JP2017189879A - Light-emitting body protective film, wavelength conversion sheet, and electroluminescent light-emitting unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting body protective film that can prevent the occurrence of a dark spot even when having a defect in a barrier layer when it is used for a light-emitting unit.SOLUTION: The present invention provides a light-emitting body protective film that has: a barrier film having a first substrate layer and a barrier layer formed on the first substrate layer; and a second substrate layer. The second substrate layer is bonded on a face of the barrier film on the barrier layer side through an adhesion layer, and the adhesion layer has an oxygen permeability at thickness 5 μm of 100 cm/(mday atm) or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitter protective film, a wavelength conversion sheet, and an electroluminescence light emitting unit.

  In a light emitting unit such as a backlight unit of a liquid crystal display and an electroluminescence light emitting unit, the performance as a light emitter may be deteriorated when a long time elapses when the light emitter comes into contact with oxygen or water vapor. For this reason, in these light emitting units, a gas barrier film in which a gas barrier layer is formed on a polymer film is often used as a protective film for a light emitter (see, for example, Patent Document 1).

International Publication No. 2015/013225

  However, in the production of the protective film, when the gas barrier layer is formed, damages due to contamination of foreign matters and micro defects such as cracks may occur in the gas barrier layer. In addition, for example, when the gas barrier layer is formed by a vapor deposition method and the vapor deposition material is splashed, a large defect is generated in the gas barrier layer. In some cases, a defect penetrating the polymer film and the gas barrier layer is generated. It can happen. These defects become intrusion paths for oxygen or water vapor. As a result, when a protective film having the above defects in the gas barrier layer is used in a light emitting unit, a dark spot may be generated at a location near the above defects.

  The present invention has been made in view of the above problems, and when used in a light emitting unit, a light emitter protective film capable of suppressing the occurrence of dark spots even if the barrier layer has a defect, and It aims at providing the wavelength conversion sheet | seat and electroluminescent light emitting unit which are obtained using this.

The present invention includes a barrier film including a first base material layer and a barrier layer formed on the first base material layer, and a second base material layer, wherein the second base material layer is the above-described barrier film. A phosphor protective film that is bonded to the surface on the barrier layer side through an adhesive layer, and the oxygen permeability of the adhesive layer is 100 cm ³ / (m ² · day · atm) or less at a thickness of 5 μm. provide.

According to the phosphor protective film of the present invention, when the barrier film and the second base material layer are bonded to each other, when used in the light emitting unit, the phosphor layer is prevented from being damaged by an external force, and the gas barrier property is stabilized. Can be obtained. Furthermore, when the oxygen permeability of the adhesive layer is 100 cm ³ / (m ² · day · atm) or less, even if the phosphor protective film has a defect in the barrier layer, generation of dark spots is prevented. Can be suppressed.

  The first substrate layer is preferably a polyethylene terephthalate film or a polyethylene naphthalate film, and the second substrate layer is preferably a polyethylene terephthalate film or a polyethylene naphthalate film. By providing the first base material layer and the second base material layer with the above-described configuration, a further excellent gas barrier property can be obtained.

  In the light emitter protective film, the adhesive layer is preferably formed of an adhesive containing an epoxy resin. When the adhesive layer has the above configuration, the adhesion between the barrier film and the second base material layer can be improved.

  In the phosphor protective film, the barrier layer preferably includes an inorganic thin film layer and a gas barrier coating layer. When the barrier layer has the above-described configuration, a further excellent gas barrier property can be obtained.

  It is preferable that the luminous body protective film further includes an adhesion layer formed on the surface of the barrier film opposite to the second base material layer. When the light emitter protective film includes the adhesion layer, adhesion with the light emitter layer can be improved. For this reason, it becomes easy to employ | adopt a wide combination for the material of a 1st base material layer and a light-emitting body layer.

  It is preferable that the luminous body protective film further includes a coating layer formed on a surface of the second base material layer opposite to the barrier film. In the phosphor protective film, the coating layer preferably contains a binder resin and fine particles dispersed in the binder resin. When the light emitter protective film includes the coating layer, a light diffusion function can be obtained, and an antireflection function and a more excellent interference fringe prevention function can be obtained.

  The present invention also provides a wavelength conversion sheet comprising: the light emitter protective film; and a phosphor layer formed on the barrier film side surface of the light emitter protective film.

  The present invention also provides an electroluminescence light-emitting unit comprising the above-described phosphor protection film and an electroluminescence phosphor layer formed on the barrier film side surface of the phosphor protection film.

  According to the present invention, when used in a light emitting unit, a light emitter protective film capable of suppressing the occurrence of dark spots even if the barrier layer has a defect, and wavelength conversion obtained using the same Sheets and electroluminescent light emitting units can be provided.

