In 2017, we have developed a new technology
From January to May 2017 we developed production technology of the plate with 85 mm diameter. The main elaboration of this development was to withstand the conditions of small beam deviation (less than 5 arcsec) and the minimum deviation of Retardation Accuracy over the entire area of the plate. The new technology fully satisfies the conditions of small beam deviation (less than 5 arcsec). Retardation Accuracy at the edges of the plate has a deviation from the central part to 2 degrees. However, this does not violate the overall Retardation Accuracy ± λ / 100.