JP2005284391A - Adjusting device and method for optical sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dispense with a test piece for adjusting an optical sensor in shipment while requiring no cost in holding characteristics after shipment. <P>SOLUTION: A light emitting element 2 of the optical sensor 1 is connected to a discrimination control circuit 10 through a D/A converter 4, and a light receiving element 3 is connected to the discrimination control circuit 10 through an amplifier 5 and an A/D converter 7. When a power supply is switched on, the discrimination control circuit 10 first sets the amplifier to a small amplification factor without the test piece in an adjusting mode and sets the output of the light emitting element 2 so that an input level from the light receiving element becomes a reference value set beforehand within an identification level range, and then changes to an identification mode and sets the amplifier to a large amplification factor so that the input level to the discrimination control circuit in identifying bills becomes a median value in the identification level range. Since this processing is carried out every input of power, there is no need to store a target output level for correction after shipment in an external storage device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an adjustment device and an adjustment method for an optical sensor that automatically adjusts an output level of an optical sensor in a characteristic determination device that distinguishes characteristics of an object from an output of the optical sensor such as a bill validator.

In the banknote discriminator, while the banknote inserted from the banknote slot is being transported, the optical characteristic of the banknote, for example, the degree of light transmission, is detected and discriminated from the output of the optical sensor arranged at a predetermined position, and the discrimination control The circuit determines the authenticity of the bill.
Conventionally, the output of the light receiving element is amplified by an amplifier so that the light receiving output of the light receiving element that has received the light transmitted through the bill to be detected becomes an intermediate value suitable for the authenticity determination of the banknote in the discrimination level range of the discrimination control circuit. It is configured to amplify and input to the discrimination control circuit.

  For example, a light-emitting diode is used as a light-emitting element as a main part of an optical sensor, and a phototransistor and a photodiode are used as a light-receiving element. However, output characteristics of these elements vary due to manufacturing errors, and the output of the light-emitting element And the output of the light receiving element rarely match each product. In addition, the characteristics change due to adhesion of dirt and aging due to use. There is a problem that it takes time to arrange output characteristics at the time of shipment, and to correct characteristic changes due to aging.

As a countermeasure for this problem, for example, there is a correction device disclosed in Japanese Patent Application Laid-Open No. 8-69550.
This is to manually switch between the setting mode and the normal mode. In the setting mode, it is determined whether or not the light reception output that enters the discrimination control circuit from the light receiving element is the same as the predetermined level. If the light reception output is different, the light emission output of the light emitting element is increased or decreased to match the light reception output to the predetermined level. As a result, the characteristics are uniform for variations due to manufacturing errors at the time of shipment or the like. Then, the instruction value of the light emission output at this time is stored in an external storage device such as an EEPROM.

In the normal mode, the instruction value of the light emission output stored in the external storage device is written in the RAM built in the discrimination control circuit, and based on this, the light emitting element is caused to emit light, and the processing is started, while also stored in the external storage device The target output level and the received light output are compared, and the light output of the light emitting element is increased or decreased so that the received light output entering the discrimination control circuit matches the target output level. As a result, automatic correction for dirt and other secular changes is performed.
JP-A-8-69550

However, when there is no bill between the light emitting element and the light receiving element, the light reception output amplified by the amplifier and input to the discrimination control circuit exceeds the discrimination level range in the discrimination control circuit, and it is difficult to accurately identify the light reception output. Become. Therefore, in the adjustment at the time of shipment by the setting mode, a test piece having a standard transmittance is arranged between the light emitting element and the light receiving element, and the received light output entering the discrimination control circuit becomes a predetermined intermediate value that can be easily identified. The light emission output of the light emitting element is set to.
Therefore, it is essential to use a test piece, and the setting mode and the normal mode must be switched manually, and it has not yet been solved.

In addition, there is an advantage that the automatic correction can automatically cope with the characteristic fluctuation of the optical sensor after shipment of the banknote discriminator, but the target output level that is the reference for correction is stored and held for a long period of time. An external storage device such as an EEPROM is required. Also, the instruction value of the light emission output set during the adjustment work must be stored and held in the external storage device. Therefore, there is a problem that the cost is increased.
An object of the present invention is to provide an optical sensor adjustment apparatus and method that does not require a test piece for adjustment at the time of shipment and that does not cost costs for maintaining characteristics after shipment.

  Therefore, the present invention provides an amplifier that amplifies the output of the light receiving element between the light receiving element and the discrimination control circuit, and the discrimination control circuit includes a light emission control unit that controls the output of the light emitting element, and an amplifier control unit that controls the amplifier. And the discrimination control circuit has a predetermined gain in which the amplification factor of the amplifier is a first amplification factor and the input level from the light receiving element to the discrimination control circuit is set within the discrimination level range of the discrimination control circuit. The adjustment mode for setting the output of the light emitting element so as to be the reference value, the output of the light emitting element as a value set in the adjustment mode, and the amplification factor of the amplifier as a second amplification factor larger than the first amplification factor, The identification mode for inputting the output of the light receiving element to the discrimination control circuit is sequentially executed.

