Systems and methods for scratch-resistant, wear-resistant, and low-reflectivity optical coatings

Abstract

A system method and protective coating for a transparent panel, particularly beneficial to a transparent panel made from the system and coating that covers a digital display. The protective coating includes an adhesion layer formed on a surface of the transparent panel, a stress grading interlayer formed over the adhesion layer, a protective layer formed over the stress grading interlayer, and an anti-reflection layer formed over the protective layer. The invention also provides a sputtering system for manufacturing the protective coating.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 287,024, filed on December 7, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to coatings for protecting transparent panels, especially transparent panels used in electronic devices. Background Art

[0004] With the widespread popularity of mobile devices with optical displays such as mobile phones, smart watches, and VR glasses, there is an increasing demand to protect these devices from damage during use (thus damaging their display effects). The transparent panel (glass or plastic) used to protect the optical display needs to be optically transparent, have high transmittance, low reflectivity, and be scratch and wear resistant. A coating that does not degrade the optical performance of the panel can be used to enhance the scratch and wear resistance of the panel. Summary of the invention

[0005] The following summary of the invention is intended to provide a basic understanding of certain aspects and features of the present invention. The summary of the invention is not an exhaustive overview of the present invention and is therefore not intended to specifically list the key or important elements of the present invention or to define the scope of the present invention. Its sole purpose is to present some concepts of the present invention in a simplified form as a preface to a more detailed description below.

[0006] The disclosed embodiments provide coatings made of various material layers that work together to enhance the scratch and abrasion resistance of transparent panels. These coatings do not degrade the optical performance of the transparent panel and may even enhance its optical performance. When applied to a transparent panel, the optical performance is improved because the transmittance through the protective film and panel is higher than the transmittance through the panel without the film. This is at least in part due to the inclusion of an anti-reflective layer in the stack of protective coatings. Embodiments of an apparatus for efficiently coating a transparent substrate are also disclosed.

[0007] The disclosed embodiments provide a transparent protective coating having an adhesion layer, a stress grading layer, a protective layer, and an anti-reflective layer. In the disclosed embodiments, the adhesion layer comprises an oxide-containing layer having a refractive index n less than 1.65. The adhesion layer does not contain nitrogen, and in some embodiments, the refractive index is set to be less than 1.5. The stress grading interlayer is composed of an oxide-containing layer having a refractive index n lower than that of the protective layer. The thickness of the protective layer is at least three times the thickness of the stress grading interlayer, and the refractive index of the protective layer is higher than the refractive index of the stress grading interlayer. The anti-reflective layer comprises a plurality of sublayers, wherein at least one sublayer has a higher refractive index than the protective layer, and at least one sublayer has a lower refractive index than the protective layer.

[0008] The disclosed embodiments also provide a transparent coating capable of forming an anti-reflective coating with improved lifetime on a plastic substrate. A diffusion barrier layer is first deposited on the plastic substrate. The diffusion barrier layer inhibits the rise of substrate moisture to the surface of the anti-reflective film, resulting in a reduction in the optical properties of the material. The diffusion barrier layer has a low refractive index, for example, below 1.65, by including a relatively high amount of oxygen and a relatively low amount of nitrogen. In the disclosed embodiments, the barrier layer is made of SiAlOxNy, with a low amount of Al and a low amount of N, so that the resulting refractive index is below 1.65 or even below 1.55.

[0009] The disclosed embodiments also provide a method for manufacturing a protective coating, comprising the following steps: introducing a transparent substrate into a vacuum environment; exposing the substrate to a plasma so that ion species bombard the top surface of the substrate; forming an adhesion layer by sputtering a silicon target; forming a stress grading layer on the adhesion layer by sputtering a SiAl target while injecting a mixture of oxygen and nitrogen into the sputtering plasma; forming a protective layer on the stress grading layer by sputtering the SiAl target while injecting a second mixture of oxygen and nitrogen into the sputtering plasma; and forming an anti-reflection layer on the protective layer by sputtering the SiAl target while injecting a third mixture of oxygen and nitrogen into the sputtering plasma.

[0010] The present invention provides a sputtering system, comprising: a vacuum chamber, in which a plurality of sputtering stations are arranged, with unimpeded free fluid flow between the sputtering stations, each sputtering station having two sputtering sources, the targets of the two sputtering sources being made of the same material, and each sputtering station having a gas injection manifold located between the two sputtering sources; a gas delivery manifold, which delivers a first gas and a second gas to each gas injection manifold; a controller, which independently controls the ratio of the first gas and the second gas delivered to each gas injection manifold; a feedback loop, which measures the gas flow in each gas injection manifold and sends a corresponding signal to the controller; a loading station (loadlock) mounted on the vacuum chamber; and a gate valve sealed between the vacuum chamber and the loading station. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Other aspects and features of the present invention will become apparent from the detailed description which proceeds with reference to the following drawings.It should be understood that the detailed description and drawings provide various non-limiting examples of various embodiments of the invention, which is defined by the appended claims.

