Luminous envelope and light source device

Abstract

To provide a light-emitting encapsulation body and a light source device with an improved lifetime.SOLUTION: The light-emitting encapsulation body includes an enclosure, a first window portion, and a second window portion 30. The enclosure accommodates a light-emitting gas in an inner space. The first window portion is provided in the enclosure. A first light beam, which is a laser beam for maintaining a plasma generated in the light-emitting gas, enters the first window portion. The second window portion 30 is provided in the enclosure. A second light beam L2, which is light beam from the plasma, is emitted from the second window portion. The second window portion 30 has a second window member 31 made of a material containing diamond. A protective layer 80 made of an inorganic material is formed on a surface of at least an inner space S1 side in the second window member 31.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a light-emitting envelope and a light source device. [Background technology]

[0002] A related technique is, for example, a laser excitation light source described in Patent Document 1. In a laser excitation light source, plasma generated in a light emitting gas is maintained by irradiation with laser light, and light from the plasma is output as output light. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 7,435,982 Summary of the Invention [Problem to be solved by the invention]

[0004] In the laser pumped light source described above, it is conceivable to form the window member from diamond. The inventors have found that when such a laser pumped light source is continuously driven, depending on the driving conditions, a phenomenon occurs in which the window member becomes opaque. In order to improve the life of the laser pumped light source, it is necessary to suppress the occurrence of this phenomenon.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a light emitting envelope and a light source device with improved life span. [Means for solving the problem]

[0006] The luminous envelope of the present invention comprises a housing that contains a luminous gas in its internal space, a first window portion provided in the housing through which a first light, which is a laser beam for maintaining plasma generated in the luminous gas, enters, and a second window portion provided in the housing through which a second light, which is light from the plasma, exits, and at least one of the first and second windows has a window member made of a material containing diamond, and a protective layer made of an inorganic material is formed on at least the surface of the window member facing the internal space.

[0007] In this luminous envelope, at least one of the window members of the first window portion and the second window portion is made of a material containing diamond. In this case, there is a possibility that the window member may become opaque (opacification phenomenon) as described above. In this regard, in this luminous envelope, a protective layer made of an inorganic material is formed on at least the surface of the window member facing the internal space. This makes it possible to suppress the occurrence of the opacification phenomenon and improve the lifespan of the luminous envelope.

[0008] The protective layer may include a plurality of layers, in which case the occurrence of the opacification phenomenon can be more reliably suppressed.

[0009] The protective layer may contain a material that has a lower transmittance to ultraviolet light than diamond, which can prevent the window member from becoming opaque due to the influence of ultraviolet light, thereby more reliably preventing the occurrence of the opacification phenomenon.

[0010] The protective layer may contain a material that has a higher transmittance for ultraviolet light than diamond, in which case the first light or the second light containing ultraviolet light can enter or exit through the window.

[0011] The protective layer may include an ALD layer, which is a uniform and dense layer, and thus can more reliably suppress the occurrence of opacification.

[0012] The protective layer may include a first ALD layer made of a first material and a second ALD layer made of a second material different from the first material. In this case, the protective layer including multiple layers can more reliably suppress the occurrence of opacification. Furthermore, the ALD layer being a uniform and dense layer can also more reliably suppress the occurrence of opacification.

[0013] The protective layer may include a layer made of Al2O3. In this case, since Al2O3 has a higher transmittance for ultraviolet light than diamond, the first light or the second light containing ultraviolet light can be incident or emitted through the window portion.

[0014] The protective layer may include a layer made of SiO2. In this case, since SiO2 has a higher transmittance for ultraviolet light than diamond, the first light or the second light containing ultraviolet light can enter or exit through the window portion.

[0015] The protective layer may include a layer made of TiO2. In this case, TiO2 has a lower transmittance to ultraviolet light than diamond, which can prevent the window member from becoming opaque due to the influence of ultraviolet light, thereby more reliably preventing the occurrence of the opacification phenomenon.

[0016] The protective layer may be made of Al2O3. In this case, the first light or the second light containing ultraviolet light can be incident or emitted from the window portion.

[0017] The protective layer may include a first layer made of Al2O3 and a second layer made of SiO2. In this case, the protective layer including multiple layers can more reliably suppress the occurrence of the opacification phenomenon. Also, the first light or the second light including ultraviolet light can be incident or emitted through the window portion.

[0018] The protective layer may include a first layer made of Al2O3 and a second layer made of TiO2. In this case, the protective layer including multiple layers can more reliably suppress the occurrence of opacification. Furthermore, the window member can be prevented from becoming opaque due to the influence of ultraviolet light, and the occurrence of opacification can be more reliably suppressed.

[0019] The protective layer may be made of one or more ALD layers, which are uniform and dense layers, and thus can more reliably suppress the occurrence of opacification.

[0020] The housing may be made of a metal material, in which case the pressure of the luminous gas sealed therein can be increased, and the intensity of the second light emitted from the second window can be increased.

[0021] The window member may be fixed to a frame member made of a metal material and fixed to the housing via the frame member, and the protective layer may be formed so as to extend from the window member to the frame member. In this case, it is possible to suppress the release of impurity gases from the frame member, and it is possible to more reliably suppress the occurrence of the opacity phenomenon.

[0022] The window member may be fixed to the frame member by a bonding material, and the protective layer may cover the bonding material, in which case foreign matter can be prevented from being released from the bonding material.

[0023] The pressure of the luminous gas enclosed in the housing may be 3 MPa or more. In this case, the intensity of the second light emitted from the second window can be increased, but the opacity phenomenon is more likely to occur. However, with this luminous envelope, the opacity phenomenon can be suppressed even in such cases.

[0024] The light source device of the present invention includes the light-emitting envelope and a light introducing portion that allows the first light to enter the first window portion. For the reasons described above, this light source device can have an improved lifespan. [Effects of the Invention]

[0025] According to the present invention, it is possible to provide a light emitting envelope and a light source device with an improved lifespan. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a perspective view of the luminous envelope according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is an enlarged view of a second window member and a second frame member. [Figure 5] FIG. 2 is a cross-sectional view showing the configuration of a protective layer. [Figure 6] (a) is a photograph showing the first sample immediately after the start of operation, and (b) is a photograph showing the first sample after 327 hours have passed. [Figure 7] (a) and (b) are photographs showing the second sample immediately after the start of operation. [Figure 8] (a) and (b) are photographs showing the second sample after 168 hours. [Figure 9] (a) and (b) are photographs showing the second sample after 500 hours. [Figure 10] (a) and (b) are photographs showing the second sample after 1051 hours. [Figure 11] (a) is a photograph showing the second sample immediately after the start of operation, and (b) is a photograph showing the second sample after 670 hours have passed. [Figure 12] FIG. 1(a) is a cross-sectional view showing an example of a protective layer made of one ALD layer, and FIG. 1(b) is a cross-sectional view showing an example of a protective layer made of a first ALD layer and a second ALD layer. [Figure 13] (a) and (b) are photographs showing the third sample immediately after the start of operation. [Figure 14] (a) and (b) are photographs showing the third sample after 168 hours. [Figure 15](a) and (b) are photographs showing the third sample after 500 hours. [Figure 16] (a) and (b) are photographs showing the third sample after 1000 hours. [Figure 17] FIG. 4 is an enlarged view of the vicinity of the first window member. [Figure 18] Photographs (a) and (b) show examples of foreign matter occurring on a window member. [Figure 19] (a) and (b) are photographs showing another example of foreign matter occurring on a window member, where (a) shows the state immediately after operation began, and (b) shows the state after 46 hours. [Figure 20] (a) is a photograph showing the fourth sample immediately after operation began, (b) is a photograph showing the fourth sample after 147 hours, and (c) is a photograph showing the fourth sample after 712 hours. [Figure 21] (a) is a photograph showing the fifth sample immediately after the start of operation, (b) is a photograph showing the fifth sample after 147 hours, and (c) is a photograph showing the fifth sample after 712 hours. [Figure 22] (a) is a photograph showing the sixth sample immediately after the start of operation, and (b) is a photograph showing the sixth sample after 168 hours have passed. [Figure 23] (a) is a photograph showing the sixth sample after 504 hours have passed, and (b) is a photograph showing the sixth sample after 1051 hours have passed. [Figure 24] (a) is a photograph showing the seventh sample immediately after the start of operation, and (b) is a photograph showing the seventh sample after 168 hours have passed. [Figure 25] (a) is a photograph showing the seventh sample after 504 hours, and (b) is a photograph showing the seventh sample after 1051 hours. [Figure 26] (a) is a photograph showing the eighth sample immediately after the start of operation, and (b) is a photograph showing the eighth sample after 168 hours have passed. [Figure 27](a) is a photograph showing the eighth sample after 504 hours, and (b) is a photograph showing the eighth sample after 1051 hours. [Figure 28] FIG. 4 is a cross-sectional view of the vicinity of the second end of the sealing tube. [Figure 29] FIG. 10 is a cross-sectional view of a light-emitting envelope according to a second embodiment. [Figure 30] FIG. 2 is a plan view of a getter section. [Figure 31] 1(a) is a front view of the getter section, and FIG. 1(b) is a side view of the getter section. [Figure 32] FIG. 10 is another cross-sectional view of the luminous envelope according to the second embodiment. [Figure 33] Photographs (a) and (b) show examples of foreign matter occurring on electrodes. [Figure 34] (a) is a photograph showing the 9th sample immediately after the start of operation, (b) is a photograph showing the 9th sample after 260 hours have passed, and (c) is a photograph showing the 9th sample after 670 hours have passed. [Figure 35] (a), (b), and (c) are photographs showing the 10th sample just before the start of operation. [Figure 36] (a), (b), and (c) are photographs showing the 10th sample immediately after the start of operation. [Figure 37] (a), (b), and (c) are photographs showing the 10th sample after 165 hours. [Figure 38] (a) and (b) are photographs showing the 11th sample immediately before the start of operation. [Figure 39] (a) and (b) are photographs showing the 11th sample immediately after the start of operation. [Figure 40] (a) and (b) are photographs showing Sample 11 after 165 hours. [Figure 41] (a) and (b) are photographs showing the 12th sample immediately before the start of operation. [Figure 42] (a) and (b) are photographs showing the 12th sample immediately after the start of operation. [Figure 43](a) and (b) are photographs showing Sample 12 after 165 hours. [Figure 44] (a) is a photograph showing the 13th sample immediately after the start of operation, and (b) is a photograph showing the 13th sample after 262 hours have passed. [Figure 45] FIG. 10 is a cross-sectional view of a luminous envelope according to a fifth modified example. [Figure 46] FIG. 10 is a cross-sectional view of a luminous envelope according to a sixth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0027] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted. [First embodiment] [Laser excitation light source]

[0028] As shown in FIGS. 1 to 3, the luminous envelope 1 includes a housing 10. The housing 10 is filled with a luminous gas GS. The luminous gas GS is, for example, xenon, which is a discharge gas in this example. The luminous envelope 1 constitutes a laser excitation light source (light source device) together with a laser light source that outputs a first light L1 that is, for example, a laser beam. In the laser excitation light source, plasma is generated in the luminous gas GS. The first light L1, which is a laser beam for maintaining the plasma, is incident on the luminous envelope 1, and second light L2, which is light from the plasma, is emitted from the luminous envelope 1 as output light. The first light is, for example, light in the near-infrared region, and has a wavelength of, for example, about 800 nm to 1100 nm. The second light L2 is, for example, light in the ultraviolet to mid-infrared region, and has a wavelength of, for example, about 220 nm to 20 μm.

