KR102877867B1 - Color-convertible microlens array and manufaturing method thereof - Google Patents

Abstract

The present invention relates to an ultra-high-resolution color conversion lens array sheet using quantum dots for implementing an ultra-high-resolution RGB display and a method for manufacturing the same. In one embodiment of the present invention, a color conversion micro lens array sheet first forms a barrier structure to determine the diameter of a lens and the distance between adjacent lenses, and a structure in the form of a color conversion lens including quantum dots fills the empty space between the barriers.

Description

Color-converting microlens array sheet and manufacturing method thereof {COLOR-CONVERTIBLE MICROLENS ARRAY AND MANUFATURING METHOD THEREOF}

The present invention relates to a color conversion micro lens array sheet and a method for manufacturing the same, and more particularly, to a color conversion 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.

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

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.

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.

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.

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.

In addition, when printing quantum dot ink, it is possible to achieve simplification of equipment configuration compared to conventional lithography methods, but there is a problem in 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.

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

In order to achieve the above purpose, a color conversion 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 structure in the form of a color conversion lens containing quantum dots.

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

A color conversion lens array sheet according to one embodiment of the present invention comprises: a base sheet; a barrier structure formed on the base sheet and defining a space in which a color conversion lens is to be positioned; and at least one color conversion lens formed in a space between side walls of the barrier structure and including a cured polymer in which a quantum dot material is dispersed.

According to one embodiment, the color conversion lens may have a hemispherical cross-section shape and guide the light path so that light outside the light-emitting area is not diffused.

In one embodiment, the color conversion lens may include a micro-sized lens.

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.

In one embodiment, the curable polymer may have transparent properties before curing and black matrix properties after curing.

In one embodiment, both the barrier structure and the color conversion lens may be formed by printing.

In one embodiment, the barrier structure may include a lattice shape.

In one embodiment, the cross-sectional height of the color conversion lens may be higher than the height of the barrier structure, and the width of the barrier structure may be several micrometers to several hundred micrometers.

In one embodiment, the color conversion lenses may be formed in multiples and may include a quantum dot material that emits a different wavelength from the color conversion lenses in adjacent areas.

According to another embodiment of the present invention, a method for manufacturing a color conversion lens array sheet includes the steps of: preparing a substrate having a base sheet formed thereon; printing a barrier structure defining a space in which a plurality of color conversion lenses are to be formed on the base sheet; forming one or more color conversion lenses using a curable polymer having a quantum dot material dispersed in the empty space between the barrier structures on the base sheet; curing the curable polymer by applying light to the color conversion lenses; and peeling and removing the substrate from the base sheet.

According to one embodiment, the barrier structure may be formed by laminating a photocurable polymer through repeated printing to increase the height separating the space where each lens is to be positioned, and then curing the barrier structure by irradiating it with ultraviolet rays after laminating the polymer.

In one embodiment, the barrier structure may be transparent when printing is performed and then become a black matrix that absorbs light after curing.

According to one embodiment, the step of printing the barrier structure may be performed using a dispensing process or an electrohydrodynamic printing process.

According to one embodiment, the step of forming the color conversion lens may be printing the color conversion lens using an EHD printing process.

According to one embodiment, the curable polymer in which the quantum dot material forming the color conversion lens is dispersed may be formed by mixing 2.00 parts by weight to 10.50 parts by weight of each of a quantum dot solution emitting green light and red light, relative to 100 parts by weight of the curable polymer.

According to one embodiment, the quantum dot solution is a quantum dot material dispersed in a volatile organic solvent, and the curable polymer in which the quantum dot material is dispersed may be transparent.

According to another embodiment of the present invention, a light-emitting display array including a color conversion lens array sheet comprises: a display array emitting light of a single wavelength; at least one color conversion lens array sheet positioned on the display array, wherein the color conversion lens array sheet comprises: a substrate; a barrier structure including a curable polymer on the substrate; and a plurality of color conversion lenses including a cured polymer formed in a space between side walls of the barrier structure.

According to one embodiment, the color conversion lens array sheet may be a color conversion lens array sheet according to one embodiment of the present invention.

According to one embodiment, the color conversion lens array sheet may include at least one lens that performs color conversion using an ultraviolet-curable polymer having quantum dots dispersed therein, and at least one lens that only guides a light path using an ultraviolet-curable polymer that does not include quantum dots.

