KR930003701B1 - Production of green luminous fluorescent material - Google Patents

Abstract

The green light emitting fluorescent material of ZnO:Zn is manufactured by (a) mixing 100 wt. pts. of a high purity zinc oxide (ZnO, 99.99 %) with 5-100 PPM of an aq. soln. of Zn(NO3)2 obtd. by dissolving Zn powder into HNO3, (b) drying the mixture in the dryer, and (c) firing the dryed ZnO in a quartz or alumina pot under the reduction atmosphere of 5 % H2 + 95 % N2 gas at 800-1000 deg.C for 0.5-2 hr. The fluorescent material has an excellent emitting luminance and luminous characteristic.

Description

Manufacturing method of green light emitting phosphor

1 is a graph showing the emission intensity according to the addition amount of zinc (Zn) in the green light emitting phosphor of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a green light emitting phosphor, and in particular, to a method for manufacturing a green light emitting phosphor having excellent emission luminance characteristics and luminance saturation characteristics used in low speed electron excitation, for example, a fluorescent display tube, which emit light at an acceleration voltage of 100 V or less. It is about.

In general, the green light emitting phosphor for low-speed electron beam excitation that emits light at an acceleration voltage of 100V or less should have the following characteristics.

(1) To be electrically conductive to prevent charging by primary electron beam,

(2) the emission start voltage is essentially low;

(3) High luminous efficiency and no luminance saturation

(4) Be stable to the environment during the manufacturing process of fluorescent display tubes;

(5) Long lifespan.

Recently, low-speed electron beam green light-emitting phosphors satisfying the above conditions have been demanded in accordance with the increase in their field of use. The low-speed electron beam green light emitting phosphor that satisfies the above conditions to some extent includes sulfide phosphors and zinc oxide phosphors, but zinc oxide phosphors are superior in light emission luminance and lifetime than sulfide phosphors.

In general, a method for producing a zinc oxide phosphor represented by ZnO: Zn is calcination of zinc oxide (ZnO) in a reducing atmosphere or in the air by adding a small amount of zinc compound such as zinc emulsion (ZnS) to zinc oxide (ZnO). It is the most common manufacturing method.

In addition, the zinc oxide phosphor prepared in this way is a self-resilient phosphor with zinc oxide as a parent, and thus becomes a phosphor by itself. Degrades.

In addition, when the phosphor is manufactured by a conventional method, zinc (Zn), which is a self-activating agent, does not normally penetrate into the parent ZnO, and thus light emitting only a portion of the low speed electron beam is often performed.

In such a case, the light emission intensity and luminance saturation characteristics are deteriorated.

Disclosure of Invention It is an object of the present invention to provide a method of manufacturing a green light-emitting phosphor which has excellent light emission intensity and luminance saturation characteristics by improving the conventional phosphor manufacturing method in view of the above problems.

In order to achieve the above object, the present invention is characterized in that in the raw material mixing method for the preparation of ZnO: Zn phosphor, ZnO powder is added by adding zinc ions (Zn ⁺² ) as an activator, wet mixed and dried to obtain a raw material mixture. There is this.

In the above production method, high purity zinc oxide is used as a raw material, and zinc oxide is placed in a dish-type heat resistant container such as quartz or alumina for 30 minutes at 800 to 1000 ° C. under a reducing atmosphere of 5% H ₂ + 95% N ₂ gas. Firing for a time to obtain a zinc oxide phosphor.

However, since the phosphor is calcined in a reducing atmosphere, zinc ions (Zn ⁺² ) are not volatilized from the parent ZnO. As a result, it did not penetrate into the mother and partially emits light, thereby failing to obtain a phosphor having high emission intensity.

Hereinafter, a method of manufacturing the phosphor according to the present invention will be described in detail.

First, high purity zinc oxide (99.99%) is prepared. The Zn powder is dissolved in nitric acid (HNO ₃ ) to prepare an aqueous solution of Zn (NO ₃ ) ₂ .

To 100 parts by weight of the prepared zinc oxide (purity: 99.99%) powder is added by Zn (NO ₃ ) ₂ aqueous solution of 5 to 100PPM and wet-mixed, followed by drying sufficiently with a drier.

The zinc oxide dried in this way is put in a dish-type heat-resistant container such as quartz or alumina in a reducing atmosphere of 5% H ₂ + 95% N ₂ gas (flow rate: 10 ml / min) at 800 to 1000 ° C. for 30 minutes to 2 hours. It was calcined during to obtain the green light emitting phosphor of the present invention.

Hereinafter, another preferred embodiment of the present invention will be described in detail.

Example 1

Prepare 100 g of 9n% purity ZnO. Then, the Zn powder was dissolved in nitric acid to prepare an aqueous 1000 ml zinc nitrate solution of 1000 PPM.

10 ml of the zinc aqueous solution is added to the zinc oxide powder prepared above (Zn ^{+2 of} 10PPM). After wet mixing in this way, it is dried sufficiently with a dryer.

The dried zinc oxide was put in a plate-shaped alumina and calcined at 900 ° C. for 1 hour under a reducing atmosphere of 5% H ₂ + 95% N ₂ gas (flow rate: 10 ml / min) to obtain a green light-emitting phosphor of the present invention. In the phosphor of the present invention, the luminescence intensity is improved by about 10% compared to the conventional phosphor without Zn ions.

Example 2

Perform the same method as in Example 1, but add 20 ml of an aqueous zinc solution to the zinc oxide powder (Zn ^{+2 of} 20PPM). In the obtained phosphor of the present invention, the emission intensity was improved by about 20% compared with the conventional phosphor without Zn ions.

Example 3

Perform the same method as in Example 1, but add 30 ml of an aqueous zinc solution to the zinc oxide powder (Zn ^{+2 of} 30PPM). In the obtained phosphor of the present invention, the luminescence intensity was improved by about 15% compared with the conventional phosphor without addition of Zn ions. FIG. 1 is a graph showing the luminescence intensity according to the amount of zinc added in the green luminescent phosphor of the present invention. The luminescence intensity of the green luminescent phosphor of the present invention is improved by about 20% compared to the phosphor in which the Zn ion is not added.

In addition, the emission intensity of the green light emitting phosphor of the present invention was highest when Zn ions were added to 20PPM, and when more Zn ions were added, the phenomenon appeared to decrease. As described above, according to the present invention, a ZnO: Zn green light emitting phosphor obtained by adding Zn ions as an activator in the raw material mixing method in the preparation of ZnO: Zn green light emitting phosphor, the whole of the light is uniformly emitted instead of partial light emission. In addition, there was no luminance saturation with high luminous efficiency, long lifetime, and excellent luminous luminance and luminance saturation characteristics.

Claims (2)

In the raw material mixing method in the production of ZnO: Zn phosphor, the method of producing a green light emitting phosphor, characterized in that the ZnO powder as a parent to add zinc ions (Zn ⁺² ) as an activator, and then wet mixed and dried to obtain a raw material mixture. . The method of claim 1, wherein the zinc ion added based on the ZnO is 5 to 100PPM.

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