Phototherapy device

Abstract

To provide a phototherapy device equipped with a flash discharge tube that has high light emission durability. [Solution] The phototherapy device 200 comprises a flash discharge tube 1 and a control device 220 that controls the emission of light from the flash discharge tube 1. The flash discharge tube 1 comprises a translucent enclosure 10 filled with an inert gas, an anode 20, and a cathode 30. The enclosure 10 includes a quartz glass tube 11, a borosilicate glass material 12 disposed at one end of the quartz glass tube 11 and sealing the anode 20, a borosilicate glass material 13 disposed at the other end of the quartz glass tube 11 and sealing the cathode 30, an intermediate glass material 14 joining the quartz glass tube 11 and the borosilicate glass material 12, and an intermediate glass material 15 joining the quartz glass tube 11 and the borosilicate glass material 13. The intermediate glass materials 14 and 15 are glass materials consisting of one or two layers, respectively. The tip of the cathode 30 is located inside the quartz glass tube 11. The cathode 30 has a sintered pellet 34. In a side view, the sintered pellet 34 overlaps the intermediate glass material 15.

Description

Technical Field

[0001] The present invention relates to a phototherapy device.

Background Art

[0002] Patent Document 1 discloses a flash discharge tube including a first glass tube made of quartz glass, a second glass tube made of borosilicate glass, and an intermediate joint glass tube disposed between the first glass tube and the second glass tube. The intermediate joint glass tube has a coefficient of thermal expansion between the coefficient of thermal expansion of the first glass tube and the coefficient of thermal expansion of the second glass tube.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

[0005] Therefore, an object of the present invention is to provide a phototherapy device including a flash discharge tube with high emission durability.

Means for Solving the Problems

[0006] A phototherapy apparatus according to one aspect of the present invention comprises a flash discharge tube and a control device for controlling the emission of light from the flash discharge tube, wherein the flash discharge tube 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 between the quartz glass tube and the first borosilicate glass material The glass material includes a first intermediate glass material positioned to join the quartz glass tube and the first borosilicate glass material, and a second intermediate glass material positioned between the quartz glass tube and the second borosilicate glass material to join 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 first intermediate glass material when viewed from a direction perpendicular to the axial direction of the quartz glass tube. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a phototherapy device equipped with a flash discharge tube that has high light emission durability. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a side view of a flash discharge tube according to an embodiment. [Figure 2] Figure 2 is a side view showing the mounting position of the trigger winding of the flash discharge tube according to the embodiment. [Figure 3] Figure 3 is an enlarged side view showing the vicinity of the cathode of a flash discharge tube according to an embodiment. [Figure 4] Figure 4 is a side view of the anode of a flash discharge tube according to an embodiment. [Figure 5] Figure 5 is a side view of the cathode of a flash discharge tube according to an embodiment. [Figure 6] Figure 6 is a side view illustrating one step in the manufacturing method of a flash discharge tube according to an embodiment. [Figure 7] FIG. 7 is a side view for explaining one step of a method for manufacturing a flash discharge tube according to an embodiment. [Figure 8] FIG. 8 is a side view for explaining one step of a method for manufacturing a flash discharge tube according to an embodiment. [Figure 9] FIG. 9 is a side view for explaining one step of a method for manufacturing a flash discharge tube according to an embodiment. [Figure 10] 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. [Figure 11] 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. [Figure 12] 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. [Figure 13] 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. [Figure 14] FIG. 14 is a view showing the appearance of a phototherapy device including a flash discharge tube according to an embodiment. [Figure 15] FIG. 15 is a block diagram of a phototherapy device according to an embodiment. [Figure 16] FIG. 16 is a circuit diagram showing a drive circuit included in a control device of a phototherapy device according to an embodiment. [Figure 17] FIG. 17 is a view for explaining the operation of a conventional phototherapy device. [Figure 18A] FIG. 18A is a view for explaining an example of the operation of a phototherapy device according to an embodiment. [Figure 18B] FIG. 18B is a view for explaining an example of the operation of a phototherapy device according to an embodiment. [Figure 19A] FIG. 19A is a view for explaining another example of the operation of a phototherapy device according to an embodiment. [Figure 19B] FIG. 19B is a view for explaining another example of the operation of a phototherapy device according to an embodiment.

Best Mode for Carrying Out the Invention

[0009] Hereinafter, the phototherapy apparatus according to an embodiment 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, components not described in the independent claims are described as optional components.

[0010] Also, each figure is a schematic diagram and is not necessarily drawn precisely. Therefore, for example, scales etc. in each figure do not necessarily match. Also, in each figure, substantially the same configurations are denoted by the same reference numerals, and overlapping descriptions are omitted or simplified.

[0011] Also, 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 ranges that are substantially equivalent, for example, including differences of about several percent.

