WO2008115008A1 - Optical sheets - Google Patents
Optical sheets Download PDFInfo
- Publication number
- WO2008115008A1 WO2008115008A1 PCT/KR2008/001554 KR2008001554W WO2008115008A1 WO 2008115008 A1 WO2008115008 A1 WO 2008115008A1 KR 2008001554 W KR2008001554 W KR 2008001554W WO 2008115008 A1 WO2008115008 A1 WO 2008115008A1
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- WO
- WIPO (PCT)
- Prior art keywords
- light
- structures
- optical sheet
- layer
- light diffusion
- Prior art date
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Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/12—Reflex reflectors
- G02B5/122—Reflex reflectors cube corner, trihedral or triple reflector type
- G02B5/124—Reflex reflectors cube corner, trihedral or triple reflector type plural reflecting elements forming part of a unitary plate or sheet
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
- G02B6/0051—Diffusing sheet or layer
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/02—Diffusing elements; Afocal elements
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
- G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/1336—Illuminating devices
- G02F1/133602—Direct backlight
- G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
Definitions
- the present invention relates to an optical sheet for use in liquid crystal displays.
- CRT Cathode Ray Tube
- LCDs liquid crystal displays
- PDPs plasma display panels
- FEDs field emission displays
- organic electroluminescent displays organic electroluminescent displays
- LCDs a technologically intensive product resulting from a combination of liquid crystal-semiconductor techniques, are advantageous because they are thin and light and consume little power. Therefore, research and development into structures and manufacturing techniques thereof is continuing.
- LCDs which have already been applied in fields such as notebook computers, monitors for desktop computers, and portable personal communication devices (PDAs and mobile phones) , are being manufactured in larger sizes, and thus, it is possible to apply LCDs to large- sized TVs, such as HD (High-Definition) TVs.
- HD High-Definition
- the LCD serving as a device for adjusting light transmittance using the electrical properties of liquid crystal material, emits light from a light source lamp mounted to the back surface thereof, and the light thus emitted is passed through various functional prism films or sheets to thus cause light to be uniform and directional, after which such controlled light is also passed through a color filter, thereby realizing red, green, and blue (R, G, B) colors.
- the LCD is of an indirect light emission type, which realizes an image by controlling the contrast of each pixel through an electrical method.
- a light- emitting device provided with a light source is regarded as important in determining the quality of the image of the LCD, including brightness and uniformity.
- a light-emitting device is mainly exemplified by a backlight unit.
- a general backlight unit is illustrated in FIG. 1.
- a backlight unit causes light to be emitted using a light source 1 such as a cold cathode fluorescent lamp (CCFL) , so that such emitted light is sequentially passed through a light guide plate 3, a diffusion sheet 4, and a prism sheet 5, thus reaching a liquid crystal panel 6.
- CCFL cold cathode fluorescent lamp
- the light guide plate 3 functions to transfer light emitted from the light source in order to distribute it over the entire front surface of the liquid crystal panel 6, which is planar, and the diffusion sheet 4 realizes uniform light intensity over the entire front surface.
- the prism sheet 5 functions to control the light path so that light traveling in various directions through the diffusion sheet 4 is transformed within a range of viewing angles ⁇ suitable for enabling the image to be viewed by an observer.
- a reflection sheet 2 is provided under the light guide plate 5 to reflect light, which does not reach the liquid crystal panel 6 and is outside of the light path, so that such light is used again, thereby increasing the efficiency of use of the light source.
- a plurality of films having various functions is mounted, thereby causing light interference, including a Newton' s Ring phenomenon, occurring as a result of use of the plurality of films, or a wet-out phenomenon, by which air is removed from the contact surface between the films .
- light interference including a Newton' s Ring phenomenon, occurring as a result of use of the plurality of films, or a wet-out phenomenon, by which air is removed from the contact surface between the films .
- light interference including a Newton' s Ring phenomenon, occurring as a result of use of the plurality of films, or a wet-out phenomenon, by which air is removed from the contact surface between the films .
