JP2008004502A - Dispersed electroluminescence element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersed EL element that is more excellent in flexibility than the dispersed EL element using the conventional sputtering ITO film, concretely, to provide a dispersed EL element that is formed on a thin or flexible transparent plastic film, and to provide its manufacturing method. <P>SOLUTION: The dispersed electroluminescence element is composed of a transparent coating layer reinforced at least with fibers and/or flake-like particles, a transparent conductive layer, a phosphor layer, a dielectric layer, and a rear-face electrode layer that are all successively formed on the base-film surface. The transparent coating layer reinforced with fibers and/or flake-like particles is peelable from the base-film surface. The transparent conductive layer is cured after executing compression treatment to a layer film formed by applying an application liquid for transparent conductive layer formation, which is mainly composed of conductive oxide particles and a binder, onto the surface of the transparent coating layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dispersive electroluminescent element obtained using a film with a transparent conductive layer in which a transparent conductive layer mainly composed of conductive oxide fine particles and a binder is formed, and a method for producing the same. The present invention relates to a distributed electroluminescence element applied as a light emitting element incorporated in a key input component of various devices such as a telephone and a method for manufacturing the same.

A dispersive electroluminescence element (hereinafter sometimes abbreviated as “dispersion EL element”) is a light-emitting element driven by an alternating voltage, and used for backlights of liquid crystal displays such as mobile phones and remote controllers. However, in recent years, an attempt has been made to apply to a light emitting element incorporated in a key input component (keypad) of various devices as a new application.

Examples of such devices include mobile information terminals such as mobile phones, remote controllers, PDAs (Personal Digital Assistance) and laptop PCs, and the light emitting elements facilitate key input operations in dark places such as at night. It is used for the purpose.
Conventionally, a light emitting diode (LED) has been applied as a light emitting element of the key input component (keypad). However, the LED is a point light source, the brightness of the keypad part is uneven, and the appearance is generally poor. Blue light-emitting colors are preferred, but LEDs have a problem of high cost and high power consumption compared to the dispersion type EL element. Therefore, the dispersion type EL element is used instead of the LED. The movement to do is conspicuous.

  As a manufacturing method of such a dispersion type EL element, the following method is generally widely adopted. That is, a plastic film (hereinafter referred to as “sputtering ITO film”) on which a transparent conductive layer of indium tin oxide (hereinafter abbreviated as “ITO”) is formed using a physical film forming method such as sputtering or ion plating. This is a method of forming a phosphor layer, a dielectric layer, and a back electrode layer sequentially by screen printing or the like.

  Here, the paste used for forming (printing) the phosphor layer, the dielectric layer, and the back electrode layer is formed by dispersing phosphor particles, dielectric particles, and conductive particles in a solvent containing a binder, respectively. For example, a commercially available paste can be used.

In addition, the sputtering ITO film has an ITO single layer, which is an inorganic component, on a transparent plastic film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), and has a thickness of about 20 to 50 nm by the physical film forming method. The surface resistance value is about 100 to 300Ω / □ (ohms per square) and low resistance is obtained.
However, since the ITO layer is a thin film of an inorganic component and is extremely brittle, it is easy for microcracks (breaks) to occur in the film, and in order to prevent this, the plastic film as the base material must have sufficient strength and rigidity. The thickness is at least 50 μm or more, usually 75 μm or more.

  Currently, a PET film is widely used as the base film of the sputtering ITO film. However, if the thickness is less than 50 μm, the flexibility of the film is too high, and the ITO film is handled during handling. For example, a thin sputtered ITO film having a thickness of 25 μm or the like has not been put into practical use because the layer easily cracks and the conductivity of the film is remarkably impaired. Moreover, even if the soft base film such as urethane has a film thickness of 75 μm or more, cracks are easily generated when a sputtering ITO layer is formed, and it has not been put into practical use.

By the way, as a characteristic required when a distributed EL element is applied to the keypad, for example, as disclosed in Patent Document 1, in addition to the above-described uniformity of luminance and low power consumption, the keypad is operated. It is important to have a good click feeling.
In order to prevent the click feeling from being impaired by incorporating a dispersion type EL element into this keypad, it is necessary to sufficiently increase the flexibility of the dispersion type EL element itself, that is, to reduce the thickness of the element as much as possible. Alternatively, it is necessary to use a flexible base film.

  However, when a dispersion type EL element is produced using the above-mentioned sputtered ITO film, it is necessary to increase the rigidity of the film to be at least 50 μm thick as a base film to prevent cracks in the ITO layer. Therefore, when applied to the keypad, there is a problem that the click feeling of key operation is not sufficiently good.

Further, as another problem different from the above, for example, Patent Document 4 points out the destruction / failure of LCD (liquid crystal) parts and the like due to static electricity generated at the time of key input of a cellular phone. For this reason, the same problem may occur in the key input component of the dispersion type EL element. As a countermeasure, for example, a method of releasing the static electricity by forming a transparent conductive layer on the outer surface of the dispersion type EL element can be cited. However, since the base film for the keypad has high flexibility as described above, the conventional sputtering ITO film cannot be applied. Further, it has not been easy to inexpensively form a transparent conductive film satisfying the durability (spot durability), transparency, and conductivity required for the keypad on the outer surface of the dispersion type EL element.
JP 2001-238331 A JP-A-4-237909 JP-A-5-036314 JP 2002-232537 A

  The present invention has been made in view of such conventional circumstances, and is a dispersion type EL element that is more flexible than a conventional dispersion type EL element using a sputtering ITO film, specifically thin or flexible. It is an object of the present invention to provide a dispersion type EL element formed on a transparent plastic film and a method for manufacturing the same.

  In order to achieve the above object, the present inventors have made various studies, and as a result, at least a transparent coating layer, a transparent conductive layer, a phosphor layer, a dielectric layer, and a back electrode layer sequentially formed on the surface of the base film. In the dispersion type electroluminescent device comprising the transparent coating layer, the transparent coating layer is a coating layer reinforced with visible light transmitting fibers and / or flaky particles, and can be peeled off from the base film. The transparent conductive layer is mainly composed of conductive oxide fine particles and a binder matrix by using a method of coating and forming on the base film using a coating liquid for forming a transparent conductive layer instead of a conventional physical film formation method. Because it is a component, cracks easily occur in the transparent conductive layer during handling of the film with the transparent conductive layer. By suppressing the damage and compressing the coating layer obtained by applying the coating liquid for forming the transparent conductive layer, the packing density of the conductive fine particles in the transparent conductive layer is increased and light scattering is reduced. In addition to improving the optical characteristics of the film, the conductivity is greatly improved, and a dispersive EL element that is superior in conductivity and flexibility to a dispersive EL element using a conventional sputtering ITO film is provided at low cost. In addition, when the distributed EL element is applied to a keypad of a cellular phone or the like, it is possible to obtain a good click feeling of key operation without performing a special structure or device on the keypad. As a result, the present invention has been achieved.

