DE102008005442B4 - Tamper-proof keyboard - Google Patents

Abstract

Tamper-proof keyboard comprising: an actuation panel with a plurality of keys (2, 3); a drilling protection film (5, 30) arranged underneath, which has a conductor track network (7) on its side facing away from the actuation field, which is set up to have a signal current flowing through it, such that an interruption in the conductor track network (7) can be detected by means of a signal current circuit; a layer structure arranged underneath made of several foils (14, 17); and at least one switching foil (19) which is arranged under the layer structure (14, 17) and has a plurality of switching contacts (20, 21) which can be lift-actuated by spring washers (16) which are operatively connected to the buttons (2, 3), the anti-drilling foil (5, 30) has at least one first safety contact (9) on its side facing the switching foil (19), to which at least one opposite second safety contact (13) is assigned, which is arranged on a contact foil (12) arranged above the switching foil (19) is, wherein the at least one pair of safety contacts (9, 13) is spring-loaded by means of the spring washers (16), so that the at least one pair of safety contacts (9, 13) is closed when the keyboard is assembled as intended and when it is disassembled for the purpose of manipulation Keyboard is open, so that a manipulation attempt can be detected by means of a signal circuit.

Description

The invention relates to a manipulation-protected keyboard, in particular the invention relates to protection against manipulation foil switch panels.

Film control panels are also used, among other things, in vandal-resistant stainless steel keyboards for cash dispensers and for payment transactions as electrical contact elements. In these applications, it increasingly comes to the requirements that the structure should be protected against manipulation, so that the reading of the pin numbers by a mechanical conversion of the keyboards or the introduction of a foreign sensor in the keyboard structure is no longer possible. By means of the keyboard according to the invention, film switches can be protected by an additionally integrated contact foil - referred to below as a security foil which is printed with strip meander.

• – Basiskleber
• – Schaltlage mit bedruckten Leiterbahnen (nachfolgend auch Schaltfolie genannt)
• – Distanzfolie
• – Haltefolie.

The actual film switch has been used as state of the art for many years in industrial applications. It usually consists of:

• - basic adhesive
• - Switching position with printed strip conductors (also referred to below as switching foil)
• - spacer foil
• - Holding film.

With the subject of DE 103 40 289 A1 It is generally known to protect hardware modules with a security device. This safety device consists of a hard plastic safety cap, on the inside of which at least two closely adjacent conductor tracks are attached. If drilled through such a safety cap, then the traces are interrupted and the previous signal flow through these traces is thus prevented. This can trigger an alarm.

However, such an arrangement is not suitable for the protection of foil panels in input keyboards, because the conductor network is arranged on the inside of a hard, immovable plastic cap.

Likewise it is from the DE 36 32 144 A1 It is known to print thin film tracks on storage media to provide a conductive thin film. This prevents that a CMOS RAM memory device can be drilled or opened in any other way.

From the DE 196 00 769 A1 is a security module with one-piece security film has become known. Here, a Bohrschutzfolie surrounds a security module. This can only be ensured that the security module itself is not damaged. However, from this document is not apparent how to protect input keyboards with foil panels against attack from the outside.

The object of the invention is a protection of the contact elements of input keyboards against mechanical attack.

The solution of the problem is solved by the technical teaching of claims 1 and 2.

The panel is inventively covered by at least one additional additional security film, which is positioned over the entire surface of the switch contacts.

In this case, the invention allows several ways to integrate the Bohrschutzfolie invention in one or more layers of the layer structure of the keyboard. Importantly, the anti-drilling foil also covers the movable portions of the keyboard, that is, particularly the stroke-actuated portions of the contacts in any layer of the assembly.

It should be emphasized that the additional switching position is performed so thin that the tactility of the attached below switch panels is not adversely affected. In the areas to be protected, a conductor track structure is applied to the top and / or on the back of the security film. By the design of the tracks is detected by an appropriate sensor, whether tracks are interrupted or short circuits caused by the introduction of conductive bodies, as z. B. during drilling / drilling of the structure arises.

