EP0159828A1

EP0159828A1 - High security engraved identification card and method of making the same

Info

Publication number: EP0159828A1
Application number: EP85302160A
Authority: EP
Inventors: Barry C. Phelps
Original assignee: Computer Identification Systems Inc
Current assignee: Computer Identification Systems Inc
Priority date: 1984-03-30
Filing date: 1985-03-28
Publication date: 1985-10-30
Also published as: JPS6116897A; IN163734B; KR850006674A; IL74716A0

Abstract

A method for making an engraved identification card comprises: sputter depositing a first metallic layer (12) onto a planar surface of an electrically non-conductive substrate (14); and forming an image by engraving parallel grooves through said metallic layer into said substrate with a tapering stylus and varying the depth of the groove to thereby vary the width of the metal covered surface between adjacent grooves.

Description

Background of the Invention

The present invention relates generally to the field of machine engraved identification cards and is more particularly directed to engraved identification cards on which information and images are inscribed by engraving through one or more thin layers into an underlying substrate which is either transparent or of a contrasting color.
Engraved cards of the type contemplated by the present invention are made by applying at least one very thin layer of material to the surface of a substrate layer which is preferably transparent or translucent (herein translucent) but may be opaque and engraving through the thin surface layer into the substrate along regularly spaced parallel lines with a stylus of tapering cross-section, such as a conical stylus. As the stylus cuts into, and at preselected regions, through the surface layer and into the substrate, surface layer material is removed, exposing various areas of the substrate. By varying the depth of the cut of the tapering stylus, the width of the remaining surface layer in the region between adjacent groove lines can be continuously varied along each line. The lines and their spacing are made sufficiently fine so that the limited resolution of the human eye effects a blending of the surface color and the exposed substrate color. Information and images can thus be engraved in an identification card which is difficult to alter or duplicate. Identification cards of this type and methods of making the same have been disclosed by Oka, et al. in U.S. Patents 3,897,964 and 3,930,924.
Engraved identity cards made by existing processes typically include a relatively thick substrate sheet made of a clear or colored polymer resin onto which is applied a relatively thick surface layer having a color contrasting with that of the substrate material. Conventionally, the surface layer is formed by coating the substrate with a colored ink or liquid resin which is dried by application of heat and pressure to form a thin colored layer pressed into the surface of the substrate and fused therewith. The colored surface layer has also been obtained by laminating one or more resin plys to the substrate surface by application of heat and pressure in order to obtain intimate bonding. The laminate is then engraved by means of precision engraving machines designed for this purpose and known in the art. Briefly, the engraving machine scans an image, e.g., a facial photograph identifying the intended user of the card, and electromechanically translates the image into engraved lines wherein the depth of the engraving stylus is controlled in accordance with the image being scanned.
While the card materials presently in use provide a relatively high degree of security, as compared to non-engraved cards, alteration or forgery of conventional engraved cards is still not beyond the reach of a skilled and motivated forger. A continuing need therefore exists for engraved identification cards having enhanced forgery and tamper resistance.

