JPH11296756A - Detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a detector which is free from erroneous operation without maintenance for a long time and performs stable detection operation by a simple constitution. SOLUTION: A detector 10 includes a reflection member 12 arranged on the front face of an opening/closing member 11, a light emission part 20 which throws infrared pulse light to the reflection member 12 in the close position of the opening/closing member 12, a light reception part 30 which receives reflected light of the infrared pulse light, and a control part 40 which outputs a detection signal based on the detection signal from the light reception part 30 at the time when it is lower than a prescribed trigger level. In this case, the control part 40 compares a light reception level E3 of the detection signal from the light reception part 30 with a reference level E1 and sets the trigger level based on the difference between them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detecting device for detecting opening / closing of a shutter, a door, a window and the like.

[0002]

2. Description of the Related Art Conventionally, such a detecting device has a near infrared ray with respect to a detecting surface on which a reflective sheet or the like is stuck at a predetermined position on an inner surface of a shutter for closing an entrance or exit of a store or the like or a show window. By irradiating light and detecting the amount of reflected light from the detection surface with a light receiving element, an alarm signal is output when the change in the amount of light exceeds a certain level. That is, when the shutter is closed, light reflected from the detection surface enters the light receiving element, and when the shutter is opened, light reflected not from the detection surface but from the surface of the shutter enters the light receiving element. That means
Due to the difference in reflectance between the detection surface and the shutter surface,
The amount of reflected light incident on the light receiving element decreases. An alarm signal is output based on this light amount difference.

In the detection device having such a configuration, the light receiving level of the light receiving element when the shutter is closed (at the time of caution) gradually decreases as the device is used, as indicated by reference numeral L0 in FIG. This is because dust and dirt adhere to the detection surface and become contaminated, thereby increasing absorption and scattering of near-infrared light applied to the detection surface, thereby reducing the amount of reflected light from the detection surface. Because. On the other hand, the trigger level Lt for detecting the opening of the shutter by the detection device is fixed, so that the light receiving level L0 is higher than the trigger level Lt by the gain adjustment of an amplifier for amplifying the light receiving level L0 of the light receiving element. The setting is performed so that the light receiving level L2 when the shutter is opened (at the time of an alarm) is lower than the trigger level Lt.

[0004]

However, in the detection device having such a configuration, if the contamination on the detection surface progresses with the elapse of time, the light reception level L0 of the light receiving element will further decrease, and the detection by the wind will occur. The light receiving level L0 may be lower than the trigger level Lt due to rattling of the shutter, flying insects, or the like, and a malfunction may occur. If the detection surface is further stained, the detection surface is always in an alarm state when the light receiving level L0 becomes equal to or lower than the trigger level Lt. Therefore, the detection surface needs to be cleaned. Here, if the light receiving level L0 is simply made higher than the alert level L1 by adjusting the amplifier gain or the like without cleaning the detection surface, the light receiving level L2 when the shutter is opened approaches the trigger level Lt. This increases the possibility of unreporting. Therefore, since the trigger level Lt is fixed, regarding the contamination of the detection surface, a decrease in the light reception level due to the contamination is a passive measure of performing maintenance on the detection surface in the event of an alarm due to malfunction. There was a problem.

[0005] On the other hand, a beam sensor capable of adjusting the trigger level Lt is commercially available.
In this case, the trigger level Lt is adjusted only in two steps, and it is impossible to appropriately adjust the trigger level Lt with the progress of dirt. Can not. In addition, the operation of switching the trigger level Lt needs to be performed manually, and also in this case, there is a problem that maintenance is required.

