Flash discharge tube and phototherapeutic apparatus

Abstract

To provide a flash discharge tube capable of reducing a whole length.SOLUTION: A flash discharge tube 1 comprises: a light transmissivity package 10 into which an inactive gas is sealed therein; and a pair of discharge electrodes (a positive electrode 20 and a negative electrode 30) that are arranged to both ends of the package 10. The package 10 contains: a quarts glass tube 11; a pair of borosilicate glass tubes 12 and 13 that are arranged to both ends of the quarts glass tube 11, and seal the pair of discharge electrodes; and a pair of intermediate glass materials 14 and 15 that are arranged to between the quarts glass tube 11 and the pair of borosilicate glass tubes 12 and 13, and bond the quarts glass tube 11 and the pair of borosilicate glass tubes 12 and 13. Each of the pair of intermediate glass materials 14 and 15 is a glass material formed by one step or a two steps. Each tip end part of the pair of discharge electrodes is positioned in the quarts glass tube 11.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a flash lamp and a phototherapy device. [Background technology]

[0002] Patent Document 1 discloses a flash lamp including an arc tube made of quartz glass and a pair of electrodes disposed on both ends of the arc tube. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-170327 A Summary of the Invention [Problem to be solved by the invention]

[0004] The flash lamp disclosed in Patent Document 1 has a problem in that it is necessary to secure a long sealed portion between the electrode and the quartz glass tube, which increases the overall length.

[0005] An object of the present invention is to provide a flashlight discharge tube whose overall length can be shortened, and a phototherapy device including the flashlight discharge tube. [Means for solving the problem]

[0006] A flashlight discharge tube according to one embodiment of the present invention comprises a light-transmitting envelope filled with an inert gas, and a pair of discharge electrodes arranged at both ends of the envelope, the envelope including a quartz glass tube, a pair of borosilicate glass materials arranged at both ends of the quartz glass tube and sealing the pair of discharge electrodes, and a pair of intermediate glass materials arranged between the quartz glass tube and each of the pair of borosilicate glass materials and joining the quartz glass tube and the pair of borosilicate glass materials, each of the pair of intermediate glass materials being glass materials consisting of one or two stages, and the tip of each of the pair of discharge electrodes being located within the quartz glass tube.

[0007] A phototherapy device according to one aspect of the present invention includes the flashlight discharge tube according to the above aspect. Effect of the Invention

[0008] According to the present invention, it is possible to provide a flashlight discharge tube whose overall length can be shortened, and a phototherapy device including the flashlight discharge tube. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a flash discharge tube according to an embodiment. [Diagram 2] FIG. 2 is a schematic diagram of an anode of a flash discharge tube according to an embodiment. [Diagram 3] FIG. 3 is a schematic diagram of a cathode of a flash discharge tube according to an embodiment. [Figure 4] FIG. 4 is a schematic diagram showing one step of a method for manufacturing a flashlight discharge tube according to an embodiment. [Diagram 5] FIG. 5 is a schematic diagram showing one step of a method for manufacturing a flashlight discharge tube according to an embodiment. [Figure 6] FIG. 6 is a schematic diagram showing one step of a method for manufacturing a flashlight discharge tube according to an embodiment. [Figure 7] FIG. 7 is a schematic diagram showing one step of a method for manufacturing a flashlight discharge tube according to an embodiment. [Figure 8] FIG. 8 is a schematic diagram of a flash discharge tube according to a modified example of the embodiment. [Figure 9] FIG. 9 is a schematic diagram of a phototherapy device including a flash discharge tube according to an embodiment or a modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The following describes in detail the flash discharge tube and phototherapy device according to the embodiment of the present invention 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, component arrangements, connection forms, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are merely examples and are not intended to limit the present invention. Therefore, among the components in the following embodiments, components that are not described in the independent claims are described as optional components.

[0011] In addition, each figure is a schematic diagram and is not necessarily illustrated precisely. Therefore, for example, the scales in each figure do not necessarily match. In addition, in each figure, substantially the same configurations are given the same reference numerals, and duplicated explanations are omitted or simplified.

[0012] Furthermore, in this specification, terms indicating relationships between elements, terms indicating the shapes of elements, and numerical ranges are not expressions that only express a strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about a few percent.

[0013] In this specification, the term "translucency" refers to the property of transmitting at least a part of incident light. For example, a translucent member can transmit light having an intensity of more than 50% of the light incident on the member.

[0014] In addition, in this specification, ordinal numbers such as "first" and "second" do not refer to the number or order of components, unless otherwise specified, but are used for the purpose of avoiding confusion between and distinguishing between components of the same type.

