KR20200126817A - Anti-glare film and display apparatus - Google Patents

Abstract

The present invention relates to an optical laminate for a display device and a display device including the optical laminate for a display device, wherein the optical laminate for a display device comprises: a light-transmitting substrate; and a hard coating layer comprising a binder resin, organic fine particles dispersed in the binder resin, and a siloxane polymer, and a ratio of two or more organic particles that aggregate with each other among the organic fine particles is 90 to 96%. The optical laminate for a display device exhibits a high contrast ratio.

Description

Optical laminate for display device and display device {ANTI-GLARE FILM AND DISPLAY APPARATUS}

The present invention relates to an optical laminate for a display device and a display device.

As flat panel display technology develops toward large-area and high-resolution, applied products are evolving from home and office applications such as TVs, monitors, and mobiles to large-area displays such as outdoor billboards and electronic signs. Flat panel displays (FPDs) such as LCD, PDP, OLED, and rear-projection TVs, when exposed to external light such as natural light, cause fatigue or headaches to the user's eyes due to the surface reflected light. In some cases, the image created inside the display is not recognized as a clear image. In order to solve this disadvantage, an optical film for inducing internal scattering by using a refractive index between a resin forming a coating film and a fine particle is applied to scatter external light by forming irregularities on the display surface.

For this purpose, an optical film applied to a surface of a display device or the like is required not only to have an anti-glare effect, but also to have high clarity and high contrast ratio. However, in general, the higher the haze value, the greater the degree of diffusion of external light, so that the anti-glare effect is good, but there is a problem that the contrast ratio decreases due to the distortion of the image due to surface scattering and the whitening phenomenon due to internal scattering. In this way, when the sharpness and contrast ratio are increased, the anti-glare property is deteriorated, and when the anti-glare property is increased, there is a problem that the image sharpness and the contrast ratio are deteriorated.How to control such properties is in the manufacture of a high-resolution display film, It can be said to be an important skill.

An object of the present invention is to provide an optical laminate for a display device capable of preventing sparkling defects while exhibiting high contrast ratio and excellent image sharpness.

In addition, the present invention is to provide a display device including the optical laminate for a display device and exhibiting a high contrast ratio and excellent image sharpness while preventing sparkling defects.

In this specification, the light-transmitting substrate; And a hard coating layer comprising a binder resin, organic fine particles dispersed in the binder resin, and a siloxane polymer, wherein the ratio of two or more organic fine particles that aggregate with each other among the entire organic fine particles is 90% to 96%, for a display device An optical laminate can be provided.

Further, in the present specification, a display device including the optical laminate for the display device is provided.

Hereinafter, an optical laminate for a display device and a display device including the same according to a specific embodiment of the present invention will be described in more detail.

In the present specification, (meth) acrylate [(Meth) acrylate] is meant to include both acrylate and methacrylate.

In addition, the photocurable resin collectively refers to a polymer resin polymerized by irradiation with light, for example, by irradiation with visible light or ultraviolet light.

In the present specification, the weight average molecular weight refers to the weight average molecular weight in terms of polystyrene measured by the GPC method. In the process of measuring the weight average molecular weight in terms of polystyrene measured by the GPC method, a commonly known analysis device, a detector such as a Refractive Index Detector, and a column for analysis can be used, and a commonly applied temperature Conditions, solvents, and flow rates can be applied. For a specific example of the measurement conditions, using a Waters PL-GPC220 instrument using a Polymer Laboratories PLgel MIX-B 300mm length column, the evaluation temperature is 40 ℃, 1,2,4-trichlorobenzene was used as a solvent The flow rate was 1 mL/min, the sample was prepared at a concentration of 10 mg/10 mL, and then supplied in an amount of 200 μL, and the value of Mw can be calculated using a calibration curve formed using a polystyrene standard. The molecular weight of the polystyrene standard was 2,000 / 10,000 / 30,000 / 70,000 / 200,000.

According to one embodiment of the invention, a light-transmitting substrate; And a hard coating layer comprising a binder resin, organic fine particles dispersed in the binder resin, and a siloxane polymer, wherein the ratio of two or more organic fine particles that aggregate with each other among the entire organic fine particles is 90% to 96%, for a display device An optical laminate can be provided.

