Technical Field The invention relates to a case for storing two or more substantially flat storage me- dia such as CDs, CD-ROMs, DVDs, diskettes and the like, said case including at least two panels interconnected along a fold line such that they may be folded over upon each other, and where at least two panels each has at least one holder member for retaining a storage medium.

Background Art It is known to provide articles to be kept under surveillance with a transmitter emit- ting an electronically stored identification code, which can be read wirelessly by means of electronic reading equipment. The identification code may be stored in a chip connected to a coil acting as an antenna. Examples of special types of such transmitters are the so-called RF tags or radio frequency identification tags ("RF tags"or"RFID tags") shaped as flat labels or stickers. These tags are inter alia used in libraries, where each book, CD, DVD or the like is provided with a RFID tag, which is read and registered electronically at lending. It is also known to provide luggage with these RFID tags in airports to ease the luggage handling. RFDI tags are usually formed as passive transponders emitting a reply signal in reply to a received electromagnetic radio signal. A passive transponder may draw energy from the elec- tromagnetic field and is activated to emit an identification code, which can be read by means of the electronic reading equipment.

From WO 01/57794 A1 and US 6.044. 046 it is known to provide a CD with a trans- ponder in form of a chip with an identification code and a coil acting as resonant cir- cuit/antenna and disposed about the centre hole of the CD such that the balancing of the CD is not upset. As a result the individual CD may be read and registered when sold in a shop or at lent from a library. The transponder also serves as an anti-theft

device, a transceiver activating the transponder and emitting an alarm signal at the shop exit or library exit, if the transponder has not been deactivated at the cash regis- ter or the check-out counter.

CDs, CD-ROMs, DVDs and the like are often stored in a casing and by placing the transponder in the casing instead of on the CD per se, a lender or buyer wishing to steal the CD would merely remove the CD from the casing and pass through the exit without setting off the alarm system. For optimum security and for easy replacement of a worn or damaged casing it is thus advantageous to provide the storage medium per se instead of the casing with a transponder.

As mentioned above the antenna of the transmitter is usually formed as a coil placed around the centre hole of the CD so as not to upset the balancing of the CD. When rotating in the drive of a read/playback device a CD or DVD, which has an asym- metrical mass distribution, would subject the drive to dynamic loads and cause a di- sadvantageous heavy wearing thereof and possibly a damage thereto. The coil per se may be circular or square.

If two CDs or DVDs with identical transmitters are stacked, the reading equipment may have difficulty in reading both CDs, as one transmitter"shields"the other. This is particular problem when circular antenna coils placed around the hole of the CD are used. In a casing having two panels, which each retains a CD in such a manner that the two CDs are slightly interspaced and have a common centre in the folded state of the casing; the two antenna coils are located opposite one another and thus shield one another. If CDs having square, ie rectangular or quadratic, antenna coils are used these coils may be rotationally displaced in relation to each other so as to not shield each other 100%, but the individual CDs have to be placed with care in the casing in order to facilitate this. Even if the coils do not shield one another 100%, the coils partially overlap each other and impede a strong signal, which the transceiver would definitely be able to read.

A plurality of different containers for storing one or more storage media, especially CDs, is known.

ES 2143387 discloses a case for storing DVDs, in which a first panel is provided with holder members for retaining three DVDs such that these partially overlap each other. A second panel, which along a back portion is hinged to the first panel, may be folded over into abutment with the first panel for closure of the case. The DVDs stored in the case have no common centre, and antenna coils on the DVDs are thus offset in relation to each other, whereby each of them probably can be read in the folded state of the case. If the reading equipment for some reason has difficulty in reading the individual DVDs due to their close mutual positions, one or more of the DVDs has/have to be-either partially or completely-taken out of the case to obtain an electronic reading, which is both inconvenient and time-consuming.

GB 2.187. 442 A discloses a CD box, in which a first part includes holder members for retaining two juxtaposed CDs, and in which a second part being hinged to the first panel along a back portion can be folded over upon the first part for closure of the box. If provided with transmitters, the two CDs contained in this box can be read without any problems. The box is, however, not very compact and in practice of the same size as two juxtaposed CD casings.

