| 摘要 |
A process for determining the thickness and/or change in thickness of a thin layer applied to a carrier, with the carrier coated with the thin layer being radiated with a plane polarized light beam and the reflectance on carrier and layer being detected. The light reflected by the carrier and the thin layer is split into a p-polarized part and an s-polarized part, after which the respective reflection values Rp and Rs are measured simultaneously for the two parts, and the quantity M = is determined, in which formula m is a variable parameter and the quantity M is a function of the thickness of the thin layer. By measuring both the reflection of p-polarized radiation and that of s-polarized radiation, and by adroitly combining the measuring data obtained, the resulting signal will be insensitive to the intensity of the radiation source. An additional advantage is that the process has a greater sensitivity to variations in layer thickness, and that it is possible for the process to be carried out within a wide linear measuring range. In determining the growth of a protein layer the measuring result is independent -within wide limits- of the thickness and the index of refraction of a layer previously applied to the carrier. |
