JP3912171B2 - Light emitting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a visible and ultraviolet spot radiation source, and more particularly to an ultraviolet spot radiation source having a large output.
[0002]
[Prior art]
In the electronic industry field such as semiconductors and liquid crystals, ultraviolet exposure is performed for transfer exposure of a fine circuit pattern onto a semiconductor substrate or a liquid crystal substrate, and an ultraviolet light source having a point light source is used for the light source device.
In recent years, market demands for increasing the exposed area and increasing the throughput of production lines are increasing. At present, as an ultraviolet light source for large area exposure, a mercury lamp using light emission of mercury vapor is used. This is a discharge lamp in which a pair of refractory metal electrodes are arranged in a quartz glass bulb, and several mg to several tens mg / cc or more of mercury and a rare gas such as argon are enclosed in the bulb as a buffer gas. However, since it has electrodes, the output is limited to 10 kW. This is because the electrode on the anode side is heated and evaporates, and the discharge itself cannot be sustained due to the decrease in radiated light due to blackening in the bulb and the melting of the electrode.
[0003]
Plasma emission using a laser is also considered. However, this is not practical because the energy conversion efficiency of the laser is low. Further, although a microwave excitation light source has been studied as an electrodeless lamp, for example, it is difficult to make a point light source. The reason is as follows. Since the microwave has a long wavelength of 1 cm or more, it cannot be concentrated below the wavelength.
In addition, it cannot be converted into a point plasma.
[0004]
A visible light point light source is also desired to have a large output. For the purpose of weathering tests, xenon lamps are currently used for large area uniform irradiation of fibers and solar cells. However, the increase in output is limited to 7 kW. As a high-power visible light source, there is a light source called a vortex arc. However, this has a drawback in that electrode replacement is frequently required and maintenance is troublesome.
[0005]
Recently, the millimeter wave and submillimeter wave generators have dramatically improved the conversion efficiency of millimeter waves and submillimeter waves with respect to the input power. For example, a millimeter wave submillimeter wave generator called a gyrotron has a conversion efficiency of 50% from the input power. Has attracted attention. For example, Applied Physics Vol. 70, No. 3, 2001, pages 322 to 326, an example is shown. This document shows the basic configuration and operating principle. This millimeter wave submillimeter wave does not require a waveguide unlike microwaves, and can propagate power in the air. The inventor has intensively studied the application of the millimeter wave submillimeter wave generator to a point-like radiation source, and as a result, has reached the present invention.
[0006]
[Problem to be Solved by the Invention]
For the exposure of a large area as described above, an ultraviolet light source that is converted into a point light source to an output of about 15 kW or more and about 10 mm is desired. Further, a visible light source having a high output of 20 kW or more is desired for a light resistance test application. Accordingly, an object of the present invention is to realize a point light source capable of continuously emitting high-power light regardless of the life of the electrode.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention according to claim 1 is characterized in that an electromagnetic wave having a wavelength of 0.1 mm to 10 mm from a millimeter wave sub-millimeter wave generation source is once magnified by an electromagnetic wave magnifying reflector or an electromagnetic wave magnifying lens and then converged. Light radiation that converges with a reflecting mirror or electromagnetic wave converging lens, turns the gas sealed in an airtight container that transmits the converging electromagnetic wave and radiation near the convergence point into plasma, emits light, and collects the emitted light using a reflecting mirror A device,
An electromagnetic wave absorber that absorbs an electromagnetic wave having a wavelength of 0.1 mm to 10 mm and having a size comparable to the solid angle of convergence of the electromagnetic wave is provided on the side opposite to the electromagnetic wave introduction point with respect to the electromagnetic wave convergence point position. A light emitting device characterized by the above.
[0008]
According to a second aspect of the present invention, there is provided the light emitting device according to the first aspect, wherein the light emitting gas contains a rare gas as a main component.
[0009]
The invention described in claim 3 is characterized in that the light-emitting gas contains a metal selected from mercury, zinc, and indium, a metal halide, or sulfur. This is a light emitting device .
[0014]
The invention according to claim 4 converges the electromagnetic wave, according to any one of claims 1 to 3, characterized in that a starting auxiliary antenna in the vicinity of the region to be a gas discharge in the vicinity of its focal position This is a light emitting device.
[0015]
[Action]
According to the configuration of the present invention, the millimeter wave and the submillimeter wave, which have achieved conversion efficiency of 50% or more with respect to the input power, are once enlarged and then converged, converted into plasma at the focal position, emitted, and dotted. Becomes a radiation source. By providing the reflecting mirror, it is possible to collect light from the plasma in a small window and prevent leakage due to scattering of incident electromagnetic waves.
[0016]
When a rare gas is a main component as a light emitting gas, the rare gas can start to emit light with a low incident electromagnetic wave energy, so that starting is facilitated.
