JP2024158398A - Luminous envelope - Google Patents

Abstract

To provide a light-emission sealed body that can achieve both improvement of the quality of output light and improvement of the output of the output light.SOLUTION: A light-emission sealed body 1A includes an accommodation structure 2 that accommodates gas G for generating plasma. The accommodation structure 2 includes a laser light incidence window part 20A to make laser light L1, which keeps plasma in a plasma region R where plasma is generated, enter the plasma region R, a plasma light emission window part 20B that makes plasma light L2, which is generated from the plasma, exit from the plasma region R, a laser light passage window part 20D that opposes the laser light incidence window part 20A with the plasma region R therebetween and makes the laser light L1, which has transmitted through the plasma, exit from the plasma region R, and a wall part 80a with a light-blocking property that defines a light passage region in at least the laser light passage window part 20D.SELECTED DRAWING: Figure 1

Description

The present invention relates to a light-emitting envelope that is applied, for example, to a laser excitation light source.

A light-emitting envelope that is applied to a laser excitation light source is known that has a housing that contains a gas for generating plasma, and the housing has a laser light entrance window that allows laser light to enter a plasma region to maintain the plasma, and a plasma light exit window that allows plasma light emitted from the plasma to exit the plasma region, with the plasma light exit window facing the laser light entrance window across the plasma region (see, for example, Patent Document 1).

U.S. Pat. No. 1,000,8378

In the light-emitting envelope described above, there is a high possibility that the laser light that has passed through the plasma will be emitted from the plasma light emission window together with the plasma light. In that case, the output light will be a mixture of plasma light and laser light, and the quality of the output light will be reduced. In addition, since the laser light emitted from the plasma light emission window enters an optical system for using the plasma light, if the output of the laser light is increased to increase the light emission output, the laser light with increased output may have adverse effects such as heat on the optical system. In response to this, it is possible to configure the light-emitting envelope so that the laser light is not emitted outside the envelope in the first place. For example, it is possible to place a light-shielding member or a light-absorbing member in a position facing the laser light entrance window. However, even in this case, if the output of the laser light is increased, the effect of heat inside the light-emitting envelope will increase, and the light-emitting envelope and internal components may be damaged.

The present invention aims to provide a light-emitting envelope that can improve both the quality of the output light and the output of the output light.

The luminous envelope of the present invention is a luminous envelope that includes a storage structure that stores a gas for generating plasma, the storage structure having a first window that allows a first light for maintaining the plasma in a plasma region where the plasma is generated to enter the plasma region, a second window that allows a second light emitted from the plasma to exit the plasma region, a third window that faces the first window across the plasma region and allows the first light that has passed through the plasma to exit the plasma region, and a wall that has light-shielding properties and defines at least a light-passing region of the third window.

In the light-emitting envelope described in [1] above, the storage structure that stores the gas for generating plasma has a third window that allows the first light that has passed through the plasma to exit the plasma region. This third window is a window that is different from the second window that allows the second light emitted from the plasma to exit the plasma region, and faces the first window that allows the first light to enter the plasma region, sandwiching the plasma region. This allows the second light to be extracted as output light from the second window, while the first light that has passed through the plasma to be extracted to the outside of the light-emitting envelope from the third window. Therefore, even if the output of the first light is increased, the influence of the first light in the light-emitting envelope can be suppressed while suppressing the first light from being mixed into the output light. Therefore, according to the light-emitting envelope described in [1] above, it is possible to achieve both an improvement in the quality of the output light and an improvement in the output light output.

The luminous envelope of the present invention may be [2] "the luminous envelope described in [1] above, in which the third window also emits the second light emitted from the plasma region to the third window." According to the luminous envelope described in [2], in addition to the first light transmitted through the plasma, the second light emitted from the plasma region to the third window is also extracted from the third window, thereby suppressing the influence of the second light within the luminous envelope and achieving both an improvement in the quality of the output light and an improvement in the output power of the output light.

The luminous envelope of the present invention may be [3] "the luminous envelope described in [1] or [2] above, in which the storage structure has a housing having the first window portion and the second window portion, and an enclosure portion having the third window portion and the wall portion and defining an enclosed space including the plasma region within the housing." According to the luminous envelope described in [3], the space through which the gas convects is narrower than when the storage structure does not have an enclosure portion, so that it is possible to reliably suppress the occurrence of gas convection in the space. As a result, noise components can be removed from the output light, and the quality of the output light can be improved.

The luminous envelope of the present invention may be the luminous envelope described in [4] above, in which "the enclosure has a first opening corresponding to the first window and a second opening corresponding to the second window, the first window is located on the opposite side of the enclosed space from the opening end of the first opening on the enclosed space side, the second window is located on the opposite side of the enclosed space from the opening end of the second opening on the enclosed space side, and at least one of the first opening and the second opening is narrowed with respect to the enclosed space." According to the luminous envelope described in [4], it is possible to more reliably suppress the occurrence of convection in the gas. Therefore, it is possible to improve the quality of the output light.

The luminous envelope of the present invention may be the luminous envelope described in [3] above, further comprising: [5] "a first electrode having a first tip facing the plasma region in the housing; a second electrode having a second tip facing the plasma region in the housing and facing the first tip across the plasma region; and an insulating first holding part that holds the first electrode and is fixed to the housing, the enclosure surrounding the plasma region, the first tip and the second tip in the housing, an insulating enclosure having a first opening corresponding to the first window and a second opening corresponding to the second window, and at least a part of the enclosure being provided in the first holding part." According to the luminous envelope described in [5], at least a part of the enclosure can be formed by using the first holding part that holds the first electrode. In addition, since the first tip of the first electrode and the second tip of the second electrode are surrounded by an insulating surrounding portion, even if the surrounding space is narrow, plasma can be reliably generated and the plasma can be stably maintained. Therefore, the quality of the output light can be improved.

