Counterfeit Currency Detector

Abstract

The apparatus disclosed detects counterfeit U.S. paper currency in a manner which is simple, quick, and requires little or not skill. Almost all official U.S. paper currency does not exhibit a chromamorphic response other than that naturally attributable to the cotton or linen stock. Almost all counterfeit currency will exhibit a definite chromamorphic response in the blue range when activated by properly filtered ultraviolet light. Any suspected counterfeits are further subjected to a test for determining the magnetic characteristics of the ink. Genuine U.S. paper currency for the last 25 years uses black ink which incorporates a magnetic pigment.

Description

The present invention is directed to a counterfeit currency detector so as to provide a quick and simple means for detecting counterfeit U.S. paper currency. The invention requires little or no skill to use. The invention may be used to validate genuine U.S. paper currency.

It has been ascertained through tests and investigations that almost all genuine paper currency made by the U.S. Mint is made from paper which does not include any fluorescent dyes, optical bleaches, or pigments. When genuine paper currency is illuminated by ultraviolet light from approximately 2,500 to approximately 4,000 angstrom units, the currency generally does not exhibit a chromamorphic response other than that naturally attributable to the cotton or linen stock. In recent years, even the U.S. Mint has had difficulty in obtaining rag stock completely free from fibers containing optical bleaches or other fluorescent materials.

Almost all counterfeit currency printed in the past 15 years has been made from rag stock which has a definite chromamorphic response in the blue range when activated by properly filtered ultraviolet light. The present invention recognizes this feature and the invention is predicated thereon.

Occasionally, genuine U.S. paper currency contains isolated fibers which exhibit a chromamorphic response. This is particularly, but not exclusively, true with respect to 10 and 20 dollar bills from the 1963 series. The response exhibited by such currency can be distinguished, with some experience, from counterfeit currency in which the entire unprinted paper surface exhibits a uniform, unbroken fluorescence in blue range, varying in brightness with the amount of optical bleach in the paper stock.

Much counterfeit paper currency, although containing optical bleach, may have a low level of chromamorphic response which is indistinguishable, or nearly so, from legal paper currency, when viewed in an area of high ambient visible light. Besides the fact that on occasion genuine paper currency will exhibit a chromamorphic response which might confuse someone other than a viewer who is well trained or instructed, there are other explanations for possible confusion. For example, genuine currency is often left in wearing apparel which is washed in a bath containing a high amount of optical bleach. Some of the bleach is absorbed by the paper stock and tends to lead one to suspect it as being counterfeit. After viewing tens of thousands of bills in banks, only two such bills have come to our attention.

Hence, after considerable experimentation, it has been ascertained that there is another characteristic of genuine paper currency which will facilitate further tests in confirmation of counterfeit currency. It has been ascertained that the black ink used to print the intaglio impression of genuine paper currency has magnetic characteristics which are detectable and will exhibit the specific reaction to a magnetic field. It is believed that the incorporation of magnetic pigment in the black ink has been a specification for genuine paper currency since 1941. The present invention contemplates subjecting any suspected counterfeits to a magnetic field and the lack of any response will be confirmation that the particular paper currency is counterfeit.

An important byproduct of the present invention is the education of the public with respect to the nature of counterfeit currency and to help them recognize genuine currency. The present invention may be used by the general public, banking institutions, institutions which lend money or handle large amounts of money, etc. The invention may be supplied with specimens which indicate the reaction to be obtained with genuine currency and the reaction to be obtained with counterfeits. Such specimens may exaggerate the unclear, indistinct and broken lines in counterfeits as well as the lifelike appearance of portraits in genuine paper currency. Often the red and blue threads in the paper of genuine currency are simulated in counterfeits by printing red and blue lines on the paper.

It is an object of the present invention to provide novel apparatus for detecting counterfeit paper currency and/or confirming the genuineness of U.S. paper currency.

It is another object of the present invention to provide apparatus for detecting counterfeit paper currency in a manner which is simple, quick, and requires little or no experience.

It is another object of the present invention to detect counterfeit currency and/or confirm the genuineness of paper currency by detecting the presence or absence of a chromamorphic response when the currency is subjected to properly filtered ultraviolet light in the range from approximately 2,500 to 4,000 angstrom units.

It is another object of the present invention to provide novel apparatus for confirming the genuineness or counterfeit nature of paper currency in response to the presence or absence of a reaction when the currency is subjected to a magnetic field.

Other objects will appear hereinafter.

