Optical waveguide structure and augmented reality display device

Abstract

The invention provides an optical waveguide structure. The optical waveguide structure comprises a first waveguide, a first coupling-in grating and a first coupling-out grating, the first waveguide has opposite first and second surfaces for receiving and guiding sub-image light having a first wavelength range to propagate along a first direction. The first coupling-in grating is arranged on the first surface and used for receiving the image light and coupling sub-image light with a first wavelength range into the first waveguide, and the grating direction of the first coupling-in grating has a first included angle relative to the first direction. The first coupling-out grating is used for receiving and coupling out the sub-image light which is emitted from the first waveguide and has the first wavelength range, and the grating direction of the first coupling-out grating has a second included angle relative to the first direction. Wherein the first included angle and the second included angle are not zero, and the grating direction of the first coupling-in grating is opposite to the grating direction of the first coupling-out grating. The invention further provides an augmented reality display device comprising the optical waveguide structure.

Description

Technical Field

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

[0002] With the development of science and technology, augmented reality (AR) technology is applied to various fields, such as games, education, medical care, retail, etc. AR display devices project the virtual image generated by calculation to the human eye through the display module and optical waveguide structure, and superimpose it with the real space to form a display effect that integrates virtual and real space. The common AR display devices on the market mainly use one-dimensional pupil expansion technology to expand the horizontal field of view, so that the user's eyes can see the displayed image when moving horizontally.

[0003] However, the above-mentioned one-dimensional pupil expansion technology is difficult to expand the field of view in the vertical direction. In addition, since the image light includes sub-image lights with different wavelength ranges when it is transmitted from the coupling-in grating to the coupling-out grating, the light with different wavelength ranges will gradually shift in different directions away from the central axis of the optical waveguide structure, resulting in an incomplete display image received by the human eye in the vertical direction. The display image seen by the user's eyes when moving in the vertical direction is incomplete, thereby reducing the field of view in the vertical direction, thereby affecting the display effect. Summary of the invention

[0004] The first aspect of the present application provides an optical waveguide structure, comprising:

[0005] A first waveguide having a first surface and a second surface opposite to each other, for receiving and guiding sub-image light having a first wavelength range to propagate along a first direction;

[0006] a first coupling grating, disposed on the first surface, for receiving image light and coupling the sub-image light having a first wavelength range into the first waveguide, wherein a grating direction of the first coupling grating has a first angle θ1 relative to the first direction; and

[0007] a first out-coupling grating, which is arranged on the first surface together with the first in-coupling grating and arranged along the first direction together with the first in-coupling grating, the first out-coupling grating being used to receive and out-couple the sub-image light having the first wavelength range emitted from the first waveguide, and the grating direction of the first out-coupling grating having a second angle θ2 relative to the first direction;

[0008] The first angle θ1 and the second angle θ2 are not zero, and the grating direction of the first coupling-in grating is opposite to the grating direction of the first coupling-out grating.

[0009] The optical waveguide structure provided by the embodiment of the present application is provided with a first coupling-in grating and a first coupling-out grating, wherein the grating direction of the first coupling-in grating is opposite to the grating direction of the first coupling-out grating, and a first angle between the grating direction of the first coupling-in grating and the first direction and a second angle between the grating direction of the first coupling-out grating and the first direction are not zero, so that the grating direction of the first coupling-in grating and the grating direction of the first coupling-out grating have an angle with respect to the first direction, which can reduce the angle of deviation of the sub-image light having a first wavelength range toward the central axis of the optical waveguide structure in the process of being transmitted from the first coupling-in grating to the first coupling-out grating, that is, The deviation angle of the sub-image light with the first wavelength range is reduced in the process of being transmitted from the first coupling-in grating to the first coupling-out grating, so that the field of view angle in the vertical direction perpendicular to the first direction can be increased without affecting the overall volume of the optical waveguide structure; when the optical waveguide structure is applied to an augmented reality display device, by increasing the field of view angle in the vertical direction perpendicular to the first direction, the user's eyes can receive the sub-image light with the first wavelength range in the vertical direction, so that the user's eyes can see the displayed image more completely when moving in the vertical direction, thereby enhancing the display effect without affecting the overall volume of the augmented reality display device.

[0010] In one embodiment, the first angle θ1 satisfies: -15°≤θ1<0°, 0°<θ1≤15°; the second angle θ2 satisfies: -180°<θ2≤-165°, 165°≤θ2<180°.

[0011] In one embodiment, the optical waveguide structure further comprises a second waveguide, a second incoupling grating and a second outcoupling grating;

[0012] The second waveguide has an opposite third surface and a fourth surface, the second waveguide is attached to one side of the first waveguide and covers the first coupling-in grating and the first coupling-out grating; the second waveguide is used to receive and guide the sub-image light having a second wavelength range to propagate along the first direction;

[0013] A second coupling grating is disposed on the third surface, and is used to receive and couple the sub-image light having a second wavelength range into the second waveguide, wherein the grating direction of the second coupling grating has a third angle θ3 relative to the first direction;

[0014] A second out-coupling grating and the second in-coupling grating are disposed on the third surface and are arranged along the first direction with the second in-coupling grating, the second out-coupling grating is used to receive and couple out the sub-image light having the second wavelength range emitted from the second waveguide, and the grating direction of the second out-coupling grating has a fourth angle θ4 with respect to the first direction;

[0015] The third angle θ3 and the fourth angle θ4 are not zero, and the grating direction of the second coupling-in grating is opposite to the grating direction of the second coupling-out grating.

[0016] The optical waveguide structure provided in the embodiment of the present application can make the grating direction of the second coupling grating and the grating direction of the second coupling grating have an angle with respect to the first direction by setting the second waveguide, the second coupling grating and the second coupling grating, so that the angle of deviation of the sub-image light with the second wavelength range toward the central axis of the optical waveguide structure in the process of transmitting from the second coupling grating to the second coupling grating can be reduced, that is, the deviation angle of the sub-image light with the same wavelength range or different wavelength ranges in the process of transmitting from the second coupling grating to the second coupling grating can be reduced, thereby increasing the field of view angle in the vertical direction perpendicular to the first direction without affecting the overall volume of the optical waveguide structure.

