Hydrophilic sputtered ar coating

Abstract

To provide an ophthalmic article having a coating system which provides anti-reflective and easy-to-clean properties to the ophthalmic article.SOLUTION: A coating system 20 disclosed herein includes alternating layers of a low-refractive-index metal oxide and high-refractive-index metal oxynitrides and corresponding high-refractive-index metal oxides. The coating system 20 provides favorable surface energy to the ophthalmic article when at least one layer of the high-refractive-index metal oxynitride is encapsulated between two layers of low-refractive-index metal oxide.SELECTED DRAWING: Figure 1

Description

Related Applications

[0001] This application claims priority to U.S. Provisional Application No. 62 / 873,779, entitled "HYDROPHILIC-LIKE SPUTTERED AR COATING," filed on Jul. 12, 2019, the entire contents of which are incorporated herein by reference.

Technical Field

[0002] The present invention relates to optical coatings, and more particularly to hydrophilic sputter coatings that are easy to clean and anti-reflective.

Background Art

[0003] One or more functional coatings can be applied to the surface of an ophthalmic article to impart different properties or characteristics to that surface. Such properties or characteristics imparted by the coating can include color, gloss, reflectivity, abrasion resistance, optical transparency, water repellency, anti-fogging, anti-reflection, stain resistance, and ease of cleaning. Of these various properties, surface properties or ease of cleaning and anti-reflective characteristics have potentially broad applications in the ophthalmic industry.

[0004] Dirt, oil, and dust are major contaminants that form on ophthalmic lenses. Removal of these contaminants is ongoing and often difficult, depending on the wearer's environment, the type of ophthalmic lens coating, and the materials required to clean them.

[0005] To keep the surface of ophthalmic lenses clean, many manufacturers have adopted the use of hydrophobic coatings on these lenses, selling them as having a smoother or more hydrophobic surface than competing eyeglasses and thus being easier to clean. However, market research has revealed that these easily cleanable coating technologies using hydrophobic or slippery lens surfaces do not function at the expected level for several reasons.

[0006] The first reason is that a hydrophobic or slippery surface does not necessarily mean that oil and dirt will always fall off or be easily removed. Instead, oil and dirt tend to move around easily on the surface, and in the absence of friction from the surface, there is a tendency for dirt to adhere to the surface of the lens.

[0007] The second reason is that current easily cleanable coating technologies using hydrophobic surfaces are mainly aimed at achieving the highest possible contact angles for both water and oil. The reason for these high contact angles is due to the correlation between the high contact angles of water and oil and the surface resistance to dirt, fingerprints, and ease of cleaning. Generally, a water contact angle greater than 110° before friction and greater than 105° after friction is commonly used. However, oil mixed with dirt tends to move or smear across the slippery lens surface, so a high contact angle does not necessarily indicate that the surface is easy to clean.

[0008] The third reason is that the hydrophobic surface performance may not be maintained over a long period of time. Hydrophobic coatings deteriorate or wear over time during lens cleaning. When this occurs, oil and dirt accumulate on the lens, making it difficult to remove without using soap or a similar cleaning solution.

[0009] Typically, these hydrophilic coatings rely on the photocatalytic activity of the coating, and the most common of this property is the coating of titania or titanium dioxide (TiO2). As a wide-band semiconductor, TiO2 absorbs light in the ultraviolet (UV) wavelength range. Through the absorption process, electron-hole pairs are generated, and the photo-generated holes are responsible for the hydrophilicity (water contact angle less than 10°) of the coating surface. When contaminants such as water or oil are trapped in the pores, charged species, such as hydroxyl ions and hydroxyl radicals, are formed by oxidation. These charged species can have several effects: a) they can impart hydrophilicity on the surface (when TiO2 increases the concentration of hydroxyl radicals on the surface, through surface reorganization); b) they can provide a self-cleaning mechanism through the oxidation of surface contaminants; and c) they have a catalytic effect for converting contaminants into non-hazardous substances.

[0010] The photocatalysis of TiO2 coatings is the subject of many patents, including U.S. Patent Application Publication No. 2003 / 0048538, U.S. Patent No. 7527867, U.S. Patent No. 5854708, and U.S. Patent No. 6830785, the contents of which are incorporated herein by reference. These patents use the photocatalytic properties of TiO2 to increase hydrophilicity (water contact angle less than 10°) and, in some cases, provide a self-cleaning mechanism that helps maintain hydrophilicity when the surface is soiled.

