Ophthalmic article, optical laminate, and method for manufacturing ophthalmic article

Abstract

An ophthalmic article having a coating system that provides anti-reflective and easy-to-clean properties to the ophthalmic article. The coating system includes alternating layers of a low refractive index metal oxide, a high refractive index metal oxynitride, and a corresponding high refractive index metal oxide. The coating system provides a 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 the low refractive index metal oxide.

Description

Related Applications

[0001] This application claims priority to U.S. Provisional Application No. 62 / 873,779, entitled "HYDROPHILIC-LIKE SPUTTERED AR COATING," filed July 12, 2019, which is incorporated herein by reference in its entirety. [Technical Field]

[0002] The present invention relates to optical coatings, and more particularly to easy-to-clean, anti-reflective, hydrophilic sputtered coatings. [Background technology]

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

[0004] Dirt, oil, and dust are the primary contaminants that form on ophthalmic lenses. Depending on the wearer's environment, the type of ophthalmic lens coating, and the materials needed to clean them, removing these contaminants can be continuous and often difficult.

[0005] To keep the surfaces of ophthalmic lenses clean, many manufacturers have adopted the use of hydrophobic coatings on these lenses, marketing the hydrophobic coatings as providing a slippery or hydrophobic surface than competing eyeglasses and therefore easier to clean. However, market research has revealed that these easy-to-clean coating technologies that use hydrophobic or slippery lens surfaces do not perform as well as expected 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 easy to remove. Instead, oil and dirt tend to move around on the surface and, in the absence of friction from the surface, the dirt tends to stick to the surface of the lens.

[0007] The second reason is that current easy-to-clean coating technologies using hydrophobic surfaces are primarily directed 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 high water and oil contact angles and surface resistance to dirt, fingerprints, and ease of cleaning. In general, water contact angles greater than 110° before rubbing and greater than 105° after rubbing are commonly used. However, a high contact angle does not necessarily indicate an easy-to-clean surface, as oil mixed with dirt tends to migrate or smear across the slippery lens surface.

[0008] The third reason is that the hydrophobic surface performance may not be maintained over time. The hydrophobic coating may deteriorate or wear away over time while cleaning the lenses. When this happens, oil and dirt can accumulate on the lenses and become difficult to remove without using soap or similar cleaning solutions.

[0009] These hydrophilic coatings typically rely on the photocatalytic activity of the coating, the most common of which are titania or titanium dioxide (TiO2) coatings. As a broadband semiconductor, TiO2 absorbs light in the ultraviolet (UV) wavelengths. The absorption process generates electron-hole pairs, and the photogenerated holes are responsible for the hydrophilic nature of the coating surface (water contact angle less than 10°). When contaminants such as water or oil are trapped in the pores, they are oxidized to form charged species, such as hydroxyl ions and hydroxyl radicals. These charged species can have several effects: a) they can impart hydrophilicity to the surface (by surface reorganization, when TiO2 increases the concentration of hydroxyl radicals on the surface); b) they can provide a self-cleaning mechanism through the oxidation of surface contaminants; and c) they can have a catalytic effect for converting contaminants to non-hazardous substances.

[0010] The photocatalytic activity of TiO2 coatings is the subject of numerous patents, including U.S. Patent Application Publication No. 2003 / 0048538, U.S. Patent No. 7,527,867, U.S. Patent No. 5,854,708, and U.S. Patent No. 6,830,785, 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 surfaces become soiled.

[0011] In some cases, silicon dioxide (SiO2) is added as a dopant to the photocatalytic TiO2, as in U.S. Pat. No. 6,830,785, or as a top layer of TiO2, as in U.S. Patent Application Publication No. 2003 / 0048538, the contents of which are incorporated herein by reference, to enhance the hydrophilic behavior of the TiO2 coating. x N yThe use of TiO is also discussed in a publication by Asahi ["Visible Light Photocatalyst in Nitrogen Doped Titanium Oxides," Asahi, Morikawa, Ohwaki, Aoki, Taga, Science 293, pp. 269], the contents of which are incorporated herein by reference. The addition of nitrogen narrows the band gap of the semiconductor so that absorption of high-energy visible light can generate electron-hole pairs. x N y The existence of photocatalytic behavior with TiO is similar to that of TiO when exposed to UV irradiation. x N y The photocatalytic effect observed under UV or visible illumination is significantly weaker than that of TiO under UV illumination. x N y is not as efficient as TiO2 in converting photons into desired changes 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 wear is present. Furthermore, these types of hydrophilic coatings cause the surface energy of the ophthalmic lens surface to decrease over time, eventually approaching zero, and therefore the hydrophilic coating no longer provides a favorable surface energy to promote easy cleaning characteristics of the ophthalmic lens.

