KR100806133B1 - Diffuse sheet and backlight assembly and liquid crystal display comprising the same - Google Patents

Abstract

A diffuse sheet, and a backlight assembly and a liquid crystal display including the same are provided to improve a visible angle of a brightness characteristic of the liquid crystal display by including a diffuse pattern provided with a predetermined gradation array on the diffuse sheet. A diffuse sheet(100) includes a transparent substrate(10) and a plurality of diffuse patterns(20). The transparent substrate has a plate shape made of a transparent material. A thickness of the transparent substrate is in a range of 10 to 1000 micrometers and preferably is in a range of 25 to 600 micrometers. The transparent substrate has mechanical strength and thermal stability. The transparent substrate has proper flexibility. The diffuse patterns for diffusing light are arranged on one surface of the transparent substrate. A top surface of the diffuse pattern has a round surface shape. Diameters of the diffuse patterns are in a range of 30 to 80 micrometers and preferably are in a range of approximately 40 to 60 micrometers. The diffuse patterns positioned on the transparent substrate substantially have the same diameter.

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 above technical problem is located on the transparent substrate, and the upper surface, the light is diffused to include a plurality of diffusion patterns are spherical, the diffusion The pattern has a predetermined gradient arrangement in which the density per unit area gradually changes on the transparent substrate.

The gradation array may be arranged such that the density per unit area of the diffusion pattern on the transparent substrate is gradually lowered from one end to the other end of the transparent substrate.

In addition, the gradation array may be arranged such that the density per unit area of the diffusion pattern on the transparent substrate gradually decreases from both ends of the transparent substrate toward the center.

The diameter of the diffusion pattern may be about 30 to 80㎛, preferably about 40 to 60㎛.

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 comprising: a light guide plate, a light source positioned on one side of the light guide plate or on both sides of the light guide plate, and a transparent substrate facing the light guide plate; The upper surface of the light diffusing pattern includes a plurality of diffusion patterns, each of which is spherical, wherein the diffusion pattern has a gradation arrangement in which the density per unit area is gradually changed on the transparent substrate.

The light source may be positioned on one side of the light guide plate, and the gradation array may be arranged such that the density per unit area of the diffusion pattern on the transparent substrate gradually decreases from one end of the transparent substrate corresponding to the light source to the other end. .

In addition, the light sources are respectively located at both sides of the light guide plate, and the gradation arrangement gradually decreases the density per unit area of the diffusion pattern on the transparent substrate toward the center from both ends of the transparent substrate corresponding to the light source, respectively. Can be arranged to

The diffusion pattern may have a diameter of about 30 to 80 μm, preferably about 40 to 60 μm.

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 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. 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 directions 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 view of the diffusion sheet according to an embodiment of the present invention. Perspective view.

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.

A plurality of diffusion patterns 20 for diffusing light are disposed on one surface of the transparent substrate 10. The diffusion pattern 20 has a spherical shape in which an upper surface to which light is diffused is spherical. In addition, the diffusion pattern 20 may have a diameter of, for example, about 30 to 80 μm, preferably about 40 to 60 μm, and the plurality of diffusion patterns 20 positioned on the transparent substrate 10 may be substantially It can have the same diameter size with each other.

In addition, the height of the diffusion pattern 20, that is, the upper surface from which light is diffused, the height corresponding to the highest peak from the surface in contact with the transparent substrate 10 of the diffusion pattern 20 having the spherical shape is as described above. The diffusion pattern 20 may have a value corresponding to about 50% or less of the diameter. The height of the diffusion pattern 20 may be, for example, 15 to 40 μm, preferably 20 to 30 μm. The diffusion pattern 20 satisfying the diameter and the height may have a hemispherical shape, for example.

The diffusion pattern 20 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, thereby having excellent luminance and viewing angle characteristics.

In addition, in order to prevent the amount of light passing through the diffusion pattern 20 from decreasing, the diffusion pattern 20 may have, for example, a light transmittance of about 90% or more, and the luminance and the viewing angle may be reduced by the diffusion pattern 20. So as not to have a refractive index in the range of, for example, 1.45 to 1.60.

Examples of the material satisfying the above-described requirements of the diffusion pattern 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 pattern 20 is arranged on the transparent substrate 10 in a predetermined form. The diffusion pattern 20 is a gradation in which the number of diffusion patterns 20 positioned per unit area of the transparent substrate 10, that is, the density per unit area of the diffusion pattern 20 on the transparent substrate 10 varies gradually. Has an array For example, the diffusion pattern 20 may have a gradient arrangement in which the density per unit area of the diffusion pattern 20 on the transparent substrate 10 gradually decreases from one end of the transparent substrate 10 to the other end.