[0017] In one embodiment, the third angle θ3 satisfies: -15°≤θ3<0°, 0°<θ3≤15°; the fourth angle θ4 satisfies: -180°<θ4≤-165°, 165°≤θ4<180°.

[0018] In one embodiment, the refractive index of the second waveguide is in the range of 1.3-2.5.

[0019] In one embodiment, the length range of the grating period of the second coupling-in grating is 0.1 μm-10 μm; the length range of the grating period of the second coupling-out grating is 0.1 μm-10 μm.

[0020] In one embodiment, the second coupling-in grating is any one of an amplitude type grating and a phase type grating; the second coupling-out grating is any one of an amplitude type grating and a phase type grating.

[0021] In one embodiment, the optical waveguide structure further comprises a plurality of waveguides stacked on the first waveguide, a coupling-in grating and a coupling-out grating are arranged on a surface of each waveguide away from the first waveguide, and the coupling-in grating and the coupling-out grating are arranged along the first direction; different waveguides are used to receive and guide sub-image lights having the same wavelength range or different wavelength ranges to propagate along the first direction;

[0022] The grating direction of each of the coupling-in gratings has a non-zero angle relative to the first direction; the grating direction of each of the coupling-out gratings also has a non-zero angle relative to the first direction; the grating direction of each of the coupling-in gratings is opposite to the grating direction of each of the coupling-out gratings.

[0023] In one embodiment, the refractive index of the first waveguide is in the range of 1.3-2.5.

[0024] In one embodiment, the length range of the grating period of the first coupling-in grating is 0.1 μm-10 μm; the length range of the grating period of the first coupling-out grating is 0.1 μm-10 μm.

[0025] In one embodiment, the first coupling-in grating is any one of an amplitude type grating and a phase type grating; the first coupling-out grating is any one of an amplitude type grating and a phase type grating.

[0026] A second aspect of the present application provides an augmented reality display device, comprising:

[0027] A display module, the display module is used to emit image light; and

[0028] As in the optical waveguide structure described in any of the above embodiments, the optical waveguide structure is used to receive the image light.

[0029] In one embodiment, the image light includes a plurality of sub-image lights, and the wavelength ranges of the plurality of sub-image lights are different.

[0030] In the augmented reality display device provided by the embodiment of the present application, by setting the optical waveguide structure described in any of the above embodiments, the grating direction of the first coupling-in grating is opposite to the grating direction of the first coupling-out grating, and the first angle of the grating direction of the first coupling-in grating relative to the first direction and the second angle of the grating direction of the first coupling-out grating relative to the first direction are not zero, so that the grating direction of the first coupling-in grating and the grating direction of the first coupling-out grating have an angle relative to the first direction, which can reduce the sub-image light with a first wavelength range from the first coupling-in grating to the first coupling-out grating in the process of being transmitted to the optical waveguide structure The angle of the central axis deviation can be reduced, that is, the deviation angle of the sub-image light with the first wavelength range in the process of being transmitted from the first coupling-in grating to the first coupling-out grating can be reduced, so that the field of view angle in the vertical direction perpendicular to the first direction can be increased without affecting the overall volume of the optical waveguide structure. By increasing the field of view angle in the vertical direction perpendicular to the first direction, the user's eyes can receive the sub-image light with the first wavelength range in the vertical direction, so that the user's eyes can see the displayed image more completely when moving in the vertical direction, thereby not affecting the overall volume of the augmented reality display device and thus enhancing the display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 FIG. 1 is a schematic structural diagram of an optical waveguide structure according to an embodiment of the present application.

[0032] Figure 2 FIG. 1 is a schematic diagram of a light path of an optical waveguide structure according to an embodiment of the present application.

[0033] Figure 3 It is a schematic diagram of a first angle and a second angle according to an embodiment of the present application.

[0034] Figure 4 FIG. 1 is a schematic diagram of the angle space of the grating direction of the first coupling-in grating and the grating direction of the first coupling-out grating according to an embodiment of the present application.

[0035] Figure 5 Schematic diagram of a proportional optical waveguide structure of the present application.

[0036] Figure 6 This is a schematic diagram of the angle space of the grating direction of the coupling-in grating and the grating direction of the coupling-out grating in a proportional manner in the present application.

[0037] Figure 7 It is a schematic diagram of the third angle and the fourth angle of one embodiment of the present application.

[0038] Figure 8 FIG. 1 is a schematic structural diagram of an optical waveguide structure including a plurality of waveguides in an embodiment of the present application.

[0039] Fig. 9 FIG. 1 is a schematic diagram of a light path of an exposure system according to an embodiment of the present application.

[0040] Fig.10 FIG. 1 is a schematic diagram of an augmented reality display device according to an embodiment of the present application.

[0041] Description of main component symbols:

[0042] Optical waveguide structure 100

[0043] First Waveguide 1

[0044] First surface 11

[0045] Second surface 12

[0046] Waveguide 2

[0047] Incoupling grating 21

[0048] Outcoupling grating 23

[0049] First coupling grating 3

[0050] The first coupling grating 4

[0051] Second waveguide 5

[0052] The third surface 51

[0053] Fourth surface 52

[0054] Second coupling grating 6

[0055] The second outcoupling grating 7

[0056] Grating direction K1, K2, K3, K4, Kn1, Kn2

[0057] Exposure light path 700

[0058] Light source S1, S2

[0059] Grating negative 71

[0060] Base 73

[0061] Beam splitter 74

[0062] Augmented reality display device 900

[0063] Display module 91

[0064] Image light L0

[0065] Sub-image light L00

[0066] Sub-image light L1 having a first wavelength range

[0067] Sub-image light L2 having a second wavelength range

[0068] Collimation module 93

[0069] First direction X

[0070] The first angle θ1

[0071] The second angle θ2

[0072] The third angle θ3

[0073] The fourth angle θ4

[0074] Deviation angle θ

[0075] Vector angle θr

[0076] Human eye visible area E

[0077] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0078] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0079] It should be noted that when a component is referred to as being "fixed to" or "mounted on" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time. The term "and / or" used herein includes all and any combinations of one or more related listed items. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0080] In order to further explain the technical means and effects adopted by the present application to achieve the intended purpose, the present application is described in detail below in conjunction with the accompanying drawings and preferred implementation methods.

