JP2005078922A - Indirectly heated electrode for gas discharge tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an indirectly heated electrode for a gas discharge tube, which is excellent in productivity, and surely supports a coil member. <P>SOLUTION: This indirectly heated electrode C1 for the gas discharge tube has a heater 1, a double coil 3, a linear member 5, a metal oxide 7, and a plate-shaped member 9. An electric insulating layer 2 is formed on the surface of the heating heater 1. The heater 1 is disposed in the inside of the double coil 3 by being inserted in it. The linear member 5 is disposed throughout the longitudinal direction of the double coil 3. The metal oxide 7 is held by the double coil 3, and is provided so as to be brought into contact with the linear member 5. One end of the heater 1, one end of the double coil 3, and both ends of the linear member 5 are bonded to the plate-shaped member 9 by welding. Thereby, the plate-shaped member 9, the heater 1, the double coil 3, and the linear member 5 are conducted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an indirectly heated electrode for a gas discharge tube.

As this type of indirectly heated electrode for a gas discharge tube, a coil member wound in a coil shape, a heater disposed inside the coil member, and an outer side of the coil member are arranged in the longitudinal direction of the coil member. One having a linear refractory metal provided and a metal oxide as an easy-electron emitting material held by a coil member is known (for example, see Patent Document 1).
International Publication WO02 / 49070 Pamphlet

  However, in the indirectly heated electrode for a gas discharge tube disclosed in Patent Document 1, the end of a linear refractory metal is welded to a round rod-shaped lead rod, and the coil member is interposed via the linear refractory metal. It is configured to be supported by a lead rod, and the structure disclosed in Patent Document 1 is difficult to say that the linear refractory metal and the lead rod can be fixed reliably and easily. Moreover, the support of the coil member is unstable.

  This invention is made | formed in view of the above-mentioned point, and makes it a subject to provide the indirectly heated electrode for gas discharge tubes which is excellent in manufacturability and can support a coil member reliably.

  An indirectly heated electrode for a gas discharge tube according to the present invention is an indirectly heated electrode for a gas discharge tube used in a gas discharge tube in which a gas is hermetically sealed in a sealed container, and a coil member wound in a coil shape, A heater for heating disposed on the inside of the coil member and having an electrically insulating layer formed on the surface thereof, a metal oxide as an electron emission material held by the coil member, and a longitudinal direction of the coil member. And a linear electric conductor in electrical contact with the coil member, and a plate-like electric conductor to which at least one end of the linear electric conductor and one end of the coil member are joined.

  In the indirectly heated electrode for a gas discharge tube according to the present invention, at least one end of the linear electrical conductor and one end of the coil member are joined to the same plate-shaped electrical conductor, so that the linear electrical conductor and the coil member are joined. And the plate-like electric conductor can be reliably and easily fixed, and the coil member can be reliably supported. In addition, handling of the electrode intermediate body having a configuration in which the linear electric conductor and the coil member are joined to the plate-like electric conductor (for example, conveyance during the manufacturing process) is facilitated.

  Moreover, it is preferable that one end of the heater for heating is joined to the plate-like electric conductor. When configured in this way, one end of the heating heater is also joined to the plate-like electrical conductor to which the linear electrical conductor and the heater for heating are joined, and the heating heater and the plate-like electrical conductor are fixed. In addition, the heating heater can be reliably and easily supported.

  In addition, it is preferable that a stem pin standing on a stem constituting the end portion of the sealed container is joined to the plate-shaped electric conductor. When comprised in this way, the said electrode intermediate body can be joined to a stem pin reliably and easily.

  Moreover, it is preferable that the linear electric conductor is bent in the middle thereof, and both ends of the linear electric conductor are joined to the plate-like electric conductor. When comprised in this way, the joint strength to the plate-shaped electric conductor of a linear electric conductor can be raised.

  The “plate shape” used in this specification includes shapes such as a ribbon shape and a foil shape.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in manufacturability and can provide the indirectly heated electrode for gas discharge tubes which can support a coil member reliably.

  Hereinafter, preferred embodiments of an indirectly heated electrode for a gas discharge tube according to the present invention will be described in detail with reference to the drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  FIG. 1 is a perspective view of an indirectly heated electrode for a gas discharge tube according to this embodiment, and FIG. 2 is a schematic sectional view of the indirectly heated electrode for a gas discharge tube according to this embodiment. Moreover, in this embodiment, the example which applied the indirectly heated electrode for gas discharge tubes to the cathode (an indirectly heated cathode for gas discharge tubes) is shown.

