JP2003263667A - Paper sheet fluorescence detection sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper sheet fluorescence detection sensor for precisely receiving fluorescence generated from a paper sheet without being affected by the condition of the paper sheet. <P>SOLUTION: This sensor uses a visible light reflecting filter 15 to simultaneously fulfill the emission of ultraviolet rays to a direction orthogonal to a carriage path 4 and the proper reception of fluorescence from a paper sheet 7. This visible light reflecting filter 15 is made to transmit ultraviolet rays among lights emitted from an ultraviolet light source 12, and to reflect visible lights in order to create ultraviolet rays having an optical axis R1 orthogonal to a carriage path 4. Then, the fluorescence emitted from the paper sheet 7 by lights transmitted through the visible light reflecting filter 15 is reflected by the visible light reflecting filter 15, and then received by a fluorescence receiving element 16. Furthermore, an ultraviolet ray absorbing filter 17 disposed between the visible light reflecting filter 15 and the fluorescence receiving element 16 is made to cut ultraviolet components made incident to the fluorescence receiving element 16 so that the light receiving precision can be improved. Also, a paper sheet fluorescence detecting sensor using the visible light reflecting filter 15 is configured so as to be suitable for reducing the number of filters, and so as to be easy to promote miniaturization. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper sheet fluorescence detection sensor for use in determining the type and authenticity of paper sheets such as banknotes.

[0002]

2. Description of the Related Art Conventionally, as a technique in such a field, there is Japanese Patent Publication No. 9-507326. The device described in this publication irradiates a bill with ultraviolet rays and measures the level of ultraviolet light reflected by the bill using a first photocell, and at the same time, measures the amount of fluorescence generated in the bill by a second amount. Measure with a photocell, compare each measured amount with a reference level,
This is to distinguish the authenticity of bills.

[0003]

However, the conventional device described above has the following problems. That is, when the bills are irradiated with ultraviolet rays obliquely from above, it is possible to receive light relatively appropriately for flaps of the bills on the transport path, but the bills are wrinkled or folded. In this state, the required range of the bill will not be sufficiently irradiated with ultraviolet light. In this case, the generated fluorescence becomes uneven, and as a result, the received light output of the fluorescence tends to become uneven, and it is difficult to accurately receive the fluorescence.

The present invention has been made in order to solve the above-mentioned problems, and in particular, the fluorescence of paper sheets is made to accurately receive the fluorescence emitted from the paper sheets, and the fluorescence of the paper sheets is not easily influenced by the state of the paper sheets. An object is to provide a detection sensor.

[0005]

A paper sheet fluorescence detection sensor according to the present invention detects a fluorescence emitted from a paper sheet by irradiating the paper sheet with light while the paper sheet is being conveyed. In the fluorescence detection sensor, the ultraviolet light source housed in the housing, and while being housed in the housing, transmits the ultraviolet light emitted from the ultraviolet light source and reflects the visible light, with respect to the conveyance path of the paper sheet. A visible light reflection filter that irradiates UV rays so that they intersect at right angles, and a fluorescent light receiving element that is housed in the housing and that receives the UV light that reflects the fluorescence emitted from the paper sheets by the visible light reflection filter and receives the visible light. An ultraviolet absorption filter arranged between the reflection filter and the fluorescent light receiving element is provided.

