In order to connect an electric PE (protective earth) contact with an electrically conductive connector housing, PE (protective earth) contact that is realized in the form of a pin or socket contact and arranged in a sleeve of an insulating supply insert that is directly contacted with the connector housing and fixed by means of a screw connection.

1. Field of the Invention
The invention pertains to an electric contact in an insulating housing that features several sleeves and is connected to an electrically conductive housing by means of a screw connection.
An electric contact of this type is required for contacting a PE (protective earth) conductor or protective cover with an electrically conductive metal housing.
2. Description of the Related Art
Electric contacts to be inserted into insulating connector inserts of a plug-type connector typically feature a mating region and a connecting region that is realized in the form of a screw connection, soldering connection or crimping connection.
However, such contacts cannot be used if a so-called PE (protective earth) contact is required as a protective measure against dangerous shock currents, e.g., when working with a 230 V operating voltage, wherein this contact produces an electric connection with a grounded point of a power source.

Electric contact for contacting a protecting conductor with conductive housing


A lockdown device for securing a tubing hanger to a production member comprises a lockdown member which is mounted on the production member and is movable into and out of engagement with a corresponding locking profile on the tubing hanger, and an actuating mechanism for moving the lockdown member into and out of engagement with the locking profile.

The present invention relates to a device for locking a tubing hanger to a tubing spool or the like in a subsea completion system. More particularly, the invention relates to such a device which is operable independently of both the tubing hanger and the tubing hanger running tool.
A typical prior art completion system for subsea oil and gas wells comprises a subsea wellhead which is installed at the upper end of a well bore, a production member which is connected to the top of the wellhead, and a tubing hanger which is landed in the production member and which supports a production tubing string that extends through the well bore and into the well. During installation and workover operations, the subsea completion system is often connected to a surface vessel through a low pressure riser which in turn is connected to a subsea blowout preventor ("BOP") that is secured to the top of the production member.
The tubing hanger is normally installed in the production member using a tubing hanger running tool ("THRT"). In addition, once the tubing hanger is landed in the production member, a lockdown mechanism is usually actuated to secure the tubing hanger to the production member. A typical lockdown mechanism includes a lock ring which is supported on the tubing hanger and is expandable into locking engagement with a corresponding groove that is formed in the production member. Furthermore, once the tubing hanger is secured to the production member, a release mechanism on the THRT is actuated to release the tubing hanger from the THRT.
Thus, prior art THRT's must usually include a lockdown tool for actuating the lockdown mechanism on the tubing hanger and a release tool for actuating the release mechanism on the THRT. Moreover, these tools are often operated by hydraulic pressure which is supplied to the THRT through a hydraulic umbilical that is connected to the surface vessel.
When employing such a hydraulically operated THRT, however, safety and contingency concerns often require that a subsea test tree ("SSTT") and a shear joint also be used. In this arrangement, the SSTT is connected to the top of the THRT, the shear joint is connected to the top of the SSTT, and the entire assembly is lowered on a running string through the low pressure riser and the BOP. In addition, the hydraulic umbilical for the THRT is run along side the running string and then routed to the THRT through the shear joint and the SSTT.
The SSTT and the shear joint allow for a controlled shut-in of the well in the event of a blowout or other emergency. When such an event occurs, the valves in the SSTT are closed, the lower BOP pipe rams are sealed around the SSTT and, if necessary, the upper BOP shear rams are actuated to sever the shear joint and thereby separate the running string from the SSTT. After the well has been brought back under control, the lower portion of the severed shear joint can be retrieved and a replacement shear joint then re-connected to the SSTT.
Thus, the SSTT and the shear joint allow for hydraulic control of the THRT to be easily re-established. Once the replacement shear joint is connected to the SSTT, the hydraulic umbilical is again connected with the THRT. Without the SSTT and the shear joint, the BOP shear rams would sever the hydraulic umbilical and control of the THRT would be lost. Depending on the status of the tubing hanger lockdown and release mechanisms when control is lost, this can be a very costly and time consuming problem to fix.
Wile adequate for many applications, prior art hydraulically operated THRT's have several disadvantages which have become more problematic as subsea wells are drilled in deeper and deeper waters. First, hydraulic umbilicals are subject to collapse due the extreme hydrostatic pressures experienced at great depths. This can result in a temporary or permanent loss of control of the THRT or, in the worst case, a premature release and consequent dropping of the tubing hanger and the production tubing into the well.
Second, some operators prefer to use a surface BOP and a smaller diameter high pressure riser to connect the surface vessel to the production member in deep water. In this arrangement, the hydraulic umbilical for the THRT is routed through a "slick joint" in the running string which is positioned in the surface BOP. However, this requires that the umbilical be cut to a precise length in order to properly "space out" the slick joint, and this can be a difficult and expensive undertaking.
Third, as wells are drilled in progressively deeper waters, the use of "slimbore" completion systems is becoming increasingly popular. These systems comprise production members which have relatively small drift diameters. Consequently, the tubing hangers and THRT's for such systems must have correspondingly small diameters. However, when the tubing hanger lockdown mechanism is supported on the tubing hanger and the lockdown tool is incorporated in the THRT, minimizing the diameter of these components can be a challenge.


A semiconductor apparatus is provided which makes it possible to reduce the number of control terminals required for switching through paths of a high frequency signal, simplify the circuit configuration for controlling the terminals, improve an isolation characteristic between on path and off path of a through FET, and obtain a sufficiently high isolation. In this semiconductor apparatus, one specific through FET and each of shunt FETs connected to each of through FETs other than the one specific through FET are simultaneously turned on in response to the same control signal inputted to the same control terminal. Thus, when a high frequency signal leaks from an output terminal to the signal path of the through FET having been turned on, through the signal paths of the through FETs having been turned off, the high frequency signal can be released to GND through the shunt FET having been turned on.

In recent years, as the number of cellular phone users increases, it has become difficult to secure communication lines for cellular phones of a single cellular phone system. Thus, cellular phones each of which responds to more than one cellular phone communication system are demanded on the market. Hence, a switching circuit for switching the frequencies of a number of communication systems without allowing the communication systems to affect other parts is demanded for an antenna.
In order to meet the needs of the market, in a conventional semiconductor apparatus where a switching circuit is integrated by semiconductors (for example, Japanese Patent Laid-Open No. 9-153781), shunt FETs are provided respectively for through FETs (field-effect transistor) allowing the passage of a signal and through FETs for interrupting a signal in signal paths (through). Before a desired inputted high frequency signal leaks to other parts through the interrupting through FET, the high frequency signal is released to a part not affecting the parts of other frequencies or cellular phone systems through the shunt FET allowing the passage of a signal, so that a high isolation is obtained between changeover terminals.
The conventional semiconductor apparatus with an integrated switching circuit will be discussed below in accordance with the accompanying drawings. The drawings only illustrate control signal circuits for switching signal paths by through FETs and capacitor circuits for grounding output terminals to GND in a high frequency manner. DC power supply circuits for supplying power to the FETs are omitted.
First, the following will discuss a "Single Pole Three Throw (hereinafter, referred to as SP3T) switch" having a switching function of switching three output paths for one input path.
FIG. 5 is a circuit diagram showing the configuration of a semiconductor apparatus according to conventional example 1 and is also a circuit diagram showing an SP3T switch. A method of using the SP3T switching circuit will be discussed below. In FIG. 5, reference numeral RF1 denotes an input terminal of a high frequency signal, reference numerals RF2, RF3, and RF4 denote output terminals of a high frequency signal, reference numerals 5, 6, and 7 denote gate bias terminals, reference numerals 5-a, 6-b, and 7-c denote feedthrough FETs (abbreviated as through FETs), and reference numerals 5-a_R, 6-b_R, and 7-c_R denote gate resistors. In FIG. 5, the through FETs 5-a, 6-b, and 7-c are N-type channel FETs.
Referring to FIG. 6, an operating principle of transmitting a high frequency signal (RF) from the input terminal RF1 to the output terminal RF4 will be discussed below based on a method of switching through FETs in the semiconductor apparatus of FIG. 5.
In order to turn on the FET, 0 V or a positive voltage not higher than a Schottky barrier voltage (about 0.7 V) is applied as a voltage between the gate and drain terminals and the gate and source terminals of the FET. Thus, the FET is forward biased and the channel of the FET is opened, so that an RF signal is transmitted between the input terminal RF1 and the output terminal RF4. In order to turn off the FET, a voltage between the gate and drain of the FET and a voltage between the gate and source of the FET are set to the equivalent voltage of the threshold of the FET or lower. Hence, the channel of the FET is closed and the FET is turned off.
FIG. 6 is a circuit diagram showing an operation when the semiconductor apparatus of conventional example 1 is turned on between the input terminal RF1 and the output terminal RF4. FIG. 6 shows that the gate bias terminals 5 and 6 are set to L (off) and the gate bias terminal 7 is set to H (on) in response to a control signal fed with voltage from an external power supply. Under this condition, a voltage drops on the resistor 7-c_R, so that the through FET 7-c is turned on. Hence, when the through FET 7-c is turned on, passage is enabled through a signal path between the input terminal RF1 and the output terminal RF4. Example applications for the operating principle of the SP3T switch include a Single Pole four Throw (SP4T) switch and a Single Pole five Throw (SP5T) switch.
The items of characteristic evaluation of an antenna switch using FETs include an insertion loss, an isolation, harmonics, a ratio of leakage power between adjacent channels. An insertion loss is a degree of attenuation of an RF signal passing between the source and drain of the through FET 7-c when the RF signal is transmitted from the input terminal RF1 to the output terminal RF4. An isolation is a degree of leakage of an RF signal to the other output terminals RF2 and RF3 when the RF signal is transmitted from the input terminal RF1 to the output terminal RF4. A low insertion loss and a high isolation are demanded as ideal characteristics of a switching circuit used as an antenna switch. An insertion loss and an isolation are also items of characteristic evaluation of a small signal.
On the other hand, in the switching circuit shown in FIGS. 5 and 6, only the through FETs are present on the signal paths. Thus, an insertion loss increases at a specific frequency of a high frequency signal transmitted to each of the signal paths and an isolation deteriorates between the on path and the off path of the through FET.
In order to prevent these problems, the shunt FET is arranged between the output terminal and the through FET on the signal path. A unit for particularly reducing an insertion loss and improving an isolation will be discussed below in accordance with an illustration of SP3T.
FIG. 7 is a circuit diagram showing the configuration of a semiconductor apparatus of conventional example 2 and is also a circuit diagram showing SP3T type switches constituting shunt FETs near output terminals RF2, RF3, and RF4. The shunt FETs are configured near the output terminals, respectively. Referring to FIG. 8, the following will particularly describe a switching principle allowing passage between an input terminal RF1 and the output terminal RF4 when the SP3T type switching circuit of FIG. 7 is operated.
A through FET 7-c on ON path between the input terminal RF1 and the output terminal RF4 is turned on, and a shunt FET 5-c between the output terminal RF4 and a capacitor C10 having one terminal connected to GND 10 is turned off. On OFF path between the input terminal RF1 and the output terminal RF2 and between the input terminal RF1 and the output terminal RF3, a through FET 5-a and a through FET 6-b on OFF path are turned off, and a shunt FET 6-a between the output terminal RF2 and a capacitor C8 having one terminal connected to GND 8 and a shunt FET 7-b between the output terminal RF3 and a capacitor C9 having one terminal connected to GND 9 are turned on. Consequently, an RF signal is transmitted from the input terminal RF1 to the output terminal RF4 and an RF signal transmitted to the OFF path is grounded to the GND 8 and GND 9 through the capacitor C8 and the capacitor C9, thereby reducing the leakage of the RF signal to the output terminal of the OFF path.
However, as shown in FIGS. 7 and 8, the semiconductor apparatus where the conventional switching circuit is formed requires six voltage control terminals for controlling on/off of the FETs on the three paths and the shunt FETs connected to the FETs, for example, in the SP3T, resulting in a complicated circuit configuration for controlling the switching operation of the semiconductor apparatus having such a switching function.
In other words, when the switching circuit principle illustrated in FIG. 8 is used based on the configuration of FIG. 7, the terminals for controlling the FETs have to operate separately, and thus control terminals 5′, 6′ and 7′ for the shunt FETs are necessary in addition to the control terminals 5, 6, and 7 for the feedthrough FETs. Thus, six control terminals are necessary in total. Alternatively, Logic for controlling terminals in a complicated configuration has to be used to reduce the number of times of control on the control terminals.
The present invention is devised to solve the problem and provides a semiconductor apparatus which makes it possible to reduce the number of control terminals required for switching the through paths of a high frequency signal, simplify the circuit configuration for controlling the terminals, improve an isolation characteristic between the on path and off path of the through FET, and obtain a sufficiently high isolation.

