JP2013062115A - Ultraviolet ray transmitting xenon discharge tube and luminaire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ultraviolet ray transmitting xenon discharge tube which is inexpensive and excels in durability as an ultraviolet ray source capable of generating ultraviolet rays.SOLUTION: An ultraviolet ray transmitting xenon discharge tube 1 of the present invention has at opposite ends of a package 2 hermetically sealed electrode pins 4 constituting discharge electrodes A and C via bead glass 3 while the inside of the package is filled with xenon gas 5. The discharge tube is composed using borosilicate glass whose thermal expansion coefficient is 3 to 3.3 (10K) for the package, tungsten whose thermal expansion coefficient is 4.4(10K) for the electrode pins 4, and borosilicate glass whose thermal expansion coefficient is 3.8 to 4.1 (10K), or midway between the thermal expansion coefficient of the package and that of the tungsten, for the bead glass. It is preferable that the thermal expansion coefficient of the bead glass be set in a such a way that a difference in thermal expansion coefficient between the bead glass and the package is larger than a difference in thermal expansion coefficient between the bead glass and a metal electrode.

Description

  The present invention mainly includes an ultraviolet transmission xenon discharge tube in which xenon gas is enclosed in an envelope having discharge electrodes hermetically sealed at both ends, and ultraviolet rays generated by flashing the enclosed xenon gas can be emitted to the outside. The present invention also relates to an illuminating device using the ultraviolet transmitting xenon discharge tube.

It is well known that ultraviolet rays are used in a wide variety of fields and industries, for example, in printing fields combined with ultraviolet curable resins, various sterilization / disinfection fields, and therapeutic fields.
Similarly, ultraviolet sources that generate ultraviolet rays are also well known, and mercury-transmitted lamps and fluorescent lamps that can continuously output ultraviolet rays, or ultraviolet-transmissive xenon that can instantaneously output powerful ultraviolet rays with less energy consumption by flashing operation. A discharge tube or the like is common.
By the way, when we look at the configuration of the above mercury lamp and ultraviolet transmission xenon discharge tube, it is necessary to derive ultraviolet rays generated by so-called discharge light emission outside the lamp or discharge tube, although there is a difference between continuous and instantaneous. Quartz glass having an excellent ultraviolet transmission function is used as an envelope serving as a lamp or a discharge tube for forming a light emission space.
This quartz glass is a glass mainly formed of silicon dioxide as is well known, and has an excellent ultraviolet ray transmission function as described above, and has a very low thermal expansion coefficient and high thermal shock resistance.

  In addition, for example, in the case of an ultraviolet transmitting xenon discharge tube, the discharge electrode hermetically sealed at both ends of the quartz glass as the envelope is an anode formed by a cathode electrode composed of an electrode pin and a sintered electrode, and the electrode pin itself. As the electrode pins are made of tungsten having a melting point of about 3200 ° C., which is sufficiently higher than the melting point of quartz glass, about 2000 ° C. Yes.

However, looking at the thermal expansion coefficients of the quartz glass and tungsten, it is about 0.55 (10 ⁻⁶ K ⁻¹ ) for quartz glass and 4.4 to 4.5 (10 ⁻⁶ K ⁻ ) for tungsten. ^{It is known} that, unlike ¹ ), if the two are directly welded by heating and melting the quartz glass, a large strain is generated in the quartz glass due to the difference in thermal expansion coefficient, and cracks are generated. Therefore, for example, an intermediate glass body constituted by arranging a plurality of glasses having different thermal expansion coefficients in advance so that the thermal expansion coefficient sequentially changes in the axial direction or radial direction of the quartz glass tube is prepared in advance. For example, a method of indirectly sealingly sealing quartz glass and tungsten through a metal is employed.
To describe a specific example, the difference in thermal expansion coefficient between the first glass material in which the difference in thermal expansion coefficient from quartz glass is controlled to be less than 1 (10 ⁻⁶ K ⁻¹ ) and the electrode pin made of tungsten is 1 Between the second glass material controlled to be less than (10 ⁻⁶ K ⁻¹ ), the difference in thermal expansion coefficient between each of the first and second glass materials is 1 (10 ⁻⁶ K ^−1). ) A third glass material controlled to be less than is provided to form an intermediate glass body, and the quartz glass and the electrode pins are heat-welded to each of the first and second glass materials forming the intermediate glass body. As a result, both the quartz glass and the electrode pin are indirectly hermetically sealed. (For example, JP 2010-232126 A)
Further, for example, a pinch seal method in which a metal foil welded to a part of an electrode pin as disclosed in Japanese Patent Application Laid-Open No. 2011-49094 is directly pressure-bonded with quartz glass including the welded portion is also well known.

