KR20090011286A - Optical sheet, backlight unit having the optical sheet and liquid crystal display having the optical sheet - Google Patents

Abstract

An optical sheet, a backlight unit including the same, and a liquid crystal display including the same are provided to reduce a manufacturing cost and a size thereof by simplifying an assembling process thereof. An optical sheet includes a base material(132), a light collection pattern(134), a light diffusion layer(136), and a low refractive index layer(138). The base material is used for transmitting incident light from the outside. The light collection pattern is formed on an upper part of the base material in order to collect the incident light from the outside. The light diffusion layer is formed at a lower part of the base material and diffuses the incident light from the outside. The low refractive index layer is formed between the base material and the light diffusion layer.

Description

Optical sheet, a backlight unit having the same, and a liquid crystal display having the same {OPTICAL SHEET, BACKLIGHT UNIT HAVING THE OPTICAL SHEET AND LIQUID CRYSTAL DISPLAY HAVING THE OPTICAL SHEET}

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

A liquid crystal display (LCD), which is classified as a light receiving display device, includes a backlight unit mounted below a liquid crystal panel displaying an image.

The backlight unit according to the background art is composed of a light source, an optical sheet, a bottom cover, a mold frame, and the like, and is assembled through manual operation by an operator to form a module.

In the backlight unit according to the background art having the above-described configuration, the optical sheet includes, in particular, a diffusion sheet, a prism sheet, a protective sheet, and the like, which are stacked in order during the assembly process of the backlight unit. The diffusion sheet diffuses light incident from a light source, the prism sheet collects light diffused through the diffusion sheet, and the protective sheet serves to protect the prism sheet.

However, since each of the diffusion sheet, the prism sheet, and the protective sheet is manufactured through a separate manufacturing process according to its function, cost reduction and thinning of each of the backlight unit and the liquid crystal display device having the optical sheet may occur. .

Accordingly, an object of the present invention is to provide an optical sheet capable of condensing and diffusing light through a sheet, a backlight unit having the same, and a liquid crystal display having the same.

In addition, another object of the present invention is to provide an optical sheet capable of achieving cost reduction and thinning, a backlight unit having the same, and a liquid crystal display having the same.

Further objects to be solved by the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description. Could be.

Optical sheet according to an embodiment of the present invention for achieving the object to be solved is a substrate for transmitting the light incident from the outside; A condensing pattern formed on the substrate and condensing light incident from the outside; A light diffusion layer formed under the substrate and diffusing light incident from the outside; And a low refractive index layer formed between the substrate and the light diffusion layer.

On the other hand, the backlight unit according to an embodiment of the present invention for achieving the problem to be solved is a light source for emitting light; And an optical sheet for collecting and diffusing light incident from the light source, the optical sheet comprising: a substrate transmitting light incident from the light source; A condensing pattern formed on the substrate and condensing light incident from the light source; A light diffusion layer formed under the substrate and diffusing light incident from the light source; And a low refractive index layer formed between the substrate and the light diffusion layer.

On the other hand, the liquid crystal display device according to an embodiment of the present invention for achieving the problem to be solved is a light source for emitting light; An optical sheet for collecting and diffusing light incident from the light source; And a liquid crystal panel displaying an image using light emitted from the light source, wherein the optical sheet comprises: a substrate transmitting light incident from the light source; A condensing pattern formed on the substrate and condensing light incident from the light source; A light diffusion layer formed under the substrate and diffusing light incident from the light source; And a low refractive index layer formed between the substrate and the light diffusion layer.

Specific details of other embodiments are included in the detailed description and the drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings.

According to the present invention, light can be focused and diffused through one sheet of optical sheet. As a result, cost reduction and thinning of the backlight unit and the liquid crystal display including the optical sheet may be achieved. In addition, since the assembly process of the backlight unit and the liquid crystal display device can be simplified, productivity of the backlight unit and the liquid crystal display device can be improved.

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

Like reference numerals refer to like elements throughout. In addition, when describing the arrangement relationship between the components throughout the specification, when it is disposed on the top, this includes not only the case in which it is arranged in the upper direction in the vertical direction, but also the case in which it is arranged in the oblique direction. Similarly, when describing the arrangement relationship between the components throughout the specification, when disposed below, this includes not only the case disposed below the vertical direction but also the case disposed below the oblique direction.

1 is a perspective view illustrating an optical sheet according to an embodiment of the present invention. 2 is a cross-sectional view for describing in detail the optical sheet shown in FIG. 1.

1 and 2, an optical sheet 130 according to an embodiment of the present invention may be provided in a backlight unit of a liquid crystal display.

The optical sheet 130 may diffuse and collect light incident from an external light source, and the substrate 132, the light collecting pattern 134 formed on the substrate 132, and a lower portion of the substrate 132. The light diffusing layer 136 and the low refractive index layer 138 formed between the substrate 132 and the light diffusing layer 136 may be included.

The substrate 132 may transmit light incident from an external light source. The substrate 132 may be formed to include any one material selected from the group consisting of a light transmissive material, for example, polyethylene terephthalate, polycarbonate, polypropylene, polyethylene, polystyrene, and polyepoxy, but is not limited thereto. Do not.

