JP2002183795A - Paper sheet detecting sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper sheet detecting sensor having a lower cost by reducing the number of lens parts. SOLUTION: The paper sheet detecting sensor 10 comprises a light emitting element 12 and a light receiving element 16 parted in a casing 11 with a partitioning part 30 to prevent interference with each other. The field of view of the light receiving element 16 is interrupted by the partitioning part 30, thereby simply and surely creating a desirable limited field of view. Namely, to maintain the desirable limited field of view, the light receiving element 16 having a wider field of view than a light receiving element has a corresponding field of view is adopted for active interruption of the field of view by the partitioning part 30. Therefore, the influence of the up-and-down movement of paper sheets is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as a technique in such a field, a light receiving element is arranged at the center of a housing, LEDs are arranged so as to sandwich the light receiving element, light from the LED is irradiated on a bill, and then reflected by the bill. There is known a paper sheet detection sensor that detects light emitted by a light receiving element. Further, the bill being conveyed has “up and down” occurring in the reading area of the light receiving element, whereby the light receiving amount of the light receiving element changes with a change in the reading depth, which causes a detection error. was there. Therefore, a rod lens is disposed in front of the light receiving element in the housing, and the influence of the vertical movement of the bill during light reception is reduced by this rod lens as much as possible.

[0003]

However, the above-mentioned conventional paper sheet detection sensor has the following problems. That is, the adoption of the rod lens described above
Even if bills move up and down during transportation, the accuracy of detection by the light receiving element is improved, but the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a paper sheet detection sensor capable of reducing costs by reducing the number of lens parts.

[0005]

A sheet detecting sensor according to the present invention irradiates light to the sheet while the sheet is being conveyed, and receives light from the surface of the sheet. In the paper sheet detection sensor, a light emitting element that is housed in a housing and irradiates light toward a paper sheet transport path, and that is housed in a housing and receives light from the surface of the paper sheet A light receiving element,
With a partition part for separating the light receiving element and the light emitting element,
The light receiving element is arranged facing the partition, and the field of view of the light receiving element is limited by the partition.

In this paper sheet detection sensor, the light emitting element and the light receiving element are separated from each other in the housing by a partition so that they do not interfere with each other. Then, by blocking the field of view of the light receiving element with the partition, a restricted desired field of view is easily and reliably created. Certainly, if a light receiving element with a narrow field of view is used, light from paper sheets can be spot-received without limiting the field of view, and light receiving efficiency can be improved. The smaller the distance, the more subtle misalignment in setting the light-receiving element will have a greater effect on the collimation. The property becomes extremely poor. Therefore, in the present invention, instead of using a light receiving element that matches the field of view, a light receiving element having a field of view wider than that field of view is adopted in order to secure a desired desired field of view, Be positively blocked at the partition. As a result, even if a slight displacement occurs during the setting of the light receiving element, the restriction of the fixed field of view by the partition can be easily made, the field of view can be reliably narrowed by the partition, and the field of view can be narrowed. As the influence of the "vertical movement" of the paper sheet can be reduced, an inexpensive paper sheet detection sensor that does not use a rod lens is realized.

It is preferable that the light receiving element is arranged toward the partition so that the light receiving center line of the light receiving element is oblique to the wall surface of the partition. In this manner, the light receiving center line of the light receiving element is inclined with respect to the wall surface of the partition,
When the light receiving element is set in the housing, the light receiving surface in the light receiving element is inclined so as not to be parallel to the paper sheet. This weakens the light receiving sensitivity of the light receiving element. In other words, such an arrangement of the light receiving elements limits the light receiving sensitivity inherent to the light receiving elements. This is because if the light receiving sensitivity is high, the sheet is liable to be affected by the "up and down movement" of the sheet, and the amount of change in the light receiving energy of the light receiving element becomes large, which tends to cause a detection error. Therefore, this paper sheet detection sensor minimizes the influence of the vertical movement of the paper sheet with two restrictions, that is, the restriction of the field of view by the partition part and the restriction of the sensitivity by the oblique arrangement of the light receiving element. is there.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a paper sheet detection sensor according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing a paper sheet inspecting apparatus 1. The sheet inspecting apparatus 1 is to be inspected.
This is true / false discrimination of banknotes, which are examples of paper sheets, and more specifically, discrimination between color-copied counterfeit banknotes and regular banknotes. This color copy paper contains a large amount of fluorescent components, and the true / false determination is performed by paying attention to this point.

