Optical conduit for eyewear device, eyewear device and method of operation and manufacture of optical conduit

Abstract

The light pipe of an augmented or virtual reality eyewear device (10) comprises an additional grating (110) arranged between an in-coupling grating (102) and an out-coupling grating (104). The additional grating (110) comprises grating areas (112, 112', 114, 114') having a common physical interface (116) and grating vectors of different directions. The grating vectors of the additional grating (110), the in-coupling grating (102) and the out-coupling grating (104) are linear combinations of two non-parallel and common base vectors, and the sum of the grating vectors of the in-coupling grating (102), the additional grating (110) and the out-coupling grating (104) is zero for each light path, respectively, which guides light from the in-coupling grating (102) via the additional grating (110) to the out-coupling grating (104) and allows the light to be out-coupled from the out-coupling grating (104).

Description

Technical Field

[0001] This invention relates to a light guide for an augmented or virtual reality glasses device, an augmented or virtual reality glasses device, and a method for operating and manufacturing the light guide. Background Technology

[0002] When using diffraction-based augmented reality (AR) or virtual reality (VR) glasses, light in the visible range is coupled into a light guide tube via an ingress diffraction grating, and after the light has been distributed inside the light guide tube, it is coupled out via an egress diffraction grating, allowing the user to see an image received by the first diffraction grating. In addition to digital representation, augmented reality glasses also allow the user to see their surroundings through the light guide tube.

[0003] An exit pupil expander (EPE) is used within the light guide between the input and output light to distribute the input light over a larger area before output. The rotation angle between the grating and grating period has also been adjusted to control the area and shape of the light guide. However, adding an EPE within the light guide results in a large surface area, as the light guide must efficiently guide all light to the output coupling area. The increased area also creates problems for the shape and design of the glasses and how the input and output light are positioned relative to each other. Therefore, improvements would be welcome. Summary of the Invention

[0004] This invention seeks to provide improvements to eyeglasses.

[0005] This invention is defined by the independent claims. Embodiments are defined in the dependent claims. Attached Figure Description

[0006] The following description, with reference to the accompanying drawings, illustrates exemplary embodiments of the present invention by way of example only, wherein...

[0007] Figure 1A IB shows examples of augmented reality glasses;

[0008] Figure 2 An example of a light guide tube for an augmented or virtual reality glasses device as seen from above;

[0009] Figure 3 An example of a light guide tube as seen from above is shown;

[0010] Figure 4 This shows another example of a light guide tube as seen from above;

[0011] Figure 5 This shows another example of a light guide tube as seen from above;

[0012] Figure 6 Another example of a light guide tube as seen from above is shown;

[0013] Figure 7 An example of a light guide tube is shown in perspective.

[0014] Figure 8 An example of a light guide tube with an additional grating guiding light region is shown;

[0015] Figure 9 An example is shown where the light guide tube includes multiple grating regions;

[0016] Figure 10 Showing something similar to Figure 9 The difference is that the input grating is physically separated from the additional grating and the output grating;

[0017] Figure 11 Showing something similar to Figure 9 and Figure 10 The difference is that the input and output gratings 104 are physically separated from the additional grating;

[0018] Figure 12 An example showing the propagation directions of two different wavelengths inside a light guide tube;

[0019] Figure 13 An example flowchart illustrating the operation method of the light guide tube in an augmented or virtual reality glasses device;

[0020] Figure 14 An example flowchart illustrating a method for manufacturing a light guide for an augmented or virtual reality glasses device. Detailed Implementation

[0021] The following embodiments are merely examples. Although the specification may refer to "one" embodiment in several places, this does not necessarily mean that each such reference is for the same embodiment or that the feature applies only to a single embodiment. Individual features of different embodiments may also be combined to provide other embodiments. Furthermore, the words "comprising" and "having" should be understood not to limit the described embodiments to including only those features already mentioned, and such embodiments may also include features / structures not specifically mentioned. All combinations of embodiments are considered possible if their combinations do not lead to structural or logical contradictions.