The luminous envelope of the present invention may be the luminous envelope described in [5] above, [6] "further comprising an insulating second holding part that holds the second electrode and is fixed to the housing, the surrounding part having a first surrounding part and a second surrounding part, the first surrounding part being provided on the first holding part as a part thereof, and the second surrounding part being provided on the second holding part." According to the luminous envelope described in [6], the surrounding part can be easily configured by utilizing the first holding part that holds the first electrode and the second holding part that holds the second electrode.

The luminous envelope of the present invention may be [7] "the luminous envelope according to any one of [3] to [6] above, in which the casing further has a fourth window portion facing the third window portion, and the fourth window portion causes the first light transmitted through the third window portion to be emitted outside the casing." According to the luminous envelope according to [7], the first light that is incident on a space in which a gas is present and that has transmitted through the plasma can be emitted outside the casing through the third window portion of the surrounding portion and the fourth window portion of the casing.

The luminous envelope of the present invention may be the luminous envelope described in [8] above, in which "each of the first window portion, the second window portion, the third window portion, and the fourth window portion has a window member, and the distance between the window member of the third window portion and the plasma region is smaller than any of the distance between the window member of the first window portion and the plasma region, the distance between the window member of the second window portion and the plasma region, and the distance between the window member of the fourth window portion and the plasma region." According to the luminous envelope described in [8], the space through which the gas convects is narrower than when the enclosure does not have the third window portion, so that the occurrence of gas convection in the space can be reliably suppressed. As a result, noise components can be removed from the output light, and the quality of the output light can be improved.

The luminous envelope of the present invention may be [9] "the luminous envelope described in [8] above, in which the thickness of the window member of the third window portion is smaller than the thickness of the window member of the fourth window portion." According to the luminous envelope described in [9], the window member of the third window portion, which is closer to the plasma than the other window members and therefore more susceptible to the thermal effect of the plasma, can be made thinner to reduce the effects of thermal expansion and the like, and damage to the window member of the third window portion and changes in the fixed state can be suppressed. Therefore, the luminous envelope can be operated stably, and the quality of the output light can be improved.

The luminous envelope of the present invention may be [10] "the luminous envelope described in [1] or [2] above, in which the storage structure has a housing having the first window, the second window, the third window, and the wall, and the housing defines an enclosed space including the plasma region." With the luminous envelope described in [10], the first light that is incident on a space in which a gas is present and that has passed through the plasma can be emitted to the outside of the housing through the third window of the housing with a simpler configuration.

The present invention makes it possible to provide a light-emitting envelope that can achieve both improved quality of output light and improved output of output light.

FIG. 2 is a cross-sectional view of the luminous envelope of the first embodiment. 2 is a cross-sectional view of the luminous envelope taken along line II-II shown in FIG. 1. 3 is a cross-sectional view of the luminous envelope taken along line III-III shown in FIG. 1. FIG. 6 is a cross-sectional view of a luminous envelope according to a second embodiment. 5 is a cross-sectional view of the light-emitting envelope taken along line VV shown in FIG. 4. 6 is a cross-sectional view of the luminous envelope taken along line VI-VI shown in FIG. 4. FIG. 11 is a cross-sectional view of a luminous envelope according to a third embodiment. 8 is a cross-sectional view of the luminous envelope taken along line VIII-VIII shown in FIG. 7. 9 is a cross-sectional view of the luminous envelope taken along line IX-IX shown in FIG. 7.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations will be omitted.
[First embodiment]

As shown in Figures 1, 2 and 3, the light-emitting envelope 1A of the first embodiment includes a storage structure 2, a first electrode 3, a second electrode 4 and a first holding part 5. The storage structure 2 has a housing 7 and an enclosure 8. The storage structure 2 stores gas G for generating plasma. The gas G is, for example, xenon gas. In the light-emitting envelope 1A, a laser light (first light) L1 for maintaining plasma is incident on a plasma region R (a region where plasma is generated in the gas G), and plasma light (second light) L2 emitted from the plasma is emitted from the plasma region R. Note that the plasma light L2 emitted from the plasma is actually generated radiatively in all directions from the plasma region R, but for convenience, only the plasma light L2 as output light is illustrated. The wavelength of the laser light L1 is, for example, about 800 nm to 1100 nm, and the wavelength of the plasma light L2 is, for example, about 120 nm to 20 μm. The light-emitting envelope 1A is a device that is applied to a laser excitation light source.

The housing 7 has a main body 70, a laser light entrance window (first window) 20A, a plasma light exit window (second window) 20B, and a laser light exit window (fourth window) 20C. The main body 70 has a storage space 71, three window openings 72, 73, 74, and two electrode openings 75, 76. The storage space 71 includes a plasma region R. The window opening 72 opens from the storage space 71 to one side in the Z-axis direction. The window opening 74 opens from the storage space 71 to the other side in the Z-axis direction. The window opening 73 opens from the storage space 71 to one side in the X-axis direction (direction perpendicular to the Z-axis direction). The electrode opening 75 opens from the storage space 71 to one side in the Y-axis direction (direction perpendicular to both the Z-axis direction and the X-axis direction). The electrode opening 76 opens from the storage space 71 to the other side in the Y-axis direction. The material of the main body 70 is a metal material such as stainless steel.

The laser light entrance window 20A hermetically seals the window opening 72. The laser light entrance window 20A allows the laser light L1 to enter the plasma region R. In the light-emitting envelope 1A, the laser light entrance window 20A allows the laser light L1 to enter the plasma region R along an optical axis A1 that is parallel to the Z-axis direction. In other words, the optical axis of the laser light L1 is the optical axis A1.