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

[0014] The present invention provides coatings and coating systems that impart effective easy-cleaning properties to the surface of an ophthalmic article. According to some embodiments, the coating system for an ophthalmic article is achieved by providing a substrate having a surface and multiple alternating low and high refractive index layers comprising a metal oxide, including silicon dioxide. The alternating high refractive index layers comprise a second metal oxide, including titanium dioxide or zirconium dioxide, and at least one metal oxynitride, including titanium oxynitride or zirconium oxynitride, all deposited on the surface of the substrate. In this coating configuration, the ophthalmic article comprises a surface free energy in the range of about 50-70 mN / m for an extended period of time, e.g., approximately 40 days, when the at least one high refractive index titanium oxynitride or zirconium oxynitride is encapsulated between two layers of low refractive index silicon dioxide.

[0015] According to some embodiments of the present invention, high refractive index metal oxynitrides (titanium or zirconium) are designed into modified anti-reflective optical stacks to function as hydrophilic-type surfaces or optical articles to enhance their cleanability. The layers are preferably configured within the anti-reflective (AR) optical stack, so that no other layers are needed outside the AR stack to facilitate cleaning of the optical article. When used in combination and encapsulated between silicon dioxide, the metal oxynitride films generate hydrophilic properties based on the ratio of nitrogen to oxygen during sputtering of the thin-film AR.

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

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

[0018] [Figure 1] FIG. 1 is a perspective view of a coated substrate according to one embodiment of the present invention.

[0019] [Figure 2] FIG. 2 is a perspective view of a coated substrate according to another embodiment of the present invention.

[0020] [Figure 3] Figure 3 shows the differences in refractive index, thickness, and surface roughness between zirconium oxide and zirconium oxynitride.

[0021] [Figure 4] FIG. 4 is a graph showing a combined plot of measured contact angles (for water and diiodomethane) and calculated surface energies (total, dispersive, and polar components) on a surface freshly coated with a layer of silicon dioxide, a surface freshly coated with layers of silicon dioxide and zirconium oxynitride, and a surface freshly coated with zirconium oxynitride encapsulated between two silicon dioxide layers.

[0022] [Figure 5] FIG. 5 is a graph showing a combined plot of measured contact angles (for water and diiodomethane) and calculated surface energies (total, dispersive, and polar components) for surfaces coated with the layers described in FIG. 4 after 58 days of testing.

[0023] [Figure 6]Figure 6 is a comparative graph showing the contact angle of water over time on a surface coated with an AR coating containing SiO2 and either titanium oxide or titanium oxynitride. The top layer in the stack configuration is SiO2.

[0024] [Figure 7] Figure 7 is a comparative graph showing the contact angle of water over time on a surface coated with an AR stack containing SiO2 and either zirconium oxide or zirconium oxynitride. The top layer of the stack is SiO2.

[0025] [Figure 8] Figure 8 is a comparative graph showing the contact angle over time of diiodomethane on a surface coated with an AR coating containing SiO2 and either titanium oxide or titanium oxynitride. The top layer of the stack is SiO2.

[0026] [Figure 9] Figure 9 is a comparative graph showing the contact angle over time of diiodomethane on a surface coated with an AR coating using SiO2 and either zirconium oxide or zirconium oxynitride. The top layer of the stack is SiO2.

[0027] [Figure 10] Figure 10 is a comparative graph showing the surface free energy over time of a surface coated with an AR coating containing SiO2 and either titanium dioxide or titanium oxynitride. The top layer of the stack is SiO2.

