JPH08236071A - Electrode for fluorescent lamp and its manufacture and manufacture of fluorescent lamp using its electrode - Google Patents

Abstract

PURPOSE: To lengthen the service life of a lamp by laying an electron emitting substance short in time up to becoming an actuating temperature of emitting a normal thermoelectron on a multiple coil filament. CONSTITUTION: After a mixture 4 containing metallic tantalum, a barium peroxide and an organic binder is laid on a multiple coil filament 1, the multiple coil filament 1 is heated in a vacuum by carrying an electric current, and an electron emitting substance 3 containing tantalic acid barium is laid and formed on a surface of the multiple coil filament 1. Since the tantalic acid barium has heat conductivity of about 5 to 7 times a composite oxide of alkaline earth metal, heat capacity in a condition of being laid on the multiple coil filament 1 is reduced, and time up to becoming an actuating temperature of emitting a normal thermoelectron is lengthened, and sputtering is reduced, and the service life is lengthened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp electrode comprising a multi-coil filament coated with an electron emissive material,
And a method for manufacturing the same, and a method for manufacturing a fluorescent lamp using the electrode.

[0002]

2. Description of the Related Art In general, the life of a fluorescent lamp is determined by the fact that the electron emissive material filled in the primary coil of the tungsten multi-coil filament evaporates, scatters and is consumed at the time of starting and operating the lamp. It

As a multi-coil filament,
A double coil filament, a so-called triple coil filament in which a thin wire is loosely wound around the double coil filament, a block coil filament in which a coil is wound in three layers, and the like have been put into practical use. And, as the electron emissive material, zirconium oxide is several wt%
A complex oxide of alkaline earth metals (barium, strontium, calcium) containing is used, and as a result of various improvements in recent years, the rated life of the fluorescent lamp is, for example, 6000 hours for FL10 and 8500 hours for FL20SS. , 12 for FL40SS and FLR40S
A life of 000 hours is becoming available.

FIG. 3 shows an example of the above-mentioned conventional fluorescent lamp electrode disclosed in JP-A-6-176735. The fluorescent lamp electrode is formed by winding a tungsten wire. A double coil filament, which is a multi-coil filament 1, is pinched to the lead-in wire 2, and the double coil filament 1 is filled with an electron emissive material 3 having the following composition up to the final winding portion of the double coil filament 1. is there.

The composition of the electron emissive material is as follows: barium carbonate, 29 wt% strontium carbonate, 27 wt% calcium carbonate, 15 wt% zirconium oxide, 9 wt% nitriding Boron powder: 5 wt% Metal tantalum powder: 15 wt% The above three kinds of carbonates are not individual, but the composite carbon dioxide synthesized in the above weight ratio. Used in salt form.

[0006]

However, in recent years when the global environmental problems are becoming apparent, the above rated life is never satisfied from the viewpoint of resource saving and environmental pollution due to discharge of mercury enclosed in the lamp. However, it has been desired to further extend the life of fluorescent lamps.

By the way, the lighting life of the fluorescent lamp becomes shorter as the number of times of blinking increases because the electron emissive material is consumed more during starting than during lighting. Generally, it is said that one blinking shortens the life of about 30 minutes to 1 hour 30 minutes.

This is because the electron emissive material filled in the filament of the fluorescent lamp has a certain amount of heat capacity, so that ions due to a high electrode drop voltage are generated until the normal operating temperature for thermionic emission is reached. This is because the electron emissive material is scattered and consumed by so-called sputtering due to the impact. At this time, of course, the filament is also damaged by the spatter and, in the worst case, is broken. Also, the scattered electron emissive material and the damaged coil are
This causes blackening of the tube wall of the lamp and reduction of the luminous flux, which also causes a shortening of the lamp life.

Also in the fluorescent lamp electrode shown in FIG.
Since the electron emissive material 3 filled in the multi-coil filament 1 contains the complex oxide of alkaline earth metal and has a certain heat capacity as described above, the normal operating temperature for thermionic emission is obtained. However, there is a problem that the life is short from the above-mentioned point of view.

