AN IMPROVED MANUFACTURING SYSTEM FOR OPTICAL MEDIA AND AN IMPROVED METHOD FOR MANUFACTURING OPTICAL MEDIA

FIELD OF THE INVENTION

The present invention, in general, relates to an improved manufacturing system for optical media and to an improved method for manufacturing optical media and in particular, to applying at least a dummy disc devoid of moat area and having a suitable optimum inner diameter, whereby, chances of rejection due to resin bubble formations and other bonding related problems, are minimized.

BACKGROUND OF THE INVENTION

Traditionally, manufacturing process for optical media such as but not limited to DVDRS, involves the three principal steps of dye coating, sputtering and bonding. In such manufacturing processes known in the art, bonding involves, joining of active and dummy discs, with the help of a suitable reagent such as resin. Resin dispenses at bonding chuck between discs through a needle. Thereafter, capillary action takes place and resin is spread all over the disc. Then the disc goes for spinning. After spinning, disc is picked from spin cup and placed at the UV Area.

Spreading of resin over the discs, prior to spinning is of vital importance, in bonding process. This is achieved in techniques known in the art, by capillary action of capillary tube, so that the glue can reach moat area by capillary action before spinning takes place. However, whenever there is stoppage in line or capillary time fluctuates, there is huge rejection, particularly due to bubble formation, which may go up to 3.5% to 4%.

Furthermore, typically, after spinning, disc is picked from spin cup and placed at the UV Area. Due to improper clearance between pin and disc during this process, 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. Misalignment of handler/gripper fingers is also a common feature. All these result in spin cup gripper life deterioration, causing increase in the cost of production as well.

Hence, it has been observed over the years, that rejection owing to bubble formation and other bonding problems have cropped up undesirable disadvantages, such as increase in the cost of production and technical deficiencies hampering the running performance of the discs.

Attempts are on over the years, to overcome the aforesaid problems so as to ensure an optimum solution for avoiding rejection owing to bubble formation and other bonding problems, whereby increased life of stamper, holder and mold are achieved, with consequential reduction in the cost of production. For example, changing of stamper, stamper holder and mold were undertaken and optimizations of bonding parameters were also attempted. However, the improvements thus achieved, failed to attain the desired level.

Hence, there was a long felt need for providing an optimum solution for avoiding rejection owing to bubble formation and other bonding problems, whereby increased life of stamper, holder and mold is achieved, with consequential reduction in the cost of production. The present invention meets the aforesaid long felt need.

All through out the specification, the words "optical media", "optical discs", "discs", and "DVDRS" are to be interpreted in the broadest sense of the respective terms and any restriction/limitation, if any, referred to in the specification, is solely by way of example and understanding the present invention and not by way of any sort of limitation/restriction.

OBJECTS OF THE INVENTION

It is a principal object of the present invention to provide an improved manufacturing system for optical media, which nullifies/ substantially minimizes rejection due to bubble formation during bonding process.

It is a further object of the present invention to provide a method for manufacturing optical media, including an improved bonding process which nullifies/ substantially minimizes rejection due to bubble formation.

It is a further object of the present invention to provide a method for manufacturing optical media whereby increased life of stamper, holder and mold are achieved, with consequential reduction in the cost of production.

It is a further object of the present invention, to provide an improved method for bonding, involved in the process of manufacturing optical media, which utilizes at least a dummy disc devoid of moat area whereby rejection of discs due to bubble formation and other bonding related problems which occur in the moat area, are nullified)' substantially minimized and also reasonable reduction in consumption of polycarbonate material is ensured.

It is yet another object of the present invention to provide an improved method for manufacturing optical media which reduces the overall cost of production and consequently, the overall cost of the final product.

It is a further object of the present invention to provide a method for reducing resin bubble formation and consequently rejection during the bonding process, involved in
manufacturing optical media.

It is a further object of the present invention to provide at least an improved dummy disc, devoid of moat area and having appropriate inner diameter, preferably of 22 to 23 mm, for its application in the bonding process, involved in the manufacturing method of optical media.

It is a further object of the present invention to provide an improved optical medium, obtained by the improved manufacturing system as stated aforesaid.

