AN IMPROVED CDR/DVDR MANUFACTURING METHOD INCLUDING AN
IMPROVED SPUTTERING TECHNIQUE
FIELD OF THE INVENTION
The present invention, in general, relates to an improved CDR/DVDR
manufacturing method, including an improved sputtering technique and in
particular, to application of an improved sputter target, during sputtering
operation which is economically significant.
BACKGROUND OF THE INVENTION
It is well known in the art of CDR/DVDR manufacturing process, that the three
principal steps involved are dye coating, sputtering and lacquering and/or UV
curing. Now, the required single or multiple layers of coating, is/are deposited on
the disc surface, by sputtering process. So, sputtering constitutes an important
component in CDR/DVDR manufacturing process. Furthermore, two critical
parameters, which are required to be observed, in the art are as follows:
(i)Reflectivity > 60%,
(ii)Disc stability test at 55 degree / 50 % Rh / 96 hours. To ensure the above, the sputtering target, applied during the sputtering process, is usually made of silver or gold. However, this results in substantial increase in the cost of production and consequently, increase in the cost of the final product. To bring down the production cost reasonably, efforts are on over the years for developing a sputter target which is less costly and simultaneously, ensures maintenance of the parameters as aforesaid. However, it has been observed, that any other composition, when used, results in violation of the aforesaid parameters.
Accordingly, there was a long felt need to develop a composition for sputter target, for application during sputtering operation, which is substantially less expensive and simultaneously ensures maintenance of the requisite parameters.

The present invention meets the aforesaid long felt need. This invention is
applicable in various fields, such as in the area of optical media, but is not limited
to it and is also applicable in other related fields, as may be clear to persons
skilled in the art,
OBJECTS OF THE INVENTION
It is a principal object of the present invention, to provide an improved
CDR/DVDR manufacturing method, which includes an improved sputtering
technique.
It is a further object of the present invention to provide an improved sputtering
technique, which includes a sputter target which is reasonably less costly.
It is a further object of the present invention, to reduce the cost of production of
CDR/DVDR to a reasonable extent, by utilization of a sputter target which is
reasonably less costly and yet meets the basic technical parameters, required to
be maintained in the process.
Finally, it is a very important object of the present invention to provide CDRs/
DVDRs at reasonable cost.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides an improved method for
manufacturing CDR/DVDR including dyeing, sputtering and lacquering and/or UV
curing, said process for sputtering involving generating layer(s) of reflective
coating on discs, wherein said sputtering is done by means of a sputter target
made of optimally effective proportions of at least copper and zinc, whereby the
cost of production of CDR/DVDR is reduced to a reasonable extent and
simultaneously, the technical effectiveness of the sputter target is maintained.
In accordance with preferred embodiments of the present invention:
-said sputter target comprises optimally effective proportions of copper, zinc and
nickel.
-the CDR/DVDR so manufactured has the following properties (i)ReflectivJty >
60%, (ii) Disc stability test at 55 degree / 50 % Rh / 96 hours.

The present invention also provides an improved sputtering method for its application in DVDR manufacturing process, said sputtering method involving, generating layer(s) of reflective coating on discs, wherein said sputtering is done by means of a sputter target made of optimally effective proportions of at least copper and zinc, whereby the cost of production of CDR/DVDR is reduced to a reasonable extent and simultaneously, the technical effectiveness of the sputter target is maintained.
The present invention also includes CDRs/DVDRs manufactured by the method as described hereinbefore.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The nature and scope of the present invention will be better understood from the accompanying drawings, which illustrates preferred embodiments of the method in accordance with the invention. The drawings are meant for illustration and understanding of the present invention and not for any sort of limitation. In the accompanying drawings,
Fig 1 illustrates a CDR manufacturing process, applying the improved sputtering target in accordance with the present invention. Fig 2 illustrates a DVDR manufacturing process, applying the improved sputtering target in accordance with the present invention. BRIEF DESCRIPTION OF THE INVENTION
It is traditionally known that the three principal steps involved in CDR/DVDR manufacturing process involves dyeing, sputtering and lacquering and/or UV curing. The required single or multiple layers of coating, is/are deposited on the disc surface by sputtering process. So, sputtering constitutes an important component in CDR/DVDR manufacturing process. Furthermore, two critical parameters, which are required to be observed, in the art are as follows:
(i)Reflectivity > 60%,
(ii) Disc stability test at 55 degree / 50 % Rh / 96 hours.

To ensure the above, the sputtering target, applied during the sputtering process, is usually made of silver or gold. However, this results in substantial increase in the cost of production and consequently, increase in the cost of the final product
The present invention provides an improved sputter target which comprises optimally effective proportions of at least copper and zinc, rather than gold/silver and yet maintains technical effectiveness of the sputter target. The sputter target, in accordance with the invention may be made of optimally effective proportions of copper, zinc and nickel as well.
Applying the sputter target, in accordance with the present invention results, in substantial reduction in the cost of production and consequently, in substantial reduction in the cost of the final product. So, the present invention has tremendous economic significance, which was hitherto not achieved. Furthermore, the layer(s) of reflective coating on discs, generated by the sputtering technique in accordance with the invention, is technically sound as well. Additionally, it also ensures the golden luster, provided by the hitherto known gold/silver sputter target.
Figures 1 and 2 in detail, illustrate, exactly where the sputter target in accordance with the present invention is applied in CDRDVDR manufacturing process. As it will be clear from the two figures, in CDR/DVDR manufacturing process, sputtering is an important component, immediately after first optical inspection, so that the reflective coating, formed on the disc surface, is appropriate. Hitherto, a less costly, yet equally technically effective replacement for the existing, gold/silver sputter target could not be deciphered. The present invention has been successful in that respect, after extensive research and trial, by providing a sputter target, comprising optimally effective proportions of copper and zinc as well as optimally effective proportions of copper, zinc and nickel,

The present invention has been described with reference to some drawings and preferred embodiments, purely for the sake of understanding and not by way of any limitation and the present invention includes all legitimate developments within the scope of what has been described hereinbefore and what has been claimed hereinafter.

WE CLAIM
1. An improved method for manufacturing CDR/DVDR including dyeing, sputtering and lacquering and/or UV curing, said process for sputtering involving generating layer(s) of reflective coating on discs, wherein said sputtering is done by means of a sputter target made of optimally effective proportions of at least copper and zinc, whereby the cost of production of CDR/DVDR is reduced to a reasonable extent and simultaneously, the technical effectiveness of the sputter target is maintained.
2. The improved method for manufacturing CDR/DVDR as claimed in claim 1 wherein said sputter target comprises optimally effective proportions of copper, zinc and nickel.
3. An improved method for manufacturing CDR/DVDR, as claimed in any of claims 1 or 2, wherein, the CDR/DVDR so manufactured has the following properties (i)Reflectivity > 60%, (ii) Disc stability test at 55 degree / 50 % Rh / 96 hours.
4. An improved sputtering method for its application in DVDR manufacturing process, said sputtering method involving, generating layer(s) of reflective coating on discs, wherein said sputtering is done by means of a sputter target made of optimally effective proportions of at least copper and zinc, whereby the cost of production of CDR/DVDR is reduced to a reasonable extent and simultaneously, the technical effectiveness of the sputter target is maintained.

5. The improved sputtering method for its application in DVDR manufacturing process, wherein said sputter target comprises optimally effective proportions of copper, zinc and nickel. 6 CDRs/DVDRs manufactured by the method as claimed in any preceding claim.