JP2010272009A - Device for discriminating optical characteristic of paper sheets, design method therefor, and method for discriminating optical characteristic of paper sheets - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect optical characteristics of paper sheets by a simple configuration. <P>SOLUTION: A bill validator 20 includes an irradiation part 40 for radiating ultraviolet light, a visible light cut filter 50, an ultraviolet cut filter 60, and a detection unit 70 having a line-type light receiving element. The detection unit 70 includes a validating sensor 71 for receiving light which the ultraviolet cut filter 60 transmits and calibrating sensors 72 and 73 for receiving light which the ultraviolet cut filter 60 does not transmit. The bill validator 20 radiates light by the radiation part 40 without a bill Va on an optical path to read outputs of the validating sensors 71 and 72 and compares the outputs with initial output values of the validating sensors, which are stored in a memory upon shipping. After the light quantity of the irradiation part 40 or the like are controlled so that difference in the comparison falls within a prescribed range, bill validating processing is executed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for detecting optical characteristics of paper sheets.

  In financial institutions, automatic teller machines that can perform unattended deposit and withdrawal operations are widely used. In the automatic teller machine, a banknote discriminating apparatus is provided for determining the authenticity of banknotes to be handled, and the banknotes are irradiated with light to detect fluorescence and phosphorescence obtained by using the irradiated light as excitation light, or to reflect the irradiated light. The authenticity of the banknote is determined by identifying the transmission state or the transmission state. In such a banknote discriminating apparatus, the light quantity of the light source fluctuates due to the influence of the ambient temperature and aging deterioration. Therefore, it is necessary to correct the light quantity as necessary in order to keep accurate authenticity discrimination performance. For these reasons, various light quantity correction techniques have been developed (for example, Patent Document 1 and Patent Document 2 below).

  In Patent Document 1, an ultraviolet light receiving element for receiving ultraviolet light is provided at a location different from a fluorescence light receiving element that detects fluorescence obtained from paper sheets irradiated with ultraviolet light, and the ultraviolet light receiving element is detected. A technique for performing light amount correction using the result is disclosed. Moreover, in patent document 2, it arrange | positions in order of an ultraviolet light irradiation part, a banknote, and a reflecting plate, receives fluorescence with the fluorescence light receiving element provided in the same side as the ultraviolet irradiation part with respect to a banknote, and a banknote is arrange | positioned. A technique is disclosed in which an ultraviolet light receiving element that receives reflected light from a reflecting plate when not being provided is provided separately, and light amount correction is performed using the detection result of the ultraviolet light receiving element.

  However, in these technologies, it is necessary to arrange an independent individual ultraviolet light receiving element for monitoring the light amount deterioration of the ultraviolet light irradiation unit, and the number of parts for the light receiving element and a circuit for photoelectric conversion increases. However, the complexity and size of the equipment has become a problem. Further, the technology of Patent Document 2 is configured such that an ultraviolet light irradiation unit and a light receiving unit that receives ultraviolet light and fluorescent light are disposed to face each other, and the transmitted fluorescent light emission amount and the transmitted ultraviolet light amount of a paper sheet are identified. In this case, the optical path between the ultraviolet light irradiation unit and the light receiving element is blocked by the reflecting plate, and thus cannot be employed. Such a problem is not limited to the banknote discriminating apparatus, and is a problem common to various paper sheet optical property detection devices that detect optical characteristics of paper sheets such as banknotes, securities, and forms.

JP 2002-197506 A Japanese Patent Application Laid-Open No. 2003-0667805

  In consideration of at least a part of the above problems, the problem to be solved by the present invention is to accurately detect the optical characteristics of paper sheets with a simple configuration.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1] A paper sheet optical characteristic identification device for detecting optical characteristics of a paper sheet,
An irradiating unit for irradiating light;
A bandpass filter that is provided in a part of the optical path of the irradiation light irradiated by the irradiation unit and selectively transmits light of a specific wavelength;
A detection unit in which a plurality of light receiving elements for detecting light are arranged, the first light receiving element including at least one light receiving element that receives light transmitted through the band pass filter, and not transmitted through the band pass filter A detection unit including a second light receiving element composed of at least two light receiving elements that receive at least light of the path;
Secondary light obtained from the paper sheets disposed on the optical path of the irradiated light as excitation light using the irradiated light irradiated on the paper sheets, and transmitted through the bandpass filter. An identification unit for identifying optical characteristics of the paper sheet based on a detection result of the first light receiving element;
A controller that calibrates the detection result of the first light receiving element based on the detection result of the second light receiving element in a state where the paper sheet is not disposed on the optical path of the irradiation light; Paper sheet optical property identification device provided.

  The paper sheet optical characteristic identification device having such a configuration transmits the secondary light obtained by irradiating light to the paper sheet through the band-pass filter and based on the result detected by the first light receiving element. Identify the optical properties of Here, the control unit controls the light emission amount of the irradiation unit based on the detection result of the second light receiving element in a state where the paper sheet is not arranged on the optical path of the irradiation light, and / or The detection result of one light receiving element is corrected. Therefore, even if the amount of light varies due to the influence of ambient temperature or aging deterioration, the influence can be calibrated and the light-specific characteristics of paper sheets can be accurately identified. In addition, since a detection unit including a plurality of light receiving elements and including a first light receiving element and a second light receiving element is used, it is not necessary to separately arrange the first light receiving element and the second light receiving element. Therefore, the apparatus configuration can be simplified. Further, since the second light receiving element is composed of at least two light receiving elements, the reliability of the detection result of the second light receiving element can be improved. As a result, the control of the amount of light emitted by the control unit and the correction of the detection result can be performed with high accuracy, and the paper sheet identification accuracy can be improved.

Application Example 2 The control unit includes, as the calibration, control of the light emission amount of the irradiation unit, correction of the detection result of the first light receiving element, and adjustment of sensitivity of the first light receiving element. The paper sheet optical property identification device according to application example 1 that performs at least one.
The sheet optical characteristic identification device having such a configuration performs at least one of control of the light emission amount of the irradiation unit, correction of the detection result of the first light receiving element, and adjustment of the sensitivity of the first light receiving element. Even if the amount of light varies due to the influence of temperature or aging, the influence can be suitably calibrated, and the light-specific characteristics of the paper sheets can be accurately identified.

Application Example 3 The paper sheet optical characteristic identification device according to Application Example 1 or Application Example 2, in which the irradiation unit and the detection unit are arranged to face each other via the bandpass filter.
In the paper sheet optical property identification device having such a configuration, the irradiation unit and the detection unit are arranged to face each other, and therefore, compared with the case where the irradiation unit and the detection unit are arranged toward the same direction, The apparatus configuration can be simplified.

Application Example 4 The paper sheet optical property identification device according to any one of Application Examples 1 to 3, wherein the irradiation unit is a single light source.
The paper sheet optical property identification device having such a configuration can simplify the device configuration. In addition, since the second light receiving element is composed of at least two light receiving elements, it is verified whether or not the optical axis deviation of the single light source has occurred due to the difference in the output value of each of the second light receiving elements. can do. That is, when the optical axis deviation occurs in the manufacturing stage of the paper sheet optical characteristic identification device, the work for eliminating the optical axis deviation can be performed. Therefore, it is possible to provide a paper sheet optical property identification device with high identification accuracy.

Application Example 5 The paper sheet optical characteristic identification device according to Application Example 4, in which at least two light receiving elements constituting the second light receiving element include two light receiving elements arranged apart from each other.
In the paper optical characteristic identification device having such a configuration, when the optical axis shift of a single light source occurs, the output values of the second light receiving elements are likely to differ. That is, it is easy to grasp the optical axis deviation.

Application Example 6 The paper sheet optical characteristic identification device according to Application Example 5, in which at least two light receiving elements constituting the second light receiving element are arranged symmetrically with the optical axis of the irradiation light as an axis of symmetry. .
The paper optical characteristic identification device having such a configuration is easy to grasp the optical axis deviation because a difference occurs between the output values of the second light receiving elements arranged symmetrically when the optical axis deviation occurs.

Application Example 7 The paper sheet according to any one of Application Examples 4 to 6, wherein the second light receiving element is provided at a position farther than the first light receiving element with respect to the optical axis of the irradiation light. Optical characteristics identification device.
In the paper optical characteristic identification device having such a configuration, the detection result of the first light receiving element used by the identification unit detects light that has passed through the paper sheet and the bandpass filter, and the second result is used by the control unit. The detection result of the light receiving element detects light that does not pass through either the paper sheet or the bandpass filter. That is, generally, the output value of the second light receiving element is larger than that of the first light receiving element. Here, the second light receiving element is provided at a position farther from the optical axis of the irradiation light than the first light receiving element. That is, the second light receiving element is provided at a position where the optical distance from the irradiation unit is relatively long and the irradiation light is relatively attenuated. Therefore, the output levels of the first light receiving element and the second light receiving element can be made closer by moving the second light receiving element relatively away from the optical axis.

