KR100863773B1 - Diffuse sheet and backlight assembly and liquid crystal display comprising the same - Google Patents

Abstract

Provided are a diffusion sheet, a backlight assembly including the same, and a liquid crystal display device. The diffusion sheet includes a transparent substrate and a plurality of diffusion arrays including a plurality of diffusion patterns having a three-dimensional shape on the transparent substrate, wherein the diffusion patterns included in the diffusion array have a diameter of which gradually increases depending on the position of the diffusion array. Changes to According to the diffusion sheet, the backlight assembly and the liquid crystal display including the same, the diffusion pattern whose diameter varies depending on the position of the diffusion array in the diffusion sheet, thereby simultaneously improving the viewing angle and luminance characteristics of the liquid crystal display. have.

Liquid crystal display, optical member, diffusion sheet, diffusion pattern

Description

Diffuse sheet and backlight assembly and liquid crystal display comprising the same

1A is a plan view of a diffusion sheet according to an embodiment of the present invention.

FIG. 1B is a cross-sectional view taken along the line BB ′ of FIG. 1A.

1C is a perspective view of a diffusion sheet according to an embodiment of the present invention.

2A is a plan view of a diffusion sheet according to another embodiment of the present invention.

FIG. 2B is a cross-sectional view taken along the line BB ′ of FIG. 2A.

2C is a perspective view of a diffusion sheet according to another embodiment of the present invention.

3 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

4 is a cross-sectional view of a backlight assembly according to an embodiment of the present invention.

5 is an exploded perspective view of a liquid crystal display according to another exemplary embodiment of the present invention.

6 is a cross-sectional view of a backlight assembly according to another embodiment of the present invention.

7A and 7B are graphs showing results of luminance and viewing angles of diffusion sheets according to embodiments and comparative examples.

<Description of the symbols for the main parts of the drawings>

10: transparent substrate 20, 21: diffusion pattern

100, 110: diffusion sheet 200, 200 ': liquid crystal display device

211, 211 ': Light guide plate

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

The liquid crystal display is one of flat panel displays that display an image by using the electrical and optical characteristics of a liquid crystal having intermediate characteristics between a liquid and a solid. Liquid crystal display devices are thinner and lighter than other display devices, and have advantages of low driving voltage and low power consumption, and thus are widely used throughout the industry.

The liquid crystal display is a non-light emitting device in which a liquid crystal display panel for displaying an image does not emit light by itself, and thus requires a backlight assembly for supplying additional light.

In general, the backlight assembly includes a light source, a light guide plate for guiding light emitted from the light source, a diffusion sheet disposed on the light guide plate to diffuse light emitted from the light guide plate, and a prism sheet for collecting light emitted from the diffusion sheet.

However, the diffusion sheet may cause a considerable proportion of light loss in the process of diffusing the light generated from the light source, which in turn may lower the viewing angle and luminance of the liquid crystal display device.

The technical problem to be achieved by the present invention is to provide a diffusion sheet that can improve the viewing angle and brightness.

Another object of the present invention is to provide a backlight assembly including a diffusion sheet capable of improving viewing angle and brightness.

Another object of the present invention is to provide a liquid crystal display device including a diffusion sheet capable of improving the viewing angle and brightness.

Diffusion sheet according to an embodiment of the present invention for achieving the technical problem has a plurality of diffusion array including a transparent substrate, and a plurality of diffusion patterns having a three-dimensional shape on the transparent substrate, within the diffusion array The diameter of the diffusion pattern is gradually changed according to the position of the diffusion array.

In this case, the diffusion pattern may gradually increase in diameter from the diffusion array positioned at one end of the transparent substrate to the diffusion array positioned at the other end of the transparent substrate.

In addition, the diffusion pattern may gradually increase in diameter from the diffusion array positioned at both ends of the transparent substrate to the diffusion array positioned at the center of the transparent substrate.

In addition, the diffusion pattern may have a diameter of 30 to 80㎛, the height of the diffusion pattern may have a value corresponding to 50% or less of the diameter of the diffusion pattern.

