JP2000018492A - Photodetector for doorway - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photodetector for a doorway, surely capable of detecting an object on the doorway by the presence of the shade of a beam of light to be generated in a space between a light projector and a receiver set up in door ends each. SOLUTION: This doorway photodetector has a light projector 1 generating a beam of light and projecting it, and a light receiver 2 being opposedly set up to the light projector 1 and receiving the light, and the projector 1 and receiver 2 opposedly set up to both side ends of a door or a side end and a fixed part of the door, through which detects an object on the doorway on the basis of light receiving and shading conditions of the light receiver 2. In the case where photoelectric operations are carried out in time of on-off operations of the door, a distance between the projector 1 and receiver 2 is largely varied, but the amplification factor of a factor variable amplifier to amplify a light receiving signal is controlled on the basis of a light receiving quantity of the light receiver by a central processing unit. Therefore, any possible saturation in a light receiving element of the light receiver 2 and in the factor variable amplifier is prevented from occurring, thereby any small object on the doorway at the time of closing the door can surely be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric detecting device for detecting an object on a doorway such as an elevator by detecting the presence or absence of a light beam generated on the doorway.

[0002]

2. Description of the Related Art For example, automatic doors (including a car door and a landing door) at an entrance of an elevator are automatically closed by an operation switch or a timer operation of the elevator, but when an object such as a person is on the doorway. It is desirable to automatically detect the object before the door touches it and stop or open the door.

Therefore, conventionally, both ends of an elevator door (in the case of a one-sided door, the end of the door and a fixed-side receiving portion of the door).
A large number of light-emitting elements and light-receiving elements are arranged at predetermined intervals so as to face each other, and a large number of light beams (light beams) are generated horizontally on the doorway by the light emitted from each light-emitting element, and these light beams are emitted. JP-A-8-208162 discloses a photoelectric detection device that detects an object on a doorway by detecting light-shielded light.
It is proposed in Japanese Patent Publication No.

[0004]

In this type of doorway photoelectric detecting device, a light projecting element and a light receiving element are arranged at the front end (or the door end and a fixed side receiving part) of a door that opens and closes. Therefore, when the door is closed, the distance between the light emitting element and the light receiving element approaches the shortest distance, and when the door is opened, the distance increases to the maximum distance. For this reason, if the light emitting intensity of the light emitting element is set to a sufficient level and the light receiving sensitivity of the light receiving circuit is set to a sufficiently high level so that an object can be detected when the door is fully open, the door closes to near the fully closed position. In the position where the light is received, the light receiving element receives light of high illuminance and is easily saturated. For this reason, when a relatively small object such as a finger or a thin translucent object enters between the doors when the door is closing, the light receiving signal of the light receiving element is very light between the light shielding and the non-light shielding. However, there is a problem that the object is hard to detect and the object is hard to detect.

For this reason, in the above-mentioned conventional photoelectric detecting device,
The average intensity of the light beam generated by the light emitting operation of the light emitting element is calculated according to the opening / closing state of the door, and a value obtained by subtracting a certain coefficient from the average intensity is calculated as a variable threshold every predetermined time, and the threshold is calculated. Although the judgment of the presence or absence of light beam shading, that is, the judgment of object detection, is performed using a light-emitting element and a light-receiving element, when a small object such as a finger enters between doors close to each other that are very close, Similarly to the above, the light receiving element also receives light of high illuminance and saturates, and the amplification operation of the amplifier for amplifying the light receiving signal is saturated, so that there is a problem that a small object is difficult to detect.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and an object on a doorway is controlled by the presence or absence of a light beam generated between a light emitter and a light receiver arranged at an end of a door.
An object of the present invention is to provide a doorway photoelectric detection device that can reliably detect a doorway.

