JPH0582697B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a self-ballasted fluorescent lamp.

BACKGROUND OF THE INVENTION Recently, various light bulb-shaped fluorescent lamps have been commercialized as energy-saving light sources to replace incandescent light bulbs.
In these lamps, since the arc tube is built into the outer bulb, the temperature of the arc tube increases excessively compared to that of a normal fluorescent lamp that is lit in a bare state. As a result, the mercury vapor pressure in the arc tube during operation is higher than the optimal level from the luminous flux plane, so
Luminous flux decreases. Therefore, when putting this kind of light bulb-shaped fluorescent lamp into practical use, especially a high-luminous-flux type, how to maintain the mercury vapor pressure at an optimal level is a technical issue.

The amalgam method has been put into practical use as one method for regulating mercury vapor pressure. This is done by adding mercury to indium (In), bismuth-indium (Bi-In), lead-bismuth-tin (Pb-Bi-
This method attempts to regulate mercury vapor pressure to an optimal level even if the temperature of the arc tube rises excessively by making it exist in the form of an amalgam with other materials such as Sn).

Problems to be Solved by the Invention A light bulb type fluorescent lamp containing mercury in the form of amalgam was able to significantly improve the lamp luminous flux compared to one containing only mercury. However, the inventor believes that in such an amalgam-filled fluorescent lamp,
I learned that there are lamps that exhibit a unique phenomenon in which the lamp luminous flux becomes extremely low, albeit with a small probability. For example, the luminous flux of such lamps may be reduced by about 75% compared to that of a normal lamp.

The present invention provides a self-ballasted fluorescent lamp that can prevent the occurrence of such low luminous flux.

Means for Solving the Problems In order to solve the above problems, the inventor first elucidated the phenomenon in which a lamp exhibits low luminous flux, and then studied means for preventing it. As a result, in order to solve the above problem, the lamp should be designed so that the temperature of the amalgam sealed in the arc tube is within a temperature range in which it is completely in a liquid phase during steady operation. It became clear.

Function According to the inventor's analysis, in a specific low temperature range before amalgam completely becomes a liquid phase, amalgam coexists in two states, a liquid phase and a solid phase, and in such a state, the temperature of the amalgam is increased. The mercury vapor pressure showed different values when it was lowered and lowered, and it became clear that the so-called mercury vapor pressure has hysteresis characteristics. The above-mentioned problem of low luminous flux of the lamp occurs when the mercury vapor pressure takes a lower value due to the hysteresis characteristic. That is, the mercury vapor pressure in this case is in a range significantly lower than the optimum level from the luminous flux plane.

As mentioned above, if the amalgam temperature during steady lighting is set within the temperature range where the amalgam is in a complete liquid phase, the hysteresis characteristic of mercury vapor pressure, that is, its decrease, can be prevented and the lamp luminous flux can be maintained near its maximum value. I can do it.

Embodiment As shown in FIG. 1, electrodes 2 and 3 are provided at both ends of a double U-shaped arc tube 1 and held by lead wires 4 and 5 and stems 6 and 7. A phosphor 8 such as a rare earth phosphor is formed on the inner surface. And inside the arc tube 1,
Mercury and argon as a rare gas are sealed at approximately 3.5 Torr. Further, inside the glass capillary tube 9 below the stem 7, a main amalgam-forming material 10 made of Bi-In and a glass rod 11 for regulating the position of the main amalgam-forming material 10 are provided.

Furthermore, the auxiliary amalgam 1 is attached to the lead wires 4 and 5.
2 and 13 are fixed. These are usually made of a metal mesh with indium (In) attached, and their function is to quickly evaporate the mercury reacting with the auxiliary amalgam at the electrode coil heating temperature when starting the lamp, thereby speeding up the rise of the lamp luminous flux. Motsu.

As shown in FIG. 2, the lamp includes an arc tube 1 built into an outer tube globe 14, a case 15 attached to the outer management globe 14, and a base 16 integrated into the case 15. A ballast 17 and a glow starter (not shown) for starting are incorporated inside the case 15.

Now, in the arc tube with the structure shown in Figure 1, a fixed amount of 5.3 mg of mercury is contained inside it, and the composition is Bi67/In33.
65mg, 95mg and 10 of the main amalgam-forming substances
Using lamps each containing 180 mg of amalgam, the behavior of lamp efficiency when changing the main amalgam temperature was investigated in detail. The arc tube 1 used had an outer diameter of about 16 mm and a distance between electrodes of about 280 mm. In this experiment, the amalgam temperature was artificially changed using an external heater, and the lamp efficiency (relative value) was measured when the tube input was constant at 13W. The results are shown in FIG. I found out the following.

