JPH1055784A - Electrodeless discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrodeless discharge lamp with high starting capability. SOLUTION: An electrodeless discharge lamp has an arc tube 1, an induction coil 3, a high frequency power source 4, a starting auxiliary electrode 5, and a high voltage power source 6, the arc tube 1 is formed in almost a globular shape with a translucent material, and a discharge gas is sealed on its inside. The induction coil 3 is wound in close vicinity to the outer circumferential surface around the maximum diameter part of the arc tube 1, and its both ends are connected to the high frequency power source 4. The material of the induction coil 3 is silver alone or an alloy of silver and nickel, and the outer circumferential surface 3a is coated with a radioactive material such as a single material or a compound of Pr, Th, or Cs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge gas filled in an arc tube without an electrode inside the arc tube.
The present invention relates to an electrodeless discharge lamp in which a discharge gas is excited and emits light by applying a high-frequency electromagnetic field from the outside.

[0002]

2. Description of the Related Art Conventionally, a high-frequency current is applied to an induction coil wound around an arc tube, thereby causing a high-frequency electromagnetic field generated around the induction coil to be discharged from a discharge gas sealed in the arc tube. An electrodeless discharge lamp has been proposed in which an electrodeless discharge is generated by causing it to act to excite and ionize a discharge gas to emit light. This type of electrodeless discharge lamp has features such as small size, high efficiency, and long life, and is being researched and developed in various places.

As this type of electrodeless discharge lamp, as shown in FIG. 6, a substantially spherical arc tube 1 filled with a discharge gas is provided.
An induction coil 3 wound around the outer surface of the arc tube 1; and a high-frequency power supply 4 for supplying a high-frequency current to the induction coil 3; An auxiliary electrode 5 and a high voltage power supply 6 for applying a high voltage to the auxiliary electrode 5 are provided.

In order to further increase the efficiency, the arc tube is arranged inside the outer tube to form a so-called double tube structure, and the inside of the outer tube is evacuated to raise the operating temperature. An electrode discharge lamp is disclosed, for example, in US Pat.
No. 50,015.

FIG. 7 shows an electrodeless discharge lamp having a double tube structure. This electrodeless discharge lamp has a substantially spherical arc tube 1 in which a discharge gas is sealed, and is closed around the arc tube 1. A high-frequency power supply for supplying a high-frequency current to the induction coil, comprising: a substantially cylindrical outer tube provided to form a space; and an induction coil wound around the outer surface of the outer tube. 4 is provided. The inside of the outer tube 2 forming the closed space is vacuum. Reference numeral 5 denotes a starting auxiliary electrode, reference numeral 6 denotes a high-voltage power supply, and reference numeral 7 denotes a getter member (see Japanese Patent Application Laid-Open No. H8-17405).

[0006]

However, the conventional electrodeless discharge lamp constructed as described above has a problem that it is difficult to start because it does not have a mechanism for generating electrons in the arc tube 1 at the time of starting. There is.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electrodeless discharge lamp having excellent startability.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an arc tube, an induction coil wound around the arc tube, and a high frequency power supply for supplying a high frequency current to the induction coil. In an electrodeless discharge lamp equipped with, or an arc tube, an outer tube provided to secure a closed space around the arc tube, an induction coil wound around the outer tube, and an induction coil In an electrodeless discharge lamp having a high-frequency power supply for supplying a high-frequency current, or in an electrodeless discharge lamp in which a getter member is added to a closed space formed by an arc tube and an outer tube, the induction coil, the arc tube, or the outer tube A radioactive material is applied to part or the getter member.

In the case where a heat insulating film is formed on the arc tube or the outer tube so as to prevent heat in the arc tube from escaping or a reflective film is formed to increase the luminous flux, the heat insulating film or the reflective film is not used. You may comprise using what added the radioactive material to the film material.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 shows a first embodiment of an electrodeless discharge lamp according to the present invention. This electrodeless discharge lamp comprises an arc tube 1, an induction coil 3, a high-frequency power supply 4, a starting auxiliary. An electrode 5 and a high-voltage power supply 6 are provided.