[0028] [Figure 11] Figure 11 is a comparative graph showing the surface free energy over time of a surface coated with an AR coating containing SiO2 and either zirconium oxide or zirconium oxynitride. The top layer of the stack is SiO2.

[0029] [Figure 12] Figure 12 is a comparative graph showing the free energy of the dispersion component of a surface over time when coated with an AR coating containing SiO2 and either titanium dioxide or titanium oxynitride. The top layer of the stack is SiO2.

[0030] [Figure 13] Figure 13 is a comparative graph showing the free energy of the dispersion component of a surface over time when coated with an AR coating containing SiO2 and either zirconium oxide or zirconium oxynitride. The top layer of the stack is SiO2.

[0031] [Figure 14] Figure 14 is a comparative graph showing the free energy of the polar components of the surface over time when coated with SiO2 and either titanium dioxide or titanium oxynitride. The top layer of the stack is SiO2.

[0032] [Figure 15] Figure 15 is a comparative graph showing the free energy of the polar components of the surface over time when coated with SiO2 and either zirconium oxide or zirconium oxynitride. The top layer of the stack is SiO2.

[0033] [Figure 16] Figure 16 is a comparative graph showing the cleanability ratios between zirconium oxide or zirconium oxynitride used as the high refractive index layer in an anti-reflective, easy-to-clean laminate. The top layer of the laminate is SiO2.

[0034] [Figure 17]FIG. 17 is a table showing a comparison of cleanability ratios between a competitor's hydrophobic coating, the easy-to-clean coating in the previous U.S. Pat. No. 10,613,255, and the coating disclosed in this invention (labeled "hydrophilic AR"). DETAILED DESCRIPTION OF THE INVENTION

[0035] Specific embodiments of the present invention will now 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 set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments shown in the accompanying drawings is not intended to be limiting of the present invention. In the drawings, like numbers refer to like elements.

[0036] The present invention provides a coating system for an ophthalmic article comprising at least a coating layer of a high refractive index metal oxynitride. The presence of at least one metal oxynitride layer in the antireflective optical stack of the ophthalmic article provides a favorable surface energy to make the surface essentially hydrophilic, which enhances the easy-to-clean properties of the surface of the ophthalmic article from dirt, skin oils, 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 stained surfaces, and other materials where cleanability is desired.

[0037] In some embodiments of the present invention, the easy-to-clean coating or layer comprises at least a layer of high refractive index titanium or zirconium oxynitride, which provides the surface of the ophthalmic article with long-lasting increased surface energy. In some embodiments, the easy-to-clean antireflective optical stack of the ophthalmic article comprises at least one layer of titanium or zirconium oxynitride together with a layer of silicon dioxide. In some other embodiments, the easy-to-clean antireflective optical stack of the ophthalmic article comprises at least a layer of titanium 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 antireflective stack with easy-to-clean properties comprises depositing at least one layer of high refractive index titanium or zirconium oxynitride onto a low refractive index layer of silicon dioxide using 150 Khz DC pulse sputtering in a vacuum. In some embodiments, the surface of the easy-to-clean antireflective optical stack of an ophthalmic article generates a controlled hydrophilic surface energy when at least one layer of high refractive index titanium or zirconium oxynitride is encapsulated between two layers of low refractive index silicon dioxide within the optical stack.

[0039] According to some embodiments, a non-limiting example of a standard anti-reflective and easy-to-clean laminate design uses a five-layer structure of 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, ophthalmic articles produce long-lasting, controlled hydrophilic surface energy when at least the high refractive index layer comprises a titanium oxynitride or zirconium oxynitride layer.

[0040] In some embodiments of the present invention, the preparation of a titanium 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 a silicon dioxide low refractive index material 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 vivid 5 / 7 CX / CC (CC-concave, CX-convex) specifications and 99.98% purity is used as the high refractive index metal for sputtering. In some embodiments, silicon with 99.999% purity is used as the low refractive index material for sputtering. In other embodiments, for all controlled tests, silicon is doped with 6% boron as the low refractive index material.

