JP2008274020A - Oxide light emission body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxide light emission body performing light emission with high level at a UV ray area of 200-300 nm by exciting it by an electron ray or a UV ray. <P>SOLUTION: The light emission body comprises an oxide of an element in Group 2A of the Periodic table including a different kind of metal element or a semimetal element and has a light emission peak at a UV ray area of 200-300 nm based on excitation by an electron ray or a UV ray. Preferably, a ratio of the different kind of metal element or the semimetal element relative to the element in Group 2A of the Periodic table is 0.0001-1 mol%, the element in Group 2A of the Periodic table is Mg, and the different kind of metal element is Al. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an oxide light emitter having an emission peak in an ultraviolet region of 200 to 300 nm based on excitation by an electron beam or ultraviolet rays.

  Currently, the phosphor used as a light emitting material in a plasma display panel (PDP) emits light by being excited by vacuum ultraviolet light having a wavelength of 147 nm or electron beam emitted by discharge in xenon gas under vacuum. . However, since PDP phosphors in practical use have low emission intensity due to vacuum ultraviolet rays or electron beams having a wavelength of 147 nm, it has been desired to improve the PDP emission efficiency.

  In addition, in the PDP, although ultraviolet rays and electron beams emitted from the discharge gas existing in the light emitting cell space are emitted in all directions, they are emitted toward the constituent materials surrounding the discharge space other than the phosphor. Most of the emitted ultraviolet rays and electron beams are not used for excitation of the phosphor, and are lost.

  As a technique for effectively utilizing such radiated ultraviolet rays and electron beams and improving the light emission efficiency of the PDP, in Patent Document 1, a thin film magnesium oxide layer conventionally provided as a protective layer on a dielectric layer is disclosed. Furthermore, a method of providing a crystalline magnesium oxide layer containing particulate magnesium oxide crystals is disclosed. The magnesium oxide crystal emits cathode luminescence having a peak in a wavelength range of 200 to 300 nm by electron beam excitation. Specifically, the magnesium vapor is vapor-phase oxidized with magnesium vapor generated by heating magnesium. It is described that a magnesium oxide single crystal having an average particle diameter of 2000 to 4000 mm (0.2 to 0.4 μm) is used.

  As a result, not only the improvement of the luminous efficiency of the PDP but also the improvement of the discharge characteristics such as the discharge delay can be achieved. However, the vapor phase magnesium oxide single crystal disclosed in Patent Document 1 is The emission intensity in the wavelength range of 200 to 300 nm does not reach a sufficient level, and improvement is expected.

On the other hand, Patent Document 2 describes that when a protective film made of magnesium oxide containing a small amount of gadolinium is irradiated with ultraviolet light having a wavelength of 200 nm or less, ultraviolet light having a peak at a wavelength of 315 nm is emitted. An oxide luminescent material having a light emission peak at a wavelength of 200 to 300 nm by containing a metal element or a metalloid element has not been known so far.
Japanese Patent No. 3842276 JP 2001-234164 A

  An object of the present invention is to provide an oxide light emitter that emits light at a high level in an ultraviolet region of 200 to 300 nm by being excited by an electron beam or ultraviolet light in view of the above situation.

  As a result of repeating various studies to solve the above problems, the present inventors include a dissimilar metal element or a semimetal element such as aluminum with respect to the oxide of the Group 2A element of the periodic table such as magnesium. The inventors have found that high-level light emission is performed in an ultraviolet region of 200 to 300 nm based on excitation by an electron beam or ultraviolet rays, and the present invention has been achieved.

  That is, the present invention is a light emitter having a light emission peak in the ultraviolet region of 200 to 300 nm based on excitation by an electron beam or ultraviolet light, and is composed of an oxide of a Group 2A element of the periodic table containing a dissimilar metal element or a metalloid element. The present invention relates to a light emitter.

  Preferably, in the oxide, a ratio of the dissimilar metal element or metalloid element to the Group 2A element of the periodic table is 0.0001 to 1 mol%.

  Preferably, the Group 2A element of the periodic table is Mg, Ca, Sr or Ba. More preferably, the Group 2A element of the periodic table is Mg.

