JPH05290808A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To restrain deterioration of an optical flux during a lifetime of a fluorescent lamp which is lighted under a high load condition by forming on an inner surface of a glass bulb a protecting film including mainly titanium oxide coated with fine powder of zirconium oxide and aluminum oxide, and providing a phosphor layer on the protecting film. CONSTITUTION:A titanium oxide particle is coated with zirconium oxide and aluminum oxide in order to obtain a predetermined weight ratio of zirconium oxide, aluminum oxide and titanium oxide. A binder is added into the titanium oxide particle, thus obtaining slurry. The slurry is applied onto an inner surface of a glass bulb 1, thereby obtaining a protecting film 2. A phosphor is applied onto the film 2, followed by drying, thus obtaining a phosphor layer 3. Consequently, deterioration of an optical flux can be reduced during a lifetime of a lamp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp provided with a protective film.

[0002]

2. Description of the Related Art In recent years, in order to save energy and resources of fluorescent lamps, glass bulbs have been made thinner, and in particular, compact fluorescent lamps that have emerged as light sources for replacing light bulbs have economical efficiency, light quality and design. It is recognized for its goodness and is forming a large market. However, since such a fluorescent lamp uses a thin tube bulb and has a compact design, the tube wall load (for example, the input power per unit area) is large, which accelerates the decrease in luminous flux during the life of the fluorescent lamp. There is a problem of causing premature blackening.

Therefore, conventionally, a protective film made of a metal oxide is provided between the glass bulb and the phosphor layer to prevent the blackening of the glass due to the permeation of mercury or ultraviolet rays and suppress the decrease of the luminous flux. Are known. Examples of materials for forming such a protective film include fine powders of titanium oxide, aluminum oxide and the like, organometallic compounds such as alkoxides typified by tetrabutyl titanate, alumina sol and the like.

[0004]

Among the conventionally known protective film materials, the protective film composed of a fine powder of metal oxide generally has a large amount of adhesion, so that the glass bulb is later processed by heat treatment. In such a case, for example, when the bridge bonding process is performed, good bonding cannot be achieved, and when the bending process is performed, the protective film cracks and the performance of the protective film deteriorates, or the phosphor layer falls off. There was a problem of doing. Especially, when the protective film material is made of aluminum oxide, these problems become more remarkable,
The same problem was observed not only in the case of fine powders but also in the case of any material such as an organic aluminum compound or alumina sol.

When an organic metal compound such as an alkoxide is used as the protective film material, an organic metal compound having a large refractive index of an oxide thin film (in this case, a titanium oxide thin film) formed of, for example, tetrabutyl titanate is used. When the material for the protective film is selected, there is a problem that not only the ultraviolet ray but also the visible light transmittance is lowered and the light output is lowered.

The present invention provides a fluorescent lamp provided with a protective film capable of improving the decrease in luminous flux during the life of a fluorescent lamp such as a thin tube fluorescent lamp or a compact fluorescent lamp which is operated under high load conditions.

[0007]

The fluorescent lamp of the present invention comprises:
A protective film containing titanium oxide as a main component, which is surface-coated with fine powder of zirconium oxide and aluminum oxide, is formed on the inner surface of a glass bulb, and a phosphor layer is provided on the protective film.

[0008]

According to the present invention, since the surface of the fine particle titanium oxide forming the protective film is coated as described above, a lamp characteristic with less luminous flux reduction throughout the life can be obtained. Further, the protective film according to the present invention does not cause cracks or detachment of the phosphor layer in various heating processes in the manufacturing process of the fluorescent lamp.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

In the fluorescent lamp of Example 1 of the present invention, as shown in FIG. 2, a protective film 2 and a phosphor layer 3 are formed on the inner surface of a glass bulb 1 for a compact fluorescent lamp using a bridge junction.
Are sequentially formed. FIG. 1 shows an enlarged sectional view thereof.
The glass bulb 1 is filled with mercury and a rare gas. In FIG. 2, 4 is an arc tube top sealing portion, 5
Is an arc tube bridge joint, 6 is an arc tube, 7 is an electrode section, 8
Indicates the base.

