Pre-pack for a smart card, smart card and method of forming a pre-pack for a smart card

Abstract

When forming a smart card or a preform thereof, good process robustness and yield can be achieved by incorporating components such as display devices, etc., for example, by preparing a prepackage in a separate manner from the rest of the preform and subsequently inserting the prepackage into the preform.

Description

TECHNICAL FIELD

[0001] The present invention relates generally to any type of smart card, such as a credit card, a payment card, a key card, an electronic tag, a data page of a security document, etc., wherein the card-type substrate comprises electronic components for providing information and / or responding to external stimuli, etc. BACKGROUND

[0002] The use of smart cards of the type described above has evolved into a broad concept for handling sensitive information. In recent developments, not only the tamper resistance and good security of the information are important aspects, but also the incorporation of increasing functionality into the card-type substrate is considered essential in order to meet the many aspects of needs encountered in our complex society. For example, card-type substrates are increasingly used in the form of credit cards, payment cards, etc. for managing financial transactions. To this end, depending on the overall requirements associated with the particular environment in which the smart card is to be used, many types of smart cards have implemented more or less complex electronic components therein in order to endow the smart card with specific capabilities, such as responding to external stimuli, providing and / or handling sensitive information, providing a wireless connection, presenting information, providing a pleasing appearance, etc.

[0003] Basically, a smart card is generally composed of a plurality of material layers that are processed so as to form a substantially monolithic mass of material in which any corresponding electronic components have been incorporated, such as for example one or more antennas for endowing the smart card with RFID (Radio Frequency Identification) capabilities, electronic modules for storing and processing information, corresponding electrical connection networks, additional components for inductively and / or capacitively interconnecting the components inside the card, etc. As a result, a variety of techniques have been developed aiming at joining the various material layers so as to form a substantially monolithic mass of material while properly surrounding the relevant functional components. Due to the trend of incorporating additional functionality into smart cards, it can be necessary to integrate specific components in the form of discrete electronic components, optical components, power supply means, etc. into the smart card, thereby resulting in a significant additional complexity of the overall manufacturing process. For example, it can be necessary for the card manufacturer to be provided with a corresponding preform of the smart card that enables the incorporation of additional features, such as specific components, in order to provide a customized smart card with specific functionality. Many of these additional components have a substantially non-planar configuration, i.e. a configuration with an increased height dimension compared to the corresponding lateral dimensions of any such component, thereby requiring a significant amount of work to incorporate these components into the card-type substrate, especially if certain specifications have to be met. Due to the highly competitive market in this technical field, it can be necessary to incorporate the corresponding components based on an efficient mass production technique while ensuring a high level of integration with respect to the tamper resistance and robustness of the smart card in view of any environmental influences and mechanical stresses, in order to achieve the long service life required of any such smart card.

[0004] In a conventional approach, additional electronic components, such as display devices, are incorporated into a smart card typically by suitably preparing individual card layers, e.g. by forming respective openings in some layers and inserting respective components, i.e. integrated circuit chips and displays, and laminating the respective layers based on suitable process conditions. Thereafter, final process steps can be applied, e.g. by incorporating custom printed areas, giving the smart card a desired appearance, etc. These final process steps are typically performed by an end manufacturer based on a preform of the smart card, which has already incorporated the electronic chips and display devices therein. Thus, especially when manufacturing preforms of smart cards so as to include complex additional components, such as display devices, a highly complex process sequence has to be implemented, wherein especially the respective manufacturing tolerances associated with incorporating the display devices into the individual card layers can result in a reduced overall yield and / or reliability of the final smart card.

[0005] Thus, in view of the above, it is an object of the present application to provide increased flexibility in incorporating additional components into a preform of a smart card while eliminating or at least reducing one or more of the above-mentioned problems. SUMMARY

[0006] In view of the above technical problems, the present application is generally based on the concept that by separating the basic process of forming a preform of a smart card from the process of incorporating complex additional components, such as displays and / or batteries and / or keyboards and / or sensors and / or optical components, an increase in precision in manufacturing preforms of complex smart cards and thus corresponding final three-dimensional smart cards can be achieved. To this end, the prepackage is formed as a separate component based on lateral and height dimensions selected in correspondence with the components to be incorporated, without having to take into account the final dimensions and height dimensions of the preform of the smart card and the final smart card. Moreover, process steps for incorporating the respective components into the prepackage, such as parameters for a lamination process, can be specifically adapted to the additional components without substantially affecting other areas of the preform of the smart card. Thus, while still providing a high degree of consistency between the material of the prepackage and the actual preform of the smart card, the respective processes and materials can be specifically adapted to the requirements of the components to be incorporated and thus optimized thereto.

