KR100620539B1 - A gas laser device using a microwave - Google Patents

Abstract

The present invention relates to a gas laser apparatus using microwaves that generate a laser by exciting a gas using a plurality of inexpensive magnetrons. To this end, a plurality of magnetrons 70 for generating microwaves; A plurality of magnetron loungers 73 having one end connected to each magnetron 70 to transmit microwaves and a slot 77 formed at the other end; One end is sealed with a quartz glass 76 to be fitted with a plurality of slots 77, the gas 50, which is a medium therein, is sealed, and a total reflection mirror 60 is attached to one end and a semi-transparent mirror 33 at the other end. ), A focusing lens 35 and an optical fiber 30 provided on the rear surface of the cylindrical discharge tube 55 and the transflective mirror 33 are attached.

Laser, gas, excitation, lounger, magnetron, microwave, echo, slot, quartz

Description

A gas laser device using a microwave}

1 is a block diagram of a typical typical microwave application device,

2 is a perspective view of a lounger 73 used in the present invention;

3 is a cross-sectional view of a gas laser device using a microwave according to the present invention,

4 is an explanatory diagram showing a process of transitioning from a high level state to a medium level by being excited by a injected microwave gas, which is a sealed laser medium.

<Description of the symbols for the main parts of the drawings>

10: magnetron, 12: waveguide matcher,

14: directional coupler, 16: circulator,

18: applicator (plasma device or induction heating device)

20: power monitor, 30: optical fiber,

31: connection port, 33: transflective mirror,

35: focusing lens, 40: water-cooled jacat,

41: cooling water inlet, 43: cooling water,

45: cooling water outlet, 50: gas (CO ₂ ),

53: dielectric, 55: cylindrical discharge tube,

60: total reflection mirror, 61: mirror fixing axis,

63: tilt adjusting screw, 65: diaphragm,

73: magnetron lounger, 75: stage

76: quartz glass, 77: slot.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser apparatus using microwaves, and more particularly, to a gas laser apparatus using microwaves to generate a laser by exciting a gas using a plurality of magnetrons.

Generally, a medium of a laser is classified into a gas, a liquid, a solid, and a semiconductor having a density reversal function, and is classified into discharge excitation, electron light excitation, photo excitation, chemical reaction excitation, and current excitation according to the excitation method.

Especially in the case of gas lasers, most atoms or molecules have a high energy level when a gas, which is a medium, is injected into the resonator and properly excited by electric discharge. Excited molecules or atoms return to low levels at a time under certain conditions, emitting light corresponding to their energy difference. At this time, the emitted light has a unique wavelength having a uniform phase of a single wavelength. For example, when carbon dioxide is used as a medium, the wavelength is 9 µm to 11 µm. CO, HF, I ₂ , He-Ne, He-Cd, Cu steam, Au steam, Ar ion, Kr ion, N ₂ , F ₂ , XeF, XeCl, KrF, KrCl, ArF, Xe ₂ , Kr ₂ And gases such as Ar ₂ are used.

In the case of such a gas laser, a direct current discharge method for applying a direct current high voltage to both ends of the discharge electrode, an inductive coupling method for applying a high frequency current to a coil installed outside the dielectric filled with the laser medium gas, and a laser between the capacitive discharge electrodes There is a capacitive coupling method of encapsulating medium gas.

Since the amount of laser generation is proportional to the excitation power, the dielectric constant of the gas changes rapidly when ionization starts, so it is very important to stabilize the discharge current. Therefore, the price portion of the power supply in the laser generator is very large.

Microwave oscillation elements include magnetrons, klystrons, traveling waveguides, etc., but magnetrons in the 2.45 GHz band used in home appliances are easy to obtain and inexpensive. Since the transmission of microwaves is omnidirectional radiation through free space, the waveguide is mainly used for transmission to a specific section and is resonated in a volume of cavity. The transmission impedance and the length of the wavelength are determined by the opening surface of the waveguide, and the impedance matching between the lines is a very important factor for transmitting microwaves. Reflected waves are generated when the impedances between the lines do not match or do not resonate with the applicator. These reflected waves cause a decrease in efficiency, and return to the generator to shorten the life or cause a failure.

1 is a block diagram of a typical typical microwave application. As shown in FIG. 1, the microwave energy radiated from the magnetron 10 is passed through a directional coupler 14 and a circulator 16 connected to a power monitor 20 via a waveguide matcher 12 and an applicator 18. Is applied.

