JP4582622B2 - Adjusting the warning range of passive infrared sensors - Google Patents

Description

  The present invention relates to a passive infrared sensor that detects whether or not an object is present within the alert range by detecting heat rays radiated from the object, and in particular, adjusts the alert range for detecting the presence or absence of the object. On how to do.

  A passive infrared sensor (hereinafter simply referred to as a sensor) uses an infrared detection element having sensitivity in the wavelength region of a heat ray such as a pyroelectric element, and uses the heat ray emitted from an object by a condensing optical system as an infrared detection element. It is configured to detect the presence of a moving object such as a human body when the amount of fluctuation of heat ray energy based on the output of the infrared detection element exceeds a predetermined level. Widely used for intruder detection in security systems.

  In designing the sensor, it is natural that the warning range is predetermined. In the present specification, the alert range includes not only the longest detection distance from the sensor to an object that can be detected by the sensor but also the arrangement of detection zones formed by the infrared detection element and the condensing optical system. .

However, in reality, the alert range required according to the situation of the location where the sensor is actually installed is different from the alert range determined at the time of sensor design. Therefore, in the sensor, the warning range can be adjusted according to the situation of the installation location. As a means for that, in the case of a sensor using a reflecting mirror as a condensing optical system, the angle of the reflecting mirror is usually adjustable, but the relative position between the infrared detecting element and the condensing optical system is adjusted. (For example, refer to Patent Document 1), or by using a change-over switch, a condensing optical system, an infrared detection element, and a circuit system subsequent to the infrared detection element may or may not be used. In some cases, this is possible (see, for example, [0020] stage of Patent Document 2).
Japanese Patent No. 3086406 Japanese Patent Laid-Open No. 2000-282839

  However, when the angle of the reflecting mirror can be adjusted or the relative position between the infrared detecting element and the condensing optical system can be adjusted as in Patent Document 1, it is necessary to provide an angle adjusting mechanism for this purpose. In addition to the complexity of the configuration, there is a problem that the housing of the sensor becomes large due to the mounting of these adjusting mechanisms, and this also causes an increase in cost. The same applies to the case of Patent Document 2, which requires a special configuration for switching the condensing optical system, the infrared detection element, and the circuit system at the subsequent stage of the infrared detection element, leading to an increase in cost. is there.

  Therefore, an object of the present invention is to provide a warning range adjustment method for a passive infrared sensor capable of easily adjusting a warning range without using a complicated configuration.

Therefore, the warning range adjustment method of the passive infrared sensor of the present invention,
A first infrared detecting element using a twin element;
A second infrared detecting element using a twin element;
A first condensing optical system arranged corresponding to the first infrared detection element, wherein an optical path through which heat rays from a diagonally downward direction are incident on the first infrared detection element by the first infrared detection element In addition, a plurality of Fresnel lenses that form a detection zone at the position where the optical path reaches the zone forming surface, which is the floor of the warning range or the ground, are arranged vertically and horizontally when the passive infrared sensor is viewed from the front. a first condensing optical system comprising Te,
A second condensing optical system disposed corresponding to the second infrared detection element, wherein the second infrared detection element and the second infrared detection element have an optical path through which heat rays from a diagonally downward direction enter the second infrared detection element And a second condensing optical system in which a plurality of Fresnel lenses that form a detection zone at a position where the optical path reaches the zone forming surface are arranged vertically and horizontally when the passive infrared sensor is viewed from the front. And
The first infrared detecting element and the first condensing optical system are:
When the zone formation surface is viewed from above,
Of the Fresnel lenses of the first condensing optical system, when viewed from the front, in the direction different from each other by the number of Fresnel lenses arranged in a row in the horizontal direction, each fan-shaped around the passive infrared sensor, When the first condensing optical system is viewed from the front, detection zones corresponding to the number of Fresnel lenses arranged in a row in the vertical direction are arranged in a jumping position on a straight line extending from the passive infrared sensor. Forming columns,
and,
The Fresnel lenses arranged in the same horizontal row when the first condensing optical system is viewed from the front form a detection zone at a position where the distance from the passive infrared sensor is substantially equal,
The second infrared detecting element and the second condensing optical system are:
When the zone formation surface is viewed from above,
Of the Fresnel lenses of the second condensing optical system, when viewed from the front, in the direction different from each other by the number of Fresnel lenses arranged in a row in the horizontal direction, each fan-shaped around the passive infrared sensor, When the second condensing optical system is viewed from the front, detection zones corresponding to the number of Fresnel lenses arranged in a row in the vertical direction are arranged in a jumping position on a straight line extending from the passive infrared sensor. Forming columns,
and,
The Fresnel lenses arranged in the same horizontal row when the second condensing optical system is viewed from the front form a detection zone at a position where the distance from the passive infrared sensor is substantially equal,
Furthermore,
A detection zone array formed by the first infrared detection element and the first condensing optical system, and a detection zone array formed by the second infrared detection element and the second condensing optical system are a zone. Arranged so as to cross alternately when moving around the passive infrared sensor without overlapping each other when viewed from the top,
and,
Each detection zone of each detection zone array formed by the second infrared detection element and the second light collection optical system is formed by the first infrared detection element and the first light collection optical system adjacent to each detection zone. A detection zone formed by the first infrared detection element and the first condensing optical system, which is arranged so as to be exactly between the detection zones arranged in the detection zone row. The detection zone formed by the infrared detection element and the second condensing optical system is fan-shaped as a whole when viewed from above, and is arranged in a substantially checkered pattern,
Furthermore,
These detection zone rows and detection zones are detection zones in the detection zone row adjacent to the detection zone row including the detection zone when attention is paid to a certain detection zone, and passive infrared rays from the target detection zone. An optical path from the nearest detection zone far from the sensor to the corresponding infrared detection element includes a detection zone row in which an object to be detected is formed by the first infrared detection element and the first condensing optical system; Of the detection zone and the second condensing optical system so as to cross the detection zone array alternately, the height is crossed by the detected object and not crossed by a small animal. A warning range adjustment method in a passive infrared sensor arranged in a certain manner,
The desired Fresnel lens of the first condensing optical system and / or the desired Fresnel lens of the second condensing optical system is masked with a mask member that does not transmit heat rays.

