A support assembly for attachment to a substrate, the assembly having a first part comprising a rebated surface to which a sign is securable and a second part having a peripheral wall sized and dimensioned to bound the first part and a continuous facing wall joined to or contiguous with said peripheral wall, the two parts being securable together whereby said continuous facing wall overlies at least part of a peripheral portion of the rebated surface of said first part.

This invention relates to supports, particularly supports for identification plates suitable for use on vehicles, and to signs e.g. identification devices, such as identification plates suitable for use on vehicles.
It is known that numberplates for motor vehicles are stolen. This may be done to. 'clone' a car for use in the pursuit of crime or to avoid paying city congestion charges, for example.
Accordingly, it is desired to provide means such as a support usable with an identification device, for example a vehicle numberplate, which has measures to prevent its theft and/or which is readily identified or identifiable as having been stolen.
Moreover, it is desirable to be able to identify the nature and/or provenance of an article remotely.
In the field of motor vehicle licence plates, solutions have been proposed which enable a person to remotely obtain information concerning the vehicle to which the plate is attached and/or other information pertaining to the driver (e.g. insurance details) and so on.
These passive tags comprise a microwave antenna which is necessarily large to receive an interrogation signal and to receive enough power to activate the circuitry. The large antenna ensures that it may be impossible or at least difficult to form/emboss such a plate.
U.S. Pat. No. 5,621,571 discloses an integrated retro-reflective electronic display comprising a substrate, a ground plane, a dielectric substrate, an antenna network comprising a pair of micro switch patch antennas, and a retro-reflective layer which bears indicia. Conventional retro-reflective layers incorporate a metal layer to retro-reflect light. In this patent, the retro-reflective layer incorporates a disparate metal layer which has enough 'free space' to allow the passage of radio frequency signals (at 915 MHz). Other retro-reflective materials which do not comprise a metal layer are also disclosed. The antenna network is fed via a coaxial connector mounted at the rear of the display through which the network may be connected to any outboard electronic module (for example a power source, memory device, power source and so on).
It is also desired to provide solutions to the theft and/or unwanted removal problem which can ensure that any sign so-removed is unusable thereafter.
In our previously filed International (PCT) patent application PCT/GB02/02773 (published as WO 02/102626 A1) we disclose and claim an identification plate comprising a supporting substrate having a retro-reflective major surface and a transparent sheet material having indicia printed thereon, the transparent sheet material being adhered to the retro-reflective major surface such that the indicia are located in contact with, or at least adjacent to, the retro-reflective major surface, and wherein one or more lines of weakness may be formed in the substrate.
The plate is to be adhered to a surface (for example a body of a car) using sticky pads which would be located either side of the or each line of weakness. If a thief or vandal attempts to remove the plate from the surface to which it is adhered, the plate will snap about the line of weakness. The snapping of the plate causes the transparent sheet to become stretched and/or delaminated from the substrate which makes the plate unsightly and provides an obvious visual indication that the plate has been removed from a surface.
It is an object of the present invention to provide a support which increases the security afforded to identification plates, in particular, although not exclusively for use with signs, e.g. identification plates, provided with lines or areas of weakness.
It is a further object of the invention to provide signs which comprise tamper evident means to indicate, for example, unauthorised or unwanted removal.


A soil release agent for dry cleaning containing a copolymer having (A) a repeating unit derived from a polymerizable monomer having a fluorine atom; and (B) a repeating unit derived from a polymerizable monomer having a siloxane linkage and/or a polymerizable monomer (having no siloxane linkage) having a solubility parameter of 6 to 15 gives excellent soil release property using the dry cleaning.

1. Field of the Invention
The present invention relates to a soil release agent for dry cleaning.
2. Related Art
When a material having a fluoroalkyl group is coated on a solid substance surface, the substance exhibits high water- and oil-repellency due to a remarkably lowered surface energy. In view of this property, a polymer comprising a fluorine-containing polymerizable monomer such as a (meth)acrylate having a fluoroalkyl group is commercially available as a water- and oil-repellent for treating a textile such as clothes in the form of an aqueous dispersion or a solution in an organic solvent. The water- and oil-repellent is used, for example, for clothes such as a raincoat.
However, soil is always adhered to the clothes treated with the water- and oil-repellent, when the clothes are worn. The soil adhered to the clothes cannot be easily removed even if the clothes are washed, since a detergent is repelled at surfaces of the clothes.
When the clothes having the soil are washed in a water at home, the aqueous soil can be easily removed. But, it is known that the oily soil can be removed with difficulty higher than in the case of the clothes which is not treated with the water- and oil-repellent. Accordingly, the water- and oil repellent is not suitable for the clothes to which the soil easily adheres, such as work clothes.
In order to solve the above problem, a soil release agent (also referred to as "SR agent") has been developed and already practically used. In order to remove the oily soil described above, the surfaces of the clothes are treated so that they exhibit a hydrophilic nature together with oil repellency. Accordingly, the soil release agent is prepared by copolymerizing an oil-repellent polymerizable monomer having A fluoroalkyl group with a hydrophilic polymerizable monomer. In the clothes treated with this soil release agent, the oily soil can be easily removed from the clothes in water by household laundering.
The improvement of the soil release agent is being continued so as to enhance an initial soil release property and durability.
In the continuation of the improvement, the soil release treatment for the clothes which are subjected to the dry cleaning is hardly thought and almost no documents describing this are present. The soil release agent having excellent properties and suitable for the dry cleaning is not practically used.


A method of preparing a compound semiconductor crystal is able to dope the crystal with carbon with high reproducibility. The method includes the steps of sealing a carbon oxide gas of a predetermined partial pressure and a compound semiconductor material in a gas-impermeable airtight vessel, increasing the temperature of the vessel to melt the compound semiconductor material sealed in the vessel, and then decreasing the temperature of the vessel to solidify the melted compound semiconductor material to grow a compound semiconductor crystal containing a predetermined amount of carbon. With this method, a compound semiconductor crystal with a carbon concentration of 0.1xc3x971015cmxe2x88x923 to 20xc3x971015cmxe2x88x923 is prepared with high reproducibility.

1. Field of the Invention
The present invention relates to methods of preparing a compound semiconductor crystal and to the compound semiconductor crystals prepared thereby, and particularly to methods of preparing a carbon-containing, compound semiconductor crystal and compound semiconductor crystals obtained thereby.
2. Description of the Background Art
It has been conventionally well known that as for an LEC method using a stainless chamber there is a correlation between the CO gas concentration provided in the chamber and the carbon concentration of a GaAs crystal in a high-pressure Ar gas ambient.
FIG. 3 is a graph of carbon concentration in a GaAs crystal versus CO gas concentration in a LEC furnace found in Advanced Electronics Series I 4 Bulk Crystal Growth Technology, Keigo Hoshikawa, BAIFUKAN, p.184, Fig. 7.22. FIG. 3 shows that carbon concentration in a GaAs crystal and CO gas content in the LEC furnace are correlated by a straight line. In the LEC method, the correlation represented in the graph is applied to the adjustment of carbon concentration in a GaAs crystal. The carbon concentration in a GaAs crystal can be controlled by adjusting the CO gas content in the ambient gas using a CO gas cylinder and an Ar gas cylinder for dilution connected to the stainless chamber.
FIG. 4 shows an exemplary GaAs crystal growth equipment for the LEC method disclosed in Japanese Patent Laying-Open No. 1-239089. Referring to FIG. 4, Japanese Patent Laying-Open No. 1-239089 discloses a method of preparing a single crystal of compound semiconductor by placing in a predetermined gas ambient a raw-material housing portion housing a raw-material melt, detecting at least the concentration of one of H2, O2, CO2 and CO corresponding to components of the ambient gas, and controlling the detected concentration of a component at a predetermined value to keep over the entirety of an ingot a predetermined concentration of a residual impurity mixed into a resulting single crystal.
This method can, however, not be applied in preparing a compound semiconductor crystal in a gas-impermeable airtight vessel incapable of supplying a gas from outside the airtight vessel, such as a quartz ampoule.
Japanese Patent Laying-Open No. 3-122097 discloses a method of preparing a GaAs crystal in a quartz ampoule wherein a carbon source is arranged internal to the ampoule and external to a crucible in fluid communication with a polycrystalline compound provided as a raw material to allow the GaAs crystal to be doped with carbon. xe2x80x9cFluid communicationxe2x80x9d means a free flow of vapor and heat between the inside and outside of the crucible which allows carbon to be transferred into the crucible and thus to a melt. In accordance with the method, a carbon disk is arranged on an opening of a cap. It discloses that the ingots of various doped levels can be provided by varying the amount of carbon arranged external to the opening and/or the crucible.
With this method, however, a large amount of carbon source is placed above the melt. Thus fine powder of carbon falls thereon and can thus vary the carbon concentration thereof. Particularly, the controllability can be poor at a slight carbon concentration corresponding to a level of 0.1xc3x971015 cmxe2x88x923 to 2xc3x971015 cmxe2x88x923.
Japanese Patent Laying-Open No. 64-79087 discloses a method of preparing a single crystal of GaAs doped with carbon to reduce dislocation, using a reactor or a boat for crystal growth at least partially formed of carbon. It discloses that when a graphite boat is used, a part of the carbon boat changes into a gas (CO or CO2) due to oxygen derived from a small amount of As2O3, Ga2O or the like remaining in the quartz reactor and the gas is thus added to the single crystal of GaAs in synthesis reaction or in single-crystal growth.
In accordance with this method, however, it is difficult to control the carbon concentration in the crystal due to the difficulty of controlling the amount of As2O3, Ga2O or the like remaining in the quartz reactor. In particular, the controllability can be poor at a slight carbon concentration corresponding to a level of 0.1xc3x971015 cmxe2x88x923 to 2xc3x971015 cmxe2x88x923.
Japanese Patent Laying-Open No. 2-48496 discloses a method of preparing a Cr-doped, semi-insulating GaAs crystal wherein a quartz boat or a quartz crucible is used to grow the crystal under the existence of nitrogen oxide or carbon oxide. It discloses that when a GaAs crystal is grown under the existence of nitrogen oxide or carbon oxide, the oxide serves as an oxygen doping source to reduce the Si concentration of the grown crystal so that a semi-insulating crystal is reliably provided.
However, this method contemplates control of oxygen concentration and does not describe control of carbon concentration.
One object of the present invention is to provide a method of preparing a compound semiconductor crystal allowing the compound semiconductor crystal to be doped with carbon in high reproducibility, and a compound semiconductor crystal prepared thereby.
In one aspect of the present invention, a method of preparing a compound semiconductor crystal includes the steps of sealing carbon oxide gas of a predetermined partial pressure and a compound semiconductor provided as a raw material in a gas-impermeable airtight vessel, increasing the temperature of the airtight vessel to melt the compound semiconductor material sealed in the airtight vessel, and thereafter decreasing the temperature of the airtight vessel to solidify the melted compound semiconductor material to grow a compound semiconductor crystal containing a predetermined amount of carbon.
The carbon oxide gas includes at least one type of gas selected from the group consisting of CO gas and CO2 gas.
In growing the crystal, preferably the melted compound semiconductor material is at least partially kept in contact with boron oxide (B2O3).
In growing the crystal, more preferably the melted compound semiconductor material has its upper surface entirely covered with boron oxide (B2O3).
Preferably, the boron oxide (B2O3) has a water content of no more than 300 ppm, more preferably no more than 100 ppm.
Preferably, variation of the water content of the boron oxide (B2O3) is controlled to fall within a range from +20% to xe2x88x9220%.
In accordance with the present invention, the carbon oxide gas sealed in the airtight vessel preferably has a partial pressure of 0.1 to 100 Torr at 25xc2x0 C.
In accordance with the present invention, carbon oxide gas is preferably sealed in an airtight vessel according to an expression:
CCARBON=axc3x97P0.5xe2x80x83xe2x80x83(1),
wherein CCARBON (cmxe2x88x923) represents carbon concentration in a compound semiconductor crystal, P (Torr) represents partial pressure of the carbon oxide gas, and a represents any coefficient.
In expression (1) coefficient a preferably ranges from 0.25xc3x971015 to 4xc3x971015 cmxe2x88x923/Torr0.5, more preferably 0.5xc3x971015 to 2xc3x971015 cmxe2x88x923/Torr0.5.
In accordance with the present invention, preferably the step of subjecting the airtight vessel to a vacuum heat treatment is also provided before the step of sealing carbon oxide gas in the airtight vessel.
The vacuum heat treatment is preferably provided at a temperature of no more than 350xc2x0 C.
In accordance with the present invention, at least the internal wall of the airtight vessel and at least the outer surface of the contents of the airtight vessel other than the compound semiconductor material and the boron oxide are preferably formed from a material which does not contain carbon.
The material which does not contain carbon includes at least one material selected from the group consisting, e.g., of quartz, silicon nitride, boron nitride, pyrolytic boron nitride and alumina.
In accordance with the present invention, the gas-impermeable airtight vessel can at least partially be formed from quartz.
Preferably, the portion formed from quartz has a thickness of no less than 1.5 mm.
In growing the crystal, preferably the portion formed from quartz is controlled to have a temperature of at most 1270xc2x0 C.
In accordance with the present invention, in growing the crystal a space behind a raw-material melt of melted compound preferably has its most heated portion and its least heated portion with a temperature difference of no more than 300xc2x0 C. therebetween.
In accordance with the present invention, the space behind the raw-material melt is preferably larger, more preferably no less than twice larger in volume than the space on the side of the raw-material melt.
A method of preparing a compound semiconductor crystal in accordance with the present invention is applicable to preparing a compound semiconductor crystal of GaAs.
In another aspect, the present invention provides a compound semiconductor crystal prepared in accordance with the above-described method of preparing a compound semiconductor crystal, having a carbon concentration of 0.1xc3x971015 cmxe2x88x923 to 20xc3x971015 cmxe2x88x923.
In accordance with the present invention, the compound semiconductor includes GaAs.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

