A Path to the Next Generation of U.S. Banknotes Keeping Them Real (2007) / Chapter Skim
Currently Skimming:
Appendix D Long-Term Feature and Feature Platform Descriptions
Appendix D Long-Term Feature and Feature Platform Descriptions
Pages 227-296
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 227... ...
• Key Development Risks and Issues: Phase I -- A discussion of the durability challenges, feature aesthetics, anticipated social acceptability, and descrip
|
From page 228... ...
The features described in this appendix are as follows: • Anomalous Currency Space • Chemical Sensors • Digitally Encrypted Substrate • Engineered Cotton Fibers • e-Substrate • NiTi Shape Memory and Superelastic Responsive Materials • Smart Nanomaterials • Tactilely Active Electronic Features
|
From page 229... ...
The ACS provides for the incorporation of heterogeneous materials into the FRN in a manner that would not allow the ACS region to be inconspicuously removed or tampered with; also, these materials would have durability for the lifetime of the banknote. Potential Implementations The clear plastic window or variations on this theme are already in use in some foreign currencies, so it appears that this feature platform concept has been successfully introduced.
|
From page 230... ...
This volume could be (fully or partially) filled with a novel material or composite, including current microscale and nanoscale materials and those in development as part of the National Nanotechnology Initiative (NNI)
|
From page 231... ...
There are many ways in which a banknote designer could apply the ACS feature platform concept. A few ideas include the following: • Strip along outer edge.
|
From page 232... ...
The requisite manufac turing technologies would depend entirely on the feature design and the materi als selected for the feature application. The ACS provides a flexible mechanism whereby these advanced materials can be incorporated into currency with mini mum disruption to the production process.
|
From page 233... ...
Key Development Risks and Issues: Phase I Since a wide range of highly durable materials will be available for the ACS, as well as rigorous testing methods by which this durability may be characterized, durability will need to be evaluated but probably will not be a major constraint. The ability to integrate a window or other ACS into the FRN is really a question of whether sufficiently strong bonding can be formed between the cotton-linen paper and the material(s)
|
From page 234... ...
There are many opportunities for features within this technology area, so Phase I activities can determine which potential features are of greatest interest for counterfeit deterrence. Feasibility experiments can be conducted, through a combination of laboratory-based work and modeling and simulation analysis, to select the most promising future directions for currency applications.
|
From page 235... ...
is a major goal of many of these advanced materials-based projects. Therefore, it is possible that at least some ACS-based features will have the same cost as that for the current security thread.
|
From page 236... ...
a P at h n e xt g e n e r at i o n U.s. Banknotes to the of CHEMICAL SENSORS Description Sensors embedded in banknotes could detect a human-produced or gadget produced chemical and generate a human-detectable signal.
|
From page 237... ...
Chemical sensors are difficult to reproduce by opportunist counterfeiters and petty criminals because neither the sensors nor the materials required to make them are readily available in the marketplace. Professional criminal counterfeiters would also be deterred by the difficulty of reproducing these sensors well.
|
From page 238... ...
Passive Sensors: Liquid Crystals Liquid crystals sandwiched between porous plastic films could be fabricated so that one end of each crystal was attracted to a specific chemical and the other end was repelled. The plastic films could be finely grooved to ensure that the liquid crystals were initially aligned with their long axes oriented parallel to the plane of the banknote.
|
From page 239... ...
Many organic compounds are highly fluorescent, and they can be designed so that their fluorescent spectra and/or brightness can change upon exposure to a specific chemical. These changes can be observed under UV illumination in the same way as that described above for oxygen quenching.
|
From page 240... ...
Key Development Risks and Issues: Phase I Significant development issues must be addressed for this feature to be viable as a counterfeit deterrent. The most critical issues are the following: • The selection of the human-produced chemical to detect that covers the range of human variability.
|
From page 241... ...
aPPendix d Development Plan: Phase I The committee determined that the development challenges for chemical sensors were sufficiently high, compared with those for the other feature concepts, that pursuing a development program at this stage would be premature. Estimate of Production Costs The production costs cannot reasonably be estimated at this point.
|
From page 242... ...
