JPS62578A - Phosphor - Google Patents

Abstract

PURPOSE:To obtain a phosphor exhibiting an intensity of luminescence stronger than a conventional blue phosphor comprising an alkaline earth metal aluminate activated with a divalent europium, by dissolving silicon in the conventional blue phosphor comprising an alkaline earth metal aluminate. CONSTITUTION:A phosphor comprising an alkaline earth metal silicoaluminate activated with a divalent europium. The chemical compsn. is represented by the formula (wherein M is at least one alkaline earth metal selected from Sr and Ca; 0.005<=a<=1.5; 0<=b<=0.5; 0<x<=8; 10<=y<=50; and 0<z<=3.5). The phosphor can be obtained by mixing oxides or various compds. capable of being converted into oxides of the constituent elements at predetermined proportions and repeatedly calcining the mixture in a weak reducing gas stream.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to phosphors, and more particularly to divalent europium activated alkaline earth metal silicate blue phosphors.

2. Prior Art Conventionally, aluminate phosphors activated with divalent europium have been produced using alkaline earth metal aluminate compounds with a hexagonal β crystal shape, as shown in Japanese Patent Publication No. 52-22836.
- When made into a crystal with an alumina structure, it can be made into a practical blue phosphor.

Problems to be Solved by the Invention Such conventional blue phosphors are used as blue phosphors in fluorescent lamps, particularly in three-wavelength fluorescent lamps. In order to achieve this goal, it has been desired to provide a blue phosphor with even higher luminescence intensity.

The present invention was made in response to such demands, and is a three-wavelength fluorescent lamp that uses a divalent europium-activated alkaline earth metal aluminate blue phosphor and has higher efficiency than a three-wavelength fluorescent lamp. This makes it possible to obtain a wavelength range emitting type fluorescent lamp, and the purpose is to provide a blue fluorescent material with high emission intensity.

Means for Solving the Problem In order to solve this problem, the inventors investigated the conventional aluminate blue phosphor and made silicon a solid solution in the alkaline earth metal aluminate compound. As a result, we have discovered a phosphor that has higher luminescence intensity than conventional divalent europium-activated alkaline earth metal aluminate phosphors. That is, the phosphor of the present invention has the general formula: (Ba3-a-bEuaMb)O3-xMqo
-yA1203- r, S to2 (°, however, M represents an alkaline earth metal consisting of at least one element among Sr and Ca), &, b, X, 7
and 2 are in the range of o, oos≦a≦1.6, 0≦b≦O, S O (x≦8, 10≦y≦50 O (z≦3.6), respectively.

Function: With this configuration, it is possible to obtain an excellent blue phosphor having a higher emission intensity than the conventional divalent europium-activated alkaline earth metal aluminate blue phosphor.

Luminate has high utility value as it emits blue light with high color purity. However, when used as a blue phosphor in a three-wavelength fluorescent lamp, satisfactory color rendering properties can be obtained, but the luminous flux is low, making this type of three-wavelength fluorescent lamp highly efficient. The development of a blue phosphor was desired.

Therefore, we focused on a divalent europium-activated alkaline earth metal aluminate blue phosphor, which has a spectral distribution suitable as a blue phosphor for a three-wavelength fluorescent lamp, and developed it without changing its spectral distribution. We investigated increasing the luminescence intensity. As a result, they discovered that the luminescence intensity could be increased by dissolving silicon in a conventional alkaline earth metal aluminate blue phosphor.

In the phosphor of the present invention, I indicates the MqO composition ratio, O (x≦8゛, and y indicates the Al2O3 composition ratio, 10≦y≦60.

The y's influence each other, so if I is made smaller, it is better to make y smaller, and if I is made larger, y
The luminescence intensity can be increased by making the value larger.

However, there is a limit to the range, and it is not possible to obtain a phosphor with high luminous intensity in the range where I is O (X≦8, y is less than 10, and y exceeds 50.
is in the range of 10≦y≦50 and when X is 0 or exceeds 8, high emission intensity cannot be obtained. a indicates the concentration of europium, which is an activator, and is 0,00
5≦a≦1.6. If a is less than 0.005, sufficient luminescence intensity cannot be obtained, and even if a exceeds 1.6, sufficient luminescence intensity cannot be obtained due to concentration quenching. b represents the atomic ratio of at least one of Sr and Ca, and in the range of 0≦b≦0.5, b=o
It is possible to obtain characteristics equivalent to those in . 2 is 8
102 composition ratio, 0 (2≦3.5.2
As the value of 2 increases to around 0.4, the emission intensity increases, and even if 2 is increased beyond that, the emission intensity cannot be increased. When the value exceeds 3.5, the emission intensity becomes lower than that when 2=0.

