Flash discharge tube, phototherapy device, and method for manufacturing flash discharge tube

Abstract

A flash discharge tube (1) is provided with: a light-transmissive envelope (10) in which an inert gas is enclosed; an anode (20); and a cathode (30). The envelope (10) includes: a quartz glass tube (11); a borosilicate glass material (12) that seals the anode (20); a borosilicate glass material (13) that seals the cathode (30); an intermediate glass material (14) that is disposed between the quartz glass tube (11) and the borosilicate glass material (12), and joins the quartz glass tube (11) and the borosilicate glass material (12); and an intermediate glass material (15) that is disposed between the quartz glass tube (11) and the borosilicate glass material (13), and joins the quartz glass tube (11) and the borosilicate glass material (13). Each of the intermediate glass materials (14, 15) is a glass material consisting of one stage or two stages. The tip portion of the cathode (30) is positioned inside the quartz glass tube (11). The cathode (30) has a sintered pellet (34). The sintered pellet (34) overlaps the intermediate glass material (15) in a side view of the quartz glass tube (11).

Description

Flash discharge tube, phototherapy device, and method for manufacturing a flash discharge tube

[0001] The present invention relates to a flash discharge tube, a phototherapy device, and a method for manufacturing a flash discharge tube.

[0002] Patent Document 1 discloses a flash discharge tube comprising a first glass tube made of quartz glass, a second glass tube made of borosilicate glass, and a stepped glass tube positioned between the first and second glass tubes. The stepped glass tube has a thermal expansion coefficient between the thermal expansion coefficient of the first glass tube and the thermal expansion coefficient of the second glass tube.

[0003] Japanese Patent Publication No. 2012-119205

[0004] There is room for improvement regarding the light emission durability of the flash discharge tube disclosed in Patent Document 1.

[0005] Therefore, the present invention aims to provide a flash discharge tube with high light emission durability, a phototherapy device equipped with the flash discharge tube, and a method for manufacturing the flash discharge tube.

[0006] A flash discharge tube according to one aspect of the present invention comprises a translucent enclosure with an inert gas sealed inside, an anode disposed at one end of the enclosure, and a cathode disposed at the other end of the enclosure, wherein the enclosure comprises a quartz glass tube, a first borosilicate glass material disposed at one end of the quartz glass tube and sealing the anode, a second borosilicate glass material disposed at the other end of the quartz glass tube and sealing the cathode, and a second borosilicate glass material disposed between the quartz glass tube and the first borosilicate glass material The glass includes a first intermediate glass material that joins the acid glass material, and a second intermediate glass material that is placed between the quartz glass tube and the second borosilicate glass material and joins the quartz glass tube and the second borosilicate glass material, wherein the first intermediate glass material and the second intermediate glass material are glass materials consisting of one or two layers, the tip of the cathode is located inside the quartz glass tube, the cathode has a sintered body, and the sintered body overlaps the second intermediate glass material when viewed from a direction perpendicular to the axial direction of the quartz glass tube.

[0007] A phototherapy device according to one aspect of the present invention comprises a flash discharge tube according to the above aspect.

[0008] A method for manufacturing a flash discharge tube according to an aspect of the present invention includes a step of hermetically sealing a glass bead made of borosilicate glass to the tungsten rod of an anode including the tungsten rod, a step of welding an intermediate glass material to one end of a quartz glass tube, and a step of hermetically sealing the intermediate glass material and the glass bead in a state where the tungsten rod is inserted into a through hole provided in the intermediate glass material.

[0009] According to the present invention, it is possible to provide a flash discharge tube having high emission durability, a phototherapy device including the flash discharge tube, and a method for manufacturing the flash discharge tube.

[0010] FIG. 1 is a side view of a flash discharge tube according to an embodiment. FIG. 2 is a side view showing the attachment position of a trigger winding of the flash discharge tube according to the embodiment. FIG. 3 is a side view showing an enlarged view of the vicinity of the cathode of the flash discharge tube according to the embodiment. FIG. 4 is a side view of the anode of the flash discharge tube according to the embodiment. FIG. 5 is a side view of the cathode of the flash discharge tube according to the embodiment. FIG. 6 is a side view for explaining a step of a method for manufacturing a flash discharge tube according to the embodiment. FIG. 7 is a side view for explaining a step of a method for manufacturing a flash discharge tube according to the embodiment. FIG. 8 is a side view for explaining a step of a method for manufacturing a flash discharge tube according to the embodiment. FIG. 9 is a side view for explaining a step of a method for manufacturing a flash discharge tube according to the embodiment. FIG. 10 is a side view showing an enlarged view of the vicinity of the cathode of a flash discharge tube according to Modification 1 of the embodiment. FIG. 11 is a side view showing an enlarged view of the vicinity of the cathode of a flash discharge tube according to Modification 2 of the embodiment. FIG. 12 is a side view showing an enlarged view of the vicinity of the cathode of a flash discharge tube according to Modification 3 of the embodiment. FIG. 13 is a side view showing an enlarged view of the vicinity of the cathode of a flash discharge tube according to Modification 4 of the embodiment. FIG. 14 is a view showing the appearance of a phototherapy device including the flash discharge tube according to the embodiment.

[0011] Hereinafter, the flash discharge tube, the light therapy device, and the method for manufacturing the flash discharge tube according to the embodiments of the present invention will be described in detail with reference to the drawings. Note that each of the embodiments described below shows a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, arrangements of components, connection forms, manufacturing processes, order of manufacturing processes, etc. shown in the following embodiments are merely examples and are not intended to limit the present invention. Thus, among the components in the following embodiments, the components not described in the independent claims are described as optional components.

[0012] In addition, each drawing is a schematic diagram and is not necessarily drawn precisely. Therefore, for example, the scales in each drawing do not necessarily match. Also, in each drawing, substantially the same components are denoted by the same reference numerals, and overlapping descriptions are omitted or simplified.

[0013] In this specification, terms indicating the relationship between elements, terms indicating the shape of elements, and numerical ranges are not expressions representing only strict meanings, but are expressions meaning substantially equivalent ranges, for example, including differences of about several percent.

[0014] In this specification, "translucency" means the property of transmitting at least a part of the incident light. For example, a member having translucency can transmit light with an intensity greater than 50% of the intensity of the light incident on the member.

[0015] In this specification, the "main component" means the component having the highest content rate among all the components constituting the member. For example, a component having a content rate of 50% or more is the main component. The component is a material, an element, a compound, or the like. Also, "member A is made of component B" or "member A is composed of component B" means that member A substantially contains only component B. However, member A may contain impurities that are unavoidably mixed in during manufacturing in addition to component B.

[0016] In this specification, ordinal numbers such as "first" and "second" do not mean the number or order of components unless otherwise specified, and are used for the purpose of avoiding confusion and distinguishing between the same type of components.

[0017] (Embodiment) [Configuration] First, the configuration of the flash discharge tube according to the embodiment will be explained using Figures 1 to 5.

[0018] Figure 1 is a side view of the flash discharge tube 1 according to this embodiment. Figure 2 is a side view showing the mounting position of the trigger winding 40 of the flash discharge tube 1 according to this embodiment. Figure 3 is a magnified side view showing the vicinity of the cathode 30 of the flash discharge tube 1 according to this embodiment. Figure 4 is a side view of the anode 20 of the flash discharge tube 1 according to this embodiment. Figure 5 is a side view of the cathode 30 of the flash discharge tube 1 according to this embodiment.

[0019] As shown in Figure 1, the flash discharge tube 1 comprises an enclosure 10, an anode 20, and a cathode 30. The anode 20 and cathode 30 are a pair of discharge electrodes provided in the flash discharge tube 1. The anode 20 is located at one end of the enclosure 10 in the axial direction. The cathode 30 is located at the other end of the enclosure 10 in the axial direction. Furthermore, as shown in Figure 2, the flash discharge tube 1 includes a trigger winding 40.

[0020] [Enclosure] First, the specific configuration of the enclosure 10 will be explained using Figure 1.

