An external device that is electrically connected to a main unit by a plurality of electric cables includes a first casing member storing a function unit; an external cover covering the first casing member; and a first space provided between the first casing member and the external cover. The electric cables are pulled out of the first casing member, bundled together, supported by the first casing member, and extended out of the external cover through the first space.

1. Field of the Invention
The present invention relates to a technology for attaching an external device to a main apparatus using an electric cable.
2. Description of the Related Art
In an electronic apparatus such as an image forming apparatus, an optional device is typically attached to a main unit for enhancing functions of the main unit. For example, a composite machine is an image forming apparatus that has functions of a copier, a printer, and a fax machine. A composite machine shown in FIGS. 15A and 15B includes an image reading unit 2 (optional device) mounted on an imaging device 1 (main unit). An operation section 3 protrudes from the front side of the image reading unit 2. A reading unit of the image reading unit 2 is located in a casing member 4, and the casing member 4 is covered by an external cover 5.
Electric cables 6a, 6b, 6c extend out from the reading unit, pass through a space 7 between the casing member 4 and the external cover 5, and connect to the imaging device 1, in such a manner not to cross over each other. As shown in FIG. 16, the electric cables 6a, 6b, 6c are electrically connected to electrical substrates a, b, c in the imaging device 1, respectively.
Different optional devices can be provided according to a user's requirement. For example, when a user orders a composite machine, the imaging device 1 and the image reading unit 2 are provided. When a user orders a printer, only the imaging device 1 is provided, and when a user orders a fax machine or a copier, the imaging device 1, the image reading unit 2, and a corresponding circuit board are provided.
The main unit and the optional device are not always provided integrally. According to a user's requirement, the optional device can be an external device that is attached to the main unit with electric cables, and located separately.
For example, as shown in FIG. 17, the image reading unit 2 is placed on a table 8, and is electrically connected to the imaging device 1 with electric cables 6d, 6e, and 6f. Accordingly, the operation section 3 is situated at a lower level as compared to the case when the image reading unit 2 is mounted on the imaging device 1. This makes it easy for anyone to operate the image reading unit 2, thus improving convenience.
Japanese Patent Application Laid Open No. 2002-101242 and Japanese Patent Application Laid Open No. 2000-131909 disclose examples of the conventional technology.
However, in the conventional electronic apparatus, the optimal lengths of each electric cable 6d, 6e, and 6f differ, depending on how the imaging device 1 and the image reading unit 2 placed on the table 8 are located. In the example shown in FIG. 18, the electric cable 6f is not long enough that it is stretched along the imaging device 1. On the other hand, the electric cables 6d, 6e are too long that they hang down. Accordingly, the electric cables can impair safety or spoil the appearance of the electronic apparatus.

External device and electronic apparatus


A lock including an illuminating device which is actuated by the rotation of a lock dial produces an illumination event. The illumination event provides sufficient light on the lock such as to allow easier operation of the lock in areas of inadequate light. The lock may include a piezo device which creates electrical current to light one or more light emitting diodes for a predetermined duration of time.

Security devices, such as locks, are used in a variety of applications to secure a variety of objects. In some instances the security device may be used in areas of low light, which may impede or complicate operation of the security device. For example, operation of a combination dial to locate the correct number of the unlocking combination or locating the keyhole for insertion of the appropriate key may be difficult in areas of low light. As such, it is desirable to provide a security device that produces sufficient light to allow easy operation of the security device.


The present invention is an apparatus for restricting the flow of fluid. The apparatus defines a tubular member having a channel. The tubular member has a first portion in which the channel has a first cross sectional area. There is also a second portion for restricting the flow of fluid defined by a reproducible deformity in the channel such that the channel has a second cross sectional area which is smaller than the first cross sectional area of the first portion. The tubular member further defines a third portion having a third cross sectional area which is greater than the second cross sectional area of the second portion. All of the cross sectional dimensions of the second and third portions are disposed within a cylindrical envelope having a diameter equal to the diameter of the first portion and extending therefrom. The tubular member is comprised of a material having sufficient rigidity to maintain a preferred reproducible permanent deformity in the channel. Portion has an essentially constant outside diameter and wherein all cross sectional dimensions of the tubular member are less than or equal to the diameter of the first portion and all of the cross sectional dimensions of the second and third portions are disposed within a cylindrical envelope having a diameter equal to the diameter of the first portion and extending therefrom. Preferably, the deformity is defined by a spherical indentation and the tubular member is comprised of stainless steel. The present invention is also a method of forming a fluid restrictor comprising the steps of first placing a tubular member having a channel and a predetermined outside diameter into a fixed relationship with a deforming apparatus. Then, there is the step of deforming the tubular member in a reproducible manner such that a cross sectional area of the channel is decreased so flow of fluid through the channel is restricted a desired amount. The deforming step does not cause the tubular member to flare and all of the cross sectional dimensions of the second and third portions disposed within a cylindrical envelope having a diameter equal to the diameter of the first portion and extending therefrom. Preferably, the deforming step includes the step of forcing a shaping element of the deforming apparatus against the tubular member. Alternatively, the deforming apparatus can be used to adjust the magnitude of fluid restriction during operation of the fluid restrictor.

It is known in the art of high pressure fluid or supercritical fluid restrictors to restrict the flow of fluid with fluid restrictors instead of valves because the fluid flow rates, which can be in the range of 10 microliters/min. to 10 ml/min., are too low for accurate and reproducible flow control by conventional valves.
In one type of fluid restrictor, holes are formed in a circular disc that are supported in the path of the flowing fluid by the necessary hardware, seals and fittings.
A problem exists with such fluid restrictors in that the small size of the hole and its abrupt change in cross sectional area allow it to become clogged easily. This is an undesirable event in that it typically entails dismounting the fluid restrictor so that it can be cleaned or replacing it altogether.
It is also known to use linear fused silica tubing having a small internal channel as a fluid restrictor. Tapered fused silica restrictors are also formed by heating and drawing out the fused silica tubing until the internal channel is the appropriate dimension. (T. L. Chester, D. P. Innis, G. D. Owens, Analytical Chemistry, 57 (1985) 2243-2247).
"Integral" fused silica restrictors (E. J. Guthrie, H. E. Schwartz, J. Chromatographic Science, 24 (1986) 236-241) are formed by heating the end of the fused silica tubing until it melts shut. Then, sending away the end until a small hole is formed Ceramic frits have also been formed at the ends of the fused silica restrictor (K. E. Morkides, S. M. Fields, M. L. Lee, J. Chromatographic Science, 24 (1986) 254-257). A review of restrictors is given by B. W. Wright, R. D. Smith, "Restrictor Performance Characteristics for SFC", Chapter 10 of Book Modern Supercritical Fluid Chromatography, Ed C. M. White, Dr. Alfred Huthig Verlag, ISBN 3-7785-1569-1, 1988.
A length of fused silica tubing does better as a restrictor than a hole in a disc as it plugs less often, but it is limited by other deficiencies including 1) it is brittle and can break easily, 2) one must use a long length, typically 10 to 100 centimeters which makes its use inconvenient to the user, and 3) since the tube is glass, it is a poor thermal insulator and thus it is difficult to heat. Heat has been shown to reduce clogging in fluid restrictors.
Fluid restrictors have also been constructed by crimping a stainless steel or platinum tube with pliers to deform the wall thereby decreasing the cross sectional area of the channel within. Though such restrictors are less prone to clogging, the pliers cause the outer diameter of the wall to become greater than its original value in places. This flaring of the tube prevents a snug fit in the appropriate fittings. Thus, efficient heat transfer is limited. A further problem exists in that it is difficult if not impossible to reproduce the shape or profile of the deformity. This limits the accuracy in predicting the magnitude of fluid restriction and the aversion to clogging.
The present invention provides a fluid restrictor wherein the wall is deformed such that the channel within is restricted without flaring of the walls and the deformity is reproducible. The operation of these restrictors occurs at temperatures of 50.degree. C. to 250.degree. C. to further reduce clogging.

Fluid restrictor apparatus and method for making the same


In an intake air flow control valve device a flange formed in a housing of the intake air flow control valve device is bolted to a cylinder head via a first gasket and a second gasket along opening outer peripheries of a first intake air passage and a second intake air passage, which are opened to a mount surface of the flange between the flange and a mount surface of the cylinder head.

