An optical waveguide, an optical module and a display device

Abstract

This invention discloses an optical waveguide, an optical module, and a display device. The optical waveguide includes: at least two substrate layer structures; the at least two substrate layer structures are arranged side-by-side in a stacked manner, with a gap between adjacent layers; a plurality of microstructures are disposed on at least one of the substrate layer structures and located on at least one side of the substrate layer structure; an expansion film layer is located within the gap containing the microstructures and covers at least a portion of the surface of the microstructures; the expansion film layer reversibly absorbs liquid and expands. In this invention, by covering the surface of the microstructures with an expansion film layer, the expansion film layer supports the two adjacent layers when it absorbs liquid and expands, reducing or even preventing deformation of the two adjacent layers, thereby reducing the probability of the microstructures within the gap being squeezed and deformed, and avoiding damage to the microstructures.

Description

Technical Field

[0001] This invention relates to the field of display device technology, and in particular to an optical waveguide, an optical module, and a display device. Background Technology

[0002] In the fields of augmented reality (AR) and mixed reality (MR), compared with display solutions such as Bird Bath (BB, semi-reflective), insect eye (off-axis reflective), and freeform prism, the optical waveguide solution is thinner and lighter and has a larger eye box, thus having a broader application prospect.

[0003] Existing optical waveguide technology requires a protective layer structure 100 to prevent the microstructure 200 (surface relief grating, holographic grating, or metasurface) from direct contact with air. An air gap is required between the protective layer structure 100 and the substrate layer structure 300; otherwise, the microstructure 200 will be damaged. Figure 1 This is a schematic cross-sectional view of an existing optical waveguide under normal temperature and pressure conditions; under low temperature and low pressure environments, both the protective layer structure 100 and the substrate layer structure 300 are concave (e.g., Figure 2 As shown in the figure, this causes damage to the microstructure 200. Even if the external environment returns to normal temperature and pressure, the damaged microstructure 200 is difficult to recover, which will cause a decrease in the display effect of the optical waveguide.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an optical waveguide, an optical module and a display device in view of the above-mentioned defects of the prior art, so as to solve the technical problem that the concave protection layer structure and the substrate layer structure in the prior art cause damage to the microstructure.

[0006] The technical solution adopted by this invention to solve the technical problem is as follows:

[0007] An optical waveguide comprising:

[0008] At least two base layer structures; the at least two base layer structures are arranged side by side in an up-down stacked form, and there is a gap between two adjacent layer structures;

[0009] Multiple microstructures are disposed on at least one of the substrate layer structures and located on at least one side of the substrate layer structure;

[0010] An expansion membrane layer is located within the gap having the microstructure and covers at least a portion of the surface of the microstructure; the expansion membrane layer reversibly absorbs liquid and expands.

[0011] The optical waveguide is characterized in that, within the gap having a microstructure, the expansion film layer covers all or part of the surface of the microstructure with equal thickness, or covers the surface without a microstructure with equal thickness.

[0012] In the optical waveguide, within the gap having microstructures, the expansion film layer covers the surface of all microstructures, and the thickness of the expansion film layer gradually decreases from the middle to both sides.

[0013] The optical waveguide, wherein the expanded film layer comprises at least one of a polymer material, hydrogel, silicone, cobalt chloride, calcium chloride, ethanolamine, and cobalt complex-based superhygroscopic material.

[0014] The optical waveguide, wherein the expanded film layer can release water vapor and return to its original state when left to stand under sunlight and / or heating and / or drying.

[0015] The optical waveguide wherein the average thickness of the expanded film layer is 1 nm to 20 μm.

[0016] In the optical waveguide, at least one surface of the substrate structure and the microstructure is provided with a non-expansion film layer; when the surface of the microstructure is provided with a non-expansion film layer, the non-expansion film layer is located between the expansion film layer and the microstructure.

[0017] In the optical waveguide, of the at least two substrate structures, at least one substrate structure has a material and / or thickness that differs from the other substrate structures.

