JPH09231436A - Paper sheet counterfeit discriminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely discriminate the counterfeit for even paper sheets deteriorated in a reflecting characteristic or absorbing characteristc because of soil, etc., by allowing a counterfeit discriminating means to discriminate the counterfeit for paper sheets to be checked through the use of correction data. SOLUTION: A first wavelength selective filter 15 allows only light in a specific wavelength band among light reflected by the paper sheets to be checked A to pass and a first detection means (photosensor) 17 detects the light quantity of light passing the first filter 15. A second wavelength selective filter 16 allows only light in another wavelength band among light reflected by the paper sheets to be checked A to pass and a second detection means (photosensor) 18 detects the light quantity of light passing the second filter 16. An arithmetic means (differential amplifier) 23 subtracts light quantity data detected by the detection means 18 from light quantity data detected by the detection means 17 to find correction data. The counterfeit discriminating means B discriminates the counterfeit for the paper sheets to be checked A through the use of correction data obtained by the arithmetic means 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for discriminating the authenticity of paper sheets such as banknotes, stamps and securities.

[0002]

2. Description of the Related Art Conventionally, paper sheets such as banknotes, stamps and securities have been subjected to special processing for detecting counterfeit products. That is, a paper sheet is printed using a special ink that reflects or absorbs light of a special wavelength other than visible light, or a special ink that reflects or absorbs light of a special wavelength other than visible light. I also make paper sheets using dyes.

As a device for identifying the authenticity of a paper sheet that has been subjected to such a special process, a light irradiation unit that irradiates the paper sheet with only ultraviolet rays or infrared rays, and the amount of light reflected by this irradiation. 2. Description of the Related Art Conventionally, there is a paper sheet authenticity discriminating apparatus provided with a genuineness / counterfeit judging section for detecting the true / false of a paper sheet.

[0004]

However, in the conventional paper sheet authenticity discriminating apparatus, when the paper sheet is dirty, the light emitted from the light irradiation section is sufficiently reflected on the surface of the paper sheet or Since it is not absorbed, it is difficult for the authenticity determination unit to accurately determine the authenticity of the paper sheet. Further, when the reflection sensitivity or the absorption sensitivity to the light of a special wavelength other than the visible light of the paper sheet is poor, the light amount of the reflected light that can be detected by the authenticity determination unit is slightly different between the genuine product and the counterfeit product. Therefore, it is difficult for the authenticity determination unit to accurately determine the authenticity of the paper sheet.

The present invention solves such a problem and provides a paper sheet authenticity discriminating apparatus capable of highly accurately determining the authenticity of a paper sheet having poor reflection characteristics or absorption characteristics due to dirt or the like. The purpose is to

[0006]

In order to solve the above problems, the paper sheet authenticity discriminating apparatus of the present invention uses a special ink whose light reflectance in a specific wavelength band is different from that in other wavelength bands. In a device for identifying the authenticity of a printed paper sheet to be inspected, an irradiation means for irradiating the paper sheet to be inspected with light having a wavelength component of a specific wavelength band and a wavelength component of another wavelength band, and an inspection object. Light branching means for branching the light reflected by the paper sheet in two directions, and one of the lights branched by the light branching means, and a first wavelength selection for allowing only light in a specific wavelength band of the incident light to pass therethrough. Optical filter, a second wavelength selective filter that allows the other light branched by the optical branching unit to enter, and passes only light in other wavelength bands of this incident light, and a first wavelength selective filter. Of the incident light to detect the amount of the incident light. , Incident light passing through the second wavelength selective filter, the detecting the light quantity of the incident light 2
Based on the correction data obtained by the calculation means, the calculation means for subtracting the light quantity data detected by the second detection means from the light quantity data detected by the first detection means to obtain correction data, An authenticity identifying unit for identifying the authenticity of the inspection paper sheet is provided.

