Technical Field The invention related to a data carrier as well as to a method for manufacturing a data carrier.

Background Art Data carriers in the shape of CDs or CD-ROMs or in DVD format have been known for some time. Further- more, it has also been proposed to use such data carriers e. g. as business cards by providing them with rectangular shape and designing them such that they can be centered in a CD or DVD reader.

Furthermore, it has been proposed to provide such devices with semiconductor chips for storing addi- tional data, see e. g. DE 42 42 247.

Disclosure of the Invention Hence, it is a general object of the inven- tion to provide a data carrier of the type mentioned above that can be read reliably.

Now, in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the data

carrier is manifested by the features that it comprises a plastic body, at least one metal layer arranged in said plastic body carrying information encoded in CD or DVD format, a semiconductor chip arranged in said plastic body, a communication device for connecting said semicon- ductor chip with an external apparatus, and a balancing means for balancing an unbalance caused by said semicon- ductor chip.

The balancing means allows to read the data carrier with high rotational speed. Preferably, balancing is achieved by a counterweight that lies (in respect to the carrier's central opening) opposite to the semicon- ductor chip. Alternatively, the plastic body can be de- signed to be lighter on the side receiving the semicon- ductor chip, e. g. by setting back a corner on this side.

In another aspect of the invention, it is an object to provide a data carrier of the type mentioned initially that can be easily connected to reading appara- tus.

In this aspect of the invention, the data carrier comprises a plastic body, at least one metal layer arranged in said plastic body carrying information encoded in CD or DVD format, a semiconductor chip ar- ranged in said plastic body, and an antenna for connect- ing said semiconductor chip with an external apparatus.

By providing an antenna, the semiconductor chip can eas- ily be connected to a suitable transceiver. The antenna can e. g. be arranged on the surface of the plastic body, or it can be formed by the metal layer.

Alternatively, in this aspect of the inven- tion, the data carrier is manifested by comprising a plastic body, at least one metal layer arranged in said plastic body carrying information encoded in CD or DVD format, a semiconductor chip arranged in said plastic body, and contact pads connected to said semiconductor chip and arranged at an outside of said plastic body for connecting said semiconductor chip with an external appa-

ratus, wherein said contact pads are formed by said metal layer.

In another aspect of the invention, it is an object to provide a data carrier where the semiconductor chip does not affect production and/or capacity of the optical storage.

In this aspect, the data carrier comprises a plastic body, at least one metal layer arranged in said plastic body carrying information encoded in DVD format, a semiconductor chip arranged in said plastic body, a communication device for connecting said semiconductor chip with an external apparatus, wherein said data car- rier comprises two plastic layers, wherein said metal layer carrying information encoded in DVD format is ar- ranged in a first plastic layer and said semiconductor chip and said communication device are arranged in a sec- ond plastic layer.

By using the two layer geometry of a DVD and using the upper layer for the semiconductor chip, the lower layer can be used fully for optical storage. A typical thickness of the first plastic layer is 0.6 mm for compatibility with standard DVD readers. Preferably, the second plastic layer has a width of approximately 0.2 mm, such that both layers add up to the width of 0. 8 mm, corresponding to the standard ISO format for chip cards.

In yet another aspect of the invention, the object lies in providing a data carrier exploiting the advantages of the combination of the semiconductor chip and the optical storage.

In this aspect, the data carrier comprises a plastic body, at least one metal layer arranged in said plastic body carrying information encoded in CD or DVD format, a semiconductor chip arranged in said plastic body comprising a counter for counting a number of ac- cesses to said information, and a communication device for connecting said semiconductor chip with an external apparatus.

This provides the possibility of keeping track of the number of accesses to the optically stored data, e. g. for licensing and billing purposes. In par- ticular, the counter can be used to disable access to the optically stored information after a certain number of accesses. This is particularly efficient when the data on the disk is encrypted and the chip holds the keys for en- crypting it.

In yet a further aspect, the object lies in providing a data carrier that can be built easily.

