KR100916305B1 - Prism Sheet, Back Light Unit And Liquid Crystal Display Device Comprising The Same - Google Patents

Abstract

The present invention provides a substrate, a prism pattern including a resin and a plurality of first beads and a first prism sheet included in an amount of 1 to 10 parts by weight based on the resin.

Prism Sheet, Backlight Unit

Description

Prism Sheet, Backlight Unit And Liquid Crystal Display Device Comprising The Same {Prism Sheet, Back Light Unit And Liquid Crystal Display Device Comprising The Same}

The present invention relates to a prism sheet, a backlight unit including the same, and a liquid crystal display device.

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 be configured of a light source and an optical film to provide light to the liquid crystal panel. Here, the optical film may include a diffusion sheet, a prism sheet or a protective sheet.

In the conventional backlight unit having the above configuration, the light emitted from the light source may be diffused through the diffusion sheet and then collected by the prism sheet.

As described above, since diffusion and condensation of the light emitted from the light source are made by a diffusion sheet, a prism sheet, and the like, which are separately manufactured, there are many limitations in achieving reduction in manufacturing cost and light weight of the backlight unit.

The present invention provides a prism sheet having both light condensing and diffusing functions, a backlight unit including the same, and a liquid crystal display device.

In order to achieve the above object, the prism sheet according to an embodiment of the present invention is located on the substrate, the substrate, the prism pattern comprising a resin and a plurality of first beads and the first bead with respect to the resin It may be included in 1 to 10 parts by weight.

In order to achieve the above object, the backlight unit according to an embodiment of the present invention includes a light source and a prism sheet positioned on the light source, wherein the prism sheet is located on the substrate, the substrate and is formed of a resin and a plurality of agents. A prism pattern including one bead may be included, and the first bead may be included in an amount of 1 to 10 parts by weight based on the resin.

In order to achieve the above object, a liquid crystal display device according to an embodiment of the present invention includes a light source, a prism sheet positioned on the light source and a liquid crystal panel positioned on the prism sheet, the prism sheet is a substrate, A prism pattern is disposed on the substrate and includes a resin and a plurality of first beads, wherein the first beads may be included in an amount of 1 to 10 parts by weight based on the resin.

In order to achieve the above object, a prism sheet according to an embodiment of the present invention is located on the substrate, the substrate, the prism pattern comprising a resin and a plurality of first beads and the refractive index of the first beads and the resin The difference can be 0.01 to 0.5.

In order to achieve the above object, the backlight unit according to an embodiment of the present invention includes a light source and a prism sheet positioned on the light source, wherein the prism sheet is located on the substrate, the substrate and is formed of a resin and a plurality of agents. Including a prism pattern including one bead, the refractive index difference between the first bead and the resin may be 0.01 to 0.5.

In order to achieve the above object, a liquid crystal display device according to an embodiment of the present invention includes a light source, a prism sheet positioned on the light source and a liquid crystal panel positioned on the prism sheet, the prism sheet is a substrate, A prism pattern is disposed on the substrate and includes a resin and a plurality of first beads, and a difference in refractive index between the first beads and the resin may be 0.01 to 0.5.

Therefore, the prism sheet of the present invention, the backlight unit and the liquid crystal display including the same include the prism sheet having both light diffusion and condensing functions, and thus, there is an advantage in that the brightness of light can be improved without a separate optical film.

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

1 is a cross-sectional view of a prism sheet according to an embodiment of the present invention.

Referring to FIG. 1, a prism sheet 135 according to an embodiment of the present invention may include a prism pattern 134 including a substrate 131, a resin 132, and a plurality of first beads 133. have.

The substrate 131 serves to transmit light incident from the light source. To this end, since the substrate 131 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 prism pattern 134 may serve to condense the light incident from the light source.

The prism pattern 134 may have a triangular shape in cross section thereof. In addition, the prism pattern 134 may be formed linearly along the length direction of the prism pattern 134, and thus may be formed in a triangular prism bar shape in appearance, but is not limited thereto.