1. Technical Field
The present invention relates to a mount structure of an intake air flow control valve device. In particular, the present invention relates to a mount structure for mounting, on a cylinder head, an intake air flow control valve device that is disposed in an intake manifold of an engine and controls an intake air flow formed in a combustion chamber.
2. Related Art
An intake air flow control valve device that is disposed in a resin intake manifold and controls an intake air flow formed in a combustion chamber is proposed, as disclosed in Japanese Unexamined Patent Application Publication (JP-A) No. 2007-303327, for example.
The intake air flow control valve device is applied to a four-cylinder engine, and includes a resin intake manifold 101 and valve units 104, as illustrated in an exploded perspective view of FIG. 7. In the intake manifold 101, four intake air passages 102 are formed by separation walls 101a, and each of the valve units 104 is disposed in each of the intake air passages 102.
The valve unit 104 includes a frame shaped housing 105, an intake air flow control valve 106, and a valve shaft 109. The plate shaped intake air flow control valve 106 has bosses protruding to bath sides, and each of the bosses is rotatably supported by a supporting hole of the housing 105 via a bearing. The valve shaft 109 penetrates a separation wall through-hole 101b of the intake manifold 101 and holes formed at the bosses of the intake air flow control valves 106. Thereby, the intake air passages 102 are opened and closed by synchronous rotation of the intake air flow control valves 106 in association with rotation of the valve shaft 109.
Further, in an intake air flow control valve device disposed in another intake manifold, a flange 114 is provided at an end of a housing 112 including intake air passages 113A and 113B, as illustrated in FIG. 8, which is a cross-sectional view of principal parts. The intake air passages 113A and 113B are adjacent to each other and communicated by a shaft penetrating unit 116 that has a shaft hole 116a.
A mount surface of the flange 114 formed at the end of the housing 112 is provided with annular gaskets 115a and 115b along respective opening outer peripheries of the intake air passages 113A and 113B.
A valve shaft 118 penetrates through the intake air passages 113A and 113B, and the shaft hole 116a. The distal end of the valve shaft 118 is rotatably supported, via a bush 119, by a supporting hole 112a formed at the outer end of the intake air passage 113B of the housing 112. The base end of the valve shaft 118 is coupled with an actuator 120, such as an electric motor, provided outside the intake air passage 113A of the housing 112. Plate shaped intake air flow control valves 117A and 117B, which are disposed in the intake air passages 113A and 113B, respectively, are provided on the valve shaft 118. Thereby, the intake air passages 113A and 113B are opened and closed by synchronous rotation of the intake air flow control valves 117A and 117B in association with rotation of the valve shaft 118 by the actuator 120.
In an intake air flow control valve device 111 thus configured, the flange 114 is bolted to a mount surface 151 of a cylinder block 150, where intake air ports 152a and 152b are opened via gaskets 115a and 115b.
According to JPA No. 2007-303327, the bosses, which is provided at the both sides of the respective intake air flow control valves 106, are rotatably supported by the housings 105 via bearings. However, the resin intake manifold and the housing 105 are not uniform in manufacturing shape and dimensional accuracy, and have low rigidity, compared with the conventional intake manifolds and housings made of metal, such as aluminum. Thus, deformation may be caused by environmental changes, such as increases and decreases in temperature by use. The deformation of the intake manifold and the housing 105 may hinder smooth operation due to deterioration in concentricity between the bosses of the intake air flow control valves 106 and the bearings.
In the intake air flow control valve device 111 illustrated in FIG. 8, deformation of the housing 112 caused by environmental changes, such as increases and decreases in temperature may also occur, since the resin intake manifold and the housing 112 are not uniform in manufacturing shape and dimensional accuracy, the resin housing 112 and the metal valve shaft 118 have different coefficients of thermal expansion respectively, the actuator 120 is disposed at the outer end at one intake air passage 113A side of the housing 112, and the bush 119 to pivotally support the distal end of the valve shaft 118 is disposed at the outer end at the other intake air passage 113B side of the housing 112. For example, as indicated by a virtual line 112b, the housing 112 may be deformed into a curved shape in a direction in which the end at the intake air passage 113B side, where the bush 119 is disposed, move away from the mount surface 151 of the cylinder head 150, with respect to the end at the intake air passage 113A side, where the actuator 120 is provided.
In this deformation, the displacement amount by which the bush 119 pivotally supporting the distal end of the valve shaft 118 moves away from the cylinder head 150 becomes large, and thus, the tilt of the shaft hole 116a of the shaft penetrating unit 116 may become larger than the tilt of the valve shaft 118. Accordingly, the concentricity between the valve shaft 118 and the shaft hole 116a is deteriorated, and thus, the valve shaft 118 and an inner peripheral surface of the shaft hole 116a come into contact with each other. As a result, operating performance may be possibly deteriorated.
If the shaft hole 116a having a large diameter is formed so as to avoid the contact between the valve shaft 118 and the shaft hole 116a of the shaft penetrating unit 116, a large gap is formed between the inner peripheral surface of the shaft hole 116a and the valve shaft 118. The intake air flowing through the intake air passage 113A and the intake air flowing through the intake air passage 113B are communicated and interfered with each other through the gap, thereby generating turbulence in the intake air passages 113A and 113B. As a result, deterioration in intake characteristic occurs since an intake air flow in a combustion chamber is not smoothly generated, and thus, combustion efficiency of the engine lowers, resulting in lowering output.

Mount structure of intake air flow control valve device


Disclosed are a wet spinning apparatus and a wet spinning method, which enable to manufacture fibers with excellent quality by controlling the flow of a coagulation liquid in a spinning bath and which enable to cope with high speed spinning (or high speed drawing). A wet spinning apparatus comprises a spinning bath at one end in which there are provided a nozzle for discharging a spinning raw liquid and coagulation liquid discharge ports and for discharging a coagulation liquid, at the other end in which there are provided a drawing roll for drawing coagulated filaments and a coagulation liquid recovery portion into which the coagulation liquid flows out. The spinning bath has a coagulation bath portion having a cross sectional area gradually reduced from one end to the other end, for coagulating the spinning raw liquid, and a filament running portion having a cross sectional area gradually enlarged from one end to the other end, for allowing the coagulated filaments to run therein.

A wet spinning apparatus is an apparatus for solidifying a spinning raw liquid prepared by dissolution of an organic polymer in a solvent into a fiber form by discharging the spinning raw liquid from a nozzle into a coagulation liquid. Acrylic fibers, polyvinyl fibers, and other acrylic based fibers can be produced by the wet spinning apparatus.
The wet spinning apparatus is generally equipped with a spinning bath in which a coagulation liquid is contained, a nozzle immersed at one end in the spinning bath, and a drawing roll immersed at the other end in the spinning bath, wherein a spinning raw liquid discharged from the nozzle is coagulated by the coagulation liquid and thus formed into coagulated filaments which are then drawn out of the spinning bath through the drawing roll. The coagulation liquid is discharged into the spinning bath from a coagulation liquid discharge port disposed on the rear surface side of the nozzle, and is caused to flow to a running direction of the coagulated filaments while coagulating the coagulated filaments, and is caused to flow out into a coagulation liquid recovery portion from a spinning bath outlet port disposed at the other end in the spinning bath. Fibers (coagulated filaments) solidified in the spinning bath are separated from the coagulation liquid, washed, and transferred to the subsequent steps such as chemical liquid treatment, drying, and thermal treatment.
The speed of spinning and drawing of the coagulated filaments is generally set faster than the average flow rate of the coagulation liquid to be supplied into the spinning bath. As a result, the coagulation liquid flowing in the vicinity of the coagulated filaments is attracted by and accompanies the coagulated filaments, and is caused to flow to the direction of drawing with a velocity near a spinning speed (hereinafter, this is referred to as "accompanying flow"). At the same time, there occurs a phenomenon such that the coagulation liquid flows backward from the downstream side to the upstream side to compensate the accompanying flow at a place near the bottom wall or the sidewall which is distant from the coagulated filaments in the spinning bath. In this way, there have been simultaneously and adjacently generated two flows contrary to each other, namely the accompanying flow and the counter flow, in the spinning bath, so that the flows have interfered each other to cause irregular flow of the coagulation liquid and thus there have been partially generated whirlpools and stagnation.
When such whirlpools and stagnation were generated in the spinning bath, there was a case where filament waste (nest) derived from break of a single fiber caused by poor coagulation of the spinning raw liquid floated in the spinning bath and lumps of the filament waste came into contact with the coagulated filaments and thereby deterioration of quality and performance of the product was caused. In addition, when the spinning speed was raised to improve productivity, stable production was disturbed because turbulent flow of the coagulation liquid became more remarkable and the coagulated filaments were shaken and thus diameter-unevenness or break of a single fiber was generated.
Therefore, the following wet spinning apparatus has been proposed to solve the above-mentioned problem.
A wet spinning apparatus equipped with rectifying plates provided on both sides of the coagulated filaments along with the running direction of the coagulated filaments (for example, Patent Document 1). As for this wet spinning apparatus, turbulence of the flow of the coagulation liquid can be suppressed by the rectifying plates.
However, as for such a wet spinning apparatus, there was a case where the flow rate of the coagulation liquid at a part where the coagulation liquid flowed out from the spinning bath became too fast and thus turbulence of the coagulated filaments (tow) was caused.
Accordingly, there has been proposed a wet spinning apparatus in which a coagulation liquid-partitioning plates (rectifying plates) for partitioning the coagulation liquid are provided between the coagulated filaments and walls of the spinning bath standing in parallel with the running direction of the coagulated filaments, and holes (openings) for drawing out coagulation liquid are formed on the coagulation liquid-partitioning plates (for example, Patent Documents 2 to 4). As for this wet spinning apparatus, the inside of the spinning bath is separated into an inner bath which is located inside the coagulation liquid-partitioning plates and in which the coagulated filaments are running, and outer baths located on both sides of the inner bath; the accompanying flow generated in the spinning bath is allowed to flow inside the inner bath toward downstream side, and the counter flow is allowed to flow inside the outer baths toward upstream side. In addition, it is possible to restrain the flow rate of the coagulation liquid from being too fast by causing the coagulation liquid to flow out from the inner bath to the outer baths through the openings.    Patent Document 1: Japanese Patent Application Laid-Open No. Sho 62-33,814    Patent Document 2: Japanese Patent Application Laid-Open No. Hei 9-67,714    Patent Document 3: Japanese Examined Utility Model Publication No. Sho 41-18,091    Patent Document 4: Japanese Patent Application Laid-Open No. Hei 11-229,227


