WO2025024076A1

WO2025024076A1 - Quantum dot color conversion apparatus and methods of making the same

Info

Publication number: WO2025024076A1
Application number: PCT/US2024/035350
Authority: WO
Inventors: Robert Alan Bellman; Li-Wei Chou; Dmitri Vladislavovich Kuksenkov; Mark Alejandro Quesada
Original assignee: Corning Inc
Current assignee: Corning Inc
Priority date: 2023-07-21
Filing date: 2024-06-25
Publication date: 2025-01-30
Anticipated expiration: 2026-01-21
Also published as: CN119364956A

Abstract

Apparatus, devices, and methods of forming apparatuses and devices are provided. The apparatus comprises a color conversion cell disposed between a first substrate and a second substrate. The color conversion cell comprises a low-index material layer adjacent a color filter, wherein either the low-index material layer or the color filter is adjacent the first substrate. The color conversion cell further comprises a color conversion matrix comprising a plurality of quantum dots within a medium adjacent the second substrate and one of either the low-index material layer or the color filter. The color conversion cell is bound between a first wall and a second wall, each comprising an absorption portion and a reflective portion. The first substrate extends between the absorption portion of the first wall and the second wall, and the second substrate extends between the reflective portion of the first wall and the reflective portion of the second wall.

Description

QUANTUM DOT COLOR CONVERSION APPARATUS AND METHODS OF MAKING

THE SAME

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under U.S.C. § 119 of U.S. Provisional Application Serial No. 63/528201 filed on July 21, 2023, the content of which is relied upon and incorporated herein by reference in its entirety.

FIELD

[0002] Embodiments herein relate generally to color converter apparatuses, and more particularly, to designs for color converters of light emitting diode devices to decrease absorption and increase efficiency of the color conversion.

BACKGROUND

[0003] Light-emitting diodes (LEDs), such as micro-LEDs, mini-LEDs, and organic lightemitting diodes (OLEDs), are used in a variety of applications. For example, they may be used in display panels such as in mobile devices, laptops, tablets, computer monitors, automotive displays, smartwatches, and television displays, as well as in backlights and signage. These LEDs can be integrated with color conversion elements such as quantum dot color converters (e.g., quantum dot color filters) to emit light of various colors, such as red light and green light. For instance, the LEDs may emit blue light, which excites red and green quantum dots to emit red and green light, respectively.

[0004] Information displays may be continuously refined for higher optical efficiencies, providing the viewer with an optimal brightness, color-gamut, high-contrast, and high- resolution experience in a pixel-by-pixel format at low cost. Emissive displays may be based on quantum dot (QD) excitation from light emitting diode (LED) arrays, or organic light emitting diode (OLED) arrays. Emissive displays all have many of the same optical efficiency requirements. Each layer of an emissive display contributes to absorptive, scattering, reflective, and transmissive characteristics of the display.

[0005] Light at high output angles may be trapped inside the cover glass of a display due to, for example, total internal reflection (TIR). In displays utilizing quantum dots (e.g., quantum size particles of any shape, but often referred to as “dots”), the quantum dot layers re-emit light at various angles, so that there may be a significant amount of light experiencing TIR. The light reflected back by TIR may be absorbed by a color filter of a different color or the same color, or a so-called black matrix material, thereby resulting in a loss in amount of light ultimately emitted by the display.

BRIEF SUMMARY

[0006] Embodiments of the present disclosure are directed towards apparatus and methods related to color converting devices which increase the efficiency and amount of light emitted from the device. In order to increase efficiency of the display, it is desirable to increase the amount of light that is exiting at lower angles from each of the color cells, for example by “recycling” and redirecting the higher angle rays. In this regard, the apparatuses comprise a color cell including a color conversion matrix having a plurality of quantum dots suspended in a matrix, a low-index material layer positioned adjacent the color conversion matrix, and a color filter disposed adjacent the low-index material layer opposite the color conversion matrix. The color cell is bound by a plurality of walls (e.g., a first wall and a second wall). Each wall of the plurality of the walls comprises an absorbing portion and a reflective portion. The absorption portion is positioned adjacent the color filter, while the reflective portion is positioned adjacent to the color conversion matrix and the low-index material layer. In this regard, the reflective portion causes any light incident on it to be reflected back within the individual color cell, and the absorption portion prevents ambient light from being reflected by the reflective portion, and directs the light to escape through the color filter (as is desirable). Each color cell within the apparatus emits about the same amount of light, when excited with the same amount of LED/OLED light, and produces an even output. The apparatus additionally includes a substate which extends between the plurality of walls, specifically between the absorption portions. A light source to emit light is positioned adjacent the color cell between the plurality of walls, specifically the reflective portions.

[0007] In an example embodiment, an apparatus is provided. The apparatus comprises a color conversion cell. The color conversion cell comprises a low-index material layer, a color filter disposed adjacent the low-index material layer and a color conversion matrix. The color conversion matrix comprises a plurality of quantum dots and a medium. The color conversion matrix is disposed adjacent one of either the color filter or the low-index material layer. The apparatus further comprises a first wall and a second wall, wherein the color conversion cell is bound between the first wall and the second wall. Each of the first wall and the second wall comprise a reflective portion and an absorption portion. The apparatus further includes a first substrate positioned adjacent the color conversion cell and extends between the absorption portion of the first wall and the second wall. The apparatus further includes a second substrate positioned adjacent the color conversion matrix of the color conversion cell, extending between the reflective portion of the first wall and the reflective portion of the second wall.

