AN IMPROVED DVDR MANUFACTURING SYSTEM AND AN IMPROVED METHOD FOR MANUFACTURING DVDRS.
Field of the Invention
The present invention, in general, relates to an improved DVDR manufacturing system and to an improved method for manufacturing DVDRs and in particular to an improved center pin for performing resin spinning process on bonder of optical media manufacturing lines and in particular, to an improved method for resin spinning, involved in DVDR process, which minimize chances of disc separation during handling and avoid resin bubble formations.
BACKGROUND OF THE INVENTION
Traditionally, a DVDR manufacturing process, involves the three principal steps of dye coating, sputtering and bonding.
In DVDR manufacturing processes known in the art, bonding involves, joining of Active and Dummy, with the help of Resin. Resin dispenses at bonding chuck between two discs (Active & Dummy), through a needle. Thereafter, capillary action takes place and resin is spread all over the disc. Then the disc go for spinning. After spinning, disc is picked from spin cup and placed at the UV Area, which is the most typical process in bonding. Due to improper picking and placing, precisely due to improper clearance between pin and disc, resin bubble is generated, which accounts for almost rejection of 1.5% of the yield. Furthermore, original center pins on spinner cups in bonder, meant for picking and placing discs after spinning, have narrow margin to accommodate gripper fingers of handler, while picking disc from Spinner Cup. This marginality in pin design, coupled with misalignment of handler/gripper fingers, result in spin cup gripper life deterioration, through time due to high Impact on cylinder of gripper and bend or damage Gripper Pin. These, consequently increase the cost of production as well.
Attempts have been made over the years, to sort out this problem, but significant improvement was not achieved.
Accordingly, there was a long felt need to develop a manufacturing system and a method for DVDRs wherein the bonding process is improved such that, rejection due to bubble formation is minimized to a reasonable extent.
The DVDR manufacturing system and method in accordance with the present invention aims at meeting this long felt need.

All through out the specification including the claims, reference has been made to DVDRs for the sake of understanding, but is not to limited to it and the present invention embraces all similar items in the field, as may be understood by persons skilled in the art.
OBJECTS OF THE INVENTION
It is a principal object of the present invention to develop a manufacturing system for DVDRs which minimizes rejection of discs due to bubble formation during bonding process.
It is a further object of the present invention to provide a method for manufacturing DVDRs including an improved bonding process which minimizes rejection of discs due to bubble formation.
It is a further object of the present invention, to provide an improved method for bonding, involved in the process of manufacturing DVDRs, which utilizes a specially designed center pin, whereby rejection of discs due to bubble formation, resulting from improper picking and placing of discs is minimized.
It is a further object of the present invention, to provide an improved method for bonding, involved in the process of manufacturing DVDRs, which utilizes a specially designed center pin, whereby rejection of discs, due to problem in clearance between pin and disc is minimized.
It is yet another object of the present invention to provide an improved method for manufacturing DVDRS which reduces the overall cost of production and consequently, the overall cost of DVDRS.
It is a further object of the present invention to provide a method for reducing bubble formation and consequently rejection of DVDRs, during the bonding process, involved in manufacturing DVDRs.
It is a further object of the present invention to provide an improved method for manufacturing DVDRs, which involves an improved bonding process, whereby spin cup gripper life deterioration due to high Impact on cylinder of gripper and bend or damage of gripper pin is reduced..
It is a further object of the present invention to provide an improved DVDR obtained by the improved manufacturing system as stated aforesaid.
The foregoing objects and the other aspects of the present invention will be clear from the following description which is purely by way of understanding and not by way of any sort of limitation.

SUMMARY OF THE INVENTION
The present invention provides an improved DVDR manufacturing system including means for dyeing, sputtering and bonding wherein said means for bonding has an improved central spin pin for picking and placing of discs after spinning process , configuration of said pin being modified for easier and smooth ejection of the discs during transfer, thereby ensuring minimization of chances of disc separation, during handling and avoiding resin bubble formation.
In accordance with preferred embodiments of the DVDR manufacturing system of the present invention;
-said means for bonding includes gripper or handler alignment.
-height and slope of said pin is modified.
-increased gap, between lobes on the center pin, provides higher margin for gripper fingers and thus prevent their damage.
The present invention also provides an improved method for manufacturing DVDR including dyeing, sputtering and bonding, said process for bonding involving, joining of active and dummy discs, with the help of resin, dispensing resin at bonding chuck between the two discs (Active & Dummy) , through a needle, initiation of capillary action, spreading of resin all over the disc, followed by spinning, picking of discs from spin cup and placing at the UV Area, wherein modification of configuration of the central spin pin meant for picking and placing discs, is carried out, for easier and smooth ejection of the discs during transfer, thereby ensuring minimization of chances of disc separation, during handling and avoiding resin bubble formation.
In accordance with preferred embodiments of the method for manufacturing DVDR of the present invention:
-said bonding process includes gripper or handler alignment for picking and placing of discs.
-said modification of central pin comprises adjustment of height and slope.
-gap between lobes on the central pin is increased, thereby providing higher margin for gripper fingers and thus preventing their damage.
The present invention also provides a method for reducing spin cup gripper life deterioration due to high Impact on cylinder of gripper and bend or damage of gripper pin comprising applying the method as described herein above.