It is a schematic sectional drawing which shows the light-emitting body protective film which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows the light-emitting body protective film which concerns on another embodiment of this invention. It is a schematic sectional drawing which shows the light-emitting body protective film which concerns on another embodiment of this invention. It is a schematic sectional drawing of the wavelength conversion sheet which concerns on one Embodiment of this invention. It is a conceptual diagram which shows the mechanism of a dark spot generation | occurrence | production assumed in the wavelength conversion sheet which has a defect in a barrier layer. It is a schematic sectional drawing of the backlight unit obtained using the wavelength conversion sheet which concerns on one Embodiment of this invention. It is a schematic sectional drawing of the electroluminescent light emission unit which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment.

(Light Emitter Protection Film)
FIG. 1 is a schematic cross-sectional view showing a light emitter protective film according to an embodiment of the present invention. In FIG. 1, the light emitter protective film 10 includes a barrier film 16 and a second base material layer 11b, and the barrier film 16 includes a first base material layer 11a and a barrier layer 14 formed on the first base material layer 11a. Including. The second base material layer 11 b is bonded to the surface of the barrier film 16 on the side of the barrier layer 14 via the adhesive layer 15. The barrier film 16 may include two or more barrier layers 14. When the barrier film 16 includes two or more barrier layers 14, the configuration of the plurality of barrier layers 14 may be the same or different. When the light emitter protective film 10 is used in a light emitting unit, the light emitter protective film 10 is preferably arranged so that the barrier film 16 is in contact with the light emitter layer.

The oxygen permeability of the adhesive layer 15 is 100 cm ³ / (m ² · day · atm) or less in the thickness direction at a thickness of 5 μm. The oxygen permeability is preferably 50 cm ³ / (m ² · day · atm) or less, and more preferably 10 cm ³ / (m ² · day · atm) or less. When the oxygen permeability of the adhesive layer 15 is 100 cm ³ / (m ² · day · atm) or less, even when the barrier layer has a defect, it suppresses dark spots when used in the light emitting unit. The light emitter protective film 10 that can be obtained can be obtained. The lower limit value of the oxygen permeability is not particularly limited, and is, for example, 0.1 cm ³ / (m ² · day · atm).

  The luminous body protective film 10 according to the present embodiment provides excellent gas barrier properties due to the barrier layer 14. However, the gas barrier property of the protective film as a whole can be obtained by the barrier layer, but when a local microdefect occurs in the barrier layer, dark spots are generated in the phosphor layer near the microdefect generated in the barrier layer. May not be sufficiently suppressed. Such local micro defects hardly appear in the gas barrier property of the entire protective film evaluated by measuring the gas permeability, but affect the generation of dark spots in the vicinity of the defects. Even if the local light defect has arisen in the barrier layer by sticking the barrier film 16 and the 2nd base material layer 11b through the contact bonding layer 15, the luminous body protective film 10 which concerns on this embodiment, Generation of dark spots in the vicinity of the defect can be suppressed. In addition, the effect obtained by the light emitter protection film 10 according to the present embodiment is not limited to the case where the micro defect occurs, and even if a large defect occurs in the barrier layer during the production of the protective film, the vicinity of the defect The generation of dark spots can be suppressed. Furthermore, according to the light emitter protection film 10 according to the present embodiment, even if a defect penetrating the barrier film (both the barrier layer and the first base material layer) occurs during the production of the protective film, the defect Generation of dark spots in the vicinity can be suppressed.

  The adhesive layer 15 is formed from an adhesive or an adhesive. Examples of the adhesive include acrylic adhesives, epoxy adhesives, urethane adhesives, and the like. The adhesive preferably includes an epoxy resin. When the adhesive contains an epoxy resin, the adhesion between the barrier film 16 and the second base material layer 11b can be improved. Examples of the pressure-sensitive adhesive include acrylic pressure-sensitive adhesives, polyvinyl ether-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, and starch paste-based adhesives. The thickness of the adhesive layer 15 is preferably 0.5 to 50 μm, more preferably 1 to 20 μm, and further preferably 2 to 6 μm. When the thickness of the adhesive layer 15 is 0.5 μm or more, adhesion between the barrier film 16 and the second base material layer 11b can be easily obtained, and when the thickness is 50 μm or less, the adhesive layer 15 is more excellent. Gas barrier properties are easily obtained.

  The 1st base material layer 11a and the 2nd base material layer 11b are layers for controlling breakage in processing, distribution, etc. Examples of the first base layer 11a and the second base layer 11b include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as nylon; polyolefins such as polypropylene and cycloolefin; polycarbonates; Although the film which consists of cellulose etc. is mentioned, it is not limited to these. The first base material layer 11a and the second base material layer 11b are preferably a polyester film, a polyamide film or a polyolefin film, more preferably a polyester film or a polyamide film, and a polyethylene terephthalate film or a polyethylene naphthalate film. More preferably it is. When the first base material layer 11a and the second base material layer 11b are a polyethylene terephthalate film or a polyethylene naphthalate film, further excellent gas barrier properties can be obtained. Moreover, it is preferable that the 1st base material layer 11a and the 2nd base material layer 11b are biaxially stretched. The first base material layer 11a and the second base material layer 11b may be the same or different.