[0008] In some embodiments, the absorption portion may be a dark mirror. In some embodiments, the dark mirror may comprise an interference filter and an opaque metal layer. In some embodiments, the opaque metal layer may comprise chromium and either chromium oxide or chromium oxynitride. In some embodiments, the opaque metal layer may be aluminum. In some embodiments, the absorption portion may be a black polymer containing a black pigment. In some embodiments, the black pigment may be carbon black. In some embodiments, the absorption portion may define a thickness of less than 300 nanometers. In some embodiments, the absorption portion may be a metal-dielectric structure.

[0009] In some embodiments, the reflective portion may comprise embedded particles. In some embodiments, the reflective portion may comprise a polymer comprising chemically coupled metal nanoparticles. In some embodiments, the reflective portion may comprise a reflective metal.

[0010] In some embodiments, the first wall may define a first wall thickness and the second wall may define a second wall thickness. Each of the first wall thickness and the second wall thickness may be about 10 microns.

[0011] In another example embodiment, a color converting apparatus is provided. The color converting apparatus comprises a first color converting cell and a second color converting cell. The first color converting cell comprises a low-index material layer adjacent a color filter. The first color converting cell further comprises a color conversion matrix comprising a plurality of quantum dots and a medium, the color conversion matrix positioned adjacent either the low-index material layer or the color filter. The second color converting cell comprises a diffusion matrix comprising a plurality of light scattering particles and a second color filter disposed adjacent the diffusion matrix. The color converting apparatus further comprises a plurality of walls, each comprising a reflective portion and an absorption portion. The first color converting cell is bound between a first wall and a second wall, and the second color converting cell is bound between the second wall and a third wall. The color converting apparatus further comprises a first substrate positioned adjacent the first color converting cell and the second color converting cell. The first substrate extends between the absorption portion of the first wall and the third wall. The color converting apparatus further comprises a second substrate positioned adjacent the first color converting cell and the second color converting cell. The second substrate extending between the reflective portion of the first wall and the third wall.

[0012] In some embodiments, the absorption portion may be a dark mirror. In some embodiments, the dark mirror may comprise an interference filter and an opaque metal layer. In some embodiments, the opaque metal layer may comprise chromium and either chromium oxide or chromium oxynitride. In some embodiments, the opaque metal layer may be aluminum. In some embodiments, the absorption portion may be a black polymer containing a black pigment. In some embodiments, the absorption portion may define a thickness of less than 300 nanometers.

[0013] In some embodiments, the reflective portion may comprise embedded particles. In some embodiments, the reflective portion may comprise a polymer comprising chemically coupled metal nanoparticles. In some embodiments, the plurality of walls each define a wall thickness of about 10 microns.

[0014] In some embodiments, the color converting apparatus may further comprise a third color converting cell. The third color converting cell may comprise a third-low index material layer, and a third color filter disposed adjacent the third low-index-material layer. The third color converting cell may further comprise a third color conversion matrix comprising a third plurality of quantum dots and a third medium. The third color conversion matrix may be disposed adjacent one of the third low-index material layer or the third color filter. The third color converting cell may be bound by the third wall and a fourth wall. In some embodiments, the first substrate may extend to the absorption portion of the fourth wall, and the second substrate may extend to the reflective portion of the fourth wall.

[0015] In yet another example embodiment, a method of forming a color converting apparatus is provided. The method comprises forming at least a first wall and a second wall on a first substrate, each of the first wall and the second wall comprising an absorption portion and a reflective portion. The method further comprises forming at least one color converting cell on the first substrate between the first wall and the second wall. The at least one color converting cell comprising a low-index material layer adjacent a color filter. The first color converting cell further comprises a photoresist layer positioned adjacent either the low-index material layer or the color filter. The method further comprises securing a second substrate to the reflective portion of each of the first wall and the second wall.

[0016] In some embodiments, the absorption portion may be an interference filter and an opaque metal layer. In some embodiments, the absorption portion may be a photomask. In some embodiments, the reflective portion may be formed via photolithography. In some embodiments, the reflective portion may comprise an electroplated polymer. In some embodiments, the reflective portion may comprise a polymer mixed with metal particles. In some embodiments, the reflective portion may comprise a polymer mixed with light scattering particles.