  According to the present invention, the desired Fresnel lens of the first condensing optical system and / or the desired Fresnel lens of the second condensing optical system are masked by the mask member without using a complicated mechanism as in the prior art. The warning range can be adjusted with a simple configuration of performing this, and an operation for adjusting the warning range is also easy.

  Even if a seal is used as the mask member or a resin molded product is used, even if the thickness is 1 mm or less, the masking effect can be sufficiently obtained. It has little effect.

Furthermore, in this passive infrared sensor, the first infrared detecting element and the first condensing optical system are the Fresnel lenses of the first condensing optical system when the zone forming surface is viewed from above. When viewed from the front, the first condensing optical system is viewed from the front, in the form of a fan centered on the passive infrared sensor, in different directions by the number of Fresnel lenses arranged in a row in the horizontal direction. Detection zones corresponding to the number of Fresnel lenses arranged in a row in the vertical direction form detection zone rows arranged at jumping positions on a straight line extending from the passive infrared sensor, and the first condensing optical system The Fresnel lenses arranged in the same horizontal row when viewed from the front form a detection zone at a position where the distance from the passive infrared sensor is substantially equal, and the second infrared detection element and the second condensing optics System is a zone type When the surface is viewed from above, among the Fresnel lenses of the second condensing optical system, when viewed from the front, passive infrared sensors are arranged in different directions by the number of Fresnel lenses arranged in a row in the lateral direction. The detection zones of the number of Fresnel lenses arranged in a row in the vertical direction when the second condensing optical system is viewed from the front, jump out on a straight line extending from the passive infrared sensor. The Fresnel lenses arranged in the same horizontal row when the second condensing optical system is viewed from the front are approximately the distance from the passive infrared sensor. A detection zone is formed at the same position, and further, a detection zone array formed by the first infrared detection element and the first condensing optical system, a second infrared detection element, and a second condensing optical system, Formed by The intelligent zone row is arranged so as to cross alternately when moving around the passive infrared sensor without overlapping each other when the zone forming surface is viewed from above, and the second infrared detecting element Each detection zone of each detection zone array formed by the second condensing optical system is skipped by a detection zone array formed by the first infrared detecting element and the first condensing optical system adjacent thereto. A detection zone, a second infrared detection element, and a second detection element, which are arranged so as to be exactly between the detection zones arranged, are formed by the first infrared detection element and the first condensing optical system. When the zone forming surface is viewed from above, the detection zones formed by the light collecting optical system are generally fan-shaped and arranged in a substantially checkered pattern. Further, these detection zone rows and detection zones are one When focusing on one detection zone, it corresponds to the detection zone in the detection zone row adjacent to the detection zone row including the detection zone, and from the nearest detection zone farther from the passive infrared sensor than the target detection zone. The optical path to the infrared detection element includes a detection zone array in which the object to be detected is formed by the first infrared detection element and the first condensing optical system, and the second infrared detection element and the second condensing optical system. and traversed by the object to be detected object when moving across alternately and detection zone row formed by, and since it is arranged such that a height which is not traversed by small animals, small animals and disturbance It is possible to reduce the possibility of erroneously detecting light as a human body.

  Hereinafter, embodiments of the invention will be described with reference to the drawings. First, a preferred embodiment of a sensor to which a warning range adjustment method according to the present invention is applied will be described with reference to FIG. FIG. 1 is a diagram schematically showing an outline of an example of the appearance of the sensor. FIG. 1 (a) is a perspective view, FIG. 1 (b) is a front view, S is a sensor, and 11 is a first view. 1 condensing optical system (hereinafter simply referred to as first optical system), 12 is a first infrared detecting element (hereinafter simply referred to as first element), and 21 is a second condensing optical system (hereinafter simply referred to as second optical system). ) And 22 are second infrared detection elements (hereinafter simply referred to as second elements), and Fij (where i and j are natural numbers, i = 1 to 8, and j = 1 to 3) respectively indicate Fresnel lenses. The first element 12 and the second element 22 are housed inside the sensor S, but are shown by broken lines in FIG. 1 to show the relationship with the first optical system 11 and the second optical system 21. .

