Flash lamp

Abstract

To provide a flash lamp that can obtain a stable light output and prevent a decrease in luminous intensity due to the accumulation of the number of discharges.SOLUTION: A flash lamp 1 according to the present invention includes a lamp housing 2 filled with an inert gas and sealed, a cathode 20 and an anode 30 for generating an arc discharge, a trigger electrode 40 for performing a preliminary discharge prior to the arc discharge, and a plurality of sparkers 60, 70 for promoting ionization for starting the arc discharge, the plurality of sparkers 60, 70 are spaced apart from each other. At least one of the plurality of sparkers can be disposed near the cathode 20. Furthermore, a plurality of trigger electrodes 40 can be provided.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a flash lamp.

Background Art

[0002] In recent years, a flash lamp that uses xenon gas in particular as an inert gas to be enclosed has been utilized as a light source for spectroscopic analysis because a strong emission spectrum over a wide band from ultraviolet to infrared can be obtained. Its applications include water quality inspection devices, automotive exhaust gas monitors, nitrogen oxide monitors, and the like. Since the emission is obtained by arc discharge due to the discharge of a charged capacitor, it has a high light output, low heat generation, and long life compared to light sources such as deuterium lamps, and the factors of energy saving and maintenance-free are important for its reuse as a light source.

[0003] However, conventional flash lamps have drawbacks such as a flash miss phenomenon where light emission does not occur, or the light emission intensity fluctuates for each emission, or the absolute value of the light emission intensity decreases due to the accumulation of the number of discharges, and improvements have been attempted in various ways. As an example, when a metal material containing a large amount of barium on a tungsten substrate is used as the cathode material to lower the work function so that electrons can be easily emitted, the electrode is severely consumed and has a short life. In addition, the glass faceplate through which the emitted light passes becomes cloudy due to sputtering accompanying arc discharge, and the light emission intensity decreases due to the accumulation of the number of discharges.

[0004] As a solution, an attempt can be made to reduce the amount of barium to reduce sputtering. However, even when the arc discharge space distance between the cathode and the anode is short, a phenomenon occurs where arc discharge does not start and light emission does not occur at the initial stage due to the accumulation of the number of discharges. Therefore, a means is taken to supplement the difficulty of discharging from the electrodes by providing a plurality of trigger electrodes. However, even with this method, a flash miss phenomenon may occur where arc discharge does not start and light emission does not occur. On the other hand, even if this phenomenon is avoided, a phenomenon occurs where the arc discharge path is slightly different for each discharge. In an optical system that uses the emitted light of a flash lamp through a narrow slit, the amount of light passing through the slit apparently fluctuates, increasing the number of aperture jitters, and thus a fundamental solution has not been achieved.

[0005] Patent Document 1 describes a technique for reducing the variation in the discharge path for each pulse emission and improving the light output stability. A cathode and an anode for performing arc discharge are arranged opposite each other in a lamp housing filled with an inert gas, and a plurality of needle-shaped trigger electrodes for performing preliminary discharge prior to arc discharge are arranged between the cathode and the anode.

[0006] Patent Document 2 describes a technique for reducing the labor, cost, and variation in work related to a flash lamp and an attached sparker. The sparker is directly incorporated into the sealed through-connection header of the flash lamp.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] The flash lamps of Patent Documents 1 and 2 have improved light output stability. However, a xenon flash lamp is desired that further suppresses fluctuations in emission intensity for each emission as much as possible and eliminates the characteristic that the absolute value of the emission intensity decreases due to the accumulation of the number of discharges.

[0009] Also, even in a flash lamp with a long arc discharge distance between the cathode and the anode, a xenon flash lamp having the above characteristics is desired. Further, a xenon flash lamp is desired that reduces the number of leads implanted and led out from the flash lamp, secures the creepage distance between pads when connecting the flash lamp to the pattern of the printed circuit board to make creeping discharge difficult, and can lower the temperature rise of the cathode.

[0010] In view of the above problems, an object of the present invention is to provide a flash lamp capable of obtaining a stable light output and preventing the emission intensity from decreasing due to the accumulation of the number of discharges.

