Chromatic White-Light Sensor - Non-contact, high-resolution and fast surface measurement

The CWL is based on the principle of chromatic distance measurement. White-light from a high-performance LED is focused on the surface by a measuring head with a strongly wavelength-dependent focal length. The spectrum of the light scattered on the surface generates a peak in the spectrometer.

The wavelength of this peak is used to determine the height on the sample. The sensor works on transparent, highly reflective or even matt black surfaces. It is extremely fast and has virtually no edge effects.




Sensor: CWL 



Measuring Principle
   
  • non-contact, non-destructive measurement
  • very high resolution possible due to small spot,
    low-maintenance LED light source
  • suited for use in difficult ambient conditions
  • coaxial measurement, no edge effects
  • small, wear-free sensor without moveable parts

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Typical Applications
 
  • quality checks in front-end and back-end fabrication of
    semiconductors (e.g. wafer, die, packages)
  • R&D and quality control in micro systems engineering
    (e.g. MEMS, inkjet print heads)
  • R&D and quality control in medical technology
    (e.g. stents, catheters, prothesises)
  • quality checks in the automotive industry
    (e.g. interior, cylinders, shafts)
  • quality checks  of circuit boards, injection moulding (micro-)parts,
    optical components (e.g. lenses)
  • profile and 3D-measurements on heavily structured surfaces
    (e.g. tools, rollers, components)


Technical Specifications
   
measuring range z 300 µm 600 µm 1 mm 3 mm 10 mm 25 mm
working distance 4.5 mm 6.5 mm 20 mm 22 mm 70 mm 76 mm
max. resolution z1 3 nm 6 nm 10 nm 30 nm 100 nm 250 nm
resolution x, y 1-2 µm 1-2 µm 2 µm 5-6µm 12 µm 12.5µm
measuring angle 90° ± 30°2 90° ± 30 °2 90° ± 40 °2 90° ± 30 °2 90° ± 20 °2 90° ± 15 °2
 1 Maximum resolution based on reduced measuring range.
 2 Diffusive surfaces allow for wider measuring angles.