A high-strength cover plate for an ar diffractive optical waveguide

Abstract

The utility model provides a kind of high-strength cover plate for AR diffraction light waveguide, including cover plate base and antireflection coating layer;The outer surface of the cover plate base is provided with the antireflection coating layer;The antireflection coating layer adopts the hierarchical alternate film layer consisting of niobium pentoxide film layer and silicon dioxide film layer.Cover plate base outer surface The antireflection coating layer provided with adopts the hierarchical alternate film layer consisting of niobium pentoxide film layer and silicon dioxide film layer, so that the antireflection coating layer has compression resistance, to improve the mechanical strength of the cover plate for AR diffraction light waveguide.

Description

Technical Field

[0001] This utility model belongs to the field of AR technology, specifically relating to a high-strength cover plate for AR diffractive waveguides. Background Technology

[0002] Augmented Reality (AR) technology refers to providing users with additional information in the real world through certain technical means (i.e., "enhancement"). This technology organically integrates images from the virtual world with scenes from the real world, providing users with richer information and an immersive experience by deeply integrating the calculated information with the real world.

[0003] Augmented reality (AR) technology can be implemented through many hardware platforms, among which wearable AR devices, namely AR glasses, offer the most immersive experience. This type of hardware is a simple pair of glasses that guides light into the eye through microstructures on the lens surface. This hardware implementation is the most convenient and efficient, and is the mainstream technology for AR. The purpose of AR glasses lenses is to guide images from the imaging device into the eye through the lenses. Diffractive waveguide solutions are a mainstream technical approach, such as... Figure 1 As shown, a diffractive waveguide includes a waveguide substrate, a coupling grating, and a coupling grating. The coupling grating and the coupling grating are disposed on the waveguide substrate, and their basic principle is as follows: Figure 1 As shown, the light output from the optomechanical system 1 (imaging device) is coupled into the waveguide substrate 2 by the coupling grating 3. It propagates in the waveguide substrate 2 by total internal reflection. Whenever it encounters the coupling grating 4, a portion of the light is coupled out. The coupled-out light (the solid line in the direction of the human eye in the figure) enters the human eye, so that the same image as the output of the optomechanical system 1 can be seen. At the same time, the human eye can see the real world scene (the dashed line in the direction of the human eye in the figure). The superposition of the two parts can realize the function of augmented reality.

[0004] The existing methods for fabricating diffractive optical waveguides are generally as follows:

[0005] 1. Prepare a grating master with a preset grating structure.

[0006] 2. The grating structure of the grating master is transferred to the soft film substrate using a nanoimprinting process to obtain a soft film with a reverse grating structure.

[0007] Specifically, an imprinting adhesive is uniformly spin-coated onto the grating master plate, and a soft film substrate is bonded to the grating master plate. Pressure is applied to fill the grating structure of the grating master plate with the imprinting adhesive, resulting in an inverse structure of the grating structure on the imprinting adhesive. The grating structure is then cured and demolded using ultraviolet light, and the imprinting adhesive with the inverse structure of the grating structure is transferred to the soft film substrate to obtain a soft film with the inverse structure of the grating structure.

[0008] 3. The inverse structure of the grating structure on the soft film is transferred onto the waveguide wafer using a nanoimprinting process to obtain a waveguide wafer with a grating structure.

[0009] Specifically, a mold adhesive is spin-coated onto a waveguide wafer, and a soft film with an inverse grating structure is bonded to the mold adhesive on the waveguide wafer. Pressure is applied to fill the inverse grating structure of the soft film with the mold adhesive, thus obtaining a grating structure on the mold adhesive. Ultraviolet light is used for curing and demolding to separate the soft film with the inverse grating structure from the mold adhesive with the grating structure, resulting in a waveguide wafer with a grating structure.

[0010] 4. The waveguide wafer with the grating structure is cut according to the finished waveguide shape to obtain waveguide wafer units.

[0011] 5. Based on the layered structure of the finished waveguide (consisting of at least one cover plate and at least one waveguide wafer unit), bonding operation is performed at the edge area between the cover plate and the waveguide wafer unit using bonding adhesive, or bonding operation is performed at the edge area between the waveguide wafer units to obtain a waveguide bonding structure.

[0012] 6. The end face of the waveguide bonding structure is sealed with light-shielding adhesive to obtain the finished diffractive waveguide.