[0022] It should be noted that although the accompanying drawings illustrate various embodiments, they are simplified diagrams showing only some structural and / or functional entities. Connections shown in the drawings can refer to logical or physical connections. It will be apparent to those skilled in the art that the described apparatus may also include functions and structures other than those described in the drawings and text. It should be understood that details of some functions, structures, and signaling and / or control are irrelevant to the actual invention. Therefore, further discussion is unnecessary here.

[0023] In existing designs, the placement of the input and output gratings is subject to certain limitations, and in some cases, severe limitations. In this paper, an additional exit pupil expander (EPE), i.e., an additional grating, is placed within the light guide tube, such that the input light propagating inside the light guide tube is guided to the integrated EPE region to form a single EPE structure, which further alters the propagation direction. A portion of the light guided by the EPE can also directly reach the output grating. Using an additional EPE allows for greater freedom in adjusting the position of the input grating and / or controlling the total area covered by the grating and / or the total area of ​​the light guide tube.

[0024] Figure 1A Examples of AR (Augmented Reality) or VR (Virtual Reality) glasses 10 are shown in Figure 10. For example, glasses 10 can look like glasses, spectacles, or goggles. In one implementation, the glasses can be attached to a headgear (e.g., a cap, hat, or helmet). For example, the glasses can be a near-eye display, a head-mounted display, a wearable display, cinema glasses, or smart glasses.

[0025] exist Figure 1A In the glasses 10, there are light guide tubes 106 and image generation units 12. The image generation units 12 may have an image source 14 and an optical component arrangement 16. The image generation units 12 generate visible light for images (static or video). The visible light is coupled to the light guide tube 106 through the optical component arrangement 16 and a coupling diffraction grating 102 on the surface of the light guide tube 106.

[0026] In Figure 1B, the eyepiece comprises two parts, A and B, each for one eye 150, 152. The image generation unit 12 can guide the visible light of the image to an optical component arrangement 16, which can separate the light for the two parts A and B. Instead of beam splitting, the eyepiece can have two image generation units 12, each for one part A and one part B. Various possibilities exist for placing or fixing the image generation units 12 to the eyepiece, but these need not be discussed in more detail here.

[0027] The light guide 106 allows visible light to propagate from the coupled-in diffraction grating 102 to one or more first coupled-out diffraction gratings 100, 104 via total internal reflection. For example, the light guide 106 may be made of a transparent material such as glass, sapphire, and / or polymers. For example, the glass may comprise a family of high-refractive-index flint glasses. The refractive index of the light guide 106 may be from about 1.5 to about 2 or higher.

[0028] replace Figure 1AAs shown in IB, the enhanced or virtual image of glasses 10 can be applied to only a single eye, such that the light guide 106 or the coupling grating is only in front of said single eye.

[0029] Therefore, visible light is laterally guided within the light guide 106 based on vertical reflection, and one or both of the coupled diffraction gratings 100 and 104 couple the visible light out of the light guide 106 to direct the visible light to one or both of the user's eyes 150 and 152 for displaying an image. The coupled diffraction gratings 100 and 104 serve as optical combiners in the augmented reality glasses. The user can see the environment through the light guide 10 and the image diffracted from the first diffraction grating 100 and the second diffraction grating 104.

[0030] exist Figure 1A In the exemplary embodiment shown, the glasses have a light guide 10 for two eyes 150, 152 and an image generation unit 12.

[0031] In one embodiment, the glasses may have a light guide 10 and an image generation unit 12 for each eye 150, 152.

[0032] The input diffraction grating 100 and the output diffraction grating 104 may be on the common side of the light guide 106. In one embodiment, at least one of the diffraction gratings 100 to 104 may be on the side of the light guide 106 opposite to at least one of them.

[0033] Figure 2 An example of a light guide 106 of an augmented or virtual reality glasses device 10, as seen from above, is shown. The light guide 106 includes an additional grating 110 disposed between an input grating 102 and an output grating 104. The additional grating 110 may be a single integrated grating. This means that the additional grating 110 is not formed from separate grating sheets spaced apart from each other.

