Due to their technical design, large-field lenses are particularly suitable for the telecentric, monochrome inspection of large objects, test objects with deep contours or passages, magazined parts and for assembly and placement inspection.
The advantage of telecentric lenses, i.e. perspective-free imaging, was previously offset by the disadvantage that they were severely restricted in their use due to limited field of view sizes and were also expensive.
Due to the principle of using the parallel main beam path for imaging, the front lens of previous glass lenses had to be larger than the object to be examined. This means that as the size of the parts increases, the production of the optical components of the telecentric lenses made of glass becomes more complex, which is reflected in their price. Lenses of this type are also heavy, long and mechanically sensitive.
Advantages of Fresnel technology
This is precisely where the considerations for the telecentric large field lenses from Vision & Control come in. By replacing the glass front lens with a very finely structured plastic stepped lens (e.g. 10 zones / mm), it is possible to achieve significantly larger fields of view with telecentric lenses. The use of Fresnel lenses significantly improves the diameter-to-mass ratio and the diameter-to-length ratio. In this way, telecentric lenses with diameters of up to 600 mm are currently possible.
Telecentric large field objectives with Fresnel technology achieve previously unattainable fields of view with telecentric imaging.
The large field objectives with Fresnel technology can be used for monochromatic image processing in the VIS and NIR spectral range. All lenses are available with or without various filter elements.
Vision & Control has a selection of large field lenses that offer customers a wide range of applications and also represent the showcase for this technology. The newest members of the product family are the telecentric large field lenses vicotar® TL230 and vicotar® TL380, with object field diagonals of 230 mm and 380 mm respectively.
Telecentric large field lenses for line scan camera applications
Another new development is the vicotar® TLL400 and vicotar® TLL520 telecentric large field lenses designed for line scan camera applications. Here too, we offer a selection of standard products.
As an OEM service, it is possible to adapt customized large field lenses and deliver them comparatively quickly. The variations of customer-specific adaptation to the object field and camera connection are manifold.
Despite their small size, the vicotar telecentric large field lenses are designed for industrial use. Stable mountings ensure low-vibration installation. The dust-protected design, the adjustable and fixable aperture and the scratch-resistant front screen enable use even under unfavorable conditions. The standard lenses have a C-mount camera connection. Vision & Control's OEM service currently offers fields of view of up to 600 mm and camera connections for larger sensor formats such as M42 and M72.
published in Markt & Technik 39/2024