[0013] To increase the light transmittance and reduce the light reflectance of a diffractive waveguide, an anti-reflection coating is currently applied to the cover plate. However, applying this coating reduces the mechanical strength of the cover plate for the following reasons:

[0014] (1) Material interface damage: Ar needs to be used before coating. + O2 plasma cleaning of the cover plate surface leads to the breakage of silicon-oxygen bonds and the formation of nanoscale pits on the cover plate surface.

[0015] (2) Thermal stress damage: Excessive coating temperature or excessive cooling rate will affect the cover plate.

[0016] (3) Magnification of structural defects: magnify the micro-cracks on the surface of the cover plate. Utility Model Content

[0017] In order to overcome the shortcomings of the prior art, this utility model provides a high-strength cover plate for AR diffractive waveguides.

[0018] This utility model is achieved through the following technical solution:

[0019] This utility model provides a high-strength cover plate for AR diffractive waveguides, including a cover plate substrate and an anti-reflection coating layer;

[0020] The anti-reflective coating layer is disposed on the outer surface of the cover plate substrate;

[0021] The antireflective coating is a layered alternating layer composed of niobium pentoxide and silicon dioxide layers.

[0022] Furthermore, the cover plate substrate is made of microcrystalline glass.

[0023] Furthermore, it also includes a pressure-resistant membrane layer;

[0024] The pressure-resistant membrane layer is disposed between the cover plate substrate and the antireflective and anti-reflective membrane layer.

[0025] Furthermore, it also includes a pressure-resistant membrane layer;

[0026] The pressure-resistant film layer is disposed on the outer surface of the antireflective and anti-reflective coating layer.

[0027] Furthermore, the pressure-resistant membrane layer is made of one or more of silicon nitride, silicon carbide, or aluminum oxide.

[0028] Furthermore, the pressure-resistant membrane layer adopts a single-layer structure or a multi-layer structure;

[0029] Among them, the multi-layer structure adopts a multi-layer structure with different materials for each layer or a multi-layer structure with alternating material layers.

[0030] Furthermore, the thickness of the antireflective coating is 200-300 nm.

[0031] Furthermore, the thickness of the pressure-resistant membrane layer is 50-100 nm.

[0032] Compared with the prior art, the technical solution of this utility model has the following beneficial effects:

[0033] This invention provides a high-strength cover plate for AR diffractive waveguides, comprising a cover plate substrate and an antireflection coating layer. The antireflection coating layer is disposed on the outer surface of the cover plate substrate, and the antireflection coating layer is composed of alternating layers of niobium pentoxide and silicon dioxide. The alternating layers of niobium pentoxide and silicon dioxide on the outer surface of the cover plate substrate give the antireflection coating layer compressive strength, thereby improving the mechanical strength of the cover plate used for AR diffractive waveguides. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A schematic diagram illustrating the basic principle of existing diffractive optical waveguides;

[0036] Figure 2 A schematic diagram of a first example structure of a high-strength cover plate for an AR diffractive waveguide provided by this utility model;

[0037] Figure 3 A schematic diagram of a second example structure of the high-strength cover plate for AR diffractive waveguide provided by this utility model;

[0038] Figure 4 This is a schematic diagram of a third example structure of a high-strength cover plate for an AR diffractive waveguide provided by this utility model.

[0039] Figure 5 This is a comparison chart of test data from a drop ball experiment conducted on the high-strength cover plate for AR diffractive waveguides provided by this invention and existing cover plates.

[0040] Among them, 1-optical mechanism, 2-waveguide substrate, 3-coupled grating, 4-coupled grating, 5-cover plate substrate, 6-antireflection and anti-reflection coating, 7-pressure-resistant coating. Detailed Implementation

[0041] The technical solution of this utility model will be clearly and completely described below with reference to its embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0042] In this document, the terms "first," "second," and other similar words are not intended to imply any order, quantity, or importance, but are merely used to distinguish different elements. The terms "one," "a," and other similar words are not intended to indicate the existence of only one of the stated things, but rather that the description refers only to one of the stated things, which may have one or more. The terms "comprising," "including," and other similar words are intended to indicate a logical relationship, not a spatial relationship. For example, "A includes B" means that logically B belongs to A, not that spatially B is located inside A. Furthermore, the meanings of the terms "comprising," "including," and other similar words should be considered open-ended, not closed. For example, "A includes B" means that B belongs to A, but B does not necessarily constitute all of A; A may also include other elements such as C, D, and E.

