JP2016171044A - Flash discharge tube and light irradiation device having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive flash discharge tube that is excellent in light-emission lifetime durability to light emission and durability characteristic to short-time repetitive light emission, and a light irradiation device having the flash discharge tube as a light source.SOLUTION: A flash discharge tube is configured so that a pair of discharge electrodes are air-tightly sealed at both the ends of a light-transmissible envelope while xenon gas is filled in the envelope. A portion of the envelope which surrounds an arc discharge area between the pair of discharge electrodes to form an arc discharge space is formed of aluminosilicate glass which contains aluminosilicate as a main component and little alkali component.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flash discharge tube and a light irradiation apparatus including the flash discharge tube.

  Conventionally, a flash discharge tube has been useful as a light source of a strobe device, which is an artificial light source for illuminating a subject when taking a photo, for example, which is well-known as a light irradiation device. The digitization using electro-optical elements such as CCDs as so-called photosensitive materials for forming subject images has progressed, and this has led to a dramatic increase in the number of shots taken. There is a strong demand for significant improvements.

  By the way, in order to improve the light emission lifetime durability characteristics of a strobe device which is one of the light irradiation devices, it is essential to improve the durability characteristics of the flash discharge tube to which the flash light is emitted. Needless to say, it is necessary to reinforce each constituent material of the flash discharge tube having such a configuration. That is, when looking at the configuration of the flash discharge tube, a pair of discharge electrodes are hermetically sealed at both ends of the glass tube constituting the envelope of the flash discharge tube with xenon gas sealed inside. It has been well known to have such a structure, and there has been a strong demand for strengthening the constituent materials such as the glass tube.

  The pair of discharge electrodes is usually composed of a cathode composed of an electrode pin and a sintered body and an anode formed by the electrode pin itself. Further, as the material of the electrode pin, the light emission of the flash discharge tube is an arc. Since it is a discharge phenomenon and a large current is generated instantaneously, it is necessary to select a material that can withstand such a large current. Conventionally, it has a melting point of about 3400 degrees and is relatively easy to process into an electrode pin state. The use of tungsten, which is a melting point metal, has been common.

  In addition, as the glass tube constituting the envelope of the flash discharge tube, since the hermetically sealing operation with the electrode pin is performed by a heating process, conventionally, the thermal expansion coefficient is approximated to that of tungsten. It has been common to use borosilicate glass tubes designed to lower the softening point and lower the working temperature in the heating process. It is well known that the glass design for lowering the softening point in the borosilicate glass tube is realized by appropriately containing an alkali oxide such as sodium oxide or potassium oxide, which is an alkali component. Silicate glass tubes are recognized in the glass field as glass containing an alkali component.

  On the other hand, when looking at the end-of-life phenomenon in the emission life durability characteristics of the flash discharge tube having the borosilicate glass tube structure as described above, several end-of-life states are known.

  One is the progress of glass tube cracking caused by the application of thermal shock to the glass tube itself by arc discharge, which is a phenomenon that occurs only in the envelope of the flash discharge tube, or by melting and scattering of the discharge electrode to the inner surface of the glass tube. One is the deterioration of the light transmission function of the glass tube due to the evaporation and deposition of the previous alkali component on the inner surface of the glass tube due to the previous thermal shock application and the melting and scattering of the discharge electrode to the inner surface of the glass tube. Examples of end-of-life conditions such as a decrease in the amount of light emission based on the emission and unstable emission due to the discharge of alkali components that do not contribute to discharge into the glass tube, transition to a state in which so-called non-light emission occurs frequently Known as.

  In addition, the so-called glass tube deformation phenomenon such as swelling (bulging) or bending of the glass tube, which is considered to be due to the high temperature of the glass tube due to heat generated during arc discharge, is also known.

  This deformation phenomenon is due to the fact that borosilicate glass contains an alkali component to lower the softening point, and that the xenon gas enclosed in the glass tube is heated by the temperature rise of the glass tube itself due to heat generation during arc discharge. It is presumed that a large factor is the point of expansion and deformation pressure / stress from the inside of the glass tube to the glass tube.

  That is, when looking at a special case in which light emission operation is repeatedly performed in a short time rather than a normal light emission operation in which light is emitted every time at an appropriate timing, a thermal shock accompanying light emission is repeatedly applied in a short time. Therefore, the temperature rise of the glass tube is larger than that in the normal light emitting operation, and therefore the glass tube resists the deformation pressure and stress when the rise temperature reaches the vicinity of the softening point that has been lowered. The present applicant speculates and estimates that the glass tube deformation phenomenon that the glass tube swells and curves as a result has occurred.

