Microlens array sheet using quantum dot composite

Abstract

The present invention relates to a microlens array sheet of ultra-high resolution using quantum dots and a method for manufacturing same, for implementing an ultra-high resolution RGB display, and a color-conversion microlens array sheet according to one embodiment of the present invention is formed by first creating a barrier structure to determine the diameter of the lenses and the distance between adjacent lenses, and then filling empty spaces between the barriers with a microlens-shaped structure containing quantum dots.

Description

Microlens array sheet using quantum dot complex

[0001] The present invention relates to a quantum dot micro lens array sheet and a method for manufacturing the same, and more particularly, to a micro lens array sheet and a method for manufacturing the same that can achieve process simplification in a field where the introduction of color conversion using micro lenses and color filters is required simultaneously.

[0002]

[0003] Color conversion technology is one of the key technologies for implementing full-color displays, image sensors, etc.

[0004] Organic dyes and fluorescent substances have generally been used as color conversion materials, but organic dyes have low thermal stability and exhibit bleaching phenomena, and fluorescent substances have the disadvantage of having large particles, which results in a large light scattering effect and makes fine patterning difficult.

[0005] Recently, quantum dots with high color purity have been attracting attention as color conversion materials, but there are still problems such as low external quantum efficiency of the material itself and difficulty in directly micro-patterning the device using only a quantum dot solution.

[0006] Conventional color filters are mainly manufactured through a photolithography process that selectively irradiates light through a patterned mask to form layers only at desired locations, or by printing quantum dot ink at desired locations.

[0007] However, in the case of the lithography process, separate masks are required for each color, the equipment configuration is complex, and additional masks must be produced for each color and pattern, which is a disadvantage.

[0008] In addition, when printing quantum dot ink, it is possible to achieve simplification of equipment configuration compared to the existing lithography method, but there is a problem that the QD thin film is not formed uniformly due to the coffee ring effect when the solvent in which the quantum dots are dispersed evaporates.

[0009] Furthermore, when quantum dot ink is dispersed in a polymer, printed, and cured, the ligand material surrounding the quantum dots can interfere with the curing of the polymer during the polymer curing process, which has been a limiting factor in the production of high-concentration quantum dot complexes. Furthermore, the polymer material mixed with such ligands can sometimes block the nozzles required for the precise printing process, causing ongoing problems in terms of process continuity.

[0010]

[0011] The present invention is intended to solve the problems of the above-described prior art, and relates to an ultra-high-resolution micro lens array sheet using quantum dots and a method for manufacturing the same to implement an ultra-high-resolution RGB display.

[0012] Furthermore, the present invention aims to propose material and process technologies for manufacturing and commercializing micro lenses using high-concentration QD complexes.

[0013]

[0014] In order to achieve the above purpose, a micro lens array sheet according to one embodiment of the present invention first forms a barrier structure to determine the diameter of a lens and the distance between adjacent lenses, and the empty space between the barriers is filled with a micro lens-shaped structure containing quantum dots.

[0015] Additionally, a micrometer-scale color-conversion structure array in the form of a micro lens is fabricated and subsequently positioned on a single-color, ultra-high-resolution LED array.

[0016] A microlens using a quantum dot complex according to one embodiment of the present invention comprises: a cured polymer having a quantum dot material dispersed therein; and a capping organic material forming a bond around the cured polymer by a thioether functional group.

[0017] In one embodiment, the capping material is C3~C 20 It is composed of a carbon chain,

[0018] The above thioether functional group may be located at the end of the carbon chain.

[0019] In one embodiment, the capping material may include an ester group located in the middle of the carbon chain.

[0020] According to one embodiment, the capping material may be a thioether group of the following [chemical formula 1] bonded to a cured polymer of the quantum dot material.

[0021] [Chemical Formula 1]

[0022]

[0023] According to one embodiment, the micro lens may have a hemispherical cross-section and guide the light path so that light that has left the light-emitting area is not diffused.

[0024] According to one embodiment, the quantum dot may include a core-shell structure or an alloy structure, and the quantum dot may include at least one selected from the group consisting of InP / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, CdSe / CdSx(Zn1-yCdy)S / ZnS, CdSe / CdS / ZnCdS / ZnS, InP / ZnS, InP / Ga / ZnS, InP / ZnSe / ZnS, PbSe / PbS, CdSe / CdS, CdSe / CdS / ZnS, CdTe / CdS, CdTe / ZnS, CuInS2 / ZnS, and Cu2SnS3 / ZnS.

[0025] According to one embodiment, the curable polymer may have transparent properties before curing and black matrix properties after curing.

[0026] In one embodiment, the micro lens may be manufactured by a printing method.

[0027] In one embodiment, the microlenses may have a pitch length of 10 μm to 100 μm.

[0028]

[0029] According to another embodiment of the present invention, a microlens array sheet using a quantum dot complex includes: a base sheet; a barrier structure formed on the base sheet and defining a space in which microlenses are to be positioned; and a plurality of quantum dot microlenses formed in a space between side walls of the barrier structure, wherein the quantum dot microlenses may include one or more microlenses using the quantum dot complex according to an embodiment of the present invention.

