KR102267595B1 - Optical sheet with the improved brightness and color uniformity - Google Patents

Abstract

The present invention relates to an optical sheet having improved luminance and color uniformity, wherein the optical sheet of the present invention further includes one or more spacers in a polymer resin layer formed by dispersing a light emitting body in a polymer resin, thereby improving the thickness uniformity of the polymer resin layer Accordingly, the luminance and color uniformity of the optical sheet including the polymer resin layer are also improved.

Description

Optical sheet with the improved brightness and color uniformity

The present invention relates to an optical sheet having improved luminance and color uniformity.

Quantum dots are semiconductor materials with a crystal structure of several nanometers, and have different wavelengths depending on their size. By using these quantum dots as a fluorescent material or a light emitting material, it is possible to improve the characteristics of a display. Or it is known that it can be used as a display itself. On the other hand, the quantum dots are used, for example, combined in a small amount in a polymer optical sheet that enters the backlight unit (BLU).

However, the light emitting material such as quantum dots has an oxidation problem due to surface oxidation when exposed to water and oxygen in the air. As a way to compensate for this, a polymer resin in which the light emitting material is dispersed is dispersed between two barrier films and then cured to make the optical sheet This optical sheet is arranged (on-surface method) on the light guide plate of the blue BLU module. On the other hand, the optical sheet can respond to various display screen sizes from small to large.

On the other hand, the optical sheet is manufactured in a structure attached by simple lamination or an adhesive, or is manufactured in a laminate method in which a pair of sheets is passed through a roller and bonded through pressure. However, in the case of the lamination method in which a roller is passed and joined, there is a problem in that the sheet to which the pressure is applied is bent because it is pressed in one sheet direction among a pair of sheets. Accordingly, in the conventional lamination method, it is difficult to match the thickness uniformity, so that the luminance of the optical sheet is lowered or the color uniformity is lowered.

Republic of Korea Patent Publication No. 2010-0029519 (2010.03.17)

Therefore, in order to solve the problems of the prior art as described above, the present invention is to provide an optical sheet with improved luminance and color uniformity by additionally providing a spacer in the polymer resin layer including the light emitting body formed between the two barrier films. .

A first barrier film in one embodiment of the present invention; a polymer resin layer formed on the first barrier film and in which a light emitting body is dispersed; and a second barrier film formed on the polymer resin layer, wherein the polymer resin layer of the optical sheet provides an optical sheet including one or more spacers.

In another embodiment of the present invention, (a) preparing a first barrier film; (b) disposing a second barrier film spaced apart from the first barrier film to face the first barrier film; And (c) passing between the laminator rolls while applying the polymer resin crude liquid in which the light emitting body and the spacer are dispersed between the first barrier film and the second barrier film to prepare an optical sheet; to provide.

In another embodiment of the present invention, (a) dispersing one or more spacers on the first barrier film; (b) disposing a second barrier film spaced apart from the first barrier film to face the first barrier film; And (c) passing between the laminator rolls while applying the polymer resin crude liquid in which the light emitting material is dispersed between the first barrier film and the second barrier film to prepare an optical sheet; provides an optical sheet manufacturing method comprising a .

The optical sheet of the present invention secures the thickness uniformity of the polymer resin layer by additionally providing a spacer in addition to the light emitting body in the polymer resin layer formed between the two barrier films, thereby improving the luminance and color uniformity of the optical sheet.

On the other hand, in the optical sheet of the present invention, the light emitting body included in the polymer resin layer is a non-cadmium-based quantum dot, and is more environmentally friendly than an optical sheet containing a cadmium-based quantum dot.

