Patent Description:
It is known at the state of the art to provide smart cards with light sources, in order to indicate an operating condition of the smart card, or to illuminate a portion of the smart card.

Document <CIT> describes for instance a dual interface smart card provided with a LED, which is placed in a core layer of the card. When a transaction is carried out, the dual-interface smart card is approached to a card reader. The card reader hence provides energy also to the LED light and generates a light flash, which indicates that the transaction is in progress. When the transaction is completed and the dual-interface smart card with the LED is removed from the card reader, no more power is supplied to the LED light, and accordingly the flashing effect of the LED light disappears.

On the other hand, document <CIT> discloses a card provided with illumination means for illuminating a graphic element formed on a card layer. The card body is provided with a recess in correspondence of the card layer and the recess is filled with a light collecting film, which comprises a transparent plastic material in which fluorescent dyes are embedded. A LED source may be added to the card body to power up the fluorescent dyes.

Document <CIT> discloses a smart card comprising an LED module disposed in an opening of the metal layer of the card. The LED module comprises a light guide and LEDs for projecting light horizontally into the light guide so as to illuminate an area. A logo or graphics are formed on or in the front layer covering the illuminated area so that the logo or graphics are back-lit by the LED module.

Document <CIT> discloses a light guide illumination system including a light guiding sheet and a plurality of discrete light extraction features forming a two-dimensional light extraction pattern and configured to extract light from light guide.

In the configurations known at the state of the art, the light emitted by the light sources, such as the diode and/or the fluorescent dyes, passes through the plastic material of the card layers and is accordingly scattered in all directions before reaching the eyes of the user. Therefore, the brightness of the emitted light is not uniform and the graphic elements may appear blurred.

The illumination module according to the present invention aims at overcoming one or more of the disadvantages of the state of the art.

According to an aspect of the present invention, an illumination module for illuminating a portion of a smart card and according to claim <NUM> is provided.

The advantage of this configuration is that the illumination module enables re-emitting the light of the lighting elements along the direction perpendicular to the substrate layer and enables obtaining a uniform brightness distribution over the area of the light guiding material.

In the present disclosure, it is to be understood that an illumination module indicates a modular unit which is configured for illuminating a portion of a smart card and which comprises one or more lighting elements and a light guiding material body.

In the present disclosure, it is to be understood that a light guiding material refers to any transparent optical material designed to transport and distribute light from a first material having a first refractive index and a second material having a second refractive index. The light guiding material transports light from one location to another by exploiting the principles of total internal reflection at the boundary between the two materials.

According to the present invention, the light guiding material may be made of PC, PVC, PMMA, PET, glass, acrylic glass, polyurethane or its blends, LDPE, polysulfone, or transparent epoxy resins.

Preferably, the light guiding material does not comprise fluorescence molecules nor any other doping particles. The fact that the light guiding material of the invention does not comprise fluorescence molecules is advantageous because the light emitted by the lighting elements is entirely transmitted to the light guiding material and to the other layers, without any other energy conversion process. Moreover, in this way, the illumination module stops illuminating the other card layers immediately after switching off the lighting elements, without dwell times which would occur with fluorescence molecules.

The light guiding material has a refractive index higher than the refractive index of the surrounding layers, such as the other layers of the smart card. In this way, once the light has entered the light guiding material, it is reflected between the top and bottom surfaces due to total internal reflection and keeps travelling until it hits an out-coupling structure, such as the protrusions formed thereon. In fact, the protrusions of the pattern layer have a different refractive index compared to the other materials surrounding the light guiding material. Therefore, they modify the interface of the light guiding material with the other card layers so that, in the areas occupied by the protrusions, the rays of the emitted light, depending on their incident angle, are not totally internally reflected within the light guiding material, but they are partially extracted and emitted outside the light guiding material. In this sense, the protrusions enable extraction of the light emitted by the lighting elements.

According to a preferred configuration, the height of the light emitting area of the LED is designed in such a way as to correspond with the thickness of the layer of light guiding material. According to another preferred configuration, the height of the light emitting area of the LED is shorter than the thickness of the light guiding material to ensure that most of the light emitted from the LED surface is transmitted into the light guiding material. Preferably, the light guiding material may have a thickness comprised between <NUM> micrometers and <NUM> micrometers.

According to the invention, the pattern layer is designed so as to comprise a series of protrusions that are distributed so as to make the brightness of the emitted light uniform. The design and structure of the protrusions in the pattern layer are adapted to the positions of the lighting elements. For instance, the linear or superficial density of the protrusions on the pattern layer is adapted to the positions of the lighting elements. For instance, the dimensions (e.g. width and height) of the protrusions on the pattern layer is adapted to the positions of the lighting elements.

Preferably, the protrusions are formed on the upper side of the light guiding material, that is the side of the light guiding material opposite to the substrate layer.

According to a preferred configuration, the lighting elements may be LEDs. The radiation pattern of top- or side-emitting LEDs is ideal for highest in-coupling efficiencies. According to other preferred configurations, the lighting elements may be Organic Light-Emitting diodes (OLEDs), printable Nano LED pastes, electroluminescent pastes, and/or silicon based LASERs.

