Anti-reflective and anti-glare glass laminates

Abstract

A method for forming a glass laminate comprises providing a substrate having a core layer and at least one cladding layer; heat-treating the substrate at a temperature such that the at least one cladding layer phase-separates after the heat treatment; and etching the substrate for at least 10 seconds. A phase-separated glass laminate comprises a substrate having a core layer and at least one cladding layer such that the glass laminate has a transmittance of at least 96%, and the at least one cladding layer comprises a grain size in the range of 10 nm to 1 μm, or a graded glass index greater than 5 nm.

Description

[0001] This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Serial No. 63 / 024,784, filed on May 14, 2020, the entire contents of which are incorporated herein by reference. Background Art

[0002] 1. Field

[0003] The present disclosure relates to anti-reflective (AR) and anti-glare glass laminates having improved optical properties.

[0004] 2. Technology

[0005] Reflection of light on non-AR coated glass surfaces occurs at the air-glass interface and can reflect up to 8% of light at normal incidence, as predicted by the Fresnel equation. Conventional techniques for minimizing reflections include using an AR coating disposed on the glass surface to reduce the intensity of reflected light. Antireflective coatings typically contain multiple layers (one or more) of low and high refractive index materials that destructively interfere with the different reflections within the stack. An alternative to AR coatings is AG treatment by etching the surface of the patterned glass, textured coatings, or bulk scatterers to scatter the incident light away from the specular direction.

[0006] However, both conventional AR and AG technologies are (A) cost and time-constrained (e.g., AR coatings typically require multiple coats of different compositions); (B) can be difficult to control; and (C) challenging to jointly optimize (i.e., AR coating and AG properties can counteract each other's contributions).

[0007] The present application discloses improved anti-reflective (AR) and anti-glare (AG) glass laminates having enhanced optical performance in display and sensor applications. Summary of the Invention

[0008] In some embodiments, a method of forming a glass laminate includes: providing a substrate having a core layer and at least one cladding layer; heat treating the substrate at a temperature such that the at least one cladding layer is phase separated after the heat treatment; and etching the substrate for at least 10 seconds.

[0009] In an aspect that may be combined with any other aspect or embodiment, the substrate is formed by a fusion lamination process.

[0010] In one aspect that may be combined with any other aspect or embodiment, prior to the heat treatment, the core layer is an amorphous core layer and the at least one cladding layer is an amorphous cladding layer.

[0011] In an aspect that may be combined with any other aspect or embodiment, the heat treatment is performed at a temperature in the range of 400°C to 1300°C.

[0012] In one aspect that may be combined with any other aspect or embodiment, the heat treatment is performed for a time in a range of 1 min to 200 hr.

[0013] In one aspect that may be combined with any other aspect or embodiment, the heat treatment is performed for a time in the range of 4 hr to 64 hr.

[0014] In one aspect that may be combined with any other aspect or embodiment, the etching process is performed for a time in a range of 1 sec to 24 hr.

[0015] In one aspect that may be combined with any other aspect or embodiment, the etching is performed using a wet chemical etchant selected from at least one of HCl, HNO3, H2SO4, H3PO4, H3BO3, HBr, HClO4, HF, acetic acid, citric acid, NH4F, acidic ammonium fluoride, LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2, H2O, or a combination thereof.

[0016] In one aspect that may be combined with any other aspect or embodiment, the etchant is present at a concentration of at least 0.1 vol. % of the total solution volume.

[0017] In one aspect that may be combined with any other aspect or embodiment, the etchant is present in a concentration in the range of 0.25 vol. % to 5 vol. % of the total solution volume.

[0018] In one aspect that may be combined with any other aspect or embodiment, the etching is performed using a dry etching process selected from at least one of ion beam etching, plasma etching, reactive ion etching, or a combination thereof.

[0019] In one aspect that may be combined with any other aspect or embodiment, the phase separated at least one coating layer has a grain size in the range of 10 nm to 1 μm.

[0020] In an aspect that may be combined with any other aspect or embodiment, the at least one cladding layer and the core layer phase separate after the heat treatment.

[0021] In one aspect that may be combined with any other aspect or embodiment, the phase-separated at least one cladding layer has a grain size that is smaller than a grain size of the phase-separated core layer.

[0022] In some embodiments, a phase separated glass laminate comprises: a substrate having a core layer and at least one phase separated cladding layer, wherein the glass laminate has a transmittance of at least 96%, and wherein the at least one cladding layer comprises a grain size in a range of 10 nm to 1 μm, or a graded glass index greater than 5 nm.

[0023] In one aspect that may be combined with any other aspect or embodiment, the core layer is a phase separated core layer.

[0024] In one aspect that may be combined with any other aspect or embodiment, the at least one phase-separated cladding layer has a grain size that is smaller than a grain size of the phase-separated core layer.

