The present invention provides solutions of certain 4,4'-bipyridinium salts, such as salts of 1,1'- dibenzyl-2,2',6,6'-tetraalkyl-4,4'-bipyridinium cations. The solutions of the invention are employed as solutions of variable transmittance in solution-phase electrochromic devices, including such devices that are single-compartment and self-erasing. In the solutions of the invention in such devices, the bipyridinium salts are cathodic electrochromic compounds, as reduction of a cation of such a salt causes its molar extinction coefficient at at least one wavelength in the visible range to increase markedly. Electrochromic devices, in which solutions of the invention provide variable transmittance, are, in turn, components of variable transmittance in display devices, windows and other types of light filters, and variable reflectance mirrors, such as those that can be used as dimmable rearview mirrors in motor vehicles.

In electrochromic devices, the color or darkness of a composition is changed by an electrochemical reaction caused by application of an electrical potential difference to electrodes in contact with the composition. Electrochromic devices long have been of interest for providing varying displays in display devices of various types, varying transmittance in variable transmittance lights filters, such as windows, and varying reflectance in variable reflectance mirrors.
In a solution-phase electrochromic device, at least one substance, which changes color or absorbance to light in the visible wavelength range in an electrochemical reaction in operation of the device, is in a solution in the device both at equilibrium with no potential applied to cause an electrochemical reaction and when reduced (if the substance is "cathodic," i.e., electrochemically reduced in the device) or oxidized (if the substance is "anodic," i.e., electrochemically oxidized in the device).
One type of solution phase electrochromic device is a single-compartment, solution-phase, self-erasing electrochromic device. U.S. Pat. No. 4,902,108 (hereinafter the U.S. Pat. No. '108), the entire disclosure of which is incorporated herein by reference, describes a class of such solution-phase electrochromic devices. The U.S. Pat. No. '108 also describes solutions for use as the media of reversibly variable transmittance in such devices; "cathodic" compounds, which undergo a color change on electrochemical reduction in such devices; and "anodic" compounds, which undergo a color change on electrochemical oxidation in such devices. In the devices of the U.S. Pat. No. '108, the reduced cathodic compound and oxidized anodic compound remain in solution and react with each other to regenerate the zero-potential equilibrium forms of both compounds. Further, the U.S. Pat. No. '108 describes the use of the electrochromic devices of the Patent as the components of varying color or darkness in various display devices; the components of reversibly variable transmittance in light filters, such as windows; and the components of reversibly variable transmittance in variable reflectance mirrors, such as dimmable, rearview mirrors for motor vehicles.
In a single-compartment, self-erasing, solution-phase electrochromic device, such as those of the U.S. Pat. No. '108, a solution comprising a cathodic compound and an anodic compound is held in contact with two electrodes. Preferably the solution is held as a layer of solution between and in contact with two, substantially planar, parallel, spaced-apart electrode layers. These electrode layers may be substantially transparent layers (such as of indium-tin oxide or fluorine-doped tin oxide) coated on a substantially transparent material, such as glass. With no potential difference between the electrode layers, and the solution therebetween in its zero-potential equilibrium state, the solution can be clear or slightly colored. When a potential difference of sufficient magnitude (which will typically be less than about 2.0 volts and will depend on a number of factors, including the reduction potentials of the cathodic and anodic compounds in the solution) is applied to the electrode layers (and across the solution therebetween), transmittance of light through the device is reduced, and the color of the device may be perceived as changing, as reduction of cathodic compound at the electrode functioning as the cathode yields a composition with a molar extinction coefficient at at least one wavelength in the visible range that is higher than that of the cathodic compound in its zero-potential equilibrium state and, similarly, oxidation of anodic compound at the electrode functioning as the anode yields a composition with a molar extinction coefficient at at least one wavelength in the visible range that is higher than that of the anodic compound in its zero-potential equilibrium state. The rate at which the solution layer darkens or changes color once a potential difference is applied to the electrode layers, and the steady-state darkness or color that results if a potential difference is maintained for a sufficiently long period of time, will depend on a number of factors, including the potential difference, the current across the solution layer, the thickness of the solution layer, and the rate at which reduced cathodic compound is re-oxidized and oxidized anodic compound is re-reduced (e.g., in the case of cathodic compound, by reaction of the reduced cathodic compound with oxided anodic compound in the solution). Once the potential difference between the electrode layers is reduced or eliminated, the color or darkness of the solution layer will return toward its zero-potential equilibrium state, as the concentrations of reduced cathodic compound and oxidized anodic compound will decrease toward lower, steady-state levels. Thus, by adjusting the potential difference between the electrode layers, such a device can function as a "gray-scale" device, with continuous, or step-wise, variable transmittance over a wide range. Ideally, when the potential between the electrodes of such a device is returned to zero, the device spontaneously returns to the same, zero-potential, equilibrium color and transmittance as the device had before the potential was applied.
Approaching this ideal sufficiently closely to make the use of single-compartment, solution-phase, self-erasing electrochromic devices commercially feasible has been a problem. Thus, in most applications of such devices, the cycle-life of the devices (the number of times the potential between the electrodes can be applied and removed without unacceptable degradation in the device, e.g., in the color or darkness of the device in the zero-potential, equilibrium state or the steady state at a selected potential difference) is an important factor and presents a formidable problem. In practical applications, the anodic and cathodic compounds in a solution must be stable to many thousands of cycles of oxidation and reduction.
In applications of single-compartment, solution-phase, self-erasing electrochromic devices in mirrors and windows, a significant problem is stability of the components of the solutions of reversibly variable transmittance in the devices to violet and ultraviolet (UV) light. Thus, when the device is activated (i.e, a potential is placed across the solution of the device sufficient to cause coloration), the performance of the device is typically degraded on exposure of the solution to violet and ultraviolet light. The degraded performance manifests itself as residual color formation in the device, which does not clear up when the device returns to its zero-potential, equilibrium state, and as a decrease in the darkness of coloration attainable with the device when it is activated. Thus high-end (at low or no potential difference) transmission or reflectance of a window or mirror, respectively, is undesirably decreased and the low-end (at significant potential difference with substantially reduced transmittance) transmission or reflectance that can be achieved is undesirably increased.
Under most modes of operation, dimmable rearview mirrors for motor vehicles, which use solution-phase electrochromic devices to provide variable reflectance and their dimming effect, are only colored or dimmed (darkened) at night when light from the headlamps of following vehicles can pose a glare problem for drivers. At night the amount of violet or ultraviolet radiation reaching the solution of the device is insufficient to cause significant degradation over the expected life of the rearview mirror device. However, even in the zero-potential, equilibrium state, solution-phase devices, such as those of the U.S. Pat. No. '108, are slowly degraded by exposure of the solution of the devices to ultraviolet light. This slow degradation process is of particular concern with outside rearview mirrors on motor vehicles since they may be exposed to sunlight containing ultraviolet light day after day over a number of years. In fact, in electrochromic devices which are variable transmittance components of outside, dimmable, rearview motor vehicle mirrors and contain electrochromic solutions according to the U.S. Pat. No. '108 as media of variable transmittance, the electrochromic solutions do degrade over a period of several months to a year to the point where they become unacceptable for outside dimmable rearview mirror use.
Attempts to solve the problem of instability to exposure to ultraviolet ("UV") light have included the use of screens or barriers to UV light, to intercept UV-light before it reaches the solution of the electrochromic device, or the inclusion, in the solution of reversibly variable transmittance in the device, of UV-stabilizing compounds. The UV-stabilizing compounds that have been used have been developed to stabilize organic compositions (e.g., plastics) against degradation by exposure to UV light. The use of screens or barriers of UV-light-absorbing material adds significantly to the cost of materials for electrochromic devices and significantly complicates the manufacture of such devices by requiring that the screen or barrier be incorporated into the device while avoiding undesirable optical effects that may accompany such incorporation. The use of UV-stabilizing compounds in solutions of reversibly variable transmittance in electrochromic devices, while in many cases capable of increasing the useful life of the devices by retarding photodegradation in the solutions exposed to UV light while in their zero-potential equilibrium state, are not totally effective in eliminating this UV-induced photochemical degradation. Further, the degradative products that do form in the solutions when UV-stabilizing compounds are present significantly reduce the useful cycle life of the devices when they are cycled between the clear and colored state, even, e.g., at night, in the absence of light which might cause additional photochemical degradation during cycling. Thus, a problem confronting the art of solution-phase electrochromic devices, including single-compartment, solution-phase, self-erasing electrochromic devices, is to identify compounds which are suitable for use as anodic or cathodic compounds in the solutions of reversibly variable transmittance in such devices and that render such solutions, at least in their zero-potential equilibrium states, highly stable to exposure to ultraviolet light from e.g. sunlight.
There are a number of other desireable characteristics in anodic or cathodic compounds for use in solutions of variable transmittance in solution-phase electrochromic devices, including those which are single-compartment and self-erasing. Such compounds are desirably stable in solution by themselves and in combination with each other in their zero-potential equilibrium states even at high temperatures above about 80.degree. C. and preferably up to about 120.degree. C. The anodic and cathodic compounds in their colored or activated states in solution should be stable at at least 50.degree. C. and preferably at at least 75.degree. C., so that devices containing solutions of the compounds can be cycled without significant degradation between their colorless and colored states at at least 50.degree. C. and preferably at at least 75.degree. C. Anodic and cathodic compounds for media of variable transmittance in electrochromic devices which need to operate over a large range in transmittance or reflectance, as in high quality, dimmable rearview mirrors for motor vehicles, should be colorless or nearly colorless in their zero-potential equilibrium state, undergo a large increase in molar extinction coefficient in the visible range on oxidation or reduction, and be soluble enough to provide for the range of transmittance or reflectance required in the device in which a solution of the compound is employed to provide variable transmittance.
A particularly preferred solution for use as the medium of reversibly variable transmittance in a single-compartment, solution-phase, self-erasing electrochromic device, used to provide variable reflectance in a variable reflectance rearview mirror for a motor vehicle, consists of propylene carbonate as solvent, benzylviologen difluoroborate (i.e., 1,1'-dibenzyl-4,4'-bipyridinium difluoroborate) as cathodic compound at 5 mM -50 mM in the solution at room temperature, 5,10-dihydro-5,10-dimethyl phenazine as anodic compound at 5 mM -50 mM in the solution at room temperature, 1-10% (w/w) polymethylmethacrylate to thicken the solution, and ethyl 2-cyano-3,3-diphenyl acrylate at 200 mM to 700 mM in the solution at room temperature to somewhat retard UV-associated photodegradation in the solution in its zero-potential equilibrium state. This system of compounds fits the stability, color and solubility criteria discussed above. However, for long lived outside rearview mirrors, especially outside rearview mirrors on automobiles, and certain window applications, very high stability against long term exposure to sunlight is required while the device is colorless or unactivated. A problem remains with the above system of compounds: slow degradation in sunlight, with the degradation products that form adversely affecting the cycle life of the devices containing the systems of compounds.
Salts of 4,4'-bipyridinium dications, in addition to the well known viologen salts, derivatized at the 1 and 1' positions are known. See Emmert and Varenkamp, Chemishe Berichte 56B, 491-501 (1923); and Sugiyama et al., Japanese Patent Application Publication No. 61-148,162 (1986). There have been no reports suggesting the use, or the advantages of using, salts of 4,4'-bipyridinium dications derivatized at 1 or 1' position with alkyl, phenyl or benzyl, and at at least one of the 2,2',6 and 6' positions with alkyl as cathodic compounds in solutions of reversibly variable transmittance in solution-phase electrochromic devices.