Application Example 8 Further, the optical axis shift of the irradiation light is detected based on the detection result of the second light receiving element in a state where the paper sheet is not disposed on the optical path of the irradiation light. The paper sheet optical characteristic identification device according to any one of Application Example 4 to Application Example 7, which includes an optical axis deviation detection unit.
The paper optical characteristic identification device having such a configuration can detect an optical axis shift based on the detection result of the second light receiving element in a state where the paper is not arranged on the optical path of the irradiation light. Therefore, it can be avoided that the optical axis is shifted in the manufacturing stage or at the time of use after shipment, that is, in a state where the accuracy of the control unit or the identification unit is lowered.

Application Example 9 The paper sheet optical characteristic identification device according to Application Example 8, wherein the control unit corrects a detection result of the first light receiving element based on a detection result of the optical axis deviation detection unit.
The paper optical characteristic identification device having such a configuration corrects the detection result of the first light receiving element based on the detection result of the optical axis deviation, so that the influence of the optical axis deviation is calibrated and the light of the paper sheet is calibrated. Another characteristic can be identified with high accuracy.

[Application Example 10] The paper sheet optical property identification device according to any one of Application Examples 1 to 3, wherein the irradiation unit includes a line in which a plurality of light sources are arranged in the arrangement direction of the light receiving elements. A paper sheet optical characteristic identification device, which is a light source, and wherein the band pass filter includes at least one slit in an arrangement direction of the light receiving elements.

  Since the paper optical characteristic identification device having such a configuration includes a line light source, it can irradiate light over a wide range and identify a wide range of paper sheets at a time as compared with a single light source. . In addition, since the bandpass filter includes at least one slit, for example, the second light receiving element can be arranged at both ends of the bandpass filter and the slit corresponding part. That is, the arrangement interval of the second light receiving elements can be reduced. Therefore, even if light source unevenness occurs in the arrangement direction of the light receiving elements of the detection unit due to a change in the light amount of each light source constituting the line light source, the influence can be suppressed. Moreover, according to the position of a detection part, based on the detection result of the 2nd light receiving element distribute | arranged to the said position, a calibration of a control part can be performed accurately.

Application Example 11 In the application examples 1 to 10, the control unit performs the calibration based on an output result of a light receiving element that is not adjacent to the first light receiving element among the second light receiving elements. The paper sheet optical characteristic identification device according to any one of the above.

  Based on the output result of the light receiving element that is not adjacent to the first light receiving element, that is, with the light receiving element in a location that is not affected by the light transmitted through the bandpass filter, Calibration can be accurately performed based on the output result.

Application Example 12 In any one of Application Examples 1 to 11, the control unit performs the calibration based on an output result of a light receiving element having a relatively large output value among the second light receiving elements. Or a paper optical characteristics identifying device.

  Since the paper optical characteristics identification device having such a configuration performs calibration based on the output result of the light receiving element having a relatively large output value, as a result, it is affected by the light transmitted through the bandpass filter, The output result of the light receiving element whose output is lowered is not used. Therefore, the same effect as in Application Example 10 is achieved.

Application Example 13 The control unit is a light receiving element provided at a position where, of the second light receiving elements, light transmitted through the band pass filter and light not transmitted through the band pass filter do not interfere with each other. 13. The paper sheet optical property identification device according to any one of application examples 1 to 12, wherein the calibration is performed based on the output result.
The paper sheet optical characteristic identification device having such a configuration also has the same effect as in Application Example 10 for the same reason.

[Application Example 14] The method for designing a paper sheet optical characteristic identification device according to any one of Application Examples 1 to 13, wherein the second light receiving element receives secondary light transmitted through the bandpass filter. If it is assumed that the second light-receiving element is disposed at a position where the detection level of the secondary light at the second light-receiving element is less than the detectable range, a design method for a paper sheet optical characteristic identification device .

  Since the paper optical characteristics identifying apparatus having such a configuration can design the output level of the second light receiving element to be low, the cost of the apparatus can be reduced. Further, if the first light receiving elements are arranged at all positions where the detection level of the secondary light is within a detectable range, a large number of first light receiving elements can be secured. As a result, optical characteristics of a wide range of paper sheets can be identified at the same time, and efficient identification can be performed.

The present invention can also be realized as a paper sheet optical property detection method shown in application example 15.
[Application Example 15] A paper sheet optical property detection method for detecting an optical property of a paper sheet, wherein the paper sheet is irradiated with light obtained from a single light source, and a secondary obtained from the irradiated light. A detection step of transmitting light through a band-pass filter that selectively transmits light of a specific wavelength, and detecting the transmitted light transmitted through the first light receiving element; and a second light receiving element that is at least two light receiving elements Irradiating the light obtained from the single light source without passing through the paper sheet, receiving the light without passing through the bandpass filter, and based on the detection result of the second light receiving element, Based on the detection step for detecting the optical axis deviation of the irradiation light, the correction step for correcting the detection result in the detection step based on the detection result in the detection step, and the paper based on the correction result in the correction step Paper sheets with an identification process for identifying the optical properties of the leaves Manabu characteristic detection method.

It is explanatory drawing which shows schematic structure of the banknote discrimination apparatus 20 as 1st Example of this invention. It is the perspective view which represented typically the structure of the detection unit 30 of the banknote identification device 20. FIG. 5 is an explanatory diagram showing details of a detection unit 70. FIG. It is a flowchart which shows the flow of a shipment adjustment process. It is a flowchart which shows the flow of a detection value calibration process. It is explanatory drawing which shows the determination method of the position of the sensors 72 and 73 for calibration. It is explanatory drawing which shows the determination method of the position of the sensors 72 and 73 for calibration. It is explanatory drawing which shows the modification of the position of the sensors 72 and 73 for a calibration. It is process drawing which shows the manufacture procedure of the banknote identification device 20. It is explanatory drawing which shows schematic structure of the detection unit 400 as 2nd Example. 5 is an explanatory diagram illustrating details of a detection unit 470. FIG. It is explanatory drawing which shows the modification of the detection part. It is explanatory drawing which shows the modification of the shape of the ultraviolet cut filter 460. FIG. It is explanatory drawing which shows schematic structure of the banknote discrimination apparatus 500 as 3rd Example. It is explanatory drawing shown about the detection value calibration control in the detection value calibration process as 3rd Example. It is a flowchart which shows the procedure of the detection value calibration process as 3rd Example.

Examples of the present invention will be described.
A. First embodiment:
A-1. Configuration of the bill validator 20:
FIG. 1 is an explanatory diagram showing a schematic configuration of a banknote discriminating apparatus 20 as a first embodiment of the paper sheet optical property identifying apparatus of the present invention. The bill discriminating device 20 is a device that discriminates the authenticity of the bill Ca. For example, in a cash automatic transaction device that performs transactions such as deposit, withdrawal, and transfer of the bill Ca, an automatic vending machine that performs unattended sales of products, and the like. Installed. For example, when the bill validating device 20 is mounted on an automatic teller machine, the bill validating device 20 is provided in the middle of a bill transport path from a deposit / withdrawal port for depositing / withdrawing bills to a deposit box for storing deposited bills. . The bill Ca is generally made of paper having a characteristic that does not emit fluorescence even when irradiated with ultraviolet light, and a pattern for preventing counterfeiting using fluorescent ink (hereinafter also referred to as a fluorescent pattern) is printed. ing. The banknote discriminating apparatus 20 in the present embodiment discriminates the authenticity of the banknote Ca by irradiating the banknote Ca with ultraviolet light and detecting whether or not the above-described fluorescent pattern appears. As shown in FIG. 1, the bill validator 20 includes a detection unit 30 and a control unit 90.

  The detection unit 30 includes an irradiation unit 40, a visible cut filter 50, an ultraviolet cut filter 60, a detection unit 70, and a conveyance unit 80. The irradiation part 40 is a light source for irradiating the ultraviolet light used for discrimination of the banknote Ca. In this embodiment, a single ultraviolet light LED (Light Emitting Diode) is used. This is because the apparatus configuration can be simplified by using a single light source. However, the irradiation unit 40 may include a plurality of light sources. Further, the irradiation unit 40 may use an ultraviolet lamp or the like.

  The detection unit 70 includes a light receiving element (photosensor) that receives and detects the irradiation light IL of the irradiation unit 40. In the present embodiment, the detection unit 70 is a line-type light receiving element in which a plurality of light receiving elements are arranged without a gap along a direction orthogonal to the conveyance direction of the bill Ca by the conveyance unit 80 described later. The light receiving element is an element that outputs a voltage corresponding to the intensity of the received irradiation light. In this embodiment, a photodiode is used as the light receiving element. However, a phototransistor or the like may be used as the light receiving element. When the banknote Ca is arranged between the detection unit 70 and the irradiation unit 40, the detection unit 70 can also receive the fluorescence emitted using the irradiation light IL from the irradiation unit 40 as excitation light. In the present embodiment, the irradiation unit 40 and the detection unit 70 are provided to face each other. By doing so, even if the detection unit 30 does not include a reflecting plate or the like, the irradiation light of the irradiation unit 40 can be detected by the detection unit 70, and the apparatus can be simplified. However, the irradiation part 40 and the detection part 70 may be arrange | positioned toward the same direction side, and the structure using a reflecting plate etc. may be sufficient.

