JPH0542839B2 - - Google Patents
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- Publication number
- JPH0542839B2 JPH0542839B2 JP1233746A JP23374689A JPH0542839B2 JP H0542839 B2 JPH0542839 B2 JP H0542839B2 JP 1233746 A JP1233746 A JP 1233746A JP 23374689 A JP23374689 A JP 23374689A JP H0542839 B2 JPH0542839 B2 JP H0542839B2
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- Prior art keywords
- discharge
- gas
- laser
- max
- silent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 230000003287 optical effect Effects 0.000 claims description 6
- 239000003989 dielectric material Substances 0.000 claims description 5
- 239000007789 gas Substances 0.000 description 76
- 230000010355 oscillation Effects 0.000 description 31
- 238000010586 diagram Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 5
- 239000002184 metal Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 230000005284 excitation Effects 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000008033 biological extinction Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
- 230000005593 dissociations Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/097—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser
- H01S3/0971—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser transversely excited
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
Description
【発明の詳細な説明】
この発明は、無声放電式レーザに係り、とくに
無声放電式CO2レーザのレーザ媒質として使用す
るガス成分の最適化に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silent discharge laser, and particularly to optimization of gas components used as a laser medium in a silent discharge CO 2 laser.
無声放電はレーザの励起に関して全く新しい放
電であり、発明者らの研究以外その前例をみない
ものである。レーザ媒質として用いるガスの最適
成分についてもこれまで全く知られていなかつた
のが実情であることを、説明に先立つて述べてお
く。 Silent discharge is a completely new type of discharge with respect to laser excitation, and has no precedent other than the research conducted by the inventors. Before proceeding with the explanation, it should be stated that the actual situation is that the optimum components of the gas used as the laser medium have not been known at all until now.
まず、無声放電式CO2レーザについて、直交形
レーザを例にとつて説明する。レーザ用の媒質ガ
スは、従来、直交形Ｄ，Ｃ、放電式CO2レーザで
用いられるCO2−CO−N2−He混合ガスとほとん
ど同じ組成で、これらのモル分率が５−２−15−
78％、気体圧が100Torrである。第１図は無声放
電式CO2レーザの構成図、第２図は、第１図の
−線断面図を示す。これらの図において、１
ａ，１ｂは電極で幅が２cm、長さが２ｍであり、
２ａ，２ｂは電極１ａ，１ｂの各外面を被覆する
誘電体で、これらは約10nFの静電容量を有して
いる。３は両電極１ａ，１ｂで挾まれる無声放電
空間で、放電空隙長ｄ＝20mmである。すなわち、
放電空間３の光軸方向断面の幅と空隙長が略等し
くなつている。また、４は絶縁物からなるガスガ
イド、５は熱交換器、６はフロア、７は金属製の
容器で、電極１ａとの最短距離Ｌ＝12cmであり、
８は交流電源、９は全反射鏡、１０は部分反射
鏡、１１はレーザ出力光である。 First, a silent discharge CO 2 laser will be explained using an orthogonal laser as an example. The medium gas for the laser has almost the same composition as the CO 2 -CO-N 2 -He mixed gas conventionally used in orthogonal D, C, and discharge type CO 2 lasers, and the molar fraction of these is 5-2- 15−
78%, gas pressure is 100Torr. FIG. 1 is a block diagram of a silent discharge type CO 2 laser, and FIG. 2 is a sectional view taken along the line -- in FIG. 1. In these figures, 1
a and 1b are electrodes with a width of 2 cm and a length of 2 m;
Dielectrics 2a and 2b cover the outer surfaces of the electrodes 1a and 1b, and have a capacitance of about 10 nF. 3 is a silent discharge space sandwiched between both electrodes 1a and 1b, and the discharge gap length d=20 mm. That is,
The width of the cross section of the discharge space 3 in the optical axis direction and the gap length are approximately equal. Further, 4 is a gas guide made of an insulator, 5 is a heat exchanger, 6 is a floor, 7 is a metal container, and the shortest distance L from the electrode 1a is 12 cm.
8 is an AC power supply, 9 is a total reflection mirror, 10 is a partial reflection mirror, and 11 is a laser output light.
第１図、第２図に示す無声放電式CO2レーザ
で、交流電源８により電極１ａ，１ｂ間に正弦波
電圧Ｖを印加すると、電極の電圧−電流の時間変
化を示す第３図からわかるように、時刻tAで放電
期間に入つてパルス状放電電流の重畳した電流
が流れ、時刻tBで放電が休止し、tB−tCが非放電
期間となり、tC−tDが逆極性の放電期間である。
放電空間にかかる電圧Vgapは、第３図に示すよ
うに、放電期間では一定値V*（約2KV）であり、
これは放電維持電圧と呼ばれる。電圧Ｖと電流
とを掛けて得られるのは瞬間的な電力である。こ
のように無声放電では放電エネルギーは時間的に
不連続的に注入されるが、レーザの励起、発振出
力は電源周波数として10KHz前後、ガス圧力とし
て100Torr前後の条件下ではいずれも時間的に大
体連続的であることがわかつている。 When a sinusoidal voltage V is applied between the electrodes 1a and 1b by the AC power supply 8 in the silent discharge type CO 2 laser shown in Figs. 1 and 2, it can be seen from Fig. 3 that shows the time change of the electrode voltage-current. As shown in the figure, the discharge period begins at time t A , a current with a superimposed pulsed discharge current flows, the discharge stops at time t B , t B − t C becomes a non-discharge period, and t C − t D is reversed. This is the polar discharge period.
