KR100989047B1 - Optical Sheet, Back Light Unit And Liquid Crystal Display Device Comprising The Same - Google Patents

Abstract

The present invention includes a substrate and a prism portion positioned on the substrate, the prism portion including a plurality of diffusion particles, wherein the plurality of diffusion particles correspond to a cumulative volume of 50% with respect to a cumulative volume of 100% of the total diffusion particles. An optical sheet having a particle diameter of X μm and a cumulative volume of diffused particles having a particle size in the range of X−1 μm to X + 1 μm is 40 to 70% of the accumulated volume of all the diffused particles.

Optical sheet, backlight unit

Description

Optical Sheet, Back Light Unit And Liquid Crystal Display Device Comprising The Same}

The present invention relates to an optical 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 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.

In the conventional backlight unit having the above configuration, the light emitted from the light source can be diffused through the diffusion sheet and then focused by the prism sheet. The prism sheet may serve to condense the light emitted from the light source to increase the luminance.

However, the light incident on the prism sheet is not excellent in the degree of diffusion, and thus there is a problem in that it is not possible to exhibit better light collection efficiency.

The present invention provides an optical sheet having both a light condensing and diffusing function, a backlight unit and a liquid crystal display including the same.

In order to achieve the above object, the optical sheet according to an embodiment of the present invention is located on the substrate and the substrate, and includes a prism portion including a plurality of diffusion particles, the plurality of diffusion particles of the total diffusion particles The particle size of the diffusion particles corresponding to the cumulative volume 50% of the cumulative volume of 100% of the cumulative volume is X ㎛, the cumulative volume of the diffusion particles having a particle size in the range of X-1 ㎛ to X + 1 ㎛ compared to the cumulative volume of the total 40 to 70%.

In order to achieve the above object, 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 and the substrate, a plurality of diffusion particles And a prism portion including the particles, wherein the plurality of diffusion particles have a particle size of X μm, and X-1 μm to X + 1 μm, of which the cumulative volume corresponds to a cumulative volume of 50% with respect to 100% of the cumulative volume of all the diffused particles. The cumulative volume of the diffused particles having a particle size in the range may be 40 to 70% of the cumulative volume of the entire diffused particles.

In order to achieve the above object, a liquid crystal display according to an 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, the optical sheet is a substrate and Located on the substrate and comprises a prism portion including a plurality of diffusion particles, the plurality of diffusion particles is the particle size of the diffusion particles corresponding to the cumulative volume 50% to 100% of the cumulative volume of the total diffusion particles is X㎛ The cumulative volume of the diffusing particles having a particle size in the range of X-1 μm to X + 1 μm may be 40 to 70% of the cumulative volume of all the diffusing particles.

In order to achieve the above object, the optical sheet according to an embodiment of the present invention includes a substrate, a prism portion positioned on the substrate and a protective layer positioned below the substrate and including a plurality of diffusion particles, The plurality of diffused particles may have a particle size of X μm and a particle size in a range of X-0.5 μm to X + 0.5 μm, with a particle size of 50% of the cumulative volume with respect to 100% of the total volume of the diffused particles. The cumulative volume may be 40 to 70% of the cumulative volume of the entire diffused particles.

In order to achieve the above object, 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 a substrate, a prism portion located on the substrate and the substrate Located in the lower portion, and comprises a protective layer including a plurality of diffusion particles, the plurality of diffusion particles is the particle size of the diffusion particles corresponding to the cumulative volume 50% of the cumulative volume 100% of the total diffusion particles is X㎛, The cumulative volume of the diffusing particles having a particle size in the range of X-0.5 μm to X + 0.5 μm may be 40 to 70% of the cumulative volume of all the diffusing particles.

In order to achieve the above object, the liquid crystal display device according to an 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, the optical sheet is a substrate, And a protective layer positioned on the substrate and a lower portion of the substrate, the protective layer including a plurality of diffusion particles, wherein the plurality of diffusion particles have a cumulative volume of 50% with respect to 100% of the cumulative volume of all the diffusion particles. The particle size of the corresponding diffusion particles is X μm, and the cumulative volume of the diffusing particles having a particle size in the range of X-0.5 μm to X + 0.5 μm may be 40 to 70% of the cumulative volume of all the diffusion particles.

