JPH09217059A - Blue color generating fluorescent material, production of the same and fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a blue color generating fluorescent material less in deterioration and without harming a light generating efficiency, and to provide a simple method for producing the same and also a fluorescent lamp less in variation of a chromaticity during lighting thereof. SOLUTION: This blue color generating fluorescent material is obtained by forming a covering layer consisting of at least one of tin oxide and indium oxide on the surface of an europium activated aluminate fluorescent material 2 expressed by the formula: (M1-x-y Eux Mny )O.aAl2 O3 (M is at least one kind selected from Mg, Ca, Sr and Ba, 0.01<=x<=0.1, 0<=y<=0.10, 1<=a<=5). Further, the weight ratio of the covering layer based on the aluminate fluorescent material 2 is preferably in the range of 0.001-0.5wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blue light emitting phosphor, a method of manufacturing the same, and a fluorescent lamp, and more particularly, a blue light emitting phosphor having excellent luminous efficiency and color rendering properties and less deterioration, a method of manufacturing the same and the phosphor thereof. The present invention relates to a fluorescent lamp which is formed in the same manner and has a small variation in emission chromaticity when the lamp is turned on.

[0002]

2. Description of the Related Art As a fluorescent lamp for general illumination, a three-wavelength type fluorescent lamp which has a high efficiency and a high color rendering property at the same time is widely used. This three-wavelength type fluorescent lamp is formed by forming a phosphor layer (phosphor film) in which three kinds of phosphors having blue, green and red emission having a relatively narrow band emission spectrum distribution are mixed at an arbitrary ratio. It is a fluorescent lamp that emits light of a target color temperature.

Conventionally, specific examples of the blue light emitting phosphor used in the above fluorescent lamp include, for example, Japanese Patent Publication No. 58-22.
Aluminate phosphor (M, Eu) O.a activated with divalent europium as disclosed in Japanese Patent No.
Al ₂ O ₃ or an aluminate (M, Eu, Mn) O.aAl activated with divalent europium and manganese as disclosed in Japanese Patent Publication No. 58-22496.
₂ O ₃ is known.

In order to improve the lamp characteristics of a three-wavelength fluorescent lamp using three types of phosphors having different emission colors,
It is necessary that each of the blue, red, and green light emitting phosphors has a high luminous efficiency and that all of them have little deterioration. The aluminate phosphor, which is widely used as the blue light emitting phosphor for the three-wavelength fluorescent lamp as described above, has a relatively high light emission output.

[0005]

However, the aluminate phosphor used as the blue light emitting component has a drawback that it has a high deterioration rate as compared with other red light emitting phosphors and green light emitting phosphors. There is a problem in that the commercial value of the fluorescent lamp is reduced as a result of the change in emission chromaticity over time due to the difference in the deterioration rate of the body.

The present invention has been made in order to solve the above problems, and provides a blue light emitting phosphor which is less deteriorated without impairing the light emitting efficiency, and a simple manufacturing method thereof, and at the time of lighting the lamp. It is an object of the present invention to provide a fluorescent lamp in which the variation of the emission chromaticity is small.

[0007]

In order to achieve the above object, the present inventor has studied various measures for preventing the deterioration of the blue light emitting phosphor, which is particularly deteriorated. That is, for the purpose of preventing the deterioration of the europium-activated aluminate phosphor and reducing the fluctuation of the emission chromaticity, a film made of various compounds is formed on the phosphor surface, and the kind and amount of the compounds forming the film are The effects on the lamp characteristics were compared and examined by experiments.

As a result, indium oxide (In ₂ O
₃ ) and tin oxide (SnO ₂ ) that are chemically stable and are integrally formed on the surface of the phosphor, so that the luminescence chromaticity changes (color shift) without significantly impairing the luminous efficiency.
It has been found that this can be effectively prevented. This is because by forming a chemically stable continuous film (coating layer) on the surface of the phosphor particles, the reaction between the phosphor and the inhibitor impurities that are enclosed and mixed in the lamp is suppressed, resulting in It is considered that deterioration with time can be effectively prevented. The present invention has been completed based on the above findings.