The arc tube 1 is formed in a substantially spherical shape by using a translucent material such as quartz glass. Inside the arc tube 1, a rare gas and metal halide is enclosed as a discharge gas, as a discharge gas, for example, NdI _3-CSI (neodymium iodide xenon gas and 20mg of 100 Torr, a mixture of Seshiumuyou iodide ) Was used. The shape of the arc tube 1 need not be spherical, but may be other shapes such as a cylindrical shape.

The induction coil 3 is disposed so as to be wound close to the outer peripheral surface of the arc tube 1 centered on the maximum diameter portion, and both ends thereof are connected to the high frequency power supply 4. The number of turns of the induction coil 3 is not particularly limited as long as it is wound one or more turns. In this embodiment, the number of turns is three. The induction coil 3 may be wound so as to be in contact with the outer surface of the arc tube 1 or may be wound with a gap provided between the induction coil 3 and the outer surface of the arc tube 1 as in the present embodiment.

The material of the induction coil 3 is a simple substance of silver or an alloy of silver and nickel, and a radioactive material, for example, a simple substance or a compound such as Pr, Th, or Cs is applied to the outer peripheral surface 3a. The location where the radioactive material is applied may be on any surface of the induction coil 3 or may cover the entire coil.

The starting auxiliary electrode 5 has an arc tube 1 at its tip.
And the other end thereof is connected to a high-voltage power supply 6 for generating a high-voltage pulse.

In the electrodeless discharge lamp thus configured, when the high-frequency power supply 4 is operated, a high-frequency current flows through the induction coil 3 and an electromagnetic field is generated around the induction coil 3.
The discharge inside the arc tube 1 is maintained by this electromagnetic field. During the maintenance of the discharge, the electrons inside the arc tube 1 receive the kinetic energy by the electromagnetic field, collide with the discharge gas atoms to give energy, and the discharge gas atoms are ionized or excited. The excited atoms emit light when returning to the ground state, and the emitted light is used as light energy.

In this embodiment, as described above, since it is difficult to start discharge only with the induction coil 3, the starting is performed while applying a high voltage pulse to the starting auxiliary electrode 5. Since the radioactive material is applied to a part of the light-emitting material, the radiation emitted from the radioactive material is supplied into the arc tube 1 to ionize the atoms of the discharge gas in the arc tube 1 to generate electrons. Electrons in the arc tube 1 are accelerated by an electric field generated between the auxiliary electrode 5 and the induction coil 3, and collide with atoms of the discharge gas to ionize them, thereby generating new electrons. Therefore, the ionization due to the radiant energy can be used, and the starting becomes easier.

As described above, according to the present invention, more electrons are generated at the start of discharge, so that dielectric breakdown easily occurs, and the voltage value applied to the starting auxiliary electrode 5 can be reduced. Therefore, it is possible to provide an electrodeless discharge lamp having better startability.

In order to confirm this, the inventors of the present application have proposed a conventional electrodeless discharge lamp (see FIG. 6) in which the induction coil 3 is not coated with a radioactive material, and an electrodeless discharge lamp according to the present embodiment. Were compared. The method uses induction coil 3
Was fixed at 100 W, the voltage value of the pulse applied to the starting auxiliary electrode 5 was increased, and the average voltage when discharge occurred in the arc tube 1 was measured. As a result, the voltage was about 24.0 kV in the conventional electrodeless discharge lamp, whereas it was 21.5 kV in the electrodeless discharge lamp according to the present embodiment.
V, and it was confirmed that the value decreased by about 10.4%.

(Embodiment 2) FIG. 2 shows a second embodiment of the present invention. The difference from Embodiment 1 is that instead of applying a radioactive material to the induction coil 3, an auxiliary for starting is used. Since the radioactive material is applied to the tip 5a of the electrode 5, that is, the side in contact with the arc tube 1, the other configuration is the same as that of the first embodiment. .

With this configuration, the radiation emitted from the radioactive material applied to the tip 5a of the auxiliary electrode 5 is supplied into the arc tube 1 to ionize the atoms of the discharge gas in the arc tube 1 and generate electrons. Occurs. That is, since more electrons are generated at the start of discharge, dielectric breakdown easily occurs, and the voltage value applied to the auxiliary electrode 5 also decreases.

