An electrosurgical medical device and method for creating thermal welds in engaged tissue. In one embodiment, at least one jaw of the instrument defines a tissue engagement plane carrying a conductive-resistive matrix of a conductively-doped non-conductive elastomer. The engagement surface portions thus can be described as a positive temperature coefficient material that has a unique selected decreased electrical conductance at each selected increased temperature thereof over a targeted treatment range. The conductive-resistive matrix can be engineered to bracket a targeted thermal treatment range, for example about 60° C. to 80° C., at which tissue welding can be accomplished. In one mode of operation, the engagement plane will automatically modulate and spatially localize ohmic heating within the engaged tissue from Rf energy application—across micron-scale portions of the engagement surface. In another mode of operation, a conductive-resistive matrix can induce a “wave” of Rf energy density to sweep across the tissue to thereby weld tissue.

1. Field of the Invention
This invention relates to medical devices and techniques and more particularly relates to a working end of an electrosurgical instrument that can apply energy to tissue from an engagement surface that can, in effect, independently modulate the Rf power level applied to tissue across localized micro-scale portions of the engagement surface, the Rf energy being delivered from a single source.
2. Description of the Background Art
In the prior art, various energy sources such as radiofrequency (Rf) sources, ultrasound sources and lasers have been developed to coagulate, seal or join together tissues volumes in open and laparoscopic surgeries. The most important surgical application relates to sealing blood vessels which contain considerable fluid pressure therein. In general, no instrument working ends using any energy source have proven reliable in creating a "tissue weld" or "tissue fusion" that has very high strength immediately post-treatment. For this reason, the commercially available instruments, typically powered by Rf or ultrasound, are mostly limited to use in sealing small blood vessels and tissues masses with microvasculature therein. The prior art Rf devices also fail to provide seals with substantial strength in anatomic structures having walls with irregular or thick fibrous content, in bundles of disparate anatomic structures, in substantially thick anatomic structures, or in tissues with thick fascia layers (e.g., large diameter blood vessels).
In a basic bi-polar Rf jaw arrangement, each face of opposing first and second jaws comprises an electrode and Rf current flows across the captured tissue between the opposing polarity electrodes. Such prior art Rf jaws that engage opposing sides of tissue typically cannot cause uniform thermal effects in the tissue—whether the captured tissue is thin or substantially thick. As Rf energy density in tissue increases, the tissue surface becomes desiccated and resistant to additional ohmic heating. Localized tissue desiccation and charring can occur almost instantly as tissue impedance rises, which then can result in a non-uniform seal in the tissue. The typical prior art Rf jaws can cause further undesirable effects by propagating Rf density laterally from the engaged tissue thus causing unwanted collateral thermal damage.
The commercially available Rf sealing instruments typically use one of two approaches to "control" Rf energy delivery in tissue. In a first "power adjustment" approach, the Rf system controller can rapidly adjust the level of total power delivered to the jaws' engagement surfaces in response to feedback circuitry coupled to the active electrodes that measures tissue impedance or electrode temperature. In a second "current-path directing" approach, the instrument jaws carry an electrode arrangement in which opposing polarity electrodes are spaced apart by an insulator material—which may cause current to flow within an extended path through captured tissue rather that simply between surfaces of the first and second jaws. Electrosurgical grasping instruments having jaws with electrically-isolated electrode arrangements in cooperating jaws faces were proposed by Yates et al. in U.S. Pat. Nos. 5,403,312; 5,735,848 and 5,833,690.
The illustrations of the wall of a blood vessel in FIGS. 1A–1D are useful in understanding the limitations of prior art Rf working ends for sealing tissue. FIG. 1B provides a graphic illustration of the opposing vessel walls portions 2a and 2b with the tissue divided into a grid with arbitrary micron dimensions—for example, the grid can represent 5 microns on each side of the targeted tissue. In order to create the most effective "weld" in tissue, each micron-dimensioned volume of tissue must be simultaneously elevated to the temperature needed to denature proteins therein. As will be described in more detail below, in order to create a "weld" in tissue, collagen, elastin and other protein molecules within an engaged tissue volume must be denatured by breaking the inter- and intra-molecular hydrogen bonds—followed by re-crosslinking on thermal relaxation to create a fused-together tissue mass. It can be easily understood that ohmic heating in tissue—if not uniform—can at best create localized spots of truly "welded" tissue. Such a non-uniformly denatured tissue volume still is "coagulated" and will prevent blood flow in small vasculature that contains little pressure. However, such non-uniformly denatured tissue will not create a seal with significant strength, for example in 2 mm. to 10 mm. arteries that contain high pressures.
Now turning to FIG. 1C, it is reasonable to ask whether the "power adjustment" approach to energy delivery is likely to cause a uniform temperature within every micron-scale tissue volume in the grid simultaneously—and maintain that temperature for a selected time interval. FIG. 1C shows the opposing vessel walls 2a and 2b being compressed with cut-away phantom views of opposing polarity electrodes on either side of the tissue. One advantage of such an electrode arrangement is that 100% of each jaw engagement surface comprises an "active" conductor of electrical current—thus no tissue is engaged by an insulator which theoretically would cause a dead spot (no ohmic heating) proximate to the insulator. FIG. 1C graphically depicts current "paths" p in the tissue at an arbitrary time interval that can be microseconds (μs) apart. Such current paths p would be random and constantly in flux—along transient most conductive pathways through the tissue between the opposing polarity electrodes. The thickness of the "paths" is intended to represent the constantly adjusting power levels. If one assumes that the duration of energy density along any current path p is within the microsecond range before finding a new conductive path—and the thermal relaxation time of tissue is the millisecond (ms) range, then what is the likelihood that such entirely random current paths will revisit and maintain each discrete micron-scale tissue volume at the targeted temperature before thermal relaxation? Since the hydration of tissue is constantly reduced during ohmic heating—any regions of more desiccated tissue will necessarily lose its ohmic heating and will be unable to be "welded" to adjacent tissue volumes. The "power adjustment" approach probably is useful in preventing rapid overall tissue desiccation. However, it is postulated that any approach that relies on entirely "random" current paths p in tissue—no matter the power level—cannot cause contemporaneous denaturation of tissue constituents in all engaged tissue volumes and thus cannot create an effective high-strength "weld" in tissue.
Now referring to FIG. 1D, it is possible to evaluate the second "current-path directing" approach to energy delivery in a jaw structure. FIG. 1D depicts vessel walls 2a and 2b engaged between opposing jaws surfaces with cut-away phantom views of opposing polarity (+) and (−) electrodes on each side of the engaged tissue. An insulator indicated at 10 is shown in cut-away view that electrically isolates the electrodes in the jaw. One significant disadvantage of using an insulator 10 in a jaw engagement surface is that no ohmic heating of tissue can be delivered directly to the tissue volume engaged by the insulator 10 (see FIG. 1D). The tissue that directly contacts the insulator 10 will only be ohmically heated when a current path p extends through the tissue between the spaced apart electrodes. FIG. 1D graphically depicts current paths p at any arbitrary time interval, for example in the μs range. Again, such current paths p will be random and in constant flux along transient conductive pathways.
This type of random, transient Rf energy density in paths p through tissue, when any path may occur only for a microsecond interval, is not likely to uniformly denature proteins in the entire engaged tissue volume. It is believed that the "current-path directing" approach for tissue sealing can only accomplish tissue coagulation or seals with limited strength.

Electrosurgical instrument and method of use


A process for preparing an angiotensin converting enzyme inhibitor. Phosphorus pentachloride is reacted with the carboxylic acid group of an amino acid to form an acyl chloride hydrochloride. The resulting hydrochloride salt is then coupled with a silylated amino acid in a non-aqueous medium to form a high yield peptide. The peptide is used as an angiotensin converting enzyme (ACE) inhibitor.

1. Field of the Invention
The present invention relates to a process for preparing an angiotension converting enzyme (ACE) inhibitor, and in particular to a process for preparing angiotension converting enzyme inhibitors such as intermediates of captopril, enalapril, quinapril and the like without using phosgene, diphosgene and triphosgene.
2. Description of the Related Arts
The synthesis of enalapril, an angiotensin coverting enzyme inhibitor which is used among other things in the treatment of blood pressure, by coupling amino acids has been disclosed in many patents. For example, in European Patent No. 0215335, enalaprils are prepared by reacting N-(s-ethoxycarbonyl-3-phenyl-propyl!-L-alanine with phosgene to form N-carboxylanhydride, followed by condensation with L-proline. This process uses noxious phosgene.
U.S. Pat. No. 5,359,086 discloses a process for the preparation of enalapril. According to the process, alkyl-L-alanine is reacted with a coupling agent, N,N-carbonyldiimidazole to form alkyl-L-alanine-N-carboxy anhydride. The alkyl-L-alanine-N-carboxy anhydride is then coupled with L-proline silyl ester hydrochloride to form the enalapril. The coupling agent, N,N-carbonyldiimidazole, is expensive.
In Spain Patent No. 544781, a process for preparing enalapril has been proposed. The process involves reacting alkyl-L-alanine with N-hydroxysuccinimide and dicyclohexylcarbodiimide (DCC) to form N'-succinimidyl ester and coupling the N'-succinimidyl ester with L-proline. However, it is hard to remove DCC.
U.S. Pat. No. 4,808,741 discloses a process for preparing pharmaceutically active carboxylalkyl dipeptides such as enalapril, lisinopril and the like. In the process, the amino acid group of a L-proline is protected with a benzyl protecting group. Subsequently, the protecting group is removed.

Process for preparing an angiotensin converting enzyme inhibitor

Industrial Technology Research Institute


In a luminescence device formed of one or plural layers of organic film between a cathode and an anode, at least one layer is a luminescence layer, and a luminescence molecule of a metal coordination compound having a basic structure represented by formula (1) MLmL′n and having a substituent on at least one of cyclic groups incorporated as a guest in a host material at a concentration of at least 8 wt. %, which is higher than a concentration at which a luminescence molecule of a similar structure but having no substituent exhibits a maximum luminescence efficiency to form the luminescence layer. As a result, a high-efficiency luminescence device is provided, which is less likely to cause concentration extinction even when a luminescence molecule is contained at a high concentration relative to the host material in the luminescence layer.