  Preferably, the different metal element or metalloid element is Li, B, Na, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Rb. Y, Nb, Mo, Tc, Ru, Rh, Ag, In, Sb, Cs, La, Pr, Pm, Eu, Gd, Tb, Ho, Tm, Lu, Ta, Re, Ir, Au, Tl, Bi And at least one selected from the group consisting of At. More preferably, the dissimilar metal element is Al.

  Preferably, the oxide has a purity of 99.9% by mass or more when an impurity other than the foreign metal element and the metalloid element is used as an impurity.

Preferably, the oxide is in the form of particles, and the shape observed with a scanning electron microscope is a powder made of cubic primary particles. More preferably, the oxide powder has a cumulative 50% particle diameter (D ₅₀ ) of 0.1 μm or more by laser diffraction scattering particle size distribution measurement. More preferably, the oxide powder has a crystallite diameter of 500 mm or more.

  Preferably, the oxide is produced by a liquid phase method.

  The present invention also relates to an optical device on which the light emitter is mounted.

  According to the present invention, it is possible to provide an oxide light emitter that emits a very high level of light in the ultraviolet region of 200 to 300 nm based on excitation by an electron beam or ultraviolet rays.

  The light emitter of the present invention emits light having a peak at a wavelength of 200 to 300 nm (particularly 230 to 260 nm, particularly 240 to 245 nm) in the ultraviolet region by being excited by an electron beam or ultraviolet rays.

  The light emitter of the present invention is composed of an oxide of a Group 2A element of the periodic table, and the oxide contains a trace amount of a different metal element or a metalloid element. In the present invention, an oxide means a so-called simple oxide, and main elements of the oxide are a group 2A element of the periodic table and an oxygen atom.

  Examples of the Group 2A element of the periodic table include Mg, Ca, Sr, and Ba, and Mg is particularly preferable. That is, the oxide of the Group 2A element of the periodic table in the present invention is most preferably magnesium oxide.

  The dissimilar metal element or metalloid element is not particularly limited as long as it is a metal element or metalloid element different from the Group 2A element of the periodic table used as the main metal of the oxide. Specifically, Li, B , Na, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Rb, Y, Nb, Mo, Tc, Ru, Rh, Ag, In , Sb, Cs, La, Pr, Pm, Eu, Gd, Tb, Ho, Tm, Lu, Ta, Re, Ir, Au, Tl, Bi, At and the like. Only one type of different metal element or metalloid element may be used, or two or more types may be used in combination. Of these, Al is preferable.

  The phosphor of the present invention has a high-level emission peak at a wavelength of 200 to 300 nm because the crystallinity of the oxide changes due to the inclusion of the dissimilar metal element or metalloid element in the crystal structure of the oxide. It is estimated that. It is considered that the intensity of the emission peak is greatly influenced by the electron arrangement in the ground state of the dissimilar metal element or metalloid element contained in the oxide, the ion valence and the ion radius in the ionized state, and the like. Therefore, it is desirable to determine the type of the dissimilar metal element or metalloid element to be doped in consideration of the electron arrangement, ion valence, and ion radius.

In order to further improve the emission intensity, the dissimilar metal element or metalloid element in the oxide is in an ionic state, and a divalent ion of the Group 2A element of the periodic table (that is, Mg ²⁺ , Ca ²⁺ , Sr ²⁺ or Ba ^2+). ) Or ionic radii are significantly different from each other, or the element has an odd number of electrons in the s orbital, p orbital or d orbital in the ground state electron configuration. An element is preferable.

The most preferable ion of the different metal element is Al ³⁺ .

  The content of the dissimilar metal element or metalloid element in the oxide is not particularly limited as long as it is a trace amount relative to the Group 2A element of the periodic table. Specifically, the metal is different from the Group 2A element of the periodic table. As a ratio of an element or a metalloid element, it is the range of 0.0001-1 mol%, and the range of 0.001-1 mol% is preferable. Most preferably, it is about 0.01 mol%. The content can be determined by ordinary elemental analysis.

  In order for the oxide light emitter of the present invention to emit light having a peak at a wavelength of 200 to 300 nm (especially 230 to 260 nm, particularly 240 to 245 nm) when excited by an electron beam or ultraviolet light, The oxide is preferably in powder form. Further, it is more preferable that the oxide has a cubic primary particle shape. This shape can be confirmed by a scanning electron microscope. Note that the “cubic shape” does not indicate a strict cube in a geometric sense, but indicates a shape that can be recognized as a cube by visually observing a micrograph as shown in FIG. In addition, the oxide preferably has a property in which cubic primary particles are separated without agglomeration and have good dispersibility.