  As described above, it is well known and obvious that it is necessary to enhance the durability of the glass tube constituting the envelope of the flash discharge tube in order to improve the durability characteristics of the flash discharge tube. However, since it is widely recognized that a small thermal expansion coefficient has excellent heat resistance and thermal shock characteristics, the thermal expansion coefficient is small as a measure to improve the thermal and thermal shock characteristics of glass. The glass component was designed or selected as such.

  There is no exception in the field of discharge tubes, and as a measure to improve the heat resistance and thermal shock resistance, conventionally designed glass with a low thermal expansion coefficient, in other words, glass with a low thermal expansion coefficient is used. It was well-known and common to use as an envelope.

  Specifically, as a glass tube constituting the envelope, quartz glass that is mainly formed of silicon dioxide, has a low coefficient of thermal expansion, and thus has high heat resistance characteristics, high heat shock resistance characteristics, and high mechanical strength. Configurations that employ tubes are well known and common. The electrode pins constituting the discharge electrodes are generally employed because the above-mentioned tungsten has a high melting point of about 3400 ° C. and is relatively easy to process into electrode pins.

However, when actually seeing the thermal expansion coefficients of the quartz glass tube and tungsten, that of quartz glass is about 0.55 × 10 ⁻⁶ · K ⁻¹ , and that of tungsten is 4.4 to 4.5 × 10 6. Unlike ^-6 · K ^-1 , when trying to weld both of them directly by fusing quartz glass for hermetic sealing, a large distortion occurs in the quartz glass due to the difference in thermal expansion coefficient, and cracks occur. Conventionally, various means for preventing the occurrence of such cracks have been proposed or put into practical use.

For example, an intermediate glass body configured by arranging a plurality of glass tubes having different thermal expansion coefficients so that the thermal expansion coefficient sequentially changes in the axial direction of the quartz glass tube is prepared in advance, and the quartz glass is interposed through the intermediate glass body. The end glass tube formed from a conventional borosilicate glass whose thermal expansion coefficient is close to that of tungsten is first welded, and then the end glass tube and tungsten are hermetically sealed through a heating process. As a result, it is well known that the quartz glass tube and tungsten are indirectly hermetically sealed as a result. (Patent Document 1)
In addition, when the strength of the glass tube, which is the envelope of the flash discharge tube, is improved by using a quartz glass tube having a small thermal expansion coefficient as described above, it is naturally a discharge electrode in terms of life durability characteristics. This burden increases, and it is desired to improve the strength (durability) of the discharge electrode. For example, JP 2012-119205A discloses a glass tube and an anode provided at one end of the glass tube. In a flash discharge tube comprising a side electrode and a cathode side electrode provided at the other end of the glass tube, the glass tube is connected to a first glass tube and both ends of the first glass tube, respectively. A second glass tube connected through a stepped glass tube having a thermal expansion coefficient between the thermal expansion coefficient of the first glass tube and the second glass tube; Formed, and said glass Flash device is disclosed having a flash discharge tube and the flash discharge tube, wherein the ratio of the outer diameter of the anode electrode to the inside diameter of the tube is 43.5% or more. (Patent Document 2)
In addition, the UV-expanded xenon discharge tube that does not require the complicated processing steps to form the above-mentioned intermediate glass body and stepped glass tube with the adoption of the quartz glass tube, and has excellent durability, that is, thermal expansion of tungsten. The borosilicate glass tube, which has a higher softening point and improved durability, is made into a quartz glass tube by reducing the thermal expansion coefficient in the direction closer to the quartz glass tube than ordinary borosilicate glass designed to approximate the coefficient. An ultraviolet transmission xenon discharge tube adopted instead and an illumination device using the discharge tube are also well known. (Patent Document 3)
As described above, from the viewpoint of strengthening the glass tube for the purpose of enhancing the durability characteristics of the flash discharge tube, the quartz glass tube and the equivalent glass tube as disclosed in Patent Documents 1 and 2, In other words, the thermal expansion coefficient is extremely small, and it has high thermal shock resistance, as well as a glass tube with excellent mechanical strength against external physical impacts, or the softening point is lowered by containing an alkali component. It is general that the envelope of the flash discharge tube is constituted by a borosilicate glass tube as disclosed in Patent Document 3 designed so that the thermal expansion coefficient is small even in the designed borosilicate glass. . That is, as described above, in the glass field, designing a small thermal expansion coefficient is a common measure for improving the thermal shock resistance of the glass tube.

