JP2009048868A - Discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp with intensity at a welding part enhanced of an electrode formed by welding a base part and a lid part, and capable of filling gas without any trouble in a closed space of the electrode. <P>SOLUTION: In the discharge lamp in which one of the pair of electrodes arranged in opposition in an arc tube in a tube axis direction is so structured to have a heat transfer body made of metal with a lower melting point than that constituting a metal base part of a bottomed cylinder shape having an opening at a base end side sealed in a closed space formed by the metal base part and a metal lid part fitted into an inner space of the base body, the electrode is provided with a gas guide-in flow channel extended from the base end part of the lid part toward the closed space along a center axis of the electrode, and a heat transfer body capturing space communicated with the gas guide-in flow channel and extended along the center axis of the electrode. The heat transfer body capturing space has a larger width in a direction crossing the center axis of the electrode than the gas guide-in flow channel. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a discharge lamp. In particular, the present invention relates to a short arc type discharge lamp used as a light source for a projection exposure apparatus, a photochemical reaction apparatus or the like.

  Conventionally, various discharge lamps are known. Among high-pressure mercury lamps in which mercury is sealed in an arc tube, particularly a short arc type high-pressure mercury lamp has an i-line with a wavelength of 365 nm or a wavelength of 436 nm. Since it has a light emission characteristic of emitting g-line, it is used as a light source for an exposure apparatus for exposing, for example, a semiconductor wafer, a liquid crystal substrate, and the like. In such a short arc type discharge lamp, there is a strong demand for high output so that the exposure process can be executed with high processing efficiency.

In order to increase the output of the high-pressure mercury lamp, normally, the rated power is increased, but in this case, the rated current is usually increased. Therefore, in particular, the anode of a high-pressure mercury lamp that is lit by direct current has a problem that the amount of electrons that collide with the anode becomes high and melts.
In addition, in a high-pressure mercury lamp that is lit in a posture in which a pair of electrodes are opposed to each other in the vertical direction, the electrode located in the vertical direction may be affected by the heat of the arc due to the influence of thermal convection in the arc tube. It may melt at high temperatures.

  When the tip portion of the electrode is melted, not only the arc becomes unstable, but also the amount of light emitted from the high-pressure mercury lamp is reduced by adhering the evaporated material to the inner wall of the arc tube. The problem of being reduced arises.

  In order to solve the above problems, a heat transfer body made of a metal having a melting point lower than that of the metal constituting the electrode is sealed in a sealed space formed inside, and a predetermined gas pressure is obtained. There has been proposed a discharge lamp including an electrode having a configuration in which a buffer gas is sealed (see Patent Documents 1 and 2). This will be described below with reference to FIGS. 1, 2 and 13.

  As shown in FIG. 1, this discharge lamp includes an arc tube 10 including a substantially spherical arc tube portion 11 and rod-shaped sealing portions 12 formed continuously at both ends of the arc tube portion 11. Yes. In the arc tube portion 11, a pair of electrodes each consisting of an anode 14 and a cathode 16 made of tungsten are arranged opposite to each other.

As shown in FIG. 13, the anode 14 is formed at the base end portion of the base portion 20 in a state where the columnar insertion portion 42 of the lid portion 40 is inserted into the internal space of the bottomed cylindrical base portion 20. The flat surfaces in contact with each other in the formed base portion side flange portion 24 and the lid portion side flange portion 44 formed at the front end portion of the cover portion 40 are welded over the entire circumferential direction so as to be sealed inside. The space C is formed. In the sealed space C, a heat transfer body M made of a metal having a melting point lower than that of tungsten constituting the anode 14 is enclosed.
As shown in FIG. 2, the lid 40 has an arcuate projecting portion 47 having an arc-shaped projecting portion 47 provided with notches at two locations in the circumferential direction on the end surface on the proximal end side, and a convex in an isolated state in the circumferential direction. As shown in FIG. 13, it has a gas introduction flow path 51 that extends along the central axis of the anode 14 and that passes through the lid 40 and communicates with the sealed space C. Yes.