Means for Solving the Problems

[0011] To solve the above problems, the invention according to claim 1 includes a lamp housing filled with and sealed with an inert gas, a cathode and an anode that generate an arc discharge, a trigger electrode that performs a preliminary discharge prior to the arc discharge, and a plurality of sparkers that promote ionization for starting the arc discharge. The plurality of sparkers are arranged separately from each other, and it is a flash lamp characterized by this. According to the invention of claim 1, in the flash lamp, a cathode, an anode that generate an arc discharge, and a trigger electrode that performs a preliminary discharge prior to the arc discharge are arranged in a lamp housing filled with an inert gas, and a plurality of sparkers that promote ionization for starting the arc discharge are provided separately from each other. Therefore, it is possible to expand the ionization region by ultraviolet rays generated when the sparkers emit light, and it is possible to facilitate the emission of electrons from the cathode, anode, or trigger electrode into the plasma. The invention according to claim 2 is the flash lamp according to claim 1, characterized in that at least one of the plurality of sparkers is arranged in the vicinity of the cathode. According to the invention of claim 2, in addition to the configuration of the invention of claim 1, at least one of a plurality of sparkers that promote ionization for arc discharge start is arranged in the vicinity, so that the emission of electrons from the cathode, which is the starting point of light emission, into the plasma is more easily, surely, and stably performed. The invention according to claim 3 is the flash lamp according to claim 1, characterized by comprising a plurality of the trigger electrodes. According to the invention of claim 3, in addition to the configuration of the invention of claim 1, a plurality of trigger electrodes are arranged such that the tip of each trigger electrode is located on a line connecting the small spherical surface portions of the end faces facing the cathode and the anode in the vicinity of the arc discharge path between the cathode and the anode. Therefore, stable light emission can be obtained even when the arc discharge distance between the cathode and the anode is long. The invention according to claim 4 is the flash lamp according to claim 1, characterized in that the cathode, the anode, the trigger electrodes, and the plurality of sparkers are arranged on a stem inside the lamp housing, and leads for supplying electricity to each of the anode, the trigger electrodes, and the plurality of sparkers are electrically insulated from the stem and planted and led out to the outer surface of the lamp housing. The stem includes a metal exhaust pipe, and the exhaust pipe is connected to the cathode to serve as a power supply terminal. According to the invention of claim 4, since the metal exhaust pipe is connected to the cathode inside the lamp housing, the lead for the negative electrode can be eliminated, and the flash lamp can be miniaturized by reducing the number of leads. In addition, when connecting to the pattern of the printed circuit board, the creepage distance between the patterns for attaching each lead can be increased, so that the printed circuit board can also be miniaturized. Furthermore, since the heat generated by the cathode during light emission can be dissipated by the metal exhaust pipe, the temperature rise of the flash lamp can be reduced, and the amount of sputtering associated with arc discharge can be decreased. The invention according to claim 5 is such that the cathode, the anode, the trigger electrode, and the plurality of sparkers are arranged on a stem within the lamp housing, leads for supplying electricity to each of the cathode, the trigger electrode, and the plurality of sparkers are planted in electrical insulation from the stem and led out to the outer surface of the lamp housing, the stem includes an exhaust pipe made of metal, and the exhaust pipe is connected to the anode and serves as a power supply terminal, which is the flash lamp according to claim 1. The invention according to claim 5 also achieves the same effects as those of claim 4. The invention according to claim 6 includes a lamp housing filled and sealed with an inert gas, a cathode and an anode for generating an arc discharge, a trigger electrode for performing a preliminary discharge prior to the arc discharge, and a sparker for promoting ionization for starting the arc discharge. The cathode, the anode, the trigger electrode, and the sparker are arranged on a stem within the lamp housing. Leads for supplying electricity to each of the anode, the trigger electrode, and the sparker are planted in electrical insulation from the stem and led out to the outer surface of the lamp housing. The stem includes an exhaust pipe made of metal, and the exhaust pipe is connected to the cathode and serves as a power supply terminal, which is a flash lamp. According to the invention of claim 6, in addition to the same effects as those of the inventions of claims 4 and 5, when there is one sparker, it is possible to further simplify and miniaturize the flash lamp. The invention according to claim 7 includes a lamp housing filled and sealed with an inert gas, a cathode and an anode for generating an arc discharge, a trigger electrode for performing a preliminary discharge prior to the arc discharge, and a sparker for promoting ionization for starting the arc discharge. The cathode, the anode, the trigger electrode, and the sparker are arranged on a stem within the lamp housing. Leads for supplying electricity to each of the cathode, the trigger electrode, and the sparker are planted in electrical insulation from the stem and led out to the outer surface of the lamp housing. The stem includes an exhaust pipe made of metal, and the exhaust pipe is connected to the anode and serves as a power supply terminal, which is a flash lamp. The invention according to claim 7 can also achieve the same effects as those of claim 6.

