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Optical Metrology |
Precision Measurement
Examples of DIVERSE experience in non-contact precision measurement systems
Real-Time Holographic Interferometer
Development of a real-time holographic interferometer
consisting of a high power Argon-ion laser, Gaussian filter,
beam expander, beam splitter, steering mirrors, holographic
diffuser and a mount for the volume hologram. The
instrumentation allowed the operator to create a hologram of
a finite volume, then disturb that region with a high
velocity object and produce a holographic interferogram
which was recorded by a multiple image high speed camera.
Monitoring printhead inkjet nozzles
Optical techniques used to monitor jet alignment,
stability, breakup height of ink droplets and optimum print
windows for a particular nozzle. For the alignment criteria
the jet is detected inside the proscribed range along two
orthogonal axes of the plane perpendicular to the
nozzle-gutter axis. The minimum width of the inkjets
examined is 0.06 mm and the position detected on either axis
within a range of 4.5 mm at a resolution of 15 microns.
Printhead positioning system
In continuous ink jet printing the head must be positioned
at a safe distance from the product moving past. The product
is irregular in shape and motion so the printhead
positioning must be controlled to permit the smallest
possible throw distance for high resolution without physical
contact with the product. The printhead positioning system
involved a position detector measuring the printhead to
object distance with linear actuation in one plane.
Non-contact triangulation probe
Based on the triangulation principal a probe with a visible
laser diode source and a position sensitive detector was
developed to provide a non-contact means for monitoring the
position of machined surfaces. Compromises had to be found
between range, stand-off and resolution so that a high
repeatability could be achieved whilst operating at a
practical distance from the test piece.
Smoke cell vision test unit
This instrument (pictured above) accurately measures a precision optical
assembly comprising two off-axis parabolic reflectors and a single collection
optic used in a smoke detector. The optical components are created within
a plastic injection moulding using a two part process. Inspection utilised
a precise light source which was reimaged by the optical system onto a
diffuse screen. An image of the screen was captured by a CCD camera and
the image analysed to determine that the physical location of the spot
and the aberrations are within tolerance.
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