1A is an optical sheet manufactured according to an embodiment of the present invention.
Figure 1b is an optical sheet manufactured according to another embodiment of the present invention.
1C is an optical sheet manufactured according to another embodiment of the present invention.
2A is an optical sheet manufactured according to another embodiment of the present invention.
Figure 2b is an optical sheet manufactured according to another embodiment of the present invention.
3 is an optical sheet manufactured according to another embodiment of the present invention.
4 is a schematic diagram showing a method of manufacturing an optical sheet using a roll-to-roll process according to another embodiment of the present invention.
5 is a schematic view showing two barrier films and a polymer resin layer introduced between a pair of rollers in a roll-to-roll process according to another embodiment of the present invention.
6 is a schematic diagram illustrating a process of dispersing a spacer on a barrier film by a spray method according to another embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

optical sheet

An optical sheet according to an embodiment of the present invention includes a first barrier film; a polymer resin layer formed on the first barrier film and in which a light emitting body is dispersed; and a second barrier film formed on the polymer resin layer, wherein the polymer resin layer of the optical sheet includes one or more spacers.

More specifically, the optical sheet according to an embodiment of the present invention is disposed in contact with a polymer resin layer including one or more spacers and a light emitting body, and the upper and lower surfaces of the polymer resin layer, respectively, to protect the polymer resin layer from external conditions. It consists of two barrier films to protect from

In one embodiment of the present invention, the spacer is formed inside the polymer resin layer spaced apart from the first barrier film and the second barrier film or is in contact with the first barrier film and is formed at the bottom of the polymer resin layer, It can be used for the purpose of improving the thickness uniformity of the resin layer, and when the polymer resin layer has a high thickness uniformity, the luminance of the optical sheet is improved and excellent color uniformity can be secured. On the other hand, the spacer may have a particle form, for example, may be in the form of beads (beads).

More specifically, in the optical sheet, securing high brightness and excellent color uniformity depends on whether the thickness of the polymer resin layer formed between the first and second barrier films is maintained at regular intervals. This is because the light emission of quantum dots, which is a light emitting body, acts as a surface light source, so the number of light emitting materials increases in the portion where the thickness of the polymer resin layer is relatively thick, and the luminance increases, and in the portion with a relatively thin thickness, the number of light emitting materials decreases, so that the luminance decreases. Because. As a result, when the thickness of the polymer resin layer is not constant, the transmittance of light passing through the portion may be different, so there may be a problem of spatially non-uniform brightness.

In an embodiment of the present invention, the spacer included in the polymer resin layer may be a transparent material. Here, the transparent material means a material having a transmittance of visible light equal to or greater than a predetermined threshold, and for example, a material having transmittance of visible light of 90% or greater.

In one embodiment of the present invention, the spacer may include one or more materials selected from the group consisting of an acrylic resin, an epoxy resin, and a urethane resin, or a combination thereof. In particular, when the spacer includes an acrylic resin, it is advantageous because of its high compatibility and the effect of crude liquid processability and dispersibility. Also, in an embodiment of the present invention, the spacer may further include quantum dots.

Meanwhile, in one embodiment of the present invention, the total area of the spacer included in the polymer resin layer may have a range of 25 to 40% of the total area of the polymer resin layer. Since the spacer is included in the area range within the polymer resin layer, it is possible to not only secure thickness uniformity, which was difficult to secure in the conventional lamination method, but also obtain sufficient luminous efficiency.

Meanwhile, according to an embodiment of the present invention, the thickness of the spacer included in the polymer resin layer may be in the range of 70 to 100% of the thickness of the polymer resin layer. When the thickness of the spacer is less than 70% of the thickness of the polymer resin layer, it may be difficult to secure the thickness uniformity of the polymer resin layer, and when it exceeds 100% of the thickness of the polymer resin layer, it is difficult to match the desired thickness of the optical sheet This can be.

Meanwhile, there may be one or more spacers included in the polymer resin layer, and may be spaced apart from each other at intervals of 50 to 300 μm. If the spacing between the spacers is less than 50 μm, as the area of the void area becomes small and the dispersion degree of the light emitting body falls, there may be problems in the thickness non-uniformity of the polymer resin layer, and thus the luminance non-uniformity and color non-uniformity of the optical sheet. , when the spacing between the spacers is greater than 300 μm, the spacers may collapse due to subsidence of the barrier film, and it may be difficult to achieve uniformity in thickness of the polymer resin layer.

