Flash discharge lamp and flash irradiation apparatus

Abstract

To provide a flush discharge lamp capable of suppressing the blackening of a trigger tube, and a flash irradiation apparatus.SOLUTION: A flush discharge lamp includes a light-transparent light-emitting tube extending in a first direction, a pair of electrodes arranged to face each other in the first direction inside the light-emitting tube, a trigger tube arranged to extend across the pair of electrodes along outside of the light-emitting tube. The trigger tube includes a conductive member extending in the first direction, and a light-transparent insertion tube extending in the first direction and housing at least a portion of the conductive member. The insertion tube has a plurality of shrink parts along the first direction. In the shrink part, a portion of the inner circumferential surface protrudes towards the conductive member in an area between a pair of electrodes facing each other.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] In the flash annealing process for semiconductor substrates, the workpiece is often heated by flashing a lamp (also called a "flash discharge lamp" or "flash lamp") at a relatively high energy for a short period of time of 10 msec or less.

[0003] To make the lamp flash, first, a certain voltage is applied to a capacitor connected to the lamp in advance to charge it and store the charge used for the current during the flash, and second, a high-frequency voltage called a trigger voltage is applied to the outer surface of the lamp, causing a dielectric breakdown between the electrodes inside the lamp, resulting in the flash.

[0004] The trigger voltage is often applied to a conductor that is fixed by wrapping it around the outside of the lamp, generating a barrier discharge inside the lamp. In general discharge lamps, including flash discharge lamps, the conductor and the lamp are fixed in contact with each other by wrapping a metal wire around the outer periphery of the arc tube (for example, Patent Document 1).

[0005] On the other hand, in lamps that emit a flash under high energy as described above, if a wire is placed on the outer surface of the lamp, the wire may be cut by the impact of the lamp flash, or the wire may become misaligned, or the wire may become hot enough to melt, resulting in a deterioration in flash performance during use of the lamp.

[0006] In addition, the wire components were heated and evaporated during the flash, causing problems such as contaminating the lamp house and workpiece, or adhering to the outside of the light-emitting tube and altering the quartz glass, causing the lamp to explode (see Patent Document 2).

[0007] To address the above problem, a technology has been proposed that uses a conductor equivalent to the wire (also called a "trigger tube") sealed in a sealed container made of a dielectric material such as glass (for example, Patent Documents 2 to 4). The trigger tube is fixed so that the outer surface of the container is in contact with the outer surface of the lamp. When a high-frequency voltage is applied to the trigger tube in this state, the lamp can flash in the same way as when a wire is used, without the above-mentioned problems occurring. By using this technology, it is possible to prevent the above-mentioned positional deviation, contamination, and recrystallization even when the lamp flashes.

[0008] Patent documents 2 to 4 describe a structure in which an electrode rod made of a high-melting point metal is sealed inside the trigger tube container, and also describe that it is desirable for the inside of the trigger tube container to be in a vacuum state or filled with an inert gas. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2010-10139 A [Patent Document 2] JP 2003-203606 A [Patent Document 3] JP 2009-170208 A [Patent Document 4] JP 2014-2952 A Summary of the Invention [Problem to be solved by the invention]

[0010] In recent years, the field of semiconductor integrated circuits has seen a dramatic increase in density and definition, and due to the constraints of substrate area, circuits are stacked in a three-dimensional structure on a substrate, and there is also a trend for the thickness of each stacked layer to become smaller. In order to manufacture such products, there is a demand for the flash annealing process to reduce the heat input depth during heating. Specifically, measures are taken to reduce the heat input depth by shortening the flash time of the lamp.

[0011] Generally, when the flash duration is shortened under the condition that the lamp input energy per flash is constant, the energy consumption per flash duration increases, and the load on the quartz tube and electrodes that make up the lamp increases. This increases the possibility of the lamp exploding or failing to light relatively early, so it is necessary to pay particular attention to the lamp size, shape of each part, cooling conditions, etc. when optimizing.

