JP6437080B1 - Gas barrier film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible gas barrier film having excellent gas barrier properties and high total light transmittance.
[Solution]
On the base material, a first metal oxide film, a second metal oxide film, and a third metal oxide film are laminated in this order, and the first metal oxide film is made of aluminum oxide, silicon oxide, and zinc. Excellent gas barrier characteristics by using a mixed oxide film with oxide, a second metal oxide film as a mixed oxide film of tin oxide and zinc oxide, and a third metal oxide film as a silicon oxide film Realize. Furthermore, a high total light transmittance can be realized by disposing the first metal oxide film and the third metal oxide film having a low refractive index on the substrate side and the side in contact with air, respectively.
[Selection] Figure 1

Description

  The present invention relates to a gas barrier film having a laminated structure.

  Conventionally, a gas barrier film using a plastic film or the like as a base material is sometimes used as an electronic device member such as a packaging material such as food and medical products, a display device, and a solar cell. The gas barrier film has a structure in which a gas barrier layer made of metal or metal oxide is formed on a base material in order to block gas such as oxygen and water vapor.

  Patent Document 1 discloses a laminated structure of a zinc oxide thin film layer made of a mixture of zinc oxide and a Group 13 and / or Group 14 metal oxide and an inorganic thin film layer made of an oxide of Si and / or Al. Discloses a gas barrier laminate film. It is described that by adding an oxide of a Group 13 and / or Group 14 metal, the crystal grains of the zinc oxide thin film layer are refined to improve the barrier property.

  Patent Document 2 discloses a gas barrier sheet having a laminated structure of an inorganic film formed of an oxide of an alloy of Zn and Sn, at least one of Si and Al, and an adhesive layer. . It is described that the acid component contained in the adhesive prevents corrosion of the alloy oxide of Zn and Sn and ensures long-term barrier properties.

JP 2013-208844 A Japanese Patent Laying-Open No. 2015-189011

  Although the conventional gas barrier film has excellent gas barrier properties, there is a problem that it is difficult to satisfy the demand for particularly high transparency such as display applications.

  In view of the above problems, an object of the present invention is to provide a gas barrier film that can simultaneously satisfy excellent gas barrier properties and high total light transmittance.

Gas barrier film according to the present invention,
A substrate;
A first metal oxide film, a second metal oxide film, and a third metal oxide film in order from the substrate side;
The first metal oxide film is made of a mixed oxide of silicon oxide, aluminum oxide and zinc oxide,
The second metal oxide film is made of a mixed oxide of tin oxide and zinc oxide,
The third metal oxide film is made of silicon oxide.

Gas barrier film according to the present invention,
The composition ratio of silicon and aluminum oxide in the first metal oxide film is 5.0 to 20.0 wt% and 0.5 to 5.0 wt%, respectively, and the balance is zinc oxide,
The composition ratio of tin oxide in the second metal oxide film is 20 to 40 wt%, and the balance is zinc oxide.
The composition ratio of oxygen (O) atoms to silicon (Si) atoms in the third metal oxide film is 1.8 to 2.0.

  The first metal oxide film and the second metal oxide film of the gas barrier film according to the present invention are films in which crystal grains are fine or amorphous, and metal oxides mixed with zinc oxide are different, respectively. The uppermost third metal film is a metal oxide film different from the second metal oxide film. Therefore, it is possible to have excellent gas barrier characteristics by adopting a laminated structure of these metal oxide films.

Gas barrier film according to the present invention,
The refractive index of the first metal oxide film is 1.59 to 1.8,
The refractive index of the second metal oxide film is 1.8 to 2.0,
The third metal oxide film has a refractive index of 1.4 to 1.5.

Gas barrier film according to the present invention,
The base material has a refractive index of 1.4 to 1.7.