On the other hand, the cross-section of the spacer included in the polymer resin layer may have one or more types selected from the group consisting of polygons and circles, and when the cross-section of the spacer is polygonal, the cross-section of the spacer is a trapezoid, a quadrangle, a triangle, a pentagon, etc. It may be selected from among shapes, and when the cross-section of the spacer is circular, the cross-section may be selected from shapes such as circular, oval, and semi-circular shapes.

Meanwhile, the spacer in the polymer resin layer may be formed adjacent to or spaced apart from the barrier film, and may be formed in various shapes.

In one embodiment of the present invention, the cross section of the spacer included in the polymer resin layer is circular, the spacer is spaced apart from the first barrier film and the second barrier film, and has a regular or irregular island shape inside the polymer resin layer may be included as (see FIGS. 1A and 1C).

On the other hand, in another embodiment of the present invention, the cross section of the spacer included in the polymer resin layer is rectangular, the spacer is spaced apart from the first barrier film and the second barrier film, and is regular or irregular inside the polymer resin layer It may be included in the form of an in-island (see FIG. 1B ).

Meanwhile, in another embodiment of the present invention, the cross section of the spacer included in the polymer resin layer is circular, the spacer is in contact with the first barrier film, and has a regular or irregular island shape on the plane of the first barrier film It may be included as (see FIG. 2a).

Meanwhile, in another embodiment of the present invention, the cross section of the spacer included in the polymer resin layer is rectangular, the spacer is in contact with the first barrier film, and has a regular or irregular island shape on the plane of the first barrier film may be included as (see FIG. 2b).

Meanwhile, the polymer resin layer is formed by dispersing a light emitting body in the matrix using a polymer resin as a matrix, and may have a layer structure of one or more layers.

In one embodiment of the present invention, the polymer resin used as the matrix preferably has low oxygen and moisture permeability, and also preferably has high light stability and chemical stability. In addition, the liquid refractive index of the polymer resin may be 1.42 to 1.65, specifically 1.49 to 1.61.

In one embodiment of the present invention, the polymer resin is, for example, epoxy, acrylate, norborene, polyurethane, polyethylene, polyphenylalkylsiloxane, polydiphenylsiloxane, polydialkylsiloxane, silsesquioxanes, It may be at least one polymer resin selected from the group consisting of fluorinated silicones, and vinyl and hydride-substituted silicones.

On the other hand, in an embodiment of the present invention, the light emitting body may be a quantum dot, and the quantum dot refers to a substantially single crystalline nanostructure, which absorbs the primary light emitted from the light source and then emits the secondary light. and may emit light having a different wavelength depending on its size. On the other hand, the typical size of the quantum dot may be 1 to 10 nm, and when the size of the quantum dot is 4 to 5 nm, after absorbing the primary light from the light source, secondary light having a red color may be emitted, and 2 to 3 In the case of nm, after absorbing the primary light from the light source, the secondary light having a green color may be emitted.

On the other hand, the light emitting body may be uniformly dispersed in the matrix, and when the polymer resin layer has a multilayer structure, light emitting bodies of different sizes may be disposed in each layer, and light emitting bodies of different sizes are mixed and dispersed in a single layer. may have

Meanwhile, the light-emitting body according to an embodiment of the present invention is a non-cadmium-based quantum dot, and the quantum dots for use in the present invention may include any suitable inorganic material. In an embodiment of the present invention, the non-cadmium-based quantum dots may include an inorganic material selected from the group consisting of group II-VI, group III-V, group IV-VI, and group IV semiconductor.

