JP2912734B2 - 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 lamp having a protective film.

[0002]

2. Description of the Related Art In recent years, the use of fluorescent lamps in glass tubes has been advanced from the viewpoint of energy saving and resource saving.
The compact fluorescent lamp, which has emerged as a light source for replacing a light bulb, has been recognized for its economic efficiency, light quality and good design, and is forming a large market. However, such a fluorescent lamp uses a thin tube bulb and has a compact design, so that the tube wall load (for example, input power per unit area) is large. There is a problem of causing blackening.

Therefore, conventionally, by providing a protective film made of a metal oxide between the glass bulb and the phosphor layer, the blackening of the glass due to the penetration of mercury or ultraviolet rays is prevented and the luminous flux decline is suppressed. It is known.

[0004]

Among the known protective film materials, a protective film composed of a fine powder of a metal oxide generally has a large amount of adhesion. Therefore, the glass bulb is later processed by heat treatment. For example, when performing bridge bonding, good bonding cannot be achieved, and when performing bending, the protective film is cracked and the performance of the protective film is reduced, or the phosphor layer is dropped. There was a problem of doing. For example, Japanese Patent Publication No. 41-11628 discloses a fluorescent lamp in which a protective film made of titanium or alumina having a particle size of 100 μm or less is formed between an inner surface of a bulb and a light emitting layer. However, such a technique has an excellent effect when applied to a straight tube fluorescent lamp, but when applied to a ring-shaped fluorescent lamp, the phosphor layer falls off at the time of bending in the lamp manufacturing process. Is not achieved. As described above, the effects of the protective film mainly composed of alumina, which is obtained when applied to a fluorescent lamp, to reflect ultraviolet rays and to prevent blackening of a glass bulb, etc., have been well known. There has been no known configuration of a protective film capable of maintaining its effect even after a process such as bending or bridge joining in a manufacturing process.

The present invention is to provide a fluorescent lamp which can suppress a reduction in luminous flux during its life even if it is a ring-shaped fluorescent lamp or a compact fluorescent lamp which is bent or bridge-joined in a lamp manufacturing process.

[0006]

In order to solve this problem, a fluorescent lamp according to the present invention has a protective bulb comprising a mixture of fine particles of alumina and an alkaline earth metal borate-phosphate fine powder on the inner surface of a glass bulb. A film is formed, and a phosphor layer containing lanthanum phosphate powder is provided on the protective film.

[0007]

According to this structure, a characteristic in which the luminous flux is less reduced throughout the life can be obtained. In addition, the protective film according to the present invention does not cause defects such as cracking or falling off of the phosphor layer in various heating processes in a fluorescent lamp manufacturing process due to interaction with lanthanum phosphate mixed into the phosphor layer. In addition, since it is almost transparent and does not reduce the transmittance of visible light, the decrease in light output due to the provision of the protective film is extremely small.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fluorescent lamp according to an embodiment of the present invention has a structure in which four straight tube-shaped glass bulbs 1 are bridge-joined as shown in FIG. Protective layer 2 made of a mixture of silica and alkaline earth metal boric acid-phosphate fine powder, and a phosphor layer containing 15.0% by weight of lanthanum phosphate powder with respect to the phosphor on protective film 2 3 are formed. 2, reference numeral 4 denotes an arc tube top sealing portion, 5 denotes an arc tube bridge joint portion, 6 denotes an arc tube, 7 denotes an electrode portion, and 8 denotes a base socket.

The fluorescent lamp according to the embodiment of the present invention is as follows.
It is produced as follows. That is, first of all, 3%
(Ca, Ba) O in 1 liter of colloid solution containing silica
・ B_TwoO _Three・ P_TwoO_FiveAlkaline earth metal boric acid-phosphate fines
After mixing 10 g of the powder, the mixture is diluted with ethanol.
To make a 0.5% ethanol solution. Next, the gala
On the protective film 2 formed on the inner surface of the valve 1, Ba, Mg-Al
uminate: Eu²⁺Phosphor and LaPO_Four: Ce³⁺, Tb³⁺ Phosphor and Y_TwoO_Three: E
u³⁺Phosphor and LaPO_FourLanthanum phosphate powder represented by
1: 38: 36: 15 by weight of butyl acetate
A phosphor suspension as a medium is applied, dried and attached
Is 4.5mg / cm^TwoIs formed. Since then, top
Ordinary people including heat treatment such as part sealing and bridge joining
27W compact fluorescent lamp with the structure shown in FIG.
A pump was made.