The disclosed semiconductor memory device exhibits improved error correction capability shorter read/write times, and removes or reduces the need for redundant memory The semiconductor device has a data input portion for receiving one page of data, dividing it to a plurality of code words, generating and adding check code (parity data) for each code word, successively forming main code words, and transferring the main code words to one of a plurality of memory banks. The semiconductor device also includes a data output portion for receiving one page worth of data, including main code words transferred from the data latch circuit, correcting errors in the data when the data includes fewer than a predetermined number of errors for each main code word, adding the error information to each read code word, and outputting the result.

1. Field of the Invention
The present invention relates to a NAND type flash memory or other semiconductor memory device having memory strings connected to bit lines and source lines via selection switches and to a signal processing system provided with such a semiconductor memory device, more particularly relates to an error correction processing technology of a semiconductor memory device.
2. Description of the Related Art
In a NAND type flash memory, a plurality of memory transistors are connected in series to form memory strings. Two memory strings share one bit contact and source line, whereby a higher integration is achieved.
In a general NAND type flash memory, an erase operation is performed by, for example, applying 0V to all word lines to which a selected memory string is connected, making all word lines to which unselected memory strings are connected floating states, and applying a high voltage (20V) to the substrate of the memory array. As a result, electrons are drained from the floating gates to the substrate for only the memory transistors of the selected memory string. As a result, the threshold voltages of the memory transistors shift to the negative direction and become, for example, −3V.
Further, data is written in units of so-called "pages" of several hundreds to several thousands bytes for memory transistors connected to the selected word line all together. Specifically, for example, a high voltage (for example, 18V) is applied to the selected word lines, 0V is applied to bit lines to which memory transistors into which data is to be written (0 data) are connected, and a high level voltage (for example 3.3V) is applied to bit lines to which memory transistors for which the writing is to be prohibited (1 data) are connected. As a result, electrons are injected into the floating gates for only the selected memory transistors into which the data is to be written. The threshold voltages of the selected memory transistors shift to the positive direction and become, for example, about 2V.
In such a NAND type flash memory, data is both written and erased by an FN (Fowler Nordheim) tunnel current, so there is the advantage that supply of an operation current from a booster circuit in a chip is relatively easy and operation with a single power supply is easy. Further, since the data is written into the memory transistors connected to the selected word lines all together in units of pages, this is superior to a NOR type flash memory in the point of the write speed.
In a nonvolatile semiconductor memory device for performing page write operations in units of word line sectors like the above mentioned NAND type flash memory, the data is written into all memory cells connected to the selected word line all together. However, the memory cells connected to the selected word line vary in size due to the production process, so differences occur in the write speed. Specifically, in a nonvolatile semiconductor memory device performing page write operations in units of word line sectors like a NAND type flash memory, a distribution arises in the time required for writing among memory cells.
Taking such variation as the write speed in account, from the viewpoint of keeping the distribution of the threshold voltage Vth at the time of the write operation narrow in a general NAND type flash memory, etc., the write operation is carried out through a verify operation. This write/verify operation is repeated until all memory cells finish being written by successively prohibiting the write operations from the memory cell finished being written for a so-called bit verify operation. In the case of a general memory cell, however, the time taken for programming is t0, but there will sometimes very rarely be memory cells which take an extremely long programming time of, for example, t1 (>t0) or more due to variation in the process. In such a case, the number of times of the above write/verify operation is set to a large number of, for example, 100 times or more for such a rare memory cell with such a slow write speed.
Further, the data is read into the NAND type flash memory by establishing the data stored in the memory cells through a sense amplifier and storing the data in a data register in units of random accessed pages, then serially transferring the page data to the outside in units of one or two bytes. Specifically, for example, a voltage of 0V is supplied to the selected word line and a voltage of about 4V is supplied to the unselected word lines. In the case of a NAND type flash memory, a plurality of memory cells is connected in series, therefore the read current of the memory cells is small in comparison with the NOR type flash memory, and thus the so-called "random access time" for establishing the data stored in the memory cells through the sense amplifier is long.
Further, in error correction of a nonvolatile semiconductor memory device, such as a NAND type flash memory, a redundant memory area is provided. A defective portion is found before shipment of the product and physically replaced by this redundant memory. The main type of error correction code (ECC) used is a hamming code, BCH code, or other code for error correction in units of bits.

Semiconductor memory device and signal processing system


A pin support assembly includes a pin support frame having a plurality of apertures for supporting an array of pins for dispensing fluids. The pins are supported for longitudinal or “floating” movement to prevent damage to the pins. An actuation assembly engages an end of each of the pins to ensure that the pins are properly seated in the support frame in a planar fashion. The actuation assembly engages the pins as the pins move relatively toward a head block and disengages the pins as the pins move relatively away from the head block.

1. Field of the Invention
The present invention is generally related to apparatus for dispensing controlled amounts of fluid.
2. Description of the Related Art
Many research and/or manufacturing settings require the delivery of a precise amount of fluid. Precisely controlling the delivery of fluid can be important to producing accurate test results or to producing high quality products, as well as being important in lowering costs associated with such operations. Often, these applications require a large number of repetitive operations. For example, biological or chemical assays may employ hundreds, thousands, or more of individual testing steps. Efficiency, accuracy and repeatability require that these operations be automated. One method of automating is to perform multiple tests at discrete locations on a single plate (i.e., plate, slide, or array). This requires the delivery of very precise amounts of fluids, for example agents or reagents, to hundreds or even thousands of locations on the plate. Other automated methods are of course possible. The cost of high precision automated equipment is typically substantial.
One approach to delivery of a controlled amount of fluid employs pipette tips. The pipette tip relies on capillary action to draw a precise amount of fluid from a reservoir into an internal passage of the pipette tip, for delivery to the desired location. Pipette tips may be particularly suitable for dispensing fluids in the micro-liter range.
U.S. Pat. No. 5,497,670 issued Mar. 12, 1996 discloses a dispensing apparatus including means for loading pipette tips carried by a pipette plate onto dispensing cylinders such that a loading force is maintained during the operation to ensure a hermetic seal. The pipette tips are manually placed on the pipette tip plate, the pipette tip plate being slidingly received within the dispensing apparatus.
U.S. patent application Ser. No. 08/751,859 filed Nov. 18, 1996 discloses a dispensing apparatus. The dispensing apparatus is similar to that disclosed in the aforementioned patent, but substitutes a more conventional pipette tip carrier for the pipette tip plate, which is less expensive, less likely to be contaminated, and easily adapted for robotic operation or automation.
U.S. application Ser. No. 10/027,448 filed Dec. 20, 2001 discloses a dispensing apparatus that employs a modified pipette tip box tray carrier to furnish pipette tips carried in a standard pipette tip box to the apparatus, and includes engagement means to engage pipette tip box tray carrier such that the pipette tips are loaded into corresponding internal cylinders formed in a dispense block head of the dispensing apparatus. The dispense block head comprises a solid block of material having a plurality of internal cylinders to engage the pipette tips in a sealing engagement.
A distinctly different approach to precisely dispensing fluids employs one or more pins to retrieve a desired amount of fluid from a reservoir, and to dispense the retrieved fluid to a desired location. In contrast to pipette tips, these pins do not include an internal passage, but rather retrieve a small sample of the fluid as the pin is removed from a reservoir, the fluid forming a droplet on the outer surface at the end of the pin. The amount of fluid retrieved by the pin is a function of a number of parameters including the size, shape and material of the pin and the viscosity of the fluid, all of which affect surface tension. The pin based approach may be particularly suitable for dispensing fluids in the nano-liter range.
Automating the pin based approach would be highly desirable, as would be the taking advantage of the substantial investment made in existing automated equipment such as pipette based dispensing apparatus.


