WO2009017304A1

WO2009017304A1 - Optical sheet and backlight assembly and liquid crystal display comprising the same

Info

Publication number: WO2009017304A1
Application number: PCT/KR2008/003395
Authority: WO
Inventors: Seung Kyu Choi; Cheol Heung Ahn; Suk Jun Kim; Je Min Yeoun; Young Shin Choi; Chan Kyu Park; Ka Young Son; Hyun Ee Yang
Original assignee: Shinhwa Intertek Corp.
Priority date: 2007-07-31
Filing date: 2008-06-16
Publication date: 2009-02-05
Also published as: CN101784919B; TWI370296B; KR20090012822A; KR100907231B1; CN101784919A; TW200914940A

Abstract

Provided are an optical sheet, and a backlight assembly and a liquid crystal display including the optical sheet. The optical sheet includes a transparent base, and plural three-dimensional pattern layers sequentially disposed on one surface of the transparent base. A single optical sheet has a multi-function of photo refractivity, condensing and light diffusion, and requires neither a masking film nor a protective film to thereby be excellent in cost reduction, productivity and workability. Thus, lighter, thinner, simpler and smaller liquid crystal display can be accomplished.

Description

OPTICAL SHEET AND BACKLIGHT ASSEMBLY AND LIQUID CRYSTAL DISPLAY COMPRISING THE SAME

Technical Field

[1] The present invention is directed to an optical sheet, and a backlight assembly and a liquid crystal display having the same, and more particularly, to an optical sheet that realizes functions of a diffuser sheet, a prism sheet and a protector sheet by a single sheet, and a backlight assembly and a liquid crystal display having the same. Background Art

[2] Liquid crystal displays are one kind of flat panel display apparatuses that display images using electrical and optical characteristics of liquid crystals having an intermediary characteristic of liquid and solid. The liquid crystal displays are thinner and lighter than other display apparatuses, and have a lower driving voltage and lower power dissipation, which thus are widely available in the whole field of industry.

[3] Because a display panel for displaying images is a non light-emitting device which cannot emit light by itself, the liquid crystal display requires a backlight assembly that can supply the light separately.

[4] Generally, a backlight assembly includes a knp unit, a light guide member that guides light from the lamp unit, a diffuser sheet disposed to an upper surface of the light guide member to diffuse the light, a prism sheet for condensing the light outgoing from the diffuser sheet, and a protector sheet for shielding the prism sheet. The number of parts constituting the back light assembly is increased because of the separate installing of the diffuser sheet, the prism sheet and the protector sheet. Due to the increased number of the parts, it is difficult to make the backlight assembly lighter, thinner, simpler and smaller. Furthermore, a number of the assembling processing is increased, which in turn increases an inferior rate to raise overall manufacturing cost. Disclosure of Invention Technical Problem

[5] The present invention provides an optical sheet with a multi-function.

[6] The present invention also provides a backlight assembly including an optical sheet with a multi-function.

[7] The present invention also provides a liquid crystal display including an optical sheet with a multi-function. Advantageous Effects

[8] In the optical sheet, and the backlight assembly and the liquid crystal display having the same according to the present invention as described above, the single optical sheet has the multi-function of the photo refractivity, optical condensing and light diffusion, and requires neither a masking film nor a protective film, thereby being excellent in cost reduction, productivity, and workability while the lighter, thinner, simpler and smaller liquid crystal display can be realized. Brief Description of the Drawings

[9] FIGS. 1 through 4 are sectional views illustrating optical sheets according to an embodiment of the present invention;

[10] FIGS. 5 through 8 are sectional views illustrating optical sheets according to another embodiment of the present invention; and

[11] FIG. 9 is an exploded perspective view illustrating a liquid crystal display according to an embodiment of the present invention. Best Mode for Carrying Out the Invention

[12] According to an embodiment of the present invention, there is provided an optical sheet comprising: a transparent base; and a plurality of three-dimensional pattern layers sequentially disposed on one surface of the transparent base. The optical sheet further comprises: functional beads interposed between the transparent base; and a three-dimensional pattern layer disposed on the lowest place of the plurality of three- dimensional pattern layers. Also, the optical sheet comprises a predetermined surface roughness at the top of a three-dimensional pattern layer disposed on the uppermost place of the plurality of three-dimensional pattern layers.

