HK1079597B - Laser engraving methods and compositions, and articles having laser engraving thereon - Google Patents

Description

Laser inscription method and composition and laser inscription-bearing article

Data of related applications

This application is related to U.S. patent application 09/747,735 filed on 12/22/2000, U.S. patent application 09/602,313 filed on 6/23/2000, U.S. patent application 10/094,593 filed on 3/6/2002, U.S. provisional patent application 60/358,321 filed on 2/19/2002, and U.S. patent 6,066,594.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from the following U.S. provisional patent applications:

● use laser-imprinted material sensitization (application No. 60/344,677; attorney docket No. P0503-inventor Brian Labrec), filed 24/12/2001;

● laser inscription coating system (application No. 60/344,675; attorney docket No. P0515-inventor Brian Labrec), filed 24/12/2001; and

● variable information is formed on identification documents by laser ablation (application No. 60/344,676; attorney docket No. P0516-inventor Brian Labrec)

Technical Field

The present invention relates generally to laser marking or inscription methods and compositions containing one or more laser-enhancing additives, and methods for delivering information, images, and security features on data carriers by laser inscription and marking, including laser inscription and marking using those compositions described above.

Background

Identification documents (hereinafter "ID documents") play an extremely important role in modern society, and an example of ID documents is identification cards (i.e., ID cards). Identification documents are used in everyday life to prove identity, verify age, enter a particular area, prove driving permission, and redeem checks, among other things. Passengers are required to present ID documents at check-in, security check-in and before boarding the aircraft at airports. Further, since it is in a society where cash exchange is increasingly unnecessary, ID documents can be used at the time of payment, use of automatic teller machines, debit and credit, and the like.

Many types of identification and identification documents, such as driver's licenses, national identification cards, bank cards, credit cards, controlled access cards and smart cards, have certain information about the bearer. Such information includes name, address, date of birth, signature, photograph, etc.; in addition, the cards or certificates may carry other variable data (i.e. data specific to a particular card or certificate, such as an employee number) and non-variable data (i.e. data common to most cards, such as an employer name). These cards referred to above are hereinafter generally referred to as "ID documents".

In producing images useful in the field of identifying documents, it is often necessary to include document (such as ID cards, drivers licenses, passports, and the like) data, a representative indicia of the document issuer (e.g., the name or logo of a official seal, or company or educational institution), and data or representative indicia of the document holder (e.g., a photograph, name, or address). Typically, a pattern, logo or other overt, representative indicia of the issuing party of the document can be used to prove the authenticity, authenticity or effective issuance of the document. The camera or other data or the personal identification of the holder enables the holder to be assured of rights and priority in using certain devices in conducting commercial transactions and activities.

Identification documents such as ID cards having printed background security patterns, logos and personal identification data for holding pedestrians have appeared and are described in, for example, the following patents, us 3,758,970, issued to m.annenberg on 9/18/1973; british patent 1,472,581, issued to g.a.o.gesellschaft FurAutomation Und organization mbH, 3/10 of 1976; international patent application PCT/GB82/00150, published 25/11.1982, publication No. WO 82/04149; U.S. Pat. No. 4,653,775, issued to t.rapael et al on 3/31/1987; U.S. patent 4,738,949, entitled g.s.sethi et al, 4 months and 19 days 1988; and U.S. patent 5,261,987 issued to j.w. luening et al, 11/16/1993.

The advent of commercial machinery (printers) for producing dye images has made it easier to convert the electronic data obtained by the camera into colour pictures, and such printers produce colour pictures by the principle of thermal transfer. Generally, this is done using color filters or other known means to obtain digital image information (electronic signals) of the original color. These signals are then used to print an image on the data carrier. For example, such information can be printed using a printer having a plurality of small heating elements (e.g., pins) for imagewise heating each of a series of donor sheets (carrying sublimating cyan, magenta, and yellow dyes, respectively) associated with an image receiving element (which may be, for example, a substrate). The foregoing thermal dye transfer methods are described in several patents, for example, U.S. Pat. No. 4,621,271, issued to s.brown on month 11 and 4 of 1986; U.S. patent No. 5,024,989 issued to y.h. chiang et al, 6/18/1991.

There are two main types of commercial systems that issue ID documents, namely the so-called "central" issue (CI) and the so-called "on-the-spot" or "over-the-counter" (OTC) issue.

CI-type ID documents are not immediately provided to the holder, but are provided to the holder at a later time from a central location. For example, in a CI-type environment, the bearer reports data to a data collection station, which is forwarded to the card manufacturer, and finally the card is forwarded to the bearer, typically by mail. As another example, a driver may receive a driver's license posted by a CI manufacturer in a short time after passing a driving test, and the holder may transmit related data through the internet.

Centrally issued identification documents can be manufactured from digitally stored information and typically comprise an opaque central material (also referred to as a "substrate"), such as paper or plastic, sandwiched between two transparent sheets of plastic, such as polyester, to protect the aforementioned information from abrasion, exposure to the elements and tampering. These materials used in CI-type identification documents are durable. In addition, CI-type identification documents often provide a higher level of security than OTC-type identification documents because they provide the ability to prepress security features such as "microprints," uv security features, security markings, and other features that are now unique to CI-type identification documents on CI-type identification documents. Another security advantage of CI-type documents is that the security features and/or the material used to make those features are centrally located, which reduces the likelihood of loss or theft (relative to those security materials that are distributed in large numbers over "on the spot" locations).

In addition, a CI assembly process is performed in a centralized facility, one after the other, such a facility can produce thousands of cards in a continuous manner. For this reason, CI type is more efficient than OTC type because OTC type is produced intermittently. Thus, if mass produced, the price per CI-type ID document will be lower.

OTC-type identification documents are issued a little more quickly to the bearer at the document issuing station than CI-type identification documents. The OTC assembly process can provide identification documents on-site. (an example of an OTC assembly process is the automotive department environment, where driver's licenses are issued to individuals on the spot after a successful pass through an examination). In some cases, the inherent nature of the OTC assembly process has led to the advent of small, sometimes compact, print assemblies for printing ID documents.

There are many forms of OTC-type identification documents that are possible due to differences in price and desirable characteristics. Some OTC ID documents contain highly plastic polyvinyl chloride (PVC) or composite structures having a polyvinyl chloride film laminated to polyester in the range of 0.5-2.0 mils (13-51.mu.m), which provides a suitable receptor layer for the photo-assembled thermal transfer dye and has any variable or non-variable data required to identify the bearer. These data can then be protected to varying degrees by transparent, thin (0.125-0.250 mils, 3-6.mu.m), overlaminate sheets applied to the print head and holographic thermal stamp sheet, or by transparent polyester sheets (0.5-10 mils, 13-254.mu.m) used to carry the usual security features, two different types of protective sheets sometimes also being applied at laminating stations separate from the print head. As to which type of protective sheet is selected, it is necessary to depend on durability and safety.

FIGS. 1 and 2 are front and cross-sectional views (portion above line AA in FIG. 1) respectively of a prior art ID document 10. In fig. 1, the prior art ID document 1 comprises a photograph 12, a bar code 14 (which may contain information specific to the person whose image appears in the holder of the photograph 12 and/or the same information for each ID document), variable personal information 16, such as an address, signature and/or date of birth, and physiological information 18 (e.g. a fingerprint) of the person whose image appears in the photograph 12. Although not illustrated in FIG. 1, the ID document 10 can include a magnetic strip (e.g., it can be on the back side (not shown) of the ID document 10) and various security features, such as a security device (e.g., a tightly printed device containing both particle printed and unprinted areas, which are in close proximity to each other, such as a fine line printed security device used in the printing of currency papers, securities, and similar articles).

Referring to FIG. 2, the ID document 10 includes a preprinted center 20 (e.g., white PVC material, for example) having a thickness of about 25 mils, the center 20 being laminated with a transparent material such as clear PVC22 having a thickness of about 1-5 mils. The composition forms a so-called "card space" 25 having a thickness of about 30 mils, and the messages 26a-c are printed in the card space 25 by a process such as dye diffusion thermal transfer (abbreviated as D2T2) printing (see, for further details, U.S. patent 6,066,594). The information 26a-c may, for example, include a label, such as non-variable information common to a large number of identification documents, such as the name and logo of the issuer of the document. The messages 26a-c may be formed by any process that can attach indicia to the particular center material used.

To protect the printed messages 26a-c, an additional layer of ultrathin sheet 24 is attached to card blank 25 and prints 26a-c using, for example, 1 mil adhesive (not shown). The ultrathin sheet 24 is substantially transparent. Those skilled in the art of making identification documents are aware of materials suitable for forming such protective layers and conventional materials may be used provided they have sufficient transparency. Examples of suitable materials for making the ultrathin sheet include biaxially oriented polyester or other light transparent durable plastic films.

The printing techniques described above are not the only methods used to print data onto a carrier such as an ID document. Laser beams, for example, can be used to mark, write, bar code, and imprint many different types of materials, including plastics. Lasers have been used, for example, to mark plastic materials to create a mark such as bar codes, date codes, semicolons, stop codes, and company logos. It is recognized that laser marking or marking typically involves a process of marking identification marks, characters, text, tactile text, including text, patterns, designs (such as decorative or security features), photographs, and the like, on documents.

One way of laser marking thermoplastic materials is to irradiate the material, such as a thermoplastic material, with a laser at a given irradiation location. The laser-irradiated areas absorb the energy of the laser and thereby generate heat, which induces visible discoloration in the thermoplastic material. This visible color change serves the role of a "logo" or indicator; it will be appreciated that the laser beam may be controlled so as to form a pattern of "marks" that can constitute images, lines, numbers, letters, patterns and the like. Depending on the type of laser beam and the type of material used, different types of markings are also produced (e.g. dark markings against a bright background, bright markings against a dark background, and colored markings). Some types of thermoplastic materials, such as polyvinyl chloride (PVC), Acrylonitrile Butadiene Styrene (ABS), and polyethylene terephthalate (PET), are capable of absorbing laser energy in their natural state. Some materials that are transparent to laser energy in their virgin state, such as polyethylene, may require the addition of one or more additives thereto that are responsive to laser energy.

For additional background, different laser marking and/or imprinting techniques are disclosed in several patents, for example, U.S. Pat. nos. 6,022,905, 5,298,922, 5,294,774, 5,215,864, and 4,732,410. In addition, different applications of printing information using lasers are also described in U.S. Pat. nos. 4,816,372, 4,894,110, 5,005,872, 5,977,514 and 6,179,338.

Summary of The Invention

Writing or imprinting information onto an ID card using a laser beam has many advantages over conventional printing. For example, foaming of thermoplastic materials, which can be carried out together with certain types of laser engraving, can be used to provide tactile markings, which are a strong proof of data carriers, which are difficult to counterfeit and alter. In addition, laser engraving generally does not require the use of ink, and therefore can reduce the cost of manufacturing consumer products for ID cards. Laser engraving is also more durable than ink printing and is less prone to wear (it is particularly useful if the counterfeiter wants to "erase" the indicia on the ID card). The resolution and print quality of laser inscription is generally higher than that of conventional ink-based printing. Laser engraving is a more environmentally friendly manufacturing process than ink printing, especially since laser engraving does not use some of the solvents and chemicals commonly used to manufacture inks.

Despite the above advantages of laser lithography, certain limitations remain. Even when using known laser-enhancing additives, laser marking of some types of materials does not produce sufficient contrast for all applications. Some types of materials, such as silicon filled polyolefins (silicon filedpolyleins), TESLIN center ID documents using traditional ultra-thin sheet materials, and TESLIN composite structures (TESLIN is commercially available from PPG Industrial, inc. Also, in certain manufacturing environments, laser imprinting may require a significant amount of time and/or too much laser energy, even with known laser additives.

The inventors of the present application have discovered that the laser-inscription performance of certain types of materials, including materials that are not readily laser-inscriptable (such as TESLIN center ID documents), can be improved by methods that enhance the sensitivity of sheets containing such materials to laser radiation and/or enhance the sensitivity of coatings applied to such materials to laser radiation.

One inventive technique disclosed herein can improve the performance of laser marking or laser inscription of materials by adding the inventive laser enhancing additive to the material. These materials may be sheets, coatings or articles having sheets or coatings formed thereon. These additives make the material more sensitive to laser light, greatly improving its ability to laser-imprint a sheet ID document. In some embodiments, these additives can improve laser engraving performance even in those structures that tend to be more easily laser engraved (e.g., fused polycarbonate card structures, polyvinyl chloride (PVC), polyethylene terephthalate (PET), and Acrylonitrile Butadiene Styrene (ABS)).

The inventors have found that by using the above-described additive of the present invention, the processing time can be shortened for the polycarbonate ID card structure. In addition, laser scribing can be accomplished with less laser energy and/or lower levels of laser energy than known methods using the laser-enhancing additives described herein. Another technique of the invention disclosed herein improves the light sensitivity of laser-inscribed materials by applying to those materials a coating that contains at least one laser-enhancing additive as described below. Such material may be part of any type of article that is intended to be laser marked or laser marked. For example, in one embodiment, the material is a central layer in the identification document.

In one embodiment, the additive for enhancing laser marking ability comprises a potassium copper iodide (CuKI)₃) Or copper iodide (CuI) with at least one selected from zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates (e.g., RSO)₂Na or R-OSO₂Na) and thioesters (e.g., a-SH containing species). Such additives may be added to a foil layer (which itself may be laser imprinted or marked) and/or a coating layer (the surface to be coated is also laser imprinted or marked).

In one embodiment, it is also an advantage that the additive comprises effective amounts of copper potassium iodide and zinc sulfide in the host material. The primary material may be, for example, a sheet or a coating. The host material may also be a material that is later added to the sheet or coating. The host material may be, for example, a thermoplastic or thermoset.

For flakes, the host material (and the flakes to which the host material may be added) may generally be any material whose laser inscription performance is improved by the addition of the laser-enhancing additive described herein, and it is expected that many materials developed in the future will be able to use the additive described herein. In at least one embodiment, the addition of the laser-enhancing additive described herein to the sheet enables laser imprinting of a gray scale image on the sheet.