Semiconductor switching circuit for switching the paths of a high frequency signal in a mobile communications unit

Matsushita Electric Industrial Co., Ltd.


An ink supply structure for supplying ink flowing out from an ink cartridge including an ink supply port via an ink transporting tube to a recording portion, including: an ink cartridge base having; a cartridge connecting portion which makes the ink flowing out from the ink cartridge, when the cartridge connecting portion connects to the ink supply port upon loading of the ink cartridge on the ink cartridge base; an ink flow path which connects to the cartridge connecting portion; and a tube connecting portion connected to the ink transporting tube, wherein the ink cartridge base is configured by a base main body and a supplemental member fitted in the base main body, and wherein the ink flow path is formed on joint faces between the base main body and the supplemental member.

1. Field
Aspects of the present invention relate to a multi-function device, printer and an ink supply structure for use in the multi-function device and the printer to supply ink from an ink cartridge to a recoding portion.
2. Description of the Related Art
Conventionally, known ink cartridges are separately disposed from ink jet heads. If the ink cartridge is disposed on an ink jet head, the ink printer may be required to be taller than desired to accommodate the ink cartridge. In an example of an ink-jet printer, an ink cartridge holder is disposed on a front-left side portion of the printer main body. The ink cartridge holder is opened forwardly from the opening to house the ink cartridge. Further, a rod-like ink outlet port connectable to an ink cartridge is disposed at a back-face wall of the ink cartridge holder. A tube path connecting the inkjet head and the ink outlet port is disposed on a back side of the back-face wall.
A space exclusively used for the tube path is necessary for the above-configuration. This prevents the printer's size from being reduced.

Ink supply structure with transport tube


A field emitter including an exposed wide band gap emission area in contact with and protruding from a planar surface of a conductive metal, and a method of making is disclosed. Suitable wide band gap materials (2.5-7.0 electron-volts) include diamond, aluminum-nitride and gallium-nitride; suitable conductive metals include titanium, tungsten, gold and graphite. The method includes disposing the wide band gap material on a substrate, disposing the conductive metal on the wide band gap material, and etching the conductive metal to expose wide band gap emission areas. The emission areas are well suited for large area flat panel displays.

1. Field of the Invention
The invention relates to field emitters, and more particularly to exposed wide band gap field emission areas and a method of making same.
2. Description of Related Art
Field emitters are widely used as sources of electrons in lamps and scanning electron microscopes since emission is affected by the adsorbed materials. Field emitters have also been found useful in flat panel displays and vacuum microelectronics applications. Cold cathode and field emission based flat panel displays have several advantages over other types of flat panel displays, including low power dissipation, high intensity and low projected cost. Thus, an improved field emitter and any process which reduces the complexity of fabricating field emitters is clearly useful.
The present invention can be better appreciated with an understanding of the related physics. General electron emission can be analogized to the ionization of a free atom. Prior to ionization, the energy of electrons in an atom is lower than electrons at rest in a vacuum. In order to ionize the atom, energy must be supplied to the electrons in the atom. That is, the atom fails to spontaneously emit electrons unless the electrons are provided with energy greater than or equal to the electrons at rest in the vacuum. Energy can be provided by numerous means, such as by heat or irradiation with light. When sufficient energy is imparted to the atom, ionization occurs and the atom releases one or more electrons.
Several types of electron emission are known. Thermionic emission involves an electrically charged particle emitted by an incandescent substance (as in a vacuum tube or incandescent light bulb). Photoemission releases electrons from a material by means of energy supplied by incidence of radiation, especially light. Secondary emission occurs by bombardment of a substance with charged particles such as electrons or ions. Electron injection involves the emission from one solid to another. Finally, field emission refers to the emission of electrons due to an electric field.
In field emission (or cold emission), electrons under the influence of a strong electric field are liberated out of a substance (usually a metal or semiconductor) into a dielectric (usually a vacuum). The electrons "tunnel" through a potential barrier instead of escaping "over" it as in thermionics or photoemission. Field emission is therefore a quantum-mechanics phenomena with no classical analog. A more detailed discussion of the physics of field emission can be found in U.S. Pat. No. 4,663,559 to Christensen; Cade and Lee, "Vacuum Microelectronics", GEC J. Res. Inc., Marconi Rev., 7(3), 129 (1990); and Cutler and Tsong, Field Emission and Related Topics (1978).
The shape of a field emitter affects its emission characteristics. Field emission is most easily obtained from sharply pointed needles or tips whose ends have been smoothed into a nearly hemispherical shape by heating. Tip radii as small as 100 nanometers have been reported. As an electric field is applied, the electric lines of force diverge radially from the tip and the emitted electron trajectories initially follow these lines of force. Field emitters with such sharp features similar to a "Spindt cathode" have been previously invented. An overview of vacuum electronics and Spindt type cathodes is found in the November and December, 1989 issues of IEEE Transactions of Electronic Devices. Fabrication of such fine tips, however, normally requires extensive fabrication facilities to finely tailor the emitter into a conical shape. Further, it is difficult to build large area field emitters since the cone size is limited by the lithographic equipment. It is also difficult to perform fine feature lithography on large area substrates as required by flat panel display type applications. Thus, there is a need for a method of making field emitters with fine conical or pyramid shaped features without the use of lithography.
The work function of the electron emitting surface or tip of a field emitter also effects emission characteristics. The work function is defined as the difference in energies of the Fermi level and vacuum level. A smaller work function requires lower voltage to emit electrons from a surface. In a metal, the Fermi level is the same as the conduction band. In wide band gap materials, however, the Fermi level lies between the conduction band and the valence band. In such a case, the work function of the material changes as the Fermi level changes due to doping or defects. Further, the energy difference between the conduction band and vacuum level is a fundamental material property referred to as electron affinity. Thus, the work function and electron affinity are the same in a metal, but different in a wide band gap material. Recently, several wide band gap semiconductors (insulators at room temperature) such as diamond and aluminum-nitride have been shown to have negative electron affinity as well. See, for example, Yoder, "Applications of Diamond and Related Materials", 5th Annual Diamond Technology Workshop, Troy, Mich., May 18-20, 1994; Davis, "Growth and Characterization of III-V Nitride Thin Films via Plasma-and Ion-assisted Gas-source Molecular Beam Epitaxy", 5th Annual Diamond Technology Workshop, Troy, Mich., May 18-20, 1994; Rubin et al., "P-Type Gallium Nitride by Reactive Ion-Beam Molecular Beam Epitaxy with Ion Implantation, Diffusion or Coevaporation of Mg", pre-print by Lawrence Berkeley Laboratory, University of California, Berkeley, Calif., March 1994, pp. 1-7; and Newman et al., "Thermodynamic and Kinetic Processes Involved in the Growth of Epitaxial GaN Thin Films", Applied Physics Letters, 62 (11), 15 Mar. 1993, pp. 1242-1244.
There are other materials which exhibit low or negative electron affinity, but almost all of these materials are alkali metal based. Alkali metals are quite sensitive to atmospheric conditions and tend to decompose when exposed to air or moisture. Additionally, alkali metals have low melting points, typically below 1000.degree. C., which may be unsuitable in certain applications.
For a full understanding of the prior art related to the present invention, certain attributes of diamond must also be discussed. Recently, it has been experimentally confirmed that the (111) surface of diamond crystal has an electron affinity of -0.7+/-0.5 electron-volts, showing it to possess negative electron affinity. A common conception about diamonds is that they are very expensive to fabricate. This is not always the case, however. Newly invented plasma chemical vapor deposition processes appear to be promising ways to brig down the cost of producing high quality diamond thin films. For instance, high fidelity audio speakers with diamond thin films as vibrating cones are already commercially available. It should also be noted that diamond thin films cost far less than the high quality diamonds used in jewelry.
Diamond cold cathodes have been reported by Geis et al. in "Diamond Cold Cathode", IEEE Electron Device Letters, Vol. 12, No. 8, Aug. 1991, pp. 456-459; and in "Diamond Cold Cathodes", Applications of Diamond Films and Related Materials, Tzeng et al. (Editors), Elsevier Science Publishers B.V., 1991, pp. 309-310. The diamond cold cathodes are formed by fabricating mesa-etched diodes using carbon ion implantation into p-type diamond substrates. Geis et al. indicate that the diamond can be doped either n- or p-type. In fact, several methods show promise for fabricating n-type diamond, such as bombarding the film with sodium, nitrogen or lithium during growth. However, in current practice it is extremely difficult to fabricate n-type diamond and efforts for n-type doping usually result in p-type diamond. Furthermore, p-type doping fails to take full advantage of the negative electron affinity effect, and pure or undoped diamond is insulating and normally charges up to prevent emission.
There exists a need for improved methods of making field emission areas as well as improved field emitter structures using diamond and other wide band gap materials.

