Waveguide structure and AR device

Abstract

The utility model discloses a waveguide structure and AR equipment, and relates to the technical field of optical display.The waveguide structure comprises a first waveguide and a second waveguide which are arranged in a stacked mode, the first waveguide is provided with a first grating and a second grating, and the second waveguide is provided with a third grating and a fourth grating; the projections of the second grating and the third grating in the stacking direction are overlapped, the projections of the first grating and the fourth grating in the stacking direction are staggered, the grating structures of the first grating and the second grating are the same, the grating structures of the third grating and the fourth grating are the same, and an image light beam is coupled into the first waveguide through the first grating and is coupled out through the second grating. And after being coupled out, the third grating is coupled into the second waveguide and is coupled out by the fourth grating. According to the waveguide structure and the AR equipment provided by the invention, the processing difficulty of the waveguide structure can be reduced.

Description

Technical Field

[0001] The present application relates to the field of optical display technology, and in particular, to a waveguide structure and an AR device. Background Art

[0002] Augmented Reality (AR) technology is a technology that cleverly integrates virtual information with the real world. It widely uses multimedia, three-dimensional modeling, real-time tracking and registration, intelligent interaction, sensing and other technical means to simulate computer-generated text, images, three-dimensional models, music, video and other virtual information and apply them to the real world. The two types of information complement each other, thus achieving "enhancement" of the real world. Diffractive optical waveguides play an extremely important role in AR devices.

[0003] Specifically, the diffraction optical waveguide uses the principle of diffraction and total reflection of light to transmit image information from the image source to the position of the human eye. The diffraction optical waveguide includes a transparent medium such as plane glass, on which a coupling-in grating and a coupling-out grating are arranged. The image light beam generated by the image generation unit is irradiated on the coupling-in grating. The image light beam passes through the coupling-in grating, and the diffraction effect occurs, which changes the original propagation direction and enters the waveguide, forming an image light beam that meets the total reflection condition, and is transmitted in the waveguide. When it is transmitted to the coupling-out grating, the total reflection condition is destroyed, and the image light beam is coupled out to form output image light. The above-mentioned diffraction optical waveguide is a one-dimensional pupil expansion optical waveguide, which is the simplest waveguide configuration. Due to the lack of an intermediate turning grating, the image light beam can only be expanded in the horizontal direction, so that the visible range of the exit pupil is only relatively large in the horizontal direction. In order to achieve longitudinal exit pupil expansion, an intermediate turning grating is added to realize a two-dimensionally expanded exit pupil visual range. The grating period and grating direction between the three gratings need to be optimized so that the three grating vectors match each other to achieve expansion while ensuring the elimination of grating dispersion. In this way, the grating directions and grating periods of the three gratings are different, which makes the optical waveguide processing complicated. In addition, the transmission efficiency of the waveguide structure in the prior art is low. Utility Model Content

[0004] The purpose of this application is to provide a waveguide structure and an AR device, which can reduce the processing difficulty of the waveguide structure and improve the transmission efficiency.

[0005] An embodiment of the present application provides a waveguide structure on the one hand, which includes a first waveguide and a second waveguide arranged in a stacked manner. A first grating and a second grating are arranged on the first waveguide, and a third grating and a fourth grating are arranged on the second waveguide. The projections of the second grating and the third grating in the stacking direction overlap, and the projections of the first grating and the fourth grating in the stacking direction are staggered. Among them, the grating structures of the first grating and the second grating are the same, and the grating structures of the third grating and the fourth grating are the same. A first image beam is coupled into the first waveguide by the first grating and coupled out by the second grating. After being coupled out, it is coupled into the second waveguide by the third grating and coupled out by the fourth grating to form a first output light. Among them, the first grating and the second grating are arranged on the first side surface of the first waveguide, and a first reflecting element is arranged on the second side surface of the first waveguide. The projection of the first reflecting element in the stacking direction covers the projections of the first grating and the second grating in the stacking direction. The third grating and the fourth grating are arranged on the first side surface of the second waveguide, and a second reflecting element is arranged on the second side surface of the second waveguide. The projection of the second reflecting element in the stacking direction covers the projection of the third grating in the stacking direction.

[0006] As an implementable manner, the grating periods of the first grating, the second grating, the third grating, and the fourth grating are the same.

[0007] As an implementable manner, the grating directions of the first grating and the second grating are V1, and the grating directions of the third grating and the fourth grating are V2, and V1 is perpendicular to V2.

