JP2000057993A - Electron discharging electrode structure, discharge lamp and discharge lamp device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the lifetime of an electrode from shortening and prevent the inner wall of a bulb from blackening while shortening the transferring time from the glow discharge to the arc discharge and while stabilizing the arc discharge by providing an electron emitting element formed of the granular bulk material for emitting the thermion and a discharge concentrating means for concentrating the discharge to an exposed surface while being arranged close to or contacting with at least one part of the exposed surface. SOLUTION: Arc discharge is generated from an exposed surface 55 of the most surface layer of an electron emitting element 5 housed in a container 6, in detail, from a surface of grains 51 in contact with the inner wall surface of an opening 62. Since the electron emitting element 5 made of the semiconductor porcelain (ceramics) has a large electrical resistance, current hardly flows, and arc spot is generated from grains 51... of the electron emitting element 5, which contacts with or arranged close to the inner wall of the container 6 as a conductor part. This arc spot is moved from the grain 51 to the adjacent grain 51 with the dispersion of the radioactive material, and discharge is thereby continued. As a discharge concentrating means, the container 6 works.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron-emitting electrode assembly having a long life, a discharge lamp in which the electrode assembly is sealed, and a discharge lamp device equipped with the lamp.

[0002]

2. Description of the Related Art Electron emission electrodes for discharge lamps are roughly classified into hot cathodes and cold cathodes. Of these, for example, a hot cathode in which a transition wire and an alkaline earth metal oxide containing barium are applied to a coil wound with a tungsten wire filament is often used.

As another hot cathode, there is known a hot cathode in which porous tungsten is impregnated with an electron-emitting substance containing, for example, barium tungstate.

On the other hand, in recent years, resource saving and energy saving have been promoted, and in addition to discharge lamps for general lighting such as fluorescent lamps, and discharge lamps for backlights mounted on OA equipment such as facsimile machines and video equipment such as liquid crystal televisions. In addition, demands for such devices have been increasing as well as higher efficiency and smaller (smaller) valves have been achieved.

However, among the above-mentioned hot cathodes, the former filament coil electrode cannot hold a large amount of electron-emitting substance because the filament coil length becomes shorter as the diameter of the bulb becomes smaller, and a satisfactory life cannot be obtained. At the same time, the vibration resistance was weak due to the thin wire. Further, the latter porous tungsten electrode is used in a high current type high pressure discharge lamp, but it is difficult to manufacture this electrode. Further, in a small current region of a low-pressure discharge lamp such as a fluorescent lamp, there is a problem that the cathode does not operate stably as a hot cathode.

As described above, in the above-mentioned hot cathode, a cold cathode made of a metal such as nickel or an aluminum-zirconium alloy is used because it is impossible to make the bulb of the discharge lamp narrower. The cathode drop loss was large, and a large lamp current could not be obtained.

Therefore, as a means for reducing the size of the discharge lamp and increasing the lamp current, for example, an electrode assembly described in Japanese Patent Application Laid-Open No. 1-65764 has been developed. Japanese Patent Application Laid-Open No. 1-65764 describes a hot cathode in which thermionic emission portions are formed by particles of semiconductor porcelain in a bottomed cylindrical container having an open front side.

According to the description of this publication, the thermal capacity of the thermionic radiating portion is made smaller than that of the container by making the thermionic radiating portion particulate, and the temperature of the thermionic radiating portion rises faster during glow discharge. The transition to arc discharge is facilitated by facilitating thermionic emission. In this case, since the current density can be increased, the outer diameter of the electrode can be reduced, and the bulb of the discharge lamp can be made narrower.

However, the semiconductor porcelain of the thermionic emission portion described in Japanese Patent Application Laid-Open No. 1-65764 does not reach a predetermined temperature during glow discharge due to insufficient activation of the surface. In some cases, no arc spot is formed in the thermionic emission portion, and the discharge may reach the periphery of the container. Then, when the discharge circulates into the container, the cathode drop voltage increases, so that the inner wall of the discharge lamp becomes black or the life of the electrode is shortened. In particular, when the thermionic emission capability of the thermionic emitting portion is reduced, the wraparound of the discharge is likely to occur before the end of the life of the electrode, which promotes shortening of the life.

Further, as described in, for example, JP-A-6-302297 or JP-A-9-507956, the hot cathode is held by a holder, and the holder is connected to a lead wire for supplying a current. Connected and led out of the discharge lamp.

In glow discharge, the holder serves as a cold cathode to serve as a supply source of electrons, and when the temperature rises in glow discharge, electron emission from the semiconductor porcelain is activated to shift to arc discharge.

However, Japanese Unexamined Patent Application Publication No.
In the configuration described in Japanese Patent Application Laid-Open No. 9-507957 or Japanese Patent Application Laid-Open No. 9-507956, the temperature of the thermionic emission portion hardly rises during glow discharge, and it takes time to shift to arc discharge. If the glow discharge time is long, the hot cathode is greatly affected by the ion sputtering, so that the hot cathode is disadvantageous. That is, an active substance on the surface of the semiconductor porcelain is sputtered, or a sputter of a container or an inner lead is deposited on the surface of the semiconductor porcelain, thereby increasing the work function, thereby causing a problem that the thermionic emission capability is reduced. In addition, the life of the electrodes is reduced, and the inner wall of the bulb of the discharge lamp is blackened.

[0013]

As described above, the semiconductor porcelain of the thermionic emission portion described in Japanese Patent Application Laid-Open No. 1-65764 has been disclosed in Japanese Patent Application Laid-Open No. 1-65764. If the temperature does not reach the predetermined temperature, an arc spot is not formed in the thermionic emission portion, and the discharge easily flows around the outer periphery of the container. And when the discharge wraps around the container,
When the cathode drop voltage is increased, the inner wall of the bulb of the discharge lamp is blackened, and the life of the electrode is shortened.

In the configuration described in JP-A-6-302297 or JP-T-9-507956, the temperature of the thermionic emission portion hardly rises during glow discharge, and it takes time to shift to arc discharge. If the glow discharge time is long, the hot cathode is greatly affected by the ion sputtering, so that the hot cathode is disadvantageous.

That is, the active material on the surface of the semiconductor porcelain is sputtered, and the sputtered material of the container or inner lead is deposited on the surface of the semiconductor porcelain. There is a problem that the electrode life is shortened and the inner wall of the bulb of the discharge lamp is blackened.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and can shorten the transition time from glow discharge to arc discharge, stabilize the arc discharge, and prevent a reduction in electrode life and blackening of the inner wall of the bulb. An object of the present invention is to provide an electron emission electrode assembly, a discharge lamp in which the electrode assembly is sealed, and a lamp device equipped with the discharge lamp.

[0017]

According to a first aspect of the present invention, there is provided an electron emitting electrode assembly comprising an aggregate of granules which are heated by electric discharge and emit thermoelectrons from an exposed surface; Discharge concentrating means for concentrating discharge on the exposed surface by approaching or contacting at least a part of the exposed surface of the body.

The electrode composed of the hot cathode performs a glow discharge as a cold cathode at the time of starting, and ions accelerated by a high cathode drop voltage heat the entire electrode to increase the temperature.
Since the particles of the electron emitter have a small heat capacity and a high thermal resistance with adjacent particles, the temperature is easy to rise, and after that, when the particles are heated intensively and reach a temperature at which thermoelectrons can be emitted sufficiently, the glow discharge starts. Transition to arc discharge.

That is, by providing the discharge concentrating portion, an electric field can be concentrated on the exposed surface of the electron emitter composed of aggregates of granules during glow discharge, and the temperature of the electron emitter can be increased in a short time.

According to a second aspect of the present invention, there is provided an electron emitting electrode assembly comprising an aggregate of granules which are heated by electric discharge and emit thermoelectrons from an exposed surface; It is characterized by comprising discharge concentrating means for concentrating discharge on the exposed surface by approaching or contacting at least a part thereof, and a container for accommodating the electron emitter.