This method would be extremely difficult to copy, since each note is unique, and re-creating the exact fiber pattern in the substrate would be virtually impossible. The limitation of this approach is the need to scan, photograph, or otherwise cap ture a picture of the substrate and process the picture.
|
From page 243... ...
aPPendix d Feature Motivation This feature has a high rating from the committee owing to the difficulty of exactly duplicating the feature -- namely, the fibers in the substrate -- and the utility of the highly robust image analysis of the fiber placement. Furthermore, this feature would not be reproducible using electronic printing and scanning techniques and hence would frustrate nearly all counterfeiters.
|
From page 244... ...
Key Development Risks and Issues: Phase I The durability of this digitally encrypted substrate feature is unknown, but it would depend on the lengths of fiber embedded in the currency as well as on the continued sharpness of the unique image as the banknote became worn. For instance, if the fibers broke or became disbonded from the substrate, the image could change significantly.
|
From page 245... ...
It would require new capital equipment at the BEP. The cost of adding the fibers and signing the note should be approximately the same as that of the current security thread.
|
From page 246... ...
a P at h n e xt g e n e r at i o n U.s. Banknotes to the of Further Reading Chen, Y., M.K.
|
From page 247... ...
aPPendix d ENGINEERED COTTON FIBERS Description The cotton fiber is a complex biological structure engineered by both natural selection and intensive plant breeding. Cotton is the premier natural fiber for textile applications.
|
From page 248... ...
a P at h n e xt g e n e r at i o n U.s. Banknotes to the of • The impossibility of counterfeiting or simulating resulting features by all but state-sponsored counterfeiters.
|
From page 249... ...
aPPendix d epitopes into a single cotton variety or the blending of multiple varieties would create an extremely complex immunoreactive profile for which a complementary mixture of monoclonal antibodies could be generated for law enforcement and other rigorous detection applications. In this latter case, an immunological profile would be generated with sufficient redundancy to make counterfeiting or simulation totally impossible.
|
From page 250... ...
As a result, a situation emerges where key enabling technology -- the gene or genes that encode the trait -- remains unknown. The BEP could control information about, or even patent, the genes for a fiber trait useful for currency production as they are cloned and characterized.
|
From page 251... ...
aPPendix d the FRN. As an example, consider a bacteriorhodopsin-based trait that will deter counterfeiting by exhibiting complex dynamic behavior that is only displayed by these classes of materials (see the following subsection)
|
From page 252... ...
reproduce the effect created in a bona fide FRN via the use of rDNA-based cotton fiber. Key Development Risks and Issues: Phase I It is reasonable to assume that at least some of the useful phenotypes that may be created in a cotton fiber by rDNA technology will be as durable as those dis played by the natural fibers.
|
From page 253... ...
aPPendix d incorporation of a gene that allows the plant to survive the application of the herbicide glyphosate)
|
From page 254... ...
There are many opportunities for features within this technology area, so Phase I activities can determine which potential features are of greatest interest for counterfeit deterrence. Feasibility experiments can be conducted, through a combination of laboratory-based work and modeling and simulation analysis, to select the most promising future directions for currency applications.
|
From page 255... ...
This compatibility issue should be addressed during Phase II of the development process as the BEP updates the substrate material specification. Once the new cotton line is developed, the incremental production cost should be extremely low, less than the cost of the current security thread.
|
From page 256... ...
In particular, one can argue that intrinsic limits in resolution, registration, pattern layouts, and inks associated with printing methods may make it neces sary to consider radically different manufacturing concepts. Through the passive e-substrate feature platform, a fundamentally new approach is examined here that adapts, for the production of currency or currency features that offer no electronic functionality, tools and fabrication facilities principally designed for electronics used in large-area applications, such as liquid-crystal televisions and computer monitors, or low-cost devices, such as RFID tags.
|
From page 257... ...
currency or currency features produced in this fashion. Fifth, the current technology status and future trends in costs, capabilities, and production capacities indicate that this approach to currency production is, for certain implementations such as security strip features, feasible now, with costs that are expected to continue to decrease in the future.
|
From page 258... ...
a P at h n e xt g e n e r at i o n U.s. Banknotes to the of FIGURE D-2 Large-area circuits in the Gen 7 format (see discussion in text)
|
From page 259... ...
