In embodiments, an evolved Node B (eNB) of a wireless communication network may map individual enhanced control channel elements (eCCEs) of a physical resource block (PRB) pair to a plurality of non-continuous enhanced resource element groups (eREGs) of the PRB pair. The eNB may further map the plurality of eREGs to individual antenna ports for transmission to the UE, with individual antenna ports associated with a continuous group of eREGs. The eNB may assign at least a portion of an enhanced physical downlink control channel (ePDCCH) to one or more of the eCCEs for transmission to the UE. Additionally, or alternatively, an eNB may map eCCEs of a plurality of PRB pairs to a plurality of distributed resource block (DRB) pairs.

In wireless communication networks, an evolved Node B (eNB) transmits a control channel, such as an enhanced physical downlink control channel (ePDCCH) to a user equipment. The ePDCCH includes downlink control information (DCI) with information used by the UE to receive a physical downlink shared channel (PDSCH). In many wireless communication networks, the eNB may use either localized or distributed transmission of the ePDCCH. However, distributed transmission of the ePDCCH may present a different interference fingerprint than localized transmission of the ePDCCH, which may make it difficult for a neighboring cell to cancel the interference.
Additionally, in some wireless communication networks, it is not permitted for the PDSCH to be transmitted in the same physical resource block (PRB) pair as the ePDCCH. This may cause bandwidth wastage due to unused resource elements of the PRB pair that is used to transmit portions or all of the ePDCCH.

Mapping of enhanced physical downlink control channels in a wireless communication network


Technologies are generally described for reducing the from-power-grid energy consumption of a wireless network such as a cellular network over a period of time through cell size adaptations. According to some examples, cell sizes for the base stations may be optimized by decomposing the cell size optimization into two approaches: a multi-stage energy allocation approach and an energy consumption minimization approach. By implementing an energy allocation policy based on available energy type (e.g., from-power-grid or renewable) and an approximation technique for the energy consumption minimization, cell size optimization for each base station may be achieved resulting in network-wide enhancement of renewable energy usage vs. from-power-grid energy usage.

Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
In wireless cellular networks, energy consumption is mainly drawn from base stations (BSs). According to the power consumption breakdown, BSs may consume more than half of the power of a cellular network. As the number of BSs increases along with expanded coverage and networks of competing service providers, reducing the power consumption of BSs may be a desirable goal for small carbon footprint cellular networks. Designing energy efficient base stations to reduce the energy consumption of cellular networks is one approach pursued by service providers.
Efforts on making cellular networks more "green" (i.e., environmentally friendly through increased use of renewable energy and reduced use of fossil-based energy) may further include designing power saving communication protocols that adjust the transmit power of the transceivers according to the traffic intensity as an approach. A further approach may include designing heterogeneous radio access networks which may utilize a diverse set of base stations to improve spectral and energy efficiency per unit area. Yet another approach may include designing off-grid BSs and communication protocols to enable utilization of renewable energy in cellular access networks. Renewable energy such as sustainable biofuels, solar, and wind energy are promising options for reducing the from-power-grid energy consumed by BSs and reducing the carbon footprint of cellular networks.

Cell size optimization for energy savings in cellular networks with hybrid energy supplies


A machine for cutting and crimping the ends of a helical coil inserted into holes at an edge of a book to hold the coil in place is adjustable to accommodate different diameters of coil. A guide member for centering the axis of the coil in a centering direction is adjustable to accommodate different diameter coils and for adjusting the location of the axis in an adjustment direction at right angles to the centering direction depending upon the diameter of the coil. A cutting device has a blade movable in a slot of an anvil to shear on one side and to bend on the other side to form a crimped end portion. The adjustment of the axis causes the cutting device to cut the end portion longer for larger coils. The cutting device is adjustable to rotate the anvil relative to the axis to accommodate different helix angles.

In U.S. Pat. No. 6,000,897 of Desjarlais issued Dec. 14, 1999 is disclosed a machine for inserting a plastic coil into aligned holes at the edge of a book for binding of the book. Such coils are formed of a plastic filament which is wound into a helical coil. Coils of different diameters can be selected for different thicknesses of book with the diameters commonly available lying in the range 6 mm to 30( ) mm.
Also in U.S. patent application Ser. No. 10/449,713, filed Jun. 2, 2003 now issued as U.S. patent INSERT and corresponding Canadian application, filed May 27, 2003, Ser. No. 2,429,874 both entitled BOOKBINDING COIL INSERTION MACHINE is disclosed an improved arrangement for the same purpose.
Both of these patents provide an arrangement for inserting the coil into the book which includes end cutters for cutting and crimping the ends of the inserted coil so that the coil is cut to length and simultaneously the cut end is bent at an angle to the length of the filament forming the coil so that the coil is held in place in the end holes of the edge of the book. The machine disclosed is automated and is thus generally more suitable for longer production runs where the cost of the machine can be justified.
In other lower cost situations such as in smaller offices or in low production runs it is common to use either manual insertion of the coil or to use a roller or belt drive system to assist in coil insertion where the operator holds the book in place at the drive system till the frictional contact between the coil and the drive moves the coil to the required location. Such devices do not include a cutting and crimping device since the complexity is not suitable for the low cost drive system.
In order to effect the cutting and crimping action, therefore, the operator can use a manual cutting tool in the form of a pair of specially designed pliers. However these are awkward to use and sometimes ineffective if not properly located and operated relative to the coil and are disliked by the operators.
Previous devices have been provided for receiving the book and coil and for cutting and crimping the ends of the inserted coil. The operator holds the book in place and the device has a cutter device which is driven by suitable motive force such as pneumatics to effect the cutting action.
One machine of this type is manufactured by Renz of Heuback Germany which is known as "Coil Cut". This device is shown in an operating manual and comprises a pair of cutting devices at spaced positions across the machine for engaging the respective ends. Two V-shaped guides are located just inboard of the cutting devices such that the outside cylindrical surface of the coil is placed to sit in the V. These act to center the coil relative to the cutting device. Also, the height of the V-shaped guide relative to the cutting device is adjustable to accommodate different diameter of coil so as place the position of the filament to be cut in the knife at a required location. It will be appreciated that larger diameter coils require a longer crimped portion relative to smaller diameter coils to prevent the coil from being pulled through the first hole in the book and moving from its required position. This change in length of the crimping action can be obtained by moving the position of the filament relative to the knife so that the cutting action takes place at a different location on the cutting device. The cutting device is then shaped so that the different location on the cutting device causes the length of the crimped portion to be automatically cut to the require length.
The Renz machine is limited in coil size to the range 6 to 20 mm as clearly stated in the Manual. It cannot therefore operate with coils in the range 20 to 50 mm which are commonly available and thus suffers from this clear and severe restriction.
Also the guidance of the coils in the V-shaped guide is of limited effectiveness requiring careful attention by the operator to ensure that the coil is in the required location.
Another machine of this type which is currently available is that manufactured by Marion Inc of Boise Id. This is shown in an Operator's Manual and uses a similar arrangement to that described above. In this arrangement the side of the book is placed on a support plate the height of which is adjustable relative to the position of the cutting device so as to locate the position of the coil in the cutting device.
This machine is operable with coils of diameters 6 to 50 mm but only by purchasing and inserting three replacement cutting devices for different parts of the range. Thus there are three cutting devices where a first operates in the range 6 to 7 mm, a second in the range 8 to 25 mm and a third in the range 12 to 50 mm. These three devices are expensive and complex to replace and set up. Also the placement of the book against a plate does not itself accurately locate the coil leaving possibility for faulty crimping action due to the misplacement of the coil. Hold down devices are proposed to be added for the small size coil since misplacement is more problematic at the small diameters.

Bookbinding coil end cutting and crimping machine


For charging a bootstrap capacitor in a voltage converter, a circuit is provided for wider bandwidth to eliminate the feedback stability issue and pin out for compensation circuit. A pair of transistors are connected in series between a power input and the bootstrap capacitor, the first transistor is switched synchronously with a low-side transistor of the voltage converter, and a comparator compares a feedback voltage drawn from a feedback node between the pair of transistors with a reference voltage, to control the second transistor to determine to charge the bootstrap capacitor.