[0017]
Further, when another radioactive species is added in addition to the rare gas, radiation having a wavelength suitable for the application can be obtained. By containing the gas in the hermetic container, light emission at high atmospheric pressure is possible, and the radiation output can be increased.
[0019]
By providing the electromagnetic wave absorber on the side opposite to the electromagnetic wave introduction side with respect to the electromagnetic wave convergence point position, it is possible to prevent the electromagnetic wave from leaking outside the radiation device until the start of light emission.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the light emitting device of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment, in which a beam-like submillimeter wave with an output of 384 GHz and 10 kW is introduced from a millimeter wave submillimeter wave generation source 1 into a metal casing 100 to expand a metal electromagnetic wave having high conductivity. The submillimeter wave is temporarily magnified by the reflecting mirror 2, and the submillimeter wave is converged at a short focal point by the solid angle (θ1) of 0.6 steradian by the electromagnetic wave converging reflector 3.
[0023]
The convergence point s is located at the center of a glass container 10 made of, for example, quartz glass, and argon Ar about 10 kPa and mercury Hg 20 mg / cc are enclosed in the glass container 10 having a wall thickness of 3.5 mm and an outer diameter of 100 mm. The light source size is about 10 mm. Although not shown, the glass container 10 is used after forced air cooling.
[0024]
The glass container 10 is supported by a glass support bar 15. In the drawings of the present application, a support member that supports members other than the glass container 10 (for example, the electromagnetic wave magnifying reflector 2) is omitted for convenience.
[0025]
By providing the electromagnetic wave absorber 11 on the side opposite to the electromagnetic wave introduction side with respect to the electromagnetic wave convergence point s, it is possible to prevent the electromagnetic wave from leaking to the outside of the radiation device until the start of light emission. The electromagnetic wave absorber 11 is made of, for example, carbon black. The submillimeter wave is absorbed up to the stage where plasma is generated at the convergence point s. The electromagnetic wave absorber 11 may include a cooling mechanism (not shown).
[0026]
The light is reflected by the condenser reflector 4 and reaches the window 6 of the housing 5. Then, it passes through the window member 7 made of pure quartz glass, for example, and is emitted from the light emitting device 100 to the outside of the device. In addition to pure quartz glass, the window member 7 may be made of a material obtained by doping quartz glass with 20 ppm of TiO ₂ to absorb millimeter waves and submillimeter waves. The window member 7 may be a water cell.
[0027]
The light emission is equivalent to that of a conventional ultra-high pressure mercury lamp, and light emission is strong in the short wavelength region.
[0031]
Once the plasma is generated, the xenon atoms are excited and emit light. The appearing light source size is about 8 mm. The wavelength of light is a continuous spectrum from the ultraviolet to the visible range.
[0032]
In addition to xenon, helium He, neon Ne, argon Ar, and krypton Kr can be selected as the rare gas to be enclosed in the glass container 10, and further, metals such as mercury Hg, zinc Zn, indium In, metal halides, sulfur, etc. Luminescent species such as S can also be added. By doing so, radiation having a wavelength suitable for the application can be obtained. The emission spectrum is substantially the same as the emission spectrum of a conventional discharge lamp.
[0033]
FIG. 3 shows the configuration of a light emitting device as a second embodiment of the present invention. In this embodiment, an electromagnetic wave enlarging lens 41 and an electromagnetic wave converging lens 42 are used in place of the electromagnetic wave enlarging reflecting mirror 2 and the electromagnetic wave converging reflecting mirror 3, respectively. The electromagnetic wave magnifying lens 41 is made of, for example, silicon nitride or quartz, which absorbs less electromagnetic waves and has a high refractive index. The electromagnetic wave converging lens 42 is made of, for example, quartz.
[0034]
A millimeter wave of 41 GHz and 20 kW is introduced from the millimeter wave submillimeter wave generation source 1 into the metal casing 100, and the millimeter wave is temporarily magnified by the electromagnetic wave magnification lens 41, and the millimeter wave is 0.2 by the electromagnetic wave convergence lens 42. It is converged with a short focal point by the solid angle (θ3) of Stellarian. As the luminescent species sealed in the glass container 10, mercury Hg 23 mg / cc and 10 kPa argon Ar were used in the same manner as in the first example. The light source size is about 10 mm, and light emission is equivalent to that of a conventional ultra-high pressure mercury lamp, and light emission is strong in the short wavelength region.
[0035]
FIG. 4 shows the configuration of a light emitting device as a third embodiment of the present invention. In this embodiment, the electromagnetic wave enlarging reflecting mirror 2, the electromagnetic wave converging reflecting mirror 3, and the electromagnetic wave converging lens 42 are combined. Oite The difference from the first embodiment has the electromagnetic wave converging reflector 3 the first embodiment, whereas the aluminum, in the third embodiment, in that a gold-plated aluminum.
