EP0772171B1 - Passive intrusion detector and its use - Google Patents

Passive intrusion detector and its use Download PDF

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Publication number
EP0772171B1
EP0772171B1 EP19960116924 EP96116924A EP0772171B1 EP 0772171 B1 EP0772171 B1 EP 0772171B1 EP 19960116924 EP19960116924 EP 19960116924 EP 96116924 A EP96116924 A EP 96116924A EP 0772171 B1 EP0772171 B1 EP 0772171B1
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EP
European Patent Office
Prior art keywords
detector
light source
radiation
sabotage
passive infrared
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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EP19960116924
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German (de)
French (fr)
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EP0772171A1 (en
Inventor
Dieter Wieser
Kurt Albert Dr. Müller
Martin Dr. Allemann
Michael Thomas Dr. Gale
Thomas Hessler
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Siemens Building Technologies AG
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Siemens Building Technologies AG
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Priority to EP19960116924 priority Critical patent/EP0772171B1/en
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
    • G08B29/02—Monitoring continuously signalling or alarm systems
    • G08B29/04—Monitoring of the detection circuits
    • G08B29/046—Monitoring of the detection circuits prevention of tampering with detection circuits

Definitions

  • the following invention relates to a passive infrared intrusion detector, in particular with an anti-sabotage device and its use.
  • Such passive infrared intrusion detectors are used to monitor rooms such as Example in museums, bank buildings or industrial areas by using the body radiation from Detect unauthorized persons in the wavelength range from approx. 6 to 15 ⁇ m. They consist in essentially from a housing with a transparent in the infrared wavelength range Entry window, focusing optics, one or more infrared sensors and one electrical signal evaluation and alarm output circuit.
  • the entry window usually exists Made of infrared-transmissive polypropylene or polyethylene.
  • An unauthorized person enters the the area monitored by the detector passes its infrared body radiation through the Entry window into the interior of the intrusion detector and is focused on by the optics Infrared sensors steered.
  • the infrared sensors send a signal to the evaluation circuit which amplifies the signal and compares it with a predetermined threshold. Will the an alarm signal is emitted.
  • a burglar detector of this type is described, for example, in EP 0 499 177.
  • the one mentioned Sabotage security device has an active radiation source on one Side of the entrance window, the radiation of which is transmitted through the entrance window and from a detector is received on the other side of the window. That from the detector The electrical signal emitted is then evaluated by a circuit.
  • the radiation serves to measure the optical transmission of the entrance window as well as the immediate space monitor the presence of objects in front of the entrance window.
  • the properties of this radiation are chosen so that they ensure the normal function of the intrusion detector, the detection of infrared body radiation, does not interfere. Now the intrusion detector is through Covering or spraying sabotaged by a spray causes this to increase or decrease Reduction of radiation received by the detector.
  • the light source is typically formed by an LED that emits in the near infrared. On Spray that is used for sabotage is partially permeable in the near infrared, so that the signal change in the event of sabotage is only small and the fault message is not is clear.
  • Another intrusion detector of this type is described in EP 0 481 934 A.
  • EP 0 189 536 a similar intrusion detector is described in EP 0 189 536, in which for the Light source uses a resistor that simulates the heat radiation from people.
  • this solution has the disadvantage that the energy consumption of a resistor for this Purpose is relatively high.
  • a passive infrared intrusion detector create, which has a facility for sabotage security, the sabotage acts like that Spraying of the entrance window is detected by an infrared-opaque spray and signaled.
  • the device is said to have the disadvantages of the above-mentioned prior art avoid by changing the signal to monitor the entrance window large and the sabotage message is therefore clear.
  • the task is accomplished by a passive infrared intrusion detector with one device Sabotage security solved, which is an active light source in the near infrared and one of her associated detector and a diffraction-optical grating structure, which on the Outside of the entrance window is integrated and light emitted by the light source the detector that belongs to it.
  • the light source and the detector is arranged so that one component outside the entrance window and the others are within the entry window.
  • the light source is located and the detector both within the entry window of the infrared intrusion detector.
  • the Sabotage security device monitors the entrance window for changes such as Example spraying by spray or other contaminants.
  • the light from the light source is directed at the entrance window and monitors the condition of the surface of the Entry window by part of it from the diffraction-optical grating structure on the Entry window in the first or a higher diffraction order focused on the detector becomes.
  • the light source and detector are both located within the entry window are a diffraction order in reflection; in the case where they're inside or outside the entrance window, it is a diffraction order in Transmission.
  • the detector sends an electrical signal to one Evaluation circuit from the state of the entrance window according to this electrical signal indicates. In the normal state, the entrance window is intact and the lattice structure is focused some of the light on the detector.
  • the Lattice structure coated on the entrance window with the adhesive In the event of sabotage by spraying the Entry window with a spray, such as an adhesive spray, the Lattice structure coated on the entrance window with the adhesive. The lattice structure is changed by filling them in and the surface of the entrance window equal to that of one diffuse spreader. The focusing effect of the diffraction-optical grating structure becomes destroyed, and the light radiation received by the detector is greatly reduced. If the signal from the detector to the evaluation circuit falls below one predetermined threshold, it signals a sabotage alarm.
  • a spray such as an adhesive spray
  • the diffraction grating according to the invention on the entrance window brings the Sabotage monitoring has the advantage that the monitoring signal due to the focusing effect of the grating is enlarged and thus the signal change in the event of sabotage is also large. The sabotage is determined more clearly.
  • An additional advantage is the arrangement of the light source and detector on the Inside of the entrance window, making their assembly easier.
  • the two elements integrated on the circuit board, which the evaluation and alarm circuit of the Intrusion detector contains.
  • This allows simple and inexpensive installation, such as Example the use of elements as a surface mount device (SMD) or elements in which light source and detector and associated electrical driver or Amplifier circuits are integrated in one element
  • Fig. 1 shows an exterior view of the passive infrared intrusion detector in perspective with the Diffractive optical element integrated in its entrance window.
  • 2a), 2b), 2c) and 2d) show examples of the profile of the integrated in the entry window diffraction-optical grating structure.
  • Fig. 3 shows the passive infrared intrusion detector in the vertical and to the entrance window vertical cross section with a first arrangement of the device for sabotage security.
  • FIG. 4 shows the passive infrared intrusion detector in the same cross section as in FIG. 3 a second arrangement of the anti-sabotage device.
  • Fig. 5 shows the passive infrared intrusion detector in horizontal cross section, in which the Light source outside and the detector are arranged inside the entrance window.
  • FIG. 1 shows a passive infrared intrusion detector 1, the housing 2 of which has an entry window 3 has, which faces the room to be monitored. While the housing 2 for any radiation is opaque, infrared radiation occurs in the wavelength range of 6-15 ⁇ m through the entrance window 3 into the interior of the housing.
  • the entrance window 3 points to his Outside a diffraction-optical grating structure 4, which covers the entire surface of the Entry window 3 fills.
  • the lattice structure 4 consisting of fine grooves, the one form a phase-modulating relief structure, focuses part of the light emitted by the Light source falls on it, on a detector inside the housing 2.
  • the diffractive optical element consists of an elliptical Lattice structure 4, in which the local lattice constant, the distance between the individual Grooves, with increasing radius becomes smaller, which is the diffraction-optical Lattice structure that gives a focusing effect.