According to another aspect of the present invention, there is provided a backlight assembly including a light guide plate, a light source positioned on at least one side of the light guide plate, a transparent substrate facing the light guide plate, and a three-dimensional shape on the transparent substrate. The diffusion pattern includes a plurality of diffusion arrays including a plurality of diffusion patterns, wherein the diffusion pattern included in the diffusion array includes a diffusion sheet whose diameter gradually changes depending on the position of the diffusion array.

In this case, the light source is located on one side of the light guide plate, and the diffusion pattern has a size of a diameter from the diffusion array located at one end of the transparent substrate corresponding to the light source to the diffusion array located at the other end of the transparent substrate. Can grow gradually.

In addition, the light sources are respectively located at both sides of the light guide plate, and the diffusion pattern is gradually moved from the diffusion array located at both ends of the transparent substrate corresponding to the light source to the diffusion array located at the center of the transparent substrate. The size of the diameter can gradually increase.

In addition, the diffusion pattern may have a diameter of 30 to 80㎛, the height of the diffusion pattern may have a value corresponding to 50% or less of the diameter of the diffusion pattern.

The liquid crystal display according to the exemplary embodiment of the present invention for achieving the another technical problem may include a backlight assembly as described above.

Specific details of other embodiments are included in the detailed description and 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. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Thus, in some embodiments, well known process steps, well known device structures and well known techniques are not described in detail in order to avoid obscuring the present invention. Like reference numerals refer to like elements throughout.

The spatially relative terms below, beneath, lower, above, upper, etc. may be used to easily describe the correlation of one component with another as shown in the figures. Can be. Spatially relative terms are to be understood as including terms that differ in the direction of use of the components in use or operation in addition to the directions shown in the figures. For example, when inverting the components shown in the figures, components described as beneath beneath other components may be placed above and above other components. Thus, the exemplary term below may include both the direction below and above. The components can be oriented in other directions as well, so that spatially relative terms can be interpreted according to the orientation.

Hereinafter, a diffusion sheet according to an embodiment of the present invention will be described with reference to FIGS. 1A to 1C. 1A is a plan view of a diffusion sheet according to an embodiment of the present invention, respectively, FIG. 1B is a cross-sectional view taken along the line BB ′ of FIG. 1A, and FIG. 1C is a perspective view of the diffusion sheet according to an embodiment of the present invention. .

As shown in FIGS. 1A to 1C, the diffusion sheet 100 according to an embodiment of the present invention includes a transparent substrate 10 and a plurality of diffusion patterns 20. The transparent substrate 10 and the diffusion pattern 20 may be formed separately or may be formed integrally, although not shown. Hereinafter, a case in which the transparent substrate 10 and the diffusion pattern 20 are formed separately will be described. .

First, the transparent substrate 10 is a plate-shaped material made of a transparent material that can transmit light, for example, polycarbonate (poly carbonate), poly sulfone (poly sulfone), poly acrylate (poly acrylate), Polystyrene (poly styrene), poly vinyl chloride (poly vinyl chloride), polyvinyl alcohol (poly vinyl alcohol), poly norbornene (poly norbornene) can be made of a polyester (poly ester) series.

The thickness of the transparent substrate 10 may be, for example, 10 to 1000 μm, and preferably 25 to 600 μm. The transparent substrate 10 is excellent in mechanical strength and thermal stability in the thickness range as described above, can be provided with appropriate flexibility, and there is little loss of transmitted light.

On one surface of the transparent substrate 10, a plurality of diffusion patterns 20 for diffusing light are arranged. The diffusion patterns 20 are arranged in a predetermined column, and each of these columns DA ₁ , DA ₂ , DA ₃ ,..., DA _{n -1} , DA _n constitutes a diffusion array DA. The diffusion patterns 20 included in the diffusion array DA form a three-dimensional shape. For example, the diffusion pattern 20 may be at least one selected from a hemispherical shape, a triangular pyramid shape, a quadrangular pyramid shape, and an aspherical shape, although not shown.

