Intruder-detection system for room security

• US 4,760,381 A
• Filed: 12/19/1985
• Issued: 07/26/1988
• Est. Priority Date: 12/22/1984
• Status: Expired due to Fees

• Current Assignee: Telenot Electronic GmbH
• Original Assignee: Telenot Electronic GmbH
• Inventors: Haag, Guenter
• Primary Examiner(s): Orsino, Joseph A.
• Assistant Examiner(s): TUMM, BRIAN
• Application Number:
  US06/810,749
• Time in Patent Office: 950 Days
• Field of Search: 340/541, 340/550, 340/552, 340/555, 340/556, 340/565, 340/567, 340/600, 250/341, 250/349, 250/221
• US Class Current: 340/556
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G08B 13/19 using infrared-radiation detection systems G08B13/194 takes precedence
• CPC Class Codes: G08B 13/193 using focusing means

Abstract

In this system for the securing of rooms, one or more transmitting elements emit suitably modulated light pulses into given regions or sectors which are produced by specially shaped optical components and/or by a special alignment of the transmitting elements and/or by the application of absorbent layers to an infrared filter which is located in front of the transmitting elements and receiving elements. One or more receiving elements receive the incident radiation. Changes in the radiation field with respect to intensity and/or speed of change of the intensity and/or phase are processed in subsequent evaluation logic circuitry. The room security system can also be combined into a larger unit with common evaluation logic.

Claims

1. A security system comprising one infrared-transmitting element and at least two detector elements producing individual electrical output signals in response to infrared radiation within the wavelength region of said transmitting element, means mounting said transmitting element for directionally limited response in a plurality of angularly spaced intruder-response sectors which span a space field to be protected, said mounting means also mounting said detector elements in spaced relation laterally of said transmitting element and such that the response of each of said detector elements fully laps said space field;

electronic means including means sampling and storing the output signals of said detector elements in alternation, evaluating means connected to evaluate currently sampled values against stored values in keyed alternation; and

threshold-operated alarm means connected to produce an alarm-signal output only upon concurrent evaluation of at least a predetermined difference in value for currently detected vs. stored signals in both a keying interval for one detector element and the successive keying interval for the other detector element.

10. The system of any one of claims 1, 2, 3, 4, 5, and 7, in which said evaluating means further includes a threshold-operated indicator connected to produce a disturbance indication only upon occurrence of a single evaluation of said predetermined difference to the exclusion of another current such evaluation of said predetermined difference.

11. The system of any one of claims 1, 2, 3, 4, 5, and 7, in which a barrier element is interposed between each adjacency of a detecting element to a transmitting element.

12. The system of any one of claims 1, 2, 3, 4, 5 and 7, in which said sectors are spaced to an extent which is substantially the effective angular width of a sector.

14. The system of any one of claims 1, 2, 3, 4, 5, and 7, in which each said subsystem includes a mask that is apertured to define said sectors.

2. A security system comprising at least two like infrared transmitting elements and one infrared detector element producing an electrical output signal in response to infrared radiation within the wavelength region of said transmitting elements, means mounting said detector element for directionally limited response in a plurality of angularly spaced intruder-response sectors which span a space field to be protected, said mounting means also mounting said transmitting elements in spaced relation laterally of said detector element and such that the irradiation response of each of said transmitting elements fully laps said space field;

electronic means including means keying the excitation of said transmitting elements in alternation, evaluating means connected to sample and store detected values for first keying intervals for one transmitting element in alternation with separate sampling and storage of detected values for second keying intervals of the other transmitting element, said evaluating means being connected to separately evaluate currently sampled values against stored values for said first and second keying intervals, and threshold-operated alarm means connected to produce an alarm-signal output only upon concurrent evaluation of at least a predetermined difference in value for detected vs. stored signals in both of said keying intervals.

13. The system of any one of claims 2, 4, 5 and 7, in which said transmitting elements are modulated to produce code-modulated pulses of infrared radiation.

