JP2001172625A - Vacuum ultraviolet excitable fluorescent substance and light emitting device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fluorescent substance capable of exhibiting a high emission luminance under excitation with vacuum ultraviolet rays and to provide a high- quality light emitting device using the fluorescent substance. SOLUTION: This vacuum ultraviolet excitable fluorescent substance substantially represented by the general formula Ba1-aEuaMgAlbOcNd (wherein a, b, c and d are each a number satisfying 0.05<=a<=0.4; 8<=b<10; 11<=c<=17; and 0<d<=2). The vacuum ultraviolet excitable fluorescent substance comprises the fluorescent substance as a blue light emitting component. The light emitting device includes the vacuum excitable blue light emitting fluorescent substance or the vacuum ultraviolet excitable fluorescent substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum ultraviolet ray excited phosphor and a light emitting device using the same.

[0002]

2. Description of the Related Art In recent years, a light emitting device using vacuum ultraviolet light having a short wavelength such as 147 nm or 172 nm as an excitation source of a phosphor has been developed. For example, it is used as a light-emitting part of a plasma display panel (PDP), which is attracting attention as a large screen, thin, and digital display device capable of displaying various information with high precision and high definition, and as a backlight of an in-vehicle liquid crystal display. Xenon being used (X
e) and the like are rare gas discharge lamps and the like.

Heretofore, as a phosphor of such a light emitting device, a phosphor having relatively excellent emission characteristics by vacuum ultraviolet rays has been empirically selected from various phosphors conventionally known.

That is, for example, in a full-color PDP, (Y, Gd) BO ₃ : Eu phosphor and Zn ₂ SiO ₄ : Mn are used as red, green and blue light-emitting phosphors, respectively.
A phosphor, BaMgAl ₁₀ O ₁₇ : Eu phosphor, is used, and in a rare gas discharge lamp, a mixture of these phosphors is generally used. In addition, BaAl ₁₂ O ₁₉ : Mn phosphor and BaMg
Al ₁₄ O ₂₃ : Mn phosphors are also used.

[0005] However, these phosphors are originally
It may not have been developed for excitation of vacuum ultraviolet light, and thus did not always sufficiently satisfy characteristics such as luminance required for the light emitting device. Above all, the blue light-emitting phosphor has a lower luminance than the phosphors of other light emission colors such as green and red, which causes a decrease in luminance of the light-emitting device.

[0006]

As described above, the phosphor used in a light emitting device such as a PDP using vacuum ultraviolet light as an excitation source of the phosphor is not always satisfactory in characteristics. The blue phosphor has a lower luminance than phosphors of other emission colors such as green and red, and thus has a problem of lowering the luminance of the light emitting device. For this reason, there is a need for the development of a blue phosphor having a high luminous efficiency by vacuum ultraviolet rays and a phosphor containing such a blue phosphor, which enables higher luminance of a light emitting device using vacuum ultraviolet rays as an excitation source of the phosphor. ing.

SUMMARY OF THE INVENTION The present invention has been made to address such a problem, and a blue phosphor having high luminous efficiency by vacuum ultraviolet rays, a phosphor containing the same, and an increase in luminance using such a phosphor. It is an object of the present invention to provide an intended light emitting device.

[0008]

Means for Solving the Problems In order to achieve the above object, the present inventors have made various studies and found that a certain amount of nitrogen (N) was added to a certain divalent europium-activated aluminate phosphor. ), A blue phosphor with high luminous efficiency by vacuum ultraviolet rays can be obtained.

The present invention has been made based on such findings, and the vacuum ultraviolet ray-excited blue light-emitting phosphor of the present invention has the following general formula: Ba _{1 -a} Eu _a MgAl _b O _c N _d (where, a, b, c and d are 0.05 ≦ a ≦ 0.4,7 ≦ b <
10, 10 ≦ c <17, and 0 <d ≦ 2).

[0010] In the vacuum ultraviolet ray-excited blue light-emitting phosphor of the present invention, as described in claim 2,
It is desirable that d be a number satisfying 0 <d ≦ 1.

Further, the vacuum ultraviolet ray excited blue light emitting phosphor of the present invention has a wavelength of 140 to 180 in particular.
It is suitable as a vacuum ultraviolet ray excited blue light emitting phosphor that emits visible light upon irradiation with vacuum ultraviolet light of nm.