According to the paper sheet authenticity discriminating apparatus of the present invention having such a configuration, the light emitted from the irradiation means is reflected on the surface of the paper sheet to be inspected and enters the light branching means. The light that has entered the light branching unit is branched in two directions, and one of the branched lights passes through the first wavelength selective filter and becomes light in a specific wavelength band. Then, the light in the specific wavelength band is incident on the first detecting means, and the light amount of the light in the specific wavelength band is detected by the first detecting means.

The other light split by the light splitting means is
It passes through the second wavelength selective filter and becomes light in another wavelength band. Then, the light of the other wavelength band is incident on the second detecting means, and the light amount of the light of the other wavelength band is detected by the second detecting means.

As described above, by detecting the light quantity in the specific wavelength band of the light reflected by the paper to be inspected by the first detecting means and by detecting the light quantity in the other wavelength band by the second detecting means. Light quantity data in two wavelength bands can be obtained at the same time.

The light quantity data detected by the first and second detecting means is given to the calculating means, and the light quantity data in the specific wavelength band is corrected using the light quantity data in the other wavelength bands. Then, the correction data obtained by the calculating means is given to the authenticity identifying means, and the authenticity of the sheet to be inspected is determined based on the correction data. In this way, since the authenticity of the paper sheet to be inspected is determined using the correction data, it is possible to determine the authenticity with high accuracy even if the paper sheet has poor reflection characteristics or absorption characteristics due to dirt or the like. .

That is, the degree of characteristic deterioration of paper sheets having poor reflection characteristics or absorption characteristics is substantially the same in the specific wavelength band and other wavelength bands. Therefore, by correcting the light amount data in the specific wavelength band using the light amount data in the other wavelength bands, the influence of characteristic deterioration can be removed. Therefore, the authenticity of the paper sheet can be identified with high accuracy regardless of the superiority or inferiority of the reflection characteristic or the absorption characteristic.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
It is a perspective view which shows the paper sheet authenticity identification apparatus 1 which concerns on embodiment of FIG. FIG. 2 is a schematic diagram showing the paper sheet authenticity identifying device 1. The paper sheet genuineness / counterfeiting device 1 is a device that is incorporated in a transport section of a bank sorting machine that processes banknotes at high speed and instantly determines the authenticity of banknotes. In addition, the paper sheet authenticity identification device 1
Can identify the authenticity of stamps, securities, and other papers in addition to banknotes.

As shown in FIG. 1, a paper sheet authenticity identifying device 1
Is provided with a rectangular parallelepiped light shielding case 10 having a reading window 11 provided on the upper surface 10a. A flat side plate 10b is fixed to the side portion of the light shielding case 10 with a screw. Inside the light shielding case 10, the beam splitter 1
2, 13, a mercury lamp 14, an ultraviolet filter 15,
An ultraviolet cut filter 16 and photosensors 17 and 18 are provided.

Next, the respective constituent members inside the light shielding case 10 will be specifically described. First, the beam splitter 12 is arranged below the reading window 11. The beam splitter 12 functions to reflect approximately 50% of incident light from the side and transmit approximately 50% of incident light from above. A tubular mercury lamp (irradiation means) 14 is arranged beside the beam splitter 12. The mercury lamp 14 irradiates the beam splitter 12 with light.

Here, the mercury lamp 14 can emit light having a spectrum in the ultraviolet band and the visible band as shown in FIG. A beam splitter (light splitting means) 13 is arranged below the beam splitter 12. The beam splitter 13 functions to transmit about 50% and reflect about 50% of visible light incident from above.

A disk-shaped ultraviolet cut filter (second wavelength-selective filter) 16 for allowing the light reflected by the beam splitter 13 to enter is disposed on the side of the beam splitter 13. As shown in FIG. 4, the ultraviolet cut filter 1
Reference numeral 6 functions to block light in the ultraviolet band and pass only light in the visible band. Further, behind the ultraviolet cut filter 16, a photo sensor (second detection means) 18 that makes visible light that has passed through the ultraviolet cut filter 16 incident and detects the amount of this visible light is disposed.

