GB2436170A

GB2436170A - Cooling or heating device in a chip card reader

Info

Publication number: GB2436170A
Application number: GB0605479A
Authority: GB
Inventors: Vitus Luk
Original assignee: Amstrad PLC
Current assignee: Amstrad PLC
Priority date: 2006-03-17
Filing date: 2006-03-17
Publication date: 2007-09-19
Also published as: GB0605479D0

Abstract

A card reader for a chip card, such as a card for a television set-top box, contains a component to conduct heat away from the microchip on the card. A card reader receives a smart card with an embedded chip 5. The reader communicates data with the smart card chip 5 via electrical contacts 3. To remove heat generated by the chip 5, a thermally conductive component 7 is provided to conduct heat away from the card. The heat conductor 7 may contact the card or may be contactless; it may also extend outside the card reader housing 6. Alternatively, the heat conductor 7 may be used to heat the card to an acceptable operating temperature if it is too cold.

Description

pparatus for increasing or reducing the operating temperature of

electronic component(s)

Field of the Invention

This invention relates to apparatus for reduci ng or incroas mg the ope rati ng Leinperatu re of electronic components embedded on a card, preferably a chip-card.

Background of the Invention

Chip cards are becoming increasingly common and are used by a wide variety of electronic devices. Chip cards comprise a card with an integrated circuit or chip" embeddeci in them. The integrated ci rcuits can both store and process data which is sent to them. Chi.p card readers and wriLers are required to send and receive data from the chip cards and comprise contacting apparatus with a contact element support or frame within which contact elements are fixed] y mounted.

Such a chip card reader is disclosed in German Patent AppLication Number DE-39 31 506.

A set of contacts are provided on one side, allowing the reader to he soldered readi Ly into a printed circui t board to he used in an apparatus in which the chip-card reader is to be used. A cover can be mounted on the contact element support, so as to form Logether with the frame an Lnsert slot into which a chip card can he inserted into a card reading position. The cover is not required if the apparatus in which the chip-card reader is used provides a surface which assumes the function of the cover. In the card reading position the contact elements of the chip-card reader, which are sometimes called reading contact elements, engage or contact the card contacts which are formed on at leat one surface of the chip-card. When a chip-card is inserted into the reading position in the chip-card reader, the information stored in a chip located on the chip-card can be read. It is important for the reading contact elements to maintain good electrical 1O OBU1 contact with the card contacts. In order to do so, the forces of the reading contact elements pushing on the contacts must be carefully controlled, which requires the area of the card where the chip is placed to he held securely by the cover. This means that as a minimum, the cover must exert force directly behind the chip.

Chip-card readers are installed into certain apparatuses, for example television sets, or a Set Top Boxes for the reception of Pay Television. When chip-card readers are installed in Consumer Electronic products, the emphasis is on low-cost chip--card readers, so the frame and cover are preferably made of injection moulded plastic, rather than of metal. Also, the plastic allows Lhe reader to be manufactured to dimensions of high accuracy, and low tolerance, which are required to read the contents of the chip-card itself. The lower the volume of plastic used in the construction of the I rarne and cover, the lower the cost of the chip-card reader. Thus the frame arid cover may often be of open construction, rather than closed, although both types do exist.

Some chip-card readers comprise an assembLy of separate frame and cover. Others are made of a single in3ection-mo]ded part, comprising both frame and cover.

The chi.p-card itself is designed to common dimensions, described by International. Standards, in particular specJ fication number 1S07816 of the International Standards Organisation. When such cards are inserted into chip-card readers, they fill the insert slot between frame arid cover described above, and the sides of the card touch the sides of the card reader. When the card is fully inserted, its end hits the far end of the reader arid operates an ci ectri cal contact, which signa is the presence of the card to associated electronic ci rcuitry. When the card is fully inserted it complet.ely blocks any airflow from the underside of the card to the top-side. The chip-card 1O G}UI readers can be mounted in many orientations, but since they arc usually mounted directly to a printed ci rcuit board (PCR), they are main'y mounted horizontal].y wath the chip on t:he underside of the card, near the PCB.

