JPH06248264A - Aluminate-based fluorescent substance - Google Patents

Abstract

PURPOSE:To obtain an aluminate-based fluorescent substance, composed of a specific composition, capable of producing a red or a reddish orange color, excellent in color rendering properties and useful as color TV, etc. CONSTITUTION:The fluorescent substance is composed of a composition of the formula {Re is rare earth element; [M] is one or more alkaline earth metals or zinc; (a) is 0.5-1.5; (b) is 5.5-7.0; (x) is 0.05-0.07} such as Y2O3.(Ba0.4Mg0.4)O.6 Al2O3:Eu0.2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminate type phosphor which emits red or reddish orange light.

[0002]

2. Description of the Related Art Yttrium europium oxide (Y-Eu) has been known as a red or red-orange emitting phosphor. This phosphor has a peak wavelength of 612 nm, has a very sharp emission spectrum, and is used as an excellent red component in a wide range of fields such as three-wavelength fluorescent lamps and color televisions.

[0003]

However, in the case of the fluorescent lamp, since the color rendering (Ra) has become more important as it is at present, the blue (450 nm) and green (54 nm)
3 nm), red (612 nm) and 490 n as an intermediate color
The color rendering is improved by cutting the transmission of the mercury emission line by adding a complementary color around m, or recently adding something that emits light in the deep red part (660 nm) (four wavelengths). There is.

However, in the case of Y-Eu, which is the main component of the red component, the waveform of 650 to 700 nm is weak and it is difficult to meet these needs.

Therefore, the present invention has been made in view of the above problems, and an aluminate-based aluminate having a luminescent property in which the color rendering of the conventionally used yttrium-europium oxide (Y-Eu) is improved. It is intended to provide a red or red-orange emitting phosphor.

[0006]

The aluminate-based phosphor described in claim 1 has the general formula: aRe ₂ O _3. [M] O.bAl ₂ O ₃ : Eu _x (where Re is a rare earth Element, [M] is an element selected from at least one or more kinds of alkaline earth metals and / or zinc, 0.5 ≦ a <1.5, 5.5 ≦ b <7.0, 0.05 ≦
x ≦ 0.7) which is a red or red-orange emitting phosphor.

The aluminate-based phosphor according to claim 2 is the aluminate-based phosphor according to claim 1, wherein M is barium (Ba), magnesium (Mg), or strontium. (Sr), calcium (C
The element is selected from at least one of a) and zinc (Zn).

Furthermore, the aluminate-based phosphor described in claim 3 is the aluminate-based phosphor according to claim 1 or 2, wherein Re is yttrium (Y),
The element is selected from at least one of gadolinium (Gd) and lanthanum (La).

[0009]

The aluminate-based phosphor of the present invention has a general formula: aRe ₂ O _3. [M] O.bAl ₂ O ₃ : Eu _x (where Re is a rare earth element and [M] is at least one kind). An element selected from at least one or more of alkaline earth metals and / or zinc, 0.5 ≦ a <1.5, 5.5 ≦ b <7.0, 0.05 ≦
x ≦ 0.7) which is a red or red-orange emitting phosphor.

In other words, Eu ³⁺ is formed into a crystal matrix of an aluminate by a rare earth (rare earth), and 680
This is an aluminate-based phosphor having a peak wavelength at ˜710 nm or a relatively high waveform.

That is, the composition of this phosphor is [M ₁ ] ³⁺
[M ₂ ] ₂ ⁺ · 6Al ₂ O ₃ ; based on Eu ³⁺ ,
In this case, [M ₁ ] ³⁺ is a trivalent metal and [M ₂ ] ²⁺ is a divalent metal. When determining the concentration range of each metal,
Experimentally, the possible range of "visible emission" is determined according to various conditions of the metal.

In addition, the concentration range is determined by an assumed crystal structure (for example, a type of beta-alumina structure). For example, as a prototype, 2 (Pb, M
n) In the form of O · 3Fe ₂ O ₃ , Pb ^{2+ is changed} to a trivalent metal, and Mg is added to Al ₂ O ₃ to ensure the total valence.