  • the lattice structure 4 can also consist of a circular or rectilinear lattice structure, whose lattice constant in turn increases with increasing distance from the center of the Grid structure becomes smaller in each case. The latter rectilinear lattice structure has the effect of a cylindrical focusing element.
  • the lattice structure is also designed so that it has the function of focusing the Light of the light source performs the detection of infrared radiation from the monitoring room but not affected.
  • a light source is used for this purpose Wavelength is different from that of infrared radiation.
  • a light source is suitable for this in the visible or near infrared.
  • the grating structure is for the wavelength of the light The light source determines and has an insignificant influence on the radiation in the infrared range.
  • Figures 2a), 2b), 2c) and 2d) schematically show examples of a profile of the diffractive optics Lattice structure. Since this is a phase-modulating lattice structure, the depth t of the grooves of the lattice structure 4 is dimensioned such that that through the lattice structure caused optical phase difference is 2 ⁇ or an integer multiple of 2 ⁇ . This is done, for example, in the case of the arrangement of the light source and the detector inside the entrance window and the use of the lattice structure in reflection takes into account that the diffraction occurs in the material of the entrance window and therefore the Refractive index of the window material is taken into account when determining the depth t.
  • the Depth t results from this for normal angles of incidence equal to ⁇ / 2n, where ⁇ is the wavelength of the Light and n is the refractive index of the window material.
  • ⁇ is the wavelength of the Light
  • n is the refractive index of the window material.
  • the depth t is 266 nm.
  • the beam path of the infrared radiation from the room to be monitored is determined by does not affect a grating of such a depth, since its shortest wavelength is 6 ⁇ m and for this wavelength the depth of 266 nm is a phase difference of much corresponds to less than 2 ⁇ .
  • the profile of the lattice structure 4 is either one Sine function as in Fig. 2a), a rectangular function as in Fig. 2b) or a triangular one Sawtooth function as shown in Fig. 2c).
  • a grid with a profile with a so-called "blaze” as in Fig. 2c) is also known under blazed grating.
  • Lattice structures with these profiles differ in that they have different diffraction efficiencies and on different ways are made.
  • Fig. 2d) does not show the profile of a grid linear blaze. It is similar to the profile of 2c), but has a slight one Surface curvature.
  • the local lattice constant should be significantly smaller than the shortest Wavelength of the infrared radiation, which is detected by the intrusion detector.
  • a small local grating constant relative to the wavelength of the infrared radiation causes the Grid structure the beam path of the infrared radiation from the room to be monitored the infrared sensors do not interfere and their detection does not affect the radiation of the
  • light source for monitoring the entrance window is focused on the detector.
  • the local lattice constant the manufacturability of these dimensions is also important and to consider the achievable diffraction efficiency.
  • Execution of the lattice structure 4 is the smallest local lattice constant 5 ⁇ m. This is greater than the recommended lattice constant, but the structure can lead to dimensional accuracy be produced, which causes a high diffraction efficiency.
  • the vertical cross section of the passive infrared intrusion detector 1 in FIG. 3 shows one in Focusing optics 5 arranged inside the intrusion detector in the form of a concave mirror which the body radiation falling from the room to be monitored onto the infrared sensors 6 focused. These are sensitive to radiation in the wavelength range from 6 to 15 ⁇ m. If they detect body radiation from this area, they send a signal to the evaluation and Alarm delivery circuit on the circuit board 7.
  • a light source 8 and its associated detector 9 arranged.
  • the light source 8 is a light emitting diode, the light in the near infrared wavelength range.
  • the for Detector 9 belonging to light source 8 has a sensitivity in the wavelength range of Light source 8. This is preferably a photodetector such as a silicon photodiode.
  • the beam path of the light source 8 for monitoring the entrance window 3 emitted light is marked with broken lines.
  • the light falls on that Entry window 3 and is focused by the grating structure 4 on the detector 9. It deals the first or a higher diffraction order in reflection. Will that Entry window 3 and the lattice structure 4 covered by adhesive spray, the lattice structure defaced and the light is no longer focused but diffusely scattered. As a result, the falls light intensity received by the detector 9. Falls below the signal it emits below a given threshold, a sabotage alarm is given.
  • the diffraction efficiency is optical diffraction Lattice structure also for a blazed lattice less than 100%, and it will only be part of that the grating structure 4 striking radiation as a monitoring signal of the entrance window on the Detector 9 focused. Another part of the radiation passes through the entrance window 3 in the free space and does nothing to monitor the entrance window. A final part the radiation is scattered at the entrance window 3.
  • the scattered radiation is from the housing 2 absorbs or arrives after multiple reflections inside the housing 2 and on the Focusing optics 5 on the detector 9.
  • the radiation caused by scattering and Multiple reflections reached the detector 9 forms the monitoring signal of the Entry window an underground signal that does not change in the event of sabotage by spray changed.
  • the focusing optics 5 can be designed to reduce this background signal that near-infrared radiation is absorbed by it, but body radiation by it is reflected.
  • a black lens for example, is suitable for such focusing optics light absorbing material covered with a layer of indium tin oxide (also under the English abbreviation known ITO) is coated.
  • the layer of indium tin oxide reflects radiation in the area of body radiation, but leaves the visible and near infrared Radiation so that it falls onto the black material and is absorbed by it.
  • the light source 8 is on the circuit board 7 next to the detector 9 and arranged in the plane parallel to that of the entry window.
  • the assembly on the Printed circuit board 7 is somewhat easier in this arrangement.
  • FIG. 1 Another embodiment of the infrared intrusion detector is shown in FIG.
  • the light source 8 and the associated detector 9 are inside the entrance window 3 and next to one another in an opening 10 in the focusing optics 5 opposite the entrance window 3.
  • This Arrangement opposite the entrance window 3 and the lattice structure 4 allows compared to Arrangement in Fig. 2 a smaller angle of incidence of the light of the light source 8 on the Lattice structure 4. The smaller angle of incidence enables a higher diffraction efficiency.
  • the light source 8 and the detector 9 can be close to each other an integrated element can be used here, the light source 8, the detector 9, the Control circuit for the light source 8 and the amplifier circuit for the detector 9 in contains an element. Although in this arrangement this element is not on the circuit board 7 comes to rest, the use of an integrated element of this type offers advantages assembly.
  • Figure 5 shows a further embodiment of the invention, in which the light source 8 outside the Entry window 3 with lattice structure 4 and on the side of the housing 2 and the detector 9 inside the intrusion detector 1 is arranged.
  • Light from the light source 8 onto the lattice structure 4 of the entrance window 3 falls in the first or a higher diffraction order in Transmission focused on the detector 9.
  • the lattice structure 4 is destroyed, and by the radiation from the light source, which normally falls on the detector 9, only a small fraction is received, and that Monitoring signal is significantly reduced.
  • the above-mentioned lattice structure is produced by an injection-stamping process, in which the entrance window is first injected and then the lattice structure 4 at an elevated temperature of the material is embossed into the window.
  • a master stamp is issued, which is the Contains lattice structure used.
  • Such a master stamp is made of metal, for example.
  • the structure is, for example, in a first step in a photoresist holographic method, a laser writing process or electron beam lithography manufactured.
  • the holographic method is used in particular if that Grid profile should have a sine function.
  • the laser writing method on the other hand, is suitable for the production of lattice profiles with a rectangular or sawtooth function. Consists the desired structure in the photoresist becomes one of them in a galvanic process negative copy made in metal such as nickel which is used as a master stamp for the Embossing the entrance window serves.

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  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Burglar Alarm Systems (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Description

Die folgende Erfindung betrifft einen passiven Infrarot-Einbruchdetektor, insbesondere mit einer Einrichtung für Sabotagesicherheit, und dessen Verwendung.The following invention relates to a passive infrared intrusion detector, in particular with an anti-sabotage device and its use.

