JP2024515592A - Polarizing laminate and image display device including same - Google Patents

Abstract

The polarizing laminate includes the polarizer of the present invention, a surface treatment layer formed on one surface of the polarizer and having a haze value of 15% to 40% and a reflectance of 2.5% or less, a phase retardation layer formed on the other surface of the polarizer, and a pressure-sensitive adhesive layer formed on the surface of the phase retardation layer. It is possible to prevent the seams of the image display device from being visible, and to improve the optical characteristics of the image display device. [Selected Figure] Figure 2

Description

The present invention relates to a polarizing laminate and an image display device including the same. More specifically, the present invention relates to a polarizing laminate including a polarizer and a functional film, and an image display device including the same.

In recent years, various image display devices such as liquid crystal displays (LCDs), electroluminescent (EL) displays, plasma display panels (PDPs), field emission displays (FEDs), etc. have become commercially available and are in use. As the use of image display devices has become more common, active research has been conducted to improve the functions of image display devices. For example, research is being conducted on polarizing laminates for use in image display devices.

In general, a polarizing laminate includes an iodine-based polyvinyl alcohol (PVA) polarizer and a protective film for protecting one or both sides of the polarizer. As an example of the structure of the polarizing laminate, a protective film may be laminated on one side of the polarizer, and a protective film, an adhesive layer, a release film, etc. may be laminated in that order on the other side.

In addition to the polarizing laminate, the image display device may also include a surface treatment layer to improve display quality. The surface treatment layer may also further include an antiglare layer, a low reflection layer, or a hard coat film, etc.

Increasing the thickness of the surface treatment layer to improve hardness may cause the surface treatment layer to peel off from the substrate. Also, physical properties such as scratch resistance or impact resistance may be insufficient. Furthermore, conventional surface treatment layers do not provide sufficient optical properties, so further research is needed to realize large-area image display devices.

For example, Korean Patent Publication No. 10-2013-0074167 discloses a plastic substrate including a hard coat layer. However, the optical properties are insufficient and the above-mentioned problems are not addressed.

The objective of the present invention is to provide a polarizing laminate with improved optical properties.

The objective of the present invention is to provide an image display device with improved optical properties.

1. A polarizing laminate comprising a polarizer, a surface treatment layer formed on one surface of the polarizer and having a haze value of 15% to 40% and a reflectance of 2.5% or less, a phase retardation layer formed on the other surface of the polarizer, and a pressure-sensitive adhesive layer formed on the surface of the phase retardation layer.

2. The polarizing laminate according to item 1, further comprising a protective film laminated on the surface of the surface treatment layer.

3. The polarizing laminate according to item 1, wherein the surface treatment layer includes a hard coat film.

4. The polarizing laminate according to item 3, wherein the surface treatment layer is formed from a coating composition containing a (meth)acrylate compound.

5. The polarizing laminate according to item 3, wherein the surface treatment layer further contains an ion-conductive material.

6. The polarizing laminate according to item 1, wherein the thickness of the surface treatment layer is 1 to 20 μm.

7. An image display device including a substrate, the polarizing laminate described in item 1 laminated on the substrate, and a display panel disposed below the substrate.

8. In the image display device according to item 7, the polarizing laminate is laminated such that the adhesive layer, the phase retardation layer, the polarizer, and the surface treatment layer are arranged in this order from the substrate.

9. The image display device according to item 7, wherein the display panel includes a micro light-emitting diode (LED) module.

10. In the image display device according to item 9, the micro LED module includes an array in which a plurality of micro LED chips are combined.

According to an embodiment of the present invention, it is possible to provide a polarizing laminate in which a surface treatment layer having a predetermined haze value is laminated with a polarizer, a phase retardation layer, and a pressure-sensitive adhesive layer. In addition, by using a surface treatment layer having a predetermined haze value, it is possible to improve the optical characteristics of an image display device.

When the surface treatment layer according to the exemplary embodiment is included, the seams in the display panel are not visible, brightness is improved, and vivid colors can be achieved.

In addition, by including a surface treatment layer in the polarizing laminate, it is possible to suppress the occurrence of color differences due to seams. This makes it possible to easily expand the area of the display panel, thereby reducing the process costs required to increase the area of image display devices.

FIG. 1 is a schematic cross-sectional view illustrating a polarizing laminate according to an exemplary embodiment. FIG. 2 is a schematic cross-sectional view illustrating a polarizing laminate according to an exemplary embodiment. FIG. 3 is a schematic cross-sectional view of an image display device including a polarizing laminate according to an exemplary embodiment.

Mode for carrying out the invention

An embodiment of the present invention discloses a polarizing laminate that includes a polarizer, a surface treatment layer formed on one surface of the polarizer and having a haze value of 15% to 40% and a reflectance of 2.5% or less, a phase retardation layer formed on the other surface of the polarizer, and an adhesive layer formed on the surface of the phase retardation layer.