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

[0043] In some embodiments, a method for fabricating metal oxynitrides is carried out using DC pulse magnetron sputtering with a metallic mode using a reactive plasma barrel. The sputtering system used in this invention is described in detail in U.S. Patent Application Publication No. 2014 / 074912, the contents of which are incorporated herein by reference. In the sputtering process, the material is applied as a very thin metal and then spun through a reactive plasma. Depending on the configuration of the plasma source and the placement of the cathode, the majority of the gas species can be delivered to the cathode or 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 to 3.5 sccm is sufficient to obtain a metal oxynitride layer in a consistent process. In this invention, all samples were prepared using a Mycoat DC pulse sputtering system with a metallic mode plasma barrel to react the metal film to the oxide or oxynitride.

[0044] In the present invention, anti-reflective color specifications are used in tests that track the color from time zero over a period of time. Furthermore, in the present invention, the hydrophilic anti-reflective process is used with many different lens types. Non-limiting examples of such lenses are Polycarbonate Tegra and clear blue filter, CR39, with high refractive indices of 1.67 and 1.70, respectively. The original anti-reflective recipe is modified as needed to adjust color and spectrum for specifications that have little effect on surface energy and cleanliness results.

[0045] In some embodiments of the present invention, high refractive index titanium or zirconium oxynitride layers affect the antireflective stack of ophthalmic articles in three ways. The first aspect is the change in surface morphology during the growth of the titanium or zirconium oxynitride thin film layer in the stack. In some embodiments, a 10 nm thick titanium or zirconium oxynitride thin film layer performs similarly to a 100 nm thick titanium or zirconium oxynitride thin film layer in terms of surface energy and / or surface morphology. In some embodiments, the placement of the titanium or zirconium oxynitride thin film layer in the antireflective optical stack changes how the overall optical stack behaves with respect to cleanability and surface free energy. A non-limiting example of a standard antireflective and easy-to-clean stack design, according to some embodiments, employs a five-layer structure of L / H / L / H / L stack, where L is a low refractive index silicon dioxide layer and H is at least a high refractive index layer of the titanium or zirconium oxynitride coating. In this regard, a high refractive index refers to a refractive index greater than about 1.7 at a reference wavelength, e.g., about 550 nanometers. A low refractive index refers to a refractive index less than about 1.5 at a reference wavelength, e.g., about 550 nanometers. This type of columnar growth in L / H / L / H / L stacks also increases the surface area, which plays a role in achieving a controlled surface free energy (SFE), ultimately leading to increased ease-of-cleaning properties of the ophthalmic article. Columnar growth also increases the coefficient of friction on the surface, which can result in a "grabby feel" on the lens surface.

[0046] A second way in which the presence of a metal (Ti / Zr) oxynitride layer or layers affects the antireflection stack is by providing a controlled surface free energy for the total optical antireflection stack. In some embodiments, the presence of a metal (Ti / Zr) oxynitride layer or layers provides a controlled surface free energy for the total optical antireflection stack. N / m. The controlled surface energy is about 50-70 m / s. NIn such embodiments, in the range of / m, each layer or layers of metal (Ti / Zr) oxynitride interacts with the other optical stack layers and contributes to the overall surface free energy of the hydrophilic surface and the overall cleanliness of the surface.

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

[0048] Referring now to Figure 1 of the present invention, this figure illustrates an embodiment in which a surface of an article 10 (e.g., an optical lens) is provided with a durable anti-reflective coating having easy-cleaning properties. According to this embodiment of Figure 1, the coating system 20 includes a five-layer stack 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. Preconditioned easy-to-clean antireflection stack 20 can, for example, utilize at least three alternating high and low refractive index layers, but need not necessarily have a limited number of alternating layers (e.g., stack 20 can include 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or more layers). In this regard, stack can have layers 20n, where n is equal to the number of layers present.

[0049] For example, the refractive layer 20n can include alternating layers of low refractive index silicon dioxide and high refractive index titanium oxynitride. In another example, the refractive layer 20n can include alternating layers 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 can include alternating layers of low refractive index silicon dioxide and high refractive index zirconium oxynitride. In another example, the refractive layer 20n can include alternating layers 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 easy-to-clean antireflective optical stack of the ophthalmic article includes at least a layer of high refractive index titanium oxynitride or zirconium oxynitride along 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 a stack.