In order to confirm the effect, measurement was performed by the same method as described above.
It turned out to be 0.0 kV, which is a value reduced by about 16.7%.

(Embodiment 3) FIG. 3 shows a third embodiment of the present invention. The difference from Embodiment 1 is that instead of applying a radioactive material to the induction coil 3, an arc tube 1 is used. Since a radioactive material is applied to a part 1a of the outer surface of the second embodiment, the other configuration is the same as that of the first embodiment.

In this embodiment, the auxiliary electrode 5 is provided on the outer surface of the arc tube 1 where the induction coil 3 is not wound.
Although the radioactive material was applied to the portion where the contact was made, the present invention is not limited to this.
May be applied to the outer surface of the arc tube facing the above or the outer surface of the arc tube around which the induction coil 3 is wound. In addition, the arc tube has a powder coating of alumina, silica, and magnesia to form a heat insulating film for preventing heat inside the arc tube from escaping, and a reflector film for increasing the luminous flux. A radioactive material may be mixed with these powders.

With this configuration, the arc tube 1
The radiation emitted from the radioactive material applied to a part 1a of the outer surface 1a is supplied into the arc tube 1, acts in the same manner as described above, and obtains the same effects as described above. It was confirmed that the average voltage of the electrodeless discharge lamp according to the present embodiment was 20.5 kV, which was about 14.6% lower than that of the conventional lamp.

(Embodiment 4) FIG. 4 shows a fourth embodiment of the present invention. The difference from the above embodiments is that the present invention is applied to an electrodeless discharge lamp having a double tube structure shown in FIG. Applying the invention, the getter member 7 disposed in the outer tube 2
Is that a radioactive material was applied.

The outer tube 2 is formed of a translucent material such as quartz glass so as to secure a closed space around the arc tube 1 and has a substantially cylindrical shape. Housed and evacuated to vacuum. The arc tube 1 is held in the outer tube 2 by a hollow support 8a formed to protrude inward from one end of the outer tube 2. The support body 8a is open at one end of the outer tube 2, and the tip 8b is welded to the outer surface of the arc tube 1. At this welded portion, the arc tube 1 passes through the outer tube of quartz glass constituting the arc tube 1 through one layer. It is connected to 2 external spaces.

An auxiliary starting electrode 5 is provided in the hollow portion of the support 8a, and its tip is in contact with the outer surface of the arc tube 1 and the other end is connected to the high voltage power supply 6. Further, a getter member 7 for adsorbing impurity gas is provided in a closed space formed by the arc tube 1 and the outer tube 2, and the getter member 7 is coated with a radioactive material as described above. ing. In addition, on the outer surface of the outer tube 2, similarly to the conventional example,
The induction coil 3 is wound, and both ends are connected to the high frequency power supply 4.

With this configuration, the radiation emitted from the radioactive material applied to the getter member 7 is supplied into the arc tube 1 to ionize the atoms of the discharge gas in the arc tube 1 to generate electrons. . In other words, since more electrons are generated at the start of discharge, dielectric breakdown easily occurs,
The voltage value applied to the auxiliary electrode 5 also decreases.

In order to confirm the effect, the measurement was performed by the same method as described above. As a result, the conventional electrodeless discharge lamp was about 24.0 kV, whereas the electrodeless discharge lamp according to the present embodiment was 2 kV.
It turned out to be 0.3 kV, which is a value reduced by about 15.4%.

(Embodiment 5) FIG. 5 shows a fifth embodiment of the present invention. The difference from the fourth embodiment is that the inner surface of the outer tube 2 or a part 2a of the outer surface is provided with radioactive rays. Since the other configuration is the same as that of the first embodiment due to the application of the material, the description is omitted by assigning the same reference numerals to the same configuration.

With this configuration, radiation emitted from the radioactive material applied to the inner surface or a part 2a of the outer surface of the outer tube 2 is supplied into the arc tube 1 and acts in the same manner as described above. Similar effects can be obtained. It was confirmed that the average voltage of the electrodeless discharge lamp according to the present embodiment was 21.0 kV, which was about 12.5% lower than that of the conventional lamp.

