The cell has a wound electrode assembly 50 including a positive electrode 64 and a negative electrode 84 that are wound with a separator 90 interposed therebetween, and a liquid electrolyte, wherein the negative electrode includes an elongated negative electrode current collector 82, and a negative electrode mixture layer 88 that is formed on the negative electrode current collector and contains at least a graphite material 85. The graphite material in the negative electrode mixture layer is arranged such that the (002) plane 85A of at least 50 mass % of the graphite material is perpendicular to the surface of the negative electrode current collector and parallel to the longitudinal direction of the elongated negative electrode current collector.

Lithium-ion secondary cells include a positive electrode, a negative electrode and a liquid electrolyte which intermediates the electrodes and are charged and discharged by transfer of lithium ions between the positive and negative electrodes via the liquid electrolyte containing an electrolyte component such as a lithium salt. Typical negative electrodes in this type of lithium-ion secondary cells contain a negative electrode active material which can reversibly store and release lithium ions. The negative electrode active material is mainly various carbon materials such as graphite materials. Graphite has a laminar crystalline structure and allows charge and discharge by storing lithium ions to interlayers and releasing lithium ions from interlayers.
When a current collector is coated with a composition prepared in a paste-like form containing graphite as a negative electrode active material (the paste composition includes a slurry composition and an ink composition; hereinafter the paste composition is merely referred to as "composition") to form a negative electrode, graphite tends to be arranged such that the layers of graphite ((002) planes) are parallel to the surface (plane having a broader width) of the current collector. Therefore edge parts (edges of multiple layers) of graphite may be arranged approximately parallel to the current collector, and storaging lithium ions to interlayers and releasing lithium ions from interlayers may not be smoothly carried out during charge and discharge. Patent Literature 1 may be mentioned as the conventional art that sought to address such a problem. Patent Literature 1 discloses a technique for arranging layers of graphite so as to be perpendicular to a current collector by applying a magnetic field to a composition. In addition, Patent Literature 2 may be mentioned as the conventional art relating to the negative electrode of lithium-ion secondary cells.

Lithium-ion secondary cell and method for manufacturing same


Provided are an H5 avian influenza vaccine strain which differentiates infected from vaccinated animals, a preparation method therefor, and an application. The vaccine strain uses an NA protein of influenza B as a label, and has application value and public health significance for the prevention, control and decontamination of H5 avian influenza.

Avian influenza virus belongs to the genus of influenza virus, the family of Orthomyxoviridae. Influenza viruses are classified into types A, B, and C in terms of antigenic diversity, wherein influenza A viruses have a broad species tropism (including avian, human, swine, etc.), with a strong pathogenicity and huge damages. Influenza B viruses are primarily limited to the human population, although rare infections of seals have been documented, with a relatively low pathogenicity. Influenza C viruses are only found in human and swine. The genomes of influenza A and B can be divided into 8 gene segments in total: PB2, PB1, PA, NP, HA, NA, M, and NS. Once being infected, hosts may generate a large amount of antibodies to HA, NA, M1 and NP proteins, wherein HA may induce major neutralizing antibodies directly. It is found in previous researches that the four major antibodies against HA, NA, M1 and NP induced by viruses of types A and B have no serological cross-reactivity. The antigenic diversity of the HA and NA proteins of the influenza virus is used to classify influenza viruses into different subtypes (HnNn), wherein there are 18 subtypes for HA and 11 subtypes for NA, which may produce 198 (18×11) subtypes theoretically, however, there are only a few advantage subtypes in nature actually (e.g., H5N1, H7N9, H9N2, etc.). The sequence homologies among different subtypes of HA proteins are between 40%-80% (Air G M. Proceedings of the National Academy of Sciences of the United States of America, 1981, 78(12):7639. Nobusawa E, et al. Virology, 1991, 182(2):475-485). There are no subtypes for influenza B, with high similarities between each virus strain gene. According to the antigenic variant, influenza B viruses are currently divided into only two lineages, Victoria group (named following B/Victoria/2/1987) and Yamagata group (named following B/Yamagata/16/1988) respectively. There are almost all subtypes of influenza A in avian species, playing important roles in the storage and evolution of the virus. The global epidemic of avian influenza has caused huge economic losses to the poultry industry, the cases of human infections with avian influenza are increasing gradually with the gradual adaptation of avian influenza viruses to human. Compared with seasonal human influenza, human infections with avian influenza are characterized by severe morbidity and high mortality, greatly threatening the public health safety. In numerous subtypes of avian influenza, H5 is extremely hazardous, causing huge economic losses. Highly pathogenic H5 avian influenza may result in 100% death of the poultry in a few days, and may infect human directly. Infections in human are serious in symptoms and high in mortalities. The thoroughly decontamination of avian influenza in the farms is the most effective means for eliminating the risks to the food safety and the public health.
At present, vaccination is one of the most effective methods for preventing and controlling avian influenza. The vaccine strains constructed with the internal gene of the chick-embryo highly adaptable strain PR8 as the background with the external genes (HA, NA) which are substituted for the epidemic strains are safe, effective and inexpensive, being applied most extensively in China, and playing important roles in preventing and controlling of avian influenza. However, this kind of whole virus inactivated vaccine cannot serologically differentiate infected from vaccinated animals, causing a great obstacle in the monitoring and decontamination of avian influenza virus. In the life cycle of virus, the HA protein attaches the virus to the cell surface by binding to sialic-acid-containing receptors and promotes viral penetration by mediating fusion of the endosomal and viral membranes, and the NA protein functions as a homotetramer, facilitating the mobility of virions by removing sialic acid residues from viral glycoproteins and infected cells during both entry and release from cells. Therefore, a balance of competent HA and NA (the matching of HA-NA) activities appears critical and may directly affect the replication capacities and growth properties of influenza viruses (Mitnaul L J, Matrosovich M N, Castrucci M R, et al. Balanced Hemagglutinin and Neuraminidase Activities Are Critical for Efficient Replication of Influenza A Virus[J]. Journal of Virology, 2000, 74(13):6015-20.). Therefore, selection of viruses with HA and NA functional balance is one of the keys to develop excellent vaccine strains (Murakami S, et al. Growth Determinants for H5N1 Influenza Vaccine Seed Viruses in MDCK Cells[J]. Journal of Virology, 2008, 82(21):10502.). For ensuring the functional balance between vaccine strains HA and NA, the two genes are generally derived from the same virus strain. Introduction of heterogenous NAs may disrupt the functional balance between HA-NA, thus reducing the growth and replication capacities of viruses, even resulting in recombinant viruses unable to be rescued. In general, such risks would increase continually as the similarity of the introduced NA gene is reduced (compared with homogenous NAs). Replacements among different subtypes of NA always affect biological properties in terms of replication and growth, of the rescued recombinant viruses. This is also the reason why there are only few advantageous subtype combinations in nature (e.g., common H9N2, H5N1, H7N9, etc.), rather than random combinations of HA-NA (e.g., rare H9N1, H5N9, etc.)(Wagner R et al, Functional balance between haemagglutinin and neuraminidase in influenza virus infections[J]. Reviews in Medical Virology, 2002, 12(3):159). Rudneva et al used different combinations of N1 gene and subtypes of HA gene to generate recombinant viruses, and found that the growth properties of the recombinant viruses of the rescued H3, H4, H10 and H13 on chick-embryos are poorer than their wild-type viruses (Rudneva I A et al. Influenza A virus reassortants with surface glycoprotein genes of the avian parent viruses: effects of HA and NA gene combinations on virus aggregation. [J]. Archives of Virology, 1993, 133(3-4):437-450). Due to the great difference of NA protein in types B and A influenza viruses (with the similarity <30%), the success probability of obtaining the A/B chimeric virus by introducing type B NA is small. Moreover, there may be defects in the growth properties of the rescued A/B NA chimeric viruses, and it may needed to be adapted by serial passages in vitro. However, serial passages may introduce adaptive mutations, causing the risk of antigenic drift, thus resulting in great differences between the antigenicity of the prepared vaccine strains and the original wild-type epidemic strains.
Although the existing H5 whole virus inactivated vaccines do have advantages such as being reliable in terms of immune effect and low cost, the fact that they cannot serologically differentiate infected from vaccinated animals (DIVA) seriously affects monitoring on the virus epidemic, thus hindering the thoroughly decontamination of H5 avian influenza in the farms. The presence of highly pathogenic avian influenza diseases in the farms cannot be eliminated completely, such that the highly pathogenic H5 virus has the risk of persistently threatening the public health. Therefore, it is needed currently to prepare a new H5 avian influenza vaccine strain which can differentiate infection from vaccination.

