A process for forming solid cast detergent products comprising the steps of: (a) forming an aqueous detergent slurry comprising from about 60 to about 90 parts by weight of solid detergent ingredients, per 100 parts of total detergent slurry weight, said solid detergent ingredients comprising: (i) from about 5 to about 50 parts by weight of a surfactant; (ii) from about 0.1 to about 10 parts by weight of a salt-form builder component; (iii) from about 30 to about 75 parts by weight of a hydrated alkaline component; (b) adding from about 0.5 to about 10 parts by weight of a sugar surfactant selected from the group consisting of an alkyl polyglycoside, a glucamide, and mixtures thereof, to form a uniform dispersion; and (c) casting said uniform dispersion to form a solid cast detergent product.

In the manufacture of powdery or granular detergent compositions, it is common practice to prepare a relatively high solids aqueous crutcher slurry containing a surfactant ingredient, a builder ingredient and water. The crutcher slurry is then spray dried to form the desired powdery or granular detergent product.
When preparing a powdered or granular detergent in the foregoing fashion, there is a significant economic incentive to minimize the amount of water present in, and to maximize the dry solids content of, the crutcher slurry, thereby reducing the amount of energy required in drying the slurry to form the desired granular or powdered detergent product. Naturally, however, there are also practical upper limits within actual granular or powdered detergent manufacturing operations upon the maximum solids content which can be achieved while still providing a pumpable/sprayable slurry as well as upon the combinations of ingredients, suitable for preparing stable, homogeneous high solids aqueous crutcher slurries or suspensions.
While attempts at increasing the solids content of aqueous crutcher slurries used to form granular and powdered detergent products have shown to be successful, their use in today's institutional and industrial spray washing machines is not pragmatic for various reasons. In the past, conventional institutional and industrial spray washing machines employed liquid or powdered detergents which were generally added to the wash tank by means of an automatic dispenser system. All forms of such detergents, whether liquid or solid, have stability problems and other problems associated with their manufacture, dispensing or use. Moreover, in the early days of the development of solid detergents, when these detergent products were relatively low in performance compared to the products of today, the problems were less severe. However, the advent of high performance products stimulated in part by increased aesthetic and sanitary standards and a demand for shorter wash times has generally been characterized by the development of more complex detergent compositions which are more hazardous to the user, less stable, and more difficult to dissolve in a satisfactory uniform manner.
For example, higher performance solid detergents generally means higher alkalinity, i.e., greater concentrations of sodium hydroxide, higher to the point of posing safety hazards to the user. Historically, detergents used for warewashing have been relatively low in alkalinity. The extensive use of aluminum trays and utensils, the presence of soft metals in wash pump impellers and other factors generally prevented the use of high alkalinity detergents. Today, however, there has been a trend toward the use of high alkalinity, higher performance products. This trend has been partially the result of the increased usage of stainless steel and corrosion resistant plastics in the production of utensils. In addition, the aforementioned increased standards and shorter wash times required by the increased volume of business in eating establishments have created a demand for these higher performance products.
In an effort to minimize the contact between the user and the detergent composition, solid cast detergents have been introduced. These detergents originate in aqueous form and are subsequently cast (hardened) into a solid homogenous block of detergent. These detergent blocks are then inserted into warewashing machines and dispensed by spraying water over the block, thereby releasing a predetermined amount of the detergent for use in cleaning.
While cast detergent products by and large provide adequate cleaning and wash times, there still exists a need for more concentrated cast detergent products which provide greater cleansing power in even shorter time periods. One way to meet these demands is by increasing the solids content of the cast detergent product, thereby providing for a more concentrated product having increased levels of cleaning ingredients.
Moreover, by increasing the solids content of the aqueous detergent slurries used to make the solid cast product, less time and energy are required for the product to cast (harden). Hence, by increasing solids content, a more concentrated and cost-efficient product is formed.
The mere addition of more solid detergent ingredients to an aqueous slurry, however, is not the solution since an increase in solid ingredients alone such as anionic surfactants causes the aqueous slurry to become too viscous to handle, thereby precluding the formation of an acceptable homogeneous solid cast detergent product.
It is therefore an object of the present invention to provide a process for producing solid cast detergent products having high solids content levels by reducing the initial viscosity of the aqueous slurry prior to casting, thereby controlling both the set-up time of the slurry and the final hardness of the solid cast detergent product.

Process for preparing solid cast detergent products


A synchronous acquisition device for a small-circuit-scale CDMA receiver is provided. The synchronous acquisition device for a CDMA receiver, which receives as a receiver signal a spectrum-spread signal generated by spectrum-spreading, using a spreading code, transmission data including one of first to mth pieces (m: an integer 2 or more) of fixed data, comprises, for each of a plurality of paths into which the receiver signal is branched, a multiplier (21) for multiplying the receiver signal by the spreading code, an integrator (12) for one-symbol-time integrating an output signal from the multiplier (21), fixed data sequential output units (251 to 25m, 24) having the first to mth pieces of fixed data and sequentially outputting the first to mth pieces of fixed data, and a second multiplier (23) for multiplying an output signal from the integrator (12) by the first to mth pieces of fixed data sequentially outputted from the fixed data sequential output units.

In the broadband CDMA (Code Division Multiple Access) system, which is expected to become a standard system for next-generation cellular phones, signals are spread over wide spectrum by using a spreading code, and thus enabling one frequency band to be shared by plural channels. In addition, there is another advantage of high secrecy. On the other hand, in the CDMA system, it is necessary to provide a receiver with a circuit for eliminating the spreading code differently from a conventional narrow-band modulation system, which enlarges the circuit size.
In a CDMA transmitter, transmission data D(t) are multiplied by a spreading code c(t) to be a spectrum-spread transmitter signal s(t), and thereby transmitted. The transmission data D(t) include a certain data sequence at the first part. The data are called fixed data and denoted by xi(t). The transmitter signal s(t) is sent through a transmission line and received by a CDMA receiver. The signal received at the CDMA receiver is denoted by r(t).
In the following, a description will be given of the case where data are transmitted by using one of plural pieces of fixed data x1(t), x2(t), x3(t), . . . , xm(t) as the above-mentioned fixed data xi(t) (m: an integer 2 or more; 1 (one)≦i≦=m). The CDMA receiver is previously provided with the values of the plural pieces of fixed data x1(t), x2(t), x3(t), . . . , xm(t), however, unable to decide which one of the pieces of fixed data x1(t), x2(t), x3(t), . . . , xm(t) are to be sent.
FIG. 9(A) illustrates a conventional synchronous acquisition device for a CDMA receiver. The synchronous acquisition device includes first to nth paths (n: an integer 2 or more), which are supplied with first to nth branch signals obtained by branching a receiver signal r(t), respectively.
The synchronous acquisition device further includes first to nth delay units 101, 102, 103, . . . , 10n connected to the first to nth paths. The first to nth delay units 101, 102, 103, . . . , 10n output first to nth delayed signals r1(t), r2(t), r3(t), . . . , rn(t), respectively, by giving different amounts of delays τ1, τ2, τ3, . . . , τn to each of the first to nth branch signals. That is, the jth branch signal that branches into the jth path of the first to nth paths (1 (one)≦j≦n) is delayed by the jth delay unit 10j and outputted as the jth delayed signal rj(t).
Subsequently, in the synchronous acquisition device, first to nth maximum correlation value generation units 151, 152, 153, . . . , 15n connected to the first to nth delay units 101, 102, 103, . . . , 10n generate first to nth maximum correlation values based on the first to nth delayed signals r1(t), r2(t), r3(t), . . . , rn(t).
Then, a synchronism-acquiring maximum value detector 14 connected to the first to nth maximum correlation value generation units 151, 152, 153, . . . , 15n detects a maximum value of the first to nth maximum correlation values to acquire synchronism.
FIG. 9(B) illustrates a detail of the nth maximum correlation value generation unit 15n of the first to nth maximum correlation value generation units 151, 152, 153, . . . , 15n in the synchronous acquisition device shown in FIG. 9(A). The other maximum correlation value generation units have the same structure as that of the nth maximum correlation value generation unit 15n.
As shown in FIG. 9(B), the nth maximum correlation value generation unit 15n branches a signal rn(t) delayed by the delay unit 10n into paths of the same number as m pieces of fixed data (namely, first to mth paths) as first to mth branch signals, and the first to mth branch signals are inputted to first to mth correlation devices, respectively. The first to mth correlation devices multiply the first to mth branch signals by the products of the first to mth pieces of fixed data x1(t), . . . , xm(t) and the spreading code c(t), respectively, and integrate first to mth multiplication results by an integrator′ 12 to output first to mth correlation values y1n(t), . . . , ymn(t). The first to mth correlation values y1n(t), . . . , ymn(t) outputted from the first to mth correlation devices get high when the first to mth branch signals are synchronized with the products of the first to mth pieces of fixed data x1(t), . . . , xm(t) and the spreading code c(t), when not, the values come low. A maximum value detector 14′ corresponding to the path of the nth maximum correlation value generation unit 15n detects a maximum value yin(t) max (1 (one)≦i≦m) of the first to mth correlation values y1n(t), . . . , ymn(t) as the nth maximum correlation value. In more detail, the maximum value detector 14′ corresponding to the path of the nth maximum correlation value generation unit 15n outputs the maximum correlation value yin(t) max and i corresponding to the maximum correlation value yin(t) max.
To sum up, in FIG. 9(A), the jth (1 (one)≦j≦n) maximum correlation value generation unit 15j of the first to nth maximum correlation value generation units 151, . . . , 15n outputs the jth maximum correlation value yij(t) max and i corresponding to the jth maximum correlation value yij(t) max. The synchronism-acquiring maximum value detector 14 in FIG. 9(A) detects a maximum value max {yij(t)max} of the maximum correlation values yij(t) max (1 (one)≦j≦n) to acquire synchronism, and outputs the detected maximum value max {yij(t)max}, and i and j corresponding to the maximum value max {yij(t)max}.
As is described above, inside the maximum correlation value generation units 151, 152, 153, . . . , 15n of FIG. 9(A), m integrators 12′ are lined up in parallel, which makes circuit size very big.
Incidentally, as shown in FIG. 9(B), each of the integrators 12′ includes an adder 16 for receiving an input signal at its first input terminal, and a delay element 17 composed of a latch L for delaying an output signal from the adder 16 by 1-symbol-time and outputting the delayed signal as an integrator output signal to input it to the second input terminal of the adder 16.
In the following, the operation of the synchronous acquisition device will be explained with reference to FIGS. 9(A) and 9(B).
Transmission data D(t) are expressed as follows:D(t)=xi(t) (0≦t<t0)D(t)=d(t) (t0≦t)  (1)In which d(t) denotes information data. That is, first (0≦t<t0), the transmission data includes fixed data xi(t) (1 (one)≦i<m), and subsequently (t0≦t), includes the information data d(t). The information data d(t) need to be synchronized with the fixed data xi(t) when received.
A transmitter signal s(t) is obtained by multiplying the transmission data D(t) by a spreading code c(t). Assuming that 0≦t<t0 with regard to time t, the transmitter signal s(t) is expressed as:s(t)=xi(t)c(t) (0≦t<t0)  (2).
An output yij(t) of the correlation device can be obtained by multiplying the receiver signal r(t)=s(t) by the spreading code c(t) and the fixed data xi(t) after giving a delay τj(1 (one)≦j≦n) in each path, and integrating the product by N-symbol-time as following expression. Then, a maximum value is detected among the paths to acquire synchronism.yij(t)=∫0t0r(t−τj)xi(t)c(t)dt  (3)

