JP2007273174A - Electrode for high-pressure discharge lamp, manufacturing method of the electrode, and process of manufacturing method of high-pressure discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing at low cost an electrode with high light-extraction efficiency. <P>SOLUTION: The electrode 9 is formed through a forming process of forming an electrode preliminary 52 by overlapping three layers of preliminary coil parts 56a, 56b, 56c made by winding metal wires in a coil shape around a tip part 50a of an axis rod 50, and a melting process of heating and melting a tip part 54 of the electrode preliminary 52 and tapering off a shape of the tip part 54. In the forming process, the three-layer preliminary coil parts 56a, 56b, 56c are overlapped with a tip-side end part of a k-th-layer preliminary coil part (k being a natural number of 2 or more) at an interval of 1.5-piece portion of the metal wire constituting a (k-1)th-layer preliminary coil part toward a rear-end side in an extension direction of the axis rod 50 from a tip-side end part of the (k-1)th-layer preliminary coil part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrode for a high-pressure discharge lamp, a method for manufacturing the electrode, and a method for manufacturing a high-pressure discharge lamp.

A high-pressure discharge lamp (hereinafter simply referred to as “lamp”) includes a discharge vessel having a discharge space therein and a pair of electrodes held in the discharge vessel in a state of facing each other in the discharge space. . Such a high-pressure discharge lamp has a so-called short arc type in which the distance between the electrodes is short, and is used as a light source of a display device such as a liquid crystal projector.
FIG. 11 is an enlarged view of a pair of electrodes for a conventional short arc lamp.

As shown in FIG. 11, the electrodes 901 and 903 include electrode shafts 905 and 907, and winding portions 909 and 911 formed by winding a metal wire in a coil shape around the tip portions of the electrode shafts 905 and 907. The tip portions 913 and 915 of the electrode shafts 905 and 907 and the winding portions 909 and 911 are processed into a hemisphere by heating and melting (for example, Patent Document 1).
A lamp provided with the electrodes 901 and 903 has a problem that light extraction efficiency is poor. That is, as shown in the figure, among the light emitted from the substantially center O1 between the pair of electrodes 901 and 903, the light emitted toward the range of the angle θ1 is emitted from the discharge space to the outside. On the other hand, for example, light radiated outside the range of the angle θ1 (indicated by arrow A in the figure) is blocked by the tip 913 of the hemispherical electrode 901 and is not emitted from the discharge vessel to the outside. It is.

As a technique for improving the light extraction efficiency by enlarging the angle θ1, the tip shape of the electrode is, for example, an electrode 921, with tip portions 925 and 927 having frustoconical shapes as shown in FIG. 923 (for example, Patent Document 2). In the electrodes 921 and 923 in which the tip portions 925 and 927 have a frustoconical shape, light emitted toward a range of an angle θ2 wider than the angle θ1 is emitted from the substantially center O2 between them. Therefore, the light extraction efficiency is improved as compared with an electrode having a hemispherical tip.
JP 2002-83538 A JP 2002-93363 A

The electrodes 921 and 923 having the truncated conical shapes of the tip portions 925 and 927 are machined, for example, from one tungsten rod by machining. However, since tungsten is difficult to machine and expensive, there is a problem that it results in an expensive electrode.
The present invention has been made in view of the above problems, a manufacturing method capable of manufacturing an electrode with high light extraction efficiency at low cost, a manufacturing method capable of manufacturing a high pressure discharge lamp with high light extraction efficiency at low cost, and An object of the present invention is to provide an electrode for a high-pressure discharge lamp that can increase the light extraction efficiency and is relatively inexpensive.

  In order to achieve the above object, an electrode manufacturing method according to the present invention is a method for manufacturing an electrode for a high-pressure discharge lamp, wherein a coil portion is formed by winding a metal wire in a coil shape around a tip portion of a shaft rod. Are formed by overlapping n layers (n is a natural number of 2 or more) to form an electrode preliminary body, and a melting step of heating and melting the tip of the electrode preliminary body in a tapered manner. The coil position of the k-layer (k is a natural number equal to or less than n and a natural number equal to or greater than 2) is the end position on the tip side of the coil section of the k-1th layer. To the rear end side in the extending direction of the shaft rod, and is stacked in a state of being separated by one or more metal wires constituting the coil portion of the k-1th layer.

