Photonic Technologies for LiDAR in Autonomous/ADAS. Jake Li (Market Specialist SiPM & Automotive) Hamamatsu Corporation

Transcription

1 Photonic Technologies for LiDAR in Autonomous/ADAS Jake Li (Market Specialist SiPM & Automotive) Hamamatsu Corporation

2 Outline of Presentation 1. Introduction to Hamamatsu 2. Autonomous Levels and Technologies 3. LiDAR Systems Comparison 4. Photonic Components Comparison 5. Summary 2

3 Intro to Hamamatsu 3

4 Hamamatsu Company Background Established: September 29, 1953 Employees: 4,415 Annual Revenue > $1 Billion Global Leader in Photonic components U.S. Office locations Boston San Jose US HQ New Jersey San Diego Chicago 4

5 Hamamatsu Focused Markets and Applications 4% Automotive Sensors 5

6 Hamamatsu Sales by Automotive Application 3% 13% 5% 12% 18% 49% MOST Network Sun Sensor LiDAR Headlight Control Anti-Glare Mirror Others Other Quality Standards (Important to Automotive): 1. IATF16949(2016), previously TS16949(2009) 2. AEC-Q100 & AEC-Q ISO

7 Autonomous Levels and Technologies 7

8 Autonomous and ADAS Overview (Today) Limited Automation Level 0 Level 1 Level 2 No automation Driver has complete control Driver assistance Default level of automation for most new cars today Limited automation Limited availability on some new vehicles today Ultrasonic Radar LiDAR Camera 8

9 Autonomous and ADAS Overview (Future) Technologies Still Being Developed (Semi to Full Automation) Level 3 Level 4 Level 5 Conditional automation Driver is expected to intervene and take over the control at any time High automation Driver can take over the control but not required Full automation No driver interaction necessary Sensor Fusion Functional Safety Ultrasonic Sensors Camera GPS 3D Sensors Radar LiDAR 9

10 Current Autonomous System Technology Comparisons Performance Compared Under Specific Conditions Camera RADAR LiDAR Dark, Little to No Light Variable Lighting Condition Will Not Work Blinds the Camera Very Good (Technology Not Effected by Light Conditions) Very Good (Technology Not Effected by Light Conditions) Very Good Very Good Adverse Weather (Rain, Snow and Fog) Shortens Range Very Good Shortens Range Angular Resolution Poor at Long Range Currently (2-5 Deg) Developmental (0.5-1 Deg) 0.1 Degree Color & Contrast Yes No No Color, Limited Contrast Info Cost of Today Technology 2 Mega Pixel Resolution (Low Cost, <$5 to $10) 24 GHZ RADAR (Medium Cost, < $50) Higher Frequency Radar Commercialized LIDAR System (Higher Cost)

11 Angular Resolution Long Range Short Range For high-resolution 3D map, we need LiDAR, especially for long range 11

12 Future Sensor Ideal Improvements and Limitations Performance Compared Under Specific Conditions Camera RADAR LiDAR Dark, Little to No Light IR/NIR Camera or Active Will Not Light Work Source Very Good (Technology Not Effected by Light Conditions) Very Good Variable Lighting Condition High Dynamic Range Blinds the Camera Camera Very Good (Technology Not Effected by Light Conditions) Very Good Adverse Weather (Rain, Snow and Fog) New Shortens Image Range Sensor Technology Very Good New Detector Technology & ASIC & Shortens Range Algorithm Improvement Angular Resolution Higher Resolution Poor at Long Range Camera Currently Increase (2-5 in size Deg) + Developmental more antennas ( higher Deg) frequency 0.1 Degree Future Cost Assessment 2 Mega Pixel Resolution (Low Cost, <$5 to $10) 24 GHZ RADAR (Medium Cost, < $50) Cost Should Decrease Commercialized Gradually LIDAR System (realistic cost vs. performance (Higher Cost) need 12 to be considered)

