JP2000043202A - Optical sheet - Google Patents

Abstract

(57) [Summary] [Problem] To perform a specific treatment on a norbornene-based resin film as a base, further provide a specific cured layer thereon, and then provide a transparent electrode on the cured layer. It is an object of the present invention to provide an optical sheet that provides a strong adhesion between a base layer and a cured layer and has good adhesion between the cured layer and the transparent electrode. SOLUTION: A cured layer (2) of an active energy ray-curable epoxy resin containing at least a part of an alicyclic epoxy resin is provided on a treated surface of a norbornene resin film (1) which has been subjected to an electrical surface treatment. And an optical sheet having a layer structure in which a transparent electrode (3) is provided on the cured layer (2). This optical sheet is particularly suitable as a substrate with a transparent electrode for a touch panel or a polymer ferroelectric liquid crystal display.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical sheet useful as an optical substrate with a transparent electrode, such as a touch panel and a polymer ferroelectric liquid crystal display.

[0002]

2. Description of the Related Art Norbornene resin films (amorphous polyolefin films) have high transparency,
Because it has properties such as a small retardation value (small birefringence) and solvent resistance,
It can be expected to be used as an optical sheet.

The use of norbornene resin films for optical applications is described, for example, in “Plastics, 19
July 1987 (Vol. 38, No. 7), pages 41 to 44,
An article entitled "Polyolefin resin-New polymer for optical disks" APO "" concerning amorphous polyolefin has been published.
Monthly Issue (Vol. 14, No. 12) ”on pages 40-51,“ ART
An article entitled "Application of ON to Transparent Conductive Film" is published.

Japanese Patent Application Laid-Open No. 4-361230 discloses a phase plate for a liquid crystal display having, as a birefringent layer, a film formed by stretching and stretching a thermoplastic saturated norbornene resin sheet.

[0005] Japanese Patent Application Laid-Open No. 6-511117 also discloses that
There is disclosed a polarizing film for a liquid crystal display in which a thermoplastic saturated norbornene-based resin sheet is laminated as a protective layer on at least one surface of a polarizing film.

Japanese Patent Application Laid-Open No. Hei 8-244051 discloses an optical sheet comprising a norbornene-based resin film cross-linked by taking internal or external cross-linking means. On this optical sheet, an organic or inorganic gas-permeable layer, a crosslinked resin cured layer, or the like can be provided. The optical sheet includes, for example, an electrode substrate of a liquid crystal cell constituting a liquid crystal display element, a protective plate of a polarizing element film, a protective plate of a retardation element film, an electrode substrate also serving as a polarizing plate, an electrode substrate also serving as a phase plate, and a touch panel. Film with a transparent electrode (including those used not only on a polarizing plate but also below a polarizing plate), electromagnetic wave shielding plate for CRT, backlight, light guide plate, color filter, optical card, optical tape, optical disk There is a description that it is useful for such purposes.

Japanese Unexamined Patent Publication (Kokai) No. 6-340849 discloses an ultraviolet-curable composition comprising an alicyclic acrylate component, an elastomer and a photopolymerization initiator. In particular, it is disclosed that it is used as an ultraviolet curable adhesive for bonding a molded article of a thermoplastic norbornene resin) to an adherend. The adhesion between the thermoplastic resin molded article and the adherend includes adhesion between a lens, a prism and a metal frame, adhesion between an optical disc substrate and a metal hub, and the like. In order to improve the adhesiveness, the surface of the molded product may be subjected to a surface modification treatment (corona discharge treatment, plasma treatment, electron beam irradiation treatment, ultraviolet irradiation treatment, chemical treatment, etc.) or a primer treatment. There is a description.

Further, the following document describes providing a hard coat layer on a norbornene resin film.

[0009] That is, JP-A-7-97468 (Document 1) discloses a molded article having a silicone-based hard coat layer on the surface of a substrate formed of a thermoplastic norbornene-based resin. Examples of molded articles are glass substitutes for window glass and glass doors, eyeglasses, automobile parts (mirrors and the like) and the like. There is also a description that the surface of the substrate can be modified by energy beam irradiation treatment (corona discharge treatment, plasma treatment, electron beam irradiation treatment, ultraviolet irradiation treatment, etc.).