Solche passiven Infrarot-Einbruchdetektoren dienen zur Überwachung von Räumen, wie zum Beispiel in Museen, Bankgebäuden oder Industriearealen, indem sie die Körperstrahlung von unbefugten Personen im Wellenlängenbereich von ca. 6 bis 15 µm detektieren. Sie bestehen im wesentlichen aus einem Gehäuse mit einem im infraroten Wellenlängenbereich durchlässigen Eintrittsfenster, einer Fokussieroptik, einem oder mehreren Infrarot-Sensoren sowie einer elektrischen Signalauswerte- und Alarmabgabeschaltung. Das Eintrittsfenster besteht zumeist aus infrarot-durchlässigem Polypropylen oder Polyethylen. Tritt eine unbefugte Person in den vom Detektor überwachten Bereich, gelangt ihre infrarote Körperstrahlung durch das Eintrittsfenster in das Innere des Einbruchdetektors und wird von der Fokussieroptik auf die Infrarot-Sensoren gelenkt. Die Infrarot-Sensoren geben ein Signal an die Auswerteschaltung ab, die das Signal verstärkt und mit einer vorgegebenen Schwelle vergleicht. Wird die vorgegebene Schwelle überstiegen, so wird ein Alarmsignal abgegeben.Such passive infrared intrusion detectors are used to monitor rooms such as Example in museums, bank buildings or industrial areas by using the body radiation from Detect unauthorized persons in the wavelength range from approx. 6 to 15 µm. They consist in essentially from a housing with a transparent in the infrared wavelength range Entry window, focusing optics, one or more infrared sensors and one electrical signal evaluation and alarm output circuit. The entry window usually exists Made of infrared-transmissive polypropylene or polyethylene. An unauthorized person enters the the area monitored by the detector passes its infrared body radiation through the Entry window into the interior of the intrusion detector and is focused on by the optics Infrared sensors steered. The infrared sensors send a signal to the evaluation circuit which amplifies the signal and compares it with a predetermined threshold. Will the an alarm signal is emitted.

In neuester Zeit ist es vermehrt vorgekommen, dass unbefugte Personen die passiven Infrarot-Einbruchdetektoren manipulieren, sodass diese funktionsuntüchtig werden. Oft werden dabei die Infrarot-Einbruchdetektoren so sabotiert, dass keine Infrarotstrahlung durch ihr Eintrittsfenster mehr gelangen kann und sie in diesem Strahlungsbereich erblinden. Unbefugte Personen werden dann nicht mehr detektiert und können sich in dem betreffenden Raum frei und unbemerkt bewegen. Eine Sabotage wird zumeist während der Unscharfstellung des Einbruchdetektors verübt, also während der Zeit, in der er auf einen Stand-by-Modus geschaltet ist und sich Personen in dem Raum aufhalten dürfen. Eine bekannte Sabotagemethode ist die Abdeckung des Einbruchdetektors mit einem Objekt wie zum Beispiel einem Karton oder Schirm. Diese Sabotage kann jedoch auch leicht von Wachpersonen bemerkt und behoben werden. Eine raffiniertere und von Wachpersonen schwer bemerkbare Sabotage hingegen ist die Besprühung des Eintrittsfensters mit einem Spray wie zum Beispiel einem Klebstoff- oder Haarspray. Diese Sprays sind fiir das Auge transparent, jedoch für die Strahlung im infraroten Bereich undurchlässig. Sie sind leicht erhältlich und auch sehr schnell auf das Eintrittsfenster gesprüht. Die letztere Sabotagemethode ist heute die meist angewandte. Um eine solche unerwünschte Sabotage automatisch durch den Einbruchdetektor selbst zu detektieren, sei es zum unmittelbaren Zeitpunkt der Sabotage während der Unscharfstellung oder erst bei der Scharfstellung des Detektors, sind neueste Detektoren mit einer Einrichtung zur Detektion von Sabotageakten, insbesondere zur Überwachung des Eintrittsfenster, ausgerüstet worden.In recent times, it has happened that unauthorized persons use the passive infrared intrusion detectors manipulate so that they become inoperable. Often there sabotaged the infrared intrusion detectors so that no infrared radiation through it Entry window can reach more and they go blind in this radiation area. unauthorized People are then no longer detected and can move freely in the room in question and move unnoticed. Sabotage is mostly during the disarming of the Burglar detector perpetrates, i.e. during the time it is in a standby mode is switched on and people are allowed to stay in the room. An acquaintance The sabotage method is to cover the intrusion detector with an object such as a box or umbrella. However, this sabotage can also be easily done by security guards noticed and fixed. A more refined and difficult to see by guards Sabotage, on the other hand, is spraying the entrance window with a spray such as an adhesive or hair spray. These sprays are transparent to the eye, but for the Radiation in the infrared range is opaque. They are easily available and also very fast sprayed on the entrance window. The latter method of sabotage is the most commonly used today. To prevent such unwanted sabotage automatically by the intrusion detector itself detect, be it at the immediate point of sabotage during disarming or only when the detector is in focus are the latest detectors with one device for the detection of acts of sabotage, in particular for monitoring the entrance window, been equipped.

Ein Einbruchdetektor dieser Art ist zum Beispiel in EP 0 499 177 beschrieben. Die erwähnte Einrichtung für Sabotagesicherheit verfügt über eine aktive Strahlungsquelle auf der einen Seite des Eintrittsfensters, deren Strahlung durch das Eintrittsfenster transmittiert und von einem Detektor auf der anderen Seite des Fensters empfangen wird. Das vom Detektor abgegebene elektrische Signal wird dann von einer Schaltung ausgewertet. Die Strahlung dient dazu, die optische Transmission des Eintrittsfensters zu messen sowie den unmittelbaren Raum vor dem Eintrittsfenster auf die Präsenz von Objekten zu überwachen. Die Eigenschaften dieser Strahlung sind jeweils so gewählt, dass sie die normale Funktion des Einbruchdetektors, der Detektion von infrarot-Körperstrahlung, nicht stört. Wird nun der Einbruchdetektor durch Abdeckung oder Besprühung durch einen Spray sabotiert, bewirkt dies einen Anstieg bzw. eine Reduktion der vom Detektor empfangenen Strahlung. Beträgt das vom Detektor resultierende Signal einen Wert ausserhalb eines vorgegebenen Bereichs, so wird ein Alarm signalisiert. Die Lichtquelle ist typischerweise durch eine LED ausgebildet, die im nahen Infrarot strahlt. Ein Spray, der zur Sabotage verwendet wird, ist aber im nahen Infrarot zum Teil durchlässig, sodass die Signaländerung im Fall einer Sabotage nur klein und die Störungsmeldung nicht eindeutig ist Ein weiterer Einbruchdetektor dieser Art ist in EP 0 481 934 A beschrieben. Ferner wird in EP 0 189 536 ein ähnlicher Einbruchdetektor beschrieben, bei dem für die Lichtquelle ein Widerstand verwendet wird, der die Wärmestrahlung von Personen simuliert. Diese Lösung hat aber den Nachteil, dass der Energieverbrauch eines Widerstands für diesen Zweck relativ hoch ist.A burglar detector of this type is described, for example, in EP 0 499 177. The one mentioned Sabotage security device has an active radiation source on one Side of the entrance window, the radiation of which is transmitted through the entrance window and from a detector is received on the other side of the window. That from the detector The electrical signal emitted is then evaluated by a circuit. The radiation serves to measure the optical transmission of the entrance window as well as the immediate space monitor the presence of objects in front of the entrance window. The properties of this radiation are chosen so that they ensure the normal function of the intrusion detector, the detection of infrared body radiation, does not interfere. Now the intrusion detector is through Covering or spraying sabotaged by a spray causes this to increase or decrease Reduction of radiation received by the detector. Is the result of the detector Signal a value outside a specified range, an alarm is signaled. The The light source is typically formed by an LED that emits in the near infrared. On Spray that is used for sabotage is partially permeable in the near infrared, so that the signal change in the event of sabotage is only small and the fault message is not is clear Another intrusion detector of this type is described in EP 0 481 934 A. Furthermore, a similar intrusion detector is described in EP 0 189 536, in which for the Light source uses a resistor that simulates the heat radiation from people. However, this solution has the disadvantage that the energy consumption of a resistor for this Purpose is relatively high.