As shown in Figure 3, the voltage Vgap applied to the discharge space is a constant value V * (approximately 2KV) during the discharge period.
This is called the discharge sustaining voltage. What is obtained by multiplying voltage V and current is instantaneous power. In this way, in silent discharge, the discharge energy is injected discontinuously in time, but the laser excitation and oscillation output are approximately continuous in time under conditions of a power supply frequency of around 10KHz and a gas pressure of around 100Torr. It is known that this is true.
無声放電によつてレーザ媒質は励起され、全反
射鏡９、部分反射鏡１０で構成される光共振器内
で発振が生じ、発振光の一部がレーザ出力１１と
して外に取り出される。レーザ媒質ガスはフロア
６で加速され、放電空間３を数10ｍS-1の高速で
通過した後、熱交換器５で冷却されて容器７内を
循環する。 The laser medium is excited by the silent discharge, oscillation occurs within the optical resonator constituted by the total reflection mirror 9 and the partial reflection mirror 10, and a part of the oscillation light is extracted outside as a laser output 11. The laser medium gas is accelerated on the floor 6, passes through the discharge space 3 at a high speed of several tens of mS -1 , is cooled by the heat exchanger 5, and circulates within the container 7.
そして、混合ガスCO2−CO−N2−H2＝５−２
−15−78（モル分率）、圧力、ｐ＝100Torr、周波
数10KHzでの印加電圧の正の最大値から負の最大
値までの値（peak−to−peak値、以下ピークツ
ウピーク値という）Vppと時間平均した放電電力
Wdと得られた発振出力Wrとの関係を第４図に示
す。第４図において、Vpp＝15KVのとき、発振
効率η（＝Wr／Wd）＝6.2％で発振するCO2レー
ザが得られた。印加電圧Vppを前述した以上に上
げると、容器７と電極１ａとの間に放電が発生
し、むだな放電電力がそこで消費されるのは勿
論、放電ノイズで交流電源８が損傷を受けるなど
の不都合を生じる。 Then, the mixed gas CO 2 −CO−N 2 −H 2 =5−2
-15-78 (mole fraction), pressure, p = 100 Torr, the value from the maximum positive value to the maximum negative value of the applied voltage at a frequency of 10 KHz (peak-to-peak value, hereinafter referred to as peak-to-peak value) Vpp and time-averaged discharge power
FIG. 4 shows the relationship between Wd and the obtained oscillation output Wr. In FIG. 4, when Vpp=15KV, a CO 2 laser was obtained that oscillated with an oscillation efficiency η (=Wr/Wd)=6.2%. If the applied voltage Vpp is increased above the above-mentioned level, a discharge will occur between the container 7 and the electrode 1a, which will not only waste discharge power but also cause damage to the AC power supply 8 due to discharge noise. cause inconvenience.
印加電圧Vppを増大させるのは、放電電力Wd
を増大させ発振出力を大きくし、発振効率η（＝
Wr／Wd）をさらに上昇させようとして試みたこ
とであるが、これによつて、前記ガス組成では放
電電力の増大が困難であるという問題があること
がわかつた。また、ガス組成にH2Oを含むと、
H2OはCO2ガスの振動準位（レーザ上準位）と同
程度のエレルギーレベルに振動準位を持ち、レー
ザ励起効率を劣化させるという問題があつた。 The applied voltage Vpp is increased by the discharge power Wd
The oscillation output is increased by increasing the oscillation efficiency η (=
Although an attempt was made to further increase Wr/Wd), it was found that there was a problem in that it was difficult to increase the discharge power with the above gas composition. Also, if H 2 O is included in the gas composition,
H 2 O has a vibrational level at an energy level comparable to the vibrational level of CO 2 gas (laser upper level), which poses a problem in that it deteriorates laser excitation efficiency.
この発明は、前記ガス組成の問題に鑑み、放電
電力の増大が可能で、かつ発振出力、発振効率の
大きい無声放電式レーザを得るために、ガス組成
を最適化することを目的としてなされたものであ
る。 In view of the above gas composition problem, this invention was made with the aim of optimizing the gas composition in order to obtain a silent discharge laser that is capable of increasing discharge power, and has high oscillation output and oscillation efficiency. It is.
放電の電気的特性を研究した結果、無声放電の
放電電力Wdと印加電圧のピークツウピーク値
Vpp無声放電の放電維持電圧V*、電源周波数ｆ、
電極の静電容量Cdの間には近似的に次式が成立
することが明らかになつた。 As a result of researching the electrical characteristics of discharge, the discharge power Wd of silent discharge and the peak-to-peak value of applied voltage were determined.
