JP3787712B2 - Detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a detection device for detecting, for example, a change in incident light on a light receiving element and detecting the presence of an intruder or the like in a predetermined detection area.
[0002]
[Prior art]
Conventionally, such a detection device for crime prevention is configured, for example, as shown in FIG. That is, in FIG. 10, the detection device 1 includes a base 2 attached to, for example, a ceiling or a wall, a sensor unit 3 attached to the surface (ie, the lower surface) of the base 2, and a base so as to surround the sensor unit 3. 2 and a cover 4 attached to 2.
[0003]
The sensor unit 3 includes, for example, a pyroelectric element 3c that detects a far-infrared energy amount emitted from an object as a passive sensor, and a far-infrared energy amount generated by the movement of a person who has entered the detection visual field 5. A change is detected, and an intruder or the like can be detected based on the change.
[0004]
[Problems to be solved by the invention]
By the way, in the detection apparatus 1 having such a configuration, an obstacle that intentionally invalidates the detection visual field 5, for example, an obstruction cover that completely covers the cover 4, is placed on the outer surface of the cover 4. When the tape is attached or the paint is applied, the detection visual field 5 is blocked, and the detection device 1 cannot detect an intruder or the like. For this reason, conventionally, as shown in FIG. 10, by providing an obstacle detection unit 6 in the vicinity of the detection visual field 5 (or in the detection device 1) and causing the infrared light emitting element 3a to emit light at predetermined time intervals, The detection signal from the infrared light receiving element 3b at that time is monitored.
[0005]
Thus, for example, when the cover 4 is covered in the detection visual field 5, a tape is attached to the outer surface of the cover 4, or a paint is applied, the detection signal from the infrared light receiving element 3b changes. To do. Thus, the obstacle detection unit 6 detects the obstacle described above based on the change in the amount of reflected infrared light from the infrared light emitting element 3a.
[0006]
However, such an obstacle detection method by the obstacle detection unit 6 detects an obstacle located outside the cover 4 from the inside of the cover 4. Therefore, since the change in the amount of reflected infrared light due to the obstacle is small, the obstacle detector 6 for detecting the change in the amount of reflected light has a problem in that its circuit configuration is complicated and the cost is increased. .
[0007]
On the other hand, the light receiving element is disposed inside the cover, and the light emitting element is disposed outside the cover in the vicinity of the main body of the detection device, so that an obstacle is directly connected from the light emitting element to the light receiving element. Although some detection devices are designed to detect obstacles when the optical path is interrupted, it is necessary to modify the detection device itself. There is a problem that it is necessary to readjust the detection area of the detection device installed in the system.
[0008]
In view of the above, the present invention has an object to provide a detection device that can detect an obstacle in a detection visual field with a simple configuration at low cost.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a base attached to a ceiling, a wall surface, etc., a sensor part attached to the surface of the base, and a cover attached to the base so as to surround the sensor part. In the detection device, an obstacle detection sensor is provided outside the cover, and the obstacle detection sensor complements the detection area of the sensor unit with a light emitting / receiving unit for detecting a change in reflectance near the cover surface. A light receiving / emitting unit for detecting a change in reflectance in the region, each light receiving / emitting unit including two light emitting elements and one light receiving element, the first light emitting element, the light receiving element, and the second The light emitting elements are arranged in order .
[0013]
According to the above configuration, since the obstacle detection sensor for detecting the change in reflectance near the cover surface is provided outside the cover, in order to intentionally invalidate the detection visual field of the detection device. If you install an obstruction cover that covers the cover, sticks tape to the outer surface of the cover, or applies paint or sprays it, the obstacle detection sensor will detect the obstruction cover, tape, or paint. An obstacle is detected by detecting a change in reflectance or a change in reflectance caused by the hand of a person who handles these obstructing covers, tapes or paints.
Therefore, the detection device can always reliably detect an intruder or the like without being obstructed by the obstruction cover.