  The visible cut filter 50 is provided between the irradiation unit 40 and the detection unit 70 in the entire range of the optical path cross section orthogonal to the optical axis direction of the irradiation light IL from the irradiation unit 40 toward the detection unit 70. That is, the irradiation light IL from the irradiation unit 40 is always received by the detection unit 70 after passing through the visible cut filter 50. The visible cut filter 50 is installed in order to cut visible light from the irradiation light IL from the irradiation unit 40 and perform discrimination with higher accuracy, but is not essential.

  The ultraviolet cut filter 60 is a band-pass filter that cuts ultraviolet light, and is orthogonal to the optical axis direction of the irradiation light IL from the irradiation unit 40 toward the visible cut filter 50 between the visible cut filter 50 and the detection unit 70. A part of the cross section of the optical path, specifically, the central part of the cross section is provided. That is, the detection unit 70 transmits only the transmitted light IL1 through which the irradiation light IL passes through the visible cut filter 50 and the ultraviolet cut filter 60 and is received by the detection unit 70, and the visible cut filter 50, and detects the detection unit 70. The ultraviolet light L2 received by the light can be received. In addition, when the banknote Ca is distribute | arranged between the visible cut filter 50 and the ultraviolet cut filter 60, since the ultraviolet light which permeate | transmitted the banknote Ca is cut by the ultraviolet cut filter 60, the transmitted light IL1 is ultraviolet. Only the fluorescence excited by the bills Ca by light is included. Therefore, the transmitted light IL1 is also referred to as fluorescence IL1.

  The transport unit 80 is a transport path that transports the bill Ca to be identified on the optical path of the irradiation light IL between the visible cut filter 50 and the ultraviolet cut filter 60. In this embodiment, the transporting unit 80 uses a drive type roller conveyor. A hole is provided on the conveyance surface of the conveyance unit 80 so as not to block the optical path of the irradiation light IL.

  The control unit 90 includes an output amplifier 91 and an AD converter 92 as analog circuits. In addition, the control unit 90 executes a program recorded in a memory (not shown) by a CPU (not shown), whereby the data processing unit 93, the authenticity identification unit 94, the detection value calibration unit 95, the ultraviolet light It also functions as the control unit 96. The output amplifier 91 includes a variable gain amplifier that amplifies the output voltage from the detector 70. The AD converter 92 converts the analog output of the detection unit 70 via the output amplification unit 91 into a digital signal.

  The data processing unit 93 selects necessary data from the outputs of the AD converter 92 and outputs the selected data to the authenticity identification unit 94 and the detection value calibration unit 95. The authenticity identification unit 94 performs authenticity discrimination of the banknote Ca based on the output data from the data processing unit 93. Based on the output data from the data processing unit 93, the detection value calibration unit 95 controls the amount of light of the irradiation unit 40 by a detection value calibration process to be described later. The ultraviolet light control unit 96 controls the drive current of the irradiation unit 40 based on the control signal from the detection value calibration unit 95 to cause the irradiation unit 40 to emit light. In the present embodiment, the function configured as software may be configured as hardware using a dedicated circuit.

  FIG. 2 is a perspective view schematically showing the configuration of the detection unit 30 of the banknote discrimination device 20. Here, the description of the already described configuration is omitted. As shown in the figure, the detection unit 70 includes a discrimination light receiving area A1 (with the visible cut filter 50 and the received light IL1 transmitted through the visible cut filter 50 and the ultraviolet cut filter 60 in the irradiation light IL of the irradiation unit 40. When the bill Ca is arranged between the ultraviolet cut filter 60, only the fluorescence for authenticating the bill Ca is received, and thus called). Further, on both sides of the discrimination light receiving area A1 of the detection unit 70, an ultraviolet light receiving area A2 for receiving the ultraviolet light IL2 that has passed through only the visible cut filter 50 is formed.

  Here, a detailed configuration of the detection unit 70 will be described with reference to FIG. In this embodiment, as shown in the figure, the detector 70 has 15 light receiving elements arranged without gaps. These light receiving elements include a discrimination sensor 71 and calibration sensors 72 and 73. A discrimination sensor 71 is provided in the discrimination light reception area A1, and calibration sensors 72 and 73 are provided in the ultraviolet light reception areas A2 on both sides of the discrimination light reception area A1. The output of the discrimination sensor 71 is used for authenticating the bill Ca. The outputs of the calibration sensors 72 and 73 are used for detection value calibration processing described later. Note that the numbers of the discrimination sensor 71 and the calibration sensors 72 and 73 are not particularly limited, and each of them may be at least one.

A-2. Banknote discrimination process:
The banknote discrimination process in the banknote discrimination apparatus 20 having such a configuration will be described below. The banknote discrimination process is a process for performing authenticity discrimination of the banknote Ca. When the bill discrimination process is started, the transport unit 80 transports the bill Ca onto the optical path of the irradiation unit 40. When banknote Ca is arrange | positioned on an optical path, the control unit 90 makes the irradiation part 40 light-emit as a process of the ultraviolet-light control part 96. FIG. Visible light IL1 from the irradiation unit 40 is cut by the visible cut filter 50 and irradiated to the bill Ca. Then, using the irradiation light as excitation light, fluorescence is emitted from the bill Ca, passes through the ultraviolet cut filter 60, and is received by the discrimination sensor 71. Here, since the ultraviolet light which permeate | transmitted the banknote Ca is cut by the ultraviolet cut filter 60, it is only fluorescence IL1 that the sensor 71 for identification receives.

  When the fluorescent light IL1 is received, the discrimination sensor 71 and the calibration sensors 72 and 73 output a voltage corresponding to the intensity of the received light to the output amplifier 91. The output is digitally converted by an AD converter and output to the data processing unit 93. The data processing unit 93 selects only the output data from the discrimination sensor 71 from the input data and outputs it to the authenticity identification unit 94. The authenticity identification unit 94 performs authenticity discrimination of the bill Ca by pattern matching between the fluorescence pattern represented by the output data input from the data processing unit 93 and the fluorescence pattern of the genuine note stored in the memory.

A-3. Detection value calibration process:
The detection value calibration process in the banknote identification device 20 mentioned above is demonstrated. The detection value calibration process is a discrimination accuracy due to a change in the amount of light due to the aging deterioration of the irradiation unit 40 or the influence of the ambient temperature when using the banknote discrimination device 20 in order to perform accurate discrimination in the banknote discrimination process described above. It is a process to calibrate the influence on the. Before describing the detected value calibration process, first, a shipping adjustment process that is a premise of the detected value calibration process will be described with reference to FIG. The shipping adjustment process is a process performed in the manufacturing stage of the banknote discrimination device 20. In the present embodiment, the shipping adjustment process is performed by connecting a computer device equipped with a display to the control unit 90 of the bill validator 20 and sending a control signal from the computer device to the control unit 90 based on the manufacturer's operation. By doing so, the control unit 90 executes.

  As shown in FIG. 4, when the shipment adjustment process is started, first, the control unit 90 causes the irradiation unit 40 to emit light (step S110). Here, the intensity of the irradiation light IL irradiated by the irradiation unit 40 is a default value determined in the design stage. When the irradiation unit 40 is caused to emit light, the control unit 90 performs the processing of the data processing unit 93, the calibration sensor 72, among the data input to the data processing unit 93 via the output amplification unit 91 and the AD converter. 73, the initial outputs S072p and S073q (p and q are the respective sensors 72 and 73 for calibration, both of which are integers of 1 to 3) are read (step S120). When the initial outputs S072p and S073q are read, the control unit 90 stores the data in a nonvolatile memory included in the control unit 90 (step S130).

  When the initial outputs S072p and S073q are stored, the control unit 90 determines whether or not the stored output is a value within a specified range (step S140). As a result, if the stored output is within the specified range (step S140: YES), the control unit 90 ends the shipping adjustment process. On the other hand, if the stored data is not within the specified range (step S140: NO), it means that the output characteristics of the calibration sensors 72 and 73 are not specified, and the control unit 90 calibrates the display of the computer device. The replacement instructions for the sensors 72 and 73 are displayed (step S150), and the process is terminated. In this case, the manufacturer replaces the detection unit 70 and again executes the above-described pre-shipment adjustment process.

  Next, the detection value calibration process in the banknote discrimination device 20 will be described with reference to FIG. In this embodiment, the detection value calibration process is started when the power of the banknote discriminating apparatus 20 is turned on, and thereafter, in a period in which the authenticity discrimination process is not executed, in other words, on the optical path of the detection unit 30. It is repeatedly executed in a period in which Ca is not arranged. When the detection value calibration process is started, the control unit 90 waits for the occurrence of a predetermined event (step S210). In the present embodiment, the predetermined event is a notification that a transaction has started from the CPU of the automatic teller machine equipped with the bill validator 20. However, such an event is not particularly limited. For example, the transaction number of the automatic teller machine has reached a predetermined number, and the authenticity discrimination process in the banknote discrimination apparatus 20 is executed for a predetermined number of banknotes. Or that a predetermined period has elapsed. Moreover, if the banknote discrimination device 20 is provided with a temperature sensor, the temperature detected by the temperature sensor may exceed a predetermined range.

  And if generation | occurrence | production of a predetermined event is detected (step S210: YES), the control unit 90 will make the irradiation part 40 light-emit (step S220). When the irradiation unit 40 is caused to emit light, the control unit 90 outputs the sensor output S72p that is the output of the calibration sensors 72 and 73 among the data input to the data processing unit 93 via the output amplification unit 91 and the AD converter. , S73q is read and output to the detected value calibration unit 95 (step S230).

