JP6417525B2 - Low reflectivity article and method thereof - Google Patents

Description

Cross-reference of related applications

  No. 61 / 872,043 filed Aug. 30, 2013 under US Patent Act No. 119 and US Patent Application No. 61 / 872,043 filed Oct. 18, 2013 under US Patent Act No. 120. Claims the benefit of priority of patent application No. 14 / 057,638, the contents of which are relied upon and incorporated herein by reference in their entirety.

  The present disclosure includes US Patent Application No. 13 / 440,183, filed April 5, 2012, published as US Patent Application Publication No. 2012/0281292, in common with the present application and the assignee, Provisional Patent Application No. 61 / 557,490, U.S. Patent Application No. 13 / 668,537, filed Nov. 5, 2012, and U.S. Provisional Patent Application No. 61 /, filed Nov. 30, 2012. No. 731,924, U.S. Patent Application No. 13 / 090,561 filed April 20, 2011, U.S. Patent Application No. 13 / 662,789 filed Oct. 29, 2012, and May 2013. Related to U.S. Patent Application No. 13 / 900,659 filed on the 23rd and U.S. Provisional Patent Application No. 61 / 872,037 filed on Aug. 30, 2013, the disclosures of which are , Incorporated herein by reference, benefit of priority is one that does not insist.

  The present disclosure relates generally to low reflectivity or antireflective (AR) surfaces, articles thereof, and methods of making and using the surfaces.

In embodiments, the present disclosure is a single layer of nano-particles; providing a low reflectance film having at least one layer comprising a substantially single layer of (monolayer monolayer) or nanoparticles (near-monolayer).

  In embodiments, the present disclosure provides an article incorporating the low reflectivity film.

In embodiments, the present disclosure provides a method of making the article, the method comprising an integrated or temporary binder layer or binder region on a surface of a substrate, such as by localized heating or irradiation. And a step of depositing a nanoparticle monolayer or substantially monolayer on the integrated binder.

  In an embodiment, the present disclosure provides a method of using the article, for example, in a display device, which includes incorporating the article of the present disclosure into a display device.

1A and 1B respectively show a side view (1A) and a top view (1B) of a substantially single-layer AR film having an exemplary non-dense hexagonal structure. A series of simulated low reflectivity structures for a series of relative binder levels, with the nanoparticle immersion depth (g) of the binder region as a function of the diameter (D) of the spherical or nearly spherical particles. A cross-sectional view is shown. 3A through 3D show a series of graphs showing the reflectance as a function of wavelength as a function of wavelength for a series of binder level thicknesses (g) selected in terms of selected structural parameters. 3E and 3F show a series of graphs of reflectivity as a function of wavelength as a function of wavelength for a series of binder level thicknesses (g) selected in terms of selected structural parameters. 3G to 3J show a series of graphs showing reflectivity as a percentage as a function of wavelength for a series of binder level thicknesses (g) selected in terms of selected structural parameters. 4A to 4D show a series of graphs of the average reflectance contours, average the spectral reflectance from 450 to 650 nm and normalize the reflectance to 200 nm to determine the average reflectance in percent. did. 4E to 4H show a series of graphs of average reflectance contours, averaging 450 to 650 nm spectral reflectance and normalizing the reflectance to 200 nm to determine the average reflectance in percent did. 5A to 5D show plots of preferred design parameters contrasted 6A to 6D show the effect of the difference in particle density on the optical haze. Atomic force microscope of an exemplary glass surface that is dip-coated to provide a substrate surface provided with particles having 120 nm silica spheres and without another binder layer, ie, without another binder layer An example of the height image by is shown. Figure 2 shows data measured for% specular reflection of a group of samples over a wavelength of 300 to 800 nm using two different nanoscale diameter silica spheres coated on an ion exchanged glass substrate. The reflectance% data calculated using the effective refractive index model (EIM) is shown and compared with the data of the ion-exchanged sample described in FIG. FIG. 8 shows a comparison of the EIM results with the measured reflection spectrum of the sample shown in FIG.

  Various embodiments of the present disclosure are described in detail with reference to the drawings, if any. Reference to various embodiments does not limit the scope of the invention, which is limited only by the scope of the claims appended hereto. Moreover, any examples presented in this specification are not intended to be limiting and merely illustrate some of the many possible embodiments of the claimed invention.

In embodiments, the articles of the present disclosure and the methods of the present disclosure for making and using the articles provide one or more advantageous features or aspects including, for example: The features or aspects recited in any claim are generally applicable to all aspects of the invention. Any one or more features or aspects recited in any one claim in combination with any other features or aspects recited in any other claim or claims, or , May be replaced.
Definitions “Antireflection” and similar terms refer to the reduction of all reflections (specular and diffuse) that can be caused by the films or surface treatments of the present disclosure.

  “Reflectance” and similar terms, for example, have an average reflectance of less than 0.1 to 0.2% over a spectral width of at least 100 nm covering at least a portion of the visible wavelength spectrum from 400 to 700 nm. Refers to an article.

  “Binder”, “binder region” and similar terms refer to substrate surface materials that can be used for bonding or bonding reinforcement between surfaces such as between particles or between particles and a glass substrate surface.

  “Integrated binder”, “integrated binder region” and similar terms refer to, for example, a non-adhesive or non-bonded solid surface between surfaces, such as between particles or between a particle and a glass substrate surface. Refers to at least a portion of the substrate surface material that can be temporarily or temporarily changed to an adhesive or bondable viscous liquid surface that can be used for bonding or bond strengthening. An integrated binder is reversible at least once, for example, a temporarily or temporarily realized particle-adhesive or sticky surface or a binding viscous liquid surface to a non-adhesive or non-binding solid surface. It is preferable to be able to change.

