Optical waveguide structure, display assembly and augmented reality display equipment

Abstract

The invention discloses an optical waveguide structure, a display assembly and an augmented reality display device, and relates to the technical field of optical waveguide structures.The optical waveguide structure comprises a substrate, a coupling-in grating and a coupling-out grating, the coupling-in grating and the coupling-out grating are arranged on the substrate, the coupling-in grating is used for coupling light into the substrate so that the light can be transmitted in the substrate through total reflection, and the coupling-out grating is used for coupling the light into the substrate; the coupling-out grating is used for receiving and coupling out light transmitted in the substrate; wherein the coupling-in grating comprises a grating structure and a transition structure, and the grating structure is arranged on one side of the substrate and used for coupling light into the substrate; the transition structure is stacked on the incident surface of the grating structure, a medium exists on the peripheral side of the coupled-in grating, the refractive index of the transition structure is smaller than the refractive index of the grating structure and larger than the refractive index of the medium, and the transition structure is used for enabling light to be incident to the grating structure and restraining the light incident to the surface of the grating structure from being emitted to the outside of the coupled-in grating. According to the technical scheme, the reflectivity of the coupled grating to light can be reduced, and the imaging effect of the display assembly is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of optical waveguide structures, and in particular to an optical waveguide structure, a display component and an augmented reality display device. Background Art

[0002] In the related art, the display components of augmented reality products usually include a light-emitting structure and an optical waveguide structure. The light emitted by the light-emitting structure can be coupled into the optical waveguide structure through the coupling grating of the optical waveguide structure, so as to be transmitted to the human eye through the optical waveguide structure. In the process of light coupling into the optical waveguide structure, due to the optical characteristics of the optical waveguide structure, part of the light incident on the coupling grating will be reflected back to the light-emitting structure, and then reflected back to the optical waveguide structure through the light-emitting structure, which will cause the formation of ghost images and affect the imaging effect of the display component. Summary of the invention

[0003] The main purpose of the present invention is to provide an optical waveguide structure, a display component and an augmented reality display device, aiming to reduce the reflectivity of the coupled grating to the light and ensure the imaging effect of the display component.

[0004] To achieve the above-mentioned object, the optical waveguide structure proposed in the present invention comprises a substrate and an in-coupling grating and an out-coupling grating arranged on the substrate, wherein the in-coupling grating is used to couple light into the substrate so that the light propagates in the substrate through total reflection, and the out-coupling grating is used to receive the light propagating in the substrate and couple the light out of the substrate through diffraction;

[0005] Wherein, there is a medium on the peripheral side of the coupling-in grating, and the coupling-in grating comprises:

[0006] A grating structure is disposed on the substrate, wherein at least one surface of the grating structure exposed outside the substrate is a light incident surface; and

[0007] A transition structure, the transition structure is stacked on the light incident surface of the grating structure, and is used to allow light to be incident on the grating structure and to suppress the light incident on the surface of the grating structure from being emitted to the outside of the coupling grating;

[0008] The refractive index of the transition structure is n c , the refractive index of the medium is n a , the refractive index of the grating structure is n g , then: 1 / 3(n g +n a )≤n c ≤2 / 3(n g +n a ).

[0009] In one embodiment, the peripheral side of the coupling-in grating includes the upper side of the coupling-in grating and the side of the coupling-in grating. When the medium above the coupling-in grating is different from the medium on the side of the coupling-in grating, the refractive index n of the medium is a is the refractive index of the medium above the coupling-in grating.

[0010] In one embodiment, the refractive index n of the medium is a Satisfy: 1<n a ≤1.5.

[0011] In one embodiment, the refractive index of the transition structure is n c Satisfies: 1.4≤n c ≤2.1.

[0012] In one embodiment, an end surface of the grating structure facing away from the substrate is the light incident surface, and the transition structure is stacked on an end of the grating structure facing away from the substrate and completely covers the end surface of the grating structure facing away from the substrate.

