CN100407007C - Light diffusion film for LCD back-light unit - Google Patents
Light diffusion film for LCD back-light unit Download PDFInfo
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- CN100407007C CN100407007C CN2004800348688A CN200480034868A CN100407007C CN 100407007 C CN100407007 C CN 100407007C CN 2004800348688 A CN2004800348688 A CN 2004800348688A CN 200480034868 A CN200480034868 A CN 200480034868A CN 100407007 C CN100407007 C CN 100407007C
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- 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
- G02B5/0236—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element
- G02B5/0242—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place within the volume of the element by means of dispersed particles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/38—Layered products comprising a layer of synthetic resin comprising epoxy resins
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- 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
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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
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Abstract
Disclosed is a light diffusion film (1) for LCD (Liquid Crystal Display) back-light unit, which comprises a light diffusion layer (2, 4) prepared by coating a composition comprising a binder resin and light diffusion beads on at least one side of a high-transparency plastic support (3), the light diffusion layer (2, 4) comprising, based on 100 parts by weight of the binder resin solid, 50 to 350 parts by weight of the light diffusion beads having an arithmetic average particle diameter of 1 to 50 um and a polydispersity index (PDI) of more than 1.00 and less than 1.50 (that is, excluding 1.00 but including 1.50) as calculated by the following Equation 1: Equation 1 Formula (1) average diameter; N is the number of beads analyzed; and di is the diameter o i beads. The light diffusion film (1) of the present invention, when installed in a back-light unit, guarantees an enhanced luminance relative to the existing products.
Description
Technical field
The present invention relates to the high-luminance light diffuser of a kind of LCD of being used for (LCD) back light unit.More specifically, the present invention relates to a kind of light-diffusing film: the organic bead of transparent sphere is scattered in is used for skin hardness and is bonded to epilamellar clear binder resin such as the acrylic resin that forms by high grade of transparency plastics, be used in the one or both sides of the dispersion bead coated substrate film in the adhesive resin then by the preparation of following method.
Background technology
Because the development of the innovative of display technology, enlarge screen, more low power consuming and more the LCD of high brightness be the TFT-LCD core technology in future.In order to adapt to these requirements, to the parts of TFT-LCD, promptly Liquid Crystal Module and back light unit have carried out many researchs.
Enlarge screen, more low power consuming and more high brightness back light unit also with the trial of eliminating back light unit itself in development.But, because the fundamental characteristics of LCD can not form the LCD display that does not have independent light source such as LED unit in the present technology.
In back light unit, the function of light-diffusing film is with from the beam spread as the lamp in the sidelight source on face that is installed in LCD on whole of the screen or the back, and this refraction of optical beam is become uniform beam on the frontal.In addition, reflectance coating, optical plate and prism film being used for LCD operates accordingly.Decay gradually by above-mentioned different medium from the light intensity that light emitted is come, so the brightness on the actual screen of watching of user only is from more than one percent of the light intensity of original light source.
For head it off, taked thousand and one way, for example comprise, improve the brightness of light source, or reduce the thickness of optical plate, diffusion barrier, prism and every kind of medium of diffuser plate.But the thickness that reduces every kind of medium is owing to the throughput rate and the operating efficiency of manufacturer are restricted.
Recently attempted the thousand and one way of the pattern of change optical plate formation.For example, with bead, will be used for spreading equably light beam on base material film by the light-diffusing film that the coating optical diffusion layer prepares with excellent light diffusion efficient.In this connection, taked to be used for the thousand and one way of high brightness, having comprised: the selection of bead, the antireflection of the control of coating thickness and posterior membrane coating.
In light-diffusing film, optical diffusion layer has the composition of the light diffusion bead that is included in the adhesive resin.The light diffusion bead that is used for this purpose comprises the organic polymer bead of light diffusion efficient excellence.But, aspect the type of organic polymer bead, there is restriction, described organic polymer bead is mainly by emulsion polymerization prepared.On the other hand, inorganic bead and adhesive resin are incompatible, and light diffusion efficient is poor at present.