Further, the oxide particles preferably have a large average particle diameter. Specifically, the cumulative 50% particle diameter (D ₅₀ ) measured by laser diffraction scattering type particle size distribution satisfies 0.1 μm or more. Those are preferred. The D ₅₀ is preferably 0.3 μm or more, and more preferably 0.5 μm or more. Note that D ₅₀ is a median diameter, which is a particle diameter (μm) corresponding to 50% by volume in a cumulative particle size graph. When a powder is divided into two by a certain particle diameter, it is smaller on the larger side. It is the particle size where the sides are equal.

  Further, the crystallite diameter measured using the X-ray diffraction method is preferably 500 mm or more, and more preferably 1000 mm or more.

The primary particles of the oxide are generally large and do not contain fine powder. Specifically, the oxide powder has a specific surface area measured by the BET method of 5.0 m ² / g or less. preferable. More preferably, it is 4.0 m < ² > / g or less, More preferably, it is 2.5 m < ² > / g or less, Most preferably, it is 1.0 m < ² > / g or less.

The oxide light-emitting body of the present invention is preferably in the form of particles, the primary particles are arranged in a cubic shape, fine particles are not attached to the surface of the cubic crystal, and the surface is clean. And smooth. For this reason, it is preferable that the oxide has a uniform particle size, that is, a narrow particle size distribution. Specifically, a cumulative 10% particle diameter (D ₁₀ ) and a cumulative 90% by laser diffraction scattering particle size distribution measurement. It is preferable that the ratio D ₉₀ / D ₁₀ of% particle diameter (D ₉₀ ) satisfies 10.0 or less. More preferably, it is 6.0 or less, More preferably, it is 4.5 or less.

  Although the oxide light emitter of the present invention contains a different metal element or a metalloid element, the purity when the contained element other than the different metal element and the metalloid element is an impurity as the oxide of the Group 2A element of the periodic table is high. Purity. Specifically, 99.9 mass% or more is preferable. This numerical value of purity is obtained by using an element other than the dissimilar metal element and metalloid element contained in the oxide light emitter as an impurity in order to perform high-level light emission in the ultraviolet region of 200 to 300 nm, and the content of the impurity. It is a numerical value considering only.

  Next, a method for producing the oxide light emitter of the present invention will be described.

  In general, as a method of producing an oxide of a Group 2A element of the periodic table, a precursor such as a hydroxide or a carbonate obtained by a vapor phase method by oxidizing a vapor of a metal element of the element and an aqueous solution reaction. Although the liquid phase method by firing is known, as a method for producing the oxide light-emitting body of the present invention, the doping of different elements and the content thereof can be precisely controlled. The method is preferably used.

  As a specific manufacturing method, various methods known as oxide manufacturing methods can be applied, and the oxide phosphor of the present invention may be obtained by mixing different elements in the process. However, the liquid phase method in the case where the oxide of the Group 2A element of the periodic table is magnesium oxide will be described in detail below.

  The magnesium oxide precursor used in the liquid phase method may be a conventionally used precursor and is not particularly limited. Examples thereof include magnesium hydroxide, basic magnesium carbonate, magnesium carbonate, and magnesium oxalate. Especially, since the characteristic of the oxide light-emitting body obtained is excellent, magnesium hydroxide, basic magnesium carbonate, and a mixture thereof are preferable.

  In order to produce the oxide light-emitting body of the present invention, it is preferable to prepare the magnesium oxide precursor so that it contains a trace amount of different metal elements or metalloid elements. However, when the precursor contains a large amount of impurities, the purity of the obtained oxide light-emitting body is lowered, so that it is preferable that the impurities other than the different metal element or metalloid element are less.

  By firing the magnesium oxide precursor in the presence of halide ions, the resulting oxide light-emitting body can be made cubic and the purity and crystallinity can be improved. Examples of halide ions include chloride ions, fluoride ions, bromide ions, and iodide ions, with chloride ions being preferred. Specific examples of the compound containing halide ions include hydrochloric acid, ammonium chloride, sodium chloride, potassium chloride, magnesium chloride and the like.