The present invention has been made in view of the above problems, and an object of the present invention is to coat a multi-coil filament with an electron emissive material that takes a short time to reach a normal thermoelectron emission operating temperature. To provide an electrode for a fluorescent lamp to be worn, and another object is to provide a method for manufacturing the electrode for a fluorescent lamp, and yet another object is to It is an object of the present invention to provide a method for manufacturing a fluorescent lamp using an electrode for a fluorescent lamp.

[0011]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a fluorescent lamp electrode comprising a multi-coil filament 1 coated with an electron-emitting substance 3 in order to solve the above problems. In the above, the multi-coil filament 1 is coated with an electron emissive material 3 containing barium tantalate.

Further, the invention according to claim 2 is characterized in that, in the fluorescent lamp electrode according to claim 1, alumina is added to the electron-emitting substance 3.

Further, in the invention according to claim 3, in the fluorescent lamp electrode according to claim 1 or 2, the electron-emitting substance 3 is carried in proximity to the multi-coil filament 1. The guide 8 is provided.

Further, in the invention according to claim 4, there is provided the method for manufacturing an electrode for a fluorescent lamp according to any one of claims 1 to 3, wherein the multi-coil filament 1 comprises: After depositing a mixture 4 containing metallic tantalum, barium peroxide and an organic binder, the multi-coil filament 1 is electrically heated in a vacuum to heat the multi-coil filament 1 to emit an electron-emitting substance containing barium tantalate. 3 is formed.

According to the invention of claim 5, there is provided a method of manufacturing a fluorescent lamp using an electrode for a fluorescent lamp according to any one of claims 1 to 3, wherein the multiplex method is used. A fluorescent lamp electrode is manufactured by depositing an electron emissive substance 3 containing barium tantalate on the coil filament 1, and then the fluorescent lamp electrode is attached to both ends of the bulb 6a of the fluorescent lamp 6. is there.

[0016]

According to the present invention, the barium tantalate has a thermal conductivity about 5 to 7 times that of the alkaline earth metal composite oxide. The heat capacity in the state of being attached to the multi-coil filament 1 becomes small, and the time until the normal operating temperature of thermionic emission is reached becomes long, so that the spatter becomes small.

Further, in the invention described in claim 2, in addition to the function of the electrode for a fluorescent lamp according to claim 1, alumina is used between particles of barium tantalate, or barium tantalate and the multi-coil filament 1. By interposing between them, the adhesion of barium tantalate to the multi-coil filament 1 is improved.

Further, in the invention described in claim 3, in addition to the function of the fluorescent lamp electrode described in claim 1 or 2, the number of the guides 8 is larger than that in the case where only the multi-coil filament 1 is used. Hold twice as much electron emissive material 3.

Further, in the invention of claim 4, the multi-coil filament 1 is coated with the mixture 4 containing tantalum metal, barium peroxide and an organic binder, and then the multi-coil filament 1 is vacuumed. Since the electron-emitting substance 3 containing barium tantalate is formed by being electrically heated in the inside, the surface of barium tantalate becomes extremely porous.

In the invention according to claim 4, the fluorescent lamp electrode is manufactured by depositing the electron emitting substance 3 containing barium tantalate on the multi-coil filament 1 to manufacture the fluorescent lamp electrode. Since the fluorescent lamps are mounted on both ends of the fluorescent lamp, the reaction of the mixture 4 of barium peroxide and tantalum metal powder is not affected by the temperature rise when the stem 5 is sealed. In the valve 6a in the vicinity of the electrode
Does not adhere to the inner wall and turn black.

[0021]

FIG. 1 shows a first embodiment of a fluorescent lamp electrode of the present invention, a method of manufacturing the same, and a method of manufacturing a fluorescent lamp using the electrode. , The multi-coil filament 1, the lead-in wire 2, the electron emissive material 3, and the stem 5, and are attached to both ends of the bulb 6 a of the fluorescent lamp 6.