[0034] The additional grating 110 includes multiple grating regions 112, 112', 114, 114', with at least two grating regions 112, 112', 114, 114' having a common physical interface 116. Different grating regions 112, 112', 114, 114' also have grating vectors pointing in different directions. In one embodiment, the grating vectors are not parallel; that is, they do not point in a common direction, and they do not point in opposite directions.

[0035] Each of the grating vectors in the additional grating 110, the input grating 102, and the output grating 104 is a linear combination of two non-parallel, common basis vectors. The common basis vectors are not parallel to each other. The common basis vectors are common to each individual additional grating 112, 112', 114, 114', input grating 102, and output grating 104. The sum of the grating vectors of the input grating 102, additional grating 110, and output grating 104 is zero for each optical path, which guides light from the input grating 102 via the additional grating 110 to the output grating 104 and allows light to couple out from the output grating 104.

[0036] In one implementation, the angle between the directions of the basis vectors is at least one of the following: 45°, 60°, and 90°. In one implementation, the value of the sine function of the angle or the square of the value of the sine function of the angle may have a rational value. A rational number is represented as the quotient or fraction of two integers, p / q, where p and q are integers.

[0037] In one implementation, the first of the two basis vectors may have a different magnitude than the second of the two basis vectors.

[0038] In one implementation, the linear combination of basis vectors is formed by multiplying at least one of the basis vectors by a constant, which can be an integer, and then summing the basis vectors together. The linear combination of the first basis vector a and the second basis vector b will then be kl*a + k2*b, where the coefficients kl and k2 can be integers: ... -2, -1, 0, 1, 2, ... . In one implementation, the coefficients can be rational numbers or real numbers.

[0039] In one embodiment, the additional grating 110 may include an array of grating regions 112, 112', 114, 114' arranged continuously in the light propagation direction between the input grating 102 and the output grating 104. In one embodiment, light may at least partially return to the grating regions after diffracting to one or more grating regions or gratings. The grating regions 112, 112', 114, 114' may be turning points in light propagation, with light diffracting at each grating region 112, 112', 114, 114' such that the propagation of the diffracted light has a directional component in the transverse direction of the light guide 106. The array of grating regions 112, 112', 114, 114' can be considered as an ordered arrangement that cooperates to achieve the desired result.

[0040] The first grating regions 112, 112' of the array receive light from the coupled grating 102, and the last grating regions 114, 114' of the array forward the light to the coupled grating 104. In one embodiment, any grating region 112, 112', 114, 114' in the array, other than the last grating regions 114, 114', can transmit at least a portion of the light received from the previous grating to the next grating or grating region. The previous grating can be the coupled grating 102 or a grating region. When light is forwarded from one grating to at least one next grating, the light is sent forward or transmitted to at least one next grating region or grating.

[0041] In such Figure 2 In the embodiment indicated by the arrow, any grating region 112 in the array other than the last grating region 114 may also additionally pass a portion of the light received from the previous grating to the coupling grating 104.

[0042] In such Figure 2 In the embodiments indicated by the arrows, for example, when forwarding light to the next grating or grating region, one or more grating regions 112 may cause the light to partially bypass one or more grating regions. In one embodiment, when forwarding light to the next grating or grating region, one or more grating regions 112 other than the last grating region 114 may cause the light to partially bypass one or more grating regions.

[0043] Figure 3 Another example of a light guide 106 for an augmented or virtual reality glasses device 10, viewed from above, is shown. In this example, the coupling grating 102 diffracts light toward a first grating region 112, which in turn diffracts a portion of the light toward a second grating region 114, the last grating region before the coupling grating 104. The three grating regions 112, 114, and 114' have different grating angles, meaning their lines are oriented differently. The second grating region 114 diffracts the light it receives from the first grating region 112 toward the coupling grating 104. In this example, the first grating region 112 allows a portion of the light from the coupling grating 102 to propagate to a third grating region 114' adjacent to the second grating region 114. The third grating region 114' diffracts the light it receives from the first grating region 112 toward the coupling grating 104. In this configuration, light can propagate in parallel paths.

