JP4261577B2 - Corona preionization electrode - Google Patents

Description

  The present invention relates to a discharge excitation type laser apparatus using ultraviolet light preionization by corona discharge, and more particularly to surface processing of a preionization electrode for performing preionization.

  A TEA laser forms an inversion distribution region necessary for laser oscillation by generating a uniform glow discharge in a gas of 1 atm or more existing in a main discharge space constituted by a pair of opposing main electrodes. This is a method for oscillation. In this TEA laser, in order to obtain a uniform glow discharge in the entire gas in the main discharge space, it is necessary to pre-ionize the entire gas in the main discharge space before starting the main discharge. In particular, in the case of an excimer laser, since the lifetime of electrons in the rare gas used for the main discharge is short, an inversion distribution is not formed unless excitation is performed within the lifetime, so as many as possible immediately before the main discharge. It is necessary to ionize the entire rare gas in the main discharge space. Currently, there are various types of preionization methods using X-ray, spark discharge, corona discharge, etc. Among them, the method using corona discharge is relatively simple and causes contamination of the gas in the main discharge space. Because of its small number, it is widely used as a capacity transfer type preionization method.

  FIG. 17 shows an equivalent circuit of a discharge circuit of an excimer laser device using a conventional preionization electrode, and FIG. 18 shows a conventional preionization electrode.

  The equivalent circuit of FIG. 17 includes a switch SW, capacitors Cs, Cp, Cp ′, coils Ls, Lp, Lc, a main electrode 1, and a preionization electrode 2.

  As shown in FIG. 18, the preliminary ionization electrode 2 includes a cylindrical rear electrode 3 inserted in a hollow portion of a cylindrical dielectric pipe 4, and an earth electrode having an L-shaped cross section on the outer peripheral surface of the dielectric pipe 4. 5 is in contact with the end.

  In the circuit of FIG. V. The capacitor Cs connected to is charged with charges through the coils Ls, Lp, and Lc.

  Next, the switch SW is turned on to move charges from the capacitor Cs to the capacitors Cp and Cp ′, thereby increasing the voltages of these Cp and Cp ′.

  When a high voltage is applied between the back electrode 3 and the ground electrode 5 and then the voltage of the capacitor Cp ′ reaches a predetermined corona discharge start voltage, the contact portion 6 between the ground electrode 5 and the dielectric pipe 4 is taken as a starting point. Corona discharge occurs on the outer peripheral surface of the dielectric pipe 4, and ultraviolet light is generated. This ultraviolet light preliminarily ionizes the laser gas in the main discharge space. Further, thereafter, the voltage of the capacitor Cp rises with the progress of charging, and when the voltage of this Cp reaches a predetermined main discharge start voltage, the preionized gas causes dielectric breakdown and the main discharge is started.

  In the conventional laser device, the ground electrode 5 of the preionization electrode 2 is configured separately from the dielectric pipe 4, and the ground electrode 5 is grounded so that the end of the ground electrode 5 is in contact with the surface of the dielectric pipe 4. Since the electrode 5 is provided, the dielectric pipe 4 is warped or bent, and a portion where a gap is generated in the contact portion 6 due to minute irregularities on the surface of the dielectric pipe 4 occurs. As a result, the dielectric pipe 4, the preionization intensity varies along the axial direction.

  That is, since corona discharge is generated starting from the contact portion between the dielectric 4 and the electrode 5, the light intensity of the ultraviolet light is weakened at the portion where the gap is generated. As a result, the ultraviolet light is emitted along the axial direction of the dielectric pipe 4. As a result, there is a distribution in the generation intensity of the light, and as a result, variations occur in the main discharge itself.

  Also, in the hollow portion of the dielectric pipe 4, a gap is generated due to the warp or bend of the dielectric pipe 4 described above, or minute irregularities on the inner peripheral surface of the dielectric pipe 4 and the surface of the back electrode 3. There is a problem in that power loss occurs due to unnecessary discharge generated in the gap portion, and the preionization intensity is reduced. Since the dielectric pipe 4 has a very small diameter of about 1 cm in diameter, it is almost impossible to eliminate the unevenness by polishing the surface (inner peripheral surface) of the hollow portion.

  Further, as described above, the corona discharge is generated starting from the contact portion 6 between the ground electrode 5 and the dielectric pipe 4, and this corona discharge thereafter spreads around the entire outer surface of the dielectric 4. However, ultraviolet light generated where the dielectric pipe 4 does not face the main electrode 1 does not contribute to preionization of the main discharge space. Here, in the case of corona discharge, a product is generated by discharge, and when this product enters the main discharge space when the main discharge is performed, it causes a reduction in laser output. However, in the conventional preionization electrode, since there is a discharge region that does not contribute to the preionization of the main discharge region on the outer peripheral surface of the dielectric pipe 4, a large amount of discharge products are generated and the laser output becomes unstable. There is a problem of doing.