[13] Furthermore, in the optical sheet, the uppermost three-dimensional pattern layer out of the plurality of three-dimensional pattern layers comprises silicon acrykte. Also, the plurality of three-dimensional pattern layers have a refractive index increased when reaching from the lower portion toward the upper portion.

[14] According to another embodiment of the present invention, there is provided an optical sheet comprising: a transparent base; a first three-dimensional pattern layer disposed on one side of the transparent base; and a second three-dimensional pattern layer disposed on the first three-dimensional pattern layer.

[15] At this time, the first three-dimensional pattern layer may be shaped as embossing, and the second three-dimensional pattern layer comprises at least one pattern selected from a prism pattern, a lenticular pattern, a micro lens pattern, and a Fresnel pattern. [16] Also, the second three-dimensional pattern layer comprises a predetermined surface roughness at the top thereof, and the surface roughness ranges from 0.05 to 0.5/M. The second three-dimensional pattern layer may comprise silicon acrykte.

[17] The optical sheet further comprises functional beads between the transparent base and the first three-dimensional pattern layer, and the functional beads may be light diffusion beads.

[18] In the optical sheet, the upper surface of the first three-dimensional pattern layer and the lower surface of the second three-dimensional pattern layer have substantially complementary shape.

[19] According to another embodiment of the present invention, there is provided a backlight assembly comprising: a lamp unit; a light guide member for upward guiding light from the lamp unit; and an optical sheet claimed as above and disposed on an upper surface of the light guide member.

[20] According to still another embodiment of the present invention, there is provided liquid crystal display comprising: a display panel; and a backlight assembly of claim 16 for supplying the light to the display panel. Mode for the Invention

[21] Embodiments of the present invention are described in detail in the detailed description and the accompanying drawings. The advantages and features of the present invention and a method of realizing the present invention will be clarified with reference to embodiments which will now be described more fully with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. The present invention is defined by definitions recited in the claims only. In the specification, like reference numerals in the drawings denote like elements.

[22] Hereinafter, optical sheets according to an embodiment of the present invention will be described with reference to FIGS. 1 through 4.

[23] FIGS. 1 through 4 are sectional views illustrating optical sheets according to an embodiment of the present invention.

[24] In addition to a light diffuser function, and a condensing function of diffracting and concentrating the light to heighten luminance, optical sheets 100, 110, 120 and 130 according to the embodiment of the present invention have a protection function that prevents scratches generated against other members near to the optical sheets 100, 110, 120 and 130.

[25] As illustrated in FIG. 1, the optical sheet 100 may include a transparent base 10 and a plurality of three-dimensional (hereinafter simply referred to as "3D" pattern layers 20 and 30. Preferably, a first 3D pattern layer 20 and a second 3D pattern layer 30 may be provided to one side of the transparent base 10.

[26] First, the transparent base 10 is shaped as a plate formed of a colorless transparent synthetic resin that allows light to be transmitted. The synthetic resin forming the transparent base 10 is not specially limited, but may include polyethylene- terephthalate, polyethylene-naphthalate, acryl resin, polycarbonate, polysthylene, polyolefine, cellous acetate, weather-resistant polyvinyl chloride, for example. Among these materials, polyethylene-terephthalate or polycarbonate with an excellent transparency and a high strength property, and polyethylene-terephthalate with an enhanced warping performance are more preferable.

[27] A thickness of the transparent base 10 is not specially defined, but may be

10~1000/M, and preferably 25-600/M, for example. The transparent base 10 is excellent in a mechanical strength and thermal stability, and has an appropriate flexibility while a loss of transmitted light is small within the above-described thickness range.

[28] The first 3D pattern layer 20 is disposed on the transparent base 10. The first 3D pattern layer 20 functioning by diffusing the light may be rugged by embossing. Protruding portions of the embossing form of the first 3D pattern layer 20 may be diversely shaped as, e.g., a sphere, a rotating ellipsoid, a square pyramid and a fiber, but the present invention is not specially limited to such a shape.