- the present invention provides an optical sheet, which includes a prism layer that can be easily formed on a light diffusion layer and exhibits various functions in the form of a single sheet, thus ensuring good visibility.
- the present invention provides an optical sheet, which has brightness as high as in the conventional use of a light diffusion sheet, a prism sheet and a protective film, which are in a layered form, and realizes a wide viewing angle.
- the present invention provides an optical sheet, in which a difference in refractive index between a prism layer and a binder resin of a light diffusion layer is controlled, so that the total amount of light that is reflected is decreased, thus increasing efficiency of incident light.
- the present invention provides an optical sheet, in which the number of sheets to be mounted in a backlight unit is decreased.
- the present invention provides an optical sheet, which includes a prism layer that can be easily formed on a light diffusion layer and prevents the loss of light due to the overlapping of particles .
- the present invention provides an optical sheet, which reduces contact with an upper panel, thus preventing the loss of brightness or damage to a prism layer.
- an optical sheet may comprise a transparent substrate layer; a light diffusion layer formed on one surface of the transparent substrate layer and containing a binder resin and light- diffusing particles, in which a difference in refractive index between the light-diffusing particles and the binder resin is 0.05 or less; and a prism layer formed on the light diffusion layer.
- the optical sheet may comprise a damage prevention layer formed on the other surface of the transparent substrate layer and containing a binder resin and particles.
- the light diffusion layer may have a cross-sectional structure in which the light-diffusing particles are dispersed in a mono layer.
- the light diffusion layer may comprise 10 ⁇ 500 parts by weight of light-diffusing particles having a particle size of 1-50 ⁇ m based on 100 parts by weight of a solid content of the binder resin.
- the light diffusion layer may comprise 10 ⁇ 300 parts by weight of light-diffusing particles having a particle size of l ⁇ 50 ⁇ m based on 100 parts by weight of a solid content of the binder resin.
- the prism layer may have a refractive index which is 0.01-0.2 higher than the refractive index of the binder resin of the light diffusion layer.
- the prism layer may be imparted with a structured surface by arranging a plurality of three-dimensional (3D) structures selected from among 3D column structures having a semicircular or semi-elliptical cross-section, 3D column structures having a triangular or a polygonal cross- section, circular cone structures, and polypyramid structures.
- 3D three-dimensional
- the prism layer may be imparted with a structured surface by arranging a plurality of 3D structures selected from among 3D column structures having a semicircular or semi-elliptical cross-section, 3D column structures having a triangular or a polygonal cross-section, circular cone structures, and polypyramid structures, and the 3D structures may comprise at least two types of 3D structures having the same width and different heights, which are arranged regularly or irregularly.
- the prism layer may be imparted with a structured surface by arranging a plurality of 3D structures selected from among 3D column structures having a semicircular or semi-elliptical cross-section, 3D column structures having a triangular or a polygonal cross-section, circular cone structures, and polypyramid structures, and the 3D structures may comprise at least two types of 3D structures having different widths and the same height, which are arranged regularly or irregularly.
- the prism layer may be imparted with a structured surface by arranging a plurality of 3D structures selected from among circular cone structures and polypyramid structures, and the 3D structures having the same shape and dimension may be continuously arranged to be adjacent to each other, in which imaginary lines that link peaks of the 3D structures may be in a nonlinear form when viewed from above .
- the damage prevention layer may comprise particles which are the same as or different from the particles of the light diffusion layer.
- a backlight unit assembly may comprise an optical sheet, including a transparent substrate layer, a light diffusion layer formed on one surface of the transparent substrate layer and containing a binder resin and light-diffusing particles, in which a difference in refractive index between the light-diffusing particles and the binder resin is 0.05 or less, and a prism layer formed on the light diffusion layer; and a light diffusion sheet disposed on an upper surface or a lower surface of the optical sheet.
- a backlight unit assembly may comprise an optical sheet, including a transparent substrate layer, a light diffusion layer formed on one surface of the transparent substrate layer and containing a binder resin and light-diffusing particles, in which a difference in refractive index between the light-diffusing particles and the binder resin is 0.05 or less, and a prism layer formed on the light diffusion layer; and a prism sheet disposed on an upper surface or a lower surface of the optical sheet.
