Protected room with an electrical interruptor and its application

• US 4,785,743 A
• Filed: 12/18/1986
• Issued: 11/22/1988
• Est. Priority Date: 12/20/1985
• Status: Expired due to Fees

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Dalphin, Claude
• Primary Examiner(s): WILSON, NEILL R
• Application Number:
  US06/944,294
• Time in Patent Office: 705 Days
• Field of Search: 109/35, 109/40-42, 109/49.5, 256/10, 340/550, 340/109
• US Class Current: 109/40
• CPC Class Codes: G08B 13/128 the housing being an electronic circuit unit, e.g. memory or CPU chip protecting computer components in secure or tamper resistant housings G06F21/86; protecting computer input devices, e.g. keyboards G06F21/83
• CPC Class Codes: H01H 13/702 with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
• CPC Class Codes: H01H 2231/006 Bank automat; Cash register; Vending machine
• CPC Class Codes: H01H 2239/002 Conductive track to monitor integrity
• CPC Class Codes: H01H 2239/032 Anti-tamper
• CPC Class Codes: H01H 2239/038 Anti-vandalism

Abstract

A protected closed space (L) comprises at least one wall element (E) provided with an electrical interruptor (C1, C2) in turn protected by a thin and flexible probe (S, B) which on the one hand transmits the external mechanical control movement (P) and on the other hand permits the detection of an intrusion at this weak point of the protected closed space. Application: protected closed space with key-board for providing the access code, especially for an electronic payment system.

Claims

1. Apparatus for protecting a closed space, the apparatus comprising:

a plurality of walls defining an interior and an exterior of the space, at least one of the walls containing at least one interruptor which includes first and second conductors and means for producing electrical contact between the first and second conductors in response to a movement, so that binary signals are transmitted from the exterior to the interior of the closed space; and

a probe for detecting attempts at unauthorized intrusion into the space, which probe comprises a comparatively conductive track having at least one relatively thin and flexible part for covering the interruptor, the thin and flexible part acting as a barrier through which the movement is transmitted, so that the probe improves protection in the wall which contains the interruptor without impairing functioning of the interruptor.

2. The apparatus of claim 1 wherein the probe comprises:

a. a flexible insulating support; and

b. conductive ink placed on the flexible insulating support by silk screen printing, so the conductive ink forms the comparatively conductive track and so that the comparatively conductive track has a high electrical resistance, whereby consumption of electrical energy is reduced.

3. The apparatus of claim 2 wherein the probe has an electrical resistance between 2 kΩ

and 50 kΩ

.

4. The apparatus of claim 1 wherein:

a. the comparatively conductive track extends substantially parallel to a first direction X; and

b. the probe comprises a second comparatively conductive track which extends substantially parallel to a second direction Y, the second direction Y being substantially perpendicular to the first direction X.

11. The apparatus of claim 1, 2, 3, 9, or 10, wherein:

a. the comparatively conductive track comprises first and second sub-tracks, the first and second sub-tracks being substantially parallel to one another, whereby the movement activating the interruptor has a substantially equal effect on the conductivity of the first and second sub-tracks and whereby a movement resulting from an attempt at unauthorized intrusion has an unequal effect on the conductivity of the first and second sub-tracks; and

comprising;

b. a balanced Wheatstone bridge coupled with the probe so that the first and second sub-tracks act as impedances of the bridge and so that respective first and second currents in the first and second tracks have opposite polarities, the bridge comprising a differential amplifier for amplifying any unbalance of the bridge and providing a detection signal when there is an unbalance.

12. The apparatus of claim 4, 5, 6, 7, or 8, wherein:

a. the comparatively conductive track and the second comparatively conductive track each comprise first and second sub-tracks, the respective first and second sub-tracks being substantially parallel to one another, whereby the movement activating the interruptor has a substantially equal effect on the conductivity of the respective first and second sub-tracks and whereby a movement resulting from an attempt at unauthorized intrusion has an unequal effect on the conductivity of the respective first and second sub-tracks; and

comprising;

b. a balanced Wheatstone bridge coupled with the probe so that the respective first and second sub-tracks act as impedances of the bridge and so that respective first and second currents in the respective first and second tracks have opposite polarities, the bridge comprising a differential amplifier for amplifying any unbalance of the bridge and providing a detection signal when there is an unbalance.

13. The apparatus of claim 1 wherein

a. the walls form a portable protective case for storing secret information;

b. the probe emits a detection signal in case of intrusion; and

c. the case contains means for destroying contents of the case under control of the detection signal.