[0081] Please also read Figure 1 and Figure 2 The optical waveguide structure 100 of the embodiment of the present application comprises a first waveguide 1, a first coupling grating 3, a first coupling grating 4, a second waveguide 5, a second coupling grating 6 and a second coupling grating 7. The first coupling grating 3 and the first coupling grating 4 are arranged at intervals on a side surface of the first waveguide 1. The second waveguide 5 is attached to a side of the first coupling grating 3 and the first coupling grating 4 away from the first waveguide 1. The second coupling grating 6 and the second coupling grating 7 are arranged at intervals on a side surface of the second waveguide 5 away from the first waveguide 1.

[0082] The first waveguide 1 is generally in a plate-like structure and has a first surface 11 and a second surface 12 opposite to each other, and the first surface 11 and the second surface 12 have a generally rectangular outer contour. The first waveguide 1 extends along a first direction X, that is, the long side of the first surface 11 or the second surface 12 extends along the first direction X. The material of the first waveguide 1 is any one of transparent glass and plastic, such as any one of polyethylene terephthalate (PET), polycarbonate (PC) and polymethyl methacrylate (PMMA), which is not limited in the present application. The refractive index of the first waveguide 1 is in the range of 1.3-2.5, for example, the refractive index of the first waveguide 1 can be any value in the range of 1.3-1.5, 1.5-1.7, 1.7-1.9, 1.9-2.1, 2.1-2.3 and 2.3-2.5, which is not limited in the present application.

[0083] The first waveguide 1 is used to receive and guide a portion of the image light L0 incident from the first coupling grating 3 to propagate along the first direction X. Specifically, the first waveguide 1 is used to receive and guide the sub-image light L1 with a first wavelength range incident from the first coupling grating 3 to propagate along the first direction X. In this embodiment, the image light L0 includes a plurality of sub-image lights, each of which has a different wavelength range. Specifically, the image light L0 includes a sub-image light L1 and a sub-image light L2 with different wavelength ranges. For example, the sub-image light L1 with the first wavelength range may be red light, and the sub-image light L2 with the second wavelength range may be blue light. The first wavelength range may be 760nm-622nm, and the second wavelength range may be 450nm-435nm. In other embodiments, the image light L0 may also be monochromatic light, that is, the wavelength ranges of the sub-image light L1 and the sub-image light L2 are the same, which is not limited in this application. The first waveguide 1 is used to receive and guide the sub-image light L1 with a first wavelength range incident from the first coupling grating 3, and the second waveguide 5 is used to receive and guide the sub-image light L2 with a second wavelength range incident from the second coupling grating 6; in other embodiments, the image light L0 may also include a plurality of sub-image lights with different wavelength ranges, and the first waveguide 1 and the second waveguide 5 may be used to receive and guide the sub-image lights with one or several wavelength ranges incident from the first coupling grating 3 or the second coupling grating 6, which is not limited in the present application.

[0084] Please also read Figure 2 and Figure 3, the first coupling grating 3 is disposed on the first surface 11 of the first waveguide 1. Specifically, the first coupling grating 3 can be bonded to the first surface 11 of the first waveguide 1 by means of optical glue. The first coupling grating 3 is used to receive and couple the sub-image light L1 having a first wavelength range into the first waveguide 1. Specifically, when the image light L0 including different wavelength ranges is incident on the first coupling grating 3, since the wavelength range of the sub-image light L1 having the first wavelength range and the wavelength range of the sub-image light L2 having the second wavelength range are different, the sub-image light L1 having the first wavelength range is incident on the first coupling grating 3, the first coupling grating 3 receives and couples the sub-image light L1 having the first wavelength range into the first waveguide 1, and the sub-image light L2 having the second wavelength range passes through the first coupling grating 3 and is incident on the second coupling grating 6. In other embodiments, when the wavelength ranges of the sub-image light L1 and the sub-image light L2 are the same, part of the image light L0 (sub-image light L1) is incident on the first coupling-in grating 3, the first coupling-in grating 3 receives the sub-image light L1 and couples it into the first waveguide 1, and the sub-image light L1 is then coupled out to the human eye through the first coupling-out grating 4; part of the image light L0 (sub-image light L2) is incident on the second coupling-in grating 6 through the first coupling-in grating 3, the second coupling-in grating 6 receives the sub-image light L2 and couples it into the second waveguide 5, and the sub-image light L2 is then coupled out to the human eye through the second coupling-out grating 7; the diffraction efficiency of the first coupling-in grating 3 can be adjusted to adjust the intensity of light incident on the first waveguide 1 and the second waveguide 5, and the intensity of light emitted from the first coupling-out grating 4 and the second coupling-out grating 7 can be adjusted, thereby improving the uniformity of the intensity of light emitted from the optical waveguide structure 100.

[0085] Specifically, the first coupling grating 3 is a holographic diffraction grating, for example, the first coupling grating 3 is any one of an amplitude type grating and a phase type grating. The length range of the grating period of the first coupling grating 3 is 0.1 μm-10 μm. For example, the length of the grating period of the first coupling grating 3 can be any value in the range of 0.1 μm-1 μm, 1 μm-3 μm, 3 μm-5 μm, 5 μm-7 μm, 7 μm-8 μm and 8 μm-10 μm, and the present application does not limit it.