A parking assist apparatus includes an initial traveling locus calculator for calculating an initial traveling locus, a new traveling locus calculating a new traveling locus when a deviation amount of the present vehicle position from a current traveling locus is equal to or greater than a first predetermined value, and a parking assist for performing a parking assist to guide the vehicle along the traveling locus. The parking assist apparatus further includes an initial traveling locus deviation calculator for calculating the deviation amount of the present vehicle position from the initial traveling locus generated by the calculation of the initial traveling locus calculator. The parking assist stops performing the parking assist when the deviation amount calculated by the initial traveling locus deviation calculator is equal to or greater than a second predetermined value which is smaller than the fist predetermined value.

A known parking assist apparatus calculates a traveling locus of a vehicle to a target parking position and guides the vehicle along the calculated traveling locus. Such a parking assist apparatus is disclosed in Japanese Patent Laid-Open Publication No. H10-264839. According to the disclosed parking assist apparatus, a deviation amount of a present vehicle position from the calculated traveling locus is calculated while the vehicle is guided to the target parking position. When the deviation amount reaches or exceeds a predetermined value, the traveling locus to the target parking position is recalculated to thereby specify a new traveling locus required for a movement of the vehicle. Therefore, the vehicle may be guided along a newly calculated traveling locus each time the vehicle is deviated from the traveling locus to the target parking position according to the disclosed parking assist apparatus.
According to the disclosed parking apparatus, the vehicle is appropriately guided to the target parking position by calculating the new traveling locus in case that the vehicle is slightly deviated from the initially calculated traveling locus due to a small obstacle such as an inclination of a road and a stone, a disturbance such as a change of a wheel radius caused by a change of a load mounted on the vehicle, and the like. However, if an error of a system itself of the parking assist apparatus occurs, the vehicle cannot be ultimately guided to the target parking position even though the new traveling locus is calculated. As a result, the vehicle cannot be parked in the target parking position.
When the new traveling locus is repeatedly calculated each time the deviation of the present vehicle position from the initially calculated traveling locus is detected to thereby guide the vehicle to the target parking position, the vehicle may move in an unexpected manner due to the continuation of the parking assist control.
Thus, a need exists for a parking assist apparatus that can stop a parking assist control immediately when a system error occurs.


A method for the storage or transportation of an erythritol by maintaining erythritol in the form of a solution at a concentration and at a temperature in given ranges. Setting up such conditions enables long-term storage of an erythritol solution or transportation of erythritol to the destination in a state of a solution.

The present invention relates to a method for the storage or transportation of an erythritol solution. More particularly, the present invention relates to a method for the storage or transportation of erythritol as food not in the form of crystal powder but of a solution with preventing contamination and deposition of crystals.
Erythritol is a sugar alcohol having 4 carbon atoms and is used widely in food industry as a sweetener having various characteristics such as a degree of sweetness of about 70% of that of sucrose, low energy property, and non-cariogenic property.
Conventionally, the storage (preservation) and transportation (distribution) of erythritol is practiced in a state where usually 20 kg of dry crystal powder as a unit is filled in a paper bag.
In recent years, erythritol has been put in use by beverage manufacturers and the demand therefor has been expanded remarkably. After purchase of erythritol, the beverage manufacturers as mass consumers open a large number of 20-kg bags one by one and throw the crystal into a solution tank to dissolve it before use. However, according as the consumption amount increases, there have arisen undesirable problems from the viewpoints of not only operation but also energy consumption and environmental protection. For example, labor and time required for opening the bags become overmuch. And since erythritol remarkably absorbs heat when it is dissolved, it is hard to dissolve, so that generally it is necessary to dissolve erythritol by stirring and heating with a considerable amount of dissolution energy (concretely with steam) with a use of a solution tank with a stirrer mounted. Furthermore, a considerable numbers of empty bags are treated as wastes.
The present inventors have made various studies in pursuit of erythritol product that is free of the above-mentioned defects. As a result they have found out that various problems on the storage, transportation or the like as described above can be overcome by maintaining erythritol in the form of a solution under given conditions. The present invention is based on this finding.
That is, the present inventors have made a study on the method for supplying erythritol to consumers by converting erythritol to a solution in a stage of shipment and storing or transporting it in the form of solution with studying conditions where no microorganism grow and the product will not deteriorate by coloring with heat or the like, more specifically storage temperature and erythritol concentration.
More specifically, they have studied on the conditions of storage temperature and concentration under which no microorganism will grow, conditions of storage temperature and concentration under which no erythritol crystal will precipitate and conditions of storage temperature under which no coloring of solution will proceed and studied the parameters that satisfy these three conditions.
As a result, they have found out parameters that satisfy them and created a method for the storage or transportation of erythritol in the form of a solution.
The present invention relates to a method for the storage or transportation of an erythritol solution comprising maintaining an erythritol solution under conditions of a solid content of 30% or more and a temperature of 50xc2x0 C. or more, preferably a solid content of 50 to 70% and a temperature of 50 to 75xc2x0 C., and more preferably a solid content of 50 to 58% and a temperature of 55 to 65xc2x0 C., such that no erythritol crystal precipitates.
Erythritol is produced by fermentation of glucose as a raw material using a microorganism having an erythritol producing ability. Erythritol in the fermentation liquid is then subjected to a purification process, more specifically the steps of cell separation, chromatographic separation, ion exchange resin treatment, activated carbon treatment, crystallization, crystal separation, and drying to produce a product of a crystal powder.
It is preferable that in the above process, the erythritol solution of the present invention is produced by concentrating the liquid being subjected to an activated carbon treatment before crystallization to a predetermined concentration, that is, a solid content of 30% or more, desirably from 50 to 70%, and more desirably from 50 to 58%.
The erythritol solution of the present invention may also be produced by adding water to the crystals after crystal separation to dissolve them to a predetermined concentration.
In the present invention, the erythritol solution prepared so as to have a predetermined concentration is maintained at a temperature that does not cause crystal precipitation, can prevent the growth of microorganism and causes no deterioration of product due to coloring, i.e., about 50xc2x0 C. or more, usually from 50 to 75xc2x0 C., preferably from 55 to 65xc2x0 C.
The present invention is a method for the storage or transportation of an erythritol solution comprising maintaining the erythritol solution at a concentration and a temperature within given ranges. Setting up such conditions enables long-term storage of an erythritol solution and transportation of erythritol to the destination in the form of a solution.
The erythritol solution is poured in a tank, for example a tank trailer or a freight car, and is stored or transported to the destination by means of keeping warm if necessary so as to prevent the precipitation of crystal.

