EP0200186B1 - Light barrier - Google Patents

Light barrier Download PDF

Info

Publication number
EP0200186B1
EP0200186B1 EP86105818A EP86105818A EP0200186B1 EP 0200186 B1 EP0200186 B1 EP 0200186B1 EP 86105818 A EP86105818 A EP 86105818A EP 86105818 A EP86105818 A EP 86105818A EP 0200186 B1 EP0200186 B1 EP 0200186B1
Authority
EP
European Patent Office
Prior art keywords
radiation
light barrier
polarization
polarization filter
barrier system
Prior art date
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.)
Expired - Lifetime
Application number
EP86105818A
Other languages
German (de)
French (fr)
Other versions
EP0200186A2 (en
EP0200186A3 (en
Inventor
Kurt Müller
Peter Wägli
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cerberus AG
Original Assignee
Cerberus AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Cerberus AG filed Critical Cerberus AG
Priority to AT86105818T priority Critical patent/ATE64023T1/en
Publication of EP0200186A2 publication Critical patent/EP0200186A2/en
Publication of EP0200186A3 publication Critical patent/EP0200186A3/en
Application granted granted Critical
Publication of EP0200186B1 publication Critical patent/EP0200186B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/18—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength
    • G08B13/181—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using active radiation detection systems
    • G08B13/183—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using active radiation detection systems by interruption of a radiation beam or barrier

Definitions

  • the invention relates to a light barrier with a radiation source and a radiation sensor acted upon by its radiation with at least two sensor elements, means for polarizing the radiation and radiation filters differently polarized in front of the two sensor elements being provided, and the two sensor elements being connected to one another in an evaluation circuit, which different radiation of the two sensor elements emits a signal.
  • Such light barriers are known for example from DE 1 934 321 or from DE 2 014 107 and are preferably used for intrusion protection.
  • the evaluation circuit triggers an alarm signal.
  • a polarization of the radiation emanating from the radiation source and the arrangement of a similar polarization filter in front of one of the sensor elements, the other sensor element absorbing radiation that is not polarized or polarized differently, ensures that the evaluation circuit does not emit an output signal when the radiation sensor is exposed to external radiation, for example solar radiation or Scattered light is struck, the polarization of which deviates from the type of polarization of the light barrier radiation or which is unpolarized, which should normally be the case, since in this case both sensor elements are acted upon equally.
  • Such light barriers can also be used for outdoor applications in daylight.
  • the immunity to interference can be further improved by using alternating radiation of a specific frequency and tuning the evaluation circuit to this frequency.
  • a synchronization of the radiation source and the evaluation circuit has also already been described.
  • the radiation source must be connected to the radiation sensor or the circuit, so that usually an autocollimation arrangement with a spatially adjacent radiation source and radiation sensors, as well as a reflector arranged at a distance therefrom and very sensitive to contamination and misalignment is provided.
  • the range of these light barriers i.e. the safely manageable length of the monitoring path is therefore quite limited.
  • the invention has for its object to eliminate the aforementioned disadvantages of the prior art and in particular to create a light barrier, which also Outdoor applications and the presence of extraneous light as well as weather-related radiation scattering with a greater range and improved interference immunity can reliably detect an object to be detected, for example an intruder with greater sensitivity.
  • this object is achieved in that the radiation consists of two spatially offset radiation branches with different, mutually independent polarization, and that the radiation from the two radiation branches with different polarization is directed to one sensor element each.
  • radiation for example infrared or light radiation, preferably infrared with a wavelength of approximately 0.9 ⁇ m, is emitted by a radiation source 1, for example a commercially available light-emitting diode (LED), and by means of a lens 2 in the direction of the monitoring path 3 bundled.
  • a polarization filter 4 is arranged after the lens 2 and is divided into two halves with different polarization by a preferably vertical parting plane. The polarization in the two halves is independent of one another, ie radiation of one type of polarization is extinguished by the other half of the filter, and vice versa.
  • This divided polarization filter divides the radiation in the monitoring section 3 into two radiation branches 31 and 32 with correspondingly different polarization.
  • the two radiation branches partially, but not completely, overlap and are arranged next to one another, preferably horizontally next to one another.
  • the radiation from the two radiation branches 3 1 and 3 2 reaches a further polarization filter 5, which is divided into two halves and corresponds exactly to the first filter 4 with respect to the type of polarization, and two half lenses 6 1 and 6 2, which are separated by an aperture 7 and have the same separation plane as the polarization filter 5, each on a sensor element 81 or 82 of a dual radiation sensor 8, the spectral sensitivity of the radiation source 1 corresponds.
  • the radiation sensor element 8 1 receives exclusively radiation from the branch 3 1, which has been passed through by the polarization filter part 4 1, since the portion that was supplied by the other half 4 2 through that Polarization filter part 5 1 is absorbed, and vice versa, only radiation from the filter part 4 2 from the radiation branch 3 2 reaches the sensor element 8 2.
  • a clean separation of the two radiation branches is achieved, even if only relatively simple and inexpensive optical elements are used, so that a particularly large usable range of the light barrier can be achieved in a particularly simple manner, without the inevitable divergence of the radiation branches having a disruptive effect.
  • the two sensor elements 8 1 and 8 2 are connected to an evaluation circuit 9, which is designed, for example, as a differential circuit and emits a signal corresponding to the difference in the irradiation between the two elements. Due to an unpolarized or otherwise polarized external radiation, For example, sunlight or daylight, radiation is applied to both sensor elements in the same way and the evaluation circuit 9 does not emit a signal, ie extraneous radiation of this type is automatically eliminated. If radiation-scattering mist occurs in the monitoring section 3, the irradiation of both sensor elements 8 1, 8 2 is also influenced in the same way, so that no difference occurs here and the differential circuit 9 does not pass on a signal.
  • an evaluation circuit 9 Due to an unpolarized or otherwise polarized external radiation, For example, sunlight or daylight, radiation is applied to both sensor elements in the same way and the evaluation circuit 9 does not emit a signal, ie extraneous radiation of this type is automatically eliminated. If radiation-scattering mist occurs in the monitoring section 3, the irradiation of
  • the security of detection and the selectivity for an intruder can be further improved in that the evaluation circuit is designed in such a way that the signals supplied by the two sensor elements 8 1 and 8 2 must occur with a certain time difference from one another, for example within a predetermined time window, and with a certain intensity, or with other suitable criteria to trigger an alarm.
  • the evaluation circuit is designed in such a way that the signals supplied by the two sensor elements 8 1 and 8 2 must occur with a certain time difference from one another, for example within a predetermined time window, and with a certain intensity, or with other suitable criteria to trigger an alarm.
  • further information can be obtained from the signals, for example about the size and speed of the detected object.
  • the first, half-divided polarization filter 10 is arranged between the radiation source 1 and the lens 2, and the further polarization filter 11 between the half lenses 6 1, 6 2 and the radiation sensor 8.
  • the polarization filters can also be applied directly to the surfaces, i.e. the front or the back of the lens 2, or the half lenses 61 and 62 be applied. It is also possible to form the lens 2 from differently polarized parts made of polarizing material or to assemble this lens into zones with different polarization, the respective lenses on the receiver side being designed and constructed analogously.
  • the radiation branches can e.g. can also be provided in a different way.
  • they can be designed as a central part and as a ring concentrically surrounding them, and the radiation sensor accordingly with a radiation-sensitive zone in the center and a second radiation-sensitive zone surrounding it in a ring. This means that you no longer have to pay attention to the orientation during assembly.
  • FIG. 3 shows a polarization filter 4 or 5, or 10 or 11, which is divided by a vertical dividing line 12 into two halves 13 and 14 with different polarization.
  • the polarization is linear in both halves, namely in one half 13 in the vertical direction and in the other half orthogonally to it in the horizontal direction. Both types of polarization are therefore independent of one another, i.e. Radiations polarized in this way cancel each other out.
  • a linear polarization is also provided, but the two directions of polarization in the halves 13 and 14 are inclined approximately 45 ° to the horizontal or vertical. Since natural external radiation, e.g. solar radiation or sky light, if at all noteworthy, then almost are always preferably polarized either vertically or horizontally, their influence on the two sensor elements only sensitized to 45 ° polarized radiation is the same and is eliminated by the evaluation circuit.
  • the two halves 13 and 14 are not linear, but circularly polarizing.
  • the two halves have an opposite direction of rotation, i.e. the part 13 is counterclockwise and the part 14 is clockwise circularly polarizing. This also largely eliminates external radiation or makes it ineffective.
  • the dividing line 12 of the two halves 13 and 14 of the polarization filters 4 and 5 does not necessarily have to run vertically. However, the division must ensure that steel branches are formed, which are penetrated by an intruder in succession with a certain measurable time difference.
  • FIG. 6 shows an example of a suitable evaluation circuit, in which the two sensor elements 8 1 and 8 2 are designed as phototransistors Ph, which are connected to the associated resistors in an emitter follower circuit and feed their output signal via a preamplifier 15 or 16 to a sample and hold circuit .
  • the radiation source is preferably operated as a pulse emitter with a certain pulse frequency for reasons of interference immunity, and the preamplifiers are designed to be frequency-selective
  • the two sample and hold circuits 17 and 18 store the maxima of the pulses for a short time and pass them to a differential circuit 19 further, and on the other hand deliver a signal to a monitoring circuit 20 if the input pulses fail or their intensity drops below a given threshold, and indicate a fault or attempted sabotage.
  • the positive input of the differential circuit 19 is controlled by one sensor element 8 1 and the negative input by the other sensor element 8 2, a positive signal or a negative signal appears at the output of the differential circuit 19, depending on which sensor element has undergone a change in irradiation. If an object crosses the two radiation branches one after the other, a positive and a negative pulse appear in succession at short intervals.
  • the output signals of the differential circuit 19 are each fed to a positive and negative threshold value detector 21, 22, which forward the signals to two cross-connected OR gates 23, 24, provided that their intensity exceeds the predetermined threshold values.
  • the OR gates 23 and 24 give a start pulse to the start input of a counter and time window comparator 25 and the second positive or negative pulse to the stop input of this counter 25.
  • the minimum time can also be chosen to be zero, although a finite minimum time offers greater security.