Therefore, the optical sheet, the backlight unit and the liquid crystal display including the same according to the present invention include an optical sheet having both light diffusion and condensing functions, thereby improving the brightness of the light.

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

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

Referring to FIG. 1, an optical sheet 135 according to an embodiment of the present invention is located on a substrate 131, on the substrate 131, and includes a resin 132 and a plurality of diffusion particles 133. It may include a prism portion 134.

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, the substrate 131 is 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 any one, but is not limited thereto.

The prism unit 134 may serve to condense the light incident from the light source.

The prism portion 134 may have a triangular shape in cross section thereof. In addition, the prism portion 134 may be linearly formed along the longitudinal direction of the prism portion 134, but may be formed in a triangular prism rod shape in appearance, but is not limited thereto.

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

Here, the diffusion particles 133 may be included in an amount of 1 to 10 parts by weight based on the resin 132. If the content of the diffusion particles 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 diffuse by the beads, and the diffusion particles (for the resin 132) may be prevented. When the content of 133) is 10 parts by weight or less, there is an advantage in that the transmittance of light incident from the light source is lowered.

In this case, the particle diameters of the plurality of diffusion particles 133 distributed in the resin 132 may not be uniform but may have an irregular distribution.

The plurality of diffusion particles have a particle diameter of X µm and a particle size in the range of X-1 µm to X + 1 µm with respect to 100% of the cumulative volume (cumulative volume) of the total diffusion particles. The cumulative volume of the diffused particles may be 40 to 70% of the cumulative volume of the entire diffused particles.

In order to examine in more detail, with reference to Figure 2 which is a graph showing the cumulative volume according to the particle diameter of all the diffused particles included in the prism portion. Here, the horizontal axis represents the particle diameter (μm) of the diffusion particles, the left vertical axis represents the volume (%) occupied by each diffuse particle, and the right vertical axis represents the cumulative volume (%) of all the diffuse particles.

Referring to FIG. 2, the particle size ranges from X-1 μm to X + 1 μm, centering on the diffusion particles corresponding to the particle size X μm corresponding to the cumulative volume 50% with respect to 100% of the cumulative volume of all the diffused particles. It can be seen that the cumulative volume occupied by the diffuse particles is in the range of about 40 to 70%. Here, the minimum particle diameter of the diffusion particles is 0.5㎛, the maximum particle diameter may be 10㎛, X may be 2 to 3㎛.

Diffusion particles having a particle size of X μm account for about 12% of the total volume of the particles, about 5% of particles having a particle size of X-1 μm, and about 7% of particles having a particle size of X + 1 μm. May occupy the volume.

More specifically, for example, if the total volume of the diffusion particles present in the prism portion is 100%, if the cumulative volume from the diffusion particles having a particle size of 0.5 μm to the diffusion particles having a particle size of 2 μm is 50% , The particle size of the diffusion particles corresponding to 50% of the cumulative volume is 2㎛.

In addition, the cumulative volume of the diffusion particles corresponding to the particle size in the range of X-1 μm to X + 1 μm is 40 to 70% of the diffusion particles having a particle size of 1 to 3 μm when X μm is 2 μm. Cumulative volume is 40 to 70%.

Table 1 shows the results of measuring the diffusion effect and the brightness of the optical sheet according to the cumulative volume of the diffusion particles corresponding to the particle size in the range of 1㎛ 3㎛ when X is 2㎛.

Cumulative volume (%) of diffused particles having a particle size in the range of 1 μm to 3 μm Diffusion effect Luminance 20 × ◎ 30 × ◎ 40 ○ ◎ 50 ○ ○ 60 ○ ○ 70 ◎ ○ 80 ◎ × 90 ◎ ×

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

Referring to Table 1, in an embodiment of the present invention, among the plurality of diffusion particles included in the prism portion, the diffusion particles having a particle size of 2 μm corresponding to a cumulative volume of 50% to a cumulative volume of 100% of the total diffusion particles are centered. As a result, when the cumulative volume occupied by the diffusion particles corresponding to the particle diameter in the range of 1 μm to 3 μm is in the range of about 40 to 70%, it can be seen that the diffusion effect and the luminance are excellent.