[0007] It should be noted that the term "smart card" as used in the present specification is to be understood as encompassing any type of card-shaped substrate comprising electronic components for providing information and / or responding to external stimuli. Specific embodiments of smart cards according to the foregoing definition include inter alia credit cards, payment cards, key cards, electronic tags, data pages of security documents such as electronic passports, etc.

[0008] According to an aspect of the present application, the above technical object is achieved by a pre-pack for a smart card. The pre-pack comprises a flexible printed circuit board comprising at least one non-planar circuit portion. The pre-pack further comprises a stack of material layers accommodating the flexible printed circuit board to provide a planar top surface and a bottom surface of the stack of material layers.

[0009] According to this configuration of the pre-pack, which is considered as a separate component at an early manufacturing stage of the corresponding smart card, the flexible printed circuit board is suitably shaped in a three-dimensional configuration in order to provide the at least one non-planar circuit portion. Accordingly, a respective complex component, such as a display, a battery, an optical component, a switch or a keyboard, etc. can be positioned within the at least one non-planar circuit portion, whereas the stack of material layers accommodating the flexible printed circuit board provides a planar top surface and a bottom surface, thereby facilitating further processing of the pre-pack, e.g. when incorporating the pre-pack into a respective pre-mold of a smart card.

[0010] In another illustrative embodiment, the pre-pack has a predetermined lateral dimension defined by the top surface and the bottom surface. That is, the lateral dimension of the pre-pack can be precisely determined based on the stack of material layers, i.e. based on its bottom surface and top surface, thereby achieving a high precision in determining the lateral outer dimension of the pre-pack, which in turn enables a precise incorporation into a pre-mold of a smart card, thereby significantly reducing any manufacturing tolerances that can typically be associated with incorporating complex electronic components into a smart card.

[0011] In another illustrative embodiment, the pre-pack has a height dimension, i.e. a dimension orthogonal to the lateral dimension, which has a value of less than 0.8 millimeters (mm). Thus, the pre-pack can be manufactured to fit the dimensions of many conventional smart cards without adding additional height or thickness to such cards. In particular, in embodiments, the thickness or height of the pre-pack can be about 0.6 millimeters or even less, thereby allowing the incorporation of the pre-pack into standard smart cards used as credit cards, payment cards, key cards, etc.

[0012] In another illustrative embodiment, at least one material forming part of the top surface and / or the bottom surface is a material also used for the smart card. Thus, in addition to the substantially planar surface configuration provided by the bottom surface and the top surface, the material composition of at least one of these surfaces or parts thereof also ensures a consistency with the materials and / or processes of the smart card and its respective pre-mold. Thus, as discussed above, a desired continuous material property between the pre-pack and the remaining parts of the smart card or pre-mold can be achieved when incorporating the pre-pack into the smart card or pre-mold.

[0013] In another illustrative embodiment, the material forming the portion of the top surface and / or the bottom surface comprises at least one of polyvinyl chloride (PVC) and polycarbonate and other materials typically used with smart cards. That is, at least a portion of the top surface and / or the bottom surface is formed from a material typically used for manufacturing smart cards, as discussed above. Thus, when providing the pre-packaging as a separate component of a smart card, the respective processing of the surface material, e.g. in the form of PVC or polycarbonate, can specifically be adapted to the requirements of the additional component, e.g. when selecting appropriate process parameters in terms of pressure, temperature and process duration during a lamination process, while the remaining parts of the respective smart card or pre-forms thereof can be processed based on different process conditions, if required.

[0014] In some illustrative embodiments, the flexible printed circuit board comprises a display and / or a keyboard and / or a sensor and / or a battery and / or an optical component and / or an electronic component. Thus, a required complexity of the respective smart card due to good functionality can be provided without being associated with respective process limitations that can be used when processing the smart card or pre-forms thereof as a whole, since the pre-packaging can be formed based on significantly smaller shape parameters and based on appropriately selected process parameters.

