coupling-in area and solve the rainbow effect of the decoupling area 3.
  • the incident light 01 includes at least a first light beam 011 and a second light beam 012.
  • the first light beam 011 can penetrate the interface and enter the low refractive index area, and after being reflected and modulated by the low refractive index area, it propagates to the interface and transmits into the high refractive index area, so that the light propagation path length of the first light beam 011 after a total reflection in the waveguide substrate 1 is the same as or close to the light propagation path length of the second light beam 012 after a total reflection in the waveguide substrate 1.
  • n1 and n2 are the refractive indices of the two dielectric materials
  • ⁇ 1 and ⁇ 2 are the angles between the light and the normal of the interface in the two dielectric materials.
  • the red light beam R and the blue light beam B with the largest difference in diffraction angle see FIG7 , in which the red light beam R is the second light beam 012 and the blue light beam B is the first light beam 011.
  • the red light beam R is the second light beam 012 and the blue light beam B is the first light beam 011.
  • the diffraction angle of the red light beam R is larger than that of the blue light beam B, according to Snell's law, it still follows the law of total reflection, which is the same as the single-layer waveguide.
  • the optical behavior of the blue light beam B is basically the same as that of the single-layer waveguide substrate.
  • the diffraction angle of the blue light beam B is smaller, so it can enter the low refractive index layer 12 through the interface.
  • the light angle is consistent with that after total reflection of the single-layer waveguide substrate, but the length of its propagation path is longer and closer to the propagation path length of the red light beam R, which can effectively reduce the rainbow effect of the outcoupling zone 3 and avoid the backcoupling phenomenon of the incoupling zone 2.
  • the coupling-in region 2 and the coupling-out region 3 are provided with a single diffractive optical element or a diffractive optical component composed of a plurality of diffractive optical elements.
  • the coupling region 2 is provided with a one-dimensional grating.
  • the one-dimensional grating is more suitable for application in the coupling part of most diffraction optical waveguides.
  • the direction of the one-dimensional grating vector is perpendicular to the grating line, which is the direction of its periodic change, and its length is equal to the inverse of the grating period.
  • the outcoupling region 3 is provided with a two-dimensional grating, a combination of a one-dimensional grating and a two-dimensional grating, a combination of one-dimensional gratings, etc.
  • a pupil expansion effect can be achieved in the outcoupling region 3 .
  • the coupling-in region 2 and the coupling-out region 3 are provided with diffractive optical elements, and the diffractive optical elements include one or more of a surface relief grating, a volume holographic grating, a liquid crystal grating and a photonic crystal.
  • the various gratings mentioned above are all diffraction gratings, and a suitable type of diffraction grating can be selected as needed and applied to the coupling-in region 2 of the light guide device, and no specific limitation is made in the embodiments of the present application. In other words, the solution of the present application does not limit the specific type of the coupling-in region 2, and has a wide range of applications.
  • the coupling-in region 2 and the coupling-out region 3 are located on the same side of the waveguide substrate 1 ; or, the coupling-in region 2 and the coupling-out region 3 are located on different sides of the waveguide substrate 1 .
  • an embodiment of the present application provides a wearable device.
  • the wearable device includes the light guide device and the optical engine as described above, wherein the optical engine is used to inject the incident light 01 or the image into the coupling-in area 2 on the light guide device.
  • the wearable device also includes a shell, and the light guide device and the optical machine are arranged in the shell.
  • the wearable device is, for example, a head-mounted display device such as an AR head-mounted display device.
  • the AR head mounted display device includes AR smart glasses or AR smart helmets, etc., which is not limited in this application.
  • the specific implementation of the wearable device of the embodiment of the present application can refer to the embodiment of the light guide device mentioned above, so it at least has all the beneficial effects brought by the technical solution of the above embodiment, which will not be repeated here one by one.

