JP6038966B2 - Paper, light emitting element, and paper manufacturing method - Google Patents

Description

  The present invention relates to paper, a light emitting element, and a method for manufacturing paper.

  Conventionally, an electroluminescence (EL) element using an inorganic compound phosphor has a structure in which a layer in which an inorganic compound is dispersed in a binder such as a polymer material is sandwiched between transparent electrodes via an insulating film. The type was known. This is a type in which a high voltage is applied to the dispersed phosphor to convert the large kinetic energy lost by the collision of electrons flowing in the electric field into excitation energy and emit light, and the insulating film layer is fluorescent. It was essential to apply a high voltage to the body.

  In order for this type of EL element to operate effectively, it is preferable that it can be driven at as low a voltage as possible, while a high voltage is required to be applied to the phosphor, and thus a thin dispersion layer and high insulation are required. It has been desired to construct a thin insulating film. However, as the dispersion layer becomes thinner, the amount of phosphor decreases and the emission intensity decreases, and therefore various optimizations have been made on the optimization of phosphors and insulating materials to be used and on the element configuration.

  An EL element using polyacid as a light emitting material is also known. In Non-Patent Document 1, a light emitting layer of polyacid (thickness 50 to 80 μm) is laminated on an ITO electrode by a sedimentation method, dried, a polyester film (thickness 6 μm) is laminated, and an ITO electrode is laminated. An EL device manufactured by is disclosed.

  On the other hand, an example of using paper as a base material when producing a functional device has been reported. For example, Patent Document 1 discloses a technique for laminating a polyacid film exhibiting photochromic properties on paper. Patent Document 2 describes that a paper impregnated with a gel containing an ionic liquid and a light emitting substance is used as a light emitting layer of a light emitting display device.

JP 2011-184597 A JP 2009-282451 A

Toshihiro Yamase, Yuta Ueda, Journal of The Electrochemical Society, vol. 140, issue 8, pp. 2378-2384, 1993.

  However, the device described in Non-Patent Document 1 has problems such as non-uniformity of the light emitting layer and low mechanical strength. Further, the device described in Non-Patent Document 1 requires an applied voltage of −0.7 kV to −1.0 kV, and breakdown due to dielectric breakdown due to this high voltage frequently occurs. There was also a problem that it was difficult to emit light.

  An object of the present invention is to provide a method for easily manufacturing a light-emitting element that provides stable light emission. Further, by applying the method of the present invention, a product using the function of polyacid can be easily produced.

In order to achieve the object of the present invention, for example, the paper manufacturing method of the present invention comprises the following arrangement. That is,
Applying a coating solution containing polyacid to paper;
A step of precipitating an insoluble salt of polyacid by applying a coating solution containing a metal cation or an organic cation having a valence of 2 or more to the paper;
It is characterized by having.

  A light-emitting element that provides stable light emission can be easily manufactured. Further, by applying the method of the present invention, a product using the function of polyacid can be easily produced.

The figure explaining the coating method of the coating liquid which concerns on one Embodiment. 5 is a flowchart of processing according to the first embodiment. The schematic diagram which shows the structure of the light emitting element which concerns on one Embodiment. The block diagram of the EL measurement system used in the Example. FIG. 11 shows a waveform of EL light emission intensity of the light-emitting element manufactured in Example 1-2. FIG. 6 shows an emission spectrum of the light-emitting element manufactured in Example 1-2. FIG. 9 shows a waveform of EL light emission intensity of the light-emitting element manufactured in Example 2. FIG. 6 shows an emission spectrum of the light-emitting element manufactured in Example 2. FIG. 6 shows an emission spectrum of the light-emitting element manufactured in Example 3. 10 is a flowchart of processing according to the second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the following examples.

[Embodiment 1]
The paper according to Embodiment 1 carries an insoluble salt of polyacid. In one embodiment, an insoluble salt of polyacid is supported in a matrix of fibers that make up the paper.

  Paper is a fiber layered. In one embodiment, the paper is a layer of plant fibers or a layer of material containing plant fibers. In another embodiment, the paper may be composed of or include synthetic fibers. The size of the paper is not particularly limited. Moreover, there is no restriction | limiting in particular in the thickness of paper, Paper of arbitrary thickness can be used according to a use.

  The type of paper is not particularly limited. For example, diatomaceous earth paper containing diatomaceous earth can also be used. Thus, the paper may contain additives other than fibers. Examples of usable paper include Deerite paper, FLS paper, water-resistant paper, sun silica paper, diatomaceous earth paper, and the like manufactured by Sanzen Paper Co., Ltd.

  In one embodiment, the paper according to this embodiment is dry. Paper in a dry state is easy to handle. Further, it is expected that the paper in a dry state does not change in properties without special sealing. The moisture contained in the paper is preferably 12% or less, more preferably 10% or less, and even more preferably 8% or less. The moisture of the paper can be measured according to JIS P 8127: 2010.

  The thickness of the paper is not particularly limited and can be appropriately adjusted according to the application. In one embodiment, the thickness of the paper is preferably 10 μm or more, and more preferably 30 μm or more. On the other hand, the thickness of the paper is preferably 300 μm or less, and more preferably 100 μm or less.

  A polyacid is a polyoxoacid ion of a metal oxide formed by dehydration condensation of many monooxoacid ions in which several (usually 4 or 6) oxygen atoms are bonded to a metal atom, and is usually an anion. is there. The polyacid includes both an isopolyacid having a polynuclear structure in which a single kind of metal oxoacid is condensed and a heteropolyacid having a multinuclear structure in which two or more kinds of oxoacids are condensed. The polyacid may be a solvate such as a hydrate. Although the metal atom which comprises polyoxo acid is not specifically limited, Molybdenum, europium, tungsten, antimony, vanadium, titanium, etc. are mentioned.

  As for polyacids, for example, edited by Chemical Society of Japan, Polyacid Chemistry, Quarterly Chemistry Review, Society Press Center, No. 20, 1993, and Toshihiro Yamase, Handbook on the Physics and Chemistry of Rare Earths, ed. Karl Gschneidner Jr. Jean-Claude Buenzli, and Vitalij Pecharsky, Elsevier BV, vol. 39, pp. 297-356, 2009.

  Polyacids are known for a variety of uses (eg, catalytic, electrical, magnetic, electrochemical, optical and pharmaceutical uses). Therefore, the paper according to the present embodiment can be used as a functional paper for various applications depending on the type of polyacid.

