CN116430509A - Optical waveguide structure and AR equipment - Google Patents
Optical waveguide structure and AR equipment Download PDFInfo
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- CN116430509A CN116430509A CN202310458329.1A CN202310458329A CN116430509A CN 116430509 A CN116430509 A CN 116430509A CN 202310458329 A CN202310458329 A CN 202310458329A CN 116430509 A CN116430509 A CN 116430509A
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- 230000003287 optical effect Effects 0.000 title claims abstract description 64
- 210000001747 pupil Anatomy 0.000 claims abstract description 181
- 239000000758 substrate Substances 0.000 claims abstract description 27
- 230000005540 biological transmission Effects 0.000 claims abstract description 23
- 230000000903 blocking effect Effects 0.000 claims description 12
- 230000004424 eye movement Effects 0.000 abstract description 6
- 238000010586 diagram Methods 0.000 description 12
- 230000000694 effects Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 3
- 230000003190 augmentative effect Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 1
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- 230000031700 light absorption Effects 0.000 description 1
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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
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/0101—Head-up displays characterised by optical features
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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
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
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Abstract
The application discloses an optical waveguide structure and AR equipment, which relate to the technical field of optical display, and the optical waveguide structure comprises a substrate, wherein an entrance pupil grating unit and an exit pupil grating unit are arranged on the substrate along a first direction; a first path of turning components and a second path of turning components are symmetrically arranged along the first direction, the first path of turning components comprise a first turning grating and a second turning grating, input image light is diffracted into first transmission light and second transmission light through an entrance pupil grating unit, and the first transmission light is expanded and coupled out through the first turning grating, the second turning grating and an exit pupil grating unit to form first output light; the second transmission light is expanded through the third turning grating, the fourth turning grating and the exit pupil grating unit and coupled out to form second output light. The optical waveguide structure and the AR device can form two paths of output images at the exit pupil by utilizing the plurality of turning gratings, so that the eye movement range of the optical waveguide is enlarged.
Description
Technical Field
The application relates to the technical field of optical display, in particular to an optical waveguide structure and AR equipment.
Background
The augmented reality (Augmented Reality, AR) technology is a new technology for integrating real world information and virtual world information in a seamless mode, and is characterized in that entity information which is difficult to experience in a certain time space range of a real world originally is simulated and simulated through scientific technologies such as a computer and then superimposed, virtual information is applied to the real world and perceived by human senses, so that sense experience exceeding reality is achieved, and a real environment and a virtual object are superimposed on the same picture or space in real time and exist simultaneously. AR display systems typically include a micro projector and an optical display screen through which pixels on the micro display are projected into the human eye, while the user can see the real world through the optical display screen. The micro projector provides virtual content to the device and the optical display screen is typically a transparent optical component.
The optical waveguide structure is one implementation path of the optical display screen. When the refractive index of the transmission medium is greater than that of the surrounding medium and the incident angle in the waveguide is greater than the critical angle for total reflection, light can be transmitted without leakage in the waveguide, and total reflection occurs. After the light from the projector is coupled into the waveguide, the light continues to propagate the image within the waveguide without loss until it is coupled out by a subsequent structure. For AR display, the eye movement range of the optical waveguide is very important, and it is required to be able to adapt to users with different interpupillary distances, and the interpupillary distance ranges are different from 51 mm to 77 mm depending on age, sex and the like, and the eye movement range of the two eyes for observing 1 exit pupil display image needs to satisfy the visual range larger than the interpupillary distance; or the moving sight line for single-eye observation also requires a large eye movement range of the pupil display image, so that partial image incomplete observation can not be caused when the movement is realized. However, the eye movement range of prior art optical waveguides is typically relatively small, making the user experience poor.
Disclosure of Invention
An object of the present invention is to provide an optical waveguide structure and an AR device capable of forming two output images at an exit pupil using a plurality of turning gratings, thereby increasing an eye movement range of the optical waveguide.
In one aspect, an embodiment of the present application provides an optical waveguide structure, including a substrate, on which an entrance pupil grating unit and an exit pupil grating unit are disposed along a first direction; a first path of turning components and a second path of turning components are symmetrically arranged along the first direction, the first path of turning components comprise a first turning grating and a second turning grating, the second path of turning components comprise a third turning grating and a fourth turning grating, input image light is diffracted into first transmission light and second transmission light through an entrance pupil grating unit, and the first transmission light is expanded and coupled out through the first turning grating, the second turning grating and an exit pupil grating unit to form first output light; the second transmission light is expanded through the third turning grating, the fourth turning grating and the exit pupil grating unit and coupled to form second output light.
