Compositions and methods for producing glass-ceramic articles - Patents.com

Abstract

The light diffuser may include an amorphous phase and a crystalline phase including lithium disilicate and one or more of beta-spodumene or beta-quartz having a median particle size ranging from about 500 nanometers to about 1,000 nanometers. The crystalline phase may be dispersed throughout the volume of the light diffuser. The light diffuser may include, expressed in mole percent on an oxide basis, 60-75 mole percent SiO2, 2-9 mole percent Al2O3, 17-25 mole percent Li2O, and 0.5-6 mole percent Na2O+K2O. A method for manufacturing the light diffuser may include forming a mixture by melting together 60-75 mole percent SiO2, 2-9 mole percent Al2O3, 17-25 mole percent Li2O, and 0.5-6 mole percent Na2O+K2O, expressed in mole percent on an oxide basis. The method may include forming a ribbon from the mixture. The method may include heating the ribbon to about 850° C. to about 900° C. for about 0.5 hours to about 6 hours.

Description

Priority

[0001] This application claims priority under 35 U.S.C. §119(e) from U.S. Provisional Patent Application No. 63 / 017326, filed April 29, 2020, which is incorporated herein by reference in its entirety. [Technical Field]

[0002] The present disclosure relates generally to compositions and methods for making glass-ceramic articles, and more particularly to compositions and methods for making glass-ceramic articles, including lithium aluminum silica glass-ceramic articles. [Background technology]

[0003] Display devices include liquid crystal displays (LCDs), electrophoretic displays (EPDs), organic light emitting diode (OLED) displays, plasma display panels (PDPs), etc. The display device can be part of a portable electronic device, such as a consumer electronics appliance, a smartphone, a tablet, a wearable device, or a laptop computer.

[0004] Display devices often include illumination sources, such as light-emitting diodes (LEDs). LEDs can produce very bright point sources that, when viewed directly, can appear too intense and uncomfortable and / or can cause glare. For example, it is known to include diffusers in display devices to hide optical imperfections and / or improve brightness uniformity from the illumination source. Summary of the Invention [Problem to be solved by the invention]

[0005] It is known to fabricate diffusers from polymeric materials such as polycarbonate, polystyrene, and / or poly(methyl) methacrylate, however, polymeric materials may yellow over time, may have poor thermal stability, and / or may have poor dimensional stability.

[0006] As a result, there is a need to develop materials that can be used as diffusers that have high transparency, high haze, and good hiding power. Additionally, there is a need to develop such materials that have good thermal and / or dimensional stability and do not yellow over time. [Means for solving the problem]

[0007] Described herein are compositions and methods for producing glass-ceramic articles. The compositions of the present disclosure can simultaneously provide high light transmittance (e.g., about 40% or greater, about 40% to about 70%) and high haze (e.g., about 95% or greater, about 100% to about 105%). Providing a glass-ceramic article with high light transmittance and high haze can, for example, function as a diffuser, increasing brightness uniformity while efficiently transmitting light. Efficient light transmission can increase illumination from a display device and reduce the amount of energy lost from the illumination source as heat, thereby further increasing the stability of the display device.

[0008] Compositions according to embodiments of the present disclosure can be used to produce glass-ceramic articles containing lithium disilicate crystals. By providing the lithium disilicate crystals, the mechanical stability and strength of the glass-ceramic article can be enhanced. By substantially interlocking the lithium disilicate crystals, the mechanical stability and strength of the glass-ceramic article can be further enhanced.

[0009] The compositions of the present disclosure can be used to produce glass-ceramic articles further comprising one or more of β-spodumene or β-quartz. Without intending to be bound by theory, the β-spodumene or β-quartz crystals can increase the light scattering of the glass-ceramic article, thereby increasing the haze and hiding power of the glass-ceramic article. Furthermore, providing a median particle size ranging from about 500 nanometers to about 1,000 nanometers (e.g., from about 600 nanometers to about 800 nanometers) can increase the scattering of visible light (e.g., from about 380 nanometers to about 740 nanometers, from about 400 nanometers to about 700 nanometers), thereby increasing the haze and hiding power of the glass-ceramic article with respect to visible light.

[0010] Providing glass-ceramic articles made from alkali-containing aluminosilicate and / or alkali-containing aluminoborosilicate compositions can promote the formation of lithium disilicate, β-spodumene, and / or β-quartz crystals, which may be in solid solution. The alkali-containing aluminosilicate and / or alkali-containing aluminoborosilicate compositions can provide good thermal and / or dimensional stability. Furthermore, compositions containing a high mole percent (mol%) of lithium (e.g., about 17% or more, about 20% to about 25%) and low aluminum (e.g., about 10% or less, about 3% to about 9%) on an oxide basis can promote the formation of the above crystals. Providing compositions containing phosphorus (e.g., about 1 mol% to about 2 mol% on an oxide basis) can promote the nucleation of such crystals.

[0011] Heating compositions of embodiments of the present disclosure to a crystallization temperature ranging from about 850°C to about 900°C can promote crystal formation and controlled crystal growth. Additionally, heating the composition to a nucleation temperature ranging from about 550°C to about 800°C before heating the composition to the crystallization temperature can increase the density of crystals and / or improve control over crystal growth. Providing compositions with a liquidus viscosity of about 80 Pascal-seconds or greater and / or a liquidus temperature of about 1000°C or greater can facilitate processing of glass-ceramic articles and their precursors.

[0012] Several exemplary embodiments of the present disclosure are described below, with the understanding that any of the features of the various embodiments may be used alone or in combination with each other.

[0013] In some embodiments, the light diffuser can include an amorphous phase and a crystalline phase. The crystalline phase can include lithium disilicate and one or more of beta-spodumene or beta-quartz having a median particle size ranging from about 500 nanometers to about 1,000 nanometers. The crystalline phase can be dispersed throughout the volume of the light diffuser. The light diffuser can include, expressed in mole percent on an oxide basis, 60-75 mole percent SiO2, 2-9 mole percent Al2O3, 17-25 mole percent Li2O, and 0.5-6 mole percent Na2O+K2O.

[0014] In further embodiments, the light diffuser may further comprise, expressed in mole percent on an oxide basis, 0.5-2 mole percent P2O5, 0.2-8 mole percent ZrO2, 0-5 mole percent B2O3, 0-5 mole percent MgO+CaO+SrO, 0-2 mole percent ZnO, and 0-2 mole percent SnO2.

[0015] In still further embodiments, the light diffuser may include, expressed in mole percent on an oxide basis, 67-70 mole percent SiO2, 2.5-4.5 mole percent Al2O3, 21-24 mole percent Li2O, 0.5-2 mole percent Na2O, 0-1 mole percent K2O, 1-2 mole percent P2O5, 1.5-4 mole percent ZrO2, and 0.1 mole percent SnO2.

[0016] In further embodiments, β-spodumene may predominate.

[0017] In further embodiments, beta-quartz may be predominant.

[0018] In further embodiments, the median particle size can range from about 600 nanometers to about 800 nanometers.

[0019] In a further embodiment, the lithium disilicate crystals may be substantially interlocked.

[0020] In further embodiments, the light diffuser can further have a first major surface and a second major surface opposite the first major surface, and a thickness defined between the first and second major surfaces can range from about 0.5 millimeters to about 5 millimeters.

[0021] In still further embodiments, the thickness of the light diffuser can range from about 0.8 millimeters to about 1.5 millimeters.

[0022] In still further embodiments, the light diffuser can have a light transmittance ranging from about 40% to about 70%.

[0023] In still further embodiments, the light transmittance of the light diffuser can range from about 50% to about 60%.

[0024] In still further embodiments, the light diffuser can have a haze of about 95% or greater.

[0025] In still further embodiments, the haze of the light diffuser can range from about 100% to about 105%.

[0026] In still further embodiments, the light diffuser can have an integrated light transmittance of about 40% or greater.

[0027] In still further embodiments, the integrated light transmittance of the light diffuser can range from about 50% to about 70%.

[0028] In still further embodiments, the light diffuser can have a hiding power of about 20 millimeters or less.

[0029] In still further embodiments, the hiding power of the light diffuser can range from about 1 millimeter to about 10 millimeters.

[0030] In still further embodiments, the light diffuser can have a color shift of about 0.2 or less.

[0031] In still further embodiments, the color shift of the light diffuser can range from about -0.1 to about 0.1.

[0032] In further embodiments, the display device may include a light source. The display device may include a light diffuser. The display device may include an image display device having a plurality of pixels. The light diffuser may be positioned between the light source and the image display device.

[0033] In some embodiments, a method for fabricating a light diffuser can include forming a mixture by melting together 60-75 mol% SiO, 2-9 mol% AlO, 17-25 mol% LiO, and 0.5-6 mol% NaO+KO, expressed on an oxide basis. The method can include forming a ribbon from the mixture. The ribbon can have a first major surface and a second major surface opposite the first major surface. The method can include heating the ribbon to a crystallization temperature ranging from about 850°C to about 900°C for a crystallization time ranging from about 0.5 hours to about 6 hours, where heating the ribbon to the crystallization temperature results in the formation of a crystalline phase including lithium disilicate and one or more of β-spodumene or β-quartz having a median particle size ranging from about 500 nanometers to about 1,000 nanometers. The crystalline phase can be dispersed throughout the volume of the light diffuser.

[0034] In further embodiments, the method may further include heating the ribbon to a nucleation temperature ranging from about 550°C to about 800°C for a nucleation time ranging from about 0.5 hours to about 6 hours before heating the ribbon to the crystallization temperature.

[0035] In further embodiments, forming the ribbon may include rolling, slot drawing, or float drawing the mixture.

[0036] In further embodiments, the mixture may have a liquidus temperature ranging from about 1000°C to about 1250°C.

[0037] In further embodiments, the mixture may have a liquidus viscosity ranging from about 800 Pascal·seconds (Pa·s) to about 1,000 Pa·s.

[0038] In still further embodiments, the liquidus viscosity may range from about 140 Pa·s to about 600 Pa·s.

[0039] In further embodiments, the mixture may further comprise, expressed in mole percent on an oxide basis, 0.5-2 mole percent P2O5, 0.2-8 mole percent ZrO2, 0-5 mole percent B2O3, 0-5 mole percent MgO+CaO+SrO, 0-2 mole percent ZnO, and 0-2 mole percent SnO2.

[0040] In still further embodiments, the mixture can include, expressed in mole percent on an oxide basis, 67-70 mole percent SiO2, 2.5-4.5 mole percent Al2O3, 21-24 mole percent Li2O, 0.5-2 mole percent Na2O, 0-1 mole percent K2O, 1-2 mole percent P2O5, 1.5-4 mole percent ZrO2, and 0.1 mole percent SnO2.