[0015] (Embodiment) [composition] First, the configuration of a flash discharge tube according to an embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0016] Fig. 1 is a schematic diagram of flash discharge tube 1 according to the present embodiment. Fig. 2 is a schematic diagram of anode 20 of flash discharge tube 1 according to the present embodiment. Fig. 3 is a schematic diagram of cathode 30 of flash discharge tube 1 according to the present embodiment.

[0017] 1, flashlight discharge tube 1 includes an envelope 10, an anode 20, and a cathode 30. Anode 20 and cathode 30 are an example of a pair of discharge electrodes.

[0018] [Envelope] First, a specific configuration of the envelope 10 will be described with reference to FIG.

[0019] The envelope 10 is a light-transmitting envelope filled with an inert gas. The inert gas is specifically a rare gas, for example, xenon gas. The inert gas may be argon gas or krypton gas, or the like. Alternatively, the inert gas may be nitrogen gas. The inert gas may be a single type of gas or a mixed gas.

[0020] The envelope 10 includes a quartz glass tube 11 , a pair of borosilicate glass tubes 12 and 13 , and a pair of intermediate glass members 14 and 15 .

[0021] The quartz glass tube 11 is a tubular member having a space in which an inert gas exists. The quartz glass tube 11 has a straight tube shape. The outer diameter of the quartz glass tube 11 is, for example, 3 mm or more and 6 mm or less, for example, 4.0 mm. The inner diameter of the quartz glass tube 11 is, for example, 1.0 mm or more and 4.0 mm or less, for example, 2.35 mm. The axial length of the quartz glass tube 11 is, for example, 15 mm or more and 60 mm or less. The shape and size of the quartz glass tube 11 are not particularly limited.

[0022] In this embodiment, the quartz glass tube 11 has no trace of inert gas filling. The filling trace means a trace of blocking an opening that penetrates the side surface of the glass tube as a gas inlet and outlet when the inert gas is filled. The filling trace can be formed as a recess or protrusion on the side surface of the glass tube. Since there is no filling trace, the quartz glass tube 11 has a substantially uniform inner diameter and outer diameter.

[0023] The borosilicate glass tubes 12 and 13 are an example of a pair of borosilicate glass materials, and are arranged at both ends of the quartz glass tube 11. Specifically, the borosilicate glass tube 12 is arranged at one end in the axial direction of the quartz glass tube 11, and seals the anode 20. The borosilicate glass tube 13 is arranged at the other end in the axial direction of the quartz glass tube 11, and seals the cathode 30. The borosilicate glass tubes 12 and 13 are in close contact with the anode 20 or the cathode 30, respectively, without any gaps, so that the internal space and the external space do not communicate with each other.

[0024] The borosilicate glass tube 12 includes a glass tube 121 and a glass bead 122. Both the glass tube 121 and the glass bead 122 are glass materials made of borosilicate glass. For example, the composition ratio of the glass tube 121 and the glass bead 122 is the same. The glass tube 121 is an annular member into which the glass bead 122 can be inserted. The glass tube 121 and the glass bead 122 are fused together to seal the anode 20. The glass tube 121 terminates one end of the quartz glass tube 11 and prevents the inert gas in the quartz glass tube 11 from leaking out to the outside. Although the glass tube 121 and the glass bead 122 are drawn separately in FIG. 1, they are fused together to be integrated.

[0025] The borosilicate glass tube 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 are fused together to seal the cathode 30. The glass tube 131 terminates the other end of the quartz glass tube 11 and prevents the inert gas in the quartz glass tube 11 from leaking out to the outside. Although the glass tube 131 and the glass bead 132 are drawn separately in FIG. 1, they are fused together to be integrated. The glass tube 131 and the glass bead 132 have substantially the same configuration as the glass tube 121 and the glass bead 122, respectively.

[0026] The outer diameter of each of the borosilicate glass tubes 12 and 13 is, for example, 1.5 mm or more and 6.0 mm or less, for example, 3.75 mm. The inner diameter of each of the borosilicate glass tubes 12 and 13 is, for example, 1.0 mm or more and 4.9 mm or less, for example, 2.65 mm. The axial length of each of the borosilicate glass tubes 12 and 13 is, for example, 1.5 mm or more and 8.0 mm or less. The outer diameter and inner diameter of each of the borosilicate glass tubes 12 and 13 (glass tube 131) may be the same as the outer diameter and inner diameter of the quartz glass tube 11, but the shape, size, etc. of these are not particularly limited.

