Diffraction optical waveguide

Abstract

According to the diffraction optical waveguide provided by the invention, the first magnetic coating and the second magnetic coating which are different in magnetism are arranged on the opposite surfaces between the waveguide sheet and the cover plate of the diffraction optical waveguide, and the contact mode of the waveguide and the cover plate is changed through the mutual exclusion effect between the first magnetic coating and the second magnetic coating; the cover plate is restored to an original state, and long-term use of the diffraction optical waveguide is facilitated; meanwhile, the first magnetic coating and the second magnetic coating are divided into a plurality of areas, the refractive indexes of the areas are different, and particularly, the refractive indexes of the coatings of internal and external orthographic projections in the grating structure area are different, so that on one hand, the contact form of the existing grating area and the cover plate is changed to avoid the Newton ring phenomenon, and on the other hand, the structure is simple. The influence of the arrangement of the coating on the total reflection of light in the waveguide is considered, the display uniformity and brightness are improved by limiting the refractive indexes of different areas on the premise of ensuring the display effect of the diffractive optical waveguide, and the visual imaging effect of eyebox is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of augmented reality, and in particular to a diffraction optical waveguide. Background Art

[0002] With the development of key technologies of augmented reality, especially the continuous rise of the concept of the metaverse in the past two years, all walks of life have higher and higher requirements for smart glasses. In order to improve the color display effect of smart glasses and take into account the requirements of lightness and thinness, for diffraction light waveguide components, thinner protective sheet materials are usually selected to replace conventional materials, such as 0.2-0.4mm resin protective sheets or glass protective sheets. Due to the thinness and flexibility of this type of protective sheet itself, it is difficult to achieve compression. While achieving lightweight, it also brings new problems to the waveguide components, such as the overall strength of the waveguide components is poor, easy to bend and deform, and poor drop resistance. Especially during use, the waveguide components are deformed by pressure or collision, which makes them contact with the waveguide sheet and produce Newton rings, thereby affecting the display effect of the diffraction light waveguide. For such problems, how to avoid the occurrence of this phenomenon, prevent the deformation of the protective sheet and ensure the imaging effect in the eyebox is an urgent problem to be solved.

[0003] The present invention is intended to solve the above technical problems and provide a new diffraction optical waveguide to reduce the generation of Newton rings in the waveguide. Summary of the invention

[0004] The embodiment of the present invention provides a diffraction optical waveguide to solve the problems existing in the prior art, and achieves the solution of the Newton ring problem while ensuring the uniformity, brightness and diffraction efficiency in the eyebox, thereby improving the imaging effect of the diffraction optical waveguide.

[0005] The present application claims protection for a diffraction optical waveguide, comprising at least one waveguide sheet and at least one cover plate, wherein the waveguide sheet and the cover plate are stacked, and the waveguide sheet and the cover plate are connected by a connecting member, a grating structure is arranged on a surface of the waveguide sheet facing the cover plate, and the grating structure comprises an in-coupling grating and an out-coupling grating, a first magnetic coating is arranged on a surface of the cover plate facing the waveguide sheet, and a second magnetic coating is arranged on a surface of the waveguide sheet facing the cover plate, the projections of the first magnetic coating and the second magnetic coating at least partially overlap, and the magnetism of the first magnetic coating is opposite to the magnetism of the second magnetic coating. The first magnetic coating and the second magnetic coating are divided into a plurality of regions. When the orthographic projection of the first magnetic coating and / or the second magnetic coating covers the grating structure, the material refractive index of the first magnetic coating and the second magnetic coating within the orthographic projection region is greater than or equal to 2 and not less than the refractive index of the grating structure; the material refractive index of the first magnetic coating and the second magnetic coating outside the orthographic projection region is between 1.0 and 1.5, and is configured not to affect the propagation of light in the optical path; the particle size of the coating particles of the first magnetic coating and the second magnetic coating is configured to be smaller than the spacing between the teeth of the grating structure.

[0006] Further, the second magnetic coating is configured to be disposed around the grating structure.

[0007] Further, the second magnetic coating is configured to cover the grating structure.

[0008] Furthermore, the thickness of the first magnetic coating is smaller than the thickness of the second magnetic coating.

[0009] Furthermore, the area of ​​the first magnetic coating is equal to or unequal to the area of ​​the second magnetic coating.

