Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
  • H01S3/02—Constructional details
  • H01S3/04—Arrangements for thermal management
  • H01S3/0407—Liquid cooling, e.g. by water
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L23/00—Details of semiconductor or other solid state devices
  • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
  • H01L23/46—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements involving the transfer of heat by flowing fluids
  • H01L23/473—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements involving the transfer of heat by flowing fluids by flowing liquids
  • H01L23/4735—Jet impingement
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
  • H01S3/02—Constructional details
  • H01S3/04—Arrangements for thermal management
  • H01S3/0405—Conductive cooling, e.g. by heat sinks or thermo-electric elements
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
  • H01S3/02—Constructional details
  • H01S3/04—Arrangements for thermal management
  • H01S3/042—Arrangements for thermal management for solid state lasers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
  • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
  • H01S3/06—Construction or shape of active medium
  • H01S3/0602—Crystal lasers or glass lasers
  • H01S3/0604—Crystal lasers or glass lasers in the form of a plate or disc

Definitions

• the invention relates to an impingement cooling device for a laser disk, with a particular disc-shaped support plate, on the front side of the laser disc can be fastened, with a support structure, on the front side, the back of the support plate is fixed, and with an impingement cooling for cooling the support plate by means of a cooling liquid wherein the support structure comprises a plurality of cooling liquid supply lines, from which the cooling liquid in the direction of the back of the support plate, in particular perpendicular to the back of the support plate exits, and a plurality of cooling liquid return lines, as well as a laser disk module with such a baffle cooling device.
• Such an impingement cooling device has become known, for example, from US 2014/0 190 665 A1.
• laser discs are glued to disc-shaped heat sinks (disc carrier) made of CVD diamond, which are cooled on the back by impingement flow.
• the thermomechanical properties of the wafer carrier now determine the thermal lensing effect of the laser disk.
• the impact cooling device disclosed in the aforementioned US 2014/060 665 A1 has a single recess adjacent to the rear side of the carrier plate and radially extending return lines.
• a laser disk is mounted on a carrier plate which simultaneously forms a resonator mirror of a laser resonator.
• a cooling liquid emerging from a nozzle opening impinges against the self-supporting rear side of the carrier plate, which is cooled thereby.
• US Pat. No. 6,339,605 B1 discloses cooling for a laser disk mounted on a copper substrate.
• the copper substrate is traversed by a cooling liquid, which is passed into microchannels of the copper substrate, which are open to the laser disk.
• the back of the laser disk is thus cooled by the coolant flowing through the microchannels.
• US 2007/0297469 A1 discloses a cooling system for a laser disk, which is mounted on a support plate made of diamond or sapphire. Within the carrier plate, near-surface microchannels extend for a cooling liquid.
• the present invention is based on the object, in an impingement cooling device of the type mentioned to achieve a higher stiffness of the support plate with almost the same thermal resistance of the support plate, without having to increase the thickness of the (diamond) support plate.
• a backing plate e.g., diamond material
• a stiffening back support structure e.g., tungsten carbide or aluminum nitride
• the recesses of the support structure may be open either to the back of the support plate, so that the cooling liquid directly against the back of the Support plate bounces (direct heat transfer of the support plate in the cooling liquid), or be closed to the back of the support plate out, so that the cooling liquid bounces against a bottom of the support plate. In the latter case, the direct contact between the cooling liquid and a solder located between the support plate and the support structure is avoided, thereby reducing the risk of corrosion.
• the backing plate is formed of diamond material (e.g., CVD diamond or polycrystalline diamond composite (PDC)) and more particularly has a thickness of at most 5mm, preferably at most 3mm, more preferably at most 2mm.
• the diamond material offers high thermal conductivity and at the same time enough inherent rigidity to prevent the shape of the front-mounted laser disk from being significantly affected by the backside cooling structures.
• the carrier plate and the support structure are soldered, glued, sintered or connected to one another by so-called bonding, ie by a mechanically strong, rigid connection between two solids without the formation of an intermediate layer.
