A method for fabricating micro-lenses and a method for fabricating micro-lenses by photolithography are provided. The method includes forming a plurality of micro-cavities in a substrate, filling lens material into each of the micro-cavities, and heating the lens material, thereby reflowing the lens material so as to form a plurality of micro-lenses in the substrate. The micro-cavities define a boundary of each of the micro-lenses formed by reflowing the lens material, thereby preventing adjacent micro-lenses from fusing together by reflowing when overheated. The process uses negative photoresist and positive photoresist as micro-cavities and lens material respectively, thereby streamlining the fabrication method and its steps.

1. Field of the Invention
The present invention relates to a method for fabricating micro-lenses, and more particularly, to a method for fabricating micro-lenses by photolithography.
2. Description of Related Art
Presently, micro-lens array has been widely used in the field of image sensor design, such as CCD (charged coupling device) image sensor, and CMOS (complementary metal oxide semiconductor) sensor.
The objective of either the CCD image sensor or CMOS image sensor is to increase the incident light quantity per pixel so as to increase the sensing ability of the image sensor. Micro-lens array technique is frequently used in conjunction with the micro-lens array of the light sensing part per pixel, thereby raising the sensing ability of the high pixel sensing part.
In particular, the frequently-seen manufacturing method of the micro-lens array structure uses polymer thermal reflow to form all kinds of the required micro-lens shapes. However, as the pixel size shrinks or the pixel density increases, the gap between the adjacent micro-lenses will be too small and the temperature of the micro-lens substrate will be non-uniform, thereby causing problems such as incomplete lens thermal melting or improper thermal agglutinations between the adjacent micro-lenses in the conventional thermal reflow.
Referring to FIG. 1a, a first diagram of a conventional micro-lens thermal reflow process is illustrated. As shown in the diagram, when the micro-lens substrate is of non-uniform temperature, which is that the polymer material at a higher level of the substrate has been melted to form an ideal arc-shaped micro-lens 11 and the polymer material 12 at the lower temperature part of the substrate has not, an insufficient thermal reaction may occur, resulting in failure in forming an ideal arc-shaped lens of the polymer material.
Referring now to FIG. 1b, a second diagram of a conventional micro-lens thermal reflow is illustrated. As shown in the diagram, if heating continues following the process of FIG. 1a, the polymer material located at the part of a lower temperature of the substrate can also achieve a sufficient thermal reaction to form an ideal arc-shaped lens 13 by being melted. On the other hand, the micro-lenses located at the higher temperature of the substrate could possibly be thermally fused with adjacent micro-lenses 14.
In summary, it has become an urgent issue for designers in the micro-lens design field to propose a micro-lens manufacturing method to avoid incomplete thermal fusing or problems of agglutinating the adjacent micro-lenses in the conventional thermal reflow due to the undersized interspace of the adjacent micro-lenses and the non-uniform temperature of the micro-lens substrate after the pixel size is shrunk or the pixel density is increased.

Method for fabricating microlenses and process of single photomask pattern-based photolithography


A virtual server set is disclosed, comprising one or more virtual servers for processing user requests, the virtual server set comprising, at least a first processor and a second processor, a memory, a first switch running on the first processor, the first switch to manage a control plane, and, a second switch running on the second processor, to manage a signaling plane and a bearer plane.

A virtual server set may be designated to address user requests. Such a server set will typically include a plurality of processors, a memory, and a virtual switch to manage the input/output routing of the requests, as well as control management of the virtual server set. A data communication switch may be used in a computer network to communicatively couple devices on the network. For example, a switch may route a message to a selected server computer, host, or processor based on a media access control (MAC) address contained as a destination address in the message. In some contexts, the data communication switch may be said to provide packet switching functions.
Denial-of-Service attacks (DoS attacks) are designed to overwhelm the ability of a virtual server set to address user requests. That is, requests are sent in at such a fast rate that the virtual server set assigned to handle the requests cannot keep up, for example has little or no remaining time for handling legitimate requests. The goal of such attacks may be to cause a partial or complete shutdown of the virtual server set.

Method of securing management interfaces of virtual machines


A process for extracting and purifying a protein having an apparent molecular weight of about 69,000 daltons from the outer membrane of the bacterium Bordetella pertussis is provided. The process includes inactivating Bordetella pertussis cells with a bacteriostatic agent, repetitive extraction, and purification of the 69,000 dalton protein from extract by dye ligand chromatography followed by chromatofocusing. The process results in improved yield and stability of the 69,000 dalton protein.

1. Field of the Invention
The invention relates to a process for extracting and purifying a protein having an apparent molecular weight of about 69,000 daltons from the outer membrane of the bacterium Bordetella pertussis. The protein so extracted and purified may be utilized as a component of an acellular pertussis vaccine.
2. Description of the Prior Art
The bacterium Bordetella pertussis is the causative agent of the serious infectious disease known as pertussis or whooping cough. Vaccines which are used to immunize infants and children are composed of whole cells of B. pertussis inactivated with chemical agents or heat. While whole cell vaccines contain the antigenic components necessary to elicit protective immunity, they may also contain substances irrelevant to protection and possibly related to undesirable side effects of immunization.
In an effort to minimize any undesirable side effects of immunization with whole cell vaccines, the pathogenic mechanisms of B. pertussis have been studied to determine which antigenic components contribute to protective immunity. The specific antigens so identified thus could be included in an acellular vaccine which would confer immunity to disease without introducing irrelevant and possibly undesirable substances in the immunization. A number of antigens have been proposed as acellular vaccine components, for example: lymphocytosis promoting factor (LPF; also known as histamine sensitizing factor, islet activating protein, and pertussis toxin), filamentous hemagglutinin (FHA), and fimbrial agglutinogens. (Weiss, A.A. and Hewlett, E.L., 1986, Ann. Rev. Microbiol., 40:661-686.)
Another antigen, associated with the B. pertussis outer membrane, and having an apparent molecular weight of about 69,000 daltons is referred to as the B. pertussis 69K protein or P.69. The B. pertussis 69K protein is immunologically related to similar proteins, having slight differences in electrophoretic mobility, produced by the human pathogen B. parapertussis and the animal pathogen B. bronchiseptica. It has been suggested that the 69K protein would be a protective antigen useful as a vaccine component. The correlation between protection against disease and the presence of specific antibodies was first established for the B. bronchiseptica 68K protein, and the investigation was later extended to the 69K protein of B. pertussis by Novotny et al. (Novotny, P., Chubb, A. P., Cownley, K., Montaraz, J. A., and Beesley, J. E., 1985. Dev. Biol. Stand. 61: 27-41; Novotny, P., Korisch, M., Cownley, K., Chubb, A. P., and Montaraz, J. A., 1985. Infect. Immun. 50: 190-198; Montaraz, J. A., Novotny, P., and Ivanyi J., 1985. Infect. Immun. 47: 744-751; and Novotny, P., Chubb, A. P., Cownley, K., and Montaraz, J. A., 1985. Infect. Immun. 50: 199-206). Others have shown that 69K is protective in certain animal models of pertussis, either by active or passive immunity. Furthermore, antibodies against 69K are present in sera of humans who have recovered from pertussis. The 69K protein has the properties of a B. pertussis agglutinogen, and can act as an adhesin, causing attachment to mammalian cells. The 69K protein is expressed coordinately with LPF, FHA, and other specific factors under the control of a genetic locus related to B. pertussis virulence, and is expressed only in virulent strains. Finally, the 69K protein has been reported to be a component of an acellular pertussis vaccine successfully utilized in Japan. (Aoyama, J., Murase, Y., Kato, M., Iwai, H., and Iwata, J., 1989, Am. J. Dis. Child. 143: 655-659; Shahin, R. D., Brennan, M. J., Li., Z. M., Meade, B. D., and Manclark, C. R., 1989, J. Exp. Med. (in press); Brennan, M. J., Li, Z. M., Lowell, J. L., Bisher, M. E., Steven, A. C., Novotny, P., and Manclark, C. R., 1988. Infect. Immun. 56: 3189-3195; Charles, I. G., Dougan, G., Pickard, D., Chatfield, S., Smith, M., Novotny, P., Morrissey, P., and Fairweather, N. F., 1989. Proc. Natl. Acad. Sci. USA 86: 3554-3558; Leininger - Zapata, E., Brennan, M. J., Kenimer, J. G., Charles, I., Fairweather, N., and Novotny, P. 1989, Abstr. Amer. Microbiol. p.51, abstr. B-123; and Shahin, R., Brennan, M. J., and Meade, B. D., 1989. Abstr. Amer. Soc. Microbiol. p.51, abstr. B-125.)
In order to employ the 69K protein as a component of an acellular pertussis vaccine, a method is required for the efficient purification of the protein applicable to commercial production scale. Previously described methods, however, have several disadvantages for adaptation to large scale.
Novotny et al (Infection and Immunity 50: 199-206 (1985); EP 0 162 639) describe a method for extracting and purifying 69K protein from whole B. pertussis cells. The method described by Novotny et al includes suspending the whole B. pertussis cells in water, adjusting to pH3 with a buffer, incubating at 37.degree. C. for approx 18 hours to release proteins including the 69K protein from the whole cells, removing the cells by centrifugation leaving a protein extract, precipitating the protein extract with acetone at -20.degree. C., and centrifuging the precipitate to separate the precipitated proteins from non-proteinaceous material remaining in solution. The resulting protein extract was chromatographed on a DEAE - Trisacyl ion-exchange column and eluted a with salt gradient. Material not retained by the ion-exchange column was subjected to isoelectric focusing with a preparative isoelectic focusing gel or chromatofocusing. Protein containing fractions as recognized by an anti-69K protein monoclonal antibody were then applied to a monoclonal antibody column which was then eluted with 6M urea to produce the 69K protein.
This method would not be conducive to commercial production of the 69K protein, however, because it requires 18 hours for extraction of the protein from cells, utilizes acetone, a dangerous solvent, in the precipitation step, requires an ion-exchange chromatography column run lasting 20 hours, and utilizes a cumbersome preparative isoelectric focusing procedure lasting 16 hours. Further, the resulting protein preparation is not completely purified until after an additional step where it is passed through an affinity column utilizing anti-69K monoclonal antibodies linked to a polymeric support and eluted utilizing a harsh 6M urea. Finally, the protein is unstable throughout the purification process resulting in some degradation of the protein during purification.
Brennan et al [Infection and Immunity 56: 3189-3195 (1988)] also describe a method for extracting and purifying the B. pertussis 69K protein from whole B. pertussis cells. The method described by Brennan et al includes suspending live B. pertussis cells in a phosphate buffered saline solution, incubating at 60.degree. C. for 1 hour to release the proteins from the cells, removing the cells by centrifugation leaving a protein extract and dialyzing the protein extract so obtained in a tris-buffered saline solution which contains the protease inhibitors ethylenediaminetetraacetic acid (EDTA) and phenylmethylsulfonylfluoride (PMSF), and Brij 35, a detergent. The extract is then applied to a fetuin-Sepharose column to remove pertussis toxin, followed by a monoclonal antibody affinity column, which is eluted with 6M urea to produce the 69K protein. As with the method disclosed by Novotny et al, this method is subject to some limitations which make it relatively difficult to carry out efficiently on a commercial scale. For example, comparing the multiple incubation extraction steps of the present invention to the single step of Brennan et al demonstrates that the single incubation extraction step results in a very incomplete extraction of 69K protein from the cells. Further, the method disclosed by Brennan et al would require the large scale use of toxic and expensive chemicals if it were practiced on a commercial scale. Finally, both the Novotny et al and Brennan et al methods require the use of a monoclonal antibody affinity column.
In general, methods employing monoclonal antibody affinity columns are not suited to commercial production because the antibodies are not commercially available and must be generated in a lengthy procedure of immunization followed by hybridoma production and screening. The antibodies must then be purified and linked to the affinity support, all of which is both labor and time consuming. Furthermore, elution from the affinity columns involves high concentrations of urea which is detrimental because urea is a known denaturing agent and can alter protein structural characteristics.
A third method for extracting and purifying 69K protein from whole B. pertussis cells is described by Burns et al in U.S. Ser. No. 7/308,864 filed Feb. 10, 1989, now U.S. Pat. No. 5,101,014, and in abstracts of American Society of Microbiology, p. 51, abstract B-126 (1989). This method includes suspending live B. pertussis cells in a tris-buffered saline solution which contains PMSF and sodium azide, incubating at 60.degree. C. for 1 hour to release proteins from the cells, removing the cells by centrifugation leaving a protein extract, and dialyzing the protein extract so obtained in a tris-buffered saline solution which contains the protease inhibitor, PMSF, at substantial concentration (1 mM). The extract is then applied to a DEAE - sepharose ion-exchange column which is eluted with a salt gradient. The eluate is dialyzed and then passed to a dye ligand chromatography column (Affi-gel Blue (Bio-Rad)) and eluted with a high concentration of urea in the presence of a detergent to produce the 69K protein. As with the Novotny et al and Brennan et al methods, this method is also not suitable to commercial production of the 69K protein because it requires the presence of protease inhibitors at substantial concentration (e.g. 1 mM PMSF) throughout the process to preserve the 69K protein from proteolytic degradation. For adaptation to large scale, the use of large volumes of buffers containing such toxic and expensive substances is a disadvantage, and the complete removal of these substances from the final product must be assured. In addition, the urea and detergent materials used to elute the protein from the dye ligand column may adversely affect the protein structure via denaturation.
Accordingly, it is a object of the present invention to provide an improved process for the extraction and purification of 69K protein from whole B. pertussis cells, which process is suitable to commercial production of the protein. It is another object to provide a process in which the yield of protein is increased. It is another object to provide a process in which the stability of the 69K protein is increased. It is a further object to provide a process in which toxic protease inhibitors or harsh denaturing agents such as a high concentration of urea are not employed.