[0025] In one aspect that may be combined with any other aspect or embodiment, the glass laminate has a % transmission of at least 98% and an image clarity of less than 30%.

[0026] In one aspect that may be combined with any other aspect or embodiment, the at least one cladding layer has a graded glass index in the range of 1 μm to 5 μm.

[0027] In one aspect that may be combined with any other aspect or embodiment, the average coefficient of thermal expansion (CTE) of the at least one coating layer is 包覆 ) is different from the average thermal expansion coefficient (CTE) of the core layer 核心 ). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present disclosure will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0029] Figure 1 A three-layer substrate according to some embodiments is described that includes a core layer interposed between a first cladding layer and a second cladding layer.

[0030] Figure 2 A fused draw laminated glass processing process according to some embodiments is described.

[0031] Figure 3A and Figure 3B The incident light is transmitted through the Figure 2 Before processing ( Figure 3A ) and after treatment ( Figure 3B )'s cover glass transmission and Fresnel reflection.

[0032] Figures 4A-4F Illustrated are images of coated portions of laminates after heat treatment at different times and temperatures, according to some embodiments.

[0033] Figures 5A-5E Scanning electron microscope (SEM) images illustrating phase separation in the coated portion of a laminate after heat treatment at different times and temperatures, according to some embodiments.

[0034] Figures 6A-6D Measurement of optical properties of a laminate as a function of temperature conditions in a heat treatment step and an etching step according to some embodiments is described.

[0035] Figure 7 The total transmittance (%) of a control sample and a test sample according to some embodiments, the test sample being heat-treated at 700° C. for 64 h and then etched with 2 vol. % HF for 30 sec, is illustrated.

[0036] Figures 8A-8D Total transmittance (%) and distinctness of image (DOI) as a function of etching time and acid concentration are illustrated according to some embodiments. DETAILED DESCRIPTION

[0037] Reference will now be made in detail to the exemplary embodiments illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. The components in the drawings are not necessarily drawn to scale, with emphasis instead being placed on illustrating the principles of the exemplary embodiments. It should be understood that this application is not limited to the details or methods set forth in the specification or shown in the drawings. It should also be understood that the terminology is used for descriptive purposes only and should not be considered as limiting.

[0038] Therefore, any examples set forth in this specification are illustrative rather than restrictive and set forth only some of the many possible embodiments of the claimed invention. Other suitable modifications and adjustments of the various conditions and parameters that are commonly encountered in the art and that will be apparent to those skilled in the art are within the spirit and scope of the present disclosure.

[0039] definition

[0040] Percent transmittance (%) is defined as the percentage of incident light that passes through the thickness of a material. Percent reflectance (%) is defined as the percentage of incident light that is reflected from an interface when light travels from one medium to another (e.g., from air to glass). Both % transmittance and % reflectance can also be defined for systems with multiple interfaces, including discontinuous and gradient interfaces.

[0041] Distinctness of image (DOI) is a quantification of the deviation of the direction of light propagation from the regular direction due to scattering during transmission or reflection.

[0042] Gloss is defined as a measurement proportional to the amount of light reflected from a surface, determining how bright a surface appears. Haze reduces reflective contrast and causes halos to appear around light sources; these unwanted effects can significantly reduce visual quality. Phase separation is defined as the separation of a homogeneous medium into two or more different homogeneous materials, typically with different chemical properties. The refractive index of glass is defined as the refractive index of a material.

[0043] The coefficient of thermal expansion (CTE) is defined as the coefficient of thermal expansion of the glass composition averaged over the temperature range of about 20°C to about 300°C.

[0044] The terms “include”, “includes” and the like mean covering but not limited to, that is, inclusive rather than exclusive.

[0045] As used herein, the terms "approximately," "about," "substantially," and similar terms are intended to have a broad meaning consistent with the common and acceptable usage by those skilled in the art to which the subject matter of the present disclosure belongs. Those skilled in the art who review the present disclosure should understand that these terms are intended to allow for a description of certain features described and claimed without limiting the scope of those features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations to the subject matter described and claimed are considered to fall within the scope of the present invention as set forth in the appended claims.

[0046] For example, when modifying the quantitative, concentration, volume, process temperature, process time, yield, flow rate, pressure, viscosity, etc. values and ranges thereof for ingredients in the compositions used to describe embodiments of the present disclosure, or the size, etc. values and ranges thereof for components, "about" or similar terms refer to numerical variations that may occur, for example, by commonly measured and processed procedures used to prepare materials, compositions, compounds, concentrates, components, manufactured articles, or formulations for use; by unintentional errors in these procedures; by differences in the preparation, source, or purity of the starting materials or ingredients used to perform the process; and similar considerations. The term "about" (or similar terms) also includes amounts that vary due to aging of a composition or formulation having a specific initial concentration or mixture, and amounts that vary due to mixing or processing of a composition or formulation having a specific initial concentration or mixture.