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Abstract

本申请实施例公开了一种导光器件以及可穿戴设备；其中，所述导光器件包括波导基底以及设于所述波导基底的耦入区和耦出区；其中，所述波导基底包括至少两种不同的折射率；所述耦入区用于将入射光线耦入所述波导基底内；所述波导基底用于将所述入射光线全反射传播至所述耦出区，且所述入射光线中的不同光束在所述波导基底内经不同折射率反射调制后能够具有相同或者相接近的光线传播路径长度；所述耦出区用于耦出传播至所述耦出区的光束。本申请实施例的导光器件，通过设计折射率变化的波导基底，可以矫正部分光束在波导基底内一次全反射传播的路径长度，避免在耦出区出现彩虹效应和在耦入区出现漏光(Backcoupling)现象，能提升光效。

Description

一种导光器件以及可穿戴设备
本申请要求于2022年11月2日提交中国专利局、申请号为202211362772.0、发明名称为“一种导光器件以及可穿戴设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及近眼显示技术领域，更具体地，本申请涉及一种导光器件以及可穿戴设备。
背景技术
衍射光波导是增强现实(AR)设备的核心。对于现有的衍射光波导方案来说，通常采用单一折射率的波导基底设计方案，而这种方案在实际应用中具有较多的缺陷问题如因耦出区的彩虹效应及耦入区的Backcoupling带来的光效降低，这将会影响到增强现实(AR)设备的画面显示性能，从而影响用户视觉体验感和沉浸体验感。特别是，耦出区的彩虹效应是目前衍射光波导方案设计非常明显的弊端，但就目前的技术而言，只能通过对波导基底上的光栅结构的新设计/改进尽可能的减弱该影响，然而效果却并不理想。
发明内容
本申请的目的在于提供的一种导光器件以及可穿戴设备的新技术方案。
第一方面，本申请实施例提供了一种导光器件。所述导光器件包括波导基底以及设于所述波导基底的耦入区和耦出区；
其中，所述波导基底包括至少两种不同的折射率；
所述耦入区用于将入射光线耦入所述波导基底内；
所述波导基底用于将所述入射光线全反射传播至所述耦出区，且所述入射光线中的不同光束在所述波导基底内经不同折射率反射调制后能够具有相同或者相接近的光线传播路径长度；
所述耦出区用于耦出传播至所述耦出区的光束。
可选地，所述耦入区在所述波导基底上位于折射率最高的高折射率 区域，所述波导基底上自所述耦入区到远离所述耦入区的方向形成折射率减小的梯度分布。
可选地，所述波导基底为折射率渐变的单层结构。
可选地，所述波导基底为采用不同折射率的材料制成两层或者两层以上的层叠结构，其中，每种材料在所述波导基底上可至少形成一层并使所述波导基底具有一种折射率，使得所述波导基底形成折射率逐层渐变的梯度分布。
可选地，所述耦入区位于所述波导基底的至少一个表面上。
可选地，当所述耦入区设于所述波导基底的一个表面上时，所述波导基底上沿其厚度方向形成自设置所述耦入区的表面向与之相对的另一个表面的折射率逐渐变小的梯度分布。
可选地，当所述耦入区分设在所述波导基底的两个表面上时，所述波导基底上沿其厚度方向形成由两侧的表面向中部区域的折射率逐渐变小的梯度分布。
可选地，所述耦入区位于所述波导基底的侧面，所述侧面为斜面或者平面，所述波导基底上自所述耦入区到远离所述耦入区的方向形成折射率减小的梯度分布；
当所述侧面为平面时，在所述耦入区的一侧设置有耦入棱镜。
可选地，所述入射光线至少包括第一光束和第二光束，在所述波导基底的高折射率与低折射率的界面上，当所述第二光束的衍射角度大于所述第一光束的衍射角度时，所述第一光束能够透过所述界面射入所述低折射率的区域，并经所述低折射率的区域反射调制后再传播至所述界面并透射进入所述高折射率的区域，使所述第一光束在所述波导基底内一次全反射的光线传播路径长度与所述第二光束在所述波导基底内一次全反射的光线传播路径长度相同或者相接近。
可选地，所述耦入区及所述耦出区设有单个衍射光学元件或者多个衍射光学元件组合成的衍射光学组件。