Method of preparing a compound semiconductor crystal


Example embodiments are directed toward a method of decoding a multi-view video signal using a video decoding apparatus including using a global motion vector of a non-anchor current picture in a current view to determine a corresponding block. A reference block in the current view is then determined using motion information of the current block that is generated from motion information of the corresponding block. A pixel value of the current block is predicted using the reference block in order to raise efficiency in signal processing of the multi-view video signal.

Compression coding means a series of signal processing techniques for transmitting digitalized information via a communication circuit or storing the digitalized information in a form suitable for a storage medium. As targets of compression coding, there are audio, video, characters, etc. In particular, a technique for performing compression coding on video is called video sequence compression. A video sequence is generally characterized in having spatial redundancy or temporal redundancy. Moreover, there is a multi-view video sequence belonging to one of fields for 3-dimensional (3D) video processing that provides multi-views to a user using at least one or more cameras.

Method and apparatus for processing a signal


A ferroelectric motor comprises a single layer of ferroelectric material electrically excited by an array of electrical contacts and an electrical excitation source for supplying phased electrical signals to the contacts thereby creating a travelling wave of mechanical deformation in the ferroelectric layer and actuating an actuator. In alternative embodiments of the invention, the actuator may be linear or rotary. The motor may be fabricated on a single integrated circuit die, in which case the layer of ferroelectric material may be a thin film of PZT. In other embodiments a motor may comprise two dies which are sandwiched together by wafer to wafer bonding. Portions of a die may be removed to permit a linear actuator to project beyond the die.

This invention relates to silicon-based microfabricated motors, and particularly to motors for miniature robots.
Several groups are working on integrated circuit motors or actuators. There have been some early successes, but hurdles still remain. Most of the existing microfabricated structures were developed to produce microsensors. Pressure sensors, chemical sensors and accelerometers are just a few of the wide variety of microsensors now commercially available which convert other variables to electrical signals in order to transduce some physical phenomenon into information. Due to the fact that these sensors can be both mass produced and fabricated with on-chip signal processing, they are rapidly finding homes in such places as the automobile and appliance industries.
The basic technology which makes it possible to fabricate freely moving components on chips is termed silicon micro-machining. Micro-machining processes etch structural shapes in silicon for mechanical purposes. Mechanical structures such as cantilever beams and bridges have been etched in silicon in sizes on the order of a few tens of microns.
Known microfabricated motors rely on variable capacitance forces to create motion. A typical microfabricated motor is the variable capacitance micromotor, which uses capacitive forces to cause a rotor to slide around a bearing. In this motor, friction between the bearing and rotor creates losses.
Other, large scale motors have been designed using piezoelectric phenomena for mechanical force. For example, macroscopic travelling wave motors made out of bulk ceramic PZT have been designed with very high efficiency, and some even appear commercially (see Inaba et al., "Piezoelectric Ultrasonic Motor", Proceedings of the 1987 IEEE Ultrasonics Symposium, pp. 747-756, and Kumada, "A Piezoelectric Ultrasonic Motor", Japanese Journal of Applied Physics, Vol. 24 (1985) Supplement 24-2, pp. 739-741).
Travelling wave motors also have inherent gear reduction due to the rectification of high frequency vibratory motion into continuous unidirectional motion. The resulting high power, low mass, low speed motors are ideal for robotic applications as complex gearing can be omitted.
Of the thirty-two different crystal classes, twenty-one have lattice formations with an inherent asymmetry. Twenty of those twenty-one crystals exhibit piezoelectric properties, which means that application of a voltage across the material causes a mechanical deformation and, conversely, stressing the material produces an electrical signal.
Of the twenty substances that have piezoelectric attributes, ten contain an electric dipole moment in the unstrained condition, which leads to pyroelectric characteristics. A pyroelectric material creates an electrical signal when the crystal is exposed to a change in temperature.
Some of the ten pyroelectric materials also display ferroelectric traits. A ferroelectric material can have its polarization dipole reoriented in direction through the application of a strong electric field. After the electric field is removed, the crystal retains the polarization direction, effectively acting as a solid-state switch.
Ferroelectrics, then, being a subset of pyroelectrics and piezoelectrics, contain attributes of all three. In addition, ferroelectric materials are characterized by having very high dielectric constants.
Piezoelectric, pyroelectric, and ferroelectric phenomena have been used in a wide variety of applications. Materials that are predominantly piezoelectric are often used in items such as speakers, touch sensors or microphones and can be found in bulk ceramic or thin film form. Ceramics with large pyroelectric coefficients are used in applications which sense changes in infrared energy such as burglar alarms or night-vision scopes. Recently, some materials which exhibit ferroelectric properties have been produced in thin film form and incorporated into memory chips to create non-volatile random access memories.
Known robots are designed to individually complete such tasks as window washing, automated manufacturing, or other physical duties which are too hazardous, difficult, or mundane for humans to perform. It has been found that the physical strength of robots can easily exceed that of human beings, but the programming of such robots to perform all but the most repetitive tasks has proven difficult.
Known robot designs are quite expensive, owing mostly to the expense of suitable mechanical actuators and the attendant power systems.


An apparatus for inspecting the characters/numbers of a negotiable instrument, the apparatus being provided with: cameras (124) for imaging the character/number sequence (1b) printed on each design on large-size printed matter (1) on which a plurality of designs of the negotiable instrument are printed; and a character/number inspection device (10) for determining the suitability of the characters/numbers printed on each negotiable instrument on the basis of the image data imaged by the cameras (124), wherein the character/number inspection device (10) determines the suitability of the character/number sequence (1b) in a cut segment (1a) on the basis of a plurality of determination standards set in accordance with the position of the cut segment (1a) on the large-size printed matter (1).