By using the polarizing laminate, it is possible to reduce the visibility of seams located on the display panel of an image display device, and to reduce the occurrence of color differences due to the seams. In addition, the polarizing laminate can improve the clarity of the image display device. Each component will be described in detail below.

In this specification, the term "dispose" is used as a term that encompasses "form," "position," "laminate," or "apply." Furthermore, "dispose" is a term used to describe the relative positions of each layer included in the illustrative examples and comparative examples, and does not limit the manufacturing method of each layer. Furthermore, even if "laminate" is used instead of "dispose," the above description does not necessarily mean that a specific layer must be in contact with one side of another layer in a "laminate" manner.

In addition, in this specification, "one side" and "the other side" are used as relative concepts. For example, if "one side" is the top side, the bottom side can be referred to as "the other side". Conversely, if "one side" is the bottom side, the top side can be referred to as "the other side".

In addition, in this specification, the terms "top," "upper surface," "upper part," "viewing side," "lower," "lower surface," "lower part," "panel side," and the like are based on the orientation of the drawing. For example, if one surface of a particular layer is disposed toward the top of the drawing, the one surface can be referred to as the "viewing side," "upper surface," or "upper part." Furthermore, the surface opposite the one surface, i.e., the other surface, can be referred to as the "panel side," "lower surface," or "lower part."

In addition, "top", "upper surface" or "upper part" can be used to refer to the position from which the observer is looking (i.e., the viewing side). Therefore, the observer can generally be understood as being positioned in the upper surface direction and looking in the lower surface direction. "Bottom", "lower surface" or "lower part", as concepts contrasted with the observer's position, can be used to refer to the position of the display panel (i.e., the panel side).

<Surface treatment layer>
The haze value of the surface treatment layer according to the exemplary embodiment may be 15% to 40%. The haze value is the degree of cloudiness that appears when light passes through a sample, and means a ratio of diffuse transmission (Td) divided by total transmission (Tt). The diffuse transmission (Td) refers to the amount of scattered light among the light that passes through the sample, and the total transmission (Tt) refers to the amount of all light that passes through the sample. Meanwhile, the parallel transmission (Tp) refers to the amount of light that passes through the transmitted light without scattering, and may be a value obtained by subtracting the diffuse transmission (Td) from the total transmission (Tt).

In addition, by having the surface treatment layer satisfy the above-mentioned haze value, the phenomenon in which the seams between display panels are visible can be suppressed. If the haze value of the surface treatment layer is less than 15%, the seams between display panels may be visible. If the haze value of the surface treatment layer exceeds 40%, there is a risk that the optical characteristics of the image display device, such as clarity, will deteriorate due to excessive diffusion of light.

Preferably, the reflectance of the surface treatment layer may be 2.5% or less. The reflectance of the surface treatment layer may mean the surface reflectance. By reducing the surface reflectance, the clarity and color reproducibility of the image display device can be improved.

In an exemplary embodiment, the surface treatment layer may include a polymer resin with guaranteed transparency. Examples of the polymer resin included in the surface treatment layer include at least one polymer resin selected from the group consisting of cycloolefin derivatives having a monomer unit including a cycloolefin such as norbornene or a polycyclic norbornene monomer, cellulose (diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, isobutyl ester cellulose, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose), ethylene vinyl acetate copolymer, polyester, polystyrene, polyamide, polyetherimide, polyacrylic, polyimide, polyethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyethersulfone, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyurethane, and polyepoxy.

The surface treatment layer may be an unstretched film or may include a uniaxially or biaxially stretched film. In some exemplary embodiments, a uniaxially or biaxially stretched polyester film, a cycloolefin derivative film, or a triacetyl cellulose film may be used as the surface treatment layer to improve transparency, heat resistance, or optical properties.

Furthermore, the surface treatment layer may be a hard coat film, an antistatic hard coat film, an antiglare coat layer, an antistatic antiglare coat layer, or a low reflection coat layer. Alternatively, the surface treatment layer may be a composite layer including a hard coat film, an antistatic hard coat film, an antiglare coat layer, an antistatic antiglare coat layer, or a low reflection coat layer.

In some exemplary embodiments, the hard coat film can be obtained from an ultraviolet curable resin composition. The ultraviolet curable resin composition can include a multifunctional (meth)acrylate, a photopolymerization initiator, and an organic solvent. The (meth)acrylate includes both acrylates and methacrylates.

