KR20100056349A - The optical film, back light unit and liquid crystal display comprising thereof - Google Patents

Abstract

PURPOSE: An optical film, a back light unit, and a liquid crystal display comprising thereof are provided to improve the diffusion and the luminance characteristic of the optical film by forming a protrusion with creation roughness on the surface. CONSTITUTION: An optical film(100) comprises a base part(110) and a protrusion(120). The protrusion is located on the base part. The protrusion comprises a plurality of micro lenses(121), a plurality of groove portions(122), and a remaining area(123). A plurality of groove portions are arranged around of a plurality of micro lenses. The average surface roughness(Ra) of a plurality of micro lenses is between 0.3~1.5um. The base part and protrusion more include a diffusion particle.

Description

Optical film, back light unit and liquid crystal display including the same {The Optical Film, Back Light Unit And Liquid Crystal Display Comprising Thereof}

The present invention relates to an optical film, and more particularly, to an optical film, a backlight unit and a liquid crystal display device including the same.

Recently, the display field for visually expressing various electrical signal information is rapidly developing, and in response to this, various flat panel displays (FPDs) with excellent characteristics such as thinness, light weight, and low power consumption are being developed. It is introduced and rapidly replaced the existing CRT (Cathode Ray Tube).

Examples of such flat panel displays include liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), and electroluminescence displays (ELDs). The liquid crystal display has a large contrast ratio and is excellent in moving image display, and is currently used most widely in the field of display screens, monitors, and TVs for notebook computers.

In general, a liquid crystal display device classified as a light receiving display device may include a backlight unit disposed below the liquid crystal panel to provide light to the liquid crystal panel in addition to the liquid crystal panel displaying an image.

The backlight unit may include a light source, an optical sheet, and the like to provide light to the liquid crystal panel. Here, the optical sheet may include a diffusion sheet, a prism sheet or a protective sheet.

Such a backlight unit is composed of an optical sheet made up of a plurality of sheets for diffusing and condensing light emitted from a light source, but there are many limitations in achieving improvement in manufacturing yield and brightness of the backlight unit.

Therefore, this invention provides the optical film which can improve brightness and can prevent a bright line from generate | occur | producing.

In order to achieve the above object, the optical film according to an embodiment of the present invention is located on the base portion and the base portion, a plurality of micro lenses, a groove portion located around the plurality of micro lenses and the plurality of micro lenses And a protrusion including a remaining area except for the plurality of grooves, the average surface roughness Ra of the plurality of micro lenses may be 0.3 to 1.5 μm.

In addition, the backlight unit according to an embodiment of the present invention includes a light source and an optical film positioned on the light source, the optical film is located on the base and the base, a plurality of micro lenses, the plurality of micro lenses Including a groove portion located in the vicinity of the projections including the remaining portion other than the plurality of micro lenses and the plurality of grooves, the average surface roughness (Ra) of the plurality of micro lenses may be 0.3 to 1.5㎛.

In addition, the liquid crystal display according to an exemplary embodiment of the present invention includes a light source, an optical film positioned on the light source, and a liquid crystal panel positioned on the optical film, and the optical film is positioned on the base and the base. And a plurality of micro lenses, grooves positioned around the plurality of micro lenses, and protrusions including the plurality of micro lenses and the remaining areas except for the plurality of grooves, and the average surface roughness of the plurality of micro lenses ( Ra) may be 0.3 to 1.5 μm.

The optical film of the present invention has an advantage of improving the diffusion and luminance characteristics of the optical film by forming a protrusion having a certain surface roughness.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1A to 1C are views illustrating an optical film according to a first embodiment of the present invention.

Referring to FIG. 1A, the optical film 100 according to the first embodiment of the present invention is positioned on the base 110 and the base 110, and includes a plurality of micro lenses 121 and a plurality of micro lenses ( It may include a plurality of grooves 122 positioned around the 121 and a protrusion 120 including the plurality of micro lenses 121 and the remaining areas 123 except for the plurality of grooves 122.