Below the beam splitter 13,
A disc-shaped ultraviolet filter (first wavelength-selective filter) 15 that allows the light transmitted through the beam splitter 13 to enter is arranged. As shown in FIG. 5, the ultraviolet filter 15 functions to pass only light in the ultraviolet band. further,
Below the ultraviolet filter 15, a photosensor (first detecting means) 17 that makes the ultraviolet light that has passed through the ultraviolet filter 15 incident and detects the light amount of this ultraviolet light is arranged.
Here, the photosensors 17 and 18 have a spectral sensitivity from the ultraviolet band to the visible band, as shown in FIG.

As shown in FIG. 2, photosensors 17, 1
Each light amount data detected in 8 is input to the authenticity determination unit 20. The authenticity determination unit 20 amplifies the current signals output from the photosensors 17 and 18 as light intensity data and converts them into voltage signals, and the amplifiers 21 and 22.
Taking the difference between the two voltage signals output from 1 and 22,
A differential amplifier (calculation means) 23 for correcting the light quantity data is provided. Further, the true / false determination unit 20 inputs the voltage signal output from the differential amplifier 23, inputs the comparator 24 that inverts the output when the voltage becomes equal to or higher than a predetermined level, and the output signal of the comparator 24, and outputs the output signal. And a discrimination circuit 25 for judging the authenticity of the bill based on the above. The comparator 24 and the discrimination circuit 25 constitute the authenticity discrimination means B.

Next, the operation of the paper sheet authenticity discriminating apparatus 1 according to this embodiment will be described with reference to FIGS. 1 and 2.

The paper sheet authenticity discriminating apparatus 1 is incorporated in the middle of a bill transport path (not shown), and the paper sheet is placed so that the transport surface of the bill transport path and the upper surface 10a of the light shielding case 10 are aligned with each other. The authenticity identification device 1 is arranged. Then, the banknotes (paper sheets to be inspected) A moving on the banknote transport path are light-shielding cases 10.
When the banknote A reaches the upper surface 10a of the sheet A and covers the reading window 11, the paper sheet authenticity identifying apparatus 1 starts the identifying operation.

That is, the arrival of the bill A on the reading window 11 is detected by an arrival detection sensor (not shown) arranged in front of the reading window 11, and a detection signal from the arrival detection sensor is received. The mercury lamp 14 emits light. The light emitted from the mercury lamp 14 is reflected by the beam splitter 12 and goes straight toward the reading window 11. Since the bill A exists on the reading window 11, the light reflected by the beam splitter 12 is reflected on the surface of the bill A.

The reflected light goes straight downward and is transmitted through the beam splitter 12. The light transmitted through the beam splitter 12 enters the beam splitter 13 and is split into two directions.
That is, about half of the light incident on the beam splitter 13 passes through the beam splitter 13 and travels straight downward, and the remaining light is reflected by the beam splitter 13 and travels laterally. The light transmitted through the beam splitter 13 enters the ultraviolet filter 15, and only the light in the ultraviolet band (specific wavelength band) passes through the ultraviolet filter 15. Then, the ultraviolet light that has passed through the ultraviolet filter 15 is incident on the photo sensor 17, and the light amount of this ultraviolet light is detected by the photo sensor 17.

As shown in FIG. 7, the genuine bill is made of special ink having a high light reflectance in the ultraviolet band (specific wavelength band). On the other hand, the counterfeit banknote is made of general ink having a low light reflectance in the ultraviolet band. Therefore, when the banknote A is a genuine banknote, the amount of light in the ultraviolet band in the reflected light reflected on the surface of the banknote A is large, and the light in these ultraviolet bands passes through the ultraviolet filter 15 and is incident on the photosensor 17. . Therefore, the amount of incident light detected by the photo sensor 17 is large. On the other hand, when the banknote A is a counterfeit banknote, the reflected light reflected on the surface of the banknote A has a small amount of light in the ultraviolet band, and a large amount of light is reflected by the ultraviolet filter 15. Therefore, the amount of incident light detected by the photo sensor 17 is small.

