JPS61176049A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To reinforce the adhesive strength of a phosphor film and improve the optical flux maintainability rate of a fluorescent lamp after it is lit for a long period of time by forming a first layered thin film consisting of aluminum oxide and antimony oxide on the inner surface of a nonlinear type glass tube and then forming a second layered phosphor film on said thin film. CONSTITUTION:Airtight space is formed with the stem 1 and outer tube 4 of a fluorescent lamp and the electrode 2 of each inner tube 3 is airtightly sealed in this stem 1. A thin film 5 made of a compound of aluminum oxide and antimony oxide is formed on the inner surface of each of these inner tubes 3 as the first layer. In addition, the surface of the thin film 5 is coated with phosphor film 6 as the second layer. Besides, the coating strength of the phosphor film 6 is reinforced and the coloring of the inner tubes 3 generated when mercury ions reach the inner surface of the inner tubes 3 is prevented, then the optical flux maintainability rate of the fluorescent lamp after it is lit for a long period of time is improved.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a fluorescent lamp, and in particular to a lamp in which the luminous flux maintenance rate of the fluorescent lamp is improved and the adhesion strength of the phosphor film is improved. Regarding.

[Background of the invention]

In recent years, efforts have been made to miniaturize fluorescent lamps and develop fluorescent lamps that can replace incandescent light bulbs.

For example, two electrodes are provided on a stem, one end is hermetically sealed to the stem surrounding one of the electrodes, the other curved end is opened near the sealed part, and a phosphor is provided on the inner surface. It is equipped with a pair of glass inner tubes covered with a membrane, and a glass outer tube that covers the pair of inner tubes and is hermetically sealed to the stem, and a rare gas and mercury are sealed in the outer tube. A light lamp (hereinafter referred to as a bulb-shaped fluorescent lamp) has been proposed.

FIG. 1 shows a typical example of this type of lamp.

In the case of this light bulb-shaped fluorescent lamp, one drawback is that the luminous flux maintenance rate after long-term operation is lower than that of general fluorescent lamps due to the normally high tube wall load.

As a result of examining a light bulb-shaped fluorescent lamp whose luminous flux maintenance rate decreased after being lit for several thousand hours, it was found that the luminous flux maintenance rate decreased significantly because the inner surface of the inner tube glass was colored black.

As a result of investigating the cause of the blackening of the inner surface of the inner tube glass using IMA, mercury was detected in the glass corresponding to the blackening state of the glass. This is thought to be due to the fact that mercury ions that have passed through the 1-year-old photoreceptor film first enter the surface of the glass, diffuse into the interior of the glass, and become colored.

In the light bulb-shaped fluorescent lamp mentioned above, significantly more mercury ions penetrate into the glass than in a general fluorescent lamp.
This is thought to be due to the following reasons.

In other words, in a light bulb-shaped fluorescent lamp, 1
The openings of the pair of inner tubes are connected by discharge plasma, and a portion of this plasma is diffused throughout the outer tube. Since the diffusion speed of electrons is significantly higher than that of plasma ions, more electrons than plasma ions fly to the outside of the inner tube, and the outside of the inner tube has a negative potential with respect to the plasma inside the inner tube.

Therefore, mercury ions, which are plasma ions in the plasma inside the inner tube, receive a force toward the outer circumference of the inner tube, and the number of mercury ions that pass through the phosphor film and reach the inner surface of the inner tube increases. This is significantly higher than in the case of ordinary fluorescent lamps that do not have this.

Furthermore, in a light bulb-shaped fluorescent lamp, the inside of the outer tube is filled with a rare gas of several Torr, so it is difficult for the heat generated by the plasma to escape from the inner tube, and the temperature of the inner tube exceeds 100 degrees Celsius. mercury ion diffusion is promoted.

As mentioned above, in a light bulb type fluorescent lamp, the number of mercury ions that reach the inner surface of the inner tube is extremely large, and the temperature of the inner tube is high, making it easy for the mercury ions to enter the inside of the glass tube. is thought to be colored black.

The above-mentioned coloring of the inner tube glass reduces the luminous flux maintenance rate of the lamp. As a preventive measure, for example, JP-A-58-209
As described in No. 046, it has been proposed to form a thin film made of aluminum oxide on the surface of the inner tube glass.

However, there is no mention of once the phosphor film is attached.

When forming a phosphor film on the aluminum oxide thin film mentioned above, a water-soluble binder has been used in recent years, as the phosphor paint uses an organic solvent in which nitrocellulose is dissolved in butyl acetate. . In this case 1, for example, to create a phosphor coating using water-soluble polyethylene oxide, which has excellent flammability, as a binder, if a phosphor film is formed on the aluminum oxide thin film by a normal method, the aluminum oxide thin film and the phosphor The adhesion strength to the film was extremely weak, causing the problem that the phosphor film would fall off.