The light collecting pattern 134 may collect light incident from an external light source, and may be formed of a prism pattern 134a.

Specifically, the prism pattern 134a has a triangular shape on its cross section, that is, a YZ plane, and is linearly formed along the X-axis direction in the longitudinal direction of the prism pattern 134a, thereby forming a triangular prism rod in appearance. It may be formed as, but is not limited thereto.

The height h1 of the prism pattern 134a may be constant along the X-axis direction. In this case, the height h1 of the prism pattern 134a may vary along the Y-axis direction to prevent moire from occurring in the backlight unit and the liquid crystal display including the optical sheet 130. have. That is, in each prism pattern 134a, the height h1 of the prism pattern 134a is constant along the X-axis direction, but a height difference may occur between the prism patterns 134a. However, the optical sheet 130 of the present invention is not limited to the above description, and the height h1 of the prism pattern 134a may be constant along the Y-axis direction. Here, the height h1 of the prism pattern 134a may vary depending on specifications of the backlight unit including the optical sheet 130 and the liquid crystal display, and is not particularly limited.

The prism pattern 134a may include, for example, a polymer resin capable of UV curing, specifically, a polymer resin of any one of an acrylate series and a polyolefin series. Here, examples of the acrylate series include urethane acrylate and epoxy acrylate, and examples of the polyolefin series include polysiloxane and polyether.

The refractive index of the condensing pattern 134 including the prism pattern 134a may be 1.5 to 1.6. When the refractive index of the light collecting pattern 134 is out of the above range, the light collecting efficiency by the light collecting pattern 134 may be reduced, so that the refractive index of the light collecting pattern 134 is 1.5 to 1.6, thereby preventing the light collecting pattern 134 from being collected by the light collecting pattern 134. Condensing efficiency can be secured.

The light diffusion layer 136 may diffuse light incident from an external light source, and may include a binder resin 136a and light diffusion particles 136b. Here, the light diffusing layer 136 may be formed on one surface of the low refractive index layer 138 by, for example, any one of a knife coating, roll coating, and gravure coating method. May, but is not limited to.

The binder resin 136a allows the light diffusion particles 136b dispersed therein to be formed on one surface of the low refractive index layer 138.

The binder resin 136a may be a resin having good adhesion with the low refractive index layer 138 and good compatibility with the light diffusing particles 136b. For example, as the binder resin 136a, unsaturated polyester, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, normal butyl methyl methacrylate, acrylic acid, methacrylic acid, and hydride Hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxy ethyl acrylate, acrylamide, metyrol acrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, normal butyl acrylate, 2- Acrylic, urethane, epoxy, melamine, etc., such as an ethylhexyl acrylate polymer, a copolymer, or a terpolymer, can be used.

The light diffusing particles 136b may diffuse light incident from an external light source.

As the light diffusing particles 136b, organic particles having high light transmittance and high light diffusing rate may be used. For example, as the light diffusing particles 136b, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, normal butyl methyl methacrylate, acrylic acid, methacrylic acid and hydroxyethyl methacrylate. Acrylate, hydroxypropyl methacrylate, hydroxy ethyl acrylate, acrylamide, methrol acrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, normal butyl acrylate, 2-ethylhexyl acryl Olefinic particles such as acrylate polymers, copolymers or terpolymers, olefinic particles such as polyethylene, polystyrene, polypropylene, copolymers of acrylic and olefins, and homopolymers are formed and then covered with other monomers on the layers. Organic particles, such as multilayer multicomponent particle | grains made by covering, can be used.

Some of the light diffusing particles 136b of the light diffusing particles 136b may protrude from the lower surface of the light diffusing layer 136 to some extent, but are not limited thereto.

The refractive index of the light diffusing layer 136 having the above-described configuration may be 1.5 to 1.6. When the refractive index of the light diffusing layer 136 is out of the above range, the light diffusing efficiency by the light diffusing layer 136 may be reduced, so that the refractive index of the light diffusing layer 136 is set to 1.5 to 1.6 to the light diffusing layer 136. Light diffusion efficiency can be ensured.

The low refractive index layer 138 may have a refractive index smaller than that of each of the light collecting pattern 134 and the light diffusing layer 136, thereby generating a difference in refractive index between the light collecting pattern 134 and the light diffusing layer 136.

This will be described below in connection with the background art. In the backlight unit according to the background art, since an air layer having a refractive index of 1 exists between the diffusion sheet and the prism sheet that are sequentially stacked during the assembly process, the light diffused by the diffusion sheet is scattered by the air layer, Can be condensed by.

However, if the low refractive index layer 138 is not present in the optical sheet 130 according to the embodiment of the present invention, the light diffused by the light diffusing layer 136 may not be collected by the light collecting pattern 134. . This is because the refractive indexes of the light diffusing layer 136 and the light collecting pattern 134 of the optical sheet 130 according to the exemplary embodiment are the same or similar.