[0044] The additional grating 110 may also be referred to as a folded grating. This array causes the light to be redirected at least once in the lateral direction in the optical path from the input grating 102 to the output grating 104, the lateral direction being perpendicular to the thickness direction of the light guide 106.

[0045] exist Figures 3 to 6In the illustrated implementation example, the array may include at least two grating regions 112, 112', 114, 114', each grating region causing light to be redirected or diffracted in the lateral direction in the optical path from the input grating 102 to the output grating 104. Figures 3 to 6 and Figure 8 The arrows in the diagram indicate the propagation of light within the light guide tube 106.

[0046] In one embodiment, the coupling grating 102 can redirect light to a direction deviating from the straight line between the coupling grating 102 and the coupling grating 104, while guiding the light to the first grating 112.

[0047] In one embodiment, at least one of at least two grating regions 112, 112', 114, 114' can deflect light away from a direction parallel to the straight line between the input grating 102 and the output grating 104.

[0048] Light propagates in a zigzag path within the light guide 106, the zigzag path having a directional component parallel to the transverse direction of the light guide 106. Therefore, the array causes the light to be redirected at least once in the transverse direction along the optical path from the input grating 102 to the output grating 104, the transverse direction being perpendicular to the direction of the vertical thickness of the light guide 106.

[0049] Some additional variations in grating regions 112, 112', 114, and 114' are present. Figures 4 to 6 As shown in the image. Figure 4 An example layout of a light guide 106 is shown, which has two grating regions 112, 114, and the first grating region 112 directs light to the last grating region 114, which in turn directs light to the coupling grating 104.

[0050] Figure 5 Showing something similar to Figure 4 Example. In this example, the first grating region 112 directs the light to the coupling grating 104, and the last grating region 114 further extends the beam propagating through it before directing the beam to the coupling grating 104.

[0051] Figure 6 Show Figure 4 and Figure 5 Examples of combinations of the two previous cases are shown. In all these cases, the shape and area of ​​the additional grating 110 and grating regions 112, 112', 114, 114', as well as the positions of the coupled grating 102 and the coupled grating 104, can be adjusted.

[0052] The grating period and angle can also be selected so that there are a finite number of propagation directions for light rays coupled into the light guide 106 at a specific angle. Therefore, the linear combination can be based on integer constants. In this way, the image quality is good and ghosting can be limited or eliminated.

[0053] In one embodiment, the orientation of the coupling grating 102, the additional grating 110, and the coupling grating 104, as well as the geometric surface parameters of the light guide 106, can be optimized relative to each other. In another embodiment, the orientation of the coupling grating 102, at least one of the grating regions 112, 112', 114, 114', and the coupling grating 104, as well as the geometric surface parameters of the light guide 106, can be optimized relative to each other. Surface parameters can be considered as properties or characteristics of a surface. Geometric surface parameters can be one of the following: area and shape.

[0054] When the direction of light arriving at the grating is known, the orientation of the grating ridges and / or grating grooves determines the vertical and transverse directions of the diffracted light. Another parameter is the density of the grating ridges and / or grating grooves, which defines the angle at which light diffracts from the grating in the vertical and transverse directions. These parameters are limited by the fact that only a predetermined range of angles of light in the vertical direction results in total internal reflection. In this way, various desired light paths through the waveguide 106 can be designed and determined. The height, width, and / or profile shape of the grating lines can also be varied to achieve desired light propagation in the waveguide 106 and / or to realize the design objectives of the waveguide 106.

[0055] In one embodiment, the number of grating regions 112, 112', 114, 114' and the geometric surface parameters of the waveguide 106 can be optimized relative to each other. A greater number of grating regions 112, 112', 114, 114' allows for more independent and efficient setting of the positions of the coupling grating 102 and the coupling grating 104; however, a greater number of grating regions 112, 112', 114, 114' can also increase the area of ​​the waveguide 106. To maintain regional optimization, other parameters such as the ridge orientation, ridge density, shape of the grating regions 112, 112', 114, 114', and total area should be considered.

