JP2012243674A - Discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp having an electrode support structure the pullout strength of which is stabilized without being affected by the difference in dimensional accuracy between components, and without requiring fine adjustment work.SOLUTION: An electrode support rod is press fitted in an anode recess 32 provided in the end face 30M of an anode 30, and fitted to the anode 30. Metal foils 80A, 80B are arranged between the electrode support rod and the anode recess 32. The metal foils 80A, 80B are arranged to overlap each other at both edges thereof, with the overlapping parts being located in the circumferential direction at approximately uniform intervals, while having approximately equal widths.

Description

  The present invention relates to a discharge lamp used in an exposure apparatus, a projector, and the like, and more particularly to an electrode support structure for a discharge lamp.

  In a discharge lamp of a short arc type or the like, a glass sealing tube is integrally formed at both ends of an arc tube sealed with an electrode, and an electrode pair (cathode, anode) is disposed facing the arc tube. Each electrode is supported by an electrode support rod extending into the sealing tube, and the electrode support rod is usually fixed to the electrode by press-fitting the electrode support rod into a recess formed at the center of the electrode end. .

  In a short arc type discharge lamp or the like, the electrode size is large and the weight is large, and the discharge lamp is disposed along the vertical direction. In such a lamp structure, there is a problem of dimensional accuracy of the electrode support bar and the electrode recess, and it is difficult to fit the electrode support bar into the electrode recess completely without any clearance. Therefore, a cylindrical metal foil is interposed between the electrode support rod and the electrode recess to increase the fitting strength.

  As a configuration of the metal foil, for example, one cylindrical metal foil with a notch is arranged along the inner wall of the electrode recess, and is pressed against the entire periphery of the electrode support rod to fill the gap (see Patent Document 1). Alternatively, a plurality of arc-shaped metal foils are prepared and spaced apart at equal intervals along the inner wall of the electrode recess (see Patent Document 2).

JP 2004-111235 A JP 2010-15792 A

  The dimensional error, surface roughness, and the like of the electrode recess and the electrode support bar vary from product to product. For this reason, even if a metal foil is interposed, the fitting strength and pull-out strength of the electrode support rod vary. In order to avoid variations, it is necessary to perform fine adjustment work to determine the most appropriate configuration while changing the number of metal foils used and the arrangement configuration many times before press-fitting the electrode support rod. Therefore, the work efficiency of lamp manufacturing is greatly reduced.

  Therefore, it is necessary to press-fit the electrode support rod into the electrode so that there is no variation in the fitting strength between products without fine adjustment work.

  The discharge lamp of the present invention can be configured as, for example, a short arc type discharge lamp, and is disposed in an arc tube, and has an electrode having a cylindrical recess at the end, and a columnar electrode support rod that is inserted into the recess and supports the electrode. With. Such an electrode support structure can be applied to any one electrode or both electrodes of the anode and the cathode.

  The discharge lamp of the present invention includes a plurality of members (hereinafter referred to as interposition members) interposed along the circumferential direction of the recess between the electrode recess and the electrode support rod. The interposition member is disposed between the electrode support bar and the electrode along the inner wall of the recess, and is disposed in pressure contact, and the electrode support bar is fitted into the electrode recess through the interposition member.

  As the interposed member, a ductile thin plate member capable of plastic / elastic deformation can be applied. For example, a metal foil or the like is used. The interposition member may be disposed along the inner wall of the electrode recess before the electrode support rod is press-fitted. For example, the intervention member may be deformed to a shape obtained by curving the plate-like member to some extent using a tool or the like.

  In the present invention, the plurality of interposed members overlap each other so as to overlap each other. As a result, the plurality of interposition members are in contact with each other over the entire inner wall of the electrode recess. Further, in addition to the overlapping arrangement, the overlapping portion between the plurality of interposition members is substantially uniform along the circumferential direction. The interposition members are inserted so that the overlapping widths of the overlapping portions are substantially equal.