When the diffusion pattern 20 has the gradation arrangement as described above, it can 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 diffusion pattern 20 is arranged at a relatively high density at one end of the diffusion sheet 100, and the diffusion pattern 20 is arranged at a relatively low density toward the other end, and passes through the diffusion sheet 100. The light is distributed efficiently so that the light is uniformly diffused.

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. .

As shown in Figure 2a to 2c, the diffusion sheet 110 according to another embodiment of the present invention is one embodiment of the present invention except for the arrangement of the diffusion pattern 21 disposed on the transparent substrate 10 Since the diffusion sheet (100 of FIGS. 1A to 1C) according to an example is substantially the same, another embodiment of the present invention focuses on the difference from the diffusion sheet (100 of FIGS. 1A to 1C) according to an embodiment of the present invention. The diffusion sheet 110 according to the example will be described.

In the diffusion sheet 110 according to another embodiment of the present invention, a plurality of diffusion patterns 21 are arranged on a transparent substrate 10 in a predetermined form. That is, the diffusion pattern 21 may have a predetermined gradation arrangement on the transparent substrate 10. For example, the diffusion pattern 21 may have a gradient arrangement in which the density per unit area of the diffusion pattern 21 on the transparent substrate 10 gradually decreases from both ends of the transparent substrate 10 toward the center.

When the diffusion pattern 20 has the gradation arrangement as described above, it can be applied when the amount of light reaching both ends of the diffusion sheet 110 is relatively larger than the amount of light reaching the center. That is, the diffusion pattern 21 is arranged at a relatively low density at the central portion of the diffusion sheet 110, and the diffusion pattern 21 is arranged at a relatively high density toward both ends, so that the diffusion sheet 110 is formed. The light passing through is efficiently distributed so that the light is uniformly diffused.

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 illustrated in FIG. 3, the liquid crystal display 200 according to the 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, 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 located at, for example, one side of the light guide plate 211, for example, a thick side surface of the wedge-shaped light guide plate 211, and has a long and cold 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 is located on the transparent substrate 10 and the transparent substrate 10 facing the light source 212, the upper surface to which the light is diffused has a spherical surface, 30 to 80㎛, preferably It includes a plurality of diffusion patterns 20 having a diameter of 40 to 60㎛. The height of the diffusion pattern 20 may have, for example, a value corresponding to 50% or less of the diameter of the diffusion pattern, for example, 15 to 40 μm, preferably 20 to 30 μm. The diffusion pattern 20 may have a hemispherical shape, for example.

At this time, the diffusion pattern 20 has a predetermined gradation arrangement on the transparent substrate 10, for example, the diffusion on the transparent substrate toward the other end from one end of the transparent substrate 10 corresponding to the side where the light source 212 is located It may have a gradation arrangement in which the density per unit area of the pattern 20 is gradually lowered. That is, the density of the diffusion pattern 20 is relatively high on the light-rich side, and the density of the diffusion pattern 20 is relatively low on the side of the light quantity, thereby efficiently distributing the light passing through the diffusion sheet 100 so that the light is uniform. To spread.

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 225 and 226 in addition to the first display panel 221 and the second display panel 222. The data and gate printed circuit boards 225 and 226 are connected to the liquid crystal display panel 220 by data and gate tape carrier packages 223 and 224, which are a type of flexible circuit board, and the data and gate printed circuit boards 225 and 226. In operation 226, 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 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 225.

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 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, and front and back covers 280 and 290.

Since the liquid crystal display according to another exemplary embodiment of the present invention is substantially the same as the liquid crystal display according to the exemplary embodiment except for the backlight assembly 210 ′, the backlight assembly is described with reference to FIGS. 5 and 6. A liquid crystal display 200 'according to another exemplary embodiment of the present invention will be described with reference to 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 plate 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.

For example, the light sources 212 may be positioned at both side surfaces of the light guide plate 211, and may be formed of an elongated 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 on the transparent substrate 10 and the transparent substrate 10 facing the light source 212 ′, and the upper surface through which the light is diffused has a spherical surface, preferably 30 to 80 μm. Includes a plurality of diffusion patterns 21 having a diameter of 40 to 60 mu m. The height of the diffusion pattern 21 may have, for example, a value corresponding to 50% or less of the diameter of the diffusion pattern, for example, 15 to 40 μm, preferably 20 to 30 μm. The diffusion pattern 21 may have a hemispherical shape, for example.