Further, for comparison, alumina sol 0.5%
A compact fluorescent lamp (Reference Example 1), which was coated with an aqueous solution and dried to form a protective film, and a compact fluorescent lamp provided only with a phosphor layer (Reference Example 2) were produced simultaneously. In addition, in the fluorescent lamp of Reference Example 1, there is not a little problem in heating the arc tube, and the sealing of the top portion and the joining of the bridge portion cannot be performed satisfactorily. Was not obtained. On the other hand, a protective film 2 made of a mixture of fine particles of alumina and alkaline earth metal boric acid-phosphate fine powder is formed, and lanthanum phosphate powder of 15.0% by weight based on the phosphor is formed on the protective film 2. In the case of the compact fluorescent lamp provided with the phosphor layer 3 containing no, no processing failure was observed even when the amount of adhesion was further increased.

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

[0013]

[Table 1]

As apparent from Table 1, the initial luminous flux of the lamp according to the present invention and the luminous flux maintenance factor after 1000 hours of operation are significantly improved to 133 lumens and 7.6%, respectively, as compared with Reference Example 2. Also, it can be seen that the same or better characteristics are obtained as compared with Reference Example 1. in this way,
The protective film formed according to the present invention can improve the initial luminous flux of the lamp by interacting with the lanthanum phosphate powder mixed in the phosphor layer, and can exhibit excellent performance in terms of lamp characteristics during the lifetime. It has a stable advantage even in the heating process in the lamp manufacturing process.

Next, a series of 30 W-equivalent ring-shaped fluorescent lamps in which the amount of the lanthanum phosphate powder added to the phosphor layer 3 was changed were manufactured by an ordinary method including bending. First, in a prototype lamp in which the alkaline earth metal boric acid-phosphate fine powder is not added to the protective film 2, a conventionally known phosphor layer falls off during bending in the lamp manufacturing process,
This could not be solved even if the amount of lanthanum phosphate powder added to the phosphor layer 3 was increased. When the amount of the alkaline earth metal boric acid-phosphate fine powder added to the protective film 2 is 20% by weight or more based on the fine-particle alumina,
It is practically desirable that the luminous flux maintenance factor during the life of the lamp is reduced, and that the addition amount is 10% or less. Further, the addition amount is more preferably in the range of 0.1 to 3% by weight.

On the other hand, the amount of lanthanum phosphate powder added to the phosphor layer 3 is preferably in the range of 0.5 to 20.0% by weight based on the phosphor, and as shown in FIG. And the interaction with the protective film 2 described above
In addition, the adhesive strength of the phosphor layer 3 was clearly improved. However, it was found that when the addition exceeds 20.0% by weight, the lamp luminous flux is greatly reduced due to the incorporation of lanthanum phosphate powder, which is a non-light emitting substance, into the phosphor, which is inappropriate.

The present invention can be applied not only to a bridge-type fluorescent lamp and a ring-type fluorescent lamp but also to a straight tube fluorescent lamp and the like.

[0018]

As described above, the fluorescent lamp of the present invention has a protective film made of a mixture of fine particles of alumina and alkaline earth metal borate-phosphate fine powder formed on the inner surface of a glass bulb. Since the phosphor layer containing the lanthanum phosphate powder is formed on the protective film, the initial luminous flux of the lamp can be improved, and the adhesive strength between the protective film and the phosphor layer can be increased. Characteristics with little reduction are obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a fluorescent lamp according to an embodiment of the present invention.

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

FIG. 3 is a diagram showing the relationship between the amount of lanthanum phosphate added to a phosphor layer and the initial luminous flux of a lamp.

Continuation of the front page (56) References JP-A-62-176042 (JP, A) JP-A-61-2556 (JP, A) JP-A-63-955 (JP, A) JP-A-61-27055 (JP) JP-A-57-96080 (JP, A) JP-A-57-98970 (JP, A) JP-A-2-40854 (JP, A) JP-A-5-13047 (JP, A) 36-14022 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01J 61/35 H01J 61/46

Claims (2)

(57) [Claims] 1. A protective film comprising a mixture of fine particles of alumina and an alkaline earth metal borate-phosphate powder is formed on the inner surface of a glass bulb, and a phosphor layer containing a lanthanum phosphate powder is formed on the protective film. A fluorescent lamp comprising: 2. The fluorescent lamp according to claim 1, wherein the amount of the lanthanum phosphate powder is in the range of 0.5 to 20.0% by weight based on the phosphor.