JP6709895B2 - Flash discharge tube and light irradiation device including the flash discharge tube - Google Patents

Description

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

Conventionally, a flash discharge tube has been used as a light source of a strobe device which is an artificial light source for illuminating a subject when taking a photograph, which is well known as a light irradiation device, and on the other hand, in a camera for taking a photograph, However, digitization using electro-optical elements such as CCD as a so-called photosensitive material for forming a subject image has progressed, and the number of shooting shots has increased dramatically. There is a strong demand for significant improvements.

By the way, in order to improve the light emission life endurance property of a strobe device which is one of the light irradiation devices, it is essential to improve the endurance property of a flash discharge tube to which a flash light is emitted. It goes without saying that it is necessary to reinforce each of the constituent materials of the flash discharge tube having such a configuration. That is, looking at the structure of the flash discharge tube, a pair of discharge electrodes are hermetically sealed at both ends of the glass tube forming the envelope of the flash discharge tube, with xenon gas sealed inside. It is well known that the above-mentioned constitution is provided, and conventionally, it has been strongly desired to strengthen 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 of the electrode pin itself.Furthermore, as the material of the electrode pin, light emission of a flash discharge tube is an arc. Since it is a discharge phenomenon and a large current is instantaneously generated, 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. It was common to use tungsten, which is a melting point metal.

Further, as the glass tube constituting the envelope of the flash discharge tube, since the work of hermetically sealing with the electrode pin is carried out by the heating step, conventionally, the thermal expansion coefficient is approximated to that of tungsten. It was common to employ borosilicate glass tubes designed to lower the softening point to lower the working temperature in the heating process. It is also well known that the glass design for lowering the softening point in the borosilicate glass tube is realized by adding an appropriate amount of an alkali oxide such as sodium oxide or potassium oxide which is an alkali component. The silicate glass tube is recognized in the glass field as a glass containing an alkaline component. (Note that the "alkali component" in the present invention means an alkali metal component such as sodium and potassium, and does not mean an alkaline earth metal component.)

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

One is the progress of glass tube cracks caused by the application of thermal shock to the glass tube itself by arc discharge, which is a phenomenon of dielectric breakdown that is a phenomenon that occurs only in the envelope of the flash discharge tube, and the melting and scattering of the discharge electrode on the inner surface of the glass tube. One of the causes is the deterioration of the light transmission function of the glass tube due to the evaporation/precipitation of the alkali component on the inner surface of the glass tube due to the application of thermal shock and the melting and scattering of the discharge electrode on the inner surface of the glass tube. A case in which the end of life state is indicated by a decrease in the amount of emitted light due to a decrease in the amount of emitted light and an unstable emission state due to the release of an alkaline component that does not contribute to discharge into the glass tube, such as a transition to a state in which a so-called non-emission phenomenon frequently occurs. Known as.

In addition, it is also known that a so-called glass tube deformation phenomenon such as swelling (bulging) or bending of the glass tube, which is considered to be caused by the temperature increase of the glass tube due to heat generation during arc discharge, is known.

The deformation phenomenon is that borosilicate glass contains an alkaline component to lower the softening point, and 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 major factor is that the glass tube expands to generate a deformation pressure/stress from the inside of the glass tube.

That is, looking at a special case where a light emitting operation is repeatedly performed in a short time instead of a normal light emitting operation in which light is emitted once at an appropriate timing, thermal shock due to light emission is repeatedly applied in a short time. Therefore, the temperature rise of the glass tube becomes larger than that during the normal light emission operation.Therefore, when the temperature rise reaches the vicinity of the previously lowered softening point, the glass tube resists the above deformation pressure and stress. The present applicant presumes/estimates that a glass tube deformation phenomenon in which the glass tube is swelled or curved as a result of being unable to be cut off is generated.

As described above, it is well known and clear that it is necessary to strengthen the durability of the glass tube forming the envelope of the flash discharge tube in order to improve the durability characteristics of the flash discharge tube. It is widely recognized that heat resistance and thermal shock resistance are excellent when the coefficient of thermal expansion is small. Therefore, as a measure to improve the heat resistance and thermal shock resistance of glass, the coefficient of thermal expansion is small. The glass components were designed or selected so that

Even in the field of discharge tubes, as a measure to improve heat resistance and thermal shock resistance, glass designed to have a small coefficient of thermal expansion, in other words, glass having a small coefficient of thermal expansion, has been used as a measure to realize improved heat resistance and thermal shock resistance. It was well known and common to use it as an envelope.