Next, the VUV-excited phosphor of the present invention comprises:
As described in claim 4, in a VUV-excited phosphor containing a blue light-emitting component, a green light-emitting component, and a red light-emitting component, the above-mentioned VUV-excited blue-light-emitting phosphor is included as the blue light-emitting component. And

The VUV-excited phosphor of the present invention is particularly suitable as a VUV-excited phosphor that emits visible light when irradiated with VUV light having a wavelength of 140 to 180 nm.

The vacuum ultraviolet ray excited blue light emitting phosphor of the present invention efficiently absorbs vacuum ultraviolet light and emits blue visible light with high efficiency. Further, the VUV-excited phosphor of the present invention contains a VUV-excited blue phosphor exhibiting high luminous efficiency with respect to such VUV as a blue light-emitting component. Therefore, by using these, it is possible to increase the luminance of a light emitting device using vacuum ultraviolet light as an excitation source.

That is, the light emitting device according to the present invention is characterized in claim 6.
As described above, the present invention is characterized by including the above-described vacuum ultraviolet ray excited blue light emitting phosphor of the present invention.

According to a seventh aspect of the present invention, there is provided a light emitting device including the above-described vacuum ultraviolet ray excited blue light emitting phosphor of the present invention, and a light source for irradiating the light emitting portion with vacuum ultraviolet light. It is characterized by having.

As a specific application example of the light emitting device of the present invention, as described in claim 8, the light emitting device of the present invention includes:
A plasma display device comprising a control unit for controlling light emission of the light emitting device is mentioned. Further, as a specific example of the light emitting device of the present invention, as described in claim 9, the vacuum ultraviolet excitation fluorescent light of the present invention is used. A fluorescent lamp includes a light emitting unit including a body and a light source that irradiates the light emitting unit with vacuum ultraviolet rays.

[0018]

Embodiments of the present invention will be described below.

The VUV-excited blue phosphor of the present invention have the general _{formula: Ba 1-a Eu a MgAl} b O c N d ... (1) ( wherein, a, b, c and d are 0.05 ≦ a ≦ 0.4, 7 ≦ b <
10, 10 ≦ c <17, and 0 <d ≦ 2).

A, b, c and d in the above formula (1)
The reason for limiting the value range of is as follows.

If the value of a indicating the content of europium (Eu) is less than 0.05, the concentration of the activator in the phosphor becomes low, the luminous efficiency decreases, and it is not possible to obtain sufficient luminance. Conversely, when the value of a exceeds 0.4, the luminance is significantly reduced due to concentration quenching and the like. The value of a is more preferably in the range of 0.05 to 0.3.

When the value of b indicating the content of aluminum (Al) is less than 7 or 10 or more, the brightness decreases. The value of b is more preferably in the range of 8 to 10.

The value of c indicating the content of oxygen atoms (O) is 10
If it is less than 17 or more than 17, the brightness is reduced. The value of c is more preferably in the range of 11-16.

The value of d indicating the content of nitrogen atoms (N) is
Of particular importance in the present invention. That is, the effect of increasing the luminous efficiency by vacuum ultraviolet rays and improving the luminance is mainly due to the inclusion of nitrogen. However, if the value of d exceeds 2, the brightness will conversely decrease. Therefore, in the present invention, the content is set in the range of 0 <d ≦ 2. More preferably, the value of d is in the range of 0.5 to 1.

Such a divalent europium activated phosphor efficiently absorbs vacuum ultraviolet light having a wavelength of about 140 to 180 nm. Therefore, when excited by such vacuum ultraviolet rays, blue light can be emitted efficiently.

The above-mentioned vacuum ultraviolet ray excited blue phosphor is produced, for example, as follows.

First, oxides of Ba _, Eu, Mg and Al, compounds such as hydroxides and carbonates which easily become oxides at high temperatures, and raw material powders of aluminum nitride were prepared as described in (1) above. Weigh a predetermined amount so that the composition of the formula,
These are sufficiently mixed with a flux such as AlF ₃ using a ball mill or the like.

Next, this raw material mixture is placed in a heat-resistant container such as an alumina crucible and fired in the atmosphere at a temperature of about 1400 to 1600 ° C. for about 3 to 5 hours (primary firing).

After the obtained fired product is pulverized and sieved,
Once again housed in a heat-resistant container such as an alumina crucible, place a reducing aid such as graphite on top of it, and calcine it at a temperature of about 1400 to 1600 ° C for about 3 to 5 hours under a reducing atmosphere such as nitrogen + hydrogen ( Secondary firing).