JP-A-8-12787 (Document 2) discloses an ultraviolet-curable composition comprising a polyfunctional monomer having a (meth) acryloyl group, a (meth) acrylate monomer and a photopolymerization initiator. A thermoplastic norbornene-based resin molded product having a hard coat layer obtained by curing a product is shown. The use of the molded article is, for example, an optical use.

[0011]

In the above document 1, a silicone hard coat layer is formed on a thermoplastic norbornene resin base material. In the above document 2, a molded article of a thermoplastic norbornene resin is formed. Although an acrylic hard coat layer is formed on the substrate, there is still room for improvement in the adhesion between the norbornene resin as a base material and these hard coat layers.

Although the above-mentioned documents 1 and 2 do not disclose the formation of a transparent electrode on the hard coat layer, the documents 1 and 2 do not disclose a hard coat layer serving as a base. Is not always satisfactory in terms of the adhesion itself, so even if we consider forming a transparent electrode on such a hard coat layer, the adhesion with the transparent electrode is still not much expected .

Although the present invention has been studied for forming a transparent electrode such as ITO on a norbornene-based resin film for some time, a transparent electrode having an adhesive force is originally formed on a norbornene-based resin film having originally small polarity. It was not easy to do.

Under such a background, the present invention provides a specific treatment to a norbornene-based resin film as a base, further provides a specific cured layer thereon, and then forms a transparent layer on the cured layer. By providing the electrodes, a strong adhesion between the base layer and the cured layer is obtained, and an object is to provide an optical sheet in which the adhesion between the cured layer and the transparent electrode is also good. Things.

[0015]

The optical sheet of the present invention comprises an active energy ray containing at least a part of an alicyclic epoxy resin on the treated surface of a norbornene resin film (1) which has been subjected to an electrical surface treatment. A cured layer of curable epoxy resin (2) is provided, and a transparent electrode is placed on the cured layer (2).
(3) has a layer configuration provided.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

<Norbornene-based resin film (1)> Examples of the norbornene-based resin include ring-opening (co) polymers of norbornene-based monomers, hydrogenated products thereof, addition-type polymers of norbornene-based monomers, and norbornene-based monomers. Olefinic monomers and addition-type copolymers may be mentioned.

Here, the norbornene-based monomer includes
Norbornene, an alkyl or / and alkylidene-substituted norbornene (5-methyl-2-norbornene,
5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 5-ethylidene-2-norbornene, etc.), polar group-substituted products such as halogen, dicyclopentadiene, 2, 3-dihydrodicyclopentadiene, dimethanooctahydronaphthalene or its alkyl- and / or alkylidene-substituted or polar-substituted products such as halogen, adducts of cyclopentadiene with tetrahydroindene, cyclopentadiene 3- to 4-mer, etc. Is raised.

The norbornene resin has a number average molecular weight (measured by a GPC method using a toluene solvent) of, for example, 25,000 to 100,000 in consideration of physical properties and moldability.
About 30,000 to 80,000 is suitable.

Commercially available norbornene resins include "ZEONEX" manufactured by Zeon Corporation, "APO" manufactured by Mitsui Petrochemical Industries, Ltd., and "ARTON" manufactured by Nippon Synthetic Rubber Co., Ltd.

The norbornene resin film (1) can be obtained by melt extrusion. In general, a resin having high transparency has a high retardation value by extrusion molding, but a norbornene-based resin can obtain a resin having an extremely low retardation value even by extrusion molding. Extruded articles are advantageous in terms of manufacturing costs.

The norbornene resin film (1) can be obtained by casting a norbornene resin. At this time, casting may be performed by blending a crosslinking agent, or external crosslinking may be performed by irradiating an ultraviolet ray, an electron beam, or γ-ray after casting. As the solvent,
A solvent that dissolves the norbornene-based resin (a common solvent with the crosslinking agent when a crosslinking agent is used together) may be used.

When any of the molding methods is employed, additives such as a thermal deterioration inhibitor, an antioxidant, an ultraviolet absorber, an antistatic agent and a lubricant can be added as needed at the time of molding. Stretching can also be performed after film formation.

The thickness of the norbornene-based resin film (1) is not particularly limited. However, in the case of a touch panel, the thickness is often about 30 to 300 μm, particularly about 50 to 200 μm. Norbornene resin film
(1) may be a layer formed by casting or melt extrusion on another plastics layer, and in this case, the thickness of the norbornene-based resin film (1) may be much smaller than the above. Norbornene resin film (1)
May be two or more sheets laminated via an adhesive layer, or may be laminated with another plastics layer via an adhesive layer.

