JP2765641B2 - Phosphor composition and low-pressure mercury lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor composition comprising a mixture of an infrared-emitting phosphor which emits near-infrared light near 740 nm excited by ultraviolet rays of 253.7 nm and a non-luminescent substance, and a phosphor composition comprising the same. The present invention relates to a low-pressure mercury lamp (hereinafter, referred to as a fluorescent lamp), and particularly relates to deterioration of the fluorescent material and the fluorescent lamp and improvement of a light flux.

[0002]

2. Description of the Related Art In general, infrared fluorescent lamps emitting near infrared rays have been used as fluorescent lamps for light sources for growing plants, in addition to ordinary fluorescent lamps emitting visible light. The phosphor used in the infrared fluorescent lamp has a general formula: RX
O ₂ : Fea (where R is at least one member of the group consisting of Li, Na, K and Rb, X is at least one member of Al and Ga, a is 0.001 to 0.1 gram atom trivalent Fe) Phosphors represented by ions (hereinafter, referred to as infrared light-emitting phosphors) are known. For example, LiAlO ₂ : F
The iron-activated lithium aluminate phosphor known as e is the most frequently used phosphor among them.

[0003] An infrared-emitting phosphor is a near-infrared-emitting phosphor which is excited by ultraviolet rays of 253.7 nm and has an emission peak near 740 nm. Since this phosphor contains an alkali metal such as Li or Na as can be seen from its general formula, a fluorescent lamp using the same is easy to form an amalgam by combining an alkali metal and Hg in a glass bulb, In addition, since the activator Fe is also unstable in the phosphor, there is a disadvantage that the luminous flux of the fluorescent lamp is extremely deteriorated. Further, since alkali metals easily react with the glass bulb, there is a disadvantage that the glass becomes brittle and easily broken.

[0004]

In order to solve these problems, various methods have been proposed. For example, there is a method of removing excess alkali metal by washing the phosphor with acid. In the case of an iron-activated lithium aluminate phosphor, Japanese Patent Publication No. 51-42436 discloses that the phosphor is fired twice in order to remove an excess amount of Li used as a flux, and in the second firing, A method is disclosed in which aluminum oxide (hereinafter, referred to as alumina) is added to convert the remaining excess Li as lithium aluminate. Further, Japanese Patent Application Laid-Open No. 1-215885 discloses a method in which alumina is added to the iron-activated lithium aluminate phosphor in a range of 0.5 to 10% by weight in the second firing and firing is performed at a high temperature. I have.

[0005] However, none of these methods is still sufficient to solve various problems of the infrared-emitting phosphor, and further improvement of the phosphor is strongly desired.

In view of such circumstances, the present invention reduces the adsorption of Hg to the alkali metal contained in the infrared-emitting phosphor to suppress the formation of amalgam and further prevents the reaction between the alkali metal and the glass bulb. By doing so, the phosphor and the fluorescent lamp using the phosphor are deteriorated and the luminous flux is improved.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted a number of experiments to improve the deterioration of infrared-emitting phosphors. It has been found that these problems can be solved by mixing or adhering to the light emitting phosphor, and the present invention has been accomplished.

The phosphor composition of the present invention has the following general formula: RX
O ₂ : Fea (where R is at least one member of the group consisting of Li, Na, K and Rb, X is at least one member of Al and Ga, a is 0.001 to 0.1 gram atom trivalent Fe) Ion), an average particle size of 1
It is characterized in that β-type or γ-type aluminum oxide of μm or less is mixed or adhered at a ratio of 0.5% by weight or more and 200% by weight or less.

Generally, an infrared-emitting phosphor is obtained as follows. First, sodium hydroxide, sodium carbonate,
An alkali metal compound such as lithium oxide, lithium carbonate, lithium hydroxide, and an Al compound or a Ga compound such as alumina, aluminum nitrate, aluminum hydroxide, and gallium oxide are mixed with an alkali metal and Al or Ga.
Are mixed in a dry or wet manner so that the amounts thereof are substantially equivalent to each other, and a trivalent iron salt such as ammonium ferric sulfate is added to F.
Mix so that e is approximately 0.001-0.1 gram atoms. Next, the mixture is placed in an alumina crucible or the like and fired in an air atmosphere at a temperature of 1000 ° C. or higher for 2 to 4 hours to obtain a mixture.

