Diffractive optical waveguide device and augmented reality device

Abstract

The utility model provides a diffractive optical waveguide device and augmented reality equipment, which can improve color uniformity to a certain extent and ensure the efficiency of optical waveguide. The diffractive optical waveguide device includes: a waveguide substrate; the coupling-in unit is provided with a first coupling-in light path and a second coupling-in light path which are separated from each other, and is used for dividing the image light into two paths and coupling the image light into the waveguide substrate so as to propagate along the first coupling-in light path and the second coupling-in light path respectively; the turning unit is arranged on the waveguide substrate and comprises a first turning grating and a second turning grating which are located in the first coupling-in light path and the second coupling-in light path respectively, and the first turning grating and the second turning grating are both one-dimensional turning gratings; the coupling-out unit is arranged on the waveguide substrate and comprises a first coupling-out grating corresponding to the first turning grating and a second coupling-out grating corresponding to the second turning grating, and the first coupling-out grating and the second coupling-out grating are two-dimensional coupling-out gratings which are not overlapped with each other; the grating period of the first out-coupling grating is different from the grating period of the second out-coupling grating.

Description

Technical Field

[0001] The utility model relates to the technical field of diffraction waveguides, in particular to a diffraction optical waveguide device and augmented reality equipment. Background Art

[0002] The diffraction waveguide solution is recognized by the industry as the most important technical path in AR (Augmented Reality) optical display. It provides advantages for augmented reality devices such as lightness and thinness, and appearance close to conventional glasses. Since the diffraction waveguide solution uses the diffraction of the grating to achieve the turning of the entire light path, its diffraction effect will also cause relatively large dispersion of light in different bands, resulting in poor color uniformity. The current common solution to this problem is to use two or three layers of optical waveguides to transmit light in different bands respectively to correct chromatic aberration, but this also brings disadvantages such as thick thickness and heavy weight; therefore, the solution of using a single full-color optical waveguide to solve color uniformity and weight has become an important demand for diffraction waveguides.

[0003] At present, the existing solutions for improving color uniformity of monolithic optical waveguides are either to use the high-order diffraction of the grating to make light of different wavelengths propagate in different orders to achieve the purpose of achromatic aberration, or to use the solution of superposition of single-layer double-sided or single-layer double K-domain channels to achieve the purpose of improving color uniformity. However, for the monolithic full-color optical waveguide solution that transmits different wavelengths in high-order orders separately, not only is it difficult to meet the general efficiency requirements of the waveguide due to the continuous differentiation of efficiency of different orders during the transmission process, but also the mutual interference between multiple orders of diffraction will produce serious ghost images, resulting in the difficulty of the filter process for angle response, which is not practical; for the monolithic full-color optical waveguide solution with multiple K-domain channels, while sacrificing great efficiency, a large number of ghost images are formed due to the high overlap of different K-vector coupling grating areas to produce a large number of coupled lights that do not belong to the target coupling solution. Utility Model Content

[0004] One advantage of the present invention is that it provides a diffractive optical waveguide device and an augmented reality device, which can improve color uniformity to a certain extent while ensuring the efficiency of the optical waveguide.

[0005] Another advantage of the present invention is that it provides a diffractive optical waveguide device and an augmented reality device. In one embodiment of the present invention, the diffractive optical waveguide device can separate two K-domain distributed light bands for transmission and outcoupling respectively, so as to ensure that the two K-domain distributed lights that are respectively beneficial to the transmission of blue light and red light are independently transmitted, thereby facilitating the reduction of ghost images.

[0006] Another advantage of the present invention is that it provides a diffractive optical waveguide device and an augmented reality device. In one embodiment of the present invention, the diffractive optical waveguide device can introduce a one-dimensional turning grating to share the two-dimensional pupil expansion effect of the first half of light transmission, so as to ensure the separation of the light paths of the two half-zones while avoiding the unnecessary outcoupling caused by the premature introduction of the two-dimensional grating, so as to improve the efficiency of the optical waveguide.

[0007] Another advantage of the present invention is that it provides a diffractive optical waveguide device and an augmented reality device. In one embodiment of the present invention, the diffractive optical waveguide device can not only achieve the two half-regions to preferentially transmit blue light and red light respectively to improve the color uniformity of the single chip, but also can specifically reduce the ghost image problem caused by the high overlap of the two K domains of the conventional full-color optical waveguide.

[0008] Another advantage of the present invention is to provide a diffractive optical waveguide device and an augmented reality device, wherein in order to achieve the above-mentioned purpose, no expensive materials or complicated structures are required in the present invention. Therefore, the present invention successfully and effectively provides a solution, not only providing a simple diffractive optical waveguide device and an augmented reality device, but also increasing the practicality and reliability of the diffractive optical waveguide device and the augmented reality device.