In addition, in some exemplary embodiments, examples of polyfunctional (meth)acrylates include dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, (meth)acrylic acid ester, trimethylolpropane tri(meth)acrylate, glycerol tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, ethylene glycol di(meth)acrylate, propylene glycol (meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, bis(2-hydroxyethyl)isocyanurate di(meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, isooctyl (meth)acrylate, isodexyl (meth)acrylate, stearyl (meth)acrylate, tetrafurfuryl (meth)acrylate, and phenoxyethyl (meth)acrylate.

In some exemplary embodiments, examples of photopolymerization initiators include diphenyl ketone benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylamine benzoate, 2-hydroxy-2-methyl-1-phenyl-1-one, 4-hydroxycyclophenyl ketone, dimethoxy-2-phenylacetophenone, anthraquinone, 2-aminoanthraquinone, fluorene, triphenylamine, carbazole, benzophenone, p-phenylbenzophenone, 3-methylacetophenone, 4,4-dimethoxyacetophenone, 4,4-diaminobenzophenone, benzoin, and 2-ethylthioxanthone.

The organic solvent is also compatible with the polyfunctional (meth)acrylate. Examples of organic solvents include methanol, ethanol, isopropanol, propanol, butanol, isobutanol, ethyl cellosolve, methyl cellosolve, butyl acetate, dimethylformamide, diacetone alcohol, ethylene glycol isopropyl alcohol, propylene glycol isopropyl alcohol, methyl ethyl ketone, and N-methylpyrrolidone.

In some exemplary embodiments, additives can be used to further improve the mechanical properties of the surface treatment layer. For example, nanosilica particles can be used to improve the surface strength of the surface treatment layer, and photopolymerization initiators can be used to improve the photopolymerization efficiency. In addition, fillers, leveling agents, defoamers, UV absorbers, antioxidants, etc. can be added.

In some exemplary embodiments, the hard coat film may be an anti-glare coating layer that has been given anti-glare properties. In order to give the hard coat film anti-glare properties, inorganic particles such as silica or polymer particles such as polymethyl methacrylate (PMMA) may be used. In order to improve dispersibility, the polymer particles may be monodisperse particles, polydisperse particles, or a mixture of the monodisperse and polydisperse particles with an average particle size of 1 to 20 μm.

In some exemplary embodiments, a conductive substance can be further used to impart antistatic properties to the hard coat film or antiglare coat layer. The conductive substance is contained in the coating liquid composition and can impart antistatic properties to the coating layer. Examples of conductive substances include cationic surfactants such as quaternary ammonium salts, phosphonium salts, and sulfonium salts; anionic surfactants such as carboxylic acids, sulfonates, sulfates, phosphates, and phosphites; cationic surfactants such as sulfobetaines, alkyl betaines, and alkyl imidazolium betaines; and nonionic surfactants such as polyhydric alcohol derivatives, sorbitan fatty acid monoesters and diesters, and polyalkylene oxide derivatives.

Other examples of conductive materials include permanent antistatic agents made by mixing hydrophilic polymers such as polyethylene methacrylate with acrylic resins, conductive fillers such as acetylene black or aluminum oxide, and conductive polymers such as polypyrrole, polythiophene, and polyaniline.

In an exemplary embodiment, a polarizer can be laminated on one side of the surface treatment layer. In some exemplary embodiments, a protective film can be laminated on the other side of the surface treatment layer. Thus, in some exemplary embodiments, the protective film, the surface treatment layer, and the polarizer can be laminated in sequence.

In an exemplary embodiment, the thickness of the surface treatment layer may be 0.1 to 200 μm, preferably 1 to 50 μm, and more preferably 1 to 20 μm. Within the above numerical range, the mechanical strength of the surface treatment layer can be improved, and it is easy to increase the area of the surface treatment layer. For example, if the thickness of the surface treatment layer is less than 0.1 μm, the mechanical strength of the surface treatment layer may be insufficient, and if the thickness of the surface treatment layer exceeds 20 μm, excessive process costs may be required to increase the area of the surface treatment layer.

<Polarizer>
The polarizer may be a stretchable film having a dichroic dye adsorbed and oriented therein. The stretchable film may contain a resin that can be dyed with a dichroic substance. For example, the stretchable film may contain a hydrophilic polymer such as a polyethylene terephthalate resin, an ethylene-vinyl acetate copolymer, an ethylene-vinyl alcohol copolymer, a cellulose resin, a polyvinyl alcohol-based resin, or a partially saponified resin thereof; or a polyene-oriented resin such as a dehydrated polyvinyl alcohol-based resin or a dehydrochlorinated polyvinyl alcohol-based resin.

Preferably, polyvinyl alcohol resins can be used because they ensure uniformity of the degree of polarization within the plane and have excellent dyeing affinity for dichroic materials.

