Systems and methods for depositing phosphor-containing inks

Abstract

A phosphor ink composition and a system and method for depositing such phosphor-containing inks are disclosed. The ink composition according to the present disclosure comprises a compound represented by Formula 1, A x [MF y ]:Mn 4+ (I) Mn 4+ The phosphor material includes a doped phosphor and at least one binder material or solvent, and the phosphor material includes Mn 4+ The doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, the ink composition has a viscosity of greater than 2,000 cP to about 30,000 cP, A is Li, Na, K, Rb, Cs, or a combination thereof, M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof, and x is [MF y ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 338,428, filed May 4, 2022, for "PHOSPHORS, INK FORMULATIONS AND FILMS," U.S. Provisional Patent Application No. 63 / 338,868, filed May 5, 2022, for "PRINTING, FILMS AND SUBSTRATES," U.S. Provisional Patent Application No. 63 / 453,396, filed March 20, 2023, for "PHOSPHOR CONVERTED MICROLED ARRAY WITH REFLECTIVE LAYER FOR A TRANSPARENT DISPLAY ARCHITECTURE," and U.S. Provisional Patent Application No. 63 / 498,414, filed April 26, 2023, for "PHOSPHOR INK PRINTED COLOR FILTER PARTS," all of which are incorporated herein by reference in their entireties. [Background technology]

[0002] The subject matter described herein generally relates to depositing inks containing phosphor materials for lighting and display applications.

[0003] Narrow-band phosphor materials achieve high color quality in LED-based lighting and displays. Next-generation displays will feature 10,000 μm wavelengths that can produce light visible to the human eye at very low drive currents. 2 They may incorporate mini and micro LEDs with active areas of approximately 100 μm to 0.7 mm. In the case of micro LEDs, the display may be self-emissive or may include a miniature backlight and be arrayed with individual LEDs less than 100 μm in size.

[0004] To realize the full potential of mini-LED and micro-LED technology, new methods for applying phosphor materials to miniaturized, micrometer-sized LED elements must be developed. Coating and printing films, such as inkjet printing, spin coating, or slot-die coating of phosphor materials, have been developed to prepare LEDs, including miniature LEDs.

[0005] Inkjet printable inks have been prepared using quantum dots. Quantum dot materials have nanometer particle sizes with strong absorption coefficients. Quantum dots suffer from low quantum efficiency (QE) and poor thermal stability, which significantly limit their practical applications.

[0006] Phosphors have improved properties compared to quantum dot materials. Phosphors for use with compact LEDs must be correspondingly small. Printing and coating compositions require stable dispersions, and phosphor materials with common organic solvents can cause undesirable settling or phase separation for subsequent coating and printing processes. Phosphor materials with small particle sizes also tend to aggregate when mixed with commonly used solvents, making them unsuitable for ink compositions or formulations. Summary of the Invention [Means for solving the problem]

[0007] In one embodiment, an ink composition is provided, the ink composition comprising Mn 4+ The phosphor material includes a doped phosphor and at least one binder material or solvent, and the phosphor material includes Mn 4+ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of greater than 2000 cP to about 30,000 cP; A x [MF y ]:Mn 4+ I wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is [MF y ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

[0008] In another embodiment, a method for inkjet printing, flexographic printing, or microdispensing printing is disclosed. The method includes printing an ink composition, the ink composition comprising Mn 4+ The ink composition includes a low viscosity ink composition including a phosphor material containing a doped phosphor and at least one binder material or solvent, and the ink composition includes a Mn 4+ the doped phosphor has a D50 particle size of about 0.5 microns to about 5 microns, and the ink composition has a viscosity of about 10 cP to about 1000 cP; A x [MF y ]:Mn 4+ I wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is [MF y ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

[0009] In another embodiment, a method for screen printing, direct write printing, aerosol jet printing, gravure printing, or flexographic printing, or microdispensing printing, the method includes printing an ink composition, the ink composition comprising a Mn 4+ The ink composition includes a medium viscosity ink composition including a phosphor material including a doped phosphor and at least one binder material or solvent, and the ink composition includes a Mn 4+ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of about 1000 cP to about 10,000 cP; A x [MF y ]:Mn 4+ I wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is [MF y ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

[0010] In another embodiment, a method for direct-write printing or extrusion is disclosed. The method includes printing or extruding an ink composition, the ink composition comprising a Mn 4+ The ink composition includes a phosphor material containing a doped phosphor and at least one binder material or solvent, and the ink composition includes a Mn 4+ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of about 10,000 cP to about 30,000 cP; A x [MF y ]:Mn 4+ I wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is [MF y ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

[0011] In another embodiment, Mn of Formula 1 4+ A device comprising an LED light source optically coupled and / or radiatively coupled to a phosphor composition comprising a phosphor material including a doped phosphor, wherein the phosphor material is Mn 4+ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the phosphor composition combined with the LED light source has an aspect ratio of at least 0.1; A x [MF y ]:Mn 4+ I wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is [MF y ] is the absolute value of the charge of the ion, and y is 5, 6, or 7. The term "aspect ratio," as used herein, refers to the ratio of the width of an object to the height of the object. Thus, in some embodiments, the ratio of the width of the phosphor composition to the height of the phosphor composition is 1:10 or 0.1:F.

[0012] In another embodiment, a color filter component is disclosed. The color filter component includes a well, a first ink phosphor composition, and a second ink phosphor composition, the first ink being a phosphor material. phosphor the first ink phosphor composition comprises a high refractive index and the second ink phosphor composition comprises a low refractive index, the second ink phosphor composition is disposed proximate to a surface on which excitation light is incident, and the first ink phosphor composition and the second ink phosphor composition comprise an Mn 4+ The phosphor material includes a doped phosphor and at least one binder material or solvent, and the phosphor material includes Mn 4+ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of about 10,000 cP to about 30,000 cP; A x [MF y ]:Mn 4+ I wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is [MF y ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

[0013] In another embodiment, a method includes depositing a first ink composition into wells of a color filter component, and subsequently depositing a second ink composition into the wells of the color filter component, wherein the first ink composition has a high refractive index and the second ink composition has a low refractive index, the second ink composition being disposed proximate to a surface on which excitation light is incident, and wherein the first ink phosphor composition and the second ink composition are selected from the group consisting of Mn 4+The phosphor material includes a doped phosphor and at least one binder material or solvent, and the phosphor material includes Mn 4+ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of about 10,000 cP to about 30,000 cP; A x [MF y ]:Mn 4+ I wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is [MF y ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

[0014] In another embodiment, a light-emitting array is disclosed, the light-emitting array including a plurality of micro LEDs, each micro LED enclosed within a bank or well structure, the bank or well structure configured to contain an ink composition deposited within the bank or well structure, the ink composition comprising a Mn 4+ The phosphor material includes a doped phosphor and at least one binder material or solvent, and the phosphor material includes Mn 4+ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of about 10,000 cP to about 30,000 cP; A x [MF y ]:Mn 4+ I wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is [MF y ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

[0015] In another embodiment, a transparent display is disclosed, the transparent display comprising a micro LED array coated with a phosphor composition, the transparent display having a transparency of at least 50%, the phosphor composition comprising Mn 4+ Doped phosphor containing Mn 4+ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the phosphor composition has an aspect ratio of at least 0.1; A x [MF y ]:Mn 4+ I wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is [MF y ] is the absolute value of the charge of the ion, and y is 5, 6, or 7. [Brief explanation of the drawings]

[0016] These and other features, aspects, and advantages of the present disclosure will be better understood from the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts throughout.

[0017] [Figure 1A] 1 is a schematic cross-sectional view of a device according to one embodiment of the present disclosure. [Figure 1B] 1 is a schematic cross-sectional view of a device according to an exemplary embodiment. [Figure 1C] 1 is a schematic cross-sectional view of a device according to an exemplary embodiment. [Figure 1D] 1 is a schematic cross-sectional view of a device according to an exemplary embodiment. [Figure 1E] 1 is a schematic cross-sectional view of a device according to an exemplary embodiment. [Figure 2] 1 is a schematic cross-sectional view of a lighting device according to an embodiment of the present disclosure. [Figure 3] FIG. 10 is a schematic cross-sectional view of a lighting device according to another embodiment of the present disclosure. [Figure 4]FIG. 1 is a cutaway side perspective view of a lighting device according to one embodiment of the present disclosure. [Figure 5A] FIG. 1 is a schematic perspective view of a surface mounted device (SMD) according to one embodiment of the present disclosure. [Figure 5B] 1 is a schematic cross-sectional view of an SMD according to an exemplary embodiment. [Figure 5C] 1 is a schematic cross-sectional view of a device according to an exemplary embodiment. [Figure 6] FIG. 1 is a schematic diagram of a contact stencil printing system according to one embodiment of the present disclosure. [Figure 7] FIG. 1 is a schematic diagram of a snap-off stencil printing system according to one embodiment of the present disclosure. [Figure 8A] FIG. 1 is a schematic diagram of a print well configuration according to one embodiment of the present disclosure. [Figure 8B] FIG. 1 is a schematic diagram of a print well configuration according to one embodiment of the present disclosure. [Figure 8C] FIG. 1 is a schematic diagram of a print well configuration according to one embodiment of the present disclosure. [Figure 8D] FIG. 1 is a schematic diagram of a print well configuration according to one embodiment of the present disclosure. [Figure 9] FIG. 1 is a schematic diagram of a bank configuration according to one embodiment of the present disclosure. [Figure 10] FIG. 7 is a diagram of a composition deposited on a substrate using the contact stencil printing system of FIG. 6. [Figure 11] FIG. 8 is a diagram of a composition deposited on a substrate using the snap-off stencil printing system of FIG. 7. [Figure 12A] 1 is a graph depicting the aspect ratio of printed ink composition patterns deposited using snap-off stencil printing according to one embodiment of the present disclosure. [Figure 12B] 1 is a graph depicting the aspect ratio of printed ink composition patterns deposited using snap-off stencil printing according to one embodiment of the present disclosure. [Figure 12C] 1 is a graph depicting the aspect ratio of printed ink composition patterns deposited using snap-off stencil printing according to one embodiment of the present disclosure. [Figure 12D] 1 is a graph depicting the aspect ratio of printed ink composition patterns deposited using snap-off stencil printing according to one embodiment of the present disclosure. [Figure 13A] 1 is a printed ink composition pattern deposited by snap-off stencil printing. [Figure 13B] FIG. 13B is a photoluminescence intensity map of the pattern of FIG. 13A. [Figure 14A] FIG. 1 is a schematic diagram of a high-precision pick and place system according to one embodiment of the present disclosure. [Figure 14B] FIG. 1 is a schematic diagram of a high-precision pick and place system according to one embodiment of the present disclosure. [Figure 15] 1 is a dip coating system according to one embodiment of the present disclosure. [Figure 16A] FIG. 2 is a top view of an exemplary red-green-blue (RGB) pixel according to one embodiment of the present disclosure. [Figure 16B] FIG. 2 is a side view of an exemplary red-green-blue (RGB) pixel according to one embodiment of the present disclosure. [Figure 17] 10 is a graph comparing red emission from a color filter assembly having a KSF phosphor-filled red sub-pixel depth of 8 μm versus a depth of 16 μm, according to one embodiment of the present disclosure. [Figure 18] FIG. 1 shows photoluminescence mapping of a blank substrate. [Figure 19] FIG. 10 shows photoluminescence mapping of a KSF-filled red sub-pixel. [Figure 20] 1 is a graph showing percent external quantum efficiency (EQE). [Figure 21] FIG. 1 is a schematic diagram of a hybrid conductive grid according to one embodiment of the present disclosure. [Figure 22] 1 is a color point contour plot of an exemplary LED array.

[0018] Unless otherwise indicated, the drawings provided herein are intended to illustrate features of embodiments of the present disclosure. These features are believed to be applicable to a wide variety of systems incorporating one or more embodiments of the present disclosure. Thus, the drawings are not intended to include all conventional features known to those skilled in the art that are required to practice the embodiments disclosed herein. DETAILED DESCRIPTION OF THE INVENTION

[0019] In the following specification and claims, reference will be made to a number of terms that shall be defined to have the following meanings.

[0020] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. As used herein, the term "or" is not intended to be exclusive and refers to the presence of at least one of the referenced components, and includes cases where combinations of the referenced components may be present, unless the context clearly dictates otherwise.

[0021] As used herein throughout the specification and claims, approximation language may be applied to modify any quantitative expression that may vary permissibly without resulting in a change in the basic function involved. Thus, values ​​modified with terms such as "about," "substantially," and "approximately" are not limited to the exact value specified. In at least some instances, approximation language may correspond to the precision of the instrument used to measure the value. Here, and throughout the specification and claims, range limitations may be combined and / or interchanged, and such ranges are identified and include all subranges contained therein, unless the context or language dictates otherwise.

[0022] "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, or the subsequently specified material may or may not be present, and that the description includes instances where the event or circumstance occurs or the material is present, and instances where the event or circumstance does not occur or the material is not present.

[0023] The brackets in the formula indicate that at least one of the elements is present in the phosphor material, and any combination of two or more of them may be present. For example, the formula [Ca,Sr,Ba]MgSiO:Eu 2+ ,Mn 2+ contains at least one of Ca, Sr, or Ba, or any combination of two or more of Ca, Sr, or Ba. Examples include CaMgSiO:Eu 2+ .Mn 2+ , Sr3MgSi2O8:Eu 2+ .Mn 2+ , or Ba3MgSi2O8:Eu 2+ .Mn 2+ Formulas that include an activator after a colon (:) indicate that the phosphor material is doped with the activator. Formulas that include two or more activators separated by a comma (,) after a colon (:) indicate that the phosphor material is doped with one or both of the activators. For example, the formula [Ca,Sr,Ba]3MgSi2O8:Eu 2+ ,Mn 2+ is [Ca,Sr,Ba]3MgSi2O8:Eu 2+ , [Ca,Sr,Ba]3MgSi2O8:Mn 2+ , or [Ca,Sr,Ba]3MgSi2O8:Eu 2+ and Mn 2+ Includes.