The term “tapered” as used herein refers not only to the case where the melted portion tapers as it moves from the rear end to the front end on the shaft rod, but also when the molten portion moves from the rear end to the front end portion on the shaft. Including the case of becoming thicker and then tapering.
Further, in the forming step, after the n-th coil portion, which is the outermost layer, is overlapped, a second metal wire constituting the coil portion and straddling the metal wire adjacent to the longitudinal direction of the shaft rod is formed. A second coil part formed by winding a metal wire is overlapped, and an outer peripheral diameter of the second coil part is equal to or smaller than an outer peripheral diameter of the n-th coil part, or the formation In the process, before the coil portion of the k-th layer is overlapped, a third metal wire is formed across the metal wire constituting the coil portion of the (k-1) -th layer and adjacent to the longitudinal direction of the shaft rod. The wound third coil portion is overlapped, and the metal wire of the third coil portion is composed of a metal wire constituting the k-1 layer coil portion and a metal constituting the k layer coil portion. It is characterized by a size that fits in the gap with the line.

Further, after the forming step, a fixing step of fixing each coil portion to the shaft rod is performed by heating and melting a rear end portion of each coil portion opposite to the tip.
On the other hand, in order to achieve the above object, a method for manufacturing a high-pressure discharge lamp according to the present invention includes an electrode manufacturing process for manufacturing an electrode and a sealing process for sealing the electrode manufactured in the process to a discharge vessel. In the electrode manufacturing process, the electrode manufacturing method described above is performed.

  On the other hand, in order to achieve the above object, the electrode for a high-pressure discharge lamp according to the present invention has a coil portion formed by winding a metal wire in a coil shape at the tip of a shaft rod, where n is a natural number of 2 or more. ) The electrodes for the high-pressure discharge lamp are stacked and the tips of the n-layered coil portions are heated and melted so that the entire tips of the n-layered coil portions have a conical shape. The angle between the cone axis and the generatrix is 30 degrees or less.

  In addition, a metal wire that constitutes the n-th layer coil portion and includes a second coil portion in which a second metal wire is wound across a metal wire adjacent to the extending direction of the shaft rod, The outer diameter of the second coil portion is less than or equal to the outer diameter of the n-th coil portion, or the k-1th layer (k is a natural number of n or less and a natural number of 2 or more) ) Including a third coil portion formed by winding a third metal wire across a metal wire adjacent to the longitudinal direction of the shaft rod. The metal wire of the coil part is characterized by having a size that fits into a gap between the metal wire constituting the coil part of the (k-1) th layer and the metal wire constituting the coil part of the kth layer.

In the electrode manufacturing method according to the present invention, since the tip of the electrode preliminary body is tapered at the stage of forming the electrode preliminary body, if the tip of the electrode preliminary body is melted as it is, a tapered electrode is obtained. A tapered electrode can be easily manufactured.
Further, when forming the electrode preliminary body, the position of the end portion on the tip side of the k-th layer (k is a natural number of 2 or more) coil portion is set to the end portion on the tip side of the k-th layer coil portion. By adjusting with respect to this, an arbitrary tapered electrode preliminary body can be obtained, and as a result, the tip shape of the electrode can be easily formed into an arbitrary tapered shape.

In addition, since this manufacturing method uses a forming step and a melting step, for example, a conventional electrode manufacturing technique in which a metal wire is wound around a shaft rod in a coil shape and the tip of the electrode preliminary body is melted. An electrode manufacturing apparatus can be used.
Moreover, since the manufacturing method of the high pressure discharge lamp which concerns on this invention utilizes the manufacturing method of the said electrode, as a result, a high pressure discharge lamp with high light extraction efficiency can be manufactured cheaply.

  Furthermore, the electrode for a high-pressure discharge lamp according to the present invention has an angle between the generatrix of the conical tip and the axis of the conical portion of 30 degrees or less, so the above-described manufacturing method can be utilized, The extraction efficiency can be increased, and it can be manufactured at a low cost.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
1. Configuration of High-Pressure Mercury Lamp FIG. 1 is a diagram illustrating a configuration of a high-pressure mercury lamp according to the first embodiment.
The high-pressure mercury lamp (hereinafter simply referred to as “lamp”) 1 is a kind of high-pressure discharge lamp, and is a so-called short arc type used as a light source of a display device such as a liquid crystal projector. In the discharge space 5 inside the discharge vessel 3, the lamp 1 opposes the pair of electrodes 7 and 9 with a predetermined distance (so-called “interelectrode distance”) as shown in FIG. As described above, each has a structure extending from the sealing portions 11 and 13 on both sides of the discharge space 5 to the inside of the discharge space 5.

  The discharge vessel 3 is made of, for example, quartz glass, and a main tube portion 6 having a substantially spheroid shape at the center, and sealing portions 11 and 13 extending outward from both sides of the main tube portion 6. Is provided. The pair of electrodes 7 and 9 are connected to external lead wires 27 and 29 made of, for example, molybdenum via foils 23 and 25 made of, for example, molybdenum sealed in the sealing portions 11 and 13 of the discharge vessel 3. (This connected structure is called an “electrode structure”.) For example, welding is used to connect the foils 23 and 25 and the electrodes 7 and 9 and the foils 23 and 25 and the external lead wires 27 and 29.