[0017] In yet another example embodiment, a display is provided. The display comprises a color conversion cell. The color conversion cell comprises a low-index material layer, a color filter disposed adjacent the low-index material layer and a color conversion matrix. The color conversion matrix comprises a plurality of quantum dots and a medium. The color conversion matrix is disposed adjacent one of either the color filter or the low-index material layer. The display further comprises a first wall and a second wall, wherein the color conversion cell is bound between the first wall and the second wall. Each of the first wall and the second wall comprise a reflective portion and an absorption portion. The display further includes a first substrate extends between the absorption portion of the first wall and the second wall. The apparatus further includes a second substrate, wherein a light source extends between the reflective portion of the first wall and the reflective portion of the second wall.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) [0018] Reference will now be made to the accompanying drawings, which are not drawn to scale, and wherein:

[0019] FIG. 1 illustrates an example device, in accordance with some examples discussed herein;

[0020] FIGs. 2A-B illustrate cross-sectional views of example color converting apparatus, in accordance with some embodiments discussed herein;

[0021] FIG. 3 illustrates a cross-sectional view of another example color converting apparatus, in accordance with some embodiments discussed herein;

[0022] FIGs. 4A- B illustrate graphs depicting simulated reflectance spectra in air, in accordance with some embodiments discussed herein;

[0023] FIG. 5 illustrates a flow chart of an example method for forming an apparatus in accordance with some embodiments discussed herein; [0024] FIG. 6 illustrates a flow chart of an example method of forming a wall, in accordance with some embodiments discussed herein;

[0025] FIG. 7 illustrates a flow chart of an example method of forming an absorption portion of a wall, in accordance with some embodiments discussed herein; and

[0026] FIGs. 8-10 illustrate flow charts of example methods of forming a reflective portion of a wall, in accordance with some embodiments discussed herein.

DETAILED DESCRIPTION

[0027] Some example embodiments will not be described more fully herein with reference to the accompanying drawings, in which some, but not all example embodiments are shown. Indeed, the examples described and pictured herein should not be construed as being limiting to the scope, applicability or configuration of the present disclosure. Rather, these example embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout.

[0028] Directional terms as used herein- for example, up, down, left, right, front, back, top, bottom, vertical, and horizontal - are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0029] FIG. 1 illustrates a color converting device 100 that includes a plurality of walls 119 disposed between a first substrate 105 and a second substrate 140. Each of the plurality of walls 119 includes an absorption portion 110 and a reflective portion 115. The reflection portion 115 provides a highly reflective surface over a broad spectral range, such as over visible wavelengths. In some embodiments, the reflective portion 115 may allow for more efficient color conversion of incident blue photons compared to conventional color converters. In contrast, the absorption portion 110 provides a dark portion to absorb light and prevent ambient light reflection and cross talk between different color cells (such as illustrated regarding FIG. 3).

[0030] In some embodiments, the second substrate 140 may be adhered (e.g., laser welded, adhesively attached, etc.) to a surface of the wall 119. For example, the second substrate 140 may be connected to the reflective portion 115 of the wall 119 at an interface 123. In some embodiments, the second substrate 140 may include a light emitting element to emit light into a color conversion matrix 125 including a medium 127 and a plurality of luminescent emitter particles 126 (e.g., quantum dots). In some embodiments, the plurality of luminescent emitter particles may change the wavelength of the light, thereby changing the color of the light which escapes a top surface 104 of the first substrate 105. To improve the light distribution and coloration of the color converting device more layers may be added between the first substrate 105 and the second substrate 140 to improve light recycling and efficiency.

[0031] FIGs. 2A-B illustrate cross-sectional views of example color converting apparatus 200, 200’. The color converting apparatus 200, 200’ may be a part of a display device and may provide a color converting function. The color converting apparatus 200, 200’ may comprise a color converting cell 245, 245’ bound between a plurality of walls 219 (e.g., a first wall and a second wall) and by a first substrate 205 and a second substrate 240.

[0032] In some embodiments, the first substrate 205 may be configured to allow light to escape. In some embodiments, the first substrate may be a glass substrate including a glass material such as aluminosilicate, alkali-aluminosilicate, borosilicate, alkali borosilicate, aluminumoborosilicate, alkali-aluminoborosilicate, soda lime, or other suitable glasses. Nonlimiting examples of commercially available glasses suitable for use as a first substrate 205 include EAGLE XG®, Lotus™, Willow®, Iris™, and Gorilla® glasses from Coming Incorporated. In some embodiments, the first substrates 205 may have a refractive index within a range, for example, between about 1.5 and 2.4. In some embodiments, the first substrate may have a substrate thickness within a range, for example, between about 0.1 millimeters to about 2 millimeters

[0033] In some embodiments, the second substrate 240 may comprise a reflective surface facing the color conversion matrix 225, and may include a light source. In this regard, the second substrate 240 may include a metal electrode for quantum dot OLED designs, or a dichroic mirror added onto the second substrate 240. The reflective surface on the second substrate 240 may increase light recycling within the color converting cell 245, 245’, and thus, may improve the efficiency of the color converting apparatus 200, 200’.

[0034] In some embodiments, the color converting cell 245, 245’ may convert blue light emitted from an LED or an OLED to a desired color. The emission color may be determined by the type of luminescent emitter positioned within the color converting cell 245, 245’. In this regard, different luminescent emitters may cause varying reactions with the blue light. In some embodiments, color specific quantum dots may be used as the luminescent emitter to change the emitted blue light to, for example, either red or green. The color converting cell 245, 245’ may comprise one or more components to filter and increase the output of the desired color from the color converting cell, while preventing other colors light waves from being emitted. [0035] The color converting cell 245, 245’ may include a color conversion matrix 225. The color conversion matrix 225 includes a plurality of quantum dots 226 suspended in a medium 227. In some embodiments, the color conversion matrix 225 may further include light scattering particles 228 suspended within the medium 227. As will be discussed herein, the light scattering particles 228 may increase scattering of blue light emitted from backplane emitters. In some embodiments, the medium is a polymer. In some embodiments, the color conversion matrix 225 may have a refractive index of between about 1.4 and 2.2.