Field emitter with wide band gap emission areas and method of using


A signal receiver includes a data sampler receiving a differential input signal having first and second input signals and determining bit values of the differential input signal based on first and second reference voltages, and a reference voltage generator performing a pre-tuning operation and a post-tuning operation to generate the reference voltages. The reference voltage generator performs the pre-tuning operation by generating first and second initial voltages and adjusting one of the initial voltages to generate third and fourth voltages. After the pre-tuning operation, the reference voltage generator performs the post-tuning operation by increasing or decreasing the third voltage to generate the first reference voltage and decreasing or increasing the fourth voltage to generate the second reference voltage based on a comparison result between the third voltage and the first input signal and a second comparison result between the fourth voltage and second input signal.

Embodiments of the inventive concept disclosed herein relate to an electronic device, and more particularly, relate to a signal receiver and an operation method thereof.
An electronic device includes various function blocks or devices configured to provide various functions. To provide various functions, various function blocks or devices may exchange data. In general, data transmission between those function blocks or devices is performed by using a modulation scheme to transmit one bit during one unit interval (UI) like a non-return to zero (NRZ) scheme.
As performance of an electronic device is improved, a high communication speed may be desirable between function blocks or devices. To this end, a modulation scheme (e.g., PAM-4) may be used to transmit a plurality of bits (e.g., two bits) during one unit interval. In the PAM-4 scheme, a signal receiver determines bit values of an input signal received by using a plurality of reference voltages (e.g., three reference voltages) determined in advance. However, in the case where distortion occurs in an input signal, bit values are not properly determined through the reference voltages.

Signal receiver and operation method thereof


An image forming apparatus including an image forming unit and a controller causing the image forming unit to perform printing in printing periods after respective non-printing periods occurring alternately with the printing periods, determining a number of sheets to be printed in each of the printing periods in accordance with a number of sheets remaining to be printed in a print job, wherein, when printing periods include a first printing period and a second printing period, determining a number of sheets to be printed in the first printing period and determining a number of sheets to be printed in the second printing period which is in relation to the determined number of sheets to be printed in the first printing period, and determining a length of each of the non-printing periods in accordance with the determined number of sheets to be printed in each of the printing periods.

A known image forming apparatus performs intermittent printing in which a printing period during which printing is performed and a non-printing period during which printing is not performed are alternately repeated. The non-printing period, which is a certain time period for not performing printing, is provided after a printing period during which a predetermined number of sheets are printed successively. This arrangement enables, for example, restriction of increase in the internal temperature of the image forming apparatus.
The known image forming apparatus performs a printing operation in one of a continuous operation mode and an intermittent operation mode. When the internal temperature of the image forming apparatus reaches a specified temperature, the image forming apparatus changes its operating mode from the continuous operation mode to the intermittent operation mode.

Image forming apparatus, non-transitory computer-readable storage medium storing computer-readable instructions, and printing apparatus


A packaging machine moves its heater unit for longitudinal sealing of a tubularly formed film between a sealing position at which the heater unit contacts the film and a retracted position at which it is separated from the film. In addition to the mechanism for this motion, an air cylinder is provided for controlling the compressive force with which the heater unit at its sealing position compresses the film. A pressure controlling system regulates the air pressure supplied to the air cylinder. If the mechanism for moving the heater unit also employs another air cylinder, a higher pressure for moving the heater unit and a lower pressure for controlling its compressive force may be generated from a single air source and supplied to the two air cylinders by a switching mechanism. A single air cylinder with two air chambers may be used for the both functions. A motor is additionally provided for removing the heater unit and its support unit much farther away from the film to provide a large enough space for exchanging the former and/or the chute of the packaging machine.

This invention relates to a method of using a form-fill-seal packaging machine for forming bags while concurrently filling and sealing them with articles to be packaged and more particularly to a method of longitudinally sealing a tubularly formed bag-making material to form a bag by using such a bag-making material.
In general, a packaging machine of this type is structured so as to bend an elongated web of thermoplastic bag-making material (herein referred to as the "film") into a tubular form around a chute through which articles are dropped to be packaged, to longitudinally seal its mutually overlapping side edges by means of a longitudinal sealer and then to seal the tubularly formed film transversely to produce a packaged product.
The aforementioned process of longitudinal sealing is usually effected by causing a heated heater block to intermittently come into contact with the chute so as to sandwich and compress the overlapped edge parts of the film between the block and the outer front surface of the chute while the film is being transported longitudinally (the intermittent mode of film transportation) or by leaving a heated metallic heater belt in contact with the chute such that the overlapped edge parts of the film is continuously pressed against each other between the block and the chute (the continuous mode of film transportation). In what follows, such a heater block and a heater belt will be both referred to as the "heater" and discussed together for convenience.
In either mode of transportation described above, the heater is adapted to move between a sealing position where the heater comes into contact with the chute to effect the longitudinal sealing and a retracted position to which the heater is moved away from the chute. In the intermittent mode of transportation, the heater is moved to a retracted position while the film is being transported. In the continuous mode of transportation, on the other hand, the heater is moved to the retracted position when, for example, a trouble has occurred and the transportation of the film is interrupted temporarily in order to prevent the overheating of the film.
While the heater is at the sealing position, it presses the film against the chute with a specified pressure for the thermal sealing. This compressive pressure is usually supplied by the biasing force of a spring, and it has been the practice to adjust its compressive force. It sometimes happens when the chute is attached to the main frame of the packaging machine, however, that the chute is not exactly at the intended position, depending on the manner in which the attachment is effected, or that the relative position changes or the shape of the heater changes after many years of use. In such a situation, the sealing position of the heater may change and the compressive force by the spring may also change. Thus, the compressive force of the spring had to be adjusted as the sealing position of the heater changed.
Manual adjustment of the spring could not be done very accurately. Moreover, the recent trend is that the compressive force of the spring must be adjusted not only according to the film characteristics such as its thickness and material but also according to the method of sealing such as the so-called lap sealing and fin sealing and also according to the operational capabilities and conditions. In other words, fine adjustments of the compressive force of the spring according to many factors are now a commonly required procedure.
As explained above, furthermore, the heater must generally be moved between a sealing position and a retracted position. A quick response is required in this motion such that the heater can move between these positions as instantaneously as possible. This means that a fairly large force is necessary for the motion of the heater and further that a different kind of improved control is necessary. Thus, there is now a new problem of how to control these two kinds of forces on the single heater.

Method of longitudinally sealing tubular bag-making material


A flexible medical closure screen for closing a separation of first and second tissue portions is provided, which includes a mesh screen comprising tubular vertical risers, vertical strands with barbed filaments, and horizontal spacers connecting the risers and strands in a grid-like configuration. An optional perimeter member partly surrounds the screen and can comprise a perimeter tube fluidically coupled with the vertical risers to form a tubing assembly. Various input/output devices can optionally be connected to the perimeter tube ends for irrigating and/or draining the separation according to methodologies of the present invention. Separation closure, irrigation and drainage methodologies are disclosed utilizing various combinations of closure screens, tubing, sutures, fluid transfer elements and gradient force sources. The use of mechanical forces associated with barbed strands for repositionably securing separated tissues together is disclosed. The use of same for eliminating or reducing the formation of subcutaneous voids or pockets, which can potentially form hematoma and seroma effects, is also disclosed. Alternative embodiment flexible closure screens and methods of using same are also disclosed.

