- Precision Layer Termination
- Reduced Process Error
- 350-2500nm Wavelength Range
- Superior Backgorund Noise Suppression
- Works in Reflection or Transmission Modes
- 5 Decade Dynamic Range
- Analog Output for Stripchart Recorder
- USB Interface
- Field-proven Design
- Monochrometer for continuous wavelength selection.
- Fiber Optic Input / Outputs
- Dual Receivers
Advantages of Optical Monitoring?
Optical Monitoring provides the highest accuracy needed for today’s precision thin film coatings. Crystal monitors, by design, only measure the mass of a coating layer and cannot detect changes in the layer density caused by a variations in one of the many process variables. If not caught, a change in layer density results in a variation of the optical thickness which can lead to dramatic performance reductions and possible lost runs and revenue.
Optical monitors, on the other hand, provide continuous real-time monitoring of the optical performance of each layer by measuring the reflectance or transmission of the coating throughout the coating run. This measurement is compared against a well known relationship for the optical thickness of each layer so that precise termination of each layer can be achieved.
Figure 1.0 below shows a typical plot of monitor chip reflectance vs. thickness generated by a coating design software package. The layer termination points noted by the solid vertical bars indicate the end points of each layer. When the 590 Optical Monitor readout reaches these points, the operator terminates that layer deposition and advances to the next layer.