JP5120949B2 - Method for producing white phosphor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new laminate type white fluorescent material which shows a white fluorescence excellent in the color rendering property resulting from that a fluorescent light spectrum is spread broadly to the range of 390-800 nm with the excitation by the ultraviolet light, the near ultraviolet light or the like and besides in which, for example, a warm-colored white or a cold-colored white can be freely adjusted, and to provide an industrially advantageous manufacturing method thereof. <P>SOLUTION: The laminate type white fluorescent material is a material in which a substrate is provided thereon sequentially with an oxide white fluorescent material crystal thin layer, an amorphous alumina thin layer and an oxide red fluorescent material crystal thin layer or an oxide blue fluorescent material crystal thin layer. The above laminate type white fluorescent material is such that the oxide white fluorescent material is a vanadium oxide-based compound. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a novel laminated white phosphor useful as a white LED, an indoor lighting fixture, a lighting device that emits white light, and an efficient manufacturing method thereof.

  In recent years, many phosphor materials are used not only for flat panel displays such as PDP and FED, but also for lighting devices such as white LEDs and fluorescent lamps for indoor lighting, and their uses are expanding. In particular, white LEDs and fluorescent lamps for illumination use ultraviolet to blue light as excitation light, and produce white light by combining phosphors having emission intensities at various wavelengths. Specifically, when the excitation light source is blue, yellow, green and red phosphors emit light to obtain white light, and when the excitation light source is ultraviolet light, blue (green), yellow and red phosphors are obtained. To obtain white light. (Patent Document 1)

However, white light obtained by combining a plurality of phosphors also has problems such as color loss and strong light emission only at specific wavelengths, and efforts to improve color rendering are necessary for use as indoor lighting. Become. Therefore, the phosphor used in the white LED for illumination needs to have a wide emission wavelength, and it is desirable to improve the color rendering by reproducing ideal white light with as few phosphors as possible. .
However, it is usually difficult for a single substance to exhibit white fluorescence with as good a color rendering property as possible.
In order to solve such a problem, the present inventors first made a vanadium oxide (AVO ₃ ; A is one or more selected from the group consisting of K, Rb, and Cs) as a single substance. It has been reported that it has a broad emission spectrum and emits white fluorescence having a fluorescence spectrum having a maximum in the vicinity of 515 to 540 nm and broadening in the range of 390 to 800 nm by excitation with ultraviolet and near ultraviolet light at 250 to 390 nm ( Patent Document 2).

  Since the fluorescence spectrum emitted from this vanadium oxide phosphor is an emission spectrum close to the spectrum of lighting fixtures currently used in consumer and ordinary fluorescent lamps, it can be used as it is as a phosphor for white LEDs. it can. In addition, since the peak of the emission spectrum is in the range of 515 to 540 nm, the color temperature is high, but it can also be combined with a phosphor having strong emission on the long wavelength side, and a warmer white color can be obtained. Since it does not contain mercury or lead, it has many advantages such as less adverse effects on the environment and human body.

By the way, generally, in the application of inorganic solids, when applied to a small device or a member having a planar shape, it is desired to make the film thinner than a powder body or a bulk body. Also, in relation to the substrate, it is considered preferable to lower the film forming temperature as much as possible, and in recent years, the demand for it has been increasing abundantly. There is a strong demand for methods.
For example, even when forming a film on a glass substrate, it is necessary to carry out at a low temperature of 600 ° C. or lower, and it is necessary to reduce the film forming process temperature. Here, the reduction of the film formation temperature increases the choices of the substrate, so that the application range is expected to be expanded. For example, if it becomes possible to lower the film forming temperature to about 200 ° C. or less, it becomes possible to form a film on an organic substrate such as plastic, and development of a flexible light-emitting material can also be expected.

Therefore, the present inventor has developed a method capable of forming a film (crystallization) even when the substrate temperature is near room temperature, as a method for manufacturing the vanadium oxide phosphor (AVO ₃ ) proposed in Patent Document 2 above ( Patent Document 3).
In this method, an organic metal solution in which the metal ratio of A and V is mixed at a ratio of substantially 1: 1 is applied onto an organic substrate, and crystallization is performed by irradiating with vacuum ultraviolet rays. This damages the organic substrate. And has many advantages such that it can be crystallized directly on the substrate.

