KR20070064846A - Preparing method of light diffusion sheet for backlight unit - Google Patents

Abstract

A method for manufacturing a light diffusing sheet for a backlight unit is provided to improve the brightness of the light diffusing sheet by forming the light diffusing sheet to have no beads therein, and widen the light viewing angle by increasing the light diffusing property of the light diffusing sheet. A light curable resin material film is formed on one of a pattern roll or a pattern belt, and a transparent base. The pattern roll or the pattern belt has a cylindrical metal sheet fixed on a surface thereof, wherein the cylindrical metal sheet has a plurality of hemisphere-shaped concave portions having different sizes. The light curable resin material film is contacted with the other of the pattern roll or the pattern belt, and the transparent base. A press-hardening process is performed on the light curable resin material film, thereby forming a transparent base film having hemisphere-shaped convex portions. The transparent base film is released from the pattern roll or the pattern belt. In order to obtain the cylindrical metal sheet, firstly, a base layer, in which a plurality of beads having different sizes are laid, is wound around a cylindrical frame while a bead layer of the base layer is used as an inner layer. A joint between both sides of the base layer wound around the cylindrical frame is connected and fixed, and the cylindrical frame is removed. A metal layer is formed on the bead layer of the base layer, and is released from the base layer.

Description

Manufacturing method of light diffusion sheet for backlight unit {PREPARING METHOD OF LIGHT DIFFUSION SHEET FOR BACKLIGHT UNIT}

1 is a schematic cross-sectional view showing the configuration of a conventional backlight unit,

2 is a schematic diagram showing a manufacturing process of a metal sheet according to the present invention,

3A and 3B schematically illustrate a method of manufacturing a light diffusion sheet using a pattern roll and a pattern belt according to the present invention, respectively.

4 is a schematic cross-sectional view (a) and a top view (b) showing a light diffusing sheet manufactured according to the present invention.

The present invention relates to a light diffusion sheet used in a backlight unit of a liquid crystal display and a manufacturing method thereof.

A liquid crystal display (LCD) is a kind of light that displays numbers or images by generating contrast by injecting a liquid crystal, which is an intermediate material between a solid and a liquid, between two thin glass plates and changing the arrangement of liquid crystal molecules by the voltage difference between the electrodes on the upper and lower glass plates. It is a device using a switch phenomenon. The passive matrix method and the active matrix method are classified according to the driving method. The passive matrix method includes TN (Twisted Nematic) and STN (Super Twisted Nematic) methods, and the active matrix method includes TFT (Thin Film Transistor) method. LCDs are widely used in electronic products such as electronic clocks, calculators, liquid crystal TVs, and notebook PCs for speed displays and driving systems of automobiles and aircrafts.

The advantages of such LCDs are low power consumption (1/3 of CRT), low operating voltage, and light and thin processability. On the other hand, the LCD has a narrow viewing angle, difficult to implement a large screen, and low temperature operation.

As a core component of the liquid crystal display device, a backlight unit may be used. The backlight unit is used as a dimming device to evenly transmit light to the entire TFT-LCD panel and displays an image with transmitted light.

Unlike CRT, PDP, and FED, the screen display by LCD cannot be used without a light source because the liquid crystal device itself is non-light-emitting, and the device that functions as a light source on the LCD and illuminates the information display surface uniformly is backlighted. Unit.

Since the backlight unit is used as a light source for a monitor TFT-LCD and a notebook, a function that needs to emit the brightest light with the minimum power is required. In addition, the backlight unit should play a role of changing the light emitted from the light source to the surface light by maintaining the same brightness to every corner of the LCD surface.

As shown in FIG. 1, the backlight unit includes a lamp as a light source, a reflector for reflecting light emitted from the lamp, a light guide plate for transmitting light, a mold frame (not shown) for tying components, brightness and It consists of a light diffusion sheet, a panel, etc. which improve the viewing angle.

The backlight unit is a direct method of directly dimming the front surface of the panel by arranging a light source on one side of the panel, and an edge for reflecting / diffusing light on a light guide plate and a reflective sheet by disposing a light source on one side or multiple sides of the panel. ) Is divided into (or side light). Recently, a side light method in which a light source is disposed on at least one side of a liquid crystal display device has been widely used for manufacturing a small electronic device by reducing the weight and thickness of a backlight unit. On the other hand, in recent years, LCDs for TVs use a unit in which a plurality of light sources are disposed under the light source, a light guide plate is disposed thereon, and a diffusion sheet and a prism are stacked thereon.

