JPS6145349B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluorescent lamp lighting device that prevents the deterioration phenomenon that occurs in rapid start type fluorescent lamps.

A rapid start type fluorescent lamp, for example, as shown in FIG.
The discharge space 4 within the glass tube 1 is filled with a predetermined amount of mercury and inert gas. However, as shown in Figure 2, this type of fluorescent lamp does not only run for a long time, but also
It has the disadvantage that a blackish brown or yellowish brown discolored area 5 occurs in a range of 10 to 30 cm, and this enlarges to cause a so-called avatar phenomenon, which significantly impairs the appearance. The cause and course of this avatar phenomenon are thought to be as follows. That is, excess mercury first condenses at the coldest point. A voltage is applied between this aggregated mercury and the transparent conductive film 2, and a discharge occurs between the mercury and the film 2 through the phosphor film 3, and the phosphor film 3 is destroyed by the discharge energy. be done. Furthermore, with the addition of the action of free gas (impurity gas emitted from the electrodes and phosphor), dark brown or yellowish brown spots are generated, which gradually expand over the entire area and become the discolored area 5.

Figures 3a and 3b show the tube wall temperature distribution in the tube length direction and the distribution of the potential difference between the discharge potential inside the tube and the transparent conductive coating in a fluorescent lamp with a total length of 120 cm. From figure a, the tube wall temperature is highest at the electrode part at the tube end (80 to 90
℃), and it can be seen that the temperature suddenly drops (approximately 40℃) at a point 10cm to 30cm from the end of the tube, and mercury condenses around this area. However, as is clear from Figure b in this area, there is a large potential difference between the discharge potential within the tube and the transparent conductive film 2, so discharge is likely to occur between the aggregated mercury and the film 2 via the phosphor film 3. be.

The present invention has been made with the aim of solving the problems of the conventional method. A fluorescent lamp lighting device is provided in which a magnetic field generating device is installed in each of the 1/4 ranges, and this magnetic field generating device generates a magnetic field in a direction crossing the discharge path, thereby preventing the generation of discolored parts. This is what was provided.

The present invention will be explained below with reference to illustrated embodiments.
FIG. 4 shows an example in which the present invention is applied to a fluorescent lamp of a lighting device, in which a transparent conductive film 2 and a phosphor film 3 are formed on the inner surface of a glass tube 1, and a predetermined amount of mercury and The fact that it is filled with inert gas is that
It is the same as the conventional one. Reference numeral 6 denotes a magnetic field generating device provided on the outside of the glass tube 1 along the longitudinal direction from both tube ends toward the center of the tube,
Its length is selected to be at least 1/4 of the total length of the glass tube 1, for example, the total length is 120 mm.
For cm fluorescent lamps, it is 30 cm. This magnetic field generator 6 generates a magnetic field in a direction crossing the discharge path, and is constructed by, for example, a permanent magnet made of ferrite having a surface magnetic flux density of 1200 Gauss closely attached to the surface of the glass tube 1. .

Next, to explain the operation of this magnetic field generating device 6, when such a magnetic field generating device 6 is provided,
The tube wall temperature distribution becomes as shown by the solid line A shown in FIG. Note that the dotted line B shows the case of a conventional example without the magnetic field generating device 6. The reason for this is as follows. That is, in the discharge space 4, by applying a magnetic field that crosses the discharge path, electrons therein are accelerated, the electron temperature rises, and the positive column potential gradient rises. On the other hand, since the discharge current is continuous, the power of the magnetic field application section increases, and the temperature of the tube wall at that point increases. Normally, the temperature of the tube wall drops rapidly at about 10 cm from the end of the tube, and the mercury vapor heated near the electrodes diffuses into the center of the tube, where it is rapidly cooled and becomes pseudo-mercury. It adheres to the surface of the phosphor film 3, but by applying a magnetic field in a certain range from the end of the tube to the center as in this example, the power of the object to which the magnetic field is applied increases as described above. As a result, the rapid drop in tube wall temperature at that portion is alleviated, and mercury vapor diffuses to the center of the tube without condensing in that portion, and mercury comes to condense in the center. By the way, the discharge potential inside the tube and the transparent conductive coating 2
The potential difference between the tubes becomes lower toward the center of the tube, as shown in FIG. 3b. Therefore, even if the mercury aggregates, the potential difference between the discharge potential within the tube and the transparent conductive coating 2 at that part is low, and no discharge phenomenon occurs between the aggregated mercury and the coating 2. It has been confirmed that this discharge phenomenon hardly occurs when the potential difference between the discharge potential inside the tube and the transparent conductive coating becomes less than 1/2 of the maximum potential difference, and this potential changes linearly as shown in Figure 3b. Therefore, by providing the magnetic field generating device 6 within a range of at least 1/4 of the total length of the tube from both ends, it is possible to prevent the occurrence of discolored portions that pose a practical problem.

FIG. 6 shows another embodiment of the present invention,
A magnetic field generating device 6 is provided in the main body 7 of the lighting device, and the magnetic field generating device 6 is provided at both ends of the fluorescent lamp 8 that spans 1/4 of the total length, and crosses the discharge path. It is designed to generate a magnetic field in the direction of As in this embodiment, the magnetic field generator 6
If a magnetic field generating device is installed in the fixture body 7, a gap will be created between the fluorescent lamp 8 and the outer wall of the fluorescent lamp 8. Therefore, in order to obtain the same effect as when a magnetic field generating device is directly installed in the fluorescent lamp, a stronger magnetic field must be generated. equipment is required, but the advantage is that conventional rapid-start fluorescent lamps can be used.

As mentioned above, the present invention provides a magnetic field generating device at the tube end of a fluorescent lamp to eliminate a sudden drop in tube wall temperature from the tube end to the center, thereby reducing the internal discharge potential and transparency. This has the advantage that mercury does not aggregate near the end of the tube where the potential difference between the conductive coatings is large, and the deterioration phenomenon in which the phosphor film is destroyed and a discolored area of blackish brown or yellowish brown occurs near the end of the tube can be prevented.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway side view of a conventional fluorescent lamp, Figure 2 is a side view showing the appearance of the same as above when it has deteriorated, and Figures 3a and b are distribution diagrams of tube wall temperature and discharge potential in the tube as above. 4a and 4b are a front view and a partially cutaway side view of a fluorescent lamp according to an embodiment of the present invention, and FIG. 5 is a distribution diagram of the temperature of the tube wall of the same as above. FIG. 6 is a side view of another embodiment. 1 is a glass tube, 2 is a transparent conductive coating, 3 is a phosphor film, 6 is a magnetic field generator, 7 is an instrument body, and 8 is a fluorescent lamp.

Claims (1)

[Claims] 1 Using a rapid-start type fluorescent lamp with a transparent conductive coating coated on the inner surface of a glass tube and a phosphor coated on the coating, light is applied in the longitudinal direction from both ends of the tube toward the center of the tube. along at least 1/4 of the total length
A fluorescent lamp lighting device characterized in that a magnetic field generating device is provided in each of the ranges, and the magnetic field generating device generates a magnetic field in a direction crossing the discharge path.