The stub tuner 12 is configured to adjust the line impedance of the waveguide so as to be optimal with the applicator.

The directional coupler 14 is a device that extracts only a predetermined ratio of microwaves transmitted in the waveguide at a predetermined rate, and is a kind of monitoring device.

The circulator 16 delivers electromagnetic waves transmitted from the magnetron to the applicator and transmits the reflected power to the other port, and is usually configured to convert it into heat in a dummy load.

The applicator 18 is a generic term including a plasma device, an induction heating device, or the like.

Typically, for a CO ₂ laser with an efficiency of about 20%, applying 1 KW of continuous wave power yields an energy of 50 mJ / sec. When used in a pulse mode with a duty ratio of 500: 1, an energy of 25 J / pulse is obtained. If you want to get more power, you can use a high power magnetron, but the price is very expensive, which increases the economic burden.

Accordingly, the present invention has been made in view of the above-described conventional problems, and a first object of the present invention is to provide a gas laser apparatus using microwaves which can excite a gas laser using a plurality of inexpensive magnetrons.

The second object of the present invention is to add a resonator of TE011 mode, which also serves as a lounger, to each of the magnetrons to operate as a shock absorber for impedance change, and to perform the impedance conversion process by the slot and the shear wave mode in the process of entering the laser generating tube. It is to provide a gas laser device using a microwave that can minimize the reflected wave through the process of converting the into a circular polarization.

The third object of the present invention is to present a structure of a discharge tube encapsulation, a structure of a resonator, a cooling method, and the like, and by controlling the power applied to a plurality of magnetrons individually, a gas laser device using microwaves that can control the output of the laser To provide.

An object of the present invention as described above, the plurality of magnetrons 70 for generating a microwave;

A plurality of magnetron loungers 73 having one end connected to each magnetron 70 to transmit microwaves and a slot 77 formed at the other end;

One end is sealed with a quartz glass 76 to be fitted with a plurality of slots 77, the gas 50, which is a medium therein, is sealed, and a total reflection mirror 60 is attached to one end and a semi-transparent mirror 33 at the other end. Cylinder discharge tube 55 is attached; And

It comprises a focusing lens 35 and the optical fiber 30 installed on the back of the transflective mirror 33;
In the inner diameter of the discharge tube 55, a dielectric material 53 having a higher dielectric constant than air is further formed in a hollow shape, and the gas 50 may be achieved by a gas laser apparatus using microwaves. Can be.

In addition, it is more preferable that two to four magnetrons 70 and magnetron loungers 73 are disposed radially.

In addition, a circumference of the cylindrical discharge tube 55 may be further provided with cooling means, the cooling means comprising: a cylindrical water cooling jacket 40 surrounding the circumference of the cylindrical discharge tube 55;

Cooling water inlet 41 formed in the lower portion of the water cooling jacket 40;

Cooling water outlet 45 formed on the top of the water cooling jacket 40; And

Cooling fan 80 formed in the lower portion of the discharge tube 55;

On the other hand, the length of the magnetron lounger 73 is equal to the length of one wavelength for the microwave of 2.5GHz,

In order to cancel the reflected wave, it is most preferable that the stage 75 is further formed in the 1/2 wavelength length region in the longitudinal direction.

In addition, the magnetron lounger 73 may be primarily resonated in the TE012, TE013, or TE014 mode, and the slot 77 may have a length of 3/4 of the waveguide width and a width of 6 mm to 10 mm.

Gases of the gas laser according to the present invention is CO ₂ , CO, HF, I ₂ , He-Ne, He-Cd, Cu steam, Au steam, Ar ions, Kr ions, N ₂ , F ₂ , XeF, XeCl, KrF , KrCl, ArF, Xe ₂ , Kr ₂ , Ar ₂ or a plurality of mixtures or compounds.

Other objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings.

Hereinafter, a configuration of a gas laser apparatus using a microwave according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a perspective view of the lounger 73 used in the present invention. As shown in FIG. 2, the length of the magnetron lounger 73 is equal to the length of one wavelength for the microwave of 2.5 GHz, and the stage 75 in the half wavelength length region in the longitudinal direction to cancel the reflected wave. Is formed. For this reason, the phases of the reflected waves generated in the slot 77 region and the reflected waves generated in the stage 75 region are offset by 180 degrees. This is to protect the magnetron 70 from the reflected wave.

