JP2017042989A - Optical laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical laminate that can contribute to an improvement in impact resistance and a reduction in the weight of a display device.SOLUTION: The optical laminate is provided with a thin glass having a thickness of 100 μm or less, and a conductive film disposed on one side of the thin glass. The conductive film contains a substrate and a conductive layer that is disposed on one side of the substrate. In one embodiment of the invention, the optical laminate is further provided with an adhesive layer between the thin glass and the conductive film.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical laminate. More specifically, the present invention relates to an optical laminate including a conductive film.

  In recent years, information terminals such as smartphones and tablet PCs are widely used. In many cases, a protective material for protecting the display device is disposed on the outermost surface side of these devices. The display devices provided in the above-mentioned devices that are often carried around or operated by hand are increasingly required to reduce weight and improve impact resistance, and a protective material capable of meeting the requirements is required. . Further, from the viewpoint of reducing the weight of the entire display device, a thin protective material having both a protective function and other functions is required.

  As the protective material, a glass plate or a plastic plate is used (for example, Patent Document 1). As the glass plate, tempered glass having higher strength than normal glass is used. Although glass plates are excellent in impact resistance and hardness, there is a problem that the specific gravity is high and heavy. In addition, when the glass material is made thin for weight reduction, there is a problem that impact resistance is remarkably lowered. For the plastic plate, a material having excellent transparency such as polymethyl methacrylate and polycarbonate can be used. Although a plastic plate is lighter than a glass plate, when a plastic plate is used, it is difficult to achieve both impact resistance and hardness required as a protective material.

JP 2010-164938

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide an optical laminate that can contribute to weight reduction of the display device and improvement in impact resistance.

The optical laminate of the present invention comprises a thin glass having a thickness of 100 μm or less and a conductive film disposed on one side of the thin glass, the conductive film comprising a base material and one side of the base material And a conductive layer.
In one embodiment, the optical layered body of the present invention further includes an adhesive layer between the thin glass and the conductive film.
In one embodiment, the adhesive layer includes an epoxy resin.
In one embodiment, the elastic modulus at 23 ° C. of the base material is 1.5 GPa to 10 GPa.
In one embodiment, the optical layered body of the present invention further includes an antireflection layer, and the antireflection layer is disposed on the opposite side of the thin glass from the conductive film.

  ADVANTAGE OF THE INVENTION According to this invention, it is an optical laminated body which has an electroconductive film, Comprising: The optical laminated body excellent in lightweight, high hardness, and impact resistance can be provided. The optical layered body of the present invention can be suitably used as a front plate of a display device, and can contribute to weight reduction of the display device and improvement in impact resistance while exhibiting conductivity. Moreover, since the optical laminated body of this invention is excellent in flexibility, it can be provided with the form of a roll and is excellent also in handleability.

It is a schematic sectional drawing of the optical laminated body by one Embodiment of this invention.

A. Overall configuration diagram 1 of the optical stack is a schematic sectional view of an optical laminate according to one embodiment of the present invention. The optical laminated body 100 includes a thin glass 10 having a thickness of 100 μm or less and a conductive film 20 disposed on one side of the thin glass 10. The conductive film 20 includes a base material 21 and a conductive layer 22 formed on one side of the base material 21. Preferably, the thin glass 10 and the conductive film 20 are laminated via the adhesive layer 30. In one embodiment, the conductive layer 22 and the thin glass 10 are laminated via the adhesive layer 30 as in the illustrated example. In another embodiment, the substrate and the thin glass are laminated via an adhesive layer.

  Since the optical layered body of the present invention includes thin glass, the hardness is high. Moreover, the optical layered body of the present invention is provided with a conductive film on one side of the thin glass, whereby breakage of the thin glass can be prevented and the impact resistance is excellent. In the present invention, the impact applied to the surface of the thin glass (the surface opposite to the conductive film) can be effectively released to the conductive film side, so that it is considered to have excellent impact resistance as described above. . Such an effect becomes prominent when the conductive film has a base material or when thin glass and a conductive film are laminated via an adhesive layer. Furthermore, since the thin glass is difficult to break, the thickness of the thin glass can be made very thin, and as a result, a lightweight optical laminate can be obtained. As described above, the optical laminate having excellent impact resistance, light weight, and high hardness can be suitably used as a front plate of an image display device for mobile use. In addition, when using the optical laminated body of this invention as a front plate, it is preferable to arrange | position with the thin glass side being the outside (namely, visual recognition side).

  Further, the thin glass has a function of protecting the conductive layer or the substrate of the conductive film, and can impart, for example, scratch resistance to these members. That is, in the present invention, the thin glass and the conductive film protect each other. Therefore, it is possible to reduce the number of protective members, and a lightweight and thin optical laminate can be obtained. Moreover, thin glass has high gas barrier properties, and the optical laminate of the present invention configured such that the thin glass protects the conductive film can also function as a gas barrier film.

