IEE  Workshop    

STEVE  DENBAARS,  JAMES  RARING,  PAUL  RUDY,  SHUJI  NAKAMURA  SORAA  LASER  485  PINE  AVE  

GOLETA,  CA  93117  

Laser  Diodes  for  Energy  Efficient  Light  Sources  

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“Laser diodes are lighting's future.”

-  Professor Shuji Nakamura, 2014 Nobel Prize in Physics,r

LuxReview, Nov 5, 2014

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INTRODUCTION TO SORAA LASER

History  •  SLD  spun  out  of  Soraa  in  2013  •  ~40  employees  including  GaN  pioneers  UCSB  Prof  

Nakamura,  Denbaars,  Speck,  Dr  James  raring,  Paul  Rudy  

 

 

 

 

Opera-ons  •  HQ  and  Epi  in  Goleta,  CA  (Santa  Barbara)  •  Device  engineering  &  fab  in  Fremont,  CA    

 

 

 

Technology  •  Next  gen  LDs  based  on  Semipolar  GaN  •  Rights  to  390  patents  and  applica_ons    

Displays  

Semipolar  Laser  Diode  Light  Source  

Illumina-on  

OUTLINE AND KEY MESSAGES

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•  LDs  are  solu_on  to  droop  with  10-­‐20X  more  power  per  chip  and  10,000X  the  spa_al  brightness  of  power  LEDs  

•  LD  +  phosphor  already  superior  for  direc_onal  applica_ons  

 

•  LDs  must  overcome  challenges  such  as  wall  plug  efficiency  to  achieve  maximum  adop_on  in  ligh_ng  

•  GaAs  LD  evolu_on  a  proven  pathway  for  GaN  LDs  to  follow  

•  LD  Light  Sources  Energy  Efficient  >80  lm/Waf  

0  –  1k  lumens  

1k  –  10k  lumens  

>  5k  lumens  

Laser  Displays  &  Ligh_ng  Segments  

Displays Cinema Business Education Home theater/TV Micro accessories Embedded pico Wearables

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Specialty lighting Entertainment Projection lighting Automotive Spotlight-flashlights

Laser  Diode  based  Ligh_ng  

True  point  source  light    

Extremely  high  luminous  emifance    Highly  direc_onal  emission    

Higher  Current  Density    

10-­‐100  A/cm2    for  LEDs  1-­‐10  kA/cm2  for  LDs  

 Reduced  substrate  use    

1/10th  the  size  of  standard  LED  1/100th  the  size  of  a  power  chip  

Source:BW  MotorTrend  

LD + PHOSPHOR FOR ILLUMINATION

•  Low  etendue  +  high  brightness  make  LDs  ideal  excita-on  source    

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LD  +  Phosphor  <100um  Ø  spot  on  phosphor  

3W  LD  à >380  W/mm2    

LDs  300  -­‐1,000X  brighter  than  LED:  Superior  for  direc-onal  ligh-ng  Even  with  ½  the  WPE,  LDs  can  provide  higher  delivered  lm/W      

LD + PHOSPHOR CONFIGURATIONS

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•  Phosphor  technology  for  high  power  density  LD  excita_on  exists  today    •  Ceramic  and  single-­‐crystal  YAG:CE  demonstrate  low  thermal  quenching,  high  IQE,  

and  robust  life-mes  at  >200C  with  3W  LD  spots  <100um  

•  Infinite  number  of  LD  +  phosphor  configura_ons;    Opportunity    

Transmission   Reflec-on   Remote:  T  or  R  e.g.  spotlights,  headlights,  direc-onal  bulbs,  etc    

e.g.  spotlights,  headlights,  direc-onal  bulbs,  etc    

e.g.  street,  bridge,  tunnel  light;  integrated  bldg  materials  

Laser  Light  for  Auto  Ligh_ng  

VISIBILITY RANGE: LASER HIGH BEAM, LED HIGH BEAM, LOW BEAM

700M

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Laser Light Source: Increase Safety at Night

700 meter range!