Japanese Patent No. 5262911 JP 2012-119205 A JP2013-62115A

  The flash discharge tubes disclosed in Patent Documents 1 and 2 are both quartz glass tubes having a low thermal expansion coefficient, a high thermal shock resistance and a large mechanical strength in order to strengthen the glass tube constituting the envelope. In order to use a glass tube having a durability function equivalent to that of the quartz glass tube, the difference in thermal expansion coefficient between the electrode pin and the glass tube constituting the envelope is taken into consideration, and the glass tube constituting the envelope is used. Because it has a configuration that uses an intermediate glass body and a stepped glass tube at both ends, it requires complicated processing steps to form the intermediate glass body and the stepped glass tube, greatly increasing the cost of the flash discharge tube. Had the problem of inviting.

  On the other hand, in Patent Document 3, the thermal expansion coefficient is made smaller in the direction approaching the quartz glass tube than that of a normal borosilicate glass tube, thereby increasing the softening point and providing more durable characteristics than the normal borosilicate glass tube. An improved borosilicate glass tube is used instead of a quartz glass tube, and an ultraviolet transmission xenon discharge tube that does not require the complicated processing steps described above has been disclosed. It is clear that it is a kind of borosilicate glass, and its durability function has a problem that does not reach the quartz glass tube.

  In view of the above problems, the present invention realizes a flash discharge tube capable of realizing a significant improvement in heat resistance and high heat shock resistance with respect to a borosilicate glass tube, and a flash discharge tube that can be formed at low cost. It is an object to provide a light irradiation device provided.

  A flash discharge tube according to the present invention is a flash discharge tube in which a discharge electrode is hermetically sealed at both ends of a light-transmitting envelope in a state where xenon gas is sealed inside the envelope. The arc discharge space formed surrounding at least the arc discharge region between the pair of discharge electrodes is composed of an aluminosilicate glass tube containing aluminosilicate as a main component and almost no alkali component. Features.

  According to such a configuration, the coefficient of thermal expansion of the aluminosilicate glass tube of the present invention is set to be larger than the coefficient of thermal expansion of the borosilicate glass tube containing an alkali component by being of a kind or design containing almost no alkali component. It will be possible. As a result, the softening point of the envelope can be made higher than that of the borosilicate glass tube, so that the heat resistance can be improved and the inner surface of the glass tube due to the thermal shock during arc discharge generated in the borosilicate glass tube. It is possible to drastically reduce the elution phenomenon of the alkali component to the heat resistance, thereby greatly improving the thermal shock resistance.

  In other words, if an envelope that forms an arc discharge space with an aluminosilicate glass tube that hardly contains an alkali component as described above is configured, the above-described conventional glass field in which the coefficient of thermal expansion is designed to be small. Despite the recognition and practice of glass tube strengthening measures that have been practiced, the endurance characteristics (heat resistance characteristics and thermal shock characteristics) of the phenomenon that occurred only in the envelope of the flash discharge tube, such as thermal shock during arc discharge It will be able to greatly improve.

  As a result, it is possible to greatly improve the light emission life durability characteristics of a flash discharge tube that is useful as a light source of a strobe device, which is one of light irradiation devices.

  According to a second aspect of the present invention, the envelope is formed of borosilicate glass and has an inner and outer diameter substantially equal to the inner and outer diameters of the aluminosilicate glass tube, and at least one end of the aluminosilicate glass tube The discharge electrode has an electrode pin forming an arc discharge space and an end outer diameter that is hermetically welded to the electrode pin and substantially equal to the outer diameter of the aluminosilicate glass tube. An anode bead having an anode bead hermetically sealed by being melt bonded to one end of the aluminosilicate glass tube through an end face of the anode bead, an electrode pin forming the arc discharge space, and the electrode pin A cathode bead that is hermetically welded and has a side portion outer diameter substantially equal to the inner diameter of the bonded glass tube, and is fixed to the tip of the electrode pin. Consists of a sintered body, is characterized by having a cathode that is hermetically sealed by being melted bonded through a side surface portion on the bonding glass tube.

  According to such a configuration, both the anode bead and the bonded glass tube are welded to the thickness portion of the end surface of the aluminosilicate glass tube, thereby realizing the welding in the axial direction instead of the radial direction of the aluminosilicate glass tube. Therefore, it is possible to greatly suppress the occurrence of inconveniences such as leakage due to a peeling phenomenon that may occur due to a difference in thermal expansion coefficient.

  Furthermore, the hermetic sealing operation of the cathode can be performed through a well-known bonded glass tube made of borosilicate glass in the same manner as in the past, and the conventional equipment and operating conditions in the hermetic sealing process are not complicated. It can be set to a situation that approximates.

  That is, the aluminosilicate glass tube is a glass tube having a higher softening point than the borosilicate glass tube, but its processing temperature is high, but it is much lower than the processing temperature of the quartz glass tube. It goes without saying that the hermetically sealing process of the anode and the cathode can be easily formed as compared with the case where a quartz glass tube that requires an intermediate glass body or the like is used.