Specifically, as the glass tube forming the envelope, quartz glass formed mainly of silicon dioxide has a small coefficient of thermal expansion, and thus has high heat resistance characteristics and high thermal shock resistance characteristics, and also has high mechanical strength. The configuration employing tubes was well known and common. Incidentally, the electrode pin that constitutes the discharge electrode is generally adopted because the above-mentioned tungsten has a high melting point of about 3400° C. and is relatively easy to process into an electrode pin.

However, when actually looking at the respective 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. Unlike ^-6 ·K ^-1 , when the two are directly fused by heating and melting the quartz glass for air-tight sealing, a large strain occurs in the quartz glass due to the difference in the thermal expansion coefficient, and cracks occur. In the past, various means for preventing the occurrence of such cracks have been proposed or put into practical use.

For example, an intermediate glass body is prepared in advance by arranging a plurality of glass tubes having different thermal expansion coefficients so that the thermal expansion coefficient is sequentially changed in the axial direction of the quartz glass tube. The tube and the end glass tube formed from a conventional borosilicate glass, which has a thermal expansion coefficient similar to that of tungsten, are first welded, and then this end glass tube and tungsten are hermetically sealed via a heating process. As a result, it is well known that the quartz glass tube and the tungsten are indirectly hermetically sealed. (Patent Document 1)
Further, when the strength of the glass tube which is the envelope of the flash discharge tube is improved by adopting the quartz glass tube having a small coefficient of thermal expansion as described above, it is natural that the discharge electrode in terms of life and durability characteristics is used. Such a burden is increased, and it is desired to improve the strength (durability) of the discharge electrode. For example, in JP 2012-119205 A, a glass tube and an anode provided at one end of the glass tube are disclosed. In a flash discharge tube including 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, the second glass tube being connected via a stepped glass tube having a coefficient of thermal expansion between the coefficient of thermal expansion of the first glass tube and the coefficient of thermal expansion of the second glass tube. Disclosed is a flashlight discharge tube characterized in that the ratio of the outer diameter of the anode-side electrode to the inner diameter of the glass tube is 43.5% or more, and a strobe device equipped with this flashlight discharge tube. There is. (Patent Document 2)
It should be noted that the UV transmission xenon discharge tube, which is inexpensive and has excellent durability, does not require the complicated processing steps of forming the above-mentioned intermediate glass body and stepped glass tube due to the adoption of the quartz glass tube, that is, the thermal expansion of tungsten. A borosilicate glass tube with improved thermal resistance and a higher durability than that of ordinary borosilicate glass, which is designed to approximate the coefficient, is made closer to the quartz glass tube. The ultraviolet-transparent xenon discharge tube adopted instead and an illuminating device using this discharge tube are also well known. (Patent Document 3)
As described above, from the viewpoint of strengthening the glass tube for the purpose of strengthening 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 coefficient of thermal expansion is extremely small, and it has high thermal shock resistance properties, as well as a glass tube that is also extremely excellent in mechanical strength against external physical shocks, or it contains an alkali component to lower the softening point. Even with the designed borosilicate glass, it was common to configure the envelope of the flash discharge tube with the borosilicate glass tube as disclosed in Patent Document 3 designed to have a small thermal expansion coefficient. .. That is, as described above, in the field of glass, designing a small coefficient of thermal expansion has been a common measure for improving the thermal shock resistance of glass tubes.

Japanese Patent No. 5262911 JP, 2012-119205, A JP, 2013-62115, A

The flash discharge tubes disclosed in Patent Documents 1 and 2 are quartz glass tubes having a small thermal expansion coefficient and high thermal shock resistance and large mechanical strength in order to strengthen the glass tube constituting the envelope. Or, in order to use a glass tube having a durability function equivalent to that of the quartz glass tube, the difference between the thermal expansion coefficients of the electrode pins and the glass tube forming the envelope is taken into consideration, and the glass tube forming the envelope described above. Since both ends of the intermediate glass body and the stepped glass tube are provided with a configuration, a complicated processing step for forming the intermediate glass body and the stepped glass tube is required, and the cost of the flash discharge tube is significantly increased. It had a problem of inviting.

On the other hand, in Patent Document 3, the thermal expansion coefficient is made smaller in the direction closer to the quartz glass tube than that of the ordinary borosilicate glass tube, so that the softening point is increased and the durability characteristic is made higher than that of the ordinary borosilicate glass tube. The improved borosilicate glass tube is adopted instead of the quartz glass tube, and the UV transparent xenon discharge tube that does not require the complicated processing steps is disclosed, and it does not cause a significant cost increase. However, it is clear that it is a kind of borosilicate glass, and it has a problem that the quartz glass tube has no endurance function.

In view of the above problems, the present invention provides a flash discharge tube that can be formed at low cost while realizing a significantly high heat resistance property and a high heat shock resistance property for a borosilicate glass tube, and a flash discharge tube thereof. It is an object to provide a light irradiation device provided with the light irradiation device.

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-transmissive envelope with xenon gas sealed therein. Is configured by an aluminosilicate glass tube containing an aluminosilicate as a main component and having an alkali component of less than 0.03 wt% as an arc discharge space formed around at least a pair of the discharge electrodes. And has a substantially equal inner and outer diameter including the same as the inner and outer diameters of the aluminosilicate glass tube and is formed of borosilicate glass and melt-bonded to at least one end of the aluminosilicate glass tube through an end surface. It is characterized by having a joined glass tube.

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 designing a type containing almost no alkali component or by designing. You can do it. As a result, the softening point of the envelope can be made higher than that of the borosilicate glass tube, and therefore the heat resistance characteristics 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 alkaline component into the, and thereby to significantly improve the thermal shock resistance property.

That is, if the envelope that forms the arc discharge space is formed of an aluminosilicate glass tube containing almost no alkali component as described above, in the conventional glass field that the thermal expansion coefficient is designed to be small as described above. Although it is different from the conventional method of strengthening glass tubes, which is recognized and practiced, the durability characteristics (heat resistance characteristics and thermal shock resistance characteristics) against the thermal shock at the time of arc discharge that occurred only in the envelope of the flash discharge tube It can be greatly improved.

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

In the invention according to claim 2, the discharge electrode has an electrode pin located in the space of the arc discharge region and an end outer diameter that is airtightly welded to the electrode pin and is substantially equal to the outer diameter of the aluminosilicate glass tube. An anode bead, which is welded to one end of the aluminosilicate glass tube through an end face of the anode bead to be hermetically sealed, an electrode pin located in the arc discharge space, and an airtight seal to the electrode pin. It consists of a cathode bead that is welded and has a side surface outer diameter that is less than the inner diameter of the bonded glass tube and that can be hermetically sealed, and a sintered body that is fixed to the tip of the electrode pin. And a cathode which is hermetically sealed by being melt-bonded.

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, whereby the aluminosilicate glass tube is welded not in the radial direction but in the axial direction. Therefore, it is possible to greatly suppress the occurrence of inconveniences such as leakage due to a peeling phenomenon that may occur due to the difference in thermal expansion coefficient.

Further, the airtight sealing work of the cathode can be carried out through the well-known bonded glass tube made of borosilicate glass as in the conventional case, so that the equipment and working conditions in the airtight sealing work process are not complicated. It can be set to a situation similar to.

That is, the aluminosilicate glass tube is a glass tube having a higher softening point than the borosilicate glass tube, so the processing temperature is high, but it is much lower than the processing temperature of the quartz glass tube, and thus, as described above, It is needless to say that the step of hermetically sealing the anode and the cathode can be easily formed as compared with the case of using a quartz glass tube which requires an intermediate glass body or the like.

Further, in the invention according to claim 3, the anode bead is directly wound 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 structure, the heat welding 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 of the first bead and the electrode pin. Can be made smaller.

Further, in the invention according to claim 4, in the discharge electrode , 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 the end surfaces are provided at both ends of the aluminosilicate glass tube. Fusion bonding through, consisting of an electrode pin located in the space of the arc discharge region and an anode bead that is airtightly welded to the electrode pin and has a side surface outer diameter that is less than the inner diameter of the bonding glass tube and can be hermetically sealed, An anode that is hermetically sealed by being melt-bonded in the bonded glass tube through a side surface, an electrode pin that is located in the arc discharge space, and an electrode pin that is hermetically welded to the electrode pin and that is less than the inner diameter of the bonded glass tube and hermetically sealed. It consists of a cathode bead having a side surface outer diameter that can be attached and a sintered body fixed to the tip of the electrode pin, and is hermetically sealed by being melt-bonded through the side surface in the bonded glass tube. And a cathode .

According to such a configuration, the work of hermetically sealing each of the anode and the cathode can be carried out through the well-known bonded glass tube made of borosilicate glass as in the conventional case. It will be possible to set the situation similar to the previous one 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.

Further, the invention according to claim 6 is characterized in that a strobe device comprising the flash discharge tube according to any one of claims 1 to 5 as a light source is provided.

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

According to the flash discharge tube of the present invention, since the envelope forming the arc discharge space is made of an aluminosilicate glass tube containing almost no alkali component, the elution phenomenon of the alkali component can be drastically reduced. Thus, it is possible to realize high heat resistance characteristics and high thermal shock resistance characteristics, and as a result, it is possible to provide an inexpensive flash discharge tube which is excellent in life endurance characteristics against light emission and repeated light emission durability characteristics in a short time.

According to the light irradiation device of the present invention, since the flash discharge tube according to the present invention, which has significantly improved heat resistance and heat shock resistance, is used as a light source, it has excellent emission life durability and short-time repeated emission durability. A light irradiation device can be provided.

Schematic diagram showing an embodiment of a flash discharge tube according to the present invention Schematic showing an example of a manufacturing process of an anode of a flash discharge tube according to the same embodiment Schematic showing an example of the manufacturing process of the cathode of the flash discharge tube according to the same embodiment Schematic showing an example of a manufacturing process of the envelope of the flash discharge tube according to the embodiment. Schematic showing an example of a manufacturing process of the flash discharge tube according to the embodiment. 1 is a schematic configuration diagram showing an embodiment of a strobe device which is an example of a light irradiation device using a flash discharge tube according to the present 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 figure, the flash discharge tube 1 has xenon inside the envelope 2 at both ends of the envelope 2. An electrode pin 6 forming a part of the discharge electrode A (anode) through the anode bead 4 and an electrode pin forming a part of the discharge electrode C (cathode) through the cathode bead 5 in a state where the gas 3 is enclosed. 7 is hermetically sealed.

The envelope 2 of the flash discharge tube 1 according to the present invention is a first envelope that constitutes an appropriate space including an arc discharge space formed by surrounding an arc discharge region formed between the discharge electrodes A and C. The first envelope unit 8 and the second envelope unit 9 (one end in the present embodiment), which is a bonded glass tube connected to at least one end of the first envelope unit 8, are configured to further include the first outer unit. The envelope portion 8 is composed of an aluminosilicate glass tube containing almost no alkali component (for example, Glass 8253 manufactured by SCHOTT Co., Ltd.), and a second envelope portion 9 which is a joined glass tube connected to the aluminosilicate glass tube. Consists of a borosilicate glass tube designed to have a low softening point. (For example, Glass 8487 by SCHOTT)
By the way, although the aluminosilicate glass tube itself is a conventionally 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. It is adopted as 2.

That is, contains little alkaline ingredients that are employed in the present invention, an aluminosilicate glass tube alkali oxide free, its chemical composition, from about 20 w t% aluminum oxide, about 60 w t% of silicon dioxide, and wherein an alkaline earth metal occupying most of the balance as main composition, for the alkali oxide is an alkali component is a glass that is configured to be less than 0.03 w t%.

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° C., which is higher than about 700 to 830° C. of 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 the anode bead 4 is welded and an external pin 10 welded to the electrode pin 6 as shown in the figure. Further, the electrode pin 6 has a coefficient of thermal expansion. It is made of tungsten, which has a melting point of 4.4 to 4.5×10 ⁻⁶ ·K ⁻¹ and a melting point of about 3400° C., which is extremely high. The anode bead 4 is made of conventionally known borosilicate glass (for example, Glass 8487 manufactured by SCHOTT), and the external pin 10 is made of nickel-based metal such as nickel.

Further, the anode bead 4 is formed of a first anode bead 4a directly welded to the electrode pin 6 and a second anode bead 4b welded to the outside of the first anode bead 4a. The second anode bead 4b is configured such that the outer diameter of its end portion is substantially equal to the outer diameter of the first envelope portion 8 made of an aluminosilicate glass tube that constitutes the envelope 2. As will be described later, the first envelope portion 8 and the electrode pin 6 are hermetically sealed by melt-bonding to the thickness portion of the end face of the first envelope portion 8 through the end face thereof. Is achieved indirectly.