[0036] In some embodiments, rather than quantum dots, other luminescent emitter particles may be utilized. For example, phosphors, fluorophores, nanocrystals, or other suitable luminescent emitter particles.

[0037] In some embodiments, the color converting cell 245 may comprise a color filter 220. The color filter 220 may define a first filter surface 220a and a second filter surface 220b, wherein the second filter surface 220b is opposite the first filter surface 220b. In some embodiments, such as illustrated in FIG. 2 A, the first filter surface 220a may be adjacent the first substrate 205. In some embodiments, such as illustrated in FIG. 2B, the second filter surface 220b may be adjacent the color conversion matrix 225. The color filter 220 may extend between the plurality of walls 219. In some embodiments, the color filter 220 may have a filter thickness, which may extend between both the absorption portion 210 and the reflective portion 215 of the plurality of walls 219, while in other embodiments, the color filter 220 may extend only within the reflective portion 215 of the plurality of walls 219. In some embodiments, the color filter thickness may be between about 2 micrometers to about 10 micrometers.

[0038] The color filter 220 may correspond to the desired color output for the color converting cell 245, 245’. In this regard, a red color filter layer may be positioned over a red color conversion matrix, a green color filter layer may be positioned over a green color conversion matrix, and a blue color filter may be positioned over a blue color conversion matrix. In some embodiments, the color filter 220 may include pigments or dyes within a polymer to create the desired color.

[0039] In some embodiments, the color converting cell 245, 245’ may comprise a low-index material layer 235. The low-index material layer may be formed of any material with homogeneous or nano-structured (“nano” means at a scale smaller than the wavelength of light, so that the light is seeing it as a homogeneous medium with an average index), that has an average refractive index lower than that of display glass and commonly used polymers, i.e. 1.5. Some example low-index materials may include, without limitation: homogeneous low index materials , such as fluorinated polymers, that have the refractive index in the range of 1.3-1.4; porous materials with a closed pore structure in the range of 1.1-1.3, such as a polymer matrix containing hollow nanoparticles, for example hollow silica nanoparticles; open pore structure materials structured (for example of an array of nano-sized columns with space (air) between them) or, more commonly unstructured, such as fumed silica, which can reach the index of n=l.l and aerogels, which can reach the record low index of n=1.05 (90% porosity) and are significantly durable. The low-index material layer 235 may define a first surface 235 a and a second surface 235b opposite the first surface 235 a. In some embodiments, such as illustrated in FIG. 2 A, the low-index material layer 235 may be disposed between the color filter 220 and the color conversion matrix 225, such that the first surface 235a abuts the second filter surface 220b and the second surface 235b abuts the color conversion matrix 225. In other embodiments, such as illustrated in FIG. 2B, the low-index material layer 235 may be disposed between the color filter 220 and the first substrate 205 such that the first surface 235a abuts the first substrate 205 and the second surface 235b abuts the first filter surface 220b.

[0040] In some embodiments, the low-index material layer 235 may have a refractive index less than about 1.5. The low-index material layer 235 may have a layer thickness within a range, for example about 2 micrometers to about 10 micrometers. In some embodiments, the low-index material layer 235 may include a plurality of gas filled (e.g., air filled) pores sealed by the color conversion matrix 225. In some embodiments, the low-index material layer 235 may include aerogel. In other embodiments, the low-index material layer 235 may include a mixture of hollow silica nanoparticles and a polymer binder. In some embodiments, the low- index material layer 235 may comprise properties which prevent the color conversion matrix 225 from filling in the porous surface. In other embodiments, the medium 227 of the color conversion matrix 225 may exhibit a large surface tension such that the color conversion matrix 225 does not penetrate the porous surface of the low-index material layer 235.

[0041] In some embodiments, the color conversion matrix 225 may be positioned adjacent one of either the low-index material 235 or the color filter 220. However, it may be beneficial for the second surface 235b of the low-index material layer 235 to be adjacent the color conversion matrix 225, and the first surface 235a of the low-index material layer 235 to be adjacent to the second filter surface 220b of the color filter 220. In this regard, positioning the low-index material layer 235 adjacent the color conversion matrix 225 decreases, and in some instances may inhibit, any coupling losses. To explain, quantum dots emit light at all possible angles. Without including the low-index material layer 235, high-angle light rays may experience total internal reflection (TIR) at the glass-air boundary. The low-index material layer 235 adjacent the color conversion matrix 225 causes the high-angle light rays to be recycled within the color conversion matrix 225, where the high-angle light rays may be converted to low-angle light rays and capable of output by the color conversion matrix 225. Further, the color filter 220 may cause a lower amount of ambient light to be reflected into the color converting cell 245, 245’ when the color filter 220 is adjacent the first substrate 205, as compared to when the low-index material layer 235 is adjacent the first substrate 205. Therefore, there may be a greater improvement in efficiency when the low-index material layer 235 abuts the color conversion matrix 225, as illustrated in FIG. 2A.