Printed securities products such as bank notes (hereinafter, referred to as securities) are obtained by simultaneously printing a plurality of securities patterns on a single printing sheet (large-size printing product) in a layout of six rows by five columns or the like by what is called step and repeat imposition printing, and further by printing characters and numbers for management during production (serial number: e.g. a combination of alphabetical letters and Arabic numerals) on each pattern by means of a numbering and imprinting machine. Hereinafter, a pattern with characters and numbers printed thereon will be referred to as a small piece.
The printed characters and numbers are checked by a number checking apparatus as for whether the characters and numbers are printed so accurately that they look natural when a person sees them, whether the characters and numbers are printed at an accurate position relative to a reference mark (=reference mark), whether the characters and numbers are printed in a proper sequential order so that they can be easily managed, and so on. Thereafter, the large-size printing product is cut into small pieces and used as securities.
A numbering and imprinting machine described in, for example, Patent Document 1 has heretofore been known as a numbering and imprinting machine equipped with a number checking apparatus as mentioned above.

Apparatus for inspecting characters/numbers of negotiable instrument, and method for inspecting characters/numbers of negotiable instrument


The present invention provides a method and an apparatus for improving the etch uniformity across a substrate during a plasma etch process that employs the use of an inductively coupled plasma helical inductor. The plasma apparatus comprising a vacuum chamber, a support member in the vacuum chamber for holding the substrate, an etchant gas supply for providing an etchant gas to the vacuum chamber, an exhaust in fluid communication with the vacuum chamber, an RF power source and a helical inductor disposed around or near a portion of the vacuum chamber. A sensor is provided for measuring a process attribute to generate a signal to a controller that then controls a mechanism that varies the position of the helical inductor so that the uniformity of the plasma etch is improved.

Dry etching is a well established technology used in the manufacture of silicon-based semiconductor devices. It is also widely used in the manufacture of non silicon-based products (e.g., GaAs, InP materials) and non semiconductor products (e.g., micro-electro-mechanical-systems (MEMS) devices, hard drive head components, photomasks). All of these applications have a common requirement that a material is etched from a substrate, usually in a pattern defined by a mask such as photoresist or other non erodeable material. In some cases, the substrate itself is etched. To ensure that devices or features located at different locations within the substrate have the same characteristics, it is important that the etch is uniform over the whole area of the substrate. The level of etch uniformity required depends upon the specific application, but it is a general trend that as devices become more complex, the uniformity requirements become more stringent. Thus, although etch uniformities of 5% have previously been acceptable, there is becoming a need for uniformities of 1% or better.
An example is found in the manufacture of Alternating Aperture Phase Shift Masks (AAPSM) where it is necessary to etch a specific depth into a quartz photomask. This etch is required to create a 180° phase shift which, for the 65 nm lithography node, must be accurate to +/−1° of phase angle. This requires that the etched depth is uniform over the whole mask area to approx +/−0.5% (1% range).
High density plasma sources such as Inductively Coupled Plasma (ICP) have become widely accepted in dry etching. Such sources have the advantage of separate plasma density and ion energy control, and efficient plasma production at low pressure (<10 mT) where diffusion ensures good plasma uniformity.
However, even such sources cannot achieve uniformity at the 1% level. The plasma generation is degraded by minor variations introduced during the source construction, by application of the Radio Frequency (RF) and from interactions with the rest of the reactor. The majority of these variations can generally be divided into two classes, symmetric (e.g., radial) and asymmetric (e.g., side-to-side) variation. For ion driven processes (e.g., the Alternating Phase Shift Masks (AAPSM) quartz etch) these asymmetries result in an etch non-uniformity which is undesirable. A number of groups have proposed solutions to the radial non uniformity observed in inductive reactors. These solutions include inserts that physically displace the plasma (see Hieronymi et al. U.S. Pat. No. 5,391,281 and Johnson et al. U.S. Pat. No. 6,339,206), the use of multiple ICP coils (see Barnes U.S. Pat. No. 6,617,794 for example) and for spiral coils, modifying the axial spacing between the spiral coil and the dielectric plate (see Barnes U.S. Pat. No. 6,617,794 and Hashimoto U.S. Pat. No. 6,096,232).
While the methods described in the prior art improve the symmetric uniformity of the plasma, there is a need for an ICP source which can correct for asymmetric etch uniformity.
A number of groups have attempted to correct asymmetric non-uniformity. Yoshida et al. (U.S. Pat. No. 5,690,781) disclose a spiral coil ICP that is movable in the direction parallel to the main planar surface of the dielectric plate by a motor to control the distribution of the etching rate that is not symmetric about the center of the wafer. Yoshida et al. teach that the optimum location of the coil is when the center of gravity of the coil is matched with the axial center of the chamber. Yoshida et al. do not consider the case of radial coil movements for a helical ICP.
Barnes (U.S. Pat. No. 6,617,794) also discusses adjusting the position of ICP coils relative to the dielectric chamber wall. Barnes teaches axial movement of multiple coils that are located concentrically about the vertical axis of the processing chamber. Barnes does not consider radial coil movements to improve plasma density or etch rate uniformity
Becker et al. (U.S. Pat. No. 6,531,031) disclose positioning a helical ICP coil such that the coil and the dielectric cylinder are not concentric. Becker et al. teach positioning the "hot" ends of a helical coil that is powered at both ends at a maximal distance from the ceramic reactor vessel. In this manner, the coil opposite the powered ends is in contact with the ceramic vessel (i.e., the ceramic reactor vessel is tangent to the coil at the location diametrically opposed to the powered coil ends). Becker et al. do not teach a coil that is adjustable along any radial direction in order to correct for an asymmetric etch non-uniformity.
Hashimoto (U.S. Pat. No. 6,096,232) teaches the use of process feedback to adjust the axial distance of a spiral inductor from a dielectric window. Hashimoto does not consider radial coil adjustments. In addition, Hashimoto does not contemplate the case of helical inductors.
Tanaka et al. (U.S. Pat. No. 6,210,539) disclose moving an ICP coil in the axial direction to improve the uniformity in sputtering systems. Tanaka et al. teach positioning the coil within the reactor chamber, at or below the plane of the substrate, to improve uniformity. Tanaka et al. do not consider adjusting the coil in the radial direction to improve asymmetric etch non-uniformity.
Holmann et al. (U.S. Pat. No. 6,217,718) teach tilting an ICP coil located within the plasma reactor relative to the substrate plane in order to affect asymmetric non-uniformity. Holmann et al. do not disclose tilting an externally located inductor.
Therefore, there is a need for improving the etch uniformity in an ICP plasma reactor having a helical inductor.
Nothing in the prior art provides the benefits attendant with the present invention.
Therefore, it is an object of the present invention to provide an improvement which overcomes the inadequacies of the prior art devices and which is a significant contribution to the advancement of the semiconductor processing art.
Another object of the present invention is to provide an apparatus for etching a substrate comprising: a vacuum chamber; a support member in said vacuum chamber for holding the substrate; an etchant gas supply for providing an etchant gas to said vacuum chamber; an RF power source; a helical inductor disposed around or near a portion of said vacuum chamber, said helical inductor inductively coupling energy to said etchant gas to form a plasma in said vacuum chamber; an exhaust in fluid communication with said vacuum chamber; and a mechanism for varying the position of said helical inductor.
Yet another object of the present invention is to provide an apparatus for etching a substrate comprising: a vacuum chamber; a support member in said vacuum chamber for holding the substrate; an etchant gas supply for providing an etchant gas to said vacuum chamber; an RF power source; a helical inductor disposed around or near a portion of said vacuum chamber, said helical inductor inductively coupling energy to said etchant gas to form a plasma in said vacuum chamber; a sensor for measuring a process attribute; a mechanism for varying the position of said helical inductor; a controller connected to said sensor and said mechanism; and an exhaust in fluid communication with said vacuum chamber.
Still yet another object of the present invention is to provide a method for improving plasma uniformity in a plasma etching process, the method comprising: placing a substrate in a vacuum chamber; subjecting the substrate to an inductively coupled plasma etch process within said vacuum chamber; adjusting the position of a helical inductor; and removing the substrate from the vacuum chamber.
Another object of the present invention is to provide a method for improving plasma uniformity in a plasma etching process, the method comprising: placing a substrate in a vacuum chamber; subjecting the substrate to an inductively coupled plasma etch process within said vacuum chamber; measuring a process attribute; adjusting the position of a helical inductor based on said measuring step; and removing the substrate from the vacuum chamber.
The foregoing has outlined some of the pertinent objects of the present invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.

Method and apparatus to improve plasma etch uniformity


An imaging device includes a photoreceptor portion including a plurality of photoreceptors arranged in an array, a microlens array including a plurality of microlenses, and a light shielding layer placed between the photoreceptor portion and the microlens array. The light shielding layer has apertures located corresponding to the plurality of photoreceptors. An optical relationship of an actual length d1 of an aperture width of the apertures on a side of the photoreceptors, an actual length p of a distance between adjacent microlenses, an equivalent air length t0 of a distance between vein and a top of the microlenses, and an equivalent air length t1 of a thickness between the top of the microlenses and an aperture position of the apertures on the side of the photoreceptors satisfies:

1. Field of the Invention
The present invention relates to an imaging device and a biometrics authentication apparatus.
2. Description of Related Art
Biometric authentication technology using human body characteristics such as fingerprints, irises and blood vessel patterns receives attention as a new security system. The biometric authentication technology offers convenience because there is no need to take along unlike a key or the like. Further, because there is also no possibility of loss unlike a key or the like, the risk of a threat to safety and security due to theft or the like is low.
Particularly, an authentication method using blood vessel patterns in a human finger or the like is not associated with criminal investigation unlike the method using fingerprints and does not require the application of light to eyeballs unlike the method using irises. Thus, the use of blood vessel patterns reduces the possibility that a person who undergoes the authentication process feels psychologically stressed. Further, because the authentication method using blood vessel patterns utilizes the information in vivo, the possibility of forgery is low.
The biometric authentication using a blood vessel pattern in a human finger is under development. Typically, a light source which applies a near-infrared ray to a finger and a camera which captures an image of a near-infrared ray passing through the finger are placed. An optical filter which transmits a near-infrared ray is attached to the camera. Upon biometric authentication, a finger is placed in the path of a near-infrared ray from the light source, and an image of the finger is captured by the camera. Although a near-infrared ray passes through a muscle, fat, bone and so on in vivo, it is absorbed by hemoglobin in the blood and a pigment component such as melanin.
Therefore, although an image which is captured by the camera is shown as white with transmitted light, a blood vessel portion is shown as black. The captured blood vessel pattern image is then checked against registered blood vessel patterns, thereby performing biometric authentication (cf. Japanese Unexamined Patent Application Publication Nos. 2005-312749 and 2005-71118).
There is a growing demand for a smaller and thinner biometric authentication apparatus for carrying out such biometric authentication. As an imaging device which is used in a biometric authentication apparatus, a monocular reduction optical system with the use of reduced imaging of a single or a plurality of lenses has been used. However, there is a limit to the size and thickness reduction for its lens structure.
Thus, there is an attempt to apply a compound-eye optical system which combines a microlens array with a plurality of photoreceptors to a biometric authentication apparatus. An imaging device with a compound-eye optical system is described in Japanese Unexamined Patent Application Publication No. 3-157602, for example.
Japanese Unexamined Patent Application Publication No. 3-157602 discloses an imaging device that includes a microlens array, a photoreceptor portion (image sensor) which is placed opposite to the microlens array, a light shielding layer (light shielding spacer) which is placed between the microlens array and the photoreceptor portion, and a plurality of apertures (translucent holes) having a light absorbing surface on at least part of its wall surface, which are placed between the microlens array and the photoreceptor portion.
FIG. 19 is a vertical sectional view of an imaging device disclosed in Japanese Unexamined Patent Application Publication No. 3-157602. According to the technique disclosed therein, a light shielding layer (light shielding spacer) 20A having a plurality of cylindrical apertures (translucent holes) 30A is placed between a microlens array (lens array plate) 50A and a photoreceptor portion (contact image sensor) 10A. The plurality of cylindrical apertures 30A are formed corresponding to the positions of microlenses (minute lenses) 51A and photoreceptors (photo-detectors) 11A.
A black coating which functions as a light absorbing surface is applied to the inside of each aperture 30A. With such a configuration, the technique disclosed in Japanese Unexamined Patent Application Publication No. 3-157602 can reduce the disadvantages of a compound-eye optical system. Specifically, it prevents the superposition of noise on a received signal at the photoreceptor 11A due to crosstalk, which is, entrance of light from a microlens 51A different from a corresponding microlens 51A into the photoreceptor 11A.
The technique disclosed in Japanese Unexamined Patent Application Publication No. 3-157602 allows suppression of crosstalk from an adjacent microlens 51A. However, the photoreceptor 11A receives light from the range of an area B. An area A is a desired imaging area above the microlens 51A which corresponds to the microlens 51A. The area B includes the area A and it is wider than the area A. Light from an area that excludes the area A from the area B becomes a noise component. Thus, if light from the area B enters the photoreceptor 11A, the quality of a signal which is generated in the photoreceptor 11A is degraded, causing an image on an obtained picture to appear blurred.
Further, if a gap between the microlens array 50A and the photoreceptors 11A is narrowed, the area B becomes wider. This results in further degradation of the quality of a signal from the photoreceptor 11A. This is a serious problem in reducing the thickness of an imaging device.

Imaging device and biometrics authentication apparatus

Abstract: 1.36      ×      t                                      1        p    ≤      d                          1    ≤                    2.4        ×        t                                                  1            p        +                            p          ×          t                                                              1                          t                                                              0                    .


This large magnification factor zoom lens includes, in an order arranged from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power. The third lens group includes, in an order arranged from the object side, a positive lens, a positive lens, a positive meniscus lens having a larger radius of curvature on an image surface side, and a negative lens. The positive lens has an aspherical surface on an object side.

1. Field of the Invention
The present invention relates to a compact large-magnification-factor zoom lens having a wider angle of view.
2. Description of the Related Art
Recently, design techniques and manufacturing techniques for optical equipments are advanced and downsize of zoom lenses and increase in magnification factors have become possible. Accordingly, a wide variety of large magnification factor zoom lenses have been proposed (for example, Japanese Patent Laid-Open Publication Nos. 2000-89117, 2002-236255, 2003-241097, 2005-331697, and H11-174327).
Zoom lenses described in the above Patent documents include a first through a fourth lens groups having refractive powers of positive, negative, positive, and positive, respectively, in an order arranged from an object side, thereby achieving an increased magnification factor.
Particularly, the zoom lens described in Japanese Patent Laid-Open Publication No. 2005-331697 has such a feature that, when the zoom lens is used in a digital single-lens reflex camera including an image sensor in an APS-C size installed therein, the zoom lens can ensure a back focus equivalent to that typically possessed by a conventional single-lens reflex camera for a 35 millimeters (mm) film.
Further, the zoom lens described in the Patent document 5 is configured to have six lens groups including a first lens group having a positive refractive power and a second lens group having a negative refractive power in an order arranged from an object side, thereby achieving an increased magnification factor.
Unlike conventional film single-lens reflex cameras, in digital single-lens reflex cameras, attachment of foreign matters onto an imaging device such as a charge-coupled device (CCD) leads to considerable deterioration of a photographed image. To prevent attachment of foreign matters onto imaging devices by allowing the decreased number of times of lens exchange, zoom lenses of large magnification factors are developed. However, such zoom lenses have photographing angles of view of about 75 degrees and F-numbers of about 3 to 4, and zoom lenses having magnification ratios exceeding 13 have not been proposed.
Meanwhile, increased magnification ratios of zoom lenses lead to increased displacements of lens groups as well as increased variations of aberrations, thereby causing a problem that aberration corrections are made difficult over the entire magnification ranges, respectively. To solve this problem, methods are conventionally adopted to conduct aberration correction by decreasing refractive powers of lens groups of a zoom lens, or to conduct aberration correction by forming a surface(s) of one(s) of lenses constituting a zoom lens as an aspherical surface(s). However, decreased refractive powers of the lens groups result in increased displacement of the lens groups upon magnification change and thus in a complicated cam mechanism that supports the zoom lens, thereby newly causing a problem of an increased dimension of the zoom lens in a radically outward direction thereof.
In the zoom lenses described in Japanese Patent Laid-Open Publication Nos. 2000-89117, 2002-236255, and 2003-241097, aspherical surfaces are introduced and third lens groups are each constituted of three lenses, thereby conducting aberration corrections without increasing the number of lenses. According to such configurations, aberration corrections can be conducted without substantial problems, insofar as magnification ratios are limited to about 7 to 10. However, the configurations each suffer from failure of correction of spherical aberrations caused in a first lens group and a second lens group, respectively, at a telephoto end, when the magnification ratio is set to be about 13.
Furthermore, the zoom lens described in Japanese Patent Laid-Open Publication No. 2005-331697 has a magnification ratio of about 7, so that the magnification of the third lens group is rarely made to be about −1 due to magnification change even by decreasing a refractive power of the third lens group. However, if the magnification ratio is increased to about 13 while the configuration is unchanged, a focal length where a magnification is made to be −1 is included, and aberration correction at the third lens group is brought to a limit, thereby causing a problem of deteriorated optical performance of the zoom lens as a whole.
Also, the zoom lens described in the Japanese Patent Laid-Open Publication No. H11-174327 has the same problem as those zoom lenses described in the other Patent documents.
In any case, it is impossible to sufficiently correct aberrations caused at the first and the second lens groups at a telephoto end, when magnification ratios are made to be 13 or more in the configurations of the zoom lenses described in the above Patent documents. This rather leads to increased sensitivities of the third lens groups to aberrations, respectively, thereby causing a problem that even a slight manufacturing error is not allowed.


Expanded and extruded polyolefin foams are obtained using environmentally benign non-VOC methyl formate as a blowing agent. The blowing agent can be a blend further including at least one co-blowing agent, preferably an environmentally friendly species (e.g., non-VOC), which is either a physical co-blowing agent (e.g. an inorganic agent, a hydrocarbon, a halogenated hydrocarbon, a hydrocarbon with polar, functional group(s) or any combination thereof), or a chemical co-blowing agent, or combinations thereof. The blowing agent blend can include any combination of methyl formate and one or more co-blowing agents. The polymer foam can include polyethylene, polypropylene or a combination thereof. The methyl formate-based blowing agent blends produce stable foams for various applications, including containers, packaging systems, as well as for insulation and protective cushioning. Processes for the preparation of such foams are also provided.

