JPS63148391A - Paper money discriminator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a bill validating device, and particularly to a device that uses a prism to disperse reflected light or transmitted light from a bill, and determines the authenticity or type of a bill based on the wavelength-specific intensity distribution of the dispersed light.

[Conventional technology]

Conventional banknote validators often employ methods based on the magnetic properties of banknotes. Currently, the technology for counterfeiting and altering this magnetic method is relatively advanced. Therefore, in order to counter this forgery and alteration technology, an identification device based on a new and more advanced method is expected. One of them is a method based on the color tone characteristics of banknotes. The main methods that have been proposed so far based on the color characteristics of banknotes are: - Method using color filters corresponding to the three primary colors of light - Method using light-emitting elements that mainly emit light in the three primary colors of light Method (2) will be explained with reference to FIG. The light from the light source 31 is reflected on the surface of the banknote 10,
Color filters 32A and 32B corresponding to three primary colors. After passing through 32C, the light receiving elements 33A, 33
B. 33C. Next, method (2) will be explained with reference to FIG. Here, colored light from light emitting elements 41A, 41B, and 4IC that emit mainly three primary colors is reflected on the surface of the banknote IO, and enters light receiving elements 43A, 43B, and 43C that can receive only colored light of each of the three primary colors. .

[Problems to be Solved by the Invention] As mentioned above, in the conventional technology, one thing that is common to the above-mentioned methods (1) and (2) is that the wavelength of light is separated only into those corresponding to the three primary colors. Another problem is that there are relatively large "variations" in the transmittance of color filters, the brightness of light emitting elements, the sensitivity of light receiving elements, etc. Furthermore, a particular drawback of the method (2) is that the wavelength characteristics of the color filter transmittance are not sharp. In other words, it is not the case that the transmittance is good only at certain wavelengths and the transmittance is extremely low at other wavelengths, but rather that the transmittance is almost uniform over a certain range of wavelengths, that is, the wavelength characteristics of the transmittance are sharp. (No, that is.) The other disadvantage peculiar to method (■) is that the colored light emitted by the light emitting element contains relatively many components other than those corresponding to the three primary colors.In other words, , the wavelength characteristics of the emission spectrum are not sharp.Therefore, there are the following problems.First, the wavelength is only separated into the three primary colors, so the wavelength characteristics of the banknotes are not sharp. be insufficient to detect tonal characteristics;
Second, due to the above-mentioned "dispersion" in each characteristic, it takes time and effort to manage, sort, and adjust components and elements, and even then, it is difficult to obtain sufficient results. Furthermore, as a problem specific to each method, each wavelength characteristic regarding the color filter transmittance (1) and the emission spectrum (2) is not sharp, which becomes an obstacle to accurately detecting the color tone characteristics of banknotes. The purpose of this invention is to solve the above problems of the conventional technology, highlight the wavelength characteristics, measure the intensity distribution of light reflected or transmitted from banknotes by wavelength, and based on this, It is an object of the present invention to provide a bill validating device that can make a judgment and can sufficiently deal with "variations" in the characteristics of each component or element.

[Means for Solving the Problems] In order to achieve the above object, the present invention takes the following configuration. (1) A light guide means that guides reflected light or transmitted light from a banknote into a light beam with a minute cross section, and (2) This light guide means □For example, by using an optical fiber or two pinholes □ provided at a distance. a prism that disperses the guided light beam based on its wavelength; (3) a light receiving element arranged in parallel at each position of the dispersed light by the prism, Determine authenticity or type. Note that the light beam guided by the light guide means may be made to correspond to a predetermined portion of the banknote, or may be made to correspond to the entire predetermined area of the banknote. [Operation] Since the structure is as described above, the operation of the present invention is as follows. ■Light reflected or transmitted from banknotes is dispersed by a prism, forming straight lines of colors arranged in order of wavelength, that is, a dispersion spectrum. (2) The intensity of each color of light is detected by light-receiving elements arranged in an array on the straight line of this light. (2) The overall state of the intensity distribution by wavelength of light can be known. ■The authenticity of banknotes can be determined from the characteristics of this wavelength-based intensity distribution. It is possible to determine the type. As an embodiment, the color tone characteristics of the banknote can be accurately grasped by determining the intensity distribution of each wavelength of light for each predetermined part of the banknote - a part □ having characteristics in terms of color tone. In another embodiment, the device configuration and measurement work can be simplified by knowing the average wavelength-specific light intensity distribution for the entire area of a banknote.