In the phosphor composition of the present invention, the particle size of the alumina to be mixed or adhered must be adjusted to 1 μm or less. If the particle size is larger than 1 μm, the phosphor is greatly deteriorated, and the life of the fluorescent lamp is shortened. The smaller the particle size, the better the deterioration is improved, and the less uneven the coating of the phosphor at the time of coating the glass bulb.

Alumina may be merely dry-mixed, but an organic aluminum compound such as aluminum alcoholate is used, and the average particle size is 1 μm or less according to a standard method.
The fine particles of aluminum oxide may be attached to the phosphor in a film form. That is, the organic aluminum compound is hydrolyzed.
The fine aluminum hydroxide obtained by dissolving
It is a method of attaching to. This aluminum hydroxide is
Easy due to short baking during light lamp manufacturing process
To aluminum oxide as fine particles.

The type of alumina must be β-type or γ-type. If it is an α-type, there is a tendency that favorable results cannot be obtained with respect to deterioration. It is more preferable to use gamma alumina having high reactivity.

The mixing or adhering amount is adjusted to a range of 0.5% by weight or more and 200% by weight or less, preferably 5% by weight or more and 150% by weight or less based on the phosphor. If the amount is less than 0.5% by weight, the effect of alumina cannot be obtained, and the phosphor deteriorates quickly. If the amount is more than 200% by weight, a practical lamp light beam cannot be obtained due to a decrease in initial light beam. .

[0014]

FIG. 1 shows that an iron-activated lithium aluminate phosphor is
A phosphor composition obtained by mixing α, β, and γ alumina fine powders having an average particle size of 0.1 μm at a ratio of 30% by weight was prepared as FL40.
FIG. 3 is a diagram illustrating a relationship between a lamp lighting time and a relative luminous flux of a lamp when the lamp is mounted on an SS fluorescent lamp and turned on. Note that the lamp light flux (initial light flux) 30 minutes after lighting is 100%.

Although the luminous flux of a fluorescent lamp gradually decreases as time passes, the fluorescent lamp having the phosphor composition of the present invention mixed with β-alumina or γ-alumina has a small reduction rate.

FIG. 2 shows that when a phosphor composition in which iron-activated lithium aluminate phosphor and α, β, and γ alumina having an average particle diameter of 0.1 μm are mixed in various ratios is used as a FL40SS fluorescent lamp, The figure showing the relationship between the mixing amount and the luminous flux maintenance ratio is shown. The luminous flux maintenance ratio is represented by a relative value of lamp luminous flux after 100 hours has elapsed / 0-hour lamp luminous flux.

As shown in this figure, when the mixing amount of the alumina fine powder is less than 0.5% by weight, the lamp luminous flux is reduced by about 40% or more compared to the initial luminous flux, while 5% by weight.
In the range of １５０150% by weight, the reduction is within about 20%. Moreover, γ-alumina and β-alumina are clearly superior.

FIG. 3 shows a case where a phosphor composition in which 20% by weight of γ-alumina having different particle sizes are mixed with an iron-activated lithium aluminate phosphor is used as a FL40SS fluorescent lamp.
The figure showing the relationship between the particle size of alumina and a luminous flux maintenance factor is shown. The luminous flux maintenance ratio is also expressed with a relative value with respect to the luminous flux after 100 hours.

If the average particle size of alumina is 1 μm or less, preferably 0.5 μm or less, the luminous flux maintenance factor of the lamp hardly changes, but the luminous flux maintenance factor tends to decrease as the particle size increases. If it is larger than 1 μm, the effect of alumina cannot be obtained.

FIG. 4 is a graph showing the relationship between the mixing amount and the initial luminous flux of the FL40SS fluorescent lamp when γ-alumina having an average particle size of 0.1 μm is mixed with the iron-activated lithium aluminate phosphor. . The initial luminous flux value when the mixing amount is 0 is 1
00%.

As shown in this figure, when γ-alumina is mixed, the lamp luminous flux decreases as the mixing amount of γ-alumina, which is a non-luminous substance, increases, but the mixing amount is about 20 On the contrary, up to the weight%, the initial luminous flux is improved.

