Machine Vision Lightings: LED Ring, Bar, Coaxial and Dome Lights

Machine vision lightings are LED illumination sources built for automated inspection and measurement. In most vision systems the light source matters as much as the camera and lens. Defects, characters and edges only show up reliably when the illumination geometry suits the part’s surface. Wavelength Opto-Electronic offers a wide range of geometries. You can match the light to the job, whether you’re reading laser marks on a wafer, checking print on a label, or finding scratches on polished metal.

Choosing an illumination geometry

The right light depends mostly on how your part’s surface reflects light.

• Ring lights mount around the lens and light the object evenly. Their compact structure makes them easy to install. Tilting the LEDs at different angles reduces shadowing.
• Shadowless ring lights use arrays of bright LEDs to form an even illumination area directly below the light. They suit character detection and reflective surfaces.
• Bar lights come in lengths from 10mm to several meters. You can combine them and adjust the illumination angle to cover large surfaces or set up low-angle lighting.
• Four-side adjustable lights have four independent light units, each with its own brightness control. This lets you tune directional contrast.
• Coaxial lights send light along the camera’s optical axis through a specially coated half-lens. This removes ghost images and shows scratches and marks on smooth, mirror-like surfaces.
• Coaxial parallel lights pass light from high-power LEDs through a specially coated lens. They are suited to laser engraving recognition and to finding tiny bubbles in glass.
• Coaxial flat lights combine coaxial and shadowless illumination. They help on highly reflective parts with bumps, dents, cracks or ripples.
• Flat and flat parallel lights spread LEDs evenly to give uniform backlighting for profile and size measurement.
• Broadside flat lights place LEDs around the edges and use total internal reflection to turn that edge light into a flat illuminated field.
• Hole flat lights give soft, even light through a central aperture. At low working distances the effect is close to ambient light. At higher working distances it is closer to coaxial light.
• Dome, tunnel, line, point, IR and UV lights complete the range. Domes and tunnels are for curved or complex shapes. Line lights pair with line-scan cameras. Point lights give localized illumination. IR and UV sources cover inspections outside the visible band.

Applications by industry

• Semiconductor and electronics: laser marking on wafers, electronic component inspection, and checking parts on substrates.
• Display and glass: LCD screen defects, mobile phone screen positioning, glass defects, and contour and size measurement.
• Metal parts and bearings: reading QR codes printed on metal and glass, detecting scratches and marks, and inspecting metal surfaces.
• Packaging and labeling: character and print inspection, label checks, damaged packaging, stretch film breakage and broken masking tape.
• Pharmaceutical and medical: checking medicine mixes, and inspecting labels and packaging on production lines.
• Liquid handling: checking liquid levels with broadside flat backlights.

Configuration and brightness adjustment options vary by type. Check the specification table for the diameter, angle, color or wavelength, voltage and power of each part number.

Why buy through Wavelength Optics USA

Wavelength Optics is the US arm of Wavelength Opto-Electronic. Buying through us gives you a local point of contact for the full machine vision lighting catalogue.

• Local support: you work in US business hours with engineers who understand your application.
• Fast quoting: send us part numbers or a description of your inspection task, and we’ll come back with a quote.
• Help with selection: choosing between coaxial, dome, ring or backlight geometries is often the hardest part of a vision project. Our team can recommend a light type, color and size based on your part’s surface, working distance and camera setup.

Contact Wavelength Optics USA to discuss your inspection requirements or request a quote.