[0009] In order to achieve at least one of the above advantages or other advantages and purposes of the utility model, the utility model provides a diffractive optical waveguide device, including:

[0010] waveguide substrate;

[0011] A coupling unit, having a first coupling optical path and a second coupling optical path separated from each other, for coupling the image light into the waveguide substrate in two paths, so as to propagate along the first coupling optical path and the second coupling optical path respectively;

[0012] a turning unit, comprising a first turning grating disposed on the waveguide substrate and located in the first coupling-in optical path, and a second turning grating disposed on the waveguide substrate and located in the second coupling-in optical path, wherein both the first turning grating and the second turning grating are one-dimensional turning gratings; and

[0013] The outcoupling unit comprises a first outcoupling grating arranged on the waveguide substrate and corresponding to the first turning grating and a second outcoupling grating arranged on the waveguide substrate and corresponding to the second turning grating, wherein the first outcoupling grating and the second outcoupling grating are two-dimensional outcoupling gratings that do not overlap each other, and the grating period of the first outcoupling grating is different from the grating period of the second outcoupling grating.

[0014] According to one embodiment of the present application, the grating period of the first outcoupling grating ranges from 310 nm to 330 nm; and the grating period of the second outcoupling grating ranges from 410 nm to 430 nm.

[0015] According to one embodiment of the present application, the grating vector modulus length of the first outcoupling grating is greater than the grating vector modulus length of the second outcoupling grating.

[0016] According to one embodiment of the present application, the coupling unit is a two-dimensional coupling grating arranged on the waveguide substrate; the two-dimensional coupling grating has two grating vectors along the first coupling optical path and the second coupling optical path respectively, and the grating vector modulus along the first coupling optical path is greater than the grating vector modulus along the second coupling optical path.

[0017] According to one embodiment of the present application, the two-dimensional coupling-in grating, the first turning grating, the second turning grating, the first coupling-out grating and the second coupling-out grating are all located on the front surface of the waveguide substrate, wherein the first coupling-out grating and the second coupling-out grating are spliced ​​with each other.

[0018] According to an embodiment of the present application, the two-dimensional coupling-in grating, the first coupling-out grating and the second coupling-out grating are all two-dimensional gratings distributed in the shape of missing corners; the first turning grating and the second turning grating are one-dimensional blazed gratings.

[0019] According to one embodiment of the present application, the coupling unit includes a first coupling grating and a second coupling grating arranged on the waveguide substrate; wherein the first coupling grating and the second coupling grating are both one-dimensional coupling gratings, and the first coupling grating has a grating vector along the first coupling optical path, and the second coupling grating has a grating vector along the second coupling optical path.

[0020] According to an embodiment of the present application, the first coupling grating and the second coupling grating are both located on the front surface of the waveguide substrate; or, the first coupling grating and the second coupling grating are respectively located on the front surface or the rear surface of the waveguide substrate.

[0021] According to one embodiment of the present application, the first turning grating and the second turning grating are arranged symmetrically; the angle between the grating vector of the first turning grating and the X-axis is 120°+a+n*180°, where a is the angle between the grating vector of the first outcoupling grating and the X-axis, and n is a positive integer.

[0022] According to an embodiment of the present application, the grating vector of the coupling-in unit, the grating vector of the deflection unit, and the grating vector of the coupling-out unit form a closed equilateral triangle in K space.

[0023] According to another aspect of the present application, the present application further provides an augmented reality device, including:

[0024] Optical machine; and

[0025] Any of the above-mentioned diffraction optical waveguide devices is arranged on the light output side of the optical machine to transmit the image light from the optical machine.

[0026] According to one embodiment of the present application, the augmented reality device further includes a semi-reflective and semi-transparent element and a total reflection element, the semi-reflective and semi-transparent element is tiltedly arranged in the optical path between the optical machine and the first coupling grating of the diffraction optical waveguide device, the total reflection element is arranged on the reflection side of the semi-reflective and semi-transparent element, and the second coupling grating of the diffraction optical waveguide device is located on the reflection side of the total reflection element. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic structural diagram of an augmented reality device according to an embodiment of the present application;

[0028] Figure 2 A first example of a diffractive optical waveguide device in an augmented reality device according to the above embodiment of the present application is shown;

[0029] Figure 3 A schematic diagram of an optical path of a diffractive optical waveguide device according to the first example of the present application is shown;

[0030] Figure 4 A schematic diagram of K-domain distribution of a diffractive optical waveguide device according to the above embodiment of the present application is shown;

[0031] Figure 5 A schematic top view of a two-dimensional grating in a diffractive optical waveguide device according to the above embodiment of the present application is shown;

[0032] Figure 6 A schematic side view of a one-dimensional grating in a diffractive optical waveguide device according to the above embodiment of the present application is shown;

[0033] Figure 7 A schematic diagram showing the vector action of the first outcoupling grating in the diffraction optical waveguide device according to the above embodiment of the present application is shown;

[0034] Figure 8 A schematic diagram showing the vector action of the second outcoupling grating in the diffractive optical waveguide device according to the above embodiment of the present application is shown;

[0035] Fig. 9 A schematic diagram showing a part of the effect of a two-dimensional outcoupling grating on light in a diffractive optical waveguide device according to the above embodiment of the present application;

[0036] Fig.10 A second example of a diffractive optical waveguide device in an augmented reality device according to the above embodiment of the present application is shown;

[0037] Fig.11 A third example of a diffractive optical waveguide device in an augmented reality device according to the above embodiment of the present application is shown;

[0038] Fig.12 The figure is a flowchart of a method for designing an optical waveguide according to an embodiment of the present application.