Synchronous acquisition device for CDMA receiver


An ink set includes an ozone stable cyan ink, and an ozone stable magenta ink. According to this exemplary embodiment, the ozone stable magenta ink includes an ozone stable magenta dye and a liquid vehicle including a fluorocarbon surfactant formed at least in part from a polymer comprising at least one Formula 1:

There are several reasons that ink-jet printing has become a popular way of recording images on various media surfaces, particularly paper. Some of these reasons include low printer noise, capability of high-speed recording, and capability of multi-color recording. Additionally, these advantages can be obtained at a relatively low price to consumers. Although there have been great improvements in ink-jet printing technology over the years, improvements can still be made in many areas.
As new ink-jet inks and print engines are developed, several traditional characteristics are considered when evaluating the ink in conjunction with a printing surface or substrate. Such characteristics include edge acuity and optical density of the image on the surface, gloss, black to color bleed control, dry time of the ink on the substrate, adhesion to the substrate, lack of deviation in ink droplet placement, presence of all dots, resistance of the ink after drying to water and other solvents, long term storage stability, and long term reliability without pen material degradation or nozzle clogging.
One characteristic of ink-jet printing systems that is desirable to achieve is related to optical density and bleed control. Additionally, achieving acceptable optical density and bleed control in ozone stable dyes is desired.

Abstract: Where R1=OH and R2=O(CH2)m-(CF2)nCF3 with m=1-3 and n=0-3.

Hewlett-Packard Development Company, L.P.


A method, system and computer program product for resolving values of parameters of tags. A map is created which includes the number of times each parameter is referenced by the tags in a web page requested by a client device. The parameters in the map are then sorted in a list in descending order based on the number of times referenced by the tags. The value for the parameter listed at the top of the list is looked up. If the value cannot be located, then those tags that are associated with this parameter are added to a list of tags to be ignored. By ignoring such tags in this list, the resolving of tag values for tags to be syndicated can occur more quickly and efficiently, including syndicating the tag data before the web page is completely loaded.

Current web pages utilize a variety of HTML tags from vendors for purposes of ad serving and tracking user behavior. A "tag" is a snippet of code that collects data, targets your ad campaign, tracks ads and performs other functions. An example of an HTML tag is the iFrame container which is used by many ad servers to place ads within web pages. Many other tags exist and each has a specific purpose (e.g., digital marketing, display remarking, web page analysis). A vendor may support various different "tag types," such as the page view tag, product view tag, order tag, etc. Each tag may be associated with one or more parameters, whose values are needed to be resolved at runtime (when the web page is loading) prior to syndicating (i.e., making available) the tag data, such as to the vendor's server. These values may be obtained from various elements (e.g., DOM elements, JavaScript elements, URL parameters, cookies) on the web page.
While HTML tags are necessary for many of today's websites, especially e-commerce sites, the main disadvantage of such tags is the requirement that all of the values of the tag parameters be resolved (obtained and validated) prior to syndicating the tag data, such as to the vendor's server. Some of these parameter values may not be immediately available, and as a result, such values may be looked up repeatedly in an attempt to resolve the parameter values thereby slowing page load times. Furthermore, the value of parameters, such as the parameters of JavaScript tags, may be obtained using the eval( ) function to obtain the value of the parameters. If there are a lot of parameters to be resolved, then there may be many eval( ) function calls leading to slower page load loads. Such slow page load times frustrate end users and lead to higher web page abandonment rates and thus potentially lower revenue for web page publishers.
As a result, there is not currently a means for efficiently resolving the values for the tag parameters thereby syndicating the tag data as early as possible even before the web page is completely loaded.

This patent is subject to a terminal disclaimer.

Efficiently resolving the values for the tag parameters thereby syndicating the tag data as early as possible

International Business Machines Corporation


It is aimed to provide a connector capable of ensuring the integrity of a lock arm and a detector in the process of deflecting the lock arm and enhancing a degree of freedom in designing the lock arm. A detector (60) movable in a front-back direction between a standby position and a detection position is assembled with a housing (10). The detector (60) includes a contact portion (78) displaceable together with a front end part (27) of a lock arm (23) during the interference of the front end part (27) of the lock arm (23) and a mating lock (44) contacting the front part (27) of the lock arm (23) in a height direction intersecting with the front-back direction at the standby position. The contact portion (78) stands up in the height direction from a front end part of the locking arm and then projects forward.

1. Field of the Invention
The invention relates to a connector.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. 2009-158263 discloses a connector with a first housing connectable to a second housing. A detector is assembled with the first housing and is movable between a standby position and a detection position located before the standby position. The detector has a deflection piece with a locking projection. The first housing has a lock arm with a lock hole, and the mating housing is provided with a lock projection.
A front part of the lock arm interferes with the lock projection in the process of connecting the two housings and this interference causes the lock arm to deflect. As a result, the locking projection enters the lock hole and contacts the front end of the lock hole, thereby keeping the detector in a state where a movement to the detection position is regulated.
The lock projection fits into the lock hole and pushes out the locking projection when the connection of the two housings is completed and the deflection piece is deflected and deformed as the lock arm returns. As a result, the detector can move to the detection position and the two housings are held in a state where separation of the two housings is regulated. Thus, an ability to move the detector from the standby position to the detection position indicates that the two housings are in a properly connected state.
In the above case, a front part of the deflection piece is in contact with the front part of the lock arm from above when the detector is at the standby position. Thus, the front part of the deflection piece can be displaced up together with the front part of the lock arm as the front part of the lock arm and the lock projection interfere with each other. Also, the integrity of the lock arm and the detector can be ensured in the process of deflecting the lock arm. However, the upper surface of an extending portion including the deflection piece is continuous at the same height over the entire length and the extending portion is relatively thick. Thus, opening dimensions of a guide space of the lock arm for receiving the extending portion tend to be large. As a result, there is little space to add a new structure to the lock arm, and there is a low degree of freedom in design.
The invention was completed based on the above situation and aims to provide a connector capable of ensuring the integrity of a lock arm and a detector in the process of deflecting the lock arm and enhancing a degree of freedom in design.


Provided is a non-volatile memory device including first and second, vertically stacked semiconductor substrates, a plurality of non-volatile memory cell transistors formed in a row on the first and second semiconductor substrates, and a plurality of word lines connected to gates of the plurality of non-volatile memory cell transistors. The plurality of non-volatile memory cell transistors are grouped into two or more memory cell blocks, such that a first voltage is applied to the first semiconductor substrate including a first memory cell block to be erased, and either (1) a second voltage less than the first voltage and greater than 0V is applied to the second semiconductor substrate not including the first memory cell block, or (2) the second semiconductor substrate not including the first memory cell block is allowed to electrically float.

The inventive concept relates to a non-volatile memory device, and more particularly, to a non-volatile memory device preventing current leakage and associated unexpected programming. The inventive concept is also related to an erase method for a non-volatile memory device.
Certain types of non-volatile memory, such as flash memory, are electrically erasable and programmable. Despite the relative ease of data manipulation provided by electrical programming and erasing, non-volatile memory is yet able to retain stored data in absence of applied power making it an excellent choice for many technical applications.

Non-volatile memory device and erase method


A minimally invasive sensing device, and method for its use, is disclosed which utilizes a light-conducting fiber having a localized textured site thereon, wherein a reagent is deposited. Interaction of the reagent with an analyte specific to the reagent produces a response, such as development of a colored product, which is detectable by means of a change in characteristics of a light beam transmittable through the fiber. By means of the textured site and its increased surface area, the sensitivity of the device is greatly enhanced, such that less than 5 microliters of a fluid is needed for an analysis. The sensor is particularly useful in blood glucose determinations, requiring smaller blood samples than flat strip devices.