3. A security system comprising first and second transmitting subsystems wherein each subsystem comprises an infrared-transmitting element mounted for directionally limited response in a plurality of angularly spaced intruder-response sectors which span a space field to be protected, said subsystems being mounted in laterally spaced proximity with equal numbers of intruder-response sectors and with corresponding sectors of the respective subsystem oriented in laterally offset proximity and for response to said space field;

at least two detector elements producing individual electrical output signals in response to infrared radiation within the wavelength region of said transmitting subsystems and mounted in spaced adjacency to each other and to said transmitting subsystems such that the response field of each of said detector elements fully laps said space field;

electronic means including means sampling and storing the outputs of said detector elements in alternation, evaluating means connected to evaluate currently sampled values against stored values and in alternation synchronized with said keyed alternation; and

threshold-operated alarm means connected to produce an alarm-signal output only upon concurrent evaluation of at least a predetermined difference in value for currently detected vs. stored signals in both of said keying intervals.

4. A security system comprising first and second detecting subsystems wherein each subsystem comprises at least one infrared-responsive detector element mounted for directionally limited response in a plurality of angularly spaced intruder-response sectors which span a space field to be protected, said subsystems being mounted in laterally spaced proximity with equal numbers of intruder-response sectors and with corresponding sectors of the respective subsystems oriented in laterally offset proximity and for response to said space field;

at least two laterally spaced transmitting elements for transmitting infrared radiation within the response wavelength region of said detector elements, said transmitting elements being mounted in spaced adjacency to said detecting subsystems and such that each of said transmitting elements can irradiate said space field;

electronic means including key means keying said transmitting elements for alternating transmission, means for sampling and storing the separate output of said detector elements in keyed synchronism with the keying of said transmitting elements, evaluating means connected to evaluate currently sampled values against stored values in alternation synchronized with said keyed alternation; and

threshold-operated alarm means connected to produce an alarm-signal output only upon concurrent evaluation of at least a predetermined difference in value for currently detected vs. stored signals in both of said keying intervals.

5. A security system comprising first and second transmitting subsystems wherein each subsystem comprises at least one infrared-transmitting element and wherein the subsystem is mounted for directionally limited response in a plurality of angularly spaced intruder-response sectors which span a space field to be protected, said intruder-response sectors being spaced by at least substantially three times the angular width of a single intruder-response sector, and the mounting of said subsystems being such that the intruder-response sectors of one subsystem are in substantially uniformly spaced interlace with the intruder-response sectors of the other system in their mutual coverage of said field;

at least two detector elements producing individual electrical output signals in response to infrared radiation within the wavelength region of said transmitting subsystems and mounted in spaced adjacency to each other and to said transmitting subsystems such that the response field of each of said detector elements fully laps said space field;

electronic means including key means alternately keying said transmitting elements for alternating transmission, means for sampling and storing the separate outputs of said detector elements in keyed synchronism with the keying of said transmitting elements, evaluating means connected to evaluate currently sampled values against stored values in alternation synchronized with said keyed alternation; and

threshold-operated alarm means connected to produce an alarm-signal output only upon concurrent evaluation of at least a predetermined difference in value for currently detected vs. stored signals in both of said keying intervals.

6. The system of claim 5, in which each of said subsystems comprises a plurality of transmitting elements, there being one transmitting element determining each intruder-response sector.

7. A security system comprising first and second detecting subsystems wherein each subsystem comprises at least one detector element and wherein the subsystem is mounted for directionally limited response in a plurality of angularly spaced intruder-response sectors spaced by at least substantially three times the angular width of a single intruder-response sector, and the mounting of said subsystems being such that the intruder-response sectors of one subsystem are in substantially uniformly spaced interlace with the intruder-response sectors of the other system in their mutual coverage of said field;

at least two laterally spaced transmitting elements for transmitting infrared radiation within the response wavelength region of said detector elements, said transmitting elements being in spaced adjacency to said detecting subsystems and such that each of said transmitting elements can irradiate said space field;

electronic means including key means keying said transmitting elements for alternating transmission, means for sampling and storing the separate outputs of said detector elements in keyed synchronism with the keying of said transmitting elements.

8. The system of claim 7, in which each of said subsystems comprises a plurality of detector elements, there being one detector element determining each intruder-response sector.

9. The system of claim 7, and including threshold-operated alarm means connected to produce an alarm-signal output only upon concurrent evaluation of at least a predetermined difference in value for currently detected vs. stored signals in both of said keying intervals.