KR20060079989A - Phosphors for vacuum ultraviolet excitation, process for preparing the same, and display device using the same - Google Patents

Abstract

The vacuum ultraviolet excitation phosphor according to the present invention has excellent color purity and brightness compared to conventional phosphors, and also improves plasma sputtering characteristics, and thus, when used in display devices such as PDPs, CRTs, and lamps, the luminance maintenance factor (life characteristic) is improved. It is possible to improve.

The phosphor contains at least one selected from the group consisting of Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Mn as an activator in the compound of Formula 1 below.

<Formula 1>

M ₁ M ₂ M ₃ O ₈

In the formula, M ₁ represents one or more selected from the group consisting of Li, Na and K; M ₂ represents at least one member selected from the group consisting of Ca, Sr, Mg and Zn; M ₃ represents two or more selected from the group consisting of Group 13 elements and Group 14 elements.

Description

Phosphors for vacuum ultraviolet excitation, process for preparing the same, and display device using the same}

Figure 1 shows the excitation spectrum results of the parent during vacuum ultraviolet irradiation of Zn ₂ SiO ₄ : Mn (P1), a commercial phosphor in the range of 120nm to 300nm and the phosphor according to Example 1 of the present invention.

Figure 2 shows the results of the luminance measurement of the phosphor according to Example 1 of the present invention and Zn ₂ SiO ₄ : Mn (P1) and a commercial phosphor when irradiating vacuum ultraviolet light using an excimer 146nm lamp.

Figure 3 shows the life test results compared to the phosphor and the commercial phosphor Zn ₂ SiO ₄ : Mn (P1) according to Example 1 of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum ultraviolet excitation phosphor, a method of manufacturing the same, and a display device employing the same. More specifically, when used in a display device using vacuum ultraviolet radiation as an excitation source, the color purity and luminance are excellent and the lifespan characteristics are improved. A vacuum ultraviolet excitation phosphor, a manufacturing method thereof, and a display element employing the same.

In general, a fluorescent display, particularly a plasma display panel (PDP), is a display 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 light) of Xe ions.

The phosphor used in the conventional PDP has been studied to improve the fluorescent material that has been used in phosphor application products such as CRT phosphors and fluorescent lamps that have been used since the beginning of PDP development. In order for a phosphor to be used in a PDP, it should basically be excellent in luminescence brightness, luminous efficiency and color purity, afterglow time should be short, and in particular, the phosphor should not be degraded by heat or ultraviolet rays.

Green phosphors commonly used in PDPs are most commonly used as Zn ₂ SiO ₄ : Mn (hereinafter referred to as P1). P1 has a slightly lower color purity with a CIE x color coordinate of about 0.25. In addition, in P1, as the content of Mn used as the activator is increased, the decay time is reduced but the luminance is also reduced at the display device application level.

In particular, since the luminance of the green phosphor contributes the most to the overall luminance in the PDP, it is very important to increase the luminance of the green phosphor. There is a need for phosphors with increased brightness.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a vacuum ultraviolet excitation phosphor that exhibits high luminance and color purity and has improved lifetime characteristics.

Another object of the present invention is to provide a method for manufacturing the vacuum ultraviolet excitation phosphor.

Another object of the present invention is to provide a display device employing the vacuum ultraviolet excitation phosphor.

The present invention to achieve the above technical problem,

Phosphor for vacuum ultraviolet excitation containing at least one selected from the group consisting of Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Mn as an activator Provides:

<Formula 1>

M ₁ M ₂ M ₃ O ₈

Food,

M ₁ represents at least one member selected from the group consisting of Li, Na and K;

M ₂ represents at least one member selected from the group consisting of Ca, Sr, Mg and Zn;

M ₃ represents two or more selected from the group consisting of Group 13 elements and Group 14 elements.

According to one aspect of the invention, the Group 14 element represents Si, Ge, Sn or Pb, and the Group 13 element represents B, Al or Ga.

