Waveguide device, method for manufacturing a grating section in a waveguide device, and display device

Abstract

The present invention discloses a waveguide device, which includes a waveguide body, a first grating portion and a second grating portion provided on the waveguide body. The second grating portion is used to couple light into the waveguide body, and the first grating portion is used to expand the light propagating in the waveguide body in two directions and couple it out of the waveguide body. The first grating portion includes grating units arranged periodically in a two-dimensional direction, and the boundary of the grating units in the top view of the first grating portion is a shape surrounded by at least two curved edges. By adopting this grating unit structure for the grating units of the first grating portion in this waveguide device, compared with the waveguides used in the prior art, the processing difficulty of the grating in the waveguide device can be reduced, the processing efficiency can be improved, the processing cost can be reduced, and the mass production of the waveguide device is more facilitated. The present invention also discloses a method for manufacturing a grating portion in a waveguide device. The present invention also discloses a display device.

Description

Technical Field

[0001] The present invention relates to the technical field of augmented reality display, and in particular to a waveguide device. The present invention also relates to a method for manufacturing a grating portion in a waveguide device. The present invention also relates to a display device. Background Art

[0002] Augmented Reality (AR) technology refers to providing additional information (i.e., the so-called "augmentation") for users in the real world through certain technical means. This technology organically combines the images of the virtual world and the scenes of the real world, and through deep integration of the calculated information with the real world, it provides users with richer information and immersive experiences. In the information age, augmented reality, as one of the most direct information acquisition methods, has extremely broad application scenarios, such as military training, medical assistance, education and learning, the game industry, entertainment art, etc. It is widely regarded as the next-generation computing platform after the computer.

[0003] Augmented reality technology can be implemented through many hardware platforms. Among them, the most immersive one is the wearable augmented reality device, that is, AR glasses. The hardware form of this method is a simple pair of glasses, which guides light into the human eye through the microstructures on the lens surface. This hardware implementation method is the most convenient and is the mainstream technology of AR. The purpose of the AR lens is to guide the image from the microdisplay into the human eye through the lens. The grating waveguide scheme is a mainstream technical solution, and its basic principle is as Figure 1 shown. The surface of the waveguide 3 has a grating 1 and a grating 2. The light output by the micro-projector 4 is coupled into the waveguide 3 by the grating 1. The light propagates in the waveguide 3 by total internal reflection. Whenever it encounters another grating 2, a part of the light is coupled out, and the coupled-out light enters the human eye 5, so that the same image as the output of the micro-projector 4 can be seen. At the same time, the human eye 5 can see the real-world scene, and the two parts overlap to achieve the function of augmented reality.

[0004] However, for the waveguide used in the prior art, the grating processing method has a long cycle, high cost and is seriously dependent on equipment, so it is difficult to mass-produce. Summary of the Invention

[0005] In view of the above, the present invention provides a waveguide device, which can reduce the processing difficulty of the grating in the waveguide device compared with the prior art, improve the processing efficiency, reduce the processing cost, and is more suitable for mass production. The present invention also provides a method for manufacturing a grating portion in a waveguide device. The present invention also provides a display device.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A waveguide device includes a waveguide body, a first grating portion and a second grating portion provided on the waveguide body. The second grating portion is configured to couple light into the waveguide body, and the first grating portion is configured to couple light propagating in the waveguide body out of the waveguide body.

[0008] The first grating portion includes grating units arranged periodically in a two-dimensional direction. The boundary of the grating unit has a shape surrounded by at least two curved edges when viewed from the top of the first grating portion.

[0009] Preferably, the boundary of the grating unit has a shape surrounded by at least two curved edges when viewed from the top of the first grating portion. In the two-dimensional region of [-cos(30°)d / 2, cos(30°)d / 2]×[-d / 4, d / 4] where the grating unit is located, the boundary of the grating unit satisfies the following equation:

[0010]

[0011] where d is the period of the two-dimensional grating in two directions, and the value range of △ is (0, 2).

[0012] Preferably, the boundary of the grating unit has a shape surrounded by three curved edges when viewed from the top of the first grating portion, or the boundary of the grating unit has a shape surrounded by six curved edges when viewed from the top of the first grating portion.

[0013] Preferably, the second grating portion includes periodically arranged protrusions, and the protrusions are inclined with respect to the normal of the surface of the second grating portion.

