Patent Application
20060187805
The present invention relates to the production of an optical disc with a detachable module. The invention also relates to an embodiment of such an optical disc with a detachable module.
Optical discs (CD, MiniDisc, CD-ROM, Digital Video Disc) are typically produced by injection moulding with a so-called stamper in a mould form. Such a process is described in European patent 296 677 by Cools and assigned to Philips. For the production of the stamper, a glass plate is covered with a resin that is laser illuminated and developed. Subsequently, the resin is covered with a metallic layer, typically Nickel, by sputtering and galvanic processes. The Nickel stamper is then removed from the glass and can after removal of the resin be used as a mould form in mould processes for optical disc production.
Typically, the stamper is adapted to the diameter of the mould form which normally is slightly larger in diameter than the final optical disc. In the mould form, the stamper is centered and fixed to ensure high accuracy during the moulding procedure. The mould is then closed and polymer, typically polycarbonate or PMMA (polymethylmethacrylate), is injected into the form at a temperature substantially over the melting temperature of the polymer, typically 340° C. for polycarbonate. The temperature has to be on the one hand lower than the temperature where the polymer start disintegrating and on the other hand so high that the polymer flows quickly in the mould form in order to avoid too large strain in the optical disc when it is removed from the mould.
Electronic modules like SIM plugs may be integrated in such optical discs. Such combinations are known from German patent application DE 199 05 588 by Bierlich assigned to Deutsche Telekom AG. In order to be able to remove the electronic module easily from the remaining carrier card with optical disc, a number of solutions have been proposed, for example in German Utility Model DE 201 02 719U by C.U.B.A. and in German patent application DE 199 43 092 by Lüke assigned to Orga. Neither of these two documents disclose a possible method for production of the disclosed optical disc with electronic module.
The term optical disc has to be understood in a general sense as a digital data carrier with optically readable data tracks, even though the shape of the digital data carrier may have shapes that differ from a circular form.
In German Utility Model DE 201 02 719U by C.U.B.A., a SIM plug can be removed from the optical disc by breaking two connecting bridges. However after breaking, the remaining SIM plug will have remains from the bridges such that the edge with the broken bridges is not smooth. The tolerances for the size of SIM plugs to be used in telephones are narrow such that the SIM plug as described in this document is not suited for ordinary usage.
In German patent application DE 199 43 092 by Lüke, a separation line can be broken to separate an electronic module from an optical disc. This optical disc with the module is produced by injection moulding, where the thickness of the electronic module is different from the thickness of the optical disc. However no clear advice is given for how to produce such an optical disc. In fact, a number of precautions have to be taken for such a process as will be apparent in the following, which is a reason why, so far, no such products are commercially available.
A general aim for a product where an electronic module like a SIM plug is connected to an optical disc, which then functions as a carrier, is to observe the ISO 7810 standard. The ISO 7810 standard governs the position for the placement of the SIM plug on such a carrier, where the carrier according to this standard has a length of 85.6 mm and a width of 53.9 mm—which is the standard size of a credit card. Electronic modules on cards of ISO 7810 standard, for example as described In European Patent EP 495 216 by Blome and Freise assigned to Orga, are well known to produce because such cards are used in telephones, especially elder telephones, in parallel to SIM plugs. Normally, the cards are prefabricated, after which a SIM electronic circuit is placed on the card in other existing machines. The configuration of the electronic circuit is governed by another standard, namely the ISO 7816. Such other existing machines producing electronic circuits on such prefabricated ISO 7810 carriers are not suited for the production of most known optical discs with SIM plugs, because the fixed placement according to ISO 7810 of the SIM plug on the carrier card and the size of the SIM plug itself leaves not enough space for the optical disc tracks to contain data. This is a problem faced by the shown embodiments in German patent application DE 199 43 092 by Lüke and assigned to Orga. A way to overcome this difficulty is a complete new construction of production machines for placement of the electronic module. The difficulty with the placement of the SIM module on an ISO 7810 standard card with an optical disc Is one of the problems to be solved.