• the back of the carrier plate is fixed to the front of a distributor plate having the recesses, the back of the distributor plate being attached to a support body having the supply and return lines.
• the support body is formed of ceramic or hard metal and in particular has a thickness of at least 1 cm, preferably between 2cm and 10cm on.
• the recesses extend as passage openings to the rear of the distributor plate.
• the distributor plate may also have upstream of its recesses nozzle openings, which are aligned in the direction of the back of the carrier plate, in particular at right angles to the back of the carrier plate.
• the distributor plate may be formed either from diamond material or, as is preferred, from ceramic or hard metal (eg tungsten carbide or aluminum nitride) and in particular have a thickness of at least 0.3 mm, preferably at least 0.5 mm.
• the recesses of the distributor plate may be open towards the rear side of the carrier plate, in particular extending as passage openings from the front side to the rear side of the distributor plate, so that the cooling fluid impacts against the rear side of the carrier plate, or be closed by a bottom of the distributor plate, so that the coolant splashes against the bottom of the distributor plate.
• a nozzle plate with nozzle openings which connect the leads of the support body respectively with the recesses of the distributor plate and in the direction of the back of the support plate, in particular at right angles to the back of the support plate, aligned, and with through holes, which connect the recesses of the distributor plate with the return lines arranged.
• the nozzle plate is formed of diamond material (e.g., CVD or PDC diamond), ceramic or cemented carbide (e.g., tungsten carbide or aluminum nitride), and more preferably has a thickness of at least 0.3mm, preferably at least 0.5mm.
• the individual components of the support structure are soldered to one another depending on the material pairing, e.g. by brazing on copper and / or silver, or glued, sintered or gebonded.
• the rear side of the carrier plate has the recesses and is fastened to the front side of a support body which has the feed lines and return lines.
• a carrier plate made of CVD diamond can be provided, for example, by laser processing on the back with the recesses for impinging the impact flow and then a shaft made of, for example, tungsten carbide with brazing solder on the structured back. Subsequently, the required supply and return lines can be introduced by spark erosion in the tungsten carbide.
• the support body can also be composed of individual laser-cut perforated disks, which are soldered together to form a stack and whose soldering rather aligned with each other to form in the stack through feed and return lines.
• the support body is preferably formed of ceramic or cemented carbide (e.g., tungsten carbide or aluminum nitride) and has a thickness of at least 0.5cm, preferably between 0.5cm and 10cm, in order to sufficiently increase the rigidity of the support plate.
• ceramic or cemented carbide e.g., tungsten carbide or aluminum nitride
• the supply and return lines are formed in the support body through passageways which are introduced side by side into the support body, e.g. are bored.
• the supply lines in the support body each formed by a separate tube (for example, nozzle needle), which is arranged to form a (ring) gap in a passageway of the support body.
• the return lines in the support body are each formed by the existing between the passageway and pipe (ring) gap.
• the supply line of only a single return line is ring-shaped or partially ring-shaped, resulting in the case of an annular return line in a homogeneous spatial cooling distribution.
• the return conduits may each be formed by a separate tube (e.g., nozzle needle) in a passageway of the support body and the inlets respectively through the passageway between the passageway and the tube
• each of the supply lines of several return lines in particular point-symmetrical to the supply line, surrounded, wherein the return lines in turn depart from that recess of the distributor plate, in which the feed line surrounded by them opens.
• each supply line is associated with a plurality of return lines, resulting in a homogeneous spatial cooling distribution.
• the supply and return lines run parallel to one another in the longitudinal direction of the support structure, ie in the case of a support body in its thickness direction.
• the invention also relates to a laser disk module having a baffle cooling device configured as above and having a laser disk which is fastened to the front side of the carrier plate of the baffle cooling device.