When the container is made of a conductive material, the container itself is used as a conductor portion. When the container is made of an insulating or semi-insulating material, a separate member is provided near the electron emitter in the container. The electric field can be concentrated on the electric conductor during glow discharge by providing the electric conductor.

Then, an arc discharge occurs on the exposed surface of the surface of the electron emitter facing the opening of the container. An arc spot can be formed by raising the temperature of the electron emitter in a short time, promoting the transition from glow discharge to arc discharge, and when this electrode is used for a discharge lamp, the inner wall of the bulb is blackened. Or shorten the life.

According to a third aspect of the present invention, there is provided an electron-emitting electrode assembly comprising an electron-emitting body made of an aggregate of granules which are heated by electric discharge and emit thermoelectrons from an exposed surface; It is characterized in that the discharger is characterized in that a part of the emitter close to or in contact with at least a part of the exposed surface is used as a conductor and a container for concentrating discharge on the exposed surface.

By providing a conductive portion protruding toward the exposed surface of the electron emitter in the opening on the front side of the container, an electric field can be concentrated on the conductive portion at the time of discharge. It works.

According to a fourth aspect of the present invention, in the electron emission electrode assembly, the container is made of metal.

The material of the container, which is the main part of the electrode, is made of a metal having a relatively low vapor pressure even at the temperature reached by the electrode during discharge, such as W, Mo, Re, Ta, Ti, Zr,
It is made of at least one of Ni and Fe or an alloy of these metals, or a carbide C, a nitride N, a silicide Si or a boride B of these metals.

These substances function as good conductors at the time of energization, and can sufficiently flow to the electron-emitting body housed therein, thereby easily forming an arc spot and obtaining good electron emission.

In addition, Ba, Sr, Ca and T
It may be added with a semiconductor substance made of an oxide such as h. These containers have a smaller heat capacity than those made entirely of metal, and are less likely to release heat, so that arc spots are easily formed on the particles of the electron emitter.

An electron emission electrode assembly according to a fifth aspect of the present invention is characterized in that an outer surface of the metal container is coated with an insulating material.

The portion covered with the insulating coating is hardly discharged, and the electric field is concentrated on the portion where the metal is exposed, so that glow discharge can be generated intensively on a part of the exposed surface of the electron emitter.

This insulating coating can be formed using at least one kind of metal oxide such as aluminum oxide, silicon oxide, zirconium oxide and tantalum oxide, or a mixture thereof.

According to a sixth aspect of the present invention, in the electron emission electrode structure, the container is insulative or semi-insulating.

An electron emission electrode assembly according to a seventh aspect of the present invention is characterized in that the container is made of a metal oxide.

According to claims 6 and 7, the container is characterized in that an additive (Ta) is added to the mother crystal (BaTiO ₃ , BaZrO _3, etc.).
There is a semi-insulating material such as a semiconductor ceramic obtained by adding ₂ O ₃ or the like.

This container does not have a good conductivity at room temperature, but becomes a conductor when the temperature rises because the resistance value decreases. And once it becomes conductive, the container gets hot,
The activation of the electron emitter contained in the container is promoted to maintain the discharge.

In the case of a container having a high insulating property, the electron emitter is electrically connected to the electron emitter contained in the container.
The surface of the container may be provided with a coating made of a conductive metal plate, a metal carbide, a metal nitride, or the like.

In the electron-emitting electrode assembly according to the present invention, the container is formed of a material mainly composed of at least one oxide of an alkaline earth metal, a transition metal and a rare earth metal. Is characterized in that a coating of at least one of an alkaline earth metal, a transition metal and a rare earth metal is formed of a carbide and / or a nitride.

At least a part of the container is mainly made of at least one oxide of an alkaline earth metal, a transition metal and a rare earth metal, and the surface of the container is made of TaC or TiC.
By forming a coating of a high melting point material made of a carbide such as TiN or a nitride such as TiN or ZrN, it is possible to reduce scattering and evaporation of the container by ion sputtering as described in claims 17 and 18 described later. can do.

As a material for forming the container, for example, BaO,
SrO, CaO, Ba ₄ Ti ₂ O ₉ , BaTaO ₃ , S
Those mainly composed of alkaline earth metals such as rTiO ₃ and SrZrO ₃ + metal oxides and those mainly composed of alkaline earth metals such as BaCeO ₃ and rare earth (Sc, Y, La and lanthanoid) metal oxides Can be used. An electron emission electrode assembly according to a ninth aspect of the present invention is characterized in that the container is supported by a holder.

When the container is made of an insulating or semi-insulating material, it acts as a conductor, and makes electrical and mechanical connections such that the container can be securely held. .

According to a tenth aspect of the present invention, in the electron emission electrode assembly, the discharge concentrating means is a metal projection which is close to or in contact with at least a part of the exposed surface of the electron emitter.

The electric field is more concentrated during glow discharge by making the tips of the metal projections having a rod shape or a plate shape sharp. The sharp part of this tip is needle-like, angular,
Any shape including a conical shape, a pyramid shape, a truncated cone shape, a truncated pyramid shape, an arc shape, and the like may be used as long as the electric field concentration occurs.

When the container is conductive and a conductor portion is provided separately from the container, it is preferable that both are electrically connected to have the same potential. Further, the conductor portion may be integrated with the container or the holder, or may be provided with another member integrally.

An eleventh aspect of the present invention is characterized in that the metal projection has a tongue shape.

According to a twelfth aspect of the present invention, in the electron emission electrode assembly, the discharge concentrating means is a rod-like projection penetrating the electron emitter and projecting from the exposed surface. By projecting rod-shaped projections such as electrode rods from the electron-emitting body in the container, the electric field can be concentrated on the projections projected during discharge. Then, by increasing the temperature of the electron emitter in contact with or in proximity to the projection, an arc spot can be formed.

According to a thirteenth aspect of the present invention, in the electron emission electrode assembly, the rod-shaped projection is projected from a center of the exposed surface.

According to a fourteenth aspect of the present invention, in the electron emission electrode structure, the rod-shaped projection projects eccentrically from the center of the exposed surface.

The protruding rod-shaped protrusions protrude from a position deviated from the center of the exposed surface of the electron-emitting body.
The temperature of the electron emitter that is in contact with or in the vicinity of the protruding portion and the inner wall of the container where an arc spot is likely to be formed is easily increased, and the transition from the glow discharge to the arc discharge can be improved.

According to a fifteenth aspect of the present invention, in the electron emission electrode assembly, the discharge concentrating means is a metal mesh that covers an opening of the container.

By providing a conductor portion made of a metal mesh facing the exposed surface of the electron emitter in the opening on the front side of the container, the electric field concentrates on the mesh during glow discharge, so that the temperature of the electron emitter is increased. An arc spot can be easily formed, and the transition to arc discharge is promoted during glow discharge. When this electrode is used in a discharge lamp, the inner wall of the bulb is not blackened and the life is not shortened.

The mesh may be formed by knitting a metal wire such as Ni, W or stainless steel, or a mesh formed by perforating a metal plate with a large number of holes.

The electron emission electrode assembly according to a sixteenth aspect of the present invention is characterized in that the discharge concentrating means is formed on the container or the holder.

According to a seventeenth aspect of the present invention, there is provided the electron-emitting electrode structure, wherein the granules of the electron-emitting body are formed mainly of at least one oxide of an alkaline earth metal, a transition metal and a rare earth metal. It is characterized by having been done.

As a forming material, for example, BaO, Sr
O, CaO, Ba ₄ Ti ₂ O ₉ , BaTaO ₃ , SrT
Alkaline earth metal such as iO ₃ , SrZrO ₃ + metal oxide or alkaline earth metal such as BaCeO ₃ + rare earth (Sc, Y, La, lanthanoid, etc.)
A material mainly composed of a metal oxide can be used.
These have a low work function, have a small cathode drop loss, and have an effect that they do not react with atmospheric components to facilitate manufacture.