As a manufacturing method of the light-diffusion sheet used for a backlight unit, the method of apply | coating the binder resin which disperse | distributed the beads on the surface of a base material is proposed (refer Japanese Unexamined-Japanese-Patent No. 5-73602). That is, this manufacturing method provides the light-diffusion sheet | seat of the structure by which the bead containing light-diffusion layer was laminated | stacked on the base material. As the substrate, a film made of polyethylene terephthalate, polyester, polycarbonate synthetic resin, an acrylic resin or glass material as a bead, and an acrylic or urethane synthetic resin as a binder resin were used. However, in the case of using the beads, there is a problem that a defect occurs on the screen by dropping the beads when cutting the light diffusion sheet.

As another method of manufacturing the light diffusion sheet, there is a technique of forming irregularities on the surface of the substrate by embossing the substrate of the synthetic resin material. The manufacturing method by the embossing process requires the production of a roll mold with embossing of several tens of microns, which leads to difficulty in the process itself, and it is not easy to form irregularities on the roll, which exhibits the light diffusing effect, on the roll. It is difficult to obtain sufficiently, and problems such as light unevenness due to the surface pattern are likely to occur.

In addition, in Japanese Patent Laid-Open No. 2000-193805, after laminating an ultraviolet curable resin on top of a substrate, the resin is pressed onto the surface of the substrate, a curing process is performed, and a light diffusion sheet is manufactured by a release process in which the substrate is peeled off. . This method has the advantage of improving the brightness compared to the case of using a bead, but there is a problem that bubbles in the resin occurs when laminating the UV-curable resin, and because the resin film is used, pattern damage easily occurs, it is difficult to use long, Since the opposite side of the disc is duplicated, it is a factor that lowers the luminance in geometrical structure.

SUMMARY OF THE INVENTION An object of the present invention is to overcome the problems of the prior art as described above, and to provide a light diffusion sheet for a backlight unit having excellent luminance characteristics and further increasing the diffusivity in the left and right directions to widen the viewing angle of the exit surface. , There is no problem that the joint part of the mold is not broken and the joint is connected smoothly so that the resin penetrates the joint part to provide a method of manufacturing the product so that there is no product defect due to continuous resin lamination and curing of the hardened part generated after curing. .

In order to achieve the above object, in the present invention, a view on a pattern roll or a pattern belt (A) and a transparent substrate (B) in which a cylindrical metal sheet having a plurality of different hemispherical recesses is fixed on a surface thereof. After coating the chemical resin composition and contacting the coated surface with the other of the above (A) and (B) to perform a compression curing process, the transparent base film formed with a plurality of hemispherical convex portions having different sizes are patterned. And releasing from a roll or a pattern belt, wherein the cylindrical metal sheet is wound around a cylindrical frame with a plurality of beads of different sizes embedded in a cylindrical frame with the inner surface of the bead layer and connected to a joint to fix the cylindrical frame. It is obtained by removing the metal and forming a metal layer on the inner surface with the bead layer and releasing from the transparent substrate in which the beads are embedded. Bit manufacturing method of the light diffusion sheet is provided for the unit.

Hereinafter, the present invention will be described in more detail.

The method of the present invention is characterized in that a light diffusion sheet is produced using a pattern roll or a patterned belt in which a seamless cylindrical metal sheet is fixed to a surface.

The manufacturing method of the present invention is largely, for example, as shown in Figure 2, 1) a plurality of beads of different sizes embedded with a bead layer on the inner surface of the cylindrical frame and connected to the joint to fix the cylinder after Removing the mold, depositing or electroplating a metal layer on the inner surface of the bead layer, and releasing the metal layer from the transparent substrate embedded with beads to produce a cylindrical metal sheet having a plurality of hemispherical recesses having different sizes; 3A and 3B, 2) any one of a pattern roll (FIG. 3A) or a pattern belt (FIG. 3A) (A) and a transparent base material (B) in which the metal sheet obtained in accordance with the above process is fixed to the surface. Coating the photocurable resin composition on the side and performing a curing process while contacting the coated surface with the other side of the above (A) and (B) to release the transparent base film from the pattern roll or the pattern belt. The process consists of.

Looking at the metal sheet manufacturing process in detail as follows.

