JPH11297272A - Tubular bulb mount - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tubular bulb mount with long lamp life in which an alloy having a low melting point is not formed on the surface of an electrode or filament coil in the sintering of a blocking body consisting of a graded function material, and oxidation of the blocking body is suppressed. SOLUTION: An electrode core bar 40 and electrode 20 to be shrinkage-fitted to the hole 53 of a blocking body 50 are formed of different members, or the electrode core bar is divided into a first electrode core bar 41 holding the electrode and a second electrode core bar 42 shrinkage-fitted by baking to the hole of the blocking body 50. Otherwise, a lead wire and filament coil to be shrinkage-fitted are formed of different members, and bonded together after main sintering. The first electrode core bar and second electrode core bar or the lead wire and filament coil are connected to each other by a connecting member 60 having a large coefficient of thermal expansion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lamp mount in which an electrode core rod and a lead wire are fixed to a closing member for closing a closing tube of a discharge lamp or a halogen lamp.

[0002]

2. Description of the Related Art In a bulb, for example, a discharge lamp, a pair of electrodes are arranged opposite to each other in a spherical or elliptical spherical arc tube made of quartz glass, and a luminous metal such as mercury and a discharge gas are sealed therein. A tubular blocking tube is connected to the end of the arc tube, and the closing tube is closed by an electrode mount closing member in which an electrode rod having an electrode at the tip is fixed to a hole of the closing member. You. Here, since the electrode core rod made of tungsten and the plugged tube made of quartz glass have greatly different coefficients of thermal expansion, the plugged tube cannot be directly welded and closed to the electrode rod.

[0003] For this reason, in the past, the sealing was performed by a foil sealing method or a step joining method, but recently, a functionally gradient material formed of an insulating inorganic material component such as silica and a conductive inorganic material component such as molybdenum has been used. Attention has been paid to closing an obstruction tube connected to an end of an arc tube with an obstruction formed in a substantially cylindrical shape by a sintering method. The closed body formed of such a functionally graded material has one end rich in an insulating component such as silica, and the proportion of a conductive component such as molybdenum is continuously or gradually increased toward the other end. It will increase. Therefore, in the case of a functionally gradient material formed of silica powder and molybdenum powder, the vicinity of one end of the closing body is
It is insulative and has a coefficient of thermal expansion close to the coefficient of thermal expansion of quartz glass, and the vicinity of the other end has conductivity and a coefficient of thermal expansion close to that of molybdenum.

[0004] Such a functionally graded material can increase the gradient at which the ratio between the insulating inorganic material component and the conductive inorganic material component changes, so that the closure formed of the functionally graded material has an axial length. , The insulating component on one end face can be made rich (rich) and the conductive component on the other end face can be made rich. In addition, since the functionally graded material does not have a boundary surface where the composition of the constituents changes greatly, heat shock and mechanical strength are strong. Therefore, the sealing portion for welding the closing body to the closing tube can be brought close to the central portion of the arc tube, which becomes hot at the time of lighting, and the length of the closing tube in the axial direction is short. Have the advantages that can be.

[0005]

When a closed body is formed from a functionally gradient material comprising a conductive inorganic material component (for example, molybdenum) and an insulating inorganic material component (for example, silica),
First, a powder mixture is prepared by adding a binder to these powders in which the mixing ratios are sequentially changed, and the powder mixture is pressed in a mold to obtain a substantially cylindrical pressure-molded body. Then, the press-formed body is temporarily sintered at a temperature of about 1300 ° C. to obtain a temporarily sintered body. Next, a hole is formed in the axis of the pre-sintered body so as to bury an electrode core rod therein. Alternatively, it is pressed in a mold having a protruding member for forming a hole to form a press-formed body in which holes are formed in advance, and this is pre-sintered.
Then, an electrode core rod integrated with an electrode made of, for example, tungsten is inserted into the hole of the pre-sintered body, and then the main body is sintered at a temperature of about 1850 ° C.

By the way, when the functionally graded material is fully sintered at such a high temperature, silica, which is an insulating inorganic substance component of the functionally graded material, evaporates and adheres to the electrode at the tip of the electrode rod to form S.
i forms an alloy with tungsten. That is, the Si-W alloy is formed on the surface of the electrode made of tungsten. Since the melting point of this alloy is lower than that of tungsten, when such an electrode mount is mounted on a closed tube of an arc tube to form a discharge lamp, the temperature of the electrodes, especially the anode, is 200 when the lamp is turned on.
Since the temperature reaches 0 to 3000 ° C., the Si—W alloy is melted, and the electrode is deformed at an early stage. When the electrodes are deformed, the radiance of the arc discharge is significantly reduced, and the lamp has a short life. In addition, in a halogen lamp, when silica evaporated during the main sintering adheres to a filament coil made of tungsten, an Si-W alloy is similarly formed, and since this alloy has a higher vapor pressure than tungsten, it is formed on the inner wall of the arc tube during a lighting operation. There is a problem that the evaporated substance adheres and blackens.

