Optical waveguide device and AR device

Abstract

The application discloses an optical waveguide device and AR equipment, and belongs to the technical field of augmented reality. The optical waveguide device comprises a first structure waveguide sheet, a second structure waveguide sheet and a coupling-in light machine. The first structure waveguide sheet comprises two first substrates and a plurality of first beam splitters arranged along a first direction and embedded between the two first substrates, the first beam splitters are arranged at a first included angle with a second direction, the first included angle is alpha, alpha is equal to 45°-theta, the second structure waveguide sheet comprises two second substrates and a plurality of second beam splitters arranged along a second direction and embedded between the two second substrates, the second structure waveguide sheet is arranged along the second direction with the first structure waveguide sheet, the second beam splitters are arranged at a second included angle with the first direction, the second included angle is beta, beta is equal to 45°-theta, and the exit pupil of the coupling-in light machine is arranged at a third included angle with the second direction, the third included angle is theta. The optical waveguide device and the AR equipment improve the volume, the observation position of the human eye, the light energy utilization rate and the use effect.

Description

Technical Field

[0001] This invention relates to the field of augmented reality technology, and in particular to an optical waveguide device and an AR device. Background Technology

[0002] Augmented Reality (AR) technology is a technique that cleverly integrates virtual information with the real world. Head-mounted displays using AR technology allow people to view their surroundings while virtual images are projected onto their eyes, holding significant importance in fields such as military, industry, entertainment, medicine, and transportation. Currently, the main technologies used in transmissive head-mounted displays for AR include Birdbath, prisms, freeform surfaces, and optical waveguides. Compared to other technologies, head-mounted displays using optical waveguides are smaller in size.

[0003] In existing technologies, such as Figure 1 As shown, the two-dimensional waveguide sheet comprises three parts: an upper structure waveguide sheet 1', a lower structure waveguide sheet 2', and a coupling structure 3'. The main function of the coupling structure 3' is to couple the parallel light emitted from the optomechanical system into the upper structure waveguide sheet 1'. The upper structure waveguide sheet 1' includes two parallel first surfaces 12' and second surfaces 13', and a series of parallel first beam splitters 11' are embedded between the first surfaces 12' and second surfaces 13'. The upper structure waveguide sheet 1' is used to couple the parallel light emitted from the optomechanical system into the upper structure waveguide sheet 1'. The exit pupil of structure 3' is deflected, and each first beam splitter 11' will image the exit pupil once, thereby achieving pupil expansion in the horizontal direction; the lower structural waveguide 2' is similar to a normal one-dimensional array waveguide, which includes two parallel third surfaces and a fourth surface, and a series of parallel second beam splitters embedded between the third surface and the fourth surface. The lower structural waveguide 2' is used to couple out the beam that has been deflected by the upper structural waveguide 1', so that it can be received by the human eye and achieve pupil expansion in the vertical direction.

[0004] Figure 2 The optical path diagram of light propagating from one end to the other within the upper waveguide 1' is given. The path length of the light within the upper waveguide 1' is 2L. When the light propagates from one end to the other on the surface of the upper waveguide 1', the path length is D, and the incident angle is A. From the geometric relationship in the diagram, we know that D = 2L × sinA. This formula can be understood as the equivalent length or unfolded length of a waveguide with width D for a light with an incident angle of A being D / sinA. Therefore, for a beam splitter with a spacing of d, the equivalent spacing or unfolded spacing for a light with an incident angle of A is d / sinA.