Specifically, the cylindrical metal sheet according to the present invention, as shown in Figure 2, after embedding a plurality of beads of different sizes by the usual method on the substrate (step 1), the substrate is the inner surface of the bead layer Winding the outside of the cylindrical frame and connecting the joints to fix it (step 2), removing the cylindrical frame and forming a metal layer on the inner surface of the bead layer (step 3), and then releasing the metal layer from the bead embedded substrate (Step 4), it can be obtained in a seamless form having a plurality of hemispherical recesses of different sizes.

In step 1, the bead layer may be formed by coating a polyethylene resin on a transparent film such as polyester and then supplying a plurality of spherical beads having different sizes to the surface while melting the surface of the polyethylene resin.

Alternatively, the bead layer may be formed on a surface of a bead layer formed by coating a polyethylene resin on a transparent film such as polyester and then supplying a plurality of spherical beads having different sizes to the surface while melting the polyethylene resin surface. After applying and curing the fixing binder resin, an adhesive layer is formed on the cured resin, and the support layer is laminated thereon, and thermally compressed to fix the bead layer from the polyethylene resin layer to the support. Can be.

The bead fixing binder resin is not particularly limited as long as it is a material of a conventionally used adhesive component, and specific examples thereof may include acrylic resins, urethane resins, melamine resins, ester resins, benzene resins, and the like. Such a resin can be used a photocuring method or a thermosetting method, the resin layer thickness is preferably 5㎛ to 100㎛. If the thickness is less than 5㎛ not enough adhesive force can be dropped bead, if it exceeds 100㎛ it may be difficult to uniformly apply.

The adhesive layer formed above may be a hot melt adhesive such as EVA (ethylene vinyl acetate), a polyethylene hot melt adhesive, a polyurethane hot melt adhesive, an ethylene-acetic acid hot melt adhesive, polyesters, epoxy resins, Photocurable resins, such as (meth) acrylate type resins, such as polyester (meth) acrylate, epoxy (meth) acrylate, and urethane (meth) acrylate, can be used. The thickness is preferably 0.01 mm to 1 mm. If the thickness is less than 0.01mm, the bead layer may not be sufficiently supported and may be separated during release. If the thickness is greater than 1mm, plating may not be easy.

As a support body used above, normal polyester resin, acrylic resin, polycarbonate resin, vinyl chloride resin, vinylidene fluoride system, polyethylene system, and polypropylene system. As long as it is a supportable material, such as a transparent base material made of polymethacrylamide type resin, a rubber base material, a metal base material, etc., it can use all, It is preferable that the thickness is 0.05 mm-2 mm. When the thickness is less than 0.05mm, the bead layer may not be sufficiently supported and may be separated during release, and when the thickness exceeds 2mm, plating and cutting may not be easy.

The bead-embedded substrate prepared as described above is wound around a cylindrical frame with the bead layer as an inner surface, and is fixed by connecting the joints. Then, the cylindrical frame is removed and a metal layer is formed on the surface on which the beads are formed, for example, by electroplating. At this time, in order to facilitate the electroplating may be performed after the metal thin film is formed on the surface of the bead layer by a silver mirror reaction or deposition. In addition, the metal layer may be a metal material such as nickel, zinc, tin, etc., may further plate the chromium (Cr) and the like, it is preferable to form a thickness of 0.5 to 2.0 mm.

By releasing this metal layer from the bead embedding transparent base material, it is possible to obtain a seamless cylindrical metal sheet having a plurality of hemispherical recesses of different sizes.

Subsequently, the metal sheet is fixed to the surface of the roll or belt to obtain a pattern roll or a pattern-formed belt (A), and the photocurable resin composition on either of the pattern roll or the belt (A) and the transparent substrate (B). The coated surface was contacted with the other of the above (A) and (B) to perform a compression hardening process, and then the transparent base film having the hemispherical convex portion was released from the pattern roll or the patterned belt. The light diffusion sheet according to the present invention can be obtained.

For example, as shown in FIG. 3, the light diffusion sheet according to the present invention is formed on a pattern roll or a patterned belt on which a metal sheet having a plurality of hemispherical recesses having different sizes manufactured by the above method is fixed to a surface thereof. After coating the photocurable resin composition, laminating a transparent substrate thereon and performing a curing process while pressing, the transparent base film may be manufactured by releasing the transparent base film from a pattern roll or a belt on which a pattern is formed.