For example, as the light-emitting polyacid, a polyacid having a light-emitting polyacid matrix, a rare earth ion such as Eu ³⁺ or Tb ^{3+ that functions} as a light-emitting center, or a polymetal including a transition metal ion such as Cr ³⁺ or Mn ⁴⁺ Examples include acids. For luminescent polyacids, see Toshihiro Yamase, Chemical Reviews 98, 307, 1998, and Toshihiro Yamase, Handbook on the Physics and Chemistry of Rare Earths, ed. Karl Gschneidner Jr., Jean-Claude Buenzli, and Vitalij Pecharsky. Elsevier BV, vol. 39, pp. 297-356, 2009.

  Luminescence refers to the property of emitting light when energy is applied. For example, polyacids exhibiting luminescent properties can emit light when given X-rays, ultraviolet rays, electron beams or beta rays. Moreover, the polyacid which shows luminescent property can also light-emit when a voltage is applied other than irradiation of electromagnetic waves, light, and an electron.

Examples of the polyacid matrix having strong luminescence include Cs ₄ [W ₁₀ O ₃₂ ] · 20H ₂ O, K _5.5 H _1.5 [SbW ₆ O ₂₄ ] · 6H ₂ O, K ₆ [Mo ₇ O ₂₄ ] · 4H ₂ O and the like.

Moreover, as a polyacid containing a light emission center, [EuW ₁₀ O ₃₆ ] ⁹⁻ , [DyW ₁₀ O ₃₆ ] ⁹⁻ , [TbW ₁₀ O ₃₆ ] ⁹⁻ , [CrMo ₆ O ₂₄ ] ⁹⁻ , Polyacids containing [MnW ₆ O ₂₄ ] ⁸⁻ or [Mn (Nb ₆ O ₁₉ ) ₂ ] ^{12− and the} like can be mentioned.

  Such a paper carrying a polyacid can be used as a luminescent paper, more specifically as a light emitting layer of an EL light emitting element. Such a luminescent paper can be used for various purposes because it can be easily folded and attached to a device. In paper carrying a polyacid according to one embodiment, it has been found that the polyacid performs the same function as in the solid state. Conventionally, papers coated with fluorescent dyes of xanthene organic compounds such as sodium fluorescein or rhodamine bee are known. However, xanthene dyes emit strong light in a solution such as water or alcohol, but the light emission efficiency is remarkably reduced in an environment with little moisture. Therefore, it is necessary to bring the environment around the dye coated on paper close to the environment in the solution. there were. On the other hand, in one embodiment, it was confirmed that a polyacid exhibiting luminescence in a solid state exhibits luminescence even in a state where it is supported on paper.

Examples of the polyacid having antiviral activity include K ₁₁ H [(VO) ₃ (SbW ₉ O ₃₃ ) ₂ ] · 27H ₂ O and K ₇ [PTi ₂ W ₁₀ O ₄₀ ] · 6H ₂ O. It is done. Furthermore, as polyacids having antibacterial action, K ₆ [P ₂ W ₁₈ O ₆₂ ] · 14H ₂ O, K ₇ [SiMo ₁₂ O ₄₀ ] · 3H ₂ O or K ₇ [PTi ₂ W ₁₀ O ₄₀ ] · 6H ₂ O, and the like. Such a paper carrying a polyacid can be used for sanitary goods. For polyacids exhibiting such biological activity, Toshihiro Yamase, Biomedical Inorganic Polymers, Bioactivity and Applications of Natural and Synthetic Polymeric Inorganic Molecules, eds.Werner EG Mueller, Xiaohong Wang, Heinz C. Schroeder, Springer-Verlag Berlin Heidelberg , pp.65-116, 2013.

  In the present embodiment, the polyacid carried on the paper may be a mixture of a plurality of polyacids. For example, by using a mixture of polyacids that give different luminescence, a luminescent paper that gives desired luminescence can be made.

  In this embodiment, the polyacid carried on the paper forms an insoluble salt. Since the polyacid is in the form of an insoluble salt, the polyacid is fixed to the paper. For this reason, when it is used for a long time, the polyacid is gradually prevented from detaching from the surface or inside of the paper through contact with hands or the like. In one embodiment, the insoluble salt of the polyacid is insoluble in water. The solubility of the insoluble salt of the polyacid is preferably 0.3 g or less, more preferably 0.1 g or less, and even more preferably 0 so that the insoluble salt of the polyacid can be prevented from being detached from the paper. 0.05 g or less. Solubility refers to the mass of a substance that is soluble in 100 g of water at 25 ° C.

  In one embodiment, the insoluble salt of the polyacid is a salt of a polyacid anion with a metal cation having a valence of 2 or more, or a salt of a polyacid anion and an organic cation. These salts are known to have a relatively low solubility in water.

  As the metal cation having a valence of 2 or more, alkaline earth metal ions such as calcium ion, strontium ion, or barium ion, periodic table group 4 element ions such as zirconium ion, and periodic table such as aluminum ion Examples include ions of group 13 elements.

Examples of the organic cation include organic ammonium ions such as tetramethylammonium ion or formamidinium ion, or organic phosphonium ions such as tetramethylphosphonium ion. In the present specification, the ammonium ion (NH 4 ⁺ ) is an inorganic cation.

The amount of the polyacid insoluble salt supported on the paper is not particularly limited, but is preferably 0.01 mg or more per 1 cm ² , more preferably 0.03 mg or more, and More preferably, it is 1 mg or more. On the other hand, it is preferably 10 mg or less per 1 cm ² , more preferably 3 mg or less, and even more preferably 1 mg or less. The amount of the insoluble salt of the polyacid can be appropriately adjusted according to the thickness of the paper and the application.

(Additive)
In one embodiment, the paper carrying the insoluble salt of polyacid may further carry an additive. For example, an additive may be supported in a fiber matrix constituting paper. Examples of the additive include, but are not limited to, a binder (binder), a light emitting material, and a dielectric compound described below.

  In one embodiment, the paper may further carry a binder (binder) that improves the bondability between the paper and the polyacid. As the binder, for example, a hydrophilic compound can be used. The hydrophilic compound is not limited, but a gelling agent such as gelatin or a polymer compound such as ethyl cellulose or polyvinyl alcohol can be used. Moreover, a lipophilic compound can also be used as a binder. Examples of the oleophilic binder include fluororubber, and a specific example is a fluororubber adhesive (Perflon Paint, manufactured by Haruna). Lipophilic binders such as fluororubber can be added to paper after being diluted with a solvent such as methyl ethyl ketone.