The most realistic possibility, as argued subsequently, involves the use of such approaches for the fabrication of new, passive features for conventional printed paper notes, where these features, in the form of narrow strips, are cut from macroelectronic substrates and integrated with the paper using approaches currently employed for digital optically variable devices and security strips. Potential Implementations In the simplest implementation, the patterns formed using the materials and patterning techniques of macroelectronics provide passive features that have a distinct appearance (for overt operation)
|
From page 260... ...
The following discussion is limited to existing, commercial-scale fabrication approaches based on thin-film processing for the passive features. (Some of the same arguments apply to technology options for the electronics and/or interconnects, the active features described in the subsec tion below, "Active e-Substrate.")
|
From page 261... ...
or reflective diffractive optical elements that are at present used in currency. The photoresist masking procedures are applicable to broad classes of other materials that might be considered for currency applications.
|
From page 262... ...
The durability of a passive e-substrate strip would be compa rable to, or better than, that of a diffractive optically variable device (DOVD) or conventional security strip.
|
From page 263... ...
aPPendix d conservative estimates, since many currency implementations (for example, passive images or structures) would require only one or two patterned layers instead of the four to six that are used for circuits.
|
From page 264... ...
. Active e-Substrate Description Active electronic substrates -- that is active e-substrates -- refer to classes of features that, like the passive e-substrate features, are enabled by techniques and materials emerging from developments in large-area and/or low-cost electronics.
|
From page 265... ...
, and piezoelectric cantilevered beams are activated by shak ing. Common piezoelectric materials include quartz and lead zirconate titanate, and polymers are now being developed as piezoelectric elements for microelectromechanical systems (MEMS)
|
From page 266... ...
. • Durability/manufacturing considerations: Monolithic piezoelectric devices are commercially available as rods or cylinders and can be embedded into the banknote in the same way as the current security threads, except now lead wires are required.
|
From page 267... ...
Research should focus on the ability of current technologies to produce devices capable of powering low-power outputs such as LED for currency applications. Scenario c.
|
From page 268... ...
. • Potential research topics: Extensive research is ongoing to improve photo voltaic conversion efficiency and durability.
|
From page 269... ...
aPPendix d Scenario e. Power-Generating Devices: Inductive • Source of energy: Rubbing two ends of the banknote together, or passing the banknote across an external magnet, or shaking the banknote.
|
From page 270... ...
Scenario a. Electronics: Printed Electronics One strategy for forming the electronics component of an active e-substrate feature involves the deposition and patterning of the circuit layers directly on the substrate (for example, plastic for a security strip)
|
From page 271... ...
The newer approaches that use printable semiconductors and other materials are currently not sufficiently well developed for serious consideration for currency applications. Progress in these areas will, of course, potentially change this situation.
|
From page 272... ...
these are close to original sizes. When elarged these low res images will lose some sharpnesswhen printed offset or digital a P at h n e xt g e n e r at i o n U.s.
|
From page 273... ...
aPPendix d FIGURE D-7 Flexible, paperlike displays that integrate electrophoretic inks with printed flexible electronic backplane circuits. The images show (top left)
|
From page 274... ...
For all three of these approaches, the semiconductor is usually single-crystal silicon, although many other materials are possible. Electrical inter connects are typically patterned on the device substrate to interface the elements with one another or with other subsystems such as the power sources described in the previous subsection.
|
From page 275... ...
Costs of the active features could be expected to be ~10 times higher than the simple passive structures, when fabricated with thin-film processing techniques. An attractive alternative manufacturing approach for the active features could exploit the integration of small-scale chips of processed single-crystal silicon, similar to those elements used in RFID tags, as described in the previous subsection.
|
From page 276... ...
• Analytically demonstrate the required power generation. Estimate of Implemented Production Cost The costs for an active e-substrate feature are difficult to estimate.
|
From page 277... ...
Pittsburgh, Pa.: Materials Research Society. Materials Research Society Symposium Proceedings, Vol.
|
From page 278... ...
Three phenomena based on the thermoelasic martensite have potential for currency security features: • Shape memory effect (SME) -- in which deformed structures are recovered with heating.
|
From page 279... ...
The active nature of features based on thermoelastic martensite features would be a strong deterrent to currency counterfeiting for all but the most sophisticated counterfeiters sponsored by national governments. Primitive, hobbyist, and petty criminal counterfeiters would be hard-pressed to simulate the active response combined with the metallic nature of the features.
|
From page 280... ...