[0029] The laser excitation light source includes, for example, a light-emitting envelope 1 and the above-described laser light source, as well as a mirror and an optical system, and these elements are housed in a case. The laser light source is, for example, a laser diode. The mirror reflects the first light L1 from the laser light source toward the optical system. The optical system includes one or more lenses. The optical system focuses the first light L1 from the mirror and guides it to the light-emitting envelope 1. The laser light source, mirror, and optical system constitute a light introduction section that introduces the first light L1 into the housing 10 through a first window 20 described below. Alternatively, the laser excitation light source itself may not include a laser light source. For example, the laser excitation light source may include, instead of its own laser light source, an optical fiber that guides light from an externally located laser light source to the mirror. In this case, the optical fiber, mirror, and optical system constitute a light introduction section that introduces the first light L1 into the housing 10 through the first window 20. [Luminous envelope]

[0030] In addition to the housing 10, the luminous envelope 1 further includes a first window 20, two second windows 30, a first electrode 40, and a second electrode 50.

[0031] The housing 10 has a housing main body 11. The housing main body 11 is made of a metal material and is formed in a generally box-like shape, and contains a light-emitting gas GS. More specifically, a sealed internal space S1 is formed within the housing main body 11, and the internal space S1 is filled with the light-emitting gas GS. An example of a metal material constituting the housing main body 11 is stainless steel. In this case, the housing main body 11 has a light-blocking property against the first light L1 and the second light L2. In other words, the housing main body 11 is made of a light-blocking material that does not transmit the first light L1 and the second light L2.

[0032] The housing main body 11 is formed with a first opening 12 and two second openings 13. A first light L1 enters the first opening 12 along a first optical axis A1. The first opening 12 is formed, for example, in a circular shape when viewed from a direction parallel to the first optical axis A1 (hereinafter also referred to as the Z direction). In this example, the first optical axis A1 passes through the center of the first opening 12 when viewed from the Z direction. The first opening 12 includes an inner portion 12a, a middle portion 12b, and an outer portion 12c. The inner portion 12a opens to the internal space S1. The outer portion 12c opens to the outside of the housing main body 11. The middle portion 12b is connected to the inner portion 12a and the outer portion 12c. Each of the inner portion 12a, the middle portion 12b, and the outer portion 12c has, for example, a cylindrical shape. When viewed in the axial direction, the outer diameter of intermediate portion 12b is larger than the outer diameter of inner portion 12a, and the outer diameter of outer portion 12c is larger than the outer diameter of intermediate portion 12b. The "outer diameter" of an element when viewed in the axial direction refers to the diameter if the element is circular, or the maximum length if the element is non-circular.

[0033] The second light L2 is emitted from each second opening 13 along the second optical axis A2. When viewed from a direction parallel to the second optical axis A2 (hereinafter also referred to as the Y direction), each second opening 13 is formed in a circular shape. In this example, the second optical axis A2 passes through the center of the second opening 13 when viewed from the Y direction. Each second opening 13 includes an inner portion 13a, a middle portion 13b, and an outer portion 13c. The inner portion 13a opens to the internal space S1. The outer portion 13c opens to the outside of the housing main body 11. The middle portion 13b is connected to the inner portion 13a and the outer portion 13c. Each of the inner portion 13a, the middle portion 13b, and the outer portion 13c has, for example, a cylindrical shape. When viewed from the axial direction, the outer shape of the middle portion 13b is larger than that of the inner portion 13a, and the outer shape of the outer portion 13c is larger than that of the middle portion 13b.

[0034] The first optical axis A1 intersects with the second optical axis A2 within the internal space S1. That is, the first opening 12 and the second opening 13 are arranged so that the first optical axis A1 and the second optical axis A2 intersect with each other. An intersection C of the first optical axis A1 and the second optical axis A2 is located within the internal space S1. In this example, the first optical axis A1 intersects with the second optical axis A2 perpendicularly, but the first optical axis A1 may intersect with the second optical axis A2 at an angle other than a right angle. The first optical axis A1 is not parallel to the second optical axis A2. The first optical axis A1 does not pass through the second opening 13, and the second optical axis A2 does not pass through the first opening 12.

[0035] The first window portion 20 hermetically seals the first opening 12. The first window portion 20 has a first window member 21. The first window member 21 is formed, for example, in the shape of a circular flat plate from a light-transmitting material that transmits the first light L1. In this example, the first window member 21 is made of sapphire and transmits light with a wavelength of 5 μm or less. The first window member 21 transmits the first light L1 at the first opening 12.

[0036] The first window member 21 is fixed to the first frame member 61, and is fixed to the housing main body 11 via the first frame member 61. In the following description, the first frame member 61 will be considered to be part of the housing 10. In this case, the housing 10 has the first frame member 61 in addition to the housing main body 11 described above. However, the first frame member 61 can also be considered to be part of the first window portion 20. In this case, the housing 10 consists of only the housing main body 11.

[0037] The first frame member 61 is formed in a frame shape from a metal material such as Kovar metal. The first frame member 61 is formed in a substantially cylindrical shape overall. The first frame member 61 has a cylindrical first portion 62 and a cylindrical second portion 63 formed integrally with the first portion 62. The outer shape of the second portion 63 is larger than the outer shape of the first portion 62. The first window member 21 is disposed within the first portion 62 and fixed to the first frame member 61. Details of how the first window member 21 is fixed to the first frame member 61 will be described later.

[0038] A circular ring-shaped flange portion 63a that protrudes radially outward is formed on the outer surface of the second portion 63. The first frame member 61 is fixed to the housing main body 11 with the flange portion 63a disposed within the intermediate portion 12b of the first opening 12. In this state, a part of the first portion 62 of the first frame member 61 protrudes from the first opening 12. The first window member 21 is disposed to face the intersection C of the first optical axis A1 and the second optical axis A2. The first frame member 61 is airtightly fixed to the housing main body 11 at the flange portion 63a by, for example, laser welding.

[0039] Each second window portion 30 hermetically seals the second opening 13. Each second window portion 30 has a second window member 31. The second window member 31 is formed, for example, in the shape of a circular flat plate from a translucent material that transmits the second light L2. In this example, the second window member 31 is formed from diamond and transmits light with a wavelength of 20 μm or less. The second window member 31 transmits the second light L2 at the second opening 13.

[0040] The second window member 31 is fixed to the second frame member 71, and is fixed to the housing body 11 via the second frame member 71. In the following description, the second frame member 71 will be considered to be part of the housing 10. In this case, the housing 10 has the second frame member 71 in addition to the housing body 11 and first frame member 61 described above. However, the second frame member 71 can also be considered to be part of the second window portion 30. In this case, the housing 10 consists of only the housing body 11.

[0041] The second frame member 71 is formed in a frame shape from a metal material such as Kovar metal. The second frame member 71 is formed in a generally cylindrical shape overall. The second frame member 71 has a cylindrical first portion 72 and a cylindrical second portion 73 formed integrally with the first portion 72. The outer shape of the second portion 73 is larger than the outer shape of the first portion 72. The second window member 31 is disposed within the first portion 72 and fixed to the second frame member 71. Details of how the second window member 31 is fixed to the second frame member 71 will be described later.

[0042] A circular ring-shaped flange portion 73a that protrudes radially outward is formed on the outer surface of the second portion 73. The second frame member 71 is fixed to the housing 10 with the flange portion 73a disposed within the intermediate portion 13b of the second opening 13. In this state, a part of the first portion 72 of the second frame member 71 protrudes from the second opening 13. The second window member 31 is disposed to face the intersection C of the first optical axis A1 and the second optical axis A2. The second frame member 71 is airtightly fixed to the housing main body 11 at the flange portion 73a by, for example, laser welding.

[0043] The first electrode 40 extends along the X direction, which is perpendicular to both the Y direction and the Z direction. The first electrode 40 faces the second electrode 50 across an intersection C between the first optical axis A1 and the second optical axis A2. In the X direction, the distance between the intersection C and the tip of the first electrode 40 is equal to the distance between the intersection C and the tip of the second electrode 50. The first electrode 40 is formed of a metal material, such as tungsten. The first electrode 40 is generally rod-shaped. The first electrode 40 has a first support portion 41 on the base end side and a first discharge portion 42 located on the tip side closer to the second electrode 50 than the first support portion 41. The first electrode 40 is fixed to the housing main body 11 at the first support portion 41 via an insulating member 3 and is electrically isolated from the housing 10. The first discharge portion 42 has a smaller diameter than the first support portion 41 and has a pointed shape. The first discharge unit 42 is disposed inside the housing 10 (inside the internal space S1).

[0044] The insulating member 3 has a main body 3a and a cylindrical portion 3b. The insulating member 3 is made of an insulating material such as alumina (aluminum oxide) or ceramic. The main body 3a is formed, for example, in a cylindrical shape and holds a first support portion 41 of the first electrode 40. The cylindrical portion 3b is formed in a cylindrical shape so as to extend from the main body 3a along the X direction and surrounds a part of the first support portion 41 side (base end side) of the first discharge portion 42. A third opening 14 is formed in the housing main body 11, and the cylindrical portion 3b is disposed within the third opening 14. The insulating member 3 is hermetically fixed to the housing main body 11 via a metal connecting member 4.

[0045] The second electrode 50 extends along the X direction. The second electrode 50 faces the first electrode 40 across an intersection C between the first optical axis A1 and the second optical axis A2. The second electrode 50 is formed of a metal material such as tungsten. The second electrode 50 is generally formed in a rod shape with a larger diameter than the first electrode 40. The second electrode 50 has a second support portion 51 on the base end side and a second discharge portion 52 located on the tip side closer to the first electrode 40 than the second support portion 51. The second electrode 50 is fixed to the housing main body 11 at the second support portion 51 and is electrically connected to the housing 10. More specifically, a fourth opening 15 is formed in the housing main body 11, and the second support portion 51 is disposed within the fourth opening 15. The second discharge portion 52 has a smaller diameter than the second support portion 51 and has a pointed shape. The second discharge portion 52 is disposed within the housing 10 (within the internal space S1).