- a back unit assembly may comprise an optical sheet, including a transparent substrate layer, a light diffusion layer formed on one surface of the transparent substrate layer and containing a binder resin and light-diffusing particles, in which a difference in refractive index between the light-diffusing particles and the binder resin is 0.05 or less, and a prism layer formed on the light diffusion layer; and a protective film disposed on an upper surface of the optical sheet.
- an optical sheet functions to uniformly diffuse light emitted from a light guide plate or a diffusion sheet and to increase brightness at the same time, includes a prism layer which can be easily formed on a light diffusion layer, and can reduce the loss of light.
- part of a conventional optical film for example, a protective film, may be omitted, and thus, the optical sheet of the present invention can prevent light interference, the loss of light, such as scattering or absorption, and damage to a film.
- the shape of the surface of the prism layer can be controlled, contact thereof with a panel can be reduced, thereby preventing brightness from being decreased due to damage to the prism layer.
- FIG. 1 is a schematic view illustrating a typical backlight unit
- FIG. 2 is a cross-sectional view illustrating an optical sheet according to a first embodiment of the present invention
- FIG. 3 is a cross-sectional view illustrating an optical sheet according to a second embodiment of the present invention.
- FIG. 4 is a cross-sectional view and a perspective view illustrating an optical sheet according to a third embodiment of the present invention.
- FIG. 5 is a cross-sectional view and a perspective view illustrating an optical sheet according to a fourth embodiment of the present invention.
- an optical sheet has a structure composed of a transparent substrate layer, a light diffusion layer formed on one surface of the transparent substrate layer, and a prism layer formed on the light diffusion layer.
- the transparent substrate layer examples include a polyethyleneterephthalate film, a polycarbonate film, a polypropylene film, a polyethylene film, a polystyrene film, or a polyepoxy film. Particularly useful is a polyethyleneterephthalate film or a polycarbonate film.
- the thickness of the transparent substrate layer may be set in the range of 10-1000 ⁇ m. In particular, when the transparent substrate layer is 15-400 ⁇ m thick, mechanical strength, thermal stability, and flexibility are advantageous, and the loss of transmitted light may be prevented.
- the light diffusion layer which is formed on one surface of the transparent substrate layer, is formed by dispersing light-diffusing particles in a binder resin.
- the difference in refractive index between the binder resin and the light-diffusing particles is controlled to 0.05 or less, so that the internal reflections of light occurring from the difference in refractive index between two materials are reduced, thereby increasing the efficiency with which light enters the prism layer.
- the binder resin includes a resin that adheres well to the transparent substrate layer and has good compatibility with light-diffusing particles dispersed therein, for example, a resin in which light-diffusing particles are uniformly dispersed so that they are not separated or precipitated.
- the resin include acrylic resin, including homopolymers, copolymers, or terpolymers of unsaturated polyester, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, n- butyl methacrylate, n-butylmethyl methacrylate, acrylic acid, methacrylic acid, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, acrylamide, methylolacrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, and 2- ethylhexyl acrylate, urethane resin, epoxy resin, and melamine resin.
- acrylic resin including homopolymers, copolymers, or terpolymers of unsaturated polyester, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate,
- the light-diffusing particles may be used in an amount of 10 ⁇ 500 parts by weight, and preferably 10-300 parts by weight, based on 100 parts by weight of the binder resin, and have a particle size of l ⁇ 50 ⁇ m
- the light-diffusing particles may be dispersed in the form of a mono layer in the light diffusion layer, and are suitable for realizing desired light diffusion effects, and furthermore, white turbidity and separation of the particles, which may be caused by excessive use thereof, may be prevented.
- the light-diffusing particles contained in the light diffusion layer may be dispersed in the form of a mono layer or a multilayer.
- the light-diffusing particles include organic particles or inorganic particles.