According to purposes, differently developed the light-diffusing film that is used for pen meter this formula computing machine and is used for the LCD monitor, because the light-diffusing film that is used for this formula of pen meter computing machine has the back light unit of different structure, therefore has the optical property that is different from the light-diffusing film that is used for the LCD monitor.Although identical construction is not used for all products, but the back light unit that is used for this formula of pen meter computing machine comprises: the brightness enhancement film on single light-diffusing film and at the coverlay of brightness enhancement film, and the back light unit that is used for the LCD monitor comprises two light-diffusing films and dual brightness reinforcing membrane on light-diffusing film or diffuse reflective polarizer film.
Light-diffusing film in the back light unit that the LCD monitor is used comprises: in the optical diffusion layer composition, adhesive resin based on 100 weight portions, the diameter of 150 to 350 weight portions is greater than the bead of 20 μ m, so the coating thickness of optical diffusion layer is big, wherein difference is big aspect the total light transmittance of positive and back.On the other hand, light-diffusing film in the back light unit that this formula of pen meter computing machine is used comprises: in the optical diffusion layer composition, adhesive resin based on 100 weight portions, the bead of the about 10 μ m of the diameter of 50 to 250 weight portions, so the coating of optical diffusion layer is thin, wherein difference is relative less aspect the total light transmittance of front and back.
Recent trend is to need the parts of high brightness indicator spare that high brightness is provided to all.Brightness decay behind back light unit about 1/10th to from the original brightness of single lamp, and under the situation of liquid crystal board further is reduced to one of one of the percentage of original brightness or two percentages.It is a serious thing of paying close attention to that the raising of brightness is carried out for the image of LCD device.For this reason, require LCD manufacturer to design the trial of the LCD with high opening ratio, described aperture efficiency has been in the upper limit, and manufacturer backlight attempts reducing the thickness of back light unit.
An example that relates to the conventional method of light-diffusing film is the open No.2001-054274 of Korean Patent, this patent disclosure a kind of light-diffusing film with optical diffusion layer, described optical diffusion layer comprises inorganic or organic light diffusion body and transparent adhesives resin, and this optical diffusion layer is to form on any side of the basement membrane that comprises the transparent polymeric resin film.In light-diffusing film, optical diffusion layer contains the condensed particles size less than 50 μ m and pile up ratio less than 10% bead.
Summary of the invention
Therefore, the present inventor finds, be used for the high-luminance light diffuser of LCD back light unit, the polydispersity index (PDI) that records according to the degree of disperseing is greater than 1.00 and be not more than bead guarantee that 1.50 the application of monodispersity bead in the optical diffusion layer composition can be by the using less amount high brightness from light source, thereby has finished the present invention.
Therefore, one object of the present invention is to provide a kind of light-diffusing film with optical diffusion layer, and its bead with less amount provides the high brightness from light source.
In order to reach purpose of the present invention, a kind of light-diffusing film is provided, it comprises by the composition that will comprise adhesive resin and light diffusion bead and is coated on the optical diffusion layer that at least one side of high grade of transparency plastic carrier prepares.This optical diffusion layer comprises, adhesive resin solid based on 100 weight portions, the light diffusion bead of 50 to 350 weight portions, wherein the arithmetic mean particle diameter of this light diffusion bead is 1 to 50 μ m, and as with the polydispersity index (PDI) of following equation 1 calculating greater than 1.00 and be not more than 1.50:
Equation 1
Polydispersity index
Wherein
Dn is a number average diameter; Dw is a weighted average diameter; N is analyzed number of beads; Di is the diameter of bead i.
Below, the present invention will be described in further detail.
Xsect according to light-diffusing film 1 of the present invention is shown among Fig. 1.Light-diffusing film 1 has the optical diffusion layer 2 and 4 on the one side of high grade of transparency plastic carrier 3 or two faces, and described diffusion layer 2 and 4 comprises adhesive resin and light diffusion bead.
Being described in further detail below of individual layers.
(1) optical diffusion layer
The optical diffusion layer that forms on the one side of high grade of transparency plastic carrier or two faces comprises adhesive resin and light diffusion bead.Optical diffusion layer not only relates to incident scattering of light, reflection and refraction, with diffused light, but also produces the more light of high transmission rate, with light by light guide plate equably diffusion on the whole surface of lcd screen.