1. Field of the Invention
The present invention relates generally to medical (including dental, veterinary, etc.) closure and wound fluid management devices, and in particular to a flexible medical closure screen for closing tissue separations, such as incisions and wounds, which closure member is optionally bioabsorbable. The closure member can be assembled with different components chosen for their functional and material compatibility characteristics.
2. Description of the Prior Art
In the medical field, which is broadly defined to include dentistry, veterinary medicine, etc., cutaneous incisions are commonly performed in surgery to provide access to underlying tissue, organs, joints, skeletal structure, etc. Incision and closure techniques are an important part of surgery in general. They tend to occupy surgical teams and other resources for significant portions of many surgical procedures.
Surgeons generally strive to minimize the traumatic and scarring effects of surgery on their patients by both minimizing the incisions, and by employing a variety of closure techniques which tend to reduce postoperative swelling, bleeding, seroma, infection and other undesirable postoperative side effects. For example, the fields of endoscopic-assisted surgery, microscopic surgery, and computer-enhanced instrumentation (e.g., the DaVinci System available from Intuitive Surgical, Inc. of Sunnyvale, Calif.) are generally concerned with minimally invasive surgery ("MIS") procedures and techniques, which have proven to be increasingly popular. Such popularity is at least partly due not only to the minimally-sized scars left by such techniques, but also to the minimal trauma to the fascia and muscle layers and the correspondingly faster recoveries this allows. However, surgeons must balance such considerations with providing adequate access to perform various surgical procedures. A typical surgical procedure involves a cutting or dissecting phase and a closing phase. In recent years, considerable progress has been made in minimizing surgical cutting, dissecting and shaping. Surgical closing techniques involve sutures, clips, staples and adhesives. However, suturing can be time-consuming and tedious. Moreover, the tissue structures to be joined may not be amenable to other closure techniques. MIS often restricts access to the separated tissue structures, thus making it more difficult to approximate and close same.
In contrast to MIS, some surgical procedures, by their nature, must include long incisions. Examples include cutaneous excisional procedures such as "lifts" and reduction procedures, flap procedures for closure of defects, and many bariatric procedures. Suturing in these extensive defects can be time-consuming and tedious.
The "first intention" (primary intention healing) in surgery is to "close" the incision. For load-bearing tissues, such as bone, fascia, and muscle, this requires substantial material, be it suture material, staples, or plates and screws. For the wound to be "closed," the epithelial layer must seal. To accomplish this, the "load bearing" areas of the cutaneous and subcutaneous layers (i.e., the deep dermal elastic layer and the superficial fascia or fibrous layers of the adipose tissue, respectively) must also at least be held in approximation. Important considerations include controlling infection and bleeding, reducing scarring, eliminating the potential of hematoma, seroma, and "dead-space" formation and managing pain. Dead space problems are more apt to occur in the subcutaneous closure. Relatively shallow incisions can normally be closed with surface-applied closure techniques, such as sutures, staples, glues, and adhesive tape strips. However, deeper incisions may well require not only skin surface closure, but also time-consuming placement of multiple layers of sutures in the load-bearing planes. Absorbable sutures are commonly used for this purpose and comprise an important class of surgical sutures. Depending on various factors, absorbable sutures typically dissolve over a period of a few days to a few months. Commercially available examples include Monocryl® monofilament absorbable synthetic sutures comprising a poliglecaprone and PDS® (polydrioxanone) and Vicryl® (polyglactin) sutures, all available from Ethicon, Inc., of Somerville, N.J.
Surgical mesh is commonly used to span or reinforce load-bearing planes or defects in them. When coupled with sutures or fasteners, surgical mesh represents another important class of surgical closure devices. Applications include reconstruction, hernia repair, and organ repair. In such procedures, surgical mesh fabric prostheses are inserted into patients through either open surgery or endoscopic (MIS) procedures. Knitted surgical mesh for hernia repair is disclosed in the Agarwal et al. U.S. Pat. No. 6,287,316, which is assigned to Ethicon, Inc. Another Ethicon, Inc. patent, Duncan U.S. Pat. No. 4,548,202, discloses mesh tissue fasteners including various fastening members with spaced-apart legs for passing through tissue portions. Another closure procedure involves the placement of pins or rods through skin edge or bone followed by the placement of an external clamp or fixator device spanning the wound and frequently incorporating a worm-screw apparatus capable of progressive tightening over time to effect closure, stabilization or distraction.
Fluid management represents another important aspect of both open and minimally invasive surgery. Postoperative fluid drainage can be accomplished with various combinations of tubes, sponges, and porous materials adapted for gathering and draining bodily fluids. The prior art includes technologies and methodologies for assisting drainage. For example, the Zamierowski U.S. Pat. Nos. 4,969,880; No. 5,100,396; No. 5,261,893; No. 5,527,293; and No. 6,071,267 disclose the use of pressure gradients, i.e., vacuum and positive pressure, to assist with fluid drainage from wounds including surgical incision sites. Such pressure gradients can be established by applying porous foam material either internally or externally to a wound, covering same with a permeable, semi-permeable, or impervious membrane, and connecting a suction vacuum source thereto. Fluid drawn from the patient is collected for disposal. Such fluid control methodologies have been shown to achieve significant improvements in patient healing. Another aspect of fluid management, postoperative and otherwise, relates to the application of fluids to wound sites for purposes of irrigation, infection control, pain control, growth factor application, etc. Wound drainage devices are also used to achieve fixation and immobility of the tissues, thus aiding healing and closure. This can be accomplished by both internal closed wound drainage and external vacuum devices. Fixation of tissues in apposition can also be achieved by bolus tie-over dressings (Stent dressings), taping, strapping and (contact) casting.
Heretofore, there has not been available a flexible medical closure screen and method with the advantages and features of the present invention, including the combination of same with negative pressure wound therapy ("NPWT").

Flexible medical closure screen and method


The present invention relates to pyridazinone compounds and their derivatives according to the general formula (I), with the substituents X, R1 and R2 defined herein, as well as their physiologically acceptable salts, methods for producing these compounds and their use as pharmaceuticals.

The present invention relates to compounds according to the general formula (I), with the definitions of the substituents X, R1 and R2 given below in the text, as well as their physiologically acceptable salts, methods for producing these compounds and their therapeutic use as pharmaceuticals.
These compounds are known as kinase inhibitors, and in particular, inhibitors of the glycogen synthase kinase-3β (kinase GSK-3β)
It is known from the literature that in the case of metabolic diseases such as diabetes or neurodegenerative diseases such as Alzheimer's disease and multiple sclerosis, there is a connection between the therapy of said diseases and the inhibition of GSK-3β or the phosphorylation of the tau-protein (S. E. Nikoulina. Diabetes 51, 2190-2198, 2002; Henrikson. Am. J. Physiol. 284, E892-900, 2003). There are a number of compounds and pharmaceuticals that are already employed in the treatment of said diseases, in which the compounds interfere at different places within the biochemical processes that causes the respective disease. However, there is only a very limited number of compounds known until now, which effectively inhibit glycogen synthase kinase GSK-3β.
WO 04/046117 discloses a number of pyridazinone derivatives, which can be employed for the inhibition of GSK-3β. They differ from the compounds of the present invention in the substitution of the pyridazinone cycle, since at position 4 of the ring there is an amido group substituent instead of a heteroaryl substituent such as pyrrole or indole.
International Application PCT-EP 05/002179 also discloses pyridazinone derivatives that are useful in the inhibition of GSK-3β. In contrast to the compounds of the present invention, those compounds are substituted at position 4 of the pyridazinone cycle by a benzimidazole group. U.S. Patent Appln. 2002/0119963 to Sanner et. al. discloses imidazole derivatives having activity for inhibiting the kinases CDK5, CDK2 and GSK-3. The imidazole derivatives are substituted via the first nitrogen atom, among others, with a 3-8-membered hydrocyclelalkyl or a 5-14-membered hydroaryl group, but a pyridazinone group is not explicitly disclosed therein. Additionally, the imidazole derivative is substituted with an amino group, which is further substituted with a carboxyl group. Therefore, it is evident, that the pyridazinone derivatives of the present invention are not disclosed by U.S. Patent Appln. No 2002/0119963 to Sanner et. al. Compounds as those explicitly disclosed by US-A 2002/0119963 are not a subject of the present invention.
Furthermore, there are many pyridazinone derivatives described in literature, which differ from those of the present invention due to a different substitution pattern within the molecule and (partially) different indications.
WO 03/059891 discloses pyridazinone derivatives that are useful for treating diseases and conditions caused or exacerbated by unregulated p 38 MAP Kinase activity and/or TNF activity. The compounds described therein can be used, for example, for the treatment of inflammatory conditions, diabetes, Alzheimer's disease or cancer. They differ from the compounds of the present invention in the substitution of the pyridazinone cycle, since the nitrogen at position 2 of the cycle is mostly substituted with alky, aryl or heteroaryl and at position 4 of the cycle there is no heteroaryl group (such as pyrrole or indole) defined as substituent.
JP-A 09 216883 discloses pyridazinone derivatives which can be used to treat heart failure or high blood pressure. The pyridazinone derivatives described therein obligatorily have a pyrazolo[1,5-a]pyridine substituent in position 6, which is in turn substituted in position 2 by aryl, preferably phenyl. The pyridazinone ring itself is additionally substituted in position 2 by substituents such as hydrogen, lower alkyl or a heterocycle, while position 4 has substituents such as hydrogen, acyl, cyano, Heterocyclyl such as tetrazolyl, amino or a protected amino group. Where the substituent in position 4 is a heterocycle, it preferably has 3 to 8 ring members and is saturated. However, a heterocyclic group is not included in the preferred substituents in position 4 of the pyridazinone ring of the compounds disclosed in this document. Compounds as such explicitly disclosed in JP-A 09 215883 are no subject of the present invention.
Bicyclic heterocycles, having an inhibiting effect on aggregation, are described in EP-A 0 639 575. Therein, it is a general formula (I) disclosed having a bicyclus containing the substituent A, from which an indole-derivative can be derived having at least one additional nitrogen atom in the cycle which contains the substituent A. Furthermore, a pyridazinone derivative can theoretically be derived from the substituent B having in turn a multimembered substituent, which mandatorily contains a 1,4-cyclohexylen or 1,4-cyclohex-3-enylen group and a carbonyl group. Therefore, it is evident, that the compounds of the present invention are not disclosed by EP-A 0 639 575. Compounds such as explicitly disclosed by EP-A 0 639 575 are no subject of the present invention.
The documents EP-A 075 436, U.S. Pat. No. 4,734,415 and U.S. Pat. No. 4,353,905, both to Sircar et. al. describe pyridazinone derivatives as antihypertensive agents and as agents which increase cardiac contractibility. These pyridazinone derivatives have a phenyl residue at position 6 of the pyridazinone cycle, said phenyl residue is additionally substituted with a heterocycle containing at least one nitrogen atom. Whereas the pyridazinone derivatives described in the documents EP-A 075 436 and U.S. Pat. No. 4,353,905 do not have a substituent at position 4 of the pyridazinone cycle, those disclosed in U.S. Pat. No. 4,734,415 may have an amido group substituted with lower alkyl at this position. Compounds as such, explicitly disclosed by Sircar et. al. '415 are also not a subject of the present invention.
Thus, there exists a strong need for compounds that have an affinity for and have an inhibitory effect for GSK-3β and/or the phosphorylation of the tau-protein. The object of the present invention is to provide compounds that exhibit this ability.

