KR100669372B1 - A preparation method of green emitting phosphor for vuvvacuum ultraviolet excited light emitting device - Google Patents

Abstract

The present invention relates to a method of manufacturing a green phosphor for a light emitting device using vacuum ultraviolet as an excitation source, and more particularly, a) mixing zinc oxide, silicon oxide, and manganese compound; And b) heat-treating the mixture using energy of microwaves. The present invention relates to a method of manufacturing a green phosphor for a light emitting device using vacuum ultraviolet radiation as an excitation source.

According to the method of manufacturing the green phosphor of the present invention, a Zn ₂ SiO ₄ : Mn green phosphor having high luminance, low process degradation, and a long lifetime can be produced by a low-temperature reaction, and the phosphor prepared by the above method has high luminous efficiency. Not only is it excellent and resistant to process deterioration, it is possible to prevent deterioration of the phosphor due to prolonged VUV irradiation, which has the advantage of maintaining the performance of the panel for a long time.

Vacuum ultraviolet ray, green phosphor, microwave, plasma display panel

Description

A manufacturing method of a green phosphor for a light emitting device using a vacuum ultraviolet ray as an excitation source {A PREPARATION METHOD OF GREEN EMITTING PHOSPHOR FOR VUV (VACUUM ULTRAVIOLET) EXCITED LIGHT EMITTING DEVICE}

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view of a microwave furnace apparatus used for producing a green phosphor of the present invention.

2 is an X-ray diffraction diagram of the green phosphor powder prepared in Example 1 and Comparative Example 1. FIG.

3 is a fluorescence (PL) emission spectrum of the green phosphor powder prepared by Example 1 and Comparative Example 1.

Figure 4 is a graph measuring the afterglow time of the green phosphor powder prepared in Example 1 and Comparative Example 1.

[Industrial use]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a green phosphor for a light emitting element using vacuum ultraviolet as an excitation source, and more particularly, to a method for manufacturing a Zn ₂ SiO ₄ : Mn green phosphor.

[Private Technology]

Fluorescent display panels, particularly plasma display panels, among the light emitting devices which use vacuum ultraviolet rays as excitation sources, are displays using light emission by ultraviolet rays generated by discharge of a mixed gas of Ne and Xe enclosed between glass substrates. . In this case, each phosphor generates visible light by resonance emission light (147 nm vacuum ultraviolet ray) of Xe ions. Phosphors used in plasma display panels have been studied to improve the phosphor materials used in phosphor application products such as CRT phosphors and fluorescent lamps, which have been used since the early stages of plasma display panel development. In order for a phosphor to be used in a plasma display panel, it must be excellent in luminescence brightness, luminous efficiency and color purity, have a short afterglow time, and in particular, do not cause deterioration of the phosphor by heat or ultraviolet rays.

At present, Zn ₂ SiO ₄ : Mn is mainly used as a green phosphor for plasma display panels. Zn ₂ SiO ₄ : Mn has excellent light emission luminance, but has a relatively long afterglow time and a rapid emission saturation with respect to vacuum ultraviolet rays compared to blue and red phosphors used in plasma display panels. In addition, since the dielectric constant is higher than that of the blue or red phosphors, there is a fatal disadvantage that the discharge start voltage is increased when the plasma display panel is driven. In order to solve this drawback, research on coating of Zn ₂ SiO ₄ : Mn phosphor, synthesizing new phosphor, improvement of manufacturing process, and the like is required. .

The present invention is to solve the above problems, an object of the present invention is to provide a method for producing a Zn ₂ SiO ₄ : Mn green phosphor having a high brightness, low process degradation and a long life by a low-temperature reaction will be.

The present invention to achieve the above object, a) mixing the zinc oxide, silicon oxide, and manganese compound; And b) heat-treating the mixture using microwave energy. The method provides a method of manufacturing a green phosphor for a light emitting device using vacuum ultraviolet radiation as an excitation source.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a method for producing a green phosphor for a device using a vacuum ultraviolet (VUV: Vacuum Ultraviolet) as an excitation source, wherein the green phosphor of the present invention is a green phosphor represented by the following Chemical Formula 1, wherein the green phosphor is formed of Xe gas. When excited by ultraviolet rays of 147 nm and 173 nm emitted from the plasma, a green emission band of 530 nm appears.

[Formula 1]

Zn ₂ SiO ₄ : Mn

Among the raw materials used to manufacture the green phosphor, ZnO is preferably used for the zinc oxide, and SiO ₂ is preferably used for the silicon oxide. In addition, it is preferable to use MnCO ₃ , MnO, MnF ₂ , Mn (NO ₃ ) ₂ , or MnCl ₂ as the manganese compound.

