JPS59102979A - Fluorescent material - Google Patents

Abstract

PURPOSE:To provide a fluorescent material having a specific composition, applicable stably to a fluorescent lamp and giving a lamp having improved luminance, by substituting a part of aluminum in an Eu<++>-doped alkaline earth metal aluminate fluorescent material with boron, gallium, etc. CONSTITUTION:The objective fluorescent material has the chemical composition of formula [Me is an element selected from B, Ga, Y, and La; 0.005<=x<=0.15; 0<y<=0.1 (preferably 0.001<=y<=0.01); 0.5<=m<=2.0 (preferably 1.0<=m<=1.5); 4<= n<=6 (preferably 4.5<=n<=5.5)] corresponding to the structure obtained by substituting a part of Al of an Eu<++>-doped alkaline earth metal aluminate fluorescent material with an element selected from B, Ga, Y and La.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention describes the use of divalent europium-activated alkaline earth metal aluminate phosphors in which a portion of the aluminum is selected from the group of boron, gallium, yttrium and lanthanum. This relates to a phosphor substituted with at least one selected element.

Structure of conventional examples and their problems Conventionally, as an aluminate phosphor that emits light in the blue-green wavelength range when excited with ultraviolet rays or cathode rays, Japanese Patent Publication No. 62
As shown in Publication No. 22836, strontium magnesium activated with divalent europium
Aluminate phosphors are known. However, these divalent europium-activated strontium magnesium aluminate phosphors are described in Reference 1. M,
P, LVerstegen, D@Radielov
ic and L@E@Vrenben.

J, Electrochem, Soc, 121 (1
2), 1627N631 (1974), it is extremely unstable when applied to fluorescent lamps, and a significant drop in luminous output that occurs during the lamp life is unavoidable, so it cannot be put to practical use. It was unsuitable for serving.

Inventors d: As a phosphor that can overcome these drawbacks of phosphors, we have proposed a strontium-magnesium-aluminate phosphor activated with divalent europium, whose chemical composition is (Sr2- xEuXo2)・mMgO11nA1203
In the formula, x, m and n are each 0.01≦
We have previously proposed a phosphor that satisfies the following: X≦0.30, 0.5≦m≦2.0, 4≦n≦6. .

Although this phosphor overcomes the conventional disadvantage of instability when applied to fluorescent lamps and exhibits excellent 74 luminous output maintenance characteristics, the luminous output was not fully satisfactory. .

OBJECTS OF THE INVENTION The present invention provides a phosphor which is stable when applied to a fluorescent lamp and which provides an improved luminous output compared to previously proposed phosphors.

Components of the Invention The inventors continued to conduct experimental research on such phosphors, and found that a portion of the aluminum in the host crystal of the phosphor was replaced by at least one member selected from the group of boron, gallium, yttrium, and lanthanum. It has been found that by substituting elements, it is possible to significantly improve the emission output by excitation of 2 54 nm ultraviolet light emitted from a fluorescent lamp without significantly changing the emission spectrum.

That is, the present invention is characterized in that a part of the aluminum of the rontium magnesium aluminate phosphor activated with divalent europium is replaced with at least one element selected from the group of boron, gallium, yttrium, and lanthanum. The chemical composition is 2(Sr1-ycEuxO)・mMqOIIn(A12
□MeyO3), where Me represents at least one element selected from the group of boron, gallium, yttrium and lanthanum, and x, y, m and n are each.

0.006≦X≦Q, 16 0〈y≦0.1 0.5≦m<2.0 4≦m<6 It is characterized by a phosphor within the range of .

In the phosphor of the present invention having a composition represented by formula 1, the content y of at least one element selected from the group of boron, gallium, yttrium, and lanthanum is approximately 0, although it varies slightly depending on the type of each element. A range of .001 to 0.01 is particularly preferred. It is important that the value of y does not exceed 0.1; if it exceeds this value, the luminous output will decrease, and when applied to a fluorescent lamp, the maintenance characteristics of the luminous output will also decrease. However, the effects of this invention cannot be obtained.

The phosphor of the present invention is a strontium-magnesium-aluminate phosphor activated with essentially divalent europium that satisfies the composition range shown in the chemical composition. Any phosphor that is substituted with at least one element selected from the group of yttrium and lanthanum may be used.If part of strontium is replaced with barium, calcium, etc. as is commonly done, the substitution If the amount is small, the same effects as those of the phosphor according to the present invention can be obtained.

The reason for limiting the ranges of m and n above will be described below.

When m takes a value of 2 or more, for example, the emission peak wavelength is 500 nm to 52 nm due to ultraviolet excitation at 254 nm.
It shows efficient light emission in the green region near Onm, but
When the application to fluorescent lamps was studied, it was found that significant deterioration occurred during the firing process for removing the binder in the phosphor coating process in the normal lamp manufacturing process.

Furthermore, when m is less than 0.5, the luminous efficiency decreases, making it unsuitable for practical use.

On the other hand, when n takes a value of 6 or more, the emission peak wavelength is from 463 nm to 463 nm when excited with ultraviolet light at 254 nm, for example, as in the conventional strontium magnesium aluminate phosphor activated with divalent europium. 475n
Although it is possible to obtain a lamp that emits light efficiently in the blue-green region of When applied, it was confirmed that there was significant deterioration during the baking process and throughout the service life. Also, n is 4
If it is less than 20%, a stable phosphor cannot be obtained, and the luminous efficiency decreases, making it impossible to obtain a phosphor that can be put to practical use. In the above range, m is particularly 1. ○〜1.5
When n is 4.5 to 5.5, efficient light emission with an emission peak wavelength in the blue-green region of approximately 480 nm to 490 nm can be obtained, and it is stable even when applied to a fluorescent lamp. It is especially good because of this.

