Systematic Errors

• signal drifts in the registration circuits of spectrophotometric devices;
• inaccurate calibration of monitoring devices;
• vacuum shift;
• inaccuracy of tooling factors for witness glass.

These factors may result in the shift of measured transmittance/reflectance data as a whole or in the scaling them by a factor that differs from 1.

From a mathematical point of view, in the course of Systematic errors procedure only two unknown parameters are searched for. Optical coating model in this case can be described by vector \(X\):

\[X=d_1+\Delta_H, d_2+\Delta_L,…,d_m+\Delta_H(L)\]

\[ DF^2(\Delta_H, \Delta_L)\rightarrow \min\]

• OptiRE allows you to represent any errors as a sum of systematic errors and pure random errors with average value with respect to any layer material equal to zero (Normalize Errors);
• Correction factors present systematic components of the ratios of actual thicknesses to theoretical ones (useful for adjusting the deposition process)

Systematic errors procedure can be easily run from an external software with the help of COM Automation tool.