[0012] Also, in this specification, “translucency” refers to 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.

[0013] Also, in this specification, “main component” means the component having the highest content rate among all components constituting a member. For example, a component having a content rate of 50% or more is a main component. Components are materials, elements, compounds, etc. Also, “member A consists 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.

[0014] Furthermore, in this specification, ordinal numbers such as "first," "second," etc., do not mean the number or order of components unless otherwise specified, but are used to avoid confusion and to distinguish similar components.

[0015] (Embodiment) [composition] First, the configuration of the flash discharge tube according to the embodiment will be explained using Figures 1 to 5.

[0016] 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.

[0017] 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.

[0018] [Envelope] First, the specific configuration of the enclosure 10 will be explained using Figure 1.

[0019] 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.

[0020] The enclosure 10 includes a quartz glass tube 11, borosilicate glass materials 12 and 13, and intermediate glass materials 14 and 15.

[0021] 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.

[0022] 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.

[0023] The borosilicate glass materials 12 and 13 are positioned at both ends of the quartz glass tube 11. Specifically, borosilicate glass material 12 is an example of the first borosilicate glass material, positioned at one end of the quartz glass tube 11 in the axial direction, and sealing the anode 20. Borosilicate glass material 13 is an example of the second borosilicate glass material, positioned at the other end of the quartz glass tube 11 in the axial direction, and sealing 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. 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] The intermediate glass material 14 is an example of a 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.

[0028] 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.

[0029] Intermediate glass materials 14 and 15 are each two-tiered glass materials, also known as tiered 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.

[0030] 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.

[0031] 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 and 1.0 mm or less.

[0032] 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.

[0033] 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 between 3 mm and 6.5 mm, 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 between 1.0 mm and 4.0 mm, with 2.35 mm as an example. The shape of the second glass material 142 is a bottomed cylinder. 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.

[0034] As shown in Figure 3, the wall thickness T2 of the intermediate glass material 15 is less than or equal to the wall thickness T1 of the quartz glass tube 11. For example, the wall thickness T2 is between 50% and 80% of the wall thickness T1. Note that since the intermediate glass material 15 is formed by welding, its wall thickness may not be uniform. The wall thickness T2 of the intermediate glass material 15 can be considered as the wall thickness of the thinnest part of the intermediate glass material 15, i.e., the minimum wall thickness. Alternatively, the wall thickness T2 may be considered, for example, as the wall thickness at the center of the intermediate glass material 15 in the axial direction.

[0035] Furthermore, although not shown in Figure 3, the thickness of the intermediate glass material 14 is less than or equal to the thickness T1 of the quartz glass tube 11. For example, the thickness of the intermediate glass material 14 is between 50% and 80% of the thickness T1. Similar to the intermediate glass material 15, the thickness of the intermediate glass material 14 may not be uniform. The thickness of the intermediate glass material 14 can be considered as the thickness of the thinnest part of the intermediate glass material 14, i.e., the minimum thickness. Alternatively, the thickness of the intermediate glass material 14 may be considered, for example, the thickness at the center of the intermediate glass material 14 in the axial direction.

[0036] The outer and inner diameters of the first glass materials 141 and 151, and the second glass material 152, may be the same, but their shapes and sizes are not particularly limited. Also, Figures 1 and 3 show examples in which the outer diameters of the quartz glass tube 11, the first glass materials 141 and 151, and the second glass material 152 are equal, but this is not the only example. For example, the outer diameter of at least one 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.

[0037] In this embodiment, the number of intermediate glass materials 14 and 15 is two. Therefore, the axial length of the enclosure 10 and the axial length (total length) of each of the flash discharge tubes 1 can be shortened. This makes it possible to realize a compact flash discharge tube 1. The axial length of the flash discharge tube 1 is, for example, 30 mm to 85 mm, but may be 35 mm to 65 mm.

[0038] Intermediate glass materials 14 and 15 have different compositions from borosilicate glass materials 12 and 13, respectively. Specifically, intermediate glass materials 14 and 15 contain SiO2 (silicon dioxide) and B2O3 (boron oxide), respectively. The SiO2 content in intermediate glass material 14 is 75% or more and 90% or less. The B2O3 content in intermediate glass material 14 is 8% or more and 15% or less. The same applies to intermediate glass material 15. The content can be expressed in mass percent.

[0039] In this embodiment, each of the first glass materials 141 and 151, and the second glass materials 142 and 152, contains SiO2 and B2O3. The SiO2 content in each of the first glass materials 141 and 151, and the second glass materials 142 and 152, is 75% or more and 90% or less. The B2O3 content in each of the first glass materials 141 and 151, and the second glass materials 142 and 152, is 8% or more and 15% or less.

