CN1179221A - Read frame of microcircuit card reader device - Google Patents

Abstract

A reading frame for an apparatus for reading smart cards (C), comprising a body supporting brush contact elements (BC1, BC2) for electrically contacting the conductive pads of a chip on a card (C) inserted into the frame. The frame comprises an electronic circuit connected to at least some of the brush contact elements and connectable to the electronic circuit of the card reader. The electronic circuit on the connector comprises means for controlling the insertion of the card (C) into the card reader and its withdrawal therefrom, and the reading frame comprises an additional brush contact (BCX) or cut-off sensing contact which is offset in relation to the primary brush contacts in the direction in which the card (C) is inserted, and electrically contacts one of the conductive pads (C1, C2) of the smart card (C) whether or not said card has a primary contact.

Description

Read frame of microcircuit card reader device

The invention relates to a reading frame for use with a microcircuit card reader device.

In the context of the present invention, "card" refers to all types of cards incorporating a hybrid or monolithic integrated circuit or "microchip". The term "microcircuit" will be used below. For example, the card is in the form of a "credit card", also known as a "memory card". The card's microcircuits typically include a microprocessor or microcontroller containing memory circuits, such as "programmable read-only (PROM)" type memory. It must be possible to insert this type of card into a dedicated device for reading and/or writing data. For simplicity, these devices will be referred to below as "card readers", it being understood that they are also capable of writing data and ensuring the other auxiliary functions mentioned below (power supply, testing, etc.). Data is stored in the aforementioned memory circuits, generally in encrypted form. Therefore, it is read from or written to memory cells.

Other logical structures are also used, notably for "electronic purse" or similar applications.

In any case there is an input-output element consisting of several contact areas, also called "pads", flush with the surface of one of the main faces of the card. Various standards (ISO, AFNOR, etc.) define the location of these contact areas. They are used not only for the input-output of the aforementioned data, but also for powering microcircuits and performing various checks, depending on the applications involved (existence check, etc.). The card reader comprises a reading frame equipped with several such brush contacts which, when the card is correctly inserted into the reading frame, form electrical contact (galvanic contact) with the aforementioned areas.

Various needs and trends are currently emerging, including:

- the requirement to improve the security of the operation of the reader device; to this end, it is necessary to:

1) Ensure that the card is correctly inserted before the microcircuit is powered on and the dialogue process with the microcircuit begins.

2) Guarantees a quick disconnection of the power supply in case of mishandling or "pulling out" of the card, in order to avoid damage to circuits and/or falsification.

For this purpose, current reading systems include a device for detecting correct insertion of the card using an end of travel contact, the closure of which governs the initialization of the electronic circuit and the activation of the card reader. The electronic circuit controls and monitors the start of the read and write sequence by a microprocessor to meet such a special timing, for which the reader:

- to power up the microcircuit,

- activation of data input/output channels,

- activate the microcircuit clock channel, and

- Execute the microcircuit initialization procedure.

The microcircuit must then respond to the initialization routine in a special way in order to enable dialogue between the card's microcircuit and the reader's microprocessor. At the end of this dialogue, the microprocessor executes the deactivation procedure of the card.

There are several microcontroller-based dedicated circuits that manage these procedures of initializing and terminating the dialogue with the microcircuit along with monitoring the card for overvoltages and short circuits.

However, if the card is removed, power down and deactivation of various channels is required:

1) There are contacts in the circuit breaker card;

2) Before the card is powered off, the detection of this break can be initiated by a logic operation program by the microprocessor or a dedicated microcontroller.

Cards may be pulled out at a rate of up to 1m per second. This requires the card presence contacts to have a travel of less than 0.1 mm to ensure a response time of less than 100 μs compatible with the card emergency deactivation procedure.

The first problem is the usual lack of precision with respect to the position of the end-of-travel contacts, especially if the end-of-travel contacts are horizontal or mounted on a frame separate from the readout frame.

The second problem is that the response time of a microprocessor or microcontroller depends on its internal programming and the frequency of the clock that sequences it.

Applicant has found:

- the card is assumed to be correctly inserted when the end-of-travel contact is activated;

- the initialization procedure begins by applying voltage to the card supply brushes;

——Before power-on and during the initialization phase of the card, the initialization (reset channel) brush is at logic 0 potential;

- During the initialization procedure, the signal brushes are in a so-called "high impedance" state.

