JP3183884U - Molybdenum foil for high pressure discharge lamp, electrode mount for high pressure discharge lamp, high pressure discharge lamp, and coating member for processing molybdenum foil for high pressure discharge lamp - Google Patents

Abstract

The present invention provides a molybdenum foil capable of preventing breakage when an electrode is attached to a molybdenum foil by welding in the manufacture of an electrode mount for a high-pressure discharge lamp.
In a molybdenum foil 6 used for electrode mounting of a high-pressure discharge lamp, the molybdenum foil 6 has a longitudinal direction and a short-side direction, and a base 10 and a distal end are formed extending from the base 10 in the longitudinal direction. The distal end portion 12 has a distal end edge portion 16 and a distal end central portion 18 extending adjacent to each other in the longitudinal direction, and an outer edge portion 17b of the distal end edge portion 16 has a knife edge shape. However, the thickness of the tip center portion 18 is greater than the thickness of the tip edge portion 16 at the boundary portion 14 b between the tip edge portion 16 and the tip center portion 18.
[Selection] Figure 2

Description

  The present invention relates to a molybdenum foil for high pressure discharge lamps, an electrode mount for high pressure discharge lamps, a high pressure discharge lamp, and a coating member for processing molybdenum foil for high pressure discharge lamps.

  A high-pressure discharge lamp has a pair of electrodes facing each other in an arc tube, and an electrode mount having a lead wire for introducing current from the outside and a strip-shaped molybdenum foil for connecting the electrode and the lead wire is sealed in quartz glass It is composed by doing. The arc tube is sealed by sealing a molybdenum foil to quartz glass. The sealed portion of the arc tube needs to have sufficient adhesion strength to keep the discharge space airtight. The mercury vapor pressure during lighting has been around 100 atm in the past, but in recent years, ultra-high pressure discharge lamps with a mercury vapor pressure exceeding 200 atm have been manufactured, and an improvement in adhesion strength is required. Has been. For this reason, various technical developments have been made to strengthen the adhesion strength between quartz glass and molybdenum foil, and it has become known that the shape of the molybdenum foil strongly affects the sealing performance and pressure resistance of the arc tube. . Based on this background, various studies have been made so far regarding the shape and processing method of molybdenum foil.

  For example, Patent Document 1 discloses that the tip and side edges of a molybdenum foil sealed in a quartz glass arc tube have a knife edge shape. In this document, it is easy to perform good sealing between the molybdenum foil and the quartz glass adhering to the molybdenum foil by making the molybdenum foil into such a shape. It is disclosed that cracks are reduced. Further, it is described that the knife edge shape processing of the tip is performed by electropolishing in a sulfuric acid-based electrolytic polishing liquid in which molybdenum is previously melted at a rate of 5.0 mg / ml or more.

  Patent Document 2 discloses that the shape of the molybdenum foil in a plan view is formed by cutting off two corners on one side in the longitudinal direction of the rectangle (side to which the electrode is bonded) obliquely to form a substantially hexagonal shape. In order to process the edge of the molybdenum foil including the cut-off portion into a knife edge shape, it is disclosed to perform electrolytic polishing and chemical polishing after cutting off.

  Similarly, Patent Document 3 discloses chamfering by cutting out two corners on the side where the molybdenum foil electrode is bonded. It has been disclosed that since burrs are generated on the cut surface, it is desirable to remove the burrs by electrolytic etching.

  Patent Document 4 discloses processing the two corners on the side where the molybdenum foil electrode is joined into a curved shape. Furthermore, it is disclosed that the knife edge shape processing is performed by electropolishing with an aqueous solution of phosphoric acid or the like.

JP 2004-227970 A JP 2011-49136 A Japanese Patent No. 4588784 JP-A-11-111226

  However, when the knife edge shape processing at the tip of the molybdenum foil is performed by electrolytic polishing as disclosed in Patent Document 1 or the like, the central portion and the end of the tip of the molybdenum foil to which the electrode is attached by welding are also polished and thinned. When the electrode is welded to the molybdenum foil having such a shape by, for example, resistance heating welding, there is a problem that the molybdenum foil is easily broken during welding. If the welding strength is reduced, the occurrence of breakage can be suppressed, but in that case, there is a possibility that a failure of the welding will be induced.