Therefore, in the light diffusing sheet according to the embodiment of the present invention, the light collecting pattern 134 and the light diffusing layer 136 play a role similar to that of the air layer according to the background technology, specifically, between the substrate 132 and the light diffusing layer 136. By forming a low refractive index layer 138 that can be performed, the light diffused by the light diffusing layer 136 is scattered by the low refractive index layer 138, and then to be focused by the light collecting pattern 134.

In order for the low refractive index layer 138 to play a role similar to that of the air layer according to the background art, the low refractive index layer 138 needs to have a refractive index smaller than 0.1 or less than 0.6 than the refractive index of the light converging pattern 134. In addition, it is necessary for the low refractive index layer 138 to have a refractive index smaller than 0.1 and less than 0.6 than the refractive index of the light diffusion layer 136. Here, the reason why the refractive index of the low refractive index layer 138 is smaller than 0.1 by the refractive index of each of the light converging pattern 134 and the light diffusing layer 136 is to ensure a minimum value for scattering light through the low refractive index layer 138. For sake.

Since the refractive index of the low refractive index layer 138 is dependent on the refractive indices of each of the light converging pattern 134 and the light diffusing layer 136, the refractive index is not particularly limited, but may be greater than 1 and 1.4 or less.

The low refractive index layer 138 may include a material having a light transmittance and a low refractive index, and is not particularly limited, but may include a fluorine-containing material. Examples of the fluorine-containing material include amorphous fluorine (refractive index: about 1.3), cryolite (Na3AlF6; refractive index: 1.33), magnesium fluoride (MgF2; refractive index: about 1.4), and the like.

On the other hand, Figure 3 is a perspective view for explaining an optical sheet according to an embodiment of the present invention. 4 is a cross-sectional view for describing in detail the optical sheet shown in FIG. 3. Since the optical sheet shown in FIG. 3 is the same as that shown in FIG. 1 except that the low refractive index layer includes bubbles, overlapping descriptions will be omitted and only the features thereof will be described.

3 and 4, the optical sheet 140 according to the exemplary embodiment of the present invention may be provided in the backlight unit of the liquid crystal display.

The optical sheet 140 may diffuse and collect light incident from an external light source, and the substrate 142, a light collecting pattern 144 formed on the substrate 142, and a lower portion of the substrate 142. The light diffusing layer 146 and the low refractive index layer 148 formed between the substrate 142 and the light diffusing layer 146 may be included. Here, the substrate 142, the light collecting pattern 144, and the light diffusion layer 146 are the same as those described with reference to FIGS. 1 and 2, and thus the detailed description thereof will be omitted. On the other hand, reference numeral 144a denotes a prism pattern of the light converging pattern 144, and reference numerals 146a and 146b each denote a binder resin and light diffusing particles of the light diffusion layer 146, respectively.

The low refractive index layer 148 may have a refractive index smaller than that of each of the light collecting pattern 144 and the light diffusing layer 146, thereby generating a difference in refractive index between the light collecting pattern 144 and the light diffusing layer 146. Since this is the same as described above, the detailed description thereof will be omitted.

Specifically, the low refractive index layer 148 may have a refractive index that is less than 0.1 or less than 0.6 than the refractive index of the light converging pattern 144. In addition, the low refractive index layer 148 may have a refractive index less than 0.1 or less than 0.6 than the refractive index of the light diffusion layer 146. Since this is the same as described above, the detailed description thereof will be omitted.

Since the refractive index of the low refractive index layer 148 is dependent on the refractive index of each of the light converging pattern 144 and the light diffusing layer 146, the refractive index is not particularly limited, but may be more than 1 and 1.4 or less.

The low refractive index layer 148 may include bubbles 148a randomly distributed therein. For this reason, the lower surface of the low refractive index layer 148 may be formed to have concave portions and / or convex portions, but is not limited thereto.

The bubble 148a may be formed through pyrolysis of a blowing agent. Here, the blowing agent is a kind of chemical blowing agent, specifically, an organic compound that releases a gas, for example, nitrogen or carbon dioxide, which is one or more bubbles 148a by thermal decomposition at a thermal decomposition temperature or higher of the blowing agent by a heating process. Say. As the blowing agent, an azo compound represented by azodicarbonamide, azobisisobutyronitrile, and the like, a sulfonylhydrazide compound represented by p, p'-oxybisbenzinesulfonylhydrazide, and the like can be used. It is not limited to this.

If at least one or more of the diameter and density of the bubble 148a is large, the refractive index of the low refractive index layer 148 may be close to 1, but the mechanical strength of the optical sheet 140 may be deteriorated. Therefore, the diameter and density of the bubble 148a may be appropriately selected within the limits of securing the refractive index of the low refractive index layer 148 and the mechanical strength of the optical sheet 140 in consideration of the thickness of the low refractive index layer 148. Therefore, it is not limited.

On the other hand, Figure 5 is a perspective view for explaining an optical sheet according to an embodiment of the present invention. 6 is a cross-sectional view for describing in detail the optical sheet shown in FIG. 5. Since the optical sheet shown in FIG. 5 is the same as that shown in FIG. 1 except that the height of the prism pattern constituting the light collecting pattern is randomly changed along the length direction of the prism pattern, overlapping description is omitted. Only its features will be described.

