JPH0586366A - Aluminate of stimulable phosphor and fluorescent lamp prepared by using the same - Google Patents

Abstract

PURPOSE:To provide an aluminate of stimulable phosphor improved in the color purity of green and reduced in luminance loss throughout its life. CONSTITUTION:The objective aluminate of stimulable phosphor is represented by the general formula: (Ce1-xTbx)(Mg1-a-bZnaMnb)Al2zO2.5+3z (wherein 0<x<=0.6, 0<a+b<1, and 4.5<=z<=15), and a fluorescent lamp containing a phosphor film comprising this phosphor on the inside surface of its glass bulb.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminate phosphor which emits green light by ultraviolet rays of low-pressure mercury discharge and a fluorescent lamp using the same.

[0002]

2. Description of the Related Art In recent years, a large color image display device that can be used outdoors has been developed and is becoming widespread. Planar emission type variable color fluorescent lamps used for pixels of such a large-sized display are disclosed in JP-A-61-55851 and JP-A-2-129847. These variable-color fluorescent lamps are composed of one or a plurality of groups of picture elements each of which emits a G (green), R (red), and B (blue) phosphor in a single color in order to form a pixel for a large-sized display. Has been done. Among these phosphors, as the G component phosphor, for example, terbium-activated cerium magnesium aluminate (hereinafter referred to as CAT) is used.

[0003]

As shown in FIG. 3, as a G component phosphor used in a conventional flat-emission fluorescent lamp for a large display, trivalent terbium represented by CAT is used. Since light emission is utilized, the color purity of green is not satisfactory, and there is a problem that the color reproduction range of a display device is narrower than that of a general color television, and improvement thereof has been desired. In FIG. 3, the R component phosphor is yttrium oxide activated with trivalent europium (referred to as YOX in FIG. 3), and the B component phosphor is barium magnesium aluminate activated with divalent europium (also referred to as YOX). BAM). 2 as a phosphor with good color purity for green emission
Light emission with divalent manganese is suitable. For fluorescent lamps, divalent manganese-activated zinc silicate, barium magnesium aluminate activated with divalent europium and divalent manganese, and divalent manganese. Activated cerium magnesium aluminate and divalent manganese and 3
Cerium magnesium aluminate activated with a valent terbium (Japanese Patent Publication No. 57-52390) is known. However, since the above-mentioned fluorescent lamp for a large-sized display is usually lit under a high load, the life of divalent manganese-activated zinc silicate and barium magnesium aluminate activated by divalent europium and divalent manganese is long. Inferior in brightness maintenance rate, and divalent manganese-activated cerium magnesium aluminate and 2
In the case of cerium magnesium aluminate activated with divalent manganese and trivalent terbium, the luminance retention rate during the life is good, but the luminance itself is low.

The present invention provides a green light emitting aluminate phosphor having good color purity and less deterioration in brightness throughout the life, and a fluorescent lamp using the same.

[0005]

In order to solve this problem, the aluminate phosphor of the present invention has the general formula: (Ce _{1- x}
Tb _x ) (Mg _1-ab Zn _a Mn _b ) Al _2z O _{2.5 + 3z} (where 0 <x ≦ 0.6, 0 <a + b <1, 4.5 ≦ z ≦ 1
5 is a number that satisfies the condition 5).

The fluorescent lamp of the present invention has the general formula:
(Ce _1-x Tb _x ) (Mg _1-ab Zn _a Mn _b ) Al _2z O
_{2.5 + 3z} (However, 0 <x ≦ 0.6, 0 <a + b <1,
It is a number that satisfies the condition of 4.5 ≦ z ≦ 15)).

[0007]

In the phosphor of the present invention, a part of divalent magnesium is replaced by zinc as shown in the above general formula, and therefore, improvement of divalent manganese emission and trivalent terbium emission is recognized, Conventional phosphor ((Ce, Tb) (M
g, Mn) Al ₁₁ O ₁₉ ).
In addition, when applied to a fluorescent lamp, the effect of the above replacement works well, and the characteristic that the luminance is less deteriorated throughout the life can be obtained.

Hereinafter, examples of the present invention will be described.

[0009]

EXAMPLE FIG. 1 shows a phosphor Ce _0.6 Tb _{0.4 according} to the present invention.
FIG. 6 shows the emission spectrum of Mg _0.68 Zn _0.30 Mn _0.02 Al ₁₁ O ₁₉ excited by 254 nm ultraviolet light in comparison with that of conventional Ce _0.6 Tb _0.4 Mg _0.98 Mn _0.02 Al ₁₁ O ₁₉ containing no Zn. In FIG. 1, curve 1 shows the emission spectrum of Ce _0.6 Tb _0.4 Mg _0.68 Zn _0.30 Mn _0.02 Al ₁₁ O ₁₉ and curve 2 shows Ce _0.6 Tb _0.4 Mg _0.98 Mn.
The emission spectra of _0.02 Al ₁₁ O ₁₉ are shown.