As an implementation manner, the first turning grating and the third turning grating are disposed on two opposite sides of the substrate, and projections of the first turning grating and the third turning grating on the substrate overlap.
As an implementation manner, an included angle between the grating direction of the first turning grating and the second direction is θ1, and an included angle between the grating direction of the third turning grating and the second direction is θ2, where θ1 and θ2 are respectively located at two sides of the second direction and are both smaller than 90 °, and where the second direction is perpendicular to the first direction.
As an embodiment, the exit pupil grating unit is an integral structure; or the exit pupil grating unit comprises a first exit pupil grating positioned at the light exit side of the second turning grating and a second exit pupil grating positioned at the light exit side of the fourth turning grating, and the grating directions of the first exit pupil grating and the second exit pupil grating are the same or different.
As an embodiment, the first exit pupil grating and the second exit pupil grating are arranged at intervals along the second direction, and the distance between the first exit pupil grating and the second exit pupil grating is greater than the length of the entrance pupil grating unit along the second direction, wherein the first direction is perpendicular to the second direction.
As an embodiment, the entrance pupil grating unit and the exit pupil grating unit are disposed on two opposite sides of the first rotating refractive grating along the second direction; or the entrance pupil grating unit and the exit pupil grating unit are arranged on the same side of the first rotating refractive grating along the second direction.
As an implementation manner, a light blocking member is arranged between the first turning grating and the exit pupil grating unit and between the third turning grating and the exit pupil grating unit; or a light blocking member is arranged between the entrance pupil grating unit and the exit pupil grating unit.
As an embodiment, the grating direction of the entrance pupil grating unit is perpendicular to the first direction.
As an implementation manner, the grating vector directions of the entrance pupil grating unit, the first turning grating, the second turning grating and the exit pupil grating unit form a first closed loop; the grating vector directions of the entrance pupil grating unit, the third turning grating, the fourth turning grating and the exit pupil grating unit form a second closed loop.
In another aspect, an embodiment of the present application provides an AR device, including a frame and one or two optical waveguide structures disposed on the frame, where a first output light and a second output light of one optical waveguide structure respectively form an input dual-purpose output image, or output light of two optical waveguide structures respectively form an input dual-purpose output image.
The beneficial effects of the embodiment of the application include:
the optical waveguide structure comprises a substrate, wherein an entrance pupil grating unit and an exit pupil grating unit are arranged on the substrate along a first direction; a first path of turning components and a second path of turning components are symmetrically arranged along the first direction, the first path of turning components comprise a first turning grating and a second turning grating, the second path of turning components comprise a third turning grating and a fourth turning grating, input image light is diffracted into first transmission light and second transmission light through an entrance pupil grating unit, and the first transmission light is expanded and coupled out through the first turning grating, the second turning grating and an exit pupil grating unit to form first output light; the second transmission light expands and couples through the third turning grating, the fourth turning grating and the exit pupil grating unit to form second output light, wherein the first output light forms a first output image and an eyebox1, the second output light forms a second output image and an eyebox2, and an area where the first output light and the second output light overlap forms an eyebox3, so that the eyebox formed by the first output light and the second output light is equal to eyebox1+eyebox2+eyebox3, thereby enlarging the eyebox of the optical waveguide, enlarging the visual range, and improving the user experience.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of an optical waveguide structure according to an embodiment of the present application;
FIG. 2 is a second schematic structural diagram of an optical waveguide structure according to an embodiment of the present disclosure;
fig. 3 is a schematic diagram of a grating vector of an optical waveguide structure according to an embodiment of the present application;
fig. 4 is a schematic diagram of an optical waveguide structure according to an embodiment of the present disclosure;
fig. 5 is a schematic structural diagram of another optical waveguide structure according to an embodiment of the present disclosure;
FIG. 6 is a schematic diagram of a grating vector of another optical waveguide structure according to an embodiment of the present disclosure;
fig. 7 is a schematic structural diagram of still another optical waveguide structure according to an embodiment of the present disclosure;
FIG. 8 is a schematic diagram of a grating vector of another optical waveguide structure according to an embodiment of the present disclosure;
fig. 9 is a schematic structural view of still another optical waveguide structure according to an embodiment of the present application;
fig. 10 is a schematic structural diagram of another optical waveguide structure according to an embodiment of the present application.