The base 110 supports the optical film 100 and serves to transmit the light incident from the light source. The base 110 may use polystyrene (PS), polyacrylate (PA), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), etc., but in optical applications, it is 1.56 to Polycarbonate (PC) with a refractive index of 1.58 may be most preferred.

The protrusion 120 may be located on the base 110. The protrusion 120 may be integrated with the base 110 and may be made of the same material as the base 110.

The protrusions 120 may include a plurality of micro lenses 121, a plurality of grooves 122 positioned around the plurality of micro lenses 121, and a plurality of micro lenses 121 and the plurality of grooves 122. It may include the remaining area 123 except for.

Protruding portion 120 serves to collect or diffuse light, polystyrene (PS), polyacrylate (PA), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), etc. However, polycarbonate (PC) having a refractive index of 1.56 to 1.58 may be most preferable in optical applications.

The plurality of micro lenses 121 may be formed to have an embossed hemisphere.

The microlens 121 may vary the degree of diffusion, the degree of refraction, the light condensation, etc. according to the size and the density of the lens. Accordingly, the pitch P between the micro lenses 121 may be 25 to 75 μm. In addition, the microlens 121 may have a constant or irregular diameter of the lens, and the height of the lens may also be constant or irregular.

Accordingly, the lens diameter of the microlens 121 may be 20 to 60 μm, but is not limited thereto. The distribution of the lens in the total area may be formed to have 50 to 90% or more, but is not limited thereto. In addition, the height difference between the micro lenses 121 may be 5 μm or less, but is not limited thereto.

When the microlens 121 is formed to have an embossed hemisphere as described above, some of the light incident from the outside, for example, the bottom of the microlens 121 is uniform at all azimuth angles in the hemisphere. It may be refracted to pass through the micro lens 121. For this reason, some of the light incident from the lower portion of the microlens 121 may be uniformly diffused upward and may be focused.

Meanwhile, the average surface roughness Ra of the micro lens 121 may be 0.3 to 1.5 μm. Here, when the average surface roughness Ra of the microlens 121 is 0.3 µm or more, there is an advantage that the diffusion property of the optical film can be improved, and the average surface roughness Ra of the microlens 121 is 1.5 µm or less. If it is, there exists an advantage which can improve the brightness characteristic of an optical film.

Next, the microlens 121, the groove 122, and the remaining region 123 of the optical film 100 according to the first exemplary embodiment of the present invention will be described with reference to FIG. 1B.

A plurality of grooves 122 are positioned around the plurality of micro lenses 121.

The groove 122 may have an average surface roughness Ra of 0.1 to 3 μm, but is not limited thereto. In addition, the width of the groove 122 may be 1 to 5㎛, but is not limited thereto.

The groove 122 may be positioned over the entire circumference of the plurality of micro lenses 121, and the groove 122 may be located at a portion of the circumference of the plurality of micro lenses 121.

The remaining area 123 except for the plurality of micro lenses 121 and the plurality of grooves 122 may be located.

The remaining area 123 may be flat or have a predetermined roughness to areas other than the microlens 121 and the groove 122. Here, when the remaining area 123 has a certain roughness, the average surface roughness may be 0.1 to 3 μm, but is not limited thereto.

On the other hand, referring to Figure 1c, unlike the above, the base portion 110 of the optical film 100 according to the first embodiment of the present invention is made of a curved surface of the lower surface 111 of the base portion 110 winding It may be. The curved surface may be formed at regular intervals, but is not limited thereto. Here, the bottom surface 111 of the base 110 may have an average surface roughness (Ra) of 1 to 5㎛.

As described above, the optical film 100 according to the first embodiment of the present invention may exhibit an effect of diffusing light incident from the bottom in the base 110, and condenses and diffuses the light incident from the protrusion 120. By doing so, there is an advantage of improving the brightness and uniformity of the light at the same time.

2A and 2B illustrate an optical film according to a second embodiment of the present invention.

