The focus of the OSeeT are enteric coatings (EC) and modified-release (MR) coatings.
The characteristics of the coating layer are revealed via OSeeT:
Mean coating thickness
→ progress of coating process
Intra-particle and inter-particle coating variability
→ for quality and homogeneity of the applied coating
Roughness
→ optical quality of the surface
The Technology behind OSeeT is Interferometry
- OCT is based on white light interferometry:
– broad bandwidth resulting in low-coherence length
– defines the axial (=depth) resolution - Light is split into a reference and a probe path
- Optics of sample arm focus light and define lateral (=surface) resolution
- Interference of light reflected back from both paths
- Spectrometer (grating, CCD line scan camera)
- Depth-information is generated from interference fringes by Fourier-transformation (FFT)
- Measurement of a single depth scan
