1 MEMORY CARD WITH IMPROVED OUTER STRUCTURE
FIELD OF THE INVENTION
The present invention relates generally to a memory card having an extremely high memory capacity, and particularly to such a memory card with novel outer structure that improves stiffness and magnetic properties
BACKGROUND OF THE INVENTION
There is a standard size card known as an ISO (International Standards
Organization) ID-1 card, having standard dimensions of 85 6 (± 12) mm in length, 53 98
(± 06) mm in width, and 0 76 (± 08) mm in thickness (ISO 7810 and 7813) Cards of the ISO ID-1 size are extensively used in a variety of applications, including credit cards, debit cards, identity cards, loyalty cards and access control cards, for example All these applications require a storage medium for storing user information
Presently the major storage media include a magnetic stripe on the surface of the card with 200 bytes of memory, or an electronic integrated circuit embedded on the card with up to 16 kilobytes of memory
In order to increase available memory storage capability, a memory card with
ISO ID-1 dimensions may be employed Such a memory card is described in PCT published patent application WO 97/21219, assigned to the present assignee, the disclosure of which is incorporated herein by reference. The WO 97/21219 memory card has a very high memory storage capacity Memory cards are widely used for recording various types of information to be read by a reader when inserted into the reader Such readers are associated with personal computers and dedicated computer systems
The stiffness of plastic cards used in the abovementioned credit or identification purposes and the like, is defined in certain international specifications, such as ISO 7810, section 8 1 1 and ISO 10373, section 5 12 For example, ISO 10373, section 5 12 defines the required stiffness as follows The card is clamped along one of its short edges, leaving the rest of the card cantilevered for a length of about 83 mm A force of 0 7 N applied to the opposite, free short end should deflect the free end of the card no more than 35 mm
It would be desirable to construct the ISO ID-1 memory card with a stiffness in accordance with such international specifications It is quite straightforward to construct standard credit cards and the like with almost any desired stiffness However, it is not obvious or straightforward to construct the ISO ID-1 memory card with such a stiffness, due to, inter
aha, the presence of internal components, weight and dimensional considerations, and economic factors
SUMMARY OF THE INVENTION
The present invention seeks to provide a novel memory card with a stiffness as defined in international specifications, such as ISO 7810, section 8 1 1 and ISO 10373, section
5 12 The present invention is particularly suitable for the ISO ID-1 memory card as described in WO 97/21219, although the present invention can be carried out with other memory cards as well
There is thus provided in accordance with a preferred embodiment of the present invention a memory card including a base sheet formed with a circular opening therethrough configured to accommodate a circular memory disc, a circular memory disc rotatably mounted within the circular opening, and a pair of cover sheets overlying opposite faces of the base sheet and rotatably mounting the circular memory disc between them, at least one of the cover sheets being formed with a window opening aligned with a Read section of the respective face of the circular memory disc, characterized by the cover sheets being constructed of a metal having a Young's modulus of at least 60,000 MPa approximately.
In accordance with a preferred embodiment of the present invention a non-structural non-metallic layer is applied on an outer surface of each cover sheet. For example, the outer surface of each cover sheet may be coated with the non-structural non-metallic layer.
Further in accordance with a preferred embodiment of the present invention the metal may include a spring steel, a non-magnetic steel, or spring phosphor bronze, for example.
Alternatively, in accordance with another preferred embodiment of the present invention, the metal may include a magnetic metal, a ferritic stainless steel, a martensitic stainless steel, Mumetal or a 30% Ni-Fe alloy, for example.
In accordance with a preferred embodiment of the present invention the non-structural non-metallic layer has a design applied thereon.
BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:
Fig 1 is a simplified, exploded, pictorial illustration of a memory card constructed and operative in accordance with a preferred embodiment of the present invention; and
Fig 2 is a simplified sectional illustration of a cover sheet of the memory card of Fig 1, constructed and operative in accordance with a preferred embodiment of the present invention
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Reference is now made to Fig 1 which illustrates a memory card 10 constructed and operative in accordance with a preferred embodiment of the present invention
Memory card 10 is preferably constructed basically as described in WO
97/21219, and is of the above-mentioned ISO ID-1 size The basic structure includes a base sheet 2, a memory disc 3 (preferably circular) rotatably mounted within the base sheet, a movable protective window assembly (not seen in Fig. 1), a pair of cover sheets 5 and 6 overlying the opposite faces of the base sheet 2 and the circular memory disc 3 therein, and a pair of liner discs 7 and 8 interposed between the cover sheets 5 and 6, and the respective face of the circular memory disc 3
The base sheet 2 is preferably made of stiff plastic material, and formed with a central circular opening 21 configured to accommodate the circular memory disc 3 Base sheet 2 is further formed with a lateral opening 22, including a section 23 communicating with circular opening 21, another section 24 leading to the edge of the base sheet, and a juncture section 25 between sections 23 and 24
In Fig 1, the base sheet 2 and the cover sheets 5 and 6 are shown as separate elements which are joined in the assembly process
The circular memory disc 3 may have the structure of a conventional magnetic diskette or floppy disc, but of smaller diameter, capable of recording and reading information from either side. It includes a central hub 31 for rotatably mounting the disc between the two cover sheets 5 and 6 Hub 31 is preferably formed with a central opening 32 for rotatably mounting the circular memory disc 3, and with a small eccentric opening 33 engageable with a rotary drive element of a card reader (not shown) for rotating the memory disc 3. Disc 3 is also preferably formed with a central opening 34 and an eccentric opening 35 both in alignment with openings 32 and 33, respectively, of its hub 31
The memory disc 3 may consist of flexible plastic film coated with a sensitive magnetic surface. Except for size, the magnetic discs may be identical to the magnetic discs used for memory storage in the 3 5" and 5 25" cartridges of personal computers Other memory discs could have magneto-optical surfaces or an ablative surface storage medium.
Each of the two outer cover sheets 5 and 6 preferably includes a central opening 51, 61, respectively, for rotatably mounting the circular memory disc 3, and a rectangular window 52, 62, respectively, laterally of the mounting opening 51, 61, so as to be alignable with a Read section of the circular memory disc 3 Central opening 61 of the lower cover sheet 6 is of larger diameter than central opening 51 in cover sheet 5, in order to expose eccentric opening 33 of the memory disc hub 31, and to thereby enable a rotary drive element of the reader (not shown) to be received within eccentric openings 33 in hub 31 and 35 in memory disc 3
The two liner discs 7 and 8, space the two cover sheets 5 and 6, from the respective faces of the circular memory disc 3 These liner discs, which may be made of paper but are preferably made of a non-woven fabric, are formed with a central opening 71, 81, respectively, for accommodating hub 31 of the memory disc 3, and with rectangular slots 72, 82, respectively, aligned with the rectangular window openings 52, 62, respectively, in the cover sheets 5, 6, respectively, to expose the Read section of the memory disc 3 to the Read head of the reader (not shown)
The present inventors have determined that the overall stiffness of the memory card 10 is mostly a function of the stiffness of cover sheets 5 and 6 The stiffness imparted to card 10 by base sheet 2 is small and negligible due to opening 21 and cut out sections 23 and 24 The present inventors solve the problem of constructing the ISO ID-1 card with the requisite stiffness by constructing cover sheets 5 and 6 of a metal 28 having a Young's modulus (i e , modulus of elasticity in tension) of at least 60,000 MPa approximately For example, cover sheets 5 and 6 may be made of a hardened steel with a thickness of 0 1-0 15 mm, most preferably 0 11-0 13 mm In such a manner, the ISO ID-1 memory card meets the stiffness requirements of ISO 7810, section 8 1 1 and ISO 10373, section 5.12 Preferred metals include non-magnetic steels, such as austenitic stainless steels (e g., AISI 301, 302, 303, 316, for example), manganese steel (approximately 88% Fe, 12% Mn) or spring phosphor bronze Aluminum alloys of the 5000 and 6000 series also have a Young's modulus of about 70,000 MPa These metals will not activate metal detector systems which detect distortions in magnetic fields
Alternatively, metal 28 may have magnetic properties in order to provide EMI/EMF protection Such an embodiment would be useful to protect the data magnetically stored on memory disc 3 from being inadvertently erased in the presence of electromagnetic
fields Preferred metals for such applications include ferritic stainless steels (e g , AISI 430 or 434), martensitic stainless steels (e g , AISI 431 or 440A-C), Mumetal (14% Fe, 5% Cu, 1 5% Cr, rest Ni) and 30% Ni-Fe alloys, which have relatively high magnetic permeability
In order to impart a pleasing plastic feel to the outer surface of memory card 10, a non-structural non-metallic layer 30, such as a plastic layer, is applied on an outer surface of metal 28, such as by coating, as seen in Fig 2 Non-structural non-metallic layer 30 can have a design 32 applied thereon, such as a graphic design, printed design, embossed design, silk-screened design and the like
It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove Rather the scope of the present invention includes both combinations and subcombinations of the features described hereinabove as well as modifications and variations thereof which would occur to a person of skill in the art upon reading the foregoing description and which are not in the prior art