Helical oligomer and polymer compositions that form nanotubes are described. The compositions comprise a plurality of aromatic substituents linked by at least one amide group. The compositions have a curved backbone due to intramolecular hydrogen bonds that rigidify the amide linkage of each amide group to each aromatic substituent and due to an interaction between the aromatic substituents such that the curved backbone is stabilized. The helical compositions are formed by ridigifying the amide group, which is flanked on each side by the aromatic substituents, by introducing intramolecular hydrogen bonds into a linkage between the amide group and each aromatic substituent such that the compositions fold into a helical shape when the amide linkages are meta to each other.

Naturally occurring membrane channels and pores are formed from a large family of diverse proteins, peptides and organic secondary metabolites whose vital biological functions include control of ion flow, signal transduction, molecular transport and production of cellular toxins. (Eisenberg, B. (1998) Ionic channels in biological membranes: natural nanotubes. Acc. Chem. Res. 31:117; Hill, B. (1992) Ionic Channels of Excitable Membranes 2nd edn. (Sinauer Associates, Sunderland); Gennis, R. B. (1989) Biomembranes, Molecular Structure and Function, Springer, New York). Many pore-forming peptides, such as gramicidin and alamethicin, function by creating pores within the plasma membrane of a target cell (Marsh, D. (1996) Peptide models for membrane channels. Biochem. J. 315(pt2):345; Smart, O. S.; Goodfellow, J. M.; Wallace, B. A. (1993) The pore dimensions of gramicidin A. Biophys. J. 65(6):2455; Ritov, V. B.: Tverdislova, I. L.; Avakyan, T. Yu; Menshikova, E. V.; Leikin, Yu N.; Bratkovskaya, L. B.; Shimon, R. G. (1992) Alamethicin-induced pore formation in biological membranes. Gen. Physiol. Biophys. 11(1):49). Pore-forming protein toxins, such as the Staphylococcus aureus xcex1-hemolysin and Streptococcus streptolysin-O, act similarly by boring holes into the cell membranes. (Bayley, H. (1997) Toxin structure: part of a hole? Curr. Biol. 7(12):R763; Ikigai, H.; Nakae, T. (1987) Assembly of the alpha-toxin-hexame of Staphylococcus aureus in the liposome membrane. J. Biol. Chem 262:2156; Palmer, M; Vulicevic I.; Saweljew, P.; Valeva, A.; Kehoe, M.; Bhakdi, S. (1998) Biochem. 37(8):2378. Streptolysin-O: a proposed model of allosteric interaction between a pore-forming protein and its target lipid bilayer. xcex1-Hemolysin has received intense interest as a prototype for artificial molecular gatekeepers that can be used for the design of drugs, (Bayley, H. (1997) Building doors into cells. Sci. Am. 277 (September):62); (Panchal, R. G.; Cusak, E.; Cheley, S.; Bayley, H. (1996) Turnor-protease-activated, pore-forming toxins from a combinatorial library, Nature Biotechnol 14:852) drug delivery agents (Fernandex, T.; Bayley, H. (1998) Ferrying proteins to the other side. Nature Biotechnol. 16(5):418) or highly sensitive and selective biosensors. (Braha, O.; Walker, B.; Cheley, S.; Kasianowicz, J. J.; Song, L.: Gouaux, J. E.; Bayley, H. (1997) Designed protein pores as components for biosensors. Chem. Biol. 4:497). Difficulties associated with using protein molecules in these designs include heat and mechanical instability, immunogenicity in biotherapeutics, and the like.
Lying at the center of the pore assembled from seven molecules of xcex1-hemolysin (and many other pore-forming proteins) is a nanosize channel. (Song, L; Hobaugh, M. R.; Shustak, C.; Cheley, S.; Bayley, H.; Gouaux, J. E. (1996) Structure of Staphylococcal xcex1-hemolysin, a heptameric transmembrane pore. Science 274:1859). The transmembrane segment, a xcex2-barrel, of the channel ranges from 14 xc3x85 to 26 xc3x85 in diameter and 52 xc3x85 in length. The interior of the xcex2-barrel was found to be primarily hydrophilic, while the exterior has a hydrophobic belt.
Despite the existence of numerous chemical models as artificial transmembrane channels, (Alkerfeldt, K. S.; Lear, J. D.; Wasserman, Z. R.; Chung, L. A.; DeGrado, W. F. (1993) Acc. Chem. Res. 26:191; Gokel, G. W.; Murillo, O. (1996) Acc. Chem. Res. 29:425) the design and synthesis of artificial systems that can mimic the biological function of natural compounds is still a formidable task. A successful model rivaling the structural robustness and versatility as observed in the natural systems has not been seen until the present invention. Such a model requires a tube-or barrel-like structure with a nanosized, hydrophilic internal cavity and a hydrophilic internal cavity and a hydrophobic outside surface.
The self-assembly of cyclic peptides (Ghadiri, M. R.; Granja, J. R.; Milligan, R. A.; McRee, D. E.; Khazanovich, H. (1993) Self-assembling organic nanotubes based on a cyclic peptide architecture. Nature 366:324) provides an example of self-assembling nanotubes. However, Ghadiri""s nanotubes do not suit the above purpose since these tubes consist of stacked peptide rings. Due to the structure of these cyclic peptides and the way the tubes form, it is difficult to imagine how different molecular switches could be put site-specifically into these nanotubes.
Other approaches have been described (Bryson, J. W.; Betz, S. F; Lu, H. S.; Suich, D. J.; Zhou, H. X.; O""Neil, K. T.; DeGrado, W. F. (1995) Protein design: a hierarchic approach. Science 270:935) toward manipulating nanoscale structures by designing oligomeric bundles of xcex1-helices. Models for transmembrane helical oligomers may lead to simplified systems for designing pore-forming agents. (Dieckmann, G. R.; DeGrado, W. F. (1997) Modeling transmembrane helical oligomers Curr. Opin. Struct. Biol. 7(4):486). The advantage of these helix bundles is that they allow precise control over the positions to be modified, enabling site-specific engineering of the nanostructures with both natural and unnatural amino acids. However, one disadvantage of these designed helix bundles is that they may have the same instability and immunogenicity problems associated with natural peptides and proteins.
Until the present invention, a question that still remained was whether unnatural systems provide nanosize, tube-like structures. Various prior art approaches to folding structures have been taken, involving primarily the use of intramolecular hydrogen bonding, or donor-acceptor interactions. (Gellman, S. H. (1998) Foldamers: a manifesto. Acc. Chem. Res. 31:173) Examples of folded, potentially functionalizable structures include xcex2-peptides and peptoid oligomers and many others involving unnatural backbones. (Appella, D. H; Christianson, L. A.; Karle, I. L; Powell, D. R.; Gellman, S. H. (1996) Beta-Peptide foldamers: robust helix formation in a new family of beta-amino acid oligomers. J. Am. Chem. Soc. 118:13071-13072; Seebach, D.; Overhand, M.; Kuhnle, F. N. M.; Martinoni, B.; Oberer, L.; Hommel, U.; Widmer, H. (1996) Beta-Peptides: synthesis by Arndt-Eistert homologation with concomitant peptide coupling. Structure determination by NMR and CD spectroscopy and by X-ray crystallography. Helical secondary structure of a xcex2-hexapeptide in solution and its stability towards pepsin. Helv. Chim. Acta 79:913; Armand, P.; Kirshenbaum, K.; Falicov, A.; Dunbrack, R. L. Jr.; Dill, K. A.; Zuckermann, R. N.; Cohen, F. E. (1997) Chiral N-substituted glycines can form stable helical conformations. Fold. Des. 2(6):369; and others such as Cho, C. Y.; Moran, E. J.; Cherry, S. R.; Stephans, J. C.; Fodor, S. P.; Adams, C. L.; Sundaram, A.; Jacobs, J. W.; Schultz, P. G. (1993) An unnatural biopolymer, Science 261:1303). However, few examples have shown folded structures with cavities similar to those seen in protein molecules.