In the case of this crystal system, there are some restrictions. For example, [M ₂ ] ²⁺ (alkaline earth metal or zinc)
For, the number of atoms in the molecular formula is preferably 1 or less.
This is because if it exceeds 1, the luminous efficiency is considerably sacrificed. Therefore, the concentration range of each metal that provides visible light emission must be limited.

That is, the aRe ₂ O _3. [M] O.
In bAl ₂ O ₃ : Eu _x , 2 (Pb, Mn) O · 3F
Since e ₂ O ₃ (a type of magnetoplumbite / β-alumina structure) is used as a base,
In terms of composition, it is subject to the structural restrictions as described above. Furthermore, E
In order to obtain red-based light emission by u ³⁺ , trivalent, divalent,
The crystal structure of bAl ₂ O ₃ is preferable, but the characteristics peculiar to each metal influence the formation of the crystal.
The results were 5, 5.5 ≤ b <7.0 and 0.05 ≤ x ≤ 0.7.

As a raw material condition, in the case of a divalent metal, barium (Ba), calcium (Ca), strontium (S
An alkaline earth metal such as r) and zinc (Zn) are used. In addition, these divalent metals are salts that can easily become oxides, such as carbonates and oxalates. As described above, the number of atoms in the molecular formula is preferably 1 or less, and more preferably always 1. Further, preferable Re is yttrium (Y), gadolinium (Gd),
And an element selected from at least one kind of lanthanum (La).

As described above, the aluminate-based phosphor of the present invention has a higher emission in the deep red region than the emission spectrum of yttrium-europium oxide (Y-Eu) which is a conventional red phosphor. It has a different spectrum and is used as a new red component phosphor.

More specifically, the emission of yttrium europium oxide (Y-Eu), which is the same Eu ³⁺ -based red phosphor, as the host, is the main emission spectrum of the emission spectrum as described above.・ The peak is 612
nm, and at most 7 after the main peak
~ 8% small emission wavelength (sub-wave) is 58
It exists over 0 to 700 nm, but the number is about 10.

On the other hand, in the aluminate-based phosphor of the present invention, particularly yttrium, barium, magnesium,
710n when aluminum is the host of crystals
m became the peak wave.

As shown in each of the examples described below, when compared with yttrium-europium (Y-Eu), Y
-When the four Eu-580 nm sub-waves become the new base aluminate, they are converged to 590 nm and become a considerably large mountain, and after that, they can be divided into five large and small sub-waves.

The sub-peak at the position of 590 nm lowers the x value of the chromaticity of this phosphor and causes the reddish orange color tone. When barium and magnesium were used as the divalent metal in the matrix composition, their concentration ratios had no direct relation to the shifts of the respective emission waveforms and had no great influence, but Y ₂ O ₃ was used. YBE = Y ₂ O ₃ · (Ba ·
In the case of Mg) O · 6Al ₂ O ₃ : Eu ³⁺ , the Ba concentration is 90%.
The higher the level, the greater the light emission.

[0021]

EXAMPLES Example 1 (Preparation of Aluminate Phosphor 1) Raw materials having the compositions shown in the following Table 1 were thoroughly mixed by a blender mill and placed in an alumina tray, and the mixture was placed in the atmosphere at 1300 to 1500 ° C. Burned for hours. The composition of the obtained phosphor is Y ₂ O ₃
・ (Ba _0.4 Mg _0.4 ) O ・ 6Al ₂ O ₃ : Eu _0.2
(Hereinafter referred to as YBE).

[0022]

[Table 1]

FIG. 1 is a graph showing an emission spectrum of the obtained YBE phosphor. As shown in the figure, the peak position of the emission spectrum was at 710 nm and the sub peak was at 590 nm. In addition, Ip (strength of light emission) was 7.5% higher than that of the company.

Example 2 (Preparation of Aluminate Phosphor)
2) The raw materials having the compositions shown in Table 2 below were thoroughly mixed with a blender mill, placed in an alumina tray, and fired in the atmosphere at 1300 to 1500 ° C. for several hours. The composition of the obtained phosphor is Gd ₂ O.
₃・ (Ba _0.4 Mg _0.4 ) O ・ 6Al ₂ O ₃ : Eu _0.2
(Hereinafter referred to as GBE).