A magnetron 70 is connected to one end of the magnetron lounger 73, and a slot 77 is formed at the other end, and the slot 77 corresponds to the quartz glass 76 below the discharge tube 55 described later. Is fixed as possible. The slot 77 is suitably in length ranging from 3/4 of the waveguide width and 6 mm to 10 mm in width, particularly 8 mm.

3 is a cross-sectional view of a gas laser device using microwaves in accordance with the present invention. As shown in FIG. 3, a water cooler cat 40 is provided around the cylindrical discharge tube 55, and a semi-transparent mirror 33, a connection port 31, and an optical fiber 30 are provided at an upper end thereof. At the bottom, quartz glass 76, total reflection mirror 60, and the like are provided. In addition, a plurality of magnetron loungers 73, respective magnetrons 70, and cooling fans 80 are provided below the discharge tube 55.

The cylindrical discharge tube 55 is cylindrical in shape, and a dielectric 53 is sandwiched therein. The dielectric 53 is made of a material having a dielectric constant higher than 1.00004 of air (for example, quartz, alumina, nitrogen boride, etc.), and the dielectric constant is higher than air, thereby reducing the diameter of the discharge tube 55 necessary for resonance. It works. This dielectric 53 is hollow, and inside the gas (carbon dioxide in this embodiment) is sealed in the axial direction. The volume of the discharge tube 55 is determined so as to have a condition capable of resonating in the TM012, TM013, TM014, and TM015 modes in the state where the dielectric 53 is inserted.

The semi-transmissive mirror 33 functions to seal the upper center of the discharge tube 55, reflect a part of the excited light, and transmit the remaining part. A focusing lens 35 is provided on the rear surface of the transflective mirror 33 along the traveling direction of light, and an optical fiber 30 is provided on the rear surface of the focusing lens 35. The semi-transparent mirror 33, the focusing lens 35 and the optical fiber 30, etc. are firmly fixed by the connection port 31.

The water cooler cat 40 surrounds the circumference of the discharge tube 55, and is provided with a coolant inlet 41 at the lower end and a coolant (outlet 45) at the upper end. After entering through 41, the heat exchanger rises and exits to the coolant outlet 45. In addition, since the cooling fan 80 is provided at the lower portion of the magnetron lounger 73, the water cooler cat 40 is rotated. Cooling can be promoted.

The total reflection mirror 60 is located at the lower center of the discharge tube 55, and the rear surface of the mirror fixing shaft 61 that can finely adjust the total reflection mirror 60 is formed. Therefore, the total reflection mirror 60 moves together according to the movement of the mirror fixing shaft 61.

The diaphragm 65 is formed at any point on the axis of the mirror fixing shaft 61, and accommodates the minute movement of the mirror fixing shaft 61, while simultaneously performing the sealing action of the gas.

The tilt adjustment screw 63 is finely conveyed in the axial direction according to the left and right rotation, and is configured to tilt the mirror fixing shaft 61 by using this movement. To this end, the tilt adjustment screw 63 is provided with three to four around the mirror fixing shaft 61, it is configured to transmit the tilt to the mirror fixing shaft 61 by the arm (not numbered). Using such a tilt adjustment screw 63, the semi-transmissive mirror 33 and the total reflection mirror 60 can be fixed in position to be completely parallel on the same axis.

The quartz glass 76 is uniformly arranged on the circumference of the lower end of the discharge tube 55. Since this corresponds to one-to-one correspondence with the slot 77 described below, the number should be the same as the slot 77. In this embodiment, three quartz glass 76 are provided.

3 to 4 magnetron loungers 73 are disposed at equal angles in the radial direction around the discharge tube 55. In this example, three were arranged. At this time, the slot 77 of the lounger 73 is positioned to coincide with the quartz glass 55 at the lower end of the discharge tube 55.

The magnetron 70 generating microwaves is fixed to one end of the lounger 73, and a cooling fan 80 is rotatably installed at one side of the magnetron 70.

Hereinafter, the operation of the gas laser device using the microwave having the configuration as described above will be described in detail.

First, power is supplied to the magnetron 70 that emits microwaves at 2.45 GHz to emit microwaves. The emitted microwave is first resonated in the TE012, TE013, and TE014 modes while passing through the lounger 73, and the reflected wave is removed and then transmitted to the quartz glass 76 through the slot 77.