[0039] Explanation of the main component symbols: 1. Diffractive optical waveguide device; 10. Waveguide substrate; 101. Upper half partition; 102. Lower half partition; 103. Front surface; 104. Back surface; 20. Coupling unit; 201. First coupling optical path; 202. Second coupling optical path; 21. Two-dimensional coupling grating; 22. First coupling grating; 23. Second coupling grating; 30. Turning unit; 300. One-dimensional turning grating; 31. First turning grating; 32. Second turning grating; 40. Decoupling unit; 400. Two-dimensional decoupling grating; 41. First decoupling grating; 42. Second decoupling grating; 2. Optical machine; 3. Semi-reflective and semi-transmissive element; 4. Total reflection element. DETAILED DESCRIPTION

[0040] The following description is used to disclose the utility model so that those skilled in the art can implement the utility model. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the utility model defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the utility model.

[0041] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0042] In the present invention, the term "one" in the claims and the specification should be understood as "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple. Unless it is clearly indicated in the disclosure of the present invention that the number of the element is only one, the term "one" cannot be understood as unique or single, and the term "one" cannot be understood as a limitation on the quantity.

[0043] In the description of the present utility model, it should be understood that "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through a medium. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

[0044] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0045] Considering the existing solutions for improving color uniformity of monolithic optical waveguides, either the high-order diffraction of the grating is used to make light of different wavelengths propagate in different orders to achieve the purpose of achromatism, or the solution of superposition of single-layer double K-domain channels is used to achieve the purpose of improving color uniformity; however, these solutions will generate a large number of ghost images while greatly sacrificing efficiency. In order to solve this problem, the present application creatively proposes a diffraction optical waveguide device and an augmented reality device, which can improve color uniformity to a certain extent while ensuring the efficiency of the optical waveguide.

[0046] Specifically, refer to the accompanying drawings of the specification of this application. Figures 1 to 11According to one embodiment of the present application, an augmented reality device is provided, which may include an optical machine 2 and a diffractive optical waveguide device 1. The diffractive optical waveguide device 1 is arranged on the light output side of the optical machine 2, and is used for transmitting the image light from the optical machine 2 to the human eye for near-eye display, while also allowing the human eye to view the external environment through the diffractive optical waveguide device 1 to obtain an augmented reality experience.

[0047] More specifically, if Figures 1 to 3 As shown, the diffractive optical waveguide device 1 may include a waveguide substrate 10, a coupling unit 20, a turning unit 30, and a coupling unit 40. The coupling unit 20 may have a first coupling optical path 201 and a second coupling optical path 202 separated from each other, for coupling the image light into the waveguide substrate 10 in two paths, so as to propagate along the first coupling optical path 201 and the second coupling optical path 202 respectively. The turning unit 30 may include a first turning grating 31 disposed on the waveguide substrate 10 and located in the first coupling optical path 201, and a second turning grating 32 disposed on the waveguide substrate 10 and located in the second coupling optical path 202, and both the first turning grating 31 and the second turning grating 32 are one-dimensional turning gratings 300. The outcoupling unit 40 may include a first outcoupling grating 41 disposed on the waveguide substrate 10 and corresponding to the first turning grating 31 and a second outcoupling grating 42 disposed on the waveguide substrate 10 and corresponding to the second turning grating 32; the first outcoupling grating 41 and the second outcoupling grating 42 are non-overlapping two-dimensional outcoupling gratings 400, and the grating period of the first outcoupling grating 41 is different from the grating period of the second outcoupling grating 42.

[0048] In this way, Figure 3 As shown, when the optical machine 2 projects the image light, the coupling unit 20 couples the image light into the waveguide substrate 10 in two paths, so as to propagate along the first coupling optical path 201 to the first turning grating 31, and propagate along the second coupling optical path 202 to the second turning grating 32; furthermore, the image light propagating along the first coupling optical path 201 is pupil-dilated and diverted by the first turning grating 31 to propagate independently to the first coupling-out grating 41, and the image light propagating along the second coupling optical path 202 is pupil-dilated and diverted by the second turning grating 32 to propagate independently to the second coupling-out grating 42; finally, the first coupling-out grating 41 separately couples out the image light from the first turning grating 31 with pupil dilation, and the second coupling-out grating 42 separately couples out the image light from the second turning grating 32 with pupil dilation, so that the human eye can simultaneously receive the image light coupled out through the first coupling-out grating 41 and the second coupling-out grating 42 respectively for near-eye display.