That is, the blue light emitting phosphor according to the present invention is
Formula _{(M 1-xy Eu x Mn} y) O · aAl 2 O 3 ( where M is at least one selected from Mg, Ca, Sr and Ba, 0.01 ≦ x ≦ 0.1,0 ≦ y ≦ 0.1
A coating layer made of at least one of tin oxide and indium oxide is formed on the surface of the europium-activated aluminate phosphor represented by 0,1 ≦ a ≦ 5). The weight ratio of the coating layer to the aluminate phosphor is 0.001 to 0.5% by weight, more preferably 0.01 to 0.1% by weight.

Here, at least one element M selected from Mg, Ca, Sr, and Ba is a metal component forming the base of the aluminate phosphor.

Divalent Eu (europium) acts as an activator (activator) for enhancing the luminous efficiency of the phosphor, and is added to the metal element M in an atomic ratio x of 0.01 to 0.1. To be done. If the addition ratio is less than 0.01, the effect of improving the luminous efficiency is small. On the other hand, if the addition ratio exceeds 0.1, coloring tends to occur, which rather impairs the luminous efficiency of the lamp.

Manganese (Mn) also acts as an activator, and the addition ratio y to the metal element M is 0 to 0.
In the range of 10, the luminous efficiency of the phosphor increases. Further, when the addition ratio a of the alumina (Al ₂ O ₃ ) component to 1 mol of the metal element M is in the range of 1 to 5 mol, high luminous efficiency can be obtained.

Tin oxide (SnO ₂ ) and indium oxide (In ₂ O ₃ ) form a coating layer formed on the surface of the phosphor, which blocks direct contact between the phosphor main body and the outside thereof, and encloses the lamp. It is used to prevent deterioration due to the reaction between a substance or an impurity component and a phosphor.

The weight ratio of the coating layer made of at least one of SnO ₂ and In ₂ O _{3 to} the aluminate phosphor is in the range of 0.001 to 0.5% by weight. If the weight ratio is less than 0.001% by weight, it is difficult to completely cover the surface of the phosphor particles, and it is not possible to sufficiently prevent the deterioration of the phosphor due to the reaction, and the chromaticity of the fluorescent lamp is reduced. It cannot be expected to reduce fluctuations. On the other hand, when the above-mentioned weight ratio exceeds 0.5% by weight, the luminous efficiency of the phosphor decreases. Therefore, the weight ratio of SnO ₂ or In ₂ O _{3 to} the phosphor is 0.001 to 0.5% by weight.
However, the range of 0.01 to 0.1% by weight is more preferable.

Further, in the method for producing a blue light emitting phosphor according to the present invention, at least one of a water-soluble indium compound and a tin compound is dissolved in water, and the general formula (M
_{1-xy Eu x Mn y)} O · aAl 2 O 3 ( where, M is M
at least 1 selected from g, Ca, Sr and Ba
Seed, 0.01 ≦ x ≦ 0.1, 0 ≦ y ≦ 0.10, 1 ≦ a
The europium-activated aluminate phosphor represented by ≦ 5) is dispersed in water, and the hydroxide produced by adjusting the pH of the resulting mixed solution is adhered to the surface of the aluminate phosphor and dried. Further, a heating dehydration treatment is performed to form a coating layer made of at least one of tin oxide and indium oxide on the surface of the aluminate phosphor.

The water-soluble indium compound and tin compound are not limited to oxides of In and Sn, but may be In or S by a hydrolysis reaction or a neutralization reaction.
In or Sn hydroxides, nitrates, etc. that generate n hydroxides can be used.

