KR20100036656A - Optical sheet, back light unit and liquid crystallization display comprising of the same - Google Patents

Abstract

PURPOSE: An optical sheet, a backlight unit, and an LCD device thereof are provided to improve the reliability of a display device by improving the wet-proof property, the heat resistance, and the durability of an optical sheet. CONSTITUTION: A protrusion(120) is located in the single-side of a material(110). A coating unit(130) is located in the other side of the materials. A primer layer is included between the materials and the protrusion. The protrusion comprises a plurality of beads. The cross section of the protrusion can be a prism part with a triangular prism shape. The protrusion includes peaks(121) and valleys(122). The peak and the valleys can be formed to the direction which is same with the longitudinal direction of the protrusion.

Description

Optical Sheet, Back Light Unit And Liquid Crystallization Display Comprising Of The Same}

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

In recent years, as the society enters the information age in earnest, the display field that visually expresses various electrical signal information is rapidly developing, and in response to this, it has excellent characteristics such as thinning, light weight, and low power consumption. Various flat panel display devices (FPDs) have been introduced to quickly replace the existing cathode ray tube (CRT).

Specific examples of such a flat panel display include a liquid crystal display (LCD), a plasma display panel (PDP), a field emission display (FED), an electroluminescent display ( Electroluminescence Display Device (ELD), etc. The LCD has a large contrast ratio and shows excellent characteristics in moving image display, and is currently being used most actively in the display screen, monitor, and TV field for notebooks.

The liquid crystal display device is a passive device using a backlight unit on the back of the substrate, and the backlight unit is composed of a fluorescent lamp and various optical sheets. The optical sheet can focus or diffuse light emitted from the backlight unit due to very fine prisms.

However, the optical sheet is susceptible to heat and moisture, and may cause wrinkles in a high temperature and high humidity environment, and researches to improve moisture resistance and heat resistance of the optical film are actively underway.

Accordingly, the present invention provides an optical sheet capable of improving moisture resistance, heat resistance and durability, a backlight unit including the same, and a liquid crystal display device.

In order to achieve the above object, the optical sheet according to an embodiment of the present invention includes a substrate, a protrusion located on one side of the base material and a coating part located on the other side of the base material, the fluorine-based acrylate Can be.

In addition, the backlight unit according to an embodiment of the present invention includes a light source and an optical sheet positioned on the light source, the optical sheet is located on the substrate, a protrusion located on one side of the substrate and the other surface of the substrate, It may include a coating comprising a fluorine-based acrylate.

In addition, the liquid crystal display according to an exemplary embodiment of the present invention includes a light source, an optical sheet positioned on the light source, and a liquid crystal panel positioned on the optical sheet, wherein the optical sheet is positioned on one surface of the substrate. Located on the other side of the protruding portion and the substrate, and may include a coating portion containing a fluorine-based acrylate.

An optical sheet, a backlight unit including the same, and a liquid crystal display device according to an exemplary embodiment of the present invention have an advantage of improving reliability of a display device by improving moisture resistance, heat resistance, and durability of the optical sheet.

Hereinafter, an optical sheet, a backlight unit including the same, and a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1A to 1E are views illustrating an optical sheet according to an embodiment of the present invention.

First, referring to FIGS. 1A to 1C, an optical sheet 100 according to an embodiment of the present invention may be a substrate 110 and a protrusion 120 and the substrate 110 positioned on one surface of the substrate 110. Located on the other side of the, may include a coating 130 containing a fluorine-based acrylate.

The substrate 110 serves to transmit the light incident from the light source. To this end, since the substrate 110 must be able to transmit light incident from the light source, any one selected from the group consisting of a light transmissive material, for example, polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polystyrene, and polyepoxy It may be made of one, but not limited to.

The substrate 110 may be formed to a thickness of 10 to 1000㎛. Here, when the thickness of the substrate 110 is 10 μm or more, there is an advantage that the mechanical strength and thermal stability of the film can be secured. When the thickness of the substrate 110 is 1000 μm or less, the mechanical strength and thermal stability of the film may be improved. There is an advantage that can maintain the flexibility of the film while ensuring.

The protrusion 120 may be located on one surface of the substrate 110, and the protrusion 120 may serve to collect or diffuse light incident from the light source.

The protrusion 120 may be made of a transparent polymer resin to transmit light incident from the outside. Here, the polymer resin may be any one selected from the group consisting of acrylic, polycarbonate, polypropylene, polyethylene, and polyethylene terephthalate.