[0014]
When the obstacle detection sensor includes a light emitting element that irradiates light near the surface of the cover and a light receiving element that receives reflected light from these positions, the light emitted from the light emitting element is While irradiating the vicinity of the surface of the cover, the light receiving element receives light reflected by the obstacle in these regions.
[0015]
When the obstacle detection sensor includes two light emitting elements and one light receiving element, and the light emitting elements on both sides are arranged in the order of the first light emitting element, the light receiving element, and the second light emitting element, Since light is irradiated in different directions and the reflected light of these lights is received by the central light receiving element, a wide detection area for an obstacle can be obtained.
[0016]
Further, when the obstacle detection sensor further includes a unique detection area that complements the detection area of the sensor unit, the detection area of the detection device itself is supplemented by the unique detection area of the obstacle detection sensor. Therefore, an obstacle near the detection device can be detected, and detection accuracy is improved.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on the embodiments shown in the drawings.
FIG. 1 shows an embodiment of a detection device according to the present invention. The detection device 10 includes a base 11 attached to, for example, a ceiling and a wall surface, and a sensor unit 12 attached to the surface (ie, the lower surface) of the base 11. And a cover 13 attached to the base 11 so as to surround the sensor unit 12.
[0019]
The sensor unit 12 is composed of a pyroelectric element that detects the amount of far-infrared energy emitted from an object, for example, as a passive sensor, and changes in the amount of far-infrared energy generated by the movement of a person who has entered the detection visual field 14. And intruders can be detected based on the change.
[0020]
The cover 13 is formed in a hemispherical shape in the illustrated case, is made of a material that can transmit infrared rays, and is fixed to the base 11 by fixing means (not shown).
[0021]
The above configuration is substantially the same configuration as the conventional detection device 1, but in the detection device 10 according to the embodiment of the present invention, an obstacle detection sensor 20 is further provided outside the cover 13.
The obstacle detection sensor 20 has a first detection region A for detecting the reflectance near the surface of the cover 13 of the detection device 10 and a second detection region B for complementing the detection visual field 14 of the detection device 10. ing.
[0022]
The obstacle detection sensor 20 is configured as shown in FIGS.
3 to 5, the obstacle detection sensor 20 surrounds the base 21, for example, a base 21 attached to a ceiling, a wall surface, etc., a substrate 22 attached to the surface (ie, the lower surface) of the base 21, and the substrate 22. And a cover 23 attached to the base 21.
[0023]
On the substrate 22, a light receiving element 24 is arranged in the center along the upper edge and the lower edge in FIG. 3, and light emitting elements 25 and 26 are arranged on both sides, respectively. A light shielding plate 27 is provided between the light receiving elements 24 and the light emitting elements 25 and 26 in order to prevent light from wrapping around. The light receiving element 24 and the light emitting elements 25 and 26 are entirely covered with a substrate case 28 made of, for example, a visible light cut filter in order to block disturbance light.
[0024]
Furthermore, terminal blocks 29 for supplying power to the obstacle detection sensor 20 and for outputting a detection signal from a detection circuit described later are provided at both ends of the substrate 22.
The light receiving element 24 and the light emitting elements 25 and 26 do not include an optical system such as a lens. However, it is sufficient if the distance between the detection areas A and B is about 50 cm. This can be realized by using the light receiving element and the light emitting element.
[0025]
Further, a detection circuit 30 as shown in FIG.