Process for purification of a 69000 dalton antigenic protein from Bordetella pertussis


A method and device controls a printer or copier to generate a plurality of marks that are assembled into a coherent marking band that is then inked by the toner. A sensor measures the marking band. The printer or copier are controlled based on the output of the sensor.

1. Field of the Invention
The invention concerns a method to control a printer or copier, in that marking data for toner markings for a character generator are stored in an image control, and in that the character generator generates in an intermediate carrier a latent image corresponding to the marking data that is inked with toner material in the further course, whereby toner marks are generated on the intermediate carrier. Furthermore, the invention concerns a device to implement this method.
Furthermore, the invention concerns a method to control a printer or copier using an optical reflex sensor, as well as a device for this.
2. Description of the Related Art
In order to print a print image on a print medium (for example paper) with consistent inking, a permanent monitoring and regulation of the electrophotographic or electromagnetic processes is necessary. For this monitoring and regulation, different toner marks adapted to the respective processes are applied to the intermediate carrier (that is, for example, an organic photoconductor band, also called an OPC band (OPC organic photoconductor)) or to a transfer band; these toner marks are scanned with the aid of sensors and the results used to control the print process. For example, the blackening of the toner mark can be measured with the aid of a reflex sensor. Another possibility is to detect the toner layer thickness with the aid of a capacitive layer thickness sensor. Another method utilizes the electric toner charge, whereby the charge potential is measured with the aid of a potential sensor. The problem exists in these procedures to apply different markings to the intermediate carrier independent of the print image to be printed and independent of a temporal control, and to synchronize these toner markings with the evaluation by the sensor or sensors.

Method for controlling a printer or copier using a toner mark band and reflex sensor working according to the triangulation principle


A manufacturing method of a semiconductor structure includes the following steps. Gate structures are formed on a semiconductor substrate. A source/drain contact is formed between two adjacent gate structures. The source/drain contact is recessed by a recessing process. A top surface of the source/drain contact is lower than a top surface of the gate structure after the recessing process. A stop layer is formed on the gate structures and the source/drain contact after the recessing process. A top surface of the stop layer on the source/drain contact is lower than the top surface of the gate structure. A semiconductor structure includes the semiconductor substrate, the gate structures, a gate contact structure, and the source/drain contact. The source/drain contact is disposed between two adjacent gate structures, and the top surface of the source/drain contact is lower than the top surface of the gate structure.

1. Field of the Invention
The present invention relates to a semiconductor structure and a manufacturing method thereof, and more particularly, to a semiconductor structure including a source/drain contact recessed by a recessing process for improving the process window and a manufacturing method thereof.
2. Description of the Prior Art
The development of semiconductor integrated circuit technology progresses continuously and circuit designs in products of the new generation become smaller and more complicated than those of the former generation. The amount and the density of the functional devices in each chip region are increased constantly according to the requirements of innovated products, and the size of each device has to become smaller accordingly. As shown in FIG. 1, in a traditional semiconductor structure 100, a plurality of gates 130 are disposed on a substrate 110, a gate protection layer 131 is formed on each of the gates 130, and a self-aligned contact structure 141 is formed between two adjacent gates 130. The self-aligned contact structure 141 is formed by filling an opening formed between the two adjacent gates 130 with a conductive material and performing a chemical mechanical polish (CMP) process, and the self-aligned contact structure 141 may be formed corresponding to a source/drain (not shown) between the gates 130. The self-aligned contact structure 141 is electrically isolated from the gates 130. After the CMP process mentioned above, top surfaces of the self-aligned contact structure 141, the gate protection layer 131, and a first gate contact 142 formed on another gate 130 are kept on the same level and leveled with one another. A second gate contact 160 is then formed to be connected to the first gate contact. The second gate contact 160 tends to contact the self-aligned contact structure 141 and a short circuit may occur between the self-aligned contact structure 141 and the gate 130 when there is an alignment shift in the process of forming the second gate contact 160 because the spacing between the gates 130 becomes smaller. Therefore, the process window is a problem to be improved.

Semiconductor structure and manufacturing method thereof


The present invention generally relates to a process for preparing alkoxylated alkylamines and/or alkyl ether amines. The process consists of two stages and utilizes a catalyst with a multiple-charge counterion. The alkoxylated alkylamines and alkoxylated alkyl ether amines prepared by the process possess the peaked ethoxylation distribution and contain less hazardous by-product.