According to the electron emission electrode structure of the present invention, at least one of an alkali earth metal, a transition metal and a rare earth metal is formed of a carbide and / or a nitride on the surface of the particle of the electron emitter. Characterized by the fact that a film of

At least a part of the surface of the granules of the electron-emitting body is formed of at least one of a carbide and / or a nitride of an alkaline earth metal, a transition metal and a rare earth metal, as a coating of Ti, Ta, Zr, Nb, A thin film of a high melting point material made of a carbide or nitride such as Hf or W, for example, a carbide such as TaC or TiC, or a nitride such as TiN or ZrN is formed. Thereby, it is possible to reduce scattering and evaporation of the electrode material, particularly the alkaline earth metal that contributes to the emission (electron emission) by the ion sputtering.

The discharge lamp according to claim 19 of the present invention is
A glass bulb for enclosing a gas to be discharged, an electron emitter made of an aggregate of granules provided in the bulb, and heated by the discharge of the gas to emit thermoelectrons from an exposed surface; and An electron emission electrode structure comprising discharge concentrating means for concentrating discharge on the exposed surface by approaching or contacting at least a part of the exposed surface.

According to a twentieth aspect of the present invention, there is provided a discharge lamp device, wherein a glass bulb for forming a discharge path by enclosing a gas to be discharged is provided at an end of the glass bulb, and is heated and exposed by the discharge of the gas. An electron emitter made of an aggregate of granules that emit thermoelectrons from a surface, and discharge concentrating means for concentrating a discharge on the exposed surface by approaching or contacting at least a part of the exposed surface of the electron emitter. An electron emission electrode assembly, and a power supply circuit device connected to the electron emission electrode assembly and applying a voltage between the electrode assemblies.

According to a twenty-first aspect of the present invention, there is provided a discharge lamp device comprising an aggregate of granules provided in a glass bulb for enclosing a gas to be discharged and heated by the discharge of the gas to emit thermoelectrons from an exposed surface. A discharge lamp comprising: an electron-emitting body; and an electron-emitting electrode assembly comprising: a discharge concentrating unit that approaches or contacts at least a part of the exposed surface of the electron-emitting body to concentrate a discharge on the exposed surface; A housing for accommodating the discharge lamp.

An illumination device using this discharge lamp device is:
It can be widely used as OA equipment for backlighting of liquid crystal display devices, liquid crystal televisions and decorative devices, reading documents such as facsimile machines, exposing and removing static electricity of copiers, and ordinary lighting equipment and lamps.

[0061]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electron-emitting electrode structure and a discharge lamp according to the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway plan view showing a discharge lamp device, and FIG. 2 is a longitudinal sectional view showing an electron emission electrode assembly.

Referring to FIG. 1, reference numeral 1 denotes a discharge lamp, for example, a fluorescent lamp.
~ 15mm, here about 4mm, total length about 300m
The hot cathodes 3A, 3A as electrode structures are disposed opposite to each other inside the glass bulb 2 which is a light-transmitting container having a length of m and lead wires 4, 4 connected to the hot cathodes 3A, 3A at the ends. Are hermetically sealed.

A rare gas such as an argon gas (Ar) serving as a discharge medium is contained in the glass bulb 2 for 20 tons.
rr and mercury are enclosed. The hot cathodes 3A, 3A
The distance between them is set to about 260 mm. further,
A phosphor coating (not shown) is formed on the inner or outer wall surface of the glass bulb 2 by coating.

The hot cathode 3A is composed of a container 6 filled with electron emitters 5, a holder 7A for holding the container 6, and a lead wire 4 for supporting and electrically connecting the holder 7A. It is configured. (The hot cathode may not include a lead wire in some cases.) The container 6 is made of a conductive material such as tantalum Ta and zirconium Zr as a main component, and has a circular bottom surface 61 and an opening at the tip. Circular concave portion 6 having a bottomed cylindrical (cup) shape having a portion 62 and having an outer peripheral side surface.
3 are formed.

The holder 7A is made of nickel and has a bottomed cylinder (cup) shape having a circular bottom surface 71 for receiving the container 6 and an opening 72.
3, the periphery of the opening 72 of the holder 7A is inserted and caulked to be integrated, and both are mechanically and electrically connected, and the container 6 is coaxially attached to the holder 7A. ing.

The container 6 has a diameter of 10 μm.
To 500 μm, preferably 20 μm to 10 in diameter
An electron emitter 5 composed of a plurality of aggregates of semiconductor porcelain granules 51 mainly composed of 0 μm particulate barium Ba and tantalum Ta oxides to which a small amount of zirconium oxide ZrO ₂ is added is filled and housed. ing. Reference numeral 8 denotes an insulator made of aluminum oxide, which is coated on the lower surface side of the recess 63 on the outer surface of the container 6 and on the inner surface of the holder 7A.

The lead wire 4 is welded to substantially the center of the bottom surface 71 of the holder 7A.
The holder 7A, the electron emitter 5, and the lead wire 4 constitute a hot cathode 3A.

The conductive material forming the container 6 is, in addition to the above, tungsten T, molybdenum Mo, rhenium Re, titanium Ti, tantalum Ta, zirconium Z.
r, niobium Nb, hafnium Hf, nickel Ni or iron F
e or an alloy of these metals or carbides C, nitrides N, silicides Si of these metals
Or boride B or the like. Further, a semiconductor material including an oxide such as barium Ba, strontium Sr, calcium Ca, or thorium Th may be added to the above metals.

As another material for forming the container 6, for example, a semi-insulating material such as a semi-insulating material obtained by adding an additive (such as Ta ₂ O ₃ ) to a mother crystal (such as BaTiO ₃ or BaZrO ₃ ) is used. Ceramics or BaO, SrO, CaO, Ba ₄ Ti ₂ O ₉ , BaT
Alkaline earth metal such as aO ₃ , SrTiO ₃ , SrZrO ₃ + metal oxide or alkaline earth metal such as BaCeO ₃ + rare earth (Sc, Y, La, lanthanoid, etc.) metal oxide Can be used.

Further, in the case of the container 6 made of the above-mentioned alkaline earth metal, transition metal and rare earth metal material, at least one of the alkaline earth metal, transition metal and rare earth metal carbide or Nitrides,
For example, by forming a coating of a high melting point material made of a carbide such as TaC or TiC or a nitride such as TiN or ZrN, it is possible to reduce scattering and evaporation of the electrode container 6 due to ion sputtering.

When the container 6 is insulative, a conductive metal plate or rod may be brought close to the surface of the container 6 or a coating made of metal carbide or metal nitride may be formed. .

The electron emitter 5 is made of barium Ba, strontium Sr, calcium C
a oxide, Ba ₄ Ti ₂ O ₉ , BaTaO ₃ , SrT
Alkaline earth metal such as iO ₃ , SrZrO ₃ + metal oxide or alkaline earth metal such as BaCeO ₃ + rare earth (scandium Sc, yttrium Y, lanthanum La, lanthanoid, etc.) metal oxide Can be used.

In the case of the electron emitter 5 made of the above-mentioned alkaline earth metal, transition metal and rare earth metal material, the surface of the above-mentioned alkaline earth metal,
By forming a film of at least one of a transition metal and a rare earth metal, such as a carbide or nitride, for example, a carbide such as TaC or TiC, or a nitride such as TiN or ZrN, a high melting point material is formed. Can be reduced from being scattered or evaporated by ion sputtering.

In manufacturing the container 6 and the electron emitter 5, both may be sintered together.

The holder 7A can also be formed of a material containing at least one of conductive metals such as nickel Ni, tantalum Ta, titanium Ti, zirconium Zr, aluminum Al and tungsten W.

The holder 7A is not limited to a cover structure for covering and holding substantially the entire outer surface and the bottom surface 61 of the container 6, but may be a column structure such as a frame. Furthermore, when the lead wire 4 can be directly connected to the container 6 to support and electrically connect the container 6, the holder 7A is not particularly required.