The inter-electrode distance between the pair of electrodes 7 and 9 should be set to 1.5 mm or less in order to improve the light extraction efficiency of the lamp 1 and improve the luminance on the screen surface. More preferably, it is more preferably set in the range of 0.5 mm to 1.5 mm.
In addition, the manufacturing method of the electrode which concerns on this invention is naturally applicable not only to the electrode used for the lamp | ramp whose distance between electrodes is 1.5 mm or less but to the electrode of the lamp | ramp whose distance between electrodes is larger than 1.5 mm.

Inside the discharge space 5, mercury 31 as a luminescent material, rare gas such as argon, krypton, and xenon for starting assistance, and halogen such as iodine and bromine for halogen cycle are enclosed.
FIG. 2 is an enlarged view of the electrode, (a) is an external view of the electrode, and (b) is a longitudinal sectional view of the electrode. Since the electrode 7 has the same structure as the electrode 9, an enlarged view of the electrode 7 is omitted.

  As shown in FIGS. 1 and 2, the electrodes 7 and 9 are formed by, for example, winding a tungsten wire around the tip end portions (one end portions) of shaft rods to be electrode shafts 15 and 17 made of tungsten, for example. 19 and 21 are provided to form an electrode preliminary body, which will be described later, and the tip portion of the electrode preliminary body is heated and melted by so-called electric discharge machining to form the tip portions 20 and 22 in a tapered shape. Is obtained. A method for manufacturing the electrodes 7 and 9 will be described later.

The electrode winding portions 19 and 21 are each composed of three layers of electrode coil portions 19a, 19b, and 19c as shown in FIG. The three-layered electrode coil portions 19a, 19b, and 19c are wound in a coil shape at the same pitch using the same type (diameter and material) of metal wires.
Here, in the three-layer electrode coil portions 19a, 19b, and 19c, the first-layer electrode coil portion 19a is on the electrode shaft 15 side, that is, the innermost layer side, and the third-layer electrode coil portion 19c is on the outermost layer side. is there. That is, in the case of a plurality of layers, the closer the alphabet after 19 is to “a”, the closer to the electrode axes 15 and 17.

The metal wire of the second-layer electrode coil portion 19b has the same pitch as that of the first electrode coil portion 19a so as to straddle both metal wires adjacent in the longitudinal direction of the electrode shaft 15 in the first-layer electrode coil portion 19a. And it is wound around the outer peripheral surface of the 1st electrode coil part 19a in the same direction.
In addition, the metal wire of the third-layer electrode coil portion 19c is the same as the second electrode coil portion 19b so as to straddle both metal wires adjacent in the longitudinal direction of the electrode shaft 15 in the second-layer electrode coil portion 19b. It is wound around the outer peripheral surface of the second electrode coil portion 19b in the pitch and in the same direction.

As shown in FIG. 2, the tip of the electrode 9 has a tapered shape, specifically a conical shape, and corresponds to the generatrix B1 and a conical axis (here, the axis of the electrode shaft 15). ) The angle C1 to 15a is 30 degrees. Note that the conical tip is rounded due to processing, but in this case as well, it is considered that it is conical as a whole.
For example, as shown in FIG. 3, the lamp 1 having the above configuration is incorporated in a reflecting mirror 44 with a base 42 attached to one sealing portion, here, the sealing portion 13, and includes the lamp 1. The unit 46 is configured and used as a light source of the liquid crystal projector in this state. The reflecting mirror 44 and the base 42 are fixed to each other through a cement 48, for example.

2. Electrode Manufacturing Method FIG. 4 is a diagram for explaining an electrode manufacturing process.
Since the electrode 9 has the same configuration as the electrode 7, the manufacturing process of the electrode 9 will be described below.
The electrode 9 has an N layer (N is a natural number of 2 or more) of a preliminary coil portion formed by densely winding a metal wire in a coil shape on the tip portion 50a of the shaft 50 shown in FIG. 4 (b), the step of forming the electrode preliminary body 52 having a tapered tip portion shape, and the front end portion 54 of the electrode preliminary body 52 is heated and melted, and shown in FIG. 4 (c). It is manufactured through a melting step in which the shape of the tip portion 20 is tapered.

(1) Forming Step As shown in FIG. 4A, the electrode preliminary body 52 is formed by, for example, applying a tungsten metal wire having a wire diameter of 0.2 mm to a tungsten shaft rod 50 having a wire diameter of 0.4 mm, for example. The preliminary body winding portion 56 is formed by dense winding. The shaft 50 becomes the electrode shaft 15 when completed as the electrode 9, and the spare body winding part 56 becomes the electrode winding part 19 when completed as the electrode 9.

