JPS63224193A - Light source device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light source device that can irradiate a flat surface with ultraviolet rays with high output.

[Conventional technology]

Examples of light source devices using microwaves include U.S. Patent 3,
No. 872,349 (Unitad 5tates P
agent.

In the above-mentioned conventional example, which is available in Japanese Patent No. 3,872,349), a cavity resonator is connected to a microwave power source, and a lamp is installed inside the cavity resonator. A standing wave of electromagnetic waves is generated within the cavity resonator, and when a lamp is installed at the peak of the standing wave, an induced discharge is generated within the lamp and light is emitted. An advantage of the device is that no electrodes are required in the lamp. Therefore, the structure of the lamp becomes extremely simple.

It also eliminates electrode wear and the release of impurities from the electrodes.

The life of the lamp is extended, and furthermore, there is no need to consider the reaction of the substance sealed in the lamp with the electrodes, which increases the degree of freedom in selection.

[Problem that the invention seeks to solve]

The shape of the lamp used in the above-mentioned conventional technology is straight tube or spherical, but it does not take into account uniform illumination of a flat surface.
Light sources are increasingly being used. Such special applications often require uniform illumination of a plane.

An object of the present invention is to obtain a light source device that can uniformly illuminate a plane.

[Means for solving the problem] The above purpose is to form a microwave cavity resonator into a flat plate shape,
A plurality of lamps are arranged in a plane inside the cavity resonator,
This can be achieved by turning on the lights at the same time.

[For production]

Inside the cavity resonator formed in the shape of a flat plate, it is possible to have multiple peaks of standing waves caused by electromagnetic waves, and by placing a lamp in the peaks, it is suitable for illuminating a flat surface. A light source can be obtained.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram showing a first embodiment of a light source device according to the present invention, FIG. 2 is a sectional view of a cavity resonator in the above embodiment,
FIG. 3 is an explanatory diagram of the size of the cavity resonator and the position of the lamp in the above embodiment, FIG. 4 is a diagram showing the cavity resonator of the second embodiment of the present invention, and FIG. FIG. 7 is a diagram showing a cavity resonator of a third embodiment.

FIG. 6 is a diagram showing a cavity resonator according to a fourth embodiment of the present invention, FIG. 7 is a diagram showing a cavity resonator according to a fifth embodiment capable of controlling the lamp temperature, and FIG. 8 is a diagram showing a cavity resonator according to a fifth embodiment of the present invention. FIG. 9 is a diagram showing a cavity resonator of the sixth embodiment, FIG. 9 is a diagram showing an eighth embodiment showing a method of supplying microwave power, FIG. FIG. 11 is a diagram showing the first embodiment of the present invention;
FIG. 12 is a diagram showing an eleventh embodiment of the present invention, (a) is a longitudinal sectional view, (b) is a horizontal sectional view, and FIG. 13 is a diagram showing the twelfth embodiment of the present invention. (a) is a longitudinal cross-sectional view,
(b) is a lateral sectional view, and 14th @ is a diagram showing a cavity resonator according to a 13th embodiment of the present invention.

In the first embodiment shown in FIG. 1, the lower surface of a rectangular parallelepiped cavity resonator 1 is formed with a mesh 3 so that light can be extracted. Further, a power supply port 4 is provided in the cavity resonator 1,
Microwave power is supplied from a power source 6 via a waveguide 5 . FIG. 2 is a cross-sectional view of the cavity resonator 1 taken along the line AA.

