JP2014086357A - Rare gas discharge tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish a rare gas discharge tube which has high reliability in junction between an external electrode extending along an outer side face of a glass bulb and external lead wires extending from both ends of the glass bulb and improves duration reliability, electrical properties, and workability.SOLUTION: Entire discharge electrode parts 8a, 9a of external electrodes 8, 9 directly affixed to an outer side face 2a of a glass bulb 2 and the outer side face 2a of the glass bulb 2 of parts other than the discharge electrode parts 8a, 9a are covered by a cylindrical insulation tube 10 of which infrared ray permeability is high and which has insulation and heat shrinkage properties. Portions of the external electrodes 8, 9 extending from the portions covered by the insulation tube 10 are electrically joined to other end sides of a pair of external lead wires 6, 7 of which the one end sides are buried in a glass bead 3 so as not to be exposed within the glass bulb 2, by spot welding.

Description

  The present invention relates to a rare gas discharge tube, and more specifically, a rare gas is sealed in a discharge chamber in a glass bulb, and a pair of electrodes (external electrodes) are provided on the outer surface of the glass bulb. The present invention relates to a rare gas discharge tube that emits excimer light by barrier discharge.

  Conventionally, as this type of discharge tube, for example, there is one proposed as a fluorescent lamp in “JP 2002-164021 A (Patent Document 1)” (see FIG. 18).

  A discharge medium mainly composed of a rare gas is sealed in a translucent airtight container 80 in which a pair of external electrodes 81 are disposed on the outer surface and a phosphor layer is disposed on the inner surface side, The front end portion 84 of the external lead wire 83 embedded in the end portion of the translucent airtight container 80 is connected to one end portion of the external electrode 81 in a state where the 82 is not exposed in the translucent airtight container 80. ing.

JP 2002-164021 A

  By the way, in the fluorescent lamp, an external electrode containing aluminum is used to increase the reflectivity of ultraviolet light emitted from the discharge tube, and the tip of the external lead wire is connected to one end of the external electrode containing aluminum. Solder is used, and there are the following problems in solder joining of electrodes containing aluminum.

(1) When soldering an electrode containing aluminum and a lead wire, a solder containing 10 to 20% zinc or a special flux may be used, but generally soldering to aluminum The soldering is poor in wettability and has low solder joint strength and poor joint reliability. Moreover, although some have improved the strength by using zinc or special flux, even in that case, there is a problem in strength against the solder against the copper electrode.

(2) When the external electrode is fixed to the translucent airtight container by sticking, it may be peeled off from the translucent airtight container due to heat during soldering, and the external electrode is fixed and held to the translucent airtight container. The reliability of is poor. Further, the heat at the time of soldering is applied to the translucent airtight container itself as thermal stress, which may adversely affect the durability reliability of the fluorescent lamp.

(3) When soldering the tip of the external lead wire and one end of the external electrode, solder swells (protrusions) occur at the solder joint on the outer surface of the translucent airtight container. Therefore, in the covering mounting process of covering the translucent airtight container with the translucent insulating tube so as to cover the external electrode in order to mechanically protect the external electrode, the translucent insulating tube is used as the translucent airtight container. At the time of insertion, the translucent insulating tube is caught by the protrusions formed by the solder, and the smooth mounting operation is hindered, resulting in poor workability.

(4) A light-transmitting airtight container covered with a light-transmitting insulating tube may cause the light-transmitting insulating tube to float from the light-transmitting airtight container in the vicinity of the protrusion made of solder. Can be a factor.

  Therefore, the present invention was devised in view of the above problems, and the object of the present invention is to use solder (especially, solder containing zinc) in connecting an external lead wire and an external electrode provided with aluminum. It is an object of the present invention to provide a rare gas discharge tube using connection means which does not require a wide range of heating. As a result, a rare gas discharge tube having high joining reliability, durability reliability, electrical characteristics, and workability is realized in a discharge tube having a high reflectance of ultraviolet light emitted from the discharge tube.