FIG. 1 shows a part of a conventional voltage converter, in which a controller chip 10 has a high-side driver 102 and a low-side driver 104 for providing a high-side, drive signal UG and a low-side drive signal LG for a power stage of the voltage converter according to two control signals Ug-signal and Lg-signal, respectively, to switch a high-side transistor 14 and a low-side transistor 16 serially connected between a power source VIN and ground GND, so as to convert an input voltage VIN to an output voltage VOUT. If the supply voltage Vcc of the controller chip 10 is equal to the input voltage VIN, and the voltage converter of FIG. 1 has no diode 12 and bootstrap capacitor CBootstrap, the voltage supplied to the high-side power input Boot of the high-side driver 102 will be the supply voltage VIN. On the other hand, the maximum gate voltage UG of the high-side transistor 14 is equal to the high-side power input voltage VBoot, since the gate voltage UG is provided by the high-side driver 102. As a result, the maximum gate voltage UG will be equal to the supply voltage VIN, and also the input voltage VIN applied to the drain of the high-side transistor 14. Therefore, when the high-side transistor 14 is turned on, and the low-side transistor 16 is turned off, the voltage on the switch node 18, i.e., the source voltage of the high-side transistor 14, will be equal to the input voltage VIN, and as a result, when the high-side driver 102 turns on the high-side transistor 14, the gate voltage UG and the source voltage of the high-side transistor 14 will be equal instantly, causing the high-side transistor 14 to be turned off instantly after it is turned on. For this reason, the conventional voltage converter employs a bootstrap capacitor CBootstrap connected between the high-side power input Boot of the high-side driver 102 and the source of the high-side transistor 14, that is, between the boot node Boot and the switch node 18, for providing a sufficient voltage VBoot between the gate and the source of the high-side transistor 14 after turning on the high-side transistor 14.
As shown in FIG. 1, when the high-side transistor 14 is turned on, its gate voltage will be VIN+VBoot, and there is always a difference VBoot between the gate voltage VIN+VBoot and the source voltage VIN of the high-side transistor 14 due to the presence of the bootstrap capacitor CBootstrap, so that the high-side transistor 14 can remain on. However, when the high-side transistor 14 is turned off and the low-side transistor 16 is turned on, the switch node 18 is grounded, the voltage on the switch node 18 changes to zero, and therefore the charges on the bootstrap capacitor CBootstrap will be released, causing the voltage VBoot to decrease, so that the bootstrap capacitor CBootstrap will need to be charged again to recover the voltage VBoot to its previous level. The conventional voltage converter further employs a diode 12 connected between the bootstrap capacitor CBootstrap and the power source Vcc, so as to charge the bootstrap capacitor CBootstrap by the power source Vcc and prevent reverse current. Usually, a Zener diode is used for the diode 12. If the diode 12 is outside of the controller chip 10, the system design will need an extra element, so it is preferred to set the diode 12 inside the controller chip 10 when designing the controller chip 10. If the diode 12 is inside the controller chip 10, the voltage Vdiode it produces will be greater than that produced by a Zener diode outside of the controller chip 10, which may be about 1 Volt or more, causing the maximum voltage (Vcc−Vdiode) supplied to the high-side power input Boot of the high-side driver 102 to be lower.
FIG. 2 shows a part of another conventional voltage converter, in which a transistor 202 with lower turn-on voltage VON, for example a MOSFET, is set inside the controller chip 20 to replace the diode 12 of FIG. 1, such that the maximum voltage (now Vcc−VON) on the boot pin Boot will be greater. The transistor 202 is controlled by a synchronous signal SYNC, so to be switched synchronously with the low-side transistor 24. When the high-side transistor 22 is turned off and the low-side transistor 24 is turned on, the transistor 202 is turned on by the synchronous signal SYNC, and the power source Vcc could charge the bootstrap capacitor CBootstrap. When the high-side transistor 22 is turned on and the low-side transistor 24 is turned off, the transistor 202 is turned off by the synchronous signal SYNC, to prevent from reverse current flowing from the boot node Boot to the power source Vcc, and the voltage on the boot node Boot remains VIN+VBoot. Although this voltage converter is improved by removing the voltage Vdiode produced by the diode 12, the difference between the voltages on the boot node Boot and on the switch node 18 is fixed at Vcc−Von, lacking of adjustability, and the switching transistor 202 will cause additional switching loss.
FIG. 3 shows a part of yet another conventional voltage converter, in which an operational amplifier 302 and a transistor 304 are added for linear regulation so as to reduce switching loss, a transistor 308 controlled by a synchronous signal SYNC is switched synchronously with the low-side transistor 36, and a feedback voltage is produced by drawing the voltage from the node 306 and dividing with voltage divider resistors R1 and R2 for the operational amplifier 302 to compare with a reference voltage VREF to control the transistor 304. Only when the voltage on the node 306 is too low, the transistor 304 will connect the power source Vcc to the transistor 308 to charge the bootstrap capacitor CBootstrap. When being turned off, the transistor 308 will not cause switching loss. However, because the operational amplifier 302 needs compensation, an additional capacitor 32 is required as the compensation circuit, thereby requiring the controller chip 30 to have an extra pin VDD.

Circuit for charging a bootstrap capacitor in a voltage converter


A process for the preparation of a novel antiozonant and antioxidant, based on functionalized benzotriazole UV absorbers, and the process for the preparation thereof having a general Formula I:

N-alkyl, N′-phenyl-p-phenylene diamines are disclosed in U.S. Pat. Nos. 5,929,166; 5,593,701; 6,329,473; 3,409,586; 3,424,713; 3,542,691; 3,663,505; 3,839,275 and British Patent No. 1,035,262. Sulphur containing para-phenylene diamines are disclosed in U.S. Pat. No. 3,035,014.
A one step acid catalyzed reaction with thiols, formaldehyde and aromatic amines is known in the prior art (J. Org. Chem., 24, 1035 (1959); J. Org. Chem., 28, 2763 (1963) and J. Org. Chem., 30, 28 (1965). Side chain bromination in UV absorbers are disclosed in the literature (S. Yoshida & O. Vogl, Makromol. Chem., 183, 259 (1982); S. Yoshida, C. P. Lillya & O. VogI, Monatshefte Chem., 113, 603 (1982); S. Yoshida, C. P. Lillya & O. Vogl, J. Polym. Sci., Polym. Chem. Ed., 20, 2215 (1982); U.S. Pat. Nos. 6,284,895 and 6,320,056 of P. N. Thanki & R. P. Singh).
As known to those skilled in the art, degradation of rubber from ozone manifests itself by the appearance of (i) cracks perpendicular to the stress in the rubber and (ii) a silvery film on the surface of the article. The attack of ozone is a purely surface phenomenon. The function of the antiozonant depends on its migration to the surface of the rubber article.
Conventional diphenyl diamine antiozonants are widely used in the protection of rubber. Whereas these diphenyl diamines have in the past proved quiet satisfactory, recent developments in rubber technology have resulted in rubber products with extended service life and, therefore, require commensurate protection from ozonolysis. Therefore, there exists a need of new and efficient antiozonants offering extended protection from ozone. The present invention relates to polymeric antiozonants and their use in diene containing polymers.
Amine containing antiozonants are commonly used in diene rubbers to avoid degradation through ozonolysis and oxidation. Common examples of such anti oxidants are N,N-di-substituted p-phenylene diamines. There is a continuing need of superior anti ozonants to further prolong the useful life of these rubber products. The present invention relates to a composition comprising a high molecular weight amine-containing antiozonant that is prepared in a two-step process.
Most thermoplastic polymers and coating compositions are unstable to extended exposure to an ultraviolet light source in atmosphere. Thermoplastics and coatings tend to demonstrate unwanted color changes and reduced mechanical strength upon exposure to UV and thermal radiation. The preliminary effect of ultraviolet radiation on polymers is the formation of free radicals on the polymer chain, which react with atmospheric oxygen. This results in the formation of peroxide groups. Furthermore, decomposition of peroxide groups causes formation of carbonyl groups and chain scission. Irradiation in absence of oxygen causes the increase in crosslinking. Ultimately, this reflects on the mechanical properties and the color of the polymeric materials. In order to prevent or at least retard the damage caused by these factors, stabilizers are added to the plastics.
Antioxidants are tcompounds which, upon addition to the polymers, are capable of preventing or retarding the reactions of degradation caused by heat and light energy in the presence of oxygen. Triazines are one of the most important antioxidants, which are used commercially. There are many patents about the preparation and use of functional antioxidant in polymers and coatings.
Monomeric and low molecular weight antioxidants have limited use due to their properties of migration and leaching. This phenomenon could lead to uneven distribution of antioxidants within the polymeric matrix. Leaching could be even more harmful as the loss of antioxidants from the polymer matrix could lead to extensive thermal and photo-degradation of the substrate. Therefore, in order to prevent the phenomena of migration and leaching, antioxidants with polymerizing ability are being developed. This particular class of stabilizers would have even distribution within the polymer matrix and also they overcome the phenomena of migration and leaching.
U.S. Pat. No. 4,520,171 (Diveley William R. et al.) relates to a new class of polymeric hindered amine light stabilizers based on maleic anhydride modified polyolefins reacted with tetramethyl piperidine derivatives. These materials are more effective than most of the generally used hindered amine light stabilizers. Due to their higher molecular weights and the polyolefin backbone, they are more compatible with polyolefins.
U.S. Pat. No. 4,709,041 (Mehta) discloses 2-(formylphenyl)benzotriazole intermediates that are versatile intermediates, which can be derivatized by reaction of the formyl group to provide a wide variety of ultraviolet-absorbing substituted 2-(2-hydroxyphenyl)-2H-benzotriazoles.
U.S. Pat. No. 4,857,596 (MacLeay et al.) discloses polymer bound antioxidants having antioxidant stabilizer groups chemically bound to polymers or copolymers by an acylaminoimide or diacylhydrazide function. The polymer bound antioxidants are prepared by reacting hydrazido substituted antioxidants with some or all of the anhydride groups of anhydride containing polymers or copolymers. The concentration of the stabilizers bound to the polymer may be readily varied depending upon the application of the polymer. Polymer with high concentrations of bound antioxidants can be used as masterbatches to stabilize other polymer systems.
U.S. Pat. No. 5,420,204 (Valet et al.) discloses light-stabilized copolymer compositions as paint binders. Curable compositions comprising (a) a fluorine- or silicon-containing copolymer, (b) a (meth)acrylic copolymer and (c) at least one curing agent are described, each of the two copolymers comprising functional groups which can react with the curing agent, wherein the fluorine- or silicon-containing copolymer comprises a UV absorber which is chemically bound by reaction with the free reactive groups of the copolymer. These copolymer compositions can be used as paint binders.
U.S. Pat. No. 5,569,716 (Okamoto et al.) discloses a rubber composition composed of (a) a hydrocarbon rubber, (b) a vulcanizing agent and/or crosslinking agent, and (c) a hydrogenated petroleum resin having a bromine number not greater than 10 (g/100 g). The rubber composition exhibits improved process ability over hydrocarbon rubber used alone but has no bad influence on the physical properties and heat resistance of its vulcanization. It is free from any trouble involved in crosslinking with a peroxide which is often used for EPR and EPDM. Therefore, it will find general use in the rubber industry.
U.S. Pat. No. 5,807,963 (Rosenquist Niles R.) discloses the synthesis of high molecular weight stabilizer compounds for stabilizing polymers. A high molecular weight stabilizer compound formed as an ester of 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy-benzene-propanoic acid or structural variants thereof, to impart improved resistance to the effects of ultraviolet radiation to polycarbonate comprising polymers, a process for the preparation of said compound, and articles of manufacture comprising said compound.
U.S. Pat. No. 5,721,298 (Waterman Paul Sheldon) discloses polymers stabilized against degradation by the addition of a liquid composition comprising an organic solvent and at least 40% by weight of triazine UV absorbers.
U.S. Pat. No. 5,834,544 (Lin Chung-Yuan et al.) discloses organic materials stabilized by compounds containing both amine and hindered phenol functional functionalities. The invention relates to compounds containing dual substitutions of an aromatic amine and hindered phenol functionality useful as stabilizers for organic materials.
U.S. Pat. No. 5,997,769 (Tittmann Rolf) discloses novel stabilizer mixtures suitable for stabilizing organic material, especially textile fiber materials, against damage by light, oxygen and heat.
U.S. Pat. No. 5,965,641 (Gugumus) discloses the synthesis of ozone-resistant long-term stabilizers. The invention relates to a process to stabilize an organic polymer against ozone in the ambient air, which comprises adding to the polymer as stabilizer, a monomeric sterically hindered piperidine compound or an oligomeric or polymeric sterically hindered piperidine compound containing one or several triazine units or a secondary sterically hindered piperidine compound.
U.S. Pat. No. 5,990,310 (Barrows Franklin H. A) discloses a method for the preparation of substituted triazines includes reacting a phenylazoaniline with a cyanuric halide to produce a (phenylazo)phenylamino-1,3,5-triazine followed by reduction to form an aminoanilino-1,3,5-triazine. The aminoanilino-1,3,5-triazine can be alkylated under reducing conditions to produce an N-alkyl-phenylenediamino-1,3,5-triazine such as 2,4,5-tris-[N-alkyl-p-phenylenediamino]-1,3,5-triazine, which is useful as an antiozonant in rubber and other polymer formulations.
U.S. Pat. No. 6,046,263 (Rasberger Michael) discloses the use of liquid antioxidants as stabilizers. The described compositions can be used as liquid antioxidants in organic materials.
U.S. Pat. No. 6,284,895 (Thanki, et al.) discloses the use of bromo-functionalized benzotriazole UV absorbers.
U.S. Pat. No. 6,306,939 (Gupta Ram Baboo et al.) discloses a novel carbamate containing trisaryl-1,3,5-triazines and the use thereof as an ultraviolet light absorber. In particular, the presently claimed compounds comprise a carbamate triazine polymer, which either alone or in combination with other additives, including other ultraviolet light absorbers and stabilizers, can be used in stabilizing a polymeric film or molded article from degradation due to exposure to actinic radiation.
U.S. Pat. No. 6,297,378 (Gupta Ram B. et al.) discloses a novel process for making 2-(2-hydroxy-4-alkoxyphenyl)-4,6-bisaryl-1,3,5-triazine and 2-(2,4-dialkoxyphenyl)-4,6-bisaryl-1,3,5-triazine compounds directly from 2-chloro-4,6-bisaryl-1,3,5-triazine compounds with 3-alkoxyphenol, 1,3-dialkoxylbenzene compounds or mixtures thereof.
U.S. Pat. No. 6,492,521 (Sassi Thomas P.) discloses hindered amine light stabilizers based on multi-functional carbonyl compounds and methods of making same.
U.S. Pat. No. 6,362,278 (Pfaendner, Rudolf et al.) discloses a process for stabilizing and concurrently compatibilizing plastics or plastic compositions by incorporating polymeric compounds obtained by reacting a compound selected from the group consisting of the sterically hindered phenols, sterically hindered amines, lactones, sulfides, phosphites, benzotriazoles, benzophenones and 2-(2-hydroxyphenyl)-1,3,5-triazines, which are compounds containing at least one reactive group, with a compatibilizator.
U.S. Pat. No. 6,448,208 (Dubs, Paul et al.) discloses the synthesis of liquid polyfunctional additives.
U.S. Pat. No. 6,369,267 (Toan, Vien Van et al.) discloses the synthesis of polyoxyalkylene substituted, bridged triazine, benzotriazole and benzophenone derivatives as UV absorbers. Triazine, benzotriazole and benzophenone derivatives, which are substituted or bridged with polyoxyalkylene groups, and their use as UV absorbers in photographic materials, such as inkjet inks and printing inks, transfer prints, paints and varnishes, organic polymeric materials, plastics, rubber, glass, packaging materials, sunscreens of cosmetic preparations and skin protection compositions, are disclosed.
U.S. Pat. No. 6,368,520 (Gugumus) discloses a synergistic stabilizer mixture.
U.S. Pat. No. 6,365,652 (Gupta Ram Baboo et al.) discloses an amido or carbamate substituted trisaryl-1,3,5-triazines and the use thereof to protect against degradation by environmental forces, inclusive of ultraviolet light, actinic radiation, oxidation, moisture, atmospheric pollutants and combinations thereof. The new class of trisaryl-1,3,5-triazines comprises an aryl ring attached to the triazine ring substituted with a group comprising a bondable amido/carbamate containing group para- to the point of attachment to the triazine ring. These materials may, under the appropriate circumstances, be bonded to formulations comprising coatings, polymers, resins, organic compounds and the like via reaction of the bondable functionality with the materials of the formulation. A method for stabilizing a material by incorporating such amido or carbamate substituted trisaryl-1,3,5-triazines is also disclosed.
U.S. Pat. No. 6,492,518 (Desai S. M. et al.) relates to Tinuvin P-hindred amine light stabilizer and derivatives thereof.
Buechner et al. (DD 273644 A1 22 Nov. 1989, 4 pp) discloses multivalent lubricant additives on the basis of aminomethylated benzotriazole derivatives, prepared by diazotization of o-phenylenediamine and subsequent aminomethylation of the resulting reaction products containing organic and inorganic transition-, by- and intermediate-products in the reaction medium.
Konstantinova, A. et al. ("Synthesis and application of UV stabilizers for polymeric materials based on triazinylaminobenzotriazole" Polym. Degrad. Stab., 43, 187 (1994)) discloses the synthesis of four derivatives of triazinylaminobenzotriazole, containing a polymerizable allyloxy group. The compounds were characterized by elemental analysis, TLC, IR, UV and 1H NMR spectra. The spectral (absorption and fluorescence) characteristics of the compounds have been investigated, showing that 45–85% of the compounds are bound. Maximum stabilizing effect is achieved with 1 wt % initial concentration of the stabilizer.
The main objective of the present invention to provide a process for the preparation of novel derivatives of a combination of antioxidant and antiozonant, which can fulfill the prerequisites of a polymer stabilizer and can be used with other polymer stabilizers.
Another object of present invention is the preparation of compounds having antioxidant as well as antiozonant properties.
Yet another object of present application is to generate an economic, as well as high yielding, process of preparation of derivatives with antiozonant properties.
Moreover, this class of combination of benzotriazoles and diamines is known to be compatible with polyolefins, polycarbonate, polystyrene and diene-elastomers and can even be added in an additive proportion to obtain desired thermal stability of various other polymers.

Antiozonant based on functionalized benzotriazole UV absorbers and the process thereof

Abstract: wherein R1 and R2 are C1 to C8 linear or branched alkyl; R3 is hydrogen, tert-butyl; X1 is select the group consisting of hydrogen, halogen, tert-butyl and C1 to C12 alkoxy.

Council of Scientific and Industrial Research


The present invention provides a percutaneous absorption preparation which has excellent pressure-sensitive adhesive characteristics and exerts excellent percutaneous absorption property. A crosslinking agent is added to a solution of an acrylic copolymer prepared by copolymerizing a (meth)acrylic acid alkyl ester with a functional monomer, and the acrylic copolymer is partially crosslinked. A composition containing the crosslinked acrylic copolymer is pulverized to prepare a pressure-sensitive adhesive solution comprised of the acrylic copolymer containing crosslinked acrylic copolymer particles. Thereafter, a drug for percutaneous absorption use, a percutaneous penetration enhancer are added to the pressure-sensitive adhesive solution, thereby producing the percutaneous absorption preparation.

In recent years, percutaneous absorption adhesive preparations for external use such as various types of cataplasmas and tapes have been developed using ointment bases and pressure-sensitive adhesives, as percutaneous absorption preparations for use in the administration of drugs into the living body through the skin.
As the method for effectively releasing drugs from these adhesion type percutaneous absorption preparations and efficiently effecting their absorption by the living body from the skin, various methods have been proposed in which, for example, concentration of the drug to be contained is increased or a percutaneous penetration enhancer is jointly used. These methods improve percutaneous absorption of drugs, but the pressure-sensitive adhesive property of the percutaneous absorption preparation is frequently reduced to cause a so-called stringiness and adhesive residue on the skin surface.
As means for resolving these problems, various methods have been proposed, such as a method in which fine powder silica is added to a pressure-sensitive adhesive (JP-A-2-295565; the term "JP-A" as used herein means an "unexamined published Japanese patent application") or a method in which pressure-sensitive characteristics are controlled by making an ointment base into gel form through crosslinking of a pressure-sensitive adhesive (JP-A-3-220120).
Of these methods, the method in which fine powder silica is added to a pressure-sensitive adhesive is used in various field, because it is generally known that fine powder silica acts as a rheology agent to change flow characteristics of pressure-sensitive adhesives.
However, the method in which fine powder silica is added cannot improve pressure-sensitive adhesive characteristics in some cases depending on the formulation composition and formulation method of pressure-sensitive adhesives. Particularly, decrease in the viscosity of pressure-sensitive adhesives cannot be prevented when a polar substance such as polyethylene glycol is added in a large amount as a percutaneous penetration enhancer.
On the other hand, the method in which entire portion of a pressure-sensitive adhesive is crosslinked by external crosslinking to make it into gel form is markedly excellent in view of the point that the pressure-sensitive adhesive characteristics can be controlled even when a percutaneous penetration enhancer and other additives are used in a large amount.
This method, however, also cannot be used in the case where the percutaneous absorption preparation contains a substance having a crosslinking inhibition action, because the pressure-sensitive adhesive cannot fully be crosslinked. In particular, when a generally and frequently used multifunctional isocyanate is used as a crosslinking agent, addition of a drug or additive having a hydroxyl group, an amino group, a carboxyl group or a mercapto group to the pressure-sensitive adhesive causes crosslinking inhibition. For the reason, the drugs and additives having these functional groups cannot be used.
In addition, techniques in which a percutaneous absorption preparation is produced by making a pressure-sensitive adhesive into granular form are disclosed for example in JP-B-58-12255 (the term "JP-B" as used herein means an "examined Japanese patent publication") and JP-B-58-23367, but these techniques have a difficulty in obtaining appropriate pressure-sensitive adhesive characteristics in the case where a percutaneous penetration enhancer and other additives are used in a large amount.


The present invention relates to a method for the specific detection and/or identification of Enterococcus species, in particular Enterococcus faecalis and/or Enterococcus faecium, using new nucleic acid sequences derived from the ITS (Internal Transcribed Spacer) region. The present invention relates also to said new nucleic acid sequences derived from the ITS region, between the 16S and 23S ribosomal ribonucleic acid (rRNA) or rRNA genes, to be used for the specific detection and/or identification of Enterococcus species, in particular of Enterococcus faecalis and/or Enterococcus faecium, in a biological sample. It relates also to nucleic acid primers to be used for the amplification of said spacer region of Enterococcus species in a sample.

The genus Enterococcus includes currently 27 described species. From the human clinical point of view, E. faecalis and/or E. faecium are the most important species: E. faecalis, and E. faecium together make up 95% of all nosocomial enterococcal infections distributed respectively as 80 to 90% and 5 to 10%. Occasionally E. casseliflavus and E. gallinarum are isolated.
Enterococci are increasingly recognized as common causes of infection that become difficult to treat because of both inherent and acquired antibiotic resistance.
Effective control of E. faecalis and/or E. faecium within the hospital and community requires more aggressive measures that include earlier diagnosis of colonized patients, in other words, that include a step of screening.
Moreover, several of the recently described species do not conform to the phenotypic characteristics used up to now for their identification. It is therefore necessary and urgent to provide more rapid methods of detection and/or identification, using probes and/or primers more sensitive and more specific.

Detection, identification and differentiation of eubacterial taxa using a hybridization assay


A method for registering a wireless communication device at a base device may include the steps of: transmitting from a wireless authentication device a piece of authentication information; receiving at the wireless communication device the piece of authentication information, e.g., using in-band communication; transferring the piece of authentication information from the wireless communication device to the base device; analyzing at the base device the transferred piece of authentication information; and incorporating the wireless communication device into a network depending on the result of the analysis. A corresponding system and to a use thereof are also provided.

Nowadays control units, sensors, actuators are increasingly connected to one another, or networked, wirelessly in order to ensure the greatest possible flexibility. In this situation it is also simpler to carry out maintenance on the units or sensors because for example in the case of a malfunction there is no need to open any cable ducts etc. but merely the unit directly. Open protocols such as IEEE 802.11 WLAN, IEEE 802.15.4, Bluetooth, ZigBee or also Wireless HART are normally used in order to connect the aforementioned control units, sensors, etc. In order where possible to avoid any manipulation of the sensors or instructions to the control units during the wireless connection the communication from the control unit or sensor is cryptographically encoded by the corresponding point interface, for example through a WLAN connection using TKIP or CCMP, or in the case of 802.15.4 using AES-CCM. In order to connect a control unit, a sensor or similar to a wireless station and to establish an encrypted connection the control unit, the sensor or the wireless communication device in general must be configured such that the appropriate encryption is used, in other words for example that a cryptographic key is set up. The setup of such a key is also referred to as bootstrapping or pairing.
It is known from US 2006/282885 that an administrator unit of a wireless unit to be configured wirelessly provides a proof of authority. The wireless unit is configured by the administrator unit using the proof of authority provided by the administrator unit.
It is furthermore known to conduct an in-band communication during a weakly protected phase. For this purpose, the corresponding wireless communication unit to be set up does however require special modified transfer methods. Finally, it is known to conduct a pairing secured by an out-of-band channel, such as for example human interaction (in other words entering or checking a PIN, etc.).
Disadvantageous in this case is the fact that the aforementioned methods require a high degree of effort and are complicated in design, particularly when used in the industrial sector because a large number of wireless communication devices are set up there. In this situation it is at the same time necessary that the pairing takes place in protected or secured fashion because the security configuration parameters are set up in the process.

Method for registering a wireless communication device at a base device and corresponding system


Semiconductor devices and methods of forming the semiconductor devices using an HTS (High Temperature Superconductor) layer in combination with a typical diffusion layer between the dielectric material and the copper (or other metal) conductive wiring. The HTS layer includes a superconductor material comprised of barium copper oxide and a rare earth element. The rare earth element yttrium is particularly suitable. For semiconductor devices having other semiconductor circuits or elements above the wiring, a capping layer of HTS material is deposited over the wiring before a cover layer of dielectric is deposited.

As is well known by those skilled in the art, a continuing goal in manufacturing and production of semiconductors is a reduction in size of components and circuits with the concurrent result of an increase in the number of circuits and/or circuit elements such as transistors, capacitors, etc., on a single semiconductor device. This relentless and successful reduction in size of the circuit elements has also required reduction in the size of the conductive lines connecting devices and circuits. However, as the conducting lines are designed to be smaller and smaller, the resistance of the interconnects increases.
In the past, aluminum was used as the metal interconnect lines and silicon oxide as the dielectric. However, newer manufacturing techniques now favor copper as the metal for interconnect lines and various low-k materials (organic and inorganic) are favored as the dielectric material. Not surprisingly, these material changes have required changes in the processing methods. In particular, because of the difficulty of etching copper without also causing unacceptable damage to the dielectric material, the technique of forming the metal interconnect lines has experienced significant changes. Namely, whereas aluminum interconnects could be formed by depositing a layer of aluminum and then using photoresist, lithography, and etching to leave a desired pattern of aluminum lines, the formation of copper interconnect lines are typically formed by a process now commonly referred to as a damascene or dual damascene process. The damascene process is almost the reverse of etching, and simply stated, an aperture such as a trench, canal or via is cut, etched or otherwise formed in the underlying dielectric and is then filled with metal (i.e., copper).
Unfortunately, although copper has the advantages discussed above, it readily diffuses into dielectric material used in the manufacture of semiconductor devices. Diffusion of copper into the dielectric materials of a semiconductor deice can cause serious reliability problems including electrical shorts. Therefore, it is typical to form a diffusion barrier layer between the copper used for conductors and leads and the dielectric material of a semiconductor device. Typical barrier layers may be formed of refractory metals and nitrides of these metals. Some examples of prior art barrier layers include Ta (tantalum), TaN (tantalum nitride), Ti (titanium), TiN (titanium nitride) and various combinations of these metals as well as other metal. The diffusion barrier layer is typically formed on the bottom and sidewalls of the trenches and vias of the copper interconnects to prevent the copper from diffusing into the surrounding silicon dioxide as other dielectric material. In addition, according to the prior art a capping layer of a suitable material, such as silicon nitride, could be deposited as a cover layer over the complete structure including the conductor areas and the dielectric layer before another layer or level of dielectric structure was deposited.
Unfortunately, the traditional diffusion barrier materials have poor adhesion to copper and may peel away thereby creating poor interface properties including a path for copper to diffuse into the subsequent or cover layer of dielectric material. The same path may also allow moisture and contaminants to diffuse from outside into the copper so as to form porous copper oxide. In addition, these barrier materials also create high electrical resistance at small geometrics such as below 300 Å.
U.S. Pat. No. 6,541,136 issued to Kwan, et al. and entitled "Superconducting Structure" discusses superconducting structures that include "rare earth-barium-copper oxide, and especially yttrium-barrier-copper oxide."
U.S. Pat. No. 5,629,268 issued to Tanaka, et al., and entitled "Process for Preparing a Layered Superconducting Structure" also discusses the preparation of a layered superconducting structure based on material that includes barium copper oxide combined with rare earth elements including yttrium.
U.S. Pat. No. 6,518,648 issued to Lopatin and entitled Superconductor Barrier Layer for Integrated Circuit Interconnects provides an integrated circuit that includes a high temperature semiconductor material such as yttrium barium copper oxide as a barrier layer.

Copper wiring with high temperature superconductor (HTS) layer

Taiwan Semiconductor Manufacturing Company, Ltd.


An optoelectronic system including an optoelectronic assembly for receiving and/or transmitting optical data signals, optic means for being optically coupled to the optoelectronic assembly, and an optical fiber coupling device for coupling the optic means and at least one of the optoelectronic devices which form part of the assembly. The coupling device includes a housing for being positioned adjacent the assembly relative to the optoelectronic device and, significantly, latching means movably positioned within the housing for initially engaging the optoelectronic device and thereafter for engaging the incoming optic means (e.g., optical fiber connector) when the optic means is positioned within the coupling device's housing. Keying and shutter means are also provided as part of the coupling device.