可选地，所述耦入区及所述耦出区设有衍射光学元件，所述衍射光学元件包括表面浮雕光栅、体全息光栅、液晶光栅及光子晶体中的一种或多 种。
可选地，所述耦入区与所述耦出区位于所述波导基底的同一侧；或者，
所述耦入区与所述耦出区分设在所述波导基底的异侧。
可选地，所述入射光线包括以不同入射角度射入所述耦入区的至少两束相同波长的光束；
或者，
所述入射光线为包含至少两束不同波长光束的多波长光线，且各不同波长的光束均以同一入射角度射入所述耦入区。
第二方面，本申请实施例提供了一种可穿戴设备。所述可穿戴设备包括：
如第一方面所述的导光器件；以及
光机，所述光机用以将所述入射的光线或者图像射入所述导光器件上的所述耦入区中。
本申请的有益效果在于：
本申请实施例提供了一种光波导设计方案，通过设计包括不同折射率的波导基底，可用以矫正耦入至波导基底内部分光束发生全反射传播的光线路径长度，使得耦入波导基底内一次全反射传播的各光束可以具有相同或相接近的光线传播路径长度，如此能够有效避免出现在耦出区产生彩虹效应及在耦入区产生漏光(Backcoupling)等现象，这利于提升光效和成像质量。
通过以下参照附图对本申请的示例性实施例的详细描述，本申请的其它特征及其优点将会变得清楚。
附图说明
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一部分附图，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据提供的附图获得其他的附图。
图1是本申请实施例的导光器件的结构示意图之一；
图2是本申请实施例的导光器件的结构示意图之二；
图3是现有的衍射光波导的光线传播路径示意图之一；
图4是现有的衍射光波导的光线传播路径示意图之二；
图5是现有的衍射光波导的光线传播路径示意图之三；
图6是现有的衍射光波导的光线传播路径示意图之四；
图7是本申请实施例的导光器件的光线传播路径示意图之一；
图8是本申请实施例的导光器件的光线传播路径示意图之二。
附图标记说明：
1、波导基底；11、高折射率层；12、低折射率层；2、耦入区；3、耦出
区；01、入射光线；
011、第一光束；012、第二光束；
001、基底；002、耦入光栅。
具体实施方式
现在将参照附图来详细描述本申请的各种示例性实施例。应注意到：除非另外具体说明，否则在这些实施例中阐述的部件和步骤的相对布置、数字表达式和数值不限制本申请的范围。
以下对至少一个示例性实施例的描述实际上仅仅是说明性的，决不作为对本申请及其应用或使用的任何限制。
对于相关领域普通技术人员已知的技术、方法和设备可能不作详细讨论，但在适当情况下，所述技术、方法和设备应当被视为说明书的一部分。
在这里示出和讨论的所有例子中，任何具体值应被解释为仅仅是示例性的，而不是作为限制。因此，示例性实施例的其它例子可以具有不同的值。
应注意到：相似的标号和字母在下面的附图中表示类似项，因此，一旦某一项在一个附图中被定义，则在随后的附图中不需要对其进行进一步讨论。
下面结合附图对本申请实施例提供的导光器件以及可穿戴设备进行详细地描述。
在多种形式的可穿戴设备中，以AR头戴显示设备为例，AR头戴显示设备通常包括微型显示屏和光学模组。AR头戴显示设备的光学模组中常用的光学元件例如有棱镜、自由曲面镜片及光波导器件等。在上述的这些光学元件中，光波导器件包括几何光波导和衍射光波导。由于衍射光波导具有良好的光学性能，使其在AR设备中得到了较为广泛的应用。
根据本申请的一个实施例，提供了一种导光器件，该导光器件例如为光波导器件，所述光波导器件例如为衍射光波导。
本申请实施例提供的导光器件例如可应用于例如头戴显示设备中，如AR智能眼镜、AR头盔等，可以使用户获得沉浸感较佳的视觉体验感。