For coatings, in one embodiment, the additive comprises effective amounts of copper potassium iodide and zinc sulfide in a liquid carrier material, which together form a coating that can be applied to an article to be laser engraved. The liquid carrier material may be any of the materials known to be useful as coatings, including resin, polyester, polycarbonate, vinyl, acrylate, urethane and cellulose-based coatings. In one embodiment, the liquid carrier material is a material that is used to coat the surface of a center material (e.g., TESLIN and polycarbonate) in an identification document. The coated surface is typically a material (including flakes): laser imprinting performance is improved by the addition of a coating containing the laser-enhancing additive described herein. In at least one embodiment, the surface is provided with the ability to imprint a gray scale image thereon by adding the additive of the present invention to the coating.

For transparent sheets and/or coatings, the effective amount of the laser-enhancing additive varies with the tolerance at which the transparency of the sheet or coating may be reduced. In one embodiment, for transparent flakes or coatings, the effective amount of this additive varies from 0.001 wt% to 0.1 wt% (based on the total weight of the material to which the additive is added).

For non-transparent flakes and/or coatings (e.g., colored coatings, colored flakes, and/or opaque flakes), an effective amount of this additive can be greater than 1 wt% (e.g., 1 wt% to 100 wt%). Those of ordinary skill in the art will recognize that the effective amount of such additives for a given application will depend on a number of factors, including the properties of the sheet or coating, the type of laser marking (e.g., gray scale or non-gray scale) used, the type of laser used, and the desired properties or characteristics of the article or surface being marked, among others. Advantageously, the effective amount of this additive is about 0.06% by weight for at least some of the transparent sheets and/or coatings used to make up the identification document.

In another advantageous embodiment, the components of the additive may be present in two different layers through which the laser beam can pass. In one embodiment, potassium copper iodide may be present in a first layer of the sheet and zinc sulfide may be present in a second layer of the sheet, where the first and second layers are either immediately adjacent or separated by one or more layers of material (e.g., another layer of sheet or an adhesive) that is transparent to laser radiation. The combined action of copper potassium iodide and zinc sulfide causes laser engraving to occur in one or both of the two layers when the laser beam is directed such that it passes through both layers. In another embodiment, an effective amount of copper potassium iodide may be present in a coating applied to the article, and an effective amount of zinc sulfide may be present in a sheet applied to the coating.

In another aspect, the present invention provides a composition having laser-marking properties comprising a host material and an effective amount of a laser-enhancing additive. The laser enhancing additive comprises a first amount of copper potassium iodide (CuKI)₃) Or copper iodide (CuI), and a second amount of at least one substance selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters. In one embodiment, the first amount and the second amount are the same (e.g., 1 part cuprous iodide and 1 part barium sulfide). In one embodiment, the first amount and the second amount are different (e.g., 3 parts copper potassium iodide to 1 part zinc sulfide, or 2 parts cuprous iodide to 4 parts thioester). In one embodiment, the composition can be excimer laser, Nd: YAG and CO₂At least one of laser light (including optical pumping and diode pumping Nd: YAG laser).

In one embodiment, the laser enhancing additive is present in the composition in an amount of about 0.001 wt% to about 0.100 wt% based on the total weight of the composition. In one embodiment, the laser enhancing additive is present in an amount of from 0.1 wt% to 100 wt% based on the total weight of the composition. In one embodiment, the laser enhancing additive is present in an amount of about 0.06 wt% based on the total weight of the composition. In one embodiment, the laser enhancing additive comprises 0.03 wt% of potassium copper iodide (CuKI) based on the total weight of the composition₃) Or copper iodide (CuI), and 0.03 wt% of at least one of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonate, and thioester, based on the total weight of the composition.

In one embodiment, the host material of the composition is a material that is not sensitive and/or opaque to laser radiation, such as a material that cannot itself be laser imprinted with an acceptable gray scale image. The primary material may be a sheet or a coating. For example, the host material may comprise at least one of the following materials: thermoset materials, thermoplastic materials, polymers, copolymers, polycarbonates, fused polycarbonates, polyesters, amorphous polyesters, polyolefins, silicon-filled polyolefins, TESLIN, foamed polypropylene films, polyvinyl chloride, polyethylene, thermoplastic resins, engineering thermoplastics, polyurethanes, polyamides, polystyrene, expanded polypropylene, Acrylonitrile Butadiene Styrene (ABS), ABS/PC, high impact polystyrene, polyethylene terephthalate (PET), PET-G, PET-F, polybutylene terephthalate (PBT), acetal copolymers (POM), Polyetherimides (PEI), polyacrylates, poly (4-vinylpyridine), poly (vinyl acetate), polyacrylonitrile, polymeric liquid crystal resins, polysulfones, polyether nitrides and polycaprolactones and mixtures thereof.

In at least one embodiment, the present invention also provides an article (e.g., an identification document) capable of gray scale image laser engraving comprising a central layer, a first layer, and a second layer. The core layer has a first surface. The first layer comprises a first host material comprising an effective amount of a composition comprising potassium copper iodide (CuKI)₃) Or at least one of copper iodide (CuI). The second layer comprises a second host material and is associated with the first host material such that a single laser beam can penetrate at least a portion of the first layer and at least a portion of the second layer. The second host material comprises an effective amount of a second laser-enhancing additive selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters. The first and second layers are operatively coupled to each other, and at least one of the first and second layers is operatively coupled to the first surface of the central layer. In one embodiment, a gray scale image may be laser imprinted into at least one of the first and second layers.

In one embodiment, the first layer is substantially transparent and the first laser enhancing additive is present in an amount of 0.001 wt% to 0.100 wt% based on the total weight of the first host material. In one embodiment, the second layer is substantially transparent and the second laser enhancing additive is present in an amount of 0.001 wt% to 0.100 wt% based on the total weight of the second host material. In one embodiment, the third layer is interposed between the first layer and the second layer; the third layer comprises a material in which a laser beam can propagate.

In another aspect, the present invention provides a method of marking a material by subjecting the material to laser radiation. An effective amount of a laser-enhancing additive is added to the material. The laser enhancing additive comprises copper potassium iodide (CuKI)₃) Or copper iodide (CuI), and at least one selected from zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters. The material is exposed to laser radiation in a manner that enables the material to be imprinted by the laser radiation. In one embodiment, an effective amount of such laser-enhancing additive comprises 0.01 wt% to 0.1 wt%, e.g., 0.06 wt%, of the material. In one embodiment, an effective amount of such laser-enhancing additive comprises 0.1 wt% to 100 wt% of the material. In one embodiment, the mark may be formed in gray scale in at least a portion of the material by exposing the portion to laser radiation. In one embodiment, the laser imprinted material is used in the manufacture of identification documents.

In another embodiment, the present invention provides a method of laser imprinting a gray scale image on an article having a first layer and a second layer. A first effective amount of copper potassium iodide (CuKI)₃) Or at least one of copper iodide (CuI) is added to the first layer. A second effective amount of at least one substance selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters is added to the second layer. One laser beam, e.g. one from Nd: Yag laser or CO₂At least one of the lasers is directed such that it can pass through at least a portion of the first layer and at least a portion of the second layer, thereby forming a gray scale image in at least one of the first and second layers. In one embodiment, the beam of laser light is directed such that it can pass through at least part of the first layer and at least part of the second layer, the first layer and the second layer thus being bonded to each other.

In at least one embodiment, the present invention provides a multilayer comprising a core layer and a film layerThe document is identified. The thin film layer covers at least a portion of the core layer and is bonded to a portion of the core layer. The film layer contains an additive comprising an effective amount of potassium copper iodide (CuKI)₃) Or copper iodide (CuI), and an effective amount of at least one material selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters. In one embodiment, the identification document carries a first marking, and the marking is obtainable by irradiating the film layer with a laser beam. In one embodiment, the indicia comprises at least one of a gray scale image, a photograph, text, tactile text, graphics, information, a security pattern, a security indicia, and a digital watermark.

In another aspect, the invention provides an identification document having improved laser inscription performance. The identification document comprises a TESLIN center coated with a coating comprising the laser enhancing additive described above. A gray scale image representing variable data (e.g., personalized data) is laser imprinted onto the TESLIN center with a Nd: Yag laser. Optionally, a foil can be attached to the TESLIN either before or after laser engraving. If this sheet is applied before TESLIN center laser printing, this sheet is usually transparent to laser radiation.

Although some companies provide laser-imprinted document materials, these materials can be expensive. At least some embodiments of the invention may overcome at least some of these and other limitations in the prior art. At least some embodiments of the present invention provide an inexpensive laser inscription that improves gray scale inscription and is easy to manufacture without lacking the required security features.

The foregoing and other features and advantages of the invention will be apparent from the following detailed description, taken in conjunction with the accompanying drawings.

Brief description of the drawings

Advantages, features and aspects of embodiments of the present invention will be more fully understood from the detailed description and the accompanying drawings that follow. Wherein:

FIG. 1 is a schematic view of a prior art identification document;

FIG. 2 is a schematic cross-sectional view of the prior art identification document of FIG. 1 along line AA;

FIG. 3 is a schematic cross-sectional view of an identification document according to a first embodiment of the first aspect of the invention;

FIG. 4 is a schematic cross-sectional view of an identification document according to a second embodiment of the first aspect of the invention;

FIG. 5 is a schematic cross-sectional view of an identification document according to a third embodiment of the first aspect of the invention;

FIG. 6 is a schematic cross-sectional view of an identification document according to a fourth embodiment of the first aspect of the invention;

FIG. 7 is a schematic cross-sectional view of an identification document according to a first embodiment of the second aspect of the invention;

FIG. 8 is a schematic cross-sectional view of an identification document according to a second embodiment of the second aspect of the invention;

the drawings are not necessarily to scale, emphasis generally being placed upon illustrating the principles of the invention. Moreover, in the figures, like numerals represent like elements. Also, with the present application, laser imprinted indicia, information, identification documents and data, etc. may be displayed in a particular cross-sectional shape (e.g., rectangular), but this is by way of example and illustration only, and not by way of limitation, nor does this shape represent the actual cross-sectional shape in laser imprinting or production of identification documents.

Detailed Description

A. Introduction and definition

In the foregoing discussion, the term "ID document" is used broadly and includes at least all types of ID documents, including, but not limited to, documents, discs, credit cards, bank cards, phone cards, stored value cards, prepaid cards, smart cards (e.g., cards that include a plurality of semiconductor chips such as memory devices, microprocessors, and microcontrollers), contact cards, contactless cards, proximity cards (e.g., Radio Frequency (RFID) cards), passports, drivers 'licenses, network access cards, employee badges, debit cards, security cards, visas, immigration certificates, national ID cards, social security cards and badges, licenses, identification cards or certificates, voter registration and/or identification cards, police station ID cards, transit cards, loyalty cards and certificates, gun licenses, badges, gift certificates or cards, gift certificates or badges, labels, CD's, consumer goods, and/or personal digital certificates, Buttons, keypads, electronic components, etc., or any other suitable items or articles that can record information, images, and/or other data relating to the functions and/or targets or other entities for authentication.

It is noted that for the purposes of this disclosure, the terms "certificate," "card," "badge" and "document" may be used interchangeably.

In addition, in the foregoing discussion, "identification" includes, but is not limited to, information, decoration, and any other purpose that may be carried on an article in its original, partially manufactured, and final state. Also, in addition to ID certification, the techniques of the present invention have application to product labels, product packaging, business cards, packages, charts, maps, logos, and the like, particularly those articles that include laser-engraved sheet and ultrathin sheet structures. The term ID certificate is thus broadly defined herein to include such labels, packaging, cards and the like.

As used herein, "personalization," "personalization data," and "variable data" are used interchangeably to refer to at least those data, images, and information that are printed upon personalization of the card. The personalization data may, for example, be "personal" or "specific" to a particular cardholder or group of cardholders. The personalization data may include information unique to a particular card-holder (such as biometric information and image information), but is not limited to unique data. The personalization data includes data such as date of birth, height, weight, eye color, address, etc. that is personal to a particular card holder, but not necessarily unique to that holder (e.g., other cards may also have the same personal data such as date of birth). However, depending on the application, the personalization data may also include some type of data that is not different between different cards, but is still provided at the time of card personalization. For example, in identification documents that are laser engraved at the time of card personalization, the official seal laser engraved onto a portion of the ultrathin sheet is in some cases considered "personalized" information.

The terms "laser-inscription" and "laser marking" may be used interchangeably herein.

The term "indicia" as used herein refers not only to signs for human reading, but also to signs for machine reading. Such indicia need not be visible to the human eye, particularly when used for machine reading, but may be in the form of visible indicia only upon infrared, ultraviolet or other non-visible radiation. Thus, in at least some embodiments of the invention, the indicia formed on any one of the layers (e.g., the central layer) of the identification document may be in the form of a visible marking, either partially or wholly, only upon non-visible radiation. For example, indicia containing a visible "virtual" image superimposed on an invisible "real" image for machine reading may also be used.

"sheeting" and "overlaminate" include, but are not limited to, film and sheet products. Flakes useful in at least some embodiments of the present invention include those comprising a substantially transparent polymer and/or a substantially transparent adhesive, or those having a substantially transparent polymer and/or adhesive as part of their structure, such as an extruded feature. Applicable foils comprise at least polyester, polycarbonate, polystyrene, cellulose ester, polyolefin, polysulfone or polyamide. Amorphous or biaxially oriented polymers may also be used to form the sheet. The foil contains a plurality of foil layers spaced apart from one another, for example, a boundary layer and/or a film layer.

The transparency of the sheet may, for example, be determined by the information contained in the identification document, the particular color and/or security features used, etc. While in some embodiments it is preferred that the foil layer have a thickness of 1 mil to 20 mils, its thickness is not critical. Any one of the web layers can be laminated to any other layer of the material (e.g., the central layer) using any conventional lamination method known to those of ordinary skill in the art of the production of articles such as identification documents. Of course, the types and configurations of flakes described herein are merely exemplary, and many different types of flakes are suitable for use in the present invention, as will be appreciated by those of ordinary skill in the art.