  Furthermore, in the conventional corona preliminary ionization electrode, the outer peripheral surface of the dielectric pipe 4 that is the starting point of the corona discharge and the contact portion 6 of the ground electrode 5 are configured by only one straight line. The starting point (starting point) of the preliminary discharge cannot be secured at more point positions above. That is, in the above prior art, a sufficient distance from the starting point of the preliminary discharge cannot be ensured, so that the amount of ultraviolet light generated is small, so that sufficient preliminary ionization is not performed and a desired laser output cannot be obtained. There was a problem.

  As described above, the conventional preionization electrode has a problem that power loss due to unnecessary discharge occurs in each part, which causes a decrease in preionization intensity and a laser output. Further, the discharge that does not contribute to the preionization of the outer peripheral surface of the dielectric pipe 4 has a problem that a large amount of discharge products are generated and the laser output becomes unstable.

  The present invention has been made in view of the above circumstances, and by reducing power loss due to unnecessary discharge, the preionization intensity is increased, the laser output is increased, the generation of discharge products is reduced, and the output is stabilized. An object of the present invention is to provide a corona preionization electrode. Another object of the present invention is to provide a corona preionization electrode capable of obtaining the amount of ultraviolet light emission necessary for sufficient preionization over the entire main discharge space without increasing the size of the apparatus. .

  In the invention corresponding to claim 1, a hollow dielectric pipe, a back electrode disposed in a hollow portion of the dielectric pipe, and a corona electrode disposed so as to be in contact with an outer surface of the dielectric pipe And a preionizing electrode having a dielectric pipe on the side of the main discharge space so that the axis of the dielectric pipe extends along the longitudinal direction of the main discharge electrode, and applying a high voltage between the corona electrode and the back electrode. Thus, in the corona preionization electrode that generates a preionization in the main discharge space by generating a corona discharge starting from the contact portion between the corona electrode and the dielectric pipe, a metal is formed on the inner surface of the hollow part of the dielectric pipe. A rising layer is covered, and a metal layer is formed on the metalizing layer.

  According to a second aspect of the present invention, a hollow dielectric pipe, a back electrode disposed in a hollow portion of the dielectric pipe, and a corona electrode disposed so as to be in contact with the outer surface of the dielectric pipe are provided. A preionizing electrode having a side of the main discharge space with the axis of the dielectric pipe extending along the longitudinal direction of the main discharge electrode, and applying a high voltage between the corona electrode and the back electrode In a corona preionization electrode that generates a preionization in the main discharge space by generating a corona discharge starting from a contact part between a corona electrode and the dielectric pipe, the dielectric pipe and a hollow part of the dielectric pipe A conductor that contacts both the inner peripheral surface of the dielectric pipe and the outer peripheral surface of the back electrode is interposed between the rear electrode and the rear electrode.

  Examples of the conductor include a circular tube-shaped net body shown in claim 3, a spiral spring body shown in claim 4, a large number of needle-like bodies shown in claim 5.

  In the invention of claim 6, a hollow dielectric pipe, a back electrode disposed in a hollow portion of the dielectric pipe, and a corona electrode disposed so as to be in contact with the outer surface of the dielectric pipe. A preionizing electrode having a side of the main discharge space with the axis of the dielectric pipe extending along the longitudinal direction of the main discharge electrode, and applying a high voltage between the corona electrode and the back electrode In a corona preionization electrode that generates a preionization in the main discharge space by generating a corona discharge starting from a contact part between a corona electrode and the dielectric pipe, the dielectric pipe and a hollow part of the dielectric pipe A conductor powder is filled between the rear electrode disposed.

  According to a seventh aspect of the present invention, in the second to sixth aspects of the present invention, the dielectric pipe has a metal layer coated on the inner surface of the hollow portion.

  In the invention of claim 8, a hollow dielectric pipe, a back electrode disposed in a hollow portion of the dielectric pipe, and a corona electrode disposed so as to be in contact with the outer surface of the dielectric pipe. A preionizing electrode having a side of the main discharge space with the axis of the dielectric pipe extending along the longitudinal direction of the main discharge electrode, and applying a high voltage between the corona electrode and the back electrode In a corona preionization electrode that generates a preionization in the main discharge space by generating a corona discharge starting from a contact part between a corona electrode and the dielectric pipe, the dielectric pipe and a hollow part of the dielectric pipe An insulating powder is filled between the rear electrode and the rear electrode.

  In the invention of claim 9, a hollow dielectric pipe, a back electrode disposed in a hollow portion of the dielectric pipe, and a corona electrode disposed so as to be in contact with the outer surface of the dielectric pipe. A preionizing electrode having a side of the main discharge space with the axis of the dielectric pipe extending along the longitudinal direction of the main discharge electrode, and applying a high voltage between the corona electrode and the back electrode In a corona preionization electrode that generates a preionization in the main discharge space by generating a corona discharge starting from a contact part between a corona electrode and the dielectric pipe, the dielectric pipe and a hollow part of the dielectric pipe It is characterized in that a molten insulator is poured between the rear electrodes arranged and solidified.