[0056] In one implementation, the line density (i.e., the number of lines per unit length in grating regions 112, 112', 114, 114') and the geometric surface parameters of the light guide 106 can be optimized relative to each other. These lines can be understood as representing grating ridges or grating grooves. Sometimes, sharp bending angles of light may be useful, while in some other cases, obtuse angles may be more desirable.

[0057] In one implementation, the number, line density, and geometric surface parameters of the grating regions 112, 112', 114, 114' and the light guide 106 can be optimized relative to each other.

[0058] In one embodiment, the shape of the additional grating 110 and the geometric surface parameters of the light guide 106 can be optimized relative to each other. The shape of the additional grating can be, for example, a polygon, a circle, or an ellipse. In one embodiment, the shape of the grating regions 112, 112', 114, 114' and the geometric surface parameters of the light guide 106 can be optimized relative to each other. The shape of the grating regions 112, 112', 114, 114' can be, for example, a polygon, a circle, or an ellipse.

[0059] In other words, the positions of the input grating 102 and the output grating 104 can be adjusted and set in a desired manner based on the orientation of the grating ridge / groove, the density of the grating ridge / groove of the additional grating 110, and the grating regions 112, 112', 114, 114' relative to each other, while the shape and / or area of ​​the light guide tube are predetermined.

[0060] Figure 8 An example of the operation of the light guide 106 as seen from the side is shown. Due to total internal reflection, the light is refracted in the vertical direction (parallel to the thickness of the light guide 106). Due to diffraction from grating regions 112, 112', 114, 114' and diffraction between grating regions 112, 112', 114, 114', the light also exhibits a zigzag pattern in the transverse direction (perpendicular to the thickness of the light guide 106), such as... Figures 2 to 7 As shown.

[0061] Figure 9 An example is shown where the light guide 106 includes multiple grating regions 112, 112', 114, 114' shaded in different directions to illustrate the different directions of the grating vector. Directly adjacent grating regions 112, 112', 114, 114' are directly connected to each other, giving them a common interface 116. That is, there is no physical, material, or optical structure between them that is required for the common interface. The multiple grating regions may be located between the input grating 102 and the output grating 104 (which is why only grating regions 112, 112', 114, 114' are shown in conjunction with the input grating 102 and the output grating 104, respectively).

[0062] Figure 10 Showing something similar to Figure 9 The difference is that the input grating 102 is physically separated from the additional grating 110 and the output grating 104.

[0063] Figure 11 Showing something similar to Figure 9and Figure 10 Another example of the example, the difference being that the input grating 102 and the output grating 104 are physically separated from the additional grating 110.

[0064] Figure 12 An example of two different wavelength propagation directions in the wave vector space of the light guide 106 is shown. The vertical axis is the relative wavenumber in the y-direction, and the horizontal axis is the relative wavenumber in the x-direction. Light enters at the origin, which is in the middle of the circle, and diffracts in one of six permissible directions as it interacts with the grating region. In this example, the six permissible directions are possible within the light guide 106 because different grating regions can have grating vectors in different directions. The diffracted light can propagate within the light guide 106 while remaining within the loop (between two concentric circles). Each point represents a propagation direction within the light guide 106. Figure 12 Larger dots represent longer wavelengths of light (e.g., red), while smaller dots represent shorter wavelengths of light (e.g., blue).