The quantification of chemical and biochemical components in aqueous fluids, and particularly in biological fluids such as whole blood or urine and in biological fluid derivatives such as serum and plasma, is of ever increasing importance. Important applications exist in medical diagnosis and treatment and in the quantification of exposure to therapeutic drugs, intoxicants, hazardous chemicals and the like. These applications include the detection and quantification of an increasing variety of certain circulating antibodies, cancer-related metabolites, genetically derived chemical tracers, and hormones emitted during events such as pregnancy. In many instances, the amounts of materials being determined are minuscule--in the range of a microgram or less per deciliter--and readily analyzed only by means of complicated apparatus operated by skilled laboratory personnel. In such cases the results are generally not available for some hours or days after sampling. In other instances, there is often an emphasis on the ability of lay operators to perform analytical tests routinely, quickly and reproducibly in a nonlaboratory setting, with rapid or immediate information display.
One common medical test is the measurement of blood glucose levels by diabetics. Current teaching counsels diabetic patients to measure their blood glucose level from two to seven times a day, depending on the nature and severity of their individual cases. Based on the observed pattern in the measured blood glucose levels, the patient and physician together make adjustments in diet, exercise and insulin intake to better manage the disease. Clearly, this information should be available to the patient at the time of sampling.
This glucose determination typically entails the diabetic piercing the skin of his or her finger with a lance, followed by squeezing or expression of a blood droplet. The blood droplet is then transferred to a reagent pad or test strip. The amount of blood that is conveniently expressed from a finger prick is governed by the size and depth of penetration of the lance. Too small a nick results in an inadequately sized blood sample for the intended analysis. Pain is experienced in the lancing procedure, and the degree of pain is associated with the size and depth of penetration of the lance. Unfortunately, with current technology, a lancet size and required depth of penetration entails significant pain. The continual daily lancing of one's fingertips is a painful exercise necessarily tolerated by diabetics once or twice per day. More frequent testing than this, however, would bring on a serious problem of patient noncompliance, if required.
If the blood droplet size needed for a blood glucose determination can be significantly reduced, the pain associated with finger pricking can also be greatly reduced by reason of use of smaller lances and/or decreased depth of penetration into the flesh of the finger. There is indeed a need for an analytical sampling method, suitable for use by a diabetic patient, that requires less blood than current devices and methods, and which is therefore associated with less pain.
Determination of analytes in whole blood often involves colorimetric determinations utilizing color-generating reagents immobilized within reagent pads or porous media. The presence of red blood cells or other colored components in blood often interferes with such measurements. Exclusion of red blood cells and/or other blood cellular components has been practiced utilizing reagent pads with filterative or membranous layers specifically formed or laminated thereon. This tends to increase the complexity of such devices, as well as increasing the volume of blood that must be applied. Accordingly, in addition to the need for a smaller blood sample, a need also exists for a means of excluding cellular components of blood and body fluids without increasing the fluid sample size.
It is an object of this invention to provide a minimally invasive means of detecting and measuring analytes in both whole blood and other biological fluids. With regard to whole blood, it is a further object of this invention to provide a device capable of detecting and/or quantifying analytes without requiring a prior removal step for cellular blood components before blood contact with the device.
Another object of this invention to provide a device capable of detecting and/or quantifying a multiplicity of analytes in a single droplet of a bodily fluid.
Another object of this invention to provide a diabetic patient with a means of analyzing blood glucose concentrations in a manner that significantly reduces the pain associated with providing a sufficient blood sample for the glucose analysis.
These and other objects of the invention will be apparent to those skilled in this art from the following detailed description of preferred embodiments of the invention.


An absorbent article facilitating sensing the presence of a body exudate in the absorbent article includes an absorbent member; a sensor coil disposed on or in the article; and an electrical double-layer capacitor disposed on or in the article and in electrical communication with the sensor coil, wherein the capacitor is in fluid communication with the absorbent member. An absorbent article system also includes a detector circuit including an exciter coil configured for electromagnetic communication with the sensor coil, and sensor electronics configured to indicate the presence of a body exudate based on changes in the electromagnetic communication between the exciter coil and the sensor coil.

Absorbent articles such as diapers, training pants, incontinence products, feminine hygiene products, swim undergarments, and the like, conventionally include a liquid permeable body-side liner, a liquid impermeable outer cover, and an absorbent structure. The absorbent structure is typically located between the outer cover and the liner for taking in and retaining liquids (e.g., urine) exuded by the wearer. The absorbent structure can be made of, for instance, superabsorbent particles. Many absorbent articles, especially those sold under the trade name HUGGIES™ by the Kimberly-Clark Corporation, are so efficient at absorbing liquids that it is sometimes difficult to tell whether or not the absorbent article has been insulted with a body exudate, especially when the absorbent article is being worn by a newborn or other very young wearers. Insult amounts in such wearers tend to be very small. Other wearers might also produce very small insults.
Accordingly, various types of moisture or wetness indicators have been suggested for use in absorbent articles. The wetness indicators include various passive indicators such as indicator strips, printing, or other devices within each absorbent article. Wetness indicators can also include alarm devices that are designed to assist parents or attendants in identifying a wet diaper condition early on. These devices produce either a visual or an audible signal.
Electronic insult/status detection in absorbent articles mainly depends on resistive, capacitive, inductive or optical sensors that are placed at the insult locations. All these sensors require either an electronic circuit that has to be directly in contact with the sensing electrodes, or conventional sensor components of limited effectiveness and range. These sensing electrodes placed at the insult locations can monitor the insult by measuring any changes in its resistance, capacitance or impedance characteristics. This makes it difficult to monitor the wetness/status of articles that are in intimate contact with the human body such as feminine hygiene products. Tampon users are often concerned with the status of the article. An efficient technology to monitor the status, fullness, and/or time-to-change status is still an unmet challenge.
Problems, however, have been encountered in designing a signaling device that can be used as desired but that does not appreciably increase the cost of each absorbent article, while providing a meaningful signal to the caregiver.

Contactless passive sensing for absorbent articles


Carbonyl compound contaminants are removed from hydrocarbon streams containing olefins for use, for example, in the process for the skeletal isomerization of olefins by pretreating the hydrocarbon stream by passing it over an acidic catalyst at elevated temperatures in the range of 100-400.degree. C. under conditions to react the carbonyls to form reaction products which are deposited onto the catalyst.

1. Field of the Invention
The present invention relates generally to a process for the removal of carbonyl contaminants in hydrocarbon streams. More particularly the invention relates to the removal of carbonyl compounds from a stream containing at least aldehydes, ketones or esters. More particularly the invention relates to a removal process wherein the carbonyl compounds, including the aldehydes and ketones, undergo reactions in the presence of an acidic catalyst and at least, a part of the reaction products are adsorbed/absorbed on the catalyst.
2. Related Art
Linear olefins are isomerized to branched olefins in the presence of an acidic catalyst such as molecular sieves, silica-alumina, fluorinated alumina, etc. The tertiary olefins that are a product of the isomerization are useful as feed to a tertiary ether process or to an alkylation process.
When a stream containing both linear and branched olefins is fed to an etherification process the branched olefins preferentially react with an alcohol to produce the tertiary ether. In the case of isobutene and methanol the reaction product is methyl tertiary butyl ether (MTBE) and in the case of isopentene (isoamylene) and methanol the product is tertiary amyl methyl ether (TAME). Both ethers are useful as gasoline additives.
The unreacted linear olefins, either the normal butenes or normal pentenes, can be used in a cold acid alkylation process or may be isomerized to branched olefins and recycled back to the etherification process. In either case, the normal olefins from the initial etherification may contain trace amounts of the unreacted alcohol which act as catalyst inhibitor in the isomerization process or consume acid in cold acid alkylations. Aldehydes and ketones may be contained in other feedstreams to a skeletal isomerization process. For example, the C.sub.5 stream from a Fischer-Tropsch synthetic fuel process contains small amounts of acetone, propionaldehyde, methyl ethyl ketone and butylaldehyde as well as alcohols. These carbonyl compounds render molecular sieve skeletal isomerization catalysts, such as zeolites, e.g., ferrierite, useless after only a few hours on stream. In an integrated process for etherification and isomerization as disclosed in U.S. Pat. Nos. 5,210,327 and 5,276,212, the linear olefins are treated to remove the alcohol, water and nitrogen compounds prior to the isomerization. The alcohol and nitrogen compounds are removed by adsorption on zeolitic molecular sieves by a process disclosed in U.S. Pat. No. 4,814,517. Any acetone or acetonitrile in the feed is removed by a water wash prior to the etherification.

Process for the removal of carbonyl compounds in isomerization feed streams


A cross-linkable and cross-linked organosilicon polymer which is prepared from a mixture of a reactive polysiloxane resin having both reactive carbon-carbon double bonds and silicone-hydrogen groups, characterized by alternating structures of polycyclic polyene residue and cyclic (or tetrahedral) polysiloxane residue, and either vinyl terminated fluorine-containing polysiloxane or vinyl terminated phenyl-substituted siloxane. In an alternative embodiment, the polymer comprises a mixture of vinyl terminated phenyl-substituted polysiloxane and vinyl functional fluorosilicone elastomer with the cross-linkable and cross linked organosilicon polymer.