One approach toward building nanotubes involved designing oligomers that undergo polar solvent-driven folding (Nelson, J. C.; Saven, J. G.; Moore, J. S.; Wolynes, P. G. (1997) Solvophobically driven folding of nonbiological oligomers. Science 277:1793). While a helical conformation with nanosized tubular cavity was proposed for the folded structure, this system was, however, unsuitable for designing pore-forming agents since the interior is quite hydrophobic.
The assembly of well-defined protein secondary structures, such as xcex1-helix, xcex2-sheet, and turns, leads to a bewildering array of tertiary structures. (Branden, C.; Tooze, J., Introduction to Protein Structure, 2nd ed.; Garland Publishing: New York, 1998). As the first step toward developing artificial oligomers and polymers that fold like biomacromelecules, there is currently an intense interest in designing unnatural building blocks that adopt well-defined secondary structures. (Gellman, S. H., Acc. Chem. Res., 1998, 31, 173; Appella, D. H.; Christianson, L. A.; Karle, I. L.; Powell, D. R.; Gellman, S. H., J. Am. Chem. Soc., 1999, 121, 6206. Gong, B.; Yan, Y.; Zeng, H.; Skrzypcak-Jankun, E.; Kim, Y. W.; Zhu, J.; Ickes, H., J. Am. Chem. Soc., 1999, 121, 5607. Gin, M. S.; Yokozawa, T.; Prince, R. B.; Moore, J. S., J. Am. Chem. Soc., 1999, 121, 2643. Yang, D.; Qu, J.; Li, B.; Ng, F.-F; Wang, X.-C.; Cheung, K.-K.; Wang, D.-P; Wu, Y.-D., J. Am. Chem. Soc., 1999, 121, 589. Hanessian, S.; Luo, X.; Schaum, R.; Michnick, S., J. Am. Chem. Soc., 1998, 120, 8569. Seebach, D.; Abele, S.; Stifferlen, T.; Hanggi, M.; Gruner, S.; Seiler, P., Helv. Chim. Acta, 1998, 81, 2218. Armand, P.; Kirshenbaum, K.; Goldsmith, R. A.; Farr-Jones, S.; Barron, A. E.; Truong, K. T.; Dill, D. A.; Mierke, D. F.; Cohen, F. E.; Zuckermann, R. N.; Bradley, E. K., Proc. Natl. Acad. Sci. U.S.A., 1998, 95, 4309).
This invention relates to a novel class of compositions such as oligomers and polymers that automatically fold into helices with large (10 xc3x85 to 50 xc3x85) tubular cavities. The compositions are comprised of aromatic rings linked by amide groups. The backbone of the composition is curved due to the incorporation of intramolecular hydrogen bonds that rigidify the amide linkages. The backbone is long enough to fold back on itself, leading to a left- or right-handed helical conformation.
The helical composition is further stabilized by stacking of the aromatic rings of neighboring spiral turns. Such a backbone-based helical programming leads to helical compositions whose folded conformation is resilient toward structural variation of the side groups which, in turn, determine the outside surface properties. The interior of the helical composition features the amide-O atoms, which make the tubular cavities hydrophilic. The internal diameters of the helices are adjustable by combining meta- and para-disubstituted benzene rings or by using larger aromatic rings, such as derivatives of naphthalene and anthracene.
These helices, as nanotubes, are useful as artificial pore-forming agents which are readily functionalized. Molecular gatekeepers based on these nanotubes are designed by including biochemical, chemical, and physical switches into the structures. The present invention is especially useful for design of pore-forming drugs, drug carriers, novel chiral hosts for chiral recognition and catalysis, and sensitive membrane-bond ion-channels and sensors.
The helical compositions of present invention are also useful as pore-forming drugs, membrane-bound nanopores for DNA sequencing, and new optical materials.
The present invention also relates to methods for making nanotube compositions and the nanotube compositions themselves. These nanotube compositions mimic part or all of the pore-forming function of xcex1-hemolysin and other similar proteins. Artificial pores that behave in a controlled and predictable fashion are synthesized according to the present invention. These nanotube compositions are useful as drugs, to deliver drugs or as biosensors to detect toxic chemicals.
The compositions have a nanosized barrel- or tube-like structure with a hydrophilic interior and a hydrophobic exterior. To avoid the problems associated with protein molecules, the nanotube compositions have mechanical and heat stability for designing sensors and other materials, or are biologically inert (enzyme resistant and non-immunogenic) in biotherapeutics. To control the pore""s ability to open and close, the nanotube compositions are readily modifiable to enable molecular switches to be incorporated into one or more specific sites.
The present invention also relates to new nanotube compositions based on the folding of designed oligomers. These nanotube compositions satisfy all the requirements, as defined above, for designing pore-forming agents, for the design of various desirable functional agents.
The present invention provides well-defined, folded conformations through rigidification of backbones. The conformations have (i) electrostatically negative, hydrophilic interior cavities; (ii) modifiable exterior surfaces; and (iii) adjustable cavity size.
In one aspect of the present invention, the conformations are useful for transmembrane channels and pores.
In this aspect, the following applications are particularly useful:
(i) Synthesis of Compositions: monomers with membrane-compatible side groups (selected xcex1-amino acid side chains); sequence-specific synthesis of oligomers on solid-supports.
(ii) Characterization of Compositions: x-ray crystallography; 1D and 2D NMR; IR; facilitated by sequence information from synthesis.
(iii) Membrane studies: liposome-based proton transport; single channel conductance measurements; hydrophilic (sugar or dye) molecule transport; nanotube orientation in lipid bilayer as probed by polarized attenuated total reflectance (ATR), grazing-angle reflection-absorption, and FT-IR spectroscopy.
(iv) Gated nanotubes with physical or biochemical switches.
(v) Cytotoxicity assays (with the oligomers alone or with drug transport).
Still other applications include: (i) Channel- and pore-forming reagents (toxins), (ii) ion- and small molecule-transport (drug delivery), and (iii) Gated pore- and channels, and (controlled drug delivery and cell-based sensors).
In another aspect of the present invention, the conformations are useful as nanoporous polymers. In this aspect, the following applications are particularly useful
(i) Synthesis of Compositions: monomers with hydrophobic and cross-linkable side chains; polymerization of monomers (mostly one-pot); block copolymers with polymerization of short oligomers.
(ii) Characterization of Compositions: gel permeation chromatography; light scattering; IR and UV (intramol. H-bonds; hypochromic effects of stacked aromatic ringsxe2x80x94folding of polymers).
(iii) Formation of polymer films: by simple casting, and by solid- and liquid-phase, lateral cross-linking of polymer chains (oxidation, metathesis, and lateral polymerization).
(iv) Permeate flux and solute selectivity of the porous materials.
(v) Confinement and parallel alignment of close-packed guest molecules in bulk polymeric materials. Binding of guest molecules into the tubular cavities (probed by affinity columns and/or by fluorescence quenching); nanowires from reduction of metal ions absorbed into the tubular cavities.
Still other applications include: (i) polymer films with a single pore size: highly efficient materials for separation and purification; (ii) tubular cavities for aligning interesting chromophores: electro-optic materials with the robustness of polymers and the flexibility of host-guest interactions; and, (iii) templates for the fabrication of conducting nanowires.

