JP3189853B2 - Phosphor for fluorescent 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 fluorescent material for a fluorescent lamp, and more particularly to a fluorescent material capable of improving the luminous flux maintenance factor of a fluorescent lamp and the blackening of a tube end.

[0002]

2. Description of the Related Art It is known that when a fluorescent lamp is turned on for a long time, the luminous flux of the lamp is reduced. Although the cause of the luminous flux decrease has not been clarified yet, the cause is the discoloration of the glass bulb due to the reaction between Na and mercury in the glass bulb. Reduction of luminous efficiency due to adsorption of mercury on phosphor. Generation of phosphor color centers by 185 nm mercury line. It is considered that most of the reaction is caused by the reaction between mercury and a phosphor or between mercury and a glass bulb.

[0003] As a method of preventing the adsorption of mercury and improving the luminous flux maintenance rate, for example, a method of providing a protective film such as alumina or magnesium oxide on the inner surface of a glass bulb, a method of containing a metal oxide in a glass bulb, and a method of fluorescing. A method of mixing a white substance such as alumina and magnesium oxide into the body has been performed, and JP-A-61-23678 discloses a method of providing a continuous alumina coating on the phosphor surface.

Incidentally, a rapid start type fluorescent lamp uses SnO ₂ , In ₂ O called a Nesa film as a starting aid.
_{3. A} transparent conductive film made of a conductive metal oxide such as ITO is provided. By providing this nesa film, the light emission starting voltage of the fluorescent lamp is reduced, and the lamp can be turned on without using a lighting tube. It is known that it can be done. Also in this rapid start fluorescent lamp, it is desired to lower the light emission starting voltage of the lamp as much as possible, that is, to improve the starting characteristics of the fluorescent lamp, in addition to the improvement of the luminous flux maintenance rate as in the ordinary fluorescent lamp.

[0005] The adsorption of mercury on the phosphor is prevented,
As a technique for improving the starting characteristics of a rapid start type fluorescent lamp, in Japanese Patent Application No. 3-204869, we applied a technique of performing a surface treatment with magnesium hydroxide on a phosphor for a lamp and charging the phosphor surface to +. Proposed.

[0006]

Although the lamp starting characteristics and the luminous flux maintenance rate have certainly been improved by the above-mentioned technology, however, as in the case of the conventional fluorescent lamp, depending on the type of the lamp and the method of forming the fluorescent film, only the area around the filament is improved. There is still an insufficient point about a problem called tube-end blackening in which mercury is adsorbed to the phosphor and blackens the fluorescent film in a ring shape.

Accordingly, the present invention has been made in view of such circumstances, and it is an object of the present invention to provide a fluorescent lamp having an excellent luminous flux maintenance factor and an excellent starting characteristic, and having a tube end black. It is an object of the present invention to provide a fluorescent material for a lamp for realizing a fluorescent lamp which does not cause the formation of a fluorescent lamp.

[0008]

Means for Solving the Problems The inventors of the present invention have developed a phosphor surface-treated with magnesium hydroxide which has been previously developed by the present inventors, and obtained a result of improving the phosphor surface by applying various treatments to the phosphor. The present inventors have newly found that the above problem can be solved by adding a specific substance to magnesium hydroxide and attaching the same to the present invention, and have accomplished the present invention. That is, the phosphor for a lamp of the present invention is characterized in that lanthanum hydroxide is attached to the surface of the phosphor in addition to magnesium hydroxide.

[0009] The amount of magnesium hydroxide attached is usually about 5% by weight or less, more preferably 0.01% to 2.0% by weight, based on the amount of Mg contained therein.
It is preferable to adjust the weight%. As magnesium hydroxide adheres, the phosphor is charged to + to prevent the adsorption of mercury, and the luminous flux maintenance rate of the fluorescent lamp is improved.
If it is more than 5% by weight, the phosphor tends to agglomerate in the coating slurry, making it difficult to obtain a uniform phosphor screen. In addition, there is a tendency that the improvement of the maintenance of the luminous flux of the fluorescent lamp and the rapid start type fluorescent lamp cannot be expected to increase the starting voltage.

