complete article as pdf file... - Dr. Schenk Inspection Systems

Newsletter March 2006
Fig.1a) ISM with Standard Acceleration Defect Channel
Fig.1b) ISM with ENHANCED ACC Channel making slightest
local deformations visible!
Conventional solutions only test selected radii, allowing acceleration
defects, located between the tested tracks, to remain
undetected. The Enhanced ACC Channel delivers incomparably
much more than a simple good/bad decision. It tests
the complete data area of each single disc with no exception,
providing detailed information on the defect type and size with
its exact position and together with a significant high-resolution
gray image. Despite the large measurement area, there is no
influence on the cycle time, as the test takes place simultaneously
during general disc inspection.
The Enhanced ACC Channel option is fully integrated into the
ISM in-line scanners. Now, for the first time, real-time process
feedback enables replicators to optimize the production process
based on acceleration defects. In addition, each type of local
deformation points to the associated process step, causing
that defect, e.g. a dimple indicates a problem during the bonding
process for DVD±R DL discs. The yield for high-speed discs
can be drastically enhanced by process issues being reported
and pinpointed immediately as they occur - on the straightforward
user interface or, optionally, by an acoustic signal.
No Acceleration Defect Remains Undetected!
An ideal complement to the indispensable in-line solution is
achieved by the HIGH-RES ACC option of the comprehensive
off-line measurement system PROmeteus MT-200. This
valuable option enables high-resolution measurement of local
deformations on the complete disc in just approx. 30 seconds!
a) b)
Fig.2) The disc map, showing local deformations, taken with
the MT-200 (a) optimally correlates with the ACC map
of Electrical Test Drives (b)
Compared to the in-line solution, the MT-200 provides far more
analytical tools for detailed analysis of the measured defect
information. The results can be displayed in multiple views,
e.g. as an accurate disc map with all details.
The HIGH-RES ACC option complements reliable process
control for the challenging high-speed disc production.
How was this Innovative Solution Achieved?
A sole software solution, if it were at all possible, would absorb
enormous computing time. The unique options from Dr. Schenk,
however, are based on the perfect synergy between an innovative
hardware solution and a specially developed algorithm.
This makes it possible to achieve results, which correlate
optimally with the FE and TE results of pick-up drives.
Fig.3) The Focus Error signals of Electrical Test Drives (a)
also optimally correlate with the signals of the
Enhanced ACC Channel of the ISM (b) and the HIGH-
RES ACC of the MT-200 (c).
These new options measure the acceleration topography of
the complete disc surface, which a pick-up head has to follow.
As result, the ISM in-line scanner delivers a detailed highresolution
gray image and the PROmeteus MT-200 optionally
delivers a gray image or a false color map in a 3-D picture.
Avoiding the use of mechanical pick-up heads, these optical
measurements can virtually be carried out at any speed, making
them applicable not only for today’s high-speed discs, but also
for the upcoming high density discs, like HD DVD and Blu-ray.
Proven in Mass Production
Developed in close cooperation with technology leaders, the
comprehensive in-line and off-line solution from Dr. Schenk is
already fully established and successfully running at leading
disc production sites. Those replicators noticeably improved
their production process, as well as their yield within a very
short period of time. Replicators will highly appreciate these
indispensable new options, resulting in increasingly profitable
high speed disc production.
Dr. Schenk GmbH • Industriemesstechnik • Einsteinstrasse 37 (Martinsried) • D-82152 Planegg • Germany
Phone: +49-89-85695-0 • Fax: +49-89-85695-200 • www.drschenk.com • info@drschenk.com
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