That is, the dispersive electroluminescent device according to the present invention is a dispersion formed of at least a transparent coating layer, a transparent conductive layer, a phosphor layer, a dielectric layer, and a back electrode layer, which are sequentially formed on the surface of the base film. The transparent coating layer is formed on the surface of the base film using a transparent resin and a coating liquid for forming a transparent coating layer mainly composed of visible light transmissive fibers and / or flaky particles. A coating layer reinforced with fibers and / or flaky particles, which can be peeled off from the surface of the base film, and the transparent conductive layer is a coating solution for forming a transparent conductive layer mainly composed of conductive oxide particles and a binder. The coating layer formed by coating the surface of the transparent coating layer with a compression treatment and then cured It is characterized in that those allowed.
In another dispersion type electroluminescent device according to the present invention, a second transparent conductive layer is further formed between the transparent base film and the transparent coating layer, and the second transparent conductive layer is conductively oxidized. A coating solution for forming a transparent conductive layer mainly composed of particle particles and a binder is applied on the surface of the base film and cured, or the coating solution for forming a transparent conductive layer is formed on the surface of the base film. The second coating layer formed by coating is cured after being subjected to compression treatment, and the thickness of the transparent coating layer is 50 μm or less, and the conductive property The oxide fine particles contain at least one of indium oxide, tin oxide, and zinc oxide as a main component, and the conductive oxide has the indium oxide as a main component. The particles are indium tin oxide fine particles, the binder has crosslinkability, and the transparent conductive layer and the second transparent conductive layer have organic solvent resistance. The compression treatment is performed by rolling a metal roll, and the base film is peeled and removed at the interface with the transparent coating layer or the second transparent conductive layer. The distributed electroluminescence element described above is applied as a light emitting element incorporated in a key input component of a device, and the device is a mobile phone, a remote controller, or a portable information terminal Is.

Furthermore, in the method for manufacturing a dispersion type electroluminescent device according to the present invention, at least a transparent coating layer, a transparent conductive layer, a phosphor layer, a dielectric layer, and a back electrode layer are sequentially formed on the surface of the base film. Dispersion type electroluminescent device manufacturing method comprising fibers and / or flakes formed using a transparent resin and a coating liquid for forming a transparent coating layer mainly composed of visible light transmissive fibers and / or flaky particles A coating layer is formed on the surface of the transparent coating layer reinforced with particle-like particles using a coating liquid for forming a transparent conductive layer mainly composed of conductive oxide fine particles and a binder, and then the transparent coating layer and the coating layer A transparent conductive layer is formed by applying a compression treatment to the base film on which is formed and then curing the base film. That.
Next, another dispersion type electroluminescent device manufacturing method according to the present invention includes at least a transparent coating layer, a transparent conductive layer, a phosphor layer, a dielectric layer, and a back electrode layer on the surface of the base film. A method for producing a dispersion type electroluminescent device that is sequentially formed, wherein a coating solution for forming a transparent conductive layer mainly composed of conductive oxide fine particles and a binder is applied on the surface of the base film and cured, or A second transparent conductive layer is formed by applying a compression treatment to the second applied layer formed by coating and then curing, and transparent resin and visible light transmission are formed on the surface of the second transparent conductive layer. A transparent coating layer reinforced with fibers and / or flaky particles using a coating solution for forming a transparent coating layer mainly composed of porous fibers and / or flaky particles And forming a coating layer on the surface of the transparent coating layer by using a coating solution for forming a transparent conductive layer mainly composed of conductive oxide fine particles and a binder, and then forming the base film and the second transparent layer. The conductive layer, the transparent coating layer and the coating layer are subjected to compression treatment and then cured to form a transparent conductive layer.

  Moreover, the manufacturing method of the other dispersion-type electroluminescent element which concerns on this invention is the interface with the said transparent coating layer or the said 2nd transparent conductive layer further after the manufacturing process of the said dispersion-type electroluminescence element of the said description. The compression treatment is performed by rolling a metal roll, and the rolling treatment has a linear pressure of 29.4 to 784 N / mm (30 to 800 kgf / cm). The rolling process is characterized in that the linear pressure is 98 to 490 N / mm (100 to 500 kgf / cm).

  According to the present invention, there is provided a dispersive electroluminescence device having at least a base film and a transparent coating layer, a transparent conductive layer, a phosphor layer, a dielectric layer, and a back electrode layer sequentially formed on the base film, The transparent coating layer is a coating layer reinforced with visible light transmissive fibers and / or flaky particles, and can be peeled off from the base film, and the transparent conductive layer is not a conventional physical film-forming method. By using a method of coating and forming on the base film using a coating liquid for forming a transparent conductive layer, the transparent conductive layer is mainly composed of conductive oxide fine particles and a binder matrix. Cracks in the transparent conductive layer easily during the handling of the attached film, suppressing the significant loss of conductivity, In addition, by compressing the coating layer obtained by coating the coating liquid for forming the transparent conductive layer, the packing density of the conductive fine particles in the transparent conductive layer is increased, and light scattering is decreased to reduce the optical properties of the film. In addition to significantly improving the conductivity, it is possible to provide a low cost dispersion type EL element that is more conductive and flexible than the conventional dispersion type EL element using a sputtering ITO film, In addition, when the above distributed EL element is applied to a keypad of a mobile phone or the like, it becomes possible to obtain a good click feeling of key operation without performing a special structure or device on the keypad. Useful.

  As shown in FIG. 1, the conventional dispersion type electroluminescent device has at least a transparent conductive layer 2, a phosphor layer 3, a dielectric layer 4, and a back electrode layer 5 sequentially formed on a transparent plastic film 1. In addition, in application to an actual device, as shown in FIG. 2, it is common to further form and use a current collecting electrode 6 such as silver or an insulating protective layer 7.

  On the other hand, the dispersive electroluminescent device according to the present invention has a transparent coating layer 9, a transparent conductive layer 2, a phosphor layer 3, and a dielectric layer 4 which are sequentially formed on a base film 8 as shown in FIG. 3. In addition, at least the back electrode layer 5 is provided, and in application to an actual device, as shown in FIG. 4, the base film is used by being peeled and removed at the interface with the transparent coating layer. (Although not shown in FIG. 4, it is common to further form and use a collector electrode such as silver or an insulating protective layer as in FIG. 2.)

The base film used in the present invention preferably has a thickness of 50 μm or more. If the thickness of the base film is less than 50 μm, the rigidity of the film decreases, handling in the manufacturing process of the above-described dispersion type EL element, warping of the substrate (curl), phosphor layer, dielectric layer, back electrode layer Problems such as printability, etc. are likely to occur. Conversely, if it is 150 μm or more, the base film becomes hard and difficult to handle, and at the same time, it is not preferable in terms of cost.
For this reason, when both are considered, the thickness of the base film is optimally 75 μm or more and 125 μm or less.
The base film is not required to be transparent, and may be peelable from the transparent coating layer. The material is not particularly limited, and various plastics can be used. Specifically, plastics such as polycarbonate (PC), polyethersulfone (PES), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), nylon, polyethersulfone (PES), and polyimide (PI) should be used. Can do. Among these, a PET film is preferable from the viewpoints of being inexpensive, excellent in strength, and having flexibility.

  Here, the role of the base film is to facilitate handling in the manufacturing process of the dispersion-type EL element of the present invention, and to warp the substrate in the stacking process of the phosphor layer, dielectric layer, back electrode layer, etc. The function of preventing curling, the function of protecting the dispersed EL element during transportation and handling, and the function of uniformly printing the transparent conductive layer, the phosphor layer, the dielectric layer, the back electrode layer, etc. Using a suction stage with a large number of small-diameter holes, the hole part is decompressed and fixed to the film. However, if the film as the base material is thin, the film in the hole part is deformed by the decompression, resulting in a dent. And a mark of the dent is formed on the printed film).

