JP2001050710A - Method of adjusting light reflection sensor in device for detecting passage of object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for detecting the passage of an object, capable of inexpensively realizing the detection of the passage of the object with high reliability. SOLUTION: In an adjustment method of a light reflection sensor in a device for detecting the passage of an object to be detected such as coin by using the light reflection sensor, a first detection output level V1 of a light receiving amount by a light receiving element in a state that the object to be detected is detected, and a second detection output level V2 of a light receiving amount by the light receiving element in a state that the object to be detected is not detected, are measured while varying a light emitting amount from a light emitting element of the optical sensor, to determine the difference V1-V2 between the first detection output level and the second detection output level, and the light emitting amount of the maximum difference V1-V2 is used as an adjustment value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object passage detecting device for detecting the passage of a detected object such as a coin by using a light reflection sensor, and more particularly to realizing highly reliable object passage detection without increasing the cost. The present invention relates to a method of adjusting a light reflection sensor in an object passage detection device that can perform the operation.

[0002]

2. Description of the Related Art In general, there is known an object passage detecting device which detects the passage of a detected object such as a coin by using a light reflection sensor. In this case, a light-emitting element and a light-receiving element are mounted on the same package. Light reflection sensors with short distances are often used. As shown in FIG. 6, an object passage detection device using this light reflection sensor has a gap 1 at a predetermined interval.
A light reflection sensor 7 having a light emitting element 7a and a light receiving element 7b is disposed above the gap 1 on the transport path 5 of the detected object 3 such as a coin having And a voltage detector 11 for detecting the output level of the amount of received light is provided on the light receiving element 7b side. The operation of the object passage detection device is as follows. When the detected object 3 passes through the gap 1 on the transport path 5 in a state where a predetermined amount of light is emitted from the light emitting element 7a of the light reflection sensor 7, the light receiving element The amount of light received by 7b changes. That is, when the detected object 3 is not present in the gap 1, the amount of received light is small, and the output level is also small. Conversely, when the detected object 3 is in the gap 1, the amount of received light increases, and the output level also increases. Therefore, if the increased output level is detected by the voltage detector 11 of the light receiving element 7b, the passage of the detected object 3 can be detected. The light reflection sensor 7 is particularly advantageous for a small-sized device because it has better space efficiency than a transmission-type light sensor. However, the light reflection sensor has a very large variation in the light conversion efficiency in manufacturing, and the output voltage greatly changes due to the variation in the reflectance of the surface of the detected object because it is a reflection sensor. Therefore, adjustment in consideration of these is indispensable. Conventionally, there have been the following two adjustment methods. As a first adjustment method, as shown in FIG. 7, the distance L1 between the reflection sensor 7 and the object 13 below the transport path 5 is made longer than the focal length L2 of the reflection sensor 7 so that there is no object 3 to be detected. In some cases, the structure is such that return light due to irregular reflection is eliminated as much as possible, and as an electric circuit configuration, the amplification gain after voltage conversion on the light receiving side 7b is fixed and the D /
By varying the voltage of the A converter 9 to change only the amount of light emission, there is a method of adjusting the output level during the passage of the object 3 so as to be sufficiently captured by a subsequent circuit such as an A / D converter. Was.

[0003]

However, in the above adjustment method, in order to eliminate the return light due to irregular reflection when there is no object, the object causing irregular reflection should be separated sufficiently from the sensor surface by a distance greater than the focal length. There is a restriction that it must be used, and there has been a problem that space efficiency is reduced. Next, as a second adjustment method, a method is known in which, in addition to using a D / A converter to vary the amount of light emission, an amplifier circuit capable of varying the gain on the light receiving side is known. That is, in this method, as a consideration for diffuse reflection, the output level due to diffused light when there is no detection object is:
The light emission amount is kept close to zero by holding down the light emission amount until the light receiving element enters the cutoff region, and the output level during the passage of the detection object is ensured by increasing the gain on the light receiving side. According to this method, since the light emission amount is suppressed so that the output level due to the irregularly reflected light becomes zero, even if the gain on the light receiving side is increased, the output level does not increase because the light receiving element is in the cutoff region when there is no detection object even when there is no detection object. . Therefore, it is not necessary to increase the distance L1 between the light reflection sensor 7 and the object 13, but the following problems occur. That is, for example, in applications where a plurality of passing points are detected, a plurality of the light reflection sensors are required. In this case, however, the number of circuits that can vary the gain on the light receiving side is required. In general, a variable resistor is used to change the gain. In this case, however, it takes time to adjust the variable resistor by the number of sensors, resulting in an increase in cost. In addition, there is a risk that the S / N ratio is lowered to decrease the amount of light emission extremely and increase the gain on the light receiving side, thereby deteriorating the detection performance. The present invention has been made in view of the above circumstances, and provides a method of adjusting a light reflection sensor in an object passage detection device capable of realizing highly reliable object passage detection without incurring cost. is there.