“Nanoparticulate monolayer ” and similar terms refer to a single layer of particles, typically in contact with the surface of the substrate, where the particles are generally of an average size or average of about 500 nm or less. The majority of particles having a diameter have a size difference of less than about plus or minus (+/−) 100%. The spacing between the particles is substantially uniform, for example, the difference in spacing between their centers is preferably less than about plus or minus (+/−) 50%.

  The term “including” or similar terms means including but not limited to, ie, including and not including.

  In describing embodiments of the present disclosure, for example, the amount, concentration, volume, processing temperature, processing time, yield, flow rate, pressure, viscosity and similar values of components in the composition and ranges or components thereof The “about” employed to modify the dimensions and similar values of, and ranges thereof is used, for example, to prepare materials, compositions, composites, concentrates, components, articles of manufacture or use formulations. Through typical measurement and handling procedures that are used, through inadvertent errors in these procedures, and through differences in the purity of the starting materials or components used to perform the manufacturing, source, or method, and Refers to a numerical difference that can occur through similar considerations. Also, the term “about” refers to an amount that varies with aging of a composition or formulation having a specific initial concentration or mixing ratio, and mixing or processing of a composition or formulation having a specific initial concentration or mixing ratio. It also contains different amounts.

  “Optional” or “optionally” means that the next described event or situation, condition, or step may or may not occur, and that the description is that event or situation , Conditions, or when a process occurs and when it does not occur.

  As used herein, a noun refers to at least one or more than one subject unless otherwise specified.

  Abbreviations well known to those skilled in the art may be used (eg, “h” or “hrs” for time, “g” or “gm” for grams, “mL” for milliliters, “rt” for room temperature). ”,“ Nm ”for nanometers and similar abbreviations).

  The specific and preferred values disclosed for components, ingredients, additives, dimensions, conditions and similar aspects, and ranges thereof, are for illustration purposes only and other defined or defined values. It does not exclude other values within the specified range. The devices and methods of the present disclosure include any value, or any combination of those values, specific values, more specific values, and suitable values as described in this specification. Including intermediate values and ranges that are explicitly or implied.

  In embodiments, the present disclosure provides a low reflection or anti-reflection (AR) surface that is widely applied, especially in display devices or whenever light is incident on an interface between dissimilar materials (eg, glass and air). provide. A dissimilar interface results in reflected light that is problematic in many applications. In many cases, a film or texture can be applied to the surface to suppress or eliminate these reflections. However, for example, the approach of using vacuum deposited thin films can be expensive. Further, particularly for large area films or complex structures, it is difficult to achieve and control the tolerance for film thickness to remove reflections.

  Another approach to reducing the reflection at the interface is to use texture imparting to the surface. Applying texture to the surface may include, for example, coating the surface with particles. Application of particles to the surface can be achieved, for example, by photolithography, but this approach is expensive and difficult to perform on large sized substrates. Particle adhesion to the surface may involve electrostatic or van der Waals forces, but may be inadequate, resulting in a soft or fragile film. By applying a protective film layer that covers the surface of the substrate provided with the particles, it is possible to further improve the damage resistance of the surface textured with the particles.

  Display devices, and other devices associated with light-related interfaces, can benefit from controlled light scattering in addition to reduced reflectivity. Scattering at or near the interface can cause the reflected image to spread out so as to reduce interference between the reflected image and the image transmitted to the display. By spreading and spreading the light over a range of angles, the brightness of the reflection, that is, the amount of reflected power per unit solid angle, can be reduced.

  In embodiments, the present disclosure provides surface treatments and surface structures that achieve low reflectivity over a wide spectral region. The surface treatment of the present disclosure provides a film in which spherical particles associated with a layer of binding material applied or generated at the interface between the substrate and the particles are substantially monodispersed. Its surface treatment and surface structure depend on subwavelength particles such as nanoparticles. As long as the average particle density (ρ) includes intermediate values and ranges, for example about 1 to 100 / square micrometer, preferably about 5 to 55 / square micrometer, the use of subwavelength particles is It allows for tolerance to density variations and allows a random process to be used to place the particles on the surface. The application of the particles can be achieved, for example, by a low cost and scaleable process, which is a dip coating and similar process.

  In embodiments, the present disclosure provides an article having broadband, low haze, and low reflectivity properties obtained from a random film of spherical particles on a substrate having an integrated binder region or an integrated binder layer. To do. Its properties can be characterized by selected parameters such as average particle density (ρ), particle diameter (D), and integrated binder layer or integrated binder region thickness (g). . Those characteristics are local minima in the parameter space, and as a result, the reflectivity performance does not respond to small changes in the selected parameters. Furthermore, the haze of the uniform integrated binder film can be controlled by minimizing the area of the maximum area to which no particles are applied, i.e., the area without spherical particles.

  In embodiments, the present disclosure provides methods of making the articles of the present disclosure and methods of using the articles of the present disclosure when applied to antireflection.

  In embodiments, the articles and methods of the present disclosure are advantageous in many ways. The method of the present disclosure for producing a low reflectivity surface can be performed on a large area substrate with a scaleable process, resulting in high performance and low cost. The low reflectivity surfaces of the present disclosure and the articles have robust performance for the types of manufacturing differences encountered with low cost processing. Low reflectivity performance persists over a large range of light incident angles and over a wide range of wavelengths.

In embodiments, the present disclosure provides a method of making an article having a range of binder levels, which allows for the selection and realization of a desired level of toughness for a particular application. Since the particles are of sub-wavelength size, differences in local density, such as measured over an area about the square of the wavelength (λ ² ), have little effect on optical performance. This makes the process compatible with, for example, the random nature of dip coating and similar processes.