[0010] Furthermore, the first magnetic coating partially covers or fully covers the surface of the cover plate facing the waveguide plate.

[0011] Furthermore, the first magnetic coating material and the second magnetic coating material are light-transmitting magnetic coating materials.

[0012] Furthermore, the second magnetic coating material is a light-transmitting magnetic coating material, and its refractive index is greater than or equal to 2.

[0013] Optionally, the particle sizes of the coating particles of the first magnetic coating and the second magnetic coating are configured to be smaller than the spacing between the teeth of the grating structure.

[0014] Furthermore, the particle size of the microparticles is 3 nm to 1.2 μm, and can further be 3 nm to 300 nm; or further, can be limited to 20 nm to 80 nm.

[0015] The luminous flux of the optical machine is limited to 1-10 lm to adapt to the propagation of light in the waveguide.

[0016] Furthermore, the thickness of the second magnetic coating material is greater than the height of the coupling-in grating and the coupling-out grating, and less than the height of the connecting member.

[0017] The waveguide sheet may be a resin sheet or a glass sheet; the protection sheet may be a resin sheet or a glass sheet.

[0018] Further, it is practicable to include at least two layers of waveguide sheets and at least one layer of cover plate, wherein the waveguide sheets and the cover plate are stacked, a first magnetic coating is provided on the surface of the cover plate facing the waveguide sheets, a second magnetic coating is provided on the surface of the waveguide sheets facing the cover plate, and a first magnetic coating is provided on the surface of a middle waveguide sheet facing another waveguide sheet, projections of the first magnetic coating and the second magnetic coating at least partially overlap, and the magnetism of the first magnetic coating is different from the magnetism of the second magnetic coating.

[0019] At the same time, the present application seeks protection for a display device, characterized in that it comprises any of the diffraction optical waveguides described above.

[0020] The present application provides a diffraction optical waveguide, which creatively arranges a first magnetic coating and a second magnetic coating with different magnetic properties on the opposite surfaces between the waveguide and the cover plate of the diffraction optical waveguide, and changes the contact mode between the cover plate and the waveguide through the mutual repulsion between the first magnetic coating and the second magnetic coating, so that when the cover plate is deformed by external pressure, the cover plate can be restored to its original state through the repulsive force between the first magnetic coating and the second magnetic coating, thereby reducing the Newton ring phenomenon, facilitating the improvement of the display effect of the diffraction optical waveguide, and improving the durability of use; further, the first magnetic coating and the second magnetic coating are divided into a plurality of regions, each of which has a different refractive index, especially the refractive index of the coating of the inner and outer orthographic projections of the grating structure region is different. On the one hand, the present invention changes the contact mode between the existing grating region and the cover plate to avoid the Newton ring phenomenon, and on the other hand, considering the influence of the coating arrangement on the total reflection of light in the waveguide, how to ensure the display effect of the diffraction optical waveguide. Under the premise of improving the uniformity and brightness of the display by limiting the refractive index of different areas, preventing the introduction of stray light, and ensuring the visual imaging effect in the eyebox; at the same time, according to the difficulty and operability of the coating process, the position, area and thickness of the first magnetic coating and the second magnetic coating in the cover plate and the waveguide are adjusted, and the particle size of the coating particles is controlled to be smaller than the spacing between the teeth of the grating structure to prevent the particles with larger particle sizes from causing optical effects such as diffraction or reflection on the light, and the projection relationship between the first magnetic coating and the second magnetic coating and the refractive index relationship between the projection area of ​​the grating structure are limited, so that the display effect of the diffraction light waveguide is better, stray light is avoided, the uniformity, brightness and diffraction efficiency of the eyebox are improved, and the Newton ring phenomenon is reduced or avoided as much as possible. Through such a structural design, it has significant progress for those skilled in the art. Therefore, the present invention has unexpected technical effects compared with the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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 these drawings without creative work.