An excellent gas barrier characteristic can be obtained by forming a third metal oxide film having a low refractive index directly in contact with air on the laminated structure of the first metal oxide film and the second metal oxide film. In addition, a high light transmittance can be realized.
That is, since the second metal oxide film has a refractive index of 1.8 to 2.0 and a large difference from the refractive index of air, when the air and the second metal oxide film are in direct contact with each other, The transmittance decreases due to the reflection of light at these interfaces. However, by forming the third metal oxide film having a low refractive index in the uppermost layer in contact with air, it is possible to suppress the reflection of light and increase the transmittance, particularly the total light transmittance.
Moreover, by forming a first metal oxide film having a refractive index of 1.59 to 1.8 on the substrate side on a plastic film substrate having a refractive index of 1.4 to 1.7, for example. The reflection of light at the interface with the substrate can be suppressed, and the transmittance can be improved.
As a result, it is possible to satisfy 90%, which is a required value of transmittance particularly for display applications.
Strictly speaking, silicon (Si) is a semiconductor, but in this specification, it is included in a metal in a broad sense, and “silicon oxide” is included in a metal oxide in a broad sense.

Gas barrier film according to the present invention,
The thickness of the first metal oxide film is 10 to 300 nm,
The thickness of the second metal oxide film is 10 to 300 nm,
The third metal oxide film has a thickness of 5 to 100 nm.

  By adopting such a first metal oxide film, second metal oxide film, and third metal oxide film thickness structure, the gas barrier film has flexibility (flexibility), excellent barrier properties, and high total light. It is possible to achieve both the transmittance.

Gas barrier film according to the present invention,
A smoothing layer is included between the base material and the first metal oxide film.

Gas barrier film according to the present invention,
A smooth layer including a polysilazane layer is included between the base material and the first metal oxide film.

By adopting such a configuration, the first metal oxide film can be formed on the smoothed surface formed on the base material, thereby reducing the occurrence of defects in the first metal oxide film. can do.
Furthermore, the smooth layer has a polysilazane layer having a Si—O bond, and the smooth layer and the first metal oxide film are brought into direct contact with the polysilazane layer and the first metal oxide film containing silicon oxide. Adhesiveness can be improved.

Gas barrier film according to the present invention,
A resin layer is provided on the third metal oxide film.

The gas barrier film according to the present invention is
A protective film is laminated on the third metal oxide film.

  With such a configuration, it is possible to prevent the occurrence of scratches and the like on the surface of the third metal oxide film, and it is possible to prevent the gas barrier characteristics from being deteriorated due to the scratches or the like.

The gas barrier film according to the present invention is
A resin film provided with a functional layer is laminated on the third metal oxide film via an adhesive layer or an adhesive layer.

  Thus, by providing the resin film which provided the functional layer, for example, a transparent conductive layer, on the 3rd metal oxide film, a gas barrier film can be used for a touch panel or a solar cell use, for example.

According to the present invention, a gas barrier film having a high total light transmittance and an excellent gas barrier property can be provided.
In particular, the gas barrier film according to the present invention can satisfy a high demand for transparency for display applications.

Sectional drawing which shows the laminated structure of the gas barrier film which concerns on Embodiment 1. FIG. Sectional drawing which shows the laminated structure of the gas barrier film which concerns on Embodiment 2. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, none of the following embodiments gives a limited interpretation in the recognition of the gist of the present invention. The same or similar members are denoted by the same reference numerals, and the description thereof may be omitted.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing an example of a gas barrier film according to Embodiment 1 of the present invention. The gas barrier film is formed on a substrate 1 in order, a first metal oxide film 2 and a second metal oxide film 3. The third metal oxide film 4 is laminated.
<Base material>
The base material 1 is not particularly limited as long as it is in the form of a sheet. For example, PET (polyethylene terephthalate), COP (cycloolefin polymer), PE (polyethylene), PI (polyimide), etc., which are plastic films, are used. In addition, a glass plate may be used.
In particular, by selecting a material having flexibility (flexibility) such as a plastic film as the base material 1, it can be used for a wide range of applications such as packaging materials and electronic device members such as solar cell panels and display devices. Can be used.

In addition, each metal oxide film, which will be described later, as a gas barrier layer formed on the substrate 1 can be formed using a known vapor deposition method, sputtering method, or CVD method, but the substrate 1 has flexibility. In this case, a known roll-to-roll film forming apparatus can be used.
The film forming apparatus is not limited to the roll-to-roll system, and may be a system in which each metal oxide film is formed with the base material 1 placed on a susceptor in the film forming apparatus.