  Further, in the invention according to claim 3, the anode bead is formed by winding the electrode bead directly around the electrode pin so as to have an outer diameter smaller than the inner diameter of the aluminosilicate glass tube, and the outer surface of the aluminosilicate glass tube. And a second bead formed by being wound around the first bead with a length shorter than the axial length of the first bead so as to have an outer diameter substantially equal to the diameter. To do.

  According to this configuration, the heat welding in the axial direction of the aluminosilicate glass tube and the anode in the axial direction of the aluminosilicate glass tube is realized through the end face of the second bead, and the influence on the welded portion between the first bead and the electrode pin. Can be reduced.

  Further, in the invention according to claim 4, the bonded glass tube has substantially the same inner and outer diameters including the same inner and outer diameters of the aluminosilicate glass tube, and is melt-bonded to both ends of the aluminosilicate glass tube through its end faces, The anode bead is formed to have a side surface outer diameter substantially equal to the inner diameter of the bonded glass tube, and is hermetically sealed by being melt bonded to the bonded glass tube through the side surface portion.

  According to such a configuration, the airtight attachment work of each of the anode and the cathode can be carried out via a bonded glass tube made of a well-known borosilicate glass, as in the past. It is possible to set a situation that is similar to the conventional situation without complicating.

  Further, the invention according to claim 5 is characterized in that the outer surface of the envelope is provided with a transparent conductive film to which a trigger voltage is applied.

  According to such a configuration, the same trigger voltage application configuration as before can be realized.

  According to a sixth aspect of the present invention, there is provided a strobe device including the flash discharge tube according to any one of the first to fifth aspects as a light source.

  According to such a configuration, an aluminosilicate glass tube containing almost no alkali component is used as an envelope constituting an arc discharge space, and a flash discharge tube having greatly improved heat resistance and thermal shock characteristics is used as a light source. Therefore, it is possible to provide a strobe device that is excellent in the light emission life durability characteristics and the short-time repeated light emission durability characteristics.

  According to the flash discharge tube of the present invention, since the envelope constituting the arc discharge space is composed of an aluminosilicate glass tube containing almost no alkali component, the elution phenomenon of the alkali component can be drastically reduced. As a result, high heat resistance characteristics and high thermal shock resistance characteristics can be realized. As a result, it is possible to provide a flash discharge tube which is excellent in lifetime durability characteristics for light emission and repeated light emission durability characteristics for a short time and is inexpensive.

  According to the light irradiation apparatus of the present invention, since the flash discharge tube according to the present invention having greatly improved heat resistance and thermal shock characteristics is used as a light source, the light emission life durability characteristics and the short-time repeated light emission durability characteristics are excellent. A light irradiation apparatus can be provided.

1 is a schematic view showing an embodiment of a flash discharge tube according to the present invention. Schematic showing an example of the manufacturing process of the anode of the flash discharge tube according to the embodiment Schematic showing a manufacturing process example of the cathode of the flash discharge tube according to the embodiment Schematic showing an example of the manufacturing process of the envelope of the flash discharge tube according to the embodiment Schematic showing a manufacturing process example of a flash discharge tube according to the embodiment The schematic block diagram which shows one Embodiment of the strobe device which is an example of the light irradiation apparatus using the flash discharge tube concerning this invention

  Hereinafter, a flash discharge tube according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view showing an embodiment of a flash discharge tube according to the present invention. As shown in the drawing, the flash discharge tube 1 has xenon at both ends of the envelope 2 and inside the envelope 2. An electrode pin 6 that forms part of the discharge electrode A (anode) via the anode bead 4 in a state in which the gas 3 is sealed, and an electrode pin that forms part of the discharge electrode C (cathode) via the cathode bead 5 7 is hermetically sealed.

The envelope 2 of the flash discharge tube 1 according to the present invention includes a first envelope that constitutes an appropriate space including an arc discharge space formed surrounding an arc discharge region formed between the discharge electrodes A and C. And a second envelope portion 9 (one end in the present embodiment) which is a bonded glass tube connected to at least one end of the first envelope portion 8. The enclosure portion 8 is composed of an aluminosilicate glass tube (for example, Glass 8253 manufactured by SCHOTT, etc.) containing almost no alkali component, and the second envelope portion 9 is a bonded glass tube connected to the aluminosilicate glass tube. Is composed of a borosilicate glass tube designed to have a low softening point. (For example, SCHOTT Glass 8487)
By the way, although the aluminosilicate glass tube itself is a conventionally well-known glass tube, in the present invention, as described above, the aluminosilicate glass tube containing almost no alkali component is used as an envelope for forming an arc discharge space. 2 is adopted.

