Tailored SWIR lens supports high-accuracy plastics sorting

Manufacturers of plastic sorting and inspection systems are increasingly turning to application-optimised SWIR (Short Wavelength Infrared) lenses to improve the efficiency and accuracy of recycled plastics recovery.

SWIR spectroscopy enables rapid identification of plastic types such as LDPE, HDPE, polypropylene, PTFE, polystyrene, and PVC  -  critical for automated sorting in automotive, electronic and household waste streams. However, not all lenses are suited to the high-resolution InGaAs detectors used in these systems.

Rob Watkinson, Sales Manager at Resolve Optics, explained:

"Many so-called SWIR lenses are simply visible-range optics with a SWIR-specific AR coating. These don’t account for how glass behaves in the SWIR region, leading to compromised image quality - especially when paired with high-resolution sensors.

“While off-the-shelf lenses may seem cost-effective, they often result in lower performance, reduced resolution, and bulkier designs. These trade-offs can ultimately limit the effectiveness and appeal of recycled plastics sorting systems. That’s why demand for our instrument-optimised Model 363 SWIR lens has grown significantly in this sector.”

Resolve Optics’ 16 mm focal length Model 363 is specifically engineered for SWIR imaging, using selected glass types and coatings to deliver maximum transmission, colour correction, and image clarity across the SWIR spectrum. The lens offers an f/1.6 aperture and less than 2% geometric distortion, producing a sharp 12.8 mm diameter image ideal for modern sorting applications.

With over 20 years of experience in optical design for inspection and sorting systems, Resolve Optics continues to support innovation in the recycling industry with custom and off-the-shelf lens solutions.

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