The fluorescent lamp of Example 1 of the present invention as described above is manufactured as follows. That is, zirconium oxide 3% by weight, aluminum oxide 7% by weight, titanium oxide 9
Titanium oxide fine particles whose surface was coated with zirconium oxide and aluminum oxide to 0% by weight were slurried into a predetermined concentration with a bead mill using butyl acetate with 2% nitrocellulose as a binder. The protective film 2 is formed by coating the inner surface of the glass bulb 1 and drying it. Next, on the protective film 2, Ba, M
Using the g-aluminate: Eu ²⁺ phosphor and LaPO ₄ : Ce ³⁺ , Tb ³⁺ phosphor and Y ₂ O ₃ : Eu ³⁺ phosphor at a mixing ratio (% by weight) of 16:43:41 The butyl acetate-based phosphor suspension described below is applied and dried to form a phosphor layer 3 having an adhesion amount of 4.5 mg / cm ² . Thereafter, a compact fluorescent lamp equivalent to 27 W was manufactured by a usual method including heat treatment such as sealing of the top portion and bridge joining.

Further, for comparison, alumina sol 0.
A compact fluorescent lamp (Reference Example 1), which was coated with a 5% aqueous solution and dried to form a protective film, and a compact fluorescent lamp having only a phosphor layer (Reference Example 2) were simultaneously prepared. In the fluorescent lamp of Reference Example 1, the arc tube was heat-processed to some extent, and the sealing of the top portion and the joining of the bridge portion could not be performed satisfactorily. Was not obtained.

On the other hand, in the compact fluorescent lamp having the protective film according to the present invention, no processing defect was observed even when the amount of the protective film attached was further increased.

Table 1 shows the initial luminous flux (luminous flux after 100 hours of lighting), the luminous flux after 1000 hours of illumination, and the luminous flux maintenance factor of these lamps.

[0015]

[Table 1]

As is apparent from Table 1, Example 1 of the present invention
The initial luminous flux of the lamp and the luminous flux maintenance rate after 1000 hours of lighting were significantly improved to 213 lm and 6.3%, respectively, as compared with Reference Example 2, and the characteristics equal to or higher than those of Reference Example 1 were obtained. I understand that

As described above, the protective film according to the present invention can exhibit excellent performance in terms of lamp characteristics during its life, and has a stable advantage even in the heating process in the lamp manufacturing process.

Next, as a second embodiment of the present invention, an example applied to a ring-shaped fluorescent lamp corresponding to 30 W will be shown.

The protective film 2 and the phosphor layer 3 are deposited as follows.
It is similar to the case of the above-mentioned first embodiment, and the forming method is also the same. Also, the phosphor used has the same composition as before,
The adhered amount was set to 3.5 mg / cm ^2, and a ring-shaped fluorescent lamp was produced by a usual method including bending thereafter.

For comparison, a fluorescent lamp (conventional example) having a calcium halophosphate phosphor as the first layer (corresponding to the protective film 2 in FIG. 1) was also prepared. Table 2 shows the initial luminous flux of these fluorescent lamps and the luminous flux and luminous flux maintenance rate after 1000 hours of lighting.

[0021]

[Table 2]

As is clear from Table 2, Example 2 of the present invention
The initial luminous flux of the lamp is not so different from the conventional example, but it can be seen that the luminous flux maintenance rate after 1000 hours of lighting is improved by about 1% compared to the conventional example. From this, it can be said that the protective film according to the present invention has an excellent function as a protective film as compared with the conventionally known calcium halophosphate phosphor coating.

As described above, the improvement in performance of the fluorescent lamp of the present invention is particularly remarkable in the compact fluorescent lamp, but is also recognized in general fluorescent lamps.

[0024]

As described above, in the fluorescent lamp of the present invention, the inner surface of the glass bulb is formed with a protective film containing titanium oxide as a main component, which is surface-coated with fine powder of zirconium oxide and aluminum oxide. Since the phosphor layer is formed on the top of the phosphor layer, it is possible to obtain the characteristic that the luminous flux is less likely to decrease throughout the life. In addition, since the protective film according to the present invention does not adversely affect the heating process in the manufacturing process of the fluorescent lamp, it is particularly applicable to the fluorescent lamp manufactured by using the bridge junction or the bending process. The luminous flux drop can be reduced throughout the life of the.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part of a fluorescent lamp that is an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of the same.

[Explanation of symbols]

 1 Glass bulb 2 Protective film 3 Phosphor layer

Claims (1)

[Claims] 1. A glass bulb is provided with a protective film containing titanium oxide as a main component, the surface of which is coated with fine powder of zirconium oxide and aluminum oxide, and a phosphor layer is provided on the protective film. Fluorescent lamp to do.