  In a tenth aspect of the present invention, a hollow dielectric pipe, a back electrode disposed in a hollow portion of the dielectric pipe, and a corona electrode disposed so as to be in contact with the outer surface of the dielectric pipe are provided. A preionizing electrode having a side of the main discharge space with the axis of the dielectric pipe extending along the longitudinal direction of the main discharge electrode, and applying a high voltage between the corona electrode and the back electrode In a corona preionization electrode that generates preionization in the main discharge space by generating corona discharge starting from a contact portion between a corona electrode and the dielectric pipe, an Al rod is used as the back electrode, It is characterized in that Al2O3 is formed on the peripheral surface of the Al rod by surface oxidation treatment or CVD treatment, and the formed Al2O3 is used as a dielectric pipe.

  According to the first invention, the metallizing layer is coated on the inner surface of the hollow portion of the dielectric pipe and the metal layer is provided thereon, so that the adhesion strength between the dielectric pipe and the metal layer is enhanced. The loss of power on the hollow inner surface during corona discharge can be reduced, and the laser output can be increased by increasing the preionization intensity.

  According to the second to fifth inventions, the dielectric pipe and the back electrode disposed in the hollow portion of the dielectric pipe are in contact with both the inner peripheral surface of the dielectric pipe and the outer peripheral surface of the back electrode. As a result, the loss of power in the gap between the dielectric pipe and the back electrode during corona discharge can be reduced, and the preionization intensity is increased to increase the laser output. be able to.

  According to the sixth aspect of the present invention, since the conductor powder is filled in the gap between the dielectric pipe and the back electrode, the gap between these portions is eliminated, and power loss at that portion can be reduced. The laser output can be increased by increasing the preionization intensity.

  According to the seventh aspect, since the contact surfaces of the back electrode and the dielectric pipe are made of metal, the unnecessary power loss can be further reduced, and the preliminary ionization strength can be improved.

  According to the eighth invention, since the gap between the dielectric pipe and the back electrode is filled with the insulator powder, the gap between these portions is eliminated, and the loss of power at that portion can be reduced. At the same time, the laser output can be increased by increasing the preionization intensity.

  According to the ninth invention, since the molten insulator is poured between the dielectric pipe and the back electrode and solidified, the gap between these portions is eliminated, and the loss of power in that portion can be reduced. In addition, the pre-ionization intensity can be increased and the laser output can be increased.

  According to the tenth invention, an Al rod is used as the back electrode, and Al2O3 is formed on the peripheral surface of the Al rod by subjecting the Al rod to surface oxidation treatment or CVD treatment, and the formed Al2O3 is used as a dielectric pipe. As a result, the back electrode and the dielectric pipe can be configured integrally without any gaps, and the loss of power in these gaps can be reduced, and the preliminary ionization intensity is increased and the laser is increased. The output can be increased.

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

  FIG. 1 shows a first embodiment of the present invention.

  In the preionization electrode 2 shown in FIG. 1, a metal layer 7 is formed on the outer peripheral surface of the dielectric pipe 4 in which the back electrode 3 is inserted and is directed to the main discharge space. The outer electrode 8 is contacted. In this case, the external electrode 8 is grounded. The metal layer 7 is made of gold, nickel, or the like, and is formed in a strip shape along the longitudinal direction of the dielectric pipe 4 using a metallizing method such as a plating method, a vacuum deposition method, an ion plating method, or a thermal spraying method. . Examples of the material of the dielectric 4 include ceramics such as alumina ceramics, inorganic materials such as quartz glass, borosilicate glass, fluoride glass, and strontium titanate.

  That is, in this embodiment, the metallizing layer 7 coated on the surface of the dielectric pipe 4 is used as one electrode (in this case, a corona electrode) of the preionization electrode 2 and is brought into contact with the corona electrode layer 7. Electrical connection is made through the external electrode 8.

  In the preionization electrode 2 of FIG. 1, when a high voltage is applied between the back electrode 3 and the corona electrode 7, corona discharge is started at both end edges 7 a and 7 b of the corona electrode 7, and a corona is formed on the outer periphery of the dielectric pipe 4. As the discharge progresses, ultraviolet light is irradiated toward the main discharge space.

  According to the first embodiment, the corona electrode 7 is integrally formed on the dielectric pipe 4 by coating the outer peripheral surface of the dielectric pipe 4 with the metalizing method. There is no gap between the dielectric pipe 4 and the corona electrode 7, so that a pre-ionization intensity with a uniform distribution along the axial direction of the dielectric pipe 4 can be obtained, and variations in main discharge are also eliminated. be able to. Further, the laser output can be increased by increasing the preionization intensity.

  Even if there is a gap in the contact portion between the external electrode 8 and the corona electrode 7, these contact surfaces are made of metal with each other. Therefore, compared to the prior art in which one of the contact surfaces is a dielectric, In this case, power loss due to unnecessary discharge at the contact portion can be reduced.

  The external electrode 8 may be brought into contact with a part of the metalizing layer 7 covered in a strip shape along the axial direction of the dielectric pipe 4, and the shape thereof is that of the plate shown in FIG. Any one such as a wire or cable may be adopted.