[0015] In another illustrative embodiment, the stack of layers comprises a frame layer surrounding at least a portion of the at least one non-planar circuit portion. By incorporating the frame layer, the respective components located in the non-planar circuit portion can be appropriately mechanically stabilized, while additionally a certain degree of leveling with respect to layers outside the non-planar circuit portion can be achieved. In this way, appropriate process parameters can be selected, e.g. in terms of mechanical pressure to be applied during a lamination process, without inappropriately affecting one or more components positioned within the non-planar circuit portion.

[0016] In another illustrative embodiment, the stack of material layers comprises a top layer forming at least a portion of the planar top surface and a bottom layer forming at least a portion of the planar bottom surface. In this case, the bottom and top layers of the stack of layers are selected to provide the planar surface areas without any further process steps, since the desired planar surface configuration can be obtained by the stack of layers itself, i.e. by the respective top and bottom layers.

[0017] In another illustrative embodiment, the top and / or bottom layer comprises a window portion aligned with at least a portion of the opening of the frame layer. That is, the frame layer laterally surrounding at least a portion of the non-planar circuit portion and thus at least a portion of the corresponding components positioned therein enables an “access” to the corresponding components by means of the window.

[0018] In this context, the term "access" is to be understood as describing any type of component interaction offer with the environment, for example by providing visibility, enabling direct or indirect mechanical or electrical contact, etc.

[0019] In another illustrative embodiment, the pre-packaging comprises a frame side wall structure laterally surrounding a central portion of the stack of material layers, wherein the frame side wall structure is laterally aligned with the top surface and the bottom surface to define a predetermined lateral dimension over the entire height direction of the pre-packaging. Thus, the frame side wall structure results in an effective lateral constraint of the non-flat circuit portion and thus of any components positioned therein, while also ensuring a precise lateral dimension throughout the overall height or thickness of the pre-packaging. Thus, the precisely defined lateral dimension over the entire overall thickness of the pre-packaging reduces overall process tolerances and enables a precise positioning of the pre-packaging within the smart card or its pre-form when further processing the pre-packaging, i.e. when incorporating the pre-packaging into the smart card or its pre-form.

[0020] According to another aspect of the present application, the above technical objects are achieved by a precursor sheet for forming a smart card. The precursor sheet comprises an array of pre-packagings having the above-mentioned characteristics. Additionally, the precursor sheet comprises a base material mechanically interconnecting the pre-packagings of the array. As already discussed above, the provision of a plurality of pre-packagings in the form of an array interconnected by the base material enables a very efficient overall processing of the pre-packagings, for example by cutting the pre-packagings and inserting the respective individual pre-packagings into a three-dimensional smart card or its pre-form.

[0021] In one illustrative embodiment, the precursor sheet is provided in the form of a web. Thus, the provision of the pre-packagings is realized in a highly space-saving manner, enabling the use of mass production techniques while still maintaining a high degree of process precision.

[0022] According to another aspect of the present application, the above objects are achieved by a smart card comprising a stack of card layers and a pre-packaging embedded into the stack of card layers and having the characteristics as discussed before. In this way, the pre-packaging having precisely defined lateral and height dimensions can be positioned with high precision within the stack of card layers as explained before, while additionally enabling the manufacturing of the smart card pre-form based on pre-form specific process conditions without affecting the manufacturing of the pre-packaging and thus the characteristics of the pre-packaging.

[0023] In another illustrative embodiment of the smart card, the stack of card layers includes a printed portion formed of a first material, wherein the pre-packaged portion positioned adjacent to the printed portion is formed of a second material having substantially the same thermal characteristics as the first material. That is, when forming the smart card based on the pre-packaging, as discussed above, the pre-packaging and the adjacent portion of the smart card can exhibit similar thermal characteristics, thereby at least ensuring consistency in the optical appearance between the adjacent portions when forming the printed area, etc., since, among other things, the thermal characteristics of the card material can have an impact on the ultimately obtained characteristics of the adjacent material area. In a preferred embodiment, the first and second materials are substantially the same in their basic chemical composition.

[0024] In one illustrative embodiment, the pre-packaging has a window, and the smart card includes a card window that is at least partially aligned with the window of the pre-packaging. In this manner, the non-planar circuit portion, and thus any components positioned therein, can be "accessed" by means of the card window and the window of the pre-packaging. It should be appreciated that the "access" of the non-planar circuit portion can include the presence of an optically transparent material in the card window when the visibility of at least a portion of the component is sufficient to "access" the component. In other cases, the window can not include any material if direct access to the inner layer of the smart card associated with the non-planar circuit portion is required.