According to an embodiment of the present invention, an illumination module is provided, wherein the protrusions are printed dots.

The printed dots may be white dots. The printed dots may be formed by means of any printing technique, such as screen printing, offset printing, ink jet printing or similar.

The advantages of forming the dots of the pattern layer by means of printing technology are that printing is a simple and efficient process, and that it enables adapting the printed pattern to any configuration and positions of the lighting elements with respect to the light guiding body. Moreover, printing enables realizing different configurations based on the type of light guiding material employed.

According to another embodiment of the present invention, an illumination module is provided, wherein the protrusions are bubbles formed from the light guiding material.

The bubbles may be formed in the light guiding material by means of laser processing. For instance, the light guiding material can be irradiated with a laser and this process may induce the formation of bubbles inside the material, which act as lenses to deviate the emitted light and extract it from the light guiding material.

The advantage of the laser processing technology is that it can be adapted to the specific configuration of the light guiding material and to the configuration and/or positions of the lighting elements. Moreover, the laser processing technology is very precise and it enables forming the bubbles only on the portion of the light guiding material corresponding to the area to be illuminated, thus avoiding emission of light from areas surrounding the portion to be illuminated.

According to another embodiment of the present invention, an illumination module is provided, wherein the protrusions are due to the formation of blind holes in the light guiding material as a consequence of laser processing.

For example, laser processing can be used to create blind holes in the light guiding material by ablation from its top surface.

According to another embodiment of the present invention, an illumination module is provided, wherein the linear density of the protrusions increases by increasing their distance from the one or more lighting elements.

The advantage of this configuration is that the position and design of the protrusion ensures a uniform distribution of the brightness of the light emitted by the lighting elements and refracted by the light guiding material. For instance, when a user observes the illumination module, they may see a more uniform brightness distribution of the emitted light.

According to another embodiment of the present invention, an illumination module is provided, wherein a surface of each of the one or more lighting elements is positioned in contact with the edges of the light guiding material, so as to have no gap between the lighting element and the light guiding material and to facilitate transmission of the emitted light.

The advantage of this configuration is that the light beam is transmitted directly from the lighting element into the light guiding material. A gap between the two elements would imply a change of refractive index between the two materials and would cause a partial energy loss.

According to an alternative embodiment of the present invention, an illumination module is provided, wherein a gap is formed between the lighting element and the light guiding material and the gap is filled with a gap filling material having a refractive index suitable for enabling transmission of light within the gap.

The advantage of filling the gap with a gap filling material is that the light emitted by the lighting elements is not reflected by the gap or by the sidewalls of the light guiding material and is hence transmitted in the light guiding material.

The refractive index of the gap filling material is selected in such a way as to optimize transmission of the light emitted by the lighting element into the gap material and then into the light guide material. Preferably, the gap filling material may be made of PC, PVC, PMMA, PET, glass, acrylic glass, polyurethane or its blends, LDPE, polysulfone, or transparent epoxy resins. Preferably, the gap filling material is made of the same material as the light guiding material.

Preferably, the light guiding material may have one or more recesses formed at the edges in order to accommodate the lighting elements. Preferably, the lighting elements are positioned at the same level of the layer of the light guiding material.

According to another embodiment of the present invention, an illumination module is provided, wherein the width of the pattern layer is shorter than the width of the light guiding material and/or the length of the pattern layer is shorter than the length of the light guiding material.

The advantage of this configuration is that the size of the pattern layer can be adapted to the size of the corresponding portion of the smartcard that needs to be lighted up on card level. In fact, only in this area to be illuminated, the light should be extracted out of the light guiding element, whereas, in the other areas, the emitted light is preferably reflected within the light guiding material.

According to another embodiment of the present invention, an illumination module is provided, wherein each protrusion has a circular shape with a diameter comprised within the range between <NUM> and <NUM>, preferably comprised within the range between <NUM> and <NUM>, even more preferably of <NUM>.

These dimensions ensure that the protrusions are small enough so as to ensure an even distribution and a uniform brightness of the light emitted by the light guiding body.

Preferably, the protrusions have a height comprised within the range between <NUM> and <NUM>.

According to the present invention, the illumination module further comprises a reflective layer configured to reflect the light emitted by the lighting elements outside the light guiding material and to re-direct it inside the light guiding material.

The advantage of this configuration is that it reduces energy losses.

According to a preferred configuration, the reflective layer is applied to the side of the substrate layer opposite to the light guiding material.

The advantage of this configuration is that it avoids back scattering of the light emitted by the lighting elements from the back of the illumination module, that is from the portion of the illumination module, opposite to the light guiding material. Preferably, the reflective layer may be bonded to the light guiding material by using an adhesive having a lower refractive index compared to the refractive index of the light guiding material. According to alternative embodiments, the reflective layer may be bonded directly to the light guiding material, without using any adhesive, by using for instance metal deposition (PVD) or direct lamination onto the light guiding material.

According to another embodiment of the present invention, an illumination module is provided wherein at least one reflective portion is applied in correspondence with the lighting element.