Helices and nanotubes on folding compositions and method of making same


A rod-shaped semiconductor device having a light-receiving or light-emitting function is equipped with a rod-shaped substrate made of p-type or n-type semiconductor crystal, a separate conductive layer which is formed on a part of the surface of the substrate excluding a band-shaped part parallel to the axis of the substrate and has a different conduction type from the conduction type of the substrate, a pn-junction formed with the substrate and separate conductive layer, a band-shaped first electrode which is formed on the surface of the band-shaped part on the substrate and ohmic-connected to the substrate, and a band-shaped second electrode which is formed on the opposite side of the first electrode across the shaft of said substrate and ohmic-connected to the separate conductive layer.

The inventor of the present application proposed, in U.S. Pat. No. 6,204,545, a spherical semiconductor element which has a light-receiving or light-emitting function, wherein a spherical pn-junction is formed near the surface of a spherical semiconductor crystal, and dot-shaped positive and negative electrodes are formed at both ends across the center of the spherical crystal. The semiconductor element has optical symmetry in other directions than the axial direction connecting the pair of electrodes, and has the advantage that it can receive light three-dimensionally from various directions and emit light three-dimensionally in various directions.
The inventor of the present application proposed, in International Laid-Open Patent Application WO03/017382, a spherical semiconductor device which is nearly the same semiconductor element as said semiconductor element, wherein one electrode is formed on a flat surface with a part of an apex of a spherical semiconductor crystal removed, and the other electrode is formed on the opposite side of the electrode across the center of the semiconductor crystal.
A light-receiving or light-emitting module is obtained by arranging such spherical semiconductor elements in a planar matrix form with many rows and columns, serially connecting multiple semiconductor elements in each column, and connecting in parallel multiple semiconductor elements in each row. The larger the light-receiving area or light-emitting area of the module is made, the larger the number of connecting points at which the semiconductor element is electrically connected becomes.
The inventor of the present application proposed, in International Laid-Open Patent Application WO02/35612, a spherical semiconductor device which is nearly the same semiconductor element as said semiconductor element, wherein a pair of flat surfaces are formed by removing both ends across the center of a spherical semiconductor crystal, a pn-junction is formed near the surface including one flat surface of the semiconductor crystal, and positive and negative electrodes are formed on the one flat surface and the other flat surface.
In addition, proposed in International Laid-Open Patent Application WO02/35612 is a rod-shaped semiconductor element which has a light-receiving or light-emitting function, wherein a pair of end surfaces is formed perpendicular to the shaft on a columnar semiconductor crystal, a pn-junction is formed near the surface of the semiconductor crystal including one end surface, and positive and negative electrodes are formed on both of the end surfaces. The rod-shaped semiconductor element has an optical symmetry in other directions than the axial direction connecting the pair of electrodes, and has an advantage that it can receive light three-dimensionally from various directions and emit light three-dimensionally in various directions.
In the photovoltaic array described in U.S. Pat. No. 3,984,256, an n-type diffusion layer is formed on the surface of a filament made of p-type silicon semiconductor of 0.001˜0.010 inches in diameter, a plural number of this filament are arranged in parallel and in a planar form, multiple P-connection line members and N-connection line members are alternately placed orthogonally on the top of these filaments, the P-connection line member is ohmic-connected to the exposed part of the p-type silicon semiconductor of multiple filaments, the N-connection line member is ohmic-connected to the n-type diffusion layer of multiple filaments, multiple P-connection line members are connected to a P bus, and multiple N-connection line members are connected to an N bus. An insulating fiber with a superior strength is woven in so as to constitute multiple P buses and N buses and a mesh, thus constituting a flexible solar battery blanket which generate electricity by receiving incident light from its top surface.
In the semiconductor fiber solar battery and module described in U.S. Pat. No. 5,437,736, a molybdenum conductive layer is formed on the surface of an insulating fiber, two layers of p-type and n-type thin-film semiconductor layers having a photovoltaic function and a ZnO conductive layer are formed on approximately ⅗ of the periphery of the surface of this conductive layer, a plural number of these semiconductor fiber solar batteries are arranged in parallel and in a planar form, a metal coating is formed on its backside, after which the metal coating is partially removed in a specified pattern, thus forming a connection circuit which performs tasks such as serially connecting multiple semiconductor fiber solar batteries.
Patent Document 1: U.S. Pat. No. 6,204,545.
Patent Document 2: International Laid-Open Patent Application WO03/017382.
Patent Document 3: International Laid-Open Patent Application WO02/35612.
Patent Document 4: U.S. Pat. No. 3,984,256.
Patent Document 5: U.S. Pat. No. 5,437,736.
In manufacturing a solar battery panel using spherical semiconductor elements, a near-spherical semiconductor elements with a flat surface formed on a part of each, or near-spherical semiconductor elements with a pair of flat surfaces formed, the number of connecting points which electrically connect the semiconductor elements increases, the structure of a conductive connection mechanism which electrically connects the semiconductor elements becomes complex, and its manufacturing cost increases.
Because said rod-shaped semiconductor element also has a granular shape, in manufacturing a solar battery panel, the number of connecting points which electrically connect the semiconductor elements increases, the structure of a conductive connection mechanism which electrically connects the semiconductor elements becomes complex, and its manufacturing cost increases.
Furthermore, because a pair of electrodes are formed on both end surfaces perpendicular to the shaft, if the length of the rod-shaped semiconductor element is made large, the distance between the positive and negative electrodes increases, and the electrical resistance between the positive and negative electrodes increases. Therefore, the rod-shaped semiconductor element is not fit for manufacturing a semiconductor element having a length multiple times that of the diameter.
Because the photovoltaic array described in U.S. Pat. No. 3,984,256 has a construction wherein light enters from the top in the same manner as solar battery panels installed near-horizontally, it cannot receive light entering from both sides of the panel. This is also true with the semiconductor fiber solar battery in U.S. Pat. No. 5,437,736.
Especially, in a solar battery panel embedded in a window glass for example, it is desired that it be able to receive light from both sides. On the other hand, in constructing a light-emitting panel with semiconductor elements having a light-emitting function, it is desirable that light can be emitted to both sides of the panel.
Objectives of the present invention include providing a rod-shaped semiconductor element which has a light-receiving or light-emitting function and can increase the light-receiving area without increasing the inter-electrode distance, providing a rod-shaped semiconductor element which has a large length/diameter ratio and can reduce the number of electrical connecting parts in making a panel of multiple semiconductor elements, providing a rod-shaped semiconductor element which is hard to roll, providing a rod-shaped semiconductor elements wherein polarity of each electrode is easy to identify, and so on.
The rod-shaped semiconductor device of the present invention, having a light-receiving or light-emitting function, comprises a rod-shaped substrate made of p-type or n-type semiconductor crystal having a circular cross section or near-circular cross section, a separate conductive layer which is formed on a part of a surface of the substrate excluding a band-shaped part parallel to an axis of the substrate and has a different conduction type from that of the conduction type of the substrate, a near-cylindrical pn-junction formed with the substrate and the separate conductive layer, a band-shaped first electrode which is ohmic-connected to a surface of the band-shaped part of the substrate, and a band-shaped second electrode ohmic-connected to the separate conductive layer on an opposite side of the first electrode across the axis of the substrate. The separate conductive layer may be formed by diffusion, film formation, or ion injection.
If the rod-shaped semiconductor device has a light-receiving function, when sunlight is received, it generates a photovoltaic power of a specified voltage by its pn-junction, and outputs it between the first and second electrodes. Because it has a light-receiving symmetry about a plane which includes the first and second electrodes, light beams entering from both sides of the plane are received to generate electric power. If a large number of rod-shaped semiconductor devices are arranged in a panel shape and a circuit to extract the output is formed, it becomes a solar battery panel (solar battery module).
If the rod-shaped semiconductor device has a light-emitting function, when a specified voltage is applied between the first and second electrodes, light corresponding to the band-gap energy from the pn-junction is emitted from the pn-junction. If a large number of rod-shaped semiconductor devices are arranged in a panel shape and a circuit to apply a voltage is formed, it becomes a light-emitting panel (light-emitting module).
According to the rod-shaped semiconductor device of the present invention, because band-shaped first and second electrodes connected to the surface of a band-shaped part of a rod-shaped substrate and a separate conductive layer are installed, even when the length/diameter ratio of the substrate is increased, the distance between the first and second electrodes can be maintained smaller than the diameter of the substrate, and the electrical resistance between the first and second electrodes can be maintained small. Therefore, power generating performance or light-emitting performance in the pn-junction can be maintained high.
As a result, in constructing a light-receiving or light-emitting panel, the light-receiving area of each semiconductor device is increased by increasing the length/diameter ratio of the substrate, and the number of electrical connecting parts for wiring the semiconductor devices can be decreased, making it possible to improve the reliability of the panel and reduce the manufacturing cost. Furthermore, because there is a light-receiving or light-emitting symmetry about a plane including the first and second electrodes, it is possible to construct a light-receiving panel which can receive light from both sides of the panel or a light-emitting panel which can emit light from both sides of the panel.
As the constitutions of dependent claims of the present invention, various kinds of constitutions such as the following may be adopted.
(1) A band-shaped apex of the substrate is removed to form a band-shaped flat surface, and on this flat surface the band-shaped part is formed, not only making it a rod-shaped semiconductor element which is hard to roll, but also making it possible to easily identify the polarities of the first and second electrodes.(2) An antireflective film is formed on a part of the surfaces of the substrate and separate conductive layer excluding the first and second electrodes.(3) The substrate is made of p-type Si single-crystal or Si polycrystalline, and the separate conductive layer is made of an n-type conductive layer containing P, Sb, or As.(4) The substrate is made of n-type Si single-crystal or Si polycrystalline, and the separate conductive layer is constituted of a p-type conductive layer containing B, Ga, or Al.(5) The device is constructed to be a light-receiving device which receives light and generates electricity.(6) The substrate is made of n-type GaP single crystal or GaAs single crystal, and the separate conductive layer is constituted of an n-type diffusion layer wherein Zn is thermally diffused, which constitutes a light-emitting diode.(7) The substrate is made of n-type GaAs single crystal, and the separate conductive layer is formed by diffusion, film-forming, or ion-injection of p-type GaAs, which constitutes a light-emitting diode.(8) The substrate is made of n-type SiC single crystal, and the separate conductive layer is formed by forming a p-type GaN, GaInP, or P film, which constitutes a light-emitting diode.(9) The area of the pn-junction is set larger than the area of a cross section perpendicular to the axis of the substrate.


A system can obtain a labelled data set, including historic video data and labelled events. The system can divide the labelled data set into historic training/testing data sets. The system can determine, using the historic training data set, a plurality of different parameter configurations to be used by a video encoder to encode a video that includes a plurality of video frames. Each parameter configuration can include a group of pictures (“GOP”) size and a scenecut threshold. The system can calculate an accuracy of event detection (“ACC”) and a filtering rate (“FR”) for each parameter configuration. The system can calculate, for each parameter configuration of the plurality of different parameter configurations, a harmonic mean between the ACC and the FR. The system can then select a best parameter configuration of the plurality of different parameter configurations based upon the parameter configuration that has the highest harmonic mean.

According to a 2015 report on the installed base for video surveillance equipment, there is a camera installed for every 29 people on Earth. Video analytics from these cameras are used for traffic control, retail store monitoring, surveillance and security, as well as consumer applications such as digital assistants for real-time decisions. One of the major problems in video analytics is deciding which parts of the video are critical to a real-time decision. For example, a security camera that is watching a parking lot for 24 hours per day will typically have only a few frames that show a potential risk of theft or damage. A camera that captures 30 frames per second ("fps") can record more than 2.5 million frames per day and processing this massive amount of data is prohibitively expensive.

Data-driven event detection for compressed video


A photographic camera (10) that generates still photographs or images of a scene by detecting millimeter-wave radiation (16). The camera (10) includes an imaging lens (14) that collects the millimeter-wave radiation (16) and focuses the radiation on a plurality of receiver modules (32) positioned in the focal point of the lens (14) where each receiver module (32) includes a plurality of direct detection millimeter-wave receivers (36). In one embodiment, the plurality of receiver modules (32) are mounted on a single sensor card (28), where the receiver modules (32) on the card (28) are aligned in one direction. Each receiver (36) includes detector circuitry that detects the radiation of a pixel in the scene. Electrical signals from the receiver modules (32) are sent to a processing unit (38) on the sensor card (28). In one embodiment, the radiation (16) collected by the lens (14) is directed to a scanning mirror (18) that scans across the scene at a predetermined rate to generate the entire image. Alternately, the sensor card (28) can be moved relative to the mirror (18) to provide scanning of the image.