[0043] In this document, the terms "embodiment," "this embodiment," "preferred embodiment," and "one embodiment" do not imply that the description applies only to one specific embodiment, but rather that such description may also be applicable to one or more other embodiments. Those skilled in the art will understand that any description made herein relating to one embodiment can be substituted, combined, or otherwise incorporated with the descriptions in one or more other embodiments. Such substitutions, combinations, or other incorporations resulting in new embodiments are readily conceived by those skilled in the art and fall within the protection scope of this utility model.

[0044] In this description, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] like Figure 2 As shown, this utility model provides a high-strength cover plate for AR diffractive waveguides, including a cover plate substrate 5 and an antireflection coating layer 6.

[0046] An antireflective coating 6 is provided on the outer surface of the cover plate substrate 5. The antireflective coating can be deposited on the outer surface of the cover plate substrate using existing vacuum coating processes.

[0047] The thickness of the antireflective coating is controlled at 200-300nm.

[0048] The antireflective coating uses alternating layers of niobium pentoxide and silicon dioxide. For example, the antireflective coating may consist of niobium pentoxide, silicon dioxide, niobium pentoxide, silicon dioxide, niobium pentoxide, silicon dioxide, and so on. The niobium pentoxide and silicon dioxide layers can be made using existing coating materials.

[0049] The antireflection coating layer on the outer surface of the cover plate substrate is composed of alternating layers of niobium pentoxide and silicon dioxide, which gives the antireflection coating layer compressive strength, thereby improving the mechanical strength of the cover plate used for AR diffraction waveguides.

[0050] The cover plate substrate is preferably made of glass-ceramic, whose numerous hard crystalline phases endow it with higher intrinsic hardness and flexural strength. Through a controlled crystallization process, a large number of nanoscale, randomly distributed crystals are grown in situ within the glass matrix, forming a unique "crystal-glass" composite structure. This structure fundamentally alters crack propagation behavior, significantly dissipating fracture energy through various mechanisms such as crack deflection, bridging, and branching, resulting in excellent mechanical properties in terms of toughness and impact resistance. Therefore, using glass-ceramic as the cover plate substrate further enhances the mechanical strength of the cover plate used in AR diffraction waveguides.

[0051] As a preferred embodiment, the high-strength cover plate for AR diffractive waveguides provided by this utility model also includes a pressure-resistant film layer.

[0052] The pressure-resistant membrane layer 7 can be disposed between the cover plate substrate 5 and the anti-reflective coating layer 6 (e.g.) Figure 3 (As shown). At this time, the pressure-resistant membrane layer serves as a bonding layer between the antireflective and anti-reflective membrane layer and the cover plate substrate, and can improve the overall mechanical strength of the entire membrane layer on the cover plate substrate, preventing the membrane layer from cracking or falling off under pressure.

[0053] The pressure-resistant membrane layer 7 can also be disposed on the outer surface of the antireflective and anti-reflective membrane layer 6 (e.g., Figure 4 (As shown). At this time, the pressure-resistant membrane layer acts as an outer protective layer to resist external pressure.

[0054] The pressure-resistant film layer can be applied between the cover plate substrate and the antireflective coating layer or on the outer surface of the antireflective coating layer using existing magnetron sputtering technology and sol-gel method.

[0055] The pressure-resistant film obtained by magnetron sputtering is dense, has good adhesion, high uniformity, and controllable purity. The sol-gel method allows for large-area deposition of the pressure-resistant film with simple equipment and low cost.

[0056] The thickness of the pressure-resistant membrane should be controlled between 50-100 nm. If the pressure-resistant membrane is too thin, the protective strength of the pressure resistance will be insufficient, while if the pressure-resistant membrane is too thick, it will introduce greater internal stress and reduce the adhesion of the pressure-resistant membrane.

[0057] The pressure-resistant membrane layer can be made of one or more of the existing silicon nitride, silicon carbide, or aluminum oxide. These materials have excellent properties in terms of hardness and toughness, and their coefficients of thermal expansion match those of the cover plate substrate, thereby reducing internal stress caused by temperature changes and preventing the membrane layer from cracking or peeling off.

[0058] The pressure-resistant membrane can be a single-layer or multi-layer structure.

[0059] The single-layer structure can be composed of one of the above-mentioned materials: silicon nitride, silicon carbide, or aluminum oxide.

[0060] The multi-layer structure can include a multi-layer structure where each layer has a different material or a multi-layer structure with alternating material layers. For a multi-layer structure where each layer has a different material, an example is as follows: the pressure-resistant film layer consists of a three-layer structure, which sequentially includes a silicon carbide film layer, a silicon nitride film layer, and an aluminum oxide film layer. For a multi-layer structure with alternating material layers, an example is as follows: the pressure-resistant film layer consists of alternating layers of silicon carbide and silicon nitride films.