The size of the diameter of the diffusion patterns 20 included in the diffusion array DA depends on where the diffusion array DA is located on the transparent substrate 10. Depending on the position of the diffusion array DA, the diameter of the diffusion patterns 20 included therein may be gradually increased or decreased. For example, the size of the diameter of the diffusion patterns 20 included in the diffusion array DA ₁ positioned at one end of the transparent substrate 10 is relatively large among the diffusion patterns 20 positioned on the transparent substrate 10. It may have the smallest diameter, the size of the diameter of the diffusion pattern 20 included in the diffusion array DA may gradually increase toward the other end side of the transparent substrate 10, the other end of the transparent substrate 10 The diameter of the diffusion patterns 20 included in the diffusion array DA _n positioned at may have the size of the largest diameter among the diffusion patterns 20 positioned on the transparent substrate 10.

The diameter of the diffusion patterns 20 included in the diffusion array DA may be selected, for example, within a range of about 30 to 80 μm, preferably about 40 to 60 μm, and the same diffusion array DA The size of the diameter of the diffusion patterns 20 included in) may have a diameter of substantially the same diameter.

In addition, the height of the diffusion patterns 20 included in the diffusion array DA, that is, the height corresponding to the highest peak from the surface where the diffusion patterns 20 are in contact with the transparent substrate 10 may be the diffusion pattern 20 as described above. It may have a value corresponding to about 50% or less of the diameter of. When the diameter of the diffusion pattern 20 is selected within the range of, for example, about 30 to 80 μm, preferably about 40 to 60 μm, the height of the diffusion pattern 20 is, for example, 15 to 40 μm, Preferably it may be selected in the range of 20 to 30㎛. The diffusion pattern 20 satisfying the diameter and the height may have a hemispherical shape, for example.

The diffusion patterns 20 having the diameter and the height as described above can improve the light collection efficiency by improving the luminance in the normal direction, and can maintain an appropriate radius of curvature and thus have excellent luminance and viewing angle characteristics.

In addition, the diffusion patterns 20 may have a light transmittance of at least about 90%, for example, to prevent the amount of light passing through the diffusion patterns 20 from being lowered. It may have a refractive index in the range of, for example, 1.45 to 1.60 so as not to degrade.

Examples of the material satisfying the above-described requirements of the diffusion patterns 20 include thermosetting resins such as acrylic resins, urethane resins, polyester resins, and the like, and preferably epoxy acrylate resins and urethane acrylic resins. And ultraviolet curing resins such as silicone acrylate resins. The haze of the diffusion pattern 20 made of such a material may be about 80% or more.

The diffusion sheet 100 according to an embodiment of the present invention may be applied when the amount of light reaching one end of the diffusion sheet 100 is greater than the amount of light reaching the other end of the diffusion sheet 100. That is, the size of the diameter of the diffusion patterns 20 included in the diffusion array DA ₁ at _one end of the diffusion sheet 100 is relatively small, and the diffusion included in the diffusion array DA ₂ at the other end of the diffusion sheet. Since the diameters of the patterns 20 are relatively large, the density per unit area of the diffusion pattern 20 in the diffusion array DA ₁ positioned at one end of the diffusion sheet 100 is relatively high, and at the other end. Increasingly, since the density per unit area of the diffusion pattern 20 in the diffusion array DA is relatively low, the light passing through the diffusion sheet 100 is efficiently distributed to uniformly diffuse the light.

Subsequently, a diffusion sheet according to another embodiment of the present invention will be described with reference to FIGS. 2A to 2C. Figure 2a is a plan view of a diffusion sheet according to another embodiment of the present invention, Figure 2b is a cross-sectional view taken along the line BB 'of Figure 2a, Figure 2c is a perspective view of a diffusion sheet according to another embodiment of the present invention to be.

Diffusion sheet according to another embodiment of the present invention is a diffusion sheet (100 in Figs. 1a to 1c) and the seal according to an embodiment of the present invention except for the diffusion pattern 21 in the diffusion array disposed on the transparent substrate Since they are the same, the diffusion sheet 110 according to another embodiment of the present invention will be described based on the differences from the diffusion sheet (100 of FIGS. 1A to 1C) according to an embodiment of the present invention.

As shown in FIGS. 2A to 2C, the diffusion sheet 110 according to another embodiment of the present invention includes a transparent substrate 11 and a plurality of diffusion patterns 21. The diffusion patterns 21 are arranged in a predetermined row to form a diffusion array DA.