1. Field of the Invention
This invention relates generally to a millimeter-wave imaging device and, more particularly, to a photographic camera that provides photographs of a scene by generating still images from detecting millimeter-wave radiation.
2. Discussion of the Related Art
Imaging systems that generate images of a scene by detecting background millimeter-wave radiation (30-300 GHz) given off by objects in the scene offer significant advantages over other types of imaging systems that provide imaging by detecting visible light, infrared radiation, other electro-optical radiation. These advantages generally relate to the fact that millimeter-wave radiation can penetrate low visibility and obscured atmospheric conditions caused by many factors, such as clouds, fog, haze, rain, dust, smoke, sandstorms, etc., without significant attenuation, as would occur with the other types of radiation mentioned above. More particularly, certain propagation windows in the millimeter-wavelength spectrum, such as W-Band wavelengths at about 89 to 94 GHz, are not significantly attenuated by the oxygen and water vapor in air. Millimeter-wave radiation is also effective in passing through certain hard substances, such as wood and drywall, to provide imaging capabilities through walls. Thus, millimeter-wave imaging systems are desirable for many applications, such as aircraft landing, collision avoidance and detection systems, detection and tracking systems, surveillance systems, etc. Virtually any type of imaging system that can benefit by providing quality images under low visibility conditions could benefit by using millimeter-wave imaging.
Recent millimeter-wave imaging systems also can offer the advantage of direct detection. This advantage has to do with the fact the millimeter-wave receivers can include components that amplify, filter and detect the actual millimeter-wavelength signals. Other types of imaging system receivers, such as heterodyne receivers, generally convert the received radiation from the scene to intermediate frequencies prior to detection. Therefore, direct detection millimeter-wave receivers that detect the millimeter-wave radiation do not suffer from the typical bandwidth and noise constraints resulting from frequency conversion and do not include the components needed for frequency conversion.
Millimeter-wave imaging systems that use a focal plane imaging array to detect the millimeter-wave radiation and image a scene are known in the art. In these types of systems, the individual receivers that make up the array each includes its own millimeter-wave antenna and detector. An array interface multiplexer is provided that multiplexes the electrical signals from each of the receivers to a processing system. A millimeter-wave focal plane imaging array of this type is disclosed in U.S. Pat. No. 5,438,336 issued to Lee et al., titled "Focal plane Imaging Array With Internal Calibration Source." In this patent, an optical lens focuses millimeter-wave radiation collected from a scene onto an array of pixel element receivers positioned in the focal plane of the lens. Each pixel element receiver includes an antenna that receives the millimeter-wave radiation, a low noise amplifier that amplifies the received millimeter-wave signal, a bandpass filter that filters the received signal to only pass millimeter-wave radiation of a predetermined wavelength, and a diode integration detector that detects the millimeter-wave radiation and generates an electrical signal. The signal from each of the diode detectors is then sent to an array interface unit that multiplexes the electrical signals to a central processing unit to be displayed on a suitable display unit. Each pixel element receiver includes a calibration circuit to provide a background reference signal to the detector. Other types of focal plane imaging arrays including separate detecting pixel elements are also known in the art.
All of the known millimeter-wave imaging systems generate video images that include consecutive frames of video data displayed in a series. Such video millimeter-wave imaging systems have a wide range of use for many different applications, as mentioned above and discussed in the prior art. What is not suggested in the art is a millimeter-wave imaging system that generates still images of a scene, such as a photograph produced by a single lens reflex (SLR) camera that images visible light. There exists a need in the art to provide such a still image millimeter-wave photographic camera, which would be far less expensive than an equivalent video camera. It is therefore an object of the present invention to provide such a camera.

Millimeter wave instant photographic camera


The identification system operates by the contactless, inductive transmission of information via oscillatory circuits coupled by an electromagnetic field. Excitation is produced by pulses representing the information; the pulse response is utilized. The associated apparatus has one or more pairs of oscillatory circuits (A1/B1;A2/B2;A3/B3) and means (21, 22, 23) for processing the pulse response. A position recognition process transmits test information which is used for the sequential short-circuiting of an oscillatory circuit on the receiver side. This oscillatory circuit behaves like a damped/undamped body as a function of the test function. The partner oscillatory circuit on the transmitter side is excited at, for example, twice the frequency of the test frequency and its pulse response contains the test function through the defined damping behaviour. If the test function is again recognized as a result, the connection is correct and write or read operation is released. If the switch is operated not with a test function, but with a switching sequence of electric values representing data from a store, excitation produced in the partner oscillatory circuit by an interrogation coil can produce a pulse response which contains the data from the store.

It is the object of identification systems to bring articles of any kind together in place and time transiently to form a systematic whole. To this end as a rule the articles are provided with a code carrier, code readers or rather code announcers being located at predetermined places to-determine on the one hand the article itself (identification) and on the other hand its time and place (location). The systematic whole is obtained by bringing these "announcements" together for data processing by data processing means.
Generally the code is transmitted in a contactless manner, for example, by optical or electromagnetic transmission processes, the main problem being to achieve complete, reliable code transmission, if necessary in the shortest possible time. Positioning errors of the code carrier in front of the code reader lead to deficient reading speeds or altogether faulty performance, so that the positioning and recognition of the correct position of a code carrier in front of a read-write location is one of the basic preconditions for the operation of an identification system.

Identification system having a plurality of devices for reading, writing and recognizing a code and a plurality of code carriers and associated process


A dry sump oil tank assembly for a vehicle is provided with a housing defining an internal cavity. The housing is configured with a laterally-extending portion to add lateral volume to the internal cavity and has at least one internal baffle attached to the housing within the internal cavity below the laterally-extending portion and configured to reduce sloshing of oil within the cavity. The dry sump oil tank assembly is particularly useful for high performance applications, such as racing vehicles, and may utilize components from standard vehicle applications, thus maximizing the economies of scale of producing such components and being suited for a vehicle that may be typically used in standard driving conditions, but occasionally subjected to high performance use.

Lubrication systems for internal combustion engines on passenger vehicles may be wet or dry sump lubrication systems. A wet sump lubrication system is typically used on production vehicles. Lubricant is stored beneath the crankshaft and oil pan. The oil pan needs to be large and deep in order to hold sufficient amounts of lubricant, such as oil, to lubricate the engine.
Dry sump lubrication systems utilize an external tank to store some of the oil outside of the engine. Accordingly, a large and deep oil pan under the engine is not required. Therefore, the main mass of the engine may be placed lower in the vehicle. Dry sump lubrication systems are commonly used with high-performance engines, such as racing vehicles.
In vehicles with a dry sump lubrication system, oil is pumped from the external oil tank or reservoir to bearings or other parts of the engine that require lubrication. Oil that is thrown from the crankshaft bearings during operation of the engine drains to the sump located in a lower part of the crank case. Oil received in the sump is pumped back to the oil tank by a scavenge pump. This oil contains a large quantity of entrained air, which is absorbed into the oil due to splashing during the lubricating process. Entrained air lowers the lubricating efficiency of the oil. A deaerator or air separator is sometimes provided in the external oil tank to deaerate the oil so that oil returning from the oil tank to the engine is deaerated.

Dry sump oil tank assembly for a vehicle


A time-division multiplex system is disclosed where the data from two sources is coupled over a multiplexer controller by a generator comprising an XOR gate and a pair of latches where the output of both latches are coupled to the XOR gate and an inverter at the input of each latch. One of the latches is gated by a master clock signal and the other latch is gated by a clocked signal skewed approximately one-half clock cycle.

In computer systems, logic chips and modules (modules may be thermal conduction modules (TCMs) or normal cards) are connected together through wires that rum through a board. In many cases the number of conductors which connect these chips through the module or module to the board are a limiting factor in the design of the computer system. This application presents a method for reducing the number of these connections by approximately half with minimal impact on the design of the system. The method involves sending two signals on each wire connection in a time multiplexed fashion. Previous schemes have been proposed using this technique but have required double frequency clocking schemes or registers, which are very difficult to implement. The system being disclosed herein only requires a skewed clock rather than double-frequency clocks to registers. U.S. Pat. No. 4,926,432 of Zukowski entitled "Time-Division-Multiplexed Data Transmission System" illustrates a time-division-multiplex data transmission system that employs a skewing network to selectively skew each of a plurality of input signals by successively increasing integral multiples of the average period of the multiplex output signal. The skewed signals are merged in a combinatorial merging network having substantially identical delay times and data path to provide a multiplexed signal. In an embodiment shown, the invention provides a time-division-multiplexer in which the incoming signals are precoded prior to being skewed by a skewing network, so that the form of the multiplex output signal is a conventional sequentially interleaved input signal as provided by the prior art multiplexers, and the merging network is a binary tree EXCLUSIVE OR (XOR) gate array. Another multiplexing circuitry is shown in Krol in U.S. Pat. No. 4,010,385 entitled "Multiplexing Circuitry for Time Sharing a Common Conductor". This circuit includes a plurality of passive networks having multiphase clocking signals associated therewith to selectively enable transmission of information signals over a common conductor. No demultiplexing is shown.
U.S. Pat. No. 3,995,120 of Pachynski, Jr., entitled "Digital Time-Division Multiplexing System" describes a multiplexing scheme wherein N parallel digital signals having an average bit rate of frequency F1 are interleaved by a multiplexer to form a single composite line of bit rate F2. Prior to multiplexing signal gaps having a predetermined duration and having a fixed repetition rate are inserted into each of the N parallel signals. Adding gaps to each digital signal permits the bit rate between gaps to be F2/N.
U.S. Pat. No. 4,593,390 of Hildebrand et al. entitled "Pipeline Multiplexer" illustrates a method of multiplexing a selected one of m initial input signals that comprises N stages of select elements.

Time-division-multiplexed data transmission system

International Business Machines Corporation


A dry toner contains fine particles having average sphericity of 0.93 to 0.99, a content of the fine particles having a particle diameter of 2 μm or less in the dry toner is 20% by number or less. A method for manufacturing a dry toner includes a process for dispersing in an aqueous medium containing water and a water-soluble organic solvent, a toner composition contained in an organic solvent by using fine solid dispersing agent; and a process for contracting volume of the dispersed toner composition. Further, the image forming apparatus having a photoconductor; a charger for charging the photoconductor; a light irradiator for irradiating the electrophotographic photoconductor to form a latent electrostatic image; a developer for developing the latent electrostatic image to form a developed image; and a transfer for transferring the developed image to a recording material, and the developer contains the dry toner abovementioned.