FIG. 5A is a diagram showing an electrode preliminary body, and FIG. 5B is a longitudinal sectional view of the electrode preliminary body.
As shown in FIG. 5 (b), the preliminary winding part 56 is composed of three layers of preliminary coil parts 56a, 56b, and 56c wound in a coil shape. The overall shape of the preliminary body winding portion 56 is such that the tip portion 54 is tapered as a whole, and the rear portion 58 of the tip portion 54 is generally cylindrical.

  That is, when the preliminary winding part 56 is cut along a virtual plane passing through the axis of the shaft 50 (corresponding to (b) of FIG. 5), the leading ends of the preliminary coil parts 56a, 56b, and 56c of the respective layers. Since the segment B2 (see FIG. 5A) connecting the outer peripheries of the metal wires 60, 62, and 64 located at the position coincides with the conical bus, the preliminary winding portion 56 has a substantially conical shape. It is regarded as a tapered shape.

  The three-layer preliminary coil portions 56a, 56b, and 56c are wound at the same pitch by using one type (the same diameter, material, etc.) of metal wires. The pitch is a distance between the centers of adjacent metal wires in a direction parallel to the central axis of the coil portion (that is, coincides with the axis of the shaft 50). Here, the adjacent metal wires are in contact with each other. The pitch is the same as the diameter of the metal wire. In addition, the plurality of layers of the preliminary coil portions 56a, 56b, and 56c constituting the preliminary winding portion 56 are closer to the inner layer (closer to the shaft 50) as the number of layers is smaller.

The first layer preliminarily coiled portion 56a is formed by being directly wound around a shaft rod 50, and is configured by winding a metal wire from the tip of the shaft rod 50 to the middle portion thereof. The second-layer spare coil portion 56b is configured to be wound so as to straddle the metal wire adjacent to the longitudinal axis of the shaft 50 on the first-layer spare coil portion 56a.
The metal wire 62 located at one end (tip) of the shaft rod 50 in the second-layer spare coil portion 56b is a metal wire 60 located at one end (tip) of the shaft rod 50 in the first-layer spare coil portion 56a. Are separated from at least one metal wire. That is, in FIG. 5B, the distance D1 between the (first) end of the first-layer metal line 60 and the (first) end of the second-layer metal line 62 is 1.5 metal lines. Equivalent to.

  Similarly to the second-layer spare coil portion 56b, the third-layer spare coil portion 56c also has a metal wire 64 positioned at one end (tip) of the shaft 50 in the third-layer spare coil portion 56c. At least one metal wire is separated from the metal wire 62 located at one end (tip) of the shaft 50 in the second-layer spare coil portion 56b. That is, in FIG. 5B, the distance D2 between the (first) end of the second-layer metal line 62 and the (first) end of the third-layer metal line 64 is 1.5 metal lines. Equivalent to.

As shown in FIG. 5 (a), the electrode preliminary body 52 formed in the above-described forming step is formed of metal wires 60, 62, 64 located at the tips of the preliminary coil portions 56a, 56b, 56c of the respective layers. An angle C2 between the line segment B2 connecting the outer periphery and the axis 50b of the shaft rod 50 is about 30 degrees.
(2) Melting step Next, a melting process for tapering the tip 54 of the electrode preliminary body 52 is performed.

FIG. 6 is a diagram showing an outline of melt processing.
First, as shown in FIG. 6, the distance Dp from the front end of the electrode preliminary body 52 to the front end of the electrode (cathode) 72 of the argon plasma welding apparatus 70 is set and maintained at 1.0 mm, for example, and arc discharge is performed. I do. The tip 54 is melted by this arc discharge, and the conical portion of the tip is completed as shown in FIG. 2B where the electrode 9 having an angle C1 between the bus B1 and the shaft 15a of 30 degrees is completed. . In this melt processing process, it is preferable to carry out by a plurality of intermittent arc discharges and to provide at least one cooling period between the arc discharges. Thereby, compared with the case where the shape is controlled by melting with a single continuous arc discharge, the control is easier to perform, and there is no possibility that cavities are generated in the tip portions 20 and 22.

3. Manufacturing method of lamp The lamp having the above-described configuration includes a container manufacturing process for manufacturing a glass container to be the discharge container 3, an electrode structure manufacturing process for manufacturing an electrode structure, and sealing for sealing the electrode structure to a glass container. And a manufacturing method including a process. In addition, a container manufacturing process and a sealing process are performed by the well-known method conventionally performed.