In one embodiment of the present invention, the non-cadmium-based quantum dots are Si, Ge, Sn, Se, Te, B, C, P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InSe, InN, InP, InAs, InSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, ZnO, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, 1 selected from the group consisting of MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si ₃ N ₄ , Ge ₃ N ₄ and combinations thereof It may contain more than one kind of inorganic material.

On the other hand, the thickness of the polymer resin layer may be 10 to 120㎛. When the thickness of the polymer resin layer is less than 10 μm, the quantum dots must exist at a higher density than the thick resin layer in order to satisfy a certain level of color conversion properties. It is expected that the efficiency decreases due to accelerated degradation of quantum dots, or that other quantum dots that absorb the light from the primary light source and then absorb the secondary light emitted by other quantum dots continuously absorb the efficiency decrease, and if it exceeds 120㎛, high-density quantum dots Efficiency reduction caused by the process may not occur or the degree will be lowered, but the problem of lowering thickness uniformity in the coating process during commercialization, curling problems that may occur during product winding, lowering of winding amount per roll, application of large-diameter cores, etc. Economical issues such as product defects or increased production cost may be problematic.

More specifically, when the thickness of the polymer resin layer exceeds 120 μm, when a thin substrate of 120 μm or less is applied, it becomes vulnerable to wrinkles due to heat generated during curing, and a thick film substrate is required. In this case, the final product Since the thickness of the wire approaches 400 μm, it may cause problems during winding or increase the thickness of the entire device when actually applied to the BLU.

On the other hand, the first barrier film and the second barrier film in contact with one surface and the other surface of the polymer resin layer, respectively, serves to prevent the lifespan of the light emitting body in the polymer resin layer from being reduced due to penetration of moisture or oxygen. On the other hand, in the present invention, it should be understood that the first and second barrier films are arbitrarily ordered in order to distinguish them from each other.

Meanwhile, the barrier film may include a substrate and a barrier layer formed on the substrate, wherein the barrier layer is at least one layer selected from the group consisting of an organic layer, an inorganic layer, and an organic/inorganic composite layer in which an organic material and an inorganic material are combined. may include, and the barrier layer may have a single-layer or multi-layer structure.

The substrate is polyethylene terephthalate, polyethylene naphthalate, acrylic resin, polycarbonate, polystyrene, polyolefin, cellulose acetate, and waterproof It may be at least one selected from the group consisting of vinyl chloride (weather-resistant vinyl chloride), for example, may be polyethylene terephthalate.

On the other hand, in one embodiment of the present invention, when the barrier layer is an organic layer, the organic material included in the organic layer is silsesquioxane, siloxane, isobornyl acrylate, alkoxy silanes, polydimethylsiloxane, vinylmethoxysiloxane, Polyphenylmethylsilsesquinoxane, polyphenylalkylsiloxane, polydialkylsiloxane, fluorinated silicones and hydride substituted silicones, urethane acrylates, epoxy acrylates styrene, acrylates, norborene, polyethylene and styrene-butyl -It may be at least one selected from the group consisting of styrene polymer, for example, may be a random type of silsesquioxane.

On the other hand, in an embodiment of the present invention, when the barrier layer is an inorganic layer, the inorganic material included in the inorganic layer is Si, Al, In, Sn, Zn, Zr, Ti, Cu, Ce, Yt, La, Ba, Mg, F ₂ , Sb, Sr and Ta may include an oxide, nitride, carbide, oxynitride, oxycarbide, nitride carbide, or oxynitride carbide containing at least one metal selected from the group consisting of, for example, For example, it _{may be SiO x} 1 layer.