[0014] Preferably, the protrusion includes a first side surface and a second side surface.

[0015] Preferably, the top of the first side surface is connected to the top of the second side surface, or the protrusion further includes a top surface connecting the top of the first side surface and the top of the second side surface.

[0016] Preferably, the light energy that can be received by the human eye and coupled out through the first grating portion decreases as the angle between the coupled-out light and the normal of the first grating portion increases, and the light energy that can be received by the human eye and coupled into the waveguide body through the second grating portion increases as the angle between the coupled-in light and the normal of the second grating portion increases.

[0017] Preferably, it further includes a reflection device provided on the side of the waveguide body away from the user's viewing side, configured to reflect the light in the waveguide body that is about to be emitted out of the waveguide body to the side away from the user's viewing side back into the waveguide body.

[0018] A method for fabricating a grating portion in a waveguide device, where the grating portion is applied to the first grating portion of the waveguide device as described above, includes:

[0019] Prepare a substrate and fabricate a photosensitive layer on the substrate;

[0020] Use two coherent light beams to intersect and irradiate the photosensitive layer of the substrate to expose the photosensitive layer;

[0021] Etch the substrate to form grating units on the substrate based on the periodic structure formed by the photosensitive layer;

[0022] Remove the remaining photosensitive layer on the substrate to obtain the grating portion.

[0023] A display device includes a projection device and the waveguide device described above, and the projection device is used to generate image light.

[0024] As can be seen from the above technical solutions, a waveguide device provided by the present invention includes a waveguide body and a first grating portion and a second grating portion provided on the waveguide body. The second grating portion is used to couple light into the waveguide body, and the first grating portion is used to couple the light propagating in the waveguide body out of the waveguide body. The first grating portion includes grating units arranged periodically in a two-dimensional direction, and the boundary of the grating units in the top view of the first grating portion is a shape surrounded by at least two curved edges. With this grating unit structure for the grating units in the first grating portion of the waveguide device of the present invention, compared with the waveguides used in the prior art, it can reduce the processing difficulty of the grating in the waveguide device, improve the processing efficiency, reduce the processing cost, and is more conducive to the mass production of the waveguide device.

[0025] The method for fabricating a grating portion in a waveguide device provided by the present invention can achieve the above beneficial effects.

[0026] The present invention also provides a display device that can achieve the above beneficial effects. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 Schematic diagram of the principle of a display device for a waveguide solution;

[0029] Figure 2 Front view of a waveguide device provided by an embodiment of the present invention;

[0030] Figure 3 is Figure 2 a top view of the waveguide device shown;

[0031] Figure 4 a top view of the first grating portion of an embodiment of the present invention;

[0032] Figure 5 a top view of the first grating portion of another embodiment of the present invention;

[0033] Figure 6 a top view of the first grating portion of another embodiment of the present invention;

[0034] Figure 7 a top view of the first grating portion of another embodiment of the present invention;

[0035] Figure 8 a schematic diagram of the second grating portion of an embodiment of the present invention;

[0036] Figure 9 a graph showing the variation of the diffraction efficiency of the second grating portion of an embodiment of the present invention with the incident angle α;

[0037] Figure 10 a schematic diagram of the second grating portion of another embodiment of the present invention;

[0038] Figure 11 a schematic diagram of the second grating portion of another embodiment of the present invention;

[0039] Figure 12(a) is a schematic diagram of large-angle incidence of light rays on the waveguide device according to an embodiment of the present invention;

[0040] Figure 12(b) is a schematic diagram of small-angle incidence of light rays on the waveguide device according to an embodiment of the present invention;

[0041] Figure 13(a) is a schematic diagram showing the variation of the light energy that can be received by the human eye and coupled out through the first grating portion with the angle between the coupled-out light ray and the normal of the first grating portion in an embodiment of the present invention;

[0042] Figure 13(b) is a schematic diagram showing the variation of the light energy coupled into the waveguide body through the second grating portion with the angle between the coupled-in light ray and the normal of the second grating portion in an embodiment of the present invention;

[0043] Figure 14 is a front view of a waveguide device provided by another embodiment of the present invention;

[0044] Figure 15 is a flowchart of a method for fabricating a grating portion in a waveguide device provided by an embodiment of the present invention. Detailed implementation manners

[0045] To enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0046] An embodiment of the present invention provides a waveguide device, including a waveguide body, a first grating portion and a second grating portion provided on the waveguide body. The second grating portion is used to couple light into the waveguide body, and the first grating portion is used to expand the light propagating in the waveguide body in two directions and couple the light out of the waveguide body.