The protrusion 120 may be a prism portion whose cross section is a triangular prism shape. Here, as shown in FIG. 1A, the protrusion 120 includes a peak 121 and a valley 122, and the peak 121 and the valley 122 are straight in the same direction as the length direction of the protrusion 120. Can be made.

Here, the distance P between the peaks 121 of the protrusion 120 may be 20 to 60 μm, and the angle A of the peak 121 may be 70 to 110 °. In addition, the height (H) of the protrusion 120 may be the same as the height of the mountain 131, it may be 10 to 40㎛.

In addition, as shown in FIGS. 1B and 1C, the peaks 121 or valleys 122 of the protrusions 120 may form continuous bends in the longitudinal direction of the protrusions 120, which are regular or irregular. Can be.

That is, the peak 121 of the protrusion 120 may have a zigzag shape in which the left and right sides are random, and the average horizontal amplitude of the peak 121 may be 1 to 20 μm.

In addition, the valleys 122 of the protrusions 120 may have a zigzag shape in which the left and right sides are random, and the average horizontal amplitude of the valleys 122 may be 1 to 20 μm.

In addition, the height of the peak 121 of the protrusion 120 may vary continuously from each bottom surface, it may be made a regular or irregular bend. At this time, the average height difference of the peaks 121 of the protrusion 120 may be 1 to 20㎛.

Meanwhile, referring to FIG. 1D, the coating part 130 may be made of a fluorine acrylate resin obtained by synthesizing a fluorine-based material with an acrylic resin. Fluorine can be synthesized in the molecular chain by substituting some of the acryl with fluorine.

Since fluorine (F) is very good in moisture resistance and heat resistance, when the coating portion 130 is formed by synthesizing with an acrylic resin, which is a main material of the coating portion 130, the fluorine (F) may be wrinkled due to heat or moisture in the device or the like. You can prevent it.

In addition, since fluorine has a property of improving the durability of the compound in combination with other materials, the upper layer having a high concentration of fluorine may have a pencil hardness of 3H or more.

Accordingly, the optical sheet 100 can be prevented from being deformed or flawed due to an external impact or scratch with other components.

In particular, the fluorine series may be representatively magnesium fluoride (MgF ₂ ). Magnesium fluoride is generally used as a coating material for a low reflection film, and may not improve the brightness because it does not pass through the protruding portion 120 again by using a low refractive index.

On the other hand, the coating unit 130 may be formed of a primer (Primer) coating. The primer treatment process may be performed by applying the above-described polymer material on a substrate to be primed, and coating it using a coater device.

In addition, the thickness W of the coating unit 130 may be 10 nm to 5000 nm. If the thickness of the coating unit 130 is 10 nm or more, the optical sheet 100 may improve the light condensing and dispersing effects of the optical sheet 100, thereby improving moisture resistance and durability of the optical sheet 100. When the thickness of the coating unit 130 is 5000 nm or less, the light collecting and dispersing effects of the light may be enhanced in the optical sheet 100 while increasing the moisture resistance and durability of the optical sheet 100.

Referring to FIG. 1E, in the optical sheet 100 according to the exemplary embodiment of the present invention, the hard coating unit 140 may be further disposed below the substrate 110.

The hard coating unit 140 may use a urethane acrylate, but is not limited thereto. Urethane acrylate is easier to synthesize than general materials and easy to control physical properties. In addition, since UV (ultra violet) coating is used as a method of thermosetting urethane acrylate, productivity is high and it is environmentally friendly.

The urethane acrylate may be formed by reacting an isocyanate having an NCO functional group with a polyol having an OH functional group and an acrylate.

The optical sheet 100 may be generated by the heat generated from the light source described later and the overheating caused by the operation of the liquid crystal display when the hard coating 140 made of urethane acrylate is further formed on the lower portion of the substrate 110. Heat deformation can be prevented and durability can be improved.

2A to 2E are views illustrating an optical sheet according to another embodiment of the present invention.

Referring to FIG. 2A, the optical sheet 200 according to another embodiment of the present invention may be located on the substrate 210 and the protrusion 220 positioned on one surface of the substrate 210 and the other surface of the substrate 210. It may include a coating layer 230.

Here, the description of the same parts as in the above-described embodiment will be omitted.