A color conversion 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 producing a full-color display to implement three RGB colors, thereby achieving simplification of the process method compared to a method of producing and driving LEDs of three different colors.

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.

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.

In addition, since the color-shifting 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-shifting effect.

FIG. 1 is an exemplary drawing for explaining a method for manufacturing a color conversion microlens according to one embodiment of the present invention.
Figure 2 is an actual image of the lens formation process through the EHD printing process on a barrier structure.
Figure 3 is an example of a color conversion lens array sheet manufactured using a printing process.
Figure 4 is an actual image showing the fluorescence characteristics of green and red color conversion lens array structures of various diameters.
Figure 5 is an actual image showing a 7 x 7 full color color conversion sheet and the fluorescence characteristics of the sheet.

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.

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 forming process through an EHD printing process on a barrier structure.

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.

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.

In the case of barrier structure materials, as described below, by utilizing ultraviolet-curable materials, such as polymer materials that constitute the mixture of materials for color conversion lenses, the effect of height reduction due to solvent evaporation after curing can be eliminated, and patterning can be performed to the desired size. In addition, by utilizing materials that are transparent during printing but change color upon curing, and whose color absorbs light after ultraviolet curing, the production of a barrier in the form of a black matrix can be achieved.

Next, a color-conversion lens is printed in the empty space 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.

At this time, in order 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 color conversion lens 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.

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 specific 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.

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.

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.

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.

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.

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.

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.

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

When manufacturing color-shifting lenses, 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 position of a previously fabricated barrier structure.

A display array that emits short-wavelength light is positioned at the bottom of the color conversion lens array sheet, and after positioning blue light, which has the shortest wavelength, red light is emitted using a lens containing quantum dots that cause a color conversion to red light, and green light is emitted using a quantum dot lens that causes a color conversion 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.

Next, the color conversion lens array sheet is removed from the fixed substrate and attached to the desired location. The color conversion lens 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 color conversion lens array sheet manufactured later can be attached to the desired location and utilized in the form of a color filter. For example, in the case of a color conversion lens array sheet manufactured on a plastic substrate, it is removed from the fixed substrate and attached to the desired location.

Figure 3 is an example of a color conversion lens array sheet manufactured using a printing process.

Referring to Fig. 3, a barrier structure is first formed to determine the diameter of the color conversion lens and the distance between adjacent lenses, and then a color conversion lens 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 color conversion lens containing quantum dots. Through this configuration, the diameter of the color conversion lens and the distance between the color conversion layers can be determined.

According to one embodiment of the present invention, a color conversion 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 color conversion 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 for 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.

According to an embodiment of the present invention, since the color conversion lens is formed in a hemispherical shape, the light path is changed by being refracted on the surface of the color conversion lens. When the upper area vertically overlapping with each color conversion lens is defined as the light-emitting area of the color conversion lens, the light emitted from the color conversion lens can be refracted on the lens surface so as to be focused on the light-emitting area. In other words, the hemispherical color conversion lens 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 color conversion lens can prevent color mixing between neighboring pixels.

Figure 4 is an actual image showing the fluorescence characteristics of green and red color conversion lens array structures of various diameters.

As illustrated in Fig. 4, by controlling the voltage and/or pressure conditions of the electrohydrodynamic printing (EHD) method, it is possible to easily implement micro lenses with various diameters. In addition, the color conversion lens array sheet according to one embodiment of the present invention can form a closer distance between adjacent color conversion lenses than in the conventional method through a barrier structure.

Figure 5 is an actual image showing a 7 x 7 full color color conversion sheet and the fluorescence characteristics of the sheet.

As illustrated in Fig. 5, a color conversion lens that emits red light and a color conversion lens that emits green light are alternately arranged on a color conversion lens array sheet, and it can be confirmed that red light and green light are alternately converted through the color conversion lens array sheet.

Meanwhile, although FIG. 5 is not illustrated to explain the color conversion of blue light into red light and green light, the color conversion lens array sheet according to one embodiment of the present invention may include a lens for setting an optical path.