The multi-coil filament 1 is, for example, a double-coil filament formed by winding a tungsten wire, and its surface is coated with an electron emissive material 3 made of barium tantalate. It is pinched by the lead-in line 2. The lead-in wire 2 is embedded in stems 5 mounted on both ends of the bulb 6a of the fluorescent lamp 6, and the lamp caps 6 mounted on both ends of the bulb 6a.
It is connected to the pin 6c of b.

The fluorescent lamp electrode having such a structure is manufactured as follows. That is, first, to the double coil filament 1 which is a multi-coil filament, the mixture 4 having a weight composition ratio of barium peroxide ... 67 wt% metal tantalum powder ... 33 wt% is added to zirconia having a diameter of several mm. Nitrocellulose which is an organic binder together with the ball is 5 wt.
% Butyl acetate solution, crush and stir with a ball mill for 10 hours or more, and the resulting slurry is filled up to the final winding portion of the double coil filament 1 as shown in FIG. To wear. At this time, it is desirable that the particle size of the metal tantalum powder be about several μm in order to ensure the reaction with barium peroxide.
˜3 μm. The mixing ratio of the mixture 4 of barium peroxide and tantalum metal powder is allowed to vary by about ± 20%.

Next, the entire fluorescent lamp electrode including the stem 5 is placed in a vacuum (a vacuum container or the like is not shown), and the multi-coil filament 1 is electrically heated so that metal tantalum and barium peroxide are removed. A so-called activation treatment is performed in which the reaction is performed and barium tantalate is synthesized on the multi-coil filament 1.

At this time, a shielding plate 7 is provided between the multi-coil filament 1 and the stem 5 to prevent the mixture 4 scattered during the heating reaction from adhering to the stem 5. In addition, the synthesis of barium tantalate is performed in a vacuum in order to prevent the multi-coil filament 1 from being oxidized during the heating reaction, but it can be synthesized in an inert atmosphere other than the vacuum while preventing the oxidation. Is. However, in an inert atmosphere, the reaction of barium tantalate is likely to be non-uniform, and therefore it is most desirable to carry out electric heating in vacuum while constantly exhausting with a vacuum pump. Needless to say, the activation treatment may be performed by holding only the multi-coil filament 1 in a vacuum by another means instead of the entire fluorescent lamp electrode.

The electrodes for fluorescent lamps thus coated with barium tantalate are attached to both ends of a glass bulb 6a having an inner wall coated with a phosphor 6d, as shown in FIG. 1 (c). Then, the fluorescent lamp 6 is manufactured through the same manufacturing process as that of a normal fluorescent lamp, and a discharge gas composed of mercury and argon is enclosed in the bulb 6a to form the fluorescent lamp 6.

It should be noted that barium tantalate is relatively stable in air, and even if it is left in the air for several hours, its characteristics do not cause any particular problem, but exposure to air after activation is If possible, it is desirable to set the time within about 1 hour.

In the case of a normal fluorescent lamp, after the electrodes for the fluorescent lamp are mounted on both ends of the glass bulb in advance, the emissive material is activated while being evacuated. In the above method, the activation process is performed in vacuum in advance, and the fluorescent lamp electrode is attached to the bulb 6a to manufacture the fluorescent lamp 6 for the following two reasons.

One of them is that since the reaction start temperature of the mixture 4 of barium peroxide and metal tantalum powder is as low as 300 to 400 ° C., the temperature in the vicinity of the electrode rises when the stem 5 is sealed, and the mixture 4 becomes This is because it fires (reacts). If this reaction occurs when the stem 5 is sealed, the filament is oxidized because the fluorescent lamp electrode is in the atmosphere, and the desired characteristics cannot be obtained. The other is to prevent the mixture 4, which is partly scattered, from adhering to the inner wall of the valve 6a near the electrode and blackening during the heating reaction of barium peroxide and metallic tantalum.

