High Power VCSEL Systems For Thermal Processing

Transcription

1 High Power VCSEL Systems For Thermal Processing Günther Derra Philips Photonics 1 Philips Photonics presented at LASYS Lasers in Action Forum

2 Digital Heating : Get the Heat Where Needed Many industrial processes require heating, but are wasting energy Not spatially selective Broad spectral distribution Slow switching, poor control Directed power on target only Single wavelength Precise & fast control VCSEL Systems are the smart laser solution for large-area thermal processing! 2 Philips Photonics presented at LASYS Lasers in Action Forum

3 VCSEL: Vertical Cavity Surface Emitting Laser-Diode VCSEL arrays: thousands of micro-lasers on a chip On-wafer testing and chip selection LED-like assembly Robust against back reflection Standard wavelength 980 nm 3 Philips Photonics presented at LASYS Lasers in Action Forum

4 Philips Photonics: Leader in VCSEL Technology Core Value: VCSEL components Business segment Components for Data communication & sensing Ulm Location VCSEL production facility Ulm Currently shipping 10M VCSELs per month, expecting doubling in 2016 Sensors and illumination modules High power systems for heating Eindhoven Aachen 4 Philips Photonics presented at LASYS Lasers in Action Forum

5 Optical Interconnects - 10x Bandwidth, 10x Less Power Exponential Growth of Data Traffic Active optical cables Electrical interface Transmitter / receiver in plug Google data center Direct silicon-to-optics interconnect: soon 5 Tb/s 1 mm Photo diodes 4x 25Gbps Laser diodes 12x14 VCSEL array 5 Philips Photonics presented at LASYS Lasers in Action Forum

6 VCSEL Sensing Everywhere Soon 5-10 VCSEL in every Smart Phone Illumination for Cameras Gesture Control Body function Proximity sensing High speed display connect HDMI interconnect Auto focus camera Environmental sensors Night vision camera Multiple Watts of VCSEL in every car high precision industrial sensors 6 Philips Photonics presented at LASYS Lasers in Action Forum

7 High Power Lasers from Simple Building Blocks Single VCSELs VCSEL array Assembled chip Chips in series 30 µm 200 µm 2 mm 1-10 mw/vcsel 1-2 W/mm² 2200 VCSELs/chip 2 mm 7 W/chip VCSEL Emitter 400 W/emitter High power modules 2 50 kw/module 20 mm 7 Philips Photonics presented at LASYS Lasers in Action Forum

8 Scalable Module Design Direct treatment of large areas 100 W/cm² power density at emission aperture Standard wavelengths 980 or 808 nm Compact Easy to integrate 4.8 kw module emission area 104 x 40 mm² kw module emission area 209 x 40 mm² Philips Photonics presented at LASYS Lasers in Action Forum

9 VCSEL Heating Patterns Large Systems: Simulated intensity distribution as a function of emitter target distance Intmax:= 80 W IP1 0 0 := Intmax IP2 0 0 := Intmax IP3 0 0 := Intmax IP4 0 0 := Intmax IP5 0 0 := Intmax IP6 0 0 := Intmax cm 2 offx = 0 mm 0= 0 deg dist T = ( ) mm window size: xx= 100 yy mm= 240 mm 30 mm 50 mm 70 mm 100 mm 150 mm 200 mm image size 240 x 100 mm² WD = 200mm 280mm, yyv, dist IV 0 x - ivx dvx xxv y ivy dvy ( ) xx yy -, ipy dpy -, 100mm % 80% rel. intensity 0 IPipx, ipy := IV ipx dpx ( ) 5 x 19 kw (400 mm) 9 Philips Photonics presented at LASYS Lasers in Action Forum image size 500 x 500 mm² := IV ( x, y, dist ) ivx ivy

10 x y, dist, ( ) IV := ivx ivy ipy, IV ipx dpx IPipx, ( ) 0 x ivx dvx xxv + y ivy dvy IV := 2 ipy dpy - xx 0.5 yyv +, dist - 2 -, 100mm yy, Large Area Processing: Simulations for 12 Wafer Linear configuration of Standard modules: 168 Emitters 67.2 kw 52 W/cm² = 67.2 kw working I = 10.65distances: A P mod wd T = 67.2 = ( 10 kw working 400 distances: ) wd mm T = ( ) mm 100% 80% rel. intensity 0 WD = 20 mm 350 mm 450 mm image size 400 x 400 mm² W SX = 400 mm SY = 400 mm rows( RE) = 336 Imax = ( ) cm 2 I I= = AA PP = wd T mod = 44.8 kw working distances: wd T = = ( 10 ( ) ) mm Potential Brick configuration: 112 Emitters 44.8 kw - 42 W/cm² WD = 20 mm 200 mm 300 mm I = A P mod = 44.8 kw working distances: wd T = ( mm rows( RESX ) = = mmimax SY= ( mm 70.8 rows61.29 ( RE) = W Imax = ( ) ) W cm 2 cm 2 image size 400 x 400 mm² 10 SX = 400 mm Philips Photonics presented at LASYS Lasers in Action Forum SY = 400 mm rows( RE) = 224 Imax = (

11 Unique Feature: Flexible Control of Laser Zones Narrow laser zones controlled independently: Flexible control of the heating profile Fast switching & setting of heating power (milliseconds) Closed-loop control possible Current: VCSELs: Heating zones enabling control of thermal profile IR power: Target: Structured thermal processing: 11 Philips Photonics presented at LASYS Lasers in Action Forum