[0086] In this embodiment, the first coupling grating 3 is a grating having periodic light and dark stripes on the surface; in other embodiments, the first coupling grating 3 can also be other gratings with periodic structures, or the first coupling grating 3 is a grating with periodic changes in refractive index, which is not limited in this application. Specifically, the plurality of light and dark stripes of the first coupling grating 3 are approximately parallel, and the grating direction is perpendicular to the extension direction of the stripes, which also refers to the direction of the grating arrangement on the first coupling grating 3, and is also the periodic direction of the grating, that is, the grating extension order direction, that is, the vector direction of the grating projection on the first surface 11; the grating direction K1 of the first coupling grating 3 has a first angle θ1 relative to the first direction X. The first angle θ1 satisfies: -15°≤θ1<0°, 0°<θ1≤15°; for example, the first angle θ1 can be any value in the range of -15°≤θ1≤-10°, -10°≤θ1<0°, 0°<θ1≤10° and 10°≤θ1≤15°, and the present application does not impose any limitation thereto. By setting the first angle θ1 to satisfy the above range, while offsetting a portion of the sub-image light L1 having the first wavelength range at the exit position of the first outcoupling grating 4 relative to the central axis of the first waveguide 1, the sub-image light L1 having the first wavelength range will not be excessively offset, thereby generating an offset error.

[0087] The first coupling-in grating 3 and the first coupling-out grating 4 are arranged along the first direction X. The first coupling-out grating 4 is spaced apart from the first coupling-in grating 3 on the first surface 11. The first coupling-out grating 4 can be bonded to the first surface 11 of the first waveguide 1 by means of optical glue. The first coupling-out grating 4 is used to receive and couple out the sub-image light L1 having a first wavelength range emitted from the first waveguide 1. Specifically, the first coupling-out grating 4 is a holographic diffraction grating, for example, the first coupling-out grating 4 can be any one of an amplitude grating and a phase grating.

[0088] In the present embodiment, the first outcoupling grating 4 is a grating having periodic light and dark stripes on the surface; in other embodiments, the first outcoupling grating 4 may also be other gratings having periodic structures, or the first outcoupling grating 4 may be a grating having a periodic change in refractive index, which is not limited in the present application. The length of the grating period of the first outcoupling grating 4 is in the range of 0.1 μm-10 μm. For example, the length of the grating period of the first outcoupling grating 4 may be any value in the range of 0.1 μm-1 μm, 1 μm-3 μm, 3 μm-5 μm, 5 μm-7 μm, 7 μm-8 μm and 8 μm-10 μm, which is not limited in the present application.

[0089] The grating direction K2 of the first out-coupling grating 4 is parallel to the grating direction K1 of the first in-coupling grating 3, and the grating direction K1 of the first in-coupling grating 3 is opposite to the grating direction K2 of the first out-coupling grating 4. The grating direction K2 of the first out-coupling grating 4 has a second angle θ2 relative to the first direction X. The second angle θ2 satisfies: -180°<θ2≤-165°, 165°≤θ2<180°; for example, the second angle θ2 can be any value in the range of -180°<θ2≤-170°, -170°≤θ2≤-165°, 165°≤θ2≤170° and 170°≤θ2<180°, as long as the grating direction K2 of the first out-coupling grating 4 is parallel to the grating direction K1 of the first in-coupling grating 3, that is, the size of the first angle θ1 is equal to the size of the second angle θ2, and the present application does not impose any limitation. By setting the second angle θ2 to satisfy the above range, it is possible to offset a portion of the sub-image light L1 having the first wavelength range that is offset at the exit position of the first outcoupling grating 4 relative to the central axis of the first waveguide 1, while also preventing the sub-image light L1 having the first wavelength range from being excessively offset, thereby causing an offset error.

[0090] To ensure that the grating direction K2 of the first out-coupling grating 4 is parallel to the grating direction K1 of the first in-coupling grating 3, when the first angle θ1 is a negative angle, the second angle θ2 is a positive angle; in other embodiments, when the first angle θ1 is a positive angle, the second angle θ2 may also be a negative angle, which is not limited in the present application.

[0091] Specifically, the first angle θ1 and the second angle θ2 are both non-zero, that is, the grating direction K1 of the first coupling grating 3 relative to the first direction X and the grating direction K2 of the first coupling grating 4 relative to the first direction X both have an angle, see Figure 4 , Figure 4 : is a schematic diagram of the angle space of the grating direction K1 of the first coupling-in grating 3 and the grating direction K2 of the first coupling-out grating 4 in the embodiment of the present application, Figure 4 The schematic diagram shows the case when the first angle θ1 is 3° or the second angle θ2 is -177°. The grating direction K1 of the first coupling grating 3 is parallel to the grating direction K2 of the first coupling grating 4, that is, the magnitude of the first angle θ1 is equal to the magnitude of the second angle θ2, and the magnitude of the angle between the extension direction of the grating direction K1 of the first coupling grating 3 and the extension direction of the grating direction K2 of the first coupling grating 4 in the first direction X is defined as the vector angle θr.

[0092] Please also read Figure 5 and Figure 6In a pair of proportional optical waveguide structures, the first angle θ1 and the second angle θ2 are both zero, that is, the grating direction of the coupling-in grating is parallel to the first direction X and the grating direction of the coupling-out grating is parallel to the first direction X. When the light is transmitted from the coupling-in grating to the coupling-out grating, the light will gradually deviate in different directions away from the central axis of the optical waveguide structure, that is, the exit position of the light will have a deviation angle θ relative to the first direction X. Please refer to Figure 6 , Figure 6 Schematic diagram of the angle space of the grating direction of the coupling-in grating and the grating direction of the coupling-out grating in the comparative example. In the comparative example, since the first angle θ1 and the second angle θ2 are both zero, the vector angle θr of the angle between the extension direction of the grating direction of the coupling-in grating and the extension direction of the grating direction of the coupling-out grating and the first direction X is also 0. Due to the existence of the offset angle θ, the light emitted in the vertical direction perpendicular to the first direction X cannot be received in the visible area E of the human eye.

