KR101102007B1 - Diffusion film improved diffusing and Preparing thereof - Google Patents

Abstract

The present invention is a diffusing film having an improved diffusibility by extrusion stamping method and a method of manufacturing the same, and more particularly, in the multi-layer diffusion film consisting of a surface layer, an intermediate layer and a back layer, the surface layer is embossed unit The present invention relates to a diffusing film having improved structure, and a method of manufacturing the same, wherein a roughness is provided between the unit structure and the unit structure.

Diffuse, illuminance, lenticular, polygonal pyramid, light diffusing agent

Description

Diffusion film improved diffusing and preparing thereof

The present invention relates to a diffusion film having an improved diffusing property and a method of manufacturing the same, and more particularly, to a diffusing film having an improved diffusing property by applying an extrusion engraving manufacturing technique to a light diffusing film for a backlight unit. .

Recently, various flat panel display devices have been developed. These flat panel display devices include liquid crystal displays (LCDs), plasma display panels (PDPs), and field emission displays (FEDs). In addition, studies are being actively conducted to improve the display quality of such flat panel displays.

Among them, LCD is a device that injects liquid crystal between two sheets of glass and applies power to the electrodes installed on the upper and lower glass plates to change the arrangement of liquid crystal molecules and display images in each pixel. Such an LCD display device is usually composed of an LCD panel unit, a driver, and a backlight unit. The LCD panel does not emit light by itself and has only a function of transmitting light on the rear surface. Therefore, in the absence of light, that is, at night or indoors, it is a structure that can not display images without the help of backlight. The backlight unit refers to a system for implementing the backlight of such an LCD.

The backlight unit is largely composed of a lamp, sheets, a mechanism part, and a driving circuit. Since the lamp alone cannot produce uniform light over the entire area, the light guide plate, diffuser plate, reflector plate, prism, frame, etc., sheets and mechanisms are provided.

There are various methods for the backlight unit, and the most widely used method is a cold cathode fluorescent lamp (CCFT) having a light guiding plate (LGP) printed with a reflection pattern in the center by side light method. The cold cathode fluorescent lamp is placed on the edge. At this time, the reflective pattern printed on the light guide plate is printed in a structure to reduce the phenomenon that the brightness difference occurs depending on the position of the lamp is located at the edge of the panel. Although the method of printing the reflective pattern on the light guide plate is high in productivity, the light loss caused by the printing pattern material itself is inferior in efficiency, and the larger the LCD, the worse the uniformity of the overall brightness.

Since the light guide plate method does not provide sufficient brightness, a direct method in which a plurality of lamps are arranged at regular intervals under the diffuser plate is used. In this method, several fluorescent lamps are arranged in a row on the rear surface of the diffusion sheet to improve luminance and improve uniformity than the photometric type. In order to display a bright screen, the backlight source must be very bright. This is because the light from the light source goes through several steps before reaching the LCD, and loses its original brightness in the process. In addition, the uniformity of light throughout the screen is lost because of the scattering effect.

One way to overcome this problem is to increase the size of the light source, but this is expensive installation cost, high power consumption, and also has a problem of increasing the weight a lot. Thus, several attempts have been made to improve the light source brightness without loss as much as possible during the transmission process.

In flat panel display devices such as LCDs and projection TVs, a diffuser is an optical element that plays an important role in reaching light from the light source to the viewer's eyes. The diffuser plate uniformly distributes the light from the light source and plays an important role in the direct type than in the case of LCD. Structural metering is a structure where light guided by a light guide can be uniformly distributed throughout the screen, but in the case of a direct type, several light sources are distributed below the screen, so that the point just above the light source and the point between the light source and the light source Because there is a difference in the light intensity, you have to offset it.

The most important optical properties of the optical film used to improve visibility in the backlight unit are transmittance and haze, which require more than 60% total transmittance and more than 85% blur for visible light. In order to satisfy these characteristics, a light diffusion film generally has a surface diffusion method of refraction or dispersion in many directions using surface roughness and a bulk diffusion film method having an inherent light dispersion element.