Meanwhile, in one embodiment of the present invention, the thickness of the barrier layer may be 0.1 to 2㎛. When the thickness of the barrier layer is less than 0.1 μm, there may be a problem that non-curing occurs due to surface oxidation, and when the thickness of the barrier layer is more than 2 μm, cracks occur on the surface during the roll-to-roll process, resulting in poor performance there may be

Meanwhile, in one embodiment of the present invention, the optical sheet may further include a barrier material coating layer 400 formed on both sides of the first barrier film and the polymer resin layer. The barrier material coating layer may be made of substantially the same material as the components of the organic or inorganic layer of the barrier film described above, and is not particularly limited as long as it is a material that prevents penetration of moisture and oxygen in the thickness direction of the polymer resin layer. (See Fig. 3).

Optical sheet manufacturing method

Various methods may be used to manufacture the optical sheet according to the present invention, and for example, a spray method, a screen printing method, an imprinting method, or a direct/indirect pattern method may be used to form a spacer.

In the case of the spray method, spherical particles having a CV of 10% or less of a certain size are dispersed in a solvent and then the particles are uniformly dispersed by high pressure. At this time, it is necessary to control the spray type, pressure, distance, amount of solvent, content of particles, dispersing power, etc.

On the other hand, in the case of the screen printing method, the shape of one or more spacers is a sphere, a square, a trapezoid, a triangle, etc., and a mold is made, a polymer resin is applied on the mold, and then cured. Thereafter, a spacer is formed through a process of removing the mold.

On the other hand, in the case of the imprinting method, a mold having the shape of one or more spacers is made, a polymer resin is applied on the barrier film, the mold is stamped, and then the mold is cured.

On the other hand, in the case of the direct/indirect pattern method, a roll having one or more spacer shapes is manufactured, and a spacer shape is formed by a polymer resin while the barrier film passes through the roll. The direct/indirect pattern method is to use the barrier film with the pattern produced in this way as a mold.

On the other hand, the method of forming the polymer resin layer between the two barrier films when manufacturing the optical sheet according to the present invention is not particularly limited, for example, a roll-to-roll method may be used.

An optical sheet manufacturing method according to an embodiment of the present invention comprises the steps of (a) preparing a first barrier film; (b) disposing a second barrier film spaced apart from the first barrier film to face the first barrier film; And (c) passing between the laminator rolls while applying the polymer resin crude liquid in which the light emitting body and the spacer are dispersed between the first barrier film and the second barrier film to prepare an optical sheet; may include.

In particular, in the present invention, the optical sheet manufacturing may be performed by a roll-to-roll process that passes between the laminator rolls, and the roll-to-roll process may be performed using a roll-to-roll apparatus according to an embodiment of the present invention. . A roll-to-roll device according to an embodiment of the present invention includes: a first roller 500 having a groove formed in the center of the roller; and a second roller 550 formed to be spaced apart from the first roller at a predetermined interval (see FIGS. 4 and 5). Meanwhile, in the present specification, a roller having a groove formed in the center of the pair of rollers is referred to as a first roller, and a roller having no groove formed in the center is referred to as a second roller.

Meanwhile, the first roller is divided into a center portion and an edge portion, and a groove is formed in the center portion. Meanwhile, means 600 for supplying a barrier material may be provided on both side portions of the groove formed in the center of the first roller (see FIG. 5 ). The means is a barrier material on both sides of the first barrier film and on both sides (thickness direction) of the polymer resin layer through both side portions of the groove when the first barrier film is driven along the groove of the first roller having a groove formed in the center. It is not particularly limited as long as it is configured so that it can be coated by supplying it. In particular, the barrier material supply means 600 may be configured to uniformly coat the barrier material on both sides of the first barrier film and on both sides of the polymer resin layer, for example, several on both sides of the groove, Dozens or hundreds of fine holes are formed as needed, and the barrier material may be supplied from the outside of the roller.

Meanwhile, the bottom portion of the groove formed in the center of the first roller may have a surface roughness of 50 nm or less. When the surface roughness of the bottom portion of the groove exceeds 50 nm, dimples may occur due to pressing on the product surface due to the non-uniformity of the surface, and there may be a problem in that the thickness uniformity is also reduced.