WO 95/26917 discloses a CD container with two mutually hinged sections for stor- ing four CDs, each section being provided pockets to hold two CDs in a mutually overlapping position. When CDs are stored in all four pockets, two CDs in pairs have the same centre and thus make electronic reading of CDs with transmitters dif- ficult.

Description of the Invention The object of the invention is to provide a case for storing one or more storage me- dia, said case being compact at the same time as the individual storage media, which

may be provided with electronic transmitters, are individually detectable in the com- pact state of the case.

According to the invention the object is obtained in that the holder members are thus positioned on the panels that the retained storage media are offset in relation to each other in the folded state of the case. In addition to obtaining a compact case, a reli- able, non-contact reading of the identification code of the individual CDs in the folded state of the case is also obtained.

According to an advantageous embodiment each panel includes a holder member for a single storage medium. Should the non-contact electronic reading fail, eg due to electromagnetic interference, damage to the antenna coil or the like, the panels are merely unfolded from their folded state, whereby a reliable reading can be per- formed. It is thus not necessary to remove the storage media from the holder mem- bers.

According to an embodiment the panels may be made of a transparent material, whereby the storage medium is visible and any information printed on the storage medium is easily read.

According to an advantageous embodiment the holder members are formed of pock- ets, whereby a simple and reliable retainment is obtained in a simple and inexpen- sive manner.

The pockets are preferably made of a transparent material, in particular flexible plas- tics, eg polypropylene.

According to an embodiment the case may include a central panel being connected to a further panel along two, three or four side edges via fold lines. In such a case a single panel may be unfolded for removal or insertion of the storage medium with-

out having to unfold the other panels. The case may furthermore be completely un- folded without the need of a base with large dimensions in one direction.

According to an optional embodiment the case may include three or more consecu- tive panels being mutually foldable along parallel fold lines. Such a structure is in- expensive and easy to manufacture.

According to a preferred embodiment adjacent the holder member for the storage medium one or more of the individual panels may include a receiving member, eg a pocket, for a printed insert sheet or booklet. As a result the area of the panel, which is not covered by the storage medium, may be used effectively due to the differing positions of the CDs on the individual panels. The insert sheet or booklet may thus contain information about the storage medium retained in the respective panel.

According to a preferred embodiment the holder members are thus positioned on the panels that in the folded state of the case, the retained storage media are offset by 13 mm, preferably by 18 mm and most preferably by 23 mm in relation to each other in the plane of the panels. Tests have shown that a reliable reading of each storage me- dium is obtained thereby.

Brief Description of the Drawings The invention is explained in greater detail below by means of embodiments illus- trated in the drawings, in which Fig. 1 shows a CD provided with a transmitter having a circular antenna coil, Fig. 2 shows a CD provided with a transmitter having a rectangular antenna coil, Fig. 3 shows a first embodiment of the case according to the invention, two panels being shown unfolded,

Fig. 4 shows the same embodiment in its folded state, Fig. 5 shows another embodiment of a CD case according to the invention, three pa- nels being shown unfolded, Fig. 6 shows the same embodiment in its folded state, Fig. 7 shows a third embodiment of a case according to the invention, five panels being shown unfolded, Fig. 8 shows the same embodiment in its folded state, Fig. 9 shows a fourth embodiment of a case according to the invention, four panels being shown unfolded, and Fig. 10 shows the same embodiment in its folded state.

All figures are diagrammatic illustrations, details thus being omitted.

Best Mode (s) for carrying out the invention Fig. 1 is a diagrammatic view of a CD 1 with a centre hole 4 and a transmitter in- cluding a chip 5 and an antenna coil 3. In this Fig. the antenna coil 3 is only shown diagrammatically by means of hatching, but it includes a plurality of windings of an electrically conducting material connected to the chip 5. This type of transmitter is commonly known as a"RF tag" (Radio Frequency tag) or a RFID tag (Radio Fre- quency Identification tag) and is often integrated into a self-sealing label for easy fastening thereof on an article. In the present context the term"tag"or label is, how- ever, somewhat inaccurate in that the CD or another type of storage medium may be provided with the transmitter during manufacture, the transmitter for instance being

embedded in the plastic material from which the CD or DVD is made. The invention is furthermore not restricted to the use in connection with storage media, which are exclusively provided with radio frequency transmitters, but may for instance also be used in connection with storage media, which are provided with electromagnetic transmitters (EM tags/strips), which in more recent embodiments may be provided with an identification code.

RF transmitters may be passive, semi-passive or active. Passive RF transmitters ha- ve no built-in battery and receive their power from electromagnetic radio waves emitted by the electronic reader called a transceiver or interrogator. Passive RF transmitters can be made extremely small, are cost-effective to manufacture and ha- ve a long operating life. The draw-backs of passive RF transmitters are that they are comparatively sensitive to electromagnetic interference and have a fairly limited communication range. Semi-passive RF transmitters are provided with a built-in bat- tery, but communicate only by reflecting radio frequency energy. Semi-passive RF transmitters have greater communication ranges than passive RF transmitters and by means of a small battery they can operate for five to ten years. Active RF transmit- ters have a built-in battery and are able to initiate a communication sequence in con- trast to passive and semi-passive RF transmitters, which have to receive a signal from an interrogator, before returning a signal. Active RF transmitters have a fairly short operating life, if activated often, and are more expensive to manufacture than the two other types of transmitters.

The RF transmitter shown in Fig. 1 is a passive RF transmitter, as this type is par- ticularly suitable for CDs, DVDs and the like media due to its compact size. The chip and antenna coil of the RF transmitter may be glued to the surface of the CD or be embedded in the material. The transmitter shown in Fig. 1 is particularly advan- tageous in that the antenna coil is positioned outside the area provided with a metal layer, in which the CD's data is stored. The metal layer starts at the circle 2 and ex- tends to an area close to the periphery of the CD 1. Due to the co-axial position of the antenna coil 3 around the centre hole 4 of the CD, the CD has a completely

symmetrical mass distribution, whereby the drive of the CD player is not unduly loaded.

Fig. 2 illustrates a CD 1 having another embodiment of a RF transmitter, the antenna coil 3 here being rectangular. Due to symmetrical position of the antenna coil 3 around the centre hole 4, the CD with a transmitter has a symmetrical mass distribu- tion around the middle of the centre hole 4. The antenna coil 3 is arranged on the side of the CD, which is not read by the read head of the CD player so as not to shield the data stored on the CD. The embodiment shown in Fig. 2 has the draw- back in relation to the embodiment shown in Fig. 1 that the antenna coil overlaps the metal layer of the CD, but it is possible to compensate for this draw-back by using a sufficiently strong signal.

Fig. 3 illustrates a first embodiment of a case according to the invention. The case includes two panels 6,7, which can be folded over upon each other about a back portion or fold line 23. The CD case may advantageously be made of cardboard or plastic, in particular of transparent plastic, whereby the contents become visible.

Each panel 6,7 is provided with a pocket defined by the fold line 23, two outer edges of the case and an edge 24 extending across the panel. The pocket 8 may thus be fixedly attached to the panel along three edges and open at the fourth edge ex- tending across the edge 24 of the panel. As evident in Fig. 3, when the panel is folded over about the fold line 23, the pockets are arranged such on their respective panel 6,7 that they are staggered in relation to each other, as diagrammatically shown in Fig. 4. The two antenna coils 3 do thus not overlap one another, whereby a reliable reading of both CDs is enabled by means of an external transceiver. The pockets may most advantageously be made from transparent plastic to allow visibil- ity of the CDs in the open state of the case. The reverse side of the panels may also be provided with pockets of transparent plastic, in which a text sheet or booklet with information about contents stored on the CDs may be inserted. The areas 9 of the panels 6,7, which are not covered by the pockets 8, may also be provided with

pockets for insertion of text sheets or the like. The pocket 9 on each panel 6,7 may thus contain an information sheet about the CD stored in the respective panel.

Fig. 5 illustrates a second embodiment of a case according to the invention. This ca- se includes three panels 10,11, 13, which may be folded over upon each other about two fold lines 23. The case is shown in its folded state in Fig. 6, from which it ap- pears that the CDs are staggered in relation to each other such that the transmitter of each CD may be reliably read.