  In FIG. 1, the first element 12 and the second element 22 are respectively arranged at predetermined positions inside the sensor S, and the first optical system 11, corresponding to the first element 12 and the second element 22, respectively. The second optical system 21 is disposed on the surface of the sensor S. Each of the first optical system 11 and the second optical system 21 is formed with a total of 12 Fresnel lenses, 3 (vertical direction in FIG. 1B) × 4 (horizontal direction in FIG. 1B). . That is, each of the first optical system 11 and the second optical system 21 is a condensing optical system including a Fresnel lens group. The first optical system 11 includes F11, F12, F13, F31, F32, F33, and F51. , F52, F53, F71, F72, and F73 are formed, and the second optical system 21 includes F21, F22, F23, F41, F42, F43, F61, F62, F63, F81, F82, and F83. 12 Fresnel lenses are formed.

  Next, the block configuration of the sensor S will be described with reference to FIG. As shown in FIG. 2, the sensor S includes a first optical system 11, a second optical system 21, and a first element 12 arranged corresponding to the first optical system 11, each consisting of a Fresnel lens group. A second element 22 arranged corresponding to the second optical system 21, signal processing circuits 16 and 26, and a determination unit 30 are provided.

  The signal processing circuit 16 performs a predetermined process on the output of the first element 12 and outputs a pulse signal when the output of the first element 12 is equal to or higher than a predetermined level. Amplifying circuit 13 that amplifies the output of element 12, band filter 14 that outputs only a signal of a predetermined frequency component by removing unnecessary frequency components from the output of amplifier circuit 13, and the output of band filter 14 are compared with a predetermined threshold value. The comparator circuit 15 outputs a pulse signal when there is a signal equal to or greater than the threshold value.

  The signal processing circuit 26 performs a predetermined process on the output of the second element 22 and outputs a pulse signal when the output of the second element 22 is equal to or higher than a predetermined level. An amplification circuit 23 that amplifies the output of the element 22, a band filter 24 that outputs only a signal of a predetermined frequency component by removing unnecessary frequency components from the output of the amplification circuit 23, and the output of the band filter 24 is compared with a predetermined threshold value. The comparator circuit 25 outputs a pulse signal when there is a signal equal to or greater than the threshold value.

  The determination means 30 determines that the detection logic is established when the two pulse signals from the signal processing circuit 16 and the signal processing circuit 26 are output within a predetermined time difference, and the establishment of the detection logic is predetermined. When a predetermined number of occurrences occur, it is determined that a human body has been detected, and a detection signal is output.

  In this sensor S, twin elements are used as the first element 12 and the second element 22. As is well known, twin elements are two pyroelectric elements that are differentially connected in series with opposite polarities, and output signals of positive (+) polarity pyroelectric elements and negative (−) polarity pyroelectric elements. A composite signal with the output signal of the element is output.

  As described above, the twin elements are used for the first element 12 and the second element 22 because the twin elements are resistant to background noise such as disturbance light, and there are few false alarms due to disturbance light. That is, for example, when disturbance light is incident on both of the two pyroelectric elements of the twin element, it is a well-known matter that the outputs of the two pyroelectric elements cancel each other and prevent false alarms.

  Next, a warning range formed by the sensor S will be described. First, a warning range when no adjustment is performed will be described. For convenience of explanation, some terms are defined here.

  If there is one infrared detection element and one Fresnel lens is arranged corresponding to the infrared detection element, the optical characteristics such as the focal length of the Fresnel lens, and the infrared detection element and the Fresnel lens Depending on the positional relationship, one optical path of heat rays entering the infrared detection element is determined by the Fresnel lens. And, such a position where the heat path is condensed by the Fresnel lens and the optical path incident on the infrared detection element reaches the floor surface or the ground surface of the warning area (in the present specification, these are collectively referred to as a zone forming surface). Is called a detection zone. Accordingly, since the first optical system 11 of the sensor S has twelve Fresnel lenses, twelve detection zones are formed by the first optical system 11 and the first element 12. Twelve detection zones are formed by the second element 22.

  When the zone forming surface is viewed from above, when a plurality of detection zones are formed and arranged on a straight line extending from the position of the sensor S, the plurality of detection zones constitute one detection zone row. Alternatively, this detection zone row is referred to as including these detection zones. Other terms will be explained as needed.

  Now, the Fresnel lenses of the first optical system 11 and the second optical system 21 of the sensor S are arranged so that the detection zone is formed in a fan shape obliquely downward with the sensor S as the center. Yes. FIG. 3 is a plan view of the detection zone row and detection zone by the first element 12 and the detection zone row and detection zone by the second element 22 on the zone forming surface as viewed from above.

  In FIG. 3, each rectangle shown by a broken line indicates each detection zone. In FIG. 3, two rectangles indicated by solid lines are shown in each detection zone. One solid line rectangle is a region of one pyroelectric element of the twin elements of the first element 12 or the second element 22. The other solid line rectangle is the region of the other pyroelectric element of the twin element. In addition, although the broken-line rectangle indicating each detection zone is virtual, it is illustrated for convenience of explanation.

  In FIG. 3, each detection zone is labeled with Zij (where i and j are natural numbers, i = 1 to 8, j = 1 to 3), but the detection zone Zij is shown in FIG. It is formed by the Fresnel lens Fij shown in (b). That is, for example, the detection zone Z11 is formed by the Fresnel lens F11 and the first element 12 of the first optical system 11. The same applies to other detection zones.