- the organic particles include acrylic particles, including homopolymers or copolymers of methyl methacrylate, acrylic acid, methacrylic acid, hydroxyethyl methacrylate, hydroxypropyl methacrylate, acrylamide, methylolacrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate, olefin particles, including polyethylene, polystyrene, and polypropylene, acryl-olefin copolymer particles, and multilayer multicomponent particles prepared by forming a layer of homopolymer particles and then forming a layer of another type of monomer there
- the above organic and inorganic particles are merely illustrative, are not limited to the examples listed above, and may be replaced with other known materials as long as the main purpose of the present invention is achieved, as will be apparent to those skilled in that art.
- the case in which the type of material is changed also falls within the technical scope of the present invention.
- Typical examples of the material for the prism layer include polymer resin, including UV curable resin or heat curable resin. Particularly useful is a resin composition that is very transparent and is capable of forming a crosslink bond adequate for maintaining the shape of an optical structure. Examples thereof include epoxy, polyethylol, unsaturated polyester, unsaturated fatty acid ester, aromatic vinyl compounds, unsaturated fatty acids and derivatives thereof, unsaturated dibasic acids and derivatives thereof, and vinyl cyanide compounds such as methacrylonitrile. Specifically, styrene resin and
- (meth) acrylic acid ester resin are exemplary. Among them, the use of (meth) acrylic acid ester resin, which is very transparent, is preferable.
- Such resin includes oligomers, such as polyurethane (meth) acrylate, epoxy (meth) acrylate, and polyester (meth) acrylate, and may be used alone or diluted with a (meth) acrylate monomer having a polyfunctional or monofunctional group.
- the prism layer may be given a structured surface by arranging a plurality of 3D structures selected from among 3D column structures having a semicircular or semi-elliptical cross-section, 3D column structures having a triangular or polygonal cross-section, circular cone structures, and polypyramid structures, but the present invention is not limited to such shapes.
- the optical sheet of the present invention may exhibit both a diffusion function and a light-collecting function, and thus the additional use of a protective film may be omitted. In this case, however, there is a concern about damage to the structured surface of the prism layer because the prism layer is brought into contact with a panel.
- the surface of the prism layer is structured by arranging the plurality of 3D structures, selected from among 3D column structures having a semicircular or semi-elliptical cross-section, 3D column structures having a triangular or polygonal cross-section, circular cone structures, and polypyramid structures, in which the 3D structures include at least two types of 3D structures having the same width and different heights, which are arranged regularly or irregularly.
- FIG. 2 shows an optical sheet including a prism layer 30 according to a first embodiment, having a structured surface by arranging a plurality of 3D column structures, the cross- section of which is triangular.
- the prism layer 30 is composed of two types of 3D structures 30a, 30b having the same width a and different heights b, which are regularly arranged.
- the cross-section of which is triangular are regularly arranged is illustrated.
- the cross-section thereof may have a semicircular shape, a semi-elliptical shape, or a polygonal shape, and furthermore, other types having the same width and different heights may coexist, and can be regularly or irregularly arranged.
- the surface structure of a prism layer according to a second embodiment for achieving the same purpose of the present invention includes an arrangement of a plurality of 3D structures selected from among 3D column structures having a semicircular or semi-elliptical cross- section, 3D column structures having a triangular or polygonal cross-section, circular cone structures, and polypyramid structures, in which the 3D structures may include at least two types of 3D structures having the same height and different widths, arranged regularly or irregularly. An example thereof is illustrated in FIG. 3.
- FIG. 3 shows an optical sheet including a prism layer 40 having a structured surface by arranging a plurality of 3D column structures, the cross-section of which is triangular.
- a prism layer 40 having a structured surface by arranging a plurality of 3D column structures, the cross-section of which is triangular.
- two types of 3D structures 40a, 40b, having the same width a and different heights b, are regularly arranged.
- the cross-section of which is triangular are regularly arranged is illustrated.
- the cross-section thereof may have a semicircular shape, a semi-elliptical shape, or a polygonal shape, and also, other types having the same height and different widths may coexist, and may be regularly or irregularly arranged.
- the surface of a prism layer according to a third embodiment may be structured by arranging a plurality of 3D structures selected from among 3D column structures having a semicircular or semi-elliptical cross- section and 3D column structures having a triangular or polygonal cross-section, in which the arrangement of the 3D structures may be nonlinear when viewed from above.