[0021] The enclosure 10 is a translucent enclosure with an inert gas sealed inside. The inert gas is specifically a noble gas, such as xenon gas. The inert gas may also be argon gas or krypton gas, etc. The inert gas may be a single gas or a mixture of gases.

[0022] The outer enclosure 10 includes a quartz glass tube 11, borosilicate glass materials 12 and 13, and intermediate glass materials 14 and 15.

[0023] The quartz glass tube 11 is a tubular member having a space inside inert gas. The shape of the quartz glass tube 11 is a cylindrical straight tube. The outer diameter of the quartz glass tube 11 is, for example, 3 mm or more and 6 mm or less, with 4.0 mm as an example. The inner diameter of the quartz glass tube 11 is, for example, 1.0 mm or more and 4.0 mm or less, with 2.35 mm as an example. The axial length of the quartz glass tube 11 is, for example, 15 mm or more and 60 mm or less. However, the shape and size of the quartz glass tube 11 are not particularly limited.

[0024] In this embodiment, the quartz glass tube 11 does not have any traces of inert gas sealing. A sealing trace refers to the mark left when an opening, which is provided through the side of the glass tube to serve as an inlet or outlet for the gas, is sealed. The sealing trace can be formed as a recess or protrusion on the side of the glass tube. Since there are no sealing traces, the inner and outer diameters of the quartz glass tube 11 are substantially uniform.

[0025] The borosilicate glass materials 12 and 13 are arranged at both ends of the quartz glass tube 11. Specifically, borosilicate glass material 12 is an example of the first borosilicate glass material and is arranged at one end in the axial direction of the quartz glass tube 11 to seal the anode 20. Borosilicate glass material 13 is an example of the second borosilicate glass material and is arranged at the other end in the axial direction of the quartz glass tube 11 to seal the cathode 30. The borosilicate glass materials 12 and 13 are in close contact with the anode 20 or cathode 30 without any gaps, so that the internal space and external space of the enclosure 10 do not communicate with each other. In this embodiment, the borosilicate glass material 12 and the borosilicate glass material 13 have different shapes. Specifically, borosilicate glass material 12 is smaller than borosilicate glass material 13. More specifically, the maximum outer diameter of the borosilicate glass material 12 is smaller than the maximum outer diameter of the borosilicate glass material 13.

[0026] The borosilicate glass material 12 is a so-called glass bead. The borosilicate glass material 12 is joined to the outer end of the intermediate glass material 14. The second glass material 142 of the intermediate glass material 14 and the borosilicate glass material 12 are welded to each other. The maximum outer diameter of the borosilicate glass material 12 is smaller than the maximum outer diameter of the second glass material 142. The borosilicate glass material 12 terminates one end of the quartz glass tube 11 via the intermediate glass material 14, preventing the inert gas inside the quartz glass tube 11 from leaking out.

[0027] The borosilicate glass material 13 includes a glass tube 131 and a glass bead 132. Both the glass tube 131 and the glass bead 132 are glass materials made of borosilicate glass. For example, the composition ratio of the glass tube 131 and the glass bead 132 is the same. The glass tube 131 is an annular member into which the glass bead 132 can be inserted. The glass tube 131 and the glass bead 132 seal the cathode 30 by melting each other. The borosilicate glass material 13 terminates the other end of the quartz glass tube 11, preventing the inert gas inside the quartz glass tube 11 from leaking out. Although the glass tube 131 and the glass bead 132 are depicted separately in Figure 1, they are welded together and integrated.

[0028] The outer diameter of the borosilicate glass material 12 is, for example, 1.0 mm or more and 4.9 mm or less, and is 2.65 mm as an example. The inner diameter of the borosilicate glass material 12 is the same as the outer diameter of the tungsten rod 21. The outer diameter of the borosilicate glass material 13 is, for example, 1.5 mm or more and 6.0 mm or less, and is 3.75 mm as an example. The inner diameter of the borosilicate glass material 13 is, for example, 1.0 mm or more and 4.9 mm or less, and is 2.65 mm as an example. The axial length of the borosilicate glass material 13 is, for example, 1.5 mm or more and 8.0 mm or less. The outer diameter of the borosilicate glass material 13 and the inner diameter of the glass tube 131 may be the same as the outer diameter and inner diameter of the quartz glass tube 11, but their shapes and sizes are not particularly limited.

[0029] The intermediate glass material 14 is an example of the first intermediate glass material, and is placed between the quartz glass tube 11 and the borosilicate glass material 12, joining the quartz glass tube 11 and the borosilicate glass material 12. Specifically, the intermediate glass material 14 joins one end of the quartz glass tube 11 in the axial direction to the borosilicate glass material 12.

[0030] The intermediate glass material 15 is an example of a second intermediate glass material, and is placed between the quartz glass tube 11 and the borosilicate glass material 13, joining the quartz glass tube 11 and the borosilicate glass material 13. Specifically, the intermediate glass material 15 joins the other end of the quartz glass tube 11 in the axial direction to the glass tube 131 of the borosilicate glass material 13.

[0031] Intermediate glass materials 14 and 15 are each two-tiered glass materials, also known as stepped seals. Specifically, intermediate glass material 14 includes a first glass material 141 joined to the quartz glass tube 11 and a second glass material 142 joined to the borosilicate glass material 12. The first glass material 141 and the second glass material 142 are joined to each other. Similarly, intermediate glass material 15 includes a first glass material 151 joined to the quartz glass tube 11 and a second glass material 152 joined to the borosilicate glass material 13. The first glass material 151 and the second glass material 152 are joined to each other. At least one of the intermediate glass materials 14 and 15 may be a single-tiered glass material. The number of tiers in each of the intermediate glass materials 14 and 15 may be the same or different.

[0032] The axial thickness of each of the intermediate glass materials 14 and 15 is, for example, 1 mm or more and 4 mm or less. The axial thickness of each of the intermediate glass materials 14 and 15 may be 1.5 mm or more and 2 mm or less. Note that the axial direction is the same as the axial direction of the quartz glass tube 11, i.e., the longitudinal direction.

[0033] The axial thickness of each of the first glass materials 141 and 151 joined to the quartz glass tube 11 is, for example, greater than 0 mm and 1.5 mm or less. The axial thickness of each of the first glass materials 141 and 151 may be 0.5 mm or more, or 1.0 mm or less.

[0034] The axial thickness of the second glass material 142 joined to the borosilicate glass material 12, and the second glass material 152 joined to the borosilicate glass material 13, is, for example, 0.5 mm or more and 3.0 mm or less. The axial thickness of the second glass materials 142 and 152 may be 0.8 mm or more and 2.0 mm or less. In this embodiment, the axial thickness of the second glass material 142 is greater than the axial thickness of the second glass material 152. Also, for example, the axial thickness of the second glass material 142 is greater than the axial thickness of the first glass material 141, but is not limited to this. The axial thickness of the second glass material 152 is greater than the axial thickness of the first glass material 151, but is not limited to this.

[0035] The first glass materials 141 and 151, and the second glass material 152, each have a flattened tubular (ring) shape. Flattening means that the axial thickness (length) is smaller than the outer diameter. The outer diameter of each of the first glass materials 141 and 151, and the second glass material 152, is 3 mm or more and 6.5 mm or less, with 4.0 mm as an example. The inner diameter of each of the first glass materials 141 and 151, and the second glass material 152, is 1.0 mm or more and 4.0 mm or less, with 2.35 mm as an example. The shape of the second glass material 142 is a bottomed cylindrical shape. The tungsten rod 21 of the anode 20 penetrates the bottom surface of the second glass material 142. The bottom surface of the second glass material 142 may be a flat surface or a dome-shaped curved surface. The maximum outer diameter of the second glass material 142 is between 3 mm and 6.5 mm, with 4.0 mm being an example. The maximum inner diameter of the second glass material 142 is between 1.0 mm and 4.0 mm, with 2.35 mm being an example.

