JPH11281476A - Infrared ray sensor and monitoring device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lengthen the service life, to facilitate maintenance/inspection, and to improve monitoring accuracy by constituting a pyroelectric element of a light receiving electrode plate for monitoring a two-dimensional scanning monitoring area formed by unfolding an one-dimensional monitoring area by being continuously arranged in a light receiving electride row for monitoring the one-dimensional monitoring area. SOLUTION: A circular pyroelectric element E mounted on a printed circuit board of an infrared ray sensor is constituted of a light receiving electrode row L1 for monitoring an one-dimensional monitoring area and a light receiving electrode plate L2 having the slightly large light receiving surface expanding in the lateral direction and monitoring a two-dimensional scanning monitoring area formed by unfolding the one-dimensional monitoring area together with the light receiving electrode row L1 by juxtaposing plural light receiving electrodes E1 to E8 in a row. The light receiving electrodes E1 to E8 are a square shape, and constitute the light receiving electrode row L1 by one channel (CH) to 8 CH, and the light receiving electrode plate L2 is constituted of almost semicircular light receiving electrodes Ea, Eb to be continuously arranged on both sides by sandwiching the light receiving electrode row L1 . Therefore, when a fire is caused in the two-dimensional scanning monitoring area, the pyroelectric element E judges the occurrence of the fire by receiving infrared rays.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared sensor using a pyroelectric element for detecting a fire that has occurred in a medium- or large-scale space and the position of a fire source, and a monitoring device using the same.

[0002]

2. Description of the Related Art FIG. 9 is an explanatory view showing the configuration of a conventional monitoring device using a pyroelectric element, and shows the device described in Japanese Patent Publication No. 5-46599. In FIG. 9, 11 is a detection unit, 12 is a turning unit, 14 is a base, 16 is an optical system, and 17 is a detection element using a pyroelectric body. Reference numeral 20 denotes a vertical detection range, 20a denotes an instantaneous visual field, 21 denotes a motor, 22 denotes a rotating mirror, 23 denotes an objective lens, 24 denotes a reflecting mirror, 25 denotes a slit, 26 denotes a condenser lens, and 27 denotes a rotary unit. As shown in FIG. 9, the turning unit 12 is arranged on the base 14 so as to be able to turn in the horizontal direction, and the detecting unit 11 for detecting a fire is arranged on the turning unit 12. And
The monitoring device is installed in a place where a monitoring surface such as an indoor stadium having a wide space can be monitored from obliquely above.

The operation of the conventional monitoring device having such a configuration will be described below. The optical image of the instantaneous visual field 20 a within the vertical detection range 20 of the monitoring surface is converted into an optical system 16 such as an objective lens 23.
And is incident on the detection element 17 through the. Then, the rotating mirror 2 is driven by the motor 21 in the detecting unit 11.
2 is driven to scan the vertical detection range 20 on the monitoring surface from top to bottom, thereby performing vertical scanning. On the other hand, in synchronization with the rotation of the rotating mirror 22 of the detection unit 11 in the above vertical scanning,
The motor of the turning unit 12 is driven by the control signal, and the rotary unit 27 is stepped and controlled to perform horizontal scanning while reciprocating between the origin and a fixed point.

[0004]

The monitoring device using the conventional pyroelectric element described in the above-mentioned publication performs vertical scanning by rotating the rotating mirror 22 and the reflecting mirror 24 with the motor 21 as described above. The revolving unit 12 in which the structure for vertical scanning is integrated
Is rotated on the base 14 to perform horizontal scanning. Accordingly, the movable parts such as the rotating shaft of the rotary unit 27 and the belt for transmitting torque are deteriorated due to wear, so that the monitoring performance is reduced, and the maintenance and management of the equipment installed at a high place becomes troublesome. There were drawbacks. Further, in the worst case, there is a problem that the continuous monitoring state cannot be maintained due to breakage of the movable portion, and the monitoring becomes impossible.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional infrared sensor using a pyroelectric element, and reduces the failure rate by scanning a monitoring area in which movable parts are eliminated as much as possible. It is an object of the present invention to realize an infrared sensor using a pyroelectric element which is easy to maintain and inspect, is economical, and has high monitoring accuracy, and a monitoring device for the infrared sensor.