  Further, as another problem, the thickness of the central portion of the tip of the molybdenum foil changes sensitively depending on various conditions such as the position, concentration and temperature of the electrolytic polishing liquid, and the shape of the molybdenum foil. Therefore, variation in shape such as the thickness of the molybdenum foil is increased. Moreover, there is a problem that the number of man-hours for managing the manufacturing process for managing these process conditions increases.

  Therefore, in the present invention, in a molybdenum foil that has been processed into a knife edge shape by electropolishing, the molybdenum foil in the vicinity of the joint with the electrode becomes too thin. The purpose is to solve the problem of variation in depth. Accordingly, an object is to enable stable production of a high-pressure discharge lamp, improvement of performance, and improvement of reliability.

  The first aspect of the present invention is a molybdenum foil used for electrode mounting of a high pressure discharge lamp. The molybdenum foil has a longitudinal direction and a transverse direction, and has a base portion and a distal end portion that extends from the base portion in the longitudinal direction to form a distal end. The tip portion has a tip edge end portion and a tip center portion extending adjacent to each other in the longitudinal direction, an outer edge portion of the tip edge end portion has a knife edge shape, and a boundary between the tip edge end portion and the tip center portion In the portion, the thickness of the central portion of the tip is larger than the thickness of the tip edge portion.

  According to the said structure, since the front-end | tip center part which welds an electrode is thickened, the fracture | rupture of molybdenum foil in the process of welding an electrode to molybdenum foil is suppressed. In addition, by suppressing the breakage of the molybdenum foil, it is possible to sufficiently increase the strength of welding, and to prevent defects in welding detachment.

  The thickness of the central portion of the tip of the molybdenum foil is preferably substantially the same as the thickness of the base portion. By defining the thickness as described above, the molybdenum foil can sufficiently suppress breakage in the welding process.

  You may make it the boundary part of a front-end | tip center part and a front-end | tip edge edge part be formed in parallel with a longitudinal direction. Moreover, the front-end | tip center part may have a taper shape which becomes thin toward the front end side regarding a longitudinal direction. Still further, the boundary between the tip center portion and the tip edge portion may have a convex portion protruding in the short direction or a concave portion cut in the short direction. By forming the boundary between the tip center and the tip edge in parallel to the longitudinal direction, and making the width of the tip center uniform in the longitudinal direction, the shape of the electrode and the shape of the tip center of the molybdenum foil are Match and facilitate processing. In addition, by forming the center of the tip into a tapered shape that becomes narrower toward the tip, cracking of the quartz glass at the edge near the tip can be prevented during processing of the high-pressure discharge lamp. Furthermore, the boundary between the tip center and the tip edge has a convex part protruding in the short direction or a concave part cut in the short direction, so that the molybdenum foil and the quartz glass are processed during the processing of the high-pressure discharge lamp. The contact area at the boundary of the is increased. As a result, the adhesion between the molybdenum foil and the quartz glass is improved, and the sealing performance is improved.

  The second aspect of the present invention is an electrode mount for a high pressure discharge lamp. The electrode mount includes the molybdenum foil on the first side surface and a tungsten electrode welded to the center of the tip of the molybdenum foil. Still further, the electrode mount comprises a lead wire connected to the base of the molybdenum foil. With this configuration, it is possible to provide an electrode mount that follows the effects obtained with the molybdenum foil on the first side surface.

  The third aspect of the present invention is a high pressure discharge lamp. The high pressure discharge lamp includes a quartz glass arc tube having a discharge space and a sealing portion, and the electrode mount on the second side surface embedded in the sealing portion, and the discharge space is sealed with molybdenum foil. As described above, the high-pressure discharge lamp having such a configuration solves the problems of breakage and welding failure during welding, so that stable production, improved performance, and improved reliability can be realized. By welding the electrode to the thick part of the molybdenum foil, there is an effect that the molybdenum foil is prevented from being broken and disconnected.