(a) Lamp efficiency has two peak regions, a low temperature region and a high temperature region, when the main amalgam temperature is changed. This change in efficiency corresponds to a change in mercury vapor pressure within the arc tube. In other words, in a low-temperature region where the amalgam is in a state in which liquid and solid phases coexist, when the amalgam temperature rises above the peak efficiency point, the mercury vapor pressure will eventually fall below the optimal level from the luminous flux plane. Then, when the amalgam temperature passes the T _A point where it becomes completely liquid phase,
Mercury vapor pressure rises again. In this case, the mercury vapor pressure continues to rise monotonically even after passing the optimum level (peak area of efficiency) from the luminous flux plane.

(b) The peak point of lamp efficiency in the high temperature region is
As the ratio of Bi-In alloy to the amount of mercury enclosed decreases, the temperature shifts to the lower temperature side.

(c) In the above-mentioned low temperature region, there is a specific region in which the lamp efficiency takes different values when the amalgam temperature is increased or decreased. (This is shown by the broken line in Figure 3.) This is also due to the so-called hysteresis characteristic in which the mercury vapor pressure takes different values, and even if the amalgam temperature is lowered past the T _A point. This is because mercury vapor continues to fall without rising. Then, when the mercury vapor pressure reaches the T _B point, it rapidly increases intermittently and returns to the normal level. At present, it is not clear why such a special phenomenon of hysteresis occurs, but it is thought that the temperature point at which the amalgam phase changes is different when the amalgam temperature is raised and when it is lowered. In other words, when the temperature rises, the amalgam changes from a coexisting state of liquid phase and solid phase to a liquid phase state at point T _A , while when the temperature falls, the amalgam in the liquid phase changes to a coexisting state of liquid phase and solid phase at point T _B. It is thought that this will change.

Next, a light bulb-shaped fluorescent lamp was prototyped using the above lamp, in which the length of the glass rod 12 was varied in two levels so that the amalgam temperature was near the peaks of the low temperature region and the high temperature region during steady lighting. for example,
For 180 mg of Bi-In, the center values of the amalgam temperature were designed to be approximately 95°C and 125°C. When these lamps were lit at a rated voltage of 100V,
Approximately 10% of lamps with amalgam temperature specified in the low temperature range are 10% lower than other normal lamps.
It showed ~25% lower luminous flux. On the other hand, none of the lamps whose amalgam temperature was set in a high temperature range exhibited such a peculiarly low luminous flux. In addition, a normal lamp showed an average luminous flux of 40lm at a tube input of 17W.

The inventor investigated the lamp exhibiting the above-mentioned low luminous flux and found that the mercury vapor pressure of this lamp was at the lower value in the hysteresis characteristics shown in FIG. In other words, it is thought that in these lamps, after startup, the amalgam temperature rises above the T _A point and then decreases to below the T _A point. We believe that such historical changes in temperature correspond to the fact that in amalgam-filled lamps, the lamp current becomes abnormally high while mercury evaporates from the auxiliary amalgam after startup, and then decreases to a steady value. It will be done.

On the other hand, as can be seen from FIG. 3, the peak value of the lamp efficiency in the high temperature region is about 2% higher than in the low temperature region, and this rate of increase increases as the lamp input increases. Therefore, from this point of view as well, it can be said that it is more advantageous to specify the amalgam temperature near the peak of the high temperature region rather than the low temperature region.

Incidentally, bulb-shaped fluorescent lamps that use In and Pb-Bi-Sn in addition to Bi-In as amalgam-forming substances may also exhibit similar low luminous flux. This can completely prevent the occurrence of lamps.

Furthermore, the present invention can be implemented not only in a lamp in which a ballast and an arc tube are integrated as shown in FIG. 1, but also in a bulb-shaped fluorescent lamp in which a ballast is separated.

Effects of the Invention As explained above, the present invention provides a self-ballasted fluorescent lamp in which mercury is sealed in the form of amalgam, by defining the amalgam temperature within a temperature range in which the amalgam temperature is completely in a liquid phase during steady operation. The occurrence of lamps with low luminous flux due to the hysteresis characteristics of mercury vapor pressure can be completely prevented. Furthermore, a high level of lamp efficiency can be achieved.

[Brief explanation of the drawing]

Fig. 1 is an enlarged partially cutaway front view of the arc tube of a self-ballasted fluorescent lamp according to an embodiment of the present invention, Fig. 2 is a partially cutaway front view of the same self-ballasted fluorescent lamp, and Fig. 3 is the same. FIG. 3 is a diagram showing the relationship between amalgam temperature and lamp efficiency (relative value) of a self-ballasted fluorescent lamp. DESCRIPTION OF SYMBOLS 1... Arc tube, 2, 3... Electrode, 8... Fluorescent material, 9... Glass capillary, 10... Main amalgam-forming substance, 12, 13... Auxiliary amalgam.

Claims (1)

[Claims] 1. An arc tube with electrodes at both ends, a phosphor formed on the inner surface, and an amalgam-forming substance and a rare gas sealed inside is incorporated into the outer bulb, and the amalgam in the arc tube is completely removed during steady lighting. A light bulb-shaped fluorescent lamp characterized by regulating the temperature to a liquid phase.