In this paper sheet fluorescence detection sensor, the paper sheet is irradiated with ultraviolet rays, and the fluorescence emitted from the paper sheet is received by the fluorescence receiving element to detect the type and authenticity of the paper sheet. This is an invention that is premised on discrimination. In addition, the paper sheets on the conveyance path are not always conveyed in a constant state, and may be flapping on the conveyance path, or the paper sheets themselves may be wrinkled or folded. is there. In any of these situations, it is necessary to make it difficult to cause unevenness in the output from the fluorescent light receiving element. Therefore, in the present invention, the visible light reflection filter is used in order to satisfy both the application of the ultraviolet rays in the direction orthogonal to the transport path and the appropriate reception of the fluorescence from the paper sheets. This visible light reflection filter transmits the ultraviolet light of the light emitted from the ultraviolet light source and reflects the visible light to produce ultraviolet light having an optical axis orthogonal to the paper sheet conveyance path. . Then, the fluorescence emitted from the paper sheet by the light transmitted through the visible light reflection filter is reflected by the visible light reflection filter and then received by the fluorescence light receiving element. Further, in the present invention, the ultraviolet absorption filter arranged between the visible light reflection filter and the fluorescence light receiving element cuts off the ultraviolet light component incident on the fluorescence light receiving element to improve the light receiving accuracy. Further, it can be said that the paper sheet fluorescence detection sensor using the visible light reflection filter is suitable for a structure that reduces the number of filters and is a structure that facilitates miniaturization.

Further, it is preferable to include an illumination monitor housed in the housing and receiving the light emitted from the ultraviolet light source and reflected by the visible light reflection filter. When such a configuration is adopted, the light irradiating the paper sheet in the middle of conveyance cannot be accurately discriminated (for example, the type of bill and the authenticity) unless the light is constantly managed in a constant state. There is a fear that the illumination monitor is arranged in the housing in order to eliminate such a problem.

Further, the visible light reflection filter is arranged in the housing at an angle so that the fluorescence emitted from the paper sheet is bent 90 degrees toward the fluorescence receiving element, and the ultraviolet light source is arranged on the optical axis orthogonal to the conveying path. Is preferably arranged, and the illumination monitor is arranged on the extension of the optical axis of the fluorescent light receiving element. Such a configuration makes it possible to optimize the layout of each component in the housing in the present invention using the visible light reflection filter.

Further, it is preferable that the ultraviolet light source includes a lens portion for controlling the light directed to the visible light reflection filter so that the illumination area is substantially the same as the light receiving area on the transport path. Such a configuration is optimal for effectively utilizing the ultraviolet rays applied to the paper sheets when receiving the fluorescence, and this is easily and surely achieved by providing a lens portion in the ultraviolet light source. .

Further, it is preferable that the fluorescent light receiving element includes a lens portion for controlling the light reflected by the visible light reflection filter and directed to the fluorescent light receiving element so that the light receiving area is substantially the same as the illuminated area on the transport path. Is. Such a configuration
This is optimum for effectively utilizing the ultraviolet rays applied to the paper sheets when receiving the fluorescence, and this is easily and surely achieved by providing the lens portion in the fluorescence receiving element.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a paper sheet fluorescence detection sensor according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing a paper sheet inspection device 1. What is inspected by the paper sheet inspection device 1 is:
This is true / counterfeit discrimination of banknotes, which is an example of paper sheets, and specifically, discrimination between color-copied counterfeit banknotes and legitimate banknotes. This color copy paper contains a large amount of fluorescent component, and attention is paid to this point to make a true / false decision.

The paper sheet inspection device 1 includes an upper and lower guide plates 2,
Linear transport path 4 formed so as to be sandwiched by 3
Is provided, and conveyance rollers 5 and 6 are arranged in the middle of the conveyance path 4, and the bills 7 are formed by the conveyance rollers 5 and 6.
Is reliably transported toward the discharge side. A bill recognition device 8 for identifying a denomination is arranged in the middle of the transport path 4.

Although not shown, the bill (paper sheet) recognition device 8 has a structure in which the bill 7 is illuminated by a light source such as an LED and the reflected light from the bill 7 is captured by a CCD camera. Then, the image captured by the camera and the known image data are collated to determine the denomination of the bill. However, in recent years, due to the high precision of color copying, it is difficult to determine the authenticity of the bill 7 only by image recognition.