On the other hand, in an embodiment of the present invention, the material of the roller may be a material generally used in the art, but it is preferable to use stainless steel (SUS) for the first roller and the second roller can do. For example, if the roller is composed of only rubber material or the material of one roller is used as rubber, it may be difficult to secure uniform thickness due to the elasticity of the roller material.

On the other hand, the optical sheet manufacturing method according to another embodiment of the present invention comprises the steps of (a) dispersing one or more spacers on a first barrier film; (b) disposing a second barrier film spaced apart from the first barrier film to face the first barrier film; And (c) passing between the laminator rolls while applying the polymer resin crude liquid in which the light emitting material is dispersed between the first barrier film and the second barrier film to prepare an optical sheet; may include.

For example, in the above process, one or more spacers are first dispersed on the first barrier film (step a). The process of dispersing and disposing the spacers is not particularly limited, but may be formed by, for example, a spray method using a spray device 700 (see FIG. 6 ). Hereinafter, the roll-to-roll process is the same as the method described above.

As described above, the optical sheet of the present invention includes a light emitting body and one or more spacers in the polymer resin layer formed between the two barrier films, thereby improving the thickness uniformity of the polymer resin layer, and luminance and color of the optical sheet including the same. It also improves uniformity. On the other hand, since the optical sheet of the present invention uses a non-cadmium-based quantum dot as a light emitting body, it is more environmentally friendly than a conventional optical sheet including a cadmium-based quantum dot.

Hereinafter, the present invention will be described in more detail by way of Examples and the like, but the scope and content of the present invention may not be construed as being reduced or limited by the Examples below. In addition, based on the disclosure of the present invention including the following examples, it is clear that a person skilled in the art can easily practice the present invention for which no specific experimental results are presented, and such modifications and modifications are included in the attached patent. It goes without saying that they fall within the scope of the claims.

Example

Example 1

A spacer (PMMA, MH-50FD, Kolon Corporation) was dispersed at 3 wt% in a polymer resin (IBOA, Styrene, acylate) in which a light emitting material (non-cadmium-based quantum dots) was dispersed. The spacer was a spherical particle with a size of 50 μm, and had a circular cross section, and the total area corresponded to 30% of the total area of the polymer resin.

Next, the first barrier film (iComponent, 125㎛, PET, SiO _x ) and the second barrier film opposite the first barrier film (IComponent, 125㎛, PET, SiO _x ) were placed between the laminator rolls. The polymer resin was passed between the laminator rolls while applying by adjusting the gap of the laminator roll so that the thickness of the polymer resin was 60 μm between the first barrier film and the second barrier film. At this time, the speed was maintained at about 2.0 mpm.

Thereafter, the optical sheet was manufactured by UV curing the polymer resin layer formed between the first and second barrier films exiting the laminator roll. The exposure amount at this time was about 400 mJ/cm ² , and the UV lamp type used during UV curing was an electrodeless type D-bulb of Fusion. On the other hand, the thickness of the first and second barrier films used was 125 μm, and products having a WVTR = 10 ^-2 g/m ² /day level in terms of moisture permeability were used.

On the other hand, for thickness uniformity evaluation, 5% positions were coordinated on the length of the long side (l) and the short side (d) of the manufactured optical sheet to measure the thickness, and then the uniformity was calculated.

(For reference, the uniformity is calculated by the following formula.

Uniformity = (maximum-min)/average × 100 (%)

Meanwhile, the thickness uniformity is (MAX-MIN)/average value*100. At this time, as for the thickness uniformity, the lower the numerical value, the more uniform the thickness.)

As a result of measuring the thickness uniformity of the polymer resin layer of the optical sheet obtained in this way (Micrometer, mitutoyo, 5*5cm, center measurement), the thickness uniformity was 8%.

Example 2

An optical sheet was obtained in the same manner as in Example 1, except that the shape of the cross-section of the spacer particle was changed to an elliptical shape instead of a circular shape.

