JP4054017B2 - Gas discharge tube - Google Patents

Description

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

As an indirectly heated electrode used in this type of gas discharge tube, for example, an electrode disclosed in Japanese Patent Publication No. 62-56628 (US Pat. No. 4441048) is known. The indirectly heated electrode for gas discharge tubes (indirectly heated cathode for gas discharge tubes) disclosed in Japanese Patent Publication No. 62-56628 is tightly fixed by winding a double coil around the outer wall of a thermally conductive cylinder. A paste-like cathode material is applied inside and between the secondary spirals of the double coil to form a uniform cathode surface on the cylindrical surface, and a heater is provided inside the cylinder. .
Japanese Examined Patent Publication No. Sho 62-56628 (US Pat. No. 4441048)

  An object of the present invention is to provide a gas discharge tube capable of extending the life of an electrode and obtaining a stable discharge.

  As a result of research, the present inventors have newly found the following facts. When the potential distribution on the electrode (cathode) surface is non-uniform, the amount of heat generated is also non-uniform, so the generation density of thermoelectrons is also non-uniform and local discharge (distribution of the discharge position) occurs. become. Then, the local discharge causes the cathode material (metal oxide) to be scraped off (sputtering), stabilized by oxidation with a reduced metal (mineralization), that is, the thermoelectron emission ability is lowered, and the discharge position is next. Move to a position with good thermionic emission characteristics. Thus, the electrode surface is deteriorated while repeating local thermionic emission deterioration. Further, the discharge itself becomes unstable due to the movement of the discharge position described above.

  Based on such research results, the gas discharge tube according to the present invention is a gas discharge tube comprising a sealed container and a pair of indirectly heated electrodes provided inside the sealed container, and a pair of indirectly heated types The electrode includes a coil member wound in a coil shape, a heating heater disposed on the inside of the coil member, and an electric insulating layer formed on the surface thereof, and an easy-electron emitting material held on the coil member It has a metal oxide and an electric conductor provided in contact with the coil member inside the coil member and having a predetermined length.

  In the gas discharge tube according to the present invention, the equipotential surface is effectively formed on the back surface (surface opposite to the discharge surface) of the coil member by the electric conductor in each of the pair of indirectly heated electrodes. Thermionic emission occurs in a wide region of the equipotential surface, the discharge area increases, the amount of electron emission per unit area (electron emission density) increases, and the load at the discharge position is reduced. Thereby, generation | occurrence | production of local discharge can be suppressed and the lifetime improvement of an electrode can be achieved. Further, since the movement of the discharge position is also suppressed, a stable discharge can be obtained for a long time. In addition, in relation to the increase in the discharge area, the current density is slightly increased to slightly increase the load, that is, even if the discharge current is increased, the damage can be reduced compared to the conventional one, and is almost the same as the conventional one. With the shape, an indirectly heated electrode with a large discharge current can be provided, and a pulse operation and a large current operation can be realized.

  In addition, the electrical conductor is preferably provided in contact with the metal oxide and in contact with a plurality of coil portions of the coil member. When configured in this way, the electrical conductors make the discharge surface potential consisting of a plurality of discharge points or discharge lines approximately equal, and stabilization due to spattering of metal oxides, which are degradation factors, and oxidation with reduced metals (mineralization) ), That is, the decrease in thermionic emission ability can be suppressed, and the movement of the discharge position can also be suppressed. As a result, the life of the electrode and stable discharge can be obtained with a simple configuration in which the electric conductor is provided in contact with the metal oxide.

  The electric conductor is preferably a refractory metal formed in a mesh shape, a linear shape or a plate shape. Thus, since the electrical conductor is a refractory metal formed in a mesh shape, a linear shape, or a plate shape, an electrical conductor having a configuration capable of suppressing a decrease in thermionic emission ability and a movement of the discharge position can be obtained at low cost and. This can be realized even more easily. Further, since the electric conductor is a rigid body, it is easy to process and can be provided in close contact with the metal oxide. The “plate shape” used in the present application includes shapes such as a ribbon shape and a foil shape.

  Moreover, it is preferable that a coil member is a multiple coil comprised by winding the coil which has a mandrel in the shape of a coil. When configured in this way, by using multiple coils, the metal oxide, which is an electron-emitting substance, is sandwiched and held between the pitches (center distances), which is the distance between the wires forming the coil. Become. Thereby, since the distance between each pitch is as small as a gap, it is possible to suppress the metal oxide from falling off due to vibration. In addition, since there are a large number of gap structure pitches, a large amount of metal oxide can be retained, and there is an effect of replenishing the lost metal oxide content accompanying deterioration with time during discharge. Further, since the mandrel is provided, deformation of the multiple coil during processing can be suppressed.

  Further, the metal oxide may contain any single oxide of barium (Ba), strontium (Sr), and calcium (Ca), a mixture of these oxides, or an oxide of rare earth metal. preferable. As described above, since the metal oxide includes any one of barium, strontium, and calcium, or a mixture of these oxides or an oxide of a rare earth metal, the work function in the electron emission portion is reduced. It becomes possible to reduce the size effectively, and thermionic emission becomes easy.

  A gas discharge tube according to the present invention is a gas discharge tube comprising a sealed container and a pair of indirectly heated electrodes provided inside the sealed container, and the pair of indirectly heated electrodes have a mandrel. A coil member wound in a coil shape, a heating heater disposed on the inside of the coil member and having an electric insulating layer formed on the surface thereof, and the length of the coil member between the coil member and the heating heater Each having a high melting point metal disposed in a direction and formed in a mesh shape, a linear shape or a plate shape, and a metal oxide as an easy electron emitting material provided in contact with the coil member. The melting point metal is in electrical contact with the coil member at a plurality of locations.

  In the gas discharge tube according to the present invention, in each of the pair of indirectly heated electrodes, the back surface of the coil member (the surface opposite to the discharge surface) is equipotential on the electrode surface by the refractory metal and the inner portion of the coil member. Since the surface is effectively formed, thermionic emission occurs in a wide area of the formed equipotential surface, so the discharge area increases, the amount of electron emission per unit area (electron emission density) increases, and the discharge The load at the position will be reduced. As a result, it is possible to suppress metal oxide sputtering, which is a deterioration factor, and stabilization (mineralization) due to oxidation with a reduced metal, that is, a decrease in thermionic emission ability, thereby extending the life of the electrode. . Further, since the movement of the discharge position is also suppressed, a stable discharge can be obtained for a long time. Since the mandrel is provided, deformation of the coil member during processing can be suppressed. In addition, in relation to the increase in the discharge area, the current density is slightly increased to slightly increase the load, that is, even if the discharge current is increased, the damage can be reduced compared to the conventional one, and is almost the same as the conventional one. With the shape, an indirectly heated electrode with a large discharge current can be provided, and a pulse operation and a large current operation can be realized.