5. Apparatus for protecting a closed space, a plurality of walls defining an interior and an exterior of the space, at least one of the walls containing at least one interruptor which includes first and second conductors and means for producing electrical contact between the first and second conductors in response to a movement, so that binary signals are transmitted from the exterior to the interior of the closed space, the apparatus comprising:

a probe for detecting attempts at unauthorized intrusion into the space, which probe comprises a comparatively conductive track having at least one relatively thin and flexible part for covering the interruptor, the thin and flexible part acting as a barrier through which the movement is transmitted, whereby the probe improves protection in the wall which contains the interruptor without impairing the function of the interruptor;

wherein;

a. the comparatively conductive track extends substantially parallel to a first direction X; and

b. the probe comprises a second comparatively conductive track which extends substantially parallel to a second direction Y, the second direction Y being substantially perpendicular to the first direction X; and

wherein the probe comprises;

c. first and second flexible insulating supports; and

d. conductive ink placed on the flexible insulating supports by silk screen printing, so the conductive ink forms the comparatively conductive track and the secondl comparatively conductive track, and so that the comparatively conductive track and the second comparatively conductive track have a high electrical resistance, whereby consumption of electrical energy is reduced.

6. The apparatus of claim 5 wherein the probe has an electrical resistance value between 2 kΩ

and 50 kΩ

.

7. Apparatus for protecting a closed space, a plurality of walls defining an interior and an exterior of the space, at least one of the walls containing at least one interruptor which includes first and second conductors and means for producing electrical contact between the first and second conductors in response to a movement, so that binary signals are transmitted from the exterior to the interior of the closed space, the apparatus comprising:

a probe for detecting attempts at unauthorized intrusion into the space, which probe comprises a comparatively conductive track having at least one relatively thin and flexible part for covering the interruptor, the thin and flexible part acting as a barrier through which the movement is transmitted, whereby the probe improves protection in the wall which contains the interruptor without impairing the function of the interruptor wherein;

a. the comparatively conductive track extends substantially parallel to a first direction X; and

b. the probe comprises a second comparatively conductive track which extends substantially parallel to a second direction Y, the second direction Y being substantially perpendicular to the first direction X; and

wherein the probe comprises a first and second plurality of layers fixed to one another by means of a flexible glue containing a solvent, each plurality of layers comprising the following, fixed together in the order indicated;

a. an opaque layer of aluminum;

b. an insulating layer of polyester;

c. a layer comprising the comparatively conductive track, wherein the comparatively conductive track is formed by silk screen printing ink on a base of laminar silver, whereby the conductive track layer is of discontinuous thickness;

d. a layer of polymerized insulating varnish, which remains flexible after polymerization;

whereby the probe is flexible and opaque and whereby each of layers a-d are separated by one of a plurality of layers of glue.

8. The apparatus of claim 7 wherein:

a. the aluminum layer has a thickness between 7 μ

m and 20 μ

m;

b. the insulating polyester layer has a thickness between 15 μ

m and 30 μ

m;

c. the comparatively conductive track has a thickness between 4 μ

m and 15 μ

m;

d. the varnish layer having a thickness between 10 μ

m and 40 μ

m;

e. the glue layers each having a thickness of less than 10 μ

m, whereby the thickness of the glue layers is negligible;

whereby the probe has a thickness between 40 μ

m and 150 μ

m.

9. Apparatus for protecting a closed space, a plurality of walls defining an interior and an exterior of the space, at least one of the walls containing at least one interruptor which includes first and second conductors and means for producing electrical contact between the first and second conductors in response to a movement, so that binary signals are transmitted from the exterior to the interior of the closed space, the apparatus comprising:

a probe for detecting attempts at unauthorized intrusion into the space, which probe comprises a comparatively conductive track having at least one relatively thin and flexible part for covering the interruptor, the thin and flexible part acting as a barrier through which the movement is transmitted, whereby the probe improves protection in the wall which contains the interruptor without impairing the function of the interruptor

wherein the probe comprises a plurality of layers fixed to one another by means of a flexible glue containing a solvent, the plurality of layers comprising the following, fixed together in the order indicated;

a. an opaque layer of aluminum;

b. an insulating layer of polyester;

c. a layer comprising the comparatively conductive track, wherein the comparatively conductive track is formed by silk screen printing ink on a base of laminar silver, whereby the conductive track layer is of discontinuous thickness;

d. a layer of polymerized insulating varnish, which remains flexible after polymerization;

whereby the probe is flexible and opaque and whereby each of layers a-d are separated by one of a plurality of layers of glue.

10. The apparatus of claim 9 wherein:

a. the aluminum layer has a thickness between 7 μ

m and 20 μ

m;

b. the insulating polyester layer has a thickness between 15 μ

m and 30 μ

m;

c. the comparatively conductive track has a thickness between 4 μ

m and 15 μ

m;

d. the varnish layer having a thickness between 10 μ

m and 40 μ

m;

e. the glue layers each having a thickness of less than 10 μ

m, whereby the thickness of the glue layers is negligible;

whereby the probe has a thickness between 40 μ

m and 150 μ

m.