  Although the thickness in particular of the 1st base material layer 11a and the 2nd base material layer 11b is not restrict | limited, It is preferable that they are 3 micrometers or more and 100 micrometers or less, and it is more preferable that they are 5 micrometers or more and 50 micrometers or less.

  A barrier layer 14 is formed on the first base material layer 11a through an anchor coat layer (not shown) as necessary. A polyester resin etc. are mentioned as an anchor coat layer, and the thickness of an anchor coat layer is about 0.01-1 micrometer.

  The barrier layer 14 preferably has an inorganic thin film layer 12 and a gas barrier coating layer 13. By providing the barrier layer 14 with the above-described configuration, more excellent gas barrier properties can be obtained. Moreover, by arrange | positioning the 2nd base material layer 11b on the surface at the side of the barrier layer 14 of the barrier film 16, the barrier layer 14 can be protected from external force and more stable gas barrier property can be acquired. In addition, it can replace with the 2nd base material layer 11b, and if the same layer as the barrier film 16 is arrange | positioned and it is set as the laminated structure of a barrier film, it is also possible to obtain the further outstanding gas barrier property. However, the light emitter protective film 10 according to the present embodiment can obtain a sufficient gas barrier property without having the laminated structure, and can be produced at a low cost without going through the production process of the laminated layer. Is possible. Furthermore, the light emitter protection film 10 according to this embodiment can also reduce the occurrence of interference fringes (moire).

The inorganic thin film layer 12 contains an inorganic compound and preferably contains a metal oxide. Examples of the metal oxide include oxides of metals such as aluminum, copper, silver, yttrium, tantalum, silicon, and magnesium. Since the metal oxide is inexpensive and excellent in barrier performance, it is preferably silicon oxide (SiO _x , x is 1.0 to 2.0). When x is 1.0 or more, good gas barrier properties tend to be obtained.

  The method for forming the inorganic thin film layer 12 is preferably vacuum film formation. Examples of vacuum film formation include physical vapor deposition and chemical vapor deposition. Examples of physical vapor deposition include vapor deposition, sputtering, and ion plating. Examples of the chemical vapor deposition method include a thermal CVD method, a plasma CVD method, and a photo CVD method. From the viewpoint of manufacturing cost, the inorganic thin film layer 12 is preferably an inorganic vapor deposition film layer formed by a vapor deposition method. For example, when the inorganic thin film layer 12 is an inorganic vapor deposition film layer, a hole may be generated in the barrier film 16 due to scattering (splash) of the vapor deposition material. Although the frequency of splashing is low, the holes created by the splash are relatively large defects and can be holes that penetrate the barrier layer and the substrate layer. Therefore, in the protective film in which the holes due to the splash are generated, the gas barrier property can be greatly reduced. When a hole penetrating the barrier layer 14 and the first base material layer 11a is generated, dark spots are more easily generated. However, since the barrier film 16 and the second base material layer 11b are bonded to each other through the adhesive layer 15 in the light emitter protective film 10 according to this embodiment, the barrier film 16 has a relatively large defect. Even so, the occurrence of dark spots can be suppressed as in the case where there is no such defect. Therefore, when the inorganic thin film layer 12 is an inorganic vapor deposition film layer, generation | occurrence | production of a dark spot can be suppressed, reducing manufacturing cost.

  The thickness of the inorganic thin film layer 12 is preferably 10 to 300 nm, and more preferably 20 to 100 nm. When the thickness of the inorganic thin film layer 12 is 10 nm or more, a uniform film tends to be obtained and gas barrier properties tend to be easily obtained. On the other hand, when the thickness of the inorganic thin film layer 12 is 300 nm or less, the inorganic thin film layer 12 can be kept flexible, and cracks and the like tend not to occur due to external forces such as bending and tension after film formation. is there.

The gas barrier coating layer 13 is preferably formed from a composition containing at least one selected from the group consisting of a metal alkoxide represented by the following formula (1) and a hydrolyzate thereof.
M (OR ¹ ) _m (R ² ) _nm (1)

In the above formula (1), a monovalent organic group having 1 to 8 carbon atoms R ¹ and R ² are each independently preferably an alkyl group such as a methyl group, an ethyl group. M represents an n-valent metal atom such as Si, Ti, Al, or Zr. m is an integer of 1 to n. Examples of the metal alkoxide include tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ], triisopropoxyaluminum [Al (O-iso-C ₃ H ₇ ) ₃ ] and the like. The metal alkoxide is preferably tetraethoxysilane or triisopropoxyaluminum because it is relatively stable in an aqueous solvent after hydrolysis. Examples of the hydrolyzate of the metal alkoxide include silicic acid (Si (OH) ₄ ) that is a hydrolyzate of tetraethoxysilane and aluminum hydroxide (Al (OH) ₃ that is a hydrolyzate of tripropoxyaluminum. ) And the like. These can be used in combination of not only one type but also a plurality of types. Content of the metal alkoxide and its hydrolyzate in the said composition is 10-90 mass%, for example.