  Moreover, it is preferable that a coil member is the multiple coil comprised by winding a coil in coil shape. When comprised in this way, the metal oxide which is an electron emission substance will be pinched | interposed and hold | maintained between the pitches (center distance) which is the space | interval between the wire materials which form a coil. Thereby, since the distance between each pitch is as small as a gap, it is possible to suppress the metal oxide from falling off due to vibration. In addition, since there are a large number of gap structure pitches, a large amount of metal oxide can be retained, and there is an effect of replenishing the lost metal oxide content accompanying deterioration with time during discharge.

  Moreover, it is preferable that a rare gas or a rare gas and mercury are enclosed in a sealed container, and it is preferable that a phosphor film is formed on the inner surface of the sealed container. In addition, AC driving is preferable.

  ADVANTAGE OF THE INVENTION According to this invention, the gas discharge tube which can prolong the lifetime of an electrode and can obtain the stable discharge can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying 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.

(First embodiment)
FIG. 1 is a schematic front view of an indirectly heated cathode for a gas discharge tube according to the first embodiment, and FIG. 2 is a schematic side view of the indirectly heated cathode for a gas discharge tube according to the first embodiment. 3 is a schematic top view of the indirectly heated cathode for the gas discharge tube according to the first embodiment, and FIG. 4 is a schematic sectional view of the indirectly heated cathode for the gas discharge tube according to the first embodiment. 1 to 3 omit illustration of the electrical insulating layer 4 and the metal oxide 10 for the sake of explanation. 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 to 4, the indirectly heated cathode C1 for a gas discharge tube includes a heater 1, a double coil 2 as a coil member, a plate member 3 as an electric conductor, and easy electron emission. And a metal oxide 10 as a material (cathode material). The heater 1 is composed of a filament coil in which a tungsten wire having a diameter of 0.03 to 0.1 mm, for example, 0.07 mm, is wound twice. The surface of the tungsten filament coil is electrically coated by an electrodeposition method or the like. An insulating material (for example, alumina, zirconia, magnesia, silica, etc.) is coated to form the electrical insulating layer 4. A cylindrical pipe made of an electric insulating material (for example, alumina, zirconia, magnesia, silica, etc.) is used instead of the electric insulating layer 4, and the heating heater 1 is inserted into the cylindrical pipe to insulate the heating heater 1. A configuration may be adopted.

  The double coil 2 is a multiple coil composed of coils wound in a coil shape, and a tungsten wire having a diameter of 0.091 mm is formed as a primary coil having a diameter of 0.25 mm and a pitch of 0.146 mm. The primary coil is formed into a double coil having a diameter of 1.7 mm and a pitch of 0.6 mm. Inside the double coil 2, a heater 1 for heating is inserted and disposed. As the coil member, a triple coil or the like may be used instead of using the double coil 2.

  The plate-like member 3 formed into a plate shape 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, iron, nickel, cobalt, titanium, zirconium, manganese, chromium, vanadium, rhodium, a rare earth metal or other high-melting point metal (melting point of 1000 ° C. or higher), or an alloy thereof. In this embodiment, a plate member made of tungsten having a width of 1.5 mm and a thickness of 25.4 μm is used.

  The plate-like member 3 is provided on the inner side of the double coil 2 (between the heater 1 and the double coil 2) over the longitudinal direction of the double coil 2 and substantially orthogonal to the discharge direction. The plate-like member 3 is in a state of being electrically connected to the double coil 2. The plate-like member 3 is in contact with a plurality of coil portions inside the double coil 2 and forms a plurality of contacts with the double coil 2. The plate-like member 3 is grounded (GND) by being connected to a ground-side terminal of the heater 1 for heating. When the plate-like member 3 is grounded, the double coil 2 is also grounded. Instead of using the plate-like member 3, a linear member (for example, a tungsten strand having a diameter of about 0.1 mm) may be used. Moreover, you may weld each contact point of the plate-shaped member 3 and the double coil 2. FIG.

  The metal oxide 10 is held by the double coil 2 and the heater 1 and is provided in contact with the plate member 3. The surface of the metal oxide 10 and the surface of the double coil 2 are exposed outside the indirectly heated cathode C1 for the gas discharge tube, and the surface portion of the double coil 2 is in contact with the surface portion of the metal oxide 10. It has become.

  As the metal oxide 10, any single oxide 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 10 is obtained by applying a metal carbonate (for example, barium carbonate, strontium carbonate, calcium carbonate, etc.) as a cathode material and vacuum-decomposing the applied metal carbonate. In addition, when performing vacuum thermal decomposition by energizing the heater 1 for heating, the AC thermal decomposition is preferable to the direct current thermal decomposition. The metal oxide 10 thus obtained finally becomes an electron-emitting substance. As shown in FIG. 1 to FIG. 3B, the metal carbonate as the cathode material is provided with the heater 1 for heating inside the double coil 2, and the double coil 2 on the discharge surface side. It is applied from the surface side of the double coil 2 in a state in which the plate-like member 3 is disposed on the inner side. The metal carbonate does not have to be applied so as to cover the entire circumference of the indirectly heated cathode C1 (double coil 2) for the gas discharge tube, and the metal carbonate on the side where the plate-like member 3 serving as the discharge surface side is provided. You may make it apply | coat only to a part.

  As shown in FIGS. 3B and 4, the heater 1 is in contact with the metal oxide 10 and the double coil 2 through the electrical insulating layer 4. For this reason, the heat of the heater 1 can be reliably and efficiently transmitted to the metal oxide 10 and the double coil 2 during preheating. In addition, the loss of the amount of heat required for hot cathode operation is suppressed as compared with a gas discharge tube indirectly heated cathode disclosed in Japanese Examined Patent Publication No. 62-56628, which has a thermally conductive cylinder. be able to. 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.

  In addition to the above metal oxides, it is conceivable to use metal borides such as lanthanum boride, metal carbides, metal nitrides, etc. as the source of thermionic electrons, but these metal borides, metal carbides, metal Nitride and the like have a poor track record as a thermoelectron supply source as a hot cathode for a gas discharge tube, and there is no meaning to add as a main sub-component. However, it may be used in the peripheral part of the cathode for the effect other than the thermoelectron supply source, for example, the improvement of the insulating effect for suppressing the heat dissipation amount other than the discharge part.