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

[0051] Referring now to the table in Figure 3, this table compares the differences in refractive index, thickness, and surface roughness between high-index layers of zirconium oxynitride and zirconium oxide. An ellipsometer is used to measure this data. Thin films of zirconium oxynitride and zirconium dioxide are coated on fused silica and measured. Silica is normalized from the measurements. While the data shows little difference in refractive index (e.g., a difference of 0.0032) and optical composition of the materials between the zirconium oxynitride and zirconium dioxide layers, the third column of the table shows a difference in surface roughness between the zirconium oxynitride and zirconium dioxide layers (e.g., a difference of approximately 0.63 nm). The high-index zirconium oxynitride coating has a surface roughness of 4.43 nm, which is higher than the 3.80 nm surface roughness of the high-index zirconium dioxide coating. Increased surface roughness typically correlates with a more hydrophilic surface, so a high refractive index coating of zirconium oxynitride with a higher surface roughness of 4.43 nm tends to be inherently more hydrophilic compared to a 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 (for water and diiodomethane) and calculated surface free energies (total, dispersive, and polar components) for a silicon dioxide layer, a silicon dioxide layer with zirconium oxynitride, and a layer of zirconium oxynitride encapsulated between silicon dioxide layers. Note that the date August 1, 2018 (8 / 1 / 18) is the sample preparation date (time 0). In Figure 4, antireflective, easy-to-clean laminates are assembled from single layers of high- and low-refractive-index materials of different thicknesses, and the contact angles (for water and diiodomethane) and total surface free energies (total, dispersive, and polar components) are measured with a goniometer. Experiments show that the changes in contact angle and total surface free energy depend on the layer and the arrangement order of the individual layers. Here, the total surface free energy is composed of dispersive and polar energy components. The atoms and molecules that cause the surface energy / tension of a material can be explained by different types of interactions between atoms and molecules on the surface. For example, interactions caused by transient fluctuations in charge distribution among atoms / molecules are called dispersive interactions (e.g., van der Waals interactions) and contribute to the total surface free energy as dispersive free energy. However, polar interactions, including Coulombic interactions between permanent dipoles and between permanent and induced dipoles (e.g., hydrogen bonds), also contribute to the total surface free energy as polar free energy. Thus, the surface energy / tension of a component is additively composed of the dispersive and polar energies of the surface. Figure 5 shows a graphical representation of both the measured contact angles (for water and diiodomethane) and the calculated surface free energies (total, dispersive, and polar components) of a silicon dioxide surface, a silicon dioxide layer with zirconium oxynitride, and a layer of zirconium oxynitride encapsulated between the silicon dioxide layers. Note that the date September 27, 2018 (9 / 27 / 18) is the measurement date 58 days after the specimen creation date of August 1, 2018 (8 / 1 / 18) shown in Figure 4. FIG. 5 shows that the measured water and diiodomethane contact angles of zirconium oxynitride layers grown on a single silicon dioxide layer are larger than those of zirconium oxynitride layers encapsulated between silicon dioxide layers.On the other hand, the calculated surface free energy and polar free energy of the zirconium oxynitride layer encapsulated between silicon dioxide layers is higher than that of the zirconium oxynitride monolayer grown on the silicon dioxide monolayer (i.e., unencapsulated) 58 days after the start of the experiment. It should be noted from Figure 5 that the dispersion free energy does not change significantly over time between the zirconium oxynitride encapsulated between silicon dioxide layers and the zirconium oxynitride monolayer grown on the silicon dioxide monolayer (i.e., unencapsulated). The encapsulation of a high-index zirconium oxynitride layer between low-index silicon dioxide layers has a significant effect on the polar component of the surface free energy shown later in this invention.