• FIGS. 1 a, 1 b show a first exemplary embodiment of the impingement cooling device according to the invention for a laser disk in the mounted state (FIG. 1 a) and in an exploded view (FIG. 1 b);
• FIG. 2 shows a schematic longitudinal section through the impingement cooling device of FIG. 1 in the region of a supply line arranged between two return lines;
• FIG. 3 shows a second embodiment of the impingement cooling device according to the invention in a schematic longitudinal section analogous to FIG. 2;
• FIG. 4 shows a third embodiment of the impingement cooling device according to the invention in a schematic longitudinal section analogous to FIG. 2;
• FIG. 5 shows a fourth exemplary embodiment of the impingement cooling device according to the invention in a schematic longitudinal section analogous to FIG. 2.
• baffle cooling device 1 is used for cooling a laser disk 2 of a disk laser (not shown) by means of a cooling liquid.
• the laser disk 2 is formed of laser active reinforcing material and may, for example, a Yb: YAG, Yb: LuAG, Yb: YAG, Yb: YLF, Yb: Lu 2 0 3 , Yb: LuAG, Yb: CALGO, Nd: YAG or Nd: YVO 4 crystal with a thickness of about 50 pm to about 500 ⁇ m.
• the impingement cooling device 1 comprises a disk-shaped support plate 3, on the front side 3a of which the laser disk 2 is fastened, and a rear support structure 4 on which the rear side 3b of the support plate 3 is fastened.
• the support structure 4 has a disk-shaped distributor plate 5, a disk-shaped nozzle plate 6 and a cylindrical support body (support block) 7 with a diameter of about 25- 40 mm.
• the rear side 3b of the carrier plate 3 is fixed to the front side 5a of the distributor plate 5, the rear side 5b of which is in turn secured to the front side 6a of the nozzle plate 6.
• the rear side 6b of the nozzle plate 6 is fixed to the front side 7a of the support body 7.
• the carrier plate 3 is made of a diamond material, e.g. CVD diamond or polycrystalline diamond composite (PDC), which has a high thermal conductivity and at the same time a sufficiently high inherent rigidity in order to avoid a significant influence on the shape of the mounted on the front side 3a laser disc 2 by backside cooling structures.
• the support plate 3 is only about 2-4mm thick.
• the distributor plate 5 has a plurality of recesses 8 which are open towards the rear side 3b of the carrier plate 3 as well as to the front side 6a of the nozzle plate 6, thus extending as through-openings from the front side 5a to the rear side 5b of the distributor plate 5.
• the distributor plate 5 may also be formed of a diamond material (e.g., CVD or PDC diamond) or alternatively ceramic or cemented carbide (e.g., tungsten carbide or aluminum nitride) to optimize cooling performance.
• a diamond material e.g., CVD or PDC diamond
• ceramic or cemented carbide e.g., tungsten carbide or aluminum nitride
• the distributor plate 5 is only approx.
• the nozzle plate 6 is formed of ceramic or hard metal and has a plurality of small nozzle openings 9 and a plurality of through channels 10, wherein each nozzle opening 9 is surrounded by a plurality of feedthrough channels 10.
• the nozzle openings 9 are each directed at right angles to the back of the support plate 3.
• the nozzle plate 6 is only about 0.5 mm thick.
• the support body 7 is formed of ceramic or hard metal (eg tungsten carbide or aluminum nitride) and has a plurality of cooling liquid supply lines and return lines 11, 12 formed as passage channels with a line diameter of 0.3-5 mm (preferably 3 mm) parallel extend to each other in the thickness direction of the support body 7.
• each supply line 1 1 is surrounded by several, here by way of example six return lines 12.
• Each feed line 1 1 opens via one of the nozzle openings 9 of the nozzle plate 6 in one of the recesses 8 of the distributor plate 5. From each recess 8 in turn go through the passage channels 10 of the nozzle plate 5 from those six return lines 12, which the opening into this recess 8 Surrounding supply line 1 1.
• the support body 7 is between 0.5cm to 10cm thick.
• soldering, bonding, sintering or bonding processes are provided, depending on the material pairing.