With this structure, barium tantalate has a thermal conductivity of about 5 to 7 times that of the alkaline earth metal complex oxide in the present embodiment. The heat capacity in the adhered state becomes small, the time until the operating temperature of normal thermionic emission is reached becomes long, the spatter becomes small, and the life can be extended. Further, the inventor of the present application discovered that barium tantalate formed by being electrically heated in a vacuum is extremely porous when its surface state is observed with a microscope. Then, the porous surface state facilitates the formation of so-called hot spots, which are cathode spots generated during discharge,
It is also presumed that the damage of the multi-coil filament 1 and the electron emissive material 3 due to the ion bombardment is alleviated.

Further, in manufacturing the fluorescent lamp 6,
After the electron-emitting substance 3 containing barium tantalate is applied to the multi-coil filament 1 in advance to manufacture a fluorescent lamp electrode, the fluorescent lamp electrode is attached to the fluorescent lamp 6.
The reaction of the mixture 4 of barium peroxide and the metal tantalum powder is not affected by the temperature rise when the stem 5 is sealed, because the valves 6a are attached to both ends of the valve 6a. And partly scattered mixture 4
However, it does not adhere to the inner wall of the bulb 6a near the electrode and turn black. The present inventor manufactured the fluorescent lamp 6 of FL40SS equipped with the fluorescent lamp electrode in the present embodiment,
As a result of conducting a short-term blink comparison test of 10 seconds on and 50 seconds off using a conventional fluorescent lamp of the same kind and an inverter ballast of instantaneous lighting, the average number of blinks until each 10 fluorescent lamps came to a defect It was confirmed that the fluorescent lamp of the barium tantalate electrode of the present example has a flashing life of 65300 times and that of the conventional alkaline earth metal oxide electrode of 17800 times, which is three times or more the blinking life.

Also, as a second embodiment of the present invention, in the first embodiment, 5 to 10 wt% of alumina is added to the mixture 4 of barium peroxide and metallic tantalum powder, and this is used as a multiple coil. There is one in which a double coil filament which is the filament 1 is filled and activated in the same manner as in the first embodiment, and the electron emissive substance 3 containing barium tantalate is adhered to the surface thereof. .

That is, when the multi-coil filament 1 has a high holding force for the adhered substance like a triple coil, it is unlikely to cause a problem, but in the case of a double coil, there is a concern that it may fall off. After activation treatment, barium tantalate has an extremely porous surface shape and is brittle. Therefore, alumina is added to enhance the adhesion of barium tantalate.

With this structure, in the fluorescent lamp electrode and the fluorescent lamp using the electrode according to this embodiment, in addition to the effect of the first embodiment, when the alumina reacts with the heating reaction, A part of them is melted to intervene between the particles of barium tantalate or between the barium tantalate and the multi-coil filament 1 to increase the adhesive force, and the adhesion of barium tantalate to the multi-coil filament 1 is improved. .

As a result of performing a vibration test on the fluorescent lamp electrode in this embodiment, even in the case of a double coil,
It was confirmed that the electron emissive material 3 did not drop off significantly and that there was no practical problem.

FIG. 2 shows a third embodiment of the fluorescent lamp electrode of the present invention.
The first embodiment is different from the first embodiment in that the two parts of the multi-coil filament 1 which are fixedly held to the lead-in wire 2 and have a substantially U-shaped cross section are provided. The point is that the guide 8 is provided to carry the electron emissive material 3, and the other points are configured similarly to the first embodiment, and
It is manufactured in the same way.

The guide 8 having a substantially U-shaped cross section is preferably made of a metal having a high melting point and conductivity. For example, the guide 8 is made of a molybdenum plate. The two guides 8 are fixed to the pair of lead-in wires 2 so as not to short-circuit at the lower central part of the multi-coil filament 1, that is, there is a gap between the tips, and are formed in a U-shape. A larger amount of the electron emissive material 3 is carried in the formed portion.

Because of the above structure, the guide 8
As a result, the amount of barium tantalate, which is an electron emissive substance, is held 2 to 3 times as compared with the case where the guide 8 is not provided, and it is possible to improve the lighting life in a use state in which blinking is relatively small. The fluorescent lamp in the present embodiment is currently undergoing a comparative lighting test, but the life in the middle is 1.5 times that of the conventional lamp, and the lighting is still continuing.