  The shape of the back electrode 3 may be a polygonal column, and the shape of the dielectric pipe 4 may be a polygonal cylinder. Further, the back electrode 3 side may be grounded. Further, in the embodiment of FIG. 1, the surface of the dielectric 4 is first coated with a metallizing layer made of a material such as molybdenum or manganese, and a metal layer 7 such as gold or nickel is coated thereon, You may make it improve the adhesive strength of the metal layer 7 used as a corona electrode.

  FIG. 2 shows a second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the component same as FIG.

  In the second embodiment, a conductor layer 9 such as gold or nickel is formed by a metalizing method or the like in a region not facing the main discharge space in the outer peripheral surface region of the dielectric 4, and this metalizing layer 9 and the corona electrode 5 are in contact with each other. In this case, like the prior art shown in FIG. 12, the corona electrode 5 is configured as a separate body from the dielectric pipe 4 and is disposed so that the metalizing layer 9 and its end are in contact with each other. However, the corona electrode 5 may be omitted, an electric cable may be drawn from the metalizing layer 9 itself, and electrical connection may be performed using the electric cable.

  According to such a configuration, when a high voltage is applied between the back electrode 3 and the corona electrode 5, corona discharge is started at the edge portions 9 a and 9 b of the metalizing layer 9, and the metalizing layer of the dielectric pipe 4 is As the corona discharge is developed on the outer peripheral portion that is not formed, ultraviolet light is irradiated toward the main discharge space. According to the second embodiment, the idea is reversed from that of the prior art, the conductor layer 9 is formed in a region other than the region facing the main discharge space on the surface of the dielectric pipe 4, and the conductor layer 9 is corona. Since it is used as an electrode, it is possible to ensure the ultraviolet light toward the main discharge space, and at the same time, prevent unnecessary discharge in a region that does not contribute to preionization and generation of discharge products due to the discharge, thereby A stable laser output can be obtained, and power loss due to unnecessary discharge can be reduced.

  In the embodiment shown in FIG. 2, the surface of the dielectric 4 is first coated with a metalizing layer made of a material such as molybdenum or manganese, and a metal layer 9 such as gold or nickel is coated on the upper layer. You may make it improve the adhesive strength of the metal layer 9 used as a corona electrode.

  By the way, the length L in the direction perpendicular to the paper surface of the metalizing layers 7 and 9 in the embodiment shown in FIGS. 1 and 2 is the main discharge by the main electrode 1 as shown by hatching in FIG. Is set so as not to reach the insulator 10 that insulates and supports the preliminary ionization electrode at both ends, thereby generating a preliminary discharge over the entire main discharge space. .

  FIG. 4 shows a third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the component same as FIG.

  In the third embodiment, a metallizing layer 11 using a material such as molybdenum or manganese is first formed on the hollow inner surface of the dielectric pipe 4, and a metal plating layer 12 such as gold or nickel is further formed thereon. Try to form. That is, in this case, the back electrode 3 is inserted into the hollow portion of the dielectric 4 that has been subjected to metal plating.

  According to the third embodiment, even if a gap exists between the back electrode 3 and the inner peripheral surface of the hollow portion of the dielectric pipe 4, the contact surfaces of the back electrode 3 and the dielectric pipe 4 are made of metal with each other. Therefore, compared with the prior art in which one of the contact surfaces is a dielectric, unnecessary power loss in the hollow inner peripheral surface can be reduced during corona discharge, and the preliminary ionization strength can be improved.

  Furthermore, according to the third embodiment, since the metal plating layer 12 is formed via the metalizing layer 11, the adhesion strength of the metal plating layer 12 is enhanced, and the metal plating layer 12 is difficult to peel off. Become.

  In this case, the metal layer formed on the inner peripheral surface of the dielectric pipe 4 has a two-layer structure, but may have a one-layer structure.

  FIG. 5 shows a fourth embodiment of the present invention.

  The fourth embodiment shown in FIG. 5 is a modification of the embodiment shown in FIG. 1, and the shape of the corona electrode 7 formed on the outer peripheral surface of the dielectric pipe 4 is shown in FIG. As shown in Fig. 5, the preionization strength is enhanced by ensuring a larger distance between the start points of the corona discharge.

  In FIG. 5, the corona electrode 7 formed on the outer peripheral surface of the dielectric pipe 4 is formed only in a region facing the main discharge space between the pair of main electrodes 1 and is in contact with both ends thereof. Electrical connection is made through the external electrode 8 formed.