[0018] An optical module includes an optical waveguide as described in any of the above claims, and further includes a projection device arranged corresponding to the optical waveguide.

[0019] A display device comprising the optical module as described above.

[0020] Beneficial effects: In this invention, by covering the surface of the microstructure with an expansion film layer, the expansion film layer supports the two adjacent layers when it absorbs liquid and expands, reducing or even avoiding the deformation of the two adjacent layers, thereby reducing the probability of the microstructure being squeezed and deformed in the gap and avoiding damage to the microstructure. Attached Figure Description

[0021] Figure 1 This is a reference diagram showing the usage status of optical waveguides under normal temperature and pressure in existing technologies;

[0022] Figure 2 This is a reference diagram showing the usage status of optical waveguides under low temperature and low pressure in existing technologies;

[0023] Figure 3This is a reference diagram showing the usage state of the optical waveguide under normal temperature and pressure in this invention;

[0024] Figure 4 This is a reference diagram of the first usage state of the expansion membrane layer under low temperature and low pressure when it absorbs water and expands in this invention;

[0025] Figure 5 This is a reference diagram of the second usage state of the expansion membrane layer under low temperature and low pressure in this invention when it absorbs water and expands;

[0026] Figure 6 This is a schematic diagram of the optical waveguide structure when the expansion film layer covers the surface of the microstructure in the middle region within the gap with microstructures in this invention.

[0027] Figure 7 This is a schematic diagram of an optical waveguide structure in Embodiment 1 of the present invention, which is a combination of a base layer structure, a base layer structure, and a protective sheet structure.

[0028] Figure 8 This is a schematic diagram of an optical waveguide structure in Embodiment 1 of the present invention, which is a combination of a protective layer structure, a base layer structure, and a base layer structure.

[0029] Figure 9 This is a schematic diagram of an optical waveguide structure in Embodiment 2 of the present invention, which is a combination of a protective sheet structure, a substrate structure, and a protective sheet structure.

[0030] Figure 10 This is a schematic diagram of an optical waveguide structure in Embodiment 1 of the present invention, which is a substrate-substrate structure.

[0031] Figure 11 This is a schematic diagram of the straight groove envelope structure;

[0032] Figure 12 This is a schematic diagram of the helical tooth envelope structure;

[0033] Figure 13 This is a schematic diagram of the structure of the shimmering envelope;

[0034] Figure 14 This is a schematic diagram of the structure of the step envelope;

[0035] Figure 15 This is a schematic diagram of the structure of the curved envelope;

[0036] Figure 16 This is a schematic diagram of the structure of a holographic exposure grating;

[0037] Figure 17 This is a schematic diagram of the distribution of the non-expanding film layer in this invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0039] This invention provides an optical waveguide, such as Figure 3 As shown, the optical waveguide includes: the expanded film layer 1, at least two substrate structures 3, and a plurality of microstructures 4; wherein the substrate structure 3 is used to support the microstructures 4.

[0040] Specifically, when there are two base layer structures 3, and one of the base layer structures 3 supports the microstructure 4 while the other does not, the base layer structure that does not support the microstructure 4 can be referred to as the protective sheet structure 2. The two base layer structures 3 are arranged side-by-side in any combination (e.g., Figures 7-10 As shown), there is a gap 10 between any two adjacent layer structures. That is, regardless of whether there is one or more base layer structures 3 and protective sheet structures 2, the combination of base layer structures 3 and protective sheet structures 2 is not limited. For example, when there are multiple base layer structures 3 and protective sheet structures 2, they can be arranged alternately, or multiple base layer structures 3 can be arranged adjacently and the protective sheet structures 2 can be distributed around the periphery of multiple base layer structures 3, etc. It is only necessary to reserve a gap 10 between any two adjacent layer structures so that the microstructure 4 can be arranged in the gap on any side of the base layer structure 3.

[0041] The present invention does not limit the number of the base layer structure 3 and the protective sheet structure 2, so that the number of the base layer structure 3 and the protective sheet structure 2 can be adjusted according to actual needs, and the desired diffraction effect can be achieved through a multi-layer structure.

