Grating waveguide and near-eye display system

Abstract

The utility model is applicable to the technical field of grating waveguides, and provides a grating waveguide and a near-to-eye display system, a coupling-in element, a first polarization reflection device, a coupling-out element and a second polarization reflection device are sequentially arranged on a waveguide base body at intervals, so that external first polarization light rays enter the waveguide base body through the coupling-in element to be transmitted; the light passes through the coupling-out element for four times to form four coupled-out light and four non-coupled-out light, the four coupled-out light is emitted out of the waveguide substrate to be projected to the eyes of a user, the diffraction efficiency of the coupled-out light is effectively improved, the first three non-coupled-out light continues to be propagated in the waveguide substrate, and the diffraction efficiency of the coupled-out light is effectively improved. Only the fourth non-coupled light is leaked from one side of the waveguide substrate, so that the diffraction efficiency of the non-coupled light is improved, the leakage proportion of the non-coupled light is reduced, and the diffraction efficiency of the grating waveguide is improved on the whole.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of near-eye display (NED), and particularly relates to a grating waveguide and a near-eye display system. BACKGROUND

[0002] In the near-eye display technology, the grating waveguide is a key optical element, which is widely used in augmented reality (AR) devices, virtual reality (VR) devices and mixed reality (MR). The image emitted by the opto-mechanical system enters the waveguide substrate through the coupling-in element, propagates in the waveguide substrate through total internal reflection (TIR), and is projected to the user's eyes through the coupling-out element. The diffraction efficiency of the grating waveguide is a key factor to determine the imaging quality of the image in the user's eyes. CONTENT OF THE UTILITY MODEL

[0003] Therefore, the embodiments of the present application provide a grating waveguide and a near-eye display system, which can effectively improve the diffraction efficiency of the grating waveguide, thereby improving the imaging quality of the near-eye display system based on the grating waveguide.

[0004] The first aspect of the embodiments of the present application provides a grating waveguide, comprising a waveguide substrate, and a coupling-in element, a first polarization reflection device, a coupling-out element and a second polarization reflection device which are sequentially and spacedly arranged on the waveguide substrate.

[0005] The first polarized light from outside enters the waveguide substrate through the coupling-in element, and is reflected to the coupling-out element through the first polarization reflection device, and then diffracted by the coupling-out element to form first coupling-out light and first non-coupling-out light.

[0006] The first non-coupling-out light propagates to the second polarization reflection device through the waveguide substrate, and is reflected and the polarization direction is changed by the second polarization reflection device to form second polarized light.

[0007] The second polarized light propagates to the coupling-out element through the waveguide substrate, and is diffracted by the coupling-out element to form second coupling-out light and second non-coupling-out light.

[0008] The second non-coupling-out light propagates to the first polarization reflection device through the waveguide substrate, is reflected by the first polarization reflection device in the original path to the coupling-out element, and is diffracted by the coupling-out element to form third coupling-out light and third non-coupling-out light;

[0009] The third non-coupling-out light propagates to the second polarization reflection device through the waveguide substrate, is reflected by the second polarization reflection device and changes the polarization direction to form third polarization light;

[0010] The third polarization light propagates to the coupling-out element through the waveguide substrate, and is diffracted by the coupling-out element to form fourth coupling-out light and fourth non-coupling-out light;

[0011] The fourth non-coupling-out light is reflected by the first polarization reflection device and propagates to the side of the waveguide substrate away from the second polarization reflection device.

[0012] The first aspect of the embodiment of the present application arranges the coupling-in element, the first polarization reflection device, the coupling-out element and the second polarization reflection device in the waveguide substrate in sequence, so that the external first polarization light enters the waveguide substrate through the coupling-in element and propagates in the waveguide substrate, and the light passes through the coupling-out element four times to form four times of coupling-out light and four times of non-coupling-out light, wherein the four times of coupling-out light are emitted from the waveguide substrate to be projected to the user's eyes, the diffraction efficiency of the coupling-out light is effectively improved, the first three times of non-coupling-out light continue to propagate in the waveguide substrate, and only the fourth time of non-coupling-out light leaks from one side of the waveguide substrate, the diffraction efficiency of the non-coupling-out light is improved, the leakage ratio of the non-coupling-out light is reduced, and the diffraction efficiency of the grating waveguide is improved as a whole.

[0013] In one embodiment, the waveguide substrate includes a first surface, a second surface, a third surface and a fourth surface, the first surface and the second surface are oppositely arranged, and the third surface and the fourth surface are oppositely arranged and respectively connected to the first surface and the second surface;

[0014] The coupling-in element is arranged on the first surface;

[0015] At least one of the first polarization reflection device and the coupling-out element is arranged on the first surface or the second surface;

[0016] The second polarization reflection device is arranged inside the waveguide substrate and connected to the first surface and the second surface, or the second polarization reflection device is arranged on the third surface;

[0017] The fourth non-coupling-out light is emitted from the fourth surface.

