JP2001354957A - Aluminate phosphor and fluorescent lamp using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable aluminate phosphor capable of improving emission strength while maintaining good color purity. SOLUTION: The aluminate phosphor is represented by the formula: (Ce, Tb) (Mg1-a-bZnaMnb)Al2zO2.5+3z.ySiO2 (wherein 0<a<=0.6; 0<a+b<1; 0<y<=1.0; and 4.5<=z<=8).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminate phosphor and a fluorescent lamp using the same.

[0002]

2. Description of the Related Art In recent years, large-sized color image display devices that can be used outdoors have been developed and are being widely used. Japanese Patent Application Laid-Open Nos. 61-55851 and 2-129847 disclose a flat emission type variable color fluorescent lamp used for pixels and the like of such a large display. These variable-color fluorescent lamps are composed of one or more sets of picture elements that emit monochromatic light from phosphors emitting G (green), R (red), and B (blue), respectively, in order to form pixels of a large display. Have been. Among these phosphors, for example, terbium-activated cerium magnesium aluminate (hereinafter referred to as CAT) is used as the G component phosphor.

However, G component phosphors used in conventional flat light emitting fluorescent lamps for large displays include:
Since light emission by trivalent terbium is used as represented by CAT, as shown in FIG. 3, the color purity of green is not satisfactory, and the color reproduction range is narrower than that of a general color television. There was a problem, and improvement was desired. In FIG. 3, the R component phosphor is yttrium oxide (denoted as YOX in FIG. 3) activated with trivalent europium, and the B component phosphor is barium magnesium aluminate activated with divalent europium. (Also referred to as BAM).

For this reason, divalent manganese light emission is suitable as a phosphor having good color purity of green light emission, and divalent manganese-activated zinc silicate, divalent europium and divalent manganese are suitable for fluorescent lamps. Co-activated barium magnesium aluminate with manganese, divalent manganese activated cerium magnesium aluminate, and divalent manganese and 3
Cerium magnesium aluminate co-activated with monovalent terbium is known.

[0005] However, the above-described conventional flat light emitting fluorescent lamps for large displays are usually operated under high load, so that divalent manganese-activated zinc silicate and divalent europium and divalent manganese are used. In the case of co-activated barium magnesium aluminate, the luminance retention rate during the life is inferior,
In the case of divalent manganese-activated cerium magnesium aluminate and co-activated cerium magnesium aluminate of divalent manganese and trivalent terbium, the luminance retention rate during the lifetime is good, but the luminance itself is low. There was a disadvantage of being low.

Therefore, in order to improve the luminance of divalent manganese-activated cerium magnesium aluminate, an aluminate phosphor in which a part of magnesium is replaced with barium, strontium, calcium or zinc has been known (Patent). No. 2663306).

It is also known that co-activated cerium magnesium aluminate of divalent manganese and trivalent terbium is partially replaced with zinc in order to improve the luminance ( Patent No. 28946
No. 54).

The aluminate phosphors disclosed in Japanese Patent No. 2663306 and Japanese Patent No. 2894654 are used not only in flat-emitting fluorescent lamps for large displays but also in fluorescent lamps for general lighting. Is also used.

[0009]

However, in such a conventional aluminate phosphor, even when a part of magnesium is replaced with a divalent metal element, these two aluminate phosphors may be used.
Divalent metal element is hardly dissolved in the phosphor crystal stably,
As a result, there is a problem that a sufficient light emission intensity cannot be obtained. In particular, when zinc is used as the divalent metal element,
The amount of solid solution fluctuates greatly.

In the conventional fluorescent lamp having a phosphor film made of an aluminate phosphor, as described above, the divalent metal element is hardly dissolved in the phosphor crystal as a solid solution.
There is a problem that a sufficient luminous flux and a luminance maintenance rate during the life cannot be obtained.

The present invention has been made to solve such a problem, and is particularly suitable as a fluorescent material used for a flat light emitting fluorescent lamp for a large display, a fluorescent lamp for general lighting, and the like. It is an object of the present invention to provide a stable aluminate phosphor capable of improving emission intensity while maintaining color purity.

Further, the present invention can improve the luminous flux while maintaining good color purity, particularly in a flat light emitting fluorescent lamp for a large display, a fluorescent lamp for general lighting, and the like, and can improve the life span. And to provide a fluorescent lamp with less reduction in luminance.