The prism pattern 134 may include a resin 132 and a plurality of first beads 133. The resin 132 may be acrylic resin, and the first bead 133 may be any one or more selected from the group consisting of polymethyl methacrylate (PMMA), polystyrene, and silicone.

Here, the first bead 133 may be included in an amount of 1 to 10 parts by weight with respect to the resin 132. If the content of the first bead 133 is 1 part by weight or more with respect to the resin 132, it is possible to prevent a problem that light incident from the light source is difficult to be diffused by the beads, and the first with respect to the resin 132. When the content of the bead 133 is 10 parts by weight or less, there is an advantage that the transmittance of light incident from the light source may be lowered.

In this case, the particle diameter of the first bead 133 distributed in the resin 132 may have a uniform and irregular distribution.

In addition, the first beads 133 distributed in the resin 132 may have an irregular distribution without having a regular distribution in the resin 132.

In this case, the first bead 133 distributed in the resin 132 may be completely included in the prism pattern 134 so as not to be exposed on the surface of the prism pattern 134.

Unlike the above-described embodiment, in another embodiment of the present invention, the first bead 133 included in the prism pattern may have a refractive index difference of 0.01 to 0.5 with respect to the resin 132.

Here, when the refractive index of the first bead 133 has a difference of 0.01 or more with respect to the resin 132, light is diffused due to the difference in refractive index between the first bead 133 and the resin 132, thereby improving diffusion characteristics of the prism sheet. When the refractive index of the first bead 133 has a difference of 0.5 or less with respect to the resin 132, the difference between the refractive indices of the first bead 133 and the resin 132 becomes too large, and thus the light may be increased. There is an advantage that can be prevented from reducing the amount going in the liquid crystal panel direction.

That is, according to another embodiment of the present invention, by providing a prism sheet including a first bead 133 having a refractive index difference of 0.01 to 0.5 with respect to the resin 132, the light incident from the light guide plate is the resin 132 The light incident through the first bead 133 and the resin 132 is diffused at an angle according to the difference in refractive index. Accordingly, the light diffused through the first bead 133 is further diffused while passing through the resin 132, so that haze of light may be improved and a viewing angle may be improved.

Therefore, the backlight unit including the prism sheet according to the embodiments of the present invention operates as follows.

Light generated from the light source is incident on the prism sheet. Some of the light incident on the prism sheet hits the bead of the prism pattern to change the path, and the other part of the light proceeds to the liquid crystal panel through the exit surface of the prism pattern.

The light that has changed its path by hitting the bead strikes another adjacent bead and changes its path again, and some of them proceed to the liquid crystal panel through the exit surface of the prism pattern, and some of the light hits another bead to change the path again.

Finally, the light passing through the exit surface of the prism pattern is incident evenly onto the liquid crystal panel.

As described above, since the light incident on the prism sheet is reflected by a plurality of beads formed inside the prism pattern and diffused while changing its propagation path, the light may be collected to improve brightness, as well as to diffuse the plate. Can also perform the function of.

2A and 2B schematically illustrate a prism sheet according to another embodiment of the present invention.

2A and 2B, a prism sheet according to still another embodiment of the present invention may include a plurality of first beads and resins in a prism pattern in the same manner as in the above-described embodiments. Therefore, the description of the plurality of first beads and the resin will be omitted below.

The prism patterns 234 are positioned side by side on the substrate 231, and the peaks 235 and the valleys 236 may be in continuous bend. The cross section of the prism pattern 234 may have a triangular shape, and the pitch between the peaks 235 of the prism pattern 234 may be 20 to 300 μm.

The peaks 235 of the prism pattern 234 may have a random zigzag shape, and the average horizontal amplitude of the peaks 235 of the prism pattern 234 may be 1 to 20 μm.

In addition, the valleys 236 of the prism pattern 234 may also have a random zigzag shape, and the average horizontal amplitude of the valleys 236 of the prism pattern 234 may be 1 to 20 μm.