  The thickness of the optical layered body of the present invention is preferably 1 μm to 300 μm, more preferably 10 μm to 200 μm, and more preferably 20 μm to 150 μm.

  The optical layered body of the present invention may further include other layers. Examples of other layers include an antireflection layer, an antiglare layer, an antistatic layer, and an optical functional layer. A decorative layer may be partially provided between the conductive film and the glass. The decorative layer plays the role of blindfold when a metal wiring or the like is provided on the outer frame of the conductive film. A film provided with a decorative layer may be laminated between the thin glass and the conductive film. Moreover, you may provide arbitrary appropriate adhesive layers in the surface on the opposite side to the thin glass of the said conductive film. In an optical layered product provided with an adhesive layer, a separator may be arranged on the surface of the adhesive layer. The separator can protect the pressure-sensitive adhesive layer until the optical laminate is put into practical use.

  In one embodiment, the optical laminate of the present invention is provided in roll form. It is one of the achievements of the present invention to provide an optical layered body that has high hardness and is flexible enough to be wound into a roll.

B. Thin glass As long as the said thin glass is a plate-shaped thing, arbitrary appropriate things may be employ | adopted. Examples of the thin glass include soda-lime glass, borate glass, aluminosilicate glass, and quartz glass according to the classification according to the composition. Moreover, according to the classification | category by an alkali component, an alkali free glass and a low alkali glass are mentioned. The content of alkali metal components (for example, Na ₂ O, K ₂ O, Li ₂ O) in the glass is preferably 15% by weight or less, and more preferably 10% by weight or less.

  The thin glass has a thickness of 100 μm or less, preferably 80 μm or less, more preferably 50 μm or less, still more preferably 40 μm or less, and particularly preferably 35 μm or less. The minimum of the thickness of the said thin glass becomes like this. Preferably it is 5 micrometers or more, More preferably, it is 20 micrometers or more.

  The light transmittance of the thin glass at a wavelength of 550 nm is preferably 85% or more. The refractive index of the thin glass at a wavelength of 550 nm is preferably 1.4 to 1.65.

The density of the thin glass is preferably ^{2.3g / cm 3 ~3.0g / cm 3} , more preferably from ^{2.3g / cm 3 ~2.7g / cm 3} . If it is thin glass of the said range, a lightweight optical laminated body will be obtained.

  Arbitrary appropriate methods may be employ | adopted for the shaping | molding method of the said thin glass. Typically, the above thin glass is a mixture of a main raw material such as silica or alumina, an antifoaming agent such as sodium nitrate or antimony oxide, and a reducing agent such as carbon at a temperature of 1400 ° C to 1600 ° C. Then, after forming into a thin plate shape, it is produced by cooling. Examples of the method for forming the thin glass include a slot down draw method, a fusion method, and a float method. The thin glass formed into a plate shape by these methods may be chemically polished with a solvent such as hydrofluoric acid, if necessary, in order to reduce the thickness or improve the smoothness.

  As the thin glass, a commercially available one may be used as it is, or a commercially available thin glass may be polished to have a desired thickness. Examples of commercially available thin glass include “7059”, “1737” or “EAGLE 2000” manufactured by Corning, “AN100” manufactured by Asahi Glass, “NA-35” manufactured by NH Techno Glass, and “OA-” manufactured by Nippon Electric Glass. 10 ”,“ D263 ”or“ AF45 ”manufactured by Schott Corporation.

C. Conductive film The conductive film can be formed on any suitable base material by any suitable film formation method (for example, vacuum deposition method, sputtering method, CVD method, ion plating method, spray method, etc.). It can be formed by forming an oxide film.

  Examples of the metal oxide include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Of these, indium-tin composite oxide (ITO) is preferable.

  The thickness of the conductive layer is preferably 100 nm or less, more preferably 50 nm or less, and further preferably 35 nm or less. The lower limit of the thickness of the conductive layer is preferably 10 nm.

  The base material is composed of any appropriate resin. As resin which comprises the said base material, the curable resin etc. which harden | cure with a thermoplastic resin and a heat | fever or an active energy ray etc. are mentioned, for example. A thermoplastic resin is preferable. Specific examples of thermoplastic resins include poly (meth) acrylate resins, polycarbonate resins, polyethylene resins, polypropylene resins, polystyrene resins, polyamide resins, polyethylene terephthalate resins, polyarylate resins, polyimide resins. , Polysulfone resins, cycloolefin resins and the like. Of these, poly (meth) acrylate resins are preferred, polymethacrylate resins are more preferred, and polymethyl methacrylate resins are particularly preferred. If the resin film contains a polymethyl methacrylate resin, the effect of protecting the thin glass is enhanced.