  In order to further improve the binding property, in one embodiment, a compound having sufficient viscosity is used as the binder. For example, when the binder is a (20/3) mass% aqueous solution, the viscosity of the aqueous solution is preferably 0.1 Pa · s or more, more preferably 0.5 Pa · s or more, and 1.0 Pa -More preferably, it is s or more. There is no particular upper limit, but it is, for example, 100 Pa · s or less. The viscosity of the aqueous binder solution can be measured according to JIS K 6503: 2001.

The amount of the binder carried on the paper is not particularly limited, but is preferably 0.01 μg or more per 1 cm ² , more preferably 0.03 μg or more, and 0.1 μg or more. More preferably. On the other hand, it is preferably 1 mg or less per 1 cm ² , more preferably 0.1 mg or less, further preferably 10 μg or less, and particularly preferably 1 μg or less. The amount of the binder can be appropriately adjusted according to the thickness of the paper.

  In one embodiment, as will be described in detail in Embodiment 2, the paper may further carry an EL light-emitting material other than polyacid. For example, the paper may carry both the polyacid and the inorganic dispersed phosphor. Such a paper can be used as a light-emitting paper that provides multicolor light emission. According to such a configuration, it is easy to realize a light emitting paper that gives white light emission. For this reason, such luminescent paper is expected to be applied to display materials.

  In one embodiment, the paper may further carry the dielectric compound described in detail in the third embodiment. By further supporting the dielectric compound, it is expected that the breakdown voltage at which dielectric breakdown of the light emitting layer occurs when used as light emitting paper is increased.

(Light emitting element)
Paper carrying an insoluble salt of a light emitting polyacid can be used as a light emitting layer of a light emitting element. Hereinafter, the paper carrying the insoluble salt of the luminescent polyacid is referred to as the luminescent paper according to this embodiment. A light emitting element using the light emitting paper according to this embodiment is referred to as a light emitting element according to this embodiment.

  EL elements that give flat light emission are expected as display materials, and the development competition is intensifying worldwide. Organic EL elements and inorganic EL elements are known as EL elements that give planar light emission. The light emitting device according to the present embodiment is structurally simpler than the organic EL device, and does not require complicated operations such as vacuum deposition for manufacturing, and thus has an economic advantage. Further, as a high-performance inorganic EL element, a dispersion type EL element mainly using a zinc sulfide-based phosphor is known, but the obtained light emission is mainly limited to green, or a zinc sulfide-based phosphor. It has a problem that it is sensitive to humidity and easily decomposed. On the other hand, the luminescent paper according to the present embodiment has an advantage that it is stable with respect to water and humidity in a use environment, and an environmental load is small because an aqueous solvent can be used during production. Further, there is an advantage that a polyacid can be freely selected according to the purpose such as a desired emission color.

  In order to achieve high-efficiency EL emission, it is important that the polyacid can be fixed in the gaps between the fibers at high density. In this regard, in the luminescent paper according to the present embodiment, the polyacid can be fixed in the fiber at a high density by insolubilizing the polyacid in the fiber matrix. Further, since the fiber itself acts as a dielectric insulator, it is not essential to provide an insulating film such as polyester. For example, for example, the dielectric constant of cellulose is approximately 6 at 1000 Hz or less. Furthermore, the thickness of the light emitting layer can be easily controlled by adjusting the thickness of the paper used as the material. As described above, the light-emitting element according to this embodiment has high performance and can be easily manufactured, so that it can be expected to be produced at a low cost.

  Below, the light emitting element which concerns on this embodiment is demonstrated with reference to FIG. The light emitting element 300 according to the present embodiment includes a light emitting paper 310 and a pair of electrodes 320 that sandwich the light emitting paper 310.

The luminescent paper 310 is a paper carrying an insoluble salt of a luminescent polyacid as described above. The luminescent paper 310 may contain a plurality of types of polyacids, and the luminescent color can be changed by combining a plurality of types of polyacids. For example, [EuW ₁₀ O ₃₆ ] ^9- can be used to provide red emission. [TbW ₁₀ O ₃₆ ] ^9- can also be used to give green light emission. Further, by combining these, light emission of a color in which red and green are mixed can be given.

  The thickness of the luminescent paper 310 is not particularly limited as long as desired light emission can be obtained. In order to prevent the light emitting paper 310 from being defective, the thickness of the light emitting paper 310 is preferably 10 μm or more, and more preferably 30 μm or more. Further, since the applied voltage required for light emission tends to increase as the luminescent paper 310 becomes thicker, the thickness of the luminescent paper 310 is preferably 200 μm or less, and more preferably 130 μm or less.

  The electrode 320 is made of a conductive material, and the type is not particularly limited. In order to extract light, at least one of the pair of electrodes 320 is preferably a transparent electrode. Examples of the transparent electrode include an ITO electrode.

  The light emitting element 300 may include components other than the light emitting paper 310 and the electrode 320. For example, the light emitting element 300 may include a sealing material (not shown) that seals the element. The light emitting element 300 may include an insulating layer (not shown) between the light emitting paper 310 and the electrode 320. However, the light-emitting element 300 exhibits good light-emitting performance without having an insulating layer between the light-emitting paper 310 and the electrode 320. This is considered to be because the luminescent paper 310 plays a role as an insulating layer. That is, in one embodiment, the luminescent paper 310 is in direct contact with at least one of the pair of electrodes 320, preferably both.

  When a pulse voltage power source 330 is connected between the pair of electrodes 320 and a pulse voltage is applied, the luminescent paper 310 emits light. In one embodiment, a voltage of about 100-1500 V is applied between both electrodes. In one embodiment, a pulse voltage having a frequency of about 20 to 400 hertz is applied.

  The light emitting element 300 according to this embodiment can be easily manufactured by sandwiching the light emitting paper 310 between the pair of electrodes 320. In one embodiment, the luminescent paper 310 is sandwiched between a pair of electrodes 320, and the electrode 320 is fixed with a spring clip 340, whereby the light emitting element 300 is manufactured. Thus, the light emitting device 300 according to this embodiment can be easily and inexpensively manufactured.

(Method for producing paper carrying insoluble salt of polyacid)
Paper carrying a polyacid can be produced by applying a polyacid aqueous solution to the paper. However, it is required to increase the concentration of the polyacid salt fixed inside the paper, for example, in order to produce a luminescent paper that gives high luminescence intensity. However, there is a limit to the concentration of polyacid obtained by simply applying a polyacid aqueous solution to paper.