Summary of the Invention

The present invention overcomes these and other shortcomings of the prior art by applying one or more discrete, very thin layers of selected metals or metallic alloys to a planar surface of a non-conductive substrate, which is preferably translucent, to obtain the blank card material which is then engraved by existing methods and equipment.
The metallic layers are applied to the non-conductive substrate by sputter deposition techniques and are preferably very thin. Sputter coating of materials is a known process whereby a target of the particular metal to be deposited is subjected to atomic bombardment in a vacuum. The bombardment causes single atoms to be ejected from the target in great numbers. A thin, uniform coating of the ejected metal atoms can be deposited onto a substrate material placed nearby. The thickness of the metallic coating can be accurately regulated and can be no more than a few atoms thick so as to be virtually transparent to light. A further benefit available through sputter deposition techniques is the abillty to deposit almost any desired metal or combination of metals onto the substrate. Unusual metallic alloys can be easily created during the sputter coating process by simply providing separate targets of each component metal which when bombarded eject atoms which combine in the deposited layers. The alloying of the different metals occurs as part of the sputter deposition process and does not require separate additional steps.
Sputter coating technology is known and commercially practiced to make, among other things, solar reflecting films of the type commonly applied to window glass for energy management purposes. However, the unique advantages attainable by application of such coating technology to the manufacture of high security engraved identification cards have not been understood and exploited until now.
The use of thin metallic coatings on engraved identity cards is inherently more secure against alteration or counterfeiting than the presently used and readily available colored inks or liquid resins. Inks and the like are a medium with which expert forgers are well acquainted. By constrast, the intimate bonding of very thin metallic layers to a plastic or equivalent substrate is not readily achieved without access to sophisticated and costly equipment coupled with considerable know-how in a somewhat esoteric technology.
One unique aspect of cards according to the invention is that the metal layer or layers deposited can be made sufficiently thin so as to be at least partially transparent. Such an effect is known with solar films. If that thin and hence transparent metal layer is deposited on a translucent substrate, an image formed by engraving through the thin metallic layer into the translucent base will be viewable as an engraved image from either the engraved side of the card or the back side of the card.
Still another unique aspect of the present invention when one or more very thin layers are deposited on the substrate is that the portion of the layer which is engraved with an image will assume a color which is different from the color of the non-engraved portion of the deposited layer depending on the angle of the line of sight at which the card is viewed. Indeed, it has been found that if viewed from an angle which is more or less perpendicular to the inwardly slanted portions of the grooves the color of the image will substantially disappear while the color of the remaining non-engraved portion of the card having the thin layer will remain unchanged. Hence, the color of the engraved portion of the card will either change or substantially disappear when compared with the color of the non-engraved portion of the card having the deposited metal layer. This effect is particularly apparent when the substrate is a transparent substrate.
Hence the unique two-sided image with sufficient contrast provided by the thin layer to make the image viewable from either the front or back of the card as well as the color attenuation and alteration of the image depending on the angle of viewing of the card relative to the color of the non-engraved portion of the deposited metal layer provides unique aspects to the present invention not heretofore available in prior art identification cards.
The use of metallic, electrically conductive coatings also permit the objective testing of authenticity of any particular card by measuring conductivity, resistivity or the light attenuation of the metallic coating. Resistivity, conductivity and light attenuation various depending on the metal coating deposited. Measurements of the conductivity, resistivity or light attenuation, which is unique for each metal or alloy coating, can be made easily and quickly with low cost, commonly available, pocket sized instruments to reliably determine the authenticity of a card made according to the present disclosure. No such objective, readily carried out authenticity test ancillary to visual inspection is avilable for engraved cards made according to presently known methods.
Additionally, sputter deposited layers can be given unusual,-difficult to duplicate appearance by judicious selection of the coating materials and by applying multiple metallic layers, each layer having a distinct coloring. When the card is engraved, the sloping side walls of the generally V-shaped groove cut by the engraving stylus will show exposed edges of the differently colored layers, lending a unique, distinctive appearance to the engraved image.
These and still other advantages available by application of sputter coating techniques to the manufacture of engraved identity cards will become apparent from the following detailed description of the preferred embodiments taken together with the attached drawings.

Brief Description of the Drawings.

Figure 1 is a top plan view of a typical identity card made according to the present invention.
Figure 2 is a fragmentary cross-section taken across the lines of an engraved card consisting of a single metallic layer sputter deposited onto a substrate.
Figure 3 is a cross-section similar to that of Figure 2 illustrating a second embodiment wherein two metallic layers are sputter deposited onto the substrate.
Figure 4 illlustrates a third embodiment wherein two sputter deposited metallic layers are spaced apart by an intermediate, non-sputter deposited layer of material.
Figure 5 illustrates a fourth embodiment wherein two sputter deposited metallic layers are applied to the planar surface of a substrate, and a very thin, substantially transparent sputter deposited electrically conductive layer is sandwiched between two sheets of substrate material.