The surface diffusion type diffusion film uses a rough surface exposed to air to maximize the difference in refractive index between the material of the diffusion film and the surrounding medium as much as possible to spread the incident light at the largest angle. For example, light diffusivity is imparted by forming irregularities on the film surface. There is a light diffusing film in which the unevenness is formed on the surface of the transparent resin made of a polyester resin, a polymethyl methacrylate resin or a polycarbonate resin. However, it is difficult to simultaneously obtain excellent light transmittance and light diffusivity only by imparting irregularities to the surface by embossing or sand blasting. In addition, the temperature in the backlight unit generally rises from 80 ° C to 90 ° C, and when the humidity is high, shape deformation may occur severely, so that a material having excellent optical properties while having high heat resistance and low moisture absorption rate is used.

The bulk diffusion film is a light diffusing agent such as fine particles dispersed within the film, and is usually made of a transparent resin made of a resin such as polymethyl methacrylate, polycarbonate, etc., calcium carbonate, titanium dioxide, glass beads, silica particles, polystyrene There are light diffusing plates in which particles, silicone resin particles, crosslinked polymer particles and the like are dispersed.

Regarding the method of using surface roughness, which is a method of using unevenness in the film, Korean Laid-Open Patent Publication No. 2007-0026524 discloses an optical film, a light-diffusion film, a manufacturing method thereof, and a method of using the same. An optical film containing 80% by weight or more of carbonate was made to have a mean surface roughness of 0.5 µm or more on the surface to impart a diffusion effect. However, the patent has a problem in diffusibility because the viewing angle is narrow.

Accordingly, it is desired to develop a diffusion film having a wide viewing angle due to improved diffusibility.

In order to solve the above problems, an object of the present invention is to provide a diffused film with a broad line shielding ability and viewing angle.

It is another object of the present invention to provide a diffusion film having improved diffusibility and a method for manufacturing the same, which can be manufactured in a desired stamp shape by controlling the residual stress of a polymer that is a material of the diffusion film.

Still another object of the present invention is to provide a diffusion film having improved physical properties as an optical film such as brightness, transparency, blur, etc., and a method of manufacturing the same.

In order to achieve the above object, the present invention provides a multi-layered diffusion film consisting of a surface layer, an intermediate layer and a back layer, wherein the surface layer includes an embossed unit structure, and roughness between the unit structure and the unit structure. Provided is a diffusion film with improved diffusibility, characterized in that is given.

In another aspect, the present invention provides a diffusing film having an improved roughness is provided to the back layer.

In another aspect, the present invention provides a diffusing film having an improved diffusibility, characterized in that the unit structure is a lens or polygonal pyramid shape.

In another aspect, the present invention provides a diffusion film having an improved diffusibility, characterized in that the polygonal pyramid has a square pyramid shape.

In another aspect, the present invention provides a diffusion film having an improved roughness, the Rz value is 4 to 10㎛, Ra value is 1 to 2㎛, provided to the surface layer or the back layer.

In another aspect, the present invention provides a diffusing film having an improved diffusibility, characterized in that the surface layer is uniformly arranged in close contact with the same size of the unit structure.

In another aspect, the present invention provides a diffusing film having an improved diffusibility, characterized in that the diameter of the lens layer of the surface layer is 30 to 60㎛.

In another aspect, the present invention provides a diffusion film having the interlayer is 10 to 90% by weight of copolyester and 10 to 90% by weight of polycarbonate as a blend or composition of copolyester and polycarbonate.

In the present invention, the intermediate layer is methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, normal butyl methyl methacrylate, acrylic acid, methacrylic acid, hydroxyethyl methacrylate, hydride Monomer selected from oxypropyl methacrylate, hydroxyethyl acrylate, acrylamide, metalolacrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, normal butyl acrylate and 2-ethylhexyl acrylate Diffusion improved diffusion further comprising one or more selected light diffusing particles consisting of beads and silicone-based spherical particles made of homopolymers, copolymers or terpolymers, polyethylene, polystyrene, polypropylene, acrylic and olefin copolymers Provide a film.

