JPH0821321B2 - Fluorescent lamp manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a fluorescent lamp, and more particularly to a method for manufacturing a fluorescent lamp in which the adhesive strength between a glass tube and a fluorescent material layer is improved.

[Conventional technology]

When providing a phosphor layer on the inner surface of a glass tube for fluorescent lamps, suspend the phosphor in a solution of nitrocellulose in an organic solvent such as butyl acetate, apply the suspension to the inner surface of the glass tube, and dry. Was.

However, since the above-mentioned suspension uses an organic solvent, it has workability, economy, and risk of fire. Recently, an aqueous phosphor coating using a water-soluble binder has become mainstream. There is.

As a result of studying various water-soluble water-soluble binders, it was found that polyethylene oxide has the highest luminous efficiency, is not decomposed by bacteria, and is easily decomposed and removed by baking at a low temperature. However, in this case, there is a drawback that the adhesive strength between the phosphor layer and the glass tube is weak.

Therefore, many proposals have been made to improve the adhesive strength between the phosphor layer and the glass tube.

For example, in JP-B-60-41818, in order to improve adhesive strength and luminous efficiency, phosphor powder and fine particle aluminum oxide are suspended in a water-soluble lacquer, and boric acid and hydrogen peroxide are further added to obtain it. It has been proposed to apply the phosphor suspension to the inner surface of the glass tube and heat it to form the phosphor layer.

Further, in JP-A-58-126658, at least one selected from the group consisting of strontium nitrate and barium nitrate in an aqueous solution of a water-soluble binder and at least one selected from the group consisting of boric acid, boric anhydride and calcium pyrophosphate. Has been proposed.

[Problems to be solved by the invention]

In Japanese Patent Publication No. Sho 60-41818, boric acid and particulate aluminum oxide are added to a phosphor suspension, and hydrogen peroxide is further used. The reason why this hydrogen peroxide is used is that when boric acid is added to the phosphor suspension using a water-soluble binder, the organic matter is removed by heating in the baking step to remove the organic matter which is a component of the binder after forming the coating film. This is because carbon does not completely burn and carbon remains to lower the luminous efficiency of the fluorescent lamp. As a countermeasure against this, hydrogen peroxide is added to achieve complete burning of organic substances.

However, the above-mentioned phosphor suspension has a problem that the addition of hydrogen peroxide causes a large decrease in viscosity of the phosphor suspension, resulting in poor workability or poor coating appearance of the phosphor layer. It tends to occur.

Further, in recent years, as a measure for reducing the luminous flux after long-time lighting of a fluorescent lamp, a metal oxide coating, for example, an aluminum oxide coating is formed on the inner surface of the glass tube, and a fluorescent material layer is provided thereon.

In this case, for example, when the water-soluble binder is polyethylene oxide, even if fine particle aluminum oxide and boric acid are added to the phosphor suspension, the adhesive strength between the phosphor layer and the glass tube is still insufficient.

On the other hand, even in the specification of the phosphor suspension proposed in Japanese Patent Laid-Open No. 58-126658, there is a problem that the adhesive strength is remarkably weakened in the case of the fluorescent lamp provided with the metal oxide coating. .

Further, in the case of a rapid start fluorescent lamp having a transparent conductive coating such as tin oxide on the inner surface of the glass tube, there is a problem with the above-mentioned adhesive strength. In this case, the adhesion strength between the phosphor layer and the glass tube can be improved by increasing the addition amount of strontium nitrate or the like, but it has been confirmed that the discharge starting voltage of the fluorescent lamp increases.

In particular, a power-saving rapid-start type fluorescent lamp using a mixed gas containing a krypton as a sealed rare gas, for example, a mixed gas of krypton and neon, has a higher discharge starting voltage and is difficult to be put to practical use.

Therefore, an object of the present invention is to improve the adhesive strength between the phosphor layer and the glass tube while taking advantage of the above-mentioned advantages when the aqueous binder is particularly polyethylene oxide, and to improve the luminous efficiency of the fluorescent lamp and the discharge starting voltage. Another object of the present invention is to provide a method of manufacturing a fluorescent lamp that can reduce the temperature.

[Means for solving problems]

The gist of the present invention is to suspend a phosphor powder, an alkaline earth metal nitrate, aluminum oxide, boron oxide and an alkaline earth metal chloride in an aqueous solution of a binder,
A fluorescent lamp manufacturing method is characterized in that the suspension is applied to the inner wall surface of a glass tube and dried to form a phosphor layer.

[Action]

When fine particle aluminum oxide alone is added to the phosphor suspension, the adhesive strength between the phosphor layer and the glass tube is improved, but there is a disadvantage that the luminous flux of the lamp is greatly reduced. This is probably because the particulate aluminum oxide easily adsorbs the impure gas, and the impure gas remains in the fluorescent lamp.