[0040] The SiO2 content in the first glass material 141 is higher than that in the second glass material 142. The B2O3 content in the first glass material 141 is lower than that in the second glass material 142. Also, the SiO2 content in the first glass material 151 is higher than that in the second glass material 152. The B2O3 content in the first glass material 151 is lower than that in the second glass material 152.

[0041] By adjusting the SiO2 and B2O3 content, 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 suppress the abrupt change 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 suppress the abrupt change 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.

[0042] The thermal expansion coefficient of the quartz glass tube 11 is 5 × 10⁻⁶. -7 / ℃ or higher, 7×10 -7 It is below / ℃. Furthermore, the thermal expansion coefficients of borosilicate glass materials 12 and 13 are 37 × 10⁻⁶. -7 / ℃ or higher, 42×10 -7 It is below / ℃.

[0043] [Anode and cathode] Next, the specific configurations of the anode 20 and cathode 30 will be explained using Figures 4 and 5.

[0044] 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.

[0045] 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.

[0046] 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, of 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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 between 25% and 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 luminescence. On the other hand, the surface of the sintered pellet 34 becomes rougher, making it more susceptible to melting and scattering due to discharge. By setting the porosity between 25% and 33%, a balance can be struck between stabilizing luminescence and suppressing melting and scattering.

[0052] 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.

[0053] 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.

[0054] 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 located in the axial direction of the quartz glass tube 11 (tip position), the outer diameter R2 of the sintered pellet 34 is less than or equal to the inner diameter R1 of the enclosure 10. In this embodiment, since the tip of the sintered pellet 34 is located inside the quartz glass tube 11, the inner diameter R1 of the enclosure 10 corresponds to the inner diameter R1 of the quartz glass tube 11. For example, the outer diameter R2 is 80% to 90% of the inner diameter R1.

[0055] The inventors manufactured multiple samples of the flash discharge tube 1 and conducted luminescence durability tests on each. The outer diameter R2 of the sintered pellet 34 was varied in each sample. The ratio of the outer diameter R2 to the inner diameter R1 or R3, and the results of the luminescence durability tests for each sample are as follows. Note that the inner diameter R3 is the inner diameter of the enclosure 10 at the tip position when the tip 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.

[0056] [Table 1]

[0057] Luminous durability refers to the ratio of the decrease in light intensity after the luminous durability test to the initial light intensity. In the luminous durability test, the main capacitor capacity was set to 1700 μF, and the voltage applied between 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. All other conditions were common to each sample, except for the ratio of the outer diameter R2 to the inner diameter R1 or R3.

[0058] As shown in Table 1, if the outer diameter R2 is too large or too small compared to the inner diameter R1 or R3, the decrease in light intensity is significant, and the required luminescence durability (specifically, a decrease of 20% or less from the initial light intensity) cannot be achieved. Specifically, good luminescence durability was obtained when the outer diameter R2 was within the range of 80% to 90% of the inner diameter R1 or R3.

[0059] 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 of the quartz glass tube 11 whose axial direction is toward the center. 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.

[0060] 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.

[0061] 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 within the quartz glass tube 11, which has superior heat resistance compared to the borosilicate glass materials 12 and 13 and the intermediate glass materials 14 and 15, the impact of the heat generated by the anode 20 and cathode 30 on the enclosure 10 can be suppressed.

[0062] 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 coefficients of thermal expansion. 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.

[0063] 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.

[0064] 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 to 2.0 mm, and for example, 1.8 mm. 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.

[0065] [Trigger winding] Next, the trigger winding 40 will be explained using Figure 2.

[0066] 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 a metal such as 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.

[0067] 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, and also suppresses variations in the ignition voltage.

[0068] Note that the trigger voltage is an example of a first voltage of 1kV or higher. For example, the trigger voltage is 5kV. Also, the trigger voltage is less than 7.5kV, but it may be 7kV or less, 6kV or less, or 5.5kV or less.

[0069] 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.

[0070] 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. The 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.

[0071] [Manufacturing method] Next, the manufacturing method of the flash discharge tube 1 according to this embodiment will be explained 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.

[0072] First, an anode 20 with a glass bead made of borosilicate glass material 12 fixed to it, and a cathode 30 with a glass bead 132 fixed to it 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.

[0073] 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.

[0074] 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.

[0075] 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 expanded 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.

[0076] 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.

[0077] Next, as shown in Figure 7, with the tungsten rod 21 of the anode 20, which has a glass bead (borosilicate glass material 12), 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.

[0078] 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. After sealing the borosilicate glass material 12 and the intermediate glass material 14, the first glass material 151, the second glass material 152, and the glass tube 131 on the cathode 30 side may be formed.

[0079] Next, as shown in Figure 8, an inert gas is introduced into the enclosure 10 (quartz glass tube 11) using the 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.

[0080] 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.

