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Research Area

Primer & Chemical Surface Treatment

Research Area

Primer & Chemical Surface Treatment

VUV Systems

VUV refers to a particularly short-wave part of the UVC spectrum. Our research is primarily focused on the development of practical process solutions using short-wave UVC light for surface treatment and exploring potential fields of application.
A versatile and uncomplicated convertible testing technique was developed, which can be operated with different light sources and optionally as a closed chamber or as an open unit in continuous throughput process. Treatment parameters, which are relevant for manufacturing, can be varied and reproducibly adjusted. The VUV treatment can be performed under air ambient conditions or by adding other process gases such as inert gas, nitrogen or precursor formulations.
For developing and testing of new methods as well as for the further development of these methods for new applications, various UVC light sources with different emission wavelengths are available:

Xe Excimer (172 nm)

Xe Excimer

Manufacturer:Osram/Ledvance
Model:XIS 375x96
VUV conveyor system (infeed side) with the excimer lamp, followed by the Hg irradiation unit
VUV conveyor system (infeed side)

The operating principle of the Excimer – excited dimer, is the excitation of a metastable state to form a noble gas molecule during whose disintegration light of a specific wavelength is emitted.
Our system works with xenon as the operation gas. With emitted wavelength of 172 nm, almost all organic substances can be cracked, which makes this irradiation system interesting for many surface cleaning and activation applications.

The treatment of PE samples with xenon excimer radiation using conveyor equipment is shown.
Continuous treatment of PE samples with xenon excimer radiation

Application Examples   

172 nm xenon excimer (close-up view) and reactor with precursor gas supply are shown.
172 nm xenon excimer (close-up view) and reactor with precursor gas supply

Device Configuration    

  • Power input: max. 330 Watt
  • Irradiation power: adjustable up to max. 40 mW/cm²
  • Height adjustment: 0 to 100 mm
  • Irradiation width: max. 38 cm
  • Stationary and conveyor operation possible
  • Conveyor speed: 5 to 200 cm/min
Low Pressure Hg Lamp System (185 & 254 nm)

Low Pressure Hg Lamp System

Manufacturer:Groebel UV
Model:custom-built fabrication
VUV conveyor system (output side) with view of Hg irradiation unit
VUV conveyor system (output side)

The low pressure mercury amalgam lamps installed in our irradiation system emit a spectrum with two main lines at 185 and 245 nm. At wavelengths below 200 nm, light can transform oxygen into ozone.
In combination with the emitted irradiation, these reactive oxygen species are able to clean surfaces of polymers and break bonds in polymer molecules. In contrast to the 172 nm excimer unit, the working distance can be varied more freely, which also allows the treatment of non-planar sample structures.

The stationary irradiation chamber with mercury lamps and test specimens are shown.
Stationary irradiation chamber with mercury lamps

Application Examples

The figure shows Organic sheets (GRP plates) during the passage through the mercury irradiation unit.
Organic sheets (GRP plates) during the passage through the mercury irradiation unit
The picture shows reactor, which is intended for treatments under protective or active gas, on the conveyor through the mercury irradiation unit.
Reactor (for treatments under protective or active gas), on the conveyor through the mercury irradiation unit

Device Configuration   

  • Operation settings:
    • Power input: 385 W
    • Lamps: 11; separately switchable
    • Maximum intensity: at 185 nm → 8 mW/cm²
    • Maximum intensity: at 254 nm → 50 mW/cm²
  • Irradiation width: max. 38 cm
  • Irradiation distance: adjustable to 16 cm
  • Stationary and conveyor operation possible
  • Conveyor speed: 5 to 200 cm/min
Excimer (193 nm)

Excimer Laser

Manufacturer:ATL/Optec
Model:custom-built fabrication
A pictureof the 193 nm ArF laser (front view of the system) with computer control and working chamber is shown.
193 nm ArF laser (front view of the system)

In contrast to the UVC lamps available in our house, this excimer laser emits coherent light with a single defined, narrow banded wavelength.
The used laser is a pulsed argon fluoride (ArF) laser manufactured by ATL. It can be operated with variable pulse frequency and has three switchable optical systems, which allows setting for a wide fluence range. With this system, our in-house facilities for treatment technical surfaces with VUV irradiation are optimally supplemented.

193 nm ArF laser (side view)
193 nm ArF laser (side view)

Application Examples  

193 nm ArF laser (inside view with xy stage, gas flushing and suction)
193 nm ArF laser (inside)
The interior view of the working chamber with xy stage, gas flushing and suction of the 193 nm ArF laser is illustrated.
193 nm ArF laser (interior view of the working chamber with xy stage, gas flushing and suction)

Device Configuration   

  • Operation settings:
    • Frequency: 1 - 500 Hz
    • Pulse energy: 3 - 10 mJ
    • Adjustable fluence: 3 - 160 mJ/cm² (single pulse)
  • 3 switchable optical systems
  • Motorized x-y stage for irradiation of areas up to approx. 30 × 20 cm²
  • Software-assisted irradiation for precise setting of fluence with high spatially resolution

further Proceedings of our Irradiation Technology

The picutre shows the laser cleaning of rusty steel to demonstrate the effectiveness of the cleaning process.
Infrared Laser (Solid-state laser)
Infrared-Laser (CO2-Laser)

Dr. Joerg Leuthaeusser

Head of Department
Primer and Chemical Surface Treatment

e-mail
Phone: +49 3641 2825 48