[0049] It is worth noting that Figure 2 and Figure 3As shown, since the first outcoupling grating 41 and the second outcoupling grating 42 are two-dimensional outcoupling gratings 400 that do not overlap each other, and the grating period of the first outcoupling grating 41 is different from the grating period of the second outcoupling grating 42, the first outcoupling grating 41 is conducive to transmitting the first band light (such as blue light) that matches the grating period of the first outcoupling grating 41, and the second outcoupling grating 42 is conducive to transmitting the second band light (such as red light) that matches the grating period of the second outcoupling grating 42; furthermore, Figure 4 As shown, the coupling unit 20, the first turning grating 31 and the first coupling-out grating 41 can construct a first closed K-domain in the K-space that is beneficial to the transmission of light in the first wavelength band, and the coupling unit 20, the second turning grating 32 and the second coupling-out grating 42 can construct a second closed K-domain in the K-space that is beneficial to the transmission of light in the second wavelength band, so that the light rays of the two closed K-domains that are beneficial to the transmission of light in different wavelength bands propagate and couple out independently of each other, so as to reduce ghost images.

[0050] In other words, the diffractive optical waveguide device 1 of the present application uses a special arrangement of gratings to first use a one-dimensional turning grating 300 for transition, and then uses a two-dimensional outcoupling grating 400 for pupil expansion and outcoupling, so as to separate the light transmission of the two K-domain distributions, thereby ensuring that the two K-domain distributions that are beneficial to the blue light transmission and the red light transmission are independently transmitted without interfering with each other and are finally coupled out to the human eye by the first outcoupling grating 41 and the second outcoupling grating 42 respectively, so as to reduce ghost images; at the same time, the diffractive optical waveguide device 1 of the present application introduces a one-dimensional turning grating 300 to share the pupil expansion effect of the first half of the light transmission, and avoids unnecessary outcoupling caused by premature introduction of a two-dimensional outcoupling grating while ensuring the separation of the two transmission optical paths, thereby improving the color uniformity to a certain extent and ensuring the efficiency of the optical waveguide.

[0051] Exemplarily, the grating period range of the first outcoupling grating 41 can be implemented as 310nm to 330nm, which is conducive to the transmission of blue light and green light; the grating period range of the second outcoupling grating 42 can be implemented as 410nm to 430nm, which is conducive to the transmission of red light and green light. In this way, the step length of the blue light transmitted through the first outcoupling grating 41 is substantially consistent with the step length of the red light transmitted through the second outcoupling grating 42, and in the transmission condition of the diffraction optical waveguide device 1, the corner cuts of the red light and the blue light are not much, which can improve the color uniformity to a certain extent. It can be understood that in other examples of the present application, the grating period ranges of the first outcoupling grating 41 and the second outcoupling grating 42 can also be interchanged, and this application will not repeat them.

[0052] For the convenience of description and understanding, the waveguide substrate 10 is divided into two partitions according to the up and down direction (ie, the Y-axis direction) when the user wears it. Figure 2 and Figure 3The upper partition 101 and the lower partition 102 are shown; and the surface of the waveguide substrate 10 facing the user (ie, the Z-axis direction) and the surface facing away from the user are positioned as shown in FIG. Figure 1 The front surface 103 and the rear surface 104 are shown. The first turning grating 31 and the first outcoupling grating 41 are both located in the upper half of the waveguide substrate 10, and the second turning grating 32 and the second outcoupling grating 42 are both located in the lower half of the waveguide substrate 10. It can be understood that the X-axis direction of the present application refers to Figure 2 The left and right direction is the arrangement direction of the coupling unit 20 and the coupling unit 40.

[0053] Optionally, the grating vector modulus of the first outcoupling grating 41 is greater than the grating vector modulus of the second outcoupling grating 42, so that the transmission step length of the blue light in the upper partition 101 is consistent with the transmission step length of the red light in the lower partition 102, which is beneficial to improving color uniformity and minimizing ghost images.

[0054] It is worth noting that in the first example of this application, Figures 1 to 3 As shown, the coupling unit 20 is implemented as a two-dimensional coupling grating 21 arranged on the waveguide substrate 10, which is used to transmit the image light coupled into the waveguide substrate 10 to the first turning grating 31 and the second turning grating 32 along two different directions (i.e., the first coupling optical path 201 and the second coupling optical path 202) respectively.

[0055] Alternatively, if Figure 3 As shown, the two-dimensional coupling grating 21 has two grating vectors along the first coupling optical path 201 and the second coupling optical path 202 respectively; and the modulus length of the grating vector along the first coupling optical path 201 is greater than the modulus length of the grating vector along the second coupling optical path 202. In this way, the transmission step length of the blue light in the upper sub-area 101 and the transmission step length of the red light in the lower sub-area 102 can be closer, and finally the blue light emitted from the upper sub-area 101 and the red light emitted from the lower sub-area 102 are basically not offset too much, which further ensures that the color uniformity is improved while reducing the ghost image as much as possible.