In another aspect, the present invention provides a method for producing a diffusion film, comprising: melt-extruding a polymer resin into three layers of a surface layer, an intermediate layer, and a back layer on a film; Etching the extruded film to the surface layer such that roughness is imparted between the embossed unit structure and the unit structure; And it provides a method for producing a diffusion film with improved diffusibility comprising the step of cooling the stamped film.

In another aspect, the present invention provides a method for producing a diffusion film having improved diffusivity, characterized in that the roughness is additionally given to the back layer in the step of engraving the film.

In another aspect, the present invention provides a method for producing a diffusing film having an improved diffusibility, characterized in that the unit structure is a lens shape or a polygonal pyramid shape.

In another aspect, the present invention provides a method for producing a diffusing film having an improved diffusibility, characterized in that the polygonal pyramid has a square pyramid shape.

In another aspect, the present invention provides a method for producing a diffusing film having an improved diffusing property, wherein the cooling step is quenched, but quenched with 4 to 20 ° C. cooling air.

In addition, the roughness imparted to the surface layer or the back layer of the present invention provides a method for producing a diffusing film having an improved diffusibility, wherein the Rz value is 4 to 10 μm and the Ra value is 1 to 2 μm.

In another aspect, the present invention provides a method for producing a diffusing film having an improved diffusing property, characterized in that the shape of the surface layer unit structure is uniformly arranged in the same size.

In another aspect, the present invention provides a method for producing a diffusing film having an improved diffusibility, characterized in that the diameter of the lens layer of the surface layer is 30 to 60㎛.

In another aspect, the present invention provides a method for producing a diffusing film having an improved diffusibility, wherein the intermediate layer comprises 10 to 90% by weight of copolyester and 10 to 90% by weight of polycarbonate as a blend or composition of copolyester and polycarbonate. .

In the present invention, the intermediate layer is methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, normal butyl methyl methacrylate, acrylic acid, methacrylic acid, hydroxyethyl methacrylate, hydride Monomer selected from oxypropyl methacrylate, hydroxyethyl acrylate, acrylamide, metalolacrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, normal butyl acrylate and 2-ethylhexyl acrylate Diffusion improved diffusion further comprising one or more selected light diffusing particles consisting of beads and silicone-based spherical particles made of homopolymers, copolymers or terpolymers, polyethylene, polystyrene, polypropylene, acrylic and olefin copolymers It provides a method for producing a film.

Diffusion film according to the present invention is produced by applying the extrusion stamping manufacturing technology, excellent diffusion and shielding function and has a wide viewing angle effect.

In addition, the diffusion film and the manufacturing method of the improved diffusing property according to the present invention can be produced in the desired stamping shape to reduce the defective rate of the product and has a good shape reproducibility effect.

In addition, the diffusion film and the manufacturing method of the improved diffusing property according to the present invention has the effect of improving the optical properties as an optical film, such as brightness, transparency, blurring.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, it should be noted that in the drawings, the same components or parts denote the same reference numerals as much as possible. In describing the present invention, detailed descriptions of related well-known functions or configurations are omitted in order not to obscure the subject matter of the present invention.

As used herein, the term "film" is used to mean a film, sheet, plate, or the like having a predetermined width and thickness.

In addition, the term "lens shape" is used to mean a lenticular or hemispherical lens shape.

In addition, "roughness" means surface roughness.

The present invention is a multi-layer diffuser film consisting of a surface layer, an intermediate layer and a back layer, wherein the surface layer comprises an embossed unit structure, the roughness is provided between the unit structure and the unit structure, and optionally Roughness is provided to the back layer.

The surface layer includes an embossed unit structure, and the unit structure is preferably in the shape of a lens or a polygonal pyramid. Moreover, in a polygonal pyramid shape, it is more preferable that it is a square pyramid shape.