[0022] Figure 1 A schematic diagram of a diffractive optical waveguide according to the first embodiment of the present invention;

[0023] Figure 2 A schematic diagram of a diffraction optical waveguide according to the second embodiment of the present invention;

[0024] Figure 3 A schematic diagram of a diffraction optical waveguide according to the third embodiment of the present invention;

[0025] Figure 4 A schematic diagram of a diffraction optical waveguide according to the fourth embodiment of the present invention;

[0026] Figure 5 A schematic diagram of a diffraction optical waveguide according to the fifth embodiment of the present invention;

[0027] Figure 6 A schematic diagram of a diffraction optical waveguide according to Embodiment 6 of the present invention;

[0028] Figure 7 A schematic diagram of a diffraction optical waveguide according to Embodiment 6 of the present invention;

[0029] Figure 8 A schematic diagram of a diffraction optical waveguide according to Embodiment 7 of the present invention;

[0030] Fig. 9 A schematic diagram of a diffractive optical waveguide according to Embodiment 8 of the present invention;

[0031] Fig.10 A schematic diagram of another diffractive optical waveguide according to the first embodiment of the present invention;

[0032] Figure ID:

[0033] 10: cover plate; 20: connector; 30: waveguide plate; 40: out-coupling grating; 50: in-coupling grating; 200: first magnetic coating; 300: second magnetic coating DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0036] The present application provides a diffraction optical waveguide, in which the first embodiment is as follows: Figure 1 , 10 As shown, the optical waveguide 30 comprises at least one layer of waveguide sheet 30 and at least one layer of cover plate 10, wherein the waveguide sheet 30 is stacked with the cover plate 10, and the waveguide sheet 30 and the cover plate 10 are connected by a connecting member 20, and a grating structure is arranged on a surface of the waveguide sheet 30 facing the cover plate 10, wherein the grating structure comprises an in-coupling grating 50 and an out-coupling grating 40, and an optical path region connected by the in-coupling grating 50 and the out-coupling grating 40 is defined as a grating structure region, and a first magnetic coating 200 is arranged on a surface of the cover plate 10 facing the waveguide sheet 30, and a second magnetic coating 300 is arranged on a surface of the waveguide sheet 30 facing the cover plate 10, and the projections of the first magnetic coating 200 and the second magnetic coating 300 overlap, and illustratively, the projections of the first magnetic coating 200 and the second magnetic coating 300 on the waveguide sheet 30 or the cover plate 10 overlap, so that the projections of the first magnetic coating 200 and the second magnetic coating 300 on the waveguide sheet 30 or the cover plate 10 are opposite and opposite to each other on the upper and lower surfaces. It should be arranged that the second magnetic coating 300 is configured to be arranged around the grating structure, and the magnetism of the first magnetic coating 200 is different from the magnetism of the second magnetic coating 300; the first magnetic coating 200 and the second magnetic coating 300 are divided into a plurality of regions, when the orthographic projection of the first magnetic coating 200 and / or the second magnetic coating 300 covers the grating structure, the material refractive index of the first magnetic coating 200 and the second magnetic coating 300 located in the orthographic projection region is greater than or equal to 2 and not less than the refractive index of the grating structure; the material refractive index of the first magnetic coating 200 and the second magnetic coating 300 located outside the orthographic projection region is between 1.0 and 1.5, and is configured not to affect the propagation of light in the optical path; the particle size of the coating particles of the first magnetic coating 200 and the second magnetic coating 300 is configured to be smaller than the spacing between the teeth of the grating structure.

[0037] like Fig.10As shown, the first magnetic coating 200 is divided into a plurality of regions, such as A1, A2, A3, A4, A5 and other sub-regions; the second magnetic coating 300 is divided into a plurality of regions, such as B1, B2, B3, B4, B5 and other sub-regions; when the first magnetic coating 200 and the second magnetic coating 300 cover the grating structure, as shown Fig.10 A2, A4, B2, B4 in the orthographic projection of this part of the sub-area covers the grating structure. In order to consider the effect of the coating setting on the total reflection of light in the waveguide, on the premise of how to ensure the display effect of the diffraction light waveguide, the refractive index of different areas is limited to improve the uniformity and brightness of the display, and to ensure the visual imaging effect in the eyebox. For example, the material refractive index of the first magnetic coating 200 and the second magnetic coating 300 located in the orthographic projection area is greater than or equal to 2, and not less than the refractive index of the grating structure, that is, the A2, A4, B2, B4 sub-areas; the material refractive index of the first magnetic coating 200 and the second magnetic coating 300 located outside the orthographic projection area is between 1.0 and 1.5, and is configured not to affect the propagation of light in the optical path, such as A1, A3, A5; B1, B3, B5 and other sub-areas, to prevent crosstalk of light in the waveguide. It can be known that Fig.10 This is only an example. Of course, limiting the number or area of ​​sub-regions of the first magnetic coating 200 and the second magnetic coating 300 and the area of ​​the orthographic projection region according to the area of ​​the grating structure is also within the scope of the protection scheme of the present application based on the concept of the present invention.