As shown in FIG. 2, even when the mixing amount of alumina is 200% by weight or more, the luminous flux maintenance ratio does not decrease. However, as shown in FIG. 4, the initial luminous flux decreases and is not practical. The invention was limited to numerical values.

Further, FIG. 5 shows that the phosphor composition obtained by mixing gamma alumina having an average particle diameter of 0.1 μm with the iron-activated lithium aluminate phosphor as in FIG. FIG. 3 shows a diagram representing the relationship between the amount and the initial luminous flux of a compact fluorescent lamp. Generally, the compact lamp fluorescent lamp is discharged under a higher load than the FL40SS fluorescent lamp, so that the luminous flux is higher than that of the FL40SS fluorescent lamp, but the phosphor is usually greatly deteriorated.

As shown in this figure, gamma alumina was mixed,
When a compact fluorescent lamp is used, the initial deterioration (deterioration of the lamp luminous flux about 15 minutes after lighting) that occurs before the measurement of the initial luminous flux of the lamp is improved by mixing alumina, and the rate of deterioration is extremely reduced. The practical first luminous flux hardly drops. In the case of a high-load compact fluorescent lamp, the initial luminous flux is very little deteriorated, so that the initial luminous flux is greatly improved as compared with the FL40SS fluorescent lamp shown in FIG.

As shown in these figures, the phosphor composition of the present invention provides an infrared-emitting phosphor with a γ having an average particle size of 1 μm or less.
By mixing alumina or β-alumina, it is possible to prevent mercury from forming amalgam with the alkali metal in the phosphor, and it is possible to suppress deterioration of the phosphor and reduction in lamp luminous flux.

[0026]

The present invention will be described below in detail with reference to examples.

Example 1 121.9 g of lithium carbonate (Li ₂ CO ₃ ) and alumina (Al
₂ O ₃ ) 169 g, ferric nitrate nonahydrate {Fe (NO ₃ ) ₃
• Weigh out 8.1 g of 9H ₂ O and weigh them in a 300 ml magnetic pot containing alumina balls.
Rolled together with 0 ml for 5 hours and crushed and mixed. After drying, the pulverized mixture was filled in an alumina crucible, covered, and calcined in an air atmosphere at 1200 ° C. for 3 hours. After the firing, the obtained phosphor is pulverized and passed through a 300-mesh sieve to obtain LiAlO ₂ : F having an average particle size of 5 μm.
e phosphor was obtained.

1.6 g of γ-alumina fine powder having an average particle size of 0.05 μm (20% by weight based on the phosphor) was added to 8 g of the phosphor.
Was thoroughly mixed in a dry system to obtain a phosphor composition.

Further, butyl acetate 15 was added to the phosphor composition.
g, mixed well in a magnetic pot and slurried, poured into a glass tube, coated with a phosphor composition on the inner surface, dried, and baked at 450 ° C. for 15 minutes to obtain a fluorescent material of the present invention. A phosphor film of the body composition was formed. After that, gas filling, electrode attachment, etc. are performed according to a conventional method, and FL40
An SS fluorescent lamp was used.

When this fluorescent lamp was turned on and the luminous flux maintenance factor was measured after 100 hours, an improvement of 40% or more was observed as compared with the conventional fluorescent lamp which did not mix alumina.

Further, a glass tube destruction test was performed to measure the glass strength of the fluorescent lamp. The glass intensity was fixed on a desk after lighting for 100 hours, and 100%
g of iron ball was dropped, and the strength of the glass tube was simply measured at the height of the iron ball when the glass tube was broken.
The fluorescent lamp with the phosphor composition of the present invention broke at about 42 cm, whereas it broke at a height of 2 cm.

Example 2 As a phosphor material, 121.9 g of sodium carbonate (Na ₂ CO ₃ ) and alumina 153 were used.
g, 7.3 g of ferric nitrate nonahydrate were weighed, and these were crushed and mixed with about 50 ml of methanol for 5 hours in a 300 ml magnetic pot containing alumina balls. After drying, the pulverized mixture was filled in an alumina crucible, covered, and fired in an air atmosphere at 1300 ° C. for 2 hours. After the firing, the obtained phosphor is pulverized and
By passing through a mesh sieve, a NaAlO ₂ : Fe phosphor having an average particle size of 5.5 μm was obtained.