• – Basiskleber
• – Schaltlage mit bedruckten Leiterbahnen
• – Distanzfolie
• – Haltefolie
• – Sicherheitsfolie (auch Bohrschutzfolie genannt).

Structure of the protected membrane switch:

• - basic adhesive
• - Switching position with printed conductor tracks
• - spacer foil
• - Holding film
• - Safety film (also called Bohrschutzfolie).

1st variant:

Important in the present invention is that the structure of the film control panel with security film (Bohrschutzfolie) over the entire surface also extends over the switch contacts and their moving parts. This makes it possible for the first time that you can press through a flexible Bohrschutzfolie through the appropriate switching contacts a foil panel. This was not known yet. The prerequisite for this is that a very thin conductor track network is printed on a relatively thin carrier film, wherein the conductor track network either on the top or at the bottom of the carrier film can be printed or printed on both sides.

It is important that the carrier film has a very small thickness of z. B. 75 microns (0.075 mm) and is so flexible that a pressure on any, arranged above actuator button is passed through this Bohrschutzfolie through to the underlying foil panel.

It does not matter how the operation of the keyboard is done and how the keyboard is designed. It can either be provided as a keypad silicone existing safety mat or it can also be provided individual keys that z. B. made of stainless steel are installed in a corresponding stainless steel frame.

2nd variant:

In one embodiment of the present invention, it is provided that the invention, flexible Bohrschutzfolie, which also extends over the actuating surfaces of the foil panel, in addition to the bottom is still provided with (at least) a safety contact on the contact a flexible spring washer rests, the sits with her foot on the actual switching foil.

In the mounted state of the keyboard (using the first variant of the Bohrschutzfolie) is pressed upon actuation of the keyboard, the respective spring plate associated with the respective contact and the two oppositely arranged contacts are closed.

Once the structure is taken apart or destroyed by an attack from the outside, the Bohrschutzfolie is lifted due to the spring force of the spring washer from the contact on the switching foil, the two contacts move away from each other and an intermediate signal flow is interrupted.

Thus, the Bohrschutzfolie invention also provides protection against removal of the panel, in particular against removal of the switching film, which is arranged at the bottom of the structure.

3rd variant:

In a further variant of the present invention, it is additionally provided that in addition to (or instead of) the previously described spring-loaded contact between the underside of the Bohrschutzfolie and the top of the switching foil at least one further contact pair is present.

This contact pair in turn consists of a contact, which is preferably arranged on the underside of the Bohrschutzfolie and the opposite a contact foil is arranged, which is arranged above the switching foil, but below the Bohrschutzfolie.

It is important that this pair of contacts is always closed by the spring force of the overlying keyboard control. Such a force can be exercised either by the elasticity of a silicone mat in which the keys are arranged, or by corresponding spring-loaded individual keys, the z. B. are made of stainless steel.

As long as the keys are not actuated, their spring force acts on the top of the Bohrschutzfolie so that the contact on the bottom of the Bohrschutzfolie in combination with the two contacts on the top of the underlying switching film always remains closed.

If a single key removed or the keyboard foil, then it comes to the opening of said contacts and the intermediate signal path is interrupted and leads to an alarm.

In this way, the invention consists of a total of three variants of a Bohrschutzfolie, all taken alone, but also in combination with each other are functional and considered to be essential to the invention.

• 1. Bohrschutzfolie, die auch über die beweglichen (betätigbaren) Teile der Tastatur gelegt ist.
• 2. Bohrschutzfolie mit einem oder mehreren federbelasteten Kontakten, wobei der eine Kontakt an der Unterseite der Bohrschutzfolie und der gegenüberliegende Kontakt an der Schaltfolie angeordnet ist. Dieses Kontaktpaar ist stets geschlossen und wird nur bei einem Angriff auf oder einem Ausbauversuch der Schaltfolie geöffnet und unterbricht einen Signalstromkreis.
• 3. Bohrschutzfolie mit einem oder mehreren federbelasteten Kontakten, wobei der eine Kontakt an der Unterseite der Bohrschutzfolie und der andere Kontakt auf einer zweiten Schaltfolie angeordnet ist, die im Schichtenaufbau oberhalb der in Ziffer 2 genannten Schaltfolie sitzt. Dieses Kontaktpaar ist stets geschlossen und wird nur bei Angriff (Ausbauversuch) auf eine Taste geöffnet und unterbricht einen Signalstromkreis.