In FIG. 6, the detection circuit 30 uses, for example, a photodiode, a phototransistor, or the like as the light receiving element 24 for the two detection areas A and B described above, and uses an infrared LED as the light emitting elements 25 and 26. In addition, light projecting circuits 31a and 31b for driving these light emitting elements 25 and 26 to emit light, and an oscillation circuit 32 for controlling and generating drive pulses of a predetermined time and frequency for the light projecting circuits 31a and 31b, and The external light compensation circuits 33a and 33b, which eliminate the influence of DC light from sunlight, illumination lamps, etc., or disturbance light flickering at a commercial power supply frequency when a signal from the light receiving element 24 is input, and each external light compensation circuit 33a , 33b, a log amplifier circuit 34 that prevents the output signal from being saturated even when the signal is large, and a detector circuit 3 that rectifies the signal from the log amplifier circuit 34 And a smoothing circuit 36 that smoothes the signal from the detection circuit 35, and the signal from the smoothing circuit 36 is compared with the trigger levels set by the H trigger level setting circuit 37 and the L trigger level setting circuit 38. A window comparator circuit 39 that outputs a signal when the trigger level deviates between two trigger levels, an alarm circuit 40 that issues an alarm when a signal is output from the window comparator circuit 39, and a signal from the alarm circuit 40 to the outside And a relay circuit 41 for notification.
[0026]
Each circuit described above is driven by a power supply circuit 42 to which power is supplied from the power input terminal 29b of the terminal block 29.
[0027]
The log amplifier circuit 34 increases the dynamic range of the input signal, and even when the amount of reflected light in the detection area A and the detection area B is large, the output of the amplifier does not saturate, and the change in the amount of reflected light due to an obstacle. Is surely detected.
[0028]
The H trigger level setting circuit 37 and the L trigger level setting circuit 38 automatically set the trigger level of the window comparator circuit 39 based on the magnitude of the output signal V _I of the smoothing circuit 36, and the log amplifier circuit. The obstacle detection sensitivity by 34 is also corrected.
The trigger level setting by these circuits does not respond to a sudden change in the input signal, and has a delay time of, for example, several seconds or more.
[0029]
FIG. 8 shows a specific configuration example of the H trigger level setting circuit 37 (FIG. 8A) and the L trigger level setting circuit 38 (FIG. 8B).
In FIG. 8, the trigger level setting circuit 50 includes an operational amplifier 51, a capacitor C connected between the non-inverting input terminal of the operational amplifier 51 and the ground, a diode D connected to the non-inverting input terminal and a constant voltage power source, The smoothing circuit 36 includes a resistor R ₁ connected between the input terminal and the ground, and an FET connected between the inverting input terminal and the output terminal via the resistor R ₂ and having a gate connected to the non-inverting input terminal. signal V _I of are input to the non-inverting input terminal via the resistor R ₃ from.
The output signal V _H responds with a delay of several seconds or more with respect to the input signal V _I due to the time constant of R ₃ × C. Further, even if the amount of light received by this apparatus changes due to changes over time, it is possible to maintain stable sensitivity at all times.
[0030]
Here, the trigger level V _H of the H trigger level setting circuit 37 is determined by the circuit of FIG.
V _H = {(R ₁ + R ₂ + R _F ) / R ₁ } × V _I
Setting is performed by the following formula.
On the other hand, when the trigger level V _L of the L trigger level setting circuit 38 is R ₄ = R ₅ in the circuit of FIG. 8B, the L trigger level V _L is
V _L = 2V _I −V _H
Setting is performed by the following formula.
[0031]
With such a configuration, the window comparator circuit 39 operates as shown in the operation waveforms of FIG. That is, when the reflected light is small, as shown in FIG. 9A, the input signal V _I is small and the trigger level is set wide by the two trigger level setting circuits 37 and 38. On the other hand, when there is a lot of reflected light, as shown in FIG. 9B, the input signal V _I increases and the trigger level is set narrow by the two trigger level setting circuits 37 and 38. In this way, a constant obstacle detection sensitivity can be obtained at all times.
[0032]
The alarm circuit 40 outputs an obstacle detection signal, that is, an alarm signal to the outside, does not output an alarm for a predetermined time from when the power is turned on, and further outputs an alarm signal only once or continuously. It is configured to switch whether to output automatically, or to provide an alarm reset switch and an alarm indicator as necessary.
[0033]
The detection apparatus 10 according to the present embodiment is configured as described above, and when there is no intruder or the like in the detection visual field 14, there is no change in the amount of far-infrared energy from the detection visual field 14. No signal is output from the pyroelectric element of the unit 12.
