A monolithic ceramic capacitor comprises a plurality of dielectric ceramic layers united into one body, a plurality of internal electrodes formed between adjacent dielectric ceramic layers, and external electrodes formed on opposite sides of the united ceramic each being connected to alternate internal electrodes. The internal electrodes are formed of a copper or a copper alloy. The dielectric ceramic layers are formed of a dielectric ceramic composition including strontium titanate, bismuth oxide and an antireducing agent which prevents the composition from reduction. The antireducing agent has a composition expressed by the general formula: EQU .alpha.MnO.sub.2 +.beta.RO+.gamma.B.sub.2 O.sub.3 +(1-.alpha.-.beta.-.gamma.)SiO.sub.2, or EQU .alpha.Li.sub.2)+.beta.RO+.gamma.B.sub.2 O.sub.3 +(1-.alpha.-.beta.-.gamma.)SiO.sub.2, or EQU .alpha.ZnO+.beta.RO+.gamma.B.sub.2 O.sub.3 +(1-.alpha.-.beta.-.gamma.)SiO.sub.2, or. wherein RO is at least one oxide selected from the group consisting of MgO, CaO, SrO and BaO, and .alpha.,.beta. and .gamma. are molar percentages of the respective components and take a value within the following respective ranges, 5.ltoreq..alpha..ltoreq.20, 10.ltoreq..beta..ltoreq.60, 20.ltoreq..gamma..ltoreq.40.

1. Field of the Invention
The present invention relates to a monolithic ceramic capacitor.
2. Description of the Prior Art
Monolithic ceramic capacitors generally comprise a plurality of stacked dielectric ceramic layers, a plurality of internal electrodes formed between two adjacent dielectric ceramic layers, and external electrodes formed on opposite sides of the stacked ceramic layers and connected to the internal electrodes.
Stronium titanate and a small amount of bismuth incorporated wherein have previously been used as dielectric materials because of their relatively large dielectric constant, small voltage dependency of dielectric constant and small dielectric loss. Typical dielectric ceramics of the prior art include a composition of a SrTiO.sub.3 -PbTiO.sub.3 -Bi.sub.2 O.sub.3.sup..multidot. nTiO.sub.2 system (Japanese patent Laid-open No. 49-30900), a dielectric ceramic composition of a SrTiO.sub.3 - MgTiO.sub.3 - Bi.sub.2 O.sub.3 - TiO.sub.2 - Pb.sub.3 O.sub.4 system (Japanese patent publication No. 59-8923), a dielectric ceramic composition of a SrTiO.sub.3 -CaTiO.sub.3 - Bi.sub.2 O.sub.3.sup..multidot. nTiO.sub.2 system (Laid-open No. 59-20908), and a If such compositions are used in monolithic 60-145951).
If such a composition is applied to monolithic ceramic capacitors, the internal electrodes is should be made of material such as platinum and silver-palladium alloys which have high melting points and high resistance to oxidation at high temperatures. This is because the compositions have high sintering temperatures of not less than 1120 .degree. C. A drawback to using platinum and silver-palladium alloy is their high cost. In addition, if any silver-palladium alloy is used as the internal electrode material, it causes migration of silver into the ceramic layers, resulting in lowering the electrical properties of the capacitors. Further, the silver-palladium alloy causes increased equivalent series resistance of the capacitors because of its low conductivity.
To solve these problems, use of copper or a copper alloy has been proposed as a material for internal electrodes because these materials are low in price and high in conductivity. In order to use copper or a copper alloy as an internal electrode material, it is required to fire the dielectric ceramic composition in a reducing atmosphere since such a material has a low melting point and is easily oxidized at the sintering temperature of the dielectric ceramic compositions of the prior art. However, if the dielectric ceramic compositions of the prior art are fired in reducing atmospheres, the bismuth oxide contained therein is reduced during firing, resulting in lowering of the insulating resistance. Thus, it is impossible to use copper or a copper alloy as a material for internal electrodes. SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an expensive monolithic ceramic capacitor which does not experience decrease in electrical properties as a result of.
According to the present invention, there is provided a monolithic ceramic capacitor including a plurality of dielectric ceramic layers united into one body, a plurality of internal electrodes formed between two adjacent dielectric ceramic layers, and external electrodes formed on opposite sides of the united ceramic layers, each being connected to alternate internal electrodes. The dielectric ceramic layers mainly consists of strontium titanate containing bismuth oxide and an antireducing agent which prevents the composition from reduction. The internal electrodes consist essentially of a copper or a copper alloy.
In a preferred embodiment, the internal electrodes may be incorporated with at least one additive selected from the group consisting of glass frit, dielectric powder, and an antireducing agent. The incorporation of such an additive into the internal electrodes prevents the monolithic ceramic capacitors from delamination between adjacent dielectric layers. The sum of the content of additives in the internal electrodes should be not more than 40 wt%.
It is preferred to use a dielectric ceramic composition of a system, SrTiO.sub.3 -PbTiO.sub.3 -CaTiO.sub.3 -Bi.sub.2 O.sub.3 -SnO.sub.2 -TiO.sub.2, or of a system, SrTiO.sub.3 - MgTiO.sub.3 - Bi.sub.2 O.sub.3 - TiO.sub.2 - Pb.sub.3 O.sub.4 for the dielectric layers of the monolithic ceramic capacitor. Preferably, the dielectric layers are made up of a dielectric ceramic composition expressed by the general formula: EQU .alpha.(Sr.sub.l-x-y-z Pb.sub.x Ca.sub.y Mg.sub.z)TiO.sub.3 +.beta.{Bi.sub.2 O.sub.3.n (Ti.sub.l-m Sn.sub.m) O.sub.2}
wherein x, y, z, .alpha., .beta. and m are mole fractions of the respective components or ingredients, each taking a value within the following respective ranges: .alpha.+.beta.=1.000, 0<.beta..ltoreq.0.300, 0.000 .ltoreq..times..ltoreq.0.500, 0.000 .ltoreq.y.ltoreq.0.500, 0.000.ltoreq.z .ltoreq.0.650, 0.000.ltoreq..times.+y+z.ltoreq.0.750, 0.000.ltoreq.m.ltoreq.0.995, and wherein n takes a value in moles within the following range: 0.00<n.ltoreq.5.00.
To prevent the dielectric ceramic composition from reduction during firing, an antireducing agent may be used therein having a composition expressed by the general formula: EQU .alpha.MnO.sub.2 +.beta.RO+.gamma.B.sub.2 O.sub.3 +(1-.alpha.-.beta.-.gamma.)SiO.sub.2, or EQU .alpha.Li.sub.2 O+.beta.RO+.gamma.B.sub.2 O.sub.3 +(1-.alpha.-.beta.-.gamma.)SiO.sub.2, or EQU .alpha.ZnO+.beta.RO+.gamma.B.sub.2 O.sub.3 +(1-.alpha.-.beta.-.gamma.)SiO.sub.2,
wherein RO is at least one oxide selected from the group consisting of MgO, CaO, SrO and BaO, and wherein .alpha., .beta.and .gamma.are molar percentages of the respective components and take a value within the following respective ranges, 5.ltoreq..alpha..ltoreq.20, 10.ltoreq..beta..ltoreq.60, 20.ltoreq..gamma..ltoreq.40. Copper and copper alloys may be used as a material for internal electrodes;
The incorporation of an antireducing agent into the above basic composition lowers its sintering temperature and prevents it from reduction during firing in a reducing atmosphere. This makes it possible to use copper or a copper alloy as a material for the internal electrodes. In addition, the use of copper or an copper alloy makes it possible to prevent the dielectric layers from migration of the internal electrode material, as well as to reduce the cost of producing the monolithic ceramic capacitors.
The above and other objects, features and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings which show, by way of example only, preferred embodiments thereof.


A compression-type coaxial cable connector having a male adapter nut at the leading end thereof, a slotted body portion and a compression sleeve slidably attached to the body portion and forming the trailing end of the connector. The connector, and each of the components associated therewith, has an axial conduit coextensive with the length thereof. The prepared end of a coaxial cable is inserted into the trailing end of the axial conduit and advanced through the conduit into the body portion until the center conductor of the cable either extends into the adapter nut or is seized by a fixed seizing pin that extends through the leading end of the adapter nut, and the compression sleeve advanced over the body portion to complete the connection. The connector, which, unlike prior art connectors, lacks a center post, is easy to install and is suitable for low frequency (<˜20 MHz) applications.

