Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J61/00—Gas-discharge or vapour-discharge lamps
  • H01J61/02—Details
  • H01J61/04—Electrodes; Screens; Shields
  • H01J61/06—Main electrodes
  • H01J61/073—Main electrodes for high-pressure discharge lamps
  • H01J61/0732—Main electrodes for high-pressure discharge lamps characterised by the construction of the electrode
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
  • H01J9/02—Manufacture of electrodes or electrode systems

Definitions

• the invention relates to an electrode for a high pressure discharge lamp according to the preamble of claim 1.
• Such electrodes are particularly suitable for high pressure discharge lamps ⁇ with ceramic discharge vessel suited.
• WO 2005/062343 discloses an electrode for a high pressure discharge lamp in which a sublimation laser is used to make a hole in the head of the electrode.
• the electrode for ei ⁇ ne high-pressure discharge lamp, cut from a rod or pin in one piece, with an electrode head as a first segment and a shaft as a second segment, the electrode has an asymmetric shape, which was prepared by means of sublimation.
• it can be used to make a head that is designed helmet-like, with side wall surfaces of the head are removed.
• Another embodiment is that a ball portion is removed parallel to the longitudinal axis of the shaft, wherein the cutting edge of the ball portion coincides in particular with an extension of a shaft edge.
• the head may be shaped as an ellipsoid or or paraboloid.
• the transition between the head and the shaft may additionally have an undercut.
• the shaft of the electrode is pier-like provided with longitudinally parallel grooves.
• the invention relates as described above also to a discharge vessel for a high pressure discharge lamp having at least one electrode.
• a preferred application of these electrodes in a discharge vessel of ceramic material, in particular Al 2 O 3, manufactured, and unilaterally ver ⁇ is closed.
• Such discharge vessels are used in particular in high-pressure discharge lamps, in particular with metal halide filling.
• the invention further relates to a method for producing an electrode by means of a laser, comprising the following steps:
• a cylindrical rod or pin of refractory material in particular tungsten, alloys with tungsten, or TaC;
• Such a shape is, for example, a helmet-like head having a notch, or a helmet-like head having a circumferential transverse slot.
• the shaft of the electrode can be made complex, in particular pier-like provided with longitudinal grooves.
• Another preferred form is a head that has a mushroom-like shade.
• Another aspect of the invention is a method of making such complex shapes.
• Essential for this is the use of a sublimation laser for shaping the electrode.
• a sublimation laser for shaping the electrode.
• a laser which has a high radiation density which is at least sufficient to sublime tungsten.
• the high density of radiation must be sufficient to bring the Elect ⁇ -electrode material in the processing and shaping of fes ⁇ th directly into the gaseous state.
• This can be a sufficiently powerful Nd: YAG laser or CO2 laser.
• a preferred aspect is that it provides ⁇ ⁇ from reaching short pulses of more than 1 microseconds duration and provides the necessary energy density to sublimate at least tungsten.
• a typical repetition rate is 5 to 50 kHz.
• This electrode is particularly suitable for
• Discharge vessels are housed. such
• Discharge vessels are used for metal halide lamps.
• FIGS. 1-9 show an electrode for a high-pressure discharge lamp in various embodiments
• FIG. 10 shows a high-pressure discharge lamp with such an electrode.
• FIG. 1 An embodiment of an electrode 1 is shown in FIG. 1. It has a cylindrical shaft 2 and a ball head 3. The rounding off of the ball head takes place by means of sphering by means of a powerful Nd: YAG laser (arrow). The electrode is made in one piece from tungsten.
• FIG. 2 A further embodiment of an electrode 1 is shown in FIG 2.
• a solid piece of tungsten electrode 1 is shown in Figure 2a, which was initially produced as a Ku ⁇ gelkopf electrode as in FIG. 1
• it is further processed by a special sublimation laser the symmetrical ball head 3 like a helmet narrowed at the two sides parallel to the shaft, so that lateral wall pieces are removed.
• the discharge-side upper surface 4 can be adjusted with the Sublimationslaser a specially ⁇ le curvature.
• the electrode described in FIG. 2a is further processed by creating a slot 6 with a sublimation laser at the tip of the helmet 3 '.
• the electrode described in FIG. 2a is further processed by producing a bore 7 with a sublimation laser at the tip of the helmet 3 '.
• FIG. 3 shows the shaping for an electrode 10 with a cylindrical head 11.
