JPH0574188B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a power-saving rapid-start type fluorescent lamp having a conductive coating formed on the inner surface thereof, and particularly relates to an improvement of this type of lamp using a rare earth phosphor. be.

[Background of the invention]

In conventional rapid-start fluorescent lamps filled with a gas containing krypton (Kr) as the main component, the resistance of the inner conductive coating was lowered to improve start-up performance. This resulted in drawbacks such as the occurrence of spot-like appearance defects called Hg stains and a decrease in luminous flux maintenance rate due to coloring of the conductive film. As a countermeasure against this problem, a method is known to increase the resistance of the conductive film at the end of the tube, as described in Japanese Patent Publication No. 45-26278. This method had poor startup performance for fluorescent lamps using fluorophores, making it impractical.

[Purpose of the invention]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a rapid-start fluorescent lamp which eliminates the above-mentioned drawbacks.

[Summary of the invention]

In order to achieve the above object, in the present invention,
As a countermeasure against Hg contamination and conductive film discoloration, the resistance at the end of the tube was increased, which conventionally resulted in poor startup performance. By changing the agent, it is possible to provide a power-saving, rapid-start, high-efficiency, high-color-rendering fluorescent lamp that can withstand practical use.

In other words, if a conductive film is formed on the inner surface of the glass tube and 0.01 to 0.1 mg/ ^cm2 of alumina is applied on it, the starting voltage (Vs) will be reduced by about 5%, but this alone is insufficient for practical use. . On the other hand, it was found that the binder added to increase the strength of the fluorescent film affected Vs, and considering its function as a binder, alpha alumina was found to be suitable. It has been found that when alpha alumina is added to the phosphor, starting performance does not deteriorate even if the resistance of the conductive film, especially the resistance of the tube bridge, is increased.

The gist of the present invention is a fluorescent lamp in which a conductive film, an alumina film, and a phosphor film are formed on the inner surface of a glass tube, and a rare gas containing krypton is sealed in the glass tube. The average resistance value of the sexual membrane is 30kΩ/cm ²
or more, and the average value of the resistance value of the conductive coating at the center of the glass tube is 1 kΩ/cm ² or more.
10 kΩ/cm ² or less, the coating amount of the alumina film is 0.01 mg/cm ² or more and 0.1 mg/cm ² or less, and the phosphor film contains a rare earth phosphor and alpha alumina. There are fluorescent lamps.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross-sectional view of a rapid-start type fluorescent lamp according to the present invention, in which a conductive film (hereinafter referred to as NESA film) mainly composed of tin oxide is coated on the inner surface of a glass tube 1.
2 is formed, and an alumina protective film 3 made of γ alumina with an average particle size of 100 μm or less is formed thereon,
A fluorescent film 4 is formed thereon. The fluorescent film 4 is mainly composed of a rare earth phosphor, and 2% by weight of α-alumina is added therein to lower Vs and improve film strength. A small amount of mercury 5 and a few mmHg of a mixed rare gas 6 whose main component is Kr are sealed inside the tube. A test was conducted using a 40 watt Rapid Start fluorescent lamp constructed in this manner. The outer diameter of the tube is 32.5mm, and the total length of the lamp is approximately 1200mm. First, the resistance of the ends A and B of the tube shown in Fig. 3 is 10 kΩ/cm ² , and the center 1/3 is 5 kΩ/cm ² , and the lamp does not contain α-alumina to protect the alumina. The starting voltage was examined by varying the amount of film 3 deposited. The results are shown in FIG. When the alumina coating amount is 0.001 mg/cm ² , the starting voltage (Vs) is the same as when no alumina is applied, but compared to these, when the alumina coating amount is 0.01 mg/cm ² or more, Vs decreases by about 5%. However, the amount of alumina coating
If it exceeds 0.1 mg/cm ² , the luminous flux will deteriorate, that is, the luminous flux maintenance rate will deteriorate, so it is desirable that the upper limit is 0.1 mg/cm ² . Next, set the NESA resistance at the center of the tube to approximately
Keeping 10kΩ/ ^cm2 constant, the average value of tube ends A and B is
It was varied in the range of 10kΩ/cm ² to 50kΩ/cm ² .

Vs is curve C in Figure 4, and Hg staining incidence is curve 5.
This is shown by curve E in the figure. Vs is shown assuming that the ambient temperature is 0°C and the rated voltage is 100%V. Even if the tube end NESA resistance is changed in the range of 10 to 50 kΩ/cm ² , the effect on Vs is about 2.5%V, which is almost no effect.
On the other hand, from Figure 5, the average value of Nesa resistance is 30kΩ/cm ²
Otherwise, Hg stains will occur.