For example, in ID documents, the sheet can provide a protective covering for the printed substrate and to some extent prevent tampering with the document (e.g., the sheet must be removed to alter the printed information and then replaced after the alteration). Various lamination processes are described in assignee's U.S. patents 5,783,024, 6,007,660, 6,066,594, 6,159,327. Other lamination methods are disclosed in, for example, U.S. patents 6,283,188 and 6,003,581.

The material from which the sheet is made may be transparent, but is not required to be transparent. The sheet may comprise a synthetic resin impregnated or coated base material composed of successive layers of material bonded together by heat, pressure and/or adhesive. The sheeting also includes security sheeting, such as clear sheeting having security process features and procedures, which is not subject to counterfeiting, alteration of data, replacement of photographs, copying (including color photocopying), and simulation with readily available materials and techniques. The sheet may also comprise a thermosetting material, such as an epoxy material.

For purposes of illustration, the discussion that follows proceeds with the structure of ID documents (e.g., TESLIN centers and multi-layer ID documents) and fused polycarbonate structures. However, it is to be understood that the invention is not so limited. Indeed, as will be appreciated by those skilled in the art, the techniques of the present invention can be applied to many other structures formed by many different methods to improve their laser inscription performance. In general, the process of the present invention is applicable to any product that can be laser engraved, particularly those used to imprint gray scale images. For example, the present invention may be applied to any product that is intended to be laser marked or marked, particularly those that can be marked with gray scale images. For example, in at least some embodiments, the present invention can be applied to any product that is intended to be laser-imprinted, particularly articles to which sheets and/or coatings are applied, including articles made of paper, wood, cardboard, paperboard, glass, metal, plastic, textiles, ceramics, rubber, and many man-made materials, such as microporous materials, single phase materials, two phase materials, coated paper, synthetic paper (e.g., TYVEC, manufactured by Dupont Corp of Wilmingto, Delaware), foamed polypropylene films (including calcium carbonate foamed polypropylene films), polyolefins, polyesters, polyethylene terephthalate (PET), PET-G, PET-F, and polyvinyl chloride (PVC), and combinations thereof.

In addition, at least one embodiment of the present invention is directed to virtually any article that is laminated or at least partially covered with a material that is not sufficiently responsive to laser radiation to form a desired marking (e.g., a gray scale image) thereon, but is more readily responsive to a laser beam, at least to an extent sufficient to form the desired marking on its surface with the laser beam, by the addition of the laser-enhancing additive of the present invention to this material or another material (e.g., a coating or sheet) substantially adjacent to this material.

B. Laser engraving

It is necessary to mark text, information, graphics, logos, security marks, security features, logos, images or photographs onto certain parts of a structure such as a multilayer structure (including after lamination) and ID documents. It would be beneficial if techniques were available to produce patterns and pictures with some or all of these characteristics, particularly gray scale and/or color, using laser engraving.

However, in some cases, portions of a multi-layer ID document structure (e.g., a structure comprising polyester and polycarbonate sheets in the center, such as TESLIN) may be nonconductive for acceptable imprinting of specific types of information. For example, some substances may be laser marked (using, for example, CO)₂Laser) produces textual information (e.g., dark colored on bright objects), but is not satisfactorily imprinted with gray scale information (e.g., gray scale information conveying up to 256 shades of gray), such as images and photographs, or full color map information.

Other materials are difficult to imprint even with lasers. For example, certain materials, such as silicon-filled polyolefins, TESLIN, polycarbonate, fused polycarbonate, polyethylene, polypropylene (PPRO), polystyrene, polyolefins, and copolymers are not very sensitive to laser radiation, and thus they are not easily laser-inscribed. The search for laser-imprinted structures comprising non-sensitive and non-conductive materials can sometimes also provide the ability to laser-imprint structures that do not appear to be useful for transmitting information (although such imprinting may help provide tactile feel to such structures). Such multilayer structures lack the sensitivity to facilitate laser engraving. The ability to provide a gray scale image on an identification document using a laser according to the present invention may be beneficial because it provides an increased sense of security to such identification documents. In addition to this, it is possible with the present invention to add additional security features, such as digital watermarks, to the laser-imprinted grey-scale image.

First aspect of the invention

C.1 characteristics

In a first aspect, an embodiment of the present invention includes photosensitive processing of at least one of the layers of a multilayer structure, such as at least one lamina, to help overcome the problem of the layered material failing to respond to laser inscription and/or lacking the ability to laser inscription of a gray scale image thereon due to an inadequate response. We have found that: the performance of laser scribing can be improved while reducing scribing time by using one or more of the above described methods of the present invention to pass the sensitivity of the ultrathin section. In one practical application of this embodiment, a sheet can be modified by adding an effective amount of one or more laser-sensitive additives to the sheet material. We have also found that the laser-sensitive additives described herein can be separated into two or more layers, which can improve the performance of laser inscription. Also (as mentioned in the second and third aspects of the invention) we have found that these laser-sensitive additives also improve the performance of laser-inscription if they are present in a coating applied to the material to be engraved.

At least one embodiment of the first aspect of the present invention is based on the surprising discovery that the laser imprinting process of materials such as flakes can be improved and enhanced by adding to the flakes a first effective amount of a first composition which is potassium copper iodide (CuKI)₃) Or copper iodide plus a second effective amount of a second composition that is at least one of: zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates (e.g., RSO)₂Na or R-OSO₂Na) and thioesters (e.g., substances containing-SH). CuI or CuKI₃The combination with at least one of ZnS, BaS, alkyl sulfate, thioester is hereinafter referred to as "laser-enhancing additive of the present invention". The laser enhancing additive of the present invention comprises a composition comprising copper potassium iodide (CuKI)₃) Or copper iodide (CuI), and a composition comprising zinc sulfide (ZnS), barium sulfide (BaS), an alkyl sulfonate (e.g., RSO)₂Na or R-OSO₂Na) and thioesters, sometimes referred to as "laser-enhancing additives of the invention".

As will be appreciated by those skilled in the art, the effective amounts of the first and second compositions will vary depending on the materials to which the laser enhancing additive of the present invention is added and the laser engraving process to be used. In at least one embodiment, the laser-enhancing additive of the present invention comprises equal amounts of the first and second compositions. In at least one embodiment, the laser-enhancing additive of the present invention includes a second composition in an amount greater than the amount of the first composition. In at least one embodiment, the laser-enhancing additive of the present invention comprises a first composition in an amount greater than a second composition.

The exact nature of the mechanism of action of the laser-enhancing additives of the present invention has not yet been established. The laser-enhancing additive of the present invention may enhance the molecular activity within the sheet when heat is applied in the laser, resulting in a faster and/or stronger response of the sheet to the laser energy. The laser-enhancing additive of the present invention may also increase the opacity of the sheet to improve its response to laser energy. It is also possible to generate black species within the host material by a response between the various components of the laser-enhancing additive of the present invention and/or between it and the host material.

By using the laser enhancing additive of the invention, the imprinted article can be modified by adding the laser enhancing additive of the invention to a host material (or coating the material with a coating containing the laser enhancing additive of the invention, as will be discussed in relation to the second aspect of the invention) to form high quality patterns and other imprints on the article, such as a multilayer ID document, at acceptable production speeds. The laser-reinforcing additive can not only enhance the sensitivity of materials insensitive to laser, but also shorten the imprinting time. In addition, because the laser-enhancing additives of the present invention can improve the responsiveness of the material being engraved to laser energy, high resolution patterns, such as gray scale images (which can be used to identify documents), can be formed during the laser engraving process.

In at least one embodiment, the use of the laser-enhancing additive formulation described above improves the performance of laser imprinting by increasing the contrast (including at least dark colors against a bright background) that occurs when a laser of a given power level is used. In at least some embodiments, this enhanced contrast of the pattern due to the use of one of the laser-enhancing additives described above enables the laser-inscription work to be performed using a lower energy laser, while a higher energy laser is required if this laser-enhancing additive is not used. In at least some embodiments, the enhanced sensitivity due to the use of one of the laser-enhancing additives described above can reduce the time to complete the imprinting.

In accordance with at least some examples of the first aspect of the present invention, any of the laser-enhancing additives described above may be added to virtually any material (including all thermosets and thermosets) to enhance the process of laser marking and/or laser inscription of a substance to which the laser-enhancing additive of the present invention is added or any substance sufficiently close thereto. Advantageously, the addition of the laser-enhancing additive of the present invention allows all materials to which it is added to be laser-imprinted with gray scale images.

According to another embodiment of the first aspect of the invention, the first portion of the laser-enhancing additive of the invention (i.e., comprising an effective amount of CuI or CuKI)₃A portion of) can be added to the first sheet and a second portion of the laser-enhancing additive of the invention (i.e., a portion containing an effective amount of at least one of ZnS, BaS, alkyl sulfonates, and thioesters) can be added to the second sheet, and a single laser can pass through both sheets and laser inscription of either or both of the layers can be performed. According to another embodiment of the first aspect of the invention, the laser enhancing additive of the invention can be added to a core material laminated with a material transparent to laser radiation, wherein the core material is also possibly laser inscribed.

In at least one advantageous embodiment, the laser-enhancing additives of the present invention are added to center, sheet and/or ultra-sheet materials used in the manufacture of identification documents to improve the laser inscription or marking process of the identification document and the laser inscription of gray scale images onto the identification document.

The laser-enhancing additives of the present invention are useful for both those materials that are generally insensitive to laser radiation and those materials that are sensitive to laser radiation. The laser-enhancing additives of the present invention can be present in a material such as a sheet and/or in a separate layer of material with other compositions such as other laser-enhancing or absorbing additives, reinforcing fillers, antioxidants, flame retardants, stabilizers, plasticizers, lubricants, dispersants, and the like.

Illustrative examples of sheet materials to which the laser reinforcing additives of the present invention may be added include, but are not limited to, polyesters, Polycarbonates (PC), fused polycarbonates, polyvinyl chloride (PVC), polyethylene, thermosets, thermoplastics, thermoplastic resins (including resins that foam when heated), Engineering Thermoplastics (ETP), polyurethanes, polyamides, expanded polypropylene (EPP), polypropylene, acrylonitrile-butadiene-styrene (ABS), ABS/PC products, High Impact Polystyrene (HIPS), polyethylene terephthalate (PET), PET-G, PET-F, polybutylene terephthalate (PBT), acetal copolymers (POM), and Polyetherimides (PEI), polymers, copolymers, polyesters, amorphous polyesters, polyolefins, silicon-filled polyolefins, polyethylene terephthalate (PET), and polyethylene terephthalate (PEI), and the like, TESLIN, foamed polypropylene film, polystyrene, polyacrylate, poly (4-vinylpyridine), poly (vinyl acetate), polyacrylonitrile, polymeric liquid crystal resins, polysulfones, polyether nitrides and polycaprolactone, as well as any known plastic or polymer. It will of course be appreciated that embodiments of the invention can be applied to laser marking and/or laser marking of plastics materials to produce many different articles made by any known method, including moulding and extrusion.

In at least some embodiments, the total concentration of the laser-enhancing additive of the present invention in the flake varies from 0.001 wt% to 0.1 wt%. In at least some embodiments, the laser-enhancing additives of the present invention are added at greater concentrations (such as from 0.1 wt% to 100 wt%). At concentrations greater than 0.1 wt%, the laser-enhancing additives of the present invention can still be used to enhance the ability to laser mark or imprint, but may compromise some of the transparency of the laminate (if, in fact, the laminate is initially sufficiently transparent or translucent).

Advantageously, in at least one embodiment, the laser-enhancing additive comprises about 0.06 wt% of the entire sheet. In another advantageous embodiment, the 0.06 wt% comprises 0.03 wt% of CuI or CuKI₃And 0.03 wt% of at least one of ZnS, BaS, alkyl sulfonate, and thioester. Of course, as will be appreciated by those skilled in the art, other concentration ranges for the laser-enhancing formulation may be used, particularly where opaque materials are used as well as colored materials. In addition, it is also recognized that CuI or CuKI₃And at least one of ZnS, BaS, alkyl sulfonates, and thioesters may be varied.

The concentration of the laser-enhancing additive of the present invention used for a given sheet depends, at least in part, on the properties of the sheet and its end use, durability, environmental conditions to which the sheet is subjected, and the like. It may be that higher concentrations of the laser-enhancing formulation may affect one or more properties of the sheet, such as transparency, durability, flexibility, opacity, hardness, and the like. Of course, the appropriate amount of additive can be determined for a particular ultrathin sheet application without undue experimentation.

It is contemplated that the laser-enhancing additive of the present invention can be incorporated into a sheet that is attached (e.g., by adhesive, lamination, chemical reaction, etc.) to any product and enables the sheet to be laser-inscribed, particularly a gray-scale image, to produce (particularly if the sheet is substantially transparent or translucent) a laser-inscribed or marked on the sheet that is attached to the article. Thus, it is believed that the laser-enhanced sheets of the present invention can be used to make many different articles that can be laminated, including but not limited to identification documents, identification cards, credit cards, prepaid cards, phone cards, smart cards, contact cards, contactless cards, composite contact-contactless cards, proximity cards (e.g., Radio Frequency (RFID) cards), electronic components, labels, packaging, containers, building materials, construction materials, piping materials, automotive, aerospace and military products, computers, recording media, labels, tools and processing devices, medical devices, consumer goods and toys. Also, it is contemplated that the entire article of manufacture may be formed, in whole or in part, using a material containing the laser-enhancing additive of the present invention, and then laser inscribed or marked.

C.2 preparation/manufacture

The laser-enhancing additive of the present invention can be added to the flakes in a variety of ways. The techniques to be mentioned below describe the preparation of the laser-enhancing additive of the invention and the method of its addition to the flakes according to one embodiment of the first aspect of the invention. By way of example only, the technique will be described in a related embodiment in which the flakes comprise polycarbonate and the laser enhancing additive of the present invention comprises CuKI₃And ZnS, but this particular formulation should not be considered limiting.

In this example, the preparation of the laser-enhancing additive of the present invention was accomplished by using a twin screw extruder to produce a highly concentrated polymer blend (so-called "masterbatch") of the laser-enhancing additive of the present invention. By combining the desired host material (e.g., polycarbonate) with the laser-enhancing additives of the present invention (e.g., ZnS and CuKI)₃) The process of combining together can be made into a masterbatch. The host material and laser-enhancing additive of the present invention are dried prior to mixing, which reduces degradation of each component. The following are illustrative examples of the preparation of laser-enhancing additives of the present invention, which may be used in at least some embodiments of the present invention.

