DISCS FIELD OF THE INVENTION

The present invention relates generally to the field of optical storage media. More particularly, the present invention relates to a method and apparatus for use in the custom shaping of optical storage discs. BACKGROUND OF THE INVENTION

The use of optical storage media including CD's (Compact Discs) and DVDs (Digital Versatile Disc or Digital Video Disc) is well known. Read-only and read-write CDs and DVDs are presently one of the preferred means for storage of large amounts of digital information and have considerable market acceptance. Both CDs and DVDs have different forms based on the properties of the discs, including both read-only and read- write forms. With respect to read-only CDs, these discs are referred to as CD-ROMs, read- write CDs may be referred to as CD-Rs (Compact Disc - Writeable) which include both WORM (Write Once Read Many) discs and CD-RWs (Compact Disc Re- Writeable or Write Many Read Many). With respect to DVDs, DVDs are often referred to as DVD-R and DVD-RW designating read and read-write versions respectively.

As is known, the design of a read-only CD or DVD includes a circular piece of injection-molded and transparent plastic (usually polycarbonate) around 1.2 millimetres thick and having a 12 centimeter diameter. With read-only discs, the polycarbonate includes a long, tight spiral originating at the centre of the disc and having billions of tiny bumps. The bumps, when coated with an aluminum reflective layer can be read by a combined laser and opto-electric device and are interpreted as data bits. In addition to the aluminum reflective layer, the CD includes an acrylic coating of the aluminum layer and may include a label adhered to the acrylic layer. The laser is directed through the polycarbonate layer.

The recordable CD and DVD differs from the read-only media in the reflective layer and the absence of physical bumps in the polycarbonate plastic. Rather, the recordable CD or DVD includes a data layer comprising a chemical compound which may be altered to represent the light equivalent to a physical bump. WORM media utilize an

organic dye which is normally reflective but when heated to a particular temperature by a laser causes a colour change, thereby optically representing a bump.

CD-RWs also use a specialized reflective layer as in the WORM media. More specifically, multiple RW technology uses a specialized compound which is an alloy of antimony, indium, silver and tellurium. This compound will undergo different phase changes when heated to different temperatures. If the compound is heated to a first lower temperature, the compound will crystallize as it cools and become reflective. If the compound is heated to a higher temperature, the compound will not crystallize as it cools and have a dull appearance. Accordingly, depending on the temperature that the media is heated to will determine whether the compound will represent a bump. Furthermore, because the chemistry does not change as result of the heating temperature, the media may be erased and re-recorded.

CD/DVD media can store upwards of 780 Mbytes of data on the conventional 12 cm disc. With such a large amount of storage capacity, it is often not required that the full available surface area be available for data storage, thereby permitting the creation of CD/DVD media having a smaller but different shape to the conventional circle. For example, discs can, theoretically, be shaped to almost any shape where a reasonable amount of data storage area remains on the disc.

Although certain shapes can be made through moulding processes, past techniques for shaping discs to shapes other than the standard 12 cm circle format have primarily used computer controlled shaping devices which utilize a high speed rotating cutting spindle to create a desired shaped from a circular blank. While this technique is effective in efficiently shaping large quantities of discs, the process often damages the data storage media immediately adjacent the edge thereby affecting the visual appearance of the shaped disc as well as reducing the amount of data storage media which may lead to read and write errors with respect to any data stored thereon. This problem is particularly noted in the shaping of read-write compact discs and DVDs, where the data storage media is more fragile than that of a read-only CD.

With respect to recordable CD/DVD technologies, in view of the absence of physical bumps, the relative strength of adhesion of the data layer to the plastic substrate is reduced and, as a result, makes shaping of the CD by conventional shaping techniques

difficult. That is, traditional methods of shaping CDs results in substantial damage to the data layer inside the immediate edge.

Accordingly, there has been a need for a system which provides an effective and efficient method of shaping optical storage discs to any desired shaped and which provides an undamaged edge on the optical discs.

More specifically, there has been a need for a method of shaping discs wherein the disc is shaped by a stamping and/or shearing process which provides a shearing pressure to the disc which results in an undamaged edge and which seals the cut edge. Still further, there has been a need for a method that enables rapid creation of shaped discs at a reasonable price.

Direction to produce shaped OSDs can be found, for example, in US 6,510, 124, which describes a storage disc similar in shape and size to a business card or credit card. US Patent 5,942,165 describes the application of artwork to a CD and the shaping of CDs to match the outline of the artwork. Notably, limited direction is given as to how the shaping may be accomplished, however suggestions are provided such as laser-cutting or moulding. US 6,612,789 describes a CD shaping apparatus and method in which cutting is accomplished by a router-type tool. Similarly, US 5,882,555 describes a method of shaping CDs by grinding away undesired portions of the disc.