On the other hand, a glass having a high ultraviolet transmittance and a thermal expansion coefficient close to that of tungsten has been proposed in, for example, Japanese Patent Application Laid-Open No. 2011-32162.
Japanese Patent Application Laid-Open No. 2011-32162 discloses an ultraviolet transmissive lamp having a reduced boron content and a thermal expansion coefficient particularly preferably in the range of 3.8 to 4.5 (10 ⁻⁶ K ⁻¹ ). High UV transmissive borosilicate glass is disclosed which is particularly preferred for use in

JP 2010-232126 A JP 2011-49094 A JP 2011-32162 A

  As described above, when obtaining an ultraviolet transmissive xenon discharge tube, usually, quartz glass having an excellent ultraviolet transmissive function is adopted for the envelope forming the lamp and discharge tube forming the discharge light emission space. Therefore, in order to achieve hermetic sealing with the discharge electrode, a complicated process using an intermediate glass body or a metal foil is required, resulting in an increase in the cost of the ultraviolet transmission xenon discharge tube.

  In addition, when using a glass having a high ultraviolet transmittance and a thermal expansion coefficient close to the thermal expansion coefficient of the discharge electrode, it is possible to prevent the complexity of the process for hermetic sealing as in the case of using quartz glass. In order to approximate the thermal expansion coefficient to that of the discharge electrode, the glass composition is designed to be larger than that of quartz glass, so the high thermal shock resistance, which is another major feature of quartz glass, is inevitably inferior. As a result, the durability as an ultraviolet transmitting xenon discharge tube is lowered as compared with the case of using quartz glass.

In view of such circumstances, the present invention provides an inexpensive and UV-transmissive xenon discharge tube that does not require a complicated processing step for hermetic sealing between the envelope and the discharge electrode, and also has excellent durability as a discharge tube. The purpose is to do.
In addition, the present invention provides an illuminating device having improved durability by introducing the characteristics of the discharge tube into the apparatus by using the ultraviolet transmission xenon discharge tube having excellent durability as a light source. Objective.

The ultraviolet transmissive xenon discharge tube of the present invention is an ultraviolet transmissive xenon discharge tube in which a discharge electrode is hermetically sealed through a bead in a state where xenon gas is sealed inside the envelope at both ends of the envelope. Compared to the thermal expansion coefficient of tungsten glass, which is a borosilicate glass having a thermal expansion coefficient of 3.8 to 4.1 (10 ⁻⁶ K ⁻¹ ) that approximates the thermal expansion coefficient of tungsten as an envelope. Electrode constituting a discharge electrode using borosilicate glass having a small thermal expansion coefficient of 3.0 to 3.3 (10 ⁻⁶ K ⁻¹ ) and having a high ultraviolet light transmission function and high thermal shock resistance As the pin, tungsten having a thermal expansion coefficient of 4.4 to 4.5 (10 ⁻⁶ K ⁻¹ ) is used, and as the bead, the thermal expansion coefficient is between the thermal expansion coefficient of the envelope and that of tungsten. 3.8-4.1 (10 ^-6 borosilicate glass ^{K -1)} is characterized by being configured using the tungsten glass.

  According to such a configuration, since the thermal expansion coefficient of the bead is close to the thermal expansion coefficient of tungsten which is an electrode pin, the bead is processed by a processing method using a known heating source such as a burner or a carbon heater. It can be heat-welded directly.

Furthermore, since the thermal expansion coefficient of the bead approximates that of the relatively small thermal expansion coefficient of the borosilicate glass that serves as the envelope, the heat welding between the bead and the envelope can be performed using a known heating source such as a carbon heater. The normal hermetic sealing method used allows direct heating and welding without causing large distortion in the envelope.
As a result, the difference between the respective thermal expansion coefficients is 1.0 (10 ⁻⁶ K ⁻¹ ) or more, and the envelope (the thermal expansion coefficient is relatively low) in which direct thermal welding is liable to generate cracks due to large strains. Both borosilicate glass having a small and high thermal shock resistance) and tungsten as an electrode pin can be hermetically sealed through one kind of bead.