For the purpose of illustrating the invention, there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

FIG. 1 is a perspective view of apparatus in accordance with the present invention.

FIG. 2 is a perspective view of another embodiment of the present invention.

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

FIG. 4 is a sectional view taken along the line 4--4 in FIG. 3.

FIG. 5 is a diagrammatic circuit diagram for the embodiment of FIGS. 2-4.

Referring to the drawing in detail, wherein like numerals indicate like elements, there is shown in FIG. 1 apparatus in the form of a counterfeit currency detector designated generally as 10. The detector 10 includes a housing designated generally as 12. The housing 12 may assume a wide variety of shapes and configurations. Within the housing 12, there is provided one or more light sources 16. In FIG. 1, two such light sources are shown.

The light sources 16 are long-wave ultraviolet light bulbs with an integral filter or exterior filter to absorb most visible light and transmit the desired ultraviolet rays. Filter 18 has a light blue color which permits the viewing of the light blue or bluish-white chromamorphic response of the counterfeit paper currency under ultraviolet light while at the same time reducing the visible ambient light in the viewing area permitting the unit be used in areas that are well lit.

While the suspected currency 24 is being subjected to the ultraviolet light, it is below filter 18. The housing 12 is provided with an opening 19 to facilitate positioning of the currency below filter 18 in a position so that the currency is exposed to the ultraviolet light of sources 16. If desired, a cover may be provided on the housing 12 overlying the filter 18. Such cover would reduce any effect of the visible ambient light. If desired, a completely enclosed shadow box or raised headpiece may be provided for viewing when the actor so desires.

The light sources 16 are coupled to a source of potential by way of the cord 20 and the on-off switch 22. Suitable ballast, not shown, is provided in housing 12 for the light sources 16. In any convenient location such as on the upper surface of housing 12, there is provided a recess within which paper currency 24 may be located for testing the magnetic properties of the black ink on the currency. The recess for the currency includes a member such as a scan head against which the currency will be supported in good intimate contact therewith. A magnet and the scan head are supported by member 30. Member 30 is mounted for sliding movement within the recess on the top wall of the housing 12 in a manner so as to overlie the currency 24.

In genuine paper currency, when the magnet is passed over the magnetizable pigments in the black ink, and the ink containing magnetic pigment is magnetized, a changing current flows through the scan head. When the scan head is passed over the magnetized ink, the changing current will pulse a switch control member coupled to a power supply and generate a signal. The signal can be a visual light 36 or an audible signal. Paper currency which does not induce the changing current when processed as shown is counterfeit.

The power supply may be connected to the light 36 and switch 22 by way of the electric cord 20. An indicator light 38 may be provided on the housing 12 to indicate that the apparatus 10 is connected to the power supply. Alternatively, the power supply may be a battery contained within the housing 12.

The apparatus 10 is utilized in the following manner.

Currency suspected to be counterfeit as well as genuine currency may be subjected to the ultraviolet light from light sources 16 and filtered by filter 18. If there is no chromamorphic response, the currency may be considered genuine. If any of the dies, bleaches or pigments on the currency exhibit a chromamorphic response, such as by fluorescing, the extent of the response should be noted. If the chromamorphic response is uniform and unbroken due to the optical bleach in the paper stock, the currency is counterfeit. If the chromamorphic response is sporadic and limited to specific fibers in the paper stock, the currency is probably genuine. However, since it is possible that some counterfeit currency is printed on paper with no chromamorphic response, if further observation of the printing indicates a questionable bill it should be subjected to the magnetic scan test for further verification.

The genuineness of currency may be confirmed by then placing the currency 24 in good contact with the pickup head. The major portion of the currency may be supported by a nonmagnetic plate 25. Thereafter, the magnet 28 is moved across the currency to ascertain whether or not there is any flux induced in the scan head. The magnetic pigment in genuine currency will induce a flux in the pickup head which in turn will cause the light 36 to light up for a short period of time such as 5 to 10 seconds. The automatic terminating of the light may be controlled by any conventional time delay or switch control means.

It will be appreciated that the individual bills of paper currency need not be viewed one at a time. That is, the bills may be held in a stack in the ultraviolet light-viewing area, underneath the filter 18 and then riffled while observing whether or not there is any chromamorphic response in the stack. It will be appreciated that the scan head is only illustrative of many devices which may be utilized to detect the presence of magnetic material in the pigment of the black ink on genuine currency. A magnetometer-type head, an eddy-current detector, etc. may be used in place of the scan head.