[0056] Alternatively, if Figure 2 and Figure 3 As shown, the first turning grating 31 and the second turning grating 32 are basically symmetrically arranged, so that the grating vector direction of the first turning grating 31 is approximately symmetrical with the grating vector direction of the second turning grating 32, so as to receive the image light from the coupling-in unit 20 and transmit the image light from the upper and lower halves of the waveguide substrate 10 to the first outcoupling grating 41 and the second outcoupling grating 42, respectively.

[0057] Alternatively, if Figures 1 to 3As shown, the two-dimensional coupling-in grating 21, the first turning grating 31, the second turning grating 32, the first coupling-out grating 41 and the second coupling-out grating 42 are all located on the front surface 103 of the waveguide substrate 10, wherein the first coupling-out grating 41 and the second coupling-out grating 42 are spliced ​​with each other to completely cover the entire coupling-out region. It can be understood that in other examples of the present application, the first coupling-out grating 41 and the second coupling-out grating 42 can also be located on the front surface 103 and the rear surface 104 of the waveguide substrate 10, respectively, as long as they do not overlap each other in the front-to-back direction and can be spliced ​​with each other, and the present application will not repeat them in detail.

[0058] Optionally, the angle between the grating vector of the first turning grating 31 and the X-axis is 120°+a+n*180°; wherein a is the angle between the grating vector of the first outcoupling grating 41 and the X-axis, and n is a positive integer.

[0059] It is worth noting that the angle a between the grating vector of the first outcoupling grating 41 of the present application and the X-axis is determined by the grating vector component kfy1 of the half field angle in the Y direction of the K-domain space, that is, a min =arcsin(|kyf1| / |kout1|)+180°, and the value range of a is implemented as a min to a min +2°, so as to ensure that a small field of view outcoupling light is formed at the middle joint of the first outcoupling grating 41 and the second outcoupling grating 42.

[0060] Alternatively, if Figure 5 As shown, the two-dimensional coupling-in grating 21 , the first coupling-out grating 41 , and the second coupling-out grating 42 are all implemented as two-dimensional gratings with a prism-shaped distribution of notched corners.

[0061] Alternatively, if Figure 6 As shown, the first turning grating 31 and the second turning grating 32 are both implemented as one-dimensional blazed gratings.

[0062] Alternatively, if Figure 4 As shown, in each closed K domain, the grating vector of the coupling-in unit 20, the grating vector of the turning unit 30 and the grating vector of the coupling-out unit 40 form a closed equilateral triangle in the K space, wherein the grating periods represented by each equilateral triangle are equal, and the closed triangles in the upper and lower half areas both satisfy the K space transmission conditions of the diffraction optical waveguide.

[0063] Optionally, the refractive index of the waveguide substrate 10 is at least greater than 2.0. Preferably, the refractive index of the waveguide substrate 10 can simultaneously satisfy the refractive index of blue light 2.165, the refractive index of green light 2.125, and the refractive index of red light 2.091.

[0064] In summary, in the above-mentioned first example of the present application: when the optical machine 2 projects the image light in the visible light band to the two-dimensional coupling grating 21 located on the front surface 103 of the waveguide substrate 10, under the action of the two grating vectors of the two-dimensional coupling grating 21 along the first coupling optical path 201 and the second coupling optical path 202 respectively, the 0 field of view of the coupled light (i.e., the coupled image light) is transmitted along the first coupling optical path 201 and then the second coupling optical path 202 in the upper partition 101 and the lower partition 102 of the waveguide substrate 10 after entering the waveguide substrate 10, so that the coupled light transmitted in the upper partition 101 and the coupled light transmitted in the lower partition 102 are propagated to the first turning grating 31 and the second turning grating 32 respectively, wherein the grating vectors of the first turning grating 31 are as shown in FIG. Figure 7 In the B direction shown, the grating vector of the second turning grating 32 is as follows Figure 8 A direction as shown; further, after the image light propagating along the first coupling-in optical path 201 and the second coupling-in optical path 202 passes through the grating vectors of the first turning grating 31 and the second turning grating 32, it continues to propagate independently in the upper half partition 101 and the lower half partition 102 of the waveguide substrate 10, so as to be transmitted to the first coupling-out grating 41 and the second coupling-out grating 42, respectively, wherein the grating vector of the first coupling-out grating 41 has the following characteristics: Figure 7 In the A direction and the B direction shown in FIG. 1 , the grating vector of the second outcoupling grating 42 has the following characteristics: Figure 8 The A and B directions are shown.

[0065] It is worth noting that Figure 7 The grating vector in the A direction is used to couple out the image light from the first turning grating 31, and Figure 7 The grating vector in the B direction is used to expand the pupil of the image light from the first turning grating 31 in a two-dimensional direction, that is, to expand the pupil upward; Figure 8 The grating vector in the B direction is used to couple out the image light from the second turning grating 32, and Figure 8 The grating vector in the A direction is used to expand the pupil of the image light from the second turning grating 32 in a two-dimensional direction, that is, to expand the pupil downward.

