JP2002294230A - Aluminosilicate phosphor for vacuum ultraviolet excitation and vacuum ultraviolet excitation light emitting device using the phosphor - Google Patents

Abstract

(57) [Summary] (Modified) [Problem] Vacuum ultraviolet ray (VUV) with a wavelength of 200 nm or less
Provided are an aluminosilicate phosphor that emits ultraviolet rays with high efficiency by excitation, and a VUV-excited light-emitting device such as a rare gas lamp using the same. SOLUTION: An ultraviolet ray containing at least one kind of alkaline earth metal element of Ba, Sr or Ca, an Al element, a Si element and an Eu element, and having an emission spectrum peak in a 350 to 400 nm region under VUV excitation. An alkaline earth metal aluminosilicate phosphor of the following general formula that emits light, for example, Eu activated, (Ba _0.9 Eu _0.1 ) Al ₂ Si ₂
O ₈ and vacuum ultraviolet light emitting device using the phosphor _{(M 1-X Eu X)} O · aAl 2 O 3 · bSiO 2 (M is Ba, or more one Sr or Ca, x, a and b
Represents a number satisfying 0.005 ≦ x ≦ 0.2, 0.9 ≦ a ≦ 1.1, and 1.8 ≦ b ≦ 2.2. )

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alkaline earth which is excited by vacuum ultraviolet rays having a wavelength of 200 nm or less (hereinafter referred to as "VUV") and emits ultraviolet rays having an emission spectrum peak in a wavelength range of 350 to 400 nm. A VUV-excited light-emitting device (hereinafter referred to as “VUV”) comprising a class of aluminosilicate phosphors of a class of metals and a phosphor film using the phosphors
Excitation light emitting element ").

[0002]

2. Description of the Related Art A VUV-excited light-emitting device is provided with a fluorescent film containing a fluorescent substance in an envelope of an arbitrary shape made of glass or the like, and is sealed with the fluorescent film in Xe, Ne-X.
e, a rare gas such as He-Xe, He-Ne-Xe, etc. is discharged, and the wavelength radiated at that time is VUV of 200 nm or less.
To cause the fluorescent film to emit light. In the present invention, an apparatus having a function of exciting the fluorescent film in the envelope by the VUV generated by the discharge of the rare gas and emitting light by sealing the fluorescent film and the rare gas in the envelope as described above is provided. Collectively, they will be referred to as VUV excitation light emitting elements. This VU
As a typical example of the V excitation light emitting element, a plurality of phosphor films are arranged in a matrix to form a plurality of picture elements, and a light emission from each of these picture elements is combined and used as a display, such as a plasma display (PDP), There are illumination as a lamp that uses a phosphor film arranged in a plane and uses the light emission, and a rare gas lamp that is used as a light source, and development and improvement thereof have been actively performed in recent years.

By the way, fluorescent lamps that emit visible light have been mainly used for illumination and light sources.
In addition, ultraviolet radiation lamps that emit ultraviolet light have also been put to practical use for special purposes. A low-pressure mercury lamp is mainly used as the ultraviolet radiation lamp.

[0004] Applications of this ultraviolet radiation lamp include:
(i) to be used to artificially tan the skin to make it brown, (ii) to be used as a light source for dye fixation in copiers and printers using diazo photosensitive paper,
(iii) to be used in a skin disease treatment called PUVA (psoralen + ultraviolet A) therapy; (4) Ti
Antibacterial utilizing a photocatalyst such as O ₂ and ZnO, and use as an excitation light source in a sterilization system.

This lamp excites a phosphor in a coating film on the inner surface of a lamp tube by emitting mercury emission line having a wavelength of 254 nm generated by mercury discharge, and emits ultraviolet rays having a wavelength of 300 to 400 nm. BaSi ₂ O ₅ : Pb ²⁺ , SrB ₄ O are examples of phosphors that are excited by emission of mercury emission lines having a wavelength of 254 nm and efficiently emit ultraviolet rays.
7: Eu ²⁺ , CeMgAl ₁₁ O _{19 and the} like, and these phosphors are used as phosphors for ultraviolet radiation lamps.