[0047] The first grating portion includes grating units arranged periodically in a two-dimensional direction, and the boundary of the grating unit is a shape surrounded by at least two curved edges when viewed from the top view of the first grating portion.

[0048] The waveguide body is a waveguide structure capable of guiding the propagation of light. Light is coupled into the waveguide body through the second grating portion. When the light propagating in the waveguide body by total reflection reaches the first grating portion, the first grating portion expands the light in two directions and couples the light in the waveguide body out of the waveguide body. Among them, the boundary of the grating unit in the top view of the first grating portion refers to the boundary that defines the range of the grating unit obtained in the top view of the first grating portion. The curved edge refers to an edge with a curved shape. The boundary of the grating unit surrounded by at least two curved edges means that the boundary of the grating unit includes at least two curved edges.

[0049] In the waveguide device of the present embodiment, the grating unit of the first grating portion has a boundary surrounded by at least two curved edges. The grating unit of the first grating portion in this waveguide device adopts this grating unit structure, which can reduce the processing difficulty of the grating in the waveguide device compared with the waveguide used in the prior art, improve the processing efficiency, reduce the processing cost, and is more conducive to the mass production of the waveguide device.

[0050] The following will describe this waveguide device in detail in conjunction with specific embodiments and the accompanying drawings. Please refer to Figure 2 and Figure 3 , Figure 2 is the front view of a waveguide device provided in this embodiment, Figure 3 is Figure 2Top view of the waveguide device shown. As can be seen from the figure, the waveguide device includes a waveguide body 10, a first grating portion 11 and a second grating portion 12 provided on the waveguide body 10. The second grating portion 12 is used to couple light into the waveguide body 10, and the first grating portion 11 is used to expand the light propagating in the waveguide body 10 in two directions and couple it out of the waveguide body 10.

[0051] Among them, the first grating portion 11 includes grating units arranged periodically in a two-dimensional direction. The boundary of the grating unit in the top view perspective of the first grating portion 11 is a shape surrounded by at least two curved edges. That the boundary is surrounded by at least two edges means that at least two edges included in the boundary are different edges that are distinguishable from each other. That the boundary of the grating unit is surrounded by at least two curved edges means that the boundary of the grating unit includes at least two curved edges. It can be that the boundary of the grating unit is surrounded by a preset number of curved edges. For example, the boundary can be surrounded by two curved edges, or the boundary can be surrounded by three curved edges or four curved edges. It can also be that in addition to including at least two curved edges, the boundary of the grating unit also includes edges of other shapes, that is, the boundary of the grating unit is surrounded by at least two curved edges and a certain number of edges of other shapes.

[0052] In one embodiment, please refer to Figure 4 , Figure 4 which is the top view of the first grating portion of this embodiment. As can be seen from the figure, the first grating portion 11 includes grating units 110 arranged periodically in direction 1 and direction 2, and the included angle between the two directions is 60°. For the grating units 110 included in the first grating portion 11, the boundary of the grating unit 110 obtained in the top view perspective of the first grating portion 11 is a shape surrounded by four curved edges. The arranged grating units 110 are arranged periodically along direction 1 and periodically along direction 2 respectively, and include two periods. In specific implementation, the degree of the included angle θ between direction 1 and direction 2 can be set accordingly according to the design requirements. In Figure 4 the included angle between direction 1 and direction 2 is 60 degrees, and in other embodiments, the included angle can be taken as other degrees according to the design requirements.

[0053] Specifically, in this embodiment, the boundary of the grating unit 110 obtained in the top view perspective of the first grating portion 11 is a shape surrounded by four curved edges. In the two-dimensional region range of [-cos(30°)d / 2, cos(30°)d / 2]×[-d / 4, d / 4] where the grating unit is located, the boundary of the grating unit satisfies the following equation:

[0054]

[0055] where d is the period of the two-dimensional grating in two directions, and the value range of △ is (0, 2).