[0012] The accompanying drawings are incorporated into and constitute a part of this specification and are used to illustrate embodiments of the present invention and, together with the description, are used to explain and illustrate the principles of the present invention. The accompanying drawings are intended to illustrate the main features of the exemplary embodiments in a diagrammatic manner. The accompanying drawings are not intended to depict every feature of the actual embodiments or the relative sizes of the depicted elements and are not drawn to scale.

[0013] Figure 1 schematically depicts a cross-section of a protective coating showing the layers according to one embodiment;

[0014] Figure 2 schematically depicts a cross-section of a protective coating showing the layers according to another embodiment;

[0015] Figure 3 schematically depicts one embodiment of a linear system for making the coatings disclosed herein; and

[0016] Figure 4 One embodiment of a circulation-type system for making the coatings disclosed herein is schematically depicted. DETAILED DESCRIPTION

[0017] Various embodiments or combinations thereof may be used for different applications or to achieve different benefits. Depending on the results to be achieved, the various features disclosed herein may be utilized in part or in whole, and may be used alone or in combination with other features to achieve a balanced advantage between requirements and limitations. Therefore, certain benefits will be emphasized with reference to different embodiments, but are not limited to the disclosed embodiments. That is, the features disclosed herein are not limited to the embodiments in which they are described, but may be "mixed and matched" with other features and incorporated into other embodiments.

[0018] In the disclosed embodiment, the layers of the coating are formed using a sputtering process. Generally, the sputtering process itself is well known and uses a target made of a material to be deposited on a substrate (here a transparent panel). The target is bombarded to sputter the material from the target, and then the material travels and falls on the substrate. Sputtering can be performed in a so-called "poisoning mode", in which the surface of the target is "poisoned" by interacting with the gas near the target, or sputtering can also be performed in a metal mode, in which the surface of the target is purely kept as the original material of the target. For example, when oxygen is used in the sputtering chamber, a high oxygen flow rate may cause the surface of the target to oxidize and thus sputter as an oxide. Conversely, in the metal mode, pure target material is sputtered, and if oxidation is required, it can be done by introducing the coated substrate into an oxygen environment at a later stage of the process. Since ionic bonds are generally stronger than metallic bonds, the deposition rate of the poisoning mode is relatively lower than that of the metal mode. Choosing the right mode may affect the quality of the final deposited coating as well as the flow and efficiency of the entire process.

[0019] The inventors have developed a new method of making improved protective coatings, and an apparatus for making these coatings in a cost-effective, high-volume manner. In the disclosed embodiments, transparent panels to be coated are introduced into a vacuum processing chamber through one or a series of loading stations, which enables the processing chamber to be maintained in a constant vacuum while receiving and transferring panels from an atmospheric environment. The processing chamber has a series of reactive sputtering deposition sources for sequentially building up an optical thin film stack. The substrate passes in front of each processing source along a continuous line, thereby successively depositing each layer of the thin film stack. At each given time, the first layer is deposited on the substrate n x On the substrate n, the last layer is deposited y On which substrate n y On the substrate x Several cycles were previously introduced into the processing chamber.

[0020] Unlike the prior art, which uses multiple vacuum chambers, one for each layer, here the sources for each layer are located in one vacuum chamber, with no valves to provide vacuum isolation between them. In fact, the reaction process for each source is controlled, so the composition for each layer is independently controlled and no cross contamination occurs. That is, if layer n i It is SiON with very low N content, and the layer n j If the N content is higher and the O content is lower, the gas flowing into each source in the source line is controlled to achieve the desired composition change without unwanted cross-flow of gas species.

[0021] In the disclosed embodiments, the system can be a linear system where the panels enter the vacuum at one end and exit at the other end, where each layer has an independent processing source. Conversely, the system can be configured as an elliptical path where the panels enter and exit the system from the same side, but preferably using independent loading stations. Once in the vacuum environment, the substrate moves in a straight line past the sources, but the process in each source is independently controlled based on the layer to be deposited. In some embodiments, the elliptical system allows the same stack to be created by making multiple passes around the ellipse, with the process changing with each pass. This implementation is more like a batch process where all substrates are coated with the same material at any given time. Then in the next step, the deposition material can be changed and all substrates receive the new layer at the same time.