The advantage of this configuration is that the light which is emitted by the lighting elements directly towards the user and which does not pass through the lighting material is blocked. In this way, when the user looks at the illumination module, they do not see bright spots in correspondence with the lighting elements, but they see a uniform brightness of emitted light in correspondence with the illuminated portion of the substrate layer.

According to an embodiment of the present invention, an illumination module is provided wherein the reflective layer and/or the reflective portions comprise a metal layer or a metalized layer.

The advantage of this configuration is that the metal layer or the metalized layer enable forming a reflective layer in a simple and efficient way. For instance, the metal layer may be formed of aluminum, magnesium, copper, silver, or gold, or they may be formed of other reflective materials.

According to another embodiment of the present invention, an illumination module is provided, wherein the substrate layer is a Printed Circuit Board (PCB).

The advantage of this configuration is that the substrate layer can accommodate the optical and electronic components, such as diodes and/or capacitors, of the illumination module. Moreover, the illumination module can be manufactured and tested independently from the manufacturing process of the pre-laminated structure or of the smart card. In fact, the positions of the protrusions of the pattern layer with respect to the other electronic components can be controlled in a very precise way at an early stage of manufacturing of the final smart card. This also ensures a quality inspection about the brightness distribution before all elements are assembled into the pre-laminated structure and into the smart card.

According to preferred configurations, the PCB can comprise a metal layer underneath the light guiding element. This metal layer can act as a reflection layer or as an absorption layer.

According to an alternative embodiment of the present invention, an illumination module is provided, which comprises a PCB having a cutout portion, wherein the light guiding body is placed within the cutout portion.

The advantage of this configuration is that the illumination module can have a reduced thickness because the light guide body is inserted into the cutout portion of the PCB, not on top of the PCB.

According to another embodiment of the present invention, an illumination module is provided, wherein the illumination module comprises a plurality of lighting elements, for example a plurality of LEDs, and the plurality of lighting elements is formed on a single PCB.

The advantage of this configuration is that the production costs are optimized. Moreover, a single PCB comprising all the LEDs ensures a more precise positioning of same with respect to a configuration wherein one or more PCBs are used to accommodate corresponding LEDs, because it reduces the errors due to positioning of the LEDs on the PCBs and of placing the PCBs one next to the other.

According to a preferred configuration, the PCB comprising the LEDs may be formed so as to surround the light guiding material.

According to a preferred configuration, the light guiding material may have the shape of a rectangle and may be surrounded by the PCB, which may also have a rectangular shape.

According to other preferred configurations, the light guiding material may have any desired shape, such as a square, oval, triangle, or rounded shape. The PCB may be accordingly formed so as to surround or be placed below the light guiding material with the same shape as the light guiding material.

According to other preferred configurations, the PCB may have the shape of a regular polymer, such as a hexagonal or an octagonal shape, wherein at each or at every second side of the polymer of the PCB, an LED is positioned.

According to another embodiment of the present invention, an illumination module is provided wherein the light guiding body comprises an orientation element for ensuring correct positioning of the light guiding body with respect to the one or more lighting elements.

The advantage of this configuration is that ensures correct positioning of the light guiding body in the illumination module. In fact, it is clear that the light guiding material and also the pattern layer have a preferred orientation with respect to the lighting elements in the illumination module in order to ensure uniform brightness and refraction of light. Therefore, it is important that during the manufacturing processes, the operator places the light guiding body in the illumination module with the correct orientation.

According to another embodiment of the present invention, an illumination module is provided which further comprises an energy harvesting antenna for providing energy to the one or more lighting elements.

The advantage of this configuration is that the illumination module does not need an additional battery for providing energy to the lighting elements and it is therefore more economical.

According to another embodiment of the present invention, an illumination module is provided, wherein the one or more lighting elements are LEDs and the illumination module further comprises a rectifying system for rectifying the signal emitted by the energy harvesting antenna before transmitting it to the LED.

The advantage of this configuration is that the alternating signal, which is emitted by the energy harvesting antenna after exposure to an electromagnetic field generated by a reader, is converted into a rectified signal before being transmitted to the LEDs.

Preferably, the rectifying system of the present invention may be the electronic carrier <NUM> disclosed in the international patent application <CIT> from the same applicant.

According to another aspect of the present invention, a pre-laminated structure for a smart card is provided, which comprises a pre-lam body comprising a cut out portion and an illumination module as the ones described above, wherein the illumination module is positioned in the cut out portion.

The advantage of this configuration is that a pre-laminated structure is provided wherein a portion of the substrate layer may be illuminated by the lighting elements and may be visible from the pre-lam body.

In the present disclosure, it is to be understood that the pre-laminated structure (also referred to as "pre-lam") for a smart card refers to an intermediate structure, which is formed in the manufacturing process of the smart card before lamination to the final covering layers of the smart card. The pre-laminated structure comprises a plurality of card layers stuck together so as to form a multi-layered structure and it further comprises the electronic components of the smart card, such as the antennas and the integrated circuit. The covering layers of the smart card comprising other graphic information are then added at a later stage of the manufacturing process of the smart card.