Referring to FIG. 2A, the optical film 200 is positioned on the base portion 210 and the base portion 210, and includes a plurality of micro lenses 221 and a plurality of micro lenses 221 located around the plurality of micro lenses 221. The protrusion 220 may include a groove 222, a plurality of micro lenses 221, and a remaining area 223 except for the plurality of grooves 222.

The average surface roughness Ra of the microlens 221 may be 0.3 to 1.5 μm, the average surface roughness Ra of the groove 222 may be 0.1 to 3 μm, and the width of the groove 222 may be wide. It may be 1 to 5㎛ not limited thereto. In addition, the average surface roughness of the remaining area 223 may be 0.1 to 3 μm, but is not limited thereto.

On the other hand, the optical film 200 according to the second embodiment of the present invention may further include a plurality of diffusion particles 230 in the base portion 210 and the protrusion 220.

The diffusion particles 230 may be made of any one or more selected from the group consisting of silicon, polymethyl methacrylate, and polycarbonate.

In addition, the diffusion particles 230 may be made of a particle diameter of 1 to 20㎛. The size of the diffusion particles 230 may be the same each, and its distribution may be regular. Alternatively, the size of the diffusion particles 230 may be different from each other, the distribution may be irregular.

As described above, the diffusion particles 230 may diffuse light incident from a light source, thereby improving luminance uniformity.

On the other hand, referring to Figure 2b, unlike the above, the base portion 210 of the optical film 200 according to the second embodiment of the present invention is made of a curved surface of the lower surface 211 of the base portion 210 winding It may be. The curved surface may be formed at regular intervals, but is not limited thereto. Here, the bottom surface 211 of the base portion 210 may have an average surface roughness Ra of 1 to 5 μm.

Therefore, the optical film 200 according to the second embodiment of the present invention further includes diffused particles 230 in the optical film 200, thereby providing improved light diffusion characteristics in addition to the effects in the first embodiment. There is an advantage to this.

3A and 3B illustrate an optical film according to a third embodiment of the present invention.

Referring to FIG. 3A, the optical film 300 is positioned on the base 310 and the base 310, and is positioned around the plurality of micro lenses 321 and the plurality of micro lenses 321. The protrusion 320 may include a plurality of grooves 322, a plurality of micro lenses 321, and a remaining area 323 except for the plurality of grooves 322.

In a third embodiment of the present disclosure, the base portion 310 may further include a first base region 315 and a second base region 316 positioned below the first base region 315.

Here, the second base region 316 may further include a plurality of diffusion particles 330.

The diffusion particles 330 may be made of any one or more selected from the group consisting of silicon, polymethyl methacrylate, and polycarbonate.

In addition, the diffusion particles 330 may be made of a particle diameter of 1 to 20㎛. The size of the diffusion particles 330 may be the same, and the distribution thereof may be regular. Alternatively, the size of the diffusion particles 330 may be different from each other, the distribution may be irregular.

The diffusion particles 330 as described above have an advantage of improving brightness uniformity by diffusing light incident from a light source.

Here, the second base region 316 and the first base region 315 may be determined by the presence or absence of the diffusion particles 330 in the base portion 310, which is located at the top from the bottom of the base portion 310 The area up to the diffusion particles 330 is defined as the second base area 316, and the area until the protrusion 320 starts from the end of the diffusion particle 330 located at the top is defined as the first base area 315. It can be defined as.

Accordingly, the thickness T2 of the second base region 316 may be 5 to 20% of the total thickness T1 of the optical film 300.

The protrusion 320 may be located on the base 310, and as in the above-described embodiments, the average surface roughness Ra of the micro lens 321 of the protrusion 320 may be 0.3 to 1.5 μm. . In addition, the average surface roughness Ra of the groove 322 may be 0.1 to 3 μm. In addition, the width of the groove 322 may be 1 to 5㎛, but is not limited thereto. In addition, the average surface roughness of the remaining area 323 may be 0.1 to 3㎛, but is not limited thereto.