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

[0054] Referring to Figures 8 and 9 of the present invention, these figures show a comparison of the measured contact angles of diiodomethane over time between high-refractive index layers of titanium dioxide and titanium oxynitride (Figure 8) and high-refractive index layers of zirconium dioxide and zirconium oxynitride (Figure 9). In this comparative experiment, a standard clear 5 / 7-layer stack with a high-refractive index layer of zirconium dioxide and a low-refractive index layer of silicon dioxide is used as the baseline. Figure 8 shows that the contact angles of diiodomethane measured for the titanium dioxide stack are much larger than those measured for the titanium oxynitride stack 10, 20, and 30 days after the start of the experiment. Similarly, Figure 9 shows that the contact angles of diiodomethane measured for the zirconium dioxide stack are much larger than those measured for the zirconium oxynitride stack 5 and 10 days after the start of the experiment.

[0055] The contact angle measurements shown in Figures 6-9 are then 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 following experiments shown in Figures 10-15.

[0056] Figures 10 and 11 of the present invention show experimental comparisons of the measured total surface free energy (SFE) over time between a stack including high-refractive index layers of titanium dioxide and titanium oxynitride (Figure 10) and a stack including high-refractive index layers of zirconium dioxide and zirconium oxynitride (Figure 11). Figure 10 shows that the measured total surface free energy (SFE) for the stack of titanium oxynitride layers is much higher than the measured total surface free energy (SFE) for the stack of titanium dioxide layers 5, 10, 20, and nearly 40 days after the start of the experiment. Similarly, Figure 11 shows that the measured total surface free energy (SFE) for the stack of zirconium oxynitride layers is much higher than the measured total surface free energy (SFE) for the stack of titanium dioxide layers 5 and 10 days after the start of the experiment. In some embodiments, the resulting total surface energy of metal (Ti / Zr) oxynitride-based antireflective structures is about 50-70 mN / m.

[0057] Figures 12 and 13 of the present invention show comparative experiments of the measured dispersive component surface energy over time between a stack including high refractive index layers of titanium dioxide and titanium oxynitride (Figure 12) and a stack including high refractive index layers of zirconium dioxide and zirconium oxynitride (Figure 13). Figure 12 shows that the measured dispersive component surface energies between the titanium dioxide and titanium oxynitride layers are 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 energies between the zirconium dioxide and zirconium oxynitride layers are less distinct between 5 and 10 days after the start of the experiment. These experiments, shown in Figures 12 and 13, demonstrate that the dispersive component of surface energy has little effect or variation over time between stacks consisting of titanium dioxide and titanium oxynitride layers or zirconium dioxide and zirconium oxynitride layers. From this experiment, it can be concluded that the dispersive interactions between atoms and molecules (e.g., van der Waals interactions) caused by temporary fluctuations in charge distribution differ little between metal oxide and metal oxynitride layers, with metals being at least, but not limited to, titanium and zirconium.

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

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

[0060] It should be noted that the presence of only an SiO2 layer in the optical stack provides hydrophilic properties to the anti-reflection optical stack for a short period of time, and then this hydrophilic property diminishes over time. The discussion of Figures 6-15 above demonstrates that the presence of a high refractive index metal oxynitride surface coating embedded between SiO2 layers creates permanence for the hydrophilic behavior of the anti-reflection optical stack. When a high refractive index metal oxynitride is encapsulated between SiO2 layers, the combined layers act synergistically. In all of the anti-reflection optical stacks in Figures 6-15, the top layer always remains SiO2. The surface energy data from Figures 10-15 demonstrate that the use of an oxynitride coating results in an increase in the surface energy of the entire anti-reflection optical stack.