A boat is formed with a plurality of through-holes sized to securely maintain ceramic or organic flip chip semiconductor packages in place during assembly. Embodiments comprises a boat having a bottom layer with an array of four-sided through-holes and a top layer with an array of through-holes and tabs extending from the sides of the through-hole. Embodiments further include a boat having a bottom layer with through-holes smaller than substantially aligned overlying through-holes in the top layer, the substantially aligned through-holes forming flip chip package holding pockets. An alignment mechanism ensures that components are accurately positioned on flip chip packages held in the boat during assembly.

The present invention relates to the field of semiconductor packaging, and more specifically to a boat for holding and aligning semiconductor flip chip packages during assembly.
Conventional flip chip package assemblies derive their name from the fact that an interconnect die, having all terminations (e.g., solder pads or bump contacts) on one surface, is flipped over for attachment to a substrate in a manner that allows the interconnect die terminations to couple with the substrate to form an electrical and mechanical connection. Flip chip assemblies and flip chip packages are supported because the interconnect die and other components consume limited substrate space, thereby enabling the formation of flip chip packages having high density and low inductance.
In a conventional flip chip assembly process, the die and substrate pass through flux dipping and chip mounter machines, wherein a bonding material, such as solder, is applied to the die and substrate and then the parts are mounted together. The die/substrate combination is then passed through a reflow oven that heats the bonding material to a temperature adequate to melt the material and attach the die to the substrate. The semi-assembled flip chip package can then be transported to a flux cleaning machine, an underfill dispenser and a vertical cure oven. Manufacturers can alter this process by adding or removing steps. The elements of each step may also vary depending on the particular semiconductor package being assembled and a manufacturer""s specific requirements.
In an effort to improve yield percentages and increase production speeds, many of the machines involved in flip chip assembly are typically programmed to perform the same function repeatedly and according to standardized parameters. Standardized package location is one such parameter. Flip chip assembly machines are programmed to assume that a package is in a precise location when the package enters a particular assembly step, such as die mounting, fluxing or seal placement. This allows the machine to go to the same location every time in order to complete its assigned task in the assembly process. In order for this kind of standardized repetition to yield positive production benefits, the package must be precisely positioned at an expected location, otherwise inefficiency results. For example, the machine will still complete its task without regard to package location resulting in an improperly assembled package that must either be reworked or discarded. In other instances, the machine may be programmed to look for the package before performing its assigned task, thereby reducing the need for rework, but also disadvantageously slowing production. Consequently, semiconductor device production is improved when the components are held in a precise location throughout the assembly process in way that allows each machine to perform its task as programmed.
Unassembled and semi-assembled flip chip packages are usually held in a carrying device during flip chip assembly. Carrying devices are useful because they make it easier for manufacturers to transport packages without direct physical contact, thereby reducing the likelihood of contamination and other damage attendant upon excessive handling. Carrying devices also make it easier to increase production speeds, because their ability to hold multiple flip chip packages allows manufacturers to move several packages at once and allows machines to work on more than one semiconductor package at a time or to move quickly from one package to another. However, a manufacturer""s ability to enjoy these benefits depends on whether package placement can be maintained in a standardized location during flip chip assembly. However, such package retention is difficult for at least two reasons.
First, semiconductor packages come in varying dimensions, thereby imposing a limitation on the extent to which manufacturers can rely on a carrying device maintaining a package in a precise location. For example, some packages are too large to fit into a standardized carrying device holding pocket, while others are so small that they fall through the hole in the bottom of the pocket. Package weight also affects package retention in a carrying device holding pocket. For example, lighter packages are easily jostled out of the pocket during transport or assembly. If a flip chip package does not fit or remain in the carrying device holding pocket, a machine will not operate properly according to package location-dependent instructions.
Existing carrying device designs exacerbate this problem. Currently, the same carrying device holds flip chip packages of all sizes, supported on a single shelf. The pocket opening, shelf size and hole though the pocket bottom are not designed to accommodate specific package sizes. Thus, if the package is smaller in length or width than the pocket opening, the package can slide around on the shelf in varying directions (e.g., side to side, up and down, or pivoting from a package corner). The resulting friction or collision between the carrying device and the flip chip package can damage the substrate, die or any other attached flip chip package elements (e.g., pins or balls). Furthermore, this movement moves the flip chip package from its precise location within the carrying device holding pocket, therefore increasing the likelihood that a flip chip assembly machine will be unable to properly perform its assigned task.
There is a need for a carrying device that can retain flip chip packages (e.g., ceramic or organic flip chip packages) in place during flip chip assembly.
The present invention comprises a boat for maintaining flip chip packages in place during assembly. Embodiments of the present invention include a boat for holding flip chip packages (e.g., ceramic or organic flip chip packages) having a bottom layer with an array of four-sided through-holes and a top layer having an array of through-holes with tabs extending from the sides of the through-hole. Each through-hole in the bottom layer is smaller than the overlying top layer through-hole. The top layer is attached to the bottom layer so that the central axis of each bottom layer through-hole is substantially aligned with the central axis of an overlying top layer through-hole. An alignment mechanism ensures that lids are accurately placed on flip chip packages held in the boat during assembly.
Boats in accordance with embodiments of the present invention advantageously maintain organic and ceramic flip chip packages in place in a standardized location in the boat during assembly, thereby improving production standardization and enabling assembly steps to be completed rapidly and repeatedly with little or no human intervention. In addition, damage that can occur when an assembly step is attempted or completed on a ceramic or organic flip chip package improperly seated in the boat is avoided or significantly limited.
In accordance with embodiments of the present invention, packages are prevented from extending through or falling out of the boat, thereby increasing manufacturing through put and reducing costs vis-xc3xa1-vis conventional carrying devices. In addition, boats can be designed to accommodate flip chip packages of varying sizes, thereby enabling manufacturers to use the same boat for many different flip chip packages, eliminating the need for multiple boats and for retrofitting assembly equipment to accommodate different flip chip boat designs.
Other advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description. The embodiments shown and described provide illustration of the best mode contemplated for carrying out the invention. The invention is capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawings are to be regarded as illustrative in nature, and not as restrictive.

Boat for organic and ceramic flip chip package assembly


Embodiments of a network architecture include a backbone node having a plurality of independent routers or switches connected in a matrix, wherein the matrix includes a plurality of stages of routers or switches, to form a node having a node switching capacity that is greater than the node switching capacity of the individual routers or switches. A method includes assigning one of a plurality of backbone networks to a destination network address, associating a next hop loopback address with the destination network address, and advertising the destination network address in combination with the next hop loopback address through the selected backbone network address.

High speed internet prices continue to drop, but the underlying costs of maintaining and operating the networks remain relatively high. One of the main factors in keeping the unit costs high is the high cost for the terabit Multiple protocol Label Switching (MPLS) backbone routers. Accordingly, as bandwidth requirements grow, the costs will likely grow as well.

Systems and methods for network routing in a multiple backbone network architecture


A CPU heat sink fastener includes a retainer member having two V-shaped arms extended from a flat base thereof and respectively hooked in respective locating holes on a CPU module to hold down a heat sink on the CPU module, and a holding down member having a longitudinal slot forced into engagement with the V-shaped arms. The holding down member is pushed to a position below reinforcing ribs at the V-shaped arms to force the V-shaped arms inwards and to secure the retainer member in place.

The present invention relates to a CPU heat sink fastener for fastening to a CPU module to secure a heat sink to the CPU module, and more particularly to such a CPU heat sink fastener which has a simple structure, and can easily be positively installed.
Various CPU heat sink fasteners have been developed for use in securing a heat sink to a CPU module. These heat sink fasteners commonly use the curved spring plate to secure a heat sink to the CPU module, and lock levers to lock the curved spring plate in position. However, the lock levers tend to be forced out of locking position during delivery.


A compact MOS array including word lines perpendicular to and overlapping bit lines, is fabricated by etching trenches in the underlying silicon and then forming successive bit lines within the trenches and upon the intervening mesas. Subsequent implantation of dopant into trench sidewalls creates channel regions oriented at an angle relative to the horizontal bit lines. Disposing successive diffused bit lines in vertically separated planes enables fabrication of ROM cells having full channel lengths which occupy a smaller surface area. Tilted ion implantation may be utilized to introduce dopant into channel regions.