  According to the discharge lamp including the anode 14 having the above-described configuration, when the discharge lamp is turned on, the heat transfer body M that is in a liquid state by being melted convects in the sealed space C, so that the anode 14 The heat accumulated in the vicinity of the distal end located on the lower side in the vertical direction is transported toward the base end of the anode 14 with high efficiency, so that the distal end 14A of the anode 14 becomes overheated. Is prevented.

In addition, according to the above-described discharge lamp, when the amount of the heat transfer body M enclosed in the sealed space C is large, the buffer in the sealed space C of the anode 14 is, for example, a gas pressure of 1 atm or more. By enclosing the gas, it is possible to prevent bubbles from being generated between the heat transfer body M and the inner wall surface of the sealed space C, and there is no possibility that the efficiency of the heat transport is reduced due to the bubbles.
On the other hand, according to the above discharge lamp, when the amount of the heat transfer body M enclosed in the sealed space C is small, the inside of the sealed space C of the anode 14 has a gas pressure of, for example, 1 atm or less. By enclosing the buffer gas, the boiling of the heat transfer body M is promoted, and thereby the efficiency of heat transport by the boiling transmission can be increased.
That is, according to the above-described discharge lamp, the efficiency of heat transport by the heat transfer body M is increased by optimally adjusting the gas pressure in the sealed space C according to the amount of the heat transfer body M enclosed. Can do.

JP 2004-6246 A JP 2006-179461 A

However, according to the above-described discharge lamp, when the anode 14 is manufactured, the heat transfer body M leaks to the outside of the lid portion 40 through the gas introduction flow path, and the base portion 20 and the lid portion 40 When mixed in the welded portion, there may be a problem that the welding strength of the welded portion W in the anode 14 is lowered.
Further, according to the above discharge lamp, the gas introduction flow path is blocked by the heat transfer body M, so that the buffer gas is sealed in the sealed space C that is executed after the step of forming the welded portion W. In the process, there was a problem that the introduction of the buffer gas was hindered.

  The reason why such a problem occurs is not clear, but is considered as follows. The process of welding the base 20 and the lid 40 includes filling the opening M of the bottomed cylindrical base 20 with the heat transfer body M and the cylindrical fitting portion 42 of the lid 40 at the opening of the base 20. It is executed after insertion. When the base portion side flange portion 24 and the lid portion side flange portion 44 of the base portion 20 are welded in the circumferential direction, the heat transfer body M becomes considerably hot and melts, and is in a liquid state. When the bubbles contained in the heat transfer body M rise and bounce off the surface, the scattered heat transfer body splash may adhere to the vicinity of the opening 51 </ b> A on the distal end side in the gas introduction channel 51. In this case, the heat transfer body splash adhering to the vicinity of the opening 51A of the gas introduction channel 51 flows out of the lid part 40 through the gas introduction channel by capillary action and flows into the welded portion. The gas introduction flow path 51 is blocked by solidifying after the end of the welding process in a state where the gas introduction flow path 51 is located in the middle of the gas introduction flow path 51 even if it is mixed or does not flow out of the lid portion 40. It is expected to end up.

  The present invention was made in order to eliminate the occurrence of the above-described problems, and has a high strength in the welded portion of the electrode formed by welding the base portion and the lid portion, An object of the present invention is to provide a discharge lamp capable of filling a gas in a sealed space of an electrode without any trouble and having a desired heat transport efficiency.

The discharge lamp of the present invention is a bottomed cylindrical metal base portion in which one of a pair of electrodes arranged in the arc tube so as to face each other in the tube axis direction of the arc tube has an opening on the base end side; A structure in which a heat transfer body made of a metal having a melting point lower than that of the metal constituting the base portion is enclosed in a sealed space formed by a metal lid portion fitted into the internal space of the base portion. In having
The electrode extends along the central axis of the electrode from the base end portion of the lid portion toward the sealed space, and communicates with the gas introduction flow channel and along the central axis of the electrode. And a heat transfer body capture space that extends
The heat transfer body capturing space is characterized in that the width in the direction orthogonal to the central axis of the electrode is larger than that of the gas introduction channel.

  In the discharge lamp of the present invention, the lid portion is formed with a groove portion that is recessed toward the central axis direction of the electrode, and the heat transfer body capturing space is formed by the groove portion and the inner wall surface of the base portion. It is characterized by being partitioned.