In the adjustment mode, the output of the light emitting element is set so that the input level from the light receiving element becomes the reference value within the discrimination level range of the discrimination control circuit, so the input level is the reference value without having to reduce the light receiving output by the test piece. It is easy to determine whether or not it matches, and the output of the light emitting element can be adjusted accurately.
In the identification mode, the output of the light receiving element is amplified with a larger amplification factor than in the adjustment mode, so that the input level to the discrimination control circuit when the object is placed between the light emitting element and the light receiving element can be easily discriminated. Can be within the level.
Since the adjustment mode and the identification mode are automatically and sequentially executed every time the power is turned on, there is no need to store and hold the output value of the light emitting element set in the adjustment mode, and the target output for light reception Since there is no need to store and hold the level, an external storage device is also unnecessary.

Next, an embodiment of the present invention will be described.
FIG. 1 is a block diagram showing the configuration of the embodiment.
An optical sensor 1 is composed of a light emitting element 2 made of a light emitting diode and a light receiving element 3 made of a phototransistor or a photodiode.
The light emitting element 2 is connected to the discrimination control circuit 10 via the D / A converter 4.
The discrimination control circuit 10 includes a RAM 11, a light emission control unit 12, and an amplifier control unit 13.
The D / A converter 4 turns on the light emitting element 2 based on the digital output from the light emission control unit 12 that indicates the light emission level. The instruction value of the light emission level that the light emission control unit 12 instructs the D / A converter 4 is stored in the RAM 11.

The light receiving element 3 is connected to the discrimination control circuit 10 via the amplifier 5 and the A / D converter 7. The amplifier 5 amplifies the output of the light receiving element 3, and the A / D converter 7 converts the output of the amplifier 5 into digital data and inputs it to the discrimination control circuit 10.
An amplification factor switching circuit 6 is connected to the amplifier 5, and the amplification factor switching circuit 6 switches the amplification factor of the amplifier 5 based on a command from the amplifier control unit 13.

Next, the adjustment control process in the above configuration will be described with reference to the flowchart of FIG.
When the power is turned on, first, at step 101, the discrimination control circuit 10 enters the adjustment mode, sends a command from the amplifier control unit 13 to the amplification factor switching circuit 6, and sets the amplification factor of the amplifier 5 for adjustment. The adjustment amplification factor as the first amplification factor is, for example, 1 (times).

In the next step 102, the discrimination control circuit 10 outputs an instruction to increase the light emission level of the light emitting element 2 by one level from the light emission control unit 12 to the D / A converter 4. In step 103, the input level, that is, the amplifier 5 is set. It is checked whether or not the output of the light receiving element 3 that has passed has reached a predetermined reference value.
While the input level does not reach the reference value, steps 102 and 103 are repeated. When the input level reaches the reference value, the discrimination control circuit 10 stores the light emission level instruction value in the RAM 11 and proceeds to step 104.

In step 104, the discrimination control circuit 10 enters an identification mode, sends a command from the amplifier control unit 13 to the amplification factor switching circuit 6, and switches the amplification factor of the amplifier 5 for identification. The amplification factor for identification as the second amplification factor is, for example, 10 (times). The amplification factor for identification is set so that the input level when the light from the light emitting element 2 corresponding to the reference value for adjustment passes through the banknote to be identified is substantially in the middle of the identification level range of the discrimination control circuit 10. Set as magnification to amplify to value.
Thereafter, the power supply is turned off to wait until the bill is passed through the optical sensor 1.

FIG. 3 shows an example of the adjustment result by the above-described control process when the discrimination level range of the discrimination control circuit 10 is 256 steps from 0 to 255. The reference value for adjustment is set to 80 ± 0.4.
In the optical sensor of Example 1, the sensor coefficient obtained by making the relationship between the output of the light receiving element 3 and the output of the light emitting element 2 dimensionless was 0.6. The light emission control unit 12 of the discrimination control circuit 10 instructs the D / A converter 4 to make the input level input from the light receiving element 3 to the discrimination control circuit 10 with the amplification factor = 1 coincide with the reference value. Was increased to 133. Thereby, the output (adjustment setting value) of the light receiving element 3 is 79.8 (= 0.6 × 133).