[0093] Please also refer to Figure 1 and Figure 2 In the optical waveguide structure 100 provided in the embodiment of the present application, a first angle θ1 of the grating direction K1 of the first coupling-in grating 3 relative to the first direction X and a second angle θ2 of the grating direction K2 of the first coupling-out grating 4 relative to the first direction X are set to be non-zero, that is, the angles between the extension direction of the grating direction of the first coupling-in grating 3 and the extension direction of the grating direction of the first coupling-out grating 4 and the first direction X are not zero, that is, the vector angle θr is also not zero. When the sub-image light L1 having the first wavelength range gradually deviates toward different directions away from the central axis of the optical waveguide structure 100, that is, the sub-image light L1 having the first wavelength range generates a deviation angle θ at the exit position of the first coupling-out grating 4 relative to the first direction X, due to the vector angle θr It exists, which can offset the influence of a portion of the sub-image light L1 with the first wavelength range having a deviation angle θ at the exit position of the first coupling grating 4 relative to the first direction X, that is, the actual deviation angle of the sub-image light L1 with the first wavelength range at the exit position of the first coupling grating 4 relative to the first direction X is θ-θr, wherein the size of θ-θr is smaller than the field of view angle received by the visible area E of the human eye in the vertical direction perpendicular to the first direction X, so that the sub-image light L1 with the first wavelength range emitted in the vertical direction perpendicular to the first direction X can be received in the visible area E of the human eye, thereby increasing the field of view angle in the vertical direction perpendicular to the first direction X without affecting the overall volume of the optical waveguide structure 100.

[0094] Please also read Figure 1 , Figure 2 and Figure 7The second waveguide 5 is roughly in a plate-like structure and has a third surface 51 and a fourth surface 52 opposite to each other. The third surface 51 and the fourth surface 52 have a roughly rectangular outer contour. The second waveguide 5 is attached to one side of the first waveguide 1 and covers the first coupling grating 3 and the first coupling grating 4; that is, the fourth surface 52 is attached to the side of the first coupling grating 3 and the first coupling grating 4 away from the first waveguide 1. The second waveguide 5 also extends along the first direction X, that is, the long side of the third surface 51 or the fourth surface 52 extends along the first direction X. The second waveguide 5 is used to receive and guide the sub-image light L2 with a second wavelength range incident from the second coupling grating 6. The material of the second waveguide 5 is any one of transparent glass and plastic, such as any one of PET, PC and PMMA, which is not limited in this application. The refractive index of the second waveguide 5 is in the range of 1.3-2.5. For example, the refractive index of the second waveguide 5 can be any value in the range of 1.3-1.5, 1.5-1.7, 1.7-1.9, 1.9-2.1, 2.1-2.3 and 2.3-2.5, which is not limited in the present application.

[0095] The second coupling grating 6 is disposed on the third surface 51. Specifically, the second coupling grating 6 can be bonded to the third surface 51 of the second waveguide 5 by optical glue. The second coupling grating 6 is used to receive and couple the sub-image light L2 having the second wavelength range into the second waveguide 5. Specifically, when the image light L0 including different wavelength ranges is incident on the second coupling grating 6, since the wavelength range of the sub-image light L1 having the first wavelength range is different from the wavelength range of the sub-image light L2 having the second wavelength range, the sub-image light L1 having the first wavelength range is incident on the first coupling grating 3, and the sub-image light L2 having the second wavelength range passes through the first coupling grating 3 and is incident on the second coupling grating 6. In other embodiments, when the wavelength ranges of the sub-image light L1 and the sub-image light L2 are the same, part of the image light L0 (sub-image light L1) is incident on the first coupling-in grating 3, the first coupling-in grating 3 receives the sub-image light L1 and couples it into the first waveguide 1, and the sub-image light L1 is then coupled out to the human eye through the first coupling-out grating 4; part of the image light L0 (sub-image light L2) is incident on the second coupling-in grating 6 through the first coupling-in grating 3, the second coupling-in grating 6 receives the sub-image light L2 and couples it into the second waveguide 5, and the sub-image light L2 is then coupled out to the human eye through the second coupling-out grating 7; the diffraction efficiency of the first coupling-in grating 3 can be adjusted to adjust the intensity of light incident on the first waveguide 1 and the second waveguide 5, and the intensity of light emitted from the first coupling-out grating 4 and the second coupling-out grating 7 can be adjusted, thereby improving the uniformity of the intensity of light emitted from the optical waveguide structure 100.

[0096] Specifically, the second coupling grating 6 is a holographic diffraction grating. For example, the second coupling grating 6 can be any one of an amplitude grating and a phase grating. In the present embodiment, the second coupling grating 6 is a grating having periodic light and dark stripes on the surface. In other embodiments, the second coupling grating 6 can also be other gratings with periodic structures, or the second coupling grating 6 is a grating with a periodic change in refractive index, which is not limited in the present application. The length of the grating period of the second coupling grating 6 is in the range of 0.1 μm-10 μm. For example, the length of the grating period of the second coupling grating 6 can be any value in the range of 0.1 μm-1 μm, 1 μm-3 μm, 3 μm-5 μm, 5 μm-7 μm, 7 μm-8 μm and 8 μm-10 μm, which is not limited in the present application.

[0097] The grating direction K3 of the second coupling-in grating 6 is opposite to the grating direction K4 of the second coupling-out grating 7. The grating direction K3 of the second coupling-in grating 6 has a third angle θ3 relative to the first direction X. The third angle θ3 satisfies: -15°≤θ3<0°, 0°<θ3≤15°; for example, the third angle θ3 can be any value in the range of -15°≤θ3≤-10°, -10°≤θ3<0°, 0°<θ3≤10° and 10°≤θ3≤15°, and the present application does not impose any limitation thereto.