This patent is subject to a terminal disclaimer.

Pyridazinone derivatives, methods for their production and their use as pharmaceuticals

Abstract: These compounds are kinase inhibitors, in particular inhibitors of the kinase GSK-3β (glycogen synthase kinase-3β) which are useful in the treatment of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, strokes, cranial and spinal traumas and peripheral neuropathies, obesity, metabolic diseases, type II diabetes, essential hypertension, atherosclerotic cardiovascular diseases, polycystic ovary syndrome and syndrome X or immunodeficiency.


A method for storing data. The method includes providing an addressable memory including a memory space, wherein the memory space includes a plurality of memory cells. The method includes configuring the addressable memory such that a majority of the plurality of memory cells in the memory space stores internal data values in a preferred bias condition when a first external data state of one or more external data states is written to the memory space, wherein the first external data state is opposite the preferred bias condition.

Semiconductor memory devices, such as dynamic random access memories (DRAMs) are included in an array of programmable memory cells for purposes of storing and accessing data. The DRAM cell includes a field effect transistor (FET) and a storage capacitor. Information is stored on the capacitor either in a charged state or discharged state. The FET provides access to the capacitor during read and write operations. Additionally, the DRAM cell periodically is refreshed to retain the proper state, because of potential leakage in the capacitor.
The configuration of a DRAM memory array is typically robust, and is capable of being accessed for read, write, and refresh operations with very low error rates. However, a memory cell is susceptible to various types of errors that may not be shown as a defect in the cell, but are due to factors that influence the memory cell at one particular time. As such, the state of a memory cell may be affected by noise, soft error rates, leakage, and other factors that may result in data loss.
For instance, non-defect related errors, including soft errors, are due to electrical, magnetic, or other interferences affecting the memory cell. These errors may be due to internal or external generation of noise and/or radiation. For instance, these errors may be due to background radiation generated from a material decay in a chip resulting in stray alpha particles randomly hitting a memory cell, or cosmic radiation (e.g., noise) due to very high energy particles originating from outer space that are hitting memory cells in an array. Also, with higher densities of cells in a memory array, the possibility of noise related disturbs of individual memory cells increases. More particularly, these random electrical occurrences may affect the stored charge on the capacitor of the DRAM memory cell, and cause the memory cell to change state. As such, these errors may not necessarily be due to a defect in the cell construction, however, the information stored on the DRAM memory cell may be incorrect.
On the one hand, because the data loss due to non-defect related errors is not fatal to the memory, the memory cell may be corrected to properly store the valid state of the memory cell after the error is discovered. However, the ability to correct comes with the added penalty of increased circuit complexity, increased chip size, increased power usage, and/or reduced access time. On the other hand, the data loss may result in improper execution of an application or a system crash, since it may change an instruction or data value. In that case, although the memory system is fully functional, the underlying application and/or data has been damaged and may require correction of the states of the affected memory cells. For instance, the affected memory cells may be rewritten (e.g., through error detection and correction techniques), or the system may be rebooted in order to resuscitate a crashed application by repopulating the information in the memory array.
Also, latent defects may adversely affect a memory cell by increasing the rate of signal loss and increasing the probability of soft errors. For instance, one or more latent defects may weaken a memory cell over time, bringing that cell closer to a point of failure. A cell with a latent defect may operate on the margins of failure and not fail under normal operating conditions. However, that cell, when compared to stronger cells without latent defects, may be more prone to soft errors when exposed to the previously discussed interferences (e.g., electrical, magnetic, etc.).
It is desirous to provide a memory array that is less susceptible to non-defect errors, such as, noise, soft errors, etc.

Retention optimized memory device using predictive data inversion


A multi-strobe apparatus for generating multi-strobe having a plurality of strobes is provided, wherein the multi-strobe apparatus includes a clock generating unit which is able to generate a signal for adjustment at a timing at which each of the plurality of strobes should be generated; a strobe generating circuit for generating the plurality of strobes; and an adjusting module for adjusting a timing of the strobe generating circuit's generating each of the strobes on the basis of the signal for adjustment.

1. Field of the Invention
The present invention relates to a multi-strobe apparatus for generating multi-strobe having a plurality of strobes, a testing apparatus for testing an electronic device, and an adjusting method for adjusting a timing of generating a strobe of each strobe of the multi-strobe. More particularly, the present invention relates to a multi-strobe apparatus for controlling a timing of generating each strobe.
2. Description of Related Art
Conventionally, in case of detecting a variation point of a value of a signal to be measured, one strobe is delayed at every cycle of the signal to be measured and is output, the value of the signal to be measured is detected for each strobe, and variation in the value is detected. This method is used to detect a variation point of the value of each of a data signal and a DSQ signal, etc. for a memory setup/hold testing, for example.
A device of double data rate type which outputs a data signal synchronously with a rising or a falling of a clock (DQS) like DDR-SDRAM (Double Data Rate-SDRAM), for example, makes the data signal follow up the clock for every predetermined width of the output data and outputs the data signal. Thus, a timing condition of setup/hold for data transfer is relieved. This kind of device is required to have a predetermined setup time and a predetermined hold time between the data signal and the clock in order to perform reset/hold of data without fault.
Conventionally, each of the values of the data signal and the clock is detected by one strobe and a variation point of each value is detected. Then, pass/fail of a device under test ("DUT") is determined according to whether or not the detected variation point satisfies the predetermined setup time and the predetermined hold time.
However, since each of the values of the data signal and the DSQ is detected at every cycle of each signal by one strobe, it is impossible to perform the testing accurately in case a jitter is generated in the data signal and the DSQ due to various causes such as power supply variation and heat variation of the device. Further, since the data signal and the DSQ are scanned by one strobe, it takes much time to perform the testing.
Accordingly, it is an object of the present invention to provide a multi-strobe apparatus, a testing apparatus, and an adjusting method, which are capable of overcoming the above drawbacks accompanying the conventional art. The above object can be achieved by combinations described in the independent claims. The dependent claims define further advantageous and exemplary combinations of the present invention.

Multi-strobe apparatus, testing apparatus, and adjusting method


An image processing apparatus is disclosed, including a modification part, a model creation part, and a division part. The modification part instructs modification of a portion of a foreground area or a background area which is erroneously divided as a result of dividing predetermined image data into the foreground area being an extraction target and the background area being an out-of-extraction target. The model creation part creates a foreground model of the foreground area and a background model of the background area which are modified, based on first pixel values of a predetermined line segment where the modification is instructed and second pixel values of the foreground area and the background area which are divided. The division part divides the image data into the foreground area and the background area by using the foreground model and the background model which are created by the model creation part.