1. Field of the Invention
The present invention relates to an array of MOS semiconductor devices and a process for forming the array, and in particular, to a ROM array having successive bit lines disposed in vertically separated planes, thereby minimizing the horizontal surface area occupied by the array.
2. Description of the Related Art
FIG. 1 shows a plan view of an NMOS ROM array formed in a single horizontal plane, as disclosed in U.S. Pat. No. 5,590,068 ("the '068 Patent"). FIG. 1A shows a cross-sectional view along line 1A-1A'. FIG. 1B shows a cross-sectional view along line 1B-1B'.
The '068 patent teaches creation of an alternate virtual ground ROM array 100 of data storage cells 102. In FIG. 1, the array is shown as a plurality of NMOS ROM devices formed within lightly doped P-type silicon 114. ROM data storage cells 102 are defined by overlapping of a word line 104 over a pair of diffused bit lines 106. Diffused bit lines 106 actually consist of global diffused bit lines 106a alternating with local diffused bit lines 106b. Local diffused bit lines 106b are grounded and serve as the sources of cells 102 of array 100.
Polysilicon word lines 104 are oriented perpendicular to diffused bit lines 106 and are separated from bit lines 106 by a gate oxide layer 108. Where a polysilicon word line 104 crosses over channel region 110 between successive diffused bit lines 106a and 106b, MOS semiconductor device 102 is formed having local diffused bit lines 106b as the source, global diffused bit line 106a as the drain, word line 104 as the gate, and gate oxide layer 108 as the gate.
Array 100 is divided into segments. Within each segment, the size of each cell 100 can be estimated by the pitches of word lines 104 and diffused bit lines 106. For design rules based upon a pitch of .lambda., the cell size is 4.lambda..sup.2. This calculation is based on an array structure in which all diffused bit lines and cell transistors are disposed in the same horizontal plane.
The ROM array structure disclosed by the '068 Patent is adequate to perform its intended function. However, this ROM structure consumes substantial amounts of surface area of the underlying silicon.
Therefore, there is a need in the art for a ROM array structure and a process for forming such an array structure that is more compact and occupies less silicon surface area.

Process to manufacture high density ULSI ROM array


An articulated two-section snowboard has a first and second section joined together for twisting and oscillation. Each section has an upper surface, a lower surface and an outer portion and an inner portion. A flexible connector joins the inner portions of the first and second sections and a pair of bindings for securing the feet of a user to the upper surface of the first and second sections.

In the past, snowboards have comprised a single surface, with upwardly curved tips on each end having various degrees of width and rigidity. Such a snowboard has been equipped with forward and rear bindings for attaching the user's boots to the snowboard.
Prior snowboards have been limited in their ability to make sharp turns and to smoothly proceed over uneven surface. The rigid elongated nature of prior snowboards has made it awkward to store and transport them and also limits the user in tricks or aerial acrobatics.
When utilizing a chair lift, prior rigid snowboards tend to angle off to one side, intruding into the space and skis of co-passengers.
The rigidity of prior snowboards also presents a challenge to the user in returning to an upright position in the event the user should fall.


A device and method for dynamically tuning a long-period grating of an optical fiber is disclosed. The grating is made tunable by using a controlled strain imposed on the fiber adjacent the grating, wherein the strain comprises an electromechanical force, magnetostrictive force, magnetic force, or a thermally-induced force. An improved optical communication system comprising a dynamically gain-equalized amplifier device, a wavelength feedback device, and the tunable long-period grating device is also disclosed. In the communications system, the grating device is reconfigured to have a desired broadband filtering frequency, thus equalizing the amplifier gain, in response to feedback from the wavelength detector.

Of the technology available for achieving high data rate transmission over optical fibers, densely- spaced wavelength-division multiplexing (WDM) is a promising candidate. Optical fibers are key components in modem telecommunication systems. Basically, optical fibers are thin strands of glass capable of transmitting an optical signal containing a large amount of information over long distances with very low loss. In essence, an optical fiber is a small diameter waveguide comprising a core having a first index of refraction surrounded by a cladding having a second (lower) index of refraction. Typical optical fibers are made of high purity silica with minor concentrations of dopants to control the index of refraction.
A typical optical fiber communications system comprises a source of optical input signals, a length of optical fiber coupled to the source, and a receiver coupled to the fiber for receiving the signals. One or more amplifying devices are disposed along the fiber for amplifying the transmitted signal. Pump energy must be supplied to operate the amplifier. Contemplated optical fiber systems use digitally modulated optical signals at a wavelength of 1.55 micrometers and erbium-doped fiber amplifiers.
One problem limiting the capacity of such systems is that the erbium-doped fiber amplifier has a characteristic spectral dependence providing different gain for different wavelength channels. This spectral dependence poses a problem for multichannel WDM systems, because different gains for different channels leads to high bit error rates in some of the channels. In this case, a spectral shaping device helps flatten the gain spectrum of the amplifier.
Long-period fiber grating devices provide wavelength dependent loss and may be used for spectral shaping. A long-period grating couples optical power between two copropagating modes with very low back reflections. A long-period grating typically comprises a length of optical fiber wherein a plurality of refractive index perturbations are spaced along the fiber by a periodic distance .LAMBDA. which is large compared to the wavelength .lambda. of the transmitted light. In contrast with conventional Bragg gratings, long-period gratings use a periodic spacing .LAMBDA. which is typically at least 10 times larger than the transmitted wavelength, i.e. .LAMBDA.>10.lambda.. Typically .LAMBDA. is in the range 15-1500 micrometers, and the width of a perturbation is in the range 1/5.LAMBDA. to 4/5.LAMBDA.. In some applications, such as chirped gratings, the spacing .LAMBDA. can vary along the length of the grating.
Long-period fiber grating devices selectively remove light at specific wavelengths by mode conversion. In contrast with conventional Bragg gratings in which light is reflected and stays in the fiber core, long-period gratings remove light without reflection by converting it from a guided mode to a non-guided mode. A non-guided mode is a mode which is not confined to the core, but rather, is defined by the entire waveguide structure. Often, it is a cladding mode. The spacing .LAMBDA. of the perturbations is chosen to shift transmitted light in the region of a selected peak wavelength .lambda..sub.p from a guided mode into a nonguided mode, thereby reducing in intensity a band of light centered about the peak wavelength .lambda..sub.p. Alternatively, the spacing .LAMBDA. can be chosen to shift light from one guided mode to a second guided mode (typically a higher order mode), which is substantially stripped to provide a wavelength dependent loss.
Long-period grating devices are thus useful as filtering and spectral shaping devices in a variety of optical communications applications. Key applications include spectral shaping for high-power broadband light sources (C. W. Hodgson, et al., 9 Optical Society of America Technical Digest Series, Paper TuG3 (1996)), gain equalization for optical amplifiers (A. M. Vengsarkar et al. 21 Optical Letters 336, (1996)), band rejection in cascaded high-power Raman lasers (S. G. Grubb et al., Laser Focus World, p. 127 (February 1996)), and filtering amplitude spontaneous emission in erbium doped amplifiers (A. M. Vengsarkar et al., 14 J. Lightwave Technol. 58 (1996)). See also U.S. Pat. No. 5,430,817 on "Optical Systems and Devices Using Long Period Spectral Shaping Devices" by A. M. Vengsarkar, issued on Jul. 4, 1995.
One use of the long-period gratings is flattening the gain of broadband amplifiers for WDM systems. For WDM applications, multiple channels, each operating at several gigabits per second, must be accommodated within the 1530- to 1560-nm band of an erbium-doped fiber amplifier (EDFA). A nonuniform amplifier gain profile, however, leads to uneven signal amplitudes in the different channels, an effect exacerbated by the gain-peaking tendency of an amplifier chain. This amplitude variation between channels can be canceled out by a device with a transmission spectrum matched to the inverted erbium gain spectrum.
A difficulty with conventional long-period gratings, however, is that their capability to equalize amplifier gain is limited, because they filter only a fixed wavelength acting as wavelength-dependent loss elements. Each long-period grating with a given periodicity (.LAMBDA.) selectively filters light in a narrow bandwidth centered around the peak wavelength of coupling, .lambda..sub.p. This wavelength is determined by .lambda..sub.p =(n.sub.g -n.sub.ng).multidot..LAMBDA., where n.sub.g and n.sub.ng denote the effective index of the core mode and the cladding mode, respectively. The values of n.sub.g and n.sub.ng are dependent on the relative values of the refractive indices of the core, cladding, and air.
In a long-period grating, transmission loss can be tailored by inducing different levels of index change in the fiber during fabrication, i.e., by choosing different materials for fabricating the core and cladding of the optical fiber. For example, an erbium gain spectrum is first decomposed into a sum of two Gaussians. Two filters are fabricated, their shapes tailored by varying the exposure times. These gratings are then concatenated to produce a composite transmission spectrum. Used in conjunction with an erbium-doped fiber amplifier, this device can yield a flat gain spectrum with variation less than 0.2 dB over a 25- to 30-nm band.
While long-period gratings may be fabricated to address the transmission loss in WDM systems, the effectiveness of the gratings is yet limited. In the future, multi-wavelength communication systems will require reconfiguration and reallocation of wavelengths among the various nodes of a network depending on user requirements, e.g., with programmable add/drop elements. This reconfiguration will impact upon the gain of the optical amplifier. As the number of channels, passing through the amplifier changes, the inversion level of the erbium ions is altered, leading to non-uniform gain shapes. Thus, the amplifier will start showing deleterious peaks in its gain spectrum, requiring modification of the long-period grating used to flatten the amplifier. Modifying the long-period grating implies altering either the center wavelength of the transmission spectrum or the depth of the coupling.
Accordingly, there is a need for a long-period grating for use as a gain equalizer whose transmission spectrum can be controlled as a function of the number of channels and power levels transmitted through the amplifier. It is desirable to have a tunable (or reconfigurable) long-period grating which, upon activation, can be made to dynamically filter other wavelengths (i.e., besides .lambda..sub.p.) Further, it is desirable to be able to selectively filter a broad range of wavelengths, e.g., for efficient operation of multiple-channel WDM in telecommunication systems. This invention discloses such a tunable long-period grating device.