本申请实施例提供的导光器件，参见图1和图2，以及图7和图8，所述导光器件包括波导基底1以及设于所述波导基底1的耦入区2和耦出区3；其中，所述波导基底1包括至少两种不同的折射率；所述耦入区2用于将入射光线01耦入所述波导基底1内；所述波导基底1用于将所述入射光线01全反射传播至所述耦出区3，且所述入射光线01中的不同光束在所述波导基底1内经不同折射率反射调制后能够具有相同或者相接近的光线传播路径长度；所述耦出区3用于耦出传播至所述耦出区3的光束。
传统的衍射光波导，其基底通常采用同一折射率的材料制成，基于其上的耦入光栅的色散效应，入射光线中不同的光束在经耦入光栅进入基底中之后会具有不同的传输通道，也即不同的光束会以不同的全反射角度在基底内全反射传播至耦出光栅，这会导致不同的光束在基底内一次全反射传播时的光线传播路径长度存在明显差异，会在耦出光栅耦出光线时在人眼中引起彩虹效应，另外光束还可能会在耦入光栅处产生漏光现象(Backcoupling)，而这些现象都会带来光效降低、影响成像质量，进而影响用户的观看体验感。
具体而言，参见图3至图6，光源可以发射出入射光线01，入射光线01例如为RGB三色光，即该入射光线01中例如包含有红光光束R、蓝光光束B及绿光光束G，其中，蓝光光束B的波长最短，红光光束R的波长最长。对于现有的单一折射率的基底001而言，因为其上的耦入光栅002的衍射效应，入射光线01在从外界经耦入光栅002耦入基底001 时不同波长和/或不同入射角度的光束所产生的衍射角度会有所不同。
例如，参见图3，三种不同波长的光束(如RGB)当以同一入射角度耦入至基底001内，三束不同的光束的衍射角度各不相同。另外，还有一种形式，参见图4，三束相同波长的光束以不同的入射角度经耦入光栅002耦入至基底001内，同样也会产生衍射角度不同的情况。
而不同波长或者不同入射角度的光束在同一折射率材料的基底001中一次全反射的光线传播路径长度会不同，这样可能会带来两方面的问题：第一方面因扩瞳导致在耦出光栅的同一位置不同波长出光的强度很难平衡，从而导致人眼观察到的色彩不均匀的彩虹现象，可参见图5；第二方面，因不同光束的衍射角度不同会使得部分衍射角度的光束在耦入基底001时经全反射再次入射耦入光栅002，这可能会造成光的泄露，称之为Backcoupling，尤其经常出现在波长较短的蓝光光束B上，参见图6。
本申请实施例提供的导光器件，其为一种新的衍射光波导结构，通过将所述波导基底1设计为至少具有两种不同的折射率，形成了一种折射率变化的波导基底1，不同的折射率能够调制入射光线01中部分光束在该波导基底1内一次全反射的光线传播路径长度，从而解决了现有技术中存在的入射光线01耦入波导基底内因衍射角度各有不同而导致的光线传播路径长度存在差异，进而引起的耦出区3的彩虹效应及耦入区2的漏光现象。
本申请实施例提供的导光器件，其中的所述波导基底1具有至少两种不同的折射率。可选的是，所述波导基底1例如为一个折射率渐变的单层结构，当然也可以为由多种不同折射率的材料经层叠组合的多层结构。使得本申请实施例的波导基底1为一种渐变折射率/折射率变化的波导基底。
需要说明的是，在本申请的实施例中，所述波导基底1并不限于仅具有两种不同的折射率，还可以具有三种或者三种以上的不同折射率，这与入射光线01的情况相关。具体而言，所述入射光线01包含光束的波长越多或者入射角度越多，所述波导基底1应当采用更多种的折射率。也可以理解为所述波导基底1可以采用更多不同折射率的材料制作。
本申请实施例提供了一种光波导设计方案，通过设计包括不同折射率的波导基底1，可用以矫正耦入至波导基底1内部分光束发生全反射传播的光线路径长度，使得耦入波导基底1内一次全反射传播的各光束可以具有相同或相接近的光线传播路径长度，如此能够有效避免出现在耦出区3产生彩虹效应及在耦入区2产生漏光(Backcoupling)等现象，这利于提升光效和成像质量。
也就是说，在本申请的实施例中，通过一种新的波导基底结构设计方式实现了入射光线01在所述波导基底1中的无色散传播，提升了导光器件的整体光学效率，同时很好的解决了耦出区3处容易出现的彩虹效应。
其中，所述入射光线01例如可以包括以不同入射角度射入所述耦入区2的至少两束相同波长的光束。
