JPS59169053A - Electrodeless electric-discharge lamp - Google Patents

Abstract

PURPOSE:To obtain an electrodeless electric-discharge lamp which can easily start to fire and gives no bad influence to human bodies and in which any reduction in luminous efficiency can be prevented by charging a light-transmitting case with a rare gas, Hg, a luminous matter and ceramic bodies in which a radioactive matter with a specific half life is dispersed and sealed. CONSTITUTION:An electrodeless electric-discharge lamp 7 is constituted by charging a light-transmitting case with a starting rare gas, Hg, a luminous matter and ceramic bodies in which a radioactive matter with a half life of 0.5-10 years is dispersed and sealed. For instance, microwaves produced by a magnetron 1 and discharged from a magnetron antenna 2 through a waveguide 3 into a cavity 4, form an electromagnetic field in the cavity 4. Due to the electromagnetic field, a rare gas charged in the electric discharge lamp 7 discharges to heat the wall of the lamp 7, and the charged metal evaporates to produce metallic vapor electric discharge thereby achieving a stable condition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electrodeless discharge lamp using microwave discharge.

[Technical background of the invention and its problems]

Conventionally, a discharge lamp generally has a pair of electrodes facing each other and utilizes light generated by a discharge occurring between the electrodes. However, this type of discharge lamp inevitably has disadvantages such as a decrease in light output due to consumption of the electrode material, blackening of the inner surface of the discharge lamp tube due to evaporation and scattering of the electrode, and a decrease in the characteristics of the electrode itself. there were.

In order to improve these drawbacks, in recent years, electrodeless discharge lamps excited by high-frequency discharge, particularly high-frequency microwaves, have begun to be put into practical use. Since this discharge lamp does not have electrodes, it has the advantage of having a longer life than the conventional discharge lamps having electrodes.

As an example of a device for lighting an electrodeless discharge lamp, there is one disclosed in Japanese Patent Application Laid-Open No. 57-172649. That is, as shown in Figure 1, the microwaves generated by the magnetron (1) are transmitted to the magnetron antenna (
Sj) k is radiated into the waveguide (3).

It is radiated into the cavity (4) through the feed port (6) and the cavity (
4) Form a microwave electromagnetic field within. Due to this electromagnetic field, the starting rare gas sealed in the electrodeless discharge lamp (7) is discharged, the discharge lamp wall is heated, the sealed metal evaporates, and a metal vapor discharge becomes a stable state. .

At this time, light is emitted with an emission spectrum unique to the metal depending on the type of metal encapsulated. In order to effectively utilize this light emission, the cavity wall (5) is used as a light reflector, and the front surface is made of, for example, a metal mesh plate aD that transmits light but does not transmit microwaves.

Emit light forward. In addition, the magnetron (1) is cooled by a cooling fan (8) provided in the two-box body (121).

Furthermore, this cooling air flows through the air pipe (9), the air blower, and the waveguide (
3), guided into the cavity (4) via the power supply port (6),
The structure is such that after the electrodeless discharge lamp (7) is cooled, it is discharged from the mesh plate 0υ.

However, since this type of discharge lamp has no electrodes, it is difficult to start the discharge simply by exciting it with microwaves.As a countermeasure, for example, Japanese Patent Laid-Open No. 58-25073 discloses that a natural radioactive element is added to the arc tube. A means of encapsulation is disclosed. However, natural radioactive elements have very long decay constants, that is, half-lives of about 10 θ years, and therefore a large amount of radioactive elements, on the order of several square meters, is required to obtain the necessary initial electrons. However, when radioactive elements, especially when handled in large quantities, can cause radiation damage to the human body.

It also reacts with the luminescent metal sealed in the arc tube, such as rare earth metals such as scandium iodide, and if the amount is large, the amount of luminescent metal will inevitably decrease, resulting in a decrease in light efficiency.
There are drawbacks such as short lifespan.

[Purpose of the invention]

The present invention has been made to address the above drawbacks.

It facilitates the start of discharge and has no adverse effects on the human body.
It is an object of the present invention to provide an electrodeless discharge lamp which can also prevent a decrease in light efficiency.

[Summary of the invention]

The present invention uses a rare gas and mercury in a light-transmitting container of a discharge lamp.

It is an electrodeless discharge lamp that encloses a ceramic body in which a radioactive substance with a half-life of 0.5 to 10 years is dispersed and sealed together with a luminescent substance.

[Embodiments of the invention]

The following two aspects of the present invention will be described with reference to one embodiment. Argon gas is applied at 100 torr as a rare gas for starting the inside of a transparent container, such as a quartz container, with an internal volume of about 14 c*c.
, mercury per 1 cec of the internal volume of the container 3 X 1
0-'gram atom 9 As a luminescent substance, a metal compound such as dysprosium iodide is used as dysprosium iodide l c
Enclose in an amount such that 0.2 x 10 gram atoms per ac, and in addition to these inclusions, have a half-life of 0.5 years to
Radioactive substances that last about 10 years, such as promethium 147 (
A discharge lamp is produced by additionally enclosing a ceramic body in which Pm) is dispersed and sealed.

By the way, radioactive substances with short half-lives such as (Pm) tend to have an adverse effect on the human body, and must be handled with great care.

In other words, if radioactive materials come into contact with the human body, they will cause radiation damage, so radioactive materials must be handled as sealed radiation sources to prevent them from scattering. Sealing means that the radiation source does not peel off in a smear test, that is, when the radiation source is wiped with a filter paper and the surface of the filter paper is examined to see if radiation is emitted using a counter, no radiation is detected. This means that the radiation must not migrate from the source to the filter paper.

Since the (Pm) is dispersed and sealed in the ceramic body, it does not easily peel off from the ceramic body and does not come off in a so-called smear test, so there is no risk of it adhering to the human body.

It is also safe to handle.

Install such an electrodeless discharge lamp in the position of the electrodeless discharge tube (7) in the lighting device shown in Figure 1, support the discharge tube with a suitable support (not shown), and light it up as described above. When the device is activated, radioactive substances (Pm) sealed inside the discharge tube are released.
The initial electrons emitted from the argon gas ionize the argon gas in the vicinity and generate electrons. On the other hand, magnetron (1)
The microwaves generated are radiated into the cavity (4) and a microwave electromagnetic field is formed within the cavity (4), and the electrons are accelerated by the excitation effect of this electromagnetic field and are discharged into the discharge lamp (7). ) and can be easily started.

The relative value of the discharge starting voltage due to microwave excitation of the discharge lamp of the present invention is 115 or less compared to conventional electrodeless discharge lamps that do not use a radioactive substance dispersed ceramic body, and the time required for starting discharge is less than 1/100. Unlike the conventional electrodeless discharge lamp, which required 5 minutes to manufacture, the discharge lamp of the present invention was able to start discharge instantly.

Moreover, since the radioactive material is sealed in a ceramic body, there is no danger to the human body when handling it.

Furthermore, even if radioactive materials are handled in the form of a sealed source, the law restricts the amount of radioactivity to less than 100 microcuries, so the amount of radioactivity per discharge lamp must be less than 100 microcuries. It is necessary to keep it.

Furthermore, if a radioactive substance with a half-life of 0.5 to 10 years is used, the amount required to start an electrodeless discharge lamp would be several square meters in the case of the conventional natural radioactive element mentioned above. It requires only a few ng (nanograms), which is an extremely small amount, and the radioactive material is sealed in a sealed radiation source that is dispersed in ceramic.

Ceramic prevents the reaction between luminescent metals and radioactive substances,
First, a reaction between the two does not occur, but even if a reaction occurs, the amount of the radioactive substance is extremely small, so naturally the amount of the luminescent metal that reacts with it will also be small.

Therefore, disadvantages such as a decrease in optical efficiency and a shortened lifespan can be avoided.

Note that if the radioactive substance has a half-life of less than 0.5 years, the attenuation is rapid and the attenuation is completed during the life of the discharge lamp, resulting in a significant drop in starting performance at the end of the life. On the other hand, if the half-life is too long, it will take time for the radiation to decay, resulting in poor startability, and it will be necessary to encapsulate a large amount of radioactive material. However, it is desirable for radioactive substances to decay to the extent that they do not have a negative impact on the living environment in about 100 years, and if we assume that if they decay to about □ in 100 years, it will be 000, then their half-life will be about 10 years. becomes.

In addition, examples of radioactive substances with a half-life of about 0.5 to 10 years include carbon-14 (C) and sodium-22 ("
Na), Calcilla A 45 (45Ca), Iron 55 (5
5Fe), cobalt 6o (60Co), = TS)
y /l/ 63 (”Ni).

Zinc 65 ("Zn), Mygay 54 ("Mn)
, Staythium 90 (90Sr), Ruthenium 10
6 (”'Ru), silver 110 (Ag), antimony 12
5 (Sb), cesium-134 (Cs), cesium l
37 (Cs), Valiu A 133 (Ba), *Liu A 144 (Ce).

tetramethium-147 (Pm), europium-154 (
154Eu), europium 155 (''Eu), gold 195 (195Au), Tariq A 204 (20'T
#), actinium-227 (Ac), americium-24
1 (Am), -+Yuriram 242 (Cm), $z
Tarik 244 ('''Cm), Kaliforniv A 25
2 (Cf), lead 21010 (pb), radium 226 (Ra), radium 228
(228Ra), )gram 228 (228Th), etc., is preferably selected and used.

Also.

Ceramics include nonmetallic oxides such as silicon oxide,
Metal oxides such as aluminum oxide, sodium oxide, magnesium oxide, beryllium oxide, titanium oxide, and calcium oxide; metal carbides such as aluminum carbide, sodium carbide, and calcium carbide; metal nitrides such as aluminum nitride, sodium nitride, and magnesium nitride, etc. is used.

Furthermore, in the above embodiment, a metal halide was sealed as a luminescent material in a quartz container, but the present invention is not limited thereto. It can also be applied to an electrodeless discharge lamp etc. sealed in a translucent ceramic container.

〔Effect of the invention〕

As detailed above, according to the present invention, a radioactive material-dispersed ceramic body having a half-life of about 0.5 to 10 years is enclosed in an electrodeless discharge lamp.

It has the advantage that it is possible to start the discharge very easily, has no adverse effect on the human body, and can also prevent a decrease in light efficiency.

[Brief explanation of drawings]

The figure shows an example of a lighting device for an electrodeless discharge lamp. (1)・・・Magnetron, (4)・・・・・・
Hollow body. (7)... Electrodeless discharge lamp, aυ...
Metal mesh plate. Agent: Patent attorney Kensuke Chika (and 1 other person)

Claims (1)

[Claims] In an electrodeless discharge lamp that emits light when excited by microwaves, the discharge lamp has a radioactive substance with a half-life of 0.5 to 10 years dispersed together with a rare gas, mercury, and a luminescent substance in a translucent container. An electrodeless discharge lamp characterized by encapsulating a sealed ceramic body.