[0025] According to another aspect of the present application, the above technical object is achieved by a method of forming a pre-packaging for a smart card. The method includes the step of providing an array of flexible printed circuit boards mechanically interconnected by a carrier material, wherein each of the flexible printed circuit boards includes at least one non-planar circuit portion. The method further includes the step of attaching the array of flexible printed circuit boards to a first layer of a smart card compatible material. Moreover, the method includes the step of laterally enclosing at least the non-planar circuit portion of each of the flexible printed circuit boards in the array by attaching a respective frame layer to the first layer for each of the non-planar circuit portions, wherein each of the frame layers has an opening so as to accommodate at least the respective non-planar circuit portion and so as to at least partially flatten the non-planarity of the respective non-planar circuit portion. Furthermore, the method includes the step of attaching a second layer formed of a smart card compatible material to the first layer to form a planar bottom surface. Finally, the method includes the step of attaching a third layer formed of a smart card compatible material to the frame layers to form a planar top surface. Thus, the method of the present application describes a technique for incorporating flexible printed circuit boards in a stack of material layers, providing at least the top and bottom layers of the stack of material layers in the form of a smart card compatible material. In this manner, the pre-packaging can be formed as a separate component as already discussed above, while still exhibiting material consistency with the desired smart card.

[0026] In another illustrative embodiment, the method comprises the step of pre-preparing the frame layer according to the lateral and height dimensions of the flexible printed circuit board. Thus, according to the design requirements, the frame layer is prepared so as to achieve lateral encircling and / or to act as a height levelling component and is manufactured in a separate process step without affecting the other components of the pre-pack.

[0027] In an additional illustrative embodiment, the array of flexible printed circuit boards is provided in the form of a web and the first, second and third layers formed of smart card compatible material are each provided in the form of a web. In this way, mass production techniques can be efficiently implemented while still achieving high precision in forming the pre-pack, which in turn translates directly into increased reliability and good process yield in forming smart cards based on the pre-pack, as also discussed above. BRIEF DESCRIPTION OF DRAWINGS

[0028] Other illustrative embodiments and aspects of the present application will be described in greater detail in the following specification, taken in conjunction with the accompanying drawings, in which:

[0029] Figure 1 schematically illustrates an exploded view of a pre-pack according to an illustrative embodiment,

[0030] Figure 2 schematically illustrates an exploded view of a pre-pack according to an illustrative embodiment, wherein the corresponding flexible printed circuit board is omitted,

[0031] Figure 3 schematically illustrates a top view of a plurality of pre-packs formed on a carrier material provided as a web according to an illustrative embodiment,

[0032] Figure 4 schematically illustrates a top view of a precursor sheet comprising a plurality of smart card pre-forms for receiving respective pre-packs, and

[0033] Figure 5A and Figure 5B schematically illustrates a top view and a cross-sectional view of a smart card comprising a pre-pack according to an illustrative embodiment. DETAILED DESCRIPTION

[0034] The present application will be described in more detail in the following specification, with reference to the accompanying drawings.

[0035] Figure 1An exploded cross-sectional view of a pre-packaging 100 according to an illustrative embodiment of the present application is schematically illustrated. As shown, the pre-packaging 100 comprises a flexible printed circuit board 110 having a substantially non-planar circuit portion 111, which is to be understood as a circuit portion whose substrate is elevated or recessed according to one's point of view, thereby forming a stepped configuration having a height 111H. The non-planar circuit portion 111 can comprise one or more components that are not easily integrated into a corresponding integrated circuit chip (not shown). The one or more integrated circuit chips can be comprised in or on the flexible printed circuit board 110, or can be positioned at any other suitable location within the pre-packaging 100. For example, the respective one or more circuit chips can be positioned on or in a material layer 122, 123, which can be suitably dimensioned and shaped to at least accommodate the non-planar circuit portion 111. Further, the flexible printed circuit board 110 can comprise suitable contact elements 113, which can be connected to respective counterparts (not shown) in one of the layers 123, 122, in order to establish a mechanical and electrical connection between the flexible printed circuit board 110 and the one or more circuit chips or any other substantially two-dimensional electronic components provided in the layer 123 and / or 122.