[0008] As an implementable manner, the first grating and the second grating are arranged on the first waveguide along a first direction, the third grating and the fourth grating are arranged on the second waveguide along a second direction, the first direction and the second direction are perpendicular to each other, and both are perpendicular to the stacking direction.

[0009] As an implementable manner, the first grating and the second grating are arranged on the side of the first waveguide close to the second waveguide, and the third grating and the fourth grating are arranged on the side of the second waveguide close to the first waveguide.

[0010] As an implementable manner, the projection of the first reflecting element in the stacking direction covers the projection of the fourth grating in the stacking direction, or a third reflecting layer is arranged on the first side surface of the first waveguide, and the projection of the third reflecting layer along the stacking direction covers the projection of the fourth grating.

[0011] As an implementable manner, the projection of the second reflecting element in the stacking direction covers the projection of the fourth grating in the stacking direction.

[0012] As an implementable manner, a fifth grating and a sixth grating are further disposed on the first waveguide, and a seventh grating and an eighth grating are further disposed on the second waveguide. The second image light beam is coupled into the first waveguide by the fifth grating and coupled out by the sixth grating. After being coupled out, it is coupled into the second waveguide by the seventh grating and coupled out by the eighth grating to form a second output light.

[0013] As an implementable manner, the optical information of the first output light and the second output light is the same.

[0014] Another aspect of the embodiments of the present application provides an AR device, including an optical engine and the above-mentioned waveguide structure disposed on the light-emitting side of the optical engine. The image light beam emitted by the optical engine forms an output image after being coupled into and out of the shown waveguide structure.

[0015] The beneficial effects of the embodiments of the present application include:

[0016] The waveguide structure provided by the present application includes a first waveguide and a second waveguide stacked. A first grating and a second grating are disposed on the first waveguide, and a third grating and a fourth grating are disposed on the second waveguide. The projections of the second grating and the third grating in the stacking direction overlap, and the projections of the first grating and the fourth grating in the stacking direction are staggered. The first image light beam is coupled into the first waveguide by the first grating and coupled out by the second grating. After being coupled out, it is coupled into the second waveguide by the third grating and coupled out by the fourth grating to form a first output light. Through two couplings out by the second grating and the fourth grating, two-dimensional pupil expansion is realized. The first grating and the second grating are located on the first waveguide and serve as the coupling-in grating and the coupling-out grating on the first waveguide. When the grating structures of the first grating and the second grating are the same, the preparation process of the first waveguide can be simplified and the processing difficulty can be reduced. Similarly, the third grating and the fourth grating are located on the second waveguide and serve as the coupling-in grating and the coupling-out grating on the second waveguide. When the grating structures of the third grating and the fourth grating are the same, the preparation process of the second waveguide can be simplified and the processing difficulty can be reduced. Therefore, the waveguide structure of the present application can simplify the preparation process of the waveguide structure and reduce the processing difficulty of the waveguide structure on the basis of realizing two-dimensional pupil expansion. Among them, the first grating and the second grating are disposed on the first side surface of the first waveguide, and a first reflecting element is disposed on the second side surface of the first waveguide. The projection of the first reflecting element in the stacking direction covers the projections of the first grating and the second grating in the stacking direction. The third grating and the fourth grating are disposed on the first side surface of the second waveguide, and a second reflecting element is disposed on the second side surface of the second waveguide. The projection of the second reflecting element in the stacking direction covers the projection of the third grating in the stacking direction. The first reflecting element reflects the image light beam leaked from the second side surface back into the first waveguide for total reflection propagation, thereby reducing the leakage of the image light beam and improving the coupling-in and coupling-out efficiency of the first optical waveguide. Similarly, the second reflecting element can avoid the leakage of the image light beam at the third grating and improve the coupling-in efficiency of the second waveguide. Therefore, the embodiments of the present application can also reduce the leakage of the image light beam and improve the transmission efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0018] Figure 1 One of the schematic structural diagrams of a waveguide structure provided by an embodiment of the present application;

[0019] Figure 2 An optical path diagram of an image light beam in a waveguide structure provided by an embodiment of the present application;

[0020] Figure 3 One of the schematic structural diagrams of the first waveguide of a waveguide structure provided by an embodiment of the present application;