[0024] In one embodiment, an ink composition is provided. The ink composition comprises an Mn 4+ The phosphor material includes a doped phosphor and at least one binder material or solvent, and the phosphor material includes Mn 4+the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of greater than 2000 cP to about 30,000 cP; A x [MF y ]:Mn 4+ I wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is [MF y ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

[0025] The ink composition can be tailored to a particular printing application. For example, the ink composition can be used in inkjet printing, flexographic or microdispensing printing, screen printing, direct write printing, aerosol jet printing, gravure printing, etc. etc. The ink compositions may be tailored for any one of the following printing applications: inkjet printing, flexographic printing, and / or microdispensing printing; ink compositions may be tailored for extrusion; for example, low-viscosity ink compositions may be tailored for inkjet printing, flexographic printing, and / or microdispensing printing; medium-viscosity inks may be tailored for screen printing, direct-write printing, aerosol jet printing, gravure printing, flexographic printing, and / or microdispensing printing; and high-viscosity inks may be tailored for high-viscosity screen printing, direct-write printing, and / or extrusion.

[0026] The ink composition includes a phosphor material, the type, amount, and size of which are determined by the optical application, specifically the color point and optical density.

[0027] The phosphor material may be present in the ink composition at about 5% to about 70% by weight. In another embodiment, the phosphor material is present at about 30% to about 60% by weight. In another embodiment, the phosphor material is present at about 10% to about 50% by weight. The weight percent of the phosphor material is based on the total weight of the ink composition.

[0028] Mn in Formula I 4+ Doped phosphors are complex fluoride materials or coordination compounds that contain at least one coordination center surrounded by fluoride ions that act as ligands, and are optionally charge compensated by counterions. For example, K2SiF6:Mn 4+ In the case of activator ions (Mn 4+ ) also act as coordination centers, substituting some of the centers of the host lattice, e.g., Si. The host lattice (including counterions) can further modify the excitation and emission properties of the activator ions.

[0029] In certain embodiments, the coordination center of the phosphor, i.e., M in Formula I, is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof. More specifically, the coordination center may be Si, Ge, Ti, or a combination thereof. The counterion, or A in Formula I, may be Li, Na, K, Rb, Cs, or a combination thereof, more specifically K or Na. An example of a phosphor of Formula I is K2[SiF6]:Mn 4+ , K2[TiF6]:Mn 4+ , K2[SnF6]:Mn 4+ , Cs2[TiF6]:Mn 4+ , K2[GeF6]Mn 4+ , Rb2[TiF6]Mn 4+ , Cs2[SiF6]:Mn 4+ , Rb2[SiF6]:Mn 4+ , Na2[SiF6]:Mn 4+ , Na2[TiF6]:Mn 4+ , Na2[ZrF6]:Mn 4+ , K3[ZrF7]:Mn 4+ , K3[BiF6]K3[YF6]:Mn 4+ , K3[LaF6]:Mn 4+ , K3[GdF6]:Mn 4+ , K3[NbF7]:Mn 4+ , K3[TaF7]:Mn 4+ In certain embodiments, the phosphor of Formula I is K2SiF6:Mn 4+(PFS) or Na2[SiF6]:Mn 4+ (NSF).

[0030] Mn 4+ The incorporation of the activator Mn into the doped phosphor (referred to as Mn%) improves color conversion. Increasing the incorporation level improves color conversion by increasing the intensity of the red emission, maximizing the absorption of the exciting blue light, and reducing the amount of unconverted blue light or blue light spillover from the blue LED.

[0031] In one embodiment, red-emitting Mn 4+ The doped phosphor has a Mn loading or Mn % of at least 1 wt%. In another embodiment, the red-emitting phosphor has a Mn loading of at least 1.5 wt%. In another embodiment, the red-emitting phosphor has a Mn loading of at least 2 wt%. In another embodiment, the red-emitting phosphor has a Mn % of at least 3 wt%. In another embodiment, the Mn % is greater than 3.0 wt%. In another embodiment, the Mn content in the red-emitting phosphor is from about 1 wt% to about 4 wt%. In another embodiment, the red-emitting phosphor has a Mn % of from about 2 wt% to about 5 wt%.

[0032] In one embodiment, Mn 4+ The doped phosphor is K2SiF6:Mn 4+ The red-emitting phosphor may be a manganese-doped potassium fluorosilicate such as (PFS). PFS has a narrowband emission with multiple peaks with an average full width at half maximum (FWHM) of less than 4 nm. In another embodiment, the red-emitting phosphor is Na2SiF6:Mn 4+ (NFS) is also acceptable.

[0033] In one embodiment, Mn 4+ The doped phosphor may be further treated, such as by annealing, washing, roasting, or any combination of these treatments. 4+Post-treatment processes for doped phosphors are described in U.S. Patent Nos. 8,906,724, 8,252,613, 9,698,314, U.S. Patent Application Publication Nos. 2016 / 0244663, 2018 / 0163126, and 2020 / 0369956, the entire contents of each of which are incorporated herein by reference. In one embodiment, Mn 4+ The doped phosphor can be annealed, treated with multiple cleaning processes, and roasted.

[0034] To improve reliability, Mn in formula I 4+ The doped phosphor can be at least partially coated with a surface coating to increase the stability of the phosphor particles, to modify the particle surface to prevent agglomeration, and to improve the zeta potential of the particles. In one embodiment, the surface coating can be a metal fluoride, silica, or organic coating. In one embodiment, Mn 4+ A red-emitting phosphor based on a phosphor-activated complex fluoride material is at least partially coated with a metal fluoride to increase the positive zeta potential and reduce agglomeration. In one embodiment, the metal fluoride coating comprises MgF2, CaF2, SrF2, BaF2, AgF, ZnF2, AlF3, or a combination thereof. In another embodiment, the metal fluoride coating is present in an amount of about 0.1% to about 10% by weight. In another embodiment, the metal fluoride coating is present in an amount of about 0.1% to about 5% by weight. In another embodiment, the metal fluoride coating is present in an amount of about 0.3% to about 3% by weight. Mn 4+ A metal fluoride coated red-emitting phosphor based on a complex fluoride material activated by The entire contents of each are incorporated herein by reference. Prepared as described in WO 2018 / 093832, U.S. Patent Application Publication No. 2018 / 0163126 and U.S. Patent Application Publication No. 2020 / 0369956.

[0035] The phosphor material may include an additional phosphor, such as an yttrium aluminum garnet phosphor (YAG). The powder ratio (YAG:PFS) can be adjusted to achieve a desired color point. The phosphor material may include an additional phosphor, such as a rare earth garnet phosphor. Rare earth elements include Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. In one embodiment, the rare earth garnet phosphor is an yttrium aluminum garnet phosphor (YAG). The ratio of the rare earth garnet phosphor to the Mn4+-doped phosphor can be adjusted to achieve a desired color point.

[0036] The ink composition comprises at least one binder material or at least one solvent. In some embodiments, the ink composition comprises a binder material and a solvent.

[0037] The ink composition may include a binder material to further optimize the ink properties. A wide variety of binder and resin systems with different chemistries and viscosities can be used.

[0038] In one embodiment, the binder matrix comprises a crosslinked polymer. In another embodiment, the binder material comprises a curable material, such as a photocurable or UV curable material, or a thermosetting or heat-curable binder material, or a combination thereof. The thermosetting or heat-curable binder material polymerizes or crosslinks to form a cured resin binder matrix. Exemplary heat-curable and UV binder materials include epoxy, acrylate, methacrylate, vinyl ester, and siloxane families. Examples of suitable commercially available resin systems include, but are not limited to, Pixelligent UVG Curable Ink Base, Optical Adhesive (Norland 68T), and Pixelligent PixJet SFZ-1, which contains 40 wt. % ZrO2 in an acrylic formulation.

[0039] In one embodiment, the binder material may be present in an amount of up to about 75% by weight. In another embodiment, the binder may be present in an amount of up to about 70% by weight. In another embodiment, the binder may be present in an amount of from about 5% to about 75% by weight. In another embodiment, the binder is present in an amount of from about 10% to about 70% by weight. In another embodiment, the binder is present in an amount of from about 20% to about 50% by weight. The weight percentages are based on the total weight of the ink composition.

[0040] In another embodiment, the ink composition includes a first polymerization initiator and a second polymerization initiator for a two-stage curing process, initiated by radiation wavelengths less than 400 nm during the first curing step of a photoinitiated polymerization process (UV curing). The first polymerization initiator decomposes faster than the second polymerization initiator. The second curing process does not include UV radiation, and the second polymerization initiator decomposes faster than the first polymerization initiator. After curing, the phosphor treatment concentration increases by 5%, preferably 10%, and the printed material shrinks in volume by less than 20%, preferably less than 15%. The overall print volume shrinkage does not exceed 20% by volume. The ink composition may contain a solvent. The amount of solvent, the polarity of the solvent, and the vapor pressure of the solvent can help create a stable ink that meets the viscosity, wetting, and optical density criteria of the ink composition. The solvent may be present in an amount effective to dissolve the phosphor material and any binder materials and adjust the ink composition to the desired viscosity. In one embodiment, the solvent may be present from about 5% to about 95% by weight. In another embodiment, the solvent may be present from about 10% to about 75% by weight. In another embodiment, the solvent is present from about 20% to about 50% by weight. The weight percent of the solvent is based on the weight of the ink composition.

[0041] Phosphor particles can be formulated into inks using several solvent systems that have proven useful in the printing industry. Suitable solvents have boiling points and polarities that are compatible with the desired printing application and do not interact significantly with the binder material or phosphor used.

[0042] The solvent may be polar or non-polar.Examples of solvents include, but are not limited to, acetone, glycol ethers such as diethylene glycol methyl ether, propylene methyl acrylate such as propylene glycol dimethyl acrylate, cyclic aromatic solvents such as toluene, xylene and anisole, aliphatic solvents such as hexane and tetradecane, alcohols such as ethanol, isopropanol and octanol, glycols such as ethylene glycol and propylene glycol, terpineol, acetates such as butyl acetate, propylene glycol methyl ether acetate (PGMEA), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), diethylene glycol methyl ether (DGME) and 2-(2-butoxyethoxy)ethyl acetate (BEA).

[0043] Co-solvents and solvent mixtures can also be used to improve fluidity, printing process, and film-forming properties. Solvent mixtures can be composed of any two or more of the solvents listed above, or can be composed of one of the above solvents with the addition of a small amount of a common organic solvent.

[0044] The ink composition includes a phosphor material having a D50 particle size in the range of about 0.5 to about 15 microns. The particle size must be small for ink composition preparation, printing, and film formation. In another embodiment, the phosphor material includes a D50 particle size in the range of about 0.5 microns to about 10 microns. In another embodiment, the D50 particle size is in the range of about 0.5 microns to about 5 microns.

[0045] D50(D 50 D90 or D 90 is the particle size of the volume distribution that is larger than the particle size of 90% of the particles in the distribution. D10 or D 10is the particle size of a volume distribution larger than the size of 10% of the particles in the distribution. The particle size of phosphors can be conveniently measured by laser diffraction or optical microscopy, and commercially available software can generate particle size distributions and spans. Span is a measure of the width of the particle size distribution curve of a granular material or powder and is defined according to the following equation: JPEG2025530884000047.jpg2582, D 90 , D 10 and D 50 is defined above. For phosphor particles, the span of the particle size distribution is not necessarily limited and may be ≦1.0 in some embodiments.

[0046] The ink composition has a viscosity of from about 10 cP to about 30,000 cP, hi another embodiment, the viscosity is from about 1000 cP to about 30,000 cP.

[0047] In some embodiments, the ink composition is a low-viscosity ink composition. Low-viscosity ink compositions include those with viscosities ranging from about 10 cP to about 1000 cP. In another embodiment, the low-viscosity ink composition has a viscosity ranging from about 10 cP to less than 1000 cP. Because low-viscosity ink compositions can be prone to particle settling, it is desirable to include phosphor material with very small particle size. Low-viscosity ink compositions can be used in printing applications such as bank or well structures.

[0048] In one embodiment, the ink composition is a medium viscosity ink composition. Medium viscosity ink compositions include those with a viscosity ranging from about 1000 cP to about 10,000 cP. In another embodiment, the viscosity ranges from greater than 1000 cP to less than 10,000 cP.

[0049] In one embodiment, the ink composition is a high viscosity ink composition. High viscosity ink compositions include those with viscosities ranging from about 10,000 cP to about 30,000 cP. In another embodiment, the viscosity ranges from greater than 10,000 cP to about 30,000 cP.

[0050] The viscosity ranges are relative to the starting viscosity range of the ink composition.

[0051] Additional additives may be added to the ink composition to further adjust ink or film properties such as adhesion or cohesion, light scattering, evaporation rate, stability, shelf life, and the like.

[0052] In one embodiment, the ink composition includes a scattering aid such as ZrO2 nanoparticles. Examples of scattering particles include, but are not limited to, titanium dioxide, aluminum oxide (Al2O3), zirconium oxide, indium tin oxide, cerium oxide, tantalum oxide, zinc oxide, magnesium fluoride (MgF2), calcium fluoride (CaF2), strontium fluoride (SrF2), barium fluoride (BaF2), silver fluoride (AgF), aluminum fluoride (AlF3), or combinations thereof. In other embodiments, additional additives such as pentaerythritol tetrakis(3-mercaptopropionate) from Bruno Bock (BB PTh) improve film quality.

[0053] The additive may be added to the ink composition in an amount of about 5% to about 20% by weight, based on the weight of the ink composition.

[0054] External heating may be used to improve the flow of the ink composition, but note that temperatures above 65°C for extended periods of time may lead to premature curing.

[0055] The ink compositions are prepared using a solvent-based mixing and stripping technique.

[0056] The phosphor and solvent or binder material are mixed until the phosphor is dispersed in the solvent and the solvent is partially removed. In some embodiments, the solvent is optional. Typically, the base ink, additives, and a small amount of solvent are mixed together, and then the phosphor material is added in 2-4 additions, mixing between additions. Additional solvent may be required to achieve the desired viscosity for good dispersion and coating.

[0057] When multiple phosphors are present, such as YAG, the second phosphor is added first, followed by Mn 4+ The fluorophore may be added in approximately 2 g increments. In one embodiment, the solution is shaken between each powder addition. For example, the solution may be shaken for 1 minute after each sample. In another embodiment, the mixture may be horn sonicated.

[0058] Once the particles are properly dispersed and homogenized, the solvent is partially removed. This process allows for high particle loading and allows the end user to control viscosity by how much solvent remains in the final formulation.

[0059] In one embodiment, the suspension is subjected to rotary evaporation until a desired amount of solvent is removed.

[0060] The ink solution can be cured after application by the printing techniques described herein. The ink solution can also be coated onto a substrate or formed into a film. In one embodiment, the ink composition is exposed to a suitable temperature for thermal curing or a suitable radiation wavelength for UV curing, such as less than 400 nm.