[0027] The intermediate glass materials 14 and 15 are disposed between the quartz glass tube 11 and the borosilicate glass tubes 12 and 13, respectively, and join the quartz glass tube 11 to the borosilicate glass tubes 12 and 13. Specifically, the intermediate glass material 14 joins one axial end of the quartz glass tube 11 to the borosilicate glass tube 12 (glass tube 121). The intermediate glass material 15 joins the other axial end of the quartz glass tube 11 to the borosilicate glass tube 13 (glass tube 131).

[0028] Each of the intermediate glass materials 14 and 15 is a glass material consisting of two stages, and is also called a stage seal. Specifically, the 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 tube 12. The first glass material 141 and the second glass material 142 are joined to each other. The 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 tube 13. The first glass material 151 and the second glass material 152 are joined to each other.

[0029] The thickness of each of the intermediate glass materials 14 and 15 in the axial direction is, for example, 1 mm or more and 4 mm or less. The thickness of each of the intermediate glass materials 14 and 15 in the axial direction 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.

[0030] 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 equal to or less than 1.5 mm. The axial thickness of each of the first glass materials 141 and 151 may be equal to or greater than 0.5 mm and equal to or less than 1.0 mm.

[0031] The second glass material 142 joined to the borosilicate glass tube 12 and the second glass material 152 joined to the borosilicate glass tube 13 each have an axial thickness of, for example, 0.5 mm or more and 2.5 mm or less. The axial thickness of each of the second glass materials 142 and 152 may be 0.8 mm or more and 2.0 mm or less. For example, the axial thickness of each of the second glass materials 142 and 152 is thicker than the axial thickness of each of the first glass materials 141 and 151, but is not limited thereto.

[0032] The first glass materials 141 and 151 and the second glass materials 142 and 152 each have a flat tubular shape. Flat means that the thickness (length) in the axial direction is smaller than the outer diameter. The outer diameter of each of the first glass materials 141 and 151 and the second glass materials 142 and 152 is 3 mm or more and 6.5 mm or less, for example, 4.0 mm. The inner diameter of each of the first glass materials 141 and 151 and the second glass materials 142 and 152 is 1.0 mm or more and 4.0 mm or less, for example, 2.3 mm. The outer diameter and inner diameter of each of the first glass materials 141 and 151 and the second glass materials 142 and 152 may be the same as the outer diameter and inner diameter of the quartz glass tube 11, but their shapes, sizes, etc. are not particularly limited.

[0033] In the present embodiment, the number of stages of intermediate glass materials 14 and 15 is two, so that it is possible to shorten the axial length of envelope 10 and the axial length (total length) of each of flashlight discharge tubes 1. This makes it possible to realize a compact flashlight discharge tube 1. The axial length of flashlight 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.

[0034] The intermediate glass materials 14 and 15 contain SiO2 (silicon dioxide) and B2O3 (boron oxide). The SiO2 content in the intermediate glass material 14 is 75% or more and 90% or less. The B2O3 content in the intermediate glass material 14 is 8% or more and 15% or less. The same is true for the intermediate glass material 15. The contents can be expressed in mass%.

[0035] 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.

[0036] The content of SiO2 in the first glass material 141 is higher than the content of SiO2 in the second glass material 142. The content of B2O3 in the first glass material 141 is lower than the content of B2O3 in the second glass material 142.

[0037] By adjusting the contents of SiO2 and B2O3, the thermal expansion coefficients increase in the order of the quartz glass tube 11, the first glass material 141, the second glass material 142, and the borosilicate glass tube 12. The first glass material 141 and the second glass material 142 suppress a sudden change in the thermal expansion coefficient between the quartz glass tube 11 and the borosilicate glass tube 12, and can increase the bonding strength between the glass tubes.

[0038] The thermal expansion coefficient of the quartz glass tube 11 is 5×10 -7 / ℃ or more, 7×10 -7 / °C or less. The thermal expansion coefficient of each of the borosilicate glass tubes 12 and 13 is 37×10 -7 / ℃ or more, 42×10 -7 / ℃ or less.

[0039] The same is true for the first glass material 151 and the second glass material 152. Specifically, the content of SiO2 in the first glass material 151 is higher than the content of SiO2 in the second glass material 152. The content of B2O3 in the first glass material 151 is lower than the content of B2O3 in the second glass material 152. The content of SiO2 and B2O3 in each of the first glass material 151 and the second glass material 152 can be set to the same range as the content of SiO2 and B2O3 in each of the first glass material 141 and the second glass material 142. As a result, the thermal expansion coefficient increases in the order of the quartz glass tube 11, the first glass material 151, the second glass material 152, and the borosilicate glass tube 13. That is, the first glass material 151 and the second glass material 152 suppress a sudden change in the thermal expansion coefficient between the quartz glass tube 11 and the borosilicate glass tube 13, and can increase the bonding strength between the glass tubes.