  The abundance of halide ions is preferably in the range of 0.5 to 30% by mass with respect to the total amount of the magnesium oxide precursor. If the amount of halide ions is too small, the crystals are difficult to grow in a cubic shape. Conversely, if the amount is too large, the crystals of the oxide light emitter are difficult to grow. Preferably it is the range of 1.0-25 mass%, More preferably, it is the range of 10-25 mass%.

  The compound containing halide ions may be the magnesium oxide precursor itself, may be derived from impurities contained in the magnesium oxide precursor, or the magnesium oxide precursor is obtained by a solution synthesis method. It may be a by-product generated during the preparation, or may be added separately to the magnesium oxide precursor, or in a gas atmosphere in a closed or open furnace, for example, gaseous hydrogen chloride Alternatively, it may be added as molecular chlorine or the like. Further, impurities contained in the magnesium oxide precursor and by-products generated during the preparation of magnesium oxide may be sufficiently removed by washing or the like, and may be newly added to the magnesium oxide precursor or in a gas atmosphere.

  In the case where the magnesium oxide precursor is a mixture of basic magnesium carbonate and magnesium hydroxide, the precursor can be prepared by a solution synthesis method. For example, (1) an aqueous magnesium chloride solution and an aqueous sodium hydroxide solution, and a trace amount A magnesium hydroxide slurry containing a trace amount of different metal element or metalloid element ions is obtained by mixing aqueous solutions of different metal elements or metalloid chlorides or oxides, and (2) hydroxylation in the slurry. A part of magnesium is carbonated to obtain a slurry containing basic magnesium carbonate, magnesium hydroxide and different metal or metalloid element ions. (3) The slurry is filtered to obtain basic magnesium carbonate and magnesium hydroxide. To obtain a mixture of This mixture contains a trace amount of different metal element or metalloid element ions, and also contains chloride ions as magnesium chloride as a starting material or sodium chloride as a by-product.

  Specifically, in the step (1), a solution obtained by adding a chloride or oxide of a dissimilar metal element or metalloid element to a considerable amount of an aqueous sodium hydroxide solution and dissolving it, an aqueous magnesium chloride solution and an aqueous hydroxide. When precipitation occurs in this method, the chloride or oxide of a dissimilar metal element or metalloid element may be added to the magnesium chloride aqueous solution. You may carry out by adding and making it dissolve in the sodium hydroxide aqueous solution.

  After obtaining the magnesium hydroxide slurry in the step (1), by diluting with water, the concentration of the slurry is preferably in the range of 50 to 100 g / L, more preferably in the range of 60 to 90 g / L. Adjust it. This is because the viscosity of the slurry is reduced by lowering the concentration of the slurry so that the carbonation reaction in the next step (2) proceeds uniformly.

  In the step (2), a part of magnesium hydroxide in the slurry is carbonated by blowing carbon dioxide into the slurry. The temperature of the carbonization reaction is preferably 40 to 80 ° C. In this temperature range, conversion from magnesium hydroxide to basic magnesium carbonate is carried out quickly, and the reaction efficiency is good. Furthermore, within this temperature range, a mixture of basic magnesium carbonate and magnesium hydroxide having a particle size excellent in filtration efficiency can be obtained.

  The amount of carbon dioxide used in the carbonation reaction is such that a part of the magnesium hydroxide in the magnesium hydroxide slurry is converted to basic magnesium carbonate to give a mixture of basic magnesium carbonate and magnesium hydroxide. The amount that can be. It is preferable that the specific usage-amount of a carbon dioxide gas is 0.2-2.0 molar equivalent with respect to 1 mol of magnesium hydroxide. Within this range, it is possible to efficiently obtain a mixture of basic magnesium carbonate and magnesium hydroxide having excellent filtration efficiency.

  In the step (3), the slurry containing the basic magnesium carbonate and magnesium hydroxide obtained in the step (2) is filtered to obtain a mixture of the basic magnesium carbonate and magnesium hydroxide as a solid. Since this solid mixture contains chloride ions, it may be dried as it is without being washed, and then subjected to calcination described later, or this mixture may be used with an appropriate amount of water. The amount of chloride ions in the cake may be reduced to an appropriate level by washing, and then subjected to drying and baking. If the washing is sufficiently performed, the chloride ion content becomes too low, and the degree of washing may be controlled by the amount of washing water used, the washing time, and the like. However, a halide ion-containing compound may be added separately after sufficient washing to completely remove chloride ions.