[0012] Similarly, as the flash duration becomes shorter, the load on the trigger tube also increases. When lamp lighting tests were repeated under conditions of short flash duration, blackening of the inner surface of the trigger tube case, which was previously seen at the end of its life, occurred relatively early. The blackened area absorbs the light emitted from the lamp, resulting in a problem of lower light intensity and distribution uniformity on the irradiated work surface compared to when there is no blackening.

[0013] In view of the above-mentioned problems, an object of the present invention is to provide a flash discharge lamp and a flash irradiation device capable of suppressing blackening of the trigger tube. [Means for solving the problem]

[0014] The flash discharge lamp according to the present invention comprises: an arc tube extending in a first direction and transparent to light; a pair of electrodes disposed opposite each other in the first direction inside the arc tube; a trigger tube disposed along the outside of the light emitting tube and extending between the pair of electrodes; The trigger tube is A conductive member extending along the first direction; an insertion tube that is transparent to light and extends along the first direction and has at least a portion of the conductive member housed therein; The insertion tube has a plurality of shrink portions along the first direction in a region facing the pair of electrodes, the shrink portions being parts of an inner circumferential surface that protrude toward the conductive member.

[0015] In the flash discharge lamp, the conductive member has a base end supported on one end of the insertion tube and a tip end not in contact with the other end of the insertion tube, A configuration may be adopted in which the shrink portion closest to the tip among the plurality of shrink portions is closer to the tip than the center between the pair of electrodes.

[0016] In the flash discharge lamp, The configuration may also satisfy the relationship Amax≦D / N, where D is the distance between the pair of electrodes, N is the number of the shrunk portions (N is a natural number greater than or equal to 2), and Amax is the maximum spacing between the multiple shrunk portions.

[0017] In the flash discharge lamp, The insertion tube may be configured to include three or more of the shrink portions.

[0018] In the flash discharge lamp, The conductive member may be made of tungsten or molybdenum.

[0019] In the flash discharge lamp, The conductive member may be coated with a platinum group metal.

[0020] A flashlight irradiation device according to the present invention includes the above-mentioned flashlight discharge lamp.

[0021] The flashlight irradiation device according to the present invention may be configured to include either a single flashlight discharge lamp or a plurality of such lamps.

[0022] The present inventors speculate as follows about the cause of blackening of the trigger tube. (1) The shortened flash duration causes the operating temperature of conductive parts to increase more than before. (2) When the lamp is in operation, the heated conductive member comes into contact with part of the inner surface of the glass insertion tube. (3) The glass in the area where it comes into contact with the conductive member becomes overheated, and some of it melts and adheres to the conductive member. (4) As a result of (3), oxygen is released from the glass adhering to the inner surface of the insertion tube and the conductive parts, and reacts with the conductive parts to form oxides. (5) (1) causes (3) and (4) to occur early, resulting in the blackening of the conductive parts. The blackened parts absorb a large amount of light emitted from the lamp, causing a further increase in operating temperature. (6) The steps (3) to (5) are repeated with each flash, causing the blackened area to grow. Some of the blackened material also adheres to the inner surface of the insertion tube.

[0023] In order to prevent blackening of the trigger tube, a shrink section is provided on the insertion tube, part of the inner circumferential surface of which protrudes toward the conductive member. This restricts the vibration of the conductive member when the lamp is in operation, and limits the area where the conductive member comes into contact with the inner surface of the insertion tube to the shrink section, so that blackening can be concentrated only on the shrink section. In addition, by providing multiple shrink sections, the load per shrink section is reduced, so the amount of blackening per shrink section can be suppressed. As a result, the amount of blackening of the trigger tube can be suppressed even after long-term use.

[0024] In addition, by positioning the multiple shrink sections that are closest to the tip of the conductive member closer to the tip of the conductive member than the center between the pair of electrodes, the movement of the tip of the conductive member, which is prone to large vibrations, can be effectively regulated.

[0025] Furthermore, when the distance between a pair of electrodes is D, the number of shrunk sections is N (N is a natural number greater than or equal to 2), and the maximum spacing between the multiple shrunk sections is Amax, the vibration of the conductive member between the shrunk sections can be appropriately regulated by satisfying the relationship Amax≦D / N.

