Sophistication’ is a rough indicator
of how complicated the calibration procedure
is for the chosen calibration technique.
The extent of Calibration Sophistication
is continuous, and can range from very simple
to very complex. It is divided into the
three areas Simple, Normal, and Advanced
for discussion purposes only.
Calibration would involve using one or two
discs to calibrate the measurement system,
using one or two calibration reference points
per parameter calibrated. For example, using
a Philips 5B3 for CD, or the Philips Signal
Discs, or similar discs, for DVD, and using
the same discs that are used for calibration
to check the calibration.
main advantages of Simple Calibration are
that is it easy and quick. The reference
files are very short and simple, and are
available from DaTARIUS. A complete calibration
for DVD can take as little as 15 minutes,
and CD is even quicker.
There are two
main disadvantages of Simple Calibration.
First, the Calibration Population Range
is small, and is limited to discs that are
close in process to the calibration discs.
In the example mentioned for CD, the Philips
5B3 disc was manufactured with a 9-second
cycle time, giving very flat-bottomed 3T
pits. There are virtually no currently produced
CDs that are manufactured in this way. Second,
the fact that the same discs that are used
to perform the calibration are also used
to perform the check means that the calibration
never fails. In other words, there really
is no check to the calibration accuracy
since, unless something is very wrong with
the system, the check values will always
read correctly at the calibration points,
though they may be off on other discs.
uses discs that are closer to production
discs, and more of them. These can be, for
example, the DaTARIUS Calibration Discs
that are supplied with the measurement systems.
is more complex than Simple Calibration,
in order to increase the Calibration Population
Range. This calibration takes longer to
perform, because more reference points are
measured to maximize the calibration accuracy
over a wider range of disc types. Also,
the calibration checkpoints are not the
same as the calibration points, so the calibration
check performs a real evaluation of the
quality of the calibration. The calibration
reference file is also more complicated,
but this reference file is provided by DaTARIUS
in the case of the DaTARIUS calibration
as the name implies, is for advanced users,
or actually any users - with the help of
the experts at DaTARIUS Customer Service!
As the chart shows, users can create reference
files, or modify existing reference files,
to either decrease or increase the Calibration
Population Range, or for any other special
purposes that they may have.
An example of
why users would want to decrease the population
range would be to ‘fine-tune’
their measuring systems for their processes.
In other words, in a situation in which
users have a well-defined process window,
they can use calibration discs that they
have manufactured themselves to make sure
that the measuring systems are very accurate
over the entire range of discs that they
produce, though that accuracy would fall
off if they measure discs from a different
An example of
why users would want to increase the population
range would be the case in which they receive
stampers from several different external
sources for replication. In this case, users
would want to create a calibration disc
set to represent the range of discs they
make, based on the various stampers they
use, to maximize their calibration accuracy
across this wide range of discs.
An example of
a special purpose would be the case in which
the user has occasional deliveries to a
customer who uses one particular measurement
system for incoming inspection. In this
case, users can create a calibration reference
file such that their measurements match
the measurements made at this particular
customer site. Regular calibration would
then be used for most of the production,
and be switched to the special calibration
with jobs for this particular customer.
As can be seen,
Measurement Systems from DaTARIUS have all
the flexibility necessary to create whatever
type of calibration that the customer desires.
Use either a simple or normal calibration
with no effort, or customize the calibration
regimen in nearly infinite combinations.
Calibration may be made as quickly and as
easily as needed. Alternatively create a
calibration routine that, while it may take
longer to complete, covers the exact range
of discs that need to be tested with superb