That is, when the cumulative volume occupied by the diffusion particles corresponding to the particle size in the range of X-1 μm to X + 1 μm is 40% or more, the diffusion effect of light incident from the light source to the optical sheet may be improved.

In addition, when the cumulative volume occupied by the diffusion particles corresponding to the particle size in the range of X-1 μm to X + 1 μm is 70% or less, the volume of the diffusion particles having the same particle diameter is increased to prevent the luminance from falling. have.

Therefore, by forming diffuser particles having a cumulative volume of 40 to 70% by diffusion particles corresponding to particle diameters in the range of X-1 μm to X + 1 μm, the light incident from the light source can be diffused. There is this.

Meanwhile, the diffusion particles 133 distributed in the resin 132 may be completely included in the prism portion 134 so as not to be exposed on the surface of the prism portion 134.

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 optical sheet. A part of the light incident on the optical sheet collides with the diffusion particles of the prism part to change the path, and the other part of the light passes through the exit surface of the prism part to the liquid crystal panel.

The light whose path is changed by hitting the diffuser is hit by another adjacent diffuser, and the path is changed again, and some of them are propagated to the liquid crystal panel through the exit surface of the prism part, and the path is changed by hitting another diffuser again.

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

As described above, since the light incident on the optical sheet is reflected by a plurality of diffusion particles formed inside the prism portion and diffuses while changing its propagation path, light may be collected to improve luminance.

3A and 3B illustrate an optical sheet according to an embodiment of the present invention.

3A and 3B, the optical sheet 200 according to the exemplary embodiments of the present invention may include a plurality of diffused particles in the prism portion as in the above-described embodiments, and the cumulative volume of all the diffused particles is 100%. The cumulative volume occupied by the diffused particles corresponding to the particle size in the range of X-1 μm to X + 1 μm centered on the diffused particles corresponding to the particle diameter X μm corresponding to the cumulative volume 50% of 40 to 70% of the contrast. Therefore, in the following description of the diffusion particles are omitted.

The optical sheet 200 may include a substrate 231 and a prism portion 234 positioned on the substrate 231 and including a plurality of peaks 235 and a valley 236.

The cross section of the prism portion 234 may have a triangular shape, and the pitch between the peaks 235 of the prism portion 234 may be 20 to 300 μm.

The peaks 235 of the prism portion 234 may have a meandering shape along the longitudinal direction of the prism portion 234, where the average horizontal amplitude of the peaks 235 of the prism portion 234 is 1. To 20 μm.

In addition, the valleys 236 of the prism portion 234 may also be formed in a serpentine shape to the left and right, and the average horizontal amplitude of the valleys 236 of the prism portion 234 may be 1 to 20 μm.

In addition, the height of the peak 235 from the bottom surface of the prism portion 234 may vary randomly or periodically in the longitudinal direction of the prism portion 234. For example, the average height difference of the mountains 235 may be 1 to 20 μm.

Therefore, not only defects such as the acid 235 of the prism portion 234 crushed due to physical contact with other sheets in contact with the upper part of the optical sheet 200 are difficult to be visually easily detected. It may not affect the image quality of the liquid crystal display device.

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

Referring to FIG. 4, the optical sheet 300 according to an embodiment of the present invention may further include a protective layer 340 including a resin 311 and a plurality of second beads under the substrate 331. have. Here, the prism part includes a plurality of diffusion particles and a resin, which is the same as the above-described embodiments, and will not be described below.

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

The resin 341 is transparent, and an acrylic resin having excellent heat resistance and mechanical properties can 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 resin 341, and may be included in an amount of 10 to 50 parts by weight based on the resin 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 one embodiment of the present invention, the size of the second bead 342 may be substantially the same, and the distribution in the resin 341 may be regular. In contrast, the sizes of the second beads 342 are different from each other, and the distribution in the resin 341 may be irregular.

In addition, the first bead and the second bead 342, which are the aforementioned diffusion particles, may use the same material, and may be different from each other.

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

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

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

Referring to FIG. 5, an optical sheet 400 according to another embodiment of the present invention is positioned on a substrate 410, a prism portion 420 located on the substrate 410, and a lower portion of the substrate 410. The protective layer 430 may include a resin 431 and a plurality of diffusion particles 432.