Likewise, because many currencies currently include holographic foils, one would expect to be able to integrate NiTi foils readily into notes. Simulation Strategies Primitive and opportunist counterfeiters would not be able to duplicate and would have a very difficult time simulating the effects of thermoelastic alloy fea tures.
|
From page 281... ...
Processing bulk alloys to the thin foils required for currency applications requires precise thermal mechanical processing and high-strength rolling mills. Direct production of thin foils using sputtering and other approaches is currently being carried out in the laboratory but will require technological advances for production scale-up to provide the proper chemistry control in conjunction with the large volume necessary for full-rate currency production.
|
From page 282... ...
Direct sputtering of thin foils is complicated by the difficulty in controlling and reproducing exact alloy stoichiometries, owing either to uneven sputtering rates of Ni and Ti from alloy targets or to uneven spatial distribution from single-component targets, if co-sputtering is used. A number of university and industrial programs continue to develop NiTi thin-film technology.
|
From page 283... ...
1990. Engineering Aspects of Shape Memory Alloys.
|
From page 284... ...
Many research programs in smart nanomaterials have targeted the use of extremely high technology manufacturing systems to create materials capable of independent dynamic responses. The final output of these responses may be both human-perceptible (detected by simple bioassay)
|
From page 285... ...
is being explored as a manufacturing base for the large-scale industrial processing of consumer items such as computer chips and scaffolds for bioengineering applications like in vitro tissue and organ growth. Large-scale industrial demand for MSA/MM-based facilities may bring the cost security features using the same technology into line with the economic constraints of FRN production the near future.
|
From page 286... ...
The result is posited to be a human-perceptible phenomenon easily and rapidly recognized by the targeted class of users. The usefulness of such a feature is that it recaptures the ease of counterfeit detection inherent in the macroscopic optical security features of FRNs prior to the commercialization of cheap yet sophisticated reprographic products.
|
From page 287... ...
In addition, novel organic-in organic hybrid nanocomposites, consisting of nanoparticles and formed using simple dip processing methods that combine sensing and reactive components.17 While the goal of this work is to develop smart nanomaterials that can act as reactive or responsive protective coatings for fibers and fabrics for soldier technologies, any material that can exhibit "dynamic, reversible behavior" that is humanperceptible (that is, may be bioassayed) is obviously a candidate for a security feature in currency.
|
From page 288... ...
Key Development Risks and Issues: Phase I Smart nanomaterials comprise an emerging area, and a number of possible features can be imagined. The adaptation of the nanomaterials work to counterfeit deterrent features leverages ongoing programs.
|
From page 289... ...
A number of different directions could be pursued. It is possible that this technology could be implemented at some future time for less cost than that of the current security thread.
|
From page 290... ...
At the present time, it is not clear if tactilely active piezoelectric features can be practically integrated into notes. Such features will require significant development to integrate them effectively into notes with electronic substrates.
|
From page 291... ...
Currency users could readily detect shape changes and changes in the tactile nature of the features. Denomination-specific placement and patterning of the features would allow simple identification of the note values, making such features very useful for visually impaired users.
|
From page 292... ...
More complex integration into a note would include patterns of either EAPs or piezoelectric crystals that would change local topography on the note with the voltage applied. This patterning could be designed to produce recognizable effects such as buildings, eagles, or numbers specific to the denomination, as illustrated in Figure D-8.
|
From page 293... ...
The changes in tactile nature on the note would be a function of a number of BEP- or supplier-controllable variables, including electroactive material, dot size, and coating. Primitive, opportunist, and petty criminal counterfeiters would not be able to simulate this active change in tactile response accurately.
|
From page 294... ...
The proper patterning and integration with the appropriate leads and power supplies would require processing beyond the realm of all but professional criminal or state-sponsored counterfeiters. Primitive and opportunist counterfeiters would not be able to duplicate and would have a very difficult time simulating the active response of EAPs.
|
From page 295... ...
At that point the effectiveness of the active changes in shape and tactile nature could be assessed. Estimate of Implemented Production Cost This technology is very immature for currency applications, and thus an analysis of the implementation cost should be included as part of the development program during Phase I
|
From page 296... ...
Cohen, J.Y. Electroactive Polymers as Artificial Muscles -- A Primer.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.