JP2007256580A - Laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated film having a transparent electrode layer which has sufficient wear resistance so as not to be broken during electrode wiping-off work even if the conventional method of forming a conductive protective layer on the transparent electrode layer using a conductive paste is not employed, and to provide an information display member having an image display layer and a cover film laminated on the laminated film. <P>SOLUTION: The laminated film has an SiO<SB>x</SB>film formed as an underlayer on a transparent base material film and has the transparent electrode layer having conductive oxide layers and metallic layers repeatedly laminated on the underlayer is used, and at least the image display layer and the cover film are laminated on the laminated film in this order. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laminated film used for an information display member used for a time display board of a train or bus or a bulletin board on a street as a display member for electronic books and a large information bulletin board, and a manufacturing method thereof.

  As one of display devices using the electrophoresis phenomenon, a microcapsule electrophoresis system has been put into practical use. In this type of display device, positively and negatively charged white particles and black particles are placed in a microcapsule filled with a transparent solvent, and an image is formed by pulling up each particle to the display surface by applying an external voltage. It is. The particle size of the microcapsule is several tens μm to several hundred μm, and when the microcapsule is dispersed in a transparent binder, it can be coated like an ink.

  When this capsule is coated on a transparent base material on which a transparent electrode is formed and the base material on which an active matrix driving electrode circuit is formed is bonded, for example, an active matrix electrophoretic display device as shown in Patent Document 1 is obtained. Can do.

  Here, a transparent electrode is formed on a transparent substrate, and a component coated with a capsule on the transparent electrode is referred to as a “front plate”, and an active matrix driving electrode circuit or the like that is joined to the front plate is formed. The material is called “back plate”.

  Various defects occur in the front plate. Above all, the display defect cannot be confirmed in the state where no voltage is applied, unlike the coating failure in the coating of the microcapsule dispersion. Display defects can be confirmed by applying a voltage to the display material and displaying the microcapsules in white display, black display, and gradation display if necessary. When the display defect inspection is performed after the front plate and the rear plate are joined, a loss of having to dispose of an expensive normal product of the rear plate due to a defect in the front plate occurs. Therefore, it is desirable to perform a display defect inspection at the component stage as the front plate.

  However, the front plate has only one electrode for applying a voltage to the microcapsule. Thus, for example, it has been proposed to use a cover film made of a base material having an inspection electrode deposited with aluminum, and to bond the cover film and the front plate together with an adhesive. By bonding with a cover film having an inspection electrode, it becomes possible to apply a voltage between the transparent electrode and the inspection electrode to drive the microcapsules, so that a display defect inspection of the front plate can be performed.

In order to inspect the display defects of microcapsules, it is necessary to apply a voltage between the transparent electrode and the inspection electrode, and the transparent electrode on the base film and the inspection electrode on the cover film must be exposed and conductive. . Therefore, it is necessary to expose the transparent electrode and the inspection electrode and form an extraction electrode. In order to expose the transparent electrode from the cover film side, it is necessary to remove the microcapsule layer, the adhesive layer, and the cover film. At this time, the thickness of the microcapsule layer is several tens of μm, and the thickness of the adhesive layer is several tens of micrometers. The thickness of μm and the cover film is about several tens μm to several hundreds μm.

As a method for forming the extraction electrode on the transparent electrode side, there is a method of irradiating the entire surface of the extraction electrode with a laser processing apparatus and incinerating and exposing the upper layer of the transparent electrode. Even if irradiated, not only the upper layer such as the microcapsule layer but also the transparent electrode itself is destroyed. Therefore, it is necessary to take out only the cover film by using a processing means such as a laser or a cutter, cut it into the shape of an electrode, and remove the microcapsule layer and the adhesive layer by wiping with a waste cloth, a cotton swab or the like.

  Here, wiping off unnecessary microcapsule layers and adhesive layers on the extraction electrode is simply referred to as “electrode wiping”. When the electrode is wiped off, it is wiped off with a waste cloth or a cotton swab. At this time, there is a problem that the transparent electrode layer is destroyed and wiped together with the microcapsule or the adhesive. When the transparent electrode layer is destroyed by wiping, it becomes a defective product and the yield of good products is reduced.

  Therefore, as a method for solving this problem, Patent Document 2 discloses a method of providing a conductive protective layer having conductivity on the transparent electrode on the electrode extraction portion. In Patent Document 2, a conductive paste in which a conductive filler is dispersed in the presence of an organic solvent in a polyester resin having excellent flexibility as a binder is used as a conductive protective layer by a screen printing method or the like. Is formed. With this method, when removing unnecessary parts with a laser, even if a relatively powerful laser is used, the transparent electrode is protected by the conductive protective layer, so the extraction electrode can be easily formed in a short time. Became possible. However, an electrode wiping operation for removing unnecessary portions of the microcapsules and the adhesive in the extraction electrode portion was necessary.