Es ist die Aufgabe der folgenden Erfindung, die durch die Ansprüche definiert ist, einen passiven Infrarot-Einbruchdetektor zu schaffen, der über eine Einrichtung für Sabotagesicherheit verfügt, die Sabotageakte wie die Besprühung des Eintrittsfensters durch einen infrarot-undurchlässigen Spray detektiert und signalisiert. Die Einrichtung soll die Nachteile des obengenannten Standes der Technik vermeiden, indem die Änderung des Signals zur Überwachung des Eintrittsfensters gross und somit die Sabotagemeldung eindeutig ist.It is the object of the following invention defined by the claims, a passive infrared intrusion detector create, which has a facility for sabotage security, the sabotage acts like that Spraying of the entrance window is detected by an infrared-opaque spray and signaled. The device is said to have the disadvantages of the above-mentioned prior art avoid by changing the signal to monitor the entrance window large and the sabotage message is therefore clear.

Die Aufgabe wird durch einen passiven Infrarot-Einbruchdetektor mit einer Einrichtung fiir Sabotagesicherheit gelöst, die eine aktive Lichtquelle im nahen Infrarot und einen ihr dazugehörigen Detektor sowie eine beugungs-optische Gitterstruktur aufweist, die auf der Aussenseite des Eintrittsfensters integriert ist und von der Lichtquelle ausgesandtes Licht auf den ihr dazugehörigen Detektor fokussiert. In einer ersten Ausführung sind die Lichtquelle und der Detektor so angeordnet, dass das eine Bauteil ausserhalb des Eintrittsfensters und das andere innerhalb des Eintrittsfensters liegen. In einer zweiten Ausführung liegen die Lichtquelle und der Detektor beide innerhalb des Eintrittsfensters des Infrarot-Einbruchdetektors. Die Einrichtung für Sabotagesicherheit überwacht das Eintrittsfenster auf Veränderungen wie zum Beispiel Besprühung durch Spray oder andere Verunreinigungen. Das Licht der Lichtquelle ist auf das Eintrittsfenster gerichtet und überwacht den Zustand der Oberfläche des Eintrittsfensters, indem ein Teil davon von der beugungs-optischen Gitterstruktur auf dem Eintrittsfenster in der ersten oder einer höheren Beugungsordnung auf den Detektor fokussiert wird. In dem Fall, wo Lichtquelle und Detektor beide innerhalb des Eintrittsfenster angeordnet sind, handelt es sich um eine Beugungsordnung in Reflexion; in dem Fall, wo sie innerhalb bzw. ausserhalb des Eintrittsfensters liegen, handelt es sich um eine Beugungsordnung in Transmission. Beim Empfang dieses Lichts gibt der Detektor ein elektrisches Signal an eine Auswerteschaltung ab, die den Zustand des Eintrittsfensters gemäss dieses elektrischen Signals angibt. Im Normalzustand ist das Eintrittsfenster unversehrt, und die Gitterstruktur fokussiert einen Teil des Lichts auf den Detektor. Im Fall einer Sabotage durch Besprühung des Eintrittsfensters mit einem Spray, wie zum Beispiel einem Klebstoffspray, wird die Gitterstruktur auf dem Eintrittsfenster mit dem Klebstoff beschichtet. Die Gitterstruktur wird dabei verändert, indem sie ausgefüllt und die Oberfläche des Eintrittsfensters gleich der eines diffusen Streuers wird. Die fokussierende Wirkung der beugungs-optischen Gitterstruktur wird dabei zerstört, und die vom Detektor empfangene Lichtstrahlung wird stark vermindert. Unterschreitet das vom Detektor an die Auswerteschaltung abgegebene Signal eine vorgegebene Schwelle, wird von ihr ein Sabotagealarm signalisiert.The task is accomplished by a passive infrared intrusion detector with one device Sabotage security solved, which is an active light source in the near infrared and one of her associated detector and a diffraction-optical grating structure, which on the Outside of the entrance window is integrated and light emitted by the light source the detector that belongs to it. In a first embodiment, the light source and the detector is arranged so that one component outside the entrance window and the others are within the entry window. In a second embodiment, the light source is located and the detector both within the entry window of the infrared intrusion detector. The Sabotage security device monitors the entrance window for changes such as Example spraying by spray or other contaminants. The light from the light source is directed at the entrance window and monitors the condition of the surface of the Entry window by part of it from the diffraction-optical grating structure on the Entry window in the first or a higher diffraction order focused on the detector becomes. In the case where the light source and detector are both located within the entry window are a diffraction order in reflection; in the case where they're inside or outside the entrance window, it is a diffraction order in Transmission. When this light is received, the detector sends an electrical signal to one Evaluation circuit from the state of the entrance window according to this electrical signal indicates. In the normal state, the entrance window is intact and the lattice structure is focused some of the light on the detector. In the event of sabotage by spraying the Entry window with a spray, such as an adhesive spray, the Lattice structure coated on the entrance window with the adhesive. The lattice structure is changed by filling them in and the surface of the entrance window equal to that of one diffuse spreader. The focusing effect of the diffraction-optical grating structure becomes destroyed, and the light radiation received by the detector is greatly reduced. If the signal from the detector to the evaluation circuit falls below one predetermined threshold, it signals a sabotage alarm.

Das erfindungsgemässe Beugungsgitter auf dem Eintrittsfenster bringt der Sabotageüberwachung den Vorteil, dass das Überwachungssignal durch die Fokussierwirkung des Gitters vergrössert ist und somit auch die Signaländerung im Fall einer Sabotage gross ist. Die Ermittlung einer Sabotage erfolgt dadurch eindeutiger.The diffraction grating according to the invention on the entrance window brings the Sabotage monitoring has the advantage that the monitoring signal due to the focusing effect of the grating is enlarged and thus the signal change in the event of sabotage is also large. The sabotage is determined more clearly.

Ein zusätzlicher Vorteil erbringt die Anordnung von Lichtquelle und Detektor auf der Innenseite des Eintrittsfenster, indem ihre Montage erleichtert ist. Vorzugsweise sind die beiden Elemente auf der Leiterplatte integriert, welche die Auswerte- und Alarmschaltung des Einbruchdetektors enthält. Dies erlaubt eine einfache und kostengünstige Montage, wie zum Beispiel die Verwendung von Elementen als Surface-Mount-Device (SMD) oder Elementen, in denen Lichtquelle und Detektor sowie dazugehörige elektrische Treiber- bzw. Verstärkerschaltungen in einem Element integriert sindAn additional advantage is the arrangement of the light source and detector on the Inside of the entrance window, making their assembly easier. Preferably, the two elements integrated on the circuit board, which the evaluation and alarm circuit of the Intrusion detector contains. This allows simple and inexpensive installation, such as Example the use of elements as a surface mount device (SMD) or elements in which light source and detector and associated electrical driver or Amplifier circuits are integrated in one element

Die Erfindung und verschiedene Ausführungen der Erfindung sind im folgenden anhand der Figuren 1 bis 5 näher erläutert.The invention and various embodiments of the invention are described below with reference to the Figures 1 to 5 explained in more detail.