H5 avian influenza vaccine strain which differentiates infected from vaccinated animals, preparation method therefor, and application

Zhejiang Difference Biological Technology Co., LTD.


A method for forming a resistive memory cell within a memory array includes forming a patterned stopping layer on a first metal layer formed on a substrate and forming a bottom electrode into features of the patterned stopping layer. The method further includes forming a resistive memory layer. The resistive memory layer includes a metal oxide layer and a top electrode layer. The method further includes patterning the resistive memory layer so that the top electrode layer acts as a bit line within the memory array and a top electrode of the resistive memory cell.

There is a frequent demand for smaller devices with more memory. Some efforts have been initiated in resistive memory as a mechanism for creating more memory in less space. Resistive memory systems use a resistive element that can change and maintain the value of its resistivity based on applied electrical conditions. Resistive memory systems use a resistive element that can change and maintain the value of its resistivity based on applied conditions. An example of such a resistive switching device is a metal-insulator-metal device.
A metal-insulator-metal device can be set to a low resistive state when certain electrical conditions form a current path through the insulator material. Alternatively, the device can be set to a high resistive state when this certain applied electrical conditions break this path. Of practical importance, a metal-insulator-metal device can be used to represent logical values. For example, a high resistive state may be used to represent a logical '1' while a low resistive state may be used to represent a logical '0'.
Resistive memory systems are often constructed as an array of resistive memory cells, with each cell being placed on intersecting conductive lines. Typically, such an array is formed in several layers. There is a layer for the bottom conductive lines, a layer for the bottom electrodes of the resistive memory cell, a layer for the insulator portion of the resistive switching device, a layer for the top electrode of the resistive switching device, and a layer for the top intersecting conductive lines. Each of these layers is specifically formed through standard photolithographic patterning processes. It is desirable, however, to be able to fabricate such memory arrays in as few steps as possible.

Resistive memory cell array with top electrode bit line

Taiwan Semiconductor Manufacturing Company, Ltd.


Compressor arrangement having an axial compressor and a radial compressor which are arranged axially one behind the other on a common driveshaft which can be coupled to a drive and which each have a compression fluid input and a compression fluid output. The axial compressor is provided with first control elements and the radial compressor is provided with second control elements. The first control elements and second control elements are controllable separately so that the axial compressor and the radial compressor are controllable separately.

1. Field of the Invention
The invention is directed to a compressor arrangement having an axial compressor and a radial compressor.
2. Detail Description of Prior Art
A combined axial/radial turbine is known from DE 547 354 C.
A compressor installation comprising a four-stage transmission turbo compressor preceded by an axial compressor is known from DE 1 628 242 A1.
A multistage transmission turbo compressor having interstage cooling and comprising axial and radial stages is known from DE 1 959 754 A1.


Disclosed herein is a fluid collection pouch which is extremely simple in design. The pouch utilizes a blank of fluid impervious material having a generally triangular shape including a first side and a second side joined at a common end point to themselves and at their distal ends to opposite ends of a third side. By joining the first and second sides to one another a fluid receiving chamber is formed with the third side forming an open end to the chamber and the joined distal ends of the first and second sides forming a flap portion which extends above the open end of the chamber. The fluid collection pouch is particularly well-suited for use in surgical procedures in which case it may be joined to a surgical drape in the expected path of fluid run-off or provided with a fenestration in the flap portion for registry with a corresponding fenestration in the surgical drape.

A wide number of surgical procedures involve the use or generation of relatively large amounts of fluids such as blood and irrigation liquids. These fluids are often collected in pouches or bags which are either built into the surgical drape of later affixed to drape of patient in the expected path of fluid run-off. Oftentimes such pouches are not added to the surgical drape due to the expense of the pouch itself. It is therefore an object of the present invention to provide a fluid collection pouch that is extremely simple in design and manufacture thereby helping to reduce the cost of the product whether it is a stand alone item or incorporated directly into an overall drape design. This and other objects of the present invention will become more apparent upon a further review of the following specification, drawings and claims.


A three tube type projection television display device comprising red, green and blue projection tubes, wherein optical axes of projection lenses for the inclined projection tubes are off centered, instead of preparing a number of optical couplers of different sizes, from that of the inclined projection tubes by an eccentricity of .delta. when a projection picture size is varied for correcting a trapezoidal distortion in the same way as in the Scheimpflug rule, providing good registration on the screen and also bringing the projected pictures into focus on the entire screen.

1. Field of the Invention
This invention relates to a projection display device and, more particularly, to a three-tube projection display device for projecting color television pictures on a screen with projection lenses by converging three primary color images displayed on three color projection cathode-ray tubes of red, green and blue.
2. Description of the Prior Art
An optical system for use with a prior-art projection television display device includes three color projection lenses, two of which are inclined relative to a screen (FIG. 1). In such prior-art projection television display device, a green projection tube 10G is normally placed at the center and a red projection tube 10R and blue projection tube 10B are placed at respective opposite sides thereof. Projection lenses 20R, 20G and 20B are then arranged in front of the red projection tube 10R, green projection tube 10G and blue projection tube 10B, respectively.
To compensate image distortions by the projection lenses, optical couplers 30R, 30G and 30B are interposed between the projection lenses 10R, 10G and 10B and the respective three color projection tubes 10R, 10G and 10B.
Three primary color images displayed on the three color projection tubes 10R, 10G and 10B are converged and focused on a screen 40 by means of the projection lenses 20R, 20G and 20B for reconstituting color television pictures thereon.
In projecting the three primary color images on the screen, there is no problem for the projection lens 20G since an optical axis 20G.sub.s thereof is arranged normal to the screen 40; however, there are some problems for the optical lenses 20R and 20B since optical axes 20R.sub.s and 20B.sub.s of the projection lenses 20R and 20B at the right and left sides of the projection lens 20G are inclined relative to the screen 40.
Accordingly, in such a projection display device as described above, face plates 10R.sub.a and 10B.sub.a of the projection tubes 10R and 10B are inclined, in accordance with what is called the Scheimpflug rule, by an amount of .beta. relative to the respective lens surfaces of the projection lenses 20R and 20B to provide entirely focused pictures on the screen 40, even though the optical axes of the projection lenses are inclined thereto (FIG. 2).
The inclined angle of .beta. (hereinafter referred to as a "Scheimpflug angle") between the lens surface and the face plate of the projection lens has the following relation with the projection screen: EQU (1/m) tan .theta.=tan .beta.
where,
m=magnification (optical power) of the projection lens 20 PA1 .theta.=the angle between the lens surface of the projection lens 20 and the screen 40 PA1 R=curvature of plano-convex face plate (curved on the side of phosphor) of the projection tube PA1 m=magnification of the projection lens PA1 n=refractive index of the coolant PA1 .theta.=angle of incidence to the screen
In FIG. 3, there is shown an optical coupler 30 coupled with the face plate of the projection tube 10. The optical coupler 30 is provided with a meniscus lens 30b, which is for compensating distortion of the projected image on the screen, mounted on a center-holed optical coupler frame 30a on the side thereof facing the projection lens 20 by employing a packing 30c, and then attached to the face plate 10a of the projection tube 10 on the side thereof facing the projection tube 10 by employing another packing 30d.
A space formed by the meniscus lens 30b, an inner wall of the optical coupler frame 30a and the face plate 10a of the projection tube 10 is filled with a liquid coolant for cooling the face plate 10a. The optical axis of the meniscus lens 30b is aligned with that of the projection lens 20.
Further, in FIG. 3, the angle between the meniscus lens 30b and the face plate 10a of the projection tube 10 is set to the Scheimpflug angle of .beta.; however, it is possible to arrange the meniscus lens 30b in parallel with the face plate 10a of the projection tube 10 and incline, as shown in FIG. 4, the optical axis of the projection lens 20 by an angle of .beta. with respect to the optical axis of the projection tube 10 for providing the same effect as that of the configuration shown in FIG. 3. In FIGS. 3 and 4, element 20a designates a projection lens frame for mounting the projection lens 20 on the optical coupler frame 30a.
In the projection television display device of the type as described above, if the size (normally indicated by the diagonal length in inches) of the projection picture is changed, the angle .theta. between the optical axes of the projection lens at the center and each of the projection lenses at the right and left (or the angle .theta. between the projection lens surface and the screen) and the magnification m of each projection lens must be varied in accordance with the projection distance and, accordingly, the Scheimpflug angle .beta. will also be varied in accordance with the size of projection picture.
In accordance with the prior art projection television display device, therefore, there have been employed a number of dedicated optical coupler frames in order to provide different Scheimpflug angles .beta., between the surface on which the meniscus lens is mounted and the surface which the face plate abuts, in accordance with the picture size selected to be projected on the screen. However, since the optical coupler frame of this kind has normally been manufactured by aluminum die casting and the like, a number of molds have been prepared for different projection picture sizes, thus resulting in a problem of high production cost.
Further, it has been required to incline the projection tubes precisely in order to provide the registration of three primary color images on the screen. This in turn has caused problems such that tight toreance mounting parts are required to mount the projection tubes whenever the projection picture size is changed and, moreover, no manufacturing jigs can be used in common for producing such mounting parts.
It is therefore an object of this invention is to eliminate problems encountered by the prior art projection television display device and to provide a projection television display device wherein an optical coupler frame can be utilized for any picture size of projection television display by off-setting the centers of a meniscus lens and projection lens from that of a projection tube.