[0036] The non-planar circuit portion 111 can comprise any suitable components, such as a display and / or a keyboard or individual buttons and / or an energy storage, such as a battery and / or optical components, etc. Advantageously, the height 111H of the non-planar circuit portion 111 is selected such that the height dimension of the component 112 is at least partially compensated. Further, a frame layer 124 is positioned at one side of the component 112, which frame layer 124 has a lateral dimension corresponding to the non-planar circuit portion 111, so as to laterally enclose the component 112. Further, the frame layer 124 can comprise an opening 124W exposing at least a portion of the component 112. Thus, the frame layer 124 serves to laterally enclose and thus stabilize the component 112. The frame layer 124 can also serve to at least to some extent level the difference in height level between the component 112 and the planar portion of the flexible printed circuit board 110.

[0037] Furthermore, the pre-pack 100 comprises a top layer 121 having a top surface 121 S which is a substantially planar surface made of any suitable material. For example, the top layer 121 can be a smart card compatible material, for example in the form of PVC (polyvinyl chloride), polycarbonate, etc., which can be combined with a suitable coating (not shown) so as to facilitate the formation of a uniform material property between the pre-pack 100 and the corresponding smart card or pre-form thereof into which the pre-pack 100 will be inserted at a later manufacturing stage. Similarly, the pre-pack 100 comprises a bottom layer 125 which can also be a smart card compatible material which can be combined with a corresponding coating so as to provide uniformity of material properties in relation to the smart card or pre-form thereof. Furthermore, as discussed above, the bottom surface 125S of the layer 125 can be a substantially planar surface so as to ensure good processing when inserting the pre-pack into the smart card or pre-form thereof. In the illustrated embodiment, the bottom layer 125 comprises a window 125W which is aligned with the opening 124W of the frame layer 124 so as to provide access to at least a portion of the assembly 112, where the term "access" is to be understood in the sense defined above.

[0038] Thus, the pre-pack 100 comprises a stack of material layers 120 which includes a layer 121 providing a planar top surface 121 S, layers 122, 123 to be attached to the flexible printed circuit board 110, a frame layer 124 and a bottom layer 125 providing a planar bottom surface 125S, as discussed above. Furthermore, in the illustrated embodiment, the pre-pack 100 comprises a layer 127 of adhesive material which is provided between the bottom layer 125 and the frame layer 124. The layer 127 of adhesive material can be provided in the form of a PVC layer having a thickness of about 100 pm, for example. Figure 1 The lateral dimension, indicated in the figure as dimension 126 along one lateral direction, is precisely defined by the bottom surface 125S and the top surface 121 S, so that the lateral size and shape of the pre-pack 100 is defined in a precise manner so as to reduce inappropriate manufacturing tolerances when implementing the assembly 112 in the corresponding smart card or pre-form thereof.

[0039] Figure 2 An exploded cross-sectional view of a pre-pack 100 is schematically illustrated, in which the flexible printed circuit board 110 (see Figure 1 ) is omitted. As shown, the top surface 121 S can be provided in the form of a coating applied to the top layer 121, which in some illustrative embodiments is provided in the form of a PVC layer having a thickness of about 100 pm. Similarly, the bottom layer 125 is provided in the form of a PVC material having a thickness of about 100 pm, which is followed by a corresponding coating to form the bottom surface 125S.

[0040] It will be appreciated that the composition of the layers 121, 125 and their thicknesses are merely examples and that these solutions can be adapted to specific use cases.

[0041] Layers 122, 123 can be formed of any suitable material, such as a smart card compatible material in the form of PVC, polycarbonate, etc., with each of layers 122, 123 having a thickness of about 100 pm. Moreover, a coating 122A can be formed on the free surface of layer 122, while a free film having any suitable composition can be provided on the free surface of layer 123, for example in the form of an adhesive material or the like. Similarly, a free film in the form of an adhesive material can have been formed on the frame layer 124 so as to be connected to assembly 112 (see Figure 1 ), while the opposite surface of frame layer 124 can be covered by a suitable coating 124B to be connected to underlying layer 125.

[0042] In addition, in this case it should be understood that the composition of layers 122, 123, 124 and their thicknesses are merely examples, and these solutions can be adapted to specific use cases.

[0043] Moreover, a frame structure 127 can be provided so as to be laterally connected to layers 122, 123, with the height 128 of frame structure 127 being selected so as to correspond to the height and thickness of layers 122, 123 and the corresponding coating formed thereon, as well as to the thickness and height of flexible printed circuit board 110 including assembly 112 with frame layer 124 attached thereto (see Figure 1 ). For example, when pre-pack 100 is to be incorporated in a standard smart card to be used as a payment card of any type that can have to comply with the corresponding international standards, height dimension 128 can be in the range of about 300 pm to 350 pm. In other cases, height 128 can be adapted to the specific use case under consideration.