[0038] It can be known that the waveguide sheet can be a resin sheet or a glass sheet; the protection sheet can be a resin sheet or a glass sheet.

[0039] Furthermore, the luminous flux of the optical machine adapted to the diffractive optical waveguide is limited to 1-10 lm to adapt to the propagation of light in the waveguide.

[0040] The present application sets two magnetic coatings with different magnetic properties. Through the mutual repulsion between the coatings, when the cover plate 10 is compressed and bent and deformed, the repulsive force between the coatings can repel each other and restore the cover plate to its original state, thereby changing the contact mode between the cover plate and the waveguide plate and effectively preventing the occurrence of Newton rings. At the same time, based on the uniformity, diffraction efficiency and uniformity requirements within the eyebox, the zoning of different coatings in different areas is controlled, the grating structure area and the non-structure area are zoned and the refractive index of the coatings in different areas is limited. Through such a structural design, unexpected technical effects are achieved.

[0041] Furthermore, the first magnetic coating 200 and the second magnetic coating 300 are divided into a plurality of regions, each region having a different refractive index, especially the coating refractive index of the inner and outer orthographic projections of the grating structure region is different. On the one hand, the present invention changes the contact form between the existing grating region and the cover plate to avoid the Newton ring phenomenon. On the other hand, considering the influence of the coating setting on the total reflection of light in the waveguide, on the premise of how to ensure the display effect of the diffraction light waveguide, the refractive index of different regions is limited to improve the uniformity and brightness of the display, thereby ensuring the visual imaging effect in the eyebox.

[0042] Practically, a black coating is provided on the surface of the connector 20 away from the waveguide, and the periphery of the waveguide is painted black to reduce the crosstalk caused by the external ambient light incident into the waveguide, thereby improving the display effect.

[0043] Further, in embodiment 2, as Figure 2 As shown, the first magnetic coating 200 and the second magnetic coating 300 are staggered with each other, and only the projections of the two overlap, or partially overlap. Through such an arrangement, free space is provided for the area where the coating is set on the waveguide plate 30 and the cover plate 10. Those skilled in the art can determine the area and position for setting the coating according to the difficulty of the process. At the same time, a certain space is reserved for the subsequent setting of the connector 20 on one side of the waveguide, which is convenient for the subsequent waveguide connection and blackening setting, which are all within the scope of protection of the present application without departing from the concept of the present application.

[0044] In practice, further, in embodiment 3, as Figure 3 As shown, the areas of the first magnetic coating 200 and the second magnetic coating 300 are different, which can be defined as the area of ​​the first magnetic coating 200 being larger than the area of ​​the second magnetic coating 300, and the projection of the first magnetic coating being located within the projection area of ​​the second magnetic coating, or alternatively, it can be defined as the area of ​​the first magnetic coating 200 being smaller than the area of ​​the second magnetic coating 300, and the projection of the second magnetic coating being located within the projection area of ​​the first magnetic coating; by adjusting the area sizes of different coatings, the complexity of the process, especially the coating process, or in order to reduce the coating material, save costs and other factors are comprehensively considered.

[0045] It can be known that in the fourth embodiment, the thickness of the first magnetic coating 200 and the second magnetic coating 300 can be different. For the second magnetic coating 300, the minimum thickness must be higher than the height of the coupling-in grating and the coupling-out grating, which can be limited to between 1 μm and 0.2 mm. Figure 4As shown, it is operably defined that the thickness of the first magnetic coating 200 is smaller than that of the second magnetic coating 300. By limiting the second magnetic coating 300 with a higher thickness to bear the external pressure, on the one hand, it can effectively alleviate the greater pressure on the cover during the compression process, and has a stronger pressure bearing capacity, so that the cover can quickly restore its deformation and effectively reduce the Newton ring phenomenon; on the other hand, in the process of contact between the cover and the second magnetic coating, the cover can be preferentially made to contact the second magnetic coating rather than the grating structure, so that the contact between the cover and the grating structure can be effectively reduced, the cover is prevented from compressing and damaging the grating structure in the waveguide, and the service life of the diffraction optical waveguide is increased.