Detailed Description of the Preferred Embodiments

With reference to the drawings, Figure 1 illustrates a typical, generally rectangular identity card 10 which has a substrate 14 on which has been sputter deposited a metallic layer 12. An area 18 of the metal coating 12 has been engraved by the already described process, exposing the substrate 14 to define printed identification data 16 and an image 18 of the authorized card bearer.
Turning to Figure 2, the cross-section of a card such as shown in Figure 1 comprises a relatively thick (e.g., .3 to 30 mils or more thick) substrate layer 14 of an electrically non-conductive material such as a polymer resin or the like and a relatively thin (10 to 3000 Angstroms thick) metallic layer 12. A number of parallel grooves 20 are engraved through the thin metallic layer 12 into the substrate 14 with a tapering stylus as has been described, leaving typically V-shaped grooves of varying depths. As may be appreciated from the drawings, the surface areas 22 between adjacent grooves 20 vary in inverse proportion to the depth of the grooves. The substrate material 14 and the metallic layer 12 are chosen to contrast sufficiently so that the areas 22 are easily visible against the sloping substrate surfaces 24 exposed by the grooving process.
Authenticity of the card may be verified by measurement of resistivity or conductivity taken between two points of any continuous metal coated area on the card. Metal coated areas may be left along the edges of a typical card as in Figure 1, towards this end.
In this respect, sputter coating technology offers a still further advantage in that the resulting metallic layers are of substantially uniform thickness. The characteristic resistivity or conductivity of the metal coating will be determined by the selection of the metal or metals applied. Resistance of the metal layer taken between any two points of the layer will depend not only on the resistivity of the conductor material but also upon the conductor cross-section, i.e., will depend and vary with the thickness of the metallic layer. This provides the possibility of introducing a second variable into the authentication test if resistance is measured and therefore increases the sensitivity of the testing. This follows from the fact that even if a counterfeiter could apply the identical metal or metal alloy to the substrate and thus duplicate a particular visual appearance it would not suffice that the material is identical, but it would have to be applied to the precise thickness before the forged document would pass the resistance test. The feasibility of implementing such testing depends, of course, on the ability on the part of the manufacturer to closely control the thickness of the applied metallic coatings. This ability is provided by sputter deposition technology.
Turning now to Figure 3 a second embodiment of the invention is shown wherein the substrate 14 which may be a sheet of clear or opaque plastic resin is coated with a first metallic sputter deposited layer 12b and a second sputter deposited metallic layer 12a directly overlying the metallic layer 12b. The two metallic layers are desirably selected for contrasting color, e.g., white, silver and black germanium. When such laminate material is grooved with a tapering stylus the slanting groove walls 24 show exposed edges of the metallic layers 12a and 12b. If these layers are made very thin, the limited resolution of the human eye will tend to blend the edge lines and colors together to yield in the perception of an observer a color which is a blend of the colors of the two metals forming layers 12a and 12b. Unusual colors can thus be obtained by selection of different metals or alloys for the two layers which, in combination with the metallic appearance of the coating, produces an unusual visual effect which is difficult to duplicate using non-metallic materials or even a single metallic layer alone.
Furthermore, the color of the image engraved on the card will change and even substantially disappear with the image becomming, for example, a black and white image, depending on the angle at which the image engraved on the card is observed by an observer. Hence, the engraving process results in a variation of the color between the non-engraved portion of the metal layer and the engraved portion. Such color variations would be exceedingly difficult, if not impossible, to duplicate, thereby greatly increasing the security of the present card when compared to prior art cards.
The use of two juxtaposed metallic layers as shown in Figure 3 does not affect the validity of the resistance testing for authenticity but rather makes the card more difficult to duplicate because the resistance measured will be a value dependent on the individual resistivities of the two metallic layers which tend to act as parallel connected resistances.
Figure 4 illustrates a third embodiment of the invention wherein a spacer layer 14b of electrically non-conductive material has been interposed between sputter deposited metallic layers 12d and 12c. The structure of Figure 4 may be constructed, for example, by sputter depositing metal layer 12d onto an electrical non-conducting substrate 14a, laminating layer 14b to the sputter deposited coating 12d by means of adhesive or other suitable means and then sputter depositing the second metallic layer 12c onto the spacer layer 14b. The laminate is then ready for engraving. The exposed edges of the metal layers 12d and 12c visible on the sloping walls 24 of the grooves 20 are spaced apart by the layer 14a and if the thickness of the spacer layer 14b is sufficient it will prevent visual blending of the exposed metal edges, lending a distinctive appearance of depth and possibly three-dimensionality to the engraved image. Different effects of color and depth may be achieved by varying the thickness of the spacer layer 14b as well as varying the relative and absolute thicknesses of the sputter deposited metallic layers. Varying visual effects affecting a difference in the color between the observed engraved image and the color of the non-engraved portions of the thin metal layer will also be created in such an identification card.
