KR100961699B1 - Optical Sheet, Back Light Unit And Liquid Crystal display Device Comprising the same - Google Patents

Abstract

The present invention includes a substrate including a first surface and a second surface facing each other and a prism portion positioned on the substrate, wherein the plurality of acids are 100 to 200 μm in a length direction of the prism portion. The height varies with a period of and the vertical distance H ₁ from one point of the first face of the substrate to the second face is the vertical distance H ₂ from another point of the first face of the substrate to the second face. And different optical sheets.

Prism, optical sheet

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.

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

In addition, the prism sheet is in contact with the protective sheet on the upper portion. When the acid of the prism sheet is in uniform contact with the protective sheet, moisture in the panel cannot escape and a wet-out phenomenon observed as a stain occurs. There is a problem of degrading the quality of an image.

Accordingly, the optical sheet of the present invention, the backlight unit and the liquid crystal display device including the same, provide an optical sheet having a uniform distribution of luminance and capable of improving image display quality, a backlight unit and a liquid crystal display device including the same.

In order to achieve the above object, an optical sheet according to an embodiment of the present invention is a substrate including a first surface and a second surface facing each other and a prism portion located on the substrate, a plurality of acids Wherein the plurality of peaks vary in height in a length of 100 to 200 μm in the longitudinal direction of the prism portion, and a vertical distance H ₁ from any point on the first surface of the substrate to the second surface is It may differ from the vertical distance H ₂ from another point on the first side to the second side.

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, wherein the optical sheet includes a substrate including first and second surfaces facing each other and on the substrate. And a prism portion including a plurality of mountains, the plurality of mountains varying in height in a length direction of 100 to 200 μm in a length direction of the prism portion, and the second mountains from one point of the first surface of the substrate. The vertical distance H ₁ to the face may be different from the vertical distance H ₂ from the other point of the first face of the substrate to the second face.

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 has a first surface and a first surface facing each other. A substrate including two sides and a prism portion located on the substrate, the prism portion including a plurality of acids, the plurality of acids varying in height in a length of 100 to 200 μm in a longitudinal direction of the prism portion, The vertical distance H ₁ from any point on one surface to the second surface may be different from the vertical distance H ₂ from another point on the first surface of the substrate to the second surface.

The optical sheet of the present invention, the backlight unit and the liquid crystal display including the same have an advantage of providing an optical sheet having a uniform distribution of brightness, a backlight unit and a liquid crystal display including the same by improving the diffusion characteristics of the optical sheet. .

In addition, the optical sheet of the present invention, the backlight unit and the liquid crystal display including the same, the optical sheet which can improve the image display quality by preventing the Wet-Out phenomenon occurs, the backlight unit comprising the same; There is an advantage that can provide a liquid crystal display device.

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

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

Referring to FIG. 1A, an optical sheet 100 according to an embodiment of the present invention may include a substrate 110 and a prism portion 120 positioned on the substrate 110.

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 such that at least one of the first and second surfaces 111a and 111b facing each other, for example, the first surface 111a has a curved surface. Here, the entire first surface 111a may be formed to have a curved surface, or a part of the first surface 111a may be formed to have a curved surface except for an edge of the first surface 111a.

The first surface 111a of the substrate 110 may be formed to have a wave shape, for example, so that peaks and valleys may be alternately formed. The pitch of the peaks formed on the first surface 111a of the substrate 110 may be constant.

In addition, the height difference between the hill and the valley formed to be adjacent to each other on the first surface 111a may be constant. In this case, the pitch of the peaks, and the height difference between the peaks and valleys formed to be adjacent to each other should be appropriately selected according to the thickness and size of the substrate 110, the desired luminance uniformity, the light diffusion rate, and the like, and are not limited thereto.

The substrate 110 may be formed such that the first surface 111a of the substrate 110 has a curved surface through any one of a method such as calendering processing, injection processing, and casting molding. It is not limited to this.