The transparent coating layer used in the present invention is formed on a base film using a coating solution for forming a transparent coating layer mainly composed of a transparent resin and visible light transmissive fibers and / or flaky particles. The thickness can be freely set, but the thickness is preferably 1 μm or more and 50 μm or less. When the thickness of the transparent coating layer exceeds 50 μm, the rigidity becomes high, and when it is incorporated in the keypad as a dispersion type EL element, it is difficult to obtain a good click feeling.
Further, when the thickness of the transparent coating layer is preferably 25 μm or less, more preferably 15 μm or less, and even more preferably 5 μm or less, it becomes possible to obtain a better click feeling, and the total thickness of the dispersion type EL element. Can be made as thin as 100 μm or less, for example, which is also preferable in terms of increasing the degree of freedom in device design. Since the transparent coating layer of the present invention is a coating layer reinforced with visible light transmissive fibers and / or flaky particles, the strength of the transparent coating layer can be maintained sufficiently high even if the thickness of the transparent coating layer is reduced. Have.

Since the transparent coating layer finally becomes the outermost surface of the dispersion-type EL element, it is necessary to electrically insulate the transparent conductive layer. However, if the thickness is less than 1 μm, there is a possibility that sufficient insulation cannot be achieved. It is not preferable.
Furthermore, the material of the transparent coating layer (transparent resin) is not particularly limited as long as it has a peelability from the base film and a transparent conductive layer can be formed thereon. For example, a thermoplastic resin, a thermosetting resin, Various resins such as an ultraviolet curable resin can be used. Specifically, resins such as urethane, epoxy, polyester, and fluorine resin can be used. Among these, urethane-based and fluorine-based resins are preferable from the viewpoints of being inexpensive, excellent in transparency, strength, and flexibility.

Visible light transmissive fibers (including needles, rods, and whiskers) used to reinforce the transparent coating layer are visible light transmissive, and various inorganic fibers or fibers can be used as long as the fiber thickness is about 2 to 3 μm or less. Organic fiber (plastic fiber) is applicable. For example, silica fibers, titania fibers, alumina fibers, potassium titanate fibers, aluminum borate fibers, etc. can be applied to inorganic fibers, and polyester fibers, nylon fibers, aramid fibers, etc. can be applied to organic fibers, but are not limited thereto. .
Visible light permeable flaky particles (including plate-like particles) used for strengthening the transparent coating layer are visible light permeable and have a thickness of about 2 to 3 μm or less. Plastic) flaky particles are applicable. For example, in the case of inorganic flaky particles, there are flaky particles such as silica, titania and alumina, and clay such as calcined kaolin.
The fibers and flaky particles have the effect of reinforcing the transparent coating layer in a state dispersed in a transparent resin (binder matrix). In order to improve the strength, the adhesive strength between the fibers and flaky particles and the transparent resin is increased. Since it is necessary to raise, it is preferable to perform the adhesive improvement process (a coupling agent process, a plasma process, etc.) to the surface of a fiber or flaky particle | grains as needed. As the coupling agent in the coupling agent treatment, for example, various coupling agents such as silicon and titanium can be applied. Examples of the silicon coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, and the like, and may be appropriately selected depending on the type of transparent resin to be used. It is not limited to these.

  Thus, according to the present invention, the thickness of the transparent coating layer can be set very thin, and if the material is appropriately selected, it is possible to impart good flexibility according to the application. .

In the dispersion type EL device according to the present invention, as shown in FIG. 5, a second transparent conductive layer 10 can be further formed between the base film 8 and the transparent coating layer 9. (In application to an actual device, the base film is used after being peeled and removed at the interface with the second transparent conductive layer 10.)
Since the second transparent conductive layer is for the purpose of preventing various harmful effects due to static electricity, it may be much higher than the resistance value of the above-mentioned transparent conductive layer applied as an electrode of the dispersion type EL element. The value is preferably about 1M (1 × 10 ⁶ ) Ω / □ or less.
The second transparent conductive layer is formed by applying and curing on a base film using a coating liquid for forming a transparent conductive layer in which conductive oxide fine particles are dispersed in a solvent containing a binder component, or The transparent conductive layer forming coating solution is applied onto a base film to form a second coating layer, and then the second coating layer is compressed and then cured, and dispersed. From the viewpoint of preventing luminance reduction of the type EL element as much as possible, it is preferable to have high transmittance. Therefore, the film thickness is preferably 3 μm or less, and more preferably 1 μm or less.
The material of the binder used for the second transparent conductive layer is not particularly limited as long as it has releasability from the base film and a transparent coating layer can be formed thereon, and various resins can be used. Specifically, resins such as urethane, epoxy, polyester, and fluorine resin can be used. Among these, urethane-based resins are preferable from the viewpoints of being inexpensive, excellent in transparency, strength, and flexibility.

Formation of a transparent conductive layer mainly composed of conductive oxide fine particles and a binder matrix on the transparent coating layer is performed by dispersing the conductive oxide fine particles in a solvent containing a binder component on the surface of the transparent coating layer. After applying and drying using the coating liquid for forming a transparent conductive layer, the base film on which the transparent coating layer is formed is subjected to compression treatment, and then the binder component is cured.
In addition, in the film (coating layer) before compression treatment obtained by applying and drying the coating liquid for forming the transparent conductive layer, many fine voids (micro voids) are formed between the conductive fine particles and the binder matrix. It is the state that was done. The above-mentioned voids occur because the amount of the binder component in the coating liquid for forming the transparent conductive layer of the present invention is small (for example, when conductive fine particles / binder component = 90/10), and the transparent conductive layer is formed. By simply applying and drying the coating liquid for coating, it is difficult to finely fill the conductive fine particles, and a considerable gap is formed between the conductive fine particles, but the binder component cannot completely fill it. is doing.
Here, as the compression treatment, for example, a base film having a transparent coating layer coated and dried with a coating liquid for forming a transparent conductive layer may be rolled with a steel roll. In the present invention, a dispersion type EL element having a structure having a transparent conductive layer rolled on an extremely thin transparent coating layer is finally obtained. In the rolling process, the thick base film is rolled together. Therefore, it is possible to apply a relatively high rolling pressure. The rolling pressure of the steel roll in this case is preferably a linear pressure: 29.4 to 784 N / mm (30 to 800 kgf / cm), more preferably 98 to 490 N / mm (100 to 500 kgf / cm), 196 to 294 N / mm. (200 to 300 kgf / cm) is more preferable. If the linear pressure is less than 29.4 N / mm (30 kgf / cm), the effect of improving the resistance value of the transparent conductive layer by the rolling treatment is insufficient. If the linear pressure exceeds 784 N / mm (800 kgf / cm), rolling equipment This is because the base film and the transparent coating layer may be distorted at the same time as the size of the film increases. Considering the balance between the price of the rolling equipment and the characteristics (transmissivity, haze, resistance value) of the transparent conductive layer by the rolling treatment, it may be appropriately set within the range of 98 to 490 N / mm (100 to 500 kgf / cm). desirable.
The rolling pressure (N / mm ² ) in the rolling treatment of the steel roll is a value obtained by dividing the linear pressure by the nip width (width crushed by the steel roll). Although the said nip width | variety is based also on the diameter and linear pressure of a steel roll, if it is a diameter of about 150 mm, it will be about 0.7-2 mm.
The packing density of the conductive fine particles in the transparent conductive film layer by the rolling treatment is 50 to 80 vol% (preferably from a low value of 45 vol% or less, for example), although it depends on the linear pressure, as compared with the case where the rolling treatment is not performed. Can be increased to about 55 to 80%). A packing density exceeding 80 vol% seems to be difficult to achieve in view of the presence of the binder component contained in the coating liquid for forming the transparent conductive layer and the physical filling structure of the conductive fine particles.
When the rolling process is performed, the voids present in the film are crushed and disappeared, and the packing density of the conductive fine particles in the transparent conductive layer is increased, so that the scattering of light is reduced and the optical characteristics of the film are improved. In addition to improving, the conductivity can be greatly increased.