Based on these findings, it is an object of the present invention to provide a device for detecting incorrect positioning of the contact areas of a card relative to the brushes, which can be applied to rapidly detect contacts between brushes and contact areas of a card lost.

To this end, according to an important feature of the present invention, such an additional brush contact is provided on the reading frame of the card, which is called a breaker contact and is placed relative to the brush contact common to the brush contacts in the same row. Axis slightly rearward position.

According to a second aspect of the invention, the contact is associated with a logic circuit for rapid detection of card disconnection and deactivation, which logic circuit performs some or all of the following functions:

- set the initialization channel of the card's microcircuit to 0,

- set the signal channels of the card to a high impedance state,

- Cut off the power to the card.

Thus, the invention embodied in a reading frame for a device for reading a microcircuit card comprises a base supporting brush contacts adapted so that when the card is inserted into the The frame constitutes electrical contact with the conductive areas associated with said microcircuit, and is characterized in that it contains an electronic circuit connected to at least some of said brush contacts and adapted to communicate with the reader The electronic circuit connection of the card reader, the electronic circuit carried by the contactor contains means for controlling the insertion of the card into the card reader and the withdrawal of the card from the card reader; and is characterized in that the reading frame contains an additional open circuit detection brush contacts, which are offset relative to the original brush contacts in the card insertion direction and are adapted so as to be in contact with one of the conductive areas of the microcircuit card whether or not the microcircuit card is connected to the original contacts make electrical contact.

Thus, the readout frame according to the invention comprises: the interaction of the electronic circuit described in PCT patent application FR96/00156 filed on January 30, 1996 and an additional brush contact described in EP-A-0 595 305 combined.

In an advantageous embodiment, the sensing frame comprises several original brush contacts providing signal brush contacts, a ground brush contact, and a power supply brush contact.

In a preferred embodiment, the open circuit detector contact can be in electrical contact with the supply brush contact via a supply conductive area.

The present invention will be better understood, and other features and advantages will become apparent, by reading the following description and by referring to the accompanying drawings, in which:

- Figure 1 is a perspective view of a readout frame according to the invention;

- Figure 2 shows a first example of a microcircuit card conforming to the ISO standard, showing the positions of the contacts and their main geometrical characteristics;

- Figure 3 shows the first example of a microcircuit card conforming to the AFNOR standard, showing the positions of the contacts and their main geometrical characteristics;

- Figure 4 shows a first example of a microcircuit card conforming to the ISO standard, the contacts of which have a special structure;

- Figures 5a and 5b show an example of a prior art contactor for a microcircuit card reader;

- Figure 6 shows the layout of the contacts constituting an example of the contactor of the first embodiment of the present invention;

- Figures 7a and 7b are detail views depicting the operation of a contactor adapted to accept cards conforming to the ISO standard;

- Figure 8 shows the dedicated electronics of the card reader associated with the contactor of the invention;

- Figure 9 shows an embodiment of the emergency shutdown logic electronic circuit of the present invention;

- Figures 10a and 10b show a different embodiment of the contactor of the invention.

In the embodiment of Figure 1, the contactor 1 of the device for reading a card C equipped with a microcircuit 3 has a base body 2 supporting several brush contacts B designed such that C, when inserted into the contactor 1, makes electrical contact with the relevant conductive areas of said microcircuit _IC .

According to the invention, the contactor 1 comprises an electronic circuit _IC connected to at least some of said brush contacts _C1 to _C8 and to the electronic circuit 4 of the card reader. The electronic circuit I _C carried by the contactor 1 contains the means for monitoring the insertion and removal of the card C into the reader and described in detail in PCT application FR96/00156.

Figure 2 shows a part of a card C conforming to the ISO7816 standard. This standard specifies the dimensions, positions and assignments of the contact areas _C1 to _C8 which are flush with the surface of the ID-1 type microcircuit card. The card may contain one or more microcircuits. The input-output terminals of these microcircuits are connected to contact areas C ₁ to C ₈ .

The contact areas _C1 to _C8 are arranged in two rows each having four areas, respectively _C1 to _C4 and _C5 to _C8 , the two rows being substantially parallel to each other and to the left edge B of the card C _c (in the figure). This edge acts as a joint. The figure also shows card C's top edge _Bs . Figure 2 also indicates the main geometrical features defining the joints _C1 - _C8 , expressed as the minimum or maximum distances (in millimeters) stated in the aforementioned standard.

As previously indicated, there are 8 joints. They can be located on the front or back of the card C, but the above distances are defined relative to the left edge _BC and the top edge _BS of the card C.

The assignments of the contacts are listed in the table appended to this specification.

Figure 3 shows an example of a microcircuit card C conforming to the old AFNOR standard, using the same representation convention as card C.

With regard to the distance between the contact areas C ₁ to C ₈ and the previously mentioned left and upper edges, there are significant differences. In addition, the position of the contact area is also different. For example, contact C ₈ on the ISO card is in the same position as C ₁ on the AFNOR card.

The contacts used in the card reader must take into account the standard used, this constraint is common to all prior art contacts.

Figures 5a and 5b show, by way of example, a prior art contactor 60 in a cross-sectional view along line BB and in top view, respectively. The brush contacts 50 bent at 63 are arranged in two rows in corresponding holes 66 and 67 . The contactor also includes a pair of "end of travel" detector contacts 20-30 which are bent at 60 and 61. The members 20 and 30 are arranged in a hole 68 and their bent ends are arranged in the hole 68 .

It should be noted that for insertion of a card (not shown) in the direction of arrow F, the front edge 70 (at the top in FIG. 4b ), which is curved, has two side endpoints 71 . These two points 71 define a bonding surface line BB for the card. The area 24 of the contact element 20 adjacent to the engagement surface line BB has a hook-like contour. When the card is fully inserted into the contactor 60, it pushes the contact 20 back, which makes the two contacts 20 and 30 make contact and full insertion of the card ("end of travel") is determined by the card reader associated with the contactor 60. detected by appropriate electronic circuitry (not shown) of the device.

This detection allows the supply voltage to be applied to the brushes associated with area C1 of the card C (see, for example, FIG. 2 ).

According to the present invention, an auxiliary "open circuit detection brush" type contact is added in parallel with the standard "voltage brush" in the following structure. The auxiliary brushes are offset relative to the standard brushes.

Fig. 6 is a schematic diagram showing a contactor 1 for inserting a card C of the present invention. In the example shown in FIG. 6 it is assumed that the card to be inserted into the contactor 1 _conforms to the aforementioned ISO standard.

To simplify the figure, Figure 6 shows only the contacts and their spatial arrangement. Other components: the contactor base and other accessories can be completely shared with all prior art contactors, such as the contactors shown in Figures 5a and 5b.

In a manner known per se, the contactor 1 has two rows, each row containing four brush contacts, respectively B _c1 -B _c4 and B _c5 -B _c8 . Each of these brushes is adapted so as to make electrical contact with a corresponding contact area C ₁ to C ₈ of the card C. They provide the contacts 50 from Fig. 5a.

A pair of "end of travel" contacts _Bfc1 and _Bfc2 may also be provided to detect complete and correct insertion of the card C into the contactor 1 . This is also known per se.

Figure 6 shows brushes _Bc1 - _Bc4 and _Bc5 - _Bc8 as thin, flexible metal diaphragms with distal ends 10 in the shape of hooks. These diaphragms are parallel to each other, and the aforementioned distal ends are opposed to each other in pairs on opposite sides perpendicular to the axis of symmetry A of the diaphragms.

According to an essential feature of the invention, an additional contact B _CX becomes a backup of the contact B _C1 of the "open circuit detection brush" type. During manufacture of the contactor (see Fig. 5b), this additional contact B _CX can be cut from the same strip as the standard contacts and molded into the contactor base at the same time as them. In this case, it is advantageous to reduce the width of a single diaphragm and add a fifth diaphragm to its side.

In all cases, the additional contact B _CX detects the withdrawal of the card C and correspondingly detects the activation and deactivation of the microcircuit card, as will be explained below.