The lamp 2 is held by a fixture 7, and in order to attach or detach the lamp 2, the net 3 covering the lower surface of the cavity resonator 1 is fastened with screws 8 or the like and can be removed. The lamp exchange port is not limited to the part of the net 3, but only if the other part is removable.The cavity resonator 1 and the net 3 are both made of metal,
The lamp is preferably made of brass, copper, aluminum, etc. from the viewpoint of workability.The inner surface of the cavity resonator 1 has good electrical conductivity and is preferably silver plated to serve as a light reflecting plate. Reference numeral 2 denotes a hermetically sealed glass tube, in which various gases, metals, and their compounds as shown below are sealed. Microwaves introduced into the cavity resonator 1 through the power supply port 4 induce a discharge in the lamp 2, and the gas or metal is excited to emit light. The substance sealed in the lamp 2 varies depending on the purpose. For example, when using visible light, Hg, Na, T
Q, In, Sc, Th, Sn, or their halides and a rare gas of several tens of Torr are sealed. Also,
When using ultraviolet rays, use a material for the lamp 2 that has good UV transmittance, such as quartz, sapphire, CaF21MgF', or LiF, but it is especially recommended to use quartz, which has few metal impurities, in terms of workability and other aspects. Suitable from

The inclusions include Hg, Zn, Cd, Ss, As, or their halides, and rare gases or I2, H2,
Di (deuterium), Xs, etc. are suitable. The length of the lamp 2 varies depending on the purpose and the cavity resonator 1, and in the case of a straight tube type, the tube diameter is about 0.5 to 33 mm.

The power source 6 generates microwaves (electromagnetic waves with wavelengths from 1 to 1). The power of the microwave mentioned above varies depending on the application, but
The power is from several hundred W to several kW. Frequency 2.45 for practical degrees
It is appropriate to use a magnetron that emits GHz (wavelength 12.24 cm).

FIG. 3 is a diagram illustrating the size of the cavity resonator 1 and the position of the lamp 2. The cavity resonator 1 has lengths a, b, and c on each side.
In the case of a rectangular parallelepiped, the following equation (1) holds between the wave numbers Q, m, and n of the standing waves standing on each side in the cavity resonator 1.

(Q/a)”+ (m/b)”+ (n/c)”= (
2/λ0)" -...-(1) λ is the resonant wavelength. In Fig. 3, the broken line 9 indicates the standing wave. For example, in Figure 3, there are four waves on side a, and one lamp 2 is placed at the crest of each wave. The number of lamps 2 placed on each pile is not limited to one; several thin lamps may be placed near each pile. Note that the power supply port 4 shown in FIG. , provided at one position in the mountain.

With the above configuration, a plurality of lamps can be lit at the same time, and a light source device suitable for flat irradiation can be obtained.

The shape of the lamp 2 does not have to be a straight tube as shown in the first embodiment, and a plurality of spherical lamps 2' may be used as in the second embodiment shown in FIG. The diameter is 0.
It is about 5 to 4 am.

The shape of the cavity resonator 1 is not limited to a rectangular parallelepiped. The third embodiment shown in FIG. If the shape of the vessel is not simple, it will be impossible to calculate how the standing waves will form, but the positions of the lamp 2 and power supply port 4 can be determined by trial and error.

The fourth embodiment shown in FIG.
In this example, the arrow indicates the gas flow.

There are two purposes for flowing gas. One is cooling the lamp 2. The luminous efficiency of the lamp depends on the vapor pressure of the fill. Therefore, the vapor pressure of the substance enclosed within the lamp 2 can be controlled by the gas flow, and the luminous efficiency can be improved. the other one
One is the replacement of gas within the cavity resonator 1. When using the ultraviolet light emitted from the lamp 2, it is necessary to prevent absorption of the ultraviolet light by oxygen contained in the air. For this purpose, it is necessary to fill the inside of the cavity resonator 1 with nitrogen or rare gas. In this case, in order to maintain airtightness of the cavity resonator 1 to some extent, a quartz plate 12 is attached to the outside or inside of the mesh 3 provided in the cavity resonator 1 via a packing 11 or the like.

Next, let's talk about lamp efficiency. The efficiency of the lamp changes depending on the temperature, and the optimal temperature differs depending on the type of filling material. Maximum efficiency can be maintained by keeping the temperature between 30 and 60°C. In addition, when Cd or Zn is sealed, the temperature inside the cavity resonator 1 is set to 200-300℃ and 300-4℃, respectively.
If kept at 00°C, strong ultraviolet rays can be obtained. When the temperature inside the cavity resonator 1 becomes lower than the above optimum temperature,
Heat it by increasing the power or by providing an external heating means. Further, when the temperature inside the cavity resonator 1 becomes higher than the above-mentioned optimum temperature, the following embodiment is adopted.