Here, let us consider the discharge in predetermined three discharge parts (referred to as 1A, 1B, 1C from the side closer to the ground (GND) as the electron supply source) on the surface of the double coil 2. Each discharge part 1A, 1B, 1C has the winding resistance R1A, R1B, R1C of the double coil 2 from the plate-like member 3. The amount of discharge current depends on the work function of the part,
I1A>I1B> I1C (1)
Assuming that the main discharge is generated in the discharge part 1A having the winding resistance R1A, heat generation (W) due to Joule heat expressed by the following equation (2) increases.
W = I1A ² × R1A (2)
The work function is lowered due to the temperature rise. As a result, most of the discharge gathers in the discharge portion 1A, increasing the concentration of the discharge, and the discharge distribution becomes a continuous mountainous distribution having gentle unevenness. The slope of the discharge distribution increases as the value of the winding resistance R1A increases. Conversely, when the value of the winding resistance R1A decreases, the discharge distribution increases in a wide and gentle mountain shape. It will converge to a continuous distribution.

  From the above, in the indirectly heated cathode C1 for gas discharge tube of the present embodiment, the plate member 3 is provided in contact with the metal oxide 10 and in contact with the double coil 2, so that the plate member 3 effectively forms an equipotential surface together with the inner portion of the double coil 2 on the back surface (the surface opposite to the discharge surface) of the double coil 2. That is, the plate-like member 3 and the inner portion of the double coil 2 are configured by a plurality of electrical wirings (conducting paths) and are not restricted so that current flows in a single direction. Therefore, the electrical resistance between the ends of the surface of the plate-like member 3 is remarkably small, the surface of the plate-like member 3 is almost equipotential, and the potential of the discharge surface consisting of a plurality of discharge points or discharge lines is almost equal. Will be equal. In other words, the plate-like member 3 forms a plurality of electric circuits capable of flowing a discharge current in a direction parallel to the discharge surface, that is, forms a plurality of discharge electron (emission) paths (equipotential circuits). Become.

  Therefore, in the indirectly heated cathode C1 for the gas discharge tube, an equipotential surface is effectively formed on the back surface (the surface opposite to the discharge surface) of the double coil 2 by the plate member 3 and the double coil 2. Therefore, thermionic emission occurs in a wide region of the formed equipotential surface, the discharge area increases, the amount of electron emission per unit area (electron emission density) increases, and the load at the discharge position is reduced. In other words, it is possible to suppress the deterioration (mineralization), that is, the decrease in thermionic emission ability, which is a deterioration factor by sputtering of the metal oxide 10 and oxidation with the reduced metal. As a result, the occurrence of local discharge can be suppressed and the life of the cathode can be extended. Further, since the movement of the discharge position is also suppressed, a stable discharge can be obtained for a long time. Further, since the discharge area increases, the operating voltage and the amount of generated heat of the indirectly heated cathode C1 for gas discharge tubes can be reduced.

  In the indirectly heated cathode C1 for a gas discharge tube, the current density is slightly increased and the load is slightly increased in relation to the increase in the discharge area. Damage can be reduced compared to. As a result, an indirectly heated cathode for a gas discharge tube with a large discharge current having almost the same shape as the conventional one can be provided, and a pulse operation and a large current operation can be realized.

  In addition, since the plate-like member 3 is used as the electric conductor, an electric conductor having a configuration capable of suppressing the decrease in the thermoelectron emission ability and the movement of the discharge position can be realized at a lower cost and more easily. Moreover, since the plate-like member 3 (electrical conductor) is a rigid body, it can be easily processed and can be provided in close contact with the metal oxide 10. Furthermore, many locations where the plate-like member 3 and the metal oxide 10 are in contact can be easily provided.

  Moreover, in the indirectly heated cathode C1 for gas discharge tubes of this embodiment, it arrange | positions so that the double coil 2 holding the metal oxide 10 may be surrounded on the outer side by making the heater 1 into a nucleus, and the double coil 2 By disposing the plate-like member 3 so as to be in contact with the metal oxide 10 inside, the vibration suppressing effect of the double coil 2 works, and the metal oxide 10 can be prevented from falling. In addition, a large amount of the metal oxide 10 is held between the pitches of the double coils 2, and there is an effect of supplementing the lost metal oxide content accompanying the deterioration with time during discharge.

(Second Embodiment)
FIG. 5 is a schematic cross-sectional view of an indirectly heated cathode for a gas discharge tube according to the second embodiment. The second embodiment is different from the first embodiment in that the double coil has a mandrel and the electrical conductor is a mesh member.

  As shown in FIG. 5, the indirectly heated cathode C2 for a gas discharge tube includes a heater 1, a double coil 41 as a coil member, a mesh-like member 21 as an electric conductor, and an electron emission material. Metal oxide 10.

  Similar to the double coil 2 in the first embodiment, the double coil 41 is a multiple coil composed of coils wound in a coil shape, and has a mandrel 42. The heater 1 is provided inside the double coil 41. 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 a material for the mandrel, for example, molybdenum is used.

  The mesh member 21 formed in a mesh shape 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, iron, nickel, cobalt, titanium, zirconium, manganese, chromium, vanadium, rhodium, a rare earth metal or other high-melting point metal (melting point of 1000 ° C. or higher), or an alloy thereof. In the present embodiment, a mesh member is used in which a tungsten strand having a diameter of 0.03 mm is knitted into a mesh shape. The mesh size in the mesh member 21 is 80 mesh. The mesh member 21 has a predetermined length.

  The mesh member 21 is provided on the inner side of the double coil 41 (between the heater 1 and the double coil 41) over the longitudinal direction of the double coil 41 and substantially orthogonal to the discharge direction. The mesh member 21 is in a state of being electrically connected to the double coil 41. The mesh member 21 is in contact with a plurality of coil portions inside the double coil 41 and forms a plurality of contacts with the double coil 41. The mesh member 21 is grounded (GND) by being connected to a ground-side terminal of the heater 1 for heating. When the mesh member 21 is grounded, the double coil 41 is also grounded.

  The metal oxide 10 is held by the double coil 41 and the heater 1 for heating. The surface portion of the double coil 41 and the metal oxide 10 are exposed to the outside of the indirectly heated cathode C2 for gas discharge tube so that the surface of the metal oxide 10 and the surface portion of the double coil 41 become discharge surfaces. The surface portion of the double coil 41 comes into contact with the surface portion of the metal oxide 10. The metal oxide 10 is provided in the same manner as in the first embodiment.

  As shown in FIG. 5, the heater 1 is in contact with the metal oxide 10 and the double coil 42 through the electrical insulating layer 4. For this reason, the heat of the heater 1 for heating can be reliably and efficiently transmitted to the metal oxide 10 and the double coil 42 during preheating. Further, as in the first embodiment, the loss of heat necessary for the hot cathode operation can be suppressed, the heat supply to the electrode from the outside, forced overheating is not required, and the electrode can be formed only by the heat by self-heating. Can be designed to work.

