A repeater is used in an in-vehicle communication system for retransmitting communication frames between communication nodes. The repeater includes a storage unit, a retransmission unit, a determiner, and a generator. The storage unit stores a routing map that associates a frame ID that identifies a communication frame from a communication node and a destination of the communication frame. The retransmission unit retransmits the communication frame between the communication nodes based on the routing map stored in the storage unit. The determiner determines whether a preset condition for generating the routing map is satisfied. The generator generates the routing map based on information in the communication frame received from the communication node and stores the map in the storage unit when the determiner determines that the preset condition is satisfied.

A repeater device retransmits communication frames (e.g., communication signals) between communication nodes. The repeater device stores retransmission information for determining a transmission destination (e.g., receiver) of a communication frame received from the transmission source (e.g., sender) of the communication frame. The communication frame includes an ID for identifying the sender communication node.
The relay information may also include a routing map. The routing map provides correspondence information between the sender ID and the receiver communication node associated with the sender ID.
When receiving a communication frame from a communication node, the repeater device may refer to the routing map based on the ID in the communication frame to determine the transmission network and the transmission destination of the communication frame from among a plurality of networks connected to the repeater device.
Repeaters may encounter problems in updating the routing map when new communication nodes are added to the communication network, and thus, are subject to improvement.


Input test pads of an adjacent pattern area are placed in a vacant area of a layout area of output test pads, optimizing the layout area of test pads for use in inspection of a semiconductor chip. Thus, it is possible to miniaturize a semiconductor package.

In tape automated bonding (TAB), the pads of an IC and the leads of a tape are simultaneously connected with all pins according to tape assembly bonding, thereby achieving quite high connecting efficiency for an IC having multiple pins. A TAB package is called a tape carrier package (TCP) and characterized by a small size, a small thickness, and a light weight. A tape used for TAB is called a tape carrier (film carrier). Further, the sprocket holes of a tape and its associated standards are based on American film standards. The manufacturing process of three-layer tapes started from a 350-μm pitch and 40 pins (calculator) and has become finer year by year. The appearance of a thermal head in 1983 has achieved finer pitch at a high pace. Fine pitch is currently led by LCD drivers.
Referring to FIGS. 15 to 19, a method of manufacturing a conventional film carrier will be described below.
FIG. 15 is a diagram showing a process of forming holes on the conventional tape carrier. FIG. 16 is a diagram showing a process of applying photoresist on the conventional tape carrier. FIG. 17 is a diagram showing a process of forming leads on the conventional tape carrier. FIG. 18 is a diagram showing a packaging process on the conventional tape carrier. FIG. 19 is a diagram showing the conventional tape carrier.
First, in FIG. 15, device holes 3 and sprocket holes 2 are formed by die-cutting a film 1 (polyimide, epoxy containing glass, or the like) acting as a base material. Then, in FIG. 16, copper foil 4 is bonded to the film 1, on which the device holes 3 and the sprocket holes 2 have been formed as shown in FIG. 15, while being pressure welded by heat rollers, and photoresist is applied to both surfaces of the film 1. Then, in FIG. 17, mask exposure, development, and etching are performed to form a wiring pattern on the film 1, so that leads 6 are formed protruding from the device holes 3 of the film 1, the device holes 3 having been formed as shown in FIG. 15. Unnecessary resist is removed and Sn plating and Au plating (primary plating) and solder plating (primary Ni plating) are performed on the surfaces of the leads, so that a film carrier process is completed.
The film carrier has a length of 20 to 60 m and the film carrier process is continuously performed on the long film. At the completion of all the processes, the film is wound on a reel via spacers and sent to the subsequent process. Mainly two kinds of pump forming processes are available which include a method of forming bumps on a chip and a transfer bump method of forming bumps on the side of leads. In a typical bump forming method, barrier metal is formed on the pads of a semiconductor chip and bumps are formed thereon by plating method, which is the most widely used. The packaging process of FIG. 18 includes an inner lead bonging (ILB) process in which the leads 6 and the electrodes of the semiconductor chip 7 are connected via the bumps, resin is then applied thereon, and the semiconductor chip is sealed. Thereafter, electrical characteristics are measured using measuring terminals formed on the tape and finally the tape is cut according to the predetermined dimensions of a product area 8.
The inner lead pitch of the TCP started from a 350-μm pitch and 40 pins (calculator) and has become finer year by year. The appearance of a thermal head has achieved finer pitch at a high pace. Fine pitch is currently led by LCD drivers. In recent years, LCD panels have become larger and LCD drivers have had more output terminals. An LCD driver is divided into an input side for digital data of images, a power supply, a control signal, and so on and an output side for output to a panel. More pins have been provided for output signals and output terminals have been aligned with finer pitch in response to high power in recent years.
FIG. 19 shows a semiconductor package of a TAB tape for the conventional tape carrier package formed as shown in FIG. 18. Reference numeral 60 denotes input terminal wires and reference numerals 61, 62, 63, and 64 denote leads acting as output terminal wires. Further, the terminal wires are connected to input test pads 60Tp and output test pads 61Tp, 62Tp, 63Tp, and 64Tp for inspecting the electrical characteristics of products. An electrical inspection is conducted by bringing probes into contact with the test pads. In the case of wires connected from the input/output terminals with finer pitch, the test pads are larger than the wires and thus the test pads cannot be aligned in a single line. In order to avoid this problem, the output test pads 61Tp, 62Tp, 63Tp, and 64Tp are aligned in several lines to secure a test pad area. In this way, fine pitch causes a large test pad area on the TCP, increasing the cost of the package.
One solution is disclosed in Japanese Patent Laid-Open No. 8-24586. As shown in FIG. 20 of a conventional tape carrier with a reduced terminal area, since the number of test pads is smaller on the input side of a TCP package, input test pads 67 on a tape are moved to the upper side or lower side with the minimum pitch, and the input terminals of two semiconductor chips 65 and 66 are placed to face each other, so that a layout area can be shared by input test pads 67 and 68 of the two chips on the tape and each TCP can be miniaturized.

Tab tape and method of manufacturing the same

Matsushita Electric Industrial Co., Ltd.


An apparatus for generating ultraviolet laser radiation according to the present invention includes a laser light source and a frequency conversion device made of a nonlinear optical crystal on which laser light irradiated from the laser light source is made incident and which converts a frequency of the incident laser light to thereby irradiate the ultraviolet radiation. A protective film which prevents oxygen and water content from permeating thereinto is deposited on at least an output end surface, from which ultraviolet radiation is irradiated, of the nonlinear optical crystal. Therefore, it is possible to prevent characteristics of the frequency conversion device from being lowered due to change of a property thereof resulting from increased output power of laser light and to increase a lifetime thereof.

The present invention relates to a high-power ultraviolet laser light generating apparatus having a frequency converter.
There has been an ultraviolet radiation generating apparatus which employs green laser light or ultraviolet laser light as incident light and converts a frequency of the laser light by using a frequency conversion device made of a nonlinear optical crystal to thereby generate ultraviolet laser light or ultraviolet laser light having a shorter wavelength.
A .beta.-BBO (.beta.-BaB.sub.2 O.sub.4) crystal that is a nonlinear optical crystal is frequently used to manufacture the frequency conversion device used in such ultraviolet radiation generating apparatus. Such BBO crystal has no deliquescence and chemical stability and can easily be processed in the air, and hence such BBO crystal is used to manufacture the frequency conversion device used for stably generating ultraviolet radiation. However, when the frequency conversion device made of the BBO crystal is used to generate high-power ultraviolet radiation having a mean output power of 1 kW/cm.sup.2 or higher, a region, from which ultraviolet radiation is irradiated, at an end surface of the BBO crystal is changed in property as time passes. As a result, within a short period of time, i.e., several tens of hours, an optical damage which drastically reduces the ultraviolet light output is produced at the region. Moreover, a so-called Fresnel reflection loss resulting from surface reflection at both of end surfaces of the BBO crystal leads to reflection loss of about 20% of the ultraviolet light output.
As described above, when the ultraviolet radiation generating apparatus generates ultraviolet radiation with a high output power such as a mean output power of 1 kW/cm.sup.2 or higher, change in property of the frequency conversion device, i.e., the nonlinear optical crystal becomes a bar to high-output generation of ultraviolet radiation although it does not become a bar to an ordinary low-power generation thereof.
The inventors of the present invention et al. studied and researched the change in property of the nonlinear optical crystal and found that slight deliquescence in the linear optical crystal, e.g., BBO crystal leads to the change in property which becomes a bar to generation of short-wavelength, i.e., high-energy ultraviolet laser light at high output power.

Apparatus for generating ultraviolet laser radiation


A physiological sensor includes a light source in optical communication with a light detector. A controller is in communication with the light detector via a connector. A booster circuit is in communication with the light detector and the connector. The booster circuit may be configured to buffer signals generated by the light detector and reduce an input capacitance on either the controller or terminals of the connector. In various embodiments, the booster circuit may be disposed on the connector for a reusable cable or a disposable sensor pad.