[0081] 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 strain near the intermediate glass material 15. Note that in Figures 8 and 9, the fixtures supporting the enclosure 10 and cathode 30 (e.g., fixtures made of carbon), and heating devices are omitted from the illustration.

[0082] 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.

[0083] 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. Furthermore, 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. It is also important that, after manufacturing, 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.

[0084] 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.

[0085] 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).

[0086] 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 the thermal expansion coefficients of each type of glass are different. 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.

[0087] 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.

[0088] [Differentiation] Next, several modified examples 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 modified examples 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.

[0089] 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 side compared to 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 part of the intermediate glass material 15, but overlaps with the other 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.

[0090] In the flash discharge tube 1A shown in Figure 10, the tip of the sintered pellet 34 overlaps with the first glass material 151 of the intermediate glass material 15 in a side view. Therefore, at the tip of the sintered pellet 34, the inner diameter of the enclosure 10 becomes the inner diameter R3 of the first glass material 151. That is, in the flash discharge tube 1A, at the tip of the sintered pellet 34, the outer diameter R2 of the sintered pellet 34 is smaller than the inner diameter R3 at the end of the first glass material 151, for example, 80% to 90% of the inner diameter R3. Note that 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.

[0091] 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 becomes the inner diameter R3 of the second glass material 152. That is, in the flash discharge tube 1B, at the tip of the sintered pellet 34, the outer diameter R2 of the sintered pellet 34 is smaller than the inner diameter R3 of the second glass material 152, for example, 80% to 90% of the inner diameter R3. Note that 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.

[0092] 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. Such flash discharge tubes 1A and 1B can achieve the same effects as flash discharge tube 1, such as improved luminescence durability and lower and stabilized ignition voltage.

[0093] In the flash discharge tube 1C shown in Figure 12 and the flash discharge tube 1D shown in Figure 13, the relationship between the inner diameter R1 of the quartz glass tube 11 and the outer diameter R2 of the sintered pellet 34 is different compared to flash discharge tubes 1, 1A, and 1B. Specifically, in flash discharge tubes 1C and 1D, the inner diameter R1 of the quartz glass tube 11 is smaller than the outer diameter R2 of the sintered pellet 34. In flash discharge tube 1C, the arrangement position of the sintered pellet 34 is the same as in flash discharge tube 1A. The ends of the sintered pellet 34 are separated. In flash discharge tube 1D, the arrangement position of the sintered pellet 34 is the same as in flash discharge tube 1B.

[0094] In this way, the tube current can be reduced by decreasing the inner diameter R1 of the quartz glass tube 11. 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 current-resistant design considerations when selecting components for the drive circuit. Furthermore, reducing the tube current reduces the load 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.

[0095] [Phototherapy device] Next, a phototherapy device 200 equipped with a flash discharge tube 1 according to the embodiment will be described.

[0096] Figure 14 shows the external appearance of the phototherapy device 200 equipped with the flash discharge tube 1 according to this embodiment. Figure 15 is a block diagram showing the configuration of the phototherapy device 200 according to this embodiment.

[0097] The phototherapy device 200 shown in Figure 14 is a device used for purposes such as hair growth suppression, hair removal, skin beautification, and cosmetic treatment. The phototherapy device 200 irradiates the skin of the human body with light emitted from the flash discharge tube 1.

[0098] As shown in Figure 15, the phototherapy device 200 comprises a flash discharge tube 1, an operation input unit 210, and a control device 220. The phototherapy device 200 may also be equipped with flash discharge tubes 1A, 1B, 1C, or 1D instead of flash discharge tube 1. Furthermore, the phototherapy device 200 may be equipped with multiple flash discharge tubes 1, 1A, 1B, 1C, or 1D.

[0099] The operation input unit 210 receives operation inputs from the user, such as turning the light discharge tube 1 on and off, and selecting the light output level. The operation input unit 210 may be, for example, one or more physical buttons that the user can operate, but is not limited to these. The operation input unit 210 may be a touch panel, or a microphone that accepts voice input. Alternatively, the operation input unit 210 may be a communication interface that communicates with a terminal device such as a smartphone owned by the user. The operation input unit 210 may receive inputs from the terminal device, such as turning the light discharge tube 1 on and off, and selecting the light output level.

[0100] The control device 220 controls the emission of light from the flash discharge tube 1. In this embodiment, the control device 220 changes the number of times the flash discharge tube 1 emits light according to the light output level selected from a plurality of light output levels.

[0101] As shown in Figure 16, the control device 220 comprises a control unit 221 and a drive circuit 222. Figure 16 is a circuit diagram showing the drive circuit 222 included in the control device 220 of the phototherapy apparatus 200 according to this embodiment.

