JPS6258565A - Microwave discharge device - Google Patents

Abstract

PURPOSE:To let discharge take place without any electrode, by placing a non- electrode discharge tube filled with a gas in a folded type wave guide with holes which are smaller than lambda/2 and provided at the maximum electric field portion and introducing a microwave in the wave guide. CONSTITUTION:A wave guide 1 is periodically folded and has a discharge tube 3 running through holes 2 provided in the center portions of the bulkheads of the wave guide. A strong electric field is applied to the discharge tube running through the center portions of the wave guide 1 and discharge takes place without any electrode. Besides, a microwave propagates as a progressive wave in the wave guide which has the folded structure and the discharge tube is placed at the strong electric field portion, so that the long discharge tube can make uniform radiant light emission.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microwave discharge device, and particularly to a mechanism for electrodelessly discharging a discharge tube that generates ultraviolet rays or the like using microwaves.

[Conventional technology]

Photoresists and certain types of paint used to form circuit patterns on semiconductors can be rapidly hardened or made insoluble by irradiation with ultraviolet light. Ultraviolet light is also widely used for purposes such as sterilization. A gas-filled discharge tube is generally used to generate this ultraviolet light.

In conventional discharge tubes, a gold/jl electrode is enclosed, and a voltage is applied to the electrode to generate a discharge. Therefore, it was not possible to apply a power higher than the withstand power of the electrode, and high output could not be obtained. Further, since corrosive gases such as halogens and halides cannot be filled in, the types of usable filled gases are limited, and there is also the problem that desired spectral components cannot be obtained.

[Problem that the invention seeks to solve]

The present invention focuses on the fact that various drawbacks of conventional discharge tubes are mainly caused by the enclosed metal electrodes, and provides a microwave discharge device in order to solve these problems with an electrodeless discharge tube. The purpose is to

[Means for solving problems]

In order to achieve the above object, the present invention inserts and installs an electrodeless discharge tube whose dielectric material is filled with gas into a folded waveguide having a hole with a size smaller than λ/2 at the maximum electric field. We propose a microwave discharge device that generates electric discharge without electrodes by introducing microwaves into this waveguide. However, λ is the wavelength of the microwave.

[Action of the invention]

FIG. 3 is a diagram showing the electric lines of force inside the waveguide and the electric field of the fundamental wave mode. As shown in the figure, the electric field of the fundamental wave mode of the waveguide 1 has the maximum intensity at the center of the cross section of the waveguide. If a dielectric is placed through the maximum part of this electric field, it can be heated strongly by the action of the electric field in that part.

If the waveguide 1 is bent as shown in FIG. 4, the discharge tube 3 is passed through the hole 2, and microwaves are introduced.

- the above effect becomes even more pronounced, the heated part being extended and practically continuous;

Incidentally, when a cavity resonator is used to generate microwave discharge, the discharge tends to be localized, and it is difficult to emit light from a point m in a long tubular discharge tube.

In the present invention, energy is added to the gas inside the discharge tube using a strong field to cause a discharge, so there is no need to encapsulate a metal electrode in the discharge tube.

[Embodiments of the invention]

Next, the present invention will be explained in detail with reference to FIGS. 1 and 2.

FIG. 1 is a longitudinal sectional view showing an embodiment of a microwave discharge device according to the present invention using a continuously folded waveguide based on the above principle. In FIG. 9, the waveguide 1 is It has a folded shape, and a discharge tube 3 is inserted through a hole 2 provided in the partition wall at the center.

FIG. 2 is a cross-sectional view of the microwave discharge device of FIG. 1. In the figure, 4 is a mesh structure portion with a pitch that allows light generated by discharge to pass through but prevents microwaves from leaking.

In this embodiment having such a structure, a strong electric field is applied to the discharge tube passing through the center of the waveguide, and it is possible to cause a discharge without an 'It pole. Moreover, in the folded waveguide structure, the microwave propagates as a traveling wave, and since the discharge tube is attached to the part where the electric field is strong, the long tubular discharge tube is uniformly discharged and emitted light. be able to.

Note that the diameter of the hole 2 provided in the gap (V) should be less than half the wavelength λ of the microwave so that the microwave does not directly leak through the hole into the adjacent waveguide.

Furthermore, by providing the mesh structure portions 4 on both sides of the waveguide 1 and placing a reflecting mirror with a suitable curved surface on the outside of one side, it becomes possible to condense and utilize light from both sides in a desired direction. .

〔Effect of the invention〕

In the present invention, a discharge tube whose dielectric material is filled with gas,
It is inserted into a folded waveguide having a hole smaller than λ/2 at the maximum electric field, and the microwave introduced into the folded waveguide generates a discharge, resulting in the following effects.

(1) Since it is an electrodeless discharge without inserting a gold FA electrode into the 11L discharge tube, the power resistance is increased and high output light can be extracted.

(2) By enclosing a corrosive gas such as halogen, it is possible to utilize spectrum 1 components that have not been available until now.

(3) It is easy to replace a discharge tube without electrodes.

(4) The mesh structure portion can efficiently extract light without leaking microwaves to the outside.

(5) By providing the W4RT structure on both sides of the waveguide and placing an appropriately curved reflective surface on the outside of one side, there is a possibility that the light from both sides of the waveguide can be focused and used in the desired direction. .

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the microwave discharge device δ according to the present invention using a continuous folded waveguide, FIG. 2 is a cross-sectional view of the embodiment shown in FIG. 1, and FIG. FIG. 4 is a diagram showing the electric lines of force inside the wave tube and the electric field of the fundamental wave mode, and FIG. 4 is a diagram showing a part of the folded waveguide.

Claims (2)

[Claims] (1) A folded waveguide with a hole smaller than λ/2 at the maximum electric field part, and a folded waveguide formed by filling a dielectric with gas and inserted into the hole at the maximum electric field part of the folded waveguide. What is claimed is: 1. A microwave discharge device comprising: a discharge tube; the microwave discharge device is characterized in that a discharge is generated by microwaves introduced into the folded waveguide; (2) The microwave discharge device according to claim 1, wherein a part of the side wall of the folded waveguide has a mesh structure that is transparent to light and does not allow microwaves to pass therethrough.