[0040] [Anode and cathode (a pair of discharge electrodes)] Next, the specific configurations of the anode 20 and the cathode 30 will be described with reference to FIGS.

[0041] 2, the anode 20 includes a tungsten rod 21, an external pin 22, and a joint 23. The joint 23 is a portion formed by welding the tungsten rod 21 and the external pin 22 together.

[0042] The tungsten rod 21 is a rod-shaped conductive member containing tungsten as a main component. The tungsten rod 21 is a lead-in wire or electrode pin of a discharge electrode. The anode 20 is fixed to the envelope 10 by sealing the tungsten rod 21 to the borosilicate glass tube 12. Since tungsten is a high melting point material, the tungsten rod 21 can withstand heat during sealing and discharge. In addition, the thermal expansion coefficient of the tungsten rod 21 is equivalent (for example, in the same order of magnitude) to the thermal expansion coefficient of the borosilicate glass tube 12. This makes it possible to suppress damage to the borosilicate glass tube 12 due to heat during sealing and discharge.

[0043] External pin 22 is a conductive member that receives power for emitting light from flash discharge tube 1. For example, external pin 22 contains nickel as a main component.

[0044] 3, the cathode 30 includes a tungsten rod 31, an external pin 32, a joint 33, and a sintered pellet 34. The cathode 30 has a configuration in which the sintered pellet 34 is added to the configuration of the anode 20. That is, the tungsten rod 31, the external pin 32, and the joint 33 correspond to the tungsten rod 21, the external pin 22, and the joint 23 of the anode 20, respectively. Note that the configuration other than the sintered pellet 34 does not need to be completely the same, and for example, the length of the tungsten rod 31 may be different from the length of the tungsten rod 21.

[0045] The sintered pellet 34 is a sintered member containing an emitter agent that promotes the emission of electrons. Although not shown in FIG. 3, the sintered pellet 34 is fixed after the glass bead 132 is fixed to the tungsten rod 31.

[0046] In this embodiment, as shown in Fig. 1, the tip of each of the anode 20 and the cathode 30 is located inside the quartz glass tube 11. The tip is defined as the direction toward the center in the axial direction of the quartz glass tube 11. Specifically, the tip of the anode 20 is the portion of the tungsten rod 21 opposite the joint 23. The tip of the cathode 30 is the portion of the tungsten rod 31 opposite the joint 33.

[0047] In the cathode 30, at least a portion of the sintered pellet 34 is located inside the quartz glass tube 11. Specifically, the sintered pellet 34 is arranged straddling from the quartz glass tube 11 to the borosilicate glass tube 12. That is, as shown in Fig. 1, when the flash discharge tube 1 is viewed from the side (from a direction perpendicular to the axial direction), the sintered pellet 34 overlaps the intermediate glass material 15.

[0048] The tip portions of the anode 20 and the cathode 30 are portions that are likely to become hot during discharge. By positioning the tip portions of the anode 20 and the cathode 30 within the quartz glass tube 11, which has better heat resistance than the borosilicate glass tubes 12 and 13 and the intermediate glass materials 14 and 15, the effect of the heat generated by the anode 20 and the cathode 30 on the envelope 10 can be suppressed.

[0049] Specifically, distortion remains near the joints between each of intermediate glass materials 14 and 15 and quartz glass tube 11 and borosilicate glass tube 12, because glasses with different softening points are joined together. If heat generated in anode 20 and cathode 30 during use of flash discharge tube 1 is transmitted to the parts where distortion remains, there is a risk of cracks occurring due to thermal shock.

[0050] In contrast, the tip portions of the anode 20 and the cathode 30 are the parts that are most likely to reach high temperatures, and these tip portions are located inside the quartz glass tube 11. That is, by separating the tip portions of the anode 20 and the cathode 30 from the vicinity of the intermediate glass materials 14 and 15, respectively, it is possible to soften the thermal shock that is given to the vicinity of the intermediate glass materials 14 and 15, respectively, and to suppress the occurrence of cracks.

[0051] [Manufacturing method] Next, a method for manufacturing flash discharge tube 1 according to the present embodiment will be described with reference to Figures 4 to 7. Figures 4 to 7 are schematic diagrams showing the steps of the method for manufacturing flash discharge tube 1 according to the present embodiment.

