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Sunny outlook:
Thin-film photovoltaics
at grid parity costs.
S
wiss company Oerlikon Solar
owes its confidence not only to
the continued growth of renew-
able energy, but also to its new
TCO deposition system, a solution that it
believes the market has been waiting for.
TCO stands for “transparent conductive
oxide”. The deposition system applies
transparent, conductive zinc oxide layers
on large glass sheets in six process
chambers. These layers act as electri-
cal contacts in the finished photovoltaic
module. Before deposition, the glass is
heated from room temperature to 200 °C
in just 20 seconds. “The art is in creating
an even temperature on the entire surface
of the glass. This allows us to deposit
homogeneous layers,” explains Clauss.
Gentle movement
The sheets of glass to be coated are
transported to the process chambers on
rollers. A pneumatic cylinder from Festo
moves small metal pins, which raise the
glass to various heights for deposition.
The servopneumatic proportional valve
MPYE controls all of the cylinders of
the chambers, regulates the speed and
approaches the various positions gently.
The pneumatic cylinder is a temperature-
resistant special design based on the
compact cylinder ADN.
Impressive lift
When the deposition process is com-
pleted, the glass moves to the exit lock.
It is then returned from the vacuum back
into the atmosphere. An automated lift
moves the sheets to the next process
step. The lift incorporates pneumatic
axes DGC from Festo, while the axis ELGR
ensures constant speed. “The Festo
products used helped us to keep the
system costs down,” explains Clauss.
“A converter with electric motor would
have been far more expensive.”
1.2012
trends in automation
Synergies
32 – 33