In the open / close identification sensor disclosed in, for example, Japanese Patent Laid-Open No. 5-197888, two reflecting surfaces having different reflectivities are provided on a shutter, and reflected light from these two detecting surfaces is reflected by two shutters. The opening of the shutter is detected by receiving the light by the light receiving unit and comparing the difference between the light receiving amounts of the two light receiving units with a predetermined threshold value. In this case, since two light receiving units and two reflecting surfaces are necessary, the entire device is increased in size, and it is necessary to equalize the sensitivity of the two light receiving units, and adjustment at the time of shipping is troublesome. . In addition, since there is no function to set the trigger level between the time when the shutter is opened and the time when the shutter is closed, when the light receiving level of the light receiving unit is reduced due to dirt, malfunction due to wind of the shutter or flying insects, etc. And the service life is short.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a detecting device which has a simple configuration and performs a stable detecting operation without malfunction for a long period of time without maintenance.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to an infrared light emitting device, comprising: a reflecting member provided on a surface of an opening / closing member such as a shutter; A light emitting unit for irradiating pulse light, a light receiving unit for receiving reflected light of the infrared pulse light, and a control unit for outputting a detection signal when the trigger level becomes lower than a predetermined trigger level based on a detection signal from the light receiving unit. In the detection device including the detection device, the control unit compares the light reception level of the detection signal from the light reception unit with a reference level and sets a trigger level based on the difference. In the detection device according to the present invention, preferably, the control section outputs a signal indicating that detection is not possible when the set trigger level falls below a predetermined value. The detection device according to the present invention preferably includes an alarm unit that outputs an alarm signal to the outside based on the detection signal from the control unit. The detection device according to the present invention preferably includes an amplification unit that amplifies the detection signal from the light receiving unit, adjusts the gain, and outputs the result to the control unit.

According to the above configuration, it is assumed that the light receiving level of the detection signal from the light receiving section is reduced due to the contamination of the reflecting member by dust, dirt, and the like, and the absorption and scattering of the pulse light from the light emitting section due to the contamination. Also, the control unit automatically corrects the trigger level based on the light receiving level of the detection signal from the light receiving unit, and the trigger level corresponding to the light receiving level is set. Therefore, even if the light receiving level is reduced due to dirt such as dust and dirt, the trigger level is appropriately adjusted in accordance with the lowered light receiving level. Malfunction when the light receiving level fluctuates is reduced.

Further, for example, by providing a filter having a characteristic of transmitting infrared light and absorbing visible light in the light receiving section,
Since the visible light component of the disturbance light is easily removed, malfunctions are reduced.

When the control unit outputs a signal that cannot be detected when the set trigger level falls below a predetermined value, the control unit automatically corrects the trigger level to cope with a decrease in the light receiving level of the light receiving unit. When it is not possible to perform cleaning or the like of the reflecting member, a warning display or the like can be performed by the above-mentioned undetectable signal, so that it is possible to easily grasp that maintenance is necessary.

In the case where an alarm section for outputting an alarm signal to the outside based on the detection signal from the control section is provided,
Based on the alarm signal from the alarm unit, the detection of the opening of the opening / closing member can be widely notified by generating an alarm sound, displaying an alarm, or turning on an alarm lamp.

When an amplifying unit is provided which amplifies the detection signal from the light receiving unit, adjusts the gain, and outputs the signal to the control unit, the gain adjustment facilitates the adjustment at the time of installation of the detector. It is.

When a memory, preferably an EEPROM, for storing the trigger level set by the control unit is provided, even if the power supply to the detecting device is temporarily interrupted due to, for example, a power failure, the setting by the control unit is performed. Since the set trigger level is stored in the EEPROM, it is possible to easily return to the state before the power failure or the like by reading the trigger level from the EEPROM at the time of restart.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1 shows an embodiment of the detection device according to the present invention. In FIG. 1, a detection device 10 is for detecting opening and closing of a shutter, and includes a light emitting unit 20 that irradiates an infrared pulse light to a reflection sheet 12 as a reflection member attached to the surface of the shutter 11. , Light receiving unit 30, control unit 40, power supply unit 5
0 is included.

The reflection sheet 12 is a reflection sheet having a known structure for retroreflecting incident light.
Is attached to a predetermined position on the surface of the shutter by sticking or the like in a closed state.

The light emitting section 20 emits an infrared light emitting element 21 such as an infrared LED so as to irradiate near-infrared pulse light toward the position of the reflection sheet 12 with the shutter 11 closed.
A light projecting circuit 22 for pulse-driving the infrared light emitting element 21 with a constant current, and an optical system 23 disposed in front of the infrared light emitting element 21. The light projecting circuit 22 will be described later. The infrared light emitting element 21 emits pulses at predetermined intervals by being driven and controlled by the control unit 40. Here, the optical system 23 is a condensing optical system. As shown in FIG. 2, the near-infrared pulse light from the infrared light emitting element 21 is formed into a beam to increase the light power density and to limit the detection field of view. Is what you do.