[0025]

[Table 2]

FIG. 2 is a graph showing the emission spectrum of the obtained GBE phosphor. As shown in the figure, the peak position of the emission spectrum is 616 nm and the sub-peak is 69
It was found to be at 0 nm. Incidentally, Ip increased by 44% with respect to the YBE standard.

Example 3 (Preparation of Aluminate Phosphor)
3) The raw materials having the compositions shown in Table 3 below were thoroughly mixed with a blender mill, placed in an alumina tray, and fired in the atmosphere at 1300 to 1500 ° C. for several hours. The composition of the obtained phosphor is La ₂ O.
₃・ (Ba _0.4 Mg _0.4 ) O ・ 6Al ₂ O ₃ : Eu _0.2
(Hereinafter referred to as LBE).

[0028]

[Table 3]

FIG. 3 is a graph showing an emission spectrum of the obtained LBE phosphor. As shown in the figure, the emission spectrum has a peak position of 619 nm and a sub-peak of 59.
The maximum wavelength is 700 nm. still,
In the case of La ₂ O ₃ , it has been found that 365 excitation rather than 254 excitation gives a stronger emission.

Example: 4 (wavelength of aluminate-based phosphor)
Characteristics) The obtained YBE, GBE, and LBE are converted to yttrium europium (Y-
Eu) was compared with the peak wavelength and the like. The following Table 4 is a table showing the results.

As shown in Table 4, when compared with yttrium-europium (Y-Eu), 58 of Y-Eu was obtained.
When 4 sub-waves of 0 to 600 nm become the new matrix aluminate, they are converged to 590 nm and become a considerably large mountain, and after that, they can be divided into 5 large and small sub-waves.

[0032]

[Table 4]

That is, the sub-position at this 590 nm position
It can be seen that the peak lowers the x value of the chromaticity of this phosphor and causes the reddish orange color tone.

The concentration ratio of divalent barium and magnesium in the matrix composition has no direct relation to the shift of each waveform and has no great influence, but YB using Y ₂ O ₃ is used.
In the case of E = Y ₂ O _3. (Ba.Mg) O.6Al ₂ O ₃ : Eu ³⁺ , the light emission increased at 90% Ba.

Example: 5 (Chromaticity of aluminate-based phosphor)
Characteristics) aRe ₂ O ₃ · (Ba _b , Mg _c ) O · dAl ₂ O ₃ :
Eu _x of Re ₂ O ₃ and _{La 2 O 3, Y 2 O} 3, Gd 2 O
Aluminate-based phosphors were produced by combining one or two as ₃ , and plotted on a chromaticity diagram (CIE). FIG. 4 is a chromaticity diagram of the obtained aluminate-based phosphor.

In the figure, YBE is Re ₂ O ₃ = Y ₂ O
₃ , GBE is Re ₂ O ₃ = Gd ₂ O ₃ , LBE is Re ₂
O ₃ = La ₂ O ₃ , YLB is Re ₂ O ₃ = (Y ₂ O ₃ ).
^{_{0.5 + (La 2 O 3)}} 0.5, YGB the Re ₂ O ₃ = (Y ₂
O ₃₎ shows a ^{_{0.3 + (Gd 2 O) 0.7}} .

As shown in the figure, when Gd is 100% or Gd is included, the x value tends to be high and the reddishness becomes strong.
Also, it can be seen that when La100% or La is included, the y value tends to be high, and the reddish orange color becomes strong.

Example: 6 (Emission of aluminate-based phosphor)
Characteristics 1) The emission characteristics of the obtained GBE phosphor according to the change in Gd ₂ O ₃ concentration were examined. In the GBE phosphor, the number of Gd ₂ O _{3 in} one molecule is 0.5, 0.75, 0.85, 0.90, 1.0.
0 was used, and the other composition conditions were the same.

FIG. 5 is a graph showing the emission spectrum of the GBE phosphor of each Gd ₂ O ₃ concentration, and Table 5 below summarizes the results of FIG. In addition, Table 5 in FIG.
The GBE phosphors having the respective Gd ₂ O ₃ concentrations shown in FIG. Further, Ip (emission intensity) in Table 5 is a relative value with 100 as the emission intensity of the best emission (the number of Gd ₂ O ₃ is 1.00) in the sample.