  In FIG. 5, when a high voltage is applied between the back electrode 3 and the corona electrode 7, a contact portion between the dielectric pipe 4 and the corona electrode 7, that is, one edge portion 7 c having a comb shape of the corona electrode and the other portion. Corona discharge is started at the edge 7d, and the corona discharge is developed around the outer periphery of the dielectric pipe 4, so that ultraviolet light is irradiated toward the main discharge space. According to this embodiment, since the edge portion 7c of the corona electrode has a comb shape, the length of the start point of the corona discharge is significantly longer than that of the conventional technology having a linear shape. It is possible to increase the amount of light emitted, whereby sufficient preionization can be performed over the entire main discharge space, and a desired laser output can be obtained without increasing the size of the apparatus. Further, since the corona electrode 7 is integrally formed on the dielectric pipe 4 by coating the outer peripheral surface of the dielectric pipe 4 with the metalizing method, the dielectric pipe 4 and the corona electrode 7 are formed. As a result, the preionization intensity having a uniform distribution along the axial direction of the dielectric pipe 4 can be obtained, and variations in main discharge can be eliminated. In addition, it is possible to increase the laser output by increasing the preionization intensity.

  Further, according to this embodiment, since the external electrode 8 is brought into contact with a part of the corona electrode 7, it is possible to avoid these poor contacts due to bending or warping of the dielectric pipe 4. Of course, as described above, the external electrode 8 may be an electric cable.

  In the embodiment shown in FIG. 5, one edge 7c of the corona electrode 7 has a comb shape, but the other edge 7d may also have a comb shape, which is the starting point of corona discharge. The length can be secured.

  The shape of the edge of the corona electrode 7 is not limited to the quadrangular shape shown in FIG. 5, but may be a polygon such as a triangle, a curved line, or a shape obtained by combining these. In short, the line connecting the edge of the contact portion from one end of the corona electrode to the other end may be longer than the axial length of the dielectric pipe.

  FIG. 6 shows a fifth embodiment of the present invention.

  In the fifth embodiment shown in FIG. 6, the embodiment shown in FIG. 5 and the embodiment shown in FIG. 2 are combined, and the surface of the dielectric pipe 4 other than the region facing the main discharge space is combined. A conductor layer is also formed in the region so as to prevent unnecessary discharge in the region that does not contribute to preionization and generation of discharge products due to the discharge.

  In FIG. 6, a region of the outer peripheral surface of the dielectric pipe 4 facing the main discharge space is left, a metalizing layer 15 is formed on the entire other surface, and this metalizing layer 15 is used as a corona electrode. By forming the end portion 15a of the metalizing layer 15 in a comb shape, more start points of corona discharge can be secured.

  In FIG. 6, when a high voltage is applied between the back electrode 3 and the corona electrode 15, corona discharge is started at one edge 15 a and the other edge 15 b of the corona electrode 15. As the corona discharge is developed around the outer periphery of the pipe 4, the ultraviolet light is irradiated toward the main discharge space. In the embodiment of FIG. 6, the other edge 15b of the corona electrode 15 may also be formed in a comb shape, and this can secure the start point length of the corona discharge. In the embodiment of FIG. 6, the corona electrode 15 is integrally formed on the outer periphery of the dielectric pipe 4 so as to ensure only one area where the dielectric 4 is open to the outside. An electrode disposed in a region facing the main discharge space on 4 and an electrode disposed in a region opposite to the main discharge space on the dielectric pipe 4 are formed on the dielectric pipe 4 as separate bodies. You may make it ensure two places where 4 was open | released outside.

  FIG. 7 shows a sixth embodiment of the present invention.

  In the sixth embodiment, the comb-shaped corona electrode 15 shown in FIG. 5 is replaced with at least two (in this case, three) wire electrodes 16.

  That is, a corona electrode formed on the outer peripheral surface of the dielectric pipe 4 is composed of at least two wire electrodes 16, and these wire electrodes 16 are formed in the main discharge space in the outer peripheral surface region of the dielectric pipe 4. It is arranged only in the area facing.

  In FIG. 7, when a high voltage is applied between the back electrode 3 and the wire electrode 16, corona discharge is started at each contact portion between the dielectric pipe 4 and each wire electrode 16, and corona discharge is generated on the outer periphery of the dielectric pipe 42. As a result of the development, ultraviolet light is irradiated toward the main discharge space.

  According to the sixth embodiment, the starting point of corona discharge is increased by an amount corresponding to the increase of the straight line of the contact portion from one to two as compared with the conventional corona preionization electrode. This makes it possible to increase the amount of light emitted from the main discharge space, so that sufficient preionization can be performed over the entire main discharge space, and a desired laser output can be obtained without increasing the size of the apparatus. In addition, since the corona electrode 16 is integrally formed on the dielectric pipe 4 by coating the outer peripheral surface of the dielectric pipe 4 with the metalizing method, the dielectric pipe 4 and the corona electrode 16 are formed. As a result, the preionization intensity having a uniform distribution along the axial direction of the dielectric pipe 4 can be obtained, and variations in main discharge can be eliminated. In addition, it is possible to increase the laser output by increasing the preionization intensity.

  FIG. 8 shows a seventh embodiment of the present invention.

  In the seventh embodiment, the embodiment shown in FIG. 7 and the embodiment shown in FIG. 2 are combined, and the corona electrode is composed of a plurality of wire electrodes 16 and the start point of the corona discharge is determined. The conductor layer 9 is formed in a region other than the region facing the main discharge space on the surface of the dielectric pipe 4 in addition to the length, and an unnecessary discharge in a region that does not contribute to preionization and a discharge product due to the discharge Is to prevent the occurrence of. The wire electrode 16 and the conductor layer 9 are formed by a metalizing method.