5 and 6, an optical sheet 150 according to an embodiment of the present invention may be provided in a backlight unit of a liquid crystal display.

The optical sheet 150 may diffuse and collect light incident from an external light source, and may be formed on the substrate 152, the light collecting pattern 154 formed on the substrate 152, and a lower portion of the substrate 152. The light diffusing layer 156 and the low refractive index layer 158 formed between the substrate 152 and the light diffusing layer 156 may be included. Here, the substrate 152, the light diffusing layer 156 and the low refractive index layer 158 are the same as those described with reference to FIGS. 1 and 2, and thus the detailed description thereof will be omitted. On the other hand, reference numerals 156a and 156b each represent a binder resin and light diffusing particles of the light diffusion layer 156.

The light collecting pattern 154 may collect light incident from an external light source, and may be formed of a prism pattern 154a.

The height h3 of the prism pattern 154a may be randomly varied along the X-axis direction, which is the longitudinal direction of the prism pattern 154a. Through this, moire may be further prevented from occurring in the backlight unit and the liquid crystal display including the optical sheet 150. Here, the degree of the change in the height h3 of the prism pattern 154a may vary depending on the specifications of the backlight unit and the liquid crystal display device including the optical sheet 150, and is not particularly limited. Other features of the light collecting pattern 154 are the same as those of the detailed description with reference to FIGS. 1 and 2, and thus the detailed description thereof will be omitted.

On the other hand, Figure 7 is a perspective view for explaining an optical sheet according to an embodiment of the present invention. 8 is a cross-sectional view for describing in detail the optical sheet illustrated in FIG. 7. Since the optical sheet shown in FIG. 7 is the same as that shown in FIG. 5 except that the low refractive index layer includes bubbles, overlapping descriptions will be omitted and only features thereof will be described.

7 and 8, an optical sheet 160 according to an embodiment of the present invention may be provided in a backlight unit of a liquid crystal display.

The optical sheet 160 may diffuse and focus light incident from an external light source, and may be formed on the substrate 162, the light collecting pattern 164 formed on the substrate 162, and a lower portion of the substrate 162. The light diffusing layer 166 and the low refractive index layer 168 formed between the substrate 162 and the light diffusing layer 166 may be included. Here, the substrate 162 and the light diffusion layer 166 are the same as the detailed description with reference to FIGS. 1 and 2, and the light collecting pattern 164 is the same as the detailed description with reference to FIGS. 5 and 6, and thus the detailed description is omitted. do. On the other hand, reference numeral 164a denotes a prism pattern of the light converging pattern 164, and reference numerals 166a and 166b each denote a binder resin and light diffusing particles of the light diffusion layer 166, respectively.

The low refractive index layer 168 may include bubbles 168a randomly distributed therein. For this reason, the lower surface of the low refractive index layer 168 may be formed to have concave portions and / or convex portions, but is not limited thereto. Here, the low refractive index layer 168 is the same as the detailed description with reference to FIGS. 3 and 4, the detailed description thereof will be omitted.

9 is a perspective view illustrating an optical sheet according to an embodiment of the present invention. 10 is a cross-sectional view for describing in detail the optical sheet shown in FIG. 9. Since the optical sheet shown in FIG. 9 is the same as that shown in FIG. 1 except that the condensing pattern is composed of a prism pattern and a micro lens pattern, overlapping description is omitted and only its features will be described.

9 and 10, an optical sheet 170 according to an embodiment of the present invention may be provided in a backlight unit of a liquid crystal display.

The optical sheet 170 may diffuse and collect light incident from an external light source, and the substrate 172, a light collecting pattern 174 formed on the substrate 172, and a lower portion of the substrate 172. The light diffusing layer 176 and the low refractive index layer 178 formed between the substrate 172 and the light diffusing layer 176 may be included. Here, since the substrate 172, the light diffusing layer 176 and the low refractive index layer 178 is the same as the detailed description with reference to Figs. 1 and 2, the detailed description thereof will be omitted. On the other hand, reference numerals 176a and 176b each represent a binder resin and light diffusing particles of the light diffusing layer 176.

The light collecting pattern 174 may collect light incident from an external light source, and may include a prism pattern 174a and a micro lens pattern 174b. Here, since the prism pattern 174a is the same as the detailed description with reference to FIGS. 1 and 2, the detailed description thereof will be omitted.

The micro lens pattern 174b may be formed between the prism patterns 174a. In this case, the micro lens pattern 174b and the prism pattern 174a may be alternately formed, but are not limited thereto.

Specifically, the microlens pattern 174b has a shape of a partial arc or a partial ellipse on its cross section, that is, the YZ plane, and is linearly formed along the X-axis direction in the longitudinal direction of the microlens pattern 174b. As a result, it may be formed in a partial cylindrical shape or a partial elliptic cylinder in appearance, but is not limited thereto. Here, the micro lens pattern 174b may be, for example, a lenticular lens pattern, but is not limited thereto.