In embodiments, the present disclosure comprises a substrate, an integrated binder region or layer on at least a portion of the surface of the substrate, and a nanoparticle monolayer partially embedded in the integrated binder region or layer. Antireflective article, wherein the ratio (g: D) of the integrated binder region or layer thickness or particle immersion depth (g) to the nanoparticle monolayer thickness or diameter (D) is intermediate An antireflective article is provided that may be about 1:50 to 3: 5, about 1:50 to 1: 2, or 1:10 to 1: 2, including values and ranges.

In embodiments, each nanoparticle monolayer is independently selected from at least one of glass, polymer, ceramic, composite and similar materials, or combinations thereof.

In embodiments, the integrated binder layer or integrated binder region includes intermediate values and ranges, for example of a substrate having a thickness (t) of 1 nm to 5,000 nm, or 5 nm to 5,000 nm. The surface region may be a nanoparticle monolayer comprising nanoparticles having an average diameter (D) of 50 nm to about 300 nm.

In embodiments, integrated binder layer, 5 nm with a partially submerged nanoparticles immersion depth of about 150 nm (g) into the surface of the substrate from, including the surface of the substrate, the nanoparticle single The layer includes nanoparticles having an average diameter (D) of 50 nm to about 300 nm.

In embodiments, the nanoparticles of the nanoparticle monolayer comprise silica or similar oxide or mixed oxide spheres having an average diameter (D) less than at least one wavelength of visible light.

In embodiments, the nanoparticle monolayer has at least one or alternatively a plurality of at least 0.1 to 1 square micrometer voids or particle areas.

In embodiments, the present disclosure includes the step of applying a monolayer of nanoparticles to an integrated binder region of the surface of the substrate to provide an arbitrary g: D ratio. A method of making a device is provided.

In an embodiment, the step of applying a monolayer of nanoparticles to at least one surface of the substrate is accomplished by dip coating the substrate into an integrated binder and nanoparticle mixture.

In embodiments, the integrated binder region may be, for example, a portion of the surface of the substrate, and the nanoparticle monolayer is partially embedded in the integrated binder region or the integrated binder layer. May be.

In an embodiment, the method further comprises the step of temporarily generating an integrated binder region, for example by temporarily softening the surface of the substrate before applying a monolayer of nanoparticles to the surface of the substrate. The coated nanoparticles may partially sink into the surface of the integrated binder region of the temporarily softened substrate.

In embodiments, the fabrication method includes, for example, applying the monolayer of nanoparticles to at least one temporarily softened surface of the substrate (ie, an integrated binder region or an integrated binder layer). It may include or further include a step of strengthening the substrate by ion exchange before, after, or both before and after.

In embodiments, the present disclosure may include, for example, an integrated binder (ie, the binder includes the same material as the substrate), an optional binder that is an external binder and includes the same or different material as the substrate material, or Providing a low reflectivity surface comprising one or more monolayers of sub-wavelength spherical silica particles attached to the substrate by a combination thereof.

  In the embodiment, “consisting essentially of” or “consisting of” means, for example, an article having a low-reflectivity surface as defined in this specification, or an article having its low-reflectivity as defined in this specification. It may refer to the method of making or using, or a display system incorporating the article as defined herein.

  Articles, display systems, methods of making and using, compositions, formulations, or any apparatus of the present disclosure may be selected from the components or steps recited in the claims, and in addition, the particular reaction selected. Compositions, articles, devices, or methods of making and using the disclosure, such as substances, specific additives or components, specific agents, specific surface modifying materials or conditions, or similar structures, materials or processing variables Other components or processes that do not substantially affect the basic and novel characteristics of the process may be included. Items that may substantially affect the basic characteristics of the components or processes of the present disclosure or may impart undesirable features to the present disclosure include, for example, intermediate values and ranges in this specification. Includes surfaces with undesirable high reflectivity properties, such as exceeding defined and specified values.

  Articles of the present disclosure, methods of making the articles, and methods of using the articles include the components or steps recited in the claims, and, in addition, selected particular article configurations, particular additives or ingredients , Specific agents, specific components or components, specific irradiation, pressure or temperature conditions, or similar structures, materials or process variables, etc. Other components or steps that do not substantially affect the basic and novel characteristics of the method may be included.

Referring to the drawings, FIGS. 1A and 1B represent an exemplary, substantially single layer AR film having a non-dense hexagonal structure, a side view (1A) and a top view (1B), respectively. FIG. 1A is suitable for achieving the minimum reflectivity for a given integrated binder region or integrated binder layer thickness, or equivalent level of immersion or sinking of nanoparticle spheres (g). , Is a cross-sectional view showing the diameter (D) of the spherical particles,
_ns is the refractive index of the substrate,
_ng is the refractive index of the integrated binder region,
n _p is the refractive index of the nanoparticles,
n _o is the refractive index of free space, and p is the pitch or spacing between the centers of adjacent or nearest nanoparticles.

FIG. 2 shows a series of relative integrated binder levels, such as nanoparticle immersion depth or integrated binder region thickness (g) as a function of spherical particle diameter (D). Fig. 4 represents a series of cross-sectional views simulating a minimum reflectivity structure. In the simulation, the three refractive indices ( _ns , _ng and _np ) were all treated as being equal to 1.5.