1. Field of the Invention
The present invention relates to a toner for use in a developer for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing and the like, and a method for manufacturing the same. More particularly, the present invention relates to a toner for electrophotography utilized in copy machines, laser printers and normal paper facsimiles using the direct or indirect electrophotography developing method, and a method for manufacturing the same. Also, the present invention relates to a toner for electrophotography used in full color copy machines, full color laser printers, full color normal paper facsimiles, and the like using the direct or indirect electrophotographic multi-color image developing method, a method for manufacturing the same, and a method for developing using the toner.
2. Description of the Related Art
Developers used in electrophotography, electrostatic recording, electrostatic printing and the like are developed by a process for developing. For example, a developer is adhered to an image carrier such as a photoconductor upon which an electrostatic image is formed, transferred from the photoconductor to a transferring medium such as a transferring paper by the transferring process and fixed on the paper by the fixing process. As the developer for developing the electrostatic image formed on the surface carrying a latent image, two-component developer comprising a carrier and a toner and one-component developer which does not require a carrier such as magnetic toner and non-magnetic toner are known.
Conventionally, dry toners which are used in electrophotography, electrostatic recording and electrostatic printing are prepared by melt-kneading a toner binder such as styrene resins, polyester and the like along with a colorant, followed by pulverization.
In order to obtain an image with high dignity and high quality, it has been attempted to reduce the particle diameter of toners. However, since the toner particles produced by the conventional admixing or roll-mixing, the pulverization method have indefinite shapes and are mixed with ultrafine particles, and, even though a classification process is applied, it still has a problem not to sufficiently classify toner particles as adhered to the toner with the desired particle diameter, because the ultrafine particles are highly adhesive.
The toner particles having indefinite shapes can also be further pulverized by stirring along with a carrier in a developing unit of an image forming apparatus, or by the contact stress with a developing roller, a toner supplying roller, a layer thickness regulating blade or a friction charging blade, when used as a one-component developing agent, thereby producing ultrafine particles. These ultrafine particles can be adhered or fixed on a carrier or mechanical elements, causing problems. Also, fluidity-imparting agents can be embedded in the toner surface, thereby causing deterioration in the image quality.
Also, the toner particles having indefinite shapes are poor in fluidity as powders and filling capability into a toner container and may need a large amount of a fluidity-imparting agent and impede with the compactness of the toner particles in the toner container. Therefore, the advantage of the small diameter particle cannot effectively utilized. Further, there is a limit in the preparation by the pulverization and thus, it is not possible to provide smaller diameter particles.
In addition, since the process for transferring the image formed by multi-color toner from a photoconductor to a transferring medium or paper in order to form a full color image is complex and the indefinite shape of the pulverized toner particles lead to poor transferring property, image omission may occur and a large amount of toner should be used to compensate such image omission.
Therefore, there are demands for prevention of durability from deterioration of ultrafine particles, production of high quality image without image omission and enhancement of transferring efficiency to lower the running cost by reducing the amount of the used toner. If the transferring efficiency is high, a cleaning unit for removing non-transferred toner from a photoconductor or transferring medium is not needed, the small-size apparatus and low cost can be realized, and waste toner can be reduced. In order to solve these problems caused by the indefinite shape of toner particles, various methods for producing a spherical toner have been researched and suggested.
Methods for producing a toner by suspension polymerization have problems in that only spherical toner particles are produced, apparatuses for removing remaining toner particles on a photoconductor or transferring medium (e.g., cleaning blade or cleaning brush) cannot sufficiently remove the spherical toner particles, causing cleaning failure. Also, due to the spherical shape, the toner surface is exposed, in all directions, to contact with charging members such as a carrier or charging blade, added materials and a charge controlling agent existing in the outer surface can be embedded in the toner surface, and thereby, the fluidity of the toner is deteriorated.
Also, in the methods for producing a toner by suspension polymerization, since the toner particles are subjected under irregular shear during the suspension in an aqueous medium, ultrafine particles may be formed, deteriorate cleaning property and adhere to a carrier or mechanical elements.
Meanwhile, methods for producing a toner by emulsion polymerization have problems in that the thermal post-treatment for shaping is needed to produce spherical toner particles and non-congregated ultrafine particles may remain after cohesion and congregation in aqueous medium, which may cause contamination of the carrier and adhesion to mechanical elements.
In order to solve such problems, Japanese Patent Application Laid-Open (JP-A) No. 07-152202 discloses a method accompanying volume contraction, called as polymer dissolution and suspension method of polymer. In this method, a toner material is dispersed and dissolved in a volatile solvent such as low boiling point organic solvent and emulsified and dropped in an aqueous medium containing a dispersing agent, followed by removing of the volatile solvent. At this point, volume contraction occurs. However, when a solid fine particle-dispersing agent which is not dissolved in the aqueous medium is selected as a dispersing agent, indefinite shaped particles are obtained. Also, when solid contents in the solvent is high in order to productivity, the viscosity of the dispersion phase is increased, whereby the particle diameter is increased and particle distribution is broaden. In contrast, when the viscosity of the dispersion phase is reduced by reducing the molecular weight of a resin, image-fixing properties (particularly, hot offset resistance) was compromised.
Japanese Patent Application Laid-Open (JP-A) No. 11-149179 uses a resin of low molecular weight in the dissolution and suspension method to reduce the viscosity of the dispersion phase and to facilitate emulsification and makes the polymerization occur within the particles to improve the image-fixing properties. However, the improvement of the transferring property or cleaning property is not based on the regulation of the shapes of particles.
Also, since the toner particles are subjected under irregular shear during the suspension in an aqueous medium, ultrafine particles may still be formed, deteriorate cleaning property and adhere to a carrier or mechanical parts.
Further, fixing of this dry toner is performed by heating with a hot roll after developing and transferring. At this point, if the temperature of the hot roll is too high, the toner is excessively melted and adhered to the hot roll (hot offset). If the temperature of the hot roll is too low, the toner is not sufficiently melted, causing fixing failure on the roll. In the term of the energy saving and realization of a small size apparatus, there is needed a toner having a high hot offset temperature (hot offset resistance) and low fixing temperature (low temperature image-fixing properties). Also, the storage stability under heat is needed so that the toner is not blocked at a temperature in the apparatus during storage.
In full color copiers and full color printer, glossiness and color miscibility are demanded. Therefore, toners should have a low melt viscosity and a sharp melting polyester-based toner binder is used. However, since such toners tend to cause hot offset, the hot roll in the conventional full color apparatus is coated with silicone oil. In order to perform coating of the hot roll with silicone oil, an oil tank and oil coating apparatus are needed, whereby the apparatus becomes bigger and more complex. Also, the hot roll may deteriorate and maintenance is periodically needed for operation. Further, oil contaminates copy papers, films for OHP (overhead projector), and particularly, discoloration by oil may occur in OHP.
There has not been suggestions to use a solid fine particle-dispersing agent which critically affects toner formation while focusing on the volume contraction by the solid fine particle-dispersing agent.

Dry toner, method for manufacturing the same, image forming apparatus, and image forming method


A system for determining process parameters for the ladle refinement of steel includes a computer executing a number of software algorithms for determining one or more process parameters for various steel refinement process steps. In one embodiment, for example, the computer is configured to determine the total amount of flux additions to achieve a desired sulfur percentage as part of a steel desulfurization process. In another embodiment, the computer is configured to determine the total quantity of oxygen to be injected into the steel as part of a steel reoxidation process. In still another embodiment, the computer is configured to determine a melting temperature of inclusions within the refined steel, and to determine whether this melting temperature is within an acceptable range to successfully process the steel in a continuous steel strip casting apparatus/process, or whether the steel must be reworked to achieve an acceptable inclusion melting temperature.