Tunable long-period optical grating device and optical systems employing same


An EGR device includes an EGR flow path, an EGR valve, a stepping motor, a motor driver, a return spring, a speed detector, and an opening degree estimator. The EGR flow path conveys exhaust gas from an exhaust flow path of an engine to an intake flow path. The EGR valve is disposed on the EGR flow path. The stepping motor drives the EGR valve to open to close. The motor driver supplies driving power to the stepping motor. The return spring urges the EGR valve in a valve closing direction. The speed detector detects an output shaft rotation speed of the engine. The opening degree estimator estimates an opening degree of the EGR valve. The motor driver changes a drive frequency of the stepping motor according to variations of the output shaft rotation speed detected by the speed detector and the opening degree estimated by the opening degree estimator.

The disclosure relates to an EGR device that recirculates exhaust gas of an engine to an intake side.
It is known that in an engine mounted in an automobile and the like, exhaust gas recirculation (EGR) that refluxes exhaust gas to an intake side is performed in order to control a combustion state and suppress pumping loss.
In an EGR device that performs EGR described above, a flow rate of recirculated exhaust gas (EGR amount) is controlled so that an actual EGR rate approaches a target EGR rate by, for example, an EGR valve whose opening degree is controlled by using an actuator such as a stepping motor.
As a conventional technique related to driving control of an EGR valve using a stepping motor, for example, Japanese Unexamined Patent Application Publication No. 2014-20247 describes a technique where a pressure difference between a front side pressure and a rear side pressure of the EGR valve is obtained as a front-rear differential pressure, and when the front-rear differential pressure is greater than a predetermined reference value, the stepping motor is energized and controlled with a drive frequency lower than a normal drive frequency during a period from a valve fully closed state to a valve initial opening state.
Japanese Unexamined Patent Application Publication No. 8-326608 describes that the smaller the differential pressure between an upstream side and a downstream side of the EGR valve is, the higher the drive frequency of the stepping motor is set in order to improve responsiveness of driving control.


The present invention is directed to a device for adjustably providing power to at least one electrical load. The device includes a body member. A plurality of terminals are configured to be coupled to a source of the power. A power control circuit is disposed in the body member and coupled between the plurality of terminals and the at least one electrical load. The power control circuit includes at least one variable control mechanism coupled to at least one series pass element. The at least one series pass element is configured to provide power to the at least one electrical load in accordance with the at least one variable control mechanism setting. A frameless front cover member is connected to the body member and has a raised rectangular form factor substantially corresponding to a standard wall plate opening. The frameless front cover assembly has a plurality of switch mechanisms including at least one first switch mechanism coupled to the at least one variable control mechanism and at least one second switch mechanism actuatable without interference from the standard wall plate. The at least one first switch mechanism and the at least one second switch mechanism are characterized by a transverse dimension substantially equal to the transverse dimension of the standard wall plate opening.

1. Field of the Invention
The present invention relates generally to electrical wiring devices, and particularly to power control wiring devices.
2. Technical Background
Power control devices allow a user to adjust the amount of current delivered to an electrical load, such as a light or a motor. When the electric load is a lighting device, the power control device is commonly referred to as a dimmer. If the power control device is configured to control a motor, such as a fan motor, the power control device is referred to as a motor speed controller. Motor speed controllers are also used to control the speed of machinery such as power tools, electric drills, chair lifts, stationary machinery, and other such variable speed motor driven elements.
The core component of the power control device is commonly referred to as a series pass element. The amount of current provided by the series pass element is varied by a user-actuated switch mechanism. The switch mechanism may be a continuously variable switch or a selector switch mechanism that selects from a predetermined number of discrete switch settings. The series pass element may be implemented using a solid state switch. The active switching element in a solid state switch may be a transistor, a MOSFET device, a gate turn-off device, or a thyristor device, such as silicon controlled rectifier (SCRs) or a triac device. When the series pass element in a fan speed control device is a variable impedance, the power control device is commonly referred to as a "dehummer."
As those of ordinary skill in the art will appreciate, power control devices are typically packaged in a wiring device form factor for installation in an outlet box. Of course, one or more of the power control devices described above may be disposed within the device housing. A unit equipped with both a fan motor and a lighting element, for example, may be controlled by a wiring device that includes both a dimmer and a fan speed control. The exterior of the wiring device includes either screw terminals or wire terminals for subsequent connection between the AC power source and the load. The wiring device form factor also provides a user accessible front face that is includes one or more switch mechanisms such as levers, dials, slide switches, and other such input control mechanisms that permit a user to vary the power to a load.
Prior to device installation, wiring from the AC power source and wiring to the load(s) are disposed inside the outlet box. The outlet box is usually located proximate to the load being controlled. The device is installed by connecting the wiring inside the outlet box to the appropriate wiring device terminals disposed on the exterior of the wiring device. The power control wiring device is then inserted into the outlet box and attached to the outlet box using one or more fasteners. A cover plate is installed to complete the installation.
Some of the drawbacks associated with conventional power control devices are illustrated by referring to FIG. 1. Conventional device 10 includes a dimmer control knob 12 and switch 14 disposed in a protective frame 16. The protective frame 16 is coupled to mounting strap 20. The frame 16 functions as an alignment mechanism for the cover plate (not shown). The frame 16 extends through the cover plate opening when the device installation is complete. The mounting strap 20 is hidden behind the cover plate.
One drawback to this approach relates to the additional costs and complexity associated with the frame itself. Frame 16 represents an additional part that must be molded or stamped during the fabrication process. Further tooling and/or labor is required to assemble the frame 16, dimmer control 12, and switch 14 to mounting strap 20. Thus, the elimination of a superfluous framing element translates to a device that is easier and cheaper to manufacture. Protective frame 16 also requires a specially sized, non-standard wall plate. This option is less attractive to users because of the difficulty in acquiring a replacement cover plate in the event that it becomes cracked or damaged. Wall plates conforming to the dimensional characteristics defined by the ANSI/NEMA WD6 standard are ubiquitous and easily obtained in an after market transaction.
Another drawback to conventional devices relates to device cleaning and maintenance issues. The protective frame 16 creates dust collecting crevices between the frame and the switch elements, and between the frame and the wall plate. Recessed surface 24 also tends to collect dirt and grime. On the other hand, the crevices and recessed surfaces are difficult to reach and, therefore, difficult to keep clean. Accordingly, unsightly dirt and grime tend to accumulate in the crevices and on the recessed surface 24. To make matters worse, dust particles have a tendency to migrate into the interior of device 10. Those of ordinary skill in the art will appreciate that dust build-up may effect the operation of interior switch components.
Yet another drawback to the conventional device shown in FIG. 1 relates to the lack of a locator lamp or pilot light. A person unfamiliar to the layout of the living space may have difficulty locating the power control wiring device when the space is darkened. The person attempts to "feel" his way around the room in an attempt to locate the dimmer switch. Obviously, this scenario represents a safety hazard. One approach that may be considered incorporates a dedicated lamp into the device housing. Of course, this approach has its own drawbacks. Dedicated lamps of this nature are permanently illuminated. When the lamp burns out, the entire wiring device must be replaced as well.
What is needed is a power control device that includes self aligning user-actuated switching elements that eliminate superfluous framing elements and is easier and relatively less costly to produce. What is also needed is a power control device that employs wall plates that conform to the ANSI/NEMA WD6 standard for wall plates. What is further needed is a power control device that eliminates the cleaning and maintenance issues of conventional devices. Finally, a power control device is needed that includes a modular light assembly that includes a removable light module.

Power control device for an electrical load


A method and apparatus are provided to generate a preamble signal. A peak of each pulse of the preamble signal is synchronized with a sensitivity region of a super regenerative receiver (SRR). The method and apparatus are configured to transmit, to the SRR, a data packet comprising the preamble signal, wherein the data packet is a baseband signal corresponding to the preamble signal.