An old example of organic luminescence device is, e.g., one using luminescence of a vacuum-deposited anthracene film (Thin Solid Films, 94 (1982) 171). In recent years, however, in view of the advantages such as easiness of providing a large-area device compared with an inorganic luminescence device and a possibility of obtaining desired luminescence colors in view of the development of various new materials and drivability at low voltages, an extensive study related to forming a luminescence device of a high-speed responsiveness and a high efficiency has been conducted.
As described in detail in, e.g., Macromol. Symp. 125, 1–48 (1997), an organic EL device generally has a structure comprising upper and lower electrodes and a plurality of organic film layers between the electrodes formed on a transparent substrate. Basic structures thereof are shown in FIGS. 1(a) and (b).
As shown in FIG. 1, an organic EL device generally has a structure comprising a transparent electrode 14, a metal electrode 11, and a plurality of organic film layers therebetween on a transparent substrate 15.
In the device of FIG. 1(a), the organic layers comprise a luminescence layer 12 and a hole-transporting layer 13. For the transparent electrode 14, ITO, etc., having a large work function are used, for providing a good hole-injection characteristic from the transparent electrode 14 to the hole-transporting layer 13. For the metal electrode 11, a metal, such as aluminum, magnesium or an alloy of these, having a small work function is used for providing a good electron-injection characteristic. These electrodes have a thickness of 50–200 nm.
For the luminescence layer 12, aluminum quinolynol complexes (a representative example thereof is Alq3 shown hereinafter), etc., having an electron-transporting characteristic and luminescence characteristic are used. For the hole-transporting layer, biphenyldiamine derivatives (a representative example thereof is .alpha.-NPD shown hereinafter), etc., having an electron-donative characteristic are used.
The above-structured device has a rectifying characteristic, and when an electric field is applied between the metal electrode 11 as a cathode and the transparent electrode 14 as an anode, electrons are injected from the metal electrode 11 into the luminescence layer 12 and holes are injected from the transparent electrode 15. The injected holes and electrons are recombined within the luminescence layer 12 to form excitons and cause luminescence. At this time, the hole-transporting layer 13 functions as an electron-blocking layer to increase the recombination efficiency at a boundary between the luminescence layer 12 and hole-transporting layer 13, thereby increasing the luminescence efficiency.
Further, in the structure of FIG. 1(b), an electron-transporting layer 16 is disposed between the metal electrode 11 and the luminescence layer 12. By separating the luminescence and the electron and hole-transportation to provide a more effective carrier blocking structure, effective luminescence can be performed. For the electron-transporting layer 16, an electron-transporting material, such as an oxadiazole derivative, is used.
Known luminescence processes used heretofore in organic EL devices include utilizing an excited singlet state and utilizing an excited triplet state, and the transition from the former state to the ground state is called "fluorescence" and the transition from the latter state to the ground state is called "phosphorescence". And the substances in these excited states are called a singlet exciton and a triplet exciton, respectively.
In most of the organic luminescence devices studied heretofore, fluorescence caused by the transition from the excited singlet state to the ground state has been utilized. On the other hand, in recent years, devices utilizing phosphorescence via triplet excitons have been studied.
Representative published literature may include:    Article 1: Improved energy transfer in electrophosphorescent device (D. F. O'Brien, et al., Applied Physics Letters, Vol. 74, No. 3, p. 422 (1999)); and    Article 2: Very high-efficiency green organic light-emitting devices based on electrophosphorescence (M. A. Baldo, et al., Applied Physics Letters, Vol. 75, No. 1, p. 4 (1999)).
In these articles, a structure including 4 organic layers devices as shown in FIG. 1(c) has been principally used, including, from the anode side, a hole-transporting layer 13, a luminescence layer 12, an exciton diffusion-prevention layer 17 and an electron-transporting layer 11. Materials used therein include carrier-transporting materials and phosphorescent materials, of which the names and structures are shown below together with their abbreviations.    Alq3: aluminum quinolinol complex    α-NPD: N4,N4′-di-naphthalene-1-yl-N4,N4′-diphenyl-biphenyl-4,4′-diamine    CBP: 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline    PtOEP: platinum-octaethylporphyrin complex    Ir(ppy)3: iridium-phenylpyridine complex.

The above-mentioned Articles 1 and 2 both have reported structures as exhibiting a high efficiency, including a hole-transporting layer 13 comprising α-NPD, an electron-transporting layer 16 comprising Alq3, an exciton diffusion-preventing layer 17 comprising BCP, and a luminescence layer 12 comprising CBP as a host and ca. 6% of platinum-octaethylporphyrin complex (PtOEP) or iridium-phenylpyridine complex (Ir(ppy)3) as a phosphorescent material dispersed in mixture therein.
Such a phosphorescent material is particularly noted at present because it is expected to provide a high luminescence efficiency in principle for the following reasons. More specifically, excitons formed by a carrier recombination comprise singlet excitons and triplet excitons in a probability ratio of 1:3. Conventional organic EL devices have utilized fluorescence of which the luminescence efficiency is limited to at most 25%. On the other hand if phosphorescence generated from triplet excitons is utilized, an efficiency of at least three times is expected, and even an efficiency of 100%, i.e., four times, can be expected in principle, if a transition owing to the intersystem crossing from a singlet state having a higher energy to a triplet state is taken into account.
However, like a fluorescent-type device, such an organic luminescence device utilizing phosphorescence is generally required to be further improved regarding thedeterioration of luminescence efficiency and device stability.
The reason for the deterioration has not been fully clarified, but the present inventors consider it to be as follows based on the mechanism of phosphorescence.
In the case where the luminescence layer comprises a host material having a carrier-transporting function and a phosphorescent guest material, a process of phosphorescence via triplet excitons may include unit processes as follows:    1. transportation of electrons and holes within a luminescence layer,    2. formation of host excitons,    3. excitation energy transfer between host molecules,    4. excitation energy transfer from the host to the guest,    5. formation of guest triplet excitons, and    6. transition of the guest triplet excitons to the ground state and phosphorescence.
Desirable energy transfer in each unit process and luminescence are caused in competition with various energy deactivation processes.
Particularly, in a phosphorescent material, this may be attributable to a life of the triplet excitons, which is longer by three or more digits than the life of a singlet exciton. More specifically, because it is held in a high-energy excited state for a longer period, it is likely to react with surrounding materials and cause polymer formation among the excitons, thus incurring a higher probability of a deactivation process resulting in a material change or life deterioration, as we have considered.
Needless to say, a luminescence efficiency of an organic luminescence device is increased by increasing the luminescence quantum yield of a luminescence center material, but it is also an important factor for enhancing the luminescence intensity of the device to increase the concentration of a luminescence material in the luminescence layer.
The luminescence intensity is increased in proportion to the concentration of a luminescence material in a luminescence layer in the case of a low concentration (up to several wt. %) of the luminescence material in the luminescence layer. However, above several % or 7%, a deviation from the proportional relationship is observed, and the luminescence intensity is rather lowered to result in a worse efficiency. This phenomenon is reported in Japanese Laid-Open Patent Application (JP-A) 05-078655, JP-A 05-320633, etc., and is known as concentration extinction or concentration deactivation.
Actually, in the case of using Ir(ppy)3 in CBP as the host material, the best luminescence efficiency is attained at a concentration of ca. 6–7%, and the luminescence efficiency is rather lowered thereabove, down to about a half at 12% concentration and 1/10 or below at 100% concentration (Applied Physics Letters 4, vol. 75, 1999).
The phenomenon is caused by abundant presence of molecules in the triplet excited state waiting for luminescence in the case of a phosphorescence substance having a life of triplet exciton longer by 3 digits or more than the life of the singlet exciton. In this state, thermal deactivation of losing energy due to a mutual interaction of triplet excitons is likely to occur. This is called triplet-triplet extinction and is associated with a lowering in luminescence efficiency at a high current density. Further, it is also considered that due to a long retention time at a high energy state, the excitons have an increased probability of reacting with a surrounding material and forming polymers of excitons, thereby causing deactivation, or even leading to a material change or a deterioration of useful life.

Luminescence device and display apparatus


A single loudspeaker has a substantially single-point source of sound energy derived from multiple drivers to provide a surround sound effect. The surround sound is effective for listeners close to the single loudspeaker or substantially distant within a room. The physical size of the loudspeaker is convenient for placement on top of a computer monitor or television set. The single loudspeaker produces a dynamically variable energy gradient between the listener's right and left ears and the perception of sound emanating from changing locations in the space surrounding the loudspeaker. The placement of a plurality of these loudspeakers surrounding the expected listener location allows the coverage of larger spaces with separate dynamically variable energy gradient pairs.