The blue light emitting phosphor of the present invention can be manufactured by the following specific processing operations. That is,
After adding the above indium compound or tin compound to pure water,
Sufficiently agitate to dissolve the compound to obtain a solution, and aluminate phosphor powder is added to the solution to be sufficiently agitated and dispersed to obtain a mixed solution. Next, by adding an alkali source such as ammonia to the obtained mixed liquid, the pH of the mixed liquid is adjusted to the range of 5.0 ± 0.5, and the produced colloidal indium hydroxide or tin hydroxide is added. Are adhered to the surface of aluminate phosphor particles.

Note that if an excessive amount of alkali is added at the time of adjusting the pH, the indium hydroxide once formed becomes an indium salt, while tin hydroxide becomes a stannate salt and is dissolved again. .

Next, the suspension of the phosphor to which the hydroxide is attached is filtered, and the filter residue is dried at 100 ± 20 ° C., after which the phosphor to which indium hydroxide is attached is 500 ± 10.
0 ° C, phosphor with tin hydroxide attached is 300 ± 100
By performing the heat dehydration treatment at a temperature of ° C, a blue light emitting phosphor having a surface integrally formed with a coating layer made of indium oxide or tin oxide can be obtained.

Further, in the fluorescent lamp according to the present invention, the blue light emitting phosphor prepared as described above, another red light emitting phosphor and a green light emitting phosphor are mixed in a mixing ratio such that a predetermined color temperature is obtained, Further, the obtained mixture is uniformly dispersed in a binder in which nitrocellulose, polyethylene oxide or the like is dissolved to form a phosphor slurry, and this phosphor slurry is applied to the inner wall surface of the glass tube (bulb) 1 as shown in FIG. Light emitting layer (phosphor layer) 2 by coating, drying and baking
The lamp is manufactured in accordance with a normal lamp manufacturing process in which the lamp is integrally formed.

According to the blue light emitting phosphor having the above structure, the method for manufacturing the same, and the fluorescent lamp, since the chemically stable coating layer made of indium oxide or tin oxide is formed on the surface of the phosphor, it is present in the lamp. The reaction between the blocking impurities and the phosphor is effectively suppressed, and deterioration of the phosphor over time can be prevented. Therefore, without significantly impairing the luminous efficiency,
It is possible to obtain a fluorescent lamp with a small variation in emission chromaticity.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described.
A more specific description will be given with reference to the following examples and comparative examples.

Example 1 and Comparative Example 1 In 800 cc of pure water, 0.5 g of tin nitrate (Sn (NO
₃ ) ₄ ) was charged and stirred to completely dissolve Sn (NO ₃ ) ₄ . Next, the composition formula is (Ba _0.45 Mg _0.5 E
u _0.05 ) O · 2.7Al ₂ O ₃ and 100 g of aluminate blue phosphor powder activated by divalent europium
Was added to the above solution and stirred sufficiently to give a mixed solution. After that, ammonia is added to the mixed solution to add p of the mixed solution.
The H was adjusted to 5, and the generated tin hydroxide and the phosphor powder were sufficiently stirred to deposit tin hydroxide on the phosphor powder surface. Then, the mixture is suction filtered to remove the residue on the filter paper at a temperature of 1
A coating layer made of tin oxide (SnO ₂ ) was formed on the surface of each phosphor powder by drying at 00 ° C. for 24 hours and further performing heat dehydration treatment at a temperature of 300 ° C. for 3 hours. Further, the blue light emitting phosphor according to Example 1 was prepared by sieving this phosphor.

When the surface of the prepared blue light emitting phosphor was analyzed, a coating layer made of tin oxide (SnO ₂ ) was uniformly formed on the phosphor surface at a weight ratio of 0.1% by weight with respect to the phosphor. .

A blue-emitting phosphor powder made of europium-activated aluminate prepared as described above, a (Y, Eu) ₂ O ₃ phosphor powder as a red-emitting component, and (La, Ce, Tb) PO ₄ phosphor powder was uniformly mixed at a mixing ratio such that the relative color temperature was 5000 K, to prepare a three-wavelength mixed phosphor for Example 1.