In the fifth embodiment shown in FIG. 7, a hole having a diameter smaller than the cutoff wavelength of the microwave is formed in the cavity resonator 1.

A branch pipe 13 provided in the lamp 2 is brought out from the cavity resonator 1 through the hole. The fill in the lamp 2 collects in the coldest part of the lamp 2, and the temperature here determines the vapor pressure. Therefore, if the temperature of the branch pipe 13 is controlled to an optimum value, high efficiency can be maintained. Further, when metal or its halide is sealed, there is a problem that these adhere to the inner surface of the lamp 2 and prevent light from being extracted.

The above-mentioned problem can also be solved by a method in which a part of the lamp 2 is taken out of the cavity resonator 1 and the enclosed material is collected in the outside part.

If a part of the lamp 2 is to be taken out, the branch pipe 13 should not be provided.For example, if the lamp 2 is a straight pipe, the length should be made longer, and one end should be made with a hole in the side of the cavity resonator 1. Even if you open it and take it out...
good.

Furthermore, if several different types of lamps are placed inside the cavity resonator 1, it is possible to simultaneously irradiate wavelengths that are convenient for the purpose.For example, a lamp filled with Hg and a lamp filled with Cd
When the Hg-filled lamps are arranged alternately, the Hg bright line 253
It is possible to simultaneously irradiate 7 people with ultraviolet rays and 2,288 Cd emission lines. In the above case as well, since each lamp has a different optimum temperature, it is preferable to take a part of the lamp out of the cavity resonator 1 and control the temperature separately as described above.

Next, the size of the cavity resonator 1 will be explained.

For example, in semiconductor manufacturing processes, strong ultraviolet illuminance is often required.In order to increase the illuminance,
It is necessary to keep the distance between the lamp and the irradiation surface as close as possible. For this reason, the lamp 2 and the net 3 must be brought as close together as possible within the cavity resonator 1. To achieve this, the cavity resonator 1 must be made thin so that standing waves are not generated in the depth direction. From equation (1), b x λ should be made so that it does not stand. /2
If this happens, standing waves will not be able to stand on one side.

Therefore, even if the lamp 2 is moved in the b direction, the brightness of the lamp 2 does not change, and therefore the lamp 2 can be placed on the net 3. The sixth embodiment in this state is shown in FIG. 8. For example, one frequency is 2.45 GHz (wavelength λ, =
When using a magnetron of 12.24as) as a power source, the design should be such that b<6.12ai.If the lamp 2 cannot be directly supported by the net 3 as shown in Fig. 8, both ends of the lamp 2 should be It is sufficient to support the lamps and place a spacer or the like between the lamps to fix the lamps.

In addition, in order to improve the uniformity of light, two or more standing wave modes may coexist in the cavity resonator 1. As the peaks and troughs of the standing waves overlap, the electric field becomes uniform, and the light emission from the lamp becomes even more uniform.For example, in the rectangular parallelepiped cavity resonator 1 shown in FIG. m= on the two sides of
When the mode of (Q, n) and the mode of (ril, n') coexist at o, a, c become 0 according to equation (1).For example, m=1. In order for n=2, m=2, and n=1 modes to coexist, a = c = J from equations (2) and (3).
5/4 λ. If we use a magnetron as the power source and set the frequency to 2.4 GHz, then a=c to 13.
It will be 73. Therefore, in order to coexist a plurality of modes with a larger number of standing waves, a≧mλ. , C≧50,000λ.

Requires.