[0102] The control unit 221 controls the drive circuit 222 based on the operation input received by the operation input unit 210. Specifically, the control unit 221 outputs a light emission signal to the drive circuit 222. The light emission signal is an electrical signal containing pulses. The pulse width of the pulses corresponds to the light emission period of the flash discharge tube 1. The number of pulses included in the light emission signal (number of pulses) corresponds to the number of times the flash discharge tube 1 emits light.

[0103] The control unit 221 has a memory that stores correspondence information, for example, where each of multiple optical output levels is associated with a different number of pulses (number of flashes). For example, in the correspondence information, the higher the optical output level, the more pulses are associated. By referring to the correspondence information, the control unit 221 determines the number of pulses corresponding to the optical output level selected from the multiple optical output levels. The control unit 221 generates and outputs an optical emission signal containing the determined number of pulses. At this time, the pulse width (emission period) is constant regardless of the optical output level. Note that the memory may store multiple correspondence information for each pulse width. The control unit 221 may select one correspondence information from the multiple correspondence information and generate and output an optical emission signal containing pulses of the pulse width corresponding to the selected correspondence information, for a number of pulses corresponding to the optical output level. The control unit 221 can change the pulse width by switching the correspondence information. Alternatively, a single correspondence information may be associated not only with the number of pulses but also with the pulse width. For example, in the correspondence information, the higher the optical output level, the longer the pulse width is associated.

[0104] The control unit 221 is implemented, for example, by an integrated circuit (IC), specifically an LSI (Large Scale Integration). However, the integrated circuit is not limited to an LSI; it may also be a dedicated circuit or a general-purpose processor. For example, the control unit 221 may be a microcontroller. A microcontroller includes, for example, non-volatile memory where the program is stored, volatile memory which is a temporary storage area for executing the program, input / output ports, and a processor for executing the program. Alternatively, the control unit 221 may be a programmable FPGA (Field Programmable Gate Array) or a reconfigurable processor in which the connections and settings of circuit cells within the LSI can be reconfigured.

[0105] The drive circuit 222 is a circuit that causes the flash discharge tube 1 to flash. Flashing means repeatedly alternating between emitting light and not emitting light. The emitting period and the non-emitting period are not particularly limited, but for example, they are 1 microsecond or more and 10 milliseconds or less. The emitting period and the non-emitting period may each be 10 microseconds or more and 1 millisecond or less. Alternatively, the emitting period and the non-emitting period may each be 50 microseconds or more and 500 microseconds or 100 microseconds or more and 300 microseconds or less. The emitting period and the non-emitting period may be the same length or may be of different lengths.

[0106] As shown in Figure 16, the drive circuit 222 includes a switching element 231, a main capacitor 232, and a trigger circuit 240. The drive circuit 222 also includes a power terminal 223 and a ground terminal 224. A predetermined voltage is supplied to the power terminal 223 from a power supply circuit (not shown). The ground terminal 224 is set to ground potential (0V). The power supply circuit includes an AC / DC converter for converting commercial power (AC) to a predetermined DC power.

[0107] The switching element 231 is connected in series between the cathode 30 of the flash discharge tube 1 and ground. The switching element 231 is a current-controlled switching element, such as a transistor like an IGBT (Insulated Gate Bipolar Transistor). The gate (control terminal) of the switching element 231 receives the light emission signal output from the control unit 221. The switching element 231 switches on and off according to the pulses contained in the light emission signal. An amplifier and resistor that amplify the light emission signal may be connected between the control unit 221 and the switching element 231. One of the two main electrodes of the switching element 231 (collector) is connected to the cathode 30, and the other of the two main electrodes (emitter) is connected to the ground terminal 224.

[0108] The main capacitor 232 is an example of a capacitive element connected in series between the anode 20 and ground. The main capacitor 232 is, for example, an electrolytic capacitor. A power supply (not shown) is connected to the main capacitor 232, and when the operation input unit 210 receives a power-on operation, a voltage of a predetermined magnitude is applied to the main capacitor 232.

[0109] The trigger circuit 240 is a circuit that generates a trigger voltage. As shown in Figure 16, the trigger circuit 240 includes a resistor 241, a trigger capacitor 242, and a trigger coil 243.

[0110] Resistor 241 is connected between the power terminal 223 and the trigger capacitor 242. The trigger capacitor 242 is connected between resistor 241 and one end of the primary side of trigger coil 243. The connection point between resistor 241 and trigger capacitor 242 is connected to the main electrode (collector) of switching element 231. One end of the secondary side of trigger coil 243 is connected to the trigger winding 40. The other end of the primary side and the other end of the secondary side of trigger coil 243 are connected to each other and connected to the ground terminal 224. When the operation input unit 210 receives a power-on operation, a predetermined voltage is charged to the trigger capacitor 242 by the current flowing from the power terminal 223 through resistor 241. The voltage charged to the trigger capacitor 242 is an example of a second voltage, for example, 330V or less. The voltage charged to the trigger capacitor 242 may be 300V or less, 280V or less, or 250V or less.