Herein, optical diffusion layer use to the bounding force of plastic carrier and with all excellent adhesive resin of compatibility as the bead of light diffusing agent.The instantiation of the resin of Shi Yonging can comprise herein: unsaturated polyester (UP); Acrylic resin, for example polymkeric substance or the multipolymer or the terpolymer of methyl methacrylate, Jia Jibingxisuanyizhi, isobutyl methacrylate, n-BMA, methacrylic acid normal-butyl methyl esters, acrylic acid, methacrylic acid, methacrylic acid hydroxyl ethyl ester, methacrylic acid hydroxyl propyl ester, Hydroxyethyl Acrylate, acrylamide, n-methylolacrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate or acrylic acid-2-ethyl caproite; Carbamate; Epoxy resin; Or melamine.If desired, can use rigidizer to come hardening resin to film, purpose is to improve thermotolerance, wearing quality and adhesiveness.Preferred resin has high transmittance, particularly, basement membrane is had high adhesiveness, because it forms optical diffusion layer.
The light diffusion bead comprises various organic or inorganic beads, and it improves transmittance and diffusion rate, and its refractive index and ordinary resin have difference.The instantiation of the light diffusion bead of Shi Yonging can comprise herein: organic bead, (for example comprise the acrylic compounds bead, methyl methacrylate, Jia Jibingxisuanyizhi, isobutyl methacrylate, n-BMA, methacrylic acid normal-butyl methyl esters, acrylic acid, methacrylic acid, methacrylic acid hydroxyl ethyl ester, methacrylic acid hydroxyl propyl ester, Hydroxyethyl Acrylate, acrylamide, n-methylolacrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, the polymkeric substance of n-butyl acrylate or acrylic acid-2-ethyl caproite or multipolymer or terpolymer), the olefines bead (for example, tygon, polystyrene or polypropylene), acryloyl group-olefin copolymer is perhaps by forming the single polymers bead and being coated with the multilayer polycomponent bead that different monomers prepares in the bead layer; And the bead of mineral-type, as monox, aluminium oxide, titanium dioxide, zirconia or magnesium fluoride.The present invention preferably uses organic bead, and it has excellent light diffusion efficient with respect to inorganic bead.
Based on the adhesive resin solids content of 100 weight portions, the content of light diffusion bead is preferably in the scope of 50 to 350 weight portions.The content that is lower than the light diffusion bead of 50 weight portions has worsened light diffusion efficient, and the light diffusion bead content that surpasses 350 weight portions causes the white turbidity that caused by the bead of piling up, use the light diffusion bead aspect have difficulty.Above-mentioned scope can represent with the bead quantity in the unit area optical diffusion layer, i.e. about 10 to 200 beads in the area of 100 μ m * 100 μ m.
The bead number is less than 10, the light diffusion degradation in efficiency.The bead number surpasses 200, has improved the quantity of meticulous bead relatively, thereby has improved polydispersity index, and caused bead to be piled up, and makes the light diffusion degradation in efficiency.
Use the particle size analysis instrument of making by Fritsch Company: ANALYSETTE22 to measure the average-size of bead.The arithmetic mean particle diameter of measuring with the particle size analysis instrument is preferably in the scope of 1 to 50 μ m.Arithmetic mean particle diameter less than 1 μ m causes the light diffusion degradation in efficiency, and the arithmetic mean particle diameter that surpasses 50 μ m has increased the thickness of optical diffusion layer, is difficult to optical diffusion layer is installed in the product that thickness reduces.More preferably the arithmetic mean particle diameter is in the scope of 5 to 30 μ m.
Light-diffusing film that the present invention develops uses polydispersity index greater than 1.00 and be not more than single bead that disperses of 1.50 as the light diffusion bead, to use the bead exhibit high brilliance than existing product less amount.The brightness that is installed in the light-diffusing film in the back light unit is to be determined by the particle ratio of optical diffusion layer and distribution of particles.