Next, 100 g of the above three-wavelength type mixed phosphor was added and mixed into 100 cc of a nitrocellulose solution consisting of 2% by weight of nitrocellulose (NC) and 98% by weight of butyl acetate to prepare a phosphor slurry. Then, the phosphor slurry is applied to the inner surface of a glass bulb (glass tube) 1 as shown in FIG. 1, and dried and baked to form a phosphor layer 2, and then discharge is performed in accordance with a normal lamp manufacturing process. The FCL30EX-N / 28 type fluorescent lamp according to Example 1 was manufactured through steps such as mounting a base provided with an electrode 3 and a socket for use on the end of the glass bulb 1.

On the other hand, a fluorescent lamp according to Comparative Example 1 was manufactured by treating under the same conditions as in Example 1 except that the coating layer made of tin oxide (SnO ₂ ) was not formed on the surface of the phosphor powder.

Example 1 and Comparative Example 1 thus manufactured
For each fluorescent lamp according to the above, the initial light emission output and light emission chromaticity immediately after production were measured, and the light emission output and light emission chromaticity after 1000 hours of lighting were measured.
Were obtained.

The luminous chromaticity (x, y) of the lamp is measured at 0 hours and 1000 hours, and the change value Δx of the luminous chromaticity is the chromaticity x ₀ to 100 at the time of initial light emission.
It is a value obtained by subtracting chromaticity x ₁₀₀₀ after lighting for 0 hour. Δy is also obtained for the chromaticity y.

The magnitude M of the chromaticity fluctuation is calculated by the following equation (1), and the reduction rate of the luminescence chromaticity change is calculated by the magnitude M ₁ of the chromaticity fluctuation in the fluorescent lamp of the comparative example in which the covering layer is not formed. 4 shows the reduction ratio from the above to the magnitude M ₂ of the chromaticity fluctuation in the fluorescent lamp of the example.

[0031]

[Equation 1]

As is clear from the results shown in Tables 1 and 2,
When the initial emission output of the conventional fluorescent lamp without the coating layer (Comparative Example 1) was set to a reference value (100%), the initial emission output of the fluorescent lamp according to Example 1 was 99.8%, which was slightly lowered. There is. However, comparing the light emission outputs after 1000 hours of lighting, 86.2 in Comparative Example 1.
%, Whereas the fluorescent lamp according to Example 1 showed a small decrease of 88.5% and was found to have excellent lamp characteristics.

Regarding the variability of emission chromaticity, in Comparative Example 1, Δx = + 0.020 and Δy = + 0.017.
While in the first embodiment, Δx = +
0.010, Δy = + 0.009, which is a small value, and the variation of emission chromaticity due to the formation of the coating layer is 48.8%.
Has been reduced. Therefore, according to this example, it was found that a high-quality fluorescent lamp in which the variation of the emission chromaticity is suppressed can be obtained.

Example 2 and Comparative Example 2 2.5 g of tin nitrate (Sn (NO
₃ ) ₄ ) was charged and stirred to completely dissolve Sn (NO ₃ ) ₄ . Next, the composition formula is (Ba _0.45 Mg _0.5 E
u _0.05 ) O · 2.7Al ₂ O ₃ and 100 g of aluminate blue phosphor powder activated by divalent europium
Was added to the above solution and stirred sufficiently to give a mixed solution. After that, ammonia is added to the mixed solution to add p of the mixed solution.
The H was adjusted to 5, and the generated tin hydroxide and the phosphor powder were sufficiently stirred to deposit tin hydroxide on the phosphor powder surface. Then, the mixture is suction filtered to remove the residue on the filter paper at a temperature of 1
A coating layer made of tin oxide (SnO ₂ ) was formed on the surface of each phosphor powder by drying at 00 ° C. for 24 hours and further performing heat dehydration treatment at a temperature of 300 ° C. for 3 hours. Further, the blue light emitting phosphor according to Example 2 was prepared by sieving this phosphor.