The protrusion 220 may be formed of a transparent polymer resin to transmit light incident from the outside. Here, the polymer resin may be any one selected from the group consisting of acrylic, polycarbonate, polypropylene, polyethylene, and polyethylene terephthalate.

Here, the protrusion 220 may be a micro lens or a lenticular lens, unlike the prism portion of the above-described embodiment.

2A to 2C, the micro lens may be formed to have an embossed hemisphere on one surface of the substrate 210.

The microlens may vary in the degree of diffusion, the degree of refraction, the light condensation, etc. according to the size and the density of the lens. Accordingly, the microlens may have a constant diameter of the lens as shown in FIG. 2B, an irregular diameter of the lens as shown in FIG. 2C, and a constant or irregular height of the lens. .

In addition, the lens diameter of the micro lens may be formed to 20 ㎛ ~ 200 ㎛, 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.

If the microlenses are formed to have an embossed hemispherical surface, as described above, some of the light incident from the outside, for example, from under the microlens, is uniformly refracted at all azimuth angles in the hemispherical surface to produce the microlenses. Permeable.

For this reason, some of the light incident from the lower part of the microlens can be uniformly diffused upward and can be focused.

2D and 2E, the protrusion 220 may be a lenticular lens. The lenticular lens has a semicircular cross-sectional shape and may be continuously formed in the longitudinal direction instead of a pattern shape like the aforementioned micro lens. For example, it may be in the form of a tunnel.

In the lenticular lens, as shown in FIG. 2D, the pitch of the lens may be constant. Alternatively, as shown in FIG. 2E, the pitch of the lens may be irregular, and the height of the lens may also be constant or irregular. It is not limited.

3 is a view showing an optical sheet according to another embodiment of the present invention.

Referring to FIG. 3, an optical sheet 300 according to another embodiment of the present invention is positioned on a substrate 310, a protrusion 320 positioned on one surface of the substrate 310, and the other surface of the substrate 310. It may include a coating layer 330.

Here, the description of the same parts as in the above-described embodiment will be omitted.

The protrusion 320 may be formed of a transparent polymer resin to transmit light incident from the outside. Here, the polymer resin may be any one selected from the group consisting of acrylic, polycarbonate, polypropylene, polyethylene, and polyethylene terephthalate.

In the present embodiment, a prism-shaped protrusion is described as an example, but the above-described micro lens or lenticular lens may be used, but the present invention is not limited thereto.

The protrusion 320 may include a resin 327 and a plurality of beads 328. The resin 327 may be acrylic resin, and the plurality of beads 328 may be any one or more selected from the group consisting of polymethylmethacrylate (PMMA), polystyrene, and silicone.

In addition, the resin 327 may further include an antistatic agent made of polyvinylbenzyl, poly (meth) acrylate, styrene- (meth) acrylate copolymer, methacrylate methacrylimide copolymer, or the like.

Here, the beads 328 with respect to the resin 327 may be included in 1 to 10 parts by weight. In addition, the particle diameters of the beads 328 distributed in the resin 327 may not be uniform and may have an irregular distribution.

The shape of the bead 328 may be a circle, an oval, a snowman, an uneven circle, but is not limited thereto.

In addition, the beads 328 distributed in the resin 327 may have an irregular distribution without having a regular distribution in the resin 327. In this case, the beads 328 distributed in the resin 327 may be completely included so as not to be exposed on the surface of the protrusion 320.

Therefore, the optical sheet according to another embodiment of the present invention may have an effect of diffusing light incident from the light source by including a plurality of beads in the protrusion.

Table 1 shows the results of measuring the moisture content and moisture absorption rate of the optical sheet including the coating layer according to an embodiment of the present invention as a table.

In Table 1 below, the optical sheet on which the coating layer was formed according to the embodiment of the present invention was named as an experimental example, and the optical sheet on which the coating layer was not formed was described as a comparative example.

Here, in the case of the moisture content rate, the characteristics of the optical sheets are different for each manufacturing month, so the moisture content rate of the optical sheet according to the manufacturing month was measured, and the moisture absorption rate is measured regardless of the manufacturing month because it is not affected by the manufacturing month. The average is shown.

Average moisture content of the optical sheet at each measurement date and time (ppm) Average moisture absorption (ppm) June In July August Comparative example 600 900 900 1300 Experimental Example 450 700 700 950

Referring to Table 1, according to an embodiment of the present invention, in the case of the experimental example of the optical sheet on which the coating layer is formed, it can be seen that the moisture content is lowered by 20% or more than the comparative example of the optical sheet on which the coating layer is not formed. Hygroscopicity was also lowered by more than 25%.

