CA2125323A1

CA2125323A1 - Bar code incorporated into holographic display

Info

Publication number: CA2125323A1
Application number: CA002125323A
Authority: CA
Inventors: Joseph Katz; Emanuel Marom; Boris Metlitsky; Jerome Swartz
Original assignee: Symbol Technologies LLC
Current assignee: Symbol Technologies LLC
Priority date: 1994-06-07
Filing date: 1994-06-07
Publication date: 1995-12-08

Abstract

In order to improve security for holographic labels which are positioned on a substrate base, a bar code symbol with regions of different light reflective properties is holographically recorded on the base. The base may be, for example an information card, such as a credit card, a label, or a container for a product. The bar code symbol can be recorded so that it is visible to the eye in white light (e.g., as a rainbow hologram) or 50 that it requires an appropriate reference beam for reconstruction. A reading apparatus (e.g., a bar code reader) directs light at the holographic bar code symbol and detects the reflected optical information with a detector such as a CCD array.
The reading apparatus can be a stand-alone device or, in the case of a credit card, can be incorporated into a conventional swiper for reading magnetic information on a strip on the card. A non-holographic bar code symbol can also be provided on or near a holographic display element, e.g., a rainbow hologram. The bar code can be positioned adjacent the display, or placed in a window within the display, or etched or embossed on the display. A system is also provided for authenticating a holographic display on an information card such as a credit card. A display is illuminated and a reflected beam directed at a holographic record which was previously produced from a signal, known to be authentic, and a reference. The reflected beam is used to reconstruct a reference beam. A sensor receives the reconstructed reference and it is then determined if the display is authentic.

Description

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~I25323 A V~ DOC~ 1~0t 04873/007001 RA~ COD~ TNCO~2PORATFn TNT0 HOr~OGRAPHIC DISPr~Y
This application i8 related to the copen~ aro~
et al. application entitled "Hologram Authentication~ ~iled S on-even date herewith.

Backqround of the Invention This invention relates to holographic display elements used for authentication and to the use of bar codes for identification and authentication.
In order to discourage the fraudulent manufacture of information cards, such as credit cards, card manufacturers produce a card that includes a holographic display. A
hologram i8 a recording of an interference pattern between two beams of light, usually referred to as the signal beam and the reference beam. The signal beam usually includes the image to be recorded, and the reference beam i8 a beam of light, usually of constant distribution, i.e., plane of spherical wavefront. Typically, another reference beam, similar to the one used to record the hologram, i8 used to reconstruct the signal beam, which then produces an identifiable image. For many holograms, one cannot identify an image without reconstruction.
The holograms typically used on credit cards are what are known as rainbow holograms. They are produced by placing the image to be recorded near the surface of the holographic substrate during recording. These holograms are visible in ordinary, white light and should be familiar to most holders of credit cards. The rainbow hologram can be mass produced on sheets of metalized embossing substrate, and stamped onto credit cards. Such holograms are a deterrent to counterfeiting because the production requires an expensive manufacturing investment.

212~323 Some identification cards, e.g. so~e library cards, provide individual information about a cardholder with ~
code such aq a bar code 8ymbol. Bar code symbols are formed from bars or elements that are typically rectangular in shape with a variety of possible widths. The specific arrangement of elements defines the character represented according to a set of rules and definitions specified by the code or ~symboloqy~ used. The relative siZQ of the bars and apaces is determined by the type of coding used, as i8 the actual size of the bars and spaces. The number of characters per inch represented by the bar code symbol i8 referred to as the density of the symbol. To encode a desired sequence of characters, groups of elements are concatenated together to form the complete bar code symbol, lS with each character of the message being represented by its own corresponding group of elements. In some symbologies a unique "start" and "stop" character is used to indicate where the bar code begins and ends. A number of different bar code symbologies exist. These symbologies include, e.g., UPC/EAN, Code 39, Code 49, Code 128, Codabar, Interleaved 2 of 5, etc.
In order to increase the amount of data that can be represented or stored on a given amount of surface area, several new ~ar code symbologies have recently been developed. One of these new code standards, PDF417, introduces a ~two-dimensional" concept by stacXing rows of characters vertically instead of extending the bars horizontally. That is, there are several rows of bar and space patterns, instead of only one row. Thus, bar codes include not only the traditional rectangularly-shaped bars and spaces, ~ut any form of symbol in which different port~ons of the symbol have different light reflecting characteristics.

.