The laser light entrance window 20A has a window member 21 and a holding member 22. The window member 21 is formed in a plate shape with the optical axis A1 as the center line and the Z-axis direction as the thickness direction. The window member 21 transmits the laser light L1. The material of the window member 21 is a light-transmitting material that is transparent at least with respect to the wavelength of the laser light L1, such as sapphire. The holding member 22 is formed in a cylindrical shape with the optical axis A1 as the center line. The window member 21 is held by the holding member 22 while being placed inside the holding member 22. The material of the holding member 22 is a metal material such as Kovar. The side of the window member 21 is hermetically joined to the inner surface of the holding member 22 by a joining material such as a metal brazing material. The outer surface of the holding member 22 is hermetically joined to the inner surface of the window opening 72 by, for example, laser welding.

The plasma light emission window 20B airtightly seals the window opening 73. The plasma light emission window 20B is disposed at a position other than the position facing the laser light entrance window 20A across the plasma region R. In other words, the plasma light emission window 20B does not face the laser light entrance window 20A across the plasma region R. The plasma light emission window 20B emits the plasma light L2 from the plasma region R. In the light-emitting envelope 1A, the plasma light emission window 20B emits the plasma light L2 from the plasma region R along the optical axis A2 parallel to the X-axis direction. In other words, the optical axis of the plasma light L2 is the optical axis A2. The optical axis A1 and the optical axis A2 intersect at the center of the plasma region R, and in this embodiment, they intersect perpendicularly.

The plasma light emission window 20B has a window member 23 and a holding member 24. The window member 23 is formed in a plate shape with the optical axis A2 as the center line and the X-axis direction as the thickness direction. The window member 23 transmits the plasma light L2. The material of the window member 23 is a light-transmitting material that is transparent at least for the wavelength of the plasma light L2, such as diamond, sapphire, or magnesium fluoride. The holding member 24 is formed in a cylindrical shape with the optical axis A2 as the center line. The window member 23 is held by the holding member 24 while being placed inside the holding member 24. The material of the holding member 24 is a metal material such as Kovar. The side of the window member 23 is hermetically joined to the inner surface of the holding member 24 by a joining material such as a metal brazing material. The outer surface of the holding member 24 is hermetically joined to the inner surface of the window opening 73 by, for example, laser welding.

The laser light emission window 20C hermetically seals the window opening 74. The laser light emission window 20C emits the laser light L1 that has passed through the plasma from the plasma region R. In this embodiment, the laser light emission window 20C emits the plasma light L2 emitted from the plasma region R to the laser light emission window 20C side in addition to the laser light L1 that has passed through the plasma, but the plasma light L2 is not shown in the figure to simplify the drawing. The optical axis of the plasma light L2 emitted from the laser light emission window 20C is coaxial with the laser light L1. In the light-emitting envelope 1A, the laser light emission window 20C emits the laser light L1 from the plasma region R along the optical axis A1. In other words, the emitted light emitted from the laser light emission window 20C has an optical axis that is coaxial with the optical axis A1 of the laser light L1.

The laser light emission window portion 20C has a window member 25 and a holding member 26. The window member 25 is formed in a plate shape with the optical axis A1 as the center line and the Z-axis direction as the thickness direction. The window member 25 transmits the laser light L1. The material of the window member 25 is a light-transmitting material that is transparent at least with respect to the wavelength of the laser light L1, and more preferably is a light-transmitting material that is transparent with respect to the wavelength of the plasma light L2 in addition to the wavelength of the laser light L1. In this embodiment, the material of the window member 25 is a material that is transparent with respect to both the wavelength of the laser light L1 and the wavelength of the plasma light L2, such as sapphire. The holding member 26 is formed in a cylindrical shape with the optical axis A1 as the center line. The window member 25 is held by the holding member 26 while being arranged inside the holding member 26. The material of the holding member 26 is, for example, a metal material such as Kovar. The side of the window member 25 is hermetically joined to the inner surface of the holding member 26 by a joining material such as a metal brazing material. The outer surface of the holding member 26 is hermetically joined to the inner surface of the window opening 74 by, for example, laser welding.

The surrounding portion 8 is disposed in the storage space 71 of the housing 7. The surrounding portion 8 has an insulating main body portion 80 and an insulating laser light passing window portion (third window portion) 20D. The main body portion 80 has an enclosed space 81, three light passing openings 82, 83, 84, and two electrode openings 85, 86. The enclosed space 81 includes a plasma region R. The light passing opening 82 opens from the enclosed space 81 to one side in the Z-axis direction. The light passing opening 84 opens from the enclosed space 81 to the other side in the Z-axis direction. The light passing opening 83 opens from the enclosed space 81 to one side in the X-axis direction. The electrode opening 85 opens from the enclosed space 81 to one side in the Y-axis direction. The electrode opening 86 opens from the enclosed space 81 to the other side in the Y-axis direction. The diameters of the electrode openings 85 and 86 are slightly larger than the diameters of the first electrode 3 and the second electrode 4, respectively. The main body 80 is separated from the first electrode 3 and the second electrode 4 by a small gap. The length of the gap is 1/5 or less of the diameter of the first electrode 3 and the second electrode 4. Therefore, the influence of thermal expansion of each member and variations in the accuracy and positioning of the members can be suppressed without significantly affecting the movement of the gas (generation of convection) in the enclosed space 81. The enclosed space 81 is surrounded by the wall of the main body 80, the three light passing openings 82, 83, and 84, and the two electrode openings 85 and 86 in the storage space 71. In other words, the enclosure 8 defines the enclosed space 81 in the housing 7 and surrounds the plasma region R in the housing 7.