There is a technology for automatically identifying a target (or an area) which a user desires to extract from image data. In this technology, in order to instruct a system what portion a user desires to extract as the target (or the area), a certain amount of labeling is manually conducted as initial values by the user, and then, the system automatically divides remaining portions by using the initial values. When the automatic dividing result includes an error, the system automatically re-divides the remaining portions, again (for example, see Patent Document 1 and Non-Patent Document 1).
FIG. 1A through FIG. 1E are diagrams for explaining a related art example. As illustrated in FIG. 1A, when the user encloses an extraction target by a frame 401, the system samples pixel value data 402 of a foreground from the entire inside area indicated by the frame 401, and creates a distribution model of the pixel value data 402 of the foreground in a Red, Green, and Blue (RGB) color space. Moreover, the system samples pixel value data 403 of a background from the entire outside area of the frame 401, and creates a distribution model of the pixel value data 403 of the background. The foreground or the background is determined based on whether an area is desired to be extracted, but is not determined based on a positional relationship.
After that, the foreground and the background are automatically divided by using distribution models of the foreground and the background which are created by the system. However, it is difficult to automatically and completely divide the foreground and the background in the above described technology. As illustrated in FIG. 1C, for example, an automatic division may easily cause an error for areas 406 and 407 where pixel values are close to each other, regarding a foreground area 404 of a front tomato and a background area 405 of a rear tomato. The area 406 is an area of the background erroneously divided as the foreground, and the area 407 is another an area of the foreground erroneously divided as the background.
As illustrated in FIG. 1D, the user modifies an area. A foreground marker 407a (which may be a white marker) is input to the area 407 erroneously divided as the background, and a background marker 406a (which may be a black marker) is input to the area 406 erroneously divided as the foreground. Since the automatic division is conducted again from the distribution models later, it is not required to completely modify a wrong area. By simply applying a modification marker to a portion of the wrong area, a marked area is expanded to modify the wrong area. The system samples the pixel value data from the foreground marker 407a and the foreground area 404 which is automatically divided. As illustrated in FIG. 1B, the system re-creates a distribution model 408 of pixels of the foreground in the RGB color space. Also, the system samples the pixel value data from the background marker 406a and the background area 405 which is automatically divided, and re-creates distribution models 409 of pixels of the background. Then, by using the distribution models 408 and 409 with respect to the foreground and the background which are re-created by the system and an algorithm for minimizing energy of a graph structure, as illustrated in FIG. 1E, the foreground and the background are automatically re-divided. In a case in which an error 410 still remains in a result from automatically re-dividing, a modification process from an operation depicted in FIG. 1D is repeated until there is a result in which the user satisfaction is acquired.    Patent Document 1: Japanese National Publication of International Patent Application No. 2009-545052    Non-Patent Document 1: C. Rother, V. Kolmogorv, A. Blake, "Interactive Foreground Extraction Using Iterated Graph Cuts", GrabCut, ACM Transactions on Graphics (SIGGRAPH'04), vol. 23, no. 3, pp. 309-314, 2004    Non-Patent Document 2: Vincent, Luc, and Pierre Soille, "Watersheds in Digital Spaces: An Efficient Algorithm Based on Immersion Simulations", IEEE Transactions of Pattern Analysis and Machine Intelligence, Vol. 13, No. 6, pp. 583-598, June 1991

Image processing apparatus, image processing method, and computer-readable recording medium


The invention relates to a local radio communication system comprising a central controller (9), several bases (7) which are connected to the controller and several terminals (5) which communicate with the bases. The bases (7) communicate with the terminals using a local radio communication protocol with time division multiple access. Said bases are adapted to real-time transmit chronological information to the controller releasing to the transmissions planned for said bases. The controller is adapted to determine if there is a risk of interferences occurring between the planned transmissions and to impose a chronology for said planned transmissions on the bases in order to limit said interferences.

The present invention relates to local radiocommunication systems.
More particularly, the invention relates to a local radiocommunication system comprising:
at least one central controller,
several bases connected to the controller and controlled by said controller,
and several terminals, each communicating with at least one of the bases, according to a master/slave process where the base plays a role of master and the terminal plays a role of slave at least after setting up a radio link between said base and said terminal, the bases communicating with the terminals according to the same time division multiple access local radiocommunication protocol (for example the BLUETOOTH protocol or the DECT protocol), said protocol providing, for each base, successive time slots during which either an uplink information packet sent by a terminal to said base or a downlink information packet sent by said base to said terminal are transmitted, and said base being adapted to determine in advance and impose planned transmissions between said base and said terminal, said planned transmissions comprising planned transmissions of downlink information and planned slots of uplink information, where the terminal is authorized to transmit an uplink information packet to the base, and at least some of said bases being susceptible to reciprocal interference, preventing the reception by one of said bases of an uplink information packet when another of said bases is transmitting a downlink information packet.
Document WO-A-00/69186 describes an example of a local radiocommunication system of this type.
In a local radiocommunication system of this type, there is, however, a risk of interference between the transmission of an uplink information packet from a terminal to a base and the transmission of a downlink information packet from a different base to a terminal (at the same frequency or at an adjacent frequency).
Such interferences must be avoided since they render the uplink information packets "inaudible" to the bases, due to the fact that the uplink information radio signals are generally received by a base with a power which is substantially weaker than the power of the downlink information signals transmitted by a different base: the uplink information packets thus lost must subsequently be retransmitted, thereby reducing the effective throughput of the radiocommunication system.
The object of the present invention is, in particular, to eliminate this disadvantage by reducing the probability of interference between uplink information packets and downlink information packets.
For this purpose, according to the invention, a radiocommunication system of the type concerned is characterized in that the different bases are adapted to transmit to the controller, in real time, at least chronological information relating to transmissions planned by said bases, and in that said controller is adapted to determine whether there is a risk of interferences occurring between said planned transmissions, and to impose on the bases a chronology of said planned transmissions which enables at least some of said interferences to be avoided.
Thanks to these measures, the controller makes it possible for the majority of interferences between uplink and downlink connections to be foreseen and avoided, taking account of the fact that the large majority of downlink communications are planned in advance by the bases, and that the large majority of uplink communications are authorized by the bases.


An electrolyte membrane is described that has improved bondability with a catalyst layer and that achieves good power generation performance, without the electrolyte membrane undergoing a physical treatment and without any loss of surface modification effect, where the electrolyte membrane comprises a polymer electrolyte and a nonionic fluorochemical surfactant.

Fuel cells are a kind of power generator from which electric energy is extracted by electrochemical oxidation of a fuel such as hydrogen or methanol, and have recently attracted attention as a clean energy source. Above all, polymer electrolyte fuel cells have a low standard operating temperature of around 100° C. and a high energy density. Therefore, polymer electrolyte fuel cells are expected to be widely applied to relatively small distributed power generation facilities as well as to power generators for mobile objects such as automobiles and ships. Polymer electrolyte fuel cells have also attracted attention as a power source for small mobile devices and portable devices, and are expected to be installed in mobile phones, personal computers, and the like in place of secondary batteries such as nickel-hydrogen batteries and lithium-ion batteries.
A fuel cell usually includes, as a unit, a cell including a membrane electrode assembly (MEA) sandwiched between separators. In the MEA, a catalyst layer is arranged on either side of an electrolyte membrane, and a gas diffusion layer is further arranged on either side of the resulting laminate. In the MEA, the catalyst layer and the gas diffusion layer that are arranged on either side of the electrolyte membrane form a pair of electrode layers, and one of the electrode layers is an anode electrode and the other is a cathode electrode. A fuel gas containing hydrogen comes into contact with the anode electrode, and the air comes into contact with the cathode electrode, whereby electric power is generated by an electrochemical reaction. The electrolyte membrane is mainly made from a polymer electrolyte material. The polymer electrolyte material is also used as a binder for the catalyst layer.
Conventionally, Nafion® (manufactured by E. I. du Pont de Nemours and Company), which is a fluoropolymer electrolyte, has been widely used as a polymer electrolyte material. Nafion® exhibits high proton conductivity under low humidification through a proton conduction channel formed by a cluster structure. Meanwhile, Nafion® has problems that it is very expensive because of being produced through multi-step synthesis, and that the above-mentioned cluster structure causes significant fuel crossover. Further, fuel cells are repeatedly subjected to the dry-wet cycle under the operating conditions, and in particular, the electrolyte membrane repeatedly swells and shrinks. In such a process, since the electrolyte membrane is bound by the separators and the like, the electrolyte membrane may be wrinkled or slackened, or broken due to local stress concentration, and may lose the mechanical strength or physical durability. Further, it has been pointed out that Nafion® cannot be used at high temperature because of the low softening point. Moreover, problems such as disposal after use and the difficulty of material recycling have also been pointed out. In order to overcome such problems, an inexpensive hydrocarbon-based electrolyte membrane that can be used in place of Nafion® and that is excellent in membrane characteristics has been actively developed in recent years.
Meanwhile, in order to improve the power generation performance of the fuel cell, it is important that the catalyst layer and the electrolyte membrane have high bondability at the interface therebetween. Conventionally, due to the insufficient bondability at the interface between the catalyst layer and the electrolyte membrane, there has been a problem that the interface may have increased resistance to deteriorate the power generation performance. Therefore, in order to improve the bondability between the catalyst layer and the electrolyte membrane, there have been proposed a method of modifying a surface of the electrolyte membrane, a method of increasing the contact area of the electrolyte membrane with the catalyst layer, and a method of directly applying the catalyst layer to the electrolyte membrane.
Patent Document 1 discloses a method of modifying a surface of an electrolyte membrane by plasma or corona discharge treatment. Patent Document 2 discloses a method of increasing the contact area between an electrolyte membrane and a catalyst layer by forming an uneven structure on a surface of the electrolyte membrane. Patent Document 3 discloses a method of directly applying a catalyst layer to an electrolyte membrane.


An emission layer is formed in a p-layer, and an electron reflecting layer and a hole reflecting layer are formed sandwiching the emission layer. Each of the electron reflecting layer and the hole reflecting layer is constituted by a quantum-wave interference layer with plural periods of a pair of a first layer W and a second layer B. Thicknesses of the first and the second layers in the electron reflecting layer are determined by multiplying by an odd number one fourth of a quantum-wave wavelength of electrons in each of the first and the second layers, and each thicknesses of the first and the second layers in the hole reflecting layer are determined by multiplying by an odd number one fourth of a quantum-wave wavelength of holes in each of the first and the second layers. A luminous efficiency of the LED is improved by electron-hole pairs. The structure in which the emission layer is sandwiched by the electron reflecting layer and the hole reflecting layer is an alternative of a structure in which an i-layer is sandwiched by an n-cladding layer and a p-cladding layer. The emission layer can be formed in a p-layer, and the hole reflecting layer can be formed in an n-layer, an nxe2x88x92-layer or a pxe2x88x92-layer.