Vpp silent discharge discharge sustaining voltage V * , power supply frequency f,
It has become clear that the following equation holds approximately between the capacitances Cd of the electrodes.
Wd＝ｆ・Cd・2V*（Vpp−2V*） ……(1)
そして、放電維持電圧V*は気体圧力ｐ、放電
空隙長ｄと、
2V*＝2pd＋Ｂ ……(2)
（ただし、Ａ、Ｂはガスの常数である）
の関係で結ばれる。またＢは小さく通常無視する
ことができるので、
2V*＝Apd ……(3)
で表わすことができる。なお、以後Ａを気体常数
と呼ぶ。印加できるVppmaxは同様に、かつ50％
の安全率を見込んで、
Vppmax＝２／３（ApL＋Ｂ）≒２／３ApL ……(4)
（ここで、Ｌは高電圧無声放電電極と容器あるい
は他の接地金属部分との最短距離である）
で表わせることが明らかになつた。 Wd=f・Cd・2V * (Vpp−2V * )...(1) Then, the discharge sustaining voltage V * is the gas pressure p, the discharge gap length d, and 2V * =2pd+B...(2) (However, A , B is a gas constant). Also, since B is small and can usually be ignored, it can be expressed as 2V * = Apd (3). Note that A is hereinafter referred to as a gas constant. The Vpp max that can be applied is the same and 50%
Taking into account the safety factor of ) It became clear that it can be expressed as
以上の結果を総合すると、放電電力Wdの上限
Wdmaxは、
Wdmax≒ｆ・Cd・Apd（２／３ApL−Apd）＝ｆ・Cd・A2p2
d（２／３Ｌ−ｄ）……(5)
となる。 Combining the above results, the upper limit of the discharge power Wd
Wd max is, Wd max ≒ f・Cd・Apd (2/3ApL−Apd)=f・Cd・A 2 p 2
d(2/3L-d)...(5)
前記(5)式に基いて、レーザの構造を変えること
なく、Wdmaxを増大させるには、
(i) 電源周波数ｆを上げる
(ii) 電極の静電容量Cdを上げる
(iii) 気体常数Ａの大きなガス組成を見出す
(iv) 気体圧力ｐを上げる
ことの４つの手段が考えられる。 Based on the above equation (5), in order to increase Wd max without changing the laser structure, (i) increase the power supply frequency f (ii) increase the electrode capacitance Cd (iii) gas constant A (iv) Find a large gas composition of (iv) There are four possible ways to increase the gas pressure p.
しかし、(i)の電源周波数ｆを上げることは、電
源製作費用が高くなる上に、電源のエネルギー効
率が悪くなる欠点がある。(ii)の電極の静電容量
Cdを上げるために、電極面積を大きくすれば装
置の大形化を伴い、また誘電体の厚さを薄くすれ
ば誘電体の耐電圧性能が低下し、さらに誘電体の
誘電率を上げれば誘電率の高い材質は一般に耐電
圧性能が不良であるという欠点があり、前記いず
れかの手段を採る必要があるので、いずれかの欠
点が生じる。(iv)の気体圧力ｐを上げる方法は、放
電電力の上限Wvdmaxを上げる効果があるが、同
時に発振に必要な最低の放電電力Woも大略気体
圧力ｐの２乗p2に比例して上がるので、結局レー
ザの効率を上げることができず、よい手段ではな
い。 However, raising the power supply frequency f in (i) has the disadvantage that the power supply manufacturing cost increases and the energy efficiency of the power supply deteriorates. (ii) The capacitance of the electrode
In order to increase the Cd, increasing the electrode area will increase the size of the device, decreasing the thickness of the dielectric will reduce the withstand voltage performance of the dielectric, and increasing the dielectric constant will increase the dielectric strength. A material with a high ratio generally has a disadvantage of poor voltage resistance performance, and since it is necessary to take one of the above measures, one of the disadvantages occurs. The method (iv) of increasing the gas pressure p has the effect of increasing the upper limit Wvd max of the discharge power, but at the same time the minimum discharge power Wo required for oscillation also increases approximately in proportion to the square of the gas pressure p 2 Therefore, in the end, it is not possible to increase the efficiency of the laser, so it is not a good method.
そこで、この発明では、気体常数Ａが大きく、
かつレーザ発振に好適な媒質ガスの組成を得て、
高出力、高効率の無声放電式CO2レーザを実現さ
せようとするものである。 Therefore, in this invention, the gas constant A is large,
and obtain a medium gas composition suitable for laser oscillation,
The aim is to realize a high-output, high-efficiency silent discharge CO 2 laser.
ところで、気体常数Ａのガスの種類への依存性
は、ここで初めて明らかにされることであり、こ
れまでにその異存性を知るべき根拠となる研究は
全くない。これは、CO2レーザに無声放電を応用
することは、発明者らによつて最初になされたと
いう事情に基いている。 By the way, the dependence of the gas constant A on the type of gas is being clarified for the first time here, and there has been no research to date that provides a basis for knowing its existence. This is based on the fact that the inventors were the first to apply silent discharge to a CO 2 laser.