  The composition may further contain a hydroxyl group-containing polymer compound. Examples of the hydroxyl group-containing polymer compound include water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone and starch. The hydroxyl group-containing polymer compound is preferably polyvinyl alcohol from the viewpoint of barrier properties. These can be used in combination of not only one type but also a plurality of types. The content of the hydroxyl group-containing polymer compound in the composition is, for example, 10 to 90% by mass.

  The thickness of the gas barrier coating layer 13 is preferably 50 to 1000 nm, and preferably 100 to 500 nm. When the thickness of the gas barrier coating layer 13 is 50 nm or more, a sufficient gas barrier property tends to be obtained, and when it is 1000 nm or less, a sufficient flexibility tends to be maintained.

  FIG. 2 is a schematic cross-sectional view showing a light emitter protective film according to another embodiment of the present invention. In FIG. 2, the light emitter protection film 10 further includes an adhesion layer 17 in addition to the barrier film 16, the second base material layer 11 b, and the adhesive layer 15 in FIG. 1. In FIG. 2, the adhesion layer 17 is formed on the surface of the barrier film 16 opposite to the second substrate layer 11b (the surface on the first substrate layer 11a side).

  The adhesion layer 17 is provided in order to improve the adhesion between the illuminator protective film 10 and the illuminant layer, and a resin having a functional group such as a hydroxyl group in accordance with a material such as a sealing resin constituting the illuminant layer, or It is composed of a silane coupling agent or the like. Examples of the resin having a functional group such as a hydroxyl group include a urethane resin, an acrylic resin, an epoxy resin, and a polyester resin. The thickness of the adhesion layer 17 is, for example, about 1 to 500 nm, and preferably 1 to 100 nm.

  FIG. 3 is a schematic cross-sectional view showing a light emitter protective film according to another embodiment of the present invention. In FIG. 3, the light emitter protection film 10 further includes a coating layer 18 in addition to the barrier film 16, the second base material layer 11 b, and the adhesive layer 15 in FIG. 1. In FIG. 3, the coating layer 18 is formed on the surface opposite to the barrier film 16 of the second base material layer 11b. When the light emitter protection film 10 includes the coating layer 18, a light diffusion function can be obtained, and an antireflection function and a more excellent interference fringe prevention function can be obtained.

  The coating layer 18 may contain a binder resin and fine particles dispersed in the binder resin. Then, fine irregularities may be formed on the surface of the coating layer 18 by embedding the fine particles in the binder resin so that a part of the fine particles is exposed from the surface of the coating layer 18. Thus, by providing the coating layer 18 on the surface of the light emitter protection film 10, the generation of interference fringes such as Newton rings can be more sufficiently prevented.

  Although it does not specifically limit as binder resin, Resin excellent in optical transparency can be used. More specifically, for example, polyester resins, acrylic resins, acrylic urethane resins, polyester acrylate resins, polyurethane acrylate resins, urethane resins, epoxy resins, polycarbonate resins, polyamide resins, polyimide resins. Thermoplastic resins such as melamine resins and phenol resins, thermosetting resins, ionizing radiation curable resins, and the like can be used. Among these, it is desirable to use an acrylic resin excellent in light resistance and optical characteristics. These can be used in combination of not only one type but also a plurality of types.

  The average particle size of the fine particles is preferably from 0.1 to 30 μm, and more preferably from 0.5 to 10 μm. When the average particle size of the fine particles is 0.1 μm or more, an excellent interference fringe prevention function tends to be obtained, and when it is 30 μm or less, the transparency tends to be further improved.

  The content of the fine particles in the coating layer 18 is preferably 0.5 to 30% by mass, more preferably 3 to 10% by mass based on the total amount of the coating layer 18. When the content of the fine particles is 0.5% by mass or more, the light diffusion function and the effect of preventing the generation of interference fringes tend to be further improved, and when the content is 30% by mass or less, the reduction in luminance tends to be suppressed. There is.

  The luminous body protective film 10 can be suitably used as a protective film for a luminous body that can be deteriorated by contact with oxygen, water vapor, or the like. As said light-emitting body, fluorescent substance, such as a quantum dot, an electroluminescent light-emitting body, etc. are mentioned.

(Wavelength conversion sheet)
FIG. 4 is a schematic cross-sectional view of a wavelength conversion sheet according to an embodiment of the present invention. The wavelength conversion sheet is a sheet that can convert some wavelengths of light from the light source of the backlight unit for liquid crystal display. As shown in FIG. 4, the wavelength conversion sheet 20 of the present embodiment includes a first protective film, a phosphor layer 21 formed on the first protective film, and a first layer provided on the phosphor layer 21. The two protective films 22 are schematically configured. The wavelength conversion sheet 20 has a structure in which the phosphor layer 21 is encapsulated (that is, sealed) between the first protective film and the second protective film 22. In FIG. 4, the above-described phosphor protective film 10 is used as the first protective film, and the phosphor protective film 10 is disposed so as to face the barrier film 16 and the phosphor layer 21. On the other hand, for the second protective film 22, the above-described light emitter protective film 10 may be used, or another protective film may be used. Further, the wavelength conversion sheet 20 does not necessarily have to include the second protective film 22. That is, the wavelength conversion sheet 20 of the present embodiment includes the light emitter protective film 10 and the phosphor layer 21 formed on the surface of the light emitter protective film 10 on the barrier film 16 side.