As is known, the use of optical fiber as a transmission media is growing at an accelerating rate, including within the information handling system (computer) industry. The advantages of optical fibers over other forms of transmission media are well known. The potential bandwidth (or message carrying capacity) of optical fibers is extremely high. Systems using optical fibers are resistant to electro-magnetic interference which sometimes plagues systems having electrical cables. In addition, optical fiber cabling offers a higher degree of data security than such electrical cables, as it is more difficult for unauthorized personnel to tap or access an optical fiber cable without being detected.
Optical fiber devices use single or multiple strands of fibers each having an inner circular glass core coated with an circumferential cladding having a different index of refraction. Light is transmitted along the core and totally reflected from the interface between the core and cladding. Such devices can be used as transmission lines for transmitting and/or receiving, information bearing light energy.
Typically, transmission lines terminate in optical fiber connectors, such as those referred to in the industry as SC connectors, each of which include as part thereof an outer housing wherein there is positioned the terminating end of the optical fiber. This terminating end is fixed within a ferrule, typically of ceramic material, the ferrule being resiliently oriented such that is can be slightly compressed when the connector is located within a receiving module assembly or the like. Such connectors are illustrated and described in U.S. Pat. No. 4,953,929, and in the aforementioned copending application Ser. No. 07/874,162, both of which are incorporated herein by reference. Attention is also particularly directed to U.S. Pat. No. 5,005,939, wherein an optoelectronic assembly designed to receive a duplex optical fiber connector is defined in detail, said patent also incorporated herein by reference. By the term module as used herein is meant to include an assembly as defined in 5,005,939, while the term connector is meant to include those such as the aforementioned SC type (including when same are retained in a suitable, accommodating adapter as defined in 4,953,929) as well as those of the duplex variety wherein two optical fiber terminal ends (and ferrules) are retained within a singular, common housing (one such example illustrated and described in 5,005,939).
There presently exist in the industry various coupling devices which are designed for coupling in an end-to-end orientation optoelectronic assemblies or modules with associated optical fiber connectors. Due to manufacturing tolerances, however, precision alignment between such structures is often difficult. The connector assembly as defined in Ser. No. 07/874,162 is designed to overcome many such tolerance problems, primarily when attempting to mate two individual SC-type connectors with a singular module, by enabling a degree of flexibility of movement of various parts during connector insertion within a receiving coupling device (shroud). Similarly, the adapter defined in 4,953,929 enables relative movement of the two contained connectors during such insertion. Clearly, both of these structures overcome many of the tolerance problems associated with rigidly fixed embodiments such as known duplex connectors having a singular housing with two encased ferrules.
As defined herein, the present invention provides a new and unique coupling device for optically coupling an optoelectronic module (or assembly) with a mating optical fiber connector such that precision alignment between the connector's optical ferrule(s) and the optoelectronic device (s) retained within the module is attained. Such optoelectronic devices are also often referred to in the industry as optical transceivers, functioning in the manner described in detail in 5,005,939. As understood, the coupling device of the invention is able to substitute for the structure referred to in 5,005,939 as a shroud, and thus may also be referred to as such a component. The invention is of course not to be limited to such usage, as the invention may be used in any situation requiring coupling between such structures as cited above.
One particular application for the invention is as part of what is referred to in the industry as an F.D.D.I. assembly, F.D.D.I. standing for Fiber Distributed Data Interface, and constituting a standard adopted in the industry and approved by the American National Standards Institute (A.N.S.I.). This standard defines the critical requirements for various optoelectronic components, including connectors and modules, which will form part of a high speed optic network. As understood from the following, the invention is able to satisfactorily meet such critical requirements, while assuring a product which is of relatively simple construction and which is also relatively inexpensive to manufacture and purchase. Further, the invention is able to overcome many of the tolerance problems mentioned above by the provision of a structure which is able to accommodate relative movement of the module's optoelectronic devices in addition to movement by the incoming optical fiber connector ends, while, surprisingly, still assuring precision alignment between such components.
It is believed that such a coupling device, particularly one suited especially for utilization within an information handling system, would represent a significant advancement in the art.

Optical fiber coupling device and optoelectronic system utilizing same

International Business Machines Corporation


A method and system for determining the dimensional volume of a package by moving the package on a conveyor belt system over a horizontally disposed strip containing machine-readable indicia indicating units of incremental length along said strip starting from a zero point and by a vertically disposed strip containing machine-readable indicia indicating units of incremental length along said strip starting from a zero point, with a horizontally disposed reader above the horizontally disposed strip to read the uncovered indicia on the horizontally disposed strip and a vertically disposed reader able to read the uncovered indicia on the vertically disposed strip with a computer to determine the lowest uncovered incremental length measurement of the indicia on tile horizontally disposed strip, such measurement being tile width of tile package and the lowest uncovered incremental length measurement of tile indicia on tile vertically disposed strip, such measurement being tile height of tile package, and a device to measure tile package's length as it moves on the conveyor belt system such that the computer calculates tile package's dimensional volume by taking tile product of tile measurements for the length, tile height and tile width of the package. A weigh-in-motion scale is utilized on the conveyor belt system, the output of which is also directed to the computer to calculate tile package's dimensional weight.

1. Field of the Invention
The device and system of this invention reside in the field of systems for the determination of both weight and size dimensions of objects on conveyor belt systems and more particularly relate to an apparatus and method for dimensional volume and weight determination of packages utilizing indicia such as bar codes on measuring strips.
2. Description of tile Prior Art
In the freight forwarding business, domestic and international shippers will often base delivery rates not only on the weight of a package but also on its dimensional volume which taken together are sometimes referred to as "dimensional weight." The determination of dimensional weight to calculate shipping cost has become necessary as the cost of transportation has gone up. Not only is the weight of a package a factor in cost but also the space or volume that that package occupies. Consideration of dimensional volume is especially critical in air cargo shipping where cargo space is especially limited and where weight determination alone would be an inadequate basis for calculating the value of the space taken up by a package. Dimensional volume consideration is also important in surface transportation such as truck or train service where cubicle space is limited.
Conveyor systems have been developed in the prior art which weigh packages moving along the conveyor. Also these conveyor systems can determine a package's dimensional volume for later calculation of "dimensional weight." In many cases the dimensional weight is compared to the actual cargo weight and the larger of these two amounts is used to determine shipping charges. The system which has customarily been used for high-speed dimensional volume determination passes the package along a conveyor system through a dimensioning frame where a first array of infrared lights shines down vertically and a second array of infrared lights shines across horizontally. The infrared lights are detected by sensors disposed on the opposite sides of tile frame. The infrared light beams not blocked by the package are sensed by the sensors which then indicate the dimensional characteristics of the package as it passes through tile frame. These height, length and width measurements are then directed to a computer which calculates tile dimensional volume of the package by adding each package "slice" as blocked by each beam together. The conveyor also utilizes a weigh-in-motion conveyor belt to determine individual package weight. Such infrared device systems are very costly and consequently have not been widely adopted in tile freight industry.
It is also well known in tile art to use bar codes on packages and pass such bar codes by a bar code reader or scanner to get information about tile package such as its contents, destination, etc.
Static and weigh-in-motion scales have been used on conveyors and have been integrated with such infrared scanner systems to automate the process of capturing weight along with package dimensional volume data. Based on such data, delivery rates are calculated and shipping manifests generated.

Package dimensional volume and weight determination system for conveyors


A low-profile, transmissive overhead projector (OHP) employs a novel condensing lens system having a catadioptric Fresnel lens and a dioptric Fresnel lens. Each of the lenses exhibits chromatic aberration, but the dispersion of one lens is selected to cancel out the dispersion of the other, e.g., if the catadioptric lens has negative dispersion then the dioptric lens is selected to have positive dispersion. The mutual cancellation of the dispersion of each lens practically eliminates longitudinal chromatic aberration through the lens system. The lens system provides a fast condensing system which allows collimation, dispersion or concentration of light striking the lens at a high angle of incidence. This characteristic is particularly suited for a low-profile OHP as it allows the light source to be placed directly under, but very close to, the stage area.

