JPH0745236A - Low pressure discharge lamp and lamp built in equipment - Google Patents

Abstract

PURPOSE:To provide a long life in small size with high efficiency further with simplification of manufacture by winding a filament coil to an external surface of a conductive sleeve. CONSTITUTION:In a small sized fluorescent lamp 11 which is a low pressure discharge lamp, a pair of right/left electrodes 13 are arranged to be opposed in a cylindrical bulb 12 made of quartz glass, and both end parts of the bulb 12 are sealed with glass-made beads 14. An internal surface of the bulb 12 is coated with a phosphor film 15, to seal rare gas and mercury in the bulb at a proper pressure. On the other hand, the electrode 13 is constituted such that a filament coil 17 of tungsten-made double coil or the like is wound to the external peripheral surface of a conductive sleeve 16 which is a cylindrical conductor opening the internal end made of nickel or the like, and also securing a lead bar 18 to an external end part internal surface of the sleeve 16. In an external end part of the bar 18, by extending it to the outside air-tightly inserted through the bead 14, the sleeve 16 is supported, and an enxtension end of the bar 18 is connected to a lighting circuit. Alkali earth metal carbonate or tungstic acid salt is applied as a thermoelectronic radiation substance to an external surface of the filament coil 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low pressure discharge lamp suitable for small fluorescent lamps and the like and a device incorporating the lamp, and
The present invention relates to a low-pressure discharge lamp which is mainly improved in a structure for supporting a filament coil contained in a bulb.

[0002]

2. Description of the Related Art Conventionally, as an example of a compact fluorescent lamp of this type, there is an actual utility model Shokai 19-19251, a practical utility model 3-26961.
There is one published in Japanese Patent No. The fluorescent lamp 1 has a pair of left and right electrodes 3 built in a glass bulb 2, and both axial ends of the bulb 2, or at least one end thereof, are hermetically sealed by glass beads 3. The bulb 2 has a phosphor film 5 on its inner surface.
Is deposited almost entirely, and a proper amount of rare gas and mercury are sealed in the bulb 2 at a proper pressure.

Each electrode 3 has a thin and flexible filament coil 3b built in a metal pipe 3a having openings at both ends, and a part of the filament coil 3b leans against the inner surface of the metal pipe 3a. By reducing the filament diameter of the filament coil 3b, power consumption is reduced, heat escape is reduced to facilitate spot formation, and lamp efficiency is improved.

[0004]

However, in such a conventional fluorescent lamp 1, even if the metal pipe 3a has a wall thickness of, for example, 0.01 mm, the lamp voltage gradually rises when the lamp is lit for about 1000 hours, Lighting with a constant lamp current causes a problem of increasing power consumption.

The main reason is the filament coil 3b.
The upper emitter evaporates and moves to and adheres to the inner wall of the metal pipe 3a, and the tip of the filament coil 3b is consumed quickly, but if the lamp current value is low, the temperature of the metal pipe 3a inevitably rises. This is because it is difficult and the diffusion of the emitter from behind the filament coil 3b is slow.

Further, since the low-rigidity and flexible filament coil 3b is leaning against and supported by the metal pipe 3a, the supporting strength of the filament coil 3b is very low and extremely weak against vibration and impact.

Further, as shown in FIG. 14, for example, a slightly crank-shaped plate 6 having a getter, a mercury dispenser or the like attached thereto is attached to the outer surface of the metal pipe 3c, so that the small plate 6 is made of a small metal. In addition to the need for a fine and complicated step of installing the pipe 3a, it is necessary to provide a space for installing the plate 6 in the valve 2 having a small diameter, which hinders the miniaturization of the valve 2.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a low-pressure discharge lamp and a lamp-embedded device which are compact and highly efficient, have a long life, and can be manufactured easily. To do.

[0009]

The present invention is configured as follows in order to solve the above-mentioned problems.

The invention according to claim 1 of the present application (hereinafter, referred to as the first
In the low pressure discharge lamp in which the electrode is built in the bulb, the electrode is formed by winding a filament coil around the outer surface of a conductor, and supporting the conductor by a lead rod.