- FIG. 4 shows a prism layer 50, in which 3D structures having a triangular cross-section are arranged in a zigzag form when viewed from above.
- the cross-section thereof may have a semicircular shape, a semi-elliptical shape, or a polygonal shape, and further, the arrangement thereof may have an S form, which is also nonlinear, as an alternative to the zigzag form.
- the surface of a prism layer according to a fourth embodiment may be structured by arranging a plurality of 3D structures selected from among circular cone structures and polypyramid structures .
- Such 3D structures having the same shape and dimension are continuously arranged to be adjacent to each other, in which imaginary lines that link the peaks of the respective 3D structures may be in a nonlinear form when viewed from above .
- FIG. 5 shows the case where 3D structures 60a having a triangular pyramid shape are arranged to be adjacent to each other, in which imaginary lines that link the peaks of the respective triangular pyramids are in a zigzag form.
- the 3D structures may have a circular cone shape or a polypyramid shape, and may be arranged in an S form, which is also nonlinear, as an alternative to the zigzag form.
- the prism layer when the prism layer is formed to have a refractive index which is only 0.01-0.2 higher than that of the binder resin of the light diffusion layer, the total amount of light that is reflected may be decreased, advantageously reducing the loss of light.
- a damage prevention layer may be further formed on the other surface of the transparent substrate layer, that is, on the surface of the transparent substrate layer opposite the surface having the light diffusion layer.
- the damage prevention layer is formed by dispersing particles in a binder resin.
- a resin that adheres well to the transparent substrate layer and has good compatibility with particles dispersed therein that is, a resin in which particles are uniformly dispersed so that they are not separated or precipitated, and specific examples thereof may be the same as the binder resin of the light diffusion layer.
- the particles contained in the damage prevention layer include organic particles or inorganic particles, and examples thereof may be the same as or different from the light-diffusing particles contained in the light diffusion layer.
- front-surface brightness may be decreased due to the diffusion of light, and also, in the case of inorganic particles, light may be reflected from the surface of particles or absorbed thereon to thus decrease front- surface brightness, undesirably resulting in reduced efficiency of use of light. Accordingly, excessive use of the particles is undesirable.
- the surface protrusions of the damage prevention layer function to reduce the contact area with the facing surface in the process device, or with another optical film, which is disposed thereon, during the loading or storage of optical films or the assembly of the optical films with other parts, thereby preventing surface damage, which may be caused by separation into respective films, transport or assembly.
- the optical sheet thus manufactured light is primarily diffused while passing through the particles of the damage prevention layer, and is then uniformly diffused by the light-diffusing particles of the light diffusion layer through the transparent substrate layer, followed by passing such diffused light through the prism layer.
- the difference in refractive index between the light-diffusing particles and the binder resin in the light diffusion layer is decreased, thus reducing the internal reflection of light, thereby further increasing the efficiency of use of light.
- films, which are conventionally separately manufactured and layered to impart a light diffusion function and a function of increasing brightness may be manufactured in an integrated form, thus decreasing the manufacturing process and cost.
- the optical sheet of the present invention is favorable because the number of films to be provided in an optical sheet assembly for a backlight unit may be decreased.
- a backlight unit assembly comprising the optical sheet as above and a light diffusion film or a prism film formed on any one surface thereof may be provided, thereby further increasing brightness compared to when using only the optical composite sheet. Further, even when a prism layer is provided as the uppermost layer without the use of a protective film, good visibility may be realized.
- a backlight unit assembly comprising the optical sheet as above and a protective film formed on any one surface thereof may be provided, thereby realizing brightness equal to when layering the light diffusion film, the prism film and the protective film and further increasing visibility. Therefore, in the case where the optical sheet according to the preferred embodiments of the present invention is applied to the backlight unit, the optical sheet is advantageous because the degree of improvement of brightness relative to the number of sheets to be mounted is high and the difference in refractive index between the light-diffusing particles and the binder resin in the light diffusion layer is controlled to 0.05 or less, thus realizing a backlight unit assembly having a wide viewing angle.