The light passing opening (first opening) 82 corresponds to the laser light entrance window 20A. That is, when viewed from the direction in which the plasma region R and the laser light entrance window 20A are lined up (the Z-axis direction in the light-emitting envelope 1A), the light passing opening 82 overlaps with the laser light entrance window 20A. In the light-emitting envelope 1A, the center line of the light passing opening 82 coincides with the center line of the window member 21 of the laser light entrance window 20A (that is, coincides with the optical axis A1), and the light passing opening 82 is included in the window member 21 of the laser light entrance window 20A when viewed from the Z-axis direction. The light passing opening 82 is narrowed with respect to the enclosed space 81. That is, when viewed from the direction in which the plasma region R and the light passing opening 82 are lined up (the Z-axis direction in the light-emitting envelope 1A), the opening end 82a on the enclosed space 81 side of the light passing opening 82 is included in the enclosed space 81. In the light-emitting envelope 1A, the light-passing opening 82 is a tapered opening in which the opening end 82a on the enclosed space 81 side is smaller than the opening end 82b on the opposite side to the enclosed space 81. The window member 21 of the laser light entrance window portion 20A is located outside the light-passing opening 82.

The light passage opening (second opening) 83 corresponds to the plasma light exit window 20B. That is, when viewed from the direction in which the plasma region R and the plasma light exit window 20B are lined up (the X-axis direction in the light-emitting envelope 1A), the light passage opening 83 overlaps with the plasma light exit window 20B. In the light-emitting envelope 1A, the center line of the light passage opening 83 coincides with the center line of the window member 23 of the plasma light exit window 20B (i.e., coincides with the optical axis A2), and the light passage opening 83 is included in the window member 23 of the plasma light exit window 20B when viewed from the X-axis direction. The light passage opening 83 is narrowed with respect to the enclosed space 81. That is, when viewed from the direction in which the plasma region R and the light passage opening 83 are lined up (the X-axis direction in the light-emitting envelope 1A), the opening end 83a of the light passage opening 83 on the enclosed space 81 side is included in the enclosed space 81. In the light-emitting envelope 1A, the light passing opening 83 is a tapered opening in which the opening end 83a on the enclosed space 81 side is smaller than the opening end 83b on the opposite side to the enclosed space 81. The window member 23 of the plasma light exit window portion 20B is located outside the light passing opening 83.

The light passing opening 84 corresponds to the laser light emitting window 20C. That is, when viewed from the direction in which the plasma region R and the laser light emitting window 20C are lined up (the Z-axis direction in the light emitting envelope 1A), the light passing opening 84 overlaps with the laser light emitting window 20C. In the light emitting envelope 1A, the center line of the light passing opening 84 coincides with the center line of the window member 25 of the laser light emitting window 20C (that is, coincides with the optical axis A1), and the light passing opening 84 is included in the window member 25 of the laser light emitting window 20C when viewed from the Z-axis direction. The light passing opening 84 is narrowed with respect to the enclosed space 81. That is, when viewed from the direction in which the plasma region R and the light passing opening 84 are lined up (the Z-axis direction in the light emitting envelope 1A), the opening end 84a on the enclosed space 81 side of the light passing opening 84 is included in the enclosed space 81. In the light-emitting envelope 1A, the light passing opening 84 is a stepped opening in which the opening end 84a on the enclosed space 81 side is smaller than the opening end 84b on the opposite side to the enclosed space 81. The window member 25 of the laser light exit window portion 20C is located outside the light passing opening 84.

The laser light passing window 20D is disposed in the light passing opening 84. The laser light passing window 20D faces the laser light exit window 20C and faces the laser light entrance window 20A across the plasma region R. The laser light passing window 20D emits the laser light L1 that has passed through the plasma from the plasma region R. In this embodiment, the laser light passing window 20D emits the plasma light L2 emitted from the plasma region R to the laser light passing window 20D side in addition to the laser light L1 that has passed through the plasma, but the plasma light L2 is not shown in order to simplify the drawing. The optical axis of the plasma light L2 emitted from the laser light passing window 20D is coaxial with the laser light L1. In the light-emitting envelope 1A, the laser light passing window 20D emits the laser light L1 from the plasma region R along the optical axis A1. In other words, the light emitted from the laser light passing window 20D has an optical axis coaxial with the optical axis A1 of the laser light L1. The laser light passing window 20D has an insulating window member 27. The window member 27 is formed in a plate shape with the optical axis A1 as the center line and the Z-axis direction as the thickness direction. The distance between the window member 27 of the laser light passing window 20D and the plasma region R is smaller than the distance between the window member 21 of the laser light entrance window 20A and the plasma region R, the distance between the window member 23 of the plasma light exit window 20B and the plasma region R, and the distance between the window member 25 of the laser light exit window 20C and the plasma region R. The thickness of the window member 27 is smaller than the thicknesses of the other window members 21, 23, and 25. The window member 27 transmits the laser light L1. The material of the window member 27 is a light-transmitting material that is transparent at least to the wavelength of the laser light L1, and more preferably to the wavelength of the plasma light L2 in addition to the wavelength of the laser light L1. In this embodiment, the material of the window member 27 is a material that is transparent to both the wavelength of the laser light L1 and the wavelength of the plasma light L2, such as sapphire. The light passing region (the region through which the laser light L1 passes) of the laser light passing window 20D is defined by the wall 80a of the main body 80 having light-shielding properties. In the light-emitting envelope 1A, the light passing region of the window member 27 is defined by the wall 80a. In other words, when viewed from the direction in which the plasma region R and the light passing opening 84 are aligned (the Z-axis direction in the light-emitting envelope 1A), the light passing region of the window member 27 is surrounded by the wall 80a.