  As described above, the phosphor protective film 10 includes the barrier film 16 on the phosphor layer 21 side, and the second base material layer 11b on the opposite side with the adhesive layer 15 interposed therebetween, thereby stably obtaining gas barrier properties. Can do. However, when the protective film has a defect in the barrier layer, the defect may become a gas intrusion path, and the generation of dark spots in the phosphor layer near the defect may not be suppressed. It is considered that the dark spot generation mechanism in the phosphor layer is dominated by gas intrusion in the thickness direction of the protective film from the surface (outside) of the protective film opposite to the phosphor layer. They think that it is not necessarily generated only by the above mechanism. The mechanism by which such dark spots occur is not always clear, but the present inventors consider as follows. FIG. 5 is a conceptual diagram showing a dark spot generation mechanism assumed in a wavelength conversion sheet having a defect in a barrier layer arranged on the phosphor layer side. In the wavelength conversion sheet 200 of FIG. 5, oxygen, water vapor, and the like in the atmosphere enter from the end face of the adhesive layer 150 of the light emitter protection film 100 and diffuse in the surface direction of the adhesive layer 150. When the phosphor protective film 100 has the defect 23 in the barrier layer 140, diffused oxygen, water vapor, or the like reaches the phosphor layer 210 through the defect 23. Thus, the deterioration of the phosphor progresses around the position of the defect 23 and appears as a dark spot 24 over time. When the defect 23 penetrates through the first base material layer 110a together with the barrier layer 140, it is considered that the progress of phosphor deterioration becomes remarkable and the dark spot 24 is easily visually recognized. That is, oxygen, water vapor, or the like passes through the defect 23 of the barrier film 160 having gas barrier properties from the end face of the adhesive layer 150, and the phosphor is deteriorated. Oxygen or water vapor in the atmosphere entered from the end face of the adhesive layer 150 as compared to the distance when the second base material layer 110b entered the thickness direction of the light emitter protective film 100 from the opposite side of the phosphor layer 210. Since the distance in the case was extremely large and the amount of intrusion was considered to be extremely small, it can be said that the generation of dark spots by the mechanism shown in FIG. 5 was surprising. According to the wavelength conversion sheet 20 of this embodiment, the phosphor protective film 10 has a defect in the barrier layer by using the phosphor protective film 10 as a protective film provided on the phosphor layer 21. Even if this occurs, the occurrence of dark spots can be suppressed.

  The phosphor layer 21 contains a resin and a phosphor. The thickness of the phosphor layer 21 is several tens to several hundreds μm. As the resin, for example, a photocurable resin or a thermosetting resin can be used. The phosphor layer 21 preferably includes two types of phosphors composed of quantum dots. Further, the phosphor layer 21 may be a laminate in which two or more phosphor layers containing one kind of phosphor and another kind of phosphor are laminated. Two types of phosphors having the same excitation wavelength are selected. The excitation wavelength is selected based on the wavelength of light emitted from the light source of the backlight unit. The fluorescent colors of the two types of phosphors are different from each other. When a blue light emitting diode (blue LED) is used as the light source, the fluorescent colors are red and green. The wavelength of each fluorescence and the wavelength of light emitted from the light source are selected based on the spectral characteristics of the color filter. The peak wavelength of fluorescence is, for example, 610 nm for red and 550 nm for green.

  Next, the particle structure of the phosphor will be described. As the phosphor, a core-shell type quantum dot having particularly good luminous efficiency is preferably used. The core-shell type quantum dot is obtained by covering a semiconductor crystal core as a light emitting portion with a shell as a protective film. For example, cadmium selenide (CdSe) can be used for the core and zinc sulfide (ZnS) can be used for the shell. The surface yield of CdSe particles is covered with ZnS having a large band gap, so that the quantum yield is improved. Further, the phosphor may be one in which the core is doubly covered with the first shell and the second shell. In this case, CdSe can be used for the core, zinc selenide (ZnSe) can be used for the first shell, and ZnS can be used for the second shell.

  The phosphor layer 21 may have a single layer configuration in which all the phosphors are dispersed in a single layer, and has a multilayer configuration in which each phosphor is separately dispersed in a plurality of layers and laminated. You may do it.

