JP5036361B2 - Discharge lamp using electrode having heat dissipation structure of stepped groove - Google Patents

Description

  The present invention relates to a discharge lamp that generates ultraviolet rays, and more particularly, to a discharge lamp using a step-grooved heat dissipation structure and an electrode with a small temperature rise, and a method for manufacturing the electrode.

  Conventionally, as a light source for forming a semiconductor wiring pattern, a short arc type discharge lamp that generates ultraviolet rays or the like is generally used. The discharge lamp is lit in a vertical state with the anode up or down. The anode in the lighting state becomes high temperature due to collision of electrons from the cathode, and is evaporated and consumed. Since the particles evaporated from the electrode are carried by thermal convection and adhere to the inner wall of the discharge lamp, the inner tube wall on the upper side from the central portion of the arc tube is blackened. The electrodes of the discharge lamp include a cathode and an anode, but in the following description, these may be simply referred to as electrodes.

  Suppressing the high temperature of the anode when the short arc type discharge lamp is turned on can reduce the evaporation of the electrode constituent material from the tip of the anode, reduce the wear and thermal deformation of the electrode tip, and the service life of the lamp Can be extended. For this purpose, the amount of heat released from the electrode by radiation may be increased. Specifically, a V-shaped heat radiation groove is formed on the side surface of the electrode to increase the surface area of the anode, and heat radiation from the electrode is increased to lower the electrode temperature.

  FIG. 5 shows a conventional heat dissipation structure. FIG. 5A is an enlarged step view of the heat dissipation structure with a wide V-shaped groove opening. FIG. 5B is an enlarged cross-sectional view of the heat dissipation structure in which the opening of the rectangular groove is narrow. 5A and 5B, a V-shaped groove portion 60 and a rectangular groove portion 70 are heat dissipation structures formed by laser processing. The top surfaces 61 and 71 are surfaces that are not grooved. The bottom surfaces 62 and 72 are the bottom surfaces of the grooves. The side surfaces 63 and 73 are side surfaces of the groove. The deformed heat dissipation structure 74 is a heat dissipation structure deformed by an external force. As shown in FIG. 5A, the side surface 63 of the V-shaped groove portion 60 has a V-shaped width extending from the bottom surface 62 toward the top surface 61. The V-shaped groove 60 is less likely to deform the heat dissipation structure than the rectangular groove 70. However, the V-shaped groove has less increase in the surface area of the entire electrode.

  As shown in FIG. 5B, the side surface 73 of the rectangular groove 70 is substantially parallel between the bottom surface 72 and the top surface 71. Compared with the V-shaped groove 60, the heat dissipation structure of the rectangular groove 70 is easily deformed. However, the rectangular groove has a larger increase in the surface area of the entire electrode. When the heat dissipation structure is deformed, the wall of the groove comes into contact with the adjacent wall as in the deformed heat dissipation structure 74. In this case, the deformed part and its peripheral part are in a high temperature state, and the electrode may be abnormally consumed. Below are some examples of prior art related to this.

  The “anode for a rare gas-filled high-pressure discharge lamp” disclosed in Patent Document 1 is a tungsten anode having a cooling groove of 1 to 3 mm on the outer peripheral surface as shown in FIG. The angle between the sides of the cooling groove is 90 °. The anode outer peripheral surface is a sintered metal layer having a high heat dissipation property. The “discharge lamp anode” disclosed in Patent Document 2 is an electrode of a cylindrical tungsten rod in which a groove parallel to the axial direction is cut into a side circumferential surface as shown in FIG. The depth of the groove is 1-7% of the cylinder diameter. The angle of the groove is 60-90 °. As shown in FIG. 5 (e), the “fishing discharge lamp” disclosed in Patent Document 3 includes an anode provided with a groove deeper than the width in the body. The depth of the groove is 6 mm and the width is 3 mm. The diameter of the front and rear end faces is 12 mm, the outer diameter of the body is 30 mm, and the total length of the anode is 40 mm. As shown in FIG. 5 (f), the “short arc discharge lamp” disclosed in Patent Document 4 includes an anode in which a plurality of grooves that are shallow on the distal end side and deep on the proximal end side are carved on the peripheral surface. I have. As shown in FIG. 5G, the “short arc type high-pressure discharge lamp” disclosed in Patent Document 5 includes an electrode having a groove formed on a side surface. The depth of the groove is within 12% of the electrode diameter. The depth D of the groove is at least twice the pitch P of the groove. Patent Documents 6 and 7 disclose semiconductor laser processing techniques. Non-Patent Documents 1 and 2 describe various techniques related to the basics and applications of laser processing.