The field of the invention pertains to audio loudspeakers used in plural to realistically recreate the direct and ambient sound of an audio only, or an audio visual work such as a movie or television program and, in particular, in a home theater setting to provide sound from all directions to the viewer-listener. This invention also pertains to audio loudspeakers used for reproducing in a more realistic manner audio recordings in general ("auralization").
Stereophonic sound systems utilizing two loudspeakers, both being forward of the listener, are common. More recently bass units (subwoofers) have been added as a third separate loudspeaker. The main purpose of adding this third speaker is to allow smaller left and right speakers, thus increasing the overall convenience of the sound installation. In home theater settings the two loudspeakers have been to either side of a movie or television screen with the bass unit placed in any convenient location. Since the bass unit location has not been generally considered critical, the bass unit has frequently been hidden behind or under any convenient piece of furniture. Such stereophonic systems have been very successful.
Four channel or quadraphonic sound systems comprising full-range right and left front stereo loudspeakers and full-range right and left rear loudspeakers were developed, however, the quadraphonic sound system was a marketing failure, particularly in the private home market. One of the reasons for the marketing failure is reputed to be the difficulty in placing four large separate loudspeakers in the proper locations about the listener for best acoustic reproduction which typically conflicts with other decorating and furniture placement considerations. Another reason often cited is the additional cost of the two full-range rear loudspeakers.
Recently, package systems have been introduced that comprise five physically small loudspeakers plus a larger subwoofer. The five small loudspeakers interfere less with room decor and the subwoofer location is flexible because of its frequency range. Long wires must be installed for the two rear loudspeakers and this factor has caused some customer resistance.
The Dolby® AC3™ system is now being marketed with five full-range loudspeakers or five small loudspeakers plus a subwoofer, however, customer acceptance has not yet been proven.
Applicant's previous U.S. Pat. No. 4,578,809 and U.S. Pat. No. 4,691,362 disclose dihedral loudspeakers with variable dispersion circuits. These circuits include delay lines that drive both high frequency drivers simultaneously within a loudspeaker plus circuit elements that differentiate the energy supplied to the drivers facing away from the expected listener location from the energy supplied to the drivers facing the listener location. This patent is incorporated by reference herewith.
Also, in the past, loudspeakers have been disclosed wherein a polar plot of the sound energy comprises a cardioid, the null in energy being on the axis of symmetry through the major lobe. Such a polar plot arises from loudspeakers as disclosed in Olson, Harry F., "Gradient Loudspeakers", Journal of the Audio Engineering Society, Vol. 21, No. 2, March 1973, pp. 86–93.
Taking the polar plot a step further to a hypercardioid (which can be accomplished by varying the driving signal delay between the physically spaced speaker elements), the plot comprises a major lobe and a minor lobe, both lobes being symmetric about the same axis with symmetric nulls to each side of the axis. Where the major lobe and minor lobe are the same size (dipole) the nulls face directly opposite each other and are symmetric about a cross axis in turn perpendicular to the axis of symmetry of the lobes as shown by Olson (see also U.S. Pat. No. 4,961,226). Unequal lobes cause the nulls to face in equiangular directions relative to the axis of symmetry. Such polar plots arise from loudspeakers also disclosed by Olson. "Dipole" loudspeakers are described by Olson as gradient loudspeakers with zero electrical delay between the driver elements.
"Dipole" loudspeakers have been placed next to side walls with difference signals produced by electronic processing of the stereo signals supplied to the sidewall speakers. Such an arrangement can provide double dipole sidewall loudspeakers with nulls facing the audience and the walls in an auditorium setting. Such a configuration can be created by selecting one of the modes of operation of the sidewall loudspeakers as described in U.S. Pat. No. 5,301,237. In contrast, U.S. Pat. No. 4,819,269 discloses sidewall loudspeakers that broadcast over a 180° arc. The former of these disclosures teaches use of a five or seven channel surround sound processor whereas the latter teaches a two (stereo) channel sound source with additive or subtractive electric combinations of the two channels fed to the sidewall and rearwall loudspeakers.
The inventor of above U.S. Pat. No. 4,819,269 further develops his additive or subtractive approach to two channels fed to two loudspeakers in an article, Klayman, Arnold I., "Surround Sound With Only Two Speakers", Audio, August 1992, pp. 32–37.
U.S. Pat. No. 4,847,904 and U.S. Pat. No. 5,117,459 disclose pairs of dihedral loudspeakers and additive or subtractive approaches to combining the electric signals from the right and left channels within the loudspeakers. In the former patent the outwardly directed drivers subtractively combine both channels and the inwardly directed drivers use a single channel. In the latter patent the channels are electrically combined in a different manner.
U.S. Pat. No. 4,888,804 discloses loudspeakers having the full range drivers directed to the listening area, limited range boundary drivers 180° out of phase directed a specific 65° from the full range drivers and in-phase limited range expansion drivers outwardly directed from the listening area. According to the patent, boundary drivers provide a cancellation of first arrival room boundary reflections as well as late arrival reflections. To restore the late arrival reflections which give a perception of spaciousness the in-phase expansion drivers restore the late arrival reflections.
Of interest is the research disclosed in Kantor, K. L. and DeKoster, A. P., "A Psycho-acoustically Optimized Loudspeaker", Journal of the Audio Engineering Society, Vol. 34, No. 12, December 1986, pp. 990–996; wherein the optimal angles of the direct sound and the ambient sound maxima to the listener are 26° and 54°, 0° being defined as directly forward of the listener. Such an arrangement is said to cause minimum interaural cross-correlation.
Also of interest are recent articles on binaural recording and loudspeaker reproduction as well as transaural recording and reproduction in Griesinger, David, "Theory and Design of a Digital Audio Signal Processor for Home Use", Journal of the Audio Engineering Society, Vol. 37, No. 1/2, January/February 1989, pp. 40–50; Griesinger, David, "Equalization and Spacial Equalization of Dummy-Head Recordings for Loudspeaker Reproduction", Journal of the Audio Engineering Society, Vol. 37, No. 1/2, January/February 1989, pp. 20–29; and Cooper, Duane H., and Bauck, Jerold L., "Prospects for Transaural Recording", Journal of the Audio Engineering Society, Vol. 37, No. 1/2, January/February 1989, pp. 3–19. The new loudspeaker surround sound technique disclosed below can be used to increase the robustness of the transaural techniques and significantly reduce the amount of signal processing required to achieve the desired acoustic effects.
Heretofore, stereo sound and surround sound have assumed multiple point sources for multiple channels with the point sources separated in space and optionally some cross-talk cancellation.

This patent is subject to a terminal disclaimer.


A method for operating a door-opening mechanism of a household appliance includes: providing a first signal using a door-opening sensor; providing a second signal using the door-opening sensor; and providing a third signal using the door-opening sensor. A total signal is calculated based on the first, second and third signals so as to determine a spatial direction from which a signal source originates.

Recently, customers have more and more often been requesting so-called fully integrated household appliances. A fully integrated household appliance is designed without handles. This means that the household appliance can be completely paneled. With such a household appliance, a door or drawer is no longer opened by mechanically pulling on a handle, but rather, by means of an appropriate mechatronic system. In this case, one or more sensors detect a command by a user, and subsequently an opening drive can open the door or drawer.
International application WO 2009/132813 A1 describes a generic fully integrated dishwasher without a handle. For this purpose, a decorative panel is spring-mounted on the door. Moreover, a sensor is provided to detect a relative movement between the decorative panel and the door. Sensors that can be used include especially a force sensor, a piezoelectric sensor, a contact sensor or proximity sensor. In order to reliably make a distinction between a useful signal and an interference signal, this device requires a commensurately high actuation force.
On the other hand, German utility model DE 20 2007 006 818 U1 describes a cabinet with drawers that is configured to recognize when a user acoustically expresses a door-opening command. For this purpose, sound sensors are provided, and it is proposed for a sound sensor to be connected to the drawers by means of a spring-loaded probe, and for another sound sensor to be arranged in the rear area of the cabinet with drawers. The distinction between a useful signal and an interference signal, the so-called signal distinction, is made by evaluating the differences in the propagation time of the signals of both sensors. In order to achieve satisfactory operation, several physically segregated sensors are needed, which involves a certain amount of assembly, contacting and wiring work.
International patent WO 98/037425 describes an acceleration sensor with a deflection sensor element.
German utility model DE 20 2007 015 532 U1 describes a tilt sensor that comprises a three-axis acceleration sensor.
Although the household appliances of the state of the art have proven their worth in daily use, there is a need for improvement, especially in terms of their usefulness.

Method for operating a door-opening mechanism of a household appliance


A lip seal for use in low torque, high pressure applications including a rigid retainer, a resilient body essentially covering the retainer and an inner support member. The inner support member provides spacing and orienting functions for the other elements. The inner support member has a radial dimension and outer diameter smaller than the inner diameter of an outer axial wall of the retainer so that a gap is maintained between the retainer and the inner support member under a variety of pressure, torque and shaft deflection conditions. Gap maintaining elements, preferably in the form of axially extending guides, prevent contact between the rigid seal elements. The guides may further comprise nub portions at one end which contain the inner support member in the cavity prior to installation on the shaft.