The chip-card comprises a silicon chip, typically a micro-processor, fixed to a plastic carrier (the card itself) . The chap is powered by supplying a vo'tage to its power terminals via the chip-reader contacts and is abJe to work once supplied with a suitable clock frequency and reset, again via the contacts. The chip executes certain software applications, such as those required Lo secure PayTV entitlements, or electronic purse transactions. As applications become more and more complex, the computationa] processing requirements or the card increase, often requiring higher clock frequencies or more power-hungry processors (chips) . The power consumption of such cards is likely to increase over time and as a direct consequence the power dissipation. This power dissipation is transferrec to heat energy, which causes the chip itself to heat up. The chip is mounted on the plastic card and together with the chip contacts must meet the dimensionaL reql.liremenos of Lhe ISO specification, i.e. they must be sufficiently thin to fit into the insertion slot of the chip-card reader. Thus i.t is not possible to fix a heatsink permanently to the chip-card and the contacts are the only means to transfer heat away from the chip.

Furthermore, all electronic components are designed to work over a clear..ly specified temperature range. When components are assembled into an electronic product, it is important that they operate within their respective ranges.

Such products comprise a cabinet or enclosure, within which printed circuit hoards incorporating a collection oF components are fitted. The components themselves consume power and dissipate heat energy, thus raising the temperature within the cabinet;.

1ThI CP In order for the components to operate within their respective temperature ranges, thermal management techniques are employed. The first technique is to reduce the power consumption of the components themselves, through careful electronic circuit design. The next technique.s typically to manage the ambient temperature experienced by the individual components by cont;rolling the convecL on of air through the cabinet, by the addition of air holes at the bottom, sides and top of the cabinet. Individual components may have thermally conductive heatsinks permanently attached, which increase the surface area over wh ch the air flows. These are bonded to the outer packaging of the component using thermal ly conductive compounds, such as so-called heat-sink compound. These heatsinks have the desired effect of cooling the component more efficient;l. Should convection techniques prove unsatisfactory, Forced- air cooling can be employed through the addi tion of an electronic cooling fan.

The chip of the chip-card, being an electronic component must; operate within its specified operating temperature limits. The way this is managed in a consumer electronic product is through the control of the ambient temperature of the area of the cabinet in which the chip-card reader resides. This is the most simple and cheapest way of managing the temperature to which the card s exposed. it is also usually sufficient, since the heat generation of the chip is usually very low when compared to the heat generated with the enclosure. The ambient temperature within the cabinet or enclosure is considered as being a much more significant; factor than t;he tieat generat;ed by the card itse f. Nevertheless, there are also difficulties in conducting away the heat generated by the card it;self. The card is typically inserted with the chip mounted on the underside arid since the card blocks the card reader slot, little or no airflow takes place from the underside. Above the chip is t;he plastic of the card upon which t:he chi.p is mounted, then possibly an ai gap (given b1flO GO1 that the cover is an imperfect fit to the card), then the thick pLastic of the cover (be iL a full or open cover) None of these elements are good at conducting heat away from the chip.

It is an object of the present: invention to provide a card-reader, which manages the operating temperature to which the chip is exposed by managing the heat generated by the card itself.

It is a further object of the invention to protect the contact reading elements from electrostatic discharge.

IL is a furLher object of the invention to prevent the contact reading elements from being shorted together electric a I I. y.

Summary of the Invention

In accordance with the present invention there is provided apparatus for increasing or reducing the operating temperature of electronic component(s) embedded on a card, the card being irisertable nto an electronic device, the apparatus comprising; a card receiving device to communicate with terminals of the electronic components embedded in the card; and a heat conductive component coupled to the receiving device and; wherein the card when inserted nto the card receiv i.ng dev cc i s so positioned in relation to the heat conductive component that the heat conductive component conducts heat: to or from the electronic components embedded in the card.

in one embodiment, the card and the heat conductive component are in physical contact.