[0041] In further embodiments, β-spodumene may predominate.

[0042] In further embodiments, beta-quartz may be predominant.

[0043] In further embodiments, the median particle size can range from about 600 nanometers to about 800 nanometers.

[0044] In a further embodiment, the lithium disilicate crystals may be substantially interlocked.

[0045] In further embodiments, the light diffuser can have a light transmittance ranging from about 40% to about 70%.

[0046] In further embodiments, the light diffuser can have a haze of about 95% or greater.

[0047] In further embodiments, the light diffuser can have an integrated light transmittance of about 40% or greater.

[0048] In further embodiments, the light diffuser can have a hiding power of about 20 millimeters or less.

[0049] In further embodiments, the light diffuser can have a color shift of about 0.2 or less. [Brief explanation of the drawings]

[0050] These and other features and advantages of embodiments of the present disclosure will be better understood from the following detailed description when taken in conjunction with the accompanying drawings. [Figure 1] 1A and 1B are diagrams illustrating exemplary embodiments of a light diffuser and a display device according to embodiments of the present disclosure. [Figure 2] 1, showing a schematic diagram of a scanning electron microscope (SEM) image of some embodiments of the present disclosure. [Figure 3] 1, showing a schematic diagram of a scanning electron microscope (SEM) image of some embodiments of the present disclosure. [Figure 4] Schematic illustration of an X-ray diffraction (XRD) image of some embodiments of the present disclosure. [Figure 5] Schematic representation of cumulative grain size for some embodiments of the present disclosure. [Figure 6]FIG. 1 is an illustration of a hiding power test apparatus according to some embodiments of the present disclosure. [Figure 7] Flowchart illustrating an exemplary method of an embodiment of the present disclosure. Throughout this disclosure, drawings are used to highlight certain aspects. Therefore, the relative sizes of different regions, parts, and substrates shown in the drawings should not be considered proportional to their actual relative sizes unless otherwise specified. DETAILED DESCRIPTION OF THE INVENTION

[0051] Embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. However, the claims can encompass many different aspects of various embodiments and should not be considered limited to the embodiments set forth herein.

[0052] Unless otherwise specified, a discussion of a feature of some embodiments may be equally applicable to any corresponding feature of any of the embodiments of the present disclosure. For example, the use of identical part numbers throughout the present disclosure may indicate that, in some embodiments, the identified features are identical to one another, and that a discussion of a identified feature of one embodiment may be equally applicable to the identified feature of any of the other embodiments of the present disclosure, unless otherwise specified.

[0053] As used herein, "glass-ceramic" includes one or more crystalline phases and an amorphous, residual glass phase. Amorphous materials and glass-ceramics may be strengthened. As used herein, the term "strengthened" may refer to materials that have been chemically strengthened, for example, by ion-exchanging smaller ions with larger ions within the surface of the substrate, as described below. However, other strengthening methods known in the art, such as thermal strengthening or using a mismatch in thermal expansion coefficients between portions of the substrate to create regions of compressive stress and a central tension region, may also be used to form a strengthened substrate.

[0054] "Glass-ceramic" includes materials produced by controlled crystallization of glass. In some embodiments, glass-ceramics have a crystallinity of about 1% to about 99%. Suitable glass-ceramic embodiments of the present disclosure may include Li2O·Al2O3·SiO2-based (i.e., LAS-based) glass-ceramics and / or glass-ceramics having a predominant crystalline phase including β-quartz solid solution, β-spodumene, cordierite, petalite, and / or lithium disilicate. In some embodiments, glass-ceramic materials can be formed by heating a glass-based material to form a ceramic (e.g., crystalline) portion. In further embodiments, glass-ceramic materials may include one or more nucleating agents that can promote the formation of a crystalline phase.

[0055] As used herein, "oxide basis" means that a component is measured as if the non-oxygen component in the compound had been converted to the specified oxide form, or, if no specific oxide form is specified, to the fully oxidized oxide. For example, sodium (Na) on an oxide basis refers to the amount relative to sodium oxide (NaO), while silicon, silica, and silicates on an oxide basis refer to the amount relative to silicon dioxide (SiO). Thus, a component need not actually be in a specific oxide form or a fully oxidized oxide form for the component to be counted in an "oxide basis" amount. As used herein, mole percent (mol%) refers to the percentage of total moles in a mixture, composition, or glass-ceramic article that includes the specified component. Therefore, measuring "mole percent (mol%) on an oxide basis" for a specified component involves conceptually converting the material containing the non-oxygen element of the specified component to the specified oxide form, or, if no specific oxide form is specified, to the fully oxidized oxide, before calculating the percentage of total moles on an oxide basis in the mixture, composition, or glass-ceramic article. As used herein, component amounts expressed in mole percent on an oxide basis are equally applicable to mixtures, compositions, and glass-ceramic articles that can be used, for example, as light diffusers. Thus, when a light diffuser is described herein as including an amorphous phase and / or a crystalline phase and a mole percent (or mole percent range) of an oxide (e.g., "on an oxide basis") is recited, such mole percent (or mole percent range) refers to the total relative molar contribution of that oxide (e.g., as an initial formulation component or an initial formulation component that can be converted to a particular oxide) to all of the amorphous and / or crystalline species in the light diffuser.

[0056] Glass-ceramics according to embodiments of the present disclosure are made from alkali-containing aluminosilicate and / or alkali-containing aluminoborosilicate compositions. As used herein, R2O can refer to alkali metal oxides, such as Li2O, Na2O, K2O, Rb2O, and Cs2O. As used herein, R2O can refer to MgO, CaO, SrO, BaO, and ZnO. In some embodiments, the glass-based substrate may optionally further comprise Na2SO4, NaCl, NaF, NaBr, K2SO4, KCl, KF, KBr, As2O3, Sb2O3, SnO2, Fe2O3, MnO, MnO2, MnO3, Mn2O3, Mn3O4, and Mn2O7 in the range of 0 mol% to about 2 mol%. In some embodiments, the glass-ceramic material may include one or more oxides, nitrides, oxynitrides, carbides, borides, silicates, and / or silicides. Exemplary embodiments of oxides include silica (SiO), zirconia (MgO), titania (TiO), hafnium oxide (HfO), yttrium oxide (YO), iron oxide, beryllium oxide, vanadium oxide (VO), fused quartz, mullite (a mineral containing a combination of aluminum oxide and silicon dioxide), and spinel (Mg (ZrO2), zircon (ZrSiO4), alumina (Al2O3), alkali metal oxides (e.g., potassium oxide (KO), sodium oxide (Na2O), lithium oxide (Li2O)), alkaline earth metal oxides (e.g., magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO)), titania (TiO2), zinc oxide (ZnO), tin oxide (SnO2), phosphorus pentoxide (PO5), boron oxide (BO3), hafnium oxide (HfO2), yttrium oxide (YO3), iron oxide, beryllium oxide, vanadium oxide (VO2), fused quartz, mullite (a mineral containing a combination of aluminum oxide and silicon dioxide), and spinel (MgAl2O4). Exemplary embodiments of ceramic nitrides include silicon nitride (Si3N4), aluminum nitride (AlN), gallium nitride (GaN), beryllium nitride (Be3N2), boron nitride (BN), tungsten nitride (WN), vanadium nitride, alkaline earth metal nitrides (e.g., magnesium nitride (Mg3N2)), nickel nitride, and tantalum nitride. Exemplary embodiments of oxynitrides include silicon oxynitride, aluminum oxynitride, and SiAlON (a combination of alumina and silicon nitride, having the chemical formula, e.g., Si 12-m-n Al m+n O n N 16-n , Si 6-n Al n O n N 8-n , or Si 2-n Al n O 1+n N 2-n(where m, n, and the resulting subscripts are all natural numbers). Exemplary embodiments of carbide and carbon glass-ceramics include silicon carbide (SiC), tungsten carbide (WC), iron carbide, boron carbide (B4C), alkali metal carbides (e.g., lithium carbide (Li4C3)), alkaline earth metal carbides (e.g., magnesium carbide (Mg2C3)), and graphite. Exemplary embodiments of borides include chromium boride (CrB2), molybdenum boride (Mo2B5), tungsten boride (W2B5), iron boride, titanium boride, zirconium boride (ZrB2), hafnium boride (HfB2), vanadium boride (VB2), niobium boride (NbB2), and lanthanum boride (LaB6). Exemplary embodiments of silicides include molybdenum disilicide (MoSi), tungsten disilicide (WSi), titanium disilicide (TiSi), nickel disilicide (NiSi), alkali metal silicides (e.g., sodium silicide (NaSi)), alkaline earth metal silicides (e.g., magnesium silicide (MgSi)), hafnium disilicide (HfSi), and platinum silicide (PtSi).

[0057] Embodiments of the present disclosure may include silica (SiO2), on an oxide basis. Silica may comprise the highest mole percent, on an oxide basis, in the mixture, composition, and / or glass-ceramic article. Silica may be part of both the glass phase and one or more crystalline phases. Without intending to be bound by theory, silica may be a component of lithium disilicate, β-spodumene, and β-quartz crystals. Thus, when a light diffuser is described herein as comprising an amorphous and / or crystalline phase and lists a mole percent (or mole percent range) of silica or a silicon-containing component convertible to silica (e.g., "on an oxide basis"), such mole percent (or mole percent range) refers to the total relative molar contribution of silica (e.g., as an initial formulation component) to all of the amorphous and / or crystalline species in the light diffuser. As a result, the silica content should be sufficiently high (e.g., about 60% or more mole percent, on an oxide basis) to allow for the formation of crystals and stabilization of the glass phase. Additionally, without intending to be bound by theory, increasing the silica content can decrease the liquidus viscosity of the resulting mixture, composition, and / or glass-ceramic article. As a result, the silica content may be limited (e.g., about 75% or less) to facilitate processing at an appropriate liquidus viscosity (e.g., about 80 Pascal-seconds or greater). In some embodiments, the amount of silica, in mole percent on an oxide basis, may be about 60% or greater, about 65% or greater, about 67% or greater, about 68% or greater, about 70% or greater, about 72% or greater, about 75% or less, about 72% or less, about 71% or less, about 70% or less, or about 68% or less. In some embodiments, the amount of silica in mole % on an oxide basis can range from about 60% to about 75%, about 65% to about 72%, about 65% to about 71%, about 65% to about 70%, about 67% to about 70%, about 68% to about 70%, about 60% to about 72%, about 65% to about 71%, about 67% to about 71%, about 68% to about 71%, about 65% to about 75%, about 68% to about 72%, about 70% to about 72%, about 71% to about 72%, or any range or sub-range therebetween.