The optical path setting lens is formed on a color conversion lens array sheet corresponding to an area where blue light is emitted. Here, the optical path setting microlens 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 optical path setting microlens. Since the optical path setting lens does not contain quantum dots, color conversion does not occur for blue light. Instead, the blue light can be concentrated on an emission area corresponding to an upper area that vertically overlaps with the optical path setting lens, and the blue light can be prevented from invading the emission areas of other lenses.

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 (19)

base sheet;
A barrier structure formed on the base sheet and defining a space where a color conversion lens is to be positioned; and
A color conversion lens comprising a cured polymer having a quantum dot material dispersed therein, formed in a space between the side walls of the barrier structure; comprising at least one;
The cross-sectional shape of the above barrier structure is semicircular,
The polymer forming the above barrier structure has transparent properties before curing and black matrix properties after curing.
Color conversion lens array sheet.
In the first paragraph,
The above color conversion lens has a hemispherical cross-section shape and guides the light path so that light beyond the light-emitting area is not diffused.
Color conversion lens array sheet.
In the first paragraph,
The above color conversion lens includes a micro-sized lens.
Color conversion lens array sheet.
In the first paragraph,
The above quantum dot material includes a core-shell structure or an alloy structure,
The above quantum dot material 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.
Color conversion lens array sheet.
delete In the first paragraph,
The above barrier structure and the color conversion lens are both formed by printing.
Color conversion lens array sheet.
In the first paragraph,
The above barrier structure includes a lattice shape,
Color conversion lens array sheet.
In the first paragraph,
The cross-sectional height of the above color conversion lens is higher than the height of the above barrier structure,
The width of the above barrier structure is from several micrometers to several hundred micrometers,
Color conversion lens array sheet.
In the first paragraph,
The above color conversion lenses are formed in multiples and include a quantum dot material that emits a different wavelength from the color conversion lenses of adjacent areas.
Color conversion lens array sheet.
A step of preparing a substrate having a base sheet formed on top;
A step of printing a barrier structure that defines a space in which a plurality of color conversion lenses are to be formed on the base sheet;
A step of forming one or more color conversion lenses using a curable polymer in which a quantum dot material is dispersed in a void space between barrier structures on the base sheet;
A step of curing the curable polymer by applying light to the color conversion lens; and
A step of removing the substrate by peeling it from the base sheet;
Manufacturing a color conversion lens array sheet of the first clause,
A method for manufacturing a color conversion lens array sheet.
In Article 10,
The above barrier structure is,
The photo-curable polymer is laminated and formed to increase the height separating the space where each lens will be located through repeated printing.
After the laminate formation is carried out, it is cured by irradiating with ultraviolet rays.
A method for manufacturing a color conversion lens array sheet.
In Article 11,
The above barrier structure is transparent when printing is performed, and becomes a black matrix that absorbs light after curing.
A method for manufacturing a color conversion lens array sheet.
In Article 10,
The step of printing the above barrier structure is:
Using a dispensing process or an electrohydrodynamic printing process,
A method for manufacturing a color conversion lens array sheet.
In Article 10,
The step of forming the above color conversion lens is:
The color conversion lens is printed using the EHD printing process.
A method for manufacturing a color conversion lens array sheet.
In Article 10,
The curable polymer in which the quantum dot material forming the above color conversion lens is dispersed is
It is formed by mixing 2.00 to 10.50 parts by weight of each of a quantum dot solution emitting green light and red light with respect to 100 parts by weight of a curable polymer.
A method for manufacturing a color conversion lens array sheet.
In Article 15,
The above quantum dot solution is a quantum dot material dispersed in a volatile organic solvent,
The curable polymer in which the quantum dot material is dispersed is transparent.
A method for manufacturing a color conversion lens array sheet.
A display array that emits light of a single wavelength;
Comprising at least one color conversion lens array sheet of the first claim positioned on the display array,
The above color conversion lens array sheet,
substrate;
A barrier structure comprising a curable polymer on the substrate; and
A color conversion lens comprising a cured polymer formed in a space between side walls of the barrier structure; comprising a plurality of
A light-emitting display array comprising a color-shifting lens array sheet.
delete In Article 17,
The above color conversion lens array sheet,
A lens that performs color transition using a UV-curable polymer in which quantum dots are dispersed; and
Each lens comprising at least one lens that guides only the light path using an ultraviolet-curable polymer that does not include quantum dots;
A light-emitting display array comprising a color-shifting lens array sheet.