The formation of the insulator 8 is 0.1 μm
A solution in which the following aluminum oxide fine particles are dispersed in an alcohol-based solvent is applied using a brush, and after the application, approximately 200
The coating may be formed by removing the solvent and moisture by heating in an atmosphere at a temperature of about 5 ° C. for about 5 minutes, or by dipping a necessary part in the solution or by adding the solution. The insulator 9 is made of aluminum oxide Ai ₂ O ₃ ,
At least one of metal oxides such as silicon oxide SiO ₂ , zirconium oxide ZrO ₂ and tantalum oxide Ta ₂ O ₅
It may be formed using a seed or a mixture.

Then, the hot cathodes 3A, 3A having the above structure as the electrode assembly are sealed in the glass bulb 2 to complete the fluorescent lamp 1, and then the lead wires 4, 4 (or the base if the base is provided) are turned on at high frequency. When connected to a power supply circuit device C having a circuit or the like, a current flows through each holder 7A made of a conductor to the container 6 made of the same conductor that is electrically connected to the support 7A. .

Then, a discharge is generated between the hot cathodes 3A and 3A by using the container 6 disposed opposite to both ends of the glass bulb 2 serving as a discharge path as a conductor portion, and this discharge causes the bulb 2 to discharge.
The rare gas is ionized and excited to generate ultraviolet rays, and the ultraviolet rays are converted into visible light by the phosphor coating, and the visible light is transmitted to the outside through the bulb 2 wall.

The hot cathode 3A, which is disposed facing this discharge path,
The discharge from 3A is a glow discharge as a cold cathode at the time of startup, and ions accelerated by a high cathode drop voltage heat the entire electrode to increase the temperature.
1,... Have a small heat capacity and a high thermal resistance with the adjacent granules 51, so that the temperature is easily raised. After that, when the granules 51 are heated intensively and reach a temperature at which thermoelectrons can be sufficiently emitted, the glow discharge starts. The transition to the arc discharge occurs, and an arc spot is formed on the granules 51 to operate as a hot cathode. And
The glow discharge occurs from almost the entire surface of the conductive container 6 except for the outer surface thereof, and then proceeds to arc discharge. This arc discharge is caused by the exposed surface 55 of the outermost surface of the electron emitter 5 filled and stored in the container 6. More specifically, it originates from the surface of the granule 51 in contact with the inner wall surface of the opening 62. This is because the electron emitter 5 is a semiconductor porcelain (ceramic) and has a large electric resistance, so that current does not easily flow, and the electron emitter 5 is in contact with or close to the inner wall of the container 6 which is a conductor portion.
An arc spot is generated from the granules 51,. When the electron-emitting substance is scattered and consumed from the granules 51 forming the electron emitter 5, the arc spot moves to the adjacent granules 51 and discharge is continued.

Further, a gap is formed between the outer surface of the container 6 coaxially polymerized and the inner surface of the holder 7A, and this gap acts as a hollow cathode to allow discharge to flow around this portion. And However, in the present invention, the insulator 8 formed on the outer surface of the container 6 and the inner surface of the holder 7A prevents the discharge from sneaking into the bottom side of the container 6, so that the discharge is stabilized.

As a result, as a means for concentrating the discharge of the hot cathode 3A, the container 6 having conductivity performs its function, the temperature of the electron emitter 5 appropriately rises, and the arc spot moves greatly during lighting. The arc spot is appropriately formed without any fluctuations in the discharge without any discharge, and a stable discharge can be maintained.

In the fluorescent lamp 1, the transition time from the glow discharge to the arc discharge is short, the cathode drop voltage can be reduced, the luminous efficiency can be improved, and the spatter due to ion bombardment can be reduced. And the life can be extended.

FIGS. 3 and 4 show the measurement of the cathode drop voltage (V) when the outer surface of the container 6 and the inner surface of the holder 7A are coated with the insulator 8 and when the insulator 8 is not formed. The results are shown.

Compared with the case where the insulator 8 shown in FIG. 4 is not formed, when the insulator 8 shown in FIG. 3 is formed, the cathode current drop (V) with respect to the discharge current (A) is obtained. ) Does not fluctuate almost stably, and the same discharge current (A)
, The cathode drop voltage (V) with respect to the current value can be reduced, and the electrode life can be prevented from being shortened.

Next, another embodiment of the hot cathode as the electrode assembly of the present invention will be described with reference to FIG. FIG. 5 is a perspective view showing the hot cathode 3B, which is the same as that shown in FIG. 1 except for the holder, and the same portions are denoted by the same reference numerals and description thereof will be omitted.

The holder 7B shown in FIG. 5 has a bottomed cylindrical shape similar to that of the above-described embodiment, and a pair of projections 73, 73 protruding from the end face of the opening 72 of the holder 7B are erected. Is formed. The projections 73 have a claw-shaped tongue piece 74 bent inward at a substantially right angle inward of the electron emitter 5 above the opening 62 of the container 6. The tips of the tongue pieces 74, 74 are formed in an acute triangular shape, and the sharp tips 75, 75 of the two tongues are arranged facing the exposed surface 55 of the surface layer of the electron emitter 5 so as to be spaced apart from each other. .

Therefore, by bending the tip end portion 75 of the tongue piece 74 at the corner of the container 6, the container 6 can be easily mounted and held on the holder 7B without damaging the container 6. Can be prevented from moving in the axial direction.
Further, even if thermal expansion occurs in the holder 7B, such as during discharge, the container 6
, The container 6 can be prevented from falling off.

The projection 73 is integrally formed from the holder 7B.
Although the projection 73 is formed, the projections 73 may be formed separately from the holder 7B and then integrated later as long as they are electrically connected to the holder 7B. Not only two but also one or three or more may be formed.

The hot cathode 3B is connected to the tongue piece 74 of the projection 73 serving as the discharge concentrating conductor part by the opening 62 of the container 6.
The glow discharge is generated at the tip end portion 75 by being mounted on the electron emitter 5 facing upward. And glow discharge is
An electric field is concentrated at the tip portion 75, and the temperature of the granules 51,... Of the electron emitter 5 located in the vicinity thereof is promoted, and an arc spot can be easily formed on the surface of the granules 51 of the electron emitter 5. In this way, the transition from glow discharge to arc discharge in a short time, ion sputtering hardly occurs,
Blackening of the inner wall of the glass bulb 2 and reduction of the electrode life can be prevented. Note that the tip portion 75 of the tongue piece 74 is preferably sharp when the tip portion is sharp because an electric field concentration tends to occur.

FIG. 6 shows a discharge lamp of the present invention (characteristics are indicated by ●) using an electrode 3B having a conductor portion formed of a tongue piece 74 of the embodiment shown in FIG. Discharge lamp without conductor part (characteristics are indicated by crosses)
Input power [W] and glow arc time [τg
(Second- ¹ )] is a graph comparing with the reciprocal of (Second- ¹ )].

As shown in FIG. 6, in the case where the projection 73 (conductor portion) is formed, the reciprocal of the glow arc transition time τg can be increased with a small input power W.
Therefore, by forming the projections 73 (conductor portions) 74, the glow arc transition time can be shortened, and the time during which ion sputtering or the like occurs can also be shortened.

Next, another embodiment of the hot cathode which is the electrode structure of the present invention will be described with reference to FIGS.
7 and 8 show the same hot cathode 3C, FIG. 7 is a plan view, FIG. 8 is a side view of FIG. 7, and FIGS. 9 and 10 show the same hot cathode 3D, FIG. 9 is a side view of FIG. 9. Both hot cathodes 3C and 3D have the same configuration as that shown in FIG. 1 or FIG. 5 except for a holder, and the same portions are denoted by the same reference numerals and the description thereof will be omitted. Omitted.

The hot cathode 3C shown in FIGS. 7 and 8 also has the container 6 housed in the holder 7C. The holder 7C has a bottomed cylindrical shape similar to that of the hot cathode 3B shown in FIG.
A pair of protruding portions 73, 73 protruding upward from the end face of the opening 72 are integrally formed upright. This projection 7
Reference numerals 3 and 73 denote openings 62 of the container 6 as discharge concentration conductors.
A tongue piece 74 which is a conductor portion bent slightly inward at a position slightly above and facing the exposed surface 55 of the surface layer of the electron emitter 5 toward the inside is provided. And this tongue piece 74,
The arc-shaped tip portions 76, 74 face the exposed surface 55 of the surface layer of the electron emitter 5, and are arranged facing away from each other.