However, the vanadium oxide phosphors (AVO ₃ ) described in Patent Document 1 and Patent Document 2 have a color rendering index of about 70, and are subtle depending on the application, such as various indoor lighting devices. It was extremely difficult to adjust the fluorescent white color.

JP-A-11-31845 Japanese Patent Application No. 2007-224846 Japanese Patent Application No. 2007-259862

  The present invention is excited by ultraviolet / near-ultraviolet light, etc., has a fluorescence spectrum extending in the range of 390 to 800 nm, exhibits white fluorescence with excellent color rendering properties, and can freely adjust, for example, warm-colored or cold-colored white It is an object of the present invention to provide a novel white laminated phosphor that can be manufactured and an industrially advantageous method for producing the same.

According to this application, the following invention is provided.
<1> A laminated white phosphor in which an oxide white phosphor crystal thin film, an amorphous alumina thin film, and an oxide phosphor crystal thin film are sequentially provided on a substrate.
<2> The laminated white phosphor according to <1>, wherein the substrate is an organic substrate.
<3> The laminated white phosphor according to <1>, wherein the oxide white phosphor is a vanadium oxide compound.
<4> The laminated white phosphor according to <1>, wherein the oxide phosphor produced on the top is a red phosphor or a blue phosphor.
<5> The laminated white phosphor according to <1>, wherein the white fluorescent material having a fluorescence spectrum broadening in a range of 390 to 800 nm is emitted by ultraviolet / near ultraviolet light or an ultraviolet / near ultraviolet excitation light emitting element.
<6> After the substrate provided with the first oxide phosphor crystal thin film is kept at a temperature of room temperature to 150 ° C., an organic compound solution containing aluminum is applied to the surface and irradiated with ultraviolet rays having a wavelength of 400 nm or less. The method for producing a laminated white phosphor according to any one of <1> to <5>, wherein an amorphous alumina thin film is formed, and an oxide phosphor crystal thin film is formed thereon.
<7> The method for producing a laminated white phosphor according to <6>, wherein the ultraviolet light source is an ultraviolet laser or an ultraviolet lamp.
<8> The method for producing a laminated white phosphor according to <7>, wherein the ultraviolet laser is irradiated after irradiation with an ultraviolet lamp.
<9> An oxide phosphor crystal is formed by providing a coating film having a metal composition of an oxide phosphor on an amorphous alumina thin film, and irradiating the coating film with an ultraviolet lamp having a wavelength of 400 nm or less and then with an ultraviolet laser. A method for producing a laminated white phosphor according to any one of <6> to <8>, wherein a thin film is formed.
<10> On the amorphous alumina thin film, a film having a metal composition of an oxide phosphor is physically vapor-deposited, and the oxide phosphor is irradiated with an ultraviolet lamp having a wavelength of 400 nm or less and then an ultraviolet laser. A method for producing a laminated white phosphor according to any one of <6> to <8>, wherein a crystalline thin film is formed.
<11> A white LED using the laminated white phosphor according to any one of <1> to <5>.
<12> A display device using the laminated white phosphor according to any one of <1> to <5>.
<13> A lighting fixture using the laminated white phosphor according to any one of <1> to <5>.
<14> A display device using the laminated white phosphor according to any one of <1> to <5>.

The laminated white phosphor of the present invention is excited by ultraviolet / near ultraviolet light or the like, broadens the fluorescence spectrum in the range of 390 to 800 nm, and exhibits white fluorescence excellent in color rendering. Further, a warm white color can be obtained by combining with a red phosphor having a strong light emission on the long wavelength side. Furthermore, a cold white color can be obtained by combination with a blue phosphor having strong light emission on the short wavelength side.
According to the manufacturing method of the present invention, a target laminated white phosphor crystallized thin film can be manufactured even when the substrate temperature is room temperature. In addition, since film formation by light irradiation can be performed at a low temperature of 200 ° C. or lower, it can be directly formed on an organic substrate such as plastic as well as an inorganic solid substrate such as a glass substrate. Therefore, not only can the material cost be reduced, but it can also be applied to flexible light-emitting materials such as displays and lighting fixtures that can be bent freely.
In addition, the CaTiO ₃ : Pr ³⁺ thin film, which is the second oxide phosphor described in one of the examples of the present invention, is a material that normally requires high temperature (800 to 1300 ° C.). The ability to form indicates that the method can be applied to many other substances. As a result, the fluorescent color can be controlled by the combination of the upper and lower phosphors and the film thickness with the protective layer interposed therebetween. In other words, the present invention can be applied to flexible light-emitting materials using organic substrates, such as inexpensive displays that can be bent and lighting fixtures.