The amount of lanthanum hydroxide attached can be adjusted to approximately 1% by weight or less, more preferably 0.05% to 0.5% by weight, in terms of the amount of La contained therein. preferable. As the lanthanum hydroxide is deposited,
It works effectively with magnesium hydroxide to maintain the luminous flux, but if it exceeds 1% by weight, the initial luminous flux of the lamp is reduced, so that it is not very preferable. On the other hand, magnesium hydroxide does not lower the initial luminous flux.

The phosphor of the present invention can be obtained, for example, by the method described below. First, the fired phosphor for a fluorescent lamp is placed in ion-exchanged water and sufficiently suspended. While stirring the suspension, an aqueous solution containing magnesium ions and an aqueous solution containing lanthanum ions were added.
Adjust to ~ 12. By adjusting the pH to the alkaline side, magnesium hydroxide and lanthanum hydroxide precipitated in the suspension adhere to the phosphor. After they have adhered to the phosphor, the stirring is stopped and allowed to stand. After the phosphor has settled, the supernatant is discharged, pure water is added again, and the mixture is stirred to wash the phosphor. This operation is repeated two or three times. Thereafter, the phosphor of the present invention can be obtained by separating and drying the phosphor according to a conventional method.

As the phosphor used in the present invention, any phosphor can be used as long as it is a phosphor for a lamp. For example, halophosphate phosphor represented by antimony-activated calcium halophosphate phosphor, phosphate phosphor represented by divalent europium-activated strontium pyrophosphate, and silicic acid represented by manganese-activated zinc silicate phosphor Salt phosphor, tungstate phosphor represented by calcium tungstate, aluminate phosphor represented by divalent europium activated barium magnesium aluminate phosphor, represented by trivalent europium activated yttrium oxide phosphor Rare earth phosphors to be used.

As the aqueous solution containing magnesium ions to be added, for example, an aqueous solution of a magnesium halide such as MgCl ₂ or MgF ₂ or an aqueous solution of a water-soluble magnesium salt such as Mg (NO ₃ ) ₂ or MgSO ₄ can be used. Further the aqueous solution containing lanthanum ions LaCl _3, LaI ₃ and halogenated lanthanum, an aqueous solution of _{La (NO) 3, La (} CH 3 COO) 3 aqueous lanthanum salts and the like can be used.

When manufacturing a fluorescent lamp using the phosphor of the present invention, a phosphor slurry in which an organic or inorganic binder and a phosphor are mixed is applied to a glass bulb, dried, and then the organic substance is removed. In order to form a phosphor screen, there is a step of baking the glass bulb at a temperature of 500 ° C. or more for several minutes. In this step, magnesium hydroxide and lanthanum hydroxide adhered to the phosphor of the present invention partially change to oxides, but do not particularly adversely affect the characteristics of the fluorescent lamp.

[0015]

The phosphor of the present invention has +
By attaching lanthanum hydroxide in addition to magnesium hydroxide, which is easily charged, the blackening of the tube end is less likely to occur and the luminous flux is less deteriorated. In addition, as will be described later, lanthanum hydroxide also acts as a binder for the fluorescent substance to the glass bulb, and has an effect of improving the binding force. Further, the rapid start type fluorescent lamp has an effect that the light emission starting voltage can be reduced by the positive charging property of magnesium hydroxide.

[0016]

The phosphor of the present invention will be described in detail in the following examples.

Example 1 CoolWhi was placed in a beaker containing 100 ml of ion-exchanged water (hereinafter, referred to as water).
Te antimony and 100 g of a manganese-activated calcium halophosphate phosphor were added, and the mixture was stirred well to suspend the phosphor. The suspension was added with Mg content of 1% Mg (NO ₃ ) ₂
20 ml of an aqueous solution and 20 ml of a 1% La (NO ₃ ) ₃ aqueous solution in terms of La were added. After the addition, 2% aqueous ammonia was added dropwise while stirring the suspension, and the pH was adjusted to 10.6 to precipitate magnesium hydroxide and lanthanum hydroxide. While maintaining the pH at 10.6, stirring was continued for 30 minutes, and the precipitated magnesium hydroxide and lanthanum hydroxide were uniformly attached to the phosphor. Thereafter, stirring was stopped, and after the phosphor had settled, the supernatant was discarded, water was added again, and the phosphor was washed with water. After washing the phosphor two or three times with water, the suspension was transferred to a Nutsche lined with filter paper, and suction-filtered to separate the phosphor. The separated phosphor is dried at 150 ° C. for 5 hours,
The phosphor for a lamp of the present invention was obtained by passing through a 250-mesh sieve.