Abstract

In a light barrier, especially for outside application and long distances monitored, insensitivity to interfering light and scattering through fumes or fog and an increased range and sensitivity to objects passing through the light barrier are achieved by subdividing radiation from a source into two radiation branches which are offset relative to each other and differently polarized, e.g., by means of a polarization filter divided into two parts, with different linear or oppositely circular polarization of the filter part surfaces. By means of an analogously subdivided polarization filter, the radiation of each of the two radiation branches is focused on a different individual sensor element. The two sensor elements are connected in a differential circuit which triggers an alarm signal in response to signals arriving from both radiation branches in short succession but does not trigger an alarm signal if both sensor elements are equally irradiated.

Description

Die Erfindung betrifft eine Lichtschranke mit einer Strahlunasquelle und einem von deren Strahlung beaufschlagten Strahlungssensor mit wenigstens zwei Sensorelementen, wobei Mittel zur Polarisation der Strahlung und vor den beiden Sensorelementen unterschiedlich polarisierte Strahlungsfilter vorgesehen sind, und die beiden Sensorelemente in einer Auswerteschaltung miteinander verbunden sind, welche bei unterschiedlicher Bestrahlung der beiden Sensorelemente ein Signal abgibt.The invention relates to a light barrier with a radiation source and a radiation sensor acted upon by its radiation with at least two sensor elements, means for polarizing the radiation and radiation filters differently polarized in front of the two sensor elements being provided, and the two sensor elements being connected to one another in an evaluation circuit, which different radiation of the two sensor elements emits a signal.

Solche Lichtschranken sind beispielsweise aus DE 1 934 321 oder aus DE 2 014 107 bekannt und dienen vorzugsweise dem Intrusionsschutz. Sobald dabei die von der Strahlungsquelle ausgehende, auf den Strahlungssensor gerichtete Strahlung, vorzugsweise im infraroten oder sichtbaren Spektralbereich, z-B. durch den Körper eines Einbrechers oder durch Abdeckung bei einem Sabotageversuch unterbrochen wird, löst die Auswerteschaltung ein Alarmsignal aus.Such light barriers are known for example from DE 1 934 321 or from DE 2 014 107 and are preferably used for intrusion protection. As soon as the radiation emanating from the radiation source and directed onto the radiation sensor, preferably in the infrared or visible spectral range, for example. is interrupted by the body of a burglar or by cover during an attempt at sabotage, the evaluation circuit triggers an alarm signal.

Durch eine Polarisation der von der Strahlungsquelle ausgehenden Strahlung und die Anordnung eines gleichartigen Polarisationsfilters vor einem der Sensorelemente, wobei das andere Sensorelement nicht oder anders polarisierte Strahlung aufnimmt, wird erreicht, dass die Auswerteschaltung kein Ausgangssignal abgibt, wenn der Strahlungssensor von Fremdstrahlung, z.B. Sonnenstrahlung oder Streulicht, getroffen wird, deren Polarisation von der Polarisationsart der Lichtschrankenstrahlung abweicht oder die unpolarisiert ist, was in der Regel der Fall sein dürfte, da in diesem Fall beide Sensorelemente gleich beaufschlagt werden.A polarization of the radiation emanating from the radiation source and the arrangement of a similar polarization filter in front of one of the sensor elements, the other sensor element absorbing radiation that is not polarized or polarized differently, ensures that the evaluation circuit does not emit an output signal when the radiation sensor is exposed to external radiation, for example solar radiation or Scattered light is struck, the polarization of which deviates from the type of polarization of the light barrier radiation or which is unpolarized, which should normally be the case, since in this case both sensor elements are acted upon equally.

Solche Lichtschranken können bei geeigneter Ausbildung auch für Aussenanwendungen bei Tageslicht eingesetzt werden. Dabei kann die Störsicherheit noch weiter verbessert werden, indem Wechselstrahlung bestimmter Frequenz verwendet wird und die Auswerteschaltung auf diese Frequenz abgestimmt wird. Auch eine Synchronisation von Strahlungsquelle und Auswerteschaltung ist bereits beschrieben worden. Dazu muss jedoch die Strahlungsquelle mit dem Strahlungssensor oder der Schaltung verbunden sein, so dass meist eine Autokollimations-Anordnung mit räumlich benachbarter Strahlungsquelle und Strahlungssensoren, sowie in einer Distanz davon angeordnetem, gegen Verschmutzung und Dejustierung sehr empfindlichen Reflektor vorgesehen ist. Die Reichweite dieser Lichtschranken, d.h. die sicher beherrschbare Länge der Ueberwachungsstrecke, ist daher ziemlich begrenzt.With suitable training, such light barriers can also be used for outdoor applications in daylight. The immunity to interference can be further improved by using alternating radiation of a specific frequency and tuning the evaluation circuit to this frequency. A synchronization of the radiation source and the evaluation circuit has also already been described. For this purpose, however, the radiation source must be connected to the radiation sensor or the circuit, so that usually an autocollimation arrangement with a spatially adjacent radiation source and radiation sensors, as well as a reflector arranged at a distance therefrom and very sensitive to contamination and misalignment is provided. The range of these light barriers, i.e. the safely manageable length of the monitoring path is therefore quite limited.

Lichtschranken für Aussenanwendungen mit längerer Reichweite im Bereich von mehr als 10 Metern, bis über 100 Meter sind jedoch wetterabhängig, da Nebel und Regentropfen eine Streuung der Strahlung verursachen und bei ungünstigen Wetterverhältnissen besonders bei grosser Distanz von Strahlungsquelle und Strahlungssensor eine merkbare Schwächung der empfangenen Strahlung bewirkt. Um dabei kein fehlerhaftes Alarmsignal auszulösen, muss daher die Empfindlichkeit der Auswerteschaltung entsprechend reduziert werden. Hinzu kommt, dass durch eine wetterbedingte Verbreiterung des Ueberwachungsstrahles infolge der Strahlungsstreuung die Strahlungsschwächung durch ein Objekt, z.B. einen Eindringling geringer wird, so dass ein Eindringling bei ungünstigen Wetterverhältnissen gar nicht mehr erkannt werden kann, da trotzdem noch genügend Streustrahlung auf den Sensor trifft.Light barriers for outdoor applications with a longer range in the range of more than 10 meters, but up to more than 100 meters are dependent on the weather, since fog and raindrops scatter the radiation and, in unfavorable weather conditions, cause a noticeable weakening of the radiation received, especially when the radiation source and radiation sensor are far away . In order not to trigger a faulty alarm signal, the sensitivity of the evaluation circuit must be reduced accordingly. In addition, due to a weather-related broadening of the monitoring beam as a result of the radiation scattering, the radiation attenuation by an object, e.g. an intruder is reduced, so that an intruder can no longer be recognized in unfavorable weather conditions, because enough scattered radiation still strikes the sensor.

Der Erfindung liegt die Aufgabe zugrunde, die vorstehend erwähnten Nachteile des Standes der Technik zu beseitigen und insbesondere eine Lichtschranke zu schaffen, die auch bei Aussenanwendungen und Vorhandensein von Fremdlicht sowie wetterbedingeter Strahlungsstreuung mit grösserer Reichweite bei verbesserter Störsicherheit ein nachzuweisendes Objekt, z.B. einen Eindringling mit grösserer Empfindlichkeit sicher zu detektieren vermag.The invention has for its object to eliminate the aforementioned disadvantages of the prior art and in particular to create a light barrier, which also Outdoor applications and the presence of extraneous light as well as weather-related radiation scattering with a greater range and improved interference immunity can reliably detect an object to be detected, for example an intruder with greater sensitivity.

Erfindungsgemäss wird diese Aufgabe dadurch gelöst, dass die Strahlung aus zwei räumlich gegeneinander versetzten Strahlungszweigen mit unterschiedlicher, voneinander unabhängigen Polarisation besteht, und dass die Strahlung aus den beiden Strahlungszweigen mit unterschiedlicher Polarisation auf je ein Sensorelement geleitet wird.According to the invention, this object is achieved in that the radiation consists of two spatially offset radiation branches with different, mutually independent polarization, and that the radiation from the two radiation branches with different polarization is directed to one sensor element each.

Eine unterschiedliche, voneinander unabhängige Polarisation in den beiden Strahlungszweigen kann beispielsweise dadurch erreicht werden, dass beide Strahlungszweige mittels geeigneter Polarisationsfilter nach der Strahlungsquelle linear polarisiert werden, und zwar orthogonal zueinander. Mit Vorteil werden die Polarisationsebenen dabei um 45° gegen die Horizontale oder Vertikale geneigt gewählt, um elliptisch polarisiertes Fremdlicht mit vertikaler und horizontaler Hauptachse, z.B. Sonnenlicht unwirksam zu machen, da dieses bei einer Neigung von 45° beide Sensorelemente gleich beaufschlagt. Auch eine zirkulare Polarisation mit entgegengesetztem Drehsinn kann mit Vorteil verwendet werden. Vor dem Strahlungssensor ist dann jeweils eine entsprechende Polarisationsfilter-Kombination vorzusehen, welche, gegebenenfalls in Zusammenwirken mit geeigneten optischen Elementen jeweils die polarisierte Strahlung aus dem einen Strahlungszweig auf das eine Sensorelement und die Strahlung aus dem anderen Strahlungszweig auf das andere Sensorelement leitet. Durch die Verwendung einer solchen Polarisationsfilter-Kombination vor dem Strahlungssensor wird es möglich, Strahlung unterschiedlicher Polarisation auch dann voneinander zu trennen, wenn die beiden Strahlungszweige sich teilweise überdecken, was eine noch grössere Reichweite zu erreichen erlaubt. Die Erfindung sowie zweckmässige und vorteilhafte Weiterbildungen derselben werden an Hand der in der Figuren dargestellten Ausführungsbeispiele näher erläutert.

  • Figur 1 zeigt eine erste Ausführungsform einer Lichtschranke,
  • Figur 2 zeigt eine zweite Ausführungsform einer Lichtschranke,
  • Figur 3 zeigt Polarisationsfilter mit linearer Polarisation,
  • Figur 4 zeigt Polarisationsfilter mit linearer Polarisation, wobei die Polarisationsebene um ca. 45° gegen die Horizontale geneigt ist.
  • Figur 5 zeigt Polarisationsfilter mit zirkularer Polarisation,
  • Figur 6 zeigt eine Auswerteschaltung.
A different, mutually independent polarization in the two radiation branches can be achieved, for example, in that both radiation branches are linearly polarized by means of suitable polarization filters after the radiation source, specifically orthogonally to one another. Advantageously, the polarization planes are chosen to be inclined at 45 ° to the horizontal or vertical in order to render elliptically polarized extraneous light with vertical and horizontal main axes, for example sunlight, ineffective, since this affects both sensor elements equally at an inclination of 45 °. Circular polarization with the opposite direction of rotation can also be used with advantage. A corresponding polarization filter combination is then to be provided in front of the radiation sensor, which, if appropriate in cooperation with suitable optical elements, directs the polarized radiation from one radiation branch to one sensor element and the radiation from the other radiation branch to the other sensor element. By using such a polarization filter combination in front of the radiation sensor, it is possible to separate radiation of different polarizations from one another even when the two radiation branches partially overlap, which allows an even greater range to be achieved. The invention and the expedient and advantageous developments of the same are explained in more detail with reference to the exemplary embodiments shown in the figures.
  • FIG. 1 shows a first embodiment of a light barrier,
  • FIG. 2 shows a second embodiment of a light barrier,
  • FIG. 3 shows polarization filters with linear polarization,
  • FIG. 4 shows polarization filters with linear polarization, the plane of polarization being inclined by approximately 45 ° to the horizontal.
  • FIG. 5 shows polarization filters with circular polarization,
  • Figure 6 shows an evaluation circuit.

Bei der in Figur 1 dargestellten Lichtschranke wird vom einer Strahlungsquelle 1, z.B. einer handelsüblichen lichtemittierenden Diode (LED) Strahlung, z.B. Infrarot- oder Lichtstrahlung, vorzugsweise Infrarot mit ca. 0,9 µm Wellenlänge, ausgestrahlt und mittels einer Linse 2 in Richtung der Ueberwachungsstrecke 3 gebündelt. Nach der Linse 2 ist ein Polarisationsfilter 4 angeordnet, das durch eine vorzugsweise vertikale Trennebene in zwei Hälften mit unterschiedlicher Polarisation geteilt ist. Die Polarisation in den beiden Hälften ist dabei unabhängig voneinander, d.h. Strahlung der einen Polarisationsart wird von der anderen Hälfte des Filters ausgelöscht, und umgekehrt. Durch dieses geteilte Polarisationsfilter wird die Strahlung in der Ueberwachungsstrecke 3 in zwei Strahlungszweige 3¹ und 3² mit entsprechend unterschiedlicher Polarisation geteilt. Im dargestellten Beispiel, bei Verwendung einer einfachen Sammellinse 2 überdecken sich beide Strahlungszweige teilweise, aber nicht vollständig, und sind nebeneinander, vorzugsweise horizontal nebeneinander, angeordnet.In the light barrier shown in FIG. 1, radiation, for example infrared or light radiation, preferably infrared with a wavelength of approximately 0.9 μm, is emitted by a radiation source 1, for example a commercially available light-emitting diode (LED), and by means of a lens 2 in the direction of the monitoring path 3 bundled. A polarization filter 4 is arranged after the lens 2 and is divided into two halves with different polarization by a preferably vertical parting plane. The polarization in the two halves is independent of one another, ie radiation of one type of polarization is extinguished by the other half of the filter, and vice versa. This divided polarization filter divides the radiation in the monitoring section 3 into two radiation branches 31 and 32 with correspondingly different polarization. In the example shown, when using a simple converging lens 2, the two radiation branches partially, but not completely, overlap and are arranged next to one another, preferably horizontally next to one another.

Die Strahlung aus den beiden Strahlungszweigen 3¹ und 3² gelangt über ein weiteres in zwei Hälften geteiltes und bezüglich der Polarisationsart genau dem ersten Filter 4 entsprechendes Polisarisationsfilter 5 und zwei Halblinsen 6¹ und 6², die durch eine Blende 7 getrennt sind und dieselbe Trennebene aufweisen wie das Polarisationsfilter 5, auf je ein Sensorelement 8¹ bzw. 8² eines Dual-Strahlungssensors 8, dessen spektrale Empfindlichkeit der Strahlungsquelle 1 entspricht.The radiation from the two radiation branches 3 1 and 3 2 reaches a further polarization filter 5, which is divided into two halves and corresponds exactly to the first filter 4 with respect to the type of polarization, and two half lenses 6 1 and 6 2, which are separated by an aperture 7 and have the same separation plane as the polarization filter 5, each on a sensor element 8¹ or 8² of a dual radiation sensor 8, the spectral sensitivity of the radiation source 1 corresponds.

Obwohl sich die beiden Strahlungszweige 3¹ und 3² im mittleren Bereich etwas überschneiden, erhält dabei das Strahlungssensor-Element 8¹ ausschliesslich Strahlung aus dem Zweig 3¹, die vom Polarisationsfilterteil 4¹ durchgelassen wurde, da der Anteil, der von der anderen Hälfte 4² geliefert wurde, durch das Polarisationsfilterteil 5¹ absorbiert wird, und umgekehrt gelangt auf das Sensorelement 8² ausschliesslich Strahlung vom Filterteil 4² aus dem Strahlungszweig 3². Auf diese Weise wird eine saubere Trennung beider Strahlungszweige erreicht, auch wenn nur relativ einfache und kostengünstige optische Elemente verwendet werden, so dass sich auf besonders einfache Weise eine besonders grosse nutzbare Reichweite der Lichtschranke erreichen lässt, ohne dass die unvermeidliche Divergenz der Strahlungszweige störend wirkt. Selbstverständlich können statt einfacher Sammellinsen jedoch auch komplizierter aufgebaute Optiken mit besserer Präzision verwendet werden, mit denen die beiden Strahlungszweige noch besser voneinander getrennt gehalten werden können und somit die Reichweite der Lichtschranke und ihre Verwendbarkeit unter ungünstigen Wetterbedingungen weiter verbesserbar sind.Although the two radiation branches 3 1 and 3 2 overlap somewhat in the middle region, the radiation sensor element 8 1 receives exclusively radiation from the branch 3 1, which has been passed through by the polarization filter part 4 1, since the portion that was supplied by the other half 4 2 through that Polarization filter part 5 1 is absorbed, and vice versa, only radiation from the filter part 4 2 from the radiation branch 3 2 reaches the sensor element 8 2. In this way, a clean separation of the two radiation branches is achieved, even if only relatively simple and inexpensive optical elements are used, so that a particularly large usable range of the light barrier can be achieved in a particularly simple manner, without the inevitable divergence of the radiation branches having a disruptive effect. Of course, instead of simple converging lenses, it is also possible to use more complex optics with better precision, with which the two radiation branches can be kept even better apart and thus the range of the light barrier and its usability under unfavorable weather conditions can be further improved.

Die beiden Sensorelemente 8¹ und 8² sind an eine Auswerteschaltung 9 angeschlossen, die z.B. als Differenzschaltung ausgebildet ist und ein Signal entsprechend dem Unterschied der Bestrahlung beider Elemente abgibt. Durch eine unpolarisierte oder in anderer Weise polarisierte Fremdstrahlung, z.B. Sonnen- oder Tageslicht, werden beide Sensorelemente in gleicher Weise von Strahlung beaufschlagt und die Auswerteschaltung 9 gibt kein Signal ab, d.h. Fremdstrahlung dieser Art wird automatisch eliminiert. Bei Auftreten von strahlungsstreuendem Nebel in der Ueberwachungsstrecke 3 wird ebenfalls die Bestrahlung beider Sensorelemente 8¹ ,8² in gleicher Weise beeinflusst, so dass auch hier keine Differenz auftritt und die Differenzschaltung 9 kein Signal weitergibt. Es kann also auch unter ungünstigen Umständen, d.h. bei Anwesenheit von Fremdstrahlung, bei Nebel oder Regen, und bei sehr grosser Reichweite oder Ueberwachungsstreckenlänge mit unverminderter oder sogar noch verbesserter Empfindlichkeit gearbeitet werden, ohne dass die Lichtschranke unempfindlich wird oder ein fehlerhaftes Signal gibt. Ein echter Eindringling wird dagegen die beiden räumlich gegeneinander versetzten Strahlungszweige 3¹ , 3² nacheinander durchqueren und dabei je ein Differenzsignal erzeugen, d.h. ein Eindringling wird in jedem Fall mit grosser Sicherheit ein Alarmsignal auslösen. Die Nachweissicherheit und die Selektivität für einen Eindringling kann dabei noch dadurch verbessert werden, dass die Auswerteschaltung so ausgebildet wird, dass die von den beiden Sensorelemente 8¹ und 8² gelieferten Signale mit einer bestimmten Zeitdifferenz zueinander auftreten müssen, z.B. innerhalb eines vorgegebenen Zeitfensters, und mit einer bestimmten Intensität, oder mit anderen geeigneten Kriterien, um einen Alarm auslösen zu können. Aus den Signalen können mit einer geeignet ausgebildeten Schaltung auch noch weitere Informationen, z.B. über Grösse und Geschwindigkeit des detektierten Objektes, gewonnen werden.The two sensor elements 8 1 and 8 2 are connected to an evaluation circuit 9, which is designed, for example, as a differential circuit and emits a signal corresponding to the difference in the irradiation between the two elements. Due to an unpolarized or otherwise polarized external radiation, For example, sunlight or daylight, radiation is applied to both sensor elements in the same way and the evaluation circuit 9 does not emit a signal, ie extraneous radiation of this type is automatically eliminated. If radiation-scattering mist occurs in the monitoring section 3, the irradiation of both sensor elements 8 1, 8 2 is also influenced in the same way, so that no difference occurs here and the differential circuit 9 does not pass on a signal. It is therefore possible to work with undiminished or even improved sensitivity even under unfavorable circumstances, ie in the presence of extraneous radiation, in fog or rain, and with a very long range or monitoring path length, without the light barrier becoming insensitive or giving a faulty signal. A real intruder, on the other hand, will cross the two spatially offset radiation branches 3¹, 3² one after the other and each generate a differential signal, ie an intruder will trigger an alarm signal with great certainty. The security of detection and the selectivity for an intruder can be further improved in that the evaluation circuit is designed in such a way that the signals supplied by the two sensor elements 8 1 and 8 2 must occur with a certain time difference from one another, for example within a predetermined time window, and with a certain intensity, or with other suitable criteria to trigger an alarm. With a suitably designed circuit, further information can be obtained from the signals, for example about the size and speed of the detected object.

Bei dem in Figur 2 dargestellten Ausführungsbeispiel, bei dem identische Elemente mit den gleichen Bezugszeichen versehen sind, wie in der vorstehend beschriebenen Lichtschranke, ist das erste, hälftig geteilte Polarisationsfilter 10 zwischen der Strahlungsquelle 1 und der Linse 2 angeordnet, und das weitere Polarisationsfilter 11 zwischen den Halblinsen 6¹, 6² und dem Strahlungssensor 8.In the embodiment shown in Figure 2, in which identical elements are provided with the same reference numerals as in the light barrier described above, the first, half-divided polarization filter 10 is arranged between the radiation source 1 and the lens 2, and the further polarization filter 11 between the half lenses 6 1, 6 2 and the radiation sensor 8.

Stattdessen können die Polarisationsfilter auch direkt auf die Oberflächen, d.h. die Vorderseite oder die Rückseite der Linse 2, bzw. der Halblinsen 6¹ und 6² aufgebracht sein. Es ist auch möglich, die Linse 2 aus unterschiedlich polarisierten Teilen aus polarisierendem Material auszubilden oder diese Linse Zonen mit unterschiedlicher Polarisation zusammenzusetzen, wobei jeweils die empfängerseitigen Linsen analog ausgeführt und aufgebaut sind.Instead, the polarization filters can also be applied directly to the surfaces, i.e. the front or the back of the lens 2, or the half lenses 6¹ and 6² be applied. It is also possible to form the lens 2 from differently polarized parts made of polarizing material or to assemble this lens into zones with different polarization, the respective lenses on the receiver side being designed and constructed analogously.