[0006]

According to the present invention, there is provided a light-receiving electrode array comprising a plurality of light-receiving electrodes for monitoring a one-dimensional monitoring area, and a one-dimensional monitor provided with and connected to the light-receiving electrode array. An infrared sensor using a pyroelectric element provided with a pyroelectric element comprising a light receiving electrode plate for monitoring a two-dimensional scanning monitoring area formed by expanding the area. Further, according to the invention of claim 1, an infrared sensor using a pyroelectric element in which the length of the array of light-receiving electrodes on the apogee side in the light-receiving electrode array is shorter than the light-receiving electrode on the perigee side. Further, in the invention of claim 1 or 2, a pyroelectric element is used in which two light receiving electrode rows are provided, and the light receiving electrodes of one light receiving electrode row are arranged at positions where the gaps between the light receiving electrodes of the other light receiving electrode row are filled. Of the infrared sensor.

Further, the present invention provides a pyroelectric element in which a light receiving electrode array and a light receiving electrode plate are formed on a pyroelectric body, and a switching plate in which a monitoring window for the light receiving electrode array and the light receiving electrode plate of the pyroelectric element is formed. An infrared sensor consisting of a collimator for switching and a chopper rotating a sector plate for chopping the incident light of the light receiving electrode array. Lines generated in the two-dimensional scanning monitoring area by the light receiving electrode array and the light receiving electrode plate in the infrared sensor. A monitoring device is configured to detect infrared rays emitted by the source and scan the light receiving electrode array into a two-dimensional scanning monitoring area to detect the position of the radiation source.

After the power is turned on, the monitoring mode is set to the constant monitoring mode after an abnormality of the monitoring device is checked. When the continuous monitoring mode is set, the small-diameter portion of the chopper stops at the front of the pyroelectric element, and the monitoring window of the collimator faces the pyroelectric element, and both the light receiving electrode array and the front surface of the light receiving electrode plate are opened to focus. The monitoring of the electronic elements is enabled. Thereafter, when a fire occurs in the scanning monitoring area, the pyroelectric element receives infrared rays and the occurrence of the fire is determined. The monitoring mode is switched to the fire source position detection mode based on the determination result of the fire occurrence.

When the monitoring mode is switched to the fire source position detection mode, the motor is driven to rotate the collimator, and the rectangular monitoring window on the switching disk stops facing the light receiving electrode array. The sector disk is rotated by the motor of the chopper, and the chopping of the incident light of each light receiving electrode is started by the alternate rotation of the small diameter portion and the large diameter portion. In this way, an optical signal synchronized with the rotation of the chopper is incident on the light receiving electrode array via the optical system. After the optical signal incident on the light receiving electrode array is received by the plurality of light receiving electrodes and converted into an electric signal, a pulse signal corresponding to the temperature of the fire source is output from the light receiving electrode array. On the other hand, the monitoring device is turning while reciprocating on the turning axis, and the encoder outputs a pulse signal according to the turning angle.

As a result, the position of the fire source in the scanning monitoring area is determined from the turning angle output by the encoder corresponding to the maximum output of the plurality of light receiving electrodes in the light receiving electrode array. The result of the determination is displayed on a display unit of the monitoring device, a fire receiver, or the like, and at the same time, an operation signal for operating the fire extinguishing equipment installed near the position of the fire source is output. According to the present invention having such a configuration, in the constant monitoring mode, the driving operation of the monitoring device becomes unnecessary, and a stable monitoring operation without abrasion or damage of the movable portion unlike the conventional device occurs. To be continued.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. 1 is a bottom view of a main part of the first embodiment of the present invention, FIG. 2 is a side view of the first embodiment, FIG. 3 is an enlarged plan view of the pyroelectric element, and FIG. 4 is a cross-sectional view taken along line XX of FIG. . In FIGS. 1 to 4, S is an infrared sensor. E is a circular pyroelectric element mounted on a printed circuit board, L1 is a light-receiving electrode array in which a plurality of light-receiving electrodes E1, E2,... (Described in FIG. 4) are arranged in a line, and L2 is expanded in the horizontal direction. This is a light receiving electrode plate having a slightly large light receiving surface. Each light receiving electrode E1, E2 ...
Is a rectangular shape, and a light receiving electrode row L1 is composed of 1 channel (hereinafter, CH) to 8CH. The light receiving electrode plate L2 is composed of two substantially semicircular light receiving electrodes Ea and Eb, and is continuously provided on both sides of the light receiving electrode row L1.