[0007] The cathode may be impregnated with an electron-emitting substance such as barium at its tip.
If silica evaporated during main sintering adheres to the tip of the cathode,
Electron emission on the cathode tip surface deteriorates. In such a case, the tip surface of the cathode becomes abnormally hot, and the cathode material, tungsten and the electron-emitting substance, evaporate at an early stage, and the evaporated substance adheres to the inner wall of the arc tube and becomes black, thereby shortening the life of the lamp. There is a problem.

Further, as described above, the temperature of the electrode reaches 2000 to 3000 ° C. at the time of lighting, and this high-temperature heat is transmitted to the closing body made of the functionally graded material via the electrode core rod. Accordingly, heat is also transmitted to the molybdenum-rich portion of the closure made of the functionally graded material, but the molybdenum-rich portion of the closure is exposed to oxygen in the atmosphere, so that the molybdenum that has become hot is oxidized. When molybdenum is oxidized, the electric resistance increases, causing abnormal heat generation, and there is a problem that the lamp has a short life due to mechanical destruction. Further, in the halogen lamp, similarly to the discharge lamp, there is a problem in that abnormal heat is generated due to oxidation occurring in the molybdenum-rich portion of the closed body, resulting in mechanical damage.

Accordingly, a first object of the present invention is to provide a mount for a discharge lamp having a long lamp life without forming an alloy having a low melting point on a surface of an electrode or adhering silica to prevent electron emission. A second object of the present invention is to provide a halogen lamp mount having a long life without forming an alloy having a low vapor pressure on the surface of a filament coil. A second object of the present invention is to suppress the oxidation of an obstruction made of a functionally graded material. And provide a mount for a lamp having a long lamp life.

[0010]

In order to achieve the above object, a first aspect of the present invention relates to a discharge lamp, which comprises a functionally gradient material composed of a conductive inorganic material component and an insulating inorganic material component, and emits light. In a hole of a closed body that seals a closed tube connected to a tube, an electrode core rod having an electrode at its tip is sintered and sintered in a tube bulb mount, and the electrode core rod and the electrode are separated by a separate member. After the electrode core rod is tightened in the hole of the closing body, the electrode is joined to the tip of the electrode core rod.

Further, as in the second aspect of the present invention, the obstruction is made of a functionally gradient material composed of a conductive inorganic material component and an insulating inorganic material component, and seals a closed tube connected to the arc tube. In a tube mount in which an electrode core rod having an electrode at its tip is sintered and sintered in a hole of the body, the electrode core rod is sintered in a hole of the first electrode core rod holding the electrode and the closing body. Claims: The first electrode rod and the second electrode rod may be connected to each other so as to be electrically connected after the second electrode rod is divided into the second electrode rods to be clamped, and the second electrode rods are baked into holes of the closing body. The same object as the first invention can be achieved.

Furthermore, as in the invention of claim 3, in the invention of claim 2, the connecting portion between the first electrode core rod and the second electrode core rod made of tungsten is made of a metal having a larger coefficient of thermal expansion than tungsten. When the connection member is fixed to the first electrode core rod and the second electrode core rod by welding or caulking, the first member is turned on at the time of lighting.
Since the end surfaces of the electrode core rod and the second electrode core rod are slightly separated from each other and heat transfer is greatly impaired, it is possible to more completely prevent the closed body made of the functionally graded material from being oxidized.

A fourth aspect of the present invention relates to a halogen lamp, wherein the closing member is made of a functionally gradient material composed of a conductive inorganic material component and an insulating inorganic material component and seals a closing tube connected to the arc tube. In the tube mount, in which the filament coil and the lead wire connected to the filament coil are sintered and tightened in the hole, the lead wire and the filament coil are formed as separate members, and after the lead wire is tightened in the hole of the closing body, Then, a filament coil is connected to the end of the lead wire.

Furthermore, as in the fifth aspect of the present invention, in the fourth aspect of the invention, the connecting portion between the tungsten lead wire and the filament coil is covered with a metal connecting member having a larger coefficient of thermal expansion than tungsten. When the connecting member, the lead rod and the filament coil are fixed by welding or caulking, respectively, the end surfaces of the lead rod and the filament coil are slightly separated at the time of lighting, so that the heat transmission is greatly impeded. Oxidation of the body can be more completely prevented.