[0042] In one embodiment of the present invention, the at least two base layer structures 3 are made of the same material and have the same thickness.

[0043] In another embodiment of the present invention, at least one of the at least two base layer structures 3 has a material and / or thickness that is different from the material and / or thickness of the other base layer structures; that is, the material and / or thickness of the at least two base layer structures 3 of the present invention are not completely the same.

[0044] Embodiment 1 of the present invention

[0045] There are two base layer structures 3 and one protective sheet structure 2. Assuming the bottom layer is the human eye observation area, the arrangement of the base layer structure 3 and the protective sheet structure 2 can be: base layer structure 3 - base layer structure 3 - protective sheet structure 2 - human eye (e.g., ...). Figure 7 As shown, there are gaps 10 between two adjacent base layer structures 3 and between adjacent base layer structures 3 and protective sheet structures 2; alternatively, it can be: protective sheet structure 2 - base layer structure 3 - base layer structure 3 - human eye (e.g. Figure 8 As shown, there are gaps 10 between adjacent protective layer structures 2 and base layer structures 3, and between two adjacent base layer structures 3.

[0046] Embodiment 2 of the present invention

[0047] There is one base layer structure 3 and two protective sheet structures 2. The arrangement of the base layer structure 3 and the protective sheet structure 2 can be: protective sheet structure 2 - base layer structure 3 - protective sheet structure 2 (e.g., ...). Figure 9 As shown, there is a gap 10 between adjacent protective layer structures 2 and base layer structures 3.

[0048] Multiple microstructures 4 are disposed on the substrate structure 3 and located within the gap 10 on at least one side of the substrate structure 3; that is, when the substrate structure 3 has gaps 10 on both sides, the microstructures 4 can be disposed within the gaps 10 on both sides of the substrate structure 3, or the microstructures 4 can be disposed only within the gap 10 on either side of the substrate structure 3. The expansion film layer 1 is located within the gap 10 containing the microstructures 4 and covers at least a portion of the surface of the microstructures 4; the expansion film layer 1 can absorb liquid and expand, and recover upon heating.

[0049] Based on the characteristics of water vapor liquefaction during the low-temperature and low-pressure time interval 10, the expansion film layer 1 absorbs liquid and expands (e.g., under low-temperature and low-pressure conditions). Figure 4 and Figure 5 As shown), it supports the two adjacent layers, reduces or even avoids the deformation of the two adjacent layers, thereby reducing the probability of the microstructure 4 being squeezed and deformed within the gap 10, and avoiding damage to the microstructure 4.

[0050] In this invention, the expansion film layer 1 is reversibly liquid-absorbing and expanding. That is, in an environment opposite to the water vapor liquefaction environment, the expansion film layer 1 can release water vapor to restore the optical performance of the optical waveguide, thereby ensuring the diffraction characteristics of the microstructure 4. For example, under sunlight, heating, drying, or normal temperature and pressure conditions, the expansion film layer 1 can be left to stand and release water vapor to restore its original state.

[0051] It should be noted that the expansion film layer 1 is a transparent expansion film layer, so as to reduce or even avoid the adverse effects of the expansion film layer 1 on the light diffraction effect within the gap 10.

[0052] In this invention, by covering the surface of the microstructure 4 with the expansion film layer 1, the expansion film layer 1 supports the two adjacent layer structures when it absorbs liquid and expands, thereby reducing or even avoiding the deformation of the two adjacent layer structures, thus reducing the probability of the microstructure 4 being squeezed and deformed within the gap 10 and avoiding damage to the microstructure 4.

[0053] It should be noted that the microstructure 4 described in this invention can be disposed within the gap 10 on any side of the basal layer structure 3, so that the microstructure 4 can be located on the side of the basal layer structure 3 closer to the human eye or on the side of the basal layer structure 3 farther away from the human eye.