1. Field
The following description relates to a field of communication systems, and more particularly, to timing synchronization in a wireless communication system.
2. Description of Related Art
Receivers, such as a super regenerative receiver (SRR), are ultra low power radio receivers for low data rate applications. A basic structure of the SRR includes an antenna, a low noise amplifier (LNA), a super regenerative oscillator (SRO), an envelope detector (ED), an automatic gain control (AGC), a quench waveform generator, and a baseband filter (BBF). The operation principle of the SRR is based on a repeated build-up and decay of self-generated oscillations in the SRO having a frequency near radio frequency (RF) signal frequency intercepted by the antenna. The SRR is typically used in low power body area networks, remote control systems, such as garage door openers, robots, model ships, airplanes, short distance telemetry, and wireless security.
In general, frequency selectivity of the SRR is directly affected by an over quenching rate (OQR) of a quench signal. Currently, each data symbol is oversampled by a quench signal operating at a quench rate considerably higher than a data rate. This translates into relatively low frequency selectivity and an equivalent noise bandwidth that is much larger than the signal bandwidth. Thus, the SRR may be easily affected by out-of-band interference. Hence, it is desirable to maintain the OQR as low as possible. However, a higher OQR is needed to ensure that outputs are obtained for each incoming pulse envelope in the SRR. From these outputs, a fractional sample rate is chosen to maximize overall energy capture of an incoming signal. In order to improve an interference rejection, a lower OQR is required, but a higher OQR is necessary to improve the synchronization performance of the SRR.

Timing synchronization system and method of super regenerative receiver based on ultra low power communication


An electrically-conductive and mechanically-compliant joint is formed between a pair of electrical components. The joint is positioned between a lower face of a first electrical component and an upper face of a second electrical component. The Young""s modulus of the joint is less than approximately half that of the Young""s modulus of the electrical components.

The invention relates to surge arresters and other types of electrical power distribution equipment.
Electrical transmission and distribution equipment is subject to voltages within a fairly narrow range under normal operating conditions. However, system disturbances, such as lightning strikes and switching surges, may produce momentary or extended voltage levels that greatly exceed the levels experienced by the equipment during normal operating conditions. These voltage variations often are referred to as over-voltage conditions.
If not protected from over-voltage conditions, critical and expensive equipment, such as transformers, switching devices, computer equipment, and electrical machinery, may be damaged or destroyed by over-voltage conditions and associated current surges. Accordingly, it is routine practice for system designers to use surge arresters to protect system components from dangerous over-voltage conditions.
A surge arrester is a protective device that is commonly connected in parallel with a comparatively expensive piece of electrical equipment so as to shunt or divert over-voltage-induced current surges safely around the equipment, thereby protecting the equipment and its internal circuitry from damage. When exposed to an over-voltage condition, the surge arrester operates in a low impedance mode that provides a current path to electrical ground having a relatively low impedance. The surge arrester otherwise operates in a high impedance mode that provides a current path to ground having a relatively high impedance. The impedance of the current path is substantially lower than the impedance of the equipment being protected by the surge arrester when the surge arrester is operating in the low-impedance mode, and is otherwise substantially higher than the impedance of the protected equipment.
Upon completion of the over-voltage condition, the surge arrester returns to operation in the high impedance mode. This prevents normal current at the system frequency from following the surge current to ground along the current path through the surge arrester.
Conventional surge arresters typically include an elongated outer enclosure or housing made of an electrically insulating material, a pair of electrical terminals at opposite ends of the enclosure for connecting the arrester between a line-potential conductor and electrical ground, and an array of other electrical components that form a series electrical path between the terminals. These components typically include a stack of voltage-dependent, nonlinear resistive elements, referred to as varistors. A varistor is characterized by having a relatively high resistance when exposed to a normal operating voltage, and a much lower resistance when exposed to a larger voltage, such as is associated with over-voltage conditions. In addition to varistors, a surge arrester also may include one or more spark gap assemblies housed within the insulative enclosure and electrically connected in series with the varistors. Some arresters also include electrically-conductive spacer elements coaxially aligned with the varistors and gap assemblies.
For proper arrester operation, contact must be maintained between the components of the stack. To accomplish this, it is known to apply an axial load to the elements of the stack. Good axial contact is important to ensure a relatively low contact resistance between the adjacent faces of the elements, to ensure a relatively uniform current distribution through the elements, and to provide good heat transfer between the elements and the end terminals.
One way to apply this load is to employ springs within the housing to urge the stacked elements into engagement with one another. Another way to apply the load is to wrap the stack of arrester elements with glass fibers so as to axially-compress the elements within the stack.
In one general aspect, an electrically-conductive and mechanically-compliant joint is formed between a pair of electrical components. The joint is positioned between a lower face of a first electrical component and an upper face of a second electrical component. The Young""s modulus of the joint is less than approximately half that of the Young""s modulus of the electrical components.
Embodiments of the joint may include one or more of the following features. For example, the Young""s modulus of the joint may be approximately one-eightieth to one-tenth of the Young""s modulus of the electrical components. More particularly, the Young""s modulus of the joint may be approximately one fortieth of the Young""s modulus of the electrical components. The Young""s modulus of the joint may be between approximately 200,000 psi and 1,600,000 psi and the Young""s modulus of the electrical components may be between approximately 13,000,000 psi and 18,000,000 psi. More particularly, the Young""s modulus of the joint may be between approximately 300,000 psi and 500,000 psi and the Young""s modulus of the electrical components may be between approximately 14,000,000 psi and 17,000,000 psi. Even more particularly, the Young""s modulus of the joint may be approximately 400,000 psi and the Young""s modulus of the electrical components may be approximately 15,000,000 psi.
The joint creates a region between the electrical components that is mechanically more compliant than the components themselves. One reason for the greater compliance within the joint is a Young""s modulus which can be less than half of that of the electrical components. The lower modulus of the joint serves to attenuate or dampen the thermo-mechanical forces generated within the electrical components during operation of, for example, a surge arrester.
The joint may further include an electrically conductive polymer that provides mechanical compliance. The joint also may further include an electrically-conductive, mechanically-compliant metal alloy.
The joint may be between approximately one-sixteenth of an inch thick and one-half of an inch thick. More particularly, the joint may be between approximately one-eighth to three-eighths of an inch thick. Even more particularly, the joint may be approximately one-fourth of an inch thick. The joint may be incorporated in an electrical device.
In another general aspect, an electrically-conductive and mechanically-compliant joint is formed between a pair of electrical components. The joint is positioned between a lower face of a first electrical component and an upper face of a second electrical component. Electrical conductivity is provided by a first layer of an electrically-conductive adhesive adhered to the lower face of the first electrical component and a second layer of the electrically-conductive adhesive adhered to the upper face of the second electrical component. Mechanical compliance is provided by the two layers of electrically-conductive adhesive and by a polymer composite layer that is between the two layers.
Embodiments of the joint may include one or more of the following features. For example, the joint may further include a conductive shunt having a first end, a second end, and a middle section connecting the first end and the second end. The first end is positioned in the first layer of electrically-conductive adhesive, the second end is positioned in the second layer of electrically-conductive adhesive, and the middle section passes through the polymer composite layer.
The polymer composite layer may include a first surface in contact with the first layer of adhesive, a second surface in contact with the second layer of adhesive, a first opening on the first surface, a second opening on the second surface, and a channel passing between the first and second openings. The conductive adhesive of the first and second layers also is in the channel so that it provides an electrically-conductive path between the first and second layers. The polymer composite layer may further include multiple channels passing between multiple first and second openings, with the conductive adhesive in the multiple channels so that they provide electrically-conductive paths between the first and second layers. The polymer composite layer may be electrically-conductive to provide a continuous current path. The polymer composite layer also may be electrically nonconductive, in which case the conductive shunt conducts electricity between the electrical components. The joint may be incorporated in an electrical device.
In another implementation, the polymer composite layer may include an electrically-conductive material. The electrically-conductive material may include a silver alloy and/or a carbon black filler. The polymer composite layer may include an electrically-conductive composite of metal and polymer. The metal may include copper, aluminum or brass, or combinations of those metals. The polymer composite layer also may be a polymer layer having a metal coating on its surfaces. The polymer composite layer may further include electrically-conductive pins passing through the polymer layer and terminating in the adhesive layer. The opposite ends of the conductive pins may be adhered to the upper face of the second electrical component and the lower face of the first electrical component.
In another general aspect, an electrically-conductive and mechanically-compliant joint is formed between a pair of electrical components. The joint is positioned between a lower face of a first electrical component and an upper face of a second electrical component. Electrical conductivity is provided by a first region or layer of an electrically-conductive adhesive adhered to the lower face, a second region or layer of the electrically-conductive adhesive adhered to the upper face, and a metal layer disposed between the first layer and the second layer. Mechanical compliance is provided by the two layers of electrically-conductive adhesive and by the metal layer.
Embodiments of the joint may include one or more of the following features. For example, the metal layer may include a foam metal plate that may be made from aluminum or another metal. The foam metal plate may be a porous metal structure impregnated with an epoxy or an adhesive. The metal layer also may be a deformable metal plate having a first surface defining peaks and valleys and a second opposite facing surface defining peaks and valleys, and may be made from aluminum or copper, or a combination of those and/or other metals. The joint may be incorporated in an electrical device.
In another general aspect, an electrically-conductive and mechanically-compliant joint is formed between a pair of electrical components. The joint is positioned between a lower face of a first electrical component and an upper face of a second electrical component. Electrical conductivity is provided by regions or layers of an electrically-conductive adhesive, and mechanical compliance is provided by alternating regions or layers of an electrically nonconductive adhesive. The electrical apparatus may be incorporated in an electrical device.
In another general aspect, an electrically-conductive and mechanically-compliant joint is formed between a pair of electrical components. The joint is positioned between a lower face of a first electrical component and an upper face of a second electrical component. Electrical conductivity is provided by at least one metal spring adhered on a first end to the upper face and on a second end to the lower face. Mechanical compliance is provided by the metal spring and an adhesive positioned between the upper face and the lower face.
Embodiments of the joint may include one or more of the following features. For example, the adhesive may be an electrically-conductive adhesive that provides electrical conductivity for the joint. A nonconductive adhesive also may be used instead of the electrically-conductive adhesive. The joint may further include additional metal springs adhered on each first end to the upper face of the second electrical component and on each second end to the lower face of the first electrical component. The joint may be incorporated in an electrical device.
In another general aspect, an electrically-conductive and mechanically-compliant joint is formed between a pair of electrical components. The joint is positioned between a lower face of a first electrical component and an upper face of a second electrical component. Electrical conductivity and mechanical compliance are provided by an electrically-conductive shunt having a first end, a second end, and a middle section that connects the first and second ends, a first solder joint that electrically connects the first end to the lower face of the first electrical component, and a second solder joint that electrically connects the second end to the upper face of the second electrical component.
Embodiments of the joint may include one or more of the following features. For example, further mechanical compliance may be provided by an epoxy layer positioned between the lower face and the upper face, and surrounding the electrically-conductive shunt. The shunt may be a spring or multiple springs. The joint may be incorporated in an electrical device.
In another general aspect, an electrically-conductive and mechanically-compliant joint is formed between a pair of electrical components. The joint is positioned between a lower face of a first electrical component and an upper face of a second electrical component. Mechanical compliance is provided by alternating regions or layers of a metal and an epoxy. Electrical compliance is provided by the regions or layers of metal. The alternating regions or layers of the metal and the epoxy are oriented perpendicularly to the upper surface and the lower surface.
Embodiments of the joint may include one or more of the following features. For example, the regions of metal may be regions or layers of a foam metal. The regions or layers of the foam metal may include a porous structure impregnated with an epoxy, an elastomer, or an adhesive, or a combination of these. The joint may be incorporated in an electrical device.
In another general aspect, an electrically-conductive and mechanically-compliant joint is formed between a pair of electrical components. The joint is positioned between a lower face of a first electrical component and an upper face of a second electrical component. Electrical conductivity is provided by at least one metal wire adhered on a first end to the upper face of the second electrical component and on a second end to the lower face of the first electrical component. Mechanical compliance is provided by the metal wire and an adhesive layer positioned between the upper face and the lower face.
Embodiments of the joint may include one or more of the following features. For example, the metal wire may be adhered to the upper face and the lower face by solder. Additional metal wires may be adhered on each first end to the upper face and on each second end to the lower face. The metal wire may be in the form of one or more springs or one or more straps. The joint may be incorporated in an electrical device.
In another general aspect, an electrically-conductive and mechanically-compliant joint is formed between a pair of electrical components. The joint is positioned between a lower face of a first electrical component and an upper face of a second electrical component. Mechanical compliance and electrical conductivity are provided by a first layer of solder adhered to the lower face of the first electrical component, a second layer of solder adhered to the upper face of the second electrical component, and a metal layer between the first and second layers of solder.
Embodiments of the joint may include one or more of the following features. For example, the metal layer also may be a deformable metal plate having a first surface defining peaks and valleys and a second opposite facing surface defining peaks and valleys, and may be made from aluminum or copper, or a combination of those metals. The metal layer also may be a foam metal plate, and the foam metal plate may be a porous structure impregnated with an epoxy or an adhesive. The metal layer also may be a polymer composite layer having a surface metallization of a conductive material. The polymer composite may include a carbon black or a silver alloy filler. The joint may be incorporated in an electrical device.
In another general aspect, an electrically-conductive and mechanically-compliant joint is formed between a pair of electrical components. The joint is positioned between a lower face of a first electrical component and an upper face of a second electrical component. Mechanical compliance and electrical conductivity are provided by an electrically-conductive adherent layer and a multi-component structure.
Embodiments of the joint may include one or more of the following features. For example, the electrically-conductive adherent layer may be an epoxy, a conductive adhesive, or a solder, or a combination of these materials. The joint may be incorporated in an electrical device.
The multi-component structure may include a pair of opposing metal plates, a first outer O-ring positioned between the opposing metal plates, and a second outer O-ring positioned around the first outer O-ring and between the opposing metal plates. A first adhesive is disposed between the opposing metal plates in a space defined between an inner diameter of the second outer O-ring and an outer diameter of the first O-ring. A second adhesive is disposed between the opposing metal plates in a spaced defined by the inner diameter of the first O-ring. The first adhesive may be an electrically nonconductive adhesive and the second adhesive may be an electrically-conductive adhesive.
The multi-component structure may further include a pair of opposing metal plates and a nonconductive layer. Each metal plate may have at least one conductive projection projecting in the direction of the opposing metal plate and being conductively connected to the opposing conductive projection. The nonconductive layer may be positioned between the opposing metal plates and encapsulate the conductive projections. The conductive projections may be connected by a metal wire, or may be directly connected. The nonconductive layer may be, for example, a nonconductive adhesive, a nonconductive epoxy, or a nonconductive polymer composite, or a combination of these materials.
The electrically-conductive and mechanically-compliant joint between a pair of electrical components provides numerous advantages. For example, mechanical compliance may serve to attenuate the mechanical forces generated throughout the electrical components during operation. In this manner, the service duration of the device in which the electrical components are installed will be lengthened because the attenuated forces are less likely to harm the electrical components and joints. The use of nonconductive materials, along with conductive materials, in the joint, may reduce the overall cost of the joint. The electrical conductivity and mechanical compliance of the joint may be tailored by varying the ratio of the quantity of materials used in the joint.
Other features and advantages of the invention will be apparent from the description and drawings, and from the claims.