  In the discharge lamp of the present invention, the base portion is formed with a groove portion that is recessed toward the outer peripheral surface in the radial direction of the base portion at a location facing the cover portion, and the groove portion and the lid portion The heat transfer body capturing space is partitioned by an outer peripheral surface of the heat transfer body.

In the discharge lamp of the present invention, the melting point is higher than that of the metal constituting the base portion in the sealed space formed by the metal base portion and the metal lid portion inserted into the internal space of the base portion. A heat transfer body made of a low metal is enclosed.
In addition, the electrode according to the discharge lamp of the present invention includes a gas introduction channel extending from the base end portion of the lid portion toward the sealed space, and a heat transfer body capturing space formed wider than the gas introduction channel. Therefore, in the step of forming the welded portion by welding the base portion and the lid portion, it is scattered toward the gas introduction flow path and travels along the gas introduction flow path in the proximal direction of the electrode. Since the splash of the heat transfer body that is about to flow out of the heat transfer body stays in the heat transfer body capturing space and is prevented from flowing out in the proximal direction from the heat transfer body capturing space, it flows out of the lid portion. There is no fear, and there is no possibility of closing the gas introduction flow channel located in the proximal direction from the heat transfer body capturing space. Therefore, the strength of the welded portion between the base portion and the lid portion can be increased, and there is no possibility that filling the gas in the sealed space of the electrode is hindered. As a result, convection of the molten heat transfer body occurs during lighting, and the temperature of the entire electrode can be made uniform by utilizing the convection action of the heat transfer body, so that the tip of the electrode becomes excessively hot. This can be prevented.

  Furthermore, in the discharge lamp according to the present invention, since the groove portion recessed in the direction of the central axis of the electrode is formed in the lid portion, the heat transfer body is formed by the groove portion and the inner wall surface of the base portion. The capture space can be reliably partitioned.

  Further, in the discharge lamp of the present invention, the groove portion that is depressed toward the outer peripheral surface in the radial direction of the base portion is formed at a location facing the lid portion in the base portion. With the outer peripheral surface of the part, the heat transfer body capturing space can be reliably partitioned.

FIG. 1 is a cross-sectional view showing an example of the configuration of the discharge lamp of the present invention.
The arc tube 10 is made of quartz glass, and rod-shaped sealing portions 12 are integrally and continuously formed at both ends of a substantially spherical arc tube portion 11. A pair of electrodes each made of a metal anode 14 and cathode 16 are arranged in the arc tube portion 11 so as to face each other. An electrode core rod 17 extending from each of the anode 14 and the cathode 16 is held in the sealing portion 12 and is connected to an external lead rod or metal via a metal foil (not shown) provided in an airtight manner in the sealing portion 12. It is connected to an external terminal, and an external power source is connected to this.
A predetermined amount of a luminescent material such as mercury, xenon, or argon or a starting gas is sealed in the arc tube 11.

  Such a discharge lamp emits light by arc discharge between the anode 14 and the cathode 16 when electric power is supplied from an external power source. In the discharge lamp shown in the example of FIG. 1, the anode 14 is arranged in a vertically upper side and the cathode 16 is arranged in a vertically lower side, that is, the tube axis of the arc tube unit 11 is perpendicular to the ground. It is a vertical lighting type that is supported and lit.

FIG. 2 is a perspective view showing the appearance of the anode 14. FIG. 3 is an enlarged cross-sectional view of the anode 14. FIG. 4 shows an enlarged cross section of the main part of the anode of the discharge lamp of FIG. 1 and shows the cross section viewed from the AA ′ direction.
The anode 14 is shown in a state in which a tip portion 14A facing the cathode 16 is positioned downward in the vertical direction. The anode 14 is configured such that a heat transfer body M is enclosed in a sealed space C formed by fitting and welding the base portion 20 and the lid portion 40.

