WO2008100057A1 - Feuille de protection de prisme et ensemble unité de rétro-éclairage - Google Patents

Feuille de protection de prisme et ensemble unité de rétro-éclairage Download PDF

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Publication number
WO2008100057A1
WO2008100057A1 PCT/KR2008/000819 KR2008000819W WO2008100057A1 WO 2008100057 A1 WO2008100057 A1 WO 2008100057A1 KR 2008000819 W KR2008000819 W KR 2008000819W WO 2008100057 A1 WO2008100057 A1 WO 2008100057A1
Authority
WO
WIPO (PCT)
Prior art keywords
prism
sheet
protection
layer
haze
Prior art date
Application number
PCT/KR2008/000819
Other languages
English (en)
Inventor
Jong Min Park
Chang Kun Kim
Khung Hwa Kim
Tae Kyung Kim
Original Assignee
Kolon Industries, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR1020070014676A external-priority patent/KR100988766B1/ko
Priority claimed from KR1020070014677A external-priority patent/KR100869474B1/ko
Application filed by Kolon Industries, Inc. filed Critical Kolon Industries, Inc.
Priority to CN2008800047689A priority Critical patent/CN101627324B/zh
Publication of WO2008100057A1 publication Critical patent/WO2008100057A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0273—Diffusing elements; Afocal elements characterized by the use
    • G02B5/0278—Diffusing elements; Afocal elements characterized by the use used in transmission
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
    • G02B5/0226—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures having particles on the surface
    • 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
    • G02B1/105—
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/14—Protective coatings, e.g. hard coatings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/04—Prisms
    • G02B5/045—Prism arrays
    • 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
    • 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
    • G02F1/133607—Direct backlight including a specially adapted diffusing, scattering or light controlling members the light controlling member including light directing or refracting elements, e.g. prisms or lenses

