WO2022242659A1 - 光导及近眼显示装置 - Google Patents

光导及近眼显示装置 Download PDF

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Publication number
WO2022242659A1
WO2022242659A1 PCT/CN2022/093392 CN2022093392W WO2022242659A1 WO 2022242659 A1 WO2022242659 A1 WO 2022242659A1 CN 2022093392 W CN2022093392 W CN 2022093392W WO 2022242659 A1 WO2022242659 A1 WO 2022242659A1
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Prior art keywords
light
grating
light guide
vector
area
Prior art date
Application number
PCT/CN2022/093392
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English (en)
French (fr)
Inventor
周海峰
刘力铭
丁子谦
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华为技术有限公司
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Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP22803979.8A priority Critical patent/EP4321909A4/en
Publication of WO2022242659A1 publication Critical patent/WO2022242659A1/zh
Priority to US18/508,930 priority patent/US20240077736A1/en

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    • 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
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0015—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0016—Grooves, prisms, gratings, scattering particles or rough surfaces
    • 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
    • G02B27/42—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect
    • G02B27/4205—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
    • 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
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
    • G02B6/0026—Wavelength selective element, sheet or layer, e.g. filter or grating
    • 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
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0036—2-D arrangement of prisms, protrusions, indentations or roughened surfaces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/017—Head mounted
    • G02B2027/0178—Eyeglass type

Definitions

  • the present application relates to the technical field of optical devices, in particular to a light guide and a near-eye display device.
  • the larger the FOV range the larger the range of the virtual image that the user can see. Therefore, in order to increase the FOV range while confining multiple colors of light within the light guide, it is currently more intuitive that the light guide includes multiple light guide plates, each of which transmits a small spectral range, but the disadvantage of this approach is Doubling the number of light guide plates in the light guide will increase the cost and weight of the light guide, and the assembly process is relatively complicated, which is not suitable for realizing the requirement of a near-eye display device with a minimalist appearance.
  • the present application provides a light guide and a near-eye display device to increase the viewing angle supported by the light guide and simplify the structure of the light guide.
  • the present application provides a light guide.
  • the light guide includes a light guide plate and a two-dimensional grating.
  • the two-dimensional grating is specifically arranged on the surface of the light guide plate, and can be integrally formed with the light guide plate.
  • the two-dimensional grating includes a plurality of grating units arranged in a planar shape, specifically, the grating units are arranged at a first distance along the first direction, and at a second distance along the second direction.
  • the above-mentioned first direction intersects with the second direction.
  • the above-mentioned two-dimensional grating includes a light-emitting area and a light-incoming area arranged along the third direction, and the fourth direction is perpendicular to the third direction.
  • the above-mentioned third direction is the y-axis direction of the Cartesian coordinate system
  • the fourth direction is the Cartesian coordinate system.
  • the above-mentioned first direction, second direction, third direction and fourth direction are located on the same plane and any two directions do not overlap. That is to say, the first direction and the second direction respectively form a certain angle with the coordinate axes of the rectangular coordinate system. The included angle is not 0° or 90°.
  • the above-mentioned grating unit is used to diffract one beam of incident light into at least three beams of outgoing light.
  • the grating unit in the light incident region of the light guide receives the light, and the above grating unit is used to diffract one beam of incident light into at least three beams of outgoing light.
  • the light is diffused by the grating unit in the light guide plate, and is emitted from the grating unit in the light exit area.
  • the grating unit diffracts one beam of incident light into at least three beams of outgoing light for transmission. Applications are not limited.
  • the light entering the light guide has multiple transmission paths, which can allow part of the field of view to escape from the light guide when it is transmitted through the main path, and then use the compensation path to compensate for the escaped field of view, so that a light guide plate can be used to support a larger Transmission of field of view. That is to say, the light guide in this solution can transmit a larger viewing angle, and the structure of the light guide is relatively simple.
  • the grating units arranged in the two-dimensional grating can generate a first grating vector, a second grating vector and multiple combined grating vectors.
  • the first grating vector is perpendicular to the first direction
  • the second grating vector is perpendicular to the second direction
  • the combined grating vector is the vector sum of the first grating vector of the diffraction order M1 and the second grating vector of the diffraction order M2;
  • the diffraction order M1 and the diffraction order M2 are integers, which can be positive integers, negative integers or zero, and the specific values are not limited in this application.
  • the grating unit in the light incident area receives light, and the light is emitted from the grating unit in the light exit area after being diffused by the grating unit in the light guide plate. After the light irradiates the grating unit, it is transmitted under the action of the first grating vector, the second grating vector and the combined grating vector, and the vector sum of the grating vectors received during the light transmission is zero.
  • the number of combined grating vectors of the grating unit is not limited, and there may be multiple combined grating vectors. Therefore, the first grating vector, the second grating vector, and the combined grating vector may form multiple optical transmission paths.
  • the light When the light hits the grating unit, it can be diffracted into at least three exiting rays formed under the influence of the first grating vector, the second grating vector and the resultant grating vector. Part of the field of view can be allowed to escape from the light guide when the main path is transmitted, and then the compensation path can be used to compensate the escaped field of view, so that a light guide plate can be used to support the transmission of a larger field of view. That is to say, the light guide in this solution can transmit a larger viewing angle, and the structure of the light guide is relatively simple.
  • the acute angle between the first direction and the fourth direction may be between 10° and 80°, and the acute angle between the second direction and the fourth direction may be between 10° and 80°.
  • the first direction and the second direction in which the grating units are arranged are symmetrical with respect to the third direction. That is to say, the first direction and the second direction face two sides of the third direction, and the included angle with the third direction is equal.
  • the arrangement of the grating units is relatively regular, and the directions of the first grating vector, the second grating vector and the combined grating vector are relatively symmetrical and regular, and it is relatively easy to make the vector sum of the guided grating vectors be zero during light transmission.
  • the above-mentioned diffraction order M1 can include -3, -2, -1, 0, 1, 2 and 3, and the diffraction order M2 can include -3, -2 , -1, 0, 1, 2, and 3.
  • the diffraction order in this scheme refers to the diffraction order in the wave vector space, and the diffraction order is relatively high, so that it is convenient to form a variety of combined grating vectors to obtain a compensation path that meets the compensation requirements.
  • Adopting the light guide in the technical solution of the present application can support the transmission of images with a viewing angle of at least 60°, so as to improve the viewing angle of a near-eye display device using the light guide and improve user experience.
  • the two-dimensional grating When specifically setting a two-dimensional grating, the two-dimensional grating includes at least two sub-regions.
  • the shapes of the grating units in adjacent sub-regions are different, while the shapes of the grating units in the same sub-region are the same. This solution can obtain different diffraction energy levels through reasonable design of the shape of the grating unit, so as to design a reasonable main path and compensation path.
  • the forms of the multiple grating units of the two-dimensional grating can also be the same. That is, all the grating units arranged on the surface of the light guide have the same shape, so as to simplify the preparation process of the light guide.
  • the two-dimensional grating is arranged on the surface of the light guide plate, and the two-dimensional grating can be located on the same side surface of the light guide plate.
  • a part of the area of the two-dimensional grating can be located on one side of the surface, and the rest of the area can be located on the other side of the surface.
  • the above-mentioned two-dimensional grating may further include at least two subregions, the first distances of adjacent subregions are different, and the second regions of adjacent subregions are different. That is to say, the grating periods of different sub-regions are different, so that different grating vectors can be formed to increase the grating vectors that can be selected.
  • the two-dimensional grating may include a first sub-region and a second sub-region.
  • the light incident area and the light exit area are located in the first sub-area, and the second sub-area is located on a side of the light exit area away from the light entrance area.
  • the first distance of the first sub-area is greater than the first distance of the second sub-area, and the second distance of the first sub-area is greater than the second distance of the second sub-area. That is to say, the grating period of the second sub-region is smaller than that of the first sub-region.
  • the above-mentioned first distance may be between 200 nm and 600 nm
  • the second distance may be specifically between 200 nm and 600 nm. Values of the above-mentioned first distance and the second distance may be set according to actual requirements, which are not limited in this application.
  • the present application also provides a near-eye display device.
  • the near-eye display device includes a casing, an optical machine, and the light guide in any of the above technical solutions.
  • the optical machine and the light guide are arranged in the housing, and the optical machine is used to generate light and send the generated light to the light incident area of the light guide.
  • the near-eye display device in this solution has a larger field of view and a relatively compact structure, which is conducive to miniaturization.
  • the specific type of the near-eye display device is not limited, and may be virtual reality glasses or augmented reality glasses. As long as a near-eye display device that needs to use light guides to transmit images falls within the protection scope of the present application.
  • the optical machine may include a laser, a scanner and a controller.
  • the scanner of the optical machine is used to scan the incident light emitted by the laser and send it to the light incident area of the light guide.
  • optical machine may be a liquid crystal on silicon optical machine or a digital light processing optical machine.
  • the light generated by the above light machine includes red light, green light and blue light.
  • the light guide in this solution can realize the transmission of three-color pictures with a large field of view, and the structure is relatively simple.
  • Fig. 1 is a schematic diagram of a front view structure of the light guide in the embodiment of the present application
  • Fig. 2 is a schematic diagram of a lateral structure of the light guide in the embodiment of the present application.
  • FIG. 3 is a schematic diagram of another lateral structure of the light guide in the embodiment of the present application.
  • Fig. 4 is a schematic diagram of the wave vector space structure of the light guide in the prior art
  • FIG. 5 is a schematic diagram of the local distribution of grating units in the embodiment of the present application.
  • Fig. 6 is a schematic structural diagram of light guide to picture transmission in the embodiment of the present application.
  • Fig. 7 is a schematic diagram of the red light transmission path of the light guide to the picture in the embodiment of the present application.
  • Fig. 8 is a schematic diagram of the propagation path of red light with an incident angle of zero degrees in the light guide in the embodiment of the present application;
  • FIG. 9 is a schematic diagram of the compensation path of the Blu-ray field of view in the transmission screen of the embodiment of the present application.
  • FIG. 10 is a schematic diagram of the propagation path of blue light with an incident angle of zero degrees in the light guide in the embodiment of the present application;
  • FIG. 11 is a schematic diagram of another structure of a two-dimensional grating in the embodiment of the present application.
  • FIG. 12 is a schematic diagram of another structure of a two-dimensional grating in the embodiment of the present application.
  • FIG. 13 is a schematic structural diagram of a near-eye display device in an embodiment of the present application.
  • FIG. 14 is another schematic structural diagram of a near-eye display device in an embodiment of the present application.
  • the light guide As the main component of the near-eye display device, the light guide has a greater impact on the performance of the near-eye display device. The most important thing is to increase the viewing angle that the light guide can support, which plays a decisive role in increasing the screen size that the near-eye display device can transmit.