When the surface of the prepared blue-emitting phosphor was analyzed, a coating layer made of tin oxide (SnO ₂ ) was uniformly formed on the surface of the phosphor at a weight ratio of 0.5% by weight with respect to the phosphor. .

A blue light emitting phosphor powder made of europium activated aluminate prepared as described above, a (Y, Eu) ₂ O ₃ phosphor powder as a red light emitting component, and a (La, Ce, Tb) PO ₄ phosphor powder was uniformly mixed at a mixing ratio such that the relative color temperature was 5000 K, to prepare a three-wavelength mixed phosphor for Example 2.

Next, using the above-mentioned three-wavelength type mixed phosphor, the FCL30EX- according to the second embodiment was subjected to the same phosphor layer forming process as in the first embodiment and the usual lamp manufacturing process.
An N / 28 type fluorescent lamp was manufactured.

On the other hand, a fluorescent lamp according to Comparative Example 2 was manufactured by treating under the same conditions as in Example 2 except that the coating layer made of tin oxide (SnO ₂ ) was not formed on the surface of the phosphor powder.

Example 2 and Comparative Example 2 thus manufactured
For each fluorescent lamp according to the above, the initial light emission output and light emission chromaticity immediately after production were measured, and the light emission output and light emission chromaticity after 1000 hours of lighting were measured.
Were obtained. Then, the lamp characteristics were evaluated in the same manner as in Example 1.

As is clear from the results shown in Tables 1 and 2,
When the initial emission output of the conventional fluorescent lamp without the coating layer (Comparative Example 2) was set to a reference value (100%), the initial emission output of the fluorescent lamp according to Example 2 was 99.5%, which was slightly lowered. There is. However, comparing the light emission outputs after 1000 hours of lighting, in Comparative Example 2, it was 86.2.
%, The fluorescent lamp according to Example 1 showed a small decrease of 88.3%, and it was proved that the lamp characteristics were excellent.

Regarding the variability of emission chromaticity, in Comparative Example 2, Δx = + 0.020 and Δy = + 0.017.
While in the second embodiment, Δx = +.
0.012, Δy = + 0.009, which is a small value, and the formation of the coating layer causes a variation of 4 chromaticity of 42.9%.
Has been reduced. Therefore, according to this example, it was found that a high-quality fluorescent lamp in which the variation of the emission chromaticity is suppressed can be obtained.

Examples 3 to 8 and Comparative Examples 3 to 8 As shown in Table 1, the composition of the blue light emitting phosphor and the weight ratio of the coating layer made of SnO ₂ were set in the range of 0.001 to 0.3% by weight. A blue light emitting phosphor was prepared under the same conditions as in Example 1 except that the FCL30E according to Examples 3 to 8 having the same dimensions as in Example 1 was prepared using the phosphor.
An X-N / 28 type fluorescent lamp was manufactured.

On the other hand, the same treatments as in Examples 3 to 8 were carried out except that the coating layer was not formed, and the corresponding Comparative Examples 3 to 3 respectively.
The fluorescent lamp according to No. 8 was manufactured.

Then, the emission output characteristics and the variation characteristics of the emission chromaticity of the fluorescent lamps according to the respective examples and comparative examples were measured and the results shown in Table 2 were obtained.

As is clear from the results shown in Table 2, the fluorescent lamps according to Examples 3 to 8 were observed to have a tendency that the initial emission output slightly decreased as compared with the corresponding lamps of Comparative Examples 3 to 8. However, it has been found that since the coating layer is formed on the phosphor, the deterioration with time is small, and the variation in emission chromaticity can be significantly reduced to 27 to 49%.