1. Field of the Invention
The present invention relates to connectors for electrically connecting a coaxial cable to a female receiving port.
2. Prior Art
Coaxial cable connectors adapted to form a secure, electrically conductive connection between a coaxial cable and a receiving port such as, for example, RCA, BNC and Type F receiving ports, are well known in the art. Such prior art connectors are designed for transmission of high frequency signals and are disclosed and discussed, for example, in U.S. Pat. Nos. 5,024,605 to Ming-Hua, 4,280,749 to Hemmer, 4,593,964 to Forney, Jr. et al., 5,007,861 to Stirling, 5,073,129 to Szegda and 5,651,699 to Holliday. U.S. Pat. No. 5,879,191 to Burris, and U.S. Pat. No. 6,217,383 to Holland discuss prior art efforts to provide a coaxial connector which is moisture-proof and minimizes radiative loss of signal from the cable. A radial compression type of coaxial cable connector of the type generally used today, is described in detail in U.S. Pat. No. 5,632,651 to Szegda, and the disclosure of Szegda '651 relating to radial compression coaxial cable connectors is incorporated herein by reference thereto
While The innovative plethora of prior art connectors, some of which are disclosed above, provide improved moisture sealing and/or RF leakage characteristics, all have inherent limitations. The connectors must be designed to fit an exact cable size due to the fixed inner diameter of the ferrule or tubular barbed section into which the outer diameter of the dielectric layer of the cable must fit. The compression type connector designs mentioned above provide waterproofing, better high frequency performance, and higher holding forces on the cable for outdoor applications where the cable is also required to be a structural section of a system.
Another attractive feature of the compression type connector over former ring/crimp types is that the successful completion of the cable/connector installation is obvious after compression thus leading to a much lower level of installer/workmanship errors. Inasmuch as coaxial cable installers are equipped with tools and installation training for compression type connectors, the compression cable/connector attachment method has become popular as well beyond F types to include RCA and BNC type connectors used indoors on home theater equipment.
The present (prior art) compression connectors mentioned above rely upon an inward radial force of the compressing shell onto a fixed, hollow, cylindrical center post or ferrule into which the dielectric layer of the cable is inserted. The braid and jacket of the cable are compressed between the compression cylindrical ring and center post. The dimensions of the inner diameter of the center post must be precisely matched to the outer diameter of the dielectric layer to allow the cable to be inserted into the connector with a reasonably low force as well as to maintain a high holding force of the cable to connector after insertion and compressing. This limitation requires the connector dimensions to be designed to a specific cable dimension.
In the early stages of the higher performance connector development, there were only a few standard coaxial cables used such as RG-59 and RG-6 sizes so that one or two sizes of connectors were needed. An installer could use the outdoor models with water sealing for all applications. Presently, each of the RG-59 and 6 types have many variations with larger shields, teflon and fire retardant dielectrics and outer jackets for plenum use in buildings, softer jackets for flexible bends, and higher stranded shields for flexible use within home theater cabinets. In addition, the standard size specifications for the traditional RG-59 and 6 have changed so the cable designation has little meaning as to dimensions. Accordingly, it has become a requirement to make many sizes of connectors to fit all cables to meet the market needs. Attempts to make a universal design of the compression design have been limited or failures.
Prior art connectors rely on compression over the center post (alternatively referred to herein as "ferrule" or "tubular shank") for secure attachment of the connector to a coaxial cable. Accordingly, the barb on the tubular shank has a relatively high profile or angular pitch, which high profile makes it difficult to force the prepared end of a coaxial cable into the connector. Recent developments in building codes require that coaxial cable installed in particular locations within a structure, such as plenum areas, air return ducts and elevator shafts, have fire retardant jacketing materials. Such new jacketing materials have different physical properties than the standard coaxial cables previously used, such as elasticity, smoothness and thickness, which renders prior art connectors less than optimal for use therewith. There is a need for a coaxial cable connector that can be used with a variety of cable sizes for relatively low frequency applications.


To a canister assembly to be installed in a vehicle body having a differential device mounted on a rear part thereof without reducing the space above a floor panel while ensuring an adequate adsorption chamber volume. The canister assembly (22) comprises a first adsorption chamber (31) for adsorbing fuel vapor introduced from a fuel tank (8); a second adsorption chamber (32) for adsorbing fuel vapor introduced from the first adsorption chamber; and a chamber communication pipe (46) for communicating the first adsorption chamber with the second adsorption chamber; wherein the first adsorption chamber and second adsorption chamber are provided separately from each other on either side of the differential device.

In an automobile, a fuel tank is sometimes provided under a floor panel, and a vapor storage canister (charcoal canister) is provided adjacent to the fuel tank for the purpose of adsorbing fuel vapor that is generated in the fuel tank. To promptly adsorb the fuel vapor generated in the fuel tank, it is desirable to ensure an adequate storage volume, and place the vapor storage canister (which is referred to simply as "canister" in the following description) as close to the fuel tank as possible. Also, as the space available for installing the canister is limited, various proposals have been made so as to optimize the shape and layout of the canister.
As one such technology, it is known to place a canister between a front end and a rear end of a sub-frame attached to a rear part of a vehicle body frame at a higher elevation than the fuel tank so as to be adjacent or substantially adjacent to the lower surface of the floor panel. See patent document 1.
A known canister comprises a canister casing defining a first adsorption chamber filled with activated charcoal for adsorbing fuel vapor introduced from an inlet port and a second adsorption chamber provided in parallel with the first adsorption chamber and filled with activated charcoal for adsorbing vapor fuel released from the first adsorption chamber. A first space is defined in a part of the second adsorption chamber on the side of the inlet port, and a second space is defined in parallel with the first and second adsorption chambers such that the length of the second space as measured along the direction directed toward the inlet portion is longer than that of the second adsorption chamber, and a communication hole is formed in a wall separating the first space and second space from each other to communicate the first and second chambers to each other. The canister casing is formed with an atmospheric port for communicating the atmosphere with the second space, and is provided with a filter for preventing the intrusion of foreign matters into the second space. See patent document 2.    Patent Document 1: Japanese patent laid open publication No. 2004-143966    Patent Document 2: Japanese patent No. 3951427


A fast ring switchover is enabled in packet level processing at the time of ring configuration, and as a result, a system switchover function can be implemented in an Ethernet switch or the like by a ring switchover method in a network constituted of layer 2 switches connected in a ring shape, each layer 2 switch having a path control function and a failure detection function. The ring switchover method includes the steps of providing in each layer 2 switch an address learning table in which a Media Access Control (MAC) address and a corresponding port are stored; on detection of a link failure between mutually neighboring layer 2 switches, transmitting a failure notification frame packet from each neighboring layer 2 switch; and in the layer 2 switch having received the failure notification frame, recording a Media Access Control (MAC) address of said layer 2 switch into the failure notification frame, and transferring the failure notification frame to a neighboring layer 2 switch.

In recent years, there have been increased needs toward constructing intranet corporate networks incorporating access to the Internet and the Internet Protocol (IP). Communication services provided by communication operating companies featuring provision of an end user interface through IP packets has started, in which a variety of methods are employed.
One form of such network configurations is a ring-structured layer 2 Ethernet network (the Ethernet is standardized in the IEEE 802.3.)
In FIG. 1, one exemplary configuration of such a layer 2 Ethernet network is shown. The network accommodated in a backbone network 100 is constituted of layer 2 (L2) switches (or bridges) #1-#8 connected in a ring shape.
Further, the Spanning Tree Protocol (STP) is known as a network configuration protocol. The STP is a protocol for logically making a tree-structured network, so as not to produce a loop structure in a layer 2 network (where layer 2 denotes the second layer in the Open System Interconnection, OSI. As for the STP, for example, refer to ANSI/IEEE Standard 802.1d.
Among switches (bridges) constituting a system, a representative bridge (which is referred to as root bridge) is selected, and a tree-structured network is logically configured from the root bridge. Also in the ring network shown in FIG. 1, it is possible to configure a tree-structured network logically.
The STP enables to configure logical links in FIG. 1, which include a first link directing in the clockwise direction from L2 switch #1 to L2 switch #5, and a second link directing in the counterclockwise direction from L2 switch #1 to L2 switch #6.
To enable such a tree structure by use of the STP, each switch (bridge) transmits a control frame (configuration frame) in an initialization process which is performed in the event of the power switched on. In a bridge receiving the control frame (configuration frame), when an operation system has already been established, the current root bridge (L2 switch #2) is remained as the root bridge, and the added bridge is newly incorporated in the system. Thus system reconfiguration is carried out.
A link weight between bridges is defined as a path cost. After the path cost is added to the value set in the control frame (configuration frame) which is transmitted from the root bridge, the frame is forwarded to a neighboring bridge.
In each switch (bridge), when control frames (configuration frames) are received (that is, two control frames are received totally) from the two ports connected to the ring, the switch (bridge) of interest compares the path costs which are set in the two control frames (configuration frames). As a result of this comparison, the port side which has received the control frame (configuration frame) having a greater path cost is treated as a blocking port, in which entire frames for transmission are blocked.
In the example shown in FIG. 1, the port provided in L2 switch #5 and is directing to L2 switch #6 is regarded as the blocking port. In such a way, a logical tree structure is formed.
Here, in a network set by the STP as described above, when a failure occurs on any link, for example, on a link located between L2 switch #7 and L2 switch #8, data transmission on a link directed from L2 switch #7 toward L2 switch #6 becomes unable. In such a case, it is necessary to remove the block condition having been set in the blocking port of L2 switch #5, as well as to perform a ring switchover so that a link directed from L2 switch #5 toward L2 switches #6 and #7 is established.
In a conventional ring-structured network, the STP (Spanning Tree Protocol) specified in the IEEE 802.1d is usually employed as a method for ring switchover in the event of a failure.
FIG. 2 shows a diagram illustrating STP state transitions in each port of a switch.
In FIG. 2, when the STP is enabled, there exist four states, A, B, C and D. The contents of each state are illustrated below.
(A) Blocking: A state in which a certain port does not take part in forwarding a control frame (configuration frame). In this state, a received control frame (configuration frame) is discarded without forwarding.
(B) Listening: A state in which a control frame (configuration frame) is ready for forwarding. Forwarding the control frame (configuration frame) is temporarily set disabled to prevent from forming a temporary loop.
(C) Learning: A state in which a control frame (configuration frame) is ready for forwarding. In this state, only receiving function is enabled, and a source Media Access Control (MAC) address is learned and registered into a table.
(D) Forwarding: A state in which a control frame (configuration frame) can be forwarded. In this state, a received control frame (configuration frame) is forwarded to a neighboring port.
Among the above-mentioned four states, the state is either (A) Blocking or (D) Forwarding during a stationary state.
Further, in FIG. 2, reference numbers (1)-(5) denote transition conditions, the contents of which are as illustrated below.
(1) A port state is changed from an STP disabled state to an STP enabled state, initiated either by an administrator or in the initial setting.
(2) A port is changed from the STP enabled state to the STP disabled state.
(3) Selection of a root port.
(4) Selection of an alternative port.
(5) Completion of a protocol timer (forwarding time)
Here, in FIG. 2, a port is in (A) Blocking state in the event of a failure. In order to reestablish a link by shifting to (D) Forwarding state, it is necessary to shift from (A) Blocking→(B) Listening→(C) Leaning→(D) Forwarding in the transition diagram shown in FIG. 2.
In order to shift from (A) Blocking→(B) Listening, in other words to perform (3) selection of a root port, a default time of 20 seconds is being set. Further, in order to shift from (B) Listening→(C) Learning, and from (C) Learning→(D) Forwarding, in other words as a transfer time, a default time of 15 seconds is being set, respectively.
Thus, according to the default setting, it is required 50 seconds for a link switchover by use of the STP to shift from (A) Blocking state to (D) Forwarding state in the event of a failure.
As described above, the STP is a protocol for avoiding occurrence of loop path in an L2 network, by which a time of 50 seconds is normally required for a system reconfiguration. This impedes to maintain a session of an application.


