Patent Publication Number: US-6714288-B2

Title: Counterfeit detection apparatus

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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     MICROFICHE APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the detection of security features on monetary documents and the like. The US Federal Government has taken steps in recent years to combat counterfeiting of paper currency. Other monetary issuing agencies throughout the world have taken like steps. Additionally, banking organizations have added security features to other documents such as checks to impede forgery. 
     2. The Prior Art 
     The advent of inexpensive computer and color printing and copying systems has made counterfeiting a much easier task than heretofore possible. As such, the US Government and other monetary issuing agencies have added a number of very difficult to duplicate features to the paper currency. The list below is particular to the US $10 bill but is indicative of the remainder of commonly circulated United States currencies. 
     1. Federal Reserve Indicators—A new universal seal represents the entire Federal Reserve System. A letter and number beneath the left serial number identify the issuing Federal Reserve Bank. 
     2. Portrait—The enlarged portrait of the first Secretary of the Treasury, Alexander Hamilton is easier to recognize, while the added detail is harder to duplicate. The portrait is now off-center, providing room for a watermark and reducing wear and tear on the portrait. 
     3. Security Thread—A polymer thread embedded vertically in the paper to the right of the portrait indicates the $10 denomination. The words “USA TEN” and a flag can be seen from both sides of the notes when held up to a bright light. The number “10” appears in the star field of the flag. Additionally, this thread glows orange when held under an ultraviolet light. 
     4. Watermark—A watermark based on the same artwork as the portrait is visible from both sides when held up to a light. 
     5. Color-Shifting Ink—The number in the lower right corner on the front of the note looks green when viewed straight on, but appears black when viewed at an angle. 
     6. Serial Numbers—An additional letter is added to the serial number. The unique combination of eleven numbers and letters appears twice on the front of the note. 
     7. Low-Vision Feature—The large numeral on the back of the $10 note is easy to read. Also, a machine-readable feature has been incorporated for the blind. It will facilitate development of convenient scanning devices that could identify the note as a $10. 
     8. Fine Line Printing Patterns—The fine lines printed behind both the portrait and the U.S. Treasury Building are difficult to replicate. 
     9. Microprinting—Because they&#39;re so small, microprinted words are hard to replicate. On the front of the note, “TEN” is continually repeated in the numeral in the lower left-hand corner, and “The United States of America” is repeated just above Hamilton&#39;s name. 
     There are means such as light tables, ultraviolet lamps, and illuminated magnifiers to individually or in some cases in combination to examine these features, but none provide an ability in a compact low cost device to examine a sufficient number to be certain of a bills validity. 
     U.S. Pat. No. 5,444,263, Instrument For The Visual Recognition Of Authenticity Features In Banknotes And Security Documents, invented by Wolfgang R. Mastnak, hereinafter referred to as the Mastnak patent, teaches some of the concepts of the present invention but defines the optics as a cylindrical lens which is incapable of multidirectional magnification of the image. As such the Mastnak invention cannot adequately magnify the microprinting for recognition as it is unidirectional in its magnification. Secondly the method of illumination is also flawed as both the back and front illumination are caused by end illumination the lens and the diffuser. There is no mention of a mirror, prism, or other optical means of direction other than scattered light toward the lens. Likewise, end illumination of the lens has equal if not a more severe flaw in that the fingerlike or cylindrical lens acts as a light pipe and directs the photons toward the lens end distal to the lamp. Only minor scattering of light illuminates the currency in both cases. Mastnak recognizes the flaw in the illumination intensity by tying to enhance the illumination through edge lighting of both the cylindrical lens and diffuser. Again, the efficacy in illuminating the currency in this manner without benefit of directive optics is likewise flawed. Mastnak&#39;s substitution of an ultraviolet lamp for the broadband visual spectrum lamp is similarly but more so flawed. Ultraviolet excited fluorescence visibility is very difficult to view in room light without having a shroud to limit the effects of ambient light. It is doubtfil that enough ultraviolet light will reach the phosphors in the thread to adequately fluoresce the thread with this optical arrangement. 