【Example】

First, the principle of this invention will be explained with reference to the principle diagram in FIG. After light reflected or transmitted from a banknote (not shown) passes through a guide path 7, it becomes a light beam 8 with a minute cross section. This luminous flux 8
is dispersed by the prism 2 to become dispersed light 9, which enters a light receiving element array 3 in which light receiving elements are arranged in a row at a location corresponding to the irradiation surface of this dispersed light 9. Since the dispersed light 9 creates a light spectrum based on the wavelength of the light, the intensity of each wavelength is detected by each light receiving element constituting the light receiving element array 3, and an overall intensity distribution of each wavelength is obtained. This wavelength-based intensity distribution represents the color tone characteristics of the corresponding location on the banknote, so if this location is appropriately selected, the authenticity or type of the banknote can be determined based on this. Note that the optical guide path 7 can be, for example, an optical fiber, or alternatively, it can be two pinholes placed at a certain distance. In the latter case, the straight line connecting the two pinholes becomes the optical path. An embodiment of the present invention will be described below with reference to FIG. Note that FIG. 2 is a perspective view of this embodiment, in which the intensity distribution according to wavelength is measured for a plurality of predetermined portions of a banknote. In FIG. 2, banknotes 10 are being conveyed in the direction of arrow P. A rod-shaped light source 15 illuminates the surface of the banknote 10 from above, and N optical fibers 11 are arranged in parallel in a direction perpendicular to the conveyance direction of the banknote 10. One end of the optical fiber 11 is close to and opposed to the surface of the banknote 10, and the other end is close to and opposed to the slope of each prism 12. To receive the light dispersed by each prism 12, a light-receiving element array 13 □ consisting of N light-receiving elements in the horizontal direction and M in the vertical direction is provided which are arranged in a plane. Since the configuration is as described above, the operation of this embodiment is as follows. ■The light reflected from each point on a predetermined straight line in the direction perpendicular to the conveying direction (P direction) of the banknote 10 passes through each optical fiber 11 that is close to and facing each other, and becomes a light beam with a minute cross section, and becomes a light beam with a minute cross section, incident on the slope of (2) Each of these light beams is dispersed by each prism 12 to form a straight line of colors arranged in the order of wavelength, that is, a dispersion spectrum, and each of these dispersion spectra is arranged horizontally at the same time. (2) Therefore, on each line of this dispersion spectrum, the intensity of each color of light is detected by the light receiving elements arranged in an array. (2) As a whole, the intensity distribution state of the reflected light from each point on the predetermined straight line of the banknote 10 by wavelength can be known. (2) Further, as the banknote 10 is conveyed, the intensity distribution of reflected light by wavelength can be similarly obtained for each point along other straight lines. The selection of a predetermined measurement point should be made on the basis of the point that most clearly represents the characteristics of the color tone, and it goes without saying that the number of measurement points should be the minimum necessary. (2) Therefore, it is possible to easily determine the authenticity of two types of banknotes from the characteristics of the many appropriate wavelength-specific intensity distributions obtained as described above. Note that "variations" in the sensitivity of each light receiving element constituting the light receiving element array 13 can be corrected by, for example, calculating the output of each light receiving element under a certain reference light source in advance and applying correction based on this output value. Bye. Moreover,
It can be automatically corrected by a computer. Next, a second embodiment will be described with reference to FIG. 3. The aim of this embodiment is to reduce the number of light-receiving elements as much as possible, simplify the measurement work, and shorten the time. In FIG. The entire surface is illuminated by a light source 25.The reflected light from the entire surface of the banknote 10 is collected at one end of the optical fiber 21 by a condensing lens 26.The light flux guided by this optical fiber 21 is 22, and are dispersed and incident on the light-receiving element array 23. In this case, the light-receiving element array 23 is simply arranged in a line in the vertical direction.As described above, this embodiment Here, the color tone characteristics of the banknote 10 are expressed averagely over the entire surface, and this is sufficient depending on the required accuracy of determination and the purpose or conditions of use of the banknote discrimination device to which this is applied.Furthermore, , the measurement range of the banknote may be a certain specific area instead of the entire surface of the banknote. In this embodiment, (1) the number of light-receiving element arrays and optical fibers is small, and the configuration is simple; Therefore, it has advantages such as being advantageous in terms of cost, □ data processing is simple due to the small number of measurement points for intensity distribution by wavelength, and judgment processing is particularly simple and short □. Effects of the Invention] As explained above, in this invention, the light reflected or transmitted from the banknote is dispersed by the prism, forming a straight line of colors arranged in the order of wavelength, that is, a dispersion spectrum; The intensity of each color of light is detected by the light-receiving elements arranged in an array; the overall state of the light intensity distribution by wavelength can be determined; based on the characteristics of this wavelength-specific intensity distribution, the authenticity of the banknote can be determined. It is possible to determine two types of counterfeits. Therefore, the present invention has the following superior effects compared to conventional techniques: (1) Determination is based on a relatively new method called color tone characteristics of banknotes. (2) By narrowing the pitch of parallel arrangement of photodetector arrays, wavelength resolution can be increased, which improves the accuracy of banknote identification. (3) It is possible to sufficiently deal with "variations" in the characteristics of each component.In other words, there is almost no need to manage or select the characteristics of each element, and adjustments can be easily made as follows. That is, the light receiving element output based on the reference light source is determined in advance, and correction, for example automatic correction by a computer, is applied based on this. (4) The device configuration is relatively simple, and the reliability and cost are sufficient for practical use. (5) According to the embodiment, since a large amount of data necessary for banknote determination is obtained, the determination accuracy is improved. (6) According to another embodiment, the number of constituent members and elements is reduced, resulting in cost reduction, data collection procedures are simplified, and determination time is shortened.