4 schematically shows the structure of a light diffusion sheet according to a preferred embodiment of the present invention. According to FIG. 4A (cross-sectional view), the photocurable resin layer in which the multiple projection part of the hemispherical shape was formed was laminated | stacked on one surface of the polyethylene terephthalate (PET) film which is a transparent base material, and the space between protrusion parts is laminated | stacked here. Silver, both ends of the projections are formed lower than the base surface can form an arc, this structure further improves the brightness. The transparent substrate may be treated with a primer layer prior to forming the protrusions. FIG. 4B is a top view showing a state in which the protrusions are randomly distributed on the PET substrate in the light diffusion sheet.

In the present invention, the projections of the photocurable resin formed on the transparent substrate is characterized in that they have different sizes in the range of about 10 to 100 ㎛ diameter, these different size projections increase the light diffusion effect brightness And the effect of improving the haze.

It is preferable that such protrusions occupy 50 to 90% of the total surface area of the sheet. In this case, when the filling rate of the protrusions is less than 50%, the luminance decreases, and when the protrusions are larger than 90%, it is impossible due to technical limitations.

The photocurable resin composition may be applied onto a pattern roll or a belt on which a pattern is formed as described above. Alternatively, the photocurable resin composition may be coated on a transparent substrate surface and then laminated on the coating surface so as to contact the pattern roll or a belt on which the pattern is formed. You can also do

The transparent substrate used in the present invention is not particularly limited as long as it is a material that transmits active energy such as ultraviolet rays, visible rays, and electron beams, and specific examples thereof include flexible polyester resins, acrylic resins, polycarbonate resins, vinyl chloride resins, and poly Methacrylamide type resin etc. are mentioned. In particular, polyesters such as polymethyl methacrylate, polymethyl acrylate and a mixture of polyvinylidene fluoride resin, polycarbonate resin and polyethylene terephthalate, which have a lower refractive index than the refractive index of the pattern portion and have a lower surface reflectance. It is preferable to use resin. 50-200 micrometers is suitable for the thickness of such a transparent base material.

The photocurable resin used in the present invention is not particularly limited as long as it is cured by active energy rays such as ultraviolet rays and electron beams, and specific examples thereof include polyesters, epoxy resins, polyester (meth) acrylates, and epoxy (meth) s. (Meth) acrylate type resins, such as an acrylate and a urethane (meth) acrylate, etc. are mentioned. Of these, (meth) acrylate resins are particularly preferred from the viewpoint of optical properties and the like. The photocurable resin preferably has a refractive index in the range of 1.24 to 1.60.

The photocurable resin composition for producing such a photocurable resin is a polyhydric acrylate and / or a polyhydric methacrylate (hereinafter referred to as polyvalent (meth) acrylate), monoacrylate, and / Or monomethacrylate (hereinafter referred to as mono (meth) acrylate) and a photopolymerization initiator as a main component. Representative polyvalent (meth) acrylates include polyol poly (meth) acrylates, polyester poly (meth) acrylates, epoxy poly (meth) acrylates, urethane (meth) acrylates, or mixtures thereof. . As mono (meth) acrylate, monoalcohol mono (meth) acrylic acid ester, polyol mono (meth) acrylic acid ester, etc. can also be used. In the latter case, when using a metal type, due to the influence of free hydroxyl groups, It is preferable to use it in small quantity in order to reduce mold release difficulty with the metal mold | type considered, and when using a metal mold | die, since it has high polarity also about (meth) acrylic acid and its metal salt, it is good to use it in small quantity.

The coating method may be any method that can be commonly used in the field of the present invention, but preferably, a roll coating method using gravure roll, reverse gravure roll, micro gravure roll, or the like, using mayer bar, die coating, or the like The bar coating method and the coating method using an air knife can be used.

In addition, in the present invention, the photocurable resin composition is preferably coated on a pattern roll or a patterned belt or a transparent substrate with a thickness of 5 to 50 μm, and the coating amount is on the patterned roll or the belt on which the pattern is formed. It may vary depending on the size of the hemispherical recess on the metal sheet to be fixed.

According to a preferred embodiment of the present invention, in order to improve coating properties and adhesion performance with the photocurable resin on one surface of the transparent substrate, an anchor coat treatment, a primer treatment using an organic solvent, or a primer layer using a water dispersible composition. It is more effective to form it.