<First metal oxide film>
A first metal oxide film 2 is formed on the substrate 1 as a first gas barrier layer.
As the first metal oxide film 2, a mixed target of aluminum (Al) oxide, silicon (Si) oxide, and zinc (Zn) oxide is used, and aluminum is formed by reactive sputtering using a mixed gas of argon and oxygen. An oxide film in which an oxide, a silicon oxide, and a zinc oxide are mixed (hereinafter referred to as an Al—Si—Zn oxide film for simplicity) is formed to a thickness of 10 nm to 300 nm, preferably 90 nm to 110 nm.
If the film thickness is too thin, the target gas barrier property cannot be exhibited. If it is too thick, the gas barrier property may be impaired due to cracks caused by stress. Furthermore, the flexibility is poor. By setting the film thickness within the above range, gas barrier properties and flexibility can be satisfied.

  Note that the Al—Si—Zn oxide film may inevitably contain other elements as impurities due to problems in material purification technology (for example, due to the finite purity of the sputtering target).

The composition ratio of aluminum oxide, silicon oxide, and zinc oxide in the Al-Si-Zn oxide film is aluminum oxide, where the total amount of aluminum oxide, silicon oxide, and zinc oxide is 100 wt% (weight percent). Is 0.5 to 5.0 wt%, silicon oxide is 5.0 to 20.0 wt%, and zinc oxide is the balance, that is, (100- [composition ratio of aluminum oxide]-[composition ratio of silicon oxide] ) Wt%.
Under this composition ratio condition, the refractive index, which is the optical characteristic of the Al—Si—Zn oxide film, is 1.59 to 1.8.

  The Al—Zn oxide film is a crystalline film, and water vapor permeates between crystal grains, so that the gas barrier property is lowered. By adding Si, it becomes amorphous and exhibits high gas barrier properties.

Furthermore, since the Al—Si—Zn oxide film that is the first metal oxide film 2 is composed of three kinds of metal oxides having different refractive indexes, by adjusting the composition of each metal oxide, Al The refractive index of the —Si—Zn oxide film can be adjusted. For example, the refractive index of aluminum oxide and silicon oxide is lower than that of zinc oxide. In particular, the refractive index can be lowered by increasing the composition ratio of silicon oxide having the lowest refractive index.
In the case where a sputtering method is employed as the film formation method, the composition ratio of each metal oxide in the Al—Si—Zn oxide film can be adjusted by the composition of the target.

  Thus, by using a film made of three kinds of metal oxides as the first metal oxide film 2, it is possible to achieve both control of the refractive index and amorphous.

  When, for example, PET, COP, PE, or PI, which is a plastic material having flexibility (flexibility), is used as the material of the base material 1, the refractive index thereof is typically 1.4 to 1.7. . Therefore, the metal composition ratio of the first metal oxide film 2 is adjusted so that the refractive index of the first metal oxide film 2 is close to the refractive index of the plastic material, for example, the difference in refractive index is 0.2 or less. By adjusting, it is possible to suppress reflection at the interface between the substrate 1 and the first metal oxide film 2, improve transparency (total light transmittance), and realize high barrier characteristics. .

<Second metal oxide film>
A second metal oxide film 3 is formed on the first metal oxide film 2 as a second gas barrier layer.
As the second metal oxide film 3, a mixed target of tin oxide (SnO ₂ ) and zinc oxide (ZnO) is used, and tin oxide and zinc oxide are formed by reactive sputtering using a mixed gas of argon and oxygen. A metal oxide film (hereinafter referred to as a Sn—Zn oxide film for simplicity) is formed on the first metal oxide film 2. That is, the oxide mixed with the zinc oxide of the second metal oxide film 3 is tin oxide, and the oxide (aluminum oxide and silicon oxide) mixed with the zinc oxide of the first metal oxide film 2. And different oxides are used.
Note that other elements may be inevitably mixed in the Sn—Zn oxide film as an impurity due to problems in material purification technology.

The thickness of the second metal oxide film 3 to be formed is 10 nm to 300 nm, preferably 90 nm to 110 nm.
If the film thickness is too thin, the target gas barrier property cannot be exhibited. If it is too thick, cracks due to stress may occur, which may impair gas barrier properties. Furthermore, the flexibility is poor. By setting the film thickness within the above range, gas barrier properties and flexibility can be satisfied.