The substrate 410 serves to transmit the light incident from the light source. For this purpose, since the substrate 410 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 unit 410 serves to condense the light incident from the light source. The prism unit 410 is the same as the above-described embodiments, and a description thereof will be omitted.

The protective layer 430 may serve to improve heat resistance of the optical sheet 400. In more detail, the protective layer 430 may include a resin 431 and a plurality of diffusion particles 432 dispersed in the resin 431. Since the basic description of the protective layer 430 has been described above, it will be omitted.

The protective layer 430 may include a resin 431 and a plurality of diffusion particles 432 included in the resin 431.

Herein, the particle diameters of the plurality of diffusion particles 432 distributed in the resin 431 may be irregular and may be irregular.

The plurality of diffusion particles 432 have a particle diameter of X µm and a particle size in a range of X-0.5 µm to X + 0.5 µm with respect to 100% of the cumulative volume of the total diffusion particles. The cumulative volume of the diffusion particles may be 40 to 70% of the total cumulative volume.

In order to examine in more detail, it will be described with reference to Figure 6, which is a graph showing the volume according to the particle diameter of the total diffusion particles contained in the protective layer. Here, the horizontal axis represents the particle diameter (μm) of the diffusion particles, the left vertical axis represents the volume (%) occupied by each diffuse particle, and the right vertical axis represents the cumulative volume (%) of all the diffuse particles.

Referring to FIG. 6, the particle size ranges from X-0.5 μm to X + 0.5 μm with respect to the diffusion particles corresponding to the particle size X μm corresponding to the cumulative volume 50% with respect to the cumulative volume 100% of the total diffusion particles. It can be seen that the cumulative volume occupied by the diffuse particles is in the range of about 40 to 70%. Here, the minimum particle diameter of the diffusion particles is 3㎛, the maximum particle diameter may be 9㎛, X㎛ may be 5 to 7㎛.

Table 2 shows the results of measuring the diffusion effect and luminance of the optical sheet according to the cumulative volume of the diffusion particles corresponding to the particle size in the range of 4.5㎛ 5.5㎛ when X is 5㎛.

Cumulative volume (%) of diffused particles having a particle size in the range of 4.5 μm to 5.5 μm Diffusion effect Luminance 20 × ◎ 30 × ◎ 40 ○ ◎ 50 ○ ○ 60 ○ ○ 70 ◎ ○ 80 ◎ × 90 ◎ ×

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

Referring to Table 2, in an embodiment of the present invention, the diffusion particles having a particle diameter of 5 μm corresponding to a cumulative volume of 50% of the total diffusion particles among the plurality of diffusion particles included in the protective layer are centered. As a result, when the cumulative volume occupied by the diffusion particles corresponding to the particle diameter in the range of 4.5 μm to 5.5 μm is in the range of 40 to 70%, it can be seen that the diffusion effect and the luminance are excellent.

That is, when the cumulative volume occupied by the diffusion particles corresponding to the particle size in the range of X-0.5 μm to X + 0.5 μm is 40% or more, it is possible to improve the diffusion effect of light incident from the light source to the optical sheet.

And, if the cumulative volume occupied by the diffusion particles corresponding to the particle size in the range of X-0.5 ㎛ to X + 0.5 ㎛ is 70% or less, the volume of the diffusion particles having the same particle diameter is increased to prevent the brightness is lowered There is this.

Accordingly, by forming diffuser particles having a cumulative volume of 40 to 70% in the protective layer, which are occupied by diffusion particles corresponding to particle diameters in the range of X-0.5 μm to X + 0.5 μm, the light incident from the light source can be diffused. There is this.

Another embodiment of the present invention has been described with respect to the protective layer, but is not limited to this, it will be appreciated that all of the embodiments related to the prism portion described above are applicable.

In addition, in another embodiment of the present invention has been disclosed to include the diffusion particles in the protective layer, but is not limited to this may include the diffusion particles in the prism portion.

7A and 7B 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. 7A, 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.

7A and 7B, the backlight unit 500 according to an exemplary embodiment of the present invention may be provided in a liquid crystal display and may provide light to a liquid crystal panel provided in the liquid crystal display.

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 light guide plate 540, a reflective plate 550, a bottom cover 560, and a mold frame 570.