[0005] Taking a typical two-dimensional waveguide sheet with the above structure as an example, assuming the mirror spacing is small enough, Figure 3An equivalent optical path diagram of the upper structure waveguide sheet 1' is given, wherein the inclination angle of the first beam splitter 11' is 45°, the thickness of the two-dimensional waveguide sheet is 1.7 mm, the glass material is H-BAK5 (n=1.56), the diagonal field of view of the in-coupled image in the two-dimensional waveguide sheet is 55° (a 16:9 screen is adopted, and the horizontal field of view x vertical field of view is 48.8°x28.63°), the exit pupil of the in-coupling optical engine is 5.5 mm, the exit pupil distance is 20 mm, and the horizontal eyebox is 10 mm. According to the given parameters, the total reflection critical angle A c is A c = sin -1 (1 / n). Considering the assembly tolerance and the distortion of the designed optical engine, the minimum incidence angle in the two-dimensional waveguide sheet should be slightly greater than the critical angle 39.87°, so the total reflection transmission angle of the light in the two-dimensional waveguide sheet ranges from 40.88° to 61.92°, and the central incidence angle is 50°. The angle between the light in the lower structure waveguide sheet 2' and the vertical direction is 15.36°, and the angle between the light exiting from the lower structure waveguide sheet 2' and the vertical direction is 24.4°. According to the total reflection critical angle, the equivalent length or the unfolded length of the light in the lower structure waveguide sheet 2' is about 21.12 mm. According to the obtained data and the optical path reversibility principle, the equivalent height of the upper structure waveguide sheet 1' is about 28.98 mm, and the equivalent length is about 65.9 mm. According to the total reflection critical angle, the actual size of the upper structure waveguide sheet is about 50.48 mm x 22.2 mm. If six mirrors are embedded in the lower structure waveguide sheet 2', according to the design idea of the ordinary one-dimensional waveguide sheet, considering the processing technology, the height of the lower structure waveguide sheet 2' is at least 23 mm, such as Figure 4 the height of the lower structure waveguide sheet 2' is 23.46 mm.

[0006] According to the above analysis, Figure 4 the shape of the ordinary two-dimensional waveguide sheet with a diagonal field of view of 55° is given. It can be seen that, in this structure, the actual position of the human eye should be located between the upper structure waveguide sheet 1' and the lower structure waveguide sheet 2', and the best position of the human eye is located at the lower structure waveguide sheet 2'. The deviation between the actual position of the human eye and the best position of the human eye is large, and the Figure 3 It can be seen that the structure of the upper structure waveguide sheet 1' outside the boundary light is for structure, and there are too many redundant structures, which increases the volume and weight of the two-dimensional waveguide sheet. In addition, the redundant structure increases the number of first beam splitters 11' through which the light reaches the eyebox, reduces the light energy utilization rate, and reduces the brightness of the system. SUMMARY

[0007] An object of the present application is to provide an optical waveguide device, which compresses the volume, improves the observation position of the human eye, and improves the light energy utilization rate and use effect of the optical waveguide device.

[0008] To achieve the above object, the present application adopts the following technical solutions:

[0009] An optical waveguide device comprises:

[0010] A first structure waveguide sheet comprises two first substrates and a plurality of first beam splitters arranged along a first direction and embedded between the two first substrates, the first beam splitters are arranged at a first included angle with a second direction, the first included angle is α, wherein α = 45°-θ;

[0011] A second structure waveguide sheet comprises two second substrates and a plurality of second beam splitters arranged along a second direction and embedded between the two second substrates, the second structure waveguide sheet is arranged along the second direction with the first structure waveguide sheet, the second beam splitters are arranged at a second included angle with the first direction, the second included angle is β, wherein β = 45°-θ;

[0012] An exit pupil of a light coupling machine is arranged at a third included angle with the second direction, the third included angle is θ.

[0013] Optionally, the plurality of first beam splitters are arranged in parallel and at intervals, and the plurality of second beam splitters are arranged in parallel and at intervals.

[0014] Optionally, the first structure waveguide sheet comprises a plurality of first glass stacks sequentially bonded along the first direction, and bonding surfaces of two adjacent first glass stacks form the first beam splitters;

[0015] The second structure waveguide sheet comprises a plurality of second glass stacks sequentially bonded along the second direction, and bonding surfaces of two adjacent second glass stacks form the second beam splitters.