In order to further improve the uniformity, the number of standing waves standing on one side should be two or more. In other words, if the smaller of Ω and n is written as Min(Q, n), it is sufficient to set Min(a, n)≧2. From equations (2) and (3), to satisfy this, The two sides of the rectangular parallelepiped are at least ffλ. For example, n=2, n=3 (m=o
) and n=3゜n=2 to coexist, a = c
= “■Shoulder stiffness.

λ. =12.243 then a=c=
It becomes 22.1Qm. Also, m=3, n=4 and m=4,
To coexist with n=3, a=c=r Ti'ffλ.

, λ, = 12.240m, then a = c = 30.
For example, when using the above light source device to irradiate a silicon wafer with a diameter of 15 to 20 dl, the suitable size of the cavity resonator is a flat plate with a size of 20 to 30 cm. It is appropriate to use this mode.

These dimensions include errors equivalent to variations in the microwave oscillation frequency.

Next, a method of supplying microwave power will be explained. Figure 9 shows a coaxial cable 14 and a probe 15 connected to the cavity resonator 1.
It is a figure which shows the 8th Example which supplies electric power using.

The probe 15 may be of a loop type, the tip of which is connected to the cavity resonator 1.Using the coaxial cable 14 has the advantage that the cavity resonator 1 can be easily moved, unlike a waveguide. Also.

Adjustment is easier if the length of the probe 15 is variable. In Figure 10, the power source is a magnetron 18 and a high voltage source 16.
It is a figure which shows the 9th Example separated into. Since the magnetron 18 is small, the cavity resonator 1 can be moved together with the magnetron 18 by attaching it to the cavity resonator 1 via the waveguide 5 and supplying power from the high voltage source 16 via the high voltage cable 17. becomes easier. FIG. 11 is a diagram showing a tenth embodiment in which power can be supplied to two locations of the cavity resonator 1 via a coaxial cable 14 via a changeover switch 19. When the power supply locations are alternately switched at high speed, different standing wave modes are generated alternately according to each location, thereby improving the uniformity of the light source.

Next, the microwave power supply port will be explained. If the power loss caused by the lamp is large, the lamp output will be weak at a location far from the power supply port. In order to prevent this, the power supply port may be provided at the center of the widest surface of the cavity resonator.

FIG. 12 shows an eleventh embodiment showing this state, and (a) is a longitudinal cross-sectional view showing the cavity resonator 1 and the waveguide 5;
b) is a cross-sectional view. In this embodiment, a hole 20 is formed in the cavity resonator 1 and the waveguide 5, and an antenna 22 is inserted into the hole 20 via an insulator 21.

The insulator 21 is made of Teflon, silicone rubber, ceramic, etc., the antenna 22 is made of metal, and the insulator 21 and antenna 22 have threads, etc.
The above antenna 22 only needs to move up and down.The antenna 22 should be positioned at a position where the respective electric fields in the cavity resonator 1 and the waveguide 5 are maximum.For example, the microwave frequency is 2.4.
5GHz (at wavelength 12.24(!l).

The sides of cavity resonator 1 are a=103, b=23.201.
When Q = 4aa, there are 3 peaks of electric field standing waves on one side a.
, one will appear in b. In this case, the antenna 22 is located at the center of the rectangle with sides a and b. Further, when a is set to −19,4>, a mode in which there are three standing wave crests on one side a and one on each side coexists, and the opposite mode coexists, resulting in a more uniform lamp output. In this case side a
, b, and the antenna 22 is erected at the center of the rectangular parallelepiped. Also, a
= b = 35.7 am, there will be three or five crests of standing waves on each side, and the opposite modes will coexist, and in this case as well, the antenna 22 will be located at the center of the widest surface of the rectangular parallelepiped. In general, the antenna 22 is located in a circle concentric with the center of the widest surface consisting of side a and side C, so that standing waves do not appear on the shortest side of a rectangular parallelepiped cavity resonator. Its radius is within the node of a standing wave (the point where the electric field becomes O) of one or multiple coexisting modes.

Just place it in a circle that is the distance to the one closest to the center.