Polydispersity index calculates according to equation 1, and particularly, is to use FE-SEM (Field Emission Scanning Electronic Microscope; Make by Hitachi Company) with 500 times enlargement factors, by the analysis to measure of particle diameter distribution.More specifically, will get with N the bead that FE-SEM observes and make sample, and measure diameter, with definite number average diameter Dn, and weighted average diameter Dw, and according to equation 1 calculating polydispersity index.For complete single bead that disperses, polydispersity index is 1.00, so, when use polydispersity index greater than 1.00 and be not more than 1.50 single when disperseing bead rather than polydispersity index greater than 1.50 bead, the bead ratio is low more, the brightness of light source is big more.More preferably the polydispersity index of bead is greater than 1.00 and be not more than 1.40.
At Colloid Polym.Sci.
1999, in the 210th to 216 page, will be defined as by the polydispersity index that equation 1 provides and be used to assess single tolerance of disperseing the bead degree of scatter.
The bead compositions that has this distribution of particles in the high-luminance light diffusing layer must be dispersed on the whole surface of plastic carrier.The light diffusion solution of preparation thus is coated on the plastic carrier by comma cutter (comma knife) or photogravure.Film thickness is aptly in the scope of 5 to 50 μ m.Employing is less than the film thickness of 5 μ m, and the bead that can not so distribute is to provide light diffusion characteristic.The film thickness that adopt to surpass 50 μ m can not be installed in optical diffusion layer in the product that thickness reduces.
(2) plastic carrier
Any transparent carrier can be used for optical diffusion layer is coated with plastic carrier on it.The instantiation of plastic carrier can comprise: polycarbonate, polypropylene, polyethylene terephthalate, tygon, epoxy resin etc.Preferred plastic carrier is a polyethylene terephthalate.Recently, the polyethylene terephthalate that will have the UV shield effectiveness is used for optical diffusion layer, and does not add the UV stabilizing agent.But this is Yan Taigui to being used for commercial the application.
Require plastic carrier that the bounding force of optical diffusion layer to adhesive resin is provided, and the effect that optical diffusion layer is not caused by its high transmission rate, and have surface flatness, and do not have the deviation of brightness.
The thickness of plastic carrier is suitably 50 to 250 μ m, more preferably 75 to 200 μ m.The thickness that is lower than 50 μ m causes the mechanical property and the poor heat resistance of light-diffusing film, and above the thickness of 250 μ m product is thickened, and causes the problem aspect the installation in the product that thickness reduces.
The accompanying drawing summary
Fig. 1 is the cross-sectional view according to light-diffusing film of the present invention.
Implement best mode of the present invention
Below, will describe the present invention in detail in the mode of following embodiment, described embodiment is not an intended scope of the present invention.
In the following embodiments, use the particle size analysis instrument of making by Fritsch Company: the arithmetic mean particle diameter and the polydispersity index of ANALYSETTE22 measuring light diffusion bead.
Embodiment 1
With the dilution with toluene of 100 parts by weight of acrylic resin 52-666 (by Aekyung Chemical, Company supplies with) with the methyl ethyl ketone and 100 weight portions of 100 weight portions.With respect to the adhesive resin solids content, with 120 weight portion arithmetic mean particle diameters is that 12.7 μ m and polydispersity index are 1.046 the polymethylmethacrylate bead PX010 (being supplied with by Kolon Company) of (measuring according to the particle size analysis instrument of being made by Fritsch Company: ANALYSETTE22) is added in the adhesive resin, and disperse with muller (Dynomill), obtain light diffusion solution.Then, with photogravure this light diffusion solution is applied to the thickness of 10 to 30 μ m the ultra-high transparency of 100 μ m thickness polyethylene terephthalate film (T600, by Mitsubishi Company supply with) one side or two-sided on, finish light-diffusing film.
With the dilution with toluene of 100 parts by weight of acrylic resin 52-666 (by Aekyung Chemical, Company supplies with) with the methyl ethyl ketone and 100 weight portions of 100 weight portions.With respect to the adhesive resin solids content, with 130 weight portion arithmetic mean particle diameters is that 14.2 μ m and polydispersity index are 1.136 the polymethylmethacrylate bead PX010 (being supplied with by Kolon Company) of (measuring according to the particle size analysis instrument of being made by Fritsch Company: ANALYSETTE22) is added in the adhesive resin, and disperse with muller (Dynomill), obtain light diffusion solution.Then, with photogravure this light diffusion solution is applied to the thickness of 10 to 30 μ m the ultra-high transparency of 100 μ m thickness polyethylene terephthalate film (T600, by Mitsubishi Company supply with) one side or two-sided on, finish light-diffusing film.