Although methods for stamping/die-cutting a desired shape into an optical storage disc have been briefly suggested in the prior art (see for example US 5,882,555), known die-cutting methods are not suited for use in die-cutting through a data layer of an OSD, and attempts to do so have generally resulted in damage to the data layer of the shaped disc such that a significant portion of the remaining data layer is unusable. Notably, previous stamping methods have simply been applied from other art fields, without appropriate adaptation or consideration to the fragility of optical storage discs.

A successful method for die-cutting optical storage discs is provided in US 10/021,475. The method disclosed therein may be used for cutting through a data layer of the OSD, and results in a shaped OSD in which damage to the remaining data layer is minimized.

Although US 10/021 ,475 teaches a successful method for die-cutting an OSD, it does not address problems encountered during mass manufacturing of shaped OSDs such as speed and efficiency.

It is, therefore, desirable to provide an apparatus for die-cutting shaped OSDs from standard OSDs on a large scale while preserving the integrity of the data layer within the cut product. SUMMARY OF THE INVENTION

It is an object of the present invention to obviate or mitigate at least one disadvantage of previous methods and systems for shaping OSDs. In a first aspect, the present invention provides a die set for use in shaping optical storage discs to a desired shape comprising: a die plate defining an aperture corresponding to the desired shape, the die plate including a cutting edge surrounding the aperture on a first surface of the die plate; a punch corresponding to the desired shape; and an advancing system for advancing the die set through the aperture to cut an OSD, thereby producing a shaped OSD.

In one embodiment, the die set further comprises a biasing system for applying counterpressure to the data layer of the OSD adjacent the cutting edge and against the punch as the die set is advanced. The biasing system may be a pressure plate, which may also correspond to the desired shape and may have a concave centre. When a pressure plate is included, in one embodiment, the pressure plate is operable between a retracted position proximal a second surface of the die plate opposite the first surface; and an extended position wherein the pressure plate extends through the aperture of the die plate to bias the data layer of OSD adjacent the cutting edge against the punch. In a second aspect of the invention, there is provided a system for applying sealant to the edge of an optical storage disc comprising: a support for supporting an OSD to be sealed; a sealant applicator having a body for containing sealant, a nozzle operatively attached to the body for dispensing sealant from the body onto the edge of the OSD, and a dispensing system for dispensing sealant from the body through the nozzle. In one embodiment, the dispensing system includes a piston disposed within the body of the applicator and a drive system for driving the piston towards the nozzle to

dispense sealant from the nozzle. The nozzle may have a tapered tip that is open at the end and sides to permit dispensed sealant to drag along the edge of the rotating OSD.

In a further embodiment, the support is a rotatable pedestal for rotatably supporting the OSD. In a further embodiment, the system includes programmable drive means for rotating the pedestal and OSD while sealant is dispensed from the nozzle.

In a further embodiment, the sealant applicator is mounted upon a track and is moveable towards or away from the pedestal by a linear actuation system.

In a third aspect of the invention, there is provided an automated system for cutting optical storage discs (OSDs) to a shaped OSD having a desired shape comprising: a loading station for receiving and transporting OSDs and shaped OSDs; an orientation station operably connected to the loading station for orienting individual OSDs; a feeding station operably connected to the orientation station for feeding oriented OSDS to a die-cutting station, the die cutting station for die-cutting an

OSD to a shaped OSD; a sealing station operably connected to the die-cutting station for applying a sealant to a cut edge of a shaped OSD; a curing station operably connected to the sealing station for curing a sealant- sealed shaped OSD and wherein the curing station is operably connected to the loading station.

In a fourth aspect of the invention, there is provided a method for producing a shaped OSD of a pre-determined shape from a standard round OSD, comprising the steps of: compressing the inner data layer of an OSD between a punch corresponding to the pre- determined shape and a pressure plate having a corresponding shape; and advancing the OSD through a die plate having a cutting edge corresponding to the desired shape to cut the OSD, thereby producing a shaped OSD.

In one embodiment, the pressure plate corresponds to the desired shape, and the pressure plate and punch compress the OSD at the edges of the desired shape as the OSD is cut.

In another embodiment, the method includes the step of applying sealant to the edges of the shaped OSD.