The present invention also provides a DVDR produced 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 are by way of illustration of some preferred embodiments and not by way of any sort of limitation.
Fig 1 illustrates a conventional central pin utilized in bonding processes known in the art.
Fig 2 illustrates a close view of the gap, between the pin and the disc, according to the conventional arrangement.
Fig 3 illustrates the gap between the disc and the pin after spinning, according to the conventional arrangement.
Fig 4 illustrates the gap between the disc and the pin after lifting according to the conventional arrangement.
Fig 5 illustrates the forces on disc which creates gap between the active disc and the dummy disc.
Fig 6 illustrates sliding between both active and dummy disc.
Fig 7 illustrates a modified design of the center pin, in accordance with the present invention.
Figs 8 and 9 illustrates enlarged views of the center pin in accordance with the present invention.
Fig 10 illustrates an exploded view of the center pin, in accordance with the present invention.
BRIEF DESCRIPTION OF THE INVENTION
The following describes some preferred embodiments of the present invention, which are purely for the sake of understanding the performance of the invention, and not by way of any sort of limitation.
As stated aforesaid the manufacturing process of DVDRs involves the three principal steps of dye coating, sputtering and bonding. The process of bonding involves, joining of Active and Dummy, with the help of Resin. Resin dispenses at bonding chuck between two discs (Active & Dummy), through a needle.

Thereafter, capillary action takes place and resin is spread all over the disc. Then the disc go for spinning. After spinning, disc is picked from spin cup and placed at the UV Area, which is the most typical process in bonding. Due to improper picking and placing, precisely due to improper clearance between pin and disc, resin bubble is generated, which accounts for almost rejection of 1.5% of the yield. This consequently increases the cost of production as well. Attempts have been made over the years, to sort out this problem, but significant improvement was not achieved. The present invention aims, at minimizing the rejection of discs, phmarily due to bubble formation. Now, original center Pins on spinner cups in bonder have narrow margin to accommodate gripper fingers of handler while picking disc from spinner cup. This marginality in pin design, coupled with misalignment of handler/gripper fingers, result in spin cup gripper life deterioration day by day due to high Impact on cylinder of gripper and bend or damage gripper pin. Repeat damages to gripper fingers/ cylinders, from the existing design of center pin, result in separation of bonded discs, creating bubbles at the clamping area.


From Fig 2, it is clear that the gap between disc and spin cup pin is near about 0.5-0.75 mm and when the bend handler or faulty gripper picks the disc, the disc starts bending towards its forcible direction in spite of being parallel. Fig 3, illustrates the gap between the disc and the pin after spinning, according to the conventional arrangement.
From Fig 4, when the disc starts lifting, gap between spin cup pin and disc is almost zero. Disc starts rubbing on the pin and at the time of rubbing two motions occur. Fig 5 illustrates forces on disc, due to which gap occurs between both discs active and dummy. Fig 6 illustrates sliding between both discs active and dummy.
It has been deciphered through extensive research that the problem is basically from spin cup Pin because of its abnormal length. Furthermore, problem crops up if the spin cup pin length is decreased , say to 3.8 mm.
The modified design of Center Pin, as illustrated in Fig 7, accommodates gripper finger insertion with a larger margin, thereby reducing bubble formation, by around 75%.
To solve the problems, as discussed aforesaid, the height and slope of pin have been modified. The top portion, allows easier and smooth ejection of the disc during transfer, even when the gripper condition deteriorates due to normal wear. Increased gap, between lobes on the center pin, provides higher margin for gripper fingers and thus prevent their damage. Both of the above improvements minimize chances of disc separation, during handling and avoid resin bubble.
The above aspects will be clear from Figs 8 and 9 which illustrate enlarged views of the center pin in accordance with the present invention. The above will also be clear from Fig 10, which illustrates an exploded view of the center pin, in accordance with the present invention.
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 DVDR manufacturing system including means for dyeing,
sputtering and bonding wherein said means for bonding has an improved central
spin pin for picking and placing of discs after spinning process, configuration of
said pin being modified for easier and smooth ejection of the discs during
transfer, thereby ensuring minimization of chances of disc separation, during
handling and avoiding resin bubble formation.
2. The improved DVDR manufacturing system as claimed in claim 1 wherein said means for bonding includes gripper or handler alignment.
3. The improved DVDR manufacturing system as claimed in any of claims 1 or 2 wherein height and slope of said pin is modified.
4. The improved DVDR manufacturing system as claimed in any preceding claim
wherein increased gap, between lobes on the center pin, provides higher margin
for gripper fingers and thus prevents their damage.
5An improved method for manufacturing DVDR including dyeing, sputtering and bonding, said process for bonding involving, joining of active and dummy discs, with the help of resin, dispensing resin at bonding chuck between the two discs (Active & Dummy through a needle, initiation of capillary action, spreading of resin all over the disc, followed by spinning, picking of discs from spin cup and placing at the UV Area, wherein modification of configuration of the central spin pin meant for picking and placing discs is carried out, for easier and smooth ejection of the discs during transfer, thereby ensuring minimization of chances of disc separation, during handling and avoiding resin bubble formation.
6. The improved method for manufacturing DVDR as claimed in claim 5, wherein said bonding process includes gripper or handler alignment for picking and placing of discs.
7. The improved method for manufacturing DVDR as claimed in claim 5 or 6, wherein said modification of central pin comprises adjustment of height and slope.
8. The improved method for manufacturing DVDR as claimed in claims 5 to 7 wherein gap between lobes on the central pin is increased, thereby providing higher margin for gripper fingers and thus preventing their damage.

9. A method for reducing spin cup gripper life deterioration due to high Impact
on cylinder of gripper and bend or damage of gripper pin, comprising applying
the method as claimed in claims 5 to 8.
10. A DVDR produced by the method as claimed in claims 5 to 9.