In this aspect, the data carrier comprises a plastic body, at least one metal layer arranged in said plastic body carrying information encoded in CD or DVD format, an opening in said plastic body for receiving a spindle of a disk drive, an annular insert arranged in said plastic body around said opening, a semiconductor chip arranged in said annular insert, and a communication device arranged in said plastic body for connecting said semiconductor chip with an external apparatus.

By placing the chip in an annular insert, it can be mounted easily. At the same time, since it is close to the spindle, its unbalancing effect is small. If an antenna is arranged in the annular insert, all elec- tronic parts can be installed in one single step. Pref- erably, the inner diameter of the annular insert is larger than the inner diameter of the opening, i. e. the edge of the opening is formed by the plastic body. This simplifies centering and prevents the application of ra- dial forces to the annular insert.

In yet another aspect, it is an object to provide a data carrier that can be easily mounted in a disc reader.

In this aspect, the data carrier comprises a plastic body, and at least one metal layer arranged in said plastic body carrying information encoded in CD or DVD format and readable from a bottom side of said plas- tic body, wherein said plastic body comprises a step ar-

ranged at said bottom side separating a thinner outer section of said plastic body from a thicker inner section for positioning said data carrier in a tray of a CD or DVD reader.

The step provides a means for centering the data carrier on a corresponding recess in the tray of the reader. The inner section has the conventional thickness of a CD or a DVD layer of 1.2 mm or 0.6 mm, respectively.

The step is preferably arranged on a circle having a di- ameter of approximately 80 mm, corresponding to the outer diameter of a mini-CD, such that it aligns with the cor- responding recess for mini-CDs in the tray.

In a final aspect, it is an object to provide a method for producing data carriers of the type men- tioned initially in an efficient manner.

In this aspect, the method for producing a data carrier having a plastic body, at least one metal layer arranged in said plastic body carrying information encoded in CD or DVD format, and a semiconductor chip ar- ranged in said plastic body comprises the steps of pro- viding a matrix carrying said information encoded in a relief and comprising a projection, casting a first part of said plastic body against said matrix, coating a side of said first part of said plastic body shaped by said matrix with metal for forming said metal layer, and coat- ing said metal layer with a second part of said plastic body, wherein a recess is formed in said plastic body by said projection and wherein said semiconductor chip (7) is inserted into said recess.

This method allows to prepare the plastic body in substantially conventional manner and to position the semiconductor chip after the casting of the first part of the body.

The data carrier according to the present in- vention can e. g. be used as identity card, credit card, business card or driver's license. It can also be used as

a data carrier for film and video data or for computer programs.

In particular, the data carrier can also be used for storing protected information. Based on the data stored in the semiconductor chip, it can be determined if the reader is authorized to access the data. For this purpose, the semiconductor chip can be provided with a decryption key or a credit counter.

Brief Description of the Drawings The invention will be better understood and objects other than those set forth above will become ap- parent when consideration is given to the following de- tailed description thereof. Such description makes refer- ence to the annexed drawings, wherein: Fig. 1 is a top view of a first embodiment of the data carrier according to the invention, Fig. 2 is a section along line II-II of Fig.

1, Fig. 3 is a view of the data carrier from be- low, Fig. 4 is an enlarged part of Fig. 2, Fig. 5 is a matrix, i. e. part of a casting mold, for producing the data carrier, Fig. 6 is a section along line VI-VI of the matrix or mold of Fig. 5, Fig. 7 is a second embodiment of the data carrier with an antenna, Fig. 8 is a third embodiment of the data car- rier, Fig. 9 is a fourth embodiment of the data carrier, Fig 10 is a section along line X-X of Fig. 9, Fig. 11 is a reader for encrypted data,

Fig. 12 is a possible embodiment of the semi- conductor chip when being used as data key, Fig. 13 is an alternative to the embodiment of Fig. 4, and Fig. 14 is an embodiment of the invention for a data carrier in DVD5-format.