According to another embodiment of the present invention, a pre-laminated structure is provided, which further comprises a graphic layer comprising a graphic element, wherein the graphic layer is attached to the pre-lam body in correspondence with the illumination module, so that the illumination module illuminates the graphic element.

The advantage of this configuration is that the light emitted from the illumination module can be used to illuminate the portion of the graphic layer comprising the graphic element. The graphic element is preferably a logo of the card.

Examples of the techniques used for forming the graphic element are the following: off-set printing, screen printing, ink-jet printing, transfer printing, LASER processing (that is modifying laser sensitive molecules in the foil layer.

The pre-laminated structure of the present invention may advantageously contain a transparent or translucent window formed in an opaque layer positioned above the illumination module. The window may be advantageously formed in correspondence with the illumination module so as to expose the portion of the substrate layer which is illuminated by the lighting elements. For instance, the window may be formed in correspondence with the graphic element of the substrate layer.

According to another embodiment of the present invention, a pre-laminated structure is provided, wherein one or more light reflective portions are formed on the side walls of the cut out portion in correspondence with the one or more lighting elements.

The advantage of this configuration is that the light reflective portions formed at the lateral surfaces of the lighting elements prevent lateral back-scattering of the light emitted by the lighting elements and reduce energy loss. Hence, the light reflective portions contributes to forming a uniform and clear image of the portion of the graphic layer that is illuminated by the lighting elements.

According to another aspect of the present invention, a pre-laminated structure is provided, which further comprises a reflective layer configured to reflect the light emitted by the lighting elements outside the light guiding material and to re-direct it inside the light guiding material, or a blocking layer configured to absorb the light emitted by the lighting elements outside the light guiding material.

The advantage of this configuration is that it enables creating an image of the graphic element without blurred portions or portions with excessive brightness.

According to another aspect of the present invention, a smart card is provided, which comprises a pre-laminated structure as the ones described above; at least one opaque, covering layer applied to the pre-laminated structure; and at least one clear, covering layer applied to the pre-laminated structure.

It is to be understood that a clear layer may be transparent or translucent.

According to an embodiment of the present invention, the graphic layer comprising the graphic element to be illuminated may be formed on a layer of the smart card, not on a layer of the pre-laminated structure.

The smart card according to the present invention is advantageous because it enables illuminating a portion of the graphic layer formed in the pre-laminated structure or in the smart card by means of the illumination module, thanks to the lighting elements formed thereon. For instance, it may be useful to illuminate a portion of the graphic layer in order to see a graphic element, such as a logo of the smart card, formed thereon. For instance, it may be useful to illuminate a portion of the graphic layer in order to detect a working condition of the smart card, such as a condition wherein a transaction is carried out. In both examples, the smart card of the present invention enables re-emitting the light with a uniform brightness. For instance, the smart card according to the present invention ensures seeing a neat and clear image of the graphic element.

Preferably, the smart card comprises both an energy harvesting antenna for providing energy to the light emitting sources and a payment antenna for enabling transactions with an external reader.

Preferably, the smart card comprises both an energy harvesting antenna for providing energy to the light emitting sources and another transponder antenna connected to a RFID chip enabling contactless communication with an external reader, for example for access control applications.

Preferably, the RFID chip may be mounted on the same PCB as the one accommodating the electronic and optical components of the illumination module.

According to a preferred configuration, a user exposes the smart card to an external reader generating an electromagnetic field. A signal is accordingly generated in the energy-harvesting antenna and is used to power up the LEDs of the illumination module. The LEDs emit light, which is refracted by the light guiding material and the pattern layer and is then re-emitted in the direction of the user. Thanks to the presence of the pattern layer, the brightness of the re-emitted light is made uniform. The re-emitted light finally passes through the other layers of the smart card and reaches the user. A window is advantageously formed in the layers of the smart card in correspondence with the illuminated portion of the graphic layer, so as to make it visible also in the final smart card.

In the following description, reference is made to the following figures:.

The present description is presented for purposes of illustration but is not intended to be exhaustive or limited to the disclosed embodiments. The scope of protection of the present disclosure is defined in the appended set of claims. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the disclosure. The embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated. Finally, those fields considered known to the skilled person will not be described to avoid covering in a useless way the described invention.

In the present invention, it is to be understood that the terms "top", "bottom", "right", "left", "side", and variations thereof refer to the orientation of the figures but they do not intend to limit the invention.

<FIG> schematically illustrates a top view of a smart card <NUM> according to an embodiment of the present invention. The smart card <NUM> comprises a pre-lam body <NUM>, in which a cutout portion is formed. In the cutout portion, an illumination module <NUM> is placed.

The illumination module <NUM> comprises a substrate layer <NUM> on which a light guiding body <NUM> is applied. The light guiding body <NUM> comprises a layer of light guiding material <NUM>, on which a pattern layer <NUM> is formed. An adhesive layer (not shown) may be used to bond the light guiding body <NUM> to the substrate layer <NUM> and to the other layers of the card. Alternatively, the light guiding body <NUM> may be directly bond to the substrate layer <NUM> and to the other layers of the card. In the configuration shown in <FIG>, four lighting elements <NUM> are formed along the perimeter of the light guiding body <NUM>. The lighting elements <NUM> may be for instance LEDs.

Even if in the configuration of <FIG>, four LEDs are illustrated, it appears that any number of LEDs may be formed on the illumination module <NUM>, for instance one, two, three, or more.

The light emitted by the lighting elements <NUM> is parallel to the substrate layer <NUM> and travels through the light guiding material <NUM>. The lighting elements <NUM> are advantageously positioned at the same level as the light guiding material <NUM>. For example, the light guiding body <NUM> may have one or more recesses at the edges to accommodate corresponding lighting elements <NUM>.

The light guiding material <NUM> may be made of PC, PVC, PMMA, PET, glass, acrylic glass, polyurethane or its blends, LDPE, polysulfone, or transparent epoxy resin.

The light guiding body <NUM> is configured in such a way as to refract the light emitted by the lighting elements <NUM> and to deviate it along a direction perpendicular to the substrate layer <NUM>. The light guiding material <NUM> has a higher refractive index compared to the surrounding materials, such as the adhesive, and/or the substrate layer <NUM>, and/or the other layers of the smart card <NUM>.

Preferably, the light emitted by the lighting elements <NUM> is deviated along the direction perpendicular to the substrate layer <NUM> which is directed towards the eyes of the user of the smart card <NUM>.

As can be seen in <FIG>, the illumination module <NUM> further comprises a harvesting antenna <NUM> which is used to provide energy to the lighting elements <NUM> when the smart card <NUM> is exposed to an electromagnetic field. Moreover, the illumination module <NUM> of <FIG> comprises a rectifying system <NUM>, which is used to rectify the alternating signal emitted by the harvesting antenna <NUM> before transmitting it to the lighting elements <NUM>.

The position and configuration of the energy-harvesting antenna <NUM> of the present invention may be similar to the position and configuration of the energy-harvesting antennas <NUM>, disclosed in the international patent application <CIT>.

According to a preferred configuration, the lighting elements <NUM> may be LEDs and the rectifying system <NUM> may be used to rectify the alternating signal emitted by the harvesting antenna <NUM> before transmitting it to the LEDs. For example, the rectifying system <NUM> may be a four-diode bridge. Alternatively, the rectifying system <NUM> may be the electronic carrier <NUM> disclosed in the international patent application <CIT> from the same applicant.

In the configuration shown in <FIG>, the rectifying system <NUM>, the lighting elements <NUM> and any other electronic components such as capacitors and/or diodes are formed on a single PCB <NUM>, which is connected to the harvesting antenna <NUM>. The PCB <NUM> surrounds the light guiding body <NUM> and is placed on the substrate layer <NUM>. The PCB <NUM> may have any shape suitable for exposing a portion of the light guiding body <NUM>, so as to emit light in a direction perpendicular to the substrate layer <NUM>. In the configuration illustrated in <FIG>, the PCB <NUM> has a rectangular shape and surrounds the light guiding body <NUM>, which also has a rectangular shape, so that a portion of the light guiding body <NUM> and of the substrate layer <NUM> are visible at the center of the PCB <NUM>.

According to alternative configurations (not shown), the PCB <NUM> and the light guiding body <NUM> may have any other shape, such as a squared, an oval, a triangular, or a round shape, or even a polygonal shape, for instance the shape of a regular polygon.

According to a preferred configuration (not shown), the PCB <NUM> may have a symmetric multi-corner shape (e.g., hexagonal, octagonal, or the like), wherein at each or at every second side a LED <NUM> is positioned.

In order to improve the visibility of the graphic element of the smart card, a pattern layer <NUM> is applied on the light guiding material <NUM>. The pattern layer <NUM> comprises a series of protrusions <NUM> distributed so as to make uniform the brightness of the light that is emitted by the lighting elements <NUM> and deviated by the light guiding body <NUM>.

According to a preferred embodiment of the invention, the protrusions <NUM> may be printed dots. For instance, the printed dots may be printed by means of any suitable technique such as screen printing, offset printing, inkjet printing or similar. The printed dots may be made of a different material with respect to the material of the light guiding element <NUM>.

According to another preferred embodiment of the present invention, the series of protrusion may comprise a series of bubbles formed from the light guiding material <NUM> by illuminating the light guiding material <NUM> with a suitable laser. During the laser treatment, bubbles are created in the light guiding material <NUM> due to increased temperature. Accordingly, the bubbles are made of the same material as the light guiding element <NUM>. The bubbles act as lenses on the emitted light and make the brightness more uniform and facilitate seeing the graphic element <NUM> on the substrate layer <NUM>.

<FIG> schematically illustrates a three dimensional view of the light guiding body <NUM> according to an embodiment of the present invention. In <FIG>, it can be seen that the area of the pattern layer <NUM> is smaller than the area of the light guiding material <NUM>. In particular, in the configuration of <FIG>, the length L2 of the pattern layer <NUM> is shorter than the length L1 of the light guiding material <NUM> and the width W2 of the pattern layer <NUM> is equal to the width W1 of the light guiding material <NUM>.