The base portion 20 has a bottomed cylindrical shape in which an inner space 22 having an opening 21 is formed on an end face of a base end portion (an end portion opposite to the tip end portion 14A of the anode 14), and the base end portion has a radial direction at the base end portion. A base portion side flange portion 24 protruding outward is formed. The base portion side flange portion 24 is continuous with the base portion side flat surface 23 extending in the radial direction and the outer peripheral edge of the base portion side flat surface 23, and the base portion side inclined surface extending radially inward toward the distal end direction. 26.
The base portion side flange portion 24 is formed with an annular groove 25 extending in the circumferential direction at a position close to the base end portion of the base portion 20, and the annular groove 25 is formed by the base end portion side inclined surface 26. Yes. The outer diameter of the base portion side flange portion 24 is smaller than the outer diameter of the base portion 20. As a result, even after the base portion 20 and the lid portion 40 are welded, a portion having a diameter larger than the outer diameter of the base portion 20 is not formed, and the outer diameter of the base portion 20 is increased when the discharge lamp is assembled. However, it is not necessary to use a glass tube having a large inner diameter. Therefore, there is an advantage that a conventional envelope can be used without requiring a design change.

  The lid portion 40 includes a lid body 41 having a truncated cone shape as a whole, and a cylindrical fitting portion 42 that is integrally formed so as to protrude from the center of the bottom surface of the lid body 41. The lid main body 41 has a lid portion side flange portion 44 having the same outer diameter as the base portion side flange portion 24. The lid-side flange portion 44 is continuous with the lid-side flat surface 43 extending radially outward and the outer peripheral edge of the lid-side flat surface 43, and is a circle extending radially inward toward the proximal direction. It has a truncated cone shape having an annular lid-side slope 46. The fitting portion 42 is formed so as to protrude from the lid portion-side flat surface 43 in the distal direction, and has an outer diameter that matches the inner diameter of the inner space 22 of the base portion 20.

  The lid portion 40 has an arcuate protrusion 47 formed by punching a central portion of the base end side end surface at the base end portion thereof, and is depressed from the base end surface of the arc-like protrusion portion 47 toward the tip end of the anode 14. Two recesses 47A and 47B that are recessed toward the distal end direction of the anode 14 in succession to one end side and the other end side of the arc-shaped projecting portion 47, and the recess 47A, A connecting hole 49 is formed in the center of the bottom surface 48A of the recess 48 to which the electrode core rod 17 is press-fitted. .

  Further, the lid portion 40 is formed in an annular groove portion 50 formed on the outer peripheral surface of the base end portion 42B of the insertion portion 42 and extending over the entire circumferential direction of the insertion portion 42, and a convex portion 47C of the lid portion 40. In addition, it has a gas introduction flow channel 51 that extends in the distal direction along the central axis of the anode 14 (hereinafter, also simply referred to as “central axis”) and communicates with the groove 50. An opening 51 </ b> A that leads to the sealed space C is formed in the distal end surface of the fitting portion 42 when the gas introduction flow channel 51 penetrates the lid portion 40 in the central axis direction. The groove 50 is formed to have a larger width in the direction orthogonal to the central axis of the anode 14 (hereinafter also simply referred to as “width”) than the gas introduction flow path 51.

  Then, the fitting portion 42 of the lid portion 40 is fitted into the internal space 22 of the base portion 20, and the lid portion side flat surface 43 of the lid portion side flange portion 44 is formed on the base portion side flat surface 23 of the base portion side flange portion 24. The outer peripheral edge portion of the base portion side flange portion 24 and the outer peripheral edge portion of the lid portion side flange portion 44 which are brought into contact with each other and overlapped in this state are welded to form an annular welded portion W.

In such an anode 14, the fitting portion 42 of the lid portion 40 is fitted into the internal space 22 of the base portion 20, whereby the inner peripheral surface 21 </ b> A of the opening 21 of the base portion 20 and the groove portion 50 of the fitting portion 42. A heat transfer body capturing space S is defined. The heat transfer body capturing space S has a width wider than the gas introduction channel 51. Here, as shown in FIG. 4, the width of the heat transfer body capturing space S is the same as that of the inner peripheral surface 21A of the opening 21 in a cross section obtained by cutting the anode 14 along a plane including the central axis and the gas introduction flow path 51. The shortest distance X between the wall surface 50X of the groove part 50 facing the inner peripheral surface 21A is meant. The width of the gas introduction channel 51 means a width Y in a direction perpendicular to the central axis of the anode 14 as shown in FIG.
Specifically, the heat transfer body capturing space S has a width X of 0.6 to 3 mm and a total length in the central axis direction of 1 to 5 mm, and the gas introduction channel 51 has a width of 0.3 to 1 mm and a center. The total length in the axial direction is 20 to 25 mm. The width X of the heat transfer body capturing space S is preferably in the range of X> 2Y with respect to the width Y of the gas introduction channel 51.

