JPH04198390A - Barium-aluminate-based fluorescent substance and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title fluorescent substance suitable for fluorescent lamp of three waves, having both high luminous intensity and excellent color rendering properties by adding boric acid as flux to a raw material. CONSTITUTION:A raw material comprising boric acid as flux besides compounds of Ba, Ca, Eu, Mn and Al is calcined in the atmosphere preferably at 1,250-1,300 deg.C, ground, then further burnt in a reducing atmosphere preferably at 1,300-1,500 deg.C to give the objective fluorescent substance shown by the formula (1.20<=x<=1.29; 5.00<=y<=7.00; 0.005<=z<=0.20) and activated by both bivalent Eu and bivalent Mn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a barium-aluminate-based phosphor that emits blue light when excited by ultraviolet light.

[Prior Art] Generally, in order to obtain a high color rendering property (a measure of how the object color looks natural when the object is irradiated) with a fluorescent lamp, the wavelength is 450.
3 nm (blue), 540 nm (green), 610 (red) nm
Narrowband color spectra are combined to create an emission spectrum close to that of a blackbody. For this reason, various phosphors ranging from blue to red are required.

Conventionally, as a blue phosphor, a barium-magnesium-aluminate-based phosphor has been used, which is excited by ultraviolet light having a wavelength of 253.7 nm and has an emission wavelength peak (hereinafter referred to as peak) at 450 nm. In addition, in order to obtain blue-green luminescence, we use a halium-magnesium-aluminate system activated with europium (an ion added to incorporate a luminescent center that causes luminescence into the base material crystal is called an activator). Photon, e.g. Ba Mg2 Al, 40
24: Eu"" can be further activated with divalent manganese to utilize the subpeak (a green subpeak is generated by activation of manganese), or by adding a fluorophore having a peak around 490 nm. Something is being done.

As a barium-magnesium-aluminate phosphor activated with divalent europium and divalent manganese,
For example, there is one disclosed in Japanese Patent Publication No. 5B-22496, which was highly promoted by europium.
It is said that there is little deterioration.

[Question to be solved by the invention] However, in the prior art as described above, in order to improve the color rendering properties, pallium-magnesium-aluminate-based phosphor is used as a donor of europium and manganese, and different When a phosphor having a peak at a wavelength is added, there is a problem in that the luminescence intensity in the blue region decreases.

The present invention has been made in view of the above points, and an object of the present invention is to provide a blue phosphor that can obtain high color rendering properties and improve the luminescence intensity in the blue region compared to the conventional one. The purpose is to

[Means for Solving the Problems] In the present invention, the general formula x(Ba, Ca)O. yAl2O:+:E
2 traces of europium and 2
In the barium-aluminate phosphor activated with manganese, where x, y, and z are 1.20≦x≦1.29, 5.00≦y≦7.00゜o
, the above problem is achieved by setting the range of oos≦Z≦0.20,
It is preferable that the molar concentration of Ca with respect to the total of Ba, Ca, Eu and Mn is 7 to 9+no1%i. Further, the barium-aluminate-based phosphor of the present invention is obtained by adding boric acid as a flux to a raw material consisting of a compound of barium, calcium, europium, manganese and aluminum and firing it in the atmosphere. It is produced by grinding a mixture of oxides and then calcination in a reducing atmosphere.

At this time, the concentration of boric acid relative to the entire raw material was adjusted to approximately 0.23w.
It is preferable to set it as t%:.

[Function] The present inventors have developed a barium-hexaaluminate-based phosphor x (Ba, Ca) 0.68120. which has a peak on the slightly shorter wavelength side than the barium-magnesium-aluminate-based phosphor. : Focusing on Eu"", in order to improve the color rendering properties, it was combined with a small amount of manganese.

Furthermore, regarding the barium and calcium concentrations (value of X in the above equation), the emission intensity is 1.26<1.27<1.211<1.29 and
= 1.29, and rapidly decreased at 13o, and set the range of X to be 1.20 to 1.29, preferably 1.26 to 1.29.

Furthermore, we focused on the molar concentration of calcium in barium, calcium, europium, and manganese, and set this to 7 to 9 m
By turning it on, we aimed to improve the emission intensity in the blue region.

Here, the role of calcium in the present invention will be explained.