LPPs  headlight  size  reduc_on,  Valeo  

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“Very  thin  headlamp  with    laser  sources”        Valeo  Ligh_ng  Systems  ISAL  2013  

10mm target Laser Light

Automo_ve  ligh_ng  market  is  >$15B/yr  

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“The automotive lighting market is growing steadily. The 2011 market size was estimated at EUR 14 billion, representing approximately 20 percent of the total market. This is expected to climb to EUR 18 billion by 2020.”

From: “Lighting the way, Perspectives on the Global Lighting Market” McKinsey & Company, Dec, 2012

EXTERNAL QUANTUM EFFICIENCY

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Narukawa  et  al,  J.  Phys.  D:  Appl.  Phys.  43  (2010)  354002    

LDs  are  droop  free  at  100X  the  current  density  of  LEDs  

Pulsed  data  

LED VS LD: POWER PER CHIP AREA

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Current  LDs  produce  10-­‐20X  more  light  per  chip  area  

Pulsed  data  

4.5W  

1.8W  

Narukawa  et  al,  J.  Phys.  D:  Appl.  Phys.  43  (2010)  354002    

SORAA    LASER  DIODE  Recent  high  power  performance  demo  

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•  On  track  to  achieve  >3W/35%  with  near-­‐term  process  improvements    

•  In  the  long  term,  >5W/50%  will  be  achieved  with  a  wider  stripe  and  device  op_miza_on  

>4  W  CW  at  25  C  at  445nm,  15  um  stripe  width  

Enables  >800  lumen  sources,  100  lm/W  

•  Polariza_on  causes  electron/hole  separa_on  •  Separa_on  reduces  radia_ve  recombina_on  efficiency  •  Isotropic  strain  does  not  improve  gain  

•  Eliminates  spa_al  separa_on  of  electron  and  hole    •  High  radia_ve  recombina_on  rate  for  increased  gain  •  Anisotropic  strain  for  reduced  hole  mass    •  3x  –  5x  increased  gain  for  shorter  devices  &  low  Ith  

Nichia/Osram  Technology:  C-­‐plane   SLD  Technology:    Semipolar  

Semipolar  is  Superior  to  C-­‐plane  

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LED VS LD: OUTPUT POWER DENSITY

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LD  aperture  10,000X  brighter  than  LED  emider  

Pulsed  data  

Narukawa  et  al,  J.  Phys.  D:  Appl.  Phys.  43  (2010)  354002    

Technical  Areas  of  Protec_on  

Apps  

Module  

Device  

Process/Epitaxy  

•  Laser Display and Illumination

•  Laser Module Plus Phosphor

•  Earliest Semipolar Technology –  Blue Laser –  Green Laser

•  Laser epi and fab processes –  Epitaxy structures and processes –  Gen2 and Gen3 fabrication

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SORAA    LASER  DIODE  

SLD  owns  rights  to  390  U.S.  and  foreign  patents  and  applica-ons  •  Third  Party  Freedom-­‐to-­‐Operate  for  laser  diode  products  •  Blocking  patent  rights  in  semi-­‐polar  orienta_on  •  Includes  11  licensed  patents/apps  from  UCSB;  Earliest  semi-­‐polar  •  Includes  6  earliest  Gen3  LD  U.S.  applica_ons  and  3  foreign  applica_ons    

CATEGORYISSUED/

ALLOWED(U.S.)

PENDING (U.S.) PENDING (FOREIGN)

SLD OWNED 37 33 19

SLD LICENSED 76 121 84

TOTALS 113 154 123

IP – Uniquely Strong Patent Position

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SUMMARY: LDS HAVE BRIGHT FUTURE LDs  offer  inherent  benefits  over  LEDs;  Next  Gen  light  sources  •  LDs  are  Droop-­‐Free  at  >100x  current  density  •  LDs  are  10,000x  brighter  and  can  yield  10-­‐20x  more  power  from  epi  wafer  

•  LD  sources  already  provide  superior  “delivered  lm/W”  in  direc_onal  apps  

LD  adop-on  will  grow  with  tech  maturity  and  Next  Gen  ligh-ng  •  GaAs  LDs  paved  a  proven  pathway  towards  performance  and  cost  for  GaN  LDs  

•  SHEDs  as  example  of  a  program  to  drive  GaN  LDs  to  GaN  LED  efficiencies  

•  Benefits  of  LDs  will  become  further  cri_cal  in  Next  Gen  ligh_ng  

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