  In FIG. 3, the three detection zones Z11, Z12, and Z13 are formed and arranged on a straight line extending from the sensor S. Therefore, these three detection zones Z11, Z12, and Z13 constitute one detection zone row. Here, the value of i of the detection zone code constituting the detection zone sequence is set to Zi as the code of the detection zone sequence. Therefore, the detection zone row formed by the three detection zones Z11, Z12, and Z13 is Z1. The same applies to other cases. That is, in the sensor S shown in FIG. 1, one detection zone row is formed by Fresnel lenses arranged in a vertical row of the first optical system 11 and the second optical system 21.

  As described above, in the alert range shown in FIG. 3, a plurality of detection zone rows extend in a fan shape centering on the sensor S, and each detection zone row includes a plurality of detection zones. 3 is not actually formed on the zone forming surface, but is illustrated as a substantially fan-shaped frame in FIG. 3 for easy understanding. .

  By the way, when a twin element is used as the infrared detection element, the detection direction in which a moving object can be detected is a direction across the area of the negative polarity pyroelectric element from the positive polarity pyroelectric element area of the twin element in the detection zone. Or it is the direction which crosses to the contrary. In the alert range shown in FIG. 3, the areas of the two pyroelectric elements having the positive polarity and the negative polarity of the first element 12 or the second element 22 in each detection zone are substantially orthogonal to the direction in which the detection zone row extends. In other words, they are arranged in a direction crossing the detection zone row. Therefore, the detection direction of the object in the alert range shown in FIG. 3 is the direction across the detection zone row, that is, the direction moving from the lower direction to the upper direction in FIG. This detection direction is naturally set to a direction in which the object is supposed to move within the alert range or a direction in which the moving object is desired to be detected.

  In the arrangement of the detection zone row and the detection zone shown in FIG. 3, the adjacent detection zone rows are formed so as not to overlap each other, and each detection zone of the adjacent detection zone row includes different infrared detection elements and the same. And a corresponding condensing optical system. As is apparent from the above description, in FIG. 3, each detection zone of the detection zone row of Z1, Z3, Z5, and Z7 is formed by the first element 12 and the first optical system 11, and Z2, Z4, Z6, and Z8. Each detection zone of the detection zone row indicated by is formed by the second element 22 and the second optical system 21.

  As described above, in this sensor S, each detection zone in the adjacent detection zone row is formed by a different infrared detection element and a condensing optical system corresponding thereto, in other words, with respect to the detection direction. In other words, each detection zone of the detection zone array formed before and after is formed by a different infrared detection element and a corresponding condensing optical system.

  Then, the detection zones included in the detection zone rows adjacent to each other are arranged so that they are not located at the same distance when viewed from the distance from the sensor S of these detection zone rows. In other words, the detection zones included in a certain detection zone row are not arranged at the same distance from the sensor S as the detection zones included in the detection zone row adjacent thereto. That is, in FIG. 3, the detection zone row Z1 and the detection zone row Z2 are detection zone rows adjacent to each other, and the position of the distance from the sensor S in each of the detection zones Z11 and Z12 of the detection zone row Z1 is The positions of the detection zones Z21, Z22, and Z23 in the detection zone row Z2 from the distance from the sensor S are not the same, but are different. That is, the detection zones included in the detection zone rows adjacent to each other are arranged so that they are not located at the same distance when viewed from the distance from the sensor S of these detection zone rows. That is. The same applies to the arrangement of the detection zones in the other adjacent detection zone rows.

  In the example of the detection zone row and the detection zone arrangement shown in FIG. 3, the detection zone of a certain detection zone row is a position where the detection zone of the adjacent detection zone row is not formed, that is, the adjacent detection zone row. Since it is arranged so as to be just between the detection zone and the detection zone, the detection zone formed by the first optical system 11 and the first element 12, the second optical system 21, and the second element 22 It can be said that the formed detection zones are arranged in a substantially checkered pattern as a whole.

  FIG. 4 is a side view as seen from the direction of the arrow indicated by a in FIG. , Simply referred to as the optical path from the detection zone to the corresponding element. The same shall apply hereinafter in this regard.) In FIG. The optical path from each detection zone of the detection zone row Z1 to the corresponding first element 12 is shown, and the hatched area is the second element corresponding to each detection zone of the detection zone row Z2 by the second optical system 21. The optical path to 22 is shown. In FIG. 4, the sensor S is attached to the wall surface.

  Further, these detection zone rows and detection zones are detection zones in a detection zone row adjacent to a detection zone row including the detection zone when attention is paid to a certain detection zone, and the attention detection zone The optical path from the nearest detection zone farther away from the sensor S to the corresponding element is traversed by the human body that is the detected object along the detection direction, and is not traversed by the small animal. Arranged to be at height. Here, as the human body, the human body having the lowest height to be detected may be assumed, and as the small animal, the tallest small animal that is not detected may be assumed.