  In FIG. 8, when a high voltage is applied between the back electrode 3 and the wire electrode 16 (and the conductor layer 9), at each contact portion of the dielectric pipe 4 and each wire electrode 16 and at both ends 9 a and 9 b of the conductor layer 9. Corona discharge is started, and the corona discharge is developed around the outer periphery of the dielectric pipe 42, so that ultraviolet light is irradiated toward the main discharge space.

  FIG. 9 shows an eighth embodiment of the present invention.

  In the eighth embodiment, the comb-shaped corona electrode 15 shown in FIG. 5 is replaced with a mesh electrode 20 in which wires shown in FIG. 9B are crossed in a mesh shape. Yes.

  That is, the corona electrode formed by metallization on the outer peripheral surface of the dielectric pipe 4 is constituted by the mesh electrode 20, and the mesh electrode 20 faces the main discharge space in the outer peripheral surface region of the dielectric pipe 4. It is arranged only in the area. Since both end portions 21 of the mesh electrode 20 are in contact with the external electrode 8, a metalizing layer is formed on the entire surface.

  In FIG. 9, when a high voltage is applied between the back electrode 3 and the mesh electrode 20, corona discharge is started at each contact portion between the dielectric pipe 4 and the mesh electrode 20, and the outer periphery of the dielectric pipe 42 is As the corona discharge progresses, ultraviolet light is irradiated toward the main discharge space.

  According to the eighth embodiment, the starting point of the corona discharge is increased by the distance between the contact portion between the mesh electrode 20 and the dielectric pipe 4 that is longer than the conventional distance, and the amount of ultraviolet light emitted is correspondingly increased. Thus, sufficient preionization can be performed over the entire main discharge space, and a desired laser output can be obtained without increasing the size of the apparatus. Further, since the mesh electrode 20 is coated on the outer peripheral surface of the dielectric pipe 4 by the metalizing method, there is no gap between the dielectric pipe 4 and the mesh electrode 20, and thus the dielectric pipe Thus, a preionization intensity with a uniform distribution along the axial direction of 4 can be obtained, and variations in main discharge can be eliminated. In addition, it is possible to increase the laser output by increasing the preionization intensity.

  FIG. 10 shows a ninth embodiment of the present invention.

  In the ninth embodiment, the embodiment shown in FIG. 9 and the embodiment shown in FIG. 2 are combined, and the corona electrode is composed of the mesh electrode 20, and the length of the start point of the corona discharge is increased. In addition, the conductor layer 9 is formed in a region other than the region facing the main discharge space on the surface of the dielectric pipe 4, and unnecessary discharge in a region that does not contribute to preionization and discharge products generated by the discharge are formed. I try to prevent the occurrence. The wire electrode 16 and the conductor layer 9 are formed by a metalizing method.

  In FIG. 10, when a high voltage is applied between the back electrode 3 and the wire electrode 16 (and the conductor layer 9), each contact portion of the dielectric pipe 4 and each mesh electrode 20 and both end portions 9 a and 9 b of the conductor layer 9. , The corona discharge is started, and the corona discharge is developed around the outer periphery of the dielectric pipe 4 so that the ultraviolet light is irradiated toward the main discharge space.

  In each of the above embodiments, the metalizing layer is preferably gold or nickel as described above, but any other metal may be used as long as it is less corrosive to the laser gas.

  FIG. 11 shows a tenth embodiment of the present invention.

  In the tenth embodiment, as shown in FIG. 11 (d), a metallic mesh conductor 30 is interposed between the back electrode 3 and the dielectric pipe 4, so that the back electrode 3 and the dielectric pipe 4 are interposed. Is filled with a net-like metal, thereby reducing power loss due to unnecessary discharge in the gap between the back electrode 3 and the dielectric pipe 4 and improving the preionization strength. .

  As shown in FIG. 11 (a), the mesh conductor 30 is formed in a cylindrical shape like the outer conductor of the coaxial cable. First, the back electrode 3 is inserted into the mesh conductor 30. After that, the back electrode 3 with the mesh conductor 30 covered is inserted into the dielectric pipe 4 (FIGS. 11C and 11D).

  In this embodiment, the technique shown in FIG. 4 may be adopted. That is, if the mesh conductor 30 is interposed between the dielectric pipe 4 having a metal layer formed on its inner peripheral surface and the back electrode 3, the gap between the back electrode 3 and the dielectric pipe 4 is further increased. It is possible to reduce power loss due to unnecessary discharge in the gap.

  FIG. 12 shows an eleventh embodiment of the present invention.

  In the eleventh embodiment, a spiral spring 31 made of metal is interposed between the back electrode 3 and the dielectric pipe 4 so that the spiral spring 31 is placed on the outer peripheral surface of the back electrode and the inner peripheral surface of the dielectric pipe 4. Thus, the loss of electric power due to unnecessary discharge in the gap portion between the back electrode 3 and the dielectric pipe 4 is reduced, so that the preionization strength is improved.