可选的是，所述入射光线01还可以为包含至少两束不同波长光束的多波长光线，且不同波长的光束均以同一入射角度射入所述耦入区2。
本申请实施例提供的导光器件，其对于入射光线01的具体形式可以不作限制。所述入射光线01可以是单波长光源发出的多束单波长光线，也可以是多波长光源发射出的多波长光线例如RGB光等。
本申请实施例提供的导光器件，上述任一种形式的所述入射光线01在经所述耦入区2耦入至所述波导基底1后，所述波导基底1基于折射率的变化可以对所述入射光线01中不同光束的一次全反射的光线传播路径进行相应的调制，使各光束具有相同或相接近的光线传播路径长度，这样能保证扩瞳后在所述耦出区3的同一位置不同光束的出光强度较平衡，使得人眼所观察到的色彩较为均匀；同时，可以避免因不同光束的衍射角度不同会使得部分角度的光束在耦入所述波导基底1时会经全反射再次入射至所述耦入区2而造成光的泄露，也即可以提高耦入效率，避免光能浪费。
在本申请的一些示例中，参见图7及图8，所述耦入区2在所述波导基底1上位于折射率最高的高折射率区域，所述波导基底1上自所述耦入区2到远离所述耦入区2的方向形成折射率减小的梯度分布。
在本申请实施例的导光器件中，所述耦入区2设计位于所述波导基底1上折射率最高区域，越远离所述耦入区2折射率会呈现逐渐变小的趋 势。该设计例如可以调制入射光线01中如波长较短的光束(例如蓝光光束B)，不仅可以尽量避免光束在所述耦入区2产生漏光的现象，以提高耦入效率，而且这样的设计方式也利于传播至所述耦出区3的不同光束在一次全反射的过程中能够具有相同或者相接近的传播路径，从而使得从所述耦出区3耦出的例如不同颜色的光束分布均匀，使人眼可以看到均匀色彩的画面。
在本申请的一个例子中，所述波导基底1为折射率渐变的单层结构。
也就是说，所述波导基底1的一种形式为具有不同折射率的一个整体结构。例如，所述波导基底1为具有设定厚度、且其上按照设定方向呈现折射率逐渐减小或者逐渐增大的单层薄膜或者片状结构。
在上述例子中，参见图8，所述折射率的变化趋势与所述波导基底1上设置所述耦入区2的位置相关。也就是说，所述耦入区2设计位于折射率最高的区域，而越远离所述耦入区2则折射率越小。
可以理解的是，基于上述例子中的波导基底1，当所述耦入区2设于所述波导基底1的一个表面上时，在所述波导基底1的厚度方向上自所述耦入区2至远离所述耦入区2的方向，折射率呈现逐渐变小的梯度分布。
进一步地，当所述波导基底1具有两种不同折射率，且所述耦入区2位于所述波导基底1的一个表面上时，所述耦入区2所在表面的折射率应当是两种折射率中高的，所述波导基底1的另一表面应当为两种折射率中低的。在此基础上，可选的是，所述耦出区3可以与所述耦入区2位于同一表面，则二者均在高折射率区。当然，所述耦出区3也可以与所述耦入区2位于所述波导基底1的异侧即不同表面，此时，所述耦入区2位于两种折射率中的高折射率区，所述耦出区3位于两种折射率中低折射率区。
需要说明的是，所述波导基底1不限于仅具有两种不同的折射率，还可以引入更多的不同折射率的材料制作所述波导基底1，以使所述波导基底1包括三种或者更多的折射率。
在所述波导基底1中，随着所添加的材料越多，折射率变化的梯度越多，如此越可以精确的控制不同波长与FOV的光束在波导基底1内一次全反射的光线传播路径长度，从而更好的克服现有技术中的缺陷。
例如，参见图8，虽然所述波导基底1为单层，但是当所述波导基底1存在渐变折射率时，通过控制折射率的梯度变化，可以实现不同波长的光束如红光光束R、绿光光束G及蓝光光束B(三者组成入射光线01)在波导基底1内一次全反射传播具有相同或者相接近的光线传播路径长度。
当所述波导基底1包括三种或者三种以上的折射率时，沿远离所述耦入区2的方向折射率应当设计为逐渐减小的梯度分布，但任意相邻的两个折射率之间的差值可以相同也可以不同，本申请实施例中对此不做限制。
在本申请的另一个例子中，参见图7，所述波导基底1为采用不同折射率的材料制成两层或者两层以上的层叠结构，其中，每种材料在所述波导基底1上可至少形成一层并使所述波导基底1具有一种折射率，使得所述波导基底1形成折射率逐层渐变的梯度分布。