In the invention according to claim 2 of the present application (hereinafter, referred to as the second invention), the conductor is a conductive sleeve, and at least one of the mercury dispenser and the getter is housed inside. It is characterized by

The invention according to claim 3 of the present application (hereinafter referred to as the third invention) is characterized in that the filament coil is coated with a thermionic emission material.

Furthermore, in the invention according to claim 4 of the present application (hereinafter referred to as the fourth invention), the thermionic emissive material is Ba.
₂ CaWO ₆ is a feature.

The invention according to claim 5 of the present application (hereinafter referred to as the fifth invention) is characterized in that the filament coil is a triple coil in which the filament coil wire is formed into a triple coil. And

Further, in the invention according to claim 6 of the present application (hereinafter, referred to as a sixth invention), a pair of electrodes are provided so as to face each other in the bulb, and at least one of the filament coils on the opposite side has one end. It is characterized in that the conductor is made to project further in the opposite direction than the opposite end of the conductor.

Furthermore, in the invention according to claim 7 of the present application (hereinafter referred to as the seventh invention), the filament coil is coated with the electron emitting substance only on the coil body other than the protruding end portion. Characterize.

The invention according to claim 8 of the present application (hereinafter referred to as the eighth invention) is any one of claims 1 to 7.
The low-pressure discharge lamp described in the item is incorporated as a light source.

[0018]

[Action]

<First to Eighth Inventions> Since the filament coil is supported by being wound around the outer surface of the conductor, the supporting strength of the filament coil can be improved. Therefore, the vibration resistance can be improved to prolong the life of the electrode, and thus the life of the lamp, and the conductor can be supported by the conductor with sufficient strength even if the diameter of the filament coil is reduced.

Therefore, by thinning the filament wire of the filament coil, it is possible to reduce power consumption, reduce heat escape and easily form spots, and improve lamp efficiency.

Furthermore, since the filament coil is wound around the outer surface of the conductor, the manufacture of the electrode can be simplified as compared with the conventional example in which the filament coil having low rigidity and flexibility is inserted into the conductor.

<Second Invention> Since at least one of the mercury dispenser and the getter is housed in the conductive sleeve, the valve can be made smaller and lighter than the conventional example in which the mercury dispenser and the getter are attached to the plate. it can.

Further, by inductively heating the conductive sleeve from the outside of the bulb, the mercury dispenser can easily discharge the mercury into the bulb.

<Third invention> Since the thermoelectron substance is applied to the filament coil wound around the outer surface of the conductive sleeve, the thermoelectron emitting substance can be firmly held by the conductive sleeve and the filament. Therefore, it is possible to reduce or prevent the thermionic emission material from falling off the filament coil.

<Fourth Invention> The thermoelectron emitting material is Ba ₂ C.
Since it is aWO _6, it is possible to omit the step of thermally decomposing the thermionic emission material in a vacuum atmosphere and the step of exhausting an impure gas generated during the thermal decomposition. Further, for this reason, since the electrodes can be assembled in the air, large equipment such as an exhaust chamber is not required, and the work in the exhaust chamber can be omitted. The workability of can be remarkably improved, and the manufacturing cost can be reduced.

<Fifth Invention> Since the filament coil is a triple coil, the mechanical strength can be increased correspondingly, and the thermionic emission material is applied to the triple coil. The holding power can be increased. In addition, the strength of attaching the filament coil to the conductive sleeve can be increased by increasing the diameter of the main wire of the triple coil, while the heat escape can be reduced by reducing the diameter of the sub wire that mainly carries the lamp current. Since it is possible to easily form spots, it is possible to improve the lamp efficiency.

<Sixth Invention> One end portion (front end portion) of the pair of filament coils opposed to each other inside the valve.
Are projected in the facing direction (inward) from the facing end (tip) of the conductive sleeve, so that the electric field is concentrated on the protruding end portion of this filament coil, and the electric field strength is increased. Therefore, the starting voltage can be reduced and the starting performance can be improved.