The present disclosure provides a flexible graphite sheet and a method for fabricating the same and a composite structure for the same. The method for fabricating a flexible graphite sheet comprises steps of coating an augmenting solution on a first film to form a composite structure, and heating the composite structure such that the first film and the augmenting solution form a flexible graphite sheet, wherein the thermal conducting cross-section of the flexible graphite sheet is larger than the thermal conducting cross-section of the first film, and the thermal conductivity of the flexible graphite sheet ranges from 1200 to 6000 W/m° C.

1. Technical Field
The present disclosure relates to a flexible graphite sheet and a method for fabricating the same and a composite structure for the same, and more particularly, to a flexible graphite sheet with high thermal conductivity and a method for fabricating the same and a composite structure for the same.
2. Description of Related Arts
To increase the thickness of graphite sheets, the conventional method performs a high temperature sintering process on a thick polyimide film to graphitize the polyimide film. However, gases are generated as the high temperature sintering process is performed on the thick polyimide film, and the gas emissions cause the graphite sheet to crack during the graphitization process. To avoid the crack problem, the conventional method alternatively uses glue to adhere several graphite sheets into a stack with a higher thickness. However, the thermal conductivity of the glue is very low, and the overall thermal conductivity of the graphite sheet stack is also very low.
Another conventional method for increasing the thickness of graphite sheets employs the use of artificial graphite sheets and natural expanded graphite sheets, and uses a high temperature laminating process to laminate the artificial graphite sheets and the natural expanded graphite sheets into single graphite sheet bodies. However, the thermal conductivity of natural expanded graphite sheets is low and the overall thermal conductivity of laminated graphite sheets is also very low, although the thickness is increased.

Flexible graphite sheet and method for fabricating the same and composite structure for the same


A method performs an image processing application by expressing the image processing application as a non-negative quadratic program (NNQP) with a quadratic objective, and nonnegativity constraints. A Karush-Kuhn-Tucker condition of the NNQP is expressed as a fixpoint ratio. Then, the fixpoint ratio is determined iteratively until a solution to the image processing application is reached with a desired precision.

As known in the art, a non-negative quadratic program (NNQP)
                                                                                min                  x                                                                                1                    2                                                                          x                    T                                                      Qx                                            -                                                x                  T                                                h                                                                        s              .              t              .                                                                          x                ≥                0                            ,                                                          (        1        )            with vectorsx,h εn,and a symmetric positive semi-definite matrixQεn×n,where T is a transpose operator is ubiquitous in image processing applications, where x is a vector of non-negative quantities, such as light intensities, to be estimated under a squared error norm.
For example, Eq. (1) subsumes a non-negative least squares (NNLS) problem encountered in deblurring and super-resolution applications,
                                                                        min                x                                                                                                                  Ax                    -                    b                                                                    2                2                                                                        s              .              t              .                                                                          x                ≥                0                            ,                                                          (        2        )            withQ=AT A and h=ATb.where A is a blurring or downsampling matrix, and b is a vector of pixel values. Eq. (1) is also the dual of a broader class of convex quadratic programs of the form
                                                                                min                        y                                                                                1                          2                                                                                y                          T                                                                        Hy                                                              -                                                                  y                        T                                                                  f                                                                                s                    .                    t                    .                                                                                Ay                ≥                b                            ,                                                          (        3        )            h are derived from vectors f, b are matrices A, and H via a dual transform.
Such quadratic programs are used in image labeling and image segmentation applications, and image operations that involve solving Poisson equation, e.g., matting. Solutions of Eq. (1) yield solutions of Eq. (3).
Eqs. (1-3) are well know in the prior art. State-of-the-art interior-point, active-set, and primal-dual algorithms offer linear-to-quadratic rates of convergence, but each iteration requires solution of a linear equation at least as large as Qy=z, which can take O(n3) time for a vector y of n values. This is impractical for image processing, where the number n of pixels in a single image can be 107 or larger, Obviously this is an extremely complex operation and cannot simply be performed.
Multiplicative update methods are suitable for very large problems. They allow rough estimates of the solution vector to be improved without solving linear equations. Some well-known examples are the Richardson-Lucy deblurring algorithm, the image-space reconstruction algorithm, and Lee-Seung non-negative matrix factorization algorithm. These will turn out to be special cases of the invention presented here.
However, those applications rely on some combination of strictly nonnegative coefficients, positive definiteness, or favorable initialization for convergence, if convergence is provable at all.

Method for performing image processing applications using quadratic programming

Mitsubishi Electric Research Laboratories, Inc.


A substrate having at least one electrical component disposed thereon; a plurality of discrete electrically conductive fastening units disposed in a pattern on the substrate surrounding the at least one electrical component; a board-level electromagnetic interference (EMI) shield comprising an electrically conductive layer; a plurality of apertures formed in the board-level EMI shield such that the apertures correspond to the pattern of the electrically conductive fastening units; with at least one thermally conductive interface (TCI) material disposed over the at least one electrical component; and wherein the electrically conductive layer of the board-level EMI shield is in electrical contact with at least one electrically conductive fastening unit.