  The transparent coating layer may be subjected to an easy adhesion treatment, specifically, a plasma treatment, a corona discharge treatment, a short-wavelength ultraviolet irradiation treatment, etc. in advance in order to increase the adhesion with the transparent conductive layer. it can.

The conductive oxide fine particles used in the coating liquid for forming the transparent conductive layer include conductive oxide fine particles mainly composed of at least one of indium oxide, tin oxide, and zinc oxide. For example, indium tin Oxide (ITO) fine particles, indium zinc oxide (IZO) fine particles, indium-tungsten oxide (IWO) fine particles, indium-titanium oxide (ITiO) fine particles, indium zirconium oxide fine particles, tin antimony oxide (ATO) fine particles , Fluorine tin oxide (FTO) fine particles, aluminum zinc oxide (AZO) fine particles, gallium zinc oxide (GZO) fine particles, etc., but not limited thereto, as long as they have transparency and conductivity. .
However, ITO is the most preferable because it has both high visible light transmittance and excellent conductivity.

The average particle size of the conductive oxide fine particles is preferably 1 to 500 nm, and more preferably 5 to 100 nm. When the average particle size is less than 1 nm, it is difficult to produce a coating liquid for forming a transparent conductive layer, and the resistance value of the obtained transparent conductive layer is increased. On the other hand, if it exceeds 500 nm, the conductive oxide fine particles are likely to settle in the coating liquid for forming the transparent conductive layer and are not easily handled, and at the same time, the transparent conductive layer can simultaneously achieve high transmittance and low resistance. Because it becomes difficult.
Further, the thickness of 5 to 100 nm is more preferable because the characteristics (transmittance, resistance value) of the transparent conductive layer and the stability of the coating liquid for forming the transparent conductive layer (precipitation of the conductive fine particles) can be balanced. Because it becomes.
The average particle diameter of the conductive oxide fine particles is a value observed with a transmission electron microscope (TEM).

  The binder component of the coating liquid for forming the transparent conductive layer is a function of bonding conductive oxide fine particles to increase the conductivity and strength of the film, a function of increasing the adhesion between the transparent coating layer and the transparent conductive layer, and a dispersion type. Has the function of imparting solvent resistance to prevent deterioration of the transparent conductive layer by organic solvents contained in various printing pastes used for forming phosphor layers, dielectric layers, back electrode layers, etc. in the EL device manufacturing process ing. As the binder, an organic and / or inorganic binder can be used, and the transparent coating layer to which the coating liquid for forming the transparent conductive layer is applied, the film forming conditions of the transparent conductive layer, etc. are considered so as to satisfy the above role. Can be selected as appropriate.

  For the organic binder, thermoplastic resins such as acrylic resins and polyester resins can also be applied, but generally it is preferable to have solvent resistance, and for that purpose, it is necessary to be a crosslinkable resin, It can be selected from thermosetting resins, room temperature curable resins, ultraviolet curable resins, electron beam curable resins, and the like. For example, epoxy resins and fluorine resins as thermosetting resins, two-part epoxy resins and urethane resins as room temperature curable resins, and resins containing various oligomers, monomers, and photoinitiators as ultraviolet curable resins Examples of the electron beam curable resin include resins containing various oligomers and monomers, but are not limited to these resins.

  Examples of the inorganic binder include binders mainly composed of silica sol, alumina sol, zirconia sol, titania sol and the like. For example, the silica sol may be a polymer obtained by hydrolyzing an orthoalkyl silicate by adding water or an acid catalyst to advance dehydration condensation polymerization, or a commercially available alkyl silicate solution which has already been polymerized to a tetramer to a pentamer. Further, a polymer obtained by further proceeding hydrolysis and dehydration condensation polymerization can be used.

  If the dehydration condensation polymerization proceeds too much, the solution viscosity increases and eventually solidifies. Therefore, the degree of dehydration condensation polymerization is adjusted to be equal to or lower than the upper limit viscosity that can be applied on the transparent substrate. However, the degree of dehydration condensation polymerization is not particularly limited as long as it is a level equal to or lower than the above upper limit viscosity, but considering the film strength, weather resistance and the like, a weight average molecular weight of about 500 to 50,000 is preferable. This alkylsilicate hydrolyzed polymer (silica sol) undergoes almost complete dehydration condensation reaction (crosslinking reaction) upon heating after application and drying of the coating solution for forming the transparent conductive layer, resulting in a hard silicate binder matrix (silicon oxide). A binder matrix containing as a main component. The dehydration-condensation reaction starts immediately after drying the film, and as the time elapses, the conductive oxide fine particles are hardened so that they cannot move. It is necessary to carry out as soon as possible after applying and drying the conductive layer forming coating solution.

  An organic-inorganic hybrid binder can also be used as the binder. For example, a binder obtained by partially modifying the above-described silica sol with an organic functional group and a binder mainly composed of various coupling agents such as a silicon coupling agent can be given.

  The transparent conductive layer using the inorganic binder or the organic-inorganic hybrid binder inevitably has excellent solvent resistance, but the adhesion with the transparent coating layer, the flexibility of the transparent conductive layer, etc. It is necessary to select appropriately so as not to deteriorate.

  The ratio of the conductive oxide fine particles and the binder component in the coating liquid for forming the transparent conductive layer is assumed that the specific gravity of the conductive oxide fine particles and the binder component is about 7.2 (specific gravity of ITO) and about 1.2 respectively ( Assuming that the specific gravity of a normal organic resin binder), the conductive oxide fine particles: binder component = 85: 15 to 97: 3, preferably 87:13 to 95: 5 is preferred in terms of weight ratio. The reason is that when the rolling treatment of the present invention is carried out, if the binder component is more than 85:15, the resistance of the transparent conductive layer becomes too high, and conversely if the binder component is less than 97: 3, the strength of the transparent conductive layer is lowered. At the same time, sufficient adhesion with the transparent coating layer cannot be obtained.