Icon: 10-an optical waveguide structure; 11-a substrate; 12-an entrance pupil grating unit; 13-an exit pupil grating unit; 131-a first exit pupil grating; 132-a second exit pupil grating; 14-a first path turning component; 141-a first turning grating; 142-a second turning grating; 15-a second path turning component; 151-a third turning grating; 152-fourth turning grating; 16-light barrier.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, which are generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present application, as provided in the accompanying drawings, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
In the description of the present application, it should be noted that, the terms "center," "vertical," "horizontal," "inner," "outer," and the like indicate an azimuth or a positional relationship based on that shown in the drawings, or an azimuth or a positional relationship that a product of the application is conventionally put in use, merely for convenience of describing the present application and simplifying the description, and do not indicate or imply that the apparatus or element to be referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.
The application provides an optical waveguide structure 10, as shown in fig. 1, 2, 3 and 4, comprising a substrate 11, wherein an entrance pupil grating unit 12 and an exit pupil grating unit 13 are arranged on the substrate 11 along a first direction; a first path of turning components 14 and a second path of turning components 15 are symmetrically arranged along the first direction, the first path of turning components 14 comprises a first turning grating 141 and a second turning grating 142, the second path of turning components 15 comprises a third turning grating 151 and a fourth turning grating 152, input image light is diffracted into first transmission light and second transmission light through the entrance pupil grating unit 12, and the first transmission light is expanded and coupled out through the first turning grating 141, the second turning grating 142 and the exit pupil grating unit 13 to form first output light; the second transmitted light is expanded and coupled through the third turning grating 151, the fourth turning grating 152, and the exit pupil grating unit 13 to form a second output light.
When the optical waveguide structure 10 works, as shown in fig. 1, an input image light INO is incident to an entrance pupil grating unit 12, under the diffraction effect of the entrance pupil grating unit 12, a positive first-order light formed by diffraction enters a substrate 11, the diffracted light is totally reflected to a first turning refraction grating 141 and a third turning grating 151 as a first transmission light and a second transmission light, the first transmission light is totally reflected to a second turning grating 142 through the diffracted light of the first turning refraction grating 141, and then is totally reflected to an exit pupil grating unit 13 through the diffracted light of the second turning grating 142, and finally, a first output light is output at the exit pupil grating unit 13, and the first output light enters a human eye at an observation distance to form an eyebox1; the second transmission light is totally reflected to the fourth turning grating 152 through the diffraction light of the third turning grating 151, and then is totally reflected to the exit pupil grating unit 13 through the diffraction light of the fourth turning grating 152, and finally, the second output light is output at the exit pupil grating unit 13, and enters the human eye at the observation distance to form eyebox2; the second turning grating 142 and the fourth turning grating 152 have a certain width, and exit light is provided in the width direction of the entire second turning grating 142 and the fourth turning grating 152, so that light entering the exit pupil grating unit 13 has a certain width, so that the first output light and the second output light have overlapping regions, and the overlapping regions of the first output light and the second output light enter the human eye at the same viewing distance to form eyebox3, so that eyebox=eyebox 1+eyebox2+eyebox3 at the exit pupil grating unit 13 is obtained, thereby increasing the visible range of the image.
Specifically, as shown IN fig. 4, the input image light IN0 generated by the micro projector includes a propagation light ray within a certain angle range, the angle range is a projection view angle θ of the image, the length of the exit pupil grating unit 13 along the second direction is L, the distance eeeyrelief from the human eye to the substrate 11 is D, the first transmission light enters the human eye at a first output light with an exit view angle FOV1 at one side of the exit pupil grating unit 13 to form eebox 1, the second transmission light enters the human eye at a second output light with an exit view angle FOV2 at the other side of the exit pupil grating unit 13 to form eebox 2; forming an eyebox3 in the overlapping area of the FOV1 and FOV2 light rays, so that the field angle of all the light rays emitted by the whole exit pupil grating unit 13 is FOV3, and forming an integral eyebox at the human eye as eyebox1+eyebox2+eyebox3 with a length of l; where FOV 1=fov 2=fov 3=θ, then l=l-2×d×tan (θ/2).
