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Point sensors uses highly precise stages to create
profiles and 3D topographies. The sample, which is placed under the sensor, is
moved by the stages while the sensor transmits the height data to the
measurement control unit. To improve lateral accuracy, the sensors are
synchronized to the stage movement. This method also avoids inaccuracies caused
by acceleration and deceleration of the stages.
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ST Instruments point sensor systems come
with one or multiple sensors, depending on the specific application
and needs:
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Point
sensor systems distinguish themselves through their flexibility and ability
to be easily automated. Therefore, they can be found in R&D as well as
production environments.
As opposed to stylus profilers, it's
non-contact and for that reason non-destructive. They also have a higher
measurement speed, which makes them ideal for production environments. The
accuracy of the profilometers is verified by in-house
calibration and testing procedures with certified standards.
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| Laser
Triangulation gauge |
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technique used for the laser triangulation gauge deduces the height of a
surface point by sensing the position of a laser spot on the surface using
a detector placed at a certain angle away from the incoming laser beam. |
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Conventional
laser displacement sensors employ a PSD (position sensitive detector) as
the light-receiving element. However, the LK series uses a CCD as the
light-receiving element. The light reflected by a target passes through
the receiver lens and is focused on the PSD or CCD. The PSD uses the light
quantity distribution of the entire beam spot entering the light element
to determine the beam spot center and identifies this as the target
position. However,
the distribution of light quantity is affected by the surface conditions
of the target, causing variations in measured values. The CCD detects the
peak value of the light quantity distribution of the beam spot for each
pixel and identifies this a s the target position. Therefore, the CCD
enables stable highly accurate displacement measurement, regardless of the
light quantity distribution of the beam spot. |
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Nobis®
chromatic confocal optical distance gauges
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technique used for the Chromatic confocal Nobis gauge deduces the surface height of
a feature by using an aberration technique which focuses the different
elements of white light at different heights.
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white light beam is focused on a surface through a lens with chromatic
length aberration. Due to this aberration, the focus point is at a
different Z-position for different wavelengths. The reflected light is
sent to a spectrometer through a pin hole. The spectrometer provides an
intensity curve depending on the wavelength. The focused wavelength is the
one corresponding to the maximum of intensity. |
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use of monochromatic wavelengths to discern Z height eliminates the need
for moving components in the sensor resulting in a robust extremely
accurate solution. |
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Inductive
contact gauge |
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In some
applications contact measurement may actually be preferred because a
direct representation of the surface can be derived. In many such
instances the physical effects of stylus force are negligible or at
least well understood. Some types of surfaces cannot be measured by
stylus. Contact with a stylus may cause damage to soft, flexible or
otherwise sensitive components; in some cases stylus force may deform a
feature. Optical gauges solve those problems and, in most cases, offer
much higher inspection speeds as well
The
HP-series reflects this reality by offering dual contact and non-contact
gauge configurations and a top of the line multi-gauge configuration.
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