  From the above, in the indirectly heated cathode C2 for gas discharge tube according to the present embodiment, the mesh member 21 is provided in contact with the metal oxide 10 and in contact with the double coil 41. 21 effectively forms an equipotential surface on the back surface (surface opposite to the discharge surface) of the double coil 41. That is, the mesh-like member 21 is composed of a plurality of electrical wirings (conducting paths) and is not restricted so that current flows in a single direction. Therefore, the electrical resistance between the ends of the surface of the mesh-like member 21 is extremely small, and the surface of the mesh-like member 21 is almost equipotential, and the potential of the discharge surface composed of a plurality of discharge points or discharge lines is almost equal. Will be equal. In other words, the mesh-like member 21 forms a plurality of electric circuits capable of flowing a discharge current in a direction parallel to the discharge surface, that is, forms a plurality of discharge electron (emission) paths (equipotential circuits). Become.

  Therefore, in the indirectly heated cathode C2 for the gas discharge tube, the equipotential surface is effectively formed on the back surface (the surface opposite to the discharge surface) of the double coil 41 by the mesh member 21. Thermionic emission occurs in a wide area of the equipotential surface, the discharge area increases, the amount of electron emission per unit area (electron emission density) increases, and the load at the discharge position is reduced. It is possible to suppress the metal oxide 10 from being sputtered and stabilized (mineralized) by oxidation with the reduced metal, that is, the decrease in thermionic emission ability. As a result, the occurrence of local discharge can be suppressed and the life of the cathode can be extended. Further, since the movement of the discharge position is also suppressed, a stable discharge can be obtained for a long time. Moreover, since the discharge area increases, the operating voltage and the amount of generated heat of the indirectly heated cathode C2 for gas discharge tube can be reduced.

  Further, in the indirectly heated cathode C2 for gas discharge tubes, the current density is slightly increased and the load is slightly increased in relation to the increase in the discharge area. Damage can be reduced compared to. As a result, an indirectly heated cathode for a gas discharge tube with a large discharge current having almost the same shape as the conventional one can be provided, and a pulse operation and a large current operation can be realized.

  Moreover, since the mesh-like member 21 is used as the electric conductor, an electric conductor having a configuration capable of suppressing the decrease in thermionic emission ability and the movement of the discharge position can be realized at a lower cost and more easily. Further, since the mesh-like member 21 (electrical conductor) is a rigid body, it is easy to process and can be provided in close contact with the metal oxide 10. Furthermore, many locations where the mesh-like member 21 and the metal oxide 10 are in contact can be easily provided.

Moreover, in the indirectly heated cathode C2 for gas discharge tube of this embodiment, it arrange | positions so that the double coil 41 which hold | maintains the metal oxide 10 on the outer side with the heater 1 for heating may be surrounded, and the double coil 41 By arranging the mesh-like member 21 so as to be in contact with the metal oxide 10 on the inner side, the vibration suppressing effect of the double coil 41 works and the metal oxide 10 can be prevented from falling. In addition, a large amount of the metal oxide 10 is held between the pitches of the double coils 41, and there is an effect of supplementing the lost metal oxide content accompanying the deterioration with time during discharge.
Moreover, since the double coil 41 has a mandrel, it is possible to suppress the deformation of the double coil 41 during processing and use.

(Third embodiment)
FIG. 6 is a schematic cross-sectional view of an indirectly heated cathode for a gas discharge tube according to the third embodiment. The third embodiment is different from the first and second embodiments in that the coil member is a single coil and the electric conductor is a linear member.

  As shown in FIG. 6, the indirectly heated cathode C3 for a gas discharge tube includes a heater 1, a single coil 45 as a coil member, a linear member 23 as an electric conductor, and a metal oxide as an electron emission material. 10.

  The single coil 45 is a coil member composed of a coil wound in a single coil shape, and a tungsten strand having a diameter of 0.15 mm is wound with a diameter of 1.7 mm and a pitch of 0.18 mm. The heater 1 is provided inside the single coil 45.

  Like the mesh member 21, the linear member 23 formed in a linear shape and having a predetermined length is a rigid body (metal conductor) having conductivity and belongs to the groups IIIa to VIIa, VIII, and Ib of the periodic table. Specifically, refractory metals such as tungsten, tantalum, molybdenum, rhenium, niobium, osmium, iridium, iron, nickel, cobalt, titanium, zirconium, manganese, chromium, vanadium, rhodium, rare earth metals (melting point 1000 ° C. or higher) Made of a single metal or an alloy thereof. In this embodiment, a linear member made of tungsten is used. The diameter of the linear member 21 is set to about 0.1 mm.

  The linear member 23 is provided on the inner side of the single coil 45 (between the heater 1 and the single coil 45) over the longitudinal direction of the single coil 45 and substantially orthogonal to the discharge direction. The linear member 23 is in a state of being electrically connected to the single coil 45. The linear member 23 is in contact with a plurality of coil portions inside the single coil 45, and forms a plurality of contacts with the single coil 45. The linear member 23 is grounded (GND) by being connected to the lead rod together with the ground-side terminal of the heater 1. When the plate-like member 3 is grounded, the single coil 45 is also grounded.

  The metal oxide 10 is held by the single coil 45 and the heater 1 for heating. The surface portion of the single coil 45 and the metal oxide 10 are exposed to the outside of the indirectly heated cathode C5 for gas discharge tube so that the surface of the metal oxide 10 and the surface portion of the single coil 45 become discharge surfaces, The surface portion of the single coil 45 is in contact with the surface portion of the metal oxide 10. The metal oxide 10 is provided in the same manner as in the first embodiment.

  As shown in FIG. 5, the heater 1 is in contact with the metal oxide 10 and the single coil 45 through the electric insulating layer 4. For this reason, the heat of the heater 1 can be reliably and efficiently transmitted to the metal oxide 10 and the single coil 45 during preheating. Further, as in the first embodiment, the loss of heat necessary for the hot cathode operation can be suppressed, the heat supply to the electrode from the outside, forced overheating is not required, and the electrode can be formed only by the heat by self-heating. Can be designed to work.

  From the above, in the indirectly heated cathode C3 for gas discharge tube of the present embodiment, the linear member 23 is provided in contact with the metal oxide 10 and in contact with the single coil 45. Therefore, the linear member 23 is provided. Effectively forms an equipotential surface on the back surface (the surface opposite to the discharge surface) of the single coil 45 together with the inner portion of the single coil 45. That is, the linear member 23 and the inner portion of the single coil 45 are configured by a plurality of electrical wirings (conducting paths) and are not restricted so that current flows in a single direction. Accordingly, the electrical resistance between the ends of the surface of the linear member 23 is remarkably small, the surface of the linear member 23 is almost equipotential, and the potential of the discharge surface composed of a plurality of discharge points or discharge lines is almost equal. Will be equal. In other words, the linear member 23 forms a plurality of electric circuits through which a discharge current can flow in a direction parallel to the discharge surface, that is, a plurality of paths (equipotential circuits) for discharge electrons (emissions). Become.