[0046] It can be known that in embodiments 1 to 4, combined with Figure 1-4 The cover plate 10 includes a plurality of first magnetic coating 200 regions, such as two or more first magnetic coating regions. The first magnetic coating 200 partially covers the surface of the cover plate 10 facing the waveguide sheet 30 .

[0047] Furthermore, as in Example 5, considering the operability and convenience of the process, Figure 5 The first magnetic coating 200 completely covers the surface of the cover plate 10 facing the waveguide plate 30. Optionally, the first magnetic coating 200 is defined as a light-transmissive magnetic material, such as a transparent magnetic material, etc., so as to further enhance the mutual repulsion between the first magnetic coating and the second magnetic coating.

[0048] It can be implemented that in Example 5, for the limiting conditions such as the thickness and relative position relationship of the first magnetic coating and the second magnetic coating, the limiting conditions of the relevant thickness and relative position relationship in Examples 1 to 4 can be adopted, which are not repeated here. In the technical scheme of Example 5, the embodiments such as the limiting conditions of the thickness and relative position relationship of the first magnetic coating and the second magnetic coating are all within the protection scope of this application.

[0049] Further, optionally, the present application provides Example 6, such as Figure 6 As shown, it is defined as comprising at least one layer of waveguide sheet 30 and at least one layer of cover plate 10, the waveguide sheet 30 is stacked with the cover plate 10, and the waveguide sheet 30 and the cover plate 10 are connected by a connecting member 20, a grating structure is arranged on the surface of the waveguide sheet 30 facing the cover plate 10, the grating structure comprises a coupling-in grating 50 and a coupling-out grating 40, a first magnetic coating 200 is arranged on the surface of the cover plate 10 facing the waveguide sheet 30, and a second magnetic coating 300 is arranged on the surface of the waveguide sheet 30 facing the cover plate 10, the projections of the first magnetic coating 200 and the second magnetic coating 300 overlap, so that they are arranged oppositely on the upper and lower surfaces, the second magnetic coating 300 is configured to cover the grating structure, and the magnetic properties of the first magnetic coating 200 are different from those of the second magnetic coating 300.

[0050] Practically, the first magnetic coating 200 and the second magnetic coating 300 are selected from light-transmitting magnetic materials, such as iron oxide film, cadmium zinc germanium phosphide (CZGP), ferrite / zinc oxide (Fe3O4 / ZnO) nanocomposite materials, silver chromate (AgCrO2), iron-cobalt alloy and insulating material aluminum fluoride mixed new materials, etc.

[0051] In order to improve the imaging effect of the diffraction optical waveguide and prevent the coating from affecting the uniformity, brightness, etc. of the waveguide, the particle size range of the magnetic particles of the first magnetic coating 200 and the second magnetic coating 300 can be limited to 3nm to 1.2μm. Furthermore, considering the size of the grating structure and the effect of the magnetic coating on the grating diffraction efficiency when the magnetic coating is set, to prevent the adverse effect of larger coating particles on the imaging, the particle size of the particles can be controlled to be smaller than the spacing between the teeth of the grating structure, such as limiting the particle size range of the particles to 3nm to 300nm, or even, controlled to be within the range of 3nm to 120nm, or 10nm to 150nm, 10nm to 200nm, or a smaller range such as 20nm to 80nm.

[0052] Therefore, based on the principle of optical imaging, higher requirements are placed on the particle size of the coating particles. The particle size is controlled to be smaller than the spacing between the teeth of the grating structure to prevent larger particles from producing additional optical effects on the light and introducing stray light that is not conducive to the imaging effect. It can be implemented by controlling the particle size to be below 300nm, or below 200nm, or even below 120nm, or below 80nm to improve the uniformity and brightness of the light output.

[0053] Furthermore, the second magnetic material may be limited to have a higher refractive index, such as a refractive index greater than 2.3, so as to improve the diffraction effect. There is no requirement for the refractive index of the first magnetic material, as long as it meets the optical imaging conditions.