Example 9 and Comparative Example 9 0.4 g of indium nitrate (In) was added to 800 cc of pure water.
(NO ₃ ) ₃ ) was charged and stirred to completely dissolve In (NO ₃ ) ₃ . Next, the composition formula is (Ba _0.45 Mg _0.5 E
u _0.05 ) O · 2.7Al ₂ O ₃ and 100 g of aluminate blue phosphor powder activated by divalent europium
Was added to the above solution and stirred sufficiently to give a mixed solution. After that, ammonia is added to the mixed solution to add p of the mixed solution.
The H was adjusted to 5, and the generated indium hydroxide and the phosphor powder were sufficiently stirred to adhere indium hydroxide to the phosphor powder surface. Next, the mixed solution is suction-filtered, the residue on the filter paper is dried at a temperature of 100 ° C. for 24 hours, and then the temperature is adjusted to 60 ° C.
A coating layer made of indium oxide (In ₂ O ₃ ) was formed on the surface of each phosphor powder by performing a heat dehydration treatment at 0 ° C. for 3 hours. Furthermore, the blue light-emitting phosphor according to Example 9 was prepared by sieving this phosphor.

The surface of the prepared blue-emitting phosphor was analyzed, and it was found that a coating layer made of indium oxide (In ₂ O ₃ ) was uniformly formed on the surface of the phosphor at a weight ratio of 0.1% by weight with respect to the phosphor. Was there.

A blue light emitting phosphor powder composed of europium activated aluminate prepared as described above, a (Y, Eu) ₂ O ₃ phosphor powder as a red light emitting component, and (La, as a green light emitting component). Ce, Tb) PO ₄ phosphor powder was uniformly mixed at a mixing ratio such that the relative color temperature was 5000 K, to prepare a three-wavelength mixed phosphor for Example 9.

Next, 100 g of the above three-wavelength mixed phosphor was added and mixed into 100 cc of a nitrocellulose solution consisting of 2% by weight of nitrocellulose (NC) and 98% by weight of butyl acetate to prepare a phosphor slurry. Then, the phosphor slurry is applied to the inner surface of a glass bulb (glass tube) 1 as shown in FIG. 1, and dried and baked to form a phosphor layer 2, and then discharge is performed in accordance with a normal lamp manufacturing process. The FCL30EX-N / 28 type fluorescent lamp according to Example 9 was manufactured through steps such as mounting the electrode 3 for use with and a base provided with a socket on the end of the glass bulb 1.

On the other hand, a fluorescent lamp according to Comparative Example 9 was manufactured by treating under the same conditions as in Example 9 except that a coating layer made of indium oxide (In ₂ O ₃ ) was not formed on the surface of the phosphor powder. .

Example 9 and Comparative Example 9 thus produced
For each fluorescent lamp according to the above, the initial light emission output and light emission chromaticity immediately after production were measured, and the light emission output and light emission chromaticity after 1000 hours of lighting were measured.
Were obtained. Then, in the same manner as in Example 1, the lamp characteristics were comparatively evaluated.

As is clear from the results shown in Tables 1 and 2,
When the initial light emission output of the conventional fluorescent lamp (Comparative Example 9) in which the coating layer is not formed is set to the reference value (100%), the initial light emission output of the fluorescent lamp according to Example 9 becomes 98.6%, which is slightly decreased. There is. However, comparing the light emission outputs after 1000 hours of lighting, in Comparative Example 9, it is 86.2.
%, Whereas the fluorescent lamp according to Example 9 showed a small decrease of 86.5%, and it was found that the lamp characteristics were excellent, although slight.

Regarding the variability of emission chromaticity, in Comparative Example 9, Δx = + 0.020 and Δy = + 0.017.
While in the ninth embodiment, Δx = +
0.014, Δy = + 0.010, which is a small value, and the change in emission chromaticity is 34.5% due to the formation of the coating layer.
Has been reduced. Therefore, according to this example, it was found that a high-quality fluorescent lamp in which the variation in the emission chromaticity was suppressed to a low level could be obtained.