The emission spectrum of the calcium-free pallium-hexaaluminate phosphor 1.29Bao・6A120s:Eu2'' starts at a wavelength of 390 nm and has a wavelength of 450 nm.
It shows a gentle downward curve with a peak at nm up to around 650 r+m in the long wavelength region. Therefore, there are many edge components in the emitted light, and when excited with a mercury line with a wavelength of 254 nm, the color becomes blue, which is close to white. Therefore, in the present invention, Eu in the crystal is
By partially replacing `` with calcium, which has a peak at a short wavelength of 416 ns and has a small emission range at long wavelengths, 443
It is designed to create a strong peak at nm. At this time, when the molar concentration of calcium relative to the total of barium, calcium, and europium is in the range of 7 to 9I110196, the emission intensity at a wavelength of 443 nm is high, and when it exceeds 1Omon, violet emission occurs and the blue emission intensity decreases.

When replacing a portion of barium with calcium, there is a problem that calcium is difficult to enter the aluminate as it is, but in the present invention, by adding boric acid to the raw material, the replacement of barium with calcium can be achieved. is promoting.

Furthermore, when a small amount of aluminum chloride is added to the raw material in addition to calcium, the luminescence intensity in the blue region is further improved.

Next, as raw materials for the phosphor of the present invention, carbonates, nitrates, halides, and other substances that decompose into oxides at high temperatures can be used. Specifically, barium carbonate (BaC
O3), calcium fluoride (CaF2), europium oxide (ELI2(13)), aluminum oxide (Al
2O2), chloride 7 Lumi-1-UL (AIC138
H20), 7 Yttrium fluoride (YF3), etc. can be used.

The temperature at which the above raw materials are fired and oxidized in the atmosphere is 1
Preferably, the temperature is 250°C to 1300°C, and the temperature during subsequent firing in a reducing atmosphere is preferably 1300°C to 1500°C. In order to perform reduction firing efficiently,
It is good to add a small amount of 8LF3.

[Example] Example-1 1,29(8a,Ca)0.6AI203:Euol
Fix the amount of europium for the phosphor shown in
The results of examining the luminescence characteristics by varying the concentrations of calcium and barium are described below.

The concentrations of Ca, Ba, and Eu in each sample are shown in Table 1, and the luminescence characteristics of each sample are shown in Table 2. Further, FIG. 1 shows the emission spectra of each sample, and FIG. 2 shows the relationship between the concentration ratio of calcium and barium and the relative emission intensity. In addition, in the table,
IP is the relative luminescence intensity compared at the highest luminescence energy of each phosphor, and Re1. Y indicates the luminescence intensity by a number obtained by correcting the luminosity of the phosphor. Further, H and W have half widths, which, in the case of a phosphor for a lamp, are important requirements for increasing the amount of light and the color rendering effect.

Table 1 Table 2 ST/calcium concentration 8 mol ¥.

As shown in Figures 1 and 2, calcium Loo
From sample 1 (contains a certain amount of europium) to samples 2 and 3.4, the emission intensity in the blue region increases as the amount of barium increases, reaching its maximum at a calcium concentration of 8, and the half-width becomes narrower and sharper. A peak occurs. However, furthermore,
Barium ID is increased like sample 5 by increasing the barium content.
096 (containing a certain amount of europium), the emission intensity decreases, the half-width also increases, and the spectrum ends up tailing toward the long wavelength region.

Next, FIG. 3 shows the chromaticity graph of each sample, and sample 5 of barium 10Dk is far away from the sample on the chromaticity coordinates. This is due to sample 5 as mentioned above.
The emission spectrum or long wavelength range (390 to 650 nm)
The color of the emitted light appears to be close to white. Sample 4 and the reference sample with a calcium concentration of 8% F show blue color, and sample 1 with calcium concentration of 100 shows purple light emission.

From the above results, it can be seen that the luminescent color and luminescent intensity vary depending on the calcium concentration, and that blue luminescence reaches its maximum around 8 moIN.

Example-2 In order to determine the appropriate range of calcium concentration in more detail, 1.29 (Bap, Caq, Euo, 1)o・aA
For the phosphor shown as 12o3, the concentration ratio of the metal in parentheses was fixed to 10mol of europium and 1%; and the calcium concentration was varied in the range of 25 to 9.0 mol to adjust the luminescence characteristics of the phosphor. clumsy.

The results are shown in Table 3, and the relationship between calcium concentration and relative luminescence intensity (assuming the intensity of a turtle with a calcium concentration of 8 mol as 10096) is shown in FIG.

Table 3 5T Barium-magnesium-aluminate-based phosphors.

As shown in Figure 4, the calcium concentration is 7-9 mol.
The blue light emission intensity is high, and the calcium concentration is 5 mol! l; and 9 mol! Above that, the luminous intensity is insufficient. Furthermore, in a turtle with a calcium concentration of 2.5 mol, the emission intensity is only 88.5 zero when the calcium concentration is 8 mol, and the spectrum has a tail in the short wavelength region as can be seen from the chromaticity coordinates.