<Electrical Surface Treatment> In the present invention, the above-mentioned norbornene-based resin film (1) is subjected to an electric surface treatment. This treatment is based on the norbornene resin film (1)
May be one side or both sides. If the electrical surface treatment is not performed, sufficient adhesion to the cured layer (2) described below cannot be obtained.

The above-mentioned electric surface treatment includes irradiation treatment with short-wavelength ultraviolet rays, corona discharge treatment, plasma treatment, electron beam irradiation treatment, etc., and particularly the first two persons, especially the first short-wavelength ultraviolet irradiation treatment. is important. Here, short-wavelength ultraviolet rays are typically obtained by irradiation with a low-pressure ultraviolet lamp. The peak wavelength of the low-pressure UV lamp is 184.9
nm and 253.7 nm.

<Curing Layer (2)> The treated surface of the norbornene-based resin film (1) which has been subjected to the electrical surface treatment is provided with an active energy ray-curing type (ultraviolet curable type, at least partially containing an alicyclic epoxy resin). A cured layer (2) of an (electron beam curing type) epoxy resin is formed. The proportion of the alicyclic epoxy resin in the cured layer (2) is 10 to 100% by weight, preferably 20 to 100% by weight.
-100% by weight or more, more preferably 25-100% by weight. If the proportion of the alicyclic epoxy resin is too small, the curing rate during irradiation with active energy rays will be slow, or the adhesion of the cured layer (2) will be insufficient.

Here, the active energy ray-curable epoxy resin containing at least a part of the alicyclic epoxy resin includes:
The resin having the following mechanism (a) or (b) is used, and the resin (b) is particularly important. (A) Acrylic acid is added to an epoxy resin and polymerized by a radical mechanism. (B) Curing the epoxy resin by irradiating it with ultraviolet light in the presence of a cationic polymerization initiator, that is, a method using a cationic polymerization mechanism.

Examples of the alicyclic epoxy resin in the case (b) above include an alicyclic diepoxy acetal, an alicyclic diepoxy adipate having a chemical structure as shown in FIG.
Alicyclic diepoxy carboxylate, vinyl cyclohexene dioxide and the like. Commercially available products include “Celoxide 2021” manufactured by Daicel Chemical Industries, Ltd., and “Celoxide 208” manufactured by Daicel Chemical Industries, Ltd.
1 ”, Ciba-Geigy“ CY175 ”, Union Carbide“ ERL4234 ”, Ciba-Geigy“ C ”
Y177 ”, Union Carbide's“ ERL429 ”
9, "CY179" from Ciba-Geigy, "ERL4221" from Union Carbide, and "ERL4206" from Union Carbide.

Examples of other epoxy resins that can be used in combination with the cycloaliphatic epoxy resin include various epoxy resins including aliphatic and aromatic resins.

Examples of the photopolymerization initiator in the case (b) include Bronsted acid (HPF ₆ , HPF
Onium salts (such as aromatic diazonium salts, aromatic sulfonium salts, and aromatic iodonium salts) of SbF ₆ , HBF ₄ , and HAsF ₆ ; iron aromatic compound salts of Bronsted acid; aluminum complexes / photodegradable silicon compounds; And so on. As a commercial product, "A" manufactured by Asahi Denka Co., Ltd.
DEKA OPTOMER SP-150 "," ADE
KA OPTOMER SP-150 ”and the like (the chemical structural formula is“ Polyfile ”, 1998, Vol. 35, N
o. 408, pages 38-39), Union Carbide's “CYRACUR” manufactured by Asahi Denka Co., Ltd.
E "for photopolymerization initiators" UVI-6974 "," UVI-
6990 ”etc. (The chemical structural formula is“ polyfile ”, 19
96, Vol. 33, no. 384, pp. 37-39), "San Aid SI-6" manufactured by Sanshin Chemical Industry Co., Ltd.
0L ”,“ San Aid SI-80L ”,“ San Aid S ”
I-100L "(1998. Vo of" Polyfile ")
l. 35, no. 409, page 28).

The thickness of the cured layer (2) of the active energy ray-curable epoxy resin containing at least a part of the alicyclic epoxy resin is not limited, but is usually about 0.5 to 80 μm, preferably about 1 to 30 μm. There are many.

