JPH10221467A - Optical sensor output setting circuit and its setting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily conduct power control. SOLUTION: In an optical sensor output setting circuit 1 with an optical sensor 8 receiving the light of a luminous element 4 with a light reception element 9 and detecting the existence of a detected body 12 put in between the luminous element 4 and the light reception element 9, the first resistor 5 and the second resistor 6 regulating the current flowing in the luminous element 4 are connected in parallel to the luminous element 4, and simultaneously the connection and separation of the second resistor 6 to the current path flowing in the luminous element 4 is made free by connecting a switch means 7 to the second resistor 6 and the value of a light reception resistor 10 regulating the current flowing in the light reception element 9 is set in the state the second resistor 6 is separated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical sensor output setting circuit and a setting method thereof. More specifically, the present invention relates to a method for setting a light-receiving resistance value that defines an output in an optical sensor output setting circuit and an improvement in the setting circuit.

[0002]

2. Description of the Related Art As shown in FIG. 4, an output setting circuit 101 of an optical sensor for detecting a card provided in a card reader or the like includes a light emitting element 102 such as a light emitting diode and a light receiving element 103 such as a phototransistor. Optical sensor 104
The light emitting element 102 and the light receiving element 103
The object to be detected 105 such as a card is interposed between them and shields light to detect the object to be detected 105. But,
The sensitivity of each element changes due to a difference in sensitivity of each element or a variation in assembly, and a difference may occur in the output of the optical sensor 104. Therefore, in order to correct the difference, some adjustment is required for setting the output of the optical sensor 104.

Conventionally, a current flowing through the light receiving element 103 which has received light (hereinafter, referred to as “light receiving element current”) is measured, and a load resistor 106 having a value corresponding to the magnitude of the light receiving element current is set to set the optical sensor 104. Output sensitivity was set. The load resistor 106 is a resistor that is connected to the light receiving element 103 and defines the value of the light receiving element current (hereinafter, referred to as “light receiving resistance”). When a variable resistor is used as the light-receiving resistor 106, the resistance value is changed. When a fixed resistor is used, an appropriate resistor value is selected, and the output is set by soldering or the like.

On the other hand, if the surface of the light-emitting element 102 becomes dirty, the amount of light emission decreases, and the light-receiving element current decreases accordingly. It is necessary to consider the decrease in the light receiving element current due to contamination. In order to be able to detect the presence or absence of a card using the optical sensor 104 until the light receiving element current decreases to, for example, １ ／ of the maximum current value, the light receiving current value is set to the minimum value of 4 which can be detected by the card. The value of the light receiving resistor 106 is set so as to be twice as large.

[0005]

However, when a variable resistor is used as the light receiving resistor 106, the resistance value must be adjusted while measuring the light receiving element current. It takes time and effort. When a fixed resistor is used, it is necessary to select and mount a resistor suitable for the magnitude of the light receiving element current while measuring the light receiving element current for each output setting circuit 101, which is more troublesome than a variable resistor. Take it.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical sensor output setting circuit which can easily adjust the output and a method of setting the same.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a light receiving element receives light from a light emitting element, and an object to be detected interposed between the light emitting element and the light receiving element. In the optical sensor output setting circuit in the optical sensor that detects the presence of, the first resistor and the second resistor that define the current flowing through the light emitting element are connected in parallel to the light emitting element, and the second resistor is connected to the second resistor. A switch means is connected so that the second resistor can be freely inserted into and separated from a current path flowing through the light emitting element, and a light receiving resistance value defining a current flowing through the light receiving element is set in a state where the second resistor is disconnected. ing.

Accordingly, when the second resistor is disconnected, the current flowing through the light emitting element decreases, and the light emission amount of the light emitting element decreases.
This makes it possible to set the light receiving resistance value by simulating a state in which the light emission amount of the light emitting element is reduced due to dirt or the like. Also,
The insertion and disconnection of the second resistor into and out of the current path can be instantaneously and easily operated by the switch means. Further, the current flowing through the light emitting element can be freely adjusted by a combination of the resistance values of the first resistor and the second resistor.