The micro lens pattern 174b may be formed of the same material as the prism pattern 174a. Accordingly, the refractive index of the light collecting pattern 174 including the micro lens pattern 174b and the prism pattern 174a may be 1.5 to 1.6. Other features of the light collecting pattern 174 are the same as those described with reference to FIGS. 1 and 2, and thus the detailed description thereof will be omitted.

On the other hand, Figure 11 is a perspective view for explaining an optical sheet according to an embodiment of the present invention. 12 is a cross-sectional view for describing in detail the optical sheet illustrated in FIG. 11. Since the optical sheet shown in FIG. 11 is the same as that shown in FIG. 9 except that the low refractive index layer includes bubbles, overlapping descriptions will be omitted and only the features thereof will be described.

11 and 12, an optical sheet 180 according to an embodiment of the present invention may be provided in a backlight unit of a liquid crystal display.

The optical sheet 180 may diffuse and collect light incident from an external light source, and the substrate 182, a light collecting pattern 184 formed on the substrate 182, and a lower portion of the substrate 182. The light diffusing layer 186 and the low refractive index layer 188 formed between the substrate 182 and the light diffusing layer 186 may be included. Here, since the substrate 182 and the light diffusing layer 186 are the same as the detailed description with reference to FIGS. 1 and 2, and the light collecting pattern 184 is the same as the detailed description with reference to FIGS. 9 and 10, the detailed description is omitted. do. On the other hand, reference numerals 184a and 184b each denote a prism pattern and a micro lens pattern of the light converging pattern 184, and each of reference numerals 186a and 186b denotes a binder resin and light diffusing particles of the light diffusion layer 186, respectively.

The low refractive index layer 188 may include bubbles 188a randomly distributed therein. For this reason, the lower surface of the low refractive index layer 188 may be formed to have concave portions and / or convex portions, but is not limited thereto. Here, the low refractive index layer 188 is the same as the detailed description with reference to FIGS. 3 and 4, the detailed description thereof will be omitted.

13 is a perspective view illustrating an optical sheet according to an embodiment of the present invention. 14 is a cross-sectional view for describing in detail the optical sheet illustrated in FIG. 13. Since the optical sheet shown in FIG. 13 is the same as that shown in FIG. 9 except that the height of the prism pattern of the condensing pattern is randomly changed along the length direction of the prism pattern, overlapping description is omitted and Only the features will be described.

13 and 14, an optical sheet 190 according to an embodiment of the present invention may be provided in a backlight unit of a liquid crystal display.

The optical sheet 190 may diffuse and collect light incident from an external light source, and the substrate 192, a light collecting pattern 194 formed on the substrate 192, and a lower portion of the substrate 192. The light diffusing layer 196 and the low refractive index layer 198 formed between the substrate 192 and the light diffusing layer 196 may be included. Here, since the substrate 192, the light diffusing layer 196 and the low refractive index layer 198 are the same as those described with reference to FIGS. 1 and 2, the detailed description thereof will be omitted. In addition, each of 196a and 196b denotes the binder resin and the light diffusing particles of the light diffusion layer 196.

The light collecting pattern 194 may collect light incident from an external light source, and may include a prism pattern 194a and a micro lens pattern 194b. Here, since the microlens pattern 194b is the same as the detailed description with reference to FIGS. 9 and 10, the detailed description thereof will be omitted.

The height h7 of the prism pattern 194a may vary randomly along the X-axis direction, which is the longitudinal direction of the prism pattern 194a. This is the same as the detailed description with reference to FIGS. 5 and 6, the detailed description thereof will be omitted.

15 is a perspective view illustrating an optical sheet according to an embodiment of the present invention. 16 is a cross-sectional view for describing in detail the optical sheet shown in FIG. 15. Since the optical sheet shown in FIG. 15 is the same as that shown in FIG. 13 except that the low refractive index layer includes bubbles, overlapping description is omitted and only the features thereof will be described.

15 and 16, an optical sheet 200 according to an embodiment of the present invention may be provided in a backlight unit of a liquid crystal display.

The optical sheet 200 may diffuse and condense the light incident from an external light source, and may collect the substrate 202, the light collecting pattern 204 formed on the substrate 202, and a lower portion of the substrate 202. The light diffusing layer 206 is formed, and the low refractive index layer 208 formed between the substrate 202 and the light diffusing layer 206. Here, since the substrate 202 and the light diffusing layer 206 are the same as the detailed description with reference to FIGS. 1 and 2, and the light collecting pattern 204 is the same as the detailed description with reference to FIGS. 13 and 14, the detailed description is omitted. do. On the other hand, reference numerals 204a and 204b each denote a prism pattern and a micro lens pattern of the light converging pattern 204, and each of the reference numerals 206a and 206b denotes a binder resin and light diffusing particles of the light diffusion layer 206, respectively.

The low refractive index layer 208 may include bubbles 208a randomly distributed therein. For this reason, the lower surface of the low refractive index layer 208 may be formed to have concave portions and / or convex portions, but is not limited thereto. Here, the low refractive index layer 208 is the same as the detailed description with reference to FIGS. 3 and 4, the detailed description thereof will be omitted.