[0016] Optionally, the plurality of first glass stacks have the same thickness along the first direction, and the plurality of second glass stacks have the same thickness along the second direction.

[0017] Optionally, the plurality of first glass stacks are arranged in parallel, and the plurality of second glass stacks are arranged in parallel.

[0018] Optionally, the first substrate on one side and the second substrate are made of the same substrate, and the first substrate on the other side and the second substrate are made of the same substrate.

[0019] Optionally, the optical waveguide device further comprises an auxiliary structure, and the auxiliary structure is arranged on both sides of the first structure waveguide sheet along the first direction.

[0020] Optionally, the auxiliary structure comprises two third substrates and an auxiliary glass stack embedded between the two third substrates, the first substrate on one side and the third substrate are made of the same substrate, and the first substrate on the other side and the third substrate are made of the same substrate.

[0021] Another object of the present application is to provide an AR device.

[0022] To achieve the above object, the present application adopts the following technical solutions.

[0023] The AR device comprises the optical waveguide device, compresses the volume, improves the observation position of the human eye, and improves the light energy utilization rate of the optical waveguide device and the use effect.

[0024] Optionally, the first direction is a horizontal direction, the second direction is a vertical direction, and the second structure waveguide sheet is located on the lower side of the first structure waveguide sheet.

[0025] The present application has the following beneficial effects:

[0026] The optical waveguide device provided by the present application realizes pupil expansion in the first direction and the second direction through the first structure waveguide sheet and the second structure waveguide sheet respectively; compared with the prior art, the first structure waveguide sheet reduces redundant structures and reduces the volume of the optical waveguide device, so that the structure is compact; at the same time, the number of light rays passing through the first beam splitter when reaching the eyebox is reduced, and the light energy utilization rate of the optical waveguide device is improved; at the same time, the volume of the first structure waveguide sheet is compressed, the deviation between the actual position of the human eye and the best position of the human eye is reduced, and the observation position of the human eye is improved. In addition, the angle relationship between the first included angle and the second included angle compensates for the image inversion caused by the included angle of the first structure waveguide sheet, so that the same image display effect as the prior art is maintained.

[0027] The AR device provided by the present application compresses the structure volume, improves the observation position of the human eye, and improves the light energy utilization rate of the optical waveguide device and the use effect by adopting the optical waveguide device. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 A structure diagram of a two-dimensional waveguide sheet of the prior art;

[0029] Figure 2 An internal light path diagram of an upper structure waveguide sheet of the prior art;

[0030] Figure 3 An equivalent light path diagram of a two-dimensional waveguide sheet of the prior art;

[0031] Figure 4 A size diagram of a two-dimensional waveguide sheet of the prior art;

[0032] Figure 5 is a structural schematic diagram of a two-dimensional waveguide sheet provided by the embodiment of the present application.

[0033] In the figure:

[0034] 1', upper structure waveguide sheet; 11', first beam splitter; 12', first surface; 13', second surface; 2', lower structure waveguide sheet; 3', coupling-in structure;

[0035] 1, first structure waveguide sheet; 11, first beam splitter; 12, first glass stack; 13, first substrate;

[0036] 2, second structure waveguide sheet; 21, second beam splitter; 22, second glass stack; 23, second substrate;

[0037] 3, exit pupil of the coupling-in optical engine;

