Patent ID: 7435300

Claim:
A dynamic film thickness control system providing control of a coated film thickness on a substrate comprising: means to move a transparent substrate laterally from a first end towards a second end across a face of the mask plate and a vapor source wherein the mask plate is located between the substrate and the vapor source and the vapor source is disposed on a side of the mask plate closer to the first end so that a surface of the substrate currently undergoing deposition is exposed to the vapor source and after having deposited on it a predetermined thickness moves behind the mask; a film thickness monitor to measure the thickness deposited on the substrate in real-time by projecting a light from a source from outside the coating vacuum system, through a first window on the vacuum system or through a first optical fiber, through the transparent substrate in the coating vacuum system, through the film being deposited through second window on the vacuum system or second optical fiber and on to the detector in the given order; wherein, the movement of the substrate is controlled by the control system according to the thickness value determined by the said detector so that a surface area after acquiring a predetermined thickness moves behind the mask plate to allow successive surface areas of the substrate get exposed to the vapor source.