Definitions

  • the present invention relates to a prism protection sheet and a backlight unit assembly, and, more particularly, to a prism protection sheet for use in a backlight unit of a flat panel display, such as a liquid crystal display (hereinafter, referred to as an "LCD”) or a light emitting diode (hereinafter, referred to as an "LED”) , and to a backlight unit assembly, including the prism protection sheet.
  • a flat panel display such as a liquid crystal display (hereinafter, referred to as an "LCD”) or a light emitting diode (hereinafter, referred to as an "LED”)
  • LCD liquid crystal display
  • LED light emitting diode
  • the total brightness of the LCD is determined by the performance of the backlight unit, and thus the backlight unit plays a very important role in the LCD.
  • the backlight unit is largely classified into an edge type and a direct type, and the general structures thereof are illustrated in FIGS. 1 to 3.
  • FIGS. 1 and 2 illustrate an edge type
  • FIG. 3 illustrates a direct type.
  • FIG. 1 shows a normal type backlight unit for notebook computers.
  • the edge type includes a lamp 6 positioned at the edge portion of a light guide plate 2
  • the direct type includes a lamp 6 positioned beneath a diffusion plate 2.
  • the edge type backlight unit is used mainly for notebook computers or monitors 19" or smaller, mobile devices, PDAs, navigation tools, and games, etc.
  • the direct type backlight unit is used for monitors and TVs 20" or smaller.
  • the edge type backlight unit has a structure in which a reflection sheet 1 is disposed at the lowest portion thereof and a light guide plate 2, a lamp 2, a diffusion sheet 3, a prism sheet 4, a prism sheet 4', and a protection sheet 5 are sequentially disposed thereon.
  • the direct type backlight unit has a structure in which a reflection sheet 1 is disposed at the lowest portion thereof and a lamp 6, a diffusion plate 3', a diffusion sheet 3, a prism sheet 4, and a protection sheet 5 are sequentially disposed thereon.
  • the reflection sheet 1 functions to maximally reflect light emerging downward such that the light is directed upward, in order to increase the efficiency of the lamp.
  • Such a lamp 6 is exemplified by a cold cathode fluorescent lamp (CCFL) .
  • CCFL cold cathode fluorescent lamp
  • the light guide plate 2 used for the edge type backlight unit functions to uniformly transfer light, generated from the lamp 2 positioned at the edge portion thereof, toward the entire surface of the backlight unit. That is, the light guide plate 2 is used to primarily convert the light of the fluorescent lamp 2, which approximates a linear light source, into a surface light source. Light that is converted into a surface light source by the light guide plate 2 shows non-uniform brightness over the entire surface thereof. That is, although the linear light source of the lamp 6 is converted into the surface light source by the light guide plate 2, the uniformity of light is partially decreased, thus making it impossible to obtain a desired uniform light source for a backlight unit.
  • the diffusion sheet 3 as above is applied on the light guide plate 2.
  • the diffusion sheet 3 functions to diffuse light emerging from the light guide plate 2.
  • brightness which is partially non-uniform
  • the propagation direction of light is diffused toward the front surface thereof, thus increasing front-surface brightness.
  • light emerging from the light guide plate 2 is mainly propagated not in the front surface direction but in a direction deflected from the front surface direction by about 60°.
  • the diffusion sheet 3 is responsible for diffusing light in all directions, thereby increasing brightness in the front surface direction.
  • the use of the diffusion sheet is advantageous as mentioned above, it is disadvantageous in view of the loss of total amount of light emerging from the light guide plate. So, as much light as possible should be guided in the front surface direction, in order to realize desired backlight unit functions.
  • the prism sheet 4 is additionally applied on the diffusion sheet 3.
  • the prism sheet 4 functions to collect light (diffused in all directions) from the diffusion sheet 3 in the front surface direction.
  • the use of the prism sheet 4 on the diffusion sheet 3 results in an increase in front-surface brightness to about 1.5 times or more. Accordingly, in almost all backlight units for LCDs, the prism sheet 4 is adopted. Because the structural properties of the prism sheet 4 are such that it is easily damaged by external contact, a protection sheet is further provided on the prism sheet 4, thus completing the backlight unit.
  • the structure of the direct type backlight unit is the same as that of the edge type backlight unit, in terms of the use of the reflection sheet or reflection plate 1 at the lowest portion thereof.
  • the direct type backlight unit includes a plurality of long thin linear fluorescent lamps ⁇ , which are disposed parallel to each other over the entire surface of the backlight unit.
  • the diffusion plate 3' is additionally disposed thereon.
  • the diffusion plate 3' functions to hide the lines of the lamps 6, disposed linearly, and to uniformly diffuse light.
  • the diffusion sheet 3 is also applied on the diffusion plate 3' so that a diffusion function, which is dissatisfactory because only the diffusion plate is used, is supplemented.
  • the use of the prism sheet 4 and the protection sheet 5 on the diffusion sheet 3 is the same as in the edge type backlight unit .
  • the prism protection sheet 5 Used in either the edge type backlight unit or the direct type backlight unit, the prism protection sheet 5 is required to have various properties, and specifically, should exhibit high brightness, superior ability to block the prism peaks, and excellent processability because it is subjected to various processes, including printing, cutting, and machining, after being disposed on the prism sheet 4, and furthermore, the prism protection sheet itself should not damage the surface of the prism after being disposed on the prism sheet.
  • the prism protection sheet has a structure provided with a substrate film 51, 501 and protection layers 52, 53, 502, 503 on both surfaces of the substrate film, as shown in FIGS. 4 and 5.
  • a substrate film 51, 501 and protection layers 52, 53, 502, 503 on both surfaces of the substrate film, as shown in FIGS. 4 and 5.
  • the surface of the prism protection sheet in contact with the prism layer is referred to as a first protection layer 53, 503, and the other surface of the prism protection sheet is referred to as a second protection layer 52, 502.