[0044] In the illustrative implementation, frame structure, for example formed of any suitable smart card compatible material such as PVC, polycarbonate, etc., can have a configuration such that the lateral dimension defined by top surface 121S and bottom surface 125S is continued along the entire height of pre-pack 100. Thus, the lateral dimension along the entire height or thickness of pre-pack 100 is precisely defined by surfaces 121S, 125S and the lateral dimension of frame structure 127.

[0045] Pre-pack 100 as shown in Figure 1 and Figure 2 may be formed on the basis of the following process.

[0046] The flexible printed circuit board 110 can typically be provided as a web and can be appropriately imprinted so as to obtain a non-planar circuit portion 111 having a predetermined height 111H and predetermined lateral dimensions and shape. One or more components 112 can be attached to the flexible printed circuit board 110 at any appropriate manufacturing stage, e.g. after the respective carrier material of the printed circuit board 110 has been imprinted by any appropriate technique, such as gluing, soldering, etc. The layers 122, 123 can be prepared so as to correspond in shape and thickness to the specific requirements of the pre-pack 100 and can also be provided in the form of webs which can be attached to each other and to the circuit board 110. This can be achieved in the condition that any of these material layers is still provided in the form of a web.

[0047] It will be appreciated that any coating or free film, such as the coatings 122A and 123A, can be applied at any appropriate manufacturing stage prior to attaching the material layers 122, 123 to the circuit board 110. The frame layer 124, including the respective films and coatings 124A, 124B, can be prepared separately and can also be attached to the circuit board 110, followed by the attachment of the frame structure 127 and the top and bottom layers possibly in combination with the respectively applied coatings 121S, 125S. Thereafter, appropriate process conditions can be established, e.g. by applying heat and pressure for a specific period of time, so as to laminate the various material layers and obtain the layer stack 120 having substantially planar surfaces 121S, 125S (see Figure 1 ). It will be appreciated that during the corresponding manufacturing process, the process conditions can be selected so as not to inappropriately affect, in particular, the components 112, which can require the application of a reduced lamination temperature of e.g. 120°C or less when the layer stack 120 is provided in the form of a PVC material. Similarly, the corresponding mechanical external pressure can be selected so as to avoid any mechanical damage of the components 112, wherein, as discussed above, in particular the frame layer 124 and the frame structure 127 can act so as to limit the resulting pressure acting on the components 112 to a desired non-critical amount.

[0048] Figure 3 A top view of a precursor sheet 150 which can be used to form a smart card or a respective pre-form thereof is schematically illustrated. In some illustrative embodiments, as shown in Figure 3 , the precursor sheet 150 is provided in the form of a web 152, wherein the various layers are provided in the form of webs which can be attached to each other and to the circuit board 110. In some illustrative embodiments, as shown in Figure 1 and Figure 2the features and characteristics discussed in the context of the pre-packaging 100A,..., 100N. Thus, the plurality of pre-packagings 100A,..., 100N, which are mechanically connected by the appropriate carrier material 151, form a well-defined lateral dimension 126, 127, which is significantly smaller compared to the lateral dimension of the respective smart card or pre-form thereof. Thus, due to the reduced lateral dimension 126, 127, i.e. the reduced shape parameter of the pre-packaging compared to the shape parameter of the final smart card, an increased precision of the pre-packaging can be achieved in general, which enables a highly precise positioning of the corresponding components 112 as well (see Figure 1 ), while the particular selection of the overall process conditions for forming the pre-packagings 100A,..., 100N also contributes to a good process yield and product reliability.

[0049] Based on the precursor sheet 150, the pre-packagings 100A,..., 100N can be further processed by being cut off from the carrier material 151 based on any appropriate technique for use in a smart card or pre-form thereof. Thus, the individual pre-packagings 100A,..., 100N can be obtained from the precursor sheet 150 for further processing.