The laminated white phosphor of the present invention comprises an oxide white phosphor crystal thin film which is a first phosphor crystal thin film on a substrate, and an amorphous alumina thin film which is a protective layer thereon. A second phosphor crystal thin film, for example, an oxide red phosphor crystal thin film or an oxide blue phosphor crystal thin film is sequentially provided thereon.
Hereinafter, the laminated white phosphor will be described.

  As the substrate, either an inorganic substrate such as glass or alumina, or an organic substrate such as PET or polyimide can be used. In the case of an inorganic substrate, a film can be formed on any substrate as long as it is not melted at room temperature or melted by humidity in the air. In addition, although the organic substrate is crystallized by light irradiation, in actuality, when light irradiation is performed, the substrate temperature is heated to about 60 to 70 ° C. for an irradiation time of about 10 minutes. Therefore, it is desirable to use a material that does not melt near this temperature. In addition, since many organic substrates such as plastic emit strong blue light, it is desirable to select a substrate that emits less blue light to exhibit white light.

As the first phosphor crystal thin film provided on this substrate, a crystal thin film of oxide white phosphor is used.
Any oxide white phosphor may be used as long as it emits white fluorescence that broadens in the range of 390 to 800 nm by an ultraviolet / near ultraviolet light or ultraviolet / near ultraviolet excitation light emitting element.

The oxide white phosphor preferably used in the present invention is a vanadium oxide phosphor represented by AVO ₃ (A is one or more atoms selected from K, Rb and Cs).
This vanadium oxide phosphor thin film has an excitation spectrum in the range of 250 to 390 nm that can be excited by an ultraviolet / near ultraviolet LED that is an excitation light source of a white LED. The fluorescence spectrum emitted by this excitation light spreads from 390 to 800 nm and emits white light. Therefore, it is suitable as a phosphor for white LED. Since the peak of the emission spectrum is in the range of 520 to 540 nm, the color temperature is relatively high, but a warm white color can be obtained by combining with a phosphor having strong emission on the long wavelength side.

In the present invention, a specific protective layer, that is, a protective layer made of an amorphous alumina thin film is used on the first phosphor crystal thin film.
Without the protective layer, ablation occurs at the time of ultraviolet laser irradiation, and the upper oxide phosphor thin film cannot be formed, so that the object of the present invention cannot be achieved. In the case of an amorphous SiO ₂ film or MgO film often used as another protective layer, for example, a surface protective layer of a phosphor thin film material, the excellent film quality as in the present invention cannot be provided.

In the present invention, a second oxide phosphor thin film is provided on the amorphous alumina thin film as the protective layer. There are various reasons for the provision of the second oxide phosphor crystal thin film, but a warm white color is produced by combining white phosphor with good color rendering properties and a red phosphor that emits strong light on the long wavelength side. On the contrary, it is possible to obtain a cold-colored white color by combining with a blue phosphor having a strong light emission on the short wavelength side.
Conventionally known oxide red phosphors and oxide blue phosphors can be used. Examples of the red oxide phosphor include CaTiO ₃ : Pr ³⁺ , Y ₂ O ₃ : Eu ³⁺ , SrTiO ₃ : Pr ³⁺ , Al ³⁺ , (Ca, Sr) TiO ₃ : Pr ³⁺ , YVO ₄ : Eu ^{3+ and the} like. Is done. Examples of the oxide blue phosphor include ZnO and BaMgAl ₁₀ O ₁₇ : Eu ²⁺ .