4A to 4D are views illustrating an optical film according to a fourth embodiment of the present invention.

4A and 4B, the optical film 400 of the present invention is positioned on the base 410 and the base 410, and includes a plurality of micro lenses 421 and a plurality of micro lenses 421. The projection part 420 may include a groove part 422 positioned at a periphery and a plurality of micro lenses 421 and a remaining area 423 except for the groove part 422.

In the fourth exemplary embodiment of the present invention, the base portion 410 may further include a first base region 415 and a second base region 416 disposed below the first base region 415. Here, the first base region 415 and the protrusion 420 may further include a plurality of diffusion particles 430.

The diffusion particles 430 may be made of any one or more selected from the group consisting of silicon, polymethyl methacrylate (PMMA), and polycarbonate (PC).

In addition, the diffusion particles 430 may have a particle diameter of 1 to 20㎛. The size of the diffusion particles 430 may be the same, respectively, the distribution may be regular. Alternatively, the size of the diffusion particles 430 may be different from each other, the distribution may be irregular.

As described above, the diffusion particles 430 may diffuse light incident from a light source, thereby improving luminance uniformity.

Here, the second base region 416 and the first base region 415 may be determined by the presence or absence of the diffusion particles 430 in the base portion 410, which is located at the bottom from the bottom of the protrusion 420 A region up to the diffused particles 430 may be defined as the first base region 415, and a region where the base 410 ends from the end of the diffused particles 430 positioned at the lowermost portion may be defined as the second base region 416. Can be.

Accordingly, the thickness ratio T2: T1 of the thickness T2 of the second base region 416 and the total thickness T1 of the optical film 400 may be 1:20 to 1: 5.

On the other hand, as in the above-described embodiments, the bottom surface 411 of the base portion 410 may be made of a flat surface. On the other hand, as shown in Figure 4b, the lower surface 411 of the base portion 410 may be made of a curved surface.

The average surface roughness Ra of the microlens 421 may be 0.3 to 1.5 μm. In addition, the average surface roughness Ra of the groove 422 may be 0.1 to 3 μm, and the width may be 1 to 5 μm, but is not limited thereto. In addition, the average surface roughness of the remaining area 423 may be 0.1 to 3㎛, but is not limited thereto.

In addition, the optical films according to the first to fourth embodiments of the present invention described above may be formed with the same size or different from each other, as shown in FIGS. 4A and 4B. However, the present invention is not limited thereto. In addition, the bottom surface 411 of the base may be flat, alternatively it may be made of a curved surface and the average surface roughness (Ra) may be 1 to 5㎛.

Hereinafter, the manufacturing method of the optical film according to the embodiments of the present invention described above are as follows.

5A and 5B are views showing a manufacturing method of the optical film of the present invention.

Referring to FIG. 5A, the first resin 501 and the second resin 502 are coextruded. More specifically, the first resin 501 is provided to the first extruder 510, the material of the second resin 502 is provided to the second extruder 520, and coextruded simultaneously.

In this case, the material of the first resin 501 and the second resin 502 may be polystyrene (PS), polyacrylate (PA), PMMA, polycarbonate (PC), polyethylene terephthalate (PET), etc. For optical applications, polycarbonates having a refractive index of 1.56 to 1.58 may be most preferred.

Here, polycarbonate pellets may be used as the materials of the first resin 501 and the second resin 502. Pellets refer to solidified particles of a material, which may be larger than powder.

Such pellets may be formed by mixing each resin with additives such as antioxidants and UV additives together.

In addition, the first resin 501 or the second resin 502 may include diffusion particles. The first resin 501 and the second resin 502 form an optical film formed later, and may include diffusion particles, thereby contributing to the diffusion of light.

At this time, if the diffusion particles are not added to the first resin 501 or the second resin 502, the same structure as the first embodiment of the present invention can be formed, the first resin 501 and the second resin ( When the diffusion particles are added to 502, the same structure as in the second embodiment of the present invention is formed, and when the diffusion particles are added only to the first resin 501, the optical film having the same structure as in the third embodiment of the present invention is obtained. It becomes possible to manufacture.