  Therefore, in the present embodiment, a coating step of applying a coating solution containing polyacid to paper, and a coating solution containing a metal cation having a valence of 2 or more or an organic cation is applied to paper. Thus, a paper carrying the insoluble salt of the polyacid is produced using a precipitation step of precipitating the insoluble salt of the polyacid. By such a method, a paper carrying a high concentration of an insoluble salt of polyacid can be produced. This manufacturing method (hereinafter simply referred to as the manufacturing method according to the present embodiment) will be described in detail with reference to the flowchart of FIG.

  In the coating step (S210), a coating solution containing a polyacid is applied to paper. The polyacid and paper are as already described. A coating solution containing a polyacid can be prepared by dissolving the polyacid in a solvent. The type of the solvent is not particularly limited as long as the polyacid can be dissolved. Examples of solvents include water and other polar solvents. In one embodiment, from the viewpoint of easy handling, the coating solution containing a polyacid is an aqueous solution of a polyacid.

  A polyacid in the form of a salt with an alkali metal salt such as sodium or potassium, or a monovalent cation such as an ammonium salt has a relatively high solubility in water. From such a viewpoint, it is preferable that the aqueous solution of the polyacid contains an alkali metal salt or an ammonium salt of the polyacid. In one embodiment, the aqueous solution of polyacid contains an alkali metal salt of polyacid.

Specific examples of such polyacids include Na ₉ [EuW ₁₀ O ₃₆ ] · 32H ₂ O, K ₃ Na ₄ H ₂ [TbW ₁₀ O ₃₆ ] · 20H ₂ O, Na ₇ H ₁₉ {[Eu ₃ O _{(OH) 3 (H 2 O} ) 3] 2 Al 2 (Nb 6 O 19) 5} · 47H 2 O, Na 7 H 19 {[Tb 3 O (OH) 3 (H 2 O) 3] 2 Al 2 (Nb ₆ O ₁₉ ) ₅ } · 47H ₂ O, K ₁₅ H ₃ [Eu ₃ (H ₂ O) ₃ (SbW ₉ O ₃₃ ) (W ₅ O ₁₈ ) ₃ ] · 25.5H ₂ O, K ₁₅ H ₃ [Tb ₃ (H ₂ O) ₃ (SbW ₉ O ₃₃ ) (W ₅ O ₁₈ ) ₃ ] · 25.5H ₂ O, [NH ₄ ] ₁₂ H ₂ [Eu ₄ (H ₂ O) ₁₆ (MoO ₄ ) (Mo ₇ O ₂₄ ) ₄ ] · 13H ₂ O, [NH ₄ ] ₁₂ H ₂ [Tb ₄ (H ₂ O) ₁₆ (MoO ₄ ) (Mo ₇ O ₂₄ ) ₄ ] · 13H ₂ O, [Eu ₂ (H ₂ O) ₁₂ ] [Mo ₈ O ₂₇ ] · 6H ₂ O, K ₂ H ₃ {[Eu (H ₂ O) ₄ ] ₃ [(GeTi ₃ W ₉ O ₃₇ ) ₂ O ₃ ]} · 13H ₂ O, K ₁₂ [EuP ₅ W ₃₀ O ₁₁₀ ] · 54H ₂ O, [Eu (H _{2 O) 8] 2 [V} 10 O 28] · 8H 2 O, Na 3 H 6 [CrMo 6 O 24] · 8H 2 O, K 6 Na 2 [MnW 6 O 24] · 12H 2 O, K 6 [ _{MnMo 6 O 32] · 6H 2} O, Na 12 [Mn (Nb 6 O 19) 2] · 50H 2 O , and the like.

  The application method is not particularly limited, and for example, a method of applying a glass solution after dropping the application solution, a method of applying with a brush, a method of spraying the application solution, or a method of discharging the application solution with an inkjet device, etc. Can be mentioned. Moreover, you may apply | coat by immersing paper in a coating liquid.

  In one embodiment, application is performed using a glass rod according to the method shown in FIG. That is, the polyacid coating solution in the beaker 110 is dropped onto the paper 130 with the pipette 120 and applied to the entire paper surface with the glass rod 140. Thus, the paper 150 coated with the polyacid coating solution is obtained.

  In the precipitation step (S220), a coating solution containing a metal cation having a valence of 2 or more or an organic cation is applied to paper. Polyacids in the form of salts with divalent or higher valent metal cations or organic cations have a relatively low solubility in water. Therefore, ion exchange occurs when a coating solution containing a metal cation having a valence of 2 or more or an organic cation is applied to a paper carrying an alkali metal salt or ammonium salt of a polyacid. The polyacid becomes insoluble. For this reason, in the precipitation step (S220), the insoluble salt of the polyacid can be precipitated and the insoluble salt of the polyacid can be fixed inside the paper.

  A coating solution containing a metal cation having two or more valences or an organic cation can be prepared by dissolving a compound containing these ions in a solvent. The type of the solvent is not particularly limited as long as the compound can be dissolved. Examples of solvents include water and other polar solvents. In one embodiment, an aqueous solution containing a metal cation having 2 or more valences or an organic cation is used from the viewpoint of ease of handling. However, any solvent may be used as long as it is a solvent in which a salt of polyacid generated by ion exchange is difficult to dissolve.

  The compound containing a metal cation having a valence of 2 or more is not particularly limited, and examples thereof include metal halides such as calcium chloride, barium chloride, aluminum chloride, and zirconium chloride. Moreover, a metal hydroxide or a metal nitrate can also be used. Moreover, it does not specifically limit as a compound containing an organic cation, A hydroxide, a halide, etc. are mentioned. Specific examples include alkylammonium hydroxides such as tetramethylammonium hydroxide or alkylammonium halides such as tetraethylammonium bromide.

  The amount of divalent or higher valent metal cation or organic cation contained in the coating solution can be determined according to the type and amount of polyacid. Specifically, it is preferable to apply a metal cation having a valence of 2 or more or an organic cation in such an amount that ion exchange sufficiently proceeds. In one embodiment, the molar ratio of ions and polyacid applied to paper (a metal cation having a valence of 2 or more, or an organic cation: polyacid) is preferably 1: 1 or more, The ratio is more preferably 4: 1 or more, and more preferably 16: 1 or more. There is no particular upper limit, and it can be, for example, 32: 1 or less.

  The coating method of the coating liquid containing a metal cation having a valence of 2 or more or an organic cation is not particularly limited and can be applied in the same manner as in the coating step (S210).