[0026] In addition, the conductive member is made of tungsten or molybdenum, so that it is difficult to melt even at high temperatures, and is coated with a metal belonging to the platinum group, so that the conductive member is protected from contact with oxygen desorbed from the insertion tube, and thus oxidation of the conductive member is suppressed. [Brief description of the drawings]

[0027] [Figure 1] FIG. 2 is a schematic cross-sectional view of an embodiment of a flashlight irradiation device when viewed in the Y direction. [Diagram 2] A drawing showing only the flash discharge lamp of FIG. 1 [Diagram 3] Enlarged view of area III in Figure 2 [Figure 4] Diagram showing the configuration of the lighting circuit for verification experiments DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The following description will discuss embodiments of a flash discharge lamp and a flash irradiation device according to the present invention with reference to the drawings. Note that the following drawings are schematic illustrations, and the dimensional ratios in the drawings do not necessarily match the actual dimensional ratios, and the dimensional ratios between the drawings do not necessarily match.

[0029] Fig. 1 is a schematic cross-sectional view of one embodiment of a flash light irradiation device 1 when viewed in the Y direction, and Fig. 2 is a drawing illustrating only the flash light discharge lamp 10 of Fig. 1. Fig. 3 is a drawing illustrating an enlarged region III of Fig. 2. As shown in Fig. 1, the flash light irradiation device 1 of this embodiment includes a flash light discharge lamp 10, a reflecting member 20, and a support base 30 on which a workpiece W1 is placed. Note that for convenience of illustration, only one flash light discharge lamp 10 is shown in Fig. 1, but the flash light irradiation device 1 may be equipped with a plurality of flash light discharge lamps 10.

[0030] 1, the direction along the tube axis of the arc tube 11 is defined as the X direction, the direction in which the flash discharge lamp 10 faces the workpiece W1 is defined as the Z direction, and the direction perpendicular to the X direction and the Z direction is defined as the Y direction. The X direction corresponds to the first direction.

[0031] In addition, in this specification, when expressing a direction, if there is a distinction between positive and negative directions, the direction is described with a positive or negative sign, such as "+Z direction" and "-Z direction." When expressing a direction without distinguishing between positive and negative directions, the direction is simply described as "Z direction."

[0032] The reflecting member 20 has a reflecting surface 21 that reflects the light L1 emitted from the flash discharge lamp 10, and is disposed so as to reflect the light L1 emitted from the flash discharge lamp 10 and traveling toward the +Z side toward the -Z side, as shown in Fig. 1. Note that the size, shape, etc. of the reflecting member 20 shown in Fig. 1 are merely examples. The reflecting member 20 is, for example, an aluminum (Al) plate.

[0033] The support table 30 is a base having a plurality of pins 30a on which the workpiece W1 is placed. The configuration of the support table 30 supporting the workpiece W1 shown in Fig. 1 is merely one example, and as long as the workpiece W1 can be stopped or fixed at a predetermined position, the support table 30 may be configured to support the workpiece W1 by hooking the outer edge of the workpiece W1. The distance between the flash discharge lamp 10 and the workpiece W1 in the Z direction is appropriately adjusted depending on the type of the workpiece W1, the processing step, etc., but is set to 30 mm in this embodiment.

[0034] The flash discharge lamp 10 includes an arc tube 11, a pair of electrodes (12p, 12n), and a trigger tube 13.

[0035] The arc tube 11 is a quartz glass tube filled with a light emitting gas, has a straight tube shape extending in the X direction, and is transparent to light L1. The arc tube 11 includes a pair of electrodes (12p, 12n) disposed on the inside facing each other in the X direction. The arc tube 11 of this embodiment has a length of 580 mm in the X direction, an outer diameter of 25 mm, and an inner diameter of 20 mm when viewed in the X direction.

[0036] The light emitting gas sealed in arc tube 11 is, for example, xenon gas. The pressure of the xenon gas sealed in arc tube 11 is, for example, 60 kPa at room temperature. When the light emitting gas sealed in arc tube 11 is xenon gas, light with a wavelength of 200 to 1100 nm is generated by discharge.