  The fourth aspect of the present invention is a covering member for protecting a part of the molybdenum foil when processing the molybdenum foil used for sealing the high-pressure discharge lamp. The covering member has a longitudinal direction and a short side direction, and has a covering base part, a covering tip part extending in the longitudinal direction from the covering base part to form a tip, and a covering tip part having a shorter width direction than the covering base part. By performing the electrolytic polishing step with the covering member sandwiching the front and back surfaces of the molybdenum foil, the center portion of the tip is not polished, so that the molybdenum foil described in the first aspect of the present invention can be processed. In addition, since the thickness of the central portion of the tip can be prevented from varying depending on the electrolytic polishing process conditions, the process management becomes easy, and as a result, the high-pressure discharge lamp can be stably produced.

  The width in the short direction of the coating tip may be constant, may have a tapered shape that becomes narrower toward the tip with respect to the longitudinal direction, or may be a convex or short protruding in the short direction. You may make it have the recessed part cut in the direction. By performing electropolishing with such a shape of the covering member, the shape of the end edge portion of the molybdenum foil after electropolishing can be processed into the same shape as the shape of the covering member. Molybdenum foil having the effect described in the side can be manufactured.

  The material of the covering member is preferably a material that is hardly soluble in the electrolytic polishing liquid. In particular, a material that is hardly soluble in phosphoric acid is preferable. Specifically, a nonmetallic material such as a resin is preferable, and more specifically, a fluororesin, a vinyl chloride resin, a xylene resin, or the like can be used. By using these materials, it is possible to prevent the covering member itself from being polished and dissolved in the electrolytic polishing step, and thus the function of the covering member to protect the molybdenum foil from the electrolytic polishing liquid can be realized.

It is a figure which shows the high pressure discharge lamp which concerns on the Example of this invention. It is a top view of the molybdenum foil which concerns on the Example of this invention. It is the longitudinal direction top view seen from the outer edge part side of the molybdenum foil which concerns on the Example of this invention. It is the transversal direction top view which looked at the molybdenum foil which concerns on the Example of this invention from the front end side. FIG. 3 is a cross-sectional view taken along line A-A ′ to D-D ′ in FIG. 2. It is a schematic diagram of the electropolishing process according to the embodiment of the present invention. It is a figure which shows the coating | coated member which concerns on the Example of this invention. It is a schematic diagram which shows the state which clamped both the front and back of molybdenum foil with the coating | coated member of this invention. It is a figure which shows the coating | coated member by the 1st modification. It is a figure which shows the upper side figure of the molybdenum foil produced using the coating | coated member of the 1st modification. It is a figure which shows the coating | coated member by the 2nd modification. It is a figure which shows the upper side figure of the molybdenum foil produced using the coating | coated member of the 2nd modification.

<Example>
FIG. 1 shows a high-pressure discharge lamp 1 according to an embodiment of the present invention. The high-pressure discharge lamp 1 includes a quartz glass arc tube 2 (hereinafter referred to as “arc tube 2”) and a pair of electrode mounts 8 included therein. The arc tube 2 includes a discharge space 3 and a pair of sealing portions 4 sandwiching the discharge space 3. Each electrode mount 8 includes a tungsten electrode 5 (hereinafter referred to as “electrode 5”) and a molybdenum foil 6 that are welded to each other by resistance heating welding. And a lead wire 7. The outer surface shape of the quartz glass portion that defines the discharge space 3 is a spheroid shape having a maximum outer diameter of 10 mm, and is a shape close to a sphere. The inner surface shape of the quartz glass portion defining the discharge space 3 is a spheroid elongated in the axial direction of the high-pressure discharge lamp 1, and the internal volume is 0.8 ml. The electrode 5 includes an electrode shaft and a coil portion, and the electrode shaft is a bar made of pure tungsten having a diameter of 0.40 mm. The coil portion is configured by double winding a pure tungsten wire having a diameter of 0.20 mm around the tip end portion of the electrode shaft by close winding, and the tip end portion of the coil portion is welded and integrated with the electrode shaft. . The tip side of the electrode 5 is exposed to the discharge space 3 of the arc tube 2, and a part of the base side of the electrode 5, a part of the molybdenum foil 6 and the lead wire 7 are embedded in the sealing part 4. The discharge space 3 is filled with 0.20 mg / mm ³ or more of mercury, rare gas, and halogen gas, and the mercury vapor pressure during lighting becomes 200 atmospheres or more. In the present specification, the drawings are not drawn to scale, and the feature portions are drawn with emphasis.