On the outermost surface of the display, an anti-glare coating layer is formed to reduce surface reflection and increase the visibility of an image, and surface irregularities are formed by aggregation of organic or inorganic particles included in the anti-glare coating layer to induce diffuse reflection of light. However, there is a problem in that the reflected light is amplified from a portion having a large size of agglomeration formed by the organic or inorganic particles and is recognized as a defect, which is referred to as a sparkling defect or a glare defect.

The closer the distance to the user is, the greater the decrease in visibility for sparkling defects appears, and accordingly, development of a film capable of preventing sparkling defects while exhibiting high contrast ratio and excellent image sharpness is required.

The present inventors induce a scattering effect of light through the organic fine particles included in the hard coating layer, and make the organic fine particles more evenly distributed in the hard coating layer, resulting in a high contrast ratio and excellent image sharpness, and poor sparkling. An optical laminate for display device capable of preventing

Specifically, a ratio of two or more organic fine particles that aggregate with each other among all of the organic fine particles included in the hard coating layer may be 90% to 96%. The'aggregation' includes all cases where the two or more organic fine particles are in contact or portions of the particles overlap.

Whether or not the'aggregation' is determined by judging the plane of the hard coating layer under an optical microscope to determine if two or more organic particles are in contact with each other or are agglomerated, and after confirming the number of agglomerations in this manner, the same The percentage of aggregated particles can be calculated by dividing by the total number of particles on the measurement surface.

The hard coating layer includes the siloxane polymer together with the organic fine particles, so that the siloxane polymer is mainly distributed outside or around the organic fine particles, thereby preventing excessive aggregation of the organic fine particles.

Accordingly, the rate of aggregation of two or more organic fine particles included in the hard coating layer is adjusted to 90% to 96%, or 91% to 97%, or 93% to 95%, to prevent occurrence of sparkling defects, and Merchant sharpness can be greatly improved.

More specifically, when observed in the planar direction of the hard coating layer, when the agglomeration ratio of two or more organic particles exceeds 96%, it can be seen that the organic particles are excessively aggregated, and accordingly, a sparkling phenomenon occurs or the surface Excessively large bumps may appear on the skin.

In addition, when observed in the planar direction of the hard coating layer, the agglomeration ratio of two or more organic particles is less than 90%, and the aggregation ratio of the organic particles is too low, so that the hard coating layer may be difficult to implement anti-glare properties, A rainbow phenomenon may appear largely due to interference of visible light.

As described above, the siloxane polymer is mainly distributed around the organic fine particles in the hard coating layer to prevent agglomeration of the organic fine particles.

The specific type of the siloxane polymer is not limited, but may be, for example, polysiloxane, polysilane, polycarbosilane, or the like.

The siloxane polymer may have a weight average molecular weight of 1,000 to 100,000. If the weight average molecular weight of the siloxane polymer is too small, the siloxane polymer may not be sufficiently distributed around the organic fine particles. In addition, when the weight average molecular weight of the siloxane polymer is too high, organic fine particles may be excessively aggregated or a large number of protrusions may occur in the hard coating layer.

In the hard coating layer, the siloxane polymer is mainly distributed around the organic fine particles, and the content of the siloxane polymer is not limited, but the hard coating layer contains 0.1 to 10 parts by weight of the siloxane polymer relative to 100 parts by weight of the organic fine particles. I can.

If the content of the siloxane polymer relative to the organic fine particles in the hard coating layer is too high, the agglomeration ratio of the organic fine particles may be greatly increased, a sparkling defect may occur, or the image clarity may be reduced, _ uneven particle distribution. Or, the haze level of the hard coat layer may be high. In addition, if the content of the siloxane polymer in the hard coating layer is too low relative to the organic fine particles, the anti-glare effect may not sufficiently occur, which is technically disadvantageous.

On the other hand, in general, the higher the haze value is, the greater the degree of diffusion of external light, so that the anti-glare effect is excellent, while the contrast ratio decreases due to distortion of the image due to surface scattering and whitening due to internal scattering.

On the other hand, the optical laminate for a display device according to the embodiment can exhibit a high contrast ratio and excellent image clarity while having a low haze value, and can prevent sparkling defects.

More specifically, the ratio of the internal haze to the external haze of the optical laminate for a display device may be 3 or less, or 0.5 to 2.5, or 0.8 to 2. The ratio of the internal haze to the external haze of the optical laminate for the display device is the difference in refractive index between the binder resin included in the hard coating layer and the organic particles or inorganic particles, the volume fraction of the organic particles or inorganic particles in the hard coating layer, organic It may be due to the agglomerated form and size of the particles or inorganic particles or two or more types of particles.