[0061] In one embodiment, a two-step cure using UV and thermal curing is applied to the ink composition. This system simultaneously contains both photosensitive and thermally sensitive groups. The first curing process utilizes UV curing to soft-cure the material in place. The wavelength for initiating polymerization is less than 400 nm (to be classified as UV curing). The second curing step is a thermal cure, which uses heat to initiate the remainder of the polymerization reaction. The second curing step acts as a bonding or full cure mechanism. In films, the second step can reduce the volume of the deposited film by shrinkage.

[0062] The advantage of a two-stage curing approach to film curing is the ability to tailor the amount of shrinkage of the deposited film at any point in the process. Depending on the initiator content, the PFS concentration can be adjusted to change the film's densification mechanism. UV-only curing systems rely on UV radiation hitting every surface and cannot anticipate curing in shadowed or deep areas. Heat-only curing is typically not fast enough and can result in "slumping" or separation / skinning of the deposited ink. It can be envisioned that UV curing can be used to "soft cure" a feature or film, followed by a thermal cure to "hard cure" the feature or film.

[0063] A two-step curing technique can also be used to form one feature on top of another cured feature by UV curing, followed by a thermal cure to further "bond" the two layers together.

[0064] The phosphor material may contain one or more other luminescent materials. Additional luminescent materials, such as blue, yellow, red, orange, or other colored phosphors, can be used in the phosphor material to customize the white color of the resulting light and to produce specific spectral output distributions.

[0065] Phosphors suitable for use in the phosphor material include, but are not limited to, (Sr 1-z [Ca,Ba,Mg,Zn] z ) 1-(x+w) [Li,Na,K,Rb] w Ce x )3(Al 1-y Si y )O 4+y+3(x-w) F 1-y-3(x-w) , 0 <x≦0.10、0≦y≦0.5、0≦z≦0.5、0≦w≦x;[Ca,Ce]3Sc2Si3O 12 (CaSiG);[Sr,Ca,Ba]3Al 1-x Si x O 4+x F 1-x :Ce 3+(SASOF)); [Ba, Sr, Ca]5(PO4)3[Cl, F, Br, OH]:Eu 2+ , Mn 2+ ; [Ba, Sr, Ca]BPO5:Eu 2+ , Mn 2+ ; [Sr, Ca] 10 (PO4)6*vB2O3:Eu 2+ (where 0 < v ≦ 1); Sr2Si3O8*2SrCl2:Eu 2+ ; [Ca, Sr, Ba]3MgSi2O8:Eu 2+ , Mn 2+ ; BaAl8O 13 : Eu 2+ ; 2SrO*0.84P2O5*0.16B2O3:Eu 2+ ; [Ba, Sr, Ca]MgAl 10 O 17 : Eu 2+ , Mn 2+ ; [Ba, Sr, Ca]Al2O4:Eu 2+ ; [Y, Gd, Lu, Sc, La]BO3:Ce 3+ , Tb 3+ ; ZnS:Cu + , Cl - ; ZnS:Cu + , Al 3+ ; ZnS:Ag + , Cl - ; ZnS:Ag + , Al<00001�7>; [Ba, Sr, Ca]2Si 1-n O 4-2n [[ID=​​​​​​​​​​​​​​​​​​​​2+ , Mn 2+ ; [Gd, Y, Lu, La]2O3: Eu 3+ , Bi 3+ ; [Gd, Y, Lu, La]2O2S: Eu 3+ , Bi 3+ ; [Gd, Y, Lu, La]VO4: Eu 3+ , Bi 3+ ; [Ca, Sr, Mg]S: Eu 2+ , Ce 3+ ; SrY2S4: Eu 2+ ; CaLa2S4: Ce 3+ ; [Ba, Sr, Ca]MgP2O7: Eu 2+ , Mn 2+ ; [Y, Lu]2WO6: Eu 3+ , Mo 6+ ; [Ba, Sr, Ca] b Si g N m : Eu 2+ (where 2b + 4g = 3m); Ca3(SiO4)Cl2: Eu 2+ ; [Lu, Sc, Y, Tb] 2-u-v Ce v Ca 1+u Li w Mg 2-w P<000019​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​1+c Si 1-c N3, (0≦c≦0.2, 0≦f≦0.2);Ca 1-h-r Ce h EU r Al 1-h (Mg, Zn) h SiN3, (0≦h≦0.2, 0≦r≦0.2);Ca 1-2s-t Ce s [Li,Na] s EU t AlSiN3, (where 0≦s≦0.2, 0≦t≦0.2, s+t>0); [Sr, Ca]AlSiN3; and Eu 2+ ,Ce 3+ , Li2CaSiO4:Eu 2+ Includes:

[0066] In certain embodiments, the additional phosphor is [Y,Gd,Lu,Tb]3[Al,Ga]5O 12 :Ce 3+ , β-SiAlON:Eu 2+ , [Sr,Ca,Ba][Ga,Al]2S4:Eu 2+ , [Li,Ca]α-SiAlON:Eu 2+ , [Ba,Sr,Ca]2Si5N8:Eu 2+ , [Ca,Sr]AlSiN3:Eu 2+ , [Ba,Sr,Ca]LiAl3N4:Eu 2+ , [Sr,Ca,Mg]S:Eu 2+ , and [Ba,Sr,Ca]2Si2O4:Eu 2+ Examples include:

[0067] The phosphor material can include at least one green-emitting phosphor. The green-emitting phosphor can include any suitable green-emitting phosphor, including uranium phosphors. In one embodiment, the green-emitting uranium phosphor includes, but is not limited to, Ba3(PO4)2(UO2)2P2O7, Ba3(PO4)2(UO2)2V2O7, gamma-Ba2UO2(PO4)2, BaMgUO2(PO4)2, BaZnUO2(PO4)2, Na2UO2P2O7, K2UO2P2O7, Rb2UO2P2O7, Cs2UO2P2O7, K4UO2(PO4)2, K4UO2(VO4)2, or NaUO2P3O9, as described in U.S. Pat. No. 11,254,864 and incorporated herein.

[0068] Other additional light-emitting materials suitable for use in the ink composition can include electroluminescent polymers such as polyfluorenes, preferably poly(9,9-dioctylfluorene) and its copolymers, such as poly(9,9'-dioctylfluorene-co-bis-N,N'-(4-butylphenyl)diphenylamine) (F8-TFB); poly(vinylcarbazole) and polyphenylenevinylene and their derivatives. Additionally, the light-emitting layer may include blue, yellow, orange, green, or red phosphorescent dyes, or metal complexes, quantum dot materials, or combinations thereof. Materials suitable for use as phosphorescent dyes include, but are not limited to, tris(1-phenylisoquinoline)iridium(III) (red dye), tris(2-phenylpyridine)iridium (green dye), and iridium(III) bis(2-(4,6-difluorenephenyl)pyridinato-N,C2) (blue dye). Fluorescent and phosphorescent metal complexes commercially available from ADS (American Dyes Source) can also be used. ADS green dyes include ADS060GE, ADS061GE, ADS063GE, and ADS066GE, ADS078GE, and ADS090GE. ADS blue dyes include ADS064BE, ADS065BE, and ADS070BE. ADS red dyes include ADS067RE, ADS068RE, ADS069RE, ADS075RE, ADS076RE, ADS067RE, and ADS077RE.

[0069] Exemplary QD materials are II-IV compound semiconductors such as CdS, CdSe, CdS / ZnS, CdSe / ZnS or CdSe / CdS / ZnS, CdTe, ZnSe, ZnTe, ZnS, HgTe, HgS, HgSe, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, II-VI group compound semiconductors such as CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, GaN, GaP, GaNP, GaNAs, GaPAs, GaAs, GaAlNP, GaAlNAs, GaInNP, These include, but are not limited to, III-V or IV-VI compound semiconductors such as GaInNAs, GaInPAs, AlN, AlNP, AlNAs, AlP, AlPAs, AlAs, InN, InNP, InP, InNAs, InPAs, InAS, InAlNP, InAlNAs, InAlPAs, PbS / ZnS or PbSe / ZnS, Group IV semiconductors such as Si, Ge, SiC and SiGe, chalcopyrite-type compounds including, but not limited to, CuInS2, CuInSe2, CuGaS2, CuGaSe2, AgInS2, AgInSe2, AgGaS2, AgGaSe2, or perovskite QDs having the formula ABX3 (where A is cesium, methylammonium or formamidinium, B is lead or tin, and C is chloride, bromide or iodide). The quantum dot material can include a core-shell nanostructure having an Ag-In-Ga-S (AIGS) core and an Ag-Ga-S (AGS) shell.

[0070] In one embodiment, the perovskite quantum dots may be CsPbX3, where X is Cl, Br, I, or a combination thereof. The average size of the QD material may range from about 2 nm to about 20 nm. The surface of the QD particles may be further modified with ligands such as amine ligands, phosphine ligands, phosphatides, and polyvinylpyridines. In one aspect, a red phosphor may be the quantum dot material.

[0071] All semiconductor quantum dots may also have a suitable shell or coating for passivation and / or environmental protection. The QD material may be a core / shell QD, comprising a core, at least one shell coated on the core, and an outer coating containing one or more ligands, preferably organic polymeric ligands. Exemplary materials for preparing core-shell QDs include Si, Ge, Sn, Se, Te, B, C (including diamond), P, Co, Au, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, ZnO, ZnS, ZnSe, ZnTe, CdS, and CdSe. , CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, MnS, MnSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si3N4, Ge3N4, Al2O3, [Al,Ga,In]2, [S,Se,Te]3, and suitable combinations of two or more such materials. Exemplary core-shell luminescent nanocrystals include, but are not limited to, CdSe / ZnS, CdSe / CdS, CdSe / CdS / ZnS, CdSeZn / CdS / ZnS, CdSeZn / ZnS, InP / ZnS, PbSe / PbS, PbSe / PbS, CdTe / CdS, and CdTe / ZnS.

[0072] The respective proportions of the individual phosphors and other luminescent materials in the ink compositions can be varied depending on the desired light output characteristics. The relative proportions of the individual phosphors and other luminescent materials in the various ink compositions can be adjusted so that when their emissions are blended and used in a device, such as a lighting device, they produce visible light at a given x and y value on the CIE chromaticity diagram.

[0073] In one embodiment, a film may be prepared from the ink composition. The film may be deposited on a substrate, such as a glass substrate. The film may be deposited on an LED, such as a mini-LED or micro-LED, by coating, using a doctor blade, or by printing. In one embodiment, the film is prepared by coating the ink composition onto a glass substrate using a doctor blade. The solvent may be removed, and the film is cured, such as by UV light or thermal curing.

[0074] Additional processes for preparing phosphor compositions that can be used with the systems and methods described herein are described in U.S. Pat. No. 6,499,499, filed May 4, 2023. Entitled Red-Emitting Phosphors Having Small Particle Size, Processes For Preparing And Devices Thereof PCT application number No. PCT / US2023 / 020966 and is incorporated by reference in its entirety.

[0075] In one embodiment, a lighting apparatus comprises the device. In another embodiment, a backlight apparatus comprises the device. In another embodiment, a display comprises the device. In another embodiment, the device is a self-emissive display and does not comprise a liquid crystal display (LCD). In one embodiment, the display is a microLED display, such as a phosphor-converted microLED display.

[0076] A device according to the present disclosure includes an LED light source radiatively coupled and / or optically coupled to a phosphor composition. FIGS. 1A-1E illustrate a device 10 according to various embodiments of the present disclosure. Referring to FIG. 1A, device 10 includes an LED light source 12 and a phosphor composition 14. LED light source 12 may be a UV or blue-emitting LED. In some embodiments, LED light source 12 produces blue light in a wavelength range of about 380 nm to about 460 nm. In device 10, phosphor composition 14 is radiatively coupled and / or optically coupled to LED light source 12. By radiatively coupled or coupled or optically coupled, we mean that radiation from LED light source 12 can excite phosphor composition 14, which can emit light in response to excitation by the radiation. Phosphor composition 14 may be located at or within a portion of LED light source 12, or may be remotely located at a distance from LED light source 12. In some embodiments, the device may be a backlight unit for a display application. In other embodiments, LED light source 12 is a micro LED, and the device is for a self-emissive display. FIG. 1B illustrates an exemplary embodiment in which a phosphor composition 14 is disposed on an LED light source 12. The LED light source 12 is disposed on a reflective layer 16. The reflective layer 16 reflects light from the LED light source 12 back toward the LED light source and the phosphor composition 14. The reflective layer 16 may be any material suitable for reflecting light. In one embodiment, the reflective layer 16 may be a metal layer, such as aluminum, silver, a silver alloy, or an aluminum alloy. FIG. 1C illustrates an exemplary embodiment in which the phosphor composition 14 is disposed on the LED light source 12. An encapsulant or barrier layer 18 is disposed on the phosphor composition 14. The encapsulant or barrier layer 18 may be low-temperature glass, or a polymer or resin known in the art, such as an epoxy, silicone, epoxy-silicone, acrylate, or a combination thereof. The encapsulant or barrier layer 18 must be transparent to allow light to pass through these elements. FIG. 1D illustrates an exemplary embodiment in which the LED light source 14 is shown as an array of LED light sources 12. In some embodiments, the LED light source 12 is a mini-LED or micro-LED.FIG. 1E shows an exemplary embodiment in which the phosphor composition 14 is located remotely from the LED light source 12, which is shown as an array of LED light sources 12.

[0077] The general description of exemplary LED light sources provided herein is directed to inorganic LED-based light sources. Most common white LEDs are based on blue or UV-emitting GaInN chips. Furthermore, with respect to inorganic LED light sources, the term LED light source is intended to encompass all LED light sources, such as semiconductor laser diodes (LDs), organic light-emitting diodes (OLEDs), or hybrids of LEDs and LDs. LED light sources may also be mini-LEDs or micro-LEDs, which can be used in self-emissive displays. Furthermore, unless otherwise specified, LED light sources may be replaced, supplemented, or augmented by another radiation source, and references to semiconductors, semiconductor LEDs, or LED chips are intended to refer solely to any suitable radiation source, including, but not limited to, LDs and OLEDs.

[0078] The phosphor composition 14 may be present in any form, such as a powder, glass, or composite, such as a phosphor-polymer composite or phosphor-glass composite. Furthermore, the phosphor composition 14 may be used as a layer, sheet, film, strip, dispersed particulate, or combinations thereof. In some embodiments, the phosphor composition 14 includes a uranium-based phosphor material in glass form. In some of these embodiments, the device 10 may include the phosphor composition 14 in the form of a phosphor wheel (not shown). The phosphor wheel may include the phosphor composition embedded in glass. Phosphor wheels and related devices are described in International Publication No. WO 2017 / 196779.