[0056] In addition, when determining the boundary shape of the grating units of the first grating part 11 from the top-down view of the first grating part 11, the arrangement pattern of the grating units on the first grating part 11 can also be changed. For example, please refer to Figure 5 , Figure 5 which is a top view of the first grating part in yet another embodiment. The boundary shape of the grating unit 111 included in the first grating part 11 from the top-down view of the first grating part 11 is the same as that of the grating unit 110 shown in Figure 4 from the top-down view of the first grating part 11. However, the arrangement patterns of the grating units in the two embodiments are different. In specific implementation, after the boundary shape of the grating unit in the first grating part 11 from the top-down view is determined in the design, the arrangement pattern of the grating units on the first grating part can be set accordingly according to the application requirements.

[0057] Optionally, in other embodiments, the grating units included in the first grating part 11 are arranged periodically in a two-dimensional direction. The boundary of the grating unit from the top-down view of the first grating part 11 can be enclosed by connecting two curved edges or three curved edges, or the boundary of the grating unit from the top-down view of the first grating part 11 can also be enclosed by connecting other numbers of curved edges. In practical applications, it can be set accordingly according to the application requirements, and all are within the protection scope of the present invention. The specific shapes of each curved edge are not specifically limited in this embodiment, and the shape enclosed by connecting each curved edge of the boundary of the grating unit from the top-down view of the first grating part 11 is not specifically limited in this embodiment. Moreover, when the boundary shape of the grating units of the first grating part 11 from the top-down view of the first grating part 11 is determined, the arrangement pattern of the grating units on the first grating part 11 can also be changed. Please refer to Figure 6 , Figure 6 which is a top view of the first grating part in yet another embodiment. It can be seen that the first grating part 11 includes grating units 112 arranged periodically in direction 1 and direction 2. For the grating units 112 included in the first grating part 11, the boundary of the grating units 112 obtained from the top-down view of the first grating part 11 is a shape enclosed by connecting three curved edges. In other embodiments, it can be that the boundary shape of the grating unit from the top-down view of the first grating part 11 is the same as that of the grating unit 112 shown in Figure 6 from the top-down view of the first grating part 11, but the arrangement pattern of the grating units on the first grating part 11 is different. Please refer to Figure 7 , Figure 7 which is a top view of the first grating part in yet another embodiment. In this embodiment, for the grating units 113 included in the first grating part 11, the boundary of the grating units obtained from the top-down view of the first grating part 11 is a shape enclosed by connecting six curved edges.

[0058] Optionally, in other embodiments, for the grating units included in the first grating portion 11, the boundary of the grating unit in the top-down view of the first grating portion 11 may include at least two curved edges and other shaped edges, that is, the boundary of the grating unit is formed by connecting at least two curved edges and a certain number of other shaped edges.

[0059] Further, in the waveguide device of this embodiment, the second grating portion 12 includes periodically arranged protrusions that are inclined with respect to the normal of the surface of the second grating portion 12. Please refer to Figure 8 , Figure 8 FIG. is a schematic diagram of the second grating portion of an embodiment. It can be seen that the protrusions of the second grating portion 12 are periodically arranged in one-dimensional direction, and the protrusions are inclined with respect to the normal of the surface of the second grating portion 12. The second grating portion 12 specifically includes a first side surface 120, a second side surface 121, and a top surface 122. The top surface 122 connects the top of the first side surface 120 and the top of the second side surface 121. In this embodiment, the top surface 122 is a plane. In other embodiments, the top surface can also be of other shapes, which are all within the protection scope of the present invention. The second grating portion 12 of this structure needs to determine at least the following four parameters: the inclination angle θ1 of the first side surface 120, the inclination angle θ2 of the second side surface 121, the protrusion height h, the width Δ of the bottom of the protrusion, and the period d1. Wherein, the inclination angle θ1 of the first side surface 120 refers to the angle between the first side surface 120 and the surface of the second grating portion, the inclination angle θ2 of the second side surface 121 refers to the angle between the second side surface 121 and the surface of the second grating portion, the protrusion height h refers to the maximum distance from the top of the protrusion to the bottom of the protrusion, and the width Δ of the bottom of the protrusion refers to the distance between the edge where the bottom of the protrusion intersects the first side surface and the edge where the bottom of the protrusion intersects the second side surface. Optionally, the ranges of the respective parameters can be: θ1 = 10° to 50°, △θ = θ2 - θ1 = ±10°, △ = 0.1d1 to 0.8d1. Please refer to Figure 9 , Figure 9 FIG. is a graph showing the change of the diffraction efficiency of the second grating portion of this embodiment with the incident angle α. Among them, the inclination angle of the first side surface 120 of the second grating portion is 35°, the inclination angle of the second side surface 121 is 35°, and the width of the bottom of the protrusion is 0.5d1. By optimizing the various parameters of the second grating portion, a higher diffraction efficiency and a larger corresponding incident angle range can be obtained.