According to the above-described embodiments of the present invention, the light condensing and diffusing functions of the light may be realized through one sheet of optical sheet. For this reason, cost reduction and thickness reduction of the backlight unit and liquid crystal display device provided with the said optical sheet can be achieved. In addition, the assembly process may be simplified by reducing the number of optical sheets required in the assembly process of the backlight unit and the liquid crystal display. As a result, productivity of the backlight unit and the liquid crystal display may be improved.

17 is an exploded perspective view for describing the configuration of a backlight unit according to an embodiment of the present invention. FIG. 18 is a cross-sectional view taken along the line II ′ of FIG. 17. In FIG. 17, an edge type backlight unit is illustrated as the backlight unit, but the present invention is not limited thereto. In addition, although FIG. 17 shows the optical sheet shown in FIG. 1 as an optical sheet, the present invention is not limited thereto, and the optical sheet is illustrated in FIGS. 3, 5, 7, 7, 9, 11, 13 and Any one of the optical sheets shown in FIG. 15 may be employed.

17 and 18, the backlight unit 210 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 210 may include a light source 220 and an optical sheet 130. In addition, the backlight unit 210 may further include a light guide plate 240, a reflective plate 250, a bottom cover 260, and a mold frame 270.

The light source 220 may generate light by using driving power applied from the outside, and may emit the generated light.

For example, at least one light source 220 may be formed on one side of the light guide plate 240 along the X axis direction, which is the long axis direction of the light guide plate 240, or both sides of the light guide plate 240 along the X axis direction. At least one or more may be formed in each. Here, the light emitted from the light source 220 is incident directly into the light guide plate 240, or the light source housing 222 formed to surround a portion of the light source 220, for example, about 3/4 of the outer peripheral surface of the light source 220 After the light is reflected, the light guide plate 240 may be incident into the light guide plate 240.

Specifically, the light source 220 may include 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 130 may be disposed on the light guide plate 240. After the optical sheet 130 is emitted from the light source 220, the optical sheet 130 collects and diffuses light incident on the optical sheet 130 through the light guide plate 240, thereby providing optical characteristics of the backlight unit 210. Luminance and luminance uniformity can be improved.

The optical sheet 130 includes a substrate 132, a light collecting pattern 134 formed on an upper portion of the substrate 132, a light diffusion layer 136 formed on the lower portion of the substrate 132, and the substrate 132 and the It may include a low refractive index layer 138 formed between the light diffusion layer 136. Here, since the substrate 132, the light collecting pattern 134, the light diffusing layer 136, and the low refractive index layer 138 are the same as those described with reference to FIGS. 1 and 2, the detailed description thereof will be omitted.

The light guide plate 240 may be disposed to face the light source 220, and may guide the light so that the light incident from the light source 220 is emitted upward.

The reflector 250 may be disposed under the light guide plate 240, and may reflect light emitted downward through the light guide plate 240 among the light emitted from the light source 220.

The bottom cover 260 may include a bottom part 262 and a side part 264 formed to extend from the bottom part 262 to form an accommodation space, and the light source 220 and the optical sheet 130 may be formed in the accommodation space. The light guide plate 240 and the reflector 250 may be accommodated.

The mold frame 270 is formed in a substantially rectangular frame shape and is fastened with the bottom cover 260 in a top down manner from an upper side of the bottom cover 260, thereby preventing the flow of the optical sheet 130. have.

The backlight unit 210 according to the exemplary embodiment of the present invention described above includes a single optical sheet 130 having a function of condensing and diffusing light simultaneously. Through this, not only the cost of the backlight unit 210 may be reduced, but the thickness of the backlight unit 210 may be manufactured. In addition, since the assembling process of the backlight unit 210 may be simplified, productivity of the backlight unit 210 may be improved.

19 is an exploded perspective view for describing a configuration of a backlight unit according to an embodiment of the present invention. 20 is a cross-sectional view taken along the line II-II ′ of FIG. 19. 19 illustrates a direct backlight unit as the backlight unit, but the present invention is not limited thereto. Since the backlight unit illustrated in FIG. 19 is substantially the same as the backlight unit illustrated in FIG. 17 except for the arrangement of light sources and a change in components thereof, the descriptions thereof will not be repeated and only the features thereof will be described. . In addition, although FIG. 19 shows the optical sheet shown in FIG. 1 as an optical sheet, the present invention is not limited thereto, and the optical sheet is illustrated in FIGS. 3, 5, 7, 7, 9, 11, 13 and Any one of the optical sheets shown in FIG. 15 may be employed.

19 and 20, the backlight unit 310 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 310 may include a light source 320 and an optical sheet 130. In addition, the backlight unit 310 may further include a reflecting plate 350, a bottom cover 360, a mold frame 370, and a diffusion plate 380.

At least one light source 320 may be disposed under the diffuser plate 380. For this reason, the light emitted from the light source 320 may be incident directly to the diffuser plate 380.

