G4000MR vacuum coating system

Overview

The G4000MR vacuum coating system is a production-scale coater designed for producing uniform reflective and protective coatings on large-size optical articles including astronomical primary mirrors. It is configured to process articles of up to 4 m in diameter using small software-controlled magnetrons that move along a calculated path at adjustable speed, with magnetron movement speed and mirror rotation speed matched to achieve exceptionally uniform coating thickness. The mirror is positioned face down and is rotated several times during the cycle, and prior to deposition the mirror face is plasma-treated with a movable ion source; the specified pretreatment device is a DC Gridded Ion Source. Coating deposition is performed by metal and reactive magnetron sputtering using three circular planar magnetrons powered by pulsed-DC power supplies, while quartz-crystal resonator devices are used for controlling the deposition rate. Vacuum is provided by refrigerator cryo-pumps and a turbo pump connected to a Roots blower and dry compressing pumps, the control system ensures a fully automated process, the unit supports coatings such as Al, Ag, SiO2, SiNx and NiCr, can process 1 pc. substrate per cycle, and requires floor space (L x W x H) of 23 x 14 x 5.15 m. The G4000MR is used to produce uniform reflective and protective coatings on large-size optical articles, including astronomical primary mirrors. It is intended for depositing reflection coatings of Al and Ag and for applying protective dielectric and other layers such as SiO2, SiNx and NiCr onto large-size astronomical glassceramic mirror substrates up to 4 m in diameter.