Three tube color television projection display device


A power supply circuit is equipped with a first amplification path 10 in which a first potential is input and that supplies current to an output terminal when a control signal is in a first state; a second amplification path 20 in which a second potential is input and that absorbs current from the output terminal when a control signal is in a second state; an intermediate potential forming circuit that forms a third potential between the first potential and the second potential; and a comparison circuit 30 that compares the third potential with a potential at the output terminal to form a control signal and supplies the same to the first and second amplification paths.

Technical Field of the Invention
The present invention relates to a power supply circuit such as a LCD driver, and more particularly to a voltage follower type power supply circuit that supplies loads by a push-pull method.
Conventional Technology
In the conventional power supply circuits such as LCD drivers, a push-pull type shown in FIG. 5 is known. The power supply circuit shown in FIG. 5 includes a first amplification path 100 that supplies current to an output terminal using a P-channel transistor at its output stage, and a second amplification path 200 that absorbs current from the output terminal using an N-channel transistor in its output stage. The power supply circuit is fed with a first potential V10 and a second potential V20 that are obtained by voltage-dividing an input potential VH at a high potential side and an input voltage VL at a lower potential side by resistors R10, R20 and R30. Since the second potential V20 at a lower side is supplied to the first amplification path 100, and the first potential V10 at a higher side is supplied to the second amplification path 200, the output transistor of the first amplification path 100 and the output transistor of the second amplification path 200 do not normally operate at the same time.
However, when threshold voltage or the like of transistors that for differential pairs of differential amplifiers included in the first amplification path 100 or second amplification path 20 changes due to process deviations, a problem occurs in that the output transistor of the first amplification path 100 and the output transistor of the second amplification path 200 may operate at the same time, and in this instance, a large current flows. On the other hand, when a value of the resistor R20 is increased to increase an offset between the first potential V10 and the second potential V20, a problem occurs in that the output voltage of the power supply circuit fluctuates in a wave-like manner.
It is noted that Japanese laid-open patent application SHO61-79312 describes a DC amplifier equipped with an offset adjustment device that controls the midpoint of the common source resistance of a first stage amplifier by inputting a direct current component included in an output of the amplifier in a window comparator and, when it exceeds a specified level, sending control signals to a multiplexer successively by operating a comparison resistor.
Also, Japanese laid-open patent application HEI 7-106875 describes a semiconductor integrated circuit equipped with differential transistors, a power supply transistor connected to commonly connected source electrodes of the differential transistors, a resistor and a power supply transistor connected in parallel therewith, a comparator that compares voltages of both ends of the resistor with a reference voltage and feeds back an output to the two power supply transistors.
However, the techniques described in these references are provided for adjusting a DC offset of an output potential, but not for controlling a push-pull operation at an output stage.
In view of the above, it is an object of the present invention to provide a power supply circuit that supplies power to a load by a push-pull method in which operations of a P-channel transistor and an N-channel transistor in an output stage are controlled, such that large currents that may flow due to process deviations or the like can be prevented.
To solve the problems described above, a power supply circuit in accordance with the present invention comprises: a first amplification path in which a first potential is input and that supplies current to an output terminal when a control signal is in a first state; a second amplification path in which a second potential is input and that absorbs current from the output terminal when a control signal is in a second state; an intermediate potential forming circuit that forms a third potential between the first potential and the second potential; and a comparison circuit that compares the third potential and a potential at the output terminal to form a control signal and supplies the same to the first and second amplification paths.
In the above embodiment, the first amplification path may include a negative feedback amplifier that uses a P-channel transistor at an output stage, and the second amplification path may include a negative feedback amplifier that uses an N-channel transistor at an output stage.
Also, the intermediate potential forming circuit may form the third potential by voltage-dividing the first potential and the second potential.
By the power supply circuit of the present invention having the structure described above, the third potential that defines a reference potential and a potential at the output terminal are compared to control the operations of the first and second amplification paths, whereby large currents that may flow due to process deviations or the like can be prevented.


A dehydration system has improved membrane performance. The dehydration system includes a dehydrating apparatus 1 comprising, in a dehydrating apparatus body, a water separation membrane module in which a water separation membrane having at least one flow path extending in the up and down direction to cause a liquid 50 to pass through is provided with a liquid inlet at the bottom thereof and a liquid outlet at the top thereof; and a shell 11 defined by the outer surface of the water separation membrane module and the inner wall of the dehydrating apparatus body, wherein water in the liquid permeates the water separation membrane while the liquid rises in the water separation membrane, and moves in the shell, whereby the liquid is dehydrated; a pressure reducing device 13 for reducing the pressure of the shell 11; a pressure device for pressurizing the liquid before the liquid is fed to the water separation membrane module; and a heating device for heating the pressurized liquid.

As a fuel source to replace fossil fuels, ethanol has attracted attention, and the market size thereof is predicted to be 55 million kiloliters in the year 2010. However, to use ethanol as a fuel, a crude product obtained from a biological raw material such as corn must be distilled and refined, and this must be dehydrated to at least 99.5 wt %.
Conventionally, in dehydrating, a dilute ethanol aqueous solution has been distilled in a distilling column so as to be concentrated to a point close to the azeotropic point of an aqueous ethanol, and then the solution has been dehydrated.
As a method for dehydrating an azeotrope, a method is available in which an entrainer is added to the azeotrope, and dehydration is accomplished by azeotropic distillation. However, the method requires a process in which a three-component azeotrope is distilled, and furthermore, the entrainer must be recovered. Therefore, the method has some drawbacks such as large amount of heat energy being required.
Another method is available in which plural molecular sieve tanks are arranged in parallel, and dehydration is accomplished while these tanks are switched over in a batch mode. This method also has a drawback in that the regeneration of the molecular sieve tank consumes substantial amounts of energy.
Furthermore, there has been known a method in which water is separated from a liquid mixture that is mutually completely soluble by a membrane separation process using the pervaporation method using a membrane separator (Patent Document 1: Japanese Unexamined Patent Application Publication No. 7-124444). The membrane separation process using the pervaporation method has advantages of high separation performance and energy saving in the separation of a liquid mixture that is mutually soluble.    Patent Document 1: Japanese Unexamined Patent Application Publication No. 7-124444

Dehydration system and dehydration method


A method of forming a polysilicon layer includes the steps of: loading a semiconductor substrate in a CVD reactor wherein a gate insulating layer is formed on the substrate; decompressing the reactor; depositing a first polysilicon layer on the substrate by flowing an SiH4 gas into the reactor; forming a plurality of Sixe2x80x94N bonds on the first polysilicon layer by maintaining atmospheric pressure of the reactor by filling the reactor with nitrogen gas; decompressing the reactor; and depositing a second polysilicon layer on the first polysilicon layer by flowing SiH4 gas into the reactor.

