JP3175285B2 - 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 in which amalgam for controlling mercury vapor pressure and pellets for releasing mercury are accommodated in a thin tube used as an exhaust pipe connected to an arc tube.

[0002]

2. Description of the Related Art In general, a fluorescent lamp emits 185 nm, 254 nm from mercury sealed in an arc tube bulb.
It is known that the lamp emits ultraviolet light such as nm into visible light by a phosphor applied to the inner surface of the arc tube and emits the light to the outside.

In recent fluorescent lamps, the diameter of an arc tube bulb has been reduced for compactness, and the lamp voltage has been increased for higher luminous efficiency. The wall load tends to be higher than conventional fluorescent lamps, and the bulb temperature tends to increase during operation. For this reason, when pure mercury is sealed in the arc tube to serve as a mercury vapor supply source, the mercury vapor pressure in the arc tube exceeds the optimum value, and the luminous flux decreases.

In such a fluorescent lamp having a high tube wall load, it is effective to control the mercury vapor pressure in the tube using a pelletized amalgam having a lower vapor pressure than pure mercury.
It is already in practical use. Such amalgams include mercury (Hg), bismuth (Bi), indium (In),
Alloys such as lead (Pb) and tin (Sn) are used.

The amalgam described above is used in place of pure mercury,
Alternatively, if a mercury-impregnated pellet made of a porous ceramic impregnated with mercury or the like is used, it becomes easy to fill the amount of mercury in a fixed amount according to the amount required during the lamp life.

[0006] Further, since it is difficult to quantitatively enclose liquid pure mercury, the amount of mercury is usually more than required. Therefore, there is a concern that the disposal of used lamps may cause environmental pollution. Alternatively, mercury-impregnated pellets (hereinafter, these are referred to as mercury-releasing pellets or simply pellets) can be filled with mercury in a required amount with a high degree of accuracy. Therefore, there is an advantage that environmental measures are advantageous.

[0007] It is desirable that such a mercury releasing pellet be located at a predetermined location on the arc tube. In a normal fluorescent lamp, the end of the bulb is closed by a stem, and a thin tube is connected to the stem. One of the thin tubes at both ends of the arc tube is used as an exhaust tube. Since such a thin tube has a tip projecting beyond the end of the arc tube, the above-mentioned pellet is stored in the tip of the thin tube.

[0008]

However, when the pellets are accommodated in such a thin tube, if the pellets fall from the thin tube into the discharge region in the bulb, the discharge will heat the pellets, resulting in an excessive amount of mercury release. There is a problem that the vapor pressure becomes too high. In order to prevent such a problem, it is necessary to take measures to prevent the pellet from falling from the thin tube into the valve.

In the prior art, a narrow portion is formed by drawing the middle of the thin tube to prevent the movement of the pellet by the narrow portion, or the opening area of the communication hole for communicating the thin tube with the valve is made smaller than the size of the pellet. And other means were employed.

However, the structure in which the narrow portion is formed in the middle of the thin tube has the following disadvantages. In other words, when this kind of narrow tube is used as an exhaust pipe, if the exhaust pipe is squeezed after the exhaust processing, a problem such as emission of impurity gas is caused. Therefore, it is necessary to form a constricted portion before the exhaust processing. Yes,
However, in this case, since the passage area of the exhaust pipe is reduced, the exhaust speed is reduced, and the exhaust efficiency is reduced.

If the opening area of the communication hole for communicating the exhaust pipe with the valve is smaller than the size of the pellet, the passage area is narrowed in the same manner as described above, so that the exhaust speed is reduced and the exhaust efficiency is reduced.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a lamp in which an exhaust pipe is used as a thin tube for accommodating a mercury release pellet.
An object of the present invention is to provide a fluorescent lamp capable of preventing pellets from falling and eliminating a decrease in exhaust efficiency.

[0013]

According to the present invention, a plurality of communication holes smaller than the size of a pellet are provided between a thin tube and the inside of a valve, and the sum of the opening areas of these communication holes is made larger than the cross-sectional area of the thin tube. It is characterized by having done.

[0014]

According to the present invention, since each communication hole formed between the thin tube and the inside of the valve is smaller than the size of the pellet, the pellet is prevented from falling into the valve. Moreover, since the sum of the opening areas of the plurality of communication holes is larger than the cross-sectional area of the narrow tube, the exhaust speed does not decrease in the exhaust step, and the exhaust efficiency is improved.

[0015]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a bulb constituting an arc tube of a fluorescent lamp, which is formed by a straight glass tube. A phosphor film 2 is formed on the inner surface of the bulb 1, and stems 3, only one of which is shown, are sealed at both ends, and the bulb 1 is closed by these stems 3.