As is clear from FIG. 1, it was found that the phosphor according to the present invention remarkably improved the emission of divalent manganese near 517 nm and the emission of trivalent terbium near 543 nm.

Further, FIG. 2 shows Ce _0.6 Tb _0.4 Mg _0.68 Zn.
The chromaticity point P of the emission of the phosphor according to the present invention represented by _0.30 Mn _0.02 Al ₁₅ O ₂₅ when excited by 254 nm ultraviolet light is determined by the CAT, YOX, BAM used in the conventional flat-emission fluorescent lamp for a large-sized display. X, y with things
It is shown on the coordinates.

In FIG. 2, G, R, and B are chromaticity coordinates of the NTSC system used in a general color television.

The chromaticity point of emission of the phosphor according to the present invention is 2
It was confirmed that almost the same color purity was exhibited irrespective of the amount of Zn element that replaces part of the valency magnesium. That is, it can be seen from FIG. 2 that the color purity of the phosphor according to the present invention is good, and that color reproduction equivalent to that of a general color television is realized by combining the phosphor of the present invention with conventional YOX and BAM, for example. Recognize.

The aluminate phosphor according to the present invention can be obtained by the following manufacturing method.

The phosphor raw material is selected from at least one compound selected from cerium compounds such as cerium oxide and ceric nitrate as a cerium source, and terbium compounds such as terbium oxide and terbium fluoride as a terbium source. At least one compound, at least one compound selected from magnesium compounds such as basic magnesium carbonate and magnesium fluoride as a magnesium source, and at least one compound selected from zinc compounds such as zinc oxide and zinc carbonate as a zinc source. At least one,
At least one compound selected from manganese compounds such as manganese carbonate is used as a manganese source, and at least one compound selected from aluminum compounds such as aluminum oxide and aluminum hydroxide is used as an aluminum source. A predetermined amount of these raw materials are weighed and thoroughly mixed. The mixture is placed in a crucible and placed in air at 1200-
Bake at 1600 ° C. for 2-4 hours. After crushing the obtained fired product, it is put into the crucible again, and the temperature is 1400 in a reducing atmosphere.
Bake at ~ 1600 ° C for 2-4 hours. The fired product was crushed and washed with water to obtain a green light emitting aluminate phosphor of the present invention. In the method for producing a phosphor according to the present invention, it is appropriate to add a fluoride such as aluminum fluoride or magnesium fluoride, which is well known as a flux material used for an aluminate phosphor, or boric acid or boron oxide. The amount was effective in improving the brightness. On the other hand, the prototype evaluation using a fluorescent lamp is not generally the evaluation using a flat-emission fluorescent lamp for a large display.
It was decided to use a 0/28 lamp.

Specific examples of the present invention will be described below.
It Example 1 CeO₂ 0.60 mol Tb_FourO₇ 0.10 mol Mg (OH)₂ 0.68 mol ZnO 0.30 mol MnCO₃ 0.02 mol Al₂O₃ 5.50 moles Mix the above ingredients thoroughly and mix in air at 1300 ° C.
Bake for 3 hours. The resulting fired product is crushed and mixed, and then reduced
Baking at 1500 ° C for 4 hours in an atmosphere, crushing, washing with water,
A phosphor was obtained by mixing. The composition of the obtained phosphor is Ce.
_0.6Tb_0.4(Mg _0.68Zn_0.30Mn_0.02) Al₁₁O₁₉ 
Met. Apply this phosphor to the inner surface of the glass tube to
A 30/28 lamp was made. The brightness of this lamp is
Ce, which is a conventionally known phosphor fired as a comparison
_0.6Tb_0.4(Mg_0.98Mn_0.02) Al ₁₁O₁₉Using the same
It was 125% with respect to the luminance of the lamp thus manufactured.
In addition, the brightness maintenance rate after 2000 hours of lighting at the rated voltage
Regarding this, the lamp of Example 1 has 91.5%,
It was 87.5% in the lamp manufactured as a comparison. You
That is, the brightness of the lamp using the phosphor according to the present invention is
Both the brightness and the brightness retention ratio have clearly improved characteristics.
Was given. Example 2 Ce₂(NO₃)₃・ 6H₂O 0.30 mol Tb_FourO₇ 0.10 mol MgO 0.85 mol ZnCO₃ 0.05 mol MnCO₃ 0.10 mol Al₂O₃ 7.50 mol MgF2 0.015 mol A phosphor was obtained by the same treatment as in Example 1 using the above raw materials.
It was The composition of the obtained phosphor is Ce._0.6Tb_0.4(Mg_0.85
Zn_0.05Mn_0.10) Al₁₅O_{twenty five}Met.