The light receiving section 30 is provided with the light emitting section 20.
A light-receiving element 32 such as a photodiode or a phototransistor that receives the reflected light of the near-infrared pulsed light irradiated from the reflection sheet 12 through the optical system 31 via the optical system 31; A light receiving circuit 33 including a filter for removing a DC voltage due to light; an amplifier circuit 34 for amplifying a weak detection signal from the light receiving circuit 33 and adjusting the gain to a predetermined level by a sensitivity volume 34a; and a pulse from the amplifier circuit 34 A detection circuit 35 for extracting only a signal component from the amplified signal in the shape of a circle, and a smoothing circuit 36 for converting the signal component extracted by the detection circuit 35 into a DC signal.
Is converted into a DC signal and transmitted to the control unit 40.

Here, the optical system 23 is a condensing optical system, and condenses light reflected from the reflection sheet 12 or the surface of the shutter 11 to increase the amount of light received by the light receiving element 32. ing. The light emitting unit 2
0 infrared light emitting element 21, optical system 23 and light receiving section 30
An infrared filter 13 is disposed in front of the optical system 31 and the light receiving element 32. The infrared filter 13 transmits infrared light and cuts visible light, thereby providing visible light as disturbance light. It is configured to eliminate the effects of light.

The control section 40 controls the driving of the light emitting section 20 to light up the infrared light emitting element 21 in pulses, and outputs a detection signal when the detection signal from the light receiving section 30 falls below a predetermined trigger level. It is supposed to. In the case shown in the figure, this detection signal is input to an alarm circuit 41 external to the control unit 40,
1 outputs an alarm signal based on this detection signal.

Here, the control section 40 compares the amount of change in the light receiving level of the detection signal from the light receiving section 30 and the changing time with data set in advance, as shown below. The trigger level is automatically corrected. The automatically corrected trigger level is stored in the EEPROM 42 indicated by a chain line in the drawing. As a result, even when the power supply from the power supply unit 50 is temporarily interrupted due to a power failure or the like, the automatically corrected trigger level is stored, and after the power supply is restarted, the control unit 40
The trigger level of the automatic correction stored in 42 is read out, and the previous state can be restored.

The control unit 40 includes three LEDs 43 for externally displaying sensitivity, an alarm LED 44, and a buzzer 45. The three LEDs 43 for displaying the sensitivity can display the light receiving sensitivity in three stages (for example, low, medium, and high). Also, an alarm LED 44 and a buzzer 4
Reference numeral 5 indicates that when the control unit 40 outputs a detection signal, the control unit 40 is turned on and sounds by the detection signal.

The power supply section 50 rectifies and supplies a constant voltage to a power supply input from the outside, and
Circuits 22, 33, 34, 35, 36 and control unit 40
And the alarm circuit 41 and the EEPROM.

The detecting device 10 according to the embodiment of the present invention is configured as described above. When the detecting device 10 is installed, the light emitting unit 20 emits light to the reflecting sheet 12 of the shutter 11 while emitting light. The optical axes of the detection device 10 and the reflection sheet 12 are adjusted such that the detection fields of the light receiving unit 20 and the light receiving unit 30 are matched and the light receiving level of the light receiving unit 20 becomes maximum. At this time, if the control unit 40 is configured to turn on the three LEDs 43 for sensitivity display at the maximum light receiving level, the optical axis adjustment can be easily performed.

Subsequently, the light receiving level E1 is determined by the amplifier circuit 34.
The sensitivity volume 34a is adjusted so that the saturation voltage becomes, for example, 以上 or more of the saturation voltage. Also in this case, when the light receiving level becomes an appropriate value, the control unit 40 controls the three Ls for sensitivity display.
When the level of the ED 43 is turned on, the light reception level E1 can be easily adjusted. Here, by operating the push switch 46, the light receiving level E1 is stored in the EEPROM 45. After that, the shutter 11 is slightly opened so that the near-infrared pulse light from the light emitting section 20 is irradiated on the surface of the shutter 11 and the reflected light is incident on the light receiving section 30. By operating the push switch 46, the light receiving level E2 at this time is stored in the EEPROM 45. Thus, the control unit 40 calculates the trigger level V1 based on the light receiving levels E1 and E2 as described above, and
5 and make settings. Thus, installation and adjustment of the detection device 10 are completed.