Method for storing or transporting erythritol solution


In a unit case of a vehicle air conditioning apparatus, air mix chamber is not provided. Cooled air cooled by an evaporator and heated air heated by a heater core are directly introduced to a face opening and a foot opening of the case and then mixed in a face duct and a foot duct. The case has a guide for directing a flow of the heated air or the cooled air. The guide, the foot opening and the face opening are arranged such that the amount of heated air passing through the foot opening is larger than that of the cooled air and the amount of cooled air passing through the face opening is larger than that of the heated air in a bi-level mode. Accordingly, a temperature of air blown from a foot outlet into a passenger compartment is different from that of air blown from a face outlet.

In a vehicle having a large rear space such as a minivan, it is proposed to perform air-conditioning operation for the rear space independently from a front space. An air conditioning apparatus for a vehicle rear space is for example disclosed in Japanese Unexamined Patent Document No. JP-A-10-109523.
In the air-conditioning apparatus, as shown in FIG. 9, a blower fan 901 is arranged in a blower case 909 in a form of scroll and is rotated by a blower motor 910, which is driven by a power from a vehicle-mounted battery. The blower fan 901 sucks an inside air inside of a passenger compartment through a suction port 908 and blows the air into a cooler case 914, which is provided at a position downstream of the blower case 909. In the cooler case 914, an evaporator 902 performs heat exchange between a refrigerant flowing therein and the air blown by the blower fan 901, thereby cooling the air. A heater case 915 is connected to a downstream position of the cooler case 914. In the heater case 915, a heater core 904 is provided on a side adjacent to the passenger compartment and an air mix door 903 is provided on a side adjacent to the outside of the vehicle. The heater core 904 performs heat exchange between an engine cooling water and the cooled air having passed through the evaporator 902, thereby heating the air. The air mix door 903 can be moved to an optional position (air mix mode) between a position (MAX HOT) where the air is entirely introduced toward the heater core 904 and a position (MAX COOL) where the air is entirely introduced toward a cooled air bypass passage.
Further, in the heater case 915, an air mix chamber 911 is formed at a position downstream of the bypass passage and the heater core 904. Thus, the heated air passed through the heater core 904 and the cooled air passed through the bypass passage merge with each other in the air mix chamber 911. The mixed air is distributed toward a roof opening 906 and a foot opening 907 by a mode door 905. The mode door 905 is selectively set to a roof air-blowing mode position, a foot air-blowing mode position, or a bi-level mode position. In the roof air-blowing mode, the air is entirely introduced toward the roof opening 906. In the foot air-blowing mode, the air is entirely introduced toward the foot opening 907. In the bi-level mode, the mode door 905 is set to an optional position between the roof air-blowing mode position and the foot air-blowing mode position so that the mixed air is divided toward the roof opening 906 and the foot opening 907 with a desired ratio. Here, the blower unit 909, the cooler case 914, and the heater case 915 are located in a space between a side trim 912 and an outer panel 913 that defines an outer wall of a body.
Because the space of the air mix chamber 911 is reduced to improve mountability of the air conditioning apparatus to the rear space of the vehicle, the heated air passed through the heater core 904 is forcibly directed toward the air mix chamber 911 by a guide 916. Therefore, it is likely to be difficult to maintain the volumes of air blown from the respective air-blowing outlets sufficiently. On the other hand, the space between the side trim 912 and the outer panel 913 is limited. Therefore, it is required to further improve the mountability of the vehicle rear seat air conditioning apparatus. Further, in the bi-level mode, it is required to control air temperature such that the air blown toward a passenger's foot area is hotter than the air blown toward a passenger's face area.


The invention relates to a magazine-related bus arrangement, wherein the magazine includes a backplane (1a) having electric contact fields and means for holding a number of circuit boards having edge-related electric contact surfaces in electric coaction with respective contact fields, adapted to enable the exchange of information-carrying signals between one or more first circuit arrays (102) belonging to a first circuit board (10), and one or more other circuit arrays (112) belonging to one or more second circuit boards (11). The logical number of bus-related conductors (m+n) with reserve conductors (n) slightly exceeds the numbers (m) necessarily required for a chosen signalling system and a non-error-tolerant signal exchange.

The construction of a signalling system and the creation of a signal exchange tolerant to occurrent errors in a circuit board or bus arrangement are known to the art in several different forms and constitute a basic requisite for the functioning of a complicated electronic system.
Errors in digital data systems are practically unavoidable and are due, at least partly, to the complexity of the circuits and circuit arrangements used and the complexity of associated electronic and electromechanical components.
By way of an example of the earlier standpoint of techniques in the present context, reference is made to International Patent Publication WO 94/03901 (International Patent Application PCT/US93/07262), which illustrates and describes in error-tolerant, high-speed bus system in an integrated circuit application (wafer scale integration). In this known construction, the bus arrangement includes a plurality of bus lines coordinated in a number of sections or segments and mutually linked via programmable bus couplers. The segments are mutually identical and each segment contains thirteen signal lines.
The International Patent Publication WO 94/14026 (international Patent Application PCT/US93/11343) teaches a data collecting system which utilizes a plurality of parallel data buses (A, B, C) connected to a central control unit (10) and each sensor (14, 15, 16) can be connected to the central control unit (10) over any one of the data buses, through an addressing procedure.
An error in one of the data busses (A, B, C) creates conditions under which the faulty data bus is blocked or by-passed, by using a faultless parallel data bus. The European patent application, Publication EP-A2-0 065 273 teaches a system for mutually coupling a plurality of data systems with the aid of a bus system which has information conductors and control conductors. This publication recommends that the requisite smallest number of control conductors shall be increased manifold, in order to obtain rapid notation of an error and a simple error tolerance.
European Patent Pulibcation EP-B1-0 077 153 teaches digital equipment and methods for achieving essentially continuous operation even when several error conditions occur.
This latter publication proposes that the bus structure within each processor module shall include duplicated bus structures, and that each functional unit may have a duplicated partner unit. When establishing an error, the process module is instrumental in isolating the bus or the unit that causes the error, by allowing information to be transferred to the other unit or module.
U.S. Pat. No. 4,412,281; 4,486,826; 4,453,251; 4,597,084; 4,750,177; and 5,247,522 also form part of the earlier standpoint of techniques.
With regard to magazine-related bus arrangements, to which technique the present invention refers, it is known from European Patent Publication EP-A2-0 302 351 to create conditions for building a number of complete bus arrangements in the backplane and to coordinate one or more of said bus arrangements with different circuit boards.
In this respect, it is necessary for the number of coordinated contact springs to correspond with the number of bus conductors in each coordinated group and for the number of bus conductors to be chosen to correspond to the least possible number of bus conductors so as to provide parallel signal transmission of the digital signals under non-redundant conditions.
The disclosures made in European Patent Publications EP-A1-0 488 057, EP-A2-0 301 499 and EP-A2-0 226 765 and the U.S. Pat. Nos. 5,006,961, 4,988,180 also belong to the earlier standpoint of techniques.
When summarizing the aforesaid known prior art, it can be said that it is known to create redundant bus arrangements in magazine-related bus arrangements of the kind to which the present invention relates, by using duplicated by triplicated complete bus arrangements or bus arrangements increased to an N-value, each exhibiting non-redundant and non-error-tolerant conditions.
Duplicated bus arrangements are chosen in those coupling arrangements with which it has been elected to substitute a utilized complete bus arrangement with a reserve complete bus arrangement when the first mentioned bus arrangement is afflicted with an error of a more or a less serious nature.
Triplicated bus arrangements have been used in applications where the requirements placed on reliability are extremely high and where is high error tolerance is required.


A method and associated systems for capturing configuration items from hybrid-cloud provisioning data. A processor of a service-management system intercepts a service request requesting that the hybrid cloud's orchestration mechanism provision or deprovision a configuration item of the hybrid cloud. The service-management system identifies the configuration item by examining the service request and then forwards the request to the cloud-orchestration mechanism. After confirming that the request has been satisfied, the service-management system retrieves from the orchestration mechanism provisioning information that describes attributes of the newly provisioned or deprovisioned configuration item and uses this information to update a configuration-management database, marking any provisioning information newly stored in the database as being authorized for use by other management systems of the hybrid cloud. The service-management system then enhances the stored data by means of an artificially intelligent analytics module and additional configuration-item data collected by a discovery agent.