  The paper carrying the insoluble salt of the polyacid can be produced by the above steps. The obtained paper can be further dried. The drying method is not particularly limited, and it may be dried at room temperature or in a heated atmosphere. For example, the drying temperature can be 15 ° C. or higher and 120 ° C. or lower. Moreover, you may dry in air | atmosphere and may dry under reduced pressure. The drying time can be appropriately selected according to the drying method, the thickness of the paper, and the like. For example, when paper having a thickness of about 100 μm is used and dried at room temperature in the air, the drying time can be, for example, 12 hours or more and 120 hours or less.

  As described above, the paper carrying the insoluble salt of polyacid may further carry a binder (binder). In this case, the binder coating solution can be applied to the paper before the coating step (S210) so that more polyacid is supported. The binder coating solution can be prepared by dissolving the binder in a solvent. The type of the solvent is not particularly limited as long as the binder can be dissolved. Examples of solvents include water and other polar solvents. In one embodiment, from the viewpoint of ease of handling, the binder coating solution is an aqueous solution of a binder. The method for applying the binder coating solution is not particularly limited, and it can be applied in the same manner as in the coating step (S210).

  Further, as described above, the paper carrying the insoluble salt of the polyacid may further carry an EL light emitting material other than the polyacid. In this case, the EL light-emitting material can be supported on the paper by applying the light-emitting material coating liquid to the paper. The luminescent material coating solution can be prepared by dissolving or dispersing the EL luminescent material in a solvent. The type of the solvent is not particularly limited as long as the light emitting material can be dissolved or dispersed. Examples of the solvent include polar solvents such as water or alcohol. A resin such as ethyl cellulose may be further added to the coating solution so that the luminescent material is easily dispersed in the coating solution. The application method of the light emitting material application liquid is not particularly limited, and it can be applied in the same manner as in the application step (S210). The timing for applying the light emitting material coating solution is not particularly limited, and may be, for example, before the coating step (S210) or after the deposition step (S220).

  As described above, the paper carrying the insoluble salt of polyacid may further carry a dielectric compound. In this case, the dielectric compound can be supported on the paper by applying the dielectric compound coating liquid to the paper. The dielectric compound coating solution can be prepared by dissolving or dispersing the dielectric compound in a solvent. The type of the solvent is not particularly limited as long as the dielectric compound can be dissolved or dispersed. Examples of the solvent include water, a ketone solvent such as N-methylpyrrolidone, and other polar solvents. A resin such as ethyl cellulose may be further added to the coating solution so that the dielectric compound is easily dispersed in the coating solution. The coating method of the dielectric compound coating solution is not particularly limited, and can be applied in the same manner as in the coating step (S210).

  As described above, the paper carrying the insoluble salt of polyacid may further carry additives such as a binder, a light emitting material, and a dielectric compound. In this case, the coating order of the polyacid coating solution, the binder coating solution, the light emitting material coating solution, and the dielectric compound coating solution is not limited as long as the effect is not impaired. Moreover, it is not essential to apply these coating liquids separately, and one coating liquid may contain two or more materials. As an example, a coating solution containing a polyacid and a binder may be prepared, and this coating solution may be applied to paper in the coating step (S210). As another example, a coating solution containing a polyacid and a dielectric compound may be prepared, and this coating solution may be applied to paper in the coating step (S210).

  The paper carrying the insoluble salt of polyacid produced in this way uniformly carries the polyacid over the polyacid carrying portion, which is at least a part of the paper, for the above-described production method. Such paper can exhibit stable performance when used in a device such as a light emitting element, particularly in a surface light emitting device. For example, in one embodiment, the paper carrying the polyacid carries the polyacid at a uniform concentration across the thickness direction.

  In one embodiment, the luminescent paper carrying the luminescent polyacid carries the polyacid at a uniform concentration over the thickness direction. In this case, the emission intensity of the paper when irradiated with excitation light of a predetermined intensity is the same on the front surface and the back surface. Specifically, in one embodiment, the emission intensity observed when a predetermined portion of paper is irradiated with ultraviolet rays from one side of the paper, and when the same portion is irradiated with ultraviolet rays from the other side of the paper There is no significant difference between the observed emission intensity.

  According to the method of Embodiment 1, the polyacid can be fixed inside the paper. A light-emitting element using a light-emitting layer having a structure in which a light-emitting material such as polyacid is fixed inside paper can emit light at a relatively low applied voltage, and effectively suppresses breakdown. Can do. Moreover, according to the method of Embodiment 1, compared with the case where the coating liquid containing a polyacid is simply applied, the polyacid can be fixed inside the paper at a high density. Therefore, it is possible to improve the light emission intensity of a light emitting element using this paper as a light emitting layer.

  In addition, by applying the method of Embodiment 1, a polyacid having functionality such as antiviral action or antibacterial action can be fixed inside the paper at a high concentration. In this way, the functionality of the paper can be further improved.

[Embodiment 2]
In the paper having a luminescent material and having luminescent properties, the luminescent material is not limited to the luminescent polyacid. In the luminescent paper described in Embodiment 1, the insoluble salt of polyacid is mainly fixed inside the paper, but a part thereof is also present on the surface of the paper. And there is no doubt that the polyacid present on the surface of the paper also contributes to light emission. From this, the inventor of the present application considered that the luminescent paper can be similarly produced even when the phosphor other than the polyacid is supported on the paper.

  The paper according to the second embodiment has the same configuration as that of the first embodiment except that an EL light-emitting material (excluding the polyacid) is supported instead of the polyacid, and thus redundant description is omitted. The EL light emitting material is not particularly limited, and conventionally known materials can be used. In the present embodiment, a light emitting material is supported in paper fibers. For example, a light emitting material is supported in a matrix of fibers constituting paper. For this reason, in one embodiment, an inorganic dispersion type phosphor that is known to emit light even in a dispersed state is used as the EL light emitting material. As the inorganic dispersion type phosphor, for example, a phosphor in which ZnS, CdSe, CdTe, ZnSe or the like is used as a base, and a rare earth such as cerium or europium, or a transition metal such as copper, manganese, gold, or silver ions is doped. Yes. In one embodiment, a zinc sulfide-based phosphor such as ZnS: Cu, which is known to have particularly high light emission performance, is used. The paper according to Embodiment 2 can be used as light-emitting paper. For example, the paper can be used as the light-emitting paper 310 of the light-emitting element 300 described in Embodiment 1. The paper according to the second embodiment may further carry an additive as in the first embodiment. For example, the paper may further carry a binder, a dielectric compound, or both a binder and a dielectric compound. Good.