  In the case where the magnesium oxide precursor is magnesium hydroxide, the precursor can be prepared by a solution synthesis method, for example, (4) Magnesium chloride aqueous solution and sodium hydroxide aqueous solution, and a trace amount of different metal elements or metalloid elements An aqueous solution of chloride, oxide, or the like is mixed to obtain a magnesium hydroxide slurry containing a trace amount of different metal element or metalloid element ions. (5) The slurry is filtered to obtain solid magnesium hydroxide. . This solid substance contains a trace amount of different metal element ions, and also contains chloride ions as magnesium chloride as a starting material or sodium chloride as a by-product.

  The step (4) is the same as the step (1) described above.

  In the step (2), the magnesium hydroxide slurry obtained in the step (1) is filtered to obtain solid magnesium hydroxide. Since this solid contains chloride ions, it may be treated as described above.

  In producing the oxide light-emitting body of the present invention, the magnesium oxide precursor can be calcined in the presence of halide ions in either a closed system or an open system, but it is more preferable to perform in a closed system. . Here, the closed system refers to a system that is almost sealed so that the gas existing in the space for firing does not substantially flow out to the outside and does not substantially flow in from the outside. This is different from a normal firing method that is performed in an atmosphere of oxygen, oxygen, or the like, or while flowing an air flow thereof. By firing in a closed system, halide ions do not scatter to the outside, but remain in the firing container and sufficiently intervene in the process of growth of oxide powder crystals, resulting in a highly crystalline cube It becomes possible to obtain a crystal powder.

  Firing in this closed system can be performed, for example, by using a sealed electric furnace that does not substantially flow in or out of the atmospheric gas, or by placing it in a crucible that can be sealed. The temperature during firing is preferably about 600 ° C to 1400 ° C, and most preferably about 1200 ° C. When the temperature at the time of baking is too high, the crystal | crystallization obtained may aggregate and a dispersibility may worsen. Although it depends on the temperature, the firing time is usually about 1 to 10 hours. For example, when the temperature is about 1200 ° C., about 5 hours is appropriate. In addition, although it does not specifically limit as a speed | rate at the time of heating up for baking, About 5-10 degreeC / min is good.

  Cubic oxide powder with good crystallinity grows by firing under the above-mentioned conditions, but in order to perform firing under hermetic conditions, impurities such as halide ion-containing compounds are not sufficiently removed, It is mixed in the powder after firing. In order to reduce the mixing amount of the halide ion-containing compound and increase the purity of the oxide powder, it is preferable to perform the second firing in the open system after the primary firing in the closed system.

  This secondary firing may be a firing performed in a normal open system. For example, air or an oxygen atmosphere is preferable so that impurities contained in the precursor can be removed as an oxidizing gas. Can be carried out in a gas furnace having atmospheric gas flow, an electric furnace under an oxygen stream, or the like. The temperature, time, and gas in the furnace during secondary firing are not particularly limited as long as impurities such as halide ion-containing compounds can be removed, but crystal growth has already been completed by primary firing. The secondary firing time may be relatively short.

  Since the oxide light emitter of the present invention emits light strongly at a wavelength of 200 to 300 nm in the ultraviolet region, it can be applied to various optical devices including a plasma display panel.

  In particular, the oxide light emitter of the present invention can be used as a magnesium oxide crystal constituting a crystalline magnesium oxide layer (crystal emissive layer) provided on a protective film in a PDP. In order to form the crystalline magnesium oxide layer, the oxide phosphor of the present invention may be directly attached to the protective film by a spray method, an electrostatic coating method, or the like, or a paste containing the phosphor The paste may be applied to the protective film and dried.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