  FIGS. 3A-3J show structural parameters such as, for example, integrated binder level or degree of particle immersion or sinking (g), average inter-center particle spacing or pitch (p), and spherical particle diameter (D). FIG. 6 shows a series of graphs showing reflectivity as a percentage (%) as a function of wavelength for a series of integrated binder level thicknesses at a preferred design point. In these graphs, the immersion dimension (g) and pitch (p) are shown in units of spherical particle diameter (D). The graph divides the three-dimensional dielectric structure into planar slices, the time domain difference (FDTD) (solid line), which closely simulates the electromagnetic field interacting with the dielectric structure, Two curves of an effective refractive index model (EIM) (broken line) are shown, in which the effective refractive index is determined by the slices, and then the reflectance of the stacked dielectric layers is determined. EIM is an excellent approximation when the lateral scale of the structure is much smaller than the wavelength. FDTD is applicable on a scale where all well-sampled samples are collected. Note how the FDTD model shows resonance at less than 400 nm. This shows that the subwavelength structure assumption for EIM is a good approximation for wavelengths longer than 400 nm, and the FDTD and EIM results agree very well for wavelengths longer than 400 nm. Reinforced. Table 1 shows the ratio of integrated binder region thickness to particle diameter (g / D), pitch for modeled wavelength versus reflectance (FDTD and EIM) results plotted in FIGS. 3A-3J. The ratio of particle diameter to particle diameter (p / D) and particle size diameter (D) are shown in the table.

  In embodiments, an article of the present disclosure having particles bound to a surface can be prepared, for example, by depositing or adding an optional protective film or layer onto the surface provided with the particles. Alternatively, the layer partially coats the particles, eg, fills or covers at least some of the particles.

In embodiments, the antireflective article of the present disclosure may have particles that are completely submerged in an integrated binder region and tied to the surface (ie, g is approximately equal to D). The refractive indices of the integrated binder and particles include, for example, intermediate values and ranges to be equivalent, including 1.1 to 1.8, 1.2 to 1.8, 1.25 to 1.8. 1.3 to 1.8, 1.3 to 1.75, 1.25 to 1.7, 1.3 to 1.65, 1.3 to 1.6, 1.3 to 1.55, 1 .35 to 1.50 etc., or among them. Refractive index of the integral binder region or layer _(n g), the refractive index of the particles _{(n p),} and the refractive index of the substrate _{(n s),} for example, 1.3 ≦ _{n g} ≦ 1.8,1 .3 ≦ n _p ≦ 1.8 and 1.3 ≦ n _s ≦ 1.8 may be selected.

  In embodiments, an article of the present disclosure having particles associated with a surface can be obtained by, for example, softening the substrate, for example, by heating (or irradiation), such as by softening the substrate. It can also be prepared by sinking into the surface of the converted binder layer. In the modeling calculations, a refractive index of 1.5 was used for the integrated binder layer.

  FIGS. 4A to 4H are a series of graphs showing the contours of average reflectance (“<R>”), after averaging the spectral reflectance from 450 to 650 nm to determine the average reflectance in percent. , Normalized at 200 nm. In each graph, the integrated binder level, or the amount that the particle sphere sinks into the substrate surface (integrated binder) or external binder is a certain percentage of the particle diameter (D) of the sphere. The smallest contour curve shows an average reflectance of 0.2% over 450 to 650 nm. The points within the solid contour lines have an average reflectance <R> of less than 0.2%. Other larger curves have average reflectances of 0.5%, 1.0% and 2.0%, respectively. The straight line indicates a hexagonal close-packed structure. The amount of integrated binder expressed as a fraction of the nanoparticle diameter (D) is 16.7% in FIGS. 4A and 4E, 25% in FIGS. 4B and 4F, and FIGS. 4C and 4G. Is 33.3% and in FIGS. 4D and 4H it is 40%. The average density (ρ) (FIGS. 4E to 4H) is related to the average particle spacing or pitch (p) (FIGS. 4A to 4D) via the relationship of equation (1).

ρ = 2 / (√3p ² ) (1)
Figures 5A through 5D show plots of preferred design parameters compared. FIG. 5A shows a range of preferred average center-to-center spacing or pitch (p) between particles, with an integrated binder level thickness (g) range (g / D) over a preferred range of particle diameters (D). ) As a function. FIG. 5B shows the preferred average density (ρ) range of the particles as a function of the integrated binder level thickness (g) range (g / D) versus the preferred diameter (D) range of the particles. ing. FIG. 5C shows the preferred integrated binder level thickness (g) range as a function of the preferred diameter (D) range of the particles. FIG. 5D shows the preferred particle density (ρ) range as a function of the preferred particle diameter (D) range. Each point is a minimum obtained from a contour plot as shown in FIG.

  In embodiments, the particle diameter (D) range may include intermediate values and ranges, for example, 50 nm to about 350 nm, or 100 to 300 nm. In embodiments, the range of pitch (p) between particles may include intermediate values and ranges, for example, 120 to 450 nm. In embodiments, the range of particle average density (ρ) may be, for example, 5 to 55 (per square micrometer), including intermediate values and ranges. In embodiments, the integrated binder level thickness (g) range includes intermediate values and ranges, for example, from 0 (ie, when the binder is integrated into the substrate and there is no separate binder layer itself). 5,000 nm, 5 nm to 5,000 nm, 5 nm to 2500 nm, 5 nm to 1,000 nm, 5 nm to 500 nm, 5 nm to 250 nm, 5 nm to 200 nm, 5 nm to about 150 nm, or 10 nm to 100 nm The layer itself, if g is not equal to zero).

  6A to 6D show the effect of particle density differences on optical haze.

FIG. 6A shows the phase difference between reflected light from an uncoated void region and reflected light from a single layer of silica spheres of diameter (D), and the thickness of the integrated binder layer or the degree of particle sinking. (G) is shown, which is at a low reflectivity design point. It can be seen that as the thickness of the integrated binder layer increases and the preferred diameter increases, at shorter wavelengths, the resonance of the structure begins to affect the differential phase shift.