The substrate 110 may be formed to have a thin thickness, for example, 50 μm to 250 μm in response to the thinning of the backlight unit. Here, the thickness of the substrate 110 means an average value of the distance from the peak of the first surface 111a to the second surface 111b and the distance from the valley of the first surface 111a to the second surface 111b. can do.

By making the substrate 110 have a thickness of 50 μm or more, the backlight unit can be made as thin as possible without the mechanical properties and the heat resistance of the optical sheet 100 falling. In addition, by making the substrate 110 have a thickness of 250 μm or less, thickness reduction of the backlight unit may be achieved, and mechanical properties and heat resistance of the optical sheet 100 may be maximized.

The prism unit 120 may be located on the substrate 110, and the prism unit 120 may serve to condense or diffuse light incident from the light source.

The prism part 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 prism portion 120 may have a triangular prism shape in cross section thereof. Here, as shown in FIG. 1A, the prism portion 120 includes a plurality of peaks 121 and valleys 122, and the peaks 121 and valleys 122 extend in the longitudinal direction of the prism portion 120. It can be made in the same manner as linear.

Here, the distance P between the peaks 121 of the prism portion 120 may be 20 to 60 μm, and the angle A of the peak 121 may be 70 to 110 °. In addition, the height (H4) of the prism unit 120, which may be the same as the height of the acid (121) (H _4), may be from 10 to 40㎛.

In addition, as shown in FIG. 1C, which is a side view of FIGS. 1B and 1B, the height of the peak 121 of the prism portion 120 may vary continuously from each bottom surface along the longitudinal direction of the prism portion 120.

Here, the period F in which the height of the peak 121 of the prism 120 is variable may be 100 to 200 μm.

In addition, the valleys 122 of the prism portion 120 may form a continuous bend in the longitudinal direction of the prism portion 120, such a bend may be regular or irregular.

On the other hand, as shown in Figure 1d, the peak 121 of the prism portion 120 may have a zigzag shape randomly left and right, the average horizontal amplitude of the peak 121 may be 1 to 20㎛.

In addition, the valleys 122 of the prism unit 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.

Unlike this, as illustrated in FIGS. 1E and 1F, the peaks 121 and the valleys 122 of the prism portion 120 may have a zigzag shape in which left and right are random.

Referring back to FIG. 1A, the prism portion 120 may include a plurality of peaks 121 and valleys 122, and may further include a base 125 below the valleys 122. The base 125 is positioned below the valley 122 in the prism portion 120 and may be integrated with the prism portion 120.

The base portion 125 may be formed of a height (H ₃₎ of 5 to 50% of the height (H ₄₎ of the acid 121 of the prism 120.

Table 1 shows the results of measuring the defects of the optical sheet and the light transmission characteristics according to the height H ₄ of the mountain 121 and the height H ₃ of the base 125.

Height of base at% of mountain Light transmission characteristics Defective One ◎ ○ 3 ◎ ○ 5 ◎ × 10 ○ × 20 ○ × 30 ○ × 40 ○ × 50 ○ × 60 × × 70 × × 80 × ×

                       Light transmission characteristic-×: Poor, ○: Good, ◎: Very good

                              Bad:-○: Bad, ×: Bad

Referring to Table 1, when the height H ₃ of the base 125 is 5% or more of the height H ₄ of the mountain 121, when the shape of the prism 120 is manufactured, the substrate 110 may be formed. If the height H _{3 of the} base 125 is less than or equal to 50% of the height H ₄ of the mountain 121, the base 125 is too thick to transmit the light incident from the light source. There is an advantage that can be prevented from being lowered.

Therefore, the height H ₃ of the base 125 may be 0.1 to 20 μm.

On the other hand, in the optical sheet according to the embodiment of the present invention described above, the vertical distance H ₁ from any point of the first surface 111a of the substrate 110 to the second surface 111b is formed of the substrate 110. It may be different from the vertical distance H ₂ from another point of the first surface 111a to the second surface 111b.