Therefore, the paper sheet fluorescence detection sensor 10 is arranged on the upstream side of the bill recognition device 8. As shown in FIG. 2, this paper sheet fluorescence detection sensor 10 has a partitioning portion 20 that vertically divides the internal space of a substantially rectangular parallelepiped housing 11. The partition section 20 divides the ultraviolet light source 12 and the fluorescent light receiving element 16 and divides the housing 11 into a first compartment 23 and a second compartment 24. And
In the housing 11, the first part formed by the partition part 20
An ultraviolet light source 12 composed of an ultraviolet LED (light emitting element) is housed in the compartment 23 of the.
It is fixed so as to be hung from the drive circuit board 25 attached to the housing 11 via the lead portion 12a.

The ultraviolet light source 12 used here is an ultraviolet LED containing a visible light component. Further, the reason why the LED is adopted as the light source is that the housing 11 has a small accommodation space even if the housing 11 is small, has a small variation in brightness, and has little light fluctuation with time. Paper sheet fluorescence detection sensor 10
Is perfect for.

A fluorescent light receiving element (photosensor) 16 for detecting the fluorescent light emitted from the bill 7 is housed in the second compartment 24. The light receiving element 16 is provided in the lead section 1.
It is fixed so as to be hung on the drive circuit board 25 via 6a. In addition, on the lower surface of the housing 11, the second compartment 24
The dustproof glass plate 14 is fixed with an adhesive or the like so as to block the glass. The dustproof glass plate 14 is made of glass that easily transmits ultraviolet rays.

Further, the ultraviolet LED 12 and the dustproof glass plate 1
The visible light reflection filter 15 is fixed to the housing 11 with an adhesive or the like in the opening 20a of the partition 20 provided between the housing 11 and the partition 4. As the visible light reflection filter 15, a filter having a characteristic of transmitting ultraviolet rays and reflecting visible light is adopted. Therefore, the light emitted from the ultraviolet LED 12 is reflected by the visible light reflection filter 1
By passing through 5, the ultraviolet component (for example 300 ~
About 400 nm) is released into the second compartment 24. By adopting such a visible light reflection filter 15, the ultraviolet ray content is increased and the light receiving accuracy is improved.

When the fluorescence emitted from the bill 7 is detected by using the ultraviolet light source 12 and the fluorescent light receiving element 16, the bill 7 on the conveying path 4 is not always conveyed in a constant state, but is conveyed on the conveying path. There are cases where flapping occurs on the sheet 4, wrinkles S occur on the banknote 7 itself, and folds P occur. Even under such a situation, the fluorescent light receiving element 1
It is necessary to make unevenness in the output from 6 difficult.

Therefore, the visible light reflection filter 15 is used in order to simultaneously satisfy the application of the ultraviolet rays in the direction orthogonal to the conveyance path 4 and the appropriate reception of the fluorescence from the banknote 7. This visible light reflection filter 15
Is disposed between the ultraviolet light source 12 and the dustproof glass plate 14, and the ultraviolet light source 12 is oriented so that its optical axis R1 (see FIG. 3) is orthogonal to the transport path 4. Further, the visible light reflection filter 15 directs the fluorescent light emitted from the banknote 7 by the irradiation of ultraviolet rays toward the fluorescent light receiving element 16.
It is fixed to the partition portion 20 of the housing 11 at an angle (for example, 45 degrees with respect to the transport path 4) that causes the reflection. That is, the reflection surface of the visible light reflection filter 15 is located at the intersection where the optical axis R2 of the fluorescent light receiving element 16 and the optical axis R1 of the ultraviolet light source 12 are orthogonal to each other, and the optical axis R1 is orthogonal to the transport path 4. .