This phosphor is applied to the inner surface of the glass tube and FC
An L30 / 28 fluorescent lamp was produced. The brightness of this lamp is the same as that of the baked Ce _0.6 Tb _0.4 (Mg _0.9 Mn).
The brightness was 110% with respect to the brightness of a lamp produced in the same manner using _0.10 ) Al ₁₅ O ₂₅ .

Further, regarding the luminance maintenance ratio after 2000 hours of lighting at the rated voltage, in the lamp of the second embodiment, 92.
5%, and 89.0% for the lamp manufactured for comparison.
Met. That is, in the lamp using the phosphor according to the present invention, the characteristics which are obviously improved in both the luminance and the luminance maintenance factor were obtained, and the effect of the present invention was recognized. Example 3 CeO ₂ 0.96 mol Tb ₄ O ₇ 0.01 mol Mg (OH) ₂ 0.75 mol ZnO 0.10 mol MnCO ₃ 0.15 mol Al ₂ O ₃ 6.00 mol H ₃ BO ₃₀ 0.003 mol A phosphor was obtained by the same treatment as in Example 1 using the above raw materials. The composition of the obtained phosphor is Ce _0.96 Tb _0.04 (Mg
_{It was 0.75} Zn _0.10 Mn _0.15 ) Al ₁₂ O _20.5 .

This phosphor is applied to the inner surface of the glass tube and FC
An L30 / 28 fluorescent lamp was produced. The brightness of this lamp is compared with the baked Ce _0.96 Tb _0.04 (Mg _0.85 M
was 115% with respect to the luminance of lamps prepared analogously using _{n 0. 15) Al 12 O 20.5} . Also, at rated voltage 2
Regarding the luminance maintenance ratio after lighting for 000 hours, this Example 3 is also used.
Lamp was 91.7%, and the lamp manufactured as a comparison was 88.5%. That is, in the lamp using the phosphor according to the present invention, the characteristics which are obviously improved in both the luminance and the luminance maintenance factor were obtained, and the effect of the present invention was recognized.

The effect of the phosphor of the present invention is recognized not only in the flat emission type fluorescent lamp for large-sized displays and the fluorescent lamp for general illumination but also in the fluorescent lamp field utilizing excitation in the vacuum ultraviolet region. It is what is done.

[0021]

As described above, in the aluminate phosphor and the fluorescent lamp of the present invention, a part of divalent magnesium is replaced with zinc, and therefore, divalent manganese emission and trivalent terbium emission are produced. A remarkable improvement is recognized, and a clear improvement in brightness is obtained as compared with the conventional phosphor. In addition, when applied to a fluorescent lamp, the effect of the above replacement works well, and the characteristic that the luminance is less deteriorated throughout the life can be obtained. Furthermore, by applying the phosphor according to the present invention to a flat-emission fluorescent lamp for a large-sized display or a fluorescent lamp that is turned on under a high load, it is possible to utilize green emission with good color purity.

[Brief description of drawings]

FIG. 1 is a diagram showing an emission spectrum of a phosphor as an example of the present invention in comparison with a conventional one.

FIG. 2 shows the chromaticity of the phosphor shown in Example 1 of the present invention as x,
y The diagram shown on the chromaticity diagram

FIG. 3 is a diagram showing chromaticity of B, G, and R of a flat-emission fluorescent lamp used for a conventional large-sized display on an x, y chromaticity diagram.

Claims (2)

[Claims] 1. A general formula: (Ce _1-x Tb _x ) (Mg _1-ab Z
n _a Mn _b ) Al _2z O _{2.5 + 3z} (where 0 <x ≦ 0.6,
0 <a + b <1, 4.5 ≦ z ≦ 15, which is a number satisfying the condition). 2. The general formula: (Ce _1-x Tb _x ) (Mg _1-ab Z
n _a Mn _b ) Al _2z O _{2.5 + 3z} (where 0 <x ≦ 0.6,
0 <a + b <1, 4.5 ≦ z ≦ 15, which is a number satisfying the condition), a fluorescent lamp comprising a phosphor film made of an aluminate phosphor.