  The spiral spring 31 is formed by spirally forming a flat plate having the same length as the axial length of the dielectric pipe 4.

  Also in this embodiment, the technique shown in FIG. 4 may be adopted. That is, if the spiral spring 31 is interposed between the dielectric pipe 4 having the metal layer formed on the inner peripheral surface thereof and the back electrode 3, the gap between the back electrode 3 and the dielectric pipe 4 is further increased. It is possible to reduce power loss due to unnecessary discharge at the portion.

  FIG. 13 shows a twelfth embodiment of the present invention.

  In the twelfth embodiment, by interposing a large number of metallic needles between the back electrode 3 and the dielectric pipe 4, the needles 32 are formed between the outer peripheral surface of the back electrode and the dielectric pipe 4. It is made to abut on both inner peripheral surfaces, thereby reducing power loss due to unnecessary discharge in the gap between the back electrode 3 and the dielectric pipe 4 and improving the preionization strength. .

  These many needle-like bodies 32 may be formed on the peripheral surface of the back electrode 3 so as to protrude from the peripheral surface of the back electrode 3, or may be formed on the inner peripheral surface of the dielectric pipe 4. It may be.

  Also in this embodiment, the technique shown in FIG. 4 may be adopted. That is, if the needle-like body 32 is interposed between the dielectric pipe 4 having the metal layer formed on the inner peripheral surface thereof and the back electrode 3, the gap between the back electrode 3 and the dielectric pipe 4 is further increased. It is possible to reduce power loss due to unnecessary discharge in the gap.

  FIG. 14 shows a thirteenth embodiment of the present invention.

  In the thirteenth embodiment, the gap between the back electrode 3 and the dielectric pipe 4 is filled with a powder 34 of a conductor such as Ni or Cu or a powder 34 of an insulator such as Al2 O3. The loss of electric power due to unnecessary discharge in the gap between the dielectric pipe 4 is reduced, and the preliminary ionization strength is improved.

  Also in this embodiment, the technique shown in FIG. 4 may be adopted. That is, if the conductor 34 or the insulator powder 34 is filled between the dielectric pipe 4 having a metal layer formed on the inner peripheral surface thereof and the back electrode 3, the back electrode 3 and the dielectric pipe 4 It is possible to reduce power loss due to unnecessary discharge in the gaps between the two.

  FIG. 15 shows a fourteenth embodiment of the present invention.

  In the fourteenth embodiment, a molten dielectric material (Ga or the like) is poured into the gap between the back electrode 3 and the dielectric pipe 4 and solidified to completely eliminate the gap. Thus, power loss due to unnecessary discharge in the gap portion can be reduced, and the preliminary ionization strength can be improved.

  FIG. 16 shows a fifteenth embodiment of the present invention.

  In this embodiment, instead of manufacturing the dielectric pipe 4 and the back electrode 3 as separate bodies and combining them later, the dielectric pipe 4 and the back electrode 3 are manufactured integrally.

  That is, an Al rod is used as the back electrode 3 and the Al rod is heated in a water vapor atmosphere to oxidize the surface of the Al rod, and this surface oxidation forms Al2O3 on the peripheral surface of the Al rod. The dielectric Al2O3 is used as the dielectric pipe 4.

  As described above, in this embodiment, since the dielectric 4 is formed on the back electrode 3 by surface oxidizing the Al rod, there is no gap between them, and unnecessary power is generated in these portions. Loss can be almost completely eliminated.

  Al2O3 may be attached to the surface of the Al rod using the CVD method.

  By the way, in the said embodiment, although this invention was applied to the excimer laser, as long as preliminary ionization is performed, you may make it apply this invention to other arbitrary gas lasers.

The figure which shows the 1st Embodiment of this invention. The figure which shows the 2nd Embodiment of this invention. The figure explaining the arrangement | positioning length of the metalizing layer in 1st and 2nd embodiment. The figure which shows the 3rd Embodiment of this invention. The figure which shows the 4th Embodiment of this invention. The figure which shows the 5th Embodiment of this invention. The figure which shows the 6th Embodiment of this invention. The figure which shows the 7th Embodiment of this invention. The figure which shows the 8th Embodiment of this invention. The figure which shows the 9th Embodiment of this invention. The figure which shows the 10th Embodiment of this invention. The figure which shows the 11th Embodiment of this invention. The figure which shows the 12th Embodiment of this invention. The figure which shows the 13th Embodiment of this invention. The figure which shows 14th Embodiment of this invention. The figure which shows 15th Embodiment of this invention. The figure which shows the equivalent circuit of the discharge circuit of the excimer laser apparatus using a preionization electrode. The figure which shows the conventional preliminary ionization electrode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main electrode 2 Pre-ionization electrode 3 Back electrode 4 Dielectric pipe 5 Corona electrode 7, 15 Corona electrode (metalizing layer)
8 External electrode 9 Corona electrode 10 Glass 11 Metallizing layer 12 Metal layer 15 Corona electrode 16 Corona electrode (wire electrode)
20 Corona electrode (mesh electrode)

