The innovative technology of „DTD” differentiates itself from the standard CD-R and DVD-R/+R media predominantly by the use of the recording layer materials. The metal-ceramic composite is immune to the environmental influences on the optical disc and hence safeguards the data from aging with time.
THE CURRENT PROBLEM OF DATA LOSS WITH OPTICAL MEDIACommonly used recording layer materials for CD-R/ DVD-R/+R media are organic substances from the group „cyanine“ and „phtalocyanine“. The disadvantages of the organic materials are the crystallic structure that absorbs humidity and the material properties change with time due to the impact of light.
In general, so the written records have a total of nine different lengths as well as the lands in between, also having nine different lengths, DVD-R/+R has extra 14T length.
Due to humidity, after writing data onto the organic recording layer, a change in crystalls´ size occurs. Consequently, it results in change of pit size to such extend that the reading drives lose their ability to recognize the size of each pit and so the disc becomes unreadable.
In addition, modifying organic recording layer to fit higher recording speeds resulted in increased light sensitivity, hence instability with time.
Moreover, it is necessary to mention the question of the reflection layer corrosion. There are multiple available media on the market such as CD-R or DVD-R „for archival use“ where most likely silver reflective layer is substituted by gold.
However by only removing the corrosion problem, the optical disc manufacturers do not further mention remaining use of standard organic dye materials for the recording layer.
The recording layers of common standard CD-R and DVD-R/+R media have all above mentioned shortcomings, therefore readibility issues occur within the time span of 2-10 years.
THE SOLUTION OF PERMANENT DATA STORAGEAbove mentioned facts have led to the development of DVD+R Data Tresor Disc optical disc based on metal-ceramic and semi-metal recording layer.
These anorganic materials were chosen according to their stable attributes which enable constant pit size of the recording layer in the long term, while avoiding the problem of corrosion of reflective layer.
Burned „pits” of the digital record create permanent record that cannot be erased nor rewritten, as opposed to RW (rewritable) technology.
„DTD” does not need data rotation on regular basis and so the initial higher costs of the purchase of the disc are soon returned.
In addition, storing data on ecologically friendly „DTD”, less waste material from data rotation or migration is caused and so the techno-logy saves not only environment but as well your time and money.
TECHNICAL DESCRIPTION OF THE MANUFACTURING PROCESS OF DTDFirst of all, the two substrates with 120mm diameter and 0,6mm thickness are produced from pure polycabonate resin by using fully electrical injection molding maschines /Netstal E-Jets/.
One of them, Layer 0, transfers „U” groove from nickel stamper. The second one, Layer1-dummy, helps to keep „DTD” flat and also covers recording area from scratch and other mechanical damage.
„U” groove runs in spirals going from center to outer edge of the disc, its shape and size are adjusted with 0,1nm tolerance based on long term evaluation. All along the parameters are being analysed through special measuring instrument called AFM/atomic force microscope/.
The main difference between standard DVD+R and DATA TRESOR DISC production is in the type of recording layer.
On standard DVD+R, an organic light-sensitive dye mixture is spin-coated on the substrate, while on „DTD” a group of evaluated metal-ceramic and semi-metal elements is sputtered by multicathode unit. These layers are chosen due to their resistance and immunity against light, UV radiation, humidity, magnetism and other atmospheric effects.
Each of the three individual layers has one basic characteristic function: protection, recording and reflection. Full coating is made gradualy in 9 cathodes, while reactive plasma sputtering of components and gas in vaccum conditions ensures thickness homogenity of the sputtered materials on the surface of "U" groove. This metallization process is controlled by sofisticated measuring tool called Elypsometer, that can measure a thickness with resolution of 0,01nm.
After that, metallized substrate is bonded together with L1-dummy, using specially developed adhesive material which is also protective against light, humidity and temperature.
The last step is optical control of each produced disc by final scanner. It distinguishes, devides and sorts passed pieces and failed rejects with respect to ECMA standards which dictates to look for the count of leaks in layers, plastic defects, flatness and other optical parameters.
UNIQUE DVD+R BASED ON METAL-CERAMIC RECORDING LAYERS