[0046] An encapsulation hole 16 is formed in the housing body 11. The encapsulation hole 16 is used to encapsulate a luminous gas GS in the internal space S1 during the manufacture of the luminous envelope 1. The encapsulation hole 16 also functions as an exhaust hole for discharging gas (remaining air and impurity gases such as gases released from the constituent materials) from the internal space S1 to the outside during the manufacture of the luminous envelope 1. A encapsulation tube 17 is connected to the encapsulation hole 16. The encapsulation tube 17 is formed in a cylindrical shape from a metal material such as copper, and has a first end 17a and a second end 17b. The first end 17a is disposed within the encapsulation hole 16, and the encapsulation tube 17 is connected to the internal space S1 at the first end 17a. The second end 17b is sealed by being crushed. Details of the sealed portion will be described later.

[0047] In the luminous envelope 1, an internal space S1 is defined by the housing 10, the first window 20, and the second window 30. In the luminous envelope 1, the internal space S1 is also defined by the first electrode 40, the second electrode 50, the insulating member 3, the connecting member 4, and the sealing tube 17. The entire internal space S1 is filled with the luminous gas GS. That is, the internal space S1 is filled with the luminous gas GS. The sealing pressure (maximum sealing pressure) of the luminous gas GS is, for example, 3 MPa (30 atmospheres) or more, but may be 5 MPa (50 atmospheres) or more. The luminous envelope 1 can withstand an internal pressure of 16 MPa or more. [Example of operation]

[0048] In the laser excitation light source, a voltage application circuit disposed inside the case applies a negative voltage pulse to the first electrode 40, with the second electrode 50 at ground potential. This causes electrons to be emitted from the first electrode 40 toward the second electrode 50. As a result, an arc discharge occurs, and plasma is generated between the first electrode 40 and the second electrode 50 (at the intersection C). This plasma is irradiated with a first light L1 from the laser light source (light introducing portion) through the first window member 21. This maintains the generated plasma. A second light L2, which is light from the plasma, is emitted to the outside through the second window member 31 as output light. In the laser excitation light source, the second light L2 is emitted from the two second window members 31 toward both sides in the Y direction. A positive voltage pulse may be applied to the first electrode 40 as a trigger voltage for generating plasma. In this case, electrons are emitted from the second electrode 50 toward the first electrode 40. [Second window member fixing method]

[0049] 4, the second window member 31 of the second window portion 30 is formed in the shape of a circular flat plate and has a first main surface 31a, a second main surface 31b, and a side surface 31c. The first main surface 31a is a light incident surface onto which the second light L2 is incident and is the surface on the internal space S1 side (the upper side in FIG. 4). The second main surface 31b is the surface opposite the first main surface 31a and is a light exit surface from which the second light L2 exits. In this example, the first main surface 31a and the second main surface 31b are flat surfaces perpendicular to the Y direction, and the side surface 31c is a cylindrical surface connected to the first main surface 31a and the second main surface 31b.

[0050] The second window member 31 is disposed within the first portion 72 of the second frame member 71. Specifically, the space within the second frame member 71 has an arrangement portion 74 formed within the first portion 72, an intermediate portion 75 formed from within the first portion 72 to within the second portion 73, and an outer portion 76 formed within the second portion 73. The intermediate portion 75 has a truncated conical shape whose outer diameter increases toward the outside in the Y direction (the side opposite to the internal space S1) (the lower side in FIG. 4). The outer portion 76 is formed in a cylindrical shape with an outer diameter larger than that of the intermediate portion 75.

[0051] The arrangement portion 74 has a cylindrical large diameter portion 74a and a cylindrical small diameter portion 74b arranged between the large diameter portion 74a and the intermediate portion 75. The outer shape of the large diameter portion 74a is larger than the outer shape of the small diameter portion 74b. The second window member 31 is arranged across the large diameter portion 74a and the small diameter portion 74b. A portion of the second main surface 31b of the second window member 31 contacts a bottom surface 74b1 of the small diameter portion 74b, and a portion of the side surface 31c of the second window member 31 contacts an inner surface 74b2 of the small diameter portion 74b.

[0052] The second window member 31 is fixed to the second frame member 71 by a bonding material 35. Specifically, the bonding material 35 bonds the side surface 31c of the second window member 31 and the first portion 72 of the second frame member 71 to each other around the entire periphery. In this example, the bonding material 35 is disposed on the large diameter portion 74a and contacts the side surface 31c as well as the bottom surface 74a1 and inner surface 74a2 of the large diameter portion 74a. The bonding material 35 is, for example, a metal brazing material, more specifically, a titanium-doped silver brazing material. The titanium-doped silver brazing material is, for example, a brazing material composed of 70% silver, 28% copper, and 2% Ti, such as TB-608T from Tokyo Blaze Co., Ltd.

[0053] A protective layer 80 is formed on the first main surface 31a of the second window member 31. In this example, the protective layer 80 is integrally formed so as to cover the entire surfaces of the second window member 31, the second frame member 71, and the bonding material 35 that are exposed to the outside. In FIG. 4, the area where the protective layer 80 is formed is indicated by a two-dot chain line. That is, the protective layer 80 is formed so as to extend from above the second window member 31 to above the second frame member 71, and covers the bonding material 35. The protective layer 80 is formed so as to cover the entire surface of the second frame member 71 except for the portions that come into contact with the second window member 31 and the bonding material 35.

[0054] 5, the protective layer 80 includes a plurality of (two in this example) first layers 81 and a plurality of (two in this example) second layers 82. The plurality of first layers 81 and the plurality of second layers 82 are alternately stacked on the first main surface 31a of the second window member 31. In this example, the first layers 81 are in contact with the first main surface 31a, and the second layers 82 are exposed to the outside.

[0055] The protective layer 80 is made of an inorganic material and transmits at least a portion of the second light L2. As an example, the first layer 81 is an ALD layer (first ALD layer) made of Al2O3 (first material), and the second layer 82 is an ALD layer (second ALD layer) made of TiO2 (second material). The ALD layer is a layer formed by atomic layer deposition (ALD). The transmittance of Al2O3 to ultraviolet light is higher than that of diamond. The transmittance of TiO2 to ultraviolet light is lower than that of diamond. Therefore, in this example, most of the ultraviolet light contained in the second light L2 is absorbed by the second layer 82. The protective layer 80 has a thickness of, for example, about 0.1 μm.

[0056] 6 to 10, the suppression of the opacification phenomenon by the protective layer 80 will be described. In the case where the window member is made of diamond, if the laser excitation light source is continuously driven, the window member may become opaque (opacification phenomenon) depending on the driving conditions.

[0057] FIG. 6(a) is a photograph showing the first sample immediately after the start of operation, and FIG. 6(b) is a photograph showing the first sample after 327 hours. The first sample corresponds to a configuration in which the protective layer 80 is not formed on the luminous envelope 1. The photographs on the left side of FIGS. 6(a) and 6(b) are focused on the second window member 31, while the photographs on the right side of FIGS. 6(a) and 6(b) are focused on the first electrode 40 and the second electrode 50. In FIGS. 6(a) and 6(b), the first electrode 40 and the second electrode 50 are photographed through the second window member 31. This also applies to the photographs on the right side of FIGS. 7(b), 8(b), 9(b), 10(b), 11(a) and 11(b), 13(b), 14(b), 15(b), and 16(b), which will be described later.

[0058] 6(a) and 6(b), immediately after the start of operation, the first electrode 40 and the second electrode 50 were visible through the second window member 31. However, after 327 hours had passed, the visible light transmittance of the second window member 31 decreased, and the first electrode 40 and the second electrode 50 could no longer be seen through the second window member 31. After 327 hours had passed, the color of the second window member 31 had changed to white, and the second window member 31 had become opaque.

[0059] It is believed that this opacity phenomenon can occur due to at least one of the following factors. First, it is believed that the second window member 31 is worn down into a crater shape by impurity gas (gas other than the luminous gas GS, such as oxygen) present in the internal space S1 of the housing 10. Another possible factor is the influence of ultraviolet light contained in the second light L2, which is light from the plasma. Yet another possible factor is the rise in temperature of the luminous envelope 1 during operation. During operation, the temperature of the luminous envelope 1 rises due to irradiation with laser light and radiant heat from the plasma.

[0060] 7 to 10 are photographs showing the second sample immediately after the start of operation, after 168 hours, after 500 hours, and after 1051 hours, respectively. The second sample corresponds to the luminous envelope 1. In FIG. 7(a), the focus is on the second window member 31, and in FIG. 7(b), the focus is on the first electrode 40 and the second electrode 50. This is also true for FIGS. 8 to 10. FIG. 11(a) is a photograph showing the second sample immediately after the start of operation, and FIG. 11(b) is a photograph showing the second sample after 670 hours. In the photographs on the left of FIGS. 11(a) and 11(b), the focus is on the second window member 31, and in the photographs on the right of FIGS. 11(a) and 11(b), the focus is on the first electrode 40 and the second electrode 50.

[0061] 7 to 11, in the second sample, the opacification phenomenon did not occur even after 1051 hours had passed since the start of operation. These results show that the formation of the protective layer 80 can suppress the occurrence of the opacification phenomenon.

[0062] As described above, in the luminous envelope 1, the second window member 31 of the second window portion 30 through which the second light L2 exits is made of a material containing diamond. In this case, there is a possibility that the above-mentioned phenomenon of the second window member 31 becoming opaque (opacification phenomenon) may occur. In this regard, in the luminous envelope 1, a protective layer 80 made of an inorganic material and allowing at least a portion of the second light L2 to transmit is formed on the first main surface 31a (surface on the internal space S1 side) of the second window member 31. This makes it possible to prevent, for example, impure gases present in the internal space S1 inside the housing 10 from coming into contact with the second window member 31. As a result, the occurrence of the opacification phenomenon can be prevented, and the life of the luminous envelope 1 can be improved.

[0063] The protective layer 80 includes a plurality of layers, which makes it possible to more reliably prevent the occurrence of the opacity phenomenon.

[0064] Protective layer 80 contains a material (TiO2) whose transmittance to ultraviolet light is lower than that of diamond, which makes it possible to prevent second window member 31 from becoming opaque due to the influence of ultraviolet light, thereby more reliably preventing the occurrence of the opacity phenomenon.

[0065] The protective layer 80 includes an ALD layer. This makes it possible to more reliably suppress the occurrence of the opacification phenomenon because the ALD layer is a uniform and dense layer.

