JP2000123726A - Processing method for discharge lamp electrode and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply remove impurities such as carbon stuck when electrodes are manufactured by applying high-frequency electromagnetic waves from an electromag netic wave generating device provided around a container to one or more electrodes stored in the container for heating them. SOLUTION: Electromagnetic waves from an electromagnetic wave generating device 3 such as a domestic microwave oven are applied to the inside 2a of a container 2 made of quartz which is a nonconductive material not induction-heated by electromagnetic waves and a discharge lamp electrode 1 made of a conductor and sealed in it for induction heating. When an electric discharge 4 generated from the tip of the discharge lamp electrode 1 is continued for some time, impurities such as carbon are deposited on the inner surface of the quartz container 2 kept at the low- temperature state together with tungsten as deposits 2b. Gases of one or more kinds, e.g., rare gas suck as argon and hydrogen, are preferably sealed at the inside 2a of the quartz container 2 at the prescribed gas pressure, and a discharge phenomenon by electromagnetic induction easily occurs. The impurities contained in the discharge lamp electrode 1 may be deposited on a separately provided member by evaporating them via electromagnetic wave heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing apparatus for easily removing impurities, particularly carbon, adhering during the production of a discharge lamp electrode and providing a discharge lamp electrode suitable for a discharge lamp.

[0002]

2. Description of the Related Art Tungsten is mainly used as an electrode material for a discharge lamp. The production process is a process of putting a binder, powder pressing and sintering, drawing using a carbon die, electrolytic polishing the outer peripheral surface, cutting to the desired length, polishing and attaching the tip coil After that, a tungsten electrode for a discharge lamp is obtained. At this time, if the discharge lamp is incorporated into the discharge lamp in the state after the above-mentioned production process, the blackening of the discharge lamp occurs at an early stage as it is used, resulting in a short life of the discharge lamp and a decrease in luminous flux.

One of the major causes is that impurity carbon is mixed in the discharge lamp, and the carbon reacts with tungsten of the electrode to deposit tungsten carbide on the inner surface of the arc tube, causing blackening. Carbon originally exists as an impurity in the tungsten electrode, and therefore, before the discharge lamp is assembled, the tungsten electrode is treated for the purpose of removing impurities. On the other hand, conventionally, a tungsten electrode before being incorporated into a discharge lamp is degreased and washed with a detergent, and
Heat treatment in a furnace in a hydrogen atmosphere at 600 ° C.
A treatment method such as performing a final heat treatment in a furnace at 00 ° C. in a vacuum has been applied.

[0004]

However, in the conventional processing method, the temperature experienced by the tungsten electrode is lower than that in a state where the tungsten electrode is incorporated in an actual discharge lamp.
It was not possible to completely remove the carbon. In addition, sophisticated and complicated equipment such as a furnace for maintaining a high temperature was required, and the work was not easy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is possible to easily remove impurities, particularly carbon, adhering during production of a discharge lamp electrode and obtain a discharge lamp electrode suitable for a discharge lamp. It is an object to provide a method and an apparatus.

[0006]

In order to achieve the above object, according to the present invention, at least one electrode for a discharge lamp is provided therein.
An electromagnetic wave generator was provided around the container, and a high-frequency electromagnetic wave was generated from the electromagnetic wave generator and applied to a discharge lamp electrode inside the container to heat the discharge lamp electrode. The discharge lamp electrode inside the container is
Since the conductor is a conductor, it is heated based on the principle of induction heating by an electromagnetic field wave generated from the electromagnetic wave generator, and discharge phenomena are discharged from the discharge lamp electrode inside the container to the inside of the container by the principle of electromagnetic induction. Occurs. For this reason, the discharge lamp electrode placed in the phenomenon state according to the present invention is in the same state as the inside of the discharge lamp being lit, and is about 2,500.
Heat treatment is performed at a temperature of from 3000C to 3000C.

Further, in the present invention, the container is made of a non-conductive material. Accordingly, the temperature is much lower than that of the discharge lamp electrode because it is a non-conductive substance and is not affected by induction heating by electromagnetic waves. For this reason, the impurities of the discharge lamp electrode heat-treated at a high temperature, particularly carbon, evaporate and are deposited on the inner surface of the vessel having a lower temperature than the discharge lamp electrode together with tungsten which is a main component of the discharge lamp electrode. , Can be completely removed from the discharge lamp electrode.

According to a third aspect of the present invention, in the container,
At least one kind of rare gas or hydrogen is present together with the electrodes. This makes it possible to more easily cause a discharge phenomenon due to electromagnetic induction.

According to a fourth aspect of the present invention, impurities contained in an electrode for a discharge lamp are evaporated by heating the electrode by electromagnetic waves, and are removed from the electrode by vapor deposition on a member provided separately from the electrode. did. This makes it possible to easily remove impurities, particularly carbon, of the discharge lamp electrode, which is difficult to remove in the prior art. In the case of an electrode capable of evaporating contained impurities by heating with an electromagnetic wave, the contents of the present invention may be applied to an electrode for an electric lamp other than for a discharge lamp.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to make the present invention easier to understand, the present invention will be described in detail with reference to the following examples.

