JPH0693353B2 - Fluorescent lamp - Google Patents

Description

Description: [Object of the Invention] (Field of Industrial Application) The present invention relates to a fluorescent lamp, and more particularly to a phosphor coated on the inner surface of a bulb.

(Prior Art) In a fluorescent lamp, a phosphor coating is applied to the inner surface of a bulb so that ultraviolet rays generated from mercury vapor while the lamp is lit are converted into visible rays and emitted.

Calcium halophosphate phosphors have been used in conventional straight tube fluorescent lamps and ring fluorescent lamps for general lighting, but in recent years they have the drawbacks of poor color rendering and optical output. The body tends to be adopted.

The three-wavelength type phosphor is a mixture of blue, green, and red light emitting phosphors having an emission spectrum distribution in a relatively narrow band and used at an appropriate ratio, which greatly contributes to the improvement of color rendering.

Cerium (Ce), terbium (Tb) -activated yttrium silicate phosphor {(Y, Ce, Tb) ₂ O ₃ .SiO ₂ } as a phosphor of the above three-wavelength type phosphor that also emits green light Is known and this is highly efficient. However, this cerium- and terbium-activated yttrium silicate phosphor has a drawback that the light output is relatively large when the lamp is on and the luminous flux maintenance factor is poor.

Therefore, as disclosed in Japanese Patent Publication No. 60-9543, cerium- and terbium-activated lanthanum phosphate phosphors {(La, Ce, T
b) ₂ O ₃ · 0.2SiO ₂ · 0.9P ₂ O ₅ } has attracted attention, and it has been found that both improve the light output and the luminous flux maintenance factor.

(Problems to be Solved by the Invention) By the way, recent fluorescent lamps tend to have high temperatures and high loads. For example, as a fluorescent lamp, bulbs and discharge paths are formed in a meandering bent shape, and such a bent fluorescent lamp is housed in an envelope together with parts for maintaining lighting, A fluorescent lamp device that can replace the conventional incandescent lamp is becoming popular. This type of fluorescent lamp device is also called a compact fluorescent lamp device, and since the fluorescent lamp is housed in the envelope, it is formed in a bent shape to be compact.

In such a fluorescent lamp, since it is housed in the envelope, the heat dissipation is not necessarily good, and therefore the lamp tends to have a high temperature during lighting.

Further, since this kind of bent fluorescent lamp is compactly housed in a limited small space, there is a demand for higher brightness, and therefore a means for increasing the lamp input is adopted, so that the tube wall load is also high. Become.

When the above-mentioned cerium and teribium-activated lanthanum phosphate phosphor is used for the high-temperature and high-load fluorescent lamp as described above, the luminous flux maintenance factor is better than that of the other phosphors described above. However, it does not necessarily reach a satisfactory level, and further improvement is required.

The present invention is intended to provide a fluorescent lamp in which the luminous flux maintenance rate is further improved without lowering the light output when used under high temperature and high load conditions.

[Structure of the Invention] (Means for Solving the Problems) In the present invention, in a fluorescent lamp in which a cerium / teribium-activated lanthanum phosphate phosphor is applied in the bulb, the tube wall load is 1.0 W / cm. ^Two or more are characterized by regulating the cation atomic ratio (La / Ce) of lanthanum and cerium in the range of 2 to 6.

(Operation) According to the present invention, the luminous flux maintenance factor is improved as the cation ratio (La / Ce) is increased. However, an increase in the cation ratio causes a decrease in powder brightness. Therefore, by controlling the cation ratio within the range of 2 to 6, the tube wall load will be 1.0 W / c.
With a lamp of m ² or more, the luminous flux maintenance factor is improved without reducing the light output.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 shows a compact fluorescent lamp device, in which 1 is an envelope. The envelope 1 is composed of a cover 2 and a translucent globe 3, and the cover 2 and the globe 3 are joined to a partition board 4 with an adhesive 5 respectively. A chassis 6 is housed in the cover 2,
The chassis 6 has a base 7 at one end and the partition board 4 is fixed at the other end. Parts for starting and lighting, for example, a ballast 8 and a lighting tube (not shown) are attached to the chassis 6.

A bent fluorescent lamp 9 is housed in the globe 3. The bent fluorescent lamp 9 is a straight tube type glass bulb that is approximately U
The arc-shaped bulb 10 is bent in a letter shape and further bent into a substantially b-shape as shown in FIG. 1. Inside the arc tube bulb 10, electrodes (not shown) are sealed. The inner surface of the arc tube bulb 10 is entirely covered with a phosphor coating 11
Are formed.

The arc tube bulb 10 contains mercury in the form of an amalgam.