[0066] The protective layer 80 includes a first ALD layer (first layer 81) made of a first material and a second ALD layer (second layer 82) made of a second material different from the first material. Since the protective layer 80 includes multiple layers, the occurrence of opacification can be more reliably suppressed. Furthermore, since the ALD layer is a uniform and dense layer, the occurrence of opacification can be more reliably suppressed. Furthermore, although holes may be formed in the ALD layer with a certain probability during layer formation, the presence of the first ALD layer and the second ALD layer made of different materials makes it possible to differentiate the positions of the holes between the first ALD layer and the second ALD layer. As a result, it is possible to suppress the occurrence of a situation in which impurity gases present in the internal space S1 within the housing 10 come into contact with the second window member 31 through the holes.

[0067] This point will be further explained with reference to FIG. 12. FIG. 12(a) is a cross-sectional view showing an example (first modified example) of a protective layer 80 consisting of only one ALD layer 83. The ALD layer 83 is made of, for example, Al2O3. As with the first embodiment, the first modified example can also suppress the occurrence of the opacification phenomenon and improve the life of the light-emitting envelope 1. Furthermore, since Al2O3 has a higher transmittance for ultraviolet light than diamond, the second light L2 containing ultraviolet light can be emitted from the second window portion 30. Furthermore, a layer made of Al2O3 can be stably formed on the second window member 31 made of diamond.

[0068] 12(a), holes (pinholes) HL ​​may be formed in the ALD layer 83 with a certain probability during layer formation. In this case, there is a risk that impurity gas GR present in the internal space S1 of the housing 10 may come into contact with the second window member 31 through the holes HL. In contrast, in the light-emitting envelope 1 of the first embodiment, the protective layer 80 includes two ALD layers (a first layer 81 and a second layer 82) made of different materials. This allows the position of the hole HL1 formed in the first layer 81 to be different from the position of the hole HL2 formed in the second layer 82, as shown in FIG. 12(b). As a result, the impurity gas GR is less likely to reach the second window member 31 through the holes HL1 and HL2, and the impurity gas GR can be prevented from coming into contact with the second window member 31.

[0069] The protective layer 80 includes a layer (second layer 82) made of, for example, TiO2. This prevents the second window member 31 from becoming opaque due to the influence of ultraviolet light, as TiO2 has a lower transmittance to ultraviolet light than diamond, making it possible to more reliably prevent the occurrence of the opacity phenomenon.

[0070] The protective layer 80 includes a first layer 81 made of Al2O3 and a second layer 82 made of TiO2. As a result, the protective layer 80 includes multiple layers, which more reliably suppresses the occurrence of opacification. Furthermore, the second window member 31 can be prevented from becoming opaque due to the effects of ultraviolet light, which more reliably suppresses the occurrence of opacification.

[0071] The housing 10 is formed of a metal material. In this case, the pressure of the luminous gas GS can be increased, thereby increasing the intensity of the second light L2 emitted from the second window portion 30. Furthermore, in this case, impurity gases are more likely to be present in the internal space S1, making the opacity phenomenon more likely to occur. The luminous gas GS is sealed in the housing 10 under high vacuum conditions by vacuum baking. However, if the temperature rises or light is irradiated during operation, impurity gases may be released from the housing 10. For example, impurity gases adsorbed to irregularities on the surface of the housing 10 may be released during operation. If the housing 10 is formed by cutting, large irregularities are likely to be formed. Furthermore, impurity gases occluded in the housing 10 may also be released. In this regard, the luminous envelope 1 can suppress the opacity phenomenon even when impurity gases are more likely to be present in the internal space S1.

[0072] The protective layer 80 is formed so as to extend from above the second window member 31 to above the second frame member 71. This makes it possible to prevent impurity gases from being released from the second frame member 71, and more reliably prevents the occurrence of the opacity phenomenon.

[0073] The protective layer 80 covers the bonding material 35 that bonds the second window member 31 and the second frame member 71. This makes it possible to prevent foreign matter from being released from the bonding material 35.

[0074] The pressure of the luminous gas GS enclosed in the housing 10 is 3 MPa or more. In this case, the brightness of the plasma generated in the luminous gas GS can be increased, thereby increasing the intensity of the second light L2 emitted from the second window portion 30. For example, when the enclosed pressure is 3 MPa, the intensity of the second light L2 increases by about five times or more compared to when the enclosed pressure is 1 MPa. When the enclosed pressure is 5 MPa, the intensity of the second light L2 increases by about eight times compared to when the enclosed pressure is 1 MPa. On the other hand, the increase in the intensity of the second light L2 makes the opacification phenomenon more likely to occur. Furthermore, the increase in light output increases the temperature of the luminous envelope 1 during operation, making the opacification phenomenon more likely to occur. Furthermore, when the enclosed pressure increases, the presence of impurity gas in the internal space S1 also makes the opacification phenomenon more likely to occur. In this regard, the luminous envelope 1 can suppress the occurrence of the opacification phenomenon even in such cases.

[0075] As a second modification, in the first embodiment, the second layer 82 may be an ALD layer (second ALD layer) made of SiO2 (second material). The transmittance of SiO2 to ultraviolet light is higher than that of diamond, but lower than that of Al2O3. As with the first embodiment, the second modification can also suppress the occurrence of the opacification phenomenon, thereby improving the life of the luminous envelope 1.

[0076] This point will be explained with reference to FIGS. 13 to 16. FIGS. 13 to 16 are photographs showing the third sample immediately after the start of operation, after 168 hours, after 500 hours, and after 1000 hours, respectively. The third sample corresponds to the second modified example. In FIG. 13(a), the focus is on the second window member 31, and in FIG. 13(b), the focus is on the first electrode 40 and the second electrode 50. This also applies to FIGS. 14 to 16. As shown in FIGS. 13 to 16, the opacification phenomenon did not occur in the third sample even after 1000 hours had passed since the start of operation.

[0077] In the second modification, the protective layer 80 is made of only a material that has a higher transmittance to ultraviolet light than diamond. This allows the second light L2 containing ultraviolet light to be emitted from the second window 30.

[0078] In the first embodiment, the protective layer 80 only needs to cover at least a portion of the first main surface 31a of the second window member 31. For example, the protective layer 80 may be formed only on the first main surface 31a. Alternatively, the protective layer 80 may be formed so as to cover only the surfaces of the second window member 31, the second frame member 71, and the bonding material 35 that are exposed to the internal space S1. The protective layer 80 only needs to be able to transmit at least a portion of the second light L2. As in the first embodiment, the protective layer 80 may transmit a portion of the second light L2, or the protective layer 80 may transmit all of the second light L2. In the first embodiment, the protective layer 80 is an ALD layer. However, the protective layer 80 may also be a layer formed by vapor deposition. For example, the protective layer 80 may be a layer formed by sputtering, chemical vapor deposition (CVD), ion plating, vacuum deposition, resistance heating deposition, or the like. When the protective layer 80 is formed by vapor deposition, the protective layer 80 can be formed in any position (region). In the first embodiment, the second window member 31 of the second window portion 30 is made of a material containing diamond, and the protective layer 80 made of an inorganic material is formed on the first main surface 31a (surface on the internal space S1 side) of the second window member 31, but instead of or in addition to this, the first window member 21 of the first window portion 20 may be made of a material containing diamond, and the protective layer 80 made of an inorganic material may be formed on at least the surface of the first window member 21 on the internal space S1 side (second main surface 21b described below). In this case, the occurrence of opacification in the first window member 21 can be suppressed, and the life of the luminous envelope 1 can be further improved. [Fixing mode of first window member]

[0079] 17, the first window member 21 of the first window portion 20 is formed in the shape of a circular flat plate and has a first main surface 21a, a second main surface 21b, and a side surface 21c. The first main surface 21a is a light incident surface onto which the first light L1 is incident, and is the surface opposite to the internal space S1 (the lower side in FIG. 17). The second main surface 21b is the surface opposite to the first main surface 21a, and is a light exit surface from which the first light L1 exits. In this example, the first main surface 21a and the second main surface 21b are flat surfaces perpendicular to the Z direction, and the side surface 21c is a cylindrical surface connected to the first main surface 21a and the second main surface 21b.

[0080] The first window member 21 is disposed within a first portion 62 of the first frame member 61. The first portion 62 has a cylindrical wall portion 65 that faces the side surface 21c of the first window member 21. A circular ring-shaped flange portion 66 that protrudes radially inward is formed on an inner surface 65a of the wall portion 65. The first window member 21 is disposed within the first portion 62 of the first frame member 61 so that the first main surface 21a faces the first surface 66a of the flange portion 66 and the side surface 21c faces the inner surface 65a of the wall portion 65. An end surface 65b of the wall portion 65 in the Z direction (a direction perpendicular to the first main surface 21a) is located closer to the internal space S1 (upper side in FIG. 17 ) than the first window member 21 (second main surface 21b).

[0081] A metallized layer 26 is formed over the entire surface of the side surface 21c of the first window member 21. The metallized layer 26 is made of, for example, molybdenum manganese (Mo-Mn) and has a thickness of about several hundred μm. A plated layer 27 is formed on the metallized layer 26. The plated layer 27 is made of, for example, nickel and has a thickness of about several μm. The plated layer 27 covers the entire surface of the metallized layer 26 except for the portion in contact with the first window member 21 so that the metallized layer 26 is not exposed. The plated layer 27 functions as an oxidation prevention layer that prevents oxidation of the metallized layer 26.

[0082] The first window member 21 is joined to the first frame member 61 by the bonding material 25. Specifically, the bonding material 25 is joined to the plating layer 27, thereby bonding the first window member 21 to the first frame member 61. The bonding material 25 bonds the side surface 21c of the first window member 21 and the wall portion 65 of the first frame member 61 to each other over the entire periphery.

[0083] The bonding material 25 penetrates between the first main surface 21a of the first window member 21 and the first surface 66a of the flange portion 66 of the first frame member 61. The bonding material 25 does not conform to the first main surface 21a, and although it is in local contact with the first main surface 21a, it is not bonded to it. In other words, the bonding material 25 penetrates between the first main surface 21a and the flange portion 66 without being bonded to the first main surface 21a. In this example, the bonding material 25 is formed so as to wrap around the flange portion 66 and cover a portion of the second surface 66b of the flange portion 66. The second surface 66b is the surface of the flange portion 66 opposite to the first window member 21.

[0084] The bonding material 25 covers the metallized layer 26 and the plated layer 27 on the side opposite to the internal space S1 (the lower side in FIG. 17) so as not to expose the metallized layer 26 and the plated layer 27. In other words, the edge portions of the metallized layer 26 and the plated layer 27 on the side opposite to the internal space S1 are covered by the bonding material 25 and are not exposed to the outside.