In the present specification, for example, the shape of the unit structure is described as a lens shape, but the present invention is not limited thereto, and the present invention may be applied without limitation to the polygonal pyramid shape.

1 is a cross-sectional view showing a diffusion film according to an embodiment of the present invention, Figure 2 is a manufacturing process diagram of the diffusion film according to a preferred embodiment of the present invention, the unit structure is a lens shape It is shown as.

The diffusion film may include a surface layer 110, an intermediate layer 120, and a back layer 130. In the surface layer, roughness is provided between the unit structure and the unit structure. Since the roughness is provided between the unit structure and the unit structure, the scattering effect of the light is higher than that of the film not provided with the roughness, thereby improving diffusibility.

In addition, the present invention is to produce a diffusion film by applying the extrusion stamping manufacturing technology, the film extruded from the T-die 210 is to be given the roughness 111 between the lens shape and the lens shape through the relief pattern 231 of the pattern roll 230. Can be. In addition, optionally, the shape of the back layer 130 may be provided with roughness 131 by the first roller 220. The roughness may be provided by sanding the pattern roll and the first roller.

Diffusion film according to the present invention is provided with a multi-layer diffusion film of the melt extrusion stamping method, in the manufacturing process diagram of Figure 2 film having three layers each of the surface layer 110, the intermediate layer 120 and the back layer 130 in the T-die 210 Is extruded. In the pattern roll 230, the engraving pattern 231 has a shape in which the roughness 111 can be imparted between the lens shape and the lens shape in the surface layer 110. In addition, in the engraving pattern 221 of the first roller 220, the roughness 131 may be selectively applied to the back surface layer 130 when the engraving is performed.

The illuminance 111 is provided between the lens shape and the lens shape of the surface layer 110 to enhance the light scattering effect, and the illuminance 131 of the back layer 130 is provided to provide a shielding effect through the light scattering effect. The roughness (111, 131) is preferably provided so that the Rz value is 4 to 10㎛, Ra value is 1 to 2㎛. Within this range, the shielding function is more effectively generated, and defects due to stains, etc., generated during processing are reduced, and scratches are generated during processing and moving means.

The film having the three layers (surface layer, middle layer, and back layer) is extruded and passed between the first roller 220 and the pattern roll 230 to pass between the lens shape and the lens shape in the surface layer 110 through the relief pattern 231 of the pattern roll 230. Roughness 111 is provided, and roughness 131 is applied to the surface of the back layer 130 through the engraving pattern 221 of the first roller 220. (Area A)

Thereafter, the diffusion film is cooled between the pattern roll 230 and the second roller 240, and is cooled in the region B between the pattern roll 230 and the second roller 240 (see FIG. 2). To this end, by forming a quenching condition in the B region to drastically lower the surface temperature of the film, by limiting the flow of the polymer chain due to residual stress as the film is cured to minimize the possibility of shape change will be.

Specifically, the surface of the embossed shape may be further provided with a cooling means such as an air knife to fix the shape expressed on the film. At this time, the cooling temperature is preferably 4 to 20 ℃, more preferably 4 to 10 ℃.

Figure 3 is a photograph of the diffusion film given the roughness produced by the preferred embodiment of the present invention. Roughness is provided between the lens shape and the lens shape in the surface layer, and a plurality of the same size are arranged uniformly.

In addition, Figure 4 shows the position of the lens shape in the diffusion film produced according to an embodiment of the present invention, the lens shape is arranged uniformly while forming an angle of 60 ° in the form of an equilateral triangle when connecting the origin of the round shape Can be.

On the other hand, the diameter of the lens shape of the surface layer 110 is preferably 30 to 60㎛. Within the above range, the light condensing effect is excellent, but when the diameter exceeds 60 μm, moiré phenomenon occurs, and the lens shape of less than 30 μm has a small diameter, which causes processing limitations.