  That is, it is an alkali oxide-free aluminosilicate glass tube that contains almost no alkali component used in the present invention, and its component composition is about 20 w% aluminum oxide, about 60 w% silicon dioxide, and the balance. It is glass comprised so that it may become less than 0.03 w% about the said alkali oxide which is an alkaline earth metal which occupies most of it as a main composition, and is an alkali component.

As a specific example, looking at the composition of the previous SCHOTT Glass 8253, 16.5 w% aluminum oxide, 61 w% silicon dioxide, 13 w% potassium oxide as an alkaline earth metal oxide, 8 w% barium oxide, The alkali oxide is configured to contain less than 0.02 w% sodium oxide and the like, and the alkali oxide is set to be less than 0.03 w% in total. Regarding the characteristics of the glass 8253, the softening point is about 1000 degrees, which is higher than about 700 to 830 degrees of the borosilicate glass containing an alkali component, and the thermal expansion coefficient is 4.7 × 10 ⁻⁶ · K. ^-1 , which is larger than 3.2 to 4.1 × 10 ⁻⁶ · K ⁻¹ of borosilicate glass and 0.55 × 10 ⁻⁶ · K ^{−1 of} quartz glass.

The discharge electrode A which is an anode is composed of an electrode pin 6 to which an anode bead 4 is welded and an external pin 10 welded to the electrode pin 6 as shown in the figure, and the electrode pin 6 has a thermal expansion coefficient. It is 4.4 to 4.5 × 10 ⁻⁶ · K ⁻¹ , and is composed of tungsten having a very high melting point of about 3400 ° C. The anode bead 4 is made of a conventionally known borosilicate glass (for example, Glass 8487 manufactured by SCHOTT), and a nickel-based metal such as nickel is adopted as the external pin 10.

  Further, the anode bead 4 is formed of a first anode bead 4a welded directly to the electrode pin 6 and a second anode bead 4b welded outside the first anode bead 4a. The second anode bead 4b is configured such that the outer diameter of the end thereof is substantially equal to the same as the outer diameter of the first envelope part 8 made of an aluminosilicate glass tube constituting the envelope 2. As will be described later, the first envelope portion 8 and the electrode pin 6 are hermetically sealed by being melt bonded to the thickness portion of the end surface of the first envelope portion 8 via the end surface. Is realized indirectly.

  The discharge electrode C, which is a cathode, was welded to an electrode pin 7 to which a cathode bead 5 is hermetically welded as shown in the figure, and a sintered electrode 11 attached to the electrode pin 7 by a method such as caulking, and the electrode pin 7. The cathode bead 5, the electrode pin 7 and the external pin 12 are made of borosilicate glass, tungsten, and nickel-based metal, respectively, like the discharge electrode A. Yes. The cathode bead 5 has a side part outer diameter that is substantially equal to the inner diameter of the second envelope part 9 and is melt-bonded to the second envelope part 9 via the side part as will be described later. This indirectly realizes hermetic sealing between the second envelope portion 9 and the electrode pin 7.

  Next, a schematic example of a process for manufacturing the flash discharge tube according to the first embodiment of the present invention will be briefly described with reference to FIGS.

  2 (a) and 2 (b) show a process schematic diagram for manufacturing the discharge electrode A as an anode, and FIGS. 3 (a) and 3 (b) show a process schematic diagram for manufacturing a discharge electrode C as a cathode. 4 (a) and 4 (b) show a process schematic diagram for manufacturing the envelope 2, and FIG. 5 shows a first embodiment of the present invention using each process member manufactured in FIGS. The process schematic diagram which manufactures a flash discharge tube is shown.

Both the discharge electrodes A and C shown in FIGS. 2 and 3 have a hollow cylindrical shape on tungsten having a thermal expansion coefficient of 4.4 to 4.5 × 10 ⁻⁶ · K ^{−1 as} the electrode pins 6 and 7. An anode bead 4 (first bead 4a and second bead 4b) and cathode bead 5 made of borosilicate glass having a thermal expansion coefficient of 3.2 to 4.1 × 10 ⁻⁶ · K ⁻¹ are shown in FIG. , Moved in the direction indicated by the arrow in FIG. 3 (a), and then inserted, and then heated by bead heating burners B1 and B2 as shown in FIG. 2 (b) and FIG. 3 (b), for example. By doing so, it is melt-bonded to the previous electrode pins 6 and 7. At this time, the difference in thermal expansion coefficient between the electrode pins 6 and 7 and the anode bead 4 and the cathode bead 5 is small, specifically, set to be 1 × 10 ⁻⁶ · K ⁻¹ or less. Therefore, it is possible to prevent the occurrence of inconvenience based on the difference in thermal expansion coefficient at the time of melt bonding by direct heating.

  As shown in FIG. 3B, the discharge electrode C further has the sintered electrode 11 attached to the electrode pin 7 through a caulking process, for example.

  4 (a) and 4 (b) are schematic views of a process for manufacturing the envelope 2 of the flash discharge tube according to the present invention, and a first envelope portion made of an aluminosilicate glass tube containing almost no alumina component. 8 and a second envelope part 9 comprising a borosilicate glass tube configured to contain an alumina component in order to lower the melting point and having a substantially equal inner / outer diameter including the same as the inner / outer diameter of the first envelope part 8. Is moved in the direction indicated by the arrow in FIG. 4 (a) and the ends thereof are butted together, for example, by heating with a burner B3 as shown in FIG. 4 (b). It is joined.

That is, the thermal expansion coefficient of the aluminosilicate glass tube forming the first envelope portion 8 is 4.6 × 10 ⁻⁶ · K ⁻¹ and the thermal expansion of the borosilicate glass tube forming the second envelope portion 9. When the coefficients of 3.2 to 4.1 × 10 ⁻⁶ · K ⁻¹ are compared, the difference is about 1 × 10 ⁻⁶ · K ⁻¹ , and the first envelope portion 8 and the first envelope 2 If the envelope part 9 is melt-bonded in the radial direction of the both, there is a risk of causing a defect due to the difference in thermal expansion coefficient, for example, a crack, but in the present invention, the first envelope part Since both the 8 and the second envelope part 9 are melt-bonded in the axial direction of each through the respective thicknesses, it is possible to eliminate the possibility of occurrence of problems due to the difference in thermal expansion coefficient.

  The first envelope portion 8 and the second envelope portion 9 function as a trigger electrode to which a trigger voltage is applied as necessary to the envelope 2 formed by fusion bonding as described above. It goes without saying that the transparent conductive film may be formed in a predetermined region on the outer surface by a known method.

  Next, as shown in FIG. 5, the process members such as the discharge electrodes A and C manufactured in FIGS. 2 to 4 are combined as follows.

  First, the discharge electrode A as an anode is moved in the direction of the arrow in FIG. 5, and the end surface of the second anode bead 4 b forming the anode bead 4 is moved to the end of the first envelope portion 8 of the envelope 2. The end face of the second envelope bead 4b and the end part of the first envelope part 8 are then brought into contact with each other by, for example, heating with a burner B4, and the thickness (end face) of the end part of the first envelope part 8 is made. The discharge electrode A, which is an anode, is hermetically sealed to the envelope 2 via the first envelope portion 8.

  Next, the discharge electrode B is moved in the direction of the arrow in FIG. 5, and the cathode bead 5 is inserted into the second envelope portion 9 of the envelope 2, and in that state, inside the envelope 2. The side surface of the cathode bead 5 and the inner surface of the second envelope part 9 are melt-bonded by heating the second envelope part 9 with, for example, the burner B5 while filling the desired amount of xenon gas 3, thereby The discharge electrode C as a cathode is hermetically sealed to the envelope 2 via the second envelope portion 9.

  Thereafter, although not shown in the drawings, the steps of setting the length of the external pins 10 and 12 to a desired length, the step of applying preliminary solder to the external pins 10 and 12 and the like are performed as necessary. The flash discharge tube 1 according to the present invention shown in FIG.

  As described above, the embodiment of the flash discharge tube 1 according to the present invention is configured without using an intermediate glass body or a stepped glass tube that requires a complicated processing step. It is clear that the manufacturing process described in 4 etc. can be simplified, and as a result, the flash discharge tube 1 according to the present invention can be provided at low cost.

  The flash discharge tube according to the present invention is not limited to the above-described embodiment. For example, the hermetically sealing discharge electrode A and the xenon gas sealing method can be variously changed as follows. Needless to say, it can be done.

  That is, in the above-described embodiment, the second envelope part 9 for hermetically sealing the discharge electrode C, which is a cathode, is melt bonded to only one end of the first envelope part 8, and the discharge electrode A is the first The anode bead 4 was directly melt-bonded to one end of the envelope portion 8 through its thickness, but the second envelope portion 9 was formed at both ends of the first envelope portion 8 to discharge the electrode. Of course, A may be melt-bonded via the second envelope portion 9. However, in this case, the anode bead 4 of the discharge electrode A needs to be formed to have an outer diameter smaller than the inner diameter of the second envelope portion 9 like the cathode bead 5, and the anode bead 4 corresponds to this configuration. It will be melt-bonded in the second envelope part 9 via its side face part.