This application claims the benefit of Application No. 99-34962, filed in Korea on Aug. 23, 1999, which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a method of forming a polysilicon layer, and more particularly, to a method of forming a polysilicon layer for dual gates.
2. Discussion of the Related Art
A complementary MOSFET (CMOS) consisting of NMOS and PMOS is widely used in the integrated circuit field. As the size of devices is reduced, a p+ polysilicon gate is used for a PMOS device. Degradation of performance characteristics of devices using the p+ polysilicon gate, such as threshold voltage fluctuation and ruined reliance of gate insulating layers, has been observed. This device degradation is a result of penetration of boron into thin gate insulating layers or diffusion of boron into a channel region in a silicon substrate.
Referring to FIG. 1A, a gate oxide layer 2, 80 xc3x85-thick, is formed on an n-type silicon substrate 1. Referring to FIG. 1B, a first polysilicon layer 3, 1000 xc3x85-thick, is deposited on the gate oxide layer 2 by a low-pressure CVD (LPCVD) at 625xc2x0 C. Referring to FIG. 1C, a silicon nitride layer 4 is generated by nitridizing the first polysilicon layer 3 in NH3 at 900xc2x0 C. and a pressure of 120 mTorr. Next, the silicon nitride layer 4 is removed by dilute HF (not shown). Nitrogen atoms are distributed on a surface of the first polysilicon layer 3. Referring to FIG. 1D, a second polysilicon layer 5, 1000 xc3x85-thick, is deposited by LPCVD at 625xc2x0 C. Ion implantation of BF2+ on the second polysilicon layer 5 is performed with an implant dosage of 5xc3x971015 ions/cm2 and an implantation energy of 50 keV. A polysilicon oxide layer 6 is formed on an upper part of the second polysilicon layer 5 by a first annealing in O2 ambience at 800xc2x0 C. for 30 minutes followed by a second annealing in N2 ambience at 900xc2x0 C.
A nitrogen barrier in the first polysilicon layer 3 prevents fluorine ions from spreading out and also reduces an amount of fluorine ions in the gate oxide layer 6, thereby decreasing the penetration of boron due to fluorine ions. In a p+ polysilicon gate structure of at least two layers of polysilicon, an interface layer 31 between the first polysilicon layer 3 and the second polysilicon layer 5 or between the second polysilicon layer 5 and a third polysilicon layer (not shown) is nitridized by high temperature gas nitridization using NH3 or N2O, thereby generating and accumulating numerous nitrogen atoms at the interface layer 31 as well as at other interface layers between the gate oxide layer 2 and the first polysilicon layer 3. The nitrogen atoms are prevented from spreading out by the fluorine ions.
A conventional method of forming a polysilicon layer uses an active gas, such as NH3 to form an interface layer and requires a subsidiary gas supply. When an n+ gate of NMOS in dual gates is formed, diffusion of arsenic (As) as a dopant in the interface layer is delayed, thereby decreasing doping efficiency. Thus, a previous ion-implantation is required to overcome this decreased doping efficiency. Another dopant, such as phosphorous (P), which has relatively faster diffusion and activation rates than those of As, should be implanted inside the n+ gate to the proper depth. Moreover, dopants accumulate in the interface layer 31 due to diffusion delay to reduce the activation rate, thereby increasing a shear resistance of polysilicon.
Accordingly, the present invention is directed to a method of forming a polysilicon layer that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. An object of the present invention is to provide a method of forming a polysilicon layer which prevents boron penetration in a PMOS.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a method of forming a polysilicon layer includes the steps of: loading a semiconductor substrate in a CVD reactor wherein a gate insulating layer is formed on the substrate; decompressing the reactor; depositing a first polysilicon layer on the substrate by flowing an SiH4 gas into the reactor; forming a plurality of Sixe2x80x94N bonds on the first polysilicon layer by maintaining atmospheric pressure of the reactor by filling the reactor with a nitrogen gas; decompressing the reactor; and depositing a second polysilicon layer on the first polysilicon layer by flowing SiH4 gas into the reactor.
In another aspect of the claimed invention, a method of forming a polysilicon layer includes the steps of: loading a silicon wafer in a CVD vertical reactor, wherein a gate oxide layer is formed on the wafer and wherein the reactor maintains atmospheric pressure at 625xc2x0 C. and is purged by nitrogen; decompressing the reactor to 50.5 Pa; depositing a first polysilicon layer on the wafer by flowing an SiH4 gas into the reactor; forming a plurality of SiN bonds on the first polysilicon layer by maintaining atmospheric pressure of the reactor by filling the reactor with a nitrogen gas; decompressing the reactor to 50.5 Pa; and depositing a second polysilicon layer on the first polysilicon layer by flowing SiH4 gas into the reactor, wherein the second polysilicon layer is formed to be thicker than the first polysilicon layer.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Hyundai Electronics Industries Co., Ltd.


A processor is described herein that is configured to switch between a first instruction issue mode of the processor and a second instruction issue mode of the processor based at least in part on a characteristic associated with a plurality of instructions. The first instruction issue mode and the second instruction issue mode are associated with different energy consumption characteristics. Also, the first instruction issue mode may be an out-of-order instruction issue mode and the second instruction issue mode may be an in-order instruction issue mode.

Different instruction issue modes have different power and performance trade-offs. Processors with logic units implementing in-order instruction issue modes issue instructions in the order they are fetched, allowing for a simple, energy efficient pipeline. While energy efficient, in-order instruction issue modes exhibit lower performance than out-of-order instruction issue modes because the in-order instruction issue modes must stall on miss events (e.g., waiting for an operand that has not been written back to an operand buffer or written to a registry file).
Processors with logic units implementing out-of-order instruction issue modes execute instructions based on their dependencies, providing higher performance by tolerating dynamic latencies. Out-of-order instruction issue modes, however, consume more energy than in-order instruction issue modes, as logic units implementing out-of-order instruction issue modes are more complex than logic units implementing in-order instruction issue modes. For instance, they must be able to perform dynamic scheduling, which consumes additional power.

Energy efficient multi-modal instruction issue


A signaling method for use in a communication network, in particular a unified network, for supporting a communication along a communication path (12) via a plurality of in-path network infrastructure elements (6, 8, 10) of the network. A service element (26, 28) of the network which is located off the communication path triggers an in-path network infrastructure element (6) and the triggered in-path network infrastructure element initiates in-path signaling along the communication path. In particular, the service element may send a message to a terminating end point of the communication, which message is intercepted by the network infrastructure element (6) closest to the terminating end point, which closest network infrastructure element initiates the in-path signaling.