- a refractive index was measured using an ABBE refractometer (available from ATAGO) .
- ABBE refractometer available from ATAGO
- model number IT is suitable for measurement of a sample in a refractive index range from 1.300 to 1.700
- model number 4T is suitable for measurement of a sample in a refractive index range from 1.470 to 1.870.
- the measurement was typically conducted at room temperature (25 ° C) .
- Example 1 100 parts by weight of acrylic resin (52-666, Aekyung Chemical) was diluted with 70 parts by weight of methylethylketone and 50 parts by weight of toluene, thus preparing a binder resin having a refractive index of 1.50, after which spherical polymethylmethacrylate particles
- MH20F, Kolon having an average particle size of 20 ⁇ m and a refractive index of 1.50 were mixed in an amount of 110 parts by weight based on the binder resin, monodispersed in the form of a mono layer using a milling machine, applied on one surface of a super-transparent polyethyleneterephthalate film (FHSS, Kolon) 188 ⁇ m thick as a transparent substrate layer using a gravure coater, and then cured at 120 ° C for 60 sec, thus forming a light diffusion layer (refractive index: 1.50) having a dry thickness of 25 ⁇ m.
- FHSS super-transparent polyethyleneterephthalate film
- a photosensitive composition comprising 75 parts by weight of urethane acrylate, 20 parts by weight of 2- phenylethyl methacrylate, 3 parts by weight of 1,6- hexanediol acrylate, and 2 parts by weight of a BAPO-based photoinitiator was applied, and the frame of a prism-shaped roller was coated with the photosensitive composition applied on the light diffusion layer, after which UV light
- An optical composite film was manufactured in the same manner as in Example 1, with the exception that a prism layer having nonlinear triangular prisms and a refractive index of 1.53 was formed on one surface of the light diffusion layer. ⁇ Example 3>
- Example 4 An optical composite film was manufactured in the same manner as in Example 1, with the exception that the light-diffusing particles were dispersed in a multilayer form in the course of formation of the light diffusion layer. As such, the light diffusion layer was 30-35 ⁇ m thick and had a refractive index of 1.50. ⁇ Example 4>
- An optical composite film was manufactured in the same manner as in Example 2, with the exception that the light-diffusing particles were dispersed in a multilayer form in the course of formation of the light diffusion layer.
- the light diffusion layer was 30 ⁇ 35 (M thick and had a refractive index of 1.50.
- Example 5 An optical sheet was manufactured in the same manner as in Example 2, with the exception that, in the course of formation of the light diffusion layer, particles having a refractive index of 1.52 were used instead of the spherical polymethylmethacrylate particles having an average particle size of 20 (M and a refractive index of 1.50.
- An optical sheet was manufactured in the same manner as in Example 2, with the exception that, in the course of formation of the light diffusion layer, particles having a refractive index of 1.55 were used instead of the spherical polymethylmethacrylate particles having an average particle size of 20 (M and a refractive index of 1.50.
- An optical sheet was manufactured in the same manner as in Example 1, with the exception that a prism layer having a refractive index of 1.6 was formed.
- An optical sheet was manufactured in the same manner as in Example 2, with the exception that, in the course of formation of the light diffusion layer, particles having an average particle size of 5 (M were used. ⁇ Example 9>
- a light diffusion film (LD602, Kolon) was disposed on the outer surface of the transparent substrate layer of the optical sheet of Example 2. ⁇ Example 10>
- a protective film (LD143, Kolon) was disposed on the outer surface of the prism layer of the optical composite film of Example 2.
- a prism film (LC213, Kolon) was prepared.
- the prism film of Comparative Example 2 was disposed on the light diffusion film of Comparative Example 1.
- An optical sheet was manufactured in the same manner as in Example 2, with the exception that, in the course of formation of the light diffusion layer, particles having a refractive index of 1.6 were used instead of the spherical polymethylmethacrylate particles having a particle size of
- a light diffusion film (LD602, Kolon) was disposed on the outer surface of the transparent substrate layer of the optical sheet of Comparative Example 5.