It is known in the art to prepare cross-linked and cross-linkable silicone elastomers which are mainly comprised of two types of liquid polysiloxanes; one having vinyl (or general C═C) attached to the main chain and the other having hydrogen directly attached to silicone atoms. The addition curing (or crosslinking) reaction to form elastomeric materials occurs through hydrosilation in the presence of platinum or other metal-containing catalysts under room temperature or heating conditions. The substitution groups attached to the silicone chain can be methyl, phenyl, or fluoroalkyl (mostly trifluoropropyl). The fluoroalkyl substituted silicone (fluorosilicone) generally displays good chemical resistance and is commonly used as coating, potting or encapsulation material to protect electric/electronic components and assemblies.
The preparation of curable organosilicon prepolymers or cross-linked thermosetting polymers through a hydrosilation reaction of polycyclic polyene (providing an active C═C) and reactive cyclic polysiloxane or tetrahedral siloxysilane (providing SiH) in the presence of platinum-containing catalysts under heating is also known in the art. The resulting fully cross-linked materials display high rigidity and brittleness, a relatively high Tg, very high temperature resistance, water insensitivity and oxidation resistance. Examples of these types of polymers are found in U.S. Pat. Nos. 4,902,731 and 4,877,820.
Attempts have been made to reduce the brittleness and rigidity and increase the toughness of such polymers. U.S. Pat. No. 5,171,817 discloses such an organosilicone polymer in which reactive siloxane elastomers having carbon-carbon double bonds are added to the composition to form discontinuous phases in the rigid continuous polymer matrix after curing. For example, unsaturated diphenyl dimethyl siloxane elastomers are utilized to increase toughness and adhesion without reducing any of the other properties of the polymer. U.S. Pat. No. 5,196,498 discloses the use of a second silicone as a modifier to reduce the viscosity and brittleness of the crosslinked polymers. The second silicone compound, which has reactive hydrocarbyl group, is a cyclic siloxane and most preferably tetravinyltetramethyl cyclotetrasiloxane or pentavinylpentamethyl cyclopentasiloxane.
Accordingly, it would be advantageous for a polymer to have certain properties of known polymers without the brittleness and high rigidity that are usually associated therewith. It would be further advantageous for the polymer to have high acid and fuel resistance such that it would be suitable for use in fields which require polymers having more flexibility.
One potential use of such polymers is in the automotive industry as an encapsulant for items such as sensors, and especially as an encapsulant for pressure sensors. Such encapsulants must have an extremely high resistance to acids and fuels. For example, two fuels commonly utilized for material evaluation by the automobile industry, Fuel C and Fuel CM85, both cause polymer degradation to many known polymers. Fuel C is a hydrocarbon fuel which is approximately 50% by volume isooctane and 50% by volume toluene. Fuel CM85 comprises Fuel C containing 85% by volume methanol. In addition many materials are tested by the automotive industry for their resistance to used synthetic oil, which also causes polymer degradation. For the purpose of this patent, this is defined as Mobile 1 Oil, which has been used to lubricate an automotive engine for a minimum of 3,000 miles.

National Starch and Chemical Investment Holding Corporation


The invention includes a method and apparatus for scheduling packet transmissions on a data channel from a base transceiver station to a plurality of wireless terminals. The method includes, in response to detecting an available timeslot, computing utilization evaluation values for the respective media sub-streams using data rate feedback information from the wireless terminals and respective average data rates associated with respective media sub-streams, selecting one of the media sub-streams having an associated utilization evaluation value indicative of a best available channel utilization for the data channel, and transmitting a packet from the selected media sub-stream toward at least one wireless terminal belonging to a media sub-group associated with the selected media sub-stream. An average data rate associated with each media sub-stream is updated at each timeslot.

To distribute streaming multimedia content to multiple mobile devices, service providers typically use the cost-effective broadcast multicast architecture of Third Generation (3G) wireless networks. Within a multicast group, mobile terminals are heterogeneous in terms of terminal capability and channel condition. In the absence of feedback information from the mobile terminals, in order to provide adequate cell coverage, existing data transmission scheduling schemes, assuming that there is always at least one mobile terminal located at the edge of the cell, use a fixed data rate in each time slot. Disadvantageously, although such data transmission scheduling schemes ensure adequate wireless coverage within the cell, data throughput of mobile terminals with good respective channel conditions (e.g., mobile terminals located close to the Base Transceiver Station) is limited.

Method and apparatus for improved multicast streaming in wireless networks


In order to easily perform a timing test on a memory interface included in a semiconductor device so as to satisfy a restriction on latency, the present invention provides a semiconductor device with the memory interface including: a clock output terminal that outputs a clock signal associated with an operation of a memory connected to the memory interface; a command terminal that outputs a command signal associated with control of a state of the memory; a data terminal that exchanges a data signal with the memory; and a data strobe terminal that exchanges a data strobe signal for establishing the data signal. This semiconductor device includes a testing terminal that outputs in advance a signal for starting a test on the memory interface apart from the command signal.

1. Field of the Invention
The present invention relates to technologies of a semiconductor device, a testing method and a manufacturing method thereof, etc. and, more particularly, to a semiconductor device technology suitable for testing a high-speed memory interface which the semiconductor device has. Also, the present invention relates to technologies for a method of testing an electric characteristic of a memory interface included in a semiconductor device and a method of manufacturing a semiconductor device with a memory interface.
2. Description of the Related Art
Semiconductor memories widely used in personal computers or various electric appliances are Synchronous Dynamic Random Access Memories (hereinafter referred to as "SDRAMs"). The SDRAM includes a Single Data Rate SDRAM (hereinafter referred to as "SDR-SDRAM") and a Double Data Rate SDRAM (hereinafter referred to as "DDR-SDRAM"), and the high-speed DDR-SDRAM has been widely used. For data exchange with such a DDR-SDRAM, a semiconductor device (semiconductor integrated circuit) has recently incorporated therein a high-speed memory interface (circuit unit).
Operations of a semiconductor device including a memory interface and a semiconductor memory will be briefly described below by using FIGS. 5 to 7, in an exemplary case where the DDR-SDRAM is used as the semiconductor memory.
FIG. 5 depicts a general outline of a connection between a DDR-SDRAM 50 as a semiconductor memory and a semiconductor device 40 with a memory interface supporting that semiconductor memory. Note that unless otherwise specified, the "semiconductor device" means a semiconductor device with a memory interface. The semiconductor device 40 has various signal terminals as a memory interface, such terminals including an operation clock terminal 12 that outputs an operation clock (denoted as "MCLK"), a memory command terminal 13 that outputs a memory command, a data terminal 14 that inputs and outputs data (denoted as "DQ"), and a data strobe terminal 15 that inputs and outputs data strobe (denoted as "DQS"). In normal use, each of the terminals (12 to 15) of the memory interface of the semiconductor device 40 is connected to each corresponding terminal on a side of the DDR-SDRAM 50 via a signal line (transmission line).
MCLK is a clock signal for operation of the DDR-SDRAM 50. The memory command is a command signal for controlling the state of the DDR-SDRAM 50. The memory command comprises a plurality of signal lines and, based on the state of each of these signals (hereinafter "High-and-Low" or "described H/L"), controls the state of the DDR-SDRAM 50, such as data write ("WRITE") and data read ("READ"). The DQ is a signal for data exchange with the DDR-SDRAM 50. The DQS is a signal for determining the DQ and a signal for notification of input/output timing.
Note that, in FIG. 5, for the purpose of simplifying the description of a connection pattern of the semiconductor device 40 with the memory interface and the DDR-SDRAM 50 for general use, a bus representation is not used for each signal and termination resistors between the semiconductor device 40 and the DDR-SDRAM 50 and others are not shown.
FIG. 6 depicts a general outline of signals (including signal input/output timing) when data is written from the semiconductor device 40 to the DDR-SDRAM 50. "T1" and the like represent time. (a) to (d) in FIG. 6 correspond to signals outputted from the relevant terminals of the semiconductor device 40.
(a) MCLK 2 represents a clock signal at a frequency corresponding to the operation speed of the DDR-SDRAM 50, and is outputted from the semiconductor device 40 to the DDR-SDRAM 50. Note that, in the present example, an inverted phase clock is omitted, and the clock signal is represented as one line. (b) memory command 3 in this case is "WRITE" 3a corresponding to a data write state setting signal. (c) DQ 4 represents a write data signal outputted from the semiconductor device 40. D1 to D4 respectively denote write data. (d) DQS 5 is outputted in accordance with DQ 4 to determine timing for establishing DQ 4 in the DDR-SDRAM 50.
From the semiconductor device 40, for example, "WRITE" 3a is outputted as (b) memory command 3 so as to establish a rising edge of MCLK 2 at a time T3 (as represented by a triangle in the drawing). The DDR-SDRAM 50 receiving "WRITE" 3a makes a transition to a data write state. When the memory interface supports the DDR-SDRAM, the semiconductor device 40 outputs (c) DQ 4 and (d) DQS 5 after outputting "WRITE" 3a (T3) and one clock after MCLK 2 (T4). The DDR-SDRAM 50 receives these DQ 4 and DQS 5, internally latches DQ 4 at timing of DQS 5 (rising and trailing), and then retains each piece of data (D1 to D4).
As for a relation between DQ 4 and DQS 5 in the DDR-SDRAM 50, a set-up time tDS and a hold time tDH are defined. This timing definition, the memory interface of the DDR-SDRAM 50, and others are standardized by Joint Electron Device Engineering Council (hereinafter referred to as "JEDEC"), which is a US industrial organization for facilitating standardization of electronic components.
FIG. 7 depicts a general outline of signals when the semiconductor device 40 reads data from the DDR-SDRAM 50 to the semiconductor device 40. As with the above, (a) MCLK 2 represents a clock signal at a frequency corresponding to the operation speed of the DDR-SDRAM 50. (b) memory command 3 in this case is "READ" 3b corresponding to a data read state setting signal. (c) DQ 4 represents a read data signal outputted from the DDR-SDRAM 50. D1 to D4 respectively denote read data. (d) DQS 5 is outputted in accordance with DQ 4 to determine timing for establishing DQ 4 in the semiconductor device 40.
From the semiconductor device 40, for example, "READ" 3b is outputted as (b) memory command 3 so as to establish a rising edge of MCLK 2 at a time T3 (as represented by a triangle in the drawing). The DDR-SDRAM 50 receiving "READ" 3b makes a transition to a data read state, that is, a retained data output state. Then, the DDR-SDRAM 50 outputs (c) DQ 4 (for example, retained data at the time of writing data) and (d) DQS 5 in synchronization with (a) MCLK 2. The semiconductor device 40 then receives these (c) DQ 4 and (d) DQS 5, and retains DQ 4 at timing of DQS 5.
When DQ 4 is read from the DDR-SDRAM 50, as for its read timing, apart from the set-up time and the hold time as described above regarding the time of data writing, there is a timing definition of "/CAS latency" (hereinafter abbreviated as "CL" and, particularly, also as "/CAS read latency", where "/" represents a sign indicative of an inverted phase). "CAS" is an abbreviation of column address strobe. For example, in the case of DDR-SDRAM 50 of the type defined as CL=2, there is a restriction in which, DQ 4 and DQS 5 have to arrive at the semiconductor device 40 by two rising edges of MCLK 2, that is, at a time T5 after (b) "READ" 3b of the memory command 3 is outputted. In FIG. 7, for example, an example of the case of CL=2 is shown.
Also, in FIGS. 6 and 7, four consecutive pieces of data D1 to D4 are shown as DQ 4. This is defined by a burst length (hereinafter abbreviated as "BL") of the DDR-SDRAM (50), and, by way of example, the case of being defined as BL=4 is shown. The consecutive pieces of data (DQ 4) for BL defined in the DDR-SDRAM (50) are collectively received.
There are a plurality of types of the DDR-SDRAM 50 depending on the elements including CL, BL, and further the operation speed (clock frequency of MCLK 2). The memory interface of the semiconductor device 40 is one suitable for the type of the semiconductor memory (DDR-SDRAM 50) to be connected.
Note that detailed specifications of the above-described memory (DDR-SDRAM) and memory interface and others are described in "Usage of DDR SDRAM—User's Manual", Document No. J0234E30 (Ver. 30), issued on April, 2002, Elpida Memory, Inc., URL:    <http://www.elpida.com/ja/products/index.html>,    <http://www.elpida.com/pdf/j0234E30.pdf>.
In the test on the memory interface of the semiconductor device 40 as described above, a test on timing that complies with the specifications of the JEDEC is required due the way of usage described above. Subjects of the timing test may include the set-up time/hold time, as well as whether CL is satisfied.
In general, for electric characteristic tests on the semiconductor device, some type of semiconductor device or semiconductor test system is used. However, the memory interface of the semiconductor device has a high-speed data transfer rate such as 400 Mbps, and is therefore required to be tested by a semiconductor testing device operable at a high speed. Moreover, if the data transfer rate is 400 Mbps, for example, one data width is 2.5 ns (= 1/400 Mbps), and therefore the set-up time/hold time is 1.25 ns. Also, if it is assumed that a timing test is required to be performed with precision of one-tenth of the set-up time/hold time, a semiconductor testing device guaranteed with timing precision of 125 ps is required.
However, such a semiconductor testing device operable at a high speed and with high timing precision is extremely expensive in comparison with general semiconductor testing devices, thereby posing a problem that manufacturing costs of semiconductor devices cannot be reduced.
Japanese Patent Laid-Open Publication No. 2003-98235 discloses a technology for conducting a timing test on a memory interface by using a semiconductor testing device with an operation speed slower than the memory interface included in a semiconductor device.