The electrode structure manufacturing process includes an electrode manufacturing process for manufacturing the above electrode, and an integration process for fixing and integrating the manufactured electrode, foil, and external lead wire. The electrode manufacturing process is the same as described in 2. above. This is as described in the electrode manufacturing method.
In addition, the integration process is performed by, for example, fixing the electrode shaft and the foil, and the foil and the external lead wire by welding in a state where the electrode shaft, the foil, and the external lead wire are aligned. It has become. Thereby, an electrode structure is completed.

<Second Embodiment>
In the first embodiment, the three-layer coil portion is formed using the metal wire having the same diameter, but the electrode coil portion is formed using the metal wire described in the first embodiment. You may provide the subelectrode coil part different from the coil part demonstrated in 1st Embodiment using the metal wire of a different diameter from the said metal wire.

In the second embodiment, since the sub electrode coil portion is formed, the electrode coil portion described in the first embodiment is used as the main electrode coil portion in order to distinguish it from the sub electrode coil portion. And
FIG. 7 is an enlarged view of a partial cross section of the electrode according to the second embodiment.
The electrode 90 according to the second embodiment includes an electrode shaft 15 and an electrode winding portion 91 in which a metal wire is wound around the electrode shaft 15, and includes the electrode shaft 15 and the electrode winding portion 91. The tip has a conical shape that is tapered by melt processing.

The electrode winding portion 91 includes main electrode coil portions 19a, 19b, and 19c (having the same structure as the electrode coil in the first embodiment) wound around the electrode shaft 15, and the main electrode coil portion 19a. , 19b, 19c, and auxiliary electrode coil portions 92a, 92b, 92c wound around the outer periphery.
Here, the configuration of the electrode shaft 15 and the main electrode coil portions 19a, 19b, and 19c, and the melt processing of the tip portion of the electrode preliminary body are the same as those in the first embodiment, and thus description thereof is omitted. The sub electrode coil portions 92a, 92b, and 92c will be described.

  Of the three (three-layer) sub-electrode coil portions, the sub-electrode coil portion 92a is closest to the electrode shaft 15 and the sub-electrode coil portion 92c is At the farthest point, the sub-electrode coil portion 92a is “the first sub-electrode coil portion”, the sub-electrode coil portion 92b is the “second-layer sub-electrode coil portion”, and the sub-electrode coil portion 92c is the “third-layer sub-electrode”. “Coil part”.

The auxiliary spare coil portions constituting the auxiliary electrode coil portions 92a, 92b, 92c are wound after the main auxiliary coil portions constituting the corresponding main electrode coil portions 19a, 19b, 19c are formed.
That is, the auxiliary secondary coil portion constituting the first-layer auxiliary electrode coil portion 92a is wound after the main auxiliary coil portion constituting the first-layer main electrode coil portion 19a is wound. The auxiliary spare coil part that constitutes the electrode coil part 92b is a secondary spare part that constitutes the auxiliary electrode coil part 92c of the third layer after the main auxiliary coil part of the main electrode coil part 19b of the second layer is wound. The coil portion is wound after the main preliminary coil portion constituting the third-layer main electrode coil portion 19c is wound.

Each metal wire forming the auxiliary spare coil portion (sub electrode coil portions 92a, 92b, 92c) of each layer forms a corresponding main electrode coil portion (main electrode coil portions 19a, 19b, 19c) of each layer. It is wound on each main spare coil portion so as to straddle a metal wire which is adjacent to the longitudinal direction of the electrode shaft 15.
As shown in FIG. 7, the metal wire used for the first-layer sub-electrode coil section 92a (sub-preliminary coil section) is connected to the first-layer main electrode coil section 19a (main-preliminary coil section) and the second layer. The size (diameter) of the second electrode sub-electrode coil portion 92b (sub-preliminary coil portion) is the same as that of the main electrode coil portion 19b (main auxiliary coil portion). As shown in FIG. 7, the metal wire used for the wire is between the second layer main electrode coil portion 19 b (main spare coil portion) and the third layer main electrode coil portion 19 c (main spare coil portion). It is a size (diameter) that fits within the gap.

Further, as shown in FIG. 7, the metal wire used for the third-layer sub-electrode coil portion 92c (sub-preliminary coil portion) is the outer periphery of the third-layer sub-electrode coil portion 92c (sub-preliminary coil portion). The one whose diameter is smaller than the outer peripheral diameter of the third layer main electrode coil portion 19c (main spare coil portion) is used.
The electrode 90 in the second embodiment also has a conical tip, and the angle between the generatrix and the axis is 30 degrees or less, so that the light extraction efficiency is improved as in the first embodiment. Can be increased.