As described above, low-pressure mercury lamps utilizing emission of a mercury emission line having a wavelength of 254 nm have been mainly used as the excitation light source as described above. However, in addition to the disadvantage that the luminous intensity of the low-pressure mercury lamp varies greatly depending on the ambient temperature, in recent years,
Due to concerns about the effect of mercury on the environment, the market tends to desire a mercury-free ultraviolet radiation lamp, and a rare gas lamp has been attracting attention to satisfy such a demand.

The rare gas lamp is a V.sub.V having a wavelength of 200 nm or less generated by discharge of a rare gas such as a single gas such as Xe or Ne or a mixed gas thereof filled in a lamp tube.
The phosphor is excited by UV to obtain desired fluorescence. However, rare gas lamps use VUV having a wavelength of 200 nm or less to excite the phosphor (eg, 147 nm and 172 nm VUV when Xe gas is discharged). Even if the body is applied to a rare gas lamp, efficient ultraviolet light emission cannot always be obtained. Therefore, development of a phosphor that emits ultraviolet rays with high efficiency by VUV excitation has been urgently required as a phosphor for an ultraviolet radiation rare gas lamp.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides an aluminosilicate phosphor which emits ultraviolet rays with high efficiency by VUV excitation at a wavelength of 200 nm or less, and a rare gas lamp using the phosphor. The first object is to provide a VUV excitation light emitting device.

[0009]

Means for Solving the Problems The present inventors have synthesized various phosphorates mainly based on oxyacid salts, and intensively examined the presence or absence of ultraviolet light emission and the light emission intensity by irradiating VUV having a wavelength of 200 nm or less with VUV. As a result, a phosphor of high efficiency ultraviolet emission having a peak wavelength of 360 to 390 nm can be obtained by using an alkaline earth metal aluminosilicate as a host crystal and activating Eu element thereto. The present inventors have found that a VUV-excited light-emitting device can be obtained by using this phosphor as a phosphor film, and have completed the present invention.

That is, the present invention has the following constitution. (1) At least one kind of alkaline earth metal element, Al element, Si element and E selected from the group consisting of Ba, Sr and Ca
and an aluminium alkaline earth metal for vacuum ultraviolet excitation characterized by exhibiting ultraviolet emission having an emission spectrum peak in a wavelength range of 350 to 400 nm when excited by vacuum ultraviolet light having a wavelength of 200 nm or less, respectively. Silicate phosphor.

(2) The alkaline earth metal aluminosilicate phosphor according to the above (1), wherein the alkaline earth metal aluminosilicate phosphor is represented by the following general formula: body. _{(M 1-x Eu x)} O · aAl 2 O 3 · bSiO 2 ( where, M represents at least one alkaline earth metal element selected from the group consisting of Ba, Sr and Ca, x, a and b is 0.005 ≦ x ≦ 0.2, 0.9 ≦ a ≦
1.1 and 1.8 ≦ b ≦ 2.2. )

(3) x in the above general formula is 0.01 ≦ x ≦
0.1, wherein the number satisfies the condition of 0.1.
(2) The alkaline earth metal aluminosilicate phosphor for excitation with vacuum ultraviolet light as described in (2). (4) the alkaline earth metal aluminosilicate phosphor,
The alkaline earth metal aluminosilicate phosphor for vacuum ultraviolet excitation according to any one of the above (1) to (3), wherein the crystal system has a crystal having a hexagonal structure as a main phase. .

(5) A vacuum ultraviolet ray excited light emitting device having a fluorescent film in an envelope and emitting light by emitting the fluorescent film by the discharge of a rare gas sealed in the envelope. Contains the alkaline earth metal aluminosilicate phosphor according to any one of the above (1) to (4).

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The phosphor of the present invention comprises at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca, an alkaline earth element comprising Al and Si as constituent elements. Metal aluminosilicate is used as a host crystal, and is an alkaline earth metal aluminosilicate phosphor containing Eu as an activator, absorbing VUV having a wavelength of 200 nm or less and having a peak wavelength of 360 to 390 nm. Is radiated with high efficiency.

