KR20190139193A - Optical stack structure integrated with polarizer and touch sensor and display device including the same - Google Patents

Abstract

The present invention provides a window, and an optical laminate including a polarizing layer and a touch sensor layer on any one surface of the window. The optical laminate has improved flexibility and mechanical reliability, and can be effectively applied as a window substrate of an image display device including a flexible display.

Description

Optical layer integrated with a polarizing layer and a touch sensor, and an image display device including the same {OPTICAL STACK STRUCTURE INTEGRATED WITH POLARIZER AND TOUCH SENSOR AND DISPLAY DEVICE INCLUDING THE SAME}

The present invention relates to a polarizing layer and a touch sensor-integrated optical laminate and an image display device including the same.

In recent years, display devices capable of displaying information including image images have been actively developed. The display device includes a liquid crystal display (LCD) device, an organic light emitting display (OLED) device, a plasma display panel (PDP) device, and a field emission display (FED) device. ) Devices and the like.

In the display device, for example, a window substrate may be disposed on the display panel such as an LCD panel and an OLED panel to protect the display panel from an external environment. The window substrate is formed of a glass material, and as the flexible display is recently developed, a transparent plastic material is used as the window substrate.

In addition, additional members of a display device such as a polarizer and a touch screen panel may be disposed between the window substrate and the display panel. For example, external light reflected from the electrode pattern of the display panel may be blocked by the polarizer. In addition, the user's command may be input through the touch screen panel.

However, as a plurality of layers or structures, such as the polarizing plate, the touch screen panel, and the window substrate, are stacked on the display panel, there is a limit in that the requirements in recent display devices such as flexible characteristics and thinning are sufficiently implemented. exist. In addition, as the plurality of layers or structures are stacked, sufficient flexibility cannot be easily secured while maintaining mechanical strength and stability.

For example, Korean Patent Laid-Open No. 2012-0076026 discloses a transparent substrate including a touch screen panel including a polarizing plate.

Korean Laid-Open Patent No. 2012-0076026 (2012.07.09)

One object of the present invention is to provide an optical laminate having improved mechanical reliability and flexible properties.

One object of the present invention is to provide an image display device including an optical laminate having improved mechanical reliability and flexible characteristics.

1. a window having a modified toughness of at least 10,000 Mpa%; And a polarizing layer disposed on one side of the window, wherein the modified toughness represents the product of stress (Mpa) and strain (%) at the break point of the stress-strain curve. sieve.

2. In the above 1, the Martens hardness of the window is 200N / mm ² or more at 10mN load, the optical laminate.

3. The optical laminate according to 1 above, wherein the window satisfies Equation 2 below:

[Equation 2]

(Friction coefficient / water contact angle) * 1,000 ≤2.5 / degree ( ^o ).

4. In the above 1, the thickness of the window is 40 to 150㎛, optical laminate.

5. The optical laminate according to the above 1, wherein the toughness of the entire optical laminate is 300 MPa% or more.

6. In the above 1, the thickness of the polarizing layer is 5 to 100㎛, the optical laminate.

7. In the above 1, wherein the polarization degree of the polarizing layer is 95% or more, the light transmittance is 42% or more, the optical laminate.

8. according to the above 1, wherein the polarizing layer comprises an elongated polarizer, the shrinkage force of the polarizing layer is 1.5N or less, the optical laminate.

9. In the above 1, further comprising a touch sensor layer disposed on the polarizing layer or between the window and the polarizing layer, the optical laminate.

10. The optical laminate according to 9 above, wherein the polarizing layer and the touch sensor layer are sequentially stacked from the one surface of the window.

11. a window having a modified toughness of at least 10,000 Mpa%; And a touch sensor layer disposed on one surface of the window, wherein the modified toughness represents a product of stress (Mpa) and strain (%) at the breakpoint of the stress-strain curve. Laminate.

12. In the above 11, the Martens hardness of the window is 200N / mm ² or more at 10mN load, the optical laminate.

13. The optical laminate of 11 above, wherein the window satisfies Equation 2 below:

[Equation 2]

(Friction coefficient / water contact angle) * 1,000 ≤2.5 / degree ( ^o ).

14. The optical laminate according to 11 above, wherein the window has a thickness of 40 to 150 μm.

15. The optical laminate according to 11 above, wherein the toughness of the entire optical laminate is 300 MPa% or more.

16. In the above 11, the thickness of the touch sensor layer is 1 to 100㎛, optical laminate.

17. The optical laminate according to 11 above, wherein the light transmittance of the touch sensor layer is 85% or more, and the touch sensor layer includes an electrode having a refractive index of 1.3 to 2.5.

18. The optical laminate of 11 above, further comprising a polarization layer disposed on the touch sensor layer or between the window and the touch sensor layer.

19. The optical stack according to 18 above, wherein the polarization layer and the touch sensor layer are sequentially stacked from the one surface of the window.

In the optical laminate according to the exemplary embodiments of the present invention, the window, the polarizing layer, and the touch sensor layer may be integrally combined and applied to the image display device. Therefore, the mechanical properties of each layer applied to the flexible display can be collectively controlled, and the occurrence of breakage, cracking, etc. can be suppressed, and an optical laminate having desirable flexibility can be easily implemented with high reliability.

According to exemplary embodiments, the optical laminate may have a modified toughness defined by the product of the stress and the strain at breakpoints above a certain value. Therefore, even when the operation such as bending and folding is repeated, defects such as delamination, cracking and tearing can be suppressed.

In addition, the optical laminate may be effectively applied to a thin flexible display as the polarizing layer and the touch sensor layer are integrated.

1, 2A and 2B are schematic cross-sectional views illustrating optical laminates in accordance with exemplary embodiments of the present invention.
3 through 7 are schematic cross-sectional views illustrating optical stacks in accordance with some example embodiments.
8 is a schematic cross-sectional view illustrating an optical stack in accordance with some example embodiments.
9 and 10 are schematic cross-sectional views illustrating a structure of a touch sensor layer according to some exemplary embodiments.
11 is a schematic cross-sectional view illustrating an electrode arrangement of a touch sensor layer according to some example embodiments.
12 is a cross-sectional view illustrating an optical stack according to exemplary embodiments of the present invention.
13 and 14 are schematic cross-sectional views illustrating optical stacks in accordance with some example embodiments.
15 through 17 are schematic cross-sectional views illustrating optical stacks in accordance with some example embodiments.
18 is a graph showing crystal toughness of an optical laminate in accordance with example embodiments.