[0021] Figure 4 One of the schematic structural diagrams of the second waveguide of a waveguide structure provided by an embodiment of the present application;

[0022] Figure 5 One of the schematic structural diagrams of a waveguide structure provided by an embodiment of the present application;

[0023] Figure 6 One of the schematic structural diagrams of the first waveguide of a waveguide structure provided by an embodiment of the present application;

[0024] Figure 7 The waveguide mode diagram in the first waveguide of a waveguide structure provided by an embodiment of the present application;

[0025] Figure 8 One of the schematic structural diagrams of the second waveguide of a waveguide structure provided by an embodiment of the present application;

[0026] Figure 9 The waveguide mode diagram in the second waveguide of a waveguide structure provided by an embodiment of the present application;

[0027] Figure 10 One of the schematic structural diagrams of a waveguide structure provided by an embodiment of the present application;

[0028] Figure 11 One of the schematic structural diagrams of the first waveguide of a waveguide structure provided by an embodiment of the present application;

[0029] Figure 12 One of the schematic structural diagrams of a waveguide structure provided by an embodiment of the present application;

[0030] Figure 13 This is the third schematic diagram of the structure of the second waveguide of the waveguide structure provided by the embodiment of the present application.

[0031] Reference numerals: 100 - waveguide structure; 110 - first waveguide; 111 - first grating; 112 - second grating; 120 - second waveguide; 121 - third grating; 122 - fourth grating; 131 - first reflective film; 132 - second reflective film. Detailed implementation manners

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. Usually, the components of the embodiments of the present application described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0033] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0034] In order to achieve two-dimensional pupil expansion, in the prior art, an input grating, a turning grating, and an output grating are arranged on a waveguide to expand the image light beam in two directions. Among them, the grating directions and grating periods of the input grating, the turning grating, and the output grating are all different, making the processing of the optical waveguide complex.

[0035] The embodiment of the present application provides a waveguide structure 100, as shown in Figure 1 and Figure 2As shown in the figure, it includes a first waveguide 110 and a second waveguide 120 arranged in a stacked manner. A first grating 111 and a second grating 112 are arranged on the first waveguide 110, and a third grating 121 and a fourth grating 122 are arranged on the second waveguide 120. The projections of the second grating 112 and the third grating 121 overlap in the stacking direction, and the projections of the first grating 111 and the fourth grating 122 are staggered in the stacking direction. Among them, the grating structures of the first grating 111 and the second grating 112 are the same, and the grating structures of the third grating 121 and the fourth grating 122 are the same. The first image beam is coupled into the first waveguide 110 by the first grating 111 and coupled out by the second grating 112. After being coupled out, it is coupled into the second waveguide 120 by the third grating 121 and coupled out by the fourth grating 122 to form a first output light. Among them, the first grating and the second grating are arranged on the first side surface of the first waveguide, and a first reflecting element is arranged on the second side surface of the first waveguide. The projection of the first reflecting element in the stacking direction covers the projections of the first grating and the second grating in the stacking direction. The third grating and the fourth grating are arranged on the first side surface of the second waveguide, and a second reflecting element is arranged on the second side surface of the second waveguide. The projection of the second reflecting element in the stacking direction covers the projection of the third grating in the stacking direction.

[0036] In the waveguide structure 100 according to the embodiment of the present application, the first waveguide 110 and the second waveguide 120 are arranged in a stacked manner to realize the serial propagation of the image beam. Specifically, a first grating 111 and a second grating 112 are arranged on the first waveguide 110 as the coupling grating and the output grating of the first waveguide 110; a third grating 121 and a fourth grating 122 are arranged on the second waveguide 120 as the coupling grating and the output grating of the second waveguide 120. As Figure 2 shown, the image light is coupled into the first waveguide 110 from the first grating 111, and after undergoing a finite number of total internal reflections in the first waveguide 110, it reaches the second grating 112. After being coupled out by the second grating 112, it is incident on the third grating 121, coupled into the second waveguide 120 by the third grating 121, and after undergoing a finite number of total internal reflections in the second waveguide 120, it reaches the fourth grating 122 and is coupled out by the fourth grating 122 to form an outgoing light beam and enter the viewer's eyes. During this process, the image beam is coupled out twice by the second grating 112 and the fourth grating 122 to realize two-dimensional pupil expansion.