12 Flexible Control of Heating Profile Example measurements of intensity distribution with 9.6 kw VCSEL-System Emission area: 209 x 40 mm² Measurement of intensity pattern Heating of a thin plate Initial temperature rise (< 1s) is a good measure of incident power density Thermal map representing incident IR distribution VCSEL module thin screen IR camera 12 Philips Photonics presented at LASYS Lasers in Action Forum

13 Structured Heating Example IR camera image with VCSEL module at top Moving plastic sheet heated by structured laser treatment Variation of heating pattern in time Below: temperature profile 13 Philips Photonics presented at LASYS Lasers in Action Forum

14 Layout of a Typical VCSEL Heating System VCSEL heating module Air knife inlets Purge gas Water cooling unit Driver unit Primary cooling water Communication interface Safety interlock 14 Philips Photonics presented at LASYS Lasers in Action Forum

15 VCSEL Advantages for Heat Treatment Advantages over conventional heating: High process speed energy density 100 W/cm² Heat only when needed by fast switching Heat only where needed by directed beam and tailored heating profiles Narrow spectrum stable at all power levels High lifetime 30 khrs expected Conventional VCSEL Advantage over conventional diode lasers: Area treatment by design instead of odd-shaped beam no expensive bulky optics or scanner systems Lower cost by factor of 2-5 compared to standard diode laser systems Machine-ready compact, easy to integrate, robust, safe against back reflection 15 Philips Photonics presented at LASYS Lasers in Action Forum

16 Local Heating of Steel VCSELs can heat large target areas simultaneously 10 s to reach 900 C at 1.50 mm steel thickness with 100 W/cm² 2 s to reach 600 C at 0.25 mm steel thickness with 50 W/cm² 50 W/cm², model assuming 55% absorption Selective softening of high-strength steel 16 Philips Photonics presented at LASYS Lasers in Action Forum

17 Metallization Line Sintering In Solar Cell Production Successful VCSEL system integration in a commercial Fast Firing Line of Rehm Thermal Systems Test wafers were processed at Rehm and characterized by Fraunhofer ISE Exerimental results: Ultrafast temperature rise in 4 cm treatment length Benchmark cell efficiency reached New compact machine concepts may become feasible 1050 K/s 17 Philips Photonics presented at LASYS Lasers in Action Forum

18 Solar Cell Treatment Example for heat treatment up to 1000 C 18 Philips Photonics presented at LASYS Lasers in Action Forum

19 Plastics Welding Test conditions: Standard VCSEL Module with 1.6kW IR power (980nm) Pressurized sample holder Samples: PP and PBT courtesy of Lap Joint Localized heating zone transparent Simultaneous welding with 1s treatment time absorbent Large area welding of PBT Test pattern for microfluidic application 19 Philips Photonics presented at LASYS Lasers in Action Forum

20 Foam Welding Test conditions: Standard VCSEL Module with 1.6kW IR power (980nm) Tests stationary and with linear motion Results: very good joining quality possible Black foam without absorber foil Colored or white foam with absorber layer glass plate holder laser beam white foam absorber colored foam Perfect connection Welding examples: black foam without absorber foil colored foam with absorber foil 20 Philips Photonics presented at LASYS Lasers in Action Forum

21 Carbon Fiber Placement VCSEL modules integrated on the tape-laying head 100W/cm² power density enabling high speed process Controllable spatial heating profile Controllable dynamic heating profile Closed-loop control possible Courtesy Fraunhofer IPT Courtesy Fraunhofer IPT 1.6kW compact VCSEL module integrated into tape-laying equipment 21 Philips Photonics presented at LASYS Lasers in Action Forum

22 Carbon Fiber Placement Test setup at Fraunhofer IPT Consolidation roller Tape Substrate VCSEL module Ring 22 Philips Photonics presented at LASYS Lasers in Action Forum

23 Compact Module Concept for Fiber Placement Compact triangular form Water cooling connection to module sides Electrical connections adaptable to requirements Example module 9.6 kw IR 24 VCSEL emitters emission area 209 x 40 mm² Potential configurations for fiber placement: 23 Philips Photonics presented at LASYS Lasers in Action Forum

24 Application Example: Laser Edging of Furniture Panels High-quality solution for joining edge bands to wooden furniture panels Plastics welding process yielding best edge quality Tight seal by laser heating of special edge band Requirements: high process speed > 15 m/min direct heating with good uniformity fast reconfiguration to material type and size fast switching, precise power control harsh environmental conditions Roller Panel VCSEL Module Very limited volume available for laser module Redesign of the standard laser housing? 24 Philips Photonics presented at LASYS Lasers in Action Forum

25 Seamless Laser Edging of Furniture Panels IMALUX High power VCSEL system is integrated in professional woodworking machines (IMA Klessmann GmbH) Fast development time of the VCSEL module within 3 months Uniform direct heating, no optics Electronic control of heating zones Robust system operated in harsh environment Much lower cost than existing laser solutions 25 Philips Photonics presented at LASYS Lasers in Action Forum

26 Conclusions High power VCSEL systems are offering attractive solutions for industrial thermal processes High power density, enabling fast processing Precisely controllable, in time and spatially Scalable to any power level Compact, robust and easy to integrate Lower cost than conventional laser systems Potential application fields Plastics welding & forming Composite manufacturing Coatings, curing,... Photovoltaics Sheet & coil treatment...? 26 Philips Photonics presented at LASYS Lasers in Action Forum

27 27 Philips Photonics presented at LASYS Lasers in Action Forum