<Seventh Invention> The protruding end portion of the filament coil has a strong electric field strength, and the evaporation of the emitter due to sputtering is severe. Further, since the protruding end portion is exposed from the conductor, the protruding end portion is evaporated. The attached emitter may adhere to the inner surface of the bulb and blacken the bulb wall, shortening the lamp life.However, since the emitter is not coated on the protruding end of this filament coil, It is possible to increase the lamp life by reducing the blackening of the tube wall.

<Eighth Invention> As described above,
Since the low-pressure discharge lamp according to the seventh invention is small, highly efficient, has a long life, and is easy to manufacture, a lamp-embedded device incorporating these low-pressure discharge lamps is small, highly efficient, has a long life, and is easy to manufacture. it can.

[0029]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 12, the same or corresponding parts are designated by the same reference numerals.

FIG. 2 is a partially cutaway vertical sectional view of an embodiment of the present invention. In the figure, a small fluorescent lamp 11 which is a low pressure discharge lamp is shown in a cylindrical bulb 12 made of quartz glass, for example. A pair of middle left and right electrodes 13 and 13 are arranged so as to face each other, and both ends in the axial direction of the bulb 12 are hermetically sealed by, for example, a pair of left and right glass beads 14, 14 and a sealing member such as a glass stem. is doing.

The bulb 12 has a phosphor film 15 deposited almost entirely on the inner surface thereof, and a proper amount of rare gas and mercury are sealed in the bulb 12 at a proper pressure.

On the other hand, as shown in FIGS. 1 and 3, each electrode 13 has a filament such as a double coil made of tungsten on the outer peripheral surface of a conductive sleeve 16 which is a cylindrical conductor having an inner end opening made of nickel or the like. While the coil 17 is wound closely, the rod-shaped lead rod 18 is fixed to the inner surface of the outer end portion (right end portion in FIGS. 1 and 3) of the conductive sleeve 16, and the outer end portion of the lead rod 18 is formed. By extending each bead 14 in an airtight manner and extending outwardly, the conductive sleeve 16
And the extended end of the lead rod 18 is electrically connected to a lighting circuit (not shown).

As shown in FIG. 1, the conductive sleeve 16 has its inner surface axially divided into, for example, two regions, and one of them has a mercury dispenser 19 made of, for example, a Hg--Ti alloy.
On the other side, a getter 20 made of, for example, a Zr—Al alloy is attached.

The mercury dispenser 19 discharges an appropriate amount of mercury into the bulb 12 by heating the mercury dispenser 19, and the getter 20 occludes the impure gas remaining in the bulb 12 after the exhaust process in the bulb 12. In addition, only the mercury dispenser 19 is provided on the inner surface of the one conductive sleeve 16.
Only the getter 20 may be attached to the inner surface of the other conductive sleeve 16.

Therefore, according to this embodiment, since the filament coil 17 is supported by being wound around the outer surface of the conductive sleeve 16, the filament coil 17 can be firmly supported by the conductive sleeve 16 even if the wire diameter of the filament coil 17 is reduced. it can.

For that purpose, the filament coil 17
By reducing the diameter of the strand for use, it reduces power consumption, reduces heat escape and easily forms spots,
The lamp efficiency can be improved.

Further, since the filament coil 17 is supported by being wound around the outer surface of the conductive sleeve 16, it is possible to enhance vibration resistance against vibration and shock, and as a result, it is possible to prolong the service life of the electrode and thus the service life of the lamp.

Furthermore, since the filament coil 17 is wound around the outer surface of the conductive sleeve 16, the manufacturing of the electrode can be simplified as compared with the conventional example in which the flexible and flexible filament coil 17 is inserted into the conductive sleeve 16. You can

Further, since the filament coil 17 is wound around the outer surface of the conductive sleeve 16, the mercury dispenser 19 and the getter 20 can be accommodated in the conductive sleeve 16, respectively. Valve 1 as compared with one in which a plate 6 with a mercury dispenser is attached to the outer surface of a metal pipe 3a
It is possible to reduce the diameter by 2.

On the outer surface of the filament coil 17, an emitter (thermoelectron emitting substance) 21 (Ba, S
r, Ca) CO ₃ or BaCaWO ₆ is applied, and the former emitter 21 needs to be thermally decomposed and activated. Therefore, this (Ba, Sr, Ca) CO ₃ is used as the emitter 21 for the filament coil 17 An example of a method of manufacturing the fluorescent lamp 11 in the case of applying it on the substrate will be described with reference to FIGS. 4 to 6, a broken-line rectangular frame indicates the exhaust chamber 22.

