Thickness

Multi-layer and single-layer films

Low-coherence profilometers deliver fast and reliable non-contact thickness measurements of single-layer and multi-layer films – with precision better than 1 µm.

• Films and film stacks: 10 µm to several mm thick

• High-speed scanning: 1,000 to 30,000 points/sec and higher

• Real time thickness measurements: for substrates and for entire film stack

• Easy visual inspection: high-resolution depth profiles, 2D cross-sections (B-scans or C-scans) and 3D volumetric images

Materials may be reflective or nonreflective, smooth or rough, stationary or moving. See more on what we can measure.

• They acquire long profiles: probes acquire surface data one point at a time, at high speeds of 1 to 30 kHz and higher. No need for time-consuming surface tiling.
• They offer configuration versatility for benchtop or in-process inspection. Probes are mounted onto a benchtop or inline motion mechanism suitable for each application: X-Y table, galvo-scanner, rotational scanner, robotic arm, etc.
• Probes can work far from profilometer enclosure, as far as 1 km away, without signal degradation.
• Small probes reach inside to inspect interiors of small-diameter tubes, bores, etc. See inspection in hard-to-reach spaces.
• Rugged probes perform even in extreme temperatures or in radiation. See inspection in hostile environments.

Example of multi-layer thickness measurement

High-grade polymer tubing is closely monitored during extrusion. Dimensions must tightly adhere to specifications. A low-coherence profilometer probe acquires the cross-section of a medical catheter tubing continuously, right at the extruder exit (diagram on the right). An efficient production control loop is established:

• The probe acquires the thickness of the advancing thin tube as a long profile – at up to 30,000 points (A-scans) per second.
• Each A-scan delivers optical thickness of the upper wall, the enclosed air space, and the lower wall.
• Application software transforms optical data into physical dimensions of the tubing (table on the right).
• The index of refraction, IR, can be calculated if needed.
• Cross-section dimensional data is streamed to process-control software which adjusts extruder parameters in real time.

Continuous inspection cuts down on extruder down-time, reduces material waste, and lowers overall production costs.

Probe multiplexing for additional ROI

Several fiber-based probes can be multiplexed to a single detector for simultaneous thickness measurements on different aspects of a production line.

For example, the tube inspection setup above can be extended by adding a second probe at the extruder exit (diagram on the right). In this way, the operator is able to monitor tube dimensions along two axes continuously, achieving even greater quality control with minimal extra investment.