[0052] First, as shown in Fig. 4, the envelope 10 before injecting the inert gas, the anode 20 to which the glass bead 122 is fixed, and the cathode 30 to which the glass bead 132 is fixed are prepared. For example, the tungsten rod 21 and the external pin 22 are welded and fixed, and then the glass bead 122 is sealed to the tungsten rod 21 to form the anode 20. Also, the tungsten rod 31 and the external pin 32 are welded and fixed, and then the glass bead 132 is sealed to the tungsten rod 31. Then, the sintered pellet 34 is fixed to the tungsten rod 31 to form the cathode 30.

[0053] Also, the intermediate glass materials 14 and 15, and the glass tubes 121 and 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 the first glass material 151, the second glass material 152, and the glass tube 131 are formed in this order while the end of the quartz glass tube 11 on the cathode 30 side is heated with a burner. Similarly, the first glass material 141, the second glass material 142, and the glass tube 121 are formed in this order while the quartz glass tube 11 is rotated and the end on the anode 20 side is heated with a burner. 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 141 is brought close to the heated portion at the end of the quartz glass tube 11 to melt the glass rod. The molten glass covers the end of the quartz glass tube 11 along the rotation direction, thereby forming the first glass material 141. The second glass material 142 and the glass tube 121 can also be formed by the same method.

[0054] Next, as shown in FIG. 5, the anode 20 with the glass bead 122 is sealed to the glass tube 121. The sealing of the anode 20 may be performed continuously from the fusion bonding of the quartz glass tube 11 and the intermediate glass material 14 (the first glass material 141 and the second glass material 142). Note that "continuously" means that there is not a sufficient cooling period, and the anode 20 is sealed before the temperature of the intermediate glass material 14 drops and hardens. By sealing the anode 20 before the temperature of the intermediate glass material 14 drops, it is possible to avoid the thermal shock caused when the anode 20 is sealed being applied to the distortion caused inside the intermediate glass material 14 due to the temperature drop. After the anode 20 is sealed, the intermediate glass material 14 is gradually cooled while being heated to suppress the distortion. This suppresses the generation of distortion near the intermediate glass material 14 and suppresses the generation of cracks due to the thermal shock generated during manufacturing and use. After the anode 20 is sealed, the first glass material 151, the second glass material 152, and the glass tube 131 on the cathode 30 side may be formed.

[0055] Next, as shown in FIG. 6, an exhaust sealing device 90 is used to introduce an inert gas into the envelope 10. The exhaust sealing device 90 accommodates the envelope 10 to which the anode 20 is fixed. A gas exhaust path and an air supply path are provided in the space (accommodation space) that accommodates the envelope 10, and valves 91 and 92 are provided on each path. With the envelope 10 accommodated, the valve 91 is opened to exhaust the gas in the accommodation space and create a vacuum in the accommodation space. Thereafter, the valve 91 is closed and the valve 92 is opened to introduce the inert gas into the accommodation space. As a result, the inert gas is introduced into the envelope 10 from the end on the cathode 30 side.

[0056] Next, as shown in FIG. 7, the cathode 30 with the glass bead 132 is sealed to the glass tube 131 of the envelope 10 in an inert gas atmosphere. Specifically, the cathode 30 is inserted into the glass tube 131 and heated, thereby melting and bonding the glass bead 132 and the glass tube 131. After bonding, cooling is started in a state filled with inert gas. After the inert gas is exhausted, the glass tube 131 is slowly cooled in a vacuum insulation state (i.e., cooled while being heated), thereby suppressing distortion occurring near the intermediate glass material 15. Note that in FIGS. 6 and 7, a jig (e.g., a carbon jig) that supports the envelope 10 and the cathode 30, a heating device, and the like are not shown.

[0057] Through the above steps, it is possible to manufacture flashlight discharge tube 1. Note that the above-mentioned method for manufacturing flashlight discharge tube 1 is merely one example, and can be modified as appropriate.

[0058] In flashlight discharge tube 1, at the joints between intermediate glass material 14 and quartz glass tube 11 and borosilicate glass tube 12, a bonding force between the glasses acts around the joint interfaces of the different glasses. In addition, when the molten glass cools (when the viscosity of the glass increases), distortion remains inside the glass. To improve the sealing performance of envelope 10 and prevent breakage, it is important to balance the mutual forces of this bonding force and distortion. Specifically, it is required that the bonding force is greater than the distortion. In addition, it is also important that the temperature in the vicinity of intermediate glass material 14 does not reach a thermal shock temperature at the operating temperature of flashlight discharge tube 1 after manufacture.

