JPH0629411B2 - Fluorescent body - Google Patents

Description

TECHNICAL FIELD The present invention relates to an indium borate-based phosphor. More specifically, the present invention relates to a novel indium borate-based phosphor that emits light with high brightness by substituting a specific amount of aluminum for part of indium in the phosphor.

(Prior Art) Conventionally, as an indium borate-based phosphor, terbium,
Indium borate phosphors having at least one of europium, dysprosium and samarium as an activator are known (US Pat. No. 3,394,084). This phosphor emits light according to each of the above activators under the excitation of an electron beam or the like.

However, the brightness when these indium borate-based phosphors are used under the electron beam excitation of, for example, a display tube, a projection tube, and a low-speed electron beam excitation fluorescent display tube is still insufficient. With the increase in the cases where it is used under high energy excitation such as high current density, the emergence of ones with more excellent brightness has been desired.

(Problems to be Solved by the Invention) An object of the present invention is to provide an indium borate-based Tb-activated phosphor that emits light with high brightness under the excitation of an electron beam or the like.

The present inventors have conducted various studies on indium borate-based phosphors in order to achieve the above object. as a result,
The present invention has been accomplished by finding that the above-mentioned purpose, luminance, is improved by substituting a part of indium with aluminum.

(Means for Solving Problems) The indium borate phosphor of the present invention is characterized in that a part of indium is substituted with aluminum in an amount of 0.1 mol or less.

The present invention will be described in more detail below.

The phosphor of the present invention can be manufactured, for example, by the method described below.

First, as the raw material of the fluorescent substance, (1) indium oxide (In ₂ O ₃ ) or an indium compound such as nitrate, carbonate, or hydroxide which can be easily converted to In ₂ O ₃ at high temperature, (2) Aluminum oxide (Al ₂ O ₃ ), or aluminum compounds such as nitrates, carbonates, and hydroxides that can be easily converted to Al ₂ O ₃ at high temperature, (3) Boron oxide (B ₂ O ₃ ) or boric acid (H Boric acid compounds such as ₃ BO ₃ ), which can be easily converted to B ₂ O ₃ at high temperature, (4) terbium oxide (Tb ₄ O ₇ ) as an activator raw material, or borate, chloride, etc. easily at high temperature A terbium compound that can be converted to Tb ₄ O ₃ is used as a starting material.

The four phosphors feedstock _{stoichiometrically, (In 1-xy Al x} Tb y) · nBO 3 ( where, x, y and n, respectively, 0 <x ≦ 0.1,0.
It is a number that satisfies the conditions of 0005 ≦ y ≦ 0.1 and 1 ≦ n ≦ 1.5. ) Are weighed so that the compositional formula is

The mixing may be performed dry using a ball mill, mixer mill, mortar or the like, or may be performed wet using a paste state using water or the like as a medium. In particular, from the viewpoint of the emission brightness of the obtained phosphor, the more preferable ranges of the x value and the y value of the above mixed composition formula are 0.001 ≦ x ≦ 0.08 and
0.001 ≤ y ≤ 0.05.

In the production of phosphors, a flux is often added to the phosphor raw material for the purpose of improving the emission brightness of the phosphor generally obtained, powder characteristics, etc., but the phosphor of the present invention is used. Also in the production of the body, by improving the luminous brightness by adding and mixing an appropriate amount of lithium phosphate, an alkali metal phosphate such as lithium chloride, a halide or the like or the above ammonium salt into the phosphor raw material mixture as a flux. be able to. Also, these alkali metals remain in trace amounts in the matrix.

In particular, in the present invention, it has been found that the phosphor of the present invention in which a minute amount of lithium is contained in the phosphor using a lithium compound as the flux is preferable from the viewpoint of brightness and the like.

In this preparation process, in order to obtain a phosphor having high luminous efficiency, it is preferable that the amount of boron is blended in a slightly excessive amount over the stoichiometric amount.

That is, the brightness is higher in the range of 1 <n ≦ 1.5 than that of n = 1. However, when n is larger than 1.5, the brightness is rather lowered, which is not preferable.

In the present invention, the above-mentioned phosphor raw material mixture is filled in a heat-resistant container such as an alumina crucible or a quartz crucible and baked. When the phosphor raw materials are wet mixed, the phosphor raw material mixture is dried in advance. Firing is performed several times in a neutral or reducing atmosphere in air.

The firing temperature is suitably 400 ° C to 1450 ° C, more preferably 450 ° C to 1350 ° C. Further, high temperature firing at 800 ° C. to 1350 ° C. is performed at least once.

The firing time varies depending on the filling amount, firing temperature, etc., but in the above firing temperature range, 0.5 hours to 6 hours is appropriate, and more preferably 1 hour to 5 hours.

After firing, the phosphor is obtained by performing each operation generally employed in phosphor manufacturing such as washing, drying and sieving.

By the manufacturing method described above, the composition formula _{(In 1-x-y Al} x Tb y) · nBO 3 ( here, x and y have the same definitions as described above) borate indium system of the present invention represented by You can get the phosphor. This phosphor emits green light with good color purity under electron beam excitation. Its emission color is the same as that of the InBO ₃ : Tb phosphor. Further, even if the x value and the y value of the above composition formula are changed, the emission color is not changed.