  Further, the sub electrode coil portions 92a, 92b, and 92c are wound between the main electrode coil portions (first and second layers, second and third layers), and on the main electrode coil portion 19c located in the outermost layer. Since it is rotated, the surface area of the auxiliary electrode coil portions 92a, 92b, and 92c increases without increasing the size of the electrode itself, and as a result, the surface area of the electrode winding portion 91 can be increased. Thereby, the heat dissipation effect from the electrode can be enhanced when the lamp is lit.

  In the conventional electrode, the surface area of the electrode winding part necessary for heat dissipation is set. However, as described above, the surface area of the electrode winding part 91 is provided by providing the auxiliary electrode coil parts 92a, 92b, and 92c. Can be increased, the surface area of the main electrode coil portions 19a, 19b, 19c can be reduced by the increase in the surface area of the sub electrode coil portions 92a, 92b, 92c. Can be achieved.

In addition, since the secondary electrode (preliminary body) coil portion is composed of a metal wire that is thinner than the metal wire constituting the main electrode (preliminary body) coil portion, for example, variations in the main electrode (preliminary body) coil portion (for example, pitch) Disturbance of the pitch, opening of the pitch due to the spring back, etc.) can be compensated, and the overall shape of the electrode tip can be stabilized.
Although the present invention has been described based on each embodiment, the content of the present invention is not limited to the specific examples shown in the above embodiments. For example, the following modifications are possible. Can be further implemented.

1. Regarding the electrode preliminary body (1) Number of layers of the coil portion In each embodiment, the number of layers of the preliminary coil portion at the tip of the electrode preliminary body has been described as three layers. However, the number of layers of the preliminary coil portion according to the present invention Is preferably a natural number of 3 or more. This is because if the number of layers of the preliminary coil portion is two, even if the tip portion of the electrode preliminary body is formed in a tapered shape to constitute the electrode, it is tapered only in a narrow region of the tip portion. This is because the heat capacity necessary for the electrode itself when the lamp is lit may not be secured.

(2) Diameter of metal wire In each embodiment, although the diameter of the metal wire which comprises an electrode (and preliminary body) coil part was constant, for example, it uses by the electrode (and preliminary body) coil part of each layer The diameter of the metal wire may be different.
FIG. 8 is a longitudinal sectional view of an electrode preliminary body in which a preliminary coil portion is formed using metal wires having different diameters.

  As shown in FIG. 8, the electrode preliminary body 100 includes a shaft rod 102 to be an electrode shaft and a preliminary body winding portion 104 to be an electrode winding portion. The preliminary winding part 104 is composed of four layers of preliminary coil portions 106, 108, 110, 112, and is provided on the tip end 102a side of the shaft 102, and the preliminary coil portions 106, 108, 110, 112 of each layer. The diameters of the metal wires 106a, 108a, 110a, and 112a constituting each of these are different.

In the example of FIG. 8, the diameters of the metal wires 106 a, 108 a, and 110 a become smaller in the order of the first layer preliminary coil unit 106, the second layer preliminary coil unit 108, and the third layer preliminary coil unit 110. The fourth layer metal wire 112a has the same diameter as the second layer metal wire 108a.
As described above, the diameters of the metal wires constituting the preliminary coil portions 106, 108, 110, and 112 of each layer increase toward the upper layer, that is, the preliminary coil portions 106, 108, 110, and 112 are connected to the shaft rod (102). As you move away from), it may be smaller or vice versa. Furthermore, you may comprise a preliminary | backup body winding part by overlapping a preliminary | backup body coil part irrespective of the magnitude of the diameter of a metal wire.

Needless to say, in order to taper the electrode, it is better to reduce the diameter of the metal wire toward the upper layer.
However, if the preliminary coil portion is configured using arbitrarily different metal wire diameters, the metal wire for forming the coil portion may not be wound at the same pitch in the preliminary coil portion of each layer. Although it may occur, in the present invention, the pitch of the preliminary coil portion is not limited to a fixed one, and does not depart from the present invention.

  In this example, as in the embodiment, the spare coil portion of the k-th layer (k is 2, 3 and 4) is also positioned at the tip of the shaft rod 102 in the spare coil portion (for example, 108b, 110b, and 112b), from the position of the tip of the shaft rod 102 in the lower preliminary coil portion to at least one metal wire of the lower preliminary coil portion to the rear end of the shaft rod 102, FIG. Then, 1.5 are separated.

(3) Termination Shape of Coil Part Although the number of turns of each electrode (and spare body) coil part in each embodiment has not been specifically described, the number of turns of each electrode (and spare body) coil part is different from that of other electrodes. (And spare body) It may be the same as the number of turns of the coil part, or may be different.
In the embodiment, the end of the electrode coil portion opposite to the tip side (this end portion is referred to as a “termination portion”) remains in a wound state. The terminal portion may be melt processed and integrated with the shaft rod.