  For example, the inner circumference of the concave portion is equally divided, and an intervention member having a similar width may be prepared according to each arc-shaped area. At this time, by configuring the interposed members so that the length of each interposed member is larger than the divided circumferential length, the overlapping portions are equally spaced along the circumferential direction, and the overlapping width is the same. Become.

  A plurality of interposition members are arranged over the entire inner wall of the recess, arranged in a balanced manner with respect to the recess axis, that is, the central axis of the electrode support bar, and overlapped with an equal overlap width to press-fit the electrode support bar When this is done, there is no displacement or displacement of the intervening member, and no bias of the intervening member or local deformation occurs. As a result, the electrode support rod can be press-fitted with the same load regardless of the difference in dimensional accuracy of the product, and the pull-out strength does not vary.

  When the electrode support bar hits the interposition member during the press-fitting of the electrode support bar, the overlapping portion tends to shift due to the force received by the interposition member. It is desirable that there is no overlapping portion in the initial stage of press-fitting the electrode support rod. Therefore, each of the plurality of interposed members is preferably formed in a tapered shape, and the tapered tip end portion is arranged so as to face the electrode recess opening side, that is, the electrode support bar side.

  The number of intervening members is arbitrary, but in consideration of positional displacement and deformation of the intervening member when the electrode support rod is press-fitted, two intervening members having a semicircular cross section, or a semicircular cross section It is desirable to configure with three interposition members. Moreover, although various designs are possible also about the shape of an interposed member, it is good that it is a rectangular shaped interposed member curved along the inner wall of a recessed part.

  For example, when a plurality of intervention members are constituted by first and second intervention members, it is preferable to alternately overlap in consideration of balance. That is, the first intervention member overlaps with the edge outer surface of the second intervention member on one edge inner surface, and overlaps with the edge inner surface of the second intervention member on the other edge outer surface. It is possible to do so.

  On the other hand, in the case where the plurality of interposed members are constituted by the first, second, and third interposed members, in consideration of suppressing the shift at the time of press-fitting a metal foil having a small circumferential width, The mounting members overlap on the outer surfaces of the second and third interposed members on the inner surfaces of both edges, and the second interposed members of the first and second interposed members on the outer surfaces of both edges. Overlapping the edge inner surface, the third intervention member overlaps the edge inner surface of the first intervention member on one edge outer surface, and the edge outer side of the first intervention member on the other edge inner surface It can be made to overlap the surface.

  When press-fitting the electrode support bar, the electrode support bar is divided into three stages of temporary insertion, temporary press-fitting, and main press-fitting in order to confirm whether there is no deviation of the metal foil and the electrode support bar can be inserted without rattling. It is desirable to press fit. Therefore, it is possible to provide the electrode support rod with an insertion portion provided with a tip tapered portion including the tip surface of the support rod and a tapered rear tapered portion toward the tip portion. The taper angle is configured to be larger than the taper angle of the latter-stage taper-shaped portion.

  With such a configuration, when the electrode support rod is inserted into the concave portion up to the tapered end portion, it can be confirmed that there is no problem in the arrangement and overlapping of the metal foil. In particular, by relatively increasing the taper angle of the tip taper portion, it becomes easy to insert the tip portion of the electrode support rod first while reducing the pressure applied to the electrode support rod, and the subsequent second taper shape portion. Smoothly press-fit.

  When the electrode support rod is press-fitted, the gas remaining in the recess is compressed and becomes a reaction force, and it is difficult to insert the electrode support rod until it comes into contact with the bottom of the recess, and the press-fitting load increases. Therefore, it is preferable to form a spiral groove along the axial direction in the insertion portion inserted into the recess of the electrode support rod.

  The method of manufacturing a discharge lamp according to the present invention includes a step of arranging a plurality of plate-shaped interposing members along the inner wall of the recess with respect to the cylindrical recess provided at the end of the electrode, and press-fitting a columnar electrode support rod into the recess. And a method of manufacturing the discharge lamp including the step of fitting the electrode support rod and the electrode, wherein after the electrode support rod is press-fitted, the plurality of interposition members overlap each other at both edges, A plurality of interposition members are arranged and the electrode support rods are press-fitted so that the overlapping portions between the mounting members are arranged substantially evenly apart along the circumferential direction, and the overlapping widths of the respective overlapping portions are substantially equal. .