[0013] In one embodiment, the transition structure has an extended thickness in a direction away from the substrate, and the extended thickness ranges from greater than or equal to 10 nm to less than or equal to 150 nm.

[0014] In one embodiment, an end surface of the transition structure facing away from the grating structure is arranged in parallel with the light incident surface, so that the transition structure is arranged with equal thickness in a direction facing away from the substrate.

[0015] In one implementation, the grating height of the grating structure is H, which satisfies: 30nm≤H≤300nm.

[0016] The present invention also proposes a display component, comprising a light emitting structure and an optical waveguide structure as described in any one of the above, wherein the light emitting structure is used to emit light within a preset field of view angle range, and the optical waveguide structure is arranged on the light emitting side of the light emitting structure to receive and transmit the light emitted by the light emitting structure.

[0017] In one embodiment, the optical axis direction of the light source is arranged parallel to the normal direction of the substrate surface.

[0018] In one embodiment, the diameter of the region where the coupling grating of the optical waveguide structure is located is d, the field angle of the light output structure is θ, and the distance from the light output structure to the coupling grating is X, then: d / 2tan(θ / 2)≤X≤d / tan(θ / 2).

[0019] The present invention also provides an augmented reality display device, comprising any one of the display components described above.

[0020] The optical waveguide structure of the technical solution of the present invention comprises a substrate and an in-coupling grating and an out-coupling grating arranged on the substrate, wherein the in-coupling grating comprises a grating structure and a transition structure for coupling light into the substrate. The transition structure is stacked on the light incident surface of the grating structure, and the refractive index of the transition structure is less than the refractive index of the grating structure, and greater than the medium existing on the periphery of the in-coupling grating. In this arrangement, when light is transmitted into the transition structure through the medium and incident on the surface of the grating structure, part of the light reflected from the surface of the grating structure to the outside of the in-coupling grating can produce an interference effect under the modulation of the transition structure, so that the light reflected by the grating structure is coherently destructed, thereby effectively inhibiting the light incident on the surface of the grating structure from being emitted to the outside of the in-coupling grating, thereby reducing the reflectivity of the in-coupling grating to the light, and further reducing the risk of light forming ghost images entering the optical waveguide structure, which is beneficial to improving the imaging effect of the display component. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0022] Figure 1 A schematic structural diagram of an embodiment of an optical waveguide structure provided by the present invention;

[0023] Figure 2 for Figure 1 The red light diffraction efficiency diagram of the medium light waveguide structure;

[0024] Figure 3 for Figure 1 Green light diffraction efficiency diagram of the medium-light waveguide structure;

[0025] Figure 4 for Figure 1 Blue light diffraction efficiency diagram of the mid-light waveguide structure.

[0026] Figure 5 A schematic structural diagram of an embodiment of a display assembly provided by the present invention;

[0027] Figure 6 This is a schematic structural diagram of another embodiment of the display assembly provided by the present invention.

[0028] Description of Figure Numbers:

[0029] 1000, display component; 100, optical waveguide structure; 10, substrate; 20, coupling-in grating; 21, grating structure; 22, transition structure; 30, coupling-out grating; 200, light output structure.

[0030] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0033] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0034] In the related art, the display components of augmented reality products usually include a light-emitting structure and an optical waveguide structure. The light emitted by the light-emitting structure can be coupled into the optical waveguide structure through the coupling grating of the optical waveguide structure, so as to be transmitted to the human eye through the optical waveguide structure. In the process of light coupling into the optical waveguide structure, due to the optical characteristics of the optical waveguide structure, part of the light incident on the coupling grating will be reflected back to the light-emitting structure, and then reflected back to the optical waveguide structure through the light-emitting structure, which will cause the formation of ghost images and affect the imaging effect of the display component.