Foams made from alkenyl aromatic polymers (e.g, polystyrene) or polyolefin polymers (e.g. polyethylene and polypropylene) have found extensive use, particularly as packaging, protective, and insulating materials. Polyolefin foams are particularly advantageous due to their tolerance to high service temperatures. Polyolefin foams are commonly manufactured as expanded beads, extruded sheets or extruded boards. The difference between the expanded and extruded foams is that the extruded foams, in the form of continuous sheets or boards, are made in a single-step process; whereas, expanded foams, in the form of discrete, small-size pieces, are made in a multi-step process. Thus, the dimensions of expanded foam are much smaller than those of extruded foam. Furthermore, the expanded foams do not necessarily have to be in the form of beads or peanuts, but can also be made from pellets, rods, platelets, thin sheet or film. For the sake of convenience, the term "bead" or "pellets" will be used throughout this application to imply other shapes in which small, discrete particles of the polymer resin can be used to make expanded foams.
Generally, polyolefin foams in the form of beads or sheets having a thickness of less than about one-half inch can be used to make packaging materials such as containers (cups, bowls, clamshells, picnic chests) for hot or cold beverages or food whereby the beads are fused or the sheet is thermoformed in a mold to form the packaging material of a desired shape. Such foams are also used as protective and cushioning materials for transportation of delicate or shock sensitive articles whereby the foam beads can be used as loose fill dunnage material and thin sheets can be used to provide protective wrapping.
Packaging and insulation foam products with a thickness greater than about 0.5 inch are called planks or boards. Such foam boards are produced in the desired shape and size by direct extrusion and cutting if needed, or by fusing the expanded foam beads. The foam boards can be used for protective packaging by die-cutting the boards to various shapes, for insulation, for dissipating mechanical energy as in automotive parts, or for cushioning floats. It is desirable that the polyolefin foams used in such diverse applications be dimensionally stable; this characteristic is even more desirable for planks or boards.
These and other polymer foams are commonly made using a continuous process where a blowing agent laden molten resin is extruded under pressure through an appropriate die into a lower pressure atmosphere. Alternatively, a batch or staged process can be used, where small polymer beads (also called particles or pellets) are impregnated with blowing agent and then expanded by heating rapidly to a temperature near or above the glass-transition or crystal-melt temperature of the polymer-blowing agent system, or subjected to an external compressive stress at a temperature up to the glass-transition or crystal-melt temperature of the polymer-blowing agent system. Presently, physical blowing agents more commonly used for making polyolefin foams are hydrocarbons, chlorinated hydrocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, or combinations thereof. Hydrocarbons with three or more carbon atoms are considered volatile organic compounds (VOCs) that can lead to formation of smog. Furthermore, some halogenated hydrocarbons are either VOCs or may have high ozone depletion potential (ODP) or global warming potential (GWP), or may be hazardous air pollutants (HAPs) and, at times, may fall into more than one of these categories. Therefore, the use of hydrocarbon and halogenated hydrocarbon blowing agents for preparing polymeric foams is not preferred environmentally and imposes many limitations on the manufacturing process, thus complicating and significantly increasing the cost of manufacturing. For example, polyolefin foams (beads or sheets) are generally made using VOCs such as butanes or compounds such as halogenated hydrocarbons that are HAPs and/or may have high ODP and/or may have high GWP. It is therefore desirable to minimize or eliminate altogether the use of such compounds as blowing agents for preparing polyolefin foams.
Methyl formate is classified as a non-VOC (Federal Register, Volume 69, Number 228, Nov. 29, 2004), is non-HAP, has zero ODP, and negligible GWP. U.S. Pat. No. 6,753,357 to Kalinowski et al., which is incorporated in its entirety herein by reference thereto, describes the use of methyl formate to produce stable, rigid isocyanate/polyol based polyurethane foams. It is noted, however, that such polyurethane foams are thermoset, so as to be made via a cross-linking and curing process. The dimensional stability or instability imparted to the final polyurethane foam product by the nature of the blowing agent therefore is quite different than in the case of polyolefin foams.
U.S. Pat. No. 3,407,151 to Overcashier et al., which is incorporated in its entirety herein by reference thereto, is directed to the production of expanded or expandable thermoplastic materials, particularly crystalline polypropylene, using an insoluble volatile liquid. The process involves the production of a substantially uniform dispersion of fine, discrete masses of blowing agent in a matrix of melted polymer, and extrusion and cooling of the dispersion without substantial coagulation of the fine masses. Methyl formate is included in a list of possible volatile liquids that can be used in this process. Further, Overcashier discloses the use of a single, insoluble liquid and does not disclose or suggest the use of liquid blends.
U.S. Pat. No. 3,976,605 to Matsunaga et al., which is incorporated in its entirety herein by reference thereto, is directed to a foamed plastic of a resin composition including a pullulan type resin and thermoplastic resin. The pullulan resin is a high-molecular weight linear polymeric glucose, having a molecular weight of 10,000 to 5,000,000. The pullulan resin includes both an etherified pullalan and an esterified pullalan. Methyl formate is included in a list of possible volatile liquid foaming agents suitable for use in this process, particularly as an example of a suitable low boiling ester.
U.S. Pat. No. 3,281,259 to Lux et al., which is incorporated in its entirety herein by reference thereto, is directed to a process for rendering the surface of a polyethylene foam sheet printable or receptive to coating by another polymer by creating open cells in the surface of the solid or foamed polyolefin. The process can include i) heating the surface of the foam sheet to produce a surface permeated by a large number of very fine pores; ii) chilling the surface of a foamed polyolefin to produce an unfoamed polyethylene "skin", which is then rapidly heated to a high enough temperature to create open cells in the surface layer only; or iii) passing a conventional closed cell foamed polyolefin sheet under a microprecision surface grinder so that only the surface layer of polymer is ground away leaving exposed open fragments of bubbles on the surface of the skin. Methyl formate is included in a list of possible volatile liquid foaming agents that can be used in this process.
U.S. Pat. No. 5,026,736 to Pontiff et al., which is incorporated in its entirety herein by reference thereto, is directed to moldable shrunken foam beads. The beads are produced by extruding a mixture of a thermoplastic foamable polymer and a blowing agent, cutting the melt to form foam beads, allowing the beads to shrink to a predetermined density, and, optionally, treating the beads to crosslink the thermoplastic polymer foam by chemical means or electromagnetic radiation. Through proper choice of blowing agents and gas permeation modifiers, the foam beads typically shrink within about 15 minutes after extrusion and cutting. The "shrunken" beads are thus defined as being reduced from their maximum expansion to produce surface wrinkles, dimples or the like. The shrinkage occurs because of the blowing agent's rapid diffusion from the foam structure relative to its replacement with air and/or the low room temperature vapor pressure of the blowing agent, which causes a decrease in the volume of the cells as cooling progresses. Methyl formate is included in a list of possible volatile organic blowing agents that can be used in this process.
U.S. Pat. No. 5,059,376 to Pontiff et al., which is incorporated in its entirety herein by reference thereto, is directed to a process for accelerated removal of residual blowing agents from objects produced from foamed thermoplastic polymers. The process involves subjecting the extruded foam to an elevated temperature to remove a substantial portion of the residual blowing agent and to cause sufficient air to diffuse into the foam so as not to cause substantial collapse of the foam. The foam sheets used in the process described in Pontiff are generally 0.25 inch thick or less. Methyl formate is included in a list of possible volatile organic blowing agents that can be used to produce the polyolefin foams used in the process. The amount of residual blowing agent remaining in the foam after the process will vary with the various blowing agents used, but generally will be less than two weight percent of the foam product.
U.S. Pat. No. 5,391,335 to Sakamoto et al., which is incorporated in its entirety herein by reference thereto, is directed to a process for producing an insulated electric wire having an insulated layer made of a polyolefin foam. The foaming agent is a mixture of at least two compounds, one compound including the group consisting of ethers, esters, ketones and saturated hydrocarbons having boiling points of 100° C. or below and at least one additional liquid compound selected from the group consisting of ethers, esters, ketones, saturated hydrocarbons and alcohols having boiling points higher than 100° C. but not exceeding 150° C. The molten mixture, consisting of resin, blowing agents and additives, is extruded from the die into a cross-head portion which has a conductor-wire continuously guided therein. This allows the molten mixture to coat the periphery of the conductor and foam into a foam-insulating layer.
U.S. Pat. No. 5,565,497 to Godbey et al., which is incorporated in its entirety herein by reference thereto, is directed to a process for the manufacture of a closed cell, rigid, polymer foam which contains a well-dispersed filler. A non-ionic fluorochemical surfactant is used in the formulation to help disperse the filler in order to improve the insulation value of the foam. The filler material may include a variety of inert, non-reactive substances, including particulate clays, carbons, metals, minerals, polymeric materials and diverse chemical compounds and mixtures thereof. Methyl formate is included in a list of possible volatile organic blowing agents that can be used to produce the polyolefin foams used in the this process.
Therefore, a need exists for blowing agents employing methyl formate and environmentally friendly co-blowing agents, preferably non-VOC co-blowing agents, as components of the blowing agent blend to produce stable polyolefin foams, without compromising the product quality in terms of appearance, mechanical or compressive strength, and that enable a cost-effective and versatile manufacturing process.

Expanded and extruded polyolefin foams made with methyl formate-based blowing agents


Polyhydroxyl and polyether hydroxyl esters of fatty acids and polyether hydroxides are provided as waterproofers. These waterproofers are also combined with quaternary ammonium compositions and a solvent in waterproofing, wood preservative systems. Preferred quaternary ammonium compounds have chloride, hydroxide, carbonate, carboxylate, or borate counter ions.