According to embodiments, an optical laminate including a window and a polarizing layer and a touch sensor layer on one surface of the window is provided. The optical laminate is integrated with a polarizing layer and a touch sensor layer, for example, may have a modified toughness above a certain threshold and have improved flexibility and durability. Embodiments of the present invention also provide an image display device including the optical stack.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Although the following describes preferred embodiments of the present invention, these embodiments are only illustrative of the present invention and are not intended to limit the scope of the appended claims, and various modifications to the embodiments within the scope and spirit of the present invention. Modifications and variations are apparent to those skilled in the art, and such variations and modifications are naturally within the scope of the appended claims.

<Optical laminate>

1, 2A and 2B are schematic cross-sectional views illustrating optical laminates in accordance with exemplary embodiments of the present invention. The optical laminate may be applied to, for example, a laminate of windows of an image display device such as a flexible display.

Referring to FIG. 1, the optical stack may include a window 100, and a polarization layer 110 and a touch sensor layer 130 disposed on one surface of the window 100.

The window 100 may be provided as a window film or an optical substrate of the optical laminate. The optical base material may be applied to, for example, an LCD device, an OLED device, a touch screen panel (TSP), and the like, and may include a material having durability against external impact and transparency that a user can see. In addition, the optical substrate may include a plastic material or a polymer material having a predetermined flexibility, and in this case, the display device to which the optical laminate is applied may be provided as a flexible display.

For example, the optical substrate may be polyimide (PI), polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (polyethyelenen napthalate) : PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyallylate, polycarbonate (PC, polycarbonate), cellulose triacetate (TAC), cellulose acetate pro Cionate (cellulose acetate propionate, CAP) and the like. These may be used alone or in combination of two or more.

The window 100 includes one surface 100b and the other surface 100a. For example, one surface 100b and the other surface 100a may correspond to an upper surface and a lower surface of the window 100, respectively.

The other surface 100a of the window 100 may be disposed toward the viewer's side when the optical stack is applied to the image display device. For example, an image is implemented to the user on the other surface 100a of the window 100, and a user's command (eg, via a touch) may be input. One surface 100b of the window 100 faces the display panel, for example, and additional layers and / or structures of the optical stack may be stacked or disposed on the surface 100b.

As illustrated in FIG. 1, the polarization layer 110 may be disposed on one surface 100b of the window 100, and the touch sensor layer 130 may be disposed on the polarization layer 110.

The polarizing layer 110 may include an elongated or coated polarizer. The touch sensor layer 130 may be bonded to the polarization layer 110. The touch sensor layer 130 may include electrode patterns for converting a user's touch signal input through the other surface 100a of the window 100 into an electrical signal. More detailed configurations of the touch sensor layer 130 will be described later with reference to FIGS. 9 and 10.

According to example embodiments, an adhesive layer may be formed between at least one of the polarization layer 110 and the window 100, or between the touch sensor layer 130 and the polarization layer 110.

As used herein, the term "adhesive layer" is used to encompass the adhesive layer and the adhesive layer. The adhesive layer can be formed using a pressure sensitive adhesive (PSA) composition or an optically clear adhesive (OCA) composition.

In some embodiments, as illustrated in FIG. 6, a first adhesive layer 120a may be formed between the polarizing layer 110 and the window 100. In one embodiment, after forming the first adhesive layer 120a on one surface 100b of the window 100, the polarizing layer 110 is bonded to the window 100 through the first adhesive layer 120a. You can. In an exemplary embodiment, the first adhesive layer 120a may be formed on the polarizing layer 110 and then bonded to the window 100.

In some embodiments, as illustrated in FIG. 8, the touch sensor layer 130 may be bonded to the polarization layer 110 through the second adhesive layer 120b.

The adhesive layer may have an appropriate adhesive force to prevent peeling, bubbles, etc. when bending occurs in the optical laminate, and may have viscoelastic properties applicable to a flexible display. In some embodiments, the adhesive layer may be formed using an acrylate-based PSA composition in view of the above-described aspect. For example, the PSA composition may include a (meth) acrylic acid ester copolymer, a crosslinking agent, and a solvent.

The type of the crosslinking agent is not particularly limited and may be appropriately selected and used among those commonly used in the art. For example, the crosslinking agent may include a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, a dialdehyde, a methylol polymer, and the like, and preferably a polyisocyanate compound may be used.

The solvent may include a conventional solvent used in the field of resin composition, for example, alcohol-based (methanol, ethanol, isopropanol, butanol, propylene glycol methoxy alcohol, etc.), ketone-based (methyl ethyl ketone, methyl butyl Ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, etc.), acetate type (methyl acetate, ethyl acetate, butyl acetate, propylene glycol methoxy acetate, etc.), cellosolve type (methyl cellosolve, ethyl cellosolve, propyl) Cellosolves, etc.), hydrocarbon-based (normal hexane, normal heptane, benzene, toluene, xylene, etc.) may be used. These may be used alone or in combination of two or more thereof.

Referring to FIG. 2A, the window 100 may further include a hard coating layer 104. According to example embodiments, the window 100 may include a laminated structure of the optical substrate 102 and the hard coating layer 104 described above.

For example, the optical substrate 102 may include one surface 102b and the other surface 102a, and the hard coating layer 104 may be formed on the other surface 102a of the optical substrate 102. In this case, the surface of the hard coating layer 104 may be exposed to the user's viewing side. The polarization layer 110 and the touch sensor layer 130 may be stacked on one surface 102b of the optical substrate 102.

The hard coating layer 104 is formed using a hard coating composition including a photocurable compound, a photoinitiator, and a solvent, thereby additionally securing excellent flexibility, wear resistance, and surface hardness of the window 100.

The photocurable compound may include, for example, a siloxane compound, an acrylate compound, a compound having a (meth) acryloyl group or a vinyl group. These may be used alone or in combination of two or more thereof.