Fig. 1 zeigt eine Aussenansicht des passiven Infrarot-Einbruchdetektors in Perspektive mit dem beugungs-optischen Element integriert in seinem Eintrittsfenster. Fig. 1 shows an exterior view of the passive infrared intrusion detector in perspective with the Diffractive optical element integrated in its entrance window.

Fig. 2a), 2b), 2c) und 2d) zeigen Beispiele des Profils der im Eintrittsfenster integrierten beugungs-optischen Gitterstruktur.2a), 2b), 2c) and 2d) show examples of the profile of the integrated in the entry window diffraction-optical grating structure.

Fig. 3 zeigt den passiven Infrarot-Einbruchdetektor im vertikalen und zum Eintrittsfenster senkrechten Querschnitt mit einer ersten Anordnung der Einrichtung für Sabotagesicherheit.Fig. 3 shows the passive infrared intrusion detector in the vertical and to the entrance window vertical cross section with a first arrangement of the device for sabotage security.

Fig. 4 zeigt den passiven Infrarot-Einbruchdetektor im gleichen Querschnitt wie in Fig. 3 mit einer zweiten Anordnung der Einrichtung fiir Sabotagesicherheit.FIG. 4 shows the passive infrared intrusion detector in the same cross section as in FIG. 3 a second arrangement of the anti-sabotage device.

Fig. 5 zeigt den passiven Infrarot-Einbruchdetektor im horizontalen Querschnitt, bei dem die Lichtquelle ausserhalb und der Detektor innerhalb des Eintrittsfensters angeordnet sind.Fig. 5 shows the passive infrared intrusion detector in horizontal cross section, in which the Light source outside and the detector are arranged inside the entrance window.

Fig. 1 zeigt einen passiven Infrarot-Einbruchdetektor 1, dessen Gehäuse 2 ein Eintrittsfenster 3 aufweist, das dem zu überwachenden Raum zugewandt ist. Während das Gehäuse 2 für jegliche Strahlung undurchlässig ist, tritt Infrarot-Strahlung im Wellenlängenbereich von 6-15 µ m durch das Eintrittsfenster 3 in das Gehäuseinnere. Das Eintrittsfenster 3 weist auf seiner Aussenseite eine beugungs-optische Gitterstruktur 4 auf, welche die gesamte Fläche des Eintrittsfensters 3 ausfüllt. Die Gitterstruktur 4, bestehend aus feinen Rillen, die eine phasenmodulierende Reliefstruktur bilden, fokussiert einen Teil des Lichts, das von der Lichtquelle auf sie fällt, auf einen Detektor im Inneren des Gehäuses 2. (Die Distanz zwischen den einzelnen Rillen liegt im Mikrometerbereich; daher sind in der Figur nur einige der Rillen der Gitterstruktur angedeutet.) Sie besteht aus demselben Material wie das des Eintrittsfensters 3, zumeist Polyethylen oder Polypropylen, und wird bei der Herstellung des Eintrittsfensters durch Spritzprägung auf seine Oberfläche gebracht.1 shows a passive infrared intrusion detector 1, the housing 2 of which has an entry window 3 has, which faces the room to be monitored. While the housing 2 for any radiation is opaque, infrared radiation occurs in the wavelength range of 6-15 µ m through the entrance window 3 into the interior of the housing. The entrance window 3 points to his Outside a diffraction-optical grating structure 4, which covers the entire surface of the Entry window 3 fills. The lattice structure 4, consisting of fine grooves, the one form a phase-modulating relief structure, focuses part of the light emitted by the Light source falls on it, on a detector inside the housing 2. (The distance between the individual grooves are in the micrometer range; therefore, only some of the grooves are in the figure of the lattice structure.) It is made of the same material as that of the entrance window 3, mostly polyethylene or polypropylene, and is used in the manufacture of the entrance window brought onto its surface by spray embossing.

Wie in der Figur angedeutet, besteht das beugungs-optische Element aus einer elliptischen Gitterstruktur 4, bei welcher die lokale Gitterkonstante, der Abstand zwischen den einzelnen Rillen, mit grösser werdendem Radius jeweils kleiner wird, was der beugungs-optischen Gitterstruktur die fokussierende Wirkung verleiht. Anstelle einer elliptischen Gitterstruktur, kann die Gitterstruktur 4 auch aus einer kreisrunden oder geradlinigen Gitterstruktur bestehen, deren Gitterkonstante wiederum mit grösser werdender Distanz von der Mitte der Gitterstruktur jeweils kleiner wird. Letztere geradlinige Gitterstruktur hat die Wirkung eines zylindrischen Fokussierelementes.As indicated in the figure, the diffractive optical element consists of an elliptical Lattice structure 4, in which the local lattice constant, the distance between the individual Grooves, with increasing radius becomes smaller, which is the diffraction-optical Lattice structure that gives a focusing effect. Instead of an elliptical lattice structure, the lattice structure 4 can also consist of a circular or rectilinear lattice structure, whose lattice constant in turn increases with increasing distance from the center of the Grid structure becomes smaller in each case. The latter rectilinear lattice structure has the effect of a cylindrical focusing element.

Die Gitterstruktur ist weiterhin so ausgebildet, dass sie die Funktion der Fokussierung des Lichts der Lichtquelle durchführt, die Detektion der Infrarot-Strahlung aus dem zu überwachenden Raum aber nicht beeinträchtigt. Hierzu wird eine Lichtquelle eingesetzt, deren Wellenlänge verschieden ist von der der Infrarot-Strahlung. Hierzu eignet sich eine Lichtquelle im sichtbaren oder nahen Infrarot. Die Gitterstruktur ist fiir die Wellenlänge des Lichts dieser Lichtquelle bestimmt und hat auf die Strahlung im infraroten Bereich unwesentlichen Einfluss.The lattice structure is also designed so that it has the function of focusing the Light of the light source performs the detection of infrared radiation from the monitoring room but not affected. A light source is used for this purpose Wavelength is different from that of infrared radiation. A light source is suitable for this in the visible or near infrared. The grating structure is for the wavelength of the light The light source determines and has an insignificant influence on the radiation in the infrared range.