[0036] As shown in Figure 3, the thickness T of the intermediate glass material 15 ２ The wall thickness T of the quartz glass tube 11 １ The following applies. For example, thick T ２ Thick T １ It is between 50% and 80%. Note that the intermediate glass material 15 is formed by welding, so its thickness may not be uniform. Thickness T of the intermediate glass material 15 ２ This can be considered as the thickness of the thinnest part of the intermediate glass material 15, i.e., the minimum thickness. Alternatively, the thickness T２ It may be regarded as the wall thickness at the center position of the intermediate glass material 15 in the axial direction, for example.

[0037] Although not shown in FIG. 3, the wall thickness of the intermediate glass material 14 is the wall thickness T of the quartz glass tube 11. １ is as follows. For example, the wall thickness of the intermediate glass material 14 is 50% or more and 80% or less of the wall thickness T. １ Similar to the intermediate glass material 15, the wall thickness of the intermediate glass material 14 may not be uniform. The wall thickness of the intermediate glass material 14 can be regarded as the wall thickness of the thinnest part of the intermediate glass material 14, that is, the minimum value of the wall thickness. Alternatively, the wall thickness of the intermediate glass material 14 may be regarded as, for example, the wall thickness at the center position of the intermediate glass material 14 in the axial direction.

[0038] The outer diameters and inner diameters of the first glass materials 141 and 151 and the second glass material 152 may be the same as each other, but their shapes, sizes, etc. are not particularly limited. In FIGS. 1 and 3, an example is shown where the outer diameters of the quartz glass tube 11, the first glass materials 141 and 151, and the second glass material 152 are equal to each other, but it is not limited to this. For example, at least one of the outer diameters of the first glass materials 141 and 151 and the second glass material 152 may be smaller than the outer diameter of the quartz glass tube 11.

[0039] In this embodiment, the number of stages of each of the intermediate glass materials 14 and 15 is two. Therefore, the axial length of the outer container 10 and the axial length (total length) of each of the flash discharge tubes 1 can be shortened. Thereby, a small-sized flash discharge tube 1 can be realized. The axial length of the flash discharge tube 1 is, for example, 30 mm or more and 85 mm or less, but may also be 35 mm or more and 65 mm or less.

[0040] The intermediate glass materials 14 and 15 each have a different composition from the borosilicate glass materials 12 and 13. Specifically, the intermediate glass materials 14 and 15 each contain SiO ２ (silicon dioxide) and B ２ O ３ (boron oxide). The content rate of SiO ２ in the intermediate glass material 14 is 75% or more and 90% or less. The B ２ O３ The content is between 8% and 15%. The same applies to the intermediate glass material 15. The content can be expressed in mass percent.

[0041] In this embodiment, each of the first glass material 141 and 151, and the second glass material 142 and 152, is SiO ２ and B ２ O ３ It contains SiO in each of the first glass material 141 and 151, and the second glass material 142 and 152. ２ The content of is 75% or more and 90% or less. B in each of the first glass materials 141 and 151 and the second glass materials 142 and 152 ２ O ３ The content is between 8% and 15%.

[0042] The SiO2 content in the first glass material 141 is higher than the SiO2 content in the second glass material 142. The B2O3 content in the first glass material 141 is lower than the B2O3 content in the second glass material 142. Also, the SiO in the first glass material 151 ２ The content of is SiO in the second glass material 152. ２ The content is higher than that of B in the first glass material 151. ２ O ３ The content of is B in the second glass material 152. ２ O ３ Its content is lower than that of [another entity].

[0043] SiO ２ and B ２ O ３ By adjusting the content of the material, the coefficient of thermal expansion increases in the order of quartz glass tube 11, first glass material 151, second glass material 152, and borosilicate glass material 13. The first glass material 151 and second glass material 152 can suppress abrupt changes in the coefficient of thermal expansion between the quartz glass tube 11 and the borosilicate glass material 13, thereby increasing the bonding strength between the glass materials. Furthermore, the coefficient of thermal expansion increases in the order of quartz glass tube 11, first glass material 141, second glass material 142, and borosilicate glass material 12. The first glass material 141 and second glass material 142 can suppress abrupt changes in the coefficient of thermal expansion between the quartz glass tube 11 and the borosilicate glass material 12, thereby increasing the bonding strength between the glass materials.

[0044] The thermal expansion coefficient of the quartz glass tube 11 is 5 × 10⁻⁶. －７ / ℃ or higher, 7 x 10 －７ It is below / °C. Furthermore, the thermal expansion coefficients of the borosilicate glass materials 12 and 13 are 37 × 10⁻⁶. －７ / ℃ or higher, 42 x 10 －７ It is below / ℃.

[0045] [Anode and Cathode] Next, the specific configurations of the anode 20 and cathode 30 will be explained using Figures 4 and 5.

[0046] As shown in Figure 4, the anode 20 includes a tungsten rod 21, a lead portion 22, and a joint portion 23. As shown in Figure 5, the cathode 30 includes a tungsten rod 31, a lead portion 32, a joint portion 33, and a sintered pellet 34. The anode 20 has the same configuration as the cathode 30, but without the sintered pellet 34. That is, the tungsten rod 21, lead portion 22, and joint portion 23 of the anode 20 correspond to the tungsten rod 31, lead portion 32, and joint portion 33 of the cathode 30, respectively. Note that the components other than the sintered pellet 34 do not need to be exactly the same; for example, the length of the tungsten rod 21 may differ from the length of the tungsten rod 31.

[0047] The tungsten rod 31 is located inside the enclosure 10. The lead portion 32 is located outside the enclosure 10 and is joined to the tungsten rod 31. The joint portion 33 is the part formed by joining the tungsten rod 31 and the lead portion 32. The joining can be done by means such as welding. Note that a portion of the tungsten rod 31 may be located outside the enclosure 10, and a portion of the lead portion 32 may be located inside the enclosure 10.

[0048] The tungsten rod 31 is a cylindrical conductive member mainly composed of tungsten. The tungsten rod 31 is the lead wire or electrode pin of the discharge electrode. The cathode 30 is fixed to the enclosure 10 by sealing the tungsten rod 31 to the borosilicate glass material 13. Since tungsten is a high melting point material, the tungsten rod 31 can withstand the heat during sealing and discharge. Furthermore, the thermal expansion coefficient of the tungsten rod 31 is equivalent to (for example, the same order of magnitude) that of the borosilicate glass material 13. This makes it possible to suppress damage to the borosilicate glass material 13 due to heat during sealing and discharge.

[0049] The lead portion 32 is a conductive member that receives power to cause the flash discharge tube 1 to emit light. For example, the lead portion 32 mainly contains nickel. Specifically, the lead portion 32 is made of nickel. This allows lead wires for connecting to the drive circuit to be easily connected to the lead portion 32 by soldering or resistance welding.

[0050] The sintered pellet 34 is a sintered body containing an emitter material that promotes electron emission. The emitter material is thermally decomposed and activated at temperatures between 800°C and 1100°C. In other words, the melting point of the emitter material is between 800°C and 1100°C. The melting point of the emitter material may be 1080°C or lower, or 1050°C or lower. For example, an emitter material with a melting point of 1010°C can be used.

[0051] Because the emitter material has a low melting point, it can be activated by the heat generated during sealing of the borosilicate glass material 13 between the glass tube 131 and the glass bead 132. Furthermore, because the emitter material has a high boiling point, the heat generated during sealing can suppress evaporation of the emitter material. Therefore, the heat generated during sealing can sufficiently activate the emitter material. Consequently, the initial characteristic ignition voltage of the flash discharge tube 1 becomes lower, and its variation can be suppressed. In other words, stable light emission becomes possible at a low voltage.

[0052] The emitter material contains a cesium compound. Examples of cesium compounds include cesium sulfate and cesium niobate. The emitter material may also contain a barium compound. Examples of barium compounds include barium oxide, barium hydroxide, and barium sulfate. The emitter material may consist of a cesium compound and a barium compound. Since the cesium compound has a low work function and high electron emission, the trigger voltage and ignition voltage can be lowered. Also, since the barium compound functions as a getter, it can take in oxygen generated inside the enclosure 10. Furthermore, since the barium compound has higher durability than the cesium compound, the lifespan of the flash discharge tube 1 can be extended.