Note that FIG. 1 shows the emission spectrum of the phosphor of the present invention.

The indium borate-based phosphor of the present invention is a known InBO ₃ : T
This is an improved emission brightness of the b phosphor under electron beam excitation, and shows higher brightness of light emission than the InBO ₃ : Tb phosphor under electron beam excitation.

FIG. 2 is a graph showing the relationship between the aluminum substitution amount x value and the emission luminance of the (In _0.995-x Al _x Tb _0.005 ) BO ₃ phosphor of the present invention under electron beam excitation.

In FIG. 2, the emission luminance on the vertical axis is shown as a relative value when x = 0, that is, the emission luminance of the conventional InBO ₃ : Tb phosphor is 100. As is clear from FIG. 2, the phosphor of the present invention has a conventional I in the range of x value 0 <x ≦ 0.1.
nBO ₃ : emits light with higher brightness than the Tb phosphor, especially 0.0
In the range of 01 ≦ x ≦ 0.08, higher brightness (InBO ₃ :
It exhibits a light emission of 1.10 times that of a Tb phosphor.

Note Figure 2 is a graph showing the relation between x value and the luminance of the electron beam excitation of a _{(In 1-x-y Al} x Tb y) BO 3 phosphor, but with terbium activator has changed Also in this case, it was confirmed that the relationship between the x value and the emission luminance had the same tendency as in FIG.

The terbium activation amount, that is, the y value in the phosphor of the present invention is suitably in the range of 0.0005 ≦ y ≦ 0.1. If the y value is out of this range, the emission brightness is significantly lowered, which is not preferable. A more preferable y value range is 0.001 ≦ y ≦ 0.
The range is 05.

Above As mentioned, phosphor of the present invention under an electron beam excitation (InBO _3: Tb) and show good green emission of the same color purity, especially under electron beam excitation (InBO _3: Tb) firefly It emits light with a higher brightness than that of light-emitting materials, and has increased its utility value as a green-emitting component phosphor for display tubes, color televisions, projection tubes, low-speed electron beams, and fluorescent display tubes. It is a thing.

Hereinafter, the present invention will be specifically described with reference to examples.

Example 1 indium oxide (In ₂ O ₃₎ 131.17g of aluminum oxide (Al ₂ O ₃₎ 2.55g of terbium oxide (Tb ₄ O ₇₎ 0.94g boric acid (H ₃ BO ₃₎ 74.20g each firefly Water was added to the raw material for the phosphor to form a paste, which was mixed well. The obtained mixture was dried, and after adding 2.1 g of lithium phosphate LiPO ₄ 1 / 2H ₂ in a mortar and mixing them well, the mixture was filled in an alumina crucible and calcined in air at a temperature of 500 ° C. for 2 hours. After the fired product was pulverized, it was refired under the same conditions. The obtained calcined product was pulverized, then filled in an alumina crucible again, and calcined in air at a temperature of 1250 ° C. for 2 hours. After firing, the fired product was crushed, washed several times at high temperature, dried and sieved. In this way (In
_{A 0.945} Al _0.05 TB _0.005 ) BO ₃ phosphor was obtained. This phosphor emits light under electron beam excitation. The emission spectrum is shown in FIG. The emission brightness of the green emission under electron beam excitation was 10% higher than that of the (In _0.995 Tb _0.005 ) BO ₃ phosphor.

Example 2 Indium oxide 134.22 g Aluminum oxide 1.53 g Terbium oxide 0.56 g Boron oxide 41.77 g Sodium chloride 2.1 g The fluorescent material and the flux were thoroughly mixed by a ball mill, and then air filled in a quartz crucible. Firing at a temperature of 1280 ° C. for 2 hours. After firing, the fired product was crushed, washed several times with warm water, dried and sieved. Thus, (In _0.967 Al _0.03 Tb _0.003 ) BO ₃ phosphor was obtained. This phosphor emits light under electron beam excitation. The emission spectrum is shown in FIG. The emission brightness of this green emission under electron beam excitation is 9 than that of the (In _0.997 Tb _0.003 ) BO ₃ phosphor.
% Was also high.

[Brief description of drawings]

FIG. 1 shows the fluorescence spectrum of the phosphor of the present invention. FIG. 2 is a graph showing the relationship between the x value and the emission luminance of the phosphor of the present invention under electron beam excitation.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Fushiki 1060 Narita, Odawara-shi, Kanagawa Kasei Optonix Co., Ltd.Odawara factory (72) Inventor Anichi Morita 3300 Hayano, Mobara-shi, Chiba Hitachi, Ltd. Mobara factory (72) Inventor Shuji Matsukii 1-280 Higashi Koigakubo, Kokubunji City, Tokyo Inside Central Research Laboratory, Hitachi, Ltd.

Claims (2)

[Claims] 1. An indium borate-based Tb characterized in that a part of indium is replaced with aluminum in an amount of 0.1 mol or less.
Activated phosphor. 2. A part of indium is aluminum and 0.00
The indium borate-based Tb-activated phosphor according to claim (1), which is substituted in the range of 1 to 0.008 mol.