[0038] 4, auxiliary structure. DETAILED DESCRIPTION

[0039] In order to make the technical problems solved by the present application, the technical solutions adopted and the technical effects achieved more clear, the technical solutions of the embodiments of the present application will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0040] In the description of the present application, unless explicitly defined and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0041] In the present application, unless explicitly defined and limited, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "under", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0042] This embodiment provides an optical waveguide device, such as... Figure 5 As shown, the device includes a first structural waveguide 1, a second structural waveguide 2, and an exit pupil 3 for the coupled optical mechanism. Specifically, the first structural waveguide 1 includes two first substrates 13 and a plurality of first beam splitters 11 embedded between the two first substrates 13 and arranged along a first direction. The first beam splitters 11 are arranged at a first angle α with respect to the second direction, where α = 45° - θ. The second structural waveguide 2 includes two second substrates 23 and a plurality of second beam splitters 21 embedded between the two second substrates 23 and arranged along a second direction. The second structural waveguide 2 and the first structural waveguide 1 are arranged along the second direction. The second beam splitters 21 are arranged at a second angle β with respect to the first direction, where β = 45° - θ. The exit pupil 3 for the coupled optical mechanism is arranged at a third angle θ with respect to the second direction. In this embodiment, the first direction is the x-direction, the second direction is the y-direction, and the first direction is perpendicular to the second direction.

[0043] The first structural waveguide 1 and the second structural waveguide 2 respectively achieve pupil expansion in the first and second directions; by setting the exit pupil 3 of the coupled optical engine to form a third angle with the second direction, the first structural waveguide 1 is equivalent to the existing technology such as Figure 3 The structure shown is located within the boundary ray, thereby enabling light transmission, which reduces [the amount of light transmitted] compared to existing technologies. Figure 3 The redundant structure beyond the boundary rays shown reduces the volume of the optical waveguide device, making the structure more compact. Simultaneously, it reduces the number of rays passing through the first beam splitter 11 when reaching the eye box, improving the light energy utilization of the optical waveguide device. Furthermore, it compresses the volume of the first structural waveguide 1, reducing the deviation between the actual and optimal positions of the human eye, thus improving the eye's observation position. In addition, the angular relationship between the first and second included angles compensates for the image flip caused by the included angle of the first structural waveguide 1, maintaining the same image display effect as existing technologies.

[0044] Specifically, the third included angle can be determined according to existing technology. When the optical waveguide device is used in AR glasses, it can be set according to the shape and position of the temple. Optionally, 0≤θ≤45°.

[0045] In this embodiment, θ = 15.36°, the equivalent size of the first structural waveguide is L1 = 75.54 mm; L2 = 17.95 mm, and according to the total internal reflection critical angle formula, the actual size of the first structural waveguide is 57.86 mm × 13.74 mm; the equivalent size of the second structural waveguide is L3 = 34.83 mm.

[0046] like Figure 5As shown, the first beam splitter 11 and the second beam splitter 21 are different in the direction of inclination, the first beam splitter 11 is perpendicular to the first substrate 13 and is arranged at an angle with the second direction, and the second beam splitter 21 is at an angle with the second substrate 23 and is arranged at an angle with the second direction. Optionally, the angle between the second beam splitter 21 and the second substrate 23 is 20-30°, the smaller the angle, the farther the distance between the ghost image and the main image, the better the display image effect, and the larger the angle, the larger the transmission field of view.

[0047] Optionally, as shown in the first structure waveguide sheet 1 includes a plurality of first glass stacks 12 sequentially bonded along the first direction, and the bonding surfaces of the adjacent two first glass stacks 12 form the first beam splitter 11, which is simple in structure and convenient to manufacture. Figure 5 As shown, the first beam splitter 11 and the second beam splitter 21 are different in the direction of inclination, the first beam splitter 11 is perpendicular to the first substrate 13 and is arranged at an angle with the second direction, and the second beam splitter 21 is at an angle with the second substrate 23 and is arranged at an angle with the second direction. Optionally, the angle between the second beam splitter 21 and the second substrate 23 is 20-30°, the smaller the angle, the farther the distance between the ghost image and the main image, the better the display image effect, and the larger the angle, the larger the transmission field of view.