According to alternative configurations (not shown), the width W2 of the pattern layer <NUM> may be shorter than the width W1 of the light guiding material <NUM> and the length L2 of the pattern layer <NUM> may be equal to the length L1 of the light guiding material <NUM>. According to other configurations (not shown), both the width W2 and the length L2 of the pattern layer <NUM> may be shorter than the width W1 and the length L1 of the light guiding material <NUM>.

In the configuration of <FIG>, it is possible to see that the light emitted by the lighting elements <NUM> passes through the light guiding material <NUM> in a direction parallel to the substrate layer <NUM>, i.e. parallel to the plane XY with reference to the Cartesian reference system of <FIG>. The light is then deviated and refracted along the direction perpendicular to the substrate layer <NUM>, i.e. along the Z direction with reference to the Cartesian reference system of <FIG>. Preferably, the Z direction is directed towards the eyes of the user who is holding the smart card <NUM>.

The pattern design of the pattern layer <NUM> is made in such a way as to equally distribute the brightness of the emitted light over the main part of the area of the light guiding material <NUM>. This is achieved by variating the density of the protrusions in the pattern layer <NUM>. As it can be seen in <FIG>, the linear density of the protrusions <NUM> increases by increasing their distance from the lighting elements <NUM>.

A detail of the distribution of the protrusions on the pattern layer <NUM> is shown in <FIG>, which has been obtained by means of computer simulations with the simulation software LightTools.

The pattern layer <NUM> of <FIG> can be ideally divided into four symmetric regions A, B, C and D. The region A is placed in correspondence of the lighting source 110A. The region B is placed in correspondence of the lighting source 110B. The region C is placed in correspondence of the lighting source 110C. The region D is placed in correspondence of the lighting source 110D. In each region A, B, C or D the linear density of protrusions <NUM> increases by increasing the distance from the corresponding lighting element <NUM>. In this way, the linear density of protrusions is lower in close proximity with the lighting element <NUM> and is higher at the interface between adjacent regions, such as at the center O of the pattern layer <NUM> and in correspondence of delimiting lines <NUM>, <NUM>, <NUM> and <NUM> illustrated in <FIG>. Moreover, the linear density of protrusions increases also in correspondence of the middle points <NUM> and <NUM> of the sides W2 and of the middle points <NUM> and <NUM> of the sides L2 shown in <FIG>.

<FIG> schematically illustrates a cross sectional view of the illumination module <NUM> according to an embodiment of the present invention. In the configuration of <FIG>, it is possible to see that the light guiding material <NUM> is applied to the substrate layer <NUM> and that the protrusions or dots <NUM> of the pattern layer of <NUM> are formed thereon. With reference to the orientation of <FIG>, the protrusions <NUM> are made on the upper side of the light guiding material <NUM>. In the schematic configuration of <FIG>, the protrusions <NUM> are illustrated as being equally spaced between each other. However, their reciprocal distance depends on the distance from the lighting sources <NUM>, as explained above.

<FIG> schematically illustrates a three dimensional view of the illumination module <NUM>, wherein the protrusions <NUM> or dots of the pattern layer <NUM> are clearly visible. Preferably, the protrusion may be wide printed dots having a circular shape with a diameter comprised in the range between <NUM> and <NUM>, preferably between <NUM> and <NUM>, even more preferably of <NUM>.

<FIG> schematically illustrates a cross sectional view of an illumination model <NUM> according to a preferred embodiment of the present invention. In <FIG>, it is possible to see that a reflective layer <NUM> is placed between the substrate layer <NUM> and the light guiding material <NUM>. The reflective layer <NUM> may be a foil of a metal material or of a metalized material. The metal may be aluminum, magnesium, or copper. The reflective layer <NUM> can be used to block part of the light emitted by the lighting elements <NUM> and to prevent back-scattering. In other words, the reflective layer <NUM> may be used to prevent that part of the emitted light is scattered from the side of the smart card <NUM> which is not directed towards the user (i.e. the side opposite to the pattern layer <NUM>). In this way, the light emitted by the light guiding body <NUM> has even a more uniform brightness. In fact, the light emitted by the backside of the light guiding body <NUM> would create a blurred image of the graphic element.

The illumination module <NUM> according to the invention may be used to illuminate a portion of a graphic layer of a smart card <NUM>, for instance to enable seeing a logo of a smart card or to indicate a working condition of the smart card. As it can be visible in <FIG> below, the graphic layer may be formed in the pre-laminated structure, or in the smart card.

During manufacturing of the smart card, the illumination module <NUM> is inserted into a predefined cutout portion of the pre-laminated structure <NUM> of the smart card. The final covering layers of the smart card <NUM> are then added to the pre-laminated structure <NUM> to cover it.