  • a color picture usually includes red light, green light and blue light. Different colors of light have different wavelengths, and waveguides have different transmission paths for different colors of light.
  • the light guide in order to ensure a larger viewing angle, the light guide needs to include at least two light guide plates 110 with gratings working together to ensure that the images corresponding to the three colors of light are completely transmitted.
  • the cost of this solution is relatively high, and the structure of the light guide is relatively complicated, and it occupies more space, which is not conducive to simplifying the structure of the near-eye display device, and is not conducive to promoting the miniaturization of the near-eye display device.
  • the present application provides a light guide and a near-eye display device, so that a light guide with a grating can be used to transmit images, the structure of the light guide is simplified, the cost is reduced, and the viewing angle can be increased. Specific embodiments are listed below to illustrate the structure of the light guide and the near-eye display device in the embodiments of the present application.
  • FIG. 1 is a schematic diagram of a front structure of a light guide in an embodiment of the present application
  • FIG. 2 is a schematic diagram of a lateral structure of a light guide in an embodiment of the present application.
  • the light guide 100 in the embodiment of the present application includes a light guide plate 110 and a two-dimensional grating 120, wherein the two-dimensional grating 120 is located on the surface of the light guide plate 110, specifically, the two-dimensional grating 120 and the light guide plate 110 may be an integral structure, that is, the above-mentioned two-dimensional grating 120 is processed on the surface of the light guide plate 110 .
  • the two-dimensional grating 120 includes a plurality of grating units 121, and the plurality of grating units 121 are arranged along the first direction m and the second direction n, specifically, they may be arranged in a planar shape. Please refer to FIG.
  • the plurality of grating units 121 are arranged along the first direction m at intervals of a first distance p m , and are arranged along a second direction n at intervals of a second distance P n , that is to say, the plurality of grating units 121 can be Considered as multiple rows of grating units 121 extending along the first direction m, the multiple rows of grating units 121 are arranged in parallel and along the second direction n, and the distance between adjacent grating units 121 in each row of grating units 121 is the first distance Pm; multiple grating units 121 can also be regarded as multiple rows of grating units 121 extending along the second direction n, multiple rows of grating units 121 are arranged in parallel and along the first direction m, adjacent grating units in each row of grating units 121 The distance between 121 is the second distance Pn.
  • the above-mentioned two-dimensional grating 120 includes a light-emitting area 140 and a light-incoming area 130 arranged in sequence along the third direction y, the fourth direction x is perpendicular to the above-mentioned third direction y, the first direction m, the second direction n, and the third direction y Any two directions in the same plane as the fourth direction x are not coincident.
  • the third direction y of the above-mentioned light-emitting area 140 towards the light-incoming area 130 is the Y axis
  • the fourth direction x is the X-axis to establish a rectangular coordinate system.
  • the above-mentioned first direction m and second direction n It does not overlap with the rectangular coordinate system and has a certain included angle, so that it is convenient to form the required grating vector.
  • the grating unit of the above-mentioned two-dimensional grating can diffract one beam of incident light into at least three beams of outgoing light.
  • one incident ray can be understood as one ray vector entering the grating unit
  • three outgoing rays can be understood as three ray vectors exiting the grating unit.
  • the light spot of each pixel can form three light spots after being diffracted by the grating unit.
  • the grating unit in the light incident region of the light guide receives the light, and the above grating unit is used to diffract one beam of incident light into at least three beams of outgoing light.
  • the light is diffused by the grating unit in the light guide plate, and is emitted from the grating unit in the light exit area.
  • the grating unit diffracts one beam of incident light into at least three beams of outgoing light for transmission. Specifically, four beams of outgoing light, five beams of outgoing light or six beams of outgoing light can be diffracted.
  • Applications are not limited.
  • the light entering the light guide has multiple transmission paths, which can allow part of the field of view to escape from the light guide when it is transmitted through the main path, and then use the compensation path to compensate for the escaped field of view, so that a light guide plate can be used to support a larger Transmission of field of view. That is to say, the light guide in this solution can transmit a larger viewing angle, and the structure of the light guide is relatively simple.
  • the two-dimensional grating 120 is located on the surface of the light guide plate 110, which facilitates the preparation of the above-mentioned two-dimensional grating 120, but in practical applications, please refer to FIG. 2, all the grating units 121 of the above-mentioned two-dimensional grating 120 can be located The same side surface of the light board 110 .
  • FIG. 3 is another schematic diagram of the lateral structure of the light guide in the embodiment of the present application. As shown in FIG. The rest of the grating units 121 are located on the other side surface of the light guide plate 110 , which is not limited in the present application. FIG. 3 is only an exemplary illustration. In practical applications, the position of the grating unit 121 in a suitable area can be selected according to requirements.
  • the above-mentioned two-dimensional gratings 120 on both sides of the light guide plate 110 may overlap a part to improve image uniformity.
  • the dotted lines extending along the first direction m and the dotted lines extending along the second direction n in the figure may be regarded as auxiliary lines for preparing the two-dimensional grating 120 , rather than actual structures.
  • the aforementioned auxiliary lines respectively extend along the first direction m and the second direction n, and the point where the auxiliary lines intersect is the position where the grating unit 121 is disposed.
  • Gratings are usually formed by periodic subwavelength scale refractive index modulations.
  • K space that is, wave vector space
  • Diffraction gratings are usually characterized by grating vectors, which can be defined as is the grating period.
  • the ray behavior of light rays can also be represented by three-dimensional space vectors.
  • the light direction change caused by the grating can be described by the vector sum, that is:
  • M is the diffraction order of the grating vector of the deflected light
  • M is an integer, which can be positive, negative or zero.
  • FIG. 4 is a schematic diagram of the wave vector space structure of the light guide in the prior art. Please refer to FIG. transmission within the light board 110 .
  • the radius of the inner dashed circle is n 0 , where n 0 is the refractive index of air, and the radius of the outer dashed circle is equal to n 1 , where n 1 is the refractive index of the light guide 100 . Only when the wave vector of the light falls into the circle between the inner dotted circle and the outer dotted circle can it propagate in the light guide 100 , and it is possible to exit from the light emitting area 140 to the eyebox area.
  • the light guide 100 is to be used to transmit a picture 01 having a red light field of view 011 , a blue light field of view 013 and a green light field of view 012 , the light wavelengths of the three colors are different.
  • the integrity of the field of view that is, the entire field of view can fall into the above-mentioned ring, it is necessary to sacrifice a certain field of view, resulting in a smaller field of view of the picture 01 transmitted by the light guide 100 .
  • Figure 5 is a schematic diagram of the local distribution of the grating unit in the embodiment of the present application, as shown in Figure 5, the grating unit 121 includes a first grating vector and the second raster vector and combined raster-vector where the first raster vector perpendicular to the first direction m, it can be inclined towards the direction of the light-emitting area 140, the second grating vector perpendicular to the second direction n, or inclined towards the direction of the light exit area 140, the first grating vector and the second raster vector is the basic grating vector of grating unit 121, and all combined grating vectors are based on the above first raster-vector and the second raster vector get.
  • the above combined raster vector is the first grating vector of the diffraction order M1 and the second grating vector of the diffraction order M2
  • the vector sum of ; among them, M1 and M2 are integers.
  • the acute angle between the first direction m and the fourth direction x is ⁇ 1
  • the acute angle between the second direction n and the fourth direction x is ⁇ 1
  • the first grating vector The included angle with the second direction n is ⁇ 1
  • the included angle with the first direction m is ⁇ 2
  • the above-mentioned first grating vector second raster vector sum raster vector The formula can be referred to as follows:
  • the light guide 100 also includes a light-diffusing area located between the light-incoming area 130 and the light-out area 140. is a fixed area in the light guide 100 . That is, the area where the image 01 enters the light guide 100 is the light incident area 130 , the area where the image 01 exits the light guide 100 is the light output area 140 , and the middle is the light expansion area.
  • the light incident region 130 receives light, and the above-mentioned light enters the light guide plate 110 from the grating unit 121 of the light incident region 130 of the light guide 100 , and is totally reflected on the surface of the light guide plate 110 away from the two-dimensional grating 120 .
  • One side of the grating unit 121 of the two-dimensional grating 120 expands the light, and after multiple reflections, it is derived from the grating unit 121 of the light exit area 140, so that the picture 01 of the light incident area 130 entering the light guide 100 can be enlarged and then exported from the light exit area 140, so that The user can watch screen 01.
  • each time the light hits the grating unit 121 it is divided into several parts, which are respectively subjected to the first grating vector of the grating unit 121.
  • second raster vector sum raster vector enabled for transmission. That is to say, the grating unit 121 of the light incident area 130 is in the first grating vector second raster vector sum raster vector coupled into the light guide plate 110 under the enabling action, total reflection occurs on the surface of the light guide plate 110 opposite to the light incident area 130 and the light expansion area, and then enters the light incident area 130 and the grating unit 121 of the light expansion area, Again in raster unit 121 the first raster vector second raster vector and/or combined raster-vector Under the action of enabling, it shoots back into the light guide plate 110 until it shoots to the grating unit 121 of the light-emitting area 140, and then in the first grating vector second raster vector sum raster vector Under the enabling action of , it exits the
  • the first direction m, the second direction n, the third direction y and the fourth direction x are located on the same plane and any two directions do not coincide, that is, the first direction m and the second direction n are respectively If the x-axis or the y-axis has an acute angle with an absolute value not equal to 0° or an absolute value not equal to 90°, then the angle can be any angle between (0°, 90°). As shown in Figure 4, the first direction m and the second direction n are inclined towards both sides of the fourth direction x respectively, and the acute angle between the first direction m and the fourth direction x is ⁇ 1 , and the second The acute included angle between the direction n and the fourth direction x is ⁇ 2 .
  • the acute angle included between the first direction m and the fourth direction x is ⁇ 1 and satisfies: 10 ⁇ 1 ⁇ 80.
  • the value of ⁇ 1 above can be 20°, 25.5°, 28°, 30°, 40°, 45°, 48°, 50°, 55°, 59°, 60°, 64°, 65°, 70° or 75°, etc., which are not limited in this application.
  • the acute angle ⁇ 2 between the second direction n and the fourth direction x satisfies: 10 ⁇ 2 ⁇ 80, specifically, the value of ⁇ 2 can be 18°, 20°, 25°, 28° , 30°, 35°, 40°, 45°, 48°, 50°, 55°, 59°, 60°, 64°, 65°, 70° or 75°, etc., which are not limited in this application.
  • the above-mentioned first direction m and second direction n may also be non-axisymmetric with respect to the orthogonal coordinate system, as long as the first direction m intersects with the second direction n and faces the two sides of the third direction y respectively. It only needs to be tilted sideways, which is not limited in this application.