[0060] Please refer to Figure 10 , Figure 10 FIG. is a schematic diagram of the second grating portion of another embodiment. It can be seen that in this embodiment, the protrusions of the second grating portion 12 are periodically arranged in one-dimensional direction, and the protrusions are inclined with respect to the normal of the surface of the second grating portion 12. The second grating portion 12 specifically includes a first side surface 123 and a second side surface 124. The top of the first side surface 123 is connected to the top of the second side surface 124, and both the first side surface 123 and the second side surface 124 are planes. Please refer to Figure 11 ,Figure 11 It is a schematic diagram of the second grating portion of yet another embodiment. It can be seen that in this embodiment, the second grating portion 12 includes protrusions arranged periodically in one-dimensional direction. The protrusions specifically include a first side surface 125 and a second side surface 126. The top of the first side surface 125 is connected to the top of the second side surface 126, and both the first side surface 125 and the second side surface 126 are curved surfaces.

[0061] The waveguide device in this embodiment adopts a one-dimensional grating + two-dimensional grating. On the one hand, it can minimize the number of gratings to the greatest extent, so that the imaging effect can be achieved with only two gratings, which is more compact than the three-grating solution and greatly reduces the mass production difficulty. On the other hand, the second grating portion in this waveguide device adopts an asymmetric grating structure, so the diffraction efficiency of the second grating portion is also asymmetric, and this asymmetry can exactly compensate for the attenuation of the first grating portion. Preferably, in the waveguide device of this embodiment, the light energy that can be received by the human eye coupled out through the first grating portion decreases as the angle between the coupled-out light and the normal of the first grating portion increases, and the light energy that can be received by the human eye coupled into the waveguide body through the second grating portion increases as the angle between the coupled-in light and the normal of the second grating portion increases. Please refer to FIGS. 12(a) and 12(b). The thickness of the arrows in the figures represents the relative magnitude of the energy. FIG. 12(a) is a schematic diagram of the large-angle incidence of light in the waveguide device of this embodiment. The light propagates in the waveguide at a large angle, so the number of propagations is small. The light 100 that can enter the human eye only encounters the first grating portion 2 times, so the attenuation is small. FIG. 12(b) is a schematic diagram of the small-angle incidence of light in the waveguide device of this embodiment. The light propagates in the waveguide at a small angle, so the number of propagations is large. The light 200 that can enter the human eye encounters the first grating portion 4 times, so the attenuation is large. When the light propagates in the first grating portion, a part of the light is coupled out during each diffraction, which will cause energy attenuation. For example, if the first grating portion couples out 1% of the energy each time, then the remaining energy after 10 propagations is 0.99 10 ^10^ = 0.34, which will cause a tendency of attenuation in the image plane observed by the user. Please refer to FIGS. 13(a) and 13(b). FIG. 13(a) is a schematic diagram of the change in the light energy that can be received by the human eye coupled out through the first grating portion with the angle between the coupled-out light and the normal of the first grating portion in this embodiment, and FIG. 13(b) is a schematic diagram of the change in the light energy coupled into the waveguide body through the second grating portion with the angle between the coupled-in light and the normal of the second grating portion in this embodiment. And due to the high asymmetry of the diffraction efficiency of the second grating portion in the waveguide device of this embodiment, it can be designed such that the energy of the second grating portion compensates for the attenuation caused by the first grating portion. In this way, the display uniformity of the waveguide device can be greatly improved.