The variants described above are summarized as follows:

• 1. Drill protection film, which is also placed over the movable (operable) parts of the keyboard.
• 2. Bohrschutzfolie with one or more spring-loaded contacts, wherein the one contact on the underside of the Bohrschutzfolie and the opposite contact is arranged on the switching foil. This contact pair is always closed and is only opened in an attack on or a removal attempt of the switching foil and interrupts a signal circuit.
• 3. Bohrschutzfolie with one or more spring-loaded contacts, wherein the one contact is arranged on the underside of the Bohrschutzfolie and the other contact on a second switching foil, sitting in the layer structure above the switching foil mentioned in paragraph 2. This pair of contacts is always closed and will open only when attack (removal attempt) on a button and interrupts a signal circuit.

• – Sicherheitsfolie auch über Folienschaltfelder ohne taktile Rückmeldung (ohne Kontaktfederscheiben);
• – Sicherheitsfolien über Schaltfelder mit mechanischen Kurzhubtasten/Leiterplatten;
• – Sicherheitsfolien hergestellt aus gedruckten flexiblen Schaltlagen aus Polyester, PEN oder anderen flexiblen Folienmaterialien;
• – Sicherheitsfolien hergestellt aus geätzten flexiblen Schaltlagen aus Kapton, Polyimid oder anderen flexiblen Materialien;
• – Sicherheitsfolie mit/ohne Druckkontaktierungen;
• – Sicherheitsfolien mit ein, zwei oder mehreren Leiterbahnzügen mit beliebigem Layout;
• – Sicherheitsfolien mit mehrmalig auch kreuzenden Leiterbahnzügen;
• – Aufbau, bei dem der elektrische Kontakt von der Sicherheitsfolie mittels Federscheiben auf die Schaltlagenfolie übertragen wird;
• – Sicherheitsfolie integriert in Edelstahl/Metalltastaturen, Kunststofftastaturen;
• – Sicherheitsfolie integriert in Folientastaturen;
• – Sicherheitsfolie mit einem Isolationsdruck anstatt der Isolierfolie 8.

Further embodiments with regard to the drilling protection film are:

• - Safety film also on foil panels without tactile feedback (without contact spring washers);
• - Safety films via switch panels with mechanical short-stroke keys / printed circuit boards;
• - Security films made of printed flexible circuit layers of polyester, PEN or other flexible film materials;
• - Security films made of etched flexible switch layers of Kapton, polyimide or other flexible materials;
• - Security foil with / without pressure contacts;
• - Security films with one, two or more traces with any layout;
• - Security films with multiple intersecting conductor trains;
• - Structure in which the electrical contact is transmitted from the security film by means of spring washers on the switch sheet film;
• - Safety film integrated in stainless steel / metal keyboards, plastic keyboards;
• - Safety film integrated in membrane keyboards;
• - Security film with an insulation pressure instead of the insulating film 8th ,

Furthermore, it is shown below how an additional electrical contact can be realized directly over the contact spring discs by the above-mentioned second switching foil. In the assembled operation of the keyboard, this safety contact is always closed. However, if the preload is reduced by dismantling the foil or a key tappet located above it, this safety contact opens. By an appropriate evaluation of this opening can be detected.