  The coating liquid for forming a transparent coating layer used in the present invention is a transparent resin (transparent coating) containing fibers and / or flaky particles that have been subjected to an adhesion improvement treatment (coupling agent treatment, plasma treatment, etc.) on the surface as necessary. It can be obtained by dispersing in a solvent containing the binder component of the layer. If necessary, various coupling agents such as a silicone coupling agent, various polymer dispersants, and various surfactants such as anionic, nonionic, and cationic surfactants may be used as the dispersant. These dispersants can be appropriately selected according to the type of fiber and / or flaky particles used and the dispersion treatment method. As the dispersion treatment, general-purpose methods such as ultrasonic treatment, homogenizer, paint shaker, and bead mill can be applied. What is necessary is just to set suitably the density | concentration of transparent resin and a fiber and / or flaky particle | grains according to the coating method to be used. The blending ratio of the transparent resin and the fibers and / or flaky particles depends on the material used, but the blending amount of the fibers and / or flaky particles is 5 with respect to the total of the transparent resin and the fibers and / or flaky particles. -60 volume% is good, and 10-30 volume% is more preferable. If the amount is less than 5% by volume, the reinforcing effect by the fibers and / or flaky particles is not observed. If the amount exceeds 60% by volume, the amount of the fibers and / or flaky particles is too much, the transparent coating layer becomes porous, and the strength decreases. At the same time, the surface unevenness of the transparent coating layer becomes large, and it becomes difficult to uniformly form the transparent conductive layer thereon.

  The manufacturing method of the coating liquid for transparent conductive layer formation used by this invention is demonstrated. First, the conductive oxide fine particles are mixed with a solvent and, if necessary, a dispersant, and then dispersed to obtain a conductive oxide fine particle dispersion. Examples of the dispersant include various coupling agents such as a silicon coupling agent, various polymer dispersants, and various surfactants such as anionic, nonionic, and cationic types. These dispersants can be appropriately selected according to the type of conductive oxide fine particles used and the dispersion treatment method. Even if no dispersant is used, a good dispersion state may be obtained depending on the combination of the conductive oxide fine particles and the solvent to be applied and the dispersion method. Since the use of a dispersant may deteriorate the resistance and weather resistance of the film, a coating liquid for forming a transparent conductive layer that does not use a dispersant is most preferable. As the dispersion treatment, general-purpose methods such as ultrasonic treatment, homogenizer, paint shaker, and bead mill can be applied.

  By adding a binder component to the obtained conductive oxide fine particle dispersion, and further adjusting the components such as the concentration of the conductive oxide fine particles and the solvent composition, a coating liquid for forming a transparent conductive layer can be obtained. Here, the binder component is added to the dispersion of the conductive oxide fine particles, but it may be added in advance before the above-described dispersion step of the conductive oxide fine particles, and there is no particular limitation. What is necessary is just to set an electroconductive oxide fine particle density | concentration suitably according to the coating method to be used.

  There is no restriction | limiting in particular as a solvent used for the coating liquid for transparent conductive layer formation, According to the coating method, film forming conditions, and the material of a transparent coating layer, it can select suitably. For example, water, methanol (MA), ethanol (EA), 1-propanol (NPA), isopropanol (IPA), butanol, pentanol, benzyl alcohol, diacetone alcohol (DAA) and other alcohol solvents, acetone, methyl ethyl ketone ( MEK), methyl propyl ketone, methyl isobutyl ketone (MIBK), ketone solvents such as cyclohexanone and isophorone, ester solvents such as ethyl acetate, butyl acetate and methyl lactate, ethylene glycol monomethyl ether (MCS), ethylene glycol monoethyl ether (ECS), ethylene glycol isopropyl ether (IPC), ethylene glycol monobutyl ether (BCS), ethylene glycol monoethyl ether acetate, ethylene glycol Butyl ether acetate, propylene glycol methyl ether (PGM), propylene glycol ethyl ether (PE), propylene glycol methyl ether acetate (PGM-AC), propylene glycol ethyl ether acetate (PE-AC), diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Diethylene glycol monobutyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, dipropylene glycol monomethyl ether, Glycol derivatives such as propylene glycol monoethyl ether and dipropylene glycol monobutyl ether, benzene derivatives such as toluene, xylene, mesitylene and dodecylbenzene, formamide (FA), N-methylformamide, dimethylformamide (DMF), dimethylacetamide, dimethylsulfate Examples include foxoxide (DMSO), N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, ethylene glycol, diethylene glycol, tetrahydrofuran (THF), chloroform, mineral spirits, terpineol, and the like. Absent.

Next, the manufacturing method of the dispersive electroluminescent element according to the present invention will be described.
First, using a coating solution for forming a transparent coating layer containing a resin binder (transparent resin), visible light transmissive fibers and / or flaky particles, and a solvent, screen printing, blade coating, wire bar coating, spray coating, roll coating Then, it is applied, dried and cured on the base film by a method such as gravure printing to form a transparent coating layer reinforced with fibers and / or flaky particles. Here, prior to the formation of the transparent coating layer, if necessary, a transparent conductive layer forming coating liquid in which conductive oxide fine particles are dispersed in a solvent containing a binder component on a base film is used, as described above. The second transparent conductive layer is formed by applying and drying by the above method, or by applying a compression treatment to the second application layer formed by applying and drying, followed by curing. It can also be left. As described above, since the resistance value of the second transparent conductive layer may be a relatively high value, it is not always necessary to perform a rolling treatment. In this case, the resistance value is deteriorated, but the purpose is to improve the film strength and adhesion. In addition, a coating liquid for forming a transparent conductive layer having a binder component larger than the blending ratio of the conductive oxide fine particles and the binder component described above may be used.
Next, using the coating liquid for forming the transparent conductive layer, a coating layer is formed by applying and drying on the transparent coating layer in the same manner as described above, and then the above-described compression treatment is performed. The compression treatment is preferably performed by rolling a metal roll. Thereafter, the coating layer that has been subjected to the rolling treatment is subjected to a curing treatment such as drying curing, heat curing, or ultraviolet curing depending on the type of the coating solution to become a transparent conductive layer.
In this specification, “coating layer” is used to mean a film obtained by applying and drying a coating liquid for forming a transparent conductive layer, and “transparent conductive layer” is a coating for forming a transparent conductive layer. It is used to mean a film finally obtained using a liquid. Therefore, the “transparent conductive layer” is clearly distinguished from the “coating layer” of the coating liquid for forming the transparent conductive layer.

  The phosphor layer, dielectric layer, and back electrode layer formed on the transparent conductive layer can be sequentially formed by screen printing or the like. The paste used when apply | coating (printing) forming each layer of a fluorescent substance layer, a dielectric material layer, and a back electrode layer can use the paste marketed. The phosphor layer paste and the dielectric layer paste are obtained by dispersing phosphor particles and dielectric fine particles in a solvent containing a binder mainly composed of fluoro rubber, and the back electrode layer paste is composed of carbon fine particles and the like. Conductive fine particles are dispersed in a solvent containing a thermosetting resin binder.

  Here, when screen-printing each layer such as a phosphor layer on the transparent conductive layer, generally, there is a method of fixing the film by using a suction stage having a large number of small-diameter holes and reducing the hole portions under reduced pressure. Used. If the base film is thin, the film in the hole portion is deformed by the reduced pressure, resulting in a dent, and the problem arises that the dent marks appear on the screen-printed film. Since a base film having sufficient strength is sometimes used and peeled off after the dispersion type EL element is formed, the above problem can be prevented. The base film used in the present invention has a heat treatment temperature of 130 to 130 in advance in the manufacturing process of the dispersion type EL element in order to prevent shrinkage (dimensional change) due to heat treatment in the manufacturing process of the dispersion type EL element and curling of the film. It is preferable to perform heat treatment (heat shrinkage treatment) at 150 ° C. When a thermoplastic resin or thermosetting resin is used as the transparent resin of the coating liquid for forming the transparent coating layer, the heat treatment temperature is used for drying or heat curing after the coating liquid for forming the transparent coating layer is applied to the base film. If it can be set to 120-150 degreeC, it is also possible to omit the said heat processing (thermal contraction process).