Each of the anode 14 and the cathode 16 is made of a metal having a high melting point, and specifically, is made of a metal having a melting point of about 3000 ° C. or higher, such as tungsten, rhenium, or tantalum. Among these, tungsten is particularly preferable.
On the other hand, the heat transfer body M is made of a metal having a low melting point at the time of lighting as compared with the metal constituting the electrode. Specifically, when the electrode is made of tungsten, silver, copper, gold, indium , Tin, zinc, lead and the like are used.

  In the anode 14 using such a metal as the heat transfer body M, when the discharge lamp is turned on, the heat transfer body M melts and convection is generated inside the sealed space C of the anode 14, so that the tip of the anode 14 Since the heat of 14A is transported in the proximal direction of the anode 14, the heat accumulated in the vicinity of the distal end portion 14A of the anode 14 is efficiently transported, so that the distal end portion 14A of the anode 14 is melted. Can be avoided. In addition, a large current can be passed through the discharge lamp, and the output of the discharge lamp can be increased.

  A rare gas is sealed in the sealed space C so as to have a predetermined pressure. Specifically, when 50% or more of the heat transfer body M is sealed with respect to the internal volume of the sealed space C, the rare gas is sealed at 1 atm or more, whereby the heat transfer body M and the sealed space C are sealed. Bubbles are prevented from being generated at the interface with the inner surface. On the other hand, when the amount of the heat transfer body M enclosed with respect to the internal volume of the sealed space C is small, the boiling of the heat transfer body M is promoted by setting the inside of the sealed space C to a pressure state lower than the atmospheric pressure. The heat transport effect due to boiling transfer can be expected.

The anode 14 is produced as follows.
First, the base portion 20 and the lid portion 40 having the above-described configuration are manufactured by cutting a cylindrical member made of tungsten.
Second, the inner space 22 of the base portion 20 is filled with the heat transfer body M, and the fitting portion 42 of the lid portion 40 is fitted into the inner space 22 through the opening 21 of the base portion 20 so that the base portion side is flat. The welded portion W is formed by welding the outer peripheral edge portions of the base portion side flange portion 24 and the lid portion side flange portion 44 adjacent to each other on the surface 23 with the lid portion side flat surface 43 being in contact with each other. Form.
Third, after the rare gas is sealed in the sealed space C via the gas introduction flow path 51 and the heat transfer body capturing space S formed in the lid portion 40, the convex portion 47C formed in the lid portion 40 is formed. The gas introduction flow path 51 is sealed by melting the gas.

  According to the discharge lamp of the present invention as described above, the base portion 20 and the metal lid portion 40 having the columnar insertion portion 42 to be inserted into the internal space 22 of the base portion 20 are fitted. Since the heat transfer body M made of a metal having a melting point lower than that of the metal constituting the base portion 20 is enclosed in the sealed space C formed by the above, basically the heat transfer body M melted at the time of lighting. Is generated, and the temperature of the anode 14 as a whole can be made uniform by utilizing the convection action of the heat transfer body M. Therefore, it is possible to prevent the tip 14A of the anode 14 from becoming excessively hot. it can.

  Moreover, since the anode 14 has a gas introduction channel 51 and a heat transfer body capturing space S formed wider than the gas introduction channel 51, the base portion 20 and the lid portion 40 are welded together. Thus, in the process of forming the welded portion W, the light is scattered toward the opening 51A of the gas introduction flow channel 51 and is transmitted through the gas introduction flow channel 51 toward the proximal end of the anode 14. The droplets of the heat body M are prevented from flowing out in the proximal direction from the heat transfer body capturing space S by staying in the heat transfer body capturing space S. Thereby, there is no possibility that the droplets of the heat transfer body M flow out of the lid 40 through the gas introduction flow path 51, and the gas introduction located in the proximal direction from the heat transfer body capturing space S is performed. Since there is no possibility of closing the flow path 51, the strength of the welded portion W between the base portion 20 and the lid portion 40 can be increased, and the gas can be filled into the sealed space C of the anode 14. There is no risk of obstruction.