FIG. 9 is a diagram showing an outline of an electrode in which a terminal portion of a coil portion is welded.
As shown in FIG. 9, the end portion 122 of the electrode 120 is tapered, while the terminal portion 124 of the winding portion is melted over the entire circumference and is integrally fixed to the shaft rod 126. ing. The shape of the terminal portion 124 is flat here, but is not particularly limited as long as the metal wire can be melted and fixed to the shaft rod 126.

As described above, when the terminal end portion of the preliminary body winding portion is melted and integrated with the shaft rod, the opening of the pitch of each electrode coil portion due to the thermal expansion of the metal wire during lighting can be suppressed. Note that if the pitch of the electrode coil portion is increased during lighting, the lamp comes into contact with the discharge vessel (quartz glass) or the temperature of the sealing portion changes, leading to a shortened life of the lamp.
In addition, when the terminal part of a preliminary | backup body winding part is fuse | melted and integrated with a shaft rod, it is necessary to give a some margin in each preliminary | backup body coil part.

(4) About formation of electrode preliminary body In each embodiment (for example, (a) of Drawing 2), an electrode preliminary body makes a preliminary body coil part by winding a metal wire directly around a shaft rod, and this is done. By repeating a plurality of times (for a plurality of layers), a preliminary winding part composed of a multilayer preliminary coil part is formed. However, the (preliminary body) coil portion of the electrode preliminary body of the present invention is not limited to one configured by winding a metal wire directly around a shaft rod.

  For example, a coil corresponding to the preliminary coil portion of each layer is formed in advance, and the formed coil (corresponding to the coil portion of the first layer) is fitted to the shaft rod. A coil (corresponding to the coil portion of the second layer) to be positioned on the upper layer of the coil that is fitted is attached (so that the coil moves on the lower layer coil to the other end side of the shaft rod). It is also possible to form a spare body winding portion composed of a plurality of layers of the preliminary body coil portion by fitting while rotating.

(5) Others In each embodiment, the pitch of the metal wire in the preliminary body (electrode) coil portion is the same in each layer, but the preliminary body (electrode) coil portion in each layer may be formed in a coil shape having a different pitch. Further, the spare body (electrode) coil portion of each layer is not a constant pitch, only the portion corresponding to the tip of the shaft rod is a constant pitch, and the other portions are different from the constant pitch. Also good.

Moreover, in each embodiment, although the material of the metal wire which comprises the preliminary | backup body (electrode) coil part (including main and sub) of each layer was made the same, the coil part which concerns on this invention is used by each layer. The material of the metal wire may be different.
Furthermore, in the electrode preliminary body in 1st Embodiment, the number of the metal wires and the number of layers of the preliminary body coil part were made the same. In other words, the three-layer preliminary coil portion was formed using three metal wires (one coil portion was formed with one metal wire to make a total of three-layer coil portions). You may form the preliminary | backup coil part of all the layers using one metal wire. In this case, after forming one preliminary body coil part, it can implement by reversing and winding a metal wire in the reverse direction.

2. Regarding the electrode (1) Shape In the embodiment, only the top of the tip has a hemispherical shape, and the other part has a frustoconical shape (having a circular water surface). The electrode may have another tapered shape. Another shape may be a frustoconical shape having no tip in the embodiment.

  Furthermore, it may be a polygonal pyramid shape such as a hexagonal pyramid shape instead of a conical shape. In this case, the apex of the tip may be hemispherical (in many cases, hemispherical for processing) or may not be present (a truncated polygonal cone). Such a shape can be implemented, for example, by using a shaft having a polygonal cross-sectional shape, and forming the preliminary coil portion with a metal wire that can be deformed along its outer peripheral surface.

FIG. 10 is a longitudinal sectional view of electrodes having different shapes.
As shown in FIG. 10, in the electrode 130, the dimension of the electrode shaft 138 in the longitudinal direction of the third-layer electrode coil portion 136 among the plurality of electrode coil portions 132, 134, 136 is longer than the melting portion 140 of the electrode 130. For example, the number of turns of the metal wire may be one or more times (one time here) with respect to the portion to be melted, or may be incorporated as another electrode structure having a different structure. good.

(2) Electrode In the electrode of the embodiment, the end opposite to the electrode coil portion of the electrode shaft was fixed to the metal foil and sealed to the sealing portion as an electrode structure. The electrode may be sealed to the sealing portion with another structure.

  The present invention can be used to easily and inexpensively manufacture an electrode having a tapered tip.

It is a figure which shows the structure of the high pressure mercury lamp which concerns on 1st Embodiment. It is an enlarged view of an electrode, (a) is an external view of an electrode, (b) is a longitudinal cross-sectional view of an electrode. It is a figure which shows the structure of a lamp unit, and cuts off a part of reflecting mirror so that the mode of an internal lamp | ramp may be understood. It is a figure explaining the manufacturing process of an electrode. (A) is a figure which shows an electrode preliminary body, (b) is a longitudinal cross-sectional view of an electrode preliminary body. It is a figure which shows the outline of a melt process. It is an enlarged view of the partial cross section of the electrode which concerns on 2nd Embodiment. It is a longitudinal cross-sectional view of the electrode preliminary body which formed the coil part using the metal wire of a different diameter. It is a figure which shows the outline of the electrode which welded the terminal part of the coil part. It is a longitudinal cross-sectional view of the electrode from which a shape differs. It is an enlarged view of a pair of electrode which opposes in the conventional short arc type high pressure discharge lamp. It is an enlarged view of a pair of electrodes which face in a conventional short arc type high pressure discharge lamp.

Explanation of symbols

1 Lamp 7, 9 Electrode 15, 17 Electrode shaft 19, 21 Electrode coil 50 Shaft bar 50a Tip 52 Electrode reserve 56 Winding 56a, 56b, 56c Coil

Claims (8)

A method for producing an electrode for a high-pressure discharge lamp, comprising:
A forming step of forming an electrode preliminary body by stacking n layers (n is a natural number of 2 or more) of a coil portion formed by winding a metal wire in a coil shape on the tip portion of the shaft rod;
A melting step of heating and melting the tip of the electrode preliminary body in a tapered shape,
In the forming step, the coil portion of the n-layer is arranged such that the end position on the tip side of the coil portion of the k-th layer (k is a natural number of n or less and a natural number of 2 or more) is the coil portion of the (k-1) -th layer. The electrode is characterized in that it is stacked in a state where it is separated from the end position of the tip end side of the shaft rod by one metal wire constituting the coil portion of the k-1 layer from the rear end side in the extending direction of the shaft rod. Production method. In the forming step,
After stacking the n-th coil portion which is the outermost layer,
A second coil portion formed by winding a second metal wire across a metal wire adjacent to the longitudinal direction of the shaft rod, which is a metal wire constituting the coil portion,
2. The method for manufacturing an electrode according to claim 1, wherein an outer peripheral diameter of the second coil portion is equal to or smaller than an outer peripheral diameter of the n-th coil portion. In the forming step,
Before stacking the k-th coil,
a third coil portion, which is a metal wire constituting the coil portion of the (k-1) th layer and wound around a metal wire adjacent to the longitudinal direction of the shaft rod, is overlaid;
The metal wire of the third coil portion is sized to fit in a gap between the metal wire constituting the coil portion of the k-1th layer and the metal wire constituting the coil portion of the kth layer. The manufacturing method of the electrode of Claim 1 or 2. After the forming step,
The fixing process which heat-melts the rear-end part on the opposite side to the said front-end | tip in each coil part, and fixes each coil part to the said axis | shaft rod is performed. The manufacturing method of the electrode of description. An electrode manufacturing process for manufacturing an electrode, and a high pressure discharge lamp manufacturing method including a sealing process for sealing the electrode manufactured in the process to a discharge vessel,
In the said electrode manufacturing process, the manufacturing method of the electrode of any one of Claims 1-4 is performed. The manufacturing method of the high pressure discharge lamp characterized by the above-mentioned. A coil portion formed by winding a metal wire in a coil shape is stacked on the tip portion of the shaft rod, and n tips (n is a natural number of 2 or more) are stacked, and the tips of the coil portions stacked in the n layers are heated and melted. An electrode for a high-pressure discharge lamp in which the entire tip of the coil portion that is layered has a conical shape,
The conical shape has an angle between an axis of the cone and a generatrix of 30 degrees or less. A metal wire that constitutes the n-th layer coil portion and includes a second coil portion that is formed by winding a second metal wire across a metal wire adjacent to the extending direction of the shaft rod;
The electrode for a high-pressure discharge lamp according to claim 6, wherein an outer peripheral diameter of the second coil portion is equal to or smaller than an outer peripheral diameter of the n-th coil portion. A metal wire constituting a coil portion of the k-1th layer (k is a natural number of n or less and a natural number of 2 or more) and extends over the metal wire adjacent to the longitudinal direction of the shaft rod, the third metal A third coil portion formed by winding a wire;
The metal wire of the third coil portion is sized to fit in a gap between the metal wire constituting the coil portion of the k-1th layer and the metal wire constituting the coil portion of the kth layer. The electrode for high pressure discharge lamps according to claim 6 or 7.

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