10 is a collimator, 40 is a chopper, 1
Motors 1 and 41 drive the collimator 10 and the chopper 40, respectively. The collimator 10 switches the monitoring mode, and the chopper 40 chops the incident infrared light generated at the time of fire. Reference numeral 12 denotes a switching disk provided with monitoring windows 13 and 14, and reference numeral 42 denotes a small-diameter portion 43 and a large-diameter portion 44.
It is a sector disk formed with. The rectangular monitoring window 13 provided on the switching disk 12 is used for position detection, and the circular monitoring window 14 is used for constant monitoring. 31 is a condenser lens and 32 is a stop. Although one lens 31 is shown, a combination lens is configured as needed.

FIG. 4 shows a structure of the pyroelectric element E shown in FIG. In FIG. 4, reference numeral 1 denotes a pyroelectric body. For the pyroelectric body 1, a polymer material having a spontaneous polarization, a ceramic material, or the like is used. Generally, when electrodes are attached to both surfaces of the plate-like pyroelectric body 1, a potential difference corresponding to the amount of received light is generated between the two electrodes due to a temperature change. If the material of the pyroelectric body 1 is given, PZT. Lithium tantalate. Lead titanate. P
VDF and its copolymer are formed into a thin film. Reference numeral 2 denotes a light-receiving electrode constituting the above-described light-receiving electrode row L1, reference numeral 3 denotes a base electrode, and reference numeral 4 denotes a printed board. 5
Is a detection circuit, and 6 is a lead wire for derivation. Pyroelectric element E
Are sandwiched on the printed circuit board 4 with the light-receiving electrode 2 as the front side, and are connected to the detection circuit 5 by a lead wire 6 for lead-out.

FIG. 5 is an explanatory diagram showing an installation state of the monitoring device according to the first embodiment. In FIG. 5, reference numeral D denotes a monitoring device, in which an infrared sensor S using the above-described pyroelectric element E is incorporated. Reference numeral 7 denotes a rotating shaft, 8 denotes a gear train, and 9 denotes an encoder. The monitoring device D is driven by an electric motor (not shown) to reciprocate in a predetermined angular range while turning on the turning shaft 7, and the encoder 9 outputs a pulse signal corresponding to the turning angle of the turning shaft 7. θ is a projection angle when the arrangement direction of the light receiving electrode array L1 is enlarged and projected into the monitoring area, and θ1, θ2,... are projection angles of the light receiving electrodes E1, E2,.

A1, a2,... Are light-receiving electrodes E1, E
.., A1 is a one-dimensional monitoring area formed by a projected image of the light-receiving electrode row L1, and A2 is a one-dimensional one by displacing the light-receiving electrode row L1 in a direction intersecting the arrangement direction. A two-dimensional scanning monitoring area developed from monitoring area A1, A
Is a monitoring area that occupies the entire space inside a gymnasium or theater (A2 is not shown). The one-dimensional monitoring area A1 corresponds to the vertical detection range 20 shown in the description of the conventional example, and the section monitoring areas a1, a2,... Correspond to the instantaneous visual field 20a.

The monitoring operation of the first embodiment having such a configuration will be described below with reference to the flowchart of FIG. The main monitoring operation of the embodiment of the present invention is the continuous monitoring mode M.
1 and a fire source position detection mode M2.
First, after energization, the presence or absence of an abnormality in the monitoring device D is checked, and then initialization is performed. The initial monitoring mode M1 is a mode in which the motors 11 and 41 provided in the infrared sensor S are used.
Is performed by controlling the rotation angle. When the constant monitoring mode M1 is set, the motor 41 for rotating the chopper 40 is controlled, and the small-diameter portion 43 of the sector disk 42 is moved to the pyroelectric element E.
Stop at the front of.