無声放電は、第３図にも示したように、電圧印
加の１サイクル中に放電期間と非放電期間とがあ
り、放電期間の時間的並びに空間的な平均の放電
電圧がV*である。放電期間では、さらに分散し
たパルス状の微細な放電が発生と消滅を繰返すこ
とが、空気中並びに酸素中の無声放電について明
らかにされており、CO2レーザの媒質ガス中でも
同様の現象が生じるものと推定される。すなわ
ち、無声放電は、これ自体が放電の点火と、放電
の維持と、滅火という互にきわめて異なつた現象
を全て含んでいるので、前記電圧V*の絶対値、
ガスの種類への依存性はいずれも火花放電、グロ
ー放電などの研究分野からの推定は不可能であつ
た。 As shown in FIG. 3, silent discharge has a discharge period and a non-discharge period in one cycle of voltage application, and the temporal and spatial average discharge voltage of the discharge period is V * . It has been revealed that during the discharge period, even more dispersed pulse-like fine discharges occur and disappear repeatedly for silent discharges in air and oxygen, and a similar phenomenon occurs in the medium gas of CO 2 lasers. It is estimated to be. That is, since silent discharge itself includes all of the very different phenomena of ignition of discharge, maintenance of discharge, and extinction of discharge, the absolute value of the voltage V * ,
It was impossible to estimate the dependence on the type of gas from research fields such as spark discharge and glow discharge.
以下に気体常数Ａのガス組成依存性を実験結果
に基いて説明する。 The dependence of the gas constant A on the gas composition will be explained below based on experimental results.
第１図、第２図に基いて前述した比較例のもの
と類似のCO2−CO−N2−Heの混合ガス中で、
CO2が５％、COが２％を保つたまま、N2のモル
分率を変化させた場合の2V*の変化の一例を第５
図に示す。これによる気体常数Ａの変化およびこ
れに伴う放電電力の上限Wdmaxの変化を第６図に
示す。さらに、それぞれの場合の発振に必要な最
小の放電電力Wo、発振出力Wrと放電電力Wdの
増分の比η0（＝ΔWr／ΔWd）の変化を発振実験の
結果から第７図に示す。Woとη0を用いれば発振
出力の上限Wrmaxと放電電力の上限Wdmaxとは
Wrmax＝（Wdmax−Wo）η0 ……(6)
で結ばれ、発振効率ηの上限ηmaxは
ηmax＝Wrmax／Wdmax＝（１−Wo／Wdmax）η0……(7)
となる。 In a mixed gas of CO 2 −CO−N 2 −He similar to that of the comparative example described above based on FIGS. 1 and 2,
An example of the change in 2V * when changing the molar fraction of N2 while keeping CO2 at 5% and CO at 2% is shown in Part 5.
As shown in the figure. The resulting changes in the gas constant A and the associated changes in the upper limit Wd max of the discharge power are shown in FIG. Further, FIG. 7 shows the changes in the minimum discharge power Wo required for oscillation and the ratio η 0 (=ΔWr/ΔWd) of the increment of the oscillation output Wr and the discharge power Wd in each case based on the results of the oscillation experiment. Using Wo and η 0 , the upper limit Wr max of oscillation output and the upper limit Wd max of discharge power are connected by Wr max = (Wd max − Wo) η 0 ...(6), and the upper limit η max of oscillation efficiency η is η max =Wr max /Wd max =(1−Wo/Wd max )η 0 (7).
第６図、第７図の結果から発振効率の上限
ηmax、発振出力の上限Wrmaxを求めた結果を第８
図に示す。この第８図からわかるように、放電電
力投入の観点からはN2のモル分率35％以上で比
較例の２倍以上の効果が得られ、発振効率上昇の
観点からはN260％〜70％が最適、N235〜90％で
最適値の80％を達成できる。 The upper limit η max of the oscillation efficiency and the upper limit Wr max of the oscillation output were determined from the results shown in Figs. 6 and 7.
As shown in the figure. As can be seen from Fig. 8, from the viewpoint of discharging power input, an effect more than twice that of the comparative example can be obtained when the molar fraction of N 2 is 35% or more, and from the viewpoint of increasing oscillation efficiency, an effect of 60% or more N 2 is obtained. 70% is optimal, and 80% of the optimal value can be achieved with N 2 35-90%.
理解を容易にするために、１例としてN2のモ
ル分率60％の実施例と比較例の15％とを対比して
Wd、Wr、Vppの関係を第９図に示す。 For ease of understanding, as an example, an example with a mole fraction of N 2 of 60% is compared with a comparative example of 15%.
The relationship among Wd, Wr, and Vpp is shown in FIG.