Still in the case of card C conforming to the ISO standard, Figure 7a shows the position of the brush contacts B _C1 and B _CX relative to area _C1 in the normal working position, ie when the card C is correctly inserted into the contactor 1 . In this case, the brush contact B _CX is set back (relative to the center of the card) from the brush contact B _C1 , but above the area _C1 . The card C is pushed by an engaging surface b.

In this normal operating situation, the brush contact B _C1 is connected to the supply voltage V _CC , which is typically +5V. Then zone _C1 is at the same potential, additional contact B _CX "reads" the card's supply voltage V _CC and disables the break logic that starts the card initialization and readout procedure and enables power supply to the card's microcircuits. Read and/or write operations can proceed normally.

If the card is withdrawn, either as a normal withdrawal or as "pull out", zone _C1 is moved in translation in the direction of arrow _FR and brush contact B _CX is the first brush contact that will leave zone _C1 pieces. This situation is shown in Figure 6b.

The voltage "read" by the additional brush contact B _CX tends to disappear via a high/low transition which activates the emergency-off logic electronics.

However, the other contacts B _C2 to B _C8 do not have time to leave their corresponding areas _C2 to _C8 .

Figure 8 is a block diagram of a device for reading ISO-compliant format with 6 contacts (prior art). In this device, the "end of travel" contact fc is connected to the control circuit CrC of the card reader. As soon as the closure of this contact is detected, the control circuit establishes the power supply voltage V _CC of the card through the brush contact B _C1 , and starts the sequence initialization dialogue process between the card reader and the card, which is through the corresponding cards. The brush contact is realized by activating the input/output line I/O used for the dialogue between the card and the card reader to establish the clock CK of the card, and especially deactivating the reset input RST of the card.

Figure 9 shows such a simplified emergency break logic electronic circuit, which uses the additional contact B _CX to immediately stop the dialogue between the reader and the card. For this purpose, the signal from the connection V _CC of the control circuit is connected to the set input "S" of a flip-flop Ba. The clock input CK of the flip-flop Ba activated by a high/low transition is connected to the contact B _CX . The D input of flip-flop Ba is at logic zero level. The inverted output Q is connected to the enable input EN of a buffer circuit through which the card's clock, I/O and programming V _PP channels pass in this example. The inverting output Q of flip-flop Ba, combined with the RST output of the control circuit through an AND gate, is connected to the initialization (reset) brush of the card in contact with zone B _C2 .

The working process of the device is as follows:

When the card is inserted, the end-of-travel brush _fc closes and, as in prior art devices, the detection of this closure by the card reader's control circuit CrC causes the card to obtain the supply voltage V _CC . According to the invention, this closing then sets the emergency disconnection device by setting the flip-flop Ba into a state waiting for a downward transition of the signal from the additional contact B _CX .

When closure of the end-of-travel contact f _c is detected, the control circuit powers up the card, which causes a logic "1" level to appear at the set input "S" of flip-flop Ba. Then flip-flop Ba, independent of the state of the clock input CK, changes from a state where the inverted output terminal is at a logic "1" level to a state of waiting for the falling edge of the clock signal CK.

Therefore, the breaker is set, but it remains transparent to the signals RST, CLK, and I/O because the "Q" and " The Q" output remains in a state that allows these signals - via the buffer circuit T in the case of the signal RST and in the case of the signals CLK and I/O - to pass through the AND gate.

If the card is pulled out, brush B _CX leaves region _C1 and no longer reads voltage V _CC , which causes a high/low transition at flip-flop Ba, causing the output to read at its D input Get the value "0", trigger the following event:

——The output of the AND gate becomes "0", which triggers a "reset" of the microcircuit card C _ard ,

- By deactivating the buffer circuit T, the brushes of the reader carrying the signals CLK and I/O are deactivated.

Thus, the emergency shutdown logic protects the input/output channels of the card until the control circuit detects a fault, cuts off the supply voltage V _CC and enables normal deactivation of the microcircuit card.

Of course, this simplified arrangement described here can be enhanced, inter alia, by provisions for overvoltage protection, anti-bounce devices, etc., of devices well known to the skilled person, and, in particular, can include a circuit breaker for cutting V _CC Additional flip-flops or an additional error detection line connected to the control circuit CrC.