[0047] As used herein, "optional," "optionally," and the like are intended to indicate that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not. Unless otherwise stated, the indefinite articles "a" or "an" and the corresponding definite articles "the" as used herein mean at least one, or one or more.

[0048] References herein to element positions (e.g., "top," "bottom," "above," "below," etc.) are intended only to describe the orientation of the various elements in the figures. It should be noted that the orientation of the various elements may differ according to other exemplary embodiments, and such variations are intended to be encompassed by the present disclosure.

[0049] Abbreviations well known to those skilled in the art may be used (e.g., "h" or "hr" for hours, "g" or "gm" for grams, "mL" for milliliters, "rt" for room temperature, "nm" for nanometers, etc.).

[0050] The specific and preferred values disclosed for components, ingredients, additives, dimensions, conditions, times, and other aspects and their ranges are for illustration only; they do not exclude other defined values or other values within defined ranges. The compositions, articles, and methods of the present disclosure may include any value or any combination of the values, specific values, more specific values, and preferred values described herein, including explicit or implicit intermediate values and ranges.

[0051] For the use of substantially any plural and / or singular terms herein, those skilled in the art can convert from plural to singular and / or from singular to plural according to the context and / or application. For clarity, various singular / plural permutations and combinations may be explicitly set forth herein.

[0052] As explained above, conventional techniques for reducing reflections on glass surfaces include the use of AR coatings and AR textures. However, both traditional AR and AG techniques are (A) cost and time-constrained (e.g., AR coatings typically require multiple coats of different compositions); (B) can be difficult to control; and (C) challenging to jointly optimize (i.e., AR coatings and AG properties can counteract their respective effects).

[0053] In this disclosure, a new approach to using a cladding layer of laminated glass as an AR / AG surface is described. To achieve this goal, a phase separation chemistry of the cladding layer in AR applications was developed using a two-step process (including etching). For AG applications, only a one-step process is required (no etching). As a result, laminated glass in AG applications can be formulated with larger grain sizes in the core layer and smaller grain sizes in the cladding layer compared to glass laminates in AR applications. A heat treatment and surface etching cycle was developed to form a gradient index material with improved optical properties (e.g., total reflectivity of about 1% on the surface, lower gloss and lower DOI) for display applications (e.g., automotive interiors, laptop covers, smart watches, etc.). The laminated structure of the glass is stronger than a single glass system. In some embodiments, at least one of the cladding layer, core layer, or a combination thereof can be phase separated at different grain sizes to optimize the cover glass design for a specific application.

[0054] Now refer to the figure, Figure 1 A three-layer substrate (i.e., a laminate) according to some embodiments is described, which includes a core layer 102 inserted between a first cladding layer 104a and a second cladding layer 104b. The core layer 102, the first cladding layer 104a, and the second cladding layer 104b independently include a glass-based material (e.g., a glass material, a glass-ceramic material, a ceramic material, or a combination thereof). In some embodiments, the core layer 102 includes a glass composition that is different from the glass composition of the first cladding layer 104a and the second cladding layer 104b. The first cladding layer 104a and the second cladding layer 104b can be formed by the first cladding glass composition and the second cladding glass composition, respectively. In some embodiments, the first cladding glass composition and the second cladding glass composition can be the same material. In other embodiments, the first cladding glass composition and the second cladding glass composition can be different materials.

[0055] Figure 1A core layer 102 is illustrated having a first surface 102a and a second surface 102b opposite the first surface 102a. A first cladding layer 104a is directly fused to the first surface 102a of the core layer 102, and a second cladding layer 104b is directly fused to the second surface 102b of the core layer 102. The glass cladding layers 104a and 104b can be fused to the core layer 102 without any additional materials, such as adhesives, polymer layers, cladding layers, etc., being disposed between the core layer 102 and the cladding layers 104a and 104b. Thus, in this case, the first surface 102a of the core layer 102 is directly adjacent to the first cladding layer 104a, and the second surface 102b of the core layer 102 is directly adjacent to the second cladding layer 104b. In some embodiments, the core layer 102 and the glass cladding layers 104a and 104b are formed by a fusion lamination process (e.g., a fusion drawing process). A diffusion layer (not shown) may be formed between the core layer 102 and the cladding layer 104a, or between the core layer 102 and the cladding layer 104b, or both.