Preferred resins for forming the primer layer are thermosetting polyurethane resins, which are prepared by condensation polymerization of saturated or unsaturated dicarboxylic acids with alkylene glycols having 2 to 8 carbon atoms, and reacting a polyisocyanate with a polyester polyol containing active hydrogen atoms. It is prepared by forming a precursor and reacting the precursor with bisulfite salts of alkali or alkaline earth metals.

At this time, the polyester polyol is saturated or unsaturated dicarboxylic acid, such as succinic acid, adipic acid, sebacic acid, phthalic acid, maleic acid, and ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, neopentyl glycol and hexylene It is prepared by polycondensing alkyleneglycols such as glycol and the like. Examples of the polyisocyanate include 2,4- or 2,6-tolylene diisocyanate, xylene diisocyanate, 4,4-diphenylmethane diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate And aliphatic diisocyanate.

In addition, the primer layer further includes conventional inorganic lubricants such as silica, alumina, talc and the like to improve the activity and winding property, and if necessary, antistatic agents, wetting agents, pH adjusting agents, antioxidants, dyes, pigments, slips. Other additives such as agents may be further included within the scope of not impairing the effects of the present invention.

On the other hand, it is preferable that the thickness of the said primer layer is 0.001-1 micrometer, and content of the polyurethane in a primer layer is 0.01-0.5 g / m <^2> . If the thickness of the primer layer is less than 0.001 μm, the coating property is poor, whereas if the thickness of the primer layer is more than 1 μm, the adhesion with the laminated or coated polymer resin may be deteriorated.

The light diffusion sheet of the present invention prepared as described above has a level of 80 to 95% of haze, and when the haze is less than 80%, a desired diffusion effect cannot be obtained, and when it exceeds 95%, sufficient luminance cannot be obtained. none. In addition, the preferred light transmittance of the light diffusion sheet according to the present invention is 50 to 75%, when the transmittance is less than 50% can not be obtained high luminance, if it exceeds 75% can not expect the diffusion effect.

The light diffusion sheet according to the present invention has no beads due to continuous resin lamination and curing of the hardened portion generated after the resin is soaked into the joint portion due to the rough seam, and does not include beads. Compared with the sheet, high luminance can be obtained, and there is no need to manufacture a mold having a special structure as in the embossing method, and there is no problem of breakage of the joint part of the mold, which can prevent product defects due to mold damage. The bubble generation problem caused by the method of directly laminating the resin can be drastically reduced.

Hereinafter, a concrete embodiment of the present invention will be described in more detail. The following examples are merely illustrative to assist in understanding the present invention and are not intended to limit the scope of the present invention.

Example 1

Forming a polyethylene coating layer on a 125 μm-thick polyethylene terephthalate film (manufactured by SH-71 SKC) and applying heat at 120 ° C., spraying glass beads having different diameters in the range of 30 to 60 μm thereon, It was pressed to contain beads on a PET film. The glass bead-compressed PET film was wound on a cylindrical mold with the bead layer as an inner surface, and then the seam was fixed with an adhesive tape, and after removing the mold and depositing silver on the bead, the Ni-plated thin film was formed by electroplating. To 1.5 mm thick. After the bead embedded transparent substrate was released from the metal sheet, a pattern roll was prepared by fixing the metal sheet on the roll surface.

A transparent PET film coated with a refractive index of 1.49 and an ultraviolet curable resin (WOW149, manufactured by WOW Chemical) at a thickness of 20 μm on the pattern roll, and coated with a thermosetting polyurethane resin at a thickness of 0.03 μm (SH-71, manufactured by SKC) The step of laminating and then pressing was carried out to perform a curing process by an ultraviolet curing lamp to form a plurality of protrusions of ultraviolet curable resin on the transparent PET film.

Example 2

The same process as in Example 1 was performed except that an ultraviolet curable resin (A-BPE-10, manufactured by NK ESTER) having a refractive index of 1.52 was used as the photocurable resin.

Example 3

The same process as in Example 1 was performed except that an ultraviolet curable resin (U-06, manufactured by KYOEISHA) having a refractive index of 1.55 was used as the photocurable resin.

Example 4

The same process as in Example 1 was performed except that an ultraviolet curable resin (WOW157, manufactured by Wow Chemical) having a refractive index of 1.57 was used as the photocurable resin.

Example 5

The same process as in Example 1 was carried out except that an ultraviolet curable resin (U-60, manufactured by Shin-Nakamura, Japan) having a refractive index of 1.47 was used as the photocurable resin.