[0022] As will be disclosed in more detail below, the thin film stack contains various compositions of SiOx and SiAlOxNy. The thin film stack is reactively sputtered from silicon (Si) and silicon aluminum (SiAl) targets. In the disclosed embodiments, all targets contain 3% to 15% aluminum. The aluminum in the target has multiple functions: it helps control the hardness stress, refractive index / refractive index of the target, and the manufacturing of the target. Without aluminum in the target, the manufacturing cost will be greatly increased.

[0023] By controlling the different mixtures deposited on the faceplate, the refractive index can be specifically tailored. The refractive index range for SiON can be controlled from about 1.46 for SiOx to about 2.0 for Si3N4. The refractive index range for AlON can be controlled from about 1.68 for Al2O3 to about 2 for AlN. The refractive index range for SiAlOxNy can be controlled from about 1.48 for SiAlOx to about 2.0 for SiAlNx. The nitrogen flow required to achieve higher refractive indices is relatively low, so process control is easier to achieve in a single processing chamber.

[0024] In the disclosed embodiment, the panel is coated with four layers: an adhesion layer, a stress grading layer, a protective layer, and an anti-reflection layer. After the substrate is optionally plasma cleaned, the adhesion layer is formed on the surface of the substrate. A stress grading interlayer is then formed on the adhesion layer. A protective layer is then formed on the stress grading interlayer. Finally, an anti-reflection layer is formed on the protective layer. With this arrangement, the adhesion layer and the stress grading layer enhance the integrity of the coating and extend its life, the protective layer enhances the scratch and wear resistance of the panel, and the anti-reflection layer enhances the optical performance of the panel.

[0025] In disclosed embodiments, the adhesion layer comprises an oxide-containing layer having a refractive index n less than 1.65. The adhesion layer does not contain nitrogen, and in some embodiments, the refractive index is set to be less than 1.5. The stress grading interlayer is composed of an oxide-containing layer having a refractive index n lower than that of the protective layer. The protective layer has a thickness at least three times that of the stress grading interlayer, and the refractive index of the protective layer is higher than the refractive index of the stress grading interlayer. The antireflective layer comprises a plurality of sublayers, wherein at least one sublayer has a higher refractive index than the protective layer, and at least one sublayer has a lower refractive index than the protective layer.

[0026] Figure 1A cross section of a protective coating is schematically depicted, showing the layers according to an embodiment. In this embodiment, the coating is applied to a transparent panel substrate 105 made of glass. An adhesion layer 110 is formed above the surface of the substrate. The adhesion layer is made of SiOx and can be sputtered in a poisoning mode or a metal mode. The refractive index n of the adhesion layer is set to be less than 1.65 or even less than 1.50. For example, the refractive index of the adhesion layer is 1.48. In the disclosed embodiment, the refractive index of the adhesion layer is not more than 0.005 higher than the refractive index of the substrate, and the refractive index of the adhesion layer is not more than 0.005 lower than the refractive index of the substrate. The thickness of the adhesion layer 110 is set to 40nm to 80nm, and the film stress of the adhesion layer is set to be less than 100mPa.

[0027] Next, a stress grading layer 115 is formed by sputtering two sub-layers 112 and 114 on the adhesion layer. The stress grading layer 115 grades stress through multiple sub-layers so that the interface energy or stress is not too high. The two sub-layers are made of SiAlOxNy films, but with different refractive indices. The first sub-layer is made of SiAlOxNy, where the oxygen flow and nitrogen flow are adjusted to control the relative OxNy composition to obtain the desired refractive index. The stress grading layer is designed to have a refractive index that is higher than that of the adhesion layer, but not as high as that of the protective layer, thereby acting as a "buffer" between the adhesion layer and the protective layer, thereby alleviating stress that may exist if the protective layer is formed directly on the adhesion layer.

[0028] exist Figure 1In the example shown, the refractive index n1 of the first sublayer 112 is higher than the refractive index n of the adhesion layer, here higher than 1.48, but the refractive index n1 of the first sublayer 112 is lower than the refractive index n2 of the second sublayer 114, and the refractive index n2 of the second sublayer 114 is still lower than the refractive index n3 of the protective layer, so n3>n2>n1>n. To achieve this result, for each subsequent layer, either or both of the ratio of nitrogen to oxygen or / and the ratio of aluminum to silicon are increased. In some embodiments, the refractive index of the stress grading layer 115 or sublayer 112 is substantially matched to the refractive index of the top surface of the optically transmissive substrate 105. In an alternative embodiment, the refractive index of the stress grading layer 115 or sublayer 112 is no more than 0.005 higher than the refractive index of the substrate and no more than 0.005 lower than the refractive index of the substrate. The first sublayer 112 is formed to a thickness of 40-200nm, and the second sublayer 114 is formed to a thickness of 50-200nm. In some embodiments, the total thickness of the stress grading layer 115 is at least 200 nm, while in other embodiments, the total thickness of the stress grading layer 115 is at least 1000 nm. In some embodiments, the film stress of the stress grading layer 115 is less than 100 mPa. In some embodiments, the stress grading layer 115 comprises a film having a film porosity of at least 10%. In some embodiments, the stress grading layer 115 comprises a material that is sputter deposited at a pressure of at least 10 mT and has a thermal conductivity value k<0.0001.