[0065] Figure 13 This is a flowchart of the operation method of the light guide 106 of the augmented or virtual reality glasses device 10. In step 900, light is guided from the coupling grating 102 to the coupling grating 104 via a plurality of grating regions 112, 112', 114, 114' of the additional grating 110 in each optical path within the light guide 106. The light guide 106 has the coupling grating 102, the coupling grating 104, and the additional grating 110. At least two grating regions 112, 112', 114, 114' have a common physical interface 116 and grating vectors in different directions. In step 902, the light in each optical path is coupled out from the coupling grating 104. In these steps, each of the grating vectors of the additional grating 110, the coupled grating 102, and the coupled grating 104 is a linear combination of two non-parallel and common basis vectors, and the sum of the grating vectors of the coupled grating 102, the additional grating 110, and the coupled grating 104 is zero for each optical path.

[0066] Figure 14 This is a flowchart of a method for manufacturing the light guide 106 of an augmented or virtual reality glasses device 10. In step 1000, an additional grating 110 with multiple grating regions 112, 112', 114, 114' is formed between the input grating 102 and the output grating 104, and at least two grating regions 112, 112', 114, 114' have a common physical interface 116 and grating vectors in different directions.

[0067] In step 1002, each of the grating vectors of the additional grating 110, the input grating 102, and the output grating 104 is set as a linear combination of two non-parallel, common basis vectors. In step 1004, the sum of the grating vectors of the input grating 102, the additional grating 110, and the output grating 104 is set to zero for each optical path and configured to guide light from the input grating 102 to the output grating 104 via the additional grating 110 and couple the light out from the output grating 104.

[0068] An exit pupil expander (EPE) as an additional grating 110 can be used in the light guide 106 to distribute the coupled light over a larger area before coupling out, but this requires more space and material due to the physical separation between them. This paper describes a single additional EPE grating 110 having multiple grating regions 112, 112', 114, 114', which are positioned such that coupled light propagating within the light guide 106 is at least partially guided to another EPE region before entering the coupling out grating 104. This arrangement of the additional grating 110 gives more freedom in the design and arrangement of the grating regions in the light guide 106, allowing for a more compact and suitable light guide layout within the desired frame of the AR / MR glasses. The additional grating 110 can also be used to reduce the required surface area.

[0069] It will be apparent to those skilled in the art that the inventive concept can be implemented in various ways as technology advances. The present invention and its embodiments are not limited to the exemplary embodiments described above, but can be varied within the scope of the claims.

Claims

1. A light guide for an augmented or virtual reality glasses device, comprising an additional grating disposed between an input grating and an output grating, wherein, The additional grating includes an array of multiple grating regions arranged continuously in the propagation direction between the input grating and the output grating, wherein a first grating region of the array is configured to receive light from the input grating, and a last grating region of the array is configured to forward light to the output grating, and the additional grating is a single integrated grating. Any grating region in the array other than the last grating region is configured to transmit light received from the previous grating to at least one next additional grating. At least two directly adjacent grating regions have a common physical interface through grating vectors that are directly connected to each other and have different orientations; Each of the additional grating, the coupling grating, and the coupling out grating is a linear combination of two non-parallel gratings with a common basis vector, and the sum of the grating vectors of the coupling grating, the additional grating, and the coupling out grating is zero for each optical path. This configuration guides light from the coupling grating to the coupling out grating via the additional grating and allows light to couple out from the coupling out grating. The area of ​​the additional grating is the area of ​​the exit pupil expander, and the areas of each exit pupil expander are integrated to form a single exit pupil expander structure.

2. The apparatus according to claim 1, wherein, The angle between the directions of the basis vectors is at least one of the following: 45°, 60°, and 90°.

3. The apparatus according to claim 1, wherein, The first of the two basis vectors has a different magnitude than the second of the two basis vectors.

4. The apparatus according to claim 1, wherein, The linear combination of the basis vectors is formed by multiplying at least one of the basis vectors by an integer and adding the basis vectors together.

5. The apparatus according to claim 1, wherein, The array includes at least two grating regions, each of which is configured such that light is diverted laterally in the optical path from the input grating to the output grating.

6. The apparatus according to claim 1, wherein, The orientations of the coupling grating, the additional grating, and the coupling out grating, as well as the geometric surface parameters of the light guide, are optimized relative to each other.

7. The apparatus according to claim 6, wherein, The geometric surface parameters are one of the following: area and shape.