[0066] In addition, by Figure 7 The first type of line shape change, the second type of line shape change and the third type of line shape change shown in the figure show all iterative lights generated by the two-dimensional grating vector action of the first outcoupling grating 41, wherein Figure 7 The first type of line shape change in means that the direction of the main light a1 (i.e., effective light a1) propagating to the 0 field of view of the first out-coupling grating 41 does not change, and after acting on four K vectors b1-b4 of the two-dimensional grating in different directions, the line shape c11-c14 of the light after diffraction changes; Figure 7The second type of line shape change means that after diffraction in the first type of line shape change, the direction of the effective light a2 changes relative to the direction in the first type of line shape change, but does not change in the second type of line shape change. After the effective light a2 acts on the four K vectors b1-b4 of the two-dimensional grating in different directions, the line shape c21-c24 of the light changes after diffraction. Figure 7 The third type of line shape change means that after diffraction in the second type of line shape change, the direction of the effective light a3 changes relative to the direction in the second type of line shape change, but does not change in the third type of line shape change. After the effective light a3 acts on the four K vectors b1-b4 of the two-dimensional grating in different directions, the line shape of the light c31-c34 changes after diffraction. It can be understood that although Figure 7 It is easy to know that only the light wave vector c12 generated by the left second figure in the first type of linear change is inclined downward, but Fig. 9 It can be seen from the K-space grating vector action diagram that the light wave vector c12 no longer meets the conditions for optical waveguide transmission and diffraction generation in the K domain, that is, this oblique downward light does not exist, and the light in other directions will not be transmitted downward. Therefore, the upper partition 101 of the waveguide substrate 10 of the present application will not have new light transmitted toward the lower partition 102, thereby avoiding the light in the upper partition 101 from interfering with the light in the lower partition 102.

[0067] Similarly, by Figure 8 The first type of line shape change, the second type of line shape change and the third type of line shape change shown in the figure show all the iterative lights generated by the two-dimensional grating vector action of the second outcoupling grating 42, wherein Figure 8 The first type of line shape change in means that the direction of the main light d1 (i.e., effective light d1) of the 0 field of view propagating to the second out-coupling grating 42 does not change, and after acting on the four K vectors e1-e4 of the two-dimensional grating in different directions, the line shape f11-f14 of the light after diffraction changes; Figure 8 The second type of line shape change means that after diffraction in the first type of line shape change, the direction of the effective light d2 changes relative to the direction in the first type of line shape change, but does not change in the second type of line shape change. After the effective light d2 acts on the four K vectors e1-e4 of the two-dimensional grating in different directions, the line shape f21-f24 of the light changes after diffraction. Figure 8 The third type of line shape change means that after diffraction in the second type of line shape change, the direction of the effective light d3 changes relative to the direction in the second type of line shape change, but does not change in the third type of line shape change. After the effective light d3 acts on the four K vectors e1-e4 of the two-dimensional grating in different directions, the line shape f31-f34 of the light changes after diffraction. It can be understood that although Figure 8It is easy to know that only the light wave vector f12 generated in the second left figure in the first type of linear change is obliquely upward, but because the second coupling grating 42 and the first coupling grating 41 are arranged symmetrically, the light wave vector f12 no longer meets the conditions for optical waveguide transmission and diffraction generation in the K domain, that is, this obliquely upward light does not exist, and the light in other directions will not be transmitted upward, so the lower partition 102 of the waveguide substrate 10 of the present application will not have new light transmitted toward the upper partition 101, so as to avoid the light of the lower partition 102 interfering with the light of the upper partition 101; in other words, there is no light crosstalk between the upper partition 101 and the lower partition 102 in the waveguide substrate 10, which ensures that the two K-domain distributed lights that are beneficial to blue light transmission and red light transmission are independently transmitted in the upper partition 101 and the lower partition 102 of the waveguide substrate 10 respectively, so as to effectively reduce ghost images.

[0068] It is worth noting that Fig.10 A second example of an augmented reality device according to the above embodiment of the present application is shown. Compared with the above first example according to the present application, the augmented reality device according to the second example of the present application is different in that: the coupling unit 20 in the diffractive optical waveguide device 1 may include a first coupling grating 22 and a second coupling grating 23 arranged on the waveguide substrate 10, wherein the first coupling grating 22 and the second coupling grating 23 are both one-dimensional coupling gratings, and the first coupling grating 22 has a grating vector along the first coupling optical path 201, which is used to couple the image light into the waveguide substrate 10 to transmit to the first turning grating 31, and the second coupling grating 23 has a grating vector along the second coupling optical path 202, which is used to couple the image light into the waveguide substrate 10 to transmit to the second turning grating 32.