For example, the polarizer may contain a polyvinyl alcohol resin obtained by saponifying a polyvinyl acetate resin. Examples of polyvinyl acetate resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and monomers copolymerizable therewith. Examples of monomers copolymerizable with vinyl acetate include unsaturated carboxylic acid monomers, unsaturated sulfonic acid monomers, olefin monomers, vinyl ether monomers, and acrylamide monomers having an ammonium group.

The polyvinyl alcohol resin may be modified. For example, polyvinyl formal or polyvinyl acetal modified by the addition of an aldehyde compound may be used.

Polarizers can be obtained by processing polyvinyl alcohol resin through a process that includes steps such as swelling, dyeing, crosslinking, stretching, washing with water, and drying. Polarizer manufacturing methods are classified by the stretching method. For example, stretching methods include a dry stretching method, a wet stretching method, and a hybrid stretching method that combines the above two types of stretching methods.

Below, a method for manufacturing a polarizer will be described on the assumption that a polyvinyl alcohol resin is processed using a wet stretching method, but the examples are not limited to this manufacturing method.

The swelling step, dyeing step, crosslinking step, stretching step, water washing step, and other steps can be performed while the film containing the polyvinyl alcohol resin is immersed in a thermostatic water bath. The order and number of repetitions of each step are not particularly limited, and each step may be performed simultaneously or sequentially, and some steps may be omitted as necessary.

The swelling step may be a step for removing impurities such as dust and antiblocking agents deposited on the surface of the film, and for improving the stretching efficiency and dyeing uniformity of the film. The dyeing step may be a step for adsorbing a dichroic substance to the film. To improve the dyeing efficiency, iodides may be used as dyeing assistants. Examples of iodides include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, titanium iodide, etc.

The crosslinking step can be carried out to chemically fix the dichroic material adsorbed on the film. For example, the crosslinking reaction of the dichroic material can be induced by immersing the film on which the dichroic material is physically adsorbed in an aqueous crosslinking solution containing an acetate metal salt. The drying step can be a step for drying the film that has been washed with water to further improve the orientation of the dichroic material and thereby improve the optical properties of the polarizer.

In an exemplary embodiment, the polarizer can be laminated on one side of the surface treatment layer. Also, a phase retardation layer can be laminated on the other side of the polarizer. Thus, in an exemplary embodiment, the surface treatment layer, the polarizer, and the phase retardation layer can be laminated in sequence.

<Phase Retardation Layer>
In an exemplary embodiment, the phase retardation layer may be a λ/4 phase retardation film (quarter-wave retardation film). The λ/4 phase retardation film can be obtained by uniaxially, biaxially, or other suitable orientation of a polymer film. The λ/4 phase retardation film can suppress reflected light.

Examples of polymer compounds contained in the phase retardation layer include polycarbonate compounds, polyester compounds, polysulfone compounds, polyethersulfone compounds, polystyrene compounds, polyolefin compounds, polyvinyl alcohol compounds, cellulose acetate compounds, polymethyl methacrylate compounds, polyvinyl chloride compounds, polyacrylate polyvinyl chloride compounds, polyamide polyvinyl chloride compounds, etc. Transparency can be used as an indicator for selecting polymer compounds.

Also, in an exemplary embodiment, the phase retardation layer can include a nematic or smectic liquid crystal material that can be polymerized by polymerization of the same reaction system, and preferably includes a nematic liquid crystal material. Furthermore, in an exemplary embodiment, the phase retardation layer can provide reverse wavelength dispersion and can have various retardation values.

Furthermore, in some exemplary embodiments, the phase retardation layer may further include a positive C plate layer. In addition, in order to set the thickness direction retardation (Rth) value of the polarizing laminate in an appropriate range, the retardation value of the positive C plate layer may be adjusted to a predetermined range. In some exemplary embodiments, when the thickness direction retardation value of the λ/4 retardation film is 40 nm to 65 nm, the thickness direction retardation value of the positive C plate layer may be -85 nm to -60 nm. When the thickness direction retardation value of the λ/4 retardation film is 65 nm to 80 nm, the thickness direction retardation value of the positive C plate layer may be -100 nm to -85 nm. When the thickness direction retardation value of the λ/4 retardation film is 80 nm to 100 nm, the thickness direction retardation value of the positive C plate layer may be -120 nm to -100 nm. When the thickness direction retardation value of the λ/4 retardation film is 100 nm to 180 nm, the thickness direction retardation value of the positive C plate layer may be -200 nm to -120 nm.

In an exemplary embodiment, a polarizer can be laminated on one side of the phase retardation layer, and an adhesive layer can be disposed on the other side of the phase retardation layer. For example, the polarizer, phase retardation layer, and adhesive layer can be disposed in that order. In addition, the polarizer, phase retardation layer, and adhesive layer can be oriented so that the side of the polarizer on which the phase retardation layer is not laminated faces outward.