[0056] The first and second coating layers can be any composition that phase separates in a spinodal manner to produce a porous matrix. For example, the first and second coating layers can be formed from a composition comprising silicon dioxide (SiO2) at a concentration in the range of 45 wt.% to 75 wt.% (e.g., ˜60 wt.%), aluminum oxide (Al2O3) at a concentration in the range of 8 wt.% to 19 wt.% (e.g., ˜12 wt.%), boron trioxide (BO3) at a concentration in the range of 5 wt.% to 23 wt.% (e.g., ˜18 wt.%), an alkali metal oxide (e.g., Li2O, Na2O, K2O, Rb2O, etc.) at a concentration in the range of 3 wt.% to 21 wt.%, and an alkaline earth metal oxide (e.g., MgO (˜1-5 wt.%), CaO (˜1-10 wt.%), SrO (˜1-5 wt.%), etc.) at a concentration in the range of 1 wt.% to 15 wt.%. The cladding layer can be substantially free of arsenic (As) and cadmium (Cd) to provide a degradation rate of the cladding layer that is at least ten times greater than the degradation rate of the core layer. In some instances, the cladding layer can be an aluminosilicate glass with a high B2O3 content. The thickness of the first cladding layer and the second cladding layer can each independently be in the following range: 50 μm to 1000 μm, or 50 μm to 750 μm, or 50 μm to 500 μm (e.g., 400 μm), or 50 μm to 250 μm, or 100 μm to 750 μm, or 150 μm to 600 μm, or 200 μm to 500 μm, or 500 μm to 1000 μm, or 500 μm to 750 μm, or 750 μm to 1000 μm, or any value or range disclosed herein.

[0057] The core layer may be formed of at least one of the following: alkaline earth boroaluminosilicate glass (e.g., Corning Eagle ), Corning Glass, Corning Iris TM Glass or Corning Glass. For example, the core layer may be formed from glass having the following composition: 79.3 wt.% SiO2, 1.6 wt.% Na2O, 3.3 wt.% K2O, 0.9 wt.% KNO3, 4.2 wt.% Al2O3, 1.0 wt.% ZnO, 0.0012 wt.% Au, 0.115 wt.% Ag, 0.015 wt.% CeO2, 0.4 wt.% Sb2O3, and 9.4 wt.% Li2O. In some examples, the core layer may be formed from a glass composition falling within the ranges described above for the first and second cladding layers. For example, the core layer may be formed from a glass having the following composition: 56.57 wt.% SiO2, 16.75 wt.% Al2O3, 10.27 wt.% B2O3, 4.54 wt.% CaO, 3.18 wt.% K2O, 3.79 wt.% MgO, 4.74 wt.% SrO. In some embodiments, the core layer comprises at least one of: Corning Eagle Glass or Corning Iris TM Glass, for example, due to its ultra-low natural fluorescence. The thickness of the core layer can be in the following range: 1 μm to 200 μm, or 5 μm to 150 μm, or 10 μm to 100 μm (e.g., 50 μm), or 25 μm to 75 μm, or 100 μm to 200 μm, or 100 μm to 150 μm, or 150 μm to 200 μm, or 1 μm to 100 μm, or 1 μm to 50 μm, or 50 μm to 100 μm, or any value or range of the present disclosure. The core layer provides structural strength to the cladding layer through a stress concentration layer at the core layer / cladding layer interface.

[0058] In some examples, the core layer may be formed of a glass composition having a thermal conductivity greater than or equal to about 40×10 -7 The average thermal expansion coefficient (CTE 核心 In some examples, the glass composition of the core layer has an average CTE in the range of 20°C to 300°C. 核心 can be greater than or equal to about 60×10 -7 In some examples, the glass composition of the core layer has an average CTE in the range of 20°C to 300°C. 核心 can be greater than or equal to about 80×10 -7In some examples, the average thermal expansion coefficient (CTE) of the first and second coating layers is 包覆 ) is different from the average thermal expansion coefficient (CTE) of the core layer 核心 In some examples, the average coefficient of thermal expansion (CTE) of the first and second coating layers is 包覆 ) is lower than the average thermal expansion coefficient (CTE) of the core layer 核心 In some examples, the average coefficient of thermal expansion (CTE) of the first and second coating layers is 包覆 ) is higher than the average thermal expansion coefficient (CTE) of the core layer 核心 ).

[0059] Figure 2 The process of processing fused-drawn laminated glass according to some embodiments is described. The slope change of the glass index (inset) represents the gradient index effect on the surface, which results in minimization of Fresnel reflections on the surface. The initial fused-drawn glass laminate is equivalent to the above-mentioned Figure 1 The structure described in the embodiment of the present invention has at least one amorphous cladding layer (one or two) and an amorphous core layer. After the first heat treatment step, the cladding layers 104a and 104b are phase-separated into cladding layers 104c and 104d, while the core layer 102 remains amorphous.

[0060] Step 1 - Heat Treatment

[0061] Heat treatment can be performed in a Thermo Scientific Furnace (PDL), starting from room temperature and increasing to a predetermined temperature. The sample is heated for 1 to 60 minutes (e.g., 20 minutes) and then quenched on a cooling stage. In some instances, phase separation can also be induced by heat, electron beam, laser, or a combination thereof.