The paper sheet inspection device 1 includes upper and lower guide plates 2,
3 is a straight transport path 4 formed to be sandwiched by
In the middle of the transport path 4, transport rollers 5 and 6 are arranged, and the transport rollers 5 and 6
To the discharge side. A bill recognition device 8 for identifying a denomination is disposed in the middle of the transport path 4.

Although not shown, the bill (sheets) recognition device 8 has a structure in which the surface of 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 in a state where it is difficult to determine the authenticity of the bill 7 only by the image recognition.

Therefore, a fluorescence detection sensor 10 which is an example of a paper sheet detection sensor is disposed upstream of the bill recognition device 8. As shown in FIGS. 2 and 3, the fluorescence detection sensor 10 has a partition 30 that divides the internal space of the housing 11 in the vertical direction.
And the light receiving element 16 are divided. An ultraviolet LED (light emitting element) for irradiating light toward the transport path 4 of the bill 7 is provided in one space formed by the partition part 30 of the housing 11.
12 are accommodated, and the ultraviolet LED 12
It is fixed to the housing 11 via a.

The LED 12 used here is an ultraviolet lamp containing a visible light component. And L as a light source
The reason for employing the ED 12 is that even if the housing 11 is small, there is a merit that the housing space is small, the variation in luminance is small, and the light fluctuation over time is small. Is optimal.

A rectangular window 13 is provided on the lower surface of the housing 11, and the window 13 is covered with a dustproof glass plate 14 with an adhesive or the like.
Is fitted. On the light receiving element 12 side,
An ultraviolet transmission filter 15 is attached to the upper surface (inner surface) of the dustproof glass plate 14. Therefore, UV LED
When the light emitted from the light source 12 passes through the ultraviolet transmission filter 15, an ultraviolet component (for example, 300 to 400) is emitted.
nm) is emitted to the transport path 4 via the dustproof glass plate 14. Then, the dust-proof glass plate 1 passes through the transport path 4.
The bill 7 sent to just below 4 is illuminated by this ultraviolet light.

A light receiving element (photo sensor) 16 for detecting fluorescence emitted from the surface of the banknote 7 is accommodated in the other space formed by the partition 30 of the housing 11. Is fixed to the housing 11 via the lead portion 16a. Therefore, when the banknote 7 illuminated by the ultraviolet rays contains a fluorescent component,
The excited fluorescence is emitted from the banknote 7 and is
6 detects. That is, when the counterfeit banknote 7 that has been color-copied is sent into the transport path 4, a large amount of fluorescent components are contained in the color copy sheet, so that a large amount of fluorescent light is detected by the light receiving element 16. On the other hand, a legitimate banknote hardly contains a fluorescent component, and the sensor 1
The voltage change of No. 6 is extremely small.

On the light receiving element 16 side, an ultraviolet cut filter 17 is attached to the upper surface (inner surface) of the dustproof glass plate 14. The reason for employing such an ultraviolet cut filter 17 is that light reflected on the surface of the banknote 7 contains an ultraviolet component, and since this ultraviolet component has a high energy characteristic, erroneous detection is avoided. This is because it is necessary to remove the ultraviolet component in order to make it work.

Here, as shown in FIG.
The one having a wide field of view (for example, one having a viewing angle α of 110 degrees) is used. This is because if a light-receiving element with a narrow field of view is used, light can be received in a spot-like manner and the light-receiving efficiency can be increased. This is because the subtle displacement greatly affects the collimation, and it is difficult to adjust the collimation when a light receiving element having a narrow field of view is used, which significantly deteriorates the assembling workability. Therefore, a light receiving element 16 having a large viewing angle α is employed.