Alkoxylated alkylamines and alkyl ether amines, particularly ethoxylated alkyl-amines and ethoxylated alkyl ether amines, have many applications in industry. They can be usefully employed as adjuvants in cleaning formulations, textile processing aids, dye transfer inhibitors, acid thickeners, detergent boosters, degreasers, anti-static agents, and the like.
Alkoxylated alkylamines and alkoxylated alkyl ether amines are materials possessing the following general structure (I):
wherein R is selected from a linear or branched, saturated or non-saturated alkyl group containing 8-22 carbon atoms or a group of the formula:R—O-(A)a-(B)b-(C)c,wherein A and B are alkylene oxide groups containing 2-4 carbon atoms, C is an alkylene group containing 3-4 carbon atoms, a, b each vary from 0-5, c is 1, X, Y, Z are alkylene oxide groups containing 2-4 carbon atoms, x is 1, and y varies from 1-15.
As illustrated by general formula (I), the alkoxylated alkylamines/alkoxylated alkyl ether amines possess a surfactant structure which is composed of the lipophilic groups (R) and the hydrophilic groups (polyalkylene oxide). In their designed applications, the performance of alkoxylated alkylamines and alkoxylated alkyl ether amines is dependent on a balance between the lipophilicity and the hydrophilicity provided by these groups.
Even when the lipophilicity-hydrophilicity balance does exist, the performance of the alkoxylated alkylamines/alkoxylated alkyl ether amines is not necessarily optimal. Traditionally, these materials are prepared from the base-catalyzed alkoxylation of the corresponding alkylamines/alkyl ether amines. Such an alkoxylation reaction is actually the polymerization reaction of alkylene oxide, including the characteristic propagation and chain transfer steps of the polymerization process. For this reason, the resulting alkoxylated alkylaminelalkyl ether amine is not a pure compound, but a mixture of many homologs.
As an example, FIG. 1 illustrates the homolog distribution of ethoxylated tallow amine prepared from the regular (hydroxide-catalyzed) ethoxylation of tallow amine with 5 moles of ethylene oxide. As shown in FIG. 1, the resulting ethoxylated product is not a single compound containing five (CH2CH2O) units as the general structure (structure I, with 2x+2y=5) may suggest. Instead, the product is a mixture of several homologs whose total of ethylene oxide units varies from 2 to 10. Among these homologs, only those in the middle of the distribution range (3EO-5EO) have the proper liphophilic-hydrophilic balance and, therefore, are preferred. Homologs with a shorter EO chain length (<3EO) or a longer EO chain length (>5EO) are not desirable, since they are either too lipophilic or too hydrophilic for the applications utilizing this product. Therefore, it is advantageous to develop an alkoxylation process that results in alkoxylated products with peaked distribution.
As covered in the prior art, an ethoxylation process offering peaked distribution has been developed; the ethoxylated alkylamines/alkyl ether amines having peaked distribution were successfully prepared by ethoxylation of the starting alkylamine catalyzed by a Lewis acid. However, hazardous property of the catalyst, lower reaction rate, degradation of the product colour, and formation of by-products have seriously limited the utilization and usefulness of this acid-catalyzed ethoxylation process and adversely affect the properties and the attractiveness of the ethoxylated products.
Accordingly, it is an object of the present invention to develop a process for the preparation of alkoxylated ethoxylated alkylamines and alkyl ether amines, particularly ethoxylated alkylamine and ethoxylated alkyl ether amine with peaked distribution having greatly minimized drawbacks compared to those associated with the acid-catalyzed process.

Process for preparation of alkoxylated alkylamines/alkyl ether amines with peaked distribution


A method for winding coils on a Y-connection armature for miniature motors, the motor typically including an armature iron core of a multi-pole construction, a commutator and a common terminal plate. Each of the commutator and the common terminal plate are disposed in a mutually insulated state on an insulating cylinder fixedly fitted to an armature shaft. A plurality of coils are wound on the armature iron core. Lead wires of the coils are connected to tongues of the commutator and the common terminal plate. Ends of the lead wires wound on the coils, other than the last coil, are extended across a predetermined commutator tongue and a tongue of the common terminal plate adjacent to the commutator tongue without being cut. The lead wire is connected to the tongues of the commutator tongue and the common terminal plate. Subsequently, the lead wire which is disposed across the commutator tongue and the common terminal plate tongue is cut.

This invention relates generally to a method for winding coils on a Y-connection armature for miniature motors, and more particularly to a method for winding coils on a Y-connection armature for miniature motors, which leads itself to simplification of the process for winding coils on a Y-connection armature and improvement of production efficiency.
FIG. 1 is a longitudinal sectional view illustrating the essential part of a miniature motor to which this invention is applied. In FIG. 1, reference numeral 21 refers to a motor housing, made of a magnetic material, such as mild steel, formed into a deep cup shape, a field magnet 22 is fixedly fitted to the inner circumferential surface of the motor housing 21. Numeral 23 refers to an end plate, fitted to an open end of the motor housing 21. Numeral 24 refers to an armature comprising an armature iron core 2, a commutator 5, and an armature shaft 1 fixedly fitted to the axial center thereof. Numerals 25 and 26 refer to bearings provided on the motor housing 21 and the end plate 23 to rotatably support the armature shaft 1. Numeral 27 refers to a terminal provided on the end plate 23. Numeral 28 refers to a brush electrically connected to the terminal 27, and formed in such a manner as to make sliding contact with the commutator 5.
With this construction, as electric current is fed from the terminal 27 to the armature via the brushes 28 and the commutator 5, the armature 24 disposed in a magnetic field formed by the field magnet 22 fixedly fitted to the inner circumferential surface of the motor housing 21 is caused to rotate.
FIGS. 2 and 3 are a side view and an enlarged longitudinal sectional side view illustrating the armature shown in FIG. 1. In FIGS. 2 and 3, numeral 2 refers to an armature iron core comprising three armature poles 7 and an armature shaft fixedly fitted to the axial center thereof; numeral 4 to an insulating cylinder fixedly fitted to an end of the armature shaft 1; numeral 5 to a commutator having three tongues 6 on the outer circumferential surface thereof and fixedly fitted to the outer circumferential surface of the insulating cylinder 4; numeral 10 to a common terminal plate having three tongues 11 on the outer circumferential surface thereof and fixedly fitted to the outer circumferential surface of the insulating cylinder 4 via an insulating ring-shaped member 12. The tongues 6 and 11 should preferably be disposed at essentially the same circumferential and axial positions.
Numeral 9 refers to a coil wound in a slot 3 formed on the armature iron core 2. An end of a lead wire 8 is connected to the tongue 6 of the commutator 5 and the other end thereof is connected to the tongue 11 of the common terminal plate 10 to form a Y-connection armature.
FIG. 4 is a development of assistance in explaining the conventional method for winding coils on a Y-connection armature. Like parts are indicated by like numerals in FIGS. 2 and 3. In FIG. 4, 71, 72 and 73 refer to armature poles disposed at 120-degree intervals with each other to form an armature iron core 2 in FIGS. 2 and 3. Numerals 61, 62 and 63 refer to tongues, representing the positions at which the tongues 6 of the armature 5 in FIGS. 2 and 3 are disposed. Numerals 111, 112 and 113 refer to tongues, representing the positions at which the tongues 11 provided on the common terminal plate 10 in FIGS. 2 and 3 are disposed. The tongues 61-63, and 111-113 are disposed at 120-degree intervals with each other, as in the case of the armature poles 71-73.
With the above-mentioned construction, a conventional method for winding coils on the Y-connection armature will be described. A first coil 91 is wound by connecting a trailing end of the lead wire 8 to the first tongue 61, then winding the lead wire 8 on the first armature pole 71 to form the first coil 91, and connecting the trailing end of the lead wire 8 to the first tongue 111 of the common terminal plate 10. After the terminal wire 8 is connected to the tongues 61 and 111 the lead wire 8 is subjected to the wire-end termination (a wire end termination procedure). Although only one turn of the first coil 91 is shown in FIG. 4 for simplicity, the coil 91 has a predetermined number of turns. This holds true with the second and third coils 92 and 93.
When winding the second and third coils 92 and 93, ends of the lead wires 8 are wound on the second and third armature poles 72 and 73 to form the second and third coils 92 and 93, and the other ends, that is, the trailing ends of the lead wires 8 are connected to the second and third tongues 112 and 113 of the common terminal plate 10.
In the conventional method for winding coils on a Y-connection armature as described above, the wire-end termination treatment has to be performed on the leading and trailing ends of the lead wire 8 every time one coil is formed.
That is, two wire-end terminations are needed for one coil. Consequently, 2N times of wire-end terminations are needed for N pieces of coils wound on a Y-connection armature.
Since the conventional method for winding coils on a Y-connection armature requires multiple wire-end terminations, as described above, coil winding is time consuming, requires complex winding operations, leading to lower production efficiency. This also results in increased motor cost.

Method for winding coils on a Y-connection armature for miniature motors


A flat pack gyroscope fabricated of a number of discrete flat layers, which, when assembled together, accomplish a version of a single degree of freedom, spinning wheel gyroscope.

Inertial guidance requires gyroscopes and accelerometers to measure the heading and linear motion of a vehicle. Spinning wheel gyroscopes have fallen out of favor in the last two decades relative to novel non-moving parts approaches represented by optical gyroscopes. With the recent development of MEMS (MicroElectroMechanical Systems) technologies, mechanical gyroscopes are again under consideration. The primary driver is that optical devices (Ring Laser Gyroscopes and Fiber-Optic Gyros) are large and do not lend themselves to automated fabrication. The result is that the manufacture of optical gyroscopes requires a large infrastructure and costs are high. The attraction of the MEMS-based microgyros is that they are small, can be integrated with the supporting electronics and can be batch-fabricated for low cost. The result is a great reduction in size, cost and power consumption. However, MEMS gyroscopes are microscopic in size which limits their performance. In addition, they are based primarily on oscillatory motions (Coriolis Effect) for generating angular momentum and for detecting rotational motion.
The Millimachined Flat-Pack Gyroscopes described here combine traditional spinning wheel concepts, that are well-understood, with MEMS technologies extended to larger dimensions to obtain higher performance capability yet retain the cost advantages of batch-processability. The approach is to reduce the conventional three dimensional single-degree-of-freedom design to a planar configuration which can be reduced to a multiple layer set. Each layer is batch-fabricated and the complete gyro is formed by stacking the layers. The electronics can be integrated into each layer as required or can be part of separate layers.
Millimachining is the design and fabrication of instruments and devices based on multi-layers. The functionality of the device is reduced to components which are made up of subcomponents. The subcomponents are located within a layer and the assembly of the layers forms the components and therefore the device. Millimachined devices are assembled by the pure stacking of the layers. The gyro has been converted from a three dimensional entity to a planar configuration which could be reduced to a set of layers. The layers are then fabricatable by modern planar technologies which are batch processable much like the Integrated Circuits.