In the aforementioned German patent application DE 199 43 092 by Lüke, there is no stated restriction on the actual size and shape of the optical disc with the SIM plug. However, the disclosure should be seen in the light of existing standards, for example the ISO 7810 standard that is mentioned in this German patent application. Also, though not restricted to the shape of the card in this document, only quadratic optical disc's are shown to which a SIM plug is attached. It is also mentioned in this document, that the quadratic form is preferred with an edge of 54 mm. This combination of features leads to another problem, namely that the diagonal length of the carrier card with the optical disk is 76 mm, which is 4 mm shorter than the minimum length required for a CD to be played in a large number of optical CD drive unit. For example, a CD of less than 80 mm will only be read properly in 60-70% of existing CD drive units. Thus, also in this respect, German patent application DE 199 43 092 gives no clear advice for how to construct a satisfactory CD with SIM plug. This is another problem to be solved.
It is the purpose of the invention to provide a method for production of an optical disc with a detachable module, for example an electronic module and preferably a SIM plug, where the module after detachment has a smooth edge. Especially, it is the further purpose of the Invention to provide a product that functions properly.
This purpose is achieved with a method according to the invention as described in the following.
A method is herewith disclosed for production of an optical disc with a detachable module, the method comprising the provision of a mould with mould cavity having internal dimensions corresponding to the dimensions of an optical disc with the detachable module, said mould having supplier means for supplying molten polymer into the mould. A stamper is provided in the mould cavity, said stamper having a surface towards the interior of the mould cavity, said surface having a surface structure being the counterpart for the corresponding surface structure of the moulded optical disc. Molten polymer is supplied into the mould cavity, said molten polymer filling the remaining space inside the mould cavity, after which the polymer is cooled to a temperature where the polymer is hardened. Finally the moulded optical disc is removed.
In order to establish a smooth, preferably linear, groove for a breaking line between the optical disc and the detachable module, a line restrictor is provided restricting the thickness of the optical disc with detachable module along at least one breaking line between the optical disc and the detachable module.
By providing a line restrictor according to the invention, it is not necessary to perform any milling action along this line for establishing a linear groove, which facilitates the production process tremendously as compared to known processes. An optical disc with detachable module is in this way according to the invention produced in one step with a precise shaping during the moulding process.
The method according to the invention may as well comprise the provision of a thickness restrictor for restricting the thickness of the detachable module, for example to 0.85 mm, in an area that is intended to include an electronic circuit.
In as far as the detachable module is or contains a SIM plug, the thickness of the SIM plug will be between 0.8 mm and 0.85 mm in order to fulfill thickness requirements, whereas the thickness of the optical disc is typically 1.2 mm. Optionally, already during the moulding, the detachable module is produced thinner than the optical disc.
As explained in the introduction with reference to European patent EP 296677 and references therein, there exist standard moulds for standard optical discs. In order to use these standard moulds, it has turned out that it is very advantageous to provide an insert which is insertable into such standard moulds, where the insert restricts the internal dimensions of the mould in order to shape the optical disc differently from a standard optical disc.
This insert may be shaped such that the optical disc is not circular but has other shapes, for example quadratic or rectangular. The insert may also comprise a module restrictor for restricting the thickness of the detachable module.
As far as the detachable module comprises a SIM plug, the SIM plug itself may have a thickness of 0.8 mm and comprises in addition a hollow in the SIM plug into which the electronic circuit is replaced. The module restrictor according to the invention may take account for the simultaneous production of this hollow in the SIM plug.
The line restrictor inside the mould reduces the speed at which the polymer may flow across the line restrictor. Because the distance between the edge of the restrictor and the opposite internal side of the mould is only spaced a short distance, the polymer is prevented from flowing across the line restrictor as freely as in the rest of the mould cavity. Therefore, temperature differences may occur across the hardening optical disc with detachable module which again may result in strain inside the hardened optical disc. This may have the consequence that the optical disc with the detachable module bends, when removed from the mould resulting in a non-satisfactory product.
In order to minimize such temperature differences when the polymer is injected into the mould and flowing inside the mould to fill the cavity completely, the invention has foreseen a further development, where the line restrictor is comprised by a movable plunger in order to establish the breaking line. Such a plunger is preferably moved in a direction approximately orthogonal to the optical disc into the mould cavity. This action is performed after having supplied polymer into the cavity and before this polymer hardens. As the line restrictor is not inside the cavity during the filling of polymer into the mould, the polymer can flow freely inside the remaining cavity such that temperature differences across the polymer in the cavity is avoided. Still being a fluid, the plunger in the form of a line restrictor is inserted and forms the groove for the breaking line between the detachable module and the optical disc. Though only one line restrictor and one plunger is mentioned in the foregoing and the following, this has to be understood also such that more than one line restrictor and plunger may be provided and used.