The present invention relates to provisioning virtual resources in a cloud-computing environment and, in particular, to capturing information describing configuration items (CIs) required in order to manage a hybrid cloud-computing environment.
A hybrid cloud is a type of computing infrastructure that includes one or more "private" cloud or non-cloud environments under control of a user, and at least one "public" cloud-computing environment managed by a third party, such as a commercial broker of cloud-based services. These public and private zones of a hybrid cloud are distinct entities, but are coupled closely enough to enable multiple deployment models.
For example, a hybrid cloud might include a set of virtualized PaaS (Platform as a Service) services provisioned on a public cloud. In this case, provisioning these PaaS services on a public cloud might make those services more readily available to applications residing in other zones of the hybrid cloud, such as a private cloud or a private non-cloud enterprise data center.
Managing hybrid-cloud resources can be complex, and this is especially true when a hybrid cloud comprises non-virtualized domains. In such cases, change-management or service-management tasks may be at least partly handled by a dedicated service-management system (or "SMS") that tracks, manages, and controls configuration items ("CIs"). As the term is used here, a CI may be any entity of the hybrid cloud that must be managed and controlled in order to deliver a service. These entities may, for example, be comprise virtual machines, applications, infrastructure components, specific instances of software objects, configuration settings, middleware, networks, or a service itself.
In some embodiments, each CI may be identified by a unique name and a set of specific attributes, allowing an SMS to manage the CI as a self-contained unit throughout its lifecycle. This CI information may be stored or modeled in a configuration-management database ("CMDB") that stores attribute data about each CI and about relationships between CIs. This attribute data may, for example, comprise a combination of software-configuration settings, hardware specifications, or application requirements. Stored relationships between CIs may, for example, comprise a dependency relationship that requires two types of virtual machine to be provisioned in a certain order, or a relationship between a software application and an infrastructure component on which the application is installed.
Existing service-management systems generally use an automated discovery agent (or agentless tool) to collect CI information from service-management end points, such as network-management systems, infrastructure components, or network nodes. This discovered CI information is then stored in a CMDB for ongoing reference.
Data collected in this way, however, is not automatically validated as being accurate and current enough to be used reliably for configuration-management, billing-management, event-management, or other purposes by authorized IT-management systems like an SMS or a change-management system. Therefore, stored CI data must be validated or "promoted" to an authorized status, often by consolidating the stored CI data with other change-management data. In some cases, only validated CI information stored in a configuration-management database may be used by an authorized user or management system.
Because discovery entails examining every configuration item of every network of a hybrid cloud, using a discovery mechanism to populate a CMDB can be time-consuming and resource-intensive. In addition, a discovery tool must be initialized with details of the managed cloud environment in order to access every CI, such as a model of each cloud's network topology or privacy and security constraints that may restrict access to certain CIs.
It can also be difficult for a discovery tool to ensure that it is accurately tracking current states of every CI if a cloud is known to frequently provision and deprovision virtual resources. In such cases, by the time a discovery agent has finished traversing a large network, some virtualized CIs may have been added, deleted, or reconfigured by a cloud-orchestration mechanism or other provisioning function, thus rendering at least part of the discovered information obsolete before it can be reported.
Furthermore, although discovery agents can discover CIs known to a particular user's cloud-computing environment, they may not be able to identify changes made by a cloud-service provider without the user's knowledge. This may make it impossible to consolidate certain CIs with change-management data used by the cloud provider. In such cases, CI data may be known to a cloud's cloud-orchestration mechanism because that data is needed to perform operations like provisioning virtualized resources. However, existing CI discovery agents generally have no way to access that information.
There is thus a need for a method of capturing CI data and populating a CMDB that does not require brute-force automated discovery and there is a particular need for a way to access and consolidate existing configuration-item provisioning information that may already be known to a cloud-orchestration mechanism.

This patent is subject to a terminal disclaimer.

Capturing a virtual configuration from cloud-provisioning data

International Business Machines Corporation


A method and an apparatus map image information of a target object onto an interface of the target object in magnetic resonance imaging (MRI). The method includes obtaining the image information of the target object in a predetermined direction from the outside of the target object to the inside of the target object, analyzing the obtained image information, extracting one piece of the obtained image information based on the analysis result, and allotting the extracted image information onto the interface of the target object.

1. Field of the Invention
The present disclosure relates to magnetic resonance imaging (MRI), and more particularly to a method and an apparatus for mapping image information of a target object onto an interface of the target object in magnetic resonance imaging (MRI).
2. Description of the Related Art
Magnetic resonance imaging (MRI) is a technology which involves positioning a target object in a space formed by a large magnet that generates a magnetic field, generating a radio frequency (RF) pulse to have protons included in the target object resonate, measuring differences in signals generated by tissues included in the target object, and reconstructing the measured differences through a computer to obtain an image of the target object.
The MRI has higher resolution and contrast than those of other imaging methods, for example, methods that use ultrasonic waves, and may provide a deep organ image and three-dimensional information in real time. In addition, in the MRI, the target object is not exposed to radiation. Therefore, the MRI is harmless to a human body and may obtain axial, sagittal, and coronal images without changing the position of the target object.

Method and apparatus for mapping image information of target object onto interface of the target object in magnetic resonance imaging

Industry-University Cooperation Foundation Hanyang University


A method includes: acquiring, based on status information, a failure risk of each of a plurality of devices including physical devices and virtual machines, each of the virtual machines being operated on any of the physical devices, the status information indicating the statuses of the plurality of devices; acquiring an influence range based on route information indicating a link in a range affected by a failure; acquiring a first influence risk based on a failure risk acquired for a first device, the first physical device being any of the physical devices; acquiring a second influence risk based on a failure risk of a second device, the second influence risk indicating a possibility of a target device being affected by a failure in another device; and determining the second physical devices as a destination candidate of the target device when the second influence risk is lower than the first influence risk.

A computer system in a data center or a cloud computing system has many devices mixed therein and has a complicated system configuration. The devices mentioned here include virtual devices. In a large-scale system, failures occur due to various causes such as physical device failure and resource shortage. In a system having a complicated configuration, when a failure occurs in one device, the influence of the failure affects peripheral related devices, which in turn may lead to chain reaction failures of the peripheral devices. When a failure occurs in some devices, the influence of the failure may be stopped from spreading by moving a virtual machine (VM) that is affected by the failure due to fail-over or the like, for example, to another physical machine.
As a technique for determining a possibility of being affected by a failure, for example, an influence range specification program has been proposed to enable determination of a difference in the possibility of being affected by the failure.
Examples of the related art include Japanese Laid-open Patent Publication No. 2018-205811.

System management method, non-transitory computer-readable storage medium for storing system management program, and system management device


The present invention is directed to a high speed spindle motor comprising a stator assembly including a stator having multiple conductors that create a plurality of magnetic fields when electrical current is conducted by the conductors and a body of a phase change material such as a thermoplastic substantially encapsulating the stator. A rotatable hub having a magnet connected thereto is in operable proximity to the stator. The high speed motor also includes a shaft, a bearing surrounding the shaft and one of the bearing or shaft being fixed to the stator assembly and the other of the bearing or shaft being fixed to the rotatable hub. Hard disc drives using the motor, and methods of developing and constructing the motor and hard disc drives are also disclosed.