In the optical sensor output setting circuit according to the second aspect, the object to be detected is a card, and the optical sensor detects an end face of the card. Therefore, in the light sensor output setting circuit of the card reader having the light sensor, the light receiving resistance value can be set by simulating the state where the light sensor is dirty.

According to the third aspect of the present invention, the light of the light emitting element is received by the light receiving element, and the light in the optical sensor is configured to detect the presence of the object interposed between the light emitting element and the light receiving element. In the sensor output setting method, a first resistor and a second resistor defining a current flowing through the light emitting element are connected in parallel to the light emitting element, and a switch is connected to the second resistor to emit light from the second resistor. After the insertion and removal of the second resistor from the light-emitting element is determined, the value of the light-receiving resistor that defines the current flowing through the light-receiving element is determined. The presence of an object to be detected interposed between the light emitting element and the light receiving element is detected while being inserted into the current path flowing through the light emitting element.

Therefore, when the second resistor is disconnected, the current flowing through the light emitting element decreases, and the light emission amount of the light emitting element decreases.
Thus, it is possible to simulate a state in which the light emission amount of the light emitting element is reduced, and to set the light receiving resistance value. When the setting of the light-receiving resistance value is completed, a state in which the presence or absence of the object to be detected can be detected by inserting a second resistor.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on an example of an embodiment shown in the drawings.

FIG. 1 shows an embodiment of an optical sensor output setting circuit according to the present invention. The optical sensor output setting circuit here is used for detecting the end face of a card in a card reader, for example.

The light sensor output setting circuit 1 includes a light emitting side circuit 2 and a light receiving side circuit 3. The light emitting side circuit 2 includes a light emitting element 4 and a first resistor 5 always connected to the light emitting element 4.
A second resistor 6 connected in parallel to the first resistor 5;
A switch means for interrupting the current flowing through the second resistor. The light receiving side circuit 3 includes a light receiving element 9, a light receiving resistor 10 for defining a current value of a light receiving element current flowing through the light receiving element 9, and a voltmeter 11. Light emitting element 4
The light sensor 8 is configured such that the light receiving element 9 receives the light emitted by the light sensor 8. Also, the light receiving side circuit 3
A detector (not shown) for detecting the output from the device is attached.

The light emitting element 4 is, for example, a light emitting diode. When the value of the current flowing through the light emitting element 4 changes, the light emission amount of the light emitting element 4 also changes with the change.

The first resistor 5 is connected to the light emitting element 4 and regulates a current flowing through the light emitting element 4. No switching means is particularly provided in the path of the first resistor 5, and a current always flows while a voltage is applied.

The second resistor 6 is connected in parallel with the first resistor 5. Switch means 7 is attached to the second resistor 6, and the current flowing through the second resistor 6 is interrupted by opening and closing the switch means 7. And
When the switch means 7 is closed, the second resistor 6 can be inserted into the current path flowing through the light emitting element 4, while when the switch means 7 is opened, the second resistor 6 can be disconnected from the current path. When the second resistor 6 is disconnected, the current flowing through the light emitting element 4 decreases, and the light emission amount decreases.

The switch means 7 can freely switch the current flowing through the second resistor 6, and uses, for example, the transistor shown in FIG. However, the present invention is not limited to this, and a switch, a relay, or another switching element shown in FIG. 2 may be used.

The ratio between the magnitudes of the resistance values of the first resistor 5 and the second resistor 6 is set, for example, to 3: 1. By doing so, the ratio of the magnitude of the resistance value of the combined resistor to the resistance value of the first resistor 5 is 1: 4. Therefore, the current flowing through the light emitting element 4 is different between when the switch means 7 is closed and when the switch means 7 is opened. The size ratio becomes 4: 1 and the light emission amount of the light emitting element 4 changes similarly. However, the ratio of the magnitudes of the resistance values is not limited to this, and may be changed based on how much the light emission amount is changed.