  • only the first direction m and the second direction n are axisymmetric based on the orthogonal coordinate system as an example for illustration.
  • the light guide 100 has different grating vectors for different wavelengths of light. A specific embodiment is listed below.
  • the light guide 100 in this embodiment transmits a picture 01 including red light, green light and blue light.
  • a picture 01 including red light, green light and blue light.
  • Fig. 6 is a schematic structural diagram of light guide to picture transmission in the embodiment of the present application.
  • the red light in frame 01 is at the first raster vector of raster unit 121 second raster vector and the first combined raster vector
  • all the red light of the picture 01 can be coupled into the light guide 100, and after the light is expanded, it can be coupled out of the light guide 100 from the light output area 140, so as to ensure that the red light field of view 011 is not lost.
  • the blue light field of view 013 and the green light field of view 012 will be lost, such as areas a and b in the figure.
  • Fig. 7 is a schematic diagram of the red light transmission path of the light guide to the picture in the embodiment of the present application.
  • the red light transmission path includes the above-mentioned first grating vector second raster vector and the first combined raster vector
  • the starting point of each grating vector among the figure all corresponds to a grating unit 121, and the transmission path shown in (a) among Fig.
  • the red light encounters the first grating unit 121, is subjected to the first resultant grating vector Influenced by the enable, it shoots to the second grating unit 121, where the grating unit 121 is subjected to the reversed second grating vector Influenced by the enable, and shoot to the third grating unit 121, where the third grating unit 121 is subjected to the reversed first grating vector Influenced by the enable, the light is emitted from the light guide 100 , so that the red light in the screen 01 can be emitted from the light guide 100 .
  • the transmission paths shown in (b) in Figure 7 are, in turn, and Therefore, the red light in the picture 01 can be emitted from the light guide 100; the transmission paths shown in (c) in FIG. 7 are, in turn, and Thus, the red light in the picture 01 can be emitted from the light guide 100; the transmission paths shown in (d) in FIG. 7 are, in turn, and Therefore, the red light in the picture 01 can be emitted from the light guide 100 .
  • Fig. 8 is a schematic diagram of the propagation path of red light with an incident angle of zero degree in the light guide in the embodiment of the present application. Please refer to Fig. 6 to Fig. 8 .
  • the first grating unit 121 in the light incident area 130, the first grating vector second raster vector and the first combined raster vector Influenced by enabling several parts are coupled into the light guide plate 110, and then each part of the light respectively encounters the second grating unit 121 in the light-diffusing area, and the required grating vector of the second grating unit 121 is enabled
  • the light guide 100 is emitted from the light exit area 140.
  • the vector sum of the grating vectors affected by the enabling of each part of light in the three grating units 121 is zero, so that the red light can pass through the light guide 100 for light expansion and exit the light guide 100 .
  • picture 01 includes red light field of view 011 , green light field of view 012 and blue light field of view 013 .
  • the red light field of view 011 is transmitted and the angular FOV of the red light field of view 011 is guaranteed to be the maximum, the green light field of view 012 and the blue light field of view 013 will have the problem of missing field of view.
  • the green light field of view Areas a and b of 012 and Blu-ray field of view 013 are the missing fields of view when the four main paths are used for transmission.
  • the transmission path of the two-dimensional grating 120 in the technical solution of this application also includes a compensation path , specifically, in addition to including the first grating vector in the compensation path second raster vector and the first combined raster vector
  • other combined raster vectors can also be included
  • the above-mentioned compensation path will be described by enumerating a specific embodiment by using the Blu-ray in the transmission picture 01 .
  • Fig. 9 is a schematic diagram of the compensation path of the Blu-ray field of view in the transmission screen of the embodiment of the present application.
  • the compensation path can also be used to compensate for the missing blue light field of view a region and blue light field of view b region.
  • the combined grating vector of the grating unit 121 You can also include a second combined raster vector third combined raster vector Fourth combined raster vector and the fifth combined raster vector
  • the first compensation path as shown in (a) in FIG. 9 can be used to compensate for the missing area a of the blue light field of view.
  • the above-mentioned missing area a of the blue light field of view can be compensated.
  • the second compensation path shown in (b) in FIG. 9 can be used to compensate for the missing area b of the blue light field of view.
  • Figure 10 is a schematic diagram of the propagation path of blue light with an incident angle of zero degrees in the light guide in the embodiment of the present application. Please combine Figures 9 and 10.
  • the first raster element 121 of region 130 can be affected by the first raster vector second raster vector first composite raster vector second composite raster vector Fourth combined raster vector.
  • the function of enabling, several parts are coupled into the light guide plate 110, and then each part of the light respectively encounters the second grating unit 121 in the light diffusion area, under the action of the required grating vector of the second grating unit 121 , is emitted to the third grating unit 121 , and is emitted from the light guide 100 from the light exit area 140 under the action of the required grating vector of the third grating unit 121 .
  • the vector sum of the grating vectors of the three grating units 121 that each part of light passes through is zero, so that the blue light can pass through the light guide 100 to be expanded and emitted.
  • the blue light in this application can also be propagated through the compensation path in addition to the main path.
  • the light guide 100 can also use the main path and the compensation path for transmission.
  • the compensation path of the green field of view can be the same as or different from the compensation path of the blue field of view, which is not limited in this application.
  • the red light field of view 011 can realize complete transmission only by using the main path.
  • the red light field of view 011 can also use the main path to cooperate with compensation. path for transmission.
  • the light guide 100 has a two-dimensional grating 120, which can form basic grating vectors in two directions. More directions and sizes of grating vectors can be formed, and the above-mentioned more grating vectors can form the main path and the compensation path, and the transmission of a larger viewing angle can be realized when the light passes through the above-mentioned main path and the compensation path.
  • This solution can use a piece of light guide 100 to realize the transmission of light of each color in the picture 01, and can ensure a larger viewing angle. Therefore, this solution can also simplify the structure of the light guide 100 while increasing the viewing angle. The cost is reduced, and it is beneficial to realize the miniaturization of the near-eye display device using the light guide 100 .
  • the first grating vector second raster vector and the individual combined raster vectors The specific direction and size of , as well as the specific values of M1 and M2, are intended to illustrate in principle the working process of the grating vector of the light guide 100 with the two-dimensional grating 120 in the embodiment of the present application, not as a single specific According to the actual situation, those skilled in the art can choose to design the above-mentioned first grating vector second raster vector and the individual combined raster vectors The specific direction and size of , and the specific values of M1 and M2.
  • the above-mentioned first raster vector and the second raster vector The specific direction and size of are determined by the periodic arrangement scheme of the gratings of the two-dimensional grating 120, and each combined grating vector
  • the specific orientation and magnitude can be specified in the first raster vector and the second raster vector
  • the design is carried out by designing the structure of the grating unit 121, for example, designing the diffraction energy level M1 and the diffraction energy level M2.
  • the incident angle includes the angle of the light of the entire screen 01 , which will not be described one by one here.
  • the incident angle of the ray is other than 0, then the ray should start from the first grating vector second raster vector sum raster vector
  • the raster vectors corresponding to the sum of the initial vectors of the respective target rays are transmitted.
  • the initial vector of the ray is Then the target ray should start from as well as
  • the corresponding raster vector transmission is, in short, transmitted under the enabling function of the corresponding raster vector, which will not be described in detail here.
  • part of the field of view can be allowed to escape from the light guide 100 , but a compensation path can be used to compensate for the escaped field of view.
  • the above-mentioned diffraction energy levels can be selected as high-order diffraction energy levels.
  • the above-mentioned diffraction energy levels M1 can be -3, -2, -1, 0, 1, 2 and 3;
  • Diffraction order M2 includes -3, -2, -1, 0, 1, 2 and 3.
  • the diffraction energy level can be higher, for example, the diffraction energy level M1 can be -5, -4, 4, and 5, etc.; the diffraction order M2 includes -5, -4, 4, and 5, etc., so the advanced diffraction energy can be fully utilized Level, you can get more combined raster vector In order to obtain the compensation path that meets the compensation demand. It is worth noting that the diffraction energy level here refers to the diffraction energy level in the wave vector space.
  • the light guide 100 includes only one light guide plate 110 to realize the transmission of the picture 01 with a larger viewing angle, which not only simplifies the structure of the light guide 100, but also expands the viewing angle.
  • all the grating units 121 of the two-dimensional grating 120 may have the same shape, so as to facilitate the processing and preparation of the above-mentioned two-dimensional grating 120 .
  • the shape of the grating unit 121 in the drawings of the embodiment of the present application is represented by a simple circle, polygon, etc.
  • the above-mentioned shapes are used to indicate that there are differences in the shape and size of the grating unit 121, but they do not represent the shape of the grating unit 121.
  • the actual shape and size of the unit 121 are all circular, which only means that the shapes of the grating units 121 are the same, but does not mean that the actual shapes of the grating units 121 are circular.
  • Fig. 11 is a schematic diagram of another structure of the two-dimensional grating in the embodiment of the present application. Please refer to Fig. 11.
  • the two-dimensional grating 120 includes at least two sub-regions, and the shapes of the grating units 121 in adjacent sub-regions are different.
  • the shape of the grating unit 121 is the same.
  • the sub-regions in this embodiment are divided according to the different shapes of the grating units 121 of the sub-regions. For example, in the embodiment shown in FIG.
  • the grating unit 121 in the A sub-region and the C sub-region is elliptical, although the form of the grating unit 121 in the A sub-region and the C sub-region is the same, but the two are not adjacent, and the forms of the grating units 121 of the two
  • the form of the grating unit 121 is different from that of the sub-region adjacent to itself.
  • the specific form of the grating unit 121 in the embodiment of the present application is not limited, and may specifically be blazed, inclined, rhombus, binary or pillar.
  • Fig. 12 is a schematic diagram of another structure of the two-dimensional grating in the embodiment of the present application. Please refer to Fig. 12.
  • the above-mentioned two-dimensional grating 120 may also include at least two sub-regions, the first distance Pm of adjacent sub-regions is different, and the first distance Pm of adjacent sub-regions is different.
  • the second distance Pn of the regions is different.
  • the sub-regions in this embodiment are divided according to the distances between the grating units 121 of the sub-regions.
  • the first grating vector can be provided and the second raster vector
  • more possible composite grating vectors can be formed, and then a combination of multiple grating paths can be formed, so that more light rays are emitted from the light exit area 140 and the viewing angle is increased.
  • the two-dimensional grating 120 may include two sub-regions, respectively a first sub-region 150 and a second sub-region 160, and the above-mentioned second sub-region 160 and the first sub-region 150 are along the third direction y are arranged in sequence.
