JP3944305B2 - Tube occlusion structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a closing portion structure for closing a closing tube of a bulb such as a mercury lamp, a metal halide lamp, or a halogen lamp.
[0002]
[Prior art]
In a tube, for example, a high pressure discharge lamp, a pair of electrodes are disposed opposite to each other in a spherical or elliptical light emitting tube made of quartz glass, and a light emitting metal such as mercury, a discharge gas, or the like is enclosed. A cylindrical occlusion tube is continuously provided at the end of the arc tube, and the electrode core rod having an electrode at the tip and the external lead rod are occluded in a state of being electrically connected by this occlusion tube. Since the thermal expansion coefficient of the electrode core rod and the quartz glass closing tube differ greatly, it cannot be closed by directly welding the closing tube to the electrode core rod. For this reason, it has been clogged by the foil sealing method and the step joining method, but recently, a functionally graded material molded with a non-conductive inorganic substance component such as silica and a conductive inorganic substance component such as molybdenum is sintered. It has been noticed that the closing tube at the end of the arc tube is closed with a closing portion structure formed into a substantially cylindrical shape by the method.
[0003]
The closed part structure formed of the functionally gradient material is rich in non-conductive inorganic substance components such as silica at one end, and the ratio of conductive inorganic substance components such as molybdenum toward the other end. It increases continuously or stepwise. Therefore, in the case of a functionally graded material formed of silica powder and molybdenum powder, the vicinity of one end of the closed structure is non-conductive and the thermal expansion coefficient is close to that of quartz glass, while the other The vicinity of the end portion is conductive and has a characteristic that the thermal expansion coefficient is close to that of molybdenum.
[0004]
The non-conductive region side end of the closed structure is inserted into a closed tube of a tube and heated and sealed with a gas burner. Therefore, the conductive region side end portion of the blocking portion structure protrudes from the blocking tube of the bulb or is in the extension portion of the blocking tube, but is exposed to the atmosphere anyway. Further, the rod-shaped external power supply member is fixed to the central hole of the closing portion structure and protrudes outward from the conductive region side end face.
[0005]
[Problems to be solved by the invention]
When a lamp with the closed tube of the bulb closed with a block structure made of functionally graded material is lit, the block structure also becomes hot, but the end of the closed region on the side of the conductive region is welded and sealed with the closed tube Since it protrudes from the stopper and is exposed to oxygen in the atmosphere, the conductive inorganic substance component of the functionally gradient material, such as molybdenum, may be oxidized. When molybdenum is oxidized, there is a problem that the electric resistance value increases to an abnormally high temperature and the lamp characteristics are remarkably deteriorated.
[0006]
For this reason, at least the outer surface of the portion projecting from the closing tube of the closing portion structure and the root portion of the external power supply member are covered with an anti-oxidation coating, for example, a thin film of SiO ₂ to prevent oxidation. However, since the periphery of the end surface on the conductive region side of the closed structure is an edge, it is difficult to apply the SiO ₂ coating liquid, and the periphery of the end surface on the conductive region side is exposed and exposed to oxygen in the atmosphere. . Therefore, the periphery of the end face on the conductive region side is easily oxidized, but when this portion is oxidized, the oxide falls into powder and falls. For this reason, when this lamp is combined with a mirror to form a light source device, oxide powder adheres to the reflecting surface of the mirror, impairing the reflection characteristics of the mirror.
[0007]
Further, the base portion of the rod-shaped external power supply member protruding from the end face of the closed portion structure body is covered with an anti-oxidation coating, for example, a thin film of SiO ₂ , but the external power supply member made of, for example, a molybdenum rod, Since the wettability with the SiO ₂ coating solution is poor, holes are formed in the SiO ₂ coating solution at the base of the external power supply member, and a path leading to the closed portion structure is formed. For this reason, there exists a malfunction in which the obstruction | occlusion part structure is oxidized from the root part of an external electric power feeding member.
[0008]
Therefore, the present invention provides a tube that does not oxidize the peripheral edge of the conductive region side end surface of the closed portion structure made of functionally gradient material or the conductive region side end surface of the closed portion structure around the root portion of the external power supply member. It is an object of the present invention to provide a closed structure.
[0009]
[Means for Solving the Problems]
In order to achieve such an object, the invention of claim 1 is characterized in that the conductive inorganic substance component and the nonconductive inorganic substance component have a continuous or stepwise concentration gradient in the longitudinal direction, and one side is a nonconductive region. In the closed part structure of a tube composed of a substantially cylindrical functionally graded material whose other side is a conductive region and closing the closed tube connected to the arc tube, the end surface of the closed region side of the closed part structure Chamfering the periphery of the outer power supply member and projecting at least the outer surface of the portion protruding from the welded sealing portion between the blocking portion structure and the blocking tube and the root portion of the external power feeding member protruding from the end surface of the blocking portion structure on the conductive region side . Cover with an antioxidant coating formed by application of the material .