The term unified network is used herein to describe a network comprising a plurality of interfaced networks. The unified network may include an internet, which may be a public or private network, and a plurality of other networks connected to each other via the internet. As an example, the unified network shown in FIGS. 1 and 2 includes a public network, eg. public internet (16), and one or more local or private networks, eg. intranets (18, 20, 22), with which the public network is interfaced. The private networks may be operated by small/medium enterprises, such as companies or academic institutions. In such unified networks, communications are made which cross boundaries between different networks. For example, a communication may be made between the different private networks (eg, between intranet (18) and intranet (20)) via a public network (eg. internet (16)) across the boundaries between the public and private networks. The communications are made between application aware devices which may be small end user gateways (4) or user equipments (2, 24), such as telephone devices, computing devices, video conferencing devices, etc. In order to support certain classes of communications between application aware devices across boundaries between different networks, signaling requests may need to be made requesting services from network infrastructure elements (6 to 10) in the communication path. The network infrastructure elements (6 to 10) may be routers or switches with inbuilt processing capabilities for provisioning the network services.
The private networks (18, 20, 22) may operate different applications from each other, for example for handling media transfer, and are likely to operate different applications from those, such as Internet Protocol (IP) used for handling media transport over the public network (16). In order that a communication can be made between networks, the network infrastructure elements at the boundaries of the networks, for example, elements (7, 8, 9 and 10) which interface a private network with the public network may have Network Address Translator (NAT) application software installed on them. In addition the network infrastructure elements located at the boundaries may also have Firewall application software installed on them for security purposes. For example, a firewall application can be used to ensure that only media having a network address known to the firewall application can enter the private network. Therefore, in a unified network the application aware devices terminating a communication path from a first network to a second network via a network boundary will not necessarily have an awareness of the intermediate network infrastructure elements over which the communication is to be carried.
This can mean that certain applications supported by the application aware devices will not work over such a communication path. As an example, the NAT application has the effect of interrupting communications for traffic types which include network address and transport port information in their payload, where this information is specific to a particular private network and so is not recognisable on other networks. Traffic types which might be interrupted by a NATs application include:                Voice over Internet (VoIP) control and peer messages (eg. ITU standard H284, Media Gateway Control Protocol (MGCP), ITU standard H323 and Session Initiation Protocol (SIP));        device management and administration protocols (eg. Simple Network Management Protocol (SNMP));        File Transfer Protocol (FTP) in certain cases;        VoIP quality report messages (RTCP);        Trivial File Transfer Protocol (TFTP) and        Domain Name System (DNS) protocol.
In addition, automatic configuration servers (eg. operating using the Dynamic Host Configuration Protocol (DHCP)) may not operate when the servers are in the public network.
If such applications are to operate effectively over a unified network they need to be provided with certain network services. The type of services that need to be requested from the network infrastructure elements may include:                Pinhole opening, in particular packet filters need to be configured correctly to allow media flow traversal;        Bandwidth reservation, in particular for VoIP adequate bandwidth needs to be provided to support an acceptable voice quality; and/or        Network address translation. NATs is needed to provide addresses and ports in order to support proper reachability information to a remote application aware device in a different network.
One signaling method for allocating network services which can be used is in-path signaling, as shown in FIG. 2. In accordance with in-path signaling, the terminating end points (2, 4) of a communication across the unified network themselves request the required network services required to support the communication from network infrastructure elements (6, 8, 10) along the communication path (12). The requests for services from the terminating end points travel along the communication path as shown by dotted line (14). This ensures that the resource allocated in response to the request for network services is provided along the communication path (12). A disadvantage with in-path signaling is that the terminating end points (2, 4) must have the capability of making the network service requests from infrastructure elements (6, 8, 10) along the communication path (12). This normally requires software to be implemented on the terminating end points, which can be costly, especially where the application aware devices (2, 4, 24) forming the terminal end points are already deployed in customer premises.
An alternative signaling method for allocating network services which can be used is off-path signaling, as shown in FIG. 3. In this case application servers or proxies (26, 28) located off a communications path (12) between terminating end points (2, 4) request the required network services required to support the communication on behalf of the terminating end points of the communication path. The application servers or proxies are control devices deployed on a network for providing the application aware devices (2, 4, 24) with a service, such as a voice service or a video service. For example, the application server (26, 28) may be a VoIP call agent for providing application aware devices with a voice service. However, where there are alternate communication paths across the network between terminating end points (for example a path via infrastructure elements (6, 7, 9) is an alternative to the communication path (12) via infrastructure elements (6, 8, 10)), the application servers or proxies (26, 28) may request network services from network infrastructure which is not on the actual communication path between the terminal end points. For example, application server or proxy (26) may incorrectly request resource from infrastructure (7) and application server or proxy (28) may incorrectly request resource from infrastructure (9). In this case the resource allocated in response to the requests for network services may not be resource on the communication path (12) with the result that there is insufficient resource on the communication path (12) to support the communication. Alternatively, the application servers or proxies (26, 28) may request network services from the infrastructure element on all possible communication paths between the terminating end points which is costly in terms of wasted resource. These problems become highly significant in complex networks or networks where dynamic changes are occurring.

Signaling method for communication networks


A film cooling hole for a turbine airfoil used in a gas turbine engine, where the film cooling hole includes a metering inlet section of constant diameter cross section and a diffusion section having side walls with multiple expansion. The two side walls have an expansion of around 10 degrees and also slant inwards or toward the downstream side wall of from 10 to 45 degrees to provide the addition expansion. The downstream wall also expands at around 10 degrees. For a compound shaped film hole, the multiple expansions are 10 degrees in the downstream direction and 0 to 5 degrees in the radial outward direction. The side wall in the radial expansion direction will at a convergent angle of 10 to 45 degrees. In the radial inward direction, the expansion angle is from 10 to 20 degrees with a convergent side wall angle of from 10 to 45 degrees.

1. Field of the Invention
The present invention relates generally to a gas turbine engine, and more specifically to a film cooling hole for a turbine airfoil.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Airfoils used in a gas turbine engine, such as rotor blades and stator vanes (guide nozzles), require film cooling of the external surface where the hottest gas flow temperatures are found. The airfoil leading edge region is exposed to the highest gas flow temperature and therefore film cooling holes are used here. Film cooling holes discharge pressurized cooling air onto the airfoil surface as a layer that forms a blanket to protect the metal surface from the hot gas flow. The prior art is full of complex film hole shapes that are designed to maximize the film coverage on the airfoil surface while minimizing loses.
Film cooling holes with large length to diameter ratio are frequently used in the leading edge region to provide both internal convection cooling and external film cooling for the airfoil. For a laser or EDM formed cooling hole, the typical length to diameter is less than 12 and the film cooling hole angle is usually no less than 20 degrees relative to the airfoil's leading edge surface. FIGS. 1 and 2 show a prior art film cooling hole with a large length to diameter (L/D) ratio as discloses in U.S. Pat. No. 6,869,268 B2 issued to Liang on Mar. 22, 2005 and entitled COMBUSTION TURBINE WITH AIRFOIL HAVING ENHANCED LEADING EDGE DIFFUSION HOLES AND RELATED METHODS. In order to attain the same film hole breakout length or film coverage shown in FIG. 2, the straight circular showerhead hole in FIG. 1 has to be at around 14 degrees relative to the airfoil leading edge surface. This also results in a length to diameter ration of near 14. Both the film cooling hole angle and L/D exceed current manufacturing capability.
FIG. 2 shows a one dimension diffusion showerhead film cooling hole design which reduces the shallow angle required by the straight hole and changes the associated L/D ratio to a more producible level. This film cooling hole includes a constant diameter section at the entrance region of the hole that provides cooling flow metering capability, and a one dimension diffusion section with less than 10 degrees expansion in the airfoil radial inboard direction. As a result of this design, a large film cooling hole breakout is achieved and the airfoil leading edge film cooling coverage and film effectiveness level is increased over the FIG. 1 straight film cooling hole.
For an airfoil main body film cooling, a two dimensional compound shaped film hole as well as a two dimensional shaped film cooling hole with curved expansion is utilized to enhance film coverage and to minimize the radial over-expansion when these cooling holes are used in conjunction with a compound angle. U.S. Pat. No. 4,653,983 issued to Vehr on Mar. 31, 1987 and entitled CROSS-FLOW FILM COOLING PASSAGE and U.S. Pat. No. 5,382,133 issued to Moore et al on Jan. 17, 1995 and entitled HIGH COVERAGE SHAPED DIFFUSER FILM HOLE FOR THIN WALLS both disclose this type of film cooling hole.
A three dimensional diffusion hole in the axial or small compound angle and variety of expansion shape was also utilized in an airfoil cooling design for further enhancement of the film cooling capability. U.S. Pat. No. 4,684,323 issued to Field on Aug. 4, 1987 and entitled FILM COOLING PASSAGES WITH CURVED CORNERS and U.S. Pat. No. 6,183,199 B1 issued to Beeck et al on Feb. 6, 2001 and entitled COOLING-AIR BORE show this type of film hole.
Another improvement over the prior art three dimensional film hole is disclosed in U.S. Pat. No. 6,918,742 B2 issued to Liang on Jul. 19, 2005 and entitled COMBUSTION TURBINE WITH AIRFOIL HAVING MULTI-SECTION DIFFUSION COOLING HOLES AND METHODS OF MAKING SAME. This multiple diffusion compounded film cooling hole starts with a constant diameter cross section at the entrance region to provide for a cooling flow metering capability. The constant diameter metering section is followed by a 3 to 5 degree expansion in the radial outward direction and a combination of a 3 to 5 degree followed by a 10 degree multiple expansions in the downstream and radial inboard direction of the film hole. There is no expansion for the film hole on the upstream side wall where the film cooling hole is in contact with the hot gas flow.
U.S. Pat. No. 4,653,983 issued to Vehr on Mar. 31, 1987 and entitled CROSS FLOW FILM COOLING PASSAGE discloses a regular shaped film cooling hole of the prior art with the film ejection stream located above the airfoil surface in which vortices form underneath the film cooling discharge from the hole. The film cooling hole is the standard 10-10-10 expansion file hole where the two sides and the bottom of downstream side of the hole all have degrees of expansion. The film flow will penetrate into the main stream and then reattach to the airfoil surface at a distance of around 2 times the film hole diameter. Thus, hot gas injection into the space below the film injection location and subsequently a pair of vortices is formed under the film flow. As a result of the shear mixing, the film effectiveness is reduced. The film layer of cooling air reattaches to the airfoil surface downstream from the vortices that are formed.

