SCANNER WITH WAVEGUIDE FOR SCANNING PAPER CURRENCY

Abstract: A light-scanner (200) that includes a wave guide (230). The scanner (200) defines a scanning zone, and further includes a light-emitting diode (214), and a detector. The wave guide (230) is disposed between the light-emitting diode (214) and the scanning zone. The wave guide (230) defines a light-admitting aperture and a light-reflective surface. The light-admitting aperture and light-reflecting surface cooperate to direct light from the light-emitting diode toward the scanning zone, and to focus such light centrally along a path traveled by such light toward the detector.

Description: Scanner with Waveguide for Scanning Paper Currency The present invention, in general, is directed to scanners. More particularly, the present invention is directed to an apparatus and method for scanning paper currency for the purpose of verifying the authenticity as well as determining the value thereof. Conventional paper-currency scanning devices are, e.g., typically associated with vending machines that provide consumers with beverages and snacks as well as separate mechanisms located in, e.g., recreational areas having casino slot machines that accept paper currency and/or video arcades that provide coins in exchange for paper currency. Such scanning devices typically employ a light source to illuminate the currency as well as a detector system that picks-up features or characteristics from the currency. The United States government, e.g., has recently introduced an assortment of bills that include noticeably asymmetric indicia such as portraits of familiar individuals, and which incorporate other unique features and characteristics that make counterfeiting its paper currency more difficult than ever. Additionally, a number of other countries have paper currencies that may vary in color as well as dimension, depending upon valuation. As a result of such security measures, a number of conventional paper currency-scanning devices and systems further frequently incorporate at least one light source as well as an associated collimating lens for producing a beam of substantially parallel light rays that pass through and illuminate the paper currency from one side thereof. Typically located on the opposite side of the illuminated currency is an associated planar/convex lens for gathering scatter rays from the bill, and which thereafter provides the gathered scatter rays to an associated detector that is designed, in ideal situations, to be capable of verifying the authenticity as well as detecting the value of the scanned bills. Also, the convex lens is typically so spaced from a desired scanning plane (for the paper currency) such that the focal point of the lens ideally touches the scanning plane. Accordingly, in ideal situations, indicia and other characteristics incorporated into current paper currency for security reasons are capable of providing light passing through the scanned bill with information that is compared to certain stored information, for the purpose of verifying authenticity as well as value of the paper currency being scanned. However, movement of the paper currency above or below its desired scanning plane may take the bill out of the lens focal point. To both collimate and focus light on a point poses design constraints, especially in view of the fact that displacement of as little as one (1) millimeter away from a desired focusing position may move the focal point out of its associated desired viewing position. Moreover, paper currency that is torn, taped, discolored, very creased or wrinkled, or worn thin may further aggravate the problem. Further still, paper by its nature diffuses light. As a result, diffused light passing through a bill located in the desired scarining plane, which is thereafter focused, may fall short of the detector entirely, or the light rays passing through the convex lens may focus light from the scanned bill behind a desired detection zone, either of which is undesirable. Accordingly, when comparing information from a scanned bill to such calibration information, there can be a disparity between the bill and stored calibration information as well as non-compliance of certain wavelengths of light, for reasons mentioned above. Disparity between the scanned bill and the calibration information may be within design tolerance of many conventional currency-scanning devices, with the result that the scanned bill is accepted. Non-compliance of wavelengths, however, is another matter. To solve such problems, conventional currency-scanning devices may include, as the light sources thereof, certain light-emitting diode devices (or so- called "packages"), that are capable of providing light of multiple wavelengths. Conventional scanners may therefore incorporate a plurality of such state-of- the-art light-emitting diodes (LEDs), for the purpose of "solving" a perceived problem. In this regard, a single currently commercially-available LED package capable of operating from blue to infrared, when incorporated into the above- described conventional currency-scanning device, is able to provide the scarining device with a source of light having the characteristic wavelengths of 470, 505, 620, 730, 840 and 940 nanometers. Unfortunately, state-of-the-art paper currency-scanning devices, of current design, often incorporate twelve or more of the above-described LED packages, if such scanning devices are to verify currency authenticity and value, to meet their commercial purpose. For a number of reasons, it would therefore be desirable to reduce the number of presently available LED packages described above from twelve or more to as few as four. SUMMARY OF THE INVENTION The present invention is directed to a scanner apparatus that does not require a collimating lens. Instead, the scanner apparatus incorporates a waveguide. Moreover, the resulting design of the scanner apparatus of the invention has enabled reducing the number of light-emitting diode (LED) packages from twelve or more to four or less. The scanner apparatus of the invention is preferably used to scan paper currency for the purpose of verifying the authenticity as well as determining the value thereof. Also, when the scanner apparatus of the invention incorporates four such LED packages, each such LED package is preferably so disposed and positioned, relative to the currency-scanning plane, as to scan a different quarter portion of the paper currency. Accordingly, the scanner apparatus of the present invention comprises a scanning zone, at least one light-emitting diode, at least one light detector, and a waveguide. The scanning zone of the scanner defines opposed sides and is dimensioned to enable a scannable article to be disposed between the opposed sides thereof. The light-emitting diode device is disposed on one side of the scanning zone, and is capable of providing light of discreetly-different energy levels. Also, the light-emitting diode device is so disposed relative to the scanning zone as to enable light associated with such diode device to be able to scan at least a portion of the scannable article. The light-detector device is spaced from the light-emitting diode, and is also so disposed relative to the scanning zone of the scanner, that light emanating from the light-emitting diode device and thereafter passing through the scanning zone, is able to provide information, enabling the light detector to characterize the article scanned in the zone. The wave guide is disposed between the light-emitting diode device and scanning zone. The wave guide defines at least one light-admitting aperture and at least one light-reflective surface, wherein the light-admitting aperture and the light- reflecting surface cooperate to direct light from the light-emitting diode device toward the scanning zone, and to focus such light centrally along a path traveled by such light toward the detector. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a conventional apparatus for scarining currency. Figure 2 is a schematic view of a first embodiment of the scanner apparatus of the present invention. Figure 3, also a schematic, shows a lower portion of the embodiment of Figure 2. Figure 4 is a bottom plan view taken generally along the plane 4-4 of Figure 3. Figure 5 A is a schematic view that depicts an illustrative example of a feature of the present invention generally shown in Figure 3, on an enlarged scale relative thereto. Figure 5B is another schematic depicting a further illustrative example of the noted feature generally shown in Figure 3, also on an enlarged scale relative thereto. Figure 6 depicts, in side view and in a schematic format, yet another preferred embodiment of the scanner apparatus of the present invention. Figure 7 depicts, in side view and also in a schematic format, still another preferred embodiment of the scanner apparatus of the present invention. Throughout the drawings, like reference numeral refer to like component parts. State-of-the-Art Scanner and Problems Associated Therewith Figure 1 depicts, as a schematic view, a conventional apparatus 100 for scanning paper currency. The apparatus 100 includes an opening or aperture 102 typically taking the form of an elongated slot for inserting paper currency into the apparatus 100. The currency-insertion aperture or opening 102 includes an upper boundary 104 and a lower boundary 106. Currency (not shown) inserted through opening 102 into the apparatus 100 ideally is caused to travel along a path 110 (shown in dotted line) that may be thought of as a plane extending into the page of Figure 1 of this patent specification. The currency-scanning apparatus 100 also includes a plurality of light- emitting diodes (LEDs) 114 that are spaced from the lower boundary 106 generally uniformly along the length thereof. As was noted above, twelve or more of the above-described LED packages 114 must necessarily be incorporated into the scanning apparatus 100, if the apparatus 100 is to verify currency authenticity and value, thereby to achieve its commercial purpose. Also incorporated into the conventional arrangement depicted in Figure 1 is a corresponding plurality of collimating lenses 116, wherein each lens 116 is similarly spaced from the lower boundary 106 generally uniformly along the length thereof. In the conventional scanner arrangement illustrated, each such collimating lens 116 is associated with its corresponding LED package 114. Accordingly, as a result of the scanner arrangement shown, each such collimating lens 116 is located between the lower boundary 106 and its associated LED package 114. The currency-scanning apparatus 100 of Figure 1 further includes a corresponding plurality of simple planar convex light-focusing lenses 122. Each such simple planar convex light-focusing lens 122 is disposed between the upper boundary 104 and an associated currency authenticity/valuation detector 120. In ideal situations, each such simple planar convex light-focusing lens 122 is capable of focusing light passing through the paper currency onto a preselected portion (or point) of its associated detector 120. In operation, the plural simple planar convex light-focusing lenses 122 focus light to enable the plural detectors 120 to detect certain light-energy levels, for the purpose of verifying the authenticity of the inserted currency as well as detecting the value thereof. The currency-scanning apparatus 100 shown in Figure 1 accordingly necessarily further includes a corresponding plurality of detectors 120, each of which is capable of verifying the authenticity of currency and detecting the relative value thereof. Moreover, the plural detectors 120 (i.e., twelve or more) are by current design spaced from the upper boundary 104 generally uniformly along the length thereof. Each detector 120 is associated with a corresponding light-focusing lens 122 as well as with a corresponding LED package 114 and collimating lens 116, for reasons stated above. Conventional scanners still have problems. As was mentioned above, movement of paper currency above or below its desired scanning plane may take the bill out of the focal point of light-focusing convex lens 122. Also, paper by its nature diffuses light. As a result, even when a conventional apparatus 100 incorporates the plural LED packages 114 described above and the associated pluralities of collimating lenses 116, convex lenses 122, and detectors 120, the resultant diffused light that passes through a bill located in the scanning plane 110, which light is thereafter focused, may fall short of one or more of the plural detectors 120 entirely, or the light rays passing through one or more of the plural convex lens 122 may focus light from the scanned bill behind a desired detection zone of an associated detector 120, either of which result is undesirable. Aligning each LED package 114 with associated lenses 116 and 122 is a major obstacle faced by current scanner manufacturers and misalignment is common. Unnecessary complexity may result in excessive cost of the apparatus, and may affect reliable operation thereof. It is therefore desirable to reduce the complexity of a scanner apparatus by reducing the number of LED packages and associated components now required in state-of-the-art paper-currency scanners, thereby allowing for reduction of the above mentioned associated components, resulting in a less complex apparatus. Multiplicity of component parts may undesirably impact on volume requirements and associated appearance considerations of conventional scanners. To minimize volume requirements, reduction of the number of components may therefore become desirable. It is further desirable that the resultant less-complex apparatus nevertheless be capable of verifying the authenticity of currency and determining its denomination or value with very high reliability and accuracy and statistically significant precision. Detailed Description of Preferred Embodiments Figure 2 depicts, in schematic, one embodiment of the scanner apparatus 200 of the present invention. Apparatus 200 is preferably used to scan paper currency to verify authenticity and determine the value thereof. Currency-scanner apparatus 200 includes no more than four light-emitting diode packages 214, the location of which will be described below in connection with Figure 4. Each such light-emitting diode (LED) package 214 is able to produce light having a plurality of discreetly-different wave lengths, each of which has a discrete energy level. Preferably, each LED package 214 is capable of producing light having two to ten discretely different energy levels. More preferably, each LED package 214 is able to produce light having four to eight discretely-different energy levels depending on the wavelengths. The most preferred LED package 214 (shown in Figure 4) is capable of producing light having six different energy levels. In particular, the most preferred LED package 214 of the currency scanner apparatus 200 is able to produce light having associated discretely-different wavelengths of 470, 505, 620, 730, 840 and 940 nanometers. In particular, Figure 4 depicts schematically six apertures on LED package 214, wherein the apertures 218A, 218B, 218C, 218D, 218E and 218F are each associated with a different one of the six wave lengths of light that are mentioned immediately above. The scanner apparatus 200 of the present invention does not require a collimating lens. Instead, the scanner apparatus 200 of the invention includes a wave guide 230. Wave guide 230 includes polished clear windows 232 located on opposite ends thereof. The windows 232 are so disposed relative to an associated LED package 214 as to enable light from such associated LED package 214 to enter the wave guide 230. The illustrated wave guide 230 further includes side surfaces 234 as well as a grooved surface 236 for directing light from the LED packages 214 toward the direction of paper currency that is caused to travel along a path 210 (shown in dotted line) that may be thought of as a plane extending into the page of Figure 2 of this patent specification. Side surfaces 234, disposed at opposite ends of wave guide 230, are metalized. Each metalized surface 234 is so disposed relative to an associated LED package 214 as to direct light from such LED 214 toward scaniiing path 210, as described above. Grooved surface 236 includes individual grooves 238-240, depicted schematically in Figures 3 and 4. Each groove 238 shown is illustrative of a groove formed at an upper junction of angled adjacent surface portions of grooved surface 236. Whereas, grooves 239 and 240 are illustrative of grooves formed at an intermediate junction and at a lower junction, respectively, of angled adjacent surface portions of the grooved surface 236. Grooved surface 236 is symmetric about axis A-A (Figure 3) for several reasons. First, the light sources (provided by the LED packages 214) are longitudinally disposed at opposite ends of the wave guide 230. Also, the angled side surfaces 234 of the wave guide 230 are so disposed relative to their associated LED packages 214 as to concentrate reflected light of six discrete, different wavelengths toward central axis A-A. Moreover, the grooved surface 236, itself, is made up of minute illustrative grooves 236A (Figure 5A) and grooves 236B (Figure 5B), designed to concentrate light centrally. Further in that regard, grooves 236B (Figure 5B), which are triangularly formed and located closer to windows 232, are so dimensioned as to cause a first portion of the six wavelengths to so reflect from the side surfaces 234 and grooved surface 236 as to be concentrated centrally toward axis A-A. Proceeding closer to central axis A-A minute grooves 236A are even more closely spaced (Figure 5A) so as to cause a second portion of the six wavelengths of light from LED packages 214 to be concentrated centrally toward axis A-A. Additional minute grooves (not shown) are accordingly symmetrically formed in the grooved surface 236 relative to the central axis A-A until all six wavelengths of light from LED package 214 are centrally concentrated. Brief reference is made to Figure 3 to note that the depicted angled orientation of grooved surface 236 must further consider the angle orientation of the associated minute grooves 236A (Figure 5A) and 236B (Figure 5B) to achieve the effects disclosed herein. Grooved surface 236, by design, thus includes minute grooves, the dimensions of which diminish symmetrically toward central axis A-A, to accommodate the different frequencies of the six different wave lengths, enabling light of uniform intensity to scan paper currency along path 210. The net effect, which is cost efficient, is a uniform "bar" or rectangle of light, produced as a result of using a minimal amount of light energy. The illustrated wave guide 230 (Figures 2 and 3) is a so-called "dove" prism made of a commercially-available acrylic material which is both highly transparent and able to transmit light with high efficiency, thus achieving substantially total internal reflection. The side surfaces 234 and grooved surface 236 are metalized with commercially-available highly reflective material for reflecting light centrally toward axis A-A and path 210, as noted above. Further in this regard, grooved surface 236, itself, is especially designed to concentrate light of discretely-different wave lengths and associated energy levels uniformly toward an article such as currency being scanned by apparatus 200. In Figure 6, there is shown a scanner apparatus 300 that includes wave guide 330 and LED packages 314, and spaced-apart light-reflective side surfaces 334 disposed on opposite longitudinal ends of wave guide 330. Wave guide 330 further includes a pair of spaced-apart polished, clear light-transmissive windows 332, each of which is so located adjacent an associated LED package 314, as to achieve a "light bar" effect noted above. In lieu of a grooved surface (described above) this embodiment of the invention incorporates into the design of the illustrated wave guide 330 a holographic, variable light-shaping diffuser surface 350 between the windows 332. The light-shaping diffuser surface 350 is upwardly light-reflective, as a result of a layer of commercially-available metallic material 352 that is applied to the underside thereof. In particular, the variability that is incorporated into the light-shaping diffuser surface 350, using techniques disclosed for example in a commonly assigned copending patent application, is able to achieve the same effect of the variably grooved surface 236 of scanner apparatus 200, to focus within wave guide 330 internally-reflected light toward central axis B-B of apparatus 300 and upwardly, achieving the noted "light bar" effect, for the purpose of scanning an article. To achieve such an effect, a central portion 360 (depicted in Figure 6 between vertically-disposed dotted lines) preferably has a major light output distribution angle of 80 to 95 ° along the length as well as a minor light distribution angle of 25 to 35 ° across the width of paper currency being scanned. Light-shaping diffuser surface 350 further includes spaced-apart end portions 362, each of which is located adjacent an associated LED package 314. Further, each portion 362 preferably has a major angle of 60 to 75 ° along the