JPH03171529A - Manufacture of fluorescent lamp - Google Patents

Abstract

PURPOSE:To obtain satisfied lamp quality with the emission of mercury vapor restrained by providing a constricted part on one side exhaust fine tube to retain a spacer and an amalgam alloy, and making the temperature of the amalgam alloy in the fine tube a melting temperature or below in a heating and exhaust process. CONSTITUTION:Exhaust fine tubes 3 and 4 are outward protrudingly provided in the exhaust work of a double U-shaped fluorescent lamp 1 having an electrode to which an electron radiation substance is applied. A constricted part 5 is provided on the fine tube 4 to retain a spacer 7 and an amalgam alloy 6. Although the lamp 1 is heated in a heating furnace 2, the constricted part 5 is kept at an ordinary temperature, the alloy 6 in not melted, and an exhaust process is finished. Consequently mercury vapor from the alloy 6 is a very small amount, electrode arc discharge is sharply reduced, a decomposition reaction in promoted, an impurity gas such as CO2 is immediately discharged to the lamp outside, an electron radiation substance is activated, and thereby satisfied lamp quality can be obtained.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method of manufacturing a fluorescent lamp.

BACKGROUND OF THE INVENTION A double U-shaped fluorescent lamp having a structure that is compactly folded into three-dimensional dimensions is usually used as a fluorescent lamp of a high-efficiency, long-life compact fluorescent lamp device. This lamp is
Since the lamp is incorporated together with the ballast and starter into a small, sealed outer bulb, the lamp inevitably becomes hot during lighting, and the mercury vapor pressure inside the lamp increases excessively, reducing luminous efficiency. To prevent this, mercury is sealed in the lamp in the form of an amalgam alloy. Various amalgam alloys are known to be sealed to control the mercury vapor pressure, but the efficiency and
Considering all fluorescent lamp functions such as starting performance, indium-based alloys are mainly used. Considering the temperature conditions, the suitable location for providing the amalgam alloy within the lamp is inside the capillary tube. This position maintains the alloy at a temperature that controls the most suitable mercury vapor pressure within the lamp during lamp operation. This temperature is usually close to the melting temperature of the amalgam alloy, approximately 120°C.

Problems to be Solved by the Invention There are two problems in the manufacturing method of a compact fluorescent lamp incorporating this amalgam alloy.

That is, after the double U-shaped fluorescent lamp is bent,
Amalgam alloy particles containing a certain amount of mercury are sealed in advance in one of the tubes, and the tube is tipped off at a length of about 10 m from the sealed end of the glass tube. Thereafter, the lamp is completed as a fluorescent lamp through a heating and exhausting process according to the normal fluorescent lamp manufacturing process. However, during this heating and exhausting process, the glass tube of the lamp is heated to over 400℃, so the amalgam alloy sealed inside the tube also reaches a temperature close to this temperature, which is much higher than its melting temperature of 120℃. At such high temperatures, the alloy melts completely, producing mercury vapor. As a result, not only do mercury particles adhere to the inside of the exhaust system piping, reducing the vacuum level of the system, but also mercury vapor is released inside the lamp during the decomposition exhaust process that activates the electron emitting material coated on the electrodes. Because the filament is full, arc discharge may occur between both ends of the filament coil, lowering the heating temperature and causing incomplete decomposition activation. Lamps manufactured under such adverse conditions are prone to problems such as early blackening near the electrodes, difficulty in starting, and flickering.