  In the invention of claim 2, the thermal expansion coefficient of the bead is set so that the difference in thermal expansion coefficient with the envelope is larger than the difference in the number of thermal expansion systems with the electrode pins. Yes.

According to such a configuration, the heating conditions in the normal xenon discharge tube manufacturing process in which the so-called tungsten glass that matches the thermal expansion coefficient of tungsten, which is the electrode pin, is adopted for the envelope and the bead. It is possible to set the conditions very close to.
In the invention according to claim 3, the ultraviolet transmissive xenon discharge tube according to any one of claims 1 to 2 is used as a light source for illumination, and is further disposed between the ultraviolet transmissive xenon discharge tube and the subject. The illumination device is configured to include an optical member that blocks light in a short wavelength region of 400 nm or less, and always illuminates the subject with light through the optical member.

  According to such a configuration, the performance of the envelope in the ultraviolet transmission xenon discharge tube having a relatively small thermal expansion coefficient and high thermal shock resistance can be applied to improve the durability as an illumination device that illuminates the subject. .

According to the ultraviolet transmission xenon discharge tube of the present invention, an electrode pin that is tungsten constituting a discharge electrode through one kind of bead, and a borosilicate glass having a relatively small thermal expansion coefficient and high thermal shock resistance. Directly heat-welded to the envelope. That is, since it is not necessary to carry out a complicated process using an intermediate glass body or a metal foil, an ultraviolet transmissive xenon discharge tube having low cost and high thermal shock resistance can be obtained.
Moreover, according to the irradiation apparatus of this invention, the irradiation apparatus excellent in durability can be obtained.

The schematic front view which shows one Embodiment of the ultraviolet transmission xenon discharge tube which concerns on this invention Schematic showing an example of a manufacturing process of an ultraviolet transmission xenon discharge tube according to the same embodiment The schematic block diagram which shows one Embodiment of the illuminating device using the ultraviolet transmission xenon discharge tube which concerns on this invention.

The ultraviolet transmitting xenon discharge tube according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic front view showing an embodiment of an ultraviolet transmissive xenon discharge tube according to the present invention. As shown in the drawing, an ultraviolet transmissive xenon discharge tube 1 is provided at both ends of an envelope 2. The electrode pins 4 and 4 constituting a part of the discharge electrode A (anode electrode) and C (cathode electrode) are hermetically sealed through the bead 3 in a state where the xenon gas 5 is sealed inside 2. Yes.
Envelope 2 of ultraviolet transmitting xenon discharge tube according to the present invention has high ultraviolet transmittance and thermal expansion coefficient smaller than the thermal expansion coefficient of the tungsten glass described above from 3 to 3.3 (10 ^{- 6} K ⁻¹ ) borosilicate glass. (For example, SCHOTT Glass 8347)
The discharge electrode A is an anode electrode, and is composed of an electrode pin 4 to which a bead 3 is welded and a connection pin 7 welded to the electrode pin 4 as shown in the figure. Further, the electrode pin 4 has a thermal expansion coefficient. It is 4.4 to 4.5 (10 ⁻⁶ K ⁻¹ ) and is made of tungsten having a very high melting point. The connection pin 7 is made of nickel-based metal such as nickel.
The discharge electrode C indicates a cathode electrode, and an electrode pin 4 to which a bead 3 is welded as shown in the figure, a sintered electrode 6 attached to the electrode pin 4 by a method such as caulking, and a connection welded to the electrode pin 4 It consists of pins 7. The electrode pins 4 and the connection pins 7 are also made of tungsten or nickel metal.
The bead 3 of the ultraviolet light transmission xenon discharge tube according to the present invention has a thermal expansion coefficient between 3.8 to 4.1 (10) that is between the thermal expansion coefficient of the envelope 2 and the thermal expansion coefficient of the electrode pin 4 (tungsten). ⁻⁶ K ⁻¹ ) borosilicate glass. (For example, Nippon Electric Glass Xenon lamp glass tube BX-38, SCHOTT Glass 8487, etc.)
At this time, the thermal expansion coefficient of the bead 3 is set so that the difference in thermal expansion coefficient with the envelope 2 is larger than the difference in thermal expansion coefficient with the electrode pin 4. It is preferable because the heat processing conditions can be set without largely changing as compared with the manufacturing conditions of a normal xenon discharge tube using tungsten glass.