The optical sheet 130 may be disposed on the diffuser plate 380. The optical sheet 130 emits light from the light source 320 and then collects and diffuses light incident on the optical sheet 130 via the diffuser plate 380, thereby, for example, optical characteristics of the backlight unit 310. , Brightness and luminance uniformity can be improved.

The optical sheet 130 includes a substrate 132, a light collecting pattern 134 formed on an upper portion of the substrate 132, a light diffusion layer 136 formed on the lower portion of the substrate 132, and the substrate 132 and the It may include a low refractive index layer 138 formed between the light diffusion layer 136. Here, since the substrate 132, the light collecting pattern 134, the light diffusing layer 136, and the low refractive index layer 138 are the same as those described with reference to FIGS. 1 and 2, the detailed description thereof will be omitted.

The diffusion plate 380 may be disposed between the light source 320 and the optical sheet 130, and may diffuse light incident from the light source 320 upward. This is to prevent the shape of the light source 320 from being visible through the backlight unit 310 and to further diffuse the light.

The backlight unit 310 according to the exemplary embodiment of the present invention described above includes a sheet of optical sheet 130 having a function of condensing and diffusing light simultaneously. Through this, not only the cost of the backlight unit 310 may be reduced, but the thickness of the backlight unit 310 may be manufactured. In addition, since the assembling process of the backlight unit 310 may be simplified, productivity of the backlight unit 310 may be improved.

FIG. 21 is an exploded perspective view illustrating a configuration of a liquid crystal display according to an exemplary embodiment of the present invention. FIG. 22 is a cross-sectional view taken along the line III-III ′ of FIG. 21. In FIG. 21, the backlight unit illustrated in FIG. 17 is illustrated as the backlight unit. However, the present invention is not limited thereto, and the backlight unit illustrated in FIG. 19 may be employed as the backlight unit. Meanwhile, since the backlight unit illustrated in FIG. 21 is the same as described above, overlapping descriptions are omitted and only the features thereof will be described.

21 and 22, the liquid crystal display device 400 according to an exemplary embodiment may display an image by using the electro-optical characteristics of the liquid crystal.

The liquid crystal display device 400 may include a backlight unit 210 and a liquid crystal panel 410.

The backlight unit 210 may be mounted under the liquid crystal panel 410 and may provide light to the liquid crystal panel 410.

The backlight unit 210 may include a light source 220 and an optical sheet 130. In addition, the backlight unit 210 may further include a light guide plate 240, a reflective plate 250, a bottom cover 260, and a mold frame 270.

The liquid crystal panel 410 is seated on the mold frame 270 and may be fixed by the top cover 420 fastened to the bottom cover 260 in a top down manner.

The liquid crystal panel 410 may display an image using light provided from the backlight unit 210, specifically, light emitted from the light source 220.

The liquid crystal panel 410 may include a color filter substrate 412 and a thin film transistor substrate 414 facing each other with the liquid crystal interposed therebetween.

The color filter substrate 412 may implement colors of an image displayed through the liquid crystal panel 410.

The color filter substrate 412 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 412.

The thin film transistor substrate 414 is electrically connected to the printed circuit board 418 on which a plurality of circuit components are mounted through the driving film 416. The thin film transistor substrate 414 may apply a driving voltage provided from the printed circuit board 418 to the liquid crystal in response to a driving signal provided from the printed circuit board 418.

The thin film transistor substrate 414 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 414.

Since the liquid crystal display 400 according to the exemplary embodiment of the present invention includes a single optical sheet 130 having both light diffusion and light condensing functions, cost reduction and thinning of the liquid crystal display 400 can be achieved. Can be. In addition, since the assembly process of the liquid crystal display device 400 may be simplified, productivity of the liquid crystal display device 400 may be improved.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can realize that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. I can understand that.

Therefore, since the embodiments described above are provided to completely inform the scope of the invention to those skilled in the art, it should be understood that they are exemplary in all respects and not limited. The invention is only defined by the scope of the claims.

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

2 is a cross-sectional view for describing in detail the optical sheet shown in FIG. 1.

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

4 is a cross-sectional view for describing in detail the optical sheet shown in FIG. 3.

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

6 is a cross-sectional view for describing in detail the optical sheet shown in FIG. 5.

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

8 is a cross-sectional view for describing in detail the optical sheet illustrated in FIG. 7.

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

10 is a cross-sectional view for describing in detail the optical sheet illustrated in FIG. 9.

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

12 is a cross-sectional view for describing in detail the optical sheet illustrated in FIG. 11.

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

14 is a cross-sectional view for describing in detail the optical sheet illustrated in FIG. 13.

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

16 is a cross-sectional view for describing in detail the optical sheet shown in FIG. 15.

17 is an exploded perspective view illustrating the configuration of a backlight unit according to an embodiment of the present invention.

FIG. 18 is a cross-sectional view taken along the line II ′ of FIG. 17.

19 is an exploded perspective view for describing a configuration of a backlight unit according to an embodiment of the present invention.

20 is a cross-sectional view taken along the line II-II ′ of FIG. 19.

FIG. 21 is an exploded perspective view illustrating a configuration of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 22 is a cross-sectional view taken along the line III-III ′ of FIG. 21.