<Adhesive Layer>
In an exemplary embodiment, the adhesive layer may be formed using a pressure sensitive adhesive (PSA) or an optically clear adhesive (OPC).

For example, a pressure-sensitive adhesive or an optically clear adhesive can be obtained from an adhesive composition comprising an acrylic copolymer and a crosslinker, or from an adhesive composition comprising a urethane (meth)acrylate resin, a (meth)acrylate ester monomer and a photoinitiator.

In exemplary embodiments, the adhesive layer can be disposed on one side of the phase retardation layer. In some exemplary embodiments, a release layer can be laminated on the other side of the adhesive layer. For example, the phase retardation layer, the adhesive layer, and the release layer can be laminated in sequence.

<Protective film>
In some exemplary embodiments, the protective film can be laminated on one side of the surface treatment layer. When the protective film is disposed on one side of the surface treatment layer, a polarizer is disposed on the other side of the surface treatment layer. For example, the protective film, the surface treatment layer, and the polarizer can be disposed in this order. In addition, the protective film can be oriented so that the one side of the protective film on which the surface treatment layer is not laminated faces the outer surface of the image display device.

In some exemplary embodiments, the resin contained in the protective film can be selected based on the transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, etc. of the protective film.

Examples of resins contained in the protective film include polyester-based resins such as polyethylene terephthalate, polyethylene isophthalate, and polybutylene terephthalate; cellulose-based resins such as diacetyl cellulose and triacetyl cellulose; polycarbonate-based resins, acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; styrene-based resins such as polystyrene and acrylonitrile-styrene copolymers; polyolefin-based resins such as polyethylene, polypropylene, polyolefins having a cyclo- or norbornene structure, and ethylene propylene copolymers; vinyl chloride-based resins; polyamide-based resins such as nylon and aromatic polyamide; imide-based resins; polyethersulfone-based resins; sulfone-based resins; polyether ketone-based resins; polyphenylene sulfide-based resins; vinyl alcohol-based resins; vinylidene chloride-based resins; vinyl butyral-based resins; arylate-based resins; polyoxymethylene-based resins; and thermoplastic resins such as epoxy-based resins.

Furthermore, a film made of a thermosetting resin or an ultraviolet-curable resin such as a (meth)acrylic, urethane, epoxy, or silicone resin may be used as the protective film. In some exemplary embodiments, a cellulose-based film having a saponified surface may be used as the protective film because it is easy to improve the polarization properties and durability.

<Release Layer>
In some exemplary embodiments, the release layer can be laminated on one side of the adhesive layer. When a release layer is disposed on one side of the adhesive layer, a phase retardation layer is disposed on the other side of the adhesive layer. For example, a phase retardation layer, an adhesive layer, and a release layer can be disposed in sequence.

In some exemplary embodiments, the release layer may be formed from a resin typically used in polarizing laminates. For example, the release layer may be formed from a polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, or polybutylene naphthalate; a polyimide resin; an acrylic resin; a styrene-based resin such as polystyrene and acrylonitrile-styrene; a polycarbonate resin; a polylactic acid resin; a polyurethane resin; a polyolefin resin such as polyethylene, polypropylene, or an ethylene-propylene copolymer; a vinyl resin such as polyvinyl chloride or polyvinylidene chloride; a polyamide resin; a sulfone-based resin; a polyether-ether ketone-based resin; an arylate-based resin; or a mixture of the above resins.

<Image display device>
An image display device according to an exemplary embodiment may include a substrate, a polarizing laminate according to an exemplary embodiment laminated on the substrate, and a display panel disposed below the substrate.

In some exemplary embodiments, the polarizing laminate, the substrate, and the display panel are positioned in sequence, and the polarizing laminate may have a surface exposed to the outside. This allows the polarizing laminate to be stacked such that the adhesive layer, the phase retardation layer, the polarizer, and the surface treatment layer are arranged in sequence from the substrate.

In addition, in some exemplary embodiments of the image display device, when the polarizing laminate further includes a protective film, an adhesive layer of the polarizing laminate may be laminated on one side of the substrate, and the display panel may be positioned at a distance from the other side of the substrate. In this case, the surface of the protective film may be exposed to the outside.

The substrate is provided as an insulating substrate, and in this case, the insulating substrate may be made of an insulating material such as glass, resin, etc. In addition, the substrate may be made of a material having flexibility so that it can be folded or bent, and may have a single-layer structure or a multi-layer structure.