As a result of measuring the thickness uniformity of the polymer resin layer of the optical sheet obtained in this way (Micrometer, mitutoyo, 5*5cm, center measurement), the thickness uniformity was 9%.

Example 3

An optical sheet was obtained in the same manner as in Example 1, except that the shape of the cross-section of the spacer particle was changed to a square instead of a circle.

As a result of measuring the thickness uniformity of the polymer resin layer of the optical sheet obtained in this way (Micrometer, mitutoyo, 5*5cm, center measurement), the thickness uniformity was 9%.

Example 4

An optical sheet was obtained in the same manner as in Example 1, except that the spacer was formed by a spray method.

As a result of measuring the thickness uniformity of the polymer resin layer of the optical sheet obtained in this way (Micrometer, mitutoyo, 5*5cm, center measurement), the thickness uniformity was 7%.

Example 5

An optical sheet was obtained in the same manner as in Example 1, except that the spacers were formed directly on one surface of the first barrier film in a patterned manner.

As a result of measuring the thickness uniformity of the polymer resin layer of the optical sheet obtained in this way (Micrometer, mitutoyo, 5*5cm, center measurement), the thickness uniformity was 5%.

Example 6

An optical sheet was obtained in the same manner as in Example 1, except that the spacer was formed by the imprinting method.

As a result of measuring the thickness uniformity of the polymer resin layer of the optical sheet obtained in this way (Micrometer, mitutoyo, 5*5cm, center measurement), the thickness uniformity was at the level of 6%.

Comparative Example 1

The first barrier film and the second barrier film are placed between the laminator rolls, and a polymer resin (IBOA, Styrene, acylate) in which non-cadmium-based quantum dots are dispersed between the first barrier film and the second barrier film is applied to a thickness of 60 μm. It passed between the laminator rolls while applying by adjusting the gap of the laminator roll. At this time, the speed was maintained at about 2.0 mpm.

Thereafter, the optical sheet was manufactured by UV curing the polymer resin layer in which the quantum dots were dispersed, which were applied between the first and second barrier films coming out of the laminator roll. The exposure dose at this time was about 400 mJ/cm ² , and the UV lamp type used for UV curing was an electrodeless type D-bulb of Fusion. On the other hand, the thickness of the first and second barrier films used was 125 μm, and ^{products having a WVTR = 10 -2} g/m ² /day level in terms of moisture permeability were used.

As a result of measuring the thickness uniformity of the polymer resin layer of the optical sheet obtained in this way (Micrometer, mitutoyo, 5*5cm, center measurement), the thickness uniformity was at the level of 20%.

spacer size Spacer formation method Spacer cross-section Spacer area in polymer resin layer Polymer resin layer thickness thickness uniformity Example 1 50 μm dispersed in polymer resin circle 30% 60 μm 8% Example 2 50 μm dispersed in polymer resin oval 30% 60 μm 9% Example 3 50 μm dispersed in polymer resin Square 30% 60 μm 9% Example 4 50 μm spray circle 30% 60 μm 7% Example 5 50 μm direct pattern circle 30% 60 μm 5% Example 6 50 μm imprinting circle 30% 60 μm 6% Comparative Example 1 - - - 60 μm 20%

Experimental Example 1

The optical sheets prepared according to Examples 1 to 6 and Comparative Example 1 according to the present invention are laminated on the upper part of the light guide plate of the 7-inch Blue LED 1Horizontal BLU, and the brightness enhancement film is laminated on the upper part of the optical sheet, and then the BLU is mounted and fixed, The luminance at 7*5=35 points was measured using a luminance meter (model name: SR-3, Japan TOPCON).