[0050] Figure 4 A top view of a plurality of pre-forms 170A,..., 170K for smart cards is schematically illustrated. As shown, an array of pre-forms 170A,..., 170K is provided as a sheet of material 160, wherein the individual pre-forms 170A,..., 170K are mechanically interconnected by a respective carrier material 161. The pre-forms 170A,..., 170K can be processed in parallel based on appropriate process conditions to interconnect a plurality of material layers, which can have incorporated additional components, such as antennas for RFID devices, electronic modules, etc. Typically, the process conditions for forming the pre-forms 170A,..., 170K can be selected differently compared to the process conditions applied during the manufacturing process of the pre-packagings 100A,..., 100N in Figure 3 , as at least one of the components 112 (see Figure 1 ) can be more sensitive with respect to process temperature, pressure, etc. as discussed above.

[0051] Moreover, the pre-forms 170A,..., 170K can receive respective portions or openings 171 which correspond in lateral dimensions and shape to the pre-packagings 100A,..., 100N so as to enable proper insertion of the pre-packagings and attachment of the surrounding material of the pre-forms 170A,..., 170K. It will be appreciated that respective adhesive or filling material can be attached to the pre-packagings 100A,..., 100N and / or to the confining regions of the openings 171 so as to enable proper attachment of the pre-packagings. To this end, any suitable process conditions can be applied when inserting the individual pre-packagings into the respective openings 171 of the pre-forms 170A,..., 170K. After the pre-forms 170A,..., 170K have been completed by the carrier material 161 still interconnecting them, the sheet 160 can be supplied to a card manufacturer who can form a final card from the pre-forms 170A,..., 170K including the respective pre-packagings 100A,..., 100N, as discussed above.

[0052] Figure 5A A top view of a smart card 190 according to an illustrative embodiment is schematically illustrated. As already discussed above, the term smart card is to be understood as including any card-type device in which the lateral dimension is significantly larger than the respective height dimension or thickness of the smart card. For example, payment cards etc. generally defined by international standards, any type of RFID tag including electronic components etc. can be respective smart cards in the sense of the present application.

[0053] The smart card 190 has incorporated therein a pre-packaging 100 including respective components such as Figure 1 the illustrated component 112. For example, Figure 1 The component 112 can be a display which can be optically accessed through the card window 190W. Accordingly, respective symbols generated on the display 112 can be visible through the card window 190W, thereby conferring good functionality and / or security to the smart card 190. For example, in the field of credit cards or other payment cards, it is generally possible to provide a so-called card verification value (CVV) in order to enable good security when performing online transactions. In order to improve the overall security of online transactions, it has been proposed to periodically change the CVV and to display the value by means of a display upon user request.

[0054] It will be appreciated, however, that additionally or alternatively, the display can be provided to display any other symbols, characters, text and / or graphics so as to enable a good optical appearance and / or additional functionality.

[0055] Moreover, in Figure 5AIn the illustrated embodiment, the card portion 191 is formed in an adjacent manner to the portion of the pre-pack 100 that corresponds to, for example, has very similar characteristics in terms of thermal conductivity, etc., thereby ensuring consistent behavior during further processing of the smart card, for example, when printing symbols onto or into the portion 191 and possibly onto the portion associated with the pre-pack 100. Similarly, as discussed previously, the pre-pack 100 can be formed of any smart card compatible material at least at portions that can come into contact with the remaining card material of the smart card 190 in order to enable consistent behavior between the pre-pack 100 and the adjacent portion 191 during further processing and completion of the smart card 190.

[0056] Figure 5B A cross-sectional view of a smart card 190 according to an illustrative embodiment is schematically illustrated. As shown, the stack of card layers 195 (a portion of which can correspond to the pre-form 170A,..., 170K of the pre-pack 100,..., 100K discussed previously) can have the pre-pack 100 with characteristics and features as discussed previously embedded therein. Figure 4 Figure 1 Figure 2 The material layers of the pre-form 170A,..., 170K and in the context of the material layers discussed previously can have the pre-pack 100 with characteristics and features as discussed previously embedded therein. In particular, the window 125W (see Figure 1 ) can be provided in alignment with the card window 190W in order to allow access to particular components of the pre-pack 100 as discussed previously.