Fig. 7 illustrates a third embodiment of the invention adapted for storage of four CDs. The case shown in Fig. 7 thus includes a central panel 14 being connected with the panels 15,16, 17,18 at all of its four sides. The central panel 14 and the panels 15,16, 17 are provided with pockets for storing CDs, and the panel 18 is provided with a large pocket for storing for instance a booklet. In fig. 8 the panel shown in Fig. 7 is shown in its folded state and it is evident that the four CDs are staggered in relation to each other.

Fig. 9 is a diagrammatic view of a fourth embodiment of the invention for storing four CDs. The case includes four panels 19,20, 21,22, foldable over upon each other along parallel fold lines 23. The panels 19,20, 21,22 have the same size, but the individual pockets are placed at different positions on the individual panels such that the CDs stored in the pockets are staggered in relation to each other in the folded state of the case, as shown diagrammatically in Fig. 10. The pockets are lat- erally defined by the longitudinal sides of the panels. The pockets of the uppermost and lowermost panels shown in Fig. 9 are defined by a fold line 23 and a line 24 ex- tending transversely of the panel, while the pockets of the middle panels are defined by two transverse lines 24. The mouth of the pockets may be provided along any side and may for instance extend along the transverse lines 24. The embodiment shown in Figs. 9 and 10 has four panels, but may in principle be provided with an even larger number of panels. One or more of the panels may be provided with a pocket for a text sheet, a booklet or the like.

The case shown in Fig. 9 is provided with burr fasteners 26,27 on the two lower- most panels for retaining the panel in its closed position. Other types of fasteners, such as snap fasteners may of course also be used.

The embodiments described above relate to CD cases, but the invention is not re- stricted to the storage of CDs. The case according to the invention may thus be used for storing CDs, DVDs, minidisks, diskettes, videotapes, laser discs, CD-ROMs and the like media. The crucial element is that the storage media are provided with transmitters arranged at the same position, for which reason a staggered positioning of the storage media in the closed state of the case is desired.

The case may typically be made by die-cutting, folding, welding or hobbing of sheet plastic, eg. polypropylene or the like. All of the shown embodiments may be made from a blank cut out of a sheet of material. The pockets may thus be provided by folding over"pocket panels"being sealed along three edges. The fold lines may qui- te simply be provided by for instance a suitable heat-treatment in the folded state of the case.

The invention relates to a case for storing storage media being provided with identi- fication transmitters in any given form. Different types of transmitters than the RF transmitters mentioned herein may be used, eg"AM tags" (acousto-magnetic tags) or other types of detectable components in systems for electronic article surveillance.

The CD case may be used in connection with systems, in which the transceiver is stationary and placed on a counter in a library, in a cash register in a shop or at the exit of the library/shop. A hand-held reader may also be used. Radio frequencies of 13.56 MHz are typically used and according to standards the effect of the reader must not exceed a specific value, typically 8-12 Watt.

A conventional CD has an outer diameter of 120 mm and a centre hole of a diameter of 15 mm. The data-carrying area, ie the area including the metal layer, typically aluminium, is located between a circle around the centre of a diameter of 46 mm and a circle of a diameter of 117 mm. By arranging the holder members of the panels such that the CDs are staggered in relation to each by 46 mm in the closed state of the case, any overlap between the RF transmitters according to the embodiment shown in Fig. 1 is prevented. Tests have, however, shown that a particularly reliable reading can be obtained at a displacement of about 23 mm In all of the above described embodiments, the flat storage media are substantially parallel to the panels when retained by the panels.

The phrase"offset in relation to each other"is to be construed as"staggered in a di- rection parallel to the planes of the panels in the folded state of the case". The phrase "offset/staggered in relation to each other"could also be expressed as"not being completely aligned".

In all embodiments having three or more panels, one of the panels may be without a holder member. As an example, the central panel of the embodiment shown in Fig. 6 may be without a holder member. The case may also be embodied as a"booklet" with three or more panels being interconnected by means of a common fold line or spine.