Advantages of the Invention

[0012] The flash lamp of the present invention can obtain a stable light output and prevent the light emission intensity from decreasing due to the accumulation of the number of discharges.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Mode for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention (hereinafter abbreviated as examples) will be described with reference to the drawings. In the following drawings, the same reference numerals are given to common parts, and redundant explanations for the parts with the same reference numerals are omitted. In the following examples, an example including two sparkers (a first sparker 60 and a second sparker 70) as a plurality of sparkers will be described, but the present invention is not limited to this and can be applied to a flash lamp including three or more sparkers.

Example

[0015] The configuration of the flash lamp 1 of this example will be described with reference to FIGS. 1 to 8. As shown in FIG. 1, the flash lamp 1 includes a lamp housing in which an inert gas is enclosed and sealed, a cathode 20 and an anode 30 that generate an arc discharge, a trigger electrode 40 that performs a preliminary discharge prior to the arc discharge, and a plurality of sparkers (a first sparker 60 and a second sparker 70) that promote ionization for starting the arc discharge. The first sparker 60 and the second sparker 70 are arranged so as to be separated from each other so that when discharging respectively, the discharges of the sparkers do not mix or interfere with each other and spark. As the inert gas to be enclosed, for example, xenon gas is used.

[0016] The cathode 20 and the anode 30 are shaped like a substantially conical surface with a spherical tip at the end so that their opposing end faces cause arc discharge to occur through a stable path. The other ends of the cathode 20 and the anode 30 are press-fitted with lead rods 21 and 31 made of molybdenum or the like, and each electrode is fixed to leads 22 and 32 by spot welding or the like. The cathode 20 and the anode 30 use materials with a small work function as the electron-emitting material. For example, they contain barium oxide, aluminum oxide, calcium oxide, etc. with tungsten as the base material.

[0017] As shown in FIGS. 2 and 3, the lead 32 electrically connected to the anode 30 is implanted so as to penetrate a disk-shaped stem 3 made of metal through an insulator 33 made of glass and formed in a hemispherical shape to ensure a long creepage distance. Although the cathode 20 can be configured in the same way as the anode 30, in this embodiment, the lead 22 electrically connected to the cathode 20 is welded and fixed to the surface of the metal stem 3.

[0018] The lamp housing 2 is composed of a stem 3, a metal cap 4, and a transmissive glass 5. One end of the cap 4 is fitted into the outer circumferential portion of the metal stem 3, and the mating portion is sealed by welding. On the other hand, the other end of the cap 4 has a transmissive glass 5 made of a material such as quartz glass or borosilicate glass welded inside the flange portion to transmit the arc discharge light from the cathode 20 and the anode 30.

[0019] A metal exhaust pipe 6 is welded to the central part of the stem 3. An inert gas such as xenon gas is injected through the exhaust pipe 6, and then the exhaust pipe 6 is sealed, whereby the lamp housing 2 is sealed. As described above, in this embodiment, since the lead 22 connected to the cathode 20 is welded and fixed to the surface of the stem 3, the exhaust pipe 3 led out to the outside of the lamp housing 2 can be electrically connected as a heat dissipation path of the cathode 20. That is, the exhaust pipe 3 can be used as a terminal for connecting to the cathode 20 and supplying power. In this embodiment, such a configuration is adopted. Note that the electrical connection of the cathode 20 is not limited to this embodiment, and it can also be configured in the same manner as the anode 30. Also, the exhaust pipe 3 can be used as a terminal for connecting to the anode 30 and supplying power. In that case, the lead 22 electrically connected to the cathode 20 is planted so as to penetrate the metal disk-shaped stem 3 through an insulator made of glass and having a hemispherical shape and ensuring a long creepage distance (not shown).

[0020] The trigger electrode 40 is made of a tungsten material or the like. As shown in FIG. 3, the tip of the trigger electrode 40 is arranged slightly closer to the cathode 20 on a substantially straight line connecting the small spherical surface portion of the end face where the cathode 20 and the anode 30 face each other. A lead 42 fixed to the trigger electrode 40 by spot welding or the like is planted so as to penetrate the stem 3 through a glass insulator 43 in the same manner as the anode 30 and is led out to the outside of the lamp housing 2. Note that the leads 22, 32, 42, 62, 72, the stem 3, the cap 4, and the exhaust pipe 6 are made of metal in this embodiment, and for example, kovar metal is used. Note that in this embodiment, the stem 3, the cap 4, and the exhaust pipe 6 are made of metal, but the material is not limited to metal and may be glass or the like.

