Inline systems and offline equipment for both production control and development of OLED layers and stacks.

Experience and Knowledge

Thin film coatings for organic light-emitting diodes (OLED) are made of many different materials, such as Indium-Tin-Oxide (ITO) or organic layers, ranging in thickness from approx. 3 nm to 500 nm. Small molecule and polymer technology is currently used in OLED production.

nxt has developed a product group to check both inline and offline all types of layers which are currently used for any type of OLED stack, including organic and inorganic layers.

Based on 15 years experience in thin-film testing, special optical components have been designed to guarantee highest precision of the spectral reflectance/transmittance which are needed for precise, reliable and fast testing of layer thickness and n&k.

Principle of Measurement

Phase differences between the front and rear side reflection of thin layers cause interference, absorption inside each layer changes light wave amplitude. Both of these phenomenona can be used together to measure the layer thickness and refractive and absorption index n&k of thin layers. After recording the spectra a mathematical calculation is performed in which the layer thicknesses and the parameters for the optical properties n&k are varied until model and measurement match perfectly.



OLED layer thicknesses and n&k mappings



Thicknesses of organic and ITO layers