[0058] Embodiments of the present disclosure may include alumina (Al2O3) on an oxide basis. Without intending to be bound by theory, alumina may be a component of β-spodumene crystals. Thus, when a light diffuser is described herein as including an amorphous phase and / or a crystalline phase and a mole percent (or mole percent range) of alumina or an aluminum-containing component that can be converted to alumina (e.g., "on an oxide basis") is listed, such mole percent (or mole percent range) refers to the total relative molar contribution of alumina (e.g., as an initial formulation component) to all of the amorphous and / or crystalline species in the light diffuser. However, the alumina content may be limited (e.g., about 7% or less on an oxide basis) to allow β-spodumene crystals to have particle sizes described below without growing too large and to substantially connect the lithium disilicate crystals. Additionally, increasing the alumina content may increase the liquidus viscosity of the mixture, composition, and / or glass-ceramic article. Limiting the alumina content enables processing by maintaining a liquidus viscosity of about 1,000 Pascal-seconds or less. In addition, increasing the alumina content can improve the mechanical properties of the resulting glass-ceramic article. In some embodiments, the amount of alumina, in mole percent on an oxide basis, can be about 2% or more, about 2.5% or more, about 3% or more, about 3.5% or more, about 4% or more, about 5% or more, about 9% or less, about 7% or less, about 6% or less, about 5% or less, about 4.5% or less, about 4% or less, about 3.5% or less, or about 3% or less. In some embodiments, the amount of alumina in mole % on an oxide basis can range from about 2% to 9%, about 2% to about 7%, about 2% to about 6%, about 2% to about 5%, about 2% to about 4%, about 2.5% to about 4.5%, about 2.5% to about 4%, about 2.5% to about 3.5%, about 2.5% to about 3%, about 2.5% to about 9%, about 2.5% to about 7%, about 2.5% to about 6%, about 2.5% to about 5%, about 3% to about 5%, about 3% to about 4.5%, about 3% to about 4%, about 3% to about 9%, about 3% to about 7%, about 3.5% to about 7%, about 3.5% to about 6%, about 3.5% to about 5%, about 3.5% to about 4.5%, or any range or sub-range therebetween.

[0059] Embodiments of the present disclosure may include lithium oxide (LiO) on an oxide basis. Without intending to be bound by theory, lithium oxide may be a component of β-spodumene crystals. Thus, when a light diffuser is described herein as including an amorphous and / or crystalline phase and a mole percent (or mole percent range) of lithium oxide or a lithium-containing component convertible to lithium oxide (e.g., "oxide basis") is listed, such mole percent (or mole percent range) refers to the total relative molar contribution of lithium oxide (e.g., as an initial formulation component) to all of the amorphous and / or crystalline species in the light diffuser. Providing a sufficient lithium oxide content (e.g., about 17% or more mole percent on an oxide basis) can allow β-spodumene to become the predominant crystalline phase in the resulting glass-ceramic article. Increasing the lithium oxide content can decrease the liquidus viscosity of the mixture, composition, and / or glass-ceramic article. However, the lithium oxide content can be limited (e.g., about 25% or less, by mole %, based on oxide) to facilitate processing of the composition (e.g., a liquidus viscosity of about 80 Pascal-seconds or greater) and to allow β-spodumene crystals to grow without becoming too large and have a particle size described below. In some embodiments, the amount of lithium oxide, by mole %, based on oxide, can be about 17% or more, about 19% or more, about 20% or more, about 21% or more, about 22% or more, about 25% or less, about 24% or less, about 23% or less, or about 22% or less. In some embodiments, the amount of lithium oxide, in mole % on an oxide basis, can range from about 17% to about 25%, about 17% to about 24%, about 17% to about 23%, about 19% to about 23%, about 20% to about 23%, about 21% to about 23%, about 22% to about 23%, about 19% to about 25%, about 21% to about 25%, about 21% to about 24%, about 22% to about 24%, or any range or sub-range therebetween.

[0060] Embodiments of the present disclosure may include alkali metal oxides other than Li2O, on an oxide basis. Generally, increasing the alkali metal oxide content can decrease the liquidus temperature of the mixture, composition, and / or glass-ceramic article. In some embodiments, the total amount of alkali metal oxides excluding Li2O, on an oxide basis, can be about 0.5% or more, about 1% or more, about 1.5% or more, about 2% or more, about 6% or less, about 4% or less, about 3% or less, about 2.5% or less, or about 2% or less. In some embodiments, the total amount of alkali metal oxides, excluding Li2O, in mole percent on an oxide basis, can range from about 0.5% to about 6%, about 0.5% to about 4%, about 0.5% to about 3%, about 0.5% to about 2.5%, about 1% to about 6%, about 1% to about 4%, about 1% to about 3%, about 1.5% to about 3%, about 1.5% to about 2.5%, about 1.5% to about 2%, about 2% to about 3%, or any range or sub-range therebetween.

[0061] In some embodiments, embodiments of the present disclosure may include alkali metal oxides, including sodium oxide (NaO) and / or potassium oxide (KO). Thus, when a light diffuser is described herein as including an amorphous and / or crystalline phase and a mole percent (or mole percent range) of sodium oxide or a sodium-containing component convertible to sodium oxide (e.g., "oxide basis") is listed, such mole percent (or mole percent range) refers to the total relative molar contribution of sodium oxide (e.g., as an initial formulation component) to all of the amorphous and / or crystalline species in the light diffuser. Increasing the sodium oxide and / or potassium oxide content can reduce the liquidus viscosity of the mixture, composition, and / or glass-ceramic article, thereby reducing damage to the composition during heat treatment processes, including nucleation and / or crystallization. Additionally, sodium oxide content can facilitate subsequent ion exchange (e.g., chemical strengthening) of the resulting glass-ceramic article. In further embodiments, the amount of sodium oxide, in mole % on an oxide basis, can be about 0.5% or more, about 1% or more, about 1.5% or more, about 6% or less, about 4% or less, about 2% or less, or about 1.5% or less. In some embodiments, the amount of sodium oxide, in mole % on an oxide basis, can range from about 0.5% to about 6%, about 0.5% to about 4%, about 0.5% to about 2%, about 0.5% to about 1.5%, about 1% to about 1.5%, about 1% to about 6%, about 1% to about 4%, about 1% to about 2%, about 1.5% to about 2%, or any range or sub-range therebetween. In further embodiments, the amount of potassium oxide, in mole % on an oxide basis, can be 0% or more, about 0.5% or more, about 5.5% or less, about 4% or less, about 2% or less, or about 1% or less. In further embodiments, the amount of potassium oxide, in mole % on an oxide basis, can range from 0% to about 5.5%, 0% to about 4%, 0% to about 2%, 0% to about 1%, about 0.5% to about 5.5%, about 0.5% to about 4%, about 0.5% to about 2%, about 0.5% to about 1%, or any range or sub-range therebetween.

[0062] Embodiments of the present disclosure may include phosphorus pentoxide (PO), on an oxide basis. Phosphorus pentoxide can act as a nucleating agent and promote crystal formation. Providing a minimum amount of phosphorus pentoxide (e.g., about 0.5% mole percent, on an oxide basis) can promote crystal formation. Thus, when a light diffuser is described herein as including an amorphous phase and / or a crystalline phase and a mole percent (or mole percent range) of phosphorus pentoxide or a phosphorus-containing component convertible to phosphorus pentoxide (e.g., "on an oxide basis") is listed, such mole percent (or mole percent range) refers to the total relative molar contribution of phosphorus pentoxide (e.g., as an initial formulation component) to all of the amorphous and / or crystalline species in the light diffuser. Consequently, increasing the phosphorus pentoxide content can increase the density of crystals in the glass-ceramic article. Limiting the phosphorus pentoxide content (e.g., about 5% mole percent, on an oxide basis, or less) can control the crystal density to achieve the transparency and haze values ​​described below. In some embodiments, the amount of phosphorus pentoxide, in mole % on an oxide basis, can be about 0.5% or more, about 1% or more, about 2% or less, or about 1.5% or less. In some embodiments, the amount of phosphorus pentoxide, in mole % on an oxide basis, can range from about 0.5% to about 2%, from about 0.5% to about 1.5%, from about 1% to about 2%, from about 1% to about 1.5%, or any range or sub-range therebetween.

[0063] Embodiments of the present disclosure may include zirconia (ZrO) on an oxide basis. Increasing the zirconia content can facilitate processing of the composition and / or glass-ceramic article without devitrification (e.g., by lowering the liquidus temperature). Limiting the zirconia content can prevent the formation of other crystalline phases. Thus, when a light diffuser is described herein as including an amorphous and / or crystalline phase and lists a mole percent (or mole percent range) of zirconia or a zirconium-containing component (e.g., "on an oxide basis") that can be converted to zirconia, such mole percent (or mole percent range) refers to the total relative molar contribution of zirconia (e.g., as an initial formulation component) to all of the amorphous and / or crystalline species in the light diffuser. In some embodiments, the amount of zirconia, in mole % on an oxide basis, can be about 1% or more, about 1.5% or more, about 2% or more, about 2.5% or more, about 3% or more, about 3.5% or more, about 5% or less, about 4% or less, about 3.5% or less, or about 3% or less. In some embodiments, the amount of zirconia, in mole % on an oxide basis, can range from about 1% to about 5%, about 1.5% to about 4%, about 1.5% to about 3.5%, about 1.5% to about 3%, about 1.5% to about 5%, about 2% to about 5%, about 2% to about 4%, about 2.5% to about 4%, about 3% to about 4%, about 3.5% to about 4%, or any range or sub-range therebetween.

[0064] Embodiments of the present disclosure may include boron oxide (BO) on an oxide basis. Increasing the boron oxide content can enable the resulting glass-ceramic article to withstand flexing and deformation without fracture and / or resist crack propagation. Additionally, increasing the boron oxide content can lower the liquidus temperature of the mixture, composition, and / or glass-ceramic article. Thus, when a light diffuser is described herein as comprising an amorphous and / or crystalline phase and recites a mole percent (or mole percent range) of boron oxide or a boron-containing component that can be converted to boron oxide (e.g., "oxide basis"), such mole percent (or mole percent range) refers to the total relative molar contribution of boron oxide (e.g., as an initial formulation component) to all of the amorphous and / or crystalline species in the light diffuser. In some embodiments, the amount of boron oxide, in mole % on an oxide basis, can be 0% or more, about 0.5% or more, about 1% or more, about 5% or less, about 3% or less, about 2% or less, or about 1% or less. In some embodiments, the amount of boron oxide, in mole %, on an oxide basis, can range from 0% to about 5%, 0% to about 3%, 0% to about 2%, 0% to about 1%, about 0.5% to about 5%, about 0.5% to about 3%, about 0.5% to about 2%, about 0.5% to about 1%, or any range or sub-range therebetween.