Here, the diffusion particles may be made of any one or more selected from the group consisting of silicon, polymethyl methacrylate and polycarbonate, and may be used having a particle diameter of 1 to 20㎛.

The first extruder 510 and the second extruder 520 are provided with internal temperature conditions of 280 to 300 ° C., and when the respective resin pellets are provided, the first extruder 510 and the second extruder 520 are melted through each extruder tube 511 and 521. The first resin 501 and the second resin 502 are discharged.

Next, the extruded first resin 501 and the second resin 502 are introduced into the adapter 525 through the extrusion pipes 511 and 521. The adapter 525 serves to control the number of extruders. When two extruders are used as in this embodiment, two inlets may be used, and in the case of three extruders, three inlets may be used. . Therefore, the adapter 525 may be replaced according to the number of extruders, thereby making it an efficient process.

Subsequently, the co-extruded first resin 501 and the second resin 502 have a first roll 530 having a flat surface 531 and a second roll 540 having a first structured surface 541. Rolling simultaneously through to form an optical film 560 having a protrusion 556 and a base 555.

In more detail, when the above-mentioned first resin 501 and the second resin 502 are extruded through each of the extruded pipes 511 and 521, the first resin 501 and the second resin 502 are combined and extruded. .

The first roll 530 and the second roll 540 have a surface temperature of about 90 to 100 ° C., so that the first resin 501 is rolled between the first roll 530 and the second roll 540. The temperature of the second resin 502 can be quenched and solidified.

The extruded first resin 501 and the second resin 502 are passed between the first roll 530 and the second roll 540 to roll, thereby forming an optical film having a protrusion 556 and a base 555. 560 can be formed.

Here, the first roll 530 has a flat surface 531 and the second roll 540 has a first structured surface, where the first structured surface 541 can be the inverse of the micro lens.

Here, the second roll 540 is formed by coating the surface of the roll with nickel (Ni), recoating with ceramic, and then processing the first structured surface 541 of the second roll 540 by using a laser. Can be.

At this time, when the laser is irradiated to the surface of the roll, the ceramic in the area irradiated with the laser is melted to form a reversed phase of the microlens, and the ceramics of the portion flow upward. Accordingly, the surface of the second roll 540 may be formed to have a certain roughness on the surface when the molten ceramics remain intact to form a micro lens later.

Accordingly, the optical film 560 rolled by the first roll 530 and the second roll 540 includes a plurality of micro lenses, a plurality of grooves positioned around the plurality of micro lenses, and the plurality of micro lenses. And a protrusion 556 and a base 555 including the remaining areas except for the plurality of grooves.

That is, a flat surface is formed on one surface of the optical film 560 by the flat surface 531 of the first roll 530, and the other surface of the optical film 560 is the first structured surface of the second roll 540. The reversed phase of 541 is formed so that the protrusion 556 having a micro lens shape is formed.

More specifically, the coextruded first resin 501 and the second resin 502 are made of a first roll 530 having a second structured face 532 and a first having a first structured face 541. Simultaneously rolling through two rolls 540, an optical film 560 having a protrusion 556 and a base 555 comprising a curved surface can be formed.

Here, the second structured surface 532 of the first roll 530 may be a serpentine curved shape. Accordingly, an inverted phase of the second structured surface 532 of the first roll 530 is formed on one surface of the optical film 560, that is, the bottom surface of the base, so that a tortuous curved surface can be formed. In this case, the curved surface of the optical film 560 may have an average surface roughness Ra of 1 to 5 μm.

As described above, the optical film 560 including the base 555 and the protrusion 556 may be formed.

Hereinafter, the experimental example which measured the diffusion characteristic and the brightness characteristic according to the average surface roughness of the micro lens of the optical film of this invention mentioned above is disclosed. However, the experimental examples disclosed below are only examples and the present invention is not limited thereto.