[0054] Specifically, based on the combination of base layer structure 3-base layer structure 3-protective sheet structure 2 in Embodiment 1 of the present invention, such as Figure 7 As shown, the microstructures 4 are arranged within both gaps 10, and the microstructures 4 within both gaps 10 are located on the side of the base layer structure 3 facing the protective sheet structure 2 (at this time, although the base layer structure 3 in the middle has gaps 10 on both sides, the microstructures 4 are only arranged on the side facing the protective sheet structure 2); when the human eye is located near the protective sheet structure 2, the microstructures 4 are located on the side of the base layer structure 3 closest to the human eye. It is worth noting that the two microstructures 4 within the two gaps 10 can be the same or different. The materials and / or thicknesses and / or shapes and / or sizes of the protective sheet structure 2 and the two base layer structures 3 can be the same or different. The thicknesses and / or shapes and / or sizes shown in the figure are only schematic, that is, the actual thicknesses and / or shapes and / or sizes can be the same or different.

[0055] Based on the combination of protective layer structure 2-base layer structure 3-base layer structure 3 in Embodiment 1 of this invention, such as Figure 8 As shown, the microstructure 4 is arranged in both gaps 10, and the microstructure 4 in both gaps 10 is located on the side of the base layer structure 3 facing the protective sheet structure 2 (at this time, although the base layer structure 3 in the middle has gaps 10 on both sides, the microstructure 4 is arranged only on the side facing the protective sheet structure 2); when the human eye is located near the outermost base layer structure 3, the microstructure 4 is located on the side of the base layer structure 3 away from the human eye.

[0056] It should be noted that, based on the base layer structure 3 in Embodiment 1 of the present invention, the base layer structure 3 may also have the following... Figure 10 Arrangement relationship; such as Figure 10As shown, the microstructure 4 is provided on both sides of the two base layer structures 3 facing each other.

[0057] Based on the combination of protective sheet structure 2-base layer structure 3-protective sheet structure 2 in Embodiment 2 of the present invention, such as Figure 9 As shown, the microstructure 4 is arranged in both gaps 10; when the human eye is located outside any of the protective sheet structures 2, the microstructure 4 is distributed on the side of the base layer structure 3 near the human eye and on the side away from the human eye.

[0058] The optical waveguide has an insertion region, an exit region, and / or a transition region. The insertion region converts a free-space beam (projected from the optical engine onto the waveguide) into a beam transmitted via total internal reflection within the substrate structure 3. The exit region performs the reverse process, partially converting the beam transmitted via total internal reflection into a free-space beam received by the human eye. In addition to the insertion and exit regions, one or more intermediate partitions, i.e., transition regions, may exist. It is understood that multiple microstructures 4 can be distributed within the insertion and / or exit and / or transition regions of the optical waveguide; that is, multiple microstructures 4 can be distributed within any one or more partitions of the optical waveguide. The expansion film layer 1 can cover any region of the microstructure 4.

[0059] One embodiment of the present invention, such as Figure 3 and Figure 7 As shown, a pad 5 is provided in each gap 10. The pad 5 is connected to the two adjacent layer structures to support the two adjacent layer structures, thereby ensuring that the gap 10 can be maintained between the two adjacent layer structures when the expansion film layer 1 is in an unexpanded or expanded state.

[0060] In one embodiment of this example, there is at least one pad 5 in each gap 10; it should be understood that the pads have an effect on the periphery of the waveguide, and there may be one or more of them. In the gap with the microstructure 4, the pads 5 are located on the periphery of the microstructure 4.

[0061] When water vapor liquefies at low temperature and low pressure, regardless of whether the base layer structure 3 or the protective sheet structure 2 undergoes inward concavity, the degree of deformation at different locations of the layer structure can be the same or different, generally with the greatest degree of concavity in the middle area. When the degree of deformation at different locations of the layer structure is the same, as in one embodiment of the present invention, within the gap 10 containing the microstructure 4, the expansion film layer 1 covers all surfaces of the microstructure 4 with equal thickness, or covers a portion of the surface of the microstructure 4 with equal thickness, or covers the surface without microstructure 4 with equal thickness.

