Bi-telecentric lenses for a broad range of applications

Vision & Control has added a new series of bi-telecentric lenses with an object field diagonal measurement of 42 mm to its range, which are telecentric on both the object and image sides. Thanks to a wide spectral range from white to near-infrared, these lenses open up versatile applications for measuring technology and quality control.

Bi-telecentric lenses TOB42

vicotar® TOB42 series

The vicotar® TOB42 series offers a new range of robust, bi-telecentric lenses with a large object field. Because the optical path is parallel on both the object and image sides, bi-telecentric lenses do not suffer from distortion of perspective. In addition, the size of the depicted objects remains constant within the depth of field. This enables precise series investigations of size and position even in cases where the test objects are not always at the same distance from the lens. Since no details are covered up, even geometrically difficult objects (spheres, indentations, irregular edges, deep holes) can be accurately investigated. Likewise objects with optically critical surfaces made of glass or plastic. This opens up a new world of possibilities in terms of inspections for presence, completeness, or quality control.

At present, the TOB42 series encompasses three fast lens groups for working distances of 145 mm, 165 mm, and 185 mm. These all have an object field diagonal measurement of 42 mm and a sensor diagonal measurement of 11 mm on both sides and are suitable for image recorders up to 2/3” in size. They also share high telecentricity on the object side, with a telecentricity angle of below 0.05°. They are available with a variable (F6 to F22) or fixed aperture (F10, F16).

The lenses are designed for the spectral range from blue (450 nm) to near-infrared (950 nm). This makes them particularly well suited to multispectral applications, for example in the inspection of semiconductors. They work perfectly together with high-resolution 9 megapixel sensors down to a minimum pixel size of 2 μm.

Depending on the working distance, the lateral color aberration varies from 3 μm at 145 mm to a maximum of 9 μm at 185 mm. For most applications, this therefore places the aberration below the pixel size of the image sensor. The distortion is also extremely low. At 145 mm it is below 0.12%, at 185 mm it is less than 0.25%.

Thanks to their compact size and robust design, the TOB42 lenses can also be used under cramped conditions or in harsh industrial environments, for example mounted on the arm of a robot. It goes without saying that this series of lenses works with the entire product portfolio of Vision & Control – all cameras, lighting systems and accessories.