1. Field of the invention
The present invention relates to a light-emitting device having at least two pairs of a quantum-wave interference layer that effectively reflects carriers, or electrons and holes, respectively. In particular, the invention relates to light-emitting semiconductor devices including a laser (LD) and a light-emitting diode (LED) with improved luminous efficiency by effectively confining carriers with an active layer.
2. Description of the Related Art
An LD has been known to have a double hetero junction structure whose active layer is formed between n-type and p-type cladding layers. The cladding layers function as potential barriers for effectively confining carriers, or electrons and holes, within the active layer.
However, a problem persists in luminous efficiency. Carriers overflow the potential barriers of the cladding layers, which lowers luminous efficiency. Therefore, further improvement has been required, as presently appreciated by the present inventors.
As a countermeasure, forming cladding layers with a multi-quantum well structure of a first and a second layers as a unit to reflect carriers has been suggested by Takagi et al. (Japanese Journal of Applied Physics. Vol.29, No.11, November 1990, pp.L1977-L1980). Although it can be led that a band gap energy is used as an alternative of a kinetic energy, this reference does not teach or suggest values of kinetic energy of carriers to be considered and the degree of luminous intensity improvement is inadequate.
The inventor of the present invention conducted a series of experiments and, found that the suggested thicknesses of the first and the second layers by Takagi et al. were too small to confine electrons, and that preferable thickness of the first and second layers are 4 to 6 times larger than those suggested by Takagi et al.
Further, the present inventor thought that multiple quantum-wave reflection of carriers might occur by a multi-layer structure with different band width, like multiple light reflection by dielectric multi-film structure. And the inventor thought that it would be possible to confine carriers by the reflection of the quantum-wave. As a result, the inventors invented a preferable quantum-wave interference layer and applications of the same.
It is, therefore, a first object of the present invention to provide an LED in which an emission layer is sandwiched by quantum-wave interference layers with high reflectivity to carriers, functioning as reflecting layers. It is a second object of the present invention is to improve a luminous efficiency of an electron-hole pair by forming an emission layer sandwiched by quantum-wave interference layers in an LED having an emission layer in a p-layer.
In light of these objects a first aspect of the present invention is an LED constituted by two pairs of quantum-wave interference layers Each having plural periods of a pair of a first layer and a second layer as a unit. The second layer has a wider band gap than the first layer. The LED has at least a p-layer and an n-layer, and an emission layer is formed in the p-layer. The emission layer is sandwiched by two pairs of quantum-wave interference layers. Each thicknesses of the first and the second layers in the first quantum-wave interference layer is determined by multiplying by an odd number one fourth of a quantum-wave wavelength of electrons in each of the first and the second layers, and each thicknesses of the first and the second layers in the second quantum-wave interference layer is determined by multiplying by an odd number one fourth of a quantum-wave wavelength of holes in each of the first and the second layers.
The second aspect of the present invention is the LED constituted by the first and the second quantum-wave interference layers each having plural periods of a first layer and a second layer as a unit. Electrons which determine thicknesses of the first and the second layers formed in the first quantum-wave interference layer exists around the lowest energy level of the second layer.
The third aspect of the present invention is the LED constituted by the first and the second quantum-wave interference layers each having plural periods of a first layer and a second layer as a unit. Holes which determine thicknesses of the first and the second layers formed in the second quantum-wave interference layer exists around the lowest energy level of the second layer.
The fourth aspect of the present invention is to define each thicknesses of the first and the second layers in at least one of the first and the second quantum-wave interference layer as follows:
DW=nWxcexW/4=nWh/4[2mW(E+V)]xc2xdxe2x80x83xe2x80x83(1)
and
DB=nBxcexB/4=nBh/4(2mBE)xc2xdxe2x80x83xe2x80x83(2)
In Eqs. 1 and 2, h, mW, mB, E, V, and nW, nB represent a Plank""s constant, effective mass of carriers in the first layer, effective mass of carriers in the second layer, kinetic energy of carriers at the lowest energy level around the second layer, potential energy of the second layer to the first layer, and odd numbers, respectively.
The fifth aspect of the present invention is an LED having a plurality of partial quantum-wave interference layers Ik, formed in at least one of the first and the second quantum-wave interference layer, with arbitrary periods Tk including a first layer having a thickness of DWk and a second layer having a thickness of DBk and arranged in series. The thicknesses of the first and the second layers satisfy the formulas:
DWk=nWkxcexWk/4=nWkh/4[2mWk(Ek+V)]xc2xdxe2x80x83xe2x80x83(3)
and
DBk=nBkxcexBk/4=nBkh/4(2mBkEK)xc2xdxe2x80x83xe2x80x83(4)
In Eqs. 3 and 4, Ek, MWk, mBk, and nWk and nBk represent plural kinetic energy levels of carriers flowing into the second layer, effective mass of carriers with kinetic energy Ek+V in the first layer, effective mass of carriers with kinetic energy Ek in the second layer, and arbitrary odd numbers, respectively.
The plurality of the partial quantum-wave interference layers Ik are arranged in series from I1, to Ij, where j is a maximum number of k required to form a quantum-wave interference layer as a whole.
The sixth aspect of the present invention is an LED having a plurality of partial quantum-wave interference layers arranged in series with arbitrary periods, formed in at least one of the first and the second quantum-wave interference layer. Each of the plurality of partial quantum-wave interference layers is constructed with serial pairs of the first and second layers. The widths of the first and second layers of the serial pairs are represented by (DW1, DB1), . . . , (DWk, DBk), . . . , (DWj, DBj). (DWk, DBk) is a pair of widths of the first and second layers and is defined as Eqs. 3 and 4, respectively.
The seventh aspect of the present invention is to form a xcex4 layer between a first layer and a second layer which sharply varies the energy band and has a thickness substantially thinner than that of the first and the second layers, in at least one of the first and the second quantum-wave interference layer.
The eighth aspect of the present invention is to use at least one of the first and the second quantum-wave interference layer as a reflecting layer for reflecting carriers.
The ninth aspect of the present invention is to constitute a quantum-wave incident facet in at least one of the first and the quantum-wave interference layer by a second layer with enough thickness for preventing minority carriers from being injected into the first layer by a tunneling effect.
(First to Fourth Aspects of the Present Invention)
The principle of the quantum-wave interference layer of the present invention is explained hereinafter. First, the first quantum-wave interference layer, or an electron reflecting layer which reflects electrons, is explained.
FIG. 1 shows a conduction band of a multi-layer structure with plural periods of a first layer W and a second layer B as a unit. A band gap of the second layer B is wider than that of the first layer W. Electrons conduct from left to right as shown by an arrow in FIG. 1. Among the electrons, those existing around the bottom of the second layer B are likely to contribute to conduction. The electrons around the bottom of the second layer B has a kinetic energy E. Accordingly, the electrons in the first layer W have a kinetic energy E+V which is accelerated by potential energy V due to the band gap between the first layer W and the second layer B. In other words, electrons that move from the first layer W to the second layer B are decelerated by potential energy V and return to the original kinetic energy E in the second layer B. As explained above, kinetic energy of electrons in the conduction band is modulated by potential energy due to the multi-layer structure.
When thicknesses of the first layer W and the second layer B are equal to order of quantum-wave wavelength, electrons tend to have characteristics of a wave. The wave length of the electron quantum-wave is calculated by Eqs. 1 and 2 using kinetic energy of the electron. Further, defining the respective wave number vector in first layer W and second layer B as Kw and KB, reflectivity R of the wave is calculated by:
R=(|KW|xe2x88x92|KB|)/(|KW|+|KB|)
=[{mW(E+V)}xc2xdxe2x88x92(mBE)xc2xd]/[{mW(E+V)}xc2xd+(mBE)xc2xd]
=[1xe2x88x92{mBE/mW(E+V)}xc2xd]/[1+{mBE/mW(E+V)}xc2xd]xe2x80x83xe2x80x83(5).
Further, when mB=mW, the reflectivity R is calculated by:
xe2x80x83R=[1xe2x88x92{E/(E+V)}xc2xd]/[1+{E/(E+V)}xc2xd]xe2x80x83xe2x80x83(6).
When E/(E+V)=x, Eq. 6 is transformed into:
R=(1xe2x88x92xxc2xd)/(1+xxc2xd)xe2x80x83xe2x80x83(7).
The characteristic of the reflectivity R with respect to energy ratio x obtained by Eq. 7 is shown in FIG. 2.
When the second layer B and the first layer W have S periods, the reflectivity RS on the incident facet of a quantum-wave is calculated by:
RS=[(1xe2x88x92xS)/(1+xS)]2xe2x80x83xe2x80x83(8).
When the formula xxe2x89xa6{fraction (1/10)} is satisfied, Rxe2x89xa70.52. Accordingly, the relation between E and V is satisfied with:
Exe2x89xa6V/9xe2x80x83xe2x80x83(9)
Since the kinetic energy E of conducting electrons in the second layer B exists around the bottom of the conduction band, the relation of Eq. 9 is satisfied and the reflectivity R at the interface between the second layer B and the first layer W becomes 52% or more. Consequently, the multi-quantum well structure having two kinds of layers with different band gaps to each other enables effective quantum-wave reflection.
Further, utilizing the energy ratio x enables thickness ratio DB/DW of the second layer B to the first layer W to be obtained by:
DB/DW=[mW/(mBx)]xc2xdxe2x80x83xe2x80x83(10).
Thicknesses of the first layer W and the second layer B are determined for selectively reflecting either one of holes and electrons, because of a difference in potential energy between the valence and the conduction bands, and a difference in effective mass of holes and electrons in the first layer W and the second layer B. Namely, the optimum thickness for reflecting electrons is not optimum for reflecting holes. Eqs. 5-10 refer to a structure of the first quantum-wave interference layer for reflecting electrons selectively. The thickness for selectively reflecting electrons is designed based on a difference in potential energy of the conduction band and effective mass of electrons.
Further, the thickness for selectively reflecting holes is designed based on a difference in potential energy of the valence band and effective mass of holes, realizing the second quantum-wave interference layer for reflecting only holes and allowing electrons to pass through.
The electron reflecting layer and the hole reflecting layer as described above function as a p-cladding layer and an n-cladding layer, sandwiching an emission layer which is constituted by an i-layer, respectively. Accordingly, the LED according to the present invention having both the electron reflecting layer and the hole reflecting layer does not necessarily have the emission layer of a conventional LED, which is constituted by an i-layer sandwiched by an n-cladding layer and a p-cladding layer. As a result, the emission layer of the present LED can be constituted by a p-layer or an n-layer. Concerning that a mobility of holes is lower than that of electrons, it is effective to form an emission layer in a p-layer.
(Fifth Aspect of the Present Invention)
As shown in FIG. 3, a plurality of partial quantum-wave interference layers Ik may be formed corresponding to each of a plurality of kinetic energy levels Ek. Each of the partial quantum-wave interference layers Ik has Tk periods of a pair of a first layer W and a second layer B whose respective thicknesses (DWk, DBk) are determined by Eqs. 3 and 4. The plurality of the partial quantum-wave interference layer Ik is arranged in series with respect to the number k of kinetic energy levels Ek. That is, the quantum-wave interference layer is formed by a serial connection of I1, I2, . . . , and Ij. As shown in FIG. 3, electrons with each of the kinetic energy levels Ek are reflected by the corresponding partial quantum-wave interference layers Ik. Accordingly, electrons belonging to each of the kinetic energy levels from E1 to Ej are reflected effectively. By designing the intervals between the kinetic energies to be short, thicknesses of the first layer W and the second layer B (DWk, DBk) in each of the partial quantum-wave interference layers Ik vary continuously with respect to the value k.
(Sixth Aspect of the Present Invention)
As shown in FIG. 4, a plurality of partial quantum-wave interference layers may be formed with an arbitrary period. Each of the partial quantum-wave interference layers, I1, I2, . . . is made of serial pairs of the first layer W and the second layer B with widths (DWk, DBk) determined by Eqs. 3 and 4. That is, the partial quantum-wave interference layer, e.g., I1, is constructed with serial layers of width (DW1, DB1), (DW2, DB2), . . . , (DWj, DBj), as shown. A plurality I1, I2, . . . of layers such as layer I1 are connected in series to form the total quantum-wave interference layer. Accordingly, electrons of the plurality of kinetic energy levels Ek are reflected by each pair of layers in each partial quantum-wave interference layers. By designing the intervals between kinetic energies to be short, thicknesses of the pair of the first layer W and the second layer B (DWk, DBk) in a certain partial quantum-wave interference layer varies continuously with respect to the value k.
(Seventh Aspect of the Present Invention)
The seventh aspect of the present invention are directed forming a xcex4 layer at the interface between the first layer W and the second layer B. The xcex4 layer has a relatively thinner thickness than both of the first layer W and the second layer B and sharply varies an energy band. Reflectivity R of the interfaces is determined by Eq. 7. By forming the xcex4 layer, the potential energy V of an energy band becomes larger and the value x of Eq. 7 becomes smaller. Accordingly, the reflectivity R becomes larger.
Also, by sharply varying the band gap of the interfaces, the potential energy V of an energy band becomes larger substantially and the value x of Eq. 7 becomes smaller.
The reason why the reflectivity becomes larger can be considered as follows. Although the first layer W and the second layer B are formed so as to have the energy level as shown in FIG. 6A, actually some of the source gases to form one layer are mixed with other gases to form the other layer, when the layer to form is switched from one layer to the other. Then the energy level of the two layers does not change critically as shown in FIG. 6B. Accordingly, the first layer W and the second layer B, each having the different band width from that designed as in FIG. 6A, are formed. So, as shown in FIG. 6C, when a xcex4 layer which has a adequately thinner thickness than both of the first layer W and the second layer B and sharply varies an energy band is formed, the quantum-wave interference layer is considered to have the energy level as shown in FIG. 6D even if the source gases are mixed. Consequently, as illustrated in FIG. 6D, the energy level of the quantum-wave interference layer, in which a xcex4 layer is formed at the interface between the first layer W and the second layer B, can be close to the ideal energy level shown in FIG. 6A which is not obtained in the case of no xcex4 layer. Because the xcex4 layers shown in FIG. 6D are substantially thin, a tunnel conduction can be expected in the xcex4 layer. Although the xcex4 layer sharply varies the energy band, motion of carriers may hardly be affected by that.
Variations are shown in FIGS. 5A to 5D. The xcex4 layer may be formed on both ends of the every first layer W as shown in FIGS. 5A to 5C. In FIG. 5A, the xcex4 layers are formed so that an energy level higher than that of the second layer B may be formed. In FIG. 5B, the xcex4 layers are formed so that an energy level lower than that of the first layer W may be formed. In FIG. 5C, the xcex4 layers are formed so that the energy level higher than that of the second layer B and the energy level lower than that of the first layer W may be formed. As an alternative to each of the variations shown in FIGS. 5A to 5C, the xcex4 layer can be formed on one end of the every first layer W as shown in FIG. 5D.
Forming one xcex4 layer realizes large quantum-wave reflectivity at the interface between the first layer W and the second layer B. And forming a plurality of the xcex4 layers realizes a larger reflectivity as a whole.
(Eighth Aspect of the Present Invention)
The eighth aspect of the present invention is directed to a quantum-wave interference layer that functions as a reflecting layer and selectively confines carriers in the front of reflecting layer. As mentioned above, the quantum-wave interference layer can be designed to confine either electrons or holes selectively. Accordingly, by forming two kinds of quantum-wave interference layers each of which functions as an electron reflecting layer and a hole reflecting layer, respectively, both electrons and holes can be accumulated in the layer between the two kinds of the quantum-wave interference layers.
(Ninth Aspect of the Present Invention)
The ninth aspect of the present invention is to form a thick second layer B0 at the side of an incident plane of the quantum-wave interference layer, in order to prevent conduction by tunneling effects effectively and to reflect carriers.