[0062] When the deformation degree varies at different locations of the layered structure, if the same support strength is applied to the deformed layered structure, the protective effect of the expansion film layer 1 may be insufficient, resulting in some areas of the microstructure 4 still being damaged. Therefore, in one embodiment of the present invention, within the gap 10 containing the microstructure 4, the expansion film layer 1 covers a portion of the surface of the microstructure 4 with equal thickness (e.g., Figure 6 As shown, when the expansion film layer 1 expands, it supports the central region with the greatest concavity in the layer structure, making the distribution of the support strength of the expansion film layer 1 more consistent with the concavity deformation of the layer structure. This ultimately achieves the technical objective of preventing deformation of both the microstructure 4 and the layer structure under low temperature and low pressure conditions. In another embodiment of the invention, within the gap 10 containing the microstructure 4, the expansion film layer 1 covers all surfaces of the microstructure 4 with equal thickness, and the thickness of the expansion film layer 1 gradually decreases from the center to both sides. This ensures that when the expansion film layer 1 absorbs liquid and expands under low temperature and low pressure conditions, the central region of the expansion film layer 1 expands the most, while the two side regions expand relatively less. Therefore, the central region with the greatest concavity in the layer structure receives the greatest support strength, while the two side regions receive less support strength. The distribution of the support strength of the expansion film layer 1 more closely matches the concavity deformation of the layer structure, ultimately achieving the technical objective of preventing deformation of both the microstructure 4 and the layer structure under low temperature and low pressure conditions.

[0063] In one embodiment of the present invention, the expansion film layer 1 comprises at least one of polymeric materials, hydrogels, silica gels, cobalt chloride, calcium chloride, ethanolamine, and cobalt complex-based superhygroscopic materials; that is, the expansion film layer 1 can be made of any one or more of polymeric materials, hydrogels, silica gels, cobalt chloride, calcium chloride, ethanolamine, and cobalt complex-based superhygroscopic materials.

[0064] In one embodiment of the present invention, the microstructure 4 includes at least one of a surface relief grating, a holographic exposure grating, and a metasurface; that is, the microstructure 4 may include any one or more of a surface relief grating, a holographic exposure grating, and a metasurface. The surface relief grating may include a straight groove envelope (e.g., Figure 11 As shown), oblique tooth envelope (as shown) Figure 12 As shown), shimmering envelope (as shown) Figure 13 As shown), step envelope (as shown) Figure 14 (as shown) and curved bread (as shown) Figure 15 At least one envelope of (as shown); a holographic exposure grating (such as Figure 16 (As shown) can include a holographic grating envelope; the metasurface can include a straight groove envelope or a stepped envelope.

[0065] In one embodiment of the present invention, the average thickness of the expansion film layer 1 is 1 nm to 20 μm, which makes it more feasible to arrange the expansion film layer 1 on the microstructure 4, the expansion performance of the expansion film layer 1 is better, and it will not expand excessively while ensuring good support for the layer structure, thereby avoiding reverse deformation of the layer structure under the excessive support of the expansion film layer 1.

[0066] In one embodiment of the present invention, at least one surface of the substrate structure 3 and the microstructure 4 is provided with a non-expansion film layer 6 to enhance or alter the light transmission and / or light filtering properties and / or hardness of the substrate structure 3, and / or the diffraction properties of the microstructure 4. It should be noted that, as... Figure 17 As shown, when a non-expansion film layer 6 is disposed on the surface of the microstructure 4, the non-expansion film layer 6 is located between the expansion film layer 1 and the microstructure 4 to avoid adverse effects of the non-expansion film layer 6 on the deformation of the expansion film layer 1, ensuring that the expansion film layer 1 is located on the outermost side and can expand and recover normally. When the non-expansion film layer 6 is disposed on the surface of the base layer structure 3 having the microstructure 4, the non-expansion film layer 6 is located between the base layer structure 3 and the microstructure 4.