1. Field of the Invention
This invention relates generally to radial lip seals, and more particularly, to radial lip seals which can accommodate significant shaft deflection in an environment in which the shaft rotates at low speed, and under high torque conditions and in which the fluid being sealed attains high pressures.
2. Background Art
Lip seals are usually molded of a resilient elastomeric or polymeric material. They are secured in fluid tight relation to a housing and surround a rotating shaft which extends through an aperture in the housing wall. The sealing lip is in sealing relationship to the shaft to contain the fluid in the housing.
Lip seals components or elements include a rigid case or retainer to add rigidity and to unitize the seal assembly. The case also aids in the installation, withdrawal and retention of the seal relative to the housing. The resilient body includes a secondary seal to seal against the housing and one or more resilient sealing lips which are maintained in sealing contact with the shaft.
Lip seals experience a wide variety of uses in which operating temperature and pressure conditions, expected shaft speeds, and the make-up of the medium to be contained dictate the requirements of a particular construction. Typically, however, the rigid component or retainer is formed of hard plastic, such as phenolic, steel or stainless steel and the resilient lips are defined by elastomeric or polymeric members such as molded rubber, polytetrafluroethylene or other known materials. The resilient element may be molded as a single body or may comprise a plurality of separate elements connected together in fluid tight relation.
The nature of lip seal applications expose the seal to conditions of significant shaft movement relative to the surrounding housing. Shaft deflection relative to either the housing or the bore results in a wobble of the shaft during rotation of the shaft, also referred to as shaft run-out. A significant degree of shaft run-out often challenges the effectiveness of the lip seal.
Specific applications for lip seals may include automotive, appliance and industrial applications. Certain applications subject lip seals to extreme service conditions such as in air conditioning compressors, where the shaft is typically driven by a belt and pulley through an electric clutch, and in oil pumps which generally pressurize oil to high pressures, to thereby permit effective circulation of the oil through the engine and oil filter. Compressor and oil pump design typically results in shaft wobble, bending distortion and misalignment of the shaft axis relative to the housing aperture. Ideally, the lip seal assembly takes into account the established tolerances of the devices in which the lip seal is used in order to minimize the associated manufacturing costs.
Efforts to provide a lip seal to accommodate shaft run-out or misalignment include use of extended conical shapes, multiple lips and other variations and alterations of the resilient element. An effective arrangement is disclosed in U.S. Pat. No. 5,503,408, issued Apr. 2, 1996, and commonly assigned with this invention to John Crane Inc., Morton Grove, Ill. The seal disclosed and claimed in U.S. Pat. No. 5,503,408 embodies multiple resilient lips which provide for an auxiliary or alignment lip interposed between the shaft and the sealing lip for centering the lip seal. Under conditions of misalignment, the auxiliary lip contacts the underside of the primary sealing lip and causes a displacement of that lip in the direction of displacement of the shaft relative to the center of its associated housing bore. Displacement of the auxiliary lip causes the primary sealing lip to "follow" the shaft and, thereby, maintain the integrity of its sealing relation to the shaft. The lip seal described in U.S. Pat. No. 5,503,408 is used in relatively low pressure type applications.
The misalignment problem is also addressed in commonly assigned copending U.S. patent application Ser. No. 08/606,421, filed on Feb. 23, 1996, entitled "Improved Radial Lip Seal" and having at least one common inventor with this invention. The features of that invention include a sleeve bearing member which defines an annular body having a "T-shaped" cross section. An outer cylindrical surface of the annular body is sized to coincide with the inner axial surface central of an axial wall of an associated retainer. A radial edge of the annular body is in contact with the inner surface of an axial wall of the retainer so as to secure the bearing member in the assembly and retain it against rotation and radial displacement. A radial inner portion of the bearing member defines a cylindrical sealing surface sized to be in close supporting contact with the outer surface of the shaft. When installed in a housing, the sealing elements of the seal assembly are disposed inboard of the bearing member, thereby maintaining the bearing outward of the sealed chamber in the environment external to the housing. The bearing disclosed in the patent, which is interposed between the lip seal and the fluid being sealed within the housing, also acts to maintain orientation and position of the lip seal.
The bearing member disclosed in aforementioned U.S. patent application Ser. No. 08/606,421 may be either rigidly or resiliently mounted on, and in contact with, the outer diameter surface of a supporting retainer to provide shaft vibration dampening. In the case of a resilient mounting, the bearing member includes a radial wall in frictional engagement with the resilient body supporting the bearing member to restrict rotation of the bearing member relative to the housing.
All of the prior efforts which provide lip seal centering by means of a 0 bearing member work adequately in the low pressure environments for which they are intended. However, in the event that the fluid being sealed attains high pressures, the lip seal becomes subject to deformation from axially directed pressure forces, resulting from the high pressures acting on the radial area of the lip seal, which press the radial sealing lip against the bearing. At high pressures, the radial seal lip is further subject to folding over at the shaft, thereby resulting in a loss of sealing capacity.
To some extent, bearing members which are utilized in the efforts and examples described above maintain seal lip centering and also contain the seal lip in the desired orientation and position between the bearing and the high pressure fluid being sealed. However, bearings, by the nature of their construction and function, extend from the seal lip and provide rigid axial support to the retainer member relative to the shaft. In most instances, the outer diameter of the bearing is flush against the inner diameter of the rigid retainer member, so that any shaft deflection causes the bearing to impart that deflection to the retainer, thereby maintaining a predetermined relative orientation between the lip seal and the rotating shaft. Dampening action of a resilient mounting between the bearing and the retainer member absorbs the majority of the deflection. However, even in the resilient mounting example, the abutment of the bearing member with the resilient retainer subjects the bearing to continual repeated stress, which over extended periods of time can cause the deterioration and destruction of the bearing.
The present invention addresses the needs of the seals in some applications to accommodate a greater amount of pressure and inflexibility which results from the increased pressure sealed fluid environments. The ability of the improved lip seal according to the present invention to accommodate great pressures allows for the elimination of expensive case pressure drain systems that are presently required for high pressure applications.


A right angle drill (1) includes a motor housing (6) which defines therein a hole (18) for accommodating a motor field system (3), a cut-out (15) formed in the underside of the motor housing (6) from the front end toward the rear of the tool (1), and a light unit (16) slidably fitted in the cut-out (15). The light unit (16) is a plate member having an arcuate cross section so as to define an inwardly curved rear (i.e., inner) surface (16a) along its entire length. The unit's inner surface (16a) conforms to the inner surface of the accommodating hole (18) of the motor housing (6). The light unit (16) additionally includes a protrusion (17) at the front outer surface thereof. Furthermore, the protrusion (17) contains a pair of LEDs (21) for illuminating objects below an output spindle (12) to which a bit can be attached.

1. Field of the Invention
The present invention generally relates to electric power tools. More particularly, the present invention relates to an angle drill which includes a cylindrical motor housing and a top housing which is coupled to an end of the motor housing and from which a spindle protrudes at a right angle with respect to the motor housing.
2. Description of the Related Art
Certain known angle drills include a cylindrical motor housing which defines therein a hole to accommodate a motor and a top housing coupled to the forward end of the motor housing. The angle drill further includes an output spindle extends inside and out of the top housing at a right angle with respect to the motor housing. Additionally included in a certain type of angle drill is one or more illuminants (such as light emitting diodes, or LEDs) for providing light in the location below the output spindle in order to facilitate work in dark or dimly lit environments. Typically, such an illuminant(s) is embedded in the space within the motor accommodating hole of the motor housing except for the top portion of the illuminant, from which light is emitted.
While achieving its intended objective, the forgoing conventional arrangement suffers from a number of deficiencies that reduce the utility of the device. For example, as the illuminant or light unit protrudes into the motor accommodating hole of the motor housing, the illuminant may restrict the installation position of the motor's field system within the motor accommodating hole. The illuminant may additionally hinder the removal of the field system from the motor housing during repair or servicing.
Moreover, the motor housing must be reshaped depending on the presence or absence of the illuminant in the tool, thus increasing the manufacturing and other related costs of the drill.

Right angle drill with an improved structure for accommodating a light assembly


A plasma display panel in which a front panel (1) including at least display electrodes (6) and a dielectric layer (7), and a rear panel (2) are faced to each other, to form a discharge space (14) therebetween, and a discharge gas is filled into the discharge space (14). A protective layer (8) made of magnesium oxide containing at least one element of silicon and aluminum added thereto is provided over the dielectric layer (7). The discharge gas contains at least xenon and hydrogen. The concentration of one of the silicon and the aluminum in the protective layer (8) ranges from 30 to 50,000 ppm inclusive. The concentration of the hydrogen is up to 10,000 ppm.

A plasma display panel (hereinafter referred to as a PDP) is basically made of a front panel and a rear panel. The front panel includes: glass substrate; stripe-like display electrodes, each formed of a transparent electrode and bus electrode on one principle surface of the glass substrate; a dielectric glass layer over the display electrodes working as a capacitor; and a protective layer made of magnesium oxide (MgO) formed over the dielectric layer.
The glass substrate is manufactured by the float method, which is used to make a large and flat area. In the display electrodes, a paste containing silver (Ag) to ensure electrical conductivity is applied to the transparent electrodes made by a thin-film forming process, in a predetermined pattern. Then, the pattern is fired to form bus electrodes. A dielectric layer is formed by applying and firing a dielectric paste to cover the display electrodes made of transparent electrodes and bus electrodes. Lastly, a protective layer made of MgO is formed over the dielectric layer using the thin-film forming process.
On the other hand, the rear panel includes: a glass substrate; stripe-like address electrodes formed on one principle surface of the glass substrate; a dielectric layer covering the address electrodes; barrier ribs formed on the dielectric layer; and phosphor layers formed on the dielectric layer between the respective barrier ribs to emit light of red, green, or blue.
The front panel and the rear panel are hermetically sealed with their electrode-forming sides facing to each other. A discharge gas, such as neon(Ne)-xenon(Xe), is filled into a discharge space partitioned by the barrier ribs at a pressure ranging from 400 to 600 Torr. In the PDP, selectively applying an image signal voltage to the display electrodes generates a gas discharge, and ultra-violet rays generated by the discharge excite the respective phosphor layers to emit light of red, green, and blue. "All about plasma display panels" (co-authored by Heiki Uchiike and Shigeo Mikoshiba, published by Kogyo Chosakai Publishing Inc. on May 1, 1997, p. 79-80) discloses an example of displaying color images in such a manner.
A method of dividing one frame of image into a plurality of sub fields (SF) for gradation representation is used to display images. In this method, one SF is divided into an initializing period, addressing period, sustaining period, and erasing period, to control discharge. As a technique of performing stable address discharge during the addressing period for selecting pixels to be lit, Japanese Patent Unexamined Publication Nos. H10-334809, 2003-132801, and 2004-103273 disclose a technique of adding silicon (Si) or aluminum (Al) element to MgO of each protective layer in a concentration ranging from several hundred parts per million to several percents, to improve the electron emission characteristics of the protective layer.
Further, Japanese Patent Unexamined Publication No. 2000-267625 and "The component-specific characteristics and the latest developments of PDPs" (published by JOHOKIKO Co., Ltd. on Mar. 26, 2004, p. 216-218) disclose a technique of changing the discharge waveform during the initializing period into a generally rectangular pulse to have a gradual slope and inhibiting variations in address discharge voltage caused by variations in the shape of each discharge cell or difference in the charged state of the phosphors.
However, recently, there has been growing expectations on image display devices with higher definition, higher gradation, and lower power consumption, such as a high-definition television screen. For full-specification high-definition television screens 24 in. in diagonal that have particularly been expected, the number of pixels is 1920×1125 and the pitch of discharge cells is as small as 0.15 mm×0.48 mm. Such a high-definition PDP poses a problem in that decreases in brightness and efficiency become particularly apparent.
Measures taken to address this problem are to increase the brightness and efficiency by setting the Xe concentration of the discharge gas in the PDP to at least 5%, which is higher than the conventional concentration, or using barrier ribs arranged in a double cross. However, when the Xe concentration of the discharge gas in the PDP is set to at least 5% or barrier ribs arranged in a double cross is used to increase brightness, considerable increases in driving voltage and more unstable address discharge cannot provide high-quality images. When the Xe concentration increases, increases in the amount of Xe ions and MgO more likely to be sputtered shorten the life of the protective layer.
Generally, a method of adding the Si or Al element to MgO to increase electron emission from MgO is employed to address the problem of unstable discharge caused by increases in driving voltage. However, even though this method can make driving voltage slightly smaller in than the case of using a protective layer made of MgO only, the method cannot stabilize address discharge for a high-definition PDP having a relatively long addressing period.
Particularly for a high-definition PDP having an increased Xe concentration of at least 5%, addition of Si or Al to MgO to speed up address scan, stabilize address discharge, and decrease the voltage causes the following problems. When the PDP is attempted to be lit by a method using wall charge on the dielectric layer during the initializing discharge, the driving voltage is lower than that of a PDP using the conventional MgO protective layer. However, excellent characteristics of electron emission from the MgO protective layer even erase the wall charge formed during the initializing period, thus causing lighting failures (addressing failures) and deterioration of image quality.
When a gradually-sloping voltage waveform is used to stabilize address discharge and decrease address voltage, lighting failures (addressing failures) occur more prominently.