[0011] In some cases, silicon dioxide (SiO2) is added as a dopant into the photocatalytic TiO2 as seen in U.S. Patent No. 6830785, or added as an upper layer of TiO2 as seen in U.S. Patent Application Publication No. 2003 / 0048538, the contents of which are incorporated herein by reference for reference, to enhance the hydrophilic behavior of the TiO2 coating. Titanium oxynitride (TiO x N y) The use of x N y is also discussed in a publication by Asahi ["Visible Light Photo catalyst in Nitrogen Doped Titanium Oxides", Asahi, Morikawa, Ohwaki, Aoki, Taga, Science page 293, 269], the content of which is incorporated herein by reference. By adding nitrogen, the band gap of the semiconductor is narrowed so that the absorption of high-energy visible light can generate electron-hole pairs. TiO x N y (using either UV or visible illumination) The photocatalytic effect observed is considerably weaker than that of TiO2 under UV illumination. In other words, TiO x N y is not as efficient as TiO2 in converting photons into a desirable change in surface energy or reactivity.

[0012] However, these types of hydrophilic coatings typically do not have long-term durability and cannot be used in applications where abrasion exists. Furthermore, with these types of hydrophilic coatings, the surface energy of the ophthalmic lens surface decreases over time and eventually approaches zero, and thus the hydrophilic coating no longer provides a desirable surface energy for facilitating the easy cleaning characteristics of the ophthalmic lens.

[0013] Therefore, there is a need to develop coatings and coating systems that overcome the drawbacks of conventional hydrophilic coatings by providing both improved cleaning characteristics and improved durability over a longer period of time.

Summary of the Invention

[0014] The present invention provides a coating and a coating system that impart effective easy-to-clean characteristics to the surface of ophthalmic articles. According to some embodiments, the coating system for an ophthalmic article is achieved by providing a substrate having a surface and a plurality of alternating layers of a low refractive index layer and a high refractive index layer including a metal oxide containing silicon dioxide. The alternately arranged high refractive index layers include a second metal oxide containing titanium dioxide or zirconium dioxide and at least one metal oxynitride containing titanium oxynitride or zirconium oxynitride, all of which are deposited on the surface of the substrate. In this coating configuration, when the ophthalmic article has at least one high refractive index titanium oxynitride or zirconium oxynitride encapsulated between two layers of silicon dioxide having a low refractive index, it has a surface free energy in the range of about 50 - 70 mN / m for a long period, for example, approximately 40 days.

[0015] According to some embodiments of the present invention, the high refractive index metal oxynitride (titanium or zirconium) is designed for an anti-reflection optical laminate modified to have a hydrophilic type surface for enhancing its cleanability or to function as an optical article. The layer is preferably configured within an anti-reflection (AR) optical laminate so that no other layer is required outside the AR laminate to facilitate cleaning of the optical article. The metal oxynitride films are used in combination and generate hydrophilicity based on the ratio of nitrogen to oxygen during sputtering of thin film AR when encapsulated between silicon dioxides.

[0016] In some embodiments of the present invention, a method for manufacturing an ophthalmic article having easy-to-clean and anti-reflection characteristics is described. The method includes providing a substrate having a first surface and having a plurality of alternating layers of a low refractive index metal oxide and a high refractive index metal oxide and metal oxynitride formed on the first surface. The plurality of alternating layers further include at least one high refractive index metal oxynitride encapsulated between two layers of the low refractive index metal oxide. Through the encapsulation of at least one high refractive index layer of the metal oxynitride between two layers of the low refractive index metal oxide, easy-to-clean characteristics are imparted to the ophthalmic article. The surface cleanability ratio of the ophthalmic article in this coating system is preferably greater than 90%.

Brief Description of the Drawings

[0017] These and other aspects, features, and advantages of the embodiments of the present invention will become apparent and be elucidated from the following description of the embodiments of the present invention with reference to the accompanying drawings.

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DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and will fully convey the scope of the present invention to those skilled in the art. The terms used in the detailed description of the embodiments shown in the accompanying drawings are not intended to limit the present invention. In the drawings, like numbers refer to like elements.

[0036] The present invention provides a coating system for ophthalmic articles including at least a coating layer of a high refractive index metal oxynitride. The presence of at least one layer of metal oxynitride in the anti-reflection optical laminate of an ophthalmic article provides a preferred surface energy for making the surface essentially hydrophilic, which enhances the easy-to-clean property of the surface of the ophthalmic article from dirt, skin oil, and dust. Ophthalmic articles to which the easy-to-clean coating or layer of the present invention can be applied include, but are not limited to, glass, plastic, metal, painted or colored surfaces, and other materials for which cleanability is desired.

[0037] In some embodiments of the present invention, the surface of an ophthalmic article having an easily cleanable coating or layer with an increased surface energy that persists for a long time is provided with at least a layer of high refractive index titanium oxynitride or zirconium oxynitride. In some embodiments, an easily cleanable anti-reflective optical laminate of an ophthalmic article includes at least one layer of titanium oxynitride or zirconium oxynitride together with a layer of silicon dioxide. In some other embodiments, an easily cleanable anti-reflective optical laminate of an ophthalmic article includes at least a layer of titanium oxynitride or zirconium oxynitride together with layers of silicon dioxide and titanium dioxide or zirconium dioxide.