  As shown in FIGS. 1 and 2, the indirectly heated electrode C1 for a gas discharge tube includes a heater 1, a double coil 3 as a coil member, a linear member 5 as a linear electric conductor, It has a metal oxide 7 as an easy-electron emitting material (cathode material) and a plate-like member 9 as a plate-like (including ribbon-like and foil-like) electric conductor.

The heater 1 is composed of a filament coil in which a tungsten wire having a diameter of 0.1 to 0.5 mm, for example, 0.28 mm, is wound twice. The surface of the tungsten filament coil is electrically charged by an electrodeposition method or the like. An electrically insulating layer 2 is formed by covering with an insulating material (for example, alumina, zirconia, magnesia, silica, etc.). A cylindrical pipe made of an electric insulating material (for example, alumina, zirconia, magnesia, silica, etc.) is used instead of the electric insulating layer 2, and the heating heater 1 is inserted into the cylindrical pipe to insulate the heating heater 1. A configuration may be adopted. Here, the double coil 3 and the metal oxide 7 as the electron-emitting material constitute an electron emission part that receives heat from the heater 1 and emits electrons.

  The double coil 3 is a multiple coil composed of coils wound in a coil shape, and a tungsten wire having a diameter of 0.0913 mm is wound around a primary mandrel 4 having an outer diameter of 1.1 mm at a pitch of 0.13 mm. A primary coil (outer diameter of 1.283 mm) is rotated to form a double coil by winding the primary coil around a secondary mandrel with an outer diameter of 5.8 mm at a pitch of 1.5 mm, for example, 9 times. is there. Inside the double coil 3, a heater 1 is inserted and disposed.

  The double coil 3 is used in a state in which the secondary mandrel is removed and the primary mandrel 4 is left, and the primary mandrel 4 is provided. The primary mandrel 4 is made of, for example, molybdenum. In addition, the double coil 3 has a plurality of wound coil portions having a predetermined interval (0.1 mm to 0.3 mm). Here, the mandrel is a core wire that plays the role of a mold that determines the winding diameter when creating the filament coil.

  As the coil member, a triple coil or a single coil may be used instead of the double coil 3. Thus, by using a coil-shaped member, the contact area as a holding means for holding the metal oxide 7 as the electron-emitting material can be increased.

  The linear member 5 is a rigid body (metal conductor) having conductivity, belonging to groups IIIa to VIIa, VIII, and Ib of the periodic table, specifically tungsten, tantalum, molybdenum, rhenium, niobium, osmium, iridium, It consists of a single metal of a high melting point metal (melting point 1000 ° C. or higher) such as iron, nickel, cobalt, titanium, zirconium, manganese, chromium, vanadium, rhodium, rare earth metal, or an alloy thereof. In this embodiment, a linear member made of tungsten is used. The diameter of the linear member 5 is set to about 0.1 mm. The linear member 5 has a predetermined length, and is disposed outside and inside the double coil 3 so as to be substantially orthogonal to the discharge direction over the longitudinal direction of the double coil 3. As shown in FIG. 2, the linear member 5 is provided in electrical contact with a plurality of coil portions of the double coil 3 along the longitudinal direction of the double coil 3. Preferably, the double coil 3 is provided in electrical contact over the entire length in the longitudinal direction. This linear member 5 is provided in the outermost surface side part of the electron emission part containing the double coil 3 and the metal oxide 7 as an electron emission substance.

  The indirectly heated electrode C1 has a metal oxide 7 as an electron-emitting material. The metal oxide 7 is held by the double coil 3 and is provided in contact with the linear member 5. The metal oxide 7 and the linear member 5 are exposed to the outside of the indirectly heated electrode C1 so that the surface of the metal oxide 7 and the surface of the linear member 5 become a discharge surface. The linear member 5 comes into contact with the surface portion.

  As the metal oxide 7, any one of oxides of barium (Ba), strontium (Sr), calcium (Ca), a mixture of these oxides, or the main constituent elements are barium, strontium, calcium Among these, an oxide which is a single oxide or a mixture of these oxides and whose secondary constituent element is a rare earth metal (IIIa in the periodic table) containing a lanthanum series is used. Barium, strontium, and calcium have a small work function, can easily release thermionic electrons, and can increase the supply amount of thermionic electrons. Further, when a rare earth metal (IIIa in the periodic table) is added as a sub-constituent requirement, it is possible to further increase the supply amount of thermoelectrons and to improve the spatter resistance.