It is known to cast metal strip by continuous casting in a twin roll caster. In such a process, molten metal is introduced between a pair of contra-rotated horizontal casting rolls which are cooled so that metal shells solidify on the moving roll surfaces and are brought together at the nip between them to produce a solidified strip product which is delivered downwardly from the nip between the rolls. The molten metal may be introduced into the nip between the two rolls via a tundish and a metal delivery nozzle system located beneath the tundish so as to receive a flow of metal therefrom and to direct it into the nip between the rolls, so forming a casting pool of molten metal supported on the casting surfaces of the rolls immediately above the nip. This casting pool may be confined between side plates or dams held in engagement adjacent the ends of the rolls so as to dam the two ends of the casting pool against outflow, although alternative means such as electromagnetic barriers have also been proposed.
Twin roll casting has been applied with some success to non-ferrous metals which solidify rapidly on cooling, for example aluminum. However, there have been problems in applying the technique to the casting of ferrous metals. One particular problem has been the propensity for ferrous metals to produce solid inclusions which clog the very small metal flow passages required in a twin roll caster.
The use of silicon-manganese in ladle deoxidation of steel was practiced in ingot production in the early days of Bessemer steelmaking. As a result, the equilibrium relations between the reaction product molten manganese silicates and the residual manganese, silicon and oxygen in solution in steel are well known. However in the development of technology for the production of steel strip by slab casting and subsequent cold rolling, silicon/manganese deoxidation has generally been avoided and it has been generally considered necessary to employ aluminum killed steels. In the production of steel strip by slab casting and subsequent hot rolling followed often by cold rolling, silicon/manganese killed steels produce an unacceptably high incidence of stringers and other defects resulting from a concentration of inclusions in a central layer of the strip product.
In the continuous casting of steel strip in a twin roll caster, it is critically important to generate a finely controlled flow of steel at constant velocity along the length of the casting rolls to achieve sufficiently rapid and even cooling of steel over the casting surfaces of the rolls. This requires that the molten steel be constrained to flow through very small flow passages in refractory materials in the metal delivery system under conditions in which there is a tendency for solid inclusions to separate out and clog those small flow passages.
After an extensive program of strip casting various grades of steel in a continuous strip roll caster, it has been determined that conventional aluminum killed carbon steels or partially killed steel with an aluminum residual content of 0.01%, or greater, generally cannot be cast satisfactorily because solid inclusions agglomerate and clog the fine flow passages in the metal delivery system to form defects and discontinuities in the resulting strip product. This problem can be addressed by calcium treatment of the steel to reduce the solid inclusions, but this is expensive and needs fine control adding to the complexity of the process and equipment. On the other hand, it has been found that it is possible to cast strip product without stringers and other defects normally associated with silicon/manganese killed steels because the rapid solidification achieved in a twin roll caster avoids the generation of large inclusions and the twin roll casting process results in the inclusions being evenly distributed throughout the strip rather than being concentrated in a central layer. Moreover, in thin strip casting, it is possible to adjust the silicon and manganese contents so as to produce liquid deoxidation products at the casting temperature to minimize agglomeration and clogging problems.
In conventional silicon/manganese deoxidation processes, it has not been possible to lower free oxygen levels in the molten steel to the same extent as is achievable with aluminum deoxidation, and this problem in turn has inhibited desulfurization. For continuous strip casting, it is desirable to have a sulfur content of the order of 0.009% or lower. In conventional silicon/manganese deoxidation processes in the ladle, the desulfurization reaction is very slow, generally more than an hour, and it becomes impractical to achieve desulfurization to such low levels particularly in the case where the steel is produced by the EAF route using commercial quality scrap. Such scrap may typically have a sulfur content in the range 0.025% to 0.045% by weight. Details relating to strategies for enabling effective and efficient deoxidation and desulfurization of silicon/manganese killed steel, and for refining of high sulfur silicon/manganese killed steel to produce low sulfur steel which has free oxygen levels suitable for continuous thin strip casting, are disclosed in co-pending U.S. Patent Application Ser. No. 60/280,916, which is assigned to the assignee of the present invention, and the disclosure of which is expressly incorporated herein by reference.
When casting thin steel strip in a twin roll caster the molten steel in the casting pool will generally be at a temperature of the order of 1500° C. and above, and it is therefore necessary to achieve very high cooling rates over the casting surfaces of the rolls. It is particularly important to achieve high heat transfer and extensive nucleation on initial solidification of the steel on the casting surfaces to form the metal shells. U.S. Pat. No. 5,720,336 describes how the heat flux on initial solidification can be increased by adjusting the steel melt chemistry such that a substantial proportion of the metal oxides formed as deoxidation products are liquid at the initial solidification temperature so as to form a substantially liquid layer at the interface between the molten metal and each casting surface. It has been determined that nucleation is also dependent on the presence of oxide inclusions in the steel melt and that surprisingly it is not advantageous in twin roll strip casting to cast with "clean" steel in which the number of inclusions formed during deoxidation has been minimized.
Steel for continuous casting is subjected to deoxidation treatment in the ladle prior to casting as described hereinabove. In twin roll casting the steel is generally subjected to silicon manganese ladle deoxidation although it is possible to use aluminum deoxidation with calcium addition to control the formation of solid Al2O3 inclusions that can clog the fine metal flow passages in the metal delivery system through which molten metal is delivered to the casting pool. It has been determined that while lowering the steel oxygen level of unrefined molten steel allows for subsequent desulfurization thereof as described hereinabove, it undesirably reduces the volume of oxide inclusions. If the total oxygen content of the steel is reduced below a certain level, the nature of the initial contact between the steel and roll surfaces can be adversely effected to the extent that there is insufficient nucleation to generate rapid initial solidification and high heat flux. Following desulfurization, free oxygen is therefore injected into the molten steel to raise its free oxygen content to a level that promotes sufficient nucleation to generate rapid initial solidification of the molten steel onto the casting rolls and production of a satisfactory strip-product. As a result of the reoxidation of the molten steel, it then contains a distribution of oxide inclusions (typically MnO, CaO, SiO2 and/or Al2O3) sufficient to provide an adequate density of nucleation sites on the roll surfaces for initial solidification and the resulting strip product exhibits a characteristic distribution of solidified inclusions. Details relating to one strategy for injecting oxygen into a ladle of steel prior to casting thereof are set forth in co-pending U.S. Patent Application Ser. No. 60/322,261, which is assigned to the assignee of the present invention, and the disclosure of which is incorporated herein by reference.
While the above-referenced patent applications disclose systems and strategies for carrying out deoxidation, desulfurization and reoxidation steps in the ladle refinement of steel prior to casting into steel strips, these processes tend to require tedious techniques for determining the process parameters required to achieve the refined steel. For example, to reduce the percentage of sulfur in the molten steel to a desired percentage, a controllable quantity of flux must be added thereto. As another example, the melting point of inclusions in the reined molten steel must be below a threshold temperature to ensure that a substantially liquid oxide layer exists at the interface between the molten metal and each casting roll surface. The total amount of free oxygen added in the reoxidation step, as well as the amount and composition of flux and/or alloy additions, must therefore be known and controlled to provide for a desired inclusion melting temperature in the batch or ladle of refined steel. Finally, it is necessary from a castability standpoint to determine the inclusion melting temperature of the batch of refined steel to determine whether the ladle may be routed to the strip casting process or whether it requires re-working in order to adjust the inclusion melting temperature. What is therefore needed is a strategy for determining these various process parameters for the ladle refinement of steel, wherein such strategy is straightforward in its application, easily implemented in software, and readily adaptable to a continuous steel strip casting process.

Model-based system for determining process parameters for the ladle refinement of steel


In the present invention, an EL element section (1) includes a plurality of arranged cells, each including a thin film EL element formed so as to emit white light, and a like number of predetermined-color filters (2) formed on the surface of the EL element section and corresponding to the cells such that each cell is caused to emit light in accordance with image information and the emitted light is output through the corresponding color filter to color display purposes. Thus, a very thin color display apparatus is provided in which contrast is good and the dependency of the luminance on the visual sensation is also good. The thin film EL element according to the present invention uses a luminous layer of zinc sulphide containing nitrogen, so that transitional luminescence occurs among a plurality of levels, and hence rays of light having various wavelengths are emitted to thereby provide white light containing three primary colors.

In a field of color display apparatus, there is an increasing tendency for small thin low-power consuming ones to be demanded, and pocket-size television sets using liquid crystal as a shutter have come as goods to public notice.
As shown in FIG. 18, a thin full-color display apparatus used in a conventional pocket-size television set includes shutter means 100 in the form of a matrix of liquid crystal cells C, a light source 101 disposed behind the shutter means, and filter means 102 disposed before the shutter means and including a repeat of a red transparent filter R, a green transparent filter G and blue transparent filter B arranged in order in correspondence to the liquid crystal cells. By controlling voltages applied to the respective liquid crystal cells in accordance with image information, quantities of light from the light source and passing through the liquid crystal cells are adjusted to thereby adjust the luminance and chromaticity of the respective pixels.
However, in such thin full-color display apparatus, there is the problem that contrast is not excellent due to the characteristic of the liquid crystal itself and that the angle of visual field is very narrow. In such apparatus, a light source as backlight is needed, so that there is the problem that the entire apparatus would be thick although the liquid crystal section itself is thin.
The thin-film EL elements each include a thin transparent luminous layer and has no granularity. Therefore, external incident light and light emitted within the luminous layer are not scattered, so that they cause no halation or oozing, the display is clear and provides high contrast. Therefore, they are highlighted as being used for a display or illumination unit.
The basic structure of a thin-film EL element includes a double dielectric structure which in turn includes on a transparent substrate a transparent electrode of tin oxide (SnO.sub.2) layer, etc., a first dielectric layer of tantalum pentaoxide layer, etc., a thin luminous layer of zinc sulfide (ZnS), etc., and containing manganese (Mn), etc., a second dielectric layer of tantalum pentaoxide, etc., and a rear electrode of an aluminum (Al) layer, etc., laminated in order.
The process of luminescence is as follows. If a voltage is applied across the transparent electrode and rear electrode, the electrons trapped at the interface level are pulled out and accelerated by an electric field induced within the luminous layer so that they have energy enough to strike orbital electrons in Mn (the luminescent center) to thereby excite same.
When the excited luminescent center returns to its ground state, it emits light.
Researches in which a multicolor display panel is fabricated using thin-film EL elements have recently become popular and various researches have been made on making full color panels.
A thin-film EL element emitting white light uses a luminous layer of zinc sulfide containing praseodymium fluoride (PrF.sub.3), as disclosed in Yoshihiro Hamakawa et al., The Institute of Electronics and Communication Engineers of Japan Technical Research Report, CPM 82-10, 1982.
As shown in FIG. 19, the thin-film EL element using the luminous layer of zinc sulfide containing praseodymium fluoride has peaks at about 500 and 650 nm in the emission spectrum. The rays of light at 500 and 650 nm are in complementary-color relationship to each other and show as if they were white light. However, the light does not contain three primary colors, so that it cannot be used for full color display.
A thin-film EL element having such structure is all transparent except for its rear electrode. Thus external incident light is reflected by the rear electrode and the reflection interferes with the light from the luminous layer so that it does not provide a satisfactory contrast ratio and thus only display devices having low display quality would be provided.
The present invention has been made in view of such situations. It is an object of the present invention to provide a thin color display apparatus which provides high contrast and a wide angle of visual field.
It is another object of the present invention to give high dielectric strength to the thin-film EL elements of a color display apparatus.
It is a further object of the present invention to improve the contrast of the thin-film EL elements.


A molded transformer includes a transformer body including a coil bobbin having a spool having a central through-hole and a collar at each of two ends thereof, and a conductive wire, such as a copper wire, wound around the spool, and an EE type or EI type ferrite core which is inserted into the coil bobbin; and a thermoplastic resin for molding the transformer body in such a manner that only a terminal portion used for mounting is exposed through the resin. The resin has a low molecular weight, ensuring a low molding stress and a low melting viscosity.