An average particle size of 0 . 5 μm γ
The phosphor composition of the present invention was obtained by mixing 1.6 g of alumina fine powder in a dry manner.

Further, using this luminescent composition, Example 1
A fluorescent lamp was prepared in the same manner as described above, and the luminous flux maintenance factor after the elapse of 100 hours was measured. As a result, an improvement of 40% or more was observed as compared with the fluorescent lamp in which γ-alumina was not mixed.

In the destruction test, the fluorescent lamp not mixed with γ-alumina was broken at 14 cm.
It of the invention broke at a height of 40 cm.

Example 3 As a phosphor material, 81.9 g of lithium carbonate (Li ₂ CO ₃ ) and 206 gallium oxide were used.
g of ferric nitrate nonahydrate was weighed and crushed and mixed with about 50 ml of methanol for 5 hours in a 300 ml magnetic pot containing alumina balls. After drying, the pulverized mixture was filled in an alumina crucible, covered, and fired in an air atmosphere at 1300 ° C. for 2 hours. After the firing, the obtained phosphor is pulverized and
By passing through a mesh sieve, a LiGaO ₂ : Fe phosphor having an average particle size of 4.2 μm was obtained.

Alumina fine powder was mixed with 8 g of this phosphor in the same manner as in Example 1 to obtain a phosphor composition of the present invention, and then a fluorescent lamp was produced in the same manner. When the percentage was measured, an improvement of 40% or more was also observed as compared with the case where γ-alumina was not mixed.

Similarly, in the destruction test, the fluorescent lamp not mixed with γ-alumina was broken at 18 cm, while that of the present invention was broken at a height of 42 cm.

[0039]

As described above, according to the present invention, the luminous flux and deterioration of the fluorescent lamp can be remarkably improved by mixing a small particle diameter γ or β alumina with the infrared light emitting phosphor. In particular, in a compact fluorescent lamp, the deterioration can be improved even though the phosphor is excited under more severe conditions than a general fluorescent lamp. Alumina mixed or adhered in the light emitting composition of the present invention is not only iron-activated lithium aluminate as in the prior art, but also other infrared-emitting phosphors containing an alkali metal activated by iron. Is also effective. Furthermore, by limiting the amount of alumina, a large amount of alumina can be used for the phosphor as compared with the conventional technique of mixing alumina with the infrared-emitting phosphor and firing the same, which is very economical. It is advantageous.

[Brief description of the drawings]

FIG. 1 is a diagram showing a comparison between a lighting time of a fluorescent lamp mounting a phosphor composition in which different aluminas are mixed and a luminous flux thereof.

FIG. 2 is a diagram showing a comparison between the alumina mixing amount of a phosphor composition in which different aluminas are mixed and the luminous flux maintenance factor of the fluorescent lamp.

FIG. 3 is a graph showing the relationship between the alumina particle size of the phosphor composition according to the present invention and the luminous flux maintenance factor of the fluorescent lamp.

FIG. 4 is a diagram showing the relationship between the amount of alumina mixed in the phosphor composition according to the present invention and the initial luminous flux of the fluorescent lamp.

FIG. 5 is a diagram showing the relationship between the amount of alumina mixed in the phosphor composition according to the present invention and the initial luminous flux of the compact fluorescent lamp.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-215885 (JP, A) JP-A-50-92876 (JP, A) JP-A-51-120986 (JP, A) JP-A-51-1982 120987 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09K 11/00-11/89 H01J 61/44

Claims (2)

(57) [Claims] (1) The general formula is RXO2: Fea (where R
Is at least one of the group consisting of Li, Na, K and Rb, X is at least one of Al and Ga, and a is 0.0
Β-type or γ-type aluminum oxide having an average particle size of 1 μm or less is added to the infrared-emitting phosphor represented by formula (01-0.1 gram atom of trivalent Fe ion).
A phosphor composition obtained by mixing or adhering at a ratio of not less than 200% by weight and not more than 200% by weight , and thereafter being obtained without heating at 500 ° C or more . 2. A low-pressure mercury lamp comprising the phosphor composition according to claim 1 as a phosphor film.