The present invention relates generally to a high speed motor. It relates particularly to a spindle motor such as used in a hard disc drive, and to the construction and arrangement of the body of the spindle motor to align and retain the respective component parts of the motor, as well as stator assemblies used in the motors and hard disc drives using the motors, and methods of developing and manufacturing high speed motors.
Computers commonly use disc drives for memory storage purposes. Disc drives include a stack of one or more magnetic discs that rotate and are accessed using a head or read-write transducer. Typically, a high speed motor such as a spindle motor is used to rotate the discs.
An example of a conventional spindle motor 1 is shown in FIG. 1. The motor 1 includes a base 2 which is usually made from die cast aluminum, a stator 4, a shaft 6, bearings 7 and a disc support member 8, also referred to as a hub. A magnet 3 and flux return ring 5 are attached to the disc support member 8. The stator 4 is separated from the base 2 using an insulator (not shown) and attached to the base 2 using a glue. Distinct structures are formed in the base 2 and the disc support member 8 to accommodate the bearings 7. One end of the shaft 6 is inserted into the bearing 7 positioned in the base 2 and the other end of the shaft 6 is placed in the bearing 7 located in the hub 8. A separate electrical connector 9 may also be inserted into the base 2.
Each of these parts must be fixed at predefined tolerances with respect to one another. Accuracy in these tolerances can significantly enhance motor performance.
In operation, the disc stack is placed upon the hub. The stator windings are selectively energized and interact with the permanent magnet to cause a defined rotation of the hub. As hub 8 rotates, the head engages in reading or writing activities based upon instructions from the CPU in the computer.
Manufacturers of disc drives are constantly seeking to improve the speed with which data can be accessed. To an extent, this speed depends upon the speed of the spindle motor, as existing magneto-resistive head technology is capable of accessing data at a rate greater than the speed offered by the highest speed spindle motor currently in production. The speed of the spindle motor is dependent upon the dimensional consistency or tolerances between the various components of the motor. Greater dimensional consistency between components leads to a smaller gap between the stator 4 and the magnet 3, producing more force, which provides more torque and enables faster acceleration and higher rotational speeds. One drawback of conventional spindle motors is that a number of separate parts are required to fix motor components to one another. This can lead to stack up tolerances which reduce the overall dimensional consistency between the components. Stack up tolerances refers to the sum of the variation of all the tolerances of all the parts, as well as the overall tolerance that relates to the alignment of the parts relative to one another.
In an effort to enable increased motor speed, some hard disc manufacturers have turned to the use of hydrodynamic bearings. These hydrodynamic bearings, however, have different aspect ratios from conventional bearings. An example of a different aspect ratio may be found in a cylindrical hydrodynamic bearing in which the length of the bearing is greater than it""s diameter. This results in more susceptibility to problems induced by differing coefficients of thermal expansion than other metals used in existing spindle motors, making it difficult to maintain dimensional consistency over the operating temperature that the drive sees between the hydrodynamic bearings and other metal parts of the motor. Hydrodynamic bearings have less stiffness than conventional ball bearings so they are more susceptible to imprecise rotation when exposed to vibrations or shock.
An important characteristic of a hard drive is the amount of information that can be stored on a disc. One method to store more information on a disc is to place data tracks more closely together. Presently this spacing between portions of information is limited due to vibrations occurring during the operation of the motor. These vibrations can be caused when the stator windings are energized, which results in vibrations of a particular frequency. These vibrations also occur from harmonic oscillations in the hub and discs during rotation, caused primarily by non-uniform size media discs.
An important factor in motor design is the lowering of the operating temperature of the motor. Increased motor temperature affects the electrical efficiency of the motor and bearing life. As temperature increases, resistive loses in wire increase, thereby reducing total motor power. Furthermore, the Arhennius equation predicts that the failure rate of an electrical device is exponentially related to its operating temperature. The frictional heat generated by bearings increases with speed. Also, as bearings get hot they expand, and the bearing cages get stressed and may deflect, causing non-uniform rotation and the resultant further heat increase, non-uniform rotation requiring greater spacing in data tracks, and reduced bearing life. One drawback with existing motor designs is their limited effective dissipation of the heat, and difficulty in incorporating heat sinks to aid in heat dissipation. In addition, in current motors the operating temperatures generally increase as the size of the motor is decreased.
Manufacturers have established strict requirements on the outgassing of materials that are used inside a hard disc drive. These requirements are intended to reduce the emission of materials onto the magnetic media or heads during the operation of the drive. Of primary concern are glues used to attach components together, varnish used to insulate wire, and epoxy used to protect steel laminations from oxidation.
In addition to such outgassed materials, airborne particulate in a drive may lead to head damage. Also, airborne particulates in the disc drive could interfere with signal transfer between the read/write head and the media. To reduce the effects of potential airborne particulate, hard drives are manufactured to exacting clean room standards and air filters are installed inside of the drive to reduce the contamination levels during operation.
Heads used in disc drives are susceptible to damage from electrical shorts passing through a small air gap between the media and the head surface. In order to prevent such shorts, some hard drives use a plastic or rubber ring to isolate the spindle motor from the hard drive case. A drawback to this design is the requirement of an extra component.
Another example of a spindle motor is shown in U.S. Pat. No. 5,694,268 (Dunfield et al.) (incorporated herein by reference). Referring to FIGS. 7 and 8 of this patent, a stator 200 of the spindle motor is encapsulated with an overmold 209. The overmolded stator contains openings through which mounting pins 242 may be inserted for attaching the stator 200 to a base. U.S. Pat. No. 5,672,972 (Viskochil) (incorporated herein by reference) also discloses a spindle motor having an overmolded stator. One drawback with the overmold used in these patents is that it has a different coefficient of linear thermal expansion (xe2x80x9cCLTExe2x80x9d) than the corresponding metal parts to which it is attached. Another drawback with the overmold is that it is not very effective at dissipating heat. Further, the overmolds shown in these patents are not effective in dampening some vibrations generated by energizing the stator windings.
U.S. Pat. No. 5,806,169 (Trago) (incorporated herein by reference) discloses a method of fabricating an injection molded motor assembly. However, the motor disclosed in Trago is a step motor, not a high speed spindle motor, and would not be used in applications such as hard disc drives. Thus, a need exists for an improved high speed spindle motor, having properties that will be especially useful in a hard disc drive, overcoming the aforementioned problems.
A high speed motor has been invented which overcomes many of the foregoing problems. In addition, unique stator assemblies and other components of a high speed motor have been invented, as well as methods of manufacturing and developing motors and hard disc drives. In one aspect, the invention is a high speed spindle motor comprising: a stator assembly, including a stator having multiple conductors that create a plurality of magnetic fields when electrical current is conducted by the conductors; and a body of a phase change material substantially encapsulating the stator; a rotatable hub having a magnet connected thereto in operable proximity to the stator; a shaft; a bearing around the shaft; and one of the shaft or bearing being fixed to the stator assembly and the other of the shaft or bearing being fixed to the rotatable hub.
In another aspect the invention is a hard disc drive comprising: a) a base assembly comprising a body of phase change material substantially encapsulating a stator and supporting a shaft; b) a hub having a magnet connected thereto in operable proximity to the stator, the hub being rotatably supported by a bearing on said shaft; c) one or more discs supported on said hub; and d) a read/write head for accessing data and recording or reading data on the one or more discs.
The invention provides the foregoing and other features, and the advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention and do not limit the scope of the invention, which is defined by the appended claims and equivalents thereof.

Hard disc drive with base incorporating a spindle motor stator


An ophthalmic multifocal lens, and a method of manufacturing same, at least comprising focal points for near, intermediate and far vision. The lens comprises a light transmissive lens body providing a refractive focal point, and a periodic light transmissive diffraction grating, extending concentrically over at least part of a surface of the lens body and providing a set of diffractive focal points. The diffraction grating is designed to operate as an optical wave splitter, the refractive focal point providing the focal point for intermediate vision and the diffractive focal points providing the focal points for near and far vision. The diffraction grating has an optical transfer function comprising a continuous periodic phase profile function having an argument modulated as a function of the radial distance (r) to the optical axis of the lens body, thereby tuning the light distribution in the focal points.