• a solder attention must be paid to compatibility between the solder and the cooling circuit with regard to corrosion.
• brazing alloys based on copper and / or silver are used.
• cooling liquid 13 flows into the impingement cooling device 1 via the supply line 1 1 of the support body 7 to the nozzle openings 9 of the nozzle plate 5 a. Since the opening cross-section of the nozzle opening 9 is smaller than the line cross-section of the supply line 1 1, the cooling liquid 13 exits the nozzle opening 9 accelerated in the recess 8 and bounces there against the back of the support plate 3 3b, which is thereby cooled.
• This impingement cooling is designated 14 in FIG.
• the bounced cooling liquid 13 then flows within the Recess 8 radially on the outside and on the through channels 10 of the nozzle plate 6 in the return lines 12 of the support body 7 a.
• the impingement cooling device 1 shown in FIG. 3 differs only in that here the recess 8 of the distributor plate 5 is closed towards the back 3b of the carrier plate 3 through a bottom 17 of the distributor plate 5.
• the cooling liquid 13 bounces against the bottom 17 of the distributor plate 3, so that the carrier plate 3 is not cooled directly by the cooling liquid 13, but indirectly via the bottom 17 of the distributor plate 3.
• the direct contact between the cooling liquid 13 and a solder located between the carrier plate 3 and distributor plate 3 is thereby avoided and the risk of corrosion is reduced.
• the impact cooling device 1 shown in FIG. 4 differs in that here the rear side 3b of the support plate 3 has the recess 8 'which is open toward the front side 7a of the support body 7 and is fastened directly to the front side 7a of the support body 7 is.
• the supply line 1 1 opens into the recess 8 of the support plate 3, from which in turn the return lines 12 depart.
• the cooling liquid 13 exits from the supply line 1 1 directly into the recess 8 and bounces there against the back 3b of the support plate 3, which is thereby cooled.
• the recess 8 ' is introduced, for example, by laser processing in the back 3b of the support plate 3.
• This structured back 3b of the support plate 3 is then soldered to the front side 7a of the support body 7 with brazing material.
• the required supply and return lines 1 1, 12 are introduced into the supporting body 7 by spark erosion.
• the support body 7 may be composed of individual laser cut perforated discs, which are soldered together in a stack and their holes are aligned with each other to form the continuous supply and return lines 1 1, 12 in the stack.
• the impingement cooling device 1 shown in Fig. 5 differs only in that here the supply line 1 1 in the support body 7 by a separate, free-standing pipe 14 (eg stainless steel) is formed in a passage 15 of the support body 7 below Forming an annular gap 16 is arranged, and in the support body 7 only a single return line 12 extends, which is formed by the present between the pipe 14 and passage 15 annular gap 16.
• the tube 14 extends with its one, free end up to the recess 8 'zoom in and is fixed at its other, fixed end to the back of the support body 7.
• the distributor plate 5 of FIG. 3 or the carrier plate 3 of FIG. 4 can be used.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• Optics & Photonics (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• General Physics & Mathematics (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Computer Hardware Design (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• Lasers (AREA)
• Semiconductor Lasers (AREA)
• Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)

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• 2016
  • 2016-04-05 DE DE102016205638.7A patent/DE102016205638B4/de active Active
• 2017
  • 2017-03-23 CN CN201780021959.5A patent/CN109075520A/zh active Pending
  • 2017-03-23 EP EP17713274.3A patent/EP3440748A1/de not_active Withdrawn
  • 2017-03-23 JP JP2018552237A patent/JP6835870B2/ja active Active
  • 2017-03-23 WO PCT/EP2017/056992 patent/WO2017174369A1/de active Application Filing
  • 2017-03-23 KR KR1020187031676A patent/KR102291295B1/ko active IP Right Grant
• 2018
  • 2018-10-01 US US16/148,269 patent/US10727639B2/en active Active
• 2020
  • 2020-07-22 US US16/935,373 patent/US11362475B2/en active Active

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