As the ratio of the internal haze to the external haze of the optical laminate for display device is 3 or less, or 0.5 to 2.5, or 0.8 to 2, the optical laminate for display device has excellent image sharpness and thus realizes high contrast ratio. Thus, a clear image can be realized, and the distribution of particles is uniform while having a low haze, preventing the occurrence of sparkling defects.

When the ratio of the internal haze to the external haze of the optical laminate for a display device is too low, reflection of external sunlight may be insufficient, so that the visibility of the image may be lowered and the image may not be clearly visible. In addition, when the ratio of the internal haze to the external haze of the optical laminate for a display device is too high, the scattering of light that embodies an image increases, so that the image may not be clearly visible.

Specifically, the optical laminate for a display device of the embodiment may have an external haze of 2% to 20%, or 3% to 15% in a range satisfying the ratio of the internal haze to the external haze, and 3% To 30%, or 5% to 20% of an internal haze value.

Meanwhile, the optical laminate for a display device may be provided by allowing the organic fine particles to be more uniformly dispersed and distributed when the hard coating layer is manufactured. For example, by using a predetermined mixed solvent and using a coating composition formed by mixing a monomer forming the binder resin of the hard coating layer, the siloxane polymer, and organic fine particles under a predetermined stirring condition, the hard coating layer and the display device An optical laminate for can be provided.

The specific combination of the organic solvent used to provide the hard coating layer and the optical laminate for a display device is not limited, but a ketone solvent and an acetate solvent may be mixed and used, for example, 6:1 to 1:1, Alternatively, it may be used by mixing in a weight ratio of 4:1 to 1.5:1.

The acetates may be methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, or cellosolve acetate, and the ketones may be methyl ethyl ketone, methyl isobutyl ketone (MIBK), acetylacetone, or acetone. However, it is not limited to the above-described example.

It is also possible to use additional solvents other than the acetate solvent and ketone solvent, for example, lower alcohols having 1 to 6 carbon atoms, cellosolves, dimethyl formamide, tetrahydrofuran, propylene glycol monomethyl ether, toluene, and xyrin. One or a mixture of one or more selected from the group consisting of ren may be used. At this time, the lower alcohols may be methanol, ethanol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, or diacetone alcohol.

The hard coating layer may have an appropriate thickness according to the specific use of the optical laminate for a display device, for example, 1 μm to 10 μm, or 2 μm to 8 μm. Specifically, when the optical laminate for a display device is used for the purpose of being positioned on the outermost surface of the notebook, outdoor electric signboard, or TV display device, the hard coating layer may have a thickness of 3 μm to 8 μm.

The specific type or size of the organic fine particles is not limited, but as a specific example, the organic fine particles may have a refractive index of 1.500 to 1.600 based on a wavelength of 550 nm.

Specific examples of the organic fine particles are not limited, for example, polystyrene, polymethyl methacrylate, polymethyl acrylate, polyacrylate, polyacrylate-co-styrene, polymethylacrylate-co-styrene, polymethyl Methacrylate-co-styrene, polycarbonate, polyvinyl chloride, polybutylene terephthalate, polyethylene terephthalate, polyamide, polyimide, polysulfone, polyphenylene oxide, polyacetal, epoxy resin, phenol resin, One selected from silicone resin, melamine resin, benzoguamine, polydivinylbenzene, polydivinylbenzene-co-styrene, polydivinylbenzene-co-acrylate, polydiallylphthalate and triallylisocyanulate polymer A single product or a copolymer of two or more thereof may be used.

In order to optimize the light scattering effect in the optical laminate for a display device, the organic fine particles may be particles having a particle diameter of 1 to 50 µm, preferably 1 to 30 µm. In the hard coating layer, in order to control the ratio of two or more organic fine particles that aggregate with each other to be 5% or less among the whole organic fine particles, the diameter of the organic fine particles is also preferably within a predetermined range, and specifically, the organic fine particles are 1 μm. It may have a diameter of to 10㎛.