  • the protection layer is formed by applying a composition solution containing a binder and light-diffusing particles, and in particular, the second protection layer 53, 503 requires the use of particles in a large amount or in a large size in order to increase brightness through the diffusion of light.
  • Korean Unexamined Patent Publication No. 2003-0094609 discloses a prism protection sheet, as shown in FIG. 4, and a backlight unit assembly, as shown in FIG. 7.
  • the prism protection sheet is constructed in a manner such that, on one surface of the substrate film 501, having a thickness of 100-200 /an, a light diffusion layer (2 nd protection layer, 502), having a thickness of 10 ⁇ 50 /an and surface roughness of 0.05 ⁇ 5 /an, is formed using a composition in which a light-diffusing agent 50 having an average particle size of 3-30 /an is dispersed in a binder resin, and on the other surface thereof, a rear diffusion layer (1 st protection layer, 503) having a thickness of l ⁇ 10 /an and surface roughness of 0.001-1.0 /an is formed using a composition in which a light-diffusing agent 50' having an average particle size of 1-5 ⁇ rn is dispersed in a binder resin.
  • One surface of the substrate film is provided with the light diffusion layer (2 nd protection layer, 502) having surface roughness (Ra) of 0.05-5.0 ⁇ m to diffuse incident light from the light source so as to increase brightness, block the prism peaks, and improve the ease of processing for printing, cutting, and hole machining.
  • the other surface thereof is provided with the rear diffusion layer (1 st protection layer, 503) having Ra of 0.001-1.0 fm, which is in direct contact with the prism peaks, so as to exhibit no blocking by the prism peaks and no damage to the prisms upon vibration.
  • Korean Unexamined Patent Publication No. 2005-0113921 discloses a backlight unit assembly for preventing prisms from breaking, in which the prism protection sheet used therein has a structure in which the first protection layer 53 of the prism protection sheet in contact with the prisms, as shown in FIG. 5, is flattened, thus preventing damage to the prisms.
  • the backlight unit assembly, including such a protection sheet, is illustrated in FIG. 8.
  • the surface of the prism protection sheet in contact with the prisms that is, the first protection layer
  • the amount or size of particles used for the formation of the first protection layer is smaller than that of the second protection layer
  • damage to the prism peaks may be prevented, but the problem in which a view angle is decreased is caused thereby.
  • a plurality of large particles is positioned in the surface layer, undesirably leading to a poor outer appearance .
  • the present invention in the formation of protection layers on both surfaces of a substrate film using a composition containing light- diffusing particles, in the case where the protection layer in contact with prisms has haze higher than that of the surface protection layer, the view angle may be widened. Therefore, the present invention provides a prism protection sheet, which is capable of increasing a view angle and ensuring a uniform outer appearance while satisfying front-surface brightness required therefor.
  • the prism layer of a prism sheet is formed of an elastic material, damage to the prism layer by the prism protection sheet may be effectively prevented.
  • the present invention provides a backlight unit assembly, which comprises a prism protection sheet capable of compensating for a view angle and ensuring a uniform outer appearance while satisfying front-surface brightness .
  • the present invention provides an optical sheet assembly for a backlight unit, which comprises a prism sheet having a prism layer able to effectively prevent damage from the prism protection sheet.
  • a prism protection sheet in contact with a prism layer, comprising a substrate film, and protection layers formed on both surfaces of the substrate film using a composition containing light-diffusing particles and a binder, wherein a protection layer in contact with the prism layer has higher haze than that of a surface protection layer.
  • the protection layer in contact with the prism layer may have haze of 10-70%, and the surface protection layer may have haze of 5 ⁇ 60%. In the protection sheet according to the present invention, the protection layer in contact with the prism layer may have a difference in haze of 5 ⁇ 60% from the surface protection layer.
  • the protection sheet according to the present invention may have haze of 15 ⁇ 100%.
  • a backlight unit assembly comprising the prism protection sheet.
  • a backlight unit assembly comprising at least one prism sheet including a substrate film and a prism layer, which is formed on one surface of the substrate film using an elastic polymer material having light transmittance and has a plurality of three- dimensional structures which are arranged in a repeating pattern; and a prism protection sheet in contact with the prism layer, wherein the prism protection sheet has a substrate film and protection layers formed on both surfaces of the substrate film using a composition containing light-diffusing particles and a binder, in which a protection layer in contact with the prism layer has higher haze than that of a surface protection layer.
  • the protection layer of the prism protection sheet, in contact with the prism layer may have haze of 10 ⁇ 70%, and the surface protection layer thereof may have haze of 5 ⁇ 60%.
  • the prism protection sheet may have a difference in haze between the protection layer in contact with the prism layer and the surface protection layer of 5-60% .
  • the prism protection sheet may have haze of 15-100%.
  • the prism layer of the prism sheet may have an elastic modulus of 0.05 ⁇ L00 kg/mm 2 .
  • the prism layer of the prism sheet may be formed of one or more polymer materials selected from among polyurethane, styrene-butadiene copolymers, polyacrylate, polymethacrylate, polymethylmethacrylate, polyethylene terephthalate elastomers, polyisoprene, and polysilicone.
  • the prism protection sheet in a prism protection sheet having a substrate film and protection layers formed on both surfaces of the substrate film using a composition solution containing light-diffusing particles and a binder, when the protection layer in contact with the prism layer is constructed to have haze higher than that of the surface protection layer, the light-scattering properties of the protection layer, which is in contact with the prism layer, are further increased, thereby increasing the contrast ratio and widening the view angle.