[0042] Returning to the color conversion matrix 225, in some embodiments the color conversion matrix 225 may additionally include scattering particles 228. The scattering particles 228 may be titania (TiO2), niobia, hafnia, barium titanate, hollow silica, or other materials with the refractive index significantly higher or significantly lower than that of the medium 227. The scattering particles 228 may scatter blue light emitted from backplane emitters, thereby increasing the effective path length and allow increased absorption of the blue light with a lower color conversion matrix 225 thickness or a lower concentration of quantum dots 226 within the color conversion matrix 225.

[0043] Emission from the quantum dots 226 within the color conversion matrix 225 that is directed at angles lower than total internal reflection critical angle at the boundary with the low-index material layer 235 may exit into the low-index material layer 235 and, upon traversing the low-index material layer 235, into the color filter layer 220 and further into the first substrate 205. The closer the low-index material layer 235 index is to air, a higher percentage of the emission will cross the first substrate 205 and exit into the air. In the ultimate case when low-index material layer index is 1.0 (e.g., there is an air gap), all of the light that exits into the low-index material layer may cross the first substrate 205 without being trapped.

[0044] Emission from the quantum dots 226 within the color conversion matrix 225 that is at higher than total internal reflection critical angle will be reflected back into the color conversion matrix 225. The emissions may be recycled within the color conversion matrix 225 by experiencing scattering with a likelihood of acquiring a more favorable light ray trajectory, such that emission may exit into the low-index material layer 235 on the second, or third, and so-on bounce, resulting in higher optical efficiency for the color converting apparatus 200.

[0045] In order to improve recycling within the color converting cell 245 and the color converting apparatus 200, the plurality of walls 219 may be reflective to encourage diffuse reflection (e.g., where the reflection has a spread in the reflected light angles). The diffuse character of the reflection may further mix and absorb the blue light from the backplane emitter (e.g., adjacent and/or within the second substrate). The mix may allow a lower color conversion matrix 225 thickness or a lower concentration of quantum dots 226 within the color conversion matrix 225. The diffuse character of the reflection from the reflective portion 215 of the plurality of walls 219 may also contribute to the recycling of light rays TIR reflected from the low-index material layer 235, working, in addition to the scattering particles 228, within the color conversion matrix 225 to alter the ray trajectories.

[0046] To increase recycling, each of the plurality of walls 219 comprises a reflective portion 215 spanning the color conversion matrix 225, the low-index material layer 235 and a portion of the color filter 220. In this regard, the reflective portion 215 may comprise a major portion of the surface area of the wall 219 facing the color converting cell 245.

[0047] The reflective portion 215 of the plurality of walls 219 may be formed with different components. In some embodiments, the reflective portion 215 comprises a reflective metal disposed about the plurality of walls 219, while in other embodiments the reflective portion 215 extends internal to the plurality of walls 219.

[0048] The plurality of walls may have a wall thickness. The wall thickness may be desired to be large enough to prevent cross talk between adjacent color conversion cells (see e.g., illustrated wall thickness “TRP” in FIG. 3), while being small enough to maximize the active area of the color converting cells 245. In some embodiments, the wall thickness may be between 5-100 microns. In some embodiments, the wall thickness may be about 10 microns. [0049] In an embodiment, the reflective portion 215 of the plurality of walls 219 may comprise a polymer material filled with light scattering particles. In this regard, the light scattering particles may have a refractive index different than the refractive index of the polymer. The polymer may have a refractive index between about 1.41 to about 1.6. In some embodiments, the light scattering particles may have a refractive index significantly higher than the polymer, for example the light scattering particles may have a refractive index between about 2.2 to 2.8. Example light scattering particles may be titanium dioxide (TiCh), zirconium dioxide (ZrCh), barium titanate (BaTiCh) or similar compounds. In some embodiments, the reflective portion 215 of the plurality of walls 219 may comprise up to 40% light scattering particles by weight, and may have a reflectivity of about 79% at a thickness of 20 microns.

[0050] In other embodiments, the light scattering particles may have a refractive index significantly lower than the polymer, for example, hollow glass particles, which may have a refractive index of about 1.5.

[0051] In some embodiments, the reflective portion 215 of the plurality of walls 219 may be photo imageable, and thus, photolithography tools may be used to pattern the plurality of walls 219.

[0052] In some embodiments, a polymer may be a resin. In this regard, in some embodiments, a UV or thermally curable resin may be filled with the light scattering particles. In some embodiments, micro-imprinting may be used to pattern and position the plurality of walls 219. However, etching may be required to remove any residual layer of resin positioned on the second substrate 240.

[0053] In another example embodiment, the reflective portion 215 of the plurality of walls 219 may be formed from a polymer material filled with metal particles. In some embodiments, an ink filled with metal may be utilized to create the desired reflectivity, for example a vacuum metallic pigment such as Brenda-Lutz SPLENDAL by Sun Chemical or Decomet from Schlenk. In some embodiments, the polymer filled with metal particles may be compatible with 3D printing and/or other printable electronics applications. In some embodiments, the metal particles may be silver or aluminum nanoparticles. In some embodiments, photolithography may be utilized with the polymer filled with metal particles to form the reflective portion 215 of the plurality of walls 219.