It is yet another object of the present inventions to provide a system for manufacturing optical media which is adapted to be reasonably modified in respect of the mold with cut punch and is also adapted for being subjected to minor modifications in lines like suction.

How the foregoing objects are achieved 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

Accordingly, the present invention provides an improved manufacturing system for optical media including means for dye coating, sputtering and bonding wherein said means for bonding is adapted to apply at least a dummy disc devoid of a moat area and having a suitably effective optimum inner diameter, whereby rejection due to bubble formation and other bonding related problems in the moat area, are nullified/ substantially minimized.

In accordance with preferred embodiments of the manufacturing system of the present invention:

-said inner diameter is in the vicinity of 22 to 23rnm.

-all said dummy discs are devoid of moat area.

-said system is adapted to be reasonably modified in respect of the mold with cut punch and is also adapted for undertaking minor modifications in lines like suction.

The present invention also provides a dummy disc for its application in manufacturing of optical media, wherein said dummy disc is devoid of a moat area and has a suitably effective optimum inner diameter such as herein described.

The present invention also provides an improved method for manufacturing optical media including the steps of dye coating, sputtering and bonding, said process for bonding involving joining of active and dummy discs, with the help of suitable agent, dispensing said suitable agent at bonding chuck between said discs, initiation of sucking action for spreading of said suitable agent all over the discs, wherein said method applies at least a dummy disc devoid of moat area and having a suitably effective optimum inner diameter, whereby rejection due to bubble formation and other bonding related problems in the said moat area are nullified/ substantially minimized.

In accordance with preferred embodiments of the method of the present invention: -said suitable agent is resin.

-said inner diameters of said dummy disc is in the vicinity of 22 to 23mm.

-all said dummy discs are devoid of moat area.

-said method is operated by application of a system that is adapted to be reasonably modified in respect of the mold with cut punch and is also adapted for undertaking minor modifications in lines like suction.

The present invention also provides an optical medium, such as a DVDR, manufactured by the method as described hereinbefore.

BRIEF DESCRIPTION OF THE DRAWINGS ACCOMPANYING THE PROVISIONAL SPECIFICATION

The nature and scope of the present invention will be better understood from the drawings accompanying the provisional specification, which are by way of illustration of some preferred embodiments and not by way of any sort of limitation. In the drawings:

Fig 1 illustrates an exploded view of a conventional dummy disc applied in the traditional manufacturing methods of optical media.

Fig 2 illustrates an exploded view of the dummy disc applied in the system and method for manufacturing optical media in accordance with the present invention,

DETAILED 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 traditionally, manufacturing process for optical media such as DVDRS, involves the three principal steps of dye coating, sputtering and bonding. In such manufacturing processes known in the art, bonding involves, joining of active and dummy discs, with the help of resin. Resin dispenses at bonding chuck between discs.
Thereafter, resin is spread all over the disc by application of suitable suction means. Then the disc goes for spinning. After spinning, disc is picked from spin cup and placed at the UV Area. However, this technology has witnessed cropping up of defects, such as rejection due to resin bubble formation and other bonding related problems, particularly in the moat area , resulting in undesirable disadvantages, such as increase in the cost of production and technical deficiencies, hampering the running performance of the discs.
Additionally, such technology was not able to reasonably reduce the consumption of polycarbonate material, in the manufacturing method of optical media.

To sort out the problems, the present invention advocates a system for manufacturing optical media, which is adapted to apply at least a dummy disc devoid of moat area, during the process of joining of active and dummy discs. The system comprises suitable means for dye coating, sputtering and bonding for such applications, all such means being traditional as will be known to persons skilled in the art. However, the uniquely innovative, hitherto unknown aspect of the system lies in the adaptations, implemented on it by trial and experiment for enabling it to apply at least one dummy disc devoid of moat area, having a suitably optimum inner diameter during the process of joining active and dummy discs, involved in the manufacturing process of optical media.

The system and method for manufacturing optical media in accordance with the present invention applies at least a dummy disc without a moat area, having a suitable optimum inner diameter. Such diameter is preferably in the vicinity of 22 to 23 mm.