In the following examples, various physical properties and the like were measured according to the following procedure.
(1) Cathode luminescence measurement method A device (cathode luminescence measurement device, manufactured by HORIBA) that combines a scanning electron microscope with a photodetector and a spectroscope is used, and an electron from the electron gun of the scanning electron microscope is used as a sample. The emission spectrum of luminescence emitted from the sample was measured by irradiating the line.
(2) Scanning Electron Microscope (SEM) Observation Method Using a scanning electron microscope (trade name: JSM-5410, manufactured by JEOL), an SEM composition image was photographed, the particle shape was observed, and one side of the cubic magnesium oxide was observed. The length was measured.
(3) Method for Measuring Impurity Amount of Magnesium Oxide Impurity amount of oxide was measured after the sample was dissolved in acid using an ICP emission analyzer (trade name: SPS-1700, manufactured by Seiko Instruments Inc.).
(4) Oxide purity measurement method The purity of the oxide is determined by the amount of impurities measured except for the added foreign metal element and metalloid element (aluminum in Example 1, yttrium in Example 2, and vanadium in Example 3). Was calculated as a value subtracted from 100% by mass.
(5) Method for measuring crystallite diameter The crystallite diameter of the phosphor of the present invention was measured using a powder X-ray diffraction method and calculated by the Scherrer equation.
Example 1
A magnesium hydroxide (Mg (OH) ₂ ) slurry was obtained by reacting a magnesium chloride (MgCl ₂ ) aqueous solution with a sodium hydroxide (NaOH) aqueous solution. In this reaction, an appropriate amount of aluminum chloride (AlCl ₃ ) hexahydrate (manufactured by Kanto Chemical Co., Ltd.) is added to the final product magnesium oxide powder so that about 0.01 mol% of aluminum is contained with respect to magnesium. What was dissolved in an aqueous solution of sodium oxide (NaOH) was added.

This magnesium hydroxide slurry was diluted with ion-exchanged water to a slurry concentration of 75 g / L, and while stirring the diluted magnesium hydroxide slurry 30 L at a speed of 100 to 150 rpm, steam was blown in to adjust the liquid temperature to 60 ° C. . Next, while maintaining the liquid temperature at 60 ° C., 3/4 equivalent of carbon dioxide gas having a CO ₂ concentration of 100% by volume was blown from the bottom of the tank, and a part thereof was converted into basic magnesium carbonate.

  Subsequently, this slurry was filtered, and the obtained cake was washed with ion-exchanged water. Thereafter, the cake was dried with a dryer at 120 ° C. for 10 hours to obtain a precursor.

  Next, the precursor, which is a mixture of magnesium hydroxide and basic magnesium carbonate, is heated to 1200 ° C. at a temperature rising rate of 6 ° C./min in a closed electric furnace that does not flow in and out of atmospheric gas in the air atmosphere. Then, it was fired by holding at the same temperature for 5 hours to form a magnesium oxide powder. This was further refired at 1200 ° C. for 1 hour in a gas furnace with an inflow of atmospheric gas in an air atmosphere to obtain a magnesium oxide powder.

  FIG. 1 shows the results of measuring the cathode luminescence of the obtained magnesium oxide powder. 1 that the magnesium oxide powder obtained in Example 1 has an emission peak with a very high emission intensity at a wavelength of 200 to 300 nm (particularly 230 to 260 nm, especially 240 to 245 nm).

Moreover, the result of having observed the obtained magnesium oxide powder with the scanning electron microscope (15,000 times) is shown in FIG. The observed crystals were almost cubic in shape, and had extremely uniform particle shapes, and the crystallite diameter was 1000 mm or more. Further, it can be seen that one side of the cubic crystal is about 0.1 to 1 μm before and has a very narrow particle size distribution. Unlike FIG. 3 described later, fine particles are not attached to the crystal surface, and the crystal surface is smooth and clean. Furthermore, individual cubic crystal grains are well separated.
Example 2
An appropriate amount of yttrium chloride (YCl ₃ ) hexahydrate instead of aluminum chloride (AlCl ₃ ) hexahydrate so that the final product magnesium oxide powder contains about 0.01 mol% of yttrium with respect to magnesium. A magnesium oxide phosphor was synthesized in the same manner as in Example 1 except that (manufactured by Kanto Chemical Co., Inc.) was used.

The crystallite diameter of the obtained magnesium oxide powder was 1000 mm or more. Moreover, the result of having measured cathode luminescence is shown in FIG.
Example 3
Instead of aluminum chloride (AlCl ₃ ) hexahydrate, an appropriate amount of vanadium oxide (V ₂ O ₅ ) (so that the final product magnesium oxide powder contains about 0.01 mol% of vanadium with respect to magnesium ( A magnesium oxide phosphor was synthesized in the same manner as in Example 1 except that a solution prepared by dissolving in Kanto Chemical Co., Ltd. with hydrochloric acid and then dissolving in a magnesium chloride (MgCl ₂ ) aqueous solution was added.