It should be noted that calcination in a reducing atmosphere may be repeated at least twice without using a flux.

Thereafter, the obtained fired product is dispersed, washed with water,
By performing processes such as drying and sieving as required, a desired blue-light-emitting vacuum ultraviolet-excited phosphor can be obtained.

In the present invention, a green light emitting component and a red light emitting component can be contained in the above-mentioned vacuum ultraviolet ray excited blue light emitting phosphor. Such a VUV-excited phosphor is applied to a three-wavelength band fluorescent lamp or the like. Here, the phosphor as the blue and green light emitting components is not particularly limited, but it is preferable to use a phosphor having excellent luminous efficiency by vacuum ultraviolet rays.

[0033] For example, as the green-emitting component, the general _{formula: Ba 1-x Mn x Al} 12 O 9 ... (2) ( wherein, x is the number a is satisfying a 0.1 ≦ x ≦ 0.4) substantially in It is preferable to use the barium aluminate phosphor represented.

The red light-emitting component is represented by the general formula: (Y _0.65 Gd _0.35 ) _1-y Eu _y BO ₃ (3) (where y is a number satisfying 0.05 ≦ y ≦ 0.2). It is preferred to use a substantially represented yttrium gadolinium borate phosphor.

Each of the above-mentioned green light-emitting phosphor and red light-emitting phosphor has excellent absorption efficiency of vacuum ultraviolet rays, and therefore can emit green light and red light efficiently when excited by vacuum ultraviolet rays.

As described above, the VUV-excited blue-emitting phosphor and the VUV-excited phosphor of the present invention have a wavelength of 140 nm.
It has excellent luminous efficiency with respect to vacuum ultraviolet rays of about 180 nm. Therefore, it is suitable as a phosphor used in a light emitting device using such a light source emitting vacuum ultraviolet rays.

The light-emitting device of the present invention is configured so that a light-emitting portion including the above-described vacuum ultraviolet-excitation blue phosphor of the present invention is irradiated with vacuum ultraviolet light from a light source, thereby obtaining visible light from the light-emitting portion. It is a thing. Specifically, a fluorescent lamp such as a rare gas discharge lamp including a light emitting portion containing the VUV-excited phosphor of the present invention and a light source for irradiating the light emitting portion with light such as vacuum ultraviolet light is exemplified.

The light emitting device of the present invention is also used as a light emitting unit of a plasma display device including a light emitting unit and a control unit for controlling light emission of the light emitting unit.

[0039]

Next, specific examples of the present invention and evaluation results thereof will be described.

Example 1 BaCO ₃ : 0.8 mol Mg (OH) ₂ : 1 mol Al ₂ O ₃ : 1 mol AlN: 1 mol, AlF ₃ : 0.01 mol Eu ₂ O ₃ : 0.2 mol The above-mentioned raw materials are sufficiently mixed. After that, the mixture was filled in an alumina crucible and fired in the atmosphere at 1400 ° C. for 4 hours (primary firing).
Next, the fired product was pulverized and sieved, filled again in an alumina crucible, graphite was placed thereon, and fired at 1560 ° C. for 3 hours in a reducing atmosphere (97% nitrogen + 3% hydrogen). (Secondary firing). The calcined product has exhibited a pale yellow, which was sieved treatment to obtain a _{Ba 0.8 Eu 0.2 MgAl 9 O 14} 2 divalent europium-activated barium magnesium aluminate oxynitride phosphor represented by N .

A PDP was produced using the obtained phosphor.

Example 2 BaCO ₃ : 0.8 mol Mg (OH) ₂ : 1 mol Al ₂ O ₃ : 4.5 mol AlN: 0.5 mol AlF ₃ : 0.01 mol Eu ₂ O ₃ : 0.2 mol In the same manner as in Example 1, Ba _0.8 Eu
_A divalent europium-activated barium magnesium aluminate nitride phosphor represented by _0.2 MgAl _9.5 O _15.5 N _0.5 was obtained, and was further used in the same manner as in Example 1 to obtain P
DP was prepared. Note that the phosphor obtained in this example also exhibited a pale yellow color as in Example 1.

Examples 3 and 4 Each of the secondary fired products obtained in Examples 1 and 2 was subjected to dispersion, washing with water, drying and sieving to obtain divalent europium-activated barium magnesium aluminate nitride. Phosphors were obtained, and a PDP was produced in the same manner as in Example 1 using each of the obtained phosphors. Each of the phosphors obtained in each of the examples was white.