B~r codes are scanned to trans~orm the graphic symbol ~lemQnt~ into ~lectrical 8ignals, which ar~ then decoded ~nto character8. A 8canning system uses a light sourcQ, typically a gas or semiconductor laser, which i~
direct~d to thQ symbol or bar code by a lens or other optical component~. The sCanner functions by repetitively scanning the light beam in a path or series of paths across the symbol. Scanning systems also includQ a sensor or photodetQctor which detects light re~lected fron the sy~bol.
A portion of the reflected light is detected and converted into an electrical signal, and electronic circuitry or software decodes the electrical signal into a digital representation. The ~ymbol is decoded according to thQ
coding technique used, erg., the Uniform Product Code tUPC) on many supermar~et items.

Summary of the Invent~on In ~ ~irst aspect, thQ invention features a label with a bar code symbol holo~raphically recorded. In preferred embodiments, the symbol can be a rainbow hologra~
visibl~ in white light, or may be holographically recorded 80 that the symbol i8 only visible when reconstructed ~ith an appropriat~ refQrence beam. ThQ 5y~bol can alternatively be realizQd as ~ sQriQ~ of gratings ~hich cause bur~t~ of llght to ~e reflected when illu~inated. The holographically recordQd bar code ~ymbol may include in the sa~Q hologra~ a graphic di~play ele~ent, or such a display ele~ent may be separately positione~ on the same base on which the element i~ positioned. The label can be positioned on a product, or on the plastic base of an identification card, or affixed to any other label, material or ob~ect to be identified.
In a second aspect, the invention feature~ a bar code reader ~or reading a holographic bar code sy~bol on a -"
lab~l. In preferred embodiment8, the ~y~bol ~ay b~
recon~tructed vith ~n appropriate reference bea~ and a real image obtained. A detector, such a~ a CCD array c~n be used to receive the real image and circuitry to process the output of the CCD array. Alternatively, a detector and relay lens can be positiOned to receive a ~irtual image of the ~ymbol.
In a third aspect, the invention features an ob~ect, ~uch as a credit card, which include~ a holographic di~play element and a bar code ~ymbol positioned in proximity to the display element. The display element and symbol are preferably covered by a transparent layer of material. The di~play element discourages counterfeiting by making the card more expensive for counterfeiters to produce, and the bar code symbol adds additional security while providing infor~ation. The bar code symbol in these embodiments can be read with a conventional flying spot scanner without interference from the element.
In a fourth aspect, the invention ~eatures an apparatua for reading both the magnetic information strlpe of an information card and a bar code symbol in a single swipe. In pre~erred embodiments, the illumination source and detection apparatus can be placed within or next to a swiper used to read magnetic information, such that the b~r code symbol can be read in the same swiping motion used to read the magnetic information. Thi5 arrangement would enable one to obtain optical information without extra steps and ~eparate pieces of eguipment.
Other features and advantages of the invention will be apparent from the following description of a preferred embodiment, and from the claims.

. .

~rtef Desçription o~ the Drawinqs FIGS. 1-3 are pictorial representations o~
holographic di~plays with incorporated bar code.
FIG. ~ i~ a pictorial view of two reference beams S and two signal beams.
FIG. 4A i~ a schematic of an apparatus to reconstruct a bar code holographically recorded.
FIG. 5 is an optical reader within a magnetic cwiper channel.
FIG. 6 is a pictorial view of a card in a swiper channel with both magnetic and optical readers, taken through plane 6 of FIG. 5.
FIG. 7 i8 a pictorial representation of an identification card with gratings.
FIG. 8 is a pictorial representation of a system to authenticate a holographic d~splay.
FIGS. 9A and 9B represent patterns that might appear in an image plane for an image with satisfactory and unsatisfactory correlation, respectively.
FIGS. 10 and 11 are pictorial views of an optical authentication apparatus in or ad~acent a magnetic swiping channel.
FIG. 12 is a diagrammatic view of a bar code reader.