The light receiving element 9 is, for example, a phototransistor that senses light emitted from the light emitting element 4. A voltage of, for example, 5 V is supplied to the light emitting side circuit 2 and the light receiving side circuit 3. When the light receiving element 9 receives light, a light receiving element current flows according to the amount of received light. The light emitting element 4 and the light receiving element 9 are attached with a card path of a card reader interposed therebetween.

The light receiving resistor 10 is connected to the light receiving element 9. By changing the magnitude of the resistance value of the light receiving resistor 10, the output of the light receiving side circuit 3 is changed, and a desired output value is set.

The voltmeter 11 is attached to the light receiving side circuit 3 and is used for measuring an output voltage.

According to the optical sensor output setting circuit 1 configured as described above, the output of the optical sensor 8 is set as follows. Here, a description will be given of a case where the card can be detected until the light emitting element 4 becomes dirty and the light emission amount becomes 1/4 of the normal light emission amount.

First, with the second resistor 6 separated from the light emitting element 4, the value of the light receiving resistor 10 for defining the current flowing through the light receiving element 9 is determined. When the second resistor 6 is separated from the light emitting element 4, the light emission amount of the light emitting element 4 becomes 1 / the normal amount.
Decrease to 4. In this state, the value of the light receiving resistor 10 is adjusted while checking the voltmeter 11 so that the output voltage becomes 2.5 V, for example.
Set to be.

Then, with the second resistor 6 inserted in the current path flowing through the light emitting element 4, the presence of an object to be detected such as a card interposed between the light emitting element 4 and the light receiving element 9 is detected. That is, when the switch means 7 is closed, the current flowing through the light emitting element 4 is defined by the combined resistance of the first resistor 5 and the second resistor 6, and the light emitting amount of the light emitting element 4 is the normal light emitting amount (dirt of the light emitting element 4). The light emission amount has a margin in consideration of the above. If the optical sensor 8 is incorporated in the card reader in this state, the card can be detected with a sufficient amount of light.

Light emitted from the light emitting element 4 toward the light receiving element 9 is blocked by the card while the card passes. Therefore, light is interrupted depending on the presence or absence of the card, and accordingly, the current of the light receiving side circuit 3 is also interrupted. The presence or absence of the card converted to the output current of the light receiving side circuit 3 is detected by the detector.

In the optical sensor output setting circuit 1 set as described above, it is possible to detect a card until the light emission amount of the light emitting element 4 becomes 1/4 of a normal amount. The extent to which detection is possible until the amount of light emission decreases can be appropriately changed by selecting the resistance ratio of the first resistor 5 and the second resistor 6.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention. For example, in the present embodiment, the first resistor 5 and the second resistor 6 are attached to the light emitting side circuit 2 in parallel so that the output in the light receiving side circuit 3 can be easily set, but as shown in FIG. The two resistors 5 and 6 may be attached in series. In this case, the first resistor 5 is always connected to the light emitting element 4 and the second resistor 6 is connected to the first resistor 5 using the switch means 7. Here, if the ratio of the resistance values of the first resistor 5 and the second resistor 6 is set to, for example, 1: 3, the combined resistance when the switch means 7 is switched to the second resistor 6 becomes the first resistor. This is four times as large as the resistance 5, and the light emission amount of the light emitting element 4 can be reduced to 1/4 before switching the switch means 7.

As another means, the voltage source of the light emitting side circuit 2 or the light receiving side circuit 3 is reduced to, for example, 1/4 to reduce the light receiving element current, thereby simulating a dirty state of the light emitting element 4 and the like. Things are conceivable. The same effect as the present invention can be obtained by this means.