  Next, the manufacturing method of the wavelength conversion sheet 20 of this embodiment is demonstrated, referring FIG. It does not specifically limit as a formation method of the fluorescent substance layer 21, For example, the method described in Japanese translations of PCT publication No. 2013-544018 is mentioned. After the phosphor is dispersed in the binder resin, the prepared phosphor dispersion is applied on the barrier film 16 side of the first protective film (illuminator protective film 10), and then the second protective film 22 is pasted on the coated surface. In addition, the wavelength conversion sheet 20 can be manufactured by curing the phosphor layer 21. On the other hand, the phosphor dispersion liquid is applied on one surface of the second protective film 22, and the phosphor protective film 10 is bonded to the coated surface so that the barrier film 16 and the phosphor layer 21 face each other. The wavelength conversion sheet 20 can also be manufactured by curing the phosphor layer 21.

[Backlight unit]
By using the wavelength conversion sheet 20, a backlight unit is obtained. FIG. 6 is a schematic cross-sectional view of a backlight unit obtained using the wavelength conversion sheet 20. In FIG. 6, the backlight unit 30 includes a light source 32 and the wavelength conversion sheet 20, and the light emitter protection film 10 is disposed on the opposite side of the light source 32 with the phosphor layer 21 interposed therebetween. Specifically, in the backlight unit 30, the light guide plate 34 and the reflection plate 36 are arranged in this order on the surface of the wavelength conversion sheet 20 on the second protective film 22 side, and the light source 32 is disposed on the side of the light guide plate 34 ( It is arranged in the surface direction of the light guide plate 34.

The light guide plate 34 and the reflection plate 36 efficiently reflect and guide the light emitted from the light source 32, and a known material is used. As the light guide plate 34, for example, acrylic, polycarbonate, cycloolefin film, or the like is used. For example, the light source 32 is provided with a plurality of blue light emitting diode elements. The light emitting diode element may be a violet light emitting diode or a light emitting diode having a lower wavelength. Light emitted from the light source 32 is incident on the light guide plate 34 (D ₁ direction) is incident on the phosphor layer 21 with the reflection and refraction, etc. (D ₂ direction). The light that has passed through the phosphor layer 21 becomes white light by mixing the yellow light generated in the phosphor layer 21 with the light before passing through the phosphor layer 21.

[Electroluminescence light emitting unit]
FIG. 7 is a schematic sectional view of an electroluminescence light emitting unit according to an embodiment of the present invention. The electroluminescence light emitting unit 50 according to this embodiment includes an electroluminescence light emitter layer 56 and a light emitter protection film 10. The electroluminescence light emitting unit 50 includes, for example, a transparent electrode layer 54, an electroluminescence light emitter layer 56 provided on the transparent electrode layer 54, and a dielectric layer 58 provided on the electroluminescence light emitter layer 56. The electrode element including the back electrode layer 60 provided on the dielectric layer 58 is obtained by sandwiching and sealing between the first protective film and the second protective film 62. In the electroluminescence light emitting unit, the above-described light emitter protective film 10 is used as the first protective film. The electroluminescence light emitter layer 56 is formed on the barrier film 16 side of the light emitter protection film 10.

  Also in the electroluminescence light emitting unit, dark spots can be generated by the same mechanism as described for the wavelength conversion sheet. According to the electroluminescent light emitting unit 50 according to the present embodiment, the light emitter protective film 10 is used by using the light emitter protective film 10 as a protective film provided on the electrode element including the electroluminescent light emitter layer 56. Even if the barrier layer has a defect, generation of dark spots can be suppressed.

  Each electrode layer, electroluminescence light emitting layer, and dielectric layer can be formed using a known material by, for example, vapor deposition and sputtering.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited to these examples.

[Preparation of luminous body protective film]
Example 1
Acrylic polyol and tolylene diisocyanate are mixed so that the number of NCO groups of tolylene diisocyanate is equal to the number of OH groups of acrylic polyol, and ethyl acetate is added so that the total solid content becomes 5% by mass. Diluted. Β- (3,4 epoxy cyclohexyl) trimethoxysilane is further added to the diluted liquid mixture so as to be 5% by mass with respect to the total solid content, and these are mixed to obtain an anchor coat layer composition. Produced.

  On one surface of a biaxially stretched polyethylene terephthalate film (first base material layer, thickness: 25 μm), the anchor coat layer composition is applied by a bar coating method, and dried and cured at 100 ° C. for 1 minute to obtain a thickness. An anchor coat layer having a thickness of 50 nm was formed.

Using an electron beam heating vacuum deposition apparatus, a silicon oxide material (SiO, manufactured by Canon Optron Co., Ltd.) is evaporated by electron beam heating under a pressure of 1.5 × 10 ⁻² Pa. A 30 nm thick SiO _x film (first inorganic thin film layer) was formed. In addition, the acceleration voltage in vapor deposition was 40 kV, and the emission current was 0.2 A.

  Next, 10.4 parts by mass of tetraethoxysilane and 89.6 parts by mass of hydrochloric acid (concentration: 0.1 N) were mixed, and the mixture was stirred for 30 minutes to obtain a hydrolyzed solution of tetraethoxysilane. On the other hand, polyvinyl alcohol was dissolved in a mixed solvent of water / isopropyl alcohol (water / isopropyl alcohol (mass ratio) = 90: 10) to obtain a 3% by mass polyvinyl alcohol solution. 60 parts by mass of a tetraethoxysilane hydrolysis solution and 40 parts by mass of a polyvinyl alcohol solution were mixed to obtain a gas barrier coating composition.