The application position of the radioactive material is not limited to the inner surface or the outer surface of the outer tube 2 on the support 8a side as in the present embodiment. For example, the inner surface or the outer surface of the outer tube 2 on the opposite side is not limited. It may be applied to the outer surface or to the inner or outer surface of the outer tube 2 facing the induction coil 3. In addition, there is an outer tube coated with alumina, silica, and magnesia powder to form a heat insulating film for preventing heat inside the arc tube from escaping to the outside, and a type formed with a reflective film for increasing luminous flux. A radioactive material may be mixed with these powders.

[0033]

According to the present invention, as described above, radiation emitted from a radioactive material is obtained by applying a radioactive material to an induction coil, a part of an arc tube or an outer tube, or a getter member in an electrodeless discharge lamp. Is supplied into the arc tube,
The atoms of the discharge gas in the arc tube are ionized to generate electrons.
That is, since more electrons are generated at the start of discharge, dielectric breakdown in the generation tube is likely to occur, and an electrodeless discharge lamp with good startability can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing a third embodiment of the present invention.

FIG. 4 is a schematic diagram showing a fourth embodiment of the present invention.

FIG. 5 is a schematic diagram showing a fifth embodiment of the present invention.

FIG. 6 is a schematic diagram showing a conventional example.

FIG. 7 is a schematic diagram showing a different conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arc tube 2 Outer tube 3 Induction coil 4 High frequency power supply 5 Starting auxiliary electrode 6 High voltage power supply 7 Getter member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takuma Hashimoto 1048 Odakadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd.

Claims (7)

[Claims] An arc tube made of a translucent material filled with a discharge gas, an induction coil wound around the arc tube, and a high-frequency power supply for supplying a high-frequency current to the induction coil. An electrodeless discharge lamp, wherein a radioactive material is applied to a part of the induction coil. 2. An arc tube made of a translucent material filled with a discharge gas, an induction coil wound around the arc tube, and a high-frequency power supply for supplying a high-frequency current to the induction coil. In an electrodeless discharge lamp, a starting auxiliary electrode whose tip is in contact with the outer surface of the arc tube is provided, and a radioactive material is applied to the tip of the auxiliary electrode. 3. A radioactive material is applied to a part of the outer surface of the arc tube instead of the induction coil.
An electrodeless discharge lamp as described. 4. An arc tube made of a translucent material filled with a discharge gas, an induction coil wound around the arc tube, and a high-frequency power supply for supplying a high-frequency current to the induction coil. An electrodeless discharge lamp, wherein a radioactive material is added to a heat insulating film or a reflection film provided on the arc tube. 5. An arc tube made of a translucent material filled with a discharge gas, an outer tube made of a translucent material provided to secure a closed space around the arc tube, and the outer tube. An electrodeless coil provided with an induction coil wound around the coil and a high-frequency power supply for supplying a high-frequency current to the induction coil, and a getter member for adsorbing impurity gas in a closed space formed by the arc tube and the outer tube. An electrodeless discharge lamp, wherein a radioactive material is applied to the getter member. 6. An arc tube made of a translucent material filled with a discharge gas, an outer tube made of a translucent material provided to secure a closed space around the arc tube, and the outer tube. An electrodeless coil provided with an induction coil wound around the coil and a high-frequency power supply for supplying a high-frequency current to the induction coil, and a getter member for adsorbing impurity gas in a closed space formed by the arc tube and the outer tube. An electrodeless discharge lamp, wherein a radioactive material is applied to an inner surface or a part of an outer surface of the outer tube. 7. An arc tube made of a translucent material filled with a discharge gas, an outer tube made of a translucent material provided to secure a closed space around the arc tube, and the outer tube In an electrodeless discharge lamp provided with an induction coil wound around and a high-frequency power supply for supplying a high-frequency current to the induction coil, a radioactive material is added to a heat insulation film or a reflection film provided on the outer tube. An electrodeless discharge lamp characterized in that: