JPH07182910A - Microwave discharge light source device - Google Patents

Abstract

PURPOSE:To make it difficult that generated impurity adheres to the inner surface of a lamp container by air-tightly penetrating a lamp container, where an electric discharging light emitting substance is contained, by a cooling pipe, and flowing a cooling medium inside the cooling pipe. CONSTITUTION:When a microwave oscillator 1 is operated to output microwave power is supplied to a microwave resonance cavity 3 from a power supply port 4 via a waveguide 2. The microwave supplied into the cavity 3 resonate inside, thus exciting an electric discharging light emitting substance inside a lamp container 6. Accordingly, the electric discharging light emitting substance inside the lamp container emits light, which is output outside through a metal mesh 5. When a circulation pump 11 is operated simultaneously with the operation of the oscillator 1, a cooling pipe 7 penetrating the container 6 can be maintained at a sufficiently low temperature in comparison with the container 6 even when the inside temperature of the lamp container 6 is increased. Impurity generated at that time can be adhesively accumulated on the surface of the cooling pipe 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave discharge light source device for exciting a discharge luminescent material in a lamp vessel with microwaves to emit light.

[0002]

2. Description of the Related Art Recently, as a light source device for generating ultraviolet rays, a microwave discharge light source device has been put into practical use in place of a conventional DC discharge excitation mercury lamp. The microwave discharge light source device can select the characteristics of the light generated depending on the type of the discharge luminescent material contained in the lamp container.

For example, if a mixed gas of a rare gas and a fluoride is used as the discharge luminescent material, it is possible to output light having a wavelength in the ultraviolet range, so that the light is produced by a semiconductor process such as a plasma process, etching or ashing. It is attracting attention because it can be applied to processes.

Generally, the microwave discharge light source device has a microwave oscillator for oscillating a microwave. The microwave oscillated from this oscillator is guided from the waveguide into the microwave resonant cavity through the feed port. Inside the microwave resonant cavity, a transparent lamp container in which a discharge luminescent material is enclosed is arranged. When the microwave is introduced into the microwave resonant cavity from the power supply port, the luminescent substance is excited and discharges and emits light.

When the luminescent material is a fluorine-based mixed gas, it is excited by microwaves to activate the fluoride and generate radicals and ions, which causes an etching action in the lamp container. Thereby, the inner surface of the lamp vessel is etched. The lamp vessel is usually made of quartz. Therefore, the impurities of SiF ₄ mainly generated by the etching action adhere to the inner surface of the lamp container, so that the light transmittance of the lamp container is significantly reduced, which may cause a reduction in output.

[0006]

Thus, when the discharge luminescent material contained in the lamp vessel is excited and activated, an etching action occurs, and the impurities generated by the etching action adhere to the inner surface of the lamp vessel. There was a case that the output was lowered.

The present invention has been made in view of the above circumstances. An object of the present invention is to prevent the impurities generated by the excitation of the discharge luminescent material from adhering to the inner surface of the lamp container. An object is to provide a discharge light source device.

[0008]

To solve the above problems, the present invention provides a microwave oscillator for oscillating a microwave, a waveguide for guiding the microwave oscillated by the microwave oscillator, and a waveguide for the same. A microwave resonant cavity body connected to the tube through a power supply port, a lamp vessel provided in the microwave resonant cavity body, and containing therein a discharge luminescent substance that is excited by the microwave and discharges and emits light.
The lamp container is provided with a cooling pipe which is provided so as to penetrate in an airtight manner and through which a cooling medium flows.

[0009]

According to the above construction, the impurities produced by the etching action are deposited and deposited on the surface of the cooling pipe whose temperature is lower than that of the lamp container, so that the transparency of the lamp container is prevented from being lowered by the impurities. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The microwave discharge light source device of the present invention shown in FIG. 1 includes a microwave oscillator 1. One end of a waveguide 2 is connected to the microwave oscillator 1. The other end of the waveguide 2 is connected to the other end surface of a cylindrical microwave resonant cavity body 3 having an open one end surface. A power feed port 4 is formed at the connecting portion between the waveguide 2 and the microwave resonant cavity 3. A metal mesh 5 is provided as a member that allows light to pass therethrough and blocks microwaves on one end surface of the microwave resonant cavity body 3 that is open.

Therefore, the microwave oscillated and output from the microwave oscillator 1 is transmitted through the waveguide 2 and fed into the microwave resonant cavity 3 through the feed port 4.

A lamp container 6 is arranged inside the microwave resonant cavity 3. The lamp container 6 is made of a material having excellent heat resistance, for example, quartz glass, and is formed into a hollow spherical shape. A cooling pipe 7 is provided in the lamp vessel 6 so as to penetrate therethrough in the radial direction. The penetrating portion of the cooling pipe 7 is hermetically sealed by the welded portion 8 as shown in FIG.

As the cooling pipe 7, the lamp vessel 6 is used.
When quartz is quartz, the material having a coefficient of expansion close to that of the lamp vessel 6 and being easy to weld, for example, KOV (cover).
) Is preferably used, and as another material in place of KOV, a fluorine-based resin having excellent heat resistance or Pyrex glass may be used.

Both ends of the cooling pipe 7 project from the outer peripheral surface of the microwave resonant cavity 3, and both ends of the cooling pipe 7 are detachably interposed in the middle of the circulation pipe 9 via a connector 10.

A circulation pump 11 and a chiller 12 are connected to the circulation pipe 8. The circulation pipe 11 circulates a cooling medium such as water through the circulation pipe 8, and the chiller 12 circulates to cool the cooling medium whose temperature has risen.
Thereby, the cooling pipe 7 penetrating the lamp vessel 6 is cooled.

The lamp vessel 6 is filled with a discharge luminescent material. Helium (H
e), neon (Ne), krypton (Kr) and fluorine (F ₂ ) mixed gas, He, Ne, argon (Ar) and F ₂ mixed gas, He, Ne, and F ₂ mixed gas, Ne and A mixed gas of F _{2 or} the like is used, and light having different wavelengths in the ultraviolet region can be output according to each mixed component.

In the microwave discharge light source device having the above structure, when the microwave oscillator 1 is operated to output microwaves, the microwaves propagate through the waveguide 2 and the power supply port 4
Power is supplied to the microwave resonant cavity 3 from the inside. The microwave supplied to the microwave resonant cavity body 3 resonates inside the microwave resonant cavity body 3 to excite the discharge luminescent material in the lamp container 6.
As a result, the discharge luminescent material in the lamp vessel 6 emits light, and the light is output from the metal mesh 5 to the outside.

At the same time that the microwave oscillator 1 is operated, the circulation pump 11 is operated to circulate the cooling medium. As a result, the discharge luminescent material is excited by microwaves, so that even if the internal temperature of the lamp vessel 6 rises, the temperature of the cooling pipe 7 penetrating the lamp vessel 6 is sufficiently lower than that of the lamp vessel 6. Maintained at.

When the discharge luminescent material is activated by being excited, radicals and ions etch the inner surface of the lamp vessel 6, and the etching action produces impurities such as SiF ₄ . However, as shown in FIG.
Is attached and deposited on the surface of the cooling pipe 7 whose temperature is lower than that of the above.

Although the chemical basis of the impurities 20 adhering to and depositing on the surface of the cooling pipe 7 is unknown, the fact can be confirmed by experiments. That is, the conventional lamp vessel in which the cooling pipe 7 is not provided in the lamp vessel 6 and the lamp vessel 6 in accordance with the present invention in which the cooling pipe 7 is provided are used to transmit light from the lamp vessel 6 when used for 50 hours. The rate was measured.

As a result, in the conventional structure, the light transmittance is reduced by about 20%, but in the structure of the present invention, it is about 1-2%.
Only a slight decrease was seen. Moreover, it was also visually confirmed that the impurities 20 were attached to the surface of the cooling pipe 7.

That is, by depositing the impurities on the surface of the cooling pipe 7 whose temperature is lower than that of the lamp vessel 6,
It is possible to prevent the transparency of the lamp container 6 from being lowered and to maintain the light transmittance satisfactorily for a long time.

[0023]

As described above, according to the present invention, the lamp pipe accommodating the discharge luminescent material is provided with the cooling pipe through which the cooling medium flows in an airtight manner. Therefore, even when the discharge luminescent material is activated by being excited by microwaves and the impurities are generated by etching the inner surface of the lamp container, the impurities adhere to the surface of the cooling pipe whose temperature is lower than that of the lamp container. Since they can be deposited, it is possible to prevent the light transmittance of the lamp vessel from being lowered at an early stage.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a first embodiment of the present invention.

FIG. 2 is an enlarged view of a cooling pipe portion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Microwave oscillator, 2 ... Waveguide, 3 ... Microwave resonance cavity body, 4 ... Feed port, 6 ... Lamp container, 7 ... Cooling pipe, 9 ... Circulation pipe, 11 ... Circulation pump, 12 ... Chiller.

Claims (1)

[Claims] 1. A microwave oscillator for oscillating a microwave, a waveguide for guiding the microwave oscillated by the microwave oscillator, and a microwave resonant cavity body connected to the waveguide through a feed port. A lamp container provided in the microwave resonant cavity, in which a discharge luminescent substance that is excited by the microwave and discharges and emits light is contained;
A microwave discharge light emitting device, comprising: a cooling pipe, which is provided so as to penetrate through the lamp container in an airtight manner and through which a cooling medium flows.