[0085] The bonding material 25 covers the metallized layer 26 and the plating layer 27 so that they are not exposed even on the internal space S1 side (upper side in FIG. 17). That is, the edges of the metallized layer 26 and the plating layer 27 on the internal space S1 side are covered by the bonding material 25 and are not exposed to the outside (internal space S1). The bonding material 25 is also provided so as to reach the end face 65b of the wall portion 65 in the Z direction, and covers the entire end face 65b. In this example, the bonding material 25 extends beyond the end face 65b to the outer surface 65c of the wall portion 65, and covers a portion of the outer surface 65c.

[0086] The bonding material 25 is, for example, a metal brazing material, more specifically, a gold-copper brazing material. The bonding material 25 has a thickness of, for example, several hundred μm. The bonding material 25 is formed, for example, by placing a wire made of metal brazing material at the boundary between the first window member 21 and the first frame member 61 and baking the wire at approximately 1000°C to melt it.

[0087] 18 to 23, the suppression of foreign matter occurring on the window member will be described. For example, when the window member is joined to the housing with a joining material made of silver solder, foreign matter may appear on the window member if the laser excitation light source is continuously driven. Foreign matter on the window member becomes dirt on the window member and can obstruct the transmission of laser light or emitted light, so it is necessary to suppress this.

[0088] Fig. 18 is a photograph showing an example of foreign matter occurring on the first window member 21. Fig. 19 is a photograph showing another example of foreign matter occurring on the first window member 21, where Fig. 19(a) shows the state immediately after the start of operation and Fig. 19(b) shows the state after 46 hours have passed. The samples shown in Figs. 18 and 19 correspond to a configuration in which silver solder is used as the bonding material 25 in the luminous envelope 1 instead of gold-copper solder.

[0089] In Figure 18, the location where foreign matter has occurred is indicated by the symbol P. Foreign matter such as that shown in Figure 18 occurs a relatively long time after drive begins. It is thought that this foreign matter occurs when the silver solder contained in the bonding material moves on the surface of the first window member 21 when the temperature rises due to drive (seepage phenomenon). The seepage phenomenon is thought to occur when the movement of atoms at the bonding surface of the silver solder becomes more intense due to the light output, and the atoms are pushed by internal pressure and gradually move on the surface of the first window member 21.

[0090] As shown in Figures 19(a) and 19(b), no foreign matter was found on the first window member 21 immediately after the start of operation, but foreign matter was found on the first window member 21 after 46 hours had passed. The foreign matter shown in Figure 19(b) appears relatively quickly after the start of operation. It is believed that this foreign matter can be caused by at least one of the following factors. First, the influence of ultraviolet light contained in the second light L2, which is light from the plasma, is considered to be the cause. For example, the ultraviolet light can convert oxygen in the air into ozonation, causing the silver solder contained in the bonding material to oxidize in a short period of time. Another possible cause is the temperature rise of the light-emitting envelope 1 during operation. During operation, the temperature of the light-emitting envelope 1 rises due to irradiation with laser light and radiant heat from the plasma.

[0091] 20(a) to 20(c) are photographs showing the fourth sample immediately after the start of operation, after 147 hours, and after 712 hours, respectively. 21(a) to 21(c) are photographs showing the fifth sample immediately after the start of operation, after 147 hours, and after 712 hours, respectively. 22(a), 22(b), 23(a), and 23(b) are photographs showing the sixth sample immediately after the start of operation, after 168 hours, after 504 hours, and after 1051 hours, respectively. The fourth, fifth, and sixth samples correspond to the luminous envelope 1. As described above, the luminous envelope 1 uses gold-copper solder as the bonding material 25.

[0092] 20 and 21, in the fourth and fifth samples, no foreign matter was generated on the first window member 21 even after 712 hours had passed since the start of driving. As shown in FIGS. 22 and 23, in the sixth sample, no foreign matter was generated on the first window member 21 even after 1051 hours had passed since the start of driving. These results show that the use of a material containing gold as the bonding material 25 can prevent foreign matter from being generated on the first window member 21.

[0093] As described above, in the luminous envelope 1, the first window member 21 is bonded to the housing 10 by the bonding material 25 made of a material containing gold. This reduces the generation of foreign matter on the first window member 21 due to the bonding material 25, compared to when the bonding material 25 is made of silver solder. This is thought to be because using gold, which has a higher melting point than silver solder, as the constituent material of the bonding material 25 prevents the constituent material of the bonding material 25 from moving on the first window member 21 even when the temperature rises due to operation, thereby preventing the occurrence of the seepage phenomenon. Furthermore, because gold is less susceptible to oxidation than silver, it is thought to prevent the constituent material of the bonding material 25 from being oxidized. Therefore, the luminous envelope 1 can prevent the generation of foreign matter on the first window member 21 and improve the lifespan of the luminous envelope 1. The finding that foreign matter can be generated on the first window member 21 due to the constituent material of the bonding material 25 was discovered by the present inventors.

[0094] The housing 10 (first frame member 61) has a wall portion 65 that faces the side surface 21c of the first window member 21, and the bonding material 25 bonds the side surface 21c and the wall portion 65 to each other. This allows the first window member 21 to be reliably bonded to the housing 10. Furthermore, compared to when the first window member 21 is bonded to the housing 10 at the first main surface 21a, for example, a wider area in the first window member 21 through which light passes can be ensured.

[0095] The housing 10 has a flange portion 66 protruding from a wall portion 65, and the first window member 21 is arranged so that the first main surface 21a faces the flange portion 66. This allows the first window member 21 to be securely fixed to the housing 10. It also prevents impurity gases from coming into contact with the joint (metallized layer 26) between the first window member 21 and the housing 10, and prevents the joint from being altered (for example, oxidized) by the impurity gases.

[0096] Bonding material 25 is inserted between first main surface 21a of first window member 21 and flange portion 66. This makes it possible to prevent impurity gases from coming into contact with the joint between first window member 21 and housing 10, and to prevent deterioration of the joint due to impurity gases.

[0097] The bonding material 25 is in a state where it is not bonded to the first main surface 21a of the first window member 21 and is inserted between the first main surface 21a of the first window member 21 and the flange portion 66. As a result, since the bonding material 25 is not bonded to the first main surface 21a of the first window member 21, distortion caused by the difference in thermal expansion coefficient between the first window member 21 and the flange portion 66 can be alleviated.

[0098] The bonding material 25 covers a part of the second surface 66b (the surface opposite to the first window member 21) of the flange portion 66. This makes it possible to suppress the release of impurity gases from the second surface 66b of the flange portion 66.

[0099] The bonding material 25 is provided so as to reach the end surface 65b of the wall portion 65 in the Z direction (the direction perpendicular to the first main surface 21a). This makes it possible to suppress the release of impurity gases from the end surface 65b of the wall portion 65. That is, for example, if the end surface 65b is a metal-processed surface, large irregularities are likely to be formed on the end surface 65b, and impurity gases adsorbed to the irregularities are likely to be released. In this regard, by covering at least a portion of the end surface 65b with the bonding material 25, it is possible to suppress the release of such impurity gases.

[0100] A metallized layer 26 is formed on the first window member 21, a plated layer 27 is formed on the metallized layer 26, and the first window member 21 is joined to the housing 10 by joining the bonding material 25 to the plated layer 27. This allows the first window member 21 to be reliably joined to the housing 10. Furthermore, although the metallized layer 26 has high reactivity, the formation of the plated layer 27 on the metallized layer 26 makes it possible to suppress deterioration of the metallized layer 26 (for example, oxidation).

[0101] The plated layer 27 covers the metallized layer 26 so as not to expose the metallized layer 26. As a result, the metallized layer 26 has high reactivity, but since the plated layer 27 is formed on the metallized layer 26, deterioration of the metallized layer 26 can be suppressed.

[0102] The bonding material 25 covers the metallized layer 26 and the plated layer 27 on the side of the internal space S1 so as not to expose the metallized layer 26 and the plated layer 27. This makes it possible to further suppress deterioration of the metallized layer 26.

[0103] The bonding material 25 covers the metallized layer 26 and the plated layer 27 on the side opposite to the internal space S1 so as to prevent the metallized layer 26 and the plated layer 27 from being exposed. This makes it possible to further suppress deterioration of the metallized layer 26.

[0104] The metallized layer 26 is made of molybdenum manganese. As a result, since molybdenum manganese has a higher melting point than the gold contained in the bonding material 25, it is possible to prevent the constituent material of the metallized layer 26 from diffusing into the bonding material 25 during manufacturing (for example, during baking of the bonding material 25).

[0105] The first window member 21 is made of sapphire. In this case, sapphire has a relatively high transmittance for ultraviolet light, so light containing ultraviolet light can be incident on the first window member 21. However, as described above, when light containing ultraviolet light is incident on the first window member 21, foreign matter is likely to be generated on the first window member 21 due to oxidation of the constituent material of the bonding material 25. In this regard, the luminous envelope 1 can prevent foreign matter from being generated on the first window member 21 even in such cases.

[0106] The bonding material 25 is made of gold-copper solder, which can reliably prevent foreign matter from being generated on the first window member 21.

[0107] The housing 10 has a first frame member 61 fixed to the housing body 11 at the first opening 12, and the first window member 21 is joined to the first frame member 61 by a joining material 25. This allows the first window member 21 to be fixed to the housing 10 in an excellent manner.

[0108] The housing 10 is made of a metal material. In this case, while it is possible to increase the intensity of the second light L2 emitted from the second window portion 30 by increasing the sealing pressure of the luminous gas GS, foreign matter is more likely to be generated on the first window member 21. This is because, as the intensity of the second light L2 increases, the amount of ultraviolet light contained in the second light L2 also increases. In this regard, the luminous envelope 1 can suppress the generation of foreign matter on the first window member 21 even in such cases.

[0109] The pressure of the luminous gas GS enclosed in the housing 10 is 3 MPa or more. In this case, the brightness of the plasma generated in the luminous gas GS can be increased, thereby increasing the intensity of the second light L2 emitted from the second window portion 30. On the other hand, since the temperature of the luminous envelope 1 during operation rises due to an increase in light output, foreign matter is more likely to be generated on the first window member 21. In this regard, the luminous envelope 1 can suppress the generation of foreign matter on the first window member 21 even in such cases.

[0110] As a third modification, the bonding material 25 may be gold-nickel solder. As in the first embodiment, the third modification also makes it possible to prevent foreign matter from being generated on the first window member 21, thereby improving the lifespan of the luminous envelope 1.

[0111] This point will be explained with reference to Figures 24 and 25. Figures 24(a), 24(b), 25(a), and 25(b) are photographs showing the seventh sample immediately after the start of operation, after 168 hours, after 504 hours, and after 1051 hours, respectively. The seventh sample corresponds to the third modified example. As shown in Figures 24 and 25, in the seventh sample, no foreign matter was generated on the first window member 21 even after 1051 hours had passed since the start of operation.