[0029] The protective layer 120 is formed over the stress grading layer 115 and is relatively thick, at least three times the thickness of the stress grading layer 115, here 2-4 microns. The protective layer 120 is made of SiAlOxNy, wherein the oxygen flow and nitrogen flow are adjusted to control the relative OxNy composition to obtain a refractive index n3 that is higher than the refractive index of all previous layers. The refractive index of the protective layer can be about 1.65 to about 1.80 or about 1.65 to about 1.70.

[0030] In another embodiment, if Figure 1 As shown by the dotted line in FIG. 8 , the protective layer is formed of two sub-layers, namely the first sub-layer 120 as described above and the second sub-layer 121 made of SiON.

[0031] The hardened anti-reflective coating 125 is formed above the protective coating and is made of several SiAlOxNy sublayers with alternating refractive indices. Specifically, the refractive index n4 of the first sublayer 122 formed directly on the protective layer is set to be higher than the refractive index of the protective layer 120, that is, n4>n3. The first sublayer is formed to have a thickness of 20-40nm. The refractive index n5 of the second sublayer 124 formed directly on the first sublayer 122 is lower than the refractive index of the first sublayer 122, that is, n4>n5>n3. The second sublayer 124 is formed to have a thickness of 20-40nm. The refractive index of the third sublayer 126 formed directly on the second sublayer 124 is the same as the refractive index of the first sublayer, that is, n4. The third sublayer 126 is formed to have a thickness of 40-80nm. The refractive index of the fourth sublayer 128, that is, the top layer of the stack, is the same as the refractive index of the first stress grading sublayer 112, that is, n1. In another embodiment, the fourth sublayer can be omitted, as shown by the dotted line. In addition, as shown by gradient 123, at least one sublayer of the antireflection layer 125 includes a dual-layer structure including a main layer (e.g., layer 124) and a thinner graded layer having a refractive index between the refractive index of the main layer (i.e., 124) and the refractive index of the abutting layer (here, 126). This arrangement can be applied to any sublayer of the antireflection coating.

[0032] The hard coating index and thickness can be modified for different substrates and applications. The optical structure index and thickness can be slightly different with the index of alternative glass-like materials. For example, changes can occur for substrates made of plastics, such as PMMA (polymethyl methacrylate), PET (polyethylene terephthalate), acrylic, etc. Sometimes, it is desirable to apply an inorganic anti-reflective coating to an organic transparent substrate. Inorganic coatings are more scratch-resistant than organic substrates, but inorganic coatings can be damaged when moisture from the organic substrate rises to the surface of the inorganic film and damages the material. Figure 2 An example of a protective film formed on an organic plastic substrate is shown.

[0033] exist Figure 2 In the embodiment of the present invention, the plastic substrate has a given refractive index n, which depends on the plastic material. In this embodiment, a barrier layer 220 is deposited on the surface of the substrate, and the refractive index n1 of the barrier layer is adjusted to match the refractive index of the plastic substrate, that is, n1=n. The barrier layer 220 is made of SiAlOxNy, but in order to achieve matching with the refractive index of the plastic (which is relatively low), the amount of Al and N is set to a relatively low level compared to the amount of Si and O. The barrier layer is formed to have a thickness of 2-4 microns.

[0034] A hardened anti-reflection layer 225 is then formed over the barrier layer 220, the hardened anti-reflection layer being made of several SiAlOxNy sublayers having alternating low / high refractive indices. Specifically, the first sublayer 222 formed directly on the barrier layer 220 is set to have a relatively high refractive index n2, which is about 1.90, and has a thickness of about 20-40nm. The refractive index n3 of the second sublayer 224 formed directly on the first sublayer 222 is lower than the refractive index of the first sublayer 222, i.e. n2>n3. The second sublayer 224 is formed to have a thickness of 20-40nm. The refractive index of the third sublayer 226 formed directly on the second sublayer 224 is the same as the refractive index of the first sublayer, i.e. n2. The third sublayer 226 is formed to have a thickness of 40-80nm. The fourth sublayer 228, i.e. the top layer of the stack, has a relatively low refractive index of about 1.49. The fourth sublayer 228 is formed to have a thickness of about 50-100nm.