Physiological sensors are used in medical applications to help doctors diagnose, monitor, and treat patients. The sensors use spectroscopy to provide valuable information about the body tissue. Spectroscopy generally refers to the dispersion of light as it travels through a medium. Light in some regions of the electromagnetic spectrum may disperse differently than light in other regions of the electromagnetic spectrum. For instance, light in the near-infrared region of the electromagnetic spectrum may disperse differently when traveling through body tissues than light in other regions.
A physiological sensor employing near-infrared spectroscopy may be used to detect characteristics of various body tissues by transmitting and receiving near-infrared light through the body tissue, and outputting a signal to a controller that provides valuable information about the body tissue. The information may be used by a doctor to diagnose, monitor, or treat the patient. In some instances, it is necessary to irradiate a single body tissue with different wavelengths of light, and to detect the light at multiple locations. Therefore, multiple sensors are placed in multiple locations, and the sensors are configured to sequentially operate, which requires a long sampling time. However, if too much light is absorbed or dispersed, or if the sampling time is not long enough, the near-infrared light will either not be received or the signal will be too weak to be reliable. Furthermore, a cable connecting a light detector to a controller may cause additional signal losses.
Previous attempts to correct for the weak signal include providing an amplifier with a feedback resistor that minimizes noise created by the amplifier. However, making the value of the feedback resistor too high could severely degrade the performance of the amplifier. In addition, the input impedance of the amplifier may have the characteristics of an inductor. Thus, the light detector and cable capacitance in combination with the amplifier result in a resonant circuit (such as an inductor-current tank) that oscillates. To dampen these oscillations, a capacitor is usually connected in parallel with the feedback resistor and, additionally, the capacitor reduces the bandwidth of the amplifier.
Accordingly, a physiological sensor is needed that provides more accurate and reliable data when too much light is absorbed or dispersed by the medium, or when the sampling time is too short to be reliable. In addition, a physiological sensor is needed that prevents significant signal losses caused by cables that connect the light detector to the controller.

Physiological sensor with booster circuit


The present invention describes an improved RLL channel utilizing a closed-loop clock recovery scheme and a simplified decoding algorithm. (1,7) run-length-limited (RLL) code is used to reduce the magnetic nonlinearity problem posed by prior art PRML systems. In the preferred embodiment of the present invention, the analog data signal amplified, filtered and equalized to approximate an ideal waveform. The signal is then sampled and decoded into binary data. The clock recovery circuit is designed to sample the analog data such that the signal peak lies centered between consecutive sample points. It is thus made possible for the phase error to be extracted from a direct comparison of neighboring sample values. The phase error is then used to adjust the clock signal for the following samples. In the decoding algorithm of the present invention, by making useful approximations, the complexity of the decision functions is reduced, along with the number of required look-ahead samples. The reduction in look-ahead samples reduces the system's sensitivity to misequalization.

1. Field of the Invention
The present invention relates to the field of signal processing in a channel, and in particular, to signal processing in a magnetic recording channel.
2. Background Art
In magnetic recording devices, such as magnetic disks and tapes, a recording head is used to read and write information to and from a magnetic surface. In a typical rotating medium-based storage system, data is stored on magnetic disks in a series of concentric "tracks." These tracks are accessed by a read/write head that detects variations in the magnetic orientation of the disk surface. The read/write head moves back and forth radially on the disk under control of a head-positioning servo mechanism so that it can be selectively positioned over a selected one of the tracks. Once in position over a track, the servo mechanism causes the head to trace a path that follows the center line of the selected track.
Generally, the inductive recording head consists of a slit toroid made up of high permeability magnetic material and wound by several conductor turns. The toroid contains a gap which is positioned over the data tracks on the magnetic recording surface. To record, a current is generated through the conductor windings, altering the magnetic field in the toroid. At the location of the gap, the amplitude of the magnetic field is large enough to record on the magnetic material of the storage device to a sufficient depth. The amplitude of the magnetic field falls off sharply away from the gap. By manipulating the current through the conductor windings, the magnitude and direction of the magnetic flux at the location of the gap can be modulated in such a fashion as to encode information into the magnetic surface of the storage device. A pattern of external and internal fields are created as the head and recording surface are moved relative to each other. These patterns are similar to a series of bar magnets of changing polarities. The polarity transitions are then readable as transitions in the magnetic flux at the recording surface. In read mode, as the magnetic storage surface moves across the gap in the head, the magnetic field of the storage surface is detected at the gap, and a voltage is induced in the coil proportional to the rate of change of the flux. The read channel then processes this analog voltage signal to obtain the digital data.
Magnetic storage devices sometimes use analog peak detection to process incoming read signals. However, as recording density increases, the analog peak detection scheme becomes unreliable because of the large amount of inter-symbol interference (ISI) between adjacent pulses. Alternatively, a partial response maximum likelihood (PRML) channel can be used to increase the recording density. However, this method requires very good equalization of the read signal and the code is completely incompatible with the currently widely used (1,7) run-length limited (RLL) code. More importantly, the required number of magnetic flux transitions per inch is 50 percent higher than that of the (1,7) code at the same density. Therefore, the magnetic non-linearity problem is more severe for the PRML system, and could even render it unusable at high recording densities.
Run-length limited (RLL) codes are useful because they place an upper bound on the number of clock cycles occurring between transitions. Because clock recovery is based on the occurrence of these transitions, this upper bound is very important. For example, a long train of "0's " in a data sequence produces no transitions and the clock recovery circuit has no input pulse with which to synchronize its tracking. In this situation, the data recovery timing might drift out of phase. For this reason, RLL codes are used to insure that sufficient transitions occur for the clock recovery circuit to maintain the correct timing phase and frequency. The (1,7) RLL code is characterized by a minimum of one "0" and a maximum of seven "0's" between consecutive "1's". In an NRZI format, where each "1" is represented by a transition, and each "0" is represented by the lack of a transition, the (1,7) RLL code is sufficient for clock recovery purposes. Also, by maintaining the minimum of one "0" between consecutive "1's", transitions are separated so as to be differentiable from one another.
It is desirable to have a signal processing method that uses RLL codes and can still improve the detection margin at high recording densities. In A.M. Patel's article "A New Digital Signal Processing Channel for Data Storage Products," in Digest of the Magnetic Recording Conference, of June 1991, pp. E6-E7, and in U.S. Pat. No. 4,945,538 issued to Patel, a (1,7) ML channel is described that is intended to achieve these goals.
A block diagram of the channel described by Patel is illustrated in FIG. 1. The analog read signal, originating from the read head, is amplified in preamplifier (preamp) 111 and then provided to filter 112 for the removal of high-frequency noise components. The filtered signal is then provided to phase-locked loop clock circuit 113 and delay line 114. Delay line 114 provides the delayed signal to analog-to-digital converter (ADC) 115 where the signal is digitized. The digitized signal is passed through equalizer 116 to obtain a more desirable waveform, and the result is provided to decoder 118. Decoder 118 implements a decoding algorithm to generate the digital data signal 119. The analog-to-digital converter 115 and decoder 118 are clocked by a clock signal 117 generated in phase-locked loop clock circuit 113.
There are several drawbacks to the (1,7) ML channel. It is difficult, to derive the read clock directly from the sample data. Patel mentions that a conventional peak detection channel is used to provide timing reference for the phase-lock loop, and an adjustable delay line is needed to cancel the timing mismatch between the peak detection channel and the (1, 7) ML channel. Due to the open loop characteristics of this approach, this method is unable to obtain very precise timing recovery. Also, delay lines are costly and unsuitable for monolithic integrated circuit implementation. Another disadvantage is the decoding functions involve five sample values and, therefore, are sensitive to mis-equalization because errors will accumulate in certain data patterns.
With a large number of sample values involved in the decoding operations of a channel, a strict requirement is placed on the equalizer. Because the decoding functions serve to match the sample values against an expected waveform, the equalizer must force the signal to conform to this expected shape. With a smaller amount of sample values involved, the constraints placed on the equalizer are less stringent and are thus more likely to be physically realizable.
FIG. 7A depicts the peak detection clock recovery circuit of the prior art. Input signal 700 represents the output of filter 112 from FIG. 1. Input signal 700 is provided to block 701 wherein its derivative with respect to time is generated as signal 702. However, circuits for generating this derivative are noisy. Therefore, a noise error model is included in FIG. 7A comprising noise signal 703 added to the derivative 702 in adder 704. The resulting signal 705, with the noise superimposed on the derivative signal, is provided to a zero crossing detector 706. Ideally, when the input signal 700 reaches a positive or negative peak, the derivative input to the zero crossing detector will be exactly zero, and the output of the detector, signal 707, will be "1". However, in physical realizations, the noise in signal 705 will cause the actual zero occurrence to be misaligned by the magnitude of the noise error.
Block 708 comprises threshold compactors for indicating whether the input signal 700 has reached a minimum qualifying threshold. When the signal is above a certain positive threshold, or below a certain negative threshold, signal 709 will be asserted. AND gate 710 will output a "1" on line 711 only if both signals 707 and 709 are asserted. The presence of the threshold comparators 708 insures that local peaks caused by noise in signal 700 are not mistakenly interpreted as signal transitions. The assertion of signal 711 signifies a peak. This "peak detected" signal is provided to a standard phase-locked loop 712 comprising a phase detector 731 for receiving signal 711, a loop filter 732 for filtering the output of phase detector 731, and a voltage-controlled oscillator 733 (VCO) controlled by the output of the filter and connected in feedback to the phase detector. The output 117 of the VCO is the clock signal for the system.

Method for processing sample values in an RLL channel


A waterproof and breathable sole for shoes, having a structure including a supporting layer which, at least in a preset macroportion, is made of net, felt or other diffusely perforated material. A membrane made of a material that is impermeable to water and permeable to water vapor is associated above the supporting layer at least in the at least one preset macroportion made of net, felt or other diffusely perforated material, which it covers. A tread made of plastic material, with at least one through macroperforation at the at least one preset macroportion made of net, felt or other diffusely perforated material, is joined hermetically to the membrane and to the supporting layer at least at the perimeter of the at least one macroportion made of net, felt or other diffusely perforated material.