Light-emitting device with a quantum-wave interference layer


The object of this invention is to provide a method and a device for manufacturing semiconductor single crystals by the CZ method in response to the increase in the weight of semiconductor single crystal produced. The necked portion formed beneath the reduced portion can be held and the single crystal under lifting can be re-melted.

1. Field of the Invention
This invention relates to a method and a device for lifting single crystals, said device of which is installed in semiconductor single-crystal manufacturing equipment that utilizes the Czochralski(CZ) method. The method and the device are especially adaptable for lifting heavy semiconductor single crystals.
2. Description of the Related Art
Conventionally, silicon single crystal is produced by the CZ method. In the CZ method, polycrystalline silicon is deposited into a quartz crucible of a single-crystal manufacturing apparatus, then the polycrystalline silicon is heated until it melts by way of heaters disposed around the quartz crucible, subsequently a seed crystal installed within a seed holder is dipped into the melted liquid. Then, the seed holder and the quartz crucible are respectively driven to rotate in the same or opposite directions. At the same time, the seed holder is lifted to grow a single crystal of predetermined diameter and length.
In the seed crystal, dislocation will arise due to the heat shock occurring at the time of dipping it into melted liquid. In order to stop propagation of dislocation from the seed crystal to the single crystal that is to be grown, a reduced portion with diameter from 1 to 4 mm is grown beneath the seed crystal so as to release the dislocation to the surface of the reduced portion. After making certain that the propagation of dislocation has been stopped, a shoulder is formed and the single crystal is enlarged to a predetermined diameter. Then, the lifting operation is shifted to that of forming the body of the single crystal.
In recent years, following the enlargement of single crystals, the weight of an individual single crystal has increased, and the strength of the reduced portion has nearly reached its limit. To solve the problem, a necked portion with a diameter larger than that of the reduced portion is formed on the top of the shoulder when the propagation of dislocation has been stopped by way of the reduction process. It is possible to hold the single crystal by the necked portion so as to prevent breakage of the reduced portion. Alternatively, means are taken to prevent dropping of the single crystal even if the reduced portion breaks. For example, in the single-crystal lifting device disclosed in Examined Japanese Publication NO. 5-65477, 3-4 clamp arms capable of being driven to open or close are engaged with the necked portion of a single crystal so as to suspend the single crystal. In addition, in the single-crystal lifting device disclosed in Examined Japanese Publication NO.7-103000, a plurality of claws engaging with the necked portion of a single crystal are provided. The single crystal is suspended by utilizing a plurality of holding levers capable of being driven to open or to close by their ascending or descending movement and a ring used for preventing opening of the holding levers. Furthermore, in the single-crystal lifting device disclosed in Examined Japanese Publication NO.7-515, a plurality of claws retained at a predetermined angle are provided at the lower end of an engaging holder capable of being driven to ascend or descend. The claws are engaged with the necked portion of a single crystal so as to suspend the single crystal.
However, in the single-crystal lifting device disclosed in Examined Japanese Publication NO. 5-65477, the clamp arm will be driven to open when the weight of the single crystal increases, and there is the danger of dropping of the single crystal during the lifting operation. In the single-crystal lifting devices disclosed in Examined Japanese Publication NO. 7-515 and No.7-103000, there is the danger that the single crystal being lifted might convert into a polycrystal due to the mechanical shock or vibration induced in the process of clamping the single crystal. Furthermore, it is impossible to take the single crystal off from the clamping means,, once the single crystal has been clamped and installed in the main chamber. Thus, even if polycrystallization of the single crystal being lifted or dislocation has occurred, it is impossible to re-melt the single crystal.

Apparatus and method for lifting single crystals