[0035] All SiAlOxNy films are sputtered in "metallic mode" at constant voltage with feedback control of oxygen flow to achieve high rate and uniform refractive index film deposition. The hard coating refractive index and thickness can be modified for different substrates and applications. The optical structure index and thickness can be slightly different with the index of the alternative glass-like material. An Ar-O inductively coupled plasma (ICP) cleaning process can be applied to the glass substrate as required. Additionally, a plasma can be used prior to deposition of the adhesion layer, using high-energy bombardment of ions from the plasma to provide reduced interface energy at the interface between the surface of the substrate and the adhesion layer.

[0036] For plastic substrates, index matched SiAlOxNy low stress adhesion protection layer is sputtered in "metal mode". SiAlOxNy anti-reflective hard coating is sputtered in "metal mode" under constant voltage and oxygen flow control to achieve high rate uniform index film deposition. Optical structure index and thickness may vary slightly due to the index of alternative glass-like materials. N2 gas ICP adhesion / cleaning can be applied as needed.

[0037] The present invention provides a transparent panel, comprising: a transparent plate made of plastic; a barrier layer formed over the main surface of the transparent plate, the barrier layer made of a material including at least silicon and oxygen, and the refractive index of the barrier layer matches the refractive index of the transparent plate; an anti-reflection layer formed over the barrier layer, the refractive index of which is made of a plurality of sub-layers made of SiAlOxNy, wherein each sub-layer has a different x / y ratio, so that the sub-layers with the x / y ratio resulting in a high refractive index are interlaced with the sub-layers with the x / y ratio resulting in a lower refractive index. The barrier layer may include SiAlOxNy, wherein the amount of Al and N is adjusted to match the refractive index of the barrier layer with the refractive index of the transparent plate. The refractive index of the barrier layer may be less than 1.60 and may have a thickness of 2-4 microns. The refractive index of the top sub-layer of the anti-reflection layer may be less than 1.50, and the refractive index of the first sub-layer of the anti-reflection layer in contact with the barrier layer may be at least 1.90. Each sub-layer of the anti-reflection layer may have a thickness of 100nm or less.

[0038] Figure 3 A top view of one embodiment of a system 300 for forming a protective optical coating disclosed herein is schematically illustrated. Figure 3 The embodiment shown in shows a linear processing architecture, where substrates enter the system through a loading station (here LL1) at one end of the system and leave through a second loading station (here LL2) at the other end of the system. Each loading station has a gate valve (GV1-GV4) at its entrance and a gate valve at its exit, and has its own vacuum pumping and exhaust facilities (P1 and P2).

[0039] The system is formed by a single vacuum chamber 305 in which a plurality of sputtering stations 310 are arranged without partitions and / or gate valves between the stations. The vacuum chamber 305 has its own vacuum pumping and exhaust facilities P3. The number of sputtering stations 310 may vary depending on the number of layers to be deposited, as indicated by the ellipses. Figure 3 As shown, each sputtering station 310 has two cathodes 315, each of which is equipped with an elongated SiAl target. A gas injection manifold 320 is located between the two cathodes 315 in each station. In operation, a controller 330 monitors the gas flow, forming a closed loop so that the amount of gas supplied is consumed by the deposition process of the station and does not flow to adjacent stations. In this way, each processing station can deposit a film with a different SiAlOxNy composition, so that each film has a different refractive index. A significant advantage of this arrangement is that there is no need to open and close gate valves between stations as in the prior art, which greatly increases manufacturing time.

[0040] according to Figure 3The arrangement of N2 and O2 gases is introduced to each specific cathode pair in different ratios depending on the desired composition. The deposited film consumes most of the reactants (N and O), so the deposited film provides a substantial gas flow restriction, greatly reducing the reactants escaping from a specific cathode pair. The cathode pair further acts as a "restriction" because the upstream cathode consumes excess N:O, and the downstream also consumes excess N:O, and the resulting film composition is a mixture of small amounts of upstream / downstream gas plus gas introduced directly between the cathode pair. The composition is mainly determined by the gas introduced directly.

[0041] for Figure 3 In an embodiment, a sputtering system is provided, including a vacuum chamber 305, the vacuum chamber having a plurality of sputtering stations 310, the vacuum chamber having an unimpeded free fluid flow between the sputtering stations, as shown, without any gate valves between the stations 310. Each sputtering station has two sputtering sources 315, the targets of the two sputtering sources are made of the same material, and each sputtering station 310 has a gas injection manifold 320 located between the two sputtering sources 315. A gas delivery manifold 335 delivers a first gas (e.g., O2) and a second gas (e.g., N2) to each gas injection manifold 320. A controller 430 independently controls the ratio of the first gas and the second gas delivered to each gas injection manifold 320. A feedback loop measures the gas flow in each gas injection manifold and sends a corresponding signal to the controller, as shown by a double-headed arrow. A loading station (e.g., LL1) is mounted on the vacuum chamber, and a gate valve (e.g., GV) is sealingly attached between the vacuum chamber 305 and the loading station.