- the properties of the optical films of the above examples and comparative examples were evaluated as follows. The evaluation results are shown in Table 1 below.
- One or two of the optical films of the above examples and comparative examples were mounted to a backlight unit for 17" LCD panels, and the brightness values of optionally 13 points were measured using a luminance meter (model number: BM-7, Topcon, Japan), averaged, and then evaluated according to the following: ⁇ : brightness of 4500 cd/m 2 or more
- ⁇ brightness between 3000 cd/m 2 and less than 3500 cd/m 2
- X brightness less than 3000 cd/m 2
- the refractive index of the prism layer was about 0.01 ⁇ 0.2 higher than that of the binder resin of the light diffusion layer, much better results were exhibited.
- the viewing angle was wider than in the case of Comparative Example 3, in which the light diffusion film and the prism film were disposed thereon.
- Comparative Example 5 in which the difference in refractive index between the light-diffusing particles and the binder resin was greater than 0.05 despite the composite film, the brightness and viewing angle were lower than in the examples .
- the optical composite sheets according to the examples could be confirmed to increase the efficiency of use of a light source while minimizing the loss of light.
- the number of sheets was decreased but the brightness was equal thereto, and also, the viewing angle and visibility were superior.
- the particles thus dispersed were applied on one surface of a super-transparent polyethylene terephthalate film (FHSS, Kolon) 125 ⁇ m thick as a transparent substrate layer using a gravure coater, and were then cured at 120 ° C for 60 sec, thus forming a light diffusion layer having a dry thickness of 23 ⁇ .
- FHSS super-transparent polyethylene terephthalate film
- the particles of the light diffusion layer were dispersed in the form of a mono layer.
- one surface of the cured light diffusion layer was coated with a photosensitive composition comprising 80 parts by weight of high-refractive acrylate, 15 parts by weight of 2-phenylethyl methacrylate, 3 parts by weight of 1, ⁇ -hexanediol acrylate, and 2 parts by weight of a BAPO-based photoinitiator, after which UV light (Fusion, 300 watts/inch 2 ) was radiated onto the transparent substrate layer, thus forming a prism layer having linear triangular prisms (with a column shape having a right isosceles triangle cross-section having a width of 50 jM and a height of 25 ⁇ m) .
- the refractive index of the prism layer was 1.53.
- Example 12 An optical sheet was manufactured in the same manner as in Example 11, with the exception that, in the course of formation of the light diffusion layer, particles having a refractive index of 1.52 were used instead of the spherical polymethylmethacrylate particles having a particle size of 20 ⁇ m and a refractive index of 1.50.
- An optical sheet was manufactured in the same manner as in Example 11, with the exception that, in the course of formation of the light diffusion layer, particles having a refractive index of 1.54 were used instead of the spherical polymethylmethacrylate particles having a particle size of 20 /M and a refractive index of 1.50.
- An optical sheet was manufactured in the same manner as in Example 11, with the exception that a prism layer having a refractive index of 1.6 was formed.
- An optical sheet was manufactured in the same manner as in Example 11, with the exception that, in the course of formation of the light diffusion layer, particles having a particle size of 5 (M were used instead of the spherical polymethylmethacrylate particles having a particle size of 20 (M and a refractive index of 1.50.
- An optical sheet was manufactured in the same manner as in Example 11, with the exception that the prism layer was formed such that first pitches (30a of FIG. 2), having a width of 50 [M and a height of 25 /an, and second pitches
- An optical sheet was manufactured in the same manner as in Example 11, with the exception that the prism layer was formed such that first pitches (30a of FIG. 2) , having a width of 50 [M and a height of 25 ⁇ m, and second pitches, (30b of FIG. 2) having a width of 45 ⁇ m and a height of 25 (M, were alternately arranged, as shown in FIG. 3.
- first pitches (30a of FIG. 2) having a width of 50 [M and a height of 25 ⁇ m
- second pitches, (30b of FIG. 2) having a width of 45 ⁇ m and a height of 25 (M, were alternately arranged, as shown in FIG. 3.