This invention generally relates to an improved board-level electromagnetic interference (EMI) shield for applications where heat dissipation is important. More particularly, the present invention relates to a shield that is easily removable, compatible with single or multi-compartment shield designs, thin in profile, lightweight, and promotes enhanced thermal dissipation of the shielded components. This solution is particularly advantageous for use in small electronic devices, such as cellular phones, personal digital assistants, handheld and laptop computers, among others.
EMI shields limit electromagnetic radiation from entering or exiting sections of a printed circuit board (PCB) containing electrical components. An EMI shield is further defined to be xe2x80x9cboard-leverxe2x80x9d if it attaches directly to the surface of a PCB, and without external or loose fasteners (such as screws or bolts), thereby eliminating a significant source of size and weight from the shielding scheme. Also as a result of this direct surface attachment to the PCB, board-level shields allow for EMI isolation of one or more sections of a PCB surface from one or more sections of the same (or other PCB""s) within a given device. As with other (non-board-level) shielding schemes, board-level shields also allow for EMI isolation of one or more sections of a PCB surface on a device, from other external devices.
Often, electrical components that need to be shielded also generate heat while operating, such as power amplifiers, central processing units (CPU""s), graphics chips, etc. Since the performance of these components often degrades at elevated temperatures, it is typically desirable to facilitate the transfer of heat away from them. This is typically done through the use of conduction, by utilizing a thermally conductive interface (TCI) material and a heat sink. The TCI material fills a gap in the stack-up between the component and the heat sink, and has a thermal conductivity higher than that of air, and typically as high as possible. TCI materials are often made of a conformable elastomer (such as silicone), filled with highly conductive thermal particles. The heat sink can be a finned metal block, a spreader plate comprised of sheet metal or plastic, a heat-pipe assembly, or any structure that enhances the dissipation of heat away from the electrical component and TCI material.
A common type of board-level EMI shield is known as a xe2x80x9ccanxe2x80x9d. A can is soldered to the ground trace on a PCB, directly over the electrical components that need to be shielded. Such cans offer extremely high levels of shielding effectiveness, are typically very reliable, and are well known in the industry. They are often installed in a fully automated fashion via a surface mount technology (SMT) process at the same time the components themselves are installed onto the PCB, using solder paste and a reflow process. Cans are extremely difficult to remove and replace (if the shielded components need to be reworked), because of the complicated de-soldering and re-soldering process.
Often, the components shielded by cans generate significant heat. Cans, however, require mechanical clearance (i.e. an air gap) above the components they are shielding on a PCB, to allow for proper soldering of the can to the ground trace during the reflow process. Because of this necessary clearance, a TCI material cannot be used to fill this air gap, which negatively impacts the transfer of heat away from the component to be shielded. This makes cans an undesirable solution where thermal dissipation is required.
A novel board-level shield is disclosed in U.S. patent application Ser. No. 09/793,754, of Reis, which describes a removable, multi-cavity shield, that utilizes a plurality of discrete electrically conductive fastening units, (such as BGA solder spheres) as a removable attachment mechanism. This reference, however, does not contemplate the need for improved thermal dissipation of components that are being shielded.
A technique for combining EMI shielding and thermal dissipation is disclosed in U.S. Pat. No. 6,347,035. While recognizing the need to solve both of these problems, the reference teaches only how to accomplish shielding of an entire PCB (e.g. motherboard), which necessarily includes both sides. That is, since the shielding enclosure described is not board-level, the shield cannot isolate sections of the same PCB (on the same side or opposite sides) from each other. References 5,436,803 and 5,597,979 teach similar, bag-like shielding schemes that do not shield at a board-level, and which additionally, do not contemplate the need for thermal dissipation.
Reference 5,175,613 discloses a package that combines EMI, ESD, thermal and mechanical shock protection of circuit chips. Also, reference 6,122,167 discloses an integrated hybrid cooling device with EMI shielding for a portable computer. The shielding schemes in both of these references are not board-level, however, since they do not allow for shielding sections of the same PCB from each other (e.g. one chip from another). Additionally, the solutions require an attachment mechanism involving screws or bolts, and holes that pass through the PCB. This consumes valuable PCB space, as well as adding significant weight to the design.
What has not heretofore been provided, and what is needed, is a board-level shield that is simultaneously removable, compatible with single or multi-compartment designs, thin in profile, lightweight, and allows for thermal dissipation of shielded components.
This invention provides an apparatus having a substrate having at least one electrical component disposed thereon; a plurality of discrete electrically conductive fastening units disposed in a pattern on the substrate surrounding the at least one electrical component; a board-level electromagnetic interference (EMI) shield comprising an electrically conductive layer; a plurality of apertures formed in the board-level EMI shield such that the apertures correspond to the pattern of the electrically conductive fastening units; with at least one thermally conductive interface (TCI) material disposed over the at least one electrical component; and wherein the electrically conductive layer of the board-level EMI shield is in electrical contact with at least one electrically conductive fastening unit.
In another aspect, this invention provides a substrate having at least one electrical component disposed thereon; a plurality of solder spheres disposed on the substrate surrounding the at least one electrical component; a board-level EMI shield comprising at least one compartment adapted to cover the at least one electrical component, the EMI shield further comprising an electrically conductive layer; at least one TCI material disposed over the at least one electrical component; a heat sink disposed over the at least one TCI material; wherein the electrically conductive layer of the board-level EMI shield is in electrical contact with at least one of the solder spheres, and wherein the board-level EMI shield and the solder spheres combine to limit electromagnetic radiation from entering or exiting the at least one compartment; and wherein the heat sink and the at least one TCI material combine to dissipate heat from the at least one electrical component.
In another aspect, this invention provides a board level EMI shield for a substrate having at least one electrical component disposed thereon and a plurality of discrete electrically conductive fastening units disposed in a pattern on the substrate surrounding the at least one electronic component, the board-level EMI shield comprising an electrically conductive layer; a plurality of apertures formed in the board-level EMI shield such that the apertures correspond to the pattern of the electrically conductive fastening units; at least one TCI material attached to the board-level EMI shield; wherein at least one of the apertures has a contact region and wherein the electrically conductive layer of the board-level EMI shield at the contact region of the aperture are deflectable to the extent necessary to allow the contact region to engage and retain at least one of the electrically conductive fastening units; and wherein the electrically conductive layer of the EMI shield at the contact region is adapted to make electrical contact with at least one electrically conductive fastening unit.

Board-level EMI shield with enhanced thermal dissipation


A toner-cartridge-side wireless communication device is attached to a bottom wall of a toner cartridge. A developing-unit-side wireless communication device is attached to an inner position of a toner cartridge mounting portion of a developing unit. The toner-cartridge-side wireless communication device and the developing-unit-side wireless communication device are arranged as opposed to each other, thereby performing stable communication between the toner-cartridge-side wireless communication device and the developing-unit-side wireless communication device.

1. Field of the Invention
The present invention relates to an image forming apparatus for developing an electrostatic latent image, using a magnetic toner.
2. Description of the Related Art
In recent years, there have been known image forming apparatuses constructed in such a manner that an RFID (Radio Frequency Identification) tag is attached to a developing unit, as a developing-unit-side RFID tag, and another RFID tag is attached to a toner cartridge for supplying toner to the developing unit, as a toner-cartridge-side RFID tag to communicate various data between the RFID tags. In the conventional image forming apparatuses, the toner-cartridge-side RFID tag is attached to an upper surface of an upper cover of the toner cartridge, and the developing-unit-side RFID tag is attached to a bottom wall of a toner cartridge mounting portion for mounting the toner cartridge therein.
Japanese Unexamined Patent Publication No. 2003-271042 discloses a wireless communication system constructed in such a manner that an RFID tag is provided in a space between an upper end portion of a cartridge component, and a main body of an image forming apparatus, or a space between a lower end portion of the cartridge component and the apparatus main body; and a main-body-side antenna is provided sufficiently close to an RFID-tag-side antenna to perform desirable communication between the RFID tag as a wireless communication device, and the apparatus main body.
The height of the magnetic toner contained in the toner cartridge is lowered, as the magnetic toner is consumed, and the magnetic toner flies within the space of the toner cartridge, with the result that the toner may adhere to the inner walls or the upper cover of the toner cartridge. As a result, a magnetic field between the toner-cartridge-side RFID tag and the developing-unit-side RFID tag is greatly fluctuated, which obstructs stable communication between the two RFID tags i.e. wireless communication devices. Further, the wireless communication system recited in the above publication is provided to perform desirable communication between the wireless communication device and the apparatus main body, and is not motivated to eliminate a fluctuation of the magnetic field by the magnetic toner.

Image forming apparatus with wireless communication function between toner cartridge and developing unit


An antenna array (e.g., microstrip patch antenna) operates in a manner that exploits the particular susceptibility of the mutual coupling effects between radiating elements in the array. Various differential-mode excitation schemes are provided for determining optimal differential-mode voltages or optimal differential-mode currents that are applied to the radiating elements (e.g., microstrip patches) to thereby achieve certain desirable radiation characteristics including, for example, aiming a radiated beam in a prescribed direction, steering the beam, shaping the radiated beam, and/or optimizing the gain of the antenna in a specified direction.

