JP2008024774A - Fluorescent substance sheet and light-emission element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorescent substance sheet having a flexibility and usable under a high temperature environment, and a flexible light-emission element. <P>SOLUTION: The fluorescent substance sheet is provided, which is characterized in a structure that laminar silicate crystalline pieces activated by a rare earth ion are laminated. Further, the laminar silicate crystalline piece has an aligned plane orientation, and a crystalline structure of the laminar silicate crystalline piece is any one of a mica structure, a chlorite structure, a kaolinite structure or a smectite structure. Further, the rare earth ion is the one selected from the group consisting of divalent Eu, divalent Sm, trivalent Ce, trivalent Eu, trivalent Sm and trivalent Tb. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a phosphor sheet and a light emitting device. In detail, it is related with the electroluminescent fluorescent substance sheet and light emitting element which are used for a flat panel display.

One of flat panel displays (FPD) using fine particles and a thin film having a light emitting function is an electroluminescence (EL) display. The electroluminescent phosphor is an electric field excitation type phosphor and includes a dispersion type EL and a thin film type EL. The dispersion type EL has a configuration in which a phosphor powder dispersed in an organic binder having a high dielectric constant is sandwiched between two electrodes at least one of which is transparent. The thin film type EL has a structure in which a transparent conductive film, an insulating layer, an EL light emitting layer, an insulating layer, and a back electrode are sequentially stacked on a substrate by vacuum deposition or sputtering. Since the dispersion type EL does not use a high temperature process in the production process, it has the following features. That is, it is possible to form a flexible panel using a plastic substrate, etc., it is possible to manufacture at a low cost without using a vacuum device, and to emit light by mixing phosphor particles of different emission colors. Color adjustment is easy.
JP 2005-283911 A

  However, the flexible light-emitting element using the dispersion-type EL having the above configuration is difficult to use in a high-temperature environment because the organic binder and the plastic substrate in which the phosphor powder is dispersed are deteriorated by heat.

  To solve this problem, for example, as disclosed in Patent Document 1, a method of reducing deterioration due to heat of an organic binder or a plastic substrate by arranging a member having good heat conductivity on the back surface of an EL display panel has been proposed. However, the organic substance is used as the binder, and cannot be used when the temperature of the external atmosphere is higher than the limit of the heat resistant temperature limit of the organic binder.

  The present invention has been proposed to solve the above-described problems, and an object of the present invention is to provide a phosphor sheet having flexibility and usable in a high-temperature environment, and a flexible light-emitting element. .

  The above problems can be solved by the following configuration and manufacturing method of the present invention.

  That is, the phosphor sheet of the present invention is a phosphor sheet characterized by having a structure in which layered silicate crystal pieces activated by rare earth ions are laminated.

  Here, the phosphor sheet is characterized in that the crystal structure of the layered silicate crystal piece is any one of a mica structure, a chlorite structure, a kaolinite structure, and a smectite structure.

  ADVANTAGE OF THE INVENTION According to this invention, it has a softness | flexibility and can provide the fluorescent substance sheet which can be used in a high temperature environment, and a flexible light emitting element.

  Embodiments of the present invention will be described below.

  The phosphor sheet of the present invention has a structure in which layered silicate crystal pieces activated by rare earth ions are laminated.

Layered silicate crystals that are inorganic crystals are stable and have no structural change even at high temperatures up to 800 ° C. A layered silicate crystal, for example, mica, has a structure in which two layers of SiO ₄ tetrahedrons are connected to each other, and ions (Al ³⁺ , Mg ²⁺ , Fe that take OH groups and octahedral coordination between the layers) ²⁺ etc.). The unit layer having a thickness of about 1 nm composed of the above is bonded by ionic bonding with alkali metal ions or alkaline earth metal ions existing between the unit layers. Compared with the Si—O covalent bond or ionic bond in the unit layer, the ionic bond between the unit layers is very weak, so the mica is easily peeled off in a thin film. Therefore, the layered silicate crystal tends to be a thin film-like crystal piece, and when this crystal piece is deposited innumerably with the plane orientation aligned, a self-supporting film in which the layered silicate crystal piece is bonded by intermolecular force is obtained, and Since the bonding force between the particles is weak and can be easily shifted, the film has flexibility.