[29] A material constituting the first 3D pattern layer 20 is not restrictively defined, but may be, e.g., acryl resin, polyurethane, polyester, fluoride-based resin, silicon-based resin, polyanideinide, epoxy resin, and ultraviolet curing resin. Thus, one polymer as mentioned above may be used or at least two kinds of them may be nixed. In addition to the polymer, the first 3D pattern layer 20 may further include a fine inorganic or organic filler, a hardener, a plasticizer, various leveling agents, a ultraviolet absorber, an antioxidant, a viscosity modifier, a lubricant, a light stabilizer.

[30] The first 3D pattern layer 20 may have a relatively low refractive index of, e.g., a refractive index of 1.53 or less, and preferably, 1.4-1.51. The first 3D pattern layer 20 has the relatively low refractive index to make a lot of quantity of the light incident from the light guide pkte diffuse upward. [31] Also, the first 3D pattern layer 20 may have an average thickness of about 5~100/M.

By forming the first 3D pattern layer 20 to have the above-stated thickness range, the light can be efficiently condensed in a normal line direction.

[32] Also, as illustrated in FIG. 2, functional beads 15 may be interposed between the transparent base 10 and a surface of the first 3D pattern layer 20. At this time, the interposing of the functional bead 15 between the transparent base 10 and the surface of the first 3D pattern layer 20 includes both cases that the functional beads 15 contact the transparent base 10, and are separated from the transparent base 10 even not illustrated.

[33] The functional bead 15 may be, e.g., a light diffusion bead that reinforces the light diffusion function. When the functional bead 15 is a light diffusion bead, the light transmitted from the transparent base 10 toward the first 3D pattern layer 20 can be evenly diffused.

[34] When the functional bead 15 is the light diffusion bead, the light diffusion bead may be an inorganic filler or an organic filler. The inorganic filler may include, e.g., silica, aluminum hydroxide, aluminum oxide, zinc oxide, barium sulfide, magnesium silicate, calcium carbonate, and titanium oxide, so that one of the inorganic filler described as above may be used or at least two of them are nixed. The organic filler may use mul- tilayered multicomponent-based particles formed by covering a monomer of another kind after forming acryl-based particles of homopolyer or copolymer of, e.g., urethane, nylon, silicon, mekrin-forumaldehyde, benzoguanamine-forumaldehyde, methyl- methacrylate, acrylic acid, methatrile acid, hydroxyethyl-methacrylate, hydroxypropyl- methacrylate, acrykride, methylolacrykride, glycidyl-methacrylate, ethylacrykte, isobutylacrylate, normalbutylacrykte, and 2-ethylhyxylacrylate; olefin-based particles such as polyethylene, polysthylene and polypropylene; and acryl and olefine-based copolymer particles and homopolyer particles.

[35] The above-mentioned inorganic filler or organic filler stated as the light diffusion bead is provided just for illustrative purposes, and may be replaced with another well- known material that can achieve the main object of the present invention without being defined by the inorganic filler or the organic filler, which is obvious to the ordinary skilled in the art.

[36] The functional bead 15 has a particle distribution of both mono dispersion and poly- dispersion, whose shape is not specifically restricted, and may be shaped as a sphere, a spindle, a needle, a rod, a cubic, a plate, a scale, a fiber. Here, the most preferable one is a spherical bead with an excellent light diffusion property. [37] An average diameter of the functional bead 15 may be 1~100/M, and preferably

5-50/M, for example. In the event that the average diameter of the functional bead 15 is within the above-stated range, it has the sufficient diffusion function. Also, when the functional bead may be about 10~500wt%, for example, when the resin used in the first 3D pattern layer 20 is 100wt%.

[38] As illustrated in FIGS. 1 and 2, the second 3D pattern layer 30 is disposed on an upper surface of the first 3D pattern layer 20, which condenses the light to enhance the luminance. A lower surface of the second 3D pattern layer 30 is shaped to substantially complement with an upper surface of the first 3D pattern layer 20, and an upper surface thereof may has various 3D pattern forms.