The composition of the raw material is preferably mixed in the ratio of the following formula (1).

[Formula 1]

xZnO + ySiO _2: z mol% Mn ⁺²

However, 1.5≤x / y≤2 and 0≤z≤15.

The raw material is uniformly mixed with such a composition, and then the mixture is subjected to a heat treatment process. At this time, the heat treatment process does not use an electric furnace which is a conventional heat source, and uses microwave energy as a heat source.

1 is a schematic cross-sectional view of a microwave furnace apparatus 1 used in the manufacture of the green phosphor of the present invention.

Referring to FIG. 1, the microwave furnace apparatus includes a crucible 11 into which fuel material is injected, a thermometer 13 installed through a center of the crucible lid 12 to measure the temperature in the crucible, and the crucible of the crucible. A pre-heater 14 formed to surround the outside, a heat insulating material 15 formed to surround the outside of the preheater, and a quartz chamber 16 formed to surround the outside of the heat insulating material, The quartz chamber is located in a multimode cavity 17. The microwave wave furnace apparatus also includes a microwave generator (not shown) and a mode stirrer (not shown) for uniformizing the microwaves.

In the microwave furnace apparatus used for manufacturing the green phosphor of the present invention, the crucible 11 is preferably made of alumina, and the preheater 14 is preferably a silicon carbide block.

The microwave generated by the microwave generator passes through the crystal chamber 16 and directly heats the raw material contained in the crucible 11. At this time, nitrogen gas or a mixture gas of nitrogen gas and hydrogen gas, which provides a reducing atmosphere, is introduced into the crystal chamber.

Microwave refers to radio waves from 1 mm to 1 m in wavelength. Generally, microwaves having a frequency of 300 to 3,000 MHz are called ultrahigh frequencies (UHF), and microwaves having a frequency of 3 to 300 GHz are microwaves. It is called (SHF: superhigh frequency). Microwaves penetrate air, glass, paper, and the like, are reflected by metal, and are easily absorbed by food and water.

Therefore, in the case of using an electric furnace, which is a conventional heat source, the mixture is not heated evenly, and thus, the process time is long, and high temperature is required. However, when the microwave energy of the present invention is used, heat is not generated in the raw material mixture itself. Since it occurs, it is heated uniformly, there is an advantage that the green phosphor can be produced in a short time at a low temperature.

In the present invention, the better the use of high frequency microwave energy, it is preferable to use the energy of the microwave having a microwave frequency of 900 MHz to 30 GHz, including 915 MHz, 2.45, It is more preferred to use microwave energy having an Industrial, Scientific, Medical (ISM) microwave frequency of 5.8, 18, 28, 30 GHz.

At this time, the heat treatment temperature is preferably to be 950 to 1150 ℃. When the heat treatment temperature is less than 950 ° C., the reaction between zinc oxide and silicon oxide does not sufficiently occur, and when the heat treatment temperature is higher than 1150 ° C., particles of the phosphor to be manufactured may become large and coating characteristics may deteriorate. The heat treatment is preferably performed for 3 hours or less, preferably 30 minutes to 1 hour.

The heat treatment is performed under a reducing atmosphere, and in order to create such a reducing atmosphere, nitrogen gas or a mixed gas of nitrogen gas and hydrogen gas is flowed out. At this time, the ratio of the nitrogen and hydrogen is preferably a volume ratio of 100: 0 to 90:10.

The manufacturing method of the green phosphor of the present invention has the advantage that the synthesis temperature is lower and the synthesis time is shorter than the conventional method based on the electric heat source. In addition, the green phosphor manufactured by the above method has improved crystallinity, small size, and optimized surface composition, particle size and shape of the phosphor powder, so that Mn ⁺² can be uniformly distributed when forming a phosphor film. The amount of Mn ⁺² is reduced, and optical characteristics such as luminance, color purity, discharge characteristics, and afterglow time are maximized.

The green phosphor manufactured by the manufacturing method of the present invention may be used in a light emitting device using vacuum ultraviolet radiation as an excitation source, and may be preferably used in a flat panel display, more preferably, a plasma display panel (PDP). Since the deterioration of the phosphor due to the long-term vacuum ultraviolet irradiation can be prevented, the performance of the panel can be maintained for a long time.