[0021] As shown in the cross-sectional views of FIGS. 4 and 5, the first sparker 60 has a structure in which a tubular insulator 64 made of alumina or the like having sufficient tracking resistance surrounds a sparker pin 61 made of a tungsten material or the like, and the periphery thereof is surrounded by a nickel plate 65 serving as a cathode. The nickel plate 65 is welded and fixed to the stem 3. One end of the sparker pin 61 is drawn out to the outside of the lamp housing 2 through a lead 62 implanted so as to penetrate the stem 3 via a glassy insulator 63. The other end of the sparker pin 61 has the end faces of the sparker pin 61, the insulator 64, and the nickel plate 65 arranged substantially flush as shown in FIG. 4, and surface discharge or space discharge occurs between the sparker pin 61 and the nickel plate 65. The second sparker 70 is also composed of a glassy insulator 73, a tubular insulator 74 made of alumina or the like, a nickel plate 75, a lead 72, and a sparker pin 71, similar to the first sparker 60.

[0022] As shown in FIGS. 1 and 3, in this embodiment, the first sparker 60 and the second sparker 70 are arranged near the cathode 20. The arrangement of the first sparker 60 and the second sparker 70 is not limited to the arrangement in FIG. 3. Only one of them may be arranged near the cathode 20, or neither of them needs to be arranged near the cathode 20. Also, as described above, the first sparker 60 and the second sparker 70 are arranged separately. If they are arranged close to each other, a problem phenomenon in which the discharges of each interfere with each other will occur, so it is preferable to avoid extreme proximity. Further, when the first sparker 60 and the second sparker 70 are arranged extremely close to the cathode 20 or the anode 30, the same problem phenomenon will occur, so they are arranged at a distance where space discharge does not occur.

[0023] In the flash lamp 1 configured as described above, a main discharge capacitor (107 in FIG. 14) connected in parallel between the cathode 20 and the anode 30 that generates arc discharge is charged to about 300V to 1000V with the cathode 20 at a negative potential and the anode 30 side at a positive potential. With the cathode 20 as the reference potential, a steep spike voltage of about 4000V negative potential is applied between the cathode 20 and the spark pin 61 of the first sparker 60, the spark pin 71 of the second sparker 70, the trigger electrode 40, and the anode 30.

[0024] When the spike voltage value reaches about 500V to 2500V, several hundred nanoseconds after the steep spike voltage starts rising towards about 4000V, pre-discharge starts at different spike voltage values between the cathode 20 and the trigger electrode 40, between the nickel plate 65 electrically connected to the cathode 20 and the spark pin 61, and further between the nickel plate 75 and the spark pin 71, and ionization for starting arc discharge progresses. Then, after about 1 microsecond, the space filled with the inert gas between the cathode 20 and the anode 30 breaks and arc discharge occurs and emits light.

[0025] In this embodiment, since the first sparker 60 and the second sparker 70 that perform pre-discharge prior to arc discharge are arranged near the cathode 20, ionization for starting arc discharge is performed evenly over a wide range. Accordingly, the emission of electrons into the plasma atmosphere from the cathode 20 towards the anode 30 becomes easier, and for example, it is possible to surely avoid a malfunction phenomenon where arc discharge does not occur even when a steep spike voltage is applied. Also, since the cathode 20 or the anode 30 is formed of a conductive material with a high tungsten ratio, although the electron emission is at a normal level, the electrode consumption is small, so a stable light output can be obtained and it is possible to prevent the light emission intensity from decreasing due to the accumulation of the number of discharges.

[0026] Furthermore, comparing the prior art that uses a plurality of trigger electrodes 40 to perform a preliminary discharge prior to the arc discharge with the present invention, in the prior art, since the tips of the plurality of trigger electrodes 40 are arranged in the vicinity of the arc discharge path between the cathode 20 and the anode 30, when the slit width of the optical system is short, there is a drawback that the shadow of the trigger electrode 40 may be reflected in the slit depending on the arc discharge path. On the other hand, due to the structure of the discharges of the first sparker 60 and the second sparker 70 in this embodiment, the discharge path is self - contained because the discharge occurs between the lead 62 and the nickel plate 65 in the first sparker 60 and between the lead 72 and the nickel plate 75 in the second sparker 70. Therefore, the installation locations of the first sparker 60 and the second sparker 70 have a high degree of freedom and do not have to be installed on or near the arc discharge path between the cathode 20 and the anode 30, so the above - mentioned drawbacks are not caused. This also applies when three or more sparkers are provided.

