JPS5821884A - Ultraviolet gas laser device - Google Patents

Abstract

PURPOSE:To enable to repetitively operate a laser device and to inexpensively select and use a material which can readily selects the resistance value and which is readily treated by connecting a condenser directly to discharging electrodes so that the electrodes have higher than 0.05OMEGAcm of resistivity and non- inductive property. CONSTITUTION:A condenser 13 in a laser tube enclosure 11 is connected directly to a discharging electrode 12 or a discharging electrode holding material 19. The electrode 12 is selected for the resistivity of the component materials to a value higher than 0.05OMEGAcm, and is constructed in the shape becoming non-conductive of the using frequency. The pulse current is limited unitl the resistivity of the electrode 12 is up to 0.05OMEGAcm, and the sharpness of the waveform does not become obtuse. The electrode material may include, in addition to carbon, nichrome alloy, silicon, tantalum. The shape of the electrode may formed in the shape to set the self-inductance to zero to the current which flows through the main discharging gap.

Description

[Detailed Description of the Invention] Misfire 8) 4 is FIATed into an ultraviolet gas laser device with excellent laser characteristics.

In recent years, much research has been progressing on gas lasers for obtaining powerful laser beams with wavelengths in the ultraviolet region of 200 to 300 nanometers.6 In the schematic diagram of T. Jubei's laser shown in Figure 1, the filler gas is nitrogen, Noble gas (e.g. argon, krypton) or noble gas halogen (e.g. Xs (!1
, ArC1, KrF), and connect the discharge in the envelope (11 (usually a glass tube) close to the pole 121.
Leading wire (to)! The capacitor (31!) is connected in parallel.Both ends of the capacitor (3) are connected to a DC power source and charged.The pulse voltage sent from the charged capacitor +31 causes a glow discharge between the discharge currents (2). The source of the laser is obtained.When a rare gas compound or a rare gas halogen is irradiated with an electron beam, a rare gas excimer is generated, so a laser that uses a rare gas or a rare gas halogen is called an excimer laser. When obtaining an element, the lifetime of the upper laser level (40 nanoseconds) is extremely shorter than the lifetime of the lower laser level (10 microseconds).
In order to realize laser oscillation, the pulse current flowing through the circuit due to the pulse voltage must have a steep rise. Discharge 1 for a pulse wave current with a steep rise
The inductance component possessed by the pole (21 and the capacitor (31) (7) and Gunsugi Jitsume had a large inductance component (affected), and good performance could not be obtained. Vessel (1
Once discharge starts in 1, the discharge circuit (arrow (
4)).

Since the capacitor (317) is formed in contact with the capacitor, a large current of up to 104 amperes can flow through it. At such a large current, it is necessary to maintain the glow discharge.
and easily induce arc discharge. The arc discharge generates high heat, thereby causing the laser envelope to become a molecular gas! The sputtering action of atoms dissociating causes damage to the electrodes and destroys the capacitor! This may cause problems such as damage to the laser, and the lifespan of the laser will be significantly shortened. That tanu number 1
The laser with the configuration shown in the figure has about 10 parnus (10f) per second.
iz) laser oscillation was the limit. If you want to achieve more rapid and repeated operation, you can run an expensive and expensive gas and make it disposable.

Massive fan and cooler! The gas had to be forced to circulate (somehow).

The factor that influences the increase in the output of a laser is that the steepness of the rise in the discharge current at the wave front of the discharge current pulse is large, and the deviation value of the discharge current itself does not make any contribution to the interview. Discharge current there! Since it is advantageous to limit the rise of the discharge current and make it steeper, attempts have been made to connect a current limiting resistor in series with the discharge circuit.

The T-ring shown in the second frame shows the circuit configuration fIl in a conventional rare gas laser or 9-element laser. Laser tube envelope 1
Install only the discharge pole (2) in 11.

The purpose of this is to limit the discharge current flowing to the discharge circuit +41 by connecting the capacitor +31, the discharge current limiting resistor f51'z, and the envelope (11) to the outside of the discharge circuit +41. , resistor (51 → electrode (2) → capacitor + 31) Since the wavefront of the discharge current pulse is blunted due to the inductance of the Y-circuit T circuit, it may be possible to oscillate the laser with a rare gas laser. In field gas lasers, experiments have shown that weak oscillations at low repetition frequencies are underestimated.

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks and to provide an ultraviolet gas laser device having a relatively low furnace temperature and excellent laser characteristics. The key point of this invention is the capacitor inside the laser tube envelope! Connect directly to the discharge electrode or discharge chamber retaining material, and use JF! Two discharge chambers @! The resistivity of the material used for this purpose was selected to be 0.05 Ωcm or more, and the shape of the discharge chamber was configured to be non-inductive at the operating frequency.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention shown in the drawings will be clearly explained below. Third
1!21 is a sectional view on the T side showing the first embodiment of the present invention.

In Figure 3, the gas is 911, which is a rare gas halogen,
all is the laser lu, α2 is the discharge electrode, 0ζ is the capacitor built in the tube 011 and connected to the discharge electrode holding material 09 directly without any intervention, a? l is the trigger pulse application terminal, (2) is ii! ,' indicates a flowing madder pressure terminal. Trigger pulse! When applied to terminal 0η, Ll→
C2 → L2 → electrode a4 → gap (1 & 1 → capacitor α3
A discharge current flows as shown, and the capacitor α31 is charged. The light that occurs in this sharp discharge gap a0 is the main discharge gap 09! Irradiation T. Immediately after that, discharge electrode ■ and electrode holding material α
! 1 (for example, made of aluminum), a glow discharge exists between the two. This discharge starts laser oscillation. By repeating the application of the trigger pulse quickly, the single discharge becomes faster (and the laser oscillation can be performed up to 250 times per second.) It is assumed that a plurality of electrodes are formed in the direction of the tube axis and arranged like the ends of a comb. Only one of them is shown in Figure 3. Its resistivity is 0.3 Ωcm''C, which limits the pulse current and blunts the waveform steepness.
Capable of high-speed repetitive operation of 50 Hz. Resistivity! I tried changing it and experimenting with it.