[0035] To this end, the present invention proposes an optical waveguide structure, wherein the coupling-in grating includes a grating structure for coupling-in light and a transition structure stacked on the light incident surface of the grating structure, and the refractive index of the transition structure is smaller than the refractive index of the grating structure and larger than the refractive index of the medium around the coupling-in grating, so that the reflectivity of the coupling-in grating to 0R-order light can be reduced by the transition structure, and the light incident on the surface of the grating structure is suppressed from being emitted to the outside of the coupling-in grating, so as to avoid the light being emitted to the outside of the coupling-in grating and then being reflected back to the optical waveguide structure to form a ghost image.

[0036] The optical waveguide structure 100 of the present application is described below with reference to a specific embodiment.

[0037] See also Figure 1 In one embodiment of the present invention, the optical waveguide structure 100 includes a substrate 10 and an in-coupling grating 20 and an out-coupling grating 30 disposed on the substrate 10. The in-coupling grating 30 is used to couple light into the substrate 10 so that the light propagates in the substrate 10 through total reflection. The out-coupling grating 30 is used to receive the light propagating in the substrate 10 and couple the light out of the substrate 10 through diffraction.

[0038] There is a medium on the peripheral side of the coupling-in grating 20, and the coupling-in grating 20 includes:

[0039] A grating structure 21 is disposed on the substrate 10, wherein at least one surface of the grating structure 21 exposed outside the substrate 10 is a light incident surface; and

[0040] The transition structure 22 is stacked on the light incident surface of the grating structure 21 , and is used to allow the light to be incident on the grating structure 21 , and to suppress the light incident on the surface of the grating structure 21 from being emitted to the outside of the coupled-in grating 20 .

[0041] Specifically in this embodiment, the optical waveguide structure 100 is used to receive the light emitted by the light-emitting structure 200 in the display component 1000, and is used to transmit the light to the human eye. Specifically, the light emitted by the light-emitting structure 200 can be incident on the coupling-in grating 20 through the medium on the peripheral side of the coupling-in grating 20, and then transmitted to the grating structure 22 through the transition structure 22, and coupled into the substrate 10 by the grating structure 21, so that the light coupled into the substrate 10 is totally reflected in the substrate 10 at a certain total reflection angle and propagates to the coupling-out grating 30, and the coupling-out grating 30 couples the light outward, so that the light can be transmitted to the human eye.

[0042] The substrate 10 is also called a dielectric optical waveguide, which is usually made of a material with the same refractive index, and the specific material can be, but is not limited to, silicon dioxide, resin, etc. The substrate 10 can be planar, and in other embodiments, the substrate 10 can also be cylindrical, or other shapes, which can be specifically designed according to the product to which it is applied.

[0043] The coupling-in grating 20 is arranged on a surface of the substrate 10, and specifically includes a grating structure 21 and a transition structure 22 covering the outer surface of the grating structure 21. The grating structure 21 can be attached to the substrate 10 as a separate optical element, or the grating structure 21 can be processed and formed on the substrate 10. The transition structure 22 can be stacked on the light incident surface of the grating structure 21 by, but not limited to, spin coating, inkjet printing, deposition and other processes. Optionally, the material of the grating structure 21 can be the same as the material of the substrate 10, or it can be set to a high refractive index material such as a dielectric material; the material of the transition structure 22 can be a resin, an inorganic material, etc. There is a medium on the surrounding side of the coupling-in grating 20, and the medium can be set to an air medium, or it can be set to a low refractive index material covering the surrounding side of the coupling-in grating 20.

[0044] The outcoupling grating 30 is disposed on a surface of the substrate 10, and can be disposed on the same side of the substrate 10 as the incoupling grating 20, or can be disposed on opposite sides of the substrate 10. The outcoupling grating 30 can be attached to the substrate 10 as a separate optical element, or a grating structure 21 can be formed on the substrate 10. When the light coupled into the substrate 10 by the incoupling grating 20 propagates in the substrate 10 through total reflection and is emitted to the outcoupling grating 30, the incident angle of the light can be deflected again, so that at least part of the light propagating to the outcoupling grating 30 can be coupled out of the substrate 10 by diffraction, and then emitted from the optical waveguide structure 100 to the human eye to form a display image and be captured by the human eye.