[0027] Also, in this embodiment, since the metal exhaust pipe 6 welded to the center of the stem 3 is used as a terminal for supplying power to the cathode 20 led out to the outside of the flash lamp 1, the number of leads led out from the flash lamp 1 can be reduced, and the projected area of the flash lamp 1 can be made smaller. Thereby, when connecting the leads of the flash lamp 1 to the patterns on the printed circuit board, the creepage distance between the patterns for attaching the respective leads can be increased, so the creepage discharge start voltage between the patterns on the printed circuit board becomes higher, and the insulation treatment on the surface of the printed circuit board can be made unnecessary or simplified. Furthermore, since the heat generated by the cathode during light emission can be dissipated by the metal exhaust pipe, the temperature rise of the flash lamp 1 can be reduced, and thus the amount of sputtering associated with arc discharge can be decreased. Using the metal exhaust pipe 6 as a terminal for supplying power to the cathode 20 in this way is particularly useful for flash lamps with a small outer diameter of the lamp housing 1. The same effect can be obtained when the metal exhaust pipe 6 is used as a terminal for supplying power to the anode 30 led out to the outside of the flash lamp 1. Also, even when there is one sparker, the metal exhaust pipe 6 can be used as a terminal for supplying power to the cathode 20 or the anode 30 led out to the outside of the flash lamp 1, and in that case, the flash lamp can be made simpler and smaller.

[0028] Next, several embodiments having an arrangement different from the arrangement shown in FIG. 3 will be described. FIGS. 6 to 8 are plan views showing the cathode 20, anode 30, trigger electrode 40, first sparker 60, and second sparker 70 having an arrangement different from that of FIG. 3. In the embodiment shown in FIG. 6, the first sparker 60 is arranged near the cathode 20, and the second sparker 70 is arranged near the anode 30, and both are arranged on the trigger electrode 40 side. This arrangement also provides the same effect as the previous embodiment (the arrangement of FIG. 3).

[0029] In the embodiment shown in FIG. 7, the first sparker 60 is disposed near the cathode 20, and the second sparker 70 is disposed near the anode 30, both being disposed on the side facing the trigger electrode 40. Thereby, in addition to the effects of the previous embodiment, the assembly of the electrodes becomes easy, and the insulation within the lamp housing 2 or between each of the leads 32, 42, 62, 72 becomes easy.

[0030] In the embodiment shown in FIG. 8, the first sparker 60 is disposed near the cathode 20, and the second sparker 70 is disposed near the anode 30. The first sparker 60 is disposed on the side of the trigger electrode 40, and the second sparker 70 is disposed on the side facing the trigger electrode 40. Thereby, in addition to the effects of the previous embodiment, since the first sparker 60 and the second sparker 70 are installed at positions separated from each other, their assembly becomes easy, and the assemblability of the entire flash lamp 1 is improved.

Embodiment

[0031] FIGS. 9 and 10 are plan views showing the arrangement of the cathode 20, anode 30, trigger electrode 40, trigger electrode 50, first sparker 60, and second sparker 70 of the flash lamp 100, which is the second embodiment, with the transmissive glass and the cap removed. The configurations of the lamp housing 2, cathode 20, anode 30, trigger electrode 40, trigger electrode 50, first sparker 60, second sparker 70, etc. constituting the flash lamp 100 are the same as those of the first embodiment, and thus the description thereof is omitted. The difference between the second embodiment and the first embodiment is that a plurality of trigger electrodes are provided. The embodiments of FIGS. 9 and 10 illustrate a flash lamp 100 in which the distance (inter-pole) between the tips of the cathode 20 and the anode 30 is wider than that of the first embodiment. In the case of such a flash lamp 100 with a wide inter-pole, arc discharge can be facilitated by providing two trigger electrodes. The embodiments of FIGS. 9 and 10 have two trigger electrodes, but may be configured to have three or more trigger electrodes. The two trigger electrodes of this embodiment are referred to as a first trigger electrode 40 (the trigger electrode 40 in FIGS. 3 to 8) and a second trigger electrode 50, respectively.