Milli Sensor Systems and Actuators, Inc.


Metal foil provided with an electrically resistive layer, characterized in that an alloy (in particular, a NiCrAlSi alloy) resistive layer containing 1 to 6 mass % of Si is formed on the metal foil controlled to have a ten-point average roughness Rz, which was measured by an optical method, of 4.0 to 6.0 μm, and the variation in the resistance value of the electrically resistive layer is within ±10%. Provided is a copper foil that allows embedding of a resistive material in a board by further forming an electrically resistive layer on the copper foil, and further allows improving the adhesiveness and suppressing the variation in resistance value within a certain range. As needed, metal foil provided in advance with a copper-zinc alloy layer formed on the surface thereof and a stabilizing layer composed of at least one component selected from zinc oxide, chromium oxide, and nickel oxide formed on the copper-zinc alloy layer is used.

The present invention relates to a metal foil provided with an electrically resistive layer having excellent adhesiveness, high peel strength, and a low variation in resistance value, and relates to a printed circuit board comprising the metal foil.
Copper foil is generally used as a wiring material of printed circuit boards. The copper foil is classified based on the production process into electrolytic copper foil and rolled copper foil. The thickness of copper foil can be arbitrarily controlled from very thin copper foil of 5 μm to thick copper foil of about 140 μm.
The copper foil is bonded to a substrate of a resin such as an epoxy resin or a polyimide resin and is used in a printed circuit board. The copper foil is required to guarantee sufficient strength of adhesiveness to a resin serving as the substrate. Accordingly, in many cases of using electrolytic copper foil, the rough surface, a so-called mat surface, generally formed during production of the foil is further roughened and is then used. Rolled copper foil is also used similarly after surface-roughening treatment in many cases.
Recently, it is proposed to further form a thin-film layer of an electrically resistive material on copper foil serving as a wiring material (see Patent Documents 1 and 2). An electronic circuit board must comprise an electrically resistive element, and the use of copper foil provided with a resistive layer allows formation of the electrically resistive element merely by exposing the electrically resistive layer provided to the copper foil with an etching solution such as a cupric chloride solution.
Consequently, the limited surface area of the board can be effectively used by embedding the resistance in the board, compared with conventional methods of surface-mounting chip resistive elements on boards by soldering.
In addition, restriction on design is reduced by forming the resistive element inside a multilayer board, and the circuit length can be shortened to allow improvements in electrical characteristics. Accordingly, the use of copper foil having a resistive layer makes soldering unnecessary or highly reduces soldering and allows a reduction in weight and an improvement in reliability. Thus, a board having an electrically resistive layer embedded therein has many advantages.
The copper foil used as a base for resistive components is subjected to a surface treatment for further forming a resistive layer thereon. The copper foil differs from one for general printed board wiring, but is the same in the point of securing the adhesive strength to a resin by roughening.
A resin is further bonded on the resistive layer. Accordingly, in evaluation of the adhesive strength of a resistive material, it is necessary to investigate both the strength between the copper foil and the resistive layer and the strength between the resistive layer and the resin. For example, in peel strength evaluation, peeling occurs from the interface with a weaker strength.
In any case, a larger surface roughness provides a higher adhesive strength. The adhesive strength is thought to be affected by surface roughness and other factors such as surface chemical species (elemental species).
Continual improvement of the performance is required in printed circuit boards. Simultaneously, due to formation of finer resistance circuits and a demand for improvement in high-frequency characteristics, a reduction in surface roughness of resistive components is required. In order to achieve such requirements, it is necessary to increase the adhesive strength without relying on surface roughness.
However, it has not been exactly comprehended whether the surface roughness of copper foil affects an electrically resistive layer; what degree of surface roughness can maintain the characteristics of an electrically resistive layer; and what means can be employed for maintaining peel strength between an electrically resistive layer and a resin even when the adhesive strength decreases by reducing the surface roughness.
Accordingly, in conventional metal foil having an electrically resistive layer, a vague process of increasing the roughness of the surface of a copper foil is employed for enhancing the peel strength, and the above-mentioned problems have not been solved.
The present invention is an improvement of the invention of Patent Document 3 filed before by the present applicant. The invention described in Patent Document 3 is all effective and can be applied to the present invention.    Patent Document 1: Japanese Patent No. 3311338    Patent Document 2: Japanese Patent No. 3452557    Patent Document 3: Japanese Patent Application No. 2007-295117

Metal foil provided with electrically resistive layer, and board for printed circuit using said metal foil


A method and an apparatus for heating fluid with a gas heater and distilling fluid with the pilot light of the gas heater are disclosed. The apparatus for heating fluid and distilling fluid includes a main tank for containing fluid to be heated, a heater, adapted to have a pilot light, for heating the fluid in said main tank and an evaporator tank for vaporizing fluid received therein with heat from the pilot light. The method of heating fluid and distilling fluid includes heating a first volume of fluid with a heater having a pilot light and heating a second volume of fluid with the pilot light. A second apparatus for heating fluid and distilling fluid includes a main tank for containing fluid to be heated, a condensing tank adapted to pass fluid to said main tank, an evaporator tank for vaporizing fluid received therein, a condensing coil, disposed in said condensing tank, for exchanging heat between fluid vaporized by said evaporator tank and fluid in said condensing tank, a distillate tank adapted to receive condensed fluid from said condensing coil and an electric filament for heating fluid in said evaporator tank when a level in said distillate tank equals or exceeds a predetermined level.

The present invention is directed to a method and device for heating water, e.g., for household use, and for concurrently providing distilled water, e.g., for drinking (a thermostil). In the device, the energy used to distill water is then used to heat water in, say, a water heater, thus providing a very economical technique for obtaining clean drinking water. Currently, the cost of distilled water for drinking purposes or other forms of human consumption is uneconomical.
Some techniques or apparatuses have been proposed for economical drinking water distillation. One apparatus includes a water heater and distiller apparatus in which condensing steam in the distilling portion of the apparatus gives up its latent heat to water which is being heated in the water heating portion of the apparatus. However, the devices promote the use of separate or auxiliary heating elements and controlling energizing thereof based on an amount of fluid in a boiler, rather than exploiting the constant source of energy provided by a pilot light and controlling the amount of fluid to be evaporated thereby according to the amount of fluid in the boiler or amount of fluid recovered in a distillate tank. See, for example, U.S. Pat. No. 4,690,102, issued Sep. 1, 1987, to G. Sundquist, for Water Heater and Distiller Apparatus and U.S. Pat. No. 5,304,286, issued Apr. 19, 1994, to D. G. Palmer, entitled Water Supply System.
Another device includes a feed water intake which provides water in excess of the distilled water output, a heater controlling the quantity of water boiled, a waste water exit port to remove accumulated water above a certain level, a distilled water exit port in the vapor space, a condensing device to transfer the heat of condensation to a hot water tank and a waste water heat exchange device to transfer heat from a waste water to the hot water tank. See, for example, U.S. Pat. No. 4,601,789, issued Jul. 22, 1986, to J. G. Bjorklund entitled Water Purification Apparatus.
What are needed, and not taught or suggested in the art, are an apparatus for and a method of heating fluid with a gas heater and distilling fluid with the pilot light of the gas heater, and an apparatus for heating fluid with a gas heater and distilling fluid with an electric filament.

Apparatus for and method of heating fluid and distilling fluid


Method for correcting aberrations of an optical system and solving the problem of tolerance buildup. The method posits a desired specification limit for each of at least one optical characteristic of an optical element, and requires embossing at least a portion of a surface of the optical element for bringing the or each optical characteristic within its corresponding specification limit.

An optical system may comprise a single element, for example, a lens, a mirror, or a prism, or a combination of such optical elements, arranged for obtaining a combined optical characteristic. A combined optical characteristic, in turn, references a notion of describing a deviation from a nominal specification of a wavefront phase of an output radiation of the optical element, when the optical system is excited by a specified input radiation source.

Method for addressing wavefront aberrations in an optical system

International Business Machines Corporation


The device of the invention has a supporting body detachably fixed to a machine spindle, a head element detachably fixed to the supporting body, and at least one slide which can be moved substantially at right angles to the axis of rotation of the head element and which carries a tool or tool carrier. The radial motion of the slide is produced by the action of an axially moving actuator rod and gear means. In addition, there is in the supporting body a coolant channel for hydraulic fluid. The inlet end of the channel is connected to an opening in the spindle and the outlet opens out in the head element. For the operation of the slide, the supporting body has two cylindrical bores disposed coaxial to the axis of rotation and a certain distance apart and in which two rigidly linked pistons are located which can be connected to the actuator rod. In the first of the two cylinder, one side of the piston is acted on by hydraulic fluid from the coolant channel, the other side of the piston being acted on by atmospheric air. A return spring acts against the force exerted by the hydraulic fluid on the piston assembly. The second cylinder is connected up on both sides of the piston to a closed hydraulic circuit which includes a non-return valve which opens in the return direction and closes in the direction of the slide motion, plus a flow-control valve for fluid-feed and fluid-return control.