Meanwhile, since the organic fine particles are a component added to induce light scattering effect to prevent glare, the hard coating layer is 0.1 to 40 parts by weight, or 0.5 to 40 parts by weight of the organic fine particles relative to 100 parts by weight of the binder resin. It may contain 20 parts by weight, or 1 to 10 parts by weight.

If the content of the organic fine particles in the hard coating layer is too low, the haze value due to internal scattering may not be sufficiently realized, and if the content of the organic fine particles in the hard coating layer is too high, the viscosity of the coating composition forming the hard coating layer As a result, the coating property becomes poor, and the haze value due to internal scattering becomes too large, and the contrast ratio may decrease.

In particular, the hard coating layer may contain 0.1 to 40 parts by weight, or 0.5 to 20 parts by weight, or 1 to 10 parts by weight of the organic fine particles relative to 100 parts by weight of the binder resin. If the content of the organic fine particles is too low, the internal Since the haze value due to scattering is not sufficiently implemented, image condensation of the reflected image may increase, and if the content of the organic fine particles is too high, the haze value may be too high, resulting in a decrease in image clarity or a contrast ratio.

Meanwhile, the hard coating layer may include a separate filler other than the organic fine particles. Examples of the additional filler that may be included are not limited to a large extent, and may be, for example, inorganic fine particles composed of silicon oxide, titanium dioxide, indium oxide, tin oxide, zirconium oxide, and zinc oxide. The inorganic fine particles may be particles having a diameter of 0.001 μm to 5 μm. However, the fine particles included in the hard coating layer of the optical laminate for the display device are mainly organic fine particles, and even if the inorganic fine particles are included, the content may be relatively small. For example, the inorganic fine particles in the hard coating layer The content of the fine particles may be 10% by weight or less, 5% by weight or less, 1% by weight or less, 0.1% by weight or less, 0.01% by weight or less, or 0.001% by weight or less based on 100 parts by weight of the binder resin.

Meanwhile, the binder resin may include a polymer or copolymer of a vinyl-based monomer or a (meth)acrylate-based monomer.

The vinyl-based monomer or (meth)acrylate-based monomer may include a (meth)acrylate or a monomer or oligomer containing one or more, two or more, or three or more of a vinyl group.

Specific examples of the monomer or oligomer including the (meth)acrylate include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate. )Acrylate, tripentaerythritol hepta(meth)acrylate, triethylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxy tri(meth)acrylic Rate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, butanediol dimethacrylate, hexaethyl methacrylate, butyl methacrylate, or a mixture of two or more thereof, or urethane-modified acrylate oligomer, epoxide Side acrylate oligomers, ether acrylate oligomers, dendritic acrylate oligomers, or mixtures of two or more thereof. At this time, the molecular weight of the oligomer is preferably 1,000 to 10,000.

Specific examples of the monomer or oligomer containing the vinyl group may include divinylbenzene, styrene, or paramethylstyrene.

In addition, the polymer or copolymer contained in the binder resin may include a reactive acrylate oligomer group consisting of a urethane acrylate oligomer, an epoxy acrylate oligomer, a polyester acrylate, and a polyether acrylate; And dipentaerythritol hexaacrylate, dipentaerythritol hydroxy pentaacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, trimethylene propyl triacrylate, propoxylated glycerol triacrylate, trimethylpropane ethoxy tri At least one selected from the group of polyfunctional acrylate monomers consisting of acrylate, 1,6-hexanediol diacrylate, propoxylated glycero triacrylate, tripropylene glycol diacrylate, and ethylene glycol diacrylate It may further include a moiety derived from a monomer.

On the other hand, in the step of forming the hard coating layer, a method and apparatus commonly used to apply a photopolymerizable coating composition may be used without any other limitation. For example, a bar coating method such as Meyer bar, a gravure coating method, 2 roll reverse coating method, vacuum slot die coating method, and 2 roll coating method can be used.

In the step of forming the hard coating layer, ultraviolet or visible light having a wavelength of 200 to 400 nm may be irradiated, and the exposure amount at the time of irradiation is preferably 100 to 4,000 mJ/cm 2. The exposure time is also not particularly limited, and can be appropriately changed according to the exposure apparatus used, the wavelength of the irradiated light, or the amount of exposure. In addition, in the step of forming the hard coating layer, nitrogen purging may be performed to apply a nitrogen atmosphere.