N260％の実施例ではVppは26KVまで印加でき
るようになりWdは最大6.4KW、Wrは最大
0.72KWとなり、η＝11.2％の無声放電式CO2レ
ーザを実限することができた。 In the N 2 60% example, Vpp can be applied up to 26KV, Wd is up to 6.4KW, and Wr is up to
The output was 0.72KW, and we were able to achieve the practical limit of a silent discharge CO 2 laser with η = 11.2%.
以上説明したように前述の実施例によれば、
N2のモル分率を35〜90％に選ぶことにより、放
電電力を大きく投入することが可能となり、かつ
発振効率、発振出力の大きな無声放電式CO2レー
ザを実現することが可能になる。 As explained above, according to the above embodiment,
By selecting the molar fraction of N 2 to be 35 to 90%, it becomes possible to input a large amount of discharge power, and it becomes possible to realize a silent discharge CO 2 laser with high oscillation efficiency and oscillation output.
なお、前述の実施例のガス組成の最適化は、第
１図、第２図に示す装置において、電極１ａと容
器７あるいはその他の接地金属部分との間に放電
破壊が生じないことを条件として、Vppmaxの前
記式(4)を得たことが出発点の１つになつている。
装置の構造を、電極１ａと容器７あるいは他の接
地金属部分との距離Ｌが十分に長いように構成し
た場合には、Vppmaxは誘電体２ａ，２ｂの耐電
圧性能で決まる大きな値（40KV）になる。こ
の場合には前記式(1)でVppmax＞2V*を仮定すれ
ば明らかなように、
Wdmax〓Ａ・Vppmax
になる。気体常数Ａの大きいガス組成によつて、
放電電力を増大し、かつ発振効率の高いレーザを
得る効果は、この場合も発揮できる。 The optimization of the gas composition in the above-mentioned embodiments is carried out on the condition that no discharge breakdown occurs between the electrode 1a and the container 7 or other grounded metal parts in the apparatus shown in FIGS. 1 and 2. , Vpp max is obtained from equation (4) above, which serves as one of the starting points.
If the device structure is configured such that the distance L between the electrode 1a and the container 7 or other grounded metal part is sufficiently long, Vpp max will be a large value (40KV) determined by the withstand voltage performance of the dielectrics 2a and 2b. )become. In this case, if we assume that Vpp max > 2V * in the above formula (1), as is clear, Wd max 〓A·Vpp max . Due to the gas composition with a large gas constant A,
The effect of increasing the discharge power and obtaining a laser with high oscillation efficiency can also be achieved in this case.
次に、この発明の他の実施例について説明す
る。 Next, other embodiments of the invention will be described.
前述した実施例ではCO25％、CO2％の一定モ
ル分率でN2のモル分率を変化させた場合につい
て述べたが、ガス中の成分COは、もともとCO2
がCOとO2に解離することによりレーザのガス組
成が変化し、長時間ガス封じ切りの条件下で発振
効率が低下するのを防ぐために用いられたもので
ある。 In the example described above, the case was described in which the mole fraction of N2 was changed at a constant mole fraction of 5% CO2 and CO2 %, but the component CO in the gas was originally CO2
This was used to prevent the gas composition of the laser from changing due to its dissociation into CO and O 2 and the oscillation efficiency decreasing under conditions where the gas is shut off for a long time.
したがつて、ガスを入れ替えながら運転する場
合には、COは必ずしも必要ではない。また、ガ
ス封じ切りで長時間効率のよい安定な運転を行な
いたい場合には、COのモル分率を最適値に設定
しておくことが望ましい。 Therefore, CO is not necessarily necessary when operating while replacing gas. In addition, if you want to perform efficient and stable operation for a long time with the gas shut off, it is desirable to set the mole fraction of CO to an optimal value.
以下にCOを含まない場合およびCOを含む場合
のそれぞれについて述べる。 The case where CO is not included and the case where CO is included are described below.
まず、CO2−N2−He混合ガスにおいて、気体
定数Ａと組成の関係を第１０図に示す。第１０図
において、気体定数Ａの値は専らN2によつて決
定され、CO2、Heのモル分率が与える影響は小
さいことがわかる。したがつて、Wdmaxを上昇さ
せる目的は第６図の場合と同様にN2のモル分率
35％以上で達成できる。発振効率も同時に上昇さ
せる効果は、CO2が１〜10％の範囲で達成でき
る。CO2のモル分率がこの範囲を外れるとη0は10
％以下になり、レーザ発振器としては実用性のな
いものとなる。 First, FIG. 10 shows the relationship between the gas constant A and the composition of a CO2 - N2 -He mixed gas. In FIG. 10, it can be seen that the value of the gas constant A is determined exclusively by N 2 and the influence of the mole fractions of CO 2 and He is small. Therefore, the purpose of increasing Wd max is to increase the mole fraction of N 2 as in the case of Figure 6.
Achieved at 35% or higher. The effect of simultaneously increasing the oscillation efficiency can be achieved when the CO 2 content is in the range of 1 to 10%. When the mole fraction of CO 2 is outside this range, η 0 is 10
% or less, making it impractical as a laser oscillator.