Quaternary ammonium compounds (quats) and particularly didecyldimethylammonium chloride (DDAC) ##STR1## are commonly used as wood preservatives because they possess resistance properties to fungi and termites, to loss of strength, and to electrical sensitivity similar to those of commonly used acidic copper/chromium/arsenic solution (CCA) or ammoniacal copper and arsenic salt solution preservatives. See Proc of the Am. Wood Pres. Assoc., 80: 191-210 (1984). Although chloride quats do not include potentially dangerous heavy metals, didecyldimethylammonium chloride leaches rapidly in soil (Nicholas et al., Forest Prod. J., 41: 41 (1991), and therefore, does require coupling with copper salt.
Findlay et al., U.S. Pat. No. 4,929,454, disclose a method of preserving wood by impregnation with a quaternary ammonium compound and at least one of zinc and copper, wherein the quat anion is chosen from the group consisting of hydroxide, chloride, bromide, nitrate, bisulfate, acetate, bicarbonate, and carbonate, formate, borate and fatty acids. These quats have distinct environmental and safety advantages over commonly used acidic copper/chromium/arsenic solution (CCA) or ammoniacal copper and arsenic salt solution preservatives in that potentially dangerous heavy metals are not included. The Findlay et al. quats require copper or zinc in order to render them relatively insoluble and to prevent them from leaching out of a treated substrate. The use of copper or zinc in the above formulations may yet raise environmental and corrosion concerns.
Additionally, didecyldimethylammonium chloride tends to absorb preferentially to the surface of the wood and does not uniformly treat the whole substrate. Finally, DDAC treated wood shows surface erosion or ages upon exposure to light. See Preston et al., Proc. Am. Wood Pres. Assoc., 83: 331 (1987).
The biocidal activities of various chloride quats against bacteria, fungi, and algae are tabulated in Cationic Surfactants, E. Jungerman Ed., pp. 56-57, Marcel Dekker, Inc., 1969. Nicholas, "Interaction of Preservatives with Wood," Chemistry of Solid Wood, Advance in Chemistry Series #207, Powell ed., (A.C.S. 1984) notes that didecyldimethyl ammonium compounds and particularly DDAC are potential biocides. Preston, J.A.O.C.S. 60: 567 (1983) concurs and suggests that maximum fungitoxicity is exhibited with dialkyldimethyl compounds having C.sub.10 -C.sub.12 alkyl groups. Butcher et al., Chem Abstracts No. 91: 152627b, suggests that the presence of an acid or a base can affect the activity of didecyldimethyl-ammonium quats.
Didecyldimethylammonium acetate was used as a phase transfer catalyst for an oxidation in Chem Abstracts No. 97: 9175. A wood preservative was prepared by autoclaving didecylmethylamine with gluconic acid and ethylene oxide in isopropanol to yield (C.sub.10 H.sub.21).sub.2 CH.sub.3 N ((CH.sub.2).sub.2 O).sup.+ gluconate in Chem Abstracts No. 109: 124403x, while disinfectant solutions were prepared by exchanging a benzylammonium chloride with a chlorhexidene gluconate in Chem Abstracts No. 103: 109954f.
Biocidal compositions which include quaternary ammonium compounds of the formula R.sup.1 N.sup.+ R.sup.2 R.sup.3 R.sup.4 X.sup.-, wherein at least one of R.sup.1, R.sup.2, or R.sup.3 is a C.sub.8 -C.sub.30 alkyl or alkenyl group and the remainder of R.sup.1, R.sup.2 or R.sup.3 is methyl, ethyl, CH.sub.2 Ph or 4-pyridylmethyl; R.sup.4 is methyl or ethyl; and X is an anion of an acid having a C.sub.7 or greater hydrophobic group, were disclosed in Chem Abstracts Nos. 113:154360f and 113:153776j. Chem Abstracts No. 112:79768u discloses compounds of the formula R.sup.1 R.sup.2 R.sup.3 R.sup.4 N.sup.+ X.sup.-, wherein R.sup.1, R.sup.2, and R.sup.3 are methyl, ethyl, benzoyl, 4-pyridinomethyl and at least one is C.sub.8 -C.sub.30 alkyl or alkenyl; R.sup.4 is methyl or ethyl; and X is a counter anion of acids having C.sub.7 or greater hydrophobic groups. Dimethyldidecylammonium dodecylbenzenesulfonate was demonstrated to impart long term rot resistance to wood without causing rust, while the chloride salts of similar compounds were demonstrated to cause rust.
Patton et al., U.S. Pat. No. 5,004,760, disclose polymeric foams incorporating various dialkyldimethylammonium carboxylates such as didecyldimethylammonium poly(ethylene/acetate) and the like.
Quaternary ammonium compounds (quats) are typically prepared by the reaction: EQU R.sup.1 R.sup.2 R.sup.3 N+R.sup.4 X.fwdarw.R.sup.1 R.sup.2 R.sup.3 R.sup.4 NX (II)
wherein X is a halogen, a sulfate, a sulfo compound, or the like. When at least one of R.sup.1, R.sup.2, R.sup.3, or R.sup.4 is C.sub.12 or longer, the product is an inert soap. Many of the inert soaps have biocidal activity against bacteria, fungi, algae, and related organisms.
Reaction (II) above is limited by the reactant R.sup.4 X because R.sup.4 must react with tertiary amines. For example, methyl chloride (R.sup.4 X=CH.sub.3 Cl) will react with a tertiary amine at less than 100.degree. C. to yield a quaternary compound R.sub.3 N.sup.+ CH.sub.3 Cl.sup.-, while methanol or methyl acetate (R.sup.4 X=CH.sub.3 OH or CH.sub.3 COOCH.sub.3) will not, under similar reaction conditions.
General quaternary ammonium compounds with a sulfo group are easily prepared either by the reaction of a sulfate compound with a tertiary amine (III) or by a double exchange (IV). EQU R.sub.3 N+RSO.sub.3 CH.sub.3 .fwdarw.R.sub.3 NCH.sub.3.sup.+ RSO.sub.3.sup.-(III) EQU R.sub.3 N.sup.+ CH.sub.3 Cl.sup.- +RSO.sub.3.sup.- Na.sup.+ .fwdarw.R.sub.3 NCH.sub.3.sup.+ RSO.sub.3.sup.- +NaCl (IV)
If trimethylamine is heated with carbon dioxide and methanol above 200.degree. C. and at 85 to 95 atmospheres, the carbonate quat, bis-tetramethylammonium carbonate, is prepared. Industrial Organic Nitrogen Compounds, Astle Ed. p 66, Reinhold Inc, 1961. However, this reaction is limited to the methyl compound because higher homologs decompose to olefins by the Hofman elimination reaction. See, Organic Reactions, 11, Chptr. 5, 377, Krieger Publishing Co., 1975.
Chem Abst. 110: 212114 (1989) suggests that dimethyl carbonate will react with triethylamine in methanol in twelve hours at 115.degree. C. and under pressure to yield a methyl carbonate ester quat.
Chem Abst. 114: 24824 (1991) discloses that 6-hydroxy- or hexyl-dimethylamine reacts with dimethyl carbonate to yield a carbonate ester quat.
Quaternary ammonium hydroxides (hydroxy quats), an intermediate in the reaction scheme of the present invention, are currently prepared by the reaction of quaternary ammonium iodide with silver oxide (V). EQU RN.sup.+ (CH.sub.3).sub.3 I.sup.- +AgO.fwdarw.RN.sup.+ (CH.sub.3).sub.3 OH.sup.- +AgI (V)
However, this reaction is costly, and it is difficult to recover the silver reagent. See, Organic Reactions, 11: Chptr 5, pp. 376-377, Krieger Publishing Co., 1975.
In an olefin synthesis, it has been suggested to treat a quaternary salt with aqueous sodium or potassium followed by pyrolysis in order to form the hydroxy quat and then to decompose the hydroxy quat directly. However, in this method the hydroxy quat is not isolated and the conditions for its preparation are undesirable. See, Organic Reactions, 11: Chptr 5, pp. 376-377, Krieger Publishing Co., 1975.
Talmon et al., Science, 221, 1047 (1983), have used an ion exchange resin to convert didecyldimethylammonium bromide to didecyldimethylammonium hydroxide (VI). EQU (C.sub.12 H.sub.25).sub.2 (CH.sub.3).sub.2 N.sup.+ Br.sup.- +Ion Exchange Resin.fwdarw.(C.sub.12 H.sub.25).sub.2 (CH.sub.3).sub.2 N.sup.+ OH.sup.-(VI)
However, 50 ml of ion exchange resin and two treatment steps were required to convert 3 grams of quaternary ammonium chloride to the corresponding hydroxide. Talmon et al. state that the hydroxy quat can be reacted with acids to make quats with different anions, and they have prepared didodecyldimethylammonium (DDDA) acetate, DDDA-formate, DDDA-propionate, DDDA-butyrate, DDDA-oxalate, DDDA-acrylate, DDDA-tartrate, DDDA-benzoate, and DDDA-octanoate. See also, Organic Synthesis, Collective Volume VI, 552, John Wiley Inc., 1988; Brady et al., J. Am. Chem. Soc., 106: 4280-4282, 1984; Brady et al., J. Phys. Chem., 90: 9, 1853-1859, 1986; Miller et al., J. Phys. Chem, 91: 1, 323-325, 1989; Radlinske et al., Colloids and Surfaces, 46: 213-230, 1990.
Distearyldimethylammonium gluconate was prepared via ion exchange and subsequent reaction with an organic acid in Chem Abstracts No. 75: 119170U. Miller et al, Langmuir, 4: 1363 (1988) prepared ditetradecyldimethylammonium acetate by ion exchange from a bromide.
Alternatively, quaternary ammonium hydroxide compositions have been prepared by treating a haloquat in an electro-chemical cell with special cation exchange diaphragms between the cells. The hydroxy quat collects at one electrode, and the halide collects at the other. Hydroxy quats, R.sup.1 R.sup.2 R.sup.3 R.sup.4 N.sup.+ OH.sup.-, wherein the R groups were C.sub.1 -C.sub.4, were treated with carboxylic acids to make asymmetric quats that were used as capacitor driving electrolytes. See, Japanese Patent Publication No. 02-106,915 and Awata et al., Chemistry. Letters, 371 (1985). Awata et al. placed carboxylic acids in the cathode cell to react with tetraethylammonium hydroxide as it was formed.
Japanese Patent Publication No. 01-272-363 discloses the preparation of relatively low yields of tetraethylammonium hydroxide by reacting triethylamine with diethyl sulfate, heating the resultant quat with sulfuric acid to yield the sulfate quat, and reacting the sulfate quat with barium hydroxide to yield the short chain quat, tetraethylammonium hydroxide, and barium sulfate.
Di C.sub.8 -C.sub.12 alkyl quaternary ammonium hydroxides prepared by ion exchange were used as strong bases to digest animal tissue by Bush et al., French Patent Publication No. 1,518,427.
Akzo discloses that the addition of a metallic hydroxide to a quaternary ammonium chloride such as didecyldimethylammonium chloride, in an aqueous medium, results in an equilibrium mixture of quaternary ammonium chloride and quaternary ammonium hydroxide (VI). This reaction can be driven to the right by the use of isopropanol as a solvent. EQU (R.sub.4 N)Cl+KOH.apprch.(R.sub.4 N)OH+KCl (VII)
Akzo further discloses that the addition of a soap to a quaternary ammonium chloride yields a quaternary ammonium carboxylate (VII). EQU (R.sub.4 N)Cl+R.sup.1 COONa.fwdarw.(R.sub.4 N) (OOCR.sup.1)+NaCl (VIIA)
Jordan et al., U.S. Pat. No. 3,281,458, disclose the preparation of dioctadecyldimethylammonium humate, ditallowdimethylammonium humate, dipentadecyldimethylammonium humate, and didodecyldimethylammonium humate by reacting humic acid, lignite, aqueous sodium hydroxide and a chloride quat.
Finally, Nakama et al., J.A.C.O.S., 67: 717 (1990) report the interaction between anionic and cationic surfactant and particularly sodium laureate and stearyltrimethylammonium chloride, while Linderborg, U.S. Pat. No. 4,585,795, disclose the use of synergistic mixtures of the alkali metal salt of certain biocidal organic acids, quaternary ammonium chlorides, and alkyl-pyridinium chlorides as control agents for short-term protection of timber against sapstain fungi and mildew.
Typically, quaternary ammonium compounds migrate or leach from wood under wet conditions, however. Common waterproofing compositions have not proven compatible with the quaternary ammonium compounds typically used in the industry, and therefore, they are not commonly used to hinder the leaching of these quats.
Typical waterproofers are waxes, lower molecular weight polyolefins, or dispersions or solutions thereof in hydrocarbon solvents. However, quaternary compositions, including those useful in the present invention, typically are water soluble. Generally, they are not soluble in these typical waterproofer solvent systems and are not compatible with emulsified or dispersed waterproofers.
It has now been discovered that C.sub.1 -C.sub.20 alkyl or aryl-substituted alkyl, C.sub.8 -C.sub.20 alkyl, and particularly di C.sub.8 -C.sub.12 alkyl, quaternary ammonium hydroxides, carbonates, carboxylates, and borates including those prepared by the methods described herein, are compatible with newly discovered polyhydroxyl or polyetherhydroxyl esters of fatty acids or polyether hydroxide waterproofers. Waterproofing and wood preservative systems prepared from the waterproofers or waterproofers and quats described herein exhibit enhanced resistance to leaching and meet waterproofing standards for heavy duty, ground, or millwork applications.