Shaped film cooling hole for turbine airfoil


An articulated forklift truck for use in narrow aisles comprises a front chassis section (10) having a first pair of ground-engaging wheels (20) and a rear chassis section (12) having a second pair of ground-engaging wheels (22). The front chassis section (10) carries a mast (16) and lift forks (18) and is pivoted to the rear chassis section (12) about a substantially vertical axis (14) to allow the truck to be steered. Both front wheels (20) but only one of the rear wheels (22) are driven by electric of hydrostatic motors (24, 26).

A typical narrow-aisle articulated forklift truck comprises front and rear chassis sections each having a pair of wheels on a respective common axis. The rear wheels are driven, while the front wheels are non-driven. The chassis sections are pivoted together about a vertical axis so that the front chassis section can be turned at an angle at or approaching 90° relative to the rear chassis section to allow the truck to insert loads into, and remove loads from, the face of the aisle, i.e. normal to the length of the aisle.
Clearly, as the steering angle increases the inner rear wheel, i.e. the wheel on the inside of the path taken by the truck, will turn more slowly than the outer rear wheel, and in fact may stop altogether or reverse if the axis of the front wheels coincides with or lies inside the ground contact point of the inner rear wheel at large steering angles. In conventional narrow-aisle articulated forklift trucks this leads to tyre wear and difficulties in manoeuvring and controlling the truck. At large steering angles, too, the rear driving wheels will tend to drive the forklift straight ahead (this is known as "dozing on"), with the front wheels skidding sideways.
It is an object of this invention to provide a construction of forklift truck in which this problem is avoided or mitigated.


A multi-use craftsman table (10) for connection of at least one of a plurality of tools (14) for performing a variety of operations on wood work pieces is disclosed by the present invention. The multi-use craftsman table (10) includes a tool table top (16) and a bracket (78) having at least one clamp (80, 82) for releasably securing at least one of the plurality of tools (14) thereto connected to the tool table top (16). The tool table top (16) includes a face side and a bottom side. The face side includes a recess (25) extending therethrough, and first and second grooves (28) extending on either side of the recess (25) and along the length of the face side. The bottom side includes means for connecting (106) the bracket (78) thereto wherein the at least one of said plurality of tools (14) is aligned with the recess (25). At least one leg (18) is releasably connected to the bottom side of the tool table top (16). The at least one leg (18) includes a top end and bottom end (20), the top end is releasably connected to the bottom side of the tool table top and the bottom end includes a machined slot (22) for receiving a clamp (24). The clamp (24) acts to secure the multi-use craftsman table (10) to a table top (34) of a work table (32).

1. Field of the Invention
The instant invention relates generally to machine shop tools and, more specifically, to a multi-use craftsman table.
2. Description of the Prior Art
Numerous machine shop tools have been provided in the prior art. For example, U.S. Pat. Nos. 2,619,135 to Callaway; 3,071,889 to Silver; 4,649,608 to Fresard et al.; 5915,148 to Fox and 5,009,255 to Fournel all are illustrative of such prior art. While these units may be suitable for the particular purpose to which they address, they would not be as suitable for the purposes of the present invention as heretofore described.


A magnetic head device is disclosed. The magnetic head device having a levitation attitude formed by an air stream on a surface thereof when a recording medium moves. A levitation height of a magnetic function unit can be stabilized even when air density of an operating environment is changed. In a middle region of a slider of a magnetic head device, a deep concave bottom portion is provided and a levitation pressure is not substantially generated. The levitation is exerted to a front positive pressure surface located in front of the middle region and a rear positive pressure surface located in the rear of the middle region.

Previously disclosed is a magnetic head device that has a slider that faces a magnetic recording medium and a magnetic function unit provided in an end portion of a ring side of a tray of the slider. The magnetic head device records a magnetic signal in the magnetic recording medium such as a hard disk and reads out the magnetic signal recorded in the magnetic recording medium. The magnetic function unit has a reproducing function unit where an MR effect or a GMR effect is used and a recording function unit where magnetic materials such as a york, a coil and the like are thin-filmed.
The slider of the magnetic head device is suppressed on the surface of the magnetic recording medium by an elastic member such as a load beam, but when the magnetic recording medium rotates, the slider levitated from the magnetic recording medium by an air stream (air pairing) flowing between the surface thereof and the slider, thus predetermined levitation height is set between the magnetic function unit and the magnetic recording medium.
In this type of magnetic head device, a positive pressure surface that generates a levitation pressure by the air stream and a negative pressure generating surface retreats farther than the positive pressure surface are formed on sides of the magnetic recording medium in the slider that faces each other. The slider has an adequate levitation attitude on the surface of the magnetic recording medium by a balance between the levitation pressure exerted on the positive pressure surface and an absorption force to the magnetic recording medium generated on the negative pressure generating surface to stabilize the levitation height.
In order to enhance a magnetic recording density to the magnetic recording medium, and speed-up the recording speed and the reproducing speed, the levitation height from the magnetic function unit is generally set to be lowered as much as possible.
In the magnetic head device according to JP-A-10-283622 (U.S. Pat. No. 6,021,020) described below, in a facing side that faces the magnetic recording medium of the slider, a comparatively deep cratering is formed in an intermediate part of an anterior-posterior direction. The positive pressure surface has a comparatively wide area that is formed at a front part, which is farther than the cratering. The positive pressure surface has a comparatively small area that is formed at a rear part farther than the cratering. This magnetic head device decreases the levitation height by generating the levitation pressure only in a front part and a rear part of the slider without substantially generating the levitation pressure in the middle cratering part.
In the known magnetic head device, the variation of the levitation height that is changed by the air density has a low levitation of the slider. When a levitation distance of the slider is shortened with respect to the magnetic recording medium, the levitation height can be lowered by fluctuating in correspondence with the lowering of the air density based on the altitude difference. When the known magnetic head device is used at high altitudes, such as in an aircraft, the slider can potentially contact the surface of the magnetic recording medium. This increases the possibility that the magnetic recording medium or the magnetic head device rises will be damaged.
In the magnetic head device according to Patent Document 1 described above, the low levitation height is realized by generating the levitation pressure only in the front part and the rear part of the slider. However, in this configuration, when the air density of the operating environment is lowered, the levitation height of the slider is also lowered, thus damage may occur.

Magnetic head device having slider and magnetic function unit


A pitch-compensated induced current position transducer includes a scale having a plurality of scale elements arranged along a measuring axis and a read head positioned adjacent to and movable relative to the scale. The read head has a transmitter winding that generates a changing magnetic field and at least one receiver winding. One of the transmitter winding and receiver winding is formed from a spatially modulated section having an associated phase. The spatially modulated section has flux coupling areas distributed relative to a plurality of polarity zones. The spatially modulated section has at least one pitch balancing section. In one type of pitch balancing section the positive polarity winding loops and the negative polarity winding loops have their centroid axes aligned. The total flux coupling area in at least one polarity zone may optionally be different than the total flux coupling area in an adjacent polarity zone while the total negative flux coupling area remains equal to the total positive flux coupling area. In general, the pitch balancing sections are configured so that the overall centroids of all spatially modulated sections are aligned along the measuring axis. The distribution of the flux coupling area may be symmetrical.