  • the prism protection sheet can be effectively used for a backlight unit assembly for LCDs, such as LCD monitors, notebook computers, TVs, PDAs, word processors, mobile phones, and games, requiring a wide view angle and a high contrast ratio while maintaining appropriate brightness .
  • a backlight unit assembly includes a prism sheet having a prism layer formed of an elastic material and a prism protection sheet in contact with the prism layer, in which the prism protection sheet has a substrate film and protection layers formed on both surfaces of the substrate film using a composition containing light-diffusing particles and a binder.
  • the protection layer in contact with the prism layer has haze higher than that of the surface protection layer, the light-scattering properties of the protection layer in contact with the prisms are further increased, thus increasing the contrast ratio, widening the view angle, and preventing damage to the prism layer.
  • FIG. 1 is a cross-sectional view illustrating a normal type backlight unit assembly for notebook computers
  • FIG. 2 is a cross-sectional view illustrating an edge type backlight unit assembly
  • FIG. 3 is a cross-sectional view illustrating a direct type backlight unit assembly
  • FIG. 4 is a cross-sectional view illustrating a conventional prism protection sheet
  • FIG. 5 is a cross-sectional view illustrating another conventional prism protection sheet
  • FIG. 6 is a cross-sectional view illustrating a prism protection sheet according to the present invention.
  • FIG. 7 is a cross-sectional view illustrating a conventional optical sheet assembly for a backlight unit
  • FIG. 8 is a cross-sectional view illustrating another conventional optical sheet assembly for a backlight unit
  • FIG. 9 is a cross-sectional view illustrating an optical sheet assembly for a backlight unit according to the present invention.
  • FIG. 10 is a schematic view illustrating an experiment for checking the extent of damage to the prism layer by the protection sheet
  • FIG. 11 is an SEM image illustrating damage to a general prism sheet by the protection sheet in the optical sheet assembly for a backlight unit
  • FIG. 12 is an SEM image illustrating no damage to the elastic prism sheet by the protection sheet in the optical sheet assembly for a backlight unit.
  • reflection sheet 2 light guide plate 3: diffusion sheet 3': diffusion plate 4, 4': prism sheet 5: protection sheet 6 : lamp
  • a prism protection sheet for use in an assembly constituting a backlight unit is provided.
  • a prism sheet basically functions to increase the front-surface brightness of a backlight unit, and a protection sheet is provided thereon in order to increase the view angle and ensure a uniform outer appearance.
  • the view angle is increased more by the light- scattering degree of the layer of the protection sheet in contact with the prisms than by that of the surface layer of the protection sheet.
  • the prism protection sheet has a substrate film and protection layers on both surfaces of the substrate film using a composition solution containing light-diffusing particles and a binder, in which the haze of the protection layer, which is in contact with the prisms, is higher than that of the surface protection layer.
  • the contrast ratio is increased and the view angle is widened.
  • the haze may be adjusted depending on the degree of roughness of the surface structure.
  • exemplary are methods of using particles having a large or small size or in a large amount in order to increase the amount of particles protruding from the surface.
  • the method of adjusting the haze is not limited thereto.
  • the prism protection sheet is illustrated in FIG. 6.
  • particles 50 having a large size are used for the lower surface of a substrate film 5001, that is, a protection layer 5003, which is in contact with the prisms
  • particles 50' having a small size are used for the upper surface of the substrate film 5001, that is, a surface protection layer 5002, thereby generating a difference in haze between the upper surface and the lower surface.
  • the protection layer 5003 in contact with the prisms causes light that has passed through the prisms to be diffused, and the surface protection layer 5002 causes such diffused light to be transmitted within a predetermined angular range.
  • the contrast ratio is increased and the view angle is widened.
  • the haze of the protection layer in contact with the prisms when the haze of the protection layer in contact with the prisms is lower than that of the surface protection layer, light passed through the prisms is transmitted within a predetermined angular range, and such transmitted light is diffused through the surface protection layer 5002. Thereby, the contrast ratio is decreased and the view angle is decreased.
  • the haze of the protection layer 5003 in contact with the prisms may be 10-70%, and the haze of the surface protection layer 5002 may be 5-60%.
  • the haze of the protection layer 5003 in contact with the prisms should be higher than that of the surface protection layer 5002. If not, when the haze of the protection layer 5003 in contact with the prisms is too low, the view angle and the contrast ratio may be decreased. Conversely, when the haze thereof is too high, brightness may be reduced. Further, the haze of the surface protection layer 5002 should be lower than that of the protection layer 5003 in contact with the prisms. However, when the haze is too low, visual defects may occur due to surface reflections. Conversely, when the haze is too high, brightness may be decreased.
  • the haze of the protection layer 5003 in contact with the prisms is controlled to be higher than that of the surface protection layer 5002, provided that the difference in haze therebetween is on the order of 5-60%.
  • the total haze of the prism protection sheet 5 falls in the range of 15-100%.
  • the prism protection sheet according to the present invention in the case where the haze of the protection layer 5003 in contact with the prisms is increased, problems in which the above protection layer wears down the peaks of the prism sheet, attributable to friction with the peaks of the prism sheet, may be caused, but are not particularly severe, because such problems may be prevented by appropriately changing the material for the prism sheet.