1. Field of the Invention
The present invention relates to an improved waterproof and breathable sole for shoes and to the shoe manufactured with such sole.
2. Description of the Related Art
Waterproof and breathable soles made of plastics for shoes are already known.
One of such soles is disclosed in WO 97/14326.
In this case, the sole comprises:                a mid-sole with a membrane made of a material that is impermeable to water and permeable to water vapor, associated with a lower protective layer of a material that is resistant to hydrolysis, water-repellent, breathable and/or perforated;        a tread made of perforated elastomer, which is joined perimetrically and hermetically to the mid-sole.
The waterproof and breathable sole disclosed in WO 98/51177 is also known; it comprises a preassembled insert in which there is a membrane that is impermeable to water and permeable to water vapor, associated with a lower protective layer made of a material that is resistant to hydrolysis, water-repellent, breathable and/or perforated.
The insert is completed by an element that is overmolded or over-assembled, surrounds the membrane and the protective layer, and is joined hermetically to them.
The insert is part of a mid-sole and is joined, together with said mid-sole, to a tread made of perforated plastic material, which is overmolded or over-assembled.
In both cases, the protective layer arranged below the membrane is designed to protect it against piercing due to foreign objects that have accidentally passed through the holes.
The protective layer is usually made of felt and is coupled to the membrane in a breathable manner (by means of spots of thermoplastic adhesive, for example of the polyurethane-based type) to allow the passage of the vapor from the inside of the shoe toward the outside through the holes provided in the tread.
Breathable and waterproof soles for shoes are also known from U.S. Ser. No. 09/978,634 and EPA No. 01124210.4 and comprise, at least along part of their extension, a lower waterproof component that constitutes the tread, an upper component with a supporting structure that is provided with holes connected to outlets at least on the upper and edge surfaces, and a waterproof vapor-permeable membrane that surrounds externally at least the outward-facing regions of the upper component.
The lower component, the upper component and the membrane are joined hermetically in the regions of possible internal water infiltration.
Although the above described soles have now been available commercially for years and are unanimously acknowledged as being capable of producing an exchange of heat and water vapor between the microclimate inside the shoe and the external microclimate, such soles, in some cases, such as for example use on the part of users with quantitatively higher-than-average foot perspiration, have been found to have a breathability that is insufficient to fully dispose of the generated vapor and ensure the correct microclimate inside the shoe.
The structure of the above described soles in fact has, at least in a downward region, layers of microperforated plastic material, i.e., provided with holes having a diameter on the order of 1-2 millimeters, and the total area of the microperforations in any case limits the area of the membrane that is actually affected by the exchange of heat and vapor.

This patent is subject to a terminal disclaimer.

Waterproof and breathable sole for shoes


A method, computer program, and computer system is provided for partitioning encoded video data. Data corresponding to a video frame is received, and the video frame data may be divided the video frame data into one or more subunits. These subunits may each have unique address values and be arranged in increasing order based on the unique address values. A left boundary and a top boundary associated with each of the subunits may include one or more of a picture boundary or a boundary of previously decoded subunit.

A picture may be divided into one or more tiles. A tile is a sequence of coding tree units (CTUs) that correspond to a rectangular sub-region of a picture. A tile may be divided into one or more bricks. A slice contains a number of tiles of a picture or a number of bricks of a tile. Two modes of slices are supported: a raster-scan slice mode and a rectangular slice mode. In the raster-scan slice mode, a slice contains a sequence of tiles in a tile raster scan of a picture. In a rectangular slice mode, a slice contains a number of bricks of a picture that collectively form a rectangular region.

Flexible slice, tile and brick partitioning


A thin film transistor (1) includes a source electrode (50), a drain electrode (60), a gate electrode (20), a gate insulating film (30), and a channel layer (40) that is formed of an oxide semiconductor, the channel layer (40) having an average carrier concentration of 1×1016/cm3 to 5×1019/cm3, and including a high carrier concentration region (42) that is situated on the side of the gate insulating film (30) and has a carrier concentration higher than the average carrier concentration, and the channel layer (40) having a substantially homogenous composition.

A field effect transistor (FET) has been widely used as a unit electronic device (element) for a semiconductor memory integrated circuit, a high-frequency signal amplifier device, a liquid crystal driving device, and the like. A thin film transistor (TFT) is classified as the field effect transistor. In recent years, the TFT has been widely used as a switching device for various displays that have been rapidly developed. Examples of such displays include a liquid crystal display (LCD), an organic electroluminescence (EL) display, and the like.
The LCD has been the mainstream in the fields of medium and small-sized display panels and large-sized image display panels used for TV applications. Since the organic EL display can achieve high resolution as compared with the LCD, future development thereof has been desired.
The frame rate of the LCD has been increased along with an improvement in moving picture resolution and the spread of three-dimensional displays. It is effective to drive the LCD at a high frame rate for improving the moving picture resolution, and a further increase in high frame has been desired. A large screen, a high resolution, and high frame rate drive have been the keys to the development of displays, and the TFT has been required to achieve performance necessary for implementing these requirements. For example, the TFT has been required to achieve high mobility along with an increase in pixel capacitance for implementing a large screen, an increase in the number of scan lines for implementing a high resolution, and an increase in frame rate.
The mobility of an a-Si:H (hydrogenated amorphous silicon) TFT used for the LCD is about 2 cm2/Vs or less. However, it has become difficult to deal with the above requirements (i.e., large screen, high resolution, and high frame rate drive) for displays when the mobility of the TFT is about 2 cm2/Vs or less.
Since the organic EL device is a current-driven device, and an increase in current value of a drive TFT is required to improve the luminance of the screen, a high-mobility TFT is indispensable for the organic EL display. The TFT used to drive the organic EL display is also required to exhibit current stress reliability in addition to high mobility. Low-temperature poly-Si (LTPS) has been considered to be a candidate for a TFT material that satisfies both high mobility and current stress reliability. When using LTPS, however, the screen size that can be implemented may be limited due to the beam length used during laser crystallization, and the TFT characteristics may show in-plane non-uniformity due to an inter-shot variation of laser light.
A TFT that utilizes an oxide semiconductor instead of a-Si:HTFT or LTPS has attracted attention. For example, a TFT in which an oxide semiconductor such as zinc oxide (ZnO) or indium gallium zinc oxide (IGZO) is used for an active layer (semiconductor layer) exhibits high mobility, and development thereof has progressed.
The oxide semiconductor includes a highly ionic bond, and is characterized in that the difference in electron mobility is small between a crystalline state and an amorphous state. Specifically, a relatively high electron mobility can be implemented even in an amorphous state. Moreover, since the oxide semiconductor is rarely affected by the grain boundary barrier even when the oxide semiconductor is crystallized, it is possible to produce a TFT that is suitable for an increase in area that requires in-plane uniformity. Since a gap state derived from oxygen deficiencies is present in the vicinity of the valence band, holes do not easily become a free carrier as compared with electrons. Therefore, the off current during the operation of the TFT can be reduced to about 10 to 15 A. Since the oxide semiconductor is a wide-bandgap semiconductor as compared with a silicon-based material (TFT), the oxide semiconductor exhibits excellent stability to light in the visible region. Since an amorphous oxide semiconductor film can be formed at room temperature by utilizing a sputtering method or the like, studies have been conducted to form an oxide semiconductor film transistor on a resin substrate (e.g., PET).
As a TFT technique that utilizes the oxide semiconductor, Patent Document 1 discloses a semiconductor device that utilizes a crystalline oxide having an electron carrier concentration of less than 2×1017/cm3 as an n-type semiconductor, and exhibits excellent stability, uniformity, reproducibility, heat resistance, durability, and the like.
Patent Document 2 discloses a TFT in which indium tin oxide (ITO) or the like is used for the channel layer as an oxide conductive material having a high carrier concentration. In Patent Document 2, a reduction in leakage current and an improvement in subthreshold factor are achieved by forming the channel layer consisting of an very thin film (6 to 10 nm) to have a uniform thickness, and planarizing the surface of the gate insulating film to improve the interfacial characteristics.
In Patent Document 3, an oxide semiconductor film having a carrier concentration of about 1×1018 cm−3 is formed by sputtering an oxide sintered body in which gallium is solid-dissolved in indium oxide.
In Patent Document 4, the on-off ratio of a bottom-gate TFT is improved by increasing the oxygen density in the surface layer of the oxide semiconductor as compared with the side of the gate insulating film by applying oxygen-containing plasma.
Patent Document 5 discloses an oxide TFT that includes two active layers formed of indium zinc oxide (or ITO) and GIZO, and states that high mobility and a good threshold voltage are obtained. Specifically, the TFT disclosed in Patent Document 5 has a configuration in which a GIZO layer having a thickness of 60 nm and a low carrier concentration is formed on an indium zinc oxide (or ITO) layer having a thickness of 5 nm and a high carrier concentration.
However, the techniques disclosed in Patent Documents 1 to 5 have the following problems.
According to the technique disclosed in Patent Document 1, since the electron carrier concentration is less than 2×1017 cm−3, it is necessary to improve the mobility.
According to the technique disclosed in Patent Document 2, since the thickness of the channel layer is 10 nm or less, the channel layer may be formed in the shape of an island, and an area in which the semiconductor layer is not formed may occur in the channel layer.
According to the technique disclosed in Patent Document 3, since regions that differ in carrier concentration are not provided in the oxide semiconductor layer, an improvement in subthreshold factor is required.
According to the technique disclosed in Patent Document 4, a high oxygen density region is formed in the semiconductor layer by oxygen plasma treatment to improve the ON/OFF ratio. However, high mobility is not obtained.
According to the technique disclosed in Patent Document 5, since the channel layer having a two-layer structure is necessary, a decrease in productivity and an increase in production cost occur as compared with the case of forming the channel layer using a single material.