JP 2000-221546 A JP 2004-086192 A

  When the conductive protective layer is formed on the electrode layer by screen printing using a conductive paste, the formed conductive protective layer has a thickness of about 3 to 10 μm, and when the image display layer is applied in the next step There is a problem that the display layer cannot be coated around the protective layer, that is, a so-called coating omission defect occurs.

  Furthermore, when the base film is wound into a roll shape, the conductive protective layer is thick, so that the winding is displaced and the base film is deformed. As a result, there is a problem that cracks occur in the conductive protective layer and electrical conductivity deteriorates.

  In addition, when a conductive paste is used, it is necessary to provide a drying step in order to remove the organic solvent in the paste. By passing the web-shaped substrate through a high-temperature drying furnace, the web-shaped substrate film is struck, and when coating the image display layer, uneven coating defects occur, or when cutting with a laser or the like. However, there was a problem that processing accuracy was reduced and defective products were frequently generated. In addition, ITO and IZO used for the electrode layer have a problem that the crystal structure varies due to the heat of the drying furnace, and the water vapor barrier property of the web-like substrate film is lowered.

  Furthermore, when the conductive protective layer is formed by the printing method, another manufacturing process increases, and accordingly, material costs and labor costs increase, and further, the product yield decreases due to an increase in work processes. .

  The present invention solves the problems of the prior art, and it is destroyed by the electrode wiping operation without forming a conductive protective layer on the transparent electrode layer using the conductive paste which is a conventional method. An object of the present invention is to provide a laminated film provided with a transparent electrode layer having sufficient wear resistance and an information display member in which an image display layer and a cover film are laminated on the laminated film.

  In order to solve the above problems, the invention according to claim 1 is a laminated film characterized in that a transparent electrode layer in which a conductive oxide layer and a metal layer are repeatedly laminated is provided on a transparent substrate film.

  The invention according to claim 2 is a laminated film characterized in that the metal layer has a thickness of 5 nm to 20 nm.

  In the invention according to claim 3, the transparent base film has a base layer made of SiOx, and a transparent electrode layer in which a conductive oxide layer and a metal layer are repeatedly laminated is provided on the base layer. A laminated film according to claim 1 or claim 2 characterized in that.

  An invention according to claim 4 is an information display member characterized in that at least an image display layer and a cover film are sequentially laminated above the transparent electrode layer of the laminated film according to any one of claims 1 to 3. did.

  According to a fifth aspect of the present invention, there is provided the information display member for an electrophoretic display device according to the fourth aspect, wherein the image display layer is a microcapsule electrophoretic image display layer.

  In the present invention, the transparent electrode layer has a laminated structure of a transparent oxide layer and a metal layer, so that the transparent electrode layer has high peel strength and wear resistance compared to the case of a transparent oxide layer single layer. It was able to be set as the laminated film excellent in.

  Moreover, it became possible to maintain the transparency of a transparent electrode layer, having sufficient abrasion resistance by making the film thickness of a metal layer into 5 nm or more and 20 nm or less.

  Further, by providing the transparent electrode layer on the base layer, the adhesive strength between the transparent electrode layer and the substrate sheet is improved, and the wear resistance can be further improved.

  Even when an image display layer, a cover film, and the like are formed on the laminated film and an extraction electrode is formed by wiping the electrode, the transparent electrode can be efficiently manufactured without breaking the transparent electrode.

  In addition, by making the image display layer a microcapsule type electrophoretic display layer, the microcapsules can be dispersed in a binder to enable coating like an ink, and an information display member can be manufactured at low cost. It became possible to manufacture.

  Hereinafter, embodiments of the present invention will be described. FIG. 1 shows an explanatory sectional view of the laminated film of the present invention. In FIG. 1, a laminated film has a base layer 2 and a transparent electrode layer 3 on a transparent substrate film 1, and the transparent electrode layer is a laminated film in which a conductive oxide layer 31 and a metal layer 32 are repeatedly laminated. .

  In the laminated film of the present invention, the transparent electrode layer has a laminated structure in which the conductive oxide layer 31 and the metal layer 32 are repeatedly laminated. In FIG. 1, the transparent electrode layer has a five-layer structure of conductive oxide layer 31 / metal layer 32 / conductive oxide layer 31 / metal layer 32 / conductive oxide layer 31, but the transparent electrode layer of the present invention is It suffices to have a structure in which at least two conductive oxide layers are provided and a metal layer is sandwiched between the conductive oxide layers. Further, the uppermost layer or the lowermost layer of the transparent electrode layer 3 may be a metal layer.