Experimental Example

A first resin pellet comprising a polycarbonate resin and an additive was provided to the first extruder, and a second resin pellet of the polycarbonate resin was provided to the second extruder and coextruded.

Next, it rolled with the 1st roll which has a curved surface, and the 2nd roll which has a surface of a micro lens reverse phase, and formed two or more micro lenses whose average surface roughness Ra of the micro lens of an optical film is 0.1 micrometer.

Then, after forming a plurality of optical films so that the average surface roughness (Ra) of the microlenses are 0.1 0.3, 0.5, 0.7, 0.9, 1.1, 1.3, 1.5 and 1.7 ㎛ each 0.2㎛ interval, Diffusion characteristics and luminance were measured and shown in Table 1 below.

Average surface roughness (Ra) of microlenses (μm) Diffusion characteristics Luminance 0.1 × ◎ 0.3 ○ ○ 0.5 ○ ○ 0.7 ◎ ○ 0.9 ◎ ○ 1.1 ◎ ○ 1.3 ○ ○ 1.5 ○ ○ 1.7 ○ ×

                                   ×: bad, ○: good, ◎: very good

Referring to Table 1, it can be seen that the diffusion effect of the optical film is improved when the average surface roughness Ra of the microlens of the present invention is 0.3 µm or more. However, it can be seen that the luminance characteristic is lowered while the average roughness Ra exceeds 1.5 µm.

In addition, it can be seen that the diffusion effect of the optical film when the average surface roughness (Ra) of the microlenses is 0.7 to 1.1 m is better.

6A and 6B are exploded perspective views and cross-sectional views illustrating a configuration of a backlight unit including an optical film according to embodiments of the present disclosure.

In FIG. 6A, an edge type backlight unit is illustrated as the backlight unit, and the overlapping description is omitted since the optical film of the present invention is the same as the above-described optical sheet.

6A and 6B, the backlight unit 600 according to an exemplary embodiment of the present invention may be provided in the liquid crystal display device and may provide light to the liquid crystal panel provided in the liquid crystal display device.

The backlight unit 600 may include a light source 620 and an optical film 630. In addition, the backlight unit 600 may further include a light guide plate 640, a reflective plate 650, a bottom cover 660, and a mold frame 670.

The light source 620 may generate light using driving power applied from the outside, and may emit the generated light.

For example, at least one light source 620 may be formed on one side of the light guide plate 640 along the long axis direction of the light guide plate 640, or at least one light source 620 may be formed on each side of the light guide plate 640. . Here, the light emitted from the light source 620 is incident directly into the light guide plate 640, or the light source housing 622 formed to surround a portion of the light source 620, for example, about 3/4 of the outer peripheral surface of the light source 620. After reflection, the light guide plate 640 may be incident into the light guide plate 640.

The light source 620 may include, for example, a Cold Cathode Fluorescent Lamp (CCFL), a Hot Cathode Fluorescent Lamp (HCFL), an External Electrode Fluorescent Lamp (EEFL), and a Light Emitting Diode. It may be one of (Light Emitting Diode: LED), but is not limited thereto.

The optical film 630 may be disposed on the light guide plate 640. The optical film 630 may serve to condense the light incident from the light source 620.

The optical film 630 may include a base portion, a plurality of micro lenses, a plurality of grooves positioned around the plurality of micro lenses, and a protrusion including a remaining area except for the plurality of micro lenses and the plurality of grooves.

The light guide plate 640 may be disposed to face the light source 620, and may guide the light so that light incident from the light source 620 is emitted upward.

The reflective plate 650 may be disposed under the light guide plate 640, and may reflect light emitted downward through the light guide plate 640 from the light emitted from the light source 620.

The bottom cover 660 may include a bottom part 662 and a side part 664 formed to extend from the bottom part 662 to form an accommodation space, and the light source 620 and the optical film 630 may be formed in the accommodation space. The light guide plate 640 and the reflective plate 650 may be accommodated.