1. Field of the Invention
The present invention relates to a molded transformer which is used in various types of video apparatus, household electric appliances, acoustic apparatus, industrial apparatus or communication apparatus.
2. Description of the Related Art
A conventional transformer will be described below.
FIG. 11 shows the internal structure of a conventional transformer. A spool 1 has a central through-hole 2. The spool 1 also has a collar 8 at each of the two ends thereof, and a lower collar 4 at the lower end of each of the collars 8. Maker terminals 5 for wiring and user terminals 6 used by the user are formed integrally with the spool 1. A conductive wire 3, such as a copper wire, is wound around the spool 1 and is connected to the maker terminals 5 to form a coil bobbin. An EE type or EI type ferrite core 7 inserted into the coil bobbin 1 is fixed to the coil bobbin 1 by coating an adhesive 14, such as an epoxy resin, on the joining surface of the ferrite core 7 and then by heat setting the adhesive 14 at a temperature ranging from 100.degree. C. to 200.degree. C. to form a transformer body in which a closed magnetic path is formed. The thus-arranged transformer body is inserted into a casing 9 made of a plastic resin, a highly insulated resin 10, which may be silicon resin, is injected into the casing 9, and then the casing 9 is sealed by a bottom plate 11, which may be made of a plastic resin, in such a manner that the user terminals 6 are exposed through the resin to form a transformer.
FIG. 12 shows a shielded type transformer in which a box-shaped shielding casing 12 covers the transformer arranged in the manner described above from above.
In the aforementioned conventional transformer, the number of parts is large, and the production process is complicated. The plant and equipment investment required for automating the wire winding process and the core assembly process, which are necessary for the function of the transformer, increases the amount which has to be invested but this investment has a beneficial effect. The plant and equipment investment required for automating the subsequent processes, such as the casing insertion process, the silicon injection process and the bottom plate insertion process, which are necessary for the additional functions, increases the amount which has to be invested too much.
Furthermore, since the conventional transformer is manufactured by combining and fitting the bare transformer body, the casing and the bottom plate, the shape of the transformer and the dimensions of the user terminals are very unstable. This deteriorates the yield of the transformer automatic mounting process performed by the user.
A reduction in the number of parts and an improvement in the shape of the transformer and in the dimensional accuracy of the user terminals may be achieved by plastic molding the entire transformer. Generally, plastic molding employs thermosetting resins, such as an epoxy resin. The thermosetting resins require a long molding time, and generate burrs during molding. Therefore, a burr removing process must be conducted after molding, and the productivity of the molding process is thus low.
In the conventional transformer, when a transmission noise, which is an externally radiant noise induced in the transformer and transmitted to the circuit, is generated or when a malfunction of the circuit occurs due to leaking magnetic flux generated from the transformer, the transformer body is covered with the box-shaped shielding casing 12 to suppress, the influence of the noise. However, this increases assembly manhours. Also, when the user desires to mount the parts with a high density, insulation between the adjoining parts must be provided. Therefore, the transformer mounting position is limited, thus limiting the high-density mounting of the parts.
Furthermore, since the joining surface of the EE type or EI type ferrite core 7 is fixed using the adhesive 14 in the core assembly process, the adhesive 14 coating and setting processes are required, making the production process complicated. Also, since an epoxy type thermosetting adhesive having a high mechanical strength and a high heat resistance is generally employed to adhere the ferrite core 7, setting of the adhesive 14 requires a setting tank of a temperature ranging from 100 to 200.degree. C., thus increasing the amount which has to be invested in plant and equipment.

Matsushita Electric Industrial Co., Ltd.


A method and system to evaluate the maintenance costs of products, having learning and application phases. Each phase is divided into two steps. The first analyzes product characteristics. The second is based on maintenance agreement conditions. During the first step of the learning phase, a first maintenance cost is estimated over the domain of a first variable representing product characteristics. Correction coefficients, based on other product characteristics, may be estimated to improve the first maintenance cost estimation. During the second step new correction coefficients are estimated according to maintenance agreement conditions. During the application phase, a first maintenance cost estimation is done according to the modality of the first variable, and adjusted depending on other product characteristics and maintenance agreement conditions.

Generally, products such as automobiles have been financed through a personal loan system, whereby the purchaser makes a down payment, takes title to the product and pays the loan balance in monthly payments which amortize the full amount of the loan. More recently, leasing arrangements have been introduced whereby the lessee makes monthly rental payments, returning the product to the lessor at the end of a predetermined term specified in the lease. Title to the product remains in the lessor. It is sometime specified in the lease that the lessee may at his option purchase the product for a stated value when the lease expires. The conditions of the lease may also include charges, e.g. a charge for abnormal mileage or wear and tear for lease of an automobile.
U.S. Pat. No. 4,736,294 discloses data processing methods and apparatus for managing vehicle financing. The data processing system provides information to assist in granting a loan, and determining at the time of making the loan a residual value of the vehicle at a predetermined option date.
Considering vehicle leases, at the signing of the lease, the lessee chooses a vehicle and states how many years he intends to keep it and the approximate mileage he intends to cover. Generally speaking, the lease duration is normally between 1 to 4 years while the number of miles varies from 20,000 to 60,000. Depending upon the vehicle and lease duration and mileage, the lessor determines monthly rental payments at the time of making the lease by estimating the resale value factor at the end of the lease, also referred to as the residual value factor, and costs due to the benefit margin, insurance and maintenance. Without taking into account the margin of the lessor, insurance, maintenance, etc., for sake of clarity, the sum of monthly rental payments corresponds to the difference between the sticker price, i.e. the purchasing price of the automobile as proposed by the manufacturer, and the resale price. If the resale price at the end of the lease is less than the estimation done at the time of making the lease, monthly rental payments have been underestimated and, as a consequence, the lessor loses money. Reciprocally, if the resale price at the end of the lease is more than the estimation done at the time of making the lease, monthly rental payments are overestimated, and thus the leases are not attractive. During the lease, the lessee may modify it to adapt its duration or mileage if the lessor agrees. In such a case, the residual value has to be reevaluated to adjust monthly rental payments accordingly.
In parallel with product loan, rental or purchase, maintenance agreements are often proposed. Such contracts are particularly suitable for leases since they reduce the lessee's care and provide a known and constant quality of service that increase residual value factor estimation accuracy. Thus, by adjusting the product value at the end of the lease, the lessor can purpose attractive leases without increasing commercial risks. By making a regular payment, e.g. a monthly payment, the lessee can effectively budget for the servicing and repair of the leased product since the lessor takes preventive and repair maintenance to his charge, e.g. overhauling of motor cars as advised by manufacturers.
Maintenance costs depend both on the product characteristics and maintenance agreement conditions, e.g. lease duration and mileage for vehicle leases. However, due to the general complexity of the products that are subjects of the maintenance agreements and the duration of the maintenance agreement, e.g. several years, the maintenance costs are difficult to model, and thus are generally evaluated approximately and experimentally by specialists.

This patent is subject to a terminal disclaimer.

System and method for evaluating maintenance costs of products

International Business Machines Corporation


There is provided a semiconductor device capable of supplying an analog input signal higher than or equal to an operating power supply voltage. An electrostatic discharge protection circuit corresponding to the analog input signal is provided for an external terminal that is supplied with an analog input signal generated with a first power supply voltage. A voltage divider resistor divides the analog input signal passing through the electrostatic discharge protection circuit into a voltage corresponding to a second power supply voltage lower that the first power supply voltage. An input circuit operating on the second power supply voltage receives the analog input signal divided by the voltage divider resistor to form an internal analog signal. There are provided first and second unidirectional elements. The first unidirectional element passes current from the input circuit's input terminal to the second power supply voltage. The second unidirectional element passes current from a circuit ground potential to a first circuit's input terminal.

The present invention relates to a semiconductor device. More specifically, the invention relates to a technology effectively applicable to a DVD signal processing-oriented semiconductor integrated circuit provided with an optical pickup interface for DVD (digital video disk).
According to the example described in Japanese Unexamined Patent Publication No. Hei 5(1993)-327460, the resistor provided to the input protection circuit is used for voltage conversion by dividing different voltage signal levels in semiconductor integrated circuits such as LSI having different operating voltages. Japanese Unexamined Patent Publication No. Hei 10(1998)-145219 discloses the semiconductor input circuit that performs capacity division and coupling to divide and input a voltage amplitude of a logic signal supplied from the outside.
Patent document 1: Japanese Unexamined Patent Publication No. Hei 5(1993)-327460
Patent document 2: Japanese Unexamined Patent Publication No. Hei 10(1998)-145219


A digital loop filter installed in an all-digital phase-locked loop (PLL) receives a digitally controlled oscillator (DCO) control code transmitted from a PLL controller in the all-digital PLL, and calculate an average value, such that the PLL controller can produce another DCO control code by the average value for controlling and adjusting an output signal of a digitally controlled oscillator (DCO) in the neighborhood of the average value to maintain compensating a phase/frequency difference with an input signal, so as to minimize the jitter effect of the input signal on the all-digital PLL, reduce the jitter effect of the output signal, and keep tracking and locking the frequency and the phase of the input signal.

1. Field of Invention
The present invention relates to a digital loop filter installed in an all-digital phase-locked loop (PLL) for reducing the jitter effect of an input signal to the all-digital PLL as well as reducing the jitter effect of the output signal, such that the all-digital PLL can keep tracking and locking the frequency and phase of the input signal.
2. Description of Related Art
As the consumption and importance of communication products increase and integrated circuits develop rapidly, the demand for communication integrated circuits increases correspondingly, wherein a phase-locked loop (PLL) is one of the common circuits applied for the modulation and demodulation in the communication field and used as a frequency synthesizer on a radio system or a clock signal recovery system with digital circuits.
The principle of the PLL is to track and lock the phase and the frequency of the input signal and the output signal, such that the two signals can be maintained consistently all the time. If the phase error of two signals is equal to zero or very small, then we generally call it is locked. Note that fast lock-in time becomes increasingly important and a necessary feature for the PLL design.
The conventional design of a digital loop filter generally uses an accumulator to average and eliminate the jitter effect of the input signal to the PLL as disclosed in issued patents such as U.S. Pat. No. 7,042,972 issued to Qualcomm, U.S. Pat. No. 7,145,399 issued to Texas Instruments, and a journal entitled "Phase Domain All-Digital Phase-Locked Loop" published in the IEEE Transactions on circuits and systems II on March 2005.
However, the foregoing issued patents and journal adopt the accumulation method to eliminate the jitter effect of an input signal to the PLL, but the accumulator will also record jitter information even when the jitter of the input signal is very large. As a result, the output of the accumulator will become unstable, and the period jitter of the output signal of the PLL cannot be reduced, and thus causing problems to the design of digital loop filters.
In addition, U.S. Pat. No. 5,473,285 entitled "Method and apparatus for performing phase acquisition in an all digital phase lock loop" and issued to Motorola discloses a method of updating an anchor register, and capable of generating a baseline frequency required by the PLL controller. Four consecutive control signals (UP/DOWN) are used for updating the baseline frequency, so as to reduce some of the jitter effect of the input signal on the PLL. However, if the jitter of the input signal is very large, the method of updating an anchor register cannot suppress the jitter effect of the input signal on the PLL effectively, and thus the method cannot reduce the jitter effect of the output signal to the PLL, and the issue of period jitters still exists.