Waterproofing and preservative compositions and preparation thereof


Disclosed is a device, system and methods for tracking conductive composite pressurized gaseous storage tanks. The system including anchoring an RFID device in a non-conductive blind boss. Wherein the anchor material has a low dielectric and has minimal reflection if RF energy.

1. Field
This disclosure relates to a blind boss mounting for an insulated RFID tag connection tank.
2. General Background
There is an ongoing balance between safety and weight with respect to pressurized fuel in motor vehicles traditional methods of reducing tank weight have included using plastic lined tanks wrapped in fibers within a binding matrix and having a fluid connection for fill/unfill FIG. 1 shows a traditional composite tank structure. Such composite pressure vessels "T" is constructed by wrapping reinforcing fibers in a binding matrix forming a wrapped region "W" over a plastic liner "L". A polar boss "O" is connected to the liner and is partially in the wrappings. The boss has a fluid-connection "V" to the inside pressure chamber "I.V.". Fiber materials are often formed of carbon fibers or other conductive materials.
These composite tanks weight less than metal tanks but are more susceptible to damage from cuts, gashes and the like. Tanks are also susceptible to stress related to weather, fill and unfill sequence. Such tanks should be inspected upon regular intervals. Such tanks are also expensive and susceptible to theft. Finally, such tanks have projected and actual life cycles depending on use, damage and the like.

Composite pressure tank identification and tracking


A user equipment (UE) transmits a first START value to a serving radio network controller (RNC), and utilizes the first START value as a most-recently transmitted START value. A serving radio network subsystem (SRNS) relocation procedure is then initiated between the UE, the serving RNC and a target RNC. In response to the SRNS relocation procedure, the serving RNC transmits a SRNS relocation information container to the target RNC. The SRNS relocation information container includes the START value of each CN domain and the Latest configured core network (CN) domain. The target RNC utilizes the START value of the Latest configured CN domain to initialize the hyper-frame numbers (HFNs) of radio bearer RB2. The UE re-establishes RB2 and utilizes the first START value to initialize the HFNs of RB2. The UE then transmits a response message to the target RNC on RB2.

1. Field of the Invention
The present invention relates to a wireless communications system. More particularly, the present invention relates to synchronizing hyper-frame numbers during a SRNS relocation procedure in a 3GPP wireless system.
2. Description of the Prior Art
As explained in the 3rd Generation Partnership Project (3GPP) specifications 3GPP TS 25.322 V3.10.0 "RLC Protocol Specification", and 3GPP TS 25.331 V3.10.0 "Radio Resource Control (RRC) Specification", which are included herein by reference, serving radio network subsystem (SRNS) relocation is performed to transfer user equipment (UE) from one radio network controller (RNC) to another RNC. Various reconfiguration procedures may involve SRNS relocation, which is indicated by certain information elements (IEs) included in the reconfiguration message.
When receiving a reconfiguration message indicating that SRNS relocation is to occur, the UE re-establishes the radio link control (RLC) entity of radio bearer RB2, and re-initializes the uplink and downlink hyper frame number (HFN) components of the COUNT-Cs for RB2 with MAX(uplink HFN of RB2, downlink HFN of RB2)+1, where MAX(a, b) gives the larger of a and b. The UE also calculates the START value for each core network (CN) domain according to subclause 8.5.9 of the RRC specification TS 25.331 V3.10.0, and includes these START values in the IE "START list" in the response message.
The UE then transmits the response message to the UTRAN on RB2, thereby providing the UTRAN with most recently transmitted START values. After the RLC has confirmed the successful transmission of the response message, the UE re-establishes the RLC entities of other radio bearers and re-initializes the HFN of the COUNT-C values for each radio bearer with the START value included in the response message for the corresponding CN domain.
As described in the prior art, in the event that SRNS relocation is involved in a reconfiguration procedure, the UE shall re-establish the RLC entities of RB2 and re-initialize the HFN of the COUNT-C for the radio bearer before transmitting the response message.
For the Target RNC to be able to decipher the response message sent by the UE on RB2, the UL COUNT-C of the UE and the UTRAN have to be initialised with the same value, i.e. MAX (uplink HFN component of COUNT-C of RB2, downlink HFN component of COUNT-C of RB2)+1. The UL HFN and DL HFN of RB2 are provided to the Target RNC by the Source RNC in an SRNS Relocation Info container. The data in the SRNS Relocation Info container is forwarded via the CN. There is a possibility that between the time at which the Source RNC evaluates the HFN and the instant when the UE does so, some RRC messages may be sent on the UL of RB2 (for example, Measurement Report messages). If the UL HFN of RB2 is greater than the DL HFN of RB2, and if the RLC sequence numbers on the UL of RB2 are close to roll over, such messages may trigger an HFN increment in the UE but not in the UTRAN, as those messages might not have been considered when the UL HFN is sent from the Source RNC to the Target RNC. Under such circumstances, the COUNT-C of RB2 will not be initialised with the same value in the two entities (i.e., the UE RLC entity and the Target RNC RLC entity). If this happens, the Target RNC will be unable to correctly decipher the response message, and the SRNS relocation procedure will consequently fail.
The SRNS relocation may also be initiated by a cell update procedure, and in which case the above-noted problem continues to exist.

Correction to HFN initialization for RB2 during SRNS relocation


A calibration circuit for calibrating harmonics in a mixer. The calibration circuit includes an RF signal path configured to receive an RF signal corresponding to an output of the mixer, selectively receive a test signal injected into the RF signal path, and provide feedback to the mixer according to the RF signal and/or the test signal. The test signal corresponds to a selected harmonic of the harmonics in the mixer. A measurement circuit is configured to detect, in the output of the mixer, the test signal injected into the RF signal path. A calibration module is configured to receive a feedback signal indicative of the test signal detected in the output of the mixer and, based on the feedback signal indicative of the test signal detected in the output of the mixer, adjust a duty cycle associated with the mixer to calibrate the selected harmonic.

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Radio frequency (RF) receivers typically rely on hard-switched mixers to perform down conversion. Down conversion refers to translation of an incoming modulated signal from a higher frequency to a lower frequency. Up conversion from a lower frequency to a higher frequency is also performed when transmitting the signal.
FIG. 1 shows an example of a portion of an RF receiver 10 to perform down conversion. The RF receiver 10 includes an antenna 19 that is coupled to an optional RF filter 20 and a low noise amplifier 22. An output of the amplifier 22 is coupled to a first input of a mixer 24. A second input of the mixer 24 is connected to a local oscillator (LO) 25, which provides a reference frequency. The mixer 24 converts radio frequency (RF) signals to intermediate frequency (IF) signals. An output of the mixer 24 is connected to an optional IF filter 26. The RF receiver 10 may include additional circuits to perform additional down conversion and processing.
FIG. 1B shows an example of a portion of an RF transmitter 50 to perform up conversion. The transmitter 50 includes a variable gain amplifier (VGA) 84 that receives IF signals and that is coupled to an optional IF filter 85. The optional IF filter 85 is connected to a first input of an IF to RF mixer 86. A second input of the mixer 86 is connected to an oscillator 87, which provides a reference frequency. An output of the mixer 86 is coupled to an optional RF filter 88. The optional RF filter 88 is connected to a power amplifier 89, which may include a driver. The power amplifier 89 drives an antenna 90 through an optional RF filter 91.
When a frequency range of the incoming modulated signal of the RF receiver has an upper-bound larger than twice a lower bound, harmonic mixing can be an issue. Unwanted signals lying on harmonic frequencies of the local oscillator are down converted and interfere with the wanted signal, which lies on a fundamental frequency of the local oscillator.
Harmonic rejection mixers attempt to reduce odd harmonic mixing. Intrinsic device matching is typically exploited to reject even harmonics. However, these approaches are not always sufficient to reduce even and odd harmonics, which adversely impacts silicon yield.
As used herein, η refers to duty cycle and ηnom refers to 50% duty cycle. DCoffset refers to DC offset with respect to a predetermined threshold voltage or current value (such as zero).
Balanced η refers to duty cycle equal to 50% (or ½) and unbalanced η refers to duty cycle not equal to 50% (or ½). IMnrefers to nth order inter-modulation. As IMn decreases, linearity increases. IIPnrefers to nth order input referred intercept point. IIP is proportional to 1/IMn. Therefore, linearity increases as IIPn increases.
FIG. 2 illustrates a duty cycle of a square wave signal. The pulse width τplus represents a period that the square wave signal is positive while the pulse period T represents a period of the local oscillator square wave. T is related to the fundamental frequency fLO of the LO as fLO =1/T.
Duty cycle is typically defined as the ratio of the pulse width to the period T and it is quantified as a percentage. For example, if the pulse width to period ratio is ½, then the effective duty cycle is 50%. Under these conditions, the square wave LO spectrum includes only odd harmonics of the fundamental frequency as can be seen in FIG. 3. Moreover, these harmonics have energy than decreases with increasing frequency. When the effective duty cycle is not equal to 50%, the LO spectrum also includes even harmonics as can be seen in FIG. 4.
FIGS. 5-7 illustrate a hard-switching mixer performing down-conversion in a receiver. Incoming RF signal energy at fLO±fIF is converted to a lower frequency fIF. The operation produced by the hard-switched mixer can be viewed as a multiplication, in the time domain, between the incoming RF signal and the sign of the local oscillator waveform. The time domain multiplication with the sign(LO) is what differentiates hard-switched mixers from analog multipliers where the RF incoming signal is multiplied with the LO waveform.
Because of the periodic and bipolar nature of the LO waveform, sign(LO) is a square-wave with the same period as the original LO waveform. Consequently, if the effective duty cycle of sign(LO) is 50%, the spectrum includes the odd harmonics. If the incoming RF signal includes only energy around the fundamental frequency of the LO (fLO), the rich harmonic content of sign(LO) is not an issue since only the useful/wanted energy will be translated around fIF and processed. However if the incoming RF signal has energy around the harmonics of the LO, hard-switched operation may create issues.
Referring now to FIGS. 8-9, when the incoming RF signal energy spreads close to any of the LO harmonics with some interferers, the nature of the hard-switched mixer downconverts the interferer to IF as well. Harmonic mixing distortion occurs when the interferer energy folds over the useful signal, which corrupts the information in the useful signal. Harmonic mixing distortion is an issue in wireless systems that handle RF bands (incoming for the RX and outgoing for the TX) where the upper bound is 2 or more times the lower bound.
When the LO is balanced (or equivalently has a duty cycle of 50%), harmonic distortion should be considered for odd LO harmonics. However, when the LO has a duty cycle that is different than 50%, even order harmonics appear in the sign(LO) spectrum. RF interferers located close to the even LO harmonics fold over the useful signal. Dotted lines in FIG. 9 illustrates the case where the LO has a duty cycle different than 50%, which leads to the down conversion at fIF of the interferer placed at fIF+2fLO.