The average value of the measured luminance and the luminance uniformity (MAX/MIN) were calculated and shown in Table 2 below. In this case, the color uniformity was calculated as the rate of change compared to the average value.

luminance luminance uniformity color uniformity Example 1 103% 1.2 4/1000 Example 2 104% 1.3 4/1000 Example 3 103% 1.3 4/1000 Example 4 104% 1.2 3/1000 Example 5 105% 1.1 2/1000 Example 6 104% 1.1 2/1000 Comparative Example 1 100% 2.1 12/1000

As shown in Tables 1 and 2, in the optical sheet according to the embodiment of the present invention, the thickness uniformity of the polymer resin layer is improved when compared with the optical sheet prepared according to the comparative example, and thus the polymer resin layer is It was confirmed that the luminance and color uniformity of the included optical sheet were also improved.

100: polymer resin layer in which the light emitting material is dispersed
200: spacer
300a, 300b: barrier film
400: barrier material coating layer
500: first roller 550: second roller
600: barrier material supply means
700: spray device

Claims (16)

a first barrier film;
a polymer resin layer formed on the first barrier film and in which a light emitting body is dispersed; and
As an optical sheet comprising; a second barrier film formed on the polymer resin layer,
The polymer resin layer includes one or more spacers,
The spacer includes an acrylic resin,
The total area of the spacer included in the polymer resin layer is 25 to 40% of the total area of the polymer resin layer,
optical sheet. delete delete delete The method of claim 1,
The thickness of the spacer included in the polymer resin layer is 70 to 100% of the thickness of the polymer resin layer optical sheet. The method of claim 1,
The spacer included in the polymer resin layer is an optical sheet spaced apart from each other at intervals of 50 to 300㎛. The method of claim 1,
The cross section of the spacer included in the polymer resin layer is an optical sheet having at least one shape selected from the group consisting of polygons and circles. The method of claim 1,
The cross section of the spacer included in the polymer resin layer is circular,
The spacer is spaced apart from the first barrier film and the second barrier film, and the optical sheet is included in the form of a regular or irregular island in the polymer resin layer. The method of claim 1,
The cross section of the spacer included in the polymer resin layer is rectangular,
The spacer is spaced apart from the first barrier film and the second barrier film, and the optical sheet is included in the form of a regular or irregular island in the polymer resin layer. The method of claim 1,
The cross section of the spacer included in the polymer resin layer is circular,
The spacer is in contact with the first barrier film, and is included in the form of a regular or irregular island on the plane of the first barrier film. The method of claim 1,
The cross section of the spacer included in the polymer resin layer is rectangular,
The spacer is in contact with the first barrier film, and is included in the form of a regular or irregular island on the plane of the first barrier film. The method of claim 1,
The light emitting material is an optical sheet of at least one non-cadmium-based quantum dot selected from the group consisting of group II-VI, group III-V, group IV-VI and group IV semiconductor. The method of claim 1,
The thickness of the polymer resin layer is 10 to 120㎛ optical sheet. The method of claim 1,
The optical sheet further comprising a barrier material coating layer formed on both sides of the first barrier film and the polymer resin layer. (a) preparing a first barrier film;
(b) disposing a second barrier film spaced apart from the first barrier film to face the first barrier film; and
(c) preparing an optical sheet including a polymer resin layer by passing it between laminator rolls while applying a polymer resin crude liquid in which a light emitting body and a spacer are dispersed between the first barrier film and the second barrier film; and ,
The spacer includes an acrylic resin,
The total area of the spacer included in the polymer resin layer is 25 to 40% of the total area of the polymer resin layer,
Optical sheet manufacturing method. (a) dispersing one or more spacers on the first barrier film;
(b) disposing a second barrier film spaced apart from the first barrier film to face the first barrier film; and
(c) preparing an optical sheet including a polymer resin layer by passing it between laminator rolls while applying a polymer resin crude liquid in which a light emitting body is dispersed between the first barrier film and the second barrier film;
The spacer includes an acrylic resin,
The total area of the spacer included in the polymer resin layer is 25 to 40% of the total area of the polymer resin layer,
Optical sheet manufacturing method.

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