8. The apparatus according to any one of the preceding claims, wherein, The number of grating regions and the geometric surface parameters of the light guide are optimized relative to each other.

9. The apparatus according to any one of the preceding claims, wherein, The line density of the grating region and the geometric surface parameters of the light guide are optimized relative to each other.

10. The apparatus according to any one of the preceding claims, wherein, The shape of the additional grating and the geometric surface parameters of the light guide are optimized relative to each other.

11. An augmented or virtual reality glasses device, comprising a light guide, the light guide including a single additional grating disposed between an input grating and an output grating; wherein, The additional grating includes an array of multiple grating regions arranged continuously in the propagation direction between the input grating and the output grating, wherein a first grating region of the array is configured to receive light from the input grating, and a last grating region of the array is configured to forward light to the output grating, and the additional grating is a single integrated grating. Any grating region in the array other than the last grating region is configured to transmit light received from the previous grating to at least one next additional grating. At least two directly adjacent grating regions have a common physical interface through grating vectors that are directly connected to each other and have different orientations; Each of the additional grating, the coupling grating, and the coupling out grating is a linear combination of two non-parallel gratings with a common basis vector, and the sum of the grating vectors of the coupling grating, the additional grating, and the coupling out grating is zero for each optical path. This configuration guides light from the coupling grating to the coupling out grating via the additional grating and couples the light out from the coupling out grating. The area of ​​the additional grating is the area of ​​the exit pupil expander, and the areas of each exit pupil expander are integrated to form a single exit pupil expander structure.

12. A method of operating a light guide for an augmented or virtual reality glasses device, the method comprising: In each optical path within a light guide, light is guided from an input grating to an output grating via multiple grating regions of an additional grating. The light guide has an input grating, an output grating, and an additional grating. The additional grating comprises an array of multiple grating regions arranged continuously in the propagation direction between the input grating and the output grating. At least two directly adjacent grating regions have a common physical interface through grating vectors that are directly connected to each other and have different orientations. Light from the input grating is received through a first grating region of the array, and the light is forwarded to the output grating through a last grating region of the array. The additional grating is a single integrated grating. Any grating region in the array other than the last grating region is configured to transmit light received from the previous grating to at least one next additional grating. The light from each optical path is coupled out from the coupling grating, wherein, Each of the additional grating, the coupled-in grating, and the coupled-out grating is a linear combination of two non-parallel gratings that share a common basis vector, and the sum of the grating vectors of the coupled-in grating, the additional grating, and the coupled-out grating is zero for each optical path; The area of ​​the additional grating is the area of ​​the exit pupil expander, and the areas of each exit pupil expander are integrated to form a single exit pupil expander structure.

13. A method for manufacturing a light guide for an augmented or virtual reality glasses device, the method comprising: An additional grating is formed, comprising an array of multiple grating regions arranged continuously in the propagation direction between an input grating and an output grating, wherein a first grating region of the array is configured to receive light from the input grating, and a last grating region of the array is configured to forward light to the output grating, such that at least two directly adjacent grating regions have a common physical interface through grating vectors that are directly connected to each other and have different directions, and any grating region in the array other than the last grating region is configured to pass light received from a previous grating to at least one next additional grating, wherein the additional grating is a single integrated grating; Each of the grating vectors of the additional grating, the coupled-in grating, and the coupled-out grating is set as a linear combination of two non-parallel but common basis vectors; The sum of the grating vectors of the coupling grating, the additional grating, and the coupling out grating is set to zero for each optical path, which is configured to guide the light from the coupling grating to the coupling out grating via the additional grating and couple the light out from the coupling out grating; The area of ​​the additional grating is the area of ​​the exit pupil expander, and the areas of each exit pupil expander are integrated to form a single exit pupil expander structure.

14. The method according to claim 13, wherein the method comprises: Optimize the orientation of the coupling grating, the additional grating, and the coupling grating, as well as the geometric surface parameters of the light guide relative to each other.

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