Examples of the siloxane compound may include a polydimethylsiloxane (PDMS) compound. The siloxane compound may contain an epoxy group such as a glycidyl group. Accordingly, crosslinking or curing through epoxy ring opening may be promoted by light irradiation.

Examples of the acrylate-based compound include dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate And (meth) acrylate containing an oxyethylene group, ester (meth) acrylate, ether (meth) acrylate, epoxy (meth) acrylate, melamine (meth) acrylate, and the like.

Examples of the compound having a (meth) acryloyl group or a vinyl group include (meth) acrylic acid esters, N-vinyl compounds, vinyl-substituted aromatics, vinyl ethers and vinyl esters.

The photoinitiator is not particularly limited as long as the photoinitiator generates ions, Lewis acids or radicals by irradiation with active energy rays such as visible light, ultraviolet light, X-rays or electron beams to initiate the polymerization reaction of the photocurable compound. Examples of the photoinitiator include onium salts such as aromatic diazonium salts, aromatic iodonium salts and aromatic sulfonium salts, acetphenone compounds, benzoin compounds, benzophenone compounds, thioxanthone compounds and the like.

The solvent may use a solvent substantially the same as or similar to that used in the PSA composition, and is not particularly limited.

In some embodiments, the hard coating composition may further include a UV absorber. The ultraviolet absorbent may be used without particular limitation as long as it is a compound capable of absorbing an ultraviolet wavelength of about 380 nm or less. In some embodiments, the ultraviolet absorber may include a benzoxazinone-based compound, a triazine-based compound, a benzotriazole-based compound, or a benzophenone-based compound. . These may be used alone or in combination of two or more. Accordingly, the UV transmittance is reduced by the hard coating layer 104 to improve the optical properties and visible light transmittance of the optical laminate.

1 and 2A, a single layer structure of the optical substrate 102 may be applied as the window 100, and a multilayer structure of the hard coating layer 104 and the optical substrate 102 may be applied.

In some embodiments, the window 100 may further include an additional hard coating layer formed on one surface 102b of the optical substrate 102. In this case, the window 100 may include a first hard coat layer-based film-second hard coat layer stacked structure.

Referring to FIG. 2B, the window 100 may further include at least one functional layer applied to an image display device such as an ultraviolet blocking layer, a scattering prevention layer, a fingerprint prevention layer, or the like. In some embodiments, a laminate structure including the hard coating layer 104 and the functional layer 104a shown in FIG. 2A may be disposed on the other surface 102a of the optical substrate 100.

3 through 7 are schematic cross-sectional views illustrating optical stacks in accordance with some example embodiments.

Referring to FIG. 3, the polarizing layer may include a coated polarizer. For example, the polarization layer may include the liquid crystal layer 110a.

In some embodiments, the liquid crystal layer 110a may be formed by applying a liquid crystal coating composition on one surface 100b of the window 100. In this case, the liquid crystal layer 110a may directly contact the window 100. The liquid crystal coating composition may include a reactive liquid crystal compound and a dichroic dye.

The reactive liquid crystal compound may include a reactive mesogen (RM) capable of expressing liquid crystal, and a monomer molecule including a polymerizable terminal functional group and a liquid crystal phase after a crosslinking reaction by heat or light. When the reactive liquid crystal compound is polymerized by light or heat, a polymer network may be formed while the liquid crystal array is maintained. By utilizing the above-mentioned reactive liquid crystal compound, a polarizer in the form of a thin film having improved mechanical and thermal stability may be formed while maintaining optical anisotropy or dielectric constant of the liquid crystal.

The dichroic dye is a component included in the liquid crystal coating composition to impart polarization characteristics, and has a property in which absorbance in the major axis direction of the molecule and absorbance in the minor axis direction are different. Non-limiting examples of the dichroic dye may include an acridine pigment, an oxazine pigment, a cyanine pigment, a naphthalene pigment, an azo pigment, an anthraquinone pigment, and the like. These may be used alone or in combination of two or more.

The liquid crystal coating composition further includes a solvent capable of dissolving the reactive liquid crystal compound and the dichroic dye. For example, propylene glycol monomethyl ether acetate (PGMEA), methyl ethyl ketone (MEK), xylene and chloroform And the like can be used. The liquid crystal coating composition may further include a leveling agent, a polymerization initiator, and the like within a range that does not impair polarization characteristics of the coating film.

Referring to FIG. 4, the polarization layer 110 may include a liquid crystal layer 110a and an alignment layer 110b. For example, the liquid crystal layer 110a may be formed on the alignment layer 110b.

For example, after the alignment film coating composition containing an alignment polymer, a photopolymerization initiator and a solvent is applied and cured on the window 100 to form the alignment film, the liquid crystal coating composition is coated and cured on the alignment film to align the alignment film. The polarizing layer 110 including the 110b and the liquid crystal layer 110a may be formed.

The alignment polymer may include, for example, a polyacrylate resin, a polyamic acid resin, a polyimide resin, a polymer including a cinnamate group, or the like.

Referring to FIG. 5, the polarization layer 110 may further include an overcoat layer 111. For example, the overcoat layer 111 may be formed on the upper surface of the liquid crystal layer 110a and may face the alignment layer 110b.

In some embodiments, as shown in FIG. 5, the protective film 113 may be laminated on the overcoat layer 111. In this case, the polarizing layer 110 may include a laminated structure of an alignment layer, a liquid crystal layer, an overcoat layer, and a protective film, and mechanical durability may be further improved while maintaining transmittance.

The overcoat layer 111 may substantially function together as an adhesive layer for bonding the protective film 113. In one embodiment, an adhesive layer may be further formed between the overcoat layer 111 and the protective film 113.

In some embodiments, the protective film 113 may include an optical functional layer. A retardation film is mentioned as an example of the said optical function layer. The retardation film may be included as a functional layer for retarding the phase of light passing through the liquid crystal layer 110a. The material of the retardation film is not particularly limited, and may include a gradient stretched resin film, a liquid crystal coating layer, and the like.