First, as shown in FIG. 4 (A), (Ba, Sr, Ca) CO ₃ is applied to the outer surface of the filament coil 17 made of tungsten or the like in a predetermined exhaust chamber 22, and then, as shown in FIG. As shown in FIG. 4 (B), the filament coil 17 is electrically heated in a vacuum to obtain (Ba, Sr, Ca) O.
CO ₂ gas generated at that time is exhausted by the exhaust chamber 22.

Next, as shown in FIG.
The filament coil 17 is tightly fitted to the outer peripheral surface of the electrically conductive sleeve 16 to which is attached from the side thereof in the exhaust chamber 22 to assemble the electrode 13.

Thereafter, as shown in FIG. 6, a pair of electrodes 13 are inserted from the left and right sides into the bulb 12 already coated with the phosphor film 15 in an atmosphere such as argon gas in the exhaust chamber 22, Next, both ends of the opening of the bulb 12 are heated and sealed by the beads 14 or the like. After this sealing, valve 1
By inductively heating the conductive sleeve 16 from the outside of 2, the mercury dispenser 19 supplies an appropriate amount of mercury to the bulb 12.
It is released inside.

When high-frequency induction heating is performed during the exhaust process in the valve 12, as shown in FIG.
After sealing one end of 2, on the outer peripheral surface of the other opening end,
While the exhaust head 23 is air-tightly fitted and the inside of the valve 12 is exhausted by the exhaust head 23, the opening end of the valve 12 is heated and squeezed to seal the exhaust head 23. , 24b, the conductive sleeve 16 and the filament coil 17 are induction-heated to decompose the emitter 21 into (Ba, Sr, Ca) CO, and the CO ₂ gas generated at that time is exhausted by the exhaust head 23.

However, when the emitter 21 is BaCaWO ₆ , it is not necessary to thermally decompose and activate it, and therefore it is not necessary to heat the filament coil 17 in a vacuum and exhaust the CO ₂ gas. Therefore, while coating the filament coil 17 with BaCaWO ₆ in the atmosphere, the electrode 1
3 can be assembled in the atmosphere, the manufacture of the fluorescent lamp 11 can be simplified, and the relatively large exhaust chamber 22 shown in FIGS. 4 to 6 and the exhaust head 23 shown in FIG. Since it is unnecessary, cost can be reduced.

When the emitter 21 is thermally decomposed,
Since the mercury dispenser 19 and the getter 20 in the conductive sleeve 16 are heated at the same time, the mercury dispenser 19
There is a possibility that mercury will be emitted from the emitter and this emitted mercury will be absorbed by the getter 20.
In the case of WO ₆ , since thermal decomposition is not required, such inconvenience can be prevented and a high quality fluorescent lamp 11 can be provided.

The lighting test of the thus constructed fluorescent lamp 11 was carried out in the following manner together with the conventional fluorescent lamp 1 shown in FIG. 13, and the following results were obtained.

First, the outer diameter of the valve 12 is 4.1 mm, the inner diameter thereof is 3 mm, and the outer diameter of the nickel conductive sleeve 16 is 1.
0 mm, wall thickness is 0.05 mm, and the filament coil 17 is a double coil, and the wire diameter is about 30 μm and the distance between the pair of electrodes 13, 13 is 160 mm, the lamp current is 50 mmA at room temperature. When the conventional fluorescent lamp 1 shown in FIG.
Although it was 50 V, the lamp voltage gradually started to rise after 1000 hours of lighting.

On the other hand, in the fluorescent lamp 11 of this embodiment, the spot formed on the emitter 21 of the filament coil 17 during lighting is always searched for the best emission of thermoelectrons, and one end to the other end of the filament coil 17 is searched. Since it can be moved little by little toward
The lamp voltage could be maintained almost at the initial 250V even after 00 hours, and the spot moved only in the axial direction of the filament coil 17 to the intermediate portion.