The laminated white phosphor according to the present invention emits white fluorescence that broadens in a fluorescence spectrum of 390 to 800 nm by ultraviolet / near ultraviolet light or ultraviolet / near ultraviolet excitation light emitting element. It has an excitation spectrum in a range of 250 to 390 nm that can be excited by an ultraviolet / near ultraviolet LED that is an excitation light source of a white LED. The fluorescence spectrum emitted by this excitation light spreads from 390 to 800 nm and emits white light. Therefore, it is suitable as a phosphor for white LED. The peak of the emission spectrum is in the range of 520 to 540 nm and the color temperature is 5000 to 6500 K. A warm white color can also be obtained by combination with a phosphor having strong emission on the long wavelength side. In addition, since it does not contain mercury or lead, there are few negative effects on the environment and human body.
Therefore, the vanadium oxide phosphor thin film is extremely useful as a white LED, and can be used, for example, as a lighting device such as a daily light that requires white light or a display device such as a backlight used in various display devices. Can do. CIE chromaticity coordinates, for example RbVO ₃ at x = 0.316, y = 0.424, CsVO 3 at x = 0.306, a y = 0.418. Both have high internal quantum efficiencies of about 80 to 90%.

Next, a method for producing the laminated white phosphor of the present invention will be described.
In the method for producing the laminated white phosphor according to the present invention, the substrate provided with the first oxide phosphor crystal thin film is kept at a temperature of room temperature to 150 ° C., and then an organic compound solution containing aluminum is applied to the surface. Then, an amorphous alumina thin film is formed by irradiating with an ultraviolet ray having a wavelength of 400 nm or less, and a second oxide phosphor crystal thin film is formed thereon.

In order to provide the first oxide white phosphor crystal thin film represented by the composition formula AVO ₃ on the substrate, for example, A formed on the substrate (A is one selected from K, Rb and Cs or 2 or more atoms) and a thin film containing V (vanadium) in a substantially 1: 1 atomic ratio is maintained at a temperature of 25 ° C. to 450 ° C., and then an ultraviolet laser or an ultraviolet lamp having a wavelength of 400 nm or less is used. Irradiation may be performed to crystallize the vanadium oxide.
Here, A (A is one or more atoms selected from K, Rb and Cs) and a thin film containing V formed on the substrate are a compound containing A (ion) and V. It means a thin film obtained by forming a mixture with a compound containing a compound on a substrate by various methods.
Examples of the compound containing A (ion) include inorganic compounds or organic compounds containing one or more atoms selected from K, Rb, and Cs.
Examples of the inorganic compound include precursors such as amorphous KVO ₃ , RbVO ₃ , and CsVO ₃ that have not been crystallized.
Examples of organic compounds generally include β-diketonates, long-chain alkoxides having 6 or more carbon atoms, and organic acid salts that may contain halogen.
Specific examples include naphthenate, 2-ethylhexanoate, acetylacetonate and the like of these metals.
In addition, the compound containing A (ion) may contain one or more selected from Li, Na, and NH ₄ .

As a compound containing V, the inorganic compound or organic compound containing this is mentioned.
Examples of the inorganic compound include precursors such as amorphous KVO ₃ , RbVO ₃ , and CsVO ₃ that have not been crystallized.
Examples of organic compounds generally include vanadium-containing β-diketonates, long-chain alkoxides having 6 or more carbon atoms, and organic acid salts that may contain halogen.
Specific examples include vanadium diethylhexanoate and acetylacetonate.

The compound containing A and V is mixed so that the atoms of A and V are substantially 1: 1 to obtain a solution for forming a thin film. In this case, a solvent such as toluene / xylene may be used if necessary.
Subsequently, this solution is formed into an organic metal thin film on a substrate by an appropriate method. In this case, in order to produce a high-quality film that easily reacts with an oxide, it is desirable to form a film immediately after preparing the solution (after mixing the organometallic solution containing A and V). The film method is not limited, and sputtering, MBE, vacuum deposition, CVD, chemical solution method (coating pyrolysis method, spray method) and the like are appropriately used.

Next, after the formed thin film is kept at a temperature of 25 ° C. to 450 ° C., it is irradiated with an ultraviolet laser or an ultraviolet lamp having a wavelength of 400 nm or less. The substrate temperature depends on the heat resistance temperature of the substrate.
In the case of an ultraviolet laser, specifically, after film formation, for example, drying is performed at 100 ° C., and then the substrate temperature is set to room temperature, and ultraviolet laser irradiation is performed with low energy. In this case, it is desirable to perform laser irradiation in a range of 10 to ²⁰ mJ / cm ² in order to suppress a decrease in film thickness due to ablation and promote crystallization of vanadium oxide.
In the case of an ultraviolet lamp, after film formation, the substrate temperature is set to room temperature, and ultraviolet lamp irradiation is performed with low energy. In this case, in order to promote crystallization of vanadium oxide, it is desirable to irradiate with an ultraviolet lamp under a condition of 15 to 50 mW / cm ² .
In the present invention, when aiming at shortening the film formation time, it is preferable to crystallize the thin film by irradiating it with an ultraviolet lamp for a short time and then irradiating it with an ultraviolet laser.