Ophthalmology is the field of medicine directed to the anatomy, physiology and diseases of the human eye.
The anatomy of the human eye is rather complex. The main structures of the eye include the cornea, a spherical clear tissue at the outer front of the eye; the iris, which is the coloured part of the eye; the pupil, an adaptable aperture in the iris that regulates the amount of light received in the eye; the crystalline lens, a small clear disk inside the eye that focuses light rays onto the retina; the retina is a layer that forms the rear or backside of the eye and transforms sensed light into electrical impulses that travel through the optic nerve to the brain. The posterior chamber, i.e. the space between the retina and the lens, is filled with aqueous humour, and the anterior chamber, i.e. the space between the lens and the cornea, is filled with vitreous humour a clear, jelly-like substance.
The natural crystalline lens has a flexible, transparent, biconvex structure, and together with the cornea, operates to refract light to be focused on the retina. The lens is more flat on its anterior side than on its posterior side and its curvature is controlled by the ciliary muscles to which the lens connects by suspensory ligaments, called zonules. By changing the curvature of the lens, the focal distance of the eye is changed so as to focus on objects at various distances. To view an object at a short distance of the eye, the ciliary muscles contract, and the lens thickens, resulting in a rounder shape and thus high refractive power. Changing focus to an object at a greater distance requires the relaxation of the lens and thus increasing the focal distance. This process of changing curvature and adapting the focal distance of the eye to form a sharp image of an object at the retina is called accommodation.
In humans, the refractive power of the crystalline lens in its natural environment is approximately 18-20 dioptres, roughly one-third of the total optical power of the eye. The cornea provides the remaining 40 dioptres of the total optical power of the eye.
With the ageing of the eye, the opaqueness of the lens diminishes, called cataract. Some diseases like diabetes, trauma, but also some medications, and excessive UV light exposure may also cause cataract. Cataract is painless and results in a cloudy, blurry vision. Treatments for cataracts include surgery, by which the cloudy lens is removed and replaced with an artificial one, generally called an intraocular lens, IOL.
Another age related effect is called presbyopia, which is manifested by difficulty in reading small print or seeing nearby pictures clearly. Presbyopia generally is believed to be caused by a thickening and loss of flexibility of the natural lens inside the eye. Age-related changes also take place in the ciliary muscles surrounding the lens. With less elasticity it becomes harder to focus at objects close to the eye.
A variety of intraocular lenses are also employed for correcting other visual disorders, such as myopia or nearsightedness, when the eye is unable to see distant objects caused by the cornea having too much curvature, for example. The effect of myopia is that distant light rays focus at a point in front of the retina, rather than directly on its surface. Hyperopia or farsightedness, caused by an abnormally flat cornea, such that light rays entering the eye focus behind the retina, not allowing to focus on objects that are close, and astigmatism, which is another common cause of visual difficulty in which images are blurred due to an irregularly-shaped cornea.
In the majority of cases, intraocular lenses are implanted in a patient's eye during cataract surgery, to compensate for the loss of optical power of the removed lens. Modern IOL optics are designed to have a multifocal optic for providing short, intermediary and distance vision of objects, also called multifocal IOL, MIOL, or more specific trifocal lenses. Presbyopia is corrected by eye glasses or contact lenses and may also opt for multifocal optics. Multifocal ophthalmic lenses make use of two optical principles, refraction and diffraction.
For illustrating the physical difference between these principles, in the present description, the wave model of light is adopted. In this model an electromagnetic wave is propagating in a particular direction with a particular speed, and having a particular wavelength, amplitude and phase.
Refraction is the deflection that a light wave undergoes when travelling from one medium, such as air or liquid, into another medium, such as glass or plastic, having different propagation velocities of the light wave.
Diffraction, in its most basic form, is based on the physical effect that light waves, when impinging on irregularities at an object, become a source of secondary light waves. These secondary waves may interfere with one another in a constructive and destructive manner. Constructive interference occurs when the optical path difference between waves arriving at a particular point is an integer multiple of their wavelength, such that their amplitudes add up in a reinforcing manner. Also called that the waves are in-phase. Destructive interference occurs when the difference in optical path length travelled by interfering light waves is an odd multiple of half of the wavelength, such that a crest of one wave meets a trough of another wave and the waves partly or completely extinguish each other. This is also called that the waves are out-of-phase.
A multifocal ophthalmic lens generally has a biconvex or plano-convex shape or a biconcave or plano-concave shape, the curvature and thickness of which is adapted to provide a first focal point at its optical axis by refraction. At one or both the anterior and the posterior surface of the lens a transmissive surface relief or diffraction grating may be provided, comprised of regularly or periodically spaced ridges and/or grooves, designed to diffract transmitted light, and arranged in concentrically rings or zones at a respective surface of the lens. The periodic spacing or pitch of the ridges and/or grooves substantially determines the points of destructive and constructive interference at the optical axis of the lens. The shape and height of the ridges and/or grooves control the amount of incident light that is provided at a point of constructive interference by diffraction. The points of constructive interference are generally called diffraction orders or focal points. The diffraction relief can be designed such as to provide a second and third focal point of a trifocal lens, different from the refractive focal point, for example.
Present multifocal ophthalmic lenses are generally designed using two well-known types of basic diffraction gratings or reliefs, that is the sawtooth type and binary type gratings or reliefs. In this description, the term sawtooth type or jagged type designates a class of transmission diffraction gratings or reliefs comprised of a plurality of repetitive, contiguously arranged, prism shaped transparent diffractive optical elements, DOEs, having a monotonic sloping light receiving surface, such as a linear or curved monotonic sloping light receiving surface. The term binary type reliefs, for the purpose of the present description, designates a class of transmission diffraction reliefs comprised of a plurality of repetitive, spaced apart rectangular or prism shaped transparent DOEs.
For operating as a lens, the repetition period or pitch of a jagged grating has to monotonically decrease in radial direction r from the center or optical axis of the lens. Or more specifically, if the first period starts in the center of the lens and the second period starts at (1*k)0.5, where k is a constant, then the third period starts at (2*k)0.5, the fourth at (3*k)0.5 and so on. Accordingly, in diffractive optics it is advantageous to represent the grating in the so called r2 space. That is, the parameter along the horizontal axis varies with r2, such that the period occurs at equidistant repetitions.
Calculation of the focal points, i.e. the diffractive orders, of such basic reliefs is well known and straightforward for the person skilled in the art of diffractive optical lenses. In general, for use as an ophthalmic lens, the period or pitch of the basic reliefs or gratings is selected to have the first and/or second diffraction orders to provide the target focal points. This, because with these basic reliefs most of the light is diffracted in the lower diffraction orders. In the design process, the relief is constructed having an amplitude profile, such to arrive at a desired intensity profile of the light coupled in the refractive focal point and diffracted in the first and/or second diffraction orders of these basic gratings or reliefs. However, such an approach does not automatically lead to an optimal distribution of the light that incidents the lens, because an amount of light is also distributed into higher diffraction orders, that are not used, which makes tuning or controlling of the relative light distribution between the focal points of the lens difficult for different pupil sizes and that may significantly reduce the overall efficiency of the multifocal lens.
European patent 2 377 493 and European patent 2 503 962, for example, try to solve this loss of efficiency for trifocal intraocular lenses by superposing diffraction reliefs or gratings, each designed to individually provide one of the target diffractive focal points of the lens. The pitches of the reliefs or gratings have to be selected such that the second diffraction order of the one profile coincides with the first diffraction order of the other profile. Besides that the design freedom of such an intraocular lens is thereby limited to specific focal distances at which first and second diffraction orders of the different reliefs coincide, it will be appreciated that light diffracted into higher diffraction orders, not contributing to one of the target focal points, is still lost. Accordingly, these designs do not provide an effective remedy against diffraction loss in intraocular lenses.
International patent application WO2017/055503 discloses a superposition of different types of basic diffraction reliefs or gratings, such as the sawtooth type and the binary type, each having a same first order focal point. This joint focal point provides one of the target diffractive focal points of the lens. However, for the purpose of designing a multifocal lens, such as a trifocal lens, this design gets complicated as the other target focal point of the lens occurs with the summation of the superposed profiles, and hence cannot be calculated and targeted individually. beforehand.
European patent application EP 2 375 276 observes that controlling or tuning the light distribution in the focal points of diffraction reliefs or gratings comprised of sawtooth type and binary type DOEs, for example, generally designated as stepped DOEs, by varying the shape and height or amplitude of the optical transfer function of the diffraction grating, may result in diffraction gratings having sharp edges in their height profile, which are difficult to manufacture.
To this end, EP 2 375 276 discloses smoothing of the sharp edges of a stepped diffraction relief or grating, by any of curve approximation using sinusoidal and cosine functions, polynomial expressions, filtering or convolution integration using a super-Gaussian function. The smoothing has the effect that the sharp edges or steps of the sawtooth type or binary type DOEs are stretched or spread in the radial direction of the lens. EP 2 375 276 is, however, silent about providing different light distributions for different pupil sizes for a given set of target focal points.
Published US patent application 2006/0116764 discloses diffractive zones that can be disposed within a portion of a lens surface, referred to as the apodization zone, surrounded by a peripheral portion of the surface that is substantially devoid of diffractive structures. The diffractive zones can be separated from one another by a plurality of steps located at zone boundaries that have substantially uniform heights. Alternatively, the step heights can be non-uniform. For example, the step heights can progressively decrease as a function of increasing distance from the lens's optical axis. By this apodization, the light distribution in the refractive focal point relative to the diffractive focal points is tuned.
None of the above-mentioned prior art publications allow tuning of the light distribution in the target focal points individually, and differently for different pupil sizes, for example. Accordingly, there is a need for an improved ophthalmic lens design that provides freedom in targeting diffraction orders or focal points, and tuning or controlling of the relative light intensity in all the target focal points, in particular for different pupil sizes, avoiding as much as possible light diffracted in diffraction orders not contributing to target focal points, thereby providing an improved overall user experience.


A duty cycle correction circuit may include an error booster suitable for amplifying an input clock duty error, a driver suitable for driving an output clock based on the input clock, and a duty corrector suitable for correcting the output clock duty based on the duty error amplified by the error booster.

1. Field
Exemplary embodiments of the present invention relate to an integrated circuit design technology, and more particularly, to a duty cycle correction (DCC) circuit.
2. Description of the Related Art
In integrated circuit chips that operate based on a clock (e.g. a CPU, memory device, etc), it is important to accurately control clock duty. For example, in a memory device where data is inputted/outputted at a rising edge and a falling edge of a clock, it is assumed that the duty of the clock is approximately 50%. The timing between the rising edge and the falling edge is often distorted causing data to be inputted/outputted at the incorrect time. In order to prevent this from occurring, various clock-based integrated circuit chips have a duty cycle correction circuit that corrects the duty of the clock. When the duty of a clock is 50% it means the 'high' level period is substantially equal to the 'low' level period.
FIG. 1 is a block diagram illustrating a conventional duty cycle correction circuit.
Referring to FIG. 1, the duty cycle correction circuit includes a receiver (RX) 110, a driver 120, a duty detector 130, and a duty corrector 140.
The receiver 110 receives clocks CLK and CLKB inputted to the duty cycle correction circuit. For reference, the input clock CLK_INB is a complementary clock of the input clock CLK_IN. The driver 120 drives output clocks CLK_OUT and CLK_OUTB in response to input clocks CLK_IN and CLK_INB. The duty detector 130 detects the duty of the output clocks CLK_OUT and CLK_OUTB. The duty detection consists of detecting the 'high' level periods and 'low' level periods of the output clocks CLK_OUT and CLK_OUTB. The duty corrector 140 corrects the duty of the input clocks CLK_IN and CLK_INB based on a detection result of the duty detector 130. For example, when the duty detector 130 determines that the 'high' level period of the output clock CLK_OUT is too long, the duty corrector 140 increases 'low' level period of the input clock CLK_IN, and in an opposite case, the duty corrector 140 increases 'high' level period of the input clock CLK_IN. Since the driver 120 employs the clocks received by the receiver 110 and a duty correction value from the duty corrector 140 as an input, the output clocks CLK_OUT and CLK_OUTB, which are duty-corrected, may be outputted from the driver 120.
The feedback-type duty cycle correction circuit as illustrated in FIG. 1 increases or decreases 'high' pulse widths of the input clocks CLK_IN and CLK_INB incrimentally using a feedback detection result, and is locked when the degree of distortion of the duty is reduced below a predetermined margin. That is, the duty cycle correction circuit operates similarly to a delay locked loop (DLL), and requires a separate locking time until the duty is corrected, similarly to the delay locked loop.
When a locking time is required before the duty is corrected, a device having a repeated idle mode and an active mode needs to wait for the locking time to correct the duty (the device needs to wake-up). Then, the operation mode of the device is changed from idle mode to active mode.


Process for the production of shaped articles of niobium or tantalum by electrochemical etching of a niobium or tantalum sheet covered by a structured photoresist mask in an aqueous solution containing hydrofluoric acid, the etching being effected under electrochemical conditions under which strong noise is superposed on the etching current and the etching solution contains a water-soluble polymer.