The optical waveguide structure 10 provided in the embodiment of the present application is applied to an AR device, and forms two paths of output light at the exit pupil grating unit 13 by using a plurality of turning gratings, so that the eyebox is increased, and when the optical waveguide structure is applied to binocular observation, the eyebox of an exit pupil display image is larger than the requirement of the visible range of the inter-pupil distance; when the method is applied to monocular, the requirement of monocular observation on moving vision can be met; meanwhile, the brightness uniformity of an output image can be improved by superposing two paths of output light at infinity, and the experience effect of the AR equipment is improved.
Alternatively, as shown in fig. 1, the first turning grating 141 and the third turning grating 151 are disposed on opposite sides of the substrate 11, and the projections of the first turning grating 141 and the third turning grating 151 on the substrate 11 overlap.
The specific dimensions and arrangement positions of the first turning grating 141, the second turning grating 142, the third turning grating 151 and the fourth turning grating 152 are not limited in this embodiment, as long as the first and second conducted lights can be diffracted and output, and as shown in fig. 2, the entrance pupil grating unit 12 is illustratively arranged on the central axis of the substrate 11 along the second direction and is arranged at an upper position along the first direction, the first turning grating 141 and the third turning grating 151 are located under the entrance pupil grating unit 12, the dimensions of the first turning grating 141 and the third turning grating 151 are the same, and the length along the second direction is 1.5-3 times the length of the entrance pupil grating unit 12, and the width along the first direction is 1-3 times the width of the entrance pupil grating unit 12; the length of the second turning grating 142 is 3-8 times of the length of the first turning grating 141, and the width of the second turning grating 142 is 1.5-3 times of the length of the first turning grating 141; the second turning grating 142 and the fourth turning grating 152 are axially symmetrical; the length of the exit pupil grating unit 13 is 5-15 times the length of the entrance pupil grating unit 12, and the width is 0.5-0.8 times the length thereof.
The arrangement positions of the entrance pupil grating unit 12, the exit pupil grating unit 13, the second turning grating 142 and the fourth turning grating 152 are not specifically limited, and may be disposed on the same surface of the substrate 11 as the first turning grating 141, or may be disposed on the same surface of the substrate 11 as the third turning grating 151, and the entrance pupil grating unit 12, the exit pupil grating unit 13, the second turning grating 142 and the fourth turning grating 152 may be disposed on the same side or on different sides.
In an implementation manner of this embodiment, as shown in fig. 1 and fig. 2, an included angle between a grating direction of the first turning grating 141 and the first direction is θ1, and an included angle between a grating direction of the third turning grating 151 and the first direction is θ2, where θ1 and θ2 are respectively located at two sides of the second direction and are both smaller than 90 °.
θ1 and θ2 are located at two sides of the first direction, and are both smaller than 90 ° such that the first turning grating 141 and the third turning grating 151 diffract the diffracted light of the entrance pupil grating unit 12 in different directions, forming first and second conducted light.
Alternatively, as shown in fig. 2 and 5, the exit pupil grating unit 13 is a unitary structure; alternatively, as shown in fig. 7, 9 and 10, the exit pupil grating unit 13 includes a first exit pupil grating 131 located on the light exit side of the second turning grating 142 and a second exit pupil grating 132 located on the light exit side of the fourth turning grating 152, and the grating directions of the first exit pupil grating 131 and the second exit pupil grating 132 are the same or different.
When the grating directions of the exit pupil grating units 13 corresponding to the second turning grating 142 and the fourth turning grating 152 are the same, the exit pupil grating units 13 may be set as an integral structure; when the grating directions of the exit pupil grating units 13 corresponding to the second turning grating 142 and the fourth turning grating 152 are different, the exit pupil grating unit 13 includes a first exit pupil grating 131 located at the light exit side of the second turning grating 142 and a second exit pupil grating 132 located at the light exit side of the fourth turning grating 152.
In one implementation manner of this embodiment, as shown in fig. 9 and fig. 10, the first exit pupil grating 131 and the second exit pupil grating 132 are disposed at intervals along the second direction, and the distance between the first exit pupil grating 131 and the second exit pupil grating 132 is greater than the length of the entrance pupil grating unit 12 along the second direction, where the first direction is perpendicular to the second direction. Such arrangement avoids light rays of the first turning refractive grating 141 and the third turning refractive grating 151 from entering the exit pupil grating unit 13, eliminates influence of light rays of the first turning refractive grating 141 and the third turning refractive grating 151 on the exit pupil grating unit 13, and can also enable the optical waveguide structure 10 of the present application to be a binocular integrated waveguide structure, and the first exit pupil grating 131 and the second exit pupil grating 132 respectively correspond to one of the binocular.