The spacer layer 14b may be the same color and material as the underlying substrate 14a. The appearance of the engraved card may be further varied and forgery thereof thus further deterred by making the layers 14a and 14b opaque or transparent in different combinations. For example, layer 14b may be of transparent, either clear or color tinted resin material, while the underlying substrate 14a may be an opaque material of any color. In the embodiment of Figure 4, the two conductive layers are insulated from each other by the electrically non-conductive spacer layer 14b. Each of the two conductive layers 12b and 12c may thus be individually subjected to restivity, conductivity or resistance testing thereby to even more conclusively establish authenticity of the identity document.
Figure 5 illustrates a fourth embodiment of the invention wherein two metallic layers 12e and 12f are sputter deposited onto a substrate in a manner similar to that of Figure 3. The embodiment of Figure 5 differs from that of Figure 3 in that a further metallic electrically conductive layer 20/is interleaved between two substrate sheets 14a and 14b. Desirably, the conductive sputter deposited layer 201 is positioned within the substrate at a level below the maximum penetration of the grooving stylus to thereby preserve the integrity of the layer 201during the image forming process. The layer 201, if made sufficiently thin, will not be readily visible to someone not aware of its existence and may be used to check authenticity of the card by subjecting the layer 20lto the aforementioned resistance testing. The presence of the layer 20tmay be further hidden by making the layer sufficiently thin so that it is substantially transparent or translucent to light, and also making one or both of the substrate layers 14a and 14b similarly transparent. Layer 201, under these conditions will not be readily visually apparent. The making of virtually transparent metallic layers is again readily achievable through sputter deposition technology.
Counterfeiting of engraved cards of this type may be further deterred or exposed by selecting unusual metallic alloys characterized by uncommon resistivity, conductivity and light attenuation properties for one or more of the sputter deposited metallic layers. In spite of the ease with which such rare metallic combinations are achievable through sputter deposition, the same metallic compositions would be extremely difficult to duplicate precisely by someone not having access to sophisticated equipment. Even where a counterfeiter has access to such sophisticated equipment, the precise metallic composition forming the layers would be difficult to duplicate without knowing the individual metals so deposited and the amount of such metals deposited. This information could be readily kept secret and would be unique for each company or entity which distributed or otherwise sponsored the particular identification card.
It is thus apparent that the novel application of sputter deposition technology to the manufacture of engraved identity cards not only simplifies the manufacture of such documents and reduces their cost, but at the same time substantially increases the resistance of the cards to forgery and alteration by providing a fast and simple objective test of authenticity by measuring resistivity, conductivity, resistance, or light attenuation characteristics of the sputter deposited metallic layers, by enabling the deposition of very thin difficult to duplicate, metal layers, and by providing a wide range of easily obtainable unusual metallic colorings and appearances through combination of metallic materials.
Any of the embodiments shown in Figures 2 through 5 or yet other variations of the illustrated embodiments which will be apparent to those skilled in the art, may also include a thin layer (e.g., 2 mils thick) clear or tinted transparent plastic or equivalent material covering the uppermost metal layer, the images being engraved through this top layer as well as the underlying metallic layers. This not only increases the complexity of the card, thus also increasing the difficulty of duplicating the same, but by using a color tinted transparent top layer, the tint combines with the coloring of the underlying sputter deposited metal to create images of unusual appearance. The objective of seeking very unusual coloring of the materials or unusual color combinations of the various card layers is to create an identity document which is highly distinctive in appearance while at the same time difficult to duplicate.
Access to the metallic layers for purposes of resistance testing may be had a variety of ways in any of the disclosed embodiments. If the metallic layer is not covered by non-conductive layers, the resistivity test may be conducted by merely applying a pair of electrodes to the exposed metal layer. In the event that non-conductive layers are used to cover the conductive layers, access thereto may be still had in a variety of ways. For example, fine sharp electrode needles may be used to puncture through the non-conductive covering to thereby make electrical contact with the metal layer. In the alternative, access to the metal layer may be had at the edge of the card by means of suitably constructed electrodes. As yet another alternative, access windows or openings may be provided in the non-conductive covering to permit electrode contact with the metal layer.
While particular embodiments of the present invention have been described and illustrated, it will be understood that many changes are possible to the described embodiments without departing from the spirit and scope of the present invention which is limited only by the scope of the following claims.