[0034]
When an intruder or the like enters the detection visual field 14 from this state, the amount of far infrared energy received by the pyroelectric element of the sensor unit 12 by the intruder or the like changes. The change in the far-infrared energy amount is appropriately processed by a processing circuit (not shown) provided in the sensor unit 12 so that the presence of an intruder or the like is detected.
[0035]
On the other hand, the obstacle detection sensor 20 operates as follows.
That is, the light emitting elements 25 and 26 are pulse-driven by the oscillation circuit 32 as shown in FIG. The light emitted from the light emitting elements 25 and 26 is applied to the obstacle detection area A near the surface of the cover 13 of the detection apparatus 10, and the reflected light in this area enters the light receiving element 24 and is detected. The
For example, when trying to invalidate the detection function of the detection device 10, there are obstacles such as the cover 13 being covered, tape being stuck to the surface of the cover 13, or paint being applied or sprayed to the surface of the cover 13. In some cases, the amount of received light may be reduced or increased.
Here, when there is an obstacle, as shown in FIG. 7B, the amount of light received by the light receiving element 24 is relatively large when there is no obstacle, and decreases when there is an obstacle.
[0036]
The detection signal of the light receiving element 24 is input to the log amplifier circuit 34 via the external light compensation circuits 33a and 33b. Here, the log amplifier circuit 34 increases the dynamic range of the input signal so that the output signal is not saturated.
Accordingly, as shown in FIG. 7C, the output signal of the log amplifier circuit 34 is relatively large when there is no obstacle, and is small when there is an obstacle.
[0037]
Subsequently, the output signal from the log amplifier circuit 34 is rectified by the detection circuit 35, becomes as shown in FIG. 7D, is further smoothed by the smoothing circuit 36, and becomes a DC output signal V _I.
In this case, the output signal V _I is relatively large when there is no obstacle, and is small when there is an obstacle.
[0038]
Next, the output signal V _I is compared with the trigger levels V _H and V _L set by the H trigger level setting circuit 37 and the L trigger level setting circuit 38 in the window comparator circuit 39, and from between these two trigger levels. In the case of disconnection, a detection signal is output from the window comparator circuit 39.
In this case, if there is an obstacle, the output signal V _I becomes small as shown in FIG. _7E , but the trigger level V _H , set by the H trigger level setting circuit 37 and the L trigger level setting circuit 38, As described above, V _L responds with a delay of several seconds due to the time constant due to the resistors R ₃ and C, so that the output signal V _I temporarily deviates from the trigger level.
As a result, an obstacle is detected, and the window comparator circuit 39 outputs a detection signal as shown in FIG.
[0039]
Thus, the alarm circuit 40 outputs an alarm signal based on the detection signal from the window comparator circuit 39, and outputs an alarm signal to the outside from the alarm output terminal 29a of the terminal block 29 via the relay circuit 41. .
[0040]
Here, the above description has been given of the case where the amount of incident light on the light receiving element 24 of the obstacle detection sensor 20 decreases due to the presence of an obstacle, but in the case where the amount of incident light on the light receiving element 24 increases due to the presence of an obstacle. In response to the amount of light incident on the light receiving element 24, the detection signal is output from the light receiving element 24, whereby the level of the output signal V _I from the smoothing circuit 36 is increased, and the window comparator circuit 39 causes the H trigger. The level V _H will be exceeded, and similarly, an alarm signal is output, so that an obstacle can be detected.
[0041]
Further , regarding the detection area B, if there are obstacles such as banners or posters in the detection area B that obstruct the detection visual field 14 of the detection device 10, these obstacles can be detected in the same manner. Become.
[0042]
Here, since the obstacle detection sensor 20 is configured to be disposed in the vicinity of the outside of the cover 13 with respect to the conventional detection device 10, the existing detection device 10 is in use. This detection device can be easily configured by adding an obstacle detection sensor 20 in the vicinity thereof without having to modify or readjust the detection device.