Description of the Preferred Embcdiments Referring to FIG. 1, holographic display element 12 is positioned on a substrate base, for example, a credit card 10. Display element 12 is a rainbow hologram with an image 14 embossed as an interference pattern in a polymeric film. The image, which may be of most any form, has a three-dimensional appearance. Display element 12 has a window 18 which is cut out of the display, and a sym~ol with regions of different light reflective properties, ~uch as 212~323 bar code symbol 20, i8 printed in this vindow. The combination of display element 12 and bar code ~ymbol 20 ~s covered by transparent lamination cover 16.
In the embodiment in FIG. 2, credit card 10 includes display element 22 with image 24. Bar code sym~ol 30 i8 positioned next to display element 22. The image and bar code are covered together with transparent lamination cover 26. With this arrangement of bar code symbol and dl~play element, there i8 no need to cut the polymeric film forming the holographic display element.
FIG. 3 shows a display element 32 with image 34 and a bar code 40 which has been printed directly on top of the polymeric fil~ of the holographic display, and positioned on a box 11. The bar code could be printed on a specially lS prepared area reserved for a bar code, or even directly on top of the holographic region of the polymeric film. The bar code 40 could also be etched or embossed in the polymeric film, rather than printed. In this case, the density of the etching or embossing should be lower than that of the holographic process so that the information carried by the barcode could be easily separated.
These embodiments have several advantages. The holographic display element can be mass produced and stamped onto a credit card, or on some other ob~ect, such as a product container, at relatively low cost. The bar code symbol can be added easily, and can include individual information specific to each card or product. A
conventional flying spot scanner can be used to read the bar code symbol without interference from the holographic process, and the bar code symbol does not interfere with the holographic display element.
Referring to FIG. 4, a bar code is holographically recorded on the holographic display along with another ob~ect. Two re~Qrences, R1 and R2, and two corresponding signals, Sl and S2, are represented in the recording stago of forming a hologram 48. To holographically record S1, re~erence bean R1 i8 directed at holographic material of holoqra~ ~8. When reconstructed, R1 is again directed at the hologram and the image Sl i~ reconstructed. Two ob~ects, corresponding to Sl and S2, can both be holographically recorded separately or at the same time.
Either Sl or S2 can be reconstructed, depending on which reference, Rl or R2, is directed at the hologram. Thus S2 can represent some image, such as an eagle, and Sl a bar code symbol, or vice versa.
The bar code symbol can be recorded like another rainbow hologram, i.e. near the surface and visible in vhite light, or embossed on the polymeric film. Alternatively, the bar code could be recorded so that it is only detectable when a particular reference beam is directed toward the display, while another image on the display is recorded to be visible in white light. This approach, however, would require different recording techniques and may make the hologram more difficult to manufacture or replicate.
Referring to FIG. 4A, hologram 48 includes a holographic bar code made from reference source 74 and signal source 76 illuminating at bar code 72. To reconstruct, a reference beam from reference source 74 is directed at the hologram and the reconstructed beam i8 received by a detection apparatus at 80 or 82 if the substrate i8 transparent. If a CCD camera is used at detection position 80, preceded by relay lens 78, a virtual image can be detected. The virtual image appears a8 i~ it were at the previous location of bar code 72. If a real image i~ desired, it can be observed by a CCD camera at detection position 82. The detection apparatus, whether 212~323 receiving a real or virtual image, also includes appropriate circuitry 83 or 84 ~or electro-optically converting the information received at the CCD camera to a series of electrical signals which are decoded and converted to 5 characters.
Freguently, identification cards, such as credit cards, have a magnetic information strip which is read by being swiped through a channel that includes a magnetic reading apparatus. Referring to FIG. 5, an optical reader is positioned within a magnetic swiper channel with magnetic - reading apparatus represented generally at 51. Card 52 is shown between two sides of swiper 50. An illumination source 54 directs a beam or series of beams 55 at a holographic record in the form of a reflective strip (not shown) alongside the strip or possibly superimposed over the strip. The reflected beams 57 are received by CCD array detector 56, and information is converted to electrical signals by circuitry 58. Other optical elements, such as lenses (not shown), could also be included.
A side view of the apparatus of FIG. 5 is shown in FIG. 6 (not drawn to scale), which shows card 52 in the swiper channel with side walls ~0. Card 52 has optically readable symbol 90 and magnetic stripe 92. Within the side 50 is an optical detector 94 and magnetic information detector 96. As this figure indicates, both sets of infor~ation can be positioned on the card with a compatible reading apparatus for reading both optically and magnetically encoded data. The readers could also be in different walls, so that the optically readable information can be on one side of the card, and magnetic on the other since many credit cards have holographic displays and magnetic stripes on reverse sides of the card.