The substrate may include thermoplastic resins such as polyester-based resins such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, and polybutylene terephthalate; cellulose-based resins such as diacetyl cellulose and triacetyl cellulose; polycarbonate-based resins; acrylic-based resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; styrene-based resins such as polystyrene and acrylonitrile-styrene copolymers; polyolefin-based resins such as polyethylene, polypropylene, polyolefins having a cyclo- or norbornene structure, and ethylene-propylene copolymers; vinyl chloride-based resins; amide-based resins such as nylon and aromatic polyamides; imide-based resins; polyethersulfone-based resins; sulfone-based resins; polyetheretherketone-based resins; polyphenylene sulfide-based resins; vinyl alcohol-based resins; vinylidene chloride-based resins; vinyl butyral-based resins; arylate-based resins; polyoxymethylene-based resins; epoxy-based resins, and may also include blends of the above thermoplastic resins.

The substrate may also include thermosetting or UV-curable resins such as (meth)acrylic, urethane, acrylic urethane, epoxy, and silicone. However, the material constituting the substrate may vary, and in some exemplary embodiments, the substrate may be formed of fiberglass reinforced plastic (FRP), etc.

Display Panel In an exemplary embodiment, the display panel of the image display device may include micro Light Emitting Diode (LED) modules. The "micro" in micro LED modules is used to refer to LED modules with a scale of 1-100 μm. However, exemplary embodiments are not necessarily so limited, and in some embodiments, smaller scale or larger scale LED modules may be used.

Further, in an exemplary embodiment, the micro LED module may have the form of an LED group or an LED array. The LED group or LED array is a form in which LED modules are coupled in parallel, and a seam may be formed between each LED module.

For example, an array containing micro LED modules can have a pitch of 10 μm×10 μm, or a pitch of 5 μm×5 μm. Also, at these densities, a 6-inch substrate can accommodate approximately 165 million micro LED modules with a pitch of 10 μm×10 μm. Or, a 6-inch substrate can accommodate approximately 660 million micro LED modules with a pitch of 5 μm×5 μm.

The micro LED module can be composed of multiple sub-pixels each including R (Red), G (Green), and B (Blue). Three sub-pixels of R (Red), G (Green), and B (Blue) compose one pixel (PA), and these pixels (PA) can be arranged in a continuous array. The micro LED module can also emit blue light, green light, or red light in combination with a wavelength conversion material such as a phosphor, and can also emit white light, ultraviolet light, etc.

In an exemplary embodiment, the display panel may be spaced apart from one side of the substrate. As used herein, the term "spaced apart" means that the two are not in direct contact with each other. For example, an air layer may be formed between the display panel and the substrate, and the display panel and the substrate may be spaced apart by the air layer.

In addition, a separate support member may be included to form an air layer between the substrate and the display panel. The support member may appropriately separate the display panel from the substrate so that the air layer can maintain a constant thickness. In addition, the outer periphery of the substrate and the display panel may be fixed to form and maintain the air layer. Separate packaging may be performed to fix the outer periphery.

In addition, in an exemplary image display device, the polarizing laminate, the substrate, and the display panel may be positioned in sequence. The polarizing laminate, the substrate, and the display panel may be prepared and assembled separately, or may be prepared simultaneously. Also, the polarizing laminate may be laminated on one surface of the substrate, and the other surface of the substrate may be oriented toward the display panel.

In addition, as LED modules become smaller, the area of the seams increases, and the seams may become visible to the user. The image display device according to the exemplary embodiment includes the polarizing laminate described above, thereby making it possible to suppress the visibility of the seams between the micro LED modules. As a result, the polarizing laminate suppresses the visibility of the seams, improving the optical characteristics of the image display device.

Hereinafter, the embodiments of the present invention will be described in more detail with reference to the drawings. However, the drawings attached to this specification are intended to illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to aid in a further understanding of the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited to only the matters depicted in the drawings.

Figures 1 and 2 are schematic cross-sectional views showing a polarizing laminate 100 according to an exemplary embodiment.

Referring to FIG. 1, the polarizing laminate 100 may include a surface treatment layer 110, a polarizer 120, a phase retardation layer 130, and an adhesive layer 140. In an exemplary embodiment, the surface treatment layer 110, the polarizer 120, the phase retardation layer 130, and the adhesive layer 140 may be sequentially laminated to form the polarizing laminate 100. The upper surface of the surface treatment layer 110 may be exposed to the outside, and the lower surface of the adhesive layer 140 may be exposed to the outside.

Referring to FIG. 2, the polarizing laminate 100 may further include a protective film 150 and a release layer 160. In addition, the protective film 150, the surface treatment layer 110, the polarizer 120, the phase retardation layer 130, the adhesive layer 140 and the release layer 160 may be sequentially laminated to form the polarizing laminate 100. In addition, the upper surface of the protective film 150 may be exposed to the outside, and the lower surface of the release layer 160 may be exposed to the outside.

Figure 3 is a schematic cross-sectional view of an image display device 1 including a polarizing laminate 100 according to an exemplary embodiment.