  In order to solve the above-mentioned problem, the invention described in claim 1 of the present invention includes a glass bulb in which a rare gas is enclosed in an airtight internal space sealed at both ends to form a discharge chamber, and the crow A pair of external lead wires each having one end embedded in each of both end portions of the bulb without being exposed in the internal space and the other end extending outside the glass bulb, and the outer surfaces of the glass bulb A pair of external electrodes extending in parallel along the longitudinal direction of the glass bulb at opposing positions, and an ultraviolet light transmissive insulation inserted on the outer surface of the glass bulb so as to cover the pair of external electrodes A rare gas discharge tube that includes a tube and emits excimer light by dielectric barrier discharge, wherein each of the pair of external electrodes extends from a portion covered with the insulating tube to the outside of the insulating tube, and And it is characterized in that it is electrically connected outside to different external leads of the pair of external leads.

  The invention described in claim 2 of the present invention is characterized in that, in claim 1, joining of the external electrode and the external lead wire is performed by spot welding or laser irradiation.

  In addition, the invention described in claim 3 of the present invention is characterized in that, in claim 1 or 2, the glass bulb is provided with a phosphor layer over the entire inner surface. Is.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the external electrode has a substantially single shape before being extended to the outer surface of the glass bulb. It has an L-shape or a substantially T-shape, and is characterized in that one end portion of the L-shape or two end portions of the T-shape located in mutually facing directions are joined to the external lead wire. To do.

  The invention described in claim 5 of the present invention is any one of claims 1 to 4, wherein the external electrode contains aluminum.

  The rare gas discharge tube of the present invention is provided with a pair of external electrodes at opposite positions on the outer surface of a glass bulb having an airtight inner space sealed at both ends and filled with a rare gas as a discharge chamber, Insert an ultraviolet transmissive insulating tube on the outer surface of the glass bulb so as to cover the pair of external electrodes, and extend the portion of the pair of external electrodes covered by the insulating tube to the outside of the insulating tube. The outer lead wire is electrically joined to different external lead wires out of a pair of external lead wires extending from both ends of the glass bulb outside the insulating tube.

  As a result, the joint between the external electrode and the external lead wire is provided in a portion other than the outer portion of the glass bulb, so that no protrusions such as solder bulges are generated on the outer portion of the glass bulb. In the insertion process, a smooth mounting operation is possible, and good workability can be ensured.

  Further, since there is no protrusion such as a solder bulge on the outer side of the glass bulb, the entire insulating tube is tightly covered with the glass bulb, and the occurrence of creeping discharge is suppressed.

  In addition, since the joining process of the external electrode and the external lead wire can be the last process in the manufacturing process of the rare gas discharge tube, the process up to that point can be smoothly advanced and an external force can be applied during the joining work. A reliable joining state can be realized without being affected by the above.

It is front explanatory drawing of embodiment. Similarly, it is side explanatory drawing of embodiment. Similarly, it is a longitudinal cross-sectional explanatory drawing in alignment with the central-axis direction of embodiment. Similarly, it is a longitudinal cross-sectional explanatory drawing along a perpendicular direction to the central axis of embodiment. It is explanatory drawing of an external electrode. It is explanatory drawing of the joining method of an external electrode and an external lead wire. Similarly, it is explanatory drawing of the joining method of an external electrode and an external lead wire. Similarly, it is explanatory drawing of the joining method of an external electrode and an external lead wire. It is wiring drive explanatory drawing of embodiment. It is ultraviolet irradiation irradiation explanatory drawing. It is a spectrum distribution map of irradiation light. It is explanatory drawing of an external electrode. It is side surface explanatory drawing of other embodiment. It is explanatory drawing of the joining method of an external electrode and an external lead wire. Similarly, it is explanatory drawing of the joining method of an external electrode and an external lead wire. Similarly, it is explanatory drawing of the joining method of an external electrode and an external lead wire. Similarly, it is explanatory drawing of the joining method of an external electrode and an external lead wire. It is explanatory drawing of a prior art example.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. 1 to 17 (the same parts are denoted by the same reference numerals). The embodiments described below are preferable specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. Unless stated to the effect, the present invention is not limited to these embodiments.

  1 is a front explanatory view of an embodiment relating to a rare gas discharge tube of the present invention, FIG. 2 is a side explanatory view, FIG. 3 is a longitudinal sectional explanatory view along the central axis direction, and FIG. 4 is a longitudinal section along the vertical direction along the central axis. It is surface explanatory drawing.