  The elastic modulus at 23 ° C. of the base material is preferably 1.5 GPa to 10 GPa, more preferably 1.8 GPa to 9 GPa. If it is such a range, the conductive film which can protect the said thin glass effectively can be obtained. The elastic modulus in the present invention can be measured by dynamic viscoelastic spectrum measurement.

Fracture toughness value at 25 ° C. of the substrate ^{is 1.5MPa · m 1/2 ~10MPa · m 1/2} , and preferably from ^{2MPa · m 1/2 ~6MPa · m 1/2} , more preferably is a ^{2MPa · m 1/2 ~5MPa · m 1/2} . If the fracture toughness value of the substrate is within such a range, the protective film has sufficient tenacity, so that the thin glass is reinforced to prevent the cracks and breakage of the thin glass and to have excellent flexibility. An optical laminate can be obtained.

The linear expansion coefficient of the base material is preferably greater than 0 / ° C., more preferably 1.0 × 10 ⁻⁶ / ° C. to 10 × 10 ⁻⁶ / ° C., and even more preferably 4.0 × 10 ^−6. / ° C. to 50 × 10 ⁻⁶ / ° C. In addition, a linear expansion coefficient is calculated | required according to JISK7197.

  The thickness of the substrate is preferably 10 μm to 500 μm, and more preferably 50 μm to 250 μm.

  The conductive layer can be patterned by an etching method, printing, or the like. By conducting the patterning, a conductive portion and an insulating portion can be formed. As a patterning method for such patterning, any appropriate method can be adopted as long as the effects of the present invention are not impaired. Examples of such a patterning method include a wet etching method and a screen printing method.

  Any appropriate method can be adopted as the wet etching method. Specific operations of the wet etching method include, for example, operations described in US2011 / 0253668A. This publication is incorporated herein by reference.

  The mask used in the wet etching method can be formed in any appropriate shape depending on a desired conductive pattern. After the etching process, a region where the mask is formed becomes a conductive portion, and a region where the mask is not formed becomes an insulating portion. The mask is made of, for example, a photosensitive resin. Examples of a method for forming the mask include a screen printing method.

  After the mask is formed, for example, the conductive film is immersed in an etchant and an etching process is performed. Specific examples of the etching solution include nitric acid, phosphoric acid, acetic acid, hydrochloric acid, and a mixed solution thereof. After the etching process, the mask is removed by a conventional method.

  In the screen printing method, for example, according to a desired conductive pattern, a conductive part forming material is selectively applied to form a conductive part. On the other hand, the insulating part is formed by applying an insulating part forming material to a region other than the conductive part. In this embodiment, the conducting part and the insulating part may include a resin matrix made of the same resin, or may contain a resin matrix made of different resins.

D. Other layers D-1. Resin Film The optical laminate of the present invention may further comprise a resin film on the side opposite to the thin glass conductive film. In one embodiment, the resin film is releasably laminated (eg, via any suitable adhesive layer) to protect the thin glass until the optical laminate of the present invention is ready for use.

  Arbitrary appropriate resin may be employ | adopted for the material which comprises the said resin film. Examples of the resin include thermoplastic resins and curable resins that are cured by heat or active energy rays. A thermoplastic resin is preferable. Specific examples of thermoplastic resins include poly (meth) acrylate resins, polycarbonate resins, polyethylene resins, polypropylene resins, polystyrene resins, polyamide resins, polyethylene terephthalate resins, polyarylate resins, polyimide resins. , Polysulfone resins, cycloolefin resins and the like. Of these, poly (meth) acrylate resins are preferred, polymethacrylate resins are more preferred, and polymethyl methacrylate resins are particularly preferred. If the resin film contains a polymethylmethacrylate resin, the effect of protecting the thin glass is enhanced. For example, it is possible to prevent the occurrence of scratches, holes, etc. even on a falling object with a sharp tip.

  The thickness of the resin film is preferably 20 μm to 1900 μm, more preferably 50 μm to 1500 μm, more preferably 50 μm to 1000 μm, and particularly preferably 50 μm to 100 μm.

The specific gravity of the resin film ^{is 0.9g / cm 3 ~1.5g / cm 3} , preferably from ^{1g / cm 3 ~1.3g / cm 3} .

  The resin film may further contain any appropriate additive depending on the purpose. Examples of additives in the resin film include diluents, anti-aging agents, denaturing agents, surfactants, dyes, pigments, anti-discoloring agents, ultraviolet absorbers, softeners, stabilizers, plasticizers, antifoaming agents, A reinforcing agent etc. are mentioned. The kind, number, and amount of additives contained in the resin film can be appropriately set according to the purpose.