[0061] Referring now to Figure 16 of the present invention, this figure shows a cleanability test used to determine the ease of removing oily residue from the lens surface. At the beginning of this experiment, synthetic skin oil (sebum) is applied using a rubber stamper. The use of the stamper is necessary to apply a controlled amount of sebum, which imparts a predictable amount of optical haze. The sebum temperature is controlled at 60°C. Lenses with a base curve of either 4 or 6 diopters were used. Limiting the curve range improves the repeatability of the test. The optical haze of the sample was then measured three times after rotating the lens 120 degrees. The average of these measurements is the reported initial haze. The sample was placed in a friction test system with a 2.2 kg weight on a soft foam pad using polyester fabric with the weave crossing the sample at a 90-degree angle to the stroke. After six strokes, the fabric was replaced and the haze was measured. After 18 strokes, a fine haze measurement was taken. In some embodiments of the present invention, the sebum stamping should result in a transmission of ~35% using HazeGuard. This is because some surfaces have different textures. The application of heat and pressure to the sebum aids in uniformity and reproducibility of the haze onset. As mentioned above, the sample is rotated ~120 degrees for each haze measurement and the average value is taken. With hydrophobic sampling, haze measurements can be worst due to sebum contamination. This is one of the major drawbacks of hydrophobic coatings, where oil and dirt tend to move around on the surface due to their low surface energy.

[0062] From the haze readings after initial stamping and after 18 strokes on the polyester fabric, a cleanliness ratio can be calculated by subtracting the fine haze reading of 18 strokes from the initial stamp haze reading, dividing the result by the initial stamp haze reading, and multiplying by 100, represented herein by the formula "Cleanliness Ratio" = (initial reading - final reading) / initial reading x 100.

[0063] The above formula is used to compare the "cleanability ratio" of lenses made from different materials, manufacturers, and manufacturing processes. Figure 16 shows a comparison of the "cleanability ratio" between zirconium oxynitride and zirconium dioxide used as high-refractive index layers in anti-reflective structures. Figure 16 further shows that the initial haze reading for the anti-reflective structure laminate prepared using zirconium oxide as the high-refractive index layer was 33.88, while the initial haze reading for the anti-reflective structure laminate prepared using zirconium oxynitride as the high-refractive index layer was 37.88. After 18 strokes with a polyester cloth, the haze reading for the anti-reflective structure laminate prepared using zirconium oxide as the high-refractive index layer was 23.58, while the haze reading for the anti-reflective structure laminate prepared using zirconium oxynitride as the high-refractive index layer was 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 anti-reflection structure laminate made using a high refractive index zirconium oxynitride layer is much higher (97.63) than the "cleanability ratio" of the anti-reflection structure laminate made using a high refractive index zirconium dioxide layer.

[0064] FIG. 17 shows a comparison of the cleanability ratios between a competitor's hydrophobic coating, the easy-to-clean coating in applicant's prior application U.S. Patent Application Publication No. 2015 / 0226886 (the contents of which are incorporated herein by reference), and the coating disclosed in the present invention (labeled "Hydrophilic AR"). From FIG. 17, it can be seen that the easy-to-clean coating in applicant's prior application U.S. Patent Application Publication No. 2015 / 0226886 and the easy-to-clean coating of the present invention (labeled "Hydrophilic AR") provide surfaces that are more effectively cleaned by wiping than the industry-standard hydrophobic coatings shown in Comparative Examples 1-6 in FIG. 17. For example, the cleanability ratios of the industry-standard hydrophobic coatings shown in Comparative Examples 1-6 range from 17% to 70%. Meanwhile, the cleanability ratios of applicant's U.S. Patent Application Publication No. 2015 / 0226886 and the present invention are 92% and 95%, respectively. Thus, lenses according to the present invention exhibit superior cleanability to the "easy to clean" lenses currently on the market that were tested.

[0065] While the present invention has been described with respect to particular embodiments and applications, those skilled in the art will be able to generate additional embodiments and modifications in light of the present teachings without departing from the spirit or beyond the scope of the claimed invention. Accordingly, it should be understood that the drawings and descriptions herein are provided by way of example to facilitate understanding of the invention and should not be construed as limiting its scope.

Claims

1. 1. An easy-to-clean, anti-reflective ophthalmic article comprising: a substrate having a surface; a laminate on the surface, the laminate includes a plurality of alternating low refractive index layers including a metal oxide including silicon dioxide and a high refractive index layer including 1) a metal oxynitride layer including at least one titanium oxynitride layer or zirconium oxynitride layer, or 2) at least one metal oxynitride layer including a titanium oxynitride layer or a zirconium oxynitride layer, or one metal oxide layer including a titanium oxide layer or a zirconium oxide layer; 1. An ophthalmic article, wherein the metal oxynitride layer comprising at least one titanium oxynitride layer or zirconium oxynitride layer is encapsulated between two low refractive index layers of the metal oxide comprising silicon dioxide, providing the ophthalmic article with a surface free energy in the range of 50 to 70 mN / m for 40 days.