[0062] In some examples, the heat treatment can be carried out at a temperature in the range of 400°C to 1300°C, or 450°C to 1250°C, or 500°C to 1200°C, or 550°C to 1150°C, or 600°C to 1100°C, or 650°C to 1050°C, or 700°C to 1000°C, or 400°C to 700°C, or 450°C to 650°C, or 1000°C to 1200°C, or 1050°C to 1150°C, or 725°C to 975°C, or 750°C to 950°C, or 775°C to 925°C, or 800°C to 900°C, or 700°C to 850°C, or 850°C to 1000°C, or any intermediate value or range disclosed therein. In some examples, the heat treatment may be performed at a temperature of 400°C, or 425°C, or 450°C, or 475°C, or 500°C, or 525°C, or 550°C, or 575°C, or 600°C, or 625°C, or 650°C, or 675°C, or 700°C, or 725°C, or 750°C, or 775°C, or 800°C, or 825°C, or 850°C. , or 875°C, or 900°C, or 925°C, or 950°C, or 975°C, or 1000°C, or 1025°C, or 1050°C, or 1075°C, or 1100°C, or 1125°C, or 1150°C, or 1175°C, or 1200°C, or 1225°C, or 1250°C, or 1275°C, or 1300°C, or any intermediate value disclosed therein.

[0063] In some examples, the heat treatment can be performed for a time in the range of 1 min to 200 hr, 0.1 hr to 100 hr, or 0.5 hr to 75 hr, or 1 hr to 50 hr, or 2 hr to 40 hr, or 4 hr to 35 hr, or 6 hr to 30 hr, or 8 hr to 25 hr, or 10 hr to 25 hr, or 4 hr to 64 hr, or 8 hr to 32 hr, or 4 hr to 32 hr, or 4 hr to 16 hr, or 8 hr to 64 hr, or 16 hr to 64 hr, or 32 hr to 64 hr, or any intermediate value or range disclosed therein. In some examples, the heat treatment can be performed for 1 min, 0.1 hr, or 0.5 hr, or 1 hr, or 2 hr, or 4 hr, or 6 hr, or 8 hr, or 10 hr, or 12 hr, or 14 hr, or 16 hr, or 20 hr, or 24 hr, or 28 hr, or 32 hr, or 36 hr, or 40 hr, or 44 hr, or 48 hr, or 52 hr, or 56 hr, or 60 hr, or 64 hr, or 72 hr, or 80 hr, or 88 hr, or 96 hr, or 100 hr, or 120 hr, or 140 hr, or 160 hr, or 180 hr, or 200 hr, or any intermediate value disclosed therein.

[0064] In some examples, any temperature or temperature range is selected independently of any time or time range. For example, the heat treatment can be performed at 700°C for 64 hours, 750°C for 32 hours, 800°C for 16 hours, 850°C for 8 hours, 900°C for 4 hours, etc.

[0065] In the second etching process step, the phase-separated cladding layers 104c and 104d and the core layer 102 are subjected to liquid or vapor etching.

[0066] Step 2 - Etching

[0067] The etching process can be performed as follows. A two volume percent (2 vol.%) hydrogen fluoride (HF) solution is prepared. The sample is taped on one side for single-sided etching. Some samples are etched in a certain volume of HF solution for different times (e.g., 30 seconds), then rinsed with deionized (DI) water and dried with compressed nitrogen.

[0068] In some examples, wet chemical etching is performed using a suitable component capable of degrading or dissolving the glass article. For example, suitable wet etching chemicals include acids (e.g., HCl, HNO3, H2SO4, H3PO4, H3BO3, HBr, HClO4, HF, acetic acid, citric acid, NH4F, acidic ammonium fluoride), bases (e.g., LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2), H2O, or combinations thereof. In some examples, the wet chemical etchant has a concentration in the range of 0.1 vol.% to 10 vol.%, or 0.2 vol.% to 9 vol.%, or 0.3 vol.% to 8 vol.%, or 0.4 vol.% to 7 vol.%, or 0.5 vol.% to 6 vol.%, or 0.6 vol.% to 5 vol.%, or 0.25 vol.% to 5 vol.%, or 0.25 vol.% to 3 vol.%, or 0.25 vol.% to 2 vol.%, or intermediate values or ranges disclosed therein.

[0069] In some examples, the wet chemical etchant has a concentration of 0.1 vol.%, or 0.15 vol.%, or 0.2 vol.%, or 0.25 vol.%, or 0.3 vol.%, or 0.35 vol.%, or 0.4 vol.%, or 0.45 vol.%, or 0.5 vol.%, or 0.55 vol.%, or 0.6 vol.%, or 0.65 vol.%, or 0.7 vol.%, or 0.75 vol.%, or 0.8 vol.%, or 0.85 vol.%, or 0.9 vol.%, or 0.95 vol.%, or 1 vol.%, Or 1.1vol.%, or 1.2vol.%, or 1.3vol.%, or 1.4vol.%, or 1.5vol.%, or 1.6vol.%, or 1.7vol.%, or 1.8vol.%, or 1.9vol.%, or 2vol.%, or 2.25vol.%, or 2.5vol.%, or 3vol.%, or 3.5vol.%, or 4vol.%, or 4.5vol.%, or 5vol.%, or 6vol.%, or 7vol.%, or 8vol.%, or 9vol.%, or 10vol.%, or any intermediate value disclosed therein.