As shown in FIGS. 7 and 8, even if the tip portions 76, 76 of the projections 73, 73 are formed in an arc shape,
Electric field concentration can occur between the tips 76,76.

Here, in the embodiment shown in FIGS. 7 and 8, a hot cathode 3C shown in the embodiment having a projection 73 forming a conductor having a tip portion 76 formed in an arc shape, A starting lighting voltage test and a blinking test were performed for comparison using a hot cathode having no projection 73.

In the test, the diameter of the glass bulb 2 was about 6 m.
m, the distance between the hot cathodes 3C, 3C was about 150 mm, and the fluorescent lamp 1 in which argon gas was sealed at about 100 Torr was used, and the projection 73 was formed using a nickel metal plate having a width of about 1 mm.

In the starting lighting voltage test, when the voltage at which the glow discharge shifts to the arc discharge is defined as the starting lighting voltage, the protrusion 73 is set as shown in Table 1. It can be seen that the formed one greatly reduces the starting voltage.

[0100]

[Table 1] In the blinking test, the secondary open circuit voltage was about 2.3 kVrm.
s, lamp current about 20 mA, lamp voltage about 200 Vrm
s for 30 seconds using a lighting circuit having the characteristics of
When the number of times until turning off was measured by repeating the blinking and turning on and off as one cycle for one second, the number of times until turning off was large in the case where the projections (conductor portions) 73 were formed as shown in Table 2. It can be seen that the blinking life increases.

[0101]

[Table 2] Next, another embodiment of the hot cathode 3D which is the electrode structure of the present invention shown in FIGS. 9 and 10 will be described.

In the hot cathode 3C shown in FIGS. 7 and 8, a projection 73 having a tongue piece 74 is formed integrally with the holder 7C. The hot cathode 3D is provided separately from the holder 7D. Are connected to a projection 77 formed of a rod-shaped body that forms a conductor portion bent at a right angle. The tip of the rod-shaped projection 77 faces the exposed surface 55 of the surface layer of the electron emitter 5 in the container 6. .

As described above, the discharge concentrating means can be
Thus, the same operation and effect as those of the projection 73 shown in FIGS. 7 and 8 can be obtained. The rod-like projection 77
If the tip is sharpened, the electric field is concentrated and the effect can be further improved.

Another embodiment of the hot cathode as the electrode structure of the present invention will be described with reference to FIGS. 11 and 12 show the same hot cathode 3E, and FIG.
1 is a plan view, FIG. 12 is a side view of FIG. 11, and the same parts as those shown in FIG. 1 to FIG.

The hot cathode 3E shown in FIGS.
The plate-like tongue piece 73 and the rod-like projection 77 described above
Instead, a mesh-like metal mesh 78 knitted vertically and horizontally with a conductive metal wire or formed with a large number of through-holes in a metal plate is placed in the opening 62 on the front surface of the container 6 in the electron emitter 5.
It is provided so as to cover and close the exposed surface 55 of the surface layer.

As described above, even when the discharge concentration means is a metal mesh 78 having conductivity, the same operation and effect as those of the hot cathode of the above embodiment can be obtained.

This mesh 78 is made of nickel Ni,
A braided metal wire such as tungsten w or stainless steel, or a perforated metal plate having many holes can be used.

Further, another embodiment of the hot cathode as the electrode structure of the present invention will be described with reference to FIGS. 13, 14, and 16 show hot cathodes 3F, 3G,
FIG. 15 is a perspective view showing 3H, and FIG. 15 is a plan view of a cross section of a part of the fluorescent lamp 1 in which the hot cathode 3G of FIG. 14 is sealed, and the same parts as those shown in FIGS. The description is omitted. This FIG. 13, FIG. 14 and FIG.
Each of the hot cathodes 3F, 3G, and 3H uses a rod-like projection made of an electrode rod as a discharge concentrating means.

A hot cathode 3F as an electrode assembly shown in FIG.
The container 6F has a through hole (not shown) in the center of the bottom surface 61.
Are formed, and tungsten W, molybdenum Mo, and titanium Ti penetrate between the through-holes and the granules 51 of the particulate electron-emitting body 5 filled and housed in the container 6F, and project from almost the center of the opening 62. , Tantalum Ta or nickel Ni
An electrode rod 4A serving as a conductor portion made of, for example, is provided. The electrode rod 4 </ b> A forming the rod-shaped protrusion may be one that also serves as the tip of the lead wire 4, or may be one that is formed separately from the lead wire 4 by welding or the like.

For example, the lead wire 4 serving also as the electrode rod 4A is fixed by welding to a through hole of the container 6F. Further, when the tip of the electrode rod 4A protruding from the opening 62 and forming the conductor portion is formed at an acute angle, discharge is more likely to occur.

As described above, the container 6F and the electron emitter 5
By projecting the tip of the electrode rod 4A, which also serves as the conductive lead wire 4 penetrating therethrough, into the opening 62, the electric field can be concentrated at the tip. By increasing the temperature, the granules 51,... Of the electron emitters 5 that are in contact with or in proximity to the electrode rod 4A can be activated. Then, the granules 51 in contact with the outer surface of the electrode rod 4A
An arc spot is generated from the surface of the granules, and when the electron emission from the granules 51 is completed, the arc spot moves to the adjacent granules 51. The arc spot moves to the adjacent granules 51 one after another, and the discharge is stably continued. It has a function that can be performed.

The hot cathode 3G shown in FIG. 14 is different from the hot cathode 3F shown in FIG. 13 in that the lead wire 4 serving also as the electrode rod 4A composed of a bar-shaped projection is coaxial with the container 6G axis but from the center axis 69. It penetrates the offset position.

That is, the lead wire 4 also serving as the electrode rod 4A
Is located on the central axis of the container 6F on the base end side outside the container 6G, but a bent portion 41 is formed near the outside of the bottom surface 61 of the container 6G to form a conductor portion protruding from the inside of the container 6F and from the opening 62. In the part, it is configured to be arranged offset from the center axis 69 of the container 6F.

Then, the hot cathodes 3G, 3G are
The fluorescent lamp 1A is completed by sealing to the end of the glass bulb 2 as shown in FIG. In the hot cathode 3G, a current flows through the conductive electrode rod 4A and the container 6G at the time of energization, and a discharge occurs between the hot cathode 3G and the opposing hot cathode 3G. At this time,
The electrode rod 4A in the container 6G is connected to the central axis 6 of the container 6G.
9, because it is closer to the inner wall of the container 6G than when it is on
The electrode rod 4A and the container 6G which constitute the conductor portion are hot cathode 3G.
As the temperature rises, the temperature of the electron-emitting body 5 also rises, and the activation of the particles 51,.

Even when the electrode rod 4A is located at an offset position not located at the center of the container 6G, the arc spot is generated by the particles 51 of the electron emitter 5 facing the opening 62,
.., An appropriate arc discharge can be performed, and a slight deviation has little effect on the light emission characteristics. Also, this lamp 1A
Since the lead wire 4 is sealed substantially on the central axis of the bulb 2 at the sealing portion at the end of the bulb 2, cracks caused by unevenness of the glass wall due to bias of the lead wire 4 and the like are caused. There is no occurrence.

When the granules 51 of the particle-shaped electron emitter 5 near the inner wall of the container 6F run out of the electron emitting material and no longer emit thermionic electrons, the other granules 51 adjacent in the circumferential direction of the inner wall of the container 6 are removed. It was confirmed that the electron emission function was transferred to the granules 51 adjacent in the inner wall circumferential direction sequentially after the emission of thermionic electrons.