Modes for Carrying Out the Invention A preferred embodiment of the data carrier according to the present invention is shown in Figs. 1- 3. It comprises a transparent plastic body 1, which is substantially rectangular in this embodiment. A metal layer 2 is arranged in plastic body 1, which carries in- formation in the CD or DVD format. An opening 3 is pro- vided at the center of plastic body 1 for receiving the spindle of a CD or DVD reader. A step 4 is arranged along a circle at the bottom side of the data carrier and sepa- rates a thinner, outer section 5 from a thicker inner section 6. The information on metal layer 2 is arranged in the inner section. In the inner section 6, the data carrier has the thickness of a conventional CD or DVD disk, such that the metal layer 2 can be read in conven- tional manner from below. The step 4 allows to position the data carrier in the tray of a CD or DVD reader. It is required in the present embodiment because the circumfer- ence of the data carrier does not correspond to the one of a conventional CD or DVD.

If the information is stored in CD format, the thickness of the inner section 6 is 1.2 mm. If the information is stored in DVD format, the thickness of the inner section 6 is approximately 0.6 mm (if only one metal layer is provided) or 1.2 mm (if two metal layers are provided).

The diameter of the circle the step 4 follows is 80 mm, i. e. it corresponds to the outer diameter of a

mini-CD and finds room in the mini-CD recess of a reader's tray.

A semiconductor chip 7, such as it is e. g. found in conventional chip cards, is arranged in a corner section of plastic body 1. Depending on the desired ap- plication, semiconductor chip 7 can be a passive, non- volatile memory or a microprocessor with its own control program. Semiconductor chip 7 is connected to contact pads 8 arranged on the surface of data carrier 1. They are used for connecting semiconductor chip 7 with an ex- ternal apparatus, in particular an external reader. Pref- erably, the arrangement of the contact pads 8 and elec- trical properties of semiconductor chip 7 correspond to conventional standards such as they are used for chip cards.

Usually, the density of semiconductor chip 7 is higher than the density of plastic body 1, which leads to a asymmetric distribution of the mass in the data car- rier. This might lead to unbalanced operation while ro- tating the data carrier about opening 3, in particular in high speed CD and DVD readers. Therefore, a counterweight 9 is arranged in a corner opposite to semiconductor chip 7. Counterweight 9 is also embedded in plastic body 1.

The weight and volume of counterweight 9 is chosen such that the unbalance caused by semiconductor chip 7 upon rotation about opening 3 is compensated.

Fig. 4 shows a detailed sectional view of the data carrier in the area of semiconductor chip 7. Plastic body 1 consists of a lower part la and an upper part lb with metal layer 2 arranged between them. Semiconductor chip 7 lies in a recess in lower part la and its surface is approximately at the height of metal layer 2. Metal layer 2 may or may not extend into the area of semicon- ductor chip 7. The contacts 8 are touching semiconductor chip 7 from above.

For manufacturing the data carrier of Figs. 1 -4, a matrix 10 is prepared first, as shown in Figs. 5

and 6. Matrix 10 comprises a surface 11 carrying a relief corresponding to the negative relief to be formed in metal layer 2. Furthermore, matrix 10 comprises a central projection 12 for creating opening 3. It further com- prises two smaller projections 13,14 at the positions of semiconductor chip 7 and counterweight 9.

During production of the data carrier, matrix 10 is pressed against a suited counter mold and the room between both molds is filled with plastic material, pref- erably a polycarbonate, which is hardened to form lower part la of plastic body 1. The projections 13,14 form recesses for receiving and positioning semiconductor chip 7 and counterweight 9.

After hardening first part la of plastic body 1, it is removed from the mold and coated with metal layer 2, preferably aluminum or gold, on its top surface, e. g. by sputtering. Then, semiconductor chip 7 and coun- terweight 9 are inserted into the recesses of lower part la of plastic body 1, whereby they are automatically po- sitioned correctly. Now, the contacts 8 are connected to semiconductor chip 7. Finally, upper part lb is formed by depositing a hardening lacquer. In a last step, the sur- face of the data carrier can be provided with a suited print 15 (Fig. 1).

Fig. 13 shows an alternative embodiment of a semiconductor chip 7 with contacts 8, which can be pro- duced in very simple manner using the method described above. Here, the contacts 8 are formed by structures ar- ranged in metal layer 2. For this purpose, a suited mask is laid over lower part la of plastic body 1 during de- positing the metal layer, such that the metal layer forms different, mutually isolated strips that extend to the bottom of recess 29. Then, semiconductor chip 7 is in- serted into recess 29 with its contacts facing down to contact the strips of metal layer 2. Then, semiconductor chip 7 is covered by a lacquer layer 30.

If the embodiment of Fig. 13 is used, metal layer 2 is preferably made from a corrosion resistant ma- terial, in particular gold.

Generally, strip conductors of any required shape can be formed in metal layer 2 and connected to semiconductor chip 7, such as power supply strips, an- tenna strips or strips connecting semiconductor chip 7 to contact pads.

In the embodiments described so far, contacts 8 were provided for connecting semiconductor chip 7 with an external reader. Alternatively, or in addition to this, an antenna can be provided, as it is e. g. shown in Fig. 7.

In the embodiment of Fig. 7, where metal layer 2 is shown as a gray shaded area, the antenna con- sists of two strips 16 formed in metal layer 2. In con- trast to conventional CDs or DVDs, metal layer 2 is therefore not one single, continuous layer extending over the whole disk, but is divided into mutually isolated re- gions to form the strips 16 separated by isolating areas 17. The strips 16 run along the edge of plastic body 1 for enclosing an as large area as possible and for mini- mizing a reduction of the readable area in CD or DVD for- mat. The strips 16 end at semiconductor chip 7 and are electrically connected to the same, e. g. in the manner shown in Fig. 13.

Semiconductor chip 7 can be connected wire- lessly with an external apparatus by means of antenna 16.

The external apparatus can e. g. be a device for ticket control or for testing an access authorization.

Antenna 16 can be used in conventional manner for data transfer, but also for supplying electric energy to semiconductor chip 7.

In the embodiment of Fig. 7, antenna 16 is formed in metal layer 2. It is however, also possible to arrange antenna 16 at the surface of the data carrier, e. g. by applying conducting strips, in particular using a

printing method, e. g. screen printing an electrically conducting paint.

Fig. 14 shows how semiconductor chip 7 and, if desired, an antenna 16 can be arranged in data carri- ers in DVD5 format. In such data carriers, plastic body 1 consists of two plastic layers 1', 1", wherein only lower plastic layer 1'is provided with a metal layer 2 with readable information. Upper plastic layer 1"is required for increasing the thickness of the data carrier. In a preferred embodiment, semiconductor 7, and, if provided, antenna 16, are arranged in upper plastic layer 1". Upper plastic layer 1"provides more room for the electronic components, and the storage capacity of the data carrier is not impaired.

In conventional DVDs, lower and upper plastic layer 1', 1"both have a thickness of 0.6 mm. In a pre- ferred embodiment of the present invention, however, up- per plastic layer 1"has a thickness of approximately 0.2 mm only so that the total thickness of the carrier is 0.8, corresponding to the thickness of chip cards accord- ing to ISO standard.

The strips 16 of Fig. 7 can be prepared by adding a suitable mask for covering the isolating areas 17 when depositing metal layer 2. Alternatively, the iso- lating areas can be etched off after depositing metal layer 2.

In the embodiments of Figs. 1 and 5, a coun- terweight 9 is provided for compensating an unbalance caused by semiconductor chip 7 (and contact pads 8). Fig.

8 shows an embodiment where this compensation is achieved by an asymmetric design of plastic body 1. Plastic body 1 is still essentially rectangular having four corners, but one corner 18 close to semiconductor chip 7 is more rounded and therefore set back.

In another embodiment opening 3 can be slightly offset from the center of plastic body 1 towards semiconductor chip 7 for achieving the same effect.

Figs. 9 and 10 show a further embodiment of the data carrier. Here, a recess is formed in the top surface of plastic body 1, and an annular insert 20 is placed therein. Insert 20 is preferably manufactured separately and comprises semiconductor chip 7 and annular antenna 16.