  On the first inorganic thin film layer, the gas barrier coating layer composition was applied and dried to form a first gas barrier coating layer having a thickness of 300 nm. Further, a second inorganic thin film layer having a thickness of 30 nm is formed on the first gas barrier coating layer in the same manner as described above, and a second gas barrier coating layer having a thickness of 300 nm is formed on the second inorganic thin film layer. Formed. As described above, the first base layer, the anchor coat layer, the first inorganic thin film layer, the first gas barrier coating layer, the second inorganic thin film layer, and the second gas barrier coating layer are laminated in this order. A film was obtained.

  The following adhesive A is applied on the surface of the second gas barrier coating layer of the obtained barrier film, and a biaxially stretched polyethylene terephthalate film (second base material layer, thickness: 25 μm) is applied to the adhesive A application surface. ) And aged at 50 ° C. for 2 days. As described above, the barrier film and the second base material layer were bonded together via an adhesive layer having a thickness of 5 μm. The adhesive A is an adhesive composition obtained by mixing a main agent made of an epoxy resin and a curing agent made of a polyamine resin.

  Next, 100 parts by mass of acrylic resin (trade name: Acaridic, manufactured by DIC) and silica particles (trade name: Tospearl 120, average particle) on the surface of the second base material layer on which the barrier film is not bonded. A composition consisting of 20 parts by mass (diameter: 2.0 μm, manufactured by Momentive Performance Materials) was applied. The coating film was heated to cure the acrylic resin, thereby forming a coating layer having a thickness of 3 μm.

  Furthermore, an aqueous solution containing 3-aminopropyltriethoxysilane is applied on the surface of the barrier film on the first base layer side by a reverse gravure method, and heated at a temperature of 100 ° C. for 1 minute, thereby adhering to a thickness of 30 nm. A layer was formed. As described above, a light emitter protective film in which the adhesion layer, the barrier film, the adhesive layer, the second base material layer, and the coating layer were laminated in this order was obtained.

(Comparative Example 1)
In the same manner as in Example 1, except that the following adhesive B was used instead of the adhesive A as the adhesive used when the barrier film and the second base material layer were bonded to each other. A phosphor protective film was obtained.

[Evaluation of phosphor protective film]
(Oxygen permeability of adhesive layer)
Adhesives A to B used in Examples and Comparative Examples were each applied onto a CPP (unstretched polypropylene film) having a thickness of 70 μm, and a CPP having a thickness of 70 μm was bonded to the application surface of the adhesive. Aging was performed at 5 ° C. for 5 days. As described above, an oxygen permeability measurement sample (laminated body) was obtained, in which a CPP having a thickness of 70 μm, an adhesive layer having a thickness of 5 μm, and a CPP having a thickness of 70 μm were laminated in this order. The obtained sample was placed in a differential pressure type gas permeability measuring apparatus (GTR-30X, manufactured by GTR Tech Co., Ltd.), and the temperature was 40 ° C. and the relative humidity was 0 according to the method described in JIS K7126-1 (Appendix 1). The oxygen permeability of the above sample was measured by a differential pressure method at a differential pressure of 101 kPa (1 atm) with oxygen as a test gas in a% environment. Table 1 shows the measurement results of oxygen permeability. By using a film having an oxygen permeability higher than that of the adhesive layer (for example, an oxygen permeability higher than 1000 cm ³ / (m ² · day · atm)) as the film bonded with the adhesive, the above sample is used. This measurement result can be regarded as the oxygen permeability of the adhesive layer. In the above measurement method, as a film that is bonded by an adhesive, since it is used CPP oxygen permeability ^{2500cm 3 / (m 2 · day} · atm), 2500cm 3 / (m 2 · day · atm ) The measurement results of oxygen permeability of the following samples can be regarded as oxygen permeability of the adhesive layer.

In addition, the detail of the adhesive agent described in Table 1 is as follows.
Adhesive A: Maxive manufactured by Mitsubishi Gas Chemical Co., Inc., mixing ratio (epoxy resin main agent / amine curing agent / methanol / ethyl acetate = 1/3/3/6 (mass ratio))
Adhesive B: Made by Seiden Chemical Co., Ltd., blending ratio (polyol resin main agent X-313-405S / polyisocyanate hardener K-341 / toluene = 25 / 0.34 / 31.25 (mass ratio)).

[Production of wavelength conversion sheet]
Concentration adjustment by dispersing a phosphor (trade name: CdSe / ZnS 530, manufactured by SIGMA-ALDRICH) having a core / shell structure in which cadmium selenide (CdSe) particles are coated with zinc sulfide (ZnS) in a solvent. A phosphor dispersion liquid was prepared. The phosphor dispersion was mixed with an epoxy photosensitive resin to obtain a phosphor composition. On the surface of the phosphor protective film obtained in Examples and Comparative Examples on the barrier film side, the phosphor composition was applied to form a phosphor layer having a thickness of 100 μm.