  The metal oxide 7 is obtained by applying a metal carbonate (for example, barium carbonate, strontium carbonate, calcium carbonate, etc.) as a cathode material, and subjecting the applied metal carbonate to thermal decomposition under vacuum. In addition, when performing vacuum thermal decomposition by energizing the heater for heating, AC thermal decomposition is preferable to direct current thermal decomposition. The metal oxide 7 thus obtained finally becomes an electron-emitting substance. The metal carbonate as the cathode material is composed of the linear member 5 in a state where the heater 1 is disposed inside the double coil 3 and the linear member 5 is disposed outside the double coil 3. It is applied from the side. The metal carbonate need not be applied so as to cover the entire circumference of the indirectly heated electrode C1 (double coil 3), and may be applied only to the portion where the linear member 5 is provided. .

  As shown in FIG. 2, the heater 1 is in contact with the metal oxide 7 through the electrical insulating layer 2. For this reason, the heat of the heater 1 can be reliably and efficiently transmitted to the metal oxide 7 during preheating. Further, compared with the indirectly heated cathode for gas discharge tubes disclosed in Japanese Examined Patent Publication No. 62-56628, a heat radiation area is reduced, which is necessary for hot cathode operation. The loss of heat can be suppressed. For this reason, it is possible to design the electrode to operate only by the amount of heat by self-heating, without requiring the supply of heat to the electrode from the outside and forced overheating. Here, self-heating means that when electrons are emitted from the electrode in the gas discharge tube, ionized gas molecules in the discharge space collide and are electrically neutralized, but due to the impact of the gas molecules colliding with the electrode, It means that heat is generated.

The plate-like member 9 is a conductive metal (metal conductor) and is made of a simple substance of an iron group metal such as iron, nickel, cobalt, or an alloy thereof. In the present embodiment, a nickel plate-like member is used. The thickness of the plate member 9 is set to about 0.2 μm, and the area of the plate member 9 is set to about 6 mm ² (2 mm × 3 mm). One end of the heater 1 for heating, one end of the double coil 3, and both ends of the linear member 5 are joined to the plate member 9 by welding or the like. Thereby, the plate-shaped member 9, the heater 1, the double coil 3, and the linear member 5 are in electrical contact and are in a conductive state. In addition, the linear member 5 should just be joined to the plate-shaped member 9 at least one end.

  Next, an example of a process for manufacturing the indirectly heated electrode C1 for a gas discharge tube having the above-described configuration will be described with reference to FIGS.

  First, as shown in FIG. 3, the linear member 5 is bent into a hairpin shape, and each end of the linear member 5 in a state of being bent into a hairpin shape is welded to the plate-like member 9. As shown in FIG. 4, the welding is performed by sandwiching the linear member 5 and the plate-like member 9 between the pair of welding electrodes 30 and 31 and energizing them. As the energization method, various methods such as direct current, alternating current, and pulse shape can be used.

  Next, as shown in FIG. 5, the bent portion 6 side of the linear member 5 bent into a hairpin shape is bent, and the bent linear member 5 is passed inside the double coil 3. 3 is inserted. Thereby, the linear member 5 is provided in electrical contact with the plurality of coil portions of the double coil 3 along the longitudinal direction of the double coil 3. Then, as shown in FIG. 5, the bent portion 6 of the linear member 5 and one end of the double coil 3 are welded to the plate-like member 9. In FIG. 5, each end of the linear member 5 is joined to one surface side of the plate-like member 9, and the bent portion 6 of the linear member 5 and one end of the double coil 3 are joined to the other surface side. However, the present invention is not limited to this. For example, each may be joined to the same surface side.

  Next, as shown in FIG. 6, one end of the heater 1 is welded to the plate member 9. By the way, the diameter of the tungsten strand which comprises the heater 1 for heating is thin, and when the end of the heater 1 for welding is welded to the plate-shaped member 9, there exists a possibility that the heater 1 for a heating may fracture | rupture. For this reason, in the present embodiment, a cylindrical member 13 made of metal (for example, nickel) is placed on one end of the heater 1 for heating, and is welded to the plate member 9 via the cylindrical member 13. . Thereby, the fracture | rupture of the heater 1 mentioned above can be prevented. The cylindrical member 13 may cover the electrical insulating layer 2 of the heater 1 for heating. Further, instead of using the cylindrical member 13, a metal (for example, nickel) plate-like (including ribbon-like or foil-like) member is used, and the plate-like member and the plate-like member 9 are used as a heater for heating. 1 may be welded with one end sandwiched therebetween.