  Therefore, in the indirectly heated cathode C3 for a gas discharge tube, an equipotential surface is effectively formed on the back surface (the surface opposite to the discharge surface) of the single coil 45 by the linear member 23 and the inner portion of the single coil 45. Therefore, thermionic emission occurs in a wide area of the formed equipotential surface, the discharge area increases, the amount of electron emission per unit area (electron emission density) increases, and the load at the discharge position is reduced. Accordingly, it is possible to suppress the deterioration (mineralization), that is, the reduction of the thermoelectron emission ability, which is a deterioration factor by sputtering of the metal oxide 10 and oxidation with the reduced metal. As a result, the occurrence of local discharge can be suppressed and the life of the cathode can be extended. Further, since the movement of the discharge position is also suppressed, a stable discharge can be obtained for a long time. Moreover, since the discharge area increases, the operating voltage and the amount of generated heat of the indirectly heated cathode C3 for gas discharge tubes can be reduced.

  Further, in the indirectly heated cathode C3 for gas discharge tubes, the current density is slightly increased to slightly increase the load in relation to the increase in the discharge area. Damage can be reduced compared to. As a result, an indirectly heated cathode for a gas discharge tube with a large discharge current having almost the same shape as the conventional one can be provided, and a pulse operation and a large current operation can be realized.

  Moreover, since the linear member 23 is used as the electric conductor, an electric conductor having a configuration capable of suppressing the decrease in thermionic emission ability and the movement of the discharge position can be realized at a lower cost and more easily. Moreover, since the linear member 23 (electrical conductor) is a rigid body, it can be easily processed and can be provided in close contact with the metal oxide 10. Furthermore, many places where the linear member 23 and the metal oxide 10 contact can be provided easily.

  Further, in the indirectly heated cathode C3 for the gas discharge tube according to the present embodiment, the heater 1 is used as a core, and the single coil 45 that holds the metal oxide 10 is disposed around the heater 1 so that the inside of the single coil 45 is surrounded. By arranging the linear member 23 so as to be in contact with the metal oxide 10, the vibration suppressing effect of the single coil 45 works, and the metal oxide 10 can be prevented from falling.

(Fourth embodiment)
FIG. 7 is a schematic sectional view of an indirectly heated cathode for a gas discharge tube according to the fourth embodiment. The fourth embodiment is different from the first to third embodiments in having a base metal.

  As shown in FIG. 7, the indirectly heated cathode C4 for a gas discharge tube has a heater 1, a double coil 41, a metal oxide 10 as an electron-emitting material, and a base metal 31. Yes.

  The base metal 31 is formed in a cylindrical shape and has conductivity. The base metal 31 is made of, for example, molybdenum. The heater 1 is inserted and disposed inside the base metal 31. The double coil 41 is wound and fixed around the outer surface of the base metal 31 a plurality of times. In addition, the base metal 31 has a function of isolating the metal oxide 10 as the electron-emitting material from the electrical insulating layer 4 formed on the heater 1. The base metal 31 may be a medium or high melting point metal having a melting point higher than the operating cathode temperature. The base metal 31 is generally a cylindrical tubular member, but an arc-shaped (open shape) tubular member having a notch may be used.

  The base metal 31 is provided inside the double coil 41 (between the heater 1 for heating and the double coil 41) over the longitudinal direction of the double coil 41 and substantially orthogonal to the discharge direction. The base metal 31 is in an electrically connected state with the double coil 41. The base metal 31 is in contact with the plurality of coil portions inside the double coil 41, and forms a plurality of contacts with the double coil 41. The base metal 31 is grounded (GND) by being connected to the lead rod together with the ground-side terminal of the heater 1 for heating. When the base metal 31 is grounded, the double coil 41 is also grounded.

  The metal oxide 10 is held by the double coil 41. The surface portion of the double coil 41 and the metal oxide 10 are exposed to the outside of the indirectly heated cathode C4 for gas discharge tube so that the surface of the metal oxide 10 and the surface portion of the double coil 41 become discharge surfaces. The surface portion of the double coil 41 comes into contact with the surface portion of the metal oxide 10.

  From the above, in the indirectly heated cathode for gas discharge tube C4 of the present embodiment, the base metal 31 is provided in contact with the metal oxide 10 and in contact with the double coil 41. The equipotential surface is effectively formed together with the inner portion of the double coil 41 on the back surface (surface opposite to the discharge surface) of the double coil 41. That is, the base metal 31 and the double coil 41 are configured by a plurality of electrical wirings (conducting paths) and are not restricted so that current flows in a single direction. Therefore, the electric resistance between the ends of the surface of the base metal 31 is extremely small, and the surface of the base metal 31 is almost equipotential, and the potentials of the discharge surfaces composed of a plurality of discharge points or discharge lines are almost equal. . In other words, the base metal 31 forms a plurality of electric circuits through which a discharge current can flow in a direction parallel to the discharge surface, that is, a plurality of discharge electron (emission) paths (equipotential circuits). .

  Therefore, in the indirectly heated cathode C4 for a gas discharge tube, an equipotential surface is effectively formed on the back surface (the surface opposite to the discharge surface) of the double coil 41 by the base metal 31 and the double coil 41. Therefore, thermionic emission occurs in a wide area of the formed equipotential surface, the discharge area increases, the amount of electron emission per unit area (electron emission density) increases, and the load at the discharge position is reduced. Therefore, it is possible to suppress the deterioration (mineralization), that is, the reduction of the thermal electron emission ability, which is a deterioration factor by sputtering of the metal oxide 10 and oxidation with the reduced metal. As a result, the occurrence of local discharge can be suppressed and the life of the cathode can be extended. Further, since the movement of the discharge position is also suppressed, a stable discharge can be obtained for a long time. Further, since the discharge area increases, the operating voltage and the amount of generated heat of the indirectly heated cathode C4 for gas discharge tube can be reduced.

  Further, in the indirectly heated cathode C4 for gas discharge tubes, the current density is slightly increased and the load is slightly increased in relation to the increase in the discharge area. Damage can be reduced compared to. As a result, an indirectly heated cathode for a gas discharge tube with a large discharge current having almost the same shape as the conventional one can be provided, and a pulse operation and a large current operation can be realized.

  Moreover, since the double coil 41 has a mandrel, it is possible to suppress the deformation of the double coil 41 during processing and use.