  The transparent conductive layer, the phosphor layer, the dielectric layer, and the back electrode layer constitute the main part of the dispersion-type EL element. However, in an actual dispersion-type EL element, the collector electrode (silver paste) of the transparent conduction layer is used. Formation), a lead electrode (formed with silver paste) of the back electrode layer, a short circuit between electrodes, an insulating protective coating (formed with insulating paste) for preventing electric shock, and the like are further formed.

Since the dispersion type electroluminescent device of the present invention uses a transparent coating layer reinforced with fibers and / or flaky particles, the dispersion type EL device has excellent strength and is thin and flexible. Therefore, it is applied as a light-emitting element incorporated in a key input component of a device, and it is possible to obtain a good click feeling of key operation without performing a special structure or device on the keypad. Therefore, it can be applied as a light emitting element incorporated in a key input component of a device such as a mobile phone, a remote controller, or a portable information terminal.
[Example]

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples. Further, “%” in the text indicates “% by weight”, and “part” indicates “part by weight”.

  After mixing the granular ITO fine particles (trade name: SUFP-HX, manufactured by Sumitomo Metal Mining) with an average particle size of 0.03 μm with 24 g of methyl isobutyl ketone (MIBK) as a solvent and 36 g of cyclohexanone, and performing a dispersion treatment, 3.8 g of urethane acrylate UV curable resin binder and 0.2 g of photoinitiator (Darocur 1173) were added and stirred well to form a transparent conductive layer forming coating solution in which ITO fine particles having an average dispersed particle size of 130 nm were dispersed (A Liquid).

Potassium titanate fiber [K ₂ O · 6TiO ₂ ] (length: 10-20 μm and thickness: 0.3-0.6 μm) surface-treated with a silicon coupling agent (γ-methacryloxypropyltrimethoxysilane) (Otsuka Chemical) Manufactured by Tismo N, true specific gravity = 3.5 to 3.6) 15 g of polymer dispersing agent 0.15 g of polymer dispersant is mixed with 50 g of methyl isobutyl ketone (MIBK) as a solvent, and after dispersion treatment, as a transparent resin 33.1 g of urethane acrylate UV curable resin (manufactured by Negami Kogyo Co., Ltd., Art Resin H-14 [developed product]) and 1.75 g of photopolymerization initiator (Darocur 1173) were added and stirred well, and potassium titanate fiber Obtained a coating liquid for forming a transparent coating layer (liquid B) dispersed in a solvent containing a transparent resin. The fiber content in the coating liquid for forming a transparent coating layer is 12.6 vol% when the specific gravity of the transparent resin (including the photopolymerization initiator) is calculated to be about 1.2.

A wire bar coating (wire diameter: 0.5 mm) is applied to the transparent coating layer forming coating liquid (B liquid) on a PET film (manufactured by Teijin Ltd., thickness 100 μm) that has not been subjected to an easy adhesion treatment as a base film. ), Dried at 60 ° C. for 5 minutes, and then cured with an ultraviolet ray (high pressure mercury lamp, 100 mW / cm 2 × 4 seconds) and made of an acrylic urethane resin reinforced with potassium titanate fiber (film thickness: about 12 μm) was obtained. The base film on which the transparent coating layer was formed was a white coating film, and the film characteristics were a visible light transmittance of 40.8% and a haze value of 90.8%. (The visible light absorption is small but the scattering is very large, so the apparently measured transmittance is low.) On this transparent coating layer, the transparent conductive layer forming coating liquid (A liquid) is wire bar coated. (Wire diameter: 0.15 mm), dried at 60 ° C. for 1 minute, and then rolled with a hard chromium plated steel roll having a diameter of 100 mm (linear pressure: 200 kgf / cm = 196 N / mm, nip width: 0.9 mm) Further, the binder component is cured with a high-pressure mercury lamp (in nitrogen, 100 mW / cm ² × 2 seconds), and a transparent conductive layer composed of ITO fine particles and a binder closely packed on the transparent coating layer ( Film thickness: about 1.0 μm), and a laminated film comprising a transparent coating layer / transparent conductive layer reinforced with base film / fiber was obtained. The packing density of the conductive fine particles in the transparent conductive film layer after the rolling treatment was about 55 vol%. In the laminated film, the transparent coating layer reinforced with the fiber having the transparent conductive layer was easily peeled off at the interface with the base film.
The base film is preliminarily subjected to heat treatment at 150 ° C. for 10 minutes in order to prevent shrinkage (size change) due to heat treatment in the manufacturing process of the dispersion type EL element described later and curling of the film. A transparent coating layer is formed.

  The film characteristics of this transparent conductive layer were visible light transmittance: 87.7%, haze value: 1.2%, and surface resistance value: 610Ω / □. Note that the surface resistance value is measured one day after the formation of the transparent conductive layer because it tends to temporarily decrease immediately after curing due to the influence of ultraviolet irradiation during binder curing.

In addition, the transmittance | permeability and haze value of the above-mentioned transparent conductive layer are values only of a transparent conductive layer, and are calculated | required by the following formulas 1 and 2, respectively. (However, as described above, the base film on which the transparent coating layer reinforced with fibers is formed has a visible light transmittance of 40.8% and a haze value of 90.8%, but has transparency, but is transparent. (This is not good, so the value calculated by the following formula may have a large error.)
[Calculation Formula 1]
Transmittance (%) of transparent conductive layer = [(transmittance measured with base film on which transparent conductive layer and transparent coating layer are formed) / transmittance of base film on which transparent coating layer is formed] × 100
[Calculation Formula 2]
Haze value of transparent conductive layer (%) = (Haze value measured with base film on which transparent conductive layer and transparent coating layer are formed) − (Haze value of base film on which transparent coating layer is formed)

  The surface resistance of the transparent conductive layer was measured using a surface resistance meter Loresta AP (MCP-T400) manufactured by Mitsubishi Chemical Corporation. The haze value and visible light transmittance were measured using a haze meter (HR-200) manufactured by Murakami Color Research Laboratory.

  Next, a phosphor paste (made by DuPont, 7154J) in which zinc sulfide particles, which are phosphors, are dispersed in a resin solution containing a fluoropolymer as a main component on the transparent conductive layer of the laminated film, is prepared. Screen printing was performed to a size of 4 × 5 cm using a mesh polyester screen and dried at 120 ° C. for 30 minutes to form a phosphor layer.

  On the phosphor layer, a dielectric paste (made by DuPont, 7153) in which barium titanate particles are dispersed in a resin solution containing a fluoropolymer as a main component is prepared, and 4 × 5 cm using a 200 mesh polyester screen. Was printed (120 ° C. × 30 minutes), and this was repeated twice to form a dielectric layer.

  A carbon conductive paste (FEC-198, manufactured by Fujikura Kasei Co., Ltd.) is screen-printed to a size of 3.5 × 4.5 cm using a 200 mesh polyester screen on the dielectric layer, dried at 130 ° C. for 30 minutes, and back electrode layer Formed.