  Through the above steps, an electrode intermediate body in which the heater 1, the double coil 3, and the linear member 5 are joined to the plate member 9 can be obtained. As described above, the indirectly heated electrode C1 having the metal oxide 7 is obtained by applying a metal carbonate to the electrode intermediate and subjecting the metal carbonate to vacuum heat decomposition.

  In order to further ensure electrical contact between the linear member 5 and the plurality of coil portions of the double coil 3, as shown in FIG. A portion where the heavy coil 3 is sandwiched may be sandwiched by tweezers or the like to form a throttle portion, and the linear member 5 and the double coil 3 may be pressed against each other. Further, as shown in FIG. 7B, the end of the linear member 5 is guided from the inside of the double coil 3 to the outside through the coil portion, and the linear member 5 and the double coil 3 are pressed against each other. Also good. Further, as shown in FIG. 7C, the end of the linear member 5 may be crossed once or a plurality of times, and the linear member 5 and the double coil 3 may be pressed.

  Further, the linear member 5 is bent from a linearly extended state as shown in FIG. 8 without being bent into a hairpin shape, and the bent portion is passed through the inside of the double coil 3 so that the double coil 3 is You may make it pinch | interpose. At this time, the end of the linear member 5 may be wound around the double coil 3 to integrate the linear member 5 and the double coil 3, and then welded to the plate member 9. Thereby, the linear member 5 and the double coil 3 can be press-contacted. Further, only one end of the linear member 5 wound around the double coil 3 may be welded to the plate-like member 9.

  Further, as shown in FIG. 9, after the bent portion 6 of the linear member 5 is hooked on the portion of the double coil 3 on the plate-like member 9 side and passed through the inside of the double coil 3, the linear member 5. The bent linear member 5 may be welded to the plate member 9 by sandwiching the double coil 3 through the outside of the double coil 3.

  Next, a gas discharge tube including the indirectly heated electrode C1 having the above-described configuration will be described with reference to FIG.

  As shown in FIG. 10, the gas discharge tube DT1 includes a tubular bulb 21 as a sealed container, first and second stem pins (introduction lines) 23 and 25, and a pair of indirectly heated electrodes C1. Yes. In FIG. 10, only one indirectly heated electrode C1 is illustrated.

  The tubular bulb 21 is made of a material such as glass, and includes a stem 22 that constitutes an end of the tubular bulb 21. The inside of the tubular bulb 21 is filled with a rare gas such as argon, or a rare gas such as argon and mercury. Further, a phosphor (not shown) is applied to the inner wall of the tubular bulb 21. The first and second stem pins 23 and 25 are erected on the stem 22 of the tubular valve 21 at both ends of the tubular valve 21 and extend in the tube axis direction. The indirectly heated electrode C <b> 1 is attached to the distal end portions of the first and second stem pins 23 and 25 so that the linear member 5 faces each other, and is hermetically sealed in the tubular valve 21.

  As shown in FIG. 11, the plate-like member 9 is joined to the first stem pin 23 by welding or the like, and is electrically connected to the first stem pin 23. The other end of the heater 1 is joined to the second stem pin 25 by welding or the like, and is electrically connected to the second stem pin 25. Note that the plate-like member 9 is not necessarily joined to the first stem pin 23, and the linear member 5 may be joined to the first stem pin 23.

  Further, as shown in FIG. 12, a converging cylinder 41 may be provided in front of the indirectly heated electrode C1 (between the oppositely heated electrode). The converging cylinder 41 is electrically connected to the first stem pin 23 through the plate-like member 9 or the like. Before the electrons emitted from the opposite indirectly heated electrode C1 reach the indirectly heated electrode C1, the electrons are captured by the converging cylinder 41 located in front of the indirectly heated electrode C1 and are distributed. Thereby, the convergence current density to the indirectly heated electrode C1 main body accompanying the electron convergence in an anode operation state can be reduced, and damage to the indirectly heated electrode C1 can be reduced.

  As described above, in the present embodiment, at least one end of the linear member 5 and one end of the double coil 3 are joined to the same plate member 9, and the linear member 5 and the double coil 3 The plate-like member 9 can be fixed securely and easily, and the plate-like member 9 can be reliably supported. In addition, it is easy to handle an electrode intermediate having a configuration in which the linear member 5 and the double coil 3 are joined to the plate member 9 (for example, conveyance in the middle of the manufacturing process, application of metal carbonate and vacuum thermal decomposition). Become.