When the relationship between the average input power W and the reciprocal of the glow arc transition time τg of the fluorescent lamp 1A using the hot cathodes 3G, 3G is almost the same as that shown in FIG. Conductive rod 4A protruding from container 6G
Can increase the reciprocal of the glow arc transition time τg with a small input power. Therefore, by forming the protruding conductive rod 4A, the glow arc transition time can be shortened, and the time during which ion sputtering or the like occurs can be shortened.

A hot cathode 3H according to another embodiment will be described with reference to FIG. FIG. 16 is a perspective view showing a hot cathode. A hot cathode 3H as an electrode shown in FIG. 16 has an electrode rod 4A serving also as a lead wire 4 erected along a central axis of a container 6H, and is connected to the lead wire 4. A branch part 42 is formed, and a plurality of, for example, four electrode rods 4B are provided in a branch shape from the branch part 42 almost in parallel with the electrode rod 4A, and each of the tip parts protrudes from the opening part 62 as a rod-shaped projection. .

The electrode rods 4A, 4B,... Made of rod-shaped projections constituting the conductors may be arranged at equal intervals around the electrode rod 4A, or at irregular intervals. They may be arranged, and the number of branches may be one or more.

By providing a plurality of electrode rods 4A, 4B,...
The temperature rise not only in the vicinity of A, 4B,... But also in the vicinity of the tip thereof is activated, an emission region is formed in the entire area of the electron emitter 5, the glow arc transition time can be shortened, and ion sputtering occurs. Time can be shortened. Also, even after the exhaustion of the granules 51,... Of the electron emitters 5 around one of the electrode rods 4A and 4B, an arc spot is formed around the other electrode rods 4A and 4B, resulting in a long life.

FIGS. 17 to 19 show other embodiments of the hot cathodes 3J to 3L as an electrode assembly. In the drawings, the same parts as those in FIG. 2 are denoted by the same reference numerals and the description thereof is omitted. I do. The hot cathode 3J shown in FIGS.
2 to 3L have the container shapes shown in FIGS.
Is different from that shown in

FIG. 17 is a top view of a hot cathode 3J having conductivity. A container 6J shown in the hot cathode 3J has granules 51 of an electron emitter 5 with respect to an outer peripheral shape which is circular when viewed from above. The peripheral shape of the inner wall of the opening 62 for accommodating...

In the discharge lamp in which the hot cathode 3J is sealed, since the inner wall of the container 6J is made uneven, the circumference of the inner wall can be made longer than when the inner wall is simply made the same concentric circle as the outer wall. Of the granules 51,... When the lamp is energized, the absolute number of contact or proximity between the uneven peripheral edge 63 of the uneven inner wall 62 of the conductive container 6J and the granules 51 of the electron emitter 5 increases.

The discharge lamp is connected to the granules 51 of the electron-emitting body 5 which are in contact with or close to the uneven inner wall 62 of the container 6J, which is a conductive part, when energized.
An arc spot is generated from the granules 51 on the surface side, and when the electron emitting material in the granules 51 is scattered and consumed, the arc spot moves to the adjacent particles 51 to sustain the discharge.

As a result, the discharge easily occurs, the arc spot does not move significantly during lighting, and a stable discharge without fluctuation in the discharge can be maintained. In addition, the above lamp has a short transition time from glow discharge to arc discharge, can reduce a cathode drop voltage, can improve luminous efficiency, and can reduce spatters due to ion bombardment. Life can be extended.

FIG. 18 shows another hot cathode 3K. FIG. 18A is a top view, and FIG. 18B is a longitudinal sectional view. The container 6K of the hot cathode 3K has an outer peripheral shape that is circular when viewed from the top, and a peripheral shape of the inner wall of the opening 62 that stores the granules 51,... .

The hot cathode 3K has a circular protruding portion 64 which is integrally provided from the bottom of the circular container 6K toward the center of the opening, and has an annular recess 65 in the container 6K. The recesses 65 are filled with the granules 51 of the electron emitter 5 in an annular shape. In this case, the central projection 64
The arc spot, which is also a conductor and serves as a starting point of the discharge, can be generated in the entire extension of the inner wall 62 and the peripheral edge 35 of the protruding portion 64, and has the same effect as the above embodiment.

In the hot cathodes 3J and 3K shown in FIG. 17 and FIG. 18, the total extension length of the inner wall peripheral portions of the containers 6J and 6K is longer than a simple circular shape, and an arc spot is more likely to be generated, resulting in a longer time. This has the advantage that thermionic emission is performed over a period of time and the arc discharge can be sustained.

The shape of the container is not limited to a perfect circle, but may be an oval or a polygon such as a square or a rectangle, and the peripheral shape of the inner wall may have corrugated irregularities on the illustrated circular inner wall. The inner wall is not limited to the one formed, and the inner wall may have a polygonal shape such as an ellipse, a square, or a rectangle, and may have irregularities such as a wavy shape or a sawtooth shape. In addition, the shape of the central protruding portion 64 is not limited to a perfect circle, and one or more oval or polygonal shapes may be formed separately or continuously. Irregularities may be formed.

In the case of a circular container, for example, in the case of a circular container, the peripheral length L of the inner wall of the concave portion of the container and the projected area S of the opening have a relationship of L> 2 (π · S) ^1/2 . It is sufficient if the peripheral length of the inner wall of the container can be lengthened.

The hot cathode 3L shown in FIG.
The shape of L is different from that described above. That is, all of the above-mentioned ones have a cylindrical shape of the same diameter, but the container 6L has a larger diameter on the opening 62 side than on the bottom surface 61.

In the container 6L having the opening 62 side formed in a large-diameter trumpet shape, the outer periphery of the container 6L and the opening 72 of the holder 7L are in contact with each other, and the gap is apparently eliminated.
It is possible to prevent discharge from flowing into the space between the two through this gap.

Further, the container 6L has a configuration in which the granular electron emitter 5 composed of many granules 52,..., 53,. In the discharge lamp in which the hot cathode 3L is sealed, the arc discharge is stable, the flicker does not occur at the time of lighting, and the life can be extended.

Further, according to the study of the present inventors, in the discharge lamp shown in the above-described embodiment, the charged pressure of rare gas (Torr
r) and the average particle diameter D of the granules 51 of the granular electron emitter 5
(Μm) and the discharge current IL (mA),
It has been found that the transition from the glow discharge to the arc discharge can be promoted and the arc discharge can be stabilized for a long time.

That is, for example, the hot cathodes 3B, 3B shown in FIG. 5 are placed on both ends of a glass bulb 1 having a diameter of about 260 mm with an outer diameter of about 4 mm and a length of about 300 mm as shown in FIG. A fluorescent lamp having a fluorescent film formed on the inner surface of the bulb 1 and opposed thereto is filled with argon Ar as a rare gas together with the vapor of mercury Hg. It was manufactured by changing the average particle size.

An electron emitter 5 composed of an aggregate of granules 51 having a particle size of 10 to 100 μm is accommodated in a bottomed cylindrical container 6 constituting the hot cathode 3B. The container 6 and the granules 51 of the electron emitter 5 are made of an oxide of barium Ba and tantalum Ta and mainly composed of a small amount of zirconium oxide ZrO ₂ , and the surface thereof is improved in sputter resistance. For tantalum carbide Ta
C is coated with a thin film.

The results shown in Tables 3 to 5 were obtained by changing the gas pressure sealed in the bulb 1, the average particle size of the granules 51 of the electron emitter 5, and the discharge current. The average particle size mm was determined by the arithmetic mean of the particle size distribution. The sealed gas pressure is the total pressure of the sealed gas, for example, argon A
When r / neon Ne contains mercury vapor at room temperature at about 70 Torr at a total pressure, the charged gas pressure is about 70 Ton.
rr.

[0138]

[Table 3]

[Table 4]

[Table 5] Here, regarding the transition from glow discharge to arc discharge, when the time exceeds 1 second, x: when the time is within 1 second, o. When the life is less than 100 times, the result is x. When the life is more than 100,000 times, the result is o. Regarding the arc discharge during the life, granules 51 remain even though barium Ba remains on the surface of the particles 51.
X when discharging from other sources, barium Ba
In the case where the particles were discharged from the granules 51 while が remained, it was evaluated as ○.