[0069] At the same time, in order to ensure that the image light projected by the optical machine 2 can be transmitted to the first coupling grating 22 and the second coupling grating 23 respectively, as shown in FIG. Fig.10As shown, the augmented reality device may also include a semi-reflective and semi-transmissive element 3 and a total reflection element 4, wherein the semi-reflective and semi-transmissive element 3 is tiltedly arranged in the optical path between the optical machine 2 and the first coupling grating 22, the total reflection element 4 is arranged on the reflection side of the semi-reflective and semi-transmissive element 3, and the second coupling grating 23 is located on the reflection side of the total reflection element 4. In this way, a part of the image light projected through the optical machine 2 will be transmitted by the semi-reflective and semi-transmissive element 3 to propagate to the first coupling grating 22 and be coupled into the waveguide substrate 10 by the first coupling grating 22, while another part of the image light projected through the optical machine 2 will first be reflected by the semi-reflective and semi-transmissive element 3 to propagate to the total reflection element 4, and then reflected by the total reflection element 4 to propagate to the second coupling grating 23 and be coupled into the waveguide substrate 10 by the second coupling grating 23. It can be understood that the semi-reflective and semi-transparent element 3 mentioned in the present application can be implemented as, but not limited to, a semi-reflective and semi-transparent film, a BS prism or a PBS prism; the total reflection element 4 can be implemented as, but not limited to, a plane reflector.

[0070] Optionally, in the second example of the present application, as Fig.10 As shown, the first coupling grating 22 and the second coupling grating 23 are both located on the front surface 103 of the waveguide substrate 10, so that the coupling unit 20 forms a single-sided one-dimensional grating capable of two-dimensional coupling. Of course, in the third example of the present application, as Fig.11 As shown, the first coupling grating 22 and the second coupling grating 23 may also be located on the front surface 103 and the rear surface 104 of the waveguide substrate 10 respectively, so that the coupling unit 20 forms a double-sided one-dimensional grating, which can still play a two-dimensional coupling role.

[0071] It is worth mentioning that according to another aspect of the present application, Fig.12 As shown, an embodiment of the present application further provides an optical waveguide design method, which may include the steps of:

[0072] S100: constructing a first closed K domain in the K space that is beneficial to the transmission of light in the first wavelength band in the upper half of the waveguide substrate; and

[0073] S200: constructing a second closed K domain in the K space in the lower partition of the waveguide substrate for facilitating transmission of a second wavelength band light having a different bandwidth from the first wavelength band light.

[0074] In this way, the first closed K domain and the second closed K domain are respectively and separately located in the upper and lower partitions of the waveguide substrate, so that the optical waveguide design method of the present application can ensure that the light in the two constructed closed K domains can propagate independently, so as to improve color uniformity while minimizing the generation of ghost images.

[0075] Optionally, the first closed K domain and the second closed K domain both include a grating vector of a coupling-in unit, a grating vector of a turning unit, and a grating vector of a coupling-out unit, wherein the grating vector of the coupling-in unit, the grating vector of the turning unit, and the grating vector of the coupling-out unit in each closed K domain form a closed equilateral triangle in the K space. In this way, the grating periods represented by each triangle are equal, and the closed triangles in the upper and lower half areas can meet the K space transmission conditions of the diffraction optical waveguide, which is conducive to rapidly expanding the pupil along the Y direction of the optical waveguide in the two-dimensional pupil expansion part, reducing the area size of the coupling-out area, and reducing the energy coupled out in advance, so as to improve the overall efficiency of the optical waveguide.

[0076] Optionally, the first closed K domain is conducive to the transmission of blue light, and the second closed K domain is conducive to the transmission of red light. The grating vector modulus of the coupling-in unit and the coupling-out unit in the first closed K domain is larger than the grating vector modulus in the second closed K domain, so that the transmission step length of the blue light in the upper half partition is close to the transmission step length of the red light in the lower half partition.

[0077] Optionally, the angle between the out-coupling grating vector located in the upper half partition of the waveguide substrate and the X-axis is between amin and amin+2°, wherein amin=arcsin(|kfy1| / |kout1|)+180°, arcsin represents the inverse sine function; kfy1 represents the out-coupling grating vector; kout1 represents the grating vector component of the half-viewing angle on the Y-axis of the K-domain space. It can be understood that the angle a between the out-coupling grating vector kout1 of the upper half partition of the present application and the X-axis is determined by the grating vector component kfy1 of the half-viewing angle in the Y direction of the K-domain space, and when the angle a is within a min and a min When the angle is between +2°, the light outcoupling in the small field of view at the middle joint of the outcoupling grating can be guaranteed.

[0078] Optionally, the angle between the grating vector of the coupling unit and the X-axis is a+60°, where a is the angle between the coupling grating vector of the upper half partition and the X-axis. In this way, the pupil is rapidly expanded along the Y direction of the optical waveguide in the two-dimensional pupil expansion part, which can not only reduce the area size of the coupling area, but also reduce the energy of premature coupling, which helps to improve the overall efficiency of the optical waveguide.