The wall portion 80a is positioned so that the laser light L1 that has passed through the plasma is not irradiated thereto. In other words, the laser light passing window portion 20D is provided so that the laser light L1 that has passed through the plasma is irradiated only to the light passing region of the window member 27 defined by the wall portion 80a and passes only through the light passing region. This prevents the laser light L1 that has passed through the plasma from being irradiated to the fixed region between the wall portion 80a and the window member 27, and prevents the fixed state between the wall portion 80a and the window member 27 from changing due to the influence of heat, etc.

In the light-emitting envelope 1A, the main body 80 has a first surrounding member 80A, a second surrounding member 80B, and a third surrounding member 80C. The first surrounding member 80A defines most of the enclosed space 81, a light passage opening 83, a part of the enclosed space 81 side of the light passage opening 84, and two electrode openings 85, 86. The second surrounding member 80B defines the light passage opening 82 and a part of the enclosed space 81 side of the light passage opening 82. The third surrounding member 80C defines most of the light passage opening 84. The materials of the first surrounding member 80A, the second surrounding member 80B, and the third surrounding member 80C are insulating materials having high temperature resistance, such as ceramics. In particular, when white ceramics are used, the amount of light extracted from the plasma light emission window portion 20B can be increased by reflecting the plasma light L2. The window member 25 is sandwiched between the first surrounding member 80A and the third surrounding member 80C. The first surrounding member 80A, the second surrounding member 80B, and the third surrounding member 80C are held by the housing 7 in a state where they are combined together with the window member 25.

The first electrode 3 extends from outside the housing 7 into the enclosed space 81 through the electrode opening 75 of the housing 7 and the electrode opening 85 of the enclosure 8. In the luminous envelope 1A, the first electrode 3 is a rod-shaped member extending in the Y-axis direction. The material of the first electrode 3 is a high-melting point metal material such as tungsten. The tip portion (first tip portion) 31 of the first electrode 3 faces the plasma region R in the housing 7. In the luminous envelope 1A, the tip portion 31 of the first electrode 3 faces the plasma region R in the enclosed space 81 and is enclosed by the enclosure 8.

The first holding portion 5 is an insulating member and holds the first electrode 3. The material of the first holding portion 5 is an insulating material having high temperature resistance, such as ceramic. In the luminous envelope 1A, the first holding portion 5 has a main body portion 51 and a pair of cylindrical portions 52, 53. The cylindrical portion 52 is located on the opposite side of the plasma region R with respect to the main body portion 51, and the cylindrical portion 53 is located on the plasma region R side with respect to the main body portion 51. The main body portion 51 and the cylindrical portion 52 are arranged outside the electrode opening 75 of the housing 7, and the cylindrical portion 53 is arranged inside the electrode opening 75 of the housing 7. A through hole 51a is formed in the main body portion 51. The through hole 51a extends in the Y-axis direction and opens to the inside of each cylindrical portion 52, 53. The middle portion 32 of the first electrode 3 is arranged in the through hole 51a. The side of the intermediate portion 32 is hermetically joined to the inner surface of the through hole 51a by a joining material such as a metal brazing material. The base end portion 33 of the first electrode 3 is disposed inside the cylindrical portion 52.

The first holding part 5 is fixed to the housing 7. In the luminous envelope 1A, the first holding part 5 is fixed to the housing 7 via a cylindrical connecting member 9. The connecting member 9 has a cylindrical part 91 and an inward flange part 92. The inward flange part 92 is provided at the end of the cylindrical part 91 opposite the housing 7. The material of the connecting member 9 is a metal material such as Kovar. The inward flange part 92 is hermetically joined to the outward flange part 54 provided on the main body part 51 of the first holding part 5 by a joining material such as a metal brazing material. The end of the cylindrical part 91 on the housing 7 side is hermetically joined to the housing 7 by, for example, laser welding.

The second electrode 4 extends from the electrode opening 76 of the housing 7 into the enclosed space 81 through the electrode opening 86 of the enclosure 8. In the luminous envelope 1A, the second electrode 4 is a rod-shaped member extending in the Y-axis direction. The material of the second electrode 4 is a high-melting point metal material such as tungsten. The tip (second tip) 41 of the second electrode 4 faces the plasma region R in the housing 7 and faces the tip 31 of the first electrode 3 across the plasma region R. In the luminous envelope 1A, the tip 41 of the second electrode 4 faces the plasma region R in the enclosed space 81 and is enclosed by the enclosure 8. The side of the base end 43 of the second electrode 4 is hermetically joined to the inner surface of the electrode opening 76 by a joining material such as a metal brazing material.

The main body 70 of the housing 7 has an inlet hole 77 for injecting gas G into the storage space 71. The inlet tube 12 is connected to the inlet hole 77. The material of the inlet tube 12 is a metal material such as copper. The end of the inlet tube 12 opposite the inlet hole 77 is sealed. The outer surface of the inlet tube 12 is hermetically joined to the inner surface of the inlet hole 77 by a joining material such as a metal brazing material.

In the light-emitting envelope 1A configured as described above, the second electrode 4 is set to ground potential, and a negative voltage pulse or a positive voltage pulse is applied to the first electrode 3. This causes an arc discharge in the gas G in the enclosed space 81, and plasma is generated between the first electrode 3 and the second electrode 4. At this time, the laser light L1 is incident on the plasma region R from the laser light entrance window 20A, thereby maintaining the plasma in the plasma region R. Then, the plasma light L2 emitted from the plasma is emitted to the outside as output light from the plasma light exit window 20B.