Plasma display panel with stabilized address discharge and low discharge start voltage


A ballast hopper car door control apparatus and method for controlling a pivoting hopper discharge control member on a railroad ballast car or the like, includes a drive shaft extending through the discharge control member at the pivot point. A transmission is connected to the drive shaft and is driven by a reversible electric motor. The motor is controlled via a radio receiver which receives motor control signals from a remote radio transmitter. When there are a plurality of ballast cars on a train, each car has a receiver which responds to a different address sequence. The remote transmitter is operable to selectively send any of the different address sequences so that a single selected car can be remotely controlled. Multiple hoppers on a single car are controllable by a single receiver.

The invention relates to a hopper door opening control apparatus and method for controlling a hopper discharge control member on a railroad ballast car.
Railroad ballast has traditionally been discharged and/or spread by specially designed hopper cars called "ballast cars". In such cars, the ballast is discharged through hopper doors positioned beneath the hopper. When such doors are positioned directly beneath the car, ballast discharged therefrom must be spread by hand, a labor intensive task, or by an additional specially equipped railroad car.
These problems were addressed in U.S. Pat. No. 3,654,872 ('872 patent) in which a ballast car has four hoppers, each of which is provided with a bottom-mounted discharge opening with a discharge control member inserted therein. The discharge openings are centered over a rail and each discharge control member is a pivotable structure with a pair of side walls extending at an angle outward from an arcuate top surface. A bottom wall connects the side walls and a pair of end walls extend past the side walls to form channels on either side of the discharge control member. The discharge control member is attached at a pivot point positioned below the discharge opening. The arcuate top surface covers the discharge opening when the discharge control member is pivoted to a center position. When the discharge control member is pivoted to one side or the other, the discharge opening is partially opened and ballast is released through the channel formed by one of the angled side walls and the end walls and is thus directed to an associated side of the railroad rail. By selectively pivoting the discharge control member, a proper amount of ballast is directed to a desired position which minimizes or eliminates subsequent spreading requirements. On ballast cars containing pairs of side-by-side hoppers, ballast can be selectively distributed inside or outside of each rail to further minimize spreading requirements.
While representing a significant improvement over prior ballast hopper cars, the hopper car door discharge control member in the '872 patent is controlled by a hand-operated lever. Thus, the control opening or openings on each ballast car must be set by hand when the train is stationary and can not be adjusted once the train is in motion.
It is clear that a need exists for an improved ballast car hopper door control apparatus and method which is power driven and which is remotely controllable to allow adjustment while a train including the ballast car is in motion. Such an apparatus and method should also provide for the selective adjustment of any one ballast car in a train carrying multiple ballast cars and of multiple hoppers on a single ballast car.

Ballast hopper door control apparatus and method with independently and selectively actuated motors in response to uniquely coded signals


The invention relates to a light emitting device consisting of one or more light sources coupled to a light guide containing diffuser particles having a refractive index close to the refractive index of the core of the light guide. The diffuser particles cause a scattering of the light emitted from the light sources so that light emitted from the light emitting device has colour variation imperceptible to the human eye and small and gradual variations in intensity.

It is often necessary to combine the output from one or more light sources in an optical system. This may involve mixing light of the same wavelength from single or multiple sources or may involve mixing light of different wavelengths from multiple sources. A particularly important example is the production of white light by combining the output from discrete red (R), green (G) and blue (B) LED's. Efficient white light production from RGB LED arrays is a crucial enabling technology for the widespread use of LEDs for general lighting. RGB LED arrays are far more energy efficient than known LEDs based on phosphors. Improvements in the energy efficiency and effectiveness of mixing light, and in particular mixing light from LEDs, are therefore desirable to enable use of LED arrays in place of phosphor and related conversion systems to produce white light. Energy efficiency in lighting is usually measured in lumens provided per Watt of power used to supply these lumens.
An important factor is that the human eye is very sensitive to slight variations in colour. Therefore, one problem encountered in the mixing of light is that the required degree of colour uniformity, wherein colour variations in the resultant light are imperceptible to the human eye, cannot be achieved by current mixing methods without unacceptable losses.
Zhao, F. et al, "Optical Elements for Mixing Coloured LEDs to Create White Light", conference paper 4776-35 at SPIE International Symposium on Optical Technology (SPIE's 47th Annual meeting, July 2002), published in Solid State Lighting II: Proceedings of SPIE volume 4776, pages 206–214, (2002) disclose an experimental investigation into the problems encountered and illustrates the deficiencies of the current state-of-the-art. Zhao, F. et al disclose using optically clear, acrylic light guides of square and circular cross section and of various lengths (76 mm, 152 mm, 305 mm) to mix red, green and blue light from an RGB LED array comprising 18 LED's.
The light guides were not found to significantly improve the beam uniformity in terms of illuminance and colour and there was no appreciable difference in the quality of the light produced by the different shaped light guides. The system energy efficiency deteriorated as a function of length as expected. The only improvement in illuminance and colour uniformity was achieved by diffusing the output ends of the light guides, which incurred further deterioration in efficiency.
Generation of white light is not the only application requiring efficient mixing of laser diode or LED output. Photo-curing of cements, such as dental cement requires a uniform illumination of the photosensitive material. Existing systems based on light guides produce uneven illumination giving unsatisfactory curing.
Hence, there is a need for a means of combining the output from one or more light sources to achieve output light with good uniformity of both colour and intensity across the output area. It is also desirable to have the ability to combine light from multiple sources without greatly increasing the angular spread of the input light and to make full use of the lumens supplied by the one or more sources.


A process and apparatus for the continuous production of organometallic compounds from a metal precursor and an alkylating agent. The reactants are delivered separately to a reaction centre (26) in a distillation column (2) wherein the reaction is maintained at a predetermined temperature to allow collection of the vaporised organometallic compound from the top of the column and removal of the waste products from the bottom of the column.