In addition, the height of the peak 235 from the bottom surface of the prism pattern 234 may change periodically. For example, the average height difference of the mountains 235 may be 1 to 20 μm.

As described above, the horizontal amplitude of the peak 235 of the prism pattern 234 of the prism sheet 200 may be changed randomly, and the height of the peak 235 may be changed periodically. Therefore, not only defects such as the acid 235 of the prism pattern 234 crushed due to physical contact with other sheets in contact with the upper surface of the prism sheet 200 are difficult to be visually easily detected. It may not affect the image quality of the liquid crystal display device.

3 is a cross-sectional view of a prism sheet according to another embodiment of the present invention.

Referring to FIG. 3, the prism sheet 300 according to another exemplary embodiment may further include a protective layer 340 including a plurality of second beads under the substrate 331. Here, the prism pattern includes a plurality of first beads and resins, which are the same as the above-described embodiments, and a description thereof will be omitted below.

The protective layer 340 may serve to improve heat resistance of the prism sheet 300. In more detail, the protective layer 340 may include a resin-based base material 341 and a plurality of second beads 342 dispersed in the base material 341.

The base material 341 is transparent, and an acrylic resin having excellent heat resistance and mechanical properties may be used. The acrylic resin may be, for example, polyacrylate or polymethyl methacrylate.

The second bead 342 may be manufactured using the same or different types of resins as the base material 341, and may be included in an amount of 10 to 50 parts by weight based on the base material 341.

The size of the second bead 342 may be appropriately selected according to the thickness of the substrate 331, and may be 2 to 10 μm.

In another embodiment of the present invention, the size of the second bead 342 may be substantially the same, and the distribution in the base material 341 may be regular. In contrast, the sizes of the second beads 342 are different from each other, and the distribution in the base material 341 may be irregular.

In addition, the first bead and the second bead 342 may use the same material as each other, and may be different from each other.

The protective layer 340 may prevent the prism sheet from being deformed by heat generated from the light source. That is, wrinkles do not form in the prism sheet by the heat resistant base material 341, and even when the prism sheet is deformed at a high temperature, the restoring force of returning to the original prism sheet shape again at room temperature is excellent.

In addition, the protective layer 340 may also serve to prevent scratches on the prism sheet due to external impact or other physical force.

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

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

4A and 4B, the backlight unit 700 according to an exemplary embodiment may be provided in a liquid crystal display and may provide light to the liquid crystal panel provided in the liquid crystal display.

The backlight unit 700 may include a light source 720 and a prism sheet 730. In addition, the backlight unit 700 may further include a light guide plate 740, a reflective plate 750, a bottom cover 760, and a mold frame 770.

The light source 720 may generate light by using driving power applied from the outside, and may emit the generated light.

For example, at least one light source 720 may be formed on one side of the light guide plate 740 along the long axis direction of the light guide plate 740, or at least one light source may be formed on each side of the light guide plate 740. . Here, the light emitted from the light source 720 is incident directly into the light guide plate 740, or the light source housing 722 formed to cover a portion of the light source 720, for example, about 3/4 of the outer peripheral surface of the light source 720 After reflection, the light guide plate 740 may be incident into the light guide plate 740.

The light source 720 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 prism sheet 730 may be disposed on the light guide plate 740. The prism sheet 730 may serve to condense the light incident from the light source 720.

The prism sheet 730 is positioned on the substrate, the prism pattern including the resin and the plurality of first beads and the first bead may include 1 to 10 parts by weight with respect to the resin. The substrate, a prism pattern including a resin and a plurality of first beads and a first bead positioned on the substrate, may have a refractive index difference of 0.01 to 0.5 with respect to the resin.

Therefore, the prism sheet 730 has an advantage of improving the brightness of the light even without additional optical sheets.

As a result, display quality of the backlight unit 700 according to an exemplary embodiment may be improved.