According to one embodiment of the present invention, the compound of Formula 1 is preferably a compound of Formula 2:

<Formula 2>

Li ₂ Zn (Ge, X) _y O ₈ : zMn

In the above formula,

X represents B, Al or Ga, y represents a number from 3 to 4 and z represents a number from 0.01 to 0.1.

The present invention to achieve the above other technical problem,

Mixing each of the component materials in a predetermined ratio;

Applying primary firing in an air atmosphere; And

It provides a method for producing a vacuum ultraviolet excitation phosphor, comprising the step of subjecting the secondary firing in an atmosphere of nitrogen gas containing less than 5% hydrogen gas.

In order to achieve the above another technical problem, a display device employing the vacuum ultraviolet excitation phosphor is provided.

The present invention will be described in more detail below.

The present invention provides a vacuum ultraviolet excitation phosphor that exhibits high luminance and high color purity green light emission in a vacuum ultraviolet excitation, a method for manufacturing the same, and a display device employing the same. As the activator, one or more selected from the group consisting of Ce, Pr, Nd, pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Mn:

<Formula 1>

M ₁ M ₂ M ₃ O ₈

Wherein M ₁ represents at least one member selected from the group consisting of Li, Na, and K, M ₂ represents at least one member selected from the group consisting of Ca, Sr, Mg, and Zn, and M ₃ represents a Group 13 element And two or more selected from the group consisting of Group 14 elements.

When the conventional green phosphor increases the content of the activator, the afterglow time is reduced when applied to the display device, but the luminance is reduced. However, the phosphor according to the present invention decreases the afterglow time when the content of the activator is increased. In addition, the luminance reduction is improved.

In the compound of Formula 1, M ₃ refers to two or more compounds selected from the group consisting of Group 13 elements and Group 14 elements, and the Group 14 elements include, for example, Si, Ge, Sn or Pb. Ge is particularly preferred. B, Al, or Ga is mentioned as said group 13 element. The content of such M ₃ is 1 to 10 mol%, preferably 3 to 4 mol% with respect to 1 mol of M ₂ . When the content of M ₃ exceeds 10 mol%, there is a problem such as color purity decrease due to the red shift of the emission spectrum, and when it is less than 1 mol%, there is no effect due to the addition, which is not preferable.

In the compound of Formula 1, M ₁ represents at least one member selected from the group consisting of Li, Na, and Ka, and particularly preferably Li. The content of such M ₁ is preferably 1.8 to 2.2 mol% based on 1 mol of M ₂ . If the content of M ₁ exceeds 2.2 mol%, there is a problem such as lowering of the luminance of light emission, and if it is less than 1.8 mol%, there is a problem of lowering of luminance of light emission, which is not preferable.

As the activator in the compound of Formula 1, one or more selected from the group consisting of Ce, Pr, Nd, pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Mn may be used, and Mn is particularly desirable. The content of such an activator is preferably used 1 to 10 mol% based on 1 mol of M ₂ . If the content is more than 10 mol%, there is a problem such as decrease in brightness, if less than 1 mol% there is a problem that the afterglow time is long, which is not preferable.

As the compound of Formula 1, a compound of Formula 2 is preferable.

<Formula 2>

Li ₂ Zn (Ge, X) _y O ₈ : zMn

In the formula, X represents B, Al or Ga, y represents a number from 3 to 4, and z represents a number from 0.01 to 0.1.

In the phosphor according to Chemical Formula 2, each molar ratio of Ge and X is preferably 1: 0.01 to 0.1, which is not preferable because there is no effect due to the red shift or addition of the emission spectrum when it is outside the above range.

In addition, the total molar ratio of Ge and X is preferably 3 to 4 moles with respect to 1 mole of Zn, and when the total molar ratio is less than 3 moles, there is a problem such as deterioration of luminance. There is a problem and is undesirable. Similarly, since the content of the activator has a ratio of 0.01 to 0.1 mole with respect to 1 mole of Zn, when the content of the activator is less than 0.01 mole, there is a problem that the afterglow time is long, and when the content of the activator exceeds 0.1 mole, the luminance It is not preferable because there is a problem such as deterioration.