Japanese Patent Publication No. 39-011128 Japanese Utility Model Publication No.54-132975 Japanese Utility Model Publication No. 60-048663 Japanese Utility Model Publication No. 60-110973 JP 2002-117806 JP JP 63-278368 A Japanese Patent No. 2810435 (Japanese Patent Laid-Open No. 01-225928) Edited by Laser Association: “Laser Applied Technology Handbook” (Asakura Shoten, published in 1984) Edited by Hiromichi Kawasumi: “Laser Processing Technology” (CMC, 2001)

  However, a conventional discharge lamp using an electrode having a V-shaped heat radiation groove has the following problems. In the V-shaped heat radiation groove having a large side opening angle and a low groove density, the heat radiation effect of the electrode is small. In a rectangular heat radiation groove having a small opening angle on the side surface and a high groove density, the heat radiation portion is easily deformed.

  An object of the present invention is to solve the above-mentioned conventional problems, and to increase the surface area while sufficiently maintaining the strength of the electrode of the discharge lamp, thereby extending the life of the lamp.

  In order to solve the above-described problems, in the present invention, a heat dissipation structure for a discharge lamp having an electrode having a heat dissipation structure on the surface is provided inside the discharge vessel, and a plurality of parallel structures having a V-shaped cross section and stepped side surfaces. It was set as the structure which consists of a groove | channel. The number of steps on the stepped side surface is three, and the height of the next step after the top step is more than half of the height of the top step. Alternatively, the number of steps on the stepped side surface is two, and the height of the intermediate step is more than half of the height of the upper step. The groove has a ring shape perpendicular to the axis of the electrode. Or it is a straight line parallel to the axis of the electrode.

  By comprising as mentioned above, since the thermal radiation effect can be heightened, maintaining the intensity | strength of the thermal radiation structure of an electrode, the lifetime of a discharge lamp can be extended.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS.

  An embodiment of the present invention is a discharge lamp using an anode having a heat dissipation structure composed of a plurality of parallel ring-shaped grooves having a V-shaped cross section and two or three stepped side surfaces.

  FIG. 1 is an external view of a discharge lamp using an anode having a heat dissipation structure with stepped grooves, which is a discharge lamp according to an embodiment of the present invention. In FIG. 1, an anode 1 is a positive electrode. The cathode 2 is a negative electrode. The internal lead bar 3 is a member that supplies power while supporting an electrode. The metal foil 4 is a member that electrically connects the internal lead bar and the external lead bar. The sealing tube portion 5 is a portion that hermetically seals the valve. The external lead bar 7 is a member that feeds power from the base through the metal foil to the electrode. The light emitting unit 9 is a part that emits light by discharge between the electrodes. The bulb portion 10 is a glass member that seals an electrode to form a discharge space. The base 20 is a member for mechanically holding the lamp and supplying power. The heat dissipation structure 40 is a heat dissipation structure with stepped grooves provided on the circumferential side surface of a cylindrical electrode.

  As shown in FIG. 1, the discharge lamp includes a bulb portion 10 composed of a light emitting portion 9 and two sealing tube portions 5, an anode 1 and a cathode 2 disposed opposite to each other in the light emitting portion 9, Sealing that supports the cathode 2 and energizes the inner lead rod 3, the outer lead rod 7, and connects the inner lead rod 3 and the outer lead rod 7 with the conductive metal foil 4 to hermetically seal. It is comprised by the pipe part 5. FIG. A base 20 is fixed to the sealing tube portion 5 on the anode side. A base 20 is also fixed to the sealing tube portion 5 on the cathode side. The discharge lamp is fixed to the light source device via the base 20.