[0059] In the manufacturing method of flashlight discharge tube 1 according to the present embodiment, the temperatures of intermediate glass materials 14 and 15 are controlled while being cooled when anode 20 and cathode 30 are sealed, respectively. This makes it possible to suppress distortion occurring near intermediate glass materials 14 and 15. When flashlight discharge tube 1 is in use, anode 20 is more likely to reach a high temperature than cathode 30. For this reason, by performing the formation of intermediate glass material 14 near anode 20 and the sealing of anode 20 consecutively without a cooling period, it is possible to further suppress distortion occurring near intermediate glass material 14. Because distortion can be suppressed, it is possible to join quartz glass tube 11 and borosilicate glass tubes 12 and 13 even if the number of stages of intermediate glass materials 14 and 15 is reduced.

[0060] To increase the bonding strength, the glasses may be heated to a temperature equal to or higher than the cooling point of the temperature-viscosity characteristics of the different glasses. In this case, the bonding surface is softened and the sealing part is expanded or contracted by air blowing to shape it (to make the glass thickness uniform), thereby increasing the bonding area and increasing the bonding strength.

[0061] In addition, when joining ring-shaped sintered glass of different types of glass, the degree of contraction when heat is applied differs for each glass, making joining difficult. Glass has the property of shrinking and becoming round when heated to a temperature at which it deforms (above its softening point). For this reason, even if ring-shaped pieces of different glasses are heated and fused together in a tilted furnace with a temperature gradient, with an intermediate glass sandwiched between them, the amount of volumetric contraction differs because the thermal expansion coefficients of each glass are different. As a result, they cannot be joined by simply applying heat, and tend to come off. Specifically, since the glasses are in point contact with each other, even if they are joined locally, they will pull on each other due to the stress of their distortion, and there is a risk of cracks occurring or coming off starting from the joint.

[0062] In contrast, in the manufacturing method for flashlight discharge tube 1 according to the present embodiment, intermediate glass materials 14 and 15, glass tube 121 of borosilicate glass tube 12, and glass tube 131 of borosilicate glass tube 13 are each formed by melting glass in that order at the end of quartz glass tube 11. This makes it possible to ensure a sufficient bonding area for the different glasses, and to increase the bonding strength.

[0063] [Variations] Next, a modified example of flash discharge tube 1 according to the present embodiment will be described with reference to Fig. 8. Fig. 8 is a schematic diagram of flash discharge tube 2 according to the modified example.

[0064] Compared to flash discharge tube 1 shown in Fig. 1, flash discharge tube 2 shown in Fig. 8 has intermediate glass materials 14A and 15A instead of intermediate glass materials 14 and 15. Intermediate glass materials 14A and 15A each consist of a single layer of glass material. Except for the fact that intermediate glass materials 14A and 15A each consist of a single layer, the configuration of flash discharge tube 2 is the same as the configuration of flash discharge tube 1.

[0065] The intermediate glass materials 14A and 15A each contain SiO2 and B2O3. The SiO2 content in the intermediate glass material 14A is 75% or more and 90% or less, and the B2O3 content in the intermediate glass material 14A is 10% or more and 15% or less. The same is true for the intermediate glass material 15A.

[0066] In this way, in flashlight discharge tube 2, the number of stages of intermediate glass materials 14A and 15A can be minimized, thereby shortening the overall length of flashlight discharge tube 2. Note that, like the two-stage case, one stage of intermediate glass materials 14A and 15A can be formed while suppressing distortion by controlling the temperature during cooling after sealing anode 20 and cathode 30.

[0067] [summary] The flash discharge tube according to the first aspect of the present invention is, for example, the flash discharge tube 1 or 2 described above, and includes a light-transmitting envelope 10 filled with an inert gas, and a pair of discharge electrodes (anode 20 and cathode 30) arranged at both ends of envelope 10. Envelope 10 includes a quartz glass tube 11, a pair of borosilicate glass tubes 12 and 13 arranged at both ends of quartz glass tube 11 and sealing the pair of discharge electrodes, respectively, and a pair of intermediate glass members arranged between quartz glass tube 11 and each of the pair of borosilicate glass tubes 12 and 13 and joining quartz glass tube 11 and the pair of borosilicate glass tubes 12 and 13. The pair of intermediate glass members are intermediate glass members 14A and 15A consisting of one stage, or intermediate glass members 14 and 15 consisting of two stages. The tip portions of the pair of discharge electrodes are located inside quartz glass tube 11.