As described above, in the light-emitting envelope 1A, the containing structure 2 containing the gas G for generating plasma has a laser light passing window 20D that emits the laser light L1 that has passed through the plasma from the plasma region R. This laser light passing window 20D is a window different from the plasma light emitting window 20B that emits the plasma light L2 emitted from the plasma from the plasma region R, and faces the laser light incident window 20A that makes the laser light L1 enter the plasma region R across the plasma region R. This makes it possible to extract the plasma light L2 as output light from the plasma light emitting window 20B, while extracting the laser light L1 that has passed through the plasma from the laser light passing window 20D to the outside of the light-emitting envelope 1A. Therefore, even if the output of the laser light L1 is increased, the influence of the laser light L1 in the light-emitting envelope 1A can be suppressed while suppressing the mixing of the laser light L1 with the output light. Therefore, according to the light-emitting envelope 1A, it is possible to achieve both an improvement in the quality of the output light and an improvement in the output light output.

In the light-emitting envelope 1A, the laser light passing window 20D also emits plasma light L2 emitted from the plasma region R to the laser light passing window 20D side. In this way, in addition to the laser light L1 that has passed through the plasma, the plasma light L2 emitted from the plasma region R to the laser light passing window 20D side is also extracted from the laser light passing window 20D, thereby suppressing the influence of the plasma light L2 within the light-emitting envelope 1A and achieving both improved quality of the output light and improved power of the output light.

In the light-emitting envelope 1A, the storage structure 2 has a housing 7 having a laser light entrance window 20A and a plasma light exit window 20B, and an enclosure 8 having a laser light passage window 20D and a wall 80a, defining an enclosed space 81 including a plasma region R within the housing 7. As a result, the space in which the gas G convects is narrower than when the storage structure 2 does not have the enclosure 8, and it is possible to reliably suppress the occurrence of convection in the gas G in the space. As a result, noise components can be removed from the output light, improving the quality of the output light.

In the light-emitting envelope 1A, the laser light entrance window 20A is located on the opposite side of the enclosed space 81 from the opening end 82a of the light passage opening 82 on the enclosed space 81 side, and the plasma light exit window 20B is located on the opposite side of the enclosed space 81 from the opening end 83a of the light passage opening 83 on the enclosed space 81 side, and each of the light passage openings 82 and 83 is narrowed with respect to the enclosed space 81. This makes it possible to more reliably suppress the occurrence of convection in the gas G. This improves the quality of the output light.

In the light-emitting envelope 1A, the enclosure 8 is made of an insulating material. As a result, the tip 31 of the first electrode 3 and the tip 41 of the second electrode 4 are surrounded by the insulating enclosure 8, so that even if the enclosed space 81 is narrowed, plasma can be reliably generated and the plasma can be stably maintained. This improves the quality of the output light.

In the light-emitting envelope 1A, the housing 7 has a laser light exit window 20C facing the laser light passage window 20D, and the laser light exit window 20C emits the laser light L1 that has passed through the laser light passage window 20D to the outside of the housing 7. This allows the laser light L1 that has entered the space in which the gas G exists and has passed through the plasma to be emitted to the outside of the housing 7 via the laser light passage window 20D of the enclosing part 8 and the laser light exit window 20C of the housing 7. In addition, since the housing 7 can be sealed by the laser light exit window 20C, the laser light passage window 20D can have an optimal configuration with respect to functions other than sealing.

In the light-emitting envelope 1A, the distance between the window member 27 of the laser light passing window 20D and the plasma region R is smaller than the distance between the window member 21 of the laser light entrance window 20A and the plasma region R, the distance between the window member 23 of the plasma light exit window 20B and the plasma region R, and the distance between the window member 25 of the laser light exit window 20C and the plasma region R. As a result, the space in which the gas G convects is narrower than when the enclosure 8 does not have the laser light passing window 20D, and it is possible to reliably suppress the occurrence of convection in the gas G in the space. As a result, noise components can be removed from the output light, improving the quality of the output light.

In the light-emitting envelope 1A, the thickness of the window member 27 of the laser light passing window 20D is thinner than the thickness of the window member 25 of the laser light exit window 20C. As a result, in the window member 27 of the laser light passing window 20D, which is closer to the plasma than the other window members 21, 23, and 25 and therefore is more susceptible to the thermal influence of the plasma, the influence of thermal expansion and the like can be reduced by making the thickness thinner, and damage to the window member 27 of the laser light passing window 20D and changes in the fixed state can be suppressed. Therefore, the light-emitting envelope 1A can be stably operated, and the quality of the output light can be improved.
[Second embodiment]

As shown in Figures 4, 5, and 6, the luminous envelope 1B of the second embodiment differs from the luminous envelope 1A of the first embodiment mainly in that the second electrode 4 is held by the second holding portion 6, and that the first surrounding portion 8A of the surrounding portion 8 is provided on the first holding portion 5, and the second surrounding portion 8B of the surrounding portion 8 is provided on the second holding portion 6. The luminous envelope 1B of the second embodiment will be described below, focusing on the differences from the luminous envelope 1A of the first embodiment.

As shown in Figures 4, 5, and 6, the first electrode 3 extends from outside the housing 7 through an electrode opening 75 of the housing 7 into the enclosed space 81. The second electrode 4 extends from outside the housing 7 through an electrode opening 76 of the housing 7 into the enclosed space 81. In the light-emitting envelope 1B, each of the first electrode 3 and the second electrode 4 is a rod-shaped member extending in the Y-axis direction.

The first holding portion 5 is an insulating member and holds the first electrode 3. The material of the first holding portion 5 is an insulating material having high temperature resistance, such as ceramic. In the luminous envelope 1B, the first holding portion 5 has a main body portion 51 and a cylindrical portion 52. The cylindrical portion 52 is located on the opposite side of the plasma region R with respect to the main body portion 51, and is disposed outside the electrode opening 75 of the housing 7. The main body portion 51 extends from the outside of the housing 7 into the electrode opening 75. A through hole 51a is formed in the main body portion 51. The through hole 51a extends in the Y-axis direction and opens into the enclosed space 81 and the inside of the cylindrical portion 52. The intermediate portion 32 of the first electrode 3 is disposed in the through hole 51a. The side of the intermediate portion 32 is hermetically joined to the inner surface of the through hole 51a by a joining material such as a metal brazing material. The base end 33 of the first electrode 3 is disposed inside the cylindrical portion 52.