The light guide plate 740 may be disposed to face the light source 720, and may guide the light so that light incident from the light source 720 is emitted upward.

The reflective plate 750 may be disposed under the light guide plate 740, and may reflect light emitted downward from the light source 720 through the light guide plate 740 upward.

The bottom cover 760 may include a bottom portion 762 and a side portion 764 formed to extend from the bottom portion 762 to form an accommodation space, and the light source 720 and the prism sheet 730 may be formed in the accommodation space. The light guide plate 740 and the reflective plate 750 may be accommodated.

The mold frame 770 may be formed in a substantially rectangular frame shape and may be fastened to the bottom cover 760 from the top of the bottom cover 760 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.

All. 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 800 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 800 may include a light source 820 and an optical sheet 830. In addition, the backlight unit 800 may further include a reflector 850, a bottom cover 860, a mold frame 870, and a diffuser plate 880.

At least one light source 820 may be disposed under the diffuser plate 880. For this reason, the light emitted from the light source 820 may be incident directly to the diffusion plate 880.

The prism sheet 830 may be disposed on the diffuser plate 880. The prism sheet 830 may serve to collect light incident from the light source 820.

The prism sheet 830 is positioned on the substrate, the prism pattern including the resin and the plurality of first beads and the first bead may include 1 to 10 parts by weight with respect to the resin. The substrate, a prism pattern including a resin and a plurality of first beads and a first bead positioned on the substrate, may have a refractive index difference of 0.01 to 0.5 with respect to the resin.

Therefore, the prism sheet 830 has an advantage of improving the brightness of the light even without additional optical sheets.

As a result, display quality of the backlight unit 800 according to an exemplary embodiment may be improved.

The diffusion plate 880 may be disposed between the light source 820 and the prism sheet 830, and may diffuse light incident from the light source 820 upward. This is to prevent the shape of the light source 820 from being visible through the backlight unit 800 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 900 according to an exemplary embodiment may display an image by using the electro-optical characteristics of the liquid crystal.

The liquid crystal display device 900 may include a backlight unit 910 and a liquid crystal panel 1010.

The backlight unit 910 may be mounted under the liquid crystal panel 1010 and may provide light to the liquid crystal panel 1010.

The backlight unit 910 may include a light source 920 and a prism sheet 930. In addition, the backlight unit 910 may further include a light guide plate 940, a reflector 950, a bottom cover 960, and a mold frame 970.

The liquid crystal panel 1010 may be seated on the mold frame 970 and may be fixed by the top cover 1020 fastened to the bottom cover 960 in a top-down manner.

The liquid crystal panel 1010 may display an image using light provided from the backlight unit 910, specifically, light emitted from the light source 920.

The liquid crystal panel 1010 may include a color filter substrate 1012 and a thin film transistor substrate 1014 that face each other with the liquid crystal interposed therebetween.

The color filter substrate 1012 may implement colors of an image displayed through the liquid crystal panel 1010.

The color filter substrate 1012 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 1012.

The thin film transistor substrate 1014 is electrically connected to a printed circuit board 918 on which a plurality of circuit components are mounted through the driving film 916. The thin film transistor substrate 1014 may apply a driving voltage provided from the printed circuit board 918 to the liquid crystal in response to a driving signal provided from the printed circuit board 918.

The thin film transistor substrate 1014 may include a thin film transistor and a pixel electrode formed of a thin film on another substrate 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 1014.

As described above, the prism sheet, the backlight unit including the same, and the liquid crystal display according to the exemplary embodiments of the present invention include a plurality of beads in the prism pattern, thereby condensing light and also spreading light. There is an advantage to this.

In addition, the backlight unit and the liquid crystal display including the prism sheet according to the embodiments of the present invention may be bent in the shape of the peaks and valleys of the prism pattern to prevent damage by other sheets in contact with the top of the prism pattern. There is this.