The addition of the alkaline earth metal nitrate of the present invention, or the addition of the alkaline earth metal nitrate and boron oxide,
When the phosphor layer is applied and dried, nitric acid or a film of nitric acid and boric acid is formed on the surface of the fine particle aluminum oxide, which has the effect of reducing the impure gas absorbing ability of the fine particle aluminum oxide. It is estimated to be.

Further, the nitrate of alkaline earth metal partially decomposes in the firing step to release oxygen, which promotes combustion of the water-soluble binder.

Furthermore, for example, the decrease in the discharge start voltage of the power saving type rapid start fluorescent lamp described above due to the addition of the chloride of the alkaline earth metal has the effect of decreasing the resistance of the transparent conductive film. Presumed.

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

Example 1: 0. of polyethylene oxide as water soluble binder.
An 8 weight percent aqueous solution is used. Calcium halophosphate phosphor (white) 100 g was added to the aqueous solution 150cc chloride, Degussa Al _on -C as fine particles of aluminum oxide, barium nitrate as the nitrate of an alkaline earth metal, as chlorides boron oxide and an alkaline earth metal A predetermined amount of strontim is added to each and ball milling is performed for 30 minutes to prepare a phosphor suspension. This suspension is applied to the inner surface of a glass tube of FL40SS, which has a coating of aluminum oxide (Al _on -C manufactured by Degussa) _{on the} inner surface of the glass tube, and dried to form a phosphor layer. The amount of the fluorescent substance adhered is about 5.0 g / line. After that, FL40SSW goes through the normal lamp manufacturing process.
Was manufactured.

Table 1 shows the lamp characteristics of the present invention and the lamp characteristics for comparison with the lamp of the present invention.

Here, the adhesive strength in Table 1 is defined as follows. That is, as a measure of the strength of adhesion between the phosphor layer and the glass tube, the size of the peeling of the phosphor layer caused when a shock was applied to the outer surface of the fluorescent lamp with a piano wire having a load equivalent to 150 g. Is expressed by the average diameter (mmφ).

In addition, the added amount is shown as a weight percentage with respect to the phosphor.

As is clear from Table 1, in the comparative lamps No. 1 to 4, the adhesive strength was weak, and the phosphor layer was peeled off in a pinhole shape due to evaporation of mercury during long-term lighting of the lamp. It will not be put to practical use.

In the lamp Nos. 5 to 10 of the present invention, the adhesive strength is sufficient for practical use, and the lamp luminous flux (100h) and luminous flux maintenance rate are No. 9,10>No.7,8> No.5,6. However, it can be seen that the lamp characteristics are equal to or higher than those of the comparative lamps.

In particular, the specifications of the phosphor suspension shown in Nos. 9 and 10 were the most optimal.

Example 2: A transparent conductive coating made of tin oxide was provided on the inner surface of the glass tube, and aluminum oxide (Al _on
The fluorescent suspension shown in Example 1 (excluding Nos. 1 to 4) was applied to the glass tube for rapid start type fluorescent lamp (FLR40S) on which the coating of C) was formed, and dried to obtain fluorescence. Form body layers. After that, through the normal fluorescent lamp manufacturing process, the enclosed gas is krypton: neon = 65: 35% by volume.
Power saving type rapid start fluorescent lamp FLR4
0SW was manufactured.

 Table 2 shows the lamp characteristics.

As is clear from Table 2, the 100h luminous flux, the 1000h luminous flux maintenance factor and the adhesive strength have almost the same characteristics as the results in Table 1. However, the discharge inception voltage was lowest when strontium chloride was added, and the result was remarkable.

Although barium nitrate and strontium chloride were used in the above-mentioned examples, the same effect can be obtained by using other alkaline earth nitrates and chlorides.

[Effects of the Invention] As described above, the fluorescent lamp of the present invention improves the adhesive strength between the phosphor layer and the glass tube, improves the luminous efficiency of the lamp, and lowers the discharge starting voltage. Has the effect.

Claims (3)

[Claims] 1. A phosphor powder, an alkaline earth metal nitrate, aluminum oxide, boron oxide and an alkaline earth metal chloride are suspended in a water-soluble binder aqueous solution, and the suspension is applied to the inner wall surface of the glass tube. A method of manufacturing a fluorescent lamp, which comprises drying to form a phosphor layer. 2. The method of manufacturing a fluorescent lamp according to claim 1, wherein the water-soluble binder is polyethylene oxide. 3. A range first term of the claims, wherein said alkaline earth metal chlorides are SrCl ₂ or second
A method for manufacturing a fluorescent lamp according to the item.