Meanwhile, the light-transmitting substrate may be a transparent film having a light transmittance of 90% or more and a haze of 1% or less. In addition, the material of the substrate may be triacetyl cellulose, a cycloolefin polymer, poly(meth)acrylate, polycarbonate, polyethylene terephthalate, or the like. In addition, the thickness of the base film may be 10 to 300 μm in consideration of productivity, but is not limited thereto.

More specifically, the retardation (Rth) in the thickness direction measured at a wavelength of 400 nm to 800 nm of the light-transmitting substrate may be 3,000 nm or more, or 5,000 nm or more, or 5,000 nm to 20,000 nm.

Specific examples of such a light-transmitting substrate include a uniaxially oriented polyethylene terephthalate film or a biaxially oriented polyethylene terephthalate film.

When the optical laminate for a display device includes a light-transmitting substrate having a retardation (Rth) of 3,000 nm or more, or 5,000 nm or more, or 5,000 nm to 20,000 nm in the thickness direction measured at the wavelength of 400 nm to 800 nm, Compared to the case of using a retardation of 1000 to 3000 nm or less, a rainbow phenomenon due to interference of visible light may be alleviated.

The retardation (Rth) in the thickness direction can be confirmed through a commonly known measuring method and measuring device. For example, as an apparatus for measuring retardation Rth in the thickness direction, the brand name "AxoScan" manufactured by AXOMETRICS, etc. is mentioned.

For example, as a measurement condition for retardation (Rth) in the thickness direction, after inputting a refractive index (589 nm) value into the measuring device for the light-transmitting base film, temperature: 25°C, humidity: 40% Under conditions, using light with a wavelength of 590 nm, the retardation in the thickness direction of the light-transmitting base film is measured, and the obtained thickness direction retardation measurement value (measured value by automatic measurement (automatic calculation) of the measuring device) Then, it can be calculated|required by converting it to the retardation value per 10 micrometers of thickness of a film. In addition, the size of the light-transmitting substrate of the measurement sample is not particularly limited, since it may be larger than the light metering portion (diameter: about 1 cm) of the stage of the measuring device, but it can be made into a size of 76 mm in length, 52 mm in width and 13 μm in thickness. .

In addition, the value of the ``refractive index of the light-transmitting substrate (589 nm)'' used for the measurement of retardation (Rth) in the thickness direction is the same type of resin film as the light-transmitting substrate that forms a film to be measured for retardation. After forming the unstretched film to be included, such an unstretched film is used as a measurement sample (in addition, when the film to be measured is an unstretched film, the film can be used as it is as a measurement sample), and a measuring device As a refractive index measuring device (trade name "NAR-1T SOLID" manufactured by Atago Co., Ltd.) is used, a light source of 589 nm is used, and the in-plane direction of the measurement sample (vertical to the thickness direction) is used under a temperature condition of 23°C. Direction) can be obtained by measuring the refractive index for light of 589 nm.

According to another embodiment of the present invention, a display device including the optical laminate for a display device described above may be provided.

The specific example of the display device is not limited, and may be, for example, a device such as a liquid crystal display device, a plasma display device, or an organic light emitting diode device.

In the display device, the optical laminate for the display device may be provided on the outermost surface of the display panel on the viewer side or the backlight side.

More specifically, the display device may be a notebook display device, a TV display device, and an advertisement large-area display device, and the optical laminate for the display device is the notebook display device, TV display device, advertisement large-area display device. It can be located on the outermost side of the device.

According to the present invention, an optical laminate for a display device capable of preventing sparkling defects while exhibiting a high contrast ratio and excellent image sharpness, and an optical laminate for the display device, and exhibiting a high contrast ratio and excellent image sharpness A display device in which sparkling defects are prevented may be provided.

1 is a plan view of one surface of a hard coating layer obtained in Example 1 taken with an optical microscope.
2 is a plan view of one surface of a hard coating layer obtained in Comparative Example 2 taken with an optical microscope.
3 is a plan view of one surface of a hard coating layer obtained in Comparative Example 3 taken with an optical microscope.

The invention will be described in more detail in the following examples. However, the following examples are merely illustrative of the present invention, and the contents of the present invention are not limited by the following examples.

<Examples and Comparative Examples: Preparation of optical laminates for display devices>

(1) Preparation of a composition for forming a hard coating layer

A first coating solution was prepared by uniformly mixing the binder resin-forming monomer and solvent described in Table 1 below, and a second coating solution was prepared by mixing the siloxane polymer and organic fine particles in a particle dilution solvent. After sufficiently agitating each coating solution to be uniformly mixed, the two coating solutions were mixed to prepare a hard coating composition.