- An optical sheet was manufactured in the same manner as in Example 1, with the exception that the prism layer was formed such that pitches having a width of 50 /an and a height of 25 /an were arranged in a zigzag form when viewed from above, as shown in FIG. 4.
- Kolon having an average particle size of 18.1 /an, were mixed in an amount of 130 parts by weight based on the acrylic resin, dispersed using a milling machine, and then applied on one surface of a super-transparent polyethylene terephthalate film (FHSS, Kolon) 125 /an thick using a gravure coater, thus forming a light diffusion layer having a dry thickness of 20 /an, thereby manufacturing an optical film.
- FHSS, Kolon super-transparent polyethylene terephthalate film
- a photosensitive composition comprising 80 parts by weight of high-refractive acrylate, 15 parts by weight of 2-phenylethyl methacrylate, 3 parts by weight of 1, 6-hexanediol acrylate, and 2 parts by weight of a BAPO-based photoinitiator was applied, after which UV light (Fusion, 300 watts/inch 2 ) was radiated onto the transparent substrate layer, thus forming linear triangular prisms, thereby manufacturing an optical film.
- FHSS super- transparent polyethyleneterephthalate film
- the optical film having the linear triangular prisms was disposed on the optical film having the light diffusion layer thereon.
- One or two of the optical films of the above examples and comparative examples were mounted to a backlight unit for 24" LCD panels, and the brightness values of optionally
- Each of the optical films of the above examples and comparative examples was mounted to a backlight unit for 24" LCD panels, and brightness was measured at intervals of 10° in the range of 80° toward each of both sides from the center line perpendicular to the unit, using a luminance meter (model number: BM-7, Topcon, Japan) , and the angle at which brightness was half the maximum brightness was determined.
- BM-7 luminance meter
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Abstract
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Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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CN200880008951.6A CN101636670B (en) | 2007-03-20 | 2008-03-19 | Optical sheets |
US12/532,081 US8506149B2 (en) | 2007-03-20 | 2008-03-19 | Optical sheets |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
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KR20070027093 | 2007-03-20 | ||
KR10-2007-0027093 | 2007-03-20 | ||
KR10-2007-0086733 | 2007-08-28 | ||
KR1020070086733A KR100980068B1 (en) | 2007-08-28 | 2007-08-28 | Multi-functional optic film |
KR10-2007-0095608 | 2007-09-20 | ||
KR1020070095608A KR100980072B1 (en) | 2007-03-20 | 2007-09-20 | Multi-functional optic film |
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WO2008115008A1 true WO2008115008A1 (en) | 2008-09-25 |
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PCT/KR2008/001554 WO2008115008A1 (en) | 2007-03-20 | 2008-03-19 | Optical sheets |
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6343865B1 (en) * | 1998-02-17 | 2002-02-05 | Dai Nippon Printing Co., Ltd. | Non-glare film, polarizing device and display device |
US20020150722A1 (en) * | 1999-05-28 | 2002-10-17 | Hiroko Suzuki | Anti-glare film and process for producing same thereof |
US20040075897A1 (en) * | 1998-08-05 | 2004-04-22 | Mitsubishi Rayon Co., Ltd. | Lens sheet and method of manufacturing the same |
KR20070015077A (en) * | 2005-07-28 | 2007-02-01 | 노프 코포레이션 | Display surface material and a display incorporating the same |
-
2008
- 2008-03-19 WO PCT/KR2008/001554 patent/WO2008115008A1/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6343865B1 (en) * | 1998-02-17 | 2002-02-05 | Dai Nippon Printing Co., Ltd. | Non-glare film, polarizing device and display device |
US20040075897A1 (en) * | 1998-08-05 | 2004-04-22 | Mitsubishi Rayon Co., Ltd. | Lens sheet and method of manufacturing the same |
US20020150722A1 (en) * | 1999-05-28 | 2002-10-17 | Hiroko Suzuki | Anti-glare film and process for producing same thereof |
KR20070015077A (en) * | 2005-07-28 | 2007-02-01 | 노프 코포레이션 | Display surface material and a display incorporating the same |
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