  Next, based on FIGS. 8-10, the gas discharge tube using the indirectly heated cathode C1 for gas discharge tubes of the structure mentioned above is demonstrated. 8 is an overall perspective view of a gas discharge tube using the indirectly heated cathode C1 for the gas discharge tube, FIG. 9 is an exploded perspective view of the light emitting portion, and FIG. 10 is a cross-sectional view of the light emitting portion. In this embodiment, the indirectly heated cathode for a gas discharge tube is applied to a C1 side-on type deuterium gas discharge tube. As the indirectly heated cathode for the gas discharge tube, any of the indirectly heated cathodes C2 to C4 for the gas discharge tube may be used instead of the indirectly heated cathode C1 for the gas discharge tube.

  The deuterium gas discharge tube DT1 has a glass peripheral 61. As shown in FIG. 8, a light emitting unit assembly 62 is accommodated inside the outer peripheral unit 61, and the bottom of the outer peripheral unit 61 is hermetically sealed by a glass stem 63. Four lead pins 64 a to 64 d extend from the lower part of the light emitting unit assembly 62 and pass through the stem 63 and are exposed to the outside. The light emitting unit assembly 62 includes a shielding box structure in which an alumina discharge shielding plate (discharge shielding portion) 71 and a support plate 72 are bonded together, and a metal front cover 73 attached to the front surface of the discharge shielding plate 71. have.

  As shown in FIG. 9, a through hole is formed in the longitudinal direction in the rear portion of the support plate 72 having a convex cross-sectional shape, and a lead pin 64 a is inserted and held by the stem 63. A concave groove extending vertically downward is formed on the front surface of the support plate 72, and a lead pin 64 b extending from the stem 63 is immersed therein, and the support plate 72 is fixed to the stem 63 by these. A rectangular flat plate anode 74 is fixed to the lead pin 64b toward the front, and is held by coming into contact with two convex portions formed on the front surface of the support plate 72.

  As shown in FIG. 9, the discharge shielding plate 71 has a thin and wide convex cross-sectional structure as compared with the support plate 72, and a through hole 71 a is formed at a position corresponding to the central anode 74. . A through hole is formed in the vertical direction on the side of the convex portion of the discharge shielding plate 71, and an electrode rod 81 bent into an L shape is inserted therethrough. Then, with the discharge shielding plate 71 bonded to the support plate 72, the lower end of the electrode rod 81 and the tip of the lead pin 64c bent into an L shape are welded. The upper electrode rod 82 of the indirectly heated cathode C1 for gas discharge tubes is welded to the tip portion extending to the side of the electrode rod 81, and the lower electrode rod 83 is formed by bonding the discharge shielding plate 71 and the support plate 72 together. In the state, it is welded to the tip of the lead pin 64d bent in an L shape.

  As shown in FIG. 9, the metal focusing electrode 76 is an L-shaped metal plate that has a converging opening 76 a formed coaxially with the through hole 71 a of the discharge shielding plate 71 in the middle portion, and rearward at the upper part. A rectangular vertically long opening 76b is formed at the side portion in the direction of the indirectly heated cathode C1 for the gas discharge tube, and is bent at the front, and faces the indirectly heated cathode C1 for the gas discharge tube. The discharge shielding plate 71, the support plate 72, and the converging electrode 76 are each formed with four through holes at corresponding positions. Therefore, in a state where the discharge shielding plate 71, the support plate 72, and the converging electrode 76 are bonded together, they can be fixed to the stem 63 by inserting the two metal pins 84 and 85 bent in a U shape.

  As shown in FIGS. 8 and 9, the metal front cover 73 has a U-shaped cross section bent in four steps, and an opening window 73a for light projection is formed at the center. Two convex portions 73 b are formed at both ends, and these correspond to the four through openings 71 b formed at the front end portion of the discharge shielding plate 71. Therefore, the front cover 73 is fixed to the discharge shielding plate 71 by inserting the convex portion 73b into the through-opening 71b. In this state, the front end of the converging electrode 76 is in contact with the inner surface of the front cover 73 and is used for the gas discharge tube. The space where the indirectly heated cathode C1 is disposed and the light emitting space are separated.

  According to FIGS. 9 and 10, the converging electrode 76 has a converging opening 76a coaxially with the through hole 71a of the discharge shielding plate 71 at the center, but here, an opening restriction for restricting the opening diameter is provided. The plate 78 is fixed by welding. The aperture limiting plate 78 is bent in the direction of the anode 74 around the converging aperture 76a, so that the distance between the anode 74 and the aperture limiting plate 78 is smaller than the thickness of the discharge shielding plate 71.

  The arrangement of the electrodes in the light emitting section 62 assembled in this way is as shown in FIG. The anode 74 is sandwiched and fixed between the discharge shielding plate 71 and the support plate 72, and the opening limiting plate 78 welded to the converging electrode 76 is disposed so as to face the anode 74 through the through hole 71a of the discharge shielding plate 71. It is fixed to the discharge shielding plate 71. The indirectly heated cathode C1 for the gas discharge tube is in a space surrounded by the surface having the rectangular opening 76b of the discharge shielding plate 71, the front cover 73 and the converging electrode 76, and faces the opening limiting plate 78 through the rectangular opening 76b. Placed in.

  Next, the operation of the deuterium gas discharge tube DT1 will be described with reference to FIG. After the gas discharge tube indirectly heated cathode C1 is sufficiently heated, a trigger voltage is applied between the anode 74 and the gas discharge tube indirectly heated cathode C1 to start discharge. The flow path of the thermoelectrons at this time is only one path 91 (illustrated by a portion sandwiched between broken lines) due to convergence by the aperture limiting plate 78 of the focusing electrode 76 and shielding effect by the discharge shielding plate 71 and the support plate 72. Limited to one. That is, the thermoelectrons (not shown) emitted from the indirectly heated cathode C1 for the gas discharge tube pass through the opening limiting plate 78 from the rectangular opening 76b of the focusing electrode 76, pass through the through hole 71a of the discharge shielding plate 71, and the anode 74. It leads to. An arc ball 92 by arc discharge is generated in a space in front of the aperture limiting plate 78 and on the opposite side of the anode 74. The light extracted from the arc ball 92 is emitted in the direction of the arrow 93 through the opening window 73 a of the front cover 73.

  Thus, in the deuterium gas discharge tube DT1 of the present embodiment, a deuterium gas discharge tube having a long life and stable operation can be realized by using the indirectly heated cathode C1 for gas discharge tubes.