  FIG. 2 shows a top view of the molybdenum foil 6 according to the embodiment of the present invention. In the following description, the long side direction (left-right direction in FIG. 2) of the molybdenum foil 6 is referred to as the longitudinal direction, the short side direction (vertical direction in FIG. 2) is referred to as the short side direction, and the depth direction in FIG. Let's say direction. In FIG. 2, the molybdenum foil 6 has a base portion 10 and a tip portion 12 that extends from the base portion 10 in the longitudinal direction to form a tip, and the base portion 10 and the tip portion 12 are parallel to the short direction. 14a. The distal end portion 12 has a distal end edge portion 16 and a distal end central portion 18 extending adjacent to each other in the longitudinal direction, and the distal end edge end portion 16 and the distal end central portion 18 are separated by a boundary portion 14b parallel to the longitudinal direction. It is done. Here, in the boundary portion 14 b, the tip center portion 18 is thicker than the tip edge portion 16.

  The distal end edge 16 has an outer edge 17 composed of a longitudinal outer edge 17a on the side surface side and a lateral outer edge 17b on the distal side. The outer edge portion 17 is processed into a knife edge shape by an electrolytic polishing process. In this embodiment, the end portion 11 of the base portion 10 is processed into a knife edge shape, but the end portion 11 may not be processed into a knife edge. The end portion 19 of the tip center portion 18 is not subjected to electrolytic polishing and has a flat shape. In the manufacturing process of the electrode mount 8, the electrode 5 is attached to the tip center portion 18 that is not electropolished by welding. Since the tip center portion 18 is not subjected to electrolytic polishing, the thickness thereof is ensured.

  As described above, in the molybdenum foil 6 of this embodiment, the thickness of the tip center portion 18 is ensured, thereby preventing breakage in the welding process. Moreover, by ensuring the thickness of the front end central portion 18, it is possible to sufficiently increase the strength of welding, and defects in welding detachment are suppressed.

  The feature of the shape of the molybdenum foil 6 of the present invention will be described in more detail using a plan view and a sectional view. FIG. 3 is a plan view of the molybdenum foil 6 when viewed from the longitudinal outer edge portion 17a side with the longitudinal direction as the left and right direction of the drawing, the short direction as the depth direction of the drawing and the thickness direction as the up and down direction of the drawing. FIG. 4 is a plan view of the molybdenum foil 6 when viewed from the end 19 side with the short side direction being the left-right direction of the paper, the longitudinal direction being the depth direction of the paper surface, and the thickness direction being the vertical direction of the paper surface. FIG. 5 is a cross-sectional view taken along lines A-A ′ to D-D ′ in FIG. 2.

  In the present embodiment shown in FIGS. 3, 4, and 5, since the tip center portion 18 is not subjected to electrolytic polishing, the thickness thereof is equal to the initial thickness (T1) at the time of preparation of the molybdenum foil 6. In the present embodiment, the thickness of the tip 19 of the tip center 18 is also T1. On the other hand, the tip edge portion 16 is subjected to electrolytic polishing to have a knife edge shape, and the maximum thickness portion thereof is T2 smaller than T1. Thus, the thickness of the tip center portion 18 is larger than the thickness of the tip edge portion 16 in the boundary portion 14b. In addition, also in the boundary part 14a, the thickness of the base 10 is larger than the thickness of the front-end edge part 16. FIG.

  A method for manufacturing the molybdenum foil 6 according to an embodiment of the present invention will be described. First, a method for processing the molybdenum foil 6 into a predetermined strip shape will be described. First, a long molybdenum foil material is prepared. The strip-shaped molybdenum foil 6 processed into a predetermined external dimension is obtained by cutting this using a cutter, a laser processing machine, or the like in the short direction so as to have a predetermined length. The dimensions of the molybdenum foil 6 processed into a strip shape are, for example, a length (longitudinal direction) of 13.5 mm, a width (short direction) of 1.5 mm, and a thickness (thickness direction) of 20 μm. The corners of the two corners of the front end portion 12 of the molybdenum foil 6 can be chamfered into a linear shape or a curved shape. Therefore, you may perform the cutting process for chamfering at this time. By chamfering, the adhesion between the molybdenum foil 6 and the quartz glass is improved during sealing in the manufacturing process of the high-pressure discharge lamp 1, and the pressure resistance performance is improved. The long molybdenum foil material may be procured that has been processed to have a knife edge shape at the end in advance. In this case, at the time of procurement, the end of the long side of the molybdenum foil 6 has a knife edge shape, and the end (cut surface) and the chamfered portion in the short direction are not in the shape of a knife edge.