[0013]

The aluminate phosphor of the present invention has a general formula: (Ce, Tb) (Mg _1-ab Zn _a Mn)
_b ) Al _2z O _{2.5 +} 3z.ySiO ₂ (where 0 <a ≦ 0.
6, 0 <a + b <1, 0 <y ≦ 1.0, 4.5 ≦ z ≦ 8
Which satisfies the following condition).

Thus, silicon dioxide can be solid-dissolved during the synthesis of the phosphor, and zinc in which a part of magnesium has been substituted can be stably dissolved in the phosphor crystal, so that good color purity can be maintained while maintaining good color purity. The emission intensity can be improved.

Further, the fluorescent lamp of the present invention has a structure provided with a phosphor film containing the aluminate phosphor of the first aspect.

[0016] As a result, since the zinc partially substituted for magnesium is stably dissolved in the crystal of the phosphor, the luminous flux can be improved while maintaining good color purity, and the lifetime can be improved. Through this, a decrease in luminance can be suppressed.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FCL according to an embodiment of the present invention
The 30/28 fluorescent lamp has a tube diameter of 29, as shown in FIG.
The glass bulb 1 is provided with stems 2 sealed at both ends of the glass bulb 1.

In FIG. 1, reference numeral 3 denotes a base.

The glass bulb 1 is filled with a predetermined amount of mercury and a rare gas such as argon. Further, a phosphor film 4 is formed on the inner surface of the glass bulb 1.

The stem 2 has a filament 6 laid between two lead wires 5 (only one is shown).

The phosphor film 4 is a G (green) component phosphor.
And the general formula: (Ce, Tb) (Mg _1-abZn_aMn_b)
Al_2zO_{2.5 + 3z}・ YSiO_Two(However, 0 <a ≦ 0.
6, 0 <a + b <1, 0 <y ≦ 1.0, 4.5 ≦ z ≦ 8
Which satisfies the condition)
The light body is an R (red) component phosphor, for example, YOX
As a B (blue) component phosphor, for example, BAM
It is composed of a mixed phosphor mixed respectively.

In the above general formula representing the aluminate phosphor as the G component phosphor, a represents the substitution amount of zinc (Zn) for partially substituting magnesium (Mg), and b represents manganese as the activator. The concentration of (Mn) is shown. The ranges are 0 <a ≦ 0.6, 0 <b <0.4 (0 <a +
b <1). If the substitution amount a of zinc exceeds 0.6, the formation of regular phosphor crystals is inhibited, and the emission intensity is reduced. When the manganese concentration b is 0.4 or more,
Emission intensity is reduced due to concentration quenching.

Y indicates the amount (mol ratio) of silicon dioxide (SiO ₂ ) to be added, and is defined in the range of 0 <y ≦ 1.0. In particular, y is preferably defined in the range of 0.01 ≦ y ≦ 0.5. Details of the reason will be described later.

Further, z is aluminum oxide (Al
_It indicates the composition ratio of ₂ O ₃ ) and is specified in the range of 4.5 ≦ z ≦ 8.

Next, a method for producing such an aluminate phosphor will be described.

The phosphor raw material includes at least one cerium compound selected from cerium compounds such as cerium oxide and cerous nitrate as a cerium source, and a terbium compound such as terbium oxide and terbium nitrate as a terbium source. At least one selected from the group consisting of basic magnesium carbonate as a magnesium source,
Magnesium hydroxide, at least one selected from magnesium compounds such as magnesium fluoride, at least one selected from zinc compounds such as zinc oxide and zinc chloride as a zinc source, and a manganese compound such as manganese carbonate as a manganese source And at least one selected from aluminum compounds such as aluminum oxide and aluminum hydroxide as an aluminum source, and at least one selected from silicon compounds such as silicon oxide as a silicon source.

A predetermined amount of these raw materials is weighed and mixed well. Put this mixture in a crucible and in air at 1200 ° C
Bake at １1600 ° C. for 2-4 hours. After the obtained fired product is pulverized, it is again put into a crucible and fired at 1400 ° C. to 1600 ° C. for another 2 to 4 hours in a reducing atmosphere of a mixed gas of nitrogen and hydrogen (nitrogen; 95%, hydrogen; 5%). I do. The burned material is subjected to a treatment such as grinding and washing with water to obtain the aluminate phosphor of the present invention which emits green light.