[0032] In the embodiment shown in Fig. 9, the second trigger electrode 50 has the same configuration and structure as the first trigger electrode 40, and its tip is arranged to be located on a substantially straight line connecting the small spherical portions of the opposing end faces of the cathode 20 and the anode 30. Similar to the first trigger electrode 40, a lead 52 fixed to the second trigger electrode 50 by spot welding or the like is implanted so as to penetrate the stem 3 through a glassy insulator 53 and drawn out to the outside of the lamp housing 2. By arranging the tips of the first trigger electrode 40 and the second trigger electrode 50 in the vicinity of the arc discharge path between the cathode 20 and the anode 30, it is possible to obtain stable light emission even when the arc discharge distance between the cathode 20 and the anode 30 is long. In the embodiment shown in Fig. 9, an example is shown in which the first sparker 60 is arranged near the cathode 20 and the second sparker 70 is arranged near the anode 30. Also in the second embodiment, the effect of providing two sparkers is the same as that of the first embodiment.

[0033] The embodiment shown in Fig. 10 has the same configuration as the embodiment of Fig. 9 in which a new second trigger electrode 50 is provided. However, mainly by devising the arrangement of the first trigger electrode 40 and the second trigger electrode 50, the shapes of the implanted leads 42 and 52 remain substantially linear, and the tip portions of the first trigger electrode 40 and the second trigger electrode 50 are assembled so as to be located on a substantially straight line connecting the small spherical portions of the opposing end faces of the cathode 20 and the anode 30. As shown in Fig. 10, in this embodiment, the first sparker 60 and the second sparker 70 are provided near the cathode 20 and at positions facing each other with the cathode 20 interposed therebetween. The flash lamp 100 of this embodiment can also obtain the same effect as the embodiment shown in Fig. 9, and in addition, the assembly is easy.

Embodiment

[0034] FIG. 11 is a partially cut-away perspective view of a flash lamp 200 according to a third embodiment of the present invention. FIG. 12 is a rear view of the flash lamp 200 with the transmissive glass and the cap removed, and FIG. 13 is a plan view showing the arrangement of the cathode 20, the anode 30, the trigger electrode 40, the first sparker 60, and the second sparker 70 with the transmissive glass and the cap of the flash lamp 200 removed. The difference between the third embodiment and the first embodiment is that the stem 3 and the cap 4 are made of a glass material instead of a metal such as kovar. Accordingly, the lead 22 welded to the cathode 20 is implanted and penetrated into the stem 3, and the nickel plates 65 and 75 of the first sparker 60 and the second sparker 70 are electrically connected to the lead 22 of the cathode 20. Since the other configurations are the same as those of the first embodiment, the description thereof is omitted.

[0035] When the stem 3 and the cap 4 are made of a glass material, it is possible to avoid the lead bars 21 and 31 of the cathode 20 and the anode 30, the trigger electrode 40, etc. from approaching the stem 3 or the cap 4 and discharging with them, which is effective when the flash lamp 200 has a small diameter.

[0036] Also in the third embodiment, the effect of providing two sparkers is the same as that of the first embodiment. Note that the material of the exhaust pipe 6 can achieve the effects of the present invention whether it is metal or glass. Also, Even when the arc discharge distance between the cathode 20 and the anode 30 is long, by arranging two trigger electrodes in the same manner as in the second embodiment, stable light emission can be obtained.

[0037] Next, the block circuit diagrams of the lighting devices for lighting the flash lamps of the first to third embodiments will be described with reference to FIGS. 14 and 15. FIG. 14 is a block circuit diagram of a lighting device for lighting the flash lamp of the first embodiment or the third embodiment. FIG. 15 is a partial block circuit diagram of a lighting device for lighting the flash lamp of the second embodiment.

[0038] First, the configuration of the block circuit diagram in FIG. 14 will be described. Terminal A is a power input terminal, and terminal B is the GND terminal of power supply terminal A. DC power is supplied through these terminals. The range of the supply voltage is usually from the 3.3V system used in USB to the 24V system used in FA control. Terminal C is a pulse voltage signal input terminal for lighting the flash lamp 1.

[0039] One end of the primary winding of the flyback transformer 102 is connected to terminal A, and the other end is connected to the drain of the MOSFET 111. The source of the MOSFET 111 is connected to terminal B. By the ON / OFF switching of the MOSFET 111, the main discharge capacitor 107 is charged to a predetermined voltage between 300V and 1000V in this case from the secondary winding of the flyback transformer 102 through the reverse blocking diode 103. Both ends of the main discharge capacitor 107 are connected to the anode 30 and the cathode 20 of the flash lamp 1 to form an arc discharge circuit.