<FIG> schematically illustrates a three dimensional view of a portion of a pre-laminated structure <NUM> for a smart card <NUM> according to an embodiment of the present invention. In <FIG>, it can be clearly visible that the illumination module <NUM> is inserted into a cutout portion of the pre-lam body <NUM>. Along the side walls of the cutout portion, one or more reflective portions 140A, 140B and 140C may be formed. Preferably, the reflective portions 140A, 140B and 140C are placed in correspondence with the lighting elements <NUM> in order to prevent light from being scattered by the sides of the cutout portion and to improve the quality of the image of the graphic element of the smart card. Thanks to the reflection portions 140A, 140B, 140C and 140D, the energy loss of the emitted light is reduced and more emitted light finally reaches and illuminates the graphic element. Therefore, the reflective portions help to increase the brightness of the light that is illuminating the area of the graphic element.

The reflective portions 140A, 140B and 140C may be formed of a thin metal or metalized layer, such as a thin layer comprising aluminum, magnesium, copper, silver, or gold, or they may be formed of other reflective materials.

In view of the above disclosure, it is clear that the illumination module <NUM> has a preferred orientation and that the light guiding body comprising the light guiding material <NUM> and the pattern layer <NUM> should be placed on the illumination module <NUM> is such a way as to have a preferred orientation with respect to the lighting elements <NUM>. For example, the linear density of the protrusions <NUM> of the pattern layer <NUM> should be higher at increasing distance from the lighting elements <NUM>. Moreover, the light guiding material <NUM> should be placed in such a way as to be able to refract light along a direction perpendicular to the substrate layer <NUM>.

In order to ensure correct positioning of the light guiding body <NUM> with respect to the lighting elements <NUM>, the light guiding body <NUM> may be provided with the orientation element <NUM>. For instance, the orientation element <NUM> may be a protrusion or nose, which indicates a preferred orientation of the light guiding body <NUM> for its positioning in the illumination module <NUM>. In this way, during manufacturing, the operator may position the light guiding body <NUM> so that the light guiding material <NUM> and the pattern layer <NUM> have a preferred orientation with respect to the lighting elements <NUM>. The configuration of the illumination module <NUM> with the light guiding body <NUM> provided with an orientation element <NUM> is schematically illustrated in <FIG>.

As it is schematically shown in <FIG>, the cutout portion of the pre-laminated structure <NUM> is shaped so as to match the configuration of the orientation element <NUM>.

<FIG> schematically represents a cross sectional view of smart card <NUM> according to an embodiment of the present invention.

In <FIG>, it is possible to see that the illumination module <NUM> is placed in a cutout portion formed in the pre-lam body <NUM> of the pre-laminated structure <NUM> for the smart card <NUM>. The illumination module <NUM> comprises the lighting elements <NUM> (only two lighting elements are visible in the cross section of <FIG>). The light guiding body <NUM> comprising the light guiding material <NUM> and the pattern layer <NUM> is positioned between the lighting elements <NUM>. An antenna <NUM> is formed around the light guiding body <NUM> in order to provide energy to the lighting elements <NUM>.

In the configuration shown in <FIG>, the PCB <NUM> surrounds the light guiding body <NUM> and is placed on the substrate layer <NUM>, as described with reference to <FIG>. The lighting elements <NUM> and the connection pads of the harvesting antenna <NUM> are formed on the single PCB <NUM>.

In the configuration shown in <FIG>, the pre-laminated structure <NUM> further comprises a graphic layer <NUM> which is attached to the top of the illumination module <NUM>. The graphic layer <NUM> comprises a graphic element <NUM> which receives the light emitted by the illumination module. In this way, the graphic element <NUM> may be visible by the user. Preferably, the pattern layer <NUM> is formed only in correspondence of the area of the graphic layer <NUM> comprising the graphic element <NUM>, in order to extract the light from the corresponding portion of the light guiding material <NUM> and to illuminate only the area of the graphic element <NUM>. In this way, the image of the graphic element <NUM> is clear and bright.

In the configuration of <FIG>, also a reflective layer <NUM> is formed on the backside of the illumination module <NUM> in order to prevent back scattering of the light emitted by the lighting elements <NUM>, in the direction opposite to the one of the user (the bottom of <FIG>). The reflective layer <NUM> may be directly or indirectly attached to the light guiding body <NUM>. For instance, the reflective layer <NUM> may be indirectly attached to the light guiding body <NUM> by means of an adhesive layer (not shown).

Moreover, in the configuration of <FIG>, reflective portions <NUM> are formed in correspondence with the lighting elements <NUM>, in the direction opposite to the reflective layer <NUM>. Furthermore, the pre-laminated structure <NUM> of <FIG> comprises an additional reflective layer <NUM> for reflecting the light emitted by the lighting elements <NUM> outside the light guiding body <NUM> and redirected it into same. In this way, when the user observes the smart card <NUM> from the top, they can see the graphic element <NUM> without seeing spots of excessive brightness in correspondence with the lighting elements <NUM>. In fact, the direct light emitted by the lighting elements <NUM> in other directions is blocked by the reflective portions <NUM> and by the reflective layer <NUM>. The reflective portions and layers may be made of any metal or metalized material.