The phosphor of the present invention can be obtained by the following method. A predetermined amount of oxides or various compounds that can be turned into oxides by thermal decomposition, which are the constituent elements of the phosphor of the present invention, are weighed out, mixed in a ball mill, etc., and placed in a crucible.
H2=10:10 in a slightly reducing gas flow, 110
Bake at a temperature of 0 to 1600°C for 1 to 5 hours. After firing,
The fired product cooled in the same gas is crushed and sieved, and then fired again under the same conditions. In this case, it is better to use the weakly reducing gas through water. After repeating this firing several times, the resulting fluorescent material emits blue light when excited by ultraviolet rays, X-rays, or electron beams. In addition, when weighing raw materials, it is desirable to use a halide, a boron-based compound, or a phosphorus-based compound as a flux.

Hereinafter, specific examples of the present invention will be described.

Example 1 Composition formula (Ba2,8Eu0.2)O3・4Mqoe11
Fluorophores were prepared in which 2 was changed in 5Aj203.zsi%.

The preparation was carried out by the method described above, and the phosphor obtained was 254
The emission characteristics of nm ultraviolet light were investigated. In the blue phosphor of the present invention, even when the value 2 was changed, the spectral distribution did not change, and the maximum emission wavelength remained constant at 451 nm.

The emission intensity is the peak height at the maximum emission wavelength, 2
Figure 1 shows the changes in .

That is, Asahi S x0 is added to the conventional aluminate blue phosphor.
By adding 2, it is possible to significantly improve the peak height compared to that without adding SiO3.

Note that chemical analysis of the obtained phosphor does not change the composition at the time of weighing. For example, chemical analysis of the phosphor at z=0.5 in Figure 1 reveals (Ba2.8Eu0.2)o
3.4. lMgO・16.1Aj203・o, 48Si
It was O2. The spectral distribution diagram of this phosphor is shown in FIG. It's not a thing.

Example 2 Composition formula (Ba2.8Euo, 2)Q3・0.01Mgo
- A phosphor was prepared to have 12A1203.0.5Sio2. The preparation method is the same as in Example 1. The relative peak height of the resulting phosphor was 110% of that without S102.

Example 3 Composition formula (Ba2.8Eu, 2)O3-8Mg0-rs
The phosphor was prepared to have oAt203-1.0 S102. The preparation method is the same as in Example 1. The relative peak height of the resulting phosphor was 108 cm compared to that without added SiO□.

Example 4 Composition formula (Ba1., Eu1.6)O3.3Mg0-1
A phosphor was prepared to be 6AA203-1, OSiO3. The preparation method is the same as in Example 1. The relative peak height of the resulting phosphor was 113 cm compared to that without added 5lo2.

Example 5 Composition formula (Ba2.8Euo, 2)O3.3Mqo.16
A phosphor was prepared to be A12o3.0.5 SiO3. The preparation method is the same as in Example 1. The relative peak height of the resulting phosphor was 114 cm compared to that without added SiO2.

Example 6 Composition formula (Ba2.6Eu0.2Sr, 2)O3-3M (
A phosphor was prepared as JO-1eAt203@0-5S102. The preparation method is the same as in Example 1. The relative peak height of the resulting phosphor was 114 cm compared to that without added Sio2.

Example 7 Composition formula (Ba2.6Eu0.2Ca0.2) o3 conflict 3M
A phosphor was prepared to have qO.16A12o3.0,5S102. The preparation method is the same as in Example 1. The relative peak height of the resulting phosphor was 114% of that without added Si02.

Example 8 Compositional formula (B &2.4Euo, 2Cao, 2Sr
o, 2) O3” 3M qo.

A phosphor was prepared to be 1e At 203.0.5 SiO3. The preparation method is the same as in Example 1. The relative peak height of the resulting phosphor was 113 cm relative to that without added S102.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, when excited with 254 nm ultraviolet rays, the light emission intensity is improved compared to the conventional divalent europium-activated alkaline earth metal aluminate phosphor. can get.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relative peak height when the solid solution amount of S102 is changed in the phosphor of the present invention, and Figure 2 is a diagram showing the relative peak height when the solid solution amount of S102 is changed in the phosphor of the present invention. It is a spectral distribution diagram when excited.

Claims (1)

[Claims] An alkaline earth metal silicate phosphor activated with divalent europium, the chemical composition of which is (Ba_3_-_a_-_b Eu_ a, M_b)O
It is represented by _3.
, x, y, and z are each in the following ranges: 0.005≦a≦1.5 0≦b≦0.5 0<x≦8 10≦y≦50 0<z≦3.5 Fluorescent material.