A method for forming a cured layer (2) of an epoxy resin on the treated surface of the norbornene-based resin film (1) is as follows.
A method is adopted in which a resin liquid of an active energy ray-curable epoxy resin containing at least a part of an alicyclic epoxy resin is coated by a casting method or the like, and then cured by irradiating an active energy ray (ultraviolet ray, electron beam). You.

Further, the above-mentioned resin liquid is supplied between the norbornene-based resin film (1) and the mold film and passed between rolls, so that the resin liquid is sandwiched between the two films and irradiated with active energy rays. Then, a method of curing can be adopted.

As the mold film in the latter method, a film such as a biaxially stretched polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate) film or a biaxially stretched polypropylene film is preferably used. Since the smoothness of the surface of the mold film can be arbitrarily selected, the use of this mold film allows the surface of the cured layer (2) to be made from a surface having extremely high smoothness to a rough surface (prevention of interference fringes, anti-glare) (They are intentionally provided with random fine irregularities or lens-like fine irregularities to impart properties or improve the incidence rate of incident light.)
Up to the desired smoothness or roughness.

<Transparent electrode (3)> On the cured layer (2),
A transparent electrode (3) is provided. As the transparent electrode (3), I
TO, InO ₂ , SnO ₂ , ZnO, Ag, Au, P
Layers such as t and Pd are mentioned, and ITO is particularly important. The transparent electrode (3) is formed by a sputtering method, an ion plating method, a vacuum evaporation method, a sol-gel method, a coating method, or the like, and is particularly preferably formed by a sputtering method. The transparent electrode (3) may have a multilayer structure.

The thickness of the transparent electrode (3) can be arbitrarily set as long as the transparency can be ensured.
It is often 00 angstrom, especially 150-600 angstrom.

Prior to the formation of the transparent electrode (3), an inorganic thin layer (t) such as a metal oxide, a metal nitride or a metal boride is provided on the cured layer (2), and the transparent electrode is formed thereon. (3) may be formed. The presence of the inorganic thin layer (t) is
(3) It is advantageous in terms of adhesion and, depending on the application, is advantageous in terms of moisture resistance, heat resistance, air resistance, acid and alkali resistance, and the like.

<Applications> The optical sheet of the present invention is particularly useful as a film with a transparent electrode for a touch panel (including a film used not only on a polarizing plate but also laminated below a polarizing plate). In this case, the transparent electrode (3) side of the two optical sheets obtained as described above may be opposed to each other, and a dot spacer having a thickness of, for example, about 0.02 to 1 mm may be interposed between the two sheets. . In this case, since the transparent electrode (3) on one sheet is usually a full-surface electrode and the transparent electrode (3) on the other sheet is usually a pattern electrode, the sheet to be a pattern electrode is formed after the full-surface electrode is formed. Resist formation, exposure, development, patterning by etching,
The cured resist is peeled off. As the processing solution at this time, for example, as a developing solution, a dilute aqueous solution of an alkali such as sodium carbonate or potassium carbonate, as an etching solution, an aqueous solution of ferric chloride or cupric chloride or an aqueous solution of an acid such as hydrochloric acid, As the resist stripping solution, an alkali stripping solution composed of an aqueous solution having a concentration of 1 to 5% by weight such as sodium hydroxide or potassium hydroxide is used. When an inner touch panel is used, the panel thus obtained is incorporated under a polarizing plate on the incident light side of a liquid crystal display element.

The optical sheet of the present invention is also useful as a substrate with a transparent electrode for a ferroelectric polymer liquid crystal display device. When producing a ferroelectric polymer liquid crystal display element, typically, the above-mentioned optical sheet and a counterpart sheet (this counterpart sheet may be glass) are
What is necessary is just to make the transparent electrode (3) side of these two sheets oppose, and to arrange a ferroelectric polymer liquid crystal layer between both sheets.

The optical sheet of the present invention can be used for other purposes such as an electrode substrate of a liquid crystal cell constituting a liquid crystal display element, an electrode substrate also serving as a polarizing plate, and an electrode substrate also serving as a phase plate.