[0037] Regarding Figure 2 , it should be noted that in order to more clearly show the propagation direction of the image beam in the first waveguide 110 and the second waveguide 120, the first waveguide 110 and the second waveguide 120 are not shown from the same perspective. Specifically, as Figure 2 shown in the figure, it is a view of the first waveguide 110 in the yz plane and a view of the second waveguide 120 in the xz plane.

[0038] When the grating structures of the first grating 111 and the second grating 112 are the same, the preparation process of the first waveguide 110 can be simplified. Similarly, when the grating structures of the third grating 121 and the fourth grating 122 are the same, the preparation process of the second waveguide 120 can be simplified, reducing the processing difficulty. That is, the waveguide structure 100 of the present application simplifies the preparation process of the waveguide structure 100 and reduces the processing difficulty of the waveguide structure 100.

[0039] Therefore, the waveguide structure 100 provided by the embodiments of the present application can simplify the preparation process of the waveguide structure 100 and reduce the processing difficulty of the waveguide structure 100 on the basis of realizing two-dimensional pupil expansion.

[0040] In addition, the first grating and the second grating are arranged on the first side surface of the first waveguide, and a first reflective film is arranged on the second side surface of the first waveguide. The projection of the first reflective film in the stacking direction covers the projections of the first grating and the second grating in the stacking direction. The third grating and the fourth grating are arranged on the first side surface of the second waveguide, and a second reflective film is arranged on the second side surface of the second waveguide. The projection of the second reflective film in the stacking direction covers the projection of the third grating in the stacking direction. The first reflective film reflects the image light beam leaked from the second side surface back into the first waveguide for total reflection propagation, thereby reducing the leakage of the image light beam and improving the coupling-in and coupling-out efficiency of the first optical waveguide. Similarly, the second reflective film can avoid the leakage of the image light beam at the third grating and improve the coupling-in efficiency of the second waveguide. Therefore, the embodiments of the present application can also reduce the leakage of the image light beam and improve the transmission efficiency.

[0041] It should be noted that the above uses the first reflective film as an example to illustrate the first reflective element, and the second reflective film as an example to illustrate the second reflective element. In actual applications, the first reflective element and the second reflective element can also be other reflective elements.

[0042] Among them, the projections of the second grating 112 and the third grating 121 in the stacking direction overlap, which can be partial overlap or complete overlap. Among them, when the projections of the second grating 112 and the third grating 121 completely overlap, the grating areas of the second grating 112 and the third grating 121 can be fully utilized, and the waste of the image light beam will not be caused.

[0043] In addition, the same grating structures of the first grating 111 and the second grating 112 mean that the grating periods and grating directions of the first grating 111 and the second grating 112 correspond to each other. Similarly, the same grating structures of the third grating 121 and the fourth grating 122 mean that the grating periods and grating directions of the third grating 121 and the fourth grating 122 correspond to each other.

[0044] It can be understood that in the first waveguide 110, the area of the first grating 111 is smaller than the area of the second grating 112, such as Figure 3As shown; in the second waveguide 120, the area of the third grating 121 is smaller than the area of the fourth grating 122, as Figure 4 shown.

[0045] The waveguide structure 100 provided by the present application includes a first waveguide 110 and a second waveguide 120 arranged in a stacked manner. A first grating 111 and a second grating 112 are arranged on the first waveguide 110, and a third grating 121 and a fourth grating 122 are arranged on the second waveguide 120. The projections of the second grating 112 and the third grating 121 overlap in the stacking direction, and the projections of the first grating 111 and the fourth grating 122 are staggered in the stacking direction. The image beam is coupled into the first waveguide 110 by the first grating 111 and coupled out by the second grating 112. After being coupled out, it is coupled into the second waveguide 120 by the third grating 121 and coupled out by the fourth grating 122. Through two couplings out by the second grating 112 and the fourth grating 122, two-dimensional pupil expansion is achieved. The first grating 111 and the second grating 112 are located on the first waveguide 110 and serve as the input grating and the output grating on the first waveguide 110. When the grating structures of the first grating 111 and the second grating 112 are the same, the preparation process of the first waveguide 110 can be simplified and the processing difficulty can be reduced; similarly, the third grating 121 and the fourth grating 122 are located on the second waveguide 120 and serve as the input grating and the output grating on the second waveguide 120. When the grating structures of the third grating 121 and the fourth grating 122 are the same, the preparation process of the second waveguide 120 can be simplified and the processing difficulty can be reduced. Therefore, the waveguide structure 100 of the present application can simplify the preparation process of the waveguide structure 100 and reduce the processing difficulty of the waveguide structure 100 on the basis of realizing two-dimensional pupil expansion.