  Since the detection value calibration process is performed during a period in which the bill Ca is not arranged in the optical path of the detection unit 30, the sensor output data S72p and S73q are the irradiation light IL (ultraviolet light IL2) transmitted only through the visible cut filter 50. Represents the intensity of light. When the sensor outputs S72p and S73q are output, the detection value calibration unit 95 compares the initial outputs S072p and S073q stored in the nonvolatile memory by the above-described shipping adjustment process (step S240).

  The control unit 90 has all the differences Di (i is an integer from 1 to p + q) between the initial outputs S072p and S073q and the sensor outputs S72p and S73q corresponding to the initial outputs S072p and S073q (including no difference). Is determined (step S250). The difference Di here may be handled as a difference between the initial outputs S072p and S073q and the sensor outputs S72p and S73q, or may be handled as a ratio.

  As a result, if at least one of the differences Di is outside the specified range (step S250: NO), the change in the light emission performance of the irradiation unit 40 due to the influence of aging deterioration and the ambient temperature affects the authenticity discrimination. It is happening. Therefore, the control unit 90 performs detection value calibration control for calibrating the influence of the light amount change of the irradiation unit 40 (step S260), returns the process to step S230, and repeats the processes of steps S230 to S260. In short, the influence of the change in the light amount of the irradiation unit 40 is calibrated by feedback control until the difference Di is within a specified range. Note that the determination in step S250 may be configured to perform the process in step S260 when a predetermined number or all of the differences Di are out of the specified range. Alternatively, when the difference between the average value of each of the initial outputs S072p and S073q, or the overall average value of the initial outputs S072p and S073q, and the average value of the corresponding sensor outputs S72p and S73q is outside the specified range, step S260 It is good also as a structure which performs a process.

  The specific control content of step S260 in the present embodiment will be described. In step S260, the control unit 90 first changes the drive current of the irradiation unit 40. When the sensor outputs S72p and S73q read in step S230 are smaller than the initial outputs S072p and S073q, which are initial values at the time of shipment (hereinafter also referred to as degradation of the light emission performance), the drive current is increased. It will be.

  If the difference Di does not fall within the specified range even when feedback control is performed while changing the drive current, the control unit 90 increases or decreases the light emission time of the irradiation unit 40 in addition thereto. When the light emission performance is deteriorated, control for increasing the light emission time is performed. If the difference Di does not fall within the specified range even when feedback control is performed while changing the drive current and the light emission time, the control unit 90 changes the gain of the output amplifying unit 91 in addition thereto. When the light emission performance is deteriorated, control for increasing the gain is performed.

  If the difference Di does not fall within the specified range even when feedback control is performed while changing the drive current, the light emission time, and the gain, the control unit 90 performs digital amplification or digital attenuation on the input value. And control is performed so that the difference Di is within a specified range. When the light emission performance is deteriorated, digital amplification is performed. Note that the priority order of these control menus is not particularly limited, and may be changed in an arbitrary order. Further, a part of these control menus may be executed. For example, only digital amplification or attenuation may be performed, and when sufficiently large current control or gain control can be performed, only such control may be performed. When a phototransistor is used as the light receiving element of the detection unit 70, the sensitivity of the light receiving element may be changed by changing the bias current.

  On the other hand, if the differences Di are all within the specified range (step S250: YES), the change in the light emission performance of the irradiation unit 40 due to the influence of aging and ambient temperature does not occur so as to affect the authenticity discrimination, Alternatively, the light emission performance has changed, but the difference Di has been calibrated by the feedback control described above. Therefore, the control unit 90 stores the control value (current value, lighting time, gain, etc.) in which the difference Di is within the specified range in the nonvolatile memory (step S270), turns off the irradiation unit 40, and performs processing. Is restored.

  In this way, when the detection value calibration process is performed, in the banknote discrimination process executed thereafter, the control unit 90 reads the control value stored in step S270 and controls the irradiation unit 40 and the like based on the control value. Will be done. However, if the light amount calibration process is performed in advance for each banknote discrimination process, that is, if the banknote discrimination process and the light quantity calibration process are performed alternately, step S270 can be omitted. Moreover, you may enter a banknote discrimination process, with the irradiation part 40 lighted at the end of a detection value calibration process.

  The bill discriminating apparatus 20 having such a configuration is based on the result of detection by the discrimination sensor 71 of the fluorescent light IL1 obtained by transmitting the secondary light obtained by irradiating the bill Ca with the irradiation light IL from the irradiation unit 40 to the ultraviolet cut filter 60. The bill Ca is verified. Moreover, the banknote discrimination apparatus 20 detects the ultraviolet light IL2 by the calibration sensors 72 and 73 in a state where the banknote Ca is not arranged on the optical path of the irradiation light IL, and based on the result, the discrimination sensor 71 Perform calibration control of the detected value. Therefore, even if the light quantity of the irradiation part 40 fluctuates due to the influence of ambient temperature or aging deterioration, the influence can be calibrated and the authenticity of the banknote Ca can be accurately identified.

  Moreover, since the banknote discrimination apparatus 20 uses the detection part 70 provided with the line type light receiving element as the discrimination sensor 71 and the calibration sensors 72 and 73, the discrimination sensor 71 and the calibration sensors 72 and 73 are individually provided. There is no need to arrange them. Therefore, the apparatus configuration can be simplified. Further, since the ultraviolet light IL2 is detected by the calibration sensors 72 and 73 which are at least two light receiving elements, the reliability of the detection result of the ultraviolet light IL2 can be improved. As a result, the calibration control of the detection value of the discrimination sensor 71 can be performed with high accuracy.

A-4. Design method of the detection unit 30:
A design method of the detection unit 30 described above, specifically, a method of determining the size of the ultraviolet cut filter 60 and the positions of the calibration sensors 72 and 73 will be described with reference to FIGS. In FIG. 6A, the visible cut filter 50 is arranged on the optical path between the irradiation unit 40 and the detection unit 70 in the entire range in the arrangement direction of the light receiving elements constituting the detection unit 70 (not shown). The output SO1 of each light receiving element constituting the detection unit 70 when the irradiation unit 40 emits light in a state where the ultraviolet cut filter 60 and the bill Ca are not arranged is shown. Since the irradiation unit 40 is a single light source, the output SO1 is the largest around the optical axis OA of the irradiation light of the irradiation unit 40 as shown in the figure, and decreases as the distance from the optical axis increases. Here, the output value of the light receiving element near the optical axis exceeds the AD range of the AD converter 92 in this embodiment.

  On the other hand, FIG. 6B shows a visible cut filter 50 (not shown) on the optical path between the irradiation unit 40 and the detection unit 70 in the entire range in the arrangement direction of the light receiving elements constituting the detection unit 70. The output SO2 of each light receiving element which comprises the detection part 70 at the time of making the irradiation part 40 light-emit in the state by which the ultraviolet cut filter 60 and the banknote Ca are arrange | positioned is shown. That is, the output SO2 indicates the intensity distribution of fluorescence obtained from the banknote Ca. As shown in the figure, the output SO2 is the largest around the optical axis OA of the irradiation light of the irradiating unit 40, decreases as it goes away from the optical axis, and reaches a value of 0 (below the detection limit) at a predetermined location. Here, a region where the output SO2 can be detected with the optical axis OA as the center is also referred to as a fluorescence detectable region A11, and a region where SO2 cannot be detected is also referred to as a fluorescence detection limit region A12. All the outputs SO2 are within the AD range of the AD converter 92. In other words, the AD range of the AD converter 92 is determined as such.

  In the design method of the present embodiment, based on the output SO2, as shown in FIG. 7, the light receiving element in the fluorescence detectable area A11 is used as the discrimination sensor 71, and the light receiving element in the fluorescence detection limit area A12 is used as a calibration sensor. 72 and 73 are used. Specifically, on both sides of the fluorescence detectable area A11, among the light receiving elements in the fluorescence detection limit area A12, three light receiving elements 72a to 72c arranged at positions closest to the fluorescence detectable area A11 and the light receiving elements. 73a to 73c are set as calibration sensors 72 and 73, respectively. All the light receiving elements between the calibration sensors 72 and 73 are set as the discrimination sensor 71. Here, the number of light receiving elements constituting the discrimination sensor 71 is an odd number (here, nine), and the number of light receiving elements constituting the calibration sensor 72 and the number of light receiving elements constituting the calibration sensor 73 (here, three). Therefore, the calibration sensor 72 and the calibration sensor 73 are arranged symmetrically with the optical axis OA as the axis of symmetry. The reason why the calibration sensor 72 and the calibration sensor 73 are arranged symmetrically will be described later.

  Then, the size of the ultraviolet cut filter 60 is determined based on the positions of the calibration sensor 72 and the calibration sensor 73 thus determined. Specifically, all the light receiving elements of the discrimination sensor 71 can receive the secondary light transmitted through the ultraviolet cut filter 60, and the calibration sensors 72 and 73 do not pass through the ultraviolet cut filter 60. The size is set so that the irradiation light can be received. In other words, the size of the ultraviolet cut filter 60 is set within the maximum range where the fluorescence detection level is within the detectable range in all the light receiving elements of the discrimination sensor 71. In other words, the size of the ultraviolet cut filter 60 is set so that the discrimination light receiving area A1 coincides with the fluorescence detectable area A11 and the ultraviolet light receiving area A2 coincides with the fluorescence detection limit area A12.