[0098] The second coupling-in grating 6 and the second coupling-out grating 7 are arranged along the first direction X. The second coupling-out grating 7 is arranged on the third surface 51 at intervals from the second coupling-in grating 6. Specifically, the second coupling-out grating 7 can be bonded to the third surface 51 of the second waveguide 5 by optical glue. The second coupling-out grating 7 is used to receive and couple out the sub-image light L2 emitted from the second waveguide 5. Specifically, the second coupling-out grating 7 is a holographic diffraction grating, and the second coupling-out grating 7 is any one of an amplitude grating and a phase grating. For example, the second coupling-out grating 7 can be an amplitude grating. In the present embodiment, the second coupling-out grating 7 is a grating having periodic light and dark stripes on the surface; in other embodiments, the second coupling-out grating 7 can also be other gratings having a periodic structure, or the second coupling-out grating 7 is a grating having a periodic change in refractive index, which is not limited in the present application. The length range of the grating period of the second coupling-out grating 7 is 0.1 μm-10 μm. For example, the length of the grating period of the second outcoupling grating 7 can be any value in the range of 0.1 μm-1 μm, 1 μm-3 μm, 3 μm-5 μm, 5 μm-7 μm, 7 μm-8 μm and 8 μm-10 μm, which is not limited in the present application.

[0099] The grating direction K4 of the second out-coupling grating 7 has a fourth angle θ4 relative to the first direction X. The fourth angle θ4 satisfies: -180°<θ4≤-165°, 165°≤θ4<180°; for example, the fourth angle θ4 can be any value in the range of -180°<θ4≤-170°, -170°≤θ4≤-165°, 165°≤θ4≤170° and 170°≤θ4<180°, as long as the grating direction K4 of the second out-coupling grating 7 is opposite to the grating direction K3 of the second in-coupling grating 6, and the fourth angle θ4 and the second angle θ2 are opposite in positive and negative, that is, the grating direction K1 of the first in-coupling grating 3 is opposite to the grating direction K2 of the first out-coupling grating 4, and the present application does not impose any limitation. In order to prevent interference between the sub-image light L1 emitted from the first out-coupling grating 4 and the sub-image light L2 emitted from the second out-coupling grating 7, in this embodiment, the first angle θ1 is a negative angle, the second angle θ2 is a positive angle, the third angle θ3 is a positive angle, and the fourth angle θ4 is a negative angle. In other embodiments, the first angle θ1 is a positive angle, the second angle θ2 is a negative angle, the third angle θ3 is a negative angle, and the fourth angle θ4 is a positive angle, and this application does not limit this.

[0100] Please also read Figure 2 , Figure 4 and Figure 7, and similarly, the angle between the extension direction of the grating direction of the second coupling-in grating 6 and the extension direction of the grating direction of the second coupling-out grating 7 and the first direction X is defined as the vector angle θr. The optical waveguide structure 100 provided in the embodiment of the present application sets the third angle θ3 of the grating direction K3 of the second coupling-in grating 6 relative to the first direction X and the fourth angle θ4 of the grating direction K4 of the second coupling-out grating 7 relative to the first direction X to be non-zero, that is, the angle between the extension direction of the grating direction of the second coupling-in grating 6 and the extension direction of the grating direction of the second coupling-out grating 7 and the first direction X is not 0, that is, the vector angle θr is also not 0. When the sub-image light L2 with the second wavelength range gradually deviates toward different directions away from the central axis of the optical waveguide structure 100, that is, the sub-image light L2 with the second wavelength range will generate a deviation angle θ at the exit position of the second coupling-out grating 7 relative to the first direction X, due to the vector angle θr The existence of the structure can offset the effect of a deviation angle θ of a portion of the sub-image light L2 with the second wavelength range at the exit position of the second coupling grating 7 relative to the first direction X, that is, the actual deviation angle of the sub-image light L2 with the second wavelength range at the exit position of the second coupling grating 7 relative to the first direction X is θ-θr, wherein the size of θ-θr is smaller than the field angle of view received by the visible area E of the human eye in the vertical direction perpendicular to the first direction X, so that the sub-image light L2 with the second wavelength range emitted in the vertical direction perpendicular to the first direction X can be received in the visible area E of the human eye, thereby increasing the field angle of view in the vertical direction perpendicular to the first direction X without affecting the overall volume of the optical waveguide structure 100.

[0101] The optical waveguide structure 100 provided in the embodiment of the present application can make the grating direction K3 of the second coupling grating 6 and the grating direction K4 of the second coupling grating 7 have an angle with respect to the first direction X by setting the second waveguide 5, the second coupling grating 6 and the second coupling grating 7, so that the angle of deviation of the sub-image light L2 with the second wavelength range toward the central axis of the optical waveguide structure 100 in the process of being transmitted from the second coupling grating 6 to the second coupling grating 7 can be reduced, that is, the deviation angle θ of the sub-image light (the sub-image light L1 with the first wavelength range and the sub-image light L2 with the second wavelength range, the first wavelength range and the second wavelength range being the same or different) in the process of being transmitted from the second coupling grating 6 to the second coupling grating 7 can be reduced, thereby increasing the field of view in the vertical direction perpendicular to the first direction X without affecting the overall volume of the optical waveguide structure 100.

[0102] See also Figure 8In one embodiment, the optical waveguide structure 100 may further include a plurality of waveguides 2 stacked on the first waveguide 1, and a coupling-in grating 21 and a coupling-out grating 23 are disposed on a surface of each waveguide 2 away from the first waveguide 1, and the coupling-in grating 21 and the coupling-out grating 23 are arranged along the first direction X. Different waveguides 2 are used to receive and guide sub-image lights L00 having different wavelength ranges to propagate along the first direction X.