Compliant joint between electrical components


A method of making ferroelectric film capacitors with sufficient yield for application to ULSI. In a first embodiment, after formation of a first ferroelectric film as the capacitor ferroelectric film, a very thin second ferroelectric film is deposited to fill the cavity portions generated between the crystal grains. This reduces the leakage current and increases the capacitor yield. In second embodiment, the cavity portions are filled with an insulating layer.

In conventional technology, in order to increase the integration degree of the semiconductor device, efforts have been made to reduce the size of the structural elements. For the dynamic memory (DRAM) which requires fine capacitors with high capacitances, application of ferroelectric films with very high specific dielectric constant is attractive. For example, several conventional technologies have been developed (such as that disclosed in P. J. Bhattacharya, et al.: Jpn. J. Appl. Phys., Vol. 32 (1993), pp. 4103-4106).
In the technology disclosed by Bhattacharya, et al., when (Ba,Sr)TiO.sub.3 (referred to as "BST" hereinafter) film is formed on Pt substrate, the crystal of the film is grown in cylindrical form, and a specific dielectric constant as high as about 300 can be guaranteed. When capacitors are formed by using this type of film, it is possible to form capacitors with excellent insulating characteristics. On the other hand, however, many capacitors formed in this way have large leakage current or have initial short-circuit problems. Consequently, it is difficult to guarantee the yield to the level appropriate for mass production of DRAM and other ultra-LSI. Study of the reason indicates that cavities are formed on the intergranular crystal boundaries. One of the purposes of this invention is to provide a type of capacitor and its manufacturing method that can well guarantee the yield to the level appropriate for application in manufacturing ultra-LSI.
Also, for semiconductor devices, in particular, DRAM, capacitors with small areas are needed. In order to realize this type of capacitor, ferroelectric films made of (Ba,Sr)TiO.sub.3, Pb(Zr,Ti)O.sub.3, etc., with high dielectric constants are attractive. However, when these films are used to form capacitors, although the capacitors formed have excellent insulating characteristics, for many capacitors formed in this case, the leakage current is nevertheless high or initial short-circuit problems may take place, and it is impossible to guarantee the yield high enough for application of ULSI such as DRAM. One of the purposes of this invention is to provide capacitors which guarantee a yield sufficiently high for ULSI application and their manufacturing method.

Ferroelectric film capacitor with intergranular insulation