[0030] In one embodiment, the barrier structure may be formed using a printing method.

[0031] In one embodiment, the barrier structure may be in the form of a black matrix that absorbs light.

[0032] In one embodiment, the cross-sectional height of the micro lens may be higher than the height of the barrier structure.

[0033] In one embodiment, the micro lenses may be formed in multiples and may include a quantum dot material that emits a different wavelength from the color conversion lens in an adjacent area.

[0034] In one embodiment, the micro lens array sheet may include at least one lens that guides only the light path using an ultraviolet-curable polymer that does not include quantum dots among a plurality of micro lenses.

[0035]

[0036] According to another embodiment of the present invention, a method for manufacturing a microlens array sheet using a quantum dot complex includes the steps of: preparing a substrate having a base sheet formed thereon; printing a barrier structure on the base sheet to define a space where a plurality of microlenses are to be formed; preparing a quantum dot microlens material to which a capping organic material is bound by replacing a capping ligand bound to a curable polymer having a quantum dot material dispersed therein with an organic material including a thiol group; forming one or more microlenses in an empty space between barrier structures on the base sheet using the microlens material; curing the curable polymer by applying light to the microlenses; and separating and removing the substrate from the base sheet.

[0037] According to one embodiment, in the step of preparing the quantum dot microlens material, the organic material including the thiol group is C3~C 20 It may be composed of a carbon chain, has a thiol group at the terminal, and includes an ester group located in the middle of the carbon chain.

[0038] According to one embodiment, the organic material including a thiol group in the step of preparing the quantum dot microlens material may include a material of the following [chemical formula 2].

[0039] [Chemical Formula 2]

[0040]

[0041]

[0042] According to one embodiment, the step of printing the barrier structure may be a dispensing process or an electrohydrodynamic printing process, and the step of forming the micro lens may be a step of printing the micro lens using an EHD printing process.

[0043]

[0044] According to another embodiment of the present invention, a light-emitting display array including a micro-lens array sheet using a quantum dot complex comprises: a display array emitting light of a single wavelength; one or more micro-lens array sheets positioned on the display array, wherein the micro-lens array sheets include: a substrate; a barrier structure including a curable polymer on the substrate; and one or more micro-lenses using a quantum dot complex according to an embodiment of the present invention formed in a space between side walls of the barrier structure.

[0045]

[0046] A micro lens array sheet according to one embodiment of the present invention can be positioned on an LED array of various sizes having a single blue color when manufacturing a full-color display to implement three RGB colors, thereby achieving simplification of the process method compared to a method of manufacturing and driving LEDs of three different colors.

[0047] In addition, by using an ultraviolet curing method rather than the conventional thermal curing method, the color conversion materials inside the lens are uniformly distributed after curing, so a uniform color conversion effect can be obtained.

[0048] Additionally, depending on the process method, it is possible to produce lens arrays on the scale of tens of micrometers, making it possible to achieve full-color display when producing ultra-high-resolution displays.

[0049] In addition, since the micro lens array sheet can be manufactured on a flexible substrate, it can be attached to a curved display, and if an adhesive surface is formed on one side of the flexible substrate, it can be attached to various locations to confirm the color transition effect.

[0050] In addition, the micro lens array manufactured using the method proposed in the present invention has the advantage of being able to manufacture micro lenses that exhibit homogeneous luminescence characteristics even when manufactured using high-concentration quantum dot ink, being able to manufacture them by reducing the lens radius to a scale of tens of micrometers, and increasing industrial applicability because the injection nozzle is not blocked even after repeated printing processes.

[0051]

[0052] FIG. 1 is an exemplary drawing for explaining a method for manufacturing a quantum dot microlens according to one embodiment of the present invention.

[0053] Figure 2 is an actual image of the micro lens formation process through an EHD printing process on a barrier structure.

[0054] Figure 3 is an example of a micro lens array sheet manufactured using a printing process.

[0055] Figure 4 is an example of a microlens array sheet being manufactured using a conventional method, in which an issue of nozzle occlusion or poor dispersibility of quantum dots occurs, resulting in an inhomogeneous microlens array sheet being manufactured, and an actual image showing its fluorescence characteristics.

[0056] Figure 5 is a drawing showing an example of a ligand material surrounding a quantum dot material when manufactured according to a conventional method, and is a structure in which a CdSe quantum dot material is capped with oleic acid as a ligand.

[0057] FIG. 6 is a drawing illustrating a process of replacing a ligand material surrounding a quantum dot material with an organic capping material containing a thiol group in a manufacturing method according to one embodiment of the present invention.

[0058] FIG. 7 shows an inhomogeneous emission image (left) of a quantum dot microlens manufactured using oleic acid as a ligand material surrounding a quantum dot material and NOA 61 (commercial name) as a polymer material according to a conventional method, and a uniform emission image (right) of a quantum dot microlens manufactured according to an embodiment of the present invention, which is different only in that the ligand is replaced with an organic capping material according to the method described in FIG. 6.