[0038] In some embodiments of the present invention, a process for preparing an anti-reflective laminate having an easily cleanable property includes depositing at least one layer of high refractive index titanium oxynitride or zirconium oxynitride on a low refractive index layer of silicon dioxide using DC pulse sputtering at 150 Khz in a vacuum. In some embodiments, the surface of an easily cleanable anti-reflective optical laminate of an ophthalmic article generates a controlled hydrophilic surface energy when at least one layer of high refractive index titanium oxynitride or zirconium oxynitride is encapsulated between two layers of low refractive index silicon dioxide in the optical laminate.

[0039] According to some embodiments, a non-limiting example of a standard anti-reflective and easily cleanable laminate design uses a five-layer structure of an L / H / L / H / L laminate, where L is a low refractive index silicon dioxide layer and H is a high refractive index layer of titanium oxynitride, zirconium oxynitride, titanium dioxide or zirconium dioxide. In some embodiments, an ophthalmic article has a long lifespan and generates a controlled hydrophilic surface energy when at least the high refractive index layer includes a titanium oxynitride or zirconium oxynitride layer.

[0040] In some embodiments of the present invention, the preparation of the titanium oxynitride or zirconium oxynitride layer involves sputter deposition from a metal target of titanium or zirconium in the presence of oxygen and nitrogen to form the desired metal oxynitride layer. In some embodiments of the present invention, the preparation of the low refractive index material of silicon dioxide involves sputter deposition from a silicon target in the presence of oxygen to deposit silicon dioxide.

[0041] In some embodiments of the present invention, zirconium with a specification vivid 5 / 7 CX / CC (CC - concave, CX - convex) and a purity of 99.98% is used for sputtering as a high refractive index metal. In some embodiments, silicon with a purity of 99.999% is used for sputtering as a low refractive index material. In some other embodiments, for all controlled tests, silicon is doped with 6% boron as a low refractive index material.

[0042] In some embodiments of the present invention, the sputtered gas contains argon, oxygen, and nitrogen in any given process flow. According to some embodiments, the mass flow controller used during the process is 50 sccm for both the argon flow and the oxygen flow. When using nitrogen as the sputter gas, a lower flow rate of 3.5 sccm is required to coat the nitride, so a mass flow controller of 5 sccm is used instead of 50 sccm. In some embodiments of the present invention, the adhesion layer of the silicon process is about 20 - 30 angstroms thick during the test.

[0043] In some embodiments, a method of making metal oxynitrides is carried out by using a reactive plasma barrel and DC pulse magnetron sputtering with a metal mode. The sputtering system used in the present invention is detailed in U.S. Patent Application Publication No. 2014 / 074912, the content of which is incorporated herein by reference. In the sputtering process, the material is applied as a very thin metal and rotated through a reactive plasma. Depending on the configuration of the plasma source and the placement of the cathode, most of the gas species can be delivered into the cathode or the plasma barrel. In some embodiments, an inert gas, such as argon, and a reactive gas, such as nitrogen, are delivered to the cathode, and another reactive gas, such as oxygen, is delivered to the plasma barrel. In some embodiments, a mass flow controller of 2.5 - 3.5 sccm is sufficient to obtain a metal oxynitride layer in a consistent process. In the present invention, all samples are prepared using a Mycoat DC pulse sputtering system with a metal mode plasma barrel for reacting the metal film to an oxide or oxynitride.

[0044] In the present invention, the anti - reflective color specifications are used in tests where they are tracked from zero time to a certain period. Further, in the present invention, a hydrophilic anti - reflective process is used with many different lens types. Non - limiting examples of such lenses are Polycarbonate Tegra and Clearblue filter, CR39, each having a high refractive index of 1.67 and 1.70, respectively. The original anti - reflective recipe is modified for color and spectrum adjustment as needed, due to specifications that have little effect on the surface energy and cleanliness results.

[0045] In some embodiments of the present invention, the high refractive index layer of titanium oxynitride or zirconium oxynitride affects the antireflective laminate of the ophthalmic article from three perspectives. The first perspective is the change in the surface morphology during the growth of the thin film layer of titanium oxynitride or zirconium oxynitride in the laminate. In some embodiments, a thin film layer of titanium oxynitride or zirconium oxynitride with a thickness of 10 nm functions in the same way as a thin film layer of titanium oxynitride or zirconium oxynitride with a thickness of 100 nm in terms of surface energy and / or surface morphology. In some embodiments, the arrangement of the thin film layer of titanium oxynitride or zirconium oxynitride in the antireflective optical laminate changes how the overall optical laminate behaves with respect to cleanliness and surface free energy. According to some embodiments, a non-limiting example of a standard antireflective and easy-to-clean laminate design employs a five-layer structure of an L / H / L / H / L laminate. Here, L is a low refractive index silicon dioxide layer, and H is a high refractive index layer with at least a titanium oxynitride or zirconium oxynitride coating. In this regard, a high refractive index means a refractive index greater than about 1.7 at a reference wavelength, for example, a wavelength of about 550 nanometers. A low refractive index means a refractive index less than about 1.5 at a reference wavelength, for example, a wavelength of about 550 nanometers. This type of columnar growth of the L / H / L / H / L laminate also increases the surface area, and the increase in surface area plays a role in achieving a controlled surface free energy (SFE), which ultimately leads to an increase in the easy-to-clean characteristics of the ophthalmic article. Also, the columnar growth can result in an increase in the coefficient of friction on the surface, leading to a "grabby feel" on the lens surface.