2. 10. The ophthalmic article of claim 1, wherein the metal oxynitride layer comprising at least one titanium oxynitride layer or zirconium oxynitride layer is encapsulated between two low refractive index layers comprising a metal oxide comprising silicon dioxide to provide the ophthalmic article with a polar surface energy in the range of 15 to 40 mN / m for 40 days.

3. 10. The ophthalmic article of claim 1, wherein a metal oxynitride layer comprising at least one titanium oxynitride layer or zirconium oxynitride layer is encapsulated between two low refractive index layers comprising a metal oxide comprising silicon dioxide, providing the ophthalmic article with a cleanliness ratio of greater than 90%.

4. 4. The ophthalmic article of claim 3, wherein the metal oxynitride layer comprising at least one titanium oxynitride layer or zirconium oxynitride layer is encapsulated between two low refractive index layers comprising a metal oxide comprising silicon dioxide, providing the ophthalmic article with a cleanliness ratio of 97.63%.

5. An optical laminate that provides easy-to-clean and anti-reflective properties to a surface, 1. An optical stack comprising: at least one high refractive index layer of a metal oxynitride, the high refractive index layer comprising a titanium oxynitride layer or a zirconium oxynitride layer, encapsulated between two low refractive index layers of a metal oxide, the high refractive index layer comprising a titanium oxynitride layer or a zirconium oxynitride layer, encapsulated between the two low refractive index layers of a metal oxide, the high refractive index layer comprising a titanium oxynitride layer or a zirconium oxynitride layer, the high refractive index layer of a metal oxynitride, the high refractive index layer of a metal oxynitride, the high refractive index layer of a metal oxynitride, the high refractive index layer of a metal oxynitride layer or a zirconium oxynitride layer, encapsulated between the two low refractive index layers of a metal oxide, the high refractive index layer of a metal oxynitride layer or a zirconium oxynitride layer ... high refractive index layer of a metal oxynitride layer, the high refractive index layer of a metal oxynitride layer or a high refractive index layer of a metal oxynitride layer,

6. 6. The optical laminate according to claim 5, further comprising a high refractive index layer of a metal oxide containing titanium dioxide or zirconium dioxide.

7. 6. The optical stack of claim 5, wherein the at least one high refractive index layer of a metal oxynitride, comprising the titanium oxynitride layer or the zirconium oxynitride layer, is encapsulated between the two low refractive index layers of a metal oxide, comprising silicon dioxide, to provide the optical stack with a polar surface energy in the range of 15 to 40 mN / m for 40 days.

8. The optical stack according to claim 6 , wherein the high refractive index layer of the metal oxynitride and the high refractive index layer of the metal oxide have the same refractive index.

9. The optical laminate according to claim 6 , wherein the high refractive index layer of the metal oxynitride has a surface roughness higher than a surface roughness of the high refractive index layer of the metal oxide.

10. 1. A method for making an easy-to-clean, anti-reflective ophthalmic article, comprising: providing a substrate having a surface; forming a laminate on the surface; the laminate includes a plurality of alternating low refractive index layers of a metal oxide including silicon dioxide and a high refractive index layer including 1) at least one metal oxynitride layer including a titanium oxynitride layer or a zirconium oxynitride layer, or 2) at least one metal oxynitride layer including a titanium oxynitride layer or a zirconium oxynitride layer, or one metal oxide layer including a titanium oxide layer or a zirconium oxide layer; imparting ease of cleaning to the ophthalmic article by encapsulating at least one metal oxynitride layer comprising a titanium oxynitride layer or a zirconium oxynitride layer between two low refractive index layers of the metal oxide comprising the silicon dioxide, such that the ophthalmic article has a surface free energy in the range of 50 to 70 mN / m for 40 days; The method for producing an ophthalmic article, wherein the ophthalmic article has a cleanliness ratio of greater than 90%.

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