That is, the vertical distance H ₁ from one point of the first surface 111a of the substrate 110 to the second surface 111b is the second surface (from the other point of the first surface 111a of the substrate 110. The vertical distance H ₂ to 111b) may satisfy a relational expression of 0.1 μm ≦ H ₁ -H _{2 |} ≦ 10 μm.

Table 2 shows the results of measuring the diffusion effect and the brightness of the optical sheet according to the relationship between the vertical distance H ₁ and the vertical distance H ₂ .

Value of │H ₁ -H ₂ │ Diffusion effect Luminance 0.05 × ◎ 0.1 ○ ◎ One ○ ◎ 3 ○ ○ 5 ○ ○ 7 ○ ○ 9 ◎ ○ 10 ◎ ○ 15 ◎ ×

                                         ×: Poor, ○: Good, ◎: Very good

Referring to Table 2, if 0.1 µm ≤ H1-H2, a curved surface is formed on one surface of the substrate 110 to diffuse light incident from the light source, and if H1-H2 | There is an advantage that the level difference of the curved surface of the substrate 110 is too large to prevent the luminance from decreasing.

On the other hand, as described above, in the optical sheet according to an embodiment of the present invention, the period F in which the height of the peak 121 of the prism 120 is variable may be 100 to 200 μm.

Table 3 below shows the results of measuring the out-of-fall and non-falling phenomenon of the optical sheet according to the period of the acid 121. In the following experiment, the protective sheet was attached on the prism portion and then experimented.

Acid cycle (㎛) 아웃 -out phenomenon Rain 80 ○ × 90 ○ ○ 100 ◎ ◎ 110 ◎ ◎ 120 ◎ ◎ 150 ◎ ◎ 180 ◎ ◎ 190 ◎ ◎ 200 ◎ ◎ 210 ○ ◎ 220 × ◎ 230 × ◎

                      ×: Severe occurrence, ○: Slightly generated, ◎: Not observed

Here, the rain fall phenomenon is a kind of chop-out phenomenon, in which the portion where the acid of the prism portion contacts the protective sheet on the upper part is observed as dots, so that it appears to rain on the panel.

Referring to Table 3, if the period (F) of the acid 121 of the prism portion 120 is 100㎛ or more, it can be seen that the knock-out phenomenon and non-falling phenomenon is not observed in the panel, the prism portion 120 If it is 200 micrometers or less of the period F of the acid 121 of (), it turns out that a p-out phenomenon and a non-falling phenomenon are not observed in a panel.

2a to 2c are photographs directly showing the panel resulting from the experiment.

Figure 2a, as shown in Table 3, when the period of the acid is 90㎛, it can be seen that the lines appearing as dots in the center of the panel elongated from top to bottom. That is, such a phenomenon is a rain fall phenomenon.

As shown in Table 3, Figure 2b, when the cycle of the acid is 180㎛, it can be seen that the panel is clean without falling rain or fall-out phenomenon.

On the other hand, as shown in Table 3, Figure 2c, it can be seen that when the cycle of the acid is 220㎛, the stain appears in the center of the panel. That is, such a stain is a check-out phenomenon.

As described above, the optical sheet according to an embodiment of the present invention has an advantage of improving the image quality by preventing the wet-out phenomenon and the falling down phenomenon by forming an acid cycle of 100 to 200 μm. .

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

3A and 3B, an optical sheet 200 according to another embodiment of the present invention includes a substrate 210 and a prism portion 220 positioned on the substrate 210, and the prism portion 220 may further include a first resin 227 and a plurality of first beads 228.

The substrate 210 serves to transmit light incident from the light source. To this end, since the substrate 210 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 210 may be formed such that at least one of the first and second surfaces 211a and 211b facing each other, for example, the first surface 211a has a curved surface. Here, the entire first surface 211a may be formed to have a curved surface, or a part of the first surface 211a may be formed to have a curved surface except for an edge of the first surface 211a.

The first surface 211a of the substrate 210 may be formed to have, for example, a wave shape, so that peaks and valleys may be alternately formed. The pitch of the peaks formed on the first surface 211a of the substrate 210 may be constant.