The size of the diameter of the diffusion patterns 20 included in the diffusion array DA depends on where the diffusion array DA is located on the transparent substrate 11. Depending on the position of the diffusion array DA, the diameter of the diffusion patterns 21 included in the diffusion array DA may gradually increase or decrease in size. For example, the size of the diameter of the diffusion patterns 21 included in the diffusion arrays DA ₁ and DA _N positioned at both ends of the transparent substrate 11 is located on the transparent substrate 11. Among them, the diameter of the diffusion pattern 20 included in the diffusion array DA may gradually increase in size toward the center of the transparent substrate 11, and the size of the transparent substrate 11 may be increased. The size of the diameters of the diffusion patterns 21 included in the diffusion array DA _m positioned at the center of 11) is the largest of the diffusion patterns 21 positioned on the transparent substrate 11. Can have

The diameter of the diffusion patterns 21 included in the diffusion array DA may be selected within a range of, for example, a diameter of about 30 to 80 μm, preferably about 40 to 60 μm, and included in the same diffusion array. The diameters of the diffusion patterns 21 may be substantially the same diameters.

In addition, the height of the diffusion patterns 21 included in the diffusion array DA may have a value corresponding to about 50% or less of the diameter of the diffusion pattern 20 as described above. When the diameter of the diffusion pattern 21 is selected within the range of, for example, about 30 to 80 mu m, preferably about 40 to 60 mu m, the height of the diffusion pattern is for example 15 to 40 mu m, preferably It may be selected in the range of 20 to 30㎛. The diffusion pattern 21 satisfying the diameter and the height may have a hemispherical shape, for example.

The diffusion patterns 21 having the diameter and the height as described above can improve the condensing efficiency by improving the luminance in the normal direction, and can maintain an appropriate radius of curvature and thus have excellent luminance and viewing angle characteristics.

In addition, the diffusion patterns 21 may have, for example, a light transmittance of about 90% to prevent the amount of light passing through the diffusion patterns 21 from decreasing. It may have a refractive index in the range of, for example, 1.45 to 1.60 so as not to degrade.

Examples of the material satisfying the above-described requirements of the diffusion patterns 21 include thermosetting resins such as acrylic resins, urethane resins, polyester resins, and the like, and preferably epoxy acrylate resins and urethane acrylic resins. And ultraviolet curing resins such as silicone acrylate resins. The haze of the diffusion pattern 22 made of such a material may be about 80% or more.

The diffusion sheet 110 according to another embodiment of the present invention may be applied when the amount of light reaching both ends of the diffusion sheet 110 is greater than the amount of light reaching the other end of the diffusion sheet 110. That is, the diameters of the diffusion patterns 21 included in the diffusion arrays DA ₁ and DA _N at both ends of the diffusion sheet 110 are relatively small, and the diffusion array DA at the center of the diffusion sheet 110 is relatively small. _m ) the unit area of the diffusion pattern 21 in the diffusion arrays DA ₁ and DA _n positioned at both ends of the diffusion sheet 110 is relatively large in diameter of the diffusion patterns 21 included in _m ). Since the sugar density is relatively high and the density per unit area of the diffusion pattern 21 in the diffusion array DA decreases toward the center, the light passing through the diffusion sheet 110 is efficiently distributed to uniform the light. To spread.

Next, a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to FIG. 3. 3 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

As shown in FIG. 3, the liquid crystal display 200 according to the exemplary embodiment of the present invention includes a backlight assembly 210, a liquid crystal display panel 220, upper and lower storage containers 230 and 240, and an intermediate mold frame 250. ), A lower mold frame 260, front and back covers 280 and 290, and the like.

First, the backlight assembly 210 will be described with reference to FIGS. 3 and 4. 4 is a cross-sectional view of a backlight assembly according to an exemplary embodiment of the present invention.

In the backlight assembly 210 according to the exemplary embodiment, the light source 212 is disposed on a side surface of the light guide plate 211, and a light guide plate reflects and diffuses one surface of the light guide plate 211 to multi-reflect light. It may be an edge light type. The backlight assembly 210 includes a light guide plate 211, a light source 212, a diffusion sheet 100, a reflection plate 213, prism sheets 214 and 215, and a protective sheet 216.