On the other hand, the light reflected by the beam splitter 13 enters the ultraviolet cut filter 16, and only the light in the visible band (other wavelength band) passes through the ultraviolet cut filter 16. Then, the visible light that has passed through the ultraviolet cut filter 16 is incident on the photo sensor 18, and the amount of this visible light is detected by the photo sensor 18. Since the light reflectance in the visible band is almost equal between the special ink and the general ink (see FIG. 7), the light amount detected by the photo sensor 18 is almost the same whether the banknote A is an authentic banknote or a counterfeit banknote. Is.

When the light intensity of the incident light is detected by the photo sensor 17, a current signal corresponding to this light intensity data (light intensity data in a specific wavelength band) is output from the photo sensor 17. Then, the current signal output from the photo sensor 17 is input to the amplifier 22, and this current signal is amplified and converted into a voltage signal. Similarly, when the light intensity of the incident light is detected by the photo sensor 18, a current signal corresponding to this light intensity data (light intensity data in another wavelength band) is output from the photo sensor 18. Then, the current signal output from the photo sensor 18 is input to the amplifier 21, and this current signal is amplified.

The amplification levels of the amplifiers 21 and 22 are adjusted so that the output levels are the same when the bill A is a genuine bill. As a result, when the bill A is a genuine bill, the output of the amplifier 21 and the output of the amplifier 22 are at the same level. On the other hand, when the banknote A is a counterfeit banknote, the amount of light detected by the photosensor 17 is small and the amount of light detected by the photosensor 18 is the same as that of a genuine banknote, and therefore the amplifier 22 The output will be lower than the output of the amplifier 21.

The voltage signals output from the amplifiers 21 and 22 are input to the differential amplifier 23. In the differential amplifier 23,
The voltage signal (light amount data in a specific wavelength band) input from the amplifier 22 is subtracted by the voltage signal (light amount data in another wavelength band) input from the amplifier 21. The voltage signal (correction signal) output from the differential amplifier 23 is input to the comparator 24, and the comparator 2
At 4, when the voltage signal exceeds a predetermined level, the output is inverted. The output signal from the comparator 24 is input to the identification circuit 25, and the identification circuit 25 determines the authenticity of the bill A based on the level of the output signal.

That is, when the banknote A is a genuine banknote, the voltage signals input from the amplifiers 21 and 22 to the differential amplifier 23 have the same level, and thus the level of the voltage signal output from the differential amplifier 23 is low. Become. This low-level voltage signal is given to the comparator 24, and the comparator 24 outputs a low-level signal. On the other hand, when the banknote A is a counterfeit banknote, the levels of the voltage signals input from the amplifiers 21 and 22 to the differential amplifier 23 are different,
The level of the voltage signal output from the differential amplifier 23 becomes high. This high-level voltage signal is given to the comparator 24, and the comparator 24 outputs a high-level signal.

Then, in the discrimination circuit 25, the comparator 2
When the input signal from 4 is low level, it is determined that the banknote A is a genuine banknote, and when the input signal from the comparator 24 is high level, it is determined that the banknote A is a counterfeit banknote. By such a determination, the authenticity of the bill A can be accurately identified.

By the way, genuine banknotes having a low reflectance of ultraviolet light due to stains such as hand stains and poor quality of special ink have poor discrimination accuracy because the amount of reflected ultraviolet light is not so different from that of counterfeit banknotes. Therefore, in the paper sheet genuine / counterfeiting device 1, the banknote is irradiated with light in the wavelength band from visible to ultraviolet, and the amount of light in the ultraviolet band (specific wavelength band) of the reflected light and the visible band (other By correcting the difference between the light amount of light in the wavelength band), the genuine bill with the reduced reflectance of ultraviolet light is corrected.