The discharge electrode C, which is the cathode, is welded to the electrode pin 7 on which the cathode bead 5 is hermetically welded as shown in the figure, and the sintered electrode 11 and the electrode pin 7 attached to the electrode pin 7 by a method such as caulking. Like the discharge electrode A, these cathode beads 5, electrode pins 7, and external pins 12 are made of borosilicate glass, tungsten, and nickel-based metal, respectively. There is. The cathode bead 5 has a side surface outer diameter substantially equal to the inner diameter of the second envelope portion 9, and is melt-bonded to the inside of the second envelope portion 9 via the side surface portion as described later. As a result, the airtight seal between the second envelope portion 9 and the electrode pin 7 is indirectly achieved.

Next, a schematic example of a process of 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 schematic steps of manufacturing the discharge electrode A that is an anode, and FIGS. 3(a) and 3(b) show schematic steps of manufacturing the discharge electrode C that is a cathode, FIGS. 4A and 4B are schematic views of steps for manufacturing the envelope 2, and FIG. 5 shows a first embodiment of the present invention using the process members manufactured in FIGS. 2 to 4. The schematic diagram of the process of manufacturing the flash discharge tube is shown.

In both discharge electrodes A and C shown in FIGS. 2 and 3, the electrode pins 6 and 7 having a coefficient of thermal expansion of 4.4 to 4.5×10 ⁻⁶ K ⁻¹ are provided in a hollow cylindrical shape. An anode bead 4 (first bead 4a and second bead 4b) and a 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. 3A, it is moved in the direction indicated by the arrow in FIG. 3A and inserted, and then heated by bead heating burners B1 and B2 as shown in FIGS. 2B and 3B, for example. By doing so, they are melt-bonded to the electrode pins 6 and 7. At this time, the difference in the coefficient of thermal expansion between the electrode pins 6, 7 and the anode bead 4 and the cathode bead 5 is small, specifically, set so as to be 1×10 ⁻⁶ ·K ⁻¹ or less. Therefore, it is possible to prevent the occurrence of inconvenience due to the difference in the thermal expansion coefficient during the melt bonding by the direct heating.

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

4(a) and 4(b) are schematic views of a process of manufacturing the envelope 2 for a flash discharge tube according to the present invention, which is a first envelope part made of an aluminosilicate glass tube containing almost no alumina component. 8 and a second envelope portion 9 made of a borosilicate glass tube containing an alumina component for lowering the melting point and having substantially the same inner and outer diameters as those of the first outer envelope portion 8. 4 and (a) are moved in a direction indicated by an arrow in FIG. 4(a) and end portions thereof are butted against each other, and are heated by, for example, 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. Comparing the coefficients 3.2 to 4.1×10 ⁻⁶ ·K ⁻¹ , the difference is about 1×10 ⁻⁶ ·K ^−1, which is the same as the first envelope portion 8 and the first envelope unit 8. When the two envelope parts 9 and the two envelope parts are melt-bonded in the radial direction, there is a possibility that defects due to the difference in the thermal expansion coefficient, such as cracks, may occur. However, in the present invention, the first envelope part is used. Since both 8 and the second envelope portion 9 are melt-bonded to each other in the axial direction through the respective thicknesses, it is possible to eliminate the possibility of causing a problem due to the difference in thermal expansion coefficient.

It should be noted that 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 on a predetermined region of the outer surface of the transparent conductive film by a known method.

Next, as shown in FIG. 5, the respective 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, which is the anode, is moved in the direction of the arrow in FIG. 5, and the end face of the second anode bead 4b forming the anode bead 4 is set to the end of the first envelope portion 8 of the envelope 2. The end surface of the second anode bead 4b and the end portion of the first envelope portion 8 are brought into contact with each other and then heated by, for example, a burner B4 so that the thickness of the end portion of the first envelope portion 8 (end surface) And the discharge electrode A, which is an anode, is air-tightly attached 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, the cathode bead 5 thereof is inserted into the second envelope portion 9 of the envelope 2, and in that state, inside the envelope 2. The second envelope portion 9 is heated by, for example, a burner B5 while being filled with a desired amount of xenon gas 3, so that the side surface of the cathode bead 5 and the inner surface of the second envelope portion 9 are fusion-bonded to each other. The discharge electrode C, which is a cathode, is airtightly attached to the envelope 2 via the second envelope portion 9.

After that, although not shown in the drawings, a step of setting the length of the external pins 10 and 12 to a desired length, a step of preliminarily soldering the external pins 10 and 12 and the like are performed as necessary, so that The flash discharge tube 1 according to the present invention shown in FIG.

As described above, in the embodiment of the flash discharge tube 1 according to the present invention, since it is configured without using the intermediate glass body and the stepped glass tube that require complicated processing steps, It is clear that the manufacturing process described in 4 and the like 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, and for example, the hermetically sealed construction method of the discharge electrode A, the xenon gas filling construction method, and the like may be variously changed as follows. It goes without saying that you can do it.

That is, in the above-described embodiment, the second envelope portion 9 for hermetically sealing the discharge electrode C, which is the cathode, is melt-bonded to only one end of the first envelope portion 8, and the discharge electrode A is first joined. Although the anode bead 4 is directly melt-bonded to one end of the envelope portion 8 through its thickness, the second envelope portion 9 is formed at both ends of the first envelope portion 8 and the discharge electrode is formed. It is needless to say that the A may be fusion-bonded via the second envelope portion 9 as well. However, in this case, the anode bead 4 of the discharge electrode A needs to be formed so that the outer diameter thereof is smaller than the inner diameter of the second envelope portion 9 similarly to the cathode bead 5, and the anode bead 4 corresponds to this structure. It will be melt-bonded in the second envelope portion 9 via its side surface portion.

Further, the envelope 2 is configured by only the first envelope portion 8 without joining the second envelope portion 9 which is a joined 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, formed so as to have a dimension that is twice or more the inner diameter. Therefore, it is needless to say that the anode bead 4 and the cathode bead 5 may be melt-bonded to the ends of the corresponding first envelope portion 8 via the side surfaces thereof.

Further, the envelope 2 is constituted only by the first envelope part 8 without joining the second envelope part 9 which is a joined glass tube, and the anode beads 4 and the cathode of the discharge electrodes A and C, respectively. A so-called pinch seal in which a well-known foil electrode provided by welding is formed 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 portion 8 may be realized by a method.

Further, as another example of the method for realizing the airtight adhesion process while enclosing the xenon gas 3 inside the envelope 2 of the discharge electrode C, for example, a carbon heater is used instead of the burner B5. 5 is provided with a discharge space A shown in FIG. 5 excluding the burner B5, a discharge electrode C, and a carbon heater, and a working space capable of evacuating the interior and filling with xenon gas at a predetermined pressure. Placed in a vacuum container, in which the xenon gas is filled and the cathode bead 5 of the discharge electrode C and the second envelope part 9 of the envelope 2 are melt-bonded by a carbon heater. Of course, can be adopted.

Further, as another example of the method of enclosing the xenon gas 3 inside the envelope 2, the inside of the envelope 2 is exhausted and the xenon gas is enclosed via an exhaust pipe connected to the envelope 2. It is also possible to adopt a known construction method in which the exhaust pipe is chipped off after that.

Next, an embodiment of the light irradiation device 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 flash device S, which is an embodiment of a light irradiation device according to the present invention, has a flash discharge tube 1 according to the present invention, which is a light source for illuminating a subject 14, in a main body 13, and this flash discharge tube 1 Via the reflector 15, which guides the emitted light of toward the subject 14 direction, the optical member 16 arranged between the flash discharge tube 1 and the subject 14 to block light in the short wavelength region, for example, light of 400 nm or less, It is configured by including an optical control means 17 for controlling the emission direction, the emission angle, etc. of the light that is incident as a light, a light emission operation control means 18 for controlling the light emission operation of the flash discharge tube 1.

Therefore, when the flash discharge tube 1 performs the light emitting operation by the light emitting operation control unit 18, the emitted light emitted from the flash discharge tube 1 reaches the optical member 16 directly and reflected by the reflector 15, and reaches the short wavelength. The light in the area is controlled to be blocked light (for example, light that does not include light having a wavelength of 400 nm or less), and the irradiation angle and the like are controlled by the optical control unit 17 to irradiate the subject 14.

At this time, a flash discharge tube according to the present invention as a light source of a strobe device which is an example of a light irradiation apparatus according to the present invention, that is, an arc discharge space of an envelope is configured by an aluminosilicate glass tube, and an elution phenomenon of an alkaline component is performed. It is possible to realize high heat resistance characteristics and high heat shock resistance characteristics by drastically reducing the light emission, and as a result, it is possible to use strobe lamps that are excellent in life endurance characteristics against light emission and short-term repeated light emission endurance characteristics and are inexpensive. It is possible to realize a significant improvement in the light emission life durability property of the device and the repeated light emission durability property in a short time.