D-2. Antireflection layer The optical layered body of the present invention may further include an antireflection layer. The antireflection layer may be disposed on the side opposite to the thin glass conductive film.

  The antireflection layer may have any appropriate configuration as long as it has an antireflection function. Preferably, the antireflection layer is a layer composed of an inorganic material.

  Examples of the material constituting the antireflection layer include titanium oxide, zirconium oxide, silicon oxide, and magnesium fluoride. In one embodiment, a laminate obtained by alternately laminating titanium oxide layers and silicon oxide layers is used as the antireflection layer. Such a laminate has an excellent antireflection function.

D-3. Adhesive layer The thin glass and the conductive film may be laminated via an adhesive layer. Examples of the material constituting the adhesive layer include a thermosetting resin and an active energy ray curable resin. Specific examples of such a resin include, for example, epoxy resins; cyclic ethers having an epoxy group, a glycidyl group, or an oxetanyl group; silicone resins; acrylic resins and mixtures thereof. Among these, preferably, an adhesive layer containing an epoxy resin can be formed. If an adhesive layer containing an epoxy resin is formed, it is possible to obtain an optical laminate that is less likely to break thin glass and that is superior in impact resistance. Moreover, you may add the said coupling agent to the said contact bonding layer.

  The thickness of the adhesive layer is preferably 10 μm or less, and more preferably 0.05 μm to 50 μm. If it is such a range, an optical laminated body which is hard to be damaged and excellent in impact resistance can be obtained.

E. The manufacturing method of the optical stack of the production method the present invention of the optical stack, any appropriate method may be employed. The manufacturing method includes, for example, (1) a bonding step of bonding a thin glass and a conductive film on one surface of a thin glass via an adhesive composition, and (2) curing the adhesive composition, A curing step of forming an adhesive layer.

  As described above, the pressure-sensitive adhesive composition preferably contains a thermosetting or photocurable adhesive. A thermosetting adhesive and a photocurable adhesive may be used in combination. As the adhesive, an adhesive containing the resin described in the section D-3 can be used.

  The adhesive composition may further contain any appropriate additive depending on the purpose. Examples of the additive in the adhesive composition include a polymerization initiator, a crosslinking agent, a UV absorber, a conductive material, and a Si coupling agent.

  The thin glass and the conductive film are bonded to each other by any appropriate means. Typically, laminating is performed. In the optical layered body of the present invention, the thin glass and the conductive film may be bonded continuously by so-called roll-to-roll. The roll-to-roll refers to a method in which long films (thin glass and resin film in the present invention) are roll-conveyed and bonded together with their longitudinal directions aligned.

The method for curing the adhesive composition can be appropriately selected according to the type of the adhesive. When the adhesive is a photocurable adhesive, the adhesive composition can be cured by ultraviolet irradiation. Irradiation conditions can be appropriately selected according to the type of adhesive, the composition of the adhesive composition, and the like. Irradiation integrated light quantity for curing the applied adhesive composition is, for ^{example, 100mJ / cm 2 ~2000mJ / cm 2} . When the adhesive is a thermosetting adhesive, the adhesive composition is cured by heating. The heating conditions can be appropriately selected according to the type of adhesive, the composition of the adhesive composition, and the like. The heating conditions for curing the applied adhesive composition are, for example, a temperature of 100 ° C. to 200 ° C. and a heating time of 5 minutes to 30 minutes.

  When the optical layered body of the present invention includes the antireflection layer, the antireflection layer is formed by any appropriate method. For example, the antireflection layer is formed on the thin glass by using a method such as vacuum deposition, sputtering, or ion plating. Further, the antireflection layer may be formed by transferring a film having an antireflection function using the resin film described in the section E-1.

DESCRIPTION OF SYMBOLS 10 Thin glass 20 Conductive film 21 Base material 22 Conductive layer 30 Adhesive layer 100 Optical laminated body

Claims (5)

A thin glass having a thickness of 100 μm or less, and a conductive film disposed on one side of the thin glass,
The conductive film includes a base material and a conductive layer disposed on one side of the base material.
Optical laminate.   The optical laminate according to claim 1, further comprising an adhesive layer between the thin glass and the conductive film.   The optical laminated body according to claim 2, wherein the adhesive layer contains an epoxy resin.   The optical laminated body in any one of Claim 1 to 3 whose elasticity modulus in 23 degreeC of the said base material is 1.5GPa-10GPa. 5. The optical laminate according to claim 1, further comprising an antireflection layer, wherein the antireflection layer is disposed on the side of the thin glass opposite to the conductive film.

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