Furthermore, as lamps become more compact, the inner diameter of the glass tube becomes smaller and smaller, and the discharge path has more bends. This bent portion is usually reduced in diameter due to manufacturing process considerations. The conductance, which mainly controls the exhaust speed of the lamp, is thought to be proportional to the fourth power of the tube diameter. The inner diameter of the glass tube used in a normal double U-shaped fluorescent lamp is 13.5 mm, which is about 1/2 that of a normal straight tube or ring-shaped fluorescent lamp. Considering that the diameter has been reduced by about 20%, this lamp is very difficult to vent. In particular, this has a significant influence on the decomposition reaction of the electron emitting material on the electrode filament coil located on the opposite side of the exhaust capillary, ie on the closed side. That is, the electrodes of hot cathode fluorescent lamps usually contain B a CO3.
A triple carbonate whose main components are S r CO3 and CaCO3 is coated, and this is thermally decomposed to generate CO2 and becomes an oxide and is activated. Since this decomposition reaction is a reversible reaction, the acceleration will be delayed unless the generated CO2 is quickly discharged. In the current fluorescent lamp manufacturing process, high-speed production is required from the viewpoint of economic efficiency, and there is a natural limit to the time required for this decomposition activation reaction. Therefore, when the conductance of the capillary on the closed side is extremely small compared to that on the exhaust capillary side due to the lamp structure, as in this double U-shaped fluorescent lamp, there is a clear difference in the decomposition reaction of triple carbonate.
Poor decomposition of the electron-emitting substance in the closed-side electrode may occur. In lamps manufactured under such conditions, the decomposition reaction of residual carbonate progresses depending on the electrode temperature during lamp operation, and impurity gases such as CO2 are generated. These impure gases are further converted to C by the energy of ultraviolet rays during discharge.
O immediately combines with mercury in the lamp to form mercury oxide, which adheres to the tube wall and causes blackening, or by increasing the electrode drop voltage and promoting the scattering of electron emitting substances. This has adverse effects such as shortening the life of the electrode.

Means for Solving the Problems The method for manufacturing a fluorescent lamp of the present invention includes electrodes coated with an electron emitting substance at both ends of the tube, and a spacer and a spacer in an exhaust capillary provided protruding from both ends of the tube. In the method for manufacturing a double U-shaped fluorescent lamp with a built-in amalgam alloy, one of the exhaust capillary tubes is provided with a constriction, the spacer and the amalgam alloy are held in the constriction, and the exhaust capillary is directed downward to exhaust air. connected to a circuit, the fluorescent lamp is heated and evacuated while keeping the amalgam alloy below the melting temperature, the exhaust capillary tubes are each tipped off, and the fluorescent lamps are then turned upside down to remove the inside of the exhaust capillary tube. After moving the spacer and the amalgam alloy to the electrode side, the amalgam alloy and the spacer are left in the exhaust tube and the exhaust tube is tipped off again.

During the heating and evacuation process, the amalgam alloy in the evacuation capillary is kept below its melting temperature, so during the decomposition evacuation process to activate the electron emitting material coated on the electrodes, high pressure mercury vapor is released into the lamp. It is possible to avoid the occurrence of undesirable phenomena such as arc discharge when the electrodes are energized and heated. Therefore, the electron emitting material is sufficiently activated within the time given for the decomposition reaction during the evacuation process, and good lamp quality can be obtained.

In addition, since the manufacturing method according to the present invention connects both of the two exhaust thin tubes to the exhaust circuit, the exhaust gas caused by the conductance on the closed side, which had to be taken into consideration when exhausting with only one thin tube in the past, can be avoided. No speed reduction occurs. Therefore, gases such as CO2 generated during the decomposition of triple carbonate, which is commonly used as an electron emitting material, are immediately exhausted, so the decomposition reaction is smoothly promoted, and the blockage side as seen in conventional lamps is eliminated. The electron-emitting substance in one electrode is insufficiently decomposed compared to that in the other electrode, and this causes early blackening near the occluded electrode.
Undesirable phenomena such as shortened life of the electrode due to scattering of electron emitting substances can be suppressed.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram for explaining the method for manufacturing a fluorescent lamp of the present invention. In the same figure, the exhaust work of a double U-shaped fluorescent lamp 1 made of a glass tube with a tube diameter of 15.5+nm and having electrodes (not shown) coated with electron emitting material made of triple carbonate at both ends is as follows: This is carried out using an electric heating furnace 2. Two exhaust thin tubes 3 and 4 are provided to protrude outward from both ends of the glass tube, and a wedge-shaped constriction 5 is formed at the lower center of the exhaust thin tube 4, which allows bismuth, bismuth, A ternary amalgam alloy 6 of indium and mercury and a glass blank rod 7 functioning as a spacer are held. Both the diameter of the amalgam alloy 6 and the diameter of the airless plug 7 are sufficiently smaller than the inner diameter of the exhaust thin tube 4, and the slit width of the constricted portion 5 is also small enough to not interfere with the exhaust speed. and,
The exhaust capillaries 3.4 are each connected to an exhaust circuit 8.