If the pressure of the rare gas charged is PTorr, the average particle diameter of the granules 51 of the particulate electron emitter 5 is D μm, and the discharge current is IL mA, the relationship of P × IL / D ≧ 10 is obtained. In addition, the transition from the glow discharge to the arc discharge is promoted, the arc discharge is stabilized, and the blackening of the inner wall of the glass bulb 1 and the shortening of the life can be prevented.

In the above equation, the higher the filling gas pressure, the better. However, if the filling gas pressure increases depending on the specification conditions, the starting voltage will increase and the luminous efficiency will decrease. Therefore, the filling gas pressure is limited according to the specification conditions. . It should be noted that the same applies to the case where the sealed gas was tested with another gas, for example, a mixed gas of sodium Na, neon Ne and argon Ar, a mixed gas of barium Ba and argon Ar, and a mixed gas of barium Ba and xenon Xe. The result was able to be obtained.

Further, when a mixture of granular electron emitters 5 having different particle size distributions is used as the electron emission electrode structure, a discharge lamp which can easily perform dimming can be obtained.

That is, for example, the hot cathode 3 shown in FIG.
BaL and thallium oxide BaT are placed in the L container 6L.
Large and small 2 in average particle size distribution of semiconductor porcelain such as aO ₃
A plurality of thermionic emitters 5 having two peak values are filled and stored. The particle size distribution is relatively large, such as granules 52 having a peak at an average particle size of about 100 μm, and an average particle size of about 30 μm.
It is composed of a mixture of two types of granules 53 having a relatively small diameter with a peak at μm.
It is in the range from μm to 150 μm.

When the fluorescent lamp in which the hot cathodes 3L and 3L are sealed is turned on through a dimming circuit device (not shown), the lamp current without dimming is about 30 mA.
When the degree is about 1, one of the relatively large-diameter granules 52 having a particle diameter of about 100 μm among the electron-emitting members 5 housed in the container 6L.
An arc spot is generated in one or two pieces to maintain a stable discharge. However, in the case of granules 53 having a relatively small diameter of about 30 μm, an arc spot occurs over some of the particles, so that the heat storage structure is broken and the spots easily move to other granules. . Therefore, as a result, a stable arc spot is generated in the relatively large-diameter granules 52 having a particle size of about 100 μm.

When the fluorescent lamp is turned on with a current of about 5 mA for dimming, the particle size is about 30 μm.
An arc spot is generated in one or two of the relatively small-diameter granules 53 to maintain a stable discharge. However, since the relatively large-diameter granules 52 with a particle size of about 100 μm are larger than the relatively small-diameter granules 53 with a heat capacity of about 30 μm, the current is as low as about 5 mA. A sufficient amount of heat to emit thermoelectrons cannot be obtained. Therefore, as a result, a stable arc spot is generated on the relatively small-diameter granules 53 of about 30 μm from which the electron emission is easy.

Therefore, a discharge lamp using a mixture of electron emitters having different particle size distributions as described above raises the temperature of the electron emitter having a particle size at a peak corresponding to the lamp current to generate an arc spot. Can be done. Therefore, the present invention can be applied to a discharge lamp that performs dimming by current control corresponding to a current value, and can perform stable arc discharge and dimming.

The peak value of the particle size distribution is not limited to a mixture of two types, but may be three or more types.
The effect is greater when the difference between adjacent average particle diameter values is 1.5 times or more.

FIG. 20 is a perspective view showing an embodiment of the discharge lamp device 9 according to the present invention. FIG.
In the figure, reference numeral 91 denotes a housing.
2. Support member 9 such as a socket for supporting fluorescent lamp 1
3, 93 (one not shown) or power supply circuit device C
Is provided.

The discharge lamp device 9 is used for reading a backlight or a facsimile original of a liquid crystal display device. As described above, the fluorescent lamp 1 has improved light emission characteristics and has a long life. It has high characteristics and does not require replacement of the lamp 1 for a long period of time, thus facilitating maintenance.

Note that the present invention is not limited to the above embodiment. For example, in the electrode structure of the above-described embodiment, the granular electron emitter is accommodated in the container. However, the granular electron emitter is placed in a sintering container, and is taken out of the container after sintering. The electrode structure may be formed by connecting a lead wire or the like to the electrode structure, and the container functions as a means for supporting the electrode structure in the bulb or for electrically connecting the lead wire, but is not essential.

Further, even if the container constituting the hot cathode as the electrode assembly is made of the above-mentioned conductive metal,
It may be made of a semi-insulating so-called conductive ceramic in which a semiconductor porcelain material is mixed with a conductive metal, or may be made of a semiconductor porcelain material or an insulating material and the surface thereof is provided with conductivity. . In short, the present invention can be applied as long as it functions as a good conductor at the time of energization and can sufficiently flow through the electron emitter contained inside.

The discharge lamp is not limited to a fluorescent lamp,
The present invention can be applied to other discharge lamps such as an ultraviolet radiation lamp. Further, the discharge lamp may be a lamp that emits rare gas, and mercury may not be sealed as a discharge medium.
Also, the shape of the glass bulb is not limited to a straight tube shape,
It may be a lamp using a U-shaped, W-shaped or ring-shaped bent or plate-shaped bulb.

The number of electrodes provided on one discharge lamp is not limited to one pair (two) but may be three or more.
Also, the present invention can be applied to a lamp in which a part of the electrode is provided on the outer surface of the bulb.

Furthermore, the discharge lamp device is not limited to the configuration of the embodiment, and various modifications can be made to the shape and configuration. In addition, the housing described here is not limited to a box-shaped housing that accommodates a lamp and the like, but also includes a plate-shaped housing to which a lamp, a support member, and the like are exposed and attached. In the discharge lamp device, a power supply circuit device for lighting and a reflecting mirror may be provided separately and are not essential.

[0154]

According to the electron emission electrode structure of the first aspect, thermionic electrons can be rapidly emitted from the electron emitter composed of a plurality of granular aggregates, and an arc spot can be easily formed. And when this electrode assembly is used for a discharge lamp, it promotes the transition from glow discharge to arc discharge,
It is possible to provide a long-life electron emission electrode assembly that does not blacken the inner wall of the bulb and does not cause a short life.

According to the second aspect of the present invention, there is provided an electron emitting electrode assembly in which a plurality of granular electron assemblies are accommodated in a container having an opening.
The same effects as described in the above are exerted.

According to the electron emission electrode structure of the third aspect, the discharge is concentrated by providing a conductor in close proximity to or contact with the exposed surface of the electron emission body in the container, thereby achieving the same effect as in the second aspect. Effect.

According to the electron-emitting electrode structure of the fourth aspect, the use of a metal container facilitates the occurrence of electric discharge, and has the same effect as that of the third aspect.

According to the fifth aspect of the present invention, in the case of a metal container, the discharge concentrates on the opening side without discharging around the bottom surface of the container. It has the same effect as.

According to the electron emission electrode structure of the sixth aspect, even when an insulating container is used, the same effects as those of the second aspect can be obtained.

According to the seventh aspect of the present invention, the same effects as those of the second aspect can be obtained when a container made of a metal oxide is used.

According to the eighth aspect of the present invention, the container has high sputtering resistance, and has the same effect as that of the second aspect.

According to the ninth aspect of the present invention, since the container is electrically and mechanically connected to the holder, the same effects as those of the second aspect can be obtained.

According to the tenth aspect of the present invention, the provision of the metal projections concentrates the discharge, and has the same effect as the first aspect.

According to the eleventh aspect of the present invention, the discharge is concentrated by providing the tongue-shaped metal projections, and the same effect as described in the ninth aspect is achieved.

According to the electron emission electrode structure according to the twelfth to fourteenth aspects, the provision of the rod-shaped projections concentrates the discharge, and has the same effect as that of the first aspect.

According to the electron emission electrode structure of the fifteenth aspect, the discharge is concentrated by covering the opening of the container with the metal mesh, and the same effect as the second aspect is achieved.