  On the phosphor layer, a second phosphor protective film obtained in the same Example and Comparative Example was further placed and laminated so that the barrier film faced the phosphor layer side, and then fluorescent by ultraviolet irradiation. By curing the body layer (photosensitive resin), a wavelength conversion sheet using the phosphor protective film prepared in Examples and Comparative Examples was obtained.

[Evaluation of wavelength conversion sheet]
(Needle hole evaluation)
In the production of the wavelength conversion sheet, as a barrier film of one of the light emitter protective films, a hole having a diameter of about 30 to 100 μm and penetrating the barrier layer and the first base material layer is provided by inserting a needle from the barrier layer side. The wavelength conversion sheet for dark spot evaluation with respect to each of Examples and Comparative Examples was prepared using the barrier film. The hole is a pseudo reproduction of the hole due to splash when the inorganic thin film layer is formed by vapor deposition. The obtained wavelength conversion sheet for dark spot evaluation was exposed to an environment having a temperature of 85 ° C. and a relative humidity of 0% RH. For the wavelength conversion sheet for dark spot evaluation after 72 hours exposure, irradiate blue light from the side of the phosphor protective film without holes, and visually confirm the transmitted light from the side of the phosphor protective film with holes. The presence or absence of black spot-like defects (dark spots) was evaluated according to the following criteria. Table 2 shows the evaluation results of dark spots around the holes, along with the major axis a and minor axis b of the holes provided in the barrier film.
A: After 72 hours of exposure, no non-luminescent spot (dark spot) having a diameter larger than the needle hole centered on the needle hole was generated.
B: After exposure for 72 hours, a non-luminescent point (dark spot) having a diameter larger than the needle hole centered on the needle hole was generated.

In Example 1 in which the oxygen permeability of the adhesive layer was 100 cm ³ / (m ² · day · atm) or less, the presence of dark spots was not confirmed even after exposure for 72 hours in a high temperature environment. In contrast, in Comparative Example 1 in which the oxygen permeability of the adhesive layer exceeded 2000 cm ³ / (m ² · day · atm), dark spots were confirmed after 72 hours of exposure.

(Dark spot evaluation)
Wavelength conversion sheets using the phosphor protective films obtained in Examples and Comparative Examples were cut to 60 cm × 34 cm (corresponding to a 27-inch monitor) and exposed for 72 hours in an environment at a temperature of 85 ° C. and a relative humidity of 0%. did. After the exposure, UV light was irradiated, and the number of dark spots (including minute dark spots) in the central 5 cm × 5 cm range of the wavelength conversion sheet after cutting was visually counted. Table 3 shows the number of dark spots.

  From Table 3, dark spots were 40 or more in Comparative Example 1 where the oxygen permeability of the adhesive layer was high, and many dark spots were generated as compared with Example 1.

DESCRIPTION OF SYMBOLS 10 ... Luminescent body protective film, 11a ... 1st base material layer, 11b ... 2nd base material layer, 12 ... Inorganic thin film layer, 13 ... Gas barrier property coating layer, 14 ... Barrier layer, 15 ... Adhesive layer, 16 ... Barrier film 20 ... wavelength conversion sheet, 21 ... phosphor layer, 22 ... second protective film, 23 ... defect, 24 ... dark spot, 30 ... backlight unit, 50 ... electroluminescence light emitting unit.

Claims (9)

A barrier film comprising a first substrate layer and a barrier layer formed on the first substrate layer, and a second substrate layer,
The second base material layer is bonded to the barrier layer side surface of the barrier film via an adhesive layer,
The phosphor protective film, wherein the adhesive layer has an oxygen permeability of 100 cm ³ / (m ² · day · atm) or less at a thickness of 5 μm. The first base layer is a polyethylene terephthalate film or a polyethylene naphthalate film,
The light emitter protective film according to claim 1, wherein the second base material layer is a polyethylene terephthalate film or a polyethylene naphthalate film.   The light emitter protective film according to claim 1, wherein the adhesive layer is formed of an adhesive containing an epoxy resin.   The light emitter protective film according to any one of claims 1 to 3, wherein the barrier layer has an inorganic thin film layer and a gas barrier coating layer.   The light emitter protective film according to claim 1, further comprising an adhesion layer formed on a surface of the barrier film opposite to the second base material layer.   The light emitter protective film according to claim 1, further comprising a coating layer formed on a surface of the second base material layer opposite to the barrier film.   The light emitter protective film according to claim 6, wherein the coating layer contains a binder resin and fine particles dispersed in the binder resin.   A wavelength conversion sheet comprising: the light emitter protective film according to claim 1; and a phosphor layer formed on the barrier film side surface of the light emitter protective film. An electroluminescent light emitting unit comprising: the light emitter protective film according to any one of claims 1 to 7; and an electroluminescent light emitter layer formed on a surface of the light emitter protective film on the barrier film side. .

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