  Next, an example of a process for manufacturing the ultraviolet transmission xenon discharge tube according to the first embodiment of the present invention will be described with reference to FIGS.

2A and 2B are schematic views showing an example of the manufacturing process of the discharge electrode A which is an anode electrode, and FIGS. 2C and 2D are examples of the manufacturing process of the discharge electrode C which is a cathode electrode.
Both the discharge electrodes A and C have a hollow cylindrical shape in tungsten having a thermal expansion coefficient of 4.4 to 4.5 (10 ⁻⁶ K ⁻¹ ), which is the electrode pin 4 to which the connection pin 7 is welded, and exhibit thermal expansion. A bead 3 made of borosilicate glass having a coefficient of 3.8 to 4.1 (10 ⁻⁶ K ⁻¹ ) is moved in the direction indicated by an arrow in FIGS. 2 (a) and 2 (c) to show a broken line. And then heated and welded directly to the electrode pins 4 by heating with a first burner 8 for bead heating as shown in FIGS. 2 (b) and 2 (d), for example. Yes.
At this time, the difference between the thermal expansion coefficients of the electrode pins 4 and the beads 3 is set to be small, specifically, the thermal expansion coefficient difference between the two is set to 1 (10 ⁻⁶ K ⁻¹ ) or less. Therefore, the occurrence of inconvenience due to the direct heat welding can be prevented.
In the discharge electrode C, as shown in FIG. 2D, the sintered electrode 6 is further attached to the electrode pin 4 through a caulking process.

Next, as shown in FIG. 2 (e), the bead 3 of the discharge electrode A configured as described above has an expansion coefficient of 3 to 3.3 (10 ⁻⁶ K ^{− 1} ) is inserted into the end portion 2a of the borosilicate glass, and in this state, the end portion 2a of the envelope 2 is heated by heating the end portion 2a of the envelope 2 with the second burner 9 for heating the envelope. 2 and 3 are heated and welded by melting the beads 3. At this time, since the thermal expansion coefficient of the bead 3 is 3.8 to 4.1 (10 ⁻⁶ K ⁻¹ ) as described above, the difference from the thermal expansion coefficient of the envelope 2 is small. As a result, the discharge electrode A can be directly sealed to the one end 2a of the envelope 2.

Next, as shown in FIG. 2 (f), the bead 3 of the discharge electrode C is inserted into the other end 2b of the envelope 2 opposite to the end 2a to which the discharge electrode A is sealed. .
In this state, while the envelope 2 is filled with a desired amount of xenon gas 5, the end 2 b of the envelope 2 is heated by the sealing burner 10, for example, and the end 2 b of the envelope 2 and the beads 3 2 and 3 are heated and welded. As a result, the discharge electrode C is sealed to the one end 2b of the envelope 2 as in the case of the discharge electrode A described above. Thereafter, although not shown, the length of the connection pin 7 is cut to a desired length. The ultraviolet transmitting xenon discharge tube 1 according to the present invention shown in FIG. 1 is completed through a process of applying preliminary solder to the connection pins 7 and the like.
In addition, as another example of the hermetic sealing process in which the xenon gas 5 is sealed inside the envelope 2 of the discharge electrode C described above, for example, a carbon heater is used instead of the sealing burner 10, specifically, The envelope 2, the discharge electrode C, and the carbon heater sealed with the discharge electrode A shown in FIG. 2 (f) excluding the sealing burner 10 can be evacuated and filled with xenon gas at a predetermined pressure. It is arranged in a vacuum vessel provided with a work space, and a method of filling the xenon gas in this vacuum vessel and welding the bead 3 of the discharge electrode C and the one end 2b of the envelope 2 with a carbon heater is adopted. You can also.

  Next, the illuminating device 11 which concerns on embodiment of this invention is demonstrated.

  FIG. 3 is a schematic configuration diagram showing a strobe device which is an embodiment of the illumination device 11 using the ultraviolet transmission xenon discharge tube 1 according to the present invention. The strobe device is an illumination device that is useful as an artificial light source for illuminating a subject at the time of taking a photograph.

