JPS5993783A - Fluorescent substance of blue green emission - Google Patents

Abstract

PURPOSE:A fluorescent substance of blue green emission excited with ultraviolet rays and visible radiation in a blue range, consisting of an alkaline earth metal aluminate activated with bivalent Eu having a specific composition formula. CONSTITUTION:The desired fluorescent substance of green emission shown by the composition formula (X is in 0.01<=X<=0.30; m is in 0.5<=m<2.0; n is in 4<= n<6). In order to obtain the fluorescent substance, for example, SrCO3 is blended with Al2O3, 3MgCO3.Mg(OH)2, Eu2O3, AlF3.3H2O, etc. in a blending ratio to make the composition ratio, the blend is put in a heat-resistant container such as quartz boat, and calcined in a reducing atmosphere such as a mixed gas flow of N2 and H2 at about 1,000-1,300 deg.C. EFFECT:Stable when it is applied to a fluorescent lamp, etc., having low reduction in output of emission throughout life of the lamp.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in a blue-green emitting phosphor comprising an alkaline earth metal aluminate activated with divalent europium.

Structure of conventional examples and their problems Conventionally, aluminate phosphors emit light in the blue-green wavelength range when excited by ultraviolet rays or cathode rays.
As shown in Publication No. 22836, strontium magnesium activated with divalent europium
Aluminate phosphors are known. However, these strontium 1 magnesium aluminate phosphors activated with divalent europium are described in references J, M,
P.J.

Verstegen, D. Radiolovic
and I, E, Vrenken.

J, Electrochem, Soc, 121 (
12), 1627-1631 (1974), it is extremely unstable when applied to fluorescent lamps, and a significant drop in luminous output during the lamp life is unavoidable. Therefore, it was apparently suitable for practical use.

OBJECTS OF THE INVENTION The present invention provides a strontium magnesium aluminate phosphor activated with divalent europium which overcomes the above-mentioned drawbacks.

Structure of the Invention The blue-green light-emitting phosphor of the present invention was obtained through detailed study of the conventionally known strontium-magnesium-aluminate phosphor activated with divalent noeuropium. and its chemical composition is (Sr2-xEuXo2)・mMgoIInAj22o
3, in which each of x, m and n is 0.01≦
X≦0,30 0.6≦m(2,.

Only if it satisfies 4≦n<6, its emission peak/wavelength 1'j-1 is in the blue-green region of approximately 480 to 490 nm, is stable when applied to a fluorescent lamp, and has a long lamp life. Practical I-I with less low F of light emission throughout the inside
J Noh.

DESCRIPTION OF THE EMBODIMENTS The inventors have investigated the composition of the conventionally known strontium magnesium aluminate phosphor activated with divalent europium and the stability of such a phosphor when applied to a fluorescent lamp. After a detailed study of the relationship between fluorophore and phosphor properties, we found that a stable phase exists by limiting the matrix composition of the fluorophore, and it is possible to activate it with divalent europium for practical use. This makes it possible to realize a strontium-magnesium aluminate phosphor.

In order to obtain the phosphor of the present invention, a compound of the constituent elements in the chemical composition formula, for example, 5rGO, A) 20°3Mg
GO3m Mg (OH)2@3H20, Eu2O3
, iF3# 3H20, etc. in a mixing ratio that gives the above chemical composition, place this mixture in a heat-resistant container such as a quartz board, and place it in a reducing atmosphere such as a mixed gas flow of nitrogen and hydrogen. 1 around 1000-1300'fi in
1'ii: Baking is carried out at 30°C for a desired time.

As will be detailed later, the phosphor of the present invention emits blue-green light when excited by ultraviolet rays and visible radiation in the blue region. A strontium-magnesium-aluminate phosphor activated with divalent noeuropium is suitable for wood quality (but if part of the strontium is replaced with barium, calcium, etc. as is generally done), If the amount of substitution is small, the same effects and effects as those of the phosphor according to the present invention can be obtained.