  FIG. 6B shows the probability density of the uncoated area as a function of the uncoated area, measured for a 120 nm diameter particle coated on the substrate by dip coating.

  FIG. 6C shows the haze (%) from one uncoated area in a 100 micrometer × 100 micrometer coated area as a function of the area of the single uncoated area for a given differential phase.

  FIG. 6D shows the average haze (%) as a function of the differential phase shift between the coated and uncoated areas of the randomly coated surface. In this case, the haze is averaged over the distribution of the non-coating region. The air gap distance, expressed in nanometers, is an additional distance compared to the light field reflected from an area coated with an average particle density that the light field propagates when reflected from an uncoated area. .

FIG. 7 illustrates an exemplary glass surface that is dip coated to provide a substrate surface provided with particles having, for example, 120 nm silica spheres, and without another binder layer, ie, without another binder layer An example of the height image of the atomic force microscope is shown. Bright spots or regions of the image are particles that remain on the top surface of the first monolayer of the membrane (ie, bilayer). The dark area is the particle-free area of the film, and the middle gray area is a monolayer cluster of nanoparticles.

In embodiments, the fabrication method includes, for example, strengthening the substrate by ion exchange before, after, or both before and after applying a monolayer of nanoparticles to at least one temporarily softened surface of the substrate. (Concerning ion exchange methods, for example, the present owner and assignee are common, co-pending later published as US Patent Application Publication No. 2011/0045961) (See US patent application Ser. No. 12 / 856,840 of the application).

  FIG. 8 shows data measured for% specular reflection of a group of samples over a wavelength of 300 to 800 nm using 100 nm (800) and 250 nm (810) diameter silica spheres coated on an ion exchanged glass substrate. including.

  FIG. 9 includes reflectance% data calculated using an effective refractive index model (EIM) and is compared to the ion-exchanged sample data referred to in FIG. The results modeled in EIM shown in FIG. 9 are in good agreement with the shape of the reflection spectrum (ie,% total reflectance) for both particle sizes (ie, 100 nm and 250 nm).

  Even without packing density, very high agreement was observed between the actual and modeled results. The packing density or the ratio of pitch to diameter (p / D) was estimated to be 1.07 from SEM. The selected particle diameter (D) was 100 nm (800) and 250 nm (810).

In FIG. 9, the reflection is calculated at normal incidence (theta = 0), p / D is equal to 1.07, n _s is equal to 1.51, n _p is equal to 1.457, and _ng is 1 It was equal to .52. In addition, an offset of 6% was added to the modeled data to account for backside reflection and scattering. The reflection from one surface was modeled. However, the measurement is performed on an actual glass substrate sample having at least two surfaces or two surfaces. Therefore, additional reflections from the backside need to be added to the data. The added offset does not affect the spectral shape of the curve, but allows convenient comparison of the data represented in the graph.

FIG. 10 shows a comparison of the EIM results (single line curve) (1010) with the measured reflection spectrum (composite curve) (1020) of the sample shown in FIG. Used for. In FIG. 10, D is equal to 120 nm, the ratio of pitch to diameter (p / D) is equal to 1.3, n _s is equal to 1.51, and n _p is equal to 1.46. The curve had a standard 4% offset to account for backside reflections present in the measured data. It is important to note that the model predicts not only the shape of the spectrum, but also the absolute value of the reflection. Both experimental comparisons were consistent with EIM. The close agreement between the modeled and experimental spectral shape and the level of overall reflectivity indicates that the sample preparation process of the present disclosure is predictable with high probability. Experimental observations demonstrate that the model predicts both reflection shape and absolute value.

In an embodiment, the present disclosure includes a random monolayer of sub-wavelength spherical oxide particles, such as silica particles that are substantially monodisperse, with a limited thickness binder region between the particles and the substrate. A low reflectivity surface is provided. Alternatively, the particles may be partially submerged or immersed in the surface of the substrate (ie, an integral binder).

In an embodiment, a single layer of randomly distributed particles covers the surface with an average density (ρ). The average particle density (ρ) is defined as the average number of particles per unit area on the substrate surface, and the average is obtained over a random distribution of particles on the surface. The average particle spacing or pitch (p) is the average center-to-center spacing between adjacent particles, and the average particle density (ρ) is modified (the above formula (1) is modified)
p = √ (2 / (√ (3) ρ)
It is related by.

  The spherical particles have a diameter (D) and the integrated binder layer has a thickness (g). These parameters include, for example, at least the particle diameter (D), the thickness of the integrated binder layer (g), and the pitch (p) to determine the desired structure with the desired AR characteristics. These three parameters are sufficient.

In embodiments, the present disclosure provides a broadband antireflection film having a single layer or Ryakutanso nanoparticles. A “ near monolayer ” is, for example, incomplete with an uncovered surface area of 0.1 to 5%, and a nanoparticle covering a surface area of 95 to 99.9%. Refers to a single layer that is complete. The nanoparticles constituting the monolayer may have, for example, a diameter (D) of 50 to 500 nm, and the diameter is preferably 100 to 300 nm, and more preferably 150 to 280 nm. Nanoparticle monolayers may be composed of nanospheres, hemispheres and similar shapes, or combinations thereof.

  In embodiments, the nanoparticle layer includes intermediate values and ranges, such as less than 1 square micrometer, preferably less than 0.5 square micrometers, more preferably less than 0.25 square micrometers, such as about 0. .1 to about 1.5 square micrometers may have voids or gaps that are one or more regions free of particles.

  In embodiments, the integrated binder region or layer may include the substrate itself. That is, an integrated binder region or binder layer may be temporarily softened or otherwise, for example, to allow deposited or applied particles to be partially immersed or submerged on or in the softened substrate surface. Having at least part of the surface of the substrate modified in a way, then the softened substrate may be resolidified, for example by cooling at ambient temperature.