  The indirectly heated cathodes C1 to C4 for the gas discharge tube are gas discharge tubes other than the deuterium gas discharge tube DT1, for example, a head-on type deuterium gas discharge tube that extracts light from the top of the tube, a rare gas fluorescent lamp, or It can also be used as an electrode (an indirectly heated cathode for a gas discharge tube) such as a mercury fluorescent lamp. Specifically, the gas discharge tube using the indirectly heated electrode for gas discharge tube of the present invention has a discharge electrode that forms a pair including the indirectly heated electrode for gas discharge tube of the present invention, and the phosphor film is formed on the inner surface. A rare gas fluorescent lamp having a sealed container formed and having a rare gas sealed in the sealed container. The gas discharge tube using the indirectly heated electrode for gas discharge tube of the present invention has a pair of discharge electrodes including the indirectly heated electrode for gas discharge tube of the present invention, has a sealed container, On the other hand, there is a mercury lamp in which rare gas and mercury are enclosed. The gas discharge tube using the indirectly heated electrode for gas discharge tube of the present invention has a pair of discharge electrodes including the indirectly heated electrode for gas discharge tube of the present invention, and a phosphor film is formed on the inner surface. There is a fluorescent lamp which has a sealed container and in which a rare gas and mercury are sealed in the sealed container.

Further, the indirectly heated electrode for gas discharge tube of the present invention has an electrode 42 outside the container 41 and the indirectly heated gas discharge tube inside the container 41 as shown in FIG. It can be used for a one-sided external electrode type lamp that has type cathodes C1 to C4, encloses a rare gas inside the container 41, and is driven using a high-frequency power source 43. As described above, the indirectly heated electrode for gas discharge tube of the present invention can be used for the above-described low-pressure gas lamp and the like.
As the lighting circuit of the gas discharge tube DT2 such as the rare gas fluorescent lamp, the mercury lamp, or the fluorescent lamp described above, as shown in FIG. 12, a known tube having a glow tube 53, a ballast 54, and an AC power supply 55 is known. A starter (preheating start) type lighting circuit can be used. As the lighting circuit, a rapid start type can be used instead of the starter type. As a drive system, it is possible to correspond to a high-frequency lighting exclusive type (Hf).

  In the gas discharge tube using the indirectly heated electrode for gas discharge tube of the present invention, in the case of alternating current operation, a pair of electrodes (side heated cathodes C1 to C4 for gas discharge tube) emit electrons as a main function. It alternately serves as a cathode and an anode through which electrons flow. When functioning as an anode, a large amount of heat is generated in the electrode due to a voltage drop when electrons flow. By using the amount of heat generated when the electrode functions as an anode as the amount of heat necessary for thermionic emission when the electrode functions as a cathode, no heat is supplied from the heater 1 during continuous discharge of the gas discharge tube. Alternatively, stable sustained discharge can be realized with less heat supply than in direct current operation.

  Next, a lighting device suitable for the deuterium gas discharge tube DT1 using the indirectly heated cathode C1 for gas discharge tube will be described with reference to FIG. FIG. 13 is a circuit diagram showing a lighting device for the deuterium gas discharge tube DT1 using the indirectly heated cathode C1 for the gas discharge tube.

The lighting device 101 is connected between a constant current power source 103 as a power source connected between the indirectly heated cathode C1 for the gas discharge tube of the deuterium gas discharge tube DT1 and the anode 74, and between the anode 74 and the focusing electrode 76. The auxiliary lighting circuit unit 111 for generating a trigger discharge between the indirectly heated cathode C1 for gas discharge tube and the focusing electrode 76, and the indirectly heated cathode C1 for gas discharge tube and the anode 74 are connected, The heating heater 1 is energized for a predetermined period, and after the predetermined period has elapsed, the energization cutoff switching circuit 121 for cutting off the energization to the heater 1 is connected in series between the anode 74 and the constant current power source 103. It has the fixed resistor 131 for the electric current detection installed in connection.
The constant current power supply 103 supplies a DC open circuit voltage of about 160 V and a steady current of about 300 mA. The constant current power source 103 is connected in series with a negative resistance 105 for stabilizing discharge and a diode 107. The negative resistance 105 is set to about 50 to 150Ω.

  The auxiliary lighting circuit unit 111 includes a fixed resistor 113 installed in series between the anode 74 and the converging electrode 76, and a capacitor 115 connected in parallel to the fixed resistor 113. The energization cut-off switching circuit unit 121 includes a glow tube 123. A switch that is opened after the operation (lighting) of the deuterium gas discharge tube DT1 may be provided between the auxiliary lighting circuit unit 111 and the focusing electrode 76. In addition, instead of the glow starter type using the glow tube 123, an electronic start type using a semiconductor element having a timer function, or a mechanical (contact point) switch may be used regardless of the presence or absence of the timer function.

  Next, operation | movement of the lighting device 101 is demonstrated based on Fig.14 (a)-(f) and Fig.15 (a)-(e).

  Although not shown in FIG. 13, when the main power switch of the lighting device 101 of the deuterium gas discharge tube DT <b> 1 is turned on (started), power is supplied from the constant current power source 103 to the glow tube 123. When glow discharge occurs and the electrodes of the glow tube 123 come into contact with each other, power is supplied to the heater 1 of the indirectly heated cathode C1 for gas discharge tube, and the indirectly heated cathode C1 for gas discharge tube is preheated. (Period A1 in FIGS. 14A to 14F and FIGS. 15A to 15E). At this time, a voltage of about 130 V is applied from the constant current power source 103 between the indirectly heated cathode C1 for the gas discharge tube and the anode 74, and an electric field is generated from the anode 74 toward the indirectly heated cathode C1 for the gas discharge tube. Yes.

  When the trigger discharge is ready in this way, the glow discharge stops in the glow tube 123 and the electrodes of the glow tube 123 are separated, so that the capacitor 115 and the fixed resistor 113 connected in parallel from the constant current power source 103 are used. A potential of about 130 V is generated at the focusing electrode 76, and a trigger discharge is generated between the indirectly heated cathode C1 for gas discharge tube and the focusing electrode 76 (FIGS. 14A to 14F and 15A to 15A). Period A2) in e).

  Then, by generating the trigger discharge in this way, an arc discharge is generated between the indirectly heated cathode C1 for the gas discharge tube and the anode 74, and the indirectly heated cathode C1 for the gas discharge tube and the anode 74 are supplied from the constant current power source 103. Arc discharge stably continues until the main power switch is turned off on the basis of the current of about 300 mA supplied between (a period in FIGS. 14 (a) to (f) and FIGS. 15 (a) to (e)). A3). During the operation (lighting) of the deuterium gas discharge tube DT1, the voltage applied from the constant current power source 103 to the deuterium gas discharge tube DT1 by the fixed resistor 131 is about 160V to about 120V at the start. Will be reduced.