[0065] Embodiments of the present disclosure may include alkaline earth metal oxides, on an oxide basis. The alkaline earth metal oxides can help stabilize crystalline phases and / or solid solutions. In some embodiments, the total amount of alkaline earth metal oxides, on an oxide basis, in mole % can be 0% or more, about 0.5% or more, about 1% or more, about 5% or less, about 3% or less, or about 2% or less. In some embodiments, the total amount of alkaline earth metal oxides, on an oxide basis, in mole % can range from 0% to about 5%, 0% to about 3%, 0% to about 2%, about 0.5% to about 5%, about 0.5% to about 3%, about 0.5% to about 2%, about 1% to about 5%, about 1% to about 3%, about 1% to about 5%, or any range or sub-range therebetween.

[0066] Embodiments of the present disclosure may include zinc oxide (ZnO), on an oxide basis. Zinc oxide can help stabilize crystalline phases and / or solid solutions. Thus, when a light diffuser is described herein as including an amorphous phase and / or a crystalline phase and a mole percent (or mole percent range) of zinc oxide or a zinc-containing component convertible to zinc oxide (e.g., "on an oxide basis") is listed, such mole percent (or mole percent range) refers to the total relative molar contribution of zinc oxide (e.g., as an initial formulation component) to all of the amorphous and / or crystalline species in the light diffuser. In some embodiments, the amount of zinc oxide, on an oxide basis mole percent, can be 0% or more, about 0.5% or more, about 1% or more, about 2% or less, about 1.5% or less, or about 1% or less. In some embodiments, the amount of zinc oxide, in mole % on an oxide basis, can range from 0% to about 2%, 0% to about 1.5%, 0% to about 1%, 0.5% to about 1%, about 0.5% to about 2%, about 0.5% to about 1%, or any range or sub-range therebetween.

[0067] Embodiments of the present disclosure may include tin oxide (SnO2), on an oxide basis. While not intending to be bound by theory, tin oxide may render the resulting glass-ceramic article opaque. Providing small amounts of tin oxide (e.g., about 1% by mole percent, on an oxide basis) can increase the haze of a glass-ceramic article without significantly affecting light transmittance. Thus, when a light diffuser is described herein as comprising an amorphous and / or crystalline phase and a mole percent (or mole percent range) of tin oxide or a tin-containing component convertible to tin oxide (e.g., "on an oxide basis") is recited, such mole percent (or mole percent range) refers to the total relative molar contribution of tin oxide (e.g., as an initial formulation component) to all of the amorphous and / or crystalline species in the light diffuser. In some embodiments, the amount of tin oxide, on an oxide basis, may be about 0% or more, about 0.1% or more, about 0.5% or more, about 2% or more, about 1% or less, about 0.5% or less, or about 0.2% or less. In some embodiments, the amount of tin oxide, in mole % on an oxide basis, can range from 0% to about 2%, 0% to about 1%, 0% to about 0.5%, 0% to about 0.2%, 0% to about 0.1%, about 0.1% to about 5%, about 0.1% to about 2%, about 0.1% to about 1%, about 0.1% to about 0.5%, or any range or sub-range therebetween.

[0068] As used herein, a composition that is "substantially free" of a component means that the component has not been intentionally added to the composition and / or that the composition contains only trace amounts of the component, e.g., about 0.01 mole % on an oxide basis. In some embodiments, a mixture, composition, or glass-ceramic article can be substantially free of photosensitizers. Without intending to be bound by theory, photosensitizers may increase the absorption of one or more wavelengths of visible light, thereby decreasing transparency and / or imparting color to the mixture, composition, and / or glass-ceramic article. In some embodiments, the mixture, composition, or glass-ceramic article can be substantially free of photosensitizers including one or more of the following, on an oxide basis: titanium (TiO), iron (FeO), lead (PbO), arsenic (AsO), bismuth (BiO), molybdenum (MoO), tantalum (TaO), niobium (NbO), yttrium (YO), cadmium (CdO), and / or cerium (CeO). In some embodiments, the mixture, composition, or glass-ceramic article can be substantially free of precious metals. Without intending to be bound by theory, precious metals can increase reflectivity, which can reduce light transmittance and / or cause undesirable brightness variations (e.g., bright spots, gray spots). In some embodiments, the mixture, composition, or glass-ceramic article can be substantially free of precious metals, including one or more of the following, on an oxide basis: silver (AgO), gold (AuO), platinum (PtO), palladium (PdO), and / or rhenium (RhO). In some embodiments, the mixture, composition, and / or glass-ceramic article can be substantially free of fluorine (F) and / or fluorine-containing components. Without intending to be bound by theory, fluorine and / or fluorine-containing components may promote the formation of crystalline phases other than lithium disilicate, β-spodumene, and β-quartz (e.g., F-canasite, F-apatite), which may degrade the optical properties of the resulting glass-ceramic article and / or compete with other crystalline phases.

[0069] It should be understood that any of the above ranges for the components listed above may be combined in some embodiments of the present disclosure. Exemplary ranges for some embodiments of the present disclosure are provided in Table 1. R1 is the broadest range in Table 1, while R2 and R9 are the narrowest ranges in Table 1. R3-R8 and R10 represent intermediate ranges. Again, it should be understood that other ranges or subranges described above for these components may be used in combination with any of the ranges provided in Table 1.

[0070] [Table 1]

[0071] The mixture, composition, and / or glass-ceramic article may have a liquidus temperature and / or liquidus viscosity. As used herein, "liquidus temperature" refers to the lowest temperature above which crystals cannot exist in a material (e.g., the material is completely liquid). In other words, the liquidus temperature is the highest temperature at which crystals can coexist with the liquid (e.g., melt, molten) phase of the material in thermodynamic equilibrium. In some embodiments, the liquidus temperature can be about 1000°C or higher, about 1030°C or higher, about 1050°C or higher, about 1075°C or higher, about 1250°C or lower, about 1220°C or lower, about 1100°C or lower, or about 1085°C or lower. In some embodiments, the liquidus temperature can range from about 1000°C to about 1250°C, from about 1000°C to about 1220°C, from about 1000°C to about 1100°C, from about 1000°C to about 1085°C, from about 1030°C to about 1085°C, from about 1050°C to about 1080°C, from about 1030°C to about 1250°C, from about 1030°C to about 1220°C, from about 1050°C to about 1220°C, from about 1075°C to about 1220°C, from about 1075°C to about 1100°C, or any range or sub-range therebetween.

[0072] As used herein, "liquidus viscosity" refers to the viscosity of a material when the material is at its liquidus temperature. Viscosity at the liquidus temperature is measured using ASTM C965-96(2017). In some embodiments, the liquidus viscosity can be about 80 Pascal-seconds (Pa·s) or greater, about 100 Pa·s or greater, about 140 Pa·s or greater, about 200 Pa·s or greater, about 300 Pa·s or greater, about 1,000 Pa·s or less, about 600 Pa·s or less, about 500 Pa·s or less, or about 300 Pa·s or less. In some embodiments, the liquidus viscosity can range from about 80 Pascal seconds (Pa·s) to about 1,000 Pa·s, from about 80 Pa·s to about 600 Pa·s, from about 100 Pa·s to about 600 Pa·s, from about 140 Pa·s to about 600 Pa·s, from about 140 Pa·s to about 500 Pa·s, from about 140 Pa·s to about 300 Pa·s, from about 200 Pa·s to about 300 Pa·s, from about 140 Pa·s to about 1,000 Pa·s, from about 200 Pa·s to about 1,000 Pa·s, from about 200 Pa·s to about 600 Pa·s, from about 200 Pa·s to about 500 Pa·s, from about 300 Pa·s to about 500 Pa·s, or any range or sub-range therebetween.

[0073] FIG. 1 illustrates an exemplary embodiment of a light diffuser 103 made from a glass-ceramic article. The light diffuser can have a first major surface 111 and a second major surface 113 opposite the first major surface 111. In some embodiments, such as those illustrated, the first major surface 111 can be planar. In some embodiments, such as those illustrated, the second major surface 113 can be planar. In some embodiments, such as those illustrated, the first major surface 111 can be substantially parallel to the second major surface 113. In some embodiments, the light diffuser can have one or more edges extending between the first major surface 111 and the second major surface 113. The thickness 115 of the light diffuser can be defined as the distance between the first major surface 111 and the second major surface 113, averaged over the first major surface 111. In some embodiments, the thickness 115 of the light diffuser 103 can be about 0.1 millimeters (mm) or more, about 0.5 mm or more, about 0.8 mm or more, about 1 mm or more, about 10 mm or less, about 8 mm or less, about 5 mm or less, about 3 mm or less, or about 2 mm or less. In some embodiments, the thickness 115 of the light diffuser 103 can range from about 0.1 mm to about 10 mm, about 0.1 mm to about 8 mm, about 0.5 mm to about 8 mm, about 0.5 mm to about 5 mm, about 0.5 mm to about 3 mm, about 0.5 mm to about 2 mm, about 1 mm to about 2 mm, about 0.5 mm to about 10 mm, about 1 mm to about 10 mm, about 1 mm to about 8 mm, about 1 mm to about 5 mm, about 1 mm to about 3 mm, or any range or sub-range therebetween.

[0074] The glass-ceramic article may include one or more crystalline phases. Crystalline phases and crystallite sizes can be determined using X-ray diffraction (XRD). For example, as shown in FIG. 4, when the scattering angle double angle 401 is plotted against the detected intensity 403, a unique series of peaks 405 is associated with a given crystalline phase. As can be seen, the peaks 405 can be associated with β-quartz 407 (open squares), β-spodumene 409 (diamonds), lithium disilicate 411 (circles), and trace amounts of lithiophosphate 413 (triangles).

[0075] One or more crystalline phases and / or crystal size distribution can be determined using image analysis of scanning electron microscope (SEM) images. For example, Figures 2-3 show schematic SEM images of some embodiments of the present disclosure. In some embodiments, the sample area of ​​the SEM images is approximately 25 μm 2 to about 100 μm 2 , for example, about 49 μm 2 to approximately 81 μm 2 In some embodiments, the particle size measurements of the crystals for determining the particle size distribution represent the average size of the crystals. In further embodiments, the particle size measurements of β-quartz and / or β-spodumene may include the approximate radius of crystals having a substantially circular cross-section in an SEM image. For example, FIG. 5 shows a cumulative distribution 505 of particle sizes for crystals having a substantially circular cross-section with a median 507 (50th percentile) particle size of about 600 nanometers (nm). In FIG. 5, the horizontal axis (e.g., x-axis) 501 represents particle size measurements, and the vertical axis (e.g., y-axis) 503 represents the cumulative percentage of crystals. In some embodiments, the median particle size can be about 500 nm or more, about 550 nm or more, about 600 nm or more, about 650 nm or more, about 700 nm or more, about 1,000 nm or less, about 900 nm or less, about 800 nm or less, about 750 nm or less, or about 700 nm or less. In some embodiments, the median particle size can range from about 500 nm to about 1,000 nm, from about 500 nm to about 900 nm, from about 500 nm to about 800 nm, from about 550 nm to about 800 nm, from about 600 nm to about 800 nm, from about 650 nm to about 800 nm, from about 700 nm to about 800 nm, from about 500 nm to about 800 nm, from about 500 nm to about 700 nm, from about 550 nm to about 700 nm, from about 600 nm to about 700 nm, or any range or sub-range therebetween. Providing crystals having a median particle size ranging from about 500 nanometers to about 1,000 nanometers (e.g., about 600 nanometers to about 800 nanometers) can increase scattering of visible light (e.g., 380 nanometers to about 740 nanometers, about 400 nanometers to about 700 nanometers), which can increase the haze and hiding power of the glass-ceramic article with respect to visible light.

[0076] In some embodiments, one or more crystalline phases and / or crystals can be dispersed throughout the volume of a glass-ceramic article (e.g., a light diffuser). As used herein, crystalline phases and / or crystals are "dispersed throughout the volume" of a glass-ceramic article if the one or more crystalline phases or crystals do not intersect with a major surface or edge of the glass-ceramic article (e.g., a light diffuser). In further embodiments, the one or more crystalline phases can be substantially uniformly dispersed throughout the volume of the light diffuser.

[0077] In some embodiments, a glass-ceramic article can include lithium disilicate crystals. In further embodiments, the lithium disilicate crystals can be dispersed throughout the volume of the glass-ceramic article (e.g., a light diffuser). In further embodiments, the lithium disilicate crystals can be substantially interconnected. As used herein, "interconnected" crystals means that crystals of one crystal type are within the median particle size of other crystals of the same crystal type. Providing lithium disilicate crystals can enhance the mechanical stability and strength of a glass-ceramic article. Providing substantially interconnected lithium disilicate crystals can further enhance the mechanical stability and strength of a glass-ceramic article. Without intending to be bound by theory, for example, substantially interconnected lithium disilicate crystals can enhance the mechanical stability and strength because they cause cracks propagating through the glass-ceramic article (e.g., a light diffuser) to take a tortuous path that avoids the crystals.

[0078] In some embodiments, the glass-ceramic article can include β-spodumene crystals. In further embodiments, β-spodumene can constitute the predominant crystalline phase in a glass-ceramic article (e.g., a light diffuser). As used herein, a crystalline type is predominant in a crystalline phase if the total volume of all crystals of that crystalline type occupies a greater volume than any of the other crystalline types (e.g., a plurality, a majority). In further embodiments, β-spodumene crystals can be dispersed throughout the volume of the glass-ceramic article (e.g., a light diffuser). In further embodiments, the glass-ceramic article can include both lithium disilicate crystals and β-spodumene crystals. Without intending to be bound by theory, β-spodumene crystals can increase the light scattering of the glass-ceramic article, thereby increasing the haze and hiding power of the glass-ceramic article. In some embodiments, a median grain size distribution can be measured for β-spodumene crystals. In further embodiments, a median grain size distribution can be measured for β-spodumene crystals having a substantially circular cross-section. In further embodiments, the median crystal size distribution measured for the β-spodumene crystals can fall within one or more of the ranges described above (e.g., about 500 nm to about 1,000 nm, about 600 nm to about 800 nm).

[0079] In some embodiments, the glass-ceramic article can include β-quartz crystals. In further embodiments, β-quartz can constitute a predominant crystalline phase in the glass-ceramic article (e.g., a light diffuser). In further embodiments, β-quartz crystals can be dispersed throughout the volume of the glass-ceramic article (e.g., a light diffuser). In further embodiments, the glass-ceramic article can include both lithium disilicate crystals and β-quartz crystals. In still further embodiments, the glass-ceramic article can include lithium disilicate crystals, β-spodumene crystals, and β-quartz crystals. Without intending to be bound by theory, β-quartz crystals can increase the light scattering of the glass-ceramic article, thereby increasing the haze and hiding power of the glass-ceramic article. In some embodiments, a median grain size distribution can be measured for β-quartz crystals. In further embodiments, a median grain size distribution can be measured for β-quartz crystals having a substantially circular cross-section. In further embodiments, the median crystal size distribution measured for the β-quartz crystals can fall within one or more of the ranges set forth above (eg, from about 500 nm to about 1,000 nm, from about 600 nm to about 800 nm).

[0080] In some embodiments, a glass-ceramic article (e.g., a light diffuser) can have a light transmittance. As used herein, light transmittance is measured in the visible range of 400 nm to 700 nm by averaging light transmittance measurements for integer wavelengths from about 400 nm to about 700 nm through a glass-ceramic article having a thickness of 1.2 mm. Light transmittance was measured using a Perkin Elmer 950 UV-Vis-NIR spectrophotometer, using a tungsten halogen light source and an InGaAs light source, making measurements every 2 nm in the visible range. In some embodiments, the light transmittance can be about 40% or more, about 45% or more, about 50% or more, about 70% or less, about 60% or less, or about 55% or less. In some embodiments, the light transmittance can range from about 40% to about 70%, about 40% to about 60%, about 40% to about 55%, about 45% to about 55%, about 50% to about 55%, about 45% to about 70%, about 45% to about 60%, about 50% to about 60%, or any range or sub-range therebetween. By providing a glass-ceramic article with a high light transmittance (e.g., about 40% or greater, about 50% or greater), the transmission of light can be effectively increased, thereby increasing illumination from the display device and reducing the amount of energy from the illumination source that is lost as heat, which can further increase the stability of the display device.

[0081] In some embodiments, the glass-ceramic article (e.g., a light diffuser) can have haze. As used herein, haze refers to transmission haze measured according to ASEM E430. Haze is measured using a haze meter supplied by BYK Gardner under the trade name HAZE-GUARD PLUS, using an aperture above the light source port. The aperture diameter is 8 mm. A CIE D65 light source is used as the light source to illuminate the folding device. Haze is measured through a glass-ceramic article having a thickness of 1.2 mm. In further embodiments, the haze measured over a range of about 2° to about 10° relative to an angle of incidence normal to the second major surface 113 of the light diffuser 103 can be about 90% or more, about 95% or more, about 100% or more, about 150% or less, about 120% or less, about 110% or less, or about 105% or less. In further embodiments, the haze at about 0° relative to an angle of incidence normal to the second major surface 113 of the light diffuser 103 can range from about 90% to about 150%, about 90% to about 120%, about 90% to about 110%, about 90% to about 105%, about 95% to about 105%, about 100% to about 105%, about 95% to about 150%, about 100% to about 150%, about 100% to about 120%, about 100% to about 110%, or any range or sub-range therebetween. By providing a glass-ceramic article with a high haze, the luminance uniformity of a thin light diffuser can be increased.

[0082] In some embodiments, a glass-ceramic article (e.g., a light diffuser) can have an integrated light transmittance. As used herein, integrated light transmittance is measured using the apparatus for measuring light transmittance described above, in which a reflectance disk is placed over the entrance window hole of a spectrophotometer. A Spectralon SRM-99 reflectance disk was used to measure light transmittance over a wide angular range. As previously described for light transmittance, integrated light transmittance is measured in the visible light range of 400 nm to 700 nm by averaging measurements of integer wavelengths from about 400 nm to about 700 nm through a glass-ceramic article having a thickness of 1.2 mm. In further embodiments, the integrated light transmittance can be about 40% or more, about 50% or more, about 60% or more, about 80% or less, about 70% or less, or about 60% or less. In further embodiments, the integrated light transmittance can range from about 40% to about 80%, about 40% to about 70%, about 40% to about 60%, about 50% to about 60%, about 50% to about 80%, about 50% to about 70%, about 60% to about 80%, about 60% to about 70%, or any range or sub-range therebetween. By providing a glass-ceramic article with a high integrated light transmittance (e.g., about 40% or greater, about 50% or greater), the transmission of light can be effectively increased, thereby increasing illumination from the display device and reducing the amount of energy from the illumination source that is lost as heat, which can further increase the stability of the display device.

[0083] In some embodiments, a glass-ceramic article (e.g., a light diffuser) can include a color shift. As used herein, color shift is measured as the ratio of light transmittance measured at 600 nm visible light to reflectance measured at 420 nm visible light divided by 1. In further embodiments, the color shift can be about -0.1 or greater, about 0 or greater, about 0.1 or greater, about 0.5 or less, about 0.2 or less, or about 0.1 or less. In further embodiments, the color shift can range from about -0.1 to about 0.5, about -0.1 to about 0.2, about 0 to about 0.2, about 0 to about 0.1, about 0 to about 0.5, about 0.1 to about 0.5, about 0.1 to about 0.2, or any range or subrange therebetween.

[0084] In some embodiments, a glass-ceramic article (e.g., a light diffuser) may have a hiding power. As used herein, hiding power is measured using a test fixture 601 shown in FIG. 6. As can be seen, a series of LED light sources 603 are spaced apart at a predetermined pitch 605. A light diffuser 103 to be tested, having a thickness 115, is positioned an optical distance 607 away from the LED light sources 603. The luminance intensity is measured at the second major surface 113 of the light diffuser 103, and luminance uniformity is determined for the corresponding optical distance 607. The luminance uniformity is defined as the ratio of the minimum luminance to the maximum luminance measured in the direction of the pitch 605. The optical distance 607 is adjusted in 1 mm increments to determine the minimum optical distance at which the luminance uniformity measured at the second major surface 113 of the light diffuser 103 is 98% or greater. A pitch 605 of 10 mm is used. In further embodiments, the hiding power may be about 1 mm or more, about 2 mm or more, about 5 mm or more, about 10 mm or more, about 50 mm or less, about 20 mm or less, or about 10 mm or less. In further embodiments, the hiding power may range from about 1 mm to about 50 mm, about 1 mm to about 20 mm, about 1 mm to about 10 mm, about 2 mm to about 10 mm, about 5 mm to about 10 mm, about 2 mm to about 50 mm, about 5 mm to about 50 mm, about 5 mm to about 20 mm, about 10 mm to about 20 mm, or any range or sub-range therebetween.

[0085] In some embodiments, such as that shown in FIG. 1 , the light diffuser 103 can be incorporated into the display device 101. In further embodiments, the display device 101 can include a light source 105. In even further embodiments, the light source 105 can include a light guide plate. In even further embodiments, the light source 105 can include one or more of a light emitting diode (LED), an organic light emitting diode (OLED), a laser, a tungsten bulb, or a gas-filled discharge lamp, including fluorescent, neon, argon, xenon, and high-energy arc discharge lamps. In even further embodiments, such as those shown, the first major surface 111 of the light diffuser 103 can face the light source 105, and the second major surface 113 of the light diffuser 103 can face the user 109. In even further embodiments, the display device 101 can include a visual display 107. In even further embodiments, the visual display 107 can include a plurality of pixels. In even further embodiments, the visual display 107 can include a liquid crystal display (LCD). In yet further embodiments, as shown, the second major surface of the light diffuser 103 can face the display device 107. In yet further embodiments, as shown, the light diffuser 103 can be disposed between the light source 105 and the image display device 107. As can be seen, the light source 105 can emit light 102 toward the light diffuser, which can increase the luminance uniformity of the emitted light 102 and transmit the diffused light 104 toward the image display device 107 where it can be viewed by a user 109. In some embodiments, the glass-ceramic article (e.g., the light diffuser 103) can be used in photovoltaic devices, windshields, photolithography, and imaging applications.

[0086] An embodiment of a method for manufacturing a glass-ceramic article (eg, a light diffuser) according to an embodiment of the present disclosure will be discussed with reference to the flow diagram of FIG.

[0087] In a first step 701 of a method of manufacturing a glass-ceramic article (e.g., light diffuser 103), the method can begin by forming a mixture by melting together the above-mentioned components that fall within one or more of the ranges set forth above and in Table 1.

[0088] After step 701, the method may proceed to step 703, which includes forming a ribbon from the mixture produced in step 701. In some embodiments, the ribbon may have a first major surface and a second major surface opposite the first major surface. In further embodiments, the thickness of the ribbon defined between the first and second major surfaces may be within one or more of the ranges for thickness of the glass-ceramic article set forth above. In some embodiments, the ribbon may be formed by rolling. In some embodiments, the ribbon may be formed using a slot draw technique. In some embodiments, the ribbon may be formed using a float draw technique. In some embodiments, the ribbon may be formed by pressing the mixture into a mold.

[0089] After step 703, the method can proceed with heating the ribbon. In some embodiments, heating the ribbon can include step 705, which includes heating the ribbon to a nucleation temperature for a nucleation time. Without intending to be bound by theory, the nucleation temperature can enable crystal nucleation and / or facilitate control of crystal density in the resulting glass-ceramic ribbon (e.g., a light diffuser). Providing a mixture and / or composition having a liquidus viscosity of about 80 Pa·s or greater and / or a liquidus temperature of about 1000°C or greater can facilitate processing of the mixture, composition, and / or glass-ceramic ribbon. In further embodiments, the nucleation temperature can be about 550°C or greater, about 580°C or greater, about 600°C or greater, about 650°C or greater, about 800°C or less, about 750°C or less, or about 700°C or less. In further embodiments, the nucleation temperature can range from about 550° C. to about 800° C., from about 580° C. to about 800° C., from about 580° C. to about 750° C., from about 600° C. to about 750° C., from about 600° C. to about 700° C., from about 650° C. to about 700° C., from about 550° C. to about 750° C., from about 550° C. to about 700° C., or any range or sub-range therebetween. In further embodiments, the nucleation time can be about 0.25 hours or more, about 0.5 hours or more, about 1 hour or more, about 2 hours or more, about 24 hours or less, about 6 hours or less, about 4 hours or less, or about 2 hours or less. In further embodiments, the nucleation temperature can range from about 0.25 hours to about 24 hours, from about 0.25 hours to about 6 hours, from about 0.5 hours to about 6 hours, from about 0.5 hours to about 4 hours, from about 1 hour to about 4 hours, from about 2 hours to about 4 hours, from about 0.5 hours to about 2 hours, or from about 1 hour to about 2 hours, or any range or sub-range therebetween.

[0090] In some embodiments, heating the ribbon can include step 707, which includes heating the ribbon to a crystallization temperature for a crystallization time. In further embodiments, the method can proceed from step 705 to step 707. In further embodiments, the method can proceed directly from step 703 to step 707. Without intending to be bound by theory, the crystallization temperature can promote crystal growth and / or the crystallization time can allow for control of the size distribution (e.g., median particle size) of the crystals in the resulting glass-ceramic article (e.g., a light diffuser). In further embodiments, the crystallization temperature can be about 825°C or greater, about 850°C or greater, about 860°C or greater, about 900°C or less, about 875°C or less, or about 850°C or less. In further embodiments, the crystallization temperature may range from about 825° C. to about 900° C., from about 825° C. to about 875° C., from about 850° C. to about 875° C., from about 850° C. to about 900° C., from about 850° C. to about 875° C., from about 860° C. to about 900° C., from about 860° C. to about 875° C., or any range or sub-range therebetween. In further embodiments, the crystallization time may be about 0.25 hours or more, about 0.5 hours or more, about 1 hour or more, about 2 hours or more, about 24 hours or less, about 6 hours or less, about 4 hours or less, or about 2 hours or less. In further embodiments, the crystallization time may range from about 0.25 hours to about 24 hours, from about 0.25 hours to about 6 hours, from about 0.5 hours to about 6 hours, from about 0.5 hours to about 4 hours, from about 1 hour to about 4 hours, from about 2 hours to about 4 hours, from about 0.5 hours to about 2 hours, or from about 1 hour to about 2 hours, or any range or sub-range therebetween.

[0091] In some embodiments, the method can proceed to step 709, which includes terminating the method. In further embodiments, the result of this method can be a glass-ceramic article. In still further embodiments, the glass-ceramic article can include a light diffuser having the light transmittance, haze, integrated light transmittance, hiding power, color shift, and / or median particle size described above. In further embodiments, step 709 can include assembling a display device (e.g., FIG. 1 ) including the glass-ceramic article, a light source, and a visual display device. In some embodiments, a method of making a glass-ceramic article (e.g., a light diffuser, a display device) can proceed sequentially through steps 701, 703, 707, and 709 as previously described, including heating the ribbon to a crystallization temperature for a crystallization time without heating the ribbon to a nucleation temperature for a nucleation time. In some embodiments, arrow 702 can be followed from step 703 to step 705, which includes heating the ribbon to a nucleation temperature for a nucleation time, before following arrow 704, which leads to heating the ribbon to a crystallization temperature for a crystallization time. In some embodiments, arrow 702 can be followed from step 703 to step 705, which includes heating the ribbon to a nucleation temperature for a nucleation time, before following arrow 706, which leads to step 709, eliminating step 707. It should be understood that in some embodiments, the above variations can be combined. [Example]

[0092] The following examples further clarify various embodiments. Table 2 contains compositional information for Examples A-K expressed in mole percent on an oxide basis, while Table 3 contains the optical properties of Examples A-K. Table 4 contains heat treatment conditions for Examples C-K. Table 5 contains compositional information for Examples 1-13 expressed in mole percent on an oxide basis, while Table 6 contains the properties of Examples 1-13.

[0093] [Table 2]

[0094] [Table 3]

[0095] [Table 4]

[0096] [Table 5]

[0097] [Table 6]

[0098] The compositions in Table 2 compare compositions within the ranges set forth above for embodiments of the present disclosure (Table 1) with compositions outside those ranges. Examples C-K fall within one or more of the ranges set forth above for embodiments of the present disclosure (Table 1). Examples A-B fall outside one or more of the ranges set forth above. For example, in Example A, the alumina and phosphorus pentoxide contents are too high, the lithium oxide, sodium oxide, and zirconia contents are too low, and titanium dioxide is included. For example, in Example B, the lithium oxide and zirconia contents are too high, the alumina content is too low, and yttrium oxide is included.

[0099] The optical properties of Examples A-K are shown in Table 3. Example A has high haze (99.6%) but low light transmittance (0.06%). Similarly, Example B has high haze (100%) but low light transmittance (6.04%). As a result, Examples A-B would be highly inefficient as light diffusers because very little light is transmitted. In contrast, Examples E-K have high haze (greater than 100%, e.g., 101% to 103%) and high light transmittance (greater than 50%, e.g., 53% to 59%). As a result, Examples E-K have haze and light transmittance properties that are predicted to correlate well with good hiding power and high luminous efficacy. Compared to Examples A-B, Examples E-K exhibit an unexpected result in that their compositional differences result in both high haze and high light transmittance that are not readily achieved by Examples A-B or expected for similar compositions.

[0100] As discussed below, the differences in optical properties are explained by the differences in heat treatment of Examples E-K compared to Examples C-D. Even though Examples C-D have the same composition on an oxide basis as Examples E-K, Example C has very low haze (0.1%) and Example D has lower light transmittance (45%) than either of Examples E-K.

[0101] Table 4 shows the heat treatment of Examples C-K. As previously mentioned, Examples E-K have haze values ​​of 100% or greater and light transmittance values ​​of 50%. Examples E-K were processed at crystallization temperatures of about 850°C or greater for crystallization times of about 0.5 hours or greater. In contrast, the crystallization temperature of Example C was 740°C, which resulted in a low haze value. Without intending to be bound by theory, using a sufficiently high crystallization temperature may promote crystal growth, which can enable high haze.

[0102] In some embodiments, heating the composition to a nucleation temperature for a nucleation time can simultaneously enable higher haze and higher light transmittance than if the heat treatment were omitted. In other embodiments, the step of heating the composition to a nucleation temperature for a nucleation time can be omitted, as shown in Examples J-K. Example H had the highest haze value (103%) and the highest light transmittance (58.9%), which was processed at a nucleation temperature of 580°C for a nucleation time of 4 hours. Example I was processed identically to Example H, except that the nucleation temperature was 700°C for Example I and 580°C for Example H, resulting in higher light transmittance. As a result, lowering the nucleation temperature from 700°C to 580°C can increase the light transmittance of the resulting glass-ceramic article (e.g., a light diffuser).

[0103] Table 5 lists compositions according to embodiments of the present disclosure. Examples C-J in Tables 2-4 are the same as Example 1 in Table 5, and Example K in Tables 2-4 is the same as Example 2 in Table 5. While optical properties are not reported for Examples 3-13, it is expected that optical properties similar to those of Examples C-K would be obtained by corresponding heat treatment. Table 6 lists the liquidus properties, i.e., liquidus temperature and liquidus viscosity, for Examples 1-13. The liquidus temperatures range from 1030°C (Example 2) to 1220°C (Example 13). The liquidus viscosities range from 88 Pa·s (Example 13) to 980 Pa·s (Example 10). As previously mentioned, certain components affect the liquidus viscosity, while other components affect the devitrification and liquidus temperature.

[0104] The schematic SEM image in Figure 2 corresponds to Example 1 in Table 5, where the heat treatment included heating the composition to a nucleation temperature of 700°C for a nucleation time of 1 hour, followed by heating to a crystallization temperature of 860°C for a crystallization time of 4 hours. As shown in Figure 2, crystals 203 (e.g., β-quartz and / or β-spodumene crystals) may be surrounded by an amorphous glass phase 201. As can be seen, the crystals may have a circular cross-section, although some crystals appear to be adjacent to each other, directly adjacent to each other, and / or continuous at the resolution shown in Figure 2. The grain size distribution measured from the sample shown in Figure 2 is shown in Figure 5. As can be seen, the median grain size shown in Figure 5 is approximately 600 nm.

[0105] The schematic SEM image in FIG. 3 corresponds to Example 2 in Table 5, where the heat treatment included heating the composition to a crystallization temperature of 850° C. for a crystallization time of 0.33 hours. As shown in FIG. 3 , crystals 303 (e.g., β-quartz and / or β-spodumene crystals) may be surrounded by an amorphous glass phase 301. As with the sample shown in FIG. 2 , the crystals 303 in FIG. 3 may have a circular cross-section, although some crystals appear to be close to each other, directly adjacent to each other, and / or continuous at the resolution shown in FIG. 3 . Compared to the crystals 203 in FIG. 2 , the crystals 303 in FIG. 3 are denser and generally smaller, with a correspondingly smaller particle size distribution and median particle size. This illustrates how heat treatment can affect the resulting crystal structure; for example, omitting the nucleation temperature / time can result in smaller crystals.

[0106] An X-ray diffraction (XRD) analysis of an example corresponding to Figure 3 is shown in Figure 4. As shown in Figure 4, the peak of greatest intensity 405 contains β-quartz 407 (white squares). In Figure 4, smaller peaks 405 correspond to β-spodumene 409 (diamonds) and lithium disilicate 411 (circles). Even trace amounts of lithiophosphate 413 (triangles) are detectable in Figure 4. Comparing Figure 2 with Figure 3, the grain size of the crystals in Figure 3 is smaller than in Figure 2, which corresponds to less light scattering at visible wavelengths and, consequently, lower haze.

[0107] The above disclosure provides compositions and resulting glass-ceramic articles that can provide high illuminance, high brightness uniformity, thermal dimensional stability, mechanical stability, and a thin light diffuser. The compositions of the present disclosure can simultaneously provide high light transmittance (e.g., about 40% or more, about 40% to about 70%) and high haze (e.g., 95% or more, about 100% to about 105%). Providing a glass-ceramic article with high light transmittance and high haze can, for example, efficiently transmit light while increasing brightness uniformity, thereby increasing illumination from a display device and reducing the amount of energy from the illumination source lost as heat, and can function as a diffuser to further improve the stability of the display device. Providing lithium disilicate crystals can enhance the mechanical stability and strength of the glass-ceramic article. Furthermore, providing substantially interconnected lithium disilicate crystals can further enhance the mechanical stability and strength of the glass-ceramic article. Providing β-spodumene crystals or β-quartz crystals can increase the light scattering of the glass-ceramic article, thereby increasing the haze and hiding power of the glass-ceramic article. Furthermore, providing crystals having a median particle size ranging from about 500 nanometers to about 1,000 nanometers (e.g., 600 nanometers to about 800 nanometers) can increase scattering of visible light (e.g., from about 380 nanometers to about 740 nanometers, from about 400 nanometers to about 700 nanometers), thereby increasing the haze and hiding power of the glass-ceramic article with respect to visible light. The formation of the above-mentioned crystals can be promoted by providing an alkali-containing aluminosilicate and / or alkali-containing aluminoborosilicate composition containing a high mole percent (mol%) of lithium (e.g., from about 17% or more, from about 20% to about 25%) on an oxide basis and low aluminum (e.g., from about 10% or less, from about 3% to about 9%). Nucleation of such crystals can be promoted by providing a composition containing phosphorus (e.g., from about 1% to about 2% on an oxide basis).Heating compositions of embodiments of the present disclosure to a crystallization temperature ranging from about 850°C to about 900°C can promote crystal formation and controlled crystal growth. Additionally, heating the composition to a nucleation temperature ranging from about 550°C to about 800°C prior to heating the composition to the crystallization temperature can increase the density of crystals and / or improve control over crystal growth. Providing compositions with a liquidus viscosity of about 80 Pascal-seconds or greater and / or a liquidus temperature of about 1000°C or greater can facilitate processing of glass-ceramic articles and precursors.

[0108] Any directional terms used herein—e.g., up, down, right, left, front, back, top, bottom—are used only with reference to the drawings depicted and are not intended to imply absolute orientation.

[0109] It will be recognized that various disclosed embodiments may include features, elements, or steps that are described with respect to that embodiment. It will also be recognized that features, elements, or steps, although described with respect to one embodiment, may be interchanged or combined in alternative embodiments in various undescribed combinations or permutations.

[0110] It should also be understood that, as used herein, nouns refer to "at least one" of the reference, and should not be limited to "only one" of the reference, unless otherwise specified. For example, reference to an "element" includes embodiments having two or more of such elements, unless the context clearly indicates otherwise. Similarly, the term "plurality" is intended to indicate "greater than one."

[0111] As used herein, the term "about" means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but are approximate and / or may be larger or smaller, as necessary, reflecting tolerances, conversion factors, rounding, measurement error, and the like, as well as other factors known to those of ordinary skill in the art. Ranges may be stated herein as from "about" one particular value and / or to "about" another particular value. When such a range is expressed, an embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, by the use of the antecedent "about," it will be understood that the particular value forms another embodiment. Whether or not the specification refers to a numerical value or range endpoint as "about," it is intended that the endpoint of that numerical value or range include two embodiments: one modified by "about" and one not modified by "about." It will be further understood that each endpoint of a range is significant both in relation to the other endpoint, and independently of the other endpoint.

[0112] As used herein, the terms "substantially," "substantially," and variations thereof, unless otherwise specified, are intended to indicate that a described characteristic is equal to or approximately equal to a value or description. For example, a "substantially flat" surface is intended to indicate a surface that is flat or substantially flat. Furthermore, as defined above, "substantially similar" is intended to indicate that two values ​​are equal or approximately equal. In some embodiments, "substantially similar" may refer to values ​​that are within about 10% of each other, e.g., within about 5% of each other, or within about 2% of each other.

[0113] Unless otherwise expressly stated, it is in no way intended that any method described herein be construed as requiring that its steps be performed in a particular order. Thus, unless a method claim actually recites the order in which its steps should be followed, or unless the claim or description otherwise specifically states that the steps are to be limited to a particular order, no particular order is intended to be implied in any way.

[0114] Although various features, elements, or steps of particular embodiments may be disclosed using the transitional phrase "comprising," it should be understood that alternative embodiments are implied, including those that may be described using the transitional phrases "consisting of" or "consisting essentially of." Thus, for example, alternative embodiments implied for a device comprising A+B+C include embodiments in which the device consists of A+B+C, and embodiments in which the device consists essentially of A+B+C. As used herein, the terms "comprising" and "comprising," and variations thereof, are intended to be synonymous and open-ended, unless otherwise expressly stated.

[0115] The above embodiments, and features of those embodiments, are exemplary and may be provided alone or in any combination with any one or more features of the other embodiments provided herein without departing from the scope of the present disclosure.

[0116] It will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the spirit and scope of the disclosure. Thus, the present disclosure is intended to cover modifications and variations of the embodiments herein, provided they come within the scope of the appended claims and their equivalents.

[0117] Preferred embodiments of the present invention will be described below in detail.

[0118] Embodiment 1 In the light diffuser, an amorphous phase, and a crystalline phase comprising lithium disilicate and one or more of beta-spodumene or beta-quartz having a median particle size ranging from about 500 nanometers to about 1,000 nanometers, the crystalline phase being dispersed throughout the volume of the light diffuser; Including, The light diffuser comprises, expressed as mole percent on an oxide basis: 60-75 mol% SiO2, 2 to 9 mol% Al2O3, 17-25 mol% LiO, and 0.5 to 6 mol% Na2O+K2O, a light diffuser including:

[0119] Embodiment 2 Expressed as mole % on an oxide basis, 0.5 to 2 mol% P2O5, 0.2 to 8 mol% ZrO2, 0-5 mol% B2O3, 0-5 mol% MgO+CaO+SrO, 0-2 mol% ZnO, and 0-2 mol% SnO2, 2. The light diffuser of embodiment 1, further comprising:

[0120] Embodiment 3 The light diffuser comprises, expressed as mole percent on an oxide basis: 67-70 mol% SiO2, 2.5 to 4.5 mol% Al2O3, 21-24 mol% LiO, 0.5 to 2 mol% NaO, 0 to 1 mol% K2O, 1-2 mol% P2O5, 1.5 to 4 mole percent ZrO2, and 0.1 mol% SnO2, 3. The light diffuser of embodiment 2, comprising:

[0121] Embodiment 4 4. The light diffuser of any one of embodiments 1 to 3, wherein beta-spodumene predominates.

[0122] Embodiment 5 4. The light diffuser of any one of embodiments 1 to 3, wherein the light diffuser is predominantly beta-quartz.

[0123] Embodiment 6 6. The light diffuser of any one of embodiments 1 to 5, wherein the median particle size of one or more crystal types of the crystals ranges from about 600 nanometers to about 800 nanometers.

[0124] Embodiment 7 6. The light diffuser of any one of embodiments 1 to 5, wherein the lithium disilicate crystals are substantially connected.

[0125] Embodiment 8 8. The light diffuser of any one of embodiments 1 to 7, further comprising a first major surface and a second major surface opposite the first major surface, wherein a thickness defined between the first major surface and the second major surface ranges from about 0.5 millimeters to about 5 millimeters.