In addition, the height difference between the hill and the valley formed to be adjacent to each other on the first surface 211a may be constant. In this case, the pitch of the peaks, and the height difference between the peaks and valleys formed to be adjacent to each other should be appropriately selected according to the thickness and size of the substrate 210, the desired brightness uniformity, the light diffusion rate, and the like, and are not limited thereto.

The substrate 210 may be formed such that the first surface 211a of the substrate 210 has a curved surface through any one of a method such as calendering, injection processing, and casting molding. It is not limited to this.

The substrate 210 may be formed to have a thin thickness, for example, 50 μm to 250 μm in response to the thinning of the backlight unit.

By having the substrate 210 have a thickness of 50 μm or more, the backlight unit can be made as thin as possible without the mechanical properties and the heat resistance of the optical sheet 200 falling. In addition, by making the substrate 210 have a thickness of 250 μm or less, thickness reduction of the backlight unit may be achieved, and mechanical properties and heat resistance of the optical sheet 200 may be maximized.

Meanwhile, the vertical distance H ₁ from one point of the first face 211a of the substrate 210 to the second face 211b is determined from the second face (from the other point of the first face 211a of the substrate 210). May differ from the vertical distance H ₂ to 211b).

That is, the vertical distance H ₁ from one point of the first face 211a of the substrate 210 to the second face 211b is the second face (from the other point of the first face 211a of the substrate 210). The vertical distance H ₂ to 211b) may satisfy the relational equation of 0.1 μm ≦ H ₁ -H _{2 |} ≦ 10 μm.

Where 0.1 μm ≦ H ₁ If H ₂ │, a curved surface is formed on one surface of the substrate 210 to diffuse the light incident from the light source. If H ₁ -H ₂ ≦ 10 μm, the curved surface of the substrate 210 may be formed. There is an advantage that the step is too large to prevent the luminance from being lowered.

The prism unit 220 may be positioned on the substrate 210, and the prism unit 220 may serve to condense or diffuse light incident from the light source.

The prism unit 220 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 prism portion 220 may have a triangular prism shape in cross section thereof. The prism portion 220 may include a plurality of peaks 221 and valleys 222, and the peaks 221 and valleys 222 may be linearly formed in the same direction as the length direction of the prism portion 220.

In addition, the height of the peak 221 of the prism portion 220 may be continuously changed from each bottom surface along the longitudinal direction of the prism portion 220. Here, the period F in which the height of the peak 221 of the prism portion 220 varies may be 100 to 200 μm.

In addition, the valleys 222 of the prism portion 220 may form a continuous bend in the longitudinal direction of the prism portion 220, such a bend may be regular or irregular.

Meanwhile, the optical sheet 200 according to an embodiment of the present invention may include a first resin 227 and a plurality of first beads 228 in the prism portion 220. The first resin 227 may be acrylic resin, and the first bead 228 may be any one or more selected from the group consisting of polymethylmethacrylate (PMMA), polystyrene, and silicone.

In addition, the first resin 227 may further include an antistatic agent made of polyvinylbenzyl, poly (meth) acrylate, styrene- (meth) acrylate copolymer, methacrylate methacrylimide copolymer, or the like. .

The first bead 228 may be included in an amount of 1 to 10 parts by weight based on the first resin 227.

Table 4 below shows the results of measuring diffusion and luminance characteristics of the optical sheet according to the content of the first bead 228 with respect to the first resin 227 of the prism portion 220.

Content of first bead relative to the first resin (parts by weight) Diffusion characteristics Luminance characteristics 0.1 × ◎ 0.5 × ◎ One ○ ◎ 2 ○ ○ 3 ○ ○ 5 ○ ○ 7 ○ ○ 9 ○ ○ 10 ◎ ○ 12 ◎ × 15 ◎ ×

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

Referring to Table 4, when the content of the first bead 228 is 1 part by weight or more with respect to the first resin 227 of the prism portion 220, there is an advantage that the diffusion characteristic of the light incident from the light source is excellent. If the content of the first bead 228 is 10 parts by weight or less with respect to the one resin 227, there is an advantage that the luminance can be prevented from being lowered.