[0054] In another example embodiment, the plurality of walls 219 may be formed of a polymer material, where silver nanoparticles have been precipitated in the volume of the polymer under illumination and assembled into a highly reflective layer at the surface of the plurality of walls 219.

[0055] In another example embodiment, the plurality of walls 219 may be formed by coating a polymer wall with a thin layer of a reflective layer. In some embodiments, the polymer may be a 3D printable polymer which may be receptive to electroless plating. In some embodiments, a thin coat of metallic silver (or other high reflective metal layers) may be coated onto the polymer walls formed by photolithography via electroless plating. Alternatively, in some embodiments, functionalized metal nanoparticles or metal-oxide nanoparticles may be chemically coupled (e.g., EDC coupling) to the polymer walls (e.g., only polymer, polymer filled with metal particles, polymer filled with light scattering particles, etc.).

[0056] Notably, in some embodiments, it is undesirable to have the reflective portion directly contact the first substrate due to ambient light reflection on the surface. To prevent ambient light reflection each of the plurality walls 219 comprise an absorption portion 210. The absorption portion 210 functions as a light blocking layer. In some embodiments, the absorption portion 210 may appear black. In some embodiments, the absorption portion 210 may be thin. In this regard, the absorption portion 210 spans only a smaller portion of the color filter 220.

[0057] In some embodiments, the absorption portion 210 may have less than 10% reflectivity, less than 5% reflectivity, or even less than 1% reflectivity.

[0058] In some embodiments, the absorption portion 210 may be a black matrix formed from a black photoresist material, for example photopolymers containing carbon black and/or manganese oxide. However, many black photoresist materials may require a thickness of several microns to achieve the desired light blinking properties, which in turn reduces the size of the reflection portion 215 thereby decreasing the amount of recycling.

[0059] In other embodiments, the absorption portion 210 may be formed from a dark mirror deposited and patterned on the first substrate 205. In some embodiments, dark mirrors may have a thickness of less than 300 nano meters. In some embodiments, the absorption portion 210 may comprise an interference filter and an opaque metal layer. The interference filter may be structured such as to null any reflection from the opaque metal layer. An example dark mirror is a metal-dielectric single cavity structure, or a metal-dielectric double cavity structure using chromium and chromium oxide, or chromium oxynitride. In further examples, a dark mirror may be formed through a combination of a black matrix resist and a physical vapor deposition containing either a metal layer, or a combination of metal and dielectric layers.

[0060] Other example configurations of dark mirrors may be similar to those used in photomasks for semiconductors, and optical apertures for optical systems. In some embodiments, the dark mirror may be formed utilizing physical vapor deposition. In some embodiments, black chrome mirrors may be used such as are used in photomasks for semiconductors, while in other embodiments aluminum metal with a two-cavity dark mirror using silicon monoxide (SiO), silicon dioxide (SiCh) or aluminum oxide (AI2O3) may be used as the dielectric with a thin Chromium reflector. [0061] In another example embodiment, the absorption portion 210 may be formed from tungsten. While in still another example embodiment, the absorption portion 210 may be formed from an evaporated layer of a metal dielectric alloy. In still another embodiment, the absorption portion 210 may be formed from hydrogenated SiGe alloy.

[0062] In some embodiments, the exposed metal portion may be used as a seed layer for electrolysis plating or electroplating to form the reflective portion 215 of the plurality of walls 219. In other embodiments, and additional metal layer may be deposited on top of the dark mirror, where the additional metal layer is compatible with the reflective portion 215. For example, the Al opaque layer in a black aluminum dark mirror can be used for plating an aluminum, or a dark mirror can be formed with a nickel reflector, and the nickel used as a seed for electroless Ni deposition.

[0063] To form a display, more than one color conversion apparatus 200 may be positioned adjacent where each of the color converting cells shares one or more of the plurality of walls. FIG. 3 illustrates a color converting apparatus 300 comprising three color cells. Each of the three color cells may be divided by corresponding walls, and bound between a first substrate 205 and a second substrate 240. Although described here as being a first color cell 245a, a second color cell 245b, and a third color cell 245c, the order of the color cells is interchangeable, and may be patterned depending on the desired outcome.

[0064] In some embodiments, the first color cell 245a may comprise a diffusion matrix 229 comprising a plurality of light scattering particles 228. In some embodiments, the diffusion matrix 229 may comprise a polymer with inclusions. In some embodiments, the first color cell 245a may additionally comprise a first color filter 220a disposed above the diffusion matrix 229. In some embodiments, the first color cell 245a may be configured to expel blue light. In this regard, no quantum dots or other luminescent emitter is necessary to change the color of the emitted light (e.g., the LED may be a blue light LED). However, the light scattering particles 228 may diffuse the light such that the emitted light is consistent with the light emitted from the second color cell 245b and the third color cell 245c, as red and green quantum dots may be highly scattering.

[0065] In some embodiments, each of the second color cell 245b and the third color converting cell 245c may reflect the structure of the color converting apparatus 200 as discussed with reference to FIG. 2. However, the second color cell 245b may comprise a color converting matrix comprising a first color quantum dot (e.g., red) and a corresponding color filter 220b, and the third color cell 245c may comprise a second color quantum dot (e.g., green) and a corresponding color filter 220c.

