Xelas INLINE-oled

Inline Measurement of OLED –
Fast and Safe Thickness Inspection

High-efficient production of organic light-emitting diodes (OLED) need accurate thin film thickness control of the coatings of many different materials. Real-time measurement on the one side must be combined with true thickness values output on the other side. This enables OLED production to run in high speed and with correct layer thicknesses.

Unlike other applications, in the case of OLED, there is no space for “B”-quality, thus an accurate control of the layers is essential. To keep the values stable one needs a measurement equipment, being robust to disturbing influences, like sample height variations or tilt with respect to the standard measurement level.

Special optical design is needed to provide accurate spectral measurements in reflectance and transmittance, from which the thicknesses are determined in fast speed.

Stability of reflectance with respect to deviations in z-direction from the normal production level

OLED inline measurements

NXT offers unique equipment to measure the layer thicknesses of any kind of layers or stacks. Surface roughness is taken into account as well.

The system’s optical RT-heads are designed and optimized for high-accurate and stable inline testing to guarantee absolute measurement results under production conditions.

Highlights of Xelas INLINE-oled

Measurement of all OLED layers


  • Layer thickness 3nm-500nm
  • Spectral material properties n(λ)/k(λ) incl. data base of common materials
  • Surface roughness can be set
  • Reflectance and transmittance spectra taken with highest accuracy
Works under real process environments

  • Special design of both R- and T-head for highest value stability with respect to height and tilt tolerances in production
  • Inspection through glass windows: No affection of production during maintenance and service
  • Automatic internal calibration
  • Contactless and non-destructive
Proven for all relevant layers and stacks

  • Auto-triggering or I/O with the line
  • Monitoring of thicknesses in real-time, without disturbing the production process
  • Fast measurement speed


Xelas INLINE-oled



OLED layer thicknesses and n&k mappings