  According to the present invention, it is possible to provide a discharge lamp having an electrode support structure with a stable pull-out strength without being affected by a difference in dimensional accuracy between components and without performing fine adjustment work.

It is a schematic plan view of the short arc type discharge lamp which is this embodiment. It is a schematic sectional drawing of an electrode support rod and an anode. It is the schematic which showed the electrode, electrode support rod, and metal foil before fitting an electrode support rod to an electrode. It is the schematic diagram which showed the metal foil inserted and interposed in an anode recessed part. It is the anode top view which looked at the state where metal foil was inserted in the anode crevice from the electrode support stick side. It is a top view of the electrode support bar in a 2nd embodiment. It is the figure which showed arrangement | positioning of the metal foil in 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic plan view of a short arc type discharge lamp according to the present embodiment.

  The short arc type discharge lamp 10 is a lamp in which a cathode 20 and a cathode 30 are arranged opposite to each other in a spherical light emitting tube 12 made of quartz glass, and quartz glass sealing tubes 15A and 15B are disposed on both sides of the light emitting tube 12. Are integrally connected so as to face each other.

  Inside the sealing tubes 15A and 15B, parts 60 and 70 for supporting the cathode 20 and the anode 30 and sealing the discharge space 11 in the arc tube 12 (hereinafter referred to as mounting parts) are encapsulated. Mercury and a rare gas are sealed in the discharge space 11.

  As mounting parts 60 and 70, there are provided electrode support rods 40 and 50 which are connected to the cathode 20 and the anode 30 and support the cathode 20 and the anode 30, respectively, and are arranged along the electrode axis (lamp axis) direction. . The electrode support rods 40 and 50 are respectively inserted into cylindrical thick glass tubes in the mount parts 60 and 70 and are held by the electrode side glass tubes.

  The electrode support rods 40 and 50 are electrically connected to an external power supply unit via a conductive member such as a strip-shaped metal foil included in the mount parts 60 and 70. An arc discharge occurs between the arc tube 30 and light is emitted to the outside of the arc tube 11.

  FIG. 2 is a schematic cross-sectional view of the electrode support rod and the anode. Note that the same configuration is provided on the cathode side.

  The cylindrical anode 30 has a tip surface 30S facing the cathode 20 at one axial end, and a cylindrical electrode recess 32 into which the electrode support rod 50 is fitted is formed on the opposite end surface 30M. . The recess 32 is formed coaxially with the axis X of the anode 30, and the length from the opening to the bottom surface 32 </ b> S is determined according to the length of the insertion portion of the electrode support bar 50.

  The electrode support rod 50 has an insertion portion 52 that fits into the electrode recess 32, and the distal end surface of the insertion portion 52, that is, the distal end surface 50 </ b> S of the electrode support rod 50 is located at or near the bottom surface 32 </ b> S of the recess 32. The insertion portion 52 is composed of two tapered portions 52A and 52B.

  The tip tapered portion 52A including the tip surface 50S has a conical shape with a relatively large taper angle, and the inclination angle with respect to the axis of the electrode support bar is set in a range of 15 to 25 degrees (for example, 20 degrees). On the other hand, the rear taper-shaped part 52B integral with the front-end taper-shaped part 52A has a smaller diameter than the support bar main body part 54 held by the electrode-side glass tube. The rear taper-shaped portion 52B has a conical shape with a very small taper angle. For example, the inclination angle with respect to the axis of the electrode support rod is set in a range of 0.1 to 1 degree (for example, 0.4 degree).

  The size of the insertion portion 52 of the electrode support bar 50 is in accordance with the size of the electrode recess 32. When the electrode support bar 50 is press-fitted into the electrode recess 32, the electrode support bar 50 is disposed coaxially with the anode 30. . The length in the axial direction of the tapered end portion 52A is shorter than that of the rear tapered portion 52B.