The light source 520 may generate light using driving power applied from the outside, and may emit the generated light.

For example, at least one light source 520 may be formed at one side of the light guide plate 540 along the long axis direction of the light guide plate 540, or at least one light source may be formed at each of both sides of the light guide plate 540. . Here, the light emitted from the light source 520 is incident directly into the light guide plate 540, or the light source housing 522 formed to surround a portion of the light source 520, for example, about 3/4 of the outer peripheral surface of the light source 520. After reflection, the light may enter the light guide plate 540.

The light source 520 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 (LED). Light Emitting Diode (LED), but is not limited thereto.

The optical sheet 530 may be disposed on the light guide plate 540. The optical sheet 530 may serve to condense the light incident from the light source 520.

The optical sheet 530 is located on the substrate and the substrate, and includes a prism portion including a plurality of diffusion particles, wherein the plurality of diffusion particles correspond to a cumulative volume of 50% with respect to 100% of the cumulative volume of all the diffusion particles. The particle size of the diffusing particles is X μm, and the cumulative volume of the diffusing particles having a particle size in the range of X−1 μm to X + 1 μm may be 40 to 70% of the cumulative volume of all the diffusing particles.

In addition, the optical sheet 530 includes a substrate, a prism portion positioned on the substrate, and a protective layer positioned below the substrate and including a plurality of diffused particles, wherein the plurality of diffused particles accumulate all of the diffused particles. The particle size of the diffusing particles corresponding to 50% of the cumulative volume is 100 μm and the cumulative volume of the diffusing particles having a particle size in the range of X-0.5 μm to X + 0.5 μm is 40 To 70%.

Therefore, the optical sheet 530 has an advantage of improving the brightness of the light. As a result, display quality of the backlight unit 500 according to an exemplary embodiment may be improved.

The light guide plate 540 may be disposed to face the light source 520, and may guide the light so that light incident from the light source 520 is emitted upward.

The reflective plate 550 may be disposed under the light guide plate 540, and may reflect light emitted downward through the light guide plate 540 among the light emitted from the light source 520.

The bottom cover 560 may include a bottom part 562 and a side part 564 formed to extend from the bottom part 562 to form an accommodation space, and the light source 520 and the optical sheet 530 may be formed in the accommodation space. The light guide plate 540 and the reflective plate 550 may be accommodated.

The mold frame 570 may be formed in a substantially rectangular frame shape and may be fastened to the bottom cover 560 from the top of the bottom cover 560 in a top down manner.

8A and 8B are exploded perspective views and cross-sectional views illustrating a configuration of a backlight unit according to an embodiment of the present invention.

8A and 8B illustrate a direct backlight unit as the backlight unit, but the present invention is not limited thereto. Meanwhile, the backlight unit illustrated in FIGS. 8A and 8B is substantially the same as the backlight unit illustrated in FIGS. 7A and 7B 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.

8A and 8B, 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 sheet 630. In addition, the backlight unit 600 may further include a reflector 650, a bottom cover 660, a mold frame 670, and a diffuser plate 680.

At least one light source 620 may be disposed under the diffuser plate 680. For this reason, the light emitted from the light source 620 may be incident directly to the diffuser plate 680.

The optical sheet 630 may be disposed on the diffuser plate 680. The optical sheet 630 may serve to condense the light incident from the light source 620.

The optical sheet 630 is located on the substrate and the substrate, and includes a prism portion including a plurality of diffusion particles, wherein the plurality of diffusion particles correspond to a cumulative volume of 50% of the cumulative volume of all the diffusion particles. The particle size of the diffusing particles is X μm, and the cumulative volume of the diffusing particles having a particle size in the range of X−1 μm to X + 1 μm may be 40 to 70% of the cumulative volume of all the diffusing particles.

In addition, the optical sheet 630 includes a substrate, a prism portion positioned on the substrate, and a protective layer positioned below the substrate and including a plurality of diffused particles, wherein the plurality of diffused particles accumulate all of the diffused particles. The particle size of the diffusing particles corresponding to 50% of the cumulative volume is 100 μm and the cumulative volume of the diffusing particles having a particle size in the range of X-0.5 μm to X + 0.5 μm is 40 To 70%.