The present invention relates to an improved process and apparatus for the production of organometallic compounds, in particular organo compounds of Group 3a metals, especially trimethylgallium.
Organometallic compounds such as trimethylgallium are commonly employed as a gallium source in the fields of epitaxial semi-conductor growth and/or processing, vapour or plasma etching, plasma deposition or thin film deposition, for example metalorganic chemical vapour deposition (MOCVD). The compounds are generally prepared using a batch process wherein the reactants are fed into a reaction vessel and the product is collected once the reaction is complete. Trimethylgallium is normally prepared by means of such a batch process using gallium trichloride and a suitable alkylating agent such as a Grignard reagent, Lithium reagent or trialkylaluminium. This process provides compounds that are sufficiently pure but requires the use of large reaction vessels to produce a sufficient yield of product. The production rate of the compound is also limited due to the necessity to charge the reaction vessel, add specified amounts of the reactants, allow the reaction to take place and then collect the product and clean the vessel before commencing the process again. Cleaning the equipment between runs of the reaction may also lead to increased contamination of the product.
GB-A-2 123 423 (The Secretary of State for Defence) relates to the preparation of trialkylgallium compounds using a dialkylether. However, such a reagent can result in the product containing oxygen impurities. DE 11 58 977 (Siemens-Sciuckertwerke AG) also describes a process for the preparation of trialkylgallium compounds, whereby one equivalent of gallium trichloride is added to three equivalents of an aluminium trialkyl in solution in a hydrocarbon solvent or an ether. The process is carried out as a batch process to enable sufficiently pure product to be obtained. Similarly, Inorg. Synth (1974) 15, 203-7 and Chemical Abstracts, vol. 81, no. 17, 28 October 1974 (1974-10-28) and TR. Khim, Khim. Tekhnol (1973), (4), 40-41 relate to the preparation of trialkyl metal compounds using batch processes.
It is an aim of the present invention to provide an improved process and apparatus for the preparation of organometallic compounds, in particular the production of trimethylgallium, which overcomes the above mentioned drawbacks.
Accordingly, a first aspect of the present invention provides a continuous process for the preparation of an organometallic compound comprising the steps of delivering a metal precursor and an alkylating agent separately to a reaction centre, allowing the precursor to react with the alkylating agent, maintaining the reaction centre at a predetermined temperature to cause vapourisation of the organometallic compound and collecting the organometallic compound.
A second aspect of the present invention provides an apparatus for the preparation of an organometallic compound, the apparatus comprising at least two delivery conduits and a distillation column having a reaction centre and an outlet wherein each conduit transports a metal precursor and an alkylating agent respectively to the reaction centre to allow the reactants to react together, the temperature of the apparatus being maintained such as to allow collection of the vapourised organometallic compound from the outlet thereby enabling continuous production of the organometallic compound.
The process of the present invention may be used to prepare any organometallic compound wherein the product is a volatile liquid and the by-products are less volatile.
The continuous process for the preparation of organometallic compounds requires the reactants to be fed separately into a reaction section which is preferably provided in the centre of the distillation column. Preferably the outlet is provided at or near the top of the column for collection of the product and a further outlet is provided at or near the base of the column for removal of any waste products. The equipment is maintained at specified temperatures to control the rate of removal of the product from the top of the reaction column, with the non-vapourised waste products being removed from the base of the column. The continuous delivery of the reactants in specified amounts and at a predetermined rate into the reaction section, together with the maintenance of a specified temperature/pressure differential in the column enables a continuous production of the organometallic compound to be achieved. The rate of addition of the reactants may be controlled by means of appropriate flow controllers.
The rate of removal of the product from the top of the column should be carefully controlled to avoid a build up of the product in the column and a consequence loss of the product from the base of the column with the waste. Suitable conventional instrumentation systems such as a flow controller and temperature/pressure differential, may be used to maintain the required rate of removal of the product.
The continuous process relies on an equilibrium being set up in the column such that the product goes up the column and the waste products move down for their removal at the base, for example by means of a simple overflow leg. A number of factors effect the maintenance of the equilibrium, such as the temperature of the column, the addition rates of the reactants and the take off rate of the product. The conditions employed will vary according to the reactants and the organometallic compound being produced. The temperature is preferably fixed and the main control for a set of addition rates will then be the take off rate of the product.
Preferably, the distillation column for use in the present invention is fitted with a boiler at the base and a condenser at the top, the design of which will be dependent on the heat of the reaction to be carried out in the column. Importantly, means should be provided to allow the control of the reflux ratio applied to the top of the column and to remove the heat produced during the reaction from the reaction zone.
Any suitable distillation column may be used for carrying out the process of the present invention such as packed or plate distillation columns. The column should be equipped with sufficient plates in a stripping section to ensure removal of all the product from the stream leaving the base of the column and sufficient plates in the rectifying section to ensure the pure product leaves the top of the column.
Preferably, the metal precursor is added in a suitable solvent, such as toluene. It is preferable to prime the reaction centre with the solvent prior to commencing the reaction. Preferably, the solvent has a lower volatility than the organometallic compound to allow the pure product to be collected from the top of the column while the solvent leaves the base of the column with the by-products.
The reaction centre is preferably heated prior to commencing delivery of the reactants to the reaction centre in order to achieve a steady reflux. Preferably alkylating agent is added to the reaction centre prior to the metal precursor to ensure there is an excess amount of agent present.
Collection of the product is preferably commenced once a constant temperature corresponding to the boiling point of the product is recorded near to the top of the column, preferably around 2-5 cm from the top of the column. Preferably, collection of the product is halted if a rise in temperature is recorded and re-commended once the temperature drops back to the boiling point of the product.
The process of the present invention is particularly suitable for the preparation of Trimethylgallium in a continuous fashion by the reaction between trimethylaluminium (TMA) and gallium trichloride in a suitable solvent. The reaction is extremely exothermic and virtually instantaneous and it is desirable to move heat as quickly as possible from the reaction zone in order to prevent unwanted side reactions.
The reaction centre is preferably heated to a temperature between 120xc2x0 C. to 140xc2x0 C, more preferably 130xc2x0 C. until a steady reflux is achieved. The reactants may then be added, preferably commencing with the TMA. The ratio of active ingredients in the column should be such that there is an excess of TMA at all times to ensure full conversion of the gallium trichloride to trimethylgallium. A ratio of 5:1 TMA to gallium trichloride is preferred but other ratios may be used, such as 4:1 or 3.5:1.
The TMA and GaCl3 may be added at any predetermined rate depending upon the production rate of product required. For example, the TMA and GaCl3 may be added at a rate of 90 g/hr and 75 g/hr respectively to give a production rate of 30 g/hr. Alternatively, addition rates of 250 g/hr and 315 g/hr may be used to provide a production rate of 115 g/hr.
Collection of the trimethylgallium is commenced once a steady temperature of 56xc2x0 C. is maintained near the top of the column.
The solvent is preferably one which is less volatile than the trimethylgallium, such as toluene to ensure that pure product is collected as a vapour.

Process and apparatus for production of organometallic compounds


An oligopeptide having an amino acid sequence. Glu Pro Gly Asn Ser Glu Ile Leu Pro Thr Leu Lys. and variants thereof; immunogenic conjugates obtained therefrom; antibodies produced by means of said conjugates and which specifically recognize human plasma glutathione peroxidase (pl.GPx); methods for assaying human plasma glutathione peroxidase (pl.GPx); and assaying kits. The invention is useful in the medical diagnosis, treatment and monitoring of pathologic conditions induced by a variation in pl.GPx, for example, hepatic tumors, acute rejection of renal or hepatic graft, renal insufficiency and selenium deficiency.

Three types of human glutathione peroxidase have been characterized: plasma glutathione peroxidase (pl.GPx), intracellular glutathione peroxidase (c.GPx) which is essentially active on hydrophilic substrates, and glutathione peroxidase which is active on phospholipid hydroperoxides as well as on other lipid substrates (PHGPx). These enzymes catalyse the reduction of hydroperoxides (H.sub.2 O.sub.2 or ROOH) by glutathione (GSH). These enzymes are selenoproteins which contain a selenocysteine within their active site. c.GPx and pl.GPx are homotetramers whereas PHGPx is exclusively monomeric Biochem. Biophys. Acta, 839, 62-70 (1985).
Originally purified from plasma J. Biol. Chem., 262, No.36, 17398-17403 (1987); Arch. Biochem. Biophys., 256,No.2, 677-686 (1987), pl.GPx represents 0.007% of the total plasma protein mass. pl.GPx has also been isolated from human maternal milk J. Nutr., 121, No.8, 1243-1249 (1991).
Of glycoprotein nature, pl.GPx exists in the form of a homotetramer of a molecular weight of 94 kDa J. Biol. Chem., 262, No.36, 17398-17403 (1987). Each subunit, characterized by a molecular weight of 21.5 to 23 kDa J. Biol. Chem., 262, No.36, 17398-17403 (1987); J. Biochem., 108, 145-148 (1990), contains a selenocysteine in its active site.
Recently, a study performed in rats has shown that pl.GPx is predominantly synthesized by the renal cell (Yoshimura et al. J. Biochem. 109; (1991); 918-923) whereas another study has shown that a tumorous hepatic cell line (Hep G2) of human origin is capable of synthesizing this pl.GPx (AVISSAR et al. J. Biol. Chem. 264; 1989; 15850-15855).
Given the low concentrations of plasma glutathione, the principal role of pl.GPx remains uncertain. The specific activity of pl.GPx is about ten times lower than that of c.GPx Arch. Biochem. Biophys., 256, No.2, 677-686 (1987).
The primary sequence of human pl.GPx was determined from the cDNA and published by Takahashi et al. J. Biochem., 108; (1990); 145-148. It was not possible to completely sequence the pl.GPx and to identify the N-terminal end because of the glycosylation affecting this end. The exact number of residues per subunit therefore remains unknown.
pl.GPx differs considerably from c.GPx from the structural point of view:. absence of glycosylation and intramolecular disulphide bridges for the cellular form Arch. Biochem. Biophys., 256, 677-686 (1987); Blood, 73, 318-323 (1989), weak sequence homology between the two enzymes (of the order of 44% Nucleic Acids Res., 15; (1987); 5484; Nucleic Acids Res., 15; (1987); 7178).
Measurement of the pl.GPx level in plasma is a good indicator of a possible state of selenium deficiency in the body. Within the framework of experiments designed to quantify the influence of a deficiency and then of a supply of selenium in man, it has been shown that the average glutathione peroxidase levels do not vary at the same rate depending on whether the plasma form or the cellular form is involved. Thus, the pl.GPx level in plasma begins to increase from the early days of treatment to reach a normal value after two to four weeks. The time necessary for the value of the normal level of c.GPx to be reestablished is longer: three to four months Amer. J. Clin. Nutr., 41; (1985); 735-747.
Furthermore, and following the studies previously carried out in rats, a number of renal pathologies could be detected by the measurement of pl.GPx.
None of the known methods of assaying enzymatic activity currently permit the specific assay of pl.GPx in biological fluids or in tissue extracts.
The most commonly used method of assaying glutathione peroxidase activity involves an enzymatic coupling calling into play the regeneration of reduced glutathione by the glutathione reductase present in excess; this reaction is accompanied by the oxidation of a reduced cofactor, NADPH, whose rate of disappearance can be easily monitored as a function of time. Under these conditions, the kinetics of oxidation of NADPH corresponds to the kinetics of oxidation of glutathione and, consequently, to the kinetics of reduction of hydroperoxide. However, no hydroperoxide substrate specific for pl.GPx or c.GPx exists.
Discrimination between the activity of c.GPx and the activity of pl.GPx is therefore impossible at the present time.
Given the fact that the specific activity of c.GPx is approximately ten times greater than that of pl.GPx, a contamination of 1% by mass by c.GPx will introduce an overestimation of the order of 10% of the pl.GPx activity. A slight haemolysis occurring in a blood sample can thus introduce a large error into the calculation of the pl.GPx activity of the circulating plasma or the serum.