Comparative example

According to a conventional method for producing a light diffusion sheet, 21.4 parts by weight of acridic AA-960-50 (Aekyung Chemical) as a binder and 41.4 parts by weight of n-butyl acetate as a solvent and Brunnock DN-950 (Aekyung Chemical) as a curing agent After dissolving 2.9 parts by weight, 30.3 parts by weight of Techpolymer MBX-15 (Sekisui), a light diffusing agent, was added with stirring to prepare a dispersion. Thereafter, the dispersion liquid prepared above was coated on one surface of a transparent PET film (SH-71, manufactured by SKC Co., Ltd.) coated with a thermosetting polyurethane resin with a thickness of 0.03 μm in a thickness of 10 μm, and then thermally cured at 100 to 120 ° C. To make a light diffusion sheet.

Test Example

Haze, light transmittance and luminance were measured for the light diffusing sheets prepared from Examples 1 to 4 and Comparative Examples, and the results are shown in Table 1 below. In this case, the luminance was measured by using a luminance meter (BM-7) for each sheet and two sheets, respectively, and haze and light transmittance using a hazemeter (NDH 5000, manufactured by Densho Kogyo Co., Ltd.). It was measured by.

From Table 1, it can be seen that the light diffusion sheet of the present invention is generally excellent in terms of haze, light transmittance, and luminance.

The light diffusion sheet of the present invention has no roughness due to the rough seam, and does not contain beads, and thus has higher brightness than the light diffusion sheet, and there is no problem such as foreign matter mixing due to the dropping of beads when cutting the sheet. By increasing the diffusivity, the wide viewing angle can be widened.

Claims (11)

The photocurable resin composition is coated on any one of a pattern roll or a pattern belt (A) and a transparent substrate (B) having a cylindrical metal sheet having a plurality of different hemispherical recesses on the surface thereof, and the coating surface is coated with ( Performing a press hardening process by contacting with the other surface of A) and (B), and then releasing the transparent base film having a plurality of hemispherical convex portions having different sizes from a pattern roll or a pattern belt, wherein Wherein the cylindrical metal sheet, a plurality of beads of different sizes are embedded in a cylindrical frame with the bead layer as the inner surface, and fixed by connecting the joint, remove the cylindrical frame and form a metal layer on the inner surface with a bead layer A method for producing a light-diffusion sheet for a backlight unit, wherein the bead is obtained by releasing from a buried transparent substrate. The method of claim 1, Method for producing a light diffusion sheet for a backlight unit, characterized in that the metal layer is formed through electroplating after the silver diameter reaction. The method of claim 1, Method for producing a light diffusion sheet for a backlight unit, characterized in that the metal layer is formed through electroplating after metal deposition. The method of claim 1, Characterized in that the substrate is embedded with a plurality of beads of different sizes, by coating a polyethylene resin on a transparent film and then supplying a plurality of spherical beads of different sizes to the surface while melting the polyethylene resin surface, Manufacturing method of light diffusion sheet for backlight unit The method of claim 1, A substrate having a plurality of beads of different sizes embedded therein is coated with a polyethylene resin on a transparent film, and then the surface of the polyethylene resin is melted to supply a plurality of spherical beads of different sizes to the surface to form a bead layer. It is produced by applying and curing the binder resin for fixing the bead on the bead layer surface, forming an adhesive layer on the cured resin, laminating the substrate thereon and thermocompressing, and then releasing the polyethylene resin layer. Manufacturing method of light diffusion sheet for unit The method of claim 1, A method for producing a light diffusion sheet for a backlight unit, characterized in that the metal sheet is made of a nickel or a nickel / chromium composite layer. The method of claim 1, The metal sheet has a thickness of 0.5 to 2 mm, the manufacturing method of the light diffusion sheet for a backlight unit. The method of claim 1, The photocurable resin composition contains a mono (meth) acrylate, a polyvalent (meth) acrylate, and a photoinitiator, The manufacturing method of the light-diffusion sheet for backlight units. The method of claim 1, The photocurable resin composition is coated by the thickness of 5-50 micrometers, The manufacturing method of the light-diffusion sheet for backlight units. The method of claim 1, It uses after forming a primer layer in a transparent base film, The manufacturing method of the light-diffusion sheet for backlight units characterized by the above-mentioned. The method of claim 10, The primer layer is formed by coating a thermosetting polyurethane resin.

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