Examples 5 to 9 A secondary baked product obtained in the same manner as in Example 1 except that the amounts of the starting materials AlN and Eu ₂ O ₃ were changed, was subjected to the same dispersion, washing and washing as in Example 3. After drying and sieving, 2 shown in Table 1
A europium-activated barium magnesium aluminate nitride phosphor was obtained. Further, a PDP was produced in the same manner as in Example 1 using each of the obtained phosphors. In addition,
Each of the phosphors obtained in each of these examples was white.

Comparative Example BaCO ₃ : 0.9 mol Mg (OH) ₂ : 1 mol Al ₂ O ₃ : 5 mol AlF ₃ : 0.01 mol Eu ₂ O ₃ : 0.1 mol The above raw materials were mixed and fired in the same manner as in Example 1. After that, dispersion, washing with water, drying and sieving are performed, and BaMgAl
A known blue phosphor represented by ₁₀ O ₁₇ : Eu was obtained. Further, using the obtained phosphor, in the same manner as in Example 1,
PDP was produced.

Each of the phosphors obtained in each of the above Examples and Comparative Examples was irradiated with vacuum ultraviolet rays having a wavelength of 147 nm, and the emission luminance and emission chromaticity were measured. The PDPs obtained in the above Examples and Comparative Examples were turned on, and their emission luminance and emission chromaticity were measured. Table 1 shows the measurement results together with the composition of the phosphor. The light emission luminance was shown as a relative value when the light emission luminance of the comparative example was set to 100.

[0047]

[Table 1]

As is clear from Table 1, the phosphor and the device according to the present invention have improved luminous brightness against vacuum ultraviolet rays as compared with those of the comparative example. Improvement was observed.

[0049]

As described above, according to the VUV-excited blue light-emitting phosphor or VUV-excited phosphor of the present invention, the luminous efficiency under VUV excitation can be greatly increased. Therefore, the VUV-excited blue-emitting phosphor or VUV-excited phosphor of the present invention is very useful as a phosphor used in a light-emitting device such as a PDP or a rare gas discharge fluorescent lamp using VUV as an excitation source. Light emission brightness can be increased.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4H001 CA04 CA07 XA07 XA08 XA12 XA13 XA56 YA63 5C040 GG08 KA03 KB03 KB28 MA03 MA05 5C043 AA02 BB04 BB09 DD28 EB04 EC16

Claims (9)

[Claims] 1. The general formula: Ba _{1 -a} Eu _a MgAl _b O _c N
_d (where a, b, c and d are 0.05 ≦ a ≦ 0.4, 7 ≦ b <
10, 10 ≦ c <17, and 0 <d ≦ 2). 2. The VUV-excited blue light-emitting phosphor according to claim 1, wherein d is a number satisfying 0 <d ≦ 1 in the general formula. . 3. A vacuum ultraviolet ray excited blue light emitting phosphor according to claim 1 or 2, wherein visible light is emitted by irradiation with vacuum ultraviolet light having a wavelength of 140 to 180 nm. 4. A vacuum ultraviolet ray excited phosphor containing a blue light emitting component, a green light emitting component, and a red light emitting component, wherein the blue light emitting component includes the vacuum ultraviolet ray excited blue light emitting phosphor according to claim 1 or 2. VUV-excited phosphor characterized. 5. The VUV-excited phosphor according to claim 4, wherein the VUV-excited phosphor emits visible light when irradiated with VUV light having a wavelength of 140 to 180 nm. 6. A light emitting device comprising the vacuum ultraviolet ray excited blue light emitting phosphor according to claim 1 or 2. 7. The light emitting device according to claim 6, further comprising: a light emitting unit including the vacuum ultraviolet ray excited blue light emitting phosphor according to claim 1 or 2; and a light source for irradiating the light emitting unit with vacuum ultraviolet light. Characteristic light emitting device. 8. A plasma display device comprising: the light emitting device according to claim 7; and control means for controlling light emission of the light emitting device. 9. The light emitting device according to claim 6, wherein the light emitting unit includes the vacuum ultraviolet ray excited phosphor according to claim 4.
A light emitting device, comprising: a fluorescent lamp including a light source for irradiating the light emitting unit with vacuum ultraviolet rays.