JP3264045B2 - Phosphor manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a phosphor, and more particularly to a method for producing a terbium-activated rare earth borate phosphor having a wavelength of 147 nm by a rare gas discharge. is there.

[0002]

2. Description of the Related Art In recent years, there has been a demand for an increase in the size and flatness of a display, and research and development of a color plasma display panel utilizing light emission in a vacuum ultraviolet region by rare gas discharge have been advanced.

A terbium-activated rare earth borate phosphor is known as a phosphor which emits and emits light in the vacuum ultraviolet region.

Conventionally, a method for producing a terbium-activated rare earth borate phosphor has been carried out in air.

[0005]

However, in such a conventional method, since sintering is performed in air, trivalent valent terbium involved in light emission cannot be obtained efficiently.

An object of the present invention is to provide a method for producing a phosphor capable of efficiently obtaining trivalent terbium and thus obtaining a phosphor of high luminance.

[0007]

According to the method for producing a phosphor of the present invention, a rare-earth oxide and boric acid are fired in a reducing atmosphere to excite and emit light in a vacuum ultraviolet region, and the general formula is a (R _1-x , Tb _x ) ₂ O ₃ .bB ₂ O ₃ (where R is at least one of Y, La and Gd;
And when X is a molar amount and b / a is a molar ratio, it is 0.
It is intended to obtain a fluorescent body that you express by 06 ≦ X ≦ 0.12,1.0 ≦ b / a ≦ 1.3).

[0008]

With this configuration, the emission luminance of the phosphor can be improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

First, 20.55 g of yttrium oxide, 3.29 g of terbium oxide, 150 ml of 6N nitric acid, and 42 g of oxalic acid dihydrate are prepared as phosphor materials.

After dissolving the rare earth oxide in the heated nitric acid, pure water is added to form a solution A.

Next, the above oxalic acid is dissolved in heated pure water to prepare a solution B. The solution B is added to the solution A, and the rare earth is coprecipitated as an oxalate, washed with water and dried. This is placed in a heat-resistant container such as an alumina crucible, and oxalate is thermally decomposed at 800 ° C. to 1000 ° C. in an electric furnace to obtain 22.7 g of rare earth oxide.

[0013] 11.8 g of boric acid is weighed to the oxide thus obtained and mixed well in a mortar or the like. Thereafter, the mixture is put in a heat-resistant container, filled with a mixed gas of nitrogen and hydrogen to block oxygen, and baked at a temperature of 1100 ° C. to 1300 ° C. for 3 hours to 6 hours to obtain (Y, Tb) ₂ O ₃ - 1.1
28.1 g of B ₂ O ₃ are obtained.

Thus, a terbium-activated rare earth borate phosphor is obtained. FIG. 1 shows the emission spectrum. From FIG. 1, it can be confirmed that this phosphor has a maximum peak at 544 nm and is a green phosphor.

The luminous intensity of the terbium-activated rare earth borate phosphor according to the embodiment of the present invention is set to 100 with the luminous intensity of the terbium-activated rare earth borate phosphor obtained by the conventional manufacturing method of firing in air. FIG. 2 and FIG. 3 show the results of the relative comparison.

From the results of the experiment shown in FIG.
The range of 06 ≦ X ≦ 0.12 is preferable. That is, when X is less than 0.06, the terbium concentration is low, so that it cannot play a sufficient role as an activator, and the emission intensity becomes insufficient. On the other hand, when X exceeds 0.12,
Because terbium becomes excessively mixed and concentration quenching occurs,
The emission intensity decreases.

From the experimental results shown in FIG. 3, the molar ratio b
/ A is preferably in the range of 1.0 ≦ b / a ≦ 1.3. That is, when b / a is less than 1.0, the amount of boric acid becomes stoichiometrically insufficient, the chemical composition becomes unstable, and sufficient emission intensity cannot be obtained. When b / a exceeds 1.3, the excess boric acid acts as an impurity, so that the emission intensity decreases.

According to the above embodiment, the emission intensity can be improved by 20% as compared with the conventional manufacturing method. Note that the actual
General formula _{a (R 1-x, Tb} x) is施例 with ₂ O ₃ · bB ₂ O ₃
The case where R is Y among the phosphors represented will be described.
However, when R consists of La or Gd, R is Y, L
a or Gd, or R is
The above is also applied to the case where all of Y, La and Gd are used.
The same effect as in the example can be obtained.

[0019]

As described above, according to the present invention,
It is possible to obtain an emission intensity improving effect of up to 20% as compared with the conventional manufacturing method. Therefore, the present invention is useful for a color plasma display panel utilizing light emission in a vacuum ultraviolet region by rare gas discharge.

[Brief description of the drawings]

FIG. 1 shows an emission spectrum of a phosphor obtained by a production method of the present invention.

FIG. 2 is a view showing the relative emission intensity of a phosphor manufactured by changing the molar amount X in an example of the present invention.

FIG. 3 is a view showing the relative emission intensity of a phosphor manufactured by changing the molar ratio b / a in an example of the present invention.

Claims (1)

(57) [Claims] Claims: 1. A rare earth oxide and boric acid are fired in a reducing atmosphere to excite and emit light in a vacuum ultraviolet region.
The general formula is a (R _{1 -x} , Tb _x ) ₂ O ₃ .bB ₂ O ₃ (where R is at least one of Y, La and Gd, and X is a molar amount, and b / When a is a molar ratio, 0.06 ≦ X ≦ 0.12, 1.0 ≦ b / a ≦ 1.
The method for producing a phosphor, characterized in that to obtain a fluorescent body that is Ru represented by 3).