Semiconductor device, testing and manufacturing methods thereof


The present invention relates to a high-output apparatus for manufacturing a polycrystal silicon ingot for a solar cell, and more particularly, to an apparatus for manufacturing a polycrystal silicon ingot by means of heating and melting raw silicon in a vacuum chamber, and then cooling the molten silicon, wherein the apparatus comprises: a plurality of crucibles arranged so as to be horizontally separated from one another within the vacuum chamber, and in each of which raw silicon is filled for manufacturing polycrystal silicon ingots; heating means provided at the outside of each of the crucibles so as to heat each crucible and melt the raw silicon filled therein; and cooling means for cooling the crucibles, so as to enable the silicon melted by the heating means to be cooled in one direction and be formed into polycrystal ingots.

Recently, solar photovoltaic power generation using crystalline silicon solar cells passes a test stage and attains a commercialization stage due to advantages thereof such as pollution-free, safety, high performance, and reliability.
As a result thereof, in several nations such as German, Japan, and Korea, high capacity of solar photovoltaic power generation is performed to several thousands to several ten thousands kW.
Currently, solar cells used in solar photovoltaic power generation are manufactured generally using one of single crystal ingots manufactured by Czochralski method and polycrystal silicon ingots manufactured by Bridgman method. To continuously increase large-scale capacity and economical feasibility, it is considered to more lower the cost of silicon ingots and substrates and to increase productivity.
On such grounds, particularly, there are provided a lot of efforts to efficiently produce polycrystal silicon ingots whose properties are not largely deteriorated rather than that of single crystals, capable of reducing cost thereof.
Manufacturing polycrystal silicon ingots for a solar cell basically has "directional solidification" as properties.
A crucible manufactured using one of quartz and graphite is filled with raw silicon for solar cells. The raw silicon is melted at a temperature of 1420° C. or more and heat of solidification of silicon is removed in a certain direction toward a bottom of the crucible, thereby spreading solidification from the bottom of the crucible to a top of the crucible, which is a directional solidification process.
Ingots obtained as a result of a well-controlled directional solidification process has a columnar structure in which a large number of single crystal columns are coupled with one another in one direction in such a way that there is provided a structure capable of collecting electrons generated by photos toward an electrode without loss, identical to single crystals, when manufacturing a substrate vertical, to a crystal growth direction.
General polycrystal silicon ingots for solar cells with commercial scale have a size of about 400 to 450 kg. To embody high quality, general polycrystal silicon ingots are manufactured one by one at a time in a batch. Generally, there are required a long process for two days or more, a large amount of power consumption, and expensive installation costs.
Technical core is to manufacture polycrystal ingots suitable for solar cells by melting and directionally solidifying raw silicon, whose crystal structure is a columnar structure, whose grain size is large, having a high quality, in which crystalline defects and impurities are less enough.
To embody this, it is required to accompany an optimal design for a heater forming a hot zone of an apparatus for manufacturing ingots, an insulator, a bottom heat transfer system for directional solidification, inert gas, a vacuum system, coated crucibles, a system against a leakage of melted silicon, and optimization of variables in process such as silicon melting and solidification speed and heat treatment speed.
Technical developments in the art have focused on embodying the quality of ingots and also increasing productivity and economic feasibility by promoting improvements in such apparatuses and processes.
In such situation, a primary direction of present technology development is to more increase a size of ingots produced in a batch at a time. However, as another way to increase productivity and reduce cost, there may be considered a way of producing a plurality of ingots in a batch at a time. Thereupon, an aspect of the present invention is to provide a new apparatus for manufacturing ingots and a method of using the apparatus, the apparatus capable of producing a plurality of ingots simultaneously with the same process time, and to provide additional technologies according thereto.

High-output apparatus for manufacturing a polycrystal silicon ingot for a solar cell

Korea Research Institute of Chemical Technology


An outlet plate fitting configured for attaching a secondary component to a fluid pipe section. The fluid pipe section includes opposed flanges that define a receiving groove having a bottom surface. The outlet plate fitting includes a main body, an engagement platform connected to and at a distance from the main body, and a bore extending through the main body and the engagement platform. A first surface of the engagement platform faces away from the main body and is a planar surface with a seal member positioned about the bore. A second surface of the engagement platform faces toward the main body and has a ramped surface, such that rotation of the engagement platform in a first direction within the receiving groove causes the planar surface and seal member into sealing engagement with the bottom surface of the receiving groove.

The present invention relates to a system for channeling and distributing fluids which are either gaseous or liquid, under pressure or under vacuum, and it pertains more specifically to a system of elements for a modular connection, in line or at an angle, of pipelines which consist of extruded pipe sections for such units.
The use of extruded hollow bars made of aluminum or the alloys thereof as pipelines in the units for channeling and distributing gaseous or liquid fluids, such as air, gas, oils, water, etc. has already been proposed. These bars have usually at least one longitudinal hole and grooves along the sides of the perimeter defined by longitudinal beads or fins obtained from the extrusion. The bars thus shaped can be connected, in line or at an angle, with other identical hollow bars with the aid of round tubular joints, which are inserted in a fluid-tight manner into the hole of the adjacent bars and with connecting plates which are joined and are locked by means of screws in the outer grooves of the bars to be connected.
However, such a method for constructing pipelines for fluids is complex, labor-intensive, burdensome and not without disadvantages. This method involves the use of extruded hollow bars that have a relatively large and elaborate cross section given the presence of the fins or the faces which must delimit the outer grooves for anchoring the connecting plates. Thus, the bars will be relatively bulky and heavy, and given their profile, are difficult, if not impossible, to bend, where necessary, without modifying the profile of the section in the bent part. In addition, the connecting plates are also complex and require counter-plates for the locking in the outer grooves of the section.


A semiconductor device (10) includes a semiconductor die (20) and an inductor (30, 50) formed with a bonding wire (80) attached to a top surface (21) of the semiconductor die. The bonding wire is extended laterally a distance (L30, L150) greater than its height (H30, H50) to define an insulating core (31, 57). In one embodiment, the inductor is extended beyond an edge (35, 39) of the semiconductor die to reduce loading.

The present invention relates in general to semiconductor devices and, more particularly, to integrated circuits that are formed with a semiconductor die and inductors housed in the same semiconductor package.
Electronic system manufacturers continue to demand integrated circuits with increased levels of functionality and a physically smaller size. The demand is particularly evident with portable wireless communications devices, whose size typically is limited by hundreds of discrete passive components that have not yet been successfully integrated due to their operation at frequencies of 2.5 gigahertz or more. High frequency inductors have proven to be particularly difficult to integrate on a semiconductor die because of the performance degradation resulting from the parasitic substrate capacitance and eddy currents.
One previous approach to integrating inductors has been to form planar spiral inductors and their associated circuitry on the same semiconductor die. However, the quality factor of the planar spiral inductors is low due in part to the parasitic substrate capacitance and eddy currents mentioned above. In addition, the additional processing steps and large die area occupied by the planar inductors has a high cost that has made this approach uneconomical in many applications.
Another approach has been to house a discrete chip inductor and a semiconductor die into the same integrated circuit package. The chip inductors have a high quality factor but the component placement and solder reflow processing step needed to mount the inductor also result in a high overall fabrication cost. Moreover, existing discrete chip inductors have a large physical size that increases the profile of the packaged integrated circuit and precludes their use in many applications.
Hence, there is a need for an integrated circuit and method-of integrating inductors that combines a low fabrication cost, small physical size and high performance.