  Between the insertion portion 52 of the electrode support rod 50 and the electrode recess 32, two metal foils (interposition) are provided in the gap in order to prevent rattling due to the clearance (gap) between the electrode support rod 50 and the recess 32 caused by a dimensional error. Members) 80A and 80B are arranged so as to fill the gap.

  The metal foils 80A and 80B are arc-shaped curved thin plates having a substantially semicircular cross section, and are in pressure contact with the insertion portion 52 of the electrode support rod 50 and the inner wall 32R of the recess 32. Further, as will be described later, the metal foils 80 </ b> A and 80 </ b> B overlap at both edges and are interposed along the entire circumferential direction of the inner wall 32 </ b> R of the recess 32.

  Below, the connection process of an electrode support rod and an anode, the shape of metal foil, and arrangement | positioning structure are demonstrated using FIGS.

  FIG. 3 is a schematic view showing the electrode, the electrode support bar, and the metal foil before the electrode support bar is fitted to the electrode.

  In the electrode support bar 50, a two-stage tapered insertion portion 52 is formed by machining. Then, the metal foils 80 </ b> A and 80 </ b> B are disposed along the inner wall of the electrode recess 32, and then the electrode support rod 50 is press-fitted into the anode 30.

  In the press-fitting step, first, the tip tapered portion 52A is temporarily inserted into the recess 32, and the insertion length of the metal foils 80A and 80B and the electrode support rod circumferential direction position are confirmed. If there is no problem, it is temporarily press-fitted using a tool to a position where a part of the rear tapered portion 52B is inserted, and the presence or absence of rattling of the electrode support bar 50, the degree of straightness, and the overlapping state of the metal foils 80A and 80B are confirmed. . If there is no problem, the electrode support bar 50 is fully press-fitted using a press machine or the like, and the electrode support bar 50 is inserted into the recess 32 within the range of the load limit.

  FIG. 4 is a schematic view showing a metal foil inserted and interposed in the anode recess. FIG. 5 is a top view of the anode as seen from the electrode support rod side with the metal foil inserted in the anode recess. However, the electrode support rod is not shown for illustration.

  The metal foil 80A is formed as a curved thin plate obtained by bending a rectangular metal foil with a tool, and the electrode support rod 50 is press-fitted, whereby a semicircular arc-shaped thin plate is disposed along the inner wall of the electrode recess 32. Is done. The metal foil 80B has the same size and shape.

  The metal foils 80A and 80B have circumferential lengths such that they overlap with the other metal foil 80B at both edges 83A and 83B and 86A and 86B. As shown in FIG. 5, the overlapping is such that the outer surface of the edge 83A and the inner surface of the edge 86A are in contact with each other. On the other hand, on the opposite side, the inner surface of the edge portion 83B and the outer surface of the edge portion 86B are overlapped with each other.

  When inserting the tapered end portion 52A, the metal foils 80A and 80B are arranged in the electrode recess 32 so that the overlapping widths of the metal foils 80A and 80B are substantially equal at both edges, and then temporarily press-fitted. If not, the electrode support bar 50 is press-fitted into the anode recess 32. As a result, the overlapping portions of the metal foils 80A and 80B are arranged at substantially equal intervals along the circumferential direction of the concave portion 32, and the overlapping widths are substantially equal and fixed in contact.

  When the electrode support bar 50 is press-fitted, the metal foils 80A and 80B are disposed so as to be interposed over the entire periphery of the insertion part 52 of the electrode support bar 50 while overlapping each other at the base part. Thus, the electrode support bar 50 is firmly fitted to the anode 30 through the electrometal foils 80A and 80B.

  A discharge lamp is manufactured through such joining of the electrode support rod and the electrode. In addition, about processes other than joining, a discharge lamp is manufactured according to a conventionally well-known process. That is, the arc tube and the sealing tube are formed while heat-treating the glass tube, the mounting parts are inserted into the sealing tube and the electrodes are arranged in the arc tube, and then the diameter of the sealing tube is reduced by heating.