● the laser reinforcing additive of the invention is masterbatched with the same material (e.g., polycarbonate) as the final film material (e.g., polycarbonate) of the sheet.

● the laser reinforcing additive of the invention is masterbatched with a material (e.g., polystyrene) that is different from the final film material of the sheet (e.g., polycarbonate).

● the laser reinforcing additive of the invention is separately masterbatched with the same material (e.g., polycarbonate) as the final film material (e.g., polycarbonate) of the sheet.

● the laser-enhancing additives of the invention are separately masterbatched with a material (e.g., polystyrene) different from the final film material of the sheet (e.g., polycarbonate).

The above-described masterbatch formulation can be made to the desired concentration by forming a monolayer film using a single screw extruder. To reduce costs, a synergistic layer may be formed by extruding a photosensitive material (e.g., a material to which the laser-enhancing additive of the present invention is added) proximate to a non-photosensitive material. In one embodiment, the optimum concentration for marking and maximizing optical properties for polycarbonate is 0.06 wt%. The concentration may be adjusted up to 0.1 wt%, and if the concentration is higher than 0.1 wt%, the transparency of the transparent material may be reduced. In one embodiment, more than one of the aforementioned laser-enhancing additives of the present invention may be used as an additive (e.g., ZnS and CuKI)₃And BaS and CuI), other known laser-enhancing additives may also be combined with one or more of the foregoing laser-enhancing additives of the present invention.

Of course, as will be appreciated by those skilled in the art, the masterbatch formulations and materials of the above examples are provided as examples and are not limiting. For example, those skilled in the art will readily understand how the laser-enhancing additives of the present invention work with acrylics, acetates, polystyrenes, urethanes, polyesters (both aromatic and aliphatic), polyether nitrides, ABS, and polyvinyl chloride, as well as other aforementioned sheet materials.

C.3 exemplary embodiment

After the film is formed for sheeting, it can be used with articles for laser marking or marking by various known processing procedures. In one embodiment of an ID document for laser marking or inscription, the following is an exemplary embodiment of a method for making an ID document by using a film and/or sheet containing the laser enhancing additive of the present invention.

Figure 3 is a schematic cross-sectional view of an identification document 10 according to a first embodiment of the first aspect of the invention. In a first embodiment, an ID document 10 of the invention preferably includes a multi-layer structure, as shown in FIG. 3. Although the cross-sectional configuration and elements shown in FIG. 3 differ from the prior art, for ease of illustration, the ID document 10 has a front-out appearance that is very similar to the ID document 10 of FIG. 1. The ID document 10 includes a layer of core material 50 and at least a first sheet 52 to which the laser enhancing additive of the present invention is added (herein, the sheet to which the laser enhancing additive of the present invention is added is also referred to as "inventive sheet"). A laminate layer is preferably added to the front and back surfaces of the center to form a multi-layer structure.

In this embodiment, center 50 is a 10 mil substantially opaque white sheet center such as a TESLIN based center. Prior to lamination, the core material 50 is pre-printed to include an indicia 54A such as fixed or variable information or data. Preprinting includes screen printing, offset printing, laser or ink jet printing, flexographic printing or similar printing. "fixed" information may include non-personally related information such as department or company information, country information, and the like. Variable information, or information unique to the ID holder, can be preprinted, such as by a color laser xerographic process.

The fixed and/or variable information may also include one or more built-in security features to reduce identity spoofing. For example, in one embodiment of the invention, portions of the ID document 10, including either or both of the central material 50 and/or the sheet 52, can include a security feature, such as a security mark or security pattern. The security device may be applied in an ordered arrangement having a tightly printed pattern, for example having a large number of finely printed or unprinted areas, all in close proximity to one another. A close-printing mode, for example, appears as a frequently repeated logo or design, or a precision line-printed security design is used in the printing of banknotes, securities and the like, and may take the form of filigree decorations, guilloches or other precision line-printed patterns. Us patent 4653775 provides an example of such security printing. Laser engraving facilitated by the present invention can be used to print security markings or security patterns.

In addition, the laser inscription facilitated by the present invention can also be used to add a digital watermark to any indicia (whether conventional or laser-inscribed) that has been printed on any layer of the ID document 10. Digital watermarking is one such process: a physical or electronic medium is modified to embed a machine-readable code. The modification of such media makes the embedded code imperceptible or barely perceptible to the user, but may be discovered via an automated detection process. The code may be embedded, for example, in a photograph, text, graphics, image, substrate or sheet structure and/or a background pattern or monochrome of a photo identification document. The code may even be transmitted by uv or ir inks and dyes.

Digital watermarking systems typically have two main elements: an encoder for embedding a digital watermark in a host media signal and a decoder for detecting and reading the embedded digital watermark from an equal-check signal containing the digital watermark. By altering the host media signal, the encoder can embed a digital watermark. For purposes of illustration, if the host media signal comprises a photograph, the digital watermark may be embedded in the photograph, and the photograph with the embedded digital watermark may be printed on a photo identification document. The decoded element analyzes the parity signal to detect the presence of the digital watermark. In applications where a digital watermark encodes information (e.g., a unique identifier), a decoding component extracts the information from the detected digital watermark.

Several specific digital watermarking techniques are known. The reader is assumed to be familiar with the literature in this field. Particular techniques for embedding and detecting imperceptible watermarks in media are described in detail in, for example, Digimar's co-pending U.S. patent application 09/503,881 and U.S. patent application 6,122,403. Techniques for embedding digital watermarks in identification documents are described in more detail in, for example, Digimarc' co-pending U.S. patent application 10/094,593 filed on 6/3/2002 and U.S. patent application 10/170,223 filed on 10/6/2002, co-pending U.S. provisional patent application 60/358,321 filed on 19/2/2002, and U.S. patent 5,841,886. In addition, it should be noted that the present invention includes ID documents that contain more or less features than the illustrated ID document 10.

Referring again to FIG. 3, after printing, a core material 50 is laminated to two sides, a first sheet 52 of approximately 10 mils, the sheet 52 being photosensitive to laser radiation due to the addition of the laser-enhancing additive of the present invention. In this example, the first sheet 52 comprises ZnS and CuKI in a base sheet material such as polyester or polycarbonate₃And (3) an additive. In one application of this embodiment, the front and back first sheets 52 are bonded together with an adhesive (not shown in FIG. 3), such as a copolyester or paraffin wax containing adhesive. Other adhesives useful in embodiments of the present invention include polyester, polyester urethane, polyether urethane or polyolefin hot melt or ultraviolet or heat set adhesives. In the layering process, there are multiple layers of structures formed, during which process time, temperature and pressure need to be adjusted to optimize the laminated structure.

In at least some embodiments of the first aspect of the present invention, useful sheets include those comprising a substantially transparent polymer and/or a substantially transparent adhesive, or those having a substantially transparent polymer and/or a substantially transparent adhesive as part of their structure, such as having an extruded feature. The first sheet 52 may contain a plurality of phase separated sheet layers, such as boundary layers and/or film layers. The first sheet 52 may comprise a light clear durable plastic film such as amorphous or biaxially oriented polyester. In at least some embodiments, the sheet need not be sufficiently transparent, but may be colored or opaque, so long as a gray scale image can be laser inscribed thereon. Of course, the types and configurations of flakes described herein are provided by way of example only, and many different types of flakes may be used in the present invention, as will be appreciated by those of ordinary skill in the art.

In at least some embodiments, the first tab layer 52 can provide an additional security feature for the identification document 10. For example, first sheet 52 may include a low viscosity polymeric layer, optically variable inks, an ink printed image that is legible under infrared or ultraviolet light but invisible in normal white light, an image printed with fluorescent or phosphorescent inks, or any other security feature that may be used, which makes the document difficult to tamper or counterfeit and which does not compromise the laser inscription properties of first sheet 52.

In at least one embodiment (not shown), the first sheet comprises a pocket into which the center material 50 can be slid. With such a bag, methods such as heat, pressure, adhesives, and the like may be used to attach the center material 50 to the first sheet 52 comprising the bag. The present invention may be used with many known structures and configurations for lamination, which will be appreciated by those of ordinary skill in the art.

Referring again to fig. 3, adhesive may be applied to the first sheet 52 by methods such as solvent coating, casting, or hot melt extrusion. Such an adhesive may also be coated, cast or extruded onto the surface of the core material 50. First sheet 52 can then be heat laminated to central material 50 to form a secure bond. Additionally, some processes for attaching first sheet 52 to central material 50 include injection molding or hot melt extrusion. Virtually any known method for attaching the first sheet 52 to the center material 50 will be recognized by those skilled in the art. For example, techniques such as standard heat and pressure, pressure only, chemical dissolution by solvent mixing, Ultraviolet (UV) methods, and/or Electron Beam (EB) methods may be used to laminate the first sheet 52 to the center material 50.

When the first sheet 52 is properly attached to the central material 50, the ID document 10 can be laser imprinted. In at least one embodiment, laser engraving is used to personalize the ID document. In at least one embodiment, the usable laser for imprinting is a neodymium: yttrium aluminum garnet (Nd: YAG) laser that uses an output of 3 watts (W) (103D) and 10W (power line E) (a laser usable in at least one embodiment of the present invention is commercially available from Rofin Baasel laser of Boxborough, Massachusetts). Compared with the 3W laser, the 10W laser in the device uses a gray scale marking software. In at least one embodiment, the Nd: YAG laser emits light at a wavelength of about 1064 nanometers (nm).

Because the laser-enhancing additive of the present invention improves the response of first sheet 52 to laser light, the time required to laser scribe a given area of the sheet is reduced relative to when the laser-enhancing additive of the present invention is not used. Furthermore, the improvement in response performance also enables laser-engraving of gray-scale images on the sheet 52, such as images having up to 256-tone gray scale, especially when using Nd: YAG lasers (including lamp-pumped YAG lasers, diode-pumped Nd: YAG lasers, and optical-pumped Nd: YAG lasers). When using other types of laser, e.g. excimer laser and CO₂Lasers, the effective amount of laser-enhancing additive of the invention used and the materials to which it is added can also have similar performance enhancements in laser imprinting.

Furthermore, the use of the laser enhancing additive of the present invention also improves the laser inscription performance of so-called "vector information" in identification documents. Vector information is non-captured information (e.g., a logo) in an identification document that does not typically include so-called pixel information, which is information that is captured, such as a signature image and/or a photographic image. When the laser-enhancing additive of the present invention is added to a material to be laser-inscribed that contains vector information, the material may be sufficiently photosensitive that the vector information can be inscribed, achieving the "tactile" effect known in the laser-inscription art.

Referring again to FIG. 3, one or more indicia 54B-54F, such as variable information (e.g., date of birth, address, biometric information, etc.), are imprinted into the ultrathin layer 52 by a focused laser beam. In one embodiment, the laser used is a Nd: YAG laser, although other suitable lasers (e.g., CO) may be used₂). As previously described, the areas irradiated by the laser absorb the laser energy, generating heat that causes a color change effect visible in the first sheet 52. This visible color change serves as a "marker" or indicator. Under the action of certain flakes and a laser, heat from the laser beam causes foaming, as shown in indicia 54D. This foaming can create a raised area in the first sheet 52 that is tactile when touched. The indicia 54B-F may contain virtually any type of information, including photographs, data, images, fingerprints, and text. Although not shown in the cross-sectional view of FIG. 3, our testing shows that indicia 54B-F may comprise a suitable gray scale image (used for security purposes, such as identification or authentication). In experiments, the inventors were able to imprint a desirable gray scale photograph, non-tactile text and tactile text in the foil layer 52.

As an example, we added the laser enhancing additive of the present invention (ZnS and CuKI were used in this experiment)₃) Was compared with a commercial polycarbonate sheet produced by the Bayer Polymer Division. We imprinted a 0.75 inch by 1.0 inch photo at 750 Dots Per Inch (DPI) separately into each Bayer material and the inventive ultrathin sheet containing the inventive laser-enhancing additive. The same laser (one beam) of the same energy was used for each sampleA 3W 103D laser, as described above), we have found that to imprint a desirable photograph, Bayer material takes approximately 40 seconds. In contrast, by adjusting the frequency of the laser, the sheets to which the laser enhancing additive of the present invention is added only take up to 20 seconds.

Although the embodiment of FIG. 3 illustrates that the first sheet 52 containing the laser-enhancing additive of the present invention almost completely covers the central material 50, in at least some embodiments of the present invention, the laser-enhancing additive of the present invention may be added to one sheet, with only a portion of the sheet covering the central material 50 being composed of this sheet.

For example, FIG. 4 is a schematic cross-sectional view of an identification document according to a second embodiment of the first aspect of the invention. In the embodiment of FIG. 4, the ID document 10 is more likely to have a multi-layer structure. For ease of illustration, the ID document 10 may have a front-out appearance similar to the document 10 of FIG. 1, although the cross-section shown in FIG. 4 is not constructed and does not differ from the prior art. In the embodiment of fig. 4, a portion of a first sheet 52 containing a laser-enhancing additive of the present invention is at least partially treated in a layer of another material, such as a so-called "blank" sheet 56 (e.g., a sheet that does not contain a laser-enhancing additive of the present invention). When a laser is applied to the first sheet 52, a third mark 54G is formed. The blank sheet 56 may comprise a material that is inherently sensitive to laser radiation, or it may itself be a material that is not sensitive to laser radiation. It should be noted that the layer of other material need not even be a sheet at all, and that the first sheet 52 containing the laser-enhancing additive of the present invention is treated in such material. Thus, in some articles, the surface may include a portion or "window" of the first sheet 52 containing the laser-enhancing additive of the present invention, while the remainder of the surface is of some other material (e.g., ceramic). This configuration may be applicable, for example, in the labeling of electronic components and/or devices.