  FIG. 2 is an enlarged view of an anode having a step-shaped groove heat dissipation structure used in a discharge lamp in an embodiment of the present invention. FIG. 2A is an external view of the anode. FIG. 2B is a cross-sectional view taken along the line BB in FIG. 2A and 2B, the tip surface 31 is a surface that discharges with the cathode, and is one end surface of the columnar electrode. The body surface 30 is a circumferential side surface of a cylindrical electrode. The tip side taper surface 32 is a surface that connects the tip surface 31 and the body surface 30. The heat dissipating structure 40 is a step-shaped groove heat dissipating structure provided in at least a part of the body surface 30. The back surface 34 is the other end surface of the cylindrical electrode. The back side taper surface 33 is a surface connecting the back surface 31 and the body surface 30. The electrode hole 35 is a hole into which the internal lead bar is fitted. The outer diameter D1 is the maximum outer diameter on the body surface of the anode. The outer diameter D2 is the maximum outer diameter of the heat dissipation structure provided on the body surface of the anode.

  As shown in FIGS. 2A and 2B, the anode has a substantially cylindrical shape. There are a front end surface 31, a front end side taper surface 32, a body surface 30, a back side taper surface 33, and a back surface. The body surface 30 is provided with a heat dissipation structure 40. By inserting the internal lead rod into the electrode hole 35 provided in the back surface 34, the electrode is held in the discharge space. Since the heat dissipating structure 40 is a part that emits a large amount of heat, the heat of the anode is efficiently radiated to lower the temperature when the lamp is lit.

FIG. 3 is a partially enlarged view of the cross section of the heat dissipation structure of the stepped groove of the electrode used in the discharge lamp in the embodiment of the present invention. FIG. 3A shows a heat dissipation structure with three steps of stepped grooves. FIG. 3B shows a heat dissipation structure with two stepped grooves. 3C, 3D, and 3E are other shapes of the heat dissipation structure of the two-step staircase groove. In FIG. 3A, a top surface 41 is a surface not subjected to laser processing and serves as a body surface of the electrode. The bottom surface 42 is a bottom surface of the heat dissipation structure. The side surface 43 is a surface substantially parallel to the dug direction. The first step surface 44 is a substantially L-shaped groove in the first step from the bottom surface of the heat dissipation structure. The second step surface 45 is a substantially L-shaped groove in the second step from the bottom surface of the heat dissipation structure. The height H ₁ is the height of the top surface with respect to the bottom surface. The height H ₂ is the height of the second step surface with respect to the bottom surface. The height H ₃ is the height of the first step surface with respect to the bottom surface. That is, H ₁ > H ₂ > H ₃ .

As shown in FIG. 3 (A), the heat radiation structure 40 having a three-step staircase groove has a number of step-like shapes each having a top surface 41, a first step surface 44, a second step surface 45, a bottom surface 42, and a side surface 43. It consists of a groove. The groove is formed in the circumferential direction on the body surface of the electrode. A substantially L-shaped groove is formed stepwise from the bottom surface 42 of the heat dissipation structure 40 to the opening side. The relationship between the heights of the stairs is H ₂ ≧ H _1/2 . More preferably, the H ₂ ≧ 2H _1/3.

The reason for this is as follows. When the top stage surface height (H ₁₎ and the second step surface height difference between the _{(H 2) (H 1 -H} 2) is large, the effect of preventing the deformation of the heat dissipation structure is reduced. Further, when the height of the top-level portion (H ₁₎ and the height of the first step surface difference between the _{(H 3) (H 1 -H} 3) is large, the volume increases dug toward the central axis of the electrode , Heat dissipation due to convection from near the bottom increases.

In FIG. 3B, a top surface 51 is a surface not subjected to laser processing and serves as a body surface of the electrode. The bottom surface 52 is a bottom surface of the heat dissipation structure. The side surface 53 is a side surface of the dug groove. The first step surface 54 is a substantially L-shaped groove in the first step from the bottom surface of the heat dissipation structure. The height H ₁ is the height of the top surface with respect to the bottom surface. The height H ₄ is the height of the first step surface with respect to the bottom surface. That is, H ₁ > H ₄ .

As shown in FIG. 3B, the two-step staircase groove heat dissipation structure 50 includes a staircase groove including a top surface 51, a first step surface 54, a bottom surface 52, and a side surface 53. The groove is formed in the circumferential direction on the body surface of the electrode. An L-shaped groove is formed in a staircase on the opening side with the center of the bottom surface as the axis of symmetry. Here, H ₄ ≧ H _1/2 . More preferably, the H ₄ ≧ 2H _1/3. However, the first step surface 54 should not be brought too close to the top surface 51. The reason for this is as follows. If the difference between the height of the top step surface and the height of the first step surface (H ₁ −H ₄ ) is too large, the effect of preventing the heat dissipation structure from being deformed is reduced. In addition, if the difference between the height of the top step surface and the height of the first step surface (H ₁ −H ₄ ) is too small, the volume dug into the central axis side of the electrode becomes small, and heat dissipation due to convection from the bottom surface is reduced. Less.