[0079] Optionally, the K-vectors located in the upper half of the waveguide substrate are distributed symmetrically with respect to the X-axis with respect to the K-vectors located in the lower half of the waveguide substrate, so that the optical path transmission in the upper and lower halves is approximately symmetrical, so that they can be transmitted independently in the upper and lower halves respectively in accordance with their respective K-domain principles, and the shapes of the grating regions in the upper and lower halves established by the design method are symmetrically distributed.

[0080] In summary, the optical waveguide design method of the present application can not only achieve the purpose of preferentially transmitting blue light and red light in the upper and lower halves respectively to improve the color uniformity of the single chip through the construction of double K domains in the upper and lower halves, but also can specifically reduce the ghost image problem that is very easy to occur due to the front and back overlap of the K domain areas in the conventional single chip color uniformity dual K domain solution.

[0081] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0082] The above embodiments only express several implementation methods of the utility model, and the descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model.

Claims

1. A diffractive optical waveguide device, characterized in that: include: waveguide substrate; A coupling unit, having a first coupling optical path and a second coupling optical path separated from each other, for coupling the image light into the waveguide substrate in two paths, so as to propagate along the first coupling optical path and the second coupling optical path respectively; a turning unit, comprising a first turning grating disposed on the waveguide substrate and located in the first coupling-in optical path, and a second turning grating disposed on the waveguide substrate and located in the second coupling-in optical path, wherein both the first turning grating and the second turning grating are one-dimensional turning gratings; and The outcoupling unit comprises a first outcoupling grating arranged on the waveguide substrate and corresponding to the first turning grating and a second outcoupling grating arranged on the waveguide substrate and corresponding to the second turning grating, wherein the first outcoupling grating and the second outcoupling grating are two-dimensional outcoupling gratings that do not overlap each other, and the grating period of the first outcoupling grating is different from the grating period of the second outcoupling grating.

2. The diffractive optical waveguide device according to claim 1, characterized in that: The grating period of the first outcoupling grating ranges from 310 nm to 330 nm; the grating period of the second outcoupling grating ranges from 410 nm to 430 nm.

3. The diffractive optical waveguide device according to claim 2, characterized in that: The grating vector modulus length of the first outcoupling grating is greater than the grating vector modulus length of the second outcoupling grating.

4. The diffractive optical waveguide device according to any one of claims 1 to 3, characterized in that: The coupling unit is a two-dimensional coupling grating arranged on the waveguide substrate; the two-dimensional coupling grating has two grating vectors along the first coupling optical path and the second coupling optical path respectively, and the grating vector modulus along the first coupling optical path is greater than the grating vector modulus along the second coupling optical path.

5. The diffractive optical waveguide device according to claim 4, characterized in that: The two-dimensional coupling-in grating, the first turning grating, the second turning grating, the first coupling-out grating and the second coupling-out grating are all located on the front surface of the waveguide substrate, wherein the first coupling-out grating and the second coupling-out grating are spliced ​​with each other.

6. The diffractive optical waveguide device according to claim 4, characterized in that: The two-dimensional coupling-in grating, the first coupling-out grating and the second coupling-out grating are all two-dimensional gratings distributed in the shape of missing corners; the first turning grating and the second turning grating are one-dimensional blazed gratings.

7. The diffractive optical waveguide device according to any one of claims 1 to 3, characterized in that: The coupling unit includes a first coupling grating and a second coupling grating arranged on the waveguide substrate; wherein the first coupling grating and the second coupling grating are both one-dimensional coupling gratings, and the first coupling grating has a grating vector along the first coupling optical path, and the second coupling grating has a grating vector along the second coupling optical path.

8. The diffractive optical waveguide device according to claim 7, characterized in that: The first coupling-in grating and the second coupling-in grating are both located on the front surface of the waveguide substrate; or, the first coupling-in grating and the second coupling-in grating are respectively located on the front surface or the rear surface of the waveguide substrate.

9. The diffractive optical waveguide device according to any one of claims 1 to 3, characterized in that: The first turning grating and the second turning grating are arranged symmetrically; the angle between the grating vector of the first turning grating and the X-axis is 120°+a+n*180°, where a is the angle between the grating vector of the first outcoupling grating and the X-axis, and n is a positive integer.

10. The diffractive optical waveguide device according to any one of claims 1 to 3, characterized in that: The grating vector of the coupling-in unit, the grating vector of the deflection unit, and the grating vector of the coupling-out unit form a closed equilateral triangle in K-space.

11. An augmented reality device, characterized in that include: Optical machine; and The diffraction optical waveguide device as described in any one of claims 1 to 10 is arranged on the light output side of the optical machine and is used to transmit the image light from the optical machine.

12. The augmented reality device according to claim 11, characterized in that It also includes a semi-reflective and semi-transparent element and a total reflection element, wherein the semi-reflective and semi-transparent element is tiltedly arranged in the light path between the optical machine and the first coupling grating of the diffraction optical waveguide device, the total reflection element is arranged on the reflection side of the semi-reflective and semi-transparent element, and the second coupling grating of the diffraction optical waveguide device is located on the reflection side of the total reflection element.

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