FIG. 5Is a schematic cross-sectional view of an identification document according to a third embodiment of the first aspect of the invention. In the embodiment of FIG. 5, the ID document 10 is more likely to have a multi-layer structure. For ease of illustration, the ID document 10 may have a front-out appearance similar to the document 10 of FIG. 1, although the cross-section shown in FIG. 5 is not constructed and does not differ from the prior art. In the embodiment of fig. 5, a first portion of the laser-enhancing additive of the present invention is processed in a first foil layer 52 and a second portion of the laser-enhancing additive of the present invention is processed in a second foil layer 55. In particular, in this embodiment, first foil layer 52 contains an effective amount of potassium copper iodide (CuKI)₃) Or copper iodide (CuI), and the second foil layer 55 contains an effective amount of at least one of: zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates (e.g., RSO)₂Na or R-OSO₂Na) and thioesters. The first webbing 52 and the second webbing 55 are constructed and arranged so that a laser passes through them to form indicia 66 and 64 in one or both of the first webbing 52 and the second webbing 55, respectively. As will be appreciated by those of ordinary skill in the art, whether a mark is formed in a given lamina layer depends on the particular type of laser used, the manner in which the laser is used (e.g., pumped), and the duration of application of the laser energy.

It should be understood that although the example of fig. 5 shows that the first foil layer 52 contains an effective amount of potassium copper iodide (CuKI)₃) Or copper iodide (CuI), and the second foil layer 55 contains an effective amount of at least one of: zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates (e.g., RSO)₂Na or R-OSO₂Na) and thioesters, but the position of the compounds in the respective first and second layers may be reversed. That is, the first sheet layer 52 may contain an effective amount of at least one of the following: zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates (e.g., RSO)₂Na or R-OSO₂Na) and thioesters, and the second foil layer 55 contains an effective amount of copper potassium iodide (CuKI)₃) Or cuprous iodide (CuI)) At least one of (1).

Referring again to FIG. 5, the ID document 10 also includes a layer of center material 50 (in this case, the center material layer has a thickness of 10 mils to 20 mils) with a first sheet 52 laminated on either side thereof, the center material 50 being printed on the outer surface thereof with a pre-print 70. In one embodiment, the preprint 70 is non-variable information such as organization name, logo, and the like. The printed information 72 can be printed on the first sheet layer 52 using a technique such as dye diffusion thermal transfer. The third layer 57 is a material transparent to laser radiation (e.g. a foil or an adhesive) which allows penetration of a laser beam directed at the second foil layer 55, at least locally to the first layer 52.

In at least one embodiment, the first sheet 52 may be composed of a material that is substantially more responsive to laser radiation than the second sheet 55. In this embodiment, as a laser beam passes through the second and first foil layers 55 and 52, the irradiated areas in the first foil 52 can bubble up onto the second layer 55, whereby the first foil 52, the second foil 55 and (optionally) the third layer form a bond.

In one embodiment, the ID document 10 of the embodiment of FIG. 5 is a multilayer fused polycarbonate structure that is used as an ID document. The multilayer structure more likely comprises a central and at least one top and bottom ultrathin sheet. The core material 50 may comprise filled titanium dioxide (TiO)₂) The Polycarbonate (PC) film of (a), the film typically having a whitish color. The information 70 may be pre-printed onto the center material 50 prior to melting. Examples of desirable preprinting processes include screen printing, offset printing, laser or ink jet printing, flexographic printing, and the like.

The central material 50 and the first sheet 52 are fused together to form a structure 53 that helps prevent delamination. The structure 53 in this example is a solid PC ID document 10. The adjustment of time, temperature and pressure helps to bond the first sheet 52 to the polycarbonate core material 50. The second sheet 55 may be an ultrathin sheet of material.

In one example, we compared the imprinting performance of a molten polycarbonate structure of the invention containing a titania filled polycarbonate core and containing ZnS and CuKI with a Muhlbauer polycarbonate card₃An additive of polycarbonate ultra-thin sheets. This comparison included the imprinting of a 0.75 inch by 1.0 inch photo at 750 Dots Per Inch (DPI). Similar, desirable gray scale qualities were imprinted, 20-25 seconds for Muhlbauer imprinting, whereas by adjusting the laser frequency, the molten polycarbonate structures of the present invention required only 11-15 seconds.

The laser-enhancing additives of the present invention can also be used in a sheet having one or more additional sheet layers attached thereto. For example, FIG. 6 is a schematic cross-sectional view of an identification document according to a fourth embodiment of the first aspect of the invention. In the embodiment of FIG. 6, the ID document 10 is more likely to have a multi-layer structure. For ease of illustration, the ID document 10 may have a front-out appearance similar to the document 10 of FIG. 1, although the cross-section shown in FIG. 6 is not constructed and does not differ from the prior art. In fig. 6, the ID card 10 includes a central material 50 (shown as being about 5 mils thick for illustrative purposes) that is laminated to a layer (shown as being about 5 mils thick) of a first sheet 52 to which the laser enhancing additive of the present invention is added. Overlying the first sheet 52 is a layer of a second sheet 58 (this layer is shown to be approximately 5 mils thick for ease of illustration), in this embodiment the second sheet 58 is made of a material that is not sensitive to laser radiation. In this example, the second sheet is a transparent material. The laser engraves indicia 54I-54J on first sheet 52. The overall thickness of the ID document 10 in FIG. 6 is about 30 mils, which in at least one embodiment, is such that the architecture of the ID document 10 meets and/or exceeds the standards of the American Association of Motor administrators (AAMVA) and the American national institute of standards (ANSI). The overall thickness of the ID document 10 in FIG. 6 also conforms to the International organization for standardization (ISO) specifications for identification documents, such as ID cards. It will be appreciated that many other thicknesses of sheet are suitable for use in the manufacture of ID documents which conform to one or more of the organizational requirements of AAMVA, ANSI and ISO. For example, in fig. 6, the center material 50 may be 20 mils thick, the first sheet 52 may be 2 mils thick, and the second sheet 58 may be 3 mils thick.

Although fig. 6 illustrates only a single layer of flakes on first flake 52 (with the laser enhancing additive of the present invention added), it will be recognized that as long as the laser used reaches first flake 52, then more layers will be added to first flake 52.

We have found that one or more advantages are possible with the flakes of the invention described herein. For example, gray scale images can be laser engraved or marked onto using the sheeting of the present invention. Furthermore, laser inscription or marking can be carried out more quickly with lower laser energy using the flakes of the invention. Also, laser engraving using the flakes of the present invention is durable, abrasion resistant and environmentally friendly.

C.4 further embodiments of the first aspect of the invention

It is contemplated that at least the following combinations and other similar combinations are useful embodiments of the first aspect of the invention:

1. a composition having laser-marking properties comprising:

a primary material; and

an effective amount of a laser-enhancing additive, the laser-enhancing additive comprising:

a first amount of copper potassium iodide (CuKI)₃) Or copper iodide (CuI); and

a second amount of zinc sulfide (ZnS), barium sulfide (BaS), an alkyl sulfonate (e.g., RSO)₂Na or R-OSO₂Na) and thioesters.

2.1, wherein the laser-enhancing additive is present in an amount of about 0.001 wt% to about 100 wt% based on the weight of the total composition.

3.1 wherein the host material is substantially transparent and the laser enhancing additive comprises about 0.001 wt% to about 0.1 wt% of the total composition.

4.1, wherein the laser-enhancing additive comprises about 0.06 wt% of the total composition.

The composition of claim 5.4, wherein each of the first and second amounts comprises about 0.03 wt% of the total composition.

The composition of claim 1, wherein the first amount and the second amount are the same.

7.1, wherein the first amount is greater than the second amount.

The composition of claim 1, wherein the first amount is less than the second amount.

9.1 of the composition wherein the composition is selected from the group consisting of a diode-pumped Nd: Yag laser, an optically pumped Nd: Yag laser, and CO₂The composition is laser-inscribable upon at least one of laser and excimer laser radiation.

10.8, wherein the composition can be laser engraved to form a gray scale image.

11.1 wherein the host material comprises a material which is not itself sufficiently sensitive to laser radiation but which allows laser imprinting of grey scale images into the host material.

12.1 wherein the host material comprises at least one of: thermoset materials, thermoplastic materials, polymers, copolymers, polycarbonates, melt polycarbonates, polyesters, amorphous polyesters, polyolefins, silicon filled polyolefins, TESLIN, foamed polypropylene films, polyvinyl chloride, polyethylene, thermoplastic resins, engineering thermoplastics, polyethylene, polyamides, polystyrene, expanded polypropylene, Acrylonitrile Butadiene Styrene (ABS), ABS/PC, high impact polystyrene, polyethylene terephthalate (PET), PET-G, PET-F, polybutylene terephthalate (PBT), acetal copolymers (POM), Polyetherimides (PEI), polyacrylates, poly (4-vinylpyridine), poly (vinyl acetate), polyacrylonitrile, polymeric liquid crystal resins, polysulfones, polyether nitrides, and polycaprolactone.

13. An article capable of laser-engraving a gray scale image, comprising:

a central layer having a first surface;

a first layer comprising a first host material, the first host material comprising an effective amount of a first laser enhancing additive comprising copper potassium iodide (CuKI)₃) Or copper iodide (CuI); and

a second layer comprising a second host material oriented relative to the first host material such that a single laser beam can penetrate at least a portion of the first layer and at least a portion of the second layer, the second host material comprising an effective amount of a second laser-enhancing additive selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), and an alkyl sulfonate (e.g., RSO)₂Na or R-OSO₂Na) and thioesters;

wherein the first and second layers are operatively connected to each other and at least one of the first and second layers is operatively connected to the first surface of the central layer.

The article of claim 14.13, further comprising a gray scale image that can be laser imprinted into at least one of the first and second layers.

15.13, wherein the article is an identification document.

The article of claim 13, wherein the first layer is substantially transparent and the first laser-enhancing additive comprises from about 0.001 wt% to about 0.100 wt% of the entire weight of the first host material.

The article of claim 13, wherein the second layer is substantially transparent and the second laser-enhancing additive comprises from about 0.001 wt% to about 0.100 wt% of the entire weight of the second host material.

18.13, wherein at least one of the first and second host materials comprises a material that is less sensitive to laser radiation than the other of the first and second host materials.

The article of claim 13, wherein at least one of the first and second host materials comprises at least one material selected from the group consisting of: thermoset materials, thermoplastic materials, polymers, copolymers, polycarbonates, melt polycarbonates, polyesters, amorphous polyesters, polyolefins, silicon filled polyolefins, TESLIN, foamed polypropylene films, polyvinyl chloride, polyethylene, thermoplastic resins, engineering thermoplastics, polyethylene, polyamides, polystyrene, expanded polypropylene, Acrylonitrile Butadiene Styrene (ABS), ABS/PC, high impact polystyrene, polyethylene terephthalate (PET), PET-G, PET-F, polybutylene terephthalate (PBT), acetal copolymers (POM), Polyetherimides (PEI), polyacrylates, poly (4-vinylpyridine), poly (vinyl acetate), polyacrylonitrile, polymeric liquid crystal resins, polysulfones, polyether nitrides, and polycaprolactone.

The article of claim 13, further comprising a treated third layer disposed between the first and second layers, the third layer comprising a material through which the laser beam is transmitted.

21.13, wherein both the first and second layers are substantially transparent.

The article of claim 13, wherein the central layer is substantially opaque.

23. A method of imprinting by exposing a material to laser radiation, comprising:

adding to the material an effective amount of a laser-enhancing additive comprising:

copper potassium iodide (CuKI)₃) Or copper iodide (CuI); and at least one selected from zinc sulfide (ZnS), barium sulfide (BaS), and alkylsulfonic acid salt (e.g., RSO)₂Na or R-OSO₂Na) and thioesters; and

exposing the material to laser radiation in such a way that the material can be imprinted by the laser radiation.

24.23, wherein the effective amount of the laser-enhancing additive varies from 0.001 wt% to 100 wt% by weight of the material.

25.23, wherein the material is substantially transparent and the effective amount of the laser-enhancing additive varies from 0.001 wt% to 0.1 wt% of the material.

26.23, further comprising laser scribing a mark in gray scale on at least a portion of the material.

The method of 27.23, further comprising using the laser imprinted material in the production of the identification document.

28. A method of laser imprinting a gray scale image on an article having first and second layers, comprising:

adding a first effective amount of copper potassium iodide (CuKI) to the first layer₃) Or copper iodide (CuI);

adding a second effective amount of at least one selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates (e.g., RSO) to the second layer₂Na or R-OSO₂Na) and thioesters; and

a laser is directed so that it passes through at least a portion of the first layer and at least a portion of the second layer to form a gray scale image in at least one of the first and second layers.

29.23, further comprising:

a laser is directed so that it can pass through at least a portion of the first layer and at least a portion of the second layer so that the first and second layers can be bonded to each other.

30.28, wherein the first effective amount and the second effective amount together comprise about 0.001 wt% to about 0.1 wt% of the total weight of the first and second layers.

31.28, further comprising using the laser imprinted material in the production of the identification document.

32. A multi-layered identification document comprising:

a core layer;

a film layer overlying at least a portion of the core layer and bonded to a portion of the core layer, the film layer comprising an additive comprising:

an effective amount of copper potassium iodide (CuKI)₃) Or copper iodide (CuI); and

at least one selected from zinc sulfide (ZnS), barium sulfide (BaS), and alkylsulfonate (e.g., RSO)₂Na or R-OSO₂Na) and thioesters.

33.32, wherein the identification document carries a first mark thereon, the mark being obtainable by exposing the film layer to a laser.

34.33, wherein the mark comprises at least one of a gray scale image, a photograph, text, tactile text, graphics, information, a security pattern, a security mark, and a digital watermark.

35.33, wherein the first indicia contains variable information.

36.32, the identification document wherein the film layer is substantially transparent and wherein the additive comprises from 0.001 wt% to 0.1 wt% of the weight of the film layer.

37.36, the identification document of wherein the film layer further comprises:

a first sublayer comprising an effective amount of potassium copper iodide (CuKI)₃) Or copper iodide (CuI); and

a second sublayer comprising at least one member selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates (e.g., RSO)₂Na or R-OSO₂Na) and thioesters.