[0112] As a fourth modification, the metallized layer 26 may be made of titanium-doped silver solder. As in the first embodiment, the fourth modification also makes it possible to prevent foreign matter from being generated on the first window member 21, thereby improving the lifespan of the luminous envelope 1.

[0113] This point will be explained with reference to Figures 26 and 27. Figures 26(a), 26(b), 27(a), and 27(b) are photographs showing the eighth sample immediately after the start of operation, after 168 hours, after 504 hours, and after 1051 hours, respectively. The eighth sample corresponds to the third modified example. As shown in Figures 26 and 27, in the eighth sample, no foreign matter was generated on the first window member 21 even after 1051 hours had passed since the start of operation.

[0114] As another modification, although the first window member 21 in the first embodiment was made of sapphire, the first window member 21 may be made of a material other than sapphire, for example, diamond. When the first window member 21 is made of diamond, the metallized layer 26 is preferably made of a material other than molybdenum manganese, and may be, for example, titanium-doped silver solder as in the fourth modification. This is because it is difficult to form the metallized layer 26 made of molybdenum manganese on a window member made of diamond.

[0115] In the first embodiment, the bonding material 25 that bonds the first window member 21 to the housing 10 is formed of a material containing gold. However, in addition to or instead of this, the bonding material 35 that bonds the second window member 31 to the housing 10 (second frame member 71) may be formed of a material containing gold. In this case, it is possible to prevent foreign matter from being generated on the second window member 31, and to improve the life of the luminous envelope 1. That is, at least one of the bonding material 25 and the bonding material 35 may be formed of a material containing gold. As with the second window member 31, a protective layer 80 may be formed on at least the surface (second main surface 21b) of the first window member 21 that faces the internal space S1. In the first embodiment, the first light L1 enters the first opening 12 and the second light L2 exits from the second opening 13. However, one opening may be formed in the housing 10, and the first light L1 enters the opening and the second light L2 exits from the opening. That is, the opening in the housing 10 may be one through which the first light L1 enters and the second light L2 exits. In this case, a window member that transmits the first light L1 and the second light L2 is disposed in the opening. In such a configuration, the window member may be bonded to the housing 10 with a bonding material made of a material containing gold.

[0116] It is only necessary that the first window member 21 and the first frame member 61 (housing 10) are joined by the bonding material 25. For example, the bonding material 25 may be disposed only between the side surface 21c of the first window member 21 and the wall portion 65 of the first frame member 61. In the first embodiment, the first window member 21 is fixed to the housing main body 11 via the first frame member 61. However, the first frame member 61 may be omitted, and the first window member 21 may be fixed directly to the housing main body 11. In this case, for example, the first window member 21 may be disposed in the inner portion 12a of the first opening 12, and a portion of the housing main body 11 that constitutes the inner portion 12a may constitute a wall portion that faces the side surface 21c of the first window member 21, and the side surface 21c and the wall portion may be joined by the bonding material 25. [Sealing part of the sealed tube]

[0117] 1, 3, and 28, the second end 17b of the sealing tube 17 is sealed by being crushed. When the luminous gas GS is sealed into the housing 10, the luminous gas GS is introduced into the housing 10 through the sealing tube 17, and then the second end 17b of the sealing tube 17 is pressed and crushed using a tool or the like, and the sealing tube 17 is pushed through (cut off), thereby sealing the second end 17b (sealing off). As a result, the pipe materials 17b1 constituting the second end 17b come into contact with each other, and the sealing tube 17 is closed at the second end 17b by the sealing tube 17 itself.

[0118] The second end 17b of the sealing tube 17 is covered with a covering member 91. The covering member 91 covers a portion of the sealing tube 17 on the second end 17b side, and covers the entire second end 17b. The covering member 91 is formed in a substantially cylindrical shape, and has a tapered surface 91a on the outer surface of the bottom. The tapered surface 91a is formed so that the diameter becomes smaller the further away from the second end 17b. The covering member 91 functions as a leak prevention member that prevents leakage of the luminous gas GS from the second end 17b.

[0119] The covering member 91 is covered by a cap member 92. The cap member 92 covers the entire surface of the covering member 91 except for a top surface 91b. The top surface 91b is the surface of the covering member 91 opposite to the tapered surface 91a, and is the surface facing the housing 10. The cap member 92 is formed in a substantially cylindrical shape, and has a tapered surface 92a on the inner surface of the bottom. The tapered surface 92a is in contact with the tapered surface 91a, and is formed so that its diameter becomes smaller as it moves away from the second end 17b. The cap member 92 functions as a protective member that protects the second end 17b and the covering member 91.

[0120] The covering member 91 is made of an inorganic material, and the cap member 92 is made of a metal material. In this example, the sealing tube 17 is made of copper, the covering member 91 is made of solder, and the cap member 92 is made of brass. In this case, the thermal expansion coefficient of the sealing tube 17 is 17.7×10 -6 (1 / K), and the thermal expansion coefficient of the covering member 91 is 20.2×10-6 (1 / K), and the thermal expansion coefficient of the cap member 92 is 18.0×10 -6 (1 / K). That is, in this example, the coefficient of thermal expansion is greatest in the order of covering member 91, cap member 92, and sealing tube 17. The hardness (Vickers hardness) of sealing tube 17 is 70 to 80 HV, the hardness of covering member 91 is about 20, and the hardness of cap member 92 is about 180 to 230 HV. That is, in this example, the hardness is greatest in the order of cap member 92, sealing tube 17, and covering member 91.

[0121] As described above, in the luminous envelope 1, the second end 17b of the sealed tube 17, which is crushed and sealed, is covered with the covering member 91 made of an inorganic material. This prevents the second end 17b from opening, and even if a leak occurs from the second end 17b, it prevents a decrease in the pressure of the luminous gas GS enclosed in the housing 10. Furthermore, because the covering member 91 is made of an inorganic material, it can stably cover the second end 17b even in a high-temperature environment. Furthermore, in the luminous envelope 1, the covering member 91 is covered with the cap member 92 made of a metal material. This protects the second end 17b and the covering member 91. Furthermore, when the temperature rises, the covering member 91 can be easily deformed toward the second end 17b rather than the cap member 92. As a result, the covering member 91 can hold down the second end 17b, further preventing the second end 17b from opening. Therefore, the luminous envelope 1 can suppress leakage of the luminous gas GS caused by the opening of the second end 17b of the sealing tube 17, thereby improving the life of the luminous envelope 1. In a laser excitation light source, the luminous gas is sometimes sealed at high pressure to achieve high efficiency and high output, and the temperature rises during operation due to irradiation with laser light and radiant heat from the plasma. Therefore, if the laser excitation light source is continuously driven for a long period of time, the sealed end of the sealing tube may be forced open, potentially causing leakage of the luminous gas. In contrast, the luminous envelope 1 can suppress leakage of the luminous gas GS caused by the opening of the second end 17b of the sealing tube 17, as described above, thereby improving the life of the luminous envelope 1.

[0122] The thermal expansion coefficient of the covering member 91 is greater than the thermal expansion coefficient of the sealed tube 17. This allows the covering member 91 to effectively hold down the second end 17b of the sealed tube 17 when the temperature rises, further preventing the second end 17b from opening.

[0123] The hardness of cap member 92 is greater than the hardness of sealing tube 17. This makes it easier for covering member 91 to deform toward second end 17b rather than toward cap member 92 when the temperature rises, thereby further preventing second end 17b from opening.

[0124] The covering member 91 is made of a thermoplastic material (solder in the above example), which can preferably achieve the above-mentioned advantageous effects that the second end 17b can be prevented from opening, that the pressure of the luminous gas GS enclosed in the housing 10 can be prevented from decreasing even if a leak occurs from the second end 17b, and that the second end 17b can be stably covered even in a high-temperature environment.

[0125] The cap member 92 is made of brass, which preferably provides the above-mentioned advantageous effects that the second end 17b and the covering member 91 can be protected, and that the covering member 91 can hold down the second end 17b, thereby further preventing the second end 17b from opening.

[0126] The pressure of the luminous gas GS enclosed in the housing 10 is 3 MPa or more. In this case, the intensity of the plasma generated in the luminous gas GS can be increased, but the second end 17b of the enclosed tube 17 is likely to open. However, the luminous envelope 1 can prevent the second end 17b from opening even in such a case.

[0127] The materials of the sealing tube 17, the covering member 91 and the cap member 92 are not limited to the examples described above, and may be made of any material. [Second embodiment]

[0128] As shown in FIGS. 29 to 32, the light-emitting envelope 1A according to the second embodiment further includes a getter portion 101. FIG. 29 shows the getter portion 101 in a schematic manner. In the light-emitting envelope 1A, the protective layer 80 is not formed on the second window member 31. The getter portion 101 includes a getter material 110 and a support member 120 that supports the getter material 110. The getter material 110 is activated by heating and adsorbs impurity gases present in the internal space S1. The getter material 110 is formed of a material containing, for example, nichrome, and is configured to be non-evaporable. That is, in this example, the getter material 110 does not evaporate when heated and activated. The getter material 110 is activated by heating to, for example, 250° C. or higher. The getter material 110 is formed in the shape of, for example, a rectangular plate.

[0129] The support member 120 is formed of, for example, a metal material in the shape of a rectangular plate having an outer shape larger than that of the getter material 110. Examples of metal materials constituting the support member 120 include high-melting-point metals such as tungsten and molybdenum.

[0130] The getter material 110 is placed on a support member 120 and fixed to the support member 120 by three fixing members 121. The fixing members 121 are formed in a strip (ribbon) shape, for example, from nickel. The fixing members 121 are placed so as to press down on the getter material 110 at their middle portions, and are fixed to the support member 120 at both ends by, for example, welding. In this way, the getter material 110 is fixed to the support member 120. In FIG. 30, the getter material 110 is hatched to make it easier to understand.

[0131] The support member 120 is fixed to the housing main body 11 (housing 10) by four fixing members 122. The fixing members 122 are formed in a strip (ribbon) shape from, for example, nickel. The fixing members 122 have extending portions 122a that extend perpendicularly to the support member 120 from the corners of the support member 120. The extending portions 122a are fixed to the housing main body 11 by, for example, welding. The fixing members 122 are also fixed to the support member 120 by, for example, welding. In this way, the support member 120 is fixed to the housing main body 11.

[0132] The getter section 101 is disposed within an irradiation region RG of the first light L1 within the housing 10. FIG. 29 shows the irradiation region RG of the first light L1. As shown in FIG. 29, the first light L1 transmitted through the first window section 20 converges so that its focus is located on, for example, an intersection C of the first optical axis A1 and the second optical axis A2 (the position where the second light L2 is generated). The first light L1 that has passed through the intersection C spreads and travels in the opposite direction from the first window section 20 (upper side in FIG. 29). In this example, the getter section 101 (the getter material 110 and the support member 120) is disposed on the first optical axis A1 of the first light L1.