[0030]

As is apparent from the above description, the light sensor output setting circuit according to the first aspect of the present invention comprises a light emitting element in parallel with a first resistor and a second resistor defining a current flowing through the light emitting element. And a switch means connected to the second resistor so that the second resistor can be freely inserted into and disconnected from a current path flowing through the light emitting element, and the light receiving resistance value defining the current flowing through the light receiving element is set to the second value. Since the setting is made in a state where the second resistor is separated, when the second resistor is separated, the current flowing through the light emitting element decreases, and the light emission amount of the light emitting element decreases. This makes it possible to set the light receiving resistance value by simulating a state in which the light emission amount of the light emitting element is reduced due to dirt or the like. Further, the insertion and disconnection of the second resistor from / to the current path can be instantaneously and easily operated by the switch means. Further, the current flowing through the light emitting element can be freely adjusted by a combination of the resistance values of the first resistor and the second resistor. Therefore, the output can be easily adjusted.

In the optical sensor output setting circuit according to the second aspect of the present invention, the object to be detected is a card, and the optical sensor detects an end face of the card. Therefore, in the optical sensor output setting circuit of the card reader including the optical sensor, the light receiving resistance value can be set by simulating the dirty state of the optical sensor, and the output can be easily adjusted.

According to a third aspect of the present invention, a first resistor and a second resistor defining a current flowing through the light emitting element are connected in parallel to the light emitting element.
The switch means is connected to the second resistor to allow the second resistor to be freely inserted into and separated from the current path flowing to the light emitting element, and the current flowing to the light receiving element in a state where the second resistor is separated from the light emitting element. After setting the specified light-receiving resistor value,
Since the presence of the object to be detected interposed between the light emitting element and the light receiving element is detected while the second resistor is inserted in the current path flowing through the light emitting element, the light emitting element is disconnected when the second resistor is disconnected. The amount of light emitted from the light emitting element decreases due to a decrease in the flowing current. Thus, it is possible to simulate a state in which the light emission amount of the light emitting element is reduced, and to set the light receiving resistance value. Therefore, output adjustment can be easily performed. When the setting of the light-receiving resistance value is completed, a state in which the presence or absence of the object to be detected can be detected by inserting a second resistor.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an example of an embodiment of an optical sensor output setting circuit of the present invention.

FIG. 2 is a circuit diagram of a light emitting side circuit showing another embodiment of switch means.

FIG. 3 is a circuit diagram showing another embodiment of the light emitting side circuit of the present invention.

FIG. 4 is a circuit diagram showing a conventional optical sensor output setting circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical sensor output setting circuit 4 Light emitting element 5 First resistor 6 Second resistor 7 Switching means 8 Optical sensor 9 Light receiving element 10 Light receiving resistor 12 Object to be detected

Claims (3)

[Claims] 1. An optical sensor output setting circuit in an optical sensor configured to receive light of a light emitting element by a light receiving element and detect the presence of a detection target interposed between the light emitting element and the light receiving element. A first resistor and a second resistor that define a current flowing in the light emitting element are connected in parallel to the light emitting element, and a switch is connected to the second resistor so that the light emitting element of the second resistance is connected. An optical sensor output setting circuit, wherein insertion and separation into and from a current path flowing through the light receiving element can be freely performed, and a light receiving resistance value defining a current flowing through the light receiving element is set in a state where the second resistor is separated. . 2. The optical sensor output setting circuit according to claim 1, wherein the object to be detected is a card, and the optical sensor detects an end face of the card. 3. An optical sensor output setting method for an optical sensor in which light from a light emitting element is received by a light receiving element and the presence of an object to be detected interposed between the light emitting element and the light receiving element is detected. A first resistor and a second resistor that define a current flowing in the light emitting element are connected in parallel to the light emitting element, and a switch is connected to the second resistor so that the light emitting element of the second resistance is connected. The insertion and disconnection to the current path flowing to the freely, and the value of the light-receiving resistor that defines the current flowing to the light-receiving element in a state where the second resistor is separated from the light-emitting element, and then the second An optical sensor output setting method, comprising: detecting the presence of an object interposed between the light emitting element and the light receiving element while inserting a resistor into a current path flowing through the light emitting element.