Therefore, the optical sheet 630 has an advantage of improving the brightness of the light. As a result, display quality of the backlight unit 600 according to an exemplary embodiment may be improved.

The diffusion plate 680 may be disposed between the light source 620 and the optical sheet 630, and may diffuse light incident from the light source 620 upward. This is to prevent the shape of the light source 620 from being visible through the backlight unit 600 and to further diffuse the light.

9A and 9B are exploded perspective views and cross-sectional views for describing a configuration of a liquid crystal display according to an exemplary embodiment of the present invention. 9A and 9B illustrate the backlight unit illustrated in FIGS. 7A and 7B as the backlight unit, but the present invention is not limited thereto. The backlight unit illustrated in FIGS. 8A and 8B may be employed as the backlight unit. Meanwhile, since the backlight units shown in FIGS. 9A and 9B are the same as described above, overlapping descriptions are omitted and only the features thereof will be described.

9A and 9B, the liquid crystal display device 900 according to an exemplary embodiment may display an image using the electro-optical characteristics of the liquid crystal.

The LCD 700 may include a backlight unit 710 and a liquid crystal panel 810.

The backlight unit 710 may be mounted under the liquid crystal panel 810 and may provide light to the liquid crystal panel 810.

The backlight unit 710 may include a light source 720 and an optical sheet 730. In addition, the backlight unit 710 may further include a light guide plate 740, a reflective plate 750, a bottom cover 760, and a mold frame 770.

The liquid crystal panel 810 may be seated on the mold frame 770 and may be fixed by the top cover 820 fastened to the bottom cover 760 in a top-down manner.

The liquid crystal panel 810 may display an image using light provided from the backlight unit 710, specifically, light emitted from the light source 720.

The liquid crystal panel 810 may include a color filter substrate 812 and a thin film transistor substrate 814 facing each other with the liquid crystal interposed therebetween.

The color filter substrate 812 may implement a color of an image displayed through the liquid crystal panel 810.

The color filter substrate 812 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, an upper polarizer may be disposed on the color filter substrate 812.

The thin film transistor substrate 814 is electrically connected to the printed circuit board 718 on which a plurality of circuit components are mounted through the driving film 716. The thin film transistor substrate 814 may apply a driving voltage provided from the printed circuit board 718 to the liquid crystal in response to a driving signal provided from the printed circuit board 718.

The thin film transistor substrate 814 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 814.

As described above, the optical 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 diffused particles in the prism portion, which may serve to diffuse and collect light. There is an advantage.

In addition, the backlight unit and the liquid crystal display including the optical sheet according to the embodiments of the present invention have the advantage of preventing the damage caused by the other sheet contacting the upper portion of the prism by bending the shape of the peak and valley of the prism portion. have.

In addition, the optical 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 optical sheet, thereby improving heat resistance and mechanical strength of the optical sheet.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention 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.

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

Figure 2 is a graph showing the volume ratio according to the particle diameter of the diffusion particles with respect to all the diffusion particles contained in the prism portion according to an embodiment of the present invention.

3A and 3B are a perspective view and a plan view of an optical sheet according to an embodiment of the present invention.

4 is a perspective view of an optical sheet according to an embodiment of the present invention.

5 is a cross-sectional view of an optical sheet according to another embodiment of the present invention.

Figure 6 is a graph showing the volume ratio according to the particle diameter of the diffusion particles with respect to the total diffusion particles contained in the protective layer according to an embodiment of the present invention.

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

8A and 8B illustrate a backlight unit according to another embodiment of the present invention.

9A and 9B illustrate a liquid crystal display according to an exemplary embodiment of the present invention.