[0011]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention. In FIG. 1, a discharge vessel electrode 1 is disposed inside an electromagnetic wave generator 3 and a quartz container 2 completely sealed.
Is fixed. However, the description of the jig for fixing is omitted. Inside the quartz vessel 2a, the discharge lamp electrode 1 is present, and argon is kept at a gas pressure of 50 Torr. Although argon is used as the rare gas in this embodiment, other rare gases such as helium gas, neon gas, krypton gas, xenon gas, and radon gas, and hydrogen gas may be used. If you can also achieve the same effect,
Other gases may be used. Further, a plurality of gases may be used in combination.

[0012] The electromagnetic wave generator 3 controls the inside 2 of the quartz container.
a and the discharge lamp electrode 1. In the interior 2a of the quartz container to which the electromagnetic wave is applied, the discharge lamp electrode 1 as a conductor is heated by the principle of induction heating. At the same time, a discharge 4 is generated from the tip of the discharge lamp electrode 1. By continuing this phenomenon for several seconds to several minutes, impurities are removed from the discharge lamp electrode 1 by depositing the deposit 2b on the inner surface of the quartz vessel 2 having a lower temperature than the discharge lamp electrode 1. It is possible to do.

As the electromagnetic field generator 3 used to apply the electromagnetic wave, a microwave oven used in ordinary households may be used. In this embodiment, the discharge lamp electrode 1 is used.
And a quartz container 2 sealed with argon and 50 Torr were placed inside a general-purpose microwave oven (NEC MC-EV2 rated high-frequency output 500 W), and irradiated with electromagnetic waves at the maximum output for 6 minutes. Thereafter, the deposit 2b was deposited inside the quartz.

As shown in FIG. 2, as a result of qualitative analysis of the deposited matter 2b using an energy dispersive X-ray analyzer, tungsten, which is the main component of the discharge lamp electrode 1, and the discharge lamp electrode Carbon, one of the impurities, was detected.

FIG. 3 shows the results of elemental qualitative analysis before and after the treatment of the present invention. In the discharge lamp electrode 1 in which carbon was detected before the treatment, no carbon was detected after the treatment.

As described above, the discharge lamp electrode 1
Is placed in the same state as the inside of the discharge lamp being lit, and is heated at a temperature of about 2500 ° C. to 3000 ° C. Since the container is made of a non-conductive material, the temperature is much lower than that of the discharge lamp electrode without being affected by induction heating by electromagnetic waves. And the impurities of the discharge lamp electrode heat-treated at a high temperature, particularly carbon, evaporate and are deposited together with tungsten which is a main component of the discharge lamp electrode on the inner surface of the container having a lower temperature than the discharge lamp electrode, It is completely removed from the discharge lamp electrode.

[0017]

According to the present invention, the following effects are exhibited by the above configuration. The discharge lamp electrode according to claim 1, comprising a container accommodating at least one electrode for a discharge lamp therein, an electromagnetic wave generator provided around the container, and a high frequency electromagnetic wave generated by the electromagnetic wave generator. To heat the discharge lamp electrode and, by the principle of electromagnetic induction, cause a discharge phenomenon inside the container from the discharge lamp electrode inside the container, and the same state as inside the discharge lamp being lit. By performing the heat treatment at a temperature of about 2500 ° C. to 3000 ° C., impurities contained in the discharge lamp electrode can be evaporated.

According to the second aspect of the present invention, the container is made of a non-conductive material, so that the container is not affected by induction heating by electromagnetic waves and has a very low temperature as compared with the discharge lamp electrode existing inside the container. Discharge electrode impurities,
Particularly, carbon evaporates and is deposited together with tungsten which is a main component of the discharge lamp electrode on the inner surface of the container having a lower temperature than the discharge lamp electrode, so that impurities are completely removed from the discharge lamp electrode. It becomes possible.

According to the third aspect of the present invention, the presence of at least one kind of inert gas together with the electrode inside the container makes it easier to cause a discharge phenomenon by electromagnetic induction, and more effectively removes impurities from the discharge lamp electrode. Can be removed.

According to the present invention, impurities contained in the electrode for the discharge lamp are evaporated by heating the electrode by electromagnetic waves, and are removed from the electrode by vapor deposition on a member provided separately from the electrode. Therefore, impurities can be easily removed from the discharge lamp electrode.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 shows the results of elemental qualitative analysis of the deposits obtained in the examples.

FIG. 3 shows the results of elemental qualitative analysis of electrodes for a discharge lamp before and after the treatment according to the present invention obtained by the examples.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electrode for discharge lamp 2 ... Quartz container, 2a ... Inside of quartz container, 2b ... Adhered matter 3 ... Electromagnetic wave generator 4 ... Discharge

Claims (4)

[Claims] 1. An electrode for a discharge lamp inside a container, comprising a container in which at least one electrode for a discharge lamp is housed inside, an electromagnetic wave generator provided around the container, and a high-frequency electromagnetic wave generated by the electromagnetic wave generator. A discharge lamp electrode heating apparatus for heating a discharge lamp electrode. 2. The apparatus according to claim 1, wherein the container is made of a non-conductive material. 3. An apparatus for treating an electrode for a discharge lamp according to claim 1, wherein at least one kind of rare gas or hydrogen is present inside said container together with said electrode. 4. A discharge lamp, wherein impurities contained in an electrode for a discharge lamp are evaporated by heating the electrode by electromagnetic waves, and are removed from the electrode by vapor deposition on a member provided separately from the electrode. Treatment method for electrodes.