  A rare gas discharge tube (hereinafter abbreviated as “discharge tube”) 1 according to the present embodiment includes a cylindrical glass bulb 2 made of glass that transmits ultraviolet rays, such as quartz glass. The glass chamber 2 is closed with a glass bead 3) and a discharge chamber 4 comprising an airtight space is provided in the glass bulb 2.

  A rare gas is hermetically sealed in the discharge chamber 4 as a sealed gas. Specifically, xenon gas or a mixed gas obtained by mixing xenon and a buffer gas such as neon, argon, and helium is used. The inside of the discharge chamber 4 in which the sealing gas is sealed is reduced to a pressure of 100 to 200 Torr.

A phosphor layer 5 having a uniform thickness is provided on the inner surface of the glass bulb 2 over the entire circumference. As the phosphor forming the phosphor layer 5, a fluorescent material that emits ultraviolet rays having a desired spectral distribution by being excited by vacuum ultraviolet rays having a peak wavelength of 172 nm obtained by excimer discharge is used in this embodiment. For example, LaPO ₄ : Pr is used.

  At both ends of the glass bulb 2, the respective one end portions 6a and 7a are embedded in the glass bead 3 without being exposed in the glass bulb 2, and the other end portions 6b and 7b are disposed in the longitudinal direction (axis line) of the glass bulb 2. A pair of external lead wires 6 and 7 are provided extending outward along the X direction.

  On the outer surface of the glass bulb 2, discharge electrode portions 8a and 9a of a pair of electrodes (external electrodes) 8 and 9 are extended in parallel along the longitudinal direction of the glass bulb 2 at positions facing each other. Extending portions 8b and 9b extending from the discharge electrode portions 8a and 9a in directions opposite to each other in the longitudinal direction of the glass bulb 2 are provided, and extending portions 8b and 9b are substantially perpendicular to each other from one side edge. Folded extensions 8c and 9c are provided which are bent to extend toward the pair of external lead wires 6 and 7.

  A leading end portion (hereinafter simply referred to as “tip portion”) 8e serving as a lead wire joint portion of the bent extension portion 8c is electrically joined to an external lead wire 6 extending outside the glass bead 3, A tip end portion (hereinafter simply referred to as “tip end portion”) 9 e serving as a lead wire joint portion of the bent extension portion 9 c is electrically joined to an external lead wire 7 extending outside the glass bead 3.

  The external electrodes 8, 9 are partially provided with an adhesive member such as an adhesive or an adhesive tape on a metal sheet made of gold, silver, copper, nickel, aluminum, etc., and discharge of the pair of external electrodes 8, 9 The electrode portions 8a and 9a are directly attached to the outer surface of the glass bulb 2 via an adhesive member.

  A metal sheet having a sheet thickness of 50 μm is used for the glass bulb 2 of the present embodiment having a tube diameter (outer diameter) of 4.8 mmφ. However, the thickness of the metal sheet is not necessarily limited to 50 μm, and is appropriately set according to the structural specifications or electrical specifications such as the tube diameter of the glass bulb 2 and the discharge voltage applied between the electrodes. .

  The outer portion of the glass bulb 2 has a high ultraviolet transmittance so as to cover the entire discharge electrode portions 8a and 9a of the pair of external electrodes 8 and 9 and the outer surface 2a of the glass bulb 2 other than the discharge electrode portions 8a and 9a. And a cylindrical insulating tube 10 having insulating properties and heat shrinkability.

  The insulating tube 10 is made of a tube (Teflon (registered trademark) tube) made of Teflon (registered trademark) in the present embodiment, and a pair of external electrodes 8 attached to the outer surface 2a of the glass bulb 2; Nine discharge electrode portions 8 a and 9 a are stuck and fixed in a state (pressed state) where the discharge electrode portions 8 a and 9 a are pressed against the outer surface 2 a of the glass bulb 2 by the contraction force of the heat-shrinkable insulating tube 10.