[0133] The getter section 101 is arranged so that the getter material 110 faces the opposite side (upper side in FIG. 29) from the first window section 20. As a result, the support member 120 is arranged so as to face the first window section 20 side, and the first light L1 is irradiated onto the support member 120. In the luminous envelope 1A, the support member 120 is heated by irradiation with the first light L1, and the getter material 110 is indirectly heated by the averaged heat transferred from the support member 120.

[0134] The getter section 101 is arranged so that the getter material 110 faces the inner surface 10a of the housing 10. The inner surface 10a is the surface of the housing 10 that faces the first window section 20. Here, the inner surface 10a facing the first window section 20 means that the inner surface 10a and the first window section 20 overlap in the Z direction (a direction parallel to the first optical axis A1), and other members may be arranged between the inner surface 10a and the first window section 20. In this example, the inner surface 10a has a tapered shape whose diameter decreases as it moves away from the getter section 101.

[0135] The getter section 101 is disposed so as to define a space S2 between itself and the inner surface 10a. The space S2 is a part of the internal space S1. In this example, the space S2 is a substantially conical space whose diameter decreases with increasing distance from the getter section 101. The space S2 is not completely separated by the getter section 101, and is connected to the part of the internal space S1 other than the space S2 via a minute gap.

[0136] The getter portion 101 is disposed in the internal space S1 between the generation position of the second light L2 (intersection C of the first optical axis A1 and the second optical axis A2) and the sealing hole 16. As described above, the sealing hole 16 also functions as an exhaust hole for discharging gas (impurity gas) from the internal space S1 to the outside during the manufacture of the light-emitting envelope 1. The distance D1 from the getter material 110 to the generation position of the second light L2 is longer than the distance D2 from the generation position of the second light L2 to the first window portion 20.

[0137] The melting point of the support member 120 is higher than that of the getter material 110. As an example, the getter material 110, the support member 120, the housing body 11, and the first frame member 61 (second frame member 71) are made of nichrome, tungsten, SUS304, and Kovar metal, respectively. The melting points of nichrome, tungsten, SUS304, and Kovar metal are 1400°C, 3387°C, 1400-1450°C, and 1450°C, respectively. That is, in this example, the melting point of the support member 120 is higher than that of the getter material 110, the housing body 11, and the first frame member 61. Even when the support member 120 is made of molybdenum, the melting point of molybdenum is 2623°C, so the melting point of the support member 120 is higher than that of the getter material 110, the housing body 11, and the first frame member 61.

[0138] The thermal conductivity of the support member 120 is higher than that of the getter material 110. The thermal conductivities of nichrome, tungsten, SUS304, and Kovar metal are 14 (W / m·K), 168 (W / m·K), 16.7 (W / m·K), and 17 (W / m·K), respectively. That is, in an example in which the getter material 110, the support member 120, the housing main body 11, and the first frame member 61 (second frame member 71) are made of nichrome, tungsten, SUS304, and Kovar metal, respectively, the thermal conductivity of the support member 120 is higher than that of the getter material 110, the housing main body 11, and the first frame member 61. Even when the support member 120 is made of molybdenum, the thermal conductivity of molybdenum is 142 (W / m·K), so the thermal conductivity of the support member 120 is higher than the thermal conductivity of the getter material 110, the housing main body 11, and the first frame member 61.

[0139] When the luminous envelope 1A is driven, in the first step, the getter material 110 is heated and activated by irradiation with the first light L1 through the first window 20. Then, in the second step, with the getter material 110 activated, plasma is generated in the luminous gas GS and the second light L2 is emitted from the second window 30. This allows the activated getter material 110 to adsorb impurity gases present in the internal space S1. Note that the first and second steps may be performed sequentially as in this example, or may be performed simultaneously.

[0140] Next, we will explain how to suppress defects caused by the getter section 101. In a laser pumped light source, if impurity gases are present in the internal space of the housing, various defects may occur within the housing depending on the driving conditions. In order to improve the life of the laser pumped light source, it is necessary to suppress the occurrence of such defects.

[0141] One of the problems caused by impure gases is the phenomenon in which the window material becomes opaque (opacity phenomenon) mentioned above (Figure 6).

[0142] Another problem caused by impure gases is the generation of foreign matter within the housing 10. FIGS. 33(a) and 33(b) are photographs showing examples of foreign matter on the first electrode 40 and / or the second electrode 50. In the photograph shown in FIG. 33(a), foreign matter is attached to the tips of the first electrode 40 and the second electrode 50, as indicated by the arrows AR. This foreign matter is primarily composed of, for example, carbon. In the photograph shown in FIG. 33(b), foreign matter is attached to the side surface of the second electrode 50, as indicated by the arrows AR. This foreign matter is composed of, for example, tungsten oxide. These foreign matters are thought to be generated due to impure gases present in the internal space S1 within the housing 10. These foreign matters may impair the operation of the luminous envelope 1A, and therefore, their suppression is desirable.

[0143] 34(a) to 34(c) are photographs showing the ninth sample immediately after the start of operation, after 260 hours, and after 670 hours, respectively. The ninth sample corresponds to a configuration in which the getter section 101 is not provided in the luminous envelope 1A. As shown in FIG. 34(a), no foreign matter was attached to the first electrode 40 and the second electrode 50 immediately after the start of operation. As indicated by arrows AR in FIGS. 34(b) and 34(c), foreign matter was attached to the first electrode 40 and the second electrode 50 after 260 hours and 670 hours.

[0144] 35 to 37 are photographs showing the tenth sample immediately before the start of operation, immediately after the start of operation, and 165 hours later, respectively. The first window portion 20 is shown in FIGS. 35(a) to 37. The focus is on the first window member 21 in FIG. 35(a), the focus is on the first electrode 40 and the second electrode 50 in FIG. 35(b), and the focus is on the support member 120 in FIG. 35(c). This is also true for FIGS. 36 and 37. The tenth sample corresponds to the luminous envelope 1A. As shown in FIGS. 35 to 37, even after 165 hours had passed since the start of operation, the first window member 21 did not become opaque, and no foreign matter was found on the first electrode 40 or the second electrode 50.

[0145] 38 to 40 are photographs showing the 11th sample immediately before the start of operation, immediately after the start of operation, and 165 hours after the start of operation, respectively. FIGS. 41 to 43 are photographs showing the 12th sample immediately before the start of operation, immediately after the start of operation, and 165 hours after the start of operation, respectively. FIGS. 38 to 43 show the second window portion 30. In FIG. 38(a), the focus is on the second window member 31. In FIG. 38(b), the first electrode 40 and the second electrode 50 are photographed through the second window member 31, with the focus on the first electrode 40 and the second electrode 50. These points are also true for FIGS. 39 to 44. The 11th and 12th samples correspond to the luminous envelope 1A. As shown in FIGS. 38 to 43, in both the 11th and 12th samples, even 165 hours after the start of operation, the second window member 31 did not become opaque, and no foreign matter was found on the first electrode 40 or the second electrode 50.

[0146] Fig. 44(a) is a photograph showing the 13th sample immediately after the start of operation, and Fig. 44(b) is a photograph showing the 13th sample after 262 hours have passed. The 13th sample corresponds to the luminous envelope 1A. As shown in Fig. 44, even after 165 hours had passed since the start of operation, no foreign matter was found to be attached to the first electrode 40 or the second electrode 50.

[0147] From the above results, it can be seen that the provision of getter section 101 makes it possible to suppress the occurrence of the opacifying phenomenon and the generation of foreign matter within housing 10.

[0148] As described above, in the luminous envelope 1A, the getter section 101 having the getter material 110 is disposed within the irradiated region RG of the first light L1 within the casing 10. This allows the getter material 110 to be heated and activated by irradiation with the first light L1, and the activated getter material 110 can adsorb impurity gases present in the internal space S1. As a result, the occurrence of defects due to impurity gases can be suppressed. Furthermore, since the getter material 110 is heated and activated by irradiation with the first light L1, heating of components other than the getter section 101, such as the casing 10, can be suppressed. As a result, for example, the occurrence of defects due to a rise in temperature of the casing 10 (such as leakage of the luminous gas GS) can be suppressed. Therefore, the luminous envelope 1A can improve its lifespan.

[0149] The getter section 101 has a support member 120 that supports the getter material 110. This allows the getter material 110 to be indirectly heated via the support member 120, for example, and makes it possible to prevent the getter material 110 from being excessively heated.

[0150] The getter portion 101 is arranged so that the getter material 110 faces away from the first window portion 20. This allows the support member 120 to function as an adhesion prevention plate, and can prevent the scattered (sputtered) getter material 110 from moving toward the first window portion 20 and adhering to the first window portion 20, etc.

[0151] The getter section 101 is arranged so that the first light L1 is irradiated onto the support member 120. This allows the getter material 110 to be indirectly heated via the support member 120, and makes it possible to prevent the getter material 110 from being heated excessively.

[0152] The melting point of the support member 120 is higher than the melting point of the getter material 110. This makes it possible to prevent the support member 120 from being damaged by heating caused by irradiation with the first light L1.

[0153] The thermal conductivity of the support member 120 is higher than the thermal conductivity of the getter material 110. This allows the getter portion 101 to be heated efficiently via the support member 120.

[0154] The getter section 101 is arranged so that the getter material 110 faces the inner surface 10a of the housing 10, which faces the first window section 20. This allows the scattered getter material 110 to adhere to the inner surface 10a. The getter material 110 adhered to the inner surface 10a can be heated again by the first light L1 and activated. As a result, the getter material 110 adhered to the inner surface 10a can also adsorb impurity gases.

[0155] The getter section 101 is arranged so as to define a space S2 between itself and the inner surface 10a of the housing 10. This allows the scattered getter material 110 to be contained within the space S2, and prevents the getter material 110 from adhering to other members.

[0156] The getter portion 101 is disposed in the internal space S1 between the generation position of the second light L2 (intersection C of the first optical axis A1 and the second optical axis A2) and the sealing hole 16 (exhaust hole). Gas may be generated from the getter material 110 during the manufacture of the luminous envelope 1A, but the luminous envelope 1A makes it possible to easily exhaust the gas from the sealing hole 16 to the outside.

[0157] A distance D1 from the getter material 110 to the generation position of the second light L2 is longer than a distance D2 from the generation position of the second light L2 to the first window portion 20. This makes it possible to prevent the getter material 110 from being excessively heated.