In an exemplary embodiment, the image display device 1 may include a polarizing laminate 100, a substrate 200, and a display panel 300. The polarizing laminate 100, the substrate 200, and the display panel 300 may be arranged in sequence to form the image display device 1. The display panel 300 may be arranged below the substrate 200, and an air layer 400 may be formed between the substrate 200 and the display panel 300 to separate the display panel 300 from the substrate 200.

Below, preferred examples are presented to aid in understanding the present invention, but these examples are merely illustrative of the present invention and do not limit the scope of the appended claims. It will be clear to those skilled in the art that various changes and modifications to the examples are possible within the scope of the scope and technical ideas of the present invention, and it is natural that such changes and modifications fall within the scope of the appended claims.

Examples and Comparative Examples Example 1. Preparation of Polarizing Laminate A methyl ethyl ketone (MEK) solvent was applied onto a triacetyl cellulose film (thickness 40 μm, TAC) using a Meyer bar so that the wet coating thickness was 5 μm, and then the film was dried with hot air at 40° C. for 1 minute to induce roughening. Then, a hard coat solution (DN-0081, manufactured by JSR Corporation) was applied using a Meyer bar so that the dry coating thickness was 5 μm, and the film was dried and cured with hot air at 70° C. for 1 minute to obtain a surface treatment layer. The haze value of the obtained surface treatment layer was 30%.

A transparent unstretched polyvinyl alcohol film (VF-PE 60μm, KURARAY) with a saponification degree of 99.9% or more was immersed in 30°C water (deionized water) for 2 minutes to swell, and then immersed in a 30°C dyeing aqueous solution containing 3.5mmol/L iodine and 2wt% potassium iodide for 4 minutes to dye. At this time, the polyvinyl alcohol film was stretched 1.3 times and 1.4 times in the swelling and dyeing steps, respectively. Next, it was crosslinked by immersing it for 2 minutes and 1 minute in a first crosslinking aqueous solution at 50°C containing 10wt% potassium iodide and 3.5wt% boric acid, and a second crosslinking aqueous solution at 50°C containing 1.0wt% citric acid and 1.0wt% zinc acetate, respectively. At this time, the crosslinking step was performed so that the total cumulative stretch ratio was 6.4 times. After crosslinking was completed, the polyvinyl alcohol film was dried in an oven at 70°C for 4 minutes to produce a polarizer.

The prepared surface treatment layer was laminated on the upper surface of the polarizer, and a 47 μm-thick retardation film (ZD12, manufactured by ZEON) was laminated on the lower surface of the polarizer. In addition, a 20 μm-thick adhesive layer (acrylic adhesive, manufactured by Lintec Corporation) was formed on the lower surface of the retardation layer to produce a polarizing laminate.

Example 2. Production of polarizing laminate A polarizing laminate was produced in the same manner as in Example 1, except that the composition of the solvent and the hard coat film were changed so that the haze value of the surface treatment layer was 21%.

Example 3. Production of polarizing laminate A polarizing laminate was produced in the same manner as in Example 1, except that the composition of the solvent and the hard coat film were changed so that the haze value of the surface treatment layer was 18%.

Example 4. Production of polarizing laminate A polarizing laminate was produced in the same manner as in Example 1, except that the composition of the solvent and the hard coat film were changed so that the haze value of the surface treatment layer was 35%.

Example 5. Production of polarizing laminate A polarizing laminate was produced in the same manner as in Example 1, except that the composition of the solvent and the hard coat film were changed so that the haze value of the surface treatment layer was 40%.

Comparative Example 1. Production of polarizing laminate A polarizing laminate was produced in the same manner as in Example 1, except that the surface treatment layer was omitted.

Comparative Example 2. Production of polarizing laminate A polarizing laminate was produced in the same manner as in Example 1, except that the composition of the solvent and the hard coat film were changed so that the haze value of the surface treatment layer was about 14%.

Comparative Example 3. Production of polarizing laminate A polarizing laminate was produced in the same manner as in Example 1, except that the composition of the solvent and the hard coat film were changed so that the haze value of the surface treatment layer was about 50%.

Comparative Example 4. Production of polarizing laminate A polarizing laminate was produced in the same manner as in Example 1, except that the composition of the solvent and the hard coat film were changed so that the haze value of the surface treatment layer was about 13%.

Comparative Example 5. Production of polarizing laminate A polarizing laminate was produced in the same manner as in Example 1, except that the composition of the solvent and the hard coat film were changed so that the haze value of the surface treatment layer was about 45%.

Experimental Example 1. Evaluation of Haze Value and Reflectance The haze value was measured using a spectrophotometer (HZ-1, manufactured by Suga Test Instruments Co., Ltd.) The display panel was a 5V 9W halogen bulb, the light receiving part was a silicon photocell (with a relative visibility filter), and the measurement was performed in accordance with JIS K-7136.