  At this time, as shown in FIG. 7, the output SO3 at the light receiving element in the fluorescence detection limit region A12 with respect to the irradiation light of the path passing only through the visible cut filter 50 (not passing through the banknote Ca and the ultraviolet cut filter 60) is fundamental. Specifically, it is the same as the output SO1 of the corresponding area shown in FIG. However, the output SO3 in the light receiving elements 72c and 73c is smaller than the output SO1 in the light receiving elements. This is because a part of the light detected as the output SO1 is cut by the ultraviolet cut filter 60 at the output SO3.

  Further, as shown in the figure, the outputs SO2 and SO3 are all within the AD range of the AD converter. That is, if the size of the discrimination sensor 71, the calibration sensors 72 and 73, and the ultraviolet cut filter 60 is set as described above, the output of the detection unit 70 required in the above-described bill discrimination process is the output SO2, Since the output of the detection unit 70 necessary for the detection value calibration process is the output SO3, all the outputs of the detection unit 70 necessary for each process can be accommodated in the AD range. In other words, since the output of the detection value calibration process can be contained within the range of the AD range necessary for the bill discrimination process, the AD range of the AD converter 92 is unnecessarily large for the detection value calibration process. There is no need to do. This is because the outputs of the calibration sensors 72 and 73 can be kept low by determining the positions of the calibration sensors 72 and 73 in this way. If the calibration sensors 72 and 73 are set near the optical axis OA shown in FIG. 6, the AD range shown in FIG. 6 cannot properly detect the outputs of the calibration sensors 72 and 73, so that the AD range needs to be enlarged. is there. Further, such an effect can be obtained to a certain extent even if the calibration sensors 72 and 73 are merely provided at a position farther than the discrimination sensor 71 with respect to the optical axis OA.

  In the design method of the detection unit 30 described above, the number of light receiving elements of the calibration sensor 72 and the calibration sensor 73 is three, but the number is not particularly limited, and each of them may be at least one or more. That's fine. Further, the calibration sensors 72 and 73 are not necessarily arranged at a position closest to the fluorescence detection region A11, that is, a position adjacent to the discrimination sensor 71.

  For example, as shown in FIG. 8, the calibration sensor 72 and the calibration sensor 73 are connected via the invalid light receiving elements 74 and 75 that are not used for either the banknote discrimination process or the detection value calibration process, that is, with the discrimination sensor 71. The calibration sensors 72 and 73 may be provided so as not to be adjacent to each other. If the invalid light receiving elements 74 and 75 are provided between the discrimination sensor 71 and the calibration sensor 73 in this way, the visible cut filter 50 and the ultraviolet cut filter 60 can be used in a state where the bill Ca is not arranged on the optical path. Since the interference light between the transmitted light IL1 that has passed through and the ultraviolet light IL2 that passes through only the visible cut filter 50 and is received by the detection unit 70 is not received by the calibration sensors 72 and 73, the ultraviolet light IL2 Detection accuracy can be increased. Further, even if the installation position and the installation angle of the ultraviolet cut filter 60 and the irradiation unit 40 are slightly shifted due to the problem of manufacturing accuracy, the detection accuracy of the ultraviolet light IL2 can be ensured. The number of invalid light receiving elements 74 and 75 is not limited to one, and may be plural, and calibration sensors 72 and 73 may be provided at positions where fluorescence IL1 and ultraviolet light IL2 do not interfere with each other. Although not shown, the discrimination sensor 71 may also be provided with invalid light receiving elements at both ends on the calibration sensors 72 and 73 side. That is, the installation range of the discrimination sensor 71 may be smaller than the maximum range in which the fluorescence IL1 can be received. In this way, in the banknote discrimination process, the interference light between the ultraviolet light IL2 and the fluorescence IL1 is not received by the discrimination sensor 71, so that the discrimination accuracy of the banknote Ca can be improved.

  Further, such an effect can be realized even if the invalid light receiving elements 74 and 75 are not provided. For example, as shown in FIG. 7, in the banknote discriminating apparatus 20 including the detection unit 70 in which the discrimination sensor 71 and the calibration sensors 72 and 73 are adjacent to each other, the control unit 90 includes the light receiving elements 72 a to 73 c. The relatively large output value (in FIG. 7, the output value of the light receiving element 72b) and the relatively large output value of the output values of the light receiving elements 73a to 73c (in FIG. 7, the light receiving element 73b). The above-described detection value calibration processing may be performed using the By doing so, the output SO3 in the light receiving elements 72c and 73c adjacent to the discrimination sensor 71 becomes smaller than the output SO1 due to the influence of the ultraviolet cut filter 60 as described above. This is because the output value of the light receiving element at a position where influence is avoided can be used for the detection value calibration process. Note that the number of relatively large output values is not limited to one, and may be plural. This is because if the number of output values to be used increases, the reliability of the output values increases and the detection accuracy of the ultraviolet light L2 can be improved.

A-5. Manufacturing method of banknote discrimination device 20:
The manufacturing procedure of the banknote discrimination apparatus 20 mentioned above is demonstrated using FIG. In manufacture of the banknote identification device 20, first, each of the structural member of the banknote identification device 20 mentioned above is prepared (step S310). Next, the bill validator 20 is assembled based on the prepared components (step S320).

  When the bill validator 20 is assembled, the control unit 90 causes the irradiation unit 40 to emit light (step S330) and read the initial outputs S072p and S073q in a state where the bill Ca is not disposed on the optical path of the irradiation unit 40 (step S340). ). In this embodiment, a computer is connected to the bill validator 20 and a control signal is sent from the computer to the bill validator 20 to execute steps S330 and S340, and initial output data S072p and S073q are stored in the computer. I decided to make it output. However, steps S330 and S340 and step S350 described later may be realized in the control unit 90 by a program provided in the control unit 90 of the bill validating device 20.

When the initial outputs S072p and S073q are obtained, the optical axis deviation coefficient F is calculated based on the initial outputs (step S350). The optical axis deviation coefficient F is an index for evaluating the degree of optical axis deviation of the irradiation unit 40, and is obtained by the following equation (1) in this embodiment. AV72 and AV73 represent average values of the initial outputs S072p and S073q, respectively.
F = AV72 / (AV72 + AV73) (1)

  In the present embodiment, the calibration sensor 72 and the calibration sensor 73 are arranged symmetrically with the optical axis OA of the irradiation unit 40 as the symmetry axis, and therefore there is no optical axis deviation in the irradiation unit 40. In this case, the optical axis deviation coefficient F = 0.5. Further, when the optical axis OA is deviated toward the calibration sensor 72, the optical axis deviation coefficient F> 0.5, and the optical axis deviation increases as the optical axis deviation coefficient F increases. Is shown. Similarly, when the optical axis OA is shifted to the calibration sensor 73 side, the optical axis deviation coefficient F <0.5, and the optical axis deviation increases as the optical axis deviation coefficient F decreases. It is shown that. Thus, the optical axis deviation coefficient F can be an index representing the direction and degree of the optical axis deviation of the optical axis OA.

  In the above example, the optical axis deviation coefficient F is calculated using the average values of the initial outputs S072p and S073q, but instead of the average value, for example, output values of p = 2 and q = 2. May be used. The average value is used in order to improve the detection accuracy of the optical axis deviation. The optical axis deviation coefficient F may be F = AV73 / (AV72 + AV73), F = AV72 / AV73, or the like. The optical axis deviation coefficient F only needs to represent the ratio between the output of the calibration sensor 72 and the output of the calibration sensor 73.

  When the optical axis deviation coefficient F is calculated, it is determined whether or not the calculated optical axis deviation coefficient F is within a specified range (step S360). The specified range is F = 0.5 in the present embodiment, but may be set as appropriate, for example, 0.45 ≦ F ≦ 0.55 in consideration of allowable measurement accuracy. .

  As a result, if the optical axis deviation coefficient F is within the specified range (step S360: YES), the optical axis deviation of the irradiating unit 40 is within the allowable range, and the banknote discrimination device 20 is completed. On the other hand, if the optical axis deviation coefficient F is outside the specified range (step S360: NO), the optical axis deviation of the irradiating unit 40 is outside the allowable range, so the optical axis deviation elimination work is performed (step S370). Specifically, the irradiation unit 40 and the detection unit 70 are reassembled to adjust the installation position and the installation angle. Then, the steps S330 to S370 are repeated until the optical axis deviation coefficient F falls within the specified range.

  The manufacturing method of the banknote discrimination device 20 uses the output of the calibration sensors 72 and 73 obtained by causing the irradiation unit 40 to emit light in a state where the banknote Ca is not disposed on the optical path of the irradiation unit 40. Since the axial deviation can be grasped, the optical axis deviation of the irradiation unit 40 can be adjusted, and the detection value calibration process and the banknote discrimination process can be performed with high accuracy. The banknote discrimination device 20 can be manufactured by such a method because the banknote discrimination device 20 includes calibration sensors 72 and 73 that are at least two light receiving elements. In particular, in this embodiment, the calibration sensor 72 and the calibration sensor 73 are arranged symmetrically with the optical axis OA as the symmetry axis, so the degree and direction of the optical axis deviation can be grasped by the optical axis deviation coefficient F. Cheap.