The dummy disc without mote area in accordance with the present invention has been illustrated in figure 2, which is self-explanatory when compared with figure 1 which illustrates a conventional dummy disc having a moat area.

The system in accordance with the present invention is also adapted to apply dummy discs which are alt devoid of moat area, during the process of joining active and dummy discs.

The improved method for manufacturing optical media according to the present invention includes the steps of dye coating, sputtering and bonding as usual. The uniquely innovative, hitherto unknown aspect lies in the process of bonding involving joining of active and dummy discs, with the help of suitable agent, dispensing said suitable agent at bonding chuck between said discs and initiation of sucking action for spreading of said suitable agent all over the discs, wherein at least a dummy disc devoid of moat area and having a suitably effective optimum inner diameter is applied, whereby rejection due to bubble formation and other bonding related problems in the said moat area are nullified/ substantially minimized. This method applies a system for manufacturing optical media, which is adapted to be reasonably modified in respect of the mold with cut punch and is also adapted for being subjected to minor modifications in lines like suction. The suitable reagent applied may be resin.

The optical media generated by applying the system and method according to the present invention, may be DVDRS and the like. Such optical medium, such as a DVDR are obtained by the usual process of dye coating, sputtering and bonding, but during the process of joining active and dummy discs in the bonding step, one or more dummy discs which are devoid of moat area having a suitable inner diameter are applied. The system is adapted to be reasonably modified in respect of the mold with cut punch and is also adapted for being subjected to minor modifications in lines like suction.

By application of at least one dummy disc without mote area and having appropriate inner diameter, the following advantages are achieved in a nutshell:

1. Rejection due to resin bubble formation is nullified/ substantially minimized.

2. Bonding related problems, particularly cropping up in the moating area are minimized.

3. Increased life of stamper, stamper holder and mold are achieved.

4. Cost of production and consequential cost of final product are reasonably reduced.

5. Reasonable reduction in consumption of polycarbonate material is achieved.

6. Other technical deficiencies hampering the running of the discs are minimized.

The technical advancements and economic significance as discussed hereinabove were hitherto unknown and not conceived by persons skilled in the art.

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 claimed in the appended claims.

WE CLAIM:

1. An improved manufacturing system for optical media including means for dye coating, sputtering and bonding wherein said means for bonding is adapted to apply at least a dummy disc devoid of a moat area and having a suitably effective optimum inner diameter, whereby rejection due to bubble formation and other bonding related problems in the moat area, are nullified/ substantially minimized.

2. The improved manufacturing system as claimed in claim 1 wherein said inner diameter is in the vicinity of 22 to 23mm.

3. The improved manufacturing system as claimed in any preceding claim, wherein all said dummy discs are devoid of moat area.

4.The improved manufacturing system as claimed in any preceding claim, wherein said system is adapted to be reasonably modified in respect of the mold with cut punch and is also adapted for undertaking minor modifications in lines like suction.

5. A dummy disc for its application in manufacturing of optical media, wherein said dummy disc is devoid of a moat area and has a suitably effective optimum inner diameter such as herein described.

6.An improved method for manufacturing optical media including the steps of dye coating, sputtering and bonding, said process for bonding involving joining of active and dummy discs, with the help of suitable agent, dispensing said suitable agent at bonding chuck between said discs, initiation of sucking action for spreading of said suitable agent all over the discs, wherein said method applies at least a dummy disc devoid of moat area and having a suitably effective optimum inner diameter, whereby rejection due to bubble formation and other bonding related problems in the said moat area are nullified/ substantially minimized.

7. The improved method as claimed in claim 6, wherein said suitable agent is resin.

8. The improved method as claimed in any of claims 6 or 7, wherein said inner diameter of said dummy disc is in the vicinity of 22 to 23mm.

9. The improved method as claimed in any of claims 6, 7 or 8, wherein all said dummy discs are devoid of moat area.

10.The improved method as claimed in claims 6 to 9, wherein said method is operated by application of a system that is adapted to be reasonably modified in respect of the mold with cut punch and is also adapted for undertaking minor modifications in lines like suction.

11. An optical medium, such as a DVDR, manufactured by the method as claimed in claims 6 to 10.