Method of the specific immunoassay of human plasma glutathione peroxidase, kit for its implementation, oligopeptides and antibodies specific for the method


In various examples, a neurostimulation interconnection apparatus apparatus includes a substrate disposed within a header of a neurostimulation device. A spring contact is mounted to the substrate. The spring contact is oriented to accept and apply a clamping force to a proximal contact of a lead body to electrically couple the proximal contact of the lead body with the spring contact with insertion of the proximal contact within the spring contact. A trace is disposed on the substrate from the spring contact to a pin of a feedthrough of the neurostimulation device. The trace electrically couples the spring contact with the pin of the feedthrough.

Implantable neurostimulators are an emerging area of healthcare. Advances in microelectronics, rechargeable power sources, and high-density mechanical systems have led to smaller, more robust, and cost-effective componentry for implantable devices. Stimulating lead technology has also improved, allowing for large numbers of contacts to be positioned near neural targets to improve selective activation and individually tailor therapy.
Lead connector technology, however, remains expensive and bulky compared to the other advanced components in neurostimulator systems. Most of the cost of present-day multicontact neurostimulator is associated with lead connectors, and their size and volume limit package shape and shrinkability.

Neurostimulator interconnection apparatus, system, and method


An integrated circuit (IC) including unit power control, leakage reduction circuit for controllably reducing leakage power with reduced LdI/dt noise in the IC and, an activity prediction unit invoking active/dormant states in IC units. The prediction unit determines turn on and turn off times for each IC unit. The prediction unit controls a supply voltage select circuit selectively passing a supply voltage to a separate supply line at the predicted turn on time and selectively blocking the supply voltage at the predicted turn off time.

1. Field of the Invention
The present invention generally relates to the reduction and control of power consumption in a microprocessor or system comprised of a plurality of clocked components or units.
2. Description of the Related Art
Semiconductor technology and chip manufacturing advances have resulted in a steady increase of on-chip clock frequencies, the number of transistors on a single chip, the chip die size itself and, a corresponding decrease in chip supply voltage (Vdd). Generally, the active power consumed by a given clocked unit is primarily from switching chip capacitive loads and increases linearly with the clock frequency. Thus, not withstanding the decrease of chip supply voltage, active chip power consumption has increased as well.
Moreover, independent of operating frequency, chip leakage or standby power increases linearly with the number of chip transistors. Especially for chips and circuits in the insulated gate field effect transistor (FET) technology commonly referred to as CMOS, a substantial portion of chip leakage is subthreshold leakage. Subthreshold leakage is current in a that flows (drain to source) through the FET channel even when the FET gate to source voltage is insufficient to turn on the FET, i.e., below threshold voltage (Vt) of the FET. S. Borkar, "Design Challenges of Technology Scaling," IEEE Micro, vol. 19, no. 4, July/August 1999, pp. 23–29, describes how subthreshold leakage power is increasing as a percentage of total power dissipation. This percentage increase is occurring because as Vdd is falling, Vt must remain more or less constant. Thus, even if chip active power is reduced to zero, i.e., effectively the chip is shut down, subthreshold leakage continues to consume power.
Consequently, both at the chip and system levels cooling and packaging costs have escalated as a natural result of these chip power increases. For low end systems (e.g., handhelds, portable and mobile systems), where battery life is crucial, reducing net power consumption is important; but, it must come without degrading performance to unacceptable levels. Thus, particularly with state of the art central processing units (CPUs), even with the advances in CPU architecture, whether a scalar, superscalar, vector, or some other type of processor, this increase in microprocessor power dissipation has become a major stumbling block for performance gains.
A scalar processor fetches and issues/executes one instruction at a time. Each such instruction operates on scalar data operands. Each such operand is a single or atomic data value or number. Pipelining within a scalar processor introduces what is known as concurrency, i.e., processing multiple instructions in a given clock cycle, while preserving the single-issue paradigm.
A superscalar processor can fetch, issue and execute multiple instructions in a given machine cycle. In addition, each instruction fetch, issue and execute path is usually pipelined to enable further concurrency. Examples of super scalar processors include the Power/PowerPC processors from IBM Corporation, the Pentium Pro (P6) processor family from Intel Corporation, the Ultrasparc processors from Sun Microsystems and the PA-RISC and Alpha processor families from Hewlett Packard (HIP) Company.
A vector processor typically is pipelined and can perform one operation on an entire array of numbers in a single architectural step or instruction. For example, a single instruction can add each entry of array A to the corresponding entry of array B and store the result in the corresponding entry of array C. Vector instructions are usually supported as an extension of a base scalar instruction set. Only those code sections that can be vectorized within a larger application are executed on the vector engine. The vector engine can be a single, pipelined execution unit; or, it can be organized as an array or single instruction multiple data (SIMD) machine, with multiple, identical execution units concurrently executing the same instruction on different data. For example, typically, Cray supercomputers are vector processors.
A synchronously clocked processor or system has a single, global master clock driving all the units or components comprising the system. Occasionally, by providing ratioed derivatives of the clock may cycle, e.g., clock doubling, a particular sub-unit faster or slower than the main or master clock frequency. Normally by design, such clocking decisions are predetermined and preset statically. For example, the Intel Pentium 4 processor clocks its integer pipe twice as fast as the chip master clock, ostensibly using what is known in the art as double-pumping or wave-pipelining. Such clock doubling techniques boost processor execution rates and performance. However, bus and off-chip memory speeds have not kept pace with processor computing logic core. So, most state of the art processors have off-chip buses and caches that operate at frequencies that are integral sub-multiples of the main processor clock frequency.
Usually, these clock operating frequencies are fixed during system design. This is the reason current generation processor complexes may have multiple clocking rates. Occasionally, double pumping and wave-pipelining are used in higher end machines to alleviate any performance mismatch between the processor and external buses or memories.
Typically, clock gating is used to reduce active power. A. Chandrakasan and R. Brodersen, ed., "Low-Power CMOS Design," IEEE Press, 1998, describes power reduction using synchronous clock-gating wherein the clock may be disabled at a point of regeneration, i.e., within a local clock buffer (LCB) feeding a particular chip region, component or latch. At a coarser level of control, clocks are gated along functional boundaries. At a finer level of control, clocks are gated at individual latches. For example, H. Sanchez, "Thermal management system for high performance PowerPC microprocessors," Digest of Technical Papers, IEEE COMPCON, 1997, teaches gating clocks to different execution units based on instructions dispatched and executed in each cycle.
Coarse idle control can be synthesized during code generation by the compiler inserting special instructions, included in the instruction set architecture; alternately, these instructions can be issued dynamically by the operating system, e.g., when servicing a special interrupt or at certain context-switch times. At the coarsest control level, a special sleep-type instruction or command can be issued; this special sleep command can generate a disable signal that stops the clock to a selected portion of the chip for a period of time. This same special sleep command can be used to disable the instruction fetch process. Likewise an implicit wake up begins when the disable signal is negated or after the sleep period; or, the wake up can be accomplished with an explicit, asynchronous interrupt. As is well known in the art, various power-down modes can be provided (e.g. nap, doze or sleep) with the clock distribution tree selectively disabled at various levels of the LCB hierarchy. At the next finer level of granularity, the compiler can insert special instructions to start gating off the clock(s) to a given unit, e.g. the floating point unit, whenever the compiler can statically predict the computation phases.
A hardware idle self-detect mechanism may be included. The idle self-detect logic can be designed to detect localized processor idle periods. Upon detection the local unit triggers clock-disabling and/or local supply voltage reduction (Vdd and/or ground) for some or all of the idling unit region(s). Each unit disables its own clock and/or local supply voltages for a period of time. A wake-up is similarly self-initiated, based on new work received by the disabled or sleeping unit.
For finer idle control, dynamically defined signals gate local clocks (but, previously not supply voltages) cycle-by-cycle. For a typical superscalar machine for example, the processor determines during instruction decode which functional unit pipes could be clock-gated during the subsequent execute cycles. This works well in a processor with "in-order" issue mechanisms, so that the gating decision can be made unambiguously and sufficiently ahead of time, i.e., at decode or dispatch time. If the instruction class information is preserved in a centralized issue queue on an entry-by-entry basis, then such gating signals can also be generated at issue time even for an out-of-order issue queue.
In any pipelined data path, redundant clocking can be detected dynamically and selectively prevented, e.g., propagating a Data Valid flag or bit along the logic pipeline; this Data Valid flag is set only when the data generated on a cycle is valid. Then, the Data Valid flag for each logic stage can be used as a clock enable for setting the stage's output latches. Thus, invalid data is not unnecessarily clocked through the succeeding pipeline stages in what may be referred to as fine-grain, valid-bit based, pipeline stage-level clock gating.
U.S. Pat. No. 6,247,134 B1 to Sproch et al., entitled "Method and System for Pipe Stage Gating Within an Operating Pipelined Circuit for Power Savings" Jun. 12, 2001 teaches a processor with logic to identify as inconsequential any newly received operand that would not change in the pipeline in a prior cycle's computation by the first stage of logic. Detection of such an invariance condition signal as inconsequential can be used to disable the clock to the first stage and, then, successively to following stages.
Ohnishi, M., Yamada, A., Noda, H. and Kambe, T. "A Method of Redundant Clocking Detection and Power Reduction at the Rt Level Design," Proc. Int'l. Symp. On Low Power Electronics and Design (ISLPED), 1997, pp. 131–136, discuss other, more elaborate idle detection mechanism to prevent various kinds of redundant latch clocking.
Coarse-grain unit-level clock-gating is beneficial in cases when the processor is executing a sequence of a certain functional class of instructions, e.g., integer-only or floating-point-only instructions. When the input workload is such that the processor sees integer code only, the clock regenerator(s) to the floating point unit may be disabled. Similarly, during the floating-point-only operation, clocks to the integer unit can be disabled. Coarse idle control is normally effected locally with software through serial instructions or using hardware to detect idle periods. Fine idle control, normally, is effected also locally during instruction decode by avoiding unnecessarily propagating invalid or inconsequential data.
There are at least two problems arising from coarse idle control that must be addressed. These are especially a concern when supply voltage gating is employed. First, large transient current drops and gains can cause unacceptable levels of inductive (LdI/dt) noise in on-chip supply voltage. Second, overhead cycles are required for gating off and on processes to maintain correct functional operation. Switching between gated and enabled modes too frequently for finer grain phase changes in the workload results in an unacceptable performance hit.
Further, state of the art fine idle control relies on locally generated gating signals or conditions for pipeline stage-level clock-gating, e.g., based on a data-invalid or inconsequential-operand condition. These state of the art approaches do not generate the gating signal on a predictive or anticipatory basis. So, the timing requirements are often critical because the gating signal must be available in advance of assertion and asserted for a suitable duration for error-free clock-gating operation. Gowan, M. K., Biro, L. L. and Jackson, D. B., "Power considerations in the design of the Alpha 21264 microprocessor," Proc. 1998 ACM/IEEE Design Automation Conference, pp. 726–731, (June 1998) discuss how these constraints can significantly complicate design timing analysis, even resulting in a degraded clock-frequency performance. While in spite of these problems, clock-gating may reduce average active (or "switching") power in a processor, it still does not reduce static or standby power.
Instead, supply voltage gating (also called power or Vdd gating) may be used for reducing static or leakage power. Even when a FET or CMOS circuit block inactive (off), current leakage from Vdd to ground still occurs as subthreshold leakage. So, these CMOS circuits consume power even with clocks disabled or held constant, i.e., high or low. As noted above, this subthreshold leakage component of total power is rising due to technology scaling effects, reducing the gap between Vdd and the device threshold voltage, Vt. Supply voltage gating gates Vdd or ground (GND) to the FET/circuit, eliminating the current flow path. So, an additional "header" or "footer" FET or device is in the path circuit current flow path from Vdd to ground. The header/footer device is on during normal activity, i.e., when the circuit is gated active. When gated off or idle, the header/footer device is turned off to electrically isolate the complementary FET pair from either supply rail, i.e., the Vdd rail or the GND rail. L. Wei, K. Roy, V. De, "Low Voltage Low Power CMOS Design Techniques for Deep Submicron IC's," Proc. of IEEE In'i. Conf. On VLSI Design, January 2000, pp. 24–29, describes a straightforward application of Vdd gating.
However, application of the Roy method may result in a large performance degradation with unreliable circuit operation from large (uncontrolled) surges in the power supply lines and, potentially, an increase in total average power. There are two reason for the performance degradation. First, adding the supply gating control circuitry increases the basic delay of the gated circuit block because it adds impedance in the circuit's supply path. If the performance overhead is reduced by allowing sharp turn-ons and turn-offs, then LdI/dt noise may be considerable. In any case, supply voltage gating adds some performance overhead, which is the second source of performance degradation. Gating circuits on and off with a graceful ramp-up/down to minimize LdI/dt can incur a delay up to as much as several hundred processor cycles in resuming/stopping normal operation. As a result, total average power consumption can actually increase from being gated on and off too frequently. In particular, even if the average utilization is low, average power consumption can increase if the added switching or active power of the gating control device and related circuitry is more than the leakage power saved.
Current gating methods and especially, supply gating methods, whether coarse—or fine-grain, are termed non-predictive. The typical voltage gating signal is generated locally based on events and logical conditions that are tracked within a temporal window of a few cycles.
Thus, there exists a need for gated power supply designs that are able to hide the currently large performance overheads, especially is in processor designs, without impaired circuit reliability such as from increased inductive noise on the supply voltage rails.