In another embodiment, the card and the heat conductive component are non-contacting.

](O CBOJ

Brief Description of the Drawings

n embodiment of the invention will now be described in detail by way of examp'e only with reference to the accompanyi ng drawings in whi oh: Figure 1 is a top plan view of a conventjonElj chip-card reader in use today; Figure 2 is a cross-sectional elevation view of a chip-card reader with card inserted. The cross secti on is atong line PB of Figure 1; Figure 3 is 0 cross-sectional elevation view of a chip-card reader of an embodiment of the invention; Figure 4 is a cross-sectional elevation view of the chip-card reader of another embodiment of the invention; Figure 5 is a cross sectional elevation view showing 1 5 the posit ona 1 relationsh i.p between the contact reading elements arid thermally conductive cover or component; Figure 6 is a plan view of the holes 11 cut i.nto the thermal ly conductive area of the cover to avoid galvanic contact with the contact reading elements 3; and Figure 7 is a cross sectional devotionaL view along axis CC, showing a card being inserted.

Figure 1 shows a pLan view of a conventional chip-card reader and Figure 2 its corresponding elevational view, with smart card inserted. The chip-card reader comprises a base portion 1 with contact reading elements 3. This particular styLe of cover i.s open but. however other designs of conventional chip card readers have full covers which do not have ho! es through them, so the contact arms 3 are not be visible in the plan view. The central area 6 of the cover 2 covers the chip and contact area so as to ensure the forces hetwen contact reading elements 3 and chip 5 are properly distributed. The chip 5 is fi.xed to the p!asti.c 4 of the chip-card.

The base 1 and the cover 2, 6 are usually made of polycarbonate plastic and injection molded. Thus heat energy from the chip 5 is not conducted away effectively, UL'6 U CPU] since the card 4 and central portion 6 are both of plastic, which has a relatively poor thermal conductivity.

Detailed Description of the Preferred Embodiments of the Invention An embodiment of the invention is shown in Figure 3.

An additional, thermally conductive component 7 is added to the cover around central portion 6 and this conductive component 7 transfers heat, generated by the chip 5, away from the top side of the plastic of the card 4. In this embodiment, the chip on the chip card is actually located on the bottom side of the card, as shown in figure 3. This allows the chip to make contact with the contact reading elements 3 located on the bottom side of the chip card reader. This means that heat generated by the chip has to be conducted away from the chip through the chip card and then to the heat conductive component. As explained below, in one embodiment the chip card is in physical contact with the thermally conductive component. In an alternative embodiment, the chip card and the thermally conductive component are separated by a small air gap.

[n this embodiment, the thermally conductive component comprises one or more sheets of thermally conductive material preferably of high thermal, conductivity. An example of such a material of high thermal conductivity could he a metal or ceramic or glass type material., it is attached to the cover 6 by known fixing techniques such as by using thermally conductive adhesive. The thermally conductive sheet material is attached so that the plane of the sheet i.s subtantiaily perpendicular to the plane of the chip card. Other configurations in which the thermally conductive sheet material is not perpendicular are also envisaged. This allows air to flow past the thermally conductive material and for greater cooling effect since the conductive material has a large area. if two sheets of thermally conductive sheet material are attached to the cover, then preferably, a further sheet of thermally LBU1 conductive material is attached joining the two sheets of thermally conductive material. This further sheet improves the conduction of heat away from the chip and is fixed inbetween the central portion 6 of the cover and the chip card itse]f.

Preferah]y, the apparatus incLudes a cover, the thermally conductive component including a portion which extends from the inside of the card receiving device to the outside of the cover. This allows heat to he conducted from the chip to the outside.

It shouLd he not.:ed that in this embodiment, thermal] y c:ondi.ictive component -Ls not actually in contact with the chip card 4 itselF. Instead, there is a small gap between the chi.p and the cover, and the gap allows the chip card to he inserted into the reader without chip itsel.f coming into contact with the chip card reader cover, which could damage the chip. Preferah]y the gap or distance between the chip and the cover is a small as possible. However, due to practical limitations, the gap between the chip and the thermally conductive component is typicaLly in the range 0. lmm-3mm.

When the hard is fut.ly inserted into the card receiving device, the heat conductive device, on one side of the card is aligned with the position of the chip, which is located on t:he other side of the card.

When the chi..p is at a higher temperature to that of the cover 6, heat will he transferred to the cover by conduction of the heat from the chip via the plastic card La the air immediately next to the heat conductive component 7, and then by conduction of the heat: from the air to the cover. Heat will then flow by conduction from the cover to the thermally conductive component, which is cooled by the transfer of heat by conduction to the surrounding air. Other heat transfer processes such as convect.;ion and radiation will also he responsible for 12u (T3u transferring heat from the chip. Heat transfer mediums other than air such as Helium gas could also be used.

Pre Ferahl.y, the thermal ly conductive component is layer of metal or other material of high heat conducLivity which conducts the heat generated by the chip 5 away, where it is cooled by air.

[n a further embodiment the chip card can be in physical con Loct with the heat conductive component. This embodiment; has the advantage more heat wi Ii be conducted away from the chip card because of the physical contact of the chip card and the heat conductive component.

in a further embodiment, the cover has openings with clearance around portions which extend from inside the card receiving device to outside the card receiving device to allow cooling ai to circulate.

Vi pure 4 shows an embod Lmont of the invention whore the top cover itself 8 and/or additional area 9 is used to dissipate the heat generated by the chip 5, which propagates through the plastic of the card 4. In this embodiment, the centraL portion 6 of the cover is also made out of a thermaJiy conductive material. Heat from the chip will then be transferred to this thermally conductive material, which will he cooled by air passing over it.

Additional thermally conductive components as previously described can also he attached to the central portion 6 which is thermally conductive that are preferably substantially perpendicular to the plane of the chip card and which provide cifl increased surface area over which the air can cool, the thermally conductive mat;erial 6,8.

Figure 5 shows an embodiment of the invention as per Figure 3, but this time highlighting the positional relationship between the component 7 and the card reading elements 3. Wbeh the card 4 has not been inserted it is possible for the rest position of the elements 3 Lo be i.n contact with the cover. When the cover is eLectrically conductive, it is desirable to avoid contact wi th the -10 -1?6O (;flu readinq elements, so holes may be cut in the component or cover so as to create a clearance vo d around the rest position of the elements. The holes are shown in Figure 6, which is a plan view of the component shown in Figure 5.

One embodiment can further comprise an array of conLacts which make electrical contact with the contacts on the chip, and the heat conductive component has openings opposi te the contacts to prevent t;he ci ectri cal contacts COmj ng into contact wi Lb the heat conductive component.

This avoids galvanic connection to Lhe contact reading elements.

Figure 7 shows a partially inserted card. Since the card may be electrostatically charged, it is be possible for the component 7 or thermally conductive cover 6 to become charged, especially if they are electrically conductive. it is undesirable for the charge to discharge through Lhe contact reading elements 3, so the component 7, or cover has been electrical ly connected to a potential (here ground potential) so that any charge on t:he card 4 is discharged prior to it coming close to the conLact reading elements 3. By electrically grounding the heat conducting component, the electro-static charge is conducted away from the contact reading elements.

Although the present invention has been described with reference to a ci.p card reader, those skilled in the art will. appreciate the applicability of an embodiment of the invention to controlling the temperature of any electronic component or device, particularly when it is not possible to use prior art known direct-contact heat si.nk or other cooling methods. Furthermore alLhough the present invention has been described with reference to cooling an electronic component or device, those skilled in the art will appreciate that i.t could equally be applied to heating the :35 e l.ectroni c component or device if the ambient temperature is lower than the operating range of the component. Such an -11 -bi 1) GLU1 embodiment would simply require a heating element to he fixed to te conductive component 7.