The circular monitoring window 14 of the collimator 10
Faces the pyroelectric element E, the front surfaces of the light-receiving electrode row L1 and the light-receiving electrode plate L2 are both opened, and the pyroelectric element E is set in a state in which the two-dimensional scanning monitoring area A2 can be monitored. The light receiving electrode row L1 and the light receiving electrode plate L2 are connected to the detection circuit 5,
60d with a peak at 8Hz, the same level as a normal flame detector
An electric circuit having an amplification sensitivity of B or more is configured. Therefore, when a fire occurs in the two-dimensional scanning monitoring area A2, the pyroelectric element E receives infrared rays exceeding the threshold, and the occurrence of the fire is determined.

When it is determined that a fire has occurred in the two-dimensional scanning monitoring area A2, the monitoring mode is switched to the fire source position detection mode M2. When the monitoring mode is switched to the fire source position detection mode M2, the motor 11 is driven to rotate the collimator 10 by approximately 1/2, and the rectangular monitoring window 13 on the switching disk 12 faces the light receiving electrode row L1. And stop. Further, the sector disk 42 is rotated by the motor 41 of the chopper 40, and the infrared rays incident on the respective light receiving electrodes E1, E2,... Are chopped by the alternate rotation of the small diameter portion 43 and the large diameter portion 44.

Thus, the optical system 51 is connected to the light receiving electrode row L1.
, An optical signal synchronized with the rotation of the chopper 40 is projected. The light signal projected on the light receiving electrode array L1 is received by the light receiving electrodes E1, E2,... And converted into an electric signal, and a pulse signal corresponding to the temperature of the fire source is generated.
Will be output. On the other hand, as described above, the monitoring device D is turning while reciprocating on the turning shaft 7, and the encoder 9 outputs a pulse signal according to the turning angle.

As a result, the light receiving electrodes E in the light receiving electrode row L1
The position of the fire source in the two-dimensional scanning monitoring area A2 is determined from the turning angle of the encoder 9 corresponding to the maximum output of 1, E2. The determination result is displayed on a display unit (not shown) of the monitoring device D, a fire receiver, or the like, and at the same time, an operation signal for operating the fire extinguishing equipment installed near the position of the fire source is output. According to the first embodiment having such a configuration, in the constant monitoring mode M1, the driving operation of the monitoring device D is unnecessary, and a stable monitoring operation without abrasion or damage of the movable portion unlike the related art is performed. Can continue.

Embodiment 2 FIG. As described above, this type of monitoring device D is configured to receive the infrared rays projected from the far point to the near point in the one-dimensional monitoring area A1 by the light receiving electrodes E1, E2... In the light receiving electrode row L1. Have been.
However, if the length X in the arrangement direction of the light receiving electrodes E1, E2,... Is configured to be uniform (see FIG. 3), the projection image at the apogee becomes longer as shown by the section monitoring area a8 in FIG. Will decrease.

On the other hand, a pyroelectric element E (E is a generic name) having a structure in which electrodes are formed on both surfaces of the pyroelectric body 1 as shown in FIG. 4 can be regarded as having the same electrical characteristics as a capacitor. it can. Therefore, the light receiving area of the pyroelectric element and the amount of charge accumulated between the electrodes have an inversely proportional relationship. Therefore, when the light receiving area of the pyroelectric element E is increased, the amount of charge between the electrodes tends to increase, and the occurrence of noise tends to decrease. Conversely, when the light receiving area of the pyroelectric element E decreases, the charge amount decreases, the output fluctuates greatly, and the noise amount also increases.