[0068] In this way, since the number of stages of each intermediate glass material is two or less, the overall length of flash discharge tube 1 or 2 can be shortened. Therefore, a small-sized flash discharge tube 1 or 2 can be realized. Furthermore, since the number of stages of each intermediate glass material is two or less, the lengths of anode 20 and cathode 30 can also be shortened. Specifically, since tungsten rods 21 and 31 can be shortened, the weight of flash discharge tube 1 or 2 can be reduced. Furthermore, since tungsten is generally expensive, by shortening tungsten rods 21 and 31, the cost of flash discharge tube 1 or 2 can be reduced.

[0069] Furthermore, the respective tips of anode 20 and cathode 30, which become hot during use, can be separated from the vicinity of the intermediate glass materials (specifically, intermediate glass materials 14 and 15, or intermediate glass materials 14A and 15A), thereby preventing thermal shock from being applied to the vicinity of the intermediate glass materials. This prevents cracks from occurring in the vicinity of the intermediate glass materials, thereby realizing flashlight discharge tube 1 or 2 that is less likely to break.

[0070] A flashlight discharge tube according to a second aspect of the present invention is a flashlight discharge tube according to the first aspect, in which the axial thickness of each of the pair of intermediate glass materials 14 and 15, or each of the pair of intermediate glass materials 14A and 15A, is 1 mm or more and 4 mm or less.

[0071] This makes it possible to shorten the overall length of the flash discharge tube according to this embodiment.

[0072] A flashlight discharge tube according to a third aspect of the present invention is the flashlight discharge tube according to the first or second aspect, in which quartz glass tube 11 has no trace of inert gas sealed therein.

[0073] As a result, there are no sealing marks that may hinder the transmission of light, so that light can be emitted uniformly in the circumferential direction of the quartz glass tube 11.

[0074] A flashlight discharge tube according to a fourth aspect of the present invention is a flashlight discharge tube according to any one of the first to third aspects, in which intermediate glass material 14 includes a first glass material 141 joined to quartz glass tube 11 and a second glass material 142 joined to borosilicate glass tube 12, and intermediate glass material 15 includes a first glass material 151 joined to quartz glass tube 11 and a second glass material 152 joined to borosilicate glass tube 13.

[0075] In this way, by making the number of stages of the intermediate glass materials 14 and 15 two, it is possible to gradually reduce the difference in thermal expansion coefficient between the quartz glass tube 11 and the borosilicate glass tubes 12 and 13. This makes it possible to suppress the occurrence of cracks when a thermal shock is applied.

[0076] A flashlight discharge tube according to a fifth embodiment of the present invention is the flashlight discharge tube according to the fourth embodiment, in which the axial thickness of each of first glass members 141 and 151 is greater than 0 mm and equal to or less than 1.5 mm.

[0077] This allows the thickness of intermediate glass members 14 and 15 to be thin, and the overall length of the flash discharge tube according to this embodiment to be shortened.

[0078] A flashlight discharge tube according to a sixth embodiment of the present invention is the flashlight discharge tube according to the fourth embodiment, in which the axial thickness of each of second glass members 142 and 152 is not less than 0.5 mm and not more than 2.5 mm.

[0079] This allows the thickness of intermediate glass members 14 and 15 to be thin, and the overall length of the flash discharge tube according to this embodiment to be shortened.

[0080] A flashlight discharge tube according to a seventh aspect of the present invention is a flashlight discharge tube according to any one of the first to sixth aspects, in which each of the pair of discharge electrodes includes tungsten rods 21 and 31 sealed by a pair of borosilicate glass tubes 12 and 13, respectively.

[0081] As a result, since the difference in thermal expansion coefficient between borosilicate glass and tungsten is small, damage to the borosilicate glass tubes 12 and 13 due to heat generated during sealing and use can be suppressed.

[0082] A flashlight discharge tube according to an eighth aspect of the present invention is the flashlight discharge tube according to any one of the first to seventh aspects, in which the thermal expansion coefficient of quartz glass tube 11 is 5×10 -7 / ℃ or more, 7×10 -7 / °C or less, and the thermal expansion coefficient of each of the borosilicate glass tubes 12 and 13 is 37×10 -7 / ℃ or more, 42×10 -7 / ℃ or less.

[0083] A flashlight discharge tube according to a ninth aspect of the present invention is the flashlight discharge tube according to any one of the first to eighth aspects, in which intermediate glass materials 14 and 15 each contain SiO2 and B2O3, the SiO2 content in intermediate glass material 14 is 75% or more and 90% or less, and the B2O3 content in intermediate glass material 14 is 8% or more and 15% or less. The same is true for each of intermediate glass materials 15, 14A, and 15A.

[0084] This makes it possible to easily reduce the difference in thermal expansion coefficient between the quartz glass tube 11 and the borosilicate glass tubes 12 and 13 by adjusting the composition of the intermediate glass material.