[0079] The phosphor composition is optically coupled or radiatively connected to an LED light source. In one embodiment, a white light blend can be obtained by blending red and green phosphor materials with an LED light source, such as a blue or UV LED.

[0080] 2 illustrates a lighting device or lamp 20 according to some embodiments. In one embodiment, the lighting device 20 may be a backlight device. The lighting device 20 includes an LED chip 22 and leads 24 electrically attached to the LED chip 22. The leads 24 may include thin wires supported by a thicker lead frame 26, or the leads 24 may include self-supporting electrodes and the lead frame may be omitted. The leads 24 provide current to the LED chip 22, thus causing the LED chip to emit radiation.

[0081] A layer 30 of phosphor composition is disposed on the surface of the LED chip 22. The phosphor layer 30 can be disposed by any suitable method, such as using a slurry or ink composition prepared by mixing the phosphor composition with a binder material or solvent (described above). One such method involves disposing a silicone slurry containing randomly suspended or uniformly dispersed phosphor composition particles around the LED chip 22. This method is merely exemplary of possible locations for the phosphor layer 30 and LED chip 22. The phosphor layer 30 can be coated on or directly onto the light-emitting surface of the LED chip 22 by coating the slurry onto the LED chip 22 and allowing it to dry. Light emitted by the LED chip 22 mixes with light emitted by the phosphor composition to produce the desired light emission.

[0082] Continuing to refer to FIG. 3 , the LED chip 22 may be encapsulated within an envelope 28. The envelope 28 may be formed of, for example, glass or plastic. The LED chip 22 may be surrounded by an encapsulant material 32. The encapsulant material 32 may be a low-temperature glass, or a polymer or resin known in the art, such as an epoxy, silicone, epoxy-silicone, acrylate, or a combination thereof. In an alternative embodiment, the lighting device 20 may include only the encapsulant material 32 without the envelope 28. Both the envelope 28 and the encapsulant material 32 must be transparent to allow light to pass through these elements.

[0083] In some embodiments shown in FIG. 3, the phosphor composition 36 4, the phosphor composition is dispersed within the encapsulant material 32 instead of being formed directly on the LED chip 22. 36 The phosphor composition may be dispersed within a portion of the encapsulant 32 or throughout the entire volume of the encapsulant 32. The blue or UV light emitted by the LED chip 22 is 36 The light is mixed with the light emitted by the illuminator 20 and the mixed light is transmitted out of the illuminator 20.

[0084] In yet another embodiment, the phosphor composition layer 34 is coated on the surface of the envelope 28 instead of being formed on the LED chip 22, as shown in FIG. 4. As shown, the phosphor layer 34 is coated on the inner surface 29 of the envelope 28, but the phosphor layer 34 may be coated on the outer surface of the envelope 28 if desired. The phosphor layer 34 may be coated on the entire surface of the envelope 28, or only on the top of the inner surface 29 of the envelope 28. The UV / blue light emitted by the LED chip 22 mixes with the light emitted by the phosphor layer 34, and the mixed light is transmitted to the outside. Of course, the phosphor composition may be located in any two or all three locations (as shown in FIGS. 4-6), or in any other suitable location, such as separate from the envelope 28, remote from it, or integrated into the LED chip 22. In one embodiment, the phosphor layer 34 may be a film and may be located remote from the LED chip 22. In another embodiment, the phosphor layer 34 may be a film and may be disposed on the LED chip 22. In some embodiments, the phosphor layer 34 may be applied to the LED chip 22 as an ink composition. In some embodiments, the phosphor layer 34 may be applied to the LED chip 22 as an ink composition and dried to form a film on the LED chip 22. In some embodiments, the phosphor composition may be a single layer or multiple layers. In some embodiments, the film has a multilayer structure, and each layer of the multilayer structure includes at least one phosphor or quantum dot material. In another embodiment, the device structure includes a layer of the phosphor composition on the LED chip and a remote layer including a quantum dot material. In another embodiment, the device structure includes a layer of the phosphor composition on the LED chip and a remote layer including a quantum dot material and a phosphor material. In another embodiment, the device structure includes a layer of the phosphor composition on the LED chip and a film including a quantum dot material located remotely from the LED chip. In another embodiment, the device structure includes a layer of the phosphor composition on the LED chip and a film including a quantum dot material and a phosphor material located remotely from the LED chip.

[0085] In any of the above structures, the lighting device 20 (Fig. 2 The LED chip 22 (FIGS. 4A-4C) may also include a plurality of scattering particles (not shown) embedded in the encapsulant material 32. The scattering particles may include, for example, alumina, silica, zirconia, or titania. The scattering particles effectively scatter the directional light emitted from the LED chip 22, preferably with negligible absorption.

[0086] In one embodiment, Figure 2, Figure 3 、 Alternatively, the lighting device 20 shown in FIG. 4 may be a backlight device. In another embodiment, the backlight device comprises a backlight unit 10. Some embodiments include a surface-mounted device (SMD) light-emitting diode 50 for backlighting applications, as shown in FIGS. 5A, 5B, and 5C. Referring to FIG. 5A, the SMD is a "side-emitting" type and has a light-emitting window 52 in the protruding portion of a light-guiding member 54. The SMD package includes an LED chip 56, as defined above, and a phosphor composition 58 described herein. FIG. 5B shows the phosphor composition 58 disposed on the LED chip 56, and FIG. 5C shows the phosphor composition 58 disposed remotely from the LED chip 56. FIGS. 5B and 5C also show the LED chip 56 and light-guiding member 54 disposed on a reflective layer 59. The reflective layer 59 reflects light from the LED chip 56 and light-guiding member 54 toward the phosphor composition 58. The reflective layer 59 may be any material suitable for reflecting light. In one embodiment, the reflective layer 59 may be a metal layer such as silver, aluminum, an aluminum alloy, or a silver alloy, etc. In another embodiment, the device may be a direct-lit display.

[0087] The phosphor compositions described herein can be used to provide devices that generate white light for display applications, such as LCD backlight units, with a wide color gamut and high brightness, or devices that generate white light for general illumination with high luminosity and a high CRI value over a wide range of target color temperatures (2000K to 10,000K).

[0088] The devices of the present disclosure include lighting and display devices for general lighting and display applications. Examples of display devices include liquid crystal display (LCD) backlight units, televisions, computer monitors, vehicle displays, laptops, computer notebooks, mobile phones, smartphones, tablet computers, and other handheld devices. When the display is a backlight unit, the phosphor composition may be incorporated into a film, sheet, or strip radiatively and / or optically coupled to an LED light source, as described in U.S. Patent Application Publication No. 2017 / 0254943. Other device examples include chromatic lamps, plasma screens, xenon-excited lamps, UV-excited marking systems, automotive headlamps, home and theater projectors, laser-excited devices, and point sensors. In one embodiment, the device may be a fast-response display that does not include an LCD. The fast-response display may also be a self-emissive display that includes phosphor-converted (PC) microLEDs. This list of applications is merely illustrative and not intended to be exhaustive.

[0089] In some embodiments, a film including the phosphor composition may be disposed on a small LED, such as a micro-LED or mini-LED. In other embodiments, the film includes a phosphor having a micron or submicron particle size. In other embodiments, the film includes nano-sized particles. In one embodiment, the film includes Mn phosphor having a D50 particle size of less than 20 μm, less than 10 μm, particularly less than 5 μm, and more particularly a nano-sized particle size. 4+It includes a doped phosphor. In another embodiment, the D50 particle size may be about 1 micron to about 20 microns. In another embodiment, the D50 particle size is about 1 micron to about 15 microns. In another embodiment, the D50 particle size is about 1 micron to about 10 microns. In another embodiment, the D50 particle size is about 1 micron to about 5 microns. In another embodiment, the D50 particle size is about 1 micron to about 3 microns. In another embodiment, the D50 particle size is about 50 nm to about 1000 nm. In another embodiment, the D50 particle size is about 100 nm to about 1000 nm. In another embodiment, the D50 particle size is about 200 nm to about 1000 nm. In another embodiment, the D50 particle size is about 250 nm to about 1000 nm. In another embodiment, the D50 particle size is about 500 nm to about 1000 nm. In another embodiment, the D50 particle size is about 750 nm to about 1000 nm. In another embodiment, the D50 particle size is from about 50 nm to about 10 microns. In another embodiment, the D50 particle size is from about 200 nm to about 5 microns. In another embodiment, the D50 particle size is from about 250 nm to about 5 microns. In another embodiment, the D50 particle size is from about 500 nm to about 5 microns. In another embodiment, the D50 particle size is from about 750 nm to about 5 microns. In another embodiment, the D50 particle size is from about 750 nm to about 3 microns.

[0090] 6 is a schematic diagram of a contact stencil printing system 100 according to one embodiment of the present disclosure. The contact stencil printing system 100 can be used to deposit a composition, such as a phosphor ink, containing a plurality of light emitting elements, including, but not limited to, LEDs, mini-LEDs, OLEDs, or micro-LEDs, onto a target substrate.

[0091] The contact stencil printing system 100 may include a substrate 102, a substrate support 104, a stencil 106, a stencil frame grip 108, and an alignment adjuster 112. The stencil 106 may be fabricated on flexible 2 mil, 3 mil, and 5 mil polyimide substrates. These thicknesses are provided by way of example only; various other thicknesses may also be used. In some embodiments, the stencil 106 is fabricated from a polyimide substrate manufactured by Kapton® or Upilex®.

[0092] The stencil 106 includes one or more openings. The one or more openings can include various shapes (e.g., circular, rectangular, square, or any other shape) with dimensions as small as 25 μm in width and / or length. The one or more openings can be created via a laser cutting tool and can include various patterns, lengths, widths, and orientations. For example, the configuration of the one or more openings can take into account parameters of the composition being deposited, including, but not limited to, the viscosity of the composition, wettability, solvent type, amount, epoxy / emulsion type, and / or PFS to YAG ratio.

[0093] The stencil 106 may be held in place by a plurality of stencil frame grips 108. The stencil 106 is disposed on a substrate 102, which is supported by a plurality of supports 104. The substrate 102 and supports 104 may rest on an adjustable surface 110. The adjustable surface 110 may be adjusted vertically via an alignment adjuster 112. More specifically, the alignment adjuster may be configured to adjust the position of the substrate 102 relative to the stencil 106 so that the stencil 106 contacts the substrate 102.

[0094] In some embodiments, composition transfer using stencil printing system 100 occurs as a result of a squeegee 120 moving across the stencil 106 while simultaneously pressing down on the stencil 106, thereby bringing the stencil 106 into contact with the substrate 102. The printing speed (e.g., the movement of the squeegee on the stencil) is important because a slower printing speed results in a greater and / or wider transfer of material due to the longer the stencil remains in contact with the substrate, and a faster printing speed results in a more controlled transfer of material due to a shorter interaction time between the substrate and stencil.

[0095] FIG. 7 illustrates a snap-off stencil printing system according to one embodiment of the present disclosure. 150 1 is a schematic diagram of a snap-off stencil printing system. 150 can be used to deposit compositions such as phosphor inks onto target substrates such as LEDs, mini LEDs, OLEDs, or micro LEDs. The stencil 106 can be fabricated on flexible 2-mil, 3-mil, and 5-mil polyimide substrates. These thicknesses are provided by way of example only; various other thicknesses may also be used. In some embodiments, the stencil 106 is fabricated from a polyimide substrate manufactured by Kapton® or Upilex®.

[0096] The stencil 106 includes one or more openings. The one or more openings can include various shapes (e.g., circular, rectangular, square, or any other shape) with dimensions as small as 25 μm in width and / or length. The one or more openings can be created via a laser cutting tool and can include various patterns, lengths, widths, and orientations. The configuration of the one or more openings can take into account parameters of the composition being deposited, including, but not limited to, the viscosity of the composition, wettability, solvent type, amount, epoxy / emulsion type, and / or PFS to YAG ratio.

[0097] Similar to the contact stencil printing system 100, a snap-off stencil printing system 150 The apparatus may include a substrate 102, substrate supports 104, a stencil 106, stencil frame grips 108, and an alignment adjuster 112. The stencil 106 may be held in place by a plurality of stencil frame grips 108. The stencil 106 is disposed on a substrate 102 supported by a plurality of supports 104. The substrate 102 and supports 104 may rest on an adjustable surface 110. The adjustable surface 110 may be adjusted vertically via the alignment adjuster 112. More specifically, the alignment adjuster may be configured to adjust the position of the substrate 102 relative to the stencil 106 so that the stencil 106 contacts the substrate 102. The printing speed (e.g., the movement of the squeeze on the stencil) is important because slower printing speeds result in more and / or wider material transfer due to the stencil remaining in contact with the substrate for a longer period of time, while faster printing speeds result in more controlled material transfer due to a shorter period of interaction between the substrate and stencil.

[0098] However, the printing system 150 The substrate 102 further comprises one or more snap-offs or spacers 130. The spacers 130 are disposed between the substrate 102 and the stencil 106, thereby separating the substrate 102 and the stencil 106 by a distance. 102 The further away from the stencil opening, the greater the 102 The difference in contact angle between the stencil and the ink is reduced, which allows for better printing uniformity over a large printing area. 150 Composition transfer using also occurs as a result of the squeegee 120 moving across the stencil 106 while simultaneously pressing down on the stencil 106, thereby bringing the stencil 106 into contact with the substrate 102.

[0099] In an exemplary embodiment, the stencil 106 is stretched evenly over the substrate 102. In some embodiments, the stencil 106 is cut shorter than the stretch limit of the stencil frame. Cutting the stencil 106 shorter than the stretch limit of the stencil frame helps eliminate ridges that could result in uneven printing. For example, in some embodiments, the stencil 106 is stretched to the upper limit of the stencil frame grip 108. This may result in the stencil 106 being stretched evenly across the entire stencil area without any ridges that could result in uneven printing. In some embodiments, an adhesive, such as tape, is attached to one or more edges of the stencil 106, which further stretches the stencil 102, thereby removing any ridges and / or ripples remaining in the stencil. In some embodiments, the adhesive comprises polyamide tape.

[0100] In some embodiments, calibration is performed before the composition is transferred. More specifically, the spacers 130 cause a misalignment between the stencil openings and the target print points. Calibration ensures that the stencil openings and the target print points are properly aligned.