In each of the above embodiments, the multi-coil filament 1 has been described as a double-coil filament, but the present invention is not limited to this and may be another filament such as a triple-coil filament. Of course.

[0040]

As described above, according to the invention described in claim 1, the rectangular wave voltage is applied between the hot cathodes as described above. Therefore, according to the invention described in claim 1, Barium tantalate has a thermal conductivity about 5 to 7 times that of alkaline earth metal composite oxides, so the heat capacity when applied to a multi-coil filament is small, and normal thermionic emission behavior is achieved. It takes longer to reach the temperature, less spatter, and longer life can be achieved.

According to the invention of claim 2, in addition to the function of the electrode for a fluorescent lamp according to claim 1, alumina is contained between particles of barium tantalate or between barium tantalate and a multi-coil filament. By interposing between them, the adhesive force is increased, the adhesive force of barium tantalate to the multiple coil filament is improved, and the life can be further extended.

Further, in the invention described in claim 3, in addition to the effect of the invention described in claim 1 or 2, the electron emissive substance is several times as large as that in the case where the guide is only the multi-coil filament. Can be maintained and the lighting life can be improved.

In the invention according to claim 4, a mixture containing metal tantalum, barium peroxide and an organic binder is applied to the multi-coil filament, and then the multi-coil filament is electrically heated in vacuum. Then, an electron emissive material having a porous surface containing barium tantalate is formed, which facilitates the formation of a so-called hot spot, which is a cathode spot generated at the time of discharge. The damage of radioactive materials is mitigated.

Further, in the invention according to claim 5, after the fluorescent lamp electrode is manufactured by depositing an electron emissive material containing barium tantalate on the multi-coil filament, the fluorescent lamp electrode is fluorescent. Since it was mounted on both ends of the lamp bulb, the reaction of the mixture of barium peroxide and tantalum metal powder was not affected by the temperature rise during stem sealing, and during the heating reaction of barium peroxide and metal tantalum, The partially scattered mixture does not adhere to the inner wall of the valve in the vicinity of the electrode to turn black.

[Brief description of drawings]

1 shows a first embodiment of a fluorescent lamp electrode of the present invention and a fluorescent lamp provided with the electrode, wherein (a) is a front view of an electrode filled with an electron-emitting substance, and (b) is FIG. 3C is a front view of the electrode during the activation treatment, and FIG. 6C is a front view of the main part of the fluorescent lamp using the electrode.

2A and 2B show a first embodiment of a fluorescent lamp electrode of the present invention, in which FIG. 2A is a front view and FIG. 2B is a side view.

FIG. 3 is a partial sectional front view showing a conventional fluorescent lamp electrode.

[Explanation of symbols]

 1 Multi-coil filament 3 Electron emissive material 4 Mixture

Claims (5)

[Claims] 1. A fluorescent lamp electrode comprising a multi-coil filament coated with an electron emissive material, wherein the multi-coil filament is coated with an electron emissive material containing barium tantalate. electrode. 2. The electrode for a fluorescent lamp according to claim 1, wherein alumina is added to the electron emitting substance. 3. The electrode for a fluorescent lamp according to claim 1, wherein a guide for supporting the electron emitting substance is provided in the vicinity of the multi-coil filament. 4. The method of manufacturing an electrode for a fluorescent lamp according to claim 1, wherein the multi-coil filament comprises a mixture containing tantalum metal, barium peroxide, and an organic binder. After deposition, the multi-coil filament is electrically heated in a vacuum to form an electron emissive material containing barium tantalate on the surface of the multi-coil filament. . 5. A method of manufacturing a fluorescent lamp using the fluorescent lamp electrode according to claim 1, wherein the multi-coil filament comprises an electron emissive material containing barium tantalate. A method for manufacturing a fluorescent lamp, comprising depositing electrodes for a fluorescent lamp and then mounting the electrodes for the fluorescent lamp on both ends of the bulb of the fluorescent lamp.