  Further, the envelope 2 is constituted by only the first envelope portion 8 without joining the second envelope portion 9 which is a bonded glass tube, and the anode beads 4 and the cathodes of the discharge electrodes A and C, respectively. The outer diameter of the bead 5 is formed to be smaller than the inner diameter of the first envelope portion 8 and is elongated in the axial direction of the first envelope portion 8, for example, to have a dimension more than twice the inner diameter. Thus, it goes without saying that the anode bead 4 and the cathode bead 5 may be melt-bonded to the corresponding end portions of the first envelope portions 8 via the side surfaces thereof.

  Further, the envelope 2 is constituted by only the first envelope portion 8 without joining the second envelope portion 9 which is a bonded glass tube, and the anode beads 4 of the discharge electrodes A and C, the cathode A so-called pinch seal is formed in which a well-known foil electrode is formed by welding on a part of each electrode pin 6.7 without using the bead 5 and the foil electrode is pressure-bonded at the end of the first envelope portion 8. Of course, the airtight sealing between the discharge electrodes A and C and the first envelope part 8 may be realized by a method.

  Another example of a method for realizing the hermetic sealing process while enclosing the xenon gas 3 in the envelope 2 of the discharge electrode C is, for example, using a carbon heater instead of the burner B5. 5 includes the envelope 2 with the discharge electrode A sealed as shown in FIG. 5 excluding the burner B5, the discharge electrode C and the carbon heater, and a working space in which the inside can be evacuated and filled with xenon gas at a predetermined pressure. A method of filling the xenon gas in this vacuum vessel and performing melt bonding between the cathode bead 5 of the discharge electrode C and the second envelope portion 9 of the envelope 2 by a carbon heater. Of course, can be adopted.

  Furthermore, as another example of a method for enclosing the xenon gas 3 inside the envelope 2, the inside of the envelope 2 and the xenon gas are sealed through an exhaust pipe connected to the envelope 2. It is also possible to adopt a well-known method for tipping off the exhaust pipe afterwards.

  Next, an embodiment of a light irradiation apparatus according to the present invention will be described.

  FIG. 6 is a schematic configuration diagram showing an embodiment of a strobe device S which is an example of a light irradiation device using the flash discharge tube 1 according to the present invention.

  As shown in the figure, a strobe device S, which is an embodiment of a light irradiation device according to the present invention, includes a flash discharge tube 1 according to the present invention, which serves as a light source for illuminating a subject 14, and a flash discharge tube 1 according to the present invention. Through the reflector 15 that guides the emitted light toward the subject 14, the optical member 16 that is disposed between the flash discharge tube 1 and the subject 14, and blocks light in a short wavelength region, for example, light of 400 nm or less, and the optical member 16. The optical control means 17 for controlling the emission direction and the emission angle of the incident light, the light emission operation control means 18 for controlling the light emission operation of the flash discharge tube 1, and the like are provided.

  For this reason, when the flash discharge tube 1 performs the light emission operation by the light emission operation control means 18, the emitted light emitted from the flash discharge tube 1 is reflected directly and by the reflector 15 and reaches the optical member 16 and reaches a short wavelength. The light in the region is controlled to light that is blocked (for example, light that does not include light having a wavelength of 400 nm or less), and the irradiation angle is controlled by the optical control unit 17 so that the subject 14 is irradiated.

  At this time, the flash discharge tube according to the present invention as a light source of the strobe device as an example of the light irradiation device according to the present invention, that is, the arc discharge space of the envelope is constituted by an aluminosilicate glass tube, and the elution phenomenon of alkali components As a result, it is possible to realize high heat resistance and high thermal shock resistance by drastically reducing the lamp. As a result, it is possible to achieve significant improvements in the light emission lifetime durability characteristics as a device and the repeated light emission durability characteristics in a short time.

  Needless to say, the light irradiation device according to the present invention is not limited to the above-described strobe device, but may be an aircraft obstacle light, an emergency vehicle such as an aircraft or a patrol car installed at a high place such as a bridge or a high-rise building. Needless to say, the present invention can be applied to various light irradiation devices that use or can use a flash discharge tube as a light source, such as a warning light mounted on the camera.

  The flash discharge tube of the present invention comprises an aluminosilicate glass tube containing almost no alkali component in the arc discharge space of the envelope, and greatly reduces the elution phenomenon of the alkali component, thereby providing high heat resistance characteristics and high heat shock resistance characteristics. Therefore, the present invention can be applied to obtaining an inexpensive flash discharge tube that has excellent emission lifetime durability characteristics and short-time repeated emission durability characteristics.

