wenglor’s New Ring Light and Dark Field Attachment Assist Machine Vision

wenglor sensoric group has announced that its newest light source, the LRL ring, is now available. This ring of bright light can enhance machine vision and inspection operations by providing powerful light from a ring of LEDs. The bright LEDs reduce the impact of ambient lighting conditions, leading to more accurate measurements and less intervention from technicians during inspection operations. Also, the LRL ring can be equipped with a dark field illumination attachment, making it more versatile for these measurements.

The new wenglor LRL ring light is available in two sizes and three light colors. Image used courtesy of wenglor

wenglor LRL Ring Light

The newest LRL ring light addition to the wenglor line of illumination products is available in two sizes (37 mm and 76 mm, matching popular industry cameras) and three LED colors (white, red, and infrared). The ring lights are built to be compatible with a dark field illumination attachment and angle changers that allow for illumination from different angles, all while avoiding shadows. Furthermore, the LRL ring can be operated in continuous or strobe mode and can be dimmed throughout a continuum to meet the demands of the specific application.

There are numerous flexible mounting options for the LRL ring, making it easy to deploy in existing machine vision systems. It has an anodized aluminum housing rated to IP67, testifying to its ruggedness for virtually any manufacturing or industrial environment.

The dark field attachment enables visual inspection of hard-to-see surfaces, such as those that are glossy or dark. Image used courtesy of wenglor

Dark Field Illumination

Dark field illumination is a photographic technique that highlights edges, corners, topography, and other key features used in inspection. It assists machine vision systems with detecting features, making automated inspection easier.

In order for this to be possible, light is directed at the object at oblique angles. Then, filtering, camera settings, and other tricks are used to collect only the scattered light. Because light is scattered only at the edges, corners, defects, and other such areas, the image's background is dark, and the key features are lighter. This creates a high-contrast image of the object, making it easy to measure distance, locate defects, etc.

The LRL ring can be modified with wenglor’s ZMRG dark field attachment, making it possible to perform dark field imaging. This is particularly useful for finding defects in shiny, glossy, or smooth surfaces where bright lights can mislead standard imaging.

The LRL ring light depicted aiding machine vision cameras that are inspecting car seat frame mounting holes. Image used courtesy of wenglor

Machine Vision Applications

Machine vision inspection is the primary market for wenglor’s new LRL ring light. One example of how machine vision can improve the inspection of finished goods is in the printed circuit board (PCB) market. PCBs can be glossy, making it challenging to ensure that all of the traces are continuous. However, with dark field illumination, broken traces will stand out more clearly. Automated inspection can flag PCBs that have a broken trace.

The key market for the LRL ring light is automated machine vision inspection equipment. The ability to drown out ambient lighting conditions, perform dark field illumination, and yet use little power means machine vision tasks can be performed more quickly and confidently. In particular, the dark field illumination technique allows for automated measurements, such as distances between edges, inclusion or defect count through automated pixel-counting algorithms, and other such operations.