Referring to the manufacturing method of the vacuum ultraviolet excitation phosphor according to the present invention described above is as follows.

The vacuum ultraviolet excitation phosphor according to the present invention comprises the steps of mixing the component materials in a predetermined ratio, respectively, applying primary firing under an air atmosphere, and applying secondary firing under a nitrogen gas atmosphere containing hydrogen gas.

The primary firing is preferably carried out in an air atmosphere. At this time, the firing temperature is preferably 850 to 900 ° C. When the firing temperature exceeds 900 ° C, there is a problem that melting occurs, and the firing temperature is 850. When it is less than ° C, there is a problem that the particle size formation becomes insufficient, which is not preferable. In addition, since the primary firing time is preferably 2 to 4 hours, when the firing time exceeds 4 hours, there is a problem of excessive particle size, and when the firing time is less than 2 hours, there is a problem of insufficient particle size formation. Not desirable

The secondary firing is preferably performed in a nitrogen gas atmosphere containing hydrogen gas for the reason that reduction of Mn ³⁺ to Mn ²⁺ occurs, and the hydrogen gas is less than 5% with respect to the total content of nitrogen gas, preferably It is recommended to use in proportion of 1% to 2% content. At this time, the secondary firing temperature is preferably 900 to 950 ° C., and when the firing temperature exceeds 950 ° C., there is a problem in that melting occurs, and when the firing temperature is less than 900 ° C., the problem of insufficient particle size formation occurs. It is not desirable. In addition, the second firing time is preferably 2 to 2.5 hours. When the firing time exceeds 2.5 hours, there is a problem such as a decrease in brightness. When the firing time is less than 2 hours, the luminance decreases due to insufficient reduction. It is not preferable because of the same problem.

The phosphor that has passed through the above-described firing process may further include a milling and drying process, and such a process may use any method used in a conventional phosphor manufacturing process without any limitation. The phosphor powder obtained when the milling and drying process is performed has a uniform size of about 3 to 7 microns, preferably about 5 microns, on average.

In addition, in the raw material mixing step, a solvent may be used to make the mixing of the raw materials easier, and examples of the solvent that can be used include water, acetone, and alcohol. The amount of these solvents can be used without any limitation in the amount used in the usual phosphor manufacturing process.

The molar ratio of the raw materials in the manufacturing process based on 1 mol M ₂ , M ₁ may be 1.8 to 2.2 mol%, M ₃ is 3 to 4 mol%, activator 0.01 to 0.1 mol% may be used.

In the case of M ₁ , each metal component used as the raw material is preferably in the form of a carbonate, M ₂ is in the form of an oxide, M ₃ is in the form of an oxide, and an activator is preferably in the form of a carbonate.

The vacuum ultraviolet excitation phosphor obtained through such a manufacturing method has excellent color purity and luminance and improved lifetime characteristics when used in a display device using vacuum ultraviolet radiation as an excitation source. Therefore, for example, it can be usefully used for PDP, CRT, lamps and the like.

Although an Example is given to the following and this invention is demonstrated to it in more detail, this invention is not limited to this.

Example 1

2 mol of Li ₂ CO ₃ , 1 mol of ZnO, 3.3 mol of GeO ₂ , 0.04 mol of Al ₂ O ₃ , and 0.05 mol of MnCO ₃ were mixed and mixed. Primary firing was carried out by holding at 900 ° C. for 2 hours in an air atmosphere, and then firing was carried out at 950 degrees for 2 hours under an atmosphere of nitrogen gas containing 2% hydrogen gas to prepare a desired phosphor. .