38. A method of making an identification document, comprising:

covering at least a portion of the central layer with a film layer comprising: copper potassium iodide (CuKI)₃) Or copper iodide (CuI); and

at least one selected from zinc sulfide (ZnS), barium sulfide (BaS), and alkylsulfonate (e.g., RSO)₂Na or R-OSO₂Na) and thioesters; and

the film layer is joined to a portion of the core layer.

39.38, further comprising directing a laser beam at least a portion of the thin film layer to create a first gray scale mark in the portion of the thin film layer.

D. Second aspect of the invention

D.1 characteristics

In a second aspect of the invention, the laser-enhancing additive of the invention described above may be added to at least part of the surface of the coating so that it can be laser-inscribed or marked, thereby helping to overcome the following problems: the materials used for laser marking or marking are responsive to laser marking and/or are not sufficiently responsive to laser marking of the gray scale image performed thereon. We have found that the ability to laser scribe at least some materials can be increased and/or the time to laser scribe at least some materials can be reduced by: a coating containing a laser enhancing additive of the present invention is applied to a given area of material to be laser engraved. It is also noted that the laser-enhancing additive containing the present invention may be applied to a sheet or another coating. We have also found that the compounds comprising the laser enhancing additives of the present invention described herein can be separated into two or more coatings, or into one coating and one flake, to improve laser inscription performance.

At least one embodiment of the second aspect of the invention is based on the surprising discovery that: the process of laser marking materials, particularly materials used in the manufacture of identification documents, can be improved and enhanced by applying a coating to the area of the material to be laser marked, the coating comprising a first effective amount of a first composition which is potassium copper iodide (CuKI)₃) Or copper iodide (CuI) in admixture with a second effective amount of a second composition, the second composition being at least one of: zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates (e.g., RSO)₂Na or R-OSO₂Na) and thioesters (e.g., substances containing-SH groups). Like the first aspect of the invention, CuI or CuKI₃And at least one of ZnS, BaS, alkylsulfonate, and thioester is referred to as "the laser-enhancing additive of the present invention".

In at least some embodiments, the total concentration of the laser-enhancing additive of the present invention in the coating varies from 0.001 wt% to 0.1 wt% by weight. In at least some embodiments, the laser-enhancing additive of the present invention is added at a greater concentration (e.g., from 0.1 wt% to 100 wt%). At concentrations greater than 0.1 wt.%, the laser-enhancing additives of the present invention may still be used to enhance laser marking or imprinting of the article or coated surface, but may compromise the transparency of the coating (if, in fact, the coating is initially sufficiently transparent or translucent). Advantageously, in at least one embodiment, the laser-enhancing additive of the present invention is present in the coating in an amount of about 0.06 wt%. In another advantageous embodiment, the 0.06 wt% comprises 0.03 wt% of CuI or CuKI₃And 0.03 wt% of at least one of ZnS, BaS, alkyl sulfonate, and thioester.

Of course, other ranges of concentration variations may be suitable for the laser-enhancing formulations of the present invention, particularly when the coating is used in opaque and colored materials, as will be appreciated by those of ordinary skill in the art. Furthermore, it will be recognized that the ratio of at least one of ZnS, BaS, alkyl sulfonate and thioester will follow CuI or CuKI₃Change in the proportion of at least one of them. That is, a given composition may contain, for example (purely for ease of illustration, using the example of a composition containing CuI and BaS), equal amounts of CuI and BaS, or 3 parts CuI to 5 parts BaS, 2 parts CuI to 1 part BaS, and so on. It is expected that those of ordinary skill in the art will be able to determine the optimum ratio in the correct experiment. Furthermore, we note that at least one of the beneficial compounds we have tested uses two sub-compositions (e.g., CuI and BaS in this example) in equal proportions.

The concentration of the laser-enhancing additive of the present invention suitable for a given coating depends, at least in part, on the properties of the coating (and in particular the binder material in the coating) sheet and the ultimate use, durability, and environmental conditions to which the coating is subjected. Higher concentrations of the laser-enhancing formulations of the present invention in the coating may affect one or more properties of the coating, such as transparency, durability, flexibility, opacity, and hardness, among others. Of course, under the right experimentation, the appropriate amount of the present additives for a particular coating can be determined. Additional factors may include the imprinting time, the imprinting process, and the desired quality of the imprinting.

It is contemplated that the laser-enhancing additive of the present invention may be added to coatings for any surface, article or product (using virtually any known method) so that such surface, article or product may be laser engraved, particularly to emboss a high quality gray scale image. Thus, it is believed that the laser-enhancing additives of the present invention may be applied to many different coated articles, including but not limited to identification documents, identification cards, credit cards, prepaid cards, telephone cards, smart cards, contact cards, contactless cards, compound contact-contactless cards, proximity cards (e.g., Radio Frequency (RFID) cards), electronic components, labels, packaging, containers, construction materials, piping materials, (automotive) transmission systems, aerospace and military products, computers, recording media, labels, tools and process devices, medical instruments, consumer goods and toys. Also, it is contemplated that the entire article may be made entirely or partially from a composition containing a laser-enhancing additive of the present invention and then laser engraved or marked.

As will be appreciated by those of ordinary skill in the art, the effective amount of the first and second compositions added to the coating will depend on the type of coating (e.g., binder material and/or other additives in the coating), the material being coated, and the laser engraving technique employed. In at least one embodiment, the laser-enhancing additive of the present invention in the coating comprises equal amounts of the first and second compositions described above. In at least one embodiment, the coating includes a second composition and a lesser amount of the first composition than the second composition. In at least one embodiment, the coating includes a first composition and a lesser amount of a second composition than the first composition.

As will also be appreciated by those of ordinary skill in the art, the laser enhancing additives of the present invention can be added to many different types of coatings, including organic coatings and opaque coatings, substantially transparent coatings and non-transparent coatings. In addition, in at least some embodiments, the coating containing the laser enhancing additive of the present invention further comprises a binder, which may be, for example, a latex, an emulsion, a thermosetting binder, or a thermoplastic binder. Examples of binder materials that we find suitable include resins, polyesters, polycarbonates, vinyls, acrylates, urethanes and cellulosic materials. It is expected that those of ordinary skill in the art will be readily able to determine coating formulations containing the laser-enhancing additives of the present invention using a wide variety of other binder materials such as paints, varnishes, latexes, acrylic fibers, epoxy resins, nitrocellulose, alkyd resins, melamine formaldehyde, polyamides, silicone resins, and polyvinyl butyral. Those of ordinary skill in the art will also recognize that any resin capable of forming a coating may be suitable for use in the present invention. Of course, coatings containing the laser-enhancing additives of the present invention may also include other additives known in the art, such as colorants (e.g., pigments or dyes), stabilizers, lubricants, adhesion promoters, surfactants, antistatic agents, thickeners, thixotropic agents, and the like.

By applying a coating containing the laser enhancing additive of the present invention to the surface of the material to be laser engraved, we have found that we can obtain high quality images and other engravings on articles such as multi-layer ID documents at desirable throughput output rates. High quality images include gray scale imprinted images (as described herein) and full color laser imprinted images (a particular description of such images is found in applicant's commonly assigned U.S. provisional patent application 60/344,674 filed 24/2/2001 entitled "full color laser imprinting system for identifying card images," attorney docket number P0504). Also, it is contemplated that the coatings of the present invention may be applied to portions of the surface of any article intended for laser marking, particularly gray scale image laser marking. The entire article or surface need not be coated.

It is believed that laser imprinting or marking of various articles including, but not limited to, identification documents, identification cards, credit cards, prepaid cards, telephone cards, smart cards, contact cards, contactless cards, compound contact-contactless cards, proximity cards (e.g., Radio Frequency (RFID) cards), electronic components, labels, packaging, containers, construction materials, piping materials, (automotive) transmission systems, aerospace and military products, computers, recording media, labels, tools and process equipment, medical devices, consumer goods and toys, and the like, can be improved by applying the coatings of the present invention to the surface of the article to be imprinted. Such improvements can be achieved on articles whose surface is the lamina to be laser engraved. Furthermore, as contemplated herein, the coatings of the present invention may be applied to other coatings (or materials) that cover the surface of an article to be laser imprinted or marked, as long as the "intervening" material between the surface to be laser imprinted or marked and the coating of the present invention is transparent to laser radiation.

In at least one embodiment, the coating of the present invention is used to improve the manufacture of identification documents, such as the identification document 10 of FIGS. 1 and 2. By selectively applying the coating of the present invention to the central layer of the identification document 10, the security of the document can be enhanced. Because the coating material can be applied by a controlled process (e.g., lithography, flexography, or screen printing), the orientation of the coating of the present invention (and the laser enhancing additive of the present invention) can be precisely controlled. The coating material is sensitive (or responsive) to the laser light, and thus the orientation of the coating of the present invention shows the location of imprint confidence. The selectable orientation of the laser sensitive material also helps to prevent counterfeiting since the laser-inscribed area is limited.

In one embodiment, the coating of the present invention is applied to an identification document, and the issuer of the identification document (e.g., a national DMV, passport voucher) is also involved in the design, which creates a unique coating pattern for the center of the document. To enhance the security of the document, the coating design can also be performed secretly, which prevents counterfeiting. Changing the coating material (e.g., adhesive) or concentration of additives or adhesives will change the orientation and reactivity of the coating, which better prevents counterfeiting, also makes it impossible to imprint a suitable mark on a local or more part of the identification document, and makes it difficult to reproduce the document.

It is also to be noted that the use of the inventive coating described herein may have at least some of the same advantages as the previously described use of the inventive laser-enhanced sheet (especially in the production of gray scale images) and will not be repeated here. Also, the laser used in the first aspect of the present invention described above is similar to that used in the second aspect of the present invention, and will not be repeated here.

In another embodiment of the present invention (described herein in relation to FIG. 8), the laser-enhancing additive of the present invention can be separated into two optically adjacent layers (e.g., a first layer comprising a coating and a flake, or two adjacent flakes (as described above), or a first layer comprising a coating and a second layer comprising a coating). This embodiment is beneficial for safety. For example, in laser engraving, the same visible image may be engraved in both layers, but depending on the proportion of the treated laser additive of the invention (and/or its layer component parts) in each layer, it is not necessary that the visible image look exactly similar in each layer. This may provide a visual effect that is difficult to reproduce.

For example, assume that a layer "close" to the laser beam (e.g., a top layer) has a first concentration of the laser-enhancing additive of the present invention, and a second layer further away from the laser beam (e.g., a layer below the top layer) has a second, higher concentration of the laser-enhancing additive of the present invention. When both layers are laser engraved, the bottom layer will have a visible laser engraved image and the top layer will have a so-called "latent" laser engraved image, which may be more blurred but still visible to the naked human eye. It is also contemplated that either of the two layers may contain a colorant (e.g., visible and invisible (e.g., IR, UV) colorant) that distinguishes between visible laser-engraved images and latent laser-engraved images.

By "optically adjacent" is meant that a laser can pass from one layer (e.g., one lamina) to the other (e.g., the second lamina or the central layer or the layer with the coating thereon) such that the same laser can laser scribe both layers simultaneously. Although it is possible that two optically adjacent layers are immediately adjacent, they need not be. The two layers may be directly adjacent (e.g. they are fused together) or may be separated by a material through which the laser beam can pass but which itself reacts to the laser beam. For example, the two layers may be separated by an adhesive through which the laser beam can pass, or may be separated by another type of material through which the laser beam can pass (e.g., a film layer).

"compartmentalized laser enhancing additive" includes any of the following embodiments:

(a) the desired concentration of the additives, for example, in a proportion by weight of 0.06%,

the division can be made in two light-adjacent layers, for example 0.03 wt% in the first layer of the sheet, 0.03 wt% in the second layer applied to the second sheet, the first and second sheets being light-adjacent, or 0.06 wt% in the one layer comprising the coating and 0.03 wt% in the other layer comprising the coating; or

(b) The first portion of the laser enhancing additive of the invention is in a first layer (the "first portion" being one of two portions of the laser enhancing additive of the invention, the portion containing either at least one of copper potassium iodide or copper iodide, or at least one of zinc sulfide, barium sulfide, alkyl sulfonates, and thioesters), and the second portion of the laser enhancing additive of the invention (e.g., the other of the two portions of the laser enhancing additive of the invention) is in a further layer, the two layers being optically adjacent.

For (a) and (b) above, the two layers may be, for example:

(i) two sheets

(ii) Two coatings applied to a given sheet

(iii) A core layer with a coating and a foil connected to the core layer

(iv) Sheet and coating applied to the sheet

(v) A first sheet having a coating layer attached to a second sheet and the second sheet having the coating layer.

Finally, in another aspect of the invention, we have surprisingly found that LAZERFLAIR pigments can be added to a coating (as in the manner described above for the addition of the laser-enhancing additive of the invention to the coating) to allow for laser marking or marking of gray scale markings on an article. It is known that when LAZERFLASR pigment is added to the actual material to be imprinted, it is a laser enhancing additive (see http:// www.empigments.com/LazerFlair. cfm), thereby improving contrast. Our experiments have found that laser inscription of an article (e.g., a center layer in an identification document) can also be improved by adding LAZERFLAIR pigment to the coating applied to the article. The LAZERFLAIR additive is available from EM Pigments (available from 7 Skyline Drive, Hawthorne, NY 10532 USA and EM Pigments).

D.2 preparation/manufacture

Embodiments of the coating of the present invention may be performed in any known manner to those of ordinary skill in the art. For example, in one embodiment, the coating of the present invention comprises an organic polymer binder, potassium copper iodide, zinc sulfide, and the potassium copper iodide and zinc sulfide can be mixed together with the organic polymer binder using a mixer; for example, the additives may be ground using a ball mill to reduce particle size or extrusion of the organic polymer binder.

In another embodiment, the laser-enhancing additive of the present invention may be added to the coating as part of a masterbatch, as previously described for the laser-enhancing additive of the present invention added to the flake. For example, a master batch containing 0.03 wt% copper potassium iodide and 0.03 wt% zinc sulfide can be made and mixed with each of the two compounds.

Although at least one advantageous embodiment of the invention uses a coating which is in liquid form when applied in an ID document, the use of a liquid coating is not essential. For example, those of ordinary skill in the art will be able to use the laser-enhancing additive of the present invention in a coating that is not in liquid form (e.g., a heat-liquefiable solid or powder) under the proper experimentation.