  The layered silicate crystal of the present invention may have any structure of mica structure, chlorite structure, kaolinite structure, and smectite structure. Specifically, examples of the mica structure include muscovite, hydrate mica, phlogopite, biotite, lepidite, and the like. In addition, examples of the chlorite structure include chamosite, clinochlore, and stilpnolane. Examples of the kaolinite structure include kaolinite, halloysite, antigolite, chrysotile, and asbestos. Examples of the smectite structure include montmorillonite, prehnite, and fisheye stone (fluoropophyllite).

  Examples of rare earth ions used as the activator include divalent Eu and trivalent Ce in order to obtain blue light emission with good color purity. In addition, trivalent Eu and trivalent Sm are used to obtain red light emission, and trivalent Tb is used to obtain green light emission. Bivalent Sm is also used as an activator.

  The thickness of the phosphor sheet is preferably 5 μm or more in order to hold the phosphor sheet as an integral film, and preferably 100 μm or less in order to achieve appropriate flexibility.

  Examples according to the present invention will be described below, but the present invention is not limited to the following examples.

(Example 1)
In this example, the phosphor sheet of the present invention using phlogopite as the layered silicate crystal and Eu ²⁺ as the rare earth ion of the activator is shown.

First, 2.40 g of K ₂ CO ₃ , 6.65 g of MgF _2, and composition K _0.98 Mg ₃ Si ₃ AlO ₁₀ F ₂ Eu _0.01 in which Eu ²⁺ is activated in phlogopite. Each raw material was mixed with 6.61 g of SiO ₂ , 1.82 g of Al ₂ O ₃ and 0.063 g of Eu ₂ O ₃ . Next, the mixed raw materials were heat-treated at about 1200 ° C. in a nitrogen atmosphere containing 5% hydrogen using a vacuum annealing apparatus, and a phlogopite crystal phosphor activated by divalent Eu was obtained. . When the annealed phosphor was irradiated with 254 nm ultraviolet light with a mercury lamp, blue light emission with good color purity was observed. Further, the obtained phlogopite crystal phosphor showed a diffraction pattern peculiar to phlogopite by X-ray diffraction measurement. The obtained phosphor was pulverized with a planetary ball mill at 300 rpm for 5 minutes to obtain layered silicate crystal pieces. According to observation with a scanning electron microscope, the crushed crystal piece was a crystal piece having a thickness of about 10 nm and a size of about 10 μm × 10 μm. 2 g of this layered silicate crystal piece was weighed and added to 100 cm ³ of distilled water and stirred vigorously to obtain a uniform layered silicate crystal piece dispersion. The dispersion is poured into a 10 cm × 10 cm container with a flat bottom and allowed to stand horizontally, and the layered silicate crystal pieces are slowly deposited and densely laminated, and dried in a drier set at 60 ° C. for 5 hours. Thus, a translucent layered silicate crystal piece sheet having a thickness of about 100 μm was obtained. When the phosphor sheet obtained by the above production method was irradiated with ultraviolet rays of 254 nm of a mercury lamp, blue light emission having a peak near 400 nm was observed. Even after the phosphor sheet was heated to 600 ° C. and returned to room temperature, the structure did not change and the flexibility remained, and the blue light emission with good emission characteristics was maintained.

(Example 2)
In this example, a phosphor sheet that is activated by different rare earth ions and obtains an arbitrary emission color by continuously depositing layered silicate crystals having different emission colors is shown. In particular, examples of phosphor sheets that emit white light are shown.

As the layered silicate crystal blue light, 2.40 g of _K 2 CO ₃ in the same steps as in Example 1, the MgF ₂ 6.65 g, and SiO ₂ 6.61 g, the _Al 2 _{O 3} 1.82g, Eu the ₂ O ₃ were mixed the raw materials as a 0.063 g. Next, the mixed materials were heat-treated at about 1200 ° C. in a nitrogen atmosphere containing 5% hydrogen by using a vacuum annealing apparatus to obtain a phlogopite crystal phosphor activated by divalent Eu. .

As the layered silicate crystal red _light, the K 2 CO ₃ 2.40 g, the MgF ₂ 6.65 g, and SiO ₂ 6.61 g, the _Al 2 _{O 3} 1.82 g, the _Eu 2 _{O 3} as 0.063g Each raw material was mixed. Next, the mixed raw materials were heat-treated at about 1200 ° C. in an air atmosphere to obtain a phlogopite crystal phosphor activated by trivalent Eu.

As a green luminescent layered silicate crystal, K ₂ O ₃ is 2.40 g, MgF ₂ is 6.65 g, SiO ₂ is 6.61 g, Al ₂ O ₃ is 1.82 g, and Tb ₄ O ₇ is 0.030 g. Each raw material was mixed. Next, the mixed raw materials were heat-treated at about 1200 ° C. to obtain a phlogopite crystal phosphor activated by trivalent Tb.