  An Ag lead wire for voltage application is formed on one end of the transparent conductive layer and the back electrode layer using a silver conductive paste, and the dispersion type EL device according to Example 1 (base film / transparent coating layer reinforced with fiber) / Transparent conductive layer / phosphor layer / dielectric layer / back electrode layer). In order to prevent short-circuit between electrodes, electric shock, etc., an insulating layer is formed using an insulating paste (XB-101G, manufactured by Fujikura Kasei Co., Ltd.) as an insulating protective coating for the transparent conductive layer and the back electrode layer as necessary. However, since it is not a part related to the essence of the present invention, details are omitted.

In the dispersion type EL device, the base film was easily peeled off at the interface with the transparent coating layer reinforced with fibers. When a voltage of 100 V and 400 Hz was applied between the voltage application leads of the dispersion type EL element obtained by peeling the base film, the dispersion type EL element emitted light uniformly, and its luminance was measured to be 49 Cd / m. ² . The luminance was measured with a luminance meter (trade name: BM-9, manufactured by Topcon Corporation).

After mixing the granular ITO fine particles (trade name: SUFP-HX, manufactured by Sumitomo Metal Mining) with an average particle size of 0.03 μm with 24 g of methyl isobutyl ketone (MIBK) as a solvent and 36 g of cyclohexanone, and performing a dispersion treatment, Add 3.8 g of urethane acrylate UV curable resin binder having adhesive strength that can be peeled off from PET and 0.2 g of photoinitiator (Darocur 1173) and stir well to obtain ITO fine particles with an average dispersed particle size of 130 nm. A dispersed coating liquid for forming a transparent conductive layer (C liquid) was obtained.
A transparent conductive layer forming coating solution (C solution) is wire bar coated (wire diameter: 0.075 mm) on a PET film (Teijin Limited, thickness 100 μm) that has not been subjected to easy adhesion treatment as a base film. After drying at 60 ° C. for 1 minute, the same rolling treatment as in Example 1 (linear pressure 200 kgf / cm = 196 N / mm, nip width = 0.9 mm) was performed, and further the binder component was cured with a high-pressure mercury lamp ( A second transparent conductive layer (film thickness: about 0.4 μm) composed of ITO fine particles and a binder was formed by performing 100 mW / cm ² × 2 seconds in nitrogen. The second transparent conductive layer had a visible light transmittance of 95.2%, a haze value of 2.7%, and a surface resistance value of 2600Ω / □. This is the same as Example 1 except that a transparent coating layer reinforced with fibers is formed on the second transparent conductive layer. A layer (film thickness: about 1.0 μm) was formed, and a laminated film composed of base film / second transparent conductive layer / transparent coating layer reinforced with fibers / transparent conductive layer was obtained. The packing density of the conductive fine particles in the transparent conductive film layer after the rolling treatment was about 54 vol%. In the laminated film, the transparent coating layer reinforced with the fiber having the second transparent conductive layer and the transparent conductive layer was easily peeled off at the interface between the base film and the second transparent conductive layer.
The base film is preliminarily subjected to heat treatment at 150 ° C. for 10 minutes in order to prevent shrinkage (dimensional change) due to heat treatment in the dispersion type EL device manufacturing process and curling of the film, and then a second film is formed thereon. The transparent conductive layer is formed.
The transparent conductive layer had a visible light transmittance of 87.5%, a haze value of 1.5%, and a surface resistance value of 620Ω / □. A dispersion type EL device according to Example 2 was obtained in the same manner as in Example 1 except that this transparent conductive layer was obtained.
In addition, the transmittance | permeability and haze value of the above-mentioned transparent conductive layer are values only of a transparent conductive layer, and are calculated | required by the following formulas 3 and 4, respectively.
[Calculation Formula 3]
Transmissivity of transparent conductive layer (%) = [(transmittance measured for each base film on which the transparent conductive layer, the transparent coating layer, and the second transparent conductive layer are formed) / the transparent coating layer and the second transparent conductive layer Permeability of base film on which is formed] × 100
[Calculation Formula 4]
Haze value (%) of the transparent conductive layer = (haze value measured for each base film on which the transparent conductive layer, the transparent coating layer, and the second transparent conductive layer are formed) − (the transparent coating layer and the second transparent conductive layer) (Haze value of the base film on which is formed)

In the dispersion type EL element, the base film was easily peeled off at the interface with the second transparent conductive layer. When a voltage of 100 V and 400 Hz was applied between the voltage application leads of the dispersion type EL element obtained by peeling this base film, the dispersion type EL element emitted light uniformly, and its luminance was measured to be 47 Cd / m. ² .
[Comparative Example 1]

  38 g of urethane acrylate UV curable resin (manufactured by Negami Kogyo Co., Ltd., Art Resin H-14 [developed product]) and 2 g of a photopolymerization initiator (Darocur 1173) as a transparent resin are mixed with 60 g of methyl isobutyl ketone (MIBK) A coating solution for forming a transparent coating layer (D solution) was obtained.

A wire bar coating (wire diameter: 0.5 mm) is applied to the above coating liquid for forming a transparent coating layer (D liquid) on a PET film (manufactured by Teijin Ltd., thickness: 100 μm) that has not been subjected to easy adhesion treatment as a base film. ), Dried at 60 ° C. for 5 minutes, and then UV-cured (high pressure mercury lamp, 100 mW / cm 2 × 4 seconds) to obtain a transparent coating layer (film thickness: about 12 μm) made of an acrylic urethane resin not containing fibers. It was. The base film on which the transparent coating layer was formed was transparent in appearance, and the film characteristics were a visible light transmittance of 90.2% and a haze value of 2.0%.
Except that the transparent conductive layer was formed on the transparent coating layer, the same procedure as in Example 1 was performed, and the transparent conductive layer (thickness: about 1) composed of ITO fine particles and a binder closely packed on the transparent coating layer. 0.0 μm) to obtain a laminated film comprising a transparent coating layer / transparent conductive layer not reinforced with base film / fiber. The packing density of the conductive fine particles in this transparent conductive film layer was about 55 vol%.
In the laminated film, the transparent coating layer not reinforced with the fiber having the transparent conductive layer was easily peeled off at the interface with the base film.
In order to prevent shrinkage (dimensional change) due to heat treatment in the dispersion type EL device manufacturing process and curling of the film, the base film is preliminarily heated at 150 ° C. for 10 minutes, and then a transparent coating is formed thereon. Forming a layer.

  The film characteristics of this transparent conductive layer were visible light transmittance: 90.5%, haze value: 2.7%, and surface resistance value: 590Ω / □. Note that the surface resistance value is measured one day after the formation of the transparent conductive layer because it tends to temporarily decrease immediately after curing due to the influence of ultraviolet irradiation during binder curing.

  A dispersion type EL device according to Comparative Example 1 was obtained in the same manner as in Example 1 except that the base film on which the transparent conductive layer was formed was used.

In the dispersion type EL device, the base film was easily peeled off at the interface with the transparent coating layer. When a voltage of 100 V and 400 Hz was applied between the voltage application leads of the dispersion type EL element obtained by peeling off the base film, the dispersion type EL element emitted light uniformly, and its luminance was measured to be 53 Cd / m. ² .