[39] The second 3D pattern layer 30 may have a series of prism patterns along the upper surface thereof. The prism pattern may be a linearly arranged triangular prism pattern, a quadrangular pyramid prism pattern, or a triangular prism pattern, for example. The second 2D pattern layer 30 of the foregoing prism pattern increases the luminance of the image monitored by an observer through a display apparatus.

[40] As illustrated in FIG. 3, a second 3D pattern layer 40 may have a lenticular pattern or a micro lens pattern on an upper surface thereof. The second 3D pattern layer 40 having the lenticular pattern or the micro lens pattern can simultaneously embody the diffusion function of the diffuser sheet and the condensing function of the prism sheet.

[41] As illustrated in FIG. 4, a second 3D pattern layer 50 may have a Fresnel pattern on an upper surface thereof, which may be provided with 3D patterns of diverse forms in addition to the above-described patterns.

[42] As illustrated in FIGS. 1 through 4, the second 3D pattern layers 30, 40 and 50 may include silicon acrylate, for example. In case of the second 3D pattern layers 30, 40 and 50 including silicon acrylate, a surface friction coefficient is low because of a slip property of silicon itself to afford excellent workability, the surfaces of the second 3D pattern layers 30, 40 and 50 are not damaged even without forming a separate masking film on them.

[43] Moreover, even if a protective film for shielding the second 3D patterns 30, 40 and

50 including silicon acrykte and protecting the display panel disposed on the upper surfaces of the second 3D pattern layers 30, 40 and 50 are not provided on the second 3D pattern layers 30, 40 and 50, a polarizing film of a display panel 220 of FIG. 9 is not damaged.

[44] The second 3D pattern layers 30, 40 and 50 may have a refractive index higher than that of the first 3D pattern layer 20 of, for example, 1.53 and higher and, preferably, 1.54-1.6. If the refractive index of the second 3D pattern layers 30, 40 and 50 is smaller than 1.53, it should be higher than that of the first 3D pattern layer 20. This is because, if the refractive index of the first 3D pattern layer 20 is higher than that of the second 3D pattern layers 30, 40 and 50, a portion of the light incident to a rear side of the first 3D pattern layer 20 is totally reflected from the surfaces of the second 2D pattern layers 30, 40 and 50 not to be incident to the 3D structure of the second 3D pattern layers 30, 40 and 50.

[45] Furthermore, the second 3D patterns 30, 40 and 50 may have an average thickness of about 5~100/M. When the second 3D patterns 30, 40 and 50 have the thickness within the above-mentioned range, the light is efficiently condensed in the normal line direction. Also, although unshown in the drawings, if the second 3D pattern layers 40 and 50 respectively have the upper surfaces with the lenticular pattern, the micro lens pattern or Fresnel pattern, the functional bead 15 may be added between surfaces of the transparent base 10 and the first 3D pattern layer 20.

[46] Also, optical sheets according to another embodiment of the present invention will be described with reference to FIGS. 5 through 8. FIGS. 5 through 8 are sectional views illustrating optical sheets according to another embodiment of the present invention.

[47] The optical sheets 140, 150, 160 and 170 according to this embodiment substantially equal to the optical sheets according to the above-described embodiment of the present invention except for having a predetermined surface roughness on the top of a second 3D pattern layer. Therefore, the optical sheets according to this embodiment of the present invention will be described by concentrating on differences from the optical sheets according to the above-described embodiment of the present invention with reference to FIGS. 1 through 4.

[48] As illustrated in FIG. 5, the optical sheet 140 according to this embodiment of the present invention includes a transparent base 10, a second 3D pattern layer 20 and a second 3D pattern layer 60. Furthermore, a functional bead 15 may be disposed between the transparent base 10 and a surface of the first 3D pattern layer 20 as illustrated in FIG. 6. The transparent base 10, the functional bead 15 and the first 3D pattern layer 20 substantially equal to those of the optical sheet 100 of FIG. 1 according to the above-described embodiment of the present invention. Thus, repeated description will not be provided.