[0045] It can be understood that in the technical solution of the present invention, there is a medium around the coupling grating 20, and the refractive index of the transition structure 22 is less than the refractive index of the grating structure 21, and greater than the refractive index of the medium. By limiting the refractive index of the transition structure 22 so that its refractive index is between the external medium of the coupling grating 20 and the grating structure 21, when the light is transmitted into the transition structure 22 through the medium and incident on the surface of the grating structure 21, part of the light reflected from the surface of the grating structure 21 to the outside of the coupling grating 20 can produce an interference effect under the modulation of the transition structure 22, so that the light reflected by the grating structure 21 is coherently destructed, thereby effectively inhibiting the light incident on the surface of the grating structure 21 from emitting to the outside of the coupling grating 20, thereby reducing the reflectivity of the coupling grating 20 to the light, and further reducing the risk of light forming ghost images entering the optical waveguide structure 100, which is beneficial to improving the imaging effect of the display component 1000.

[0046] In the embodiment of the present invention, the refractive index of the transition structure 22 is n c , the refractive index of the medium is n a , the refractive index of the grating structure 21 is n g , then: 1 / 3(n g +n a )≤n c≤2 / 3(n g +n a ). Such a configuration can ensure the effect of suppressing the light reflectivity of the transition structure 22.

[0047] Preferably, the refractive index n of the transition structure 22 is c It can also be further restricted to satisfy the condition: 2 / 5(n g +n a )≤n c ≤3 / 5(n g +n a ) so that the coupled-in grating 20 has extremely low reflection efficiency for 0R order light.

[0048] In the embodiment of the present invention, the refractive index of the transition structure 22 may be in the range of 1.4 to 2.1, for example, it may be 1.4, 1.6, 1.8, 2.0, 2.1 and any value between 1.4 and 2.1, and the specific value may be determined according to the refractive index of the grating structure 21 and the medium. With such a configuration, the transition structure 22 may be used to reduce the reflectivity of the 0R-order light of the conventional binary grating. Of course, the specific value of the refractive index of the transition structure 22 may also be determined as other values ​​according to the refractive index of the grating structure 21 and the medium around the coupling grating 20 in the optical waveguide structure 100, which is not limited here.

[0049] In some embodiments, the material of the transition structure 22 can be specifically set to one of resin, titanium oxide, aluminum oxide, and silicon oxide. When the material of the transition structure 22 is resin, the transition structure 22 can be stacked on the light incident surface of the grating structure 21 through a spin coating or inkjet printing process. When the transition structure 22 is an inorganic material such as titanium oxide, aluminum oxide, silicon oxide, etc., the transition structure 22 can be stacked on the light incident surface of the grating structure 21 through a physical vapor deposition, chemical vapor deposition or atomic layer deposition process. Of course, the transition structure 22 can also be set to other inorganic materials that meet the refractive index requirements, and the specific implementation method can be set according to actual needs and is not limited here.

[0050] In one embodiment of the present invention, the medium above the coupling grating 20 and the medium on the side of the coupling grating 20 may also be set to be the same medium. That is, the refractive index of the medium around the coupling grating 20 is n a .

[0051] The bottom end of the coupling grating 20 is connected to the substrate 10, and the top end is extended in a direction away from the substrate 10. The medium above the coupling grating 20 is the medium located at the end face of the coupling grating 20 away from the substrate 10. The medium on the side of the coupling grating 20 is the medium located at the opposite sides of the coupling grating 20.

[0052] In another embodiment of the present invention, the medium above the coupling-in grating 20 is different from the medium on the side of the coupling-in grating 20. The refractive index of the medium above the coupling-in grating 20 is n a .

[0053] In this embodiment, the light of the light-emitting structure 200 is mainly transmitted to the coupling-in grating 20 through the medium located above the coupling-in grating 20. The medium above the coupling-in grating 20 is set to n a , which can meet the setting requirements of the transition structure 22. Among them, the refractive index of the medium above the coupling grating 20 is lower than that of the transition structure 22, and can be set as an air medium or a low-refractive-index material whose refractive index is lower than that of the transition structure 22. By making the medium above the coupling grating 20 different from the medium on the side of the coupling grating 20, the setting flexibility of the optical waveguide structure 100 can be achieved to adapt to different usage scenarios.