[0040] From the intermediate winding part of the secondary winding of the flyback transformer 102, a charging circuit for the pulse generation capacitor 109 is formed on the primary side of the trigger transformer 110 through the reverse blocking diode 104 and a regulator 106 is provided in the middle to make the charging voltage of the pulse generation capacitor 109 constant at a certain point between about 100V and 200V. The IGBT 108 discharges the charging charge of the pulse generation capacitor to the primary side of the trigger transformer 110.

[0041] A high-voltage pulse voltage of about 4000V is output from the secondary winding of the trigger transformer 110. The DC blocking capacitors 81 - 84 have one end connected to the secondary winding of the trigger transformer 110, and the other end is connected to the anode 30 of the flash lamp 1, the trigger electrode 40, the first sparker 60, and the second sparker 70 as shown in FIG. 14, respectively. High-resistance discharge resistors 91 - 94 are connected in parallel to the capacitors 81 - 84, respectively.

[0042] In the partial block circuit diagram of FIG. 15, the parts having the same functions as those in FIG. 14 are assigned the same numbers. In the partial block circuit diagram of FIG. 15, a DC-blocking capacitor 85 and high-resistance discharge resistors 95 and 96 are added for the second trigger electrode 50 for the same purpose as described above.

[0043] The inputs of the controller 101 are connected and powered such that the P terminal is connected to the A terminal and the G terminal is connected to the B terminal. The IN2 terminal inputs with reference to the charging voltage of the main discharge capacitor 107. The outputs of the controller 101 are connected such that the 01 terminal is connected to the gate of the MOSFET 111 and the 02 terminal is connected to the base of the IGBT 108. The IN1 terminal is a terminal for inputting a pulsed trigger signal for causing the flash lamp 1 connected to the C terminal to emit light. The controller 101 is configured to emit light once in response to one input of the trigger signal.

[0044] Next, the operations of FIGS. 14 and 15 will be described. Until immediately before a pulsed trigger signal is input from the IN1 terminal to the controller 101, the controller 101 outputs a pulse-width control signal from the 01 terminal to the MOSFET 111 so as to match a target charging voltage that becomes a predetermined value with reference to the charging voltage of the main discharge capacitor 107 from the IN2 terminal.

[0045] When the primary winding of the flyback transformer 102 is excited by the ON control of the MOSFET 111 and the excitation of the primary winding stops due to the OFF control of the MOSFET 111, the main discharge capacitors 107 and 109 are charged from the secondary winding through the diodes 103 and 104 by the magnetic energy stored in the flyback transformer 102.

[0046] When a trigger signal is input from the IN1 terminal while the main discharge capacitor 107 and the pulse generation capacitor 109 are charged to a predetermined voltage, the controller 101 stops the output of the pulse width control signal from the 01 terminal for about 500 microseconds in this case. Thus, the charging of the main discharge capacitor 107 and the pulse generation capacitor 109 stops for 500 microseconds. On the other hand, simultaneously with this operation, a pulse signal of about 20 microseconds in this case is output from the 02 terminal to the IGBT 108. Then, the IGBT 108 turns on, and the primary winding of the trigger transformer 110 is excited by the charging charge of the pulse generation capacitor 109. From its secondary winding, a high-voltage and steep negative spike voltage of about 4000 V is applied to the capacitors 81 to 84. In FIG. 15, it is further applied to the capacitor 85 as well.

[0047] Due to the application of this spike voltage, with the cathode 20 as the reference potential, simultaneously, between the cathode 20 and the spark pin 61 of the first sparker 60, between the spark pin 71 of the second sparker 70, between the trigger electrodes 40, between the anodes 30, and in FIG. 15, further between the second trigger electrodes 50 as well, a spike voltage appears and a pre-discharge is started. Therefore, an arc discharge occurs between the anode 30 and the cathode 20 by the above-described mechanism of action, and the flash lamp 1 emits light for several microseconds.

[0048] During the elapse of 500 microseconds, the inert gas inside the flash lamp 1 returns from the ionic state during light emission to the original inert state. After that, when the output of the pulse width control signal from the 01 terminal to the MOSFET 111 is resumed by the controller 101, the pulse width control signal is output from the 01 terminal to the MOSFET 111 so as to match a target charging voltage that becomes a predetermined value while referring to the charging voltage of the main discharge capacitor 107 from the IN2 terminal. Then, the main discharge capacitor 107 and the pulse generation capacitor 109 are charged to a predetermined voltage in several milliseconds, and an operation is performed in preparation for the next light emission operation of the flash lamp 1.