In a further aspect of the invention, a method is provided for applying sealant to the circumference of an OSD comprising the steps of: placing an OSD on a support; positioning a sealant applicator proximal to an edge of the OSD; and rotating the support or the applicator while dispensing sealant from the applicator, thereby applying sealant to the circumference of the OSD.

In one embodiment, the support is a rotating pedestal.

In an embodiment, the method further comprises the steps of: determining the shape of the OSD, and continually adjusting the position of the sealant applicator during rotation of the OSD to maintain a constant distance between the nozzle and the nearest edge of the OSD.

In another embodiment, the method further comprises the step of controlling the speed of pedestal rotation such that the nozzle maintains a consistent travel speed with respect to the linear distance of the OSD edge.

Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:

Fig. 1 is a cross-sectional schematic view of a die set in accordance with an embodiment of the invention;

Fig. 2 is a plan view of a stripper plate and nested punch in accordance with an embodiment of the invention;

Fig. 3 is a schematic side view of a sealant station in accordance with an embodiment of the invention;

Fig. 4A and 4B are top and side schematic views, respectively, of a sealant applicator nozzle in accordance with an embodiment of the invention; Fig. 5 is a schematic plan view of a system for shaping OSDs in accordance with an embodiment of the invention; and

Fig. 6 is a schematic plan view of the system shown in Figure 5, including an load/unload station.

DETAILED DESCREPTION

Generally, the present invention provides a method and apparatus for die-cutting optical storage discs. Specifically, a method and apparatus are provided for shaping a standard optical storage disc (OSD) by die-cutting. When the OSD is cut, the data layer of the OSD is also cut, but damage to the data layer at the edge of the shaped OSD is minimized. The resulting shaped OSD will therefore have a usable data layer that extends from the innermost point of the data layer to approximately the innermost outer edge of the shaped OSD. In effect, the radius of the data layer is maximized within the available space provided by the shaped OSD. Die Set

A die set 1 1 in accordance with the invention is shown in Figure 1. The die set 1 1 minimally includes a punch 12 and a die platel3. The punch 13 reflects the desired size and shape of the shaped OSD product. The die plate 13 includes a raised cutting edge 14 corresponding to the desired shape. In the embodiment shown in Figure 1, an aperture 15 is defined within the area enclosed by the cutting edge 14, and the aperture 15 is encircled by a perpendicular wall portion 15a adjacent the cutting edge 14, and a continuous tapered wall portion 15b extending to the opposing side of the die plate 13. Thus, the die set 11 may include a first surface 13a having a cutting edge 14 surrounding an aperture 15, the aperture 15 at the first surface 13a corresponding to a desired shape and size of the final shaped OSD; and a second surface 13b having a larger aperture which may or may not also correspond to the desired shape.

In the embodiment shown in Figure 1, the punch 12 is nested within a stripper plate 16. Prior to loading of an OSD into the die, the top surface of the punch 12 is preferably level with the top surface of the stripper plate 16 to provide an even surface for loading the OSD. As shown in Figure 2, the stripper plate 16 supports the outer regions of the OSD. The nested punch 12, in the embodiment shown, also includes an alignment hole 17 to assist with alignment of the OSD, and may receive a pin 18 from a pressure plate 19, if present, as will be explained below.

After loading an OSD, the punch 12 is raised from the stripper plate 16 to force the OSD against the cutting edge 14 and produce the shaped OSD. Once the OSD is cut, the punch 12 will continue to extend through the aperture 15 of the die plate 13 to push the

shaped OSD through the perpendicular wall portion 15a of the aperture to the tapered portion 15b or through the tapered portion 15b for retrieval. The tapered portion 15b of the die aperture 15 minimizes the shear force against the newly cut and unsealed edges of the shaped OSD. One of skill in the art will recognize that the stripper plate 16 is not a critical feature, as the OSD may be loaded onto the punch surface. Moreover, it is also possible to alter the mechanics of the die set 1 1 such that the die plate 13 or the punch 12, or both, advance to force the OSD against the cutting edge 14.

As shown in Figure 1, the die set 11 will preferably include a pressure plate 19. The pressure plate 19 is particularly useful in cutting DVDs and recordable OSDs where the risk of damage to the data layer is greater due to the physical structure of the data layer. In order to achieve a shaped OSD having a clean edge with minimal damage to the data layer of the shaped OSD, the OSD should be cut with the inner data layer (that is, the portion of the data layer that will subsequently contain a useable data area) under compression. The pressure plate 19 is advanced to contact the OSD when supported by the punch 12, and applies an opposing force to the punch 12 as the die set 1 1 is advanced. The pressure plate 19 may include a substantially flat surface for contacting the OSD, or the pressure plate 19 may be concave in the center such that the pressure plate 19 applies compressive force mainly adjacent the anticipated edges of the shaped OSD. Further still, in one embodiment, the pressure plate 19 will include a OSD gripping system such as a vacuum system 19a to retain the shaped OSD against the pressure plate as the punch 12 is withdrawn (as explained below).