Therefore, in Embodiment 2 of FIG. 7, the length X of the apogee side of the light receiving electrodes E1, E2... In the light receiving electrode row L1 is sequentially reduced, and the light receiving areas of all the light receiving electrodes E1, E2. It is configured. That is, the light receiving electrodes E1,
The vertical (arrangement direction) and horizontal size of E2.
, And Y1, Y2,..., The length X and the light receiving area (X × Y) of the light receiving electrodes E1 to E8 shown in FIG. It can be expressed by an equation. X1>X2>...> X8 (a) (X1 × Y1) = (X2 × Y2) =... = (X8 × Y8) (b) According to the second embodiment having such a configuration, the resolution It is possible to prevent the deterioration and reduce the amount of noise, thereby improving the monitoring accuracy.

Embodiment 3 FIG. FIG. 8 is a plan view of a pyroelectric element according to Embodiment 3 of the present invention. 8, g is a gap formed between the pyroelectric elements E1, E2,... In the light receiving electrode row L, and G (indicated by a line in FIG. 5) corresponds to the gap g on the projected image. This is a blind spot that cannot be monitored.
The blind area G that cannot be monitored is described as a “vertical non-monitoring area” in the above-mentioned publication.

In the third embodiment, the light receiving electrode row L of the second embodiment
A pyroelectric element E is constituted by arranging two light receiving electrode rows L11 and L12 having the same structure as that of FIG. The two light receiving electrode rows L11 and L12 are arranged so that their arrangement directions are shifted, and the left and right light receiving electrode rows L11 and L12 are arranged so as to close the gap G between each other. According to the third embodiment having such a pyroelectric element E, in addition to the effect of improving the resolution at the apogee obtained in the second embodiment, in addition to the effects of the light receiving electrode arrays L11 and L12 corresponding to the gap g described above. The blind spot area G formed in each section monitoring area a1, a2,... Formed by the projected image can be removed.

In the above-described embodiment of the present invention, the case where the common connection is made with a single base electrode has been described as an example.
It is also possible to configure a separate type in which the base electrode is separated corresponding to each light receiving electrode on the upper side. In addition, although the case where the infrared sensor is turned and deployed in a fan-shaped two-dimensional scanning monitoring area has been described, the infrared sensor is translated and rotated around a square, rectangle, or rotation axis to form a circular or annular two-dimensional scanning monitoring area. It may be developed in a dimensional scanning monitoring area. Further, the case where the fire source is monitored using the case where the light receiving electrode array has eight channels has been described. However, the number of channels may be appropriately increased or decreased to monitor a moving object or the like in the monitoring area. Is not necessarily limited to the embodiment.

[0027]

According to the present invention, a one-dimensional monitoring area is developed with a plurality of light-receiving electrodes for monitoring a one-dimensional monitoring area, and a plurality of light-receiving electrodes connected to the light-receiving electrode row. An infrared sensor using a pyroelectric element provided with a pyroelectric element comprising a light receiving electrode plate for monitoring a two-dimensional scanning monitoring area formed as described above. As a result, an infrared sensor that can receive infrared rays from a wide monitoring area two-dimensionally developed by a single sensor can be realized. Further, in the invention of claim 1, an infrared sensor using a pyroelectric element in which the length in the arrangement direction of the light-receiving electrodes on the apogee side in the light-receiving electrode row is shorter than the light-receiving electrodes on the perigee side is configured. As a result, it is possible to realize an infrared sensor with a small amount of noise without a decrease in resolution even at a distant place. Further, in the invention of claim 1 or 2, a pyroelectric element is used in which two light receiving electrode rows are provided, and the light receiving electrodes of one light receiving electrode row are arranged at positions where the gaps between the light receiving electrodes of the other light receiving electrode row are filled. The infrared sensor was configured. As a result, the gap between the light receiving electrode rows is compensated, and an infrared sensor having no unmonitored area can be provided.

Further, the present invention provides a pyroelectric element having a light receiving electrode array and a light receiving electrode plate formed on a pyroelectric body, and a switching plate having a monitoring window formed between the light receiving electrode array and the light receiving electrode plate of the pyroelectric element. An infrared sensor consisting of a collimator for switching and a chopper rotating a sector plate for chopping the incident light of the light receiving electrode array. Lines generated in a two-dimensional scanning monitoring area by the light receiving electrode array and the light receiving electrode plate in the infrared sensor. A monitoring device for detecting the position of the radiation source by detecting the infrared radiation emitted from the source and scanning the light receiving electrode array into the two-dimensional scanning monitoring area. As a result, it is possible to realize an economical monitoring device that has few movable parts, does not cause a failure due to friction or wear, and has low power consumption.