Semiconductor device with wire bond inductor and method

Semiconductor Components Industries, L.L.C.


A shock sensor detects shocks from all directions in a plane. A shock-sensing member extends longitudinally and is housed in a case. The shock-sensing member is rotatably supported by a supporting pin at an off-center point in terms of mass of the shock-sensing member. The shock-sensing member has a magnet mounted on each of two diametrically opposing ends of the shock-sensing member. Each magnet opposes a magnetoresistive effect element fixed in the case. The magnetoresistive effect element may include four elements electrically connected in a bridge configuration. When the shock-sensing member receives a shock, the shock-sensing member rotates about the supporting member causing the magnetoresistive effect element to be subjected to a change in the magnetic field of the magnet. The output of the magnetoresistance changes with changes in the magnetic field and is processed by an output circuit which in turn outputs a sensor output accordingly.

1. Field of the Invention
The present invention relates to shock sensors and more particularly to a shock sensor for use in an air bag system for automobiles.
2. Description of Related Art
An air bag system is employed in an automobile in order to protect the driver from a shock when the automobile collides with another automobile or the like. A shock sensor detects a shock and outputs a detection signal. The detection signal activates a firing device of an air bag which in turn causes the air bag to quickly inflate to protect the driver from the shock.
Prior art shock sensors are disclosed in, for example, Japanese Patent Preliminary Publications No. 7-198738 and No. 8-29444.
FIG. 16 illustrates a conventional shock sensor.
Referring to FIG. 16, a magnet 16 is housed in a case 11 and attached to one end of a shock-sensing element 15 which is swingably supported on a pin 14. The shock-sensing element 15 is normally at its neutral position shown in FIG. 16 so that the magnet 16 is normally positioned directly over a magnetic element 17 fixedly mounted in the case 11. The neutral position is a position where the shock-sensing element 15 is at rest when no shock is applied thereto. Mounted on both sides of the magnetic element 17 are reed switches 12 and 13 which are closed when the magnet 16 moves to positions over the reed switches 12 and 13. The reed switches are normally open since the magnet 16 is directly over the magnetic element 17.
If a shock is applied to the shock sensor in a direction shown by arrow P, the shock-sensing element 15 acquires a momentum and swings counterclockwise. Thus, the shock-sensing element 15 is moved out of its neutral position. Thus, the magnet 16 moves into an area where the reed switch 13 is closed.
However, the principle of the conventional art reed switch type shock sensor dictates that the sensor is mounted in such a way that the shock-sensing element 15 is always suspended vertically. In addition, the sensor detects shocks only in a narrow range of direction in which the shock-sensing element 15 can swing sufficiently. Thus, shocks in any other directions outside of the range are not detected properly. The shock is converted into an electrical signal in terms of on-off operation of the reed switches 12 and 13. Use of a reed switch is an obstacle to miniaturizing a shock sensor. Another problem with the conventional art sensor is that the detection signal of the shock sensor is outputted only in limited signal form since the reed switches in FIG. 16 are normally open.

Shock sensor with rotating magnetorestrictive effect element


A transmitting/receiving circuit includes, in part, at least one transceiver, and at least two receiving channels forming a diversity receiver. One of the receiving channels includes, in part, a saw filter, an amplifier, and a frequency converter. The other receiving channel includes, in part, an amplifier, a frequency converter, and a received signal strength indicator (RSSI) adapted to detect signals transmitted by the transceiver. The RSSI is optionally coupled to an input terminal of its associated amplifier. The receiver further includes, in part, at least one processor operative to combine signals processed through the first and second receiving channels using a weight the processor assigns to the signal received by the second receiving channel in accordance with a strength of the blocker signal that the RSSI detects. The second receiving channel optionally includes an RSSI.

Antenna diversity can significantly improve the performance of a wireless receiver system but also increases the cost. In order to keep the cost down, most wireless receiver systems in consumer applications use a single antenna receiver. In many handset units, the components that cause cellular transmissions (such as CDMA) are located in relatively close proximity of other wireless receivers (such as WiFi or mobile TV receivers) disposed in the handset unit. FIG. 1 shows a number of processing units of a conventional handset 100. Handset 100 is shown as having a CDMA cellular unit 110, a Bluetooth transceiver 120, a WiFi or WiMax transceiver 130, and a mobile TV receiver 140. Each of these four units is shown as having a single dedicated antenna.
FIG. 2 shows a handset unit 200 that includes, in part, a cellular CDMA transceiver 210 having an antenna 215, and a mobile TV diversity receiver 220 having antennas 225 and 230. Because of their close proximity, transmissions from cellular transceiver 210 often couple significantly to receiver 220. This problem is further compounded by the relatively high power that transceiver 210 requires to transmit data.
Referring to FIG. 1, in order to minimize the impact of the strong transmissions by CDMA cellular unit 110, on the receivers 120, 130, and 140, conventional handset units typically include a filter (that has a relatively sharp filtering characteristics) at the input of the receivers (e.g., WiFi or Mobile TV receivers.) This filtering operation is typically performed using a SAW filter which is costly and consumes a relatively large space.
FIG. 3A shows a conventional diversity receiver system 300 having two receiving channels, namely a first receiving channel 320 and a second receiving channel 340. First receiving channel 320 is shown as including a low-noise amplifier 322, a mixer 324, a filter 326, and an amplifier 328. Likewise, second receiving channel 340 is shown as including a low-noise amplifier 342, a mixer 344, a filter 346, and an amplifier 348. Diversity baseband processor 310 combines the signals it receives from first and second receiving channels 320 and 340, using any one of a number of well-known algorithms, to generate and output the sensed signal.
FIG. 3B shows a conventional diversity receiver system 350 having a pair of receiving channels 320 and 340 that are similar to the receiving channels 324 320 of FIG. 3A. Diversity receiver system 350 includes a first diversity baseband processor 325 that receives the output signal of amplifier 328, and a second diversity baseband processor 345 that receives the output signal of amplifier 348. Diversity baseband processors 325 and 345 communicate with one another to asses, in conformity with a selected diversity algorithm, the signal quality or signal-to-noise ratio (SNR) from antennas 306, 308, and to weight the signal received from each channel based on this assessment. For example, poor SNR from antenna 308 compared with the SNR from antenna 306 causes the baseband processors to assign less weight to the signal from antenna 308 than the signal from Antenna 306.
FIG. 4 shows an example of the EM radiation spectrum seen by a handset unit such as handset unit 200 shown in FIG. 2. Signal 420 is transmitted by transceiver 210 and is commonly referred to as the blocker signal. Signal 430, which has a frequency that is close to the frequency of signal 420, is the desired TV channel being received by receiver 220. Signal 420 is often a strong signal and thus can severely interfere with the reception of signal 430.
To attenuate the blocker signals, a SAW filter is commonly used in the receiving channel. FIG. 5 shows a typical transfer function 510 of a SAW filter, which as is seen, has a sharp frequency roll-off to attenuate the blocker signal 420. SAW filters are commonly used in front of sensitive receivers to provide this effect. One disadvantage of SAW filters is that they are costly and introduce non-negligible loss, thereby directly degrading the noise figure of the receiver.
Conventional diversity receivers use a SAW filter in each of the diversity channels. FIG. 6 shows a handset unit 600 that includes diversity receiving channels 610, 630, diversity baseband processor 650, and a transceiver 660. Receiving channel 610 includes a SAW filter 612, a low-noise amplifier (LNA) 614, a mixer 616, a filter 618, and an amplifier 620. Receiving channel 640 includes a SAW filter 632, an LNA 634, a mixer 636, a filter 638, and an amplifier 640. Baseband processor 650 receives the output signals of amplifiers 620 and 640, and combines them in accordance with any one of a number of well-known algorithms to generate and output the sensed signal that is received. As was described above, the inclusion of SAW filter 632 in the second receiving channel 630 increases the cost of handheld unit 600 and is thus undesirable.


To provide a magnetic bearing device capable of lowering the costs required for the manufacture, installation, or the like of a turbo molecular pump by reducing the number of elements of an amplifier circuit that drives, through excitation, electromagnets as well as the number of wires of a cable that connects the each electromagnet and the amplifier circuit to each other, and a turbo molecular pump with the magnetic bearing device mounted thereto. One end of an electromagnet coil is connected to a common node. Also, the other end thereof is connected to an amplifier circuit composed of one transistor and one diode. Further, the one end of the electromagnet coil is common with respect to each of the electromagnets, and the common node R is controlled by an intermediate-voltage maintaining circuit so as to maintain an intermediate voltage.