[0067] In one embodiment of this invention, the non-expanding film layer 6 includes at least one of a dielectric material and a metallic material; that is, the non-expanding film layer 6 may include any one or more of a dielectric material and a metallic material.

[0068] In one embodiment of the present invention, the substrate structure 3 includes at least one of glass, resin, plastic, and transparent ceramic; that is, the substrate structure 3 may include any one or more of glass, resin, plastic, and transparent ceramic.

[0069] In one embodiment of the present invention, the protective sheet structure 2 can be a flat plate structure or a curved surface structure; the base layer structure 3 can be a flat plate structure or a curved surface structure.

[0070] The present invention also provides an optical module, which includes an optical waveguide as described in any of the above claims, and further includes a projection device arranged corresponding to the optical waveguide. The projection device includes any one of a microLED (micro Light Emitting Diode Display) optical engine, an LCOS (Liquid Crystal On Silicon) optical engine, a DLP (Digital Light Processing) optical engine, and an LBS (Laser Beam Scanning) optical engine.

[0071] The present invention also provides a display device, which includes the optical module described above.

[0072] In summary, this invention provides an optical waveguide, an optical module, and a display device. The optical waveguide includes: at least two substrate layer structures; the at least two substrate layer structures are arranged side-by-side in a stacked configuration, with a gap between adjacent layers; a plurality of microstructures are disposed on at least one of the substrate layer structures and located on at least one side of the substrate layer structure; an expansion film layer is located within the gap containing the microstructures and covers at least a portion of the surface of the microstructures; the expansion film layer reversibly absorbs liquid and expands. In this invention, by covering the surface of the microstructures with an expansion film layer, the expansion film layer supports the two adjacent layers when it absorbs liquid and expands, reducing or even preventing deformation of the two adjacent layers, thereby reducing the probability of the microstructures within the gap being squeezed and deformed, and avoiding damage to the microstructures.

[0073] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An optical waveguide, characterized in that, It includes: At least two basal layer structures; The at least two base layer structures are arranged in an up-down stacked manner, and there is a gap between two adjacent base layer structures; Multiple microstructures are disposed on at least one of the substrate layer structures and located on at least one side of the substrate layer structure; An expansion membrane layer is located within the gap having the microstructure and covers at least a portion of the surface of the microstructure; the expansion membrane layer reversibly absorbs liquid and expands, such that when the expansion membrane layer absorbs liquid and expands, it supports two adjacent base layer structures.

2. The optical waveguide according to claim 1, characterized in that, Within a gap with microstructures, the expansion film layer covers all or part of the surface of the microstructures with equal thickness, or covers the surface without microstructures with equal thickness.

3. The optical waveguide according to claim 1, characterized in that, Within the gap with microstructures, the expansion film layer covers the surface of all microstructures, and the thickness of the expansion film layer gradually decreases from the middle to both sides.

4. The optical waveguide according to claim 1, characterized in that, The expanded membrane layer includes at least one of hydrogel, silicone, cobalt chloride, calcium chloride, ethanolamine, and cobalt complex-based superhygroscopic material.

5. The optical waveguide according to claim 1, characterized in that, The expanded membrane can release water vapor and return to its original state when left to stand under sunlight and / or heating and / or drying.

6. The optical waveguide according to claim 1, characterized in that, The average thickness of the expansion film layer is 1 nm to 20 μm.

7. The optical waveguide according to claim 1, characterized in that, In the substrate structure and the microstructure, at least one surface of the structure is provided with a non-expanding film layer; when the surface of the microstructure is provided with a non-expanding film layer, the non-expanding film layer is located between the expanding film layer and the microstructure.

8. The optical waveguide according to claim 1, characterized in that, Of the at least two base layer structures, at least one base layer structure has a different material and / or thickness than the other base layer structures.

9. An optical module, characterized in that, It includes an optical waveguide as described in any one of claims 1-8, and further includes a projection device arranged corresponding to the optical waveguide.

10. A display device, characterized in that, It includes the optical module as described in claim 9.

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