  • Korean Unexamined Patent Publication No. 2005-0099288 discloses a prism sheet, the prism layer of which is composed of a transparent and elastic polymer material, thereby preventing the surface of the prisms from being damaged.
  • a prism sheet is used, even when large particles are used to increase the haze of the protection layer 5003 in contact with the prisms, damage to the prism peaks may be prevented.
  • the substrate film comprises polyolefin resin, polyester resin, polyacrylic resin, or polycarbonate resin, all of which are very transparent.
  • polyester resin which is very transparent and has good mechanical strength and high processability to thus exhibit high durability to light and heat generated from a backlight unit.
  • a polyethylene terephthalate film may be used.
  • the protection layers 5002, 5003 (FIG. 6) provided on both surfaces of the substrate film are formed using a composition solution containing light-diffusing particles and a binder, and the light-diffusing particles include organic or inorganic particles .
  • the inorganic particles include silica, zirconia, calcium carbonate, barium sulfate, and titanium oxide
  • the organic particles include homopolymers or copolymers obtained from monomers, such as styrene, melamine formaldehyde, benzoguanamine formaldehyde, benzoguanamine melamine formaldehyde, propylene, ethylene, silicone, urethane, and methylmethacrylate, which may be used in a monodispersed or polydispersed form, but the present invention is not limited thereto.
  • the binder include thermosetting or UV curable resin, such as polyvinyl resin, acrylic resin, polyester resin, styrene resin, alkyd resin, amino resin, polyurethane resin
  • composition solution containing the light- diffusing particles and the binder is applied on both surfaces of the substrate film, and is then dried, thereby manufacturing the prism protection sheet.
  • the process of applying the composition solution containing the light-diffusing particles and the binder is not particularly limited, as long as it is typically known in the art.
  • an air knife process, a gravure process, a Meyer bar process, a reverse roll process, or a spray process may be conducted.
  • a backlight unit assembly including the prism protection sheet as described above is provided, which is illustrated in FIG. 9.
  • the elastic prism sheet 1004 includes a substrate film and a prism layer formed on one surface of the substrate film, in which the prism layer is formed of an elastic polymer material, and preferably, a polymer material having an elastic modulus of 0.05-100 kg/mm 2 .
  • the polymer material for the prism layer is not particularly limited, as long as it is an elastic material which is transparent and satisfies the above elastic modulus, and examples thereof include polyurethane, styrene-butadiene copolymers, polyacrylate, polymethacrylate, polymethylmethacrylate, polyethylene terephthalate elastomers, polyisoprene, or polysilicone.
  • the prism layer includes a plurality of three- dimensional structures, which are arranged in a repeating pattern, and the cross-section of which is trigonal or polygonal and preferably has a right isosceles triangle shape .
  • the substrate film may be the same as or different from that of the prism protection sheet, and examples thereof include polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, polymethacrylate, polymethylmethacrylate, polyacrylate, polyimide, or polyamide.
  • the substrate film further includes light-diffusing particles to thus exhibit a roughened structure.
  • the backlight unit assembly of the present invention may further include other optical sheets typically used for LCDs.
  • a light guide plate, a reflection sheet, and a diffusion sheet may be used depending on the type of backlight unit as shown in FIGS. 1 to 3, but the present invention is not limited thereto.
  • Substrate Film PET film (Kolon, thickness 188 ⁇ m)
  • Light-Diffusing Particles Polymethylmethacrylate (monodispersed and polydispersed particles)
  • Binder Resin Polyester or acrylic resin (Kolon)
  • a composition solution containing light-diffusing particles and a binder was applied through gravure coating on one surface of a substrate film, and was then dried at 100 ° C for 3 min, thus forming a surface protection layer (dry thickness of 5-30 ⁇ m) , after which a protection layer (in contact with prisms, dry thickness of 5-30 ⁇ m) was formed on the other surface thereof in the same manner.
  • Respective prism protection sheets were manufactured using the above material and method, while adjusting the haze of the surface protection layer and the haze of the protection layer in contact with the prisms, as shown in Table 1 below. As such, haze was measured using a hazemeter
  • a backlight unit assembly was constructed as follows. ⁇ Backlight Unit Assembly>
  • Backlight Unit 24" direct type backlight unit
  • a prism sheet having a prism layer formed of a polymer material having an elastic modulus of 0.1 kg/mm 2 was used.
  • the brightness, view angle, and front-surface contrast ratio were measured using a BM-7 (luminance calorimeter, Topcon) .
  • the results are shown in Table 2 below.
  • Example 9-16 in some cases (Examples 9-14), in which the haze of the protection layer in contact with the prisms was 10-70%, the haze of the surface protection layer was 5-60%, the difference in haze therebetween was 5-60%, and the brightness of the prism protection sheet was in the range of 15-100%, the brightness was almost the same as in Comparative Examples 7-12. Examples 17 ⁇ 24 and Comparative Examples 13 ⁇ 18
  • a backlight unit assembly was constructed in the same manner as in Examples 9-16 and Comparative Examples 7-12, with the exception that an elastic prism sheet having a prism layer formed of a polymer material having an elastic modulus of 60 kg/mm 2 was used as the prism sheet.
  • the prism protection sheet manufactured in Example 3
  • the prism protection sheet was moved rightward at a rate of 500 mm/min while a load of 200 g was applied thereto, and then the prism sheet thereunder was observed using an SEM.
  • FIG. 11 the same experiment was conducted using the elastic prism sheet of the examples. The results are shown in FIG. 12.
  • the SEM image of FIG. 11 showed that the prism peaks were considerably damaged, whereas the SEM image of FIG. 12 showed that there was no damage to the prism peaks. From this, the case of the optical sheet assembly for a backlight unit using the elastic prism sheet could be seen to be preferable in terms of preventing damage from the surface of the prism protection sheet in contact with the prisms.