  • the light entrance area 130 and the light exit area 140 are located in the first sub-area 150
  • the second sub-area 160 is located on the side of the light exit area 140 away from the light entrance area 130
  • the first distance Pm of the first sub-area 150 is greater than that of the second sub-area 160.
  • the first distance Pm, the second distance Pn of the first sub-region 150 is greater than the second distance Pn of the second sub-region 160 , that is, the grating period of the second sub-region 160 is smaller than the grating period of the first sub-region 150 .
  • This solution can reduce the loss of light energy in the light guide 100 and improve the light transmission efficiency of the light guide 100 .
  • the light enters the light guide 100 from the light incident region 130 transmits and expands the light in the light guide 100 , and exits from the light exit region 140 .
  • there is still some light leakage on the side of the light exit region 140 away from the light entrance region 130 that is, there is a part of light leakage in the second subregion 160 .
  • the light leakage refers to light that cannot enter the human eye.
  • the grating period of the grating unit 121 of the second sub-region 160 is relatively small, then the formed grating vector can return the light transmitted to the second sub-region 160 to the first sub-region 150, for example Between the light incident region 130 and the light exit region 140 , the grating unit 121 can be used again to transmit and exit the light exit region 140 , thereby reducing the loss of light energy in the light guide 100 and improving the light transmission efficiency of the light guide 100 .
  • the first distance Pm of the first subregion 150 is T times the first distance Pm of the second subregion 160
  • the second distance Pn of the first subregion 150 is the first distance Pm of the second subregion 160. Two times T times the distance Pn, where T is a positive integer of at least 2.
  • the first distance Pm between the grating units 121 in the above-mentioned first sub-region 150 may be equal or different, and the second distance Pn may be equal or different.
  • the first distance Pm between the grating units 121 in the second sub-region 160 may be equal or not, and the second distance Pn may be equal or not. That is to say, the above-mentioned first sub-region 150 can be divided into sub-regions, and the second sub-region 160 can also be divided into sub-regions, which is not limited in this application.
  • the first distance Pm of the above-mentioned two-dimensional grating 120 is equal, and the second distance Pn is also equal, so as to facilitate the processing and preparation of the two-dimensional grating 100.
  • Grating 120 is equal
  • the value of the first distance Pm is between 100 nm and 1000 nm
  • the value of the second distance Pn is between 100 nm and 1000 nm.
  • the value of the above-mentioned first distance Pm is between 200nm and 600nm, specifically 300nm, 400nm, 430.5nm or 600nm, etc.
  • the value of the second distance Pn is between 200nm and 600nm, specifically 250nm, 250nm, 300nm, 400nm, 442.5nm, 500nm, 550nm or 600nm and other values. This application is not limited.
  • FIG. 13 is a schematic structural diagram of a near-eye display device in an embodiment of the present application.
  • the near-eye display device in the embodiment of the present application includes any of the above-mentioned embodiments
  • the light guide 100 further includes a housing 200 and an optical machine 300 , wherein the optical machine 300 and the light guide 100 are disposed on the housing 200 .
  • the light engine 300 is used to generate light, and shoot the light to the light incident area 130 of the light guide 100 , and the light guide 100 emits the light after expanding the light, so that the light is received by human eyes, so that the user can obtain the screen 01 .
  • the light above can be the light of the picture 01, which can include red light, green light and blue light.
  • the light guide 100 can use a light guide plate 110 to make the picture of the light of the above three colors 01 is emitted with a larger viewing angle, thereby simplifying the structure of the near-eye display device, increasing the viewing angle of the near-eye display device, and improving user experience.
  • the above-mentioned near-eye display device may be augmented reality (augmented reality, AR) glasses, or virtual reality (virtual reality, VR) glasses, etc., which are not specifically limited here.
  • augmented reality augmented reality, AR
  • virtual reality virtual reality, VR
  • the housing 200 of the near-eye display device in the embodiment of the present application may include structures such as temples 210 (or straps) and a mirror frame 220 , and the temples 210 and the mirror frame 220 may be arranged in any reasonable form.
  • the optical machine 300 in the near-eye display device includes a laser 310 and a scanner 320, wherein the laser 310 emits light, and the scanner 320 is used to scan the light emitted by the laser 310, and This light is directed towards the light guide 100 .
  • a laser scanning system composed of a laser 310 and a scanner 320 is used as the projector 300, which has the advantages of high contrast, small size, and low power consumption.
  • the optical machine 300 can also be other systems, for example: liquid crystal on silicon (Liquid Crystal on Silicon, LCOS) optical machine 300 or digital processing (Digital Light Processing, DLP) optical machine 300, etc., Specifically, there is no limitation here.
  • liquid crystal on silicon Liquid Crystal on Silicon, LCOS
  • DLP Digital Light Processing
  • FIG. 13 mainly places the optical machine 300 on the mirror frame 220 .
  • Figure 14 is a schematic diagram of another structure of the near-eye display device in the embodiment of the present application, please refer to Figure 14, but in practical applications, the optical machine 300 can also be set on the temple 210, the position of the optical machine 300 in this application It is not limited, it is only necessary to arrange the positions of the light machine 300 and the light guide 100 reasonably, so that the light incident area 130 of the light guide 100 is opposite to the light output area 140 of the light machine 300, and the light output area 140 of the light guide 100 is in line with the area where the human eye is located. It can be compared, and will not be described in detail here.

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Abstract

一种光导（100）及近眼显示装置，光导（100）包括导光板（110）和设置于导光板（110）表面的二维光栅（120）。二维光栅（120）包括多个排布呈面状的光栅单元（121），光栅单元（121）沿第一方向间隔第一距离排布，沿第二方向间隔第二距离排布，且第一方向和第二方向相交。二维光栅（120）包括沿第三方向排布的出光区域（140）和入光区域（130），第四方向垂直于第三方向。第一方向、第二方向、第三方向和第四方向位于同一平面任意两个方向不重合。二维光栅（120）的光栅单元（121）可以将一束入射光线衍射成至少三束出射光线，使得光线的传输路径包括主路径和补偿路径，以实现较大视场的画面传输。

Description

光导及近眼显示装置
相关申请的交叉引用
本申请要求在2021年05月19日提交中国专利局、申请号为202110546093.8、申请名称为“光导及近眼显示装置”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
本申请涉及光学器件技术领域，尤其涉及到一种光导及近眼显示装置。
背景技术
视觉是人类获取外界信息的最主要的感官，近年来，学术界和工业界出现了多种近眼显示装置。尽管技术手段不完全相同，但是近眼显示装置都在沿着用户体验的方向来优化与演进，主要包括增大视场、提高分辨率、提高色域以及括大眼动范围等。其中，增大视场(field of view，FOV)的方式主要是改进光导，FOV即为用户能够看到的虚拟画面的范围。
一般来说，FOV范围越大，那么用户能够看到的虚拟画面的范围也就越大。因此，为了在将多种颜色的光线限制于光导内的同时增大FOV范围，目前较为直观的做法是光导包括多片导光板，每片导光板传输一小段光谱范围，但该做法的坏处是成倍地增加光导的导光板的数目，导致增加光导成本和重量，而且组装工艺较为复杂，不适合实现极简外形的近眼显示装置的要求。
发明内容
本申请提供了一种光导及近眼显示装置，以增大光导可以支撑的视场角，且可以简化光导的结构。
第一方面，本申请提供了一种光导。该光导包括导光板和二维光栅，二维光栅具体设置于导光板的表面，可以与导光板为一体成型结构。其中，二维光栅包括多个排布呈面状的光栅单元，具体的，光栅单元沿第一方向间隔第一距离排布，沿第二方向间隔第二距离。上述第一方向和第二方向相交。上述二维光栅包括沿第三方向排布的出光区域和入光区域，第四方向垂直于第三方向，可以认为上述第三方向为直角坐标系的y轴方向，第四方向为直角坐标系的x轴方向。上述第一方向、第二方向、第三方向和第四方向位于同一平面任意两个方向不重合。也就是说第一方向和第二方向分别与直角坐标系的坐标轴呈一定的夹角。该夹角不为0°或者90°。上述光栅单元用于将一束入射光线衍射成至少三束出射光线。
该技术方案中，光导的入光区域的光栅单元接收光线，上述光栅单元用于将一束入射光线衍射成至少三束出射光线。光线在导光板内经光栅单元的扩光，从出光区域的光栅单元射出。该方案中，当光线射至光栅单元之后，光栅单元将一束入射光线衍射成至少三束出射光线进行传输，具体可以衍射出四束出射光线，五束出射光线或者六束出射光线等， 本申请不做限制。总之，射入该光导的光线具有多种传输路径，可以允许部分视场在主路径传输时逃逸出光导，然后利用补偿路径来补偿逃逸出去的视场，从而可以利用一个导光板支撑较大的视场角的传输。也就是该方案中的光导既可以传输较大的视场角，光导的结构也较为简单。
具体设置上述二维光栅时，二维光栅排布的光栅单元可以生成第一光栅矢量、第二光栅矢量和多个合光栅矢量。其中，第一光栅矢量垂直于第一方向，第二光栅矢量垂直于第二方向，合光栅矢量为衍射级次M1的第一光栅矢量和衍射级次M2的第二光栅矢量的矢量和；其中，衍射级次M1和衍射级次M2为整数，可以为正整数、负整数或者零，具体取值本申请不做限制。入光区域的光栅单元接收光线，光线在导光板内经光栅单元的扩光之后，从出光区域的光栅单元射出。光线射至光栅单元之后，受第一光栅矢量、第二光栅矢量和合光栅矢量的作用下传输，光线传输过程中受到的光栅矢量的矢量和为零。具体的，光栅单元的合光栅矢量的数量不做限制，可以具有多个合光栅矢量，因此，第一光栅矢量、第二光栅矢量和合光栅矢量可以形成多条光传输路径。光线射至光栅单元时，可以衍射成至少三束在第一光栅矢量、第二光栅矢量和合光栅矢量的影响下形成的出射光线。可以允许部分视场在主路径传输时逃逸出光导，然后利用补偿路径来补偿逃逸出去的视场，从而可以利用一个导光板支撑较大的视场角的传输。也就是该方案中的光导既可以传输较大的视场角，光导的结构也较为简单。
具体设置光栅单元的位置时，第一方向与第四方向的锐角夹角可以位于10°至80°之间，第二方向与第四方向的锐角夹角可以位于10°至80°之间。
具体设置上述光导时，光栅单元排布的第一方向和第二方向相对于第三方向对称。也就是说，第一方向和第二方向朝向第三方向的两侧，且与第三方向的夹角相等。该方案中光栅单元的排布方式较为规则，且第一光栅矢量、第二光栅矢量和合光栅矢量的方向较为对称和规则，比较容易使得光线传输过程中疏导的光栅矢量的矢量和为零。
具体的技术方案中，通过合理的设计光栅单元的结构，可以使得上述衍射级次M1包括-3、-2、-1、0、1、2和3，衍射级次M2包括-3、-2、-1、0、1、2和3。该方案中的衍射级次指的是波矢空间的衍射级次，衍射级次较高，从而便于形成多种合光栅矢量，以得到满足补偿需求的补偿路径。
采用本申请技术方案中的光导，可以支持视场角至少为60°的画面的传输，以提高使用该光导的近眼显示装置的视场角，提升用户使用体验。
具体设置二维光栅时，二维光栅包括至少两个子区域。相邻子区域的光栅单元的形态不同，而同一子区域的光栅单元的形态相同。该方案可以通过合理的设计光栅单元的形态，可以获取不同的衍射能级，从而设计合理的主路径和补偿路径。
此外，在具体设置上述二维光栅时，还可以使二维光栅的多个光栅单元形态相同。也就是光导的表面设置的所有光栅单元的形态都一样，从而便于简化光导的制备工艺。
值得说明的是，本申请实施例中，二维光栅设置于导光板的表面，可以使二维光栅位于导光板的同一侧表面。或者，可以使的二维光栅的一部分区域位于一侧表面，其余部分区域位于另一侧表面。
上述二维光栅还可以包括至少两个子区域，相邻的子区域的第一距离不同，相邻的子区域的第二区域不同。也就是说，不同子区域的光栅周期不同，从而便于形成不同的光栅矢量，以增加可以选择的光栅矢量。
具体的技术方案中，可以使二维光栅包括第一子区域和第二子区域。入光区域和出光区域位于第一子区域，第二子区域位于出光区域远离入光区域的一侧。上述第一子区域的第一距离大于第二子区域的第一距离，第一子区域的第二距离大于第二子区域的第二距离。也就是说，第二子区域的光栅周期小于第一子区域的光栅周期。该方案可以减少光导中的光线能量的损失，提高光导传输光线的效率。
上述第一距离具体可以位于200nm至600nm之间，第二距离具体可以位于200nm至600nm之间。可以根据实际需求设置上述第一距离和第二距离的取值，本申请不做限制。
第二方面，本申请还提供了一种近眼显示装置。该近眼显示装置包括壳体、光机，以及上述任一技术方案中的光导。其中，光机和光导设置于壳体，光机用于生成光线，并将生成的光线射至光导的入光区域。该方案中的近眼显示装置的视场角较大，且结构较为紧凑，有利于实现小型化。
近眼显示装置的具体类型不做限制，可以为虚拟现实眼镜或者增强现实眼镜。只要需要利用光导传输画面的近眼显示装置都在本申请保护范围内。
具体设置上述光机时，光机可以包括激光器、扫描器和控制器。其中，光机的扫描器用于扫描激光器发出的入射光线并发送给光导的入光区域。
光机的具体类型也不做限制，例如，上述光机可以为硅基液晶光机或数字光处理光机。
上述光机生成的光线包括红光、绿光和蓝光。该方案中的光导可以实现三种颜色的画面的大视场的传播，且结构较为简单。
附图说明
图1为本申请实施例中光导的一种正视结构示意图；
图2为本申请实施例中光导的一种侧向结构示意图；
图3为本申请实施例中光导的另一种侧向结构示意图；
图4为现有技术中光导的波矢空间结构示意图；
图5为本申请实施例中光栅单元的局部分布示意图；
图6为本申请实施例中光导对画面传输的一种结构示意图；
图7为本申请实施例中光导对画面的红光传输路径示意图；
图8为本申请实施例中入射角为零度的红光在光导内传播路径示意图；
图9为本申请实施例传输画面中蓝光视场的补偿路径示意图；
图10为本申请实施例中入射角为零度的蓝光在光导内传播路径示意图；
图11为本申请实施例中二维光栅的另一种结构示意图；
图12为本申请实施例中二维光栅的另一种结构示意图；
图13为本申请实施例中近眼显示装置的一种结构示意图；
图14为本申请实施例中近眼显示装置的另一种结构示意图。
附图说明：
100-光导；                        110-导光板；
120-二维光栅；                    121-光栅单元；
130-入光区域；                    140-出光区域；
150-第一子区域；                  160-第二子区域；
01-画面；                         011-红光视场；
012-绿光视场；                    013-蓝光视场；
200-壳体；                        210-镜腿；
220-镜框；                        300-光机；
310-激光器；                      320-扫描器。
具体实施方式
以下实施例中所使用的术语只是为了描述特定实施例的目的，而并非旨在作为对本申请的限制。如在本申请的说明书和所附权利要求书中所使用的那样，单数表达形式“一个”、“一种”、“所述”、“上述”、“该”和“这一”旨在也包括例如“一个或多个”这种表达形式，除非其上下文中明确地有相反指示。
在本说明书中描述的参考“一个实施例”或“具体的实施例”等意味着在本申请的一个或多个实施例中包括结合该实施例描述的特定特征、结构或特点。术语“包括”、“包含”、“具有”及它们的变形都意味着“包括但不限于”，除非是以其他方式另外特别强调。
为了方便理解本申请实施例提供的光导及近眼显示装置，下面先介绍一下其应用场景。光导作为近眼显示装置的主要部件，对于近眼显示装置的性能具有较大的影响，最主要的是增大光导可以支撑的视场角，对于增大近眼显示装置能够传输的画面尺寸具有决定性作用。彩色画面中通常包括红光、绿光和蓝光，不同颜色的光的波长不同，波导对于不同颜色的光的传输路径也不同。现有技术中，为了保证较大的视场角，光导需要包括至少两片具有光栅的导光板110共同作用，才可以同时保证三种颜色的光对应的画面都完整的进行传输。该方案成本较高，且光导的结构较为复杂，占用的空间也较多，不利于简化近眼显示装置的结构，不利于促进近眼显示装置的小型化。为此，本申请提供了一种光导及近眼显示装置，从而可以利用一片具有光栅的光导传输画面，简化了光导的结构，降低了成本，且可以增大视场角。下面列举具体的实施例来说明本申请实施例中的光导及近眼显示装置的结构。