The stems 3 are formed with small tubes 4 and 5 projecting therefrom.
Protruding outward from the end of the. One of the thin tubes 4, 5 also serves as an exhaust pipe, and the tip is sealed off after the exhaust step. An amalgam pellet or a pellet obtained by impregnating a porous ceramic with mercury is accommodated in the thin tube 4, and the amalgam pellet 10 is used in this embodiment. Amalgam pellet 10
Is made of an alloy of mercury (Hg), bismuth (Bi), indium (In), lead (Pb), tin (Sn), or the like, and is accommodated in the small tube 4 in a spherical shape.

The thin tube 4 and the inside of the valve 1 are communicated with each other by a plurality of communication holes 6 opened in the stem 3. In this embodiment, the thin tube 4 and the inside of the valve 1 are electrically connected by two communication holes 6. Each of the communication holes 6 is smaller than the size of the amalgam pellet 10 so as to prevent passage of the amalgam pellet 10. However, the sum of the opening areas of the communication holes 6 is 4 is set to be equal to or larger than the cross-sectional area, that is, the passage area. In addition,
The stem 2 has lead wires 8a and 8
b is hermetically pierced. An inert gas such as argon is sealed in the valve 1 at several Torr.

In the fluorescent lamp having such a configuration, the communication holes 6 for communicating the thin tube 4 and the bulb 1 are formed smaller than the size of the amalgam pellet 10, so that the amalgam pellet 1 accommodated in the thin tube 4 is formed.
0 is blocked and does not fall into the valve 1.
Therefore, during lighting, the amalgam pellet 10 is held in the small tube 4 having a relatively low temperature, and the mercury vapor pressure in the bulb 1 can be maintained at an appropriate pressure.

Moreover, since the sum of the opening areas of the communication holes 6 is larger than the passage area of the thin tube 4,
When the thin tube 4 is used as an exhaust pipe in the exhaust process, there is no fear that the communication hole 6 becomes a resistance to the exhaust flow.

That is, in the evacuation step, evacuation is performed without charging the amalgam pellets 10 into the evacuation pipe. More specifically, the distal end of the exhaust pipe is connected to an exhaust head (not shown). At this time, the amalgam 10 is held by the exhaust head, and in this state, the inside of the valve 1 is exhausted through the exhaust head. By this exhaust, air and impurities in the valve 1 are removed through the communication holes 6 and the small tubes 4. When a predetermined degree of vacuum is reached, an inert gas such as argon and amalgam 1 are introduced into the valve 1 from the exhaust head through the thin tube 4.
Supply 0. Thereafter, the end of the thin tube 4 is sealed off to complete the exhaust process. Therefore, the communication holes 6 ...
Is formed so as to be larger than the passage area of the thin tube 4, so that the communication hole 6 does not become exhaust resistance in the exhaust process, the exhaust speed can be increased, and the efficiency of the exhaust operation can be increased. become. Moreover, such a structure is a stem 3
Since only a plurality of communication holes 6 need to be formed, the production is easy, the productivity is good, and the production can be made at low cost.

The present invention is not limited to the straight tube fluorescent lamp shown in FIG. 3, but may be applied to various bent fluorescent lamps such as U-shaped, double U-shaped, saddle-shaped and ring-shaped. This is possible, and is particularly effective when applied to a fluorescent lamp called a compact type having a shape such as a U shape, a double U shape, and a saddle shape.

[0023]

As described above, according to the present invention, the opening of the communication hole formed between the thin tube and the inside of the valve is made smaller than the size of the pellet, so that the pellet can fall into the valve. Will be blocked. Moreover, since a plurality of such communication holes are provided and the sum of the opening areas is larger than the cross-sectional area of the narrow tube, the communication holes do not become resistance in the exhaust process, and the exhaust speed does not decrease. Will be better. Further, the communication hole has advantages such as easy production, good productivity, and low cost.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a perspective view showing the entire fluorescent lamp of the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Arc tube bulb, 2 ... Fluorescent coating, 3 ... Stem, 4
... capillary tube, 6 ... communication hole, 10 ... amalgam pellet.

Claims (2)

(57) [Claims] 1. A fluorescent lamp in which a mercury-releasing pellet is housed in a thin tube connected to an arc tube bulb and used as an exhaust pipe, wherein a plurality of particles smaller than the size of the pellet are provided between the thin tube and the inside of the bulb. Wherein the sum of the opening areas of the communication holes is larger than the cross-sectional area of the thin tube. 2. The fluorescent lamp according to claim 1, wherein the pellet is an amalgam pellet for controlling a mercury vapor pressure in an arc tube or a pellet in which porous ceramic is impregnated with mercury.