To measure the reflectance, a UV-2450 (Shimadzu Corporation) and an adapter MPC-2200 (Shimadzu Corporation) were used. The specular reflectance was measured at an incidence angle of 5° and an exit angle of 5° for wavelengths of 380 to 780 nm, and the average reflectance from 450 to 650 nm was calculated.

The haze values and reflectances of the surface treatment layers included in the polarizing laminates of the examples and comparative examples, measured by the above-mentioned methods, are shown in Table 1 below.

2. Evaluation of Seam Visibility and Color Difference An air layer was formed at a certain interval above the display panel including the micro LED module and the seam, and a transparent glass substrate was placed above the air layer. The width of the micro LED module was 50 μm, and the width of the seam was 0.1 μm. The refractive index of the transparent glass substrate was 1.51, the thickness of the transparent glass substrate was 520 μm, and the width of the air layer was 120 μm. An image display device was prepared by placing a polarizing laminate of the example or comparative example above the substrate.

The image display devices including the polarizing laminates of the Examples and Comparative Examples were visually inspected for visibility of the seam, and the color difference between the light-emitting part of the display panel and the seam was measured. The colorimeter used in the experiment was OSP-SP200 (manufactured by Olympus Corporation). ΔL ^* a ^* b ^* is a calculation of the color difference between the light-emitting part and the seam with respect to the CIE1976 (L ^* , a ^* , b ^* ) spatial color system. The evaluation results of the image display devices including the polarizing laminates of the Examples and Comparative Examples are shown in Table 2 below.

<Evaluation criteria>
○: The seam is visible. X: The seam is not visible.

3. Evaluation of clarity After setting the display panel so that a black and white pattern was repeated, the clarity of the image was evaluated by visual observation from the front and at a 45 degree angle. The evaluation criteria are as follows, and the evaluation results are shown in Table 3 below.

<Evaluation criteria>
◎ (Excellent): The image is clear and free of distortion. ○ (Fair): The pattern width changes slightly, but the pattern boundaries can be seen. X (Unsatisfactory): The pattern boundaries are so distorted that they cannot be seen.

Referring to Tables 1 and 2, it can be seen that in the exemplary embodiment, the surface treatment layer satisfies a predetermined haze value, thereby improving the visibility of the seams in the display panel. Therefore, by adopting the polarizing laminate according to the exemplary embodiment, it is possible to suppress the visibility of the seams by an external observer, and to prevent the degradation of optical characteristics due to the visibility of the seams in the image display device.

Also, referring to Tables 2 and 3, in the exemplary embodiment, it can be seen that the surface treatment layer satisfies a predetermined haze value, so that the seams in the display panel are not visible and clarity above the appropriate level is ensured. In addition, the image display device can achieve a clearer color. As a result, the polarizing laminate according to the exemplary embodiment can improve both the area and clarity of the image display device.

In contrast, in the cases of Comparative Examples 1, 2, and 4, the clarity was appropriate, but the seams were visible, and in the cases of Comparative Examples 3 and 5, the clarity was not achieved. Therefore, in the cases of Comparative Examples 1, 2, and 4, it can be confirmed that there is no or insufficient light scattering by the surface treatment layer, and in the cases of Comparative Examples 3 and 5, it can be confirmed that the clarity of the image display device is significantly reduced due to excessive light scattering.

Claims (10)

A polarizer;
a surface treatment layer formed on one surface of the polarizer and having a haze value of 15% to 40% and a reflectance of 2.5% or less;
a phase retardation layer formed on the other surface of the polarizer;
and an adhesive layer formed on the surface of the phase retardation layer. The polarizing laminate according to claim 1, further comprising a protective film laminated on the surface of the surface treatment layer. The polarizing laminate according to claim 1, wherein the surface treatment layer includes a hard coat film. The polarizing laminate according to claim 3, wherein the surface treatment layer is formed from a coating composition containing a (meth)acrylate compound. The polarizing laminate according to claim 3, wherein the surface treatment layer further contains an ion-conductive material. The polarizing laminate according to claim 1, wherein the thickness of the surface treatment layer is 1 to 20 μm. A substrate;
The polarizing laminate according to claim 1 laminated on the substrate;
and a display panel disposed below the substrate. The image display device according to claim 7, wherein the polarizing laminate is laminated such that the adhesive layer, the phase retardation layer, the polarizer, and the surface treatment layer are arranged in this order from the substrate. The image display device according to claim 7, wherein the display panel includes a micro light-emitting diode (LED) module. The image display device according to claim 9, wherein the micro LED module includes an array in which a plurality of micro LED chips are combined.