At the interface between the nanoparticle monolayer and the substrate, there is disposed at least one integrated binder region having a refractive index that is the same or equivalent to the refractive index of the substrate, the nanoparticles, or both the substrate and the nanoparticles. May be. The refractive index of the integrated binder region is determined by, for example, including an additive or dopant in the integrated binder region while the integrated binder region is temporarily generated, such as by softening. It may be changed so as to be different from the refractive index. This integrated binder region reduces reflection or broadens the low reflection band produced by the AR film and helps attach or adhere the particles to the substrate. The transparent substrate may be glass or other transparent material and similar materials such as, for example, polymers, plastics, composites, transparent sol-gel products, transparent glass-ceramic materials, or combinations thereof. Good.

  The slope of the preferred particle density (ρ) as a function of particle diameter (D) gives a measure of the sensitivity of the surface structure to variations in these two parameters (particle density and particle diameter). For small spheres having a diameter of 50 to about 200 nm, the small spheres correspond to thin integrated binder regions, but the steep slope as shown in FIG. 5D indicates that the surface structure has an average particle density (ρ ) Is relatively unresponsive. For large spheres having a diameter of 200 to about 500 nm, the large sphere corresponds to a thick, integrated binder region, indicating that the surface structure becomes insensitive to the diameter of the spherical particles, The structure means that a non-monodisperse distribution of spherical particles could be employed. In addition, contour plots of average reflectance, such as FIGS. 4A-4H, can be used to determine sensitivity to changes in diameter (D) and average particle spacing (p).

  Anti-reflection properties for display devices are particularly important in the visible spectrum. However, through scale invariance, the structures of the present disclosure can be applied to applications in any wavelength range. For higher index materials, the sphere scale or size may be reduced to provide the same optical path and relative index gradient as included in the structures disclosed herein.

Calculations were performed for all materials having the same (equal) or substantially the same refractive index (n) or equivalent refractive index equal to 1.5. It has been observed that small changes in the refractive index of the sphere, substrate, or integrated binder region do not lead to significant deviations from the design key points and structures of the present disclosure. In this way, similar performance can be expected for refractive indices of 1.4 to 1.6. The approach to developing structures for higher (or lower) refractive index materials remains effective, but in that case the refractive index and haze are expected to deviate from the structures disclosed herein. sell. Haze is a measure of diffuse scattering (that is, angular scattering deviated by more than 2.5 degrees from the specular direction) divided by total scattering. For structures with periodic subwavelengths, all diffraction orders are evanescent, so there is no scattering. Scattering from a collection of subwavelength particles only occurs when the particles deviate from the periodic grating. The images of particles deposited on the surface with the low-cost manufacturing process of the present disclosure show particles that mainly collect in monolayer clusters, with uncoated voids between the clusters. The reflected light from the gap accumulates a phase shift different from the phase shift of the reflected light from the particle array surrounding the non-coating region. This differential phase shift depends on the wavelength and structure. The differential phase shift is shown in drawings such as FIG. 6A. For suitable design parameters with an integrated binder level (g) of less than about 45% of the preferred particle diameter (D) or 0.45 × D, the differential phase shift is similar for all structures. The haze produced by the uncoated regions surrounded by the cluster of particles increases with increasing void area and differential phase shift. Since the differential phase shift of low reflectivity structures is very similar, haze is not significantly affected by structure selection, but will be most affected by the area probability density of the uncoated regions.

  The haze on the surface of the particle coating can be estimated by summing the products obtained by multiplying the haze generated by a predetermined uncoated area by the probability of having an uncoated area of that size. Thus, this sum calculates the predicted average haze of the collection of open areas following the uncovered area probability density.

  Since the low reflectance structure of the present disclosure has substantially the same differential phase shift between the coated region and the coated region on the surface, the average haze can be determined mainly by the probability density function of the uncoated region. . If particle coating treatment for particle diameters between 100 and 300 nm produces uncoated regions with similar area probability density, then the expected haze from these structures is similar. However, if the relative area of the void varies with particle size, then the void area will increase in proportion to the relative increase in the square of the particle diameter (eg, when the diameter is 100 to 300 nm, Haze will increase 9 times). Low reflectance or AR film structures of the present disclosure having smaller diameter particles should exhibit lower haze values than larger diameter particle structures. Under the assumption that the film of particles is scale invariant over a range of diameters from 100 to 300 nm, at different scales the relative strength of the different self-organizing forces acting on the particles is of relative importance. The assumption may be flawed because it may change at For example, the surface area of a sphere increases approximately 10 times and the volume increases 27 times when the diameter of the sphere is changed from 100 nm to 300 nm.

  Furthermore, haze will be more drastically affected by uncoated areas where the area is equal to the square of the wavelength or larger. Random coating processes that have a small uncoated area compared to the square of the wavelength, or that have a relatively low probability of having an uncoated area that is greater than or less than the square of the wavelength, are Will produce less haze than a surface with a large uncoated area. This is mainly due to the optical resolution of the optical far field. The far field does not contain information about the lateral scale, which is small compared to the wavelength, so the small air gap does not affect the far field and is invisible to the observer using the far field.

  In embodiments, the integrated binder region can be applied to a variety of known methods such as heating, irradiating, rubbing, mechanical impact, stamping and similar methods, or combinations thereof, for example, on the surface of a transparent substrate. It can be temporarily generated by softening in any way.