Next, in the manufacturing method of the present invention, a protective layer made of an amorphous alumina thin film is provided on the first phosphor crystal thin film.
As a method for forming a protective layer made of an amorphous alumina thin film, an organic compound containing Al (ions) may be made into a solution, applied onto the first oxide phosphor crystal thin film, and then made amorphous after film formation. .
Examples of the organic compound containing aluminum generally include β-diketonato, a long-chain organic acid salt having 6 or more carbon atoms (which may contain a halogen), and the like containing these elements. Specific examples include naphthenate, 2-ethylhexanoate, acetylacetonato salt, and the like.
When the Al-containing compound is used as a solution for forming a thin film, a solvent such as toluene / xylene may be used if necessary. Then, this solution is formed on the first oxide phosphor crystal thin film by an appropriate method. The film forming method is not limited, and sputtering, MBE, vacuum deposition, CVD, chemical solution method (coating pyrolysis method, spray method) and the like are appropriately used.
Next, after the formed thin film is maintained at a temperature of 25 ° C. to 150 ° C., it is irradiated with an ultraviolet lamp or an ultraviolet laser having a wavelength of 400 nm or less.
In the case of an ultraviolet lamp, the substrate temperature is set to room temperature after film formation, and ultraviolet lamp irradiation is performed with low energy. In this case, it is desirable to irradiate with an ultraviolet lamp under a condition of 30 to 50 mW / cm ² in order to promote the decomposition of the organic matter.
In the case of an ultraviolet laser, specifically, after film formation, for example, drying is performed at 100 ° C., and then the substrate temperature is set to room temperature, and ultraviolet laser irradiation is performed with low energy. In this case, it is desirable to perform laser irradiation in the range of 5 to ²⁰ mJ / cm ² in order to suppress a decrease in film thickness due to ablation. Further, in the present invention, when aiming at shortening the film forming time, it is preferable to irradiate the thin film with an ultraviolet lamp for a short time and then irradiate with an ultraviolet laser to make it amorphous.

  Next, in the manufacturing method of the present invention, a second oxide phosphor thin film is provided on the amorphous aluminum oxide serving as the protective layer.

  In order to provide the second oxide phosphor crystal thin film on the amorphous alumina thin film, for example, a coating film having a metal composition of the oxide phosphor is provided on the amorphous alumina thin film, and the coating film has a wavelength of 400 nm or less. Then, a film having a metal composition of an oxide phosphor is physically vapor-deposited on the amorphous alumina thin film, and then an ultraviolet lamp having a wavelength of 400 nm or less is applied to the vapor-deposited film. Irradiation with an ultraviolet laser is sufficient.

Hereinafter, a method of forming a CaTiO ₃ : Pr ³⁺ phosphor thin film on an amorphous aluminum oxide layer will be described as an example in which a CaTiO ₃ : Pr ^{3 +} red phosphor is used as the second oxide phosphor.
First, an organic compound containing Ca, Ti, and Pr (ions) is made into a solution and applied onto amorphous aluminum oxide. Examples of organic compounds generally include β-diketonato, long-chain organic acid salts having 6 or more carbon atoms (which may contain halogen), and the like containing these elements. Specific examples include naphthenate, 2-ethylhexanoate, and acetylacetonate. The compound containing Ca, Ti, and Pr is used as a solution for forming a thin film. In this case, a solvent such as toluene / xylene may be used if necessary. Subsequently, this solution is formed into an organic metal thin film on a substrate by an appropriate method. In this case, in order to produce a high-quality film that easily reacts with an oxide, it is necessary to quickly form a film after preparing the solution (after mixing an organometallic solution containing Ca, Ti, and Pr). A desirable film forming method is not limited, and sputtering, MBE, vacuum deposition, CVD, chemical solution method (coating pyrolysis method, spray method) and the like are appropriately used.
Next, the formed thin film is kept at a temperature of 25 ° C. to 150 ° C., and then irradiated with an ultraviolet laser or an ultraviolet lamp having a wavelength of 400 nm or less.
In the case of an ultraviolet laser, specifically, after film formation, the substrate is dried at, for example, 100 ° C., and then the substrate temperature is set to room temperature. In this case, laser irradiation must be performed in the range of 5 to ²⁰ mJ / cm ² in order to suppress a decrease in film thickness due to ablation and promote the formation of an amorphous state. Subsequently, laser irradiation is performed in the range of 120 to 180 mJ / cm ² for crystallization. In order to prevent damage due to instantaneous heating due to laser heating to the lower layer, the number of shots should be limited to about 20 to 50 pulses. Moreover, in this invention, it is preferable to perform the process which irradiates an ultraviolet lamp to a thin film for a short time before laser irradiation.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, an Example does not restrict | limit this patent content.