The composition ratio (content ratio) of tin oxide and zinc oxide in the Sn—Zn oxide film is 20 to 40 wt% (weight percent) for tin oxide and 60 to 80 wt% for zinc oxide.
Under these composition conditions, both the tin oxide and the zinc oxide have a higher refractive index than that of aluminum oxide or silicon oxide, and therefore the refractive index, which is the optical characteristic of the Sn—Zn oxide film, is 1. 8 to 2.0.
Note that the composition ratio of tin oxide and zinc oxide can be adjusted by the composition of the target when the sputtering method is employed.

Since the Sn—Zn oxide film contains tin oxide and zinc oxide, it becomes an amorphous film as compared with a film made of zinc oxide, and has excellent gas barrier properties, that is, a gas such as water vapor or oxygen. The film has a low transmittance.
As described above, the refractive index of the Sn—Zn oxide film, which is the second metal oxide film 3, is higher than the refractive index of the substrate 1, and the difference in refractive index between the two becomes large, but the refractive index is the second refractive index. By interposing the first metal oxide film 2 lower than the refractive index of the metal oxide film 3 between the second metal oxide film 3 and the base material 1, a decrease in transmittance due to the difference in refractive index is suppressed. ing.

Further, by stacking the second metal oxide film 3 which is a different material on the first metal oxide film 2, for example, even when a defect occurs in each metal oxide film, a gas such as water vapor or oxygen Since it can prevent that the defect used as a permeation | transmission path | route continues, the barrier property of gas can further be improved.
In particular, since the first metal oxide film 2 and the second metal oxide film 3 are different in the metal oxide mixed with the zinc oxide, it is possible to effectively prevent a defect that becomes a gas permeation path from continuing. .

<Third metal oxide film>
A third metal oxide film 4 is formed on the second metal oxide film 3 as a third gas barrier layer.
As the third metal oxide film 4, for example, a silicon (Si) target is used, and a silicon oxide film (hereinafter referred to as a SiOx film for the sake of simplicity. Here, x = 1) by sputtering using a mixed gas of argon and oxygen. .8-2.0.).
Note that other elements may inevitably be mixed into the silicon oxide film as impurities due to problems in the material purification technique.

  When the SiOx film is thick, for example, 100 nm or more, cracks are generated and the barrier characteristics are deteriorated. Moreover, since the stable gas barrier property cannot be ensured if the film thickness is too thin, the film thickness of the SiOx film is preferably 5 to 100 nm.

  As described above, the refractive index of the second metal oxide film 3 is high, and the difference from the refractive index of air becomes large. Therefore, when the second metal oxide film 3 is in direct contact with air, the light at the interface of The transmittance decreases due to reflection. However, the refractive index, which is the optical characteristic of the SiOx film, is 1.4 to 1.5, and silicon oxide (SiOx) is used as the third metal oxide film 4 having a low refractive index on the second metal oxide film 3. By forming, the difference from the refractive index of air can be reduced.

  That is, the laminated structure of the first metal oxide film 2 and the second metal oxide film 3 has excellent gas barrier characteristics, but the second metal oxide film in the upper layer has a refractive index of 1.8 to 2. 0, the difference in refractive index from air is large, and the transmittance is reduced to, for example, about 77%. However, the gas barrier film according to the present invention can increase the transmittance to 92% by forming the third metal oxide film having a low refractive index in the uppermost layer in contact with air.

  Further, since the silicon oxide film (SiOx) itself has a gas barrier property and is an oxide of a metal that is completely different from the second metal oxide film 3, the second metal oxide film 3 and the third metal oxide film are used. It is possible to effectively prevent a defect that becomes a gas permeation path from being continuous with the gas.

Note that in the case where the gas barrier film has a two-layer structure including only an Al—Zn—Si oxide film and a silicon oxide film, the film thickness must be set thick in order to obtain the necessary gas barrier properties.
However, when the film thickness is increased, the flexibility of the gas barrier film may be impaired. Therefore, by stacking a Sn—Zn oxide film having a higher gas barrier property per unit film thickness than the Al—Zn—Si oxide film, the film thickness can be reduced, so that flexibility is improved even with the same gas barrier property. be able to.