Facing heads are primarily used for facing of workpiece surfaces to a high surface quality and for cutting during internal and external machining. In addition, there are facing heads as they are needed for example for the valve machining industry or spherical-turning heads for the axle or armature industry. Replacement attachment tools broaden the field of use of a facing head.
In a known device for holding and operating a facing head of the above-disclosed type (DE-C 2 608 930), the adjusting mechanism includes an actuator rod arranged coaxially movably with respect to the axis of rotation of the supporting body on helical tooth systems arranged on two diametrically opposite sides, the teeth which cross, however, in relationship to the direction of movement of the actuator rod have the same angle. Each of two serrated slats arranged symmetrically with respect to the actuator rod are provided on the slide and on a counterweight of the slide, which serrated slats mate with the helical tooth system on the actuator rod. The teeth on the serrated slats of the slide extend thereby in opposite direction of the ones of the serrated slats on the counterweight. In the place of the counterweight, it is also possible to provide a second slide movable in an opposite direction to the first slide. A cross-feed mechanism extending centrally through the machine spindle is needed to operate the actuator rod. The cross-feed mechanism has been constructed especially for this purpose and can be operated from the side of the tool. On the other hand, the center area of the machine spindle is occupied with a feed device for the tool in machining centers with an automatic tool replacement capability so that an additional cross-feed mechanism cannot easily be stored there. On the other hand, it would be of a great advantage, in the interest of a complete machining of workpieces in one setting, when facing heads could also be inserted into machining centers.
It is hereby conducive to use the fluid coolant existing in each machining center and circulated with a high pressure of at least 15 bar as a drive means for the cross slide.
Based on this, the basic purpose of the invention is to provide a device for holding and operating a facing head of the above-disclosed type, with which, using the coolant in particular also existing in machining centers and circulating it under pressure, a slide adjustment is assured which is reliable, also at high speeds, and suitable for continuous operation.
To attain this purpose the following combination of characteristics is suggested according to the invention:
The supporting body has two spaced chambers arranged coaxially with respect to the axis of rotation, in which chambers are arranged two pistons rigidly coupled with one another and to the actuator rod; PA1 the first of the two chambers is loadable on the one piston side with pressure fluid from the coolant channel and on the other piston side with atmospheric air; PA1 a return spring acting against the force of the pressure fluid onto the piston arrangement is provided; PA1 the second chamber is connected on both sides of the piston to a closed hydraulic circuit which contains a check valve closing in machining direction of the slide movement and opening in return direction, and a flow-control valve. PA1 Center of gravity shift of the moved masses in various stroke positions of the slide; PA1 variable speeds and thus variable centrifugal forces acting on the slide; PA1 variable load during the machining operation based on different clamping cross sections; PA1 pressure variations in the coolant system.
The division into two separate hydraulic circulating systems makes it possible that in the open coolant circulating system also more or less contaminated coolant both for the cross-slide drive and also for the cooling and chip removal in the machining area can be utilized, and that the control of the feed and return speed, for which control is important, uncontaminated fluid be used, can be carried out in a closed hydraulic circuit. Since the centrifugal forces, depending on the speed of the facing head in the slide area, must be overcome by the operating device, the slide feed must be adjusted by adaptation to the respective machining tasks from case to case through the flow-control valve in the closed hydraulic circuit. The flow-control valve contains for this purpose advantageously an externally adjustable adjusting throttle for adjusting the volume flow within the closed hydraulic circuit. It must thereby be considered that significant pressure variations can result in the hydraulic circuit, for example for the following reasons:
In order to maintain the feed speed constant independently from pressure variations, the flow-control valve contains, according to a preferred embodiment of the invention, in addition a piston manometer with which the volume flow adjusted on the adjusting throttle can be very exactly controlled. The piston manometer has advantageously an operating piston controlling the cross section of an outflow opening of the flow-control valve, loaded with the difference pressure occurring at the adjusting throttle and a compression spring acting in opening direction of the outflow opening.
The spring acting onto the piston arrangement and the check valve in the closed hydraulic circuit permit, if necessary supported by the centrifugal force acting on the slide, an automatic quick return of the slide into its initial position.
In order to avoid a loss of fluid from the coolant channel of the supporting body during a tool exchange, an initially biassed check valve is arranged on the inlet side of the coolant channel. To moreover enable a transfer of coolant to the machining area of the facing head and to simultaneously avoid a fluid escape during the exchange of the head element, a check valve is arranged on the outlet side of the coolant channel in the supporting body, which check valve prevents a pressureless fluid discharge and contains an overflow throttle.
A leakage of hydraulic fluid from the closed hydraulic circuit is unavoidable during long periods of operation. The lost hydraulic fluid is slowly replaced with an air bubble without special measures, which because of the compressibility of air can cause initial control delays and when continuing can result in machining inexactnesses and breakdowns in operation. To avoid this, a preferred embodiment of the invention provides that the lost hydraulic fluid is constantly automatically replenished. A fluid reservoir is arranged in the supporting body for this purpose, through which reservoir hydraulic fluid is automatically added to the hydraulic circuit. The fluid reservoir is advantageously designed as a piston cylinder connected to the hydraulic circuit through a check valve and the piston of which acts under initial biassing against the fluid contained in the cylinder. The piston rests advantageously under the action of a spring against the fluid column. Furthermore, the piston can be arranged such that it acts, with the spindle rotating, under the action of the centrifugal force, onto the fluid column. The latter is the case when the piston rests radially outwardly against the fluid column, in particular when it is arranged radially within the fluid column in the fluid reservoir.
A fill-level control in the fluid reservoir and thus in the closed hydraulic circuit is realized according to the invention by rigidly connecting a pin to the piston, which pin upon a fluid reduction is moved radially outwardly in a pin hole. The pin hole can be arranged essentially radially in a locking lid of the fluid reservoir. When the control pin in the pin hole reaches the outer contour of the housing, then this is proof that fluid must be added. The fluid reservoir can for this purpose be filled from outside with hydraulic fluid through a closeable fill opening.
According to a further advantageous embodiment of the invention, the diameter of the first chamber is larger than the one of the chamber cylinder. The supporting body has advantageously a stepped bore concentric with respect to the axis of rotation, which bore is divided into two chambers by an intermediate lid connected to the bore step and having a fluid-tight, sealed piston-rod through opening therein. When the supporting body has a steep-angle taper shaft, then at least the second chamber and the return spring are arranged within the steep-angle taper shaft. The tool shaft can thereby have an annular recess opening toward the second chamber concentric with respect to the axis of rotation to receive the return spring in the form of a compression spring.
The piston in the second chamber has advantageously a further piston rod extending toward the spindle on a side remote from the first chamber, which piston rod sealingly, slidingly extends into a fluid chamber connectable to the connecting opening for the pressure fluid, which connecting opening is on the side of the spindle, so that the coolant channel leading to the first chamber and the head element can be extended axially through the piston rod and the further piston rod. In order to obtain a type of construction of the supporting body which is compact in axial direction, the supporting body has a bore concentric with respect to the axis of rotation with a cup-shaped piston therein which is open on one side to form the second chamber, and defining with a bottom wall thereof the first chamber within the bore, which wall has a piston-rod through opening therethrough. The bottom wall of the cup-shaped piston has advantageously an annular recess opening toward the first chamber to receive an annular shoulder axially projecting from the first piston and having at least one peripheral groove to receive a guide and/or seal ring therein.

Device for holding and operating a facing head

Komet Praezisionswerkzenge Robert Breuning GmbH


A lithographic apparatus is disclosed. The apparatus includes an illumination system for conditioning a beam of radiation, and an article support for supporting a substantially flat article to be placed in the beam of radiation. The article support includes a plurality of supporting protrusions for supporting the article, and at least one protective member located near a boundary of the supporting protrusions for protecting at least a boundary portion of the supporting protrusions during release of the article. The apparatus also includes a releasing device for releasing said article from said article support.

A lithographic apparatus is a machine that applies a desired pattern onto a target portion of a substrate. Lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In that circumstance, a patterning device, such as a mask, may be used to generate a circuit pattern corresponding to an individual layer of the IC, and this pattern can be imaged onto a target portion (e.g. including part of, one or several dies) on a substrate (e.g. a silicon wafer) that has a layer of radiation-sensitive material (resist). In general, a single substrate will contain a network of adjacent target portions that are successively exposed. Known lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion in one go, and so-called scanners, in which each target portion is irradiated by scanning the pattern through the projection beam in a given direction (the "scanning"-direction) while synchronously scanning the substrate parallel or anti-parallel to this direction.
In the conventional lithographic projection apparatus, during photolithographic processes, an article, such as a wafer or reticle, is clamped on an article support by a clamping force that may range from vacuum pressure forces, electrostatic forces, intermolecular binding forces or just the gravitational force. The article support defines a plane in the form of a plurality of protrusions defining an even flat surface on which the wafer or reticle is held. Tiny variations in the height of these protrusions are detrimental to image resolution, since a small deflection of the article from an ideal plane orientation may result in rotation of the wafer and a resulting overlay error due to this rotation. In addition, such height variations of the article support may result in height variation of the article that is supported thereby. During the lithographic process, such height variations may affect image resolution due to a limited focal distance of the projection system. Therefore, it is desirable to have an ideal flat article support.
European patent application EP0947884 describes a lithographic apparatus having a substrate holder in which protrusions are arranged to improve the flatness of the substrate. These protrusions have a general diameter of 0.5 mm and are located generally at a distance of 3 mm away from each other, thereby forming a bed of supporting members that support the substrate. Due to the relative large spaces in between the protrusions, any contamination that is present generally does not form an obstruction for the flatness of the substrate, since the contamination will be lying in between the protrusions and will not lift the substrate locally.
In the context of this application, the "article" may be any of the above-mentioned terms wafer, reticle, mask, or substrate, more specifically terms such as a substrate to be processed in manufacturing devices employing lithographic projection techniques; or a lithographic projection mask or mask blank in a lithographic projection apparatus, a mask handling apparatus such as mask inspection or cleaning apparatus, or a mask manufacturing apparatus or any other article or optical element that is clamped in the light path of the radiation system.
It has come to the attention of the inventors that this clamping force may cause problems when the article is released from the article support.
A common way to release the article from the article support is by stepping up a release force exerted by an ejection pin mechanism (e-pins), which engages at the article and provides a releasing force to disengage the article from the article support. The energy that is built up in the article during this stepping up is converted into displacement by subsequent release of the article surface from the article support surface. However, this built up energy may also cause damage to the article or article support. In general, by releasing the article from the article support, an uneven load distribution of the protrusions is obtained. In particular, the protrusions near a boundary are very much unevenly loaded and by slight rotations of the article and slip between the article and the supporting protrusions, the protrusions may wear and the article support will eventually loose its perfectly level plane of support due to tiny variations of the height and form of protrusions that are introduced during this release action.