[0059] Figure 8 is a schematic diagram illustrating each step of a method for manufacturing a microlens according to one embodiment of the present invention. It can be confirmed that the structure in which the capping ligand of a quantum dot material is formed with conventional oleic acid is replaced by butyl 3-mercaptopropionate as a capping organic material.

[0060] FIG. 9 is a microscope image (left two images) of a non-uniform quantum dot microlens array containing oleic acid as a capping ligand manufactured by a conventional printing method, and a microscope image (right two images) of a uniform quantum dot microlens array manufactured after treatment with a capping organic material according to an embodiment of the present invention.

[0061] FIG. 10 is a graph showing the experimental results of luminescence characteristics of a uniform quantum dot microlens manufactured after treatment with a capping organic material according to one embodiment of the present invention.

[0062] Figure 11 is a graph showing the atomic bonding of a capping organic material included in a uniform quantum dot microlens material manufactured after treatment with the capping organic material according to one embodiment of the present invention. It can be confirmed that C=O and SH bonds are included.

[0063] FIG. 12 is a graph comparing and analyzing the red and green luminescence characteristics of a non-uniform quantum dot microlens containing oleic acid as a capping ligand manufactured by a printing method using a conventional method and a uniform quantum dot microlens manufactured after treatment with a capping organic material according to an embodiment of the present invention.

[0064] FIG. 13 is a microscope image confirming the luminescence characteristics of a uniform quantum dot microlens array manufactured after treatment with a capping organic material according to one embodiment of the present invention.

[0065] FIGS. 14 and 15 are microscope images confirming the red and green luminescence characteristics of a uniform quantum dot microlens array manufactured after treatment with a capping organic material according to one embodiment of the present invention.

[0066] Figure 16 is an image showing a uniform quantum dot microlens array manufactured through a printing method of ink after treatment with a capping organic material according to one embodiment of the present invention, in which a homogeneous lens is formed while varying the quantum dot concentration in the ink, thereby exhibiting consistent luminescence characteristics. It can be confirmed that a homogeneous lens is formed and exhibits consistent luminescence characteristics even when the concentration is increased from 50 mg / ml to 150 mg / ml.

[0067] FIG. 17 shows various graphic or character images produced using a uniform quantum dot microlens array manufactured after treatment with a capping organic material according to one embodiment of the present invention.

[0068] FIG. 18 is a graph showing the luminescence characteristics measured when a homogeneous lens is formed by varying the quantum dot concentration in the ink in a uniform quantum dot microlens array manufactured through a printing method of ink after treatment with a capping organic material according to one embodiment of the present invention.

[0069] FIG. 19 is a graph showing the measurement of luminescence characteristics of micro lenses manufactured by varying the quantum dot concentration in ink after treatment with a capping organic material according to one embodiment of the present invention, applied to a pure blue wavelength.

[0070] FIG. 20 is an image showing the luminescence characteristics of a uniform quantum dot microlens manufactured through a printing method using ink formed at a high concentration of 150 mg / ml after treatment with a capping organic material according to one embodiment of the present invention.

[0071] FIGS. 21 to 23 are microscope images showing the luminescence characteristics of a color conversion lens including quantum dots formed between the grids of a barrier formed by EHD printing a PDMS material according to an embodiment of the present invention. FIG. 21 clearly illustrates the steps of each process, and FIG. 22 confirms that even when a lens having a pitch size of 80 μm is implemented, uniform luminescence characteristics are exhibited, and FIG. 23 clearly reveals the height of the barrier and the shape of the micro lens formed between the grids according to an embodiment of the present invention, as well as its luminescence characteristics.

[0072] FIG. 24 is an image showing a color change as light is emitted from an array by applying heat to an electrode on which light-emitting elements are arranged using a micro lens according to one embodiment of the present invention.

[0073]

[0074] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. When designating components in each drawing, it should be noted that, where possible, identical components are given identical reference numerals even if they appear in different drawings. Furthermore, when describing embodiments of the present invention, detailed descriptions of known components or functions will be omitted if they are deemed to hinder understanding of the embodiments of the present invention.

[0075] FIG. 1 is an exemplary drawing for explaining a method for manufacturing a color conversion micro lens according to one embodiment of the present invention, and FIG. 2 is an actual image taken of a lens formation process through an EHD printing process on a barrier structure.

[0076] Referring to FIGS. 1 and 2, to manufacture a color conversion microlens according to one embodiment of the present invention, a substrate on which a sheet array will be positioned is first prepared. This substrate may be manufactured on a rigid, flat substrate and applied to a flat panel display, or a plastic substrate may be fixed to a fixed substrate and then removed after a subsequent manufacturing process to produce a flexible sheet.