The lamp voltage was 350 to 370 V when the cold cathode structure in which only the electrode 13 was made of a nickel plate in the same structure as this embodiment was used.

That is, according to this embodiment, for example, 500
Even if the lamp is lit for a long time of 0 hours or more, the lamp voltage can be kept low and stable.

FIG. 8 is a longitudinal sectional view of a main part of another embodiment of the present invention. The electrode 13a of this embodiment is characterized in that the filament coil 17 of the above embodiment is replaced with a triple coil 17a.

Next, an example of the structure and manufacturing method of the triple coil 17a will be described with reference to FIGS.

First, as shown in FIG. 9, for example, a tungsten-made 12.4 MG straight main wire 24 and a primary molybdenum wire 25 are bundled into a bundle, and a tungsten-made 1.0 MG sub-wire 26, for example, is closely packed on the outer periphery thereof. To form a primary coil 27. Here, MG indicates weight mg per 20 cm of the tungsten wire, and outer diameter (FD) indicates FD = 0.0182 (MG)
^Has a relationship of ^1/2 mm.

Next, as shown in FIG. 10, the primary coil 27 is further wound in a coil shape on the outer peripheral surface of the secondary molybdenum wire 28 to form a double coil-shaped secondary coil 29.

After that, as shown in FIG. 11, the secondary coil 29 is further wound around the outer peripheral surface of the piano wire 30 in a coil shape to form a triple coil-shaped tertiary coil 31.

Then, after removing the piano wire 30, the primary and secondary molybdenum wires 25 and 28 are melted to form a triple coil 17a of a triple coil.

Therefore, according to this embodiment, the filament coil 17 is replaced by the triple coil triple coil 17a.
The triple coil 17a enhances the holding force for holding the emitter 21, and the triple coil 17a enhances the holding force for holding the emitter 21. Coil 17
It is possible to reduce or prevent the emitter 21 from falling off from a.

Further, by increasing the diameter of the main wire 24, the attachment strength to the conductive sleeve 16 can be enhanced, so that the vibration resistance can be further enhanced and the life can be extended. On the other hand, since the sub wire 26 has a small resistance and is a wire that mainly conducts the lamp current when the electrode 13 is energized, by making the diameter of the sub wire 26 smaller,
The escape of heat can be reduced and the spot can be easily formed with a small current, and the lamp efficiency can be improved.

Further, by replacing the piano wire 30 at the time of forming the tertiary coil 31 with the conductive sleeve 16,
Since the step of removing the conductive sleeve 16 can be omitted, the manufacturing of the electrode 13 can be simplified and speeded up accordingly.

FIG. 12 is a front view of a main portion of still another embodiment of this embodiment. Each electrode 13b of this embodiment is a filament coil 17 on the opposite side facing the other electrode 13b in the bulb 12. It is characterized in that the tip portion 17b is slightly protruded, for example, 3 mm from the opposite end (tip) of the conductive sleeve 16.

Since the tip portion 17b of the filament coil 17 is projected forward, the projecting tip portion 17 is formed.
Since the electric field is concentrated on b and the electric field strength is improved, the following Table 1
As shown in, the starting voltage can be reduced to improve the starting performance.

This Table 1 shows the above-mentioned lighting test for the fluorescent lamp 11.
Also, the results obtained when the ambient temperature of the conventional fluorescent lamp 1 is 0 ° C. and 25 ° C. are shown.

[0064]

[Table 1]

In the filament coil 17, the emitter 21 may be applied to the portion other than the protruding end portion 17b, and the emitter 21 may not be applied to the protruding end portion 17b. According to this, the protruding end portion 17b of the filament coil 17 is
Since the electric field strength is strong and the sputtering is intense, when the emitter 21 is applied to the projecting end 17b, the emitter 21 easily evaporates and the projecting end 17b is exposed from the conductive sleeve 16. The emitter 21 evaporated from the projecting end 17b may adhere to the inner surface of the bulb 12 and cause blackening of the wall of the bulb, which may shorten the life of the bulb. Therefore, since the protruding end 17b is not coated with the emitter 21, it is possible to prevent the blackening of the bulb 12 and prolong the life of the lamp.