  However, this is not the case when the detection zone located farthest from the sensor S is the target detection zone. Because, in the case shown in FIG. 3, the detection zones indicated by Z21, Z41, Z61, and Z81 in the drawing are the detection zones that are located farthest from the sensor S, but when these detection zones are the attention detection zones, This is because there is no detection zone in the detection zone row adjacent to the detection zone row including these detection zones, and there is no nearest detection zone farther from the sensor S than the target detection zone.

  For example, the detection zone indicated by Z22 in FIG. At this time, there are two detection zone rows of Z1 and Z3 in the detection zone row adjacent to the detection zone row Z2 including the attention detection zone Z22. Then, there are two detection zones, Z11 and Z31, which are detection zones included in the detection zone row of Z1 and Z3 and are located farther from the sensor S than the target detection zone Z22.

  The optical path from the detection zone Z31 to the corresponding first element 12 is that the human body as the detected object moves in the direction of the detection zone Z31 from the attention detection zone Z22 side along the detection direction. Similarly, the optical path from the detection zone Z11 to the corresponding first element 12 is detected by the human body that is the object to be detected. When it moves in the direction of the detection zone Z11 from the attention detection zone Z22 side along the direction, it is crossed by the human body and placed at a height that is not crossed by small animals.

  The attention detection zone Z22, the optical path from the detection zone Z11 to the corresponding first element 12, the relationship between the height of the human body H and the small animal M, and the attention detection zone Z22 and the detection zone Z31 correspond to each other. The relationship between the optical path to the first element 12 and the height of the human body H and the small animal M is shown in FIG. FIG. 5A shows a detection zone row Z2 including Z22 which is the detection zone of interest, an optical path from each detection zone of the detection zone row Z1 to the first element 12, and the heights of the human body H and the small animal M in FIG. 3 is a side view seen from the direction indicated by the arrow a in FIG. 3, and is a detection zone of the detection zone row Z1 adjacent to the detection zone row Z2 including the attention detection zone Z22, The optical path R1 from Z11, which is the nearest detection zone farther from the sensor S than the attention detection zone Z22, to the first element 12 is set so as to be crossed by the human body H and not crossed by the small animal M. Has been.

  FIG. 5B shows a detection zone row Z2 including Z22 which is the detection zone of interest in FIG. 3, an optical path from each detection zone of the detection zone row Z3 to the corresponding first element 12, a human body H and a small animal M. 3 is a side view seen from the direction indicated by the arrow a in FIG. 3, and is a detection zone of the detection zone row Z3 adjacent to the detection zone row Z2 including the attention detection zone Z22. The optical path R3 from Z31, which is the nearest detection zone farther from the sensor S than the attention detection zone Z22, to the corresponding first element 12 is crossed by the human body H and is not crossed by the small animal M. It is set to be.

  Therefore, for example, if the human body H moves in the direction indicated by the arrow b in FIG. 3, the human body H first traverses the optical path from the detection zone Z11 to the first element 12, and then from the detection zone Z22 to the second element. The optical path to the first element 12 is then traversed from the detection zone Z31. However, even if the small animal M moves in the same manner, the optical path from the detection zone Z11 to the first element 12 and the optical path from the detection zone Z31 to the first element 12 do not cross.

  Although the case where the detection zone Z22 is the attention detection zone has been described above, the same applies to the case where the other detection zones are attention detection zones. However, as described above, this is not the case when attention is paid to the detection zone located farthest from the sensor S.

  The arrangement of such detection zone rows and detection zones is based on the mounting height of the sensor S and the longest detection distance to which a human body is detected, and the first optical system 11 and the second optical system 21. It can be formed by determining the focal length of each Fresnel lens Fij, the positional relationship between the first optical system 11 and the first element 12, and the positional relationship between the second optical system 21 and the second element 22.

  Now, when the detection zone row and the detection zone are arranged as described above, the position of the human body in the detection zone row Z8 from the detection zone row Z1 side along the detection direction is indicated by the arrow a in FIG. Suppose you move in the direction. At this time, when the human body first enters the position of the detection zone Z11, it crosses the optical path from the detection zone Z11 to the first element 12, so that the heat rays from the human body are detected by the first element 12, and the output thereof is the signal processing circuit. 16 is processed to output a pulse signal.

  Thereafter, the human body crosses the detection zone row Z2, but at this time, since the human body crosses the optical path from the detection zone Z21 to the second element 22, the heat rays from the human body are detected by the second element 22, and the output is A pulse signal is output after being processed by the signal processing circuit 26. If the pulse signal from the signal processing circuit 16 and the pulse signal from the signal processing circuit 26 are within a predetermined time difference, the determination unit 30 determines that the detection logic has been established.

  Accordingly, if the human body moves along the detection direction at a speed equal to or higher than the speed corresponding to the time difference that the determination means 30 determines that the detection logic is established, the optical path from the two adjacent detection zone rows to the corresponding element is changed. Each time it crosses, it is determined that the detection logic is established by the determination means 30, and when the detection logic is generated a predetermined number of times, the determination means 30 determines that a human body has been detected and outputs a detection signal.

  From the above, any position of the human body is detected when it moves along the detection direction.

