SWIR Cameras, Lenses, and Lighting

SWIR Cameras

R.J. Wilson, Inc. is offering cameras from SWIR Vision Systems to expand the range of applications that can be addressed using ShortWave Infrared imaging (SWIR)These cameras feature patented CQDTM Sensors, based on colloidal quantum dot (CQD) technology.   CQD technology reduces the cost per MP of SWIR cameras, compared to those using indium gallium arsenide (InGaAs) sensors. 

SWIR (Short-Wave Infrared) refers to the light wavelength range of 900nm to 2,500nm. SWIR light behaves similarly to visible light, in that photons are reflected or absorbed by an object, providing the strong contrast needed for high resolution imaging. Like visible light cameras, SWIR cameras deliver high resolution images at high frame rates and offer selectable bit depths of 8, 10, 12, and 14 bits.  

 SWIR imaging is especially good for:  

  • Imaging through siliconwhich appears nearly transparent 
  • Checking liquid fill levels in opaque plastic containers with labels 
  • Determining whether clear adhesive has been applied 
  • Viewing the contents within opaque plastic or paper product packaging  
  • Viewing the dampness or liquid coatings coverage of in-process goods, as liquids absorb certain SWIR wavelengths 
  • Viewing anomalies in hot glass containers earlier on the production line 

 The following examples highlight some of the application spaces that can be addressed: 

Semiconductor Wafer Inspection

There are many application spaces using SWIR cameras and lighting for the inspection of silicon and gallium arsenide semiconductor wafers and photovoltaic cells. Certain SWIR lighting wavelengths pass through these wafer materials and chemical depositions. SWIR light wavelengths will not pass through metal, so objects such as bumps, circuits, and alignment targets will be visible.   

 SWIR imaging enables alignment mark and wafer bump inspection on bonded wafers  

Alignment Targets on Bonded Wafer Layers Can be Imaged 

SWIR imaging can be used to detect micro-cracks and chipping near the edge of diced wafers that can’t be seen in visible light imagesThe cracks interfere with the SWIR light transmission to make these defects visible.  

The SWIR Lighting Path is Interrupted by the Crack in the Silicon, Making it Visible 

Voids, air pockets, and particles can be detected in the wafers. 

Detection of Voids in New Wafers 

Opaque Paper & Plastic Packaging

The contents or features within opaque and printed paper and plastic packaging become visible and inspectable when backlit with SWIR lighting. 

 In the following example, the printed opaque plastic bag is backlit at 1450nm and the bag edge, the zipper, and the vacuum seal areas are visible without interference from the printing on the bag. The bag may then be inspected to ensure none of the contents is stuck in the zipper or in the vacuum seal areawhich may lead to leaking or spoilage. 


SWIR Lighting Passes Through the Printing, Making it Easier to Inspect Key Features 

In the example below, the contents within plastic packaging become visible because the SWIR back and front lighting pass through the printed packaging. This is ideal for food packaging inspection to verify the contents are correctly packaged or are present at all. The same concept may be applied to medical and surgical products packaging. 

The Packaging Disappears, Permitting Inspection or the Verification of Presence of the Contents 

Liquid Levels & Liquid or Adhesive Presence

Liquids typically absorb specific SWIR wavelengths and can appear dark, enabling fill-level verification behind plastic labels or within tinted or opaque vials and bottles.  


SWIR Lighting Passes through Labeled Vials and Plastic Packaging to Detect Fill Levels 

Since liquids and adhesives absorb specific SWIR wavelengths at varying degrees, based on their chemical composition, additional applications requiring the detection or differentiation of clear liquids or contamination, liquid coating coverage, and clear adhesive presence on surfaces can be addressed.  

Produce and Moisture Content Inspection

Water absorbs 1,550nm and other SWIR wavelengths, making it appear dark in the acquired image. In produce sorting, bruises, as shown below, appear as dark spots based on the increase in water content at that location 

SWIR Light Highlights Where the Water is Concentrated, Making it Easier to Image Bruising 

The ability to detect water or liquid can also determinwhether the item is dry or wet, and ready for further processing, such as checking grain moisture content, dyed textile moisture, processed particle board moisture content, and for seal/packaging inspection of high-moisture goods.  


Hot Glass and Molten Metal Inspection

Although not a true thermal camera in terms of measuring temperatureSWIR imaging is used to inspect hot glass products, looking for temperature uniformity variations that present themselves as grey value variations in the acquired image. These localized temperature variations often lead to defects in the glass. 

SWIR imaging is able to look through the glass to inspect the far “walls” for temperature variations. It’s less costly to “recycle” defective glass products at this point in the manufacturing process than after the glass completely cools. 

View of Glass Bottle Imaging with a SWIR Camera, No External Lighting is Required

SWIR imaging can also be used to inspect molten metal. It can help differentiate between the molten metal and the slag, through imaging the differing grey values, because of the variation in temperature between the two. The presence of slag in the molten metal will impact the quality of the subsequent process or the final product. 

SWIR Vision Systems Cameras Provide:

  • Acuros™ CQD™ 640 Camera – 640 x 512 pixels at 380fps 
  • Acuros™ CQD™ 1280 Camera – 1280 x 1024 pixels at 90fps 
  • Acuros™ CQD™ 1920 Camera – 1920 x 1080 pixels at 60fps 
  • Full Visible-to-SWIR bandwidth, 400-1,700nm response, with 2,100nm response in Extended SWIR models 
  • Selectable bit depths of 8, 10, 12, and 14 bits 
  • Global shutter 
  • Thermo Electric Cooling™ (TEC) for low noise 
  • Pixel non-uniformity correction
  • USB3 Vision and GigE Vision interfaces
  • Compatible with range of SWIR lenseswith C, F, and M42 lens mounts 
  •  Software GUI for camera control included
  • SDK included for user development included
  • Unlike many InGaAs cameras, Acuros™ CQD™ cameras are non-ITAR and are designated as EAR-99, with no export license required

SWIR Lenses, Standard & Telecentric

SWIR Lenses

Although standard visible wavelength glass lenses can sometimes be deployed with SWIR cameras, SWIR-specific lenses include optical coatings that enhance the focusing capabilities, contrast, and image quality within the SWIR range.

Factory automation lenses for SWIR imaging are available as standard and telecentric lenses in a range of focal lengths, magnifications, and camera mounts from our lens partners at Goyo, Navitar, Opto Engineering, SWIR Vision Systems, VS Technology, and others.

High Magnification SWIR Lenses

Applications in the semiconductor industry, such as bonded wafer alignment target imaging, require the use of high magnification optics. Navitar’s Resolv4K modular high magnification lens system is available with special SWIR coatings to permit its use with SWIR Vision Systems cameras. The wafer images shown herein were made with the Navitar Resolv4K lens system with the SWIR coating  To get even higher magnification out of the Resolv4K, SWIR-capable change to “Typical SWIR lighting wavelengths include 1,050, 1,200, 1,300, 1,450, 1,550, and 1,650nm.  Additional information on the Navitar Resolv4K high magnification lens system is available on our High Magnification Lens Page. 

Navitar Resolv4K and Other High-Magnification Lenses are Available with a SWIR Coating

SWIR Lighting

SWIR lighting is available in a variety of form factors and in specific SWIR wavelengths for back lighting or front lighting. Effilux and Smart Vision Lights offer a range of SWIR lighting options.  

SWIR Lighting Form Factors 

Typical SWIR lighting wavelengths include 1,050, 1,200, 1,300, 1,450, and 1,550nm.  

 For additional information on SWIR lighting, please visit our SWIR Lighting Page. 

 To discuss whether SWIR imaging can solve your inspection challenges and to arrange an evaluation of your parts, please contact R.J. Wilson, Inc.