Without departing from the scope of the invention, it is also possible to place an additional wiper contact in front of the area V _CC (relative to the center of the card) but still outside the area V _CC , as shown in Figures 9a and 9b. Card extraction then causes the supply wiper contact B _C1 to contact the additional wiper contact B _CX through area C ₁ , which produces a rising edge which only has to be inverted to obtain an equivalent detector arrangement operation.

Naturally, certain requirements must be met in order for the present invention to be effective. These requirements primarily relate to meeting manufacturing tolerances and tolerances for the position of contact B C1 relative to zone _C1 in the contactor when the card is in the engaged position and there is an offset between the standard contact B _C1 and the additional contact _{B CX} .

To provide a specific example, the center of area C ₁ is located 18.87 mm from card engagement face b with a tolerance of max +0.4 mm min -0.5 mm. As already mentioned, the width of the region C ₁ in the direction parallel to _FR is at least 2 mm, and the distance between C ₁ and a region adjoining C ₁ is 0.2 mm.

When it comes to accuracy, in the case of prior art contactors provided with several "end of travel" type contacts, the guarantee of the correct sequence relies on:

- the mechanical precision of the aforementioned contacts;

- the position of the contact areas relative to the edge of the card;

- the position of the brush contacts relative to the "end of travel" type contacts;

In the case of the contactor according to the invention, the accuracy depends solely on:

- the required deflection of the brush contacts, obtained by a tool cutting and bending the brushes; and

- the accuracy of the width of the contact areas.

The overall accuracy obtained is better than that obtained only with the aid of several "end of travel" type contacts.

appendix contact name and function C ₁ VCC (power supply voltage) C ₂ RST (reset signal) C ₃ CLK (clock signal) C ₄ reserved for future use C ₅ GND (ground) C ₆ VPP (programming voltage) C ₇ I/O (input/output data) C ₈ reserved for future use

Claims (6)

1. A readout frame (1) for a device for reading a microcircuit card (C), comprising a base body supporting a number of such brush contacts (B) adapted to operate on the card (C) ) is inserted into the frame (1) to make electrical contact with the conductive areas associated with said microcircuit, characterized in that it contains an electronic circuit (I _C ) which is at least connected to said brush contacts Some of (B) are connected and adapted to interface with the electronic circuit (4) of the card reader, the electronic circuit (I _C ) carried by the contactor contains the functions for controlling the insertion of the card (C) into the card reader and A device for withdrawing a card (C) from a card reader and characterized in that the reading frame contains an additional break detection brush contact (B _CX ) in the insertion direction of the card (C) The contacts on (F _R ) are offset with respect to the original brush contacts and adapted so that they are compatible with the conductive areas ( _C1 to _C8 ) of the microcircuit card (C) regardless of whether the microcircuit is snapped to the original contacts or not. ) constitutes an electrical contact. 2. A readout frame according to claim 1, characterized in that the original _brush contacts (BC1) constituting the signal brush contacts, a grounding brush contact ( _BC5 ), a power supply brush contact ( _BC1 ) to B _C5 ) are adapted to make contact respectively with the signal conductive areas of the microcircuit card (C), a ground conductive area (C ₅ ), and a power supply conductive area (C ₁ ). 3. Readout frame according to claim 1 or 2, characterized in that said break detection contact (B _CX ) is adapted so as to pass through the microcircuit card (C) corresponding to the original brush contact (B _C1 ) The conductive region (C ₁ ) makes electrical contact with one of the original brush contacts (B _C1 ). 4. Readout frame according to claim 3, characterized in that said break detection contact (B _CX ) is adapted so that when the microcircuit card (C) is engaged by an engagement surface (b) in the readout frame, by Said power supply conductive area (C ₁ ) of the microcircuit card is in electrical contact with the power supply brush contact (B _C1 ). 5. Readout frame according to claim 3, characterized in that said break detection contact (B _CX ) is adapted so that when the microcircuit card (C) is not engaged by an engagement surface (b) in the readout frame, Electrical contact is made with the supply brush contact (B _C1 ) via said supply conductive area (C ₁ ) of the microcircuit card (C). 6. Readout frame according to any one of the preceding claims, characterized in that said break detection contact ( _BCX ) constitutes a trigger signal connected to an emergency break electronics.

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