D.3 exemplary embodiments

FIG. 7 is a schematic cross-sectional view of an identification document according to an embodiment of the second aspect of the invention. In the embodiment of FIG. 7, the ID document 10 preferably includes a multi-layer structure. Although the cross-sectional configuration and elements shown in FIG. 7 differ from those of the prior art, for ease of illustration, the ID document 10 has a front-out appearance that is very similar to the ID document 10 of FIG. 1. In fig. 7, the center material 50 (for ease of illustration only, TELSIN in this example) has a top surface 67 and a bottom surface 69. Although not illustrated in FIG. 7, the central material 50 may also be pre-printed with one or more indicia, such as variable information about the identity of the bearer of the document 10, using a method such as color laser xerography (illustrated in FIG. 5 as being printed on the central layer 50). A portion of the top surface 67 of the core material 50 is coated with a coating 70 of the present invention containing a laser-enhancing additive of the present invention. Of course, the inventive coating 70 may also be applied to the bottom surface 69, if desired.

In fig. 7, the coating 70 of the present invention is selectively applied so that only specific areas of the core material 50 are sensitive to laser scribing. Thus, energy 72 from a laser (not shown) can be specifically directed to the area of the ID document 10 containing the coating 70 of the invention, thereby creating indicia 541, 54m on the coated material (in this case, the central layer 50). For example, in the production of identification documents, the selective application of the coating 70 of the present invention is beneficial because the orientation and position of the coating is secret, thereby helping to prevent counterfeiting. For example, a counterfeit may not be able to show what information was laser engraved on the card and what information was not. Even those counterfeits that can be lasered may not know which areas of the identification document are imprintable. Changing any component in the identification document, such as the adhesive, the laser enhancing additive of the invention, or the concentration of the laser enhancing additive of the invention, will change the orientation and reactivity of the coating, which better prevents counterfeiting.

Another security advantage is shown in the embodiment of fig. 7. If non-variable or non-personal information (e.g., the name of the issuer) is pre-printed on the central layer 50 and then the coating 70 of the present invention is applied, the identification document 10 can be personalized (e.g., with variable information such as images, signatures, birth dates, or biometric data) by laser engraving the variable information into the coated portion of the central layer 50. Such laser imprinting may even occur if a thin sheet is applied to the inventive coating 70, if laser energy is able to pass through the thin sheet to the inventive coating 70 and the central layer 50.

In fig. 7, a sheet 74 is shown on top of the inventive coating 70. The foil 74 may be applied before or after laser imprinting of the coated areas of the center layer 50. For example, if the sheet 74 is transparent to laser radiation, its application to the inventive coating 70 will not interfere with the ability of the laser radiation 72 to penetrate to reach the inventive coating 70 and the core layer. However, if the sheet 74 is opaque to the laser radiation 72, it may be used after laser inscription of the center material 50 has occurred.

The coating 70 of the present invention can be applied to the surface 67 using any known method (e.g., lithography, flexography, screen printing, spraying, dipping, immersion, brushing, spinning, masking the desired area of application, etc.). The thickness of the coating 70 depends on the article being coated and for ID documents such as ID cards, the thickness varies from about 0.01 microns to 50 microns. It will be appreciated that other articles laser engraved may require or use coatings of different thicknesses.

Although fig. 7 illustrates that coating 70 only covers a portion of top surface 67, this is not limiting. The coating 70 may be applied to any surface and may cover the entire surface if desired.

We have found that the inventive coatings described herein have one or more advantages. For example, suitable gray scale image lasers can be marked or imprinted onto the coated material using the coatings of the present invention. Furthermore, laser inscription or marking can be carried out more quickly using the coatings of the invention at lower laser energies. Also, the coatings of the present invention can be selectively applied to articles such as identification documents to increase security and prevent counterfeiting. Also, laser engraving using the coatings of the present invention is durable, wear resistant and environmentally friendly.

D.4 further embodiments of the second aspect of the invention

It is expected that at least the following and other similar compositions are useful examples of the second aspect of the invention:

1. a coating having laser-inscribing properties, comprising:

a carrier material for the liquid; and

an effective amount of a laser-enhancing additive, the laser-enhancing additive comprising:

a first amount of copper potassium iodide (CuKI)₃) Or copper iodide (CuI); and

a second amount of zinc sulfide (ZnS), barium sulfide (BaS), an alkyl sulfonate (e.g., RSO)₂Na or R-OSO₂Na) and thioesters.

2.1, wherein the laser-enhancing additive is present in an amount of about 0.001 wt% to 100 wt% based on the weight of the total composition.

3.1, wherein the liquid carrier is substantially transparent and the laser-enhancing additive comprises about 0.001 wt% to about 0.1 wt% of the total composition.

4.1, wherein the laser-enhancing additive comprises about 0.06 wt% of the total composition.

5.4, wherein each of the first and second amounts comprises about 0.03 wt% of the total composition.

6.1, wherein the first amount and the second amount are the same.

7.1, wherein the first amount is greater than the second amount.

8.1, wherein the first number is less than the second number.

9.1 coating of the type described in diode-pumped Nd: Yag laser, optically pumped Nd: YAG laser, CO₂The substrate coated with the present coating is laser-inscribable by at least one of laser and excimer laser radiation.

The coating of claim 1, wherein the liquid carrier material comprises at least one of: resins, polyesters, polycarbonates, vinyls, acrylates, urethanes, cellulosics, thermosets, thermoplastics, polymers, copolymers, polycarbonates, molten polycarbonates, polyesters, amorphous polyesters, polyolefins, silicon-filled polyolefins, TESLIN, foamed polypropylene films, polyvinyl chloride, polyethylene, thermoplastic resins, engineering thermoplastics, polyethylene, polyamides, polystyrene, expanded polypropylene, acrylonitrile-butadiene-styrene (ABS), ABS/PC, high impact polystyrene, polyethylene terephthalate (PET), PET-G, PET-F, polybutylene terephthalate (PBT), acetal copolymers (POM), Polyetherimides (PEI), polyacrylates, poly (4-vinylpyridine), poly (vinyl acetate), poly (ethylene glycol terephthalate), poly (butylene glycol terephthalate) (POM), poly (ethylene glycol terephthalate) (co-styrene), poly (ethylene glycol terephthalate), poly (ethylene glycol, Polyacrylonitrile, polymeric liquid crystal resins, polysulfones, polyether nitrides and polycaprolactones.

11. A substrate capable of laser-engraving a gray-scale image, comprising:

a central layer having a first surface; and

a coating applied to at least a first region of the first surface, the coating comprising:

a first effective amount of a composition comprising copper potassium iodide (CuKI)₃) Or copper iodide (CuI); and

a second effective amount of a compound selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates (e.g., RSO)₂Na or R-OSO₂Na) and thioesters;

wherein laser energy directed at the first region of the central layer is capable of forming a gray scale mark therein.

12. A substrate capable of laser imprinting gray scale markings thereon, comprising:

a central layer having a first surface;

a first coating applied to at least a first region of the first surface, the coating comprising an effective amount of a first laser-enhancing additive comprising copper potassium iodide (CuKI)₃) Or copper iodide (CuI); and

a second coating applied to at least a second region of the core layer, the coating comprising an effective amount of a second laser-enhancing additive selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates (e.g., RSO)₂Na or R-OSO₂Na) and thioesters;

the first and second zones at least partially overlie the central layer to define a third zone on the central layer;

wherein laser energy directed at the third region of the central layer is capable of forming a gray scale mark therein.

13. A method of manufacturing an identification document, comprising:

providing a center comprising a top plane and a bottom plane; and

applying a laser-enhancing additive to at least a portion of the top plane, the laser-enhancing additive comprising:

an effective amount of copper potassium iodide (CuKI)₃) Or copper iodide (CuI); and

an effective amount of at least one of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonate and thioester.

14.13, further comprising laminating at least the top planar surface of the center and a foil together.

15.13, further comprising directing a laser beam so that it passes through at least a portion of the coating layer and to the center layer to form a gray scale mark on the center layer.

The method of 16.13, wherein the core comprises at least one of TESLIN, polycarbonate, polyester, and polyvinyl chloride.

E. Third aspect of the invention

In a third aspect of the invention, the invention employs the laser-enhanced sheet of the invention (or components thereon) in more than one layer on an identification document. Several embodiments of this aspect have been described above in relation to the first and second aspects of the invention. Another embodiment of this aspect is described below.

FIG. 8 is a schematic cross-sectional view of an identification document according to a second embodiment of the second aspect of the invention. In the embodiment of FIG. 8, the ID document 10 preferably includes a multi-layer structure, and as previously described, the laser enhancing additive of the present invention is divided between two optically adjacent layers. Although the cross-sectional configuration and elements shown in FIG. 8 differ from those of the prior art, for ease of illustration, the ID document 10 has a front-out appearance that is very similar to the ID document 10 of FIG. 1. In the embodiment of FIG. 8, a first portion of the laser enhancing additive of the present invention is disposed in a first coating 76 and a second portion of the laser enhancing additive of the present invention is disposed in a sheet 78 applied in the middle of the first coating 76. The ultra-flakes 74 are applied to the intermediate flakes 78. The first coating 76 is applied to the center layer 50, which in fig. 8 is made of an opaque white material such as TESLIN or polycarbonate.

In the embodiment of fig. 8, first coating 76 comprises a first effective amount of potassium copper iodide (CuKI)₃) Or copper iodide (CuI), and the intermediate sheet 78 contains a second effective amount of at least one of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters. In this embodiment, the first effective amount is greater than the second effective amount. The first coating 76 and intermediate sheet 78 are configured and arranged to allow laser radiation 72 to pass through the first coating 76 and intermediate sheet 78 to form indicia 54n, 54o and potentially indicia 82 and 84 on the ID document 10. Although not shown in the cross-sectional view of fig. 8, our experiments show that the markings 541 and 54m formed on the central layer 50 may be suitable gray scale images (by use, this at least means that the image is for security purposes, such as identification or authentication). As previously described, the underlying indicia 82 and 84 are lighter and less visible (and still visible) relative to the indicia 54n and 54 o.

The latent indicia 82 and 84 are beneficial as a security feature since in one attempt a counterfeiter may remove the intermediate sheet 78 to alter the information in the sheet 78, but this information is still present on the central layer 50 with the first coating 76. Similarly, to change the information on the center layer 78, a counterfeiter may attempt to remove the intermediate sheet 78 and then replace it, but the underlying indicia 82 and 84 are still present and visible on the intermediate sheet 78. As will be appreciated by those of ordinary skill in the art, the type and orientation of the marks formed on the central layer 50 will depend on the particular type of laser used, the manner in which the laser is used (e.g., pumped), and the durability of the application of the laser energy.

It should be understood that although the example of fig. 8 shows first coating 76 containing an effective amount of potassium copper iodide (CuKI)₃) Or cuprous iodide(CuI) and the intermediate foil 78 contains an effective amount of at least one of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters, but the positions of the two compounds in the first and second layers, respectively, may be reversed. That is, the first coating 76 may include an effective amount of at least one of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonate, and thioester, and the intermediate sheet 78 may include an effective amount of copper potassium iodide (CuKI)₃) Or cuprous iodide (CuI).

And (4) conclusion:

depending on the effectiveness of the laser, the identification document of the invention can be produced both in a public environment and in a centrally issued environment. An example of a printing device suitable for use in at least some of the disclosed embodiments of the present invention is the DATACARD DCL30 desktop Laser Personalization System, available from Datacard group Minnetonka, Minnesota.

In one embodiment, after lamination and laser engraving, the identification document 10 is cooled and cut (e.g., by die cutting) to produce a product of predetermined dimensions. However, in at least one embodiment, the substrate and the sheet can be sized such that cutting the substrate to be laminated printed is not required.

The identification document 10 of the present invention can be made in any desired size. For example, the size of the identification document may vary from the size of a standard business card (47.6 × 85.7mm) to the size of the identification booklet document (127 × 177.8mm), and the thickness may vary from 0.3mm to 1.3 mm. At least some of the identification documents of the embodiments of the invention meet all of the requirements of ISO 7810, 1985, namely a size CR-80, 85.47-85.73mm wide, 53.92-54.03mm high, 0.69-0.84mm thick. The new CR-80 model certificate is circular and has a radius of 2.88-3.48 mm.

Furthermore, while the description has been made with respect to more desirable embodiments of cyan, magenta, and yellow dyes, the invention is not so limited. The invention may include additional colors, alternative color schemes, and even mottled colors. Also, while the present invention has been described with respect to NIR, the techniques of the present invention may be extended to dyes that are responsive in the ultraviolet spectrum and other IR ranges.

Also, while some examples have been disclosed above with particular center portions (e.g., TESLIN), it is to be understood that the compositions, methods, articles, features and processes of the present invention can also be applied to other center-based identification documents, such as those made from other materials. For example, in an embodiment describing a polycarbonate or polyester as exemplary superflakes, many other superflake materials may be used, as will be appreciated by those of ordinary skill in the art.

Likewise, the inventive coatings described herein may also impart photosensitivity to other core portions. Furthermore, we shall note that the coating of the invention can be applied both in the center of the document and in the ultra-thin sheet; laser engraving can be performed either in the center (or one of them) or in the ultra-thin sheet.

Although the principles of the technology have been described and illustrated with respect to particular applications, the technology can be applied in many different ways.

Although certain words, languages, phrases, terms and product labels may be used herein to describe various features of embodiments of the invention, their use is not limited. The use of a given word, phrase, language, term or product label can include all grammatical, textual, scientific, technical and functional equivalents. The terminology used herein is for convenience of description and is not limiting.

The techniques disclosed herein may be used in combination with other techniques. Examples include the techniques described in detail in the following U.S. patents and applications: 6,022,905, 5,298,922, 5,294,774, 4,652,722, 5,824,715, 5,633,119, and applications 09/747,735 (filed 12/22/2000) and 09/969,200 (filed 10/2/2001). Also, in addition to ID documents, the techniques of the present invention may also be applied to product labels, product packaging, business cards, packages, charts, maps, labels, and the like, particularly those articles that include laser engraving of ultrathin sheet structures. The ID documents described herein broadly include such labels, packaging, cards, and the like. Furthermore, although some examples have been disclosed above with specific central portions, it should be noted that the lamellae may also be light-sensitised with other central portions.