[0004]

In order to achieve the above object, the present invention relates to a method for adjusting a light reflection sensor in an object passage detection device for detecting the passage of a detected object such as a coin using a light reflection sensor. The first detection output level V1 of the amount of light received by the light receiving element when the object to be detected is detected and the second detection output level V2 of the amount of light received by the light receiving element when the object to be detected is not detected. Is measured while changing the amount of light emitted from the light emitting element of the optical sensor, and the difference V1 -V2 between the first detection output level and the second detection output level is obtained. The light emission when the difference becomes maximum is obtained. It is characterized in that the amount is an adjustment value.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on illustrated embodiments. FIG. 1 is a schematic configuration diagram of an embodiment of an object passage detection device according to the present invention. As shown in FIG. 1, the object passage detection device includes the above-described clearance 1 of a conveyance path 5 for a detected object 3 such as a coin having a clearance 1 at a predetermined interval.
A light reflection sensor 7 having a light emitting element 7a and a light receiving element 7b is disposed above the light emitting element 7a, a D / A converter 9 for adjusting the light emitting amount is provided on the light emitting element 7a side, and the light receiving amount is provided on the light receiving element 7b side. Is provided with a voltage detector 11 for detecting the output level. And the above D
The A / A converter 9 and the voltage detector 11 are connected to adjustment control means for adjusting the light reflection sensor 7 described later. The operation of the object passage detection device is as follows. When the detected object 3 passes through the gap 1 on the transport path 5 in a state where a predetermined amount of light is emitted from the light emitting element 7a of the light reflection sensor 7, the light receiving element The amount of light received by 7b changes. That is, when the detected object 3 is not present in the gap 1, the amount of received light is small, and the output level is also small. Conversely, when the detected object 3 is in the gap 1, the amount of received light increases, and the output level also increases. Therefore, if the increased output level is detected by the voltage detector 11 of the light receiving element 7b, the passage of the detected object 3 can be detected. Next, a method for adjusting the light reflection sensor 7 in the object passage detection device, which is the gist of the present invention, will be described. The method of adjusting the light reflection sensor 7 is performed by the adjustment control means 12, and the output level of the detection with and without the coin is measured while changing the amount of light emission. The maximum value of the difference V1-V2 between the output level V1 when there is no coin and the output level V2 when there is no coin is detected, and the light emission amount at that time is used as an adjustment value.

FIG. 2 is a flowchart of a method for adjusting the light reflection sensor 7 shown in FIG. In step 101 of FIG. 2, the light emitting element 7a of the light reflection sensor 7
By adjusting the D / A converter 9 on the side of the light emitting element 7a
In step 103, when there is a coin directly below the light reflection sensor 7 (in a state where the coin is detected) at the minimum light emission amount, the first light emission amount is proportional to the light reception amount by the light receiving element 7b. Of the light receiving element 7 in step 105 when there is no coin immediately below the light reflection sensor 7 at the minimum light emission amount (in a state where no coin is detected).
A second output level V2 is measured in proportion to the amount of light received by b. Next, at step 107, the D / A converter 9 is adjusted to gradually increase the light emission amount from the light emitting element 7a. At step 109, it is determined whether or not the light emission amount is the maximum, and the light emission amount becomes maximum. The measurement processing in steps 103, 105, and 107 is continued until the measurement result is stored in the storage unit of the adjustment control unit 12. FIG. 3 shows a plot of the measurement results in steps 103 and 105 to form a graph. As is clear from this figure, when there is a coin, the output level of the light receiving element is saturated and becomes almost constant even if the light emission amount is increased from the value indicated by the dotted line in the figure, whereas when there is no coin, It can be understood that the output level of the light receiving element increases almost linearly in accordance with the light emission amount, and it is not necessary to simply increase the light emission amount. Therefore, when it is determined in step 109 that the light emission amount has reached the maximum, the process proceeds to the next step 111, and there is no case where there is a coin immediately below the light reflection sensor 7 due to the change in the stored light emission amount. The difference (V1 -V2) between the above output levels and the case is obtained, and in step 113, the light emission amount A at the time when the difference between the first and second output levels (V1 -V2) is maximum is obtained (FIG. 4), the light emission amount when the difference between the output levels is maximum is adopted as the adjustment value, and is used as the light emission amount of the light emitting element 7a.