Digital loop filter for all-digital phase-locked loop design


A thermal printer is disclosed which is a adapted to form an image on a thermal print medium of a type in which a donor element transfers dye to a receiver element upon receipt of a sufficient amount of thermal energy. The printer includes a plurality of diode lasers which can be individually modulated to supply energy to selected dots on the medium in accordance with an information signal. The print head of the printer includes a fiber optic array having a plurality of optical fibers coupled to the diode lasers. The thermal print medium is supported on a rotatable drum, and the fiber optic array is movable relative to the drum. In order to prevent banding in an image produced on the print medium, the two outside fibers in the array are used for preheating and postheating of inner scan lines. The printer is particularly well adapted for use as a proof printer for half-tone reproductions of images. The printer suppresses any visual artifacts that are resultant from interactions of selected patterns of half-tone dots and incremental dots which are used by the printer to generate an image. The printer does not however mask any artifacts that are resultant from interaction of image components (such as picket fences) with a selected pattern of half-tone dots.

When graphical information, such as photographs or artwork, is printed in a typical publication, a half-tone printing process is used. Half-tone printing is capable of producing a very high fidelity reproduction of a photograph or artwork if various printing parameters are chosen correctly. However, the half-tone printing process can also introduce some undesirable image distortions when printing parameters are incorrectly chosen. For example, some repetitive patterns in an image (such as a picket fence) may beat against a particular pattern of dots selected for the half-tone process. This causes objectionable repetitive variations in image density which are known as moire patterns or fringes.
In the publication field, the selection of photographs and artwork for a publication has heretofore been done by people who are indirectly involved with the process of half-tone printing. Typically, the selected images are sent to a printer so that a proof sheet can be generated. A proof sheet is made on a press which generates a half-tone reproduction of the selected images. The proof sheets, in half-tone format, are returned to the image selectors. The image selectors then determine whether or not their initially selected images are indeed suitable for the desired publication.
If the images are not suitable, another round of proof sheets may be generated using different images or different half-tone printing parameters. This iterative process can be very costly and time consuming. In order to reduce the costs of generating half-tone proofs, various forms of proof presses have been devised and used. Typically, a proof press is smaller and less costly to operate than a full sized printing press. A proof press is designed so that half-tone printing can be performed in a cost-effective manner for a small number of proof sheets.
However, in spite of the improved cost effectiveness of using a proof press, there remain some substantial problems in getting images selected and ready for inclusion in a publication. For, example, a proof press is a complex and expensive piece of equipment. Consequently, proof presses are typically found only in print shops. Thus a person selecting images is still required to go through the cumbersome process of obtaining proof sheets from a source that is remote or disconnected from his or her office. Additionally, presently available proof presses do not make an exact duplicate of the half-tone reproduction which will be generated by the final press. At best a simulation is made.
A more ideal proof press would be simple to use and inexpensive enough to be placed in the offices of the selectors of images. It would also be capable of producing high fidelity predictions of the appearance of a final output of a half-tone printing press.
Thermal printers are simple to use and have the capability of producing high fidelity images. However, thermal printers have heretofore been impractical for the production of large images that are required as proof sheets. Typically, the desired proof sheets are 22 inches by 17 inches.
In one type of thermal printer, a dye-donor element is placed over a dye-receiving element, and the superposed elements are supported for cooperation with a print head having a plurality of individual heating resistors. When a particular heating resistor is energized, it causes dye from the donor to transfer to the receiver. The density or darkness of the printed color dye is a function of the energy delivered from the heating element to the donor. One of the problems in printers of this type is that the thermal time constant of the resistors is quite long. As a result, the printing speed is relatively slow, and the image contrast is limited.
It is known to use lasers instead of the resistors to provide the thermal energy in thermal dye transfer printing. In U.S. Pat. No. 4,804,975, for example, there is shown thermal dye transfer apparatus which comprises an array of diode lasers which can be selectively actuated to direct radiation onto a dye-carrying donor. Radiation from the diode lasers is modulated in accordance with an information signal to form an image on a thermal print medium. The diode laser array extends the full width of the print medium. One problem with this apparatus is that it is too expensive for many applications. The initial cost of such a large array is relatively high, and failure of only one diode laser in the array will result in a discarding of the entire array. A further problem with the patented apparatus is that it is difficult to vary the half-tone dot pattern of the reproduced image.
It is desirable therefore to provide a proof printer which effectively illustrates image artifacts that are a function of interactions of the image a selected pattern of half-tone dots. It is particularly desirable to provide a proof printer that is sufficiently simple to be employed in a typical office setting.

Thermal printer capable of using dummy lines to prevent banding


The present invention relates to a method for the authentication of dosage forms such as tablets, in particular pharmaceutical tablets, by reading, i.e. detecting, code structure from the tablet, reading additional information from the package or on an information sheet, and then comparing the readings to verify authenticity. The code structure may be randomized on a plurality of tablets disposed in identifiable locations in a shared package such that the detected code structures define a unique digital signature for the package of tablets.

Pharmaceuticals and cosmetics are high technology products which require very specialized material systems and production procedures as well as very large investments in development and marketing. Because of public safety concerns, authorities place very stringent requirements on the verification and authenticity of such products. Companies therefore have to make huge investments in the tracking and tracing of these products to ensure authenticity. In addition, as these products usually have large sales margins and are distributed globally, it is not surprising that cosmetics manufacturers and pharmaceutical companies suffer from enormous losses due to counterfeiting. The problem has been aggravated by strongly increased sales over the internet, where everything from counterfeit Viagra to false glucose tests is readily available.
Track-and-trace features in the pharmaceutical market have been applied to packages. For example, holograms, optically variable inks, fluorescent dyes, and other identification features are attached to the packages, e.g., by adhesive tags. Alternatively, such labels are laminated to the carton or are directly applied to the packages. The main drawback of such labels is that they are not an integral part of the tablet and therefore do not provide 100% security. For example, if the authentic product is separated from the package, the package can be refilled with a false product. Therefore, direct verification of an authentic tablet, and ensuring that the authentic tablet is in the correct package, remains a primary concern.
Although there are some known approaches for secure labelling of the tablets themselves, each suffers from one or more drawbacks.
For instance, techniques based on forgery-resistant signatures, such as DNA of known sequence (U.S. Pat. No. 5,451,505) or molecules with characteristic isotopic composition or micro-particles with characteristic colour layer sequence (U.S. Pat. No. 6,455,157 B1), are considered unsuitable for pharmaceutical tablets, as these signatures are administered simultaneously and require additional regulatory approval.
WO2006/027688A1 describes an article, such as a tablet, having a visible diffractive microstructure on its surface or at an interface. Illuminated with white light, the tablet shows a rainbow colour effect similar to holograms. The diffractive microstructure can provide an indication of authenticity of the tablet. Although suitable for verification purposes, that document discloses a security element that is visible to the unaided eye. This visibility can tip off counterfeiters. Second, it is difficult to encode a large amount of data in such diffractive microstructures, and to do so consistently.
EP1958620A1 teaches a verification method based on three-dimensional structures such as barcodes or logos impressed or embossed in tablets, in particularly pharmaceutical tablets. Further methods to manufacture tablet compression tools are disclosed. This patent application is incorporated in its entirety.
A number of optical detection devices useful for analysing three-dimensional structures are known. White light interferometers are state of the art but operate rather slowly. Optical coherence tomography (OCT) is another known technique capable of visualising three dimensional patterns, even if they are located at an interface below the surface of an article. The depth that can be visualised in a material depends on the optical properties of the material. It can be up to a few millimeters at present. U.S. Pat. No. 6,469,489 describes an array sensor which is used for parallel optical low-coherence tomography (pOCT) which enables real-time 3D imaging for topographic pattern. It provides fast, three-dimensional and structural information with spatial resolution in the micrometer range. A plurality of electrical detection circuits with parallel outputs can form a one-dimensional or two-dimensional array sensor for the coherent or heterodyne analogue detection of intensity modulated optical signals simultaneously for all pixels with a high dynamic range. The array sensor may be used, e.g., for optical 3D measurements, and especially in optical low-coherence tomography. It is known to use OCT for investigating the human skin, to control the quality of fast production processes (e.g., in die-bonding), in SMD pick-and-place systems, as well as in mechanical inspection systems. Variants of these detection techniques do not use interferometry, but time-modulated optical signals to provide accurate 3D measurements of objects. Such variants often use parallel processing of lock-in signals on a single chip to provide fast and accurate distance information to an object. One example is time-of-flight (TOF) or related methods, where infrared or visible light from a camera's internal lighting source is time modulated and reflected by objects in the scene. It travels back to the camera, where its time of arrival is measured independently by each pixel on a sensor array or chip. In contrast to conventional cameras, such cameras provide a complete distance map of all objects in the field of view on a pixel-by-pixel basis.

Method for the authentication of dosage forms