  On the other hand, the operation when the small animal makes the same movement as the human body described above is as follows. When a small animal crosses directly over the detection zone on the zone forming surface, the heat rays from the small animal are detected by an element corresponding to the detection zone, and the output is processed by a corresponding signal processing circuit to generate a pulse signal. Next, when the adjacent detection zone row is crossed, the optical path from the detection zone of the detection zone row to the corresponding element does not cross, so that the heat ray from the small animal is adjacent to the adjacent detection zone row. The element corresponding to the detection zone row is not detected.

  Therefore, every time a small animal crosses two adjacent detection zone rows, there is no possibility that the determination means 30 determines that the detection logic has been established. As a result, the small animal is determined to be a human body, and the detection signal is output from the determination means 30. Is not likely to be output.

  As described above, in this sensor S, false alarms caused by small animals can be avoided by configuring the detection zone array and the detection zone arrangement as described above.

  The arrangement of the detection zone row and the detection zone described above can avoid not only erroneous notifications caused by small animals, but also avoid erroneous notifications caused by ambient light. This will be described below. By the way, the zone formation surface may be a diffusion surface on which the surface is not smooth and the reflected light from the zone formation surface is diffusely reflected, or it may be a smooth smooth surface. A case of a surface will be described.

  When the zone forming surface is a diffusion surface, even if the reflected light from the zone forming surface is incident on the first element 12 and / or the second element 22, the reflected light on the zone forming surface is not directional. Therefore, the amount of light incident on the positive polarity pyroelectric element and the negative polarity pyroelectric element of the first element 12 and / or the second element 22 is approximately the same, and the output of the positive polarity pyroelectric element and the negative polarity pyroelectric element are the same. Since the outputs of the electric elements are canceled out, the possibility that the determination means 30 determines that the detection logic has been established is very low, and therefore, the possibility of false alarm due to ambient light is very low.

  Next, the case where the zone forming surface is a smooth smooth surface will be described with reference to FIG. In FIG. 6, a thick solid line indicates incident light of disturbance light, and a thick broken line indicates reflected light from the zone forming surface.

  The arrangement of the detection zone rows and detection zones shown in FIG. 6 is the same as that shown in FIG. 3, and it is assumed that disturbance light is incident at a certain angle and a certain width from the direction indicated by the thick solid line in FIG. Then, the disturbance light incident on the region of the detection zone row Z7 is reflected at the position of one detection zone Z71 constituting the detection zone row Z7 as indicated by d, and the corresponding first as shown by the thick broken line. Assume that the light enters the element 12. At this time, the reflected light may enter one of the positive polarity pyroelectric element and the negative polarity pyroelectric element of the first element 12. In that case, detection is performed by the first element 12, and the output is processed by the signal processing circuit 16 to output a pulse signal.

  However, the disturbance light e incident on the detection zone column Z6 adjacent to the detection zone column Z7 and the disturbance light f incident on the detection zone column Z8 correspond to the reflected light at any position of these detection zone columns Z8. The possibility of entering the two elements 22 is very low. Because the reflected light on the smooth surface has a sharp directivity and concentrates in the same direction as the incident light, the reflected light from the detection zone array Z6 and the detection zone array Z8 is sensor S as shown by the thick broken lines in the figure. It will come off. Therefore, the reflected light from the detection zone arrays Z6 and Z8 does not enter the second elements 22 corresponding to these detection zone arrays, and no pulse signal is output from the signal processing circuit 26. It is very unlikely that the detection logic is established at 30.

  As described above, according to this sensor S, it is possible to significantly reduce false alarms due to disturbance light as compared with the conventional case.

  The preferred embodiments of the sensor range adjustment method according to the present invention have been described above. Next, the first embodiment of the warning range adjustment method according to the present invention will be described. First, for the convenience of the following description, the longest detection distance will be described. In the case of the detection zone arrangement shown in FIG. 3, that is, when the warning range is not adjusted, or when the detection zone Z11 is set as the attention detection zone, the detection zone row adjacent to the detection zone row including the detection zone Z11 is displayed. The detection zone that is the detection zone that is farther from the sensor S than the target detection zone is Z21, and no detection zone is formed farther from the detection zone Z21 than the sensor S. The detection distance is the farthest distance that the human body can cross the detection zone Z11.

  Here, when a heat source such as a human body crosses the entire detection zone, the level of the input signal of the comparison circuit 15 or the comparison circuit 25 in FIG. 2 exceeds the threshold set by the comparison circuit 15 or the comparison circuit 25. As described above, when the gains of the amplifier circuits 13 and 23 are set, the farthest distance from which the pulse signal is output from the comparison circuit 15 when the heat source crosses the detection zone Z11 is the lowest part of the heat source (human body In this case, the foot) crosses the position closest to the sensor S in the detection zone Z11. Therefore, in the case shown in FIG. 3, the longest detection distance is the distance indicated by L1 in FIGS.

  In the sensor S described above, the warning range is adjusted by masking the desired Fresnel lens of the first optical system 11 or the desired Fresnel lens of the second optical system 21 with a mask member. An example is shown in FIG.

  FIG. 7A shows an example in which four Fresnel lenses F11, F31, F51, and F71 arranged at the top of the Fresnel lenses of the first optical system 11 are masked by the mask member M. Here, the material of the mask member M may be any material that does not transmit heat rays, may be a seal, and is a resin molded product that is detachable from a desired Fresnel lens of the first optical system. May be. In FIG. 7, the mask member M is assumed to be a seal, and the masked Fresnel lens is hatched.