[0054] In addition, the refractive index of the medium on the side of the coupling-in grating 20 may be greater than or equal to the refractive index of the medium above the coupling-in grating 20. a The refractive index of the medium coupled into the grating 20 side can be greater than or equal to the medium of the grating structure 21, or can be less than the medium of the grating structure 21, which is not limited here.

[0055] In an embodiment of the present invention, the refractive index n of the medium a Satisfy: 1<n a ≤1.5.

[0056] In this embodiment, the medium is set to be a material other than air, specifically, it can be set to a material such as resin, silicon oxide, etc. Among them, the refractive index n a Greater than the refractive index of air, its refractive index n a The value range may be 1 to 1.5, for example, may be 1.1, 1.2, 1.3, 1.4, 1.5 and any value between 1.0 and 1.5.

[0057] It should be noted that, in order to ensure the protection performance of the optical waveguide structure 100 , a waveguide cover is usually stacked on the optical waveguide structure 100 , and the medium coupled into the peripheral side of the grating 20 is filled between the waveguide cover and the substrate 10 .

[0058] Compared with the technical solution of setting the medium around the coupling grating to air, by setting the medium around the coupling grating 20 to have a refractive index of 1<n a ≤1.5, you can use the refractive index of 1<n a The material with a g / cm3 of ≤1.5 fills the gap between the substrate 10 of the optical waveguide structure 100 and the waveguide cover plate, thereby further ensuring the protection performance of the optical waveguide structure 100 in a high temperature and high humidity environment and improving the pass rate of the optical waveguide structure 100 in a drop test.

[0059] See also Figure 1 In an embodiment of the present invention, an end surface of the grating structure 21 away from the substrate 10 is a light incident surface, and the transition structure 22 is stacked on an end of the grating structure 21 away from the substrate 10 and completely covers the end surface of the grating structure 21 away from the substrate 10.

[0060] In this embodiment, the light emitted from the light emitting structure 200 toward the optical waveguide structure 100 may be incident on the coupling grating 20 along a normal direction parallel to the surface of the substrate 10, and the light incident surface is located at the end of the grating structure 21 away from the substrate 10. At this time, by arranging the transition structure 20 at the end of the grating structure 21 away from the substrate 10, the transition structure 22 can modulate the light received and reflected by the grating structure 21 to reduce the reflectivity of the 0R-order light.

[0061] Of course, the technical solution of the present invention is not limited thereto. In other embodiments, the light emitted from the light emitting structure 200 toward the optical waveguide structure 100 may also be arranged to be inclined with respect to the normal direction of the surface of the substrate 10. The transition structure 22 may simultaneously cover the end of the grating structure 21 away from the substrate 10 and one of the side portions of the grating structure 21, so that the light transmitted to the grating structure 21 can all be emitted to the outside of the coupled-in grating 20 through the transition structure 22 after being reflected by the grating structure 21. Alternatively, the transition structure 22 may also simultaneously cover the end of the grating structure 21 away from the substrate 10 and the opposite sides of the grating structure 21, so as to achieve full coverage of the grating structure 21, so as to further ensure the inhibitory effect of the transition structure 22 on the reflected light of the grating structure 21.

[0062] In the embodiment of the present invention, the transition structure 22 has an extended thickness in a direction away from the substrate 10 , and the extended thickness ranges from greater than or equal to 10 nm to less than or equal to 150 nm.

[0063] In one embodiment, the transition structure 22 is arranged with equal thickness in a direction away from the substrate 10. Assuming the thickness of the transition structure 22 is D, the following is satisfied: 10 nm ≤ D ≤ 150 nm.