Such a double U-shaped fluorescent lamp 1 is heated in a heating furnace 2,
Although it is heated to a temperature of 00° C. or higher, the constricted portion 5 is located outside the heating furnace 2, thereby keeping this portion at room temperature. Therefore, since the amalgam alloy 6 completes the evacuation process as a solid without being melted, mercury vapor from the amalgam alloy 6 is minute in the heating process for activating the electron emitting substance. As a result, according to the method of the present invention, conventionally, the stem capillary 4 including the empty rod 7 and the amalgam alloy 6 is blown off within a length of Low, and the amalgam alloy part is evacuated using only one capillary tube on one side. Compared to the case where the temperature of the electrode filament coil had risen above its melting point of 106° C., the arc discharge generated between the ends of the electrode filament coil is significantly reduced, and the decomposition reaction is promoted without any hindrance.

In addition, since this double U-shaped fluorescent lamp 1 is exhausted by two exhaust capillary tubes 3.4, the activation of the electron emitting material mainly composed of triple carbonate applied to the electrode coil filaments at both ends is suppressed. Impure gases such as CO2 generated in the thermal decomposition reaction of the lamp are immediately discharged outside the lamp regardless of the low conductance of this lamp structure, so this reaction is accelerated without stagnation, resulting in good lamp quality. be able to.

FIG. 2 (al to (dl) indicates the order of processing of the exhaust capillary in the manufacturing method according to the present invention. Fa in the same figure shows the state immediately before entering the exhaust process, and the inside of the exhaust capillary 4 is The amalgam alloy 6 is held together with the blank rod 7 by the constricted portion 5. Figure fb) shows the state immediately after the exhaust is finished. The exhaust capillary 3 is tipped off short, but the exhaust capillary 4 is tipped off further below the constriction 5. The same figure (Cl shows the state where the top and bottom have been reversed and the empty core 7 and the amalgam alloy 5 have been moved to the electrode side within the exhaust capillary 4. The figure (d) shows the state in which the empty core 7 and the amalgam alloy 5 are moved to the electrode side in this position.
It shows the state in which the exhaust capillary tube 4 is tipped off to a length of ++on and is fully used as a fluorescent lamp.

As a double U-shaped fluorescent lamp, the distance between the electrodes is 280 mm, and the rare gas is 480P of argon.
We obtained a lamp with a lamp current of 270 mA and a power consumption of 16.2 W including ballast loss, and measured various characteristics of a compact fluorescent lamp device built into the outer bulb.We found that there was no flickering. There were no problems such as poor starting or early blackening near the electrodes, and the working characteristics were greatly improved.

Effects of the Invention As explained above, according to the method for manufacturing a fluorescent lamp of the present invention, it is possible to suppress the release of mercury vapor from the amalgam alloy during the heating and exhaust process, and it is possible to suppress the release of mercury vapor from the amalgam alloy, regardless of the decrease in conductance caused by the lamp structure. The thermal decomposition reaction for activating the electron-emitting material coated on the electrodes at both ends of the glass tube can be accelerated without delay by quickly discharging the generated impurity gas. There is no lack of activation or imbalance, so there is no flickering, poor starting, or blackening near the electrodes in the finished compact fluorescent lamp device, and the lamp quality is significantly improved along with improved working characteristics. It is something that can be done.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the method of manufacturing a fluorescent lamp of the present invention, and FIG. 2 ta+(dl) is a process diagram of the method of manufacturing a fluorescent lamp of the present invention. shaped fluorescent lamp, 2...
Heating furnace, 3.4... Exhaust tube, 5...
Neck part, 6... Amalgam alloy, 7...
...No-vacuum rod, 8...Exhaust circuit.

Claims (1)

[Claims] In the method for manufacturing a double U-shaped fluorescent lamp, the double U-shaped fluorescent lamp has electrodes coated with an electron emitting material at both ends of the tube, and a spacer and an amalgam alloy are built into exhaust thin tubes protruding from both ends of the tube. A constriction is provided in one of the thin tubes, the spacer and the amalgam alloy are held in the constriction, and the exhaust thin tube is connected to an exhaust circuit with the exhaust tube facing downward, and the fluorescent light is emitted while keeping the amalgam alloy below the melting temperature. After heating and evacuating the lamp, then tipping off each of the exhaust capillaries, and then turning the fluorescent lamp upside down to move the spacer and the amalgam alloy in the exhaust capillary to the electrode side, A method for manufacturing a fluorescent lamp, characterized in that the amalgam alloy and the spacer are left in the exhaust capillary and the exhaust capillary is tipped off again.