Lithographic apparatus and device manufacturing method


The present invention provides a new and efficient process for the preparation of the dexmethylphenidate hydrochloride with high optical purity, the process comprising:                (a) reacting a solution of threo-N-Boc-ritalinic acid with (S)-1-phenylethylamine, separating precipitated solid salt of (R,R)-enriched N-Boc-ritalinic acid with (S)-1-phenylethylamnine from the reaction mixture and recrystallizing, reslurring and/or trituring of said salt;        (b) mixing the solid salt of (R,R)-N-Boc-ritalinic acid and (S)-1-phenylethylamine obtained in step (a) with aqueous acid and separating (R,R)-N-Boc-ritalinic acid from the mixture; and        (c) reacting the (R,R)-N-Boc-ritalinic acid prepared in step (b) with hydrogen chloride and methanol to give dexmethylphenidate hydrochloride with optical purity of at least 99% ee.

Dexmethylphenidate, also known as d-threo-methylphenidate, (R,R)-methylphenidate or (R,R)-α-phenyl-2-piperidineacetic acid methyl ester, having the formula:
is CNS (central nervous system) stimulant that is chemically and pharmacologically similar to the amphetamines. Dexmethylphenidate's CNS actions is milder than those of the amphetamines and have more noticeable effects on mental activities than on motor activities.
It has been reported by Sporzny (1961) that among racemic mixtures of threo and erythro diastereomers of methylphenidate, only threo-isomer displays stimulant properties. Dexmethylphenidate hydrochloride (i.e. the d-threo enantiomer of methylphenidate hydrochloride) has been reported to be 5 to 38 times more active than the corresponding (S,S)-methylphenidate hydrochloride (Prashad 2000).
A commercially available drug is sold under the name Focalin™ (Novartis) and it consists of dexmethylphenidate in the form of the hydrochloride salt. This product is orally administered and clinically used in the treatment of narcolepsy and as adjunctive treatment in children with attention deficit disorder (ADD) and attention-deficit hyperactivity disorder (ADHD).
A synthesis of dexmethylphenidate hydrochloride was firstly described in U.S. Pat. No. 2,838,519 and include resolution of erythro-α-phenyl-2-piperidineacetamide to obtain enantiopure (2R,2′S)-α-phenyl-2-piperidineacetamide, which was subjected to epimerization, hydrolysis, and esterification as shown in Scheme 1:

Related example of preparation of dexmethylphenidate from erythro-α-phenyl-2-piperidineacetamide was described in U.S. Pat. No. 5,936,091.
Preparation of dexmethylphenidate through optical resolution of threo-α-phenyl-2-piperidineacetamide was described in U.S. Pat. No. 5,965,734, as shown in Scheme 2:

Synthetic methods for the preparation of racemic mixture of threo- and erythro-α-phenyl-2-piperidineacetamides as raw materials for the preparation of dexmethylphenidate were described by Panizzon (1944) and Patric (1982) and in U.S. Pat. Nos. 2,507,631, 2,838,519, 2,957,880 and 5,936,091, and in WO 01/27070. These methods include using sodium amide as base in the nucleophilic substitution of chlorine in 2-chloropyridine with phenylacetonitrile followed by hydrolysis of the formed nitrile and reduction of a pyridine ring to a piperidine one by hydrogenation on PtO2 catalyst, as shown in Scheme 3:

Alternatively, 2-bromopyridine was used instead of 2-chloropyridine by Deutsch (1996).
In some other methods threo-methylphenidate was used as the raw material for the preparation of dexmethylphenidate. Threo-methylphenidate may be prepared by a several routes, inter alia by the following two processes:
i) by esterification of threo-ritalinic acid which may be prepared from erythro-enriched and threo-α-phenyl-2-piperidineacetamides as shown in Scheme 4:

ii) by cyclization of easily available 1-(phenylglyoxylyl)piperidine arenesulfonylhydrazone to (R*,R*)-enriched 7-phenyl-1-azabicyclo[4.2.0]octan-8-one and further converting the β-lactam to threo-methylphenidate hydrochloride, as described by Axten (1998), Corey (1965) and Earle (1969) and in WO 99/36403 and shown in Scheme 5:

The resolution of threo-methylphenidate to afford dexmethylphenidate was first reported by Patric (1987) which used (R)-(−)-binaphthyl-2,2′-diyl hydrogen phosphate as the resolving agent. Several new resolutions of threo-methylphenidate have been reported recently by Prashad (1999) and in U.S. Pat. Nos. 6,100,401, 6,121,453, 6,162,919 and 6,242,464 as described in Scheme 6:
wherein the chiral acid is one of the following: (R)-(−)-binaphthyl-2,2′-diyl hydrogen phosphate, (−)-menthoxyacetic acid, ditoluoyl-D-tartaric acid or dibenzoyl-D-tartaric acid.
Resolution of threo-methylphenidate may be also achieved by enzymatic hydrolysis methods as proposed by Prashad (1998) and in WO 98/25902. Such resolution is described in Scheme 7:

Resolution of threo-ritalinic acid hydrochloride with (S)-1-phenylethylamine give complex salt (R,R)-enriched threo-ritalinic acid.HCl.(S)-1-phenylethylamine with 77% ee optical purity of ritalinic acid (U.S. Ser. No. 2002/0019535), Scheme 8:

Process for the preparation of dexmethylphenidate hydrochloride

Abstract: The present invention further provides salt of (R,R)-N-Boc-ritalinic acid with (S)-1-phenylethylamine as new intermediate in the preparation of dexmethylphenidate hydrochloride.


A power unit of a vehicle, which includes an internal combustion engine and a transmission, is provided which is configured to quickly return lubricating oil fed to the transmission to an oil storage portion of the power unit case. The transmission includes a gear train housed in a gear chamber, the gear train executing power transmission among an input shaft, an intermediate shaft and an output shaft. The input shaft and the output shaft are arranged such that a line connecting their respective shaft centers extends almost horizontally above a communicating port which permits return oil flow between segregated portions of the power unit case. In addition, the intermediate shaft is disposed above and between the input shaft and the output shaft.

1. Field of the Invention
The present invention relates to a vehicle power unit, the power unit including an internal combustion engine and a transmission, the transmission modifying the rotational speed of the engine and transmitting the rotational driving force of the engine to vehicle wheels.
2. Description of the Background Art
In a known a vehicle power unit, which includes an internal combustion engine and a transmission, the transmission is configured to include input and output shafts disposed parallel to each other, and to further include a plurality of gear trains arranged between the input and output shafts. Such a power unit is disclosed, for example, in Japanese Patent Laid-Open No. 2002-227939. In the known vehicle power unit, lubricating oil is fed to sliding portions such as shafts and gears in order to stably operate an internal combustion engine and a power transmission device. A power unit case, which provides a housing for the internal combustion engine and the power transmission device, is formed with an oil storage portion adapted to collect the lubricating oil, which is fed under pressure to various portions by a feed pump.
The power transmission device of Japanese Patent Laid-Open No. 2002-227939 transmits rotation of a crankshaft to a main shaft, and the rotation of the main shaft to a countershaft in order to set a forward stage, or to an idle shaft for setting a reverse stage. Thus, the rotation of either the counter shaft or idle shaft is transmitted to an output shaft. These shafts are rotated and are provided with gears thereon; therefore, lubricating oil is fed to the shafts and to the gears. The lubricating oil fed to the shafts collects on the bottom of an inner space housed in a gear case housing the power transmission device.
However, the output shaft in the power transmission device of Japanese Patent Laid-Open No. 2002-227939 is disposed below a line connecting the respective shaft centers of the counter shaft and the idle shaft. Therefore, gearwheels carried on a shaft whose height from the oil storage portion is small are met with great stirring resistance, which may possibly lead to deterioration in power transmission efficiency.
In view of such a problem, an object of the present invention is to provide a power transmission device for a vehicle configured to quickly return lubricating oil which has been fed to the power transmission device to an oil storage portion.

Vehicle power unit with improved lubrication oil recovery structure


A device for adding a flavoring product to a liquid includes a tubular body having openings extending through a sidewall of the body to an interior cavity. A flavoring product is loaded into the interior cavity. At least one fin is coupled to the tubular body and extends outwardly from the sidewall. The device, with the flavoring product loaded therein, is inserted into a container and a liquid is added to the container. The openings in the tubular body are sized to admit the liquid into and out of the interior cavity to enable infusion of the flavoring product into the liquid and to discharge the flavored liquid. The fin is configured such that following insertion into the container, the fin is positioned to largely prevent the tubular body of the device from blocking the opening into the container and inhibiting discharge of the liquid.