In this way, the second metal oxide film 3 having a high refractive index is sandwiched between the first metal oxide film 2 and the third metal oxide film 4 having a relatively low refractive index, and the substrate 1 and By arranging the first metal oxide film 2 having a close refractive index on the base material 1 and the third metal oxide film 4 on the side in direct contact with air, the total light transmittance is effectively improved. be able to.
Furthermore, since the first metal oxide film 2, the second metal oxide film 3, and the third metal oxide film 4 are made of different metal oxides, there is an effect that defects that can become gas permeation paths are continuous. Can be prevented.
Therefore, the gas barrier film according to the present invention can achieve high gas barrier properties and can satisfy the required transmittance of 90% for display applications, and can be used not only for packaging materials but also for electronic device members. Can be applied.

(Embodiment 2)
As shown in FIG. 2A, the smooth layer 5 that improves the flatness of the surface may be formed on the base material 1, and the first metal film 2 may be formed on the smooth layer 5.
By forming the first metal oxide film 2 on the flat surface of the smoothing layer 5, it is possible to suppress the occurrence of defects (for example, cracks) in the first metal oxide film 2 and further improve the gas barrier characteristics. it can.

  However, the flat surface of the smooth layer 5 means that the contact area between the smooth layer 5 and the first metal oxide film 2 is reduced. When the contact area between the smooth layer 5 and the first metal oxide film 2 is reduced, the mutual adhesion is reduced.

Therefore, polysilazane having a Si—O bond can be suitably used as a material constituting the smooth layer 5.
This is because the first metal oxide film 2 contains silicon oxide, so that the adhesion between the smooth layer 5 made of polysilazane and the first metal oxide film 2 can be improved.

The polysilazane layer constituting the smooth layer 5 can be formed by, for example, applying a perhydropolysilazane (PHPS) solution on the base material 1, for example, spray coating, and curing by applying UV light.
The polysilazane layer formed in this way has a smooth surface, but in particular, when the surface roughness Ra is 1 nm or less, generation of defects in the first metal oxide film 2 formed on the polysilazane layer is prevented. Can be suppressed. Furthermore, since the surface of the first metal oxide film 2 is also flattened, defects in the second metal oxide film 3 and the third metal oxide film 4 can be suppressed.

  The polysilazane layer constituting the smooth layer 5 has Si—H, Si—N, and Si—O bonds, but is cured in an oxidizing atmosphere to form a layer that is further oxidized in the surface layer. It is possible to improve the adhesion between the first metal oxide film 2 and the polysilazane layer that is the smooth layer 5.

Further, the smooth layer 5 may have a two-layer structure as shown in FIG. 2B, and the first smooth layer 5 a and the second smooth layer 5 b may be formed in order from the surface of the substrate 1.
That is, the second smooth layer 5b may be a layer made of polysilazane, and the first smooth layer 5a may be a layer made of a material different from polysilazane by a coating method or the like.

By planarizing the surface with the first smoothing layer 5a and then forming a polysilazane layer as the second smoothing layer 5b, a surface with even better flatness can be obtained.
In this case, high adhesion is maintained between the substrate 1 and the first metal oxide film 2 by forming the first metal oxide film 2 directly on the second smooth layer 5b, which is a polysilazane layer. can do.

  As a material used for forming the smooth layer 5a, an actinic radiation curable resin-based paint or a thermosetting resin-based paint that is cured through a crosslinking reaction or the like by irradiation with active energy rays such as ultraviolet rays or electron beams can be suitably used. . In particular, an ultraviolet curable resin-based coating that is cured by ultraviolet irradiation is preferable, and an ultraviolet curable organic-inorganic hybrid resin coating is more preferable.

The smooth layer 5a of the organic-inorganic hybrid resin is particularly preferable because it can improve the interlayer adhesion between the plastic substrate and the polysilazane layer. Since most of the organic-inorganic hybrid resin is an organic component, it has good adhesion to a plastic substrate that is an organic material.
Moreover, since Si component is also contained in resin, the adhesiveness with the polysilazane layer laminated | stacked on the upper part is also favorable.

In addition, the roughness of the smooth layer surface is also important in order to have good gas barrier properties.
As for the roughness of the smooth layer surface, Ra is 1.0 nm or less, preferably 0.8 nm or less, and Rz is 20 nm or less, preferably 10 nm or less.