[0036]
A millimeter wave of 41 GHz and 20 kW is introduced from the millimeter wave / submillimeter wave generation source 1, the millimeter wave is once expanded by the electromagnetic wave magnifying reflector 2, and the millimeter wave is converged by the electromagnetic wave converging lens 42 with a short focal point. As the luminescent species sealed in the glass container 10, mercury Hg 23 mg / cc and 10 kPa argon Ar were used in the same manner as in the first example. The light source size is about 10 mm, and light emission is equivalent to that of a conventional ultra-high pressure mercury lamp, and light emission is strong in the short wavelength region.
[0037]
The window 6 from which light is extracted is provided with a rod integrator 8. By using the rod integrator, it is possible to shield the convergence of the utilized light and the electromagnetic wave from leaking out of the light emitting device 100.
[0040]
FIG. 7 shows a fourth embodiment having a starting auxiliary antenna 30. The starting auxiliary antenna 30 is covered with an insulator 50 except for the tip portion 30A. The starting auxiliary antenna 30 is connected to the high voltage unit 60. Compared with the case where there is no auxiliary antenna for start-up, plasma is generated from about 20% lower power, so that it is easy to start discharge, and the discharge start power range can be expanded to the low power side.
[0041]
A submillimeter wave of 384 GHz and 30 kW is introduced from the millimeter wave submillimeter wave generation source 1, the submillimeter wave is once magnified by the electromagnetic wave magnifying reflector 2, and the submillimeter wave is converged by the electromagnetic wave converging reflector 3 with a short focal point. The luminescent species sealed in the glass container 10 was xenon Xe1 MPa. The light source size that appears is about 8 mm. The wavelength of light is a continuous spectrum extending from the ultraviolet region to the visible region.
[0042]
In the above description of the present invention, an example in which a gyrotron is used as a millimeter wave submillimeter wave generation source has been described. However, there are a klystron, a barkator and the like in addition to the gyrotron.
[0043]
【The invention's effect】
According to the first aspect of the present invention, high-power UV and visible dot-like shapes can be obtained by a technique in which millimeter waves and sub-millimeter waves are converged, converted into plasma at the focal position, and emitted as a point-like radiation source. A light source can be realized. By providing the reflecting mirror, it is possible to collect light from the plasma in a small window and prevent leakage due to scattering of incident electromagnetic waves. And by accommodating gas in an airtight container, light emission at a high atmospheric pressure becomes possible and radiation output can be increased. By providing an electromagnetic wave absorber on the side opposite to the electromagnetic wave introduction side with respect to the electromagnetic wave convergence point position, it is possible to prevent the electromagnetic wave from leaking to the outside of the radiation device until the start of light emission.
[0044]
In particular, according to the second aspect of the present invention, when a rare gas is a main component as a light emitting gas, the rare gas can start to emit light with a low incident electromagnetic wave energy, so that starting is facilitated.
[0047]
According to the invention of claim 3 , another radiation species is added in addition to the rare gas, and radiation having a wavelength suitable for the application can be obtained.
[0050]
According to the invention of claim 4 , the discharge starting power can be widely obtained by providing the start assisting means.
[Brief description of the drawings]
FIG. 1 shows a first embodiment of a light emitting device of the present invention.
FIG. 2 shows an example of a light emitting device .
FIG. 3 shows a second embodiment of the light emitting device of the present invention.
FIG. 4 shows a third embodiment of the light emitting device of the present invention.
FIG. 5 shows an example of a light emitting device.
FIG. 6 shows an example of a light emitting device.
FIG. 7 shows a fourth embodiment of the light emitting apparatus of the present invention.

Claims (4)

An electromagnetic wave having a wavelength of 0.1 mm to 10 mm from a millimeter-wave sub-millimeter wave source is once magnified by an electromagnetic wave magnifying reflector or an electromagnetic wave magnifying lens, and then converged by an electromagnetic wave converging reflector or an electromagnetic wave converging lens, and converges near the convergence point. A gas emission device that converts a gas sealed in an airtight container that transmits radiated light into plasma, emits light, and collects the emitted light using a reflecting mirror,
An electromagnetic wave absorber that absorbs an electromagnetic wave having a wavelength of 0.1 mm to 10 mm and having a size comparable to the solid angle of convergence of the electromagnetic wave is provided on the side opposite to the electromagnetic wave introduction point with respect to the electromagnetic wave convergence point position. A light emitting device characterized by the above. The light emitting apparatus according to claim 1, wherein the gas that emits light contains a rare gas as a main component. 2. The light emitting device according to claim 1 , wherein the light emitting gas contains a metal selected from mercury, zinc, and indium, a metal halide, or sulfur. Electromagnetic waves converging light emitting device according to any one of claims 1 to 3, characterized in that a starting auxiliary antenna in the vicinity of the region to be a gas discharge in the vicinity of its focal position.

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