With the dilution with toluene of 100 parts by weight of acrylic resin Surcol836 (supplying with) with the methyl ethyl ketone and 100 weight portions of 100 weight portions by Allied Colloids Company.With respect to the adhesive resin solids content, with 100 weight portion arithmetic mean particle diameters is that 11.5 μ m and polydispersity index are 1.310 the polymethylmethacrylate bead PX010 (being supplied with by Kolon Company) of (measuring according to the particle size analysis instrument of being made by Fritsch Company: ANALYSETTE22) is added in the adhesive resin, and disperse with muller (Dynomill), obtain light diffusion solution.Then, with photogravure this light diffusion solution is applied to the thickness of 10 to 30 μ m the ultra-high transparency of 100 μ m thickness polyethylene terephthalate film (A4300, by Toyobo Company supply with) one side or two-sided on, finish light-diffusing film.
Embodiment 4
With the dilution with toluene of 100 parts by weight of acrylic polyvalent alcohol BR-113 (by Mitsubishi, Rayon Company supplies with) with the methyl ethyl ketone and 10 weight portions of 100 weight portions.With respect to the adhesive resin solids content, with 110 weight portion arithmetic mean particle diameters is that 9.8 μ m and polydispersity index are 1.272 the polymethylmethacrylate bead PX010 (being supplied with by Kolon Company) of (measuring according to the particle size analysis instrument of being made by Fritsch Company: ANALYSETTE22) is added in the adhesive resin, and disperse with muller (Dynomill), obtain light diffusion solution.Then, with photogravure this light diffusion solution is applied to the thickness of 10 to 30 μ m the ultra-high transparency of 100 μ m thickness polyethylene terephthalate film (A4300, by Toyobo Company supply with) one side or two-sided on, finish light-diffusing film.
Comparative example 1
With the dilution with toluene of 100 parts by weight of acrylic polyvalent alcohol BR-113 (by Mitsubishi, Rayon Company supplies with) with the methyl ethyl ketone and 100 weight portions of 100 weight portions.With respect to the adhesive resin solids content, with 150 weight portion arithmetic mean particle diameters is that 13.5 μ m and polydispersity index are 1.698 the polymethylmethacrylate bead PX010 (being supplied with by Kolon Company) of (measuring according to the particle size analysis instrument of being made by Fritsch Company: ANALYSETTE22) is added in the adhesive resin, and disperse with muller (Dynomill), obtain light diffusion solution.Then, with photogravure this light diffusion solution is applied to the thickness of 10 to 30 μ m the ultra-high transparency of 100 μ m thickness polyethylene terephthalate film (A4300, by Toyobo Company supply with) one side or two-sided on, finish light-diffusing film.
Comparative example 2
With the dilution with toluene of 100 parts by weight of acrylic polyvalent alcohol Surcol836 (supplying with) with the methyl ethyl ketone and 100 weight portions of 100 weight portions by Allied Colloids Company.With respect to the adhesive resin solids content, with 170 weight portion arithmetic mean particle diameters is that 12.2 μ m and polydispersity index are 1.716 the polymethylmethacrylate bead PX010 (being supplied with by Kolon Company) of (measuring according to the particle size analysis instrument of being made by Fritsch Company: ANALYSETTE22) is added in the adhesive resin, and disperse with muller (Dynomill), obtain light diffusion solution.Then, with photogravure this light diffusion solution is applied to the thickness of 10 to 30 μ m the ultra-high transparency of 100 μ m thickness polyethylene terephthalate film (A4300, by Toyobo Company supply with) one side or two-sided on, finish light-diffusing film.