On the other hand, the polymer film of the surface layer 110 in the diffusion film may be a polycarbonate, a non-limiting example is preferably an aromatic polycarbonate and more preferably bisphenol-A [2,2-bis (4-hydroxyphenyl ) Propane] may be a polycarbonate. A material having a benzoyl group may be added to the polycarbonate to prevent yellowing due to ultraviolet rays. Non-limiting examples of the benzoyl group include benzotriazol, benzoxazinone, and benzotriazole.

In addition, the back layer 130 may be made of the same material as the surface layer 110 to prevent yellowing due to ultraviolet rays generated from the lamp.

In addition, the material of the polymer resin of the intermediate layer 120 may be made of a blend or composition of copolyester and polycarbonate, and may specifically include 10 to 90% by weight of copolyester and 10 to 90% by weight of polycarbonate. However, the present specification is described as the material, but is not limited thereto.

The material of the intermediate layer 120 may preferably be prepared as a blend or a composition in a specific ratio of copolyester and polycarbonate, and specific ratios include 10 to 90% by weight of copolyester and 10 to 90% by weight of polycarbonate. can do.

The copolyester may be terephthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid or a mixture thereof as the acid component, and ethylene glycol and 1,4-cyclohexanedimethanol (CHDM) may be used as the glycol component. . Non-limiting examples of suitable copolyesters include poly (1,4-cyclohexylenedimethylene terephthalate) (PCT), poly (1,4-cyclohexylenedimethylene naphthalenedicarboxylate) (PCN), poly (1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate) (PCC) can be used.

The material has a feature that the process moisture content is relatively low to maintain shape stability even at high humidity.

Meanwhile, the intermediate layer 120 may further include light diffusing particles. Since the light diffusing particles should be compatible with a binder (resin) containing particles, organic particles having a similar refractive index to materials and spherical silicon particles having a low refractive index may be used. In this case, inorganic particles having a refractive index of 1.50-1.80 can be used. Particularly, the particle selection to be used is advantageous for solving the problem such as showing the bright line due to the spherical particles whose refractive index difference is 0.1 to 0.2 from the material to increase the shielding ability, and can maximize the diffusion effect with a relatively small particle amount. It is very advantageous.

The refractive index of the diffusing agent particles used increases the light diffusion effect as the difference between the material and the refractive index is larger, but when the refractive index difference is too large, it is disadvantageous in terms of increasing the brightness, so that the proper refractive index difference is obtained and sometimes similar to the material. It is preferable to use the particle | grains with a big difference.

Non-limiting examples of light diffusing particles that can be used in the present invention include methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, normal butyl methyl methacrylate, acrylic acid, methacrylic acid, Hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, acrylamide, metalolacrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, normal butyl acrylate and 2 Homopolymers, copolymers or terpolymers of monomers selected from ethylhexyl acrylate, beads made from copolymers of polyethylene, polystyrene, polypropylene, acrylics and olefins, and silicone-based spherical particles may be used. Preferably, the material is spherical particles between 1 micron and 10 microns having a refractive index difference of about 0.1 to about 0.2. Spherical organic particles having such a refractive index difference can be easily dispersed in the resin because they have densities similar to those of the material used in the present invention (about 1.10 to 1.30 g / cm 3).

The light diffusing particles used in the present invention may use different ones in type and / or size. For example, light diffusion efficiency can be enhanced by mixing two or more kinds of particles having a difference in refractive index rather than a single type. In addition, light diffusing efficiency may be increased by using particles having similar refractive indices and different sizes, and by applying porous particles, the brightness may be increased while maximizing light diffusing efficiency after assembling the backlight unit.

Using particles of uniform particle size requires a large amount of particles to produce a predetermined light diffusing effect, which results in not only economic inefficiency, but also lowering the overall transmittance. According to one embodiment of the present invention, the size of the light diffusing particles can be used to increase the light diffusion effect while reducing the particle content by using two kinds of particles of size 20 to 30 microns and 1 to 15 microns.