B. Second embodiment:
A bill validating device as a second embodiment of the present invention will be described. The bill discriminating apparatus as the second embodiment is different from the first embodiment in the configuration of the detection unit. Hereinafter, differences from the first embodiment will be described. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted. The configuration of the detection unit 400 as the second embodiment is shown in FIG. As illustrated, the detection unit 400 includes an irradiation unit 440, a visible cut filter 50, an ultraviolet cut filter 460, a detection unit 470, and a transport unit 80. The arrangement order in the optical axis direction is the same as that in the first embodiment.

  The irradiation unit 440 is different from the first embodiment in that the irradiation unit 440 is a line light source configured by arranging a plurality of ultraviolet LEDs in the arrangement direction of the light receiving elements of the detection unit 70. Thus, by providing a line light source, compared with the case where a single light source is used like 1st Example, since an irradiation range spreads, a wider range banknote Ca can be identified at once. Further, the ultraviolet cut filter 460 is different from the first embodiment in that it includes a plurality of slits 462. Note that the number of slits 462 may be at least one. The detection unit 470 is a line type light receiving element as in the first embodiment. However, the arrangement of the discrimination sensor 471 and the calibration sensors 472 and 473 is different from that of the first embodiment. Details of this point will be described later.

  Moreover, the structure which looked at the ultraviolet cut filter 460 from the visible cut filter 50 side is shown in FIG.10 (b). As shown in the figure, in the ultraviolet cut filter 460 of the present embodiment, the slits 462 are formed as through holes provided at equal intervals in the arrangement direction of the light receiving elements of the detection unit 470. In addition, each slit 462 is formed with a width wider than that of the detection unit 470 in a direction orthogonal to the arrangement direction of the light receiving elements.

  The configuration of the detection unit 470 is shown in FIG. As shown in the drawing, the detection light receiving area A1 and the ultraviolet light receiving area A2 are formed in the detection unit 470 by the ultraviolet cut filter 460 and the slit 462 provided in the ultraviolet cut filter 460. Specifically, since the ultraviolet cut filter 460 includes the slit 462, the ultraviolet light receiving area A2 is also formed at a position corresponding to the slit 462. As a result, the discrimination light receiving area A1 and the ultraviolet light receiving area A2 are alternately formed in the arrangement direction of the light receiving elements. The discrimination light receiving area A1 thus formed is provided with a discrimination sensor 471, and the ultraviolet light receiving area A2 is provided with calibration sensors 472 and 473. As a result, it is possible to reduce the interval between the calibration sensors 472 and 473 as compared with the case where there is no slit 462.

  In the detection value calibration process in the bill discriminating apparatus 20 having such a configuration, only the output of the calibration sensors 472 and 473 adjacent to each discrimination sensor 471 is used, and the light source disposed near the discrimination sensor 471 is used. Alternatively, detection value calibration control (step S260) is performed on the output data of the discrimination sensor 471. In this way, even if light source unevenness occurs in the arrangement direction of the light receiving elements of the irradiation unit 440 due to a change in the light amount of each light source constituting the line light source, the position of the light receiving element of the discrimination sensor 471 of the detection unit 470 Since the detection value calibration process can be performed by performing calibration according to the above, the accuracy of the detection value calibration process can be improved.

  However, as in the first embodiment, the average output of each of the calibration sensors 472 and 473 is used to uniformly apply to all line light sources or output data of all the discrimination sensors 471. The detected value calibration control may be performed. Even in this case, since the detection value calibration control can be performed based on the calibration sensors 72 and 73 having a small arrangement interval, the calibration sensors 72 and 73 are arranged only at both ends of the detection unit 70 as in the first embodiment. Compared with the above, the influence of light source unevenness can be reduced.

  In addition, as shown in FIG. 12, the detection unit 470 is formed with an interference area A3 where the fluorescence IL1 and the ultraviolet light IL2 interfere. Therefore, similarly to the first embodiment, the control unit 90 may perform the detection value calibration control using the outputs of the calibration sensors 472 and 473 that are set to avoid the interference area A3. By so doing, the detection accuracy of the ultraviolet light IL2 by the calibration sensors 472 and 473 can be increased as in the first embodiment.

  A modification of the shape of the detection unit 470 is shown in FIG. FIG. 13 shows the shapes of the two ultraviolet cut filters 460a and 460b and the installation positions of the detectors 470 corresponding thereto. The ultraviolet cut filters 460a and 460b are obtained by cutting one substantially rectangular filter into two. In the ultraviolet cut filter 460a, slits 462a in which one piece is notched and convex portions 464a that are non-notched portions between adjacent slits 462a are alternately and repeatedly formed. The slits 462a and the convex portions 464a have the same size.

  The ultraviolet cut filter 460b is a remaining portion obtained by cutting the slit 462a from one substantially rectangular filter. Due to the shape of the ultraviolet cut filter 460a described above, the shape of the ultraviolet cut filter 460b is a shape in which the ultraviolet cut filter 460a is slid by the width in the repeating direction of the slit 462a. In the ultraviolet cut filters 460a and 460b, the slits 462a and 462b are formed with a width wider than that of the detection unit 470 in the direction orthogonal to the arrangement direction of the light receiving elements of the detection unit 470.

  If the slits 462a and 462b having such shapes are arranged at the center of the slits 462a and 462b in the direction perpendicular to the arrangement direction of the light receiving elements of the detection unit 470, as shown in FIG. The same function as the ultraviolet cut filter 460 can be exhibited. Further, the slits 462a and 462b having such shapes can be manufactured by cutting a substantially rectangular filter without waste, which contributes to resource saving and cost reduction.

C. Third embodiment:
A banknote discrimination apparatus 500 as a third embodiment will be described. The bill discriminating apparatus 500 as the third embodiment is different from the first embodiment in the configuration of the control unit. In the following description, only differences from the first embodiment will be described, and description of points common to the first embodiment will be omitted. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment. The structure of the banknote identification device 500 as a 3rd Example is shown in FIG. The control unit 590 of the bill validator 500 also functions as an optical axis deviation detector 597. The optical axis deviation detection unit 597 detects the optical axis deviation of the irradiation unit 40 from the outputs of the calibration sensors 72 and 73 and outputs the detected optical axis deviation to the detection value calibration unit 95. In response to this, the detection value calibration unit 95 corrects the output of the discrimination sensor 71 based on the detected degree of optical axis deviation, and performs detection value calibration control using the correction result. The control unit 590 stores a correction coefficient table Ta in a non-volatile memory described later (not shown).

  The detection of optical axis deviation and detection value calibration control in the present embodiment will be specifically described below. First, the premise of the third embodiment will be described. In order to simplify the description, as shown in FIG. 15A, the detection unit 70 according to the third embodiment includes a discrimination sensor 71 including five light receiving elements and a calibration sensor including one light receiving element. 72, 73. The output of each light receiving element of the discrimination sensor 71 in the banknote discrimination process via the AD converter 92 is the output of the light receiving element closest to the calibration sensor 72 as an output X1, and toward the calibration sensor 73 side, The outputs of the respective light receiving elements are called outputs X2, X3, X4, and X5. The outputs of the calibration sensors 72 and 73 in the detection value calibration process are referred to as outputs XL and XR, respectively.

  FIG. 16 shows the flow of detection value calibration processing as the third embodiment. In FIG. 16, the same steps as those in the detection value calibration process as the first embodiment shown in FIG. 5 are denoted by the same reference numerals as those in FIG. 5, and the description is simplified. When the detection value calibration process as the third embodiment is started, the control unit 590 waits for the occurrence of a predetermined event (step S210), and when the occurrence of the event is detected (step S210: YES), the irradiation unit 40. Is caused to emit light (S220). When the irradiation unit 40 is caused to emit light, the control unit 590 reads the outputs XL and XR which are the outputs of the calibration sensors 72 and 73 input to the data processing unit 93 via the output amplification unit 91 and the AD converter (Step) S230).

  When the outputs XL and XR are read, the control unit 590 reads the initial outputs XL0 and XR0 of the calibration sensors 72 and 73 stored in the nonvolatile memory by the shipping adjustment process (step S610). When the initial outputs XL0 and XR0 are read, the control unit 590 detects the optical axis deviation of the irradiation unit 40 as a process of the optical axis deviation detection unit 597 (step S620). Specifically, the optical axis deviation coefficient F (= XL0 / (XL0 + XR0)) is calculated using the initial outputs XL0 and XR0 read in step S610.

  When the optical axis deviation is detected, the control unit 590 receives the optical axis deviation coefficient F from the optical axis deviation detection unit 597 as detection value calibration unit 95 processing, and performs detection value calibration control (step S630). The detection value calibration control performed in step S630 is digital amplification or digital attenuation.