Therefore, it is possible to cope with the fluttering of the banknotes 7 on the transport path 4, and even if the banknotes 7 have wrinkles S or folds P, the wrinkles S or the folds P are not formed. In the above, the fluorescence unevenness generated by suppressing the irradiation unevenness of the ultraviolet light does not occur. As a result, it is possible to improve the accuracy of receiving fluorescence. When the banknote 7 illuminated by ultraviolet rays contains a fluorescent component, excited fluorescence is emitted from the banknote 7, and this fluorescence is reflected by the visible light reflection filter 15 along the optical axis R1. After that, it is detected by the fluorescent light receiving element 16 along the optical axis R2. For example, when the color-copied counterfeit banknote 7 is fed into the conveyance path 4, the color copy paper contains a large amount of fluorescent components, and therefore the amount of fluorescence detected by the light receiving element 16 is high. Become. On the other hand, a regular bill contains almost no fluorescent component, and the light receiving element 16
The detection amount of is extremely small. Further, it can be said that the paper sheet fluorescence detection sensor 10 using the visible light reflection filter 15 described above is suitable for a structure that reduces the number of filters and is a structure that facilitates miniaturization.

An ultraviolet absorption filter 17 is attached to the fluorescent light receiving element 16 between the visible light reflection filter 15 and the fluorescent light receiving element 16. The reason why such an ultraviolet absorption filter 17 is adopted is that the fluorescent light receiving element 16 is used.
This is because the light that is about to enter is sometimes included in a relatively large amount of ultraviolet components, and the excess ultraviolet components are cut to improve the accuracy of light reception.

Further, the amount of light applied to the banknotes 7 being conveyed may not be accurately inspected (for example, banknote type and authenticity) unless the amount of light applied to the banknotes 7 is constantly controlled. Therefore, as a means of managing the same, the visible light reflection filter 15 is controlled by the illumination monitor 18 including a photo sensor.
The light reflected by is received. This lighting monitor 18 is
The visible light reflected by the visible light reflection filter 15 is reliably captured while being housed in the compartment 23 and arranged on an extension of the optical axis R2 (see FIG. 3). The illumination monitor 18 also includes a drive circuit board 25 via the lead portion 18a.
It is fixed to. Therefore, the light emitted from the ultraviolet light source 12 is indirectly received by the illumination monitor 18 via the visible light reflection filter 15.

Further, when the ultraviolet rays applied to the bill 7 in the state as shown in FIG. 2 are effectively used, it is preferable that the illumination area A and the light receiving area B are substantially the same on the transport path 4 (FIG. 3). Therefore, the lens portion 33 is provided at the tip of the ultraviolet LED 12. When the light receiving area B is known in advance, the lens portion 33 is used to adjust the illumination angle of the ultraviolet LED 12 to control the light traveling toward the transport path 4, and the optimum brightness has the light receiving area B. As shown in B, various selections are made according to the characteristics of the ultraviolet LED 12. By using the lens portion 33 as described above, ultraviolet rays L
The illumination angle of the ED 12 can be adjusted easily and reliably.

The present invention is not limited to the above embodiment. For example, another paper sheet fluorescence detection sensor 40
Then, as shown in FIG. 4, in order to effectively utilize the ultraviolet rays applied to the banknote 7 (see FIG. 2), in order to make the illumination area A and the light receiving area B substantially the same on the conveyance path 4, The ultraviolet absorption filter 17 is sandwiched between the light receiving element 16 and the lens portion 35. This lens part 3
5 is used for adjusting the light receiving angle of the fluorescent light receiving element 16 and controlling the fluorescent light toward the light receiving portion of the fluorescent light receiving element 16 when the illumination area A is known in advance. The lens unit 35 is variously selected according to the characteristics of the fluorescent light receiving element 16 so that the optimum light receiving region B can be obtained.
By using such a lens portion 35, the optimum light receiving area B can be easily and surely created.

When the ultraviolet light source 12 having high directivity is used, the lens portion 33 is not necessary. Further, the lens portion 33 may be arranged in front of the ultraviolet light source 12 and the lens portion 35 may be arranged in front of the fluorescence light receiving element 16.