[0070] In some examples, at least one of the following dry etching processes is performed: ion beam etching, plasma etching, reactive ion etching, or a combination thereof, using a suitable gas such as oxygen-containing gas, nitrogen-containing gas, halogen-containing gas, or fluorine-containing gas, or a combination thereof.

[0071] In some examples, the etching process can be performed for a time in the range of 1 sec to 24 hr, 5 sec to 20 hr, 10 sec to 16 hr, 20 sec to 12 hr, 30 sec to 8 hr, 45 sec to 4 hr, or any intermediate value or range disclosed therein. In some examples, the etching process can be performed for a time in the range of 1 sec to 300 sec, or 5 sec to 250 sec, or 10 sec to 200 sec, or 20 sec to 150 sec, or 10 sec to 120 sec, or 20 sec to 120 sec, or 30 sec to 120 sec, or 45 sec to 120 sec, or 60 sec to 120 sec, or 90 sec to 120 sec, or any intermediate value or range disclosed therein. In some examples, the etching process may be performed for 1 sec, or 5 sec, or 10 sec, or 20 sec, or 30 sec, or 45 sec, or 60 sec, or 75 sec, or 90 sec, or 105 sec, or 120 sec, or 150 sec, or 180 sec, or 210 sec, or 240 sec, or 270 sec, or 300 sec, 4 hr, or 8 hr, or 12 hr, or 16 hr, or 20 hr, or 24 hr, or any intermediate value disclosed therein.

[0072] In some examples, the selection of any etchant is independent of any time or time range and concentration or concentration range. For example, the etching process can be performed as a wet chemical etch using 0.5 vol.% HF or the like.

[0073] Therefore, in step 2 after phase separation, the glass sample is etched to form a porous surface structure with a channel width determined by the size of the silica-poor phase region and the heat treatment conditions. In other words, by removing boron or other elements near the coating glass / air interface, the etching process produces a graded glass index greater than 5 nm (e.g., 50 nm), or on the order of 1 nm to 100 nm, or 100 nm to 1 μm, or 1 μm to 5 μm.

[0074] By the etching process described herein, the boron-rich phase is removed. Thus, as long as the phase separation produces two phases, one of which etches at a preferentially higher or lower rate, the etching process can preferentially target specific elements of the coating composition. However, the preferential etching depends on the glass. For example, in borosilicate glasses, the boron matrix is generally etched faster than the silicate matrix. In other systems that do not contain boron (e.g., aluminosilicate glasses), specific phase separation occurs due to their unique chemical properties.

[0075] Figure 3A and Figure 3B The incident light is transmitted through the Figure 2 Before treatment ( Figure 3A ) and after treatment ( Figure 3B ) cover glass. Approximately 8% of the incident light is reflected by Fresnel at the cover glass / air interface due to the change in refractive index of the two media. For an observer of a display experiencing the Fresnel effect, the reduced light transmittance from the display can adversely affect the viewing experience. This is further complicated by the presence of ambient light outside the display that interferes with the transmitted light (i.e., "glare"). Figure 3A The schematic diagram illustrates the reduced visibility of a display due to lower transmittance of incident light and increased glare.

[0076] Figure 3B The optical behavior of the phase-separated glass after the heat treatment in step 1 and the etching treatment in step 2 is shown. The incident light from the display can pass (i.e., be transmitted) with negligible reflection (i.e., minimized Fresnel reflection). Figure 2 By adjusting the grain size of the glass (104c and 104d), optical properties such as reduced glare or increased haze and clarity can be optimized for the viewer viewing the display and depending on the application. In some examples, the phase-separated glass produced by a specific cladding glass composition and heat treatment conditions can have a grain size within the following ranges: 1 nm to 10 μm, or 10 nm to 1 μm, or 100 nm to 500 nm, or any intermediate values or ranges disclosed therein.

[0077] As explained above and Figure 3B As shown in , for display applications, ambient light reflected at the cover glass / air interface is reflected back toward the viewer, causing glare. After processing in step 2, and at least in part due to the grain size of the phase-separated cover glass layer, the ambient light is able to primarily pass through the glass, and back reflections caused by reflections from internal display components are scattered to some extent in the phase-separated system, reducing glare.

[0078] Example

[0079] Example 1 - Confirmation of Phase Separation

[0080] Figures 4A-4F Illustrate images of the coated portion of the laminate after heat treatment at different times and temperatures (after step 1 above) according to some embodiments. The heat treatment tested was 64 hours at 700°C ( Figure 4B ), 750℃ for 32hr( Figure 4C ), 800℃ for 16hr( Figure 4D ), 850℃ for 8 hours ( Figure 4E ) and 900℃ for 4hr( Figure 4F ). No control samples ( Figure 4A ) for heat treatment.

