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Mantova, Italy, 2008/10/29 - UV Telecentric Lenses can efficiently operate with pixels as small as 2 micron and for this reason these lenses can be successfully used in all those applications using very high resolution cameras and seeking for the highest possible accuracy.
Common machine vision lenses and traditional telecentric lenses operate in the visible light range. Machine vision integrators, since now, have been using visible optics because they want their camera to see what their eye is able to see.
Unfortunately this approach, similar to photography, shows now some limitations when applied to systems where very small pixel size cameras are used in order to achieve very high measurement resolution. In fact, the limiting resolution of a lens is given by the cut-off frequency, the spatial frequency (usually expressed in line pairs/mm) at which the lens is no longer able to yield image contrast information.
As the cut-off frequency is inversely proportional to the light wavelength, common machine vision lenses and telecentric optics operating in the VIS range are useless with very small pixel sizes (which can reach sizes as small as 1.75 micron) which are becoming increasingly popular among industrial cameras.
For this reason Opto Engineering has developed a new family of Telecentric Lenses operating in the UV (TCUV Series) which have been specifically designed to ensure the highest image resolution today achievable with a machine vision system. UV Telecentric Lenses can efficiently operate with pixels as small as 2 micron and for this reason these lenses can be successfully used in all those applications using very high resolution cameras and seeking for the highest possible system accuracy.
UV Telecentric Lenses, by operating in the 365/425 nm range, provide much higher image contrast at high spatial frequencies and are therefore compatible with the tiniest pixel sizes. On the other hand, used in combination with normal cameras, the resolution of these lenses is so high that they can tolerate object displacements much larger than VIS lenses before any image defocusing becomes evident. Therefore the field depth is also increased when compared to standard, VIS-operating, telecentric lenses. UV Telecentric Lenses can work with any kind of UV illuminators operating in the 356 ... 420 nm range, like ring, coaxial and back light illuminators equipped with UV LEDs.
However the best choice for measurement applications are LTCLUV LED Collimated Illuminators providing image resolution and field depth enhancement.
These Telecentric Illuminators ensure an extremely efficient coupling between an UV LED source and the UV Telecentric Lens by back-lighting the object with the most appropriate geometry. With this very efficient configuration UV enhanced detectors are not needed while any CCD or C-MOS camera can be integrated.UV Telecentric lenses combined with a proprietary optical technology developed by Opto Engineering (opto-engineering.com) are providing the unique imaging technique, TC EDGE, which ensures that only the rays deviated by an object’s edge are imaged on the detector plane. Edges are automatically extracted by the lens system without any need of software algorithms; this technique makes it possible enhancing tiny defects, particles and surface discontinuities which cannot be viewed by any other type of lens system.