[49] A second 3D pattern layer 60 condensing the light to enhance the luminance is disposed on an upper surface of the first 3D pattern layer 20. A lower surface of the second 3D pattern layer 60 substantially complements to the shape of an upper surface of the first 3D pattern layer 20, and an upper surface thereof may have various 3D patterns with a predetermined surface roughness at the top thereof.

[50] As illustrated in FIGS. 5 and 6, the second 3D pattern layer 60 may have a series of prism patterns with a predetermined surface roughness at the top thereof. The surface roughness may be provided to the top of the second 3D pattern 60 by grinding, for example. The second 3D pattern layer 60 having the prism pattern with the predetermined surface roughness on the upper surface thereof enhances the luminance of images monitored by an observer through a display apparatus.

[51] As illustrated in FIG. 7, a second 3D pattern layer 70 may be provided with a lenticular pattern or a micro lens pattern with a predetermined surface roughness to the top thereof. The second 3D pattern layer 70 provided with the lenticular pattern or the micro lens pattern with the predetermined surface roughness to the top thereof can simultaneously embody the diffusion function as a diffuser sheet and the condensing function as a prism, for example.

[52] As illustrated in FIG. 8, a second 3D pattern layer 70 may have a Fresnel pattern with a predetermined surface roughness on an upper surface thereof, which may be provided with 3D patterns of diverse forms with a predetermined surface roughness in addition to the above-described patterns.

[53] As illustrated in FIGS. 5 through 8, the surface roughness of the second 3D pattern layers 60, 70 and 80 having the various forms of 3D patterns with the predetermined surface roughness on the upper surface has a range of about 0.05-0.5/M, for example. When the second 3D pattern layers 60, 70 and 80 have the above-mentioned surface roughness range, the surfaces can have an excellent condensing force without being damaged by the other adjacent surfaces.

[54] Moreover, a rate of an area of the surface roughness in the second 3D pattern layers

60, 70 and 80 may be, e.g., about 0.01-10% with respect to a total area of the 3D pattern. When the rate of the area with the surface roughness in the second 3D pattern layers 60, 70 and 80 has the above-stated range, the surface with the surface roughness can have the excellent condensing force without being damaged by the other adjacent surfaces.

[55] The light diffusion efficiency can be enhanced by the second 3D pattern layers 60, 70 and 80 with a predetermined surface roughness since the light incident through a rear surface of the transparent base 10 is evenly diffused using the fine ruggedness formed by the surface roughness when being externally discharged through the second 3D pattern layers 60, 70 and 80. [56] Moreover, the second 3D pattern layers 60, 70 and 80 may include silicon acrylate similar to the optical sheet according to the above-described embodiment of the present invention. The second 3D pattern layers 60, 70 and 80 including silicon acrylate are excellent in workability, and have surfaces that are not damaged even without separately attaching a masking film. Also, a polarizing film of a display panel is not damaged even if a protective film for shielding the display panel disposed on an upper surface of the second 3D pattern layers 60, 70 and 80 is not separately used.

[57] These second 3D pattern layers 60, 70 and 80 may have a refractive index higher than that of the first 3D pattern layer 20 of, for example, at least 1.53 and, preferably, 1.54-1.6. If the refractive index of the second 3D pattern layers 60, 70 and 80 is smaller than 1.53, it should be higher than that of the first 3D pattern layer 20. The second 3D patterns 60, 70 and 80 may have an average thickness of about 5~100/M. Also, although unshown in the drawings, if the second 3D pattern layers 70 and 80 respectively have the upper surfaces with the lenticular pattern, the micro lens pattern or the Fresnel pattern, the functional bead 15 may be added between surfaces of the transparent base 10 and the first 3D pattern layer 20.

[58] The optical sheets according to another embodiment of the present invention described as above are provided with the plurality of 3D pattern layers, include silicon acrylate in the upper 3D pattern layer, and selectively have the functional beads or the surface roughness. Thus, the diffusion function, the condensing function and a protection function can be secured by the single optical sheet.