The detachable module that may be used for a SIM plug as mentioned earlier which has to be provided with a hollow for insertion of an electronic circuit. Also such a hollow can be produced by a plunger that is inserted into the cavity. Typically, a SIM plug has one hollow for the electronic circuit and inside this hollow a second, deeper hollow for attaching the electronic circuit to the SIM plate. This means that the material thickness of the polymer of the SIM plug at the thinnest is 0.2 mm. This implies in practice, if the mould form is solid without a plunger, that polymer has to flow between two faces of 0.2 mm distance. In such a narrow region, the polymer may cool faster than in the rest of the cavity, which may induce stress in the optical disc with a detachable module as describe earlier. By using a plunger to form this deep second hollow in the SIM plug such a too-fast-cooling is avoided.
For the amount of polymer to be injected into the mould, the volume of the plungers is taken into account.
By using plungers to provide grooves for breaking lines and, optionally, a hollow in the detachable module, the tolerances for injection speed of the polymer, for the time for the moulding process, for the pressure on the polymer and for the cooling time are much less strict than in corresponding processes without such plungers.
Once the optical disc has been removed from the mould, a reflective layer, typically a nickel layer, is provided on that side of the optical disc which has been facing the stamper. On top of this reflecting layer, a coating is applied. On standard optical discs such coating is spun on the surface after which a print is provided on the surface coating.
For a disc with detachable module according to the invention, such a spinning method is not optimal, because the coating may accumulate in the groove for the breaking line. Therefore, in a further development of the invention, it is foreseen that the surface coating is applied by spraying or by silk screen printing. It has turned out that spray-coating has another advantage as compared to spun coating as will be apparent in the following. A spun coating has typically a layer thickness 50 μm. Because a SIM plug has a very well-defined thickness, a 50 μm spun coating on the surface would imply that the polymer thickness between the glue in the hollow of the electronic module and the spun coating is only 0.15 mm, which is very thin and which easily may lead to deformation of the SIM plug during moulding and also during hardening of the spun coating and the applied glue inside the hollow. By applying spray coating, the coating on the SIM plug can be made thinner or be completely avoided, such that the wall thickness is not 0.15 mm but 0.2 mm, which results in a higher stability against bending of this thin wall.
The spray-coating that is applied to the reflective side of the optical disc may be an ultra violet hardening coating or varnish. It should be non-corrosive for the reflective layer, for example nickel coating or aluminum coating.
The injection moulding device for manufacturing optical discs with a detachable module from a polymer material according to the invention comprises a mould with a first and second mould section which are movable relative to another between an open and closed position. Between the first and second mould section in a closed position, a mould cavity is defined into which a moulding polymer is injectable to form the disc with the detachable module. The injection moulding device comprises a stamper in the mould cavity having a surface towards the interior of the cavity. The surface of the stamper has a surface structure being the counterpart for the corresponding surface structure of the moulded optical disc. The injection moulding device furthermore comprises at least one line restrictor for restricting the thickness of the optical disc with the detachable module along at least one breaking line between the optical disc and the detachable module.
The injection moulding device in a further development of the invention also comprises a module restrictor for restricting the thickness of the detachable module. The module being optionally intended for receiving an electronic circuit.
In an even further embodiment of the invention the mould is a standard mould for standard optical discs and the injection moulding device comprises in addition an insert insertable into the standard mould. The insert inside the standard mould restricts the internal dimensions of the cavity of the mould in order to shape the optical disc with detachable module differently from standard optical discs.
Preferably, the at least one line restrictor is comprised by a plunger moveable into the cavity of the mould, preferably in a direction approximately orthogonal to the optical disc. The at least one line restrictor is intended to be moved into the cavity of the mould, after having supplied moulding polymer into the cavity and before this polymer hardens.
A line restrictor is preferably provided with a tapering form having a taper angle of less than 15 degrees, preferably less than 12 degrees and most preferably less than 10 degrees on the side that is facing the module.
The taper angle facing the module should be rather small if the module is desired with very well defined dimensions and steep side edges. The latter is especially important for modules like SIM plugs.
The taper angle facing away from the detachable module is preferably larger than the taper angle facing the module and should be more than 8 degrees, preferably more than 10 degrees and most preferably more than 12 degrees.