For example, the retardation film may comprise a λ / 4 film. The retardation film may have, for example, a multilayer structure in which a λ / 4 film and a λ / 2 film are laminated.

In some embodiments, the protective film 113 may further be laminated with an optical functional layer, such as a retardation film.

Referring to FIG. 6, the polarization layer 110 may include an elongated polarizer 114. For example, the polarization layer 110 may include the first protective film 112 and the stretched polarizer 114, and the polarization layer 110 may be provided as a substantially stretched polarizer.

The first protective film 112 may include, for example, polyester resins such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, and polybutylene terephthalate; Cellulose resins such as diacetyl cellulose and triacetyl cellulose; Polycarbonate resins; Acrylic resins such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Cyclic olefin polymer (COP) and the like.

The stretched polarizer 114 may include, for example, a stretched polyvinyl alcohol (PVA) -based resin. The polyvinyl alcohol-based resin may be preferably a polyvinyl alcohol-based resin obtained by saponifying a polyvinyl acetate-based resin. As polyvinyl acetate type resin, the copolymer etc. of vinyl acetate and the other monomer copolymerizable with this besides the polyvinyl acetate which is a homopolymer of vinyl acetate are mentioned. Examples of the other monomers include unsaturated carboxylic acid type, unsaturated sulfonic acid type, olefin type, vinyl ether type, and acrylamide monomer having an ammonium group. The polyvinyl alcohol-based resin may be modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes.

In example embodiments, a first adhesive layer 120a is formed on the first protective film 112 of the polarizing layer 110, and the polarizing layer 110 is formed on the first adhesive layer 120a. It may be bonded to the film 100.

Referring to FIG. 7, the polarization layer 110 may further include a second protective film 116 formed on an upper surface of the stretched polarizer 114. Accordingly, the polarizing layer 110 may be provided as a polarizing plate including the first and second protective films 112 and 116, and the stretched polarizer 114 sandwiched therebetween.

In one embodiment, the second protective film 116 may include a material substantially the same as or similar to the first protective film 112.

In one embodiment, the second protective film 116 may include an optical functional layer. The retardation film mentioned above is mentioned as an example of the said optical function layer.

In some embodiments, the second protective film 116 includes a material substantially the same as or similar to that of the first protective film 112, and an optical functional layer, such as a retardation film, is formed on the second protective film 116. May be further stacked

8 is a schematic cross-sectional view illustrating an optical stack in accordance with some example embodiments. 9 and 10 are schematic cross-sectional views illustrating a structure of a touch sensor layer according to some exemplary embodiments. 11 is a schematic cross-sectional view illustrating an electrode arrangement of a touch sensor layer according to some example embodiments.

Referring to FIG. 8, the touch sensor layer 130 may be bonded to the polarization layer 110 through the second adhesive layer 120b. Referring to FIG. 9, the touch sensor layer 130 may include a substrate 200 and an electrode 220 disposed on the substrate 200. In addition, an insulating layer 230 covering the electrodes 220 may be formed on the substrate 2000.

The substrate 200 may include a flexible resin film such as polyimide. The electrodes 220 may include a sensing electrode designed to sense a touch through a change in capacitance, and a pad electrode for signal transmission.

For example, the electrode 220 may include a metal, a metal wire (eg, metal nanowire), or a transparent conductive oxide.

The metal is silver (Ag), gold (Au), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), chromium (Cr), titanium (Ti), tungsten (W), niobium ( Nb), tantalum (Ta), vanadium (V), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn), or alloys thereof. These may be used alone or in combination of two or more.

Examples of the transparent conductive oxide include indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium tin oxide (CTO), and the like.

In one embodiment, electrode 220 may comprise a stacked structure, such as a transparent metal oxide-metal wire, or a transparent metal oxide-metal (or metal wire) -transparent metal oxide.

In some embodiments, the touch sensor layer 130 may include a touch sensor driven in a mutual-capacitance manner. In this case, the sensing electrode may include first sensing electrodes and second sensing electrodes arranged to intersect in different directions (for example, X and Y directions) to sense a touch position of the user.

For example, the sensing lines may be defined by connecting unit patterns with each other, and a plurality of sensing lines may be arranged. The second sensing electrodes may include unit patterns that are physically spaced apart from each other. For example, a bridge electrode for electrically connecting neighboring second sensing electrodes with the first sensing electrode therebetween may be further included. In this case, the insulating layer 230 may be provided as a support pattern of the bridge electrode, and may include an insulating pattern for insulating the first and second sensing electrodes from each other.

In some embodiments, the touch sensor layer 130 may include a touch sensor driven in a self-capacitance manner. In this case, the electrodes 220 may include unit patterns that are physically spaced apart from each other. The unit patterns may be electrically connected to the driving circuit through traces or wiring lines, respectively.

The unit patterns may be formed, for example, by patterning a mesh metal electrode into a polygonal shape.

The insulating layer 230 may cover the electrodes 220 on the substrate 200. The insulating layer 230 may include, for example, an inorganic insulating material such as silicon oxide, or a transparent organic material such as acrylic resin.

In an exemplary embodiment, the touch sensor layer 130 may be bonded to the polarization layer 110 through the second adhesive layer 120b toward the substrate 200. In an embodiment, the touch sensor layer 130 may be bonded to the polarization layer 110 toward the insulating layer 130.

Referring to FIG. 10, the touch sensor layer 130 may include a separation layer 205, an intermediate layer 210, an electrode 220, and an insulating layer 230.

The separation layer 205 may include a polymer organic film, and includes, but is not limited to, polyimide polymer, polyvinyl alcohol polymer, polyamic acid polymer, polyamide polymer, polyethylene polymer, polystyrene polymer, polynovo Nene polymer, phenylmaleimide copolymer system polymer, polyazobenzene polymer, polyphenylene phthalamide polymer, polyester polymer, polymethyl methacrylate polymer, polyarylate polymer, cinnamate polymer, coumarin It may include a polymer material, such as a polymer, a phthalimidine polymer, a chalcone (chalcone) polymer, an aromatic acetylene polymer. These can be used individually or in combination of 2 or more types.