[0048] Optionally, as shown in the first structure waveguide sheet 1 includes a plurality of first glass stacks 12 sequentially bonded along the first direction, and the bonding surfaces of the adjacent two first glass stacks 12 form the first beam splitter 11, which is simple in structure and convenient to manufacture. Figure 5 As shown, the first beam splitter 11 and the second beam splitter 21 are different in the direction of inclination, the first beam splitter 11 is perpendicular to the first substrate 13 and is arranged at an angle with the second direction, and the second beam splitter 21 is at an angle with the second substrate 23 and is arranged at an angle with the second direction. Optionally, the angle between the second beam splitter 21 and the second substrate 23 is 20-30°, the smaller the angle, the farther the distance between the ghost image and the main image, the better the display image effect, and the larger the angle, the larger the transmission field of view. Figure 5 As shown, the first beam splitter 11 and the second beam splitter 21 are different in the direction of inclination, the first beam splitter 11 is perpendicular to the first substrate 13 and is arranged at an angle with the second direction, and the second beam splitter 21 is at an angle with the second substrate 23 and is arranged at an angle with the second direction. Optionally, the angle between the second beam splitter 21 and the second substrate 23 is 20-30°, the smaller the angle, the farther the distance between the ghost image and the main image, the better the display image effect, and the larger the angle, the larger the transmission field of view.

[0049] Further specifically, the plurality of first glass stacks 12 are arranged in parallel to ensure that the two surfaces for gluing are arranged in parallel to ensure that different first beam splitters 11 are parallel to each other, thereby avoiding the generation of ghost images in the display image; similarly, the plurality of second glass stacks 22 are arranged in parallel to ensure that the two surfaces for gluing are arranged in parallel to ensure that different second beam splitters 21 are parallel to each other, thereby avoiding the generation of ghost images in the display image.

[0050] Optionally, the thicknesses of the plurality of first glass stacks 12 along the first direction are all the same, so that different first glass stacks 12 can be used during manufacturing, which is more convenient. The thicknesses of the plurality of second glass stacks 22 along the second direction are all the same, so that different second glass stacks 22 can be used during manufacturing, which is more convenient.

[0051] Optionally, the first substrate 13 and the second substrate 23 on one side are made of the same substrate, and the first substrate 13 and the second substrate 23 on the other side are made of the same substrate, which is convenient for processing and ensures that the first substrate 13 and the second substrate 23 on the same side are in the same plane, and the first substrate 13 and the second substrate 23 on the other side are in the same plane.

[0052] Optionally, the optical waveguide device further comprises an auxiliary structure 4 arranged on both sides of the first structure waveguide sheet 1 along the first direction, for the first structure waveguide sheet 1 to form a corresponding shape, improve the appearance, and can include the first structure waveguide sheet 1 structure, improve the structural stability.

[0053] Optionally, the auxiliary structure 4 comprises two third substrates and an auxiliary glass stack embedded between the two third substrates, the first substrate 13 on one side and the third substrate are made of the same substrate, and the first substrate 13 on the other side and the third substrate are made of the same substrate, facilitating processing. Specifically, the optical waveguide device comprises two substrates and a first glass stack 12, a second glass stack 22 and an auxiliary glass stack embedded between the two substrates.

[0054] The embodiment also provides an AR device comprising the optical waveguide device described above, which realizes pupil expansion in the first direction and the second direction through the first structure waveguide sheet 1 and the second structure waveguide sheet 2 respectively; by setting the exit pupil of the coupling-in light machine to form a third included angle with the second direction, the first structure waveguide sheet 1 is equivalent to the structure inside the boundary ray in the prior art as shown in Figure 3 , so as to realize light transmission, which reduces the redundant structure outside the boundary ray as shown in Figure 3 , thereby reducing the volume of the optical waveguide device; at the same time, the number of light rays passing through the first beam splitter 11 when reaching the eyebox is reduced, improving the light energy utilization rate of the optical waveguide device; at the same time, the volume of the first structure waveguide sheet 1 is compressed, reducing the deviation between the actual position of the human eye and the best position of the human eye, and improving the observation position of the human eye. In addition, the angle relationship between the first included angle and the second included angle compensates for the image flipping caused by the included angle of the first structure waveguide sheet 1, so that the same image display effect as the prior art is maintained.