The light guide plate 211 guides the light supplied from the light source to the liquid crystal display panel 220. The light guide plate 211 may have a wedge shape in which the thickness of the light guide plate becomes thinner from one end to the other end thereof, that is, the thickness becomes thinner as the light guide plate moves away from the light incident surface.

The light guide plate 211 is made of a material having excellent light transmittance, such as polymethyl methacrylate (PMMA), polycarbonate (PC), cycloolefin-based resin material, the lower surface of the light guide plate 211 inside the light guide plate 211 Various patterns for switching the advancing direction of the incident light to the liquid crystal display panel side are printed and formed.

The light source 212 may be, for example, located on one side of the light guide plate 211, for example, on the side of the wedge-shaped light guide plate 211, and has a thick cylindrical cold cathode fluorescent lamp (Cold Cathode Fluorescent). Lamp; CCFL).

The diffusion sheet 100 is positioned above the light source 212 to diffuse the light emitted through the light guide plate 211 to improve the brightness uniformity of the light. The diffusion sheet 100 includes a plurality of diffusion arrays DA including a transparent substrate 10 facing the light source 212 and a plurality of diffusion patterns 20 having a three-dimensional shape on the transparent substrate 10. do. In this case, the diameters of the diffusion patterns 20 included in the diffusion array DA are gradually changed according to the position of the diffusion array DA. That is, the diffusion pattern 20 is positioned on the transparent substrate 10 in the diffusion array DA ₁ positioned at one end of the transparent substrate 10 corresponding to the side where the light source 212 is located. Among them, the diameter of the diffusion patterns 20 in the diffusion array DA may gradually increase in size toward the other end having a relatively small diameter and far from the light source. That is, the density per unit area of the diffusion patterns 20 in the diffusion array DA ₁ is relatively high on the light-rich side, and the density per unit area of the diffusion patterns 20 in the diffusion array DA _n is low on the side where the light quantity is low. Relatively small, the light passing through the diffusion sheet 100 is efficiently distributed so that the light is uniformly diffused. Since the detailed description of the diffusion sheet 100 is the same as described above, overlapping description is omitted here.

The reflection plate 213 is disposed on the rear surface of the light guide plate 211 and reflects light emitted to the rear surface of the light guide plate 211 toward the upper surface side of the light guide plate 211. The reflective plate 213 reduces the loss of light incident on the liquid crystal display panel 220 and improves the uniformity of light transmitted to the upper surface of the light guide plate 211.

The prism sheets 214 and 215 positioned on the upper part of the diffusion sheet 100 are formed with a regular array of triangular prism on the upper surface, and are generally composed of two sheets so that each prism array is predetermined with each other. The light beams are arranged to be staggered at an angle to collect light diffused from the diffusion sheet 100 in a direction perpendicular to the liquid crystal display panel 220.

The protective sheet 216 positioned on the prism sheets 214 and 215 may serve to protect the surfaces of the prism sheets 214 and 215 and to diffuse the light in order to uniformize the light distribution. .

Referring to FIG. 3 again, the liquid crystal display panel 220 displaying an image is positioned on the backlight assembly 210 having the above-described configuration. The liquid crystal display panel 220 includes a first display panel 221 including a color filter which allows light provided from the backlight assembly 210 to be expressed in a predetermined color by red, green, and blue pixels surrounded by a black matrix, The display panel includes a second display panel 222 including a thin film transistor in a matrix array, and a liquid crystal layer (not shown) formed between the first display panel 221 and the second display panel 222.

The liquid crystal display panel 220 includes data and gate printed circuit boards 215 and 216 in addition to the first display panel 221 and the second display panel 222. The data and gate printed circuit boards 215 and 216 are connected to the liquid crystal display panel 220 by data and gate tape carrier packages 213 and 214 which are a type of flexible circuit board. In operation 216, a driving signal and a timing signal are applied to the gate line and the data line of the thin film transistor in order to control the arrangement angle of the liquid crystal constituting the liquid crystal layer and the timing when the liquid crystal is arranged.