The phosphor coating 11 is cerium as a green phosphor,
Ternium-activated lanthanum phosphate phosphor {(La, Ce, Tb) ₂ O
₃・ 0.2SiO ₂・ 0.9P ₂ O ₅ } is used.

And the cation atomic ratio of lanthanum and cerium (La / Ce)
Is specified in the range of 2 or more and 6 or less.

The regulation of the above numerical values is based on an experiment by the present inventors, and the experiment will be described below.

Fig. 2 is a characteristic diagram in which the relationship between the cation atomic ratio (La / Ce) and the luminous flux maintenance factor after 500 hours of lighting was examined by experiments, and the tube wall load (W / cm ² ) was compared as a parameter. It is a thing.

In the figure, (a) is a lamp with a tube wall load of 0.8 W / cm ² ,
(B) is a lamp with a tube wall load of 1.0 W / cm ² , (C) is a tube wall load
It is a 1.4 W / cm ² lamp.

Focusing on the La / Ce ratio in FIG. 2, it can be seen that the luminous flux maintenance factor after 500 hours of lighting improves as the La / Ce ratio increases.

Also, when focusing on the tube wall load, the luminous flux maintenance factor tends to decrease as the tube wall load increases, but when the La / Ce ratio is increased, the luminous flux maintenance factor decreases even if the tube wall load increases. It turns out that In particular, when the tube wall load is 1.0 W / cm ² or more, the luminous flux maintenance factor is greatly improved with respect to changes in the La / Ce ratio, and when the La / Ce ratio is 2.0 or more, the luminous flux maintenance factor is significantly improved. .

When the tube wall load of 0.8 W / cm ² shown in (a) is the same level as the conventional compact fluorescent lamp, La / Ce
Even if the ratio is changed, the change in the luminous flux maintenance factor is 1.0 W / c
less than the m ² or more, and are thus the wall load 1.
It is recognized that if it is less than 0 W / cm ² , there is not much effect even if the La / Ce ratio is increased.

Next, FIG. 3 is a characteristic diagram obtained by examining the powder brightness ratio of the phosphor in relation to the La / Ce ratio. The powder brightness corresponds to the light output, and it was confirmed from the above figure that the powder brightness ratio tends to decrease as the La / Ce ratio increases.

It was confirmed that when the La / Ce ratio exceeds 6, the powder brightness ratio sharply decreases.

From the experimental results shown in Fig. 2 and Fig. 3, it was found that the pipe wall load was 1.
It is recognized that when the La / Ce ratio is restricted to the range of 2 to 6 for 0 W / cm ² or more, the luminous flux maintenance ratio can be kept high without causing a large decrease in the light output.

In FIG. 4, the relationship between the relative illuminance and the tube wall temperature of the lamp using the above phosphor was examined by using the La / Ce ratio as a parameter. (D) is a lamp with a La / Ce ratio of 1.5, (e) is a lamp with a La / Ce ratio of 2.0, and (f) is a La / Ce ratio.
It is a lamp of 4.5.

According to this experiment, when the La / Ce ratio is 1.5 (d), the illuminance is significantly reduced in the high temperature region where the tube wall temperature is 100 ° C or higher. In contrast, lamps (e) and (e) with a La / Ce ratio of 2 or more show a small decrease in illuminance at high temperatures, and it is recognized that the illuminance can be maintained practically without hindrance when used in a high temperature atmosphere. .

The present invention is not limited to the bending type fluorescent lamp in the compact type fluorescent lamp device, and is effectively applied to a fluorescent lamp having a tube wall load of 1.0 W / cm ² or more.

[Advantages of the Invention] As described above, according to the present invention, the tube wall load is 1.0 W / cm ^2.
As described above, there is an advantage that the luminous flux maintenance factor is improved without causing a large decrease in the light output in the fluorescent lamp having a high temperature.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a sectional view of a compact fluorescent lamp device, and FIGS. 2 to 4 are characteristic diagrams showing experimental results. 1 ... Enclosure, 2 ... Cover, 3 ... Glove, 4 ...
Divider, 7 ... Base, 8 ... Stabilizer, 9 ... Fluorescent lamp, 10 ... Bulb, 11 ... Fluorescent film.

Claims (1)

[Claims] 1. A lanthanum phosphate phosphor {(La, Ce, T) activated by cerium and teribium on the inner surface of the bulb.
b) In _{2 O 3 · 0.2SiO 2 · 0.9P} 2 O 5} fluorescent lamp formed by coating a, intended wall loading of 1.0 W / cm ² or more lanthanum and cerium of the phosphor cation Atomic ratio (La / C
A fluorescent lamp characterized in that e) is restricted to a range of 2 to 6.