Example 2

Li ₂ CO _{3 2} mol, 1 mol of ZnO, GeO ₂ and Ga ₂ O ₃ 0.03 mole 3.5 mole, and MnCO ₃ blended with 0.07 mol, was mixed. Primary firing was carried out by holding at 900 ° C. for 2 hours in an air atmosphere, followed by secondary firing at 950 ° C. for 2 hours under an atmosphere of nitrogen gas containing 1% hydrogen gas, to prepare a desired phosphor. .

Experimental Example 1: Luminance Measurement

The luminance of the phosphor obtained in Example 1 was irradiated with vacuum ultraviolet rays using an excimer 146 nm lamp in a vacuum chamber of 6.7 Pa (5 × 10 ⁻² torr) or less, and the luminance of Zn ₂ SiO ₄ : Mn, which is a commercial phosphor, was 100. As shown in FIG. 2 in comparison. As can be seen in Figure 2, in the case of the phosphor prepared in Example 1 according to the present invention showed a high luminance of 102 to 105.

Experimental Example 2: thermal degradation test and life test

In the heat treatment conditions, the paste and the phosphor were mixed in an appropriate ratio as applied to the display device, and left for 1 hour to exhaust the organic material inside the paste at a temperature of about 500 degrees. The life test is conducted for a short time in a slightly excessive condition than the inside of the PDP display element to see that 90% or more of the plasma ions hit the phosphor surface and deteriorate. In particular, commercial phosphors are known to be very susceptible to such plasma sputtering. After heat treatment and life test, the brightness was more than 107% compared to the commercial Zn ₂ SiO ₄ : Mn. Thus, it can be seen that the phosphor is stable against heat treatment and ion sputtering which are indispensable for the PDP display element.

The vacuum ultraviolet excitation phosphor according to the present invention has excellent color purity and brightness compared to conventional phosphors, and also improves plasma sputtering characteristics, and thus, when used in display devices such as PDPs, CRTs, and lamps, the luminance maintenance factor (life characteristic) is improved. Since it is possible to improve, it can be usefully used for various display elements.

Claims (9)

Vacuum, characterized in that the compound of formula 1 contains at least one selected from the group consisting of Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Mn UV excitation phosphor: <Formula 1> M ₁ M ₂ M ₃ O ₈ Food, M ₁ represents at least one member selected from the group consisting of Li, Na and K; M ₂ represents at least one member selected from the group consisting of Ca, Sr, Mg and Zn; M ₃ represents two or more selected from the group consisting of Group 13 elements and Group 14 elements. The phosphor for vacuum ultraviolet excitation according to claim 1, wherein the Group 14 element represents Si, Ge, Sn, or Pb, and the Group 13 element represents B, Al, or Ga. The phosphor for vacuum ultraviolet excitation according to claim 1, wherein the content of M ₃ is 1 to 10 mol% based on 1 mol of M ₂ . The method of claim 1, wherein the content of the M ₁ fluorescent substance for vacuum ultraviolet ray-excited, characterized in that 1.8 to 2.2 mol% relative to 1 mol of M _2. The vacuum ultraviolet excitation phosphor according to claim 1, wherein the content of the activator is 0.01 to 0.1 mol% with respect to 1 mol of M ₁ . According to claim 1, wherein the compound of formula 1 is a vacuum ultraviolet excitation phosphor, characterized in that the compound of formula (2): <Formula 2> Li ₂ Zn (Ge, X) _y O ₈ : zMn In the above formula, X represents B, Al or Ga, y represents a number from 3 to 4 and z represents a number from 0.01 to 0.1. The vacuum ultraviolet excitation phosphor according to claim 6, wherein the molar ratio of Ge and X is 1: 0.01 to 0.1. Mixing each of the component materials in a predetermined ratio; Applying primary firing in an air atmosphere; And A method for producing a vacuum ultraviolet-excitation phosphor according to any one of claims 1 to 7, characterized in that the secondary firing is performed under an atmosphere of nitrogen gas containing less than 5% hydrogen gas. A display device comprising the vacuum ultraviolet excitation phosphor according to any one of claims 1 to 8.

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