A method and apparatus for knurling a workpiece in which the knurl pattern has an oblique helix angle relative to the longitudinal axis of the cylindrical workpiece. Also disclosed is a method of molding a molded article with the knurled workpiece to impart the inverse of the knurl pattern onto the molded article, such a molded article, a method of forming a structured abrasive article with the molded article, and such an abrasive article.

The present invention is useful for making an abrasive article in which a structured abrasive coating is provided on a substrate. The abrasive coating comprises abrasive particles and a binder in the form of a precise, three dimensional abrasive composites molded onto the substrate.
A structured abrasive is a form of an abrasive article in which a substrate bears on a major surface thereof abrasive composites comprising a plurality of abrasive grains dispersed in a binder. The binder serves as a medium for dispersing the abrasive grains, and it may also bind the abrasive composites to the substrate. The abrasive composites have a predetermined three-dimensional shape, e.g., pyramidal. In one form, the dimensions of a given composite shape can be made substantially uniform and the composites can be disposed in a predetermined array. The predetermined array can be in linear form or matrix form.
Such a structured abrasive article can be prepared by a method generally as follows. A slurry containing a mixture of a binder precursor and a plurality of abrasive grains is applied onto a production tool having cavities which are the negative of the final shape of the abrasive composites. A substrate is brought into contact with the exposed surface of the production tool such that the slurry wets the first major surface of the substrate to form an intermediate article. Then, the binder is at least partially solidified, cured, or gelled before the intermediate article departs from the exposed surface of the production tool to form a structured abrasive article. The abrasive article is then removed from the production tool and fully cured if it was not fully cured in the previous step. Alternatively, the slurry can be applied onto the first major surface of the substrate and then the production tool can be brought into contact with the first major surface of the substrate. The precise nature of the abrasive composites provides an abrasive article that has a high level of consistency. This consistency further results in excellent performance.
Structured abrasives, and methods and apparatuses for making such structured abrasives, are described in U.S. Pat. No. 5,152,917, "Structured Abrasive Article," (Pieper et al.), issued Oct. 6, 1992, the entire disclosure of which is incorporated herein by reference. In one embodiment, Pieper et al. teaches an abrasive article comprising precisely shaped abrasive composites bonded to a backing in which the composites comprise abrasive particles and a binder. Pieper et al. teaches, among other things, a method of making the structured abrasive article generally in accordance with the method described briefly above. Pieper et al. teaches that the production tool can be a belt, a sheet, a coating roll, a sleeve mounted on a coating roll, or a die, and that the preferred production tool is a coating roll. Pieper et al. teaches that, in some instances, a plastic production tool can be replicated from an original tool by embossing a thermoplastic resin onto a metal tool, for example. Such a metal tool can be fabricated by diamond turning, engraving, hobbing, assembling as a bundle a plurality of metal parts machined in the desired configuration, or other mechanical means, or by electroforming.
Other examples of structured abrasives and methods and apparatuses for their manufacture are disclosed in U.S. Pat. No. 5,435,816, "Method of Making an Abrasive Article," (Spurgeon et al.), issued Jul. 25, 1995, the entire disclosure of which is incorporated herein by reference. In one embodiment, Spurgeon et al. teaches a method of making an abrasive article comprising precisely spaced and oriented abrasive composites bonded to a backing sheet generally in accordance with the method described briefly above. Spurgeon et al. teaches that, in addition to other procedures, a thermoplastic production tool can be made according to the following procedure. A master tool is first provided. The master tool is preferably made from metal, e.g., nickel. The master tool can be fabricated by any conventional technique, such as engraving, hobbing, knurling, electroforming, diamond turning, laser machining, etc. The master tool should have the inverse of the pattern for the production tool on the surface thereof. The thermoplastic material can be embossed with the master tool to form the pattern. Embossing can be conducted while the thermoplastic material is in a flowable state. After being embossed, the thermoplastic material can be cooled. Spurgeon et al. also teaches that the production tool can be made of a thermosetting resin or a radiation cured resin. While Spurgeon et al. mentions briefly that the master tool can be made by knurling no specific method of knurling a master tool is shown, taught, or suggested by Spurgeon et al.
Two general methods of knurling are known. Knurling is typically performed by the first knurling process, referred to as roll knurling or form knurling. Form knurling is done by pressing a knurling wheel having a pattern on the working surface thereof against a workpiece. The knurling wheel has the inverse of the pattern that is to be imparted to the workpiece. The working surface of the knurling tool is pressed against the workpiece with sufficient force to cold form or press the outer surface of the workpiece into general conformity with the pattern on the knurling wheel. The second knurling process, referred to as cut knurling, is performed by orienting the knurling wheel relative to the workpiece such that the wheel cuts a pattern into the workpiece by removing metal chips. Both conventional knurling processes typically impart a diamond-based pattern in which the diamonds are aligned in the direction perpendicular to the longitudinal axis of the cylindrical workpiece. Conventional knurling processes have also been used to impart a square-based pattern, in which the squares are oriented to have their sides at 45.degree. to the longitudinal axis of the workpiece. As with the diamond-based pattern, the square-based pattern is also aligned in the direction perpendicular to the longitudinal axis of the cylindrical workpiece. These processes are typically used to impart a non-slip pattern on a tool handle, machine control knob, or the like.
One known conventional cut knurling apparatus and method is described with reference to FIGS. 1-10. As seen in FIGS. 1-2, knurling tool 10 is used to knurl a pattern into the outer cylindrical surface 34 of workpiece 30. First knurling wheel 12 and second knurling wheel 14 are mounted onto knurling wheel holder 16. As seen in FIG. 3, tool holder 16 includes a pair of mounting posts which each comprise first portion 20 and second portion 22. Cap screw 18 is inserted through the central opening of the knurling wheel and fastened into the second portion of the mounting post 22. First and second wheels 12 and 14 are free to rotate about axes 26 and 28 respectively. The knurling wheel holder 16 has center plane of symmetry 24. The first mounting post portions 20 are parallel to plane 24. The second mounting post portions 22 are oriented at an angle from the center plane 24. This arrangement orients axis of rotation 26 of the first knurling wheel 12 at angle (a) relative to the center plane 24. Angle (a) is defined as the angle between a plane perpendicular to the plane of the page and including axis 26 and center plane 24 perpendicular to the page. The axis of rotation 28 of second wheel 14 is oriented at angle (b) relative to the center plane 24. Angle (b) is defined as the angle between a plane perpendicular to the plane of the page and including axis 28 and center plane 24 perpendicular to the page Also, as seen in FIG. 6, the orientation of the second portion of the mounting post causes the axis 26 of the first knurling wheel to be inclined towards the workpiece 30 by angle (f.sub.1). Angle (f.sub.1) is defined as the angle between a first plane tangential to the surface of the workpiece at the point of engagement of the first knurling wheel and a second plane perpendicular to the page and including axis 26. Similarly, the axis 28 of the second knurling wheel is inclined towards the workpiece 30 by angle (f.sub.2) seen in FIG. 8. Angle (f.sub.2) is defined as the angle between a first plane tangential to the surface of the workpiece at the point of engagement of the second knurling wheel and a second plane perpendicular to the page and including axis 28.
Knurling wheel 12 is illustrated in greater detail in FIGS. 9 and 10. Knurling wheel 12 has along its outer working surface a plurality of teeth 44. Each tooth 44 includes tooth ridge 48, tooth valley 50 and side surfaces 52. Wheel 12 also includes major opposed surfaces 42 (only one illustrated). Where the side surfaces 52 of the teeth 44 meet the major surface 42, an edge 46 is formed. The teeth 44 have a ridge included angle .theta.. The teeth 44 of second knurling wheel 14 are of the same configuration as the teeth of first knurling wheel 12.
One typical knurling tool 10 is available commercially from Eagle Rock Technologies Int'l Corp. of Bath, Pennsylvania, and is known as Zeus.TM. Cut-Knurling Tool No. 209. As shown in FIG. 3, this knurling tool 10 is typically provided with first and second knurling wheels 12, 14 in which the teeth 44 are oriented parallel to the respective wheel axis 26, 28. Accordingly, the teeth have an included angle (c) measured at the point of contact of the wheels with the workpiece which is the sum of angles (a) and (b), and which is centered on center plane 24. Angles (a) and (b) are typically each 30.degree., resulting in angle (c) being 60.degree.. Under this arrangement, the knurling tool 10 will form a diamond-based knurl pattern, the four-sided diamond bases having opposed 60.degree. corners and 120.degree. corners. This knurling tool 10 also is configured to allow each mounting post to rotate about the longitudinal axes of its respective first portion 20. Such rotational adjustments are calibrated to the diameter of the workpiece 30. The adjustments are intended to orient angles (a), (b), (f.sub.1) and (f.sub.2) to the particular workpiece to allow cut knurling of various sized workpieces.
The operation of known cutting tool 10 is illustrated in FIGS. 1 and 2. The mounting posts are pivoted to the appropriate calibration for the diameter of the workpiece to adjust angles (a), (b), (f.sub.1) and (f.sub.2). Workpiece 30 is rotated by a conventional lathe drive means in direction A. The tool 10 is moved towards the workpiece 30 until the desired engagement between teeth 44 and workpiece 30 is obtained. The rotation of the workpiece 30 in direction A causes the knurling wheels to rotate in the opposite direction. Tool 10 is mounted in a suitable tool drive means as is known in the art, and is traversed in direction B parallel to the longitudinal axis 36 of the workpiece 30. Accordingly, knurling begins at first end 32 of the workpiece 34, and continues in direction B toward the second end (not shown). Because the bisector of the teeth included angle (c) and the center plane 24 of the cutting tool 10 are parallel to the longitudinal axis 36 of the workpiece, the diamond-based knurl pattern is aligned in the direction perpendicular to the longitudinal axis 36 of the workpiece 30.
As mentioned above, known knurling tool 10 is capable of imparting a square-based knurl pattern in a workpiece. This is done by arranging the knurling tool as illustrated in FIG. 4. The knurling tool of FIG. 4 differs from that of FIG. 3 only in that knurling wheels 12' and 14' replace wheels 12 and 14, respectively. In first knurling wheel 12', the teeth 44 are oriented from the wheel axis 26 by first teeth incline angle (d). In second knurling wheel 14', the teeth 44 are oriented away from the wheel axis 28 by second teeth incline angle (e). It is known that angles (d) and (e) can both be oriented relative to axes 26, 28 away from the center plane 24 as illustrated, or both towards center plane 24. Accordingly, the included angle (c) formed by the teeth on each wheel is equal to the sum of angles (a) and (d) added to the sum of angles (b) and (e). With the known commercially available tool described above, angles (a) and (b) are each 30.degree., and angles (d) and (e) are each 15.degree.. This results in the teeth of wheels 12' and 14' each being oriented at 45.degree. from center plane 24. This forms an included angle (c) of 90.degree.. the bisector of which is parallel to center plane 24. The operation of the tool 10 of FIG. 4 is as described above with respect to the tool of FIG. 3.
The pattern imparted by the tool of FIG. 4 will be a square-based pattern which is aligned in the direction perpendicular to the longitudinal axis 36 of the workpiece 30. This pattern is illustrated in FIG. 13. The knurl pattern will comprise pyramids 60 extending outward from the surface of the workpiece. Pyramids 60 will have peaks 62, side edges 64, and side surfaces 66. The base of each pyramid is defined by base edges 68. It is the 90.degree. angle (c) which causes the base edges 68 to form a square. And because the angle (c) is centered on plane 24, the pyramidal pattern is aligned perpendicular to the longitudinal axis 36 of the workpiece 30. This can be seen by noting the peaks 62a, 62b of adjacent pyramids 60 are aligned on a line perpendicular to the longitudinal axis 36 of the workpiece 30.
While the just-described commercially available knurling tool is purported to be a cut knurling tool, careful observation by the present inventors has determined that, surprisingly, the second cutting wheel 14 does not cut a pattern into the workpiece by removing metal chips, but instead cold forms a pattern. In this regard, the known apparatus and method does not perform as a true cut knurling tool as that term is used herein to describe a knurling process in which both knurling wheels cut metal by removing chips. The actual operation of the known knurling method is explained with reference to FIGS. 5-8.
FIGS. 5 and 6 illustrate the orientation of first knurling wheel 12 relative to the workpiece 30. For clarity, the remainder of tool 10 is not illustrated. As seen in FIG. 11, clearance angle .alpha. is formed between the ridges 48 of teeth 44 and the workpiece surface. As seen in FIG. 3, rotation of the workpiece 30 in direction A causes first knurling wheel 12 to rotate in direction of motion M.sub.1. The workpiece rotation A can be resolved into two components: 1) wheel motion M.sub.1 ; and 2) tangential motion T.sub.1 relative to the surface of the workpiece. Tangential motion T.sub.1 is parallel to the longitudinal axis 36 of the workpiece and is in the direction to cause teeth 44 to first engage the workpiece with edge 46, thus causing cut knurling. It call be seen that tangential component of motion T.sub.1 is equal to sin(a). As angle (a) approaches zero, the tangential component T.sub.1 approaches zero, thus the relative motion of the cutting edge 46 of the knurling teeth to the workpiece surface also approaches zero.
As seen in FIG. 5, the relative motion of the workpiece and the first wheel 12 is such that the workpiece is first engaged by the leading edge 46 of each of the respective teeth 44. FIG. 11 is an enlarged partially schematic view illustrating this engagement. The relative motion is indicated by arrows C. It is the edge 46 at the intersection of teeth side surfaces 52 with major surface 42 which acts as a cutting edge to remove material from the surface 34 of the workpiece. Rake angle .beta. is seen to be inclined in the direction of travel of the cutting edge 46. This is referred to as "negative rake angle" and is not as efficient as a positive rake angle, in which the rake angle is inclined away from the direction of travel of the cutting edge. FIGS. 3, 5, 6, and 11 illustrate that first cutting wheel 12 actually performs cut knurling. This is so for sufficiently large values of angle (a) such that tangential motion T.sub.1 is large enough to cause cut knurling.
FIGS. 7 and 8 illustrate the orientation of second knurling wheel 14 relative to the workpiece 30. For clarity, the remainder of tool 10 is not illustrated. As seen in FIG. 12, clearance angle a is formed between the ridges 48 of teeth 44 and the workpiece surface. As seen in FIG. 3, rotation of the workpiece 30 in direction A causes second knurling wheel 14 to rotate in direction of motion M.sub.2. Workpiece rotation A can be resolved into two components: 1) wheel motion M.sub.2 ; and 2) tangential motion T.sub.2 relative to the surface of the workpiece. Tangential motion T.sub.2 is parallel to the longitudinal axis 36 of the workpiece, and is in the direction such that the edge 46 of the teeth 44 is not the first element of teeth 44 to engage the workpiece. It can be seen that tangential component of motion T.sub.2 is equal to sin(b). As angle (b) approaches zero, the tangential component T.sub.1 approaches zero.
As seen in FIG. 7, the relative motion of the workpiece and the second wheel 14 is such that the workpiece is first engaged by the ridge 48 of the tooth rather than the edge 46. FIG. 12 is an enlarged partially schematic view illustrating this engagement. The relative motion is indicated by arrows C. Edge 46 at the intersection of teeth side surfaces 52 with major surface 42 is actually dragged behind the direction of relative motion. Accordingly, the workpiece is first engaged by the ridge 48 away from edge 46. This causes the second wheel 14 to press or form rather than cut and remove material from the workpiece 30.
Thus it is seen that there is a need for a knurling apparatus and method which actually cut knuris a workpiece. There is also a need to provide a knurling apparatus and method in which the knurling pattern does not align itself in the direction perpendicular to the longitudinal axis of the workpiece. Additionally, there is a need to provide a workpiece that can be used to make economically an uninterrupted production tool of any desired length. There is a further need to provide a cut knurling wheel which provides a positive rake angle.