Next, a brief description will be given of a money handling apparatus in which the object passage detecting device having the adjusted light reflection sensor 7 is used. FIG. 5 is a schematic configuration diagram of a transport unit of a money handling apparatus in which the object passage detection device is used.
As shown in FIG. 5, sorting holes 15a and 15b whose outer diameters increase in order from the right are opened on the transport path 13, and when coins 17 are transported from the right to the left on the transport path 13, the outside of the holes is formed. The coins that have fallen into the first sorting hole 15a having a diameter larger than the diameter or the next larger sorting hole 15b are deposited on the tank 19. A light reflection sensor 7 for detecting the passage of coins is provided between the sorting holes 15a and 15b, and it is checked whether correct sorting has been performed. There is a gap 1 in the transport path below the light reflection sensor 7, and when there is no coin, the emitted light enters the lower part of the transport path through this hole. Although there is a return light even when there is no coin due to the irregular reflection object 19 at the lower part of the transport path, since the following circuit configuration and adjustment are performed, even if there is a return light when there is no coin, when there is a coin, Are sufficiently detectable. In general, the light emission amount of an optical sensor decreases due to deterioration with time. However, in the adjustment method according to the present invention, when the level of the light-receiving element 7b is almost the same as the saturation level, the first light emission is rapidly reduced due to the deterioration of the light emission amount.
And the difference (V1 -V2) between the second output levels decreases. Therefore, if the adjustment method according to the present invention is performed once a week or once a month using the same coin and the adjustment value is updated and learning is performed, it is possible to more reliably prevent the adverse effect such as the deterioration of the light emission amount. Further, a variable amplifying means is provided at the output of the light receiving element, and the flowchart of FIG. 2 is implemented at a predetermined amplification rate. Then, the flowchart of FIG. If the D / A converter and the variable amplifying means are set so that the maximum output level difference can be obtained by comparison, it will be useful in compensating for the deterioration with time of the optical sensor.

[0008]

As described above, according to the present invention, the output level of the detection with and without the coin is measured while changing the light emission amount in the light reflection sensor, and the output level of the coin is detected. Since the maximum value of the difference V1-V2 between the output level V1 and the output level V2 when no coin is present is detected and the light emission amount at that time is used as an adjustment value, a reliable object can be obtained without cost. Passage detection can be realized

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of an object passage detection device according to the present invention.

FIG. 2 is a flowchart of a method for adjusting the light reflection sensor 7 shown in FIG.

FIG. 3 is a graph showing a change in a detection output level in a case where curing is performed and in a case where curing is not performed with respect to a change in light emission amount.

FIG. 4 is a graph showing a change in a difference in detection output level between a case where curing is performed and a case where curing is not performed with respect to a change in light emission amount.

FIG. 5 is a schematic configuration diagram of a transport unit of the money handling apparatus in which the object passage detection device is used.

FIG. 6 is a schematic configuration diagram of an object passage detection device using a light reflection sensor.

FIG. 7 is a schematic configuration diagram of an object passage detection device using a conventional light reflection sensor.

[Explanation of symbols]

1: gap, 3: detected object, 5, 13: transport path, 7:
Light reflection sensor, 7a ... light emitting element,
7b: light receiving element, 9: D / A converter,
11 ... voltage detector, 15 ... distribution hole,
17 ... coin 19 ... tank,

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Claims (1)

[Claims] 1. A method for adjusting a light reflection sensor in an object passage detection device for detecting the passage of a detected object such as a coin using a light reflection sensor, the method comprising the steps of: The amount of light emitted from the light emitting element of the optical sensor is changed between the first detected output level V1 of the amount of received light and the second detected output level V2 of the amount of light received by the light receiving element when the object to be detected is not detected. The object passing is characterized by determining the difference V1 -V2 between the first detection output level and the second detection output level, and using the light emission amount when the difference becomes maximum as an adjustment value. How to adjust the light reflection sensor in the detection device.