FTBP Series
Inline Filters for TC Series Lenses
Light filtering is a typical need in machine vision applications. Together with LED illuminators, filters can improve image contrast by blocking unwanted light and increase the accuracy and repeatability of the vision system.
Ambient light can cause errors in imaging systems due to unwanted reflections off the surface of the parts being measured. In these cases, a band pass or long pass filter that matches the emission wavelength of the illuminator is usually integrated in front of the imaging lens: this way, only the light coming from the illuminator is collected while the rest of the spectrum is cut out.
In addition, many machine vision applications require monochrome illumination in order to enhance or suppress particular object features: under these conditions, only the features with a certain color are imaged and inspected.
Placing a filter on the object side of a bitelecentric lens can be expensive, as the diameter of a telecentric lens needs to be at least equal to the diagonal of the field of view.To overcome size and cost issues, Opto Engineering® designed a smart filter adaptor that can be easily plugged into the camera-side of the lenses. This convenient and cost-effective accessory is compatible with all TC12yyy and TC23yyy bi-telecentric lenses, as well as the C-mount versions of TC4M and TC2M series bi-telecentric lenses.The bi-telecentricity of the Opto Engineering® lenses makes this solution very efficient, since the rays remain parallel when passing through the filter. This allows for the optical bandpass to be maintained across the entire image surface.Since inserting the filter will increase the back focal length of the lens, spacers (included in the TC lens package) must be added to the C-mount in order to set the lens back to its nominal working distance; the overall thickness of the spacers is usually equal to 1/3 of the filter thickness.The supported filter diameter is 17.50 mm and the maximum recommended filter thickness is 4.00 mm. |  |