[0061] The following performance tests were conducted on the high-strength cover plate for AR diffractive waveguides provided by this utility model:

[0062] (1) Optical performance:

[0063] Instrument: A UV-Vis spectrophotometer was used for testing.

[0064] Test results: Within the wavelength range of 450-650nm, the maximum reflectivity is <1%.

[0065] (2) Mechanical properties and durability:

[0066] Adhesion: According to the cross-cut adhesion test, a rating of 5B is considered excellent.

[0067] ① Visually inspect the cover plate before the experiment to ensure that there are no scratches, marks, detachments or other abnormalities;

[0068] ② Drill 10×10 1mm×1mm test grids on the inner and outer surfaces of the cover plate;

[0069] ③ Firmly adhere the test grid with 3M tape, and squeeze the tape with an eraser or glue stick to remove air bubbles. Hold one end of the tape and pull it off within 0.5 seconds at a 60° angle to the opposite direction of the tape application. Repeat this process 3 times. Each test result shows that the cover plate adhesion can reach level 5B.

[0070] Hardness: Pencil hardness test; pressure-resistant membrane assemblies are generally required to have a hardness of ≥4H.

[0071] Place the cover plate on the laboratory bench. Hold a pencil at a 45° angle to the bench and scratch the surface of the cover plate with a force of 750g ± 5g. Scratch the surface of the cover plate 3-5mm at a uniform speed using the pencil lead, repeating the scratching 5 times. No scratches were found on the surface of the cover plate during each hardness test, meeting the 4H requirement.

[0072] Abrasion resistance: steel wool friction test.

[0073] ① Before testing, check the appearance and function of the cover to ensure it is in good condition;

[0074] ② Rub the cover plate surface with steel wool under load (movement direction along the steel wool fiber direction) at a test frequency of 40 times / min and a stroke of about 30mm. The steel wool should not detach from the cover plate. Rub for 1000 times. No scratches were found on the cover plate surface during each friction test, indicating excellent wear resistance.

[0075] Impact resistance: Drop ball test to evaluate the membrane's ability to withstand instantaneous pressure.

[0076] ① Place the cover plate on the test fixture, and fix the test fixture on a rigid plane;

[0077] ② Use a 16g steel ball at the specified test point and set the required drop height to conduct a drop impact test;

[0078] ③ Use a guide tube to ensure the correct landing point.

[0079] Six high-strength cover plates of this invention and six existing cover plates were selected for drop ball tests. The test results are as follows: Figure 5 As shown in the figure, the high-strength cover plate of this utility model has a greater resistance to falling ball impact energy and improved falling ball impact performance compared with the existing cover plate.

[0080] Environmental reliability: High and low temperature cycling tests and damp heat tests were conducted to verify the stability of the membrane layer under different environments. The test results showed that the cover plate had good stability.

[0081] The above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art can still make modifications or equivalent substitutions to the specific implementation of this utility model. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this utility model are within the protection scope of the claims of this utility model pending approval.

Claims

1. A high-strength cover plate for AR diffractive waveguides, characterized in that, This includes the cover plate substrate, the antireflective coating layer, and the pressure-resistant coating layer; The anti-reflective coating layer is disposed on the outer surface of the cover plate substrate; The antireflective coating is a layered alternating layer composed of niobium pentoxide and silicon dioxide layers. The cover plate substrate is made of microcrystalline glass. The pressure-resistant film layer is disposed between the cover plate substrate and the antireflective coating layer, or the pressure-resistant film layer is disposed on the outer surface of the antireflective coating layer.

2. The high-strength cover plate for AR diffractive waveguides according to claim 1, characterized in that, The pressure-resistant membrane layer is made of one or more of silicon nitride, silicon carbide, or aluminum oxide.

3. The high-strength cover plate for AR diffractive waveguides according to claim 1, characterized in that, The pressure-resistant membrane layer adopts a single membrane layer structure or a multi-membrane layer structure; Among them, the multi-layer structure adopts a multi-layer structure with different materials for each layer or a multi-layer structure with alternating material layers.

4. The high-strength cover plate for AR diffractive waveguides according to claim 1, characterized in that, The thickness of the antireflective coating is 200-300 nm.

5. The high-strength cover plate for AR diffractive waveguides according to claim 1, characterized in that, The thickness of the pressure-resistant membrane is 50-100 nm.

Images