Nanoparticle monolayers may be deposited from water or solvent-based suspensions, for example, by dip coating, spin coating, spray coating and similar methods, or combinations thereof. The nanoparticle monolayer may optionally be fused to the substrate surface, for example by thermalization of the substrate surface, thermalization of the particles, or both before or after the nanoparticles are deposited on the substrate. . Nanoparticle monolayers optionally include, for example, a very thin layer, for example by adding a thin layer on the particle surface or at the interface between the integrated binder region and the nanoparticles. It may be fused to the surface. For example, a very thin layer having a thickness of 1 to 10 nm, for example of siloxane, sol-gel SiO ₂ or fumed silica soot material or even other materials applied by dip coating or spray coating. , May act as a secondary binder material.

In embodiments, a nanoparticle monolayer may first be formed on an alkali silicate glass substrate using, for example, dip coating, spin coating, spray coating, and similar methods, or combinations thereof. The nanoparticle monolayer may optionally be fused by thermal sintering to a glass surface such as alkali silicate glass. The alkali silicate glass is then optionally ion-exchanged with smaller ions in the glass with larger ions, eg, the original sodium ions are exchanged with potassium ions. May be chemically enhanced.

In embodiments, the glass substrate or glass article comprises one of soda lime glass, alkaline earth aluminosilicate glass, alkali aluminosilicate glass, alkali borosilicate glass, and combinations thereof, or substantially from Or may consist of. In an embodiment, the glass article may be, for example, an alkali aluminosilicate glass having the following composition. Composition, 60 to 72 mol% of _SiO 2, 9 to 16 mol% of _Al 2 _O 3, 5 to 12 mole% _B 2 _O 3, 8-16 mol% Na ₂ O and 0 to 4 mol% K ₂ O, the ratio is as follows.

The alkali metal modifier is an alkali metal oxide. In embodiments, the alkali aluminosilicate glass substrate, for example, 61 to 75 mol% of _SiO 2, 7 to 15 mol% of _Al 2 _O 3, 0 to 12 mol% of _B 2 _O 3, 9 to 21 mol% Na ₂ O, 0-4 mol% K ₂ O, 0-7 mol% MgO and 0-3 mol% CaO. In embodiments, the alkali aluminosilicate glass substrate, for example, 60 to 70 mol% of _SiO 2, having 6 to 14 mol% of _Al 2 _O 3, 0 to 15 mol% of _B 2 _O 3, 0 to 15 mol% Li ₂ O, 0-20 mol% Na ₂ O, 0-10 mol% K ₂ O, 0-8 mol% MgO, 0-10 mol% CaO, 0-5 mol% ZrO ₂ , 0-1 mol% of _SnO 2, a _Sb 2 _{O 3} less than 0 to 1 mol% _CeO 2, less than 50ppm of _As 2 _{O 3} and of 50pp, 12 _{mol% ≦ Li 2 O + Na 2} O + K 2 O ≦ 20 mol % And 0 mol% ≦ MgO + CaO ≦ 10 mol%. In embodiments, the alkali aluminosilicate glass substrate, for example, 64 to 68 mol% of _SiO 2, 12 to 16 mol% of _Na 2 O, 8 to 12 mole% _Al 2 _O 3, 0-3 mol% B ₂ O ₃ , 2-5 mol% K ₂ O, 4-6 mol% MgO and 0-5 mol% CaO, 66 mol% ≦ SiO ₂ + B ₂ O ₃ + CaO ≦ 69 mol%, Na ₂ O + K ₂ O + B ₂ O ₃ + MgO + CaO + SrO> 10 mol%, 5 mol% ≦ MgO + CaO + SrO ≦ 8 mol%, (Na ₂ O + B ₂ O ₃ ) —Al ₂ O ₃ ≦ 2 mol%, 2 mol% ≦ Na ₂ O—Al ₂ It may be O ₃ ≦ 6 mol% and 4 mol% ≦ (Na ₂ O + K ₂ O) —Al ₂ O ₃ ≦ 10 mol%. In the embodiment, the alkali aluminosilicate glass is, for example, 50 to 80% by mass of SiO ₂ , 2 to 20% by mass of Al ₂ O ₃ , 0 to 15% by mass of B ₂ O ₃ , or 1 to 20% by mass. Na ₂ O, 0-10 wt% Li ₂ O, 0-10 wt% K ₂ O and 0-5 wt% (MgO + CaO + SrO + BaO), 0-3 wt% (SrO + BaO) and 0-5 wt% (ZrO ₂ + TiO ₂ ), and 0 ≦ (Li ₂ O + K ₂ O) / Na ₂ O ≦ 0.5 may be satisfied. In the embodiment, the alkali aluminosilicate glass may be substantially free of lithium, for example. In embodiments, the alkali aluminosilicate glass may be substantially free of, for example, at least one of arsenic, antimony, barium, or combinations thereof. In embodiments, the glass is optionally from 0, such as Na ₂ SO ₄ , NaCl, NaF, NaBr, K ₂ SO ₄ , KCl, KF, KBr, SnO ₂ and similar materials, or combinations thereof. It may be batch processed with 2 mol% of at least one fining agent.