Method and apparatus for knurling a workpiece, method of molding an article with such workpiece, and such molded article


The present invention, in various embodiments, provides techniques for managing system power. In one embodiment, system compute loads and/or system resources invoked by services running on the system consume power. To better manage power consumption, the spare capacity of a system resource is periodically measured, and if this spare capacity is outside a predefined range, then the resource operation is adjusted, e.g., the CPU speed is increased or decreased, so that the spare capacity is within the range. Further, the spare capacity is kept as close to zero as practical, and this spare capacity is determined based on the statistical distribution of a number of utilization values of the resources, which is also taken periodically. The spare capacity is also calculated based on considerations of the probability that the system resources are saturated. In one embodiment, to maintain the services required by a Service Level Agreement (SLA), a correlation between an SLA parameter and a resource utilization is determined. In addition to other factors and the correlation of the parameters, the spare capacity of the resource utilization is adjusted based on the spare capacity of the SLA parameter. Various embodiments include optimizing system performance before calculating system spare capacity, saving power for system groups or clusters, saving power for special conditions such as brown-out, high temperature, etc.

Computer systems including network servers that use electric grids generally operate at full power as long as the power is turned on regardless of the compute load, which is the amount of computation needed to be performed in order to deliver computational services to end users. Compute loads include, for example, central processing unit (CPU) cycles, disk access, memory access, input-output (I/O) access, etc. Laptop computers (laptops) and battery-powered systems entertain various modes of operation such as "sleep," "standby," "hibernate," etc., which reduces power when the system is inactive. However, these power-saving modes are usually based on whether the system is or is not in use, e.g., active or inactive, but not on system performance or system loads. Further, these modes switch the system to full power operation if there is any user activity even though the activity does not require full power. Because servers are seldom completely inactive, they run at full power most of the time without greatly benefiting from the power-save modes that work acceptably for laptops and battery-powered systems. Based on the foregoing, it is desirable that mechanisms be provided to solve the above deficiencies and related problems.

Managing system power based on utilization statistics

Hewlett-Packard Development Company, L.P.


An image forming method is disclosed, which includes steps of cleaning toner remaining on a photoreceptor surface by a cleaning blade which is arranged on counter direction to rotation direction of the photoreceptor, supplying a fatty acid metal salt onto the photoreceptor surface after the cleaning, spreading the supplied fatty acid metal salt on the photoreceptor surface by using a spreading blade which is arranged on trail direction to rotation direction of the photoreceptor, charging the photoreceptor by a charging member, exposing the photoreceptor to form a latent image, developing the latent image by a developer to form a toner image on the photoreceptor, and transferring the toner image onto an image receiving member by a transfer roller facing to the photoreceptor through the image receiving material, in which the toner comprises a binder resin and a colorant, in which the toner has a glass transition point of from 20 to 45° C. and the binder resin contains 50% or more of vinyl polymer resin by weight based on the whole weight of the binder resin.