[0057] The smart card 190 can be formed from the pre-form 170A,..., 170K by attaching two or more additional card layers to the stack 195, while also providing additional features such as printed portions, embossed portions, coatings, etc., to comply with customer specific requirements. Thus, the smart card 190 can be provided with desired additional components such as displays, etc., with the pre-pack 100 ensuring high reliability of the final product since overall process robustness can be enhanced by forming the pre-pack 100 in a separate manner from the remaining portion of the smart card or its pre-form. Furthermore, specific process conditions can be selected for the pre-pack 100 if necessary, while the remaining smart card 190 or its pre-form can be formed based on different process conditions. Overall, separating the pre-pack 100 from the manufacture of the remaining pre-form enables the application of batch production techniques, for example, by providing the pre-pack as a web during processing of the pre-pack, and subsequently incorporating the individual pre-packs into the pre-form based on well-defined overall dimensions, thereby also contributing to enhancing the reliability of the overall manufacturing process.​​

Claims

1. A pre-pack for a smart card, comprising: a flexible printed circuit board comprising at least one non-planar circuit portion; a stack of material layers accommodating the flexible printed circuit board to provide a planar top surface and a bottom surface of the stack of material layers; and a frame sidewall structure laterally surrounding a central portion of the stack of material layers and laterally aligned with the top surface and the bottom surface to define a predetermined lateral dimension in an entire height direction of the pre-pack.

2. The pre-pack of claim 1, wherein the pre-pack has a height dimension orthogonal to the lateral dimension, and wherein the height dimension is less than 0.8 mm.

3. The pre-pack of claim 1 or 2, wherein at least one material forming a portion of at least one of the top surface and the bottom surface is a material for a smart card.

4. The pre-pack of claim 3, wherein the material forming a portion of at least one of the top surface and the bottom surface comprises at least one of PVC, polycarbonate, PET-G, ABS, and PET.

5. The pre-pack of claim 1 or 2, wherein the flexible printed circuit board comprises at least one of a display, a keypad, a sensor, a battery, an optical component, and an electronic component.

6. The pre-pack of claim 1 or 2, wherein the stack of layers comprises a frame layer surrounding at least a portion of the at least one non-planar circuit portion.

7. The pre-pack of claim 1 or 2, wherein the stack of material layers comprises a top layer forming at least a portion of the planar top surface and a bottom layer forming at least a portion of the planar bottom surface. the stack of material layers comprises a top layer forming at least a portion of the planar top surface and a bottom layer forming at least a portion of the planar bottom surface, and at least one of the top layer and the bottom layer comprises a window portion aligned with at least a portion of an opening of the frame layer.

8. The prepackage of claim 6, wherein, 9. A precursor sheet for forming smart cards, comprising: an array of the pre-packs of any one of claims 1 to 8; and a base material mechanically interconnecting the pre-packs of the array.

10. The precursor sheet of claim 9, wherein the precursor sheet is provided in a roll.

11. A smart card, comprising: a stack of card layers; and the pre-pack of any one of claims 1 to 8 embedded in the stack of card layers.

12. The smart card of claim 11, wherein the stack of card layers comprises a printed portion formed of a first material, and wherein a portion of the pre-pack positioned adjacent to the printed portion is formed of a second material having substantially the same thermal properties as the first material.

13. The smart card of claim 12, wherein the first material and the second material have substantially the same basic chemical composition. ​ 14. The smart card of any of claims 11 to 13, wherein the pre-pack has a window, and the smart card includes a card window that is at least partially aligned with the window.

15. The smart card of claim 14, wherein the card window is configured to enable at least one of mechanical, optical, visual, and electromagnetic interaction with the window of the pre-pack.

16. A method of forming a pre-pack for a smart card, the method comprising: providing an array of flexible printed circuit boards mechanically interconnected by a carrier material, each of the flexible printed circuit boards including at least one non-flat circuit portion; attaching the array of flexible printed circuit boards to a first layer of a smart card compatible material; laterally enclosing at least the non-flat circuit portion of each of the flexible printed circuit boards in the array by attaching a respective frame layer to the first layer for each of the non-flat circuit portions, each of the frame layers having an opening so as to accommodate at least the respective non-flat circuit portion and so as to at least partially level the non-flatness of the respective non-flat circuit portion; attaching a second layer formed of the smart card compatible material to the first layer to form a flat bottom surface; attaching a third layer formed of the smart card compatible material to the frame layers to form a flat top surface; and providing a frame sidewall structure laterally enclosing a central portion of the first, second, and third layers, and laterally aligned with the first and third layers, thereby defining a predetermined lateral dimension in an entire height direction of the pre-pack.

17. The method of claim 16, further comprising pre-preparing the frame layers according to lateral and height dimensions of the flexible printed circuit boards.

18. The method of claim 16 or 17, wherein the array of flexible printed circuit boards is provided in a form of a web, and wherein the first, second, and third layers formed of the smart card compatible material are provided in a form of a web.

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