1. Field of the Invention
This invention relates to sensing movement or position between two members by means of signals induced by magnetic fields. More particularly, this invention is directed to an induced current position transducer that compensates certain potential signal errors for a read head that is not perfectly parallel to a scale member.
2. Description of Related Art
Various movement or position transducers are currently available, such as optical, capacitive, magnetic and inductive transducers. These transducers often involve placing a transmitter and a receiver in various geometric configurations to measure movement between two members of the transducer.
Optical, capacitive, and magnetic transducers, are sensitive to contamination. Therefore, using such transducers in most manufacturing or shop environments is impractical. Using such transducers in a shop environment requires expensive and sometimes unreliable environmental seals or other methods of encapsulating the transducer to keep dust, oils and ferromagnetic particles from contaminating the transducer.
Pending U.S. patent application Ser. No. 08/441,769, filed May 16, 1995, and herein incorporated by reference in its entirety, describes an induced current position transducer usable in high accuracy applications. Pending U.S. patent application Ser. Nos. 08/645,483 and 08/645,490, both filed May 13, 1996, and both herein incorporated by reference, describe incremental position inductive calipers and linear scales, including signal generating and processing circuits. Pending U.S. patent application Ser. No. 08/788,469, now U.S. Pat. No. 5,886,519, Ser. No. 08/790,494, now U.S. Pat. No. 5,841,274, and Ser. No. 08/790,459, now U.S. Pat. No. 5,894,678, all filed on Jan. 29, 1997, each herein incorporated by reference, describe absolute position inductive calipers and electronic tape measures using this induced current transducer.
This induced current position transducer employs two members that are movable relative to each other. A read head contains an active transmitter for generating a changing magnetic field and a passive receiver for receiving and sensing the field and producing a receiver output signal. A scale includes a plurality of flux modulators. The flux modulators modulate the magnetic field, and thus the induced current in the receiver, depending on the position of the scale relative to the read head.
The transmitter includes a field source that produces a changing magnetic flux through a flux region. The receiver includes a receiver winding arranged in a prescribed pattern of flux-receiving areas along a measuring axis and within the flux region. The receiver winding passively generates a signal in response to the sensed changing magnetic flux. The amplitude and polarity of this signal is a function of the position of the read head relative to the scale. The receiver winding is formed by crossing a conductive element over itself at predetermined intervals to approximate a sinusoidal wave that reverses at one end. In this manner, the receiver winding has adjacent loops having alternating clockwise and counter-clockwise orientations. The magnetic field generated by the transmitter that passes through these loops with alternating orientations will generate EMFs having alternating polarities.
Alternatively, with suitable signal processing such as that detailed in the other U.S. patent applications incorporated herein, the transmitter and receiver/sensor functions may be switched. That is, the transmitter winding may be formed by crossing a conductive element over itself at predetermined intervals to have adjacent loops with alternating clockwise and counter-clockwise orientations. The magnetic fields generated by each of these loops will have alternating polarities. The receiver in this case is a simple loop.
The scale includes a plurality of flux modulators that are regularly positioned at a predetermined interval along the scale. As the scale is moved along the read head, the flux modulators move within the flux region to modulate the magnetic flux proximate to those flux modulators. The flux modulators within the flux region vary the induced current and thus the signal generated by the receiver winding will be a function of the relative position between the read head and the scale.
The induced current transducer, and the calipers, linear scales and electronic tape measures disclosed in these pending U.S. patent applications are readily manufactured using known printed circuit board technology. This transducer system is generally immune to contamination by particles, including ferromagnetic particles, oil, water, and other fluids.
FIG. 1 shows an induced current position transducer 100 having a read head 110 and a scale 120. The read head 110 includes a transmitter winding 112 and at least one receiver winding 114. The receiver winding 114 defines a plurality of positive polarity loops 116 and a plurality of negative polarity loops 118. The positive and negative polarity loops 116 and 118 extend along a measuring axis 130 of the read head 110 within the transmitter winding with a repetition rate corresponding to the scale wavelength .lambda..
The scale 120 includes a plurality of flux modulators 122. The flux modulators 122 can be either flux disrupters or flux enhancers. The flux modulators 122 are positioned at a pitch equal to the wavelength .lambda.. Each flux modulator 122 extends along the measuring axis 130 approximately one-half of the wavelength .lambda. or less.
The flux disrupters are formed by a thin layer of conductive material. The changing magnetic field generated by the transmitter winding 112 generates eddy currents in the thin conductive layer. The eddy currents generate magnetic fields having a direction opposite that of the magnetic field generated by the transmitter winding 112. This reduces, or disrupts, the net magnetic field flux in the regions adjacent to the thin conductive layer flux disrupters.
The flux enhancers are formed by portions of a high magnetic permeability material. The magnetic field flux generated by the transmitter winding 112 preferentially passes through the high magnetic permeability flux enhancers. Thus, the magnetic flux within the flux enhancers is relatively denser, while the magnetic flux in areas laterally adjacent to the flux enhancers is relatively less dense.
In either case, the flux modulators spatially modulate the magnetic flux generated by the transmitter winding and the effective flux coupling between the transmitter and the receiver. It should be appreciated that the flux modulators 122 can indicate an alternating arrangement of flux disrupters or flux enhancers. It should also be appreciated that any of the read head layouts and scale layouts disclosed in the incorporated U.S. Patent Applications can be used with the pitch compensation technique of this invention.
When the read head 110 is positioned over, approximately parallel to, and in proximity to the scale 120, the magnetic field generated by the transmitter winding 112 is modulated by the flux modulators 122. The modulated magnetic field induces a position dependent net EMF in the receiver winding 114.
As shown in FIG. 2, a second induced current transducer 100' does not have a transmitter winding that surrounds the receiver winding. Instead, this second induced current transducer has two transmitter windings 112A and 112B symmetrically placed outside of the receiver winding 114 and connected in series in such a way that the direct field from the transmitter windings 112A and 112B to the receiver winding 114 is minimized. On the scale 120 the flux modulators are replaced with loops 150 that transfer the field from the transmitter area to the area under the receivers.
The current in the upper transmitter loop 112A flows clockwise, causing an induced current in the underlying scale loops 152 that flows counterclockwise. The current in the lower transmitter loop 112B flows counterclockwise, inducing a current that flows clockwise in the underlying scale loops 154. Thus, the alternating loops on the scale carry currents of alternating direction. An example of this second induced current transducer is described in U.S. patent application Ser. No. 08/834,432, filed Apr. 16, 1997, and herein incorporated by reference in its entirety.
In a manner similar to the transducer of FIG. 1, the transmitter and receiver/sensor functions may be switched. In this case, the transmitter may comprise the winding 114 that has alternating polarity loops while the receiver may comprise the winding 112.
When the read head 110' is moved over the scale 120' along the measurement direction, the EMF induced in the receiver winding 114 will alternate as a periodic function of the relative position between the two members with a wavelength equal to the distance between equal polarity loops on the scale. This second induced current transducer 100' is driven with the same kind of signal and the receiver signals are processed in the same way as in the first induced current transducer shown in FIG. 1. Thus, the pitch compensation principles in this invention are equally applicable to the first and second induced current transducers 100 and 100'.
These transducers and other similar types of inductive transducers suffer from undesired errors when the active read head is misaligned relative to the passive scale. One aspect of this misalignment is "pitch". As shown in FIG. 3, in pitch, the read head 110 is rotated from a position parallel to the scale 120 about a pitch axis 132. The pitch axis 132 lies in the plane of the read head 110 and is substantially perpendicular to a measuring axis of the transducer. Thus, one end of the read head will be closer to the scale than the other end of the read head.