[0062] Further preferably, the waveguide device of this embodiment further includes a reflection device disposed on the side of the waveguide body away from the user's viewing side, which is used to reflect the light that is about to exit the waveguide body to the outside of the waveguide body away from the user's viewing side back into the waveguide body. Please refer to Figure 14 , Figure 14 FIG. Figure 14 is a front view of the waveguide device of another embodiment. A reflection device 13 is disposed on the side of the waveguide body 10 away from the user's viewing side. When the light propagating in the waveguide body 10 reaches the first grating portion 11, a part of the light will be coupled out of the waveguide body 10 to the user's viewing side, and another part of the light will be emitted to the outside of the waveguide body 10 away from the user's viewing side. By setting the reflection device 13, the waveguide device of this embodiment can reflect the light that is about to exit the waveguide body to the outside of the waveguide body away from the user's viewing side back into the waveguide body, more effectively improving the energy utilization rate of the waveguide device and reducing light leakage to ensure information security. Optionally, the reflection device 13 can be a semi-transmissive and semi-reflective film, which can be plated on the side of the waveguide body away from the user's viewing side. Or the reflection device 13 can be a semi-transmissive and semi-reflective mirror, which is attached to the side of the waveguide body away from the user's viewing side. Or the reflection device 13 can also be a wire grid polarizing film, or it can also be other optical elements, which are all within the protection scope of the present invention.

[0063] Exemplarily, in a specific example, the waveguide body 10 of the waveguide device is in a flat plate shape, made of optical glass with a high parallelism and a refractive index n between 1.1 and 3, and its thickness is 0.1 mm - 3 mm. The second grating portion 12 is a one-dimensional periodic structure with a grating period of d1 = 200 nm - 1000 nm. The first grating portion 11 is a two-dimensional periodic structure with two identical periods of d2, and an included angle of 60° is formed between the two periods. The relationship between the two-dimensional grating period d2 and the one-dimensional grating period d1 is d2 = d1 / cos30°, and the one-dimensional grating period direction exactly falls on the angular bisector of the two period directions of the two-dimensional grating. The grating groove depth range of the first grating portion 11 is 50 nm to 500 nm.

[0064] The embodiment of the present invention also provides a method for manufacturing a grating portion in a waveguide device. The manufactured grating portion is applied to the first grating portion of the waveguide device described above. Please refer to Figure 15 , and the manufacturing method includes the following steps:

[0065] S20: Prepare a substrate and form a photosensitive layer on the substrate.

[0066] The photosensitive layer is a light-sensitive substance that can be etched away when light irradiates the photosensitive layer and the irradiation light intensity reaches a certain range. Optionally, the photosensitive layer can use photoresist.

[0067] S21: Use two coherent light beams to intersect and irradiate the photosensitive layer of the substrate to expose the photosensitive layer.

[0068] Two coherent light beams intersect and are incident on the photosensitive layer of the substrate. When the two light beams converge and interfere, a set of interference fringes with periodically varying light intensity is formed. The converging interference light irradiates the photosensitive layer to expose the photosensitive layer and the substrate, thereby generating a periodic structure on the photosensitive layer. When specifically fabricating the grating units on the first grating portion, the included angle θ between the two intersecting light beams determines the period d of the periodic arrangement of the grating units. The relationship between the two is: d = 2λ / sin(θ / 2), where λ is the wavelength of the laser used for exposure. Therefore, the included angle between the two intersecting light beams can be determined according to the period of the grating units on the first grating portion designed. When specifically fabricating the grating units on the second grating portion, the substrate needs to be exposed twice. After the first exposure, the substrate is rotated by a certain angle α for the second exposure. The rotation angle α determines the included angle between the grating units in the two-dimensional direction of the second grating portion. Preferably, the two light beams can use two lasers with extremely high coherence.

[0069] S22: Etch the substrate, and etch to form grating units on the substrate based on the periodic structure formed on the photosensitive layer.

[0070] In the above step, by using two coherent light beams to expose the photosensitive layer, a periodic structure is formed on the photosensitive layer. In this step, the substrate is etched, and based on the periodic structure formed on the photosensitive layer, a periodic structure is etched on the substrate, thereby fabricating and forming grating units on the substrate.

[0071] S23: Remove the remaining photosensitive layer on the substrate to obtain the grating portion.

[0072] Exemplarily, for the grating units whose grating unit boundaries of the first grating portion in the above embodiment satisfy the following equation, two coherent lights vibrating in a sine wave can be used for interference fabrication, and the two lights intersect at an included angle of 60 degrees:

[0073] where the value range of △ is (0, 2).