Die Figuren 2a), 2b), 2c) und 2d) zeigen schematisch Beispiele eines Profils der beugungs-optischen Gitterstruktur. Da es sich hier um eine phasenmodulierende Gitterstruktur handelt, ist die Tiefe t der Rillen der Gitterstruktur 4 so dimensioniert, dass der durch die Gitterstruktur bewirkte optische Phasenunterschied 2π oder ein ganzzahliges Vielfaches von 2π beträgt. Hierzu wird beispielsweise für den Fall der Anordnung der Lichtquelle und des Detektors innerhalb des Eintrittsfensters und der Verwendung der Gitterstruktur in Reflexion berücksichtigt, dass die Beugung im Material des Eintrittsfensters sich ereignet und deshalb der Brechungsindex des Fenstermaterials bei der Bestimmung der Tiefe t miteinbezogen wird. Die Tiefe t ergibt sich hieraus für normale Einfallswinkel gleich λ/2n, wobei λ die Wellenlänge des Lichts und n der Brechungsindex des Fenstermaterials ist. Wird zum Beispiel als Lichtquelle eine Leuchtdiode verwendet, die Licht bei einer Wellenlänge von 800 nm ausstrahlt und n gleich 1.5 ist, beträgt die Tiefe t 266 nm. Bei grösseren Einfallswinkeln ist die Tiefe etwas kleiner. Der Strahlengang der Infrarot-Strahlung aus dem zu überwachenden Raum wird von einem Gitter einer solchen Tiefe nicht beeinträchtigt, da ihre kürzeste Wellenlänge 6 µm beträgt und für diese Wellenlänge die Tiefe von 266 nm einem Phasenunterschied von viel weniger als 2π entspricht. Das Profil der Gitterstruktur 4 ist hier entweder das einer Sinusfunktion wie in Fig. 2a), einer Rechteckfunktion wie in Fig. 2b) oder einer dreieckigen Sägezahnfunktion wie in Fig. 2c) gezeigt. Ein Gitter mit einem Profil mit sogenanntem "blaze" wie in Fig. 2c) ist auch unter geblaztem Gitter bekannt. Gitterstrukturen mit diesen Profilen unterscheiden sich, indem sie verschiedene Beugungseffizienzen aufweisen und auf verschiedene Weisen hergestellt werden. Fig. 2d) zeigt das Profil eines Gitters mit nicht linearem blaze. Sie ist dem Profil von 2c) ähnlich, besitzt aber eine leichte Oberflächenkrümmung.Figures 2a), 2b), 2c) and 2d) schematically show examples of a profile of the diffractive optics Lattice structure. Since this is a phase-modulating lattice structure, the depth t of the grooves of the lattice structure 4 is dimensioned such that that through the lattice structure caused optical phase difference is 2π or an integer multiple of 2π. This is done, for example, in the case of the arrangement of the light source and the detector inside the entrance window and the use of the lattice structure in reflection takes into account that the diffraction occurs in the material of the entrance window and therefore the Refractive index of the window material is taken into account when determining the depth t. The Depth t results from this for normal angles of incidence equal to λ / 2n, where λ is the wavelength of the Light and n is the refractive index of the window material. For example, as a light source uses a light emitting diode that emits light at a wavelength of 800 nm and n is 1.5, the depth t is 266 nm. At larger angles of incidence, the depth is somewhat smaller. The beam path of the infrared radiation from the room to be monitored is determined by does not affect a grating of such a depth, since its shortest wavelength is 6 µm and for this wavelength the depth of 266 nm is a phase difference of much corresponds to less than 2π. The profile of the lattice structure 4 is either one Sine function as in Fig. 2a), a rectangular function as in Fig. 2b) or a triangular one Sawtooth function as shown in Fig. 2c). A grid with a profile with a so-called "blaze" as in Fig. 2c) is also known under blazed grating. Lattice structures with these profiles differ in that they have different diffraction efficiencies and on different ways are made. Fig. 2d) does not show the profile of a grid linear blaze. It is similar to the profile of 2c), but has a slight one Surface curvature.

Die lokale Gitterkonstante sollte nach Theorie wesentlich kleiner sein als die kürzeste Wellenlänge der Infrarot-Strahlung, die durch den Einbruchdetektor detektiert wird. Eine relativ zur Wellenlänge der infraroten Strahlung kleine lokale Gitterkonstante bewirkt, dass die Gitterstruktur den Strahlengang der Infrarot-Strahlung aus dem zu überwachenden Raum auf die Infrarot-Sensoren nicht stört und ihre Detektion nicht beeinträchtigt, die Strahlung der Lichtquelle zur Überwachung des Eintrittsfensters jedoch auf den Detektor fokussiert wird. Bei der Wahl der lokalen Gitterkonstante ist aber auch die Herstellbarkeit dieser Dimensionen und die damit verbundene erreichbare Beugungseffizienz in Betracht zu ziehen. In dieser Ausführung der Gitterstruktur 4 beträgt die kleinste lokale Gitterkonstante 5 µm. Diese ist grösser als die empfohlene Gitterkonstante, die Struktur kann aber zu einer Formgenauigkeit hergestellt werden, die eine hohe Beugungseffizienz bewirkt. According to the theory, the local lattice constant should be significantly smaller than the shortest Wavelength of the infrared radiation, which is detected by the intrusion detector. A small local grating constant relative to the wavelength of the infrared radiation causes the Grid structure the beam path of the infrared radiation from the room to be monitored the infrared sensors do not interfere and their detection does not affect the radiation of the However, light source for monitoring the entrance window is focused on the detector. When choosing the local lattice constant, the manufacturability of these dimensions is also important and to consider the achievable diffraction efficiency. In this Execution of the lattice structure 4 is the smallest local lattice constant 5 µm. This is greater than the recommended lattice constant, but the structure can lead to dimensional accuracy be produced, which causes a high diffraction efficiency.

Der vertikale Querschnitt des passiven Infrarot-Einbruchdetektors 1 in Fig. 3 zeigt eine im Innern des Einbruchdetektors angeordnete Fokussieroptik 5 in Form eines Hohlspiegels, der die aus dem zu überwachenden Raum hereinfallende Körperstrahlung auf die Infrarot-Sensoren 6 fokussiert. Diese sind auf Strahlung im Wellenlängenbereich von 6 bis 15 µm empfindlich. Detektieren sie Körperstrahlung aus diesem Bereich, geben sie ein Signal an die Auswerte- und Alarmabgabeschaltung auf der Leiterplatte 7 ab. Zur Überwachung des Eintrittsfensters 3 auf Sabotageakte sind auf der Leiterplatte 7 eine Lichtquelle 8 und ein ihr dazugehöriger Detektor 9 angeordnet. Vorzugsweise ist die Lichtquelle 8 eine Leuchtdiode, die Licht im nahen infraroten Wellenlängenbereich abgibt. Sodass das von ihr abgegebene Licht die Detektion von Körperstrahlung durch die Infrarot-Sensoren nicht stört, wird sie gepulst betrieben und die Auswerteschaltung mit einem entsprechenden elektrischen Filter ausgerüstet. Der zur Lichtquelle 8 gehörige Detektor 9 besitzt eine Empfindlichkeit im Wellenlängenbereich der Lichtquelle 8. Vorzugsweise ist dieser ein Photodetektor wie zum Beispiel eine Silizium-Photodiode.The vertical cross section of the passive infrared intrusion detector 1 in FIG. 3 shows one in Focusing optics 5 arranged inside the intrusion detector in the form of a concave mirror which the body radiation falling from the room to be monitored onto the infrared sensors 6 focused. These are sensitive to radiation in the wavelength range from 6 to 15 µm. If they detect body radiation from this area, they send a signal to the evaluation and Alarm delivery circuit on the circuit board 7. To monitor the entry window 3 on Sabotage acts on the circuit board 7 are a light source 8 and its associated detector 9 arranged. Preferably, the light source 8 is a light emitting diode, the light in the near infrared wavelength range. So that the light it emits detects Does not interfere with body radiation from the infrared sensors, it is operated in pulsed mode and that Evaluation circuit equipped with an appropriate electrical filter. The for Detector 9 belonging to light source 8 has a sensitivity in the wavelength range of Light source 8. This is preferably a photodetector such as a silicon photodiode.