Example 1
An RbVO ₃ thin film prepared on a PET substrate was spin-coated with an aluminum 2-ethylhexanoate toluene solution (C1 solution) at 3000 rpm for 10 seconds, and an ultraviolet lamp of 222 nm was applied in the atmosphere at an irradiation energy of 25 mW / cm ² for 10 minutes. After irradiation, the same 172 nm UV lamp was irradiated in the atmosphere at an irradiation energy of 38 mW / cm ² for 10 minutes. As a result, the organic component was decomposed to form an amorphous alumina thin film. From the PET / RbVO ₃ thin film / amorphous alumina thin film A laminate was obtained.

Example 2
In Example 1, when the irradiation energy of the 172 nm ultraviolet lamp was irradiated at 50 mW / cm ² , the irradiated layer was decomposed with organic components to form an amorphous alumina thin film, and a laminate similar to Example 1 was obtained.

Example 3
In Example 1, when an ultraviolet laser was irradiated at 10 mJ / cm ² after irradiation with the ultraviolet lamp, an amorphous alumina thin film was formed without causing laser ablation, and a laminate similar to Example 1 was obtained.

Example 4
On the amorphous alumina thin film of the laminate produced in Example 1, the metal composition ratio of 2-ethylhexanoic acid Ca, 2-ethylhexanoic acid Ti, and 2-ethylhexanoic acid Pr was 0.997: 1: 0.002. A solution diluted with toluene (C2 solution) was spin-coated at 3000 rpm for 10 seconds and irradiated with an ultraviolet lamp of 222 nm in the atmosphere at an irradiation energy of 25 mW / cm ² for 10 minutes. after irradiation with ultraviolet laser of 248nm in irradiation energy 20 mJ / cm ^2, was increased irradiation energy 170 mJ / cm ^2, on an amorphous alumina thin film red phosphor film _Ca 0.997 _Pr 0.002 TiO ₃ crystal And showed fluorescence by ultraviolet excitation. The fluorescent color was white with a lower color temperature mixed with red than that of RbVO ₃ alone.

Example 5
On the amorphous alumina thin film prepared in Example 1, the metal composition ratio of 2 ethyl hexanoic acid Ca, 2 ethyl hexanoic acid Sr, 2 ethyl hexanoic acid Ti, 2 ethyl hexanoic acid Pr was 0.648: 0.349: 1. : A solution (C3 solution) mixed at a ratio of 0.002 and diluted with toluene was spin-coated at 3000 rpm for 10 seconds, and irradiated with an ultraviolet lamp of 222 nm in the atmosphere at an irradiation energy of 25 mW / cm ² for 10 minutes. Similarly, after irradiating an ultraviolet laser of 248 nm in the atmosphere with an irradiation energy of 20 mJ / cm ² , the irradiation energy was increased to 170 mJ / cm ^{2. As} a result, a red phosphor film (Ca _0.65 Sr _{0. 35} ) A laminated phosphor obtained by crystallizing _0.997 Pr _0.002 TiO ₃ was obtained. This showed fluorescence by ultraviolet excitation. The fluorescent color was white with a lower color temperature mixed with red than that of RbVO ₃ alone. The manufacturing process flow of the (Ca _0.65 Sr _0.35 ) _0.997 Pr _0.002 TiO ₃ / amorphous Al ₂ O ₃ / RbVO ₃ / PET thin film obtained in Example 5 is shown in FIG. In addition, FIG. 2 shows a PL spectrum of this multilayer phosphor. The largest emission peak located near 525 nm is derived from RbVO ₃ , and the small peak around 375 nm is the emission of PET on the substrate. The emission peak in the vicinity of 610 nm is attributed to ¹ D ₂ → ³ H ₄ of Pr ₃₊ doped with red emission by (Ca _0.65 Sr _0.35 ) _0.997 Pr _0.002 TiO ₃ . The CIE chromaticity coordinate values also shown in the figure are x = 0.313 and y = 0.382, and RbVO _{3 /} PET (x = 0.305, y = 0.401) without forming the upper phosphor layer. ) (FIG. 3) is closer to pure white (x = 0.33, y = 0.33).