  Next, of the cut surface of the molybdenum foil 6, the end portion 19 of the tip center portion 18 is not subjected to electrolytic polishing, and only the outer edge portion 17 of the tip edge portion 16 is formed into a knife edge shape by electrolytic polishing. FIG. 6 shows a schematic diagram of an electropolishing apparatus 30 according to the present embodiment. The electropolishing apparatus 30 includes an electropolishing tank 32, an electropolishing liquid 38 accommodated in the electropolishing tank 32, a copper plate 34 used as a cathode during electropolishing, a molybdenum foil 6 used as an anode and electropolished, a cathode and an anode, A direct current source 36 having a negative electrode and a positive electrode for connection is provided. The molybdenum foil 6 is covered with a covering member 40.

  FIG. 7 shows a top view of the covering member 40, and FIG. 8 shows a bird's-eye view of the covering member 40 with the molybdenum foil 6 sandwiched therebetween. The covering member 40 includes a covering base 41 and a covering tip 42 that extends from the covering base 41 in the longitudinal direction and forms a tip. The length of the covering tip portion 42 in the short direction is shorter than the length of the covering base portion 41 in the short direction. As described above, the covering member 40 is processed into a shape that covers the portion other than the tip edge 16 of the molybdenum foil 6, that is, the tip center 18 and the base 10.

  Electropolishing is performed as follows. First, an electrolytic polishing liquid 38 is prepared in the electrolytic polishing tank 32. As the electrolytic polishing liquid 38, an acidic aqueous solution such as a 10% diluted aqueous solution of phosphoric acid is used. Next, the copper plate 34 and the molybdenum foil 6 to be processed into a positive electrode are connected to the negative electrode of the direct current source 36, and these are immersed in the electrolytic polishing liquid 38, and then the direct current voltage required for the electrolytic polishing from the direct current source 36 (for example, 20V) is applied. Here, one end of the molybdenum foil 6 to which the electrode 5 is connected in a later welding process is immersed in the electrolytic polishing liquid 38, and the other end is not immersed but connected to the anode of the direct current source 36.

  The front and back surfaces of the molybdenum foil 6 are immersed in the electrolytic polishing liquid 38 with the covering member 40 sandwiched. As a result, the portion of the molybdenum foil 6 covered with the covering member 40 does not directly contact the electrolytic polishing liquid 38, and only the portion not covered with the covering member 40 contacts the electrolytic polishing liquid 38. Therefore, in this electropolishing process, only the front end edge 16 is electropolished, and the portion including the outer edge 17 is processed into a knife edge shape. In this step, the application time of the voltage supplied from the direct current source 36, the temperature of the electrolytic polishing liquid 38, and the like are appropriately set to optimum values, whereby the shape of the knife edge of the outer edge portion 17 of the molybdenum foil 6 and It is possible to adjust the angle.

  The material of the covering member 40 is preferably hardly soluble in an acidic solution such as phosphoric acid used as the electropolishing liquid 38. Specifically, it is preferable to use a non-metallic material such as resin (fluororesin, vinyl chloride resin, xylene resin) or glass. By using such a hardly soluble material, the molybdenum foil 6 can be protected from the electrolytic polishing liquid 38 without the covering member 40 being dissolved in the electrolytic polishing liquid 38. Furthermore, these materials such as resin or glass are preferable in that they are low in cost and can be easily processed into various shapes.

  The electrode 5 is welded in parallel with the longitudinal direction on the front end central portion 18 of the molybdenum foil 6 manufactured as described above, and the lead wire 7 is connected to the base 10 near the end opposite to the front end central portion 18. Is done. Thereby, the electrode mount 8 is formed. And the electrode mount 8 is embed | buried under the sealing part 4 of the arc tube 2, and the high pressure discharge lamp 1 is produced by sealing the discharge space 3 with molybdenum foil.

  As described above, by covering the both surfaces of the molybdenum foil 6 with the covering member 40 and performing electrolytic polishing, the outer edge portion 17 of the tip edge end portion 16 is processed into a knife edge shape, and the tip center portion 18 and its end portion are processed. No. 19 can be processed to maintain the original thickness without being polished. By using the molybdenum foil 6 processed in this way, there is an effect that the molybdenum foil 6 is hardly broken when the electrode 5 is welded in the manufacturing process of the high-pressure discharge lamp 1. Further, since the molybdenum foil 6 is difficult to break, the welding strength of the electrode 5 can be sufficiently increased, and defects in the welding failure are reduced. Therefore, according to the present invention, it is possible to improve the performance and the reliability of the high-pressure discharge lamp 1.

  In addition, since the tip center portion 18 of the molybdenum foil 6 is not electropolished in the present embodiment, the shape such as thickness does not vary due to the electropolishing process. That is, since it is not affected by various process conditions such as the position, concentration and temperature of the electrolytic polishing liquid 38 and the shape of the molybdenum foil, stable production becomes possible, and furthermore, these process conditions are managed. Management man-hours are reduced.

<Modification>
The shape of the covering member 40 and the molybdenum foil 6 processed using the covering member 40 is not limited to the shape described above, and various modifications are possible. For example, FIGS. 9 and 10 show a covering member 40 according to a first modification and a molybdenum foil 6 formed using the covering member 40, respectively. As shown in FIG. 9, the covering member 40 includes a covering base 41 and a tapered covering tip 43 that extends from the covering base 41 in the longitudinal direction and becomes thinner toward the tip. In FIG. 9, the shape of the end portion 44 of the covering tip portion 43 is linear, but it may be curved. By forming the covering member 40 in such a tapered shape, as shown in FIG. 10, the tip center portion 18 of the electropolished molybdenum foil 6 corresponds to the tapered shape of the covering tip portion 43 of the covering member 40. It is processed into a tapered shape that becomes thinner toward the tip side. Thereby, according to the taper shape of the coating | coated front-end | tip part 43 of this coating | coated member 40, the process of cutting the corner | angular part of the molybdenum foil 6 and chamfering the corner | angular part of the molybdenum foil 6 can also be added.

  11 and 12 show a covering member 40 according to a second modification and a molybdenum foil 6 formed using the covering member 40, respectively. As shown in FIG. 11, the covering member 40 includes a covering base 41 and a covering tip 45 extending from the covering base 41 in the longitudinal direction. The edge part of the coating | coated front-end | tip part 45 has the convex part 46a which protrudes in a transversal direction, and the recessed part 46b cut in the transversal direction. In this modification, a plurality of convex portions 46a and concave portions 46b are provided on both sides in the longitudinal direction of the covering tip portion 45, and a zigzag shape is formed. By forming the covering member 40 in such a zigzag shape, as shown in FIG. 12, the boundary portion 14d of the tip center portion 18 after electrolytic polishing also has a zigzag shape having a concave portion and a convex portion. The zigzag shape may be a smooth wave shape or a rectangular uneven shape. Moreover, these unevenness | corrugations do not need to be periodic and may consist of one convex part or one concave part. As described above, since the edge of the coating tip 45 is formed in a zigzag shape, the contact area at the boundary between the molybdenum foil 6 and the quartz glass is increased when the high-pressure discharge lamp 1 is processed. Thereby, the adhesive force between the molybdenum foil 6 and the quartz glass is improved, and the pressure resistance performance is improved.

  In the above-described embodiments and modified examples, the tip 12 and the covering tip 42, 43, or 45 are configured to be symmetrical in the lateral direction, but the tip 12 and the covering tip 42 are symmetrical. Not limited. For example, the coating front end portion 42, 43 or 45 may have a shape that exposes both the front end edge portions 16 (outer edge portions 17).

DESCRIPTION OF SYMBOLS 1 High pressure discharge lamp 2 Quartz glass arc tube 3 Discharge space 4 Sealing part 5 Tungsten electrode 6 Molybdenum foil 7 Lead wire 8 Electrode mount 10 Base part 12 Tip part 14a, 14b, 14c, 14d Boundary part 16 Tip edge part 17 Outer edge Portion 18 End central portion 40 Cover member 41 Cover base 42, 43, 45 Cover tip 46a Convex 46b Concave

Claims (17)

Molybdenum foil used for electrode mounting of high-pressure discharge lamps,
The molybdenum foil has a longitudinal direction and a lateral direction, and has a base portion and a distal end portion that extends from the base portion in the longitudinal direction to form a distal end.
The tip has a tip edge end and a tip center extending adjacent to the longitudinal direction, an outer edge of the tip edge has a knife edge shape, and the tip edge and the tip Molybdenum foil in which the thickness of the center of the tip is larger than the thickness of the edge of the tip at the boundary of the tip center. Molybdenum foil used for electrode mounting of high-pressure discharge lamps,
The molybdenum foil has a longitudinal direction and a lateral direction, and has a base portion and a distal end portion that extends from the base portion in the longitudinal direction to form a distal end.
The tip has a tip edge end and a tip center extending adjacent to the longitudinal direction, an outer edge of the tip edge has a knife edge shape, and the tip edge and the tip A molybdenum foil, wherein a thickness of the tip central portion is larger than a thickness of the tip edge end portion, and a thickness of the tip center portion is substantially the same as a thickness of the base portion at a boundary portion of the tip center portion.   The molybdenum foil according to claim 1 or 2, wherein a boundary portion between the tip center portion and the tip edge end portion is formed in parallel to the longitudinal direction.   The molybdenum foil according to claim 1 or 2, wherein the tip center portion has a tapered shape that becomes narrower toward the tip side in the longitudinal direction.   3. The molybdenum foil according to claim 1, wherein the boundary portion between the tip center portion and the tip edge end portion has a convex portion protruding in the short-side direction or a concave portion cut in the short-side direction. An electrode mount for a high-pressure discharge lamp,
Molybdenum foil according to any one of claims 1 to 5,
The electrode mount provided with the tungsten electrode welded to the said front-end | tip center part of the said molybdenum foil. An electrode mount for a high-pressure discharge lamp,
Molybdenum foil according to any one of claims 1 to 5,
A tungsten electrode welded to the center of the tip of the molybdenum foil;
An electrode mount comprising a lead wire connected to the base of the molybdenum foil. A high pressure discharge lamp,
A quartz glass arc tube having a discharge space and a sealing portion;
A high pressure discharge lamp comprising: the electrode mount according to claim 7 embedded in the sealing portion, wherein the discharge space is sealed with the molybdenum foil. A covering member for protecting a part of the molybdenum foil when processing the molybdenum foil used for sealing the high-pressure discharge lamp,
The covering member has a longitudinal direction and a short direction, a covering base, and a tip extending from the covering base in the longitudinal direction to form a tip, and a covering tip having a shorter width direction than the covering base. A covering member having. A covering member for protecting a part of the molybdenum foil when processing the molybdenum foil used for sealing the high-pressure discharge lamp,
The covering member has a longitudinal direction and a short direction, a covering base, and a tip extending from the covering base in the longitudinal direction to form a tip, and a covering tip having a shorter width direction than the covering base. A covering member having a uniform shape with respect to the longitudinal direction. A covering member for protecting a part of the molybdenum foil when processing the molybdenum foil used for sealing the high-pressure discharge lamp,
The covering member has a longitudinal direction and a short direction, a covering base, and a tip extending from the covering base in the longitudinal direction to form a tip, and a covering tip having a shorter width direction than the covering base. A covering member having a tapered shape in which the covering tip end portion becomes narrower toward the tip end side with respect to the longitudinal direction. A covering member for protecting a part of the molybdenum foil when processing the molybdenum foil used for sealing the high-pressure discharge lamp,
The covering member has a longitudinal direction and a short direction, a covering base, and a tip extending from the covering base in the longitudinal direction to form a tip, and a covering tip having a shorter width direction than the covering base. A covering member having a convex portion protruding in the short-side direction or a concave portion cut in the short-side direction.   The covering member according to any one of claims 9 to 12, comprising a material that is hardly soluble in an acidic solution.   The covering member according to claim 13, which is made of a material that is hardly soluble in an acidic solution containing phosphoric acid.   The covering member according to claim 14 which consists of nonmetallic materials.   The covering member according to claim 15 which consists of resin.   The covering member according to claim 16, comprising one or more materials selected from the group consisting of a fluororesin, a vinyl chloride resin, and a xylene resin.

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