  In addition, since the light irradiation device of the present invention uses the above-mentioned flash discharge tube as a light source, it is applicable to obtaining a light irradiation device that can realize significant improvement in the light emission life durability characteristics and the short-time repeated light emission durability characteristics. can do.

DESCRIPTION OF SYMBOLS 1 Flash discharge tube 2 Envelope 3 Xenon gas 4 Anode bead 4a 1st anode bead 4b 2nd anode bead 5 Cathode bead 6 Electrode pin 7 Electrode pin 8 1st envelope part 9 2nd envelope part 10 External pin 11 Sintered body (sintered electrode)
12 External pin 13 Main body 14 Subject 15 Reflector 16 Optical member 17 Optical control means 18 Light emission operation control means

In addition, as the glass tube constituting the envelope of the flash discharge tube, since the hermetically sealing operation with the electrode pin is performed by a heating process, conventionally, the thermal expansion coefficient is approximated to that of tungsten. It has been common to use borosilicate glass tubes designed to lower the softening point and lower the working temperature in the heating process. It is well known that the glass design for lowering the softening point in the borosilicate glass tube is realized by appropriately containing an alkali oxide such as sodium oxide or potassium oxide, which is an alkali component. Silicate glass tubes are recognized in the glass field as glass containing an alkali component. ("Alkali component" in the present invention means an alkali metal component such as sodium or potassium, and does not mean an alkaline earth metal component)

Looking at the composition of the previous SCHOTT Co. Glass8253 Examples, 16.5 W t% of aluminum oxide, 61w t% of silicon dioxide, 13w t% of calcium oxide as an oxide of an alkaline earth metal, 8w t% barium oxide, is configured to include a sodium oxide of less than 0.02 w t% alkali oxides, and is set to be less than 0.03 w t% in total for the alkali oxides. Regarding the characteristics of the glass 8253, the softening point is about 1000 degrees, which is higher than about 700 to 830 degrees of the borosilicate glass containing an alkali component, and the thermal expansion coefficient is 4.7 × 10 ⁻⁶ · K. ^-1 , which is larger than 3.2 to 4.1 × 10 ⁻⁶ · K ⁻¹ of borosilicate glass and 0.55 × 10 ⁻⁶ · K ^{−1 of} quartz glass.

Claims (6)

A flash discharge tube in which a discharge electrode is hermetically sealed at both ends of a translucent envelope with xenon gas sealed therein, wherein the envelope is at least between the pair of discharge electrodes. A flash discharge tube in which an arc discharge space formed by surrounding an arc discharge region is composed of an aluminosilicate glass tube containing aluminosilicate as a main component and almost no alkali component. The envelope is formed of borosilicate glass and has substantially the same inner and outer diameters including the same inner and outer diameters of the aluminosilicate glass tube, and is melt-bonded to at least one end of the aluminosilicate glass tube through an end surface. An anode bead having an outer diameter that is substantially equal to the outer diameter of the aluminosilicate glass tube, and the discharge electrode is hermetically welded to the electrode pin. An anode that is hermetically sealed by being melt-bonded to one end of the aluminosilicate glass tube through an end face of the anode bead, an electrode pin located in the arc discharge space, and an air-tight weld to the electrode pin A cathode bead having a side part outer diameter substantially equal to the inner diameter of the bonded glass tube, and a sintered body fixed to the tip part of the electrode pin; Rannahli, flash discharge tube according to claim 1, characterized in that it comprises a cathode which is hermetically sealed by being melted bonded through a side surface portion on the bonding glass tube. The anode bead has a first bead formed by being directly wound around the electrode pin so as to have an outer diameter less than an inner diameter of the aluminosilicate glass tube, and an outer diameter substantially equal to the outer diameter of the aluminosilicate glass tube. 3. The flash discharge according to claim 1, further comprising: a second bead formed around the first bead so as to have a length shorter than an axial length of the first bead. tube. The bonded glass tube has substantially the same inner and outer diameters as the inner and outer diameters of the aluminosilicate glass tube, and is melt-bonded to both ends of the aluminosilicate glass tube via its end faces, and the anode bead is the bonded glass 3. The flash according to claim 2, wherein the flash is formed to have an outer diameter that is substantially equal to an inner diameter of the tube, and is hermetically sealed by being melt-bonded into the bonded glass tube via the side surface. Discharge tube. The flash discharge tube according to any one of claims 1 to 4, further comprising a transparent conductive film formed on an outer surface of the envelope and to which a trigger voltage is applied. The light irradiation apparatus provided with the flash discharge tube in any one of Claims 1-5 as a light source.

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