  Examples of the transparent substrate film of the present invention include biaxially stretched polyethylene terephthalate (PET), stretched polyethylene (OPE), biaxially stretched polypropylene (OPP), stretched nylon (ONy), and ionomer (IO) having a thickness of about 20 μm. A biaxially stretched polyethylene terephthalate film can be suitably used from the viewpoints of various strengths and ease of handling. Moreover, the base layer 2 and the transparent electrode layer 3 can be laminated | stacked by a roll-to-roll system by making a transparent base film into a web form.

The material for forming the conductive oxide layer 31 used in the transparent electrode layer 3 of the present invention can be appropriately selected and used as long as it is normally used when forming a transparent conductive film. An oxide (ITO), antimony / tin oxide (ATO), indium / zinc oxide (IZO), tin oxide (SnO ₂ ), calcium tungstate (CaWO ₄ ), or the like can be used. These materials can be deposited by a dry deposition method to form a conductive oxide layer on a substrate. As the dry film forming method, a sputtering deposition method, an ion plating method, a vacuum deposition method, a laser deposition method, an ion beam deposition method, or the like can be used.

  The material for forming the metal layer 32 used in the transparent electrode layer of the present invention may be any known metal, but silver (Ag), nickel (Ni), zinc (Zn), indium (In), copper A material selected from (Cu) and lead (Pb) can be suitably used. A film can be formed by a dry film forming method to form a metal layer on the substrate. As the dry film forming method, a sputtering deposition method, an ion plating method, a vacuum deposition method, a laser deposition method, an ion beam deposition method, or the like can be used.

  The film thickness of the metal layer in the transparent electrode layer 3 of the present invention is preferably 5 nm or more and 20 nm or less. When the thickness of the metal layer is less than 5 nm, the effect of the present invention, that is, the improvement of the wear resistance of the transparent electrode layer, may not be obtained. Moreover, when the film thickness of a metal layer exceeds 20 nm, transparency will fall.

  The laminated film of the present invention is characterized in that a base layer 2 made of SiOx is provided on a transparent substrate film 1 and a transparent electrode layer 3 is provided on the base layer 2. Compared to the case where the transparent electrode layer 3 is directly laminated on the base film 1, the underlayer can improve the adhesive strength between the base film and the transparent electrode layer, and improve the abrasion resistance of the transparent electrode layer. Can be improved.

  Silicon oxide (SiOx) used for the underlayer 2 can be formed on a substrate by a dry film forming method. Examples of the dry film forming method include a vacuum evaporation method, a sputter evaporation method, an ion plating method, a laser. An evaporation method, an ion beam evaporation method, a CVD method, or the like can be used.

  Next, the information display member of the present invention will be described. FIG. 2 is an explanatory sectional view of the information display member of the present invention. In FIG. 2, the information display member is an image display layer 4, an adhesive layer 5, an inspection electrode layer 6, a cover film on a laminated film 10 in which a base layer 2 and a transparent electrode layer 3 are laminated on a base film 1. 7 is provided.

  As an image display body used for the image display layer, for example, an electroluminescent material, a polymer dispersion type liquid crystal, a strong attraction magnetic liquid crystal, or a microcapsule driven by an electrophoresis method can be used. FIG. 3 shows a schematic cross-sectional view of a microcapsule driven by an electrophoresis method.

  In the microcapsule 12, a dispersion medium 14, white particles 15, and black particles 16 are enclosed in a capsule shell 13. The capsule shell 13 is made of methacrylic acid resin, urea resin, gum arabic, or the like. The dispersion medium is made of a viscous liquid such as silicone oil. The white particles are made of titanium oxide and have a positive charge, the black particles are made of carbon black, and have a negative charge as opposed to the white particles.

  White particles, black particles and a dispersion medium are encapsulated in a capsule shell prepared using a known method such as a phase separation method such as a complex coacervation method, an interfacial polymerization method, an in-situ method, or a solution dispersion cooling method. , Microcapsules. Since the size of the microcapsules is as small as several tens to several hundreds of μm, when the microcapsules are dispersed in a transparent binder, they can be coated like ink.

  The adhesive layer is appropriately provided between the laminate on which the image display layer is formed and the cover film. As the adhesive layer, for example, a pressure-sensitive adhesive (pressure-sensitive adhesive) or a heat-sensitive adhesive can be used in consideration of mounting and the like.