In the production of capacitors, anodes based on niobium or tantalum are frequently used. These often consist of specially shaped sheets of said metals to which a paste containing niobium powder or tantalum powder is applied, for example by means of screen printing. The paste is then subjected to a sintering step, with a sintered body which is firmly connected to the shaped article of niobium or tantalum being formed.
The required shaped articles of niobium or tantalum can be etched, for example, out of niobium or tantalum sheets of suitable thickness.
It is known that niobium and tantalum can be etched both by plasma methods and other physical methods and by wet chemical methods. In the physical methods, however, the etching rates are very low. Structures of several 10 μm thickness, as are required for the production of shaped articles, therefore, cannot be produced in acceptable times by these methods. Moreover, the high costs for the equipment and the operation of units, as required for carrying out physical etching methods, may be mentioned as a further disadvantage.
It is therefore economically expedient to use only wet chemical methods for etching shaped articles from niobium or tantalum. Both purely chemical and electrochemical methods are suitable. Before the etching process, a photosensitive resist, a so-called photoresist, is applied to the niobium or tantalum layer to be etched. By suitable exposure to light, the photoresist can then be structured. The photoresist can then be removed, for example by washing out, in the parts where the etching process is to take place, so that the niobium or tantalum layer underneath can come into contact with an etching solution in these parts. The regions of the niobium or tantalum layer in which the photoresist is not removed are protected by this coating from attack by the etching solution.
Methods in which no mask need be produced from a photoresist, such as ECM (electrochemical machining) and the corresponding micro method, EMM (electrochemical micromachining), are also known. In these methods, the selective dissolution in predetermined parts of the workpiece is achieved by the very close approach on an appropriately shaped cathode to the workpiece. In the gap of a few 10 μm thickness between workpiece and cathode, very high current densities and accordingly also high etching rates can be achieved by intensive feeding of the etchant and virtually perpendicular etched edges can be produced. This method, however, requires suitable tools in the form of cathodes, which must be extremely resistant to etching for the application described. The production of such tools, which are manufactured individually from expensive materials, is very costly. This also applies to the required apparatus which generates the necessary intensive flow.
For the electroless wet chemical etching of niobium and tantalum, mixtures of hydrofluoric acid or fluorides with other acids and oxidizing additives, predominantly nitric acid, are generally described. The oxidizing agent has, inter alia, the task of preventing the formation of gaseous hydrogen which can adversely affect the adhesion of a mask comprising a photoresist on the metal.
The metals niobium and tantalum have a dense, firmly adhering, chemically very inert oxide layer and are therefore insoluble in the customary acids, with the exception of hydrofluoric acid. The oxide layer also makes it impossible to establish electrochemical potentials in a reproducible manner, so that very different data are to be found in the literature. However, normal potentials which were estimated from thermodynamic data are in the substantially negative range close to −1 V for niobium and tantalum. These metals can therefore be dissolved purely chemically in hydrofluoric acid without addition of oxidizing agents, but the resulting overvoltage of the hydrogen forming retards the dissolution and hence the chemical etching process.
The chemical etching of niobium and tantalum is as a rule therefore used only when the thickness of the layer to be etched is only a few micrometers. Such thin layers can still be completely etched in an acceptable time. Etching times of a few seconds are sufficient, so that conventional photoresists which are as a rule applied to the niobium or tantalum layers to be etched are not attacked.
U.S. Pat. No. 4,266,008 describes the production of superconducting circuits. For this purpose, a mask of photosensitive material is applied to thin niobium films having a thickness of from 0.5 to 5 μm and the niobium film is then etched in the parts which are not covered with the material, by means of an aqueous etching solution. The etching solution contains from 8.5 to 9% by weight of nitric acid, from 11.5 to 12% by weight of sulphuric acid and from 12.25 to 12.75% by weight of hydrofluoric acid. A 0.5 μm thick niobium layer can be completely etched with this etching solution in 10 s.
JP 56081680 A, too, discloses a process for etching niobium. A mixture of from 5 to 15% by weight of HF, from 2 to 6% by weight of NH4F, from 10 to 20% by weight of HCl and from 3 to 9% by weight of HNO3 is proposed.
M. Köhler in "Ätzverfahren für die Mikrotechnik [Etching methods for microengineering], WILEY-VCH-Verlag, 1998, page 306" describes an etching bath composed of 0.66 mol/l of (NH4)2S2O8, 0.27 mol/l of NH4F, 0.11 mol/l of citric acid and 1.43 mol/l of HNO3. The etching process is carried out at a temperature of 50° C.
In "Metallographisches, keramographisches, plastographisches Ätzen [Metallographic, ceramographic, plastographic etching], Gebr. Borntraeger Verlag, 6th edition, Stuttgart 1994, page 99", G. Petzow provides information on the microetching of niobium and its alloys with an etching solution which contains no fluorine compound. The etching solution consists of a mixture of equal parts of water, 30% strength by weight hydrogen peroxide and 32% strength by weight ammonia solution and is intended to be used at the boiling point. Since such a mixture is stable for only a short time, in particular at the boil, it is not suitable for the production of shaped articles of niobium and tantalum by means of etching.
The two metals niobium and tantalum can be etched not only with hydrofluoric acid but also with strongly alkaline solutions, to which, however, all known photoresists are insufficiently stable. Alkaline etchants are therefore not suitable for chemical machining. Owing to the evident difficulties due to the high acid concentrations and the necessity of adding oxidizing agents, the purely chemical methods for the production of shaped articles of niobium and tantalum are not very promising.
In principle, no oxidizing agents are required in electrochemical etching. Nevertheless, G. Petzow in "Metallographisches, keramographisches, plastographisches Ätzen [Metallographic, ceramographic, plastographic etching], Gebr. Borntraeger Verlag, 6th edition, Stuttgart 1994, page 99" specifies a mixture of 17 parts of 65% strength by weight HNO3, 17 part of 40% strength by weight HF and 66 parts of water for such a process. According to G. Petzow, the etching is effected with from 12 to 30 volt against a Pt cathode. In the electrochemical etching of niobium, no passivation, as occurs in the case of some metals in certain etchants, was described in the case of the anodic dissolution in HF. In the electrochemical etching of tantalum at a current density greater than 1 A/dm2, on the other hand, a layer of H2TaF7 forms, which layer hinders the further dissolution and increases the bath voltage.
A disadvantage of the wet chemical methods described is the intensive attack by the etching solutions used on the photoresist mask, which prevents destruction of niobium and tantalum layers having a thickness substantially greater than 10 μm. However, shaped articles of a corresponding thickness are required, for example, for the production of niobium or tantalum anodes. A further disadvantage is that single crystallites are exposed with the use of the etching solutions described, which results in a very rough surface in the etched parts.
It is therefore an object of the present invention to provide a process for etching shaped articles of niobium and tantalum which does not have said disadvantages and in particular permits the production of shaped articles having a thickness greater than 50 μm.


Aspects relate to methods for processing individual spectra acquired with a time-of-flight mass spectrometer to form a sum spectrum. The peak position of a peak and its total intensity are determined in an individual spectrum, and entries in an addition raster of the sum spectrum adjacent to the peak position are selected; then the total intensity is divided up into portions, wherein more of the total intensity is added to entries which are closer to the peak position than is added to entries which are further away from the peak position.