  Furthermore, the base portion 20 of the anode 14 has an inner diameter of the opening 21 that does not completely match the outer diameter of the fitting portion 42, but is 0.5 to 1.5% of the outer diameter of the fitting portion 42. It is formed to a large extent. Therefore, when welding the base | substrate part 20 and the cover part 40, the droplet of the heat transfer body M stays in the flow path 51B for gas introduction located in the front end direction rather than the heat transfer body capture | acquisition space S, and complete | finishes a welding process. Even if the gas introduction flow path 51B is closed by the splash of the heat transfer body that is naturally cooled and solidified later, the gap between the inner peripheral surface 21A of the opening 21 of the base portion 20 and the outer peripheral surface 42A of the fitting portion 42 is between. Gas can be filled into the sealed space C through the existing annular gap T.

  While a specific example of the present invention has been described above, various modifications can be made in the present invention. 5 to 12 are sectional views showing other embodiments of the anode of the present invention. Parts common to the anodes shown in FIGS. 2 to 4 in the anode shown in FIGS.

  In the anode 14 shown in FIG. 5, an annular groove portion 50 is formed over the entire length in the circumferential direction of the insertion portion 42 closer to the distal direction than the base end portion 42 </ b> B of the insertion portion 42. The end surface 50 </ b> A is formed closer to the tip direction than the base portion side flat surface 23 of the base portion 20. According to the configuration shown in the figure, the heat transfer body capturing space S is formed from the peripheral portions of the base part side flange part 24 and the cover part side flange part 44 that are heated when the base part 20 and the cover part 40 are welded. Since it is far away, the droplets of the heat transfer body M accumulated in the heat transfer body capturing space S during welding are less likely to evaporate, so that the splashes of the heat transfer body M travels along the gas introduction channel 51 to the outside of the lid 40. There is no fear of flowing out, and the amount of the heat transfer body M can be maintained at the desired amount. The configuration shown in the figure is particularly effective when a large amount of heat transfer body M corresponding to, for example, 50 to 95% is enclosed with respect to the internal volume of the sealed space C.

  In the anode 14 shown in FIG. 6, annular grooves 50 are formed at two locations spaced in the center axis direction of the fitting portion 42, and each groove 50 communicates with the gas introduction flow channel 51. According to the configuration shown in the figure, the droplets of the heat transfer body M that is about to flow out in the proximal direction beyond the first heat transfer body capturing space S1 located on the distal end side are located on the proximal end side. It can be captured by the heat transfer body capturing space S2. Like the anode 14 shown in FIG. 5, the anode 14 shown in FIG. 5 is particularly effective when a large amount of heat transfer body M corresponding to, for example, 50 to 95% of the inner volume of the sealed space C is enclosed. It is. In addition, when the full length of the insertion part 42 is long, more groove parts 50 can be formed in two places.

In the anode 14 shown in FIG. 7, an annular groove 50 is formed in the entire circumferential direction over most of the outer peripheral surface 42 </ b> A of the fitting portion 42. Specifically, the groove part 50 has a total length of about 50 to 80% with respect to the total length of the fitting part 42 in the central axis direction. According to the configuration shown in the figure, the heat transfer body capturing space S is relatively larger in volume than the anode 14 shown in FIGS. 3 to 6, so that a large amount of heat transfer body droplets can be stored. Therefore, like the anode 14 shown in FIGS. 5 and 6, it is particularly effective when a large amount of heat transfer body M corresponding to, for example, 50 to 95% is enclosed with respect to the internal volume of the sealed space C.
In the anode 14 shown in FIGS. 5 to 7, the width of the heat transfer body capturing space S and the width of the gas introduction channel 51 have the same meanings as those of the anode 14 shown in FIGS. 3 and 4, respectively. Have

The anode 14 shown in FIG. 8 is different from the anode 14 shown in FIGS. 3 to 7 in that an arcuate groove 50 is formed on a part of the outer peripheral surface 42A of the fitting portion 42 in the circumferential direction. According to the anode 14 shown in the figure, substantially the same effect as that of the anode 14 shown in FIGS. 3 and 4 can be expected.
According to the anode 14 shown in FIG. 8, the width of the heat transfer body capturing space S is the same as that of the inner peripheral surface 21 </ b> A of the opening 21 in the cross section obtained by cutting the anode 14 along a plane including the central axis and the gas introduction channel 51. , Means the shortest distance X between the wall surface 50X of the groove portion 50 facing the inner peripheral surface 21A, and the width of the gas introduction flow path 51 is a direction perpendicular to the central axis of the anode 14 in the cross section. The width Y is meant.