In other words, genuine bills that have been stained with hand marks or genuine bills printed with poor quality special ink have a lower light reflectance in the ultraviolet band than ordinary bills, but also have a light reflectance in the visible band. It decreases at the same ratio as the light reflectance in the ultraviolet band. Therefore, by taking the difference between the light amount data of the light in the ultraviolet band and the light amount data of the light in the visible band, the decrease in the light amount due to the decrease in the light reflectance will be canceled by the light amount data of each other, and the light reflectance will decrease. The effect of can be removed. For this reason, it is possible to discriminate the authenticity of banknotes that have been soiled with dirt or the like and banknotes that have been printed with poor quality special ink with high accuracy, as with ordinary banknotes.

(Second Embodiment) FIG. 8 shows a second embodiment of the present invention.
FIG. 3 is a schematic view showing a paper sheet authenticity identification device 2 according to the exemplary embodiment. The second embodiment is different from the first embodiment shown in FIG. 2 in that (1) the tungsten light source 30 is provided instead of the mercury lamp 14, and (2) the photosensors 17 and 18 are provided. Instead, the photosensors 50 and 51 are provided, and (3) the infrared filter 40 is provided instead of the ultraviolet filter 15, and the infrared cut filter 41 is provided instead of the ultraviolet cut filter 16. (4) Authentic banknotes are made with special black ink that has a high light reflectance even in the infrared band. Other configurations are the same as or equivalent to those in the first embodiment.

Here, as shown in FIG. 9, the tungsten light source (irradiating means) 30 can irradiate light in the wavelength band from visible to infrared. Further, as shown in FIG. 10, the photosensors 40 and 41 have spectral sensitivity in the wavelength band from visible to infrared. Further, as shown in FIG. 11, the genuine bill is made of special black ink whose light reflectance in the infrared band (specific wavelength band) is higher than that of general black ink. It is made with general black ink. Therefore, when the banknote A is a genuine banknote,
The reflected light reflected on the surface of the bill A has a large amount of light in the infrared band. When the banknote A is a counterfeit banknote, the amount of light in the infrared band in the reflected light reflected on the surface of the banknote A is small. In addition, the same or equivalent components as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 8, the light reflected on the surface of the bill A passes through the beam splitter 12 and enters the beam splitter 13. Then, the light incident on the beam splitter 13 is transmitted or reflected by the beam splitter 13 and is branched into two directions. The light transmitted through the beam splitter 13 is an infrared filter (first wavelength selective filter) 40.
Incident on. The infrared filter 40 has a characteristic of transmitting only light in the infrared band (specific wavelength band) as shown in FIG. Therefore, only the light in the infrared band passes through the infrared filter 40 and the photo sensor (first detecting means) 50
Incident on the photo sensor 50.
Is detected by As described above, when the banknote A is a genuine banknote, the amount of light in the infrared band is large, and thus the amount of light detected by the photosensor 50 is large. On the other hand, when the banknote A is a counterfeit banknote, the amount of light in the infrared band is small, so the amount of light detected by the photosensor 50 is small.

The light reflected by the beam splitter 13 is an infrared cut filter (second wavelength selective filter) 4
Incident on 1. The infrared cut filter 41 has a characteristic of blocking light in the infrared band (specific wavelength band) as shown in FIG. Therefore, visible band (other wavelength band)
Of the light passes through the infrared cut filter 41 and is incident on the photosensor (second detection means) 51, and the photosensor 51 detects the amount of light in the visible band. Here, since the light reflectance in the visible band is almost equal between the special ink and the general ink (see FIG. 11), the amount of light detected by the photo sensor 51 regardless of whether the bill A is an authentic bill or a counterfeit bill. Are almost the same.