1. Field of the Invention
The present invention generally relates to optical lenses and projection systems, and more particularly to an achromatic, Fresnel lens which may be used in a low-profile overhead projector.
2. Description of the Prior Art
Transmissive overhead projectors (OHP's) are known in the art, and are generally comprised of a base having a transparent stage area, a light source inside the base, a projection head mounted above the stage, and a condensing lens system located near the stage for collecting and directing the light towards the projector head. The condensing lens system often takes the form of a Fresnel lens or a two-element Fresnel lens combination, as depicted in U.S. Pat. No. 4,436,393.
Several attempts have been made to decrease the base height of OHP's, for portability and reduced obstruction of the projected image during use. To achieve such a low-profile base, some machines collapse during storage or transportation, then expand open for actual use. Machines of this type are described, for example, in U.S. Pat. No. 4,969,733 and German Patent Application No. 3,519,506. These collapsible OHP's have several disadvantages, however, such as requiring additional parts which increase the complexity of the machine and add to its cost; the moving parts may also adversely affect alignment of the optical elements over time. Finally, there is no base height advantage of these machines over conventional OHP's when in operation.
Other attempts have been made to construct a low base height OHP without the need to collapse the base and optical elements. For example, U.S. Pat. No. 4,741,613 employs a three-element refracting Fresnel lens system to allow the point light source to be very close to the stage. There are several aspects of this invention, however, which could be improved. First, the requirement of three Fresnel lenses necessarily adds to the cost. Secondly, this system does not adequately compensate for the diminished illumination near the periphery of the stage area. Finally, the dispersion (chromaticity) of a conventional Fresnel lens may lead to coloration of the projected image, particularly around the periphery thereof. Most OHP's locate the light source within the base to minimize this effect, but it is noticeable any time the projection head is moved from its optimum position. For example, if the projection head must be lowered to magnify an image or focus it on the projection screen, less red light at the periphery of the stage is captured by the projection lens, leading to a bluish tint at the border of the projected image. Similarly, moving the projection head up (away from the stage) can cause the border to have a reddish tint. This effect (which is even more pronounced in the three-element system of the '613 patent) can be overcome by repositioning the lamp within the base (referred to as "color tuning"), but this involves further user manipulation of the OHP and still requires a subjective judgment regarding the chromaticity of the projected image. Color tunability also adds to the cost of the OHP since it requires a mechanism for repositioning the lamp.
The OHP's disclosed in U.S. Pat. Nos. 4,118,761 and 4,952,053 use folded optical paths to provide a more compact base. In the '761 patent, the light source is also "off-axis," meaning that the apparent location of the light source does not coincide with the center of the stage, i.e., the apparent location is displaced from the normal to the stage center. That device requires a complex optical system including a parabolic reflector to provide collimated light, two planar grooved reflectors, and the condensing lens assembly; it may exhibit a slightly darkened edge, furthest from the light source. In the '053 patent, the darkened edges are compensated for by providing two light sources. The twisted and curved mirrored, grooved prisms are also more difficult to fabricate than flat condensers. Finally, folded optical paths may create problems with full-size stage formats, such as European (A4) styles, since extremely tight folds such as are necessary to achieve a low-profile may cause the light source itself to interfere with the folded light path.
The OHP of the present invention overcomes several of the above limitations by using a novel catadioptric Fresnel lens. While the use of any catadioptric lens in an OHP is in itself novel, catadioptric lenses are known in other art areas. The term "catadioptric" refers to a lens which uses both reflection and refraction to redirect or bend light waves. See, e.g., U.S. Pat. Nos. 2,003,804, 4,859,043 and 5,097,395. As depicted in those patents, catadioptric lenses are useful in collimating light, similar to Fresnel lenses. In U.S. Pat. No. 5,150,966, a catadioptric lens is used to adjust light intensity distribution by discarding light. See also U.S. Pat. No. 4,755,921, which describes a single element catadioptric lens having increased efficiency at high entrance angles, thereby providing a "fast" lens (low f-number) that is suited for compact optical devices.
Chromatic aberration is also a problem with catadioptric Fresnel lenses. The dispersion is caused by the optical properties of the lens material, i.e., its index of refraction varies with the wavelength of the light passing therethrough. There are several techniques, however, for minimizing this effect. For example, attempts have also been made to minimize chromatic aberration in single element lenses, such as by providing discontinuous axisymmetric surfaces, or by using aspheric surfaces. Diffraction gratings may be placed on the lens, including on a Fresnel lens, as depicted in U.S. Pat. No. 5,161,057. See also U.S. Pat. No. 4,337,759, which describes a curved base, catadioptric Fresnel lens with a controlled amount of chromatic dispersion for use as a solar concentrator. Many of the foregoing techniques minimize dispersion only for selected wavelengths, as opposed to the full (visible) spectrum. Most of the techniques (including the '759 patent) also require materials having specific indices of refraction, to achieve a specific focal length with color correction.
In light of the foregoing, it would be desirable and innovative to design a Fresnel lens which is usable in a low-profile OHP. The lens would advantageously be achromatic and constructed of any number of light-transmissive materials having a large range of refractive indices, and efficiently focus the light to the projection lens of the OHP. The condensing system preferably would avoid the use of micro-precision diffraction gratings, and would generally minimize the number of optical elements (such as grooved mirrors), including the number of elements in the condensing lens, but still be compatible with a folded optical path. Provision of such an achromatic lens would greatly reduce or minimize the need for color tuning.

Overhead projector with achromatic fresnel lens

Minnesota Mining and Manufacturing Company


An image processing apparatus able to decrease the number of minute unit graphics, able to achieve an improvement of performance of graphics drawing processing, and able to efficiently generate images, provided with a triangle generator for receiving vertex data from a geometry processor, selecting a plurality of vertexes other than predetermined end points from among 3×3 vertexes forming a mesh, judging whether each selected vertex is valid or invalid based on a distance between the selected vertex and an adjacent vertex, generating triangle data based on validity/invalidity information of each vertex, and outputting the same via a triangle buffer to a triangle drawing device.

1. Field of the Invention
The present invention relates to an image processing apparatus for expressing a model by a combination of unit graphics and a method of the same.
2. Description of the Related Art
Along with the improvement in operating speeds and strengthening of graphics generation functions in recent computer systems, computer graphics (CG) technology for preparing and processing graphics and images using computer resources is being actively researched and developed and being put into practical use.
For example, in three-dimensional graphics, the optical phenomenon when a three-dimensional object is illuminated by a predetermined light source is expressed by a mathematical model and the surface of the object is given shading or brightness or further given a texture based on this model so as to generate a more realistic, three-dimensional-like two-dimensional high definition image. Such computer graphics is now being increasingly actively used in CAD/CAM and other fields of application in science, engineering, manufacturing, etc.
Three-dimensional graphics is generally comprised by a "geometry sub-system" positioned as the front end and a "raster sub-system" positioned as the back end.
The geometry sub-system is a step of geometric processing of the position, posture, etc. of the three-dimensional object displayed on a display screen. In the geometry sub-system, an object is generally treated as an aggregate of a large number of polygons. Geometric processing such as "coordinate conversion", "clipping", and "light source computation" are carried out in units of polygons.
On the other hand, the raster sub-system is a step of painting each pixel composing the object. Rasterization is realized by for example interpolating image parameters of all pixels included inside a polygon based on the image parameters found for every vertex of the polygon. The image parameters referred to here include color (graphics drawing color) data expressed by the so-called RGB format or the like, a z-value expressing a distance in a depth direction, and so on. Further, in recent high definition three-dimensional graphics processing, "f" (fog) for giving a perspective feeling, a texture "t" for expressing the feeling of a material or texture of the object surface to impart reality, etc. are included as mage parameters.
Here, the processing for generating the pixels inside a polygon from the vertex information of the polygon is executed by using a linear interpolation technique frequently referred to as a "digital differential analyzer" (DDA). In the DDA process, the inclination of data to a side direction of the polygon is found from the vertex information, the data on the side is calculated by using this inclination, then the inclination of a raster scan direction (X-direction) is calculated. The change of the parameter found from this inclination is added to the parameter value of a start point of the scan so as to generate an internal pixel.
Summarizing the problems to be solved by the invention, in an image processing apparatus, however, when displaying for example data of a curved surface by tessellating the same into columns of unit graphics, minute unit graphics not reaching even one pixel in size are generated. In a conventional image processing apparatus, this has become one of the factors degrading the operating rate of the graphics generator.
For example, if tessellating a curved surface into columns of triangles, as shown in FIG. 1, the number of minute triangles increases. In some cases, as indicated by the hatching in FIG. 1, triangles not having pixels are generated when drawing. Such a so-called 0 pixel triangle (triangle not including the center of a pixel) causes a drop in the performance of a drawing device.
Further, adaptively generating triangles without using a regular pattern for the curved surface data shown in FIG. 2A for example, as indicated by the hatching in FIG. 2B, a fissure occurs in the curved surface. Accordingly, in a conventional image processing apparatus, where adaptively generating triangles without using a regular pattern, as shown in FIG. 2C, it is necessary to take care not to generate a fissure, so there are the disadvantages that there are constraints on the processing and complex processing is required.

Image processing apparatus and method of same


A multi charged particle beam writing apparatus includes a unit to calculate a predetermined function expression by a correction coefficient that corrects an open area of each opening for forming a beam group, wherein the predetermined function expression minimizes a sum of squared values of all the beam groups, where each of the squared values is calculated by squaring a difference between a current value measured of the beam group and a sum of products for the beam group, where each of the products is obtained by multiplying a corrected open area by the predetermined function expression; a unit to calculate the correction coefficient that corrects the open area by using the predetermined function expression and the current value of the beam, for each beam; and a unit to calculate a current density of each of the multiple beams by the predetermined function expression.