[0015]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows a xenon short arc lamp having a rated power of 250 W, a lamp voltage of 20 V and a lamp current of 12.5 A using a mount according to the first aspect of the present invention. And the like, and also a halogen lamp.

In FIG. 1, a quartz glass bulb 10 is provided.
Inside the central arc tube 11, an anode 20 and a cathode 30 made of tungsten are arranged to face each other. At the tip of the cathode 30, an electron emitting material 31 such as barium is sealed, and xenon gas and mercury as a discharge gas are sealed.
The closing tubes 12, 12 are connected to both ends of the arc tube 11, and the ends of the closing tubes 12, 12 are closed by closing members 50, which are components of the mount. As a specific example, the arc tube 11 has an outer diameter of 20 mmφ and a wall thickness of 2 m.
m, spherical shape with an internal volume of 3 cc. The anode 20 and the cathode 30 have a maximum diameter of 5 mmφ and a length of 15 mm,
Xenon gas filling pressure 8 atm, mercury amount 1.5μ
1, the closing body 50 is 4.3 mm in diameter and 15 m in length
m.

The closing body 50 is a sintered body of a functionally gradient material comprising a conductive inorganic substance component and an insulating inorganic substance component,
The insulating end face 51 is fitted into the closed tube 12 so that it faces the arc tube 11, and the end face 51 is welded to the quartz glass closed tube 12. The insulating end face 51 of the closing body 50 is made of, for example, almost 100% silica,
The end face 52 on the conductive side is SiO ₂ 60 vol% + Mo 40 v
ol% of the composition.

The electrode rods 40 of the anode 20 and the cathode 30, which are components of the mount, are made of a tungsten rod having an outer diameter of 2 mm. The electrode core rod 40 is embedded in an axial hole 53 formed in the closing body 50 and fixed by baking by sintering.
mm. The hole 53 is a non-through hole reaching a portion having electric conductivity. However, the hole 53 may be a through hole, and the electrode core rod 40 may protrude from the end face 52 on the conductive side. Then, the anode 20 and the cathode 30 and the electrode mandrel 40
Is a separate member, and the anode 20 and the cathode 30 are
0.

Next, a method of manufacturing such a mount will be described. The conductive inorganic substance component and the insulating inorganic substance component of the functionally gradient material are, for example, molybdenum powder having an average particle diameter of 1.0 μm and silica powder having an average particle diameter of 5.6 μm. First, a plurality of powder mixtures in which the mixing ratio of molybdenum powder and silica powder is changed is prepared. As the insulating inorganic substance component of the functionally gradient material, in addition to the above-mentioned silica powder, if the arc tube is made of ceramic, the ceramic powder may be used. As a component, of course, other than the molybdenum powder, an appropriate metal conductive material powder such as tungsten, niobium, and nickel can be used.

This powder mixture is mixed with an organic binder, for example a solution of about 23% of stearic acid. Then, the powder mixture is filled into a mold having a protruding member for a hole so that the mixing ratio of the molybdenum powder and the silica powder changes sequentially. Then, for example, 1.5 t / c from the outside of the cylindrical mold
A pressure is applied with a load of m ² to obtain a substantially cylindrical pressure-formed body in which holes are formed. Further, the obtained pressure-formed body is sintered in a hydrogen atmosphere at 1200 ° C. for 30 minutes to remove the organic binder to obtain a temporarily sintered body.

Next, an electrode core rod 40 to which the anode 20 and the cathode 30 are not fixed is inserted into the hole of the pre-sintered body, and a non-oxidizing atmosphere or a vacuum state of about 10 ⁻² Pa is applied.
The main sintering is performed by sintering at 1850 ° C. for 10 minutes. As a result, the hole 53 contracts and the electrode core bar 40 is shrunk. At this time, silica, which is an insulating inorganic substance component of the functionally graded material, evaporates. However, since the anode 20 and the cathode 30 are not fixed to the tip of the electrode core rod 40, they adhere to the surfaces of the anode 20 and the cathode 30. With no melting point and low melting point
No i-W alloy is formed.

Thereafter, the tips of the electrode core rods 40 tightened into the closing portions 50 are pressed into the holes of the anode 20 and the cathode 30 via a spacer made of a soft refractory metal, for example, Ta, for preventing detachment. And fixing by welding with a YAG laser, a mount is completed in which silica does not adhere to the surfaces of the anode 20 and the cathode 30 and a Si-W alloy having a low melting point is not formed.

