JP2753138B2 - Aluminate phosphor and fluorescent lamp using the same - Google Patents

Description

Description: 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.

2. Description of the Related Art In recent years, a large-sized color video display device that can be used outdoors has been developed, and its use has been spreading. Japanese Patent Laid-Open Nos. 61-55851 and 2-129 disclose a flat emission type variable color fluorescent lamp used for pixels of such a large display.
No. 847 discloses this. These variable color fluorescent lamps are G (green), R
It is composed of one or a plurality of sets of picture elements that cause the phosphors emitting red (red) and B (blue) to emit monochromatic light, respectively. Among the phosphors used in such a flat display fluorescent lamp for a large display, a terbium-activated cerium magnesium aluminate (hereinafter abbreviated as CAT) is used as the G component phosphor.

Problems to be Solved by the Invention As shown in FIG. 3, as a G component phosphor used in a conventional flat emission fluorescent lamp for a large display, light emission by trivalent terbium as represented by CAT is used. However, there is a problem that the color purity of green is not satisfactory and the color reproduction range as a display device is narrower than that of a general color television, and improvement thereof has been desired. In the figure, the R component phosphor is yttrium oxide (hereinafter, referred to as “trivalent europium”).
The B component phosphor is a barium magnesium aluminate activated with divalent europium (hereinafter referred to as BA).
M).

Divalent manganese luminescence is suitable as a phosphor having good color purity of green luminescence, and for fluorescent lamps,
Divalent manganese-activated zinc silicate, barium magnesium aluminate activated with divalent europium and manganese, and cerium magnesium aluminate activated with divalent manganese are known. Since the fluorescent lamps for large displays are usually lit at high load,
In the case of barium magnesium aluminate activated with divalent manganese-activated zinc silicate and divalent europium and manganese, the luminance retention rate during the lifetime is inferior, and cerium activated with divalent manganese In the case of magnesium aluminate, the luminance retention rate during the lifetime is good,
There is a disadvantage that the luminance itself is low.

SUMMARY OF THE INVENTION The present invention provides an aluminate phosphor which is used in a fluorescent lamp to be lighted under high load conditions such as for a large display and has good color purity and a small decrease in luminance throughout its life, and a fluorescent lamp using the same. Is what you do.

Means for Solving the Problems In order to solve such a problem, an aluminate phosphor of the present invention has a general formula: Ce (Mg, Eu, Mn) Al _2z O _{2.5 + 3z} (where 4.5 ≦ z ≦ 15)
It is represented by

Further, the fluorescent lamp of the present invention has a general formula: Ce (Mg, Eu, Mn) Al _2z O _{2.5 + 3z} (where 4.5 ≦ z ≦ 15)
A fluorescent film made of an aluminate phosphor represented by the following formula is provided on the inner surface of the glass tube.

Action Since the aluminate phosphor of the present invention uses two kinds of co-activators of divalent europium and trivalent cerium, its sensitizing effect is remarkably recognized, and the conventional trivalent cerium alone is used. A clear improvement in brightness is obtained as compared with the case of co-activation. In addition, when applied to a fluorescent lamp, the above-described sensitizing effect works well, and a characteristic with a small decrease in luminance throughout the life can be obtained.

 Hereinafter, examples of the present invention will be described.

Embodiment FIG. 1 shows an aluminate phosphor CeMg _{0.79 according to the} present invention.
The emission spectrum (curve 1) of Eu _0.01 Mn _0.2 Al ₁₁ O ₁₉ excited by 254 nm ultraviolet light was compared with the conventional Eu-free CeMg _0.8 Mn _0.2 Al
_This is shown in comparison with that of ₁₁ O ₁₉ (curve 2).
As is clear from FIG. 1, the phosphor according to the present invention
It was found that light emission by trivalent cerium existing near 360 nm was reduced, and light emission by divalent europium was newly obtained near 450 nm. That is, by using two types of conventional coactivators, which are obtained by adding divalent europium to trivalent cerium, emission of divalent manganese can be enhanced and emission of divalent europium can be obtained. Above all, the effects of the present invention are exhibited.