In some embodiments, the separation layer 205 is formed on a carrier substrate (not shown), such as a glass substrate, and after the electrode 220 and the insulating layer 230 are formed, a separation process from the carrier substrate is performed. Can be formed to facilitate.

The intermediate layer 210 may be formed to protect the electrodes 220 of the touch sensor layer 130 and match the refractive index with the electrodes 220. For example, the intermediate layer 210 may be formed to include an inorganic insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or the like, or a polymer-based organic insulating material.

In some embodiments, either the separation layer 205 or the intermediate layer 210 may be omitted.

An adhesive layer 120 may be formed on the touch sensor layer 130, and a protective film 240 may be attached onto the adhesive layer 120. For example, the carrier substrate may be removed after the protective film 240 is attached. Thereafter, after removing the protective film 240, the touch sensor layer 130 may be laminated on the polarization layer 110 using the adhesive layer 120.

In some embodiments, the adhesive layer 120 may be removed together with the protective film 240, and the adhesive layer for integration into the optical stack may be formed on the insulating layer 230.

In some embodiments, the substrate may be further bonded to the separation layer 205 after the carrier substrate is peeled off.

In some embodiments, the touch sensor layer 130 may be applied in a substantially inorganic type. In this case, the electrodes 220 may be directly formed on the polarization layer 110.

In some embodiments, the separation layer 205 and / or the intermediate layer 210 substantially function as a substrate and may be integrated into an optical stack.

Referring to FIG. 11, the electrodes included in the touch sensor layer may be dispersed on the upper and lower surfaces of the polarization layer 110.

According to example embodiments, first electrodes 220a may be arranged on the top surface of the polarization layer 110, and second electrodes 220b may be arranged on the bottom surface of the polarization layer 110. have.

For example, the first electrodes 220a may include sensing electrodes arranged along a row direction (eg, x direction) to form a sensing line. The second electrodes 220b may include sensing electrodes arranged along a column direction (eg, the y direction) to form a sensing line.

As the first electrode 220a and the second electrode 220b are disposed on different planes or levels, a bridge electrode for insulating the first and second electrodes 220a and 220b from each other may be omitted. In addition, the polarization layer 110 may be utilized as a substrate of the touch sensor layer 130.

12 is a cross-sectional view illustrating an optical stack according to exemplary embodiments of the present invention. Referring to FIG. 12, the touch sensor layer 130 and the polarization layer 110 may be sequentially disposed from one surface 100b of the window 100.

As described with reference to FIGS. 2A and 2B, the window 100 may include an optical substrate and a hard coating layer, or a stacked structure of the optical substrate and the functional layer.

According to the embodiment illustrated in FIG. 12, the touch sensor layer 130 may be disposed closer to the viewer's view side or the touch input surface. Thus, the sensitivity of touch sensing and signal transmission can be further improved.

13 and 14 are schematic cross-sectional views illustrating optical stacks in accordance with some example embodiments.

Referring to FIG. 13, in the window-touch sensor layer-polarizing layer structure illustrated in FIG. 12, the touch sensor layer 130 may be bonded to the window 100 through the first adhesive layer 120a.

As described with reference to FIG. 9, the touch sensor layer 130 may include a substrate and an electrode disposed on the substrate. In some embodiments, the touch sensor layer 130 may be made of a substantially inorganic type. In this case, the electrodes may be directly formed on the window 100. In some embodiments, the separation layer 205 and the intermediate layer 210 may be substantially provided as a substrate as shown in FIG. 10.

In an embodiment, as illustrated in FIG. 11, the electrodes of the touch sensor layer 130 may be distributed on the top and bottom surfaces of the polarization layer 110.

The polarization layer 110 may include a coated polarizer as described with reference to FIG. 3, and may include, for example, an alignment layer and a liquid crystal layer as illustrated in FIG. 4. In some embodiments, as illustrated in FIG. 5, the polarization layer 110 may include an overcoat layer formed on the liquid crystal layer.

Referring to FIG. 14, a second adhesive layer 120b may be included between the touch sensor layer 130 and the polarization layer 110.

In some embodiments, the polarizing layer 110 may be a stretched polarizing plate including the first protective film 112 and the stretched polarizer 114.

In some embodiments, as shown in FIG. 7, the polarization layer 110 may further include a second protective film 116 bonded on the stretched polarizer 114. The second protective film 116 may include, for example, an optical functional layer such as a retardation film. The optical functional layer may be further laminated on the second protective film 116.

15 through 17 are schematic cross-sectional views illustrating optical stacks in accordance with some example embodiments. For example, FIGS. 15 to 17 show examples of an optical stack including a light shielding pattern.

Referring to FIG. 15, the light blocking pattern 107 may be formed on an outer portion of one surface 100b of the window 100. For example, the light shielding pattern 107 may be provided as a bezel of an optical stack or an image display device.

The light shielding pattern 107 includes a color pattern such as a white pattern and a black pattern, and may have a stacked structure of multiple patterns of different colors. For example, the light blocking pattern 107 may be formed of a resin material such as acrylic resin, epoxy resin, polyurethane, silicone, etc., in which pigments and / or dyes for color realization are mixed.

The first adhesive layer 120a may be formed on the surface of the light blocking pattern 107 and one surface 100b of the window 100. In FIG. 15, the top surface of the first adhesive layer 120a is shown to be flat, but the first adhesive layer 120a is conformally formed along the surface of the light shielding pattern 107 and one surface 100b of the window 100. May be

For example, the polarizing layer 110 described with reference to FIG. 6 may be bonded to the first adhesive layer 120a toward the first protective film 112, and the second adhesive layer 120b may be disposed on the polarizing layer 110. Through the touch sensor layer 130 may be stacked.

Referring to FIG. 16, the light blocking pattern 107 may be horizontally overlapped with the polarization layer 110 or positioned at substantially the same level as the polarization layer 110. For example, the polarization layer 110 may be a coated polarizer including a liquid crystal layer, and as illustrated in FIG. 16, the surface of the light shielding pattern 107 and the surface 100b of the window 100 may be coated. Can be.

In example embodiments, the polarization layer 110 may be formed on the sidewall of the light blocking pattern 107 and the one surface 100b of the window 100, and may not extend on the top surface of the light blocking pattern 107.