  As shown in FIG. 7A, when masking is performed by attaching a mask member M to the four Fresnel lenses F11, F31, F51, and F71 of the first optical system 11, 4 of Z11, Z31, Z51, and Z71. Since two detection zones are not formed, the longest detection distance is a distance indicated by L2 in FIGS.

  FIG. 7B shows eight Fresnel lenses F11, F12, F31, F32, F51, F52, F71, and F72 arranged in the uppermost stage and the lower stage among the Fresnel lenses of the first optical system 11. The example which masked by the mask member M is shown. In this case, since eight detection zones of Z11, Z12, Z31, Z32, Z51, Z52, Z71, and Z72 are not formed, the longest detection distance is a distance indicated by L3 in FIGS.

  FIG. 7C shows an example in which, among the Fresnel lenses of the first optical system 11, three Fresnel lenses F11, F12, and F13 arranged on the left end side are masked by the mask member M. In this case, the longest detection distance remains L1, but the three detection zones Z11, Z12, and Z13 are not formed, that is, the detection zone row Z1 in FIG. The spread angle can be narrowed. This is also one mode of adjustment of the alert range.

  As mentioned above, although three cases were explained about a mode of adjustment of a warning range, there are various modes of adjustment of a warning range besides this. For example, although the desired Fresnel lens of the first optical system 11 is masked in the example shown in FIG. 7, the desired Fresnel lens of the second optical system 21 may be masked, or the desired Fresnel lens of the first optical system 11 may be masked. The Fresnel lens and the desired Fresnel lens of the second optical system 21 can also be masked.

  For example, for the first optical system 11, four Fresnel lenses F13, F33, F53, and F73 arranged at the bottom are masked, and for the second optical system 21, F21 and F41 are arranged at the top. When the four Fresnel lenses F61 and F81 are masked, the eight detection zones Z13, Z33, Z53, Z73, Z21, Z41, Z61 and Z81 are not formed, so the longest detection distance is the distance indicated by L4 in FIG. In addition, the vicinity of the sensor S can be removed from the alert range.

  As described above, which Fresnel lens of which optical system of the first optical system 11 and the second optical system 21 is to be masked is determined in consideration of the alert range required for the location where the sensor S is installed. It's good.

  The case where the seal is used as the mask member M has been described above, but the case where a resin molded product is used as the mask member will be described with reference to FIG. In FIG. 8, the mask member M extends outside the first optical system 11 of the sensor S in the vertical direction of the sensor S indicated by the arrow in the drawing, that is, in the direction from the uppermost stage to the lowermost stage of the first optical system 11. It can slide in the opposite direction. Naturally, the mask member M is formed of a material that does not transmit heat rays.

  The longitudinal length of the mask member M has a length that can mask the two-stage Fresnel lens of the first optical system 11, and the lateral width perpendicular to the longitudinal direction is the first optical system 11. The width is sufficient to mask the four Fresnel lenses arranged side by side. The mask member M can take the following four positions on the front surface of the first optical system 11.

  The first position is a position where the Fresnel lens of the first optical system 11 is not masked as shown in FIG. That is, the first position is the uppermost position. The second position below is a position for masking the uppermost four Fresnel lenses F11, F31, F51, and F71 of the first optical system 11, as shown in FIG. As shown in FIG. 7B, the third position below the second position is F11 and F12 arranged in the uppermost stage and the lower stage among the Fresnel lenses of the first optical system 11. , F31, F32, F51, F52, F71, and F72 are masking positions for the eight Fresnel lenses. The fourth position below the third position is a position for masking eight Fresnel lenses of F12, F32, F52, F72, F13, F33, F53, and F73 arranged in the lowermost stage and the upper middle stage. is there.

  Therefore, it will be apparent from the above that the warning range can be adjusted to a desired state by adjusting the position of the mask member M in accordance with the situation of the location where the sensor S is installed. Note that the arrangement of the detection zone row and the detection zone shown in FIG. 3 is merely an example, and the present invention is not limited to this.

  As described above, according to the warning range adjustment method, the warning range can be adjusted by a simple configuration in which a seal is attached or a resin molded product is slid without using a complicated mechanism as in the past. The operation for adjusting the alert range is also easy. Even if a seal is used as the mask member or a resin molded product is used, even if the thickness is 1 mm or less, the masking effect can be sufficiently obtained. It has little effect.