[0046] Optionally, the grating periods of the first grating 111, the second grating 112, the third grating 121, and the fourth grating 122 are the same.

[0047] The same grating periods of the first grating 111, the second grating 112, the third grating 121, and the fourth grating 122 can further reduce the processing difficulty of the waveguide structure 100.

[0048] In an implementable manner of the embodiment of the present application, as Figure 6 and Figure 8 shown, the grating directions of the first grating 111 and the second grating 112 are V1, and the grating directions of the third grating 121 and the fourth grating 122 are V2, and V1 is perpendicular to V2.

[0049] Among them, the grating directions of the gratings on the first waveguide 110 and the grating directions of the gratings on the second waveguide 120 are perpendicular, so that the expansion directions of the first waveguide 110 for the image beam and the second waveguide 120 for the image beam are perpendicular. In this way, two-dimensional pupil expansion can be better achieved.

[0050] Figure 6 Top view of the first grating 111 and the second grating 112 on the first waveguide 110, as Figure 6 shown, the first grating 111 has a grating vector K11, a grating period d11, and a grating direction V11. The second grating 112 has a grating vector k12, a grating period d12, and a grating direction V12. The angle with the x-axis is θ11 = 180°, d12 = d11, that is, the grating periods of the first grating 111 and the second grating 112 are the same, the grating directions are in the same direction and opposite to each other.

[0051] Figure 7 Waveguide mode diagram of the grating distribution in the first waveguide 110. The small circle KTIR represents the first boundary for satisfying the total internal reflection standard in the waveguide, and the large circle Kmax represents the second boundary of the maximum wave vector in the waveguide. The wave vector boundary can be determined by the refractive index of the waveguide. Only when the wave vector of the light is in the region between the first boundary KTIR and the second boundary Kmax can the image beam propagate in the waveguide. If the wave vector of the light is outside the region, the light may leak out of the waveguide plate or not propagate at all. The specific waveguide process is as follows:

[0052] The image beam IN1 enters the first waveguide 110 from the region BOX0 and conducts to the right in the grating direction V11. The wave vector of the conducted light B1 is in the region BOX1. The output light OUT1 conducts in the direction of V12, and its wave vector region is in BOX2. According to waveguide theory, the path of the wave vector in this waveguide needs to be a closed loop to ensure the symmetry relationship between waveguide input and output.

[0053] Same as the first waveguide 110, Figure 8 Top view of the third grating 121 and the fourth grating 122 on the second waveguide 120, as Figure 8 shown, the third grating 121 has a grating vector K21, a grating period d21, and a grating direction V21. The fourth grating 122 has a grating vector k22, a grating period d22, and a grating direction V22. The angle with the x-axis is θ11 = 90°, d22 = d21, that is, the grating periods of the third grating 121 and the fourth grating 122 are the same, the grating directions are in the same direction and opposite to each other.

[0054] Figure 9 Waveguide mode diagram of the grating distribution in the second waveguide 120. The small circle KTIR represents the first boundary for satisfying the total internal reflection standard in the waveguide, and the large circle Kmax represents the second boundary of the maximum wave vector in the waveguide. The wave vector boundary can be determined by the refractive index of the waveguide. Only when the wave vector of the light is in the region between the first boundary KTIR and the second boundary Kmax can the image beam propagate in the waveguide. If the wave vector of the light is outside the region, the light may leak out of the waveguide plate or not propagate at all. The specific waveguide process is as follows:

[0055] The image beam IN1 enters the first waveguide 110 from the region BOX0 and conducts to the right side in the grating direction V21. The wave vector of the conducted light B1 is in the region BOX1. The output light OUT1 conducts in the direction V22, and its wave vector region is in BOX2. According to waveguide theory, the path of the wave vector in this waveguide needs to be a closed loop to ensure the symmetric relationship between the waveguide input and output.

[0056] Optionally, as Figure 3 , Figure 4 and Figure 5 shown, the first grating 111 and the second grating 112 are arranged on the first waveguide 110 along the first direction, and the third grating 121 and the fourth grating 122 are arranged on the second waveguide 120 along the second direction. The first direction and the second direction are perpendicular to each other and both are perpendicular to the stacking direction.