According to the electron emission electrode structure of the sixteenth aspect, the discharge concentrating means is provided on the holder, and the same effects as those of the second aspect can be obtained.

According to the electron emitting electrode structure of the seventeenth aspect, it is an electron emitting material having a low work function, has a small cathode drop loss, and is easy to manufacture.

According to the electron emission electrode structure of the eighteenth aspect, the electron emission body has high sputtering resistance, and has the same effect as that of the second aspect.

According to the nineteenth aspect, the discharge lamp is provided at at least one end of the bulb.
Since the electrode according to any one of the above aspects is provided, the emission characteristics can be improved and the life can be extended.

According to the discharge lamp device of the present invention, the discharge lamp is used for reading a backlight or a facsimile of a liquid crystal display device. Therefore, these devices also have high light emission characteristics and do not require replacement of the lamp for a long period of time, which facilitates maintenance.

[Brief description of the drawings]

FIG. 1 is a partially cutaway plan view showing a fluorescent lamp according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a hot cathode which is an electrode of one embodiment of the present invention sealed in the fluorescent lamp of FIG. 1;

FIG. 3 is a graph showing a relationship between a discharge current (A) of a hot cathode having an insulator and a cathode drop voltage (V).

FIG. 4 shows the discharge current (A) of a hot cathode having no insulator
4 is a graph showing the relationship between the voltage and the cathode drop voltage (V).

FIG. 5 is a perspective view showing a hot cathode which is an electrode of another embodiment of the present invention.

6 is a graph showing the relationship between the input power (W) of the fluorescent lamp using the hot cathode shown in FIG. 5 and the reciprocal of the glow arc transition time τg (sec− ¹ ).

FIG. 7 is a plan view showing a hot cathode according to another embodiment of the present invention;

FIG. 8 is a side view of the hot cathode shown in FIG. 8;

FIG. 9 is a plan view showing a hot cathode according to another embodiment of the present invention;

FIG. 10 is a side view of the hot cathode shown in FIG. 9;

FIG. 11 is a plan view showing a hot cathode according to another embodiment of the present invention.

FIG. 12 is a side view of the hot cathode shown in FIG. 11;

FIG. 13 is a perspective view showing a hot cathode according to another embodiment of the present invention;

FIG. 14 is a perspective view showing a hot cathode according to another embodiment of the present invention;

FIG. 15 is a partial cross-sectional plan view of the fluorescent lamp using the hot cathode shown in FIG. 14;

FIG. 16 is a perspective view showing a hot cathode according to another embodiment of the present invention;

FIG. 17 is a top view showing a hot cathode according to another embodiment of the present invention;

FIG. 18 shows a hot cathode according to another embodiment of the present invention;
Is a top view, and (b) is a longitudinal sectional view.

FIG. 19 is a partially cutaway sectional view showing a hot cathode according to another embodiment of the present invention;

FIG. 20 is a perspective view showing the discharge lamp device of the embodiment.

[Explanation of symbols]

 1, 1A: Discharge lamp (fluorescent lamp) 2: Glass bulb 3A to 3L: Electron emission electrode assembly (hot cathode) 4: Lead wire 4A, 4B: Rod-like projection (electrode bar-conductor portion) 5: Electron emitter 51 : Granules 6, 6F, 6G, 6H, 6J, 6K, 6L: Containers 7A to 7D, 7J: Holder 73: Protrusion (conductive part) 74: Tongue piece 77: Rod-like projection (rod-conductive part) 78: Metal mesh (conductor part) 8: Insulator 9: Discharge lamp device 91: Housing 92: Support member

Claims (21)

[Claims] 1. An electron emitter made of an aggregate of granules heated by discharge to emit thermoelectrons from an exposed surface; and said exposed surface in contact with or in contact with at least a part of said exposed surface of said electron emitter. And a discharge concentrating means for concentrating a discharge on the electron emission electrode assembly. 2. An electron emitter made of an aggregate of granules heated by discharge to emit thermoelectrons from an exposed surface; and said exposed surface in close proximity to or in contact with at least a part of said exposed surface of said electron emitter. A discharge concentrating means for concentrating a discharge on the substrate; and a container for accommodating the electron-emitting body. 3. An electron emitter made of an aggregate of granules that are heated by electric discharge and emit thermoelectrons from an exposed surface; and an electron emitter that accommodates the electron emitter and is close to at least a part of the exposed surface of the electron emitter. Or a container that uses the contacting portion as a conductor to concentrate discharge on the exposed surface. 4. The electron-emitting electrode assembly according to claim 3, wherein said container is made of metal. 5. The electron emission electrode assembly according to claim 4, wherein an outer surface of the metal container is coated with an insulating material. 6. The electron emission electrode assembly according to claim 2, wherein the container is insulative or semi-insulating. 7. The electron emission electrode assembly according to claim 6, wherein the container is made of a metal oxide. 8. The container is made of a material mainly composed of at least one oxide of an alkaline earth metal, a transition metal and a rare earth metal, and has an alkaline earth metal, a transition metal and a rare earth metal on its surface. 7. The electron-emitting electrode structure according to claim 6, wherein at least one of carbide and / or nitride is formed. 9. The electron emission electrode assembly according to claim 2, wherein the container is supported by a holder. 10. The electron-emitting electrode assembly according to claim 1, wherein said discharge concentrating means is a metal protrusion approaching or in contact with at least a part of said exposed surface of said electron-emitting body. 11. The electron-emitting electrode assembly according to claim 10, wherein said metal projection has a tongue shape. 12. The electron emission electrode assembly according to claim 1, wherein said discharge concentration means is a rod-like projection penetrating through said electron emission body and projecting from said exposed surface. 13. The electron-emitting electrode assembly according to claim 11, wherein said rod-shaped projection projects from a center of said exposed surface. 14. The electron-emitting electrode assembly according to claim 12, wherein the rod-shaped projection projects eccentrically from the center of the exposed surface. 15. The electron emission electrode assembly according to claim 2, wherein the discharge concentrating means is a metal mesh that covers the opening side of the container. 16. The apparatus according to claim 1, wherein said discharge concentrating means is formed on said container or said holder.
15. The electron-emitting electrode assembly according to any one of 0 to 14. 17. The method according to claim 1, wherein the granules of the electron emitter are made of a material mainly composed of at least one oxide of an alkaline earth metal, a transition metal and a rare earth metal. 3. The electron emission electrode assembly according to 2. 18. A film of at least one of an alkaline earth metal, a transition metal and a rare earth metal, formed of a carbide and / or nitride on the surface of the granules of the electron emitter. The electron-emitting electrode assembly according to claim 1. 19. A glass bulb for enclosing a gas to be subjected to electric discharge; an electron emitter made of an aggregate of granules provided in the bulb and heated by the electric discharge of the gas to emit thermoelectrons from an exposed surface; An electron emission electrode assembly comprising: discharge concentrating means for concentrating a discharge on the exposed surface by approaching or contacting at least a part of the exposed surface of the electron emitter;
A discharge lamp comprising: 20. A glass bulb for enclosing a gas to be discharged to form a discharge path; and an aggregate of granules provided at an end of the glass bulb and heated by the discharge of the gas and emitting thermoelectrons from an exposed surface. An electron emission electrode assembly comprising: an electron emitter made of the above; and discharge concentrating means for concentrating a discharge on the exposed surface by approaching or contacting at least a part of the exposed surface of the electron emitter; and the electron emission electrode assembly And a power supply circuit device connected to the power supply circuit for applying a voltage between the electrode assemblies. 21. An electron emitter made of an aggregate of granules provided in a glass bulb for enclosing a gas to be discharged and heated by the discharge of the gas and emitting thermoelectrons from an exposed surface; A discharge lamp comprising: an electron emission electrode assembly comprising discharge concentrating means for concentrating a discharge on the exposed surface by approaching or contacting at least a part of the exposed surface; and a housing for accommodating the discharge lamp. A discharge lamp device.