1. Field of the Invention
The present invention relates to a multi charged particle beam writing apparatus and a multi charged particle beam writing method. For example, the present invention relates to a method of obtaining high accuracy of multi-beam writing.
2. Description of Related Art
The lithography technique that advances microminiaturization of semiconductor devices is extremely important as being a unique process whereby patterns are formed in the semiconductor manufacturing. In recent years, with high integration of LSI, the line width (critical dimension) required for semiconductor device circuits is decreasing year by year. The electron beam (EB) writing technique, which intrinsically has excellent resolution, is used for writing or "drawing" a pattern on a wafer, etc. with an electron beam.
As an example using the electron beam writing technique, there is a writing apparatus using multiple beams (multi-beams). Compared with the case of writing using a single electron beam, since a multi-beam writing apparatus can emit multiple radiation beams at a time, it is possible to greatly increase the throughput. In such a writing apparatus of a multi-beam system, for example, multiple beams are formed by letting an electron beam emitted from an electron gun assembly pass through a mask with a plurality of holes, blanking control is performed for each of the beams, and each unblocked beam is reduced by an optical system and deflected by a deflector so as to irradiate a desired position on a target object or "sample" (refer to, e.g., Japanese Patent Application Laid-open (JP-A) No. 2006-261342).
In order to maintain writing accuracy, it is required to calibrate the amount of beam current. In the single beam system, especially in the variable shaping system, since the shot size varies by shot, what is necessary is just to adjust the current density of a beam to be uniform. On the other hand, in the multi-beam system, unlike the single beam system, since the variable shaping is not performed and the shot size of each beam is fixed to be the same size, it is necessary to perform adjustment so that each current amount may be constant. In order to maintain writing accuracy, the beam current amount needs to be calibrated. In the single beam system, since the beam area to be used as a shot in a beam emitted from the electron gun assembly is small, the current density in this area can be almost uniform. However, since many beams in a large area are used in the multi-beam system, it is difficult to make each current uniform. Therefore, it is necessary to correct the irradiation time according to variation of the current amount of each of multiple beams.
In the single beam system, the amount of beam current can be measured by applying irradiation of a beam to the Faraday cup on the stage. Since only one beam is used in the single beam system, measuring can be performed before and after writing processing. However, unlike the single beam system, since a large number of beams are used in the multi-beam system, it may take several days to measure all of the current value of each beam by using the Faraday cup on the stage. Therefore, the writing processing is stopped during the measurement, thereby causing problems of reduction of the apparatus operation rate and reduction of the writing throughput.
Moreover, current density distribution of multiple beams may always change due to temporal change of the cathode of a beam emission source, such as an electron gun assembly, therefore, there is a problem that the current amount of each of the multiple beams will also change.

Multi charged particle beam writing apparatus and multi charged particle beam writing method


A client computing device receives a behavior model corresponding to a user group associated with a user. The behavior model has been trained with monitored user interactions of one or more files associated with the user group. The client computing device further mounts a snapshot of a file and determines, based on the behavior model, which files of the mounted snapshot to transfer to a locally accessible cache. During use of the client computing device, the client computing device may determine whether the mounted snapshot is accessible. If the mounted snapshot is not accessible, the client computing device may selectively delete, based on the behavior model, one or more of the files stored in the locally accessible cache. If the mounted snapshot is accessible, the client computing device may update the one or more files of the locally accessible cache with monitored user interactions with the mounted snapshot.

Businesses recognize the commercial value of their data and seek reliable, cost-effective ways to protect the information stored on their computer networks while minimizing impact on productivity. A company might back up critical computing systems such as databases, file servers, web servers, virtual machines, and so on as part of a daily, weekly, or monthly maintenance schedule. The company may similarly protect computing systems used by its employees, such as those used by an accounting department, marketing department, engineering department, and so forth. Given the rapidly expanding volume of data under management, companies also continue to seek innovative techniques for managing data growth, for example by migrating data to lower-cost storage over time, reducing redundant data, pruning lower priority data, etc. Enterprises also increasingly view their stored data as a valuable asset and look for solutions that leverage their data. For instance, data analysis capabilities, information management, improved data presentation and access features, and the like, are in increasing demand.
A company may use various cloud technologies to provide online access to files by its employees using client computing devices. For example, a user (e.g., an employee of the company) working on a client computing device, such as a laptop computer, may access a file stored in the cloud, and perform operations on the file as if the file were stored locally on the client computing device. These operations are transparent to the user and the user may not be required to perform any special or extraordinary actions to complete these operations. By having the file stored in the cloud, the user may access the file from any location so long as the client computing device has connectivity to the cloud.
However, there may be instances where the user loses connectivity to the cloud and is unable to continue working on the file. Furthermore, the user may need the file to work on other files that are, in fact, locally stored on the client computing device. For example, the file stored in the cloud may be part of a library or larger repository and, without access to the file, the files that are local on the client computing device may be unable to function in their expected manner. This situation may be particularly prevalent in the software development community, where a library or other repository may be stored in the cloud, and multiple users may need access to the cloud library for developing software local on the client computing device.

Intelligent cache management for mounted snapshots based on a behavior model


An optical homogenizer is disclosed which enables an optical system to obtain the benefits of a high quantum efficiency photon detector without suffering from its non-uniform response. The optical homogenizer has an input end for receiving light emitted from a light source and an output end that produces a relatively uniform distribution of light along a spatial dimension of the photon detector in response to the light source. The optical homogenizer ensures that the photon detector is uniformly illuminated from the output end regardless of where photons from the light source enter the input end.

1. Field of Invention
The present invention pertains to the field of optical systems. More particularly, this invention relates to an optical homogenizer.
2. Art Background
An optical system commonly includes a photon detector which generates an electrical signal in response to photons emitted from a light source. An example of a photon detector is a photo multiplier tube (PMT). A PMT includes a photo-cathode element which emits electrons in response to photons which strike it. A PMT also includes elements for multiplying, i.e. amplifying, the emitted electrons. The output of a typical PMT is an electrical signal that indicates the number of photons that strike its photo-cathode element which in turn indicates the brightness of a light source.
A photon detector is commonly characterized by its quantum efficiency. For example, the quantum efficiency of a PMT indicates the percentage of incident photons that cause photo-electric emission from its photo-cathode element. It is usually desirable to employ a photon detector with a high quantum efficiency. A high quantum efficiency usually yields a more sensitive photon detector because the sensitivity of a photon detector is a product of its quantum efficiency and its gain. A high sensitivity usually yields a higher signal to noise ratio in an optical system. In systems in which signal-to-noise ratio is limited by the Poissonian statistics of photons or photo-electrons, the signal to noise ratio may be improved by a higher quantum efficiency buy not by higher gain.
One type of photon detector known to have a relatively high quantum efficiency is referred to as a side-on PMT. A typical side-on PMT though providing relatively high quantum efficiency also has a non-uniform response along the length of its photo-cathode element. As a consequence, the sensitivity of a side-on PMT usually varies depending upon which area of its photo-cathode element is illuminated. Unfortunately, such a non-uniform response can make light sources of equal brightness appear to have differing brightness. This can cause errors in, for example, an imaging system in which light emanating from an image is scanned into a side-on PMT.


An LED lighting device includes: a resistor R1 configured to output a detection value of an inductor current I1 flowing through an inductor L1 during an ON period of a switching element Q1; a threshold generation section 42 configured to generate a threshold value Vs of the inductor current I1 corresponding to a dimming level; and a switching control section 44 configured to control the switching element Q1 to turn on and off. The switching control section 44 is configured to determine an OFF timing of the switching element Q1 based on comparison between the detection value and the threshold value Vs of the inductor current I1. The LED lighting device increases a period of a switching cycle of the switching element Q1 with decrease of the dimming level.

As a lighting device adapted for lighting a light source composed of LED elements (hereinafter referred to as "LED lighting device"), there has been proposed such a lighting device that includes a chopper circuit so as to adjust (dim) the luminance of the light source. JP2002-231471A discloses a lighting device that can adjust the electric current flowing through an LED light source (hereinafter referred to as "LED current") so as to dim the LED light source by means of PWM control method. In the PWM control method, the duty ratio of a switching element included in the chopper circuit is variably controlled to adjust the LED current, so that the LED light source is lit in a desired luminance. JP2009-301876A discloses a lighting device that utilizes a first dimming signal and a second dimming signal. The first dimming signal is used for determining a dimming level, and the second dimming signal is used for determining a dimming curve. This lighting device is configured to select, based on the second dimming signal, a desired dimming curve from among a plurality of dimming curves stored in a circuit.
JP2010-40400A discloses a lighting device including a chopper circuit and a power factor corrector connected at an input side of the chopper circuit. This lighting device is configured to terminate the operation of the power factor corrector when light output of an LED element becomes lower than a predetermined level. This lighting device thereby can reduce the flicker of the LED element.
In a lighting device including a chopper circuit, energy is charged in an inductor during an ON period of the switching element, and the energy is discharged to flow an electric current during an OFF period of the switching element. The electric current varies in inverse proportion to the inductance of the inductor. Therefore, if the switching frequency is set at a low level (e.g., less than 40 [kHz]) in the lighting device which is configured to adjust the LED current based on the PWM control method, the lighting device has been required to employ a large-sized inductor with large inductance in order to reduce such a time period in which the electric current does not flow through the inductor in the OFF period.
Furthermore, when the switching frequency is set around 30 [kHz] to 40 [kHz], ripple components emerge on a waveform of the LED current to cause a flickering of light emitted by the LED element. This is likely to interfere with infrared signals emitted by a remote controller provided in another equipment. Therefore, to reduce the ripple component, a smoothing capacitor, which is to be connected in parallel with the LED element, has been required to have a large capacity.
For downsizing the inductor and/or the smoothing capacitor, there has been proposed such an LED lighting device that controls the switching element at a high-frequency. However, if the switching frequency of the switching element is set high, the ON period of the switching element may significantly be shortened (e.g., substantially 0) when the dimming level is decreased and the LED current is reduced. As a result, in the LED lighting device with a high switching frequency, when the dimming level is set low, it may be difficult to control the switching operation stably due to a delay time occurred in a control circuit for controlling the switching operation, a performance limit of the lighting device for driving the switching element, a delay time occurred in a gate-driver, or the like. That is, the conventional LED lighting device may be hard to perform stable dimming control when the dimming level is comparatively low.

LED lighting device and illuminating apparatus using the same

Panasonic Intellectual Property Management Co., Ltd.


A gas turbine engine and a method of operating the gas turbine engine according to an exemplary aspect of the present disclosure includes modulating a variable high pressure turbine inlet guide vane of a high pressure spool to performance match a first stage fan section of a low pressure spool and an intermediate stage fan section of an intermediate spool to maintain a generally constant engine inlet flow while varying engine thrust.