The reason for limiting the range of m and n in 2 will be described below. When m is a value of 2 or more, for example, the emission peak wavelength is 500 to 520 nm due to ultraviolet excitation at 2641 m.
When we investigated whether it would emit light efficiently in the green area in the vicinity or whether it could be applied to fluorescent lamps, we found that the binder is removed during the baking process in step 2 of the phosphor coating process in the normal lamp manufacturing process. It was observed that there was significant deterioration in the In addition, when m is less than 0.5, the luminous efficiency is low, so that it is appropriate to use two LEDs.

On the other hand, if the value is n or 6, "-," for example, 264 nm, like the conventional strontium-magnesium-aluminate phosphor activated with divalent noeuropium.
The emission peak wavelength is 463-476n due to ultraviolet excitation of
Although a fluorescent lamp that emits light efficiently in the blue-green region of It has been confirmed that when applied to the above, there is significant deterioration during the baking process and throughout the life of the product. Furthermore, if n is less than 4, a stable phosphor cannot be obtained;
The luminous efficiency was also so low that it could not be used for practical use.

In the above range, especially when m is 1.0 to 1.6 and n is 4.5 to 5.5, the emission peak wavelength is approximately 480 to 490 nm, which is an efficient light emission in the blue-green region. It has become clear that this is particularly preferable because it becomes a stable phosphor even when applied to a fluorescent lamp.

Next, regarding the europium content X, the reason for limiting it to the above range is that it is less than the F limit, and it is difficult to obtain an effective light output even though expensive europium is used liberally. This is due to the fact that it is not available.

As described below, the blue-green emitting phosphor according to the present invention can be used as a luminescent screen for fluorescent lamps, mercury lamps and cathode ray tubes, and is suitable for fluorescent lamps from the viewpoint of the emission spectrum. When applied to the normal fluorescent lamp manufacturing process, the phosphor is used after being dispersed in an organic solvent or water containing a binder to temporarily form a coating film such as nitrocellulose. The phosphor of the present invention has commercial stability even when subjected to heating during the baking process to remove the binder, and has the advantage that the luminous efficiency does not decrease too much. Specifically, the conventional strontium macnesium aluminate phosphor activated with divalent europium can be heated to about 20 to 3
In contrast, the phosphor of the present invention has a low luminous efficiency of about 6 to 7%, which is significantly improved.

A very important advantage of the phosphor of the invention is that it can be excited not only by ultraviolet radiation, but also by visible radiation in the blue region. The mercury line spectrum in the blue region of 406 nm and 436 nm emitted from a fluorescent lamp has low visibility, so it does not contribute much to the luminous efficiency of the fluorescent lamp, but the phosphor of the present invention It is excited by the mercury line spectrum and emits light with a long afterglow in the blue-green region, making it the fourth most useful phosphor for fluorescent lamps.

Embodiments of the present invention and conventional examples will now be described with reference to the drawings.

According to the chemical composition shown in Table 1, compounds of the constituent elements were prepared as follows.

Example 1 SrC0,1, 35 mols Mgco3-Mg(OH)2-3H200, 175 mol A, 034.90 mol Eu, 050.076 mol A4F3-3H, 00,40 mol These were mixed using a ball mill. After mixing, fill the quartz port and heat in a mixed gas of nitrogen and hydrogen at 1000~13oO
It was baked for 2 hours at a temperature of °C. The obtained fired product was cooled in the same atmosphere, crushed using a ball mill, and then fired under the same conditions for 2 hours to obtain a phosphor.

Example 2 SrCO31,sγ mol Mho 0.60 mol M
gF2 0.50 -EruAno, O35,00 molEu2o30.065 mol Actual power 3 Sr (No3), 1,97
Mol 3MgGO3-Mg(OH),,-3H20
0,30 mol Aff12036.60 mol Eu2O3 0,015 mol A4F3 0.20 mol Example 4 SrCO3 0,96 mol 5rC4, 0,96 mol 3 MgGo3-M7(OH)2-3H200, 376 mol A40. 4.60 molEu2O3o, 04 mo)l/ Conventional example SrCO36,00-T:j3Mgco5・'Mg(OH),,・3H201,00
Mol MgF,
2.00 Molshi Ano, 05
27.50
Mol Eu206
0.26 -Eel/Examples 2, 3.
4 and Conventional Examples'' A phosphor was obtained in the same manner as in Example 1.

Table 1 shows the emission peak wavelength and relative brightness of each of these phosphors when excited with 264 nm ultraviolet light.