• – Sicherheitsfolie in Folientechnik über Folienschaltfelder mit geprägten Domen;
• – Sicherheitskontakte in Folientechnik auch über Folienschaltfelder ohne taktile Rückmeldung (ohne Kontaktfederscheiben);
• – Sicherheitskontakte in Folientechnik mit mechanischen Kurzhubtasten/Leiterplatten;
• – Sicherheitskontakte in Folientechnik, hergestellt aus gedruckten flexiblen Schaltlagen aus Polyester, PEN oder anderen flexiblen Folienmaterialien;
• – Sicherheitskontakte in Folientechnik, hergestellt aus geätzten flexiblen Schaltlagen aus Kapton, Polyimid oder anderen flexiblen Materialien;
• – Sicherheitskontakte in Folientechnik mit/ohne Durchkontaktierungen;
• – Sicherheitskontakte in Folientechnik mit ein, zwei oder mehreren Leiterbahnzügen;
• – Sicherheitskontakte in Folientechnik mehrmalig auch kreuzende Leiterbahnzügen;
• – Aufbau, bei den der elektrische Kontakt von der Sicherheitsfolie mittels Federscheiben auf die Schaltlagenfolie übertragen wird.
• – Eine Kontaktfläche aus Silikonfolie oder Silikonformteile mit Karbon-Kontaktpillen ausgeführt ist.

Further embodiments with respect to the second switching foil are:

• - Safety film in foil technique on foil panels with embossed domes;
• - Safety contacts in foil technology also via foil panels without tactile feedback (without contact spring washers);
• - Safety contacts in foil technology with mechanical short-stroke keys / printed circuit boards;
• - Safety contacts in film technology, made of printed flexible switch layers made of polyester, PEN or other flexible film materials;
• - Safety contacts in foil technology, made of etched flexible switching layers of Kapton, polyimide or other flexible materials;
• - Safety contacts in foil technology with / without vias;
• - Safety contacts in foil technology with one, two or more conductor tracks;
• - Safety contacts in foil technology several times also crossing conductor tracks;
• - Structure in which the electrical contact is transmitted from the security film by means of spring washers on the switch sheet.
• - A contact surface of silicone foil or silicone moldings is executed with carbon contact pills.

In the following the invention will be explained in more detail with reference to several illustrative drawings.

Show it:

1 : Perspective and schematized drawn structure of a foil panel with a flexible Bohrschutzfolie;

2 a section through a foil panel with a Bohrschutzfolie after 1 However, the two other variants of the present invention are also shown;

3 FIG. 2 is a schematic section through the drilling protection film according to the invention as shown in FIG 2 ;

4 : the plan view of the Bohrschutzfolie after 3 ;

5 : the perspective view of the film structure as shown in 2 ,

In 1 is the later also referred to as contact foil Bohrschutzfolie only as Bohrschutzfolie 30 referred to, because according to the first variant no contact agent on the underside of Bohrschutzfolie 30 are arranged. Such contact agents are only in 2 . 3 and 5 disclosed.

Overall is in 2 just a keypad 1 indicated, which may consist of a silicone mat with individual embedded in silicone switch contacts.

Instead of such an actuator and separate operation buttons can be used, which are used in a conventional manner in a rigid support frame and there spring-loaded due to spring washers are kept in the rest position.

It is therefore only schematically shown that the keys 2 . 3 downwards in the direction of the arrow, in each case one switching contact on the switching foil ( 19 ).

This shows the 2 that the keypad 1 with an adhesive layer 4 on the drill protection film 30 according to 1 is glued on. At the top and / or at the bottom of the Bohrschutzfolie 30 Here is a conductor network 7 printed, which consists of a plurality of closely spaced interconnects, which are traversed by a signal current. If one of the tracks is disconnected by an attack or tampering, the signal will be interrupted and an alarm will sound. Because the Bohrschutzfolie 30 also spans the moving parts of the keyboard, it is particularly flexible and can press the buttons 2 . 3 pass down without further resistance.

This shows the 1 that the pressure on the drill protection film 30 on a holding foil 14 is given the appropriate breakthroughs 15 having. Through these breakthroughs protrude spring washers 16 through, which are curved and a certain spring force up on the button, not shown 2 . 3 exercise to keep them in the open state.