Comparative example 3
With the dilution with toluene of 100 parts by weight of acrylic polyvalent alcohol 52-666 (by Aekyung Chemical, Company supplies with) with the methyl ethyl ketone and 100 weight portions of 100 weight portions.With respect to the adhesive resin solids content, with 150 weight portion arithmetic mean particle diameters is that 10.6 μ m and polydispersity index are 1.724 the polymethylmethacrylate bead PX010 (being supplied with by Kolon Company) of (measuring according to the particle size analysis instrument of being made by Fritsch Company: ANALYSETTE22) is added in the adhesive resin, and disperse with muller (Dynomill), obtain light diffusion solution.Then, with photogravure this light diffusion solution is applied to the thickness of 10 to 30 μ m the ultra-high transparency of 100 μ m thickness polyethylene terephthalate film (A4300, by Toyobo Company supply with) one side or two-sided on, finish light-diffusing film.
Comparative example 4
With the dilution with toluene of 100 parts by weight of acrylic polyvalent alcohol 52-666 (by Aekyung Chemical, Company supplies with) with the methyl ethyl ketone and 100 weight portions of 100 weight portions.With respect to the adhesive resin solids content, with 150 weight portion arithmetic mean particle diameters is that 11.7 μ m and polydispersity index are 1.952 the polymethylmethacrylate bead PX010 (being supplied with by Kolon Company) of (measuring according to the particle size analysis instrument of being made by Fritsch Company: ANALYSETTE22) is added in the adhesive resin, and disperse with muller (Dynomill), obtain light diffusion solution.Then, with photogravure this light diffusion solution is applied to the thickness of 10 to 30 μ m the ultra-high transparency of 100 μ m thickness polyethylene terephthalate film (A4300, by Toyobo Company supply with) one side or two-sided on, finish light-diffusing film.
According to following measuring method, analyze the brightness and the total light transmittance of the light-diffusing film for preparing in embodiment and the comparative example.
(1) particle size distribution on the optical diffusion layer of light-diffusing film
The S-4300FESEM (Field EmissionScanning Electronic Microscope) that use is made by Hitachi Company, adopt the optical diffusion layer of 500 times enlargement factor observation light-diffusing film, be distributed in the diameter d i of all beads in 100 μ m * 100 μ m areas and the quantity N of bead with measurement.Then, according to the number average diameter and the weighted average diameter of equation 1 calculating bead, to determine polydispersity index.
(2) particle size distribution of bead
Use the particle size analysis instrument LS-13320 that makes by Beckman Coulter Company, use wavelength to be the laser of 750nm and 90 seconds 5W output, measure the number-average molecular weight and the weight-average molecular weight of bead, to calculate the polydispersity index of bead.
(3) brightness
The cutting light-diffusing film to be being installed in the back light unit, and measures the brightness under the light-diffusing film on the optical plate of back light unit.Then, optical diffusion layer and dual brightness reinforcing membrane are being installed (by the Vikuiti of 3M Company supply with brightness measurer (by the BM7 of TOPCON Company supply) at 9 point measurements
TMDBEF-D440) or the diffuse reflective polarizer film (Vikuiti that supplies with by 3M Company
TMDRPF) brightness after.
(4) total light transmittance (TT) and mist degree
Employing is installed in the 40mm * 40mm membrane sample in the back light unit, with two kinds of mist degree measuring instruments: the NDH2000 and the COH300A that make by Nippon Denshoku Company, in front from the light beam of light emitted from membrane sample to the back side by the time and light beam from the back-to-front of membrane sample by the time, measure total light transmittance (TT) and mist degree.
Character according to the light-diffusing film of embodiment and comparative example is listed in the table 1.
Table 1
As from table 1 as seen, compare with comparative example 1 to 4, embodiments of the invention 1,2 and 3 provide excellent luminance.That is, adopt the brightness measurement of [(A) backlight+diffuser], [(A)+dual brightness reinforcing membrane] and [(A)+dual brightness reinforcing membrane+coverlay] to show: the brightness that the embodiments of the invention guarantee is higher than comparative example.
Commercial Application
As mentioned above, in the time of in being installed on back light unit, have the polydispersity index of containing (PDI) greater than 1.00 and be not more than single light-diffusing film of the optical diffusion layer of bead that disperses of 1.50 and compare with existing product The brightness of raising is provided.