  Examples of the former pressure-sensitive adhesive include a urethane resin pressure-sensitive adhesive composed of a urethane prepolymer obtained by reacting a polyol and a polyisocyanate in the presence of a catalyst such as hexahydrodimethylaniline and a deterioration inhibitor. be able to. As the polyol, polyester polyol, polyether polyol and the like are used, and as the polyisocyanate, aromatic polyisocyanate, aliphatic polyisocyanate, diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate, tolidine diisocyanate, polymethylene polyphenylene polyisocyanate, Tolidine diisocyanate, naphthalene diisocyanate and the like are used. Furthermore, examples of the aliphatic polyisocyanate include hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, and dicyclohexylmethane diisocyanate.

  Examples of the latter heat-sensitive adhesive include linear low density polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene (HDPE), and unstretched polypropylene (CPP) as resins having excellent heat sealability. A polyolefin film having a thickness of about 50 μm can be suitably used.

  However, since these polyolefin resins alone may not be able to balance the adhesive strength and peel strength, for example, these polyolefin resins are further mixed with incompatible components such as polystyrene and polybutene with respect to polyolefin resins. It is also possible to extrude a melt of these mixed resins to form an easily peelable adhesive layer. It is also possible to use a hot melt adhesive made of ethylene-vinyl acetate copolymer resin or the like.

  As the cover film of the information display member according to the present invention, for example, biaxially stretched polyethylene terephthalate (PET), stretched polyethylene (OPE), biaxially stretched polypropylene (OPP), stretched nylon (ONy), ionomer (about 20 μm thick) Although a film such as IO) can be mentioned, a biaxially stretched polyethylene terephthalate film can be suitably used from the viewpoints of various strengths and ease of handling.

  An inspection electrode layer 6 is formed in advance on the cover film 7 of the present invention. As the inspection electrode, a known metal such as aluminum (Al) can be used. Al is formed on the cover film by a vacuum deposition method which is a dry film forming method.

  The information display member uses a web-like base film, is laminated by a roll-to-roll method, and is attached to the cover film. After being bonded to the cover film, the web-shaped information display member is cut or cut using laser light irradiation or a rotary cutter. For example, as the laser beam irradiation means, any laser beam can be used as long as the cut is formed or cut in the information display member that is a laminate. If the base film is a resin film, a carbon dioxide laser is usually used. Depending on the material of the film, a YAG laser, excimer laser, wavelength tunable die laser, or the like can also be used.

  FIG. 4 shows a plane explanatory view and a cross-sectional explanatory view of the information display member of the present invention having an electrode extraction portion. Fig.4 (a) is a plane explanatory view from the cover film side, P becomes an electrode extraction part of a transparent electrode. FIG. 4B is an explanatory plan view from the base film side, and Q is an extraction electrode for the inspection electrode. FIG. 4C is a cross-sectional explanatory view taken along line AA ′ in FIGS. 4A and 4B. In the extraction electrode P of the transparent electrode, the cover film 7, the inspection electrode 6, the adhesive layer 5, and the information display layer 4 are removed from the cover film 7 side, and the transparent electrode 3 is exposed. In the inspection electrode take-out electrode Q, the base film 1, the base layer 2, the transparent electrode layer 3, the information display layer 4, and the adhesive layer 5 are removed from the base film side. Is exposed.

  Moreover, it is preferable that the electrode extraction part of a transparent electrode layer and the electrode layer for a test | inspection shall be 2 places or 2 places or more. By using two or more locations, the response speed of the image display layer can be made uniform in the plane when a voltage is applied to the transparent electrode layer and the inspection electrode layer.

  The extraction electrode is formed by cutting only the base film or the cover film by laser irradiation, so-called laser ablation, and after removing the base film or the cover film, unnecessary portions such as the image display layer are removed by using a waste cloth, a cotton swab, a non-woven fabric, or the like. It is formed by wiping and removing.

  The information display member of the present invention can be driven by peeling the cover film 7 and the inspection electrode 6 and bonding them together with the electrode circuit for driving the active matrix (back plate). FIG. 5 shows a cross-sectional explanatory diagram of a display form in an electrophoretic display device using microcapsules.

  The microcapsule is sandwiched between the transparent electrode layer 2 and the electrode layer 9. When an electric field is applied to the transparent electrode layer 2 and the electrode layer 9, the transparent electrode layer 2 is a negative electrode and the electrode layer 9 is a positive electrode. Since the charged white particles 15 are drawn to the transparent electrode layer 2 side and the black particles 16 are drawn to the electrode layer 9 side, the portion looks white when observed from above the transparent electrode layer 2 side. Conversely, when the transparent electrode layer 2 is the positive electrode and the electrode layer 9 is the negative electrode, the positively charged white particles 15 are drawn to the electrode layer 9 side, and the black particles 16 are the transparent electrode layer 2 side. Therefore, when observed from above the transparent electrode layer 2 side, the portion looks black.