Second, regarding the europium content This is due to the fact that even though a large amount of expensive europium is used, effective light emitting output cannot be obtained and it cannot be put to practical use.

In order to obtain the phosphor of the present invention, a compound containing the constituent elements in the preceding formula, such as SrCO3,3MqCo3.Mg (O
H) 2 fist 3H20tA 1203. Eu2o3. H3
BO3 and borates, carbonates, oxides, etc. of gallium, yttrium, and lanthanum are mixed to have the composition shown in the above formula, and this mixture is placed in a heat-resistant container such as a quartz boat and heated in a mixed air flow of nitrogen and hydrogen. What is necessary is just to bake at the temperature of 1000 degreeC - 1300 degreeC for the desired time in the reducing atmosphere like the inside.

As is clear from the examples shown below, the phosphor of the present invention can also be excited by ultraviolet rays or cathode rays and exhibits blue-green luminescence with high luminous efficiency. It is suitable as a phosphor for use.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Example 1 SrCO3 1.86 mol 3MqCO3・Mq(OH)2 ・3H200,175
A mixture with a composition of 4.896 moles of Al2O34.896 moles of H3BO30.05 moles of Eu2O30.075 moles of AlF3.3H200.40 moles was placed in a quartz boat and heated at a temperature of 1250°C in a mixed gas stream with a nitrogen:hydrogen volume ratio of 10=1. It was baked for 2 hours. The fired product was cooled in an air stream having the same composition, and then crushed and sieved. The obtained product emitted blue-green light when excited by ultraviolet rays or cathode rays, and could be used as a phosphor.

When this phosphor was analyzed, it was found to be expressed by the following formula 2 (%), and the luminous output upon excitation of ultraviolet light at 254 nm was that of the phosphor 2 (Sro, 92.Euo, .7), which does not contain boron. .○)・0.7Mg0
．． It was improved by about 161) compared to 6A1203.

Example 2 SrCO3 1.92 mol MgQ 0.6 mol Mgp 2 0.5 mol A
l2O38,664 mol G3203 0.47 mol H
A phosphor was obtained in the same manner as in Example 1 using a mixture having a composition of 30,376 mol of 3BO3 and 0.04 mol of Fu203. When the obtained phosphor was analyzed, it was found to be expressed by the following formula: 40) ・1, I M
It was improved by about 7 coefficients compared to gO-4,7A1203.

Examples 3 to 5 The boron portion in the raw material composition of Example 1 was replaced with 30,025 mol of Ga2O (Example 3) Y2O
20,025 mol (Example 4) La203
A phosphor was obtained using a mixture having a composition substituted with 0.025 mol (Example 5) and by the same firing method as in Example 1 above. When these were analyzed, they were found to be fluorophores represented by the following formulas.

2(SrO,925EuO,0760) -0,7M(
J・O, 5 (A11.99GaO, 0103) 2 (S r o , 92s E u o , 076
0) ”O-7MCJ'O-5(”'1.99Y0
．． 0103) 2 (S ro , 925 E uo , oy60
) ”O-7Mq”O-6(A11.99”ao, 0
103) The output power generated by excitation of these phosphors with 254 nm ultraviolet light (is 2(Sro, 92.Euo, .7.O)・0.7
109 respectively compared to those of Mgo/6A1203
%.

There was a clear improvement of 106% and 104%.

Next, in this invention, by changing the types of gallium, boron, yttrium, and lanthanum mentioned above, and by changing the value of y variously as shown in the table below, the chemical composition is expressed by the following formula (% formula %). I got a body. 254 of each of these phosphors
The results of measuring the luminescence output by nm ultraviolet excitation are shown in the same table.

As is clear from the above table below, the light emission output is improved even when the value of y is as small as about 0.0005. Also,
As mentioned above, the value of this y is ○, O○1~0.01
It is also clear that the range is particularly preferred.

In addition, in this invention, the above-mentioned gallium and boron.

As an example of yttrium and lanthanum was shown in Example 2, it was confirmed that a similar improvement in light emission output could be obtained even when two or more types were used.

Further, the emission spectrum of the phosphor of Example 1 is shown in FIG. 1, which is an emission spectrum that is almost representative of all the phosphors of the present invention.

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention utilizes a divalent europium-activated alkaline earth metal aluminate phosphor in which a portion of the aluminum is combined with boron and gallium.

It is substituted with at least one element selected from the group of yttrium and lanthanum, and its chemical composition is 2 (S r 1.-xEu xO) -mug○"
n (Al1-yMe y○3), where Me represents at least one element selected from the group of boron, gallium, yttrium and lanthanum, and X, 7
．． By setting m and n within the ranges of 0.005≦X≦0.15 0<y≦0.1 0.5≦m<2.0 4≦n<6, conventional divalent europium It is possible to provide a phosphor that is not only more stable when applied to a fluorescent lamp than a J-activated aluminate phosphor, but also can significantly improve its luminous output.

[Brief explanation of drawings]

Figure it:j: A diagram showing an example of the emission spectrum of the phosphor of the present invention.

Claims (1)

[Claims] Part of the aluminum in the alkaline earth metal aluminate phosphor activated with divalent europium is replaced with at least one element selected from the group of boron, gallium, yttrium, and lanthanum. The chemical composition is 2(Sr1-xEuxO) -mMq○・n(A12.
,,yMeA03) in which Me represents at least one element selected from the group of boron, gallium, yttrium, and lanthanum, and x, y, m, and n
A phosphor characterized in that the values are within the following ranges: 0, 06≦X≦0.15, 0<y≦0.1, 0.6≦m<2.0, 4≦n<6.