In the above method for producing an aluminate phosphor, fluorides such as aluminum fluoride, ammonium chloride, and magnesium fluoride, which are well known as a flux material used for the rare earth aluminate phosphor, or boric acid It was found that the addition of boron oxide or boron oxide was effective in improving the emission intensity as described below if it was in an appropriate amount.

The above general formula: (Ce, Tb) (M
g _1-ab Zn _{a M} n _b ) Al _2z O _{2.5 + 3 z} · ySiO ₂ (where 0 <a ≦ 0.6, 0 <a + b <1, 0 <y ≦ 1.
0, 4.5 ≦ z ≦ 8) according to the aluminate phosphor represented by the formula (1), when replacing a part of magnesium with zinc, silicon dioxide is dissolved during the production of the phosphor. By doing so, the solid solution of zinc can be stabilized, and as a result, the emission intensity can be improved while maintaining good color purity.

According to the fluorescent lamp having the phosphor film containing the aluminate phosphor of the present invention, zinc in which magnesium is partially substituted is stably dissolved in the crystal of the phosphor. Therefore, the luminous flux can be improved while maintaining good color purity, and a decrease in luminance can be suppressed throughout the life.

An experimental example for confirming the operation and effect of the present invention will be described below.

Example 1 The composition formula of the aluminate phosphor of Example 1 is Ce _0.6 Tb _0.4 (Mg _0.68 Zn _0.3 Mn).
_0.02 ) Al ₁₁ O ₁₉ · 0.5 SiO ₂ . The materials of the aluminum hydrochloride phosphor of Example 1 are as follows. CeO ₂ 0.60 mol Tb ₄ O ₇ 0.10 mol Mg (OH) ₂ 0.68 mol ZnO 0.30 mol Al ₂ O ₃ 5.50 mol SiO ₂ 0.50 mol MnCO ₃ 0.02 mol Aluminate fluorescence of Example 1 luminous intensity by 254nm ultraviolet excitation body, aluminate contains no silicon dioxide phosphor _{Ce 0.6 Tb 0.4 (Mg 0.68 Zn} 0. 3 Mn
_0.02 ) It was found that the emission intensity was improved by 10% as compared with the emission intensity of Al ₁₁ O ₁₉ (hereinafter referred to as Comparative Example 1).

The FCL 30/28 fluorescent lamp manufactured by using the aluminate phosphor of Example 1 was used.
The luminous flux after the elapse of the time lighting was 10% of the FCL30 / 28 fluorescent lamp manufactured using the aluminate phosphor of Comparative Example 1.
It was found that the luminous flux was improved by 7% as compared with the luminous flux after lighting for 0 hours.

Further, the luminance retention rate of the FCL30 / 28 fluorescent lamp using the aluminate phosphor of Example 1 after the lapse of 2,000 hours of lighting was determined by the FCL30 / 28 fluorescence using the aluminate phosphor of Comparative Example 1. It was found that the luminance was improved by 2% as compared with the luminance maintenance ratio after the lamp was lit for 2000 hours.

As described above, in the fluorescent lamp using the aluminate phosphor of Example 1, the characteristics of the luminous flux and the luminance maintenance ratio can be clearly improved.

Example 2 The composition formula of the aluminate phosphor of Example 2 is Ce _0.8 Tb _0.2 (Mg _0.85 Zn _0.05 Mn).
_0.1 ) Al ₁₅ O ₂₅ · 0.05SiO ₂ . The materials of the aluminate phosphor of Example 2 are as follows. _{Ce 2 (NO 3) 3 ·} 6H 2 O 0.40mol Tb 4 O 7 0.05mol MgO 0.85mol ZnCO 3 0.05mol Al 2 O 3 7.50mol SiO 2 0.05mol MnF 2 0.10mol this embodiment luminous intensity by 254nm UV excitation aluminate phosphor of 2, aluminate contains no silicon dioxide phosphor _{Ce 0.8 Tb 0.2 (Mg 0.85 Zn} 0. 05 Mn
_0.1 ) It was found to be 14% higher than the emission intensity of Al ₁₅ O ₂₅ (hereinafter referred to as Comparative Example 2).

The FCL 30/28 fluorescent lamp manufactured by using the aluminate phosphor of Example 2 is 100%.
The luminous flux after the elapse of the time lighting was 10% of the FCL30 / 28 fluorescent lamp manufactured using the aluminate phosphor of Comparative Example 2.
It was found that the luminous flux was improved by 10% as compared with the luminous flux after lighting for 0 hours.