[0066] As discussed, the absorption portion 210 of the plurality of walls 219 prevents ambient light reflection into the color cells. In some embodiments, as illustrated the absorption portion 210 may additionally prevent cross talk between the color cells (e.g., the first color cell 245a and the second color cell 245b, or the second color cell 245b and the third color cell 245c).

[0067] FIGs. 4A-B illustrate reflectance percentage through a glass substrate (e.g., first substrate) coated with an absorption portion 210 in air for a range of angles of incidence from 0 to 60° for different wavelengths of light. FIG. 4A illustrates a black aluminum dark mirror coating as the absorption portion, and FIG. 4B illustrates a two-cavity black chrome coating. As illustrated, the two-cavity black chrome coating produces a lower reflectance over a broad range of wavelengths regardless of the angle of incidence, while the black aluminum dark mirror provides a low reflectance for certain angles of incidence between wavelengths of about 400-600 nm.

Example Flowchart(s)

[0068] FIG. 5 is a flowchart illustrating an example method 400 for forming a color converting apparatus in accordance with some embodiments discussed herein. At operation 402, a plurality of walls are formed on a first substrate. At operation 404, a color filter is formed on the first substate between the plurality of walls. At operation 406, a low-index material layer is formed on the color filter. At operation 408, a luminescent layer (e.g., with luminescent emitter particles) is formed on the low-index material layer. At operation 410, a second substrate is laminated to the plurality of walls. Additional steps may be included that are not shown, for example forming an encapsulation layer to protect the luminescent layer, another encapsulation layer to protect OLED emitters, a planarization layer, or an adhesive layer for lamination.

[0069] FIGs. 6-10 are example flowcharts for forming portions of the color converting apparatus. FIG. 6 is a flowchart illustrating operation 402 of FIG. 5 for forming a plurality of walls. At operation 412, an absorption portion of the wall is formed. At operation 414, a reflective portion of the wall is formed on the absorption portion. FIG. 7 is a flowchart illustrating operation 412 of FIG. 6 for forming the absorption portion of the wall. At operation 416, an absorption material is patterned on to the first substrate. In some embodiments, the absorption material may be patterned via photolithography, 3D printing, coating, or other application. Optionally, at operation 418, an additional seed layer may be deposited onto the absorption material. Operation 418 may be utilized when the absorption portion is not compatible with the reflective portion.

[0070] FIGs. 8-10 are flowcharts illustrating operation 414 for forming the reflective portion of the wall. FIG. 8 illustrates a first method 414’ of forming the reflective portion. At operation 420, a polymer is mixed with light scattering particles. At operation 422, the mixture of polymer and light scattering particles is applied to the absorption portion via photolithography. In some embodiments, the photolithography may pattern apply the mixture, while in other embodiments the photolithography may coat the mixture onto the absorption portion. Optionally, at operation 424, residual mixture may be etched off, or otherwise removed from undesired portions.

[0071] FIG. 9 illustrates another method 414” of forming the reflective portion. At operation 430, a polymer is mixed with metal particles. At operation 432, the mixture of polymer and metal particles is applied to the absorption portion via photolithography. In some embodiments, the photolithography may pattern apply the mixture, while in other embodiments the photolithography may coat the mixture onto the absorption portion. Optionally, at operation 434, residual mixture may be etched off, or otherwise removed from undesired portions.

[0072] FIG. 10 illustrates another method 414’” of forming the reflective portion. At operation 440, a base portion of the wall is formed on the absorption portion. In some embodiments, the base portion may be a polymer or other printable material. At operation 442, reflective nanoparticles are coated onto the base portion.

[0073] Notably, the above operations for FIGs. 6-10, while described in a certain order, may be performed in a different order and/or some of the operations may be performed simultaneously.

Conclusion

[0074] It will therefore be readily understood by those persons skilled in the art that the present disclosure is susceptible of broad utility and application. Many embodiments and adaptations of the present disclosure other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present disclosure and the foregoing description thereof, without departing from the substance or scope of the present disclosure. Accordingly, while the present disclosure has been described herein in detail in relation to its preferred embodiment s), it is to be understood that this disclosure is only illustrative and exemplary and does not otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements.

Claims

WHAT IS CLAIMED:

1. An apparatus comprising: a color conversion cell comprising: a low-index material layer; a color filter disposed adjacent the low-index material layer; and a color conversion matrix comprising a plurality of quantum dots and a medium, wherein the color conversion matrix is adjacent one of either the low-index material layer or the color filter; a first wall and a second wall, wherein each of the first wall and the second wall comprise a reflective portion and an absorption portion, and wherein the color conversion cell is bound between the first wall and the second wall; a first substrate positioned adjacent to the color conversion cell, wherein the first substrate extends between the absorption portion of the first wall and the absorption portion of the second wall; and a second substrate positioned adjacent to the color conversion matrix of the color conversion cell, wherein the second substrate extends between the reflective portion of the first wall and the reflective portion of the second wall.

2. The apparatus of claim 1, wherein the absorption portion comprises a dark mirror.

3. The apparatus of claim 2, wherein the dark mirror comprises an interference filter and an opaque metal layer.

4. The apparatus of claim 3, wherein the opaque metal layer comprises chromium and either chromium oxide or chromium oxynitride.