The upper accommodating container 230 fixes the liquid crystal display panel 220 by combining the intermediate mold frame 250 provided on the upper side of the lower accommodating container 240 with a coupling means such as a screw and a plurality of coupling windows on the sidewalls. (Not shown).

The lower storage container 240 is a container for storing the backlight assembly 210, and may have a shape in which the backlight assembly 210 may be seated, for example, a quadrangular shape, and is disposed on the rear surface of the lower storage container 240. Screw grooves (not shown) are formed.

The lower mold frame 260 accommodates the lower accommodating container 240, and a coupling protrusion that hooks a coupling window (not shown) formed on the upper accommodating container 230 to a sidewall of the lower mold frame 260. (Not shown) are provided in plural.

The printed circuit board cover 270 is grounded to the lower housing container 240 by a coupling means such as a screw to block shorts and electromagnetic waves generated on the data printed circuit board 215.

Subsequently, a liquid crystal display according to another exemplary embodiment of the present invention will be described with reference to FIG. 5. 5 is an exploded perspective view of a liquid crystal display according to another exemplary embodiment of the present invention.

As shown in FIG. 5, the liquid crystal display 200 ′ according to another exemplary embodiment of the present invention may include a backlight assembly 210 ′, a liquid crystal display panel 220, upper and lower storage containers 230 and 240, and an intermediate mold frame. 250, a lower mold frame 260, and front and back covers 280 and 290.

Since the liquid crystal display 200 'according to another exemplary embodiment of the present invention is substantially the same as the liquid crystal display according to the exemplary embodiment of the present invention except for the backlight assembly 210', FIGS. A liquid crystal display 200 ′ according to another exemplary embodiment of the present invention will be described with reference to the backlight assembly 210 ′. 6 is a cross-sectional view of a backlight assembly according to another embodiment of the present invention.

First, as shown in FIG. 6, the backlight assembly 210 includes a light guide plate 211 ′, a light source 212 ′, a diffusion sheet 110, a reflector 213, a prism sheet 214, 215, and a protective sheet ( 216).

The light guide plate 211 ′ guides the light supplied from the light source 212 ′ to the liquid crystal display panel 220, and may have a flat shape having a substantially rectangular cross section.

The light guide plate 211 ′ is made of a material having excellent light transmittance, such as polymethyl methacrylate (PMMA), polycarbonate (PC), and cycloolefin-based resin material, and the light guide plate 211 is provided on the lower surface of the light guide plate 211 ′. ') Various patterns for switching the traveling direction of the light incident into the liquid crystal display panel side are printed and formed.

The light source 212 ′ may be located at both sides of the light guide plate 211 ′, for example, and may be formed of a long cylindrical cold cathode fluorescent lamp (CCFL).

The diffusion sheet 110 is positioned above the light source 212 ′ and diffuses the light emitted through the light guide plate 211 ′ to improve luminance uniformity of the light. The diffusion sheet 110 is positioned above the light source 212 to diffuse the light emitted through the light guide plate 211 ′ to improve brightness uniformity of the light. The diffusion sheet 110 may include a plurality of diffusion arrays DA including a transparent substrate 11 facing the light source 212 ′ and a plurality of diffusion patterns 21 having a three-dimensional shape on the transparent substrate 11. Equipped. In this case, the diameters of the diffusion patterns 21 included in the diffusion array DA gradually change according to the position of the diffusion array DA. That is, the diffusion pattern 21 is positioned on the transparent substrate 10 in the diffusion arrays DA ₁ and DA _N positioned at both ends of the transparent substrate 11 corresponding to the side where the light source 212 ′ is located. The diameter of the diffusion patterns 20 may have a diameter of the smallest diameter among the diffusion patterns 20, and the diameter of the diffusion patterns 21 in the diffusion array DA may gradually increase toward the center away from the light source 212 ′. . That is, the density per unit area of the diffusion patterns 21 in the diffusion arrays DA ₁ and DA _n is relatively high on the light-rich side, and the unit areas of the diffusion patterns 21 in the diffusion array DA _m are on the side where the light quantity is low. The sugar density is relatively small to efficiently distribute the light passing through the diffusion sheet 110 so that the light is uniformly diffused. Since the detailed description of the diffusion sheet 110 is the same as described above, the overlapping description is omitted here.