[0074] The method of this embodiment uses the holographic exposure method to fabricate the first grating portion, which has high production efficiency. Compared with the method of fabricating gratings in the prior art, it can reduce the processing difficulty, facilitate mass production, and improve the production efficiency.

[0075] Correspondingly, an embodiment of the present invention further provides a display device, including an imaging device and the waveguide device described above, and the imaging device is used to generate image light rays. The image light rays are light rays carrying image information.

[0076] The display device of this embodiment, the first grating portion of the waveguide device includes grating units arranged periodically in a two-dimensional direction. The boundary of the grating units in the top-down view of the first grating portion is a shape surrounded by at least two curved edges. By adopting this grating unit structure for the grating units in the first grating portion of the waveguide device, compared with the waveguides used in the prior art, the processing difficulty of the gratings in the waveguide device can be reduced, the processing efficiency can be improved, the processing cost can be reduced, and it is more conducive to the mass production of the waveguide device.

[0077] The display device of this embodiment can be an augmented reality display device or can also be applied to a mixed reality display device.

[0078] The above has introduced in detail a waveguide device, a method for manufacturing a grating portion in a waveguide device, and a display device provided by the present invention. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can still be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A waveguide device, characterized in that, It includes a waveguide body, a first grating portion and a second grating portion provided on the waveguide body. The second grating portion is used to couple light into the waveguide body, and the first grating portion is used to expand the light propagating in the waveguide body in two directions and couple it out of the waveguide body; The first grating portion includes grating units arranged periodically in a two-dimensional direction, and the boundary of the grating unit is a shape surrounded by at least two curved edges when viewed from the top of the first grating portion; The boundary of the grating unit is a shape surrounded by four curved edges when viewed from the top of the first grating portion, and an outwardly convex arc is formed at the connection of adjacent two curved edges; or, the boundary of the grating unit is a shape surrounded by three curved edges when viewed from the top of the first grating portion, and an outwardly convex arc is formed at the connection of adjacent two curved edges; or, the boundary of the grating unit is a shape surrounded by six curved edges when viewed from the top of the first grating portion, and an outwardly convex arc is formed at the connection of adjacent two curved edges among the three curved edges on the left side, and an outwardly convex arc is formed at the connection of adjacent two curved edges among the three curved edges on the right side; The second grating portion includes periodically arranged protrusions, and the protrusions are inclined with respect to the normal direction of the surface of the second grating portion. The light energy that can be received by the human eye and is coupled out through the first grating portion decreases as the included angle between the coupled-out light and the normal direction of the first grating portion increases, and the light energy that can be received by the human eye and is coupled into the waveguide body through the second grating portion increases as the included angle between the coupled-in light and the normal direction of the second grating portion increases.

2. The waveguide device according to claim 1, characterized in that, The boundary of the grating unit is a shape surrounded by at least two curved edges when viewed from the top of the first grating portion. In the two-dimensional region of [-cos(30°)d / 2, cos(30°)d / 2]×[-d / 4, d / 4] where the grating unit is located, the boundary of the grating unit satisfies the following equation: where d is the period of the two-dimensional grating in two directions, and the value range of △ is (0, 2).

3. The waveguide device according to claim 1, characterized in that, The protrusion includes a first side surface and a second side surface.

4. The waveguide device according to claim 3, wherein, The top of the first side surface is connected to the top of the second side surface, or the protrusion further includes a top surface connecting the top of the first side surface and the top of the second side surface.

5. The waveguide device according to claim 1, characterized in that, It further includes a reflection device provided on the side of the waveguide body away from the user's viewing side, which is used to reflect the light in the waveguide body that is about to be emitted out of the waveguide body to the side away from the user's viewing side back into the waveguide body.

6. A method for fabricating a grating portion in a waveguide device, where the grating portion is applied to the first grating portion of the waveguide device according to any one of claims 1-5, characterized in that, It includes: Prepare a substrate and fabricate a photosensitive layer on the substrate; Use two coherent light beams to intersect and irradiate the photosensitive layer of the substrate to expose the photosensitive layer; Etch the substrate, and based on the periodic structure formed on the photosensitive layer, etch the grating units on the substrate; Remove the remaining photosensitive layer on the substrate to obtain the grating portion.

7. A display device, characterized in that, It includes an imaging device and the waveguide device according to any one of claims 1-5, and the imaging device is used to generate image light.

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