[0126] Embodiment 9 9. The light diffuser of embodiment 8, wherein the thickness of the light diffuser ranges from about 0.8 millimeters to about 1.5 millimeters.

[0127] Embodiment 10 10. The light diffuser of any one of the preceding embodiments, wherein the light diffuser has a light transmittance ranging from about 40% to about 70%.

[0128] Embodiment 11 11. The light diffuser of embodiment 10, wherein the light transmittance of the light diffuser ranges from about 50% to about 60%.

[0129] Embodiment 12 12. The light diffuser of any one of the preceding embodiments, wherein the light diffuser has a haze of about 95% or greater.

[0130] Embodiment 13 13. The light diffuser of embodiment 12, wherein the haze of the light diffuser ranges from about 100% to about 105%.

[0131] Embodiment 14 14. The light diffuser of any one of the preceding embodiments, wherein the light diffuser has an integrated light transmittance of about 40% or greater.

[0132] Embodiment 15 15. The light diffuser of embodiment 14, wherein the integrated light transmittance of the light diffuser ranges from about 50% to about 70%.

[0133] Embodiment 16 16. The light diffuser of any one of the preceding embodiments, wherein the light diffuser has a hiding power of about 20 millimeters or less.

[0134] Embodiment 17 17. The light diffuser of embodiment 16, wherein the hiding power of the light diffuser ranges from about 1 millimeter to about 10 millimeters.

[0135] Embodiment 18 18. The light diffuser of any one of the preceding embodiments, wherein the light diffuser has a color shift of about 0.2 or less.

[0136] Embodiment 19 19. The light diffuser of embodiment 18, wherein the color shift of the light diffuser ranges from about -0.1 to about 0.1.

[0137] Embodiment 20 A display device, light source, 20. A light diffuser according to any one of embodiments 1 to 19, and an image display device having a plurality of pixels; Equipped with The display device, wherein the light diffuser is positioned between the light source and the image display device.

[0138] Embodiment 21 1. A method of manufacturing a light diffuser, comprising: Expressed as mole % on an oxide basis, 60-75 mol% SiO2, 2 to 9 mol% Al2O3, 17-25 mol% LiO, and 0.5 to 6 mol% Na2O+K2O, forming a mixture by melting together forming a ribbon from the mixture having a first major surface and a second major surface opposite the first major surface; and heating the ribbon to a crystallization temperature ranging from about 850°C to about 900°C for a crystallization time ranging from about 0.5 hours to about 6 hours; and heating the ribbon to the crystallization temperature results in the formation of a crystalline phase comprising lithium disilicate and one or more of beta-spodumene or beta-quartz having a median particle size ranging from about 500 nanometers to about 1,000 nanometers, the crystalline phase being dispersed throughout the volume of the light diffuser.

[0139] Embodiment 22 22. The method of claim 21, further comprising heating the ribbon to a nucleation temperature ranging from about 550°C to about 800°C for a nucleation time ranging from about 0.5 hours to about 6 hours before heating the ribbon to the crystallization temperature.

[0140] Embodiment 23 23. The method of claim 21 or 22, wherein forming the ribbon comprises rolling, slot drawing, or float drawing the mixture.

[0141] Embodiment 24 24. The method of any one of embodiments 21 to 23, wherein the mixture has a liquidus temperature ranging from about 1000°C to about 1250°C.

[0142] Embodiment 25 25. The method of any one of embodiments 21 to 24, wherein the mixture has a liquidus viscosity ranging from about 800 Pascal·seconds (Pa·s) to about 1,000 Pa·s.

[0143] Embodiment 26 26. The method of embodiment 25, wherein the liquidus viscosity ranges from about 140 Pa·s to about 600 Pa·s.

[0144] Embodiment 27 The mixture, expressed in mole percent on an oxide basis, comprises: 0.5 to 2 mol% P2O5, 0.2 to 8 mol% ZrO2, 0-5 mol% B2O3, 0-5 mol% MgO+CaO+SrO, 0-2 mol% ZnO, and 0-2 mol% SnO2, 27. The method of any one of embodiments 21 to 26, further comprising:

[0145] Embodiment 28 The mixture, expressed in mole percent on an oxide basis, comprises: 67-70 mol% SiO2, 2.5 to 4.5 mol% Al2O3, 21-24 mol% LiO, 0.5 to 2 mol% NaO, 0 to 1 mol% K2O, 1-2 mol% P2O5, 1.5 to 4 mole percent ZrO2, and 0.1 mol% SnO2, 28. The method of any one of embodiments 21 to 27, comprising:

[0146] Embodiment 29 29. The method of any one of embodiments 21 to 28, wherein beta-spodumene predominates.

[0147] Embodiment 30 29. The method of any one of embodiments 21 to 28, wherein beta-quartz predominates.

[0148] Embodiment 31 31. The method of any one of embodiments 21 to 30, wherein the median particle size ranges from about 600 nanometers to about 800 nanometers.

[0149] Embodiment 32 32. The method of any one of embodiments 21 to 31, wherein the lithium disilicate crystals are substantially connected.

[0150] Embodiment 33 33. The method of any one of claims 21 to 32, wherein the light diffuser has a light transmittance ranging from about 40% to about 70%.

[0151] Embodiment 34 34. The method of any one of claims 21 to 33, wherein the light diffuser has a haze of about 95% or greater.

[0152] Embodiment 35 35. The method of any one of claims 21 to 34, wherein the light diffuser has an integrated light transmittance of about 40% or greater.

[0153] Embodiment 36 36. The method of any one of claims 21 to 35, wherein the light diffuser has a hiding power of about 20 millimeters or less.

[0154] Embodiment 37 37. The method of any one of claims 21 to 36, wherein the light diffuser has a color shift of about 0.2 or less. [Explanation of symbols]

[0155] 101 Display device 103 Light Diffuser 105 Light source 107 Image display devices 109 users 111 first principal surface 113 Second main surface 115 Thickness 201, 301 Amorphous glass phase 203, 303 crystal

Claims

1. In the light diffuser, an amorphous phase, and a crystalline phase comprising lithium disilicate and one or more of beta-spodumene or beta-quartz having a median particle size ranging from 500 nanometers to 1,000 nanometers, the crystalline phase being dispersed throughout the volume of the light diffuser; Including, The light diffuser comprises, expressed as mole percent on an oxide basis: 60 mol % to 75 mol % SiO ２ , 2 mol% to 9 mol% Al ２ O ３ , 17 mol% to 25 mol% Li ２ O, and 0.5 mol% to 6 mol% Na ２ O+K ２ O. a light diffuser including:

2. Expressed in mole percent on an oxide basis, 0.5 mol % to 2 mol % P ２ O ５ , 0.2 mol% to 8 mol% ZrO ２ , 0 mol % to 5 mol % B ２ O ３ , 0 mol % to 5 mol % of MgO+CaO+SrO, 0 mol% to 2 mol% ZnO, and 0 mol% to 2 mol% SnO ２ , The light diffuser of claim 1 , further comprising:

3. The light diffuser comprises, expressed as mole percent on an oxide basis: 67 mol% to 70 mol% SiO ２ , 2.5 mol% to 4.5 mol% Al ２ O ３ , 21 mol% to 24 mol% Li ２ O. 0.5 mol% to 2 mol% Na ２ O. 0 mol % to 1 mol % K ２ O. 1 mol% to 2 mol% P ２ O ５ , 1.5 mol% to 4 mol% ZrO ２ , and 0.1 mol% SnO ２ , The light diffuser of claim 2 , comprising:

4. The light diffuser of claim 1 , wherein the light diffuser has a light transmittance ranging from 50% to 70% and a haze of 95% or greater.

5. The light diffuser of claim 1 , wherein the light diffuser has a haze of 95% or greater.

6. The light diffuser of claim 1 , wherein the light diffuser has an integrated light transmittance of 40% or greater.

7. The light diffuser of claim 1 , wherein the light diffuser has a hiding power of 20 millimeters or less.

8. The light diffuser of claim 1 , wherein the light diffuser has a color shift of 0.2 or less.

9. A display device, light source, A light diffuser according to any one of claims 1 to 8, and an image display device having a plurality of pixels; Equipped with The display device, wherein the light diffuser is positioned between the light source and the image display device.

10. 1. A method of manufacturing a light diffuser, comprising: Expressed in mole percent on an oxide basis, 60 mol % to 75 mol % SiO ２ , 2 mol% to 9 mol% Al ２ O ３ , 17 mol% to 25 mol% Li ２ O, and 0.5 mol% to 6 mol% Na ２ O+K ２ O. forming a mixture by melting together forming a ribbon from the mixture having a first major surface and a second major surface opposite the first major surface; heating the ribbon to a nucleation temperature ranging from 550°C to 800°C for a nucleation time ranging from 0.5 hours to 6 hours before heating the ribbon to a crystallization temperature; and heating the ribbon to a crystallization temperature ranging from 850°C to 900°C for a crystallization time ranging from 0.5 hours to 6 hours; and heating the ribbon to the crystallization temperature results in the formation of a crystalline phase comprising lithium disilicate and one or more of beta-spodumene or beta-quartz having a median particle size ranging from 500 nanometers to 1,000 nanometers, the crystalline phase being dispersed throughout the volume of the light diffuser.

11. The method of claim 10, wherein the mixture has a liquidus temperature ranging from 1000°C to 1250°C.

12. 11. The method of claim 10, wherein the mixture has a liquidus viscosity ranging from 80 Pascal-seconds (Pa·s) to 1,000 Pa·s.

13. The mixture, expressed in mole percent on an oxide basis, comprises: 0.5 mol % to 2 mol % P ２ O ５ , 0.2 mol% to 8 mol% ZrO ２ , 0 mol % to 5 mol % B ２ O ３ , 0 mol % to 5 mol % of MgO+CaO+SrO, 0 mol% to 2 mol% ZnO, and 0 mol% to 2 mol% SnO ２ , The method of claim 10 further comprising:

14. The mixture, expressed in mole percent on an oxide basis, comprises: 67 mol% to 70 mol% SiO ２ , 2.5 mol% to 4.5 mol% Al ２ O ３ , 21 mol% to 24 mol% Li ２ O. 0.5 mol% to 2 mol% Na ２ O. 0 mol % to 1 mol % K ２ O. 1 mol% to 2 mol% P ２ O ５ , 1.5 mol% to 4 mol% ZrO ２ , and 0.1 mol% SnO ２ , 11. The method of claim 10, comprising:

Images