Meanwhile, the particle diameter of the first bead 228 distributed in the first resin 227 may not be uniform but may have an irregular distribution.

The shape of the first bead 228 may be a circle, an oval, a snowman, an uneven circle, but is not limited thereto.

In addition, the first bead 228 distributed in the first resin 227 may have an irregular distribution without having a regular distribution in the first resin 227. In this case, the first bead 228 distributed in the first resin 227 may be completely included so as not to be exposed on the surface of the prism portion 220.

As described above, the optical sheet 200 according to another embodiment of the present invention includes a plurality of first beads 228 in the prism portion 220, thereby diffusing the light incident from the light source to uniform the distribution of luminance. There is an advantage that one optical sheet can be provided.

4A and 4B are views illustrating an optical sheet according to another embodiment of the present invention.

4A and 4B, the optical sheet 300 according to another embodiment of the present invention includes a substrate 310, a prism portion 320 positioned on the substrate 310, and a lower portion of the substrate 310. It may include a protective layer 340 positioned in.

The substrate 310 serves to transmit the light incident from the light source. To this end, since the substrate 310 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 310 may be formed such that at least one of the first and second surfaces 311a and 311b facing each other, for example, the first surface 311a has a curved surface. Here, the entire first surface 311a may be formed to have a curved surface, or a part of the first surface 311a may be formed to have a curved surface except for an edge of the first surface 311a.

The first surface 311a of the substrate 310 may be formed to have a wave shape, for example, so that peaks and valleys may be alternately formed. The pitch of the peaks formed on the first surface 311a of the substrate 310 may be constant.

In addition, the height difference between the hill and the valley formed to be adjacent to each other on the first surface 311a may be constant. In this case, the pitch of the peaks, and the height difference between the peaks and valleys formed to be adjacent to each other, should be appropriately selected according to the thickness and size of the substrate 310, the desired brightness uniformity, the light diffusion rate, and the like, and are not limited thereto.

The substrate 310 may be formed such that the first surface 311a of the substrate 310 has a curved surface through any one of a method such as calendering, injection processing, and casting molding. It is not limited to this.

The substrate 310 may be formed to have a thin thickness, for example, a thickness of 50 μm to 250 μm in response to the thickness of the backlight unit.

By having the substrate 310 have a thickness of 50 μm or more, the backlight unit can be made as thin as possible without the mechanical properties and the heat resistance of the optical sheet 300 falling. In addition, by making the substrate 310 have a thickness of 250 μm or less, thickness reduction of the backlight unit may be achieved, and mechanical properties and heat resistance of the optical sheet 300 may be maximized.

On the other hand, the vertical distance H ₁ from one point of the first surface 311a of the substrate 310 to the second surface 311b is the second surface (from the other point of the first surface 311a of the substrate 310). And may differ from the vertical distance H ₂ to 311b).

That is, the vertical distance H ₁ from one point of the first surface 311a of the substrate 310 to the second surface 311b is the second surface (from the other point of the first surface 311a of the substrate 310). vertical distance 311b) H ₂ is 0.1㎛ ≤ │H ₁ - may satisfy the relational expression of H ₂ │≤ 10㎛.

Where 0.1 μm ≦ H ₁ If H ₂ │, a curved surface is formed on one surface of the substrate 310 to diffuse the light incident from the light source. If H ₁ -H ₂ │ 10 µm, the curved surface of the substrate 310 may be formed. There is an advantage that the step is too large to prevent the luminance from being lowered.

The prism part 320 may be positioned on the substrate 310, and the prism part 320 may serve to condense or diffuse light incident from the light source.

The prism part 320 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 prism portion 320 may have a triangular prism shape in cross section thereof. The prism portion 320 includes a plurality of peaks 321 and valleys 322, and the peaks 321 and valleys 322 may be linearly formed in the same direction as the length direction of the prism portion 320.