  Next, a modified example of the heat dissipation structure will be described with reference to FIGS. FIG. 3C illustrates a heat dissipation structure in which an L-shaped groove is provided only on one side surface. The heat dissipation structure 50A is generally the same as the heat dissipation structure 50, except that a substantially L-shaped groove 54A is provided only on one side surface. FIG. 3D shows a smooth heat dissipation structure. The heat dissipation structure 50B is roughly the same as the heat dissipation structure 50, but has a smooth surface. Until now, in order to explain the structure simply, the heat dissipation structure is indicated by a rectangle, but it is desirable that the actual heat dissipation structure be smooth in this way.

  FIG. 3E shows a heat dissipation structure including a substantially J-shaped groove. When the laser irradiation diameter is thin, it may be a substantially J-shaped groove. Also in this case, it is desirable that the surface be smooth. The reason why it is preferable to smooth the surface of the heat dissipation structure is as follows. Depending on the irradiation condition of the laser beam, there may be an acute angle at the boundary between the step surface and the side surface. If the corner portion is used as it is for the electrode of the discharge lamp, the corner portion is peeled off from the electrode material and released into the discharge space, causing the discharge lamp to become black and the lamp to have a short life. There is a case. Therefore, the heat dissipation structure is smoothed. However, if the surface is too smooth, the surface area of the heat dissipation structure does not increase so much, so the power of the laser beam is set to an appropriate value according to the electrode material and the like.

  Next, a method for manufacturing a heat dissipation structure will be described with reference to FIG. Since the basic technique regarding laser processing is well known, detailed description is omitted, but if necessary, refer to Patent Documents 6 and 7, Non-Patent Documents 1 and 2, and the like. FIG. 4 shows the order in which the electrodes are dug by the laser beam. FIG. 4A is an enlarged cross-sectional view showing a first manufacturing example of the heat dissipation structure. FIG. 4B is an enlarged cross-sectional view illustrating a second manufacturing example of the heat dissipation structure. FIG. 4 (3) is an enlarged cross-sectional view showing a third manufacturing example of the heat dissipation structure. A first manufacturing example of the heat dissipation structure will be described with reference to FIG. First, in (A), a substantially V-shaped groove is dug by irradiating the electrode with laser light while rotating the cylindrical electrode on the axis. Next, in (B) to (E), laser light is similarly irradiated to dig a plurality of substantially L-shaped grooves on the slopes of the grooves produced in (A). Here, the order of (B) to (E) in which other grooves are dug in the slopes of the grooves prepared in (A) is not particularly limited. In addition, it is preferable to appropriately set the output characteristics of the laser when the groove formed in (A) is created and when other grooves are dug.

  For example, in the case of digging a V-shaped groove in (A), laser light is irradiated so as to be perpendicular to the body surface of the electrode. In (B) to (E), other L-shaped grooves When digging up, it is better to irradiate the laser beam so as to be perpendicular to the slope of the V-shaped groove. In the case of digging a V-shaped groove in (A), the laser beam irradiation diameter may be thick, but in the case of digging other L-shaped grooves in (B) to (E). For this reason, it is better to make the irradiation diameter of the laser light thinner. Smoothing smoothes the surface of the heat dissipation structure of the electrode while continuously moving the laser beam in the axial direction of the electrode while the electrode rotates about the cylindrical central axis. Further, smoothing may be performed by electrolytic polishing or high-temperature heat treatment in vacuum.

  With reference to FIG. 4B, a second manufacturing example in which the heat dissipation structure is formed by laser will be described. In (A), while rotating the cylindrical electrode around the axis, the electrode is irradiated with laser light to dig a groove, and then the laser light is shifted in the axial direction of the electrode, and further from (B) to (E) As shown, dig a ditch. In this embodiment, the laser beam is irradiated while being moved stepwise in the axial direction. However, while rotating the cylindrical electrode on the axis, the laser beam is irradiated to the electrode, and the irradiation position of the laser beam is set on the electrode. A smooth step-shaped groove heat dissipation structure may be obtained by continuously moving in the axial direction.