[0103] The grating direction Kn1 of each of the coupling-in gratings 21 has a non-zero angle with respect to the first direction X. The grating direction Kn2 of each of the coupling-out gratings 23 also has a non-zero angle with respect to the first direction X. The grating direction Kn1 of each of the coupling-in gratings 21 is opposite to the grating direction Kn2 of each of the coupling-out gratings 23. The optical waveguide structure 100 provided in the embodiment of the present application, through a plurality of waveguides 2 stacked on the first waveguide 1, can have a non-zero angle between the grating direction Kn1 of each of the coupling-in gratings 21 and the grating direction Kn2 of each of the coupling-out gratings 23 and the first direction X, thereby reducing the angle of deviation of the sub-image light L00 with different wavelength ranges toward the central axis of the optical waveguide structure 100 during the process of being transmitted from the coupling-in grating 21 to the coupling-out grating 23, that is, reducing the deviation angle θ of the sub-image light L00 with different wavelength ranges during the process of being transmitted from the coupling-in grating 21 to the coupling-out grating 23, thereby increasing the field of view in the vertical direction perpendicular to the first direction X without affecting the overall volume of the optical waveguide structure 100.

[0104] In other embodiments, if the image light L0 only includes sub-image light L0 having one wavelength range, the optical waveguide structure 100 may only include the first waveguide 1, the first coupling-in grating 3 and the first coupling-out grating 4, which is not limited in the present application.

[0105] Please also read Figure 1 and Fig. 9 , Fig. 9 An exposure optical path 700 is provided, and is used to manufacture any one of the first coupling-in grating 3 and the first coupling-out grating 4 or the second coupling-in grating 6 and the second coupling-out grating 7 in the embodiment of the present application. The exposure light source S1 or S2 is sequentially transformed into two sub-light beams with the same light intensity through the beam splitter 74. Each sub-light beam is reflected by a reflector and then incident on the grating film 71. The two sub-light beams interfere on the grating film 71 and form interference fringes on the grating film 71. Since the base 73 for fixing the grating film 71 is rotatable, the parallel angle of the interference fringes formed on the grating film 71 can be adjusted, that is, the grating direction of the formed holographic diffraction grating can be adjusted, so that the first coupling-in grating 3 and the first coupling-out grating 4 or the second coupling-in grating 6 and the second coupling-out grating 7 can be simultaneously exposed to obtain.

[0106] The optical waveguide structure 100 provided in the embodiment of the present application, by setting the first coupling-in grating 3 and the first coupling-out grating 4, the grating direction K1 of the first coupling-in grating 3 is parallel to the grating direction K2 of the first coupling-out grating 4, the grating direction K1 of the first coupling-in grating 3 and the grating direction K2 of the first coupling-out grating 4 are opposite, and the first angle θ1 of the grating direction K1 of the first coupling-in grating 3 relative to the first direction X and the second angle θ2 of the grating direction K2 of the first coupling-out grating 4 relative to the first direction X are not zero, the angle of the grating direction K2 of the first coupling-in grating 3 or the first coupling-out grating 4 relative to the first direction X can be increased, so that the sub-image light L1 with the first wavelength range can be reduced in the process of being transmitted from the first coupling-in grating 3 to the first coupling-out grating 4. The angle of the central axis offset of the waveguide structure 100 can reduce the offset angle of the sub-image light L1 with the first wavelength range in the process of being transmitted from the first coupling-in grating 3 to the first coupling-out grating 4, thereby increasing the field of view angle in the vertical direction perpendicular to the first direction X without affecting the overall volume of the optical waveguide structure 100; when the optical waveguide structure 100 is applied to the augmented reality display device 900, by increasing the field of view angle in the vertical direction perpendicular to the first direction X, the user's eyes can receive the sub-image light L1 with the first wavelength range in the vertical direction, so that the user's eyes can see the displayed image when moving in the vertical direction, which is beneficial to enhancing the display effect without affecting the overall volume of the augmented reality display device 900.

[0107] Please also read Figure 2 and Fig.10The augmented reality display device 900 of the embodiment of the present application includes a display module 91 and an optical waveguide structure 100 of any of the above embodiments. The display module 91 is used to emit image light L0. The image light L0 includes multiple sub-image lights, and each sub-image light has a different wavelength range. Specifically, the image light L0 includes a wavelength range of a sub-image light L1 with a first wavelength range and a sub-image light L2 with a second wavelength range. For example, the sub-image light L1 with the first wavelength range can be red light, and the sub-image light L2 with the second wavelength range can be blue light. In this embodiment, since the wavelength range of the sub-image light L1 with the first wavelength range is different from the wavelength range of the sub-image light L2 with the second wavelength range, the sub-image light L1 with the first wavelength range is incident on the first coupling grating 3, and the first coupling grating 3 receives and couples the sub-image light L1 with the first wavelength range into the first waveguide 1, and the sub-image light L2 with the second wavelength range passes through the first coupling grating 3 and is incident on the second coupling grating 6. In other embodiments, when the wavelength ranges of the sub-image light L1 and the sub-image light L2 are the same, part of the image light L0 (sub-image light L1) is incident on the first coupling-in grating 3, the first coupling-in grating 3 receives the sub-image light L1 and couples it into the first waveguide 1, and the sub-image light L1 is then coupled out to the human eye through the first coupling-out grating 4; part of the image light L0 (sub-image light L2) is incident on the second coupling-in grating 6 through the first coupling-in grating 3, the second coupling-in grating 6 receives the sub-image light L2 and couples it into the second waveguide 5, and the sub-image light L2 is then coupled out to the human eye through the second coupling-out grating 7.

[0108] Specifically, the display module 91 may be a display using a DLP (Digital Light Processor) display mode, or may be a light-emitting diode panel, such as a micro organic light-emitting diode panel or a micro light-emitting diode panel, which is not limited in this application. The augmented reality display device 900 further includes a collimator module 93, which is disposed on the light-emitting side of the display module 91, and is used to converge the image light L0 and transmit the image light L0 to the optical waveguide structure 100.