An integrated circuit (not shown) may be further formed in the pre-lam body <NUM>. The integrated circuit may be formed directly into the illumination module <NUM>, or in another layer of the pre-laminated structure <NUM>. The pre-lam body <NUM> comprising the illumination module <NUM> and the integrated circuit forms the pre-laminated structure <NUM> of the smart card <NUM>.

The pre-laminated structure <NUM> of the smart card <NUM> is placed between covering layers. Preferably, top and bottom opaque covering layers <NUM> are attached to the pre-laminated structure <NUM>. Preferably, top and bottom clear covering layers <NUM> are attached to the corresponding opaque covering layers <NUM> of the smart card <NUM>. Preferably, the opaque covering layers <NUM> comprise white PVC sheets. Preferably, the clear covering layers <NUM> comprise clear PVC sheets.

As schematically shown in <FIG>, the smart card <NUM> of the present invention may advantageously comprise a transparent or translucent window <NUM>, which is formed in the white or opaque covering layer <NUM>. The window <NUM> is advantageously aligned with the light guiding body <NUM>, so that the light emitted by the illumination module <NUM> illuminates the graphic element <NUM> and reaches the user by passing through the transparent window <NUM>.

<FIG> schematically represents a cross sectional view of smart card <NUM> according to an alternative embodiment of the present invention.

The smart card <NUM> of <FIG> comprises the same elements as the smart card <NUM> of <FIG>, but it differs from it in that the pre-laminated structure <NUM> does not comprise any graphic layer.

The graphic element <NUM> of the smart card <NUM> of <FIG> is formed in the graphic layer <NUM> which is attached to the pre-laminated structure <NUM> at a late stage of manufacturing, during lamination of the final layers of the smart card. Preferably, the graphic element <NUM> is a printed element.

When the lighting elements <NUM> are activated, the graphic element <NUM> is visible by the user. Preferably, the pattern layer <NUM> is formed only in correspondence with the area of the graphic layer <NUM> comprising the graphic element <NUM>, in order to extract the light from the corresponding portion of the light guiding material <NUM> and to illuminate only the area of the graphic element <NUM>. In this way, the image of the graphic element <NUM> is clear and bright.

Moreover, the smart card <NUM> of <FIG> differs from the smart card of <FIG> in that the reflective layer <NUM> is replaced by a blocking layer <NUM>, which stops and absorbs the light emitted by the lighting elements <NUM> in the direction opposite to the user (i.e. the bottom of <FIG>). In this way, backscattering of the emitted light is reduced and the image of the graphic element <NUM> is clearer.

The smart card <NUM> of <FIG> comprises the same elements as the smart card <NUM> of <FIG>, but it differs from it in the configuration of the PCB. In fact, in the smart card <NUM> of <FIG>, the PCB forms the substrate layer <NUM> of the illumination module <NUM>. In other words, the PCB <NUM> does not surround the illumination module <NUM>, but it forms the substrate layer on which the optical components, such as the light guiding body <NUM>, and the electrical components (such as antenna <NUM> and rectifying element <NUM> and other diodes and/or capacitors) are formed.

In the configuration of <FIG>, the reflective layer <NUM> is attached to the bottom of the PCB layer <NUM>.

The smart card <NUM> of <FIG> comprises the same elements as the smart card <NUM> of <FIG>, but it differs from it in the configuration of the PCB. In fact, in the smart card <NUM> of <FIG>, the PCB forms the substrate layer <NUM> of the illumination module. In other words, the PCB <NUM> does not surround the illumination module <NUM>, but it forms the substrate layer on which the optical components, such as the light guiding body <NUM>, and the electrical components (such as antenna <NUM> and rectifying element <NUM> and other diodes and/or capacitors) are formed.

<FIG> schematically represents a cross sectional view of smart card <NUM>. As illustrated in the smart card <NUM> of <FIG>, the pre-laminated structure <NUM> comprises the reflective layer <NUM> for reflecting the light emitted by the lighting elements <NUM> in the direction opposite to the user (bottom of <FIG>) and reducing energy losses.

Claim 1:
An illumination module (<NUM>) for illuminating a portion of a smart card, said illumination module (<NUM>) comprising:
- A substrate layer (<NUM>);
- One or more lighting elements (<NUM>) positioned on said substrate layer (<NUM>) and configured to emit light parallel to said substrate layer (<NUM>), for instance one or more LEDs; and
- A light guiding body (<NUM>) applied to said substrate layer (<NUM>) and comprising a light guiding material (<NUM>);
characterized in that:
said illumination module (<NUM>) further comprises a reflective layer (<NUM>) configured to reflect the light emitted by said lighting elements (<NUM>) outside said light guiding material (<NUM>) and to re-direct it inside said light guiding material (<NUM>); and
said light guiding body further comprises a pattern layer (<NUM>) applied to said light guiding material (<NUM>) and being configured to refract said light parallel to said substrate layer (<NUM>) and deviate it along a direction perpendicular to said substrate layer (<NUM>), so as to obtain an emitted light, wherein said pattern layer (<NUM>) comprises a series of protrusions (<NUM>) distributed so as to make the brightness of said emitted light uniform.