Further, although the case where the present invention is applied to the fluorescent lamp 11 has been described in the above embodiment, the present invention is not limited to this and can be applied to a low pressure discharge lamp in general. Further, the enclosed gas pressure and its gas composition are not limited to those in the above-described embodiment, and for example, Ar 50% -Ne 40% and the enclosed gas pressure may be 20-100 Torr, and Ar 5%-.
The filling gas pressure may be 20 to 100 Torr with Ne 95%.

Further, the shape of the valve 12 is not limited to a straight pipe, and may be a U-shape, a W-shape, or the like, and the valve shaft sectional shape is not limited to a circle, and may be an ellipse or a semicircle.

The outer diameter of the valve 12 is 4.1.
Not only mm, but when the diameter of the electrode 13 is increased or decreased, the outer diameter of the bulb 12 may be 8 mm to 2.5 mm. In this case, it goes without saying that the filled gas pressure, the filled gas composition, and the filament coil length are properly examined and determined in consideration of the lamp life and efficiency.

The fluorescent lamp 11 configured as described above is used as a backlight of a color or monochrome LCD (liquid crystal display device), a reading light source of OA equipment such as a copying machine, a display device such as a thin guide light or a signboard. It may be incorporated into a lamp-embedded device that incorporates a lamp such as a backlight, a hand lighting device, or another lighting device. According to these,
Since the fluorescent lamp 11 having the above effects is incorporated, it has the effects of being small and highly efficient, having a long life, and being easy to manufacture electrodes.

[0070]

As described above, according to the first to eighth inventions of the present application, since the filament coil is supported by being wound around the outer surface of the conductor, the supporting strength of the filament coil can be improved. Therefore, the vibration resistance can be improved to prolong the life of the electrode, and thus the life of the lamp, and the conductor can be supported by the conductor with sufficient strength even if the diameter of the filament coil is reduced.

Therefore, by thinning the filament wire of the filament coil, it is possible to reduce power consumption, reduce heat escape, and easily form spots to improve lamp efficiency.

Further, since the filament coil can be wound around the outer surface of the conductor, the manufacture of the electrode can be simplified as compared with the conventional example in which the flexible and low-rigidity filament coil is inserted into the conductor.

Further, according to the second invention of the present application, since at least one of the mercury dispenser and the getter is housed in the conductive sleeve, the valve can be made smaller and lighter than the conventional example in which the mercury dispenser and the getter are attached to the plate. be able to.

By inductively heating the conductive sleeve from the outside of the bulb, mercury can be easily discharged from the mercury dispenser into the bulb.

Further, in the third aspect of the invention, since the thermoelectron substance is applied to the filament coil wound around the outer surface of the conductive sleeve, the thermoelectron emitting substance can be firmly held by the conductive sleeve and the filament. Therefore, it is possible to reduce or prevent the thermionic emission material from falling off the filament coil.

Furthermore, in the fourth invention of the present application, since the thermionic emission material is Ba ₂ CaWO ₆ , the step of thermally decomposing the thermionic emission material in a vacuum atmosphere and the impurities generated during the thermal decomposition The step of exhausting the gas can be omitted. Further, for this reason, since the electrodes can be assembled in the air, large equipment such as an exhaust chamber is not required, and the work in the exhaust chamber can be omitted. The workability of can be remarkably improved, and the manufacturing cost can be reduced.

Further, in the fifth invention of the present application, since the filament coil is a triple coil, the mechanical strength can be increased correspondingly, and since the triple electron is coated with a thermoelectron emitting material, the heat It is possible to enhance the retention of the electron emitting substance. In addition, the strength of attaching the filament coil to the conductive sleeve can be increased by increasing the diameter of the main wire of the triple coil, while the heat escape can be reduced by reducing the diameter of the sub wire that mainly carries the lamp current. Since it is possible to easily form spots, it is possible to improve the lamp efficiency.

Further, according to the sixth aspect of the present invention, one end portion (tip portion) on the opposite side of the pair of filament coils arranged opposite to each other in the valve is arranged in the opposite direction (inward direction) from the opposite end (tip portion) of the conductive sleeve. Since the electric field is concentrated on the protruding end portion of the filament coil, the electric field strength is increased. Therefore, the starting voltage can be reduced and the starting performance can be improved.