[0109] The augmented reality display device 900 provided in the embodiment of the present application is provided with the optical waveguide structure 100 in any of the above embodiments, and the first angle θ1 of the grating direction K1 of the first coupling grating 3 relative to the first direction X and the second angle θ2 of the grating direction K2 of the first coupling grating 4 relative to the first direction X in the optical waveguide structure 100 are not zero, and the grating direction K1 of the first coupling grating 3 and the grating direction K2 of the first coupling grating 4 are opposite, so that the grating direction K1 of the first coupling grating 3 and the grating direction K1 of the first coupling grating 4 have an angle relative to the first direction X, thereby reducing the sub-image light L1 having the first wavelength range from the first image L1 to the second image L1. The angle of deviation toward the central axis of the optical waveguide structure 100 during the process of transmitting the coupling-in grating 3 to the first coupling-out grating 4 can reduce the deviation angle of the sub-image light L1 with the first wavelength range during the process of transmitting from the first coupling-in grating 3 to the first coupling-out grating 4, thereby increasing the field of view angle in the vertical direction perpendicular to the first direction X. By increasing the field of view angle in the vertical direction perpendicular to the first direction X, the user's eyes can receive the sub-image light L1 with the first wavelength range in the vertical direction, so that the user's eyes can see the displayed image when moving in the vertical direction, which is beneficial to enhancing the display effect without affecting the overall volume.

[0110] The above implementation modes are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the above preferred implementation modes, a person skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. An optical waveguide structure, characterized in that: include: A first waveguide having a first surface and a second surface opposite to each other, for receiving and guiding sub-image light having a first wavelength range to propagate along a first direction; a first coupling grating, disposed on the first surface, for receiving and coupling the sub-image light having a first wavelength range into the first waveguide, wherein a grating direction of the first coupling grating has a first angle θ1 relative to the first direction; and a first out-coupling grating, which is arranged on the first surface together with the first in-coupling grating and arranged along the first direction together with the first in-coupling grating, the first out-coupling grating being used to receive and out-couple the sub-image light having the first wavelength range emitted from the first waveguide, and the grating direction of the first out-coupling grating having a second angle θ2 relative to the first direction; The first angle θ1 and the second angle θ2 are not zero, and the grating direction of the first coupling-in grating is opposite to the grating direction of the first coupling-out grating.

2. The optical waveguide structure according to claim 1, wherein: The first angle θ1 satisfies: -15°≤θ1<0°, 0°<θ1≤15°; The second angle θ2 satisfies: -180°<θ2≤-165°, 165°≤θ2<180°.

3. The optical waveguide structure according to claim 1, wherein: The optical waveguide structure further includes a second waveguide, a second incoupling grating and a second outcoupling grating; The second waveguide has an opposite third surface and a fourth surface, the second waveguide is attached to one side of the first waveguide and covers the first coupling-in grating and the first coupling-out grating; the second waveguide is used to receive and guide the sub-image light having a second wavelength range to propagate along the first direction; A second coupling grating is disposed on the third surface, and is used to receive and couple the sub-image light having a second wavelength range into the second waveguide, wherein the grating direction of the second coupling grating has a third angle θ3 relative to the first direction; A second out-coupling grating and the second in-coupling grating are disposed on the third surface and are arranged along the first direction with the second in-coupling grating, the second out-coupling grating is used to receive and couple out the sub-image light having the second wavelength range emitted from the second waveguide, and the grating direction of the second out-coupling grating has a fourth angle θ4 with respect to the first direction; The third angle θ3 and the fourth angle θ4 are not zero, and the grating direction of the second coupling-in grating is opposite to the grating direction of the second coupling-out grating.

4. The optical waveguide structure according to claim 3, characterized in that The third angle θ3 satisfies: -15°≤θ3<0°, 0°<θ3≤15°; the fourth angle θ4 satisfies: -180°<θ4≤-165°, 165°≤θ4<180°.

5. The optical waveguide structure according to claim 3, wherein: The refractive index of the second waveguide is in the range of 1.3-2.

5.

6. The optical waveguide structure according to claim 3, characterized in that: The length range of the grating period of the second coupling-in grating is 0.1 μm-10 μm; the length range of the grating period of the second coupling-out grating is 0.1 μm-10 μm.

7. The optical waveguide structure according to claim 3, characterized in that: The second coupling-in grating is any one of an amplitude type grating and a phase type grating; the second coupling-out grating is any one of an amplitude type grating and a phase type grating.

8. The optical waveguide structure according to claim 1, wherein: The optical waveguide structure further comprises a plurality of waveguides stacked on the first waveguide, wherein a coupling-in grating and a coupling-out grating are arranged on a surface of each waveguide away from the first waveguide, and the coupling-in grating and the coupling-out grating are arranged along the first direction; different waveguides are used to receive and guide sub-image lights having the same wavelength range or different wavelength ranges to propagate along the first direction; The grating direction of each of the coupling-in gratings has a non-zero angle relative to the first direction; the grating direction of each of the coupling-out gratings also has a non-zero angle relative to the first direction; the grating direction of each of the coupling-in gratings is opposite to the grating direction of each of the coupling-out gratings.

9. The optical waveguide structure according to claim 1, wherein: The refractive index of the first waveguide is in the range of 1.3-2.

5.

10. The optical waveguide structure according to claim 1, wherein: The length range of the grating period of the first coupling-in grating is 0.1 μm-10 μm; the length range of the grating period of the first coupling-out grating is 0.1 μm-10 μm.

11. The optical waveguide structure according to claim 1, wherein: The first coupling-in grating is any one of an amplitude type grating and a phase type grating; the first coupling-out grating is any one of an amplitude type grating and a phase type grating.

12. An augmented reality display device, characterized in that: include: A display module, the display module is used to emit image light; as well as The optical waveguide structure according to any one of claims 1 to 11, wherein the optical waveguide structure is used to receive the image light.

13. The augmented reality display device according to claim 12, wherein: The image light includes a plurality of sub-image lights, and the wavelength ranges of the plurality of sub-image lights are different.

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