The spring washers 16 are here in appropriate shots of a spacer film 17 arranged the breakthroughs 18 having. Under the spacer film 17 is the actual switching foil 19 with the associated contacts 20 . 21 arranged. In the area of these contacts 20 . 21 the actual switching process takes place.

Will the spring washer 16 by a push of a button 2 . 3 Pressed from above, it comes to an elastic deformation and it lies down contact the surface of the contacts 20 . 21 at.

Below the switching foil 19 Here is a base adhesive film 22 arranged, which fixes the entire structure on a support plate.

Important for 1 As a result, a very flexible anti-drilling foil 30 also over the spring washers 16 and the breakthroughs 15 the holding foil 14 is taut, so as to protect these actuating surfaces against damage or penetration by drilling tools or other means. This was not known in the prior art.

Based on 2 Now other variants of the invention Bohrschutzfolie 30 shown.

Out 4 initially results that on a carrier foil 6 a ladder network 7 is printed.

The representation in 2 on the left side now shows a Ausbauschutz against removal of the lower switching foil 19 , It can be seen that at the bottom of the Bohrschutzfolie 5 at least one safety contact 24 is arranged, at the spring loaded a spring washer 25 invests.

In the installed state of the keyboard thus sets the spring washer 25 (which is drawn for exaggeration reasons greatly exaggerated) contact giving to the lower safety contact 23 on top of the switching foil 19 at. This is constantly in the assembled state, the contact pair 23 . 24 kept closed. Is thus upgraded something up or is the switching film 19 expanded downwards, this contact becomes 23 . 24 opened and it leads to an alarm.

As a further variant (third embodiment) is the representation in 2 On the right side. This is partly also in 3 represents.

Important here is that at the bottom of the Bohrschutzfolie 5 each safety contacts 9 are arranged exactly in alignment above the respective spring washer 16 are arranged. This results in a special protection for each contact in conjunction with an underlying contact foil 12 , on the safety contacts 13 are arranged.

Between the upper protection foil 5 and the underlying contact foil 12 Here is an adhesive film 10 arranged which breakthroughs 11 Are defined.

The 3 still shows that the conductor network 7 downwards through an electrically insulating insulating film 8th is covered.

When assembled, the upper safety contact closes 9 the lower safety contacts 13 on the contact foil 12 short, so that always in the assembled state, protection against removal of the buttons 2 . 3 consists.

Namely, one or more of the keys 2 . 3 expanded, then lacks the spring force with which the keys 2 . 3 The contacts 9 . 13 bring in closing contact and thus remove the contacts in such an expansion 9 . 13 and the signal flow is interrupted. This provides protection against removal of the button.

It is important that this protection against removal of the key at the same time also with the characteristics of the Bohrschutzfolie 30 is provided so that also through the recess 15 through which the button 2 . 3 through the retaining film 14 through to the spring washer 16 acts, absolute protection against removal and damage is given. This was previously unknown in the prior art.

Every press of the button 2 . 3 is thus on the spring washer 16 passed and the spring washer then stretches and there is a contact between the contacts 20 and the center contact 21 by elastic deformation of the spring washer 16 ,

These relationships are in 5 shown in more detail. There is shown in perspective that the Bohrschutzfolie 30 now as a drill protection film 5 is formed, wherein the contacts 9 . 24 down towards the switching foil 19 Act.

The lower contact foil 12 with the safety contacts attached there 13 is also so flexible that a corresponding pressure by the respective button 2 . 3 through the drill protection film 5 and through the contact foil 12 down the spring washers 16 can deform elastically.

Because of the safety contacts 13 are designed as elastically bendable tab, the flexibility in the area of the movable surfaces of the lower contact surface is substantially increased.