When the identification mode is set at step 104, the amplification factor of the amplifier 5 is switched to 10, so that the input level (identification set value) inputted from the light receiving element 3 to the discrimination control circuit 10 becomes 798. When a bill enters between the light emitting element 2 and the light receiving element 3 of the optical sensor 1, the input level input to the discrimination control circuit 10 becomes an intermediate value within the discrimination level range 0 to 255.
The same applies to Examples 2 to 3 having different sensor coefficients.

As described above, in the present embodiment, when the power is turned on, the input level that enters the discrimination control circuit 10 is set in advance within the discrimination level range in the adjustment mode before the bill is conveyed to the optical sensor 1. The output (light emission level) of the light emitting element 2 is set so that the reference value is set, and then the mode is changed to the identification mode, and the input level to the discrimination control circuit 10 at the time of banknote discrimination becomes an intermediate value of the discrimination level range. Thus, the amplification factor of the amplifier 5 is switched and fixed to a predetermined constant value. Since the indication value of the light emission level set in the adjustment mode is held in the RAM 11 built in the discrimination control circuit, the output of the light emitting element 2 is held at a constant value set in the adjustment mode until the power is turned off.
This process is executed every time the power is turned on, and while the power is turned on, the light emission level of the light emitting element 2 is always maintained at a level corresponding to the reference value.

The embodiment is configured as described above, and the discrimination control circuit 10 controls the light emission control unit 12 that controls the output of the light emitting element 2 and the amplifier 5 provided between the light receiving element 2 and the discrimination control circuit 10. And an adjustment unit that sets the output of the light emitting element 2 so that the input level from the light receiving element 3 to the discrimination control circuit 10 becomes a predetermined reference value set within the discrimination level range of the discrimination control circuit. The mode and the identification mode for amplifying the output of the light receiving element 3 at the amplification factor for identification under the set output of the light emitting element 2 are sequentially executed.
Thereby, first, in the output setting of the light emitting element 2, since the reference value is within the identification level range of the discrimination control circuit 10, it can be adjusted easily and accurately without using a test piece, and the output of the light receiving element 3 at the time of discrimination. As a result of this amplification, it can be within the discrimination level range of the discrimination control circuit 10 and discrimination becomes easy.

Since the adjustment mode and the identification mode are automatically executed every time the power is turned on, there is no need for an external storage device for storing and holding the target output level as in the prior art, and an appropriate light receiving output is always obtained. be able to.
In particular, each time the power is turned on, the input level to the discrimination control circuit 10 is set to the reference value while increasing the output of the light emitting element 2 by one level. There is no need to store it in a storage device.

  In the embodiment, the light receiving element 3 of the optical sensor 1 has been described as receiving light transmitted through the bill. However, the present invention is not limited to this, and the optical sensor that receives light reflected by the bill is also used. The same applies, and the amplification factor of the amplifier may be determined in accordance with the application mode.

It is a block diagram which shows the structure of embodiment. It is a flowchart which shows the flow of adjustment control in embodiment. It is a figure which shows the example of an adjustment result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical sensor 2 Light emitting element 3 Light receiving element 4 D / A converter 5 Amplifier 6 Amplification rate switching circuit 7 A / D converter 10 Discrimination control circuit 11 RAM
12 Light emission control unit 13 Amplifier control unit

Claims (2)

Optical sensor adjusting device in a characteristic discriminating apparatus comprising: an optical sensor including a light emitting element and a light receiving element; and a discrimination control circuit for discriminating characteristics of an object disposed between the light emitting element and the light receiving element from the output of the optical sensor Because
An amplifier for amplifying the output of the light receiving element is provided between the light receiving element and the discrimination control circuit,
The discrimination control circuit includes a light emission control unit that controls an output of the light emitting element, and an amplifier control unit that controls the amplifier.
The discrimination control circuit sets the amplification factor of the amplifier to a first amplification factor by the amplifier control unit, and an input level from the light receiving element to the discrimination control circuit by the light emission control unit is a discrimination level range of the discrimination control circuit. An adjustment mode for setting the output of the light emitting element so as to be a predetermined reference value set in the output, and an output of the light emitting element as a value set in the adjustment mode, and the amplification factor of the amplifier is set to the first amplification An apparatus for adjusting an optical sensor, which sequentially executes an identification mode in which an output of the light receiving element is input to a discrimination control circuit as a second amplification factor larger than the rate. Optical sensor adjustment method in characteristic discriminating apparatus having optical sensor including light emitting element and light receiving element, and discriminating control circuit for discriminating characteristic of object arranged between light emitting element and light receiving element from output of optical sensor Because
First, the output of the light emitting element is set so that the input level from the light receiving element becomes a predetermined reference value set within the identification level range of the discrimination control circuit, and then the light emitting element of the set light emitting element is set. A method for adjusting an optical sensor, wherein the output of the light receiving element is amplified with a predetermined amplification factor under an output and is input to the determination control circuit.

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