Here, the banknote 7 is moved at high speed in the transport path 4 by the transport rollers 5 and 6, whereby the banknote 7 is moved in the transport path 4 while causing up and down movements like waves. Moving. Such "up and down"
Since the variation of the received light energy is increased to cause a detection error, it is necessary to reduce the influence as much as possible. For that purpose, it is preferable to reduce the field of view of the light receiving element 16 as much as possible. However, as described above, the light receiving element 16 having a wide field of view is used.

Therefore, a desired narrow viewing angle β (for example, 30
In order to create the degree of light, a partition 30 that divides the light emitting element 12 and the light receiving element 16 is used. Reach limits. Thus, the light receiving element 16 having a wide field of view is adopted, and the field of view is
As a result of positively blocking by the wall surface 30a of the partition part 30,
Even if a slight displacement occurs during the setting of the light receiving element 16, the restriction of the fixed field of view by the partition 30 can be easily made, and the field of view can be reliably narrowed by the partition 30. In addition, the influence of the "vertical movement" of the bill 7 is reduced. In addition, in order to narrow the field of view, it is preferable that the light receiving element 16 be brought as close as possible to the wall surface of the partition 30.

Further, the light receiving element 16 has a light receiving center line P
Is set in the housing 11 so as to be inclined with respect to the wall surface of the partition 30. That is, the light receiving element 16
Is an angle θ (eg, 60 °) with respect to the wall surface of the
Degree). As a result, the light receiving surface 16a in the light receiving element 16 is inclined so as not to be parallel to the banknote 7, and the light receiving sensitivity on the light receiving surface 16a is intentionally weakened.

With such an arrangement of the light receiving element 16,
The light receiving sensitivity of the light receiving element 16 is limited. This is because if the light receiving sensitivity is high, the sheet is liable to be affected by the "up and down movement" of the sheet, and the amount of change in the light receiving energy of the light receiving element becomes too large, which tends to cause a detection error. Thus, the above-described fluorescence detection sensor 10
The banknote 7 has two restrictions, that is, the restriction on the field of view by the partition unit 30 and the restriction on the sensitivity due to the oblique arrangement of the light receiving elements.
The effect of the vertical movement is minimized.

The paper sheet detection sensor according to the present invention is not limited to the above-described embodiment. For example, the paper sheet detection sensor is not limited to the detection of fluorescence, but may be a sensor for detecting light of another wavelength. Further, the paper sheet is not limited to a bill, but may be a card, a securities, or the like.

[0023]

The paper sheet detection sensor according to the present invention is configured as described above, and therefore has the following effects.
That is, in the middle of transporting the paper sheet, the paper sheet is illuminated with light, and the paper sheet detection sensor that receives light from the surface of the paper sheet is accommodated in the housing, and the paper sheet is transported. A light-emitting element that irradiates light toward the path, and housed in a housing,
A light-receiving element for receiving light from the surface of the paper sheet, and a partition for separating the light-receiving element and the light-emitting element are provided, and the light-receiving element is arranged toward the partition, and a viewing area of the light-receiving element is partitioned. The cost can be reduced by reducing the number of lens components.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view illustrating an embodiment of a paper sheet detection sensor according to the present invention.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is an enlarged sectional view of a main part of FIG. 2;

[Explanation of symbols]

Reference numeral 4: conveyance path, 7: bills (sheets), 10: fluorescence detection sensor (sheet detection sensor), 11: housing, 12: LED
(Light emitting element), 16 ... Light receiving element, 30 ... Partition part, 30
a: wall surface of the partition, P: light receiving center line.

Claims (2)

[Claims] 1. A sheet detecting sensor for irradiating light to the sheet and receiving light from the surface of the sheet while the sheet is being conveyed, wherein the sheet is housed in a housing. A light emitting element that irradiates light toward the transport path of the paper sheet; a light receiving element that is housed in the housing and receives light from the surface of the paper sheet; and the light receiving element and the light emitting element And a partition section for dividing the light receiving element, wherein the light receiving element is arranged toward the partition section, and a field of view of the light receiving element is limited by the partition section. 2. The light receiving element is arranged toward the partition so that a light receiving center line of the light receiving element is oblique to a wall surface of the partition.
The paper sheet detection sensor as described in the above.