[0042] Figure 4 Another embodiment of the system 400 is shown, which uses a racetrack-type architecture so that each substrate can pass through a given processing station multiple times. In this alternative system configuration, the system can be configured to operate in a batch processing mode. The processing chamber is loaded with a substrate, and the substrate moves around an elliptical track until the desired number of layers are formed. The substrate is then exchanged with a new substrate. Gas isolation / confinement occurs in exactly the same way as a linear system; however, in a batch processing system, each time through the system, the layer formed in that pass may have a different composition mix. For example, in a first step, all modules 410 are operated with the same nitrogen flow / oxygen flow ratio, as controlled by the controller 430, so that the same type of layer is formed on all substrates at the same time. The nitrogen flow / oxygen flow ratio is then changed to a new ratio for all modules, and a second layer is formed on all substrates at the same time. In this way, the entire stack can be manufactured on multiple substrates at the same time, and when the entire stack is completed, all substrates exit the system via loading station LL2, and new substrates enter the system via loading station LL1.

[0043] like Figure 3As in the linear arrangement of the sputtering station 410, SiAl cathodes 415 are arranged in pairs in each sputtering station 410. Each pair of cathodes deposits y and x different SiAlOyNx, where y and x are determined by the ratio of gas O:N flow through the injection manifold 420. Each gas distribution manifold 420 is located between a pair of cathodes 415 to limit the gas flow to be consumed at the sputtering station and not flow to adjacent stations.

[0044] The present invention provides a sputtering system, comprising: a vacuum chamber, in which a plurality of sputtering stations are arranged, with unimpeded free fluid flow between the sputtering stations, each sputtering station having two sputtering sources, the targets of the two sputtering sources being made of the same material, and each sputtering station having a gas injection manifold located between the two sputtering sources; a gas delivery manifold, which delivers a first gas and a second gas to each gas injection manifold; a controller, which independently controls the ratio of the first gas and the second gas delivered to each gas injection manifold; a feedback loop, which measures the gas flow in each gas injection manifold and sends a corresponding signal to the controller; a loading station mounted on the vacuum chamber; and a gate valve sealingly attached between the vacuum chamber and the loading station.

[0045] In addition, the disclosed embodiments also provide a method for manufacturing a protective coating, comprising the following steps: introducing a transparent substrate into a vacuum environment; exposing the substrate to a plasma so that ion species bombard the top surface of the substrate; forming an adhesion layer by sputtering a silicon target; forming a stress grading layer on the adhesion layer by sputtering a SiAl target while injecting a mixture of oxygen and nitrogen into the sputtering plasma; forming a protective layer above the stress grading layer by sputtering the SiAl target while injecting a second mixture of oxygen and nitrogen into the sputtering plasma; and forming an anti-reflection layer above the protective layer by sputtering the SiAl target while injecting a third mixture of oxygen and nitrogen into the sputtering plasma. Figure 3 and Figure 4 As shown in the embodiment of FIG. 1 , depending on the chamber architecture, the SiAl target can be different or the same target for each layer. Thus, depending on the architecture used, a mixture of oxygen and nitrogen can be injected into the same or different sputtering targets for different layers.

[0046] It should be understood that the processes and techniques described herein are not inherently related to any particular device and can be implemented by any suitable combination of components. In addition, various types of general-purpose equipment can be used according to the teachings described herein. The present invention has been described in conjunction with specific examples, which are intended to be illustrative and not restrictive in all respects. Those skilled in the art will appreciate that many different combinations can be used. Suitable for practicing the present invention.

[0047] In addition, other embodiments of the present invention will be apparent to those skilled in the art from the description and practice of the invention disclosed herein. The various aspects and / or components of the embodiments may be used alone or in any combination. The description and examples should be considered as exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

Claims

1. A sputtering system for sputtering a transparent coating on a substrate, comprising: a vacuum chamber having a plurality of sputtering stations in the vacuum chamber with unimpeded free fluid flow between the sputtering stations, each sputtering station having two sputtering sources, the targets of the two sputtering sources being made of the same material, and each sputtering station having a gas injection manifold located between the two sputtering sources; a gas delivery manifold that delivers a first gas and a second gas to each of the gas injection manifolds; a controller that independently controls the ratio of the first gas and the second gas delivered to each gas injection manifold; a feedback loop that measures the gas flow into each gas injection manifold and sends a corresponding signal to the controller; as well as a loading station mounted on the vacuum chamber; and A gate valve is sealingly attached between the vacuum chamber and the loading station.