The electric field is supplied to the cavity resonator by using the hole 2 as shown in FIG. 13 instead of using the antenna as in the eleventh embodiment.
The position of the hole 20 is such that the directions of the magnetic fields in the waveguide 5 and the cavity resonator 1 are almost the same, and the hole 20 is located at the center of the rectangle formed by sides a and c. As a guideline for strong coupling, the angle between the magnetic field vectors of the waveguide 5 in the hole 20 and the magnetic field vectors in the cavity resonator 1 should be 45° or less.

The twelfth embodiment shown in FIG. 14 is an example in which the resonance frequency of the cavity resonator 1 can be adjusted.
By providing a plurality of screw holes 23 in the cavity resonator 1 and changing the length of the adjustment screw 24 in the cavity resonator 1 through the adjustment screw 24 inserted into the screw hole 23, the resonant frequency and standing wave mode can be adjusted. Can be adjusted.

Of course, the length of the adjustment screw 24 does not have to be a screw as described above, as long as it can be adjusted arbitrarily.

Furthermore, if the lamp is difficult to start in each of the above embodiments, a Tesla coil may be provided near the lamp to assist in starting the lamp.

〔Effect of the invention〕

As described above, the light source device according to the present invention includes a microwave power source, a cavity resonator connected to the microwave power source, and a lamp provided in the cavity resonator. By forming a part of the body resonator in a net shape and installing multiple lamps, the electrodeless lamp can emit light uniformly in a plane, so the lamp structure is simple and there is no impurity caused by the electrodes. A light source device suitable for planar irradiation can be obtained without any limitations.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a first embodiment of the light source device of the present invention;
Figure 2 is a sectional view of the cavity resonator in the above embodiment, and Figure 3 is a cross-sectional view of the cavity resonator in the above embodiment.
The figure is an explanatory diagram of the size of the cavity resonator and the position of the lamp in the above embodiment, FIG. 4 is a diagram showing the cavity resonator of the second embodiment of the present invention, and FIG. FIG. 3 is a diagram showing a cavity resonator of an example. FIG. 6 is a diagram showing a cavity resonator according to a fourth embodiment of the present invention, FIG. 7 is a diagram showing a cavity resonator according to a fifth embodiment capable of controlling the lamp temperature, and FIG. 8 is a diagram showing a cavity resonator according to a fifth embodiment of the present invention. A diagram showing the cavity resonator of the sixth embodiment, FIG. 9 is a diagram showing the eighth embodiment showing a method of supplying microwave type force, and FIG. 1O is a configuration diagram showing the ninth embodiment of the present invention. FIG. 11 is a diagram showing a tenth embodiment of the present invention,
FIG. 12 is a diagram showing an eleventh embodiment of the present invention, (a) is a longitudinal sectional view, (b) is a horizontal sectional view, and FIG. 13 is a diagram showing the twelfth embodiment of the present invention. (a) is a longitudinal cross-sectional view,
(b) is a lateral sectional view, and FIG. 14 is a diagram showing a cavity resonator according to a thirteenth embodiment of the present invention.

Claims (1)

[Claims] 1. A light source device comprising a microwave power source, a cavity resonator connected to the microwave power source, and a lamp provided in the cavity resonator, wherein the cavity resonator A light source device characterized in that a part of the lamp is formed into a net shape and a plurality of lamps are provided. 2. The light source device according to claim 1, wherein the cavity resonator is characterized in that one side of the rectangular parallelepiped forming the cavity resonator is smaller than half of the resonance frequency λ_0. . 3. The cavity resonator has at least two sides of the rectangular parallelepiped forming the cavity resonator, each having a resonance frequency λ_0 of √(
5/4) The light source device according to claim 1, wherein the light source is λ_0 or more. 4. The cavity resonator has at least two sides of the rectangular parallelepiped forming the cavity resonator, each having a resonance frequency λ_0 of √(
13/4) is greater than or equal to λ_0, and the other side is 1/2λ_0
The light source device according to claim 1, which is smaller and has a net shape on one of the widest surfaces of the rectangular parallelepiped.