[0101] In some embodiments, multi-pass printing can be used to build printed ink height and / or increase aspect ratio across the target print area. 150 The spacers 130 provide controlled and precise transfer of ink, while non-snap-off printing (e.g., printing using a contact stencil printing system 100) results in heavy ink transfer. In some embodiments (e.g., snap-off stencil printing systems 150Snap-off printing (using a contact stencil printing system 100) can be followed by non-snap-off printing (e.g., printing using the contact stencil printing system 100) to build material height and / or increase aspect ratio across the targeted print area. Snap-off printing can transfer a controlled amount of ink to build an ink base, upon which non-snap-off printing can be used to transfer more material. Using the same material base improves wetting of subsequent print runs, resulting in better ink transfer and greater height.

[0102] Figures 8A to 8 D 2 is a schematic diagram of a bank configuration 200 according to one embodiment of the present disclosure. 8A ~Figure 8D 2A-2C illustrate bank configuration 200 at different stages of a dispensing or printing process. Printing and transferring high-aspect ratio conversion layers onto small-feature light-emitting elements (e.g., mini-LEDs and / or micro-LEDs) assembled on a flat substrate surface is challenging. Bank configuration 200 enables achieving high-aspect ratio conversion layers onto small-feature light-emitting elements in a more efficient and cost-effective manner than current printing and / or dispensing techniques. For example, in some embodiments, aspect ratios of at least 0.1 (i.e., 1:10) can be achieved. In other embodiments, the aspect ratio is about 0.1 to about 10. In other embodiments, the aspect ratio is about 0.1 to about 5. In other embodiments, the aspect ratio is about 0.5 to about 5. In other embodiments, the aspect ratio is about 0.1 to about 3, more specifically, 0.1 to about 1 and 0.1 to about 0.5.

[0103] In FIG. 8A , a plurality of light-emitting elements 202 (e.g., LEDs, mini-LEDs, and / or micro-LEDs) operating at a desired color point (e.g., white light) are disposed on a substrate 210. In FIG. 8B , one or more walls 204 are disposed around each of the plurality of light-emitting elements 202. In some embodiments, each light-emitting element 202 is surrounded by a continuous wall 204. For example, each light-emitting element 202 is surrounded by multiple walls 204 that form a closed square, rectangle, or other shape, thereby forming a bank structure around each light-emitting element 202. In the embodiment shown in FIGS. 8A-8D , each light-emitting element 202 is surrounded by four walls 204 formed on a planar structure 210, forming a bank structure 206. In other embodiments, such as the embodiment shown in FIG. 9 , the walls 204 are formed in a layer 244 located above the planar substrate 210, thereby forming a well structure 246. Thus, the bank configuration 200 can include each light-emitting element 202 surrounded by a bank structure 206 or a well structure 246. In some embodiments, the bank structure 206 or well structure 246 may be formed by a method (e.g., the contact stencil printing system 100 of FIG. 6 or the snap-off stencil printing system of FIG. 7). 150 In further embodiments, snap-off printing is desirable because it allows for control of printing speed, and with the appropriate aperture dimensions, allows for the transfer of the appropriate amount of material to the desired location to fill the well structures without spilling over into adjacent pixels / color filters. Additionally, in some embodiments involving well structures, a relatively thin stencil thickness may be used for better see-through to aid in alignment at the micron scale.

[0104] In some embodiments, the walls 204 are constructed from a reflective material and can therefore act as reflectors. More specifically, the walls 204 are coated with a white surface that reflects all visible wavelengths that shine on them. The reflective material of the walls 204 can enhance the brightness of the light-emitting elements. In some embodiments, one or more of the walls 204 are constructed from a translucent material. For example, in a transparent display application, the walls 204 may be constructed from a translucent material.

[0105] In FIG. 8C , the bank structures, or alternatively the well structures, are filled with an optically active material 230. The optically active material may include a down-conversion material, such as a phosphor material. In some embodiments, the bank structures, or alternatively the well structures, are filled by dispensing and / or printing methods. For example, in some embodiments, the bank structures or well structures are filled by the contact stencil printing system 100 of FIG. 6 or the snap-off stencil printing system of FIG. 7. 150 Filled using a snap-off stencil printing system 150 enables the transfer of materials with high reproducibility and uniformity in a cost-effective manner. In other embodiments, the wells are filled by dispensing or printing methods known in the art.

[0106] FIG. 10 shows a composition deposited on a substrate 300 using a contact stencil printing system 100, and FIG. 11 shows a composition deposited on a substrate 300 using a snap-off stencil printing system. 150 10 and 11, a 3 mil stencil with 120 μm square openings on a 450 μm pitch was used. Compared to the contact stencil printing system 100, the snap-off stencil printing system 150 This allows for a greater amount of composition to be transferred to the surface of the substrate. More specifically, the distance between the substrate 102 and the stencil 106 introduced by the spacers 130 helps to remove the stencil openings after the composition has been transferred, resulting in a defined transfer of the composition. This potentially allows for a high aspect ratio (height to width) to the substrate. A high aspect ratio is desirable because a relatively high height is required to convert blue light emitted from blue light sources, such as OLEDs, LEDs, mini-LEDs, or micro-LEDs, or potentially UV light sources, to red light.

[0107] Figure 12A ~ Figure 12 D12A includes a graph depicting the aspect ratio of printed ink composition patterns deposited using snap-off stencil printing. More specifically, FIG. 12A illustrates the respective heights of the deposited ink compositions along the width 504 of the substrate. 502 and depth 506. Similarly, FIG. , 12C, and 12D indicates the respective heights 512 of the deposited ink compositions along the width 514 of the substrate. Includes graphs 510, 520, and 530, respectively. Figure 12A ~Figure 12D As can be seen, relatively high aspect ratios can be achieved in a reproducible manner using snap-off stencil printing. In the example shown in FIG. 12A, an aspect ratio of 0.1 is achieved. In another embodiment, the aspect ratio is about 0.1 to about 10. In another embodiment, the aspect ratio is about 0.1 to 5. In another embodiment, the aspect ratio is about 0.5 to 5. In another embodiment, the aspect ratio is about 0.1 to 3, more specifically, 0.1 to 1 and 0.1 to 0.5.

[0108] Figure 13A shows a printed ink composition pattern 600 deposited by snap-off stencil printing using a 2 mil stencil, and Figure 13B is a photoluminescence intensity map 610 of pattern 600 under light excitation of 457 nm and emission intensity of 630 nm. As clearly shown in Figures 13A and 13B, snap-off stencil printing deposited the ink composition only in the intended locations and did not overflow.

[0109] 14A and 14B are schematic diagrams of a high-precision pick-and-place system 700 according to one embodiment of the present disclosure. More specifically, FIGS. 14A and 14B show the pick-and-place apparatus 700 at different stages of a high-precision and high-resolution pick-and-place process. The process shown in FIGS. 14A and 14B can be used for both assembled LED panels and individual LEDs before assembly.

[0110] In Figure 14A, light emitting elements 702 are disposed on a substrate. Figure 14A illustrates preparing a light emitting surface 704 of each light emitting element 702. More specifically, each light emitting surface 704 is coated with an optical adhesive 730. In the embodiment illustrated in Figure 14A, the optical adhesive 730 is disposed on the light emitting surface 704 by spray coating using a spray nozzle 706. However, the optical adhesive 730 may also be disposed on the light emitting surface 704 by dispensing or other methods known in the art.

[0111] FIG. 14B shows an optically active film on each emitting surface 704 coated with optical adhesive 730. 732 (e.g., a film containing phosphor material) 732 The optically active film may be sized and shaped to fit the light-emitting surface 704. For example, before assembly, a large area optically active film can be cut into smaller area pieces by a laser on a sharp roller cutter or other methods known in the art. In the embodiment shown in FIG. 14B, the optically active film 732 is placed onto the light-emitting surface 704 coated with optical adhesive 730 via a high-precision pick-and-place tool 740. In some embodiments, the pick-and-place tool 740 may 732 Picked up and optically active film 732 The optical adhesive 730 is an optically active film. 732 is secured to the light emitting surface 704. In some embodiments, the optically active film 732 The optically active film is cured using hot air, UV light, and / or any other method known in the art. 732 allows the light emitting element 702 to operate at a desired color point (eg, white light).

[0112] 15 is a dip coating system 900 according to one embodiment of the present disclosure. Similar to the high precision pick and place system 700, the dip coating system 900 uses a high precision pick and place tool 940. However, the dip coating system 900 uses the pick and place tool 940 to pick up each light emitting element 902 and apply each light emitting element 902 with an ink composition. bath In some embodiments, the pick and place tool 940 picks up the light emitting element 902 and immerses the light emitting surface of the light emitting element 902 in the liquid. 904 The ink composition 950 includes a suction nozzle configured to immerse the ink composition in a bath of ink composition 950. The immersion time, surface wettability, and bath temperature determine the amount of transfer. The ink composition 950 can include a phosphor material. In some embodiments, the ink composition 950 includes a PFS phosphor and / or a KFS phosphor. Additionally or alternatively, the ink composition 950 includes an optical adhesive. The ink composition 950 can include any of the ink compositions described herein.

[0113] After the targeted immersion time, the pick-and-place tool 940 removes the light-emitting element 902 from the ink composition bath 950. The resulting coating 906 on the light-emitting element 902 is then cured. In some embodiments, the coating 906 is cured using hot air and / or UV light. Additionally or alternatively, the ink composition may be cured using any method known in the art. This process is repeated (e.g., immersing the light-emitting element 902 in the ink composition bath 950 and curing the resulting coating 906) until the desired conversion layer is achieved. The cured coating on the light-emitting element 902 enables the light-emitting element 902 to operate at a desired color point (e.g., white light). More specifically, LEDs (e.g., mini LEDs, micro LEDs, etc.) can be customized with a desired color point as components that can be assembled into any desired panel on an electronic assembly line, resulting in a relatively fast, efficient, and cost-effective process.

[0114] 16A is a top view of an exemplary red-green-blue (RGB) pixel 1000 including a blue subpixel 1010, a green subpixel 1020, and a red subpixel 1030. FIG. 16B is a side view of the exemplary RGB pixel layout 1000. Each subpixel may include a well including multiple walls. An ink composition including a blue-emitting phosphor may be deposited on the blue subpixel 1010, and an ink composition including a green-emitting phosphor may be deposited on the green subpixel 1030. 1020 An ink composition containing a red-emitting phosphor may be deposited on the red sub-pixel 1030, and an ink composition containing a red-emitting phosphor may be deposited on the red sub-pixel 1030. 1010 The ink compositions deposited on the green sub-pixel 1020 and red sub-pixel 1030 are color filter portions. 1014 , 1024 , and 1034 The ink compositions can be cured at 1000 Watts per minute (WPM) and 1000 Watts per minute (WPM). Thus, the blue subpixel 1010 is configured to emit blue light 1016, the green subpixel 1020 is configured to emit green light 1026, and the red subpixel 1030 is configured to emit red light 1036. In some embodiments, each subpixel 1010, 1020, 1030 includes a color filter material 1014, 1024, 1034, respectively. In some embodiments, stencil printing is used to deposit the ink composition. Stencil printing can be performed using a contact stencil printing system 100 (see FIG. 6) or a snap-off stencil printing system. 150 (See FIG. 7.) The ink composition can be cured using hot air, UV light, and / or any other method known in the art.

[0115] In some embodiments, the ink composition may include a refractive index of about 0.1 to about 3. In further embodiments, the ink composition may include a refractive index of about 1 to about 1.6. In further embodiments, the ink composition may include a refractive index of about 1.50. In further embodiments, the ink composition may include a refractive index of about 1.51. Ink compositions that include a relatively high refractive index may increase the effective path length of the excitation light 1040 (e.g., blue light) due to further absorption.

[0116] In some embodiments, a scattering agent is added to the subpixels, as described above. In some embodiments, the scattering agent may have a refractive index of about 0.1 to about 3. In further embodiments, the scattering agent may have a refractive index of about 1 to about 1.6. In further embodiments, the scattering agent may have a refractive index of about 1.50. In further embodiments, the scattering agent may have a refractive index of about 1.51. The scattering agent may have a relatively high refractive index, increasing the effective path length of the excitation light 1040 (e.g., blue light) for further absorption.

[0117] In some embodiments, a subpixel may be partially filled with a first ink composition and partially filled with a second ink composition. The second ink composition may be located proximate to the portion of the pixel or subpixel where the excitation light is incident (e.g., side 1002 in Figure 16B). The excitation light 1040 may be incident on the pixel and encounter the second ink composition, which may then subsequently encounter the first ink composition. The subpixel may be filled using a two-pass printing technique. Printing may be performed using a contact stencil printing system 100 (see Figure 6) or a snap-off stencil printing system. 150(See FIG. 7). The ink compositions can be cured using hot air, UV light, and / or any other method known in the art. The first ink composition and the second ink composition may have different refractive indices. For example, in some embodiments, the second ink composition has a relatively low refractive index and the first ink composition has a relatively high refractive index. For example, in some embodiments, the first ink composition has a higher refractive index than the second ink composition. This allows the excitation light to first encounter the second ink composition, reducing reflection, and then encounter the first ink composition, thereby increasing the effective excitation light path once coupled to the color filter portion. In further embodiments, the second ink composition has a refractive index of about 0.1 to about 2. In further embodiments, the second ink composition has a refractive index of about 0.1 to about 1.6. In further embodiments, the second ink composition has a refractive index of about 0.1 to about 1.51. In some embodiments, the first ink composition has a refractive index greater than about 1. In further embodiments, the first ink composition has a refractive index greater than about 1.3. In a further embodiment, the first ink composition comprises a refractive index greater than about 1.50, hi a further embodiment, the first ink composition comprises a refractive index greater than about 1.51.

[0118] In some embodiments, a subpixel may include a third ink composition in addition to the first and second ink compositions. In such embodiments, the second ink composition may have a relatively low refractive index, the first ink composition may have a relatively high refractive index, and the third ink composition may have a relatively high refractive index. In such embodiments, each of the first ink composition and the third ink composition may have a higher refractive index than the second ink composition. In further embodiments, the second ink composition includes a refractive index of about 0.1 to about 2. In further embodiments, the second ink composition includes a refractive index of about 0.1 to about 1.6. In further embodiments, the second ink composition includes a refractive index of about 0.1 to about 1.51. In some embodiments, the first ink composition includes a refractive index greater than about 1. In further embodiments, the first ink composition includes a refractive index greater than about 1.3. In further embodiments, the first ink composition includes a refractive index greater than about 1.50. In further embodiments, the first ink composition includes a refractive index greater than about 1.51. In some embodiments, the third ink composition comprises a refractive index greater than about 1. In further embodiments, the third ink composition comprises a refractive index greater than about 1.3. In further embodiments, the third ink composition comprises a refractive index greater than about 1.50. In further embodiments, the third ink composition comprises a refractive index greater than about 1.51.