Each phosphor showing blue, red and green light emission obtained by the above process was separately pulverized with a planetary ball mill at 300 rpm for 5 minutes to obtain layered silicate crystal pieces of each color. The obtained blue light emitting layered silicate crystal piece 0.8 g, red light emitting layered silicate crystal piece 0.6 g, and green light emitting layered silicate crystal piece 0.6 g were weighed and added to 100 cm ³ distilled water and stirred vigorously. Thus, a uniform layered silicate crystal piece dispersion was obtained. The dispersion is poured into a 10 cm × 10 cm container having a flat bottom surface and allowed to stand horizontally, the layered silicate crystal pieces are deposited and densely laminated, and dried in a drier set at 60 ° C. for 5 hours. A semi-transparent layered silicate crystal piece sheet having a thickness of about 100 μm was obtained. When the phosphor sheet obtained by the above production method was irradiated with ultraviolet rays of 254 nm of a mercury lamp, white light emission was observed. Even when the phosphor sheet was heated to 600 ° C. and then returned to room temperature, the structure remained unchanged and the light emission characteristics were good.

(Example 3)
In this example, a light-emitting element using the phosphor sheet of the present invention is shown.

  FIG. 1 is a schematic view of a light-emitting element created in this embodiment. A preparation process is the order of the layered silicate sheet | seat used as a board | substrate, an electrode, a dielectric material layer, a fluorescent layer, a dielectric material layer, and a transparent conductive film, and shows a detail below.

Each raw material was mixed with 2.45 g of K ₂ CO ₃ , 6.65 g of MgF ₂ , 6.61 g of SiO ₂ , and 1.82 g of Al ₂ O ₃ . Next, the phlogopite crystal obtained by heat-treating the mixed raw material at about 1000 ° C. was pulverized with a planetary ball mill at 300 rpm for 5 minutes to obtain crystal pieces. 8 g of this layered silicate crystal piece was weighed and added to 300 cm ³ of distilled water and stirred vigorously to obtain a uniform layered silicate crystal piece dispersion. The dispersion is poured into a 10 cm × 10 cm container having a flat bottom surface and allowed to stand horizontally, the layered silicate crystal pieces are deposited and densely laminated, and dried in a drier set at 60 ° C. for 5 hours. The layered silicate sheet 11 and the layered silicate sheet 17 having a thickness of about 400 μm were prepared. On the obtained layered silicate sheet 11, ITO was formed as the transparent conductive film 12 and SiO ₂ was formed as the dielectric layer 13 in this order. 5 μm of a layered silicate phosphor layer 14 containing Eu ²⁺ prepared in the same process as in Example 1 as an activator is deposited, and Si ₃ N ₄ is laminated as the dielectric layer 15 and Al is laminated in the order described. did. Finally, the sheet was sandwiched between the layered silicate sheets 11 and 17, and heat and roll pressure were applied to seal the protruding portion of the sheet. Thereby, the transparent conductive film 12, the dielectric layer 13, the layered silicate phosphor layer 14, the dielectric layer 15, and the electrode film 16 were sealed. When an alternating voltage of 1 kHz was gradually applied to the transparent conductive film 12 and the electrode film 16, blue light emission was observed from about 100V.

It is a schematic diagram of the inorganic EL thin film light emitting element of the present invention.

Explanation of symbols

11 Layered silicate sheet 12 Transparent conductive film 13 Dielectric layer 14 Layered silicate fluorescent layer 15 Dielectric layer 16 Electrode film 17 Layered silicate sheet

Claims (6)

  A phosphor sheet comprising a structure in which layered silicate crystal pieces activated by rare earth ions are laminated.   The phosphor sheet according to claim 1, wherein the layered silicate crystal pieces are laminated with the same plane orientation.   3. The phosphor sheet according to claim 1, wherein a crystal structure of the layered silicate crystal piece is any one of a mica structure, a chlorite structure, a kaolinite structure, and a smectite structure.   The rare earth ion is one or more rare earth ions selected from the group consisting of divalent Eu, divalent Sm, trivalent Ce, trivalent Eu, trivalent Sm, and trivalent Tb. The phosphor sheet according to any one of claims 1 to 3, wherein:   5. The phosphor sheet according to claim 1, wherein a thickness of the phosphor sheet is 5 μm or more and 100 μm or less. 6. A light emitting device using the phosphor sheet according to claim 1.