By the way, in the deuterium gas discharge tube DT1 using the indirectly heated cathode C1 for gas discharge tube, it can be driven by the relationship of the following formulas (3) and (4).
I _f0 = Ip (3)
V _f1 = 0 (4)
Where I _f0 : initial supply current to the heater for starting
Ip: discharge current
V _f1 : _Applied voltage to heating heater in operation With this lighting device 101, a lighting device for lighting the deuterium gas discharge tube DT 1 using the indirectly heated cathode C 1 for gas discharge tube can be realized. Further, one constant current power source 103 can provide power for preheating the indirectly heated cathode C1 for gas discharge tube, starting trigger discharge (discharge due to initial gas ionization), and main discharge, particularly for gas discharge tubes. A power source for preheating (heating heater) of the indirectly heated cathode C1 becomes unnecessary, and the number of parts can be greatly reduced and the configuration can be simplified.

  Further, in the lighting device 101, since the energization cut-off switching circuit unit 121 includes the glow tube 123, the energization cut-off switching circuit unit 121 can be realized simply and at low cost. Furthermore, since the auxiliary lighting circuit unit 111 includes the fixed resistor 113 and the capacitor 115, the auxiliary lighting circuit unit 111 can be realized simply and at low cost.

  In addition, since the lighting device 101 has the fixed resistor 131 for current detection, the voltage during operation of the deuterium gas discharge tube DT1 can be lowered, and the power consumption of the deuterium gas discharge tube DT1 is reduced. can do.

  In the present embodiment, a refractory metal is used as the electric conductor, but a thin porous metal, carbon fiber, or the like may be used instead of the refractory metal. Further, in order to improve the sputtering resistance and discharge performance of the metal oxide 10, a nitride or carbide such as tantalum, titanium, niobium or the like is applied to the surface of the metal oxide 10, or the double coils 2, 41, the single coil 45, Or you may make it adhere to the plate-shaped member 3, the mesh-shaped member 21, and the linear member 23. FIG.

  In the present embodiment, the surface portions of the double coils 2 and 41 and the single coil 45 are exposed. However, it is not always necessary to expose the surface portions of the double coils 2 and 41 and the metal oxide 10 is covered with the double coils 2 and 41. As long as the surface portions of the single coil 45 are in contact with each other, the surface portions of the double coils 2 and 41 and the single coil 45 may be covered with the metal oxide 10. In addition, by exposing the surface portions of the double coils 2 and 41 and the single coil 45, the discharge performance can be further improved.

It is a schematic front view which shows the indirectly heated cathode for gas discharge tubes which concerns on 1st Embodiment. It is a schematic side view which shows the indirectly heated cathode for gas discharge tubes which concerns on 1st Embodiment. (A) And (b) is a schematic top view which shows the indirectly heated cathode for gas discharge tubes which concerns on 1st Embodiment. It is a schematic sectional drawing which shows the indirectly heated cathode for gas discharge tubes which concerns on 1st Embodiment. It is a schematic sectional drawing which shows the indirectly heated cathode for gas discharge tubes which concerns on 2nd Embodiment. It is a schematic sectional drawing which shows the indirectly heated cathode for gas discharge tubes which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows the indirectly heated cathode for gas discharge tubes which concerns on 4th Embodiment. It is a whole perspective view which shows the gas discharge tube using the indirectly heated cathode for gas discharge tubes which concerns on 1st Embodiment. It is a perspective view in the state where the light emission part of the gas discharge tube using the indirectly heated cathode for gas discharge tubes concerning a 1st embodiment was decomposed. It is a cross-sectional view of the light emission part of the gas discharge tube using the indirectly heated cathode for gas discharge tubes which concerns on 1st Embodiment. It is a block diagram which shows the one-side external electrode type lamp | ramp using the indirectly heated cathode for gas discharge tubes which concerns on 1st Embodiment. It is a circuit diagram which shows the lighting circuit of the gas discharge tube using the indirectly heated cathode for gas discharge tubes which concerns on 1st Embodiment. It is a circuit diagram which shows the lighting device of the gas discharge tube using the indirectly heated cathode for gas discharge tubes which concerns on 1st Embodiment. (A)-(f) is a time chart which shows the operating voltage characteristic in the lighting device of the gas discharge tube using the indirectly heated cathode for gas discharge tubes which concerns on 1st Embodiment. (A)-(e) is a time chart which shows the operating current characteristic in the lighting device of the gas discharge tube using the indirectly heated cathode for gas discharge tubes which concerns on 1st Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Heater for heating, 2 ... Double coil, 3 ... Plate-like member, 4 ... Electrical insulation layer, 10 ... Metal oxide, 101 ... Lighting device, C1-C4 ... Indirectly heated cathode for gas discharge tubes, DT1 ... Heavy Hydrogen gas discharge tube, DT2 ... gas discharge tube.

Claims (8)

A gas discharge tube comprising a sealed container and a pair of indirectly heated electrodes provided inside the sealed container,
The pair of indirectly heated electrodes are:
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;
An electrical conductor provided in contact with the coil member on the inner side of the coil member and having a predetermined length,
The coil member, Ri Oh in multiple coil configured by winding a coil having a mandrel in a coil shape,
The electrical conductor is a refractory metal formed in a mesh shape or a plate shape, and is provided in contact with the metal oxide and in contact with a plurality of coil portions of the coil member. Gas discharge tube.   2. The gas according to claim 1, wherein the metal oxide contains an oxide of any one of barium, strontium, and calcium, a mixture of these oxides, or an oxide of a rare earth metal. Discharge tube.   The gas discharge tube according to claim 1, wherein the metal oxide is in contact with the heater for heating through the electrical insulating layer.   The gas discharge tube according to claim 1, wherein the coil member is in contact with the heater for heating through the electrical insulating layer. A gas discharge tube comprising a sealed container and a pair of indirectly heated electrodes provided inside the sealed container,
The pair of indirectly heated electrodes are:
A coil member having a mandrel and 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 refractory metal disposed between the coil member and the heater for heating in the longitudinal direction of the coil member, and formed in a mesh shape or a plate shape;
A metal oxide as an easy-electron emitting material provided in contact with the coil member;
And the refractory metal is in electrical contact with the coil member at a plurality of locations,
The gas discharge tube according to claim 1, wherein the coil member is a multiple coil formed by winding a coil in a coil shape. The gas discharge tube according to any one of claims 1 to 5 , wherein a rare gas or a rare gas and mercury are sealed in the sealed container. The gas discharge tube according to claim 6 , wherein a phosphor film is formed on an inner surface of the sealed container. The gas discharge tube according to any one of claims 1 to 7 , wherein the gas discharge tube is AC driven.

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