[0077] Next, a barrier structure is fabricated using a printing process. The barrier structure can be manufactured by varying the width and spacing between barriers to control the desired lens diameter and the distance between adjacent lenses. Furthermore, the barrier can be manufactured with increased thickness through repeated printing to increase the height of the lens. Depending on the display resolution and required size, a pneumatic dispensing process can be utilized, or for high-resolution micro LED displays, an electrohydrodynamic printing process can be utilized. This allows for easy control of the barrier width from several micrometers to hundreds of micrometers.

[0078] In the case of barrier structure materials, as described below, by utilizing UV-curable materials, such as polymer materials that constitute the mixture of microlens materials, patterning can be performed to the desired size without the effect of height reduction due to solvent evaporation after curing. Furthermore, by utilizing materials that are transparent during printing but change color upon curing and whose color absorbs light after UV curing, the production of a barrier in the form of a black matrix can be achieved.

[0079] Next, microlenses are printed into the voids of the barrier structure. In the present invention, quantum dots are uniformly dispersed in a polymer material that is cured with light in the ultraviolet wavelength range, and then cured to produce a color-conversion layer of uniform concentration in the form of a lens.

[0080] At this time, to achieve the shape of the lens, self-assembled monolayer (SAM) processing can be performed to reduce the surface energy of the substrate and barrier structure, thereby reducing the adhesion between the substrate and the microlens material. The material constituting the lens uses ink in which quantum dots, which are materials that emit light of a specific wavelength when light is transmitted, are dispersed in an ultraviolet-curable material. This allows the shape of the lens to be maintained without changing in size even after curing, and by introducing the lens shape, the height of the color conversion structure is increased compared to simply manufacturing it in a thin film form in a barrier of the same thickness, thereby achieving a higher color conversion rate and facilitating the external emission of light whose wavelength has been converted.

[0081] A quantum dot solution (QD) may be a state in which quantum dots are dispersed in a solvent. Quantum dots may include semiconductors of groups II-VI, III-V, IV-VI, IV, or mixtures thereof, and can absorb light at a certain wavelength and emit light at a wavelength different from the wavelength of the absorbed light, thereby converting the color of the absorbed light. For example, semiconductor materials constituting quantum dots include InP, Si, Ge, Sn, Se, Te, B, C, P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InAs, InSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdxSeySz, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuInS2, Cu2SnS3, CuBr, CuI, Si3N4, Ge3N4, Al2O3, CIGS, CGS, (ZnS)y(CuxSn1-xS2)1-y (wherein x and y are each real numbers less than or equal to 1), and mixtures of these semiconductors. In addition, the quantum dots may have a core / shell structure or an alloy structure. The quantum dots having a core / shell structure or an alloy structure may be, but are not limited to, InP / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, CdSe / CdSx(Zn1-yCdy)S / ZnS, CdSe / CdS / ZnCdS / ZnS, InP / ZnS, InP / Ga / ZnS, InP / ZnSe / ZnS, PbSe / PbS, CdSe / CdS, CdSe / CdS / ZnS, CdTe / CdS, CdTe / ZnS, CuInS2 / ZnS, or Cu2SnS3 / ZnS.

[0082] The solvent contained in the quantum dot solution (QD) may be a volatile organic solvent with a low boiling point. For example, the solvent may be a solution with chemical properties that evaporate after a certain period of time at room temperature. The solvent may be, but is not limited to, a toluene solution.

[0083] The curable polymer may be a polymer material that is cured by light of a certain wavelength and thus has a fixed shape. For example, the curable polymer may be a UV-curable polymer that is cured by ultraviolet light, but is not limited thereto. In addition, since the curable polymer forms a microlens together with a quantum dot solution (QD), it is preferable that it not have a specific color. Furthermore, since high temperatures may occur depending on the operating environment, it is preferable that it have thermal stability. For example, the curable polymer may be a polymer material that is transparent and has thermal stability. In addition, the curable polymer may be a liquid at room temperature before curing and may have good miscibility with the quantum dots. In addition, the curable polymer may be a polymer material that has adhesive properties. Since the curable polymer has adhesive properties, the quantum dot-curable polymer resin applied in the solution process described below temporarily maintains a hemispherical shape. Here, the curable polymer may be, but is not limited to, Norland Optical Adhesive 61 (“NOA 61”) or Norland Optical Adhesive 63 (“NOA 63”) commercially available from Norland Products.

[0084] Quantum dot solution (QD) and curable polymer can be mixed at a certain ratio. A high QD concentration results in high light conversion efficiency, but aggregation between quantum dots can occur, hindering the application of the solution process. Furthermore, a low QD concentration can facilitate the solution process, but lower light conversion efficiency can lead to a dilution of the unique characteristics of the color conversion lens. Therefore, the quantum dot solution (QD) and curable polymer are mixed at the following appropriate ratio.

[0085] The quantum dot solution (QD) may have different specific weights mixed with the curable polymer depending on the color wavelength to be converted. When the curable polymer is 100 parts by weight, the quantum dot solution (QD) emitting green light and red light may be 2.00 parts by weight to 10.50 parts by weight, 2.50 parts by weight to 10.00 parts by weight, 3.00 parts by weight to 9.50 parts by weight, 3.50 parts by weight to 9.00 parts by weight, 8.50 parts by weight or more, and 4.16 parts by weight to 8.33 parts by weight, respectively.