When the light intensity of the incident light is detected by the photosensors 50 and 51, current signals corresponding to the light intensity data are output from the photosensors 50 and 51. Then, the current signals output from the photosensors 50 and 51 are input to the amplifiers 21 and 22 and these current signals are amplified. The amplification degrees of the amplifiers 21 and 22 are adjusted so that the output levels are the same when the banknote A is a counterfeit banknote.
As a result, when the banknote A is a counterfeit banknote, the output of the amplifier 21 and the output of the amplifier 22 are at the same level. On the other hand, when the banknote A is a genuine banknote, the photo sensor 4
Since the amount of light detected by 0 is large and the amount of light detected by the photo sensor 41 is the same, the output of the amplifier 22 is higher than the output of the amplifier 21.

The voltage signals output from the amplifiers 21 and 22 are input to the differential amplifier 23. In the differential amplifier 23,
The voltage signal (light amount data in a specific wavelength band) input from the amplifier 22 is subtracted by the voltage signal (light amount data in another wavelength band) input from the amplifier 21. The voltage signal (correction signal) output from the differential amplifier 23 is input to the comparator 24, and the comparator 2
At 4, when the voltage signal exceeds a predetermined level, the output is inverted. The output signal from the comparator 24 is input to the identification circuit 25, and the identification circuit 25 determines the authenticity of the bill based on the level of the output signal.

That is, when the banknote A is a genuine banknote, the level of the voltage signal input from the amplifiers 21 and 22 to the differential amplifier 23 is different, and the level of the voltage signal output from the differential amplifier 23 is high. Become. This high-level voltage signal is given to the comparator 24, and the comparator 24 outputs a high-level signal. On the other hand, when the banknote A is a counterfeit banknote, the levels of the voltage signals input from the amplifiers 21 and 22 to the differential amplifier 23 are the same,
The level of the voltage signal output from the differential amplifier 23 becomes low. This low-level voltage signal is given to the comparator 24, and the comparator 24 outputs a low-level signal.

Then, the discrimination circuit 25 determines that the banknote A is an authentic banknote when the input signal from the comparator 24 is at a high level, and the banknote A is a counterfeit banknote when the input signal from the comparator 24 is at a low level. It is determined that By such a determination, the authenticity of the bill A can be accurately identified.

As described above, in the paper sheet authenticity discriminating device 2, the difference between the light amount of light in the infrared band (specific wavelength band) and the light amount of light in the visible band (other wavelength bands) is calculated to obtain the red color. Corrections are made for banknotes that have reduced external light reflectance. For this reason, even a banknote having a reduced reflectance of infrared light due to stains on hands and the like can be identified with high accuracy as with a normal banknote.

It should be noted that the present invention is not limited to the above embodiment, but can be modified as follows, for example, without departing from the spirit of the present invention.

(1) In the above embodiment, genuine bills printed with a special ink having a high light reflectance in the ultraviolet band or the infrared band are targeted for identification. However, a special bill having a light reflectance in the ultraviolet band different from that of general paper is used. Authentic banknotes using paper may be used as the identification target. Further, a genuine bill using a special paper whose light reflectance in the infrared band is different from general paper may be used as the identification target.

(2) In the above embodiment, the differential amplifier 23
Is used to correct the light amount data based on the difference between the two voltage signals, but a known circuit is used instead of the differential amplifier 23 to correct the light amount data based on the ratio of the two voltage signals. You can go.

[0045]

As described in detail above, the paper sheet authenticity discriminating apparatus of the present invention makes the light reflected by the paper sheet to be inspected enter and only the light in the specific wavelength band of this incident light is emitted. The first wavelength-selective filter to be passed, the first detection means for detecting the amount of light passing through the first wavelength-selective filter, and the light reflected by the paper sheet to be inspected is made to enter the incident light. A second wavelength-selective filter that allows only light in another wavelength band of light to pass, a second detector that detects the amount of light that has passed through the second wavelength-selective filter, and a first detector. A calculation unit that subtracts the light amount data detected by the second detection unit from the detected light amount data to obtain correction data, and a true / false determination of the authenticity of the paper sheet to be inspected based on the correction data obtained by the calculation unit. And false identification means.