Auch weitere Abwandlungen sind im Rahmen der Erfindung möglich. Statt einer Anordnung der Strahlungszweige horizontal nebeneinder können diese z.B. auch in anderer Weise vorgesehen sein. So können diese etwa als zentraler Teil und als diesen konzentrisch umgebenden Ring ausgeführt sein, und der Strahlungssensor entsprechend mit einer strahlungsempfindlichen Zone im Zentrum und einer diese ringförmig umgebenden zweiten strahlungsempfindlichen Zone. Damit muss bei der Montage nicht mehr auf die Orientierung geachtet werden.Further modifications are also possible within the scope of the invention. Instead of arranging the radiation branches horizontally next to each other, they can e.g. can also be provided in a different way. For example, they can be designed as a central part and as a ring concentrically surrounding them, and the radiation sensor accordingly with a radiation-sensitive zone in the center and a second radiation-sensitive zone surrounding it in a ring. This means that you no longer have to pay attention to the orientation during assembly.

Figur 3 zeigt ein Polarisationsfilter 4 oder 5, bzw. 10 oder 11, das durch eine vertikale Trennlinie 12 in zwei Hälften 13 und 14 mit unterschiedlicher Polarisation unterteilt wird. Die Polarisation ist in beiden Hälften linear, und zwar in einer Hälfte 13 in vertikaler und in der anderen Hälfte orthogonal dazu in horizontaler Richtung. Beide Polarisationsarten sind also voneinander unabhängig, d.h. derart polarisierte Strahlungen löschen sich gegenseitig aus.FIG. 3 shows a polarization filter 4 or 5, or 10 or 11, which is divided by a vertical dividing line 12 into two halves 13 and 14 with different polarization. The polarization is linear in both halves, namely in one half 13 in the vertical direction and in the other half orthogonally to it in the horizontal direction. Both types of polarization are therefore independent of one another, i.e. Radiations polarized in this way cancel each other out.

Bei dem in Figur 4 dargestellten Polarisationsfilter ist ebenfalls eine lineare Polarisation vorgesehen, jedoch sind die beiden Polarisationsrichtungen in den Hälften 13 und 14 etwa 45° gegen die Horizontale oder Vertikale geneigt. Da natürliche Fremdstrahlungen, z.B. Sonnenstrahlung oder Himmelslicht, wenn überhaupt nennenswert, dann fast immer bevorzugt entweder vertikal oder horizontal polarisiert sind, so ist deren Einfluss auf die beiden nur für 45°-polarisierte Strahlung sensibilisierten Sensorelemente gleich und wird durch die Auswerteschaltung eliminiert.In the polarization filter shown in Figure 4, a linear polarization is also provided, but the two directions of polarization in the halves 13 and 14 are inclined approximately 45 ° to the horizontal or vertical. Since natural external radiation, e.g. solar radiation or sky light, if at all noteworthy, then almost are always preferably polarized either vertically or horizontally, their influence on the two sensor elements only sensitized to 45 ° polarized radiation is the same and is eliminated by the evaluation circuit.

Bei der in Figur 5 gezeigten Ausführungsform eines Polarisationsfilters sind die beiden Hälften 13 und 14 nicht linear, sondern zirkular polarisierend ausgebildet. Die beiden Hälften haben dabei einen entgegengesetzten Drehsinn, d.h. der Teil 13 ist linksdrehend, und der Teil 14 rechtsdrehend zirkular polarisierend ausgebildet. Auch hierdurch können Fremdstrahlungen weitgehend eliminiert oder unwirksam gemacht werden.In the embodiment of a polarization filter shown in FIG. 5, the two halves 13 and 14 are not linear, but circularly polarizing. The two halves have an opposite direction of rotation, i.e. the part 13 is counterclockwise and the part 14 is clockwise circularly polarizing. This also largely eliminates external radiation or makes it ineffective.

Wie bereits erwähnt, muss die Trennungslinie 12 der beiden Hälften 13 und 14 der Polarisationsfilter 4 und 5 nicht unbedingt vertikal verlaufen. Durch die Aufteilung muss jedoch gewährleistet sein, dass Stahlungszweige gebildet werden, die von einem Eindringling nacheinander mit einer gewissen messbaren Zeitdifferenz durchquert werden.As already mentioned, the dividing line 12 of the two halves 13 and 14 of the polarization filters 4 and 5 does not necessarily have to run vertically. However, the division must ensure that steel branches are formed, which are penetrated by an intruder in succession with a certain measurable time difference.

Figur 6 zeigt ein Beispiel einer geeigneten Auswerteschaltung, bei dem die beiden Sensorelemente 8¹ und 8² als Phototransistoren Ph ausgebildet sind, die mit zugehörigen Widerständen in Emitterfolgerschaltung liegen und ihr Ausgangssignal über je einen Vorverstärker 15, bzw. 16 je einer Sample & Hold-Schaltung zuleiten. Da die Strahlungsquelle aus Gründen der Störsicherheit vorzugsweise als Impulsstrahler mit einer bestimmten Impulsfrequenz betrieben wird, und die Vorverstärker entsprechend frequenzselektiv ausgebildet sind, speichern die beiden Sample & Hold-Schaltungen 17 und 18 die Maxima der Impulse für eine kurze Zeit und geben sie an eine Differenzschaltung 19 weiter, und liefern andererseits an eine Ueberwachungsschaltung 20 ein Signal, falls die Eingangsimpulse ausbleiben oder deren Intensität unter eine gegebene Schwelle sinkt, und zeigen eine Störung oder Sabotageversuch an.FIG. 6 shows an example of a suitable evaluation circuit, in which the two sensor elements 8 1 and 8 2 are designed as phototransistors Ph, which are connected to the associated resistors in an emitter follower circuit and feed their output signal via a preamplifier 15 or 16 to a sample and hold circuit . Since the radiation source is preferably operated as a pulse emitter with a certain pulse frequency for reasons of interference immunity, and the preamplifiers are designed to be frequency-selective, the two sample and hold circuits 17 and 18 store the maxima of the pulses for a short time and pass them to a differential circuit 19 further, and on the other hand deliver a signal to a monitoring circuit 20 if the input pulses fail or their intensity drops below a given threshold, and indicate a fault or attempted sabotage.