[0064] In this embodiment, the thickness of the transition structure 22 may be in the range of 10 nm, 30 nm, 50 nm, 70 nm, 90 nm, 110 nm, 130 nm, 150 nm, and any value between 10 nm and 150 nm. In this way, by limiting the thickness of the transition structure 22, it is possible to avoid the transition structure 22 being too thin to affect the effect of suppressing the light reflectivity, and to avoid the transition structure 22 being too thick to cause the coupled grating 20 to oscillate.

[0065] Preferably, the thickness of the transition structure 22 can be further limited to satisfy the condition: 30nm≤D≤150nm. Such a setting is conducive to further ensuring the inhibitory effect of the transition structure 22 on the reflectivity of the 0R-order light.

[0066] In other embodiments, the transition structure 22 is arranged with non-uniform thickness in the direction away from the substrate 10, that is, the side of the transition structure 22 away from the grating structure 21 may also be in other shapes such as an inclined surface and an arc surface. It is only necessary that the thickness range of the transition structure 22 at any position in the normal direction of the surface of the substrate 10 satisfies the preset thickness range of 10nm to 150nm. The present application does not limit the outer contour of the transition structure 22.

[0067] In the present embodiment, the thickness range of the transition structure 22 at any position in the normal direction of the surface of the substrate 10 can be further limited to satisfy a preset thickness range of 30 nm to 150 nm, so as to avoid the transition structure 22 being too thin and affecting the effect of suppressing the light reflectivity, and to avoid the transition structure 22 being too thick and causing oscillation of the coupled grating 20.

[0068] See also Figure 1 In an embodiment of the present invention, an end surface of the transition structure 22 facing away from the grating structure 21 is arranged parallel to the light incident surface, so that the transition structure 22 is arranged with equal thickness in a direction away from the substrate 10 .

[0069] In this embodiment, the transition structure 22 may be, but is not limited to, a rectangular structure, and the side thereof facing away from the grating structure 21 is a plane. In this way, the transition structure 22 covering the end of the grating structure 21 facing away from the substrate 10 can be arranged with equal thickness in the normal direction of the surface of the substrate 10, and each part of the transition structure 22 can meet the minimum thickness requirement, thereby facilitating the reduction of the volume occupied by the transition structure 22. In addition, by making the side of the transition structure 22 facing away from the grating structure 21 a plane, the processing and forming of the transition structure 22 can also be facilitated.

[0070] In other embodiments, the side of the transition structure 22 away from the grating structure 21 may also be in other shapes such as an inclined surface or an arc surface. It is only necessary that the thickness of the transition structure 22 in the normal direction of the surface of the substrate 10 meets a preset thickness range. The present application does not limit the outer contour of the transition structure 22.

[0071] In the embodiment of the present invention, the grating height of the grating structure 21 is H, which satisfies: 30nm≤H≤300nm.

[0072] Specifically, the grating height of the grating structure 21 can be in the range of 30nm, 60nm, 90nm, 120nm, 150nm, 180nm, 210nm, 240nm, 270nm, 300nm and any value between 30nm and 300nm. In this way, by limiting the height of the grating structure 21, it is possible to avoid the grating structure 21 being too small to affect the coupling effect of the grating structure 21 on light, and at the same time, it is possible to avoid the grating structure 21 being too large to increase the process difficulty and production cost of the grating structure 21.

[0073] The optical performance of the optical waveguide structure 100 proposed by the present invention will be described in a specific embodiment below:

[0074] See also Figures 2 to 4 , Figure 2 FIG. 1 is a diagram showing the red light diffraction efficiency of an embodiment of the optical waveguide structure 100 provided by the present invention. Figure 3 is a green light diffraction efficiency diagram of the optical waveguide structure 100, Figure 4 : is a blue light diffraction efficiency diagram of the optical waveguide structure 100. As shown in the figure, the horizontal axis is the grating height of the grating structure 21, and the vertical axis is the reflection efficiency of the 0R order light at different grating heights.