Substantially the same effect as described above was obtained up to 0.05 Ωcm, and the effect was insufficient below that. 0.3Ωcm or more and T
This makes it possible to perform high-speed repetitive operation at 250 Hz, which is optimal.

The resistivity of the material commonly known as graphite is usually 1O-s.
It is inappropriate to use graphite as the electrode material of the present invention, and a material with a resistivity higher than that of graphite is used. In addition to carbon, electrode materials include nichrome alloy, silicon, and tantalum! Can be used for carbon +4-resistance (
It is convenient to use because it is easy to select fa. The thicker the resistivity is than 0.3Ωcrn, the more the length of the electrode can be adjusted, which is advantageous in achieving non-visit conductivity. In addition, the electrode shape is a short cylinder, but this can be any shape that can be considered to have zero self-inductance against the current flowing through the main discharge gap, and it can be a thin cylinder with a large diameter. You can also do it. 1F and FIG. 3, the use of the preliminary discharge gap ae is effective in effectively preventing the occurrence of arc discharge.

When the supply of electrons necessary to maintain a glow discharge becomes insufficient, the discharge itself forms an arc spot with a sieve temperature, and the lack of electrons is compensated for by thermionic emission, causing an arc discharge. 7. Pre-ionization has the effect of directly replenishing electrons on the cathode surface and between the electron beams due to the ionization action of the ultraviolet edge, and requires supplementary illumination of electrons on the cathode surface by an arc spot. This is because it becomes C. Therefore, the present invention makes it possible to effectively limit the discharge current based on the arc phenomenon (not only can concentration of discharge be prevented)
By using the preliminary chamber wI device Z together, the occurrence of arc discharge can be more effectively prevented.

Next, FIG. 4 is a side sectional view of a T laser device according to a second embodiment of the present invention, in which electrodes (12 to 71 planar plates are arranged parallel to the tube axis). The third cause and times-
The signs are the same! The figure shows a pre-ionization device. Capacitor a'' in Figure 3 is the light source of the preliminary 4rL separation and the head of the main discharge! However, the capacitor u31 in FIG. 4 is involved only in the main discharge. The pre-ionization device in FIG. 4 has a plurality of golden rings fitted onto a cylindrical insulator, which are slightly in front of each other.

When a high voltage is applied to both ends, simultaneous discharge can be achieved in series. The source of this separation of pre-positions is then a single glow discharge 'r' along the laser tube axis in the main discharge gap α.
I live here. At this time, the material of the discharge *pole aZ is the same as that shown in FIG. 3, but it has a planar shape, and the discharge becomes more uniform.

The output has nearly doubled, and when a vinyl chloride resin tube is used instead of a glass tube as the laser tube envelope αV, the absorption rate of chlorine and fluorine gases decreases, especially in excimer lasers. Compared to glass tubes, the lifespan of a single gas injection is more than twice as long.

In addition to being connected to the electrode supporting material, the capacitor can also be connected to the electrode itself.

Thus, according to the present invention, in a nitrogen laser or excimer laser device capable of generating ultraviolet laser beams, a discharge tW is obtained.
By appropriately selecting the resistance value and shape of the current pulse, it is possible to easily and effectively limit the discharge of the current pulse, without dulling the steepness of the rise.

One thing is that concentration of discharge due to arc phenomenon can be prevented.

Therefore, the so-called laser characteristics such as ηλ, which allows high-speed repetitive operation and high output at the laser source, are excellent. and! The electrode material is relatively inexpensive, and the resistance value can be easily selected and processed, and it is also easy to obtain a material that is resistant to heat and sputtering, making it useful as a laser device. Furthermore, since there is no gas circulation, the device becomes compact.

[Brief explanation of the drawing]

1 [N] FIG. 2 is a T diagram showing the configuration of a conventional gas laser device, and FIGS. 3 and 4 are T diagrams showing the configuration of the first and second embodiments of the present invention. 111 Qll...Laser tube envelope +210・
・・Discharge 1 pole 131 +1:1−・・Capacitor
(5)...Current limiting resistor I...needle-shaped as pole
αS...Main discharge gap ae...Preliminary discharge gap
α9...1! Pole holding material holder...Preliminary ionization device patent applicant Pilot Mannensha Co., Ltd. Ink 8 Ben Ushi Eisuke Ogi

Claims (1)

[Scope of Claims] 1. In an ultraviolet gauze gas laser which has a capacitor connected in parallel to the discharge chamber frames facing each other, and which generates a glow discharge in a gas by applying a pulsed voltage, the capacitor is Y
'11 directly connected to the discharge electrode or the discharge electrode holding material, and the discharge electrode has a resistivity of 0. '05Ωcm
The ultraviolet gas laser equipment selected above has a shape that is non-inductive at the operating frequency and has seven characteristics. 2. The ultraviolet gas laser device according to claim 1, characterized in that the preliminary discharge opening is provided at a position opposite to the main discharge gap of the discharge electrode.