Claims

1. A method for making an engraved identification card comprising:

sputter depositing a first metallic layer onto a planar surface of an electrically non-conductive substrate; and

forming an image by engraving parallel grooves through said metallic layer into said substrate with a tapering stylus and varying the depth of the groove to thereby vary the width of the metal covered surface between adjacent grooves.

2. The method of claim 1 further comprising the steps of sputter depositing a second metallic layer onto said first metallic layer prior to forming said image, said first and second metallic layers being of metals selected for dissimilar visual appearance such that contrasting edges of the metallic layers are exposed by the engraving process.

3. The method of claim 2 wherein said first and second metallic layers are made sufficiently thin so that the limited resolution of the human eye is unable to resolve the two layers and the perceived color is a blend of the colors of the individual metallic layers.

4. The method of claim 2 further comprising the step of appplying a spacer layer of non-metallic material between said first and second sputter deosited metallic layers to thereby impart a characteristic appearance to the engraved image.

5. The method of any one of claims 1, 2, 3 or 4 further comprising the step of interleaving a sputter deposited electrically conductive metallic layer between layers of substrate material.

6. The method of claim 5 wherein said interleaved conductive layer is disposed at a depth greater than the maximum penetration of the engraving stylus during said image forming process to thereby preserve the integrity of the interleaved layer.

7. The method of claim 5 wherein said interleaved layer is substantially transparent or translucent to light thereby to make visual detection of said interleaved layer difficult.

8. The method of claim 7 wherein the substrate layer between said interleaved layer and said first metallic layer is substantially transparent.

9. The method of claim 7 wherein the substrate material underlying said interleaved layer is opaque to light.

10. The method of any one of claims 2, 3, or 4 further comprising the step of sputter depositing a third or still further metallic layers onto said second layer prior to said image forming step.

ll. The method of any one of claims 1, 2, 3, or 4 further comprising the step of applying a relatively thin layer of non-conductive transparent material over said first metallic layer prior to said image forming steps.

12. The method of claim 11 wherein said thin layer of transparent material is color tinted to thereby obtain an unusual appearance of the engraved image.

13. An engraved identification card comprising:

a first metallic layer sputter deposited onto a planar surface of an electrically non-conductive substrate; and

an image formed by parallel grooves through said metallic layer into said substtate, said grooves having sloping side walls and varying in depth to thereby vary the width of the metal covered surface between adjacent grooves.

14. The card of claim 13 further comprising a second metallic layer deposited onto said first metallic layer, said first and second metallic layers being of metals selected for dissimilar visual appearance such that contrasting edges of the metallic layers are visible on said sloping side walls.

15. The card of claim 14 wherein said first and second metallic layers are sufficiently thin so that the limited resolution of the human eye is unabel to resolve the two layers and the perceived color is a blend of the colors of the individual metallic layers.

16. The card of claim 14 further comprising a spacer layer of non-metallic material between said first and second sputter deposited metallic layers to thereby a characteristic appearance to the engraved image.

17. The card of any one of claims 13, 14, 15 or 16 further comprising an electrically conductive metallic layer interleaved between layers of substrate material.

18. The card of claim 17 wherein said interleaved conductive layer is disposed at a depth greater than the maximum penetration of the engraving stylus during said image forming process to thereby preserve the integrity of the interleaved layer.

19. The card of claim 17 wherein said interleaved layer is substantially transparent or translucent to light thereby to make detection of said interleaved layer difficult.

20. The card of claim 19 wherein the substrate layer between said interleaved layer and said first metallic layer is substantially transparent.

21. The method of claim 19 wherein the substrate material underlying said interleaved layer is opaque to light.

22. The card of any one of claims 14, 15 or 16 further comprising a third or still further metallic layer deposited onto said second layer to provide more than two layer edges visible on said slanting side walls.

23. The card of any one of claims 13, 14, 15 or 16 further comprising a relatively thin layer of non-conductive transparent material over said first metallic layer.

24. The card of claim 23 wherein said thin layer of transparent material is color tinted.