The first holding part 5 is fixed to the housing 7. In the luminous envelope 1B, the first holding part 5 is fixed to the housing 7 via a cylindrical connecting member 9. The connecting member 9 has a cylindrical part 91 and an inward flange part 92. The inward flange part 92 is provided at the end of the cylindrical part 91 opposite the housing 7. The connecting member 9 is made of a metal material such as Kovar. The inward flange part 92 is hermetically joined to the outward flange part 54 provided on the main body part 51 of the first holding part 5 by a joining material such as a metal brazing material. The end of the cylindrical part 91 on the housing 7 side is hermetically joined to the housing 7 by, for example, laser welding.

The second holding portion 6 is an insulating member and holds the second electrode 4. The material of the second holding portion 6 is an insulating material having high temperature resistance, such as ceramic. In the luminous envelope 1B, the second holding portion 6 has a main body portion 61 and a cylindrical portion 62. The cylindrical portion 62 is located on the opposite side of the plasma region R with respect to the main body portion 61, and is disposed outside the electrode opening 76 of the housing 7. The main body portion 61 extends from the outside of the housing 7 into the electrode opening 76. A through hole 61a is formed in the main body portion 61. The through hole 61a extends in the Y-axis direction and opens into the enclosed space 81 and the inside of the cylindrical portion 62. The middle portion 42 of the second electrode 4 is disposed in the through hole 61a. The side of the middle portion 42 is hermetically joined to the inner surface of the through hole 61a by a joining material such as a metal brazing material. The base end 43 of the second electrode 4 is disposed inside the cylindrical portion 62.

The second holding part 6 is fixed to the housing 7. In the luminous envelope 1B, the second holding part 6 is fixed to the housing 7 via a cylindrical connecting member 11. The connecting member 11 has a cylindrical part 111 and an inward flange part 112. The inward flange part 112 is provided at the end of the cylindrical part 111 opposite the housing 7. The material of the connecting member 11 is a metal material such as Kovar. The inward flange part 112 is hermetically joined to the outward flange part 64 provided on the main body part 61 of the second holding part 6 by a joining material such as a metal brazing material. The end of the cylindrical part 111 on the housing 7 side is hermetically joined to the housing 7 by, for example, laser welding.

The first surrounding portion 8A of the surrounding portion 8 has the first portion 80D of the main body portion 80 and the laser light passing window portion 20D. The first portion 80D is a portion of the main body portion 80 that defines most of the surrounding space 81, the three light passing openings 82, 83, 84, and the electrode opening 85. The material of the first portion 80D is an insulating material that has high temperature resistance, such as ceramic. The first portion 80D is formed integrally with the first holding portion 5 with the electrode opening 85 communicating with the through hole 51a. In other words, the first surrounding portion 8A is provided in the first holding portion 5.

The second surrounding portion 8B of the surrounding portion 8 has the second portion 80E of the main body portion 80. The second portion 80E is a part of the main body portion 80 on the electrode opening 86 side in the surrounding space 81, and a portion that defines the electrode opening 86. The material of the second portion 80E is an insulating material that has high temperature resistance, such as ceramic. The second portion 80E is formed integrally with the second holding portion 6 with the electrode opening 86 communicating with the through hole 61a. In other words, the second surrounding portion 8B of the surrounding portion 8 is provided in the second holding portion 6.

As described above, in the light-emitting envelope 1B, the first surrounding portion 8A of the surrounding portion 8 is provided on the insulating first holding portion 5 that holds the first electrode 3, and the second surrounding portion 8B of the surrounding portion 8 is provided on the insulating second holding portion 6 that holds the second electrode 4. This allows the surrounding portion 8 to be easily configured using the first holding portion 5 that holds the first electrode 3 and the second holding portion 6 that holds the second electrode 4. In addition, since the tip portion 31 of the first electrode 3 and the tip portion 41 of the second electrode 4 are surrounded by the insulating surrounding portion 8, even if the surrounded space 81 is narrowed, plasma can be reliably generated and the plasma can be stably maintained. Therefore, the quality of the output light can be improved.
[Third embodiment]

As shown in Figures 7, 8 and 9, the luminous envelope 1C of the third embodiment is mainly different from the luminous envelope 1A of the first embodiment in that the enclosure 8 is not disposed within the storage space 71 of the housing 7. In the luminous envelope 1C, the storage structure 2 is constituted by the housing 7 having the laser light entrance window 20A, the plasma light exit window 20B and the laser light exit window (third window) 20C, and the enclosed space 81 including the plasma region R is defined by the housing 7. In the luminous envelope 1C, the light passing area of the laser light exit window 20C is defined by the wall 70a of the main body 70 having light-shielding properties.

As described above, in the light-emitting envelope 1C, the containing structure 2 has the housing 7 having the laser light entrance window 20A, the plasma light exit window 20B, the laser light exit window 20C and the wall 70a, and the housing 7 defines the enclosed space 81 including the plasma region R. This makes it possible, with a simpler configuration, to emit the laser light L1 that has entered the space in which the gas G is present and has passed through the plasma to the outside of the housing 7 via the laser light exit window 20C of the housing 7.
[Modification]

The present invention is not limited to the above-described embodiment. For example, in the luminous envelope 1A of the first embodiment and the luminous envelope 1B of the second embodiment, the window member 21 of the laser light entrance window 20A is located outside the light passing opening 82, but a part of the window member 21 may be located inside the light passing opening 82. The laser light entrance window 20A may be located on the opposite side of the enclosed space 81 with respect to the opening end 82a on the enclosed space 81 side of the light passing opening 82.