[0046] A second aspect in which the presence of a single layer or multiple layers of metal (Ti / Zr) oxynitride affects the antireflection laminate is by providing a controlled surface free energy for the overall antireflection laminate. In some embodiments, the presence of a single layer or multiple layers of metal (Ti / Zr) oxynitride affects the antireflection laminate by providing a controlled surface energy in the range of about 50 to 70 mn / m. In such embodiments where the controlled surface energy is in the range of about 50 to 70 mn / m, each layer of the single layer or multiple layers of metal (Ti / Zr) oxynitride interacts with the other optical laminate layers and contributes to the overall surface free energy of the hydrophilic surface and the overall cleanliness of the surface.

[0047] A third aspect in which the presence of a single layer or multiple layers of metal (Ti / Zr) oxynitride affects the hydrophilicity of the surface is due to the suspected photocatalytic properties of the titanium or zirconium oxynitride layer by generating holes in the presence of sunlight (photons), thereby oxidizing surface water and oil by these holes to generate OH radicals.

[0048] Referring now to FIG. 1 of the present invention, this figure shows an embodiment in which the surface of an article 10 (e.g., an optical lens) is provided with a durable anti-reflection coating having easy-to-clean properties. According to this embodiment of FIG. 1, the coating system 20 includes a five-layer laminate of alternating L / H / L / H / L layers, where L is a low refractive index silicon dioxide layer (20a, 20c, 20e) and H is a high refractive index layer (20b or 20d), at least one of which is composed of titanium oxynitride or zirconium oxynitride (20b or 20d). The other high refractive index layer may be a titanium dioxide, zirconium dioxide, titanium oxynitride, or zirconium oxynitride layer. The pre-adjusted easy-to-clean anti-reflection laminate 20 can use, for example, at least three layers in which the high refractive index layer and the low refractive index layer are alternately arranged, but the number of alternately arranged layers does not necessarily have to be limited (e.g., the laminate 20 can include 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or more layers). In this regard, the laminate can have layers 20n equal to the number of layers in which n is present.

[0049] For example, the refractive layer 20n may include an alternating layer of low refractive index silicon dioxide and high refractive index titanium oxynitride. In another example, the refractive layer 20n can include an alternating layer of low refractive index silicon dioxide, 1) one or more layers of high refractive index titanium oxynitride, and 2) one or more layers of high refractive index titanium dioxide. In another example, the refractive layer 20n may include an alternating layer of low refractive index silicon dioxide and high refractive index zirconium oxynitride. In another example, the refractive layer 20n can include an alternating layer of low refractive index silicon dioxide, 1) one or more layers of high refractive index zirconium oxynitride, and 2) one or more layers of high refractive index zirconium dioxide. In all embodiments of the present invention, the antireflection optical laminate of the ophthalmic article that is easy to clean includes at least a layer of high refractive index titanium oxynitride or zirconium oxynitride together with a layer of low refractive index silicon dioxide and a layer of high refractive index titanium dioxide or zirconium dioxide. In some embodiments, at least one layer of high refractive index titanium oxynitride or zirconium oxynitride (FIG. 1, 20b or 20d) is encapsulated between two layers of low refractive index silicon dioxide (20a, 20c, 20e) in the laminate.

[0050] FIG. 2 shows an alternative example of an embodiment of the present invention in which the coating system 20 includes a seven-layer laminate of alternating L / H / L / H / L / L / H / L layers, where L is a low refractive index silicon dioxide layer (20a, 20c, 20e, 20g), H is a high refractive index layer, and at least one of the high refractive index layers is a titanium oxynitride or zirconium oxynitride (20b or 20d or 20f) coating / layer. The other high refractive index layers may be titanium dioxide or zirconium dioxide layers. The pre-adjusted antireflection laminate 20 that is easy to clean can use, for example, at least three layers in which the high refractive index layer and the low refractive index layer are alternately arranged, but the number of alternately arranged layers does not necessarily have to be limited (for example, the laminate 20 can include 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or more layers). In this regard, the laminate can have a layer 20n equal to the number of layers in which n exists.