[59] Now, a liquid crystal display according to an embodiment of the present invention will be described with reference to FIG. 9.

[60] A liquid crystal display 200 according to this embodiment of the present invention includes a backlight assembly 210, a display panel 220, upper and lower containers 230 and 240, an intermediary mold frame 250, a lower mold frame 260, and front and rear covers 280 and 290.

[61] First, the backlight assembly 210 will be described.

[62] As illustrated in FIG. 9, the backlight assembly 210 includes a lamp unit 211 for supplying light, a light guide member 212 for upward guiding the light from the lamp unit 211, and an optical sheet 100 for diffusing and condensing the light from the light guide member 212.

[63] The lamp unit 211 may include a lamp 211a and a lamp reflector plate 21 Ib. The lamp 211a may be a slim and long cylindrical Cold Cathode Fluorescent Lamp (CCFL), for example. Although unshown in the drawing, the lamp 21 Ia may be a flat type fluorescent knp, for example. In this case, the light guide member 212 can be deleted. The lamp reflection pkte 21 Ib reflects the light from the lamp 211a toward the light guide member 212 side.

[64] The lamp unit 211 may be disposed on both sides of the light guide member 212, or, the lamp unit 211 may be disposed on one side thereof although not illustrated in the drawing. When the lamp unit 211 is disposed on both sides of the light guide member 212, a shape of the light guide member 212 may be a flat type. Otherwise, if the knp unit 211 is disposed on one side of the light guide member 212, the light guide member 212 may have a wedge type.

[65] The light guide member 212 is formed of a pkstic based material such as acryl, and may have various patterns printed in a lower surface thereof in order to shift the advancing direction of the light incident to the inside of the light guide member 212 toward the dispky panel 220 side.

[66] A reflection pkte 213 is disposed on a rear surface of the light guide member 212 to reflect the light outgoing to a rear surface of the light guide member 212 toward an upper surface side thereof. The reflection pkte 213 decreases a loss of the light incident to the dispky panel 220, and simultaneously enhances the consistency of the light transmitted to the upper surface of the light guide member 212.

[67] The optical sheet 100 disposed on the upper surface of the light guide member 212 includes a first 3D pattern layer 20 and a second 3D pattern layer 30 sequentially disposed on a transparent base 10. The optical sheet 100 may further has functional beads 15 between the transparent base 10 and the first 3D pattern layer 20. Also, the optical sheet 100 may have a predetermined surface roughness in the top of a second 3D pattern layer 40.

[68] The optical sheet 100 refracts and condenses the light outgoing through the light guide member 212 in a direction perpendicukr to the dispky panel 220, and diffuses the resultant light to enhance the luminance consistency of the light, widen the viewing angle, and hide the pattern of the light guide member 212. Furthermore, the optical sheet 100 includes silicon acrykte in the second 3D pattern kyer 30, so that the surface of the optical sheet 10 and surfaces of adjacent parts are not damaged even if a masking film or a protective film is not separately used.

[69] It is obvious that the backlight assembly 210 may be furnished with the optical sheets

110, 120, 130, 140, 150, 160 and 170 according to one and the other embodiments of the present invention in addition to the above-described optical sheet 100.

[70] The dispky panel 220 for displaying images is disposed on an upper surface of the backlight assembly 210 formed as above. The display panel 220 includes a first display plate 221 having a color filter that makes the light supplied from the backlight assembly 210 reveal as a predetermined color by pixels of red, green and blue surrounded by a black matrix, a second display plate 222 having thin film transistors arranged as a matrix, and a liquid crystal layer (not shown) formed between the first display plate 221 and the second display plate 222.

[71] Further to the first display plate 221 and the second display plate 222, the display panel 220 includes data and gate printed circuit boards 225 and 226. The data and gate printed circuit boards 225 and 226 are connected to the display panel 220 using data and gate tape carrier packages 223 and 224 which are a kind of a flexible circuit board. Also, the data and gate printed circuit boards 225 and 226 supply a driving signal and a timing signal to a gate line and a data line of the thin film transistor to control an array angle of a liquid crystal and a period of arranging the liquid crystal constituting the liquid crystal layer.