[0018] The embodiments of the present application provide various schemes of arranging the coupling-in element, the first polarization reflection device, the coupling-out element and the second polarization reflection device on the waveguide substrate, thereby improving the flexibility of the preparation process of the grating waveguide; the coupling-in element, the first polarization reflection device and the coupling-out element are arranged on the surface of the waveguide substrate, so that the coupling-in element, the first polarization reflection device and the coupling-out element can be prepared separately and then arranged on the waveguide substrate, thereby simplifying the preparation process of the grating waveguide.

[0019] In one embodiment, the coupling-in element, the first polarization reflection device and the coupling-out element are arranged on the first surface.

[0020] The embodiments of the present application arrange the coupling-in element, the first polarization reflection device and the coupling-out element on the same surface of the waveguide substrate, so that the coupling-in element, the first polarization reflection device and the coupling-out element can be arranged in batches, thereby further simplifying the preparation process of the grating waveguide.

[0021] In one embodiment, the second polarization reflection device is arranged on the third surface.

[0022] The embodiments of the present application arrange the second polarization reflection device on the surface of the waveguide substrate, so that the second polarization reflection device can be prepared separately and then arranged on the surface of the waveguide substrate, thereby simplifying the preparation process of the grating waveguide.

[0023] In one embodiment, the first polarization reflection device comprises a first reflection element and a plurality of first polarization reflection elements, the plurality of first polarization reflection elements are spaced apart and parallel to each other, arranged between the first reflection element and the waveguide substrate, and inclined at a specific angle relative to the first reflection element.

[0024] The first polarized light is reflected by the first reflection element and transmitted to the coupling-out element through the plurality of first polarization reflection elements;

[0025] The second non-coupling-out light is reflected to the coupling-out element through the plurality of first polarization reflection elements in the original path;

[0026] The fourth non-coupling-out light is transmitted to the first reflection element through the plurality of first polarization reflection elements, and reflected to the waveguide substrate by the first reflection element.

[0027] The embodiments of the present application construct the first polarization reflection device by the first reflection element and the plurality of first polarization reflection elements, and arrange the first polarization reflection elements to be inclined at a specific angle relative to the first reflection element, so that the incident light can return in the original path, thereby simplifying the structure and facilitating the implementation.

[0028] In one embodiment, the first polarization reflecting device further comprises a plurality of first light-transmitting supporting elements disposed between the first reflecting element, the plurality of first polarization reflecting elements and the waveguide substrate.

[0029] The first polarization reflecting device is formed by the first reflecting element, the plurality of first polarization reflecting elements and the plurality of first light-transmitting supporting elements, so that the first polarization reflecting device can be prepared by stacking a plurality of first light-transmitting supporting element substrates, inserting a layer of first polarization reflecting elements between adjacent first light-transmitting supporting element substrates, cutting and attaching a layer of first reflecting elements at a specific angle, which is simple in preparation process and easy to implement.

[0030] In one embodiment, the first polarization reflecting device comprises a second polarization reflecting element and a plurality of second reflecting elements, the second polarization reflecting element is disposed between the plurality of second reflecting elements and the waveguide substrate, and the plurality of second reflecting elements are spaced apart from each other, parallel and inclined at a specific angle relative to the second polarization reflecting element.

[0031] The first polarized light is reflected by the second polarization reflecting element to the out-coupling element.

[0032] The second non-coupling-out light is transmitted by the second polarization reflecting element to the plurality of second reflecting elements, and is reflected by the plurality of second reflecting elements to the second polarization reflecting element in the original path, and is transmitted by the second polarization reflecting element to the out-coupling element.

[0033] The fourth non-coupling-out light is reflected by the second polarization reflecting element to the waveguide substrate.

[0034] The first polarization reflecting device is formed by the second polarization reflecting element and the plurality of second reflecting elements, so that the second reflecting elements are disposed at a specific angle relative to the second polarization reflecting element, so that the incident light can return in the original path, which is simple in structure and easy to implement.

[0035] In one embodiment, the first polarization reflecting device further comprises a second light-transmitting supporting element disposed between the second polarization reflecting element and the plurality of second reflecting elements.

[0036] The first polarization reflecting device is formed by the second polarization reflecting element, the plurality of second reflecting elements and the second light-transmitting supporting element, so that the first polarization reflecting device can be prepared by cutting one side of the second light-transmitting supporting element substrate at a specific angle to form a plurality of sawtooth structures, attaching a layer of second reflecting elements on the surface of each sawtooth structure, and attaching a layer of second polarization reflecting elements on the opposite side, which is simple in preparation process and easy to implement.

[0037] In one embodiment, the second polarization reflection device comprises a 1 / 4 wave plate and a third reflective element, and the third reflective element is arranged on the side of the 1 / 4 wave plate away from the out-coupling element.

[0038] The second polarization reflection device is composed of the 1 / 4 wave plate and the third reflective element, so that the second polarization reflection device can reflect and convert the polarization direction of the incident light, and the structure is simple and easy to implement.