[0037] The pair of electrodes (12p, 12n) are arranged such that the distance between them in the X direction is 500 mm. In this embodiment, the electrodes (12p, 12n) are made of lanthana tungsten and have an outer diameter of 10 mm. Note that the shapes of the electrodes (12p, 12n) shown in Figs. 1 and 2 are merely examples and are not limited to these shapes. The electrodes (12p, 12n) are connected to a lamp lighting circuit (not shown) via power supply lines (12a, 12a).

[0038] 1 and 2, a trigger tube 13 is provided on the outer wall surface on the +Z side of the light emitting tube 11. The position where the trigger tube 13 is provided may be on the -Z side of the light emitting tube 11, but is preferably on the +Z side of the light emitting tube 11 in consideration of the energy loss of the light L1 emitted from the light emitting tube 11 and traveling directly toward the workpiece W1.

[0039] The trigger tube 13 includes a conductive member 14 extending along the X direction, and an insertion tube 15 that extends along the X direction and has at least a portion of the conductive member 14 housed inside.

[0040] The conductive member 14 is made of, for example, tungsten or molybdenum. The conductive member 14 is in the form of a round bar with an outer diameter of 1 mm and a total length of 540 mm. As shown in FIG. 2, a sealing molybdenum foil 16 is electrically connected to one end of the conductive member 14. A pin 17 is welded to one end of the molybdenum foil 16. The pin 17 is made of, for example, molybdenum. The pin 17 is in the form of a round bar with an outer diameter of 1 mm. The pin 17 is electrically connected to a trigger circuit (described later) via a lead wire, and power is supplied from the outside of the insertion tube 15 to the conductive member 14 inside.

[0041] The insertion tube 15 of this embodiment has an outer diameter of 4 mm and an inner diameter of 2 mm when viewed in the X direction, and a total length of 570 mm. The insertion tube 15 has a conductive member 14 with one end cut off housed in the inner space, and is shrink-sealed at a portion where a sealing molybdenum foil 16 to which one end of the conductive member 14 is welded is disposed so that the space is substantially in a vacuum state. As a result, the base end 14a of the conductive member 14 is fixed to one end of the insertion tube 15. Meanwhile, the tip 14b of the conductive member 14 is not in contact with the other end of the insertion tube 15, and the conductive member 14 is supported in a cantilever state inside the insertion tube 15. The tip 14b of the conductive member 14 is separated by 10 mm from the electrode 12p.

[0042] The space inside the insertion tube 15 may be filled with an inert gas and hermetically sealed. Also, as long as the lighting operation can be performed without any problems, the space inside the insertion tube 15 does not need to be hermetically sealed.

[0043] The insertion tube 15 in this embodiment is made of quartz glass, just like the arc tube 11. However, the arc tube 11 and the insertion tube 15 may be made of different materials, and may be spaced apart from each other as long as they are arranged close to each other. Note that both the arc tube 11 and the insertion tube 15 do not have to be made of quartz glass.

[0044] The arc tube 11 and the insertion tube 15 are fixed in a lamp house (not shown) using a dedicated fixing jig (not shown). The fixing jig is made of, for example, ceramic. The insertion tube 15 is in contact with the outer surface of the arc tube 11, and is arranged so that the central axes of the arc tube 11 and the insertion tube 15 are approximately parallel.

[0045] As shown in FIG. 2, the insertion tube 15 has shrink parts 15a to 15c, which are parts of the inner circumferential surface protruding toward the conductive member 14 in a region facing between the pair of electrodes (12p, 12n). The shrink parts 15a to 15c are formed by partially heating and shrinking the insertion tube 15 with oxyhydrogen flame or the like. As shown in FIG. 2 and FIG. 3, the inner diameter of the shrink parts 15a to 15c is smaller than the other parts and larger than the outer diameter of the conductive member 14. The inner diameter of the shrink parts 15a to 15c is about 1.5 mm. The total length of the shrink parts 15a to 15c in the X direction is about 5 mm. A plurality of the shrink parts 15a to 15c are provided along the X direction. In this embodiment, three shrink parts 15a to 15c are provided.