  Thus, according to the present embodiment, the electrode support bar 50 is press-fitted into the recess 32 provided in the end face 30M of the anode 30, and thereby the electrode support bar 50 is fitted to the anode 30. Metal foils 80 </ b> A and 80 </ b> B are interposed between the electrode support rod 50 and the recess 32. And metal foil 80A, 80B mutually overlaps in the both edges, the overlap part is located in a substantially equal space | interval along the circumferential direction, and the overlap width is substantially equal.

  Thus, by arranging the two metal foils generally along the circumferential direction of the inner wall of the recess, the bending process becomes easier as compared with the one metal foil, and the electrode support rods can be arranged by overlapping them. When press-fitting, the two metal foils are pressed against each other and there is no possibility of shifting from each other.

  In addition, the metal foils can be evenly arranged in the circumferential direction with the same overlapping width of the metal foil, so that it is possible to receive a balanced force when the electrode support rod is pressed in, and the metal foil can be press-fitted without any deviation. Regardless of the difference, the electrode support rod can be press-fitted with the same load without fine adjustment work, and the pull-out strength does not vary.

  In particular, by contacting the overlapping portions of two metal foils alternately on the inner and outer surfaces, the electrode support rod can be pressed into the metal foil in a state where the metal foil is stably arranged by temporary press-fitting. The applied force can also be balanced. Further, since the metal foil is temporarily fixed at the tip tapered portion by temporary insertion, the metal foil is not displaced when the electrode support rod is press-fitted.

  Next, the discharge lamp which is 2nd Embodiment is demonstrated using FIG. 6, FIG. In the second embodiment, three metal foils are used and a groove is formed in the insertion portion of the electrode support bar. About another structure, it is substantially the same as 1st Embodiment.

  FIG. 6 is a plan view of an electrode support bar according to the second embodiment.

  The insertion portion 152 of the electrode support bar 150 includes a tip tapered portion 152A including a tip surface 150S and a rear taper portion 152B. Here, there is little difference in diameter between the insertion portion 152 and the support portion main body portion 154.

  A spiral groove 160 is formed along the axial direction in the rear tapered portion 152B of the insertion portion 152. Due to the spiral groove 160, the gas accumulated in the anode recess during the press-fitting of the electrode support rod 150 can be removed.

  FIG. 7 is a view showing the arrangement of the metal foil in the second embodiment.

  Each of the metal foils 180A, 180B, and 180C is configured as a curved thin plate having a semicircular cross section having a circumferential length that is approximately 1/3 of the circumference. The metal foils 180A, 180B, and 180C are interposed over the entire inner surface of the recess 132 of the anode 130, with both edges overlapping each other.

  Here, the metal foil 180A is in contact with the metal foils 180B and 180C on the inner surface at both edges. On the other hand, both edges of metal foil 180B are in contact with metal foils 180A and 180C on the outer surface. The metal foil 180C is in contact with the metal foil 180B at the edge inner surface and is in contact with the metal foil 180A at the other edge outer surface.

  In the case of the three metal foils 180A, 180B, 180C, the circumferential length is shortened and the overlapping portion increases, and the metal foil is liable to be displaced at the time of press-fitting. By contacting and contacting one sheet with the outer surface at both edges, misalignment of the metal foil is prevented.

  The overlapping widths along the circumferential direction of the metal foils 180A, 180B, 180C are substantially equal. Further, the metal foils 180A, 180B, and 180C are arranged uniformly in the circumferential direction. When the electrode support bar 150 shown in FIG. 6 is press-fitted into the electrode recess 132, the electrode support bar 150 is fitted and fixed to the anode 130. In the case of three metal foils, the circumferential lengths of the metal foils are shortened and overlapping portions are increased, so that the electrode support rods are prevented from rattling and the straightness is further improved.