参见图7，所述导光器件的波导基底1还可以具有另一种形式，如为一种多层叠合结构。在此基础上，所述波导基底1的每一层的折射率可以不同，这可以形成一种折射率逐层变化的折射率梯度分布。所述耦入区2例如被设置在折射率最高的一层材料层上，同样的，越远离所述耦入区2折射率逐渐减小。也即，在所述波导基底1上折射率最高一层靠近外界光入射的耦入区2，越远离所述耦入区2折射率越低。
所述波导基底1不限于为图7示出的双层结构，所述波导基底1还可以为三层或三层以上的复合结构，这样例如在厚度形成折射率的更多变化。在此基础上，所述波导基底1包含的层数越多，折射率变化的梯度就越多。
具体而言，可以根据入射光线01的情况设计所述波导基底1的折射率变化梯度，本申请实施例中对此不做限制。但应当注意的是，所述波导基底1的厚度不易过厚，否则会影响到整个导光器件的轻薄化，这会影响用户的佩戴体验感。
例如，参见图7，所述波导基底1为采用两种不同折射率的材料形成的双层结构，其中一层为高折射率层11，而另一层为低折射率层12。所述耦入区2例如设置在高折射率层11上，而所述耦出区3既可以位于所 述高折射率层11上，也可以位于所述低折射率层12上，对此不做限制。
又例如，所述波导基底1为采用三种不同折射率的材料形成的三层结构，具体包括一层为高折射率层，另一层为低折射率层，而介于该两层之间的材料层的折射率也介于该两层的折射率之间。这也形成了折射率逐级变化的梯度分布。此时，所述耦入区2位于高折射率层，所述耦出区3可与所述耦入区2位于同一表面，也可以与所述耦入区2位于异侧。
需要说明的是，当所述波导基底1为三层或者三层以上时，沿远离所述耦入区2的方向折射率应设计为逐渐减小的梯度分布，但任意相邻的两层之间的折射率差值可以相同也可以不同，本申请实施例中对此不做限制。
在本申请的一些示例中，参见图7及图8所述耦入区2位于所述波导基底1的至少一个表面上。
可选的是，当所述耦入区2设于所述波导基底1的一个表面上时，所述波导基底1上沿其厚度方向形成自设置所述耦入区2的表面向与之相对的另一个表面的折射率逐渐变小的梯度分布。
可选的是，当所述耦入区2分设在所述波导基底1的两个表面上时，所述波导基底1上沿其厚度方向形成由两侧的表面向中部区域的折射率逐渐变小的梯度分布。
也就是说，当在所述波导基底1的表面上布设耦入区2时，所述波导基底1上折射率的变化可以是沿所述波导基底1的厚度方向。更具体的为自所述耦入区2的位置开始向远离所述耦入区2的方向折射率呈现出逐渐变小的梯度分布。也即所述波导基底1在厚度方向呈现折射率渐变。这种波导基底1的制作工艺更加简单，利于大批量生产。
在另一些波导基底1上，耦入区2并不限于仅设于一个表面上，也即耦入区2还可以分设在所述波导基底1的两个表面上。在此基础上，各所述耦入区2均位于所述高折射率区域，则所述波导基底1沿厚度方向上由两个表面分别向中部区域形成折射率逐渐变小的梯度分布。而从所述波导基底1的厚度方向整体来看，中部区域的折射率是最小的。
具体地，所述单层的波导基底1，其中部区域折射率最小。所述多层 的波导基底1，其中间材料层的折射率最小。这样，在所述波导基底1的厚度方向形成逐渐变小再逐渐增大的梯度变化趋势。
此外，可选的是，在一些导光器件上，所述耦入区2并不位于所述波导基底1的表面上，而是位于所述波导基底1的侧面。
在本申请的一些示例中，所述耦入区2位于所述波导基底1的侧面，所述侧面为斜面或者平面，所述波导基底1上自所述耦入区2到远离所述耦入区2的方向形成折射率减小的梯度分布；其中，当所述侧面为平面时，在所述耦入区2的一侧设置有耦入棱镜。
当所述耦入区2位于所述波导基底1的侧面时，所述耦入区2的漏光现象可以得以解决，加上所述波导基底1的折射率渐变可以更好的提升耦入效率，用以完全避免耦入区漏光现象，同时解决了耦出区3的彩虹效应。