[0054] In practice, when the second magnetic coating 300 is configured to cover the grating structure, it is optional to define a plurality of first magnetic coating 200 regions on the surface of the cover plate 10, such as Figure 6 Or further, the first magnetic coating 200 fully covers the surface of the cover plate 10, and the coating covers the entire surface of the cover plate 10, such as Figure 7 As shown, of course, the height of the second magnetic coating 300 can be determined based on the height of the grating structure, and the height of the second magnetic coating 300 can be limited to be equal to or greater than the height of the grating structure, or the height of the second magnetic coating 300 can be much greater than the height of the grating structure. The height relationship between the first magnetic coating 200 and the second magnetic coating 300 can be appropriately adjusted according to the actual Newton ring phenomenon, which is not limited in detail here.

[0055] Further, further improvements to Example 6 are as follows: Figure 8 In the seventh embodiment, a first magnetic coating 200 is provided on the surface of the cover plate 10 facing the waveguide plate 30, and a second magnetic coating 300 is provided on the surface of the waveguide plate 30 facing the cover plate 10. The projections of the first magnetic coating 200 and the second magnetic coating 300 at least partially overlap, and the second magnetic coating only covers the grating structure area. The second magnetic material has a higher refractive index, such as a refractive index greater than 2.3, and the refractive index of the first magnetic material can be sufficient to meet the optical imaging conditions.

[0056] It is feasible, such as Fig. 9 Embodiment 8: A diffraction optical waveguide is claimed, comprising at least two layers of waveguide sheets 30 and at least one layer of cover plate 10, wherein the waveguide sheet 30 is stacked with the cover plate 10, and the waveguide sheet 30 and the cover plate 10 are connected by a connector 20, a grating structure is arranged on a surface of the waveguide sheet 30 facing the cover plate 10, the grating structure comprises a coupling-in grating 50 and a coupling-out grating 40, and an optical path region connected by the coupling-in grating 50 and the coupling-out grating 40 is defined as a grating structure region, a first magnetic coating 200 is arranged on a surface of the cover plate 10 facing the waveguide sheet 30, a second magnetic coating 300 is arranged on a surface of the waveguide sheet 30 facing the cover plate 10, and a first magnetic coating 200 is arranged on a surface of a middle waveguide sheet facing another waveguide sheet, the projections of the first magnetic coating 200 and the second magnetic coating 300 at least partially overlap, so that they are arranged opposite to each other on the upper and lower surfaces, and the magnetic properties of the first magnetic coating 200 are different from those of the second magnetic coating 300.

[0057] For one embodiment in the eighth embodiment, the second magnetic coating 300 is configured to surround the grating structure, or alternatively, the second magnetic coating can cover the grating structure area, or the first magnetic coating partially or completely covers the surface of the cover plate 10 facing the waveguide plate. The layout of the aforementioned embodiments one to seven can also be used in the eighth embodiment. The present invention does not make further limitations on this, and different coating combinations can be made, all of which belong to the embodiments of the present application.

[0058] In some embodiments of the present application, the grating structure also includes a turning grating, and the grating structure area at this time is defined as the area of ​​the light path connected to the locations of the coupling-in grating, the turning grating, and the coupling-out grating. Of course, in other embodiments, the grating structure may also include other functional gratings, such as a recycling grating, etc., and the grating structure area at this time is defined as the area where the grating structure is located and the area of ​​the light path connected to the locations of the gratings in the grating structure.

[0059] At the same time, the present application seeks protection for a display device comprising the diffractive optical waveguide described in any one of the aforementioned embodiments.