Alternatively, the optical reader could be mounted on top of ~12S32~
.
_ 9 _ the swipQr thus increasing the height of sidewalls 50. Thi8 ~ystem could be used ~ith a non-holographic ~ar code symbol or with ~ holographically produced bar code symbol used to provide added information or to authenticate the display.
S FIG. 7 shows a side view of a credit card 53 with gratlngs 60 (not drawn to scale). Using a 8imilar apparatus as that ~hown in FIG. 5, these gratings will produce reflected bursts of light which can be read in a manner similar to a bar-type code, i.e. a sequence of zeros and ones corresponding to dark and light as represented at 62.
If qratings are used, a motorized swiper can be used to direct the card at a constant rate, or a separate parallel set of equally spaced gratings for synchronization purposes can be added which also produce bursts. Either option would improve the reading since the location and length of each burst i8 important.
FIGS. 8-11 show a holographic authentication system 110. Referring to FIG. 8, the authentication system includes an illumination source 112, preferably a laser diode or a light emitting diode, which is positioned to direct a beam of light to credit card 114, which includes holographic display element 116. Reflected beam 118 is focused by lens 120, and results in signal beam 122, which is thus directed to holographic record 12 6.
Holographic record 126 has been prepared in advance with a reference beam 124, represented in phantom, and fro~
a signal beam produced from a holographic display element which was known to be authentic or valid. Holograms are often used to reconstruct a ~ignal beam by directing the reference beam at the hologram. In this case, however, signal beam 122 is used in an attempt to reconstruct reference beam 124. Beam 128, which is the reconstruction of the reference beam actually produced by directing signal 212~323 ke~ 122 at the record 126, i~ e8sentially a beam that carrie~ the correlation o~ th~ two 5ignal8. Thi8 ~ea~ i~
focused by len~ 130 onto CCD array sensor 134. The light distribution received by sensor 134 is evaluated by detection circuitry 136, which determines from the presence o~ a strong signal whether the pattern indicates an authentic display and outputs a result represented at 137.
If signal beam 122 i8 sufficiently similar to the signal used to record holographic record 126, i.e., if the di~play element is authentic, then the reconstructed reference beam 128 will essentially be the original reference bea~ 124 used to record the holographic record multiplied by the correlation between the stored and observed targets. Furthermore, a location point 132 can be identified where the reconstruction of the reference beam would be expected. FIGS. 9A and 9B illustrate light distribution patterns that arise at CCD array sensor 134 for authentic and non-authentic elements, respectively. A sharp peak in the light distribution pattern at point 132, as shown in FIG. 9A, indicates a strong correlation between the ~eam 122 used in recording the hologram and that used as the read-out. Referring to FIG. 9B, a light distribution pattern which lacks a significant peak at point 132 indicates poor cross-correlation between t~e ob~ect and the reconstruction beams. In this case, the signal beam 122 reflected from holographic display element 116 is unacceptably different from the signal beam used to maXe holographic record 126, and therefore the display element is considered non-authentic.
Referring to FIG. 10 (not drawn to scale), information card 114 includes holographic display element 116 and magnetic stripe 140 which includes individual cardholder and other information. A magnetic reading apparatus 142 reads the magnetic information when card 11 i8 swiped through swipQr ch~nnel 146. Optic~l authentication appar~tus 10 (FIG. 8) is also positioned in the swiper channel to authenticate the hologram during the S ~ame swiping action.
FIG. 11 shows a similar apparatus to that in FIG. 10 except that the authentication apparatus 110 is positioned over the sidewalls 150 of the channel, rather than within one sidewall. The authentication apparatus 10 could also be a stand-alone system, and not incorporated in another device.
The hologram authentication features of the embodiments of FIGS. 8-11 can be combined with features of the embodiments of FIGS. 1-7.
Bar code readers of the general type shown in FIG.
12 could be adapted to read bar code sym~ols incorporated into holographic displays, and to incorporate the above-described hologram authentication apparatus.
FIG. 12 illustrates a typical exemplary embodiment of a bar code reader unit 200 implemented as a gun shaped device, having a pistol-grip type of handle 253. A movable manually actuated trigger switch 254 is employed to allow the user to activate the light beam 251 and detector circuitry, typically after the time when the user has positioned the device to point at the symbol to be read. A
lightweight plastic housing 255 contains the laser light source 246, the detector 258, the optics and signal processing circuitry and the CPU 240, as well as a power source or battery 262. A light-transmissive window 256 in the front end of the housing 255 allows the outgoing light beam 251 to exit and the incoming reflected light 252 to enter. The reader 200 is designed to be aimed at a bar code symbol by the user from a position in which the reader 200 .