In the detection device 10 installed as described above, the infrared light emitting element 21 of the light emitting section 20 emits a pulse light as shown in FIG. 3A, as shown in FIG. Accordingly, when the shutter 11 is closed, the near-infrared pulsed light from the light emitting unit 20 is reflected by the reflective sheet 12 having a relatively high reflectance of the shutter 11, and the light receiving unit 30
Incident on the light-receiving element 32. Thereby, the light receiving element 32
As shown on the left side of FIG. 3 (B), the detection signal is a light reception level E1 at the time of caution. On the other hand, when the shutter 11 is opened, the near-infrared pulse light from the light emitting unit 20 is reflected on the surface of the shutter 11 having a relatively low reflectance, and the detection signal of the light receiving element 32 is
As shown in the center of (B), the light reception level becomes the light reception level E2 at the time of alarm.

Therefore, the light receiving unit 3 input to the control unit 40
The detection signal from 0 indicates that when the shutter 11 is opened as shown in FIG. 3 (C), the light reception level gradually decreases from E1 at the time of alert to E2 at the time of the alarm, and the light reception level is reduced during that time. When the trigger level V1 becomes lower than the reference trigger level V1, the control section 40 outputs a detection signal as shown in FIG.

Here, the trigger level V1 is determined by the control unit 40 when the detector 10 is installed.
It is set to an appropriate value based on E1 and E2. That is, after the detection device 10 is installed, first, the light reception level E1 at the time of warning and the light reception level E2 at the time of alarm are measured. Then, the control unit 40 determines the light receiving levels E1, E2
The trigger level V1 is obtained from the following equation as an average value of the following: V1 = (E1 + E2) / 2 This is because the most stable detection operation can be obtained when the trigger level V1 is set to an intermediate value between the two light reception levels E1 and E2. The trigger level V1 obtained in this way is E
It is also stored in the EPROM 42.

Next, the surface of the shutter 11 is
When the surfaces of the reflection sheet 12 and the infrared filter 13 serving as a detection window of the detection device 10 become dirty with dust, dust, or the like, FIG.
As shown in the figure, the near-infrared light emission pulse by the infrared light emitting element 21 is the same as that at the time of installation shown in FIG.
As shown in FIG. 4 (B), the light receiving levels at the time of warning and at the time of warning 2 are E3 and E4, respectively. Here, as the light receiving level E3 at the time of warning, the average value of the light receiving level E3 at the time of the last warning can be used.
Cannot be automatically measured, and is calculated by the control unit 40 as an estimated value by the following equation E4 = E2 × E3 / E1, based on the decrease in the light receiving level at the reflection sheet 12, and the trigger level V2 at this time is V2 = (E3 + E4) / 2 = V1 × E3 / E1 Thus, by setting the trigger level V2, the control unit 40 can be set as an intermediate value between the light receiving level E3 at the time of warning and the light receiving level E4 at the time of warning.

Further, when the surface of the shutter 11, the reflection sheet 12, and the surface of the infrared filter 13 which is the detection window of the detection device 10 are further stained by use, the light receiving unit 30
The light receiving level of the detection signal is further reduced, and becomes the light receiving level E5 at the time of warning and the light receiving level E6 at the time of warning. Similarly, the trigger level V3 is obtained by the following equation: V3 = V2 × E5 / E3.

In this way, the control unit 40 samples the light receiving level E3 at the time of alert at a fixed period, finds an average value for a predetermined period, compares it with the light receiving level E1 stored in the EEPROM 45, and finds a difference. In this case, the control unit 40 calculates and sets a new trigger level using the above-described equation of the trigger level V2. As a result, the trigger level is set to an intermediate value between the light receiving level at the time of warning and the light receiving level at the time of alarm, and even if the above-mentioned dirt advances, no malfunction due to dirt occurs and the trigger level is stable for a long period of time. The obtained operation is obtained. Thus, when used as a security shutter sensor, if there is no particular problem, the detection device can be reliably installed without performing maintenance such as checking the function of the sensor and cleaning the reflection sheet for, for example, 10 years or more. Works.

Here, the reflection sheet 1 becomes extremely dirty,
When the difference between the reflectance of the surface of the shutter 2 and the surface of the shutter 11 is almost zero, the light receiving level at the time of warning and the light receiving level at the time of warning become almost the same, so that it is impossible to detect the opening and closing of the shutter 11. . Therefore, preferably, when the difference between the trigger level obtained by calculation and the light receiving level at the time of alert becomes equal to or less than a predetermined value, the control unit 40 outputs an undetectable signal to warn the necessity of maintenance. Has become.