30 g of the phosphor thus obtained is combined with 1%
30 g of a nitrocellulose-butyl acetate solution and 0.5 g of CBBP (a mixture of calcium barium borate and calcium phosphate) as a binder were mixed to form a phosphor coating slurry.

This coating slurry is applied to a FL40SS valve in which SnO ₂ is previously coated as a conductive oxide film on the inner surface of a glass bulb, and then dried in a conventional manner.
After baking at 00 ° C. for 5 minutes to form a fluorescent film, a base was attached, and a rapid start fluorescent lamp was manufactured.

Examples 2 to 6 The same procedures as in Example 1 were carried out except that the addition amounts of the aqueous magnesium solution and the aqueous lanthanum solution were changed as appropriate and the amounts of magnesium hydroxide and lanthanum hydroxide were changed as shown in Table 1. After obtaining the phosphor of the present invention, a rapid start type fluorescent lamp was produced in the same manner.

[Comparative Examples 1 to 3] As shown in Table 1, a phosphor to which only magnesium hydroxide was adhered, a phosphor to which only lanthanum hydroxide was adhered to the same phosphor as in Example 1, A fluorescent lamp was prepared in the same manner for the phosphor to which nothing was attached, and the fluorescent lamp was evaluated in the following manner together with the fluorescent lamp comprising the phosphor of the present invention. The results are shown in Table 1.

In this table, the amounts of Mg (OH) ₂ and La (OH) ₃ attached to the phosphor are all Mg, L
The luminous flux maintenance factor was measured as a luminous flux 30 minutes after the lamp was turned on and the lamp was stabilized, as an initial luminous flux.
The luminous flux after continuous lighting for 1000 hours is indicated by the luminous flux maintenance ratio with respect to the initial luminous flux. The starting voltage (Vs) indicates the voltage required for lighting the lamp at a constant current value, and the blackening at the tube end occurs when the blackening of the tube end occurs within 200 hours after the continuous lighting of the lamp. The results are shown as Δ, and those that did not occur even after 1000 hours or more are evaluated as ○, and the results of visual judgment are shown. Below margin

[0023]

[Table 1]

As shown in Table 1, the rapid start type fluorescent lamp using the phosphor of the present invention has an excellent luminous flux maintenance factor and can lower the light emission starting voltage. In addition, when magnesium hydroxide alone or lanthanum hydroxide alone was used, blackening of the tube ends occurred, whereas when both were present, blackening of the tube ends did not occur at all, and very good characteristics were exhibited.

Further, although not particularly described in the table, the fluorescent lamp obtained in Example 1 and the fluorescent lamp of Comparative Example 3 were played by playing the glass bulb with a piano wire from a certain distance with a certain force. When the peeling of the fluorescent film was tested, more than 10 cm ² of the fluorescent film of the lamp of Comparative Example 3 was peeled off, whereas only 5 cm ² or less of the fluorescent film of the lamp of the present invention was peeled off. From this, it was found that the lanthanum hydroxide attached to the phosphor of the present invention also has a function as a binder for increasing the binding force between the phosphor and the glass bulb.

[0026]

As described above, the phosphor of the present invention is:
By attaching magnesium hydroxide and lanthanum hydroxide to the particle surface, the luminous flux maintenance rate of the fluorescent lamp and the blackening of the tube end can be improved, and especially in the case of the rapid start type fluorescent lamp, the starting voltage is reduced. Can be lowered. In addition, the binding force of the fluorescent film can be increased.

────────────────────────────────────────────────── ─── Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) C09K 11/00-11/89 H01J 61/44-61/46 WPI / L (QUESTEL)

Claims (1)

(57) [Claims] Claims: 1. Magnesium hydroxide on the surface of phosphor particles,
And a phosphor for a fluorescent lamp to which lanthanum hydroxide is attached.