Microstrip antennas (or patch antennas) provide low-profile antenna configurations for applications that require small size and weight. Such antennas are also desirable when there is a need to conform to the shape of the supporting structure, both planar and nonplanar, such as for an aircraft's aerodynamic profile. These antennas are simple and inexpensive to manufacture using printed-circuit technology, wherein metallic patches (or patch radiators) are typically photoetched onto a dielectric substrate.
The conventional wisdom regarding microwave patch antennas is that the patches radiate from their edges. More specifically, when the elements of a patch antenna array are excited in common mode (i.e., with equal voltages), the fields that are generated are primarily confined to the dielectric space under each surface element, except for the fringing fields at the edges of the elements. The commonly held view of the mechanism of radiation by patch antennas is that it is the fringing fields at the edges that radiate into the air. Indeed, various models and theoretical analyses have been developed to explain this radiation mechanism, such as the slot radiation model (see, e.g., R. E. Munson, "Conformal microstrip antennas and microstrip phase arrays," IEEE Trans. Antennas Propagat., vol. 22, pp 74-78. January, 1974) or the cavity model (see, e.g., Thouroude et al, "CAD-oriented cavity model for rectangular patches," Elect. Lett., vol. 26. pp. 842-844, June 1990). Both the slot and cavity models assume radiation comes only from the edges. Other models known to those skilled in the art, including, for example, conformal mapping, moment methods, and Green's functions, have been developed, which implicitly include fields that are not at the edges. However, these methods offer limited insight into the radiation mechanism.
FIG. 1 illustrates a typical patch antenna array 10 that comprises small conducting surfaces 18 separated from a large parallel ground plane 14 by a dielectric substrate 16. When the same real or complex (real and imaginary or amplitude and phase) RF voltage V0 is applied to each surface 18, an electric field pattern 15 is set up in the dielectric, essentially acting as a capacitor but with a relatively weak fringing fields 12 at the edges (for clarity, fields 12 are not shown continuing into the substrate). The roughly uniform fields 15 under the surface are fairly well shielded from the outside space, but the fringing field at the edges can act as radiating elements. To take advantage of the edge radiators, it may be necessary to excite the capacitive structure in a higher-order mode and using off-center feeds, to avoid mutual cancellation of the radiation from different edges.
Microstrip patch antennas commonly exhibit disadvantageous operational characteristics such as low efficiency, low power, narrow bandwidth, and poor scanning performance. Further, patch antennas are typically excited in an asymmetric manner to generate high-order modes of the dielectric substrate, which adds to the complexity of the electrical feed circuitry.
A natural phenomenon referred to as "mutual coupling" occurs when the patches of an antenna array are subjected to differential-mode excitation (e.g., different voltage amplitudes and phases). In particular, when the applied voltages at two or more patches are different, fields will be set up not only within the substrate directly under each patch, but also in the air space above the patches, emanating from one patch and ending on another.
Conventionally, designers of patch antennas ignore or attempt to reduce the effects of mutual coupling. However, it would be highly beneficial to develop a framework for differential-mode excitation of an antenna array that would exploit the mutual coupling between patches to provide efficient radiation from the exposed top surfaces of antenna patches to, thereby, overcome the above noted deficiencies and disadvantages of conventional patch antenna schemes.

Systems and methods for providing optimized patch antenna excitation for mutually coupled patches

The Trustees of Columbia University in the City of New York


A softstarter for starting and stopping an asynchronous motor having three phases, including two pairs of semiconductor devices of the type turning off at zero-crossing of the current therethrough, wherein each of the two pairs of semiconductor devices is connected in anti-parallel, and the first pair of the semiconductor devices is adapted to control the voltage of one of the phases of the motor and the second pair of the semiconductor devices being adapted to control the voltage of another of the phases of the motor, a DC reducing unit associated with the two pairs of semiconductor devices, a first voltage measuring unit for measuring voltages across the two pairs of semiconductor devices, and a first zero-crossing detecting unit configured for detecting zero-crossings of the measured voltages across the two pairs of semiconductor devices and providing zero-crossing signals to the DC reducing unit.

A softstarter for an asynchronous three-phase motor, comprising semiconductor devices for controlling voltages applied to the motor in one, two or three of the phases by adjusting firing angles of semiconductor devices of the type turning-off at zero-crossing of the current therethrough, wherein two semiconductor devices connected in anti-parallel with each other in each phase, has been used for some time. By controlling the voltage in the respective phase a reduction of the torque and current provided to the motor is achieved during start and stop operation. The firing angle of the semiconductor devices is used for controlling the amount of energy supplied to the motor.
Each of these types of softstarters is normally provided with three such pairs of semiconductor devices, such as thyristors. However, the semiconductor devices have become a cost-determining factor of such a softstarter, so a softstarter having only two pairs of such semiconductor devices for three of the phases is used for controlling the voltage applied to three-phase motors. This means that the remaining third phase is in the form of a conductor, which cannot be switched. The present invention is related to this type of softstarters.
It is desired that a softstarter with the above-mentioned type is able to start and stop motors in a desired torque ramp in order to minimize electrical surges in the electrical supply and/or overheating in the motors and to reduce mechanical shocks or vibration which might otherwise occur under start/stop conditions causing wear and damage to the pumps, fans etc. driven by the motors. Such damage may result in higher maintenance costs and also a shortening of the lifetime on the pipe-system.
However, when the control is limited to only two phases, undesired effects in the form of, for example, a DC component in the motor current appear during starting and stopping operation. During start-up or shut-down operation a smooth and gradually increasing or decreasing torque is desired, but this DC component appearing during start-up or shut-down sometimes generates a braking or oscillating torque. This can be both disturbing and damaging to the controller system, the electric motor, and to the motor driven load.
Furthermore, it is costly to carry out measurements on the third phase that is in the form of a conductor since an extra measuring unit and connection point have to be built only for the purpose of the measurement.
A patent application, with a publication number WO 2008/033088, describes a method and a softstarter for reducing such a DC component during start and stop of a motor having three phases, only two of the three phases being controlled by two pairs of semiconductor devices, wherein firing angles of the semiconductor devices are adjusted at a zero-crossing of the current that flows through the semiconductor devices. However, this invention may still have some error in the timing when triggering the semiconductor devices, so that DC components can not be reduced efficiently.
A patent application, with a publication number WO 2008/046885, describes a control method and motor starter device, wherein a motor has three phases and each of the three phases is controlled by a pair of semiconductor devices and the motor torque is controlled in dependence on a torque error signal, based on the calculated difference between the motor torque and a reference torque value, so that the motor torque displays a rate of change with respect to time, during a stopping or starting time interval. However, this invention is related to a softstarter comprising three pairs of semiconductor devices, each pair controlling each of the three phases of the motor.

Softstarter for controlling an asynchronous three-phase motor


An approach is provided for reusing a cleaning web to clean portions of a fuser unit. The approach involves causing a cleaning web supply mechanism to feed a cleaning web having a first surface and a second surface to the portions of the fuser unit. The approach also involves causing a cleaning web receiving mechanism to receive the cleaning web following a cleaning process in which the first surface of the cleaning web is used to clean at least one of the portions of the fuser unit. The approach further involves causing the cleaning web receiving mechanism to return the cleaning web to the portions of the fuser unit to clean at least one of the portions of the fuser unit using the second surface of the cleaning web.

Conventional fuser units require cleaning and often use a cleaning web made of a fabric or polymer, for example, that can be costly. In conventional fuser units, the cleaning web is used to clean various portions of the fuser unit. For example, the cleaning web in conventional fuser units has two surfaces and is pressed against one or more portions of the fuser unit such as an external heat roll to clean off toner and various contaminants. The cleaning web is often supplied to the fuser unit such that only one surface of the two surfaces of the cleaning web performs the cleaning. After use, the cleaning web must be replaced because the surface of the cleaning web that performs the cleaning is soiled with toner and other contaminants.

Method an apparatus for reusing a cleaning web to clean a fuser unit


A reflection-type polarizer according to the present invention has an improved bright line visibility phenomenon and a wider viewing angle, compared with a conventional dispersion-type reflection polarizer, and can maximize luminance improvement while minimizing optical loss. In addition, in connection with implementing a reflection polarizer, a group dispersion body can be formed through simple control, making it possible to maximize productivity improvement through process simplification.