  As shown in the drawing, a strobe device, which is an embodiment of a lighting device 11 according to the present invention, includes an ultraviolet transmission xenon discharge tube 1 according to the present invention as a light source for illumination in a main body 12, and the ultraviolet transmission xenon discharge tube 1. Is arranged between the reflector 13 that guides the light emitted by the light emission toward the subject 17, the ultraviolet transmission xenon discharge tube 1, and the subject 17, and is an optical that blocks light in a short wavelength region, for example, light having a wavelength of 400 nm or less. The optical control means 15 which controls the emission direction of the light which injects through the member 14, the optical member 14, an emission angle, etc., the light emission control means 16 which controls the light emission operation | movement of the ultraviolet transmission xenon discharge tube 1, etc. are comprised. Yes.

  Therefore, when the ultraviolet transmission xenon discharge tube 1 performs a light emission operation by the light emission control means 16, the emitted light emitted from the ultraviolet transmission xenon discharge tube 1 is reflected directly and by the reflector 13 and reaches the optical member 14. Thus, the object 17 is irradiated after the irradiation angle is controlled by the optical control means 15 and is controlled by light (for example, light that does not include light having a wavelength of 400 nm or less). That is, the subject 17 is always illuminated by the light from which light in the short wavelength region is blocked by passing through the optical member 14.

At this time, the ultraviolet transmission xenon discharge tube 1 according to the present invention has the thermal expansion coefficient of 3 to 3.3 (10 ⁻⁶ K ⁻¹ ) as the envelope 2 as described above, and the thermal expansion. A borosilicate glass smaller than tungsten glass having a coefficient of 3.8 to 4.1 (10 ⁻⁶ K ⁻¹ ) is used. Therefore, the envelope 2 has higher thermal shock resistance than the above tungsten glass. doing.
As a result, the durability of the illuminating device 11 that illuminates the subject is improved by the characteristics having the high thermal shock resistance in the envelope 2 of the ultraviolet transmission xenon discharge tube 1.

The ultraviolet transmission xenon discharge tube according to the present invention is an electrode pin made of tungsten constituting a discharge electrode through one kind of bead, and a borosilicate glass having a relatively small thermal expansion coefficient and high thermal shock resistance. Since the envelope is directly heated and welded, there is no need to carry out a complicated process using an intermediate glass body or a metal foil, and therefore, an ultraviolet ray transmission xenon discharge tube having low cost and high thermal shock resistance can be obtained. Can do.
In the irradiation apparatus of the present invention, an optical member that blocks light in a short wavelength region is disposed between the ultraviolet transmission xenon discharge tube and the subject so that the subject is always illuminated with light through the optical member. Since the ultraviolet ray transmitting xenon discharge tube is configured and can be used as a light source of the lighting device, a lighting device having excellent durability can be obtained.

DESCRIPTION OF SYMBOLS 1 Ultraviolet light transmission xenon discharge tube 2 Envelope 3 Bead 4 Electrode pin 5 Xenon gas 6 Sintered electrode 7 Connection pin 8 1st burner 9 2nd burner 10 Sealing burner 11 Illuminating device 12 Main body 13 Reflector umbrella 14 Optical member 15 Optical Control means 16 Light emission control means 17 Subject

Claims (4)

An ultraviolet transmissive xenon discharge tube in which electrode pins constituting a discharge electrode are hermetically sealed at both ends of a translucent envelope with a xenon gas sealed inside the envelope. Borosilicate glass having a thermal expansion coefficient of 3 to 3.3 (10 ⁻⁶ K ⁻¹ ) is used as a vessel, and tungsten having a thermal expansion coefficient of 4.4 to 4.5 (10 ⁻⁶ K ⁻¹ ) is used as an electrode pin. And 3.8 to 4.1 (10 ⁻⁶ K ⁻¹ ) borosilicate glass whose thermal expansion coefficient is between the thermal expansion coefficient of the envelope and that of tungsten as a bead. Ultraviolet light transmission xenon discharge tube characterized by that. The ultraviolet transmission xenon discharge tube according to claim 1, wherein the thermal expansion coefficient of the bead is set so that a difference in thermal expansion coefficient with the envelope is larger than a difference in thermal expansion coefficient with the electrode pin. An irradiation device for irradiating a subject with light generated and emitted from the ultraviolet transmission xenon discharge tube according to claim 1, wherein the irradiation device is disposed between the ultraviolet transmission xenon discharge tube and the subject. And an optical member that blocks light in the short wavelength region, and illuminates the subject with light that is blocked from light in the short wavelength region via the optical member. The lighting device according to claim 3, wherein the light in the short wavelength region is light having a wavelength of 400 nm or less.

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