[0046] The shrink parts 15a to 15c protrude toward the conductive member 14 and are close to the conductive member 14. Here, "close" is used to mean that they are in contact with each other or that they are arranged at a distance smaller than the thickness of the tube wall of the insertion tube 15. The shrink parts 15a to 15c are located in an area facing between the electrodes (12p, 12n) from which strong light is emitted during a flash, and have a smaller inner diameter than the surrounding area. Since the shrink parts 15a to 15c are in contact with the conductive member 14 more frequently than the surrounding area during operation, more blackening occurs near the inner surface of the shrink parts 15a to 15c than the surrounding area. That is, the shrink parts 15a to 15c restrict the vibration of the conductive member 14 during lamp operation and limit the area where the conductive member 14 contacts the inner surface of the insertion tube 15 to the shrink parts 15a to 15c, so that blackening can be concentrated only on the shrink parts 15a to 15c. In addition, by providing a plurality of shrink portions 15a-15c, the load per each of the shrink portions 15a-15c is reduced (distributed), so that the amount of blackening per each of the shrink portions 15a-15c can be suppressed. As a result, the amount of blackening of the trigger tube 13 can be suppressed even after the flash discharge lamp 10 is used for a long time.

[0047] Of the multiple shrink parts 15a to 15c, the shrink part 15a closest to the tip 14b is preferably closer to the tip 14b than the center between the pair of electrodes (12p, 12n). This makes it possible to effectively restrict the movement of the tip 14b of the conductive member 14, which is prone to large vibrations. The shrink part 15a is located at a position 20 mm away from the tip 14b of the conductive member 14.

[0048] In addition, regarding the arrangement of the multiple shrink portions 15a to 15c, it is preferable to satisfy the relationship Amax≦D / N, where D is the distance between a pair of electrodes (12p, 12n), N is the number of the shrink portions 15a to 15c (N is a natural number equal to or greater than 2), and Amax is the maximum distance between the multiple shrink portions 15a to 15c. Here, the distance D between the pair of electrodes (12p, 12n) is the shortest distance between the pair of electrodes (12p, 12n). In addition, the distance between the shrink portions 15a to 15c is the distance between the centers of the shrink portions 15a to 15c. By satisfying the relationship Amax≦D / N, it is possible to appropriately regulate the vibration of the conductive member 14 between the shrink portions 15a to 15c.

[0049] In this embodiment, the number N of the shrink portions 15a to 15c is 3, and the distance A1 between the shrink portions 15a and 15b is equal to the distance A2 between the shrink portions 15b and 15c, ie, A1=A2=Amax.

[0050] Next, a verification experiment was conducted to compare the occurrence of blackening in the trigger tube 13 between a flash discharge lamp 10 equipped with an insertion tube 15 having multiple shrink portions and a flash discharge lamp equipped with an insertion tube 15 having one shrink portion, and the details of the experiment will be described below.

[0051] [Verification experiment 1]

[0052] Example 2 Example 2 is the flash discharge lamp 10 of the above-mentioned embodiment. The distance D between the pair of electrodes (12p, 12n) was 500 mm, and the intervals between the three shrunk parts were each 163 mm. The shrunk part closest to the tip 14b of the conductive member 14 was located 20 mm away from the tip 14b of the conductive member 14.

[0053] Example 1 Example 1 is similar to Example 2, except that there were two shrunk parts. The distance between the two shrunk parts was 245 mm. The shrunk part closest to the tip 14b of the conductive member 14 was located 20 mm away from the tip 14b of the conductive member 14.

[0054] (Comparative Example) The comparative example was the same as Example 2, except that there was one shrunk portion. The one shrunk portion was located 20 mm away from the tip 14b of the conductive member 14.