Flat panel display technology mainly features a liquid crystal display (LCD), a projection display and a plasma display panel (PDP), which have captured the market in the field of TVs, and with the improvement in related technology, a field emission display (FED), an electroluminescent display (ELD), etc. are expected to occupy fields per characteristic. Today, the range of LCDs has expanded into a notebook, a personal computer monitor, a liquid crystal TV, an automobile, an airplane, etc., and LCDs account for approximately 80% of the flat panel market, and are globally booming currently because of a rapid increase in demand.
In a conventional LCD, liquid crystals and an electrode matrix are placed between a pair of absorptive optical films. In the LCD, the liquid crystal part is moved by an electrical field generated by applying a voltage to two electrodes, and has an optical state changed thereby. Such treatment enables "pixels" carrying information to display an image using polarized light in a specific direction. Because of this, the LCD includes a top-side optical film and a bottom-side optical film, inducing polarization.
In an optical film used in the LCD, efficiency of light utilization emitted from a backlight is not necessarily high. This is because 50% or more of light emitted from the backlight is absorbed by a bottom-side optical film (absorptive polarizing film). Therefore, to increase the light-use efficiency of the backlight in the LCD, a reflective polarizer is installed between an optical cavity and a liquid crystal assembly.
FIG. 1 is a diagram illustrating an optical principle of a conventional reflective polarizer. In detail, p-polarized light of light moving from an optical cavity to a liquid crystal assembly is set to be transferred to the liquid crystal assembly by passing through a reflective polarizer, and s-polarized light emitted from a reflective polarizer is reflected to the optical cavity, reflected on a diffusing reflective surface of the optical cavity while polarization direction of light is randomized, and then is sent back to the reflective polarizer, resulting in conversion into the p-polarized light that can pass through the polarizer of the liquid crystal assembly. Then, the p-polarized light is transferred to the liquid crystal assembly through the reflective polarizer.
Selective reflection of the s-polarized light and transmission of the p-polarized light for incident light of the reflective polarizer are achieved by a difference in refractive index between optical layers while one planar optical layer having an anisotropic refractive index and the other planar optical layer having an isotropic refractive index are mutually and alternately stacked, setting of optical thicknesses of the optical layers according to elongation of the stacked optical layers, and a change in refractive indexes of the optical layers.
That is, as light incident to the reflective polarizer passes through the optical layers, the reflection of the s-polarized light and the transmission of the p-polarized light are repeated, and therefore only the p-polarized light of the incident polarized light is transferred to the liquid crystal assembly. Meanwhile, the reflected s-polarized light is, as described above, reflected while a polarization state is randomized at the diffusing reflective surface of the optical cavity, and then is sent back to the reflective polarizer. Therefore, power waste as well as the loss of light generated from a light source may be reduced.
However, since such a conventional reflective polarizer was manufactured to have an optical thickness and a refractive index between the optical layers that enabled optimization for the selective reflection and transmission of the incident polarized light by alternately stacking planar isotropic optical layer and anisotropic optical layer, which had different refractive indexes, and elongating these optical layers, a process of manufacturing the reflective polarizer was complicated. Specifically, since, due to the planar structure of the optical layer of the reflective polarizer, the p-polarized light had to be separated from the s-polarized light, corresponding to a wide range of an incidence angle of the incident polarized light, the number of stacked optical layers was increased so much that a production cost was exponentially increased. Also, because of a structure in which the optical layers are excessively stacked, optical performance was degraded by optical loss.
FIG. 2 is a cross-sectional view of a conventional multilayer reflective polarizer (DBEF). In detail, the multilayer reflective polarizer has skin layers 9 and 10, which are formed on both surfaces of a base 8. The base 8 is divided into four groups 1, 2, 3 and 4, each group including approximately 200 layers by alternately stacking isotropic layers and anisotropic layers. Meanwhile, separate adhesive layers 5, 6 and 7 are formed between the four groups 1, 2, 3 and 4 forming the base 8 to bond them. Also, since each group has a very small thickness of more or less 200 layers, when these groups are individually coextruded, the groups may be damaged, and therefore probably have a protective layer (PBL) in many cases. In this case, the base became thicker, and a production cost was increased. Also, since a reflective polarizer included in a display panel has a limited base thickness for slimming, when an adhesive layer is formed on a base and/or a skin layer, the base is reduced by the thickness of the adhesive layer, and therefore there was a serious problem for improvement of optical properties. Furthermore, since the inside of the base, the base and the skin layer are bonded by the adhesive layer, an interlayer peeling phenomenon may be generated by an external force, long periods of time elapsed or a poor storage area. There also was a problem of an excessively high defect rate in the attachment of the adhesive layer, and destructive interference to a light source due to the formation of the adhesive layer.
When the skin layers 9 and 10 are formed on both surfaces of the base 8, separate adhesive layers 11 and 12 are formed between the base 8 and the skin layers 9 and 10 to bond them. When a conventional polycarbonate-based skin layer is integrated with a PEN-coPEN alternately-stacked base by coextrusion, peeling may occur due to the loss of compatibility, the risk of birefringence with respect to an elongation axis in an elongation process is high since a crystallization degree is within 15%. Accordingly, to apply a polycarbonate sheet for a non-elongation process, an adhesive layer had to be formed. As a result, due to the additional adhesive layer process, a yield is reduced by external impurities and process defects, and usually, to produce a non-elongated polycarbonate sheet of the skin layer, birefringence is caused by non-uniform shear stress generated in a winding process. For this reason, separate controls such as transformation of the molecular structure of a polymer and control of the velocity of an extrusion line are required, and thus productivity is degraded.
Simply describing a method of manufacturing the conventional multilayer reflective polarizer, four groups having different average optical thicknesses enabling formation of the base are separately coextruded, subjected to elongation, and bonded with an adhesive, resulting in manufacturing a base. This is because peeling is generated by elongating the base after the bonding with the adhesive. Afterward, a skin layer is bonded to both surfaces of the base. To form a multilayer structure, one group (209 layers) has to be formed in a process of forming a multilayer structure including forming a tetralayer structure by folding a bilayer structure, continuously folding the structure, and coextruding the resultant structure. Therefore, it was difficult to form a group in the multilayer structure using one process without a thickness change. As a result, after separate coextrusion, the four groups having different average optical thicknesses had to be bonded.
Since the above-described process was intermittently performed, it led to a considerable increase in production costs, and thus among all of the optical films included in a backlight unit, the resultant multilayer polarizer had the highest cost. Therefore, for the sake of cost reduction, there were serious problems of frequently introducing an LCD excluding a reflective polarizer even when the reduction in luminance was ensured.
Therefore, a reflective polarizer, not a multilayer reflective polarizer, in which dispersed bodies capable of achieving the function of a reflective polymerizer, by aligning birefringent polymers elongated in a lengthwise direction in a base, are dispersed has been suggested. FIG. 3 is a perspective view of a reflective polarizer 20 including rod-shaped polymers, in which birefringent polymers 22 elongated in a lengthwise direction in a base 21 are aligned in one direction. Accordingly, a light modulating effect is caused at a birefringent interface between the base 21 and a birefringent polymer 22 to perform the function of the reflective polarizer. However, compared with the above-described alternately-stacked reflective polarizer, it was difficult to reflect light over the entire visible wavelength range, and thus light modulation efficiency was overly decreased. Thus, to have transmittance and reflectivity similar to those of the alternately-stacked reflective polarizer, an excessive number of birefringent polymers 22 had to be disposed in the base. In detail, to manufacture a 32-inch wide display panel based on the vertical cross-section of the reflective polarizer, at least 1×108 round or elliptical birefringent polymers 22 having the lengthwise cross-sectional diameter of 0.1 to 0.3 μm have to be included in a base 21 having a width of 1580 mm and a height (thickness) of 400 μm or less to have optical properties similar to those of the above-described stack-type reflective polarizer. In this case, there were difficult problems in which the reflective polarizer had an excessive production cost and was manufactured by overly complicated equipment in a production facility, thus making it nearly impossible to be commercialized. Also, since it is difficult to form a birefringent polymer 22 included in the sheet with various optical thicknesses, it is difficult to reflect light over the entire visible range, and thus physical properties are degraded.
To overcome these obstacles, a technical idea including a base having a birefringent islands-in-the-sea fiber has been suggested. FIG. 4 is a cross-sectional view of the birefringent islands-in-the-sea fiber included in the base. Since the birefringent islands-in-the-sea fiber may have a light modulating effect generated at a light modulating interface between an island and a sea therein, even though a very large number of islands-in-the-sea fibers are not disposed, like the above-described birefringent polymer, optical properties may be achieved. However, the birefringent islands-in-the-sea fibers are fibers, and thus have problems of compatibility, handleability and cohesion with the base, which is a polymer. Further, as reflective polarization efficiency for an optical wavelength in the visible range is reduced by induction of light scattering because of a round shape, compared with the conventional products, the reflective polarizer has poor polarization characteristics and thus has a limitation in luminance improvement. In addition, in the islands-in-the-sea fibers, since pores were generated by the reduction of an island coupling phenomenon and the subdivision of a sea component region, the optical characteristics were degraded due to light leakage, that is, optical loss. Also, an organizational form of the fabric had a limitation in improvement in reflection and polarization characteristics because of the limitation of a layered configuration. Moreover, a dispersion-type reflective polarizer had a problem of bright line visibility because of the gap between layers and the space between dispersed bodies.

Random dispersion-type reflection polarizer


A PIN photodiode comprising a P-type layer, an N-type layer, and an I-type layer provided between said, P-type layer and said N-type layer, wherein a junction surface between said I-type layer and said N-type layer is formed by joining a high specific resistance wafer preformed as said I-type layer to a high concentration N-type wafer preformed as said N-type layer. The thickness of said high specific resistance wafer has been adjusted in accordance with the peak value of the wavelength of light rays to be accepted. Therefore, N.sup.+ carriers do not exist in the I-type layer and the thickness of the I-type layer can be freely defined, causing the frequency characteristic and the wavelength sensitivity characteristic to be satisfying.