Referring to FIG. 17, the light blocking pattern 107 may be horizontally overlapped with the touch sensor layer 130 or positioned at substantially the same level as the touch sensor layer 130.

For example, the light blocking pattern 107 may be disposed on the polarizing layer 110, and the adhesive layer 120 may be formed on the light blocking pattern 107 and the polarizing layer 110. The touch sensor layer 130 may be inserted into the opening defined by, for example, the light blocking pattern 107 through the first adhesive layer 130. The polarizing layer 110 may have a structure including a coating polarizer described with reference to FIGS. 3 to 5, and may have a stretched polarizing plate structure described with reference to FIGS. 6 and 7.

Pads, traces, or wires included in the touch sensor layer 130 may overlap the light blocking pattern 107 in a vertical direction.

The optical stack according to the embodiments of the present invention described above may have a structure in which a polarizer and a touch sensor are integrated with a window or an optical substrate. Therefore, the optical laminate may control or adjust the mechanical properties for securing flexibility, reliability, and durability necessary for applying to a flexible display such as, for example, a flexible OLED device.

Therefore, it is possible to secure desirable characteristics such as flexibility, hardness, peeling resistance, and the like more effectively than independently controlling the physical properties of each individual structure included in the flexible display.

In the optical stack according to the exemplary embodiments described above with reference to FIGS. 1 to 17, the amended touchness of the entire optical stack may be adjusted. In example embodiments, the optical laminate may satisfy Equation 1 below.

[Equation 1]

300 MPa% ≤ crystal toughness

In Equation 1, "modification toughness" means the product of stress (Mpa) and strain (%) at the break point of the stress-strain curve of the optical laminate.

The stress-strain curve is a stress applied to the laminate through the tensile test of the laminate including the polymer material, and the strain of the laminate exhibited in response to the stress. It is a graph showing the relationship between. The stress-strain curve may be referred to as a curve indicating the change in magnitude of the stress required as the strain of the polymer material increases.

18 is a graph showing crystal toughness of an optical laminate in accordance with example embodiments. Referring to FIG. 18, the x-axis represents the strain (%) and the y-axis represents the stress (Mpa) according to the strain. A portion indicated by circles in the graph of FIG. 18 corresponds to a fracture point at which fracture or tear occurs as the deformation of the laminate increases. The modified toughness of Equation 1 is a product of x value (strain) and y value (stress) at the break point, and corresponds to the area of a rectangle indicated by a thick line. 18 shows an example in which the crystal toughness is 389.7 Mpa%.

According to exemplary embodiments, by designing the modified toughness of the optical laminate to about 300 Mpa% or more, it is possible to secure resistance, cracking resistance, and peeling resistance to repeated bending fatigue with high hardness. When the modified toughness of the optical laminate is less than about 300 Mpa%, sufficient flexibility may not be secured, and interlayer peeling and cracking may occur when applied to a flexible display. In some embodiments, the modified toughness of the optical laminate may be about 400 Mpa% or more, in which case improved flexibility may be achieved.

The higher the modified toughness, the better the flexibility improvement effect, and the upper limit is not particularly limited, but for economic reasons it may be adjusted to 1,000 MPa% or less, preferably 800 MPa% or less.

According to the exemplary embodiments described above, each layer or each structure of the optical stack may have the following optical, mechanical, and electrical properties.

The window 100 of the optical stack may itself have a quartz toughness of about 10,000 Mpa% or more. As used herein, the term “window” refers to, for example, the optical substrate described with reference to FIG. 1, or the optical substrate 102, hard coat layer 104, and / or functional layer described with reference to FIGS. 2A and 2B. It may mean a laminated structure of 104a). As described above, the window may include a first hard coating layer and a second hard coating layer respectively formed on one side and the other side of the optical substrate.

In one embodiment, the window may have a pencil hardness of 3H or more at a load of 1kg to protect the outer surface of the image display device.

In one embodiment, the water contact angle of the window may be about 105 degrees ( ^o ) or more. Within this range, moisture resistance, antifouling property, anti blocking property, etc. of the window film may be improved.

In one embodiment, the impact force of the window may be about 70% or less of the glass substrate of the same thickness. Therefore, the impact resistance of the optical laminate is improved, and the phenomenon of breaking against external impact can be suppressed.

In one embodiment, the window has improved scratch resistance and may satisfy the following Equation 2.

[Equation 2]

(Friction coefficient / water contact angle) * 1,000 ≤2.5 / degree ( ^o )

In one embodiment, the window may satisfy the following equation (3).

[Equation 3]

Martens Hardness (HM) ≥ 200 N / mm ²

In Equation 3, the Martens hardness represents the value measured at a 10 mN load.

In some embodiments, the window satisfies Equation 2 and 3 together, thereby improving the surface hardness of the window, thereby ensuring proper slip resistance and improving scratch resistance.

In one embodiment, the window may have a transmission of about 15% or less for about 380 nm ultraviolet wavelength. The term "380 nm ultraviolet wavelength" as used herein may encompass not only exactly 380 nm wavelength but also ultraviolet wavelengths of less than 380-390 nm. For example, the UV transmittance in the above range may be secured through the functional layer 104a including the ultraviolet absorber or the ultraviolet blocking layer included in the hard coating layer 104. Therefore, the light resistance of the polarizing layer disposed on the window can be improved.

In one embodiment, the thickness of the window may be about 40 to 150㎛.

The polarization layer 110 included in the optical laminate may include a coated polarizer or an elongated polarizer as described above.

In example embodiments, the polarization degree Py of the polarization layer may be about 95% or more, and the light transmittance may be 42% or more. In addition, when the polarizing layer is a stretched polarizing plate, the shrinkage force of the polarizing layer may be about 1.5N or less. Therefore, a high quality image having desired polarization characteristics can be realized while ensuring dimensional stability.

For example, the shrinkage force may be measured as an absolute value of the force to be contracted when left for 2 hours at 80 ° C for a sample having a width of 2mm x length of 50mm (MD direction). For example, the retraction force can be measured using a device such as Q800, such as TA-Instrument.