Processor with low overhead predictive supply voltage gating for leakage power reduction

International Business Machines Corporation


A method of and an apparatus for cleaning a thin disk-shaped workpiece that is required to have a high degree of cleanliness, e.g., a semiconductor wafer, a glass substrate, a liquid crystal display, or the like. The method of cleaning the workpiece includes a plurality of cleaning steps, and comprises the steps of holding a workpiece, and performing a liquid jet cleaning of a surface of the workpiece in a first portion of plural cleaning steps. The method further comprises the step of performing a liquid jet cleaning of the surface of the workpiece in a latter portion of the plural cleaning steps.

1. Field of the Invention
The present invention relates to a method of and an apparatus for cleaning a workpiece, and more particularly to a method of and an apparatus for cleaning a workpiece that is required to have a high degree of cleanliness, e.g., a semiconductor wafer, a glass substrate, a liquid crystal display, or the like.
2. Description of the Prior Art
As semiconductor devices have become more highly integrated in recent years, circuit interconnections on semiconductor substrates have become finer and the distance between each circuit interconnections have become smaller. When semiconductor wafers are processed, small particles such as particles of semiconductor material, dust particles, crystalline protrusive particles, or the like often tend to be attached to the semiconductor wafers being processed. If a particle greater than the distance between interconnections exists on a semiconductor substrate, then the particle will short-circuit interconnections on the semiconductor substrate. Therefore, any undesirable particles on a semiconductor substrate have to be sufficiently smaller than the distance between interconnections on the semiconductor substrate. Such a problem and a requirement hold true for the processing of other workpieces including a glass substrate to be used as a mask, a liquid crystal display, and so on. To meet the above requirement, there have been practiced various cleaning procedures for removing fine particles or submicron particles from semiconductor wafers.
For example, heretofore one practice has been to use a brush of nylon, mohair or the like, or a sponge of polyvinyl alcohol (PVA) to scrub a surface of a semiconductor wafer. This process is called a scrubbing cleaning process. Further, there have been other practices, one of which is an ultrasonic cleaning process in which water having ultrasonic vibrational energy applied thereto is supplied to a surface of a semiconductor wafer, and another of which is a cavitation jet cleaning process in which high pressure water containing cavitation (i.e., cavitation bubbles) therein is supplied to a surface of a semiconductor wafer. Also, a cleaning process which combines two or three of the above processes is known in the art. A scrubbing cleaning process using a brush of nylon, mohair, or the like is effective to remove particles having diameters of 1 .mu.m or larger from semiconductor wafers. However, such a scrubbing process fails to produce an appreciable cleaning effect on submicron particles smaller than such particle sizes, and adversely produces scratches over a surface of the semiconductor wafer. Further, when a number of semiconductor wafers are cleaned by the brush, particles are attached to the brush which in turn contaminates subsequent semiconductor wafers.
Particles having diameters of submicron size can be removed from semiconductor wafers by another scrubbing process sing a sponge of polyvinyl alcohol (PVA). The sponge of PVA has a tendency to entrap particles therein. This scrubbing process is, however, ineffective where a certain amount of particles are entrapped by the sponge. That is, the sponge of PVA does not have a long service life without suitable regeneration.
As described above, in case of a scrubbing cleaning process using a brush or a sponge, the brush or the sponge is contaminated during the cleaning process. Therefore, in the case where a semiconductor wafer to which a great number of particles are attached, as in the case of a semiconductor wafer which has been polished, is cleaned using the brush or the sponge, a brush or the sponge must be cleaned or replaced, resulting in imposing the serious burden on the operator.
Further, in case of cleaning a semiconductor wafer having a circuit pattern thereon, as particles are smaller and gaps into which particles are entered are smaller, the semiconductor wafer cannot be cleaned only by the scrubbing cleaning process.
On the other hand, an ultrasonic cleaning process and a cavitation jet cleaning process do not require cleaning by a brush or a sponge, and can remove some particles which cannot be removed by the scrubbing cleaning process.
Further, an ultrasonic cleaning process and a cavitation jet cleaning process are effective up to a degree of several ten or several hundred particles on a surface of a semiconductor wafer having a diameter of eight inches (200 mm).
However, in case of a semiconductor wafer which has been subjected to CMP (chemical mechanical polishing) process, the semiconductor wafer carries hundreds of thousands of particles. Thus, the ultrasonic cleaning process and the cavitation jet cleaning process are ineffective, because they can reduce the number of particles only to a degree of several thousands or several tens of thousands of particles.

Method of and apparatus for cleaning workpiece


Disclosed is an air-permeable film imparted with oil repellency, including a porous body having a surface coated with an oil-repellent agent. The oil-repellent agent contains a linear fluorine-containing hydrocarbon group represented by —R1C5F10CH2C4F9 or —R2C6F13, where R1 and R2 are each independently an alkylene group having 1 to 12 carbon atoms or a phenylene group, and the porous body is a porous formed body composed of ultra-high molecular weight polyethylene fine particles that are bound together. This air-permeable film is imparted with oil repellency without significantly reducing its air permeability.

Porous formed bodies composed of ultra-high molecular weight polyethylene fine particles that are bound together (hereinafter sometimes referred to as "porous bodies of ultra-high molecular weight polyethylene") are widely used as air-permeable films in various applications due to their excellent properties such as air permeability, low friction coefficient, and abrasion resistance. For example, Patent Literature 1 shows a sheet for suction holding as an example of such applications, and Patent Literature 2 shows, as another example of the applications, a tip filter adapted to be attached to the tip portion of a suction nozzle of a liquid suction device.
The air-permeable films described above are attached to various products (hereinafter also referred to as "workpieces"). An adhesive layer is provided on a part of the top or bottom surface of the air-permeable film, and the air-permeable film is placed on a workpiece such that the adhesive layer is in contact with the workpiece. Then, the interior of the workpiece is evacuated through a vent hole of the workpiece (formed on the opposite side of the workpiece from the air-permeable film placed thereon) so as to suck and hold the air-permeable film. This attachment technique has not only an advantage that it is easier to place the porous body of ultra-high molecular weight polyethylene but also an advantage that the air-permeable film is less likely to be displaced from the position where it is placed. The adhesive layer is preferably made of a pressure-sensitive adhesive because it can be easily removed to replace the air-permeable film by a new one, but instead, a hot-melt adhesive, a thermosetting adhesive, a tackiness agent, or the like may be used.

Air-permeable film imparted with oil repellency