[0085] A phototherapy device according to a tenth aspect of the present invention is, for example, a phototherapy device 3 shown in Fig. 9, and includes a flashlight discharge tube according to any one of the first to ninth aspects. Fig. 9 is a schematic diagram of a phototherapy device 3 including a flashlight discharge tube 1 or 2 according to an embodiment or a modification.

[0086] This allows the overall length of flash discharge tube 1 or 2 to be shortened, making it possible to realize a compact phototherapy device.

[0087] (others) Although the flash discharge tube and phototherapy device according to the present invention have been described based on the above-mentioned embodiment, the present invention is not limited to the above-mentioned embodiment.

[0088] For example, flashlight discharge tube 1 or 2 may include a trigger electrode that controls the discharge timing. The trigger electrode is, for example, a transparent conductive film formed on the surface of quartz glass tube 11. When a high voltage of several kV is applied to the trigger electrode, a part of the inert gas can be ionized, and emission of electrons from cathode 30 can be promoted.

[0089] Also, for example, a molybdenum rod may be used instead of the tungsten rods 21 and 31 as the lead-in wires of the anode 20 and the cathode 30. In this case, an aluminosilicate glass tube may be used instead of the borosilicate glass tubes 12 and 13. This can improve adhesion with the molybdenum rod, and can improve the sealing of the inert gas into the envelope 10.

[0090] The present invention may also be realized as a light emitting device, a light source device, or an illumination device, etc., that includes the flash discharge tube 1 or 2. The light emitting device is, for example, a strobe device for a camera. The present invention may also be realized as a camera that includes the flash discharge tube 1 or 2.

[0091] In addition, the present invention also includes forms obtained by applying various modifications to each embodiment that a person skilled in the art may think of, and forms realized by arbitrarily combining the components and functions of each embodiment within the scope that does not deviate from the spirit of the present invention. [Explanation of symbols]

[0092] 1, 2 Flash discharge tube 3 Phototherapy device 10 Envelope 11 Quartz glass tube 12, 13 Borosilicate glass tube 14, 14A, 15, 15A Intermediate glass material 20 Anode (discharge electrode) 21, 31 Tungsten rod 30 Cathode (discharge electrode) 141, 151 First Glass Material 142, 152 Second glass material

Claims

1. a light-transmitting envelope having an inert gas sealed therein; A pair of discharge electrodes disposed at both ends of the envelope; The envelope is A quartz glass tube; A pair of borosilicate glass members are disposed at both ends of the quartz glass tube and seal the pair of discharge electrodes, respectively; a pair of intermediate glass members disposed between the quartz glass tube and each of the pair of borosilicate glass members and joining the quartz glass tube and the pair of borosilicate glass members; Each of the pair of intermediate glass materials is a glass material having one or two layers, The tip of each of the pair of discharge electrodes is located within the quartz glass tube. Flash discharge tube.

2. The thickness of each of the pair of intermediate glass materials in the axial direction is 1 mm or more and 4 mm or less.

2. The flash discharge tube according to claim 1.

3. The quartz glass tube has no trace of the inert gas sealed therein.

2. The flash discharge tube according to claim 1.

4. Each of the pair of intermediate glass members is A first glass material joined to the quartz glass tube; a second glass material bonded to one of the pair of borosilicate glass materials; The flash discharge tube according to any one of claims 1 to 3.

5. The axial thickness of the first glass material is greater than 0 mm and less than or equal to 1.5 mm.

5. The flash discharge tube according to claim 4.

6. The axial thickness of the second glass material is 0.5 mm or more and 2.5 mm or less.

5. The flash discharge tube according to claim 4.

7. Each of the pair of discharge electrodes includes a tungsten rod sealed by the pair of borosilicate glass materials. The flash discharge tube according to any one of claims 1 to 3.

8. The thermal expansion coefficient of the quartz glass tube is 5×10 －７ / ℃ or more, 7×10 －７ / °C or less, The thermal expansion coefficient of the borosilicate glass material is 37×10 －７ / ℃ or more, 42 x 10 －７ / ° C. or less, The flash discharge tube according to any one of claims 1 to 3.

9. The intermediate glass material is SiO ２ and B ２ O ３ Including, SiO in the intermediate glass material ２ The content of is 75% or more and 90% or less, B in the intermediate glass material ２ O ３ The content of is 8% or more and 15% or less. The flash discharge tube according to any one of claims 1 to 3.

10. A phototherapy device comprising the flash discharge tube according to any one of claims 1 to 3.

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