[0007]

In order to achieve the above object, a photoelectric detecting device according to the present invention comprises a light projector for generating and projecting a light beam, and a light receiving device arranged opposite to the light projector for receiving the light beam. A light emitter and a light receiver are installed opposite to both sides of the door or a side end of the door and the fixed portion, and based on a state of light reception and light shielding in the light receiver, a doorway for detecting an object on the doorway. The photoelectric detection device includes: an amplifier for amplifying a light reception signal output from the light receiver; and amplification factor control means for controlling an amplification factor of the amplifier based on an amount of light received by the light receiver. And

[0008]

In the photoelectric detecting device having such a configuration, a light beam is generated on the doorway by the light emitting operation from the light emitting device, and the light receiving device receives the light beam and outputs a light receiving signal.
Whether light reception or light blocking is determined based on the amount of light received from the light receiving signal. In the case of light blocking, an object on the doorway is detected. When the photoelectric detection operation is performed during the opening and closing operation of the door, the distance between the light emitter and the light receiver changes greatly, but the amplification factor of the amplifier for amplifying the light reception signal is based on the amount of light received by the light receiver by the amplification ratio control means. Controlled.

For this reason, when the door is closed, the distance between the light emitter and the light receiver becomes short, and the amount of light received by the light receiver increases, so that the light receiving element and the amplifier for amplifying the signal are saturated,
Although it is difficult to detect a small object, in the present invention, when the amount of light received by the light receiver increases, the gain control means operates to lower the gain of the amplifier, thereby preventing saturation of the light receiving element and saturation of the amplifier. Thus, a small object on the doorway when the door closes can be reliably detected.

Further, if a current control means for controlling the light emission drive current of the light emitter based on the amount of light received by the light receiver is provided, when the door is closed, the distance between the light emitter and the light receiver becomes shorter. When the amount of light received by the light receiver increases, the current control means can control the light emission drive current of the light emitter to decrease. For this reason, the amount of light emitted from the light emitter decreases, and accordingly, the amount of light received by the light receiver decreases, preventing saturation of the light-receiving element and saturation of the amplifier, so that small objects on the doorway when the door closes can be more reliably detected. Can be detected.

Further, when a phototransistor is used as a light receiving element and a light emitting device and a light receiving device are installed in a dark portion, if the light receiving amount of the light receiving device is low, the light receiving limit performance is deteriorated. If a bias light applicator that applies bias light to the light receiving element is disposed in the vicinity, the bias light applicator emits light during the light receiving operation and applies the bias light to each light receiving element, so that the light receiving limit performance can be improved. .

[0012]

Embodiments of the present invention will be described below with reference to the drawings.
It will be described based on. Figure 1 shows an elevator photoelectric detector
FIG. 1 is for many rays at regular intervals
Is a light projector that is generated horizontally by a large number of light emitting elements 1
₁ , 1_Two ~ 1_n Are arranged at regular intervals. 2 is
This is a light receiver that is placed opposite to the light
Optical element 1 ₁ , 1_Two ~ 1_n Multiple receivers
Optical element 2₁ , 2_Two ~ 2_n Consists of

The light transmitter 1 and the light receiver 2 are attached to both ends of a door (a car door or a landing door) of an elevator (in the case of a one-sided door, opposed to a door end and a fixed-side receiving portion of the door). . Light projecting device 1 ₁ of the light projector 1, 1 to ₂ to 1 _n for example, a light-emitting diode is used, the light receiver 2 receiving element 2
For example, a phototransistor is used for ₁ , 2 _{2 to} 2 _n . When a phototransistor is used for the light receiving element,
Although the light receiver 2 can be manufactured at lower cost, the phototransistor has low input sensitivity to weak light due to its characteristics. For this, in the vicinity of the light receiving elements 2 _1, 2 ₂ to 2 _n of the light receiver 2, as a bias light applying device 3, the auxiliary light projecting element 3 _1,
3 ₂ to 3 _n are arranged, and to give to each light receiving element _{2 1,} 2 2 ~2 _n light of the auxiliary light projecting element as a bias light. n indicates the number of light beams generated on the doorway, that is, the number of light projecting elements and light receiving elements.