Claims

-12 -IJ1

CLAIMS

1. Apparatus for increasing or reducing the operating tempera ture of e fectroni c component (s) embedded on a card, the card being nsert:able into an electronic dcvice, the apparatus comprising; a card receiving device to communicate with terminals of t;he e I.cctrona c components embedded in the card; and a heat conductive component coupled to the receiving TO device and; wherein the card when inserted into the card receiving device is so positioned in relation to the heat conductive component that the heat conductive component conducts heat to or from the electroni.c components embedded i.n the card.

2. Apparatus for increasing or reducing the operating temperature of a card embedded with electronic component(s) according to c aim 1 in which the card receivi ng device is positioned in non-contacting close proxi.mi ty to the heat conductive component.

3. Apparatus for increasing or reducing the operating temperature of a card embedded with electronic componenL(s) according to claim 1 in which the card receiving device is positioned in physical contact with the heat conductive component.

4. Apparatus for increasing or reducing the operating temperature of a card embedded with electronic component(s) according to any preceding claim in which card receiving device further comprises electronic contacts fror making contact with the chip, the contacts positioned on one side of the card receiving device and in which the heat conduct ye device is on the other side of the card recei ving device.

-13 --1 Gft)1 5. Apparatus for increasing or reducing the operating temperature of a card embedded with electronic component (s) according to any preceding claim in which the heat conductive device is aligned with the position of the chip when the card is fully inserted into the card receiving dcv cc.

6. Apparatus for ncreasi nq or reduc nq the operating temperature of a card embedded with electronic component(s) according to any preceding claim in which the heat conductive material is a material of high heat conductivity.

7. Apparatus for increas ing or reducing the operating temperature of a card embedded with electronic component(s) according Lo any preceding claim in which the card comprises a chip card.

8. Apparatus for increasing or reducing the operating Lemperati.ire of a card embedded wj th e I.ectroni.c component (s) according to any preceding c I.airn in which the card is substantially parallel to one surface of the heat conductive component.

9. Apparatus for increasing or reducing the operating temperature of a card embedded with electronic component(s) according to any preceding claim in which the surface of the heat conductive component is substantially paralleL to the card when inserted into the card receiving device.

TO. Apparatus for increasing or reducing the operating temperature of a card embedded with electronic component(s) according to any precedi ng claim i n which the apparatus includes a cover and electronic conductive components including a portion which extends from the inside of the card receiving device to the outside of the card receiving device.

-14 -1: CU1 11. Apparatus for increasing or reducing the operating temperature of a card embedded with electronic component(s) according to any preceding claim in which the card reader further compr ses an array ot cont;acts which make electrical contact with the contacts on the electronic components, and t:he heat conductive component has openings opposite the contacts to prevent the electrical contacts coming into contac:t with the heat conductive component when the card is not in the card receiving device. 1 (.1

12. Apparatus for increasing or reducing the operating temperature of a card eedded wit:h electronic component(s) according to any preceding ci aim in which the card and the conductive component are separated by a distance of substantially 0.5 -3 milli -meters.

13. Apparatus for increasing or reducing the operating temperati.ire oF a card embedded with electronic component(s) according to any preceding claim in which the heal: conductive component is also electrically conductive.

14. Apparatus for increasing or reducing the operating temperature of a card embedded with electronic component(s) according to any preceding claim in which the heat conduct ive component is not electri cally conductive.

15. A card reading apparatus having a card receiving device to communicate with terminais of el.ect;ronic component(s) embedded in a card and apparatus for increasing or reducing the operati ng temperature oF the electronic component (a) embedded on the card when the card is inserted into the device, the apparatus for increasing or reducing he operating temperature including a heat conductive component coupled to the receiving device and; wherei.n the card when inserted into the card receiving device is so posit toned in rd au i.on to the heat conducl:.ve component that the heat conductive component -15 -hl?GU GT3U1 conducts heat to or from the electronic components embedded in the card.

6. pparaLu for Increasing or reducing the operating temperature of a card embedded w th electronic component (s) substanH al'y as herein described wiLh reference to the accompanying drawings.