In addition, in JP-A No. 59-29338, a mixture of calcium pyrophosphate and alumina was applied to the inner surface of the glass tube at 1 d of the inner surface of the bulb.
0.6×10-”mg to 5.0×10-”m per
A curved tube fluorescent lamp has been proposed, which is characterized in that an intermediate coating is applied with a density of g and a phosphor layer is provided thereon.

Whereas in a general annular fluorescent lamp such as FCL30, the tube wall load is about 0.06 W/aJ.

The light bulb-shaped fluorescent lamp has a higher output of 0.15W/cIl. Therefore, as shown in FIG. 2, in order to improve the luminous flux maintenance factor, the first layer coating on the inner surface of the glass tube should be applied at a concentration of 0.1 mg/d to 1.0 mg/d. omg/
It was confirmed that it was necessary to set it to aJ. In this case, the first
Since the amount of the layer deposited increases, the adhesion strength with the phosphor film decreases, resulting in the disadvantage that the phosphor film peels off.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluorescent lamp in which the luminous flux maintenance rate after long-term operation of the fluorescent lamp is improved and the adhesion strength of the phosphor film is improved.

[Summary of the invention]

A first layer of thin film consisting of aluminum oxide and antimony oxide is formed on the inner surface of a non-linear glass tube.

The above object is achieved by providing a second layer of phosphor film thereon.

[Embodiments of the invention]

The present invention will be explained below with reference to the drawings.

FIG. 1 shows an embodiment of the light bulb type fluorescent lamp of the present invention, in which two electrodes 2 are provided on a stem 1, and one end is hermetically sealed to the stem 1 surrounding one of the electrodes 2. The stem 1 includes a pair of inner glass tubes 3 whose other curved ends open near the sealed portion, and an outer glass tube 4 which covers the pair of inner tubes 3 and is hermetically sealed to the stem 1. A screw-in bulb cap or cap bottle (neither of which is shown) is usually attached to the stem side of the outer tube 4 for electrical connection and to hold the lamp.

A thin film 5 made of aluminum oxide and antimony oxide is coated on the inner surface of the inner tube 3.

The thin film 5 is formed by coating the inner surface of the inner tube 3 with a suspension of a mixture of aluminum oxide with an average particle size of about 0.02μ and antimony oxide with an average particle size of about 0.5μ dispersed in water, and applying heated air to the inner surface of the inner tube 3. Dry and form. A phosphor film 6 is deposited on the thin film 5. The phosphor film 6 is made by suspending a europium-activated calcium strontium halophosphate blue phosphor, a terbium-activated lanthanum phosphate green phosphor, and a europium-activated yttrium oxide red phosphor in an aqueous solution of polyethylene oxide, which is a water-soluble binder. This suspension is made cloudy, coated on thin iI5, dried, and then heated to decompose and remove polyethylene oxide.

Furthermore, a trace amount of rare gas and mercury are sealed inside the outer tube 4. The discharge of the fluorescent lamp starts from one electrode 2, passes through the inner tube 3, spreads partially into the outer tube 4 from the opening of the inner tube 3, enters the other inner tube again, is guided to the electrode, and the discharge is generated. In this example, a light bulb type fluorescent lamp was used, with an outer tube having a diameter of 90 mm and a height of 95 mm, an inner tube having an outer diameter of 14 mm, and a length of 125 m.

' Table 1 shows the adhesion strength of the phosphor film when the mixing ratio of aluminum oxide and antimony oxide in the first layer was changed. It is expressed as the weight of the phosphor film that fell off after being dropped horizontally four times in a row.

In addition, the amount of adhesion of the first layer and the phosphor layer is 0, respectively.
, 5 mg/d, and 3 mg/d.

As is clear from Table 1, as antimony oxide is mixed into the first layer of aluminum oxide, the adhesion strength of the phosphor layer improves.

Figure 2 shows the luminous flux maintenance rate after 1000 hours of lighting when the amount of the first layer deposited is changed under the specifications &3 in Table 1 above. It can be seen that the effect is visible.

〔Effect of the invention〕

As mentioned above, in the fluorescent lamp of the present invention, a first layer of a thin film made of aluminum oxide and magnesium oxide is formed on the inner surface of a non-linear glass tube, and a phosphor film is provided on top of the first layer, thereby eliminating mercury ions. This prevents coloring of the inner tube caused by reaching the inner surface of the inner tube, and as a result, it is possible to improve the luminous flux maintenance rate after long-time lighting, and to improve the adhesion strength between the first layer and the phosphor film. You can get the effect of improving.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway sectional view of an embodiment of the light bulb type fluorescent lamp of the present invention. FIG. 2 is a graph showing the relationship between the amount of the first layer deposited and the relative luminous flux maintenance rate.

Claims (1)

[Claims] A fluorescent lamp characterized in that a first thin film made of aluminum oxide and antimony oxide is formed on the inner surface of a non-linear glass tube, and a phosphor layer is provided on top of the first thin film.