Multi-peak white light interferometers enable high precision multi-layer measurements
19.05.2022
Micro-Epsilon white light interferometers are characterized by their outstanding precision and absolute measurement values. The industrial-grade devices are suitable for inline use for machine integration as well as for laboratory applications. White light interferometers measure distance as well as thickness, achieving nanometer accuracy at picometer resolution.
With the new multi-peak versions, high-precision detection of multiple transparent layers in just one measurement process is now also possible. Two controller models are available for multi-peak distance measurement (IMS5x00-DS/MP) or multi-layer thickness measurement (IMS5400-TH/MP). The difference between the two is that with the distance system, the layer thicknesses are calculated from the respective distance values, but are measured directly with the thickness system. Depending on the application, this gives you different benefits:
Systems for multi-peak distance measurements are used in particular for alignment and positioning tasks where distance and thickness are to be determined at the same time. In a large measuring range of 2.1 mm, up to 13 layers with minimum thicknesses down to 10 µm (BK7) can be detected. In relation to the accuracy, the measurement is made from a large distance of around 19 mm. Thanks to the absolute measurement, the system does not have to be referenced even after a signal interruption, for example in the case of steps or edges.
Systems for multi-layer thickness measurement are always used when distance-independent thickness values for up to 5 layers are required. In the thickness measuring range of 2.1 mm, single layers down to 35 µm (BK7) are measured reliably. The large working range compensates for distance fluctuations of the measuring object, so that vibrations or other material movements do not influence the measurement. Another advantage of the thickness systems is their large offset distance: measurements are taken from up to 70 mm away from the target, which provides process reliability and protects the sensor from being damaged.
A modern and intuitive web interface for easy system configuration is available for all systems. In addition, the diverse interfaces (EtherCAT, Ethernet, PROFINET, EtherNet/IP, RS422, analog) offer numerous integration options. For industrial use, the interferometer sensors are equipped with a high protection class of IP65. Vacuum-compatible systems are also available as an option.
Advantages of the white light interferometer
- Best-in-class resolution <30 pm
- Linearity up to ±10 nm for nanometer precision
- Distance-independent thickness measurements
- Up to 13 layers with minimum thicknesses up to 10 µm measurable
- Robust system for process-stable measurement results
- Large distance to the measuring object at 2.1 mm measuring range
- Pilot laser visualizes measuring point and provides optical feedback on measuring position