Example 10 and Comparative Example 10 2.0 g of indium nitrate (In
(NO ₃ ) ₃ ) was charged and stirred to completely dissolve In (NO ₃ ) ₃ . Next, the composition formula is (Ba _0.45 Mg _0.5 E
u _0.05 ) O · 2.7Al ₂ O ₃ and 100 g of aluminate blue phosphor powder activated by divalent europium
Was added to the above solution and stirred sufficiently to give a mixed solution. After that, ammonia is added to the mixed solution to add p of the mixed solution.
The H was adjusted to 5, and the generated colloidal indium hydroxide and the phosphor powder were sufficiently stirred to deposit indium hydroxide on the phosphor powder surface. Next, the mixed solution is subjected to suction filtration, the residue on the filter paper is dried at a temperature of 100 ° C. for 24 hours, and further subjected to a heat dehydration treatment at a temperature of 600 ° C. for 3 hours, so that each phosphor powder surface has indium oxide (In
_A coating layer of ₂ O ₃ ) was formed. Further, this phosphor was sieved to prepare a blue light emitting phosphor according to Example 10.

When the surface of the prepared blue light emitting phosphor was analyzed, a coating layer made of indium oxide (In ₂ O ₃ ) was uniformly formed on the phosphor surface at a weight ratio of 0.5% by weight with respect to the phosphor. Was there.

A blue-emitting phosphor powder made of europium-activated aluminate prepared as described above, a (Y, Eu) ₂ O ₃ phosphor powder as a red-emitting component, and a (La, Ce, Tb) PO ₄ phosphor powder was uniformly mixed at a mixing ratio such that the relative color temperature was 5000 K, to prepare a three-wavelength mixed phosphor for Example 10.

Next, 100 g of the above three-wavelength mixed phosphor was added and mixed into 100 cc of a nitrocellulose solution consisting of 2% by weight of nitrocellulose (NC) and 98% by weight of butyl acetate to prepare a phosphor slurry. Then, the phosphor slurry is applied to the inner surface of a glass bulb (glass tube) 1 as shown in FIG. 1, and dried and baked to form a phosphor layer 2, and then discharge is performed in accordance with a normal lamp manufacturing process. The FCL30EX-N / 28 type fluorescent lamp according to Example 10 was manufactured through steps such as mounting the electrode 3 for use with and a base provided with a socket on the end of the glass bulb 1.

On the other hand, a fluorescent lamp according to Comparative Example 10 was manufactured by treating under the same conditions as in Example 10, except that the coating layer made of indium oxide (In ₂ O ₃ ) was not formed on the surface of the phosphor powder. .

With respect to each of the fluorescent lamps of Example 10 and Comparative Example 10 thus manufactured, the initial light emission output and light emission chromaticity immediately after the manufacture were measured, and the light emission output and light emission chromaticity after 1000 hours of lighting were measured, The results shown in Tables 1 and 2 were obtained. Then, in the same manner as in Example 1, the lamp characteristics were comparatively evaluated.

As is clear from the results shown in Tables 1 and 2,
When the initial light emission output of the conventional fluorescent lamp (Comparative Example 10) that does not form a coating phase is set to a reference value (100%), Example 10 is used.
The initial emission output of the fluorescent lamp according to
It is slightly lower. Further, comparing the light emission outputs after 1000 hours of lighting, in Comparative Example 10, 86.2%
On the other hand, in the fluorescent lamp according to the tenth embodiment, it is reduced to 85.4%.

However, regarding the variability of the emission chromaticity, in Comparative Example 10, Δx = + 0.020, Δy =
On the other hand, the values are as large as +0.017, and in Example 10, the values are as small as Δx = + 0.008 and Δy = + 0.009, and the formation of the coating layer reduces the variation in emission chromaticity by 54.1%. ing. Therefore, according to this example, it was found that a high-quality fluorescent lamp with little variation in emission chromaticity can be obtained.

Examples 11 to 16 and Comparative Examples 11 to 16 As shown in Table 1, the composition of the blue light emitting phosphor and the weight ratio of the coating layer made of In ₂ O ₃ were 0.001 to 0.3% by weight. A blue light emitting phosphor was prepared under the same conditions as in Example 9 except that the range was changed, and the FCL according to Examples 11 to 16 having the same dimensions as in Example 9 were prepared using the phosphor.
A 30EX-N / 28 type fluorescent lamp was manufactured.