Reference numeral 4 denotes a light emitting drive circuit, which supplies a current to each light emitting element of the light emitting device 1 to emit light. The output current of the light emitting drive circuit 4 is controlled by a current control circuit 9, which controls the amount of light emitted from the light projector 1 (the amount of light emitted from the light emitting element). The current control circuit 9 controls an output current value of the light emitting drive circuit 4 according to a control signal CTL from a controller 20 described later. The control signal CTL is of two types, for example, a large current and a small current.

Reference numeral 6 denotes a time-division circuit on the light emitting side, which comprises a counter having an output terminal corresponding to each light emitting element.
A clock signal CLK from a controller 20 described later is input, and a light emitting timing signal for each light emitting element is sequentially output to the gate circuit 5 for each light emitting cycle. The gate circuit 5 has an output circuit corresponding to each light emitting element, and superimposes the carrier wave sent from the carrier wave generating oscillation circuit 7 on the light emitting timing signal for light emission output from the time division circuit 6. Let it.

Reference numeral 8 denotes a carrier output control circuit connected to the output side of the oscillation circuit 7, and a time division circuit for dividing the carrier pulse signal sent from the oscillation circuit 7 into each light emitting cycle. The (n + 1) th signal from 6 is input, and the carrier is divided for each light emitting cycle.

Reference numeral 10 denotes an analog switch constituted by a multiplexer or the like, which is provided on the output side of the light receiver 2.
Each light-receiving element 2 ₁ , 2 _{2 of the} light-receiving device 2 according to a light-receiving timing signal output from a later-described light-receiving side time-division circuit 11.
~ 2 _n output circuits are switched in sequence, and
4 input side. The time-division circuit 11 receives the clock signal CLK and the synchronization signal SYNC from the controller 20, and sets the time according to the clock signal CLK so as to generate n light reception timings for each light reception cycle specified by the synchronization signal SYNC. The divided light receiving timing signals are sequentially output to the analog switch 10.

Reference numeral 12 denotes a drive circuit for sequentially driving the auxiliary light projecting elements 3 ₁ , 3 _{2 to} 3 _n of the bias light applicator 3 in accordance with a predetermined light receiving timing. It is connected via a gate circuit 13 composed of a circuit or the like.

FIG. 2 shows a block diagram of the controller 20. The controller 20 is mainly configured by a CPU 21. The CPU 21 determines whether light reception or light blocking is performed based on an output signal V6 from the comparison circuit 26 based on a program stored in advance. Further, the CPU 21 receives the carrier wave CAR from the light emitting circuit side, and generates a synchronization signal SYNC for making a cut at the beginning and end of each light emitting cycle.
And outputs the light reception signal D according to the amount of light received by the light receiver 2.
The amplification factor of the variable gain amplifier 22 for amplifying P is increased or decreased by the amplification factor adjustment signal, and the output current of the light projection drive circuit 4 for driving the light projector 1 is controlled by the control signal CT.
It operates so as to control the projected light amount (light emission amount of the light emitting element) by increasing or decreasing by L.

The variable gain amplifier 22 receives the light receiving signal DP from the light receiving side through the preamplifier 14, amplifies the light receiving signal at the gain specified by the CPU 21, and outputs it to the synchronous detection circuit 23. The amplification factor is, for example, CP
It is set by U21. The synchronous detection circuit 23 receives the received light signal V2 amplified by the variable amplification factor amplifier 22, inputs the carrier wave CAR from the output control circuit 8 on the light projecting side through the delay circuit 25, and synchronizes the received light signal with the carrier wave. Is detected and output. In the delay circuit 25, a time period from the time when the light projector 1 emits light to the time when the light receiving signal is output from the light receiver 2 is set, for example, about several μsec to 10 μsec.