[0086] The mixed quantum dot solution and curable polymer are stirred at room temperature. The mixed quantum dot solution and curable polymer are stirred at room temperature for a certain period of time to disperse the quantum dots within the curable polymer. For example, the mixed quantum dot solution and curable polymer can be stirred at room temperature for 24 hours, and this stirring process can disperse the quantum dots within the curable polymer.

[0087] The solvent is evaporated from a stirred quantum dot-curable polymer mixture solution to form the quantum dot-curable polymer resin. The stirred quantum dot-curable polymer mixture solution is transferred to a vacuum chamber, a desiccator, to evaporate the solvent contained in the quantum dot solution. As the solvent evaporates, the stirred quantum dot-curable polymer mixture solution can be transformed into a quantum dot-curable polymer resin. The quantum dot-curable polymer resin can be in a state where quantum dots are sufficiently dispersed in the curable polymer to be usable in a solution process.

[0088] Next, the quantum dot-curable polymer resin is printed onto a substrate through a solution process to form a microlens.

[0089] When manufacturing microlenses, a pneumatic dispensing process can be utilized, depending on the lens diameter. Alternatively, by fabricating a lens array as small as tens of micrometers using the EHD printing process, color-shifting structures applicable to ultra-high-resolution displays can be created. Furthermore, lenses can be printed to a desired location based on the location of a previously fabricated barrier structure.

[0090] At the bottom of the micro lens array sheet, a display array that emits short-wavelength light is positioned, and after positioning blue light, which has the shortest wavelength, red light is emitted using a lens containing quantum dots that cause a color transition to red light, and green light is emitted using a quantum dot lens that causes a color transition to green light. In the case of blue light, a transparent lens that does not disperse quantum dots is positioned so that blue light is ultimately emitted, thereby implementing a full-color display.

[0091] Next, the microlens array sheet is removed from the fixed substrate and attached to the desired location. The microlens array sheet can be manufactured on a substrate that does not change shape, such as a glass substrate, and can also be formed on a plastic substrate that is easily bent. Therefore, the manufactured microlens array sheet can be attached to the desired location later and utilized in the form of a color filter. For example, in the case of a microlens array sheet manufactured on a plastic substrate, it is removed from the fixed substrate and attached to the desired location.

[0092] Figure 3 is an example of a micro lens array sheet manufactured using a printing process.

[0093] Referring to FIG. 3, a barrier structure is first formed to determine the diameter of the microlenses and the distance between adjacent lenses, and then a microlens array sheet is manufactured in such a manner that the empty space between the barriers is filled with a structure in the form of a microlens containing quantum dots. Through this configuration, the diameter of the microlenses and the distance between the color conversion layers can be determined.

[0094] According to one embodiment of the present invention, a micro lens array sheet can be used to achieve an effect in which light of a single wavelength (e.g., blue light) emitted from a light source located at the bottom of the micro lens array sheet is converted into light of a different wavelength (e.g., red light, green light) while passing through the lens structure. For example, the light source can be an LED or a micro LED, but is not limited thereto. The lens is configured in an array form and functions as a color conversion color filter in a high-resolution display, and is manufactured in the form of a single sheet on a plastic substrate so that it can be attached to a desired location.

[0095] According to an embodiment of the present invention, since the microlens is formed in a hemispherical shape, the light path is changed by being refracted on the surface of the microlens. When the upper area vertically overlapping each microlens is defined as the light-emitting area of ​​each microlens, the light emitted from the microlens can be refracted on the lens surface so as to be focused on the light-emitting area. In other words, the hemispherical microlens can guide the light path so that the light is focused on the light-emitting area without being diffused outside of the light-emitting area. Accordingly, the hemispherical microlens can prevent color mixing between neighboring pixels.

[0096] A micro lens array sheet according to one embodiment of the present invention may include a lens for setting an optical path.

[0097] A lens for setting an optical path is formed on a microlens array sheet corresponding to an area where blue light is emitted. Here, the microlens for setting an optical path can be produced by printing a transparent curable polymer that does not contain quantum dots into a hemispherical shape through a solution process, and curing the hemispherically printed microlens for setting an optical path. Since the lens for setting an optical path does not contain quantum dots, color conversion of blue light does not occur. Instead, the blue light can be concentrated on an emission area corresponding to an upper area that vertically overlaps the lens for setting an optical path, and the blue light can be prevented from invading the emission areas of other lenses.

[0098]

[0099] Figure 5 illustrates an example of a ligand material surrounding a quantum dot material when manufactured according to a conventional method, and is a drawing showing a structure in which a CdSe quantum dot material is capped with oleic acid as a ligand. The inventors of the present invention sought to resolve the problem that, when using a ligand according to such a conventional method, a printing process for ink containing a high concentration of QD material cannot be applied industrially.