     The present invention resolves these limitations by providing a device with directed light sources to properly illuminate the currency, an omni-directional lens to magnify the microprinting and fine features for cognitive viewing and other novel features to enhance utility for viewing watermarks and color shifting inks. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a device to omni-directionally magnify the document of interest sufficiently to view the microprinting, and print quality. Another object is to provide a device that can back illuminate the bill for viewing the security thread and watermark and other imbedded features or those having partial aligned images on both the front and rear surfaces. Yet another object is to provide a front illuminating source that can be used to detect and validate the color shifting ink. A further object is to provide ultraviolet illumination to excite the phosphorescence of the security thread. An additional object is to provide a light shield to reduce the amount of room light interference at the lens and improve the brightness and contrast of the image. 
     The present invention provides a means for positioning a document at a distance from a magnifying lens to create a magnified in focus image while providing a light source within the visible light spectrum to rear illuminate the paper currency. It has a magnifying lens that is useful for enlarging the microprinting located at various locations such as around the face and within the denominational numeral on US paper currency. The microprinting can be seen with either front or rear illumination on the front surface of the currency, while rear illumination is needed to view the polyester thread and the watermark in US currency and alignment features within some non US denominations. The thread has printing which can be seen more easily when magnified, especially the denomination printed in the star field. 
     Additional features may be added to the basic invention such as an ultraviolet light source in the uvA range to facilitate determination of the fluorescent color of the polyester thread. A lamp emitting at approximately 370 nm is useful for this purpose and is easily filtered to prevent eye damage. UvB and uvc will accomplish fluorescence but are also more harmful and not suggested for this application. In US currency, the thread in the 5-dollar bill glows blue, in the 10-dollar bill it glows orange, in the 20-dollar bill it glows green, in the 50-dollar bill it glows yellow, while in the 100-dollar bill it glows red. Said ultraviolet lamp may be placed in front of or to the rear of the currency. It might additionally be useful to add an ultraviolet filter between the lens and the ultraviolet source to shield the user from ultraviolet light. Furthermore, a diffuser may be advantageously placed between the light source and the currency to make the illumination more uniform. 
     In a further embodiment of the present invention, a mirror is placed between the lens and the currency at an angle below the lower edge of the currency or above the upper edge of the currency. Said mirror is useful for reflecting light onto the front face of the currency to view the color changing ink. Said color changing ink appears black when rear illuminated and a reflective green when front illuminated. A further embodiment replaces the mirror with a second light source to illuminate the front surface of the currency. 
     When viewing the watermark it may be useful to move the magnifying lens out of the way to view the watermark unmagnified. 
     Other objects of the present invention will become apparent to those skilled in the art in light of the following drawings and detailed description of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a fuller understanding of the nature and object of the present invention, reference is made to the accompanying drawings, wherein: 
     FIG. 1 a  shows the location of security features of interest on the obverse side of a US $10 bill; 
     FIG. 1 b  shows the location of security features of interest on the reverse side of a US $10 bill; 
     FIG. 2 shows an optical diagram of basic invention; 
     FIG. 3 shows an additional optical diagram showing a front illumination mirror; 
     FIG. 4 shows an additional optical diagram showing an ultraviolet front light source; 
     FIG. 5 shows a cross-sectional view of one embodiment of the invention; 
     FIG. 6 shows a cross-sectional view of another embodiment of the invention with reflective mirror; 
     FIG. 7 shows a cross-sectional view of a further embodiment of the invention with additional light sources; and 
     FIG. 8 shows a cross-sectional view of one embodiment of the invention with a breakaway lens; 
    
    
     DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS AND THE BEST MODE 
     The illustrated FIGS. 1 through 8 are herein referenced to depict the various features of the present invention. FIGS. 1 a  and  1   b  depicts a facsimile of the US $10 bill  38  as a reference to the zones of interest for validating the authenticity of a US $10 dollar bill. It will be recognized by those skilled in the art that other currency denominations of the United States as well as currency with security features of other nations can be validated in the same manner. It will also be recognized that other documents such as personal and corporate checks are presently utilizing microprinting, watermarks, and other security measures that the present invention will be useful to detect and view. 
     Item  40  has microprinting within the border of the numeral  10  and  44  microprinting around the lower rim of the portrait  46 . Said microprinting is approximately 0.2 millimeters or 0.008 inches high. It will be recognized by those skilled in the art that magnification of this feature is essential for recognition. Fine line work  47  is located behind the portrait  46  on the obverse and behind the treasury building on the reverse. Item  42  is the representative area wherein an embedded printed thread is located. The location may vary on the different denominations. Item  45  is the numeral denomination printed in color changing ink. 
     FIG. 2 shows a diagram of the basic implementation of the present invention. The eye  9  represents the viewer looking at the magnified image. The lens  10  being a magnifying lens or lens system with a magnification greater than or equal to 2, positioned so that the surface of the document  18  is positioned to create an in focus image. A magnification of 10× is preferred. The room-light minimizing shroud  5  surrounds the lens to provide a measure of isolation from the ambient light. The remainder of the present invention includes a light source  25  with a luminous output in the visible light spectrum, a reflector  28  for focusing the light source on the back of the document  18 , a power source  20  herein shown as a battery, and a switch  30 . One terminal of said power source  20  is connected to a first terminal of said light source  25  while the second terminal of said power source  20  is connected to a first terminal  36  of said switch  30 . The second terminal  37  of said switch is connected to the second terminal of said light source  25 . It will be recognized by those skilled in the art that the light source  25  is not limited to incandescent lamps but might be an led of various spectral emissions, a florescent lamp, an electroluminescent lamp, an Ultraviolet gas discharge lamp, or an Ultraviolet led. Other types of lighting are by definition not eliminated. It will also be recognized by those skilled in the art that various power sources are possible including batteries, electronically controlled power sources and alternating current, AC. 
     FIG. 3 shows a diagram of another implementation of the present invention. The eye  9  represents the viewer looking at the magnified image. The lens  10  being a magnifying lens or lens system with a magnification greater than or equal to 2, positioned so that the surface of the document  18  is positioned to create an in focus image. A magnification of 10× is preferred. The room-light minimizing shroud  5  surrounds the lens to provide a measure of isolation from the ambient light and has a moveable mirror reflector  19  located between said document  18  and said lens  10 . Said moveable mirror reflector  19  providing a means for reflecting a portion of said light provided by said light source upon the obverse surface of said document  18 . Said moveable mirror reflector  19  may be positioned to reflect light upon the color shifting ink or to shut off transmission of light to the obverse surface. The remainder of the present invention includes a light source  25  with a luminous output in the visible light spectrum, a reflector  28  for focusing the light source on the back of the document  18 , a power source  20  herein shown as a battery, and a switch  30 . One terminal of said power source  20  is connected to a first terminal of said light source  25  while the second terminal of said power source  20  is connected to a first terminal  36  of said switch  30 . The second terminal  37  of said switch is connected to the second terminal of said light source  25 . 
     FIG. 4 shows a diagram of a further implementation of the present invention. The eye  9  represents the viewer looking at the magnified image. The lens  10  being a magnifying lens or lens system with a magnification greater than or equal to 2, positioned so that the surface of the document  18  is positioned to create an in focus image. A magnification of 10× is preferred. The room-light minimizing shroud  5  surrounds the lens to provide a measure of isolation from the ambient light and has a second light source  27  located between said document  18  and said lens  10 . Said second light source  27  providing a means for illuminating said obverse surface of said document  18 . Said second light source  27  is positioned to illuminate the color shifting ink or may be shut off to allow only back lighting from light source  23 . Second light source  27  may be a visible or ultraviolet source. In fact both types of light source may be available in the same embodiment. Additionally a mirror reflector may be positioned as in FIG. 3 behind said second light source  27  being attached to said moveable mirror reflector  19  and serves to reflect the visible light of light source  25  when said second light source  27  is Ultraviolet and is off or the ultraviolet source when the visible light source  25  is off. Said moveable mirror reflector  19  may be positioned to reflect light upon the color shifting ink or to shut of transmission of light to the obverse surface. The remainder of the present invention includes a light source  25  with a luminous output in the visible light spectrum, a reflector  28  for focusing the light source on the back of the document  18 , a power source  20  herein shown as a battery, and a switch  30 . One terminal of said power source  20  is connected to a first terminal of said light source  25  while the second terminal of said power source  20  is connected to a first terminal  36  of said switch  30 . The second terminal  37  of said switch is connected to the second terminal of said light source  25 . 