On the other hand, the fluorescent lamps according to Comparative Examples 11 to 16 were manufactured in the same manner as in Examples 11 to 16 except that the coating layer was not formed.

The emission output characteristics and the emission chromaticity variation characteristics of the fluorescent lamps according to each of the examples and comparative examples were measured, and the results shown in Tables 1 and 2 below were obtained.

[0065]

[Table 1]

[0066]

[Table 2]

As is clear from the results shown in Table 2, the fluorescent lamps according to Examples 11 to 16 have the corresponding Comparative Example 11
It can be observed that the initial light emission output is slightly decreased as compared with the lamps Nos. 16 to 16, but since the coating layer is formed on the phosphor, the deterioration over time is small, and the variation of the emission chromaticity is 34%.
It was found that the amount could be significantly reduced to ~ 53%.

[0068]

As described above, according to the blue light emitting phosphor, the method for manufacturing the same and the fluorescent lamp according to the present invention, a chemically stable coating layer made of indium oxide or tin oxide is formed on the surface of the phosphor. Therefore, the reaction between the blocking impurities existing in the lamp and the phosphor is effectively suppressed, and the deterioration of the phosphor over time can be prevented. Therefore, it is possible to obtain the fluorescent lamp in which the variation of the emission chromaticity is small without significantly impairing the luminous efficiency.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a fluorescent lamp according to the present invention with a part broken away.

[Explanation of symbols]

 1 glass tube (glass bulb) 2 light emitting layer (phosphor layer) 3 electrode

Claims (6)

[Claims] 1. A general formula _{(M 1-xy Eu x Mn} y) O · a
Al ₂ O ₃ (where M is at least one selected from Mg, Ca, Sr and Ba, 0.01 ≦ x ≦ 0.1,
0 ≦ y ≦ 0.10, 1 ≦ a ≦ 5), and a coating layer made of at least one of tin oxide and indium oxide is formed on the surface of the europium-activated aluminate phosphor, which emits blue light. body. 2. The blue light-emitting phosphor according to claim 1, wherein the weight ratio of the coating layer to the aluminate phosphor is 0.001 to 0.5% by weight. 3. The blue light emitting phosphor according to claim 1, wherein the weight ratio of the coating layer to the aluminate phosphor is 0.01 to 0.1% by weight. Thereby dissolving at least one of water wherein the water-soluble indium compound and tin compound, the general formula _{(M 1-xy Eu x Mn} y) O · aAl 2 O 3 ( where,
M is at least one selected from Mg, Ca, Sr and Ba, 0.01 ≦ x ≦ 0.1, 0 ≦ y ≦ 0.10,
The europium-activated aluminate phosphor represented by 1 ≦ a ≦ 5) was dispersed in water, and the hydroxide produced by adjusting the pH of the obtained mixed liquid was adhered to the surface of the aluminate phosphor. A method for producing a blue light-emitting phosphor, comprising forming a coating layer made of at least one of tin oxide and indium oxide on the surface of the aluminate phosphor by further drying and then performing a heat dehydration treatment. 5. The general formula _{(M 1-xy Eu x Mn} y) O · a
Al ₂ O ₃ (where M is at least one selected from Mg, Ca, Sr and Ba, 0.01 ≦ x ≦ 0.1,
0 ≦ y ≦ 0.10, 1 ≦ a ≦ 5) Fluorescence containing a blue-emitting phosphor in which a coating layer made of at least one of tin oxide and indium oxide is formed on the surface of the europium-activated aluminate phosphor A fluorescent lamp having a body layer formed on the inner wall surface of a glass tube. 6. The fluorescent lamp according to claim 5, wherein the weight ratio of the coating layer to the aluminate phosphor is 0.001 to 0.5% by weight.