Der Strahlengang des von der Lichtquelle 8 zur Überwachung des Eintrittsfensters 3 ausgesandten Lichts ist mit gebrochenen Linien gekennzeichnet. Das Licht fällt auf das Eintrittsfenster 3 und wird durch die Gitterstruktur 4 auf den Detektor 9 fokussiert. Es handelt sich hierbei um die erste oder eine höhere Beugungsordnung in Reflexion. Wird das Eintrittsfenster 3 und die Gitterstruktur 4 durch Klebstoffspray bedeckt, wird die Gitterstruktur verunstaltet und das Licht nicht mehr fokussiert sondern diffus gestreut. Infolgedessen fällt die vom Detektor 9 empfangene Lichtintensität. Unterschreitet das von ihm abgegebene Signal unter eine gegebene Schwelle, wird ein Sabotagealarm abgegeben.The beam path of the light source 8 for monitoring the entrance window 3 emitted light is marked with broken lines. The light falls on that Entry window 3 and is focused by the grating structure 4 on the detector 9. It deals the first or a higher diffraction order in reflection. Will that Entry window 3 and the lattice structure 4 covered by adhesive spray, the lattice structure defaced and the light is no longer focused but diffusely scattered. As a result, the falls light intensity received by the detector 9. Falls below the signal it emits below a given threshold, a sabotage alarm is given.

In den meisten praktischen Fällen beträgt die Beugungseffizienz einer beugungs-optischen Gitterstruktur auch fiir ein geblaztes Gitter weniger als 100%, und es wird nur ein Teil der auf die Gitterstruktur 4 auffallende Strahlung als Überwachungssignal des Eintrittsfensters auf den Detektor 9 fokussiert. Ein weiterer Teil der Strahlung tritt durch das Eintrittsfenster 3 in den freien Raum hinaus und trägt nichts zur Überwachung des Eintrittsfensters bei. Ein letzter Teil der Strahlung wird am Eintrittsfenster 3 gestreut. Die gestreute Strahlung wird vom Gehäuse 2 absorbiert oder gelangt nach Mehrfachreflexionen im Innern des Gehäuses 2 und an der Fokussieroptik 5 auf den Detektor 9. Diejenige Strahlung, die durch Streuung und Mehrfachreflexionen den Detektor 9 erreicht, bildet zum Überwachungssignal des Eintrittsfensters ein Untergrundsignal, das sich im Fall einer Sabotage durch Spray nicht verändert. Zur Reduzierung dieses Untergrundsignals kann die Fokussieroptik 5 so ausgebildet werden, dass Strahlung im nahen Infrarot von ihr absorbiert, Körperstrahlung aber von ihr reflektiert wird. Für eine Fokussieroptik dieser Art eignet sich zum Beispiel ein schwarzes lichtabsorbierendes Material, das mit einer Schicht von Indium Zinnoxid (auch unter der englischen Abkürzung ITO bekannt) beschichtet ist. Die Schicht von Indium Zinnoxid reflektiert Strahlung im Bereich der Körperstrahlung, lässt aber die sichtbare und nahe infrarote Strahlung durch, sodass diese auf das schwarze Material fällt und von ihm absorbiert wird.In most practical cases, the diffraction efficiency is optical diffraction Lattice structure also for a blazed lattice less than 100%, and it will only be part of that the grating structure 4 striking radiation as a monitoring signal of the entrance window on the Detector 9 focused. Another part of the radiation passes through the entrance window 3 in the free space and does nothing to monitor the entrance window. A final part the radiation is scattered at the entrance window 3. The scattered radiation is from the housing 2 absorbs or arrives after multiple reflections inside the housing 2 and on the Focusing optics 5 on the detector 9. The radiation caused by scattering and Multiple reflections reached the detector 9 forms the monitoring signal of the Entry window an underground signal that does not change in the event of sabotage by spray changed. The focusing optics 5 can be designed to reduce this background signal that near-infrared radiation is absorbed by it, but body radiation by it is reflected. A black lens, for example, is suitable for such focusing optics light absorbing material covered with a layer of indium tin oxide (also under the English abbreviation known ITO) is coated. The layer of indium tin oxide reflects radiation in the area of body radiation, but leaves the visible and near infrared Radiation so that it falls onto the black material and is absorbed by it.

In einer alternativen Anordnung ist die Lichtquelle 8 auf der Leiterplatte 7 neben dem Detektor 9 und in der Ebene parallel zu der des Eintrittsfensters angeordnet. Die Montage auf der Leiterplatte 7 ergibt sich in dieser Anordnung etwas einfacher.In an alternative arrangement, the light source 8 is on the circuit board 7 next to the detector 9 and arranged in the plane parallel to that of the entry window. The assembly on the Printed circuit board 7 is somewhat easier in this arrangement.

In Fig. 4 ist eine weitere Ausführung des Infrarot-Einbruchdetektors gezeigt. Die Lichtquelle 8 und der dazugehörige Detektor 9 sind innerhalb des Eintrittsfensters 3 und nebeneinander in einer Öffnung 10 in der Fokussieroptik 5 gegenüber des Eintrittsfensters 3 angeordnet. Diese Anordnung gegenüber des Eintrittsfensters 3 und der Gitterstruktur 4 erlaubt im Vergleich zur Anordnung in Fig. 2 einen kleineren Einfallswinkel des Lichts der Lichtquelle 8 auf die Gitterstruktur 4. Der kleinere Einfallswinkel ermöglicht eine höhere Beugungseffizienz.Another embodiment of the infrared intrusion detector is shown in FIG. The light source 8 and the associated detector 9 are inside the entrance window 3 and next to one another in an opening 10 in the focusing optics 5 opposite the entrance window 3. This Arrangement opposite the entrance window 3 and the lattice structure 4 allows compared to Arrangement in Fig. 2 a smaller angle of incidence of the light of the light source 8 on the Lattice structure 4. The smaller angle of incidence enables a higher diffraction efficiency.

Da bei dieser Anordnung die Lichtquelle 8 und der Detektor 9 nahe beieinander liegen, kann hier ein integriertes Element eingesetzt werden, das die Lichtquelle 8, den Detektor 9, die Ansteurungsschaltung für die Lichtquelle 8 und die Verstärkerschaltung für den Detektor 9 in einem Element enthält. Obwohl in dieser Anordnung dieses Element nicht auf der Leiterplatte 7 zu liegen kommt, birgt die Verwendung eines integrierten Elementes dieser Art Vorteile in der Montage.Since in this arrangement the light source 8 and the detector 9 can be close to each other an integrated element can be used here, the light source 8, the detector 9, the Control circuit for the light source 8 and the amplifier circuit for the detector 9 in contains an element. Although in this arrangement this element is not on the circuit board 7 comes to rest, the use of an integrated element of this type offers advantages assembly.

Figur 5 zeigt eine weitere Ausführung der Erfindung, in der die Lichtquelle 8 ausserhalb des Eintrittsfensters 3 mit Gitterstruktur 4 und seitlich am Gehäuse 2 und der Detektor 9 im Innern des Einbruchdetektors 1 angeordnet ist. Licht, das von der Lichtquelle 8 auf die Gitterstruktur 4 des Eintrittsfensters 3 fällt, wird in der ersten oder einer höheren Beugungsordnung in Transmission auf den Detektor 9 fokussiert. Im Fall einer Besprayung des Eintrittsfenster 3, wird die Gitterstruktur 4 zerstört, und von der Strahlung der Lichtquelle, die normalerweise auf den Detektor 9 fällt, wird nur noch ein kleiner Anteil empfangen, und das Überwachungssignal wird bedeutend reduziert.Figure 5 shows a further embodiment of the invention, in which the light source 8 outside the Entry window 3 with lattice structure 4 and on the side of the housing 2 and the detector 9 inside the intrusion detector 1 is arranged. Light from the light source 8 onto the lattice structure 4 of the entrance window 3 falls in the first or a higher diffraction order in Transmission focused on the detector 9. In the case of spraying the entrance window 3, the lattice structure 4 is destroyed, and by the radiation from the light source, which normally falls on the detector 9, only a small fraction is received, and that Monitoring signal is significantly reduced.