<Function> In the optical sheet of the present invention, the norbornene-based resin film (1) as a base is subjected to an electric surface treatment, and the treated surface contains at least a part of an alicyclic epoxy resin. In addition to providing a cured layer (2) of an energy ray-curable epoxy resin, the cured layer
Since it has a layer configuration in which the transparent electrode (3) is provided from above (2), a strong adhesion between the base layer and the cured layer (2) is obtained, and the cured layer (2) and the transparent electrode (3) are obtained. 3) The adhesion between them is also good.

Accordingly, the norbornene-based resin film (1)
It is possible to provide a practical touch panel and a ferroelectric polymer liquid crystal display device while overcoming the difficulty of its application while keeping the inherent properties of the device as it is.

[0044]

The present invention will be further described with reference to the following examples.

Example 1 FIG. 1 is an explanatory view showing an example of an optical sheet of the present invention and a manufacturing process thereof.

As an example of a norbornene-based resin, a film (1) of “ZEONEX” manufactured by ZEON CORPORATION and having a thickness of 100 μm was prepared. This film (1) is produced by extrusion molding, and has a retardation of 4 nm.

After this film (1) was washed with ethanol, both surfaces thereof were subjected to a short-wavelength ultraviolet irradiation treatment under the following conditions.・ Ultraviolet irradiation equipment: UV surface modification equipment (Lab equipment, low pressure ultraviolet lamp) manufactured by Run Technical Service Co., Ltd. ・ Lamp: 200W synthetic quartz, grid type ・ Irradiation distance: 20mm ・ Irradiation time: 90 seconds, 120 seconds

Next, one of the treated surfaces (Side A) of the film (1) was coated with an ultraviolet-curable alicyclic epoxy resin solution having the following composition using a bar,
After drying for minutes, using a 120 W ultraviolet lamp,
Ultraviolet irradiation was performed under the conditions of an irradiation distance of 15 cm and an integrated amount of light of 908 mJ / cm ² to cure the film, thereby forming a cured layer (2) having a thickness of 10 μm. On the other processing side (B side) of the film (1),
Similarly, a cured layer (2) having a thickness of 10 μm was formed.

(Composition 1 of ultraviolet curing type epoxy resin liquid) 30% by weight of alicyclic epoxy resin ("Celoxide 2021" manufactured by Daicel Chemical Industries, Ltd.) 63% by weight of hydrogenated bisphenol A type epoxy resin ( "Epototo ST-300" manufactured by Toto Kasei Co., Ltd.
0 ") 2% by weight of photoinitiator (" OPTO "manufactured by Asahi Denka Co., Ltd.
MER SP-170 ") 5% by weight of isopropanol

The "celloxide 202" used above was used.
The chemical structure of “1” is as shown in the following chemical formula 1.

[0051]

Embedded image

For the film (1) after the formation of the cured layer (2),
The adhesion was measured. Table 1 shows the measurement results of the peel strength, and Table 2 shows the measurement results of the cross cut test. In each case, the number of measurements n was 5, and the average was determined. Seconds film
This is the time of the short wavelength ultraviolet irradiation treatment for (1).

[0053]

[Table 1]Peel strength (gf / inch)  A side Side B  0 seconds 90 seconds 120 seconds 0 seconds 90 seconds 120 seconds  1 15 230 240 17 260 210 2 23 180 270 22 225 260 3 21 210 300 22 255 240 4 18 205 315 19 230 2505 9 175 290 16 185 240  Average 17 200 283 19 231 240

[0054]

[Table 2]Cross cut test  A side Side B  0 seconds 90 seconds 120 seconds 0 seconds 90 seconds 120 seconds  1 0/100 100/100 100/100 0/100 100/100 100/100 2 0/100 100/100 100/100 0/100 100/100 100/100 3 0/100 100/100 100/100 0 / 100 100/100 100/100 4 0/100 100/100 100/100 0/100 100/100 100/1005 1/100 100/100 100/100 0/100 100/100 100/100  Average 0/100 100/100 100/100 0/100 100/100 100/100

Next, a 500 μm thick ITO as an example of a transparent electrode (3) was formed on one side (A side) of the sheet having the layer structure of (2) / (1) / (2) obtained above by sputtering. A layer was formed. The adhesion of the ITO layer was good.