Example 3 The results of a study on the effect of adding boric acid are described below.

0.23 wt% of boric acid (83BO3) based on the total amount;
, phosphor 1.29 (Bao, a2.
Cao, oa, Euo, +)0.6AI203,
The luminescent properties of phosphors manufactured without the addition of boric acid were investigated.

FIG. 5 is a graph showing emission spectra with and without boric acid added.

From the figure, the one with boric acid added is 500 to 53 on the long wavelength side.
It can be seen that the emission intensity at 0 nm is reduced and the blue emission intensity is improved.

The concentration ratio of barium, calcium, and europium is almost 0.
．． 82:0.08:0.1, by boric acid]
Therefore, it is thought that some kind of electron exchange within the crystal field (for example, due to lack of oxygen ions) takes place.

Example 4 Prior to trial production of a barium-aluminate phosphor activated with europium and mankan, Example 4.5 shows an example in which a barium-hexa-aluminate phosphor activated with a europium car was manufactured. .

Barium carbonate 82.82g Calcium hookah 242g Europium oxide 6.81g Aluminum oxide 183.10g Aluminum chloride
C35g Boric acid O8δog Mix the above raw materials and place in an alumina tray at 600℃~1
After decomposition and firing in the air at 300° C. for 5 hours, the obtained oxide was thoroughly ground in a whole mill. This powder was filled into an alumina tray and subjected to reduction firing again within the range of 1350'C to 1500C for several hours. The composition of the phosphor thus obtained is as follows.

1.29(Ba,,62CaO,o6EuO,+)o
, 6A1203 The height of the emission peak of this phosphor due to ultraviolet excitation is c) Noumu magnesium-aluminate phosphor (Bao, 90ELIO, l) Mg+, s
, compared to the emission peak height of AIl+019.1, which is 10
6*, a clear improvement.

Example-5 Barium carbonate 62.62g Hooka calcium 242g Europium oxide 5.40g Aluminum oxide 183.10g Aluminum chloride
4.35 and boric acid 0.5 og Using the above raw materials, a phosphor was obtained in the same manner as in Examples to 4. The composition of this phosphor is as shown below.

1-29 (Bao, an+Cao, ot94Euo, o
t9n)0. 58120:1 The height of the emission peak of this phosphor due to ultraviolet excitation is halium-magnesium-aluminate phosphor (Bao9EUol) Mg+, a, A
Compared to the emission peak height of I++02o, IO was clearly improved or enriched.

Example-6 Halium-hexaraluminate phosphor, composition 1.29
(Baa 112 Ca,) oa) (1,5AI20
3:Eu" was used as a donor with divalent mankan, and the emission spectra were measured when the concentration of mankan was varied. The results are shown in Figure 6. In addition, the peak intensity etc. Table 4 shows the timekeeping properties, and Figure 7 shows the changes in chromaticity coordinates.Furthermore, Table 5 summarizes the shift of the peak position due to a 14 degree change in manganese (manganese), and the intensity of the sub-peaks. .

Table 5 Peak wavelength Sub-peak wavelength Sub-peak intensity* HW (nm) (nm)
1) 441 (Eu, P)
500 (Mn, P) 12,8
53.82) 441))
507 Horn 1
3.65 53.73) 442
of! 510 Horn
15.59 53.84
) 438 ))
517 Horn 2fi, 3
7 53.85) 436))
517) l 36.48
68.76) 517(Mn, Pl
438 (Eu, P) 8 (1,9071,
8. The sub-bik intensity % is (manganese peak intensity Mn, P) / (europium peak intensity Eu, P + manganese peak intensity M)
n, P) According to these data, if the amount of manganese is changed while keeping the europium concentration constant, the amount will be lower than that of sample N.
o.3, the main peak at 443 nm is strong. However, when the molar concentration of manganese becomes 0.05 mol or more, the subpeak gradually shifts to 517 rv. As a result, the main peak is affected and moves to the shorter wave side. In sample No. 6, the main peak is replaced, the emission wavelength due to europium becomes a sub-peak, and the emission color is blue-green.

The blue emission intensity when europium and manganese are co-activated is 1009.
In order to obtain 85 zero or more as 6, the effective range of the manganese concentration 2 to be replaced with barium is as follows: Blue emission: 0 < Z < 0.0015 mol; Blue-green emission: 0.005 < z < 0.20 mol.