(2) Preparation of optical laminate for display device

The hard coating composition thus obtained was coated with #12 mayer bar on the substrate in Table 1 and dried at 60°C for 2 minutes. The dried product was irradiated with ultraviolet rays of 220 mJ/cm 2 to form a hard coating layer, and an optical laminate for a display device was manufactured.

(Content:g) Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 bookbinder PETA 25 25 25 25 25 Initiator I184 0.8 0.8 0.8 0.8 0.8 D1173 0.8 0.8 0.8 0.8 0.8 additive T270 0.06 0.06 0.06 0.06 0.06 T410 0.01 0.01 0.01 0.01 0.01 F477 0.06 0.06 0.06 0.06 0.06 menstruum MIBK 30 30 30 30 30 2-BuOH 20 20 20 20 20 PGMEA 10 10 10 10 10 Particle dilution solvent 2-BuOH 10 10 10 10 10 Siloxane polymer Colcoat N103-X (2% in n-BuOH, IPA) 4 2 0.5 8 Inorganic fine particles MA-ST (30% in MeOH) 0.4 Organic fine particles 2 um 1.555 1.5 1.5 1.5 1.5 1.5 PS/PMMA bead 113BQ materials SRF PET (>5000)

* PETA: Pentaerythritol triacrylate, SK Entis product

MA-ST: A dispersion solution in which spherical silica particles with a volume average particle diameter of 12 nm and a refractive index of 1.43 (manufactured by Nissan Chemical) are dispersed in methanol at a concentration of 30%

MIBK: methyl isobutyl ketone

2-BuOH: 2-butanol

PGMEA: Propylene glycol methyl ether acetate

n-BA: normal butyl acetate

EB-1290: Photo-curing Aliphatic Urethane Hexaacrylate / SK Entis / 100% solid content

I184: photo-curing initiator (Irgacure 184, manufactured by BASF)

T270: Leveling additive with 100% solid content (Tego-Glide 270, manufactured by Tego Evonik)

F477: 100% solid content, Florin leveling additive (F477, manufactured by DIC Chemical)

113BQ (XX-113BQ, manufactured by Sekisui Plastic): Polystyrene-Polymethylmethacrylate crosslinked copolymer fine particles with a refractive index of 1.555 and an average particle diameter of 2㎛

*SRF PET: Super Retarder Film PolyEthylene Terephthalate

[Experimental Example]

1. Check the percentage of organic fine particles agglomerated in the hard coating layer

For the hard coating layer obtained in each of the above Examples and Comparative Examples, a transmission image was taken with an optical microscope (Olympus BX51 optical microscope), and the ratio of the organic fine particles aggregated with each other was confirmed. Specifically, the film was placed so that the hard coating layer was facing the objective lens, and the transmitted image was observed by setting the alternative lens 10 times, the objective lens 20 times or 50 times.

It was determined that the case where two or more organic fine particles were in contact with each other or lumped together based on the plane of the hard coating layer was in a cured state. After checking the number of aggregated particles in this way, the ratio of the aggregated particles was calculated by dividing by the number of total particles on the same measurement surface.

2. Transmittance and overall/internal/external haze evaluation

A specimen of 4 cm x 4 cm was prepared from the optical laminate for a display device obtained in each of the above Examples and Comparative Examples and measured three times with a haze meter (HM-150, A light source, Murakami Corporation) to calculate an average value, and the total haze. It was calculated as a value. At the time of measurement, transmittance and haze were measured simultaneously, and transmittance was measured according to JIS K 7105 standard, and haze was measured according to JIS K 7105 standard. In the measurement of internal haze, an adhesive film having a total haze of 0 was applied to the coated surface of the optical film to be measured to make the surface unevenness flat, and then the internal haze was measured in the same manner as the above total haze.

The external haze was calculated as the average value of the calculated value difference between the total haze and the measured value of the internal haze.

3. Check the occurrence of rainbow

A specimen of 10 cm x 10 cm was prepared from the optical laminate for a display device obtained in each of the above Examples and Comparative Examples, and a black film (UTS-30BAF film, Nitto) was attached to the opposite side of the hard coating layer using a lamination process. After reflecting the light of the three-wavelength lamp on the hard coating surface of the film, it was confirmed whether the reflected image had a rainbow.