次に、CO2−CO−N2−He混合ガスにおいては
第１１図に示すように、COのモル分率が０〜５
％で、気体常数Ａは急激に大きくなる。一方、η0
はCOのモル分率が10％を越えると10％以下にな
る。CO2モル分率の異なる状態での結果を総合す
ると、次のように伝える。すなわち、COのモル
分率はCO2のモル分率の０〜２倍の範囲で、かつ
N2のモル分率が35〜90％の範囲であれば、
Wdmaxを大きく、かつηmaxを大きくする結果が発
揮でき、さらにガス封じ切り運転条件下でも長時
間安定した発振出力のCO2レーザが得られる。 Next, in the CO 2 -CO-N 2 -He mixed gas, as shown in Figure 11, the mole fraction of CO is 0 to 5.
%, the gas constant A increases rapidly. On the other hand, η 0
becomes less than 10% when the mole fraction of CO exceeds 10%. Combining the results under different CO2 mole fractions, we can tell the following. That is, the mole fraction of CO is in the range of 0 to 2 times the mole fraction of CO2 , and
If the mole fraction of N2 is in the range of 35-90%,
It is possible to achieve the results of increasing Wd max and η max , and furthermore, it is possible to obtain a CO 2 laser with stable oscillation output for a long time even under gas-sealed operation conditions.
さらに、Heの一部をArに置換したガスでも、
この発明は有効である。すなわち、CO2−CO−
N2−He−Ar混合ガスでArのモル分率が気体常
数Ａに与える影響の一例を第１２図に示す。この
第１２図からArのモル分率は気体常数Ａの値に、
したがつてWdmaxに余り影響を与えないことがわ
かる。一方、Arのモル分率が17％を越えすなわ
ちHeのモル分率を越えると、η0が10％未満とな
りηmaxを上昇させる効果が小さくなる。そして、
CO2のモル分率が１〜10％、COのモル分率が
CO2の０〜２倍のいずれの範囲についても、大体
同じ状態であつた。すなわち、CO2のモル分率が
１〜10％、COがCO2の０〜２倍、N2のモル分率
が35〜90％のすべてを満たし、かつArがHeの０
〜１倍の範囲ではWdmaxを大きくし、かつηmaxを
大きくするガス組成が得られる。そして、Heを
Arに置換することは、Heが高価なガスであるか
らレーザの運転費用が安くなる実用的効果が大き
い。 Furthermore, even if a part of He is replaced with Ar,
This invention is effective. That is, CO 2 −CO−
FIG. 12 shows an example of the influence of the mole fraction of Ar on the gas constant A in a N 2 -He-Ar mixed gas. From this Figure 12, the mole fraction of Ar is the value of the gas constant A,
Therefore, it can be seen that it does not have much influence on Wd max . On the other hand, when the mole fraction of Ar exceeds 17%, that is, exceeds the mole fraction of He, η 0 becomes less than 10% and the effect of increasing η max becomes small. and,
The mole fraction of CO 2 is 1-10%, the mole fraction of CO is
The situation was almost the same in any range of 0 to 2 times CO 2 . That is, the mole fraction of CO2 is 1 to 10%, CO is 0 to 2 times that of CO2 , the mole fraction of N2 is 35 to 90%, and Ar is 0 to 10% of He.
In the range of ~1 times, a gas composition that increases Wd max and increases η max can be obtained. And He
Since He is an expensive gas, replacing it with Ar has a great practical effect of lowering the operating cost of the laser.
前述した実施例では、いずれもガス流と光軸方
向が直交する直交形の無声放電式CO2レーザを示
したが、軸流形の構成の場合にもVppmaxを決定
する距離Ｌの対象となる個所が異なるだけで、こ
の発明を適用でき、その効果も同じである。 In the above-mentioned embodiments, a silent discharge type CO 2 laser is shown in which the gas flow and the optical axis direction are orthogonal to each other. The present invention can be applied and the effects are the same, with the only difference being in the parts.
第１３図は軸流形の無声放電式レーザの構成原
理図であり、断面円環状の絶縁管１５の電極１
ａ，１ｂに被覆された部分が誘電体２ａ，２ｂと
して働らき、電極１ａ，１ｂは絶縁層１４で包ま
れている。また、放電空隙長ｄは誘電体２ａ，２
ｂ間の距離と等しいため、放電空間３の光軸方向
断面の幅と空隙長は等しくなつている。更に全反
射鏡９、部分反射鏡１０は接地された金属製のミ
ラーホルダ１３で保持され、絶縁物からなるガス
ガイド４には図示してない熱交換器とブロアとが
接続されている。この実施例では電極１ａとミラ
ーホルダ１３との最短距離がVppmaxを決定する
距離Ｌとなる。 FIG. 13 is a diagram showing the principle of construction of an axial flow type silent discharge laser.