[0057] The projections of the second grating 112 and the third grating 121 overlap in the stacking direction. On the first waveguide 110, arranging the first grating 111 and the second grating 112 along the first direction, and on the second direction, arranging the third grating 121 and the fourth grating 122 along the second direction can make full use of the surface area on the first waveguide 110 and the second waveguide 120, thereby reducing the areas of the first waveguide 110 and the second waveguide 120, and further reducing the area of the waveguide structure 100.

[0058] In an implementable manner of the embodiment of the present application, as Figure 1 and Figure 5 shown, the first grating 111 and the second grating 112 are arranged on the side of the first waveguide 110 close to the second waveguide 120, and the third grating 121 and the fourth grating 122 are arranged on the side of the second waveguide 120 close to the first waveguide 110.

[0059] The above arrangement makes the first grating 111, the second grating 112, the third grating 121 and the fourth grating 122 all located between the first waveguide 110 and the second waveguide 120. In this way, the first waveguide 110 and the second waveguide 120 protect each other, thereby avoiding the use of an additional glass protective layer, reducing the overall thickness of the waveguide component, and thus reducing the volume of the waveguide component.

[0060] Embodiment 1;

[0061] Optionally, as Figure 3 and Figure 5 shown, the first grating 111 and the second grating 112 are arranged on the first side surface of the first waveguide 110, and a first reflective film 131 is arranged on the second side surface of the first waveguide 110. The projection of the first reflective film 131 in the stacking direction covers the projections of the first grating 111 and the second grating 112 in the stacking direction.

[0062] In practical applications, the coupling efficiency of the first grating 111 is limited, resulting in partial leakage of the image light beam through the first grating 111. In addition, at the second grating 112, there are diffracted light beams in two directions when the image light beam is coupled out, causing leakage of the image light beam facing away from the second waveguide 120. To avoid leakage at the second side surface of the first waveguide 110, a first reflective film 131 is provided at the second side surface. The projection of the first reflective film 131 in the stacking direction covers the projections of the first grating 111 and the second grating 112 in the stacking direction. The first reflective film 131 reflects the leaked image light beam back into the first waveguide 110 for total reflection propagation, thereby reducing the leakage of the image light beam and improving the coupling-in and coupling-out efficiencies of the first optical waveguide.

[0063] Embodiment 2

[0064] Different from Embodiment 1, as Figure 10 and Figure 11 shown, the projection of the first reflective film 131 in the stacking direction covers the projection of the fourth grating 122 in the stacking direction. Alternatively, a third reflective layer is provided on the first side surface of the first waveguide, and the projection of the third reflective layer in the stacking direction covers the projection of the fourth grating.

[0065] At the fourth grating 122, there are still diffracted light beams in two directions when the image light beam is coupled out, causing leakage of the image light beam passing through the first waveguide 110. Covering the projection of the first reflective film 131 in the stacking direction with the projection of the fourth grating 122 in the stacking direction, or covering the projection of the fourth grating with the projection of the third reflective layer in the stacking direction enables the first reflective film 131 or the third reflective layer to reflect the image light beam leaked from the first waveguide 110. Thereby reducing the leakage of the image light beam and improving the coupling-out efficiency of the second optical waveguide.

[0066] Embodiment 3

[0067] Based on Embodiment 1, as Figure 12 and Figure 13 shown, the third grating 121 and the fourth grating 122 are arranged on the first side surface of the second waveguide 120, and a second reflective film 132 is provided on the second side surface of the second waveguide 120. The projection of the second reflective film 132 in the stacking direction covers the projection of the third grating 121 in the stacking direction.

[0068] Similar to the first reflective film 131, the second reflective film 132 can avoid the leakage of the image light beam at the third grating 121 and improve the coupling-in efficiency of the second waveguide 120. Under the combined action of the first reflective film 131 and the second reflective film 132, the transmission efficiency of the waveguide structure 100 can be further improved.

[0069] Embodiment 4

[0070] Different from the second embodiment, the projection of the second reflection film 132 in the stacking direction covers the projection of the fourth grating 122 in the stacking direction.

[0071] The projection of the second reflection film 132 in the stacking direction covers the projection of the fourth grating 122 in the stacking direction, avoiding the leakage of the image light beam at the fourth grating 122 and improving the coupling-out efficiency of the second waveguide 120.