[0100]

[0101] FIG. 6 is a drawing illustrating a process of replacing a ligand material surrounding a quantum dot material with an organic capping material containing a thiol group in a manufacturing method according to one embodiment of the present invention. Hereinafter, a microlens that can be manufactured by replacing the capping ligand of a quantum dot material with the organic capping material proposed in the present invention based on the process of FIG. 6 will be described in detail.

[0102]

[0103] A microlens using a quantum dot complex according to one embodiment of the present invention comprises: a cured polymer having a quantum dot material dispersed therein; and a capping organic material forming a bond around the cured polymer by a thioether functional group.

[0104] FIG. 7 shows an inhomogeneous emission image (left) of a quantum dot microlens manufactured using oleic acid as a ligand material surrounding a quantum dot material and NOA 61 (commercial name) as a polymer material according to a conventional method, and a uniform emission image (right) of a quantum dot microlens manufactured according to an embodiment of the present invention, which is different only in that the ligand is replaced with an organic capping material according to the method described in FIG. 6.

[0105] Oleic acid, as illustrated in Figure 7, has been commonly used as a capping ligand material for conventional quantum dot materials. However, ligands such as oleic acid have been known to impede dispersibility and clog nozzles when manufacturing high-concentration quantum dot inks. The present invention proposes encapsulating quantum dot materials with a capping organic material containing a thioether functional group, as described above.

[0106] Figure 8 is a schematic diagram illustrating each step of a method for manufacturing a microlens according to one embodiment of the present invention. It can be confirmed that the structure in which the capping ligand of a quantum dot material is formed with conventional oleic acid is replaced by butyl 3-mercaptopropionate as a capping organic material.

[0107]

[0108] In one embodiment, the capping material is C3~C 20 It is composed of a carbon chain, and the thioether functional group may be located at the end of the carbon chain. The carbon chain of the capping material may include 3 to 20 carbons, but is not necessarily limited thereto.

[0109] In one embodiment, the capping material may include an ester group located in the middle of the carbon chain.

[0110] According to one embodiment, the capping material may be a thioether group of the following [chemical formula 1] bonded to a cured polymer of the quantum dot material.

[0111] [Chemical Formula 1]

[0112]

[0113]

[0114] FIG. 9 is a microscope image (left two images) of a non-uniform quantum dot microlens array containing oleic acid as a capping ligand manufactured by a conventional printing method, and a microscope image (right two images) of a uniform quantum dot microlens array manufactured after treatment with a capping organic material according to an embodiment of the present invention.

[0115] The inventors of the present invention have confirmed that when microlenses are manufactured using the embodiments proposed in this invention, the nozzles do not become clogged even after more than two weeks of printing, even when the lenses are printed using the same method. Furthermore, compared to conventional capping ligand materials, they have confirmed that not only is size controllable, but also that the lenses exhibit superior color transition characteristics.

[0116] FIG. 10 is a graph showing the experimental results of luminescence characteristics of a uniform quantum dot microlens manufactured after treatment with a capping organic material according to one embodiment of the present invention.

[0117] Figure 11 is a graph showing the atomic bonding of a capping organic material included in a uniform quantum dot microlens material manufactured after treatment with the capping organic material according to one embodiment of the present invention. It can be confirmed that C=O and SH bonds are included.

[0118]

[0119] According to one embodiment, the micro lens may have a hemispherical cross-section and guide the light path so that light that has left the light-emitting area is not diffused.

[0120] According to one embodiment, the quantum dot may include a core-shell structure or an alloy structure, and the quantum dot may include at least one selected from the group consisting of InP / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, CdSe / CdSx(Zn1-yCdy)S / ZnS, CdSe / CdS / ZnCdS / ZnS, InP / ZnS, InP / Ga / ZnS, InP / ZnSe / ZnS, PbSe / PbS, CdSe / CdS, CdSe / CdS / ZnS, CdTe / CdS, CdTe / ZnS, CuInS2 / ZnS, and Cu2SnS3 / ZnS.

[0121] According to one embodiment, the curable polymer may have transparent properties before curing and black matrix properties after curing.

[0122] In one embodiment, the micro lens may be manufactured by a printing method.

[0123] In one embodiment, the microlenses may have a pitch length of 10 μm to 100 μm.

[0124]

[0125] FIG. 12 is a graph comparing and analyzing the red and green luminescence characteristics of a non-uniform quantum dot microlens containing oleic acid as a capping ligand manufactured by a printing method using a conventional method and a uniform quantum dot microlens manufactured after treatment with a capping organic material according to an embodiment of the present invention.

[0126] FIG. 13 is a microscope image confirming the luminescence characteristics of a uniform quantum dot microlens array manufactured after treatment with a capping organic material according to one embodiment of the present invention.

[0127] FIGS. 14 and 15 are microscope images confirming the red and green luminescence characteristics of a uniform quantum dot microlens array manufactured after treatment with a capping organic material according to one embodiment of the present invention.