The mold frame 670 may be formed in a substantially rectangular frame shape and may be fastened to the bottom cover 660 in a top down manner from an upper side of the bottom cover 660.

7A and 7B are exploded perspective views and cross-sectional views for describing the configuration of a backlight unit according to an embodiment of the present invention. 7A and 7B illustrate a direct backlight unit as the backlight unit, but the present invention is not limited thereto. Meanwhile, the backlight unit illustrated in FIGS. 7A and 7B is substantially the same as the backlight unit illustrated in FIGS. 6A and 6B except for the arrangement of the light sources and the change in the components thereof, and thus, redundant descriptions thereof will be omitted. Only its features will be described.

7A and 7B, the backlight unit 700 according to an exemplary embodiment of the present invention may be provided in the liquid crystal display device and may provide light to the liquid crystal panel provided in the liquid crystal display device.

The backlight unit 700 may include a light source 720 and an optical film 730.

In addition, the backlight unit 700 may further include a reflector 750, a bottom cover 760, a mold frame 770, and a diffuser plate 780.

At least one light source 720 may be disposed under the diffuser plate 780. For this reason, the light emitted from the light source 720 may be incident directly to the diffusion plate 780.

The optical film 730 may be disposed on the diffuser plate 780. The optical film 730 may serve to condense the light incident from the light source 720.

The optical film 730 may include a base portion, a plurality of micro lenses, a plurality of grooves positioned around the plurality of micro lenses, and a protrusion including a remaining area except for the plurality of micro lenses and the plurality of grooves.

The diffusion plate 780 may be disposed between the light source 720 and the optical film 730, and may diffuse the light incident from the light source 720 upward. This is to prevent the shape of the light source 720 from being visible through the backlight unit 700 and to further diffuse the light.

8A and 8B are exploded perspective views and cross-sectional views illustrating a structure of a liquid crystal display according to an exemplary embodiment of the present invention. 8A and 8B illustrate the backlight unit illustrated in FIGS. 6A and 6B as the backlight unit, but the present invention is not limited thereto. The backlight unit illustrated in FIGS. 7A and 7B may be employed as the backlight unit. Meanwhile, since the backlight units illustrated in FIGS. 8A and 8B are the same as described above, overlapping descriptions are omitted and only the features thereof will be described.

8A and 8B, the liquid crystal display 800 according to an exemplary embodiment may display an image by using the electro-optical characteristics of the liquid crystal. The liquid crystal display 800 may include a backlight unit ( 810 and a liquid crystal panel 910.

The backlight unit 810 may be mounted under the liquid crystal panel 910 and may provide light to the liquid crystal panel 910.

The backlight unit 810 may include a light source 820 and an optical film 830. In addition, the backlight unit 810 may further include a light guide plate 840, a reflective plate 850, a bottom cover 860, and a mold frame 870.

The liquid crystal panel 910 may be seated on the mold frame 970 and may be fixed by the top cover 920 fastened to the bottom cover 960 in a top-down manner.

The liquid crystal panel 910 may display an image using light provided from the backlight unit 810, specifically, light emitted from the light source 820.

The liquid crystal panel 910 may include a color filter substrate 912 and a thin film transistor substrate 914 facing each other with the liquid crystal interposed therebetween.

The color filter substrate 912 may implement colors of an image displayed through the liquid crystal panel 910.

The color filter substrate 912 may include a color filter array formed of a thin film on a transparent substrate such as glass or plastic, for example, a red / green / blue color filter. Here, the upper polarizer may be disposed on the color filter substrate 912.

The thin film transistor substrate 914 is electrically connected to the printed circuit board 818 on which a plurality of circuit components are mounted through the driving film 816. The thin film transistor substrate 914 may apply a driving voltage provided from the printed circuit board 818 to the liquid crystal in response to a driving signal provided from the printed circuit board 818.

The thin film transistor substrate 914 may include a thin film transistor and a pixel electrode formed of a thin film on another substrate 914 of a transparent material such as glass or plastic.