In one embodiment, the polarizing layer may have a thickness of about 100 μm or less, for example, about 5 to 100 μm.

The sheet resistance of the electrode 220 of the touch sensor layer 130 included in the optical stack may be about 500 Ω / □ or less. In addition, the surface roughness of the electrode may be about 1.5 nm or less. Accordingly, it is possible to secure improved sensing sensitivity and signal uniformity.

In one embodiment, the light transmittance of the touch sensor layer is about 85% or more, preferably about 89% or more. In addition, the refractive index of the electrode 220 of the touch sensor layer may be about 1.3 to 2.5. Thereby, visual recognition of the electrode 220 can be prevented, without the optical characteristic or transmittance | permeability of the optical laminated body by the said touch sensor layer falling.

In one embodiment, the thickness of the touch sensor layer may be about 1 to 100㎛.

As described above, the optical laminate may include one or more adhesion layers, and the thickness of each adhesion layer may be about 5 to 100 μm.

According to exemplary embodiments, the total thickness of the optical laminate may be designed to 600 μm or less.

<Image display device>

Embodiments of the present invention provide an image display device including the optical laminate described above. The optical stack may be combined with a display panel included in an OLED device, an LCD device, or the like. The display panel may include a pixel circuit including a thin film transistor (TFT) arranged on a substrate, and a pixel portion or a light emitting portion electrically connected to the pixel circuit.

For example, an optical stack, as described with reference to FIGS. 1 through 17, may be disposed on the display panel. The optical stack may be provided as a window substrate or a window stack exposed to the outside of the image display device.

The image display device may be a flexible display, and mechanical defects or damages such as cracking, peeling, and breaking may be suppressed by the improved flexibility and durability characteristics of the optical laminate even during operation such as folding or bending.

Hereinafter, the specific experimental examples, the characteristics of the optical laminate of the present invention will be described in more detail. The examples included in the following experimental examples are merely illustrative of the present invention and are not intended to limit the appended claims, nor are comparative examples necessarily included to limit the scope of the present application. It is apparent to those skilled in the art that various changes and modifications to the embodiments can be made within the scope and spirit of the present invention, and such variations and modifications are within the scope of the appended claims.

Examples and Comparative Examples

Example 1

(1) Preparation of Hard Coating Composition

35 parts by weight of a 6 functional acrylate (PU620D, Miwon Specialty Chemical) as a photocurable resin, 10 parts by weight of hexanediol diacrylate, 2.7 parts by weight of 1-hydroxycyclohexyl-phenyl-ketone as a photoinitiator, and propylene glycol mono as a solvent 52 parts by weight of methyl ether, and 0.3 parts by weight of BYK-UV3570 (BYK) as a leveling agent were mixed in a stirrer and filtered using a PP filter to prepare a hard coating composition.

(2) window manufacturing

The hard coating composition prepared above was coated on an optical polyimide film having a thickness of 80 μm to have a thickness of 10 μm, dried at 80 ° C. for 1 minute, and cured at a light amount of 300 mJ / cm 2 in a high pressure mercury lamp. By forming a coating layer, a window was produced.

(3) window-polarizing plate laminate

A first adhesive layer having a thickness of 25 μm was formed on the other surface of the surface of the window on which the hard coating layer was formed. In addition, a polyvinyl alcohol (PVA) polarizer having a thickness of 20 µm was attached to an 80 µm triacetyl cellulose (TAC) film as a protective film, and bonded to the protective film and the polarizer in order on the first adhesive layer. A polarizing plate laminate was prepared.

Example 2

35 parts by weight of a 6 functional acrylate (PU620D, Miwon Specialty Chemical) as a photocurable resin and 10 parts by weight of a propylene glycol monomethyl ether dispersed 15 nm reactive silica sol (40% solids), 1-hydroxycyclohexyl-phenyl- as a photoinitiator 2.7 parts by weight of ketone, 52 parts by weight of propylene glycol monomethyl ether as a solvent, and 0.3 parts by weight of BYK-UV3570 (BYK) as a leveling agent were mixed in a stirrer and filtered using a PP filter to prepare a hard coating composition. .

Using the hard coating composition, a window-polarizing plate laminate was prepared through the same process as described in (2) and (3) of Example 1.

Example 3

25 parts by weight of a 6 functional acrylate (PU620D, Miwon Specialty Chemical) and 20 parts by weight of propylene glycol monomethyl ether dispersed 15 nm reactive silica sol (40% solids) as a photocurable resin, 1-hydroxycyclohexyl-phenyl- as a photoinitiator 2.7 parts by weight of ketone, 52 parts by weight of propylene glycol monomethyl ether as a solvent, and 0.3 parts by weight of BYK-UV3570 (BYK) as a leveling agent were mixed in a stirrer and filtered using a PP filter to prepare a hard coating composition. .

Using the hard coating composition, a window-polarizing plate laminate was manufactured through the same process as described in (2) and (3) of Example 1.

Example 4

A window-polarizing plate laminate was manufactured through the same process as described in Example 1, except that an 80 μm poly (methyl) methacrylate (PMMA) film was used as the protective film.

Example 5

A window-polarizing plate laminate was manufactured through the same process as described in Example 1, except that a 50 µm cycloolefin-based (COP) film was used as the protective film.

Comparative Example 1

In Example 1 (2), the window-polarizing plate laminate was manufactured by the same process as described in Example 1, except that the hard coating layer was formed to have a thickness of 20 μm after curing.

Comparative Example 2

15 parts by weight of a 6-functional acrylate (PU620D, Miwon Specialty Chemical) as a photocurable resin and 30 parts by weight of propylene glycol monomethyl ether dispersed 15 nm reactive silica sol (40% solids), 1-hydroxycyclohexyl-phenyl- as a photoinitiator 2.7 parts by weight of ketone, 52 parts by weight of propylene glycol monomethyl ether as a solvent, and 0.3 parts by weight of BYK-UV3570 (BYK) as a leveling agent were mixed in a stirrer and filtered using a PP filter to prepare a hard coating composition. .

Using the hard coating composition, a window-polarizing plate laminate was prepared through the same process as described in (2) and (3) of Example 1.