1. Field of the Invention
The present invention relates to a magnetic bearing device and a turbo molecular pump with the magnetic bearing device mounted thereto. More specifically, the present invention relates to a magnetic bearing device capable of lowering the costs required for the manufacture, installation, or the like of a turbo molecular pump by reducing the number of elements of an amplifier circuit that drives, through excitation, electromagnets as well as the number of wires of a cable that connects the each electromagnet and the amplifier circuit to each other, and to a turbo molecular pump with the magnetic bearing device mounted thereto.
2. Description of the Related Art
With the development of electronics in recent years, demands for semiconductors for forming memories, integrated circuits, etc. are rapidly increasing.
Those semiconductors are manufactured such that impurities are doped into a semiconductor substrate with a very high purity to impart electrical properties thereto, or semiconductor substrates with minute circuit patterns formed thereon are laminated.
Those manufacturing steps must be performed in a chamber with a high vacuum state so as to avoid influences of dust etc. in the air. This chamber is generally evacuated by a vacuum pump. In particular, a turbo molecular pump is widely used since it entails little residual gas and is easy of maintenance.
The semiconductor manufacturing process includes a number of steps in which various process gases are caused to act onto a semiconductor substrate, and the turbo molecular pump is used not only to evacuate the chamber but also to discharge those process gases from the chamber.
Further, in equipment for an electron microscope etc., a turbo molecular pump is used to create a high vacuum state in the chamber of the electron microscope etc. in order to prevent refraction etc. of an electron beam caused by the presence of dust or the like.
Such a turbo molecular pump is composed of a turbo molecular pump main body for evacuating the chamber of a semiconductor manufacturing apparatus, an electron microscope, or the like, and a control device for controlling the turbo molecular pump main body.
FIG. 14 is a vertical sectional view of the turbo molecular pump main body.
In FIG. 14, a turbo molecular pump main body 100 includes an outer cylinder 127 with an intake hole 101 formed on top thereof. Provided inside the outer cylinder 127 is a rotor 103 having in its periphery a plurality of rotor blades 102a, 102b, 102c, . . . serving as turbine blades for sucking and discharging gas and formed radially in a number of stages.
At the center of the rotor 103, a rotor shaft 113 is mounted with being supported in a levitating state in the air and controlled in position, for example, by a 5-axis control magnetic bearing.
Upper radial electromagnet 104 includes four electromagnets arranged in pairs in X- and Y-axis and plus- and minus-side directions (although not shown in the drawing, those electromagnets are referred to as 104X−, 104Y+, and 104Y−, as necessary). Further, there is provided an upper radial sensor 107 constituted of four electromagnets arranged in close proximity to and in correspondence with the upper radial electromagnets 104. The upper radial sensor 107 detects radial displacement of the rotor 103, transmitting a detection signal to a control device 200 (shown in FIG. 15).
In this control device 200, the upper radial electromagnets 104 are excited and controlled by a magnetic bearing control circuit 201 having a PID adjusting function, on the basis of a displacement signal detected by the upper radial sensor 107, thus the radial position of the upper portion of the rotor shaft 113 being adjusted.
The rotor shaft 113 is formed of a high-magnetic-permeability material (e.g., iron) and is adapted to be attracted by the magnetic force of the upper radial electromagnets 104. Such adjustment is conducted independently in the X-axis direction and the Y-axis direction.
Further, lower radial electromagnets 105 and a lower radial sensor 108 are arranged in the same way as the upper radial electromagnets 104 and the upper radial sensor 107. Like the radial position of the upper portion of the rotor shaft 113, the radial position of the lower portion of the rotor shaft 113 is adjusted (the lower radial electromagnets 105 are similarly referred to as 105X+, 105X−, 105Y+, and 105Y−, as necessary).
Further, axial electromagnets 106A and 106B each are arranged on the upper and lower sides of a metal disc 111 provided in the lower portion of the rotor shaft 113. The metal disc 111 is formed of a high-magnetic-permeability material such as iron. To detect axial displacement of the rotor shaft 113, an axial sensor 109 is provided, which transmits an axial displacement signal to the control device 200.
The axial electromagnets 106A and 106B are excited and controlled by the magnetic bearing control circuit 201 having a PID adjusting function on the basis of the axial displacement signal. The axial electromagnet 106A upwardly attracts the magnetic disc 111 by the magnetic force, and the axial electromagnet 106B downwardly attracts the magnetic disc 111.
In this way, the control device 200 has a function to appropriately control the magnetic force exerted on the metal disc 111 by the axial electromagnets 106A and 106B to magnetically levitate the rotor shaft 113 in the axial direction, thereby retaining the rotor shaft 113 in the space in a non-contact state.
Note that descriptions will be given later on the magnetic bearing control circuit 201.
A motor 121 is equipped with a plurality of magnetic poles, which are arranged circumferentially to surround the rotor shaft 113. The magnetic poles are controlled by the control device 200 to rotate the rotor shaft 113 through an electromagnetic force acting between the rotor shaft 113 and the magnetic poles.
The motor 121 also has an RPM sensor (not shown in the drawing) incorporated to output a detection signal, which is used for detection of RPM of the rotor shaft 113.
A phase sensor (not shown in the drawing) is attached, for example, in the vicinity of the lower radial sensor 108 to detect the phase of rotation of the rotor shaft 113. From detection signals of the phase sensor and the RPM sensor both, the control device 200 detects positions of the magnetic poles.
A plurality of stationary blades 123a, 123b, 123c, . . . are arranged so as to be spaced apart from the rotor blades 102a, 102b, 102c, . . . by small gaps. To downwardly transfer the molecules of exhaust gas through collision, the rotor blades 102a, 102b, 102c, . . . are inclined by a predetermined angle with respect to a plane perpendicular to the axis of the rotor shaft 113.
Similarly, the stationary blades 123 are also inclined by a predetermined angle with respect to a plane perpendicular to the axis of the rotor shaft 113, and extend toward the inner side of the outer cylinder 127 to be arranged alternately with the rotor blades 102.
The stationary blades 123 are supported at one end by being inserted into gaps between a plurality of stationary blade spacers 125a, 125b, 125c, . . . stacked together in stages.
The stationary blade spacers 125 are ring-shaped members, which are formed of a metal, such as aluminum, iron, stainless steel, or copper, or an alloy containing such metal as a component.
In the outer periphery of the stationary blade spacers 125, the outer cylinder 127 is secured in position with a small gap therebetween. At the bottom of the outer cylinder 127, there is arranged a base portion 129, and a threaded spacer 131 is arranged between the lowermost one of the stationary blade spacers 125 and the base portion 129. In the portion of the base portion 129 below the threaded spacer 131, there is formed a discharge outlet 133 which communicates with the outside.
The threaded spacer 131 is a cylindrical member formed of a metal, such as aluminum, copper, stainless steel, or iron, or an alloy containing such metal as a component, and has a plurality of spiral thread grooves 131a in its inner peripheral surface.
The spiral direction of the thread grooves 131a is determined such that when the molecules of the exhaust gas move in the rotating direction of the rotor 103, these molecules are transferred toward the discharge outlet 133.
Connected to the lowermost one of the rotor blades 102a, 102b, 102c, . . . of the rotor 103 is a rotor blade 102d, which extends vertically downwards. The outer peripheral surface of the rotor blade 102d sticks out toward the inner peripheral surface of the threaded spacer 131 in a cylindrical shape, and is in close proximity to the inner peripheral surface of the threaded spacer 131 with a predetermined gap therebetween.
The base portion 129 is a disc-like member constituting the base of the turbo molecular pump main body 100, and is generally formed of a metal, such as iron, aluminum, or stainless steel.
The base portion 129 physically retains the turbo molecular pump main body 100, and also functions as a heat conduction passage. Thus, the base portion 129 is preferably formed of a metal that is rigid and of high heat conductivity, such as iron, aluminum, or copper.
In the above-described construction, when the rotor blades 102 are driven and rotated by the motor 121 together with the rotor shaft 113, an exhaust gas from a chamber is sucked in through the intake hole 101 by the action of the rotor blades 102 and the stationary blades 123.
The exhaust gas sucked in through the intake hole 101 passes between the rotor blades 102 and the stationary blades 123, and is transferred to the base portion 129. At this point, the temperature of the rotor blades 102 is raised by frictional heat generated as the exhaust gas comes into contact with the rotor blades 102 and by heat generated and conducted from the motor 121. Such heat is transferred to the stationary blades 123 through radiation or through conduction of gas molecules of exhaust gas or the like.
The stationary blade spacers 125 are joined to one another on the outer periphery and send, to the outside, heat which the stationary blades 123 receive from the rotor blades 102 as well as frictional heat generated upon contact between exhaust gas and the stationary blades 123.
The exhaust gas transferred to the base portion 129 is sent to the discharge outlet 133 while being guided by the thread grooves 131a of the threaded spacer 131.
In the description above, the threaded spacer 131 is placed on the outer periphery of the rotor blade 102d and the inner peripheral surface of the threaded spacer 131 is scored with the thread grooves 131a. This may be reversed and the outer peripheral surface of the rotor blade 102d may be scored with thread grooves, whereas a spacer of which inner peripheral surface forms a cylindrical shape surrounds the rotor blade 102d.
Further, in order to prevent the exhaust gas sucked in through the intake hole 101 from entering the electrical portion composed of the motor 121, the lower radial electromagnet 105, the lower radial sensor 108, the upper radial electromagnet 104, the upper radial sensor 107, etc., the electrical portion is covered with a stator column 122, and the interior of this electrical portion is maintained at a predetermined pressure with a purge gas.
For this purpose, the base portion 129 is equipped with piping (not shown in the drawing), and the purge gas is introduced through the piping. The purge gas introduced is passed through the gap between a protective bearing 120 and the rotor shaft 113, the gap between the rotor and stator of the motor 121, and the gap between the stator column 122 and the rotor blades 102 before it is transmitted to the discharge outlet 133.
The turbo molecular pump main body 100 requires control based on individually adjusted specific parameters (e.g., identification of the model and characteristics corresponding to the model). To store the control parameters, the turbo molecular pump main body 100 contains an electronic circuit portion 141 in its main body. The electronic circuit portion 141 is composed of a semiconductor memory, such as EEP-ROM, electronic parts, such as semiconductor devices for access to the semiconductor memory, a substrate 143 for mounting these components thereto, etc.
This electronic circuit portion 141 is accommodated under an RPM sensor (not shown in the drawing) near the center of the base portion 129 constituting the lower portion of the turbo molecular pump main body 100, and is closed by a hermetic bottom cover 145.