[0051] Next, referring to the table in Figure 3, this table compares the differences in refractive index, thickness, and surface roughness between the high refractive index layers of zirconium oxynitride and zirconium oxide. To measure this data, an ellipsometer is used. Thin films of zirconium oxynitride and zirconium dioxide are coated on fused silica and measured. The silica is normalized from the measured values. The data shows little difference in the refractive index difference (e.g., a difference of 0.0032) and the optical composition of the materials between the zirconium oxynitride and zirconium dioxide layers, but the third column of the table shows a difference in surface roughness (e.g., a difference of about 0.63 nm) between zirconium oxynitride and zirconium dioxide. The high refractive index coating of zirconium oxynitride has a surface roughness of 4.43 nm, which is higher than the surface roughness of 3.80 nm of the high refractive index zirconium dioxide coating. Since increased surface roughness usually correlates with a more hydrophilic surface, the high refractive index coating of zirconium oxynitride with a higher surface roughness of 4.43 nm tends to be essentially more hydrophilic compared to the high refractive index coating of zirconium dioxide with a surface roughness of 3.80 nm.

[0052] Figure 4 shows a graphical representation of both the measured contact angles (of water and iodomethane) and the calculated surface free energies (total, dispersive, and polar components) for a layer of silicon dioxide, a layer of silicon dioxide having zirconium oxynitride, and a layer of zirconium oxynitride encapsulated between layers of silicon dioxide. Note that the date of August 1, 2018 (8 / 1 / 18) is the sample preparation date (0-hour measurement). In Figure 4, antireflective, easily cleanable laminates are assembled from single layers of high and low refractive index materials of different thicknesses, and the contact angles (of water and iodomethane) and total surface free energies (total, dispersive, and polar components) are measured with a goniometer. The experiments show that the changes in contact angle and total surface free energy depend on the layers and the sequence of arrangement of the individual layers. Here, the total surface free energy is composed of a dispersive component and a polar energy component. The atoms and molecules that cause the surface energy / tension of a substance can be explained by different types of interactions between the atoms and molecules on the surface. For example, the interactions caused by temporary fluctuations in the charge distribution in an atom / molecule are called dispersive interactions (e.g., van der Waals interactions) and contribute to the total surface free energy as the dispersive free energy. However, polar interactions include Coulomb interactions between permanent dipoles and between permanent dipoles and induced dipoles (e.g., hydrogen bonds) and contribute to the total surface free energy as the polar free energy. Thus, the surface energy / tension of a component is additively composed of the dispersivity and polar energy of the surface. Figure 5 shows a graphical representation of both the measured contact angles (of water and iodomethane) and the calculated surface free energies (total, dispersive, and polar components) for the surface of silicon dioxide, a layer of silicon dioxide having zirconium oxynitride, and a layer of zirconium oxynitride encapsulated between layers of silicon dioxide. Note that the date of September 27, 2018 (9 / 27 / 18) is the measurement date 58 days after the sample preparation date of August 1, 2018 (8 / 1 / 18) shown in Figure 4. Figure 5 shows that the measured contact angles of water and iodomethane for a zirconium oxynitride layer grown on a single silicon dioxide layer are larger than those for a zirconium oxynitride layer encapsulated between layers of silicon dioxide.On the one hand, the calculated surface free energy and polar free energy of the zirconium oxynitride layer encapsulated between silicon dioxide layers are higher 58 days after the start of the experiment than when a single layer of zirconium oxynitride grows on the silicon dioxide monolayer (i.e., not encapsulated). From Figure 5, it should be noted that the dispersive free energy does not change much over time between the zirconium oxynitride encapsulated between silicon dioxide layers and the layer where a single layer of zirconium oxynitride grows on the silicon dioxide monolayer (i.e., not encapsulated). Encapsulating a high refractive index zirconium oxynitride layer between low refractive index silicon dioxide layers has an important influence on the polar component of the surface free energy shown in a later part of the present invention.

[0053] Figures 6 and 7 of the present invention show a comparison of the measured contact angles of deionized water over time between the high refractive index layers of titanium dioxide and titanium oxynitride (Figure 6) and the high refractive index layers of zirconium dioxide and zirconium oxynitride (Figure 7). In this comparative experiment, a normal sharp 5 / 7 layer laminate having alternating high refractive index layers of zirconium dioxide and low refractive index layers of silicon dioxide is used as a baseline. Figure 6 shows that the contact angle of deionized water measured for the laminate of titanium dioxide layers is much larger than the contact angle of deionized water measured for the laminate of titanium oxynitride layers 10 days, 20 days, and more than 35 days after the start of the experiment. Similarly, Figure 7 shows that the contact angle of deionized water measured for the laminate of zirconium dioxide layers is much larger than the contact angle of deionized water measured for the laminate of zirconium oxynitride layers 5 days and 10 days after the start of the experiment.

[0054] Referring to FIGS. 8 and 9 of the present invention, these figures show the comparison of the measured contact angles of diiodomethane over time between the high refractive index layers of titanium dioxide and titanium oxynitride (FIG. 8) and the high refractive index layers of zirconium dioxide and zirconium oxynitride (FIG. 9). In this comparative experiment, a normal sharp 5 / 7 layer laminate having a high refractive index layer of zirconium dioxide and a low refractive index layer of silicon dioxide is used as a baseline. FIG. 8 shows that the contact angle of diiodomethane measured for the laminate of the titanium dioxide layer is much larger than the contact angle of diiodomethane measured for the laminate of the titanium oxynitride layer 10 days, 20 days, and 30 days after the start of the experiment. Similarly, FIG. 9 shows that the contact angle of diiodomethane measured for the laminate of the zirconium dioxide layer is much larger than the contact angle of diiodomethane measured for the laminate of the zirconium oxynitride layer 5 days and 10 days after the start of the experiment.