In addition, the height of the peak 321 of the prism portion 320 may vary continuously from each bottom surface along the longitudinal direction of the prism portion 320. Here, the period F in which the height of the peak 321 of the prism portion 320 is variable may be 100 to 200 μm.

In addition, the valleys 322 of the prism portion 320 may form a continuous bend in the longitudinal direction of the prism portion 320, the bend may be regular or irregular.

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 second resin 341 and a plurality of second beads 342 dispersed in the resin 341.

The second resin 341 may use an acrylic resin that is transparent and has excellent heat resistance and mechanical properties, and may be the same as the first resin of the above-described embodiment. In addition, the second resin 341 may further include an antistatic agent made of polyvinylbenzyl, poly (meth) acrylate, styrene- (meth) acrylate copolymer, methacrylate methacrylimide copolymer, or the like. .

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

The size of the second bead 342 may be appropriately selected according to the thickness of the substrate 410, 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 second resin 341 may be regular. In contrast, the sizes of the second beads 342 are different from each other, and the distribution in the second resin 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.

As described above, the protective layer 340 may prevent the optical sheet 300 from being deformed by heat generated from the light source. That is, wrinkles do not occur in the optical sheet by the second 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 300 by an external impact or other physical force.

In addition, the protective layer 340 may diffuse the light incident from the light source due to the second bead 342 to improve the uniformity of the luminance.

5A to 5B 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. 5A, an 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.

5A and 5B, 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 includes a substrate including a first surface and a second surface facing each other and a prism portion positioned on the substrate, wherein the plurality of acids are 100 in the longitudinal direction of the prism portion. The height varies with a period of from 200 μm, and the vertical distance H ₁ from one point of the first face of the substrate to the second face is perpendicular to the second face of the second face of the substrate. It may differ from the distance H ₂ .

Therefore, by including the acid of the prism portion that varies in the period of 100 to 200㎛, there is an advantage that can prevent the occurrence of the knock-out phenomenon.

In addition, the light incident on the optical sheet 430 is diffused by the substrate having a curved surface to have an advantage of making the luminance uniform.

As a result, display quality of the backlight unit 400 according to an exemplary embodiment may be improved.

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.

6A and 6B are exploded perspective views and cross-sectional views for describing the configuration of a backlight unit according to an embodiment of the present invention.

6A and 6B illustrate the direct type backlight unit as the backlight unit, but the present invention is not limited thereto. Meanwhile, since the backlight unit illustrated in FIGS. 6A and 6B is substantially the same as the backlight unit illustrated in FIGS. 5A and 5B except for the arrangement of light sources and a change in components thereof, the overlapping description is omitted. Only its features will be described.

6A and 6B, 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 includes a substrate including a first surface and a second surface facing each other and a prism portion positioned on the substrate, the prism portion including a plurality of acids, wherein the plurality of acids are 100 in the longitudinal direction of the prism portion. The height varies with a period of from 200 μm, and the vertical distance H ₁ from one point of the first face of the substrate to the second face is perpendicular from the other point of the first face of the substrate to the second face. It may differ from the distance H ₂ .

Therefore, by including the acid of the prism portion that varies in the period of 100 to 200㎛, there is an advantage that can prevent the occurrence of the knock-out phenomenon.

In addition, the light incident on the optical sheet 530 has the advantage of being diffused by the substrate having a curved surface to make the luminance uniform.

As a result, display quality of the backlight unit 500 according to an exemplary embodiment may be improved.

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.

7A and 7B are exploded perspective views and cross-sectional views illustrating a structure of a liquid crystal display according to an exemplary embodiment of the present invention. 7A and 7B illustrate the backlight unit illustrated in FIGS. 5A and 5B as the backlight unit, but the present invention is not limited thereto, and the backlight unit illustrated in FIGS. 6A and 6B may be employed as the backlight unit. Meanwhile, since the backlight unit illustrated in FIGS. 7A and 7B is the same as described above, overlapping descriptions are omitted and only the features thereof will be described.

7A and 7B, 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 device 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 include an optical sheet including an acid of a prism portion that varies in a period of 100 to 200 μm, thereby allowing the panel to be checked out. There is an advantage that can prevent the occurrence of the phenomenon.