Although it depends on the crystal matrix, the peak position of manganese Mn2" itself is approximately at 517rv, and the green light emission of manganese Mn2" is obtained by the energy of europium Eu'+, so naturally, if the manganese concentration is increased, the quaternary
As shown in the table and FIG. 6, the blue light emission will be attenuated. This fact can be used to obtain blue-green luminescence, and the value of the chromaticity coordinate can be adjusted by setting the manganese concentration.

Example 7 Next, an example of a barium-hexaaluminate phosphor containing europium and mankan is shown.

Barium carbonate 64.22g Hooka calcium 2.42g Europium oxide 6
．． 81g manganese carbonate 0.23g aluminum oxide 183. lOg aluminum chloride
4J5g Boric acid 0.60g Using the above raw materials, a phosphor was experimentally produced under the same conditions as in Example 5. The composition of this phosphor is as follows.

1.29 (Bao, a+, Cao, oaEIIo +
Mno oos) 0.6^1203 The height of the emission peak of this phosphor due to ultraviolet excitation is the same as that of barium-magnesium-aluminum alloy coactivated by divalent europium and divalent manganese with the same manganese concentration as in the example. light phosphor (Bao, 9 Eua, +) (Mg+,
Compared to the emission peak height of 595 0005)^1110111.1, the improvement was clearly increased to 104 zero.

Example-8 Barium carbonate 63.84g Hooka calcium 2.40g Europium oxide 5.
40g manganese carbonate 0.23g alumina oxide
283.10. g aluminum chloride 4
．． 35g Boric acid 0.60g Using the above raw materials, a phosphor was experimentally produced under the same conditions as in Example 5. The composition of this phosphor is as follows.

1.29 (Bao, 1136cao, 07941:u
o, oteaMno, aas) 0.6^12o.

The height of the emission peak of this phosphor upon excitation with ultraviolet light is the same as that of a halium-magnesium-aluminate phosphor coactivated by divalent europium and divalent manganese (Bao, gEu, gEu, ), +
) (Mg1.s(1'l 1llno, 005)
Compared to the emission peak height of 0.5.5AI203, it is 103
．． 5%i is a clear improvement.

[Effects of the Invention] As described above, in the present invention, by setting the calcium concentration in the halium-hexaaluminate phosphor within a specific range and using boric acid as a flux,
Compared to conventional barium-magnesium-aluminate-based phosphors, the blue light emission intensity has been improved, and by adding europium and manganese, the emission wavelength can be finely adjusted to enhance the color rendering effect. That is, according to the present invention, a blue phosphor having both high emission intensity and excellent color rendering properties can be realized, and such a phosphor can be suitably used in a three-wavelength fluorescent lamp.

[Brief explanation of the drawing]

Figure 1 is a graph showing the emission spectra of each phosphor produced by fixing the amount of europium and varying the concentration of calcium and barium. Figure 2 is a graph showing the relationship between the concentration ratio of barium and calcium and the relative emission intensity. , Figure 3 is a chromaticity diagram showing the chromaticity coordinates of each phosphor with varying calcium concentration, Figure 4 is a graph showing the relationship between calcium concentration and relative luminescence intensity,
Figure 5 is a graph showing the difference in emission spectra depending on the presence or absence of boric acid, and Figure 6 is a graph showing the emission spectra when the concentration of manganese is changed in europium and manganese donor-activated barium-hexaluminate phosphors. ,
FIGS. 7(a) and 7(b) are diagrams showing changes in chromaticity coordinates depending on manganese concentration.

Claims (4)

[Claims] (1) In a barium-aluminate-based phosphor activated with divalent europium and divalent manganese, the general formula x(Ba,Ca)O. yAl_2O_3:Eu^
2^+・ZMn^2^+ However, regarding x, y, and z in the formula, 1.20≦x≦1.29, 5.00≦y≦7.00, 0
．． 005≦z≦0.20. (2) The phosphor according to claim 1, wherein the molar concentration of Ca with respect to the sum of Ba, Ca, Eu and Mn is 7 to 9 mol%. (3) After firing raw materials consisting of compounds of barium, calcium, europium, manganese and aluminum in the atmosphere, the resulting oxide mixture is pulverized, and then
A method for producing a barium-aluminate-based phosphor, which comprises adding boric acid as a flux to the raw materials when producing the barium-aluminate-based phosphor by firing in a reducing atmosphere. . (4) The concentration of the boric acid is approximately 0.23 with respect to the entire raw material.
Barium according to claim 3, characterized in that it is wt.
A method for producing an aluminate-based phosphor.