To produce the alkaline earth metal aluminosilicate phosphor of the present invention, at least one alkaline earth metal element selected from the group consisting of Ba, Sr and Ca;
Oxides, carbonates, nitrates, oxalates, etc. of each of the Al element, Si element and Eu element are weighed so that the compound of each element has the desired chemical composition stoichiometrically and mixed well. To prepare a phosphor material. This is filled in a heat-resistant container such as an alumina crucible, and fired at least once in a reducing atmosphere at a temperature in the range of 1100 to 1600 ° C. for 1 to 10 hours to disperse the obtained fired product. It can be obtained by a usual method for producing a phosphor, such as washing with water, drying and sieving. The firing may be performed in a neutral atmosphere. Preferred firing conditions are firing in a reducing atmosphere at 1150 to 1450 ° C. for 2 to 5 hours. When firing multiple times, it is necessary to perform firing at least once in a reducing atmosphere. Also, in the phosphor raw material,
It is more preferable to mix and bake a flux as a reaction accelerator, for example, NH ₄ Cl, since the ultraviolet emission intensity of the phosphor can be increased.

The alkaline earth metal aluminosilicate phosphor of the present invention has a composition formula represented by the following formula, and most of the crystals have a hexagonal structure, and the ultraviolet rays when excited by VUV are used. A phosphor having a high emission intensity can be obtained. _{(M 1-x Eu x)} O · aAl 2 O 3 · bSiO 2 ( where, M represents at least one alkaline earth metal element selected from the group consisting of Ba, Sr and Ca, x, a and b is 0.005 ≦ x ≦ 0.2, 0.9 ≦ a ≦
1.1 and a number that satisfies the condition of 1.8 ≦ b ≦ 2.2. )

In this composition, for example, when the alkaline earth metal element M is Ba and a = 1 and b = 2, the base material of the phosphor has a composition formula of BaAl ₂ Si ₂ O ₈ (= BaO · A
is represented by _{l 2 O 8 · 2SiO 2)} , Ba in the host crystal
Light is emitted by substituting a part of the position with divalent Eu as an activator. However, if the amount of Eu substitution is excessively increased, the intensity of ultraviolet light emission decreases. On the other hand, if the amount of Eu substitution is too small, the amount of luminescent centers is insufficient, and the luminous intensity is reduced. When the above phosphor was manufactured by changing the Eu substitution amount and the emission intensity was examined, the Eu substitution amount (x value) was 0.005.
It has been found that when adjusted to the range of ≦ x ≦ 0.2, it is excited with VUV and emits ultraviolet rays with high efficiency. Note that E
A more preferable range of the u substitution amount (x value) is 0.01 ≦ x ≦
0.1.

FIG. 1 shows that the composition formula is (Ba _0.95 Eu _0.05 ) Al
FIG. 3 illustrates a powder X-ray diffraction pattern of the barium aluminosilicate phosphor of the present invention, which is ₂ Si ₂ O ₈ , by a characteristic X-ray of CuKα.
By comparing the diffraction pattern with that of No.-0726), it was confirmed that the crystal composition was a hexagonal crystal having the above composition formula.

FIG. 2 shows that the composition formula is (Ba _0.95 Eu _0.05 ) Al
FIG. 3 is a diagram illustrating an emission spectrum when the alkaline earth metal aluminosilicate phosphor of the present invention, which is ₂ Si ₂ O ₈ , is excited by VUV having a wavelength of 146 nm. As is clear from FIG. 2, when the above-described phosphor is excited by VUV having a wavelength of 146 nm, the peak wavelength is around 370 nm, and the phosphor emits ultraviolet light having a very sharp emission spectrum distribution. The emission spectrum of this phosphor shows light emission having a spectrum distribution substantially similar to that of FIG. 2 even when excited by VUV having a wavelength of 172 nm.

FIG. 3 shows that the composition formula is (Ba _0.95 Eu _0.05 ) Al
FIG. 3 is a diagram illustrating an excitation spectrum of the alkaline earth metal aluminosilicate phosphor of the present invention, which is ₂ Si ₂ O ₈ , from the VUV region to the ultraviolet region. The horizontal axis of FIG. 3 is the wavelength of VUV or ultraviolet light applied to the phosphor, and the relative quantum efficiency of the vertical axis is the emission intensity and sodium salicylate when the phosphor is irradiated with VUV or ultraviolet light of each wavelength. Is measured as a relative value when the quantum efficiency of light emission of sodium salicylate having a constant quantum efficiency in the wavelength range of 120 to 300 nm is set to 100.

As is clear from FIG. 3, the phosphor of the present invention has a wavelength of 120 to 120 nm outside the ultraviolet wavelength range of 200 to 300 nm.
It can be seen that high quantum efficiency is maintained over the VUV wavelength range of 200 nm. In the alkaline earth metal aluminosilicate phosphor of the present invention, the alkaline earth metal M is B
Even when Sr or Ca other than a was used, it was confirmed that the emission spectrum when excited with VUV having a wavelength of 200 nm or less showed emission having a spectrum distribution substantially similar to that of FIG.