[0158] The getter material 110 is configured to be non-evaporative. In this case, it is possible to suppress the occurrence of problems caused by impure gases and improve the life of the light-emitting envelope 1A. The amount of the non-evaporative getter material 110 may be determined taking into consideration the degree of vacuum, life, etc. of the light-emitting envelope 1A.

[0159] The second window portion 30 has a second window member 31 made of a material containing diamond. In this case, light of a wide wavelength range, including ultraviolet light, can pass through. Furthermore, although impurity gases tend to cause the generation of foreign matter containing carbon, the luminous envelope 1A can suppress the generation of foreign matter even in such cases.

[0160] The housing 10 is made of a metal material. In this case, the pressure of the luminous gas GS can be increased, and the intensity of the second light L2 emitted from the second window 30 can be increased. As described above, impurity gases are likely to be present in the internal space S1, but the luminous envelope 1A can suppress the occurrence of problems caused by impurity gases even in such cases.

[0161] The luminous envelope 1A includes a first electrode 40 and a second electrode 50 that face each other across the position where the second light L2 is generated. In this case, plasma can be generated more reliably. Furthermore, although foreign matter caused by impure gases is likely to be generated on the first electrode 40 and the second electrode 50, the luminous envelope 1A can prevent foreign matter from being generated on the first electrode 40 and the second electrode 50.

[0162] The pressure of the luminous gas GS enclosed in the housing 10 is 3 MPa or more. In this case, as described above, the brightness of the plasma generated in the luminous gas GS can be increased, and thereby the intensity of the second light L2 emitted from the second window portion 30 can be increased. On the other hand, impurity gases are more likely to be present in the housing 10. In this regard, the luminous envelope 1A can suppress the occurrence of problems caused by impurity gases even in such cases.

[0163] The method for operating the luminous envelope 1A according to the second embodiment includes the steps of activating the getter material 110 by irradiating it with a first light L1 and generating plasma in the luminous gas GS and emitting a second light L2. In this driving method, the getter material 110 can be heated and activated by irradiating it with the first light L1, and the activated getter material 110 can adsorb impurity gases present in the internal space S1. As a result, it is possible to suppress the occurrence of defects caused by impurity gases and improve the life of the luminous envelope 1A.

[0164] As in a fifth modified example shown in FIG. 45, the getter material 110 may be fixed to the inner surface of the housing 10. In FIG. 45, the getter material 110 is hatched for ease of understanding. In the fifth modified example, the getter section 101 has only the getter material 110 and does not have a support member 120 or the like. The inner surface of the housing 10 has a cylindrical inner circumferential surface 10b extending with a straight line parallel to the first optical axis A1 of the first light L1 as its center line. The getter material 110 is fixed to the inner circumferential surface 10b. The getter material 110 extends in the circumferential direction so as to form a cylindrical shape (annular belt shape) as a whole, but may have a gap (gap) in part in the circumferential direction. In the fifth modified example, the getter material 110 is also arranged within the irradiation region RG of the first light L1. More specifically, the getter material 110 is disposed so that the skirt of the first light L1, which is a laser beam, is incident on the getter material 110, and is directly heated by irradiation with the first light L1.

[0165] According to the fifth modification, as in the second embodiment, it is possible to suppress the occurrence of defects caused by impure gases and improve the life of the luminous envelope 1A. In addition, the getter material 110 can be heated using the tail of the first light L1, which is a laser beam. Therefore, it is possible to suppress the occurrence of defects caused by impure gases while suppressing the getter material 110 from being excessively heated.

[0166] In the sixth modified example shown in FIG. 46, the getter material 110 is configured as an evaporation type (deposition type). The evaporation type getter material 110 is formed of a material containing barium, for example. When the evaporation type getter material 110 is heated and activated, at least a portion of it evaporates (the barium is ejected). The evaporated getter material 110 is deposited on the inner surface 10a of the housing 10. The deposited getter material 110 forms an adsorption surface for impurity gases. When the light-emitting envelope 1A starts to operate, the getter material 110 is heated by irradiation with the first light L1 and is deposited on the inner surface 10a. Thereafter, plasma is generated and a portion of the first light L1 is absorbed by the plasma, thereby easing the heating of the getter material 110 and stopping the deposition. Since the getter material 110 is heated and a new adsorption surface is formed each time the light-emitting envelope 1A is operated, the adsorption surface can be maintained in a good condition each time the light-emitting envelope 1A is operated. As with the second embodiment, this sixth modification can also suppress the occurrence of defects caused by impurity gases and improve the lifespan of the luminous envelope 1A. The amount of evaporative getter material 110 can be determined taking into consideration the degree of vacuum and lifespan of the luminous envelope 1A. It is not necessary to determine the amount of getter material 110 so that the getter material 110 is heated and a new adsorption surface is formed every time the luminous envelope 1A is driven. For example, the getter material 110 may be heated and a new adsorption surface is formed only during the first drive and several subsequent drives, when the amount of impurity gas released is expected to be particularly large. In this case, the support member 120, free of the getter material 110, has the effect of shielding and protecting the getter material 110 deposited on the inner surface 10a of the housing 10 from the first light L1.

[0167] As another modification, in the second embodiment, the getter material 110 may be disposed at any position other than the above-described position as long as it is disposed within the irradiation region RG of the first light L1. It is sufficient that at least a portion of the getter material 110 is disposed within the irradiation region RG. For example, the support member 120 may be disposed within the irradiation region RG, while the getter material 110 is disposed outside the irradiation region RG. The getter material 110 may be disposed facing the first window portion 20. In this case, the getter material 110 is directly heated by irradiation with the first light L1. The distance D1 from the getter material 110 to the generation position of the second light L2 may be shorter than the distance D2 from the generation position of the second light L2 to the first window portion 20. In this case, the getter material 110 can be efficiently heated by irradiation with the first light L1. In the luminous envelope 1A of the second embodiment, a protective layer 80 may be formed on the second window member 31. In this case, the occurrence of the opacification phenomenon can be further suppressed. The materials of the getter material 110 and the support member 120 are not limited to the examples described above, and may be made of any material.

[0168] The present invention is not limited to the above-described embodiment and modified examples. For example, the materials and shapes of each component are not limited to those described above, and various materials and shapes can be used. The shapes of the first opening 12, the second opening 13, the first window member 21, and the second window member 31 are not limited to circular plates, and may be various shapes. While two second openings 13 are formed in the above-described example, only one second opening 13 may be formed, or three or more second openings 13 may be formed. As described above, the first light L1 may enter and the second light L2 may exit through one opening formed in the housing 10. The material constituting the housing 10 does not necessarily have to be a metal material, but may also be an insulating material, such as ceramic. The first electrode 40 and the second electrode 50 may be omitted. Even in this case, plasma can be generated at the focus by irradiating the light-emitting gas GS with the concentrated first light L1.

[0169] The first window member 21 may be made of diamond, and the second window member 31 may be made of sapphire. Alternatively, both the first window member 21 and the second window member 31 may be made of sapphire or diamond. When ultraviolet light is used, the first window member 21 and / or the second window member 31 may be made of magnesium fluoride or quartz. The first window member 21 and / or the second window member 31 may be made of Kovar glass. The first window member and the second window member may be configured to be the same window member. That is, the first light L1 and the second light L2 may be configured to pass through the same window member. The first window member, the second window member, and the housing 10 may be integrally formed of a translucent material. In this case, the region of the translucent region of the housing 10 through which the first light L1 passes can be considered as the first window member (first window portion), and the region through which the second light L2 passes can be considered as the second window member (second window portion). When the first window member 21 is made of diamond, a protective layer 80 may be formed on the surface (second main surface 21b) of the first window member 21 facing the internal space S1. The protective layer 80 may not be formed on the second window member 31. The bonding material 25 may be titanium-doped silver solder. The second end 17b of the sealing tube 17 may not be covered by the covering member 91 and the capping member 92. That is, at least one of the covering member 91 and the capping member 92 may be omitted. In this specification, "A and / or B" means "at least one of A and B." [Explanation of symbols]

[0170] 1, 1A...luminous envelope, 10...housing, 20...first window portion, 30...second window portion, 35...bonding material, 71...second frame member, 80...protective layer, 81...first layer (first ALD layer), 82...second layer (second ALD layer), 83...ALD layer, GS...luminous gas, L1...first light, L2...second light, S1...internal space.

Claims

1. A housing containing a luminous gas in an internal space; a first window portion provided in the housing, through which a first light, which is a laser light for maintaining plasma generated in the light-emitting gas, enters; a second window provided in the housing through which a second light, which is light from the plasma, exits; At least one of the first window portion and the second window portion has a window member made of a material containing diamond, A protective layer made of an inorganic material is formed on at least a surface of the window member facing the internal space.

2. The luminescent envelope of claim 1 , wherein the protective layer comprises multiple layers.

3. 3. The luminescent envelope according to claim 1, wherein the protective layer contains a material having a lower transmittance for ultraviolet light than diamond.

4. The luminescent envelope according to claim 1 or 2, wherein the protective layer contains a material having a higher transmittance for ultraviolet light than diamond.

5. The luminescent envelope of any one of claims 1 to 4, wherein the protective layer comprises an ALD layer.

6. The luminescent envelope of any one of claims 1 to 5, wherein the protective layer comprises a first ALD layer of a first material and a second ALD layer of a second material different from the first material.

7. The protective layer is made of Al ２ O ３ The luminescent envelope of any one of claims 1 to 6, comprising a layer consisting of:

8. The protective layer is made of SiO ２ The luminescent envelope of any one of claims 1 to 6, comprising a layer consisting of:

9. The protective layer is made of TiO ２ The luminescent envelope of any one of claims 1 to 6, comprising a layer consisting of:

10. The protective layer is made of Al ２ O ３ 10. The luminescent envelope of claim 1, comprising a layer consisting of:

11. The protective layer is made of Al ２ O ３ A first layer made of SiO ２ and a second layer consisting of

12. The protective layer is made of Al ２ O ３ A first layer consisting of TiO ２ and a second layer consisting of

13. The luminescent envelope of any one of claims 10 to 12, wherein the protective layer consists of one or more ALD layers.

14. The luminous envelope according to any one of claims 1 to 13, wherein the housing is made of a metal material.

15. the window member is fixed to a frame member formed of a metal material and is fixed to the housing via the frame member, The luminous envelope according to any one of claims 1 to 14, wherein the protective layer is formed so as to extend from above the window member to above the frame member.

16. the window member is fixed to the frame member by a bonding material, The luminescent envelope of claim 15 , wherein the protective layer covers the bonding material.

17. The luminescent envelope according to any one of claims 1 to 16, wherein the pressure of the luminescent gas enclosed in the housing is 3 MPa or more.

18. A luminescent envelope according to any one of claims 1 to 17; a light introducing portion that allows the first light to enter the first window portion.

Images