[0043]
In the above embodiment, the obstacle detection sensor 20 uses an infrared reflection sensor, but is not limited to this, and other detection sensors such as a position detection element (PSD) and an ultrasonic sensor are also used. Obviously it can.
In the above embodiment, the substrate case 18 is configured as a visible light cut filter. However, the present invention is not limited to this, and the substrate case 18 may be omitted and the cover 23 may be configured as a visible light cut filter. Good.
Furthermore, in the said embodiment, although the sensor part 12 is comprised as what is called an infrared passive sensor which receives the infrared rays from the outside, it is not restricted to this but what is called a reflection type provided with the infrared light emitting element and the infrared light receiving element. Obviously, it may be an infrared active sensor or an ultrasonic or microwave Doppler detection type sensor.
Moreover, in the said embodiment, although the bases 11 and 21 were demonstrated so that it might be attached to a ceiling etc., for example, it is clear that it may be attached not only to this but to a perpendicular | vertical or diagonal wall surface.
[0044]
【The invention's effect】
As described above, according to the present invention, the obstacle detection sensor for detecting the change in reflectance near the cover surface is provided outside the cover. If you try to install an obstruction cover that covers the cover, apply tape to the outer surface of the cover, or apply paint or spray it, the obstruction detection sensor will detect these obstructions. Obstacles are detected by detecting a change in reflectance due to a cover, tape, or paint, or a change in reflectance caused by a person handling the cover, tape, or paint.
Therefore, the detection device can always detect an intruder or the like without being obstructed by the obstruction cover.
Thus, according to the present invention, it is possible to provide an extremely excellent detection device that can detect an obstacle in the detection visual field with a simple configuration at low cost.
[Brief description of the drawings]
FIG. 1 is a schematic side view showing an embodiment of a detection device according to the present invention.
FIG. 2 is a schematic plan view showing the detection device of FIG. 1;
3 is a plan view of an obstacle detection sensor in the detection apparatus of FIG. 1 with a cover removed. FIG.
4 is a side view of the obstacle detection sensor of FIG. 3;
5 is a cross-sectional view of the obstacle detection sensor of FIG.
6 is a block diagram illustrating a circuit configuration example of the obstacle detection sensor of FIG. 3;
7 is a time chart showing signals at various parts in the circuit of FIG. 6. FIG.
8 is a circuit diagram showing a specific example of a level setting circuit in the circuit of FIG. 6. FIG.
9 shows operation waveforms in the case of the window comparator circuit in the circuit of FIG. 6 when (a) there is little reflected light and (b) there is much reflected light.
FIG. 10 is a schematic sectional view showing an example of a conventional detection device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Detection apparatus 11 Base 12 Sensor part 13 Cover 14 Detection visual field 20 Obstacle detection sensor 21 Base 22 Substrate 23 Cover 24 Light receiving element 25, 26 Light emitting element 27 Light shielding plate 28 Board case 29 Terminal block 30 Detection circuit 31a, 31b Light projection circuit 32 Oscillation circuits 33a and 33b External light compensation circuit 34 Log amplifier circuit 35 Detection circuit 36 Smoothing circuit 37 and 38 Trigger level setting circuit 39 Window comparator circuit 40 Alarm circuit 41 Relay circuit 42 Power supply circuit

Claims (1)

In a detection device including a base attached to a ceiling, a wall surface, etc., a sensor part attached to the surface of the base, and a cover attached to the base so as to surround the sensor part,
An obstacle detection sensor is provided outside the cover ,
The obstacle detection sensor detects the reflectance change in the vicinity of the cover surface, and the light reception / emission for detecting the reflectance change in a unique region that complements the detection region of the sensor unit. And comprising
Each of the light receiving and emitting units includes two light emitting elements and one light receiving element, and is configured by arranging in order of a first light emitting element, a light receiving element, and a second light emitting element . Detection device.

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