[0081] As the temperature increases from 700°C to 900°C, the difference in the separated glass phases increases, as indicated by the opalescent halo caused by light scattering. The degree of phase separation increases with increasing temperature, as evident by the larger "grain" size. As the length scales of the two phases increase, this leads to optical scattering and produces an opaque glass, known as the opalescent / halo effect. Therefore, it is desirable to minimize the degree of phase separation to ensure that the glass sample remains transparent.

[0082] Figures 5A-5E SEM images of phase separation in the cladding portion of a laminate after heat treatment at different times and temperatures (after step 1 above) according to some embodiments are illustrated. Scanning electron microscope (SEM) images were obtained using a scanning electron microscope (Zeiss Gemini 500). The samples were heat treated for 1 hour to explore the effect of temperature on phase separation in the glass composition. It was found that phase separation much smaller than the wavelength of light (e.g., <100 nm) can provide the optical benefits we observed.

[0083] based on Figures 4A to 5E Based on the data, it can be determined that in some examples, the optimal temperature and time for the heat treatment (step 1) is 800°C for 20 minutes.

[0084] Example 2—Characterization

[0085] Transmittance (%) and transmission haze measurements were performed using a Ci7860 X-Rite spectrophotometer (at an incident light angle of 8°) using at least one of the following standards: CIE No 15, ASTM D1003, ISO 7724 / 1. DOI and gloss measurements were performed using a Rhopoint IQ glossmeter using at least one of the following standards: ASTM E430 (for DOI) and ISO 2813, ISO 7668, ASTM D523, ASTM D2457, DIN 67530, JIS 8741, JIS K 5600-4-7 for gloss (measured at angles of 20°, 60°, and 85°).

[0086] Figures 6A-6DThe optical property measurements of the laminate as a function of the temperature conditions during the fusion drawn laminate (drawn glass), heat treatment step, and etching step according to some embodiments are described. Broadly speaking, to determine whether a glass surface has anti-reflection or anti-glare capabilities, the % transmittance should increase from the drawn glass to the etching step, while the gloss and DOI should decrease. Figure 6A and Figure 6C As shown, heat treatment at 700°C for 64 hours resulted in the most significant increase in % transmittance (-92% (or 8% reflectance) to -96% transmittance (or 4% reflectance)) and decrease in gloss (arbitrary gloss units). A decrease in DOI was also observed with heat treatment at 700°C for 64 hours. At temperatures above 700°C, no visible increase in % transmittance (e.g., at 750°C and 800°C) or a substantial decrease in % transmittance (e.g., at 850°C and 900°C) was observed, even though both gloss and DOI were substantially reduced. As shown in FIG. Figure 6D As shown in , the haze value tested at 700°C to 900°C is less than 2%.

[0087] To further verify the observed measurement results, Figure 7 The total transmittance (%) of the control sample and a plurality of (21) test samples are shown, wherein the test samples were heat-treated at 700°C for 64 hours (for samples A-1 to A-12 and B-1 to B5) or at 800°C for 20 minutes (for samples C-1 to C-4), followed by an etching process with 0.5 vol.% HF for 30 seconds (for samples A-1 to A-12) or an etching process with 2.0 vol.% HF for 30 seconds (for samples B-1 to B-5 and C-1 to C-4). In general, the total transmittance of samples A-1 to A-12 is close to 94%, while the total transmittance of samples B-1 to B-5 and C-1 to C-4 is close to 99%. The total transmittance of all samples is much higher than that of the control sample (~91.5%).

[0088] Figures 8A-8D The total transmittance (%) and distinctness of image (DOI) as a function of etching time and acid concentration according to some embodiments are illustrated. In other words, to determine whether the etching conditions affect the optical properties (e.g., transmittance%) of the native glass, (i) the etching time was varied for a 0.5 vol.% HF acid concentration etchant, and (ii) the acid concentration was varied for an etching time of 30 seconds.

[0089] from Figure 8A and Figure 8B It can be seen that no matter the specific etching time (such as Figure 8A medium) or a specific acid concentration (e.g. Figure 8B) regardless of the performance of the etching process in step 2, it is likely that the transmittance will be higher than that of the control sample. For example, the transmittance improvement is in the range of 0.5% (etching time of 10-20 sec) to about 6% (etching time of 90 sec). Figure 8B It can be seen that the improvement in transmittance is in the range of 0.5% (0.25 vol.% HF) to about 7% (about 1.50 vol.% or more HF). For DOI, most etching times and acid concentrations may result in a lower DOI than the control sample. For example, all etching times ( Figure 8C ) and most HF concentrations ( Figure 8D ) are reduced. Based on Figures 8A to 8D Based on the data, it can be determined that in some examples, the optimal concentration and time for the etching process (step 2) is 2 vol.% for 30 sec to minimize time and cost.