[0039] The second aspect of the embodiment of the present application provides a near-eye display system, which comprises an optical engine and the grating waveguide provided by the first aspect of the embodiment of the present application, and the first polarized light is emitted by the optical engine to the in-coupling element.

[0040] The second aspect of the embodiment of the present application realizes the near-eye display system based on the grating waveguide of the first aspect, and improves the imaging quality of the near-eye display system. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0042] Figure 1 is a first structure schematic diagram of the grating waveguide provided by the embodiment of the present application;

[0043] Figure 2 is a second structure schematic diagram of the grating waveguide provided by the embodiment of the present application;

[0044] Figure 3 is a third structure schematic diagram of the grating waveguide provided by the embodiment of the present application;

[0045] Figure 4 is a fourth structure schematic diagram of the grating waveguide provided by the embodiment of the present application;

[0046] Figure 5 is a first structure schematic diagram of the first polarization reflection device provided by the embodiment of the present application;

[0047] Figure 6 is a second structure schematic diagram of the first polarization reflection device provided by the embodiment of the present application;

[0048] Figure 7 is a first preparation flow schematic diagram of the first polarization reflection device provided by the embodiment of the present application;

[0049] Figure 8Fig. 3 is a third structural schematic diagram of a first polarization reflection device provided in an embodiment of the present application;

[0050] Figure 9 Fig. 4 is a fourth structural schematic diagram of a first polarization reflection device provided in an embodiment of the present application;

[0051] Figure 10 Fig. 5 is a second preparation flow schematic diagram of a first polarization reflection device provided in an embodiment of the present application;

[0052] Figure 11 Fig. 6 is a structural schematic diagram of a second polarization reflection device provided in an embodiment of the present application;

[0053] Figure 12 Fig. 7 is a structural schematic diagram of a near-eye display system provided in an embodiment of the present application;

[0054] Reference Signs:

[0055] Grating waveguide-100, first polarized light-101, first out-coupled light-102, first non-coupled light-103, second polarized light-104, second out-coupled light-105, second non-coupled light-106, third out-coupled light-107, third non-coupled light-108, third polarized light-109, fourth out-coupled light-110, fourth non-coupled light-111;

[0056] Waveguide base body-10, first surface-11, second surface-12, third surface-13, fourth surface-14;

[0057] In-coupling element-20;

[0058] First polarization reflection device-30, first reflection element-31, first polarization reflection element-32, first light-transmitting support element-33, first light-transmitting support element base-34, first preliminary body-301, second preliminary body-302, third preliminary body-303, second polarization reflection element-35, multiple second reflection elements-36, second light-transmitting support element-37, second light-transmitting support element base-38;

[0059] Out-coupling element-40;

[0060] Second polarization reflection device-50, 1 / 4 wave plate-51, third reflection element-52;

[0061] Near-eye display system-1000;

[0062] Optomechanics-200. DETAILED DESCRIPTION

[0063] In order to better understand the present application, the following will be combined with the accompanying drawings of the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of the present application.

[0064] The terms "comprise", "comprising", "include", "including", "contain", "containing", "have", "having", "carry", "carrying", "comprised of", "comprising of", "including of", "consist of", "consisting of", "consists of", "consisting of / for", "consists of / for" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover not exclusive inclusion. For example, a process, method, or system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally further comprises steps or units not listed, or optionally further comprises other steps or units inherent to the process, method, product or device. In addition, the terms "first", "second" and "third" and the like are used to distinguish different objects, rather than to describe a specific order.

[0065] As shown in Figures 1-4 The present embodiment provides a grating waveguide 100, comprising a waveguide substrate 10, and a coupling-in element 20, a first polarization reflection device 30, a coupling-out element 40 and a second polarization reflection device 50 arranged in the waveguide substrate 10 in sequence;

[0066] The first polarized light 101 from outside enters the waveguide substrate 10 through the coupling-in element 20, and is reflected to the coupling-out element 40 through the first polarization reflection device 30, and then diffracted by the coupling-out element 40 to form the first coupling-out light 102 and the first non-coupling-out light 103;

[0067] The first non-coupling-out light 103 propagates through the waveguide substrate 10 to the second polarization reflection device 50, and is reflected and the polarization direction is changed to form the second polarized light 104 by the second polarization reflection device 50;

[0068] The second polarized light 104 propagates through the waveguide substrate 10 to the coupling-out element 40, and is diffracted by the coupling-out element 40 to form the second coupling-out light 105 and the second non-coupling-out light 106;

[0069] The second non-coupling-out light 106 propagates through the waveguide substrate 10 to the first polarization reflection device 30, and is reflected to the coupling-out element 40 through the first polarization reflection device 30, and then diffracted by the coupling-out element 40 to form the third coupling-out light 107 and the third non-coupling-out light 108;

[0070] The third non-coupling-out light 108 propagates through the waveguide substrate 10 to the second polarization reflection device 50, and is reflected and the polarization direction is changed to form the third polarized light 109 by the second polarization reflection device 50;

[0071] The third polarized light ray 109 propagates through the waveguide substrate 10 to the out-coupling element 40, and is diffracted by the out-coupling element 40 to form a fourth out-coupled light ray 110 and a fourth non-coupled light ray 111.