The amount of the EL light emitting material carried on the paper is not particularly limited, but is preferably 0.01 mg or more per 1 cm ² , more preferably 0.03 mg or more, and 0.1 mg or more. More preferably. On the other hand, it is preferably 10 mg or less per 1 cm ² , more preferably 3 mg or less, and even more preferably 1 mg or less. The amount of the EL light emitting material can be appropriately adjusted according to the thickness of the paper and the application.

  A paper manufacturing method according to Embodiment 2 will be described with reference to the flowchart of FIG. In step S1010, a luminescent material coating solution containing an EL luminescent material (excluding polyacid) is applied to paper. The luminescent material coating solution can be prepared by dissolving or dispersing the EL luminescent material in a solvent. The type of the solvent is not particularly limited as long as the light emitting material can be dissolved or dispersed and the light emitting material does not decompose. For example, when ZnS: Cu, Cl is used as the light emitting material, an alcohol solvent such as methanol can be used. A resin such as ethyl cellulose may be further added to the coating solution so that the luminescent material is easily dispersed in the coating solution. In step S1020, the paper after the application of the light emitting material application liquid is dried. The drying process can be performed as described in the first embodiment. In this way, paper carrying the electroluminescent light emitting material can be manufactured.

[Embodiment 3]
In an EL light emitting device, it is important that breakdown does not easily occur. Breakdown is a phenomenon of dielectric breakdown that occurs mainly when the applied voltage is raised, and it means that the light emission becomes unstable or the element is damaged. The inventor of the present application has further found that by supporting the dielectric compound, the pressure resistance against the applied voltage of the paper carrying the luminescent material is improved.

  The paper according to Embodiment 3 carries an EL light emitting material and a dielectric compound. For example, a dielectric compound is supported in a matrix of fibers constituting paper. The EL light-emitting material is not particularly limited, and may be a water-soluble salt of a luminescent polyacid, or an insoluble salt of the luminescent polyacid described in Embodiment 1, or in Embodiment 2. Other EL light emitting materials described may be used. As described in the second embodiment, the paper according to the third embodiment may carry a plurality of light emitting materials. The paper according to the third embodiment has the same configuration as that of the first embodiment except that the light-emitting material is not limited to the insoluble salt of polyacid and carries a dielectric compound, and therefore, overlapping description. Is omitted.

  A dielectric compound refers to a compound having a higher relative dielectric constant than paper. Specifically, the relative dielectric constant of the dielectric compound is higher than the relative dielectric constant of the light-emitting material and paper not carrying the dielectric. For example, in the case of using vegetable fiber paper, the relative dielectric constant is about 2.0 to 2.5. Therefore, the relative dielectric constant of the dielectric compound is preferably 2.5 or more, and is 4.0 or more. More preferably, it is more preferably 6.5 or more, and particularly preferably 100 or more. In one embodiment, the dielectric constant of the dielectric compound is higher than that of the fibers constituting the paper. For example, when plant fiber paper is used, the relative dielectric constant of cellulose (kraft paper), which is the main component of the fiber, is about 6, and therefore the relative dielectric constant of the dielectric compound is preferably 6.5 or more. 100 or more is more preferable. Specific examples of the dielectric compound include cyanoethyl cellulose (with a relative dielectric constant of about 7 to 15, the larger the number of cyanoethyl substituents, the higher the relative dielectric constant) or barium titanate (with a relative dielectric constant of about 5000). ) And the like. In one embodiment, the dielectric compound is solid at 25 ° C. in the atmosphere so that the paper according to Embodiment 3 can be easily handled. In the present specification, the relative dielectric constant refers to a value at a frequency of 1000 Hz.

  The paper according to Embodiment 3 can be manufactured by a step of applying a luminescent material coating solution to paper and a step of applying a dielectric compound coating solution to paper. The order of these steps is not particularly limited. The step of applying the luminescent material coating liquid to the paper can be performed by applying a coating liquid prepared by dissolving or dispersing the luminescent material in a solvent to the paper, as in the second embodiment. Similarly to Embodiment 1, after applying a coating solution prepared by dissolving a light emitting material in a solvent to paper, a coating solution for insolubilizing the light emitting material may be applied to paper. In addition, the step of applying the dielectric compound coating liquid to paper is performed by applying a coating liquid prepared by dissolving or dispersing the dielectric compound in a solvent to paper as described in the first embodiment. Can do.

  The paper according to Embodiment 3 can be used as light-emitting paper, and can be used as the light-emitting paper 310 of the light-emitting element 300 described in Embodiment 1, for example.

[Example 1-1]
Paper cut to a size of 4.5 cm × 10 cm (manufactured by Miyoshi Paper Co., Ltd., Dialite 25, pulp mass 25 g / m ² , thickness 40-50 μm) was prepared. Further, gelatin as a binder (manufactured by Konica, TS-361 PC, 14 mg) and Na ₉ [EuW ₁₀ O ₃₆ ] .32H ₂ O (manufactured by MO device, 2 g) as a luminescent material were ultrasonically stirred. Was dissolved in water (100 mL) to prepare a coating solution. Na ₉ [EuW ₁₀ O ₃₆ ] .32H ₂ O is a water-soluble polyacid having the property of emitting red light when irradiated with ultraviolet rays. Na ₉ [EuW ₁₀ O ₃₆ ] .32H ₂ O is a white solid, and its solubility in water at room temperature is about 50 g / L. Sample A was produced by apply | coating the obtained coating liquid (1 mL) to the whole surface of paper, and making it air dry at room temperature. The coating solution was applied according to the method shown in FIG.

[Example 1-2]
BaCl ₂ · 2H ₂ O (manufactured by Kanto Chemical Co., Inc., 0.3 g) was dissolved in water (10 mL) to prepare a coating solution. This coating liquid (1 mL) was applied to the entire surface of Sample A obtained according to Example 1-1, and air-dried at room temperature to prepare Sample B. The coating solution was applied according to the method shown in FIG.

[Example 1-3]
A coating solution was prepared by dissolving cyanoethyl cellulose (manufactured by Unitech Corp., 60 mg) as a dielectric compound in N-methyl-2-pyrrolidone (10 mL) by ultrasonic stirring. This coating solution (1 mL) was applied to the entire surface of Sample A obtained according to Example 1-1, and air-dried at room temperature to prepare Sample C. The coating solution was applied according to the method shown in FIG.

[EL measurement]
A light emitting element was prepared using each of the samples A to C, which were light emitting papers, and the EL light emission characteristics were evaluated for each. Specifically, as shown in FIG. 3, the luminescent paper 310 (samples A to C) is sandwiched between glass electrodes 320 (commercially available ITO transparent glass electrodes, In ₂ O ₃ / SnO ₂ ), and commercially available spring clips 340 are used. The light emitting element 300 was manufactured by sandwiching. Then, EL emission emitted from the luminescent paper 310 when a voltage was applied between the electrodes 320 using the pulse voltage power source 330 was observed.