图1为本申请实施例中光导的一种正视结构示意图，图2为本申请实施例中光导的一种侧向结构示意图。请参考图1和图2，本申请实施例中的光导100包括导光板110和二维光栅120，其中，二维光栅120位于导光板110的表面，具体的，上述二维光栅120与导光板110可以为一体结构，就是说在导光板110的表面加工上述二维光栅120。上述二维光栅120包括多个光栅单元121，上述多个光栅单元121沿第一方向m和第二方向n排布，具体可以排布呈面状。具体请参考图1，上述多个光栅单元121沿第一方向m间隔第一距离p m排布，沿第二方向n间隔第二距离P n排布，也就是说，多个光栅单元121可以看成沿第一方向m延伸的多行光栅单元121，多行光栅单元121平行且沿第二方向n排布，每行光栅单元121中相邻的光栅单元121之间的距离为第一距离Pm；多个光栅单元121还可以看成沿第二方向n延伸的多行光栅单元121，多行光栅单元121平行且沿第一方向m排布，每行光栅单元121中相邻的光栅单元121之间的距离为第二距离Pn。上述二维光栅120包括沿第三方向y依次排布的出光区域140和入光区域130，第四方向x垂直与上述第三方向y，第一方向m、第二方向n、第三方向y和第四方向x位于同一平面中任意两个方向不重合。请参考图1，可以认为以上述出光区域140朝向入光区域130的第三方向y为Y轴，以第四方向x为X轴建立一个直角坐标系，上述第一方向m和第二方向n与直角坐标系不重叠，具有一定的夹角，从而便于形成需要的光栅矢量。
上述二维光栅的光栅单元可将一束入射光线衍射成至少三束出射光线。此处，一束入射光线可以理解成射入光栅单元的一个光线矢量，三束出射光线则可以理解成射出光栅单元的三个光线矢量。当光导应用于图像传输时，每个像素的光斑经过光栅单元的衍射后，可以形成三个光斑。该技术方案中，光导的入光区域的光栅单元接收光线，上述光栅单元用于将一束入射光线衍射成至少三束出射光线。光线在导光板内经光栅单元的扩光，从出光区域的光栅单元射出。该方案中，当光线射至光栅单元之后，光栅单元将一束入射光线衍射成至少三束出射光线进行传输，具体可以衍射出四束出射光线，五束出射光线或者六束出射光线等，本申请不做限制。总之，射入该光导的光线具有多种传输路径，可以允许部分视场在主路径传输时逃逸出光导，然后利用补偿路径来补偿逃逸出去的视场，从而可以利用一个导光板支撑较大的视场角的传输。也就是该方案中的光导既可以传输较大的视场角，光导的结构也较为简单。
具体的实施例中，二维光栅120位于导光板110的表面，则便于制备上述二维光栅120，但是在实际应用中，请参考图2，上述二维光栅120所有光栅单元121可以均位于导光板110的同一侧表面。图3为本申请实施例中光导的另一种侧向结构示意图，如图3所示，可以使二维光栅120的部分区域的光栅单元121位于导光板110的一侧表面，二维光栅120其余部分的光栅单元121位于导光板110的另一侧表面，本申请对此不作限制。图3仅为一种示例性说明，实际应用中，可以根据需求选择合适区域的光栅单元121的位置。上述位于导光板110两侧表面的二维光栅120可以交叠一部分，以提高画面均匀性。
如图1所示，图中沿第一方向m延伸的虚线和沿第二方向n延伸的虚线可以认为是制备二维光栅120的辅助线，并非为实际结构。具体的，上述辅助线分别沿第一方向m延伸和第二方向n延伸，辅助线相交的点即为设置光栅单元121的位置。
光栅通常由周期性亚波长尺度的折射率调制形成。为方便起见，技术人员通常借助K空间，也即波矢空间，来理解和量化光栅对光线的偏折行为。衍射光栅通常用光栅矢量来表征，可以定义为
Figure PCTCN2022093392-appb-000001
为光栅周期。光线的射线行为也可以用三维空间矢量表示。在K空间，光栅引起的光线方向改变可以利用矢量和来描述，也即：
Figure PCTCN2022093392-appb-000002
其中，
Figure PCTCN2022093392-appb-000003
为入射至光栅的光线矢量，
Figure PCTCN2022093392-appb-000004
为经光栅偏折后的光线矢量，
Figure PCTCN2022093392-appb-000005
为光栅矢量，M为偏折光线的光栅矢量的衍射级次，M为整数，具体可以为正数、负数或者零。
也就是说，光线在具有光栅的导光板110的传播轨迹可以通过K空间来观察。图4为现有技术中光导的波矢空间结构示意图，请参考图4，对于光导100来说，光线只有进入K空间中由内虚线圆和外虚线圆围成的圆环内，才能在导光板110内传输。内虚线圆的半径为n 0，n 0为空气的折射率，外虚线圆的半径等于n 1，n 1为光导100的折射率。当光线的波矢落入到内虚线圆与外虚线圆之间的圆环内才能够在光导100中传播，才有可能从出光区域140出射到眼动范围(eyebox)区域。因此，如图4所示的现有技术情况下，要想利用光导100传播具有红光视场011、蓝光视场013和绿光视场012的画面01，三种颜色的光线波长不同，为了保证视场完整，也就是整个视场都能落入到上述圆环内，就需要牺牲一定视场角，导致光导100传输的画面01的视场角较小。
图5为本申请实施例中光栅单元的局部分布示意图，如图5所示，光栅单元121包括第一光栅矢量
Figure PCTCN2022093392-appb-000006
和第二光栅矢量
Figure PCTCN2022093392-appb-000007
以及合光栅矢量
Figure PCTCN2022093392-appb-000008
其中，第一光栅矢量
Figure PCTCN2022093392-appb-000009
垂直于第一方向m，可以朝向出光区域140方向倾斜，第二光栅矢量
Figure PCTCN2022093392-appb-000010
垂直于第二方向n， 也可以朝向出光区域140方向倾斜，第一光栅矢量
Figure PCTCN2022093392-appb-000011
和第二光栅矢量
Figure PCTCN2022093392-appb-000012
为光栅单元121的基础光栅矢量，所有的合光栅矢量
Figure PCTCN2022093392-appb-000013
都基于上述第一光栅矢量
Figure PCTCN2022093392-appb-000014
和第二光栅矢量
Figure PCTCN2022093392-appb-000015
获得。具体的，上述合光栅矢量
Figure PCTCN2022093392-appb-000016
为衍射级次M1的第一光栅矢量
Figure PCTCN2022093392-appb-000017
和衍射级次M2的第二光栅矢量
Figure PCTCN2022093392-appb-000018
的矢量和；其中，M1和M2为整数。请参考图4，第一方向m与第四方向x的锐角夹角为θ 1，第二方向n与第四方向x的锐角夹角为θ 1，第一光栅矢量
Figure PCTCN2022093392-appb-000019
与第二方向n之间的夹角为β 1，第二光栅矢量
Figure PCTCN2022093392-appb-000020
与第一方向m之间的夹角为β 2，则，上述第一光栅矢量
Figure PCTCN2022093392-appb-000021
第二光栅矢量
Figure PCTCN2022093392-appb-000022
和合光栅矢量
Figure PCTCN2022093392-appb-000023
的公式可以参考如下：
Figure PCTCN2022093392-appb-000024
Figure PCTCN2022093392-appb-000025
Figure PCTCN2022093392-appb-000026
光线射至二维光栅120时，在上述第一光栅矢量
Figure PCTCN2022093392-appb-000027
第二光栅矢量
Figure PCTCN2022093392-appb-000028
以及合光栅矢量
Figure PCTCN2022093392-appb-000029
的作用下发生衍射。具体的，在本申请实施例中，可以认为光导100还包括位于入光区域130和出光区域140之间的扩光区域，值得说明的是，上述各个区域可以依靠实际使用状态确定，而不一定是光导100中固定的区域。也就是画面01进入光导100的区域即为入光区域130，画面01从光导100射出的区域即为出光区域140，中间即为扩光区域。入光区域130接收光线，上述光线从光导100的入光区域130的光栅单元121进入到导光板110内，在导光板110背离二维光栅120的一侧表面发生全反射，在导光板110朝向二维光栅120的光栅单元121一侧扩光，多次反射后从出光区域140的光栅单元121导出，从而可以将入光区域130进入光导100的画面01放大后从出光区域140导出，以使用户可以观看画面01。具体的，光线每次射至光栅单元121之后，都分成几部分，分别受到光栅单元121的第一光栅矢量
Figure PCTCN2022093392-appb-000030
第二光栅矢量
Figure PCTCN2022093392-appb-000031
和合光栅矢量
Figure PCTCN2022093392-appb-000032
的使能进行传输。也就是说，光线在入光区域130的光栅单元121在第一光栅矢量
Figure PCTCN2022093392-appb-000033
第二光栅矢量
Figure PCTCN2022093392-appb-000034
和合光栅矢量
Figure PCTCN2022093392-appb-000035
的使能作用下耦入导光板110内，在导光板110与入光区域130和扩光区域相对的一侧表面发生全反射，然后射至入光区域130和扩光区域的光栅单元121，再次在光栅单元121的第一光栅矢量
Figure PCTCN2022093392-appb-000036
第二光栅矢量
Figure PCTCN2022093392-appb-000037
和/或合光栅矢量
Figure PCTCN2022093392-appb-000038
的使能作用下射回导光板110内，直至射向出光区域140的光栅单元121，再在第一光栅矢量
Figure PCTCN2022093392-appb-000039
第二光栅矢量
Figure PCTCN2022093392-appb-000040
和合光栅矢量
Figure PCTCN2022093392-appb-000041
的使能作用下射出导光板110。为了保证光线能够从出光区域140射出光导100，需要使每一部分光线传输过程中受到影响的光栅矢量的矢量和为零。
请继续参考图5，上述第一方向m、第二方向n、第三方向y和第四方向x位于同一平面且任意两个方向不重合，也就是第一方向m和第二方向n分别与x轴或y轴存在绝对值不等于0°或者绝对值不等于90°的锐角夹角，那么该角度可以是(0°，90°)之间的任意一个角度。如图4所示，上述第一方向m和第二方向n分别朝向第四方向x的两侧倾斜，且上述第一方向m与第四方向x之间的锐角夹角为θ 1，第二方向n与第四方向x之间的锐角夹角为θ 2。具体的，上述第一方向m与第四方向x之间的锐角夹角为θ 1满足：10≤θ 1≤80，具体的，上述θ 1的值可以为20°、25.5°、28°、30°、40°、45°、48°、50°、55°、59°、60°、64°、65°、70°或者75°等，本申请不做限制。同样，上述第二方向n与第四方向x之间的锐角夹角θ 2满足：10≤θ 2≤80，具体的，上述θ 2的值可 以为18°、20°、25°、28°、30°、35°、40°、45°、48°、50°、55°、59°、60°、64°、65°、70°或者75°等，本申请不做限制。
具体的技术方案中，上述第一方向m和第二方向n可以相对于第三方向y对称，或者说，第一方向m与第二方向n可以基于正交坐标系呈轴对称。也就是说，上述第一方向m与第四方向x之间的锐角夹角θ 1，第二方向n与第四方向x之间的锐角夹角为θ 2满足：θ 1＝θ 2。在其它的实施例中，上述第一方向m和第二方向n相对于正交坐标系也可以呈非轴对称，只要第一方向m与第二方向n相交且分别朝向第三方向y的两侧倾斜即可，本申请不做限制。而在本申请实施例中仅以第一方向m与第二方向n基于正交坐标系呈轴对称为例进行说明。
光导100针对不同波长的光线，起作用的光栅矢量不同，下面列举具体的实施例，该实施例中的光导100传输包括红光、绿光和蓝光的画面01，以入射角为0度的光线为例，来说明本申请技术方案：
图6为本申请实施例中光导对画面传输的一种结构示意图，如图6所示，光栅单元121包括第一光栅矢量
Figure PCTCN2022093392-appb-000042
第二光栅矢量
Figure PCTCN2022093392-appb-000043
和第一合光栅矢量
Figure PCTCN2022093392-appb-000044
也就是M1＝M2＝1时，可以得到第一合光栅矢量
Figure PCTCN2022093392-appb-000045
即
Figure PCTCN2022093392-appb-000046
如图6所示，画面01中的红光在光栅单元121的第一光栅矢量