  The process of step S630 will be described in more detail. In general, it is known that the light absorption that causes the excitation of the substance changes in proportion to the square of the incident light, and the fluorescence excited from the bill Ca has a weak light output from the irradiation unit 40. The output distribution becomes smaller. Accordingly, when the optical axis of the irradiation light is deviated, the output distribution of fluorescence excited by the irradiation light of the irradiating unit is also deviated according to the deviation. Based on this phenomenon, in step S630, digital amplification or digital attenuation is performed on the outputs X1 to X5 obtained from the discrimination sensor 71 so that calibration can be performed including the influence of the optical axis deviation. Hereinafter, such processing will be described.

  The control unit 590 stores a correction coefficient table Ta. A specific example of the correction coefficient table Ta is conceptually shown in FIG. In the correction coefficient table Ta, the optical axis deviation coefficient F and the correction coefficient CF1 are associated with each other. The correction coefficient CF1 represents the light quantity at the position where the light of the irradiation light IL is the strongest, that is, the position corresponding to the optical axis, by the reference coefficient a. In addition, with reference coefficient a as a reference, the reciprocal of the degree that the light at the position is weakened every time the light receiving element is moved away from the position is represented by coefficients b, c, d, and e. By multiplying each output of the discrimination sensor 71 by the correction coefficient CF1, the light intensity at each position of the discrimination sensor 71 can be made to be equal in a pseudo manner. For example, when the reference coefficient a = 1, if the amount of light at a position separated by one light receiving element from the optical axis is 0.7 times the position corresponding to the optical axis, the coefficient b = 1 / 0.7, If the light quantity at a position separated by two light receiving elements from the optical axis is 0.5 times the optical axis corresponding position, the coefficient c = 1 / 0.5. These coefficients are obtained experimentally in optical design. Since the light intensity attenuates in inverse proportion to the square of the distance from the light source, the correction coefficient CF1 can be obtained simply by calculation based on the positional relationship between the irradiation unit 40 and the detection unit 70. Since the optical characteristics are complicated due to the difference in the characteristics of the light output distribution depending on the lens shape of the irradiation unit 40 and the diffusion of the ultraviolet light inside the bill Ca, it is experimental at the optical design stage. It is desirable to ask for.

  In the correction coefficient CF1, the position of the light receiving element associated with the reference coefficient a changes depending on the degree of optical axis deviation. In the example of FIG. 15B, when there is no optical axis deviation, that is, when the optical axis deviation coefficient F = 0.5, the reference coefficient a corresponds to the light receiving element at the center of the discrimination sensor 71. , The output X3 and the reference coefficient a are associated with each other, and the outputs X2 and X4 at positions separated by one light receiving element are associated with the coefficient b and the outputs X1 and X5 at positions separated by two light receiving elements. Is associated with a coefficient c. Further, when the optical axis deviation coefficient F = 0.6, the change amount of the position where the light of the irradiation light IL becomes the strongest is not enough for one light receiving element, and the correction coefficient CF1 is the optical axis deviation coefficient F. = The same as in the case of 0.5.

  On the other hand, when the optical axis deviation coefficient F = 0.7, the change amount of the position where the light of the irradiation light IL is the strongest corresponds to one light receiving element, and the reference coefficient a is the value of the discrimination sensor 71. Corresponding to the output X2 at a position shifted by one light receiving element in the direction of the discrimination sensor 71 from the center, the output X1, X3 has a coefficient b, the output X4 has a coefficient c, and the output X5 has a coefficient d. Are associated. When the optical axis deviation coefficient F = 0.8, the correction coefficient CF1 is the same as that when the optical axis deviation coefficient F = 0.7 for the same reason as in the case of the optical axis deviation coefficient F = 0.6. It has become.

  Similarly, when the optical axis deviation coefficient F = 0.9, the amount of change in the position where the light of the irradiation light IL is the strongest corresponds to two light receiving elements, and the reference coefficient a is the identification sensor. It is associated with the output X1 at a position shifted by two light receiving elements in the direction of the discrimination sensor 71 from the center of 71, the coefficient b for the output X2, the coefficient c for the output X3, and the coefficient d for the output X4. However, the coefficient e is associated with the output X5. Although not shown in FIG. 15B, the correction coefficient table Ta also includes outputs X1 to X5 in the same manner as the illustrated part even when the optical axis deviation coefficient F is less than 0.5. Is associated with the correction coefficient CF1.

  The control unit 90 refers to the correction coefficient table Ta, reads the correction coefficient CF1 corresponding to the optical axis deviation coefficient F calculated in step S620, and outputs these coefficients, outputs XL and XR, and initial outputs XL0 and XR0. Is used to perform digital amplification or digital attenuation of the outputs X1 to X5. A specific example is shown in FIG. This example shows the contents of digital amplification or digital attenuation when the optical axis deviation coefficient F = 0.7. Since the correction coefficient CF1 (X1, X2, X3, X4, X5) corresponding to the optical axis deviation coefficient F = 0.7 = (b, a, b, c, d), the output X11 after the correction of the output X1 Is X11 = X1 × (XL0 / XL) × b. “XL0 / XL” corrects the amount of change in the output XL with respect to the initial output XL0, that is, the amount of change in the amount of light from the factory shipment, and “b” corrects the influence of the optical axis deviation. is there.

  Further, for example, the output X14 after the correction of the output X4 is X14 = X4 × (XR0 / XR) × c. In the present embodiment, in this way, the output X1 corrects the light quantity change using “XL0 / XL”, and the output X4 corrects the light quantity change using “XR0 / XR”. That is, “XL0 / XL” that is the output of the calibration sensor 72 is used for the light receiving element on the calibration sensor 72 side, and “XR0” that is the output of the calibration sensor 73 is used for the light receiving element on the calibration sensor 73 side. / XR "is used. This is because the calibration accuracy is enhanced by using the output of the calibration sensors 72 and 73 on the side closer to the light receiving element to be corrected. In this embodiment, “XR0 / XR” is used for the output X3 of the light receiving element located at the center of the discrimination sensor 71 for convenience. However, the average value of “XL0 / XL” and “XR0 / XR” may be used for the output X3. Of course, an average value may be used for all of the outputs X1 to X5. In this way, when the detection value calibration control is performed, the detection value calibration process ends.

  The bill discriminating apparatus 500 having such a configuration can obtain the output of the discrimination sensor 71 calibrated with respect to the optical axis deviation of the irradiation unit 40 in addition to the light amount change of the irradiation unit 40, and can perform the bill discrimination processing with high accuracy. . In other words, the optical axis shift of the irradiation unit 40 can be allowed in the manufacturing stage of the banknote identification device 500. Therefore, the restrictions at the time of manufacture of the bill validator 500 can be reduced, the manufacturing process can be simplified, and the cost of the bill validator 500 can be reduced. Such a configuration can be realized by including calibration sensors 72 and 73 including two or more light receiving elements.

  In the above-described example, the calibration sensors 72 and 73 have been described as including a single light receiving element. However, even if each of the calibration sensors 72 and 73 includes a plurality of light receiving elements, You may use the average value of the output of a light receiving element, or may use the largest output.

  Further, the detection value calibration process of FIG. 16 can be applied even after the bill discriminating apparatus 500 is shipped, that is, in use, even when the optical axis shift of the irradiation unit 40 has occurred for some reason. That is, the optical axis deviation coefficient F calculated in step S620 is calculated as “XL / (XL + XR)” instead of “XL0 / (XL0 + XR0)”, and based on this, detection value calibration control in step S630 is performed. May be. If it carries out like this, even if the banknote discrimination apparatus 500 receives an impact etc. and produces optical axis deviation at the time of use, the precision of a banknote discrimination process can be kept high.

D. Variation:
A modification of the above-described embodiment will be described.
D-1. Modification 1:
In the above-described embodiment, the configuration in which the calibration sensors 72 and 73 are arranged on both sides of the discrimination sensor 71 has been described. However, the arrangement is not necessarily limited to such an arrangement. For example, in the first and third embodiments, the calibration sensors 72 and 73 do not have to be arranged symmetrically with the optical axis as the symmetry axis, or are arranged at the center or one side of the discrimination sensor 71. You may arrange. When the light receiving elements of the detection unit 70 are also arranged in the banknote Ca conveyance direction, the calibration sensors 72 and 73 may be arranged on both sides of the direction. Even in such a case, it is possible to improve the reliability of the detection value calibration processing by using the outputs of the calibration sensors 72 and 73 that are two or more light receiving elements.

  Further, when the calibration sensors 72 and 73 are not symmetrical, the determination of the optical axis deviation may be made based on the value of the optical axis deviation coefficient F corresponding to the arrangement angle. For example, when the calibration sensors 72 and 73 are arranged so that the distance between the calibration sensor 72 and the optical axis OA is shorter than the distance between the calibration sensor 73 and the optical axis OA, the optical axis deviation coefficient When F = XL0 / (XL0 + XR0) = 0.7, it may be determined that there is no optical axis deviation. However, it is clear that the calibration sensors 72 and 73 can be improved in the accuracy of detecting the optical axis deviation if they are arranged apart from each other. In addition, the symmetrical arrangement makes it easier to grasp the degree and direction of the optical axis deviation.

D-2. Modification 2:
In the above-described embodiment, the optical path of the fluorescent light IL1 and the ultraviolet light IL2 is not particularly provided with a partition, but both optical paths may be blocked using a light shielding plate or the like. In this way, the detection value calibration process can be performed with high accuracy while avoiding interference between the fluorescent light IL1 and the ultraviolet light IL2.