Claims (23)

materials; And Located on the substrate, comprising a prism portion including a plurality of diffusion particles, The diffusion particles may have a particle diameter of 50 μm and a particle size in the range of X−1 μm to X + 1 μm, with respect to 100% of the cumulative volume of all the diffused particles. The cumulative volume of the optical sheet 40 to 70% of the cumulative volume of the total diffusion particles. The method of claim 1, The minimum particle diameter of the plurality of diffusion particles is 0.5 ㎛ the optical sheet. The method of claim 1, An optical sheet having a maximum particle diameter of the plurality of diffusion particles is 10㎛. The method of claim 1, X is an optical sheet of 2 to 3㎛. The method of claim 1, The plurality of diffusing particles are first beads. The method of claim 1, The plurality of diffusion particles are at least one selected from the group consisting of polymethyl methacrylate (PMMA), polystyrene and silicon. The method of claim 1, The prism portion includes a plurality of acids, The height of the peak is randomly varied along the longitudinal direction of the prism portion. The method of claim 1, The prism portion includes a plurality of acids, The acid twists the left and right along the longitudinal direction of the prism portion. The method of claim 1, An optical sheet further comprising a protective layer comprising a resin and a plurality of second beads on one surface of the substrate. The method of claim 9, The second bead is 10 to 50 parts by weight based on the resin. Light source; And An optical sheet positioned on the light source, The optical sheet includes a substrate and a prism portion positioned on the substrate and including a plurality of diffused particles, wherein the plurality of diffused particles correspond to 50% of the cumulative volume with respect to 100% of the cumulative volume of all the diffused particles. The backlight unit having a particle diameter of X µm and a cumulative volume of the diffusion particles having a particle size in the range of X-1 µm to X + 1 µm is 40 to 70% of the cumulative volume of all the diffusion particles. Light source; An optical sheet positioned on the light source; And It includes a liquid crystal panel positioned on the optical sheet, The optical sheet includes a substrate and a prism portion positioned on the substrate and including a plurality of diffused particles, wherein the plurality of diffused particles correspond to 50% of the cumulative volume with respect to 100% of the cumulative volume of all the diffused particles. The particle size of the liquid crystal display device wherein the cumulative volume of the diffusing particles having a particle size in the range of X-1㎛ to X + 1㎛ 40 to 70% of the cumulative volume of all the diffusion particles. materials; A prism portion positioned on the substrate; And Located under the substrate, comprising a protective layer comprising a plurality of diffusion particles, The plurality of diffused particles may have a particle size of X μm and a particle size in a range of X-0.5 μm to X + 0.5 μm, with a particle size of 50% of the cumulative volume with respect to 100% of the total volume of the diffused particles. The cumulative volume of the optical sheet 40 to 70% of the cumulative volume of the total diffusion particles. The method of claim 13, The minimum particle diameter of the plurality of diffusion particles is 3㎛ the optical sheet. The method of claim 13, The maximum particle diameter of the plurality of diffusion particles is 9㎛ the optical sheet. The method of claim 13, X is 5 to 7㎛ optical sheet. The method of claim 13, The plurality of diffusion particles are second beads. The method of claim 13, The plurality of diffusion particles are at least one selected from the group consisting of polymethyl methacrylate (PMMA), polystyrene and silicon. The method of claim 13, The prism portion includes a plurality of acids, The height of the peak is randomly varied along the longitudinal direction of the prism portion. The method of claim 13, The prism portion includes a plurality of acids, The acid twists the left and right along the longitudinal direction of the prism portion. The method of claim 13, The protective layer further includes a resin, The plurality of diffusion particles are contained in 10 to 50 parts by weight based on the resin. Light source; And An optical sheet positioned on the light source, The optical sheet includes a substrate, a prism portion positioned on the substrate, and a protective layer positioned below the substrate, the protective layer including a plurality of diffusion particles, wherein the plurality of diffusion particles have a cumulative volume of 100% of the total diffusion particles. The particle size of the diffusing particles corresponding to 50% of the cumulative volume is X μm, and the cumulative volume of the diffusing particles having a particle size in the range of X-0.5 μm to X + 0.5 μm is 40 to 70% of the cumulative volume of all the diffuse particles. Backlight unit. Light source; An optical sheet positioned on the light source; And It includes a liquid crystal panel positioned on the optical sheet, The optical sheet includes a substrate, a prism portion positioned on the substrate, and a protective layer positioned below the substrate, the protective layer including a plurality of diffusion particles, wherein the plurality of diffusion particles have a cumulative volume of 100% of the total diffusion particles. The particle size of the diffusing particles corresponding to 50% of the cumulative volume is X μm, and the cumulative volume of the diffusing particles having a particle size in the range of X-0.5 μm to X + 0.5 μm is 40 to 70% of the cumulative volume of all the diffuse particles. LCD display device.

Images