[Brief explanation of the drawing]

Fig. 1 is a principle diagram showing the present invention, Fig. 2 is a perspective view of a first embodiment according to the invention, Fig. 3 is a perspective view of the second embodiment, and Fig. 4 is a perspective view of a conventional example. Side View FIG. 5 is a side view of another conventional example. Symbol explanations 1.11, 21: Optical fiber, 2.12.22 Nibrism, 3.13.23: Light receiving element array, 7: Optical guide path, 8: Luminous flux, 9: Dispersed light, 10: Banknote, 15, 25
:light source. Figure 2 Figure 3 Figure 3A Figure 5

Claims (1)

[Scope of Claims] 1) A light guide means for guiding reflected light or transmitted light from a banknote into a light beam with a minute cross section, a prism that disperses the light flux guided by the light guide means based on its wavelength, and this prism. a light receiving element arranged in parallel at each position of the dispersed light, and determines the authenticity or type of the banknote based on the wavelength-specific intensity distribution of the dispersed light. 2) A bill validating device according to claim 1, wherein the light beam guided by the light guide means corresponds to a predetermined portion of the bill. 3) A bill validating device according to claim 1, wherein the light beam guided by the light guide means corresponds to the entire predetermined area of the bill. 4) A bill validating device according to any one of claims 1 to 3, wherein the light guide means is an optical fiber. 5) A banknote discrimination device according to any one of claims 1 to 3, wherein the light guide means is two pinholes provided at a distance. .