  The external electrodes 8 and 9 are manufactured by punching out an original sheet in which an adhesive member 21 such as an adhesive or an adhesive tape is partially disposed on a metal sheet 20 using a punching die. Used (see FIG. 5 (explanatory drawing of external electrodes)).

  The joining method of the tip 8e of the bending extension 8c of the external electrode 8 and the external lead 6 extending outside the glass bead 3 is as follows. First, the tip 8e of the bending extension 8c is wound around the external lead 6. (Refer to FIG. 6 (an explanatory diagram of a method for joining an external electrode and an external lead wire)).

  And the front-end | tip part 8e of the bending extension part 8c wound around the external lead wire 6 is clamped and hold | maintained with the welding electrodes 30 and 31 from both sides, and it supplies with electricity between the welding electrodes 30 and 31 in that state. The external lead wire 6 and the tip 8e are spot welded together (see FIG. 7 (an explanatory diagram of a method for joining the external electrode and the external lead wire)).

  Similarly, for the external electrode 9, the method for joining the distal end portion 9 e of the bending extension portion 9 c of the external electrode 9 and the external lead wire 7 extending outside the glass bead 3 is first performed by the distal end portion 9 e of the bending extension portion 9 c. Is wound around the external lead wire 7 (see FIG. 6).

  And the front-end | tip part 9e of the bending extension part 9c wound around the external lead wire 7 is clamped and held by the welding electrodes 30 and 31 from both sides, and it supplies with electricity between the welding electrodes 30 and 31 in that state. The external lead wire 7 and the tip 9e are spot welded together (see FIG. 7).

  When spot welding the external lead wire and the tip end of the external electrode, the method of holding the tip portion with respect to the external lead wire is a method of winding and holding the tip portion around the external lead wire as described above. For example, a plurality of slits are formed in each of the tip portions 8e and 9e to form a plurality of strips, and as shown in FIG. 8 (an explanatory diagram of a method for joining an external electrode and an external lead wire), The strip-shaped tip portions 8e and 9e are alternately distributed to both sides of the external lead wires 6 and 7, and are sandwiched and held by the welding electrodes 30 and 31 from both sides and energized between the welding electrodes 30 and 31. By doing so, it is also possible to spot weld the external lead wire 6 and the distal end portion 8e and the external lead 7 and the distal end portion 9e together.

  In spot welding, the method of holding the tip portion of the external electrode with respect to the external lead wire is not limited to the above two methods, and an appropriate method considering the workability of spot welding, the reliability of welding, etc. Is used. In that case, the tip is formed in an optimum shape so as to be compatible with the method.

  In the above embodiment, the external lead wire and the external electrode are joined by spot welding. However, the joining is not necessarily limited to spot welding, and a joining method such as laser irradiation or solder joining is also possible.

  FIG. 9 is an explanatory diagram of wiring drive when driving the discharge tube having the above-described configuration.

  In driving the discharge tube 1, a high frequency / high voltage of a rectangular wave or a pulse wave is applied to the pair of external lead wires 6 and 7. The frequency is preferably in the range of 40 kHz to 90 kHz, and the optimum voltage (peak voltage) varies depending on the diameter of the glass bulb 2.

  Then, the discharge is started between the external electrodes 8 and 9 through the dielectric glass bulb 2 and the discharge chamber 4, and the discharge gas (xenon gas) sealed in the discharge chamber 4 emits excimer light to generate vacuum ultraviolet rays (VUV). ).

  The vacuum ultraviolet rays are applied to the phosphor layer 5 provided on the inner surface of the glass bulb 2, and ultraviolet rays (UV) emitted from the phosphor layer 5 excited by the vacuum ultraviolet rays are emitted from the glass bulb 2 and the insulating tube 10 in the aperture region 40. Is transmitted to the outside (see FIG. 10 (ultraviolet ray irradiation explanatory diagram)).

  As shown in FIG. 11 (spectral distribution diagram), the ultraviolet rays irradiated to the outside are in the vicinity of 260 nm, which matches the spectral characteristics (sterilization line (UV-C)) of the sterilization action, which is the intended use of the discharge tube 1. 2 shows a spectral distribution having peaks of relative intensity at two locations near 240 nm on the shorter wavelength side.