  A third manufacturing example of the heat dissipation structure will be described with reference to FIG. After digging a large-diameter groove with laser light in (A), digging a medium-diameter groove with laser light in (B), and digging a small-diameter groove with laser light in (C). Produced. In this embodiment, the laser beam irradiation diameter is changed stepwise from large to small and the groove is dug, but the laser light irradiation diameter may be changed stepwise from small to large. A smooth step-shaped groove heat dissipation structure may be obtained by continuously irradiating the electrode with laser light while rotating the cylindrical electrode around the axis and continuously changing the irradiation diameter of the laser light. The heat dissipation structure is produced by the above method.

  In the present embodiment, the circumferential direction of the electrode has been described, but the similar heat dissipation structure may be in the axial direction of the electrode. Although the anode has been described as an example, the same effect can be obtained if a heat dissipation structure is provided in the body of the cathode.

  As described above, in an embodiment of the present invention, a discharge lamp is an anode having a heat dissipation structure including a plurality of parallel ring-shaped grooves having a V-shaped cross section and side surfaces of two or three stepped grooves. Therefore, the heat radiation effect can be enhanced while maintaining the strength of the electrode heat radiation structure, and the life of the discharge lamp can be extended.

  The discharge lamp of the present invention is optimal as a short arc discharge lamp for generating ultraviolet rays. The electrode having this heat dissipation structure can also be applied to lamps for other light sources.

It is an external view of the discharge lamp in the Example of this invention. It is an enlarged view of the anode of the discharge lamp in the Example of this invention. It is an expanded sectional view of the thermal radiation structure provided in the electrode of the discharge lamp in the Example of this invention. It is an expanded sectional view which shows the preparation methods of the thermal radiation structure provided in the electrode of the discharge lamp in the Example of this invention. It is a figure which shows the expanded sectional view of the conventional heat dissipation structure of an electrode, and the example of the electrode which has the conventional heat dissipation structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Anode 2 Cathode 3 Internal lead rod 4 Metal foil 5 Sealing tube portion 7 External lead rod 8 Silver solder 9 Light emitting portion
10 Valve section
20 base
30 Torso surface
31 Tip surface
32 Tip side taper surface
33 Back taper surface
34 Rear
35 Electrode hole
40, 50, 50A, 50B, 50C Heat dissipation structure
41,51,61,71 Top surface
42,52,62,72 Bottom
43,73,63,73 side
44,54,54A First step surface
45 Second step
60 V-shaped groove heat dissipation structure
70 Heat dissipation structure of rectangular groove
74 Deformed heat dissipation structure

Claims (6)

In the discharge lamp having an electrode having a heat radiation structure on the surface inside the discharge vessel, the heat dissipation structure, cross-section comprises a plurality of parallel grooves having a stepped side surface is substantially V-shaped, said stepped The side surface includes a plurality of grooves having a substantially L-shaped or substantially J-shaped cross section, and the opening angle at which the cross section opens from the step surface of the substantially L-shaped or substantially J-shaped groove is substantially equal to the cross section. A discharge lamp characterized by being smaller than an opening angle opened from a bottom surface of a V-shaped groove . Number of stage surface composed of the substantially L-shaped or substantially J-shaped groove, the discharge lamp according to claim 1, characterized in that a two-stage or three-stage including Itadakidan surface. The number of steps of the substantially L-shaped or substantially J-shaped groove is 3 steps including the top step surface , and the height of the next step surface of the top step surface is the height of the top step surface . The discharge lamp according to claim 2, wherein the discharge lamp is more than half of the discharge lamp. The number of steps of the step surface including the substantially L-shaped or substantially J-shaped grooves is two steps including the top step surface, and the next step surface height of the top step surface is the height of the top step surface . 3. The discharge lamp according to claim 2, wherein the discharge lamp is half or more. 2. The discharge lamp according to claim 1, wherein the substantially V-shaped groove has a ring shape perpendicular to the axis of the electrode. The discharge lamp according to claim 1, wherein the substantially V-shaped groove is a straight line parallel to the axis of the electrode.

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