[0055] For AR glasses and other AR devices, the horizontal eyebox distance is increased to meet the needs of more users, and the vertical eyebox distance adopts a general standard to meet the needs of users. Optionally, the first direction is the horizontal direction, the second direction is the vertical direction, and the second structure waveguide sheet 2 is located below the first structure waveguide sheet 1, which reduces the structural volume of the first structure waveguide sheet 1 relative to the prior art, making the optical waveguide device more compact, and a larger number of replicated pupils can be obtained to meet the needs of different users. The second structure waveguide sheet 2 adopts the structure in the prior art to meet the needs, i.e. a smaller number of second beam splitters 21, which can meet the needs of users for the number of replicated pupils.

[0056] Obviously, the above embodiments of the present application are merely example for clearly explaining the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and also impossible to enumerate all the embodiments. Any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. An optical waveguide device, characterized by, The application relates to an optical waveguide device. The first structure waveguide sheet (1) comprises two first substrates (13) and a plurality of first beam splitters (11) arranged along a first direction and embedded between the two first substrates (13), the first beam splitters (11) are arranged at a first included angle with a second direction, and the first included angle is alpha, wherein alpha=45 DEG -theta; The second structure waveguide sheet (2) comprises two second substrates (23) and a plurality of second beam splitters (21) arranged along a second direction and embedded between the two second substrates (23), the second structure waveguide sheet (2) is arranged along the second direction with the first structure waveguide sheet (1), the second beam splitters (21) are arranged at a second included angle with the first direction, and the second included angle is beta, wherein beta=45 DEG -theta; The first direction is a horizontal direction, and the second direction is a vertical direction; An exit pupil (3) of the in-coupling light machine is arranged at a third included angle with the second direction, the third included angle is theta, and the third included angle theta is: 0<=theta<=45 DEG; The angle relationship between the first included angle and the second included angle can compensate for the image flip caused by the included angle of the first structure waveguide sheet 1.

2. The optical waveguide device of claim 1, wherein, The plurality of first beam splitters (11) are arranged in parallel and at intervals, and the plurality of second beam splitters (21) are arranged in parallel and at intervals.

3. The optical waveguide device according to claim 1, wherein The first structure waveguide sheet (1) comprises a plurality of first glass stacks (12) sequentially bonded along the first direction, and bonding surfaces of two adjacent first glass stacks (12) form the first beam splitter (11); The second structure waveguide sheet (2) comprises a plurality of second glass stacks (22) sequentially bonded along the second direction, and bonding surfaces of two adjacent second glass stacks (22) form the second beam splitter (21).

4. The optical waveguide device of claim 3, wherein, The thicknesses of the plurality of first glass stacks (12) along the first direction are all the same, and the thicknesses of the plurality of second glass stacks (22) along the second direction are all the same.

5. The optical waveguide device of claim 3, wherein, The plurality of first glass stacks (12) are arranged in parallel, and the plurality of second glass stacks (22) are arranged in parallel.

6. The optical waveguide device of claim 1, wherein, The first substrate (13) on one side and the second substrate (23) are made of the same substrate, and the first substrate (13) on the other side and the second substrate (23) are made of the same substrate.

7. The optical waveguide device of claim 6, wherein, The optical waveguide device further comprises an auxiliary structure (4), and the auxiliary structure (4) is arranged on both sides of the first structure waveguide sheet (1) along the first direction.

8. The optical waveguide device of claim 7, wherein, The auxiliary structure (4) comprises two third substrates and auxiliary glass stacks embedded between the two third substrates, the first substrate (13) on one side and the third substrate are made of the same substrate, and the first substrate (13) on the other side and the third substrate are made of the same substrate.

9. An AR device, comprising: The optical waveguide device comprises the optical waveguide device according to any one of claims 1-8.

10. The AR device of claim 9, wherein, The first direction is a horizontal direction, the second direction is a vertical direction, and the second structure waveguide sheet (2) is located on the lower side of the first structure waveguide sheet (1).

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