If only halophosphate phosphor is used, 10kΩ/cm ²
Hg contamination is unlikely to occur if it is above a certain level, but with a phosphor film that contains at least 10% rare earth phosphor,
Hg stains are likely to appear. Further, as the content ratio of the rare earth phosphor increases, Vs also increases. Therefore, the average resistance at both ends of the tube, which corresponds to 1/3 of the total length of the tube, must be 30 kΩ/cm ² or more. In addition,
It is preferable that the resistance distribution at the tube end gradually increases toward the tube end.

Next, the NESA resistance at both ends of the tube is set to be constant at approximately 30 kΩ/ ^cm2 , and the NESA resistance at the center 1/3 is set to 0.3~
When the resistance was changed within a range of 20 kΩ/cm ² , Vs became as shown in curve D in Figure 4, and the Hg staining rate became as shown in Figure 5, F.

The resistance in the center has a large effect on Vs, and unless it is less than 10kΩ/cm ² , Vs will exceed the rated voltage at 0°C, making it impractical. On the other hand, from curve F in Figure 5, Hg contamination does not occur if it is 1 kΩ/cm ² . From this, it is appropriate for the center part of the tube to have a resistance of 1 to 10 kΩ/cm ² .

And when alpha alumina is added to the phosphor, Vs
It has the effect of lowering the oxidation rate, and at the same time can increase the film strength. The amount added is preferably 1 to 4% by weight. The reason for this is that if it is less than 1% by weight, the film strength will be weak and is not practical, and if it exceeds 4% by weight, Vs will become saturated and the luminous flux will decrease, making it impractical.

As explained above, the present invention has high Vs and Hg
Fluorescent lamps that are prone to dirt, i.e. fluorescent lamps with 10%
In order to improve both Vs and Hg contamination in rapid-start type fluorescent lamps that contain % or more of rare earth phosphor and whose filler gas is mainly Kr, we have applied alumina protective film, net resistor, and fluorescent film to improve both Vs and Hg contamination. The specifications of additives, etc. are regulated, and the present invention has improved the performance of this type of fluorescent lamp, including its startability and lighting appearance.

〔Effect of the invention〕

As described above, according to the present invention, rapid start type fluorescent lamps containing rare earth phosphors, which have conventionally had poor startability, limited usage conditions, and often had an appearance such as Hg stains, can be made more general. It became possible to improve performance.

Conventionally, in order to prevent Hg contamination, the negative resistance had to be increased, which caused the problem that Vs would become high and the lamp could not be lit at the rated voltage, so it was not put to practical use.However, the lamp of the present invention resolves this contradiction. Therefore, it is possible to put it into practical use. In terms of performance, it has high color rendering and high efficiency (power saving), and has great advantages in terms of lighting economy.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a rapid start type fluorescent lamp according to the present invention, and Figure 2 shows the amount of alumina deposited and Vs.
Figure 3 is an external view of a fluorescent lamp to explain the center part of the tube and the tube ends, Figure 4 is a diagram showing the relationship between the NESA resistance value and Vs, and Figure 5 is a diagram showing the relationship between the NESA resistance value and Vs.
FIG. 3 is a diagram showing the relationship with Hg stain occurrence rate. 1... Glass tube, 2... Nesa film, 3... Alumina protective film, 4... Phosphor film, 5... Mercury, 6...
Filled gas, curve C...Curve showing the relationship between tube end NESA resistance and Vs, curve D...Central NESA resistance and Vs
Curve showing the relationship between curve E... tube end NESA resistance and
Curve showing the relationship between Hg stain occurrence rate, curve F...Curve showing the relationship between central NESA resistance and Hg stain occurrence rate.

Claims (1)

[Scope of Claims] 1. A fluorescent lamp in which a conductive film, an alumina film, and a phosphor film are formed on the inner surface of a glass tube, and a rare gas containing krypton is sealed in the glass tube,
The average value of the resistance value of the conductive coating near the tube end of the glass tube is 30 kΩ/cm ² or more, and the average value of the resistance value of the conductive coating at the center of the glass tube is 1 kΩ/cm ² or more. 10kΩ/ ^cm2 or less,
The coating amount of the alumina film should be 0.01 mg/cm ² or more and 0.1
mg/cm ² or less, and wherein the phosphor film contains a rare earth phosphor and alpha alumina. 2. The fluorescent lamp according to claim 1, wherein the alpha alumina is added in an amount of 1% by weight or more and 4% by weight or less with respect to the phosphor film.