The anode 14 shown in FIG. 9 is different from the anode 14 shown in FIGS. 3 to 8 in that the gas introduction flow path 51 formed in the lid portion 40 is inserted without penetrating the lid portion 40 in the central axis direction. It only communicates with the base end surface 50A of the annular groove 50 formed over the entire circumferential direction of the outer peripheral surface 42A of the portion 42. In the anode 14 shown in the figure, the gas introduction flow path 51, the heat transfer body capturing space S, and the inner peripheral surface 21A of the opening 21 of the base portion 20 and the outer peripheral surface 42A of the fitting portion 42 exist. The gas can be filled into the sealed space C through the annular gap T.
In the anode 14 shown in FIGS. 3 to 9, the heat transfer body capturing space S is partitioned by the inner peripheral surface 21 </ b> A of the opening 21 of the base portion 20 and the groove portion 50 of the fitting portion 42.

The anode 14 shown in FIG. 10 is different from the anode 14 shown in FIGS. 3 to 9 in the base portion 20, which is the inner peripheral surface of the opening 21, and the outer periphery of the fitting portion 42 of the lid portion 40 in the radial direction. An annular groove 50 is formed over the entire circumferential direction in a region facing the surface 42A. The lid portion side flange portion 44 penetrates the lid portion side flange portion 44 along the central axis so that an opening 51A is formed at the boundary portion between the lid portion side flat surface 43 and the outer peripheral surface 42A of the fitting portion 42. A gas introduction channel 51 extending in this manner is formed. The opening 21 of the base portion 20 has a width that does not hinder the flow of gas introduced from the opening 51A. Specifically, the width of the fitting portion 42 and the gas introduction flow path 51 are provided. And a width that is at least larger than the sum of the widths.
In the anode 14 shown in the figure, the heat transfer body capturing space S is partitioned by the groove portion 50 formed in the base portion 20 and the outer peripheral surface 42A of the fitting portion 42. Here, according to the anode 14 shown in the figure, the width of the heat transfer body capturing space S is the outer circumference of the fitting portion 42 in a cross section obtained by cutting the anode 14 along a plane including the central axis and the gas introduction channel 51. This means the shortest distance X between the surface 42A and the wall surface 50X of the groove 50 facing the outer peripheral surface 42A, and the width of the gas introduction channel 51 is a direction orthogonal to the central axis of the anode 14 in the cross section. Width Y.

In the anode 14 shown in FIGS. 11 and 12, the heat transfer body capturing space S is formed without forming a groove portion in any of the base portion 20 and the lid portion 40.
According to the anode 14 shown in FIG. 11, the lid 40 includes a truncated cone-shaped lid main body 41 and a columnar fitting portion integrally formed so as to protrude from the center of the bottom surface of the lid main body 41. 42. The fitting portion 42 includes a columnar base end side columnar portion 421 that is continuous with the lid portion main body portion 41, and a base end side columnar portion 421 that is continuously formed on the distal end side of the base end side columnar portion 421. Is also configured by a columnar tip side columnar portion 422 having a small outer diameter. The lid portion 40 passes through the lid body portion 41 and the base end side columnar portion 421 so as to form an opening 51A in the base end side columnar portion 421 and communicates with the internal space 22 of the base portion 20. An introduction channel 51 is provided.
In the anode 14 shown in the figure, an annular heat transfer body capturing space S is formed between the inner peripheral surface 21A of the opening 21 of the base portion 20 and the outer peripheral surface 422A of the tip side columnar portion 422. Here, according to the anode 14 shown in the figure, the width of the heat transfer body capturing space S is the tip side columnar portion 422A in a cross section obtained by cutting the anode 14 along a plane including the central axis and the gas introduction channel 51. Means the shortest distance X between the outer peripheral surface 422A and the inner peripheral surface 21A of the opening 21, and the width of the gas introduction flow path 51 is the width in the direction perpendicular to the central axis of the anode 14 in the cross section. Y is meant.