4A and 4B are exploded perspective views and cross-sectional views illustrating a configuration of a backlight unit including an optical sheet according to embodiments of the present disclosure.

In FIG. 4A, the edge type backlight unit is illustrated as the backlight unit, and the overlapping description is omitted since the optical sheet of the present invention is the same as the above-described optical sheet.

4A and 4B, the backlight unit 400 according to an exemplary embodiment of the present invention may be provided in the liquid crystal display and may provide light to the liquid crystal panel provided in the liquid crystal display.

The backlight unit 400 may include a light source 420 and an optical sheet 430. In addition, the backlight unit 400 may further include a light guide plate 440, a reflective plate 450, a bottom cover 460, and a mold frame 470.

The light source 420 may generate light by using driving power applied from the outside, and may emit the generated light.

For example, at least one light source 420 may be formed on one side of the light guide plate 440 along the long axis direction of the light guide plate 440, or at least one light source 420 may be formed on each side of the light guide plate 440. . Here, the light emitted from the light source 420 is incident directly into the light guide plate 440, or the light source housing 422 formed to surround a portion of the light source 420, for example, about 3/4 of the outer peripheral surface of the light source 420. After reflection, the light may enter the light guide plate 440.

The light source 420 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 sheet 430 may be disposed on the light guide plate 440. The optical sheet 430 may serve to collect light incident from the light source 420.

The optical sheet 430 may include a substrate, a protrusion disposed on one surface of the substrate, and a coating portion disposed on the other surface of the substrate and including a fluorine acrylate.

Therefore, there is an advantage that can improve the moisture resistance, durability and heat resistance of the optical sheet 430. As a result, it is possible to improve the reliability of the backlight unit 400 according to an embodiment of the present invention.

The light guide plate 440 may be disposed to face the light source 420, and may guide the light so that light incident from the light source 420 is emitted upward.

The reflection plate 450 may be disposed under the light guide plate 440, and may reflect light emitted downward from the light source 420 through the light guide plate 440 upward.

The bottom cover 460 may include a bottom portion 462 and a side portion 464 formed to extend from the bottom portion 462 to form an accommodation space, and the light source 420 and the optical sheet 430 may be formed in the accommodation space. The light guide plate 440 and the reflective plate 450 may be accommodated.

The mold frame 470 may be formed in a substantially rectangular frame shape and may be fastened with the bottom cover 460 from the top of the bottom cover 460 in a top down manner.

5A and 5B are exploded perspective views and cross-sectional views illustrating a configuration of a backlight unit according to an embodiment of the present invention. 5A and 5B illustrate a direct backlight unit as the backlight unit, but the present invention is not limited thereto. Meanwhile, the backlight unit illustrated in FIGS. 5A and 5B is substantially the same as the backlight unit illustrated in FIGS. 4A and 4B except for arrangement of a light source and a change in components thereof, and thus, redundant descriptions thereof will be omitted. Only its features will be described.

5A and 5B, the backlight unit 500 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 500 may include a light source 520 and an optical sheet 530.

In addition, the backlight unit 500 may further include a reflection plate 550, a bottom cover 560, a mold frame 570, and a diffusion plate 580.

At least one light source 520 may be disposed under the diffuser plate 580. For this reason, the light emitted from the light source 520 may be incident directly to the diffuser plate 580.

The optical sheet 530 may be disposed on the diffuser plate 580. The optical sheet 530 may serve to condense the light incident from the light source 520.

The optical sheet 530 may include a substrate, a protrusion disposed on one surface of the substrate, and a coating portion disposed on the other surface of the substrate and including a fluorine acrylate.

Therefore, there is an advantage in that the moisture resistance, durability, and heat resistance of the optical sheet 530 can be improved. As a result, it is possible to improve the reliability of the backlight unit 500 according to an embodiment of the present invention.

The diffusion plate 580 may be disposed between the light source 520 and the optical sheet 530, and may diffuse light incident from the light source 520 upward. This is to prevent the shape of the light source 520 from being visible through the backlight unit 500 and to further diffuse the light.

