database and the volume of gas flow is determined by the requirements of the refractive indices of different films ranging from 0 to 40 sccm if the coating is nitrides there is no need to replenish n 2 into the chamber only in the ion source however if the coating is oxides or oxide nitrides then the ion source is composed of o 2 or o 2 n 2 mixture and the chamber is replenished with o 2 the mixture ratio of n 2 and o 2 and its flow rat e is between 0 to 40 sccm but under no circumstances should the rate make the vacuum extend to 7 u00d7 10 u2212 2 pa the rate of n 2 and o 2 mixture is 0 to 100 of ar content in addition the ion beam voltage and current of the ion source and the temperature of material should be adequately adjusted in order to obtain the most appropriate film quality adjustments include let partial of o 2 flow into the ion source and partial into the coating chamber control the density of ion current within the range of 10 u03bca cm 2 to 80 u03bca cm 2 better within 30 u03bca cm 2 to 50 u03bca cm 2 and the ion beam voltage v b ranges from 150v to 800v different refractive index profiles can be used as a function of deposition parameters and thus have to be stored in a computer database in accordance with the refractive index database the thin films required can be produced by a variety of deposition methods only inputting the layer thickness and refractive index necessary for designed multilayer thin film.