Design of the magnetic field and the
calculation of electromagnetic equipment is decisive for the
effectiveness of the magnetic flip fixture. The electromagnets need
special features for a proper operation of the magnetic flip fixture.
They can be prepared for installation inside or outside of the vacuum
chamber. The special configuration of the magnets concentrates and
directs the magnetic field to where it is needed.
The design of the lens holder allows a
rotation around its rotational axis and at the same time ensures a
stable bedding during the deposition process. The magnetizable holder
can easily be mounted into the bearing supports on the dome. Its
material suits vacuum coating demands as well as cleaning standards.
The design can be adjusted to fit the needs for holding ophthalmic
lenses or other objects, for example wafers.
Q: Do objects fall out of the object holders when they are turned?
A: Spring rings are well established as holders of plastic lenses for
vacuum coating. The risk for lenses to fall out of the lens holders is
not greater than for regular spring rings. Also, holders without
springs can be used for other objects.
Q: Does the magnetic field effect the coating process?
A: No. The electromagnets are only switched on for the flip procedure,
between two coating runs. The remanence of the magnetizable parts is
limited by the type of material that is chosen. For common materials it
is much too small to have an effect on the operation of an electron gun
or an ion treatment.