  FIG. 4 shows a block diagram of the EL measurement system. The EL emission from the light emitting element 300 is measured by a spectroscope 410 (manufactured by Nikon) -photomultiplier tube 420 (manufactured by Hamamatsu Photonics) -boxcar integrator 430 (manufactured by NF Circuit Design Block) -recorder 440. And monitored by an oscilloscope 450.

By applying a pulse voltage between the two ITO electrodes, red light emission derived from Na ₉ [EuW ₁₀ O ₃₆ ] .32H ₂ O was observed. The emission intensity increases exponentially when the application of one cycle of pulse voltage is started, and is maximized immediately before the application of one cycle of pulse voltage is completed. Decayed functionally. FIG. 5 shows a potential waveform of a rectangular pulse voltage applied to the light emitting element 300 having a duty ratio of 1: 4, a frequency of 200 Hz, and a negative high voltage (−0.4 kV) with respect to the ground, and the pulse voltage. The EL luminescence intensity observed when applied to. FIG. 5 shows the measurement results for sample B, but the waveforms indicating the same emission intensity were also obtained for samples A and C. As shown in FIG. 5, the EL emission intensity reached its maximum 1 ms after the start of voltage application. The EL emission intensity signal at this time, using the Boxcar integrator 430, the gate width 5 .mu.s, window width 5 ms, the sample point 1024 was measured under the conditions of averaging count ^{2 4.}

  In all of the samples A to C, EL light emission suddenly occurred at a certain voltage, and then rapidly increased as the applied voltage increased. At a sufficiently high voltage, microplasma was generated and the light emission disappeared after breakdown. The voltage at which EL emission rises (threshold voltage) is around −0.3 kV, and the emission intensity increased exponentially as the applied voltage was increased. On the other hand, the breakdown voltage at which the generation of microplasma is observed is -0.45 kV in sample A and -0.6 kV in sample B, while -1.0 kV in sample C. Met. Thus, compared to sample A, the pressure resistance improved slightly in sample B, and the pressure resistance significantly improved in sample C. The threshold voltage and the breakdown voltage value were measured by sequentially increasing or decreasing the observed EL emission intensity and the applied voltage, and plotting the EL emission intensity and the applied voltage.

In order to observe EL light emission using sample B, an aging process by applying a low voltage (-0.1 kV to -0.2 kV), that is, applying a low voltage for a certain time before causing EL light emission by a high voltage. It was necessary to keep it. This was thought to be because crystal water contained in the polyacid through the aging process changed its orientation due to polarization in the polyacid crystal because of its large dielectric constant (approximately 80). As the crystal structure of [EuW ₁₀ O ₃₆ ] ^9- alkaline earth metal salt, NaSr ₄ [EuW ₁₀ O ₃₆ ] .34H ₂ O having 34 crystal waters is known (Toshihiro Yamase, Tomoji Ozeki , Ueda Shinta, International Crystallographic Journal, C49, 1572-1574, 1993). From this, it is expected that the polyacid barium salt having barium having an ionic radius larger than that of strontium contains 34 or more crystal waters. The formation of the barium salt increases both the molecular diameter of the polyacid and the particle diameter of the polyacid crystal. For this reason, water molecules having a small molecular diameter that have been oriented by the crystal field in the crystal of the polyacid are polarized by application of voltage because of their electric dipoles. Accordingly, it was estimated that a predetermined relaxation time was required for the crystal water of the polyacid barium salt having a large molecular diameter and particle diameter to be reoriented and polarized. Thus, it is considered that the pressure resistance is improved as a result of the reorientation of part or all of the crystal water of the polyacid barium salt through the aging process and the increase in the dielectric constant of the polyacid salt.

FIG. 6 shows an EL emission spectrum obtained when a pulse voltage of −0.31 kV was applied to the sample B. The spectrum shows the emission characteristic of Eu ³⁺ . Specifically, emission peaks near 592, 618, 650, and 695 nm are attributed to transitions of ⁵ D ₀ → ⁷ F ₁ , ⁷ F ₂ , ⁷ F ₃ , and ⁷ F ₄ , respectively.

By comparing the emission intensity of the ⁵ D ₀ → ⁷ F ₂ transition in the vicinity of 618 nm, which is the strongest emission peak in the emission spectrum, the relative intensity of emission for samples A to C was calculated. The obtained results are shown in Table 1.

  As is clear from the results of Table 1, the threshold voltage of EL emission hardly changed between samples A to C. On the other hand, in Sample B carrying an insoluble polyacid alkaline earth metal salt, the EL emission intensity increased as compared to Sample A.

In Example 1-2, it was observed that the EL emission intensity was increased by increasing the barium chloride concentration in the coating solution. Further, the EL emission intensity increased with increasing barium chloride concentration and then saturated until the molar ratio of barium chloride to be applied to the polyacid was 16: 1 or more. In Example 1-2, similar results were obtained when calcium chloride or strontium chloride was used instead of barium chloride. This result is generally consistent with the molar ratio of strontium ions to polyacid anions of 4: 1 in NaSr ₄ [EuW ₁₀ O ₃₆ ] .34H ₂ O. In other words, since the ion exchange reaction occurs in the entire gap between the paper fibers, an alkali in an amount sufficient for the molar ratio of the alkaline earth metal ion to the polyacid to exceed 4: 1 in order to proceed the ion exchange reaction completely. Earth metal ions are considered necessary. Thus, this experimental result supports that the ion exchange reaction reaches the entire gap of the paper pulp.

  Thus, according to Example 1-2 in which the polyacid was immobilized by applying a coating solution that insolubilizes the polyacid after the coating solution containing the soluble salt of the polyacid was applied to the paper, It was confirmed that the EL emission intensity was improved as compared with Example 1-1 in which a coating solution containing an acid-soluble salt was applied to paper. This indicates that the method of Example 1-2 increases the amount of polyacid supported on the resulting paper as compared to the method of Example 1-1.

  Further, as in sample C, an increase in breakdown voltage (increase in breakdown voltage) is observed when a part of the periphery of the polyacid is occupied by cyanoethyl cellulose having a high dielectric constant in the paper. In this way, it is shown that the paper carries a dielectric compound such as cyanoethyl cellulose, which broadens the range of applied voltage, stabilizes the EL element, and alleviates the need for strict voltage control. It was.

