In the recent past, telecentric lenses have grown in popularity due to their ability to undertake high accuracy measurements and repeatability which in turn maximize the output of machine vision systems. Telecentric lenses appear to be heavier, larger and quite expensive when compared to normal lenses. Their main advantage is providing the highest possible accuracy that can be obtained in machine vision systems since its magnification never changes with respect to depth.
Similarly, telecentric lenses have a lower distortion value than fixed lenses. Distortion makes an object seem as if it were in a different location, which alters the accuracy of a measurement. Furthermore, a telecentric lens solves problems associated with poor image resolution. Telecentric lenses resolution is quite compatible with small pixels and cameras with high resolutions, therefore, increasing measurement resolution.
It is recommendable to put telecentric lenses to use especially when the profile of a piece is required, the brightness of an image must be even, and when the object to lens distance cannot be predicted. Also, it can be put to use when different measurements on different object planes have to be carried out. Mostly, telecentric lenses are used in making patterns in semiconductor chips, metrology and scientific research, machinery components, printing, and laser diameter among others.
In conclusion, Telecentric Lenses aim at offering the highest image resolution of a machine vision. It can have pixels smaller than 3 microns and mostly operate in the range of 365 to 425 nm. They can produce a higher image contrast when you have high spatial frequencies. Their benefits include offering better magnification constancy which helps in overcoming accuracy issues, increasing field depth which helps maintain a good image contrast, especially when viewing thick objects and an even illumination of the detector which aids in print quality, textiles and LCD.