As noted above, the pressure plate 19 is advanced towards the punch 12 and biases the OSD against the punch 12 prior to contact of the OSD with the cutting edge 14. As the die set 1 1 is advanced, the motor driving the pressure plate 19 continues to force the pressure plate 19 against the OSD, however, this force is overcome by the motor advancing the die set 1 1 to force the OSD through the die plate 13 . Once the shaped OSD has cleared the perpendicular walls 15a of the aperture 15, and preferably has cleared the die plate 13 completely, the compressive force is released.

The pressure plate 19 may also include a pin 18 for maintaining alignment of the OSD during compression and cutting. The pin 18, if present, passes through the centre hole of the OSD and into the hole 17 within the punch.

Experimental results have shown that to produce an optimal edge, the OSD should be advanced through the die plate 13 with a net force of at least 400 pounds per linear inch of shaped edge. For example, if the shaped OSD is a circle, the circumference of the circle would be measured in inches and multiplied by 400 to determine the net amount of force required. Alternatively, a sawtooth design, for example, would have a larger linear edge than a circle of the same diameter and thus would require more force in order to achieve a clean cut edge. The required force is calculated for each desired shape prior to cutting.

Of course, the total force required to advance the die will not simply be equal to this calculation, as other considerations must be made in determining the total force required to advance the die. For example, the counterpressure applied by the pressure plate 19 must be added to the net force, as well as any other inherent forces or friction present within the system in order to determine the total cutting force required by the punch 12. Sealant Application

Sealant is applied to the edge of the shaped OSD to protect the exposed data layer and/or to provide an aesthetically acceptable finish to the OSD edge. In one embodiment, an OSD may be placed on a support 31 proximal to a sealant applicator 32. As shown in Figure 3, the sealant applicator 32 includes a housing having a sealant chamber 33 for containing sealant, a nozzle 34 for dispensing sealant from the chamber 33, and a piston 35 for advancement towards the nozzle 34 to force sealant therethrough. The sealant applicator 32 may be mounted on a track 36, and is driven towards or away from the OSD by a servo-motor, depending on the shape of the OSD, to maintain a constant distance between the nozzle 34 of the applicator and the nearest edge of the OSD. When the radius of the OSD at the edge of the OSD closest to the nozzle 34 is larger, the sealant applicator 32 would be driven away from the OSD pedestal 31 by an appropriate distance. Conversely, when the radius at the closest edge is lesser, the sealant applicator 32 would be driven towards the pedestal 31 by an appropriate distance. It is preferable that the bead of sealant be evenly applied to the entire edge of the

OSD to re-bond the data layer of the OSD to the plastic edge of the OSD, and the support

31 , in one embodiment, is a rotating pedestal for rotating the OSD with respect to the sealant applicator. As various shapes of OSD will have various linear edge measurements (as explained above), the rotation of the pedestal 31 is coordinated with the movement of the sealant applicator 32 to ensure that the linear travel of the edge of the OSD past the nozzle 34 is relatively constant. Thus, the speed of rotation at any point would be controlled according to the shape of the OSD to ensure that the linear travel of the nozzle is consistent around the entire edge of the OSD. Appropriate algorithms, controllers, processors, and motors may therefore be required to analyze the shape of the OSD and control both the rotation of the pedestal and the linear movement of the sealant applicator as required.

The nozzle 34 of the sealant applicator 32 is preferably tapered at the dispensing end 37 when viewed from the top, as shown in Figure 4A, and the opening is preferably recessed at the dispensing end when viewed from the side, as shown in Figure 4B. The recessed opening is preferred to permit a bead of sealant to be dispensed from the end or sides of the nozzle tip. For example, as the shaped OSD rotates with respect to the nozzle, the dispensed sealant may be positioned along the edge of the shaped OSD to follow the contour of the OSD edge. If the nozzle tip was not recessed, the applicator 32 may require multi-axis movement and control of the applicator to apply sealant to certain shapes of OSD. The recessed tip avoids this, thus providing more reliable control of the sealant application without complicating the control algorithm and mechanics.

It should be understood that instead of a rotating pedestal, the sealant applicator may be rotated around the edge of the OSD. Alternatively, the entire process could be carried out manually.