D-3. Modification 3:
In the above-described embodiment, the ultraviolet cut filter 60 and the detection unit 70 are configured separately, but may be configured integrally. For example, the ultraviolet cut filter 60 may be formed on the surface of the discrimination sensor 71 of the detection unit 70 or the lens corresponding thereto by vapor deposition or coating. In this way, the apparatus can be made compact and interference between the fluorescent light IL1 and the ultraviolet light IL2 can be suppressed.

D-4. Modification 4:
In the above-described embodiment, the outputs of the calibration sensors 72 and 73 are used only for the detection value calibration process, but may be used for the banknote discrimination process. That is, the fluorescent state of the banknote Ca may be detected by the discrimination sensor 71, and the ultraviolet light transmission state of the banknote Ca may be detected by the calibration sensors 72 and 73. If it carries out like this, since banknote discrimination can be performed by two types of methods simultaneously, discrimination accuracy can be raised. Or it is not necessary to provide two types of devices individually. The device configuration can be simplified.

D-5. Modification 5:
In the third embodiment, the optical axis deviation is detected from the outputs of the calibration sensors 72 and 73, and the detection value calibration control is shown based on the detection result with reference to the correction coefficient table Ta. The aspect can also be applied for calibration of local fogging of the lens of the irradiation unit 40. This is because when the lens is locally clouded, a difference occurs in the outputs of the calibration sensors 72 and 73 according to the position and degree of the cloudiness. In this case, a correction coefficient corresponding to the ratio of the outputs of the calibration sensors 72 and 73 corresponding to the assumed fogging may be obtained experimentally and stored as a table. Further, when a line light source is used for the irradiation unit 40 as in the second embodiment, a difference occurs in the outputs of the calibration sensors 72 and 73 depending on the degree of change in the brightness of the adjacent light source. It can also be applied as a calibration configuration. In this case, a correction coefficient corresponding to the ratio of the outputs of the calibration sensors 72 and 73 corresponding to the assumed brightness change may be experimentally obtained and stored as a table.

D-6. Modification 6:
In the above-described embodiment, ultraviolet light is used as the excitation light of the banknote Ca. However, the excitation light is not limited to ultraviolet light, and may be infrared light, for example. In this case, a corresponding bandpass filter may be used instead of the ultraviolet cut filter 60. Further, the number of band pass filters is not limited to one, and a plurality of types may be used.

D-7. Modification 7:
In the above-mentioned embodiment, although it showed about the structure which discriminate | determines banknote Ca based on the fluorescence obtained from banknote Ca, the discrimination light of banknote Ca is not restricted to fluorescence but phosphorescence etc. may be sufficient. Moreover, you may distinguish by both fluorescence and phosphorescence. That is, what is necessary is just to identify the optical characteristics of the secondary light obtained by irradiating the bill Ca with light and using the irradiated light as excitation light.

  The embodiment of the present invention has been described above, but among the components of the present invention in the above-described embodiment, elements other than the elements described in the independent claims are additional elements and can be omitted as appropriate. Moreover, although the embodiment of the present invention has been described, the present invention is not limited to such an example, and it is needless to say that the present invention can be implemented in various modes without departing from the gist of the present invention. For example, the present invention can be widely applied not only to a bill authenticity discrimination apparatus but also to various optical sheet identification devices for handling paper sheets such as banknotes, securities, and forms.

DESCRIPTION OF SYMBOLS 20 ... Banknote discrimination apparatus 30 ... Detection unit 40 ... Irradiation part 50 ... Visible cut filter 60 ... Ultraviolet cut filter 70 ... Detection part 71 ... Identification sensor 72, 73 ... Calibration sensor 72a-72c, 73a-73c ... Light receiving element 74 ... invalid light receiving element 80 ... transport unit 90 ... control unit 91 ... output amplification unit 92 ... AD converter 93 ... data processing unit 94 ... authenticity identification unit 95 ... detection value calibration unit 96 ... ultraviolet light control unit 400 ... detection unit 440 ... Irradiation part 460, 460a, 460b ... Ultraviolet cut filter 462, 462a, 462b ... Slit 464a, 464b ... Convex part 470 ... Detection part 471 ... Identification sensor 472, 473 ... Calibration sensor 500 ... Banknote discrimination apparatus 590 ... Control unit 597 ... Optical axis deviation detector S072p, S073q ... Initial output S72p, 73q ... sensor output SO1-SO3 ... output A1 ... differential light receiving area A2 ... ultraviolet light receiving area A3 ... interference area A11 ... fluorescence detectable area A12 ... fluorescence detection limit area X1 to X5, XL, XR ... output IL ... irradiation light IL1 ... fluorescence, transmitted light IL2 ... ultraviolet light Ca ... banknote OA ... optical axis Ta ... correction coefficient table CF1 ... correction coefficient

Claims (15)

A paper sheet optical characteristic identification device for detecting optical characteristics of a paper sheet,
An irradiating unit for irradiating light;
A bandpass filter that is provided in a part of the optical path of the irradiation light irradiated by the irradiation unit and selectively transmits light of a specific wavelength;
A detection unit in which a plurality of light receiving elements for detecting light are arranged, the first light receiving element including at least one light receiving element that receives light transmitted through the band pass filter, and not transmitted through the band pass filter A detection unit including a second light receiving element composed of at least two light receiving elements that receive at least light of the path;
Secondary light obtained from the paper sheets disposed on the optical path of the irradiated light as excitation light using the irradiated light irradiated on the paper sheets, and transmitted through the bandpass filter. An identification unit for identifying optical characteristics of the paper sheet based on a detection result of the first light receiving element;
A controller that calibrates the detection result of the first light receiving element based on the detection result of the second light receiving element in a state where the paper sheet is not disposed on the optical path of the irradiation light; Paper sheet optical property identification device provided.   The controller performs at least one of the control of the light emission amount of the irradiation unit, the correction of the detection result of the first light receiving element, and the adjustment of the sensitivity of the first light receiving element as the calibration. The paper sheet optical characteristic identification device according to claim 1.   The paper sheet optical property identification device according to claim 1, wherein the irradiation unit and the detection unit are disposed to face each other with the band-pass filter interposed therebetween.   The paper sheet optical characteristic identification device according to any one of claims 1 to 3, wherein the irradiation unit is a single light source.   The paper sheet optical characteristic identification device according to claim 4, wherein at least two light receiving elements constituting the second light receiving element include two light receiving elements arranged apart from each other.   6. The paper sheet optical characteristic identification device according to claim 5, wherein at least two light receiving elements constituting the second light receiving element are arranged symmetrically with respect to an optical axis of the irradiation light.   The paper sheet optical characteristic identification device according to claim 4, wherein the second light receiving element is provided at a position farther than the first light receiving element with respect to an optical axis of the irradiation light. .   Further, an optical axis deviation detection for detecting an optical axis deviation of the irradiation light based on a detection result of the second light receiving element in a state where the paper sheet is not disposed on the optical path of the irradiation light. The paper sheet optical property identification device according to any one of claims 4 to 7, further comprising a section.   The paper sheet optical characteristic identification device according to claim 8, wherein the control unit corrects at least the detection result of the first light receiving element as the calibration based on a detection result of the optical axis deviation detection unit. . The paper sheet optical property identification device according to any one of claims 1 to 3,
The irradiation unit is a line light source in which a plurality of light sources are arranged in the arrangement direction of the light receiving elements,
The paper sheet optical characteristic identification device, wherein the band-pass filter includes at least one slit in an arrangement direction of the light receiving elements.   The said control part performs the said calibration based on the output result in the light receiving element which is not adjacent to the said 1st light receiving element among the said 2nd light receiving elements. Paper optical characteristics identification device.   The paper sheet according to claim 1, wherein the controller performs the calibration based on an output result of a light receiving element having a relatively large output value among the second light receiving elements. Optical characteristics identification device.   The control unit is based on an output result of a light receiving element provided at a position where light transmitted through the band pass filter and light not transmitted through the band pass filter of the second light receiving elements do not interfere with each other. The paper sheet optical characteristic identification device according to claim 1, wherein the calibration is performed. A method for designing a paper sheet optical property identification device according to any one of claims 1 to 13,
When it is assumed that the second light receiving element has received the secondary light transmitted through the bandpass filter, the detection level of the secondary light at the second light receiving element is less than the detectable range. A design method for a paper sheet optical property identifying apparatus in which the second light receiving element is disposed. A paper optical property detection method for detecting optical properties of paper,
Irradiates light from a single light source onto a paper sheet, transmits secondary light obtained from the irradiated light through a bandpass filter that selectively transmits light of a specific wavelength, and transmits the transmitted light. Detecting the first light receiving element,
The second light receiving element, which is at least two light receiving elements, is irradiated with light obtained from the single light source without passing through the paper sheet, and is received without passing through the band pass filter. A detection step of detecting an optical axis shift of the irradiation light based on a detection result of the light receiving element;
Based on the detection result in the detection step, a correction step for correcting the detection result in the detection step,
A paper sheet optical property detection method comprising: an identification step of identifying an optical property of the paper sheet based on a correction result in the correction step.

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