本申请实施例提供的导光器件中，所述入射光线01至少包括第一光束011和第二光束012，在所述波导基底1的高折射率与低折射率的界面上，当所述第二光束012的衍射角度大于所述第一光束011的衍射角度时，所述第一光束011能够透过所述界面射入所述低折射率的区域，并经所述低折射率的区域反射调制后再传播至所述界面并透射进入所述高折射率的区域，使所述第一光束011在所述波导基底1内一次全反射的光线传播路径长度与所述第二光束012在所述波导基底1内一次全反射的光线传播路径长度相同或者相接近。
基本的光学斯涅耳定律可知，在不同介质的交界面其光线的角度变化遵循下述公式：
n1*sin(θ1)＝n2*sin(θ2)；
其中，n1，n2分别是两个介质材料的折射率，θ1，θ2分别是两个介质材料中光线与界面的法线夹角。
例如，以衍射角度相差最大的红光光束R和蓝光光束B为例，参见图7，图7中红光光束R为第二光束012，蓝光光束B为第一光束011。在高折射率层11与低折射率层12的界面，因为红光光束R的衍射角度相比于蓝光光束B更大，根据斯涅耳定律其仍然遵循全反射定律，与单层波 导基底时的光学行为基本一致。而蓝光光束B的衍射角度更小，因此其可以透过界面进入所述低折射率层12。在所述低折射率层12中经过一段距离的传播入射至所述低折射率层12的底侧界面并发生全发射重新回到所述低折射率层12与所述高折射率层11的交界面并透射进入所述高折射率层11，其光线角度和单层波导基底全反射后一致，但是其传播路径的长度要更长，且更接近所述红光光束R的传播路径长度，这可以有效减弱耦出区3的彩虹效应和避免耦入区2的Backcoupling现象。
在本申请的一些示例中，所述耦入区2及所述耦出区3设有单个衍射光学元件或者多个衍射光学元件组合成的衍射光学组件。
例如，所述耦入区2设有一维光栅。一维光栅较为适合应用于大多数衍射光波导的耦入部分。一维光栅矢量的方向垂直于光栅线，是其周期性变化的方向，其长度等于光栅周期的倒数。
例如，所述耦出区3设有二维光栅、一维光栅与二维光栅的组合、一维光栅的组合等。在所述耦出区3可以实现扩瞳效果。
可选的是，所述耦入区2及所述耦出区3设有衍射光学元件，所述衍射光学元件包括表面浮雕光栅、体全息光栅、液晶光栅及光子晶体中的一种或多种。
上述的各种光栅均为衍射光栅，可以根据需要选择合适类型的衍射光栅应用在导光器件的耦入区2，本申请实施例中对此不做具体限制。也就是说，本申请的方案对于所述耦入区2的具体类型可以不做限定，适用范围较广。
在本申请的实施例中，所述耦入区2与所述耦出区3位于所述波导基底1的同一侧；或者，所述耦入区2与所述耦出区3分设在所述波导基底1的异侧。
另一方面，本申请实施例提供了一种可穿戴设备。所述可穿戴设备包括如上所述的导光器件及光机；其中，所述光机用以将所述入射光线01或者图像射入所述导光器件上的所述耦入区2中。
所述可穿戴设备还包括壳体，所述导光器件及光机设于所述壳体内。
所述可穿戴设备例如为头戴显示设备例如AR头戴显示设备。
所述AR头戴显示设备包括AR智能眼镜或者AR智能头盔等，本申请中对此不做限制。
本申请实施例的可穿戴设备的具体实施方式可以参照上述的导光器件的实施例，因此至少具有上述实施例的技术方案所带来的所有有益效果，在此不再一一赘述。
上文实施例中重点描述的是各个实施例之间的不同，各个实施例之间不同的优化特征只要不矛盾，均可以组合形成更优的实施例，考虑到行文简洁，在此则不再赘述。
虽然已经通过示例对本申请的一些特定实施例进行了详细说明，但是本领域的技术人员应该理解，以上示例仅是为了进行说明，而不是为了限制本申请的范围。本领域的技术人员应该理解，可在不脱离本申请的范围和精神的情况下，对以上实施例进行修改。本申请的范围由所附权利要求来限定。

Claims (14)

  1. 一种导光器件，其特征在于，所述导光器件包括波导基底(1)以及设于所述波导基底(1)的耦入区(2)和耦出区(3)；
    其中，所述波导基底(1)包括至少两种不同的折射率；
    所述耦入区(2)用于将入射光线(01)耦入所述波导基底(1)内；