In some cases, a process gas is introduced to a chamber with its temperature raised in order to enhance the reactivity. Such process gas is cooled upon discharge and, reaching a certain temperature, could change into a solid to precipitate in the exhaust system. This type of process gas, one that becomes solid when cooled, adheres to the interior of the turbo molecular pump main body 100 and builds up.
For instance, a vapor pressure curve shows that SiCl4 used as a process gas for an Al etching device precipitates at low vacuum (760 torr to 10−2 torr) and low temperature (about 20° C.) to produce a solid product (e.g., AlCl3), which adheres and builds up in the turbo molecular pump main body 100. As the precipitate of the process gas builds up in the turbo molecular pump main body 100, the pump flow path is clogged with the deposit, thereby lowering the performance of the turbo molecular pump main body 100. The solid product tends to coagulate and adhere in the area near the discharge outlet where the temperature is low, in particular, around the rotor blades 102 and the threaded spacer 131.
A conventional measure taken to solve this problem is to wind a heater (not shown in the drawing) and a ring-like water-cooled tube 149 around the outer periphery of the base portion 129 or other portion while burying a temperature sensor (not shown in the drawing) (e.g., thermistor) in, for example, the base portion 129, so that the temperature of the base portion 129 is kept high at a set temperature by controlling the heating effect of the heater and the cooling effect of the water-cooled tube 149 based on a signal from the temperature sensor (temperature management system, hereinafter abbreviated as TMS).
Given next is a detailed description of the magnet bearing control circuit 201 for exciting and controlling the upper radial electromagnets 104, the lower radial electromagnets 105, and the axial electromagnets 106A and 106B of the turbo molecular pump main body 100 and the control device 200 structured as above.
A structural diagram of the magnetic bearing control circuit and a control circuit is shown in FIG. 15.
In FIG. 15, the control device 200 has the magnetic bearing control circuit 201 provided for the respective electromagnets including the upper radial electromagnets 104 and the lower radial electromagnets 105. Accordingly, in the case of a 5-axis control magnetic bearing, there are ten of the same magnetic bearing control circuits (each of which is denoted by 201 and only some of them are shown in the drawing) in the control device 200.
The magnetic bearing control circuit 201 has a PID control circuit 203 to which a displacement signal sent from the upper radial sensor 107 or other sensors is inputted. The PID control circuit 203 performs PID control on the displacement signal inputted, and outputs as a current command signal a current value necessary to drive the upper radial electromagnets 104 (the current value is hereinafter referred to as current command value) to a current error computing unit 205.
The current error computing unit 205 calculates an error between the current command signal outputted from the PID control circuit 203 and an electromagnet current detection signal outputted from an amplifier circuit 210, (the error is hereinafter referred to as current error value) which will be described later. The current error computing unit 205 then outputs the obtained current error value as a current error signal to a pulse control circuit 207.
The pulse control circuit 207, along with the amplifier circuit 210, will be described next.
A circuit diagram of the amplifier circuit is shown in FIG. 16.
In FIG. 16, the electromagnet coil 151, which constitutes the upper radial electromagnets 104 or other electromagnets, is connected at one end to a positive electrode 221a of a power source 221 through a transistor 211 and is connected at the other end to a negative electrode 221b of the power source 221 through an electromagnetic current detecting circuit 231 and through a transistor 212.
The transistors 211 and 212 are so-called N type power MOSFETs. The transistor 211 has at one end a drain terminal 211a connected to the positive electrode 221a and has at the other end a source terminal 211b connected to the one end of the electromagnet coil 151. The transistor 212 has at one end a drain terminal 212a connected to the electromagnet current detecting circuit 231 and has at the other end a source terminal 212b connected to the negative electrode 221b.
On the other hand, a diode 215 provided for current regeneration has a cathode terminal 215a connected to one end of the electromagnet coil 151 and has an anode terminal 215b connected to the negative electrode 221b. Similarly, a diode 216 for current regeneration has a cathode terminal 216a connected to the positive electrode 221a and has an anode terminal 216b connected to the other end of the electromagnet coil 151 through the electromagnetic current detecting circuit 231.
The electromagnet current detecting circuit 231 is, for example, a hole sensor serving as a current sensor, and detects the amount of a current flowing in the electromagnet coil 151 (hereinafter referred to as electromagnet current iL) to output the detected current value as an electromagnet current detection signal to the current error computing unit 205.
Also provided between the positive electrode 221a and negative electrode 221b of the power source 221 is a stabilizing capacitor 223 for stabilizing the power source 221.
A node P, which designates the section between the one end of the electromagnet coil 151 and the transistor 211, and a node Q, which designates the section between the other end of the electromagnet coil 151 and the electromagnet current detecting circuit 231, constitute a cable 170 for connecting the control device 200 to the turbo molecular pump main body 100 as shown in FIG. 15, which is because the electromagnet coil 151 is an element of the turbo molecular pump main body 100.
As the magnetic bearing controlling circuit 201 is provided for the respective electromagnets including the upper radial electromagnets 104 and the lower radial electromagnets 105, the amplifier circuit 210 structured as above is provided for each of those electromagnets, meaning that there are identical amplifier circuits (each of which is denoted by 210) for the lower radial electromagnets 105 and for the axial electromagnets 106A and 106B in addition to the amplifier circuit 210 for the upper radial electromagnets 104.
The pulse control circuit 207 determines the pulse width (pulse width time Tp1, Tp2) of pulses to be generated within a control cycle Ts, which is one cycle by PWM control, based on a current error signal outputted from the current error computing unit 205 in order to increase or decrease the electromagnet current iL. At this point, the pulse control circuit 207 receives a carrier wave having a given cycle (for example, 25 kHz) and the control cycle Ts is determined in accordance with the cycle of the carrier wave. The pulse control circuit 207 thus outputs a signal having the pulse width time Tp1 or Tp2 (hereinafter referred to as gate drive signal) within the control cycle Ts to gate terminals of the transistors 211 and 212, to thereby switch on or off the transistors 211 and 212.
In this structure, when a current command value outputted from the PID control circuit 203 is larger than a current detection value detected at the electromagnet current detecting circuit 231, in other words, when the electromagnet current iL is to be increased, the transistors 211 and 212 are both kept turned on for a time period corresponding to the pulse width time Tp1 within the control cycle Ts and are both kept turned off during a time period corresponding to the pulse width time Tp2 (=Ts−Tp1) as shown in FIG. 17.
While the transistors 211 and 212 are both kept turned on, the electromagnet current iL flowing from the positive electrode 221a to the negative electrode 221b through the transistor 211, the electromagnet coil 151, and the transistor 212 is supplied to the electromagnet coil 151 (the electromagnet current iL is increased during this period). On the other hand, while the transistors 211 and 212 are both kept turned off, the electromagnet current iL regenerated from the negative electrode 221b to the positive electrode 221a through the diode 215, the electromagnet coil 151, and the diode 216 is supplied to the electromagnet coil 151 (the electromagnet current iL during this period is smaller than when the transistors 211 and 212 are both turned on).
Therefore, the electromagnet current iL within one control cycle Ts is (ultimately) increased by setting the pulse width time Tp1 longer than the pulse width time Tp2.
This is all reversed in the case where a current command value outputted from the PID control circuit 203 is smaller than a current detection value detected at the electromagnet current detecting circuit 231, in other words, when the electromagnet current iL is to be decreased. The electromagnet current iL within one control cycle Ts is decreased by setting the pulse width time Tp2 longer than the pulse width time Tp1.
By turning one of the transistors 211 and 212 of the amplifier circuit 210 on, a flywheel current is maintained in the amplifier circuit 210 (not shown in the drawing) as disclosed in JP 3176584 B.
Maintaining a flywheel current in the amplifier circuit 210 makes it possible to reduce the hysteresis loss in the amplifier circuit 210 and lower the total current consumption of the circuit. In addition, with the transistors 211 and 212 controlled in this manner, high-frequency noise of harmonics or the like is reduced in the turbo molecular pump main body 100.
As has already been described, the magnetic bearing control circuit 201 is provided for the respective electromagnets including the upper radial electromagnets 104 and the lower radial electromagnets 105 and accordingly the control device 200 has ten identical amplifier circuits (each denoted by 210). Taking into account this and the fact that, in each amplifier circuit 210, two transistors 211 and 212 and two diodes 215 and 216 are necessary for every electromagnet coil 151, the control device 200 needs twenty transistors and twenty diodes in total to drive, through excitation, every electromagnet.
Meanwhile, the transistors 211 and 212 and the diodes 215 and 216 have to be large in element size (channel width for the transistors and junction area for the diodes) in order to supply a large current to the electromagnet coil 151.
It is therefore difficult to downsize the amplifier circuit 210 while ensuring enough current supply to the electromagnet coil 151 and, as a result, reducing the control device 200 in size is made difficult.
The control device 200 therefore takes up much space when installing the turbo molecular pump main body 100 and the control device 200 in a clean room or the like, and it could lead to an increase in cost for the installation.
In addition, as described above, the nodes P and Q that connect the amplifier circuit 210 and the electromagnet coil 151 to each other constitute the cable 170 laid between the control device 200 and the turbo molecular pump main body 100 for interconnection. With the control device 200 having ten amplifier circuits (210), there are twenty wires in total as the nodes P and Q in the cable 170.
Consequently, the cable 170 cannot be reduced in number of wires, thereby making it difficult to lower the cost of the cable 170.
Furthermore, the wires serving as the nodes P and Q have to be large in diameter in order to send a large current to the electromagnet coil 151.
This makes it difficult to reduce the cable 170 in diameter and, accordingly, downsizing of a connector (not shown in the drawing) serving as an entrance and an exit of the turbo molecular pump main body 100 for the cable 170 is also made difficult. The connector on the side of the turbo molecular pump main body 100 bears a special task to enable the cable 170 to serve as an input/output cable while maintaining the vacuum state in the turbo molecular pump main body 100. Therefore, a difficulty in reducing the diameter of the connector could directly lead to a rise in total manufacture cost of the turbo molecular pump.

Magnetic bearing device and turbo molecular pump with the magnetic bearing device mounted thereto