Abstract

L'invention concerne une feuille de protection de prisme qui est une feuille optique à placer sur une surface pour former des prismes correspondant à une surface de sortie de lumière d'une feuille prismatique, et un ensemble unité de rétro-éclairage comprenant ladite feuille de protection. Dans la feuille de protection de prisme, des couches de protection sont formées sur les deux surfaces d'un film substrat utilisant une solution d'une composition contenant des particules de diffusion de lumière et un liant, la couche de protection en contact avec les prismes présentant un voile plus important que celui de la couche de protection de surface, ce qui permet d'augmenter les propriétés de diffusion de lumière de la couche de protection en contact avec les prismes, entraînant ainsi un rapport de contraste élevé et un angle de visualisation élargi. La feuille de protection de prisme est efficacement utilisée pour construire un ensemble unité de rétro-éclairage destiné à des LCD, tels que des moniteurs de LCD, des ordinateurs bloc-notes, des TV, des PDA, des processeurs de mots, des téléphones mobiles et des jeux nécessitant un angle de visualisation élargi et un rapport de contraste élevé tout en maintenant une brillance appropriée, l'ensemble unité de rétro-éclairage comprenant ladite feuille de protection de prisme.
PCT/KR2008/000819 2007-02-13 2008-02-12 Feuille de protection de prisme et ensemble unité de rétro-éclairage WO2008100057A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN2008800047689A CN101627324B (zh) 2007-02-13 2008-02-12 用于棱镜与背光模块总成的覆盖片