[Example 2]
Paper cut to a size of 4.5 cm × 10 cm (manufactured by Miyoshi Paper Co., Ltd., Dialite 25, pulp mass 25 g / m ² , thickness 40-50 μm) was prepared. In addition, ZnS: Cu, Cl (manufactured by OSRAM-Sylvania, particle size 10-100 μm, 2.75 g) as an inorganic dispersion type phosphor, and ethyl cellulose (manufactured by Nisshin Kasei Co., Ltd., ethyl cellulose EC vehicle EC-300FTP) , 5 mL) was dispersed in methanol (100 mL) by ultrasonic stirring to prepare a coating solution. Sample D was produced by apply | coating the obtained coating liquid (1 mL) to the whole surface of paper, and making it air dry at room temperature. The coating solution was applied according to the method shown in FIG.

  In the same manner as in Example 1, a light emitting element was manufactured using Sample D, and EL light emission characteristics were evaluated. When a voltage was applied, green light emission of ZnS: Cu, Cl was observed on Sample D. FIG. 7 shows the light emission intensity observed when a negative high voltage (−0.4 kV) rectangular wave voltage with respect to the ground is applied to the light emitting element. Unlike Example 1, the emission intensity increased rapidly at the same time as the application of the pulse voltage of one cycle was started, and then attenuated even during the application of the pulse voltage of one cycle. Also, the emission intensity rapidly increased again at the end of the application of the pulse voltage of one cycle, and then the emission intensity was attenuated. This change with time can be understood as follows. That is, at the start of application of the pulse voltage, it is considered that EL emission is caused by excitation of the emission center of the phosphor by the large kinetic energy of electrons accelerated to a large potential gradient in the sample D. At the end of the application of the pulse voltage, it is considered that a reverse bias (reverse high voltage) is generated by the electrons trapped in the phosphor layer, and the light emission center is excited again, thereby causing EL emission.

  FIG. 8 shows an EL emission spectrum observed 1 millisecond after the end of applying one cycle of the pulse voltage when a pulse voltage of −0.24 kV was applied to the light emitting element. As shown in FIG. 8, a wide emission peak in the range of about 470 to 480 nm corresponding to green, characteristic of ZnS: Cu, Cl, was observed. As described above, it was confirmed that a luminescent paper carrying the inorganic dispersed phosphor can be obtained by applying the coating liquid of the inorganic dispersed phosphor to the paper.

[Example 3]
Paper cut to a size of 4.5 cm × 10 cm (manufactured by Miyoshi Paper Co., Ltd., Dialite 25, pulp mass 25 g / m ² , thickness 40-50 μm) was prepared. Further, gelatin as a binder (manufactured by Konica, TS-361 PC, 14 mg) and Na ₉ [EuW ₁₀ O ₃₆ ] .32H ₂ O (manufactured by MO device, 2 g) as a luminescent material were ultrasonically stirred. Was dissolved in water (100 mL) to prepare a coating solution. The resulting coating solution (1 mL) was applied to the entire surface of the paper and allowed to air dry at room temperature for 1 day.

Next, BaCl ₂ .2H ₂ O (0.25 g) was dissolved in water (10 mL) to prepare a coating solution. The obtained coating solution (1 mL) was applied to the entire surface of the paper after applying and drying Na ₉ [EuW ₁₀ O ₃₆ ] .32H ₂ O, and air-dried at room temperature for another day.

Next, ZnS: Cu, Cl (Osram-Sylvania, particle size 10-100 μm, 0.3 g) as an inorganic dispersion type phosphor, BaTiO ₃ (0.3 g) as a dielectric compound, and binder Of ethyl cellulose (Nisshin Kasei Co., Ltd., ethyl cellulose EC vehicle EC-300FTP, 5 mL) was dispersed in methanol (100 mL) by ultrasonic stirring to prepare a coating solution. The obtained coating solution (1 mL) was applied to the entire surface of the paper after the BaCl ₂ was applied and dried, and then air-dried at room temperature for another day. Sample E was thus prepared. Each coating solution was applied according to the method shown in FIG.

In the same manner as in Example 1, a light-emitting element was manufactured using Sample E, and EL light-emitting characteristics were evaluated. FIG. 9 shows an EL emission spectrum when a pulse voltage of −0.36 kV is applied to the light-emitting element. As shown in FIG. 9, the obtained emission spectrum includes a spectrum corresponding to green emission from ZnS: Cu, Cl, a spectrum corresponding to red emission from [EuW ₁₀ O ₃₆ ] ⁹⁻ , and Was included independently.

  Thus, by applying a coating liquid containing a light emitting polyacid to paper and coating a paper containing an inorganic dispersion type phosphor on paper, the light emitting polyacid and the inorganic dispersion type phosphor It was confirmed that a luminescent paper carrying s was obtained. From the light emitting element using the paper carrying the light emitting polyacid and the inorganic dispersed phosphor as the light emitting layer, the light emitting polyacid and the inorganic dispersed phosphor do not interfere with each other, and the light emitting property is obtained. It was confirmed that both the light emission derived from the polyacid and the light emission derived from the inorganic dispersed phosphor were observed.

In Example 3, the emission intensity derived from [EuW ₁₀ O ₃₆ ] ^9- can be increased or decreased by increasing or decreasing the concentration of Na ₉ [EuW ₁₀ O ₃₆ ] · 32H ₂ O in the coating solution. all right. Similarly, it has been found that the emission intensity derived from ZnS: Cu, Cl can be increased or decreased by increasing or decreasing the concentration of ZnS: Cu, Cl in the coating solution.

300 Light emitting element 310 Light emitting paper 320 Electrode

Claims (6)

  A paper carrying an insoluble salt of a polyacid, further carrying an electroluminescent light emitting material (excluding polyacid). The paper according to claim 1 , wherein the electroluminescent light emitting material is an inorganic dispersed phosphor. The insoluble salt of the polyacid is a salt of a polyacid anion and a metal cation having a valence of 2 or more, or a salt of a polyacid anion and an organic cation. Or the paper of 2 . The paper according to any one of claims 1 to 3 , further comprising a dielectric compound. And paper according to any one of claims 1 to 4, the light emitting device characterized by comprising a pair of electrodes sandwiching the paper. Applying a coating solution containing polyacid to paper;
A step of precipitating an insoluble salt of polyacid by applying a coating solution containing a metal cation having a valence of 2 or more or an organic cation to the paper;
A method for producing a paper carrying an insoluble salt of a polyacid, characterized by comprising:

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