Reference numeral 24 denotes a voltage storage circuit connected to the output side of the synchronous detection circuit 23, which is a voltage V3 of the detected light reception signal.
Is accumulated within a preset accumulation time t3, thereby converting the accumulated amount of the received light signal into a voltage, and outputting it as a voltage signal V4 to the comparison circuit 26. Time t3 is 1
This is a schematic light receiving time of the optical axis. The comparing circuit 26 compares a preset set value V5 with the voltage value V4 of the light receiving signal from the voltage storage circuit 4, and sends to the CPU 21 a light receiving detection signal V6 having a pulse width equal to or larger than the set value as a pulse width. Output.

The CPU 21 calculates a time t5 from the rise of the accumulation time t3 to the rise of the light reception detection signal V6, stores this time t5 as light reception data, and when the light reception data t5 is shorter than a preset value, It is determined that light is received. Also, CP
U21 outputs an object detection signal if it is determined that even one light beam is blocked during the light projection / light reception scanning. Reference numeral 27 denotes an output circuit of the CPU 21 comprising a relay circuit or the like, which operates the relay circuit or the like to input the object detection signal output from the CPU 21 and drive the door control circuit.

Next, the operation of the photoelectric detection device will be described with reference to FIG.
This will be described with reference to the flowchart of FIG. 4 and the timing chart of FIG.

The door of the elevator moves from the opening operation to the closing operation,
When the operation of the photoelectric detection device starts, the controller 20
First, the CPU 21 sets the gain of the variable gain amplifier 22 in step 100. The amplification rate is, for example, 0 to 31.
Is prepared, and an intermediate value, for example, 18 is set at the start of operation.

The time-division circuit 6 on the light emitting side includes a controller 2
0 to the same gate circuit 5
A pulse signal is output in order, and the gate circuit 5
Are transmitted to the light emitting drive circuit 4.
Can be The light emitting drive circuit 4 is provided for each light emitting element 1 of the light emitting device 1.₁ ,
1_Two ~ 1_n Are sequentially operated to emit light, and each light emitting element 1₁ , 1 _Two 
~ 1_n Light rays are generated in order from
Let me do it.

Each light beam is applied to each light receiving element 2 ₁ , 2 _{2 of the} light receiver _2.
2n , the time-division circuit 11 on the light-receiving side sequentially switches the analog switches 10 based on the same clock signal CLK and synchronization signal SYNC used during light emission, and 2 ₁ , 2 ₂ to 2 _n
Are sequentially connected to the preamplifier 14 so that each light receiving signal D
P is transmitted to the controller 20 through the preamplifier 14.

Each light receiving signal DP is input to the variable gain amplifier 22 and amplified at the gain set by the CPU 21. After being amplified, each received light signal DP is sent to the synchronous detection circuit 23, which inputs the carrier wave CAR from the light output side output control circuit 8 through the delay circuit 25 and synchronizes with the carrier wave CAR. To detect the received light signal,
The detected signal V3 is output to the voltage storage circuit 24. At this time, the voltage accumulation circuit 24 accumulates the voltage of the signal V3 within the accumulation time t3 given by the CPU 21, thereby converting the accumulation amount of the received light signal into a voltage, and converting it into a voltage signal V4 as a voltage signal V4. Output to

The comparison circuit 26 has a predetermined set value V
5 is compared with this voltage signal V4, and a light reception detection signal V6 having a pulse width equal to or greater than the set value as the pulse width of the voltage signal V4.
Is output to the CPU 21 (step 110). CPU2
1 is the light reception detection signal V6 from the rise of the accumulation time t3.
Is calculated as time t5, and this time t5 is stored as received light data. If the received light data t5 is shorter than a preset set value, it is determined that light is received. Step 120). In the case of light reception, the process proceeds to step 130, where a light reception flag is set. In the case of light reception, the process proceeds to step 150, in which a light shielding flag is set.