When the first exit pupil grating 131 and the second exit pupil grating 132 are disposed at intervals along the second direction, the entrance pupil grating unit 12 and the exit pupil grating unit 13 may be disposed on the same side of the line connecting the first path turning component 14 and the second path turning component 15, as shown in fig. 9; the entrance pupil grating unit 12 and the exit pupil grating unit 13 may also be arranged on different sides of the connection of the first path turning component 14 and the second path turning component 15, as shown in fig. 10.
Alternatively, as shown in fig. 2, 7 and 10, the entrance pupil grating unit 12 and the exit pupil grating unit 13 are disposed on opposite sides of the first turning grating 141 in the second direction; alternatively, as shown in fig. 5 and 9, the entrance pupil grating unit 12 and the exit pupil grating unit 13 are disposed on the same side of the first turning grating 141 in the second direction.
When the entrance pupil grating unit 12 and the exit pupil grating unit 13 are disposed on two opposite sides of the first turning grating 141 along the second direction, the optical path is relatively regular.
Since the entrance pupil grating unit 12 has two positive and negative diffraction orders, when the entrance pupil grating unit 12 and the exit pupil grating unit 13 are disposed on the same side of the first turning grating 141 along the second direction, the entrance pupil grating unit 12 is between the exit pupil grating unit 13 and the first turning grating 141, so that the distance between the first turning grating 141 and the exit pupil grating unit 13 is increased, and the size of the entrance pupil grating unit 12 can be designed so as not to obstruct the optical path between the first turning grating 141 and the exit pupil grating unit 13.
In one implementation manner of the embodiment of the present application, as shown in fig. 2 and 7, a light blocking member 16 is disposed between the first turning grating 141 and the exit pupil grating unit 13, and between the third turning grating 151 and the exit pupil grating unit 13; alternatively, a light blocking member 16 is provided between the entrance pupil grating unit 12 and the exit pupil grating unit 13.
When the entrance pupil grating unit 12 and the exit pupil grating unit 13 are disposed on two opposite sides of the first turning grating 141 along the second direction, a light blocking member 16 is disposed between the first turning grating 141 and the exit pupil grating unit 13, for blocking the negative first-order diffracted light of the first turning grating 141 from directly entering the exit pupil grating unit 13, forming stray light, and affecting the display effect of the optical waveguide structure 10. Similarly, a light blocking member 16 is disposed between the third turning grating 151 and the exit pupil grating unit 13, and is used for blocking the negative-order diffracted light of the third turning grating 151 from entering the exit pupil grating unit 13, so as to form stray light. It is understood that the two light blocking members 16 may be of a unitary structure due to the overlapping projections of the first turning refractive grating 141 and the third turning unit on the substrate 11.
When the entrance pupil grating unit 12 and the exit pupil grating unit 13 are disposed on the same side of the first turning grating 141 along the second direction, the light diffracted by the entrance pupil grating unit 12 is prevented from directly entering the exit pupil grating unit 13, so as to form stray light.
Specifically, the specific structure of the light blocking member 16 is not limited in the embodiment of the present application, as long as it can block the continued propagation of light, and may be exemplified by cutting the texture on the surface of the substrate 11; the substrate 11 can also be a hollowed-out part, and the cutting edge of the hollowed-out part is provided with a light absorption layer; or may be a light absorbing layer attached to the surface of the substrate 11.
Alternatively, the grating direction of the entrance pupil grating unit 12 is perpendicular to the first direction.