Da der positive Eingang der Differenzschaltung 19 von dem einen Sensorelement 8¹ und der negative Eingang vom anderen Sensorelement 8² angesteuert wird, erscheint am Ausgang der Differenzschaltung 19 ein positives Signal, bzw. ein negatives Signal, je nachdem, welches Sensorelement eine Bestrahlungsänderung erfahren hat. Werden die beiden Strahlungszweige nacheinander von einem Objekt durchquert, so erscheint also nacheinander in kurzem Zeitabstand ein positiver und ein negativer Impuls. Die Ausgangssignale der Differenzschaltung 19 werden je einem positiven und negativen Schwellenwertdetektor 21, 22 zugeführt, die die Signale an zwei kreuzweise geschaltete ODER-Tore 23, 24 weiterleiten, sofern deren Intensität die vorgegebenen Schwellenwerte übersteigen. Die ODER-Tore 23 und 24 geben bei Auftreten eines ersten positiven oder negativen Impulses einen Startimpuls an den Starteingang eines Zählers und Zeitfensterkomparators 25 und den zweiten positiven oder negativen Impuls an den Stopeingang dieses Zählers 25. Dieser ist nun so ausgebildet, dass er ein Signal an einen Alarmsignalgeber 26 abgibt, wenn der Zweite oder Stopimpuls innerhalb eines vorgegebenen Zeitfensters liegt, d.h. wenn der zweite Impuls frühestens nach einer bestimmten Minimalzeit, aber spätestens nach einer vorgegebenen Maximalzeit eintrifft. Die Minimalzeit kann auch Null gewählt werden, wenngleich eine endliche Minimalzeit eine grössere Sicherheit bietet. Nach Ablauf der vorgegebenen Maximalzeit wird der Stopeingang blockiert und der Zähler automatisch zurückgestellt, so dass die Schaltung wiederum betriebsbereit ist.Since the positive input of the differential circuit 19 is controlled by one sensor element 8 1 and the negative input by the other sensor element 8 2, a positive signal or a negative signal appears at the output of the differential circuit 19, depending on which sensor element has undergone a change in irradiation. If an object crosses the two radiation branches one after the other, a positive and a negative pulse appear in succession at short intervals. The output signals of the differential circuit 19 are each fed to a positive and negative threshold value detector 21, 22, which forward the signals to two cross-connected OR gates 23, 24, provided that their intensity exceeds the predetermined threshold values. When a first positive or negative pulse occurs, the OR gates 23 and 24 give a start pulse to the start input of a counter and time window comparator 25 and the second positive or negative pulse to the stop input of this counter 25. This is now designed to generate a signal outputs to an alarm signal generator 26 if the second or stop pulse lies within a predetermined time window, ie if the second pulse arrives after a certain minimum time at the earliest, but after a predetermined maximum time at the latest. The minimum time can also be chosen to be zero, although a finite minimum time offers greater security. After the specified maximum time has elapsed, the stop input is blocked and the counter is automatically reset so that the circuit is again ready for operation.

Es versteht sich, dass statt der beschriebenen Schaltung auch andere Schaltungen mit analoger und äquivalenter Funktion verwendet werden können.It goes without saying that, instead of the circuit described, other circuits with an analog and equivalent function can also be used.

Claims (10)

  1. A light barrier system for intrusion detection comprising a radiation source (1) and a radiation sensor (8) receiving the radiation from said radiation source (1) and at least two sensor elements (8¹, 8²), wherein in the path of radiation a first polarization filter (4) is provided for producing polarized radiation and a second polarization filter (5) is provided in front of the sensor elements (8¹, 8²) for filtering the radiation and the two sensor elements (8¹, 8²) are functionally connected with an evaluation circuit (9) which produces an alarm signal in response to different radiation being received by the two sensor elements (8¹, 8²), characterized in that the radiation source (1) and the radiation sensor (8) are arranged on different sides of the monitored section (3) that the first polarization filter (4) is constructed in such manner that in the monitored section (3) are generated two radiation branches (3¹, 3²) comprising radiation of different independent polarization and being spatially offset from each other and that the second polarization filter (5) is constructed in such manner that the radiation with different polarization from the two radiation branches (3¹, 3²) is directed to one of the sensor elements (8¹, 8²).
  2. Light barrier system according to patent claim 1, characterized in that on the side of the radiation source (1) and on the side of the radiation sensor (8) a polarization filter (4, 5) comprising two polarization filter parts (13, 14) is provided each of the polarization filter parts (13, 14) polarizing the radiation in a linear manner to produce polarization planes orthogonal to each other.
  3. Light barrier system according to patent claim 2, characterized in that the polarization planes of the two polarization filter parts (13, 14) are inclined at an angle of 45° relative to the horizontal plane.
  4. Light barrier system according to patent claim 1, characterized in that on the side of the radiation source (1) and on the side of the radiation sensor (8) a polarization filter (4, 5) comprising two polarization filter parts (13, 14) is provided each of the polarization filter parts (13, 14) polarizing the radiation in a circular manner opposite to each other.
  5. Light barrier system according to any of the patent claims 1 to 4, characterized in that the two radiation branches (3¹, 3²) spatially offset from each other overlap partially but not completely.
  6. Light barrier system according to any of the patent claims 1 to 5, characterized in that the two radiation branches (3¹, 3²) spatially offset from each other are arranged horizontally side-by-side.
  7. Light barrier system according to any of the patent claims 1 to 5, characterized in that the two radiation branches (3¹, 3²) spatially offset from each other are arranged concentically relative to each other.
  8. Light barrier system according to any of the patent claims 1 to 7, characterized in that the evaluation circuit (9) comprises a differential circuit (19) which produces a signal having a characteristic dependent on the difference of the output signals of the sensor elements (8¹, 8²).
  9. Light barrier system according to patent claim 8, characterized in that the evaluation circuit (9) comprises threshold value circuits (21, 22) which produce a signal when the output signal of the differential cicuit (19) exceeds or falls below predefined maximum and minimum threshold values.
  10. Light barrier system according to any of the patent claims 8 and 9, characterized in that the evaluation circuit (9) comprises a time window comparator (25) which triggers an alarm signal when after receipt of an output signal from one of the sensor elements (8¹, 8²) within a predetermined time period an output signal arrives from the other sensor element (8¹, 8²).
EP86105818A 1985-04-30 1986-04-26 Light barrier Expired - Lifetime EP0200186B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86105818T ATE64023T1 (en) 1985-04-30 1986-04-26 PHOTOELECTRIC BARRIER.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH1825/85 1985-04-30
CH1825/85A CH667340A5 (en) 1985-04-30 1985-04-30 PHOTOELECTRIC BARRIER.