In the embodiments detailed above, the particular combination of elements and features is exemplary only; the interconversion and substitution between these compositions and those mentioned in this and the above patents/applications are also specifically contemplated. As those skilled in the art will recognize, those variations, modifications, and other applications of the invention described herein can occur to those skilled in the art without departing from the spirit and the scope of the invention as defined by the appended claims. Accordingly, the foregoing description is by way of example only, and not limiting. The scope of the invention is set forth in the appended claims.

Claims (59)

1. A composition having laser-inscribing properties, said composition comprising:

a polymeric host material; and

an effective amount of a laser-enhancing additive incorporated into a polymeric host material, said laser-enhancing additive comprising:

a first amount of copper potassium iodide (CuKI)₃) Or copper iodide (CuI); and

a second amount of at least one of zinc sulfide (ZnS), barium sulfide (BaS), an alkyl sulfonate, and a thioester;

wherein the laser enhancing additive is present in an amount of from 0.001 to 0.2% by weight of the total composition.

2. The composition of claim 1, wherein the laser-enhancing additive comprises 0.06 to 0.12% by weight of the total composition.

3. The composition of claim 1, wherein the composition comprises a coating.

4. The composition of claim 1, wherein the composition comprises flakes.

5. The composition of claim 1, wherein the composition is laser engravable to form a gray scale image.

6. A composition capable of being incorporated into a predetermined polymeric material to improve the laser inscription properties of said predetermined polymeric material, said composition comprising:

a first laser-enhancing additive present in the composition at a level of from 0.001% to 99% by weight of the total composition, said first laser-enhancing additive comprising:

a first amount of copper potassium iodide (CuKI)₃) And cuprous iodide (Cul); and

a second amount of at least one substance selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters; and

a polymeric host material mixed with said first laser-enhancing additive, the polymeric host material comprising a material of the same type of material as said predetermined polymeric material.

7. The composition of claim 6, wherein the polymeric host material and first laser-enhancing additive are formed together into a masterbatch.

8. The composition of claim 6, wherein the composition is prepared such that it can be mixed into the polymeric material and extruded into at least one of a film and a sheet product.

9. The composition of claim 6, wherein the first laser enhancing additive is present in the composition in an amount of 0.01 to 0.20% by weight of the total composition.

10. The composition of claim 8, wherein the first laser enhancing additive is present in the composition in an amount of from 0.05 to 0.13% by weight of the total composition.

11. The composition of claim 6, wherein the composition further comprises a second laser-enhancing additive, the second laser-enhancing additive being different from the first laser-enhancing additive.

12. The composition of claim 6, wherein the polymeric material comprises polycarbonate, fused polycarbonate, whitish polycarbonate, near-white polycarbonate, titanium dioxide filled polycarbonate, polyester, amorphous polyester, polyolefin, silicon filled polyolefin, foamed polypropylene film, polyvinyl chloride, polyethylene, polyurethane, polyamide, expanded polypropylene, at least one of acrylonitrile-butadiene-styrene (ABS), ABS/PC, polyethylene terephthalate (PET), PET-G, PET-F, polybutylene terephthalate (PBT), acetal copolymer (POM), polyetherimide, polyacrylate, poly-4-vinylpyridine, polyvinyl acetate, polyacrylonitrile, polymeric liquid crystal resins, polysulfone, polyether nitride, and polycaprolactone.

13. The composition of claim 6, wherein the first laser-enhancing additive is present in the composition in an amount sufficient to laser-imprint a gray scale image on the polymeric material after the composition is mixed with the polymeric material.

14. The composition of claim 13, wherein the amount of said first laser-enhancing additive sufficient to laser-imprint a gray scale image on the polymeric material is 0.05-0.13 wt%.

15. The composition of claim 6, wherein the composition is capable of being incorporated into a polymeric coating when the composition is prepared.

16. The composition of claim 6, wherein the composition is capable of being incorporated into a polymer sheet at the time of its preparation.

17. The composition of claim 6, wherein the composition is extruded proximate to a polymer that does not contain the first laser-enhancing additive.

18. The composition of claim 6, wherein the polymeric host material comprises a material capable of being used as a coating.

19. The composition of claim 18, wherein the material capable of functioning as a coating comprises at least one of a resin, a polyester, a polycarbonate, a vinyl, an acrylate, a urethane, and a cellulose-based coating material.

20. An article prepared using a composition capable of being incorporated into a predetermined polymeric material to improve the laser inscription performance of the predetermined polymeric material, the composition comprising:

a first laser-enhancing additive present in the composition at a level of from 0.001% to 99% by weight of the total composition, said first laser-enhancing additive comprising:

a first amount of copper potassium iodide (CuKI)₃) And copper iodide (CuI); and

a second amount of at least one substance selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters; and

a polymeric host material mixed with said first laser-enhancing additive, the polymeric host material comprising a material of the same type of material as said predetermined polymeric material.

21. The article of claim 20, wherein the article comprises at least a portion of an identification document.

22. An article capable of laser-engraving a gray scale mark, the article comprising:

a first layer comprising a first polymeric host material comprising an effective amount of a first laser-enhancing additive comprising potassium copper iodide (CuKI)₃) Or copper iodide (CuI), the first laser enhancing additive being present in an amount of 0.001 to 99% by weight of the total weight of the first polymeric host material; and

a second layer attached to the first layer, the second layer comprising a second polymeric host material oriented with respect to the first polymeric host material such that a single laser can penetrate at least a portion of the first layer and at least a portion of the second layer, the second polymeric host material comprising an effective amount of a second laser-enhancing additive selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters, the second laser-enhancing additive being present in an amount of 0.001 to 99% by weight of the total weight of the second polymeric host material.

23. The article of claim 22, further comprising laser engraving a grayscale image into at least one of the first and second layers.

24. The article of claim 22, wherein the article comprises a sheet.

25. The article of claim 22, wherein the article comprises an identification document.

26. The article of claim 22, further comprising a substrate layer having a first surface, wherein at least one of the first and second layers is attached to the first surface of the substrate layer.

27. The article of claim 26, wherein the substrate layer comprises a material that is not laser-inscribable to form gray scale markings.

28. The article of claim 22, wherein at least one of the first and second layers comprises a sheet.

29. The article of claim 22, wherein at least one of the first and second layers comprises a coating.

30. The article of claim 29, wherein the layer comprising the coating is applied to at least one covert location.

31. An article capable of being used for laser engraving, the article comprising:

a base material having a first surface; and

a layer applied to the first surface of the base material, the layer comprising:

a first amount of copper potassium iodide (CuKI)₃) And copper iodide (CuI); and

a second amount of at least one substance selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters; and

a polymeric host material mixed with said first and second quantities of matter, said polymeric host material comprising a material of the same type of material as said base material, wherein the total amount of said first and second quantities of matter is from 0.001 to 99% of the total weight of said polymeric host material.

32. The article of claim 31, wherein the article comprises an identification document.

33. The article of claim 31, wherein the mixture of the first and second quantities of substance is present in the polymeric host material in an amount sufficient to allow the layer to be laser engraved with a gray scale image.

34. The article of claim 31, wherein the mixture of the first and second quantities of substance is present in the polymeric host material in an amount of 0.01 to 0.20 wt%.

35. The article of claim 31, wherein the polymeric host material comprises polycarbonate, fused polycarbonate, whitish polycarbonate, near-white polycarbonate, titanium dioxide filled polycarbonate, polyester, amorphous polyester, polyolefin, silicon filled polyolefin, foamed polypropylene film, polyvinyl chloride, polyethylene, polyurethane, polyamide, expanded polypropylene, acrylonitrile Butadiene Styrene (ABS), ABS/PC, polyethylene terephthalate (PET), PET-G, PET-F, polybutylene terephthalate (PBT), acetal copolymers (POM), polyetherimides, polyacrylates, poly (4-vinylpyridine), poly (vinyl acetate), polyacrylonitrile, polymeric liquid crystal resins, polysulfones, polyether nitrides and polycaprolactones.

36. The article of claim 31, wherein the layer comprises a foil layer applied to at least a portion of the base material.

37. The article of claim 31, wherein the layer comprises a coating applied to at least a portion of the substrate material.

38. The article of claim 37, wherein the coating is applied to at least one covert location.

39. The article of claim 31, wherein the layer further comprises:

a first layer comprising a first quantity of a substance mixed with the polymeric host material; and

a second layer comprising a second quantity of a substance mixed with the polymeric host material;

wherein the first and second layers are positioned such that a single laser beam can penetrate at least a portion of the first layer and at least a portion of the second layer.

40. An identification document, the document comprising:

a center layer;

a first layer covering at least a portion of said core layer and bonded to a portion of said core layer, said first layer comprising an additive comprising:

an effective amount of copper potassium iodide (CuKI)₃) Or copper iodide (CuI); and

an effective amount of at least one substance selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters,

wherein the total amount of said additives is from 0.001 to 99% by weight of the total weight of said first layer.

41. The identification document of claim 40, wherein the first layer is at least one of a coating and a sheet.

42. The identification document of claim 40, wherein the identification document bears a first mark thereon, the mark being obtained by irradiating at least a portion of the first layer with a laser beam.

43. The identification document of claim 40, wherein the indicia includes at least one of a grayscale image, a photograph, text, tactile indicia, vector information, pixel information, graphics, information, a security pattern, a security indicia, and a digitized watermark.

44. The identification document of claim 40, wherein the first indicia includes variable information.

45. The identification document of claim 40, wherein the first layer further comprises:

a first sublayer comprising an effective amount of at least one of copper potassium iodide (CuKI3) or copper iodide (CuI); and

a second sublayer comprising an effective amount of at least one material selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters.

46. A composition capable of being incorporated into a polymeric material to improve the laser inscription properties of the polymeric material, the composition comprising:

a first amount of a first additive comprising potassium copper iodide (CuKI)₃) And copper iodide (CuI); and

a first polymeric host material mixed with said first additive, said first polymeric host material comprising a material of the same type as said polymeric material, wherein said first additive is present in an amount of from 0.001 to 99% by weight of the total weight of said first polymeric host material;

a second amount of a second additive comprising at least one substance selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters; and

a second polymeric host material mixed with said second additive, said second polymeric host material comprising a material of the same type as said polymeric material, wherein said second additive is present in an amount of 0.001 to 99% by weight of the total weight of said second polymeric host material.

47. An article made using the composition of claim 46, wherein the first additive and the first polymeric host material are provided in a first layer applied to the article and the second additive and the second polymeric host material are provided in a second layer applied to the article, wherein the first and second layers are different layers from each other at least when applied to the article, the first and second layers being configured and arranged such that a single laser beam can penetrate at least a portion of the first layer and at least a portion of the second layer.

48. The article of claim 47, in which at least one of the first and second layers comprises a sheet.

49. The article of claim 47, in which at least one of the first and second layers comprises a coating.

50. The article of claim 49, wherein the coating is applied to at least one covert location.

51. An article prepared using a composition capable of being incorporated into a polymeric material to improve the laser inscription performance of the polymeric material, the composition comprising:

a first amount of a first additive comprising potassium copper iodide (CuKI)₃) And copper iodide (CuI); and

a first polymeric host material mixed with said first additive, said first polymeric host material comprising a material of the same type as said polymeric material, wherein said first additive is present in an amount of from 0.001 to 99% by weight of the total weight of said first polymeric host material;

a second amount of a second additive comprising at least one substance selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters; and

a second polymeric host material mixed with said second additive, said second polymeric host material comprising a material of the same type of material as said polymeric material, wherein said second additive is present in an amount of 0.001 to 99% by weight of the total weight of said second polymeric host material,

wherein the article comprises an identification document.

52. A method of improving laser inscription performance of a polymeric material, the method comprising:

providing a polymeric host material comprising the same material as the polymeric material;

preparing a mixture comprising a blend of the polymeric host material and a laser-enhancing additive comprising:

a first amount of copper potassium iodide (CuKI)₃) And copper iodide (CuI); and

a second amount of at least one substance selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters;

wherein the total amount of the first and second quantities is from 0.001 to 99% by weight of the total weight of the polymeric host material,

extruding the mixture into the polymeric material.

53. The method of claim 52, wherein the polymeric material comprises polycarbonate, fused polycarbonate, whitish polycarbonate, near-white polycarbonate, titanium dioxide filled polycarbonate, polyester, amorphous polyester, polyolefin, silicon filled polyolefin, foamed polypropylene film, polyvinyl chloride, polyethylene, polyurethane, polyamide, expanded polypropylene, acrylonitrile Butadiene Styrene (ABS), ABS/PC, polyethylene terephthalate (PET), PET-G, PET-F, polybutylene terephthalate (PBT), acetal copolymer (POM), Polyetherimide (PEI), polyacrylate, poly 4-vinylpyridine, polyvinyl acetate, polyacrylonitrile, polymeric liquid crystal resins, polysulfone, polyether nitride, and polycaprolactone.

54. A method of making an identification document, the method comprising:

providing a core layer having a first surface;

covering at least a portion of a first surface of said core layer with a first layer, said first layer comprising a laser-enhancing additive in an amount of 0.001 to 99% by weight of the total weight of said first layer, said laser-enhancing additive comprising:

copper potassium iodide (CuKI)₃) Or copper iodide (CuI); and

at least one substance selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonates, and thioesters.

55. The method of claim 54, wherein the laser-enhancing additive is present in the first layer in an amount of 0.001 to 0.25 wt% of the total weight of the first layer.

56. The method of claim 54, wherein the first layer comprises at least one of a coating or a flake.

57. A method according to claim 56, wherein the first layer overlays at least one secret location of the central layer.

58. The method of claim 54, further comprising imprinting a mark on at least a portion of the first layer.

59. The method of claim 58, wherein the indicia comprises at least one of grayscale images, photographs, text, tactile indicia, vector information, pixel information, graphics, information, security patterns, security indicia, and digital watermarks.