The grating direction of the entrance pupil grating unit 12 is perpendicular to the first direction, and the grating directions of the other grating units are not specifically limited in this embodiment, and as shown in fig. 2, for example, the included angle between the grating direction of the first turning refractive grating 141 and the positive direction of the second direction is 30-75 °, and the grating direction of the second turning refractive grating 142 is the same as the grating direction of the first turning refractive grating 141; the included angle between the third turning grating 151 and the positive direction of the second direction is 105-150 degrees, and the grating direction of the fourth turning grating 152 is the same as that of the third turning grating 151; the grating direction of the exit pupil grating unit 13 is the same as the grating direction of the entrance pupil grating unit 12. In addition, the grating has a grating vector, the vector direction of the grating is perpendicular to the grating direction of the corresponding grating, fig. 3 is a K-space vector diagram of the propagation of the positive first order diffracted light in the optical waveguide structure 10 of fig. 2, where the vector direction of the positive first order diffracted light entering the substrate 11 by the entrance pupil grating unit 12 is V11, the light propagates down to the first turning refractive grating 141 along the vector direction V11, the light diffracted by the first turning refractive grating 141 enters the second turning refractive grating 142 along V21, the light diffracted by the second turning refractive grating 142 enters the exit pupil grating unit 13 along V31, and finally exits at the exit pupil grating unit 13 in the V42 direction, and the grating vector direction of the first guided light forms a closed loop, that is, the wave vector sum of the light is v11+v21+v31+v41=0. Similarly, the grating vector direction of the second conducted light forms a closed loop, i.e., the wave vector sum v12+v22+v32+v42=0.
In fig. 3, BND1 represents a first boundary for satisfying the Total Internal Reflection (TIR) criterion in the waveguide plate SUB 1. BND2 represents the second boundary of the largest wave vector in waveguide plate SUB 1. The maximum wave vector may be determined by the refractive index of the waveguide plate. Only when the wave vector of the light is in the ZONE1 between the first and the second boundary BND1, 2, the light can be waveguided in the plate. If the wave vector of the light is outside the ZONE1, the light may leak out of the waveguide plate or not propagate at all.
As shown in fig. 5, the grating direction of the entrance pupil grating unit 12 is perpendicular to the first direction, the included angle between the grating direction of the first turning grating 141 and the positive direction of the second direction is 30-60 °, and the included angle between the grating direction of the second turning grating 142 and the positive direction of the second direction is 110-150 °; the included angle between the grating direction of the third turning grating 151 and the positive direction of the second direction is 120-160 degrees, and the included angle between the grating direction of the fourth turning grating 152 and the positive direction of the second direction is 30-70 degrees; the grating direction of the exit pupil grating unit 13 is the same as the grating direction of the entrance pupil grating unit 12. Fig. 6 is a K space vector diagram of the propagation of the positive first order diffracted light in the optical waveguide structure 10 of fig. 5, where the vector direction of the positive first order diffracted light entering the substrate 11 by the entrance pupil grating unit 12 is V11, the light propagates down to the first turning grating 141 along the vector direction V11, the light diffracted by the first turning grating 141 enters the second turning grating 142 along V21, the light diffracted by the second turning grating 142 enters the exit pupil grating unit 13 along V31, and finally exits at the exit pupil grating unit 13 in the V42 direction, and the grating vector direction of the first conducted light forms a closed loop, i.e., the wave vector sum of the light is v11+v21+v31+v41=0. Similarly, the grating vector direction of the second conducted light forms a closed loop, i.e., the wave vector sum v12+v22+v32+v42=0.
As shown in fig. 7, the grating direction of the entrance pupil grating unit 12 is perpendicular to the first direction, the included angle between the grating direction of the first turning grating 141 and the positive direction of the second direction is 45 °, the included angle between the grating direction of the second turning grating 142 and the positive direction of the second direction is 67 °, and the included angle between the grating direction of the first exit pupil grating 131 and the positive direction of the second direction is 45 °; the included angle between the grating direction of the third turning grating 151 and the positive direction of the second direction is 135 degrees, and the included angle between the fourth turning grating 152 and the positive direction of the second direction is 113 degrees; the grating direction of the first exit pupil grating 131 is at an angle of 135 ° to the positive direction of the second direction. Fig. 8 is a K-space vector diagram of the propagation of the positive first order diffracted light in the optical waveguide structure 10 of fig. 7, where the grating vector direction of the first transmitted light forms a closed loop, i.e., the wave vector sum of the light rays is v11+v21+v31+v41=0. The grating vector direction of the second conducted light forms a closed loop, i.e. the wave vector sum v12+v22+v32+v42=0.
The above three embodiments are merely examples of the present application, and those skilled in the art may make specific adjustments according to the actual implementation.
In one implementation manner of the embodiment of the present application, as shown in fig. 3, 6 and 8, the grating vector directions of the entrance pupil grating unit 12, the first turning grating 141, the second turning grating 142 and the exit pupil grating unit 13 form a first closed loop; the grating vector directions of the entrance pupil grating unit 12, the third turning grating 151, the fourth turning grating 152, and the exit pupil grating unit 13 form a second closed loop.