Die obengenannte Gitterstruktur wird nach einem Spritz-Prägeverfahren hergestellt, bei dem das Eintrittsfenster zunächst gespritzt und die Gitterstruktur 4 danach bei erhöhter Temperatur des Materials in das Fenster geprägt wird. Für die Prägung wird ein Master-Stempel, der die Gitterstruktur enthält, verwendet. Ein solcher Master-Stempel besteht zum Beispiel aus Metall. Die Struktur wird in einem ersten Schritt in einem Photoresist zum Beispiel mittels holographischer Methode, eines Laser-Schreibverfahrens oder Elektronenstrahllithographie hergestellt. Die holographische Methode wird insbesondere dann angewendet, wenn das Gitterprofil eine Sinusfünktion aufweisen soll. Das Laser-Schreibverfahren andererseits eignet sich für die Herstellung von Gitterprofilen mit einer Rechteck- oder Sägezahnfünktion. Besteht die gewünschte Struktur im Photoresist, wird davon in einem galvanischen Prozess eine negative Kopie in Metall wie zum Beispiel Nickel hergestellt, die als Master-Stempel für die Prägung des Eintrittsfensters dient.The above-mentioned lattice structure is produced by an injection-stamping process, in which the entrance window is first injected and then the lattice structure 4 at an elevated temperature of the material is embossed into the window. For the embossing, a master stamp is issued, which is the Contains lattice structure used. Such a master stamp is made of metal, for example. The structure is, for example, in a first step in a photoresist holographic method, a laser writing process or electron beam lithography manufactured. The holographic method is used in particular if that Grid profile should have a sine function. The laser writing method, on the other hand, is suitable for the production of lattice profiles with a rectangular or sawtooth function. Consists the desired structure in the photoresist becomes one of them in a galvanic process negative copy made in metal such as nickel which is used as a master stamp for the Embossing the entrance window serves.

Claims (8)

  1. Passive infrared intrusion detector (1), consisting of a housing (2) with an entry window (3) which is transmissive for body radiation in the infrared wavelength range, focusing optics (5), infrared sensors (6) which are sensitive to body radiation, an evaluation and alarm-output circuit arranged on a printed circuit board (7), a device for sabotage security with an active light source (8) and a detector (9) associated therewith, characterised in that the device for sabotage security has an optical-diffraction grating structure (4) which is integrated on the outside of the entry window (3) and which focuses the light emitted by the light source (8) onto the detector (9).
  2. Passive infrared intrusion. detector (1) according to Patent Claim 1, characterised in that either the light source (8) is arranged inside and the detector (9) is arranged outside the entry window (3), or the light source (8) is arranged outside and the detector (9) is arranged inside the entry window (3).
  3. Passive infrared intrusion detector (1) according to Patent Claim 1, characterised in that the light source (8) and the detector (9) are both arranged inside the entry window (3).
  4. Passive infrared intrusion detector (1) according to Patent Claim 3, characterised in that the light source (8) and the detector (9) are arranged on the printed circuit board (7).
  5. Passive infrared intrusion detector (1) according to Patent Claim 3, characterised in that the light source (8) and the detector (9) are arranged in an opening (10) in the focusing optics (5).
  6. Passive infrared intrusion detector (1) according to one of Patent Claims 1 to 5, characterised in that the light source (8) emits light in the near infrared wave range of from 780 to 950 nm, and the detector (9) is sensitive to radiation in this wavelength range.
  7. Passive infrared intrusion detector (1) according to one of Patent Claims 1 to 5, characterised in that the light source (8) emits light in the visible wavelength range, and the detector (9) is sensitive to radiation in this wavelength range.
  8. Use of a passive infrared intrusion detector (1) according to one of Patent Claims 1 to 7 for warning of sabotage, characterised in that, in the event of sabotage to the passive infrared detector (1) by spraying the entry window (3) with an infrared-opaque spray, the light radiation focused onto the detector (9) is reduced and a sabotage alarm is traded by the alarm-output circuit.
EP19960116924 1995-11-03 1996-10-22 Passive intrusion detector and its use Expired - Lifetime EP0772171B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP19960116924 EP0772171B1 (en) 1995-11-03 1996-10-22 Passive intrusion detector and its use

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Application Number Priority Date Filing Date Title
EP95117323 1995-11-03
EP95117323 1995-11-03
EP19960116924 EP0772171B1 (en) 1995-11-03 1996-10-22 Passive intrusion detector and its use

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EP0772171A1 EP0772171A1 (en) 1997-05-07
EP0772171B1 true EP0772171B1 (en) 2003-01-08

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Publication number Priority date Publication date Assignee Title
DE19737166C2 (en) * 1997-08-26 2002-04-25 Esser Security Systems Gmbh PIR
GB2339614B (en) * 1998-07-14 2000-06-21 Infrared Integrated Syst Ltd Detector-array sensor with mask warning
GB9908073D0 (en) * 1999-04-09 1999-06-02 Texecom Limited Infrared detector lens
EP1061489B1 (en) * 1999-06-07 2004-08-25 Siemens Building Technologies AG Intrusion detector with a device for monitoring against tampering
ATE295593T1 (en) * 1999-08-27 2005-05-15 Siemens Building Tech Ag ROOM MONITORING DEVICE
IT1318199B1 (en) * 2000-07-19 2003-07-28 Vimar S R L Ora Vimar S P A ANTI-TAMPERING DEVICE AND RELATED METHOD FOR DETECTING THE TAMPERING OF A COMPONENT.
EP1989695B1 (en) 2006-02-20 2013-04-24 Robert Bosch GmbH Obstruction detection device
US7414236B2 (en) 2006-06-16 2008-08-19 Hong Kong Applied Science And Technology Research Institute Co., Ltd. Monitoring devices and intrusion surveillance devices
EP2498232A1 (en) 2011-03-10 2012-09-12 Siemens Aktiengesellschaft Detector

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US4405234A (en) * 1981-08-03 1983-09-20 Detector Electronics Corp. Radiation detection apparatus having refractive light checking feature
FR2520123A1 (en) * 1982-01-15 1983-07-22 Thomson Csf Automatic test equipment for opto-electronic system - has light generator and fibre=optic transmission of light onto photodetector
ATE47238T1 (en) 1985-01-08 1989-10-15 Cerberus Ag INFRARED INTRUSION DETECTOR.
JPH0241188U (en) * 1988-09-10 1990-03-22
IT1241278B (en) * 1990-10-19 1993-12-29 Elkron Spa ANTI-BLINDING DEVICE FOR COMPONENTS OF SECURITY SYSTEMS.
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GB9107062D0 (en) * 1991-04-04 1991-05-22 Racal Guardall Scotland Intruder detection arrangements and methods
JP2983423B2 (en) * 1993-12-21 1999-11-29 オプテックス株式会社 Infrared human body detector
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