Controlling an evaporation rate of an evaporant in a vacuum coating plant, comprises determining evaporation rate of evaporant in vacuum chamber, and adjusting sheet property by control algorithm using Smith predictor and controller

摘要

The method comprises: determining an evaporation rate of an evaporant in a vacuum chamber; adjusting (3) a dead time measured sheet property by a control algorithm using a Smith predictor (2) and a controller (4); and integrating a mapping model in a pre-filter (5) to compensate the properties of the evaporant and an electron beam power passed over the coating source. The coating source is designed as a rectangular cup or a rotary crucible with a defined pattern through which the electron beam is passed for uniform evaporation of evaporant. The method comprises: determining an evaporation rate of an evaporant in a vacuum chamber; adjusting (3) a dead time measured sheet property by a control algorithm using a Smith predictor (2) and a controller (4); and integrating a mapping model in a pre-filter (5) to compensate the properties of the evaporant and an electron beam power passed over the coating source. The coating source is designed as a rectangular cup or a rotary crucible with a defined pattern through which the electron beam is passed for uniform evaporation of evaporant. The predefined pattern is divided into primary and secondary movements, where the primary movement is performed in an x direction, and the secondary movement is performed in a y-direction. The Smith-predictor supplies an average evaporation rate to compensate the random errors during the coating process, where the average evaporation rate is independent of a current coordinate. The compression and the granularity of the evaporant, and the temperature and stoichiometry of the electron beam of the controller is preset, increased or decreased to compensate the systematic errors, in particular irregularities in a surface profile of the crucible. The electron beam power depends on the current coordinates of the crucible.