I am currently investigating how light emitted from a sample is propagating through a telecentric lens onto a CCD. For this, I request some guidance on how simple a model I could implement is, as I do not use commercial software for this problem. Could it actually be a good approximation to describe it as an infinitely thin lens? Simply using a working distance, focal length and possibly a truncation of the objective minimum pupil in the objective?
As I recall from the previous work, the primary advantage of modelling the lens more accurately is to allow quantification of distortion effects, so for a telecentric lens this might actually be a rather good approximation?
Thank a lot for your input.
Kind regards
Otto
As you know paraxial lens is a perfect lens.Therefore, if you design a telecentric lens system with it, you will get a perfect telecentric system and so not see any effects of aberrtions. You can see this in attached ZEMAX file.
Hi Cevdet,
thanks for taking the time to answer and sharing the Zemax file. Zemax provides two solutions for this on their homepage. The problem is however, that I need model the lens in another homemade traytracing program, which mean I have to design the transmission matrix my self.
Again thanks.
Telecentric lens is useful for optical metrology and machine vision. Telecentric lens can produce constant magnification as displacement of an object and minimum image distortion. To yield constant magnification, the chief principal rays must be parallel to the optical axis. This optical behavior can be obtained by positioning the stop aperture exactly on the focal plane of the front optical group: the incoming rays aim at the entrance pupil which appears as being virtually placed at the infinity. See http://www.opto-engineering.com/resources/telecentric-lenses-tutorial.
A small position change in object side and image side in a double-sided telecentric lens system does not cause the magnification change, which makes those lens systems more robust for on-site measurement. The design parameters of the three-component double-sided telecentric zoom system are powers on the components and interval distances between the components. Juntong Xi, et al. had developed a method to analyze the paraxial design parameters for a three-component double-sided telecentric lens system, see “Paraxial analysis of double-sided telecentric
zoom lenses with three components”, Applied Optics 53 (22), pp 4957-4567 (2014).
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