Recently, necessity of reducing of electric power consumption and amount of wastes wholly caused by image forming apparatus is raised for corresponding to energy and resource saving.
In the image forming apparatus, the amount of electric power consumed by the fixing device is large and reducing such the electric power is effective as the energy saving means. As the resources saving means, it is effective to reduce the amount of scrapped photoreceptor by prolonging the using period by the lifetime of the photoreceptor.
At the present time, the use of low temperature fixing toner for reducing the electric power consumed by the fixing device and the prolongation of the lifetime of the photoreceptor for reducing the amount of scrapping materials are demanded.
Investigation for lowering the glass transition temperature of the toner is carried out to obtain the toner effective for reducing the electric consumption by lowering the setting temperature in the fixing device; cf. Patent Publication 1 for example.
Moreover, it is investigated to prolong the lifetime of the photoreceptor by improving the cleaning suitability by lowering the friction coefficient with the cleaning blade by coating a lubricant on the surface of the photoreceptor for realizing the prolongation of the lifetime of the photoreceptor; cf. Patent Publication 2 for example.
However, a problem of internal lacking of image, hereinafter referred to as internal image lacking, is caused at the characters and dots portion of the printed image when an image printed by applying a toner having a glass transition point of from 20 to 45° C. to an image forming apparatus having a transfer roller.
Patent Publication 3 discloses an image forming apparatus comprising a cleaning blade and a lubricant applying element so that the cleaning area and the lubricant applying area overlap.
Furthermore, digital technology is recently introduced in the technical field of image formation by the electrophotographic system such as copiers and printers for raising the image quality; therefore, it is required to exactly reproduce the image of lines and dots equally in a convenient printing system.    Patent Publication 1: JP A 2001-175025    Patent Publication 2: JP A 2005-352009    Patent Publication 3: WO 2006/062229 A1

Image forming apparatus and image forming method

Konica Minolta Business Technologies, Inc.


Disclosed is x-ray cone beam scan data reconstruction of an imaged object with a reconstruction algorithm using shift invariant filtering and backprojection with the maximum tomographic capability of a circular scan larger than p plus cone angle, when CB data is not truncated and data extrapolation is not allowed. The reconstruction scheme includes a conventional FDK reconstruction and a parallel reconstruction using differential back projection and 1D Hilbert transform to suppress the CB artifacts.

The invention relates generally to medical imaging using X-ray computed tomography (CT), and more particularly the invention relates to reconstructing cone-beam x-ray scan data in tomographic imaging.
Computed tomography is an established medical technique for visualizing internal organs with high resolution. Both fan beams and cone beams (CB) of x-rays are employed in CT.
3D image reconstruction from circular CB data has been an active research field for the last two decades. While the exact reconstruction is achievable on the plane of the source trajectory (mid-plane) if the rotation angle is larger than π plus cone angle, it is impossible outside this central plane (off-plane). Many approximate algorithms have been developed for a circular CB scan. The filtered-backprojection (FBP-based reconstruction, due to Feldkamp et al. (FDK), is by far the most popular algorithm mainly for its structure of one-dimensional (1D) shift-invariant filtering. Although developed heuristically as an extension of the exact fan-beam reconstruction, this algorithm is very close to the optimal in the sense of without data extrapolation. It, however, results in severe CB artifacts in the case of short scan, which is very attractive in many applications, such as in the current C-arm CT. In order to handle the data redundancy, a simple but empirical modification of FDK uses Parker's weighting (P-FDK), which is accurate only for the mid-plane. Unlike the FDK algorithm on a full scan, this algorithm is not the optimal even in the sense of without data extrapolation. Nonetheless, the structure of 1D shift-invariant feature (for computation efficiency), other researchers apply a mathematically exact algorithm to the short scan source trajectory. The derived algorithm, however, does not necessarily achieve the optimal reconstruction.

Tomographic reconstruction for x-ray cone-beam scan data

The Board of Trustees of the Leland Stanford Junior University


A power conversion device includes: a DC current calculation unit for calculating a circulating current component for each phase which circulates between the phases through first arms and/or second arms not via an AC power supply and a DC power supply; and a circulating current control unit for controlling the circulating current component for each phase so as to follow a predetermined circulating current command value, thereby reliably suppressing variation in voltages of DC capacitors of unit cells among the phases even in such a case where an impedance is additionally inserted in a DC circuit.

In a large-capacity power conversion device, since the converter output has high voltage or large current, a configuration having a plurality of converters in series or parallel in a multiplexed manner is often used. It is known that multiplexing a converter not only increases a converter capacity, but also reduces a harmonic contained in an output voltage waveform by synthesizing outputs, and as a result, can reduce harmonic current flowing into a system.
There are various methods for multiplexing a converter: reactor multiplexing, transformer multiplexing, direct multiplexing, etc. In the case of transformer multiplexing, since an AC side is isolated by transformers, there is an advantage that common DC voltage can be used among the transformers. However, there is a disadvantage that, in the case where output voltage is high, the configuration of the multiplexed transformer is complicated and the cost of the transformer increases.
Considering the above, as a power conversion device that is suitable for high-voltage usage and does not require a multiplexed transformer, a multilevel converter is proposed in which outputs of a plurality of converters are connected in cascade. One example of such multilevel converters is a modular multilevel converter (hereinafter, referred to as an MMC).
The MMC is composed of an arm in which a plurality of unit converters called cells (hereinafter, referred to as unit cells) are connected in cascade. Each unit cell includes a plurality of semiconductor switches and a DC capacitor, and through ON/OFF control of the semiconductor switches, outputs both-end voltage of the DC capacitor and zero voltage.
In the case of three-phase MMC, such an arm is individually formed for each phase, an output end of a half number of cells of total cells connected in cascade is used as an AC terminal, both ends of the arms for respective phases are connected to each other, and their respective terminals are used as DC terminals. Since each unit cell output of the MMC is connected to both sides of the AC end and the DC end of the MMC, each unit cell has a characteristic of outputting both DC current and AC current. That is, current flowing in each arm includes an AC component and a DC component. Therefore, in the MMC, it is necessary to control these plural current components. Examples of such control methods are shown in Patent Documents 1 and 2 and Non-Patent Document 1.
These documents disclose that, in an MMC having a DC side connected to a DC power supply and an AC side connected to an AC power supply, AC current is controlled on the AC side of the MMC, and current obtained by removing a component relevant to AC output from each arm current is controlled on the DC side, thus attaining the above control.

TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATION


A solenoid coil bobbin of the present invention for an electromagnetic switch which has a lead wire part of a coil being provided with projections an outer circumference walls adjacent to a pair grooves to be included the lead wire in the opening therebetween, each top end of the projections further having a swollen portion which protrudes in some length from a shape of a hall of the rigid iron core to be inserted the lead wire part therein, so that the swollen portion closes the opening of the lead wire part when inserting the lead wire part in the hall.

This invention relates to an solenoid coil bobbin for an electromagnetic switch of a starter, and specifically to an insulating construction of a lead wire portion.
A conventional electromagnetic switch of a starter is explained with respect to FIG. 3. An exciting coil 1 is wound around a bobbin 10. A rigid iron core 3 supports the bobbin 10. A case 2 holds the rigid iron core 3 as a yoke. A plunger 5 consisting of a magnetic material is held on the front inner surface of the case 2, slidable along the axial direction thereof, and is provided with a rod 6 at the rear end portion thereof as one body. A movable contact 7 is fixed to the rear end portion of the rod 6 in an insulated manner. A pair of fixed contacts 8 is positioned corresponding to the movable contact 7 in the axial direction. A hook 9 is held in the bore of the plunger 5 and is slidable along the axial direction. The front end portion of the hook is in contact with the top portion of a shift lever 9a so as to rotate the lever.
The operation of the conventional electromagnetic switch thus constructed will be described. When the exciting coil 1 is turned on, the plunger 5 is attracted to the rigid iron core 3, and the hook 9 is moved back. Further, the shift lever 9a is rotated so as to link a pinion of a rotating axis of an armature with a ring gear of an engine (not shown). Next, the movable contact 7 closes the pair of fixed contacts 8 so as to start to rotate the starter.
The exciting coil 1 is constructed from an outer coil 1a and an inner coil 1b wound around the bobbin 10 consisting of a synthetic resin (e.g. nylon reinforced by grass-fiber).
The conventional solenoid coil bobbin (Japanese Patent Publication No. sho. 63-8087) will be described with reference to FIG. 4a, and FIG. 4b.
The bobbin 10 is provided with a cylindrical part 12 and flanges 13 and 14 projecting toward the radial direction of the cylindrical part 12 at the both side ends of part 12 so as to define each edge wall of the bobbin. The flange 14 is provided with two notches 15 on the circumferential edge thereof as an inlet for wire passage when beginning to wind the coils 1a and 1b. Moreover, the flange 14 is provided with lead wire elements 18 having a cylindrical shape and projecting from an axial outer surface thereof, with circumferential walls 17 of the lead wire parts 18 provided with line openings 16 along the axial direction thereof and being connected with the notches 15, respectively.
The two lead wire elements 18 have the same structure. Namely, an axial partition 19 which has a narrow width than the line opening 16 is provided in the circumferential wall 17 and projects in the radial direction of the flange 14, so as to form circumferentially adjacent axial grooves 20a and 20b. Each of grooves 20a and 20b is open to the line opening 16 of the wall 17, and connected with one of the notches 15 of the flange 14.
The wall 17 of the lead wire part 18 is constructed from a large diameter part 17a on a side thereof toward flange 14 and a small diameter part 17b projecting in an axial outer direction from the large diameter part 17a. The difference between the large diameter part 17a and the small diameter part 17b is only the diameter, each width value of the grooves 20a, 20b and partition 19 is same in both of the parts 17a and 17b. The small diameter part 17b of the wall 17 is provided with a width slit 17c which connects the groove 20a with a circumferential surface of the small diameter part 17b. Moreover, a circumferential surface of the large diameter part 17a of the wall 17 is provided with projections 16a and 16b disposed on the edges of the line opening 16. The above-mentioned parts consist of synthetic resin as one body.
In the above mentioned bobbin, after winding the inner coil 1b, the outer coil 1a with its lead wire (not shown) is passed through the groove 20a (shallow side) wound around the inner coil 1b. After this, the projections 16a and 16b disposed along the edges of the line opening 16 of the lead wire part 18 are bent to the inside of the opening by heat softening so as to close the line opening 16. As a result of closing, the large diameter part 17a of the circumferential wall of the lead wire part 18 would not only have a surface without discontinuous portions, but also prevent escape of the lead wire from the grooves 20a and 20b. The constructed lead wire part 18 is inserted in a wall of the rigid iron core 3 of the electromagnetic starter 2 using the bobbin.
The above bobbin of the conventional electromagnetic switch has a problem in that the producing processes for providing the projections 16a and 16b on each edge of the grooves 20a and 20b are expensive and in that bending the projections 16a and 16b by heat softening increases the production period and expense.