[0010]
In the invention of claim 2, the conductive inorganic substance component and the non-conductive inorganic substance component have a continuous or stepwise concentration gradient in the longitudinal direction, one side being a non-conductive region and the other side being conductive. External power feeding projecting from the conductive region side end surface of a closed portion structure in a closed portion structure of a tube composed of a substantially cylindrical functionally gradient material as a region and closing a closed tube connected to an arc tube A gap is formed between the base part of the member and the closing part structure on the end surface side on the conductive region side, and at least the outer surface of the part protruding from the welded sealing part between the blocking part structure and the closing tube and the gap The base portion of the external power supply member is covered with an antioxidant coating.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows a discharge lamp in which a closing tube 12 of a bulb 10 is closed with a closing portion structure 50 made of a functionally gradient material. This discharge lamp is 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. However, the present invention is applicable to a discharge lamp such as a mercury lamp or a metal halide lamp, and further to a halogen lamp. Can be applied.
[0012]
In FIG. 1, an anode 20 and a cathode 30 made of tungsten are disposed opposite to each other inside an arc tube 11 at the center of a bulb 10 made of quartz glass. The tip of the cathode 30 is infiltrated with an electron emitting substance 31 such as barium. The arc tube 11 is filled with xenon gas and mercury as discharge gas. The blocking tubes 12, 12 are connected to both ends of the arc tube 11, and the ends of the blocking tubes 12, 12 are blocked by the blocking portion structure 50.
[0013]
The closing part structure 50 is a sintered body of functionally gradient material made of molybdenum, which is a conductive inorganic substance component, and silica, which is an insulating inorganic substance component, and the insulating region side end face 51 of the closing part structure 50 is It is made of almost 100% silica, and the molybdenum concentration increases gradually, and the composition of the conductive region side end face 52 is SiO ₂ 60 vol% + Mo 40 vol%. Then, the closing portion structure 50 is fitted into the closing tube 12 so that the insulating region side end surface 51 is in the direction of the arc tube 11, and the insulating region side end surface 51 side rich in silica is the closing tube 12 made of quartz glass. It is welded and sealed.
[0014]
The electrode core rod 40 of the anode 20 and the cathode 30 is made of a tungsten rod, is embedded in the axial non-conductive side central hole 53 formed in the closing portion structure 50, and is fixed by baking by sintering. Then, an external power supply member 60 made of a molybdenum rod is embedded in the conductive side central hole 54 of the closing portion structure 50, fixed by baking by sintering, and protrudes from the conductive region side end face 52 to the outside. At least the outer surface of the portion protruding from the closing tube 12 of the closing portion structure 50 and the root portion of the external power supply member 60 are covered with an antioxidant film 70, for example, a SiO ₂ coating, as indicated by a dotted line for convenience. Yes.
The central holes 53 and 54 are non-through holes, respectively. However, the central holes 53 and 54 are formed as one through hole, and the electrode core bar 40 is protruded from the end surface 52 on the conductive side, and the protruding portion is externally provided. The power supply member 60 may be used.
[0015]
Here, as shown in FIG. 2, the peripheral edge 52 a of the conductive region side end face 52 of the closing portion structure 50 is chamfered in an arc shape. The arc-shaped peripheral edge 52a uses a mold in which a circular arc-shaped part for a peripheral edge is formed when a pressure powder body for a closed structure is formed from a mixture of molybdenum powder and silica powder by a mold. However, the peripheral edge 52a of the conductive region side end face 52 of the closed portion structure 50 after sintering may be cut and chamfered. The chamfering of the peripheral edge 52a is not limited to the circular arc shape, and it is essential that the peripheral edge 52a has no sharp edge and can be easily applied with the SiO ₂ coating liquid.
[0016]
Further, the end portion of the conductive region side central hole 54 has a slightly larger diameter, and the root portion 61 of the external power feeding member 60 protruding from the conductive region side end surface 52 of the closing portion structure 50 and the conductive region side end surface. A gap 55 is formed between the closing portion structures 50 on the 52 side. The size and shape of the gap 55 are not limited to specific ones. In short, when the SiO ₂ coating liquid is applied, the gap 55 is filled with the SiO ₂ coating liquid, and the closing portion structure 50 Any hole may be used as long as it does not form a hole that causes a path leading to.