This patent is subject to a terminal disclaimer.

Calibration circuit and methods for calibrating harmonics in a mixer


A clutch apparatus for releasing the transmission of rotation from an electric motor to a spin shaft, is equipped with a rear clutch nut and a front clutch nut in order from the rear end side. The rear clutch nut transmits rotating force from the electric motor to the front clutch nut when engaged with the front clutch nut, but is disengaged from the front clutch nut by a predetermined rotation load. The front clutch nut has a cylindrical shape, so that the spin shaft can be arranged at an axial center portion, and when engaged with the engaging unit of the spin shaft, the rotating force is transmitted to the spin shaft, but the clutch is disengaged by a backward stroke of the front clutch nut and a predetermined stroke toward the tip of the spin shaft.

An apparatus for fastening a blind nut to a member to be mounted (a blind nut tool) is required to perform two operations: rotation of a mandrel (mounting of a blind nut to a mandrel) and stroke (fastening of a blind nut).
In the case of the current pneumatic type blind nut tool, mounting is performed by an air motor, and fastening is performed by a hydraulic cylinder; however, in the case of an electric cordless blind nut tool, it is difficult to mount two motors—one for mounting and one for fastening—on the tool due to concerns about increased size and weight. In the case of a conventional tool with a POP electric cord, the mounting operation and the fastening operation are performed by one trigger operation; therefore, blind nut mounting and fastening cannot be operated individually, and fastening starts immediately after mounting is completed, so that it is necessary either to insert the blind nut into the work in advance or turn the blind nut by hand to mount it on the tool.
As described in Patent Document 1, while a tool exists that can individually operate mounting and fastening with one motor, the workability thereof is not satisfactory because two trigger operations are required for the mounting operation and the fastening operation.
Additionally, in Patent Document 2, while the blind nut can be mounted by pressing a mandrel, another motor is required for mounting. Further, cordless tools on the market are only able to use either fastening stroke management or fastening load management for fastening management. In Patent Document 3, measurement and the like can be performed together with the fastening force and stroke, but fastening control is performed only by the load.
Further, these existing tools require a position confirmation sensor for confirming the positions of the forward end and the backward end of the tool, and if the sensor fails, the tool may be damaged.


Distributed communication traffic control systems and methods are disclosed. An amount of communication traffic received from a traffic management device and stored in a communication traffic queue at a communication device is monitored. Based on the amount of communication traffic stored in the communication traffic queue, a determination is made, at the communication device, as to whether a traffic management action is to be performed. If a traffic management action is to be performed, the traffic management device is controlled to perform the determined traffic management action. The traffic management device may receive an indication of the determined traffic management action from a distributed traffic controller in the communication device, for example, and perform the traffic management action responsive to the indication.

Currently available traffic management schemes typically have a centralized egress queuing point from which traffic is scheduled. This architecture results in a several fundamental problems relating to cost, flexibility and performance.
In terms of cost, the scale of traffic management requirements must generally be determined ahead of time and sufficient memory and other resources must be provided in an initial deployment. A negative impact of this approach is the high "cost of entry" that can be associated with meeting demanding traffic management requirements.
Flexibility can also be lacking in conventional traffic management systems, in that traffic management systems tend to be designed to fit unique customer applications, to support a number of queuing entities, depth of memory, number of virtual output ports, etc.
As the number of unique customer applications grows, the ability to monitor and react quickly enough to traffic flow changes that are specific to a particular customer application while still ensuring Service Level Agreements (SLAs) or other service commitments can be immensely challenging. Traffic management systems that are on the market today might not adequately meet this performance challenge.
Especially for egress (customer facing traffic flow) in modern communication equipment such as routers and switches, the number of interfaces and/or the number of uniquely identifiable customer traffic flows can be much greater than the physical number of "entities" that existing traffic management systems can differentiate and react to. Although software-based backpressure mechanisms have been developed to address this problem, such mechanisms might not be fast enough to sustain reasonably high customer data rates. For example, the effectiveness of many software backpressure mechanisms degrades at DS3 rates and above.
Thus, there remains a need for improved communication traffic control techniques.


A pressure transmitter for measuring a pressure of a process fluid includes a pressure sensor, a hydraulic relay system and a pressure sensor fill fluid. The pressure sensor senses the pressure of the process fluid, and the hydraulic relay system provides a communication channel between the process fluid and the pressure sensor. The pressure sensor fill fluid in the hydraulic relay system comprises a first hydraulic fluid and a first volume of nano-particles. The first hydraulic fluid transmits a change in the pressure of the process fluid to the sensor. The first volume of nano-particles is suspended within the first hydraulic fluid and alters properties of the pressure sensor fill fluid.

This invention relates generally to process instruments used in industrial process control systems. More particularly, the present invention relates to hydraulic fill fluids used in pressure transmitters.
Process transmitters are used to remotely monitor process variables of process fluids. For example, pressure transmitters are commonly used in the chemical processing industry for sensing pressures of petrochemicals or water. A pressure transmitter includes a sensor or transducer that produces an electrical output in response to physical changes in a process pressure. For example, a capacitive pressure transducer produces an electrical signal based on a change in capacitance due to a change in the pressure of a process fluid. The electrical signal of the sensor is processed by the transmitter circuitry to produce an electrical output that can be monitored as an indication of the pressure of the process fluid. Pressure transmitters also include electronics and circuitry for either remotely monitoring the electrical output through a control loop or network at a central monitoring location such as a control room, or locally such as with an LCD screen.
A typical capacitive pressure transducer includes a simple hydraulic system for communicating the process fluid pressure to the capacitive transducer. The hydraulic system is comprised of a hydraulic passageway that is filled with a precise level of fill fluid. At a first end of the hydraulic passageway is a transmitter isolation diaphragm that separates the fill fluid from the process fluid. At a second end of the hydraulic passageway is a sensor diaphragm that serves as a variable capacitor plate for the pressure sensor. The fill fluid typically comprises a hydraulic fluid that conveys the process fluid pressure from the transmitter isolation diaphragm to the sensor diaphragm. As the process fluid pressure fluctuates, the process fluid exerts a corresponding force on the isolation diaphragm at the first end of the hydraulic system, which through the fill fluid adjusts the position of the sensor diaphragm.
Additionally, remote seal systems are often used to distance the pressure transmitter from hazardous measurement environments, or for linking the pressure transmitter with inconveniently located process fluids. For example, remote seals are often used with corrosive or high temperature process fluids. In those situations, a remote seal having a capillary tube filled with hydraulic fill fluid can be used to relate the pressure transmitter to the process fluid while the pressure transmitter is located a safe distance away. The capillary tube may extend tens of meters in order to couple the pressure transmitter with the process fluid. The remote seal includes an isolation diaphragm at a first end of the capillary tube that separates the fill fluid from the process fluid. The second end of the capillary communicates with the isolation diaphragm of the transmitter. The incompressible fill fluid thus translates a pressure change of the process fluid from the remote seal isolation diaphragm to the transmitter isolation diaphragm. Thus, the electrical output of the pressure sensor is directly related to qualities of the hydraulic fill fluid, such as volume and capacitance, in the hydraulic system and the remote seal.
Process transmitter passageways and remote seal capillary tubes are filled at the factory with a precise amount of hydraulic fill fluid and then sealed. System performance is correlated with the precise level of fill fluid and is degraded with temperature fluctuations. For example, pressure transmitters are frequently used in high temperature settings. Fill fluids operating in such environments undergo thermal expansion that asserts forces against the various isolating diaphragms, which causes the pressure sensor to read a "back pressure," thus interfering with obtaining accurate pressure readings from the process fluid. Additionally, the capacitance of capacitive pressure sensors is affected by the presence of the hydraulic fill fluid between the capacitor plates of the sensor. Therefore, there is a need for hydraulic fill fluids having improved operating characteristics and qualities.

Nano-particle modified fill fluid for pressure transmitters