[0075] In this embodiment, the refractive index n of the substrate 10 is s is 2.0, and the refractive index n of the grating structure 21 is g is 2.4, and the refractive index n of the transition structure 22 is c is 1.7, the refractive index of the medium n a is 1.0, the incident light of the optical waveguide structure 100 is a normal incident light, that is, the light is incident on the coupling grating 20 along the normal direction parallel to the surface of the substrate 10. Figures 2 to 4 As shown, when the grating height is about 200nm, the reflection efficiency of red light, green light and blue light in the light of the ordinate OR order is about 2%, 1% and 0.4%. It can be seen that the coupling grating 20 of the optical waveguide structure 100 can have a good suppression effect on the reflected light of the OR order.

[0076] See also Figures 5 and 6 The present invention also proposes a display component 1000, which includes a light-emitting structure 200 and an optical waveguide structure 100. The specific structure of the optical waveguide structure 100 refers to the above embodiment. Since the display component 1000 adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here. Among them, the light-emitting structure 200 is used to emit light within a preset field of view angle range, and the optical waveguide structure 100 is arranged on the light-emitting side of the light-emitting structure 200, and is used to receive and transmit the light emitted by the light-emitting structure 200.

[0077] The light output structure 200 can provide incident light for the optical waveguide structure 100, and can make the incident light emit to the optical waveguide structure 100 within a predetermined field angle range. The light output structure 200 can be specifically set as a DLP optical engine, an LCOS optical engine, etc., which is not limited here.

[0078] Specifically in the present embodiment, the light emitted by the light emitting structure 200 includes RGB three-color light, that is, the light emitted by the light emitting structure 200 includes a red light beam R, a blue light beam B, and a green light beam G. The RGB three-color light can be incident on the coupling region of the optical waveguide structure 100 at the same incident angle, so as to be coupled into the substrate 10 through the coupling grating 20.

[0079] Of course, if Figure 6 As shown, in another embodiment, the optical axis direction of the light emitting structure 200 can also be tilted relative to the normal direction of the surface of the substrate 10. In this way, the light reflected by the optical waveguide structure 100 can be deflected out of the range where the light emitting structure 200 is located, so as to reduce the risk of the light being reflected back to the optical waveguide structure 100 by the light emitting structure 200, thereby helping to ensure the image display effect of the display component 1000.

[0080] Among them, the value range of the field of view angle θ of the light output structure 200 can be less than or equal to 40°. Such a setting can avoid the field of view angle of the light output structure 200 being too large, which will cause the deflection angle required by the display component 1000 to be too large, causing difficulties in implementing the solution.

[0081] like Figure 5 As shown, in one embodiment, the optical axis direction of the light-emitting structure 200 can be arranged parallel to the normal direction of the surface of the substrate 10. In this way, the light emitted by the light-emitting structure 200 can be incident on the coupling-in grating 20 at a vertical angle, which is suitable for an optical solution with a larger field of view FOV of the light-emitting structure 200.

[0082] Among them, the field of view angle θ of the light emitting structure 200 can range from 40° to 50°. With such a setting, the field of view angle of the light emitting structure 200 can be set to a larger value to avoid the field of view angle of the light emitting structure 200 being too small, resulting in the light projected by the display component 1000 to the human eye being unable to cover the visible field of view of the human eye, thereby affecting the display effect of the display component 1000.

[0083] Of course, the field of view angle θ of the light output structure 200 can also be set to be greater than 50° or less than 40°, and the light output structure 200 can also provide incident light for the optical waveguide structure 100. The specific implementation method can be set according to actual needs and is not limited here.

[0084] Further, in the embodiment of the present invention, the diameter of the region where the coupling grating 20 of the optical waveguide structure 100 is located is d, the field angle of the light-emitting structure 200 is θ, and the distance from the light-emitting structure 200 to the optical waveguide structure 100 is X, then the following is satisfied: d / 2tan(θ / 2)≤X≤d / tan(θ / 2). In this way, the risk of light being reflected back to the light-emitting structure 200 by the coupling grating 20 can be reduced by appropriately increasing the distance between the light-emitting structure 200 and the coupling grating 20 of the optical waveguide structure 100, while ensuring that the light emitted from the light-emitting structure 200 is normally coupled into the optical waveguide structure 100, thereby facilitating the intensity of the ghost image.