Comparative Example 3

15 parts by weight of pentaerythritol triacrylate as photocurable resin and 30 parts by weight of propylene glycol monomethyl ether dispersed 15 nm reactive silica sol (40% solids), 2.7 parts by weight of 1-hydroxycyclohexyl-phenyl-ketone as a photoinitiator, solvent 52 parts by weight of propylene glycol monomethyl ether and 0.3 parts by weight of BYK-UV3570 (BYK) as a leveling agent were mixed in a stirrer and filtered using a PP filter to prepare a hard coating composition.

Using the hard coating composition, a window-polarizing plate laminate was prepared through the same process as described in (2) and (3) of Example 1.

Experimental Example

A touch sensor layer comprising an ITO pattern of 45 nm as an electrode on a polarizer of the window-polarizing plate laminate manufactured according to Examples 1 to 5 and Comparative Examples 1 to 3, and a silicon oxide insulating layer covering the electrode. Was transferred to prepare an optical laminate.

After preparing a specimen having a length of 50 mm × width of 5 mm using the optical laminated body, crystal toughness was measured using an SHIMAZHU AUTOGRAPH AG-X 1KN instrument. Specifically, by pulling the specimen at a constant tensile speed of 4mm / min in the longitudinal direction, by measuring the stress according to the strain until failure, it is possible to obtain the stress and strain at the break point. Thereafter, the modified toughness of Equation 1 was calculated through, for example, a stress-strain curve as shown in FIG. 18.

Flexibility evaluation was performed about the optical laminated bodies of the said Example and the comparative example as follows, and the evaluation result is shown in Table 1.

Flexibility evaluation

A rod having a diameter of 3 mm was placed on the center of the width of the optical laminates of Examples and Comparative Examples (on the side of the hard coating layer), and repeatedly folded until the two edges of the optical laminate reached in the longitudinal direction, and then returned to the original state. The number of times before the film broke was evaluated. Evaluation criteria are as follows.

S: No breakage up to 200,000 times

A: Breakage occurred more than 100,000 times and less than 200,000 times

B: Fracture occurred at 50,000 times or more but less than 100,000 times

C: Failure occurs less than 50,000 times

division Break point stress
(Mpa) Break Point Strain
(%) Fertility
(MPa%) Flexibility Assessment Results Example 1 66.1 7.2 475.9 S Example 2 65.3 6.3 411.4 S Example 3 64.9 6.0 389.4 A Example 4 61.2 5.5 336.6 A Example 5 59.8 5.3 316.9 A Comparative Example 1 56.4 5.2 293.3 B Comparative Example 2 55.5 4.8 266.4 C Comparative Example 3 53.8 4.5 242.1 C

Referring to Table 1, in the embodiments, when the modified toughness of the optical laminate exceeds about 300 Mpa%, improved flexibility is secured without substantially breaking, and when it exceeds about 400 Mpa%, more flexibility is achieved. This was implemented.

In the comparative examples, the fracture phenomena increased as the modified toughness dropped to less than about 300 Mpa%, and as the modified toughness was further reduced, the flexibility property was further deteriorated.

100: window 102: optical substrate
104: hard coating layer 104a: functional layer
107: Light shielding pattern 110: Polarizing layer
110a: liquid crystal layer 110b: alignment layer
112: first protective film 114: stretched polarizer
116: second protective film 120: adhesive layer
120a: first adhesive layer 120b: second adhesive layer
130: touch sensor layer 200: substrate
205: separation layer 210: intermediate layer
220: electrode 220a: first electrode
220b: second electrode 230: insulating layer
240: protective film

Claims (19)

A window having a modified toughness of at least 10,000 Mpa%; And
A polarizing layer disposed on one surface of the window,
Wherein the modified toughness represents the product of stress (Mpa) and strain (%) at the breakpoint of the stress-strain curve. The optical laminate of claim 1, wherein the Martens hardness of the window is at least 200 N / mm ² at a 10 mN load. The optical laminate of claim 1, wherein the window satisfies Equation 2:
[Equation 2]
(Friction coefficient / water contact angle) * 1,000 ≤2.5 / degree ( ^o ). The optical laminate of claim 1, wherein the window has a thickness of 40 to 150 μm. The optical laminated body of Claim 1 whose crystal toughness of the whole optical laminated body is 300 MPa% or more. The optical laminated body of Claim 1 whose thickness of the said polarizing layer is 5-100 micrometers. The optical laminated body of Claim 1 whose polarization degree of the said polarizing layer is 95% or more, and light transmittance is 42% or more. The optical laminate according to claim 1, wherein the polarizing layer includes an elongated polarizer, and the contracting force of the polarizing layer is 1.5 N or less. The optical laminate of claim 1, further comprising a touch sensor layer disposed on the polarizing layer or between the window and the polarizing layer. The optical laminate according to claim 9, wherein the polarizing layer and the touch sensor layer are sequentially stacked from the one surface of the window. A window having a modified toughness of at least 10,000 Mpa%; And
A touch sensor layer disposed on one surface of the window;
Wherein the modified toughness represents the product of stress (Mpa) and strain (%) at the breakpoint of the stress-strain curve. The optical laminate of claim 11, wherein the Martens hardness of the window is at least 200 N / mm ² at a 10 mN load. The optical laminate of claim 11, wherein the window satisfies Equation 2:
[Equation 2]
(Friction coefficient / water contact angle) * 1,000 ≤2.5 / degree ( ^o ). The optical laminate of claim 11, wherein the window has a thickness of 40 to 150 μm. The optical laminated body of Claim 11 whose crystal toughness of the whole optical laminated body is 300 MPa% or more. The optical laminate according to claim 11, wherein the touch sensor layer has a thickness of 1 to 100 µm. The optical laminate according to claim 11, wherein the light transmittance of the touch sensor layer is 85% or more, and the touch sensor layer includes an electrode having a refractive index of 1.3 to 2.5. The optical laminate of claim 11, further comprising a polarizing layer disposed on the touch sensor layer or between the window and the touch sensor layer. The optical laminate according to claim 18, wherein the polarizing layer and the touch sensor layer are sequentially stacked from the one surface of the window.

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