[0027]

The paper sheet fluorescence detection sensor according to the present invention comprises:
Since it is configured as described above, the following effects are obtained. That is, in the middle of transporting the paper sheet, in the paper sheet fluorescence detection sensor that irradiates the paper sheet with light and detects the fluorescence emitted from the paper sheet, the ultraviolet light source housed in the housing and the inside of the housing. A visible light reflection filter, which is housed, transmits ultraviolet light emitted from an ultraviolet light source, reflects visible light, and irradiates ultraviolet light so as to be orthogonal to the paper sheet conveyance path, and is housed in the housing. In addition, it is provided with a fluorescence receiving element that receives fluorescence by reflecting the fluorescence emitted from the paper sheet by irradiation of ultraviolet rays with a visible light reflection filter, and an ultraviolet absorption filter arranged between the visible light reflection filter and the fluorescence reception element. As a result, it is possible to realize a paper sheet fluorescence detection sensor that can accurately receive the fluorescence emitted from the paper sheet and that is not easily affected by the state of the paper sheet.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a paper sheet inspection device to which a paper sheet fluorescence detection sensor according to the present invention is applied.

FIG. 2 is a sectional view showing a first embodiment of a paper sheet fluorescence detection sensor according to the present invention.

3 is a cross-sectional view showing an illumination region and a light receiving region of the sensor shown in FIG.

FIG. 4 is a sectional view showing a second embodiment of a paper sheet fluorescence detection sensor according to the present invention.

[Explanation of symbols]

4 ... Conveyance path, 7 ... Banknote (paper sheet), 10, 40 ... Paper sheet fluorescence detection sensor, 11 ... Housing, 12 ... Ultraviolet LED
(UV light source), 15 ... Visible light reflection filter, 16 ... Fluorescent light receiving element, 17 ... UV absorption filter, 18 ... Illumination monitor, 33, 35 ... Lens part, A ... Illumination area, B ... Light receiving area, R1, R2 ... optical axis.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazunori Hirose             2-18-10 Shimura, Itabashi-ku, Tokyo Nidec             Sankopal Co., Ltd. (72) Inventor Mitsuyo Usami             2-18-10 Shimura, Itabashi-ku, Tokyo Nidec             Sankopal Co., Ltd. F term (reference) 3E041 AA02 AA03 AA04 BB03 BB04                       BB05 BC04 EA01 EA03 EA05

Claims (5)

[Claims] 1. A paper sheet fluorescence detection sensor for irradiating the paper sheet with light during transportation of the paper sheet to detect fluorescence emitted from the paper sheet, wherein the ultraviolet light source is housed in a housing. A visible light reflection that allows the ultraviolet light emitted from the ultraviolet light source to pass through and reflects the visible light while being housed in the housing, and irradiates the ultraviolet light so as to be orthogonal to the conveyance path of the paper sheet. A filter, a fluorescent light receiving element that is housed in the housing, receives fluorescence by irradiating the ultraviolet rays from the paper sheet by reflecting the fluorescent light with the visible light reflection filter, and receives the visible light reflection filter and the fluorescence reception light. A paper sheet fluorescence detection sensor comprising an ultraviolet absorption filter arranged between the element and the element. 2. An illumination monitor, which is housed in the housing and receives light emitted from the ultraviolet light source and reflected by the visible light reflection filter.
The paper sheet fluorescence detection sensor described. 3. The visible light reflection filter is arranged in the housing at an angle such that the fluorescence emitted from the paper sheet is bent 90 degrees toward the fluorescence receiving element, and the visible light reflection filter is orthogonal to the transport path. 3. The paper sheet fluorescence detection sensor according to claim 2, wherein the ultraviolet light source is arranged on the axis, and the illumination monitor is arranged on an extension of the optical axis of the fluorescence light receiving element. 4. The ultraviolet light source includes a lens unit that controls light directed to the visible light reflection filter so that the ultraviolet light source has an illumination area substantially the same as a light receiving area on the transport path. Item 5. The paper sheet fluorescence detection sensor according to any one of Items 1 to 3. 5. The lens section for controlling the light reflected by the visible light reflection filter toward the fluorescence light receiving element so that the fluorescence light receiving element has a light receiving area substantially the same as an illumination area on the transport path. The paper sheet fluorescence detection sensor according to any one of claims 1 to 4, further comprising: