JPS5852382A - Europium-activated yttrium oxide fluophor - Google Patents

Abstract

PURPOSE:To provide the titled fluophor having an excellent crystallinity and improved initial efficiency and resistance to degradation, prepared by adding an aluminum compd. to a primarily burned mixture of raw material oxides, followed by secondary burning. CONSTITUTION:Yttrum oxide and europium oxide are dissolved in a conc. nitric acid and oxalic acid (or dimethyl oxalate) is added to the solution for coprecipitation of yttrium/europium/oxalate. The coprecipitate is burned at around 900-1,110 deg.C for about 2hr for convertion to an oxide. Then about 0.01- 0.3mol of aluminum phosphate (or aluminum oxide) is added to 1mol of the above primarily burned product and the mixture is subjected to secondary burning at 1,200 deg.C or higher to form a Eu-activated yttrium oxide fluophor with an aluminum content of 100-4,000ppm.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to europium activated yttrium oxide phosphors.

The europium activated yttrium oxide phosphor is formed in a conventional manner. First, yttrium oxide Y, 01
and europium oxide (Eux) are dissolved in 1!11 nitric acid, *m dimethyl or # acid is added to this mixed nitric acid solution to form oxalate (Y, -x,, Eux)t (Ox 04
) Co-precipitate a. This precipitate was heated to 900° to 1100°C.
After sintering for 2 hours, the oxide (Ys-x, Eux)
Set it to Oh.

Further, this oxide is subjected to secondary firing at 1400° C. for 5 hours.

After firing, it is crushed to produce europium-activated yttrium oxide Yl.
OH: Use Eu phosphor. - In the secondary fired oxide, europium is activated and introduced into the yttrium atoms by secondary firing at a high temperature of 1200°C or higher, resulting in % Y, 6. : Forms Eu phosphor.

In the phosphor formed in this way, yttrium oxide and europium oxide are stable, and europium can be completely introduced into yttrium atoms by secondary firing, and since the reactivity is low, crystallization is possible. make one's sexuality bad.

This invention provides a modified europium-activated yttrium oxide phosphor that eliminates these drawbacks, namely, by adding either aluminum phosphate or aluminum oxide to the raw material oxide formed by primary firing. Te120
It is a europium-activated yttrium oxide phosphor in which 100 to 4000 ppm of aluminum is added to the ingredients by secondary firing at 0° C. or higher.

The phosphor of the present invention is formed as follows. First, yttrium oxide and europium oxide are dissolved in concentrated nitric acid, and dimethyl oxalate or oxalic acid is added to this mixed nitric acid solution to coprecipitate yttrium europium oxalate.
This precipitate is then calcined at 900 to 1100° C. for 2 hours to convert it into an oxide.

The steps up to this point have followed the conventional phosphor formation process. The difference is that aluminum phosphate A#PO or aluminum oxide is added from 0.001 to 1 mole during oxidation.
0.03 mol was added, mixed, and secondarily fired at 1400° C. for 5 hours. The fired product is pulverized to obtain the europium-activated yttrium oxide phosphor of the present invention.

Here, (Y,
Table 1 shows the results of analyzing the phosphor after secondary firing by changing the amount of aluminum phosphate added to 1 mole of OH.

'' (side, r'i7 white) Figure 1 shows the relationship between the molar addition amount of aluminum and the amount of phosphor attached [1] when an aluminum compound is added to 1 mole of the primary fired oxide. .Curve A was taken using aluminum phosphate, and curve opening was taken using aluminum oxide.
It's Nitto.

The horizontal axis also shows the amount of aluminum (ppm) in the corresponding phosphor component 16'.

FIG. 2 shows the lamp deterioration characteristics of 40W fluorescent lamps for low-pressure mercury lamps prepared using the Example phosphor (2) shown in Table 1 and the Comparative Example phosphor without addition of aluminum. The vertical axis represents the relative value of the fluorescent lamp, the horizontal axis represents the lighting time (hours), the curve A represents the example phosphor, and the curve end represents the comparative example phosphor.

Next, primary firing oxidation d#IJ (Y+ -z, Eux
Table 2 shows the flux addition amount, relative brightness, 100 hour lamp maintenance rate, crystal grain size -), and phosphor adhesion amount relative to a 40W mercury lamp for the comparative and example phosphors based on )tO, .

From Table 2 for each machine size, the example phosphor has a relative brightness of 10 when the europium oxide concentration is the same as that of the comparative example (1) phosphor.
The 100-hour lamp maintenance rate showed a 3-factor improvement effect. On the other hand, in the case of the phosphor of Comparative Example (1), the concentration of expensive europium oxide in the material of the insole must be increased in order to equalize the relative brightness. In Comparative Example (2), the europium oxide concentration was increased to X=0.1120 to increase the brightness. Furthermore, compared to the phosphor of Comparative Example (3), the Example phosphor improved the relative brightness by two points and significantly reduced the amount of phosphor deposited per lamp. On the other hand, since the phosphor of Comparative Example (3) has a large crystal grain size, it is not preferable to require a large amount of coating.

The phosphor of the present invention contains europium in order to contain aluminum with a valence of +3 equal to that of the activator.
J is introduced well into the aluminum to improve crystallinity and improve initial efficiency and deterioration characteristics.

[Brief explanation of drawings]

Figure 1A shows the molar ratio of aluminum added when each aluminum compound is added to 1 mole of the primary fired oxide, and the amount of aluminum in the corresponding phosphor component ppm and phosphor powder. 2A and 2B are diagrams showing the relationship with luminance, and FIG. 2B is a diagram showing lamp deterioration characteristics of fluorescent lamps related to the example phosphor and the comparative example phosphor, respectively. Agent: Patent attorney: Inoue - Male Procedural amendment (method): Commissioner of the Japan Patent Office: Shima 1) Haruki Tono1, Indication of the case, Patent Application No. 150767 filed in 1982, 2, Title of the invention: Eurobicum-activated yttrium oxide phosphor 3 , Relationship to the case of the person making the amendment Patent ratio - Person (307) Tokyo Shibaura Electric Co., Ltd. 4, Agent 〒144㎜ Date of amendment order: January 5, 1980 (Shipping date: January 26, 1980)
Column 7 of the brief description of the drawings in the specification subject to amendment, Contents of amendment (1) Delete "a, a" on page 6, line 20. (Illusion, page 7, line 1, ``against'' is changed to ``of aluminum phosphate or aluminum oxide.'' 4) Line 4 of the same page, ``Diagram showing the relationship, Figure 1112 A 1 mouth is sequential'' is a line diagram showing the r@IA section with curve A or B i 2, 4
Figure 2 is ``. (5) Line 5 of the same page [and each related to the comparative example phosphor] shall be changed to ``or each related to the comparative example phosphor.'' (6) On the same page, in line gJ6, ``show'' is changed to ``show in i or mouth, respectively.''that's all

Claims (1)

[Claims] Adding either aluminum phosphate or aluminum oxide to the raw material oxide formed by primary firing
A europium-activated yttrium oxide phosphor, characterized in that 100 to 4000 ppm of aluminum is added to the ingredients by secondary firing at temperatures above ℃.