Generally, the taper angles should not be chosen too small. The reason is that for very small taper angles, the polymer that forms the optical disc with detachable module after hardening may have contracted so much around the line restrictor during the hardening process that the optical disc with detachable module cannot be removed from the mould without receiving gratings in the groove for the breaking line. Because the taper angle towards the module, especially when this module is a SIM plug has to be rather small, it is preferred that the taper angle facing away from the module is rather large, for example 20-30 degrees. This way, while being steep towards the detachable module, for example a SIM plug, the line restrictor may be so blunt that the groove for the breaking may not fasten on the line restrictor.
In case that the line restrictor is not comprised by a plunger and the line restrictor instead is a non-movable feature of the mould form or of the insert in the mould form, the line restrictor should be blunt for another reason. In case that the taper angles towards the module and facing away from the module are small, the line restrictor will be sharp and thin as a knife edge. This again implies that the thin line restrictor may more easily be deformed when polymer under high pressure is passing the narrow passage between the line restrictor and the opposite side of the mould. Partly, this can be prevented by using very hard materials, as for instance tungsten carbide, however, steel may be desired as a material for the line restrictor by other reasons. Generally, the shape of the line restrictor may be designed in dependence of the viscosity of the polymer and the distance between the line restrictor and the opposite side of the mould cavity.
The method of production of an optical disc with detachable module may result in a product being an optical disc with a detachable SIM plug, and said optical disc with SIM plug having a length of approximately 85.6 mm and a width of approximately 54 mm, the SIM plug being placed on a position corresponding to ISO 7810 standard, a diagonal of the optical disc being at least 80 mm, and a skew edge of the SIM plug facing away from the optical disk.
The detachable module may be a SIM plug for telephones as described above, for example with GSM, GPRS or UMTS standard, but may also be a pay card to be installed into a mobile phone in order to be able to pay for goods or services with the mobile phone. Applications in connection with road pricing or intelligent surveillance of buildings or working machines are other possibilities. Alternatively, the detachable module is a general computer component, for example a memory type or processing unit type as ROM, RAM, or CPU.
The user may, thus access the data information of the optical disc in order to learn about the module and its installation. The data information on the optical disc may also comprise a company profile of the producer or distributor, software drivers necessary for the installation of the microelectronics module, computer programs, software packages necessary for Internet access from a mobile or stationary telephone, purchase contracts, licenses, television receiver codes, or any other relevant information for the user.
The invention will be explained in more detail in the following with reference to the drawings.
a shows a standard mould form 100 with a first 101 and second 102 mould section that can be moved—as indicated by arrows 103, 103′—relative to one another between an open and a closed position. In the closed position, as illustrated in
The first section 101 of the mould is shown in a head-on perspective In
In order to produce optical disks with detachable modules according to the invention, an insert 108, as shown in
Now, referring to
The insert 108 may comprise a line restrictor 110 for restricting the thickness of the optical disc 200 with detachable module 201 along at least one breaking line 202 between the optical disc 200 and the detachable module 201 as shown in
In
As shown in
Smaller sections of grooves for breaking lines may be provided, for example, as shown in
The frame 203 can be attached to the optical disk 200 with a number of bridges 302 as shown in
The line restrictor 110 may be provided as a wedge, as shown in
If the detachable module 201 and the optical disk 200 both are desired with steep edges, the embodiment of
Other examples for possible shapes for line restrictors are shown in
In
Limited by the placement of the modules 201, 201′ on
In
However, the shown embodiment on
If the placement of the SIM plug should not exactly correspond to the ISO 7810 standard, the SIM plug 201 may be placed at the edge as shown in
In case that the optical disc together with the detachable module shall correspond to the ISO 7810 standard with a length of 85.6 mm and a width of 53.9 mm, a certain embodiment as shown on
The placement of the SIM module 201 as shown in
The embodiment on
In the shown embodiments in
The possibility to read the information on the optical disk 201 before detachment of the microelectronics module 201, for example a SIM plug or another computer component, may be important for the user in case he wants to read the information in order to find out, whether he actually wishes to purchase the module 201. On the other hand, the possibility to read the information after detachment may be important for the user in case that the information is Important during the user's installation of the module 201, where the Installation can be a number of difficult steps.
Because the embodiment as shown on
It is possible to form optical disks 200 with a variety of different shapes, for example polygonal, star-shaped, or oval, which may be used to catch the attention of the user when the user is visiting a seller's place and has to chose among a number of offers.
A frame 203 as shown in
In
| Number | Date | Country | Kind |
|---|---|---|---|
| PA 2001 00297 | Feb 2001 | DK | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DK02/00122 | 2/22/2002 | WO | 1/6/2006 |