When the xenon short arc lamp shown in FIG. 1 equipped with such a mount is turned on, the anode 20 and the cathode 30 are deformed because the low melting point Si—W alloy is not formed on the surfaces of the anode 20 and the cathode 30. Without
High radiance of arc discharge can be maintained for a long time. Further, since silica is not attached to the surfaces of the anode 20 and the cathode 30, the anode 20 and the cathode 30 do not become abnormally high in temperature, the evaporation of tungsten is small, and the blackening of the arc tube is suppressed. Incidentally, when the lamp life test was performed, the life was 1.5 times longer than that of the conventional product.

FIG. 2 shows a xenon short arc lamp using the mount according to the second aspect of the present invention. This lamp is the same as the xenon short arc lamp shown in FIG. 1 except that the electrode core 40 is burned into the first electrode core 41 integrated with the anode 20 or the cathode 30 and the hole 53 of the closing body 50. It is divided into second electrode core rods 42 to be tightened. That is, the second electrode core rod 42 is inserted into the hole of the temporary sintered body of the closing body 50.
Inserting and sintering at 1850 ° C. for 10 minutes to perform main sintering, and thereafter, the end faces of the second electrode core rod 42 and the first electrode core rod 41 are butted and fixed by welding with a YAG laser. As with the mount of the first invention, the anode 20 and the cathode 3
A mount is completed in which silica causing an abnormally high temperature does not adhere to the surface of No. 0 at the time of lighting and no Si-W alloy having a low melting point is formed. Therefore, a lamp using such a mount can be a lamp having a long lamp life, like the lamp using the mount of the first aspect of the present invention.

FIG. 3 shows a xenon short arc lamp using the mount according to the third aspect of the present invention.
0 and the first electrode core 41 and the hole 5 of the closing body 50
It is the same as the mount according to the second aspect of the present invention, which is divided into the second electrode core rods 42 to be tightened to 3. And
The second electrode core rod 42 is inserted into the hole of the pre-sintered body of the closing body 50, and the main electrode is sintered. Then, the high melting point metal is connected to the connecting portion between the second electrode core rod 42 and the first electrode core rod 41. A molybdenum plate having a larger coefficient of thermal expansion than tungsten is covered with a pipe-shaped connecting member 60, and the connecting member 60 and the second electrode
And the connecting member 60 and the first electrode core rod 41 are fixed by welding or swaging. That is, the second electrode core rod 42 and the first electrode core rod 41 are connected via the connecting member 60 without being directly fixed. A specific example of the connecting member 60 is a pipe having a plate thickness of 0.1 mm and a length of 6 mm, and the ends of the second electrode core rod 42 and the first electrode core rod 41 are inserted and fixed by 3 mm each. In addition, the connecting member 60 does not need to be a complete pipe, and if the mechanical strength is sufficient,
Molybdenum foil with a C-shaped cross section, a plurality of strips,
Further, it may be a coil.

Such a mount is the same as the mounts of the first and second aspects of the present invention.
Since the silica causing the abnormally high temperature does not adhere to the surface of the lamp when the lamp is turned on, and the Si-W alloy having a low melting point is not formed, the lamp can have a long lamp life. , The second electrode core rod 42 and the first
Since the connecting member 60 expands more than the electrode core 41, a gap is formed between the end surfaces of the second electrode core 42 and the first electrode core 41. Therefore, the anode 20 and the cathode 30
The transmission of the high-temperature heat from the first electrode core rod 41 to the second electrode core rod 42 is hindered. For this reason, the temperature rise of the closing body 50 made of the functionally graded material is suppressed, and oxidation of molybdenum, which is a conductive inorganic substance component of the functionally graded material exposed to the oxygen in the atmosphere, does not proceed, and the lamp having a long lamp life is not used. Can be a sphere.

Next, an embodiment in which the present invention is applied to a halogen lamp will be described. FIG. 4 shows one end of a double-ended sealed halogen lamp having a rated power consumption of 5 kW, and the other end has the same structure. The end of the quartz glass arc tube 11 is a closed tube 12, and the closed tube 12 is closed by a closed body 50 made of a functionally graded material. And the arc tube 11
A filament coil 70 made of tungsten is arranged along the axis of the coil. The lead wire 80 made of a tungsten wire having an outer diameter of 1.6 mm is connected to the filament coil 7.
A part different from 0 is embedded in an axial hole 53 formed in the closing body 50, fixed by baking by sintering, and protruding into the arc tube 11 from a non-conductive end face.
The hole 53 is a non-through hole reaching a portion having electric conductivity. However, the hole 53 may be formed as a through hole and protrude to the outside from an end surface on the conductive side.