Publications (3)

Publication Number Publication Date
EP0200186A2 EP0200186A2 (en) 1986-11-05
EP0200186A3 EP0200186A3 (en) 1987-01-21
EP0200186B1 true EP0200186B1 (en) 1991-05-29

Family

ID=4219477

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86105818A Expired - Lifetime EP0200186B1 (en) 1985-04-30 1986-04-26 Light barrier

Country Status (5)

Country Link
US (1) US4734575A (en)
EP (1) EP0200186B1 (en)
AT (1) ATE64023T1 (en)
CH (1) CH667340A5 (en)
DE (1) DE3679443D1 (en)

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3641926C1 (en) * 1986-12-09 1988-04-28 Sick Optik Elektronik Erwin Autocollimation light curtain
DE3733656C1 (en) * 1987-10-05 1989-02-02 Hoermann Kg Retro-reflective sensor
EP0388352A1 (en) * 1989-03-15 1990-09-19 Elesta Ag Elektronik One way light barrier arrangement
NL8902314A (en) * 1989-09-15 1991-04-02 Michiel Kassies METHOD AND APPARATUS FOR DETECTING AN ARTICLE
US5955854A (en) * 1992-09-29 1999-09-21 Prospects Corporation Power driven venting of a vehicle
ATE230493T1 (en) * 1997-11-07 2003-01-15 Leuze Electronic Gmbh & Co OPTOELECTRONIC DEVICE
DE102004017183A1 (en) * 2004-04-07 2005-11-10 Siemens Ag Overall system, especially medical equipment
SG189800A1 (en) * 2008-04-17 2013-05-31 Shilat Optronics Ltd Intrusion warning system
EP2359593B1 (en) 2008-11-25 2018-06-06 Tetravue, Inc. Systems and methods of high resolution three-dimensional imaging
JP5458813B2 (en) * 2009-11-10 2014-04-02 オムロン株式会社 Photoelectric sensor
EP2813868B1 (en) * 2013-06-11 2021-08-04 Rockwell Automation Switzerland GmbH Method for synchronizing optical units of a photoelectric barrier and light curtain
US10104365B2 (en) 2014-04-26 2018-10-16 Tetravue, Inc. Method and system for robust and extended illumination waveforms for depth sensing in 3D imaging
DE102014013326A1 (en) * 2014-09-15 2016-03-17 Imos Gubela Gmbh Optical sensor system
EP3423858B1 (en) 2016-02-29 2023-12-06 nLIGHT, Inc. 3d imaging system and method
US11212512B2 (en) 2017-12-28 2021-12-28 Nlight, Inc. System and method of imaging using multiple illumination pulses

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2457502A (en) * 1944-08-09 1948-12-28 Shepherd Judson O'd Signal system employing polarized light
US3440427A (en) * 1966-04-12 1969-04-22 Philips Corp Remote control system with a unitary cell bridge circuit
GB1214981A (en) * 1967-05-05 1970-12-09 John Horrocks Control means using light filters
DE1946993A1 (en) * 1969-09-17 1971-03-25 Sick Erwin Fa Light barrier for analog measuring purposes
US4333008A (en) * 1975-04-21 1982-06-01 Sanders Associates, Inc. Polarization coded doublet laser detection system
FR2347666A1 (en) * 1976-04-09 1977-11-04 France Etat AUTOMATIC TWO WAVELENGTH PHOTOELASTICIMETER
US4342987A (en) * 1979-09-10 1982-08-03 Rossin Corporation Intruder detection system
US4339660A (en) * 1980-05-15 1982-07-13 Erwin Sick Gmbh Optik-Elektronik Reflection light barrier apparatus for recognizing both strongly and weakly reflecting objects

Also Published As

Publication number Publication date
US4734575A (en) 1988-03-29
EP0200186A2 (en) 1986-11-05
DE3679443D1 (en) 1991-07-04
CH667340A5 (en) 1988-09-30
EP0200186A3 (en) 1987-01-21
ATE64023T1 (en) 1991-06-15

Similar Documents

Publication Publication Date Title
EP0200186B1 (en) Light barrier
EP0360126B2 (en) Operation method for an optical smoke detector and smoke detector for carrying out the method
EP0220361B1 (en) Surface protection
DE3041737C2 (en) Passive infrared intrusion detector
DE2824583C3 (en) Reflective light barrier for the detection of highly reflective objects within a monitoring path traversed by a bundle of rays
EP0328709B1 (en) Light barrier
EP2317347A2 (en) Optical sensor
EP0926646A1 (en) Optical smoke detector
DE3733656C1 (en) Retro-reflective sensor
CH671838A5 (en)
EP1995610B1 (en) Optoelectronic sensor assembly
EP1780559B1 (en) Optical sensor
DE19913156B4 (en) Optoelectronic device
DE10016892B4 (en) Optoelectronic device
DE2703225A1 (en) Beam interruption smoke detector - has LED's with ring connected power supply arranged round room to focus beams on to central light sensitive receiver
DE3518262C2 (en)
DE102018117878A1 (en) Safety Light Curtain
DE8609515U1 (en) Device for sabotage monitoring on an IR motion detector
DE2262118A1 (en) FAILURE-PROOF ALARM SYSTEM
DE19614872C1 (en) Light sensor for detecting object in monitoring region on detection plane
EP0133990B1 (en) Smoke sensor arrangement operating by the extinguish principle, and fire assembly having such a smoke sensor arrangement
EP1265205B1 (en) Linear smoke detector
DE2129666B2 (en) Surface penetration monitoring appts. - has spot light source in focal point of curved optical element and triple mirror reflection system
DE2823957A1 (en) Light absorption smoke detector - is insensitive to position of light beam reflectors due to multi-facet surface of remote reflector
EP1456493B1 (en) Door monitoring device

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19860426

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE CH DE FR GB IT LI NL SE

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT BE CH DE FR GB IT LI NL SE

17Q First examination report despatched

Effective date: 19890912

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE FR GB IT LI NL SE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19910529

Ref country code: NL

Effective date: 19910529

Ref country code: BE

Effective date: 19910529

REF Corresponds to:

Ref document number: 64023

Country of ref document: AT

Date of ref document: 19910615

Kind code of ref document: T

ITF It: translation for a ep patent filed

Owner name: JACOBACCI & PERANI S.P.A.

REF Corresponds to:

Ref document number: 3679443

Country of ref document: DE

Date of ref document: 19910704

ET Fr: translation filed
GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
NLV1 Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Effective date: 19920426

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19940309

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19940316

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19940406

Year of fee payment: 9

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19950426

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19950517

Year of fee payment: 10

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19950426

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19951229

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19960103

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19960430

Ref country code: CH

Effective date: 19960430

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050426