Figure PCTCN2022093392-appb-000047
第二光栅矢量
Figure PCTCN2022093392-appb-000048
和第一合光栅矢量
Figure PCTCN2022093392-appb-000049
的作用下，可以将画面01的所有的红光都耦入到光导100中，并在扩光之后，从出光区域140耦出光导100，以保证红光视场011不出现丢失的情况。但是，在保证红光视场011不丢失，且视场最大时，蓝光视场013和绿光视场012就会出现丢失，例如图中的a区域和b区域。
图7为本申请实施例中光导对画面的红光传输路径示意图，如图7所示，红光传输路径包括上述第一光栅矢量
Figure PCTCN2022093392-appb-000050
第二光栅矢量
Figure PCTCN2022093392-appb-000051
和第一合光栅矢量
Figure PCTCN2022093392-appb-000052
图中每个光栅矢量的起点都对应一个光栅单元121，图7中的(a)所示的传输路径，依次为
Figure PCTCN2022093392-appb-000053
和
Figure PCTCN2022093392-appb-000054
Figure PCTCN2022093392-appb-000055
值得说明的是，
Figure PCTCN2022093392-appb-000056
可以指的是第一光栅矢量
Figure PCTCN2022093392-appb-000057
方向相反而大小相同的矢量，
Figure PCTCN2022093392-appb-000058
可以指的是第二光栅矢量
Figure PCTCN2022093392-appb-000059
方向相反而大小相同的矢量；或者，也可以理解成衍射级次M1为-1的第一光栅矢量
Figure PCTCN2022093392-appb-000060
衍射级次M1为-1的第一光栅矢量
Figure PCTCN2022093392-appb-000061
也就是说，图7中的(a)所示的传输路径可以理解成，红光遇到第一个光栅单元121，受到第一合光栅矢量
Figure PCTCN2022093392-appb-000062
的使能的影响，而射向第二个光栅单元121，在该光栅单元121受到反向的第二光栅矢量
Figure PCTCN2022093392-appb-000063
的使能的影响，而射向第三个光栅单元121，在该第三个光栅单元121受到反向的第一光栅矢量
Figure PCTCN2022093392-appb-000064
的使能的影响，而射出光导100，从而画面01中的红光可以从光导100中射出。图7中的(b)所示的传输路径，依次为
Figure PCTCN2022093392-appb-000065
和
Figure PCTCN2022093392-appb-000066
从而画面01中的红光可以从光导100中射出；图7中的(c)所示的传输路径，依次为
Figure PCTCN2022093392-appb-000067
Figure PCTCN2022093392-appb-000068
和
Figure PCTCN2022093392-appb-000069
从而画面01中的红光可以从光导100中射出；图7中的(d)所示的传输路径，依次为
Figure PCTCN2022093392-appb-000070
和
Figure PCTCN2022093392-appb-000071
从而画面01中的红光可以从光导100中射出。
图8为本申请实施例中入射角为零度的红光在光导内传播路径示意图，请结合图6至图8，具体的实施例中，一束红光以0度入射角射向光导100的入光区域130第一个光栅单元121时，可以先受第一光栅矢量
Figure PCTCN2022093392-appb-000072
第二光栅矢量
Figure PCTCN2022093392-appb-000073
和第一合光栅矢量
Figure PCTCN2022093392-appb-000074
的使能的影响，分几部分耦入导光板110中，然后各部分光线分别遇到扩光区域的第二个光栅单元121，在该第二个光栅单元121的需要的光栅矢量的使能的作用下，射向第三个光栅单元121，在第三个光栅单元121的需要的光栅矢量的使能的作用下，从出光区域140射出 光导100。上述每一部分光线在三个光栅单元121的受到使能影响的光栅矢量的矢量和为零，从而可以使红光经过光导100进行扩光并射出光导100。
采用上述技术方案，利用一个光导100的三个光栅矢量，就可以实现视场角FOV至少为60°的红光的传输，可以得到较大的视场角。
请继续参考图7，由于画面01中各种颜色的光线都需要受到上述第一光栅矢量
Figure PCTCN2022093392-appb-000075
第二光栅矢量
Figure PCTCN2022093392-appb-000076
和第一合光栅矢量
Figure PCTCN2022093392-appb-000077
的使能的作用，而上述三个光栅矢量的可以形成图7中的四个传输路径，由于各种颜色的光线在光导100中都要经过上述四个传输路径进行传输，因此，称二维光栅120的上述四个传输路径为主路径。然而，请参考图6，画面01包括红光视场011、绿光视场012和蓝光视场013，由于红光、绿光和蓝光的波长不同，因此，在利用上述四个主路径将完整的红光视场011传输，且保证红光视场011角FOV达到最大时，绿光视场012和蓝光视场013会存在视场缺失的问题，例如图6中所示，绿光视场012和蓝光视场013的a区域和b区域为利用四个主路径传输时缺失的视场，为了补偿上述缺失的视场，本申请技术方案中的二维光栅120的传输路径还包括补偿路径，具体的，补偿路径中除了可以包括第一光栅矢量
Figure PCTCN2022093392-appb-000078
第二光栅矢量
Figure PCTCN2022093392-appb-000079
和第一合光栅矢量
Figure PCTCN2022093392-appb-000080
以外，还可以包括其它的合光栅矢量
Figure PCTCN2022093392-appb-000081
下面以传输画面01中的蓝光列举具体的实施例，来说明上述补偿路径。
图9为本申请实施例传输画面中蓝光视场的补偿路径示意图，请结合图6和图9，利用本申请实施例中的光导100传输画面01中的蓝光视场013时，可以利用上述主路径来进行传输，以传输图6中蓝光视场c区域和蓝光视场d区域，具体传输路径参考图7。对于蓝色视场还可以利用补偿路径来补偿缺失的蓝光视场a区域和蓝光视场b区域，具体的，为了形成上述补偿路径，光栅单元121的合光栅矢量
Figure PCTCN2022093392-appb-000082
还可以包括第二合光栅矢量
Figure PCTCN2022093392-appb-000083
第三合光栅矢量
Figure PCTCN2022093392-appb-000084
第四合光栅矢量
Figure PCTCN2022093392-appb-000085
和第五合光栅矢量
Figure PCTCN2022093392-appb-000086
例如，具体的实施例中，可以利用如图9中的(a)所示的第一补偿路径来补偿缺失的蓝光视场a区域，具体的，上述第一补偿路径对应的光栅矢量依次为
Figure PCTCN2022093392-appb-000087
和
Figure PCTCN2022093392-appb-000088
具体实施例中，可以认为第二合光栅矢量
Figure PCTCN2022093392-appb-000089
也就是M1＝-1，M2＝1，当然，在其他实施例中，可以使M1为负值，M2为正值，从而得到上述第二合光栅矢量
Figure PCTCN2022093392-appb-000090
第三合光栅矢量
Figure PCTCN2022093392-appb-000091
也就是M1＝2，M2＝0，当然，在其他实施例中，可以使M1为正值，M2为零，从而得到上述第三合光栅矢量
Figure PCTCN2022093392-appb-000092
上述
Figure PCTCN2022093392-appb-000093
利用该第一补偿路径，可以补偿上述缺失的蓝光视场a区域。同样的，可以利用如图9中的(b)所示的第二补偿路径来补偿缺失的蓝光视场b区域，具体的，上述第二补偿路径依次为
Figure PCTCN2022093392-appb-000094
和
Figure PCTCN2022093392-appb-000095
具体实施例中，可以认为第四合光栅矢量
Figure PCTCN2022093392-appb-000096
也就是M1＝1，M2＝-1，当然，在其他实施例中，可以使M1为正值，M2为负值，从而得到上述第四合光栅矢量G6；第五合光栅矢量
Figure PCTCN2022093392-appb-000097
也就是M1＝0，M2＝2，当然，在其他实施例中，可以使M2为正值，M1为零，从而得到上述第五合光栅矢量
Figure PCTCN2022093392-appb-000098
上述
Figure PCTCN2022093392-appb-000099
利用该第二补偿路径，可以补偿上述缺失的蓝光视场b区域。通过主路径配合补偿路径，可以保证将完整的蓝色视场从出光区域140射出，从而可以保证蓝色视场的完整性和视场角。
图10为本申请实施例中入射角为零度的蓝光在光导内传播路径示意图，请结合图9和图10，具体的实施例中，一束蓝光以0度入射角射向光导100的入光区域130第一个光栅单元121时，可以受第一光栅矢量
Figure PCTCN2022093392-appb-000100
第二光栅矢量
Figure PCTCN2022093392-appb-000101
第一合光栅矢量
Figure PCTCN2022093392-appb-000102
第二合光栅矢量
Figure PCTCN2022093392-appb-000103
第四合光栅矢量
Figure PCTCN2022093392-appb-000104
的使能的作用，分几部分耦入导光板110中，然后各 部分光线分别遇到扩光区域的第二个光栅单元121，在该第二个光栅单元121的需要的光栅矢量的作用下，射向第三个光栅单元121，在第三个光栅单元121的需要的光栅矢量的作用下，从出光区域140射出光导100。上述每一部分光线所经过的三个光栅单元121的光栅矢量的矢量和为零，从而可以使蓝光经过光导100进行扩光并射出。总之，本申请中的蓝光除了利用主路径进行传播以外，还可以利用补偿路径进行传播。
对于画面01中的绿色视场，光导100也可以采用主路径和补偿路径来进行传输，绿色视场的补偿路径可以与蓝色视场的补偿路径相同，也可以不同，本申请不做限制。
值得说明的是，上述实施例中，红光视场011仅仅利用主路径就可以实现完整的传输，在其它实例中，通过合理设计光栅矢量，也可以使红光视场011采用主路径配合补偿路径的方式来进行传输。
该方案中，光导100具有二维光栅120，可以形成两个方向的基础光栅矢量，在结合利用上述两个基础光栅矢量形成的合光栅矢量
Figure PCTCN2022093392-appb-000105
可以形成较多方向和大小的光栅矢量，上述较多光栅矢量可以形成主路径和补偿路径，光线经过上述主路径和补偿路径，则可以实现较大视场角的传输。该方案可以利用一片光导100来实现画面01各个颜色的光线的传输，且可以保证较大的视场角，因此，该方案在增大视场角的情况下，还可以简化光导100的结构，降低成本，且有利于实现使用该光导100的近眼显示装置的小型化。
值得说明的是，上述实施例中，第一光栅矢量
Figure PCTCN2022093392-appb-000106
第二光栅矢量
Figure PCTCN2022093392-appb-000107
以及各个合光栅矢量
Figure PCTCN2022093392-appb-000108
的具体方向和大小，以及M1和M2的具体取值，都是为了示例性的从原理上说明本申请实施例中具有二维光栅120的光导100的光栅矢量的工作过程，不作为单一的具体的方案，本领域技术人员可以在本申请文件的指导思想下，根据实际情况选择设计上述第一光栅矢量
Figure PCTCN2022093392-appb-000109
第二光栅矢量
Figure PCTCN2022093392-appb-000110
以及各个合光栅矢量
Figure PCTCN2022093392-appb-000111
的具体方向和大小，以及M1和M2的具体取值。具体的，上述第一光栅矢量
Figure PCTCN2022093392-appb-000112
和第二光栅矢量
Figure PCTCN2022093392-appb-000113
的具体方向和大小由二维光栅120的光栅的周期排布方案决定，而各个合光栅矢量
Figure PCTCN2022093392-appb-000114
的具体方向和大小，可以在第一光栅矢量
Figure PCTCN2022093392-appb-000115
和第二光栅矢量
Figure PCTCN2022093392-appb-000116
