is the accuracy with which zero-motion can be sustained over time, or the ability
of a system to resume its state after being displaced. When qualifying the stability
characteristic of the any
there are three major components that must be taken into consideration: temperature
sensitivity, sensitivity to external forces and sensitivity to actuator drift. The
have been meticulously engineered for high stability in these major areas and can
easily outperform any stage currently on the market.
The athermalized design of Luminos
allows them to effectively react to temperature changes as if each were a single
piece of aluminum. Luminos
are axially symmetrical and all components are thermally matched with aluminum.
This ensures that they have the same co-efficient of thermal expansion (CTE). Since
all parts are symmetric and matched with aluminum any adverse effects of thermal
expansion are nullified. The Luminos
have been tested to show no hysteresis due to temperature changes. Environmental
testing illustrate variation has been characterized as highly repeatable. When they
are subjected to a series of thermal cycles the variation is highly repeatable and
cyclic. There is virtually no distortion of components and temperature fluctuations
have no detrimental effect on the stability.
Conventional flexure stages have extreme responses to everyday vibrational frequencies.
Ordinary activities such as someone walking across a lab floor can cause serious
effects. Usually extreme measures are employed to achieve a protective environment.
The aggressive modifications employ expensive and sometimes impractical filtering
agents such as optical tables, special flooring, isolations chambers etc. However,
are so stable that shifts due to everyday vibration are not a factor. Luminos' approach
to this problem was to design a damping system directly into each
Also all CORALIGN™ units have a protective exterior
shell. This shell is designed to shunt any operator induced vibrations away from
the sensitive moving parts. Furthermore, an internal damping structure dissipates
any external vibrational forces that may attempt to reach the flexure element. The
internal damping coupled with a stiff exterior shell also provides high stiffness
making for an extremely stable
Actuator / Micrometer
All drive mechanisms, micrometers, actuators etc. are vulnerable to drift. Grease
between threads, lead nuts and other composite materials causes the threads to migrate
when exposed to temperature changes and vibrations. With Luminos CORALIGN™
the patented Ratio Drive™ System diminishes
drift by leveraging the input to drive the output. Ratio Drive™ also diminishes drift contributed by the actuators. If a non-Luminos
positioning unit experiences 1µm of drift from the drive mechanisms, the result
will be an output drift of 1µm. However, for a Luminos 25x Ratio Drive™
a drift of 1um would be divided down by a ratio of 25:1 resulting in only a 0.04µm
output deviation. Thus Ratio Drive™ further
improves the stability of the Luminos' CORALIGN™
Stability Test Results
stability characteristic is fundamental when planning an application. The Luminos
systems have been carefully characterized and the results are striking. The test
result below show how stable these systems are.