  As described above, the rare gas discharge tube of the present invention is directly attached to the outer surface of the glass bulb, and the ultraviolet light is applied so as to cover the entire discharge electrode portion of the external electrode and the outer surface of the glass bulb other than the discharge electrode portion. One end of the portion of the external electrode that extends from the portion covered with the insulating tube is not exposed in the glass bulb. In this state, the other end of the pair of external lead wires embedded in the glass bead is electrically joined by spot welding.

  As a result, the bonding strength between the electrode including aluminum and the external lead wire is higher than that of the solder bonding.

  Further, when the external electrode and the external lead wire are joined, the glass bulb is not directly joined, and the durability reliability of the fluorescent lamp is not impaired.

  Moreover, since the joint part of an external electrode and an external lead wire is provided in parts other than the outer side part of a glass bulb, the protrusion like the rise of a solder does not arise in the outer side part of a glass bulb. Therefore, in the coating mounting process in which the glass bulb is covered with an insulating tube so as to cover the external electrode mechanically, there is no protrusion due to solder when the insulating tube is inserted into the glass bulb. Smooth mounting work is possible, and good workability can be ensured.

  Further, since there is no protrusion such as a solder bulge on the outer side of the glass bulb, the entire insulating tube is tightly covered with the glass bulb, and the occurrence of creeping discharge is suppressed.

  Further, after the insulating tube is mounted on the glass bulb so as to cover the external electrode, the external electrode and the external lead wire can be joined. Therefore, it becomes possible to make the joining process of an external electrode and an external lead wire the last process of the manufacturing process of a rare gas discharge tube. Therefore, the process up to that point can be smoothly performed, and a reliable joining state can be realized without being affected by external force during the joining operation.

  In the above-described embodiment, the external electrode punched into a substantially L shape is used, and the tip of the bent extended portion that is bent and extended from one side edge of the external electrode to the external lead wire is used as the external lead wire. Although the external electrodes 8 and 9 are bonded, as shown in FIG. 12 (explanation of external electrodes), an adhesive member 21 such as an adhesive or an adhesive tape is partially disposed on the metal sheet 20. It is also possible to use an original sheet that has been punched into a substantially T shape using a punching die.

  In this case, as shown in FIG. 13 (side view of the discharge tube), the discharge tube 1 has a pair of electrodes (external electrodes) 8 and 9 on the outer surface of the glass bulb 2 at positions facing each other. The portions 8a and 9a are extended in parallel along the longitudinal direction of the glass bulb 2, and extended from the discharge electrode portions 8a and 9a in directions opposite to each other in the longitudinal direction of the glass bulb 2. 8b and 9b are provided, of which the extension 8b is provided with bent extensions 8c and 8d that are bent at substantially right angles from both side edges and extended to the external lead wire 6 side.

  Tip portions (hereinafter simply referred to as “tip portions”) 8e and 8f, which serve as lead wire joint portions of the bent extension portions 8c and 8d, are electrically connected to the external lead wires 6 extending outside the glass beads 3. It is joined to.

  The method of joining the distal end portions 8e, 8f of the bent extension portions 8c, 8d of the external electrode 8 and the external lead wire 6 extended outside the glass bead 3 is as follows. First, the distal end portion 8e of the bent extension portion 8c is connected to the external lead. It is wound around the wire 6 (see FIG. 14 (an explanatory diagram of a method for joining an external electrode and an external lead wire)).

  Then, the tip 8f of the bent extension 8d is overlapped and wound on the tip 8e of the bent extension 8c wound around the external lead 6, and the overlapped portion is sandwiched between the welding electrodes 30 and 31 from both sides. The external lead wire 6 and the tip end portions 8e and 8f are spot welded integrally by energizing between the welding electrodes 30 and 31 in this state (see FIG. 15 (Fig. 15 (Method of joining external electrodes and external lead wires)). Refer to the explanatory diagram).

  The bent portions 9c and 9d that are bent at substantially right angles from both side edges of the extended portion 9b of the electrode (external electrode) 9 and extend toward the external lead wire 7 are described above. Since the configuration is the same as that of the bent extension portions 8c and 8d that are bent at substantially right angles from both side edges of the extension portion 8b and extended to the external lead wire 6 side, description thereof will be omitted.