Next, 5r5Euo and 5M, which are representative strontium magnesium aluminate phosphors activated with divalent europium in Examples 1 and 4 and the conventional example, were used.
g6A4. Figure 1 shows the emission spectrum of the Q,4 phosphor when excited by ultraviolet light at 2641 m.

In the figure, curve 1 shows the case of the first embodiment, curve 2 shows the case of the fourth embodiment, and curve 3 shows the conventional example. 1st
According to the figure, the phosphor according to the present invention radiates most of its luminous energy into the phosphorescent region, and especially the strontium magnesium aluminate fluorescein activated with divalent europium of the conventional example. Compared to the body, 440nmJ2
1. It has the characteristic that it radiates almost no energy in the wavelength range of 'F.

Next, using the phosphors of Examples 1 and 4 described above and the conventional example, a 40W $ tube type fluorescent lamp was made as usual, and the characteristics were compared. It became.

As shown in Table 2, the lamp using the phosphor of the present invention clearly has superior performance in terms of luminous efficiency and maintenance rate compared to the lamp using the conventional phosphor. It has been improved to a practical level.

”-parameter m in the composition formula of Example fl12.

Fluorescent materials with varying n and X were made and their properties were measured. The live eyes are shown in Figures 2, 3, and 4.

It is shown in FIG.

Figure 2 shows the chemical composition formula Sr, , a7Euo, , 50. , -mMgo-
For the phosphor designated as sA403, the change in m is 25
It shows the relationship between the luminance of light emitted by excitation with 4 nm ultraviolet light.

Further, FIG. 3 similarly shows the change in the rate of brightness deterioration in the above-mentioned baking process for removing the banquet due to the change in m. In the figure, the vertical axis represents the maintenance rate (%) of luminance before and after the printing process. From FIG. 3, it can be seen that when the value of m is 0.6 or more and less than 2.0, the luminance is maintained when the lamp is used. Further, m is particularly preferably in the range of 1.0 to 1.5 because a stable phosphor can be obtained.

On the other hand, in Fig. 4, the chemical composition formula is SrI, 87"uO, +302- MgO* n4f
For the phosphor denoted by f1205, changes in the rate of brightness deterioration in the same printing process as described above due to changes in n are shown. In the figure, it can be seen that stable luminance is obtained when the value of n is 4 or more and less than 6.

'gg Figure 6 shows the results of measuring the change in luminance of a phosphor having the chemical composition formula Sr2-XEuxO2-MgO-6A403 upon excitation of ultraviolet light at 2541 m. From the figure, it can be seen that effective light emission can be obtained with the value of X or Q in the range of 01 to 0.3.

Effects of the Invention - As explained, the present invention has a chemical composition formula (Sr2-xEu
x02)・mMg0−nAi203, and m.

n and X each satisfy 0.01 ≦X≦Q, 30 0.5≦B) There is 1i with blue-green color,
In addition, it is suitable for fluorescent lamps, is stable in terms of f1, and has a practical and improved blue-green emitting phosphor, which has a longer lifespan than conventional lamps and has less low color light output. It is something that can be provided.

[Brief explanation of the drawing]

FIG. 1 shows representative examples of the present invention. Figure 2 shows the emission spectrum of Lid-1 (d 151
~ Indicates the relationship between the chemical composition m of the light body and the luminance 1-ID
, 31st and 4 respectively show the chemical composition of the same phosphor. Diagram showing the relationship between n and retention rate, 61st sub 1iiJ firefly)
FIG. 3 is a diagram showing the relationship between the chemical composition of the wood and the luminance. Name of agent Patent attorney Toshio Nakao C1 or 1 person 1st staff member ☆ (nrr)) Figure 2 Figure 3 υ,,) 1. lJ 1.
,) '1.0', 'ΦFig.5

Claims (1)

[Claims] An alkaline earth metal aluminate phosphor activated with divalent europium, the chemical composition of which is: (Sr, , EuxO2)-mMgo-nA4203
In the formula, x, m and n are each 0.01≦X
≦0.3゜06≦m〈2. A blue-green light-emitting phosphor characterized by adding 45 n ri 6 to 7I:l''11.