1. Field of the Invention
The present invention relates to a PIN photodiode used as a receiving element for converting a light wave to an electric signal in an optical communication, more particularly relates to improvements in characteristics such as a frequency characteristic or a wavelength sensitivity characteristic.
2. Background Art
Examples of conventional PIN photodiodes are shown in FIGS. 4 and 7. A high concentration N-type layer (an N.sup.30 layer) 91 in a PIN photodiode 90 shown in FIG. 4(A) is formed by a diffusion from one surface of a high specific resistance silicon wafer 92A. The thickness of an I-type layer 92 as a remaining part is determined by the control of the diffusion. Further, a high concentration P-type layer (a P.sup.30 layer) 93 is formed by a diffusion from the opposite surface to the N-type layer 91, thereby forming the basic constitution of a PIN photodiode 90.
Since the high concentration N-type layer (an N.sup.+ layer) 91 is formed by the diffusion as described, some N.sup.+ carriers (hereinafter referred to as "N carriers") are diffused into the I-type layer 92. The concentration distribution B1 of the N carriers in the N-type layer 91 and the I-type layer 92 will have a gentle slope as shown in FIG. 4(B). This means a depletion layer 94 is a shallow layer which does not reach a junction surface 95 between the N-type layer 91 and the I-type layer 92.
An I-type layer 82 in a PIN photodiode 80 shown in FIG. 7(A) is formed by an epitaxial growth on one surface of a high concentration N-type wafer 81A as shown in FIG. 8. In this conventional art, the thickness of the I-type layer 82 is determined by, for example, a time control of the epitaxial growth. Further, a P-type layer 83 is formed as well as the above-described conventional art.
Since the I-type layer 82 is formed by the epitaxial growth on the preformed N-type layer (the N.sup.+ layer) 81, it is possible to form the I-type layer 82 which does not contain so many N carriers. The concentration distribution B2 of the N carriers in the N-type layer 81 and the I-type layer 82 will have a step-like shape as shown in FIG. 7(B). This means a depletion layer 84 substantially reaches a junction surface 85 between the N-type layer 81 and the I-type layer 82.
However, there are some problems with regard to the PIN photodiodes 80 and 90 as following. As for the photodiode 90, although there is an advantage that the wavelength sensitivity of light rays depending on the thickness of the I-type layer 92 can be easily defined due to the easiness for controlling the thickness of the I-type layer 92, there is a problem that it can not deal with optical communication requiring a high-speed characteristic due to the shallowness of the depletion layer 94 which leads a response frequency characteristic F1 to be 10 MHz at most as shown in FIG. 6.
As for the photodiode 80, the depletion layer 84 substantially reaches the junction surface 85 of the N-type layer 81 and the I-type layer 82, and therefore about 200 MHz of a response frequency characteristic F2 can be obtained as shown in FIG. 9. However, it is substantially impossible to form a thick I-type layer with a thickness of, for example, at least 30 .mu.m (preferably at least 40 .mu.m) by the epitaxial growth, which causes the peak value of wavelength sensitivity to be shifted to a short wavelength side. This makes a problem that the peak value can not be conformed to the oscillating wavelength of a semiconductor laser which is practically used.
In addition, since the epitaxial growth process by which the I-type layer 82 in the photodiode 80 is formed is a difficult process, it takes too much time for forming the I-type layer 82 even if the thickness of the I-type layer 82 is restricted to, for example, 20 .mu.m, and leads the PIN photodiode 80 to a low yield, which in turn raises the cost of the PIN diode 80.


Embodiments of the invention enable data to be moved from one or more external sources into a database system. A plurality of processes are executed concurrently. Each of the processes are executable to move data from at least a portion of the one or more external sources into the database system, so that executing the plurality of processes concurrently moves data from different portions of the one or more external sources into the database system in parallel. Execution of the plurality of processes are coordinated from the database system.

Warehouses are central databases that can be used to store data from many other data sources. A warehouse may store data from other databases, servers, work stations, storage disks or other storage mediums. The warehouse provides a central location for operators and users to analyze data that would otherwise be scattered across multiple, discrete storage mediums. For example, a warehouse enables operators and users to study historical data for purpose of running business logic or models. The historical data may have, at one time, been recorded on individual computer machines that could not easily share large amounts of stored information with one another.
Extraction, transformation and loading (ETL) procedures are used to move data from scattered sources into a target warehouse. Typically, ETL operations are performed externally to the target warehouse. The extraction procedure is executed to retrieve data from one or more data sources. The transformation procedure is used to alter the extracted data, and may involve performing operations, conversions and/or other functions on the data. The loading process is used to move the transformed data into the target warehouse.
Current systems implement ETL operations in tools that are external to the target warehouse. Vendors that provide tools to perform ETL operations are often different than those who provide the warehouse.
FIG. 6 illustrates a system 1000 for moving data from scattered data sources into a target database system. The system 1000 includes components for performing ETL operations. The system 1000 typically includes a target database system 1020, and an intermediate tool 1030. The system 1000 is used to move data from data sources 1010 into target database system 1020. The tool 1030, which resides on a computer system 1040, is external to the target database system 1020. The computer system 1040 and database system 1020 may be different machines.
Based on input from a user, the tool 1030 identifies data that is to be moved from data sources 1010. The identified data is moved using a transport mechanism. The identified data may be moved to computer system 1040, where it is staged. The tool 1030 then performs one or more transformation functions T(x) on the data collected from data sources 1010. The transformed data is staged again in computer system 1040. After being staged, the transformed data is then loaded into target database system 1020.
Some variations to the traditional ETL technique exist. In one variation, intermediate steps such as staging, may be performed within the target database system 1020. This may involve moving data directly from the data sources 1010 into target database system 1020. The tool 1030 may access the data from the target database system 1020 in order to perform one or more transformations on the data. The transformed data is then loaded into one or more final destinations within the target database system 1020. This allows the tool 1030 to use the target database 1020 as an intermediate staging area.
The use of external tools for performing ETL operations requires interoperability considerations between target database system 1020 and tool 1030. For example, tool 1030 may be provided by one vendor, and target database system 1020 may be provided by another vendor. Providing interoperability may be costly, may require custom programming, and may be prone to error.
In addition, repeated staging of extracted data may be required in order to convert the extracted data into a database format for target database system 1020. It is possible for existing systems to move data from data sources 1020 into the target database 1010 without externally staging the data. In one system, tool 1030 moves raw data from multiple data sources 1010 into target database system 1020. The raw data is staged internally in the target database system 1020. After the data is staged, the user may instruct the database to perform one or more transformations on the data. The database system then integrates the transformed data into a table data structure.
In this kind of system, the target database 1020 typically interacts with an external engine in order to perform one or more steps of moving, transforming and storing the data. Steps for performing transformation and integration of the collected data are usually specified by the instructions provided by the user. The user may send remote procedure calls (RPCs) to invoke routines for performing specific transformation operations. The routines thus invoked may also cause the extracted data to be loaded into the target database system 1020 from the staging area.
Often, each transformation performed on the collected data requires the output of the transformation to be staged. If multiple transformations are required, repeated staging of the collected data is required. The data may also need to be staged prior to being stored in the target database system 1020. Repeated staging of the data collected from the data sources 1010 takes up a significant amount of the target database system's resources.
Many existing systems that perform ETL operations generally do not provide for parallel transfer of data into the target database system. Rather, such systems load data into the target database system sequentially or serially. For example, the process of loading one or more external tables into the target database system may be achieved by sequentially transferring data from each table in a row-wise fashion. As a result, the time to perform ETL operations is directly dependent on the size of the data being transferred in.
Some database systems are able to receive external data in parallel during ETL operations. In such scenarios, the external data is typically "pushed" into the target database system from multiple external data sources. Usually, an external ETL tool (such as shown by numeral 630 in FIG. 6) or clients of the target database system initiate the request to load the data in parallel. The external data is loaded into the target database system through the control of some system that is external to the target database system, such as by the external ETL tool.
When systems external to the target database system load external data into the target database system in parallel during ETL operations, the target database system is not able to coordinate the transfer of data that it receives. As a result, some problems may arise. For example, multiple data items received from external sources in parallel may be designated for the same internal location within a database of the target database system. Some current database systems use temporary storage to address such contention among data items being loaded into the target database system. But temporary storage of data during ETL operations can cause fragmentation of the data being transferred into the target database system.
Furthermore, the mechanism(s) used in current ETL systems to load data in parallel into the target database system may transfer some portions of the external data faster than other portions. As a result, queues may form where one portion of the overall external data is loaded into the target database system slower than other portions. If different mechanisms or processes are used to load data into the target database system, then the slower mechanism or process can reduce the efficiency of the parallel loading process for all of the external data.

Parallel transfer of data from one or more external sources into a database system


There is disclosed systems and processes for optimizing circuit descriptions by reducing clock skew, re-organizing and/or converting gated and generated clock circuits, and reconnecting clock nets and other related nets. A transformed circuit design may be produced from an initial circuit design and having a reduced number of secondary clocks and a reduced amount of clock skew.

1. Field of the Invention
The present invention relates to clocked circuits.
2. Description of the Related Art
Synchronous sequential circuits rely on their clock signals for reliable operations. Clocked sequential elements such as flip-flops or registers transfer input data to output data at the transition of the clock signal. For proper loading, the input data have to meet the set-up and hold time requirements. Since these critical timing parameters are determined with respect to the clock signal, any clock skew or delay may cause timing violations, resulting in erroneous data loading. Delay is an amount of time by which a signal is retarded from a first point to a second point. Skew is a measure of divergence of the delay of a signal into two circuits. Clock skew is typically due to two causes. The first is uncontrolled differences in material and topology of the clock net. The second is the amount of delay introduced by the circuitry that generates a derived clock from a parent clock. Ideal clock delay and ideal clock skew are zero, and non-zero delay and skew typically must be compensated for. Clock skews and delays may also limit the operating frequency range, leading to degraded performance.
There are several sources that may cause clock skew in sequential circuits. One of the major sources is the use of gating circuitry to selectively enable or disable the clock signal. A typical gating circuitry may involve several levels of gating circuits, often in the form of AND or OR gates. These gates may introduce undesirable delays and cause unpredictable timing problems.
Routing is one source of delay. The problem is even more pronounced when circuits are prototyped in programmable devices such as field programmable logic arrays (FPGAs). In these programmable logic devices, the gated clock signals are typically routed on the general routing network due to the limited number of available dedicated clock routing networks. The general routing network usually introduces significant and unequal delays in the distribution of clocking signals to various sequential elements, causing clock skews at the clock inputs of the sequential elements.
One technique to reduce clock skew is to use delay elements at various points in the clock signal paths to compensate for the unequal delays. This technique increases the amount of hardware and circuit complexity. In addition, the delay elements may have their own delay variations which may not compensate well. Finally, this technique is typically not applicable in FPGAs.