[0055] (conditions) 4 is a diagram showing the configuration of a lighting circuit for a verification experiment. The lighting circuit for the verification experiment includes a lamp lighting circuit 41 connected to the electrodes (12p, 12n) of the flash discharge lamp 10, and a trigger circuit 42 connected to the conductive member 14. A pulse current with a short duration is input to the flash discharge lamp 10 as an energy source for instantaneous discharge. The duration and energy amount of the pulse current can be adjusted by the capacitance of the capacitor 43, the inductance of the coil 44, and the voltage value of the charger 45. Here, a 600 μF capacitor 43 and a coil 44 for adjusting the flash duration to 0.5 ms are used.

[0056] First, the capacitor 43 is charged up to 4000V by the voltage of the charger 45. Next, the trigger circuit 42 is driven, and a trigger voltage of about 10 kV is applied to the conductive member 14. The application of the trigger voltage generates a barrier discharge near the inner wall of the arc tube 11 close to the trigger tube 13, and when a discharge is generated between the pair of electrodes (12p, 12n), the lamp breakdown voltage drops, and when the breakdown voltage becomes equal to or lower than the charging voltage, the flash discharge lamp 10 flashes.

[0057] The life evaluation was carried out by repeating this lighting every minute for about 100,000 times, and the blackening state of the trigger tube 13 was confirmed.

[0058] (result) Table 1 shows the results of comparing the blackening state after the life evaluation. In the table, the blackening cumulative length is the cumulative length of the blackening area that is intermittently distributed in the X direction of the trigger tube 13 in the area facing the pair of electrodes (12p, 12n). The more blackening there is, the longer the blackening area becomes.

[0059] [Table 1]

[0060] As a result, it was found that the blackening cumulative length tends to decrease with an increase in the number of shrunk parts. In particular, in Example 2, which had three shrunk parts, blackening was significantly suppressed compared to the comparative example. In Example 2, blackening was hardly observed in areas other than the shrunk parts. In Example 1, blackening was suppressed compared to the comparative example, but blackening was confirmed in areas other than the two shrunk parts. In the case of two shrunk parts, there is an area where the conductive member 14 comes into contact with the inner surface of the insertion tube 15 due to vibration, and it is presumed that blackening occurred in that area.

[0061] From the above, by providing a plurality of shrink parts, blackening can be suppressed. Moreover, from the viewpoint of suppressing contact of the conductive member 14 with the inner peripheral surface of the insertion tube 15 between the shrink parts, it is preferable that the number of shrink parts is three or more.

[0062] [Verification experiment 2] Based on the results of verification experiment 1, a flash discharge lamp 10 with a further increased number of shrunk portions was evaluated.

[0063] Example 3 Example 3 is similar to Example 2, except that there were four shrunk parts. The intervals between the four shrunk parts were 123 mm. The shrunk part closest to the tip 14b of the conductive member 14 was located 20 mm away from the tip 14b of the conductive member 14.

[0064] Example 4 Example 4 is similar to Example 2, except that there were five shrunk parts. The intervals between the five shrunk parts were 98 mm. The shrunk part closest to the tip 14b of the conductive member 14 was located 20 mm away from the tip 14b of the conductive member 14.

[0065] (result) As a result, in the same manner as in Example 2, in Examples 3 and 4, almost no blackening was observed in areas other than the shrunk portion. In addition, as an index of the blackening density in the shrunk portion, the trigger tube 13 after the life evaluation was destroyed, and the visible light transmittance of the blackened area of ​​the shrunk portion was measured and compared. Since the transmittance of the shrunk portion may differ from that of the material due to the lens effect due to the shape, a relative comparison was made with the transmittance of the shrunk portion of an unused trigger tube 13 set to 100. Table 2 shows the results of comparing the transmittance in the blackened area of ​​the shrunk portion. The values ​​in Table 2 are the average transmittance values ​​obtained in each shrunk portion.

[0066] [Table 2]

[0067] In Examples 3 and 4, the relative transmittance was higher than in Example 2. In other words, it is considered that the more shrunk parts there were, the less blackening occurred per shrunk part, and it is possible to suppress the load due to contact with the conductive member 14 and the light absorption due to blackening. In addition, the transmittance increased as the number of shrunk parts increased, but the rate of increase with respect to the increase in the number of shrunk parts tended to decrease.