2. The sputtering system according to claim 1, wherein: The vacuum chamber is linear, and a loading station is mounted on one side of the vacuum chamber and a second loading station is mounted on an opposite side of the vacuum chamber.

3. The sputtering system according to claim 1, wherein: The vacuum chamber is U-shaped, and a loading station is mounted on one side of the vacuum chamber, and a second loading station is mounted on the same side of the vacuum chamber.

4. A method for producing a transparent protective coating, comprising the following steps: introducing a transparent substrate into a vacuum environment; forming an adhesion layer by sputtering a silicon target while injecting oxygen into a sputtering plasma; forming a stress grading layer on the adhesion layer by sputtering the SiAl target assembly while injecting a mixture of oxygen and nitrogen into the sputtering plasma; forming a protective layer over the stress grading layer by sputtering the SiAl target assembly while injecting a second mixture of oxygen and nitrogen into the sputtering plasma; as well as forming an antireflection layer over the protective layer by sputtering the SiAl target assembly while injecting a third mixture of oxygen and nitrogen into the sputtering plasma; The mixture of oxygen and nitrogen, the second mixture of oxygen and nitrogen, and the third mixture of oxygen and nitrogen all have different ratios of oxygen flow to nitrogen flow.

5. The method according to claim 4, wherein: Prior to the step of the second mixture of oxygen and nitrogen, the substrate is exposed to an argon or oxygen plasma to cause ion species to bombard the top surface of the substrate.

6. The method according to claim 4, wherein: The step of sputtering the SiAl target assembly while injecting a mixture of oxygen and nitrogen into the sputtering plasma includes passing the substrate beside two SiAl targets and injecting the mixture between the two targets.

7. The method according to claim 4, wherein: The step of forming the adhesion layer includes adjusting the implantation of oxygen to provide the adhesion layer with a refractive index less than 1.

50.

8. The method according to claim 7, wherein: The step of forming the stress grading layer includes adjusting the flow rates of oxygen and nitrogen so that the refractive index of the stress grading layer is higher than the refractive index of the adhesion layer but lower than the refractive index of the protection layer.

9. The method according to claim 8, wherein: The step of forming a stress grading layer includes forming a plurality of grading sub-layers, a first grading sub-layer being formed directly on the adhesion layer; The step of forming an anti-reflection layer includes forming a plurality of anti-reflection sub-layers, the first anti-reflection sub-layer is formed directly on the protective layer, and the top anti-reflection layer is the last layer of the transparent protective coating; and Therein, the top anti-reflection sublayer has the same refractive index as the first graded sublayer.

10. The method according to claim 4, wherein: The formation of the adhesion layer further includes an energy bombardment step.

11. A method, wherein: The energy bombardment step provides a reduced surface energy of the substrate.

12. A protective film for an optically transmissive substrate, comprising: an adhesion layer formed on a surface of the substrate; a stress grading interlayer formed over the adhesion layer; a protective layer formed over the stress grading interlayer; as well as an anti-reflection layer formed on the protective layer; in: The adhesion layer includes an oxide-containing layer having a refractive index n less than 1.65; The stress grading interlayer is composed of an oxide-containing layer, and the refractive index n of the stress grading interlayer is lower than the refractive index of the protective layer; The protective layer has a thickness at least three times greater than the thickness of the stress grading interlayer, and a refractive index of the protective layer is higher than a refractive index of the stress grading interlayer; The anti-reflection layer includes a plurality of sub-layers, wherein a refractive index of at least one sub-layer is higher than a refractive index of the protective layer, and a refractive index of at least one sub-layer is lower than a refractive index of the protective layer.

13. The protective film according to claim 12, wherein: The adhesion layer includes silicon and oxide.

14. The protective film according to claim 13, wherein: The adhesion layer also contains aluminum.

15. The protective film according to claim 14, wherein: The protective layer includes AlSiON.

16. The protective film according to claim 15, wherein The refractive index of the protective layer is about 1.65 to 1.

70.

17. The protective film according to claim 12, wherein: The protection layer comprises two sub-layers, a first sub-layer comprising AlSiON and a second sub-layer comprising SiON.

18. The protective film according to claim 12, wherein: The refractive index of the sub-layer abutting against the protective layer is higher than the refractive index of the protective layer.

19. The protective film according to claim 12, wherein: The anti-reflection layer includes three sublayers, wherein the first sublayer against the protective layer has a higher refractive index than the protective layer, the second sublayer against the first sublayer has a higher refractive index than the first sublayer, and the third sublayer against the second sublayer has a lower refractive index than the protective layer.