In addition, the prism sheet, the backlight unit including the same, and the liquid crystal display according to the exemplary embodiments of the present invention further include a protective layer under the prism sheet, thereby improving the heat resistance and mechanical strength of the prism sheet.

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 represented by the claims to be described later rather than the 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.

1 is a cross-sectional view of a prism sheet according to an embodiment of the present invention.

2A and 2B are a perspective view and a plan view of a prism sheet according to another embodiment of the present invention.

3 is a perspective view of a prism sheet according to another embodiment of the present invention.

4A and 4B illustrate a backlight unit according to an embodiment of the present invention.

5A and 5B illustrate a backlight unit according to another embodiment of the present invention.

6A and 6B illustrate a liquid crystal display according to an exemplary embodiment of the present invention.

Claims (18)

materials; A prism pattern positioned on the substrate, the prism pattern comprising a resin and a plurality of first beads; And The first bead is included in an amount of 1 to 10 parts by weight based on the resin, The prism pattern includes a peak and a valley, and the height of the peak varies randomly along the longitudinal direction of the prism pattern. The method of claim 1, The first bead is a prism sheet of any one or more selected from the group consisting of polymethyl methacrylate (PMMA), polystyrene and silicone. delete The method of claim 1, A prism sheet further comprising a protective layer on one surface of the substrate. The method of claim 4, wherein The protective layer is a prism sheet including a base material and a plurality of second beads. The method of claim 5, The second bead is included in the prism sheet of 10 to 50 parts by weight based on the base material. Light source; And A prism sheet positioned on the light source, The prism sheet comprises a substrate, a prism pattern positioned on the substrate and comprising a resin and a plurality of first beads, The first bead is included in an amount of 1 to 10 parts by weight based on the resin, The prism pattern includes a peak and a valley, and the height of the peak varies randomly along the longitudinal direction of the prism pattern. Light source; A prism sheet positioned on the light source; And It includes a liquid crystal panel positioned on the prism sheet, The prism sheet comprises a substrate, a prism pattern positioned on the substrate and comprising a resin and a plurality of first beads, The first bead is included in an amount of 1 to 10 parts by weight based on the resin, The prism pattern includes a peak and a valley, and the height of the peak varies randomly along the length direction of the prism pattern. materials; A prism pattern positioned on the substrate, the prism pattern comprising a resin and a plurality of first beads; And The first bead has a refractive index difference of 0.01 to 0.5 with respect to the resin, The prism pattern includes a peak and a valley, and the height of the peak varies randomly along the longitudinal direction of the prism pattern. The method of claim 9, The first bead is a prism sheet selected from the group consisting of polymethyl methacrylate (PMMA), polystyrene and silicone. delete The method of claim 9, A prism sheet further comprising a protective layer on one surface of the substrate. The method of claim 12, The protective layer is a prism sheet including a base material and a plurality of second beads. The method of claim 13, The second bead is included in the prism sheet of 10 to 50 parts by weight based on the base material. Light source; And A prism sheet positioned on the light source, The prism sheet comprises a substrate, a prism pattern positioned on the substrate and comprising a resin and a plurality of first beads, The first bead has a refractive index difference of 0.01 to 0.5 with respect to the resin, The prism pattern includes a peak and a valley, and the height of the peak varies randomly along the longitudinal direction of the prism pattern. Light source; A prism sheet positioned on the light source; And It includes a liquid crystal panel positioned on the prism sheet, The prism sheet comprises a substrate, a prism pattern positioned on the substrate and comprising a resin and a plurality of first beads, The first bead has a refractive index difference of 0.01 to 0.5 with respect to the resin, The prism pattern includes a peak and a valley, and the height of the peak varies randomly along the length direction of the prism pattern. The method of claim 1, The prism sheet of 1-20 micrometers in average height difference of the mountain which varies randomly according to the longitudinal direction of the prism pattern. The method of claim 9, The prism sheet of 1-20 micrometers in average height difference of the mountain which varies randomly according to the longitudinal direction of the prism pattern.

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