On one side (side A) of the sheet having the layer structure of (2) / (1) / (2) obtained above, an SiO ₂ layer having a thickness of 90 Å as an example of the inorganic thin layer (t) was formed. Is formed by a sputtering method, and then a thickness of 500 μm as an example of the transparent electrode (3) is formed by a sputtering method in the same manner as described above.
m of the ITO layer was formed. At this time, the adhesion of the ITO layer was even better than the above.

The thus obtained (2) / (1) / (2) / (3) or (2) / (1) / (2) / (t) / (3) layer structure for optical use Using two sheets and forming a dot spacer on the transparent electrode (3) surface of one of the two sheets in accordance with a conventional method,
An inner touch panel (a touch panel disposed under a polarizing plate on the front side of a liquid crystal display element) was prepared by facing the transparent electrode (3) side of the two sheets. This inner touch panel did not cause delamination when repeated keying and pen input operations were performed, had a long service life, and sufficiently satisfied the strict standards of users.

Further, (2) / (1) / (2) / (3) obtained above or
(2) / (1) / (2) / (t) / (3) Two sheets of optical sheet having the layer structure of transparent electrode (3) are opposed to each other, and a ferroelectric polymer liquid crystal layer is interposed between the two sheets. Make a cell so that
When the ferroelectric polymer liquid crystal display element was manufactured, the life was very favorable.

Example 2 In the same manner as in Example 1, norbornene-based resin film
After performing the short-wavelength UV treatment on the surface of (1) (irradiation time was 120 seconds), a cured layer (2) was formed using the following UV-curable alicyclic epoxy resin solution, and then After forming an inorganic thin layer (t) from ITO, ITO was sputtered to form a transparent electrode (3). Table 3 shows the results.

(Composition 2 of UV-curable epoxy resin liquid) 40% by weight of alicyclic epoxy resin ("CELLOXIDE 2021" manufactured by Daicel Chemical Industries, Ltd.) 51% by weight of bisphenol A type epoxy resin (oilification) "Epicoat 828" manufactured by Shell Epoxy Co., Ltd.) 4% by weight of a photoinitiator ("OPTO" manufactured by Asahi Denka Co., Ltd.)
MER SP-150 ") 5% by weight of isopropanol

Example 3 In the same manner as in Example 1, norbornene-based resin film
After performing the short-wavelength UV treatment on the surface of (1) (irradiation time was 120 seconds), a cured layer (2) was formed using the following UV-curable alicyclic epoxy resin solution, and then After forming an inorganic thin layer (t) from ITO, ITO was sputtered to form a transparent electrode (3). Table 3 shows the results.

(Composition 3 of UV-curable epoxy resin liquid) 50% by weight of alicyclic epoxy resin ("CELLOXIDE 2081" manufactured by Daicel Chemical Industries, Ltd.) 46% by weight of a polyfunctional alicyclic epoxy resin ( "Eporide GT-30" manufactured by Daicel Chemical Industries, Ltd.) 4% by weight of a photoinitiator ("San Aid SI-100L" manufactured by Sanshin Chemical Co., Ltd.)

The "celloxide 208" used above was used.
The chemical structure of “1” is as follows.

[0064]

Embedded image

Example 4 Example 3 was repeated except that the surface of the norbornene-based resin film (1) was subjected to corona discharge treatment (level 4 × 3 passes) instead of the short-wavelength ultraviolet treatment. Table 3 shows the results.

[0066]

[Table 3]

Example 4 In the same manner as in Example 1, both surfaces of the film (1) were subjected to a short-wavelength ultraviolet irradiation treatment (irradiation time was 120 seconds).

The film (1) and the first mold film (M) are placed on a pair of rolls arranged in parallel with a slight gap.
₁ ) and discharge the ultraviolet-curable epoxy resin liquid used in Example 1 toward the gap between the rolls, and rotate both rolls in a direction to bite each other. Was cured, and the resin liquid was cured by irradiating ultraviolet rays in the state of being clamped to form a cured layer (2) having a thickness of 12 μm. Subsequently, the same operation was performed using the laminated film (1) / (2) / (M ₁ ) and the second mold film (M ₂ ) in this manner to obtain a cured layer (2) having a thickness of 13 μm. ) And none, (M ₂ ) / (2) / (1) / (2) /
A laminated film having a layer configuration of (M ₁ ) was obtained. Then, at an appropriate stage after that, the mold films (M ₁ ) and (M ₂ ) on both sides were peeled off. As the mold film (M ₁ ), a roughened biaxially stretched polyethylene terephthalate film having a surface roughness Ra of 0.15 μm on average was used. As the mold film (M ₂ ), a smooth biaxially stretched polyethylene terephthalate film was used. Was used.