A plethora of alcoholic and non-alcoholic beverages exists for the consumer to drink. Beer is considered to be the world's most widely consumed alcoholic beverage, and it is the third-most popular drink overall, after water and tea. The basic ingredients of beer are water, a starch source able to be converted to sugars, such as malted barley, a brewer's yeast to produce the fermentation, and a flavoring such as hops. Consumers and home brewers are becoming increasingly intrigued by expanding flavor pallet profiles of beer.

Device and method for adding flavoring to a liquid


A position measuring apparatus includes an imaging device and a controller, and is mounted on one or more mobile objects and configured to measure a position of a target. The imaging device is configured to acquire images of the target from a plurality of locations that are different from each other. The controller is configured to measure, on the basis of the images of the target, one or both of orientations of the target as viewed from the respective locations and distances to the target from the respective locations, correct one of the measured orientations of the target and the measured distances to the target to thereby reduce a difference between times at which the respective images are acquired at the respective locations, and calculate an estimated position of the target, on a basis of one of the corrected orientations of the target and the corrected distances to the target.

The technology relates to a position measuring method, a position measuring apparatus, and a position measuring system that measure a position of a movable object.
In general, radar has been used as a method that measures, from a mobile object, a position of a target such as a flying object. The radar, however, emits radio waves, making it possible for others to detect a position of the mobile object easily. An alternative method may be to measure a distance on the basis of a focus adjustment of an optical camera. Such a method, however, involves a large measurement error in a case where an object to be photographed is relatively distant, or in a case where an optical camera is used that has a large depth of field.
Japanese Unexamined Patent Application Publication (JP-A) No. 2002-188914 discloses a technique that measures target orientations from respective two different locations by utilizing a difference in position of a mobile object resulting from an elapse of time. The technique disclosed in JP-A No. 2002-188914 determines a position of a target on the basis of an intersection of the two orientations.
Japanese Patent (JP-B) No. 4328551 discloses a technique that measures a distance to a target by means of a stereo camera mounted on a body of an aircraft. The method disclosed in JP-B No. 4328551 allows for a measurement of a position of the target without involving emission of radio waves.

Position measuring method, position measuring apparatus, and position measuring system


A method of pretinning a guidewire core made of shape memory alloy and having an elongate axis, comprising: placing a ball of solder in a pocket in a soldering block; melting the ball of solder; holding a guidewire core over the ball of solder; lowering the guidewire core into the ball of solder; removing the guidewire from the ball of solder.

It is known in the art to form guidewires for placement in the human anatomy. Many guidewires are fabricated from a superelastic Nitinol (nickel titanium) alloy. In some known methods of guidewire fabrication and assembly, the distal end of the nitinol core is "pretinned" with a solder alloy to enable subsequent assembly by soldering a coil onto the distal end.
Such known methods may include a pretinning process which involves a heated crucible containing several pounds of molten solder and a cover layer of molten flux. The molten solder may be a mixture of tin and gold, and as a consequence the value of a solder station known in the art may be between $40,000 to $50,000. The flux may be a eutectic mixture of sodium hydroxide and potassium hydroxide. The distal end of each core wire is plunged or dipped into the crucible multiple times, resulting in a pretinned section approximately 5 cm long that is readily solderable at any point along that length using the type of flux typically used for stainless steel.
In some guidewire designs, the entire nitinol core wire is in the superelastic condition, having been previously cold worked via wire drawing then heat treated at about 500° C. to straighten the drawn wire and impart superelasticity. Because superelastic nitinol has already been heat treated at a higher temperature than will be encountered during the pretinning procedure, this pretinning method may affect straightness of the wire if the wire is bent while exposed to pretinning temperatures. That is, the bend will become permanent. (However, it is a characteristic of superelastic NiTi that has been previously cold worked prior to heat treatment, that its straightness will not be impacted where it is held straight while being heated in a pretinning process)
However, in other designs, the tip of the guidewire core may be treated, by various different means including by cold working, to remove the superelastic properties. This leaves the tip capable of being deformed permanently by the user. A design and method following such a process is disclosed in application Ser. No. 14/042,321 which is co-owned by the applicant company. It is incorporated herein in full, by reference. Thus, where the user requires a J tip, a micro-J tip, or other desired shape to facilitate threading the guidewire in a complex anatomy, such shape may be imparted to the tip manually before insertion into the patient. In the case of such guidewire core, the method of pretinning described above, wherein the distal end of each core wire is plunged into the crucible multiple times up to a depth of about 5 cm, causes significant distortion to occur in the cold worked section.
As further background, the need for pretinning nitinol core wires arises before they are soldered. Soldering fluxes that enable solder alloys to wet nitinol are commercially available so, in theory, pretinning before assembly should be unnecessary. However, certain alloys that are frequently used for their other beneficial characteristics, (for example, Indium Alloys' Flux #2 and Flux #3) volatilize when heated and leave considerable residue that can tenaciously mask areas where solder is intended to flow. Further, such residue can be challenging to remove, particularly when trapped within coils or other features having little clearance and poor line-of-sight inspectability.
In this respect, non-removed residue is highly undesirable because it can cause subsequent corrosion of the solder or substrate materials. For this reason, it is advantageous to pre-tin and completely remove all pre-tinning flux residue while it is exposed and readily visible, and then use an easier-to-remove flux when subsequently soldering the pre-tinned nitinol core wires into assemblies. For example, fluxes used for soldering stainless steels or precious metals are aqueous solutions containing zinc chloride and hydrochloric acid, and their residue does not exhibit a masking effect and is far easier to remove from coils and other low-clearance features.
Thus, there is in the art, a need for a method for pretinning guidewire cores made from superelastic alloys, which avoids the above problem. The present invention addresses these and other needs.

Method for selectively pretinning a guidewire core


A bioptical workstation includes plural image capture modules for capturing images of indicia along different fields of view. Each module includes an illuminator for illuminating the indicia with illumination light, a megapixel imager with a rolling shutter for sequentially capturing the return light, and a shutter element for passing the return light to its imager in an open state, and for blocking the return light from other modules from reaching its imager in an closed state. A controller prevents interference among the modules by controlling the shutter element to assume the open state only during a respective exposure time period during which its imager produces an electrical signal indicative of the indicia, and by controlling the shutter element to assume the closed state at all times other than the respective exposure time period to prevent capture of the return light from the other modules.