[0040]

[Table 5]

As can be seen from FIG. 5 and Table 5, Gd ₂ O ₃
The emission intensity increases as the concentration increases. However, the Gd ₂ O ₃ concentration limit is 1.00 at this composition ratio.
Is the limit, and it is known that the light emission is significantly reduced beyond that.

Example 7 (Emission of Aluminate Phosphor)
Characteristic 2) The emission characteristics of the obtained YBE phosphor according to the change of the Y ₂ O ₃ concentration were examined. As the YBE phosphor, the number of Y ₂ O _{3 in} one molecule was 0.5, 0.65, 0.75, 1.20, 1.50, and the other composition conditions were the same.

FIG. 6 is a graph showing the emission spectrum of the YBE phosphor of each Y ₂ O ₃ concentration, and the following Table 6 summarizes the results of FIG. 6 to 6 indicate YBE phosphors having the respective Y ₂ O ₃ concentrations shown in Table 6. Further, the Ip (emission intensity) in Table 6 is 100 for the emission intensity of the best emission (the number of Y ₂ O ₃ is 1.20) in the sample.
Is a relative value.

[0044]

[Table 6]

As can be seen from FIG. 6 and Table 6, it was confirmed that the emission intensity increased in accordance with the concentration with the highest Y ₂ O ₃ number of 1.20.

As described above, the aRe ₂ O ₃ ·.
[M] O.bAl ₂ O ₃ : Eu _x (where Re is a rare earth element, [M] is an element selected from at least one alkaline earth metal and / or zinc, and 0.5 ≦ a
<1.5, 5.5 ≤ b <7.0, 0.05 ≤ x ≤ 0.7) The aluminate-based phosphor has a higher emission in the deep red region than the conventional yttrium-europium (Y-Eu). It was shown to have corrugations.

Then, particularly in the case of yttrium aluminate, a luminescent phosphor having a peak at the position of 710 nm could be obtained. Further, it was possible to obtain a phosphor having a peak at 616 nm and a strong subpeak at 690 nm like gadolinium aluminate.

This can be provided as a new red component phosphor as a red-orange aluminate phosphor having a wavelength completely different from that of the conventional Y-En ³⁺ phosphor.

[0049]

As described above, the general formula of the present invention, aRe
₂ O ₃ · [M] O · bAl ₂ O ₃ : Eu _x (however, Re
Is a rare earth element, [M] is an element selected from at least one or more alkaline earth metals and / or zinc,
The aluminate-based phosphors represented by 0.5 ≦ a <1.5, 5.5 ≦ b <7.0, 0.05 ≦ x ≦ 0.7) emit light in the deep red region as compared with conventional yttrium-europium (Y-Eu). It has highly different waveforms and is useful as a new red component phosphor.

[Brief description of drawings]

FIG. 1 is a graph showing an emission spectrum of the obtained YBE phosphor.

FIG. 2 is a graph showing an emission spectrum of the obtained GBE phosphor.

FIG. 3 is a graph showing an emission spectrum of the obtained LBE phosphor.

FIG. 4 is a chromaticity diagram of the obtained aluminate-based phosphor.

FIG. 5 is a graph showing an emission spectrum of a GBE phosphor having various Gd ₂ O ₃ concentrations.

FIG. 6 is a graph showing an emission spectrum of a YBE phosphor of each Y ₂ O ₃ concentration.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Teruo Goto Inventor Teruo Goto 2-2-1 Shimotsuruma, Yamato-shi, Kanagawa Inside the Tokyo Chemical Research Institute, Inc.

Claims (3)

[Claims] 1. A general formula: aRe ₂ O _3. [M] O.bAl ₂ O ₃ : Eu _x (where Re is a rare earth element, and [M] is at least one alkaline earth metal or / and zinc. Element selected from at least one or more, 0.5 ≦ a <1.5, 5.5 ≦ b <7.0, 0.05 ≦
x ≦ 0.7), and an aluminate-based phosphor. 2. The M is an element selected from at least one of barium (Ba), magnesium (Mg), strontium (Sr), calcium (Ca), and zinc (Zn). The aluminate-based phosphor according to claim 1. 3. The aluminum according to claim 1, wherein the Re is an element selected from at least one of yttrium (Y), gadolinium (Gd), and lanthanum (La). Acid salt phosphor.