• the electrode is made in one piece from solid material.
• figure 3a shows how the shaft 12 is removed from an originally cylindrical rod by means of the sublimation laser.
• the sublimation laser can be used again to produce according to Figure 3b, a circumferential groove 13.
• a transverse slot 14 can also be produced on the head.
• a central bore 15 can be produced on the head.
• the sublimation laser can also be used to provide the head with a plurality of punctures 16, see Figure 3e.
• FIGS. 4a to 4e show the associated cross sections A - A to E - E through the electrodes of FIG.
• FIG. 5 shows a massive ball head electrode 20 ge shows ⁇ which has been first prepared as in FIG. 1 Thereafter, however, there is still a one-sided flank removal by a sublimation, so that the ball head 21 only on one side over the shaft 22 protrudes, see Figure 5a, or on one side 24 protrudes narrower than on the other side 26, see ⁇ gur 5b.
• FIG. 6 shows an electrode 30, which is produced in one piece from a rod as in FIG.
• An additional shaping in an asymmetrical manner namely the head 31 as an ellipsoid or the like, is achieved after the ball head has been formed by a sublimation laser processing the head 31, in particular by means of laser firing and / or by forming the head below the tungsten pin Sublimation laser is positioned.
• Figure 7 shows a solid one-piece pin electrode 35 made of tungsten. It is made of a W-pin or rod of originally constant diameter. It is the original diameter of the pin on the head 36 is obtained as a cylindrical head, but removed in the region of the shaft 37 by grooves 38, see Figure 7a. Four grooves 38 are recessed longitudinally parallel in the shaft, so that its heat capacity is reduced. a cross section through the shaft 37 shows Figure 7b.
• FIG. 8 shows a conical-head electrode 40 similar to that described in DE 202006004567. This is made of a solid one-piece rod. At the head 41, the original diameter of the rod has been preserved. The head tapers conically 42 in the direction of shaft 43. The diameter of the actual shaft 43 is significantly smaller than the maximum diameter of the head 41.
• the removal of the material can also be carried out according to the invention best with the aid of a sublimation laser. So far, only the possibility of milling is known.
• the advantage of sublimation laser processing is that the surfaces can be cut more cleanly, that the electrode can be processed without contact and that the shaping can be realized much more precisely. This advantage exists over thermal processes of all kinds, as well as against mechanical and chemical processes.
• FIG. 1 shows a conical-head electrode 40 similar to that described in DE 202006004567. This is made of a solid one-piece rod. At the head 41, the original diameter of the rod has been preserved. The head tapers conically 42 in the direction of shaft 43. The diameter of the
• FIG. 9 shows an electrode 50 which can likewise be produced again from the blank of FIG. 1 by further processing.
• the shaft 51 is cylindrical
• the head 52 has the shape of a mushroom shield. In cross section, the contour of the head can be described as a parabola.
• the screen edge 53 can be cut straight or swung out as shown.
• 10 shows a discharge vessel closed at one end 60 for a high pressure discharge lamp. It is preferably made of ceramic.
• CKEN two electrodes 62 that are asymmetric to each other, as in figure 5.
• such electrodes had complicated mechanically together quantitative ⁇ sets or be machined from a block, see DE-A 36 40 990. With the new non-contact method using Sublimationslaser can be a variety of three-dimensional shapes prepare precisely.
• the head 63 of the electrode has at least approximately the shape of an ellipsoid whose heat capacity is optimized to the needs.
• a method of making an electrode by laser uses the following steps:
• the sphering is similar to that described in principle in DE-A 42 03 975.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Discharge Lamp (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=40433412

Family Applications (1)

Country Status (6)

Families Citing this family (2)

Family Cites Families (15)

• 2007
  • 2007-12-20 DE DE102007061514A patent/DE102007061514A1/de not_active Withdrawn
• 2008
  • 2008-11-18 WO PCT/EP2008/065742 patent/WO2009080412A1/de active Application Filing
  • 2008-11-18 JP JP2010538527A patent/JP2011507200A/ja active Pending
  • 2008-11-18 CN CN2008801220904A patent/CN101903972A/zh active Pending
  • 2008-11-18 US US12/809,074 patent/US20100308723A1/en not_active Abandoned
  • 2008-11-18 EP EP08865271A patent/EP2223331A1/de not_active Withdrawn

Non-Patent Citations (1)

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