It is a figure which shows the external appearance of embodiment of a suitable passive infrared sensor which applies the warning range adjustment method by this invention, FIG. 1 (a) is a perspective view, FIG.1 (b) is a front view. It is a figure which shows the block configuration of the passive infrared sensor shown in FIG. In the passive infrared sensor shown in FIG. 1, it is a figure which shows the case where a detection zone row | line | column and a detection zone are formed so that it may arrange | position so that it may be fan-shaped diagonally downward centering on a passive infrared sensor, and the infrared detection in a zone formation surface 4 is a plan view of a detection zone row and a detection zone by an element 12 and a detection zone row and a detection zone by an infrared detection element 22 as viewed from above. FIG. FIG. 4 is a side view seen from the direction of the arrow indicated by a in FIG. 3, and is a side view showing an optical path of heat rays incident on corresponding elements from the detection zones of two detection zone rows of Z1 and Z2. The attention detection zone Z22, the optical path from the detection zone Z11 to the first element 12, the relationship between the height of the human body H and the small animal M, the attention detection zone Z22, and the optical path from the detection zone Z31 to the first element 12 It is a figure which shows the relationship between the height of the human body H and the small animal M. In the arrangement of the detection zone row and the detection zone shown in FIG. 3, when the zone forming surface is a smooth surface, it is a diagram for explaining that there is a lower possibility of misreporting due to disturbance light than in the prior art. It is a figure which shows embodiment of the warning range adjustment method of the passive infrared sensor which concerns on this invention. It is a figure which shows embodiment of this invention at the time of using the resin molded product as a mask member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Condensing optical system, 12 ... Infrared detector, 13 ... Amplifier circuit, 14 ... Band pass filter, 15 ... Comparison circuit, 16 ... Signal processing circuit, 21 ... Condensing optical system, 22 ... Infrared detector, 23 ... Amplification Circuit, 24 ... band filter, 25 ... comparison circuit, 26 ... signal processing circuit, 30 ... determining means, Fij (i and j are natural numbers i = 1 to 8, j = 1 to 3) ... Fresnel lens, Zij (I and j are natural numbers, i = 1 to 8, j = 1 to 3)... Detection zone, M.

Claims (1)

A first infrared detecting element using a twin element;
A second infrared detecting element using a twin element;
A first condensing optical system arranged corresponding to the first infrared detection element, wherein an optical path through which heat rays from a diagonally downward direction are incident on the first infrared detection element by the first infrared detection element In addition, a plurality of Fresnel lenses that form a detection zone at the position where the optical path reaches the zone forming surface, which is the floor of the warning range or the ground, are arranged vertically and horizontally when the passive infrared sensor is viewed from the front. a first condensing optical system comprising Te,
A second condensing optical system disposed corresponding to the second infrared detection element, wherein the second infrared detection element and the second infrared detection element have an optical path through which heat rays from a diagonally downward direction enter the second infrared detection element And a second condensing optical system in which a plurality of Fresnel lenses that form a detection zone at a position where the optical path reaches the zone forming surface are arranged vertically and horizontally when the passive infrared sensor is viewed from the front. And
The first infrared detecting element and the first condensing optical system are:
When the zone formation surface is viewed from above,
Of the Fresnel lenses of the first condensing optical system, when viewed from the front, in the direction different from each other by the number of Fresnel lenses arranged in a row in the horizontal direction, each fan-shaped around the passive infrared sensor, When the first condensing optical system is viewed from the front, detection zones corresponding to the number of Fresnel lenses arranged in a row in the vertical direction are arranged in a jumping position on a straight line extending from the passive infrared sensor. Forming columns,
and,
The Fresnel lenses arranged in the same horizontal row when the first condensing optical system is viewed from the front form a detection zone at a position where the distance from the passive infrared sensor is substantially equal,
The second infrared detecting element and the second condensing optical system are:
When the zone formation surface is viewed from above,
Of the Fresnel lenses of the second condensing optical system, when viewed from the front, in the direction different from each other by the number of Fresnel lenses arranged in a row in the horizontal direction, each fan-shaped around the passive infrared sensor, When the second condensing optical system is viewed from the front, detection zones corresponding to the number of Fresnel lenses arranged in a row in the vertical direction are arranged in a jumping position on a straight line extending from the passive infrared sensor. Forming columns,
and,
The Fresnel lenses arranged in the same horizontal row when the second condensing optical system is viewed from the front form a detection zone at a position where the distance from the passive infrared sensor is substantially equal,
Furthermore,
A detection zone array formed by the first infrared detection element and the first condensing optical system, and a detection zone array formed by the second infrared detection element and the second condensing optical system are a zone. Arranged so as to cross alternately when moving around the passive infrared sensor without overlapping each other when viewed from the top,
and,
Each detection zone of each detection zone array formed by the second infrared detection element and the second light collection optical system is formed by the first infrared detection element and the first light collection optical system adjacent to each detection zone. A detection zone formed by the first infrared detection element and the first condensing optical system, which is arranged so as to be exactly between the detection zones arranged in the detection zone row. The detection zone formed by the infrared detection element and the second condensing optical system is fan-shaped as a whole when viewed from above, and is arranged in a substantially checkered pattern,
Furthermore,
These detection zone rows and detection zones are detection zones in the detection zone row adjacent to the detection zone row including the detection zone when attention is paid to a certain detection zone, and passive infrared rays from the target detection zone. An optical path from the nearest detection zone far from the sensor to the corresponding infrared detection element includes a detection zone row in which an object to be detected is formed by the first infrared detection element and the first condensing optical system; Of the detection zone and the second condensing optical system so as to cross the detection zone array alternately, the height is crossed by the detected object and not crossed by a small animal. A warning range adjustment method in a passive infrared sensor arranged in a certain manner,
Adjusting the warning range of a passive infrared sensor, wherein a desired Fresnel lens of the first condensing optical system and / or a desired Fresnel lens of the second condensing optical system is masked by a mask member that does not transmit heat rays. Method.

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