The laser scanning technology is often used in measuring the dimension of measurand. In this technology, f-(theta) lens is used as a correcting lens. In this paper, we use a normal lens replacing f-(theta) lens. Laser scans produced are directed through the normal lens to product a parallel beam across the gate area. We put a norm product in the gate area and get the relation of dimension of product and position in the gate area. With the relation of the position and dimension, we can make a curve-fitting and save the curve- fitting in an EEPROM. When we measure the dimension of product, with the different position the product in the gate area, we can have calculated the exact value of products by curve-fitting. In this paper, we show how to design the curve-fitting and how to use the curve-fitting to measure the dimension of measurand with a normal lens.
"Replacing f-θ lens with normal lens by curve fitting", Proc. SPIE 3557, Current Developments in Optical Elements and Manufacturing, (5 August 1998); doi: 10.1117/12.318331; https://doi.org/10.1117/12.318331