  In the present embodiment, one end of the heater 1 is joined to the plate-like member 9. Thereby, one end of the heater 1 is also joined to the plate-like member 9 to which the linear member 5 and the double coil 3 are joined, and the fixing of the heater 1 and the plate-like member 9 is surely and easily performed. The heater 1 for heating can be reliably supported.

  In the present embodiment, the plate member 9 is joined with a first stem pin 23 erected on a stem 22 constituting the end of the tubular valve 21. When configured in this manner, the electrode intermediate can be reliably and easily joined to the first stem pin 23.

In the present embodiment, the linear member 5 is bent at an intermediate position, and both ends of the linear member 5 are joined to the plate member 9. Thereby, the joint strength to the plate-shaped member 9 of the linear member 5 can be raised.

  The present invention is not limited to the embodiment described above. For example, although a refractory metal is used as the linear member 5, a thin porous metal is used instead of the refractory metal as long as it is conductive and has a rigid body whose melting point is higher than the operating temperature of the cathode. Carbon fiber or the like may be used. Further, nitride or carbide such as tantalum, titanium, niobium or the like is applied to the surface of the metal oxide 7, the double coil 3, or the linear member 5 in order to improve the sputtering resistance and discharge performance of the metal oxide 7. You may make it adhere.

  Moreover, in this embodiment, although the surface of the linear member 5 is exposed, it is not necessary to expose these, if the linear member 5 is contacting the metal oxide 7, The surface of the linear member 5 may be covered with the metal oxide 7.

It is a schematic perspective view which shows the indirectly heated electrode for gas discharge tubes which concerns on this embodiment. It is a schematic sectional drawing which shows the indirectly heated electrode for gas discharge tubes which concerns on this embodiment. It is a figure for demonstrating an example of the manufacturing process in the indirectly heated electrode for gas discharge tubes which concerns on this embodiment. It is a figure for demonstrating an example of the manufacturing process in the indirectly heated electrode for gas discharge tubes which concerns on this embodiment. It is a figure for demonstrating an example of the manufacturing process in the indirectly heated electrode for gas discharge tubes which concerns on this embodiment. It is a figure for demonstrating an example of the manufacturing process in the indirectly heated electrode for gas discharge tubes which concerns on this embodiment. (A)-(c) is a figure for demonstrating an example of the manufacturing process in the indirectly heated electrode for gas discharge tubes which concerns on this embodiment. It is a figure for demonstrating an example of the manufacturing process in the indirectly heated electrode for gas discharge tubes which concerns on this embodiment. It is a figure for demonstrating an example of the manufacturing process in the indirectly heated electrode for gas discharge tubes which concerns on this embodiment. It is a schematic perspective view which shows the gas discharge tube provided with the indirectly heated electrode for gas discharge tubes which concerns on this embodiment. It is a schematic perspective view which shows the indirectly heated electrode for gas discharge tubes and the 1st stem pin in the gas discharge tube shown by FIG. It is a schematic perspective view which shows the modification of the gas discharge tube shown by FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Heating heater, 2 ... Electrical insulation layer, 3 ... Double coil, 5 ... Linear member, 7 ... Metal oxide, 9 ... Plate-shaped member, 13 ... Cylindrical member, 21 ... Tubular valve, 22 ... Stem 23 ... 1st stem pin, 25 ... 2nd stem pin, C1 ... indirectly heated electrode for gas discharge tube, DT1 ... gas discharge tube.

Claims (4)

An indirectly heated electrode for a gas discharge tube used for a gas discharge tube in which gas is hermetically sealed in a sealed container,
A coil member wound in a coil shape;
A heater for heating disposed on the inside of the coil member and having an electrically insulating layer formed on the surface;
A metal oxide as an electron emission material held by the coil member;
A linear electrical conductor disposed over the longitudinal direction of the coil member and in electrical contact with the coil member;
An indirectly heated electrode for a gas discharge tube, comprising: a plate-like electric conductor to which at least one end of the linear electric conductor and one end of the coil member are joined.   The indirectly heated electrode for a gas discharge tube according to claim 1, wherein one end of the heater for heating is joined to the plate-like electric conductor.   The indirectly heated electrode for a gas discharge tube according to claim 1, wherein a stem pin erected on a stem constituting an end of the sealed container is joined to the plate-like electric conductor.   2. The gas discharge tube according to claim 1, wherein the linear electrical conductor is bent at an intermediate position thereof, and both ends of the linear electrical conductor are joined to the plate-shaped electrical conductor. Side-heated electrode.

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