The inner diameter Dl of insert 20 is slightly larger than the one of opening 3, such that the position of the data carrier on the drive's spindle is defined by plastic body 1. This reduces the requirements regarding positional precision and size tolerance of an- nular insert 20.

The embodiment of Fig. 9 is easy to manufac- ture because insert 20 can be prepared separately and be inserted into plastic body 1 in one step. For preparing the recess for the annular insert, a suited projection is provided in matrix 10, similar to Fig. 6.

Due to the arrangement of the semiconductor chip 7 close to the axis of rotation of the data carrier, the embodiment of Fig. 9 requires no counterweight.

The embodiments of the data carrier shown here have the approximate size of a business or credit card. Depending on application, other sizes and shapes can be used. In particular, the data carrier can also have regular CD or DVD size.

As mentioned above, the data carrier can e. g. be used as a driver's license, a credit card, an identity card or a business card, but it can also be used in con- ventional manner as storage for films or video data, etc.

Company information, time tables, user manuals, applica- tion programs, music, films, etc. can be stored on metal layer 2 in DVD or CD format. Semiconductor chip 7 can e. g. be used for checking the card at gates, teller ma- chines, etc, or for determining an authorization for ac- cessing the stored data.

Semiconductor chip 7 can control the reading of the data in metal layer 2. In a preferred embodiment,

at least part of the data on metal layer 2 is stored in encrypted form. A key and/or a program for decryption is stored on semiconductor chip 7.

Fig. 11 shows a possible design of a device for reading data carriers with encrypted information. It comprises a reader 30 for CDs, or DVDs. Further, it com- prises a communication apparatus 31 for communicating with semiconductor chip 7, preferably in wireless manner with an antenna 16 as it is shown in Figs. 7,9 or 10. A block diagram of a corresponding semiconductor chip 7 is shown in Fig. 12.

At the beginning of a read operation, a read signal is sent to semiconductor chip 7 by means of commu- nication apparatus 31. Semiconductor chip 7 first tests a counter 32. If the value of counter 32 is not zero, it is decremented by one and a key stored in a key memory 33 is returned. If the value of counter 32 is zero, the key is not returned.

The key is transmitted from communication ap- paratus 31 to a decryption unit 34. At the same time, CD/DVD reader 30 starts reading the data in metal layer 2. At least part of the data stored therein is encrypted, and it is decrypted by decryption unit 34 using the key provided by semiconductor chip 7.

Counter 32 can be reloaded, i. e. be set to a value larger than zero, by means of a dedicated appara- tus.

The system of Figs 11 and 12 is especially suited for a data carrier the contents of which can only be read for a fee. The fee is paid at a point of sale, which sets counter 32 to a number corresponding to the permitted number of read operations. Then, for each read- ing of the data on metal layer 2, counter 32 is decre- mented until the permitted number of read operations is reached. Such a system can e. g. be used for rental of video or audio data.

In other words, semiconductor chip 7 is de- signed for disabling access to the stored information af- ter a certain number of accesses to the information.

Encryption in the context of the present in- vention designates measures that make accessing the data (or part thereof) stored in metal layer 2 difficult, such as e. g. a binary encryption of the data or a scrambling of the data, etc.

It is also possible to provide semiconductor chip 7 with a counter 32 only. In this case, the reading apparatus is designed such that it only reads the pro- tected data on the metal layer when the counter is not zero, decrementing the counter during each read opera- tion. Preferably, the protected data on metal layer 2 are encrypted such that reading in conventional devices is impossible. The key for decrypting the data is either stored in the reading apparatus or on metal layer 2.

Semiconductor chip 7 can also be used as an anti copying device because conventional writing appara- tus for DVDs and CDs can only copy the data on metal layer 2 but not the data stored in semiconductor chip 7.

Generally, in this embodiment, protected in- formation is stored on metal layer 2. Before reading, semiconductor chip 7 is read for detecting if the reader is authorized for reading the data.

While there are shown and described presently preferred embodiments of the invention, it is to be dis- tinctly understood that the invention is not limited thereto but may be otherwise variously embodied and prac- ticed within the scope of the following claims.