At this time, the diffusion pattern 20 has a predetermined gradation arrangement on the transparent substrate 10, for example, the transparent toward the center at both ends of the transparent substrate 10 corresponding to the side where the light source 212 'is located, respectively. The density per unit area of the diffusion pattern 21 on the substrate may have a gradation arrangement that gradually decreases. In other words, the density of the diffusion pattern 21 is relatively high on the light-rich side, and the density of the diffusion pattern 21 is relatively low on the side of the light quantity, thereby efficiently distributing the light passing through the diffusion sheet 110 to provide light. This spreads uniformly.

In addition, since the reflective plate 213, the prism sheets 214 and 215, and the protective sheet 216 are substantially the same as in the backlight assembly 210 of FIG. 4 according to an embodiment of the present invention, overlapping descriptions will be provided herein. 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

Diffusion having a diameter of 50 μm, a height of 25 μm, and a plurality of diffusion patterns made of urethane acrylate material (manufactured by BASF Corporation) on a transparent substrate (manufactured by Toray Corporation, XU42) of 300 × 300 mm size Sheets were prepared. In this case, the diffusion pattern arranged on the transparent substrate has a gradation array in which the density per unit area of the diffusion pattern gradually decreases from one end of the transparent substrate to the other end. 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

Diffusion having a diameter of 50 μm, a height of 25 μm, and a plurality of diffusion patterns made of urethane acrylate material (manufactured by BASF Corporation) on a transparent substrate (manufactured by Toray Corporation, XU42) of 300 × 300 mm size Sheets were prepared. In this case, the diffusion patterns arranged on the transparent substrate have a gradation array in which the density per unit area of the diffusion pattern gradually decreases from both ends to the center of the transparent substrate. 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 (made 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, in which the luminance and viewing angle at the center of the diffusion sheets of Experimental Examples 1 and 2, in which the diffusion pattern had a predetermined gradation arrangement, included diffusion beads, and diffusion sheets of Comparative Examples 2 and 3, which did not have gradation arrangement It can be seen that about 3 to 5% improvement over these. In Comparative Example 1, the distribution of the diffusion beads is not regular, and the diffusion beads are agglomerated with each other, resulting in poor light diffusion efficiency, and in Comparative Examples 2 and 3, the size of the diffusion pattern is too small or too large, and the haze is not sufficient. The light diffusion efficiency is poor.

As described above, the backlight assembly and the liquid crystal display including the diffusion sheets according to the exemplary embodiments of the present invention may include a diffusion pattern having a predetermined gradation arrangement, thereby further improving luminance and viewing angle.

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, the backlight assembly including the same, and the liquid crystal display according to the present invention as described above, the diffusion sheet includes a diffusion pattern having a predetermined gradation arrangement, thereby simultaneously improving the viewing angle and luminance characteristics of the liquid crystal display. Can be.

Claims (11)

Transparent substrates; And Located on the transparent substrate, including a plurality of diffusion patterns having a spherical upper surface where light is diffused, And the diffusion pattern has a predetermined gradation array in which the density per unit area is gradually changed on the transparent substrate. The method of claim 1, And the gradation array is arranged such that the density per unit area of the diffusion pattern on the transparent substrate is gradually lowered from one end to the other end of the transparent substrate. The method of claim 1, And the gradation array is arranged such that the density per unit area of the diffusion pattern on the transparent substrate gradually decreases from both ends to the center of the transparent substrate. The method of claim 1, The diffusion sheet has a diameter of 30 to 80㎛ diameter of the diffusion pattern. 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. Light guide plate; Light sources positioned on at least one side of the light guide plate or on opposite sides of the light guide plate; And A transparent substrate facing the light guide plate, and a plurality of diffusion patterns positioned on the transparent substrate and having an upper surface thereof, and having a spherical surface, wherein the diffusion patterns have a gradient arrangement in which the density per unit area gradually changes on the transparent substrate. A backlight assembly comprising a diffusion sheet. The method of claim 6, The light source is positioned on one side of the light guide plate, and the gradation array is arranged such that the density per unit area of the diffusion pattern on the transparent substrate gradually decreases from one end of the transparent substrate corresponding to the light source to the other end. . The method of claim 6, The light sources are respectively located at both sides of the light guide plate, and the gradation array of the diffusion sheet has a density per unit area of the diffusion pattern on the transparent substrate gradually toward the center from both ends of the transparent substrate corresponding to the light source, respectively. Backlight assembly arranged to be lowered. The method of claim 6, The diffusion pattern has a diameter of 30 to 80㎛ the backlight assembly. The method of claim 9, The height of the diffusion pattern has a value corresponding to 50% or less of the diameter of the diffusion pattern. A liquid crystal display device comprising a backlight assembly according to any one of claims 6 to 10.

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