[0049] After that, when a trigger signal is input from the IN1 terminal, the flash lamp 1 emits light in the same operation sequence as described above. Then, the operation of charging the main discharge capacitor 107 and the capacitor 109 for generating a pulse to a predetermined voltage in several milliseconds is repeated.

[0050] As described above, since the flash lamp of the present invention and its circuit are configured, the flash lamp of the present invention can obtain a stable light output and prevent the light emission intensity from decreasing due to the accumulation of the number of discharges. Note that the flash lamp of the above-described embodiment is an example and is not intended to limit the scope of the invention. It can be implemented in various other forms and can be appropriately changed without departing from the spirit of the invention.

Explanation of Reference Numerals

[0051] 1, 100, 200... flash lamp, 2... lamp housing, 3... stem, 4... cap, 5... transmissive glass, 6... exhaust pipe, 20... cathode, 21, 31... lead bar, 22, 32, 42, 52, 62, 72... lead, 23, 33, 43, 53, 63, 73... insulator, 30... anode, 40... (first) trigger electrode, 50... second trigger electrode, 60... first sparker, 61, 71... sparker pin, 64, 74... insulator, 65, 75... nickel plate, 70... second sparker, 81 - 85... capacitor, 91 - 96... resistor, 101... controller , 102... flyback transformer, 103 - 105... diode, 106... regulator, 107... main discharge capacitor, 108... IGBT, 109... trigger capacitor, 110... trigger transformer, 111... MOSFET, A... power supply terminal (plus), B... power supply terminal (minus), C... pulse voltage signal input terminal.

Claims

1. A lamp housing filled with and sealed with an inert gas, a cathode and an anode that generate an arc discharge, a trigger electrode that performs a preliminary discharge prior to the arc discharge, a plurality of sparkers that promote ionization for starting the arc discharge, and the plurality of sparkers are arranged separately from each other, a flash lamp characterized in that.

2. The flash lamp according to claim 1, wherein at least one of the plurality of sparkers is arranged near the cathode.

3. The flash lamp according to claim 1, characterized in that a plurality of the trigger electrodes are provided.

4. The cathode, the anode, the trigger electrode, and the plurality of sparkers are arranged on a stem in the lamp housing, and leads for supplying electricity to each of the anode, the trigger electrode, and the plurality of sparkers are electrically insulated from the stem and implanted and led out to the outer surface of the lamp housing. The stem includes a metal exhaust pipe, and the exhaust pipe is connected to the cathode and used as a power supply terminal. The flash lamp according to claim 1, characterized in that.

5. The cathode, the anode, the trigger electrode, and the plurality of sparkers are arranged on a stem in the lamp housing, and leads for supplying electricity to each of the cathode, the trigger electrode, and the plurality of sparkers are electrically insulated from the stem and implanted and led out to the outer surface of the lamp housing. The stem includes a metal exhaust pipe, and the exhaust pipe is connected to the anode and used as a power supply terminal. The flash lamp according to claim 1, characterized in that.

6. A lamp housing filled with and sealed with an inert gas, a cathode and an anode that generate an arc discharge, a trigger electrode that performs a preliminary discharge prior to the arc discharge, and a sparker that promotes ionization for starting the arc discharge, and the cathode, the anode, the trigger electrode, and the sparker are arranged on a stem in the lamp housing, and leads for supplying electricity to each of the anode, the trigger electrode, and the sparker are electrically insulated from the stem and implanted and led out to the outer surface of the lamp housing. The stem includes a metal exhaust pipe, and the exhaust pipe is connected to the cathode and used as a power supply terminal. A flash lamp characterized in that.

7. A lamp housing filled with and sealed with an inert gas, A cathode and an anode that generate an arc discharge, A trigger electrode that performs a preliminary discharge prior to the arc discharge, A sparker that promotes ionization for starting the arc discharge, and are provided, The cathode, the anode, the trigger electrode, and the sparker are disposed on a stem within the lamp housing, and leads for supplying electricity to each of the cathode, the trigger electrode, and the sparker are planted being electrically insulated from the stem and led out to the outer surface of the lamp housing, the stem includes an exhaust pipe made of metal, and the exhaust pipe is connected to the anode to serve as a power supply terminal. A flash lamp characterized by that.

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