The tip of the lead rod 80 is connected to the end of the filament coil 70 after fixing the lead wire 80 to the hole 53 by sintering. Therefore, the silica that evaporates when the closing body 50 is fully sintered at a high temperature does not adhere to the filament coil 70. That is, since a Si-W alloy having a higher vapor pressure than tungsten is not formed, it is possible to suppress the evaporation substance from adhering to the inner wall of the arc tube 11 and causing blackening during the lighting operation.

Here, the connecting member 60 described above is put on the connecting portion between the lead wire 80 and the filament coil 70, and the connecting member 60 and the lead wire 80, and the connecting member 60 and the filament coil 70 are fixed by welding or swaging. Is good. With such a structure, at the time of lighting, the connecting member 60 is smaller than the lead wire 80 and the filament coil 70.
Is larger, a gap is formed between the lead wire 80 and the end face of the filament coil 70. Therefore,
The transmission of the high-temperature heat of the filament coil 70 to the lead wire 80 is hindered. For this reason, the temperature rise of the closing body 50 made of the functionally gradient material is suppressed, and oxidation of molybdenum, which is a conductive inorganic substance component of the functionally gradient material exposed to oxygen in the atmosphere, does not proceed, and the lamp having a long lamp life is not used. Can be a sphere.

[0030]

As described above, according to the present invention,
Since silica does not adhere to the surface of the electrode or filament coil and no Si-W alloy is formed, blackening of the arc tube is suppressed, and in the case of a discharge lamp, the high radiance of arc discharge increases for a long time. A bulb that is maintained and has a long lamp life can be obtained. Further, the high-temperature heat of the electrodes and the filament coil is not easily transmitted to the closing body made of the functionally gradient material, and the oxidation of the conductive inorganic substance component of the functionally gradient material is suppressed, so that the lamp can have a long lamp life.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view of an embodiment of the invention according to claim 2;

FIG. 3 is a sectional view of an embodiment of the invention according to claim 3;

FIG. 4 is a sectional view of an embodiment of the invention of claim 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Bulb 11 Arc tube 12 Closure tube 20 Anode 30 Cathode 31 Electron emission material 40 Electrode core rod 41 1st electrode core rod 42 2nd electrode core rod 50 Closure body 51 Non-conductive side end face of closure body 52 Conductive side end face of closure body 53 Closure Hole 60 Connection Member 70 Filament Coil 80 Lead Wire

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Koji Tagawa, Inventor 1194, Sado Bessho-cho, Himeji-shi, Hyogo Ushio Electric Co., Ltd. Inside

Claims (5)

[Claims] 1. A hole made of a functionally graded material composed of a conductive inorganic material component and an insulating inorganic material component, wherein a hole in a closing body for sealing a closing tube connected to an arc tube is provided at an end thereof with an electrode. Wherein the electrode core rod and the electrode are separate members, and after the electrode core rod is tightened in the hole of the closing body, the electrode core rod is sintered. A tube mount characterized in that an electrode is joined to the tip of a core rod. 2. A hole made of a functionally gradient material composed of a conductive inorganic material component and an insulating inorganic material component. Wherein the electrode core rod is divided into a first electrode core rod holding an electrode and a second electrode core rod tightened in a hole of the closing body. And the second
A tube mount, wherein the first electrode core and the second electrode core are connected so that conduction can be obtained after the electrode core is fastened to the hole of the closing body. 3. A connecting portion between the first electrode core bar and the second electrode core bar made of tungsten is covered with a metal connecting member having a larger thermal expansion coefficient than tungsten, and the connecting member and the first electrode core are connected to each other. The tube mount according to claim 2, wherein the rod and the second electrode rod are fixed by welding or caulking, and the end faces of the first electrode rod and the second electrode rod are separated at the time of lighting. . 4. A filament coil made of a functionally graded material composed of a conductive inorganic material component and an insulating inorganic material component, the filament coil being provided in a hole of a closing body for sealing a closing tube connected to an arc tube. In a tube mount in which a lead wire connected to a filament coil is sintered and sintered, the lead wire and the filament coil are separate members,
A tube mount characterized in that a filament coil is connected to the tip of the lead wire after the lead wire is tightened in the hole of the closing body. 5. A connecting portion between a tungsten lead wire and a filament coil is covered with a metal connecting member having a larger coefficient of thermal expansion than tungsten, and the connecting member, the lead rod and the filament coil are welded or swaged, respectively. 5. The tube mount according to claim 4, wherein the end surface of the lead rod and the filament coil are separated when the lamp is lit.