  In embodiments, the selected glass can be formed, for example, by methods such as downdraw, ie, known slot draw or fusion draw processing. In these cases, the glass may have a liquidus viscosity of at least 130 kpoise. Specific examples of alkali aluminosilicate glasses claim priority from US Provisional Patent Application No. 60 / 930,808, filed May 22, 2007, which is in common with the present owner and assignee, 2007 US patent application Ser. No. 11 / 888,213 entitled “Down-Drawable, Chemically Strengthened Glass for Plate”, filed July 31, 2007, US Provisional Patent Application No. 11 / 888,213, filed November 29, 2007 US patent application Ser. No. 12/2, entitled “Glasses Having Improved Toughness and Scratch Resistance,” filed Nov. 25, 2008, claiming priority to 61 / 004,677. No. 77,573, US Provisional Patent Application No. 61 / 067,130 filed Feb. 26, 2008, Descendants et al., “Fining Agents for Silicate Glasses”, filed Feb. 25, 2009, of Dejneka et al. No. 12 / 392,577, entitled US Provisional Patent Application No. 61 / 067,732, filed Feb. 29, 2008, and filed on Feb. 26, 2009. US Patent Application No. 12 / 393,241 entitled “Ion-Exchanged, Fast Cooled Glasses” by Dejneka et al., US Provisional Patent Application entitled “Chemically Tempered Cover Glass” filed Aug. 8, 2008. 61/08 US Patent Application No. 12 / 537,393, August 2009, Barefoot et al. Entitled “Strengthened Glass Articles and Methods of Making,” filed Aug. 7, 2009, claiming priority US Provisional Patent Application No. 61 / 235,767 titled “Crack and Scratch Resistant Glass and Enclosures Made Therefrom” filed on July 21, 2009, and “Djnekaon et al.” Described in US Provisional Patent Application No. 61 / 235,762 entitled “Compatible Glasses for Down Draw”. There.

  The glass surfaces and sheets described in the specific examples below may be glass substrates that can be coated with any suitable particles, or similar substrates such as ion-exchanged substrates, for example listed in Table 2. Glass compositions 1 to 11 or combinations thereof may be included.

Shinotsuka U.S. Pat. No. 8,202,582 refers to a two-dimensional dense microstructure used as a single particle film etch mask to make an anti-reflective surface. The etching mask is produced by a dropping process, an evaporation process, and a transfer process in which the single particle film is transferred to the substrate. Single particle film etching mask
D (%) = | B−A | × 100 / A
Has a particle array misregistration D (%), defined by, where D (%) is 10% or less, A is the average diameter of the particles, and B is the average pitch between particles in the film.

  The following examples serve to more fully describe the method of using the above disclosure and to further illustrate the best modes contemplated for carrying out various aspects of the disclosure. These examples do not limit the scope of the disclosure, but rather are presented for purposes of illustration. The examples further describe how to prepare the disclosed.

Example 1 (virtual) preparation of a surface provided with particles
Preparation of a surface provided with particles having a substantially uniform spacing or spacing distance between adjacent particles, ie having a non-dense hexagonal arrangement, and an integrated binder layer. Numerous methods have been clarified for producing non-dense nanoparticle monolayers on various substrates while controlling the spacing between the particles, including those that exhibit antireflection effects. These methods are described in transmissive graphs on lithographic patterns (e.g. Hoogenboom, et.al., "Template-Induced Growth of Close-Packed and Non-Closed-Packed Colloidal Crystallization Solvent Ev. 2, p. 205, 2004), dip coating of hydrogel spheres that can shrink during drying or heating after deposition (Zhang, et.al. “Two-Dimensional Non-Close-Packing Array Delivered from Self-Assembly. of Biomineralized Hydrospheres and T heir Patterning Applications ”, Chem. Mater. 17, p. 5268, 2005, FIG. 3 and related text), SiO ₂ nanosphere spin-coating, and shear alignment, optionally with this template (See Venkatesh, et. Al., “Generalized Fabrication of Two-Dimensional Non-Closed-Packed Colloidal Crystals,” Langmuir, 23, p. 8231, 2007, and related text.) An electrostatically controlled self-assembly that is transferred to a substrate at the air-water or alkane-water interface, optionally very thin (about 17 m) adhesive layer (Ray, et.al., “Submicrometer Surface Patterning Using Interfacial Colloidal Self-Assembly”, Langmuir, 25, p. 7265, 2009, FIG. 8 and related a. Al., "Development of a Colloidal Lithography Method for Patterning Nonplanar Surfaces," Langmuir, 26, p.16662, 2010). However, these previous studies have not identified the desired relationship between particle size, particle spacing, and particle subsidence into the integrated binder region of the substrate. It is specified in this disclosure to achieve excellent low reflection performance for visible light, along with enhanced durability by optionally subsiding or sintering the particles.

D particle diameter p pitch g integrated binder region thickness ρ particle density

Claims (5)

A polymer substrate reinforced by ion exchange ;
An integral polymer binder region on at least a portion of the surface of the polymer substrate;
A nanoparticle monolayer partially embedded in the binder region of the integrated polymer;
An anti-reflective article comprising
The ratio (g: D) of the thickness (g) of the binder region of the integrated polymer to the thickness or diameter (D) of the nanoparticle monolayer is 1:50 to 3: 5;
The integrated polymer binder region has the same composition as the polymer substrate;
An antireflection article, wherein the nanoparticles in the nanoparticle monolayer are non-densely arranged with an average particle density of 1 to 100 particles / square micrometer .   The antireflective article according to claim 1, wherein the nanoparticles of the nanoparticle monolayer are selected from at least one of glass, polymer, ceramic, composite, or combinations thereof.   The antireflection article according to claim 1 or 2, wherein the partially embedded nanoparticle monolayer comprises nanoparticles having an average diameter of 50 nm to 300 nm.   The integrated polymer binder region comprises a surface of the polymer substrate having nanoparticles partially embedded in the surface of the polymer substrate at an immersion depth of 1 nm to 150 nm, the nanoparticle monolayer comprising: The antireflection article according to claim 1, comprising nanoparticles having an average diameter of 50 nm to 300 nm. A method for producing an antireflective article according to any one of claims 1 to 4,
Applying the monolayer of nanoparticles to the integrated polymer binder region comprising at least one temporarily softened surface of the polymer substrate; and applying the monolayer of nanoparticles to the polymer substrate. Strengthening the polymer substrate by ion exchange before, after, or both before and after application to at least one temporarily softened surface.

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