"Strength evaluation of distributed EL elements"
Transparent coating layer reinforced with fibers having a transparent conductive layer in each Example (obtained by peeling and removing the base film from the laminated film) and transparent coating not reinforced with fibers having the transparent conductive layer of Comparative Example When the breaking strength was measured by making the layer (obtained by peeling and removing the base film from the laminated film) into a strip shape, the transparent coating layer having the transparent conductive layer of each example was transparent having the transparent conductive layer of the comparative example The breaking strength was about twice that of the coating layer.
Further, a voltage of 100 V or 400 Hz is applied between the voltage application lead wires of the dispersion type EL element according to each example (with the base film peeled off) and the dispersion type EL element according to the comparative example (with the base film peeled off). When applying a tensile load to the device while applying it and observing its light emission state, the device of the comparative example was cracked in the transparent coating layer by applying a lower load than the device of each example, and the conductivity of the transparent conductive layer was Deteriorated, and the light emission state deteriorated.

"Flexibility evaluation of distributed EL elements"
Dispersion type EL elements according to the respective examples (with the base film peeled off) and dispersion type EL elements according to the comparative examples (with the base film peeled off) on a rod having a diameter of 3 mm and the light emitting surfaces thereof on the inside and outside, respectively After being wound once so that a voltage of 100 V and 400 Hz was applied between the voltage application lead wires of the dispersion type EL element, the light emission state of the element was observed. In each Example and Comparative Example, no change was observed in the light emission state.

“Evaluation of solvent resistance of dispersive EL devices”
In each of the Examples and Comparative Examples, after forming a transparent conductive layer on the transparent coating layer, the surface of the transparent conductive layer was rubbed 10 times with a cotton swab dipped in acetone, and the change in appearance was observed. In addition, a dispersion type EL device was manufactured using the transparent conductive layer thus evaluated, and a voltage of 100 V and 400 Hz was applied between the voltage application leads, and the light emission state of the device was observed. Luminescence was uniform including the part, and no influence of acetone was observed.

It is sectional drawing which shows the basic structure of the conventional dispersion-type EL element. It is sectional drawing which shows another structure of the conventional dispersion-type EL element. It is sectional drawing which shows the dispersion type EL element of the basic structure which concerns on this invention. It is sectional drawing which shows the dispersion type EL element of another structure which concerns on this invention. It is sectional drawing which shows the dispersion type EL element of another structure which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent plastic film 2 Transparent conductive layer 3 Phosphor layer 4 Dielectric layer 5 Back electrode layer 6 Current collecting electrode 7 Insulating protective layer 8 Base film 9 Transparent coating layer 10 2nd transparent conductive layer

Claims (16)

  A dispersive electroluminescence device formed at least on a surface of a base film in order, comprising at least a transparent coating layer, a transparent conductive layer, a phosphor layer, a dielectric layer, and a back electrode layer, wherein the transparent coating layer Is a coating reinforced with fibers and / or flaky particles formed on the surface of a base film using a coating solution for forming a transparent coating layer mainly composed of transparent resin and visible light transmissive fibers and / or flaky particles The transparent conductive layer is formed by applying a coating solution for forming a transparent conductive layer mainly composed of conductive oxide particles and a binder onto the surface of the transparent coating layer. A dispersive electroluminescent material characterized in that the formed coating layer is subjected to compression treatment and then cured. Scan element.   A second transparent conductive layer is further formed between the transparent base film and the transparent coating layer, and the second transparent conductive layer is a coating for forming a transparent conductive layer mainly composed of conductive oxide particles and a binder. A compression treatment is applied to the second coating layer formed by applying the liquid on the surface of the base film and curing, or the second coating layer formed by applying the coating liquid for forming the transparent conductive layer on the surface of the base film. 2. The dispersion type electroluminescent device according to claim 1, wherein the dispersion type electroluminescent device is cured after being applied.   The dispersion type electroluminescent device according to claim 1, wherein the transparent coating layer has a thickness of 50 μm or less.   The dispersion type electroluminescent device according to claim 1, wherein the conductive oxide fine particles contain one or more of indium oxide, tin oxide, and zinc oxide as a main component.   5. The dispersion type electroluminescent device according to claim 4, wherein the conductive oxide fine particles mainly composed of indium oxide are indium tin oxide fine particles.   The dispersion type electroluminescent device according to claim 1 or 2, wherein the binder has crosslinkability, and the transparent conductive layer and the second transparent conductive layer have organic solvent resistance. .   The dispersion type electroluminescent device according to claim 1, wherein the compression treatment is performed by rolling a metal roll.   The dispersion type electroluminescent device according to claim 1, wherein the base film is peeled and removed at an interface with the transparent coating layer or the second transparent conductive layer.   9. A dispersion type electroluminescence element, wherein the dispersion type electroluminescence element according to claim 1 is applied as a light emitting element incorporated in a key input component of the device.   The distributed electroluminescence device according to claim 9, wherein the device is a mobile phone, a remote controller, or a portable information terminal.   A method for producing a dispersive electroluminescent device, comprising sequentially forming at least a transparent coating layer, a transparent conductive layer, a phosphor layer, a dielectric layer, and a back electrode layer on a surface of a base film, wherein Conductivity on the surface of the transparent coating layer reinforced with fibers and / or flaky particles formed using a coating liquid for forming a transparent coating layer mainly composed of light-transmitting fibers and / or flaky particles A coating layer is formed using a coating liquid for forming a transparent conductive layer mainly composed of oxide fine particles and a binder, and then the base film on which the transparent coating layer and the coating layer are formed is subjected to a compression treatment and then cured. And forming a transparent conductive layer to produce a dispersion type electroluminescent device.   A method for producing a dispersive electroluminescent device, comprising: forming at least a transparent coating layer, a transparent conductive layer, a phosphor layer, a dielectric layer, and a back electrode layer sequentially on a base film surface, wherein the base film surface It is applied and cured using a coating solution for forming a transparent conductive layer mainly composed of conductive oxide fine particles and a binder, or a second coating layer formed by coating is compressed and then cured. A second transparent conductive layer is formed, and a transparent coating layer is formed on the surface of the second transparent conductive layer. The transparent coating layer is mainly composed of a transparent resin and visible light transmissive fibers and / or flaky particles. Using the coating solution, a transparent coating layer reinforced with fibers and / or flaky particles is applied and formed, and conductive oxide fine particles and a binder are formed on the surface of the transparent coating layer. After forming a coating layer using a coating liquid for forming a transparent conductive layer containing as a main component, and then compressing the base film, the second transparent conductive layer, the transparent coating layer, and the coating layer A method for producing a dispersion-type electroluminescent element, comprising curing to form a transparent conductive layer.   The dispersion type electroluminescence, wherein after the production process of the dispersion type electroluminescence device according to claim 11 or 12, the base film is further peeled and removed from the interface with the transparent coating layer or the second transparent conductive layer. Device manufacturing method.   The method of manufacturing a dispersion type electroluminescent element according to claim 11 or 12, wherein the compression treatment is performed by rolling a metal roll.   The method of manufacturing a dispersion type electroluminescent device according to claim 14, wherein the rolling treatment is performed at a linear pressure of 29.4 to 784 N / mm (30 to 800 kgf / cm). The said rolling process is linear pressure: 98-490 N / mm (100-500 kgf / cm), The manufacturing method of the dispersion-type electroluminescent element of Claim 14 characterized by the above-mentioned.