[0090] These results show that by controlling (a) the heat treatment temperature and time, and (ii) the etching time and acid concentration, transmittance greater than 98% and DOI less than 30% can be achieved. The ability to tune the process parameters enables the solution to be scaled for mass production levels.

[0091] Example 3 - Phase Separated Coating and Core Layers

[0092] In some instances, both the cladding and core layers can undergo phase separation as a result of the heat treatment in step 1. In this case, the grain sizes of the cladding and core glass layers can be the same or different, depending on the desired optical properties for the end application. For example, after step 2, the cladding layer can contain a smaller grain size than the core layer to achieve a graded antireflection index while maintaining or enhancing the scratch-resistant surface. A core layer with a longer path length can be used to control glare or haze.

[0093] Thus, as described herein, the present disclosure relates to improved anti-reflective (AR) and anti-glare (AG) glass laminates having enhanced optical performance in display applications. Advantages of the resulting AR / AG glass laminates include: (1) the ability to achieve both anti-reflective and anti-glare behavior; (2) the use of a single layer of material as a broadband filter, effectively reducing reflections across the entire visible spectrum; (3) the provision of an environmentally friendly, highly durable, scratch-resistant glass-based solution; (4) strength without any additional IOX processing due to the mismatch in coefficient of thermal expansion (CTE) between the core and cladding layers of the laminate; (5) thermoforming to allow for various 3D shapes with uniform optical coatings; and (6) optimization of haze, glare, clarity, and transmittance depending on the end use of the application.

[0094] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the claimed subject matter.Accordingly, the claimed subject matter is not to be restricted except in light of the appended claims and their equivalents.

Claims

1. A method of forming a glass laminate, comprising: providing a substrate having a core layer and first and second cladding layers, wherein a surface of the core layer is directly adjacent to the cladding layers; heat-treating the substrate at a temperature such that the first and second cladding layers are phase-separated after the heat treatment, wherein the phase-separated first and second cladding layers have a grain size in a range of 10 nm to 1 μm; and The substrate is etched for at least 10 seconds, wherein The thickness of the first and second coating layers are each independently 50 μm to 1000 μm. The method of claim 1 , wherein the substrate is formed by a fusion lamination process.

3. The method according to claim 1 or claim 2, wherein before the heat treatment, the core layer is an amorphous core layer and the first and second cladding layers are amorphous cladding layers.

4. The method according to claim 1 or claim 2, wherein the heat treatment is performed at a temperature in the range of 400°C to 1300°C.

5. The method according to claim 1 or claim 2, wherein the heat treatment is carried out for a time in the range of 1 min to 200 hr.

6. The method according to claim 5, wherein the heat treatment is performed for a time ranging from 4 hr to 64 hr.

7. The method according to claim 1 or claim 2, wherein the etching process is carried out for a time in the range of 10 sec to 24 hr.

8. The method according to claim 1 or claim 2, wherein the etching is performed using a wet chemical etchant selected from at least one of the following: HCl, HNO3, H2SO4, H3PO4, H3BO3, HBr, HClO4, HF, acetic acid, citric acid, NH4F, acidic ammonium fluoride, LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2.

9. The method of claim 8, wherein the etchant is present in a concentration of at least 0.1 vol. % of the total solution volume.

10. The method of claim 8, wherein the etchant is present in a concentration ranging from 0.25 vol.% to 5 vol.% of the total solution volume.

11. The method according to claim 1 or claim 2, wherein the etching is performed using a dry etching process selected from at least one of the following: ion beam etching, plasma etching, reactive ion etching.

12. The method of claim 1 or claim 2, wherein the first and second cladding layers and the core layer are phase separated after the heat treatment. 13 . The method of claim 12 , wherein the phase-separated first and second cladding layers have a grain size smaller than a grain size of the phase-separated core layer.

14. A phase-separated glass laminate comprising: a substrate having a core layer and first and second phase-separated cladding layers, wherein a surface of the core layer is directly adjacent to the cladding layers, wherein the glass laminate has a transmittance of at least 96%, wherein the thickness of the first and second coating layers are each independently 50 μm to 1000 μm, and The first and second cladding layers comprise a grain size ranging from 10 nm to 1 μm.

15. The glass laminate of claim 14, wherein the core layer is a phase separated core layer.

16. The glass laminate of claim 15, wherein the first and second phase-separated cladding layers have a grain size smaller than a grain size of the phase-separated core layer.

17. The glass laminate of any one of claims 14-16, wherein the glass laminate has a % transmission of at least 98% and a clarity of image of less than 30%.

18. The glass laminate according to any one of claims 14 to 16, wherein the average coefficient of thermal expansion (CTE) of the first and second cladding layers is 包覆 ) is different from the average thermal expansion coefficient (CTE) of the core layer 核心 ).

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