FIG. 2 shows the general formula: CeMg _0.8-x Eu _x Mn _0.2 Al ₁₅ O ₂₅
The chromaticity point of emission of 254 nm ultraviolet excitation of a series of phosphors according to the present invention represented by CAT, YOX, and BAM used in conventional flat emission fluorescent lamps for large displays, x, y It is shown on the coordinates. In FIG. 2, G, R, and B are N used in a general color television.
These are chromaticity coordinates of the TSC system. From FIG. 2, it can be seen that the color purity of the phosphor according to the present invention is good, and the conventional phosphors such as YOX and B
It can be seen that color reproduction equivalent to that of a general color television is realized by combining with AM.

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

The raw material of the phosphor is at least one kind of a mixture selected from cerium compounds such as cerium oxide and cerous nitrate as a cerium source, and the magnesium source is selected from magnesium compounds such as basic magnesium carbonate and magnesium fluoride. At least one compound selected from among europium compounds such as europium oxide and europium fluoride as a europium source, and at least one compound selected from manganese compounds such as manganese carbonate as a manganese source. ,
As the aluminum source, at least one compound selected from aluminum compounds such as aluminum oxide and aluminum hydroxide is used. A predetermined amount of these raw materials is weighed and mixed well. The mixture is placed in a crucible and calcined in air at 1200 to 1600 ° C. for 2 to 4 hours.

After the obtained fired product is pulverized, it is put again in a crucible and fired at 1400 to 1600 ° C. for 2 to 4 hours in a reducing atmosphere. The fired product was subjected to a treatment such as crushing and washing 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 described above,
Addition of fluorides such as aluminum fluoride and magnesium fluoride, or boric acid and boron oxide, which are well-known as flux materials used for aluminate phosphors, is effective in improving the luminance if an appropriate amount is used. Obtained.

 Next, examples of the present invention will be described.

Example 1 CeO ₂ 1.00 mol Mg (OH) ₂ 0.79 mol Eu ₂ O ₃ 0.005 mol MuCO ₃ 0.20 mol Al ₂ O ₃ 5.50 mol The above raw materials are sufficiently mixed and fired at 1400 ° C. for 3 hours in the air. After crushing and mixing the obtained baked product, the mixture is baked at 1600 ° C. for 4 hours in a reducing atmosphere,
After washing with water and mixing, a phosphor was obtained.

The composition of the obtained phosphor was Ce (Mg _0.79 Eu _0.01 Mn _0.2 ) Al
₁₁ O ₁₉ This phosphor was applied to the inner surface of a glass bulb to produce an FCL30 / 28 fluorescent lamp. The luminance of this fluorescent lamp was 130% with respect to the luminance of a fluorescent lamp similarly manufactured using Ce (Mg _0.8 Mn _0.2 ) Al ₁₁ O ₁₉ which is a conventionally known phosphor fired for comparison. Was. Further, the luminance maintenance ratio after lighting for 2000 hours at the rated voltage was 90.5% for the fluorescent lamp of this example and 87.0% for the fluorescent lamp manufactured as a comparison. That is, in the fluorescent lamp using the phosphor according to the present invention, characteristics that are clearly improved in both luminance and luminance maintenance ratio were obtained.

Example _{2 Ce 2 (NO 3) 3} · 6H 2 O 0.50 mol MgO 0.88 mol Eu ₂ O ₃ 0.0025 moles MnCO ₃ 0.10 moles Al ₂ O ₃ 7.50 mole MgF ₂ 0.015 moles the raw material processing as in Example 1 using To obtain a phosphor. The composition of the obtained phosphor was Ce (Mg _0.895 Eu _0.005 Mn _0.10 ) Al ₁₅ O ₂₅ .

This phosphor was applied to the inner surface of a glass bulb to produce an FCL30 / 28 fluorescent lamp. The luminance of this fluorescent lamp was 120% as compared with the luminance of a fluorescent lamp similarly produced using Ce (Mg _0.9 Mn _0.1 ) Al ₁₅ O ₂₅ calcined for comparison. Further, the luminance maintenance ratio after lighting for 2000 hours at the rated voltage was 92.0% for the fluorescent lamp of this example and 89.0% for the lamp manufactured as a comparison.

That is, in the lamp using the phosphor according to the present invention, characteristics that were clearly improved in both luminance and luminance maintenance ratio were obtained, and the effect of the present invention was recognized.