Furthermore, in the seventh invention of the present application, the protruding end portion of the filament coil has a high electric field strength, the evaporation of the emitter due to sputtering is severe, and the protruding end portion is exposed from the conductor. The emitter that has evaporated from the protruding end may adhere to the inner surface of the bulb and cause blackening of the bulb wall of the bulb, shortening the lamp life, but the emitter is not applied to the protruding end of this filament coil. Therefore, the blackening of the tube wall can be reduced and the lamp life can be extended.

Further, in the eighth invention of the present application, as described above, the low-pressure discharge lamps according to the first to seventh inventions are small and highly efficient, have a long life and are easy to manufacture. The built-in lamp-equipped device is small, highly efficient, has a long life, and is easy to manufacture.

[Brief description of drawings]

FIG. 1 is an enlarged vertical sectional view of an electrode of the embodiment shown in FIG.

FIG. 2 is a partially cutaway vertical sectional view of an embodiment of a low-pressure discharge lamp according to the present invention.

FIG. 3 is an enlarged view of the electrode shown in FIG.

FIG. 4A is a diagram showing a process of applying an emitter to the filament coil shown in FIG. 2 and the like, and FIG. 4B is a diagram showing a process of thermal decomposition of the emitter by electric heating.

FIG. 5 is a diagram showing an assembling process of the electrode shown in FIG. 2 and the like.

FIG. 6 is a diagram showing a process of enclosing the pair of electrodes shown in FIG. 2 and the like in a valve.

FIG. 7 is a diagram showing a step of sealing the pair of electrodes shown in FIG. 2 and the like in a valve.

FIG. 8 is a longitudinal sectional view of a main part of another embodiment of the present invention.

9 is a partially cutaway perspective view showing a step of forming a primary coil of the triple coil shown in FIG.

FIG. 10 is a diagram showing a process of forming a secondary coil of the triple coil shown in FIG.

11 is a diagram showing a step of forming a tertiary coil of the triple coil shown in FIG.

FIG. 12 is an enlarged front view of the essential parts of yet another embodiment of the present invention.

FIG. 13 is a vertical cross-sectional view showing a part of a conventional example.

FIG. 14 is a partially enlarged perspective view showing another example of the conventional example shown in FIG.

[Explanation of symbols]

 11 Fluorescent Lamp 12 Bulbs 13, 13a, 13b Electrodes 14 Beads 15 Phosphor Film 16 Conductive Sleeve 17 Filament Coil 17a Triple Coil 18 Lead Rod 19 Mercury Dispenser 20 Getter 21 Emitter 22 Exhaust Chamber 23 Exhaust Head 24 Main Wire 26 Sub Wire 27 Primary Coil 29 secondary coil 31 tertiary coil

Claims (8)

[Claims] 1. A low-pressure discharge lamp having an electrode inside a bulb, wherein the electrode is formed by winding a filament coil around an outer surface of a conductor and supporting the conductor by a lead rod. . 2. The low-pressure discharge lamp according to claim 1, wherein the conductor comprises a conductive sleeve, and at least one of a mercury dispenser and a getter is housed inside the conductor. 3. The low-pressure discharge lamp according to claim 1, wherein the filament coil is formed by applying a thermionic emission material. 4. The low-pressure discharge lamp according to claim 3, wherein the thermionic emission material is Ba ₂ CaWO ₆ . 5. The low-pressure discharge lamp according to claim 1, wherein the filament coil is a triple coil formed by forming a filament coil element wire into a triple coil. 6. A pair of electrodes are provided so as to face each other in the bulb, and one end portion of at least one of the filament coils on the opposite side is made to project further in the opposite direction than the opposite end of the conductor. Any one of claims 1 to 5
Low-pressure discharge lamp according to the item. 7. The low-pressure discharge lamp according to claim 6, wherein the filament coil has an electron emitting substance applied only to the coil body other than the protruding end portion. 8. A lamp built-in device comprising the low-pressure discharge lamp according to claim 1 incorporated as a light source.