[0111] The drive circuit 222 shown in Figure 16 amplifies the voltage charged in the main capacitor 232 and applies it between the anode 20 and cathode 30 of the flash discharge tube 1. Specifically, the drive circuit 222 amplifies the voltage charged in the main capacitor 232 by a factor of 2 and applies it between the anode 20 and cathode 30. The drive circuit 222 is also called a voltage doubler circuit. For the configuration to amplify the voltage, the drive circuit 222 includes two diodes 251 and 252, a transistor 253, a capacitive element 254, and two resistive elements 255 and 256.

[0112] Diode 251 is connected in series between cathode 30 and switching element 231. Specifically, the anode of diode 251 is connected to cathode 30, and its cathode is connected to the main electrode (collector) of switching element 231. Diode 252 is connected in series between one of the two main electrodes (emitter) of transistor 253 and ground. Specifically, the anode of diode 252 is connected to the emitter of transistor 253, and its cathode is connected to ground terminal 224. A capacitive element 254 is connected in series between the anode of diode 252 and the cathode of diode 251. One of the two main electrodes (collector) of transistor 253 is connected to cathode 30 and the anode of diode 251. The control terminal (base) of transistor 253 is connected to ground terminal 224 via resistor 255. A resistor 256 is also connected between the control terminal (base) and the main electrode (emitter) of transistor 253.

[0113] When the switching element 231 is turned on, a trigger voltage is applied to the outer surface of the enclosure 10, amplifying the voltage charged in the main capacitor 232 by a factor of two and applying it as a ignition voltage between the anode 20 and the cathode 30. Specifically, when the switching element 231 is turned on, the charge stored in the trigger capacitor 242 discharges through the primary side of the trigger coil 243, generating a trigger voltage of 1kV or more on the secondary side of the trigger coil 243. The generated trigger voltage excites the inert gas filled inside the enclosure 10 of the flash discharge tube 1 and the emitter material contained in the sintered pellet 34 of the cathode 30 via the trigger winding 40. This initiates an arc discharge between the anode 20 and the cathode 30. As a result of the arc discharge, the impedance inside the enclosure 10 becomes low, and the charge in the main capacitor 232 is discharged. When the switching element 231 is turned off, the discharge and light emission stop, and the main capacitor 232 is recharged. In other words, the flash discharge tube 1 emits light during the ON period of the switching element 231 and does not emit light during the OFF period. By continuously switching the switching element 231 on and off, the flash discharge tube 1 can be made to blink.

[0114] In this embodiment, stable excitation is possible even at low voltages of less than 7.5kV. While the trigger voltage necessitates insulation measures due to the risk of surface discharge between the trigger and external electrodes, the low trigger voltage in this embodiment makes insulation measures easier.

[0115] The drive circuit provided by the control device 220 is not limited to the drive circuit 222 shown in Figure 16. For example, the control device 220 may include a single circuit that applies the ignition voltage charged in the main capacitor directly between the anode 20 and the cathode 30. Alternatively, the control device 220 may include a voltage multiplier circuit that amplifies the voltage charged in the main capacitor by three times. The voltage multiplier circuit generates a third voltage based on the second voltage charged in the main capacitor and applies the generated third voltage as the ignition voltage between the anode 20 and the cathode 30.

[0116] Next, an example of the operation of the phototherapy device 200 according to this embodiment will be described. First, an example of the operation of a conventional phototherapy device will be described using Figure 17. Figure 17 is a diagram for explaining the operation of a conventional phototherapy device. In Figure 17, the horizontal axis represents the flash time (luminescence period), and the vertical axis represents the light output and current output. Levels 1 to 4 correspond to the light output levels, and a higher number means a higher light output level.

[0117] As shown in Figure 17, in conventional phototherapy devices, the duration of light emission from the flash discharge tube is changed according to the light output level. Specifically, at level 4, which has a high light output level, the emission period is long, and at level 1, which has a low light output level, the emission period is short. At levels 3 and 4, the peak values ​​of the light output and current output are the same, and only the emission period differs.

[0118] Conventional phototherapy devices have high peak light output values, which can cause strong skin irritation, potentially leading to pain or a feeling of heat. In contrast, the phototherapy device 200 according to this embodiment can lower the peak light output value. This reduces skin irritation and suppresses pain and heat.

[0119] Figures 18A and 18B illustrate an example of the operation of the phototherapy device 200 according to this embodiment. Figure 18A represents level 3, which has a high light output level, and Figure 18B represents level 2, which has a low light output level. As can be seen by comparing Figures 18A and 18B, the number of flashes differs when the light output level is different. Specifically, at level 3, there are 4 flashes, while at level 2, there are fewer flashes, only 2. The duration of each flash is the same. Also, the peak value of each flash is the same. That is, the peak value of the light output of the flash discharge tube 1 is substantially constant regardless of the multiple light output levels. In the phototherapy device 200, when the light output level is different, the control device 220 changes the number of flashes for the same peak value and the same flash duration.