[0072] Embodiment Five

[0073] Based on the binocular AR device, in the embodiment of the present application, a fifth grating and a sixth grating are further provided on the first waveguide, and a seventh grating and an eighth grating are further provided on the second waveguide. The second image light beam is coupled into the first waveguide by the fifth grating and coupled out by the sixth grating. After being coupled out, it is coupled into the second waveguide by the seventh grating and coupled out by the eighth grating to form the second output light.

[0074] Among them, the fourth grating and the eighth grating respectively correspond to the two eyes of the observer, and the first output light and the second output light respectively enter the two eyes.

[0075] Specifically, the optical information of the first output light and the second output light is the same. When the optical information of the first output light and the second output light is the same, the information entering the two eyes is the same, improving the experience of the observer.

[0076] The embodiment of the present application also discloses an AR device, including an optical engine and the above-mentioned waveguide structure 100 disposed on the light-emitting side of the optical engine. The image light beam emitted by the optical engine forms an output image after being coupled in and out by the shown waveguide structure 100. This AR device includes the same structure and beneficial effects as the waveguide structure 100 in the foregoing embodiments. The structure and beneficial effects of the waveguide structure 100 have been described in detail in the foregoing embodiments and will not be repeated here.

[0077] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A waveguide structure, characterized in that: The invention comprises a first waveguide and a second waveguide which are stacked, wherein a first grating and a second grating are arranged on the first waveguide, and a third grating and a fourth grating are arranged on the second waveguide, and projections of the second grating and the third grating in a stacking direction overlap, and projections of the first grating and the fourth grating in a stacking direction are staggered, wherein the grating structures of the first grating and the second grating are the same, and the grating structures of the third grating and the fourth grating are the same, and a first image light beam is coupled into the first waveguide by the first grating and coupled out by the second grating, and after being coupled out, is coupled into the second waveguide by the third grating and coupled out by the fourth grating to form a first output light; The first grating and the second grating are arranged on a first side of the first waveguide, a first reflecting element is arranged on a second side of the first waveguide, and a projection of the first reflecting element in a stacking direction covers a projection of the first grating and the second grating in the stacking direction; The third grating and the fourth grating are arranged on the first side of the second waveguide, a second reflecting element is arranged on the second side of the second waveguide, and a projection of the second reflecting element in the stacking direction covers a projection of the third grating in the stacking direction.

2. The waveguide structure according to claim 1, characterized in that: The grating periods of the first grating, the second grating, the third grating and the fourth grating are the same.

3. The waveguide structure according to claim 1, characterized in that: The grating directions of the first grating and the second grating are V1, the grating directions of the third grating and the fourth grating are V2, and V1 is perpendicular to V2.

4. The waveguide structure according to claim 2, characterized in that: The first grating and the second grating are arranged on the first waveguide along a first direction, and the third grating and the fourth grating are arranged on the second waveguide along a second direction. The first direction and the second direction are perpendicular to each other and perpendicular to the stacking direction.

5. The waveguide structure according to claim 1, characterized in that: The first grating and the second grating are arranged on a side of the first waveguide close to the second waveguide, and the third grating and the fourth grating are arranged on a side of the second waveguide close to the first waveguide.

6. The waveguide structure according to claim 1, characterized in that: The projection of the first reflecting element in the stacking direction covers the projection of the fourth grating in the stacking direction, or a third reflecting layer is arranged on the first side surface of the first waveguide, and the projection of the third reflecting layer in the stacking direction covers the projection of the fourth grating.

7. The waveguide structure according to claim 1, characterized in that: The projection of the second reflective element in the stacking direction covers the projection of the fourth grating in the stacking direction.

8. The waveguide structure according to claim 1, characterized in that: A fifth grating and a sixth grating are also provided on the first waveguide, and a seventh grating and an eighth grating are also provided on the second waveguide. The second image light beam is coupled into the first waveguide by the fifth grating and coupled out by the sixth grating. After being coupled out, the second image light beam is coupled into the second waveguide by the seventh grating and coupled out by the eighth grating to form a second output light.

9. The waveguide structure according to claim 8, characterized in that: The first output light and the second output light have the same light information.

10. An AR device, characterized in that: It comprises an optical machine and a waveguide structure as described in any one of claims 1 to 9 arranged on the light-emitting side of the optical machine, wherein the image light beam emitted by the optical machine forms an output image after being coupled in and out by the waveguide structure.

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