In the above embodiment, the detecting device 10 uses near infrared rays. However, the present invention is not limited to this, and the present invention can be applied to a detecting device using light of another wavelength. it is obvious. Further, in the above embodiment, the trigger level calculated by the control unit 40 and the light reception level E1 at the time of warning are configured to be stored in the EEPROM 45. However, the present invention is not limited to this, and a normal RAM may be used. In this case, a battery for power failure countermeasures may be mounted on the control unit 40, or a capacitor may be used for short-time power failure countermeasures.

Further, when such a memory is used, it is necessary to reset the memory at the time of initial setting. The reset may be performed by using the push switch 46 described above. In this case, since one push switch 46 is operated for resetting data, storing the light receiving level at the time of warning, and storing the light receiving level at the time of alarm, the LED is turned on to identify the operating function. It is also possible to make different sounds with a buzzer.

In the above embodiment, the detection device for detecting the opening / closing of the shutter 11 has been described. However, the present invention is not limited to this, and various devices having an opening / closing member, for example, a door,
It is obvious that the present invention can be applied to a detecting device for detecting opening and closing of a window or the like.

[0036]

As described above, according to the present invention, the reflection member is contaminated by dust, dirt, and the like, and the light is detected from the light receiving unit by the absorption and scattering of the pulse light from the light emitting unit due to the contamination. Even if the signal reception level drops,
The control unit automatically corrects the trigger level based on the light receiving level of the detection signal from the light receiving unit, and the trigger level corresponding to the light receiving level is set. Therefore, even if the light receiving level is reduced due to dirt such as dust and dirt, the trigger level is appropriately adjusted in response to the lowered light receiving level. In addition, malfunctions when the light receiving level fluctuates are reduced. Thus, reliable operation can be performed for a long period of time without cleaning the reflecting member and without manually switching the trigger level. Thus, according to the present invention, with a simple configuration,
There is provided an extremely excellent detection device which performs a stable detection operation without malfunction for a long period of time without malfunction.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a detection device according to the present invention.

FIG. 2 is a schematic perspective view showing an installation state of the detection device of FIG.

FIG. 3 is a time chart showing signals of respective units when the detection device of FIG. 1 is installed.

FIG. 4 is a time chart showing signals of various parts of the detection device of FIG. 1 in a slightly dirty state.

FIG. 5 is a time chart showing signals of various parts of the detection device of FIG. 1 in a further dirty state.

FIG. 6 is a time chart showing a relationship between a light receiving level and a trigger level in a conventional detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Detector 11 Shutter 12 Reflection sheet 13 Infrared filter 20 Light emitting part 21 Infrared light emitting element 22 Light emitting circuit 23 Optical system 30 Light receiving part 31 Optical system 32 Light receiving element 33 Light receiving circuit 34 Amplifier circuit 34a Sensitivity volume 35 Detection circuit 36 Smoothing Circuit 40 Control unit 41 Alarm circuit 42 EEPROM 50 Power supply unit

Claims (5)

[Claims] 1. A reflecting member disposed on a surface of an opening / closing member such as a shutter, a light emitting section for irradiating the reflecting member at a closed position of the opening / closing member with infrared pulse light, and an infrared pulse light. A light receiving unit that receives the reflected light of the following, and a control unit that outputs a detection signal when the trigger level becomes lower than a predetermined trigger level based on the detection signal from the light receiving unit, wherein the control unit is A detection device that compares a light reception level of a detection signal from the light receiving unit with a reference level and sets a trigger level based on a difference between the reference level and the reference level. 2. The detection device according to claim 1, wherein the control unit outputs a signal indicating that detection is not possible when the set trigger level falls below a predetermined value. 3. Based on a detection signal from the control unit,
The detection device according to claim 1, further comprising an alarm unit that outputs an alarm signal to the outside. 4. The detection device according to claim 1, further comprising an amplification unit that amplifies a detection signal from the light receiving unit, performs gain adjustment, and outputs the signal to the control unit. 5. The detection device according to claim 1, further comprising a memory for storing a trigger level set by the control unit.