Example 3 CeO ₂ 1.00 mol Mg (OH) ₂ 0.80 mol Eu ₂ O ₃ 0.025 mol MnCO ₃ 0.15 mol Al ₂ O ₃ 6.00 mol H ₃ BO ₃ 0.003 mol Phosphor by the same treatment as in Example 1 using the above raw materials I got The composition of the obtained phosphor was Ce (Mg _0.8 Eu _0.05 Mn _0.15 ) Al ₁₂ O _20.5 . This phosphor was applied to the inner surface of a glass bulb to produce an FCL30 / 28 fluorescent lamp. The brightness of this fluorescent lamp was 117% of the brightness of a fluorescent lamp similarly manufactured using Ce (Mg _0.85 Mn _0.15 ) Al ₁₂ O _20.5 fired for comparison. Further, the luminance maintenance ratio after lighting for 2000 hours at the rated voltage was 91.0% for the fluorescent lamp of the present example and 89.0% for the fluorescent lamp manufactured as a comparison.

That is, in the lamp using the phosphor according to the present invention, characteristics that were clearly improved in both luminance and luminance maintenance ratio were obtained, and the effect of the present invention was recognized.

Example 4 Ce ₂ (CO ₃ ) ₃ .6H ₂ O 0.50 mol Mg (OH) ₂ 0.40 mol Eu ₂ O ₃ 0.10 mol MnCO ₃ 0.40 mol Al (OH) ₃ 20.00 mol Same as Example 1 using the above raw materials. A phosphor was obtained by the treatment. The composition of the obtained phosphor was Ce (Mg _0.4 Eu _0.2 Mn _0.4 ) A
l ₂₀ O _32.5 . This phosphor was applied to the inner surface of a glass pulver to produce an FCL30 / 28 fluorescent lamp. The brightness of this fluorescent lamp was determined by comparing the calcined Ce (Mg _0.4 Mn _0.4 ) Al ₂₀ O
110 for the brightness of a lamp similarly made using _32.5
%Met. Further, the luminance maintenance ratio after lighting for 2000 hours at the rated voltage was 89.0% for the fluorescent lamp of the present example and 85.0% for the fluorescent lamp manufactured as a comparison.

That is, in the fluorescent lamp using the phosphor according to the present invention, characteristics that are clearly improved in both luminance and luminance maintenance ratio are obtained, and the effect of the present invention is recognized.

The aluminate phosphor according to the present invention is applicable not only to the flat emission fluorescent lamp for the large-sized display and the fluorescent lamp for general lighting that is operated under a high load, but also to a fluorescent lamp utilizing excitation in a vacuum ultraviolet region. The effect is also recognized in the field.

Effect of the Invention As described above, according to the present invention, the conventional co-activation of only trivalent cerium can be achieved by simultaneously using two types of co-activators, divalent europium and trivalent cerium. Thus, a green-emitting phosphor made of divalent manganese, which cannot be obtained and has a high luminance and a good luminance maintenance rate throughout its life, can be obtained. Further, when the phosphor according to the present invention is applied to a flat light emitting fluorescent lamp for a large display or a fluorescent lamp which is lighted with a high load, green light emission with good color purity can be utilized.

[Brief description of the drawings]

FIG. 1 is a diagram showing the emission spectrum of the aluminate phosphor according to the present invention in comparison with the conventional one, and FIG. 2 is a graph showing the chromaticity of the phosphor of Example 1 of the present invention in x, y chromaticity. FIG. 3 shows the chromaticity of B, G, and R of the conventional flat light emitting fluorescent lamp used for a large-sized display on the x, y chromaticity diagram.

Claims (2)

(57) [Claims] 1. The general formula: Ce (Mg, Eu, Mn) Al _2z O _{2.5 + 3z} (where 4.5 ≦ z ≦ 15)
An aluminate phosphor represented by the formula: 2. General formula: Ce (Mg, Eu, Mn) Al _2z O _{2.5 + 3z} (where 4.5 ≦ z ≦ 15)
A fluorescent lamp comprising a fluorescent film made of an aluminate phosphor represented by the formula (1) on the inner surface of a glass tube.