  The shape and number of metal foils are not limited to the configurations shown in the first and second embodiments, and tapered metal foils can also be used. Moreover, it is a member other than a metal, and may be a curved thin plate member having an arcuate cross-sectional arc shape. A method other than the above method may be applied as a method for joining the electrode support rod and the electrode.

  When the electrodes are actually manufactured by connecting the electrodes to the electrode support bars as in the first and second embodiments, there is no variation between the products in terms of the pulling strength of the electrode support bars and the anode. For example, when preparing several electrode support rods and anodes, measuring the actual dimensions, and then measuring the pull-out strength after connection and the extra dimensions after press-fitting, the size of the electrode support bars with dimensional errors, Regardless of the size of the anode recess, the excess dimension after press-fitting (the distance between the bottom surface of the anode recess after the main press-fitting and the tip surface of the electrode support rod) is eliminated and the press-fitting is complete. The pull-out strength is the same value and there is no variation between products. In addition, the pressure during the main press-fitting and the surplus dimensions after the press-fitting both have the same value, and there is no need to make fine adjustments in the number, arrangement, press-fitting load, etc. of the metal foil when the electrode support bar is press-fitted. And the drawing strength more than before is obtained.

DESCRIPTION OF SYMBOLS 10 Discharge lamp 20 Cathode 30 Anode 32 Recess 40, 50 Electrode support rod 52 Insertion part 52A Tip taper part 52B Rear taper part 80A, 80B Metal foil 83A, 83B Edge

Claims (8)

An electrode disposed in the arc tube and having a cylindrical recess at the end;
A columnar electrode support rod that is inserted into the recess and supports the electrode;
A plurality of interposed members interposed along the circumferential direction of the recess between the recess and the electrode support rod;
The plurality of interposed members overlap each other at both edges;
The discharge lamp characterized in that overlapping portions between the plurality of interposed members are arranged at substantially equal intervals along the circumferential direction, and the overlapping widths of the respective overlapping portions are substantially equal.   The discharge lamp according to claim 1, wherein the plurality of interposed members are configured by two or three interposed members. The plurality of interposed members are constituted by first and second interposed members,
The first intervention member overlaps with the edge outer surface of the second intervention member on one edge inner surface, and the edge inner surface of the second intervention member on the other edge outer surface. The discharge lamp according to claim 1, wherein the discharge lamps overlap. The plurality of intervention members are constituted by first, second, and third intervention members,
The first intervention member overlaps the outer surface of the edge of the second and third intervention members on the inner surface of both edges;
The second intervention member overlaps the inner edge surface of the first and second intervention members on the outer surface of both edges;
The third intervention member overlaps with the edge inner surface of the first intervention member on one edge outer surface, and overlaps the edge outer surface of the first intervention member on the other edge inner surface. The discharge lamp according to any one of claims 1 and 2.   The discharge lamp according to any one of claims 1 to 4, wherein the plurality of interposed members are made of metal foil. The electrode support rod has an insertion portion provided with a tip tapered shape portion including a support rod tip surface and a rear taper shape portion that tapers toward the tip taper shape portion,
The discharge lamp according to any one of claims 1 to 5, wherein a taper angle of the tip tapered portion is larger than a taper angle of the rear taper portion.   The discharge lamp according to any one of claims 1 to 6, wherein the electrode support bar has a spiral groove formed along an axial direction in an insertion portion inserted into the recess. A step of arranging a plurality of plate-shaped interposition members along the inner wall of the recess, with respect to the cylindrical recess provided at the end of the electrode;
A method of manufacturing a discharge lamp, comprising the step of press-fitting a columnar electrode support rod into the recess and fitting the electrode support rod and the electrode together,
After the electrode support rod press-fitting, the plurality of interposition members overlap with each other at both edges, and the overlapping portions between the plurality of interposition members are arranged at substantially equal intervals along the circumferential direction. The discharge lamp manufacturing method is characterized in that the plurality of interposition members are arranged and the electrode support rods are press-fitted so that the overlapping widths of the electrodes are substantially equal.

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