The light diffusing particles may be used at 0.5 to 20% by weight, preferably 1 to 10% by weight, based on the total weight of the interlayer resin. When the light-diffusing particles are 0.5% by weight or less, a predetermined light-diffusion effect cannot be obtained. When the light-diffusing particles are more than 20% by weight, the light transmittance is lowered and the dispersibility of the particles is lowered to obtain uniform particle dispersion.

As mentioned above, the material of the intermediate layer 120 has a property of lowering the glass transition temperature (Tg) of the polycarbonate and the copolyester as a blend or a composition, compared to the surface layer 110 made of the polycarbonate. As the transition temperature is lower than the surface layer 110, the dimensional stability is improved.

Hereinafter, embodiments of the present invention will be described in detail.

Example 1

A polycarbonate resin containing bisphenol-A [2,2-bis (4-hydroxyphenyl) propane] was used as the resin for the surface layer and the back layer, and benzoxazinone materials were added. As the resin of the intermediate layer, a polycarbonate-based resin containing a polyester-based resin mainly containing 1,4-cyclohexanedicarboxylic acid and bisphenol-A [2,2-bis (4-hydroxyphenyl) propane] It was mix | blended in the ratio of 1: 1, and it mixed and mixed methylmethacrylate as 15 weight% of the weight of resin of an intermediate | middle layer as a light-diffusion agent. Subsequently, the resin was produced by screw coextrusion at 270 ° C., and the lens shape was the same size, the diameter was 30 μm, the height of the lens shape was 12 μm, and between the lens shape and the lens shape of the surface layer. The diffusion film was manufactured by operating a sanding operation and a patterned roll so that the roughness was 6 µm and the average Ra value was 1.0 µm.

Example  2

The same process as in Example 1, except that the diameter of the lens shape was 60㎛ and the height was 27㎛ to manufacture a diffusion film by operating a pattern roll.

Example  3

The same procedure as in Example 1 was applied, but the roughness was also applied to the back layer, and the sanding operation, the pattern roll, and the first roller were operated so that the roughness of the back layer was given a Rz value of 6 µm and an average Ra value of 1.0 µm. To prepare a diffusion film.

Example  4

The same process as in Example 1, but the roughness was also applied to the back layer, the surface layer and the back layer by operating the pattern roll and the first roller so that the Rz value is 10㎛, the average Ra value 2.0㎛ is applied to the diffusion film Was prepared.

Comparative example  1 and 2

In the same manner as in Examples 1 and 2, the diffusion film was prepared without imparting roughness to the diffusion film surface layer and the back layer.

* Test Methods

1. Transmittance (TT), Haze and Diffusion (DT): Measured by ASTM D1003 method using NIPPON DENSHOKU 300A analytical equipment in Japan.

2. Luminance: Measure the film on the stage equipped with TOPCON BM-7 under the conditions of 16.5V and Dimming value of 2.8V with CCFL voltage mounted on backlight unit (diffusion plate-diffusion film-prism-diffusion film). .

Table 1 shows the results of testing optical characteristics such as transmittance for each of Examples and Comparative Examples.

division Transmittance (%) Haze (%) Diffusion transmittance (%) Brightness (cd / m 2) Example 1 69.16 89.42 61.84 9830 Example 2 69.37 89.37 62.01 9810 Example 3 69.29 89.39 61.92 9820 Example 4 69.47 89.44 62.13 9840 Comparative Example 1 58.04 85.54 49.65 9880 Comparative Example 2 57.59 85.68 49.26 9860

As a result of experiment, even if roughness was applied to the surface layer and back layer, there was no significant change in luminance.As a result of applying roughness to the surface layer and back layer, the haze was improved by about 4% and the shielding force was increased. It was confirmed that there is a scattering effect was increased by 12%.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. It will be clear to those who have knowledge of.

Figure 1 shows a cross-sectional view of the diffusion film produced by the preferred embodiment of the present invention.

Figure 2 shows a schematic view of the manufacturing process of the diffusion film according to an embodiment of the present invention.