In the case of shading, even if shading is performed on one optical axis, the process proceeds to step 160, where an object detection signal is output to the output circuit 27 as shading processing, and stop and open control of the door is performed. On the other hand, in the case of light reception, the next step 14 is
The process proceeds to 0, and it is determined whether or not all the optical axes have been determined. If all the optical axes have not been determined, the process proceeds to step 170, and the above steps 100 to 170 are repeated.

If the determination has been made for all the optical axes, the process proceeds to step 180, where it is determined whether or not the light-shielding flag has been set. It is determined whether or not the control value of the light emission current output to the current control circuit 9 on the side is “small”. If the control value of the light emission current is “small”, the process proceeds to step 200, and It is determined whether or not the amplification factor to be applied is equal to or greater than “29”. If the amplification factor is equal to or greater than “29”, the process proceeds to step 230, and the photoelectric detection distance is set to “long distance”.

On the other hand, when it is determined in step 190 that the control value of the projection current is not "small", the process proceeds to step 210, and it is determined whether or not the amplification factor given to the amplification factor variable amplifier 22 is "9" or more. If the amplification factor is “9” or more, the process proceeds to step 220, and the photoelectric detection distance is set to “far distance”. On the other hand, if the amplification factor is not “9” or more in step 210, or if the amplification factor is not “29” or more in step 200, the process proceeds to step 240.

In step 240, it is determined whether or not the amount of received light is equal to or less than a specified value based on whether or not the received light data t5 captured by the CPU 21 is longer than a preset set value. If it is longer, it is determined that the amount of received light is equal to or less than the specified value, and the process proceeds to step 250, where the amplification factor is increased by, for example, one. If the received light data t5 is shorter than the preset value, it is determined that the received light amount is not less than the specified value, and then the process proceeds to step 260, where it is determined whether the received light amount is not less than the specified value.

If the received light data t5 is shorter than a preset value, it is determined that the amount of received light is equal to or greater than a specified value.
It is determined whether the amplification factor is minimum. If the amplification factor is minimum, the process proceeds to step 280 to set the photoelectric detection distance to “short distance”. On the other hand, if it is determined in step 270 that the amplification factor is not the minimum, then in step 290
To reduce the amplification factor by, for example, one. Step 2
If it is determined at 60 that the received light data t5 is not shorter than the preset value and the amount of received light is not more than the specified value, the process proceeds to step 300. Thus, the received light data t
When 5 is shorter than a preset value and the amount of received light is larger than a specified value, the gain of the variable gain amplifier 22 is controlled to be reduced.

In step 300, it is determined whether or not all the optical axes have been determined. If all of the optical axes have not been determined, in step 310, after receiving the light receiving signal of the next optical axis, Returning to step 180, steps 180-30
The process up to 0 is repeated.

If all the optical axes have been determined, the process proceeds to step 320, where it is determined whether or not the control value of the projection current output to the current control circuit 9 on the projection side is "small". When the control value of the current is “small”, the process proceeds to step 360. Here, it is determined whether the setting of the photoelectric detection distance is “far distance”,
If “far distance” is set, in step 370,
The control value of the light emission current is set to “large”, and this processing ends. If it is determined in step 360 that "far distance" has not been set, the process is terminated as it is, and the above steps 100 and thereafter are repeated again.

On the other hand, when it is determined in step 320 that the control value of the light emission current output to the current control circuit 9 on the light emission side is not "small", the flow advances to step 330 to set the photoelectric detection distance. Is determined to be "far distance", and if it is set to "far distance", this processing is finished as it is, and the above-mentioned step 100 and subsequent steps are repeated again. On the other hand, "far distance"
If it is determined that is not set to
The process proceeds to 0, and it is determined whether or not the setting of the photoelectric detection distance is “short distance”. If it is set to “short distance”, the process proceeds to step 350, and the control value of the light emission current is set to “small”. After setting, this processing is completed, and the above-mentioned step 100 and subsequent steps are repeated again.