In addition, since the reflective plate 213, the prism sheets 214 and 215, and the protective sheet 216 are also substantially the same as those of the backlight assembly 210 of FIG. Omit.

Hereinafter, the present invention will be described in more detail with reference to experimental and comparative examples. However, the following experimental examples are for illustrating the present invention, it should be understood that the present invention is not limited by the following experimental examples.

Experimental Example  One

A sheet having a plurality of diffusion arrays including a plurality of diffusion patterns made of a urethane acrylate material (manufactured by BASF Corporation) on a transparent substrate (manufactured by Toray Corporation, XU42) of polyester material having a size of 300 × 300 mm was prepared.

At this time, the diameter of the diffusion pattern included in the diffusion array located at one end of the diffusion sheet is 40㎛, the height is 20㎛, the diameter of the diffusion pattern included in the diffusion array located at the other end of the diffusion sheet is 60㎛, 30 μm, the diameter of the diffusion pattern included in the diffusion array positioned between one end and the other end of the diffusion pattern is gradually changed to 1% or less with respect to the diffusion pattern size of the adjacent diffusion array so as to go from one end to the other end of the diffusion pattern. Gradually, the diameter was made larger.

The haze of the diffusion pattern in the finished diffusion sheet was about 90%.

These diffusion sheets were placed one by one on the wedge-shaped light guide plate of the backlight assembly of the liquid crystal display device, and the luminance and viewing angle at the center of the backlight assembly were measured using a luminance meter (BM-7, Topcon, Japan). The result is shown in FIG. 7A.

Experimental Example  2

A sheet having a plurality of diffusion arrays including a plurality of diffusion patterns made of a urethane acrylate material (manufactured by BASF Corporation) on a transparent substrate (manufactured by Toray Corporation, XU42) of polyester material having a size of 300 × 300 mm was prepared.

At this time, the diameter of the diffusion pattern included in each of the diffusion array located at both ends of the diffusion sheet is 40㎛, the height is 20㎛, the diameter of the diffusion pattern included in the diffusion array located at the center of the diffusion sheet is 60㎛, The height is (30) μm, and the diameter of the diffusion pattern included in the diffusion array located between the centers at both ends of the diffusion pattern is gradually changed to 1% or less with respect to the diffusion pattern size of the adjacent diffusion array, so that both ends of the diffusion pattern The diameter gradually increased toward the center.

The haze of the diffusion pattern in the finished diffusion sheet was about 90%.

These diffusion sheets were placed one by one on the flat light guide plate of the backlight assembly of the liquid crystal display device, and the luminance and viewing angle at the center of the backlight assembly were measured using a luminance meter (BM-7, Topcon, Japan). The result is shown in FIG. 7B.

Comparative example  One

Diffusion of 20 μm diameter on a transparent substrate (manufactured by Toray Corporation, XU42) made of polyester of 300 × 300 mm and dispersed at 200 parts by weight relative to 100 round beads (manufactured by Nippon Polyurethane) made of polymethyl methacrylate Sheets were prepared.

The brightness and viewing angles of the diffusion sheet were measured in the same manner as in Experimental Example 1 and Experimental Example 2, respectively, and the results are shown in FIGS. 7A and 7B.

Comparative example  2

A diffusion sheet having a diameter of 15 μm, a height of 7 μm, and a diffusion pattern made of a urethane acrylate material (manufactured by BASF) is arranged on a transparent substrate (manufactured by Toray Corporation, XU42) of 300 × 300 mm size. Prepared. At this time, the diffusion pattern arranged on the transparent substrate has a uniform arrangement.

The haze of the diffusion pattern in the finished diffusion sheet was about 65%.

The brightness and viewing angles of the diffusion sheet were measured in the same manner as in Experimental Example 1 and Experimental Example 2, respectively, and the results are shown in FIGS. 7A and 7B.

Comparative example  3

A diffusion sheet having a diameter of 100 µm, a height of 50 µm, and a diffusion pattern made of an epoxy acrylate material (manufactured by BASF Corporation) on a transparent substrate (manufactured by Teijin Dupont) of 300 x 300 µm in size. Was prepared. At this time, the diffusion pattern arranged on the transparent substrate has a uniform arrangement.