The VUV-excited light-emitting device of the present invention can be manufactured in exactly the same manner as the conventional VUV-excited light-emitting device except that the above-mentioned alkaline earth metal aluminosilicate phosphor of the present invention is used as the fluorescent film. . For example, a method of manufacturing the VUV excitation light emitting device of the present invention using a rare gas as an example will be described. A fluorescent film made of the above alkaline earth metal aluminosilicate phosphor is formed inside a glass tube, The lamp can be manufactured in a conventional manner. That is, the above alkaline earth metal aluminosilicate phosphor and ethyl cellulose, nitrocellulose, polyethylene oxide, a binder resin such as an acrylic resin,
A phosphor paste composition obtained by mixing water, butyl acetate, butyl carbitol, a solvent such as terpineol and kneading well to adjust to a predetermined viscosity is applied to the inner wall of a glass tube, dried and baked. Then, a fluorescent film is formed on the inner wall of the glass tube, electrodes are formed on the inner and outer sides or on the outer surface of the glass tube with the glass tube at both ends sandwiched, one end of the glass tube is sealed, the inside is evacuated, and then Xe, Xe- After encapsulating a rare gas such as Ne, the glass tube is completely sealed to obtain an ultraviolet radiation rare gas lamp.

When PDP is used, the above-mentioned alkaline earth aluminosilicate phosphor of the present invention is dispersed in an organic solvent containing a binder resin and kneaded to prepare a phosphor paste composition. A PDP that emits ultraviolet rays is obtained in the same manner as a conventional PDP, except that a phosphor film is formed by printing and applying the resultant to a predetermined location of a cell of the PDP by a screen printing method or the like. In this case, for example, instead of the alkaline earth metal aluminosilicate phosphor of the present invention, for example, the alkaline earth metal aluminosilicate phosphor of the present invention and visible light excited by ultraviolet rays emitted from the phosphor are used. If a phosphor film is formed in the same manner using a phosphor mixed with a phosphor capable of emitting light, a PDP that emits visible light can be obtained.

[0024]

Next, the present invention will be described by way of examples. (Example 1) BaCO ₃ 0.9 mol Eu ₂ O ₃ 0.05 mol Al ₂ O ₃ 1 mol SiO ₂ 2 mol A raw material compound obtained by sufficiently mixing the above phosphor raw materials is filled in an alumina crucible, and a reducing atmosphere is used. Inside, maximum temperature 1300 ℃
For 2 hours. The calcined product is subjected to dispersion, washing, drying, and sieving, and the crystal system is hexagonal and the composition is (Ba _0.9 Eu _0.1 ) Al ₂ Si as viewed from the powder X-ray diffraction diagram.
A Eu activated aluminosilicate phosphor of ₂ O ₈ was obtained. When this phosphor was irradiated with VUV having a wavelength of 146 nm, it emitted ultraviolet light having a peak wavelength of an emission spectrum of 372 nm.

Examples 2 to 4 In Example 1, the NH ₄ Cl flux was 0.235 mol, 0.392 mol and 0.784 mol, respectively, per mol of Al ₂ O ₃ in the phosphor raw material. Examples 2 to 4 in which the crystal system was a hexagonal system were the same as in Example 1 except that they were added by mole and mixed well.
Eu-activated aluminosilicate phosphor [(Ba _0.9 E
u _0.1 ) Al ₂ Si ₂ O ₈ ] was obtained. E of Examples 2 to 4
When the u-activated aluminosilicate phosphor was irradiated with VUV of 146 nm under the same conditions as in Example 1, the peak wavelengths of the emission spectra exhibited ultraviolet light emission having the wavelengths shown in Table 1, respectively. The intensity at the peak wavelength of Example 1 was examined, and the relative emission intensity when the intensity at the peak wavelength of the phosphor of Example 1 was set to 100 is shown in Table 1.