Therefore, according to the present invention, there is provided an infrared sensor using a pyroelectric element which eliminates movable parts as much as possible, has few failures, has a long service life, is easy to maintain and inspect, is economical, and has high monitoring accuracy. The monitoring device can be provided.

[Brief description of the drawings]

FIG. 1 is a bottom view of a main part according to a first embodiment of the present invention.

FIG. 2 is a side view of the first embodiment.

FIG. 3 is an enlarged plan view of the pyroelectric element of the first embodiment.

FIG. 4 is a sectional view taken along line XX of FIG. 3;

FIG. 5 is an explanatory diagram illustrating an installation state of the monitoring device according to the first embodiment.

FIG. 6 is a flowchart of a monitoring operation according to the first embodiment.

FIG. 7 is a plan view showing a configuration of Embodiment 2 of the present invention.

FIG. 8 is a plan view showing a configuration of Embodiment 3 of the present invention.

FIG. 9 is an explanatory diagram of a configuration of a monitoring device using a conventional pyroelectric element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pyroelectric body 2 (E) Light receiving electrode 3 Base electrode 4 Printed circuit board 5 Detection circuit 6 Lead wire 7 Rotating shaft 8 Gear train 9 Encoder 10 Collimator 11 Motor 12 Switching disk 13, 14 Monitoring window 40 Chopper 41 Motor 42 sector circle Plate 43 Small-diameter portion 44 Large-diameter portion 31 Condensing lens 32 Aperture a Section monitoring area A1 One-dimensional monitoring area A2 Two-dimensional scanning monitoring area A Monitoring area CH channel D Monitoring device E Pyroelectric elements E1, E2 ... Light receiving Electrodes Ea, Eb Light receiving electrode g Gap between light receiving electrode rows G Dead area L1 Light receiving electrode row L2 Light receiving electrode plate L2 Light receiving electrode plate M1 Continuous monitoring mode M2 Fire source position detection mode S Infrared sensor X Light receiving electrode length Y Light receiving electrode Width θ Projection angle of the light-receiving electrode row θ1, θ2 ...

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 37/02 H04N 7/18 N H04N 7/18 G01V 9/04 T // H01L 27/14 H01L 27/14 K

Claims (4)

[Claims] 1. A light receiving electrode array comprising a plurality of light receiving electrodes for monitoring a one-dimensional monitoring area, and the one-dimensional monitoring area is developed together with the light receiving electrode row and connected to the light receiving electrode row. An infrared sensor using a pyroelectric element, comprising: a pyroelectric element comprising a light-receiving electrode plate for monitoring a formed two-dimensional scanning monitoring area. 2. An infrared sensor using a pyroelectric element according to claim 1, wherein the length of the array of the light-receiving electrodes on the apogee side in the light-receiving electrode row is shorter than the length of the light-receiving electrodes on the perigee side. 3. The light receiving electrode array of claim 2, wherein two light receiving electrode arrays are provided, and the light receiving electrodes of one of the light receiving electrode arrays are arranged at positions where the gaps between the light receiving electrodes of the other light receiving electrode array are filled. An infrared sensor using the pyroelectric element described in the above. 4. A pyroelectric element having a light receiving electrode array and a light receiving electrode plate formed on a pyroelectric body, and a collimator for switching a switching plate having a monitoring window formed between the light receiving electrode array and the light receiving electrode plate of the pyroelectric element. An infrared sensor comprising a chopper for rotating a sector plate for chopping the incident light of the light receiving electrode array, and a line generated in a two-dimensional scanning monitoring area by the light receiving electrode array and the light receiving electrode plate in the infrared sensor. A monitoring device for detecting infrared rays emitted by a source and scanning the light receiving electrode array in a two-dimensional scanning monitoring area to detect the position of the radiation source.