Solenoid coil bobbin for electromagnetic switch


The unbalance of a body (10) to be balanced is indicated in a polar co-ordinate system (52) on a screen (50) of a cathode ray tube (48) by means of a first visible mark (60). The body (10) to be balanced may be rotated by a drive motor (20) by means of a belt (22). A pulse generator (30), producing trains of pulses that are relatively phase displaced by a quarter of a period, is coupled to the drive motor (20). A computer (34) generates a position-indicating signal from the pulse trains, and a reference signal is produced by a reference mark on the body (10) to be balanced and obtained from a pick-up device (28). A position-indicating radial finger (68), which is a second visible mark and rotates on the screen (50) in phase locked manner with the body (10) to be balanced, is obtained from the position-indicating signal. When the position-indicating radial finger (68) coincides with the first visible mark (60), the unbalanced body (10) is positioned in the desired working position. It is possible to depict on the screen (50) angular positions of unbalance even though the rotation of the body (10) to be balanced is not phase-locked with the rotary drive by the motor (20), because, unlike the prior art which merely counts pulses, the respective ratios of the number of pulses generated by movement of the body (10) from the reference position thereof to sequential momentary positions thereof in relation to the number of pulses in a complete revolution of the rotating body (10) to be balanced is determined and used instead.

1. Technical Field
The present invention relates to apparatus for and methods of locating and correcting unbalance in a body to be balanced. In its more particular aspects, the invention provides apparatus and method for measuring an unbalance in a body to be balanced by displaying on a screen representations of positions of the body as it rotates.
2. State of the Art
The process of balancing a rotor comprises two steps. The first step consists in measuring the unbalance in terms of its angular position and its magnitude during a test cycle. The second step consists in balancing out the unbalance determined during the test cycle by removing or adding material at particular points on the body to be balanced In the case of "polar balancing" the balancing must be effected in each balancing plane at the position which corresponds to the angular position of unbalance discovered during the test cycle. Consequently, it is necessary to rotate the body to be balanced into the corresponding working positions for correcting the unbalance.
For each working position, the part of the body at which material must be removed or added must be suitably placed for such a corrective operation, which is usually carried out by a metal working device. The rotating of the body to be balanced into the working position may take place on the same machine that was used for obtaining the measurements (balancing machine). However, the rotating of the body to be balanced into its working position may be performed on a special balancing machine to which the stored results of the measurements are conveyed. The "working" at the working position may consist in a direct balancing of the unbalance. The working may, however, consist in a marking of the spot where the unbalance occurs for a subsequent balancing operation.
The unbalance of a body to be balanced is usually measured dynamically at two axially displaced, radial planes, the "balance planes" with the aid of a balancing machine. The angular position and magnitude of the unbalance is determined for each of these planes. Force or displacement sensors deliver, via a known electric circuit or computer, a combined AC signal having the same frequency as the body to be balanced for each of these balance planes. The amplitude of the AC signal provides a measure of the magnitude of the unbalance. The phase of the AC signal provides a measure of the angular position of the unbalance. A known process of determining the angular position of an unbalance consists in comparing the AC signal with two reference AC signals which also have the same frequency as that of the body to be balanced and which are phase-locked therewith but which are 90.degree. out of phase with each other. Consequently, the AC signal can be multiplied with each of the reference signals at each time point.
Alternatively, each of the reference signals may be used to control a phase-sensitive demodulator and the AC signal can be mixed in the two phase-sensitive demodulators. If the body to be balanced is being driven by a motor which is phase locked with the rotation of the body, e.g. via a Cardan shaft, then the reference signals can be produced by a generator connected to this motor. However, if such a phase-locked type of driving connection is not available and the body to be balanced is being driven by a belt for example, or if the measurements are being taken when coasting, then a mark can be put on the body and this mark can be detected, (e.g. with a photoelectric detector). Such a mark and detector arrangement provides reference signals from which AC or rectangular pulse reference signals can be generated. In this way, one can obtain by suitable mixing of the AC signal and the reference signals (multiplication or pulsed rectification) two values, usually in the form of DC signals, which correspond to the unbalance components. The latter are expressed in terms of points of a co-ordinate system which is defined relative to the body and the angular position of the generator connected to the motor or the angular position of the mark on the body.
It is known to use the thus obtained components to produce a direct indication of the magnitude and angular position of the unbalance on a screen.
In one known indicating arrangement of this type, two watt meters are arranged at a mutual angular spacing of 90.degree. and receive the signals from the sensors sensing the centrifugal force exerted by the body to be balanced during its rotation. The watt meters are provided with mirrors which are also mutually angularly offset by 90.degree.. A light beam is directed to the two mirrors during rotation of the body to be balanced. The reflected light beam is directed to a diffused plate, e.g. ground glass screen, having a polar coordinate system inscribed thereon. The light beam is reflected by the two mutually perpendicular mirrors in accordance with the two mutually perpendicular components of the unbalance and generates a resultant point of light at an angular position in the polar magnitude of the unbalance. It is also known in a balancing machine of this type to store the light point indications so that they are maintained even after the ending of the test cycle and the stopping of the apparatus. It is also known to indicate the magnitude and the angular position of the unbalance by means of a cathode ray tube wherein the two signals corresponding to the unbalance components are used to control the electron beam in two mutually perpendicular directions.
In order to rotate the body to be balanced into its working position, a second light mark (position marker) is then created on the same screen. This second mark indicates the rotational positions assumed by the body during the rotating process. When the body has been so rotated that the second mark coincides with the stored mark, then the body is in its working position. This operation is carried out by rotating a projector or mirror conjointly with the body to be balanced. This projector or mirror is coupled in phase-locked relationship to the drive motor rotatingly driving the body to be balanced, by means of an "electric shaft" i.e. a rotating field system transmitter and receiver. The transmitter has a rotor which is coupled to the drive motor and the receiver has a rotor which is coupled to the projector or mirror. This system requires that the drive motor is coupled in phase-locked relationship to the body to be balanced.
If no such phase-locked driving connection is available, other systems are known for monitoring the rotation of the body to be balanced into its working position for correcting the unbalance. Such systems which are known from European Patents No. 0,074,416 and 0,085,873, do not rely upon indicating arrangements of the type as described hereinbefore.
From European Patent No. 0,074,416, a balancing machine is known in which a body to be balanced is driven by a belt, i.e. the drive motor does not rotate synchronously with the body. A pulse generator is coupled to the motor. A mark on the body to be balanced is detected by a pick-up device and delivers a reference signal at each revolution of the body. A counter counts the number of pulses generated by the pulse generator between each occurrence of a reference signal. In this way, the number of pulses corresponding to a full revolution of the body is determined. By multiplying this number by the ratio of the measured rotational angle of unbalance and 360.degree., the number of pulses corresponding to the angle of unbalance is obtained. Thereafter, the body to be balanced is rotated into its working position in which the reference mark is located at the working position. The body to be balanced is, then, further rotated until the counted pulse number is equal to a stored pulse number representative of the angular position of the unbalance relative to the reference mark or until such stored pulse number is counted down to zero.
From European Patent No. 0,085,873, a balancing machine is also known in which a pulse generator is coupled to an idler roller of the balancing machine. A mark is made on the body to be balanced. This mark is detected by a pick-up device and thereby produces a reference pulse. A measurement pulse is derived from the AC signal. The phase of the measurement pulse relative to the reference pulse provides an indication of the angular location of the unbalance relative to the mark. During a test cycle, the pulses emanating from the pulse generator are counted from the occurrence of the reference pulse up to the appearance of the measurement pulse. The resultant count is stored. The rotating of the body to be balanced is then accomplished with the aid of the pulse generator in accordance with the count.
The balancing machines according to European Patents No. 0,074,416 and 0,085,873 rely upon pulse counting and count comparison operations for rotating the body to be balanced into the working position. Due to the lack of a phase-locked driving connection between the rotary drive means and the body to be balanced, the aforenoted screen displaying functions can not be employed in such balancing machines for indicating the rotation of the body to be balanced into the working position for correcting the balance.
Also, there exist a number of cases in which a phase-locked driving connection between the body to be balanced and the rotary drive means would be undesirable for measuring and correcting the unbalance because the Cardan shaft which provides the phase-locked driving connection, would affect the result of the measurements due to the occurrence of laterally directed forces. In such cases it would be highly desirable to carry out such measuring and correcting operations without making use of the phase-locked driving connection even if it is present.

Apparatus for turning a body to be balanced into a working position


Described is a technology by which the identity of a person (e.g., a customer in a commercial transaction) is determinable without active identification effort, via biometric data is obtained without action by the person. Machine processing of the biometric data over a set of possible persons, determined from secondary proximity sensing, is used to determine or assist in determining the identity of the person.