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR10-2007-0014677 2007-02-13
KR10-2007-0014676 2007-02-13
KR1020070014676A KR100988766B1 (ko) 2007-02-13 2007-02-13 백라이트용 광학시트 어셈블리
KR1020070014677A KR100869474B1 (ko) 2007-02-13 2007-02-13 프리즘 보호시트

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WO2008100057A1 true WO2008100057A1 (fr) 2008-08-21

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WO (1) WO2008100057A1 (fr)

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CN101995704A (zh) * 2009-08-05 2011-03-30 乐金显示有限公司 散射片及具有该散射片的液晶显示器件
WO2011049751A1 (fr) * 2009-10-23 2011-04-28 3M Innovative Properties Company Constructions optiques et procédé de fabrication de celles-ci
EP2686896A2 (fr) * 2011-03-17 2014-01-22 3M Innovative Properties Company Films d'extraction de lumière de diode électroluminescente organique (oled) qui comprennent des nanoparticules et des structures périodiques
WO2016172428A1 (fr) * 2015-04-24 2016-10-27 3M Innovative Properties Company Film optique
CN108279452A (zh) * 2017-12-28 2018-07-13 重庆市中光电显示技术有限公司 背光模组和应用于背光模组的扩散片

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JP6559069B2 (ja) * 2012-12-10 2019-08-14 ジーティーエイティー コーポレーションＧｔａｔ Ｃｏｒｐｏｒａｔｉｏｎ 多層サファイアカバープレートを含有してなる携帯用電子機器

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US20060142448A1 (en) * 2004-12-27 2006-06-29 Samsung Electronics Co., Ltd. Brightness enhancement film and a method of manufacturing thereof
EP1726976A1 (fr) * 2005-05-24 2006-11-29 LG Electronics Inc. Feuille à prismes et unité de rétroéclairage la comprenant

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US20060142448A1 (en) * 2004-12-27 2006-06-29 Samsung Electronics Co., Ltd. Brightness enhancement film and a method of manufacturing thereof
EP1726976A1 (fr) * 2005-05-24 2006-11-29 LG Electronics Inc. Feuille à prismes et unité de rétroéclairage la comprenant

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101995704A (zh) * 2009-08-05 2011-03-30 乐金显示有限公司 散射片及具有该散射片的液晶显示器件
CN101995704B (zh) * 2009-08-05 2013-07-03 乐金显示有限公司 散射片及具有该散射片的液晶显示器件
US8755004B2 (en) 2009-08-05 2014-06-17 Lg Display Co., Ltd. Liquid crystal display device comprising a second diffusion sheet having upper and lower diffusion layers wherein the upper diffusion layer includes multi-dispersed beads
WO2011049751A1 (fr) * 2009-10-23 2011-04-28 3M Innovative Properties Company Constructions optiques et procédé de fabrication de celles-ci
US9022619B2 (en) 2009-10-23 2015-05-05 3M Innovative Properties Company Optical constructions and method of making the same
EP2686896A2 (fr) * 2011-03-17 2014-01-22 3M Innovative Properties Company Films d'extraction de lumière de diode électroluminescente organique (oled) qui comprennent des nanoparticules et des structures périodiques
EP2686896A4 (fr) * 2011-03-17 2015-03-18 3M Innovative Properties Co Films d'extraction de lumière de diode électroluminescente organique (oled) qui comprennent des nanoparticules et des structures périodiques
WO2016172428A1 (fr) * 2015-04-24 2016-10-27 3M Innovative Properties Company Film optique
US10288796B2 (en) 2015-04-24 2019-05-14 3M Innovative Properties Company Optical film
CN108279452A (zh) * 2017-12-28 2018-07-13 重庆市中光电显示技术有限公司 背光模组和应用于背光模组的扩散片

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TW200900745A (en) 2009-01-01

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