In addition, there is an advantage that the luminance can be made uniform by forming a substrate having a curved surface.

Therefore, an optical sheet, a backlight unit, and a liquid crystal display device including the same according to an embodiment of the present invention have an advantage of providing a backlight unit and a liquid crystal display device having a uniform distribution of luminance and improved display quality.

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

2A to 2C are photographs of the panel according to the period of the acid of the optical sheet according to an embodiment of the present invention.

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

4A to 4B illustrate an optical sheet according to another embodiment of the present invention.

5A to 5B are diagrams illustrating a backlight unit according to an embodiment of the present invention.

6A to 6B are diagrams illustrating a backlight unit according to another embodiment of the present invention.

7A to 7B illustrate a liquid crystal display according to an exemplary embodiment of the present invention.

Claims (14)

A first surface and a second surface facing each other, wherein the first surface and the second surface are formed in a wave shape in which peaks and valleys are alternately formed; And Located on the substrate, including a prism portion including a plurality of acids, The plurality of acids are changed in height in a period of 100 to 200㎛ in the longitudinal direction of the prism portion, The vertical distance H ₁ from any point of the first face of the substrate to the second face is different from the vertical distance H ₂ from another point of the first face of the substrate to the second face, An optical sheet of which the height difference between the peaks of the base and the valleys of the base is smaller than the height difference between the peaks of the prism portion and the valleys of the prism portion. The method of claim 1, At least one of the first surface and the second surface of the substrate has a curved surface. delete The method of claim 1, And the vertical distance H ₁ and the vertical distance H ₂ satisfy an expression of 0.1 μm ≦ H ₁ -H _{2 |} ≦ ₁₀ μm. The method of claim 1, The prism portion includes a plurality of first beads. The method of claim 5, The prism portion includes a first resin, The first bead is contained in an amount of 1 to 10 parts by weight based on 100 parts by weight of the first resin. The method of claim 1, At least one of the peaks of the prism portion and the valleys of the prism portion is an optical sheet twisted side to side. The method of claim 1, The height of the valley of the prism portion is variable in the longitudinal direction of the prism portion. The method of claim 1, An optical sheet further comprising a base portion under the valley of the prism portion. The method of claim 9, And the height of the base is 5 to 50% of the height of the peaks of the prism. The method of claim 1, An optical sheet further comprising a protective layer on the lower surface of the substrate. The method of claim 11, The protective layer includes a second resin and a plurality of second beads, The optical sheet of 10 to 50 parts by weight based on 100 parts by weight of the second resin. Light source; And An optical sheet positioned on the light source, The optical sheet includes a first surface and a second surface facing each other, wherein the first surface and the second surface are positioned on the substrate and the substrate having a wave shape in which peaks and valleys are alternately formed, A prism portion including an acid, wherein the plurality of mountains vary in height in a length of 100 to 200 μm in a longitudinal direction of the prism portion, and a vertical distance H from any point of the first surface of the substrate to the second surface ₁ is different from the vertical distance H ₂ from another point of the first surface of the substrate to the second surface, and the height difference between the peak of the base and the valley of the substrate is greater than the height difference of the peak of the prism portion and the valley of the prism portion. Small backlight unit. Light source; An optical sheet positioned on the light source; And A liquid crystal panel positioned on the optical sheet; The optical sheet includes a first surface and a second surface facing each other, wherein the first surface and the second surface are positioned on the substrate and the substrate having a wave shape in which peaks and valleys are alternately formed, A prism portion including an acid, wherein the plurality of mountains vary in height in a length of 100 to 200 μm in a longitudinal direction of the prism portion, and a vertical distance H from any point of the first surface of the substrate to the second surface ₁ is different from the vertical distance H ₂ from another point of the first surface of the substrate to the second surface, and the height difference between the peak of the base and the valley of the substrate is greater than the height difference of the peak of the prism portion and the valley of the prism portion. Small liquid crystal display.

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