There are many situations in which it is desirable to identify a person. For example, many forms of payment today require customers to provide a form of authentication to a store, e.g., when paying with a credit card, the customer needs to be able to reproduce the signature found on the back of the card. This constitutes a weak form of identification. If the transaction has a high monetary value, the customer may be required to provide additional forms of identification, such as a driver's license. Similarly, employers may issue "food cards" to their employees that serve to authenticate the employees when making a purchase, and link their identity to an account from which money for the purchase can be deducted.
Card presentation and verification schemes, along with checking signatures and/or government-issued photo IDs, are subject to errors on the part of the merchant's clerk or the like. Such schemes also require non-negligible effort on the part of the customer, e.g., remembering to bring a card, a photo identifier, carefully signing and so forth.
A different to ascertain a person's identity is through the use of biometrics, including face recognition, retinal and/or iris scanning, fingerprint reading, voice identification and so forth. However, many forms of biometrics are invasive; for example, it is not reasonable to ask an employee to subject himself or herself to short-range iris scanning to buy lunch, (nor is it currently practical from an expense and maintenance perspective). At the same time, contemporary non-invasive types of biometrics such as face recognition technology are not sophisticated enough to provide the level of accuracy that is needed for a payment scheme.
What is desirable is an identification scheme that requires virtually no effort on the part of the identified person. At the same time, to be useful such a scheme needs to be reasonably practical, non-invasive, secure and accurate.

Personal identification combining proximity sensing with biometrics


In general, a wire retainer according to the present invention includes an exterior retaining wall having a first dimension adapted to be inserted through the aperture between the resilient fingers of the wiring duct, an interior retaining wall, a projection which extends normal to the interior retaining wall, and a duct engaging portion, disposed between a portion of the interior and exterior retaining walls, for securing the wire retainer at any selected vertical height between adjacent resilient fingers, having a first dimension substantially similar to the exterior retaining wall first dimension, and a second dimension larger than the duct engaging first dimension, whereby the second dimension interferingly engages adjacent resilient fingers after insertion and one-quarter turn rotation of the wire retainer.

Wireway systems including channel-shaped ducts having upstanding fingers constituting slotted side walls have been in general use for years because of their convenience in channeling, selectively routing and retaining the various wires of a wire bundle interconnecting the components of an electrical system. These ducts typically have a cover for retaining the wires in the duct after completion of the wiring. A problem encountered with the use of such ducts is that during the wiring or when the cover is removed to permit maintenance, individual wires may tend to fall out of the duct due to the resiliency of the wires. This problem is particularly acute when the duct is nearly filled with wires or when the duct is vertically mounted.
Because of these difficulties, plastic retaining fingers have been proposed for retaining previously installed wires in the duct until the wiring is completed and the cover mounted on the duct. These various retaining fingers attach to one wall of the duct and extend partially across the duct opening.
More particularly, one such retainer has a bifurcated base portion comprising resilient legs for engaging the wall and a finger portion extending from the base portion partially across the duct opening. When such a finger is attached to the sides of adjacent upstanding fingers forming a slot in the wall, the retaining finger tends to fall to the bottom of the slot where it interferes with the introduction of additional wires in the duct. This occurs because the force applied by the resilient legs slightly deflects the upstanding fingers in the longitudinal direction of the duct. To overcome this disadvantage, auxiliary closed slots for mounting the retaining fingers are required in the individual upstanding fingers. However, the closed slots typically do not extend near the top of the duct wall, thus precluding use of the retaining finger when the duct is nearly filled with wires. Furthermore, the resiliency of the legs diminishes with repeated usage or when the retaining finger is subjected to heat, causing the plastic to soften, as when the wireway system is mounted on a hot control panel. Such a wire retainer is shown in U.S. Pat. No. 3,705,949.
Another type of retainer was proposed which was disposed between two adjacent side wall fingers. This design did not use resilient legs to engage the fingers, rather a more rigid finger design was used. This design incorporated two small plane portions, separated by the thickness of the side wall fingers, which were ratcheted between two adjacent fingers then locked into a maximum vertical height position. This is the only height position which may be selected, and if the retainer is not locked into the maximum height position, it will fall to the bottom of the duct wall where it interferes with the introduction of additional wires into the duct. Another disadvantage is the extreme ratcheting and corresponding bending of the side wall fingers which is required, and consequently makes installation very difficult. Furthermore, since the planar portions are relatively small, when the retainer is bumped or jarred, it easily becomes displaced from a mounted position. The reason for this is that the bumping or jarring action often mimics the installation procedure, thus unistallation is common. The result is a wire retainer which is limited in use, difficult to install, and easy to displace unintentionally. Such a wire retainer is shown in U.S. Pat. No. 3,890,459.
A third type of wire retainer engages a single specially-made duct finger with resilient C-shaped legs and a groove or bump engaging locking mechanism. Each duct finger has a multitude of grooves or bumps disposed thereupon to permit segmented height adjustment of the wire retainer. A projection or dog is disposed upon the wire retainer which engages the groove or bump and secures the retainer into position. However, such an arrangement does not adequately permit a maximum height selection when used with a duct cover. Furthermore, the intricate design of the wire retainer makes it difficult and expensive to manufacture. The specially required duct is also more expensive to manufacture, but necessary in order to provide selective height adjustment. The result is a wire retainer which is complicated and expensive to manufacture and only provides complete performance with one specific certain type of wiring duct. Such a wire retainer is shown in U.S. Pat. No. 4,136,257.
One major disadvantage of all of the prior art designs is that each will only work with one certain type of duct, that which is specifically manufactured for it.
Therefore, in the design of wire retainers, a less expensive, easier to manufacture and more widely applicable design is desired and improvement in the art of wiring duct wire retention is needed.


A dielectric filter includes a dielectric ceramic block provided with three or more than three linearly arranged resonators. Coupling through bores are arranged between adjacent ones of the resonators and input/output pads are arranged vis-a-vis the respective outermost resonators for capacitive coupling. There are provided a pair of outer coupling electric paths extending from the respective input/output pads onto the open-circuit end surface which are arranged in juxtaposition with the respective outermost resonators with a coupling gap provided therebetween. A pair of inner coupling electric paths extends from the respective input/output pads onto the open-circuit end surface and are arranged between the outermost resonators in juxtaposition with the inner resonator or the respective inner resonators adjacent to the outermost resonators. A coupling gap is provided therebetween so as to remarkably reduce or eliminate the influence of the fly back x and consequently improve the attenuation performance of the dielectric filter.

1. Field of the Invention
The present invention relates to a dielectric filter comprising a plurality of juxtaposed resonators, and a duplexer using such resonators.
2. Prior Art
FIG. 1 of the accompanying drawings illustrates a known typical dielectric filter comprising a dielectric ceramic block A, three or more than three resonators B provided in the block A respectively by coating the peripheral walls of three or more than three through bores with a conducting material, an external conductor C covering the outer surfaces of the dielectric ceramic block A but not open-circuit end surface having the openings of the through bores, a pair of coupling through bores D arranged between adjacent ones of the resonators B in parallel with the latter and having no coating on the peripheral walls thereof and a pair of input/output pads E arranged on a lateral surface of the dielectric ceramic block A at respective positions abutting the open-circuit end surface of the block A and facing the respective outermost resonators in such a way that they are electrically insulated from the external conductor C. With such arrangement the magnetic field coupling intensity of the adjacent resonators may be intensified because dielectrics are cleared off between adjacent resonators B by a coupling through bore D. A variety of such dielectric filters are currently known.
With such a known arrangement, however, a fly back x (see FIG. 4B) is produced at an attenuation pole in a higher frequency zone of a resonance frequency band under the influence of the coupling through holes D to hold the output level above the threshold value of -50 dB as shown in FIG. 4B and reduce the attenuation w to such an extent that the filter does not operate satisfactorily in terms of attenuation and is apt to generate noise.
It is therefore an object of the present invention to provide a dielectric filter that is free from any degradation in the attenuation effect of the filter due to a fly back x.
Another object of the present invention is to provide a duplexer using such dielectric filter.


Metallic materials having a melting point of at least 2000° C. are caused to abut against each other in a welding part. The rear face side of the welding part is covered by a backing member having a thermal conductivity of 30 W/mK or lower, and then a columnar probe of a rotary tool comprising an Ir alloy is inserted into the front face side of the welding part to weld the metallic materials together. On the front face side of the welding part, inactive gas is supplied into a shield cover. The rotary tool is moved along a longitudinal direction of the welding part while rotating the rotary tool, whereby the metallic materials are welded together. By using the rotary tool comprising an Ir alloy, the refractory metals can be welded to each other by means of friction stir welding.

When melt-welding a refractory metal having a melting point of at least 2500° C., such as tungsten (W), molybdenum (Mo), tantalum (Ta), rhenium (Re), and alloy consisting primarily of these metals, or a refractory metal having a melting point of at least 2000° C., such as iridium (Ir) and alloy consisting primarily of this metal, the welding part forms a solidification structure and becomes polycrystalline with coarse grains. The refractory metallic materials described above have brittle crystal grain boundaries, which is a cause of a fatal defect in the welding part. Therefore, welding the above refractory metallic materials is conventionally performed mainly by means of rivet welding.
On the other hand, a technology for welding a metallic material by means of friction stir welding (FSW) has been known as a method for welding a metallic material. When performing the friction stir welding, metallic materials to be boned are placed to face a welding part. Then, a probe provided at a leading end of a rotary tool is inserted into the welding part, and the rotary tool is rotated and moved along a longitudinal direction of the welding part and the metallic materials are subjected to plastic flow by frictional heat to weld the two metallic materials to each other (see Patent Literature 1, for example).
Patent Literature 1: Japanese Patent Application No. 2792233
Although friction stir welding can basically achieve good welding strength, friction stir welding is generally employed for low-melting metals such as aluminum (Al) and magnesium (Mg). Hence, application of friction stir welding is limited to ferrous materials in the research steps, and friction stir welding is not performed on the above refractory metals.