The haze of the diffusion pattern in the finished diffusion sheet was about 75%.

The luminance and viewing angles of the diffusion sheet were measured in the same manner as in Experimental Example 1 and Experimental Example 2, respectively, and the results are shown in FIGS. 7A and 7B.

7A and 7B, when comparing the results of luminance and viewing angles measured at the centers of the diffusion sheets of Experimental Examples 1 and 2 and the diffusion sheets of Comparative Examples 1 to 3 according to the embodiments of the present invention, Diffusion sheet of Comparative Example 1, wherein the luminance and viewing angle at the center of the diffusion sheets of Experimental Examples 1 and 2, in which the diffusion pattern included in the diffusion pattern gradually changes depending on the position of the diffusion array, includes diffusion beads, It can be seen that about 3 to 10% improvement over the diffusion sheets of Comparative Examples 2 and 3 including the diffusion pattern having a diameter. In Comparative Example 1, the distribution of the diffusion beads is not regular, and the diffusion beads are aggregated with each other to reduce light diffusion efficiency, and in Comparative Examples 2 and 3, the diameter of the diffusion pattern is too small or too large, and the haze Not enough, light diffusion efficiency is low.

As described above, the backlight assembly and the liquid crystal display including the diffusion sheets according to the exemplary embodiments of the present invention include a diffusion pattern in which a diffusion pattern included in the diffusion array gradually changes in size depending on the position of the diffusion array. And the viewing angle can be further improved.

Although 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 may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

According to the diffusion sheet according to the present invention as described above, the backlight assembly and the liquid crystal display including the same, the viewing angle of the liquid crystal display by including a diffusion pattern whose diameter varies according to the position of the diffusion array in the diffusion sheet; The luminance characteristic can be improved at the same time.

Claims (13)

Transparent substrates; And A plurality of diffusion array including a plurality of diffusion patterns having a three-dimensional shape on the transparent substrate, The diffusion pattern included in the diffusion array is gradually changed in size in accordance with the position of the diffusion array, The diffusion pattern is at least one selected from hemispherical, triangular pyramid, square pyramidal and non-spherical. The method of claim 1, And the diffusion pattern gradually increases in diameter from the diffusion array positioned at one end of the transparent substrate to the diffusion array positioned at the other end of the transparent substrate. The method of claim 1, And the diffusion pattern gradually increases in diameter from the diffusion array positioned at both ends of the transparent substrate to the diffusion array positioned at the center of the transparent substrate. The method of claim 1, The diffusion pattern is a diffusion sheet having a diameter of 30 to 80㎛. The method of claim 4, wherein The height of the diffusion pattern is a diffusion sheet having a value corresponding to 50% or less of the diameter of the diffusion pattern. delete Light guide plate; A light source positioned on at least one side of the light guide plate; And A plurality of diffusion arrays including a transparent substrate facing the light guide plate and a plurality of diffusion patterns having a three-dimensional shape on the transparent substrate, And the diffusion pattern included in the diffusion array includes a diffusion sheet whose diameter gradually changes depending on a position of the diffusion array. The method of claim 7, wherein The light source is positioned on one side of the light guide plate, and the diffusion pattern is gradually increased in size from the diffusion array positioned at one end of the transparent substrate corresponding to the light source to the diffusion array positioned at the other end of the transparent substrate. Backlit assembly. The method of claim 7, wherein The light sources are respectively located at both sides of the light guide plate, and the diffusion pattern is gradually increased from the diffusion array positioned at both ends of the transparent substrate respectively corresponding to the light source to the diffusion array positioned at the center of the transparent substrate. The backlight assembly gradually increases in size. The method of claim 7, wherein The diffusion pattern is 30 to 80㎛ backlight assembly. The method of claim 10, The height of the diffusion pattern has a value corresponding to 50% or less of the diameter of the diffusion pattern. The method of claim 7, wherein The diffusion pattern is at least one selected from hemispherical, triangular pyramid, square pyramidal and non-spherical. A liquid crystal display device comprising a backlight assembly according to any one of claims 7 to 12.

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