Therefore, when the amplification factor of the variable amplification factor amplifier 22 is minimum and the photoelectric detection distance is set to “short distance”,
The control value of the emission current is set to "small",
Control is performed so as to reduce the amount of projected light. Step 34
If it is determined at 0 that the distance is not set to "short distance", this processing is terminated as it is, and the above-mentioned steps 100 and thereafter are repeated again.

[0038] Thus, the light projecting element 1 ₁ of the projector 1 of the photoelectric detection device, 1 ₂ to 1 _n is sequentially operating light projecting and receiving unit 2
Are projected toward the respective light receiving elements 2 ₁ , 2 ₂ to 2 _n
Sequentially receive the light, that is, each light axis, and the amount of received light, that is, the received light data, is taken into the CPU 21, and the CPU 21 determines whether the light is received or blocked, and during this time, the door of the elevator gradually closes. In this case, the distance between the light projector 1 and the light receiver 2 gradually decreases, and the amount of light received by the light receiving element increases.

However, when the amount of received light increases by performing the above processing, the control value of the light emission current output to the current control circuit 9 is set to "small" to control the light emission current to decrease. In addition, since the control is performed so that the command value of the amplification factor given to the amplification factor variable amplifier 22 is gradually reduced, the projection light amount of the projector 1 becomes smaller as the distance between the doors, that is, the distance between the projector 1 and the light receiver 2 becomes shorter. And the amount of received light also decreases. For this reason, it is possible to prevent the light receiving element of the light receiver 2 from being saturated and prevent the amplification operation of the amplifier 22 from being saturated, and to reliably detect the object on the doorway.

Further, photoelectric detection of an elevator doorway.
In the case of the device, the light emitter 1 or the light receiver 2 is dark inside the door.
It is often installed in a part,
If you use a transistor and place it in such a dark area,
In this case, if the light receiving amount of the light receiver 2 is low, the light receiving limit performance is reduced.
You. However, as described above, each light receiving element 2 of the light receiver 2
₁ , 2_Two ~ 2_n Is provided as a bias light applicator 3 in the vicinity of
Auxiliary light emitting element 3₁ , 3_Two ~ 3_n Are arranged, and during light receiving operation
Each auxiliary light emitting element emits light, and bias light is emitted from each light receiving element 2.
₁ , 2_Two ~ 2_n To improve the light receiving limit performance
Can be

In the above embodiment, an example in which the present invention is applied to an elevator door has been described. However, the present invention can also be applied to an apparatus for detecting an object on a doorway of another openable and closable door.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a controller 20 of the apparatus.

FIG. 3 is a flowchart for explaining the operation of the apparatus.

FIG. 4 is a flowchart for explaining the operation of the apparatus.

FIG. 5 is a timing chart showing signal waveforms of various parts of the circuit of the device.

[Explanation of symbols]

 Reference Signs List 1-light emitter 2-light receiver 3-bias light applicator 4-light emission drive circuit 9-current control circuit 20-controller 21-CPU 22-variable gain amplifier 23-synchronous detection circuit 24-voltage storage circuit 26-comparison circuit

Claims (3)

[Claims] 1. A light source for generating and projecting a light beam, and a light receiving device arranged opposite to the light emitting device and receiving the light beam, wherein the light emitting device and the light receiving device are on both side ends of the door or on the side of the door. A doorway photoelectric detection device that is installed to face the end and the fixed portion and detects an object on the doorway based on a state of light reception and light blocking in the light receiver, wherein a light reception signal output from the light receiver is A doorway photoelectric detection device, comprising: an amplifier for amplifying; and amplification factor control means for controlling an amplification factor of the amplifier based on an amount of light received by the light receiver. 2. The doorway photoelectric detecting device according to claim 1, further comprising current control means for controlling a light emitting drive current of the light emitting device based on an amount of light received by the light receiving device. 3. The doorway photoelectric detection device according to claim 1, wherein a bias light applicator for applying a bias light to the light receiving element is arranged near each light receiving element of the light receiving element.