Flat bed laser readers, also known as horizontal slot scanners, have been used to electro-optically read one-dimensional bar code symbols, particularly of the Universal Product Code (UPC) type, at a point-of-transaction workstation in supermarkets, warehouse clubs, department stores, and other kinds of retailers for many years. As exemplified by U.S. Pat. No. 5,059,779; U.S. Pat. No. 5,124,539 and U.S. Pat. No. 5,200,599, a single, horizontal window is set flush with, and built into, a horizontal countertop of the workstation. Products to be purchased bear an identifying symbol and are typically slid across the horizontal window through which a multitude of scan lines is projected in a generally upwards direction. When at least one of the scan lines sweeps over a symbol associated with a product, the symbol is processed and read.
The multitude of scan lines is generated by a scan pattern generator which includes a laser for emitting a laser beam at a mirrored component mounted on a shaft for rotation by a motor about an axis. A plurality of stationary mirrors is arranged about the axis. As the mirrored component turns, the laser beam is successively reflected onto the stationary mirrors for reflection therefrom through the horizontal window as a scan pattern of the scan lines.
It is also known to provide a point-of-transaction workstation not only with a generally horizontal window, but also with an upright or generally vertical window that faces an operator at the workstation. The upright window is oriented generally perpendicularly to the horizontal window, or is slightly rearwardly or forwardly inclined. The laser scan pattern generator within this dual window or bioptical workstation also projects the multitude of scan lines in a generally outward direction through the upright window toward the operator. The generator for the upright window can be the same as, or different from, the generator for the horizontal window. The operator slides the products past either window, e.g., from right to left, or from left to right, in a "swipe" mode. Alternatively, the operator merely presents the symbol on the product to an approximate central region of either window in a "presentation" mode. The choice depends on operator preference or on the layout of the workstation.
Each product must be oriented by the operator with the symbol facing away from the operator and generally towards either window of the bioptical workstation. Hence, the operator cannot see exactly where the symbol is during scanning. In typical "blind-aiming" usage, it is not uncommon for the operator to repeatedly swipe or present a single symbol several times before the symbol is successfully read, thereby slowing down transaction processing and reducing productivity.
The blind-aiming of the symbol is made more difficult because the position and orientation of the symbol are variable. The symbol may be located either low or high, or right or left, on the product, or anywhere in between, or on any of six sides of a box-shaped product. The symbol may be oriented in a "picket fence" orientation in which the elongated parallel bars of the one-dimensional UPC symbol are vertical, or in a "ladder" orientation in which the symbol bars are horizontal, or at any orientation angle in between.
In such an environment, it is important that the laser scan lines located at, and projected from, either window provide a full coverage scan zone which extends down as close as possible to the countertop, and as high as possible above the countertop, and as wide as possible across the width of the countertop. The scan patterns projected into space in front of the windows grow rapidly in order to cover areas on products that are positioned not on the windows, but several inches therefrom. The scan zone must include scan lines oriented to read symbols positioned in any possible way across the entire volume of the scan zone.
As advantageous as these laser-based, point-of-transaction workstations have been in processing transactions involving products associated with one-dimensional symbols each having a row of bars and spaces spaced apart along one direction, the workstations cannot process stacked symbols, such as Code 49 which introduced the concept of vertically stacking a plurality of rows of bar and space patterns in a single symbol, as described in U.S. Pat. No. 4,794,239, or PDF417 which increased the amount of data that could be represented or stored on a given amount of surface area, as described in U.S. Pat. No. 5,304,786, or two-dimensional symbols.
Both one- and two-dimensional symbols, as well as stacked symbols, can also be read by employing solid-state imagers which have a one-dimensional array or a single row, or a two-dimensional array or multiple rows, of cells or photosensors that correspond to image elements or pixels in a field of view of the imager. Such an imager may include a one- or two-dimensional charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) device, as well as associated circuits for producing electronic signals corresponding to the one- or two-dimensional array of pixel information over the field of view.
It is therefore known to use a solid-state imager for capturing a monochrome image of a symbol as, for example, disclosed in U.S. Pat. No. 5,703,349. It is also known to use a solid-state imager with multiple buried channels for capturing a full color image of a target as, for example, disclosed in U.S. Pat. No. 4,613,895. It is common to provide a two-dimensional CCD with a 640×480 resolution commonly found in VGA monitors, although other resolution sizes are possible.
It is also known to install the solid-state imager, analogous to that conventionally used in a consumer digital camera, in a bioptical, point-of-transaction workstation, as disclosed in U.S. Pat. No. 7,191,947, in which the dual use of both the solid-state imager and the laser scan pattern generator in the same workstation is disclosed. It is possible to replace all of the laser scan pattern generators with solid-state imagers in order to improve reliability and to enable the reading of two-dimensional and stacked symbols, as well as other targets.
However, it was thought that an overall imager-based reader would require about ten to twelve imagers in order to read a symbol that could be positioned anywhere on all six sides of a product. To be successful in the marketplace, as disclosed in commonly-assigned U.S. patent application Ser. No. 11/823,818, filed Jun. 28, 2007, the entire contents of which are incorporated herein by reference thereto, an all imager-based reader must eliminate the need for so many imagers to bring the cost of all the imagers, as well as the cost of each imager, down to an acceptable level, and it must also match, or at least be comparable to, the working range, processing speed, productivity and performance of a laser-based reader. In the case of a bioptical workstation having dual windows, the all imager-based reader must use similar window sizes and must also be able to scan anywhere across the windows and over a comparable working range as that of a laser-based reader, so that operators can achieve the high scanning productivity they have come to expect without any need to learn a new scanning technique.
As advantageous as the all imager-based bioptic reader can be in reading symbols, as disclosed in commonly-assigned U.S. patent application Ser. No. 12/220,333, filed Jul. 23, 2008, the entire contents of which are incorporated herein by reference thereto, interference or crosstalk among the imagers can occur if any two imagers are simultaneously operative. Each imager includes an illuminator for illuminating the symbol with illumination light from one or more illumination light sources, e.g., light emitting diodes (LEDs). A controller is operative for controlling each illuminator to illuminate the symbol, and for controlling each imager to capture the illumination light returning from the symbol over an exposure time period to produce electrical signals indicative of the symbol being read. Each illuminator is only operative during the exposure time period. The illumination light is typically folded by field mirrors to be reflected and captured through the windows.
If the exposure time periods from any two imagers are concurrent, then interference or crosstalk among the illuminators can be caused by multiple internal reflections from the field mirrors within the reader. The illuminated image being captured by any one imager may be corrupted by light associated with another imager. Also, the possibility of uneven illumination could occur if more than one set of illumination LEDs is energized at the same time. In addition, the peak current consumption of the entire reader may be too high if more than one set of illumination LEDs are energized at the same time.
To prevent such concurrent exposure time periods from any two imagers, preferably each having a wide VGA (WVGA) resolution, e.g., 800×480, 848×480, or 854×480, wider than VGA, it is known to configure each imager with a global shutter. With a global/synchronous shutter, all rows in the array are reset and then exposed simultaneously for a specified exposure time period. The global shutter is synchronized with the illuminator. The global shutter exposes the entire imager simultaneously. An entire frame is exposed and begins gathering light. When the specified exposure time period has elapsed, the imager stops gathering light and turns its current exposure into an electronic image. At the start of an exposure, the entire imager starts gathering light. At the end of the exposure, the light-gathering circuitry is electronically turned off, and the contents of the imager are then read out and processed to generate an image.
Although WVGA imagers with global shutters can work in the all imager-based bioptic reader, mega-pixel (MP) imagers are preferred, because they provide a much higher resolution, as well as an enhanced capability of reading symbols of high density. MP imagers with global shutters are available, but at a prohibitively high cost, especially when multiple imagers are required in the reader. MP imagers with rolling shutters are available at a much lower cost, but a rolling shutter exposes different rows or portions of the imager at different points in time, "rolling" through the frame. Different portions of the imager become light-sensitive at different moments in time, and this process sequentially proceeds down or across the course of the full frame, until the entire imager is exposed. This rolling action, however, can cause undesirable exposure at each imager to illumination from other illumination light sources from the other imagers, thereby degrading the captured image by such crosstalk. Accordingly, it would be desirable to use MP imagers with rolling shutters, but without the drawback of imager crosstalk.

Electro-optical imaging reader having plural solid-state imagers with shutters to prevent concurrent exposure


The present invention is directed to a system for tracking a contact center operation. The system includes a tracking agent 232 operable to (a) receive a notification indicating a change in agent focus from a first work item to a second work item; (b) determine whether the first work item involves a communication medium different from the second work item; and (c) when the first work item involves a communication medium different from the second work item, cause termination of a timer with respect to the servicing of the first work item and initiation of a timer with respect to the servicing of the second work item. The first and second work items are concurrently assigned for servicing to the agent.

Contact centers, such as Automatic Call Distribution or ACD systems, are employed by many enterprises to service customer contacts. A typical contact center includes a switch and/or server to receive and route incoming packet-switched and/or circuit-switched contacts and one or more resources, such as human agents and automated resources (e.g., Interactive Voice Response (IVR) units), to service the incoming contacts. Contact centers distribute contacts, whether inbound or outbound, for servicing to any suitable resource according to predefined criteria. In many existing systems, the criteria for servicing the contact from the moment that the contact center becomes aware of the contact until the contact is connected to an agent are customer-specifiable (i.e., programmable by the operator of the contact center), via a capability called vectoring. Normally in present-day ACDs when the ACD system's controller detects that an agent has become available to handle a contact, the controller identifies all predefined contact-handling skills of the agent (usually in some order of priority) and delivers to the agent the highest-priority oldest contact that matches the agent's highest-priority skill. Generally, the only condition that results in a contact not being delivered to an available agent is that there are no contacts waiting to be handled.
An important factor in administering call distribution algorithms and rewarding agents based on performance is accurate tracking and reporting of agent performance. In monitoring agent performance, two areas are particularly troublesome. First, how should one track the previewing of work that is new or has been deferred while deciding what to do next? As will be appreciated, when an agent previews a work item, he or she is typically provided with a summary or condensed description of one or more work items (which can include, for example, contactor identity, nature or subject of the contact, arrival time, type of media, and intended recipient) and, based on the description, decides whether he or she is qualified or otherwise able to service the contact and/or prepares himself or herself to service the contact. Consideration must be given to performance when scrolling through a list of work items, like email, in a preview mode prior to selecting a work item. Second, how should one track work time when it appears that the agent is working on more than one thing simultaneously? For example, an agent is handling a first contact on a first communication medium (e.g., a live voice contact) for a first customer while at the same time handling a second contact on a second communication medium (e.g., an email or Web chat) for a second customer. More specifically, the agent does not have the first or second contact on hold while intermittently working on or wrapping up the other contact (completing the after call work). It is desirable to track accurately the agent's time for each work item. Inaccurate tracking can lead to nonsensical results, such as showing agents being present for more time than they are actually present and/or showing agent occupancy levels greater than 100%. Such erroneous results can propagate into significant errors in administering the call distribution algorithm. Moreover in some applications, the contact center may wish to discourage multi-tasking due to a concomitant decrease in the quality of service.
While tracking voice contacts is well established and accurate in the industry, the tracking of other channels or communication media (e.g., email, chat) is neither established nor accurate. For example, an agent using Avaya Inc.'s Interaction Center™ can read an entire email or web chat by previewing it and have that time counted as idle time or against another work item. It is only when the agent replies (because it requires explicit input) that accurate accounting for that email or web chat begins. Since it is impossible to know what work item an agent is thinking about without explicit agent input, multi-tasking tracking has not been done effectively. For example, the agent can be listening to a caller while at the same time concentrating on reading an email or web chat.


A data readout system with non-uniform resolution has a pick up head for reading data stored in an optical disc and generating an analog signal, a reference voltage unit for producing a plurality of reference voltage levels, wherein voltage differences between two adjacent reference voltage levels are not all the same, a plurality of comparators for comparing the reference voltage levels with the analog signal and generating comparison results, and an encoder for encoding the comparison results into a digital signal.

The invention relates to an analog-to-digital converter, and more particularly, to an analog-to-digital converter used in a data readout system.
In modern circuit design, high speed analog-to-digital converter is important because of the need for transferring massive information from analog signals into digital signals. A Flash ADC is commonly used for converting analog signals into digital signals at a high speed. The high speed of a Flash ADC is achieved by parallel operation. Traditionally, 2n−1 comparators are used in an n-bit Flash AD converter. The 2n−1 comparators operate simultaneously and then the comparison results are encoded into an n-bit digital output. However, comparators occupy a large area in a Flash AD converter. The higher the resolution requirement is, the larger the area would be. For a data readout system, such as an optical drive, a great amount of data needs to be read from an optical disc and transferred into digital formats very fast and reliable. More comparators could increase resolution and accuracy, but suffer from large chip area and high cost. Thus, there is a need for a new analog-to-digital circuit with high accuracy, high speed, but with smaller area and lower cost.

Data readout system having non-uniform ADC resolution and method thereof