5. The apparatus of claim 3, wherein the opaque metal layer comprises aluminum.

6. The apparatus of claim 1, wherein the absorption portion comprises a black polymer containing a black pigment.

7. The apparatus of claim 6, wherein the black pigment comprises carbon black.

8. The apparatus of any of claims 1-7, wherein the absorption portion defines a thickness of less than 300 nanometers.

9. The apparatus of any of claims 1-8, wherein the absorption portion comprises a metaldielectric structure.

10. The apparatus of any of claims 1-9, wherein the reflective portion comprises embedded particles.

11. The apparatus of any of claims 1-9, wherein the reflective portion comprises a polymer comprising chemically coupled metal nanoparticles.

12. The apparatus of any of claims 1-9, wherein the reflective portion comprises a reflective metal.

13. The apparatus of any of claims 1-12, wherein the first wall defines a first wall thickness and the second wall defines a second wall thickness, wherein the first wall thickness and the second wall thickness are about 10 microns.

14. A color converting apparatus comprising: a first color converting cell comprising: a low-index material layer; a color filter disposed adjacent the low-index material layer; and a color conversion matrix comprising a plurality of quantum dots and a medium, wherein the color conversion matrix is adjacent one of either the low-index material layer or the color filter; a second color converting cell comprising: a diffusion matrix comprising a plurality of light scattering particles; and a second color filter disposed adjacent the diffusion matrix; a plurality of walls, wherein each of the plurality of walls comprise a reflective portion and an absorption portion, wherein the first color converting cell is bound between a first wall and a second wall, and the second color converting cell is bound between the second wall and a third wall; a first substrate positioned adjacent the first color converting cell and the second color converting cell, wherein the first substrate extends between the absorption portion of the first wall and the absorption portion of the third wall; and a second substrate positioned adjacent the first color converting cell and the second color converting cell, wherein the second substrate extends between the reflective portion of the first wall and the reflective portion of the third wall.

15. The color converting apparatus of claim 14, wherein the absorption portion comprises a dark mirror.

16. The color converting apparatus of claim 15, wherein the dark mirror comprises an interference filter and an opaque metal layer.

17. The color converting apparatus of claim 16, wherein the opaque metal layer comprises chromium and either chromium oxide or chromium oxynitride.

18. The color converting apparatus of claim 14, wherein the absorption portion comprises a black polymer containing a black pigment.

19. The color converting apparatus of any of claims 14-18, wherein the absorption portion defines a thickness of less than 300 nanometers.

20. The color converting apparatus of any of claims 14-19, wherein the reflective portion comprises embedded particles.

21. The color converting apparatus of any of claims 14-20, wherein the reflective portion comprises a polymer comprising chemically coupled metal nanoparticles.

22. The color converting apparatus of any of claims 14-21, wherein the plurality of walls each define a wall thickness, and wherein the wall thickness is about 10 microns.

23. The color converting apparatus of any of claims 14-22 further comprising: a third color converting cell, the third color converting cell comprising: a second low-index material layer; a third color filter adjacent the second low-index material layer; and a third color conversion matrix comprising a third plurality of quantum dots and a second medium, wherein the third color conversion matrix is disposed adjacent one of the second low-index material layer or the third color filter; wherein the third color converting cell is bound by the third wall and a fourth wall, and wherein the first substrate extends to the absorption portion of the fourth wall, and wherein the second substrate extends to the reflective portion of the fourth wall.

24. A method of forming a color converting apparatus, the method comprising: forming at least a first wall and a second wall on a first substrate, each of the first wall and second wall comprising an absorption portion and a reflective portion; forming at least one color converting cell on the first substrate between the first wall and the second wall, the at least one color converting cell comprising: a low-index material layer; a color filter adjacent the low-index material layer; and a photoresist layer positioned adjacent one of either the low-index material layer or the color filter; and securing a second substrate to the reflective portion of each of the first wall and the second wall.

25. The method of claim 24, wherein the absorption portion comprises an interference filter and an opaque metal layer.

26. The method of claim 24, wherein the absorption portion comprises a photomask.

27. The method of any of claims 24-26, wherein the reflective portion is formed via photolithography .

28. The method of any of claims 24-26, wherein the reflective portion comprises an electroplated polymer.

29. The method of any of claims 24-26, wherein the reflective portion comprises a polymer mixed with metal particles.

30. The method of any of claims 24-26, wherein the reflective portion comprises a polymer mixed with light scattering particles.

31. A display comprising: a color cell comprising: a low-index material layer; a color filter adjacent the low-index material layer; and a color conversion matrix comprising a plurality of quantum dots and a medium, wherein the color conversion is adjacent one of either the low-index material layer or the color filter; a first wall and a second wall, wherein each of the first wall and the second wall comprise a reflective portion and an absorption portion, and wherein the color cell is bound between the first wall and the second wall; a first substrate positioned adjacent the color cell, wherein the first substrate extends between the absorption portion of the first wall and the absorption portion of the second wall; and a second substrate positioned adjacent the color conversion matrix of the color cell, wherein a light source extends between the reflective portion of the first wall and the reflective portion of the second wall.