Claims (10)

A preliminary ionization electrode having a hollow dielectric pipe, a back electrode disposed in a hollow portion of the dielectric pipe, and a corona electrode disposed so as to be in contact with an outer surface of the dielectric pipe is provided as the dielectric. The body pipe is disposed on the side of the main discharge space so that the axis of the main discharge electrode extends along the longitudinal direction of the main discharge electrode, and a high voltage is applied between the corona electrode and the back electrode to thereby provide the corona electrode and the dielectric pipe. In the corona preionization electrode that generates corona discharge starting from the contact portion with the main discharge space, a metalizing layer is coated on the inner surface of the hollow portion of the dielectric pipe. A corona preionization electrode characterized in that a metal layer is formed on the rising layer. A preliminary ionization electrode having a hollow dielectric pipe, a back electrode disposed in a hollow portion of the dielectric pipe, and a corona electrode disposed so as to be in contact with an outer surface of the dielectric pipe is provided as the dielectric. The body pipe is disposed on the side of the main discharge space so that the axis of the main discharge electrode extends along the longitudinal direction of the main discharge electrode, and a high voltage is applied between the corona electrode and the back electrode to thereby provide the corona electrode and the dielectric pipe. In the corona preionization electrode that generates corona discharge starting from the contact portion with the main discharge space, the dielectric pipe and the back electrode disposed in the hollow portion of the dielectric pipe A corona preionization electrode characterized in that a conductor contacting both the inner peripheral surface of the dielectric pipe and the outer peripheral surface of the back electrode is interposed between the first electrode and the second electrode. The corona preionization electrode according to claim 2, wherein the conductor is a tube-shaped network. The corona preionization electrode according to claim 2, wherein the conductor is a spiral spring whose axial length is substantially the same as the axial length of the dielectric pipe. The corona preionization electrode according to claim 2, wherein the conductor is a plurality of needle-like bodies protruding from the inner peripheral surface of the dielectric pipe or the outer peripheral surface of the back electrode. A preliminary ionization electrode having a hollow dielectric pipe, a back electrode disposed in a hollow portion of the dielectric pipe, and a corona electrode disposed so as to be in contact with an outer surface of the dielectric pipe is provided as the dielectric. The body pipe is disposed on the side of the main discharge space so that the axis of the main discharge electrode extends along the longitudinal direction of the main discharge electrode, and a high voltage is applied between the corona electrode and the back electrode to thereby provide the corona electrode and the dielectric pipe. In the corona preionization electrode that generates corona discharge starting from the contact portion with the main discharge space, the dielectric pipe and the back electrode disposed in the hollow portion of the dielectric pipe A corona preionization electrode characterized in that a conductor powder is filled in between. The corona preionization electrode according to claim 2, 3, 4, 5, or 6, wherein the dielectric pipe is formed by coating a metal layer on the inner surface of the hollow portion. A preliminary ionization electrode having a hollow dielectric pipe, a back electrode disposed in a hollow portion of the dielectric pipe, and a corona electrode disposed so as to be in contact with an outer surface of the dielectric pipe is provided as the dielectric. The body pipe is disposed on the side of the main discharge space so that the axis of the main discharge electrode extends along the longitudinal direction of the main discharge electrode, and a high voltage is applied between the corona electrode and the back electrode to thereby provide the corona electrode and the dielectric pipe. In the corona preionization electrode that generates corona discharge starting from the contact portion with the main discharge space, the dielectric pipe and the back electrode disposed in the hollow portion of the dielectric pipe A corona preionization electrode characterized in that an insulating powder is filled between the electrodes. A preliminary ionization electrode having a hollow dielectric pipe, a back electrode disposed in a hollow portion of the dielectric pipe, and a corona electrode disposed so as to be in contact with an outer surface of the dielectric pipe is provided as the dielectric. The body pipe is disposed on the side of the main discharge space so that the axis of the main discharge electrode extends along the longitudinal direction of the main discharge electrode. In the corona preionization electrode that generates corona discharge starting from the contact portion with the main discharge space, the dielectric pipe and the back electrode disposed in the hollow portion of the dielectric pipe A corona preionization electrode characterized in that a melted insulator is poured between and solidified. A preliminary ionization electrode having a hollow dielectric pipe, a back electrode disposed in a hollow portion of the dielectric pipe, and a corona electrode disposed so as to be in contact with an outer surface of the dielectric pipe is provided as the dielectric. The body pipe is disposed on the side of the main discharge space so that the axis of the main discharge electrode extends along the longitudinal direction of the main discharge electrode. In a corona preionization electrode that generates corona discharge starting from the contact portion with the main discharge space, an Al rod is used as the back electrode, and the Al rod is subjected to surface oxidation treatment or CVD treatment. A corona preionization electrode characterized in that Al2O3 is formed on the peripheral surface of the Al rod and the formed Al2O3 is used as a dielectric pipe.

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