[0060] The present application provides a diffraction optical waveguide, which creatively arranges a first magnetic coating and a second magnetic coating with different magnetic properties on the opposite surfaces between the waveguide and the cover plate of the diffraction optical waveguide, and changes the contact mode between the cover plate and the waveguide through the mutual repulsion between the first magnetic coating and the second magnetic coating, so that when the cover plate is deformed by external pressure, the cover plate can be restored to its original state through the repulsive force between the first magnetic coating and the second magnetic coating, thereby improving the display effect of the diffraction optical waveguide and improving the durability of use; further, the first magnetic coating and the second magnetic coating are divided into a plurality of regions, each of which has a different refractive index, especially the refractive index of the coating of the inner and outer orthographic projections of the grating structure region is different. On the one hand, the present invention changes the contact mode between the existing grating region and the cover plate to avoid the Newton ring phenomenon, and on the other hand, considering the design of the coating The influence of the total reflection of light in the waveguide is controlled. Under the premise of how to ensure the display effect of the diffraction light waveguide, the uniformity and brightness of the display are improved by limiting the refractive index of different areas to ensure the visual imaging effect in the eyebox; at the same time, according to the difficulty and operability of the coating process, the position, area and thickness of the first magnetic coating and the second magnetic coating in the cover plate and the waveguide are adjusted, and the projection relationship between the first magnetic coating and the second magnetic coating is limited. Furthermore, the particle size of the coating particles is limited to be configured to be smaller than the distance between the teeth of the grating structure to prevent the influence of particles with larger particle sizes on the light, so that the display effect of the diffraction light waveguide is better, and the occurrence of Newton's ring phenomenon is reduced or avoided as much as possible. Through such a structural design, it is a significant improvement for those skilled in the art. Therefore, the present invention has unexpected technical effects compared with the prior art.

[0061] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A diffractive optical waveguide, characterized in that: The invention comprises at least one layer of waveguide sheet and at least one layer of cover plate, wherein the waveguide sheet and the cover plate are stacked and connected by a connecting member, a grating structure is arranged on a surface of the waveguide sheet facing the cover plate, the grating structure comprises an in-coupling grating and an out-coupling grating, a first magnetic coating is arranged on a surface of the cover plate facing the waveguide sheet, and a second magnetic coating is arranged on a surface of the waveguide sheet facing the cover plate, the projections of the first magnetic coating and the second magnetic coating at least partially overlap, and the magnetism of the first magnetic coating is different from that of the second magnetic coating; the first magnetic coating and the second magnetic coating are divided into a plurality of regions, when the orthographic projection of the first magnetic coating and / or the second magnetic coating covers the grating structure, the material refractive index of the first magnetic coating and the second magnetic coating located in the orthographic projection region is greater than or equal to 2 and not less than the refractive index of the grating structure; the material refractive index of the first magnetic coating and the second magnetic coating located outside the orthographic projection region is between 1.0 and 1.5, and they are configured not to affect the propagation of light in the optical path.

2. The diffractive optical waveguide according to claim 1, characterized in that: The second magnetic coating is configured to surround the grating structure.

3. The diffractive optical waveguide according to claim 1, characterized in that: The second magnetic coating is configured to cover the grating structure.

4. The diffractive optical waveguide according to claim 2 or 3, characterized in that: The thickness of the first magnetic coating layer is smaller than that of the second magnetic coating layer; and the particle sizes of the coating particles of the first magnetic coating layer and the second magnetic coating layer are configured to be smaller than the spacing between the teeth of the grating structure.

5. The diffractive optical waveguide according to claim 2 or 3, characterized in that: The first magnetic coating material and the second magnetic coating material are light-transmitting magnetic coating materials.

6. The diffractive optical waveguide according to claim 4, characterized in that: The first magnetic coating partially covers or fully covers the surface of the cover plate facing the waveguide.

7. The diffractive optical waveguide according to claim 5, characterized in that: The particle size of the microparticles may be 3 nm to 300 nm.

8. The diffractive optical waveguide according to claim 4, characterized in that: The thickness of the second magnetic coating material is greater than the height of the coupling-in grating and the coupling-out grating, and less than the height of the connecting member.

9. The diffractive optical waveguide according to claim 4, characterized in that: The invention comprises at least two layers of waveguide sheets and at least one layer of cover plate, wherein the waveguide sheets and the cover plate are stacked, a first magnetic coating is arranged on the surface of the cover plate facing the waveguide sheets, a second magnetic coating is arranged on the surface of the waveguide sheets facing the cover plate, and a first magnetic coating is arranged on the surface of a middle waveguide sheet facing another waveguide sheet, projections of the first magnetic coating and the second magnetic coating at least partially overlap, and the magnetism of the first magnetic coating is different from the magnetism of the second magnetic coating.

10. A display device, characterized in that: The diffractive optical waveguide comprises the diffractive optical waveguide as claimed in any one of claims 1 to 9.

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