Needless to say, the light irradiation device according to the present invention is not limited to the strobe device described above, and for example, an aircraft obstacle light installed in a high place such as a bridge or a high-rise building, an emergency vehicle such as an aircraft or a police car. It is needless to say that the present invention can be applied to various light irradiating devices that use or can use a flash discharge tube as a light source, such as a warning light mounted on the.

The flash discharge tube of the present invention comprises an arc discharge space of an envelope with an aluminosilicate glass tube containing almost no alkali component, and by highly reducing the elution phenomenon of the alkali component, high heat resistance characteristics and high thermal shock resistance characteristics. Therefore, the present invention can be applied to obtain an inexpensive flash discharge tube which is excellent in the light emission life endurance property and the short-term repeated light emission endurance property.

Further, since the light irradiation device of the present invention uses the above-mentioned flash discharge tube as a light source, it is applied to obtain a light irradiation device capable of significantly improving the light emission life endurance property and the repeated light emission endurance property in a short time. can do.

1 flash discharge tube 2 envelope 3 xenon gas 4 anode bead 4a first anode bead 4b second anode bead 5 cathode bead 6 electrode pin 7 electrode pin 8 first envelope part 9 second envelope part 10 external pin 11 Sintered body (sintered electrode)
12 external pin 13 body 14 subject 15 reflector 16 optical member 17 optical control means 18 light emission operation control means

Claims (6)

A flash discharge tube in which a discharge electrode is hermetically sealed at both ends of a light-transmissive envelope in which xenon gas is sealed, wherein the envelope has at least a pair of discharge electrodes. The arc discharge space formed around the arc discharge region is composed of an aluminosilicate glass tube whose main component is aluminosilicate and whose alkali component is less than 0.03 wt %, and is made of borosilicate glass. A flash discharge comprising a bonded glass tube that is formed and has a substantially equal inner and outer diameter including the same inner and outer diameters of the aluminosilicate glass tube , and that is fused and bonded to at least one end of the aluminosilicate glass tube through an end face. tube. The discharge electrode comprises an electrode pin located in the space of the arc discharge region and an anode bead that is hermetically welded to the electrode pin and has an end outer diameter substantially equal to the outer diameter of the aluminosilicate glass tube. An anode which is hermetically sealed by being welded and bonded to one end of the glass tube through the end face of the anode bead, an electrode pin located in the arc discharge space, and an inner diameter of the bonded glass tube which is airtightly welded to the electrode pin Less than and consisting of a cathode bead having a side surface outer diameter that can be hermetically sealed and a sintered body fixed to the tip of the electrode pin, and is melted and bonded to the inside of the bonding glass tube through the side surface part. The flash discharge tube according to claim 1, further comprising a cathode that is hermetically attached. The anode bead has a first bead formed by being directly wound around the electrode pin so as to have an outer diameter smaller than the inner diameter of the aluminosilicate glass tube, and an outer diameter substantially equal to the outer diameter of the aluminosilicate glass tube. The flash discharge tube according to claim 2, further comprising a second bead formed by winding the first bead around the first bead so as to have a length shorter than an axial length of the first bead. The discharge electrode has substantially equal inner and outer diameters including the inner and outer diameters of the joined glass tube being the same as the 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, and the arc discharge It consists of an electrode pin located in the space of the region and an anode bead that is airtightly welded to this electrode pin and has a side surface outer diameter that is less than the inner diameter of the bonded glass tube and that can be hermetically sealed, and through the side surface in the bonded glass tube. An anode that is hermetically sealed by being melt-bonded, an electrode pin that is located in the arc discharge space, and a side surface outer diameter that is hermetically welded to the electrode pin and is less than the inner diameter of the bonded glass tube and that can be hermetically sealed. A cathode bead and a sintered body fixed to the tip of the electrode pin, and a cathode hermetically sealed by being melt-bonded through the side surface in the bonded glass tube. The flash discharge tube according to claim 1 . The flash discharge tube according to claim 1, further comprising a transparent conductive film formed on an outer surface of the envelope and to which a trigger voltage is applied. A light irradiation device comprising the flash discharge tube according to claim 1 as a light source.

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