Further, the luminance retention ratio of the FCL30 / 28 fluorescent lamp using the aluminate phosphor of Example 2 after the lapse of 2,000 hours of lighting was determined by the FCL30 / 28 fluorescent lamp using the aluminate phosphor of Comparative Example 2. It was found that the luminance was improved by 2% as compared with the luminance maintenance ratio after the lamp was lit for 2000 hours.

As described above, in the fluorescent lamp using the aluminate phosphor of the second embodiment, the characteristics of the luminous flux and the luminance maintenance ratio can be clearly improved.

Example 3 Aluminate Fluorescence of Example 3
The composition formula of the body is Ce_0.96Tb_0.04(Mg_0.35Zn_{0. Five}Mn
_0.15) Al_FifteenO_{twenty five}・ 0.03SiO_TwoIt is. Also,
The material of the aluminate phosphor of Example 3 is as follows:
It is a cage. Ce_Two(NO_Three)_Three・ 6H_TwoO 0.48mol Tb_FourO₇ 0.01mol MgO 0.35mol ZnCO_Three 0.50mol Al_TwoO_Three 7.50mol SiO_Two 0.03mol MnF_Two 0.15 mol 254 nm ultraviolet light of the aluminate phosphor of Example 3
The emission intensity by excitation is
Phosphate phosphor Ce_0.96Tb_0.04(Mg_0.35Zn _0.5Mn
_0.15) Al_FifteenO_{twenty five}(Hereinafter referred to as Comparative Example 3)
It was found to be improved by 7% as compared with.

The FCL 30/28 fluorescent lamp manufactured by using the aluminate phosphor of Example 3 is 100%.
The luminous flux after the elapse of the time lighting was 10% of the FCL30 / 28 fluorescent lamp manufactured using the aluminate phosphor of Comparative Example 3.
It was found that the luminous flux was improved by 4% as compared with the luminous flux after 0 hours of lighting.

Further, the luminance retention rate of the FCL30 / 28 fluorescent lamp using the aluminate phosphor of Example 3 after the lapse of 2,000 hours of lighting was determined by the FCL30 / 28 using the aluminate phosphor of Comparative Example 3. It was found that the luminance was improved by 1% as compared with the luminance maintenance rate after the lapse of 2000 hours of lighting of the fluorescent lamp.

As described above, in the fluorescent lamp using the aluminate phosphor of the third embodiment, the characteristics of the luminous flux and the luminance maintenance ratio can be clearly improved.

Example 4 Aluminate Fluorescence of Example 4
The composition formula of the body is Ce_0.64Tb_0.36(Mg_0.94Zn_{0. 01}Mn
_0.05) Al_TenO_17.5・ 0.003SiO_TwoIt is. Ma
The material of the aluminate phosphor of Example 4 was as follows.
It is shown. CeO_Two 0.64mol Tb_FourO₇ 0.09mol MgO 0.94mol ZnCO_Three 0.01mol Al_TwoO_Three 5.00mol SiO_Two 0.003mol MnF_Two 0.05 mol UV light of the aluminate phosphor of Example 4 at 254 nm
The emission intensity by excitation is
Phosphate phosphor Ce_0.64Tb_0.36(Mg_0.94Zn _0.01Mn
_0.05) Al_TenO_17.5(Hereinafter referred to as Comparative Example 4)
It was found to be improved by 5% compared to the degree.

The FCL 30/28 fluorescent lamp manufactured by using the aluminate phosphor of Example 4 was used.
The luminous flux after the elapse of the time lighting was 10% of the FCL30 / 28 fluorescent lamp manufactured using the aluminate phosphor of Comparative Example 4.
It was found that the luminous flux was improved by 3% as compared with the luminous flux after lighting for 0 hours.

Further, the luminance retention rate of the FCL30 / 28 fluorescent lamp using the aluminate phosphor of Example 4 after the lapse of 2,000 hours of lighting was determined by the FCL30 / 28 fluorescent lamp using the aluminate phosphor of Comparative Example 4. It was found that the luminance was improved by 1% as compared with the luminance maintenance ratio after the lamp was turned on for 2000 hours.

As described above, in the fluorescent lamp using the aluminate phosphor of the fourth embodiment, the characteristics of the luminous flux and the brightness maintenance ratio can be clearly improved.