     FIG. 5 presents the preferred embodiment of the present invention. It includes an omni-directional magnifying lens or lens system  10 . Said lens system may be as simple as a single element lens having a spherical like first surface  10   a  and a flat second surface  10   b , a single or multi-element aspheric lens set, or a zoom lens having a minimum magnification of 2. A magnification of 10× is preferred. A room-light minimizing shroud  5  surrounds said lens  10 . Said shroud  5  having a document positioning slit  15  for positioning document  18  in focus with said lens  10 . On the distal side of said document positioning slit  15  is a lamp reflector  28 , housing a light source  25  located in a power source and lamp assembly housing  35 . Said power source and lamp assembly housing  35  further containing a set of contacts for connecting a first terminal  36  of said power source  20  to a first terminal  32  of said light source  25  while the second terminal  37  of said power source  20  is connected to a first terminal of said switch  30 . The second terminal of said switch  30  is connected to the second terminal  33  of said light source  25 . Said power source and lamp assembly housing  35  being fixably connected to said shroud  5 . 
     FIG. 6 presents a second embodiment of the present invention. It includes an omni-directional magnifying lens or lens system  10 . Said lens system may be as simple as a single element lens having a spherical like first surface  10   a  and a flat second surface  10   b , a single or multi-element aspheric lens set, or a zoom lens having a minimum magnification of 2. A magnification of 10× is preferred. A room-light minimizing shroud  5  surrounds said lens  10 . Said shroud  5  having a document positioning slit  15  for positioning document  18  in focus with said lens  10  and a moveable mirror reflector  19 . On the distal side of said document positioning slit  15  is a lamp reflector  28 , housing a light source  25  located in a power source and lamp assembly housing  35 . Said power source and lamp assembly housing  35  further containing a set of contacts for connecting a first terminal  36  of said power source  20  to a first terminal  32  of said light source  25  while the second terminal  37  of said power source  20  is connected to a first terminal of said switch  30 . The second terminal of said switch  30  is connected to the second terminal  33  of said light source  25 . Said power source and lamp assembly housing  35  being fixably connected to said shroud  5 . 
     FIG. 7 presents an additional embodiment of the present invention. It includes an omni-directional magnifying lens or lens system  10 . Said lens system may be as simple as a single element lens having a spherical like first surface  10   a  and a flat second surface  10   b , a single or multi-element aspheric lens set, or a zoom lens having a minimum magnification of 2. A magnification of 10× is preferred. A room-light minimizing shroud  5  surrounds said lens  10 . Said shroud  5  having a document positioning slit  15  for positioning document  18  in focus with said lens  10  and a moveable mirror reflector  19  mountably containing a front light source  27 . Said front light source  27  may be an Ultra violet gas discharge lamp powered by an inverter circuit or the like or by a DC power source if said ultraviolet light source is a UV-led. On the distal side of said document positioning slit  15  is a lamp reflector  28 , housing a light source  25  located in a power source and lamp assembly housing  35 . Said power source and lamp assembly housing  35  further containing a set of contacts for connecting a first terminal  36  of said power source  20  to a first terminal  32  of said light source  25  while the second terminal  37  of said power source  20  is connected to a first terminal of said switch  30 . The second terminal of said switch is connected to the second terminal  33  of said light source  25 . Said power source and lamp assembly housing  35  being fixably connected to said shroud  5 . 
     FIG. 8 presents a further embodiment of the present invention. It includes an omni-directional magnifying lens or lens system  10 . Said lens system may be as simple as a single element lens having a spherical like first surface  10   a  and a flat second surface  10   b , a single or multi-element aspheric lens set, or a zoom lens having a minimum magnification of 2. A magnification of 10× is preferred. A room-light minimizing shroud  5  surrounds said lens  10 . Said shroud  5  having a document positioning slit  15  for positioning document  18  in focus with said lens  10 . Said shroud  5  further having a hingeable joint for swinging said omni-directional magnifying lens or lens system  10  out of the way so that said document  18  is viewable without magnification when back illuminated by said light source  25 . Said configuration is useful for illuminating such features as watermarks and front and back split features without benefit of magnification. On the distal side of said document positioning slit  15  is a lamp reflector  28 , housing a light source  25  located in a power source and lamp assembly housing  35 . Said power source and lamp assembly housing  35  further containing a set of contacts for connecting a first terminal  36  of said power source  20  to a first terminal  32  of said light source  25  while the second terminal  37  of said power source  20  is connected to a first terminal of said switch  30 . The second terminal of said switch is connected to the second terminal  33  of said light source  25 . Said power source and lamp assembly housing  35  being fixably connected to said shroud  5 . Those skilled in the art will appreciate that various features of FIGS. 6 and 7 can be combined with FIG. 8 to get differing configurations. 
     As will be obvious to persons skilled in the art, various modifications, adaptations, and variations of the specific disclosure can be made without departing from the teaching of the invention.