  In this way, the external electrode is punched into a substantially T shape, and the respective distal ends of the two bent extensions are joined to the external lead wire, so that the external electrode is punched into a substantially L shape. The electrical connection between the external lead wire and the external electrode can be made more reliable than when the tip of the curved extension portion is joined to the external lead wire.

  When spot welding the external lead wire and the tip end of the external electrode, the method of holding the tip portion with respect to the external lead wire is a method of winding and holding the tip portion around the external lead wire as described above. For example, as shown in FIG. 16 (explanation of the joining method of the external electrode and the external lead wire), one side edge is formed on each of the two tip portions (8e, 8f) and (9e, 9f). By providing slits 50 and 51 extending from one side to the other side to the center, and fitting the slits 50 and 51 together as shown in FIG. 17 (explanation of the method of joining the external electrode and external lead wire) With the two tip portions (8e, 8f) and (9e, 9f) intersecting, the external lead wires are sandwiched between the welding electrodes 30 and 31 from both sides, held under pressure, and energized between the welding electrodes 30 and 31. And spot welding together Rukoto is also possible.

  At the time of spot welding, the method of superposing and holding the two tip portions with respect to the external lead wire is not limited to the above-mentioned two methods, but is appropriate in consideration of the workability of spot welding, the reliability of welding, and the like. The method is used. In that case, the two tip portions are formed in an optimum shape so as to be compatible with the method.

  The glass bulb is not necessarily provided with a phosphor layer on the inner surface. Whether the phosphor layer is not provided, or even if the phosphor layer is provided, what kind of phosphor is used for the phosphor layer is determined in consideration of the spectral characteristics of the desired irradiation light.

DESCRIPTION OF SYMBOLS 1 ... Noble gas discharge tube 2 ... Glass bulb 2a ... Outer side surface 3 ... Glass bead 4 ... Discharge chamber 5 ... Phosphor layer 6 ... External lead wire 6a ... One end part 6b ... Other end part 7 ... External lead wire 7a ... One end part 7b ... the other end 8 ... electrode (external electrode)
8a ... Discharge electrode part 8b ... Extension part 8c ... Bending extension part 8d ... Bending extension part
8e ... Tip (lead wire joint)
8f ... Tip (lead wire joint)
9 ... Electrode (External electrode)
9a ... Discharge electrode part 9b ... Extension part 9c ... Bending extension part 9d ... Bending extension part
9e ... Tip (lead wire joint)
9f ... Tip (lead wire joint)
DESCRIPTION OF SYMBOLS 10 ... Insulating tube 20 ... Metal sheet 21 ... Adhesive member 30 ... Welding electrode 31 ... Welding electrode 40 ... Aperture area | region 50 ... Slit 51 ... Slit

Claims (5)

A glass bulb in which a rare gas is sealed in an airtight internal space sealed at both ends to form a discharge chamber;
A pair of external lead wires embedded in each end of the crow bulb with one end not exposed in the internal space and the other end extended outside the glass bulb;
A pair of external electrodes extending parallel to each other on the outer surface of the glass bulb along the longitudinal direction of the glass bulb;
An ultraviolet transmissive insulating tube inserted on the outer surface of the glass bulb so as to cover the pair of external electrodes;
A rare gas discharge tube that emits excimer light by dielectric barrier discharge,
Each of the pair of external electrodes extends outside the insulating tube from a portion covered with the insulating tube, and is electrically joined to different external lead wires of the pair of external lead wires outside the insulating tube. A rare gas discharge tube.   The rare gas discharge tube according to claim 1, wherein the external electrode and the external lead wire are joined by spot welding or laser irradiation.   The rare gas discharge tube according to claim 1 or 2, wherein the glass bulb is provided with a phosphor layer over the entire circumference of the inner surface.   The external electrode has a substantially L-shape or a substantially T-shape before being extended to the outer surface of the glass bulb, and one end portion of the L-shape or a T-shape each other. The rare gas discharge tube according to any one of claims 1 to 3, wherein two end portions located in opposite directions are joined to the external lead wire.   The rare gas discharge tube according to claim 1, wherein the external electrode contains aluminum.

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