The microwaves in the discharge tube 55 excite the gas 50 while being resonated by the dielectric 53. 4 is an explanatory diagram showing a process of transitioning from a high level state to a medium level by being excited by a injected microwave gas, which is a sealed laser medium. As shown in FIG. 4, the gas excited to a high level by the energy of the microwave stays in a high level state, transitions to a medium level state under certain conditions, and emits light having a specific wavelength in this process. As a result, excited gases in other mid-levels also transition to the ground state after inducing and emitting light.

The light generated in this process is reciprocated between the total reflection mirror 60 and the transflective mirror 33, and when exceeded a certain threshold, is emitted as a laser through the transflective mirror 33. The emitted laser is collected by the focusing lens 35 and transported along the optical fiber 30.

In the present invention, by using a plurality of magnetrons 70, when the power is applied only to some of the magnetrons 70, the output of the laser can be proportionally reduced. In addition, when intermittently interrupting the applied high voltage, a pulse wave laser may be implemented.

The gas of the gas laser according to the present invention is not only CO ₂ but also CO, HF, I ₂ , He-Ne, He-Cd, Cu vapor, Au vapor, Ar ions, Kr ions, N ₂ , F ₂ , XeF, XeCl, It can be used for almost any gas laser, such as any one or a plurality of mixtures or compounds of KrF, KrCl, ArF, Xe ₂ , Kr ₂ , Ar ₂ .

As described above, according to the gas laser device using the microwave according to the present invention, since it is possible to excite the gas laser using a plurality of extremely low-cost magnetrons without numerous transistors and FETs, it is economical and easy to implement.

And, by adding a resonator of TE011 mode, which also serves as a lounger, to each magnetron, it acts as a shock absorber for impedance change, and the impedance conversion process by slot and transverse wave mode is converted into circular polarization in the process of entering the laser generator tube. By minimizing the reflected wave through the process, high quality laser can be obtained.

In addition, the structure of the discharge tube encapsulation, the structure of the resonator, the cooling method, and the like are presented, and by individually controlling the power applied to the plurality of magnetrons, it is possible to finely control the output of the laser. This can be a great help to expand the scope of use of this laser.

Although the invention has been described in connection with the preferred embodiments mentioned above, other various modifications and variations may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the appended claims cover such modifications and variations as fall within the true scope of the invention.

Claims (8)

A plurality of magnetrons 70 for generating microwaves; A plurality of magnetron loungers 73 having one end connected to each of the magnetrons 70 to transmit microwaves and a slot 77 formed at the other end thereof; One end is sealed with a quartz glass 76 to fit with the plurality of slots 77, the gas 50 is a medium therein, a total reflection mirror 60 is attached to one end, and a semi-transparent mirror at the other end ( A cylindrical discharge tube 55 to which 33 is attached; And It comprises a focusing lens 35 and the optical fiber 30 installed on the back of the transflective mirror (33); In the inner diameter of the discharge tube (55), a dielectric (53) having a higher dielectric constant than air is further formed in a hollow shape, and the gas (50) is a gas laser device using a microwave, characterized in that the hollow shape. delete [2] The gas laser device of claim 1, wherein two magnetrons and four magnetron loungers are disposed radially. The gas laser device using microwaves according to claim 1, wherein cooling means is further provided around the cylindrical discharge tube (55). The method of claim 4, wherein the cooling means, A cylindrical water cooling jacket 40 surrounding the circumference of the cylindrical discharge tube 55; Cooling water inlet 41 formed in the lower portion of the water cooling jacket 40; Cooling water outlet 45 formed on the water cooling jacket 40; And Gas laser device using a microwave, characterized in that consisting of; cooling fan (80) formed in the lower portion of the discharge tube (55). The length of the magnetron lounger 73 is equal to the length of one wavelength for microwave of 2.5 GHz, The gas laser device using a microwave, characterized in that the stage (75) is further formed in the half-wavelength region in the longitudinal direction to cancel the reflected wave. 7. The gas laser device of claim 6, wherein the magnetron lounger (73) is first resonant in TE012, TE013, or TE014 mode. The gas laser device according to claim 1, wherein the slot (77) has a length of 3/4 of the waveguide width and a width of 6 mm to 10 mm.

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