 Hereinafter, preferred embodiments of the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

Example 1

ZnO and SiO ₂ were added to the mixer in a molar ratio of 2: 1, and MnCO ₃ was added to include 11 mol% of Mn ⁺² in the final green phosphor, followed by uniform mixing. The mixture was placed in the alumina crucible 11 of FIG. 1, and heat-treated at a temperature of 1060 ° C. for 1 hour using a microwave having a wavelength of 2.45 GHz to prepare a Zn ₂ SiO ₄ : Mn green phosphor.

The heat treatment process was performed while flowing a mixed gas in which nitrogen gas and hydrogen gas were mixed at a volume ratio of 95: 5 into the crystal chamber 16.

The prepared phosphor powder, glass ball and distilled water were mixed at a ratio of 1: 4: 2, milled at 150 rpm for 1 hour, and then the powder was put back into an acid solution (1.5 ml of 37% HCl / 1L pure water). The powder was washed for about 1 hour to prepare a phosphor powder having a particle diameter of 2 μm or less.

Comparative Example 1

ZnO and SiO ₂ were added to the mixer in a molar ratio of 2: 1, and MnCO ₃ was added to include 11 mol% of Mn ⁺² in the final green phosphor, followed by uniform mixing. The mixture was placed in an electric furnace and heat-treated at a temperature of 1300 ° C. for 3 hours to prepare green phosphor powder in the same manner as in Example 1 except that Zn ₂ SiO ₄ : Mn green phosphor was prepared.

The X-ray diffraction patterns of the green phosphor powders prepared by Example 1 and Comparative Example 1 were examined, and the results are shown in FIG. 2, and the fluorescence (PL) emission spectrum measured by excitation light at 147 nm is shown in FIG. 3. Indicated. As shown in FIG. 3, the x and y coordinates of the green phosphor of Example 1 and the green phosphor of Comparative Example 1 are the same, but the luminance of the green phosphor of Example 1 is higher.

Afterglow graphs of the green phosphor powders prepared by Example 1 and Comparative Example 1 are shown in FIG. 4. If the amount of Mn ^{+ 2 in} the green phosphor powder is increased, the afterimage time is shortened. Accordingly, as shown in FIG. 4, the green phosphor of Example 1 using microwave energy as a heat source has a smaller amount of Mn ^{+ 2} added to obtain the same afterimage time as compared to the green phosphor of Comparative Example 1 using an electric furnace as a heat source. You can see that.

In the method of manufacturing the green phosphor of the present invention, Zn ₂ SiO ₄ : Mn green phosphor to which Mn ⁺² is added, which has high luminance, low process deterioration and long life, can be produced at low temperature, low temperature, and short time. The manufactured phosphor is excellent in luminous efficiency and strong in process deterioration, and can prevent deterioration of the phosphor due to prolonged VUV irradiation, thereby maintaining the performance of the panel for a long time.

Claims (8)

a) mixing zinc oxide, silicon oxide, and manganese compound; And b) heat-treating the mixture using energy of microwaves having a frequency of 900 MHz to 30 GHz A method of manufacturing a green phosphor for a light emitting element comprising a vacuum ultraviolet ray as an excitation source. delete The method of manufacturing a green phosphor for a light emitting element according to claim 1, wherein the microwaves have a frequency of 915 MHz, 2.45 GHz, 5.8 GHz, 18 GHz, 28 GHz, or 30 GHz. The method of claim 1, wherein the heat treatment step is carried out for 3 hours or less using microwave energy at a temperature of 950 to 1150 ℃ in the presence of nitrogen gas or a mixed gas of nitrogen and hydrogen, vacuum ultraviolet to excitation source Method of manufacturing a green phosphor for a light emitting device. The method of manufacturing a green phosphor for a light emitting device according to claim 4, wherein the heat treatment is performed for 30 minutes to 1 hour. The method of manufacturing a green phosphor for a light emitting device according to claim 4, wherein nitrogen and hydrogen gas in the heat treatment step are in a ratio of 100: 0 to 90:10. The method of claim 1, wherein the zinc oxide is ZnO, the silicon oxide is SiO ₂ , and the manganese compound is selected from the group consisting of MnCO ₃ , MnO, MnF ₂ , Mn (NO ₃ ) ₂ , and MnCl ₂ . The manufacturing method of the green fluorescent substance for light emitting elements which uses 1 or more types of vacuum ultraviolet rays as an excitation source. The method of manufacturing a green phosphor for a light emitting element according to claim 7, wherein the zinc oxide, silicon oxide, and manganese compound are mixed at a ratio of the following Formula 1. [Formula 1] xZnO + ySiO _2: z mol% Mn ⁺² However, 1.5≤x / y≤2 and 0≤z≤15.

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