i~ spaced from the 8ymbol, i.~-, not touching the 8ymbol or moving across the 8ymbol. Typically, this type of hand-held bar code reader is specified to operate in the range of perhaps several inches or even further.
The reader 200 may also function as a portable computer terminal, and in such embodiments includes a keyboard 248 and a display 249, such as described in U.S.
Patent No. 4,409,470.
As further depicted in FIG. 12, a suitable lens 257 (or multiple lens system) may be used to focus the scanned beam into a scanning spot at an appropriate reference plane.
A light source 246 such as a semiconductor laser diode i8 positioned to introduce a light beam into the axis of the lens 257, and the beam passes through a partially-silvered mirror 247 and other lenses or beam-shaping structure as needed. The beam is reflected from an oscillating mirror 259 which is coupled to a scanning motor 260 ~hich is energized when the trigger 254 is pulled. If the light produced by the source 246 is marginally visible, an aiming light may be included in the optical system. The aiming light if needed, produces a visible-light spot which may be fixed, or scanned just like the laser beam; the user employ~
this visible light to aim the reader unit at the symbol before pulling the trigger.
Other embodiments of the invention are within the scope of the--following claims.
What is claimed is:
-

Claims

1. An identification element capable of being read automatically by reading apparatus, said element comprising:
a substrate; and a series of holographic gratings formed in said substrate, one surface of said substrate being exposed for viewing by said reading apparatus, said holographic gratings being formed and positioned so that a holographic recording can be viewed from said one surface of said substrate by said reading apparatus, and said gratings being formed so that a bar code symbol is holographically recorded in said holographic recording.

2. The holographic element of claim 1 wherein said element is positioned on an information card, said card comprising a substrate base with front and back surfaces, said holographic element being applied to a portion of at least one surface of said base.

3. The element of claim 1 or 2 wherein said element is a rainbow hologram, and said symbol is holographically recorded in said rainbow hologram so that it is visible to the eye in white light.

4. The element of claim 1 or 2 wherein said symbol is holographically recorded so that said symbol is not visible to the eye and can only be reconstructed with an appropriate reference beam.

5. The element of claim 1 or 2 wherein said bar code symbol comprises a series of gratings, wherein the gratings and space between said gratings reflect light differently.

6. The element of claim 2 wherein said information card further comprises an additional holographically recorded image other than said bar code symbol.

7. A bar code reader for reading a bar code symbol holographically recorded in a holgraphic element on a substrate base, said apparatus comprising:
a structure sized and configured to receive said substrate base;
an illumination source mounted with respect to said structure and positioned to direct light at said holographic element; and a detector mounted with respect to said structure and positioned to receive a holographic reconstruction of said symbol;
said detector including an optical sensor for receiving optical information from said reconstruction and converting said optical information into electrical signals.

8. The apparatus of claim 7 wherein said detector is positioned to receive a virtual image of said symbol, and said apparatus further includes at least one optical element for directing said virtual image to said detector.

9. The apparatus of claim 8 wherein said optical optical element comprises a relay lens.

10. The apparatus of claim 7 wherein said detector is positioned to receive a real image of said symbol.

11. The apparatus of claim 8 or 10 wherein said optical sensor comprises a CCD array.

12. A holographic identification element, said element comprising:
a substrate; and a series of holographic gratings formed in said substrate, one surface of said substrate being exposed for viewing, said holographic gratings being formed and positioned so that a holographic recording of an image having a three-dimensional appearance can be viewed from said one surface of said substrate, and a bar code symbol applied to said surface and in close proximity to said holographic gratings.

13. The element of claim 12 wherein said substrate is a portion of an identification card.

14. The element of claim 12 or 13 wherein said holographic display element is of the type known as a rainbow hologram.

15. The element of claim 14 wherein said rainbow hologram comprises interference patterns embossed in a polymeric film, and wherein said embossed film is adhered to said substrate.

16. The element of claim 12 or 13 wherein said bar code symbol is positioned in a window region surrounded by said display element, said window region not including holographic film.

17. The element of claim 12 or 13 wherein said display element and said bar code symbol are covered by a single transparent cover.

18. The element of claim 12 wherein said substrate is a product container.

19. Apparatus for reading a bar code symbol on an information card which includes a magnetic information stripe of the type readable by swiping the card through a channel which includes a magnetic reading apparatus, wherein the channel has a bottom surface and two walls for guiding the card, said apparatus comprising:
a structure sized and configured to receive said information card;
an illumination source mounted with respect to said structure and positioned to direct light at said symbol when said card is in said channel; and a detector positioned to receive optical information from the reflection of said illumination source from said symbol on said card, said illumination source and said detector positioned so that said magnetic information and said optical information can be read by a single swipe of said card through said channel.