According to the anode 14 shown in FIG. 12, the lid 40 has a gas introduction channel 51 that extends along the central axis and penetrates the lid 40 in the direction of the central axis, and the tip of the gas introduction channel 51. A wide portion 510 wider than the other portions is formed in a part of the side, and an opening 510A leading to the sealed space C is formed in the distal end surface of the fitting portion 42. In the anode 14 shown in the figure, a heat transfer body capturing space S is formed by the wide portion 510.
Here, according to the anode 14 shown in the figure, the width of the heat transfer body capturing space S is the center axis of the anode 14 in a cross section obtained by cutting the anode 14 along a plane including the center axis and the gas introduction channel 51. The width X of the wide portion 510 in a direction orthogonal to the width of the gas introduction channel 51 means the width Y of the gas introduction channel 51 in the direction orthogonal to the central axis of the anode 14 in the cross section.

The outline of the structure of the discharge lamp of this invention is shown. It is a perspective view which expands and shows the structure of the anode of the discharge lamp of FIG. It is sectional drawing which expands and shows the structure of the anode of the discharge lamp of FIG. FIG. 2 shows an enlarged cross section of the main part of the anode of the discharge lamp of FIG. 1 and a view of the cross section viewed from the AA ′ direction. It is sectional drawing which shows other embodiment of an anode. It is sectional drawing which shows other embodiment of an anode. It is sectional drawing which shows other embodiment of an anode. While expanding and showing the cross section of the principal part of other embodiment of an anode, the figure which looked at the said cross section from the AA 'direction is shown. It is sectional drawing which shows other embodiment of an anode. While expanding and showing the cross section of the principal part of other embodiment of an anode, the figure which looked at the said cross section from the AA 'direction is shown. While expanding and showing the cross section of the principal part of other embodiment of an anode, the figure which looked at the said cross section from the AA 'direction is shown. While expanding and showing the cross section of the principal part of other embodiment of an anode, the figure which looked at the said cross section from the AA 'direction is shown. It is sectional drawing which expands and shows the structure of the anode of the conventional discharge lamp.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Arc tube 11 Arc tube part 12 Sealing part 14 Anode 16 Cathode 17 Electrode core rod 20 Base part 21 Opening 22 Internal space 23 Base part side flat surface 24 Base part side flange part 25 Annular groove 26 Base part side slope 40 Lid part 41 Lid Main Body 42 Insertion Portion 43 Lid Side Flat Surface 44 Lid Side Flange 46 Lid Side Slope 47 Arc-shaped Protrusion 47C Protrusion 48 Recess 49 Connection Hole 50 Groove 51 Gas Introduction Channel S Heat Transfer Body Capture space C Sealed space M Heat transfer body

Claims (3)

One of a pair of electrodes arranged in the arc tube so as to face each other in the tube axis direction of the arc tube has a bottomed cylindrical metal base portion having an opening on the base end side, and an internal space of the base portion. In a discharge lamp having a configuration in which a heat transfer body made of a metal having a melting point lower than that of the metal constituting the base portion is enclosed in a sealed space formed by a metal lid portion inserted into
The electrode extends along the central axis of the electrode from the base end portion of the lid portion toward the sealed space, and communicates with the gas introduction flow channel and along the central axis of the electrode. And a heat transfer body capture space that extends
The discharge lamp characterized in that the heat transfer body capturing space has a width in a direction perpendicular to the central axis of the electrode, as compared with the gas introduction flow path.   The lid portion is formed with a groove portion that is recessed toward the center axis direction of the electrode, and the heat transfer body capturing space is partitioned by the groove portion and an inner wall surface of the base portion. The discharge lamp according to claim 1.   In the base portion, a groove portion that is depressed toward the outer peripheral surface in the radial direction of the base portion is formed at a location facing the lid portion, and the heat transfer is performed by the groove portion and the outer peripheral surface of the lid portion. The discharge lamp according to claim 1, wherein the body capturing space is partitioned.

Images