    所述波导基底(1)用于将所述入射光线(01)全反射传播至所述耦出区(3)，且所述入射光线(01)中的不同光束在所述波导基底(1)内经不同折射率反射调制后能够具有相同或者相接近的光线传播路径长度；
    所述耦出区(3)用于耦出传播至所述耦出区(3)的光束。
  2. 根据权利要求1所述的导光器件，其特征在于，所述耦入区(2)在所述波导基底(1)上位于折射率最高的高折射率区域，所述波导基底(1)上自所述耦入区(2)到远离所述耦入区(2)的方向形成折射率减小的梯度分布。
  3. 根据权利要求1所述的导光器件，其特征在于，所述波导基底(1)为折射率渐变的单层结构。
  4. 根据权利要求1所述的导光器件，其特征在于，所述波导基底(1)为采用不同折射率的材料制成两层或者两层以上的层叠结构，其中，每种材料在所述波导基底(1)上可至少形成一层并使所述波导基底(1)具有一种折射率，使得所述波导基底(1)形成折射率逐层渐变的梯度分布。
  5. 根据权利要求1所述的导光器件，其特征在于，所述耦入区(2)位于所述波导基底(1)的至少一个表面上。
  6. 根据权利要求5所述的导光器件，其特征在于，当所述耦入区(2)设于所述波导基底(1)的一个表面上时，所述波导基底(1)上沿其厚度方向形成自设置所述耦入区(2)的表面向与之相对的另一个表面的折射率逐渐变小的梯度分布。
  7. 根据权利要求5所述的导光器件，其特征在于，当所述耦入区(2)分设在所述波导基底(1)的两个表面上时，所述波导基底(1)上沿其厚度方向形成由两侧的表面向中部区域的折射率逐渐变小的梯度分布。
  8. 根据权利要求1所述的导光器件，其特征在于，所述耦入区(2)位于所述波导基底(1)的侧面，所述侧面为斜面或者平面，所述波导基底(1)上自所述耦入区(2)到远离所述耦入区(2)的方向形成折射率减小的梯度分布；
    当所述侧面为平面时，在所述耦入区(2)的一侧设置有耦入棱镜。
  9. 根据权利要求1所述的导光器件，其特征在于，所述入射光线(01)至少包括第一光束(011)和第二光束(012)，在所述波导基底(1)的高折射率与低折射率的界面上，当所述第二光束(012)的衍射角度大于所述第一光束(011)的衍射角度时，所述第一光束(011)能够透过所述界面射入所述低折射率的区域，并经所述低折射率的区域反射调制后再传播至所述界面并透射进入所述高折射率的区域，使所述第一光束(011)在所述波导基底(1)内一次全反射的光线传播路径长度与所述第二光束(012)在所述波导基底(1)内一次全反射的光线传播路径长度相同或者相接近。
  10. 根据权利要求1所述的导光器件，其特征在于，所述耦入区(2)及所述耦出区(3)设有单个衍射光学元件或者多个衍射光学元件组合成的衍射光学组件。
  11. 根据权利要求1所述的导光器件，其特征在于，所述耦入区(2)及所述耦出区(3)设有衍射光学元件，所述衍射光学元件包括表面浮雕光栅、体全息光栅、液晶光栅及光子晶体中的一种或多种。
  12. 根据权利要求1所述的导光器件，其特征在于，所述耦入区(2)与所述耦出区(3)位于所述波导基底(1)的同一侧；或者，
    所述耦入区(2)与所述耦出区(3)分设在所述波导基底(1)的异侧。
  13. 根据权利要求1所述的导光器件，其特征在于，所述入射光线(01)包括以不同入射角度射入所述耦入区(2)的至少两束相同波长的光束；
    或者，
    所述入射光线(01)为包含至少两束不同波长光束的多波长光线，且各不同波长的光束均以同一入射角度射入所述耦入区(2)。
  14. 一种可穿戴设备，其特征在于，所述可穿戴设备包括：
    如权利要求1-13中任一项所述的导光器件；以及
    光机，所述光机用以将所述入射光线(01)或者图像射入所述导光器件上的耦入区(2)中。
PCT/CN2023/106502 2022-11-02 2023-07-10 一种导光器件以及可穿戴设备 WO2024093348A1 (zh)

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