Figure 3 shows a schematic perspective view of the diffusion film produced by the preferred embodiment of the present invention.

Figure 4 shows the position of the lens shape in the diffusion film produced by the preferred embodiment of the present invention.

Claims (19)

In the diffusion film of the multi-layer structure consisting of a surface layer, an intermediate layer and a back layer, The surface layer includes an embossed unit structure, Roughness is provided between the unit structure and the unit structure, Roughness is additionally given to the back layer, The roughness imparted to the surface layer and the back layer has a Rz value of 4 to 10 µm and a Ra value of 1 to 2 µm. delete The method of claim 1, The unit structure is a diffusing film having an improved diffusibility, characterized in that the lens shape or polygonal pyramid shape. The method of claim 3, The polygonal pyramid diffuser film characterized in that the rectangular pyramid shape. delete The method of claim 1, The surface layer is a diffusing film having an improved diffusing property, characterized in that the unit structure is uniformly arranged in close contact with the same size. The method of claim 3, Diffusion film with improved diffusivity, characterized in that the diameter of the lens layer of the surface layer is 30 to 60㎛. The method of claim 1, The interlayer is a blend or composition of the copolyester and polycarbonate diffusion film containing 10 to 90% by weight of copolyester and 10 to 90% by weight of polycarbonate. The method of claim 1, The intermediate layer is methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, normal butyl methyl methacrylate, acrylic acid, methacrylic acid, hydroxyethyl methacrylate, hydroxypropyl methacrylate Homopolymers of monomers selected from latex, hydroxyethyl acrylate, acrylamide, metarollacrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, normal butyl acrylate and 2-ethylhexyl acrylate, A diffuser film having improved diffusivity, further comprising at least one light diffusing particle comprising a bead made of a copolymer or terpolymer, polyethylene, polystyrene, polypropylene, an acrylic and an olefin copolymer, and silicon-based spherical particles. In the manufacturing method of the diffusion film, Melt-extruding the polymer resin into three layers of a surface layer, an intermediate layer, and a back layer on a film; Roughening the extruded film so that roughness is provided between the embossed unit structure and the unit structure, and the roughness is further imparted to the back layer; And Including cooling the stamped film, The roughness applied to the surface layer or the back layer is Rz value of 4 to 10㎛, Ra value of 1 to 2㎛ manufacturing method of the diffusion film with improved diffusing property. delete The method of claim 10, The unit structure is a method of manufacturing a diffusing film, characterized in that the lens shape or polygonal pyramid shape improved. The method of claim 12, The polygonal pyramid has a rectangular pyramid shape, characterized in that the diffusion film manufacturing method with improved diffusing ability. The method of claim 10, The cooling step is quenching, but the method of producing a diffused film having an improved diffusing property, characterized in that the quenching with cooling air of 4 to 20 ℃. delete The method of claim 10, The surface layer is a method of manufacturing a diffusing film, characterized in that the unit structure is uniformly arranged in the same size. The method of claim 12, The diameter of the lens layer of the surface layer is a method for producing a diffusing film having an improved diffusing property, characterized in that 30 to 60㎛. The method of claim 10, The intermediate layer is a blend or composition of the copolyester and polycarbonate 10 to 90% by weight of the copolyester and 10 to 90% by weight of the polycarbonate containing the improved diffusion method for producing a film. The method of claim 10, The intermediate layer is methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, normal butyl methyl methacrylate, acrylic acid, methacrylic acid, hydroxyethyl methacrylate, hydroxypropyl methacrylate Homopolymers of monomers selected from latex, hydroxyethyl acrylate, acrylamide, metarollacrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, normal butyl acrylate and 2-ethylhexyl acrylate, Method for producing a diffuser film having improved diffusibility further comprising at least one light diffusing particle consisting of a bead made of a copolymer or terpolymer, polyethylene, polystyrene, polypropylene, acryl and olefin copolymer and silicon-based spherical particles .

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