[0128] Figure 16 is an image showing a uniform quantum dot microlens array manufactured through a printing method of ink after treatment with a capping organic material according to one embodiment of the present invention, in which a homogeneous lens is formed while varying the quantum dot concentration in the ink, thereby exhibiting consistent luminescence characteristics. It can be confirmed that a homogeneous lens is formed and exhibits consistent luminescence characteristics even when the concentration is increased from 50 mg / ml to 150 mg / ml.

[0129]

[0130] Hereinafter, with reference to FIGS. 12 to 16, a micro lens array sheet using a quantum dot complex proposed in another embodiment of the present invention and its application will be described in detail.

[0131] According to another embodiment of the present invention, a microlens array sheet using a quantum dot complex includes: a base sheet; a barrier structure formed on the base sheet and defining a space in which microlenses are to be positioned; and a plurality of quantum dot microlenses formed in a space between side walls of the barrier structure, wherein the quantum dot microlenses may include one or more microlenses using the quantum dot complex according to an embodiment of the present invention.

[0132] In one embodiment, the barrier structure may be formed using a printing method.

[0133] In one embodiment, the barrier structure may be in the form of a black matrix that absorbs light.

[0134] In one embodiment, the cross-sectional height of the micro lens may be higher than the height of the barrier structure.

[0135] In one embodiment, the micro lenses may be formed in multiples and may include a quantum dot material that emits a different wavelength from the color conversion lens in an adjacent area.

[0136] According to one embodiment, the micro lens array sheet may include at least one lens that guides only the light path using an ultraviolet-curable polymer that does not include quantum dots among a plurality of micro lenses.

[0137]

[0138] Hereinafter, a method for manufacturing a micro lens array sheet using a quantum dot complex, which is another embodiment of the present invention, will be described in detail with reference to FIGS. 2 and 6 described above.

[0139] According to another embodiment of the present invention, a method for manufacturing a microlens array sheet using a quantum dot complex includes the steps of: preparing a substrate having a base sheet formed thereon; printing a barrier structure on the base sheet to define a space where a plurality of microlenses are to be formed; preparing a quantum dot microlens material to which a capping organic material is bound by replacing a capping ligand bound to a curable polymer having a quantum dot material dispersed therein with an organic material including a thiol group; forming one or more microlenses in an empty space between barrier structures on the base sheet using the microlens material; curing the curable polymer by applying light to the microlenses; and separating and removing the substrate from the base sheet.

[0140] According to one embodiment, in the step of preparing the quantum dot microlens material, the organic material including the thiol group is C3~C 20 It may be composed of a carbon chain, has a thiol group at the terminal, and includes an ester group located in the middle of the carbon chain.

[0141] According to one embodiment, the organic material including a thiol group in the step of preparing the quantum dot microlens material may include a material of the following [chemical formula 2].

[0142] [Chemical Formula 2]

[0143]

[0144]

[0145] According to one embodiment, the step of printing the barrier structure may be a dispensing process or an electrohydrodynamic printing process, and the step of forming the micro lens may be a step of printing the micro lens using an EHD printing process.

[0146]

[0147] Hereinafter, with reference to the images illustrated in FIGS. 17 to 24, the possibility of expansion into a light-emitting display array including the above-described micro lens array sheet will be described in detail.

[0148] FIG. 17 shows various graphic or character images produced using a uniform quantum dot microlens array manufactured after treatment with a capping organic material according to one embodiment of the present invention.

[0149] FIG. 18 is a graph showing the luminescence characteristics measured when a homogeneous lens is formed by varying the quantum dot concentration in the ink in a uniform quantum dot microlens array manufactured through a printing method of ink after treatment with a capping organic material according to one embodiment of the present invention.

[0150] FIG. 19 is a graph showing the measurement of luminescence characteristics of micro lenses manufactured by varying the quantum dot concentration in ink after treatment with a capping organic material according to one embodiment of the present invention, applied to a pure blue wavelength.

[0151] FIG. 20 is an image showing the luminescence characteristics of a uniform quantum dot microlens manufactured through a printing method using ink formed at a high concentration of 150 mg / ml after treatment with a capping organic material according to one embodiment of the present invention.

[0152] FIGS. 21 to 23 are microscope images showing the luminescence characteristics of a color conversion lens including quantum dots formed between the grids of a barrier formed by EHD printing a PDMS material according to an embodiment of the present invention. FIG. 21 clearly illustrates the steps of each process, and FIG. 22 confirms that even when a lens having a pitch size of 80 μm is implemented, uniform luminescence characteristics are exhibited, and FIG. 23 clearly reveals the height of the barrier and the shape of the micro lens formed between the grids according to an embodiment of the present invention, as well as its luminescence characteristics.

[0153] FIG. 24 is an image showing a color change as light is emitted from an array by applying heat to an electrode on which light-emitting elements are arranged using a micro lens according to one embodiment of the present invention.

[0154]

[0155] According to another embodiment of the present invention, a light-emitting display array including a micro-lens array sheet using a quantum dot complex comprises: a display array emitting light of a single wavelength; one or more micro-lens array sheets positioned on the display array, wherein the micro-lens array sheets include: a substrate; a barrier structure including a curable polymer on the substrate; and one or more micro-lenses using a quantum dot complex according to an embodiment of the present invention formed in a space between side walls of the barrier structure.

