GONIOMATIC
The Automatic Prism Measuring Instrument
GONIOMATIC is an automated Goniometer with motorized specimen table and electronic image evaluation.
GONIOMATIC serves for the accurate absolute angle measurement of all kind of prisms.
GONIOMATIC corresponds to a classical manual goniometer and fulfills its measuring functions, but it is much more easier in operation.
The GONIOMATIC
is a really automatic goniometer featuring accurate measurements of prism angles
from 0° to 360° in reflection. It incorporates most modern technologies like a
highly resolution image processing system, a
precision
turntable, a stepping motor controller
with
micro step-by-step operation and an incremental rotation
encoder
with high
angle resolution.
Since the GONIOMATIC is using a computerised autocollimator, no precise, difficult and time consuming alignment procedures are necessary. The tilt table is simply rotated until the autocollimator is approximately in autocollimation position to the first surface of the prism or polygon. To achieve this, the operator is rotating the table until the reflected image of the autocollimator appears on the PC-monitor within a defined range area. The same procedure is repeated to obtain a reading from the second surface of the prism. The tiresome and difficult visual alignment becomes obsolete.
This is not
only incomparably easier and comfortable for the operator, but very important
for the overall accuracy of the instrument. In other goniometers the
overall accuracy - even when using an accurate
encoder - is decisively limited by the ability of
the operator to visually and repeatedly
align the autocollimator perfectly square to the sample surface. This ability is normally limited at +/-
one crossline thickness. Taking for example an autocollimator with focal length
of 300 mm and a crossline thickness of
10µm, the angular error corresponding to
10µm is 3.5 arcsec. Certainly this error can be reduced repeating the
measurement
several times and calculating the main value, however, this is inefficient and
dependent on the ability
and the degree of tiredness of the operator.
Setup
Technical parameters
|
GONIOMATIC |
Parameter |
|
GONIOMATIC with incremental rotation encoder |
|
|
Measuring range |
0° ... 360° |
|
resolution |
0,5“ |
|
accuracy* |
+/- 2,5“ (arcsec) |
|
measuring mode |
in reflection |
|
Master |
not necessary |
* 95% of all measuring values are inside specification for a
standard specimen