13 LiDAR Systems Comparison 13

14 Type of LiDAR Systems Mechanical LiDAR 14

15 Type of LiDAR Systems Mechanical LiDAR Advantages: 1. Best performance & resolution 2. Longest range 3. One system for 360 degrees Limitations: 1. Bulky design with moving parts 2. Higher cost 3. Protruding design Future of this technology: Great for fleet vehicles, robotics, BUT not ideal for consumer vehicles Potential risk of being replaced by a solid state LiDAR concept 15

16 Type of LiDAR Systems Rotating Multi-Facet Mirror 16

17 Type of LiDAR Systems Rotating Multi-Facet Mirror Advantages: 1. Proven design that s commercialized 2. Low cost design Limitations: 1. Lower performance Resolution Field of view 2. High development cost to meet 3D LiDAR system requirements Future of this technology: Great for low performance ADAS systems May not meet requirements of 3D high resolution LiDAR system for Level 3 and higher vehicles Likely replaced by solid state LiDAR designs in the future 17

18 Type of LiDAR Systems Flash LiDAR 18

19 Type of LiDAR Systems Flash LiDAR Advantages: 1. Solid state technology - no moving parts 2. Compact and light weight 3. Low cost option for short range Limitations: 1. Limited range with technology today 2. Field of view vs. cost of components Image source: Continental Corporation Future of this technology: Improvement of technology needed to improve range photon counting detectors, higher power VCSELs, & 1550nm? Cost of the system need to be realistic vs. performance requirements 19

20 Type of LiDAR Systems Beam Steering Via MEMs Mirror 2D Mirror Scanning Method Photo Detector timing circuit Light projector, with 2D MEMS mirrors Light source Photo Detector Array 1D Mirror Hybrid Flash Method timing circuit Light projector, with 1D MEMS mirrors Light source 20

21 Type of LiDAR Systems Beam Steering Via MEMs Mirror 1D 2D 21

22 MEMs Mirror Technology Comparisons 22

23 Type of LiDAR Systems Beam Steering Via MEMs Mirror Advantages: 1. Good performance, range, resolution 2. MEMs technology proven for automotive 3. Low cost high resolution LiDAR concept for mid to long range 4. Compact and lightweight Limitations: 1. Consider shock and vibration 2. Consider ISO Consider MEMs Mirror design compromises Image source: 1D Mirror Based Flash LiDAR (LeddarTech) Future of this technology: Ideal higher resolution LiDAR concept in the near future with best balance of cost vs. performance Once tested and qualified, concept is viable for all markets Cost of the system need to be realistic vs. performance requirements 23

24 LiDAR Systems Beam Steering (Optical Phased Array) Advantages: 1. True solid state design - no moving parts 2. Compact and light weight optical antennas Limitations: 1. Light loss that may restrict range 2. Heat dissipation to be considered Future of this technology: Excellent design for short to mid range Good fit for fleet vehicles and industrial related applications Cost of the system need to be realistic vs. performance requirements 24

25 LiDAR Systems Frequency-Modulated Continuous-Wave Chirp-modulation (triangular) of frequency f 0 f max f 0 f B max frequency t = 0 t = T t = 2T t = 3T time F d = Frequency Difference (Beat Frequency) Δt = Time Delay 25

26 LiDAR Systems Frequency-Modulated Continuous-Wave Advantages: 1. One return signal contain velocity and distance info 2. Ambient noise not an issue 3. High gain photodetector not required due to heterodyne optical mixing technique that provides optical gain Limitations: 1. Still need beam steering technology 2. Powerful processor needed for information processing Future of this technology: 1D and low resolution concept already works High resolution concept to be demonstrated Cost of the system need to be realistic vs. performance requirements 26

