Find out how Short-wave Infrared camera technology can benefit machine vision and industrial applications including semiconductor inspection, photovoltaics, glass inspection and plastic sorting (hyperspectral imaging). This presentation also discusses the differences between SWIR and CCD/CMOS cameras.

1. Imaging beyond the visible An Overview of Short-Wave Infrared (SWIR) Technology for Machine Vision
Paul Maria Zalewski, Business Development Manager5thNovember 2014, Stuttgart

2. Contents
Short-wave Infrared Technology
Differences between SWIR and CCD/CMOS cameras
Industrial Applications & Benefits of Short-wave Infrared
-
Semiconductor
-
Photovoltaics
-
Glass Industry
-
Plastic Sorting with Hyperspectral Imaging
Conclusion
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3. What is Short-wave Infrared?
3
SWIR
900-2500nm
Visible
400-750nm
NIR
750-1000nm
2,500
400
750
1,700
900
1,000
Wavelength [nm]
CCD/CMOS
NIR Enhanced CCD/CMOS
Standard InGaAs
2,200
Extended InGaAs
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4. What differs a SWIR camera from a classic Machine Vision camera?
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Cooling Capability
Due to the higher Dark Current of
InGaAs sensors, cooling is necessary
InGaAs Detector
Sensitivity
between900 and 1,700 nm
High complexity level in the production process
Defect pixels on every sensor
Non-uniform pixel behavior
Higher dark current than CCD, CMOS
More Intelligence
Advanced image correction features
Non
-uniformity correction (NUC)
Defect
Pixel Correction
Background
Correction
3
2
1
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5. Basic Structure of a SWIR Camera
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InGaAs
Sensor
Optics
&
Filters
Sensor Cooling
Intelligence & Electronics
Interface
&
I/O Control
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6. Effect on the Image Quality with Cooling and more Intelligence
6
Sensor Temp. +40°C
100ms Exposure Time
1
ApplyCooling
Sensor Temp. -5°C
2
IncreaseExposureTime
800ms
3
ApplyIntelligenceNon-UniformityCorrection(NUC)
4
ApplymoreIntelligenceDefectPixel Correction
5
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7. A Selection of SWIR Applications
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Industrial Machine Vision

Semiconductor
Photovoltaics
Chemical (gas, plastic, foil)
Pharmaceutical
Glass Production
Agriculture
Food
Scientific & Medical
Optical CoherenceTomography
Microscopy
Hyperspectral Imaging
Laserbeam Profiling
Airborne Remote Sensing
Art Inspection
Security & Traffic

Surveillance

Vision Enhancement

NightVision

Homeland Security
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8. Semiconductor Industry
Applications
Silicon Crystal & Ingot Inspection
Wafer Inspection
Wafer Level Packaging
3D
-IC Defect Inspection with Infrared Microscopy
Photon Emission Microscopy
Photovoltaics
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9. What makes SWIR so special for Semiconductor Inspection?
Silicon gets transparent at wavelengths above 1,100 nm
SWIR has a great sensitivity at 1,000 nm
InGaAs
CameraQE of ≈ 76%at 1,000 nm
CCD/CMOS
NIR Enhanced CameraQE of ≈ 3% at 1,000 nm
The higher the thickness of the wafer (≈ >20μm), the more reasonable is an InGaAs camera
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76%
3%
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10. Luminescence imaging helps to identify non-uniformities in the silicon wafer or solar cell by forcing it to emit light:
Electroluminescence (EL)
Photoluminescence (PL)
Some emission effects to
characterize photovoltaics
intermediates are only
visible in SWIR …
… or partially with CCD/CMOS,
but with extreme long exposure times(Seconds instead of Milliseconds)
Thinfilm
basedsolar cellsshowothereffects
-
e.g. Copper Indium Diselenide(CIS) at a wavelength of 1,330 nm
What makes SWIR so special for Photovoltaics Inspection?
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11. Glass Production
Hot-End Glass Inspection
Monitoring of
glasstemperatureuniformitiesand coolingrate
Interior and exterior
inspection
Improvement
of yield and quality
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12. What makes SWIR so special for Hot-End Glass Inspection?
Typical: Temperature Measurement between 250°C to 800°C
Based on the Planck’s radiation law
Extended Temperature Measurements possible
SWIR cameras can image through glass
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Reference temps:
White hot steel ~1200
°C
Melting point of aluminum 660
°C
Water boils at 100
°C
Uncooled camera at 38 °C
Human body at 37 °C, radiates at
~ 10μm
Water freezes at 0 °C
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13. Hyperspectral Imaging (HSI)
HSI combines digital imaging with spectroscopy to obtain detailed information across multiple ranges of the electromagnetic spectrum
Applications:
Recycling & Plastic Sorting
Geology & Mineral Inspection
Pharmaceutical Quality Control
Food & Agriculture
Medical e.g. Disease Diagnosis
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14. What makes SWIR so special for Hyperspectral Imaging?
Eachinorganicmaterialhasadifferentchemicalcompositionandcrystallinestructureresultinginanuniquespectralresponsecorrespondingtoitsspecificlightabsorptioncharacteristics
Illustration
shows the unique information content of five different sorts of plastic starting with 1,000 nm
In general,
the higher the wavelength in the application, the higher the spectral information content
-
400 nm to 1,000 nm (basic information)
-
900 nm to 2,500 nm (extended or unique information)
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Source: Middleton Research
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15. Conclusion
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There are basically three technical differences between SWIR
and CCD/CMOS cameras
Photon detector material (InGaAs vs. Si)
Cooling capabilities needed to reduce noise
More Intelligence: Advanced image correction features
Take SWIR into consideration and explore your application with new eyes!
SWIR cameras offer new physical effects in the Short-wave Infrared spectrum
SWIR helps you to improve the yield in terms of quality, as well as productivity
Detect defects more accurately and much faster
Extraordinary reduction of exposure times
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16. Thank you very much!
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Paul Maria Zalewski
Business Development Manager
– Infrared & Scientific –
paul.zalewski@alliedvision.com
Allied Vision
www.alliedvision.com
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