6A and 6B are exploded perspective views and cross-sectional views for describing the configuration of a liquid crystal display according to an exemplary embodiment of the present invention. 6A and 6B illustrate the backlight unit illustrated in FIGS. 4A and 4B as the backlight unit, but the present invention is not limited thereto. The backlight unit illustrated in FIGS. 5A and 5B may be employed as the backlight unit. Meanwhile, since the backlight units illustrated in FIGS. 6A and 6B are the same as described above, overlapping descriptions are omitted and only the features thereof will be described.

6A and 6B, the liquid crystal display 600 according to an exemplary embodiment may display an image by using the electro-optical characteristics of the liquid crystal. The liquid crystal display 600 may include a backlight unit ( 610 and a liquid crystal panel 710.

The backlight unit 610 may be mounted under the liquid crystal panel 710 and may provide light to the liquid crystal panel 710.

The backlight unit 610 may include a light source 620 and an optical sheet 630.

In addition, the backlight unit 610 may further include a light guide plate 640, a reflective plate 650, a bottom cover 660, and a mold frame 670.

The liquid crystal panel 710 may be seated on the mold frame 670 and may be fixed by the top cover 720 fastened to the bottom cover 660 in a top-down manner.

The liquid crystal panel 710 may display an image using light provided from the backlight unit 610, specifically, light emitted from the light source 620.

The liquid crystal panel 710 may include a color filter substrate 712 and a thin film transistor substrate 714 facing each other with the liquid crystal interposed therebetween.

The color filter substrate 712 may implement colors of the image displayed through the liquid crystal panel 710.

The color filter substrate 712 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 712.

The thin film transistor substrate 714 is electrically connected to the printed circuit board 618 on which a plurality of circuit components are mounted through the driving film 616. The thin film transistor substrate 714 may apply a driving voltage provided from the printed circuit board 618 to the liquid crystal in response to a driving signal provided from the printed circuit board 618.

The thin film transistor substrate 714 may include a thin film transistor and a pixel electrode formed of a thin film on another substrate 714 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 714.

As described above, the optical sheet, the backlight unit including the same, and the liquid crystal display according to the exemplary embodiment of the present invention have an advantage of improving moisture resistance, durability, and heat resistance of the optical sheet.

Therefore, the optical sheet, the backlight unit including the same, and the liquid crystal display according to the exemplary embodiment of the present invention have an advantage of providing a backlight unit and a liquid crystal display having improved reliability.

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 1E illustrate an optical sheet according to an embodiment of the present invention.

2A to 2E illustrate an optical sheet according to another embodiment of the present invention.

3 is a view showing an optical sheet according to another embodiment of the present invention.

4A and 4B are cross-sectional views and perspective views illustrating a backlight unit according to an embodiment of the present invention.

5A and 5B are cross-sectional views and perspective views illustrating a backlight unit according to another embodiment of the present invention.

6A and 6B are cross-sectional views and a perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

Claims (12)

materials; A protrusion located on one surface of the substrate; And Located on the other side of the substrate, the optical sheet comprising a coating comprising a fluorine-based acrylate. The method of claim 1, The coating part is an optical sheet made of a fluorine (F) -containing compound. The method of claim 1, The thickness of the coating is 10 to 5000nm optical sheet. The method of claim 1, The coating part is an optical sheet having a pencil hardness of 3H or more. The method of claim 1, An optical sheet further comprising a hard coating made of urethane acrylate under the substrate. The method of claim 1, The optical sheet further comprises a primer layer between the substrate and the protrusion. The method of claim 1, The other surface of the substrate is an optical sheet opposite to the surface on which the protrusion is located on the substrate. The method of claim 1, The protruding portion is any one selected from the group consisting of a prism portion, a micro lens portion and a lenticular lens portion. The method of claim 1, The protrusion is an optical sheet including a plurality of beads. The method of claim 9, The protrusion further includes a resin, The beads are contained in 1 to 10 parts by weight based on 100 parts by weight of the resin. Light source; And An optical sheet positioned on the light source, The optical sheet is a substrate; A protrusion located on one surface of the substrate; And Located on the other side of the substrate, the backlight unit comprising a coating comprising a fluorine-based acrylate. Light source; An optical sheet positioned on the light source; And A liquid crystal panel positioned on the optical sheet; The optical sheet is a substrate; A protrusion located on one surface of the substrate; And Located on the other side of the substrate, the liquid crystal display comprising a coating comprising a fluorine-based acrylate.

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