  As a coating method, for example, a gravure coating method, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, or the like can be used. As an ultraviolet light source for photopolymerizing an ultraviolet curable resin, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.

In the gas barrier film according to the present invention, a resin layer having a thickness of, for example, several μm may be provided on the third metal oxide film 4 in order to protect the metal oxide film. The protective resin layer can be actinic ray curable resin paint or thermosetting resin paint, and is laminated with acrylic resin, urethane resin, epoxy resin, etc. so as not to impair transparency. . The protective resin layer has a thickness of about 5 μm or less in order to prevent adverse effects such as curling on the gas barrier film.
Further, a protective film (for example, several tens of μm), for example, a film in which an adhesive layer is provided on an olefin-based resin film such as polyethylene or polypropylene to protect the metal oxide film on the third metal oxide film 4, PET A film in which an adhesive layer such as an acrylic resin or a urethane resin is coated on a resin film may be laminated. The protective film is for temporarily protecting the surface of the gas barrier film and is premised on peeling, and therefore does not require transparency. Moreover, in order to prevent damage to the gas barrier film at the time of peeling, the adhesive strength of the protective film is at most about 0.5 N / 25 mm or less.
By providing a flexible protective resin layer or protective film, it is possible to prevent the first, second, and third metal films 2, 3, and 4 from being mechanically damaged, for example, and to have a barrier property. Can be prevented from deteriorating.

In addition, the gas barrier film according to the present invention is a resin film in which a functional layer such as a transparent conductive layer is provided on the third metal oxide film 4 via a known adhesive layer or adhesive layer, for example, several tens. ˜200 μm may be laminated.
By providing a resin film provided with a functional layer, the gas barrier film can be used, for example, for touch panels and solar battery applications.

  According to the present invention, it is possible to obtain a gas barrier film having gas barrier properties that are excellent in gas barrier properties and have high total light transmittance, and can be widely applied not only to packaging materials but also to electronic device members such as displays. The industrial applicability is great.

DESCRIPTION OF SYMBOLS 1 Base material 2 1st metal oxide film 3 2nd metal oxide film 4 3rd metal oxide film 5 Smooth layer 5a 1st smooth layer 5b 2nd smooth layer

Claims (7)

On a sheet-like substrate having flexibility,
A gas barrier film having a laminated structure composed of a first metal oxide film, a second metal oxide film, and a third metal oxide film in order from the substrate side,
The first metal oxide film is made of a mixed oxide of silicon oxide, aluminum oxide and zinc oxide,
The second metal oxide film is made of a mixed oxide of tin oxide and zinc oxide,
The third metal oxide film is made of silicon oxide,
The base material has a refractive index of 1.4 to 1.7,
The refractive index of the first metal oxide film is 1.59 to 1.8,
The refractive index of the second metal oxide film is 1.8 to 2.0,
The refractive index of the third metal oxide film, Ri 1.4-1.5 der,
The thickness of the first metal oxide film is 90 to 110 nm,
The film thickness of the second metal oxide film is 90 to 110 nm,
The gas barrier film, wherein the third metal oxide film has a thickness of 5 to 100 nm . The composition ratio of silicon and aluminum oxide in the first metal oxide film is 5.0 to 20.0 wt% and 0.5 to 5.0 wt%, respectively, and the balance is zinc oxide,
The composition ratio of tin oxide in the second metal oxide film is 20 to 40 wt%, and the balance is zinc oxide.
2. The gas barrier film according to claim 1, wherein a composition ratio of oxygen (O) atoms to silicon (Si) atoms in the third metal oxide film is 1.8 to 2.0. The gas barrier film according to claim 1 or 2 characterized in that it comprises a smooth layer between the substrate first metal oxide film. The gas barrier film according to any one of claims 1 to 3 , further comprising a smooth layer including a polysilazane layer between the base material and the first metal oxide film. The gas barrier film according to any one of claims 1 to 4 , further comprising a resin layer on the third metal oxide film. The gas barrier film according to any one of claims 1 to 4 , wherein a protective film is laminated on the third metal oxide film. The gas barrier film according to any one of claims 1 to 4 , wherein a resin film provided with a functional layer is laminated on the third metal oxide film through an adhesive layer or an adhesive layer.

Images