<Measurement criteria>

X: Rainbow is not recognized

Middle: Rainbow is weakly recognized. Average wavelength difference between colors that form rainbow such as green-blue, blue-purple is 80nm or less

Strong: The colors that form the rainbow, such as red-green, orange-blue, etc., are strongly recognized, or the average wavelength difference is more than 100 nm.

5. Checking sparkling occurrence

For the optical laminate for a display device obtained in each of the above Examples and Comparative Examples, a sample was prepared in a size of 12 cm x 12 cm, and then the sample was placed on a 150 PPI panel with the hard coating side facing up. At this time, tape may be applied to the slopes so that the film does not lift. Then, after driving the panel so that the white screen was visible, it was checked whether sparkling occurred in an area within 10 cm x 10 cm of the sample.

<Measurement criteria>

Good: No sparkling

Bad: Sparkling occurs

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Hard coating layer thickness 4 μm 4 μm 4 μm 4 μm 4 μm Transmittance 93.0 92.6 93.0 93.1 92.8 Internal haze(hi) 2.4 2.4 2.4 2.5 2.3 External haze(Hs) 1.8 2.2 2.4 0.6 5.2 hi/Hs 1.3 1.1 One 4.2 0.4 Rainbow X X X Y X sparkling Good Good Bad Good Bad Particle aggregation rate 95 95 98 85 98.5

As can be seen in Table 2, the ratio of the aggregated organic fine particles in the total organic fine particles is 90% to 96%, and the ratio of the internal haze to the external haze is 2.5 or less, the optical laminate for a display device of Examples 1 to 2 It was confirmed that the rainbow phenomenon and sparkling phenomenon do not occur, and excellent image sharpness can be realized.

On the other hand, it was confirmed that the optical laminates for display devices of Comparative Examples 1 and 3, in which the proportion of the organic fine particles aggregated among the total organic fine particles was 98% or more, had excessive sparkling and low image sharpness.

In addition, it was confirmed that the optical laminate for a display device of Comparative Example 2 in which the ratio of the aggregated organic particles was 85% and the ratio of the internal haze to the external haze was 4.2, which generated rainbow and showed low image clarity. Became.

Claims (13)

Light-transmitting substrate; And
Including; a binder resin, a hard coating layer including organic fine particles and siloxane polymer dispersed in the binder resin,
The ratio of two or more organic fine particles that aggregate with each other among the whole organic fine particles is 90% to 96%,
Optical laminate for display devices.
The method of claim 1,
The optical laminate for a display device, wherein the ratio of the internal haze to the external haze of the optical laminate for a display device is 3 or less.
The method of claim 1,
The siloxane polymer has a weight average molecular weight of 1,000 to 100,000, optical laminate for a display device.
The method of claim 1,
The hard coating layer comprises 0.1 to 10 parts by weight of the siloxane polymer relative to 100 parts by weight of the organic fine particles, an optical laminate for a display device.
The method of claim 1,
It is determined that the two organic fine particles of the two or more organic fine particles are in contact with each other or portions of the particles overlap each other.
The method of claim 1,
The hard coating layer has a thickness of 1 μm to 10 μm, an optical laminate for a display device.
The method of claim 1,
The organic fine particles have a diameter of 0.5 µm to 6 µm, and have a refractive index of 1.500 to 1.600 based on a wavelength of 550 nm.
The method of claim 1,
The binder resin comprises a polymer or copolymer of a vinyl-based monomer or a (meth)acrylate-based monomer, an optical laminate for a display device.
The method of claim 1,
The hard coating layer comprises 0.5 to 20 parts by weight of the organic fine particles relative to 100 parts by weight of the binder resin, the optical laminate for a display device.
The method of claim 1,
The light-transmitting substrate includes a light-transmitting substrate having a retardation (Rth) of 3,000 nm or more in a thickness direction measured at a wavelength of 400 nm to 800 nm.
The method of claim 1,
Further comprising a low refractive index layer formed on the hard coating layer to face the light-transmitting substrate, the optical laminate for a display device.
A display device comprising the optical laminate of claim 1.
The method of claim 12,
The display device is a display device for a notebook,
The optical laminate for the display device is located on the outermost surface of the display device for the notebook, display device.

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