Comparative Example 1
An attempt was made to form the red phosphor shown in Example 4 directly on the RbVO ₃ film without forming the amorphous alumina thin film shown in Example 1, and when the irradiation energy of the ultraviolet laser was 20 mJ / cm ² , no crystallization occurred. When the irradiation energy was 80 mJ / cm ² , ablation occurred together with RbVO ₃ , and the PET substrate was burnt, so that a laminated phosphor could not be obtained.

Comparative Example 2
In Example 5, a phosphor composed of a PET / RbVO ₃ thin film was obtained without providing an amorphous alumina thin film and a red phosphor film (Ca _0.65 Sr _0.35 ) _0.997 Pr _0.002 TiO ₃ .
This showed fluorescence by ultraviolet excitation. The fluorescent color was white with a higher color temperature that did not mix red compared to the case where only RbVO ₃ was provided. The PL spectrum of this single-layer phosphor is shown in FIG.

Manufacturing process flow of Example 5 PL spectrum of (Ca _0.65 Sr _0.35 ) _0.997 Pr _0.002 TiO ₃ / Amorphous Al ₂ O ₃ / RbVO ₃ / PET thin film of Example 5 PL spectrum of single-layer phosphor (RbVO ₃ / PET) of Comparative Example 2

Claims (14)

  A laminated white phosphor in which an oxide white phosphor crystal thin film, an amorphous alumina thin film, and an oxide phosphor crystal thin film are sequentially provided on a substrate.   The laminated white phosphor according to claim 1, wherein the substrate is an organic substrate.   The multilayer white phosphor according to claim 1, wherein the oxide white phosphor is a vanadium oxide compound.   The stacked white phosphor according to claim 1, wherein the oxide phosphor produced on the top is a red phosphor or a blue phosphor.   2. The multilayer white phosphor according to claim 1, which emits white fluorescence having a fluorescence spectrum broadening in a range of 390 to 800 nm by ultraviolet / near ultraviolet light or ultraviolet / near ultraviolet excitation light emitting element.   After the substrate provided with the first oxide phosphor crystal thin film is kept at a temperature of room temperature to 150 ° C., an organic compound solution containing aluminum is applied to the surface, irradiated with ultraviolet light having a wavelength of 400 nm or less, and amorphous alumina The method for producing a laminated white phosphor according to any one of claims 1 to 5, wherein a thin film is formed and an oxide phosphor crystal thin film is formed thereon.   7. The method for producing a laminated white phosphor according to claim 6, wherein the ultraviolet light source is an ultraviolet laser or an ultraviolet lamp.   8. The method for producing a laminated white phosphor according to claim 7, wherein an ultraviolet laser is irradiated after irradiating with an ultraviolet lamp.   An oxide phosphor crystal thin film is formed by providing a coating film having a metal composition of an oxide phosphor on an amorphous alumina thin film, and irradiating the coating film with an ultraviolet lamp having a wavelength of 400 nm or less and then irradiating an ultraviolet laser. A method for producing a laminated white phosphor according to any one of claims 6 to 8.   A film having a metal composition of an oxide phosphor is physically vapor-deposited on the amorphous alumina thin film, and the oxide phosphor crystal thin film is formed by irradiating the vapor deposited film with an ultraviolet lamp having a wavelength of 400 nm or less and then with an ultraviolet laser. It forms, The manufacturing method of the lamination type white fluorescent substance in any one of Claims 6-8 characterized by the above-mentioned.   A white LED using the laminated white phosphor according to claim 1.   A display device using the laminated white phosphor according to any one of claims 1 to 5.   A lighting fixture using the laminated white phosphor according to any one of claims 1 to 5.   A display device using the laminated white phosphor according to any one of claims 1 to 5.