After sealant is applied, the sealant must be cured prior to handling, for example, by time or if required by the specific sealant formulation, under UV light. Automated System

The die set and sealant applicator and curing system described above is preferably operable within a larger automated system for producing shaped OSDs. In the embodiments of the invention shown in Figures 5 and 6, a system is provided for shaping optical storage discs. The apparatus includes load/unload station 50, an orienting and feeding station 20, a die-cutting station 10 , a sealant application system and a curing

station. Spindles of uncut OSDs are loaded at position A where they are linearly advanced towards the orienting and feeding station 20 in a stepwise manner. Upon reaching the orienting and feeding station 20 (position B), individual OSDs are oriented to ensure correct alignment of the label of OSD with respect to the punch and die, preferably through optical alignment and mechanical rotation of an individual OSD. An aligned OSD is individually moved to position C for loading to the die cutting station 10 at position D. At the cutting station 10, a die set punches the desired shape into the OSD and advances the resulting shaped OSD to the sealant application station 30 (postion E). The remaining portion of the OSD is removed from the cutting station for disposal. Once sealant has been applied to the edges of the shaped OSD, the shaped OSD is advanced to the curing station 40 (position F) where the sealant is cured . Thereafter, individual shaped OSDs are loaded back onto spindles at position G for stepwise advancement for unloading at position H. Orienting and Feeding Station

The orienting and feeding station 20 supports labelled OSDs that are to be cut. If the OSDs are pre-labelled and the desired OSD shape is asymmetrical, the OSDs should be properly oriented prior to loading into the cutting station 10. For example, each OSD may include an alignment mark that is read by an optical sensor to direct the orientation of the OSD as it is loaded into the cutting station 10. Cutting Station The OSD is fed into the cutting station 10 by the feeding device 21 in proper orientation, and is received on the stripper plate 16. The punch 12 then raises the OSD from the stripper plate 16, and the pressure plate 19 is lowered to compress the OSD and inner data layer against the punch 12. In the embodiment shown, the portion of the OSD that will form the shaped OSD is under compression, while the waste portion is not compressed. The punch 12 is then advanced with a total force sufficient to overcome the downward pressure of the pressure plate 19 and with a net force in the order of 400 pounds per linear inch of shaped OSD edge, which has been predetermined. As the punch 12 is raised, the OSD will be cut to the desired shape by contacting the cutting edge 14 of the die plate. The punch 12 continues to rise until the shaped OSD clears the perpendicular walls 15a of the die plate aperture 15. The punch 12 is then reversed to return to its original nested position within the stripper plate 16. In an embodiment, the pressure plate

19 includes a vacuum 19a or other retention system to retain the shaped OSD against the pressure plate 19 when the punch 12 is reversed.

While the shaped OSD is retained against the pressure plate 19, the pressure plate 19 is moved laterally to position the shaped OSD above the support pedestal 31 of the sealant station. The shaped OSD may then be lowered and released onto the support pedestal 31 in proper alignment for sealant application.

As the pressure plate 19 returns, the waste portion of the shaped OSD that remains on the stripper plate 16 may be discarded and a new OSD is loaded onto the stripper plate 16 and punch. In one embodiment, the loading of a new blank OSD by the orientation and feeding station 20 pushes or sweeps the outer cut region of the OSD to a disposal area 22. Sealant Station

When a shaped OSD is placed upon the support pedestal 31, the sealant process is initiated to dispense sealant from the nozzle 34 of the applicator, rotate the support pedestal 31, and adjust the linear position of the applicator 32. As discussed above, the sealant applicator 32 may be advanced towards or away from the shaped OSD on the pedestal 31 to ensure a constant distance between the nozzle 34 and the edge of the shaped OSD. The rotation of the support pedestal 31 is also controlled ^' to ensure a consistent travel speed of the nozzle 34 with respect to the edge of the shaped OSD. Curing station

As a cut OSD is transferred to the sealant station support pedestal 31, the sealant station may similarly include an arm (not shown) with a vacuum or other retention system to simultaneously transfer a sealed OSD to a curing support 41 within the curing station 40. In one embodiment, the sealed shaped OSD is retained within a UV oven 42 for a time sufficient to cure the sealant bead. As the required curing time may be longer than the time required for cutting and sealing of the OSD, the curing station 40 may include several curing supports 41 within the UV oven 42. Such supports may be linearly or rotatably advanced with respect to one another as known by those skilled in the art.

The above-described embodiments of the present invention are intended to be examples only. Alterations, modifications and variations may be effected to the particular

embodiments by those of skill in the art without departing from the scope of the invention, which is defined solely by the claims appended hereto.