[0068] From the above, by providing two or more, preferably three or more, shrink sections in the insertion tube 15, it is possible to provide a trigger tube 13 that is resistant to blackening until the end of lighting even under short pulse flash conditions, and this effect makes it possible to prevent a decrease in illuminance and a deterioration in illuminance distribution on the workpiece undergoing flash annealing.

[0069] Although the embodiments of the present invention have been described above based on the drawings, the specific configuration should not be considered to be limited to these embodiments. The scope of the present invention is indicated not only by the description of the above embodiments but also by the claims, and further includes all modifications within the meaning and scope of the claims.

[0070] The structures employed in the above-described embodiments can be employed in any other embodiment. The specific configurations of the components are not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0071] In the flash discharge lamp 10, the conductive member 14 may be configured to be coated with a metal belonging to the platinum group. Examples of metals belonging to the platinum group include rhodium (Rh), ruthenium (Ru), platinum (Pt), and iridium (Ir).

[0072] Platinum group metals have a relatively high melting point (1700°C or higher) and are highly resistant to oxidation and corrosion. Therefore, platinum group metals barely melt even at the temperature at which the insertion tube 15 softens (for example, about 1000°C to 1700°C for quartz glass, depending on the composition and impurity concentration, etc.). By covering the conductive member 14 with a platinum group metal, the conductive member 14 is protected from contact with oxygen desorbed from the insertion tube 15, so that the insertion tube 15 is less likely to blacken.

[0073] The platinum group metal is formed as a thin film by metal vapor deposition or plating on the outer surface of the conductive member 14. When coated with platinum (Pt), the thickness of the thin film is adjusted to be within a range of 0.03 μm to 3.5 μm, and from the viewpoint of preventing the conductive member 14 from being oxidized, the thickness is preferably 0.03 μm or more and 100 μm or less, and more preferably 0.05 μm or more and 50 μm or less. [Explanation of symbols]

[0074] 1: Flash irradiation device 10: Flash discharge lamp 11: Light emitting tube 12p: Electrode 12n: Electrode 13: Trigger tube 14: Conductive materials 14a: proximal end 14b: Tip 15: Insertion tube 15a: Shrink section 15b: Shrink section 15c: Shrink section 16: Molybdenum foil 17: Pin 20: Reflective material 21: Reflective surface 30: Support stand 30a: pin 41: Lamp lighting circuit 42: Trigger circuit 43: Capacitor 44: Coil 45: Charger D: Distance between a pair of electrodes L1: light W1: Work

Claims

1. an arc tube extending in a first direction and transparent to light; a pair of electrodes disposed opposite each other in the first direction inside the arc tube; a trigger tube disposed along the outside of the light emitting tube and extending between the pair of electrodes; The trigger tube comprises: A conductive member extending along the first direction; an insertion tube that is transparent to light and extends along the first direction and has at least a portion of the conductive member housed therein; In the flash discharge lamp, the insertion tube has a plurality of shrink portions along the first direction in a region facing the pair of electrodes, the shrink portions having parts of their inner surfaces that protrude toward the conductive member.

2. the conductive member has a base end supported on one end of the insertion tube and a tip end not in contact with the other end of the insertion tube, 2. The flash discharge lamp according to claim 1, wherein the shrink portion closest to the tip among the plurality of shrink portions is closer to the tip than to a center between the pair of electrodes.

3. 2. The flash discharge lamp according to claim 1, wherein when the distance between the pair of electrodes is D, the number of the shrunk portions is N (N is a natural number equal to or greater than 2), and the maximum spacing among the plurality of shrunk portions is Amax, a relationship of Amax≦D / N is satisfied.

4. The flash discharge lamp according to claim 1 , wherein the insertion tube includes three or more of the shrink portions.

5. 2. The flash discharge lamp according to claim 1, wherein the conductive member is made of tungsten or molybdenum.

6. 2. The flash discharge lamp of claim 1, wherein the conductive member is coated with a metal belonging to the platinum group.

7. A flashlight lighting device comprising the flashlight discharge lamp according to any one of claims 1 to 6.

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