In the luminous envelope 1A of the first embodiment and the luminous envelope 1B of the second embodiment, the window member 23 of the plasma light exit window 20B is located outside the light passing opening 83, but a part of the window member 23 may be located inside the light passing opening 83. The plasma light exit window 20B may be located on the opposite side of the enclosed space 81 with respect to the opening end 83a of the light passing opening 83 on the enclosed space 81 side.

In the luminous envelope 1A of the first embodiment and the luminous envelope 1B of the second embodiment, in the enclosure 8, at least one of the light passing opening 82 and the light passing opening 83 may be narrowed relative to the enclosed space 81. Even in this case, it is possible to reliably suppress the occurrence of convection in the gas G.

In the luminous envelope 1B of the second embodiment, at least a portion of the surrounding portion 8 may be provided on the insulating first holding portion 5 that holds the first electrode 3. Even in this case, at least a portion of the surrounding portion 8 may be formed using the first holding portion 5 that holds the first electrode 3. As an example, the entire surrounding portion 8 may be provided on the insulating first holding portion 5 that holds the first electrode 3.

The luminous envelope 1A of the first embodiment, the luminous envelope 1B of the second embodiment, and the luminous envelope 1C of the third embodiment may not have the first electrode 3 and the second electrode 4. Even in this case, plasma can be generated by irradiating the gas G with the laser light L1. In the luminous envelope 1A of the first embodiment, the luminous envelope 1B of the second embodiment, and the luminous envelope 1C of the third embodiment, the housing 7 may be provided with a plurality of plasma light emission windows 20B, and the containing structure 2 may be configured so that the plasma light L2 is emitted from each plasma light emission window 20B.

1A, 1B, 1C...luminous envelope, 2...accommodating structure, 3...first electrode, 4...second electrode, 5...first holding portion, 6...second holding portion, 7...housing, 8...enclosure portion, 8A...first enclosing portion, 8B...second enclosing portion, 20A...laser light entrance window portion (first window portion), 20B...plasma light exit window portion (second window portion), 20C...laser light exit window portion (fourth window portion, third window portion), 20D...laser light passage window portion (third window portion), 21, 23, 25, 27...window member, 31...tip portion (first tip portion), 41...tip portion (second tip portion), 70a, 80a...wall portion, 81...enclosed space, 82...light passing opening (first opening), 82a...opening end, 83...light passing opening (second opening), 83a...opening end, G...gas, L1...laser light (first light), L2...plasma light (second light), R...plasma region.

Claims (10)

a containment structure containing a gas for generating a plasma;
The containment structure includes:
a first window portion that allows a first light for maintaining the plasma in a plasma region where the plasma is generated to enter the plasma region;
a second window portion that allows the second light emitted from the plasma to exit from the plasma region;
a third window portion facing the first window portion across the plasma region and allowing the first light transmitted through the plasma to exit from the plasma region;
A light-emitting envelope having a light-blocking wall portion defining at least a light passage area of the third window portion. The light-emitting envelope according to claim 1, wherein the third window also emits the second light emitted from the plasma region toward the third window. The containment structure includes:
a housing having the first window portion and the second window portion;
The luminous envelope according to claim 1 or 2, further comprising: an enclosure having the third window and the wall and defining an enclosed space including the plasma region within the housing. the enclosure portion has a first opening corresponding to the first window portion and a second opening corresponding to the second window portion,
the first window portion is located on an opposite side to the enclosed space with respect to an opening end of the first opening on the enclosed space side,
the second window portion is located on an opposite side to the enclosed space with respect to an opening end of the second opening on the enclosed space side,
4. The luminescent envelope of claim 3, wherein at least one of the first opening and the second opening is constricted relative to the enclosed space. a first electrode having a first tip portion facing the plasma region within the housing;
a second electrode having a second tip portion facing the plasma region within the housing and facing the first tip portion across the plasma region;
a first holding part having insulating properties and fixed to the housing, the first holding part holding the first electrode,
the surrounding portion is an insulating surrounding portion that surrounds the plasma region, the first tip portion, and the second tip portion within the housing, and has a first opening corresponding to the first window portion and a second opening corresponding to the second window portion;
The luminescent envelope according to claim 3 , wherein at least a portion of the surrounding portion is provided on the first holding portion. The second electrode is held by an insulating second holding part fixed to the housing.
The enclosure portion has a first enclosure portion and a second enclosure portion,
the first surrounding portion is provided on the first holding portion as the part,
The luminescent envelope according to claim 5 , wherein the second surrounding portion is provided on the second holding portion. The housing further includes a fourth window portion facing the third window portion,
The luminous envelope according to claim 3 , wherein the fourth window portion allows the first light transmitted through the third window portion to be emitted to the outside of the housing. each of the first window portion, the second window portion, the third window portion, and the fourth window portion has a window member;
The luminous envelope according to claim 7, wherein a distance between the window member and the plasma region of the third window portion is smaller than any of a distance between the window member and the plasma region of the first window portion, a distance between the window member and the plasma region of the second window portion, and a distance between the window member and the plasma region of the fourth window portion. The luminous envelope according to claim 8, wherein the thickness of the window member of the third window portion is smaller than the thickness of the window member of the fourth window portion. the housing structure includes a housing having the first window portion, the second window portion, the third window portion, and the wall portion,
The luminescent envelope of claim 1 or 2, wherein the housing defines an enclosed space that contains the plasma region.

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