{Description of symbols for main parts of the drawing}

130/140/150/160/170/180/190/200: optical sheet

132/142/152/162/172/182/192/202: description

134/144/154/164/174/184/194/204: condensing pattern

136/146/156/166/176/186/196/206: light diffusion layer

138/148/158/168/178/188/198/208: low refractive index layer

210/310: backlight unit 220/320: light source

400: liquid crystal display 410: liquid crystal panel

Claims (29)

A substrate for transmitting light incident from the outside; A condensing pattern formed on the substrate and condensing light incident from the outside; A light diffusion layer formed under the substrate and diffusing light incident from the outside; And A low refractive index layer formed between the substrate and the light diffusion layer Optical sheet comprising a. The method of claim 1, wherein the condensing pattern, Prism pattern with triangular cross-sectional shape Optical sheet comprising a. The method of claim 2, wherein the light collecting pattern, A micro lens pattern formed between the prism patterns and having a cross-sectional shape of a partial arc or a partial ellipse arc. Optical sheet comprising more. The method according to claim 2 or 3, The height of the prism pattern is constant along the longitudinal direction of the prism pattern, the optical sheet. The method of claim 4, wherein The height of the prism pattern is constant along the longitudinal direction of the prism pattern, characterized in that the optical sheet is variable in a direction perpendicular to the longitudinal direction of the prism pattern. The method according to claim 2 or 3, The height of the prism pattern is randomly varying along the longitudinal direction of the prism pattern. The method of claim 1, The low refractive index layer has a refractive index smaller than the refractive index of each of the light converging pattern and the light diffusing layer. The method of claim 7, wherein And the low refractive index layer comprises a fluorine-containing material. The method of claim 7, wherein The low refractive index layer is an optical sheet, characterized in that it comprises bubbles (138a) randomly distributed inside the low refractive index layer. The method of claim 7, wherein The low refractive index layer has an index of refraction of less than 0.1 or less than 0.6 less than the refractive index of the light converging pattern. The method of claim 7, wherein The low refractive index layer has an index of refraction of 0.1 to 0.6 less than the refractive index of the light diffusing layer. The method of claim 7, wherein The refractive index of the said low refractive index layer is more than 1 and 1.4 or less, The optical sheet characterized by the above-mentioned. The method of claim 7, wherein The refractive index of the said condensing pattern is 1.5 or more and 1.6 or less, The optical sheet characterized by the above-mentioned. The method of claim 7, wherein The refractive index of the said light-diffusion layer is 1.5 or more and 1.6 or less, The optical sheet characterized by the above-mentioned. A light source for emitting light; And An optical sheet for collecting and diffusing light incident from the light source Including; The optical sheet, A substrate that transmits light incident from the light source; A condensing pattern formed on the substrate and condensing light incident from the light source; A light diffusion layer formed under the substrate and diffusing light incident from the light source; And A low refractive index layer formed between the substrate and the light diffusion layer Backlight unit comprising a. The method of claim 15, wherein the light collecting pattern of the optical sheet, Prism pattern with triangular cross-sectional shape Backlight unit comprising a. The method of claim 16, wherein the light collecting pattern of the optical sheet, A micro lens pattern formed between the prism patterns and having a cross-sectional shape of a partial arc or a partial ellipse arc. The backlight unit further comprises. The method according to claim 16 or 17, And a height of the prism pattern is constant along a length direction of the prism pattern. The method of claim 18, The height of the prism pattern is constant along the longitudinal direction of the prism pattern, it is variable in the direction perpendicular to the longitudinal direction of the prism pattern. The method according to claim 16 or 17, The height of the prism pattern is randomly variable along the longitudinal direction of the prism pattern. The method of claim 15, And the low refractive index layer of the optical sheet has a refractive index smaller than that of each of the light converging pattern and the light diffusing layer of the optical sheet. The method of claim 21, The low refractive index layer is a backlight unit, characterized in that containing a fluorine-containing material. The method of claim 21, The low refractive index layer is a backlight unit, characterized in that it comprises bubbles (138a) randomly distributed inside the low refractive index layer. The method of claim 21, The low refractive index layer has a refractive index of less than 0.1 or less than 0.6 than the refractive index of the light converging pattern. The method of claim 21, The low refractive index layer has a refractive index of less than 0.1 or less than 0.6 than the refractive index of the light diffusing layer. The method of claim 21, And a refractive index of the low refractive index layer is greater than 1 and less than or equal to 1.4. The method of claim 21, And a refractive index of the condensing pattern is 1.5 or more and 1.6 or less. The method of claim 21, And a refractive index of the light diffusion layer is 1.5 or more and 1.6 or less. A light source for emitting light; An optical sheet for collecting and diffusing light incident from the light source; And Liquid crystal panel for displaying an image using the light emitted from the light source Including; The optical sheet, A substrate that transmits light incident from the light source; A condensing pattern formed on the substrate and condensing light incident from the light source; A light diffusion layer formed under the substrate and diffusing light incident from the light source; And A low refractive index layer formed between the substrate and the light diffusion layer Liquid crystal display comprising a.

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