The present disclosure relates to gas turbine engines, and more particularly to a 3 spool variable cycle gas turbine engine.
Variable cycle engines power high performance aircraft over a range of operating conditions yet achieve countervailing objectives such as high specific thrust and low fuel consumption. The variable cycle engine essentially alters a bypass ratio during flight to match varying requirements. This facilitates efficient performance over a broad range of altitudes and flight conditions to generate high thrust when needed for high energy maneuvers yet also optimize fuel efficiency for cruise or loiter conditions.

Gas turbine engine with two-spool fan and variable vane turbine


A method for manufacturing a semiconductor stacked body, and a semiconductor element including the semiconductor stacked body includes a semiconductor stacked body, including a Ga2O3 substrate having, as a principal plane, a plane on which oxygen atoms are arranged in a hexagonal lattice, an AlN buffer layer formed on the Ga2O3 substrate, and a nitride semiconductor layer formed on the AlN buffer layer.

Conventionally, a semiconductor element including a semiconductor laminate composed of a Ga2O3 substrate, an AlN buffer layer and a GaN layer is known (see, e.g., PTL 1). According to Patent Literature 1, the AlN buffer layer is formed to have a thickness of 10 to 30 nm by growing an AlN crystal on the Ga2O3 substrate. In addition, the GaN layer, which is formed by growing a GaN crystal on the AlN buffer layer, contains Si as a donor.

Semiconductor stacked body, method for manufacturing same, and semiconductor element


The portable fuel delivery apparatus for temporarily providing fuel to disabled machines, such as motor vehicles. The apparatus comprises a container for housing the fuel, a hose for discharging the fuel from said container, an electric pump inside said container for pumping the fuel from the container through said hose, and a pair of wires to connect said electric pump to a power source.

The present invention relates to a portable device for providing temporary fuel to a disabled motor device. More specifically, the present invention relates to a portable fuel delivery apparatus for temporarily providing fuel to a disabled motor vehicle.
Most cars built in the last twenty-five years, no longer have carburetors, but use fuel injectors instead. The fuel injection system requires the fuel to be delivered to the engine at a higher pressure than required for the carburetors. Accordingly, the high pressure electrical fuel pumps have been steadily replacing the mechanical fuel pumps. When a motor vehicle is disabled, e.g., resulting from an electrical fuel pump failure, the disabled vehicle is towed to a repair shop. Typically the disabled vehicle sits in a lot outside the repair shop until it is ready to be worked on by a mechanic. The problem is getting the disabled vehicle from where it was dropped off in the lot into the repair shop. Therefore, it is desirable to have a device that can be attached to a disable vehicle for enabling the vehicle to be started and driven into the repair shop.


By taking into consideration the combination of the substrate holders in various lithography tools used during the imaging to two subsequent device layers, enhanced alignment accuracy may be accomplished. Furthermore, restrictive tool dedications for critical lithography processes may be significantly relaxed by providing specific overlay correction data for each possible process flow, wherein, in some illustrative embodiments, a restriction of the number of possible process flows may be accomplished by implementing a rule for selecting a predefined substrate holder when starting the processing of an associated group of substrates.

1. Field of the Invention
The present disclosure relates to the field of fabricating microstructures, such as integrated circuits, and, more particularly, to a technique for controlling alignment accuracy and pattern placement precision during lithography processes in forming and patterning stacked material layers.
2. Description of the Related Art
The fabrication of microstructures, such as integrated circuits, requires tiny regions of precisely controlled size to be formed in a material layer of an appropriate substrate, such as a silicon substrate, a silicon-on-insulator (SOI) substrate or other suitable carrier materials. These tiny regions of precisely controlled size are generated by patterning the material layer by performing lithography, etch, implantation, deposition, oxidation processes and the like, wherein typically, at least in a certain stage of the patterning process, a mask layer may be formed over the material layer to be treated to define these tiny regions. Generally, a mask layer may consist of or may be formed by means of a layer of photoresist that is patterned by a lithographic process, typically a photolithography process. During the photolithography process, the resist may be spin-coated onto the substrate surface and then selectively exposed to ultraviolet radiation through a corresponding lithography mask, such as a reticle, thereby imaging the reticle pattern into resist layer to form a latent image therein. After developing the photoresist, depending on the type of resist, positive resist or negative resist, the exposed portions or the non-exposed portions are removed to form the required pattern in the layer of photoresist. Based on this resist pattern, actual device patterns may be formed by further manufacturing processes, such as etch, implantation, anneal processes and the like. Since the dimensions of the patterns in sophisticated integrated microstructure devices are steadily decreasing, the equipment used for patterning device features have to meet very stringent requirements with regard to resolution and overlay accuracy of the involved fabrication processes. In this respect, resolution is considered as a measure for specifying the consistent ability to print minimum size images under conditions of predefined manufacturing variations. One important factor in improving the resolution is the lithographic process, in which patterns contained in the photo mask or reticle are optically transferred to the substrate via an optical imaging system. Therefore, great efforts are made to steadily improve optical properties of the lithographic system, such as numerical aperture, depth of focus and wavelength of the light source used.
The quality of the lithographic imagery is extremely important in creating very small feature sizes. Of at least comparable importance is the accuracy with which an image can be positioned on the surface of the substrate. Typically, microstructures, such as integrated circuits, are fabricated by sequentially patterning material layers, wherein features on successive material layers bear a spatial relationship to one another. Each pattern formed in a subsequent material layer has to be aligned to a corresponding pattern formed in the previously patterned material layer within specified registration tolerances. These registration tolerances are caused by, for example, a variation of a photoresist image on the substrate due to non-uniformities in such parameters as resist thickness, baking temperature, exposure dose and time and development conditions. Furthermore, non-uniformities of the etch processes can also lead to variations of the etched features. In addition, there exists an uncertainty in overlaying the image of the pattern of the current material layer to the etched or otherwise defined pattern of the previously formed material layer while photolithographically transferring the image of the photo mask onto the substrate. Several factors contribute to an imperfect ability of the imaging system to overlay two layers, such as imperfections within a set of masks, temperature differences at the different times of exposure, a limited registration capability of the alignment tool and, as a major contribution to alignment errors, imperfections of the exposure tool itself, such as lens distortions, and distortions caused by the alignment hardware, such as the substrate holder, and the like. The situation becomes even worse when different exposure tools are used for defining subsequent device layers, since then the inherent errors in the exposure tool and related components may vary between the different tools.
Although the same exposure tool might be used for imaging critical device layers, in practice, such restrictions may not allow an efficient overall process flow in a complex manufacturing environment, which typically comprises a plurality of lithography tools for the same device layer. As a result, the dominant criteria for determining the minimum feature size that may finally be obtained are the resolution for creating features in individual substrate layers and the total overlay error to which the above-explained factors, in particular the lithographic process, contribute.
Therefore, it is essential to continuously monitor the resolution, i.e., the capability of reliably and reproducibly creating the minimum feature size, also referred to as critical dimension (CD), within a specific material layer, and to continuously determine the overlay accuracy of patterns of material layers that have been successively formed and that have to be aligned to each other. For example, when forming a wiring structure for an integrated circuit, respective metal lines and vias, which connect two stacked metal regions, may have to be aligned to each other with strict process margins, since a significant misalignment may cause a short between actually non-connected lines, thereby possibly creating a fatal device defect.
Thus, modern advanced process control (APC) strategies strive to reduce respective errors on the basis of the measurement results obtained from previously measured substrates, in order to feed back the mismatch indicated by the measurement data for reducing the alignment error in the next substrate to be processed. APC controllers may have a predictive behavior, which is typically referred to as model predictive control (MPC), which may be convenient when the amount of available measurement data is restricted due to process requirements.
For generating appropriate manipulated values, the measured "overlay" may be separated into individual alignment parameters, such as magnification, translation, substrate rotation, reticle rotation, orthogonality and the like. Consequently, a corresponding exposure tool recipe for aligning the image of a reticle with respect to a specified position of the substrate may contain respective manipulated variables that correspond to the overlay parameters specified above. The manipulated variables may represent so-called controller inputs, that is, any process parameters of the lithography tool which may be adjusted by the controller so as to obtain specified values for the above-specified overlay parameters or control variables, such as magnification, x-translation, orthogonality and the like.
For instance, in controlling the accurate pattern placement of two corresponding device layers, measurement results may be gathered from a stream of a specific number of substrate lots to calculate the alignment parameters, for instance ten alignment parameters of a linear alignment model, which may then be fed back to the lithography tool to expose the next substrate lot. In this way, drifts of the lithography tool or changes in the technology may be corrected. As previously discussed, high volume production lines for semiconductor devices may have to fulfill critical overlay specifications while at the same time reduce overall cycle time per mask layer. For this reason, advanced lithography tools, such as step and scanning tools, may have two substrate holders or chucks to provide alternating processing, i.e., while exposing one substrate, a further substrate is aligned and positioned in the other substrate holder. Since the characteristics of the substrate holders may also have a significant effect on the finally obtained alignment precision, and thus on the exposure of the substrates, respective overlay correction data, i.e., the corresponding linear alignment parameters, may be established separately for each substrate holder in order to enable different corrections for each of the substrate holders. Although significant improvements with respect to overall process accuracy may be achieved, in particular in sophisticated production lines, in which typically a plurality of lithography tools may be used, the degree of alignment accuracy may not be compatible with the quality specifications. Hence, very restrictive constraints may be imposed on the lithography processes, for instance by dedicating tools so that two subsequent critical mask layers may be imaged by the same lithography tool. Consequently, a reduced flexibility in substrate scheduling may occur, thereby contributing to a significant increase of overall cycle time, in particular in high volume production process lines.
The present disclosure is directed to various methods and systems that may avoid, or at least reduce, the effects of one or more of the problems identified above.

Method and system for reducing overlay errors in semiconductor volume production using a mixed tool scenario