The transducers of FIGS. 1 and 2 are shown with single receiver windings 118 and 114, respectively, for simplicity of description. However, practical devices more commonly have multiple receiver windings displaced from each other along the measuring axis, such as windings placed in quadrature, for detecting direction of motion and for other practical reasons. If the read head of one of these induced current transducers is pitched relative to the scale elements, two of the major types of signal errors that can occur are: 1) a net unbalance in the induced amplitudes in the positive and negative loops within a single receiver winding, and 2) a net unbalance in the output signal amplitudes between the multiple receiver windings of the transducers. The unbalanced output of the positive and negative loops within a single receiver winding creates an undesirable position insensitive "DC" offset within the receiver winding signal, and additionally creates an undesirable +/- modulation unbalance within the receiver winding. The different output between multiple receiver windings appears as an undesirable modulation amplitude mismatch between those receiver windings, and additionally, if the individual windings exhibit DC offset, as an undesirable DC offset mismatch between the receiver windings. It should be appreciated that the +/- modulation unbalance and the DC offset mismatch are generally significantly smaller in magnitude than the DC offset and the modulation amplitude mismatch, respectively.
When a conductive scale support material is used, as in a stainless steel caliper beam, the strength of the transmitted field is attenuated compared to when a non-conductive scale base is used. The strength of the transmitted field is attenuated because the transmission field sets up eddy currents in the conductive scale support that in turn induces a counteracting field that reduces the strength of the transmission field. This effect reduces the strength of the response in the vicinity of each portion of the read head receivers to an extent that is dependent upon the gap between the read head and scale. Thus, this effect can distort the desired read head signal relationships when the read head is pitched relative to a conductive support.
The cross-talk from the transmission winding to a receiver winding is defined as the signal at the receiver winding terminal that is caused by the current directly induced by the transmitter field in the receiver windings independent of the flux modulators. In the first induced current transducer shown in FIG. 1, each sub-loop in the receiver windings is subject to a fairly strong directly induced current from the transmitter field. However, each receiver winding includes sub-loops that are wound in alternating directions that cause the induced currents to have alternating polarities. The resulting signals at the terminals of the receiver windings due to cross talk are thus nominally zero, because the number and size of positive and negative loops in each receiver winding are equal. However, balance between the positive and negative currents induced directly by the transmitter winding may be disturbed by an increase in the cross-talk caused by a pitch misalignment of the read head relative to a conductive plane. FIG. 3 illustrates why this happens.
In FIG. 3, read head 110 is positioned over a conductive plane 123, such as a conductive beam supporting the scale 120. Three sets of positive and negative loop pairs 1-3 of the receiver winding are positioned along the measuring axis. Because of the counteracting field generated by the eddy currents in the conductive base, the resulting field in the plane of the winding varies with the distance between the read head 110 and the scale 120. A pitch misalignment of the read head 110 induces an increase in the direct cross-talk between the transmitter winding and the receiver winding because one of the positive or negative loops will be, on average, closer to the conductive base than the other one of the positive and negative loops. In FIG. 3, the negative loops are, on average, closer to the conductive base than the positive loops. Therefore, an imbalance is created because a smaller net transmitter flux passes through the negative loops than through the positive loops. This imbalance shows up as a DC offset in the receiver signal.
If two receiver windings are present and offset from each other along the measuring axis as shown in FIG. 4, an additional problem occurs in that the cross-talk offset will be different in each receiver winding, due to their differing average gap distances. That is, there will be a DC offset mismatch between the two receiver windings. Also, the modulation amplitude in the two receiver windings will be different because of the differing average gap distance.
In the second induced current transducer shown in FIG. 2, the problem with the crosstalk offset is smaller, because the transmitter does not surround the receiver. Furthermore, the direct transmitter field through the receiver windings is nominally balanced by the interaction of the two transmitter windings. However, if this balance is not perfect, or disturbed by a roll misalignment of the read head relative to the scale, a cross-talk offset is created. Roll is a rotation around an axis parallel to the measurement axis.
As described in the incorporated application Ser. Nos. 08/441,769; 08/645,483 and 08/645,490, at least two receiver windings are usually required to unambiguously determine position and movement direction. When multiple receiver windings are present in the first and second transducers, the position is calculated from the relation of signals from these windings.
If the receiver windings are identical but offset from each other in the measurement direction, pitch misalignment of the read head relative to the scale of the transducer causes a modulation amplitude mismatch between the output signals of the two receiver windings. FIG. 4 shows the relative positions of two receiver windings 114A and 114B within the first and second induced current transducers. The two receiver windings 114A and 114B lie in the same plane and are offset one quarter of a wavelength from each other to generate quadrature output signals. As shown in FIG. 4, a pitch misalignment brings the first receiver winding 114A closer to the scale 120 than the second receiver winding 114B. As a result, a modulation amplitude mismatch (signal amplitude mismatch) is created because the signal from the first receiver winding 114A is stronger than that of the second receiver winding 114B. This amplitude mismatch induces a measurement error. This problem exists equally in multiple winding versions of the first and second induced current transducers shown in FIGS. 1 and 2.
FIG. 3 also illustrates how a pitch misalignment generates +/- modulation unbalance in a receiver winding of the first induced current transducer 100 and the second induced current transducer 100'. In other words, within a single winding, the signal modulation of one loop polarity by the scale is larger than the signal modulation of the other loop polarity by the scale. In the first and second induced current transducers 100 and 100', the read heads 110 and 110' and the scales 120 and 120', respectively are preferably positioned perfectly parallel to each other. However, due to manufacturing errors and/or tolerances, and as various components of the first and second induced current transducers 100 and 100' wear, the read heads 110 and 110' and the scales 120 and 120' may become relatively misaligned, as shown in FIG. 3. In particular, the read heads 110 and 110' and scale 120 become pitched by an angle .theta. about a pitch axis 132 from a perfectly parallel orientation indicated by a plane 134.
As shown in FIG. 3, as a result of the pitch, the "3-" negative polarity loop is positioned closest to the scale 120, while the "1+" positive polarity loop is positioned farthest away from the scale 120. Because different EMFs are induced in the receiver loops that are positioned farther away from the scale 120 than those that are closer, the magnitude of the EMF generated in the "1+" positive polarity loop is different than the magnitude of the EMF generated in the "1-" negative polarity loop. Similarly, the magnitude of the EMF generated in the "2-" negative polarity loop is different from the magnitude of the EMF generated in the "2+" positive polarity loop. This is true for each pair of adjacent loops across the read heads 110 and 110' along the measurement axis 130.
When FIG. 3 represents the first induced current transducer 100, the scale elements are flux modulators 122 and the modulation of the induced EMF in each loop will increase as the distance from the scale 120 decreases. Thus, the modulation of the EMF generated in the "1+" loop is less than the modulation of the EMF generated in the "1-" loop, and so on. The net effect is to increase the net modulation signal amplitude for the loop polarity that is on average closer to the scale due to pitch, which defines a +/- modulation unbalance due to the pitch.
When FIG. 3 represents the second induced current transducer 100', the scale elements represent the coupling loops 150. In this case, the inductive coupling provided by the coupling loops 150 between the transmitter winding and a particular loop of the receiver winding will be weaker as the distance from the scale member 120 to any portion of the read head 110' increases. The net effect is again to increase the modulation for the loop polarity that is on average closer to the scale due to pitch, which defines a +/- modulation unbalance due to the pitch. Thus, the read head winding 114 of the induced current transducer 100' shown in FIG. 2 will, in general, be pitch sensitive. It should be noted that the dual-polarity scale 120 shown in FIG. 2 overcomes this pitch sensitivity by theoretically eliminating DC components in the scale field which might interact with the pitch sensitivity of the read head winding 114. However, in general, other scales may be used in which there may exist a significant DC component in the scale field which introduces a DC component in the output signal from the winding 114 when the read head has a pitch misalignment relative to the scale. This creates an error in the output position signal when the processing electronics assumes no unbalance in the winding output signal.
Therefore, an induced current position transducer is needed that is accurate, inexpensive to manufacture and immune to contamination, and can produce substantially balanced signal components that are not adversely affected by pitch misalignment.

Pitch-compensated induced current position transducer