The portions covered by electrodes a and 1b act as dielectrics 2a and 2b, and electrodes 1a and 1b are surrounded by an insulating layer 14. Moreover, the discharge gap length d is the dielectric material 2a, 2
Since the distance between b and b is equal, the width of the cross section of the discharge space 3 in the optical axis direction and the gap length are equal. Further, the total reflection mirror 9 and the partial reflection mirror 10 are held by a grounded metal mirror holder 13, and a heat exchanger and a blower (not shown) are connected to a gas guide 4 made of an insulator. In this embodiment, the shortest distance between the electrode 1a and the mirror holder 13 is the distance L that determines Vpp max .
以上説明したように、この発明によれば、無声
放電式レーザのガス媒質として、少なくともCO2
−N2−Heの３種類のガス成分を含み、かつCO2
のモル分率が１〜10％かつN2のモル分率が35〜
90％の範囲の混合ガスを用いたことにより、放電
電力が大きく投入でき、発振効率の大きい、すな
わち、大出力のレーザを実現させることができる
という効果がある。 As explained above, according to the present invention, at least CO 2 is used as the gas medium of the silent discharge laser.
Contains three types of gas components: -N 2 -He, and CO 2
The mole fraction of N2 is from 1 to 10% and the mole fraction of N2 is from 35 to
By using a mixed gas in the 90% range, a large amount of discharge power can be input, and a high oscillation efficiency, that is, a high output laser can be realized.
なお、この発明において、ガス媒質として前記
CO2−N2−Heの混合ガスにCOを添加し、COの
モル分率がCO2のモル分率の２倍以下にすること
により、ガス封じ切り条件で長期間にわたり安定
した大出力のレーザを提供できる。また、ガス媒
質として前記CO2−N2−HeあるいはCO2−CO−
N2−Heの混合ガスのHeをArに一部置換し、Ar
のモル分率がHeの１倍以下にすることにより、
大出力無声放電式CO2レーザ用の安価なガスを提
供できる。 In addition, in this invention, the above-mentioned gas medium is used as the gas medium.
By adding CO to the CO 2 −N 2 −He mixed gas and making the mole fraction of CO less than twice the mole fraction of CO 2 , stable high output can be achieved for a long period of time under gas shut-off conditions. We can provide lasers. In addition, as a gas medium, the above-mentioned CO 2 −N 2 −He or CO 2 −CO−
By partially replacing He in the N 2 −He mixed gas with Ar,
By making the molar fraction of He less than 1 times that of He,
We can provide inexpensive gas for high-output silent discharge CO 2 lasers.
第１図は無声放電式CO2レーザの一例を示す側
面図、第２図は第１図の−線に沿う断面図、
第３図は第１図、第２図に示すレーザの電流・電
圧の説明図、第４図は比較例のガス組成での放電
電力、発振出力と印加電圧のピークツウピーク値
を示す図、第５図は放電維持電圧V*と気体圧力
ｐ、放電空隙長ｄの積pdとの関係を示す図、第
６図はガス中のN2のモル分率と最大放電電力
Wdmax、気体定数Ａの関係を示す図、第７図はガ
ス中のN2のモル分率と放電電力に対する発振出
力η0と発振に必要な最小放電電力Woの関係を示
す図、第８図はガス中のN2のモル分率と最大発
振効率ηmaxの関係を示す図、第９図はこの発明の
一実施例のガスにおける放電電力Wd、発振出力
Wrと印加電圧のピークツウピーク値Vppとの関
係を比較例のガスと比較して示した図、第１０図
は気体定数Ａに与えるCO2のモル分率の影響を
CO2−N2−He混合ガスについて示した図、第１
１図は気体定数Ａに与えるCOのモル分率の影響
をCO2−CO−N2−He混合ガスについて示した
図、第１２図は気体定数Ａに与えるArのモルの
分率の影響をCO2−CO−N2−He−Ar混合ガス
について示した図、第１３図ａおよびｂは軸流形
無声放電式CO2レーザにこの発明を適用した例を
示す側断面図および横断面図である。
１ａ，１ｂ……電極、２ａ，２ｂ……誘電体、
３……放電空間、４……ガスガイド、５……熱交
換器、６……ブロワ、７……容器、８……交流電
源、９……全反射鏡、１０……部分反射鏡、１３
……ミラーホルダ、１５……絶縁管。なお、図中
同一符号は同一または相当部分を示す。
Figure 1 is a side view showing an example of a silent discharge CO 2 laser, Figure 2 is a sectional view taken along the - line in Figure 1,
FIG. 3 is an explanatory diagram of the current and voltage of the laser shown in FIGS. 1 and 2, and FIG. 4 is a diagram showing the peak-to-peak values of discharge power, oscillation output, and applied voltage with a gas composition of a comparative example. Figure 5 shows the relationship between discharge sustaining voltage V * , gas pressure p, and discharge gap length d (pd), and Figure 6 shows the molar fraction of N2 in the gas and the maximum discharge power.