[72] Although not illustrated, a polarizing plate is provided to a side of the display panel

220, which is opposite to the backlight assembly 210.

[73] The upper container 230 fixes the display panel 220 by being fitted with the intermediary mold frame 250 installed to the upper side of the lower container 240 using a coupling unit such as screws, and has a plurality of coupling windows (not shown).

[74] The lower container 240 accommodates the backlight assembly 210, and is shaped to securely place the backlight assembly 210 thereon as a rectangle, for example. A screw groove (not shown) is formed in a rear surface of the lower container 240.

[75] The lower mold frame 260 receives the lower container 240, and a plurality of coupling projections (not shown) for being hook-fitted with the coupling windows (not shown) formed in the upper container 230 are formed on a sidewall of the lower mold frame 260. The printed circuit board cover 270 is grounded to the lower container 240 using the coupling unit such as the screws to block a short and an electric wave produced in the data printed circuit board 225.

[76] While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. Industrial Applicability

[77] According to the present invention, an optical sheet, and a backlight assembly and a liquid crystal display having the same as described above, a single optical sheet has the multi-function of the photo refractivity, optical condensing and light diffusion, and requires neither a masking film nor a protective film, thereby being excellent in cost reduction, productivity, and workability while the lighter, thinner, simpler and smaller liquid crystal display can be realized.

Claims

[I] An optical sheet comprising: a transparent base; and a plurality of three-dimensional pattern layers sequentially disposed on one surface of the transparent base. [2] The optical sheet of claim 1, further comprising: functional beads interposed between the transparent base; and a three-dimensional pattern kyer disposed on the lowest place of the plurality of three-dimensional pattern layers. [3] The optical sheet of claim 1, comprising a predetermined surface roughness at the top of a three-dimensional pattern layer disposed on the uppermost place of the plurality of three-dimensional pattern layers. [4] The optical sheet of claim 1, wherein the uppermost three-dimensional pattern kyer out of the plurality of three-dimensional pattern layers comprises silicon acrykte. [5] The optical sheet of claim 1, wherein the plurality of three-dimensional pattern kyers have a refractive index increased when reaching from the lower portion toward the upper portion. [6] An optical sheet comprising: a transparent base; a first three-dimensional pattern kyer disposed on one side of the transparent base; and a second three-dimensional pattern kyer disposed on the first three-dimensional pattern kyer. [7] The optical sheet of claim 6, wherein the first three-dimensional pattern kyer is shaped as embossing. [8] The optical sheet of claim 6, wherein the second three-dimensional pattern kyer comprises at least one pattern selected from a prism pattern, a lenticukr pattern, a micro lens pattern, and a Fresnel pattern. [9] The optical sheet of claim 6, wherein the second three-dimensional pattern kyer comprises a predetermined surface roughness at the top thereof. [10] The optical sheet of claim 9, wherein the surface roughness ranges from 0.05 to

0.5/M.

[I I] The optical sheet of claim 9, wherein a rate of an area with the surface roughness at the top of the second three-dimensional pattern layer is 0.01-10% with respect to overall area of the three-dimensional pattern of the second three-dimensional pattern layer. [12] The optical sheet of claim 6, wherein the first three-dimensional pattern layer has a low refractive index, and the second three-dimensional pattern layer has a high refractive index. [13] The optical sheet of claim 6, wherein the second three-dimensional pattern layer comprises silicon acrylate. [14] The optical sheet of claim 6, further comprising functional beads between the transparent base and the first three-dimensional pattern layer. [15] The optical sheet of claim 14, wherein the functional beads are light diffusion beads.

[16] The optical sheet of claim 6, wherein the upper surface of the first three- dimensional pattern layer and the lower surface of the second three-dimensional pattern layer have substantially complementary shape. [17] A backlight assembly comprising: a lamp unit; a light guide member for upward guiding light from the lamp unit; and an optical sheet of any one of claims 1 through 16, disposed on an upper surface of the light guide member. [18] A liquid crystal display comprising: a display panel; and a backlight assembly of claim 16 for supplying the light to the display panel.