On one side of the (2) / (1) / (2) film thus obtained (one side on the side of the mold film (M ₁ )), an inorganic thin layer (t) was formed in the same manner as in Example 1. ) Was formed, and ITO was sputtered to form a transparent electrode (3), whereby a target optical sheet was obtained.

Example 1 was prepared using the obtained optical sheet.
In the same manner as in the above, an inner touch panel was produced. This inner touch panel did not cause delamination when repeated keying and pen input operations were performed, had a long service life, and sufficiently satisfied the strict standards of users.

[0071]

As described in the section of action, in the optical sheet of the present invention, an active energy ray-curable resin containing at least a part of a norbornene-based resin film (1) and an alicyclic epoxy resin is used as a base. Cured layer of epoxy resin (2)
Strong adhesion is obtained. Also, its cured layer
The adhesion of the transparent electrode (3) provided from above (2) is also good. Therefore, the inherent properties of the norbornene-based resin film (1) (high transparency, low birefringence, high heat resistance,
Moisture and water resistance, acid and alkali resistance, polar solvent resistance, etc.)
The practical application of touch panels and ferroelectric polymer liquid crystals has been achieved, while overcoming the difficulties of application, remarkably improving the adhesion of transparent electrodes, and further improving the surface hardness, chemical resistance and solvent resistance. A display element can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of an optical sheet of the present invention and a manufacturing process thereof.

FIG. 2 is a view showing an example of a chemical structure of an alicyclic epoxy resin.

[Explanation of symbols]

 (1)… Norbornene resin film, (2)… Curing layer, (t)… Inorganic thin layer, (3)… Transparent electrode

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/141 G09F 9/30 348Z 5B087 G06F 3/033 360 G02B 1/10 Z 5C094 G09F 9/30 348 G02F 1/137 510 (72) Inventor Sanyo Fujimaki F-term (reference) 2F049 BA02 BA06 BB48 BC22 2H088 HA01 HA18 JA17 MA20 2H090 JB03 JD08 JD13 KA14 LA09 2K009 CC22 CC33 DD05 DD17 4F100 AA33C AA33E AK53B AK53D AK80A BA03 BA04 BA05 BA07 BA10B BA10C BA10D BA10E CA02B CA02D DD07B DD07D EH462 EJ08B EJ08D EJ192 EJ53A EJ531 EJ54A EJ541 EJ55A EJ551 EJ61A EJ611 GB41 JB14B JB14D JB142 JG01C JG01E JL11 JM02C JM02E JN01C JN01E 5B087 AA04 AA09 AE00 CC13 CC14 CC15 5C094 AA31 AA33 AA37 AA38 AA47 BA 49 DA13 EA05 EB01 EB02 FB01 FB15 GB10

Claims (6)

[Claims] A cured layer (2) of an active energy ray-curable epoxy resin containing at least a part of an alicyclic epoxy resin is provided on a treated surface of a norbornene resin film (1) which has been subjected to an electrical surface treatment. An optical sheet having a layer structure in which a transparent electrode (3) is provided on the cured layer (2). 2. The optical sheet according to claim 1, wherein the electric surface treatment is irradiation treatment with short-wavelength ultraviolet rays, corona discharge treatment, plasma treatment, or electron beam irradiation treatment. 3. The cured layer (2) is a layer obtained by coating the treated surface of the norbornene-based resin film (1) with a resin liquid and then irradiating it with an active energy ray or a norbornene-based resin film (1). A layer hardened by irradiating with an active energy ray in a state in which the resin liquid is supplied between the two films by supplying a resin liquid between the film and the mold film and passing between the rolls. Or the optical sheet according to 2. 4. The optical sheet according to claim 1, wherein the cured layer (2) is a layer obtained by irradiating ultraviolet rays in the presence of a cationic polymerization initiator to cure the epoxy resin. 5. The optical sheet according to claim 1, wherein the cured layer (2) provided on the treated surface of the norbornene-based resin film (1) has a rough surface. . 6. A substrate with a transparent electrode for a touch panel or a polymer ferroelectric liquid crystal display.
The optical sheet according to any one of the above.