LIST OF REFERENCE NUMBERS

1

Keypad, operating field

2

button

3

button

4

adhesive layer

5

Drill protection film (top)

6

support film

7

Trace network

8th

insulation

9

upper safety contact (protection against removal button)

10

adhesive film

11

breakthrough

12

Contact foil (below)

13

safety contact

14

wrap

15

breakthrough

16

spring washer

17

shim

18

breakthrough

19

switching foil

20

Contact

21

center contact

22

Based adhesive film

23

Safety contact (below)

24

Safety contact (top, protection against removal of switch panel)

25

spring washer

30

Bohrschutzfolie

Claims (5)

Tamper-proof keyboard comprising: an operating field ( 1 ) with several buttons ( 2 . 3 ); an underlying drill protection film ( 5 . 30 ), which on its side facing away from the operating field, a conductor track network ( 7 ), which is configured to be traversed by a signal current, such that an interruption of the interconnect network ( 7 ) is detectable by means of a signal current circuit; an underlying layer structure of several films ( 14 . 17 ); and at least one under the layer structure ( 14 . 17 ) arranged switching foil ( 19 ), which has several switching contacts ( 20 . 21 ), which can be accessed by 2 . 3 ) in actively connected spring washers ( 16 ) are lift-actuated, characterized in that the drilling protection film ( 5 . 30 ) at its the switching foil ( 19 ) facing side at least a first safety contact ( 9 ), the at least one opposite second safety contact ( 13 ) assigned to one above the switching foil ( 19 ) arranged contact foil ( 12 ), wherein the at least one pair of safety contacts ( 9 . 13 ) by means of spring washers ( 16 ) is spring-loaded such that the at least one pair of safety contacts ( 9 . 13 ) is closed when properly assembled keyboard and is opened at the purpose of manipulation disassembled keyboard, so that a manipulation attempt is detectable by means of a signal circuit. Tamper-proof keyboard comprising: an operating field ( 1 ) with several buttons ( 2 . 3 ); an underlying Bohrschutzfolie ( 5 . 30 ), which on its side facing away from the operating field, a conductor track network ( 7 ), which is configured to be traversed by a signal current, such that an interruption of the interconnect network ( 7 ) is detectable by means of a signal circuit; an underlying layer structure of several films ( 14 . 17 ); and at least one below the layer structure ( 14 . 17 ) arranged switching foil ( 19 ), which has several switching contacts ( 20 . 21 ), which can be accessed by 2 . 3 ) in actively connected spring washers ( 16 ) are stroke-actuated, characterized in that the Bohrschutzfolie ( 5 . 30 ) at its the switching foil ( 19 ) facing side at least a first safety contact ( 24 ), at the contact a spring washer ( 25 ), such that the first safety contact ( 24 ) is spring-loaded, wherein the first safety contact ( 24 ) at least one opposite second security contact ( 23 ) attached to the drilling protection film ( 5 . 30 ) facing side of the switching foil ( 19 ) is arranged, wherein when properly assembled keyboard, the spring washer ( 25 ) contacting the second safety contact ( 23 ) is applied such that at least one pair of safety contacts ( 23 . 24 ) with the spring washer ( 25 ) forms a closed contact, which is opened at the purpose of manipulation disassembled keyboard, so that a manipulation attempt is detectable by means of a signal circuit. Input keyboard according to claim 1, characterized in that the spring washers ( 16 . 25 ) have a curvature and the film ( 14 ) of the layer structure ( 14 . 17 ) a holding foil ( 14 ), the breakthroughs ( 15 ), through which the bulges of the spring washers ( 16 protrude and exert a spring force such that the at least one pair of safety contacts ( 9 . 13 ) is closed and in the unactuated state of the keys ( 2 . 3 ) the associated switching contacts ( 20 . 21 ) are open. Input keyboard according to claim 3, characterized in that the film ( 17 ) of the layer structure ( 14 . 17 ) a spacer film ( 17 ), the breakthroughs ( 18 ), in which the spring washers ( 16 ) are arranged. Input keyboard according to one of claims 3 to 4, characterized in that the flexible Bohrschutzfolie ( 30 ) also about the breakthroughs ( 15 ) of the holding foil ( 14 ) with the spring washers ( 16 ) is arranged.

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