The embodiment of the application also discloses an AR device, which includes a frame and one or two optical waveguide structures 10 set on the frame, where the first output light and the second output light of one optical waveguide structure 10 respectively form an input dual-purpose output image, or the output light of two optical waveguide structures 10 respectively form an input dual-purpose output image. The AR device includes the same structure and advantageous effects as the optical waveguide structure 10 in the foregoing embodiment. The specific structure and advantageous effects of the optical waveguide structure 10 have been described in detail in the foregoing embodiments, and are not described in detail herein.
The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the same, but rather, various modifications and variations may be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims (10)
1. The optical waveguide structure is characterized by comprising a substrate, wherein an entrance pupil grating unit and an exit pupil grating unit are arranged on the substrate along a first direction; a first path of turning components and a second path of turning components are symmetrically arranged along a first direction, the first path of turning components comprise a first turning grating and a second turning grating, the second path of turning components comprise a third turning grating and a fourth turning grating, input image light is diffracted into first conducted light and second conducted light through the entrance pupil grating unit, and the first conducted light is expanded and coupled out through the first turning grating, the second turning grating and the exit pupil grating unit to form first output light; the second transmission light is expanded and coupled out through the third turning grating, the fourth turning grating and the exit pupil grating unit to form second output light.
2. The optical waveguide structure of claim 1, wherein the first turning grating and the third turning grating are disposed on opposite sides of the substrate, and projections of the first turning grating and the third turning grating on the substrate overlap.
3. The optical waveguide structure according to claim 2, wherein an included angle between a grating direction of the first turning grating and a second direction is θ1, and an included angle between a grating direction of the third turning grating and the second direction is θ2, wherein θ1 and θ2 are located at two sides of the second direction, respectively, and are both smaller than 90 °, and wherein the second direction is perpendicular to the first direction.
4. The optical waveguide structure according to claim 1, wherein the exit pupil grating unit is a unitary structure; or the exit pupil grating unit comprises a first exit pupil grating positioned at the light exit side of the second turning grating and a second exit pupil grating positioned at the light exit side of the fourth turning grating, and the grating directions of the first exit pupil grating and the second exit pupil grating are the same or different.
5. The optical waveguide structure of claim 4, wherein the first exit pupil grating and the second exit pupil grating are spaced apart along a second direction, and a distance between the first exit pupil grating and the second exit pupil grating is greater than a length of the entrance pupil grating unit along the second direction, wherein the first direction is perpendicular to the second direction.
6. The optical waveguide structure according to claim 3, wherein the entrance pupil grating unit and the exit pupil grating unit are disposed on opposite sides of the first turning refractive grating in the second direction; or the entrance pupil grating unit and the exit pupil grating unit are arranged on the same side of the first turning grating along the second direction.
7. The optical waveguide structure according to claim 6, wherein a light blocking member is provided between the first turning grating and the exit pupil grating unit, and between the third turning grating and the exit pupil grating unit; or a light blocking member is arranged between the entrance pupil grating unit and the exit pupil grating unit.
8. The optical waveguide structure according to claim 1, wherein the grating direction of the entrance pupil grating unit is perpendicular to the first direction.
9. The optical waveguide structure according to claim 1, wherein the grating vector directions of the entrance pupil grating unit, the first turning grating, the second turning grating, and the exit pupil grating unit form a first closed loop; and the grating vector directions of the entrance pupil grating unit, the third turning grating, the fourth turning grating and the exit pupil grating unit form a second closed loop.
10. An AR device comprising a frame and one or two optical waveguide structures according to any one of claims 1-9 arranged on said frame, the first output light and the second output light of one of said optical waveguide structures forming an input dual-purpose output image, respectively, or the output light of both of said optical waveguide structures forming an input dual-purpose output image, respectively.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310458329.1A CN116430509A (en) | 2023-04-18 | 2023-04-18 | Optical waveguide structure and AR equipment |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310458329.1A CN116430509A (en) | 2023-04-18 | 2023-04-18 | Optical waveguide structure and AR equipment |
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| CN116430509A true CN116430509A (en) | 2023-07-14 |
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| CN202310458329.1A Pending CN116430509A (en) | 2023-04-18 | 2023-04-18 | Optical waveguide structure and AR equipment |
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