[0053] The sintered pellet 34 is a sintered body having pores. Specifically, the sintered pellet 34 is a porous body. Multiple pores in the sintered pellet 34 are scattered on the surface and inside the sintered pellet 34. The porosity of the sintered pellet 34 is 25% to 33%. Cesium compounds and / or cesium obtained by the thermal decomposition of cesium compounds tend to remain in the pores. Therefore, the emitter material held in the pores functions as a source of emitter material consumed at the discharge surface, thus extending the lifespan of the flash discharge tube 1. Note that the higher the porosity, the greater the amount of emitter material impregnated, resulting in more stable light emission. On the other hand, the surface of the sintered pellet 34 becomes rougher, making it more prone to melting and scattering due to discharge. By setting the porosity to 25% to 33%, a balance can be struck between stabilizing light emission and suppressing melting and scattering.

[0054] The sintered pellets 34 contain a getter material. The getter material has an oxidation initiation temperature of 200°C or higher, and its oxidation rate above 600°C is faster than the average oxidation rate in the range of 200°C to 600°C. Simply put, oxidation of the getter material begins at temperatures above 200°C, and becomes active (intense) at temperatures above 600°C. This allows the sintered pellets 34 to absorb oxygen generated inside the enclosure 10. By reducing the oxygen inside the enclosure 10, the lifespan of the flash discharge tube 1 can be extended.

[0055] For example, the getter material may be tantalum or niobium. The sintered pellet 34 is a sintered body made of tantalum or niobium. The sintered pellet 34 may also be a sintered body made of a mixture of tantalum and niobium. Since tantalum or niobium has a high oxygen absorption capacity, it can efficiently take in oxygen generated inside the enclosure 10. Therefore, the lifespan of the flash discharge tube 1 can be extended.

[0056] The sintered pellet 34 has a cylindrical shape. The inner circumferential surface of the sintered pellet 34 contacts and covers the outer surface of the tungsten rod 31 around its axis. As shown in Figure 3, at the position where the tip of the sintered pellet 34 is positioned in the axial direction of the quartz glass tube 11 (tip position), the outer diameter R of the sintered pellet 34 is... ２ The inner diameter R of the outer enclosure 10 １ The following applies. In this embodiment, since the tip of the sintered pellet 34 is located inside the quartz glass tube 11, the inner diameter R of the outer container 10 １ The inner diameter R of the quartz glass tube 11 １ This corresponds to, for example, the outer diameter R. ２ The inner diameter R １ It is between 80% and 90%.

[0057] Furthermore, the inventors manufactured multiple samples of the flash discharge tube 1 and conducted luminescence durability tests on each. In the multiple samples, the outer diameter R of the sintered pellet 34 was ２ The outer diameter R of each sample was varied. ２ and inner diameter R １ or R ３ The ratio and the results of the luminescence durability test are as follows. Note that the inner diameter R ３ This is the inner diameter of the enclosure 10 at the tip position when the tip position of the sintered pellet 34 overlaps with the intermediate glass material 15, i.e., the inner diameter of the intermediate glass material 15. Further details will be explained later using Figures 10 to 13.

[0058]

[0059] Luminous durability refers to the ratio of the decrease in light intensity after the luminous durability test compared to the initial light intensity. In the luminous durability test, the main capacitor capacity was set to 1700 μF, and the voltage applied between the anode 20 and cathode 30 was set to 320 V. This translates to an input power of 87 Ws for the flash discharge tube 1. The test was performed 300,000 times with luminescence at 4.5-second intervals, with a pause of about 10 minutes in between. Also, the outer diameter R ２ and inner diameter R １ or R ３ Other than the ratio, all other conditions are common to each sample.

[0060] As shown in Table 1, the outer diameter R ２ The inner diameter R １ or R ３ If the outer diameter R is too large or too small, the decrease in light output is significant, and the required luminescence durability (specifically, a decrease of 20% or less from the initial light output) cannot be achieved. Specifically, the outer diameter R ２ The inner diameter R １ or R ３ Good luminescence durability was obtained within the range of 80% to 90%.

[0061] In this embodiment, as shown in Figure 1, the respective tips of the anode 20 and cathode 30 are located inside the quartz glass tube 11. The tip is defined as the part that is directed toward the center in the axial direction of the quartz glass tube 11. Specifically, the tip of the anode 20 is the part of the tungsten rod 21 opposite to the joint 23. The tip of the cathode 30 is the part of the tungsten rod 31 opposite to the joint 33.

[0062] In the cathode 30, the sintered pellets 34 overlap the intermediate glass material 15 when viewed from a direction perpendicular to the axial direction of the quartz glass tube 11 (side view). In this embodiment, the sintered pellets 34 overlap the quartz glass tube 11, the intermediate glass material 15, and the borosilicate glass material 13 in a side view. In other words, the sintered pellets 34 are arranged across the quartz glass tube 11 and the borosilicate glass material 13.

[0063] The tips of the anode 20 and cathode 30 are parts that tend to become hot during discharge. By positioning the tips of the anode 20 and cathode 30 inside the quartz glass tube 11, which has better heat resistance than the borosilicate glass materials 12 and 13 and the intermediate glass materials 14 and 15, the influence of the heat generated by the anode 20 and cathode 30 on the enclosure 10 can be suppressed.

[0064] Specifically, near the joints between each of the intermediate glass materials 14 and 15 and each of the quartz glass tube 11 and borosilicate glass material 12, strain remains because the joining of glass materials has different softening points and thermal expansion coefficients. If the heat generated at the anode 20 and cathode 30 when the flash discharge tube 1 is in use is transmitted to the areas where strain remains, there is a risk of cracks occurring due to thermal shock.

[0065] In contrast, the hottest tips of the anode 20 and cathode 30 are located inside the quartz glass tube 11. That is, by separating the tips of the anode 20 and cathode 30 from the vicinity of the intermediate glass materials 14 and 15, the thermal shock applied to the vicinity of the intermediate glass materials 14 and 15 can be mitigated, and the occurrence of cracks can be suppressed.

[0066] Furthermore, in the cathode 30, the amount of tungsten rod 31 protruding from the sintered pellet 34 is increased. Specifically, the distance D between the tip of the tungsten rod 31 and the sintered pellet 34 is 1.5 mm or more and 2.0 mm or less, with 1.8 mm as an example. This makes it easier for the high-melting-point tungsten rod 31 to receive discharge, and reduces the amount of discharge (ion collision) received by the sintered pellet 34. This improves the light emission durability of the cathode 30 and extends the lifespan of the flash discharge tube 1.

[0067] [Trigger Winding] Next, the trigger winding 40 will be explained using Figure 2.

[0068] The trigger winding 40 is a conductive member to which a trigger voltage is applied when the flash discharge tube 1 is made to emit light. The trigger winding 40 is a metal wire made of, for example, nickel or copper. In this embodiment, as can be seen by comparing Figure 1 and Figure 2, the trigger winding 40 is wound around the outer surface of the intermediate glass material 15. For example, the trigger winding 40 covers the entire outer surface of the intermediate glass material 15 from the end of the quartz glass tube 11 to the borosilicate glass material 13. When viewed from a direction perpendicular to the axial direction of the quartz glass tube 11, the trigger winding 40 covers the sintered pellet 34.

[0069] Between the trigger winding 40 and the sintered pellet 34 lies a thin section of the enclosure 10, specifically the intermediate glass material 15. Therefore, the trigger voltage applied to the trigger winding 40 easily excites the emitter material contained in the sintered pellet 34, causing the emitter material to release electrons more readily. This allows for light emission at low trigger voltages and low ignition voltages. Furthermore, variations in the ignition voltage can be suppressed.

[0070] Note that the trigger voltage is an example of a first voltage of 1kV or higher. For example, the trigger voltage is 5kV. Also, although the trigger voltage is less than 7.5kV, it may be 7kV or less, 6kV or less, or 5.5kV or less.

[0071] Furthermore, the ignition voltage is an example of a second or third voltage applied between the anode 20 and cathode 30 when the flash discharge tube 1 emits light. For example, the ignition voltage is 250V or more and 660V or less, but it may be 500V or less, 400V or less, or 350V or less. Also, for example, the ignition voltage may be 200V or more and 330V or less, and stable light emission is possible.

[0072] The flash discharge tube 1 does not necessarily have to be equipped with a trigger winding 40. The flash discharge tube 1 is equipped with a translucent conductive film (Nesa film) covering the outer surface of the quartz glass tube 11, and a trigger voltage may be applied to the translucent conductive film. If a Nesa film is not formed on the flash discharge tube 1, a reflector umbrella can be used as a trigger electrode instead of the Nesa film. An enclosure 10 is placed along the bottom surface of the reflector umbrella, and a trigger voltage is applied between the respective tips of the anode 20 and cathode 30 inside the quartz glass tube 11. A trigger voltage is also applied to the trigger wire of the flash discharge tube 1.

[0073] [Manufacturing Method] Next, the manufacturing method of the flash discharge tube 1 according to this embodiment will be described using Figures 6 to 9. Figures 6 to 9 are schematic diagrams showing each step of the manufacturing method of the flash discharge tube 1 according to this embodiment.

[0074] First, an anode 20 to which a glass bead made of borosilicate glass material 12 is fixed, and a cathode 30 to which a glass bead 132 is fixed are prepared. Specifically, the anode 20 is formed by joining a tungsten rod 21 and a lead portion 22 by welding or the like. Similarly, the cathode 30, which does not have a sintered pellet 34, is formed by joining a tungsten rod 31 and a lead portion 32 by welding or the like. Next, the glass bead (borosilicate glass material 12) and the glass bead 132 are airtightly sealed to the tungsten rods 21 and 31, respectively. The tungsten rod 21 and the borosilicate glass material 12, and the tungsten rod 31 and the glass bead 132 are sealed without any gaps.

[0075] Next, a sintered pellet 34 is formed. Specifically, a sintered pellet 34 is formed by impregnating a cylindrical sintered body with an emitter material. For example, an aqueous solution containing a predetermined concentration of a cesium compound is impregnated into the sintered body and dried. The predetermined concentration is, for example, 10% to 45%. The aqueous solution may contain not only a cesium compound but also a barium compound. Then, the dried sintered pellet 34 is fixed to the tungsten rod 31 by crimping or the like.

[0076] Next, an intermediate glass material 14 is welded to one end of the quartz glass tube 11, and an intermediate glass material 15 is welded to the other end. Specifically, as shown in Figure 6, the intermediate glass materials 14 and 15, and the glass tube 131 are formed at both ends of the quartz glass tube 11. For example, the quartz glass tube 11 is held rotatably around its axis using a glass lathe, and while heating the cathode 30 side end of the quartz glass tube 11 with a burner, the first glass material 151, the second glass material 152, and the glass tube 131 are formed in that order. Similarly, while rotating the quartz glass tube 11 and heating the anode 20 side end with a burner, the first glass material 141 and the second glass material 142 are formed in that order. For example, while rotating the quartz glass tube 11 around its axis, the tip of a glass rod having the same composition as the first glass material 151 is brought close to the heated end of the quartz glass tube 11 and the glass rod is melted. The molten glass covers the end of the quartz glass tube 11 along the direction of rotation, thereby forming the first glass material 151. The second glass material 152, glass tube 131, first glass material 141, and second glass material 142 can be formed by the same method.

[0077] In this embodiment, an intermediate glass material 14 is welded to one end of the quartz glass tube 11 to seal it, and then a through-hole is formed in the intermediate glass material 14. The through-hole is for inserting the tungsten rod 21 of the anode 20. Specifically, a first glass material 141 is formed in an annular shape at one end of the quartz glass tube 11, and then a second glass material 142 is formed to seal the opening of the first glass material 141. After that, the second glass material 142 is inflated into a dome shape to form a bottomed cylindrical shape, and a through-hole for inserting the tungsten rod 21 is formed by blowing open a part of the bottom surface.

[0078] Furthermore, the wall thickness of at least one of the first glass material 151 and the second glass material 152 may be made thinner than the wall thickness of the quartz glass tube 11. Also, the wall thickness of at least one of the first glass material 141 and the second glass material 142 may be made thinner than the wall thickness of the quartz glass tube 11. By making the wall thickness thinner, the residual strain in each of the intermediate glass material 15 (first glass material 151 and second glass material 152) and intermediate glass material 14 (first glass material 141 and second glass material 142) can be reduced. This makes it possible to improve the light emission durability of the flash discharge tube 1.

[0079] Next, as shown in Figure 7, with the tungsten rod 21 of the anode 20 with a glass bead (borosilicate glass material 12) attached inserted into a through hole provided in the second glass material 142, the borosilicate glass material 12 and the intermediate glass material 14 are air-sealed together. Specifically, the tungsten rod 21 is inserted into a through hole provided in the second glass material 142, and with the borosilicate glass material 12 in contact with the area around the opening of the through hole in the second glass material 142, the borosilicate glass material 12 and the second glass material 142 are air-sealed together. Note that since the anode 20 does not have a sintered body containing an emitter material, it is not necessary to consider the relationship between the decomposition temperature of the emitter material and the heating temperature during sealing. By sealing the glass bead, which is pre-welded to the tungsten rod 21, with the second glass material 142, the axial length can be shortened.

[0080] The sealing of the borosilicate glass material 12 fixed to the anode 20 and the intermediate glass material 14 may be performed continuously from the fusion joining of the quartz glass tube 11 and the intermediate glass material 14. "Continuously" means that a sufficient cooling period is not allowed, and the borosilicate glass material 12 and the intermediate glass material 14 are sealed before the temperature of the intermediate glass material 14 drops and hardens. By performing the sealing before the temperature of the intermediate glass material 14 drops, it is possible to avoid the thermal shock generated during sealing being added to the strain generated inside the intermediate glass material 14 due to the temperature drop. After sealing, the intermediate glass material 14 is heated to suppress strain while being gradually cooled. This suppresses the generation of strain near the intermediate glass material 14 and prevents cracks from forming due to thermal shock during manufacturing and use. The first glass material 151, the second glass material 152, and the glass tube 131 on the cathode 30 side may be formed after sealing the borosilicate glass material 12 and the intermediate glass material 14.

[0081] Next, as shown in Figure 8, an inert gas is introduced into the enclosure 10 (quartz glass tube 11) using an exhaust sealing device 90. The exhaust sealing device 90 houses the enclosure 10, to which the anode 20 is fixed. The space that houses the enclosure 10 (housing space) is provided with a gas exhaust path and an air supply path, and valves 91 and 92 are provided in each path. With the enclosure 10 housed, valve 91 is opened to exhaust the gas in the housing space and create a vacuum in the housing space. Then, by closing valve 91 and opening valve 92, the inert gas is introduced into the housing space. As a result, the inert gas is introduced into the enclosure 10 from the cathode 30 side end.

[0082] Next, as shown in Figure 9, the cathode 30 with the glass bead 132 is sealed to the glass tube 131 of the enclosure 10 under an inert gas atmosphere. Specifically, the tungsten rod 31 of the cathode 30 and the glass bead 132 are inserted into the glass tube 131 and heated to melt and join the glass bead 132 and the glass tube 131. The heating temperature for sealing is between 800°C and 1100°C. The heating for sealing the glass bead 132 and the glass tube 131 is used to activate the emitter material of the sintered pellet 34. Since the melting point of the emitter material is equal to or lower than the heating temperature, the emitter material can be sufficiently activated.

[0083] After bonding, cooling is started with the chamber filled with inert gas. After exhausting the inert gas, the chamber is slowly cooled in a vacuum-insulated state (i.e., cooled while heating) to suppress the strain that occurs near the intermediate glass material 15. Note that in Figures 8 and 9, the fixtures that support the enclosure 10 and the cathode 30 (for example, fixtures made of carbon), and the heating device are not shown.

[0084] The flash discharge tube 1 can be manufactured through the above process. Note that the above-described method for manufacturing the flash discharge tube 1 is merely an example and can be modified as appropriate.

[0085] In the flash discharge tube 1, at the joints between the intermediate glass material 14 and the quartz glass tube 11 and the borosilicate glass material 12, a bonding force is generated between the dissimilar glass materials around the joint interface. Also, when the molten glass cools (when the viscosity of the glass increases), strain remains inside the glass. To improve the sealing performance of the outer casing 10 and suppress breakage, the balance between this bonding force and strain is important. Specifically, the bonding force must be greater than the strain. Furthermore, after manufacturing, it is important that the temperature near the intermediate glass material 14 does not reach the thermal shock temperature at the operating temperature of the flash discharge tube 1.

[0086] In the manufacturing method of the flash discharge tube 1 according to this embodiment, the temperature of the intermediate glass materials 14 and 15 is controlled while sealing the anode 20 and cathode 30, respectively. This makes it possible to suppress the strain that occurs near the intermediate glass materials 14 and 15. When the flash discharge tube 1 is in use, the anode 20 tends to become hotter than the cathode 30. Therefore, by performing the formation of the intermediate glass material 14 near the anode 20 and the sealing of the anode 20 continuously without a cooling period, the strain that occurs near the intermediate glass material 14 can be further suppressed. Because the strain can be suppressed, the quartz glass tube 11 and the borosilicate glass materials 12 and 13 can be joined even if the number of layers of the intermediate glass materials 14 and 15 is reduced.

[0087] Furthermore, to increase the bonding strength, the dissimilar glasses may be heated and welded together at a temperature above the annealing point of their respective temperature-viscosity characteristics. In this case, the bonding area can be increased and the bonding strength increased by softening the bonding surface and shaping the sealing area by expanding and contracting it with compressed air (making the glass thickness uniform).

[0088] Furthermore, joining ring-shaped sintered glass made from different types of glass is difficult because the degree of shrinkage when heated differs for each type of glass. Glass has the property of shrinking and becoming round when heated to a temperature above its softening point. Therefore, even if ring-shaped pieces of different types of glass are heated and fused together in a gradient furnace with a temperature gradient, the amount of volume shrinkage will differ because each type of glass has a different thermal expansion coefficient. As a result, simply applying heat will not allow them to join, and they will be prone to coming apart. Specifically, because the glass pieces are in point contact with each other, even if they are joined locally, the stress from their strains will pull against each other, potentially causing cracks or separation starting from the joint.

[0089] In contrast, in the manufacturing method of the flash discharge tube 1 according to this embodiment, the glass tubes 131 of the intermediate glass materials 14 and 15, and the borosilicate glass material 12 and borosilicate glass material 13 are formed by sequentially melting glass at the end of the quartz glass tube 11. This ensures a bonding area between different types of glass, thereby increasing the bonding strength. As a result, the light emission durability of the flash discharge tube 1 can be improved.

[0090] [Modifications] Next, several modifications of the flash discharge tube 1 according to the embodiment will be described using Figures 10 to 13. Figures 10 to 13 are enlarged side views showing the vicinity of the cathode 30 of flash discharge tubes 1A, 1B, 1C, and 1D according to modification 1 to 4, respectively. In the following, the differences from the flash discharge tube 1 according to the embodiment will be explained in detail, and the explanation of common points will be omitted or simplified.

[0091] In the flash discharge tube 1A shown in Figure 10 and the flash discharge tube 1B shown in Figure 11, the position of the sintered pellet 34 is different compared to the flash discharge tube 1. Specifically, in the flash discharge tube 1A shown in Figure 10 and the flash discharge tube 1B shown in Figure 11, the end of the sintered pellet 34 (the end on the tip side of the tungsten rod 31) is set back towards the lead portion 32 than the end of the intermediate glass material 15 (the end on the tip side of the tungsten rod 31). In other words, in a side view, the sintered pellet 34 does not overlap with the quartz glass tube 11 and a part of the intermediate glass material 15, but overlaps with another part of the intermediate glass material 15 and the borosilicate glass material 13. Specifically, in the flash discharge tube 1A shown in Figure 10, the sintered pellet 34 overlaps with the first glass material 151 and the second glass material 152 in a side view. In the flash discharge tube 1B shown in Figure 11, the sintered pellet 34, in a side view, does not overlap the first glass material 151 but overlaps the second glass material 152.

[0092] In the flash discharge tube 1A shown in Figure 10, in a side view, the tip of the sintered pellet 34 overlaps with the first glass material 151 of the intermediate glass material 15. Therefore, at the tip of the sintered pellet 34, the inner diameter of the enclosure 10 is equal to the inner diameter R of the first glass material 151. ３ This means that in the flash discharge tube 1A, at the tip position of the sintered pellet 34, the outer diameter R of the sintered pellet 34 ２ This is the inner diameter R at the end of the first glass material 151. ３ Smaller than, for example, inner diameter R ３ It is between 80% and 90%. The tip of the sintered pellet 34 may be located at the boundary between the quartz glass tube 11 and the first glass material 151 in a side view.

[0093] In the flash discharge tube 1B shown in Figure 11, in a side view, the tip of the sintered pellet 34 overlaps with the second glass material 152 of the intermediate glass material 15. Therefore, at the tip of the sintered pellet 34, the inner diameter of the enclosure 10 is equal to the inner diameter R of the second glass material 152. ３ This means that, in the flash discharge tube 1B, at the tip position of the sintered pellet 34, the outer diameter R of the sintered pellet 34 ２ The inner diameter R of the second glass material 152 ３ Smaller than, for example, inner diameter R ３It is between 80% and 90%. The end of the sintered pellet 34 (the end on the tip side of the tungsten rod 31) may be located at the boundary between the first glass material 151 and the second glass material 152 in a side view.

[0094] Thus, the sintered pellet 34 only needs to overlap the intermediate glass material 15 in a side view, and does not need to overlap the quartz glass tube 11. Also, the sintered pellet 34 does not need to overlap the borosilicate glass material 13 in a side view. With such flash discharge tubes 1A and 1B, the same effects as the flash discharge tube 1 can be achieved, such as improved light emission durability and lower and stabilized ignition voltage.

[0095] In the flash discharge tube 1C shown in Figure 12 and the flash discharge tube 1D shown in Figure 13, the inner diameter R of the quartz glass tube 11 is different compared to flash discharge tubes 1, 1A, and 1B. １ and the outer diameter R of the sintered pellet 34 ２ The relative sizes are different. Specifically, in flash discharge tubes 1C and 1D, the inner diameter R of the quartz glass tube 11 １ The outer diameter R of the sintered pellet 34 ２ It is smaller than [the other one]. In the flash discharge tube 1C, the arrangement position of the sintered pellets 34 is the same as in the flash discharge tube 1A. The ends of the sintered pellets 34 are separated. In the flash discharge tube 1D, the arrangement position of the sintered pellets 34 is the same as in the flash discharge tube 1B.

[0096] Thus, the inner diameter R of the quartz glass tube 11 １ By reducing the size of the tube, the tube current can be reduced. Reducing the tube current suppresses current noise in the drive circuit of the control device for the flash discharge tubes 1C and 1D, thereby suppressing malfunctions in the peripheral and adjacent circuits of the control device. It also expands the range of choices for current-resistant design considerations when selecting components for the drive circuit. Furthermore, reducing the tube current reduces the burden on the cathode 30, which is expected to extend the lifespan of the flash discharge tubes 1C and 1D. In addition, since the sintered pellet 34 becomes relatively larger, surface melting due to discharge is suppressed, thus improving the durability of the light emission.

[0097] [Effects, etc.] The flash discharge tube according to the first aspect of the present invention is, for example, the flash discharge tube 1, 1A, 1B, 1C, or 1D described above, and comprises a translucent outer casing 10 in which an inert gas is sealed inside, an anode 20 disposed at one end of the outer casing 10, and a cathode 30 disposed at the other end of the outer casing 10. The enclosure 10 includes a quartz glass tube 11, a borosilicate glass material 12 positioned at one end of the quartz glass tube 11 to seal the anode 20, a borosilicate glass material 13 positioned at the other end of the quartz glass tube 11 to seal the cathode 30, an intermediate glass material 14 positioned between the quartz glass tube 11 and the borosilicate glass material 12 to join the quartz glass tube 11 and the borosilicate glass material 12, and an intermediate glass material 15 positioned between the quartz glass tube 11 and the borosilicate glass material 13 to join the quartz glass tube 11 and the borosilicate glass material 13. The intermediate glass material 14 and the intermediate glass material 15 are each one- or two-stage glass materials. The tip of the cathode 30 is located inside the quartz glass tube 11. The cathode 30 has a sintered pellet 34. When viewed from a direction perpendicular to the axial direction of the quartz glass tube 11, the sintered pellet 34 overlaps the intermediate glass material 15.

[0098] This allows the tip of the cathode 30, which becomes hot during use, to be kept away from the vicinity of the intermediate glass material 15, thereby suppressing thermal shock to the vicinity of the intermediate glass material 15. As a result, crack formation near the intermediate glass material 15 is suppressed, making it possible to realize flash discharge tubes 1, 1A, 1B, 1C, or 1D that are less prone to breakage and have high luminescence durability.

[0099] Furthermore, since the number of stages in each of the intermediate glass materials 14 and 15 is two or less, the overall length of the flash discharge tube 1, 1A, 1B, 1C, or 1D can be shortened. Thus, a compact flash discharge tube 1, 1A, 1B, 1C, or 1D can be realized. Also, since the number of stages in each of the intermediate glass materials 14 and 15 is two or less, the lengths of the anode 20 and cathode 30 can also be shortened. Specifically, the tungsten rods 21 and 31 can be shortened, thereby reducing the weight of the flash discharge tube 1, 1A, 1B, 1C, or 1D. In addition, since tungsten is generally expensive, shortening the tungsten rods 21 and 31 can reduce the cost of the flash discharge tube 1, 1A, 1B, 1C, or 1D.

[0100] A flash discharge tube according to a second aspect of the present invention is a flash discharge tube according to the first aspect, wherein the sintered pellet 34 includes an emitter material that is thermally decomposed and activated at a temperature of 800°C to 1100°C.

[0101] This allows the emitter material to be efficiently thermally decomposed and activated by the heat generated during the sealing of the cathode 30. Sufficient activation of the emitter material allows for a lower ignition voltage and suppresses variations in the ignition voltage.

[0102] A flash discharge tube according to a third aspect of the present invention is a flash discharge tube according to a second aspect, wherein the emitter material contains a cesium compound.

[0103] As a result, cesium compounds have a low work function and high electron emission, allowing for lower trigger voltages and ignition voltages.

[0104] A flash discharge tube according to a fourth aspect of the present invention is a flash discharge tube according to a third aspect, wherein the emitter material further comprises a barium compound.

[0105] As a result, the barium compound also functions as a getter, allowing it to take in oxygen generated inside the enclosure 10. Furthermore, since the barium compound has higher durability than the cesium compound, it is possible to extend the lifespan of the flash discharge tubes 1, 1A, 1B, 1C, or 1D.

[0106] A flash discharge tube according to a fifth aspect of the present invention is a flash discharge tube according to a third or fourth aspect, wherein the sintered pellet 34 has pores.

[0107] As a result, the emitter material is retained not only on the surface of the sintered pellet 34 but also within the pores. The emitter material retained within the pores functions as a source of emitter material consumed at the discharge surface, thus enabling a longer lifespan for the flash discharge tubes 1, 1A, 1B, 1C, or 1D.

[0108] A flash discharge tube according to the sixth aspect of the present invention is a flash discharge tube according to the fifth aspect, wherein the porosity of the sintered pellet 34 is 25% or more and 33% or less.

[0109] As the porosity increases, the amount of emitter material impregnated increases, resulting in more stable light emission. On the other hand, the surface of the sintered pellet 34 becomes rougher, making it more prone to melting and scattering due to electrical discharge. By setting the porosity between 25% and 33%, a balance can be struck between stabilizing light emission and suppressing melting and scattering.

[0110] A flash discharge tube according to the seventh aspect of the present invention is a flash discharge tube according to any one of the first to sixth aspects, wherein the sintered pellet 34 has an oxidation start temperature of 200°C or higher and includes a getter material whose oxidation rate is faster than the average oxidation rate in the range of 200°C to 600°C.

[0111] This allows the sintered pellets 34 to absorb the oxygen generated inside the enclosure 10. By reducing the oxygen inside the enclosure 10, the lifespan of the flash discharge tubes 1, 1A, 1B, 1C, or 1D can be extended.

[0112] The flash discharge tube according to the eighth aspect of the present invention is a flash discharge tube according to any one of the first to seventh aspects, wherein the sintered pellet 34 is a sintered body made of tantalum or niobium.

[0113] As a result, tantalum or niobium, which have high oxygen absorption capabilities, can efficiently take in oxygen generated inside the enclosure 10. Therefore, the lifespan of the flash discharge tubes 1, 1A, 1B, 1C, or 1D can be extended.

[0114] A flash discharge tube according to the ninth aspect of the present invention is a flash discharge tube according to any one of the first to eighth aspects, wherein the wall thickness of the intermediate glass material 15 is 50% or more and 80% or less of the wall thickness of the quartz glass tube 11.

[0115] As a result, the thickness of the intermediate glass material 15 located near the sintered pellet 34 is reduced, making it easier for the trigger voltage to be transmitted to the emitter material contained in the sintered pellet 34. Therefore, the excitation of the emitter material is performed efficiently, and the trigger voltage can be lowered. In addition, the ignition voltage can be lowered and variations in the ignition voltage can be suppressed.

[0116] A flash discharge tube according to the tenth aspect of the present invention is a flash discharge tube according to any one of the first to ninth aspects, wherein the outer diameter R of the sintered pellet 34 at the position where the tip of the sintered pellet 34 is located in the axial direction of the quartz glass tube 11 ２ This is the inner diameter R of the enclosure 10 at the position where the tip of the sintered pellet 34 is positioned. １ or R ３ It is between 80% and 90%.

[0117] This makes it possible to improve the light emission durability of the flash discharge tubes 1, 1A, 1B, 1C, or 1D.

[0118] A flash discharge tube according to the eleventh aspect of the present invention is a flash discharge tube according to any one of the first to tenth aspects, wherein the cathode 30 comprises a tungsten rod 31 disposed inside the enclosure 10 and a lead portion 32 disposed outside the enclosure 10 and joined to the tungsten rod 31. The lead portion 32 is made of nickel.

[0119] This allows lead wires for connecting to the drive circuit that drives the flash discharge tubes 1, 1A, 1B, 1C, or 1D to be easily connected to the lead portion 32 by soldering or resistance welding.

[0120] A flash discharge tube according to the twelfth aspect of the present invention is a flash discharge tube according to any one of the first to eleventh aspects, wherein the borosilicate glass material 12 and the borosilicate glass material 13 have different shapes.

[0121] This makes it possible to shape the borosilicate glass materials 12 and 13 into shapes suitable for sealing and holding the anode 20 and cathode 30, respectively.

[0122] A flash discharge tube according to a thirteenth aspect of the present invention is a flash discharge tube according to a twelfth aspect, wherein the maximum outer diameter of the borosilicate glass material 12 is smaller than the maximum outer diameter of the borosilicate glass material 13.

[0123] Since the anode 20 does not have a sintered body containing an emitter material, it is not necessary to consider the relationship between the decomposition temperature of the emitter material and the heating temperature during sealing. By pre-welding a glass bead (borosilicate glass material 12) with a small outer diameter to the anode 20 and then sealing the glass bead and the intermediate glass material 14 with air, the axial length can be shortened.

[0124] A flash discharge tube according to the 14th aspect of the present invention is a flash discharge tube according to any one of the 1st to 13th aspects, further comprising a trigger winding 40 wound around the outer surface of an intermediate glass material 15.

[0125] This allows the trigger voltage applied to the trigger winding 40 to be efficiently transmitted to the emitter material contained in the sintered pellet 34. As a result, the emitter material is efficiently excited, enabling stable illumination with a low ignition voltage even in light-emitting circuits with a trigger voltage of 7.5 kV or less. Furthermore, it is possible to lower the ignition voltage and suppress variations in the ignition voltage. Lowering the ignition voltage enables continuous illumination at short intervals with low light intensity.

[0126] A phototherapy apparatus according to the 15th aspect of the present invention is, for example, the phototherapy apparatus 200 shown in Figure 14, which comprises a flash discharge tube according to any one of the 1st to 14th aspects.

[0127] As a result, the light therapy device 200 is equipped with a flash discharge tube with high light emission durability, thereby improving its reliability and yield. The light therapy device 200 is used for purposes such as hair growth suppression, hair removal, skin beautification, and cosmetic purposes. The light therapy device 200 irradiates the skin of the human body with light emitted from flash discharge tubes 1, 1A, 1B, 1C, or 1D. By performing continuous emission of low-intensity light at short intervals, it is possible to achieve a total light output level that is the same as or higher than that of conventional devices. Therefore, with the light therapy device 200 according to this embodiment, effects such as hair growth suppression and skin beautification can be obtained.

[0128] A sixteenth aspect of the present invention relates to a method for manufacturing a flash discharge tube, which includes the steps of: sealing a glass bead made of borosilicate glass to the tungsten rod 21 of an anode 20 including a tungsten rod 21; welding an intermediate glass material 14 to one end of a quartz glass tube 11; and sealing the intermediate glass material 14 and the glass bead with air while the tungsten rod 21 is inserted into a through hole provided in the intermediate glass material 14.

[0129] This allows the glass bead to be pre-welded to the anode 20 and the glass bead to be airtightly sealed to the intermediate glass material 14, thereby shortening the axial length of the quartz glass tube 11. As a result, a small flash discharge tube can be manufactured.

[0130] A method for manufacturing a flash discharge tube according to the 17th aspect of the present invention is a method for manufacturing a flash discharge tube according to the 16th aspect, wherein in the step of welding the intermediate glass material 14, the intermediate glass material 14 is welded so as to close one end of the quartz glass tube 11, a through hole is formed in the intermediate glass material 14, and in the step of air-sealing the intermediate glass material 14 and the glass bead, a tungsten rod 21 is inserted into the through hole, and the intermediate glass material 14 and the glass bead are air-sealed together with the glass bead in contact with the area around the opening of the through hole in the intermediate glass material 14.

[0131] This makes it easy to perform hermetically sealing of the quartz glass tube 11 and fixing of the anode 20.

[0132] (Other) The flash discharge tube, phototherapy apparatus, and method for manufacturing the flash discharge tube according to the present invention have been described above based on the above embodiments, but the present invention is not limited to the above embodiments.

[0133] For example, the borosilicate glass material 12 that seals the anode 20 may have the same configuration as the borosilicate glass material 13 that seals the cathode 30.

[0134] Furthermore, for example, molybdenum rods may be used instead of tungsten rods 21 and 31 as lead wires for the anode 20 and cathode 30. In this case, aluminosilicate glass tubes can be used instead of borosilicate glass materials 12 and 13. This improves the adhesion with the molybdenum rods and enhances the sealing of the inert gas into the enclosure 10.

[0135] Furthermore, the present invention may be realized as a light-emitting device, light source device, or illumination device, etc., comprising flash discharge tubes 1, 1A, 1B, 1C, or 1D. The light-emitting device is, for example, a camera strobe device. The present invention may also be realized as a camera comprising flash discharge tubes 1, 1A, 1B, 1C, or 1D.

[0136] Furthermore, the present invention also includes forms obtained by applying various modifications to each embodiment that a person skilled in the art could conceive, as well as forms realized by arbitrarily combining the components and functions of each embodiment without departing from the spirit of the present invention.

[0137] 1, 1A, 1B, 1C, 1D Flash discharge tube 10 Enclosure 11 Quartz glass tube 12 Borosilicate glass material (first borosilicate glass material) 13 Borosilicate glass material (second borosilicate glass material) 14 Intermediate glass material (first intermediate glass material) 15 Intermediate glass material (second intermediate glass material) 20 Anode 21, 31 Tungsten rod 22, 32 Lead section 30 Cathode 34 Sintered pellet 40 Trigger winding 141, 151 First glass material 142, 152 Second glass material 200 Phototherapy device

Claims

1. A translucent enclosure with an inert gas sealed inside; an anode located at one end of the enclosure; and a cathode located at the other end of the enclosure, wherein the enclosure includes a quartz glass tube; a first borosilicate glass material located at one end of the quartz glass tube and sealing the anode; a second borosilicate glass material located at the other end of the quartz glass tube and sealing the cathode; a first intermediate glass material located between the quartz glass tube and the first borosilicate glass material and joining the quartz glass tube and the first borosilicate glass material; and a second intermediate glass material located between the quartz glass tube and the second borosilicate glass material and joining the quartz glass tube and the second borosilicate glass material, wherein the first intermediate glass material and the second intermediate glass material are each made of glass material consisting of one or two layers. A flash discharge tube wherein the tip of the cathode is located inside the quartz glass tube, the cathode has a sintered body, and the sintered body overlaps the second intermediate glass material when viewed from a direction perpendicular to the axial direction of the quartz glass tube.

2. The flash discharge tube according to claim 1, wherein the sintered body includes an emitter material that is thermally decomposed and activated at a temperature of 800°C to 1100°C.

3. The flash discharge tube according to claim 2, wherein the emitter material contains a cesium compound.

4. The flash discharge tube according to claim 3, wherein the emitter material further comprises a barium compound.

5. The sintered body has pores, as described in claim 3.

6. The porosity of the sintered body is 25% or more and 33% or less, as described in claim 5.

7. The flash discharge tube according to any one of claims 1 to 6, wherein the sintered body includes a getter material whose oxidation onset temperature is 200°C or higher, and whose oxidation rate is faster than the average oxidation rate in the range of 200°C to 600°C.

8. The flash discharge tube according to any one of claims 1 to 6, wherein the sintered body is a sintered body made of tantalum or niobium.

9. The flash discharge tube according to any one of claims 1 to 6, wherein the wall thickness of the second intermediate glass material is 50% or more and 80% or less of the wall thickness of the quartz glass tube.

10. The flash discharge tube according to any one of claims 1 to 6, wherein the outer diameter of the sintered body at the position where the tip of the sintered body is located in the axial direction of the quartz glass tube is 80% or more and 90% or less of the inner diameter of the enclosure at the position where the tip of the sintered body is located.

11. The flash discharge tube according to any one of claims 1 to 6, wherein the cathode comprises a tungsten rod disposed inside the enclosure and a lead portion disposed outside the enclosure and joined to the tungsten rod, the lead portion being made of nickel.

12. The flash discharge tube according to any one of claims 1 to 6, wherein the first borosilicate glass material and the second borosilicate glass material have different shapes.

13. The flash discharge tube according to claim 12, wherein the maximum value of the outer diameter of the first borosilicate glass material is smaller than the maximum value of the outer diameter of the second borosilicate glass material.

14. A flash discharge tube according to any one of claims 1 to 6, further comprising a trigger winding wound around the outer surface of the second intermediate glass material.

15. A phototherapy apparatus comprising a flash discharge tube according to any one of claims 1 to 6.

16. A method for manufacturing a flash discharge tube, comprising the steps of: air-sealing a glass bead made of borosilicate glass to a tungsten rod in an anode containing a tungsten rod; welding an intermediate glass material to one end of a quartz glass tube; and air-sealing the intermediate glass material and the glass bead with the tungsten rod inserted into a through hole provided in the intermediate glass material.

17. The method for manufacturing a flash discharge tube according to claim 16, wherein in the step of welding the intermediate glass material, the intermediate glass material is welded so as to close one end of the quartz glass tube, and then the through hole is formed in the intermediate glass material, and in the step of air-sealing the intermediate glass material and the glass bead, the tungsten rod is inserted into the through hole, and the intermediate glass material and the glass bead are air-sealed together with the glass bead in contact with the area around the opening of the through hole in the intermediate glass material.

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