Claims (5)
1. light-diffusing film that is used for liquid crystal display backlight unit, it comprises by the composition that will comprise adhesive resin and light diffusion bead and is coated on the optical diffusion layer that at least one side of high grade of transparency plastic carrier prepares,
This optical diffusion layer comprises, adhesive resin solid based on 100 weight portions, the light diffusion bead of 50 to 350 weight portions, wherein the arithmetic mean particle diameter of this light diffusion bead is 1 to 50 μ m, and as with the polydispersity index of following equation 1 calculating greater than 1.00 and be not more than 1.50:
Equation 1
Wherein
Dn is a number average diameter; Dw is a weighted average diameter; N is analyzed number of beads; Di is the diameter of bead i.
2. the light-diffusing film that is used for liquid crystal display backlight unit as claimed in claim 1, wherein said polydispersity index is greater than 1.00 and be not more than in 1.40 the scope.
3. the light-diffusing film that is used for liquid crystal display backlight unit as claimed in claim 1, the arithmetic mean particle diameter of wherein said light diffusion bead are 5 to 30 μ m.
4. the light-diffusing film that is used for liquid crystal display backlight unit as claimed in claim 1, the thickness of wherein said optical diffusion layer are 5 to 50 μ m.
5. the light-diffusing film that is used for liquid crystal display backlight unit as claimed in claim 1, per 100 μ m in the wherein said optical diffusion layer * 100 μ m unit areas comprise 10 to 200 beads.
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| KR1020030084316 | 2003-11-26 | ||
| KR20030084316 | 2003-11-26 | ||
| KR1020040063699 | 2004-08-13 |
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| CN100407007C true CN100407007C (en) | 2008-07-30 |
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| CN2004800348688A Expired - Fee Related CN100407007C (en) | 2003-11-26 | 2004-08-30 | Light diffusion film for LCD back-light unit |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR100988764B1 (en) * | 2007-09-07 | 2010-10-25 | 코오롱인더스트리 주식회사 | Multi-functional optic film |
| KR101291901B1 (en) * | 2009-08-05 | 2013-07-31 | 엘지디스플레이 주식회사 | Liquid crystal display device |
| CN101979914A (en) * | 2010-09-21 | 2011-02-23 | 浙江池禾科技有限公司 | Optical diffusion film and backlight module using same |
| CN103982827A (en) * | 2014-05-29 | 2014-08-13 | 深圳市华星光电技术有限公司 | Backlight module and liquid crystal display |
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| US20020005924A1 (en) * | 2000-05-16 | 2002-01-17 | Kimoto Co., Ltd. | Light diffusion sheet |
| CN1339116A (en) * | 1999-02-05 | 2002-03-06 | 富士胶片株式会社 | Matlike high-transmittance film |
| WO2003005072A1 (en) * | 2001-06-30 | 2003-01-16 | Skc Co., Ltd. | Light diffusing film |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2809496B1 (en) * | 2000-05-23 | 2002-07-12 | Saint Gobain Vitrage | DIFFUSING LAYER |
| TWI276861B (en) * | 2001-03-07 | 2007-03-21 | Nitto Denko Corp | Liquid crystal cell substrate, the method of producing the same and the liquid crystal display using the same |
| JP4351456B2 (en) * | 2002-03-26 | 2009-10-28 | 恵和株式会社 | Light diffusion sheet and backlight unit using the same |
| JP4351455B2 (en) * | 2002-03-26 | 2009-10-28 | 恵和株式会社 | Light diffusion sheet and backlight unit using the same |
-
2004
- 2004-08-13 KR KR1020040063699A patent/KR100601759B1/en not_active IP Right Cessation
- 2004-08-30 CN CN2004800348688A patent/CN100407007C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1130708A (en) * | 1997-07-11 | 1999-02-02 | Keiwa Shoko Kk | Light diffusion sheet, and manufacture of back light unit using the same and light diffusion sheet |
| CN1339116A (en) * | 1999-02-05 | 2002-03-06 | 富士胶片株式会社 | Matlike high-transmittance film |
| US20020005924A1 (en) * | 2000-05-16 | 2002-01-17 | Kimoto Co., Ltd. | Light diffusion sheet |
| WO2003005072A1 (en) * | 2001-06-30 | 2003-01-16 | Skc Co., Ltd. | Light diffusing film |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20050050526A (en) | 2005-05-31 |
| CN1886692A (en) | 2006-12-27 |
| KR100601759B1 (en) | 2006-07-14 |
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