  The image display layer has a large number of such microcapsules, and by controlling the electric field of each address electrode, a desired character or figure can be displayed as white and black pixels.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, you may delete a some component from all the components shown by embodiment. Furthermore, you may combine the component covering different embodiment suitably.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

A laminated film of the present invention was produced according to the following film formation technique. A film in which SiOx was previously formed to a thickness of 10 nm on a PET substrate was used as a transparent substrate film. After pre-evacuating the inside of the sputtering apparatus to 1.0 × 10 ⁻⁵ Torr using a roll-to-roll type sputtering apparatus, H ₂ O was introduced so that the pressure became 22 Pa, and then at a flow rate of 250 sccm. Ar gas was introduced, a 200 kW DC bias was applied to the ITO target during film formation, and an ITO layer was formed on the transparent substrate film. The web speed of the substrate was 4 m / min.

  Next, Ar gas was introduced at a flow rate of 250 sccm, a 200 kW DC bias was applied to the Ni target, and a Ni layer was formed on the transparent substrate film on which the ITO layer was formed. By repeating the above operation, a transparent electrode layer having a laminated structure of five layers of ITO layer / Ni layer / ITO layer / Ni layer / ITO layer is formed on a transparent base film having SiOx as a base layer and laminated. A film was obtained. In the obtained laminated film, the thickness of all three ITO layers was 20 nm, the thickness of both Ni layers was 15 nm, and the total thickness of the five transparent electrode layers was 90 nm.

Using a cotton swab to which 1 cc of isopropyl alcohol (IPA) is attached, the resulting laminated film is rubbed 10 times with a force of 50 N at a distance of 50 mm, and the peel resistance is measured by measuring the surface resistance value of the wiped portion. Was evaluated. The obtained laminated film had a surface resistance value of 700Ω / □, and it was confirmed that the transparent electrode layer was not destroyed even after the wiping operation. Further, the obtained laminated film exhibited a transmittance of 85 to 90% and a water vapor transmission rate of 0.03 g / m ² · day.

  As a comparative example, a laminated film in which only ITO was laminated at 90 nm under the same conditions as in Example 1 and a base layer made of SiOx and a transparent electrode layer made of ITO were provided on a transparent substrate film was prepared. About the obtained laminated | multilayer film, it wiped off similarly to Example 1, and when the surface resistance value after wiping off was measured, a measured value showed infinite and a transparent electrode layer was destroyed and wiped off by wiping off with a cotton swab It was confirmed that it was taken. Therefore, in the laminated film of this invention, it was confirmed that abrasion resistance is improving compared with the case where a transparent electrode layer is a conductive oxide single layer.

FIG. 1 is an explanatory sectional view of a laminated film of the present invention. FIG. 2 is an explanatory sectional view of the information display member of the present invention. FIG. 3 is an explanatory sectional view of a microcapsule driven by an electrophoresis method. FIG. 4 is a plane explanatory view and a cross-sectional explanatory view of the information display member of the present invention having an electrode extraction portion. FIG. 5 is a cross-sectional explanatory view of a display form in an electrophoretic display device using microcapsules.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent base film 2 Underlayer 3 Transparent electrode layer 31 Conductive oxide layer 32 Metal layer 4 Image display layer 5 Adhesive layer 6 Test electrode layer 7 Cover film 10 Laminated film 12 Microcapsule 13 Capsule shell 14 Dispersion medium 15 White Particle 16 Black particle 17 First electrode 18 Second electrode P Transparent electrode layer extraction electrode Q Inspection electrode extraction electrode

Claims (5)

  A laminated film comprising a transparent electrode layer on which a conductive oxide layer and a metal layer are repeatedly laminated on a transparent substrate film.   The film thickness of the said metal layer is 5 nm or more and 20 nm or less, The laminated film characterized by the above-mentioned.   The transparent substrate film has a base layer made of SiOx, and a transparent electrode layer in which a conductive oxide layer and a metal layer are repeatedly laminated is provided on the base layer. A laminated film according to 1.   An information display member, wherein at least an image display layer and a cover film are sequentially laminated above the transparent electrode layer of the laminated film according to claim 1.   The information display member for an electrophoretic display device according to claim 4, wherein the image display layer is a microcapsule-type electrophoretic image display layer.