的基础上，通过设计光栅单元121的结构来进行设计，例如设计衍射能级M1和衍射能级M2。
应理解，上述实施例仅仅是从入射角为0°的入射光线进行了说明，在实际应用中，入射角包含整个画面01的光线的角度，此处不再一一描述。当光线的入射角为不等于0的其它角度时，那么该光线应当从第一光栅矢量
Figure PCTCN2022093392-appb-000117
第二光栅矢量
Figure PCTCN2022093392-appb-000118
和合光栅矢量
Figure PCTCN2022093392-appb-000119
各自与目标光线的初始矢量之和所对应的光栅矢量进行传输。比如：光线的初始矢量为
Figure PCTCN2022093392-appb-000120
那么目标光线应当从
Figure PCTCN2022093392-appb-000121
以及
Figure PCTCN2022093392-appb-000122
所对应的光栅矢量传输，总之是在对应的光栅矢量的使能作用下传输，此处不做赘述。
本申请技术方案中，可以允许部分视场从光导100中逃逸出去，但是可以利用补偿路径来补偿逃逸出去的视场。具体设计本申请技术方案中的二维光栅120时，上述衍射能级可以选用高级衍射能级，具体的，上述衍射能级M1可以为-3、-2、-1、0、1、2和3；衍射级次M2包括-3、-2、-1、0、1、2和3。甚至衍射能级可以更高，例如衍射能级M1可以为-5、-4、4和5等；衍射级次M2包括-5、-4、4和5等，因此，可以充分利用高级衍射能级，可以获取较多的合光栅矢量
Figure PCTCN2022093392-appb-000123
以得到满足补偿需求的补偿路径。值得说明的是，此处衍射能级指的是波矢空间中的衍射能级。
由于补偿路径的存在，无需使得画面01中所有颜色的视场在通过主路径传输时就都存在于光导100之内，也就是说，在利用上述主路径传输画面01时，允许视场的部分光 线从光导100中逃逸出去，然后再利用补偿路径来补偿逃逸出去的光线。因此，可以传输较大的画面01，具体的，可以使本申请技术方案中的光导100传输的画面01的视场角至少为60°。相比现有技术而言，光导100包括一个导光板110就可以实现较大视场角的画面01的传输，在简化了光导100的结构的同时，还扩大了视场角。
请参考图1，二维光栅120的所有光栅单元121的形态可以相同，从而便于加工制备上述二维光栅120。值得说明的是，本申请实施例附图中的光栅单元121的形态以简单的圆形、多边形等形状来表示，上述形状用于表示光栅单元121的形状和大小存在差异，但是并不代表光栅单元121的实际形状和大小。例如，图1中的光栅单元121的形状均为圆形，仅在于表示光栅单元121的形态相同，并不代表光栅单元121实际形状为圆形。
图11为本申请实施例中二维光栅的另一种结构示意图，请参考图11，二维光栅120包括至少两个子区域，相邻子区域的光栅单元121的形态不同，而同一个子区域内的光栅单元121形态相同。该实施例中的子区域是根据子区域的光栅单元121形态不同来划分的，例如图10所示的实施例中，二维光栅120单元包括九个子区域，分别以A～I表示，其中，A子区域与C子区域中的光栅单元121为椭圆形，虽然A子区域与C子区域内的光栅单元121的形态相同，但是两者并不相邻，而两者的光栅单元121的形态和与自身相邻的子区域的光栅单元121的形态不同。通过设计光栅单元121的具体形态，可以设计每个光栅单元121的基础光栅矢量对应衍射能级，从而设计合理的主路径和补偿路径。
值得说明的是，本申请实施例中光栅单元121的具体形态不做限制，具体可以为闪耀、倾斜、菱形、二元(binary)或者柱状(pillar)等光栅形态。
图12为本申请实施例中二维光栅的另一种结构示意图，请参考图12，上述二维光栅120还可以包括至少两个子区域，相邻子区域的第一距离Pm不同，相邻子区域的第二距离Pn不同。该实施例中的子区域是根据子区域的光栅单元121之间的距离不同来划分的，该方案中，可以提供第一光栅矢量
Figure PCTCN2022093392-appb-000124
和第二光栅矢量
Figure PCTCN2022093392-appb-000125
的多种可能，也就可以形成更多可能的合光栅矢量，进而可以形成多种光栅路径的组合，以使得较多的光线从出光区域140射出，增大视场角。
请继续参考图12，具体的，可以使二维光栅120包括两个子区域，分别为第一子区域150和第二子区域160，上述第二子区域160和第一子区域150沿第三方向y依次排布。入光区域130和出光区域140位于第一子区域150，第二子区域160位于出光区域140远离入光区域130的一侧，第一子区域150的第一距离Pm大于第二子区域160的第一距离Pm，第一子区域150的第二距离Pn大于第二子区域160的第二距离Pn，也就是说，第二子区域160的光栅周期小于第一子区域150的光栅周期。该方案可以减少光导100中的光线能量的损失，提高光导100传输光线的效率。
结合图2，当光线从入光区域130进入到光导100之后，在光导100内传输扩光之后，从出光区域140射出。但是，在出光区域140远离入光区域130的一侧还存在一些漏光，也就是第二子区域160中存在一部分漏光。该漏光指的是无法进入到人眼的光线。图12所示的实施例中，第二子区域160的光栅单元121的光栅周期较小，则形成的光栅矢量可以将传输到第二子区域160的光线回传到第一子区域150，例如入光区域130与出光区域140之间，然后可以再次利用光栅单元121传输从出光区域140射出，从而可以减少光导100中的光线能量的损失，提高光导100传输光线的效率。
具体的实施例中，上述第一子区域150的第一距离Pm是第二子区域160的第一距离 Pm的T倍，第一子区域150的第二距离Pn是第二子区域160的第二距离Pn的T倍，其中，T是至少为2的正整数。此外，上述第一子区域150内的各个光栅单元121之间的第一距离Pm可以相等，也可以不等，第二距离Pn可以相等，也可以不等。同样，第二子区域160内的各个光栅单元121之间的第一距离Pm可以相等，也可以不等，第二距离Pn可以相等，也可以不等。也就是说，上述第一子区域150内可以划分子区域，第二子区域160内也可以划分子区域，本申请不做限制。
当然，在其它的实施例中，如图1所示的实施例中，上述二维光栅120的第一距离Pm均相等，第二距离Pn也均相等，从而便于加工和制备光导100的二维光栅120。
具体设置上述第一距离Pm和第二距离Pn时，第一距离Pm的取值位于100nm至1000nm之间，第二距离Pn的取值位于100nm至1000nm之间。进一步的上述第一距离Pm的取值位于200nm至600nm之间，具体可以取300nm、400nm、430.5nm或者600nm等数值，第二距离Pn的取值位于200nm至600nm之间，具体可以取250nm、300nm、400nm、442.5nm、500nm、550nm或者600nm等数值。本申请不做限制。
本申请还提供了一种近眼显示装置，图13为本申请实施例中近眼显示装置的一种结构示意图，如图13所示，本申请实施例中的近眼显示装置包括上述任一实施例中的光导100，还包括壳体200和光机300，其中，光机300和光导100设置于上述壳体200。具体的，上述光机300用于生成光线，并将光线射至光导100的入光区域130，光导100在将上述光线扩光后射出，从而被人眼接收，使得用户能够获取画面01。具体的，上述光线可以为画面01的光线，可以包括红光、绿光和蓝光，利用本申请技术方案中的光导100，光导100采用一个导光板110就可以将上述三个颜色的光线的画面01以较大的视场角射出，从而简化近眼显示装置的结构，提高近眼显示装置的视场角，提升用户使用体验。
具体的实施例中，上述近眼显示装置可以为增强实现(augmented reality，AR)眼镜、或虚拟实现(virtual reality，VR)眼镜等，具体此处不做限定。
请继续参考图13，本申请实施例中的近眼显示装置的壳体200可以包括镜腿210(或者绑带)以及镜框220等结构，镜腿210和镜框220可以是任意合理形态外观排布。
请继续参考图13，具体的实施例中，近眼显示装置中的光机300包括激光器310和扫描器320，其中，激光器310发射出光线，扫描器320用于扫描上述激光器310发出的光线，并将该光线射向光导100。本实施例中，以激光器310和扫描器320组成的激光扫描系统作为投影光机300，具有对比度高、体积小、功耗低等优点。可以理解的是，在实际应用中，光机300还可以为其他系统，例如：硅基液晶(Liquid Crystal on Silicon，LCOS)光机300或者数字处理(Digital Light Processing，DLP)光机300等，具体此处不做限定。
此外，上述图13主要将光机300放置在镜框220上。图14为本申请实施例中近眼显示装置的另一种结构示意图，请参阅图14，但在实际应用中，光机300还可以设置在镜腿210上，本申请对于光机300设置的位置不做限定，只需合理布局光机300与光导100的位置即可，使光导100的入光区域130与光机300的出光区域140相对，使光导100的出光区域140与人眼所在的区域相对即可，此处不进行赘述。
显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的精神和范围。这样，倘若本申请的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。

Claims (16)

  1. 一种光导，其特征在于，包括导光板和设置于所述导光板表面的二维光栅，所述二维光栅包括多个光栅单元，所述多个光栅单元沿第一方向间隔第一距离排布，沿第二方向间隔第二距离排布，所述第一方向与所述第二方向相交；
    所述二维光栅包括沿第三方向排布的出光区域和入光区域，第四方向垂直于所述第三方向；所述第一方向、所述第二方向、所述第三方向和所述第四方向位于同一平面且任意两个方向不重合；
    所述光栅单元用于将一束入射光线衍射成至少三束出射光线。
  2. 如权利要求1所述的光导，其特征在于，所述第一方向和所述第二方向相对于所述第三方向对称。
  3. 如权利要求1或2所述的光导，其特征在于，所述二维光栅包括至少两个子区域，相邻所述子区域的所述光栅单元的形态不同。
  4. 如权利要求1～3任一项所述的光导，其特征在于，所述二维光栅的多个所述光栅单元形态相同。
  5. 如权利要求1～4任一项所述的光导，其特征在于，所述二维光栅包括至少两个子区域，相邻所述子区域的所述第一距离不同，相邻所述子区域的所述第二距离不同。
  6. 如权利要求5所述的光导，其特征在于，所述二维光栅包括第一子区域和第二子区域，所述入光区域和所述出光区域位于所述第一子区域，所述第二子区域位于所述出光区域远离所述入光区域的一侧，所述第一子区域的第一距离大于所述第二子区域的第一距离，所述第一子区域的第二距离大于所述第二子区域的第二距离。
  7. 如权利要求1～6任一项所述的光导，其特征在于，所述第一距离位于200nm至600nm之间，所述第二距离位于200nm至600nm之间。
  8. 如权利要求1～7任一项所述的光导，其特征在于，所述第一方向与所述第四方向的锐角夹角位于10°至80°之间，所述第二方向与所述第四方向的锐角夹角位于10°至80°之间。
  9. 如权利要求1～8任一项所述的光导，其特征在于，所述光栅单元生成第一光栅矢量和第二光栅矢量，以及多个合光栅矢量，所述第一光栅矢量垂直于所述第一方向，所述第二光栅矢量垂直于所述第二方向，所述合光栅失量为衍射级次M1的所述第一光栅矢量和衍射级次M2的所述第二光栅矢量的矢量和；其中，M1和M2为整数；所述入光区域的光栅单元接收光线，所述光线在所述导光板内经所述光栅单元的扩光之后，从所述出光区域的光栅单元射出；所述光线射至所述光栅单元之后，受所述第一光栅矢量、所述第二光栅矢量和所述合光栅矢量的作用下传输，所述光线传输过程中受到的光栅矢量的矢量和为零。
  10. 如权利要求9所述的光导，其特征在于，所述衍射级次M1包括-3、-2、-1、0、1、2和3；所述衍射级次M2包括-3、-2、-1、0、1、2和3。
  11. 如权利要求1～10任一项所述的光导，其特征在于，所述光导传输的画面视场角至少为60°。
  12. 一种近眼显示装置，其特征在于，包括壳体、光机，以及如权利要求1～11任一项所述的光导，其中，所述光机和所述光导设置于所述壳体，所述光机生成光线并射至所述光导的所述入光区域。
  13. 如权利要求12所述的近眼显示装置，其特征在于，包括虚拟现实眼镜或者增强现实眼镜。
  14. 如权利要求12或13所述的近眼显示装置，其特征在于，所述光机包括激光器、扫描器和控制器，所述扫描器用于扫描所述激光器发出的入射光线并发送给所述光导。
  15. 如权利要求12～14任一项所述的近眼显示装置，其特征在于，所述光机包括硅基液晶LCOS光机或数字光处理光机。
  16. 如权利要求12～15任一项所述的近眼显示装置，其特征在于，所述光机生成的光线包括红光、绿光和蓝光。
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