[0156]

[0157] The above description is merely an illustrative example of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. A cured polymer having quantum dot material dispersed therein; and A capping organic material comprising a thioether functional group that forms a bond around the cured polymer; Microlenses using quantum dot complexes.

2. In paragraph 1, The above capping material is C3~C 20 It is composed of a carbon chain, The above thioether functional group is located at the end of the carbon chain, Microlenses using quantum dot complexes.

3. In paragraph 2, The above capping material is Containing an ester group located in the middle of the above carbon chain, Microlenses using quantum dot complexes.

4. In paragraph 1, The above capping material is a thioether group of the following [chemical formula 1] bonded to the cured polymer of the quantum dot material. Microlenses using quantum dot complexes. [Chemical Formula 1] 5. In paragraph 1, The above micro lens has a hemispherical cross-section shape and guides the light path so that light that has left the light-emitting area is not diffused. Microlenses using quantum dot complexes.

6. In paragraph 1, The above quantum dot includes a core-shell structure or an alloy structure, The quantum dot comprises at least one selected from the group consisting of InP / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, CdSe / CdSx(Zn1-yCdy)S / ZnS, CdSe / CdS / ZnCdS / ZnS, InP / ZnS, InP / Ga / ZnS, InP / ZnSe / ZnS, PbSe / PbS, CdSe / CdS, CdSe / CdS / ZnS, CdTe / CdS, CdTe / ZnS, CuInS2 / ZnS and Cu2SnS3 / ZnS. Microlenses using quantum dot complexes.

7. In paragraph 1, The above curable polymer It has transparent properties before curing and black matrix properties after curing. Microlenses using quantum dot complexes.

8. In paragraph 1, The above micro lens is manufactured by printing method. Microlenses using quantum dot complexes.

9. In paragraph 1, The above micro lens has a pitch length of 10 ㎛ to 100 ㎛, Microlenses using quantum dot complexes.

10. Base sheet; A barrier structure formed on the base sheet and defining a space where a micro lens is to be positioned; and It includes a plurality of quantum dot micro lenses formed in the space between the side walls of the above barrier structure, The above quantum dot microlens comprises at least one microlens using the quantum dot complex of any one of claims 1 to 9. Microlens array sheet using quantum dot complex.

11. In paragraph 10, The above barrier structure is formed using a printing method. Microlens array sheet using quantum dot complex.

12. In paragraph 10, The above barrier structure is in the form of a black matrix that absorbs light. Microlens array sheet using quantum dot complex.

13. In paragraph 10, The cross-sectional height of the above micro lens is higher than the height of the above barrier structure, Microlens array sheet using quantum dot complex.

14. In paragraph 10, The above micro lenses are formed in multiples and include a color conversion lens in an adjacent area and a quantum dot material that emits different wavelengths. Microlens array sheet using quantum dot complex.

15. In paragraph 10, The above micro lens array sheet, A lens comprising at least one lens that guides only the light path using an ultraviolet-curable polymer that does not include quantum dots among a plurality of micro lenses; Microlens array sheet using quantum dot complex.

16. Step of preparing a substrate with a base sheet formed on top; A step of printing a barrier structure that defines a space in which a plurality of micro lenses are to be formed on the base sheet; A step of preparing a quantum dot microlens material to which a capping organic material is bound by replacing a capping ligand bound to a curable polymer in which a quantum dot material is dispersed with an organic material containing a thiol group; A step of forming one or more micro lenses using the micro lens material in the empty space between the barrier structures on the base sheet; A step of curing the curable polymer by applying light to the micro lens; and A step of separating and removing the substrate from the base sheet; comprising; A method for manufacturing a micro lens array sheet using a quantum dot complex.

17. In paragraph 16, In the step of preparing the above quantum dot micro lens material, The organic substance containing the above thiol group is C3~C 20 It is composed of a carbon chain, has a thiol group at the terminal, and includes an ester group located in the middle of the carbon chain. A method for manufacturing a micro lens array sheet using a quantum dot complex.

18. In paragraph 16, In the step of preparing the above quantum dot micro lens material, The organic material containing the above thiol group includes a material of the following [chemical formula 2]: A method for manufacturing a micro lens array sheet using a quantum dot complex. [Chemical Formula 2] 19. In paragraph 16, The step of printing the above barrier structure is: It uses a dispensing process or an electrohydrodynamic printing process, The step of forming the above micro lens is: The above micro lens is printed using an EHD printing process. A method for manufacturing a micro lens array sheet using a quantum dot complex.

20. A display array that emits light of a single wavelength; comprising at least one micro lens array sheet positioned on the display array; The above micro lens array sheet, substrate; A barrier structure comprising a curable polymer on the substrate; and A micro lens comprising at least one quantum dot complex of any one of claims 1 to 9, formed in a space between the side walls of the barrier structure; A light-emitting display array comprising a micro-lens array sheet using a quantum dot complex.

Images