Figure 7 is a diagram showing the relationship between Wd max and gas constant A. Figure 7 is a diagram showing the relationship between oscillation output η 0 and minimum discharge power Wo required for oscillation with respect to the molar fraction of N 2 in the gas and discharge power. The figure shows the relationship between the molar fraction of N 2 in the gas and the maximum oscillation efficiency η max . Figure 9 shows the discharge power Wd and oscillation output in the gas of an embodiment of the present invention.
A diagram showing the relationship between Wr and the peak-to-peak value Vpp of the applied voltage in comparison with a comparative example gas, and Figure 10 shows the influence of the mole fraction of CO 2 on the gas constant A.
Diagram showing CO 2 −N 2 −He mixed gas, 1st
Figure 1 shows the influence of the mole fraction of CO on the gas constant A for a CO 2 -CO-N 2 -He mixed gas, and Figure 12 shows the influence of the mole fraction of Ar on the gas constant A. Figures 13a and 13b are side sectional views and cross sectional views showing an example in which the present invention is applied to an axial silent discharge CO 2 laser. It is. 1a, 1b... electrode, 2a, 2b... dielectric,
3... Discharge space, 4... Gas guide, 5... Heat exchanger, 6... Blower, 7... Container, 8... AC power supply, 9... Totally reflecting mirror, 10... Partially reflecting mirror, 13
...Mirror holder, 15...Insulation tube. Note that the same reference numerals in the figures indicate the same or corresponding parts.
Claims (1)
た１組の電極間に交流電圧を印加し、両電極で挟
まれる放電空間に無声放電を生じさせるようにし
た無声放電式レーザにおいて、上記放電空間のレ
ーザ光軸方向の断面における幅と空〓長を略等し
くなしかつ上記放電空間と光共振空間とを略重な
りあうように位置せしめると共に、ガス媒質は
H2Oを含まず少なくともCO2−N2−Heの３種類
のガス成分を含み、CO2のモル分率が１〜10％、
かつN2のモル分率が35〜90％の範囲にあること
を特徴とする無声放電式レーザ。 ２ ガス媒質はH2Oを含まず少なくともCO2−
CO−N2−Heの４種類のガス成分を含むことを
特徴とする特許請求の範囲第１項記載の無声放電
式レーザ。 ３ ガス媒質はH2Oを含まず少なくともCO2−
N2−He−Arの４種類のガス成分を含むことを特
徴とする特許請求の範囲第１項または第２項記載
の無声放電式レーザ。[Claims] 1. A silent discharge type in which an alternating current voltage is applied between a pair of electrodes, at least one of which is covered with a dielectric material, to generate a silent discharge in a discharge space sandwiched between the two electrodes. In the laser, the width and empty length of the discharge space in the cross section in the direction of the laser optical axis are made substantially equal, the discharge space and the optical resonance space are positioned so as to substantially overlap each other, and the gas medium is
It does not contain H 2 O and contains at least three types of gas components: CO 2 −N 2 −He, with a CO 2 molar fraction of 1 to 10%,
and a silent discharge laser characterized in that the molar fraction of N2 is in the range of 35 to 90%. 2 The gas medium does not contain H 2 O and contains at least CO 2 −
The silent discharge laser according to claim 1, characterized in that it contains four types of gas components: CO-N 2 -He. 3 The gas medium does not contain H 2 O and contains at least CO 2 −
The silent discharge laser according to claim 1 or 2, characterized in that it contains four types of gas components: N2- He -Ar.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23374689A JPH02132871A (en) | 1989-09-08 | 1989-09-08 | Silent discharge type laser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23374689A JPH02132871A (en) | 1989-09-08 | 1989-09-08 | Silent discharge type laser |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP55034593A Division JPS6035838B2 (en) | 1980-03-18 | 1980-03-18 | Silent discharge laser |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02132871A JPH02132871A (en) | 1990-05-22 |
| JPH0542839B2 true JPH0542839B2 (en) | 1993-06-29 |
Family
ID=16959930
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23374689A Granted JPH02132871A (en) | 1989-09-08 | 1989-09-08 | Silent discharge type laser |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02132871A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4979799A (en) * | 1972-11-15 | 1974-08-01 | ||
| JPS52115690A (en) * | 1976-03-24 | 1977-09-28 | Mitsubishi Electric Corp | Laser device |
| JPS53113496A (en) * | 1977-03-15 | 1978-10-03 | Mitsubishi Electric Corp | Gas laser device |
| JPS5424591A (en) * | 1977-07-26 | 1979-02-23 | Mitsubishi Electric Corp | Gas laser unit |
-
1989
- 1989-09-08 JP JP23374689A patent/JPH02132871A/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4979799A (en) * | 1972-11-15 | 1974-08-01 | ||
| JPS52115690A (en) * | 1976-03-24 | 1977-09-28 | Mitsubishi Electric Corp | Laser device |
| JPS53113496A (en) * | 1977-03-15 | 1978-10-03 | Mitsubishi Electric Corp | Gas laser device |
| JPS5424591A (en) * | 1977-07-26 | 1979-02-23 | Mitsubishi Electric Corp | Gas laser unit |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02132871A (en) | 1990-05-22 |
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