20. The protective film according to claim 12, wherein The anti-reflection layer includes four sublayers, the first sublayer against the protective layer has a higher refractive index than the protective layer, the second sublayer against the first sublayer has a higher refractive index than the protective layer but lower than the first sublayer, the third sublayer against the second sublayer has a higher refractive index than the second sublayer, and the fourth sublayer against the third sublayer has a lower refractive index than the protective layer.

21. The protective film according to claim 12, wherein: At least one sublayer in the antireflection layer comprises a double layer structure including a main layer and a thinner graded layer, the thinner graded layer having a refractive index between the main layer and the abutting layer.

22. The protective film according to claim 12, wherein: The transmittance through the protective film and the substrate is higher than the transmittance through the substrate without the film.

23. The protective film according to claim 12, wherein: The adhesion layer has a refractive index that substantially matches a refractive index of a top surface of the optically transmissive substrate.

24. The protective film according to claim 23, wherein: The refractive index of the adhesion layer is not more than 0.005 higher than the refractive index of the substrate and not more than 0.005 lower than the refractive index of the substrate.

25. The protective film according to claim 12, wherein: The film stress of the adhesion layer is less than 100 mPa.

26. The protective film according to claim 12, wherein: The stress grading layer has a refractive index substantially matched to a refractive index of a top surface of the optically transmissive substrate.

27. The protective film according to claim 26, wherein: The stress grading layer has a refractive index no greater than 0.005 higher than a refractive index of the substrate and no greater than 0.005 lower than a refractive index of the substrate.

28. The protective film according to claim 12, wherein: The film stress of the stress grading layer is less than 100 mPa.

29. The protective film according to claim 12, wherein: The stress grading layer includes a film having a film porosity of at least 10%.

30. The protective film according to claim 12, wherein: The stress grading layer includes AlSiON.

31. The protective film according to claim 12, wherein: The stress grading layer comprises a material sputter deposited at a pressure of at least 10 mT and having a thermal conductivity value k<0.0001.

32. The protective film according to claim 12, wherein: The stress grading layer comprises a thickness of at least 200 nm.

33. The protective film according to claim 12, wherein: The stress grading layer comprises a thickness of at least 1000 nm.

34. The protective film according to claim 12, wherein: The substrate includes a reduced interface energy with the adhesion layer provided by energy bombardment prior to deposition of the adhesion layer.

35. The protective film according to claim 34, wherein: The reduced interface energy provided by energy bombardment prior to adhesion layer deposition includes ICP using a carrier gas including N2.

36. The protective film according to claim 12, wherein: The adhesion layer does not contain nitrogen and the refractive index of the adhesion layer is less than 1.

5.

37. A transparent panel comprising: A transparent plate made of plastic; a barrier layer formed over a major surface of the transparent plate, the barrier layer being made of a material containing at least silicon and oxygen and having a refractive index matching that of the transparent plate; An anti-reflective layer is formed over the barrier layer, the refractive index of the anti-reflective layer being comprised of a plurality of sub-layers made of SiAlOxNy, wherein each sub-layer has a different x / y ratio such that sub-layers having x / y ratios producing a high refractive index are interleaved with sub-layers having x / y ratios producing a lower refractive index.

38. The transparent panel according to claim 37, wherein: The barrier layer includes SiAlOxNy, wherein the amounts of Al and N are adjusted to match the refractive index of the barrier layer with that of the transparent plate.

39. The transparent panel according to claim 38, wherein: The barrier layer has a refractive index of less than 1.

60.

40. The transparent panel according to claim 37, wherein: The thickness of the barrier layer is 2-4 microns.

41. The transparent panel according to claim 37, wherein: The top sublayer of the antireflection layer has a refractive index of less than 1.

50.

42. The transparent panel according to claim 37, wherein: The first sublayer of the antireflection layer in contact with the barrier layer has a refractive index of at least 1.

90.

43. The transparent panel according to claim 37, wherein: The thickness of each sub-layer of the antireflection layer is 100 nm or less.

44. A method for manufacturing a sputtering system, comprising: forming a vacuum chamber; A plurality of sputtering stations are formed inside the vacuum chamber without any fluid flow obstruction between the sputtering stations; Two sputtering sources with the same target material are installed in each sputtering station; installing a gas injection manifold between the two sputtering sources in each sputtering station; Install airflow feedback loops to indicate airflow in each manifold.

45. The method of claim 44, wherein: The sputtering stations are arranged in a row, and the method further includes installing a loading chamber at one end of the vacuum chamber and installing a second loading chamber at an opposite end of the vacuum chamber.

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