[0026]

[Table 1]

Examples 5 to 8 In the same manner as in Example 1 except that the compounding ratio of the starting compounds was changed as shown in Table 2, the Eu of Examples 5 to 8 in which the crystal system was a hexagonal system was used. An activated aluminosilicate phosphor was obtained. The phosphor composition is shown in Table 3. When the Eu-activated aluminosilicate phosphors of Examples 5 to 8 were irradiated with 146 nm VUV under the same conditions as in Example 1, the peak wavelengths of the emission spectra exhibited ultraviolet light emission having the wavelengths shown in Table 3 respectively. The intensity at the peak wavelength of the emission spectrum at that time was examined.
Table 3 shows the relative luminescence intensity together with the peak wavelength when the intensity of the phosphor at the peak wavelength was taken as 100.

[0028]

[Table 2]

[0029]

[Table 3]

Examples 9 to 10 In the same manner as in Example 1 except that the compounding ratios of the raw material compounds were changed as shown in Table 4, the Eu-added materials of Examples 9 to 10 in which the crystal system was hexagonal were used. An active aluminosilicate phosphor was obtained. Table 5 shows the phosphor composition.
It was shown to. The Eu-activated aluminosilicate phosphors of Examples 9 to 10 were compared with the VUV of 146 nm under the same conditions as in Example 1.
Was irradiated, the peak wavelength of the emission spectrum exhibited ultraviolet light emission having the wavelengths shown in Table 5, respectively. The intensity at the peak wavelength of the emission spectrum at that time was examined, and the intensity at the peak wavelength of the phosphor of Example 1 was measured. Table 5 shows the relative luminescence intensity with the peak wavelength at 100.

[0031]

[Table 4]

[0032]

[Table 5]

[0033]

According to the present invention, by adopting the above-described structure, the excitation with VUV having a wavelength of 200 nm or less and the wavelength of 30
It is possible to provide an alkaline earth aluminosilicate phosphor that emits ultraviolet rays of 0 to 400 nm and has excellent emission intensity, and in particular, an excellent ultraviolet light emitting rare gas lamp when applied to a fluorescent film of a rare gas lamp. Made possible.

[Brief description of the drawings]

FIG. 1 shows (Ba _0.95 Eu _0.05 ) Al ₂ Si ₂ O of the present invention
_It shows the X-ray diffraction pattern of ₈ phosphors.

FIG. 2 shows (Ba _0.95 Eu _0.05 ) Al ₂ Si ₂ O of the present invention.
₈ is an emission spectrum when ₈ phosphors are excited by 146 nm vacuum ultraviolet light.

FIG. 3 shows (Ba _0.95 Eu _0.05 ) Al ₂ Si ₂ O of the present invention.
₈ is an excitation spectrum of ₈ phosphors in a vacuum ultraviolet wavelength range to an ultraviolet wavelength range.

FIG. 4 is a diagram showing a correlation between the activator (Eu) content (x) and the peak intensity of the emission spectrum in the alkaline earth metal aluminosilicate phosphor of the present invention.

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Claims (4)

[Claims] At least one kind of alkaline earth metal element, Al element and S selected from the group consisting of Ba, Sr and Ca
each containing an i element and an Eu element and having a wavelength of 200 nm
An alkaline earth metal aluminosilicate phosphor for excitation with vacuum ultraviolet light, which emits ultraviolet light having an emission spectrum peak in a wavelength range of 350 to 400 nm under the following excitation with vacuum ultraviolet light. 2. The alkaline earth metal aluminosilicate phosphor for vacuum ultraviolet excitation according to claim 1, wherein the alkaline earth metal aluminosilicate phosphor is represented by the following general formula. _{(M 1-x Eu x)} O · aAl 2 O 3 · bSiO 2 ( where, M represents at least one alkaline earth metal element selected from the group consisting of Ba, Sr and Ca, x, a and b is 0.005 ≦ x ≦ 0.2, 0.9 ≦ a ≦
1.1 and 1.8 ≦ b ≦ 2.2. ) 3. The alkaline earth metal for excitation with vacuum ultraviolet radiation according to claim 2, wherein the alkaline earth metal aluminosilicate phosphor has a crystal having a hexagonal crystal system as a main phase. Metal aluminosilicate phosphor. 4. A vacuum ultraviolet light emitting device having a fluorescent film in an envelope and emitting the fluorescent film by being excited by discharge of a rare gas sealed in the envelope, wherein the fluorescent film is A vacuum ultraviolet-excitation light-emitting device comprising the alkaline earth metal aluminosilicate phosphor according to claim 1.