[0017]
When the antioxidant film 70 is a SiO ₂ coating, a SiO ₂ powder having a particle size of about 1 μm or a ceramic powder containing SiO ₂ is dispersed in a mixed solution of butyl oxide and 1% nitrocellulose to prepare a SiO ₂ coating solution. And applied to the outer surface of the molded product temporary sintered body of the closing portion structure 50 by brushing or dipping. At this time, since the peripheral edge 52a of the conductive region side end surface 52 is chamfered, the peripheral edge 52a of the conductive region side end surface 52 can also be reliably applied as shown in FIG.
[0018]
In addition, since the gap 55 is formed between the root portion 61 of the external power supply member 60 and the closed portion structure 50 on the conductive region side end face 52 side, the external power supply member 60 has wettability with the SiO ₂ coating liquid. Despite being bad, the gap 55 is filled with the SiO ₂ coating liquid. Therefore, a path through which the atmosphere communicates with the closed portion structure 50 is not formed in the root portion 61 of the external power supply member 60.
[0019]
Thereafter, the SiO ₂ coating as the antioxidant film 70 is formed on the outer surface of the closed portion structure 50 by heating at 1700 ° C. during the main sintering of the temporary sintered body to a thickness of about 50 μm. Since the peripheral edge 52a of the region side end face 52 and the root portion 61 of the external power supply member 60 are reliably covered with the antioxidant film 70, molybdenum contained in the closed portion structure 50 in these portions is not oxidized. .
[0020]
In the case of claim 2, the anti-oxidation film 70 is a film formed from a SiO ₂ coating solution. The gap 55 is formed between the root portion 61 of the external power supply member 60 and the closing portion structure 50 on the conductive region side end face 52 side. That is, the coating is not limited to a coating formed by applying a liquid material, and may be a metal coating with high oxidation resistance having a thickness of about 10 μm such as Pt, Re, Rh, or Cr. These metal films are formed by sputtering, vacuum deposition, plating, or the like. This metal film is also formed in the gap 55, and molybdenum contained in the closed portion structure 50 in these portions is not oxidized.
[0021]
【The invention's effect】
As described above, the present invention chamfers the periphery of the conductive region side end face of the closing portion structure made of functionally graded material, and also projects the external power feeding member protruding from the conductive region side end surface of the closing portion structure. Since a gap is formed between the base portion and the closed portion structure on the conductive region side end surface side, the periphery of the conductive region side end surface and the root portion of the external power feeding member can be reliably covered with the antioxidant coating, Conventionally, it is possible to provide a closed-bulb structure of a tube that is not easily oxidized.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a discharge lamp sealed with a closing portion structure made of a functionally gradient material.
FIG. 2 is an explanatory diagram of a blocking portion structure before forming an antioxidant coating.
FIG. 3 is an explanatory diagram of a blocking portion structure after an antioxidant coating is formed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Valve | bulb 11 Light emission tube 12 Blocking tube 20 Anode 30 Cathode 31 Electron emitting material 40 Electrode core rod 50 Blocking part structure 51 Non-conductive region side end surface 52 of the blocking unit structure Conductive region side end surface 52a of the blocking unit structure Edge 53 of the conductive region side non-conductive region side central hole 54 of the blocking portion structure Conductive region side central hole 55 of the blocking portion structure Clearance 60 External power supply member 61 Base portion 70 of the external power supply member Antioxidation coating

Claims (2)

Conductive inorganic material component and non-conductive inorganic material component have a continuous or stepwise concentration gradient in the longitudinal direction, a substantially cylindrical gradient function in which one side is a non-conductive region and the other side is a conductive region In the closed part structure of the tube that is made of a material and closes the closed tube connected to the arc tube,
The peripheral edge of the end surface on the conductive region side of the closing portion structure is chamfered, and at least from the outer surface of the portion protruding from the welded sealing portion between the closing portion structure and the closing tube and from the end surface of the closing portion structure on the conductive region side A closed tube structure according to claim 1 , wherein a base portion of the projecting external power supply member is covered with an antioxidant coating formed by applying a liquid material . Conductive inorganic material component and non-conductive inorganic material component have a continuous or stepwise concentration gradient in the longitudinal direction, a substantially cylindrical gradient function in which one side is a non-conductive region and the other side is a conductive region In the closed part structure of the tube that is made of a material and closes the closed tube connected to the arc tube,
A gap is formed between the root portion and the conductive region side of the end surface of the closure part structure of the external power supply member protruding from the conductive region-side end face of the closure portion structure, and at least occlusion structure closed tube A closed structure of a tube, wherein an outer surface of a portion protruding from the welded sealing portion, the inside of the gap, and a root portion of an external power feeding member are covered with an anti-oxidation coating.

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