The crystallite diameter of the obtained magnesium oxide powder was 1000 mm or more. Moreover, the result of having measured cathode luminescence is shown in FIG.
Comparative Example 1
Magnesium oxide powder was obtained in the same manner as in Example 1, except that aluminum chloride hexahydrate dissolved in an aqueous sodium hydroxide solution was not added during the production of the magnesium hydroxide slurry.

FIG. 1 shows the results of measuring the cathode luminescence of the obtained magnesium oxide powder. From FIG. 1, it is clear that the magnesium oxide powder obtained without doping the different elements in Comparative Example 1 has a slight emission peak at a wavelength of 200 to 300 nm, but the emission intensity is not as high as in Example 1. It is.
Comparative Example 2
FIG. 1 shows the results of measuring the cathode luminescence of magnesium oxide powder produced by a commercially available gas phase method. From FIG. 1, it is clear that the magnesium oxide powder obtained by the vapor phase method has a slight emission peak at a wavelength of 200 to 300 nm, but the emission intensity is not as high as that of Example 1.

  Moreover, the result of having observed the magnesium oxide powder by the said vapor phase method with the scanning electron microscope (15,000 times) is shown in FIG. Although cubic crystals are included, at the same time, it can be seen that a large amount of fine, fine-grained crystals are attached, and the surface cannot be said to be clean.

  Further, Table 1 shows the results of measuring the oxide purity of Examples 1 to 3 and Comparative Examples 1 and 2, and the ratio (mol%) of the additive element to magnesium in the oxides of Examples 1 to 3.

  Since the oxide light emitter of the present invention has a high emission peak in the ultraviolet region of 200 to 300 nm based on excitation by an electron beam or ultraviolet rays, it can be widely applied to optical devices using this emission wavelength region. Is possible. In particular, by using as a magnesium oxide crystal constituting a crystalline magnesium oxide layer provided on a protective film in a PDP, the luminous efficiency and discharge delay of the PDP can be improved.

The graph which shows the emission spectrum of the cathode luminescence measured by the Example and each comparative example Electron micrograph of the magnesium oxide powder obtained in Example 1 Electron micrograph of the magnesium oxide powder of Comparative Example 2

Claims (12)

A light emitter having an emission peak in the ultraviolet region of 200 to 300 nm based on excitation by an electron beam or ultraviolet rays,
A light emitter comprising an oxide of a Group 2A element of the periodic table containing a different metal element or a metalloid element.   The light-emitting body according to claim 1, wherein in the oxide, a ratio of the different metal element or metalloid element to the Group 2A element of the periodic table is 0.0001 to 1 mol%.   The light emitter according to claim 1 or 2, wherein the Group 2A element of the periodic table is Mg, Ca, Sr, or Ba.   The light emitter according to claim 1 or 2, wherein the Group 2A element of the periodic table is Mg.   The different metal element or metalloid element is Li, B, Na, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Rb, Y, From Nb, Mo, Tc, Ru, Rh, Ag, In, Sb, Cs, La, Pr, Pm, Eu, Gd, Tb, Ho, Tm, Lu, Ta, Re, Ir, Au, Tl, Bi and At The light-emitting body according to claim 1, which is at least one selected from the group consisting of:   The light-emitting body according to claim 1, wherein the different metal element is Al.   The phosphor according to any one of claims 1 to 6, wherein the oxide has a purity of 99.9% by mass or more when an element other than the different metal element and the metalloid element is used as an impurity.   The light-emitting body according to claim 1, wherein the oxide is in the form of particles, and the shape observed with a scanning electron microscope is a powder composed of cubic primary particles. The luminous body according to claim 1, wherein the oxide powder has a cumulative 50% particle diameter (D ₅₀ ) of 0.1 μm or more by laser diffraction / scattering particle size distribution measurement.   The light emitter according to any one of claims 1 to 9, wherein a crystallite diameter of the oxide powder is 500 mm or more.   The light emitter according to any one of claims 1 to 10, wherein the oxide is produced by a liquid phase method.   An optical device comprising the light emitter according to any one of claims 1 to 11.