[0055] Next, the measured contact angle values shown in FIGS. 6 to 9 are used to determine the total surface free energy (SFE) of the surface and the dispersive and polar component surface energies of the surface in the experiments shown in FIGS. 10 to 15 below.

[0056] FIGS. 10 and 11 of the present invention show a comparative experiment of the measured total surface free energy (SFE) over time between a laminate including a high refractive index layer of titanium dioxide and titanium oxynitride (FIG. 10) and a laminate including a high refractive index layer of zirconium dioxide and zirconium oxynitride (FIG. 11). FIG. 10 shows that the total surface free energy (SFE) measured for the laminate of the titanium oxynitride layer is much higher than the total surface free energy (SFE) measured for the laminate of the titanium dioxide layer 5 days, 10 days, 20 days, and almost 40 days after the start of the experiment. Similarly, FIG. 11 shows that the total surface free energy (SFE) measured for the laminate of the zirconium oxynitride layer is much higher than the total surface free energy (SFE) measured for the laminate of the titanium dioxide layer 5 days and 10 days after the start of the experiment. In some embodiments, the total surface energy obtained for the metal (Ti / Zr) oxynitride-based antireflection structure is about 50 to 70 mN / m.

[0057] Figures 12 and 13 of the present invention show a comparative experiment of the measured dispersive component surface energy over time between a laminate including a high refractive index layer of titanium dioxide and titanium oxynitride (Figure 12) and a laminate including a high refractive index layer of zirconium dioxide and zirconium oxynitride (Figure 13). Figure 12 shows that the measured dispersive component surface energy between the titanium dioxide layer and the titanium oxynitride layer becomes equal at about 40 mN / m approximately 40 days after the start of the experiment. Similarly, Figure 13 shows that the measured dispersive component surface energy between the zirconium dioxide layer and the zirconium oxynitride layer is not much distinguishable between 5 days and 10 days after the start of the experiment. These experiments shown in Figures 12 and 13 indicate that the dispersive component of the surface energy has little influence or variation over time between laminates composed of layers of titanium dioxide and titanium oxynitride or laminates composed of layers of zirconium dioxide and zirconium oxynitride. From this experiment, it can be concluded that the dispersive interaction between atoms and molecules (for example, van der Waals interaction) caused by temporary fluctuations in the charge distribution is obtained from at least titanium and zirconium in metals, but is not limited thereto, and there is little difference between layers of metal oxides and metal oxynitrides.

[0058] Figures 14 and 15 of the present invention show a comparative experiment of the measured polar component surface energy over time between the high refractive index layers of titanium dioxide and titanium oxynitride (Figure 14) and the high refractive index layers of zirconium dioxide and zirconium oxynitride (Figure 15). Figure 14 shows that the measured polar component surface energy of titanium oxynitride is much higher than that of titanium dioxide measured 5 days, 10 days, 20 days, and approximately 40 days after the start of the experiment. Similarly, Figure 15 shows that the measured polar component surface energy of zirconium oxynitride is much higher than that of zirconium dioxide measured 5 days and 10 days after the start of the experiment. From this experiment, it can be concluded that the polar interactions (e.g., hydrogen bonds) between permanent dipoles and between permanent dipoles and induced dipoles are much higher in the layer of zirconium oxynitride than in the layer of zirconium dioxide.

[0059] The graphs of Figures 14 and 15 show that for coatings using only high refractive index metal (Ti / Zr) oxides, the polar energy decreases as it approaches zero, and as a result, the hydrophilic properties tend to decrease. In contrast, metal (Ti / Zr) oxynitrides show an initial decrease in polar surface energy and then stabilize at a much higher non-zero value, which helps to maintain more stable hydrophilic properties. In some embodiments, the polar energy of metal (Ti / Zr) oxynitrides is about 15 - 40 mN / m. According to some embodiments of the present invention, the stability of the polar component energy of metal (Ti / Zr) oxynitrides may depend on the optimal amount of nitrogen used in the preparation of the metal (Ti / Zr) oxynitride thin film. If more than this amount of nitrogen is used in the sputtering process, the hydrophilic properties of the metal (Ti / Zr) oxynitride film may not be stable, and it may not be possible to obtain a controlled total surface energy of the metal (Ti / Zr) oxynitride film in the range of about 50 - 70 mN / m.