[0085] The present invention further proposes an augmented reality display device, which includes a display component 1000. The specific structure of the display component 1000 refers to the above embodiment. Since the augmented reality display device adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0086] The specific device type of the augmented reality display device is not limited in this embodiment. For example, the augmented reality display device can be a head-mounted display device such as AR glasses and AR helmets. The specific implementation method can be set according to actual needs.

[0087] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An optical waveguide structure, characterized in that: The optical waveguide structure comprises a substrate and an in-coupling grating and an out-coupling grating arranged on the substrate, wherein the in-coupling grating is used to couple light into the substrate so that the light propagates in the substrate through total reflection, and the out-coupling grating is used to receive the light propagating in the substrate and couple the light out of the substrate through diffraction; Wherein, there is a medium on the peripheral side of the coupling-in grating, and the coupling-in grating comprises: A grating structure is disposed on the substrate, wherein at least one surface of the grating structure exposed outside the substrate is a light incident surface; and A transition structure, the transition structure is stacked on the light incident surface of the grating structure, and is used to allow light to be incident on the grating structure and to suppress the light incident on the surface of the grating structure from being emitted to the outside of the coupling grating; The refractive index of the transition structure is n c , the refractive index of the medium is n a , the refractive index of the grating structure is n g , then: 1 / 3(n g +n a )≤n c ≤2 / 3(n g +n a ).

2. The optical waveguide structure according to claim 1, wherein: The peripheral side of the coupling-in grating includes the top of the coupling-in grating and the side of the coupling-in grating. When the medium above the coupling-in grating is different from the medium on the side of the coupling-in grating, the refractive index n of the medium is a is the refractive index of the medium above the coupling-in grating.

3. The optical waveguide structure according to any one of claims 1 to 2, characterized in that: The refractive index n of the medium a Satisfy: 1<n a ≤1.

5.

4. The optical waveguide structure according to any one of claims 1 to 2, characterized in that: The refractive index n of the transition structure c Satisfies: 1.4≤n c ≤2.

1.

5. The optical waveguide structure according to any one of claims 1 to 2, characterized in that: An end surface of the grating structure away from the substrate is the light incident surface, and the transition structure is stacked on an end of the grating structure away from the substrate and completely covers the end surface of the grating structure away from the substrate.

6. The optical waveguide structure according to claim 5, characterized in that The transition structure has an extension thickness in a direction away from the substrate, and the extension thickness ranges from greater than or equal to 10 nm to less than or equal to 150 nm.

7. The optical waveguide structure according to claim 5, characterized in that: An end surface of the transition structure away from the grating structure is arranged parallel to the light incident surface, so that the transition structure is arranged with equal thickness in a direction away from the substrate.

8. The optical waveguide structure according to any one of claims 1 to 2, characterized in that: The grating height of the grating structure is H, which satisfies: 30nm≤H≤300nm.

9. A display component, characterized in that: It comprises a light emitting structure and an optical waveguide structure as described in any one of claims 1 to 8, wherein the light emitting structure is used to emit light within a preset field of view angle range, and the optical waveguide structure is arranged on the light emitting side of the light emitting structure to receive and transmit the light emitted by the light emitting structure.

10. The display assembly according to claim 9, characterized in that The optical axis direction of the light source is arranged parallel to the normal direction of the substrate surface.

11. The display assembly according to claim 10, characterized in that The diameter of the region where the coupling grating of the optical waveguide structure is located is d, the field angle of the light output structure is θ, and the distance from the light output structure to the coupling grating is X, then: d / 2tan(θ / 2)≤X≤d / tan(θ / 2).

12. An augmented reality display device, characterized in that: Comprising the display assembly as claimed in any one of claims 9 to 11.

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