Here, a lower polarizer may be attached to the lower portion of the thin film transistor substrate 914.

As described above, the optical film according to the embodiments of the present invention has the advantage that the mass production is possible by improving the production yield by forming the optical film by the extrusion method.

In addition, by forming an optical film having a base having a curved surface and a protrusion, there is an advantage that can efficiently focus light. Therefore, there is an advantage that can provide an optical film that can improve the brightness of light.

In addition, by forming the optical film including a plurality of diffusion particles, it is possible to prevent the bright lines appearing brighter in the brightness of the region where the light source is located there is an advantage that can improve the reliability of the optical film.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the above-described technical configuration of the present invention may be embodied in other specific forms by those skilled in the art to which the present invention pertains without changing its technical spirit or essential features. It will be appreciated that it may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

1A to 1C illustrate an optical film according to a first embodiment of the present invention.

2A and 2B show an optical film according to a second embodiment of the present invention.

3A and 3B illustrate an optical film according to a third embodiment of the present invention.

4A to 4D illustrate an optical film according to a fourth embodiment of the present invention.

5A and 5B illustrate a method of manufacturing an optical film according to embodiments of the present invention.

6A and 6B illustrate a direct backlight unit according to an embodiment of the present invention.

7A and 7B illustrate an edge type backlight unit according to an exemplary embodiment of the present invention.

8A and 8B illustrate a liquid crystal display according to an exemplary embodiment of the present invention.

Claims (19)

Base; And Located on the base portion, and includes a plurality of micro lenses, a groove portion located around the plurality of micro lenses and a projection including a remaining area except the plurality of micro lenses and the plurality of grooves, The average surface roughness Ra of the plurality of micro lenses is 0.3 to 1.5 μm. The method of claim 1, The base and the protrusions further comprise diffusing particles. The method of claim 1, And the base and the protrusions are integral and made of the same material. The method of claim 1, The base portion further comprises a first base region and a second base region located below the first base region. The method of claim 4, wherein And said second base region of said base portion further comprises diffusion particles. The method of claim 4, wherein And the first base region and the protrusion further comprise diffusing particles. The method according to any one of claims 2, 5 and 6, The particle size of the diffusion particles is 1 to 20㎛ optical film. The method of claim 4, wherein The thickness ratio of the second base region and the optical film is 1:20 to 1: 5. The method of claim 1, The average surface roughness Ra of the groove part is 0.1 to 3 μm. The method of claim 1, The average surface roughness (Ra) of the remaining area is 0.1 to 3㎛ optical film. The method of claim 1, The diameter of the micro lens is 20 to 60㎛ optical film. The method of claim 1, The pitch of the micro lens is 25 to 75㎛ optical film. The method of claim 1, The height difference between the micro lenses is less than 5㎛. The method of claim 1, The optical film is made of any one selected from the group consisting of polystyrene (PS), polyacrylate (PA), polymethyl methacrylate (PMMA), polycarbonate (PC) and polyethylene terephthalate (PET). 15. The method of claim 14, The refractive index of the polycarbonate (PC) is 1.56 to 1.58 optical film. The method of claim 1, The lower surface of the base portion is an optical film that is a curved surface. The method of claim 1, The lower surface of the said base part has an average surface roughness Ra of 1-5 micrometers. Light source; And An optical film positioned on the light source, The optical film has a base; And Located on the base portion, and includes a plurality of micro lenses, a plurality of grooves located around the plurality of micro lenses and a projection including a remaining region other than the plurality of micro lenses and the plurality of grooves, An average surface roughness Ra of the plurality of micro lenses is 0.3 to 1.5 μm. Light source; An optical film positioned on the light source; And It includes a liquid crystal panel positioned on the optical film, The optical film has a base; And Located on the base portion, and includes a plurality of micro lenses, a plurality of grooves located around the plurality of micro lenses and a projection including a remaining region other than the plurality of micro lenses and the plurality of grooves, The average surface roughness Ra of the plurality of micro lenses is 0.3 to 1.5 μm.

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