Measurement 1Reflective Displacement Sensor
When light is directed at a transparent target, light is reflected from the top and bottom surfaces. Thickness is measured by calculating the difference in position of the light reflected from the top and bottom surfaces.
Displacement sensor selection is important
- Does the displacement sensor have enough range to see both the top and bottom surfaces?
- Check to see if stable measurement is possible even if the reflectance of the top and bottom surfaces is different.
- Spectral Interference Method.
- Ultra-stable measurement with single layers or multiple layers.