[0060] It should be noted that the mere presence of the SiO2 layer in the optical laminate imparts hydrophilic properties to the antireflective optical laminate for a short period, and then this hydrophilic property decreases over time. The descriptions of FIGS. 6 to 15 above show that the presence of the high refractive index metal oxynitride surface coating embedded between the SiO2 layers creates persistence in the hydrophilic behavior of the antireflective optical laminate. When the high refractive index metal oxynitride is encapsulated between the SiO2 layers, the combined layers act synergistically. In all of the antireflective optical laminates of FIGS. 6 to 15, the top layer always remains SiO2. The surface energy data from FIGS. 10 to 15 shows that the use of the oxynitride coating results in an increase in the surface energy of the entire antireflective optical laminate.

[0061] Referring now to FIG. 16 of the present invention, this figure shows a cleanliness test used to determine the ease of removing oily residues from the lens surface. At the start of this experiment, synthetic skin oil (sebum) is applied using a tampon rubber stamper. The use of the tamp stamper is necessary to apply a controlled amount of sebum that gives a predictable amount of optical haze. The sebum temperature is controlled at 60° C. A lens with a base curve of either 4 or 6 diopters is used. Limiting the curve range improves the repeatability of the test. Next, after rotating the lens 120 degrees, the optical haze of the sample is measured three times. The average of these measurements is the reported initial haze. The sample is placed on a friction test system with a weight of 2.2 kg on a soft foam pad using a polyester cloth whose weave crosses the sample at an angle of 90 degrees to the stroke. After 6 strokes, the cloth is replaced and the haze is measured. After 18 strokes, a fine haze measurement is taken. In some embodiments of the present invention, sebum stamping should be at a transmittance of ~35% using a haze guard. This is because some surfaces have some different textures. Heating and imprinting pressure of the sebum helps with the uniformity and reproducibility of the haze start point. As described above, the sample is rotated ~120 degrees at each haze measurement and the average value is taken. In hydrophobic sampling, the haze measurement value can get worse due to sebum contamination. This is one of the main drawbacks of hydrophobic coatings where, due to the low surface energy, oil and dirt tend to move around on the surface.

[0062] The cleanliness ratio can be calculated by subtracting the fine haze reading value after 18 strokes from the initial stamp haze reading value, dividing the result by the initial stamp haze reading value, and multiplying by 100, based on the haze reading values after the initial stamping and after 18 strokes with the polyester cloth. This is represented here by the formula "cleanliness ratio" = (initial reading - final reading) / initial reading × 100.

[0063] The above formula is used to compare the "cleanability ratio" of different materials, lenses from different manufacturers, and manufacturing processes. FIG. 16 shows a comparison of the "cleanability ratio" between zirconium oxynitride and zirconium dioxide used as the high refractive index layer of the antireflection structure. FIG. 16 further shows that the initial haze reading value of the laminate of the antireflection structure prepared using zirconium dioxide as the high refractive index layer is 33.88, and the initial haze reading value of the laminate of the antireflection structure prepared using zirconium oxynitride as the high refractive index layer is 37.88. After 18 strokes with a polyester cloth, the haze reading value of the laminate of the antireflection structure prepared using zirconium dioxide as the high refractive index layer is 23.58, and the haze reading value of the laminate of the antireflection structure prepared using zirconium oxynitride as the high refractive index layer is 0.87. When the "cleanability ratio" was calculated using the above formula, it can be seen from FIG. 16 that the "cleanability ratio" of the laminate of the antireflection structure made using the high refractive index zirconium oxynitride layer is much higher (97.63) than the "cleanability ratio" of the laminate of the antireflection structure made using the high refractive index zirconium dioxide layer.

[0064] FIG. 17 shows a comparison of the cleanability ratio between a hydrophobic coating of a competing company, a coating that is easy to clean in U.S. Patent Application Publication No. 2015 / 0226886 (the content of which is incorporated herein by reference) which is a previous application of the applicant, and the coating (displayed as hydrophilic AR) disclosed in the present invention. From FIG. 17, the coating that is easy to clean in U.S. Patent Application Publication No. 2015 / 0226886 which is a previous application of the applicant and the coating that is easy to clean of the present invention (displayed as hydrophilic AR) provide surfaces that are more effectively cleaned by wiping than the industrial standard hydrophobic coatings shown in Comparative Examples 1-6 of FIG. 17. For example, the cleanability ratio of the industrial standard hydrophobic coatings shown in Comparative Examples 1-6 is in the range of 17% - 70%. On the other hand, the cleanability ratios of the applicant's U.S. Patent Application Publication No. 2015 / 0226886 and the present invention are 92% and 95% respectively. Therefore, the lenses according to the present invention exhibit better cleanability than the currently commercially available and tested "easy-to-clean" lenses.

[0065] Although the invention has been described with respect to specific embodiments and uses, those skilled in the art will be able to generate additional embodiments and modifications in light of this teaching without departing from the spirit of the claimed invention or exceeding its scope. Accordingly, it should be understood that the drawings and description herein are provided by way of example to facilitate understanding of the invention and should not be construed as limiting its scope.