[0119] In some embodiments, at least one film (not shown) is disposed on a side of one or more subpixels 1010, 1020, 1030 on which excitation light is incident or on pixel 1000 (e.g., side 1002). The at least one film may be configured to change optical properties. For example, the at least one filter may include a film that transmits blue light and reflects red and / or green light, thereby increasing brightness by increasing the amount of blue light that is incident on the subpixels 1010, 1020, and 1030, passes through the blue subpixel 1010, is converted to green light via the green subpixel 1020, and is converted to red light via the red subpixel 1030. In some embodiments, the at least one filter includes a dichroic color filter. Additionally or alternatively, the at least one film is configured to protect the ink composition from at least one of oxygen or moisture.

[0120] In some embodiments, quantum dots in color filters (QDCFs) are utilized. QDCFs can improve the color quality, viewing angle, and energy efficiency of displays. By using a blue light source, such as an OLED, LED, mini LED, or micro LED, or a UV light source, and replacing traditional color filters with QDCF materials, at least a portion of the blue light is converted into a higher wavelength range, such as red light and / or green light.

[0121] In some embodiments, the RGB pixel 1000 is part of a display device that includes a backlight unit (BLU) configured to emit blue light 1040. In such embodiments, the QDCF may include scattering agents in the blue subpixel 1010 and quantum dots in the red subpixel 1030 and green subpixel 1020 to achieve a wide color gamut. In addition to the quantum dots in the red subpixel 1030 and green subpixel 1020, at least one binder, at least one scattering agent, and / or additional color filter material that absorbs blue light may be added to minimize leakage of blue light through the subpixels, which would narrow the color gamut.

[0122] The nanometer size of quantum dots, their high absorption cross-sections, and surface termination of quantum dots with ligands have led to the commercialization of QDCF-containing display architectures. However, the use of QDCFs has several drawbacks, such as self-absorption losses. Furthermore, QDCF-containing displays typically require encapsulation of the quantum dots to prevent degradation of the quantum dots by moisture and / or oxygen. This encapsulation can lead to parallax issues. Furthermore, the required coating, shelling, printing, and / or curing processes can reduce the quantum efficiency of the quantum dots in the QDCF region. In some cases, highly loaded inks can significantly overlap the absorption and emission of quantum dots, resulting in a net effect of reduced external quantum efficiency. Traditionally, typical phosphors were considered too large for use in color filter applications, had too low quantum efficiency and absorption when synthesized in submicron sizes, and exhibited too high agglomeration to be printed into subpixels. The embodiments disclosed herein address these aforementioned issues with current QDCFs.

[0123] In some embodiments according to the present disclosure, stencil printing is used to fill the red subpixel 1030 with an ink composition. In some embodiments, the ink composition includes a KSF phosphor (K2SiF6:Mn) with a small particle size and a high manganese content. In contrast to quantum dot color filter solutions, the KSF phosphor (K2SiF6:Mn) has a narrower emission intensity, does not have self-absorption issues in thick films, and does not reduce quantum efficiency when cured into color filter sections. In further embodiments, the KSF phosphor has a D50 particle size of about 0.1 μm to about 15 μm and a Mn content of at least 2.0 wt.%. In further embodiments, the KSF phosphor has a D50 particle size of about 0.1 μm to about 8 μm and a Mn content of at least 2.0 wt.%. In further embodiments, the KSF phosphor has a D50 particle size of about 0.1 μm to about 4 μm and a Mn content of 2.0 to 4.0 wt.%. In another embodiment, the ink composition includes a small particle size, high manganese content NSF phosphor (Na2SiF6). Stencil printing can be performed using a contact stencil printing system 100 (see FIG. 6) or a snap-off stencil printing system. 150 (See FIG. 7). The ink composition can be cured using hot air, UV light, and / or any other method known in the art.

[0124] In some embodiments, as described above, stencil printing is used to coat the red subpixel 1030 with an ink composition containing a KSF phosphor. The ink composition may further include a surface agent, such as MgF2, to enable a well-dispersed KSF ink with good printability that absorbs most of the excitation light (e.g., blue or UV light) and has a quantum efficiency greater than 80%. Such ink compositions are non-self-absorbing, have good reliability, and do not require encapsulation. Furthermore, a typical KSF ink requires a fill level of 30-70% to absorb most of the excitation light in wells with a depth of 8-16 μm. In a further embodiment, the green subpixel 1020 is coated with a green emissive material, and a scattering agent or blue emissive material is added to the blue subpixel 1010. Such an embodiment enables a functional display when excited by blue LED or OLED light or UV light.

[0125] Additionally, in some embodiments, one or more walls of the subpixels are coated with a reflective (e.g., white) surface. For example, in some embodiments, one or more walls of the red subpixel 1030 are coated with a reflective (e.g., white) surface.

[0126] In some embodiments, the subpixels of the RGB pixel 1000 comprise a depth of 6-20 μm. In further embodiments, the subpixels of the RGB pixel 1000 comprise a depth of 14-20 μm. The inventors have found that increasing the well depth from 8 μm to 16 μm increases the red emission 1036 by the red subpixel 1030 by more than 30% compared to a red subpixel comprising an 8 μm well depth.

[0127] FIG. 17 shows red emission from a color filter assembly with 8 μm deep KSF phosphor-filled red subpixels. 110611 is a graph 1100 comparing inks with a depth of 16 μm. In FIG. 17, the ink refractive index and viscosity differ between the color filter parts, which will be explained in more detail below. In FIG. 17, parts 1-9 on the x-axis 1102 correspond to well depths of 8 μm, and parts 10-14 on the x-axis 1104 correspond to well depths of 16 μm.

[0128] Red emission was tested using two methods: a first method 1108 using an Edinburgh spectrometer and a second method 1110 using a QE tester. In the first method 1108, the coated color filter element was excited from a Xe lamp with 450 nm excitation selected through a monochromator. A series of diffraction gratings and mirrors resulted in a spot size of approximately 2 cm exciting the 60 x 60 mm coated color filter element. Most of the blue light striking the red subpixel was transmitted into the cured subpixel and attenuated as the KSF phosphor ink absorbed the light, resulting in less than 20% of the incident blue light being absorbed by the color filter material after passing through the cured KSF phosphor ink. The KSF phosphor ink converted the absorbed blue photons to red photons via down-conversion, and the emitted red photons passed through the color filter material and exited the backside of the color filter element. These emitted red photons then passed through a second monochromator and were detected by a photomultiplier tube (PMT) detector. The KSF phosphor printed color parts were then compared to each other based on integrated red emission intensity.

[0129] The second method 1110 utilized a QE tester containing a blue LED with a reflective ring. A KSF phosphor-coated color filter component was positioned above the ring within a closed integrating sphere, and the emitted red intensity was coupled out of the sphere via a fiber connected to a charge-coupled device (CCD) array detector. The integrated red emission intensity of each component could then be compared and normalized to the component with the highest integrated emission intensity. The correlation between the first method 1108 and the second method 1110 was 95.6%, providing confidence in the measurements.

[0130] Color filter component 14 in Figure 17 was printed from an ink composition with a refractive index greater than 1.57 and a viscosity of approximately 5000 cP. The wells of color filter component 14 were determined to be completely filled by profilometry. As clearly shown in Figure 17, component 14 yielded the greatest brightness. 3-5 micron NSF phosphor-printed color filter components have also been fabricated and measured, achieving brightness of up to 90% for color filter component 14. (Example) [Example]

[0131] Sample OS042022:

[0132] Weigh 2.2167 g of SFZ-1, 0.4545 g of BB PTh, and 0.8589 g of DGME into a 15 ml (4 dram) amber vial. The mixture was vortexed for 15–20 seconds. The first incremental amount of PFS (1.0007 g) was added, and the mixture was vortexed for 20–30 seconds. The second portion of PFS (1.0008 g) was added, and the mixture was vortexed again, followed by bath sonication for 3–5 minutes. The third portion of PFS (1.0065 g) was added, followed by vortex mixing and bath sonication. After the final addition of PFS (0.9956 g) and subsequent mixing and sonication, the slurry was too dry, so 1.1579 g of DGME was added, followed by mixing and bath sonication again. The slurry was still thick, so an additional 0.2476 g of DGME was added, followed by vortex mixing and bath sonication. The slurry was then pulse sonicated with a horn sonicator (1 second on, 2 seconds off) for a total of 20 seconds of active sonication. The slurry was warm but still thick. An additional 0.1102 g of DGME was added, followed by another vortex mixing and bath sonication. The slurry was again pulse sonicated with a horn sonicator (1 second on, 2 seconds off) for a total of 20 seconds of active sonication. The slurry was then rolled overnight and the next day pulse sonicated with a horn sonicator (1 second on, 2 seconds off) for a total of 20 seconds of active sonication. It was then placed in a desiccator under vacuum for 15 minutes to degas before coating.

[0133] Doctor blade coating on glass substrate

[0134] The ink was coated onto 1.1 mm thick 1" x 1" Corning glass substrates using an Erichsen Coatmaster 510 coater equipped with a vacuum stage. An applicator with a 1-3 mil gap was used at a speed of 10 mm / s to obtain a final film thickness of 10-30 μm.

[0135] The wet film coated glass substrates were placed on a hotplate at 110 C to remove the solvent, and then they were UV cured for 2 minutes. [Table 1]

[0136] Sample OS041522:

[0137] Weigh 2.218 g of SFZ-1, 0.4562 g of BB PTh, and 0.5515 g of DGME into a 15 ml (4 dram) amber vial. The mixture was vortexed for 15–20 seconds. The first incremental amount of PFS (1.0004 g) was added, and the mixture was vortexed for 20–30 seconds. The second portion of PFS (1.0072 g) was added, and the mixture was vortexed again, followed by bath sonication for 3–5 minutes. The third portion of PFS (1.0122 g) was added, followed by vortex mixing and bath sonication for 3–5 minutes. After the final addition of PFS (0.9768 g) and subsequent mixing and bath sonication for 3–5 minutes, the slurry was too thick, so 0.2562 g of DGME was added, followed by mixing and bath sonication again. The slurry was still thick, so an additional 0.2097 g of DGME was added, followed by vortex mixing and bath sonication for 3-5 minutes. The slurry was then pulse sonicated (1 second on, 2 seconds off) with a horn sonicator for a total of 1 minute of active sonication. The slurry became warm and thinned. The slurry was then rolled overnight, and the next day, pulse sonicated (1 second on, 2 seconds off) with a horn sonicator for a total of 1 minute of active sonication to allow it to warm. It was then placed in a desiccator under vacuum for 15 minutes to degas before coating.

[0138] Doctor blade coating on glass substrate

[0139] The ink was coated onto 1.1 mm thick 1" x 1" Corning glass substrates using an Erichsen Coatmaster 510 coater equipped with a vacuum stage. An applicator with a 1-3 mil gap was used at a speed of 10 mm / s to obtain a final film thickness of 10-30 μm.

[0140] The wet film coated glass substrates were placed on a hotplate at 110 C to remove the solvent, and then they were UV cured for 2 minutes. [Table 2]

[0141] Sample OS031422:

[0142] Weigh 3.6793 g of SFZ-1, 0.602 g of BB PTh, and 1.0089 g of DGME into a 15 ml (4 dram) amber vial. The mixture was vortexed for 15–20 seconds. 6.3621 g of PFS (total amount) was added in three portions. After each portion was added, the mixture was vortexed for 20–30 seconds, followed by 3–5 minutes of bath sonication. The slurry was then pulse sonicated in a horn sonicator for 3 minutes (1 second on, 2 seconds off) for a total of 1 minute of active sonication. This was then placed in a desiccator under vacuum for 10 minutes to degas the mixture before coating.

[0143] Doctor blade coating on glass substrate

[0144] The ink was coated onto 1.1 mm thick 1" x 1" Corning glass substrates using an Erichsen Coatmaster 510 coater equipped with a vacuum stage. An applicator with a 1-3 mil gap was used at a speed of 10 mm / s to obtain a final film thickness of 10-30 μm.

[0145] The wet film coated glass substrates were placed on a hotplate at 110 C to remove the solvent, and then they were UV cured for 2 minutes. [Table 3]

[0146] Sample OS031122:

[0147] Weigh 4.2766 g of SFZ-1, 0.2354 g of BBPTh, and 1.0381 g of DGME into a 15 ml (4 dram) amber vial. The mixture was vortexed for 15–20 seconds. The first incremental portion of PFS (2.7311 g) was added, and the mixture was vortexed for 20–30 seconds. The second portion of PFS (2.3979 g) was added, and the mixture was vortexed again. The slurry was too dry. 1.066 g of DGME was added, and the mixture was vortexed for 20–30 seconds. The third portion of PFS (2.2586 g) was added, followed by vortex mixing. The slurry was too thick, so 0.4086 g of DGME was added, followed by mixing again. The slurry was still thick, so an additional 0.2176 g of DGME was added, followed by vortex mixing. The slurry was then pulse sonicated in a horn sonicator for 3 minutes (1 second on, 2 seconds off). The slurry was too thin. 0.4131 g of PFS was added, followed by vortex mixing. The slurry was pulse sonicated in a horn sonicator for 3 minutes (1 second on, 2 seconds off) and then bath sonicated for 3-5 minutes. This was then placed in a desiccator under vacuum for 15 minutes to degas before coating.

[0148] Doctor blade coating on glass substrate

[0149] The ink was coated onto 1.1 mm thick 1" x 1" Corning glass substrates using an Erichsen Coatmaster 510 coater equipped with a vacuum stage. An applicator with a 1-3 mil gap was used at a speed of 10 mm / s to obtain a final film thickness of 10-30 μm.