As described above, since the authenticity discriminating means judges the authenticity of the paper sheet to be inspected by using the correction data, even if the paper sheet has a bad reflection characteristic or absorption characteristic due to dirt or the like, high accuracy is obtained. You can identify the truth. That is, the degree of characteristic deterioration of paper sheets having poor reflection characteristics or absorption characteristics is substantially the same in the specific wavelength band and other wavelength bands. Therefore, by correcting the light amount data in the specific wavelength band using the light amount data in the other wavelength bands, the influence of characteristic deterioration can be removed. Therefore, the authenticity of the paper sheet can be identified with high accuracy regardless of the superiority or inferiority of the reflection characteristic or the absorption characteristic.

[Brief description of drawings]

FIG. 1 is a perspective view showing a paper sheet authenticity identification device according to a first embodiment.

FIG. 2 is a schematic view showing a paper sheet authenticity discrimination device according to the first embodiment.

FIG. 3 is a diagram showing light emission characteristics of a mercury lamp.

FIG. 4 is a diagram showing a light transmission characteristic of an ultraviolet cut filter.

FIG. 5 is a diagram showing a light transmission characteristic of an ultraviolet filter.

FIG. 6 is a diagram showing the spectral sensitivity of a photo sensor.

FIG. 7 is a diagram showing spectral reflection characteristics of special ink and general ink.

FIG. 8 is a schematic diagram showing a paper sheet authenticity discrimination device according to a second embodiment.

FIG. 9 is a diagram showing a light emission characteristic of a tungsten light source.

FIG. 10 is a diagram showing the spectral sensitivity of a photo sensor.

FIG. 11 is a diagram showing spectral reflection characteristics of special ink and general ink.

FIG. 12 is a diagram showing a light transmission characteristic of an infrared filter.

FIG. 13 is a diagram showing a light transmission characteristic of an infrared cut filter.

[Explanation of symbols]

1, 2 ... Paper true / false identification device, 13 ... Beam splitter (light splitting means), 14 ... Mercury lamp (irradiation means), 15
... UV filter (first wavelength selective filter), 16 ...
UV cut filter (second wavelength selective filter), 1
7, 50 ... Photo sensor (first detection means), 18, 5
DESCRIPTION OF SYMBOLS 1 ... Photo sensor (2nd detection means), 20 ... True / false determination part, 23 ... Differential amplifier (arithmetic means), 25 ... Identification circuit,
30 ... Tungsten light source (irradiating means), 40 ... Infrared filter (first wavelength selective filter), 41 ... Infrared cut filter (second wavelength selective filter), A ... Banknote (paper sheet to be inspected) , B ... Authenticity identification means.

Claims (1)

[Claims] 1. A paper sheet authenticity discriminating apparatus for discriminating the authenticity of an inspected paper sheet printed with a special ink having a light reflectance in a specific wavelength band different from that in other wavelength bands, Irradiation means for irradiating the paper sheet to be inspected with light having a wavelength component of a specific wavelength band and a wavelength component of the other wavelength band, and an optical branching device for branching the light reflected by the paper sheet to be inspected into two directions. Means, a first wavelength-selective filter that allows one of the light beams branched by the light branching device to enter, and allows only the light of the incident light in the specific wavelength band to pass, and the other of the other light beams branched by the light branching device. A second wavelength-selective filter that allows light to enter and allows only light in other wavelength bands of the incident light to pass through, and light that has passed through the first wavelength-selective filter to enter the incident light A first detecting means for detecting the amount of light; and a second wavelength selective flux. The second detection means for injecting the light passing through the filter and detecting the light quantity of the incident light; and the second light quantity data based on the light quantity data detected by the first detection means.
Calculating means for obtaining correction data by subtracting the light amount data detected by the detecting means, and authenticity identifying means for identifying the authenticity of the paper sheet to be inspected based on the correction data obtained by the calculating means. A paper sheet authenticity identification device characterized by comprising: