Abstract:
A card (document or instrument) embodying the invention includes a pattern formed between the top and bottom surfaces of the card, whereby the card, when illuminated by a light source, produces a unique output light pattern which can be detected by a photo sensor. The formed pattern may take any number of different shapes ranging from stripes of different size and spacing, as in a bar code, to complex two-dimensional shapes and images. The pattern formed between the top and bottom surfaces of a card may include light pipes (paths) extending from one side of a card to one, or more, other side(s) of the card. Alternatively, the pattern formed between the top and bottom surfaces may include a bundle of optical fibers extending from one side of a card to one, or more, of the other sides of the card. Alternatively, the pattern formed between the top and bottom surfaces of the card may include light pipes or optical fibers extending “vertically” between these two surfaces. Alternatively, an image may be embedded between the top and bottom surfaces.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to valuable cards, instruments and documents and, in particular to methods and apparatus for patterning or encoding these cards, instruments and documents. 
     For ease of discussion, the invention will be illustrated using cards such as commonly used plastic cards. However, it should be understood that in the specification to follow and in the appended claims, when reference is made to “cards”, instruments and documents are also included, although not specifically identified as such. 
     Cards of interest may be used, for example, to identify a person or object and/or they may be used as a value card (i.e. a debit card or credit card) to withdraw money from a machine. Because of the value of these cards there are counterfeiters who make “false” cards which attempt to imitate “true” or “valid” cards. To enhance the security of the cards it is known to add additional security “features” to the surface of the cards. These added security features can take the form of a hologram or a spatial dependent optical image or ghost images strategically placed on the surface of the card. 
     In a certain group of applications the security features are dependent on a person actually checking that the cards&#39; security features are present and/or intact. A problem exists with these applications in that there are many instances where the person responsible for checking the validity of the card, such as a cashier, does not actually look at the credit card and simply mechanically “swipes” the card through a card reader, such as a slot reader. When this occurs, the security features present on the card such as the hologram on the surface of the card and the signature on the back of the card are rendered useless. 
     It is therefore desirable and/or necessary to develop a more reliable and automatic means for impeding the falsification of a card and to check whether these means are present. To this end, card readers may be used to automatically read or sense the security related information contained on a card to identify whether a card is valid. Also, to increase the security of the cards more features may be added to make it much more difficult to counterfeit these cards. Examples of means for enhancing the security of cards and for sensing (reading) the presence of the enhanced security means are described, for example, in our presently pending patent applications, identified below, the teachings of which are incorporated herein by reference: (a) Multi Sensor Information Reader filed Apr. 7, 1998 and bearing serial number 09/056134, and (b) Method And Apparatus For Impeding The Counterfeiting Of Cards, Instruments And Documents filed May 26, 1996 and bearing serial number 09/084,844. 
     A disadvantage of increasing the number of security features placed on the top and bottom surfaces of a card is that it uses up valuable space, which many card manufacturers would prefer to use for advertising. This disadvantage is overcome in cards made in accordance with the invention. 
     SUMMARY OF THE INVENTION 
     A card embodying the invention includes a pattern formed between the top and bottom surfaces of the card, whereby the card, when illuminated by a light source, produces a unique output light pattern which can be detected by a photo sensor. 
     Generally, the pattern may take any number of different shapes ranging from stripes of different size and spacing, as in a bar code, to complex two-dimensional shapes and images. The pattern formed between the top and bottom surfaces of a card may include light pipes (paths) extending from one side of a card to one, or more, other side(s) of the card. Alternatively, the pattern formed between the top and bottom surfaces may include a bundle of optical fibers extending from one side of a card to one, or more, of the other sides of the card. Alternatively, the pattern formed between the top and bottom surfaces of the card may include light pipes or optical fibers extending between these two surfaces. Alternatively, an image may be embedded between the top and bottom surfaces. 
     Certain of the cards embodying the invention may be illuminated from the top or the bottom surface to produce an output light pattern along at least one edge of the card. These cards will normally be formed such that the illuminated surfaces are formed of translucent material. 
     Other cards embodying the invention may be illuminated along one of their edges to produce an output light pattern along another edge. These cards may be formed with opaque top and bottom surfaces. 
     Certain other cards embodying the invention may be illuminated along a selected one of their edges to produce an output light pattern along another edge and to also produce an output light pattern out of one (or both) of the top and bottom surfaces of the card. In this case the surface from which an output light pattern is produced would be formed of a translucent material. 
     Still other cards embodying the invention may be illuminated from the top or the bottom surface to produce an output light pattern at the other surface. In this instance both the top and bottom surfaces would be formed of translucent material. 
     A reader embodying the invention includes means for Illuminating a selected card in a predetermined manner and includes sensing means for reading and recognizing the output light pattern. In a particular embodiment of the invention, a reader illuminates a card which includes a pattern of light paths formed within the card, between the top and bottom surfaces thereof, for producing a predetermined light pattern at an edge of tile card when the light paths are illuminated. In some embodiments the light paths extend from one side (extending between the top and bottom surfaces) of a card to a second side of the card. When light is applied to the one side of the card, a light pattern is produced at the second side so that the pattern can be sensed. In other embodiments of the invention the light paths extend from one of the two surfaces of the card to a side of the card. The one surface of the card is then illuminated and the light pattern produced at the side of the card is sensed. Still further the light paths may be patterned such that the spacing between the light paths is predetermined and/or the size of each light output site may be predetermined. In certain embodiments of the invention the light paths are formed using optical fibers. 
     An advantage of cards made in accordance with the invention is that a significant amount of coded information may be produced without requiring space on the top and bottom surfaces of cards. Leaving the top and bottom surfaces of a card free is significant because these areas are precious real estate used by many card manufacturers as advertising space. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawing like reference characters denote like components; and 
     FIG. 1 is cross-sectional diagram of a prior art card including a light path; 
     FIGS. 2A,  2 B and  2 C are cut-away views of cards formed with different light patterns in accordance with the invention; 
     FIGS.  2 D 1  and  2 D 2  are side views of cards embodying the invention; 
     FIG. 3 is cut-away view of the top of a card formed, in accordance with the invention, being illuminated by a light source and with its output pattern being read; 
     FIG. 4 is a cross-sectional view of a card embodying the invention mounted on a reader and being illuminated and its light output being detected in accordance with the invention; 
     FIG. 5 is a side view of a card embodying the invention; 
     FIGS. 6A and 6B are respectively, a side view and a front view of a card embodying the invention with either one of its top and bottom surfaces being illuminated; 
     FIGS. 6C and 6D are respectively a side view and a front view of a slot reader with a card embodying the invention; 
     FIG. 6E is a cross-section of a card embodying the invention; 
     FIG. 7A is a front view of a card embodying the invention; 
     FIG. 7B is a side view of the card of FIG. 7A being illuminated in accordance with the invention; 
     FIG. 8A is a front view of a card embodying the invention with embedded bar codes; 
     FIG. 8B is a side view of the card of FIG. 8A being illuminated and read in accordance with the invention; 
     FIGS. 9A and 9B front views of cards embodying the invention formed with fiber optic bundles; 
     FIG. 9C is an isometric of a reader for reading a “fiber optic” card embodying the invention; 
     FIG. 9D is a cross-sectional diagram of a fiber optic card embodying the invention; 
     FIG. 10A is a top view of another card embodying the invention; 
     FIG. 10B is a side view of a card of the type shown in FIG. 10A; 
     FIGS. 11A and 11B are top and side view, respectively, of an insertion reader for reading cards embodying the invention; 
     FIG. 12 is a top view of still another card embodying the invention; 
     FIG. 13 is a conceptual diagram of a different card construction in accordance with invention; and 
     FIGS. 14A and 14B illustrate a method of forming cards embodying the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Applicants&#39; invention resides, in part, in the recognition that an existing technology could be modified and adapted to produce cards which could be encoded and/or patterned without the necessity of using up the surface area of the cards. 
     FIG. 1 shows a cross section of a prior art multi-layered card  9  formed such that the top and bottom layers of the card are spaced from each other to define a channel through which light can pass. The card includes a bottom layer  10  and top layer  11 . Each one of layers  10  and  11  includes an outer layer  10   a ,  11   a , respectively, made of a translucent material. Outer layers  10   a ,  11   a , have an outer surface  7 , 8 , respectively. Each one of layers  10  and  11  also includes an inner layer on which is formed a semi-reflective layer  13   a ,  13   b , respectively, spaced from each other. The semi-reflective layer may be an aluminum compound or an acrylic, or any like material. Light projected onto either one of the outer surfaces ( 7 , 8 ) of the card is captured between the reflective layers and travels between layers  13   a  and  13   b  of the card until it is emitted as a diffused light output along the side or edge of card  9 . This method uses what may be termed edge glow technology. That is, this technology uses a light reflective space formed between the two (top and bottom) surfaces of the card so as to transmit light that has been projected onto the outer surfaces of the card and entered the card, and the light is transmitted towards the edge of the card in a diffused manner. This allows the edges of the card to glow. 
     As light enters the card from either the top or bottom, the light will remain trapped within the semi-reflective material until it can escape from the edges of the card. As the light escapes from the edge of the card the edges of the card will appear to glow. This glowing phenomena can be seen, for example, by illuminating the card with a small flashlight and then visually looking at the edge of the card. To view the light coming out of the edges of the card someone has to actually look at the edge of the card to see if it is present. 
     The light outputted from the edges of a card formed in accordance with the prior art teaching is diffused and is not of significant use. However, as discussed below, Applicants recognized that the space between the top and bottom surfaces could be coded and/or patterned such that, when illuminated, a significant amount of coded information could be provided. 
     In FIGS. 2A,  2 B and  2 C, cards formed in accordance with the invention incIude light pipe patterns formed within the cards (between its top and bottom surfaces) for producing a predetermined output light pattern at an edge of the cards. That is, when a light pipe pattern is illuminated by a light source, a predetermined output light pattern is produced at the edge (side) of the card. The pattern can then be sensed or read by means of a series of electronic sensors and detectors which can accurately measure the output light pattern being emitted at the edge of the card. 
     FIGS. 2A,  2 B and  2 C show three different light pipe patterns formed within a card. In FIG. 2A shows a top view of the lower layer of a card containing a light pattern formed so as to extend from one side  12  of the card  9  and across the width of the card to the opposite side  14 . FIG. 2B shows a top view of the lower layer of a card,  9 , containing a light pattern which extends from one side  12  to another, adjacent, side  16 , at a right angle to side  12 . In FIGS. 2A and 2B the patterns may use one illumination source (as shown in FIG. 3) where the input light is projected so as to enter the edge (side)  12  of the card and the light energy is dispersed within the light pipe and then transmitted to three output sites. The light source may be a light emitting diode (LED) or any other suitable light source. For ease of illustration, in the discussion to follow, reference is made to visible light. However, it should be understood that in many embodiments of the invention, non-visible light (e.g., ultraviolet and infrared light) may be used. As shown in FIGS. 2A and 2B, the width (W 1 , W 2 , W 3 ) of each output site, as well as the spacing (d 1 , d 2 ) between the various output sites, may be controlled (varied) in accordance with a code or program to render the cards more secure. In FIG. 2C, three separate and independent light pipes (P 1 , P 2 , P 3 ) are formed between the top and bottom surfaces of the card. Each light pipe can then be illuminated with a different color LED (L 1 , L 2 , L 3 ) and then detected with a color sensitive detector array. A reader to read the cards would require that the reader be used to illuminate the cards and be programmed or designed to operate with these cards. 
     FIG.  2 D 1  shows a side view looking into the light output side  14  of the card  9 . The card  9  may have a total thickness or height (h) of approximately 30 mils. FIG.  2 D 2  shows a side view looking into the light input side  12  of card  9 . The top and bottom surfaces,  11   a  and  10   a , respectively, may each have a height of 10 mils and the coded light pattern is formed within a space also having a height of 10 mils. It should be appreciated that these values are by way of example only and that the height of each layer may be made substantially greater or smaller, so long as the total height meets the general standards required of the cards. 
     FIG. 3 illustrates that a light pipe (path) pattern  15   a  may be formed on a card  9  such that light may be inputted on one side,  12 , and a different output light pattern may be produced on the other three sides ( 16 ,  14  and  18 ) of the card. FIG. 3 also illustrates that a single light source, L 1 , may be used to illuminate the back end of the light pipe patterns shown in FIGS. 2A and 2B and that the input light energy is evenly dispersed and distributed to each of the three output sides,  14 ,  16 ,  18 , depicted in FIG.  3 . The light output emitted from each of the output sides then may be detected by an array of optical photodetectors,  30 ( 1 ),  30 ( 2 ) and  30 ( 3 ). The photodetectors (or sensors) are used to measure the parameters associated with the output illumination of the light pipes (i.e., the widths W 1 , W 2 , W 3  and the distances d 1 , d 2 ). If the characteristics of the light received at each location are not within the specification then the card is determined to be false. Again, the reader to read these cards is programmed and/or designed to work/function with the cards. As discussed below, a reader embodying the invention would include means for activating a light source and projecting the light along the edge (side) of the cards shown in FIGS. 2A,  2 B,  2 C and  3 , and would also include photosensors for sensing the output light pattern (“coded” light output). The reader would also include decoding processing and memory circuitry for comparing the sensed information versus previously stored information to determine the validity of the cards. 
     FIG. 4 shows a cross-section of the illuminator/detector system for a card mounted in a reader housing. The reader provides a light source  4  which would project input light onto, and into, one side of the card and a photodetector,  30 , for sensing the light output from another side (opposite or adjacent to the one side). Note that the illuminating system would include a light shade ( 41   a ,  41   b ) at the light input end to prevent illumination from the LEDs from skipping (passing) over the edge of the card and interfering with the detector. Likewise, the reader would include light shades ( 42   a ,  42   b ) at the light output end to allow the detector to only detect light output from the edge (side) of the card. 
     FIG. 5 shows a side (edge) of the card illustrating three site locations (S 1 , S 2 , S 3 ) from which the light energy exits the card,  9 . One method used to detect if the card has been falsified is to check the width (W 1 , W 2 , W 3 ) of the light emitted from the various location sites and the width or distance (d 1 , d 2 ) between the various site locations defining opaque areas. Similar to detecting conventional bar codes, the above detection scheme will be able to measure the precise illumination areas and the precise opaque areas. Techniques for detecting this type of information is known and need not be detailed. 
     In FIGS. 2A,  2 B,  2 C and  3 , the top and bottom surfaces ( 10 ,  11 ) of the cards may formed of an opaque material since the light output pattern is produced at one edge of the card by illuminating another edge of the card. 
     The light pipes can be made of a material that will only transmit a narrow frequency band (e.g., red, green or yellow). The optical detector will only then validate the card if the signal contains both the correct widths and the predetermined spectra. 
     Of course the bar/space pattern can be adjusted for each specific customer application. This will allow this technique to have a unique pastern (illumination/opaque) ratio for each application. 
     In the discussion above, the cards were intended primarily for use in what are known in the art as “insertion readers”, including manual or motorized insertion readers. 
     In a different embodiment of the invention the light pipe formed in a card does not extend the entire length (or width) of the card. FIGS. 6A and 6B show different views of a card. In FIG. 6A, which is a cross-sectional diagram, the light pipe extends only partially along the width on the length of the card. That is, the light pipe extends from one of the major surfaces of the card to one of the sides of the card. The light pipe is illuminated from one of the top and bottom surfaces and the light is bent a 90 degree angle and directed towards one edge of the card; where the output light signal is then detected by a detector  30   a . The embodiment of FIG. 6A enables the detection of security features by means of a reader,  101 , shown in FIGS. 6C and 6D which uses a manual “swipe” technique (e.g., slot or “swipe” reader). In a manual “swipe” application, the card  9  is typically held in the hand of a user and the lower portion of the card is then inserted and swept through the reader  101 . 
     As shown in FIG. 6C, as the card is passed through a slot reader, the LEDs will illuminate one surface of the card and cause light to be projected via holes or cut-aways  61 . When the LEDs align with the input to the light pipe, the detector  30   a  will detect the output light pattern produced at the edge of the card. If the light pattern at the edge of the card matches an appropriate configuration previously stored or programmed in the reader, then the card will be deemed to be valid. In FIG. 6A, when the card surfaces are made opaque, the cut-out  61  to let light in is required. However, note that when the card surface (e.g., surface  10  in FIG. 6A) is made of a translucent material, there would be no need for holes or cut-aways  61 . 
     Of course, the position of the light and the detector can be interchanged. Thus, in the embodiment shown in FIG. 6A, the one surface  10  of card  9  would be translucent while the other surface  11  could either be opaque or translucent, as shown in FIG.  6 E. This is true for all of the embodiments of this invention. 
     In the discussion above, energizing the light pipe pattern was accomplished by illuminating one end of a light pipe and reading the light output produced at the other end. 
     However, it is within the ambit of the invention to have an embodiment of the invention in which a pattern is completely embedded within a card, as shown in FIG.  7 A. In this example, the picture of a bull is completely embedded within the card. That is, the pattern is placed between the top and bottom surfaces of the card. As shown in FIG. 7B, the card will be placed in a reader housing such that the light is incident on one side of the card and an area detector  30   c  is placed on the other side of the card. As the card is inserted into a validation machine (reader), the LEDs illuminate one side of the card, which is made of a translucent material. Light will, therefore, pass through the card. However, in the area where the “image of the bull” is located the light will not pass through. The presence or absence of light can then be detected by an area sensor  30 C such as a CCD area sensor. If the embedded image matches the preprogrammed security image stored in the reader, the card is deemed valid 
     FIG. 8A shows an embodiment of the invention where a bar code is embedded between the top and bottom surfaces of a card. In FIG. 8A, the card material is selected so that when light is projected onto the top or bottom surface, the embedded bar codes block the light while light passes between the bars. In this embodiment, the top and bottom layers of the card would be made translucent. 
     FIG. 8B shows the basic elements needed to read the embedded bar code of FIG. 8A. A number of LEDs can be positioned opposite one surface so as to project their light onto a surface  10  of the card  9 . A linear array of photosensors  30   d  mounted facing the other surface  11  of card  9 , can sense the light passing through the card. This will allow the detector to be a linear photosensor as opposed to a more expensive area sensor. The linear and/or area sensors could be charge coupled devices (CCDs) or any suitable sensor. The image or bar code can be opaque with the top and bottom layers of the card being translucent or, vice versa, the image may be translucent and the surrounding area being opaque. Thus, in the embodiments shown in FIGS. 7A,  7 B,  8 A and  8 B, light can be projected onto one surface of a card in which a pattern is embedded and a patterned (or coded) light output is produced at the other surface. The patterned or coded light output can then be sensed or read by means of photosensors which can then provide signals to known detecting and processing circuits. 
     FIG. 9A illustrates an embodiment of this invention where the card is manufactured with a set of optical fibers embedded between the top and bottom surfaces of the card,  9 . In FIG. 9A, a multiplicity of fiber optic light pipes (a fiber optic bundle) are shown distributed across the width of the card. The layer of fiber optics could also be placed across the entire length of the card or from one side to an adjacent, perpendicular, side. In FIG. 9A, a light source would illuminate one side (edge) of the card as shown by the arrow marked “LIGHT IN” and a light output would be produced at another side (edge), as shown by arrow marked “PATTERNED LIGHT OUT”. In this embodiment, different ones of the optical fibers could be selected to have different colors or to pass different wavelengths. Also, the spacing of the optical fibers could be made to vary. 
     It should be noted that a card may be personalized (customized) by, for exanple, breaking the fiber strands with a laser. In doing so each card can be personalized to have its own unique pattern, as shown in FIG.  9 B. 
     As shown in FIG. 9B, selected groups of fiber optic strands many be cut (i.e. vaporized) with a laser (or by any other suitable means), as shown by the black stripes  91 ,  92  and  93  in FIG.  9 B. Therefore, the broken strands of optical fibers will not carry light from the light input end of the card to the light output end. In this embodiment, all the fibers could be made identical in terms of their transmissive properties. By cutting selected groups of fiber optic strands a unique pattern can be produced and subsequently detected. However, in FIG. 9B, if the top or bottom surface of the card is translucent, the light input will produce light “marks” at  91 ,  92  and  93 . Therefore, an area reader positioned over a surface of the card for sensing the light emitted at the surface of the card could be used to identify the presence of a light output pattern on the surface of the card. 
     As shown in FIG. 9C, a reader  91  capable of reading a card of the type shown in FIGS. 9A and 9B includes a light source to illuminate one edge of the card with an optical detector  95  located along a different edge and another optical detector  97  to read one of the surfaces of the card. The detector  97  is then programmed to scan the surface area of the card and to detect where the laser has burned the end of the fiber bundles. As the light leaks out of the end of the fiber bundle that is embedded within the card, it is possible to detect the location where the fibers have been burned. Then the distance between each of the laser cuts (d 1  and d 2 ) can be calculated and the information can then be stored on an information storage media on the card (such as a magnetic stripe or an integrated circuit memory). 
     FIG. 9D is a side (cross-sectional) view of the card  9  showing an illuminated pattern. Note that the optical fibers are shown placed side by side. However, they could as well be spaced from each other. FIG. 9D shows that the fibers could be of 10 mils in diameter sandwiched between a top layer  11   a  and a bottom layer  10   a . In the example of FIG. 9D, the height of the package is approximately 30 mils. However, it should be appreciated that the size of the optical fibers and the thickness of the top and bottom layers may be varied considerably. 
     FIG. 10A illustrates yet another embodiment of the invention. The card of FIG. 10A may be formed by randomly placing optical fibers of different shapes, sizes and colors and/or randomly forming patterns of like colored optical fibers between the two surfaces of a card. The random pattern created can be read, sensed and recorded and then assigned to a particular individual as his signature or finger print card. The patterns of FIG. 10A, formed randomly, as suggested, would be truly unique. The patterns would be read as shown in FIG. 10B by illuminating one surface and sensing the patterned (coded) light out. 
     The fingerprint parameter can be stored on an information storage media such as a magnetic stripe or an IC memory located on the card. When the card is inserted into the validation reader, the unique fingerprint must match the data stored in the card into validate the card. Otherwise, the card will be rejected as invalid. 
     As noted above, readers/scanners to illuminate the smart “light cards” embodying the invention and to sense the light pattern output may include an insertion reader (motorized or manual) or a slot reader, as shown in FIGS. 11A and 11B. 
     FIG. 11A is a top view of an insertion reader showing an optical fiber type card  9  being inserted into the reader carriage with a light L 1  illuminating one side of the card and a photodetector  95  for sensing the light pattern outputted on the opposite side of the card. The reader may include an optimal magnetic stripe head or integrated circuit (IC) card reader  111 . FIG. 11B is a side view of the reader showing an area photodetector  97  overlying the card  9  to sense the light pattern output emitted from the surface of the card. 
     It should be evident that the patterning and encoding of cards, as taught herein, may be combined with other prior art security enhancing means for rendering cards embodying the invention even more difficult to counterfeit. 
     FIG. 12 is a not to scale isometric drawing of a card (or other instrument) to illustrate that optical fibers and/or light pipes defining a predetermined pattern (or used to form a pattern) may be mounted parallel to the sides of the cards. A light input signal is then applied to one of the major surfaces of the card (e.g., the top surface) and a patterned (or coded) light output signal is produced at the other one of the major surfaces of the card (e.g., the bottom surface). The card could be any other instrument such as a CD-ROM or disc. 
     It should be appreciated that the various embodiments of this invention could be incorporated into documents such as passports or visas. 
     It should also be appreciated that, as shown in FIG. 13, cards, instruments and documents embodying the invention may include a light pipe or optical fiber sandwiched between two surfaces. Depending on the application, the surfaces may both be opaque, may both be translucent, or one may be opaque and the other translucent As shown in FIGS. 14A and 14B, it should be appreciated that cards embodying the invention may be formed by first taking a substrate material  140  which may be opaque or translucent and which will eventually form the top or bottom surface of a card. The substrate material will normally have a thickness in the range of 1 to 15 mils. However, for purpose of illustration it is shown to be 10 mils in these figures. An acrylic material  142  may then be formed on top of the substrate, as shown in FIG.  14 B. The material  142  may then be patterned by any known techniques to produce a light pipe as shown in FIG. 14A. A cover (not shown) may then be placed over the pattern previously formed to produce a card embodying the invention. It should be appreciated that this is by way of illustration only and any suitable means for making and encoding the space between the top and bottom surfaces of the card is within the scope of the invention.