[0150] The wet film coated glass substrates were placed on a hotplate at 110 C to remove the solvent, and then they were UV cured for 2 minutes. [Table 4]

[0151] Sample OS031022:

[0152] Weigh 6.1161 g of SFZ-1 and 3.0002 g of PFS into a 15 ml (4 dram) amber vial. The mixture was vortexed for 15–20 seconds and bath sonicated for 3–5 minutes. A portion of PFS (3.0064 g) was added, and the mixture was vortexed for 20–30 seconds. The mixture was too dry. 0.5112 g of DGME was added, and the mixture was vortexed for 20–30 seconds. A third portion of PFS (3.0051 g) was added, followed by vortex mixing. The mixture was too dry, and 0.5141 g of DGME was added, followed by mixing again. The slurry was then pulse sonicated (1 second on, 2 seconds off) with a horn sonicator, followed by active sonication for 1 minute. The slurry was too thin. 1.0013 g of PFS was added, followed by vortex mixing; the slurry was still too thin. 0.5086 g of PFS was added, followed by vortex mixing and bath sonication for 3-5 minutes. The slurry was pulse sonicated (1 second on, 2 seconds off) with a horn sonicator and then active sonication for 1 minute. This was then placed in a desiccator under vacuum for 15 minutes to degas the slurry before coating.

[0153] Doctor blade coating on glass substrate

[0154] The ink was coated onto 1.1 mm thick 1" x 1" Corning glass substrates using an Erichsen Coatmaster 510 coater equipped with a vacuum stage. An applicator with a 1-3 mil gap was used at a speed of 10 mm / s to obtain a final film thickness of 10-30 μm.

[0155] The wet film coated glass substrates were placed on a hotplate at 110 C to remove the solvent, and then they were UV cured for 2 minutes. [Table 5] [Example]

[0156] The following table lists examples of inks containing the small, surface-modified phosphor materials developed in this invention. The ink embodiments listed in this table demonstrate the versatility of this technology in producing fluids with tailored viscosity and using solvents with proven printability. Additionally, it illustrates how stable phosphor dispersions can be obtained using commercially available resin systems from different commercial vendors.

[0157] Experimental procedure for formulating inks for samples 1-4:

[0158] Add the resin to a glass vial using a disposable pipette. Add the solvent to the resin and shake for 3 minutes or until the resin is completely dissolved in the solvent. In some embodiments, the solvent is optional. Visually inspect the bottom corners of the vial, where the resin may be difficult to agitate. Add approximately 2 g of YAG in increments, vortexing the solution for 1 minute between each powder addition. Add approximately 1-2 g of PFS in increments, vortexing the solution for 1 minute between each powder addition. Sonicate the solution in a probe sonicator at 25% power for 1 minute in pulse mode, 1 second on, 2 seconds off (total run time approximately 3 minutes). Remove excess solvent in a rotary evaporator at a speed of 100-170 RPM and a bath temperature of 45°C under a vacuum equivalent to 75 Torr. Perform ink mass measurements at regular intervals (e.g., hourly) and stop when the target viscosity is achieved.

[0159] A resin-free, low-viscosity ink. Sample Ink 6 in the table above is composed of a 1:1 cosolvent mixture of triethylene glycol monomethyl ether (TGME) and diethylene glycol dimethyl ether (DGDE) in a mass ratio. Ethyl cellulose (EC-HH, viscosity 300 Pa-s) was used as the binder material. Ethyl cellulose was added to the TGME / DGDE cosolvent blend at 1 wt% and mixed with a stir bar until all the binder was dissolved. PFS equivalent to 8 wt% of the cosolvent / binder blend was then added. The suspension was mixed by stirring at room temperature and then shaken for 2 minutes. After vortex mixing, the suspension was bath sonicated for 10 minutes to 1 hour to reduce the average aggregate size. After sonication, the suspension was rolled on a ball mill at 60 rpm for 2 hours. The solution was then transferred to an amber glass vial and stirred at 60°C for 2 hours. [Table 6]

[0160] Ink compositions using high-viscosity resins, solvents, and additives. Ink 4 in the table is an exemplary formulation using NOA68T. This embodiment can include various types of high-viscosity resins that can be photocured or thermally cured and have starting viscosities ranging from 10,000 cP to 30,000 cP (centipoise). The amount of solvent added to the ink can range from 0% to 50% by weight of the base resin. The type of solvent can be any of the above. In exemplary inks 3 and 4, dimethylformamide (DMF) and acetone were used, respectively. The ink should contain 5% to 60% PFS phosphor material. The phosphor particle size (d50) can be in the range of 0.5 to 10 micrometers. Additives such as scattering agents (e.g., ZrO2) and auxiliary fluorescent emitters such as YAG phosphors can be used in amounts ranging from 1% to 60%.

[0161] Ink compositions using medium viscosity resins, solvents, and additives. Inks 1 and 2 in the table are exemplary formulations using NOA170 resin. This embodiment can include various types of medium viscosity resins that can be photocured or thermally cured, with starting viscosities ranging from 1,000 cP to 10,000 cP. The amount of solvent added to the ink may range from 0% to 50% by weight of the base resin. The type of solvent can be any of those listed above. In the exemplary inks 1 and 2, acetone and DMF were used, respectively. The ink must contain 5% to 60% PFS phosphor material. The phosphor particle size ( D 50) can be in the range of 0.5 to 10 micrometers. Although exemplary inks 1 and 2 do not contain such molecules, additives such as scattering agents (e.g., ZrO2) and auxiliary fluorescent emitters such as YAG phosphors can also be used in this composition in amounts ranging from 1% to 60%.

[0162] Ink composition using low viscosity resin, solvent and additives. Ink 5 in the table above is an example of a low viscosity formulation using SR454 resin. This embodiment can include various types of low viscosity resins that can be photocured or thermally cured, with starting viscosities ranging from 10 cP to 1,000 cP. The amount of solvent added to the ink may range from 0 to 10% by weight of the base resin. The type of solvent can be any of those listed above. In exemplary Ink 5, no solvent was used. The ink must contain 5% to 60% PFS phosphor material. The phosphor particle size ( D 50) can vary between 0.5 and 5 micrometers. Exemplary ink 5 contains no additives, but additives can be present in amounts ranging from 1% to 60%.

[0163] FIG. 18 shows a graph 1200 illustrating photoluminescence mapping of a blank substrate including blue, green, and red subpixels. More specifically, graph 1200 shows intensity (counts / sec) 1204 as a function of wavelength (nm) 1202 for the blank substrate. As shown in graph 1200, broad red emission from the red subpixel and broad green emission from the green subpixel were observed. FIG. 19 shows a graph 1300 illustrating intensity (counts / sec) 1304 as a function of wavelength (nm) 1302 for the KSF-filled red subpixel. As shown in graph 1300, strong red emission was observed for the KSF red subpixel at wavelengths greater than 580 nm, demonstrating an increase in the light intensity of the KSF-filled red subpixel compared to the blank substrate of FIG. 18.

[0164] FIG. 20 shows a graph 1400 of the percent external quantum efficiency (EQE) 1404 versus thickness measurement (μm) 1402 for relevant form factors to understand product performance. EQE 1404 is proportional to the amount of light absorption at 450 nm (LED or OLED) and the internal quantum efficiency. While a high EQE is desirable in the thinnest possible film, increasing thickness results in associated higher self-absorption losses. However, for emissive materials, generally the thinner the film, the lower the EQE. However, ink formulations as described herein and systems and methods for dispensing and printing such ink formulations have provided EQE improvements of 10-20%, enabling the use of thinner films.

[0165] A see-through display, or transparent display, is an electronic display that allows users to see what is shown on the screen while still being able to see through it. Primary applications of transparent displays are heads-up displays, augmented reality systems, digital signage, and general large-scale spatial light modulation. Transparent displays offer many of the benefits of digital signage while allowing viewers to see the scene behind the display by mounting light-emitting elements directly on the transparent glass to function as pixels. These see-through installations can eliminate the need for backlights or enclosures and are often used in applications including retail merchandise displays, corporate displays, museum exhibits, award / trophy cases, and heads-up displays, including automotive applications. Light sources for transparent displays can include LEDs, OLEDs, mini-EDS, and / or micro-LEDs. Generally, arrays of smaller-sized LEDs, such as mini-LEDs or micro-LEDs, enable greater transparency and resolution than larger-sized LEDs and have the potential to be brighter than OLED-based transparent displays. However, as the size of micro-LEDs decreases, their EQE may also decrease. A typical display substrate includes multiple individual micro LEDs, OLEDs, mini EDSs, and / or micro LEDs arranged in pixel groups, where the pixel groups include blue, green, and red light-emitting elements. In embodiments according to the present disclosure, the pixel groups include multiple blue- or UV-emitting LEDs, OLEDs, mini LEDs, and / or micro LEDs, and color conversion techniques can be used to create other colors for the display. In many transparent display applications, it is desirable to maximize transparency by using small LEDs, thin metallization lines, and transparent conductive materials (such as indium tin oxide) in place of the metallization lines.

[0166] In some embodiments, the metallization layer may include an electrode layer and an optional barrier layer, although other layers may be included. In some embodiments, the metallization layer has a thickness of approximately 0.1 to 2 microns. The electrode layer may provide ohmic contact to the GaN micro LED and may be formed from a high work function metal such as Ni, Au, Ag, Pd, or Pt. In some embodiments, the electrode layer may be reflective to the emitted light. In other embodiments, the electrode layer may be transparent to the emitted light. In some embodiments, the width of the laterally separated portions of the metallization layer is equal to or less than the width of the bottom surface of the array of micro pn diodes. The metallization layer is typically formed to a uniform thickness and may be deposited by various suitable methods, such as sputtering, electron beam evaporation, or plated with a seed layer.

[0167] Micro LEDs with relatively large reflective surfaces and phosphor droplets can be used to produce satisfactory light output with minimal loss of transparency. Transparent displays according to the present disclosure may be at least 50% transparent, and in some cases, at least 60% transparent. In some embodiments, the ink composition may include a relatively high refractive index. In one embodiment, the ink composition contains a KSF phosphor (K2SiF6:Mn) with a size of less than 5 microns and a Mn content of at least 1.5% by weight. 4+ Such KSF phosphors include (Y, Ga, Lu, Gd, Tb)3Al5O 12 :Ce 3+The ink composition may be mixed with a green or yellow-emitting phosphor such as KSF. The ink composition may contain a refractive index greater than about 1.49 to create scattering in the KSF phosphor, which has a refractive index of about 1.4. This increases the effective path length of the blue pump source, resulting in a bank micro-LED structure with more transmission and reflection than absorption, thus increasing red and green emission (reducing CCT) and increasing light output at a given phosphor loading. This architecture produces phosphor-converted micro-LED arrays with color temperatures greater than CCX > 0.2 and CCY > 0.2. Typical inks contain phosphor loadings of at least 20%, potentially as high as 70%, with a green to red phosphor fill ratio typically of at least about 2:1 by weight and up to about 20:1 by weight.

[0168] In some embodiments, the viscosity of the ink composition used may be from about 100 cP to about 30,000 cP. In further embodiments, the viscosity of the ink composition may be from 500 cP to 20,000 cP. In some embodiments, each of the micro LEDs is located within a bank structure (e.g., bank structure 246 shown in FIG. 9 ) that allows for low viscosity ink, perhaps down to 100 cP. Inks between 500 cP and 20,000 cP have been used to produce high-quality, uniform printed parts. Bank structures using lower viscosity inks can produce more uniform phosphor-converted micro LED arrays after printing through a degassing step before curing.

[0169] In some embodiments, at least one reflective layer is formed around each LED, OLED, mini LED, and / or micro LED. The at least one reflective layer can enable higher conversion rates by increasing the probability of higher internal reflection and / or multiple internal reflection of light passing through, thereby increasing the travel paths of light within the conversion layer and resulting in higher conversion rates.

[0170] In some embodiments, the at least one reflective layer is formed from a metal that has high reflectivity in the visible range, such as Al and Ag, and / or a metal that forms a reflective or transparent oxide, such as Al. In some embodiments, the at least one reflective layer includes one or more dielectric mirrors and / or dichroic mirrors. The dielectric mirrors and / or dichroic mirrors can be tuned to reflect specific bands and can effectively reflect narrowband radiation.

[0171] In some embodiments, at least one reflective layer is applied by screen / stencil printing (e.g., contact stencil printing system 100, snap-off stencil printing system 150 The reflective layer is deposited around each LED, OLED, mini-LED, and / or micro-LED via high-resolution masking techniques, or inkjet printing, using a laser, laser beam, or other suitable techniques. In some embodiments, at least one reflective layer is deposited prior to LED placement, possibly in the same step (and by the same deposition technique) as the metallization lines of the LED array, thus avoiding additional steps and reducing process costs. Additionally or alternatively, a scattering agent such as TiO2 or ZrO2 is added. In further embodiments, the scattering agent has a particle size of about 0.1 μm to about 4 μm.

[0172] 21 is a schematic diagram of a hybrid conductive grid 1500. The hybrid conductive grid 1500 can provide both higher reflectivity under and around the micro LEDs 1502 and higher transparency in the areas between the micro LEDs 1502. In some embodiments, the hybrid conductive grid 1500 is fabricated by alternating sputtering of indium tin oxide (ITO) 1506 and Ag conductive segments 1504 to form an interconnected conductive grid with desired properties. The hybrid conductive grid 1500 can enhance the reflective properties of at least one reflective layer described herein.

[0173] FIG. 22 shows an example LED array with a dielectric mirror. chromaticity diagram 1600 including color coordinate x (CCX) 1604 and color coordinate y (CCY) 1602 A Konica Minolta CS-150 colorimeter and luminance meter were used to measure the color point of the phosphor deposits in the LED arrays. The color point is measured before (e.g., bare LEDs) and after (e.g., coated LEDs) the phosphor is applied. To perform the measurement, the color meter must be placed some distance in front of the emitting surface. A typical color point for a bare blue-emitting LED emitting near its 450 nm peak is measured as CCX = 0.1640, CCY = 0.0130.

[0174] With a transparent substrate, some emitted light may escape through the substrate to the back of the device. This effect can be significant when phosphors are deposited on transparent areas of the substrate. Measuring the luminance and color point emitted from both sides of the device can help assess how much light is lost through the substrate, as shown in Table 7. More specifically, Table 7 shows that, compared to the light emitted from the front of the LED array with deposited phosphor (front row), approximately 30% of the light from the exemplary LED array is emitted from the back of the device (back row), shifting its color point further away from blue-emitting devices (e.g., bare LEDs). Placing a mirror behind the device reflects the luminance back to the front, and the overall color point shifts proportionally (front-reflecting row). Figure 22 shows a contour plot using the data from Table 7. [Table 7]

[0175] This specification uses examples to disclose the invention, including the best mode, and also to enable those skilled in the art to practice the invention, including making and using any device or system and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they contain equivalent structural elements that do not differ substantially from the literal language of the claims.

Claims

1. Mn in Formula 1 ４＋ An ink composition comprising a phosphor material including a doped phosphor and at least one binder material or solvent, wherein the Mn ４＋ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of greater than 2,000 cP to about 30,000 cP; Ax[MF ｙ ]:Mn ４＋ I In the formula, A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is the same as [MF ｙ ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

2. 10. The ink composition of claim 1, wherein the phosphor material is present in an amount of about 5% to about 70% by weight, based on the weight of the ink composition.

3. The Mn ４＋ The doped phosphor is K ２ [GeF ６ ]: Mn ４＋ , K. ２ [SiF ６ ]: Mn ４＋ , K. ２ [TiF ６ ]: Mn ４＋ , K. ２ [SnF ６ ]: Mn ４＋ , Cs ２ [TiF ６ ]: Mn ４＋ , Rb ２ [TiF ６ ]Mn ４＋ , Cs ２ [SiF ６ ]: Mn ４＋ , Rb ２ [SiF ６ ]: Mn ４＋ , Na ２ [SiF ６ ]: Mn ４＋ , Na ２ [TiF ６ ]: Mn ４＋ , Na ２ [ZrF ６ ]: Mn ４＋ , K. ３ [ZrF ７ ]: Mn ４＋ , K. ３ [BiF ６ ], K ３ [YF ６ ]: Mn ４＋ , K. ３ [LaF ６ ]: Mn ４＋ , K. ３ [GdF ６ ]: Mn ４＋ , K. ３ [NbF ７ ]: Mn ４＋ , and K ３ [TaF ７ ]: Mn ４＋ The ink composition of claim 1 , wherein the ink is selected from the group consisting of:

4. The Mn of Formula I ４＋ The doped phosphor is K ２ SiF ６ : Mn ４＋ or Na ２ [SiF ６ ]: Mn ４＋ The ink composition according to claim 1 , wherein

5. The Mn of Formula I ４＋ The ink composition of claim 1 , wherein the doped phosphor is coated with a surface coating comprising a metal fluoride.

6. The metal fluoride is MgF ２ or CaF ２ The ink composition according to claim 5, wherein

7. 10. The ink composition of claim 1, wherein the phosphor material further comprises a rare earth containing garnet phosphor doped with at least one of cerium, B, SiAlON, or quantum dots.

8. The ink composition of claim 1 , wherein the ink composition comprises a binder material and a solvent.

9. The ink composition of claim 1 , wherein the binder material is one or more of an epoxy, an acrylate, a methacrylate, a vinyl ester, and a siloxane.

10. The ink composition of claim 1 further comprising a scattering aid.

11. The ink composition of claim 10, wherein the scattering aid is ZrCl or TiCH nanoparticles.

12. The ink composition of claim 1 further comprising one or more other luminescent materials.

13. The ink composition of claim 12 , wherein the luminescent material comprises a quantum dot material.

14. The ink composition of claim 13 , wherein the quantum dot material comprises perovskite quantum dots.

15. Mn in Formula 1 ４＋ A device comprising an LED light source optically coupled and / or radiatively coupled to a phosphor composition comprising a doped phosphor, said Mn ４＋ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the phosphor composition combined with the LED light source has an aspect ratio of at least 0.1; A ｘ [MF ｙ ]:Mn ４＋ I In the formula, A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is the same as [MF ｙ ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

16. 16. The device of claim 15, wherein the LED light source is a UV-emitting LED or a blue-emitting LED.

17. 16. The device of claim 15, wherein the phosphor is present in an amount of about 5% to about 70% by weight, based on the weight of the phosphor composition.

18. The Mn ４＋ The doped phosphor is K ２ [SiF ６ ]: Mn ４＋ , K. ２ [TiF ６ ]: Mn ４＋ , K. ２ [SnF ６ ]: Mn ４＋ , Cs ２ [TiF ６ ]: Mn ４＋ , Rb ２ [TiF ６ ]Mn ４＋ , K. ２ [GeF ６ ]: Mn ４＋ , Cs ２ [SiF ６ ]: Mn ４＋ , Rb ２ [SiF ６ ]: Mn ４＋ , Na ２ [SiF ６ ]: Mn ４＋ , Na ２ [TiF ６ ]: Mn ４＋ , Na ２ [ZrF ６ ]: Mn ４＋ , K. ３ [ZrF ７ ]: Mn ４＋ , K. ３ [BiF ６ ], K ３ [YF ６ ]: Mn ４＋ , K. ３ [LaF ６ ]: Mn ４＋ , K. ３ [GdF ６ ]: Mn ４＋ , K. ３ [NbF ７ ]: Mn ４＋ , and K ３ [TaF ７ ]: Mn ４＋ The device of claim 15, wherein the device is selected from:

19. The Mn of Formula I ４＋ The doped phosphor is K ２ SiF ６ : Mn ４＋ or Na ２ [SiF ６ ]: Mn ４＋ 16. The device of claim 15, wherein:

20. The Mn of Formula I ４＋ 16. The device of claim 15, wherein the doped phosphor is coated with a surface coating comprising a metal fluoride.

21. The metal fluoride is MgF ２ or CaF ２ 21. The device of claim 20, wherein:

22. 16. The device of claim 15, wherein the phosphor composition further comprises a rare earth containing garnet phosphor doped with at least one of cerium, B, SiAlON, or quantum dots.

23. The device of claim 15 , wherein the phosphor composition comprises a binder material and a solvent.

24. 24. The device of claim 23, wherein the binder material is one or more of an epoxy, an acrylate, a methacrylate, a vinyl ester, and a siloxane.

25. The device of claim 15 further comprising a scattering aid.

26. The scattering aid is ZrOh or TiO ３ 26. The device of claim 25, which is a nanoparticle.

27. 16. The device of claim 15, wherein the phosphor composition further comprises one or more other luminescent materials.

28. 30. The device of claim 27, wherein the light emitting material comprises a quantum dot material.

29. 30. The device of claim 28, wherein the quantum dot material comprises perovskite quantum dots.

30. A lighting apparatus comprising the device of claim 15.

31. A backlighting apparatus comprising the device of claim 15.

32. A display apparatus comprising a device according to claim 15.

33. 16. The device of claim 15, wherein the LED light source is a mini LED or a micro LED.

34. A television comprising the backlight device according to claim 31.

35. A mobile phone comprising the backlight device according to claim 31.

36. A computer monitor comprising the backlight device of claim 31.

37. A laptop comprising the backlight device according to claim 31.

38. A tablet computer comprising the backlight device according to claim 31.

39. An automotive display comprising the backlight device according to claim 31.

40. The device of claim 15 , wherein the device is a self-emissive display.

41. 1. A method for inkjet printing, flexographic printing, or microdispensing printing, comprising printing an ink composition, wherein the ink composition comprises an Mn ４＋ The ink composition includes a low viscosity ink composition containing a phosphor material including a doped phosphor and at least one binder material or solvent, and the Mn ４＋ the doped phosphor has a D50 particle size of about 0.5 microns to about 5 microns, and the ink composition has a viscosity of about 10 cP to about 1000 cP; A ｘ [MF ｙ ]:Mn ４＋ I wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MFy] ion; and y is 5, 6, or 7.

42. 1. A method for screen printing, direct write printing, aerosol jet printing, gravure printing, flexographic printing, or microdispensing printing, comprising printing an ink composition, wherein the ink composition comprises a Mn ４＋ The ink composition includes a medium viscosity ink composition including a phosphor material containing a doped phosphor and at least one binder material or solvent, and the Mn ４＋ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of about 1000 cP to about 10,000 cP; Ax[MF ｙ ]:Mn ４＋ I In the formula, A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is the same as [MF ｙ ] is the absolute value of the charge of the ion, and y is 5, 6 or 7.

43. 1. A method for screen printing, direct write printing, or extrusion comprising printing or extruding an ink composition, wherein the ink composition comprises an Mn ４＋ The present invention also includes a high viscosity ink composition containing a phosphor material including a doped phosphor and at least one binder material or solvent, and the Mn ４＋ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of about 10,000 cP to about 30,000 cP; A ｘ [MF ｙ ]:Mn ４＋ I In the formula, A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is the same as [MF ｙ ] is the absolute value of the charge of the ion, and y is 5, 6 or 7.

44. a color filter component comprising a well, a first ink phosphor composition, and a second ink phosphor composition, the first ink composition having a high refractive index and the second ink phosphor composition having a low refractive index, the second ink phosphor composition being disposed proximate to a surface on which excitation light is incident; The first ink phosphor composition and the second ink phosphor composition are each a phosphor of Formula 1 ４＋ The phosphor material includes a doped phosphor and at least one binder material or solvent, and the Mn ４＋ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of about 10,000 cP to about 30,000 cP; Ax[MF ｙ ]:Mn ４＋ I In the formula, A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is the same as [MF ｙ ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

45. 45. The color filter assembly of claim 44, wherein the refractive index of the first ink composition is greater than about 1.5, and the refractive index of the second ink is from about 0.1 to about 1.

5.

46. 46. ​​The color filter assembly according to claim 45, wherein the wells have a depth of about 6 μm to about 20 μm.

47. 46. ​​The color filter assembly of claim 45, wherein at least one wall of the well is coated with a reflective material.

48. 46. ​​The color filter element of claim 45, wherein at least a portion of the surface onto which the excitation light is incident is coated with at least one film configured to change the optical properties or improve the reliability of the color filter element.

49. 1. A method comprising depositing a first ink composition into wells of a color filter component and subsequently depositing a second ink composition into the wells of the color filter component, wherein the first ink composition has a high refractive index and the second ink composition has a low refractive index, the second ink composition being disposed proximate to a surface on which excitation light is incident; The first ink phosphor composition and the second ink phosphor composition are each a phosphor of Formula 1 ４＋ The phosphor material includes a doped phosphor and at least one binder material or solvent, and the Mn ４＋ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of about 10,000 cP to about 30,000 cP; Ax[MF ｙ ]:Mn ４＋ I In the formula, A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is the same as [MF ｙ ] is the absolute value of the charge of the ion, and y is 5, 6 or 7.

50. 50. The method of claim 49, wherein the first ink composition has a refractive index greater than about 1.5 and the second ink has a refractive index between about 0.1 and about 1.

5.

51. 1. A light emitting array comprising a plurality of mini LEDs or micro LEDs, each mini LED or micro LED encapsulated within a bank or well structure, the bank or well structure configured to contain an ink composition deposited within the bank or well structure; The ink composition comprises Mn ４＋ The phosphor material includes a doped phosphor and at least one binder material or solvent, and the Mn ４＋ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the ink composition has a viscosity of about 10,000 cP to about 30,000 cP; Ax[MF ｙ ]:Mn ４＋ I In the formula, A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is the same as [MF ｙ ] is the absolute value of the charge of the ion, and y is 5, 6, or 7.

52. 1. A transparent display comprising a mini-LED array or a micro-LED array coated with a phosphor ink composition, the transparent display having a transparency of at least 50%, and the phosphor ink composition comprising a Mn ４＋ The doped phosphor includes the Mn ４＋ the doped phosphor has a D50 particle size of about 0.5 microns to about 15 microns, and the phosphor ink composition has an aspect ratio of at least 0.1; A ｘ [MF ｙ ]:Mn ４＋ I In the formula, A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is the same as [MF ｙ ] is the absolute value of the charge of the ion, and y is 5, 6 or 7.

53. 53. The transparent display of claim 52, wherein each mini LED of the mini LED array or each micro LED of the micro LED array is surrounded by a bank structure or a well structure.

54. 53. The transparent display of claim 52, wherein the phosphor ink composition further comprises a quantum dot material.

55. 53. An automotive display comprising the transparent display of claim 52.

56. A television comprising the display device of claim 32.

57. A mobile phone comprising the display device of claim 32.

58. 33. A computer monitor comprising the display device of claim 32.

59. A laptop comprising a display device according to claim 32.

60. A tablet computer comprising the display device of claim 32.

61. 33. An automotive display comprising the display device of claim 32.

62. 52. The light emitting array of claim 51, wherein the phosphor material further comprises a rare earth containing garnet phosphor doped with at least one of cerium, B, SiAlON, or quantum dots.

63. 63. The light emitting array of claim 62, wherein the rare earth garnet phosphor comprises yttrium aluminum garnet phosphor (YAG).

64. 52. The light emitting array of claim 51, wherein one or more walls of the bank structure or the well structure are coated with a reflective material.

65. 52. The light emitting array of claim 51, wherein the bank structure or the well structure is rectangular in shape.

66. 53. The transparent display of claim 52, wherein the phosphor material further comprises a rare earth containing garnet phosphor doped with at least one of cerium, B, SiAlON, or quantum dots.

67. 67. The transparent display of claim 66, wherein the rare earth garnet phosphor comprises yttrium aluminum garnet phosphor (YAG).

68. 54. A transparent display according to claim 53, wherein one or more walls of the bank structure or the well structure are coated with a reflective material.

69. 54. The transparent display of claim 53, wherein the bank structure or the well structure is rectangular in shape.

70. 53. The transparent display of claim 52, wherein the transparent display has a transparency of at least 60%.

71. 8. The ink composition of claim 7, wherein the rare earth garnet phosphor comprises 1% to 60% of the phosphor material.

72. The ink composition of claim 7 , wherein the rare earth garnet phosphor comprises yttrium aluminum garnet phosphor (YAG).

73. The rare earth garnet phosphor and Mn ４＋ 8. The ink composition of claim 7, wherein the fill ratio of the doped phosphor is from 2:1 by weight to 20:1 by weight.

74. 23. The device of claim 22, wherein the rare earth garnet phosphor comprises between 1% and 60% of the phosphor material.

75. 23. The device of claim 22, wherein the rare earth garnet phosphor comprises yttrium aluminum garnet phosphor (YAG).

76. The rare earth garnet phosphor and Mn ４＋ 23. The device of claim 22, wherein the fill ratio of the doped phosphor is from 2:1 by weight to 20:1 by weight.

77. 1. A method comprising depositing an ink composition on a substrate comprising a plurality of mini or micro LEDs, the ink composition comprising a Mn ４＋ The ink composition includes a low viscosity ink composition containing a phosphor material including a doped phosphor and at least one binder material or solvent, and the Mn ４＋ the doped phosphor has a D50 particle size of about 0.5 microns to about 5 microns, and the ink composition has a viscosity of greater than 2,000 cP to about 30,000 cP; Ax[MF ｙ ]:Mn ４＋ I In the formula, A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; and x is the same as [MF ｙ ] is the absolute value of the charge of the ion, and y is 5, 6 or 7.

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