27 Is there a perfect LiDAR? LiDAR System Range Reliability Cost Size Systems per car Mechanical Long Good Mid. to high Bulky 1 MEMS based Medium to long Good Low Compact 1 4 or more Flash Short Very good Low Compact 1 4 or more Optical Phase Array FMCW Advantages: solid state design with no moving parts Disadvantages: loss of light that restricts the range Advantages: immune to background, photon shot noise detection Disadvantages: data processing intensive, still requires beam steering Not yet 27

28 Photonic Components Comparison 28

29 Photonics Components for LiDAR Light Source Considerations Image source: Philips VCSELs VCSELs Flash LiDAR, Edge-emitting Scanning LiDAR Limited power at 905 nm, common option & lower cost For 1550 nm, limited offering and higher cost High customization requirements 29

30 Photonics Components for LiDAR Photodetector Considerations Silicon or InGaAs per eye safety limitations Silicon for UV to NIR (190 nm to 1100 nm), for 905 nm to 1100 nm InGaAs for VIS to IR (0.9 um to 2.6 um), higher cost option, for 1550 nm Detector gain and NIR sensitivity range of detection Wide dynamic range Distant black target has very weak reflected light Nearby shiny target reflects too much light Array capability Customization capability Many other requirements maybe considered!! 30

31 Photonics Technology for LiDAR Photodetectors No Gain Fast and low cost Silicon or InGaAs depends on range requirement No internal gain ideal for short to medium range Low noise electronics required higher system cost 31

32 Photonics Technology for LiDAR Photodetectors X 10 2 Some internal gain (100X) for better range Silicon for short to medium range InGaAs for short to long range Low noise electronics required higher system cost Consider temperature sensitivity and high bias voltage 32

33 Photonics Technology for LiDAR Photodetectors High internal gain (10 6 ) and high NIR sensitivity (7%) for high range Silicon only for medium to long range Low cost electronics low system cost Consider temperature sensitivity and bias voltage 33

34 Photonics Technology for LiDAR SiPM Improvements Current SiPM technology has limited sensitivity at 905 nm Higher NIR sensitivity SiPM may replace InGaAs APDs for long range 905nm 7% 34

35 LiDAR Technology Comparisons Photodetectors SiPMs APD PIN Photodiode Hybrid Device (APD/Photodiode + TIA) Gain 10 6 <100 None <100 Range Mid to Long Mid to Long Short Short to Long Readout Circuit Simple Complex Complex Simple Cost Low System Cost (Medium Detector Cost) High System Cost (High Detector Cost) High System Cost (Low Detector Cost) Low System Cost (High Detector Cost) Design Complexity Temperature compensation Signal integrity & temperature compensation Signal integrity Complex, signal integrity or temperature compensation Spectral Range Up to 950 nm Up to 1150 nm (Silicon) Up to 1700 nm (InGaAs) Up to 1200 nm (Silicon) Up to 2.6 um (InGaAs) Up to 1050 nm (Silicon) Up to 1600 nm (InGaAs) Speed Medium, limited by recovery time Fast Fast Slow, limited by TIA Operating Voltage < 80 V < 200 V < 10 V 120 to 200 V Dark Output/Noise High Detector Noise (Low System Noise) Low Detector Noise (High System Noise Limited by amplifier) Low Detector Noise (High System Noise Limited by amplifier) Low Detector and System Noise 35

36 Summary There s not one perfect technology!! One source supplier and unbiased opinions from Hamamatsu: Photodetectors Photodiodes, APDs, SiPMs, Hybrid Detectors, SPAD and Others Light Sources MEMs Mirrors, Laser Diodes and LED, Pulsed or CW Supporting Electronics/Assemblies/Modules & various optics options available High customization requirements and needs in the market LiDAR is critical to sensor fusion, component supplier has to be capable in manufacturing high volume quality, reliable and repeatable products Full control of manufacturing and design processes Ability to quickly ramp up and support high volume production Experience with various automotive related standards: IATF 16949(2016), AEC-Q100/Q102, and ISO

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