length as well as a minor angle of 10 to 25 ° across the width of currency scanned along path 310 by scanner 300. To receive the centrally-concentrated, upwardly-disposed light from the light-shaping diffuser surface 350 of wave guide 330, the apparatus further includes a light-shaping surface diffuser layer 370 disposed above wave guide 330, as shown in Figure 6. Layer 370 also preferably has a major light distribution angle of 80 to 95 ° along the length as well as a minor light distribution angle of 25 to 35 ° across the width of paper currency being scanned, as does central portion 360. Moreover, layer 370 and central portion 360 have their light-shaping diffuser major and minor angle orientations aligned, to achieve the above-noted effect. An optional sheet of commercially-available prismatic material 380 may then be disposed on the opposite side of path 310 relative to light-shaping surface diffuser layer 370, to reduce the effect of light coming off of the backside of currency being scanned. Yet another embodiment of the scanner apparatus 400 of the present invention, as shown in Figure 7, includes wave guide 440 and light-shaping surface diffuser layer 470 disposed thereabove, as in scanner apparatus 300. (Please refer to Figure 6.) A plurality of detectors 420, located on the opposite side of path 410 relative to wave guide 440, are so disposed relative to each other along the length of path 410 as to verify the authenticity as well as determine the value of currency being caused to travel along path 410 by use of a conventional mechanism (not shown). A single row of detectors 420 may include eight to twelve individual detectors 420, depending on dimensions of scanned currency. A sheet of commercially-available prismatic material 480 is disposed between path 410 and the light-shaping surface diffuser layer 470, to reduce the effect of light scattering, and collimating the light between diffuser layer 470 and path 410. Between detectors 420 and path 410 is at least one sheet of another commercially-available prismatic material 482, which preferably has its prismatic grooves (not shown) disposed longitudinally relative to the currency that is caused to travel along path 410, namely, out of the plane of the page of Figure 7. An additional sheet of still another commercially-available prismatic material 484 may be disposed between prismatic material sheet 482 and detectors 420, to reduce the effect of light scattering between path 410 and detectors 420. What has been illustrated and described herein is a novel scanner apparatus for paper currency. While the scanner apparatus of the present invention has been described with reference to several preferred embodiments, it is to be understood that those skilled in the art, after reading this disclosure, will appreciate the value of the invention, and will know of certain equivalents of elements and components disclosed herein. The present invention, therefore, is not to be limited to the presently preferred embodiments, but rather is to be provided the broadest possible scope, as the appended claims will permit.

Claims: CLAIMS What is claimed is the following: 1. A scanner apparatus comprising: (A) a scanning zone defining opposed sides and dimensioned to enable a scannable article to be disposed between the opposed sides thereof; (B) a light-emitting diode device, disposed on one side of the scanning zone and spaced from the scannable article, wherein the light-emitting diode device is capable of providing light of a plurality of discreetly-different energy levels, and wherein the light-emitting diode device is so disposed relative to the scanning zone as to enable its associated light to scan at least a portion of the scannable article; (C) a detector device, spaced from the light-emitting devices, and so disposed relative to the scanning zone that light from the light-emitting diode device and passing through the scarining zone enables the detector device to characterize an article being scanned; and (D) a wave guide disposed between the light-emitting diode device and the scanning zone, wherein the wave guide defines a light-admitting aperture and a light-reflective surface, wherein the light-admitting aperture and the light-reflecting surface cooperate to direct light from the light-emitting diode device toward the scanning zone, and to focus such light centrally along a path traveled thereby toward the detector device. 2. The scanner apparatus of claim 1, wherein the scannable article passing through the scanning zone is characterized as paper currency. 3. The scanner apparatus of claim 1, wherein the light-emitting diode device is characterized as no more than about four light-emitting diode packages. 4. The scanner apparatus of claim 3, wherein each such light-emitting diode package is capable of emitting light of wavelengths of 470, 505, 620, 730, 840 and 940 nanometers. 5. The scanner apparatus of claim 1, wherein the light-emitting diode device is characterized as being capable of providing light of from two to ten discreetly-different energy levels. 6. The scanner apparatus of claim 1, wherein the light-emitting diode device is characterized as being capable of providing light of from four to eight discreetly-different energy levels. 7. The scanner apparatus of claim 1, wherein the light-emitting diode device is characterized as being capable of providing light of six discreetly-different energy levels. 8. The scanner apparatus of claim 7, wherein the diode device is capable of emitting light of wave lengths of 470, 505, 620, 730, 840 and 940 nanometers, wherein each such wave length corresponds to one of the six discreetly-different energy levels. 9. The scanner apparatus of claim 1, further including a light-focusing lens disposed between the scanning zone and the detector device. 10. The scanner apparatus of claim 1, further including an optically- transmissive prismatic element disposed between the scanning zone and the detector device. 11. The scanner apparatus of claim 1, wherein the detector device is characterized as a plurality of spaced-apart light-detector elements collectively arranged transverse to the scanning zone. 12. The scanner apparatus of claim 11, further including a light-shaping surface diffuser disposed between the plurality of light-detector elements and the scanning zone. 13. The scanner apparatus of claim 1, wherein the light-emitting diode device is characterized as at least two spaced-apart light-emitting diode packages, wherein the wave guide is characterized as elongated and defining spaced-apart end portions, wherein the wave guide includes two spaced-apart optically-transmissive windows, wherein each such window is located adjacent one of the wave guide end portions, and wherein each such window is associated with a corresponding one of the light-emitting diode packages for allowing light to enter the wave guide, wherein the wave guide further includes internal light-reflective surfaces that receive light from the diode packages via at least one of the windows, wherein the internal light- reflective surfaces direct light within the wave guide centrally from the end portions relative to the windows and thereafter toward the scanning zone. 14. The scanner apparatus of claim 13, wherein each such light-emitting diode package is capable of emitting light of wave lengths of 470, 505, 620, 730, 840 and 940 nanometers. 15. The scanner apparatus of claim 13, wherein the internal light- reflective surfaces of the wave guide are characterized as including a pair of reflective surfaces each of which is located adjacent one of the spaced-apart wave guide end portions, wherein each such end portion reflective surface is located adjacent a corresponding one of the light-emitting diode packages, wherein each such end portion reflective surface is so disposed relative to its associated light- emitting diode package that light from its associated light-emitting diode package reflects from such end portion reflective surface and is concentrated between the end portion reflective surfaces, and wherein the internal light-reflective surfaces of the wave guide are further characterized as including an intermediate reflective surface located between the end portion reflective surfaces, wherein the intermediate reflective surface is so disposed relative to the end portion reflective surfaces as to receive concentrated light from the end portion reflective surfaces and reflect such concentrated light uniformly toward the scarining zone. 16. The scanner apparatus of claim 15, wherein the intermediate reflective surface defines a light-reflective grooved surface defining a plurality of light-reflective grooves, wherein each of the light-reflecting grooves is so spaced from, disposed toward and dimensioned relative to the end portion reflective surfaces as to receive reflected light from the end portion reflective surfaces and concentrate ' such light therebetween. 17. A method for scanning a light-transmissive scannable article comprising: (A) introducing the light-transmissive scannable article into a scan zone; (B) introducing light having a plurality of discreetly-different energy levels into a substantially totally internally reflective device; (C) concentrating light introduced into the substantially totally internally reflective device along a path, wherein the path defines the shorted distance between the reflective device and the san zone; (D) reflecting the concentrated light within the internally reflective device in a manner so as to provide the concentrated light with substantially uniform intensity and thereafter to cause the concentrated light of uniform intensity to travel along the path; (E) directing the concentrated light of uniform intensity traveling along the path into the scan zone, for scanning the scannable article with the concentrated light of uniform intensity; and (F) scanning the scannable article in the scan zone with the concentrated light of uniform intensity in the scan zone, to produce information characteristic of the article. 18. The method of claim 17, including the step of analyzing the concentrated light of uniform intensity after said concentrated light passes through the article. 19. The method of claim 17, including the step of comparing the scannable article characteristic information to a standard, to verify authenticity of the scannable article.

Inventors: HOSSEINI ABBAS, SAVANT GAJENDRA D, SHIE RICK L, WANG SAN ZHUANG, HOSSEINI, ABBAS, SAVANT, GAJENDRA, D., SHIE, RICK, L., WANG, SAN, ZHUANG
Applicants: PHYSICAL OPTICS CORP, PHYSICAL OPTICS CORPORATION
Application year: 2001
Main classification: G06K7
IPC codes: G06K7, G06T1, G07D7