[0072] The fourth non-coupled light ray 111 is reflected by the first polarized reflection device 30, and propagates through the waveguide substrate 10 to be emitted from a side of the waveguide substrate 10 away from the second polarized reflection device 50.

[0073] In applications, the waveguide substrate 10 can be a glass substrate layer, a plastic substrate layer, a crystal material substrate layer, or a composite material substrate layer made of a transparent material such as glass (e.g., quartz glass, BK7 glass, etc.), plastic (e.g., Polymeric Methyl Methacrylate (PMMA), Polycarbonate (PC), etc.), crystal material (e.g., sapphire (Al2O3), or composite material (e.g., doped or modified glass). The waveguide substrate 10 serves as a medium for the propagation of optical signals, supports total internal reflection of light rays within the waveguide substrate 10, and supports the coupling-in element 20, the first polarized reflection device 30, the coupling-out element 40, and the second polarized reflection device 50.

[0074] In applications, the coupling-in element 20 can be a lens-type coupling-in element, a prism-type coupling-in element, or a grating-type coupling-in element composed of a lens (e.g., a convex lens, a concave lens, or an aspheric lens, etc.), a prism, a grating (e.g., a surface relief grating or a volume holographic grating), etc., or the coupling-in element 20 is a fiber coupler or a microlens array. The coupling-in element 20 is used to efficiently couple the external first polarized light ray 101 into the interior of the waveguide substrate 10 by controlling the incident angle of the first polarized light ray 101 so that the first polarized light ray 101 satisfies the total internal reflection condition after entering the waveguide substrate 10.

[0075] In applications, the coupling-out element 40 can be a grating-type coupling-out element, a prism-type coupling-out element, or a mirror-type coupling-out element composed of a grating (e.g., a surface relief grating or a volume holographic grating), a prism, a mirror (e.g., a micro-mirror), etc., or the coupling-out element 40 is a fiber coupler or a microlens array. The coupling-out element 40 is used to efficiently couple out the optical signals propagating in the interior of the waveguide substrate 10 through total internal reflection and project them to a target area (e.g., a user's eye).

[0076] In the application, the polarization directions of the first polarized light 101 and the second polarized light 104 are perpendicular to each other, the polarization direction of the third polarized light 109 is the same as that of the first polarized light 101, for example, the first polarized light 101 is P (Parallel Polarization) light, and the second polarized light 104 is S (Perpendicular Polarization) light, and correspondingly, the first polarized light 101, the first out-coupled light 102, the first non-coupled light 103, the third polarized light 109 and the fourth non-coupled light 111 are all P light, and the second polarized light 104, the second out-coupled light 105, the second non-coupled light 106, the third out-coupled light 107 and the third non-coupled light 108 are all S light; the first polarized light 101 is S, and the second polarized light 104 is P light, and correspondingly, the first polarized light 101, the first out-coupled light 102, the first non-coupled light 103, the third polarized light 109 and the fourth non-coupled light 111 are all S light, and the second polarized light 104, the second out-coupled light 105, the second non-coupled light 106, the third out-coupled light 107 and the third non-coupled light 108 are all P light.

[0077] In the application, in the grating waveguide, the light enters the waveguide base through the coupling-in element and is totally internally reflected, and is reflected to the coupling-out element, and at the same time that the required order of diffraction light (defined as the out-coupled light in the embodiments of the present application) is obtained, other orders of diffraction light (defined as the non-coupled light in the embodiments of the present application) are also obtained due to the need for pupil expansion, and the diffraction efficiency of the non-coupled light needs to be very high to pass through the coupling-out element multiple times and be coupled out through the coupling-out element. Since the optical efficiency of the non-coupled light is much higher than that of the out-coupled light, the non-coupled light continues to propagate forward through the coupling-out element and is easily leaked out of the waveguide base, resulting in a large amount of light being wasted. The non-coupled light can be but is not limited to 0-order diffraction light, and can also be other orders of diffraction light, for example, ±1-order diffraction light, ±2-order diffraction light, ±3-order diffraction light, ±4-order diffraction light, ±5-order diffraction light, etc., and can also include multiple orders of diffraction light, for example, at least two orders of diffraction light among 0-order diffraction light, ±2-order diffraction light, ±3-order diffraction light, ±4-order diffraction light and ±5-order diffraction light.

[0078] The grating waveguide 100 provided in this embodiment allows the first polarized ray 101 to propagate through the coupling element 20 into the waveguide substrate 10. During this propagation, the ray passes through the coupling element 40 four times, forming four coupled-out rays (i.e., the first coupled-out ray 102, the second coupled-out ray 105, the third coupled-out ray 107, and the fourth coupled-out ray 110) and four uncoupled rays (i.e., the first uncoupled-out ray 103, the second uncoupled-out ray 106, the third uncoupled-out ray 108, and the fourth uncoupled-out ray 111). The four coupled-out rays... All outgoing rays exit the waveguide substrate 10 and are projected onto the user's eye, effectively improving the diffraction efficiency of the outgoing rays. Furthermore, the first three outgoing rays (i.e., the first outgoing ray 103, the second outgoing ray 106, and the third outgoing ray 108) continue to propagate within the waveguide substrate 10, while only the fourth outgoing ray (i.e., the fourth outgoing ray 111) leaks from one side of the waveguide substrate 10, thus improving the diffraction efficiency of the outgoing rays and reducing leakage, thereby improving the overall diffraction efficiency of the grating waveguide 100.

[0079] In application, the spacing between the coupling element 20, the first polarization reflector 30, the coupling element 40, and the second polarization reflector 50 on the waveguide substrate 10 can be set according to actual needs, as long as the transmission path of light in the grating waveguide 100 is satisfied.

[0080] like Figures 1-4 As shown, in one embodiment, the waveguide substrate 10 includes a first surface 11, a second surface 12, a third surface 13 and a fourth surface 14, the first surface 11 and the second surface 12 are disposed opposite to each other, and the third surface 13 and the fourth surface 14 are disposed opposite to each other and are respectively connected to the first surface 11 and the second surface 12.

[0081] The coupling element 20 is disposed on the first surface 11;

[0082] At least one of the first polarizing reflective device 30 and the coupling element 40 is disposed on the first surface 11 or the second surface 12;

[0083] The second polarization reflector 50 is disposed inside the waveguide substrate 10 and connected to the first surface 11 and the second surface 12, or the second polarization reflector 50 is disposed on the third surface 13;

[0084] The fourth non-coupled ray 111 is emitted from the fourth surface 14.

[0085] In applications, the coupling element 20, the first polarization reflector 30, the coupling element 40, and the second polarization reflector 50 are disposed on the waveguide substrate 10 in the following ways:

[0086] Method 1 (e.g.) Figure 1(As shown): The coupling element 20, the first polarization reflector 30 and the coupling element 40 are disposed on the first surface 11, and the second polarization reflector 50 is disposed inside the waveguide substrate 10;

[0087] Method 2 (e.g.) Figure 2 (As shown): The coupling element 20, the first polarization reflective device 30 and the coupling element 40 are disposed on the first surface 11, and the second polarization reflective device 50 is disposed on the third surface 13;

[0088] Method 3: The coupling element 20 is disposed on the first surface 11, the first polarization reflective device 30 and the coupling element 40 are disposed on the second surface 12, and the second polarization reflective device 50 is disposed inside the waveguide substrate 10;

[0089] Method 4: The coupling element 20 is disposed on the first surface 11, the first polarizing reflective device 30 and the coupling element 40 are disposed on the second surface 12, and the second polarizing reflective device 50 is disposed on the third surface 13;

[0090] Method 5: The coupling element 20 and the first polarization reflective device 30 are disposed on the first surface 11, the coupling element 40 is disposed on the second surface 12, and the second polarization reflective device 50 is disposed inside the waveguide substrate 10;

[0091] Method 6: The coupling element 20 and the first polarizing reflective device 30 are disposed on the first surface 11, the coupling element 40 is disposed on the second surface 12, and the second polarizing reflective device 50 is disposed on the third surface 13;

[0092] Method 7 (e.g.) Figure 3 (As shown): The coupling element 20 and the coupling element 40 are disposed on the first surface 11, the first polarization reflector 30 is disposed on the second surface 12, and the second polarization reflector 50 is disposed inside the waveguide substrate 10.

[0093] Method 8 (e.g.) Figure 4 As shown): the coupling element 20 and the coupling element 40 are disposed on the first surface 11, the first polarizing reflective device 30 is disposed on the second surface 12, and the second polarizing reflective device 50 is disposed on the third surface 13.

[0094] In applications, the coupling element 20, the first polarization reflector 30, the coupling element 40, and the second polarization reflector 50 can be directly attached to the surface of the waveguide substrate 10 or embedded in the surface of the waveguide substrate 10.

[0095] The embodiments of the present application provide various schemes of arranging the coupling-in element 20, the first polarization reflection device 30, the coupling-out element 40 and the second polarization reflection device 50 on the waveguide substrate 10, which improves the flexibility of the preparation process of the grating waveguide 100; by arranging the coupling-in element 20, the first polarization reflection device 30 and the coupling-out element 40 on the surface of the waveguide substrate 10, the coupling-in element 20, the first polarization reflection device 30 and the coupling-out element 40 can be prepared separately and then arranged on the waveguide substrate 10, which simplifies the preparation process of the grating waveguide 100.

[0096] As shown in FIG. 1, in one embodiment, the coupling-in element 20, the first polarization reflection device 30 and the coupling-out element 40 are arranged on the first surface 11 of the waveguide substrate 10. Figure 1 Figure 2 As shown in FIG. 1, in one embodiment, the coupling-in element 20, the first polarization reflection device 30 and the coupling-out element 40 are arranged on the first surface 11 of the waveguide substrate 10.

[0097] The embodiments of the present application arrange the coupling-in element 20, the first polarization reflection device 30 and the coupling-out element 40 on the same surface of the waveguide substrate 10, so that the coupling-in element 20, the first polarization reflection device 30 and the coupling-out element 40 can be attached to or embedded in the same surface of the waveguide substrate 10 in batches, which further simplifies the preparation process of the grating waveguide 100.

[0098] As shown in FIG. 1, in one embodiment, the coupling-in element 20, the first polarization reflection device 30 and the coupling-out element 40 are arranged on the first surface 11 of the waveguide substrate 10. Figure 2 Figure 4 As shown in FIG. 1, in one embodiment, the coupling-in element 20, the first polarization reflection device 30 and the coupling-out element 40 are arranged on the first surface 11 of the waveguide substrate 10.

[0099] The embodiments of the present application arrange the coupling-in element 20, the first polarization reflection device 30 and the coupling-out element 40 on the same surface of the waveguide substrate 10, so that the coupling-in element 20, the first polarization reflection device 30 and the coupling-out element 40 can be attached to or embedded in the same surface of the waveguide substrate 10 in batches, which further simplifies the preparation process of the grating waveguide 100.

[0100] As shown in FIG. 1, in one embodiment, the coupling-in element 20, the first polarization reflection device 30 and the coupling-out element 40 are arranged on the first surface 11 of the waveguide substrate 10. Figure 5 As shown in FIG. 1, in one embodiment, the first polarization reflection device 30 includes the first reflection element 31 and a plurality of first polarization reflection elements 32, the plurality of first polarization reflection elements 32 are spaced apart from each other and parallel, arranged between the first reflection element 31 and the waveguide substrate 10, and inclined at a specific angle relative to the first reflection element 31.

[0101] The first polarized light 101 is reflected by the first reflection element 31 and transmitted by the plurality of first polarization reflection elements 32 to the coupling-out element 40;

[0102] The second non-coupling-out light 106 is reflected by the plurality of first polarization reflection elements 32 to the coupling-out element 40 in the original path;

[0103] The fourth non-coupling-out light 111 is transmitted by the plurality of first polarization reflection elements 32 to the first reflection element 31 and reflected by the first reflection element 31 to the waveguide substrate 10. ​​

[0104] In application, the first reflective element 31 can be implemented based on a reflective mirror or a reflective film; when the first polarized ray 101 is P-ray, the first polarized reflective element 32 is implemented based on a P-ray transparent and S-ray reflective film; when the first polarized ray 101 is S-ray, the first polarized reflective element 32 is implemented based on an S-ray transparent and P-ray reflective film.

[0105] The embodiments of this application construct a first polarization reflection device 30 by using a first reflection element 31 and a plurality of first polarization reflection elements 32, and the first polarization reflection elements 32 are tilted relative to the first reflection element 31 at a specific angle, so that the incident light can return along the original path. The structure is simple and easy to implement.

[0106] like Figure 6 As shown, in one embodiment, the first polarization reflective device 30 further includes a plurality of first light-transmitting support elements 33 disposed between the first reflective element 31, a plurality of first polarization reflective elements 32 and the waveguide substrate 10.

[0107] In applications, the first light-transmitting support element 33 can be a glass substrate, plastic substrate, crystalline material substrate, or composite material substrate made of transparent materials such as glass (e.g., quartz glass, BK7 glass, etc.), plastic (e.g., polymethyl methacrylate, polycarbonate, etc.), crystalline material (e.g., sapphire), composite material (e.g., doped or modified glass), etc.

[0108] like Figure 7 As shown, in one embodiment, a method for fabricating a first polarizing reflective device 30 is provided, comprising the following steps:

[0109] By stacking multiple layers of the first light-transmitting support element substrate 34, a first preparatory body 301 is obtained;

[0110] A first polarizing reflective element 32 is inserted between every two adjacent first light-transmitting support element substrates 34 to obtain a second pre-body 302.

[0111] According to a specific angle (e.g., Figure 7 Cut the second preparatory body 302 along the dotted line direction in the diagram to obtain the third preparatory body 303;

[0112] The first reflective element 31 is attached to the surface of the third preparatory body 303 to obtain the first polarization reflective device 30.

[0113] The embodiments of this application construct a first polarization reflective device 30 by means of a first reflective element 31, a plurality of first polarization reflective elements 32 and a plurality of first light-transmitting support elements 33. The first polarization reflective device 30 can be made by stacking multiple layers of first light-transmitting support element substrates 34, inserting a layer of first polarization reflective element 32 between adjacent first light-transmitting support element substrates 34, and then cutting and attaching a layer of first reflective element 31 along a specific angle. The manufacturing process is simple and easy to implement.

[0114] In applications, the first polarization reflective device 30 can also be directly constructed by pasting together the first reflective element 31, a plurality of first polarization reflective elements 32 and a plurality of first light-transmitting support elements 33 that are individually cut at a specific angle.

[0115] like Figure 8 As shown, in one embodiment, the first polarization reflective device 30 includes a second polarization reflective element 35 and a plurality of second reflective elements 36. The second polarization reflective element 35 is disposed between the plurality of second reflective elements 36 and the waveguide substrate 10. The plurality of second reflective elements 36 are spaced apart from each other, parallel to each other, and tilted at a specific angle relative to the second polarization reflective element 35.

[0116] The first polarized ray 101 is reflected by the second polarization reflecting element 35 to the coupling element 40;

[0117] The second uncoupled light ray 106 is transmitted through the second polarization reflection element 35 to a plurality of second reflection elements 36, and is reflected by the plurality of second reflection elements 36 back to the second polarization reflection element 35, and then transmitted through the second polarization reflection element 35 to the coupling element 40;

[0118] The fourth uncoupled ray 111 is reflected by the second polarization reflecting element 35 to the waveguide substrate 10.

[0119] In application, when the first polarized ray 101 is P-ray, the second polarization reflective element 35 is based on a transmissive S-ray reflective P-ray film; when the first polarized ray 101 is S-ray, the second polarization reflective element 35 is based on a transmissive P-ray reflective S-ray film; the second reflective element 36 can be based on a reflective mirror or a reflective film.

[0120] In this embodiment, a first polarization reflective device 30 is constructed by a second polarization reflective element 35 and a plurality of second reflective elements 36, such that the second reflective elements 36 are tilted relative to the second polarization reflective element 35 at a specific angle, thereby enabling the incident light to return along its original path. The structure is simple and easy to implement.

[0121] like Figure 9 As shown, in one embodiment, the first polarization reflective device 30 further includes a second light-transmitting support element 37 disposed between the second polarization reflective element 35 and a plurality of second reflective elements 36.

[0122] In applications, the second light-transmitting support element 37 can be a glass substrate, plastic substrate, crystalline material substrate, or composite material substrate made of transparent materials such as glass (e.g., quartz glass, BK7 glass, etc.), plastic (e.g., polymethyl methacrylate, polycarbonate, etc.), crystalline material (e.g., sapphire), composite material (e.g., doped or modified glass), etc.

[0123] like Figure 10 As shown, in one embodiment, a method for fabricating a first polarizing reflective device 30 is provided, comprising the following steps:

[0124] According to a specific angle (e.g., Figure 10 Cut the second light-transmitting support element base 38 (in the direction of the dotted line) and form multiple serrated structures on one side of the second light-transmitting support element base 38 to obtain the second light-transmitting support element 37.

[0125] A second reflective element 36 is attached to each serrated surface of the second light-transmitting support element 37, and a second polarizing reflective element 35 is attached to the opposite side to obtain the first polarizing reflective device 30.

[0126] In this embodiment, a first polarization reflective device 30 is constructed by a second polarization reflective element 35, a plurality of second reflective elements 36, and a second light-transmitting support element 37. The first polarization reflective device 30 can be constructed by cutting one side of the substrate 38 of the second light-transmitting support element at a specific angle to form a plurality of serrated structures, attaching a layer of second reflective element 36 to the surface of each serrated structure, and then attaching a layer of second polarization reflective element 35 to the opposite side. The fabrication process is simple and easy to implement.

[0127] like Figure 11 As shown, in one embodiment, the second polarization reflective device 50 includes a quarter-wave plate 51 and a third reflective element 52, the third reflective element 52 being disposed on the side of the quarter-wave plate 51 away from the coupling element 40.

[0128] In applications, the third reflective element 52 can be implemented based on a reflective mirror or a reflective film.

[0129] In this embodiment, a second polarization reflector 50 is constructed using a quarter-wave plate 51 and a third reflective element 52, enabling the second polarization reflector 50 to reflect incident light and convert its polarization direction. The structure is simple and easy to implement.

[0130] like Figure 12 This application also provides a near-eye display system 1000, including an optomechanical system 200 and a grating waveguide 100 in any of the foregoing embodiments, wherein a first polarized light 101 is emitted by the optomechanical system 200 to the coupling element 20.

[0131] In applications, the light engine 200 can include, but is not limited to, an image generator (for example, a micro display implemented based on a Liquid Crystal on Silicon (LOCS), an Organic Electroluminescence Display (OLED), a Micro-LED, a Mini-LED, etc. display technology) for providing an image required light signal, a projection system (for example, a lens, a mirror, a prism, etc.) for processing (for example, collimating) and transmitting the light signal, a mechanical structure for supporting and fixing the optical elements, a driving device for controlling the movement of the optical elements, a control system for monitoring and adjusting the running state of the light engine, etc.

[0132] In applications, the near-eye display system 1000 can be applied to augmented reality devices, virtual reality devices and mixed reality devices, which can be set as any wearable device (for example, a smart helmet, a smart glasses) according to actual needs, and can also be other forms, for example, a Head Up Display (HUD).

[0133] The embodiment of the present application realizes the near-eye display system based on the grating waveguide with high diffraction efficiency, and improves the imaging quality of the near-eye display system.

[0134] The above-described embodiments are only used to illustrate the technical solutions of the present application, but not limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A grating waveguide, characterized by, The waveguide base body and the in-coupling element, the first polarization reflecting device, the out-coupling element and the second polarization reflecting device are sequentially and spaced apart from each other; The first polarized light from outside enters the waveguide base body through the in-coupling element, is reflected by the first polarization reflecting device to the out-coupling element, and is diffracted by the out-coupling element to form first out-coupled light and first non-coupled light; The first non-coupled light propagates through the waveguide base body to the second polarization reflecting device, is reflected by the second polarization reflecting device and changes the polarization direction to form second polarized light; The second polarized light propagates through the waveguide base body to the out-coupling element, and is diffracted by the out-coupling element to form second out-coupled light and second non-coupled light; The second non-coupled light propagates through the waveguide base body to the first polarization reflecting device, is reflected by the first polarization reflecting device to the out-coupling element, and is diffracted by the out-coupling element to form third out-coupled light and third non-coupled light; The third non-coupled light propagates through the waveguide base body to the second polarization reflecting device, is reflected by the second polarization reflecting device and changes the polarization direction to form third polarized light; The third polarized light propagates through the waveguide base body to the out-coupling element, and is diffracted by the out-coupling element to form fourth out-coupled light and fourth non-coupled light; The fourth non-coupled light is reflected by the first polarization reflecting device, propagates through the waveguide base body to the side of the waveguide base body away from the second polarization reflecting device, and exits from the fourth surface.

2. The grating waveguide of claim 1, wherein, The waveguide base body comprises a first surface, a second surface, a third surface and a fourth surface, the first surface and the second surface are oppositely arranged, and the third surface and the fourth surface are oppositely arranged and respectively connected to the first surface and the second surface; The in-coupling element is arranged on the first surface; At least one of the first polarization reflecting device and the out-coupling element is arranged on the first surface or the second surface; The second polarization reflecting device is arranged inside the waveguide base body and connected to the first surface and the second surface, or the second polarization reflecting device is arranged on the third surface; The fourth non-coupled light exits from the fourth surface.

3. The grating waveguide of claim 2, wherein, The in-coupling element, the first polarization reflecting device and the out-coupling element are arranged on the first surface.

4. The grating waveguide of claim 2 or 3, wherein, The second polarization reflecting device is arranged on the third surface.

5. The grating waveguide of claim 1, wherein, The first polarization reflecting device comprises a first reflecting element and a plurality of first polarization reflecting elements, the plurality of first polarization reflecting elements are spaced apart from each other and parallel, arranged between the first reflecting element and the waveguide base body, and inclined at a specific angle relative to the first reflecting element; The first polarized light is reflected by the first reflecting element and transmitted by the plurality of first polarization reflecting elements to the out-coupling element; The second non-coupled light is reflected by the plurality of first polarization reflecting elements to the out-coupling element; The fourth non-coupled light is transmitted by the plurality of first polarization reflecting elements to the first reflecting element, and is reflected by the first reflecting element to the waveguide base body.

6. The grating waveguide of claim 5, wherein, The first polarization reflection device further comprises a plurality of first light-transmitting support elements arranged between the first reflection element, the plurality of first polarization reflection elements and the waveguide substrate.

7. The grating waveguide of claim 1, wherein, The first polarization reflection device comprises a second polarization reflection element and a plurality of second reflection elements, the second polarization reflection element is arranged between the plurality of second reflection elements and the waveguide substrate, and the plurality of second reflection elements are spaced apart from each other, parallel and inclined at a specific angle relative to the second polarization reflection element. The first polarized light is reflected by the second polarization reflection element to the out-coupling element. The second non-coupled light is transmitted by the second polarization reflection element to the plurality of second reflection elements, and is reflected by the plurality of second reflection elements to the second polarization reflection element in the original path, and then is transmitted by the second polarization reflection element to the out-coupling element. The fourth non-coupled light is reflected by the second polarization reflection element to the waveguide substrate.

8. The grating waveguide of claim 7, wherein, The first polarization reflection device further comprises a second light-transmitting support element arranged between the second polarization reflection element and the plurality of second reflection elements.

9. The grating waveguide of claim 1, wherein, The second polarization reflection device comprises a 1 / 4 wave plate and a third reflection element, and the third reflection element is arranged on the side of the 1 / 4 wave plate away from the out-coupling element.

10. A near-eye display system, comprising: A light machine and a grating waveguide according to any one of claims 1-9 are comprised, and the first polarized light is emitted by the light machine to the in-coupling element.

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