Most of the time-of-flight mass spectrometers used today acquire individual time-of-flight spectra in rapid succession. Hundreds to several hundred thousands of these individual spectra, which are acquired at a scanning rate of five thousand to thirty thousand spectra per second, are then immediately processed into a sum time-of-flight spectrum in order to obtain useful time-of-flight spectra with well-defined ion current signals (peaks) for the ion species of different masses. A method for improving the mass resolution has been used for some time; it includes adding the intensity of the peak only at the position of the peak maximum.
From the time-of-flight spectra, mass spectra are computed, using a calibrated transformation function. The purpose of many of these time-of-flight mass spectrometers is to determine the masses of the individual ion species as accurately as possible. Significant progress has been achieved in recent years; while approximately ten years ago a mass accuracy of 10 ppm was being aimed for (but rarely achieved), today the goal of 200 ppb is realistically on the horizon. As used here, the terms "ppm" (parts per million) and "ppb" (part per billion) for the accuracy refer to the relative accuracy of mass determination in parts per million or parts per billion of the mass, i.e., the relative deviation between the mass determined from a peak and the true value, averaged over many mass determinations. The precision (or reproducibility) is set statistically as sigma, the width parameter of the distribution of repeated measurements, with a tacit assumption of a normal distribution of the measurement variance. This width parameter gives the distance on the abscissa between the point of inflection and the maximum of the Gaussian normal distribution curve.
Nowadays, the target of 200 ppb is already being achieved for the reproducibility of the calculated masses in some high-quality types of time-of-flight mass spectrometers, but strangely not yet for the mass accuracy itself, i.e., for the accuracy of the mass determination. The masses are calculated using a calibration function, which represents the masses as a function of the times of flight of the peaks. If a smooth calibration curve is used to calculate the masses, for example a power series with only a few terms, as is theoretically required and expected, the values derived for the masses of different ion species reproducibly deviate from the true values toward slightly smaller or slightly larger values. These small deviations are of the order of a few hundred ppb, and are reproduced well in successive measurements. They thus point to systematic errors, but with erratic changes of size and direction of the systematic error within small mass intervals, hitherto not explainable.
The progress made in improving the reproducibility of the mass determination is attributable to a large number of individual improvements, such as improvement to the ion optics, stability of the electronics, thermal stability of the instrument, including the flight tube, resistance to vibrations, improvements to the ion detector and an increase in the sampling rate of the ion current measurements to four or five gigahertz all contribute to these improvements.
In time-of-flight mass spectrometers of this type, secondary electron multipliers (SEM) are used, without exception, in the ion detectors to measure the ion currents. They often take the form of multichannel plates (MCP), but there are also other embodiments. The multichannel plates have millions of channels of equal diameter each, which are arranged at an angle to the plane of the plates so that the ions cannot simply fly through. There are MCPs with channels of about 2 to 8 micrometers in diameter on the market. Two channel plates are usually connected in series with the channels at offset angles in order to achieve better amplification of the electron currents. The amplification can be set to values from 105 to 107 so that a single ion generates a signal of 105 to 107 secondary electrons, which are collected on an electrode. The detectors have a complicated structure in order not to generate any signal distortions; those skilled in the art are familiar with these arrangements, so that it is not necessary to explain these detectors in more detail here. In conjunction with a post-amplifier, they can be adjusted in such a way that a single ion generates a signal that stands out significantly from the electronic noise.
The process of avalanche-like secondary electron multiplication in the individual channels of the plates also results in a broadening of the amplified signal, however. The best ion detectors currently provide an electron current which is around 500 picoseconds wide from a single impinging ion. The signal widths are around one nanosecond or more if less expensive pairs of channel plates are used. Since the technology is mature, it is not to be expected that significant progress will be made here in the future.
Special electronic digitization units can be used for the temporal sampling and digitization of the electron current, whose integral over time is proportional to the ion current to a good approximation; these units are developed out of the known transient recorders and associated digital oscillographs. Nowadays, they operate with sampling rates of four to eight gigahertz. While the processing speed of other electronic components and systems doubles roughly every 1.5 to three years, the sampling rate in the field of transient recorders has not increased for a number of years. It is, however, to be expected that the digitization depth will improve from eight to ten or even twelve bits.
These special digitization units sample the electron current from the secondary electron multipliers in a fixed measuring time raster, at a sampling rate of five gigahertz, for example. The electron current from a single ion provides a series of five to fifteen measurement values above the noise for a conventional ion detector with full widths at half-maximum of 500 to 1000 picoseconds at a sampling rate of five gigahertz. If the digitized measurement values for ions of one mass from several individual spectra are summed, or if several ions of the same mass are detected in an individual spectrum, the signal widths become larger compared to the signal of an individual ion because residual focusing errors of the mass spectrometer, uncompensated effects of the initial energy distributions of the ions before they are pulsed out, and other effects come into play. At present, these effects still result in additional signal broadenings in the order of a few nanoseconds, usually dependent on the mass of the ions.
In time-of-flight mass spectrometers with orthogonal ion injection, a special measurement procedure is used as a rule. Since there is practically no background of erratically occurring scattered ions in these mass spectrometers, each single ion is significant in the analytical sense. In order to measure each single ion with a high degree of certainty, the electronic background noise is suppressed by using a measuring threshold that is so high that electronic noise is no longer measured. The measuring threshold can either be set, for example, electronically on the digitization unit or implemented in the software of the processing method. The amplification of the SEM is then set so that a single ion produces, on average, a signal with an amplitude of 10 to 15 counts above the measurement threshold, for example. This is done so that those ions that produce only a weak signal in the SEM are also measured. Since the impact of the ions only releases a few first-generation secondary electrons, the amplitude of the signals of individual ions varies roughly in accordance with a Poisson distribution. The SEM setting means that ions which release only a single secondary electron, and thus generate a signal of low amplitude, are also measured.
This measuring procedure leads to large regions in both the individual spectra and the sum spectrum being empty, without electronic noise, and the spectra contain only the signals of analytically significant ions. If, at a given time of flight, ion signals are present in practically every individual spectrum acquired, a very high-amplitude signal is generated at this point when the individual spectra are summed; but a low-amplitude signal in the sum spectrum may contain only the signals from ions which have occurred in only every hundredth or thousandth individual spectrum. Some analytical tasks require that around ten ions of a specific mass must be found in one million summed individual mass spectra, which requires around two minutes of measuring time.
As has been briefly mentioned above, this measuring procedure can be improved to increase the time-of-flight resolution of the peaks in the sum spectra. Years of experience have shown that improving the time-of-flight resolution also improves the time-of-flight accuracy because the accuracy is approximately inversely proportional to the resolution. A rule of thumb says that the mass can be accurately determined to within around 1/20 of the width of the peak profile. The resolution of the time of flight is defined as the time of flight divided by the width of the peak at half height, measured in units of the time of flight. Although the full width at half-maximum of an individual ion's peak is only 500 to 1500 picoseconds, depending on the quality of the detector, the summing of several peaks leads to a broadening because ions of exactly the same mass do not impact on the ion detector at exactly the same time of flight due to residual focusing errors in the mass spectrometer, uncompensated effects of the initial energy distributions of the ions before they are pulsed out, and particularly due to the characteristics of the ion detectors. It does not matter here whether the ions occur simultaneously in the same individual spectrum or sequentially in different individual spectra. The broadening of the ion peaks leads to lower time-of-flight resolution and accuracy, and after the times of flight have been converted into masses, it leads to lower mass resolution and lower mass accuracy also. In order to reduce the broadening, example embodiments in U.S. Pat. No. 6,870,156 add the peak intensities obtained from the digitized sequences of measurements of a peak (or even only partial intensities, such as the intensity of the highest measured value) in the sum spectrum only at the times of flight of the maximum measurement of the peak. An ion current signal is thus obtained in the sum spectrum whose width is determined only by the variance of the times of flight of the peak maximum and no longer by the full width at half-maximum of the ion detector. In this way an increased time-of-flight resolution is achieved. The statistical variances of the position of the peak maximum mean that digitized ion current signals with sequences of several intensity values are contained in the sum spectrum. The times of flight of the peaks and the overall intensities are then determined with the aid of a suitable peak detection algorithm.
In the prior art, multichannel plates with an internal channel diameter of around six micrometers were used. Incident ions can penetrate into the channels for some distance, which results in an average penetration depth and a variation of the penetration depths. The variation of the penetration depths is around 10 micrometers. This means that the flight distances also vary by these 10 micrometers. For a total flight distance of two meters, the variations of the flight distances and thus also of the times of flight amount to five parts per million (5 ppm). Due to the quadratic relationship between mass and time of flight, this results in mass variations of ten parts per million (10 ppm). To improve this, there was first a changeover to using multichannel plates with channel diameters of two micrometers; today even secondary electron multipliers with a plane first dynode are used, whose extraordinarily high planarity results in flight distance variations of only around 0.05 micrometers, i.e., mass variations of only 0.1 ppm (100 ppb). Similar improvements are also achieved for other residual ion-optical errors.
By improving the time-of-flight mass spectrometers, the variations in the times of flight of the peaks in the individual spectra caused by residual errors in the ion optics of the instruments become smaller and smaller. Thus, even if several ions occur, the width of the peak of these ions will, in the future, deviate less and less from the signal width of the electron current of a single ion. These improvements have consequences for methods according to U.S. Pat. No. 6,870,156 if these involve the intensities being summed only at the points of the time of flight with intensity maxima. If further improvements mean that the ion-optical variances increasingly disappear, the maxima of the measurements of a peak will appear increasingly at precisely the same time of flight. In the end, signals appear in the sum spectrum, which have intensity entries only at this one single position. For the signal detection methods, this means that the technique of forming centers of gravity (centroids) over several entries in the sum spectrum can no longer be used to achieve a more exact time-of-flight determination than corresponds to the time raster of the measurements in the digitizing unit. If a digitizing unit with a 5 gigahertz measuring rate is used, the times of flight of the ions of one species can only be determined with a best accuracy of 200 picoseconds. This results in systematic errors which cannot be corrected.
The problem of incorrect masses can be explained in more detail using the digitized ion peak which is shown in FIG. 2. If this peak is reproduced identically in a mass spectrometer of ideal quality, the ion intensities are always added at measurement raster location 3 on the abscissa in accordance with an embodiment of U.S. Pat. No. 6,870,156. However, since the peak, characterized by its center of gravity (in short "centroid"), is positioned at location 2.6 on the abscissa, and the abscissa shows time-of-flight intervals of 200 picoseconds each, the addition is always carried out at a wrong position with an error of 80 picoseconds with respect to the position of the centroid. If, for example, the ions with a mass of m/z=1000 atomic mass units appear at a time of flight of 40 microseconds, a systematic error of 2 ppm results for their time of flight, and 4 ppm for the mass. This is an extremely large error given a desired mass accuracy of 200 ppb. Even if improvements to the mass spectrometers are not yet so far advanced that this maximum error occurs, nevertheless this example shows that errors of this type cannot be accepted.
Similar considerations concerning incorrect times of flight of ion current signals also apply to the method which is disclosed in U.S. Pat. No. 7,412,334.
There is a need to provide method and apparatus with which individual spectra of a time-of-flight mass spectrometer are processed to give sum spectra which have both a higher time-of-flight resolution and a better accuracy in determining the times of flight of the peaks compared to a sum spectrum comprised of summed individual spectra.

Processing of ion current measurements in time-of-flight mass spectrometers