Here, as the aluminate phosphor according to the present invention, for example, (Ce _0.6 Tb _0.4 ) (Mg _0.68 Zn
_{In 0.3} Mn _0.02 ) Al ₁₁ O ₁₉ .ySiO ₂ , a phosphor (Ce _0.6 Tb _0.4 ) which does not contain silicon dioxide, that is, y = 0, is obtained by changing the addition amount y of silicon dioxide.
When the relative luminous intensity (%) with respect to the luminous intensity of (Mg _0.68 Zn _0.3 Mn _0.02 ) Al ₁₁ O ₁₉ was examined, the results shown in Table 1 were obtained.

In Table 1, “○” indicates good,
“X” indicates a defect.

[0050]

[Table 1]

As shown in Table 1, when the addition amount y of silicon dioxide exceeds 0, for example, at 0.001, the relative emission intensity was 100.1%. On the other hand, when the addition amount y of silicon dioxide exceeds 1.0, for example, when the addition amount was 1.001, the relative emission intensity was 99.5%. Therefore,
The emission intensity can be improved by setting the amount y of silicon dioxide to be more than 0 and not more than 1.0.

Particularly, the addition amount y of silicon dioxide is
It is preferable that the light emission intensity is defined in the range of 0.01 or more and 0.5 or less, which can further improve the light emission intensity.

As an example of the aluminate phosphor according to the present invention, (Ce _0.6 Tb _0.4 ) (Mg _0.68 Zn _0.3 M
n _0.02 ) 2 of Al ₁₁ O ₁₉ .0.1 SiO ₂ (Example 1)
FIG. 2 shows an emission spectrum by excitation with a 54 nm ultraviolet ray. However, the vertical axis in FIG. 2 is the peak emission intensity (wavelength 54
The relative luminescence intensity (%) is shown with 4 nm) as 100.

FIG. 3 shows, for example, (Ce _0.6 Tb _0.4 )
(Mg _0.68 Zn _0.3 Mn _0.02 ) Al ₁₁ O ₁₉ · 0.5Si
₂ of the aluminate phosphor according to the present invention represented by O 2
The chromaticity point P of light emission by excitation of 54 nm ultraviolet light is determined by CA used in a conventional flat fluorescent lamp for a large display.
These are shown on the x and y coordinates together with those for T, YOX and BAM.

In FIG. 3, G, R, and B are chromaticity coordinates of the NTSC system used in a general color television.

As is apparent from FIG. 3, the aluminate phosphor according to the present invention has good color purity, and by combining it with conventional YOX and BAM, for example, can reproduce the same color as a general color television. It can be seen that it can be realized.

In the above embodiment, the case where the aluminate phosphor of the present invention is used for an FCL30 / 28 fluorescent lamp has been described. However, the aluminate phosphor of the present invention is not limited to this, and may be, for example, a straight tube. The same effects as described above can be obtained by using the present invention in a fluorescent lamp for general illumination such as a compact fluorescent lamp or a compact fluorescent lamp, or a flat light emitting fluorescent lamp for a large display.

In the above embodiment, the case where the phosphor film 4 containing the aluminate phosphor of the present invention is formed directly on the glass bulb 1 has been described. The same effect as described above can be obtained even if a protective film is formed on the substrate.

[0059]

As described above, the present invention can provide a stable aluminate phosphor capable of improving emission intensity while maintaining good color purity.

Further, the present invention can provide a fluorescent lamp which can improve the luminous flux while maintaining good color purity and has a small decrease in luminance throughout its life.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of an FCL30 / 28 fluorescent lamp according to an embodiment of the present invention.

FIG. 2 shows an emission spectrum of an aluminate phosphor according to one embodiment of the present invention.

FIG. 3 is a diagram showing the chromaticity of the aluminate phosphor shown in Example 1 of the present invention on an x, y chromaticity diagram.

[Description of Signs] 1 Glass bulb 2 Stem 3 Cap 4 Phosphor film 5 Lead wire 6 Filament

Claims (2)

[Claims] 1. A compound of the general formula: (Ce, Tb) (Mg _1-ab Z
_{n a Mn b) Al 2z O} 2.5 + 3z · ySiO 2 ( where 0 <
a ≦ 0.6, 0 <a + b <1, 0 <y ≦ 1.0, 4.5
≤ z ≤ 8). 2. A fluorescent lamp comprising a phosphor film containing the aluminate phosphor according to claim 1.