Methods and systems for delivering audio content to a headset are disclosed. A user taps a close proximity data exchange headset onto an device to download audio content. The audio content is played at the headset. In another embodiment, a user can record audio content with a headset and save the content onto a close proximity data exchange device. Other parties may then use the close proximity data exchange device to retrieve the audio content. Security techniques could be implemented to ensure only an authorized person can store or retrieve audio content. The close proximity data exchange headset may be a near field communication (NFC) headset, and the close proximity data exchange device may be an NFC device.

Near field communication (NFC) allows devices to establish contactless communication by a near field communication interaction such as "tapping" or "waving" the devices together, bringing the devices into close proximity (within a few centimeters). Communication is via inductive coupling of a magnetic field between a first NFC device and a second NFC device. NFC-enabled devices have become increasingly popular due to their convenience and ease of use, particularly with portable devices such as mobile phones and smartcards. NFC technology has been utilized in many day-to-day transactions including e-ticketing, financial exchanges, and media content distribution.


A laminate article preferably including two or more layers adapted to be applied to a surface of a roadway that can function as a reflective marker, such as a lane marker or road feature marker. The article includes one or more reflective compounds, preferably particles, aggregates, or clusters that are partially embedded in an exposed outer surface layer of the article. In order to increase the durability of the material, protective media compounds are also present in the outer layer and extend outward therefrom with the protective material protruding a greater distance than the reflective compounds. The articles of the present invention are weather resistant, durable and resistant to damage by vehicles and snowplows.

Roadway markers are used on or around roads to convey or display information, such as pavement markings, traffic lanes, road stripes or delineators, etc. Oftentimes, roadway markers include a reflective component so that motor vehicle drivers can clearly see the markers after dark. Reflective roadway markers have the ability to reflect some portion of incident light back towards the source from which the light originated. Motor vehicle headlamps are turned toward the road surface to illuminate, for example, the boundaries of traffic lanes for the motor vehicle driver.
It is known that roadway markers used on a road are subject to wear caused by traffic and other conditions. One manner in which roadway markers become damaged is by the wear caused by snowplow blades. Snowplow blades are designed to clear the roadway of snow and ice and, therefore, preferably continually engage the surface of the road. When a snowplow blade contacts a roadway marker, the blade can impact the marker and components thereof, such as reflective compounds, with sufficient force to break off some of the compounds or portions of the marker and also from the roadway. After a period of time, a sufficient number of reflective compounds can wear off so that reflectance provided by the roadway marker is significantly diminished.
Numerous different approaches have been attempted to provide roadway markers, some with the goal of preventing or minimizing impact by a snowplow blade or reduce wear from the tires of an automobile. Some of the approaches are described for example in U.S. Pat. Nos. 2,897,732; 3,030,870; 3,204,537; 4,758,469; 5,380,549; 5,660,497; 5,676,488; 5,759,928; 5,763,000; 5,782,577; 6,225,371; 6,247,818; 6,431,788; and 7,168,815.
For example, U.S. Pat. No. 6,431,788 relates to pavement marking and methods of making pavement markings in which the pavement markings reportedly exhibit wear resistance to, e.g., snowplow blades. The pavement markings include elongated protuberances in which successive elongated protuberances overlap along at least the longitudinal direction and may also overlap in a direction transverse to the longitudinal axis. Other protuberances are interspersed between the elongated protuberances to reportedly improve retro-reflectivity. The elongated protuberances are provided to reportedly support, e.g., a snowplow blade moving over the pavement marking.
In view of the prior art, there is still a need for an improved method for protecting roadway markers disposed on roadways from wear, such as from forces due to snowplow blades.

Wear and impact resistant reflective road lane markers


A system and method for perforating and gravel packing a wellbore casing in a single trip into the wellbore comprising a gravel packer assembly having a production screen and at least one packer. A perforating apparatus connected to the gravel packer assembly, wherein the perforating apparatus is detachable from the gravel packer assembly after the system is placed in the wellbore and before a detonation of the perforating apparatus. A tool having at least one casing engaging slip segment, wherein the tool is matable with the perforating apparatus and is settable in the wellbore casing.

The present invention relates to apparatuses and methods for the completion of mineral production wells. In particular, the invention is related to a perforating and gravel packing system and method.
Modern oil and gas wells are typically equipped with a protective casing which is run into the wellbore. Production tubing is then run into the casing for producing minerals from the well. Adjacent the production zones, the protective casing is perforated to allow production fluids to enter the casing bore. Since particles of sand are typically carried with the mineral from the production zone into the casing, it is sometimes necessary to install a gravel pack or production screen to filter the particles of sand. Therefore, it is common practice to complete a mineral well in two steps: (1) run-in the well with a perforating gun to perforate the casing; and (2) run-in the well with a gravel pack tool to gravel pack and/or isolate the perforated zone. However, this method is disadvantageous because it requires multiple trips into the well to perforate and gravel pack the zone.
To reduce the required number of trips into the wellbore casing, various single trip perforation/gravel packing devices have been developed. For example, as described in U.S. Pat. No. 4,372,384, incorporated herein by reference, a single trip apparatus for completing a formation in a case borehole is disclosed. The patent teaches the use of a tool string which includes a perforating gun, gravel packing tools and a packer means. The casing is perforated by running a gun firing device down through the tubing string. The well is allowed to flow freely to clean up the perforated formation. The system is then moved to position a sandscreen of the gravel packer adjacent the perforations and packers are used at each end of the screen to straddle and pack off the perforated pay zone. With the screen and packers in position, a gravel pack is established in the annulus between the perforated casing and the screen. The tool screen is left downhole in the casing as a permanent completion device. The produced fluid is allowed to flow through the perforations, the gravel, screen, and finally up through the tubing screen to the surface.
An alternative well completion system is disclosed in U.S. Pat. No. 5,954,133, incorporated herein by reference. In particular, a method of displacing a perforating gun in a well bore is used to perforate multiple zones without the need to unset or reset a packer. Multiple perforating guns in a positioning device are configured in an axially compressed configuration. The perforating guns are attached to the positioning device and inserted into the wellbore. With a first perforating gun positioned adjacent a first zone, the gun is fired to perforate the casing. The positioning device is then extended to axially displace a second perforating gun within the casing to a position adjacent a second zone. The second gun is then fired to perforate the casing. After a zone(s) has been perforated, the positioning device is further axially extended to displace a production screen and packer. The production screen is positioned adjacent the perforations and the packer is positioned opposite the perforations.
As illustrated in the above referenced patent documents, in traditional one-trip systems, the perforating gun assembly is mechanically connected to the gravel pack assembly during run-in and perforating operations. A basic problem with traditional one-trip perforation/gravel packing systems is that the gravel packing portions of the system are damaged when the guns of the perforation portion of the system are detonated. In particular, a major factor affecting the reliability of one-trip perforation/gravel packing systems is the effects of gunshock on the gravel pack assembly. This shock loading can be in the form of a mechanical force which is communicated through a pipe string or similar structure correcting the perforating guns to the gravel packing assembly. Alternatively, a pressure wave created during detonation in the fluid column inside the wellbore casing can damage the gravel packing apparatus due to a shock effect It has been very difficult to predict the size of this shock effect and even more difficult to prevent it.
Therefore, there is a need for a one-trip perforation/gravel packing system which is more reliable than traditional systems in that the gravel packing portion of the system is protected from gunshock generated by the guns of the perforating portion of the system.

Separable one-trip perforation and gravel pack system and method


In an example embodiment, there is disclosed an apparatus comprising an audio interface configured to receive an audio signal, a data interface is configured to communicate with at least one social graph, and logic is coupled to the audio interface and the data interface. The logic is configured to identify a calling party. The logic is further configured to acquire data representative of a called party from the audio signal. The logic is configured to initiate a search of the at least one social graph for the data representative of the called party to identify the called party responsive to acquiring the data representative of the called party.

Directories and phonebooks enable users to conveniently locate names and contact information. However, as phonebooks and directories grow larger in size, locating names becomes more time consuming and less convenient. Voice recognition technology has been developed and widely used in the industry to allow users to access and retrieve names from a phonebook or directory more conveniently by speaking a name. The voice recognition technology translates the spoken name to text and uses the text to retrieve the name from the directory.
When audio quality in a voice network is poor, however, results returned by the voice recognition technology may be inaccurate or confusing. Additionally, the results may be inaccurate or confusing if a user has a heavy accent. Spoken relationships, as opposed to spoken names, may also produce inaccurate or confusing results.

Method and system for speech recognition using social networks