Claims

1. An ophthalmic article having ease of cleaning and antireflection properties, comprising: a substrate having a surface; and a laminate on the surface, wherein the laminate includes a low refractive index layer containing a metal oxide and a plurality of high refractive index layers alternately including 1) at least one metal oxynitride layer or 2) at least one metal oxynitride layer and at least one metal oxide layer. An ophthalmic article characterized by this.

2. When the at least one high refractive index metal oxynitride layer is encapsulated between two layers of the low refractive index metal oxide, the ophthalmic article has a surface free energy in the range of about 50 to 70 mN / m over a long period of time. The ophthalmic article according to Claim 1.

3. The ophthalmic article according to Claim 1, wherein the low refractive index metal oxide contains silicon dioxide.

4. The ophthalmic article according to Claim 1, wherein the high refractive index metal oxide contains titanium dioxide or zirconium dioxide.

5. The ophthalmic article according to Claim 1, wherein the at least one high refractive index metal oxynitride contains titanium oxynitride or zirconium oxynitride.

6. When the at least one high refractive index metal oxynitride is encapsulated between two layers of the low refractive index metal oxide, the ophthalmic article contains a polar surface energy in the range of about 15 to 40 mN / m over a long period of time. The ophthalmic article according to Claim 1.

7. The ophthalmic article according to Claim 6, wherein the at least one high refractive index metal oxynitride contains zirconium oxynitride encapsulated between two layers of low refractive index silicon dioxide.

8. The ophthalmic article according to Claim 6, wherein the at least one high refractive index metal oxynitride contains titanium oxynitride encapsulated between two layers of low refractive index silicon dioxide.

9. When the at least one high refractive index metal oxynitride is encapsulated between two layers of the low refractive index metal oxide, the surface cleanliness ratio of the ophthalmic article exceeds 90%. The ophthalmic article according to Claim 1.

10. When the at least one high refractive index metal oxynitride containing zirconium oxynitride is encapsulated between two layers of the low refractive index metal oxide containing silicon dioxide, the surface cleanliness ratio of the ophthalmic article is 97.63%. The ophthalmic article according to Claim 9.

11. An optical laminate for imparting ease of cleaning and antireflection properties to a surface, An optical laminate characterized by including at least one high refractive index layer of metal oxynitride encapsulated between two low refractive index layers of metal oxide.

12. The optical laminate according to claim 11, wherein the high refractive index layer of the metal oxynitride contains titanium oxynitride or zirconium oxynitride.

13. The optical laminate according to claim 11, wherein the low refractive index layer of the metal oxide contains silicon dioxide.

14. The optical laminate according to claim 11, wherein the high refractive index layer of the metal oxide corresponding to the metal oxynitride contains titanium dioxide or zirconium dioxide.

15. The surface free energy of the optical laminate including the high refractive index layer of the metal oxynitride encapsulated between the two low refractive index layers of the metal oxide remains in the range of about 50 to 70 mN / m for about 40 days, according to claim 11.

16. The optical laminate according to claim 11, wherein when the at least one high refractive index metal oxynitride is encapsulated between the two low refractive index layers of the metal oxide, the optical laminate includes a polar surface energy in the range of about 15 to 40 mN / m for about 40 days.

17. The optical laminate according to claim 11, wherein the high refractive index layer of the metal oxynitride and the high refractive index layer of the metal oxide corresponding to the metal oxynitride have substantially the same refractive index.

18. The optical laminate according to claim 11, wherein the high refractive index layer of the metal oxynitride has a higher surface roughness than the surface roughness of the high refractive index layer of the metal oxide corresponding to the metal oxynitride.

19. A method for manufacturing an ophthalmic article having easy cleanability and anti-reflection properties, comprising: providing a substrate having a surface; forming a laminate on the surface, wherein the laminate includes a plurality of alternating low refractive index layers containing metal oxide and high refractive index layers including 1) at least one metal oxynitride layer, or 2) at least one metal oxynitride layer and at least one metal oxide layer; A method for manufacturing an ophthalmic article, characterized in that the surface cleanability ratio of the ophthalmic article exceeds 90%.

20. The manufacturing method according to claim 19, further comprising the step of imparting the easy cleanability to the ophthalmic article by encapsulating the at least one high refractive index layer of metal oxynitride between two layers of low refractive index metal oxide.

21. The method according to claim 19, wherein the step of forming the plurality of alternating layers of the low refractive index metal oxide and the high refractive index metal oxide and the at least one layer of the high refractive index metal oxynitride on the surface comprises coating the surface with an alternating layer of low refractive index silicon dioxide, high refractive index titanium dioxide or zirconium dioxide, and high refractive index titanium oxynitride or zirconium oxynitride.

22. The method according to claim 20, wherein the step of imparting the easy-to-clean property to the ophthalmic article by enclosing the at least one high refractive index layer of metal oxynitride between two layers of the low refractive index metal oxide comprises enclosing the high refractive index layer of titanium oxynitride or zirconium oxynitride between two layers of low refractive index silicon dioxide.

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