In FIGS. 2-4, there is illustrated another embodiment of the present invention designated generally as 10'. The embodiment 10' is identical with the embodiment 10 except as will be made clear hereinafter. Hence, corresponding primed numerals are provided for corresponding structure.

In the detector 10' , the light sources 16' the filter 18' , and the indicator 36' are supported by a cover 42. Cover 42 is hinged to housing 12' at pin 44. The cover 42 may be raised so as to provide sufficient space 46 below the filter 18' to accommodate a stack of bills and a person's hands. This will greatly facilitate riffling the stack of paper currency as described above.

In the detector 10' , the magnetic scanning is facilitated by means supported on the housing 12' below the elevation of the light sources 16'. As shown more clearly in FIGS. 3 and 4, this means for magnetically scanning the bills includes a platen 48 hinged to the housing 12'. The platen 48 includes a layer of shielding material 50 for keeping out stray magnetic fields. The magnetic shielding 50 may be a layer of Mu metal or equivalent material. Attached to the lower surface of the magnetic shielding 50, there is provided a cushion 52 such as a layer of rubber or foam plastic.

The paper currency 24' is positioned below the cushion 52 and is supported by a nonmagnetic platen 54. A magnet 28' is provided below platen 54 adjacent to a variable reluctance scan head 56.

As shown more clearly in FIG. 5, the scan head 56 is connected to a power supply 58. Scan head 56 is connected to the indicator 36' by way of an amplifier 60, discriminating circuit 62 and latch circuit 64. Per se, the elements 56-64 are conventional elements, the details of which are well known to those skilled in the art. Hence, further description of the same is not deemed necessary.

In connection with each of the embodiments of the present invention, the visual and magnetic-scanning tests may be separately or sequentially performed. If desired, the structure described above for performing the visual tests for chromamorphic response as well as the magnetic-scanning test may be provided in separate housings. Those skilled in the art will recognize that the variable reluctance scan head 56 detects the presence or absence of magnetic particles by the change in coupling of the coils in the head. The various elements of the circuitry may be disposed within housing 12 in the area designated 66. The ballast 69 is preferably supported by the cover 42 for movement therewith.

Detection of counterfeits or confirmation of genuineness is accomplished in a manner which is simple and quick by personnel having little or no experience. It will be apparent that the chromamorphic response may be detected mechanically or electrically by utilizing a photocell responsive to fluorescence. The photocell may trigger a circuit to indicate an audible signal, a visual signal, or some other signal for indicating the presence of counterfeit or suspected counterfeit paper currency. As used herein, chromamorphic response means color change.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof

Claims

It is claimed:

1. Apparatus for use in detecting counterfeit paper currency under conditions of high ambient light comprising a housing containing at least one source of ultraviolet light which will produce a chromamorphic response on paper currency adjacent thereto when the paper currency contains fluorescent dyes, pigments, or optical bleaches which fluoresce, a transparent filter supported adjacent said source of light, said filter having a light blue color so that said response can be observed under said conditions of high ambient light, said housing having an opening so that the currency may be observed while it is subjected to said source of light, and means for subjecting paper currency which exhibits a chromamorphic response to a magnetic field, said means including a signal responsive to circuitry which detects the presence of magnetizable material in pigment on the currency.

2. Apparatus in accordance with claim 1 wherein said means includes at least one magnet aligned with at least one scan head positioned so that paper currency may be located adjacent thereto while subjected to the magnetic field.

3. Apparatus in accordance with claim 1 wherein said means includes a variable reluctance scan head.

4. Apparatus in accordance with claim 1 wherein said signal is a visible signal.

5. Apparatus for detecting counterfeit paper currency under conditions of high ambient light comprising a housing containing at least one source of ultraviolet light which will produce a chromamorphic response on paper currency adjacent thereto when the paper currency contains dyes, pigments, or optical bleaches which fluoresce, said housing having a surface for supporting currency while being subjected to said light source, a transparent filter between said surface and said source of light, said filter having a light blue color so that said response can be observed under said conditions of high ambient light, said housing having a nonmagnetic support surface against which the paper currency can be positioned, means for generating a magnetic field adjacent said nonmagnetic surface, and an indicator coupled to said means for indicating the presence of magnetic particles on the paper currency when relative movement occurs between the paper currency and said magnetic-field-generating means.

6. Apparatus in accordance with claim 5 wherein said means is a variable reluctance scan head, and a magnetic shield spaced from and adjacent said nonmagnetic support surface so that the paper currency may be disposed therebetween.