[0120] In Figures 18A and 18B, the conventional optical output shown in Figure 17 is represented by a dashed line for comparison. In the phototherapy device 200 according to this embodiment, the peak value of the optical output can be reduced compared to the conventional device. This is because the sintered pellet 34 is positioned to overlap with the intermediate glass material 15 in a side view, making excitation by the trigger voltage easier. In addition, in this embodiment, the melting point of the emitter material is low, and the thermal decomposition activity of the emitter material can be efficiently performed by the heat generated when the cathode 30 is sealed. In this respect as well, excitation of the emitter material is promoted, and the peak value of the optical output can be reduced. By reducing the peak value of the optical output, skin irritation can be reduced, and pain and heat can be suppressed. Conventionally, cooling devices such as Peltier elements were provided to cool the skin in order to suppress pain and heat, but such cooling devices are unnecessary, so the phototherapy device 200 can be made smaller, lighter, and the circuit configuration can be simplified.

[0121] Furthermore, since the peak value of the current output and the lighting voltage are also lower, the time required to charge the main capacitor 232 is also shortened. Rapid charging becomes possible, allowing for repeated illumination in a short period of time. In addition, by increasing the number of illumination cycles, a high light output level can be achieved. Thus, according to this embodiment, by performing continuous illumination of low light intensity at short intervals, a total light output level similar to or higher than that of conventional devices can be achieved. Therefore, effects such as hair growth suppression and skin beautification can be obtained.

[0122] Furthermore, the phototherapy device 200 according to this embodiment may allow for changes in the light emission period. Figures 19A and 19B are diagrams illustrating an example of the operation of the phototherapy device 200 according to this embodiment. Figure 19A represents level 2, where the light output level is high, and Figure 19B represents level 1, where the light output level is low.

[0123] As can be seen by comparing Figure 18B and Figure 19A, even at the same level 2, the total light intensity (integral amount of light emission period and light output) can be made different. For example, the control device 220 may switch between a first operating mode using a short light emission period as shown in Figures 18A and 18B, and a second operating mode using a long light emission period as shown in Figures 19A and 19B. The combination of light output level (number of flashes) and light emission period can be switched according to the user's requests or purpose.

[0124] [Effects, etc.] A phototherapy apparatus according to a first aspect of the present invention is, for example, the phototherapy apparatus 200 described above, and comprises a flash discharge tube 1, 1A, 1B, 1C or 1D, and a control device 220 for controlling the emission of light from the flash discharge tube 1, 1A, 1B, 1C or 1D. The flash discharge tube 1, 1A, 1B, 1C or 1D comprises a translucent enclosure 10 with an inert gas sealed inside, an anode 20 located at one end of the enclosure 10, and a cathode 30 located at the other end of the enclosure 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 made of glass material consisting of one or two layers. The tip of the cathode 30 is located inside the quartz glass tube 11. The cathode 30 has a sintered pellet 34. 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.

[0125] 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 a flash discharge tube 1, 1A, 1B, 1C, or 1D that is less prone to breakage and has high luminescence durability. The phototherapy device according to this embodiment is equipped with a flash discharge tube 1, 1A, 1B, 1C, or 1D with high luminescence durability, thereby improving the reliability and yield of the phototherapy device 200.

[0126] 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 tubes 1, 1A, 1B, 1C, or 1D can be shortened. Thus, a compact phototherapy device 200 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, thus reducing the weight of the phototherapy device 200. In addition, since tungsten is generally expensive, shortening the tungsten rods 21 and 31 can reduce the cost of the phototherapy device 200.

[0127] Furthermore, the heat generated during sealing of the borosilicate glass material 13 and the cathode 30 can cause thermal decomposition activity of the emitter material contained in the sintered pellet 34 of the cathode 30. Sufficient activation of the emitter material allows for a lower ignition voltage and suppression of variations in the ignition voltage. A lower ignition voltage reduces the peak value of the light intensity per emission, thereby reducing the pain and heat that can be inflicted on a person. Since cooling devices such as Peltier elements to suppress pain and heat become unnecessary, the phototherapy device 200 can be made smaller, lighter, and its circuit configuration simplified.

[0128] A phototherapy apparatus according to a second aspect of the present invention is a phototherapy apparatus according to a first aspect, wherein the control device 220 includes a drive circuit 222 that causes the flashing discharge tubes 1, 1A, 1B, 1C, or 1D to flash and emit light.

[0129] This allows for the creation of multiple light output levels by adjusting the number of flashes during blinking. Since it is not necessary to increase the peak light output of each flash, the pain and heat that may be inflicted on a person can be reduced.

[0130] A phototherapy apparatus according to a third aspect of the present invention is a phototherapy apparatus according to a second aspect, wherein the drive circuit 222 includes a switching element 231 connected in series between the cathode 30 and ground, a main capacitor 232 connected in series between the anode 20 and ground, and a trigger circuit 240 that generates a first voltage of 1kV or more. When the switching element 231 is turned on, the first voltage is applied to the outer surface of the enclosure 10, and the second voltage charged in the main capacitor 232, or a third voltage generated based on the second voltage, is applied between the anode 20 and the cathode 30.

[0131] This allows for easy adjustment of the number of flashes by switching the switching element 231 on and off.

[0132] A phototherapy apparatus according to the fourth aspect of the present invention is a phototherapy apparatus according to the third aspect, wherein the first voltage (trigger voltage) is less than 7.5kV, and the voltage applied between the anode 20 and the cathode 30 when the flash discharge tubes 1, 1A, 1B, 1C, or 1D emit light is 250V or more.

[0133] This allows the flash discharge tubes 1, 1A, 1B, 1C, or 1D to emit light stably even with low trigger voltages and low ignition voltages. As a result, continuous emission of low-intensity light at short intervals becomes possible.

[0134] A phototherapy apparatus according to the fifth aspect of the present invention is a phototherapy apparatus according to the third or fourth aspect, wherein the second voltage is 330V or less.

[0135] This allows for a lower ignition voltage.

[0136] A phototherapy apparatus according to the seventh aspect of the present invention is a phototherapy apparatus according to any one of the first to fifth aspects, wherein the control device 220 changes the number of flashes of the flash discharge tubes 1, 1A, 1B, 1C, or 1D according to the light output level selected from a plurality of light output levels.

[0137] This allows for the creation of multiple light output levels by adjusting the number of flashes.

[0138] The phototherapy apparatus according to the eighth aspect of the present invention is a phototherapy apparatus according to the sixth aspect, wherein the peak value of the optical output of the flash discharge tubes 1, 1A, 1B, 1C, or 1D is substantially constant regardless of the multiple optical output levels.

[0139] This means that even at high light output levels, it is not necessary to increase the peak value of the light output, thereby reducing the pain and heat that can be inflicted on people.

[0140] (others) Although the flash discharge tube and phototherapy apparatus according to the present invention have been described above based on the above embodiments, the present invention is not limited to the above embodiments.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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. [Explanation of Symbols]

[0145] 1, 1A, 1B, 1C, 1D flash tube 10 Envelope 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 30 cathode 34 Sintered pellets 40 Trigger winding 200 Phototherapy device 220 Control device 222 Drive Circuit 231 Switching element 232 Main Capacitors 240 Trigger Circuit

Claims

1. A flash discharge tube and The system comprises a control device for controlling the light emission of the flash discharge tube, The aforementioned flash discharge tube is A translucent outer enclosure with an inert gas sealed inside, An anode positioned at one end of the aforementioned enclosure, The enclosure comprises a cathode located at the other end, The aforementioned enclosure is, A quartz glass tube and A first borosilicate glass material is placed at one end of the quartz glass tube and seals the anode, A second borosilicate glass material is placed at the other end of the quartz glass tube and seals the cathode, A first intermediate glass material is placed between the quartz glass tube and the first borosilicate glass material, and joins the quartz glass tube and the first borosilicate glass material. The material includes 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, 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, The sintered body, when viewed from a direction perpendicular to the axial direction of the quartz glass tube, overlaps the first intermediate glass material. Light therapy device.

2. The control device includes a drive circuit that causes the flashing discharge tube to blink and emit light. The phototherapy apparatus according to claim 1.

3. The aforementioned drive circuit is A switching element connected in series between the cathode and ground, A capacitive element connected in series between the anode and ground, It includes a trigger circuit that generates a first voltage of 1 kV or more, When the switching element is turned on, the first voltage is applied to the outer surface of the enclosure, and the second voltage charged to the capacitive element, or the third voltage generated based on the second voltage, is applied between the anode and the cathode. The phototherapy apparatus according to claim 2.

4. The first voltage is less than 7.5 kV. The voltage applied between the anode and the cathode when the flash discharge tube emits light is 250V or more. The phototherapy apparatus according to claim 3.

5. The aforementioned second voltage is 330V or less. The phototherapy apparatus according to claim 3.

6. The control device changes the number of times the flashing discharge tube emits light according to the light output level selected from a plurality of light output levels. The phototherapy device according to any one of claims 1 to 5.

7. The peak value of the optical output of the flash discharge tube is substantially constant regardless of the multiple optical output levels. The phototherapy apparatus according to claim 6.

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