The present invention is a nitride compound semiconductor laser, in which a cleaved end face is flat, and a breakdown of a laser end face induced during an operation can be suppressed, which consequently enables a life to be prolonged. In the nitride compound semiconductor laser, a stress concentration suppression layer is formed between an active layer and a cap layer.

The present invention relates to a nitride semiconductor laser characterized by having a stress concentration suppressing layer between an active layer and a cap layer.
A GaN-based group III–V compound semiconductor (hereafter, referred to as a GaN-based semiconductor), which is a direct transition semiconductor whose forbidden band gap is in a range from 1.9 eV to 6.2 eV, enables a realization of a semiconductor light emitting device, such as a semiconductor laser diode (LD), a light emitting diode (LED) and the like, in which a light emission can be obtained from a visible region to a ultraviolet region. Thus, in recent years, development in the field has been vigorously advanced. Among them, actual usage of a blue-violet semiconductor LD from which a light having a light emission wavelength of about 400 nm is obtained is especially required in order to improve a recording density of an optical disc or the like, in a field of an optical recording. Also, a blue semiconductor LD having a light emission wavelength of about 460 nm is expected to be applied to a laser display. Moreover, an ultraviolet semiconductor LD having a light emission wavelength of 380 nm or less is expected to be applied to a light source for phosphor excitation.
Those GaN-based semiconductor light emitting devices are typically provided with GaN-based semiconductors grown on a substrate. Conventionally, as the substrate on which this GaN-based semiconductor is grown, there is no proper substrate having an excellent lattice matching property with GaN. Thus, a sapphire substrate is mainly used. However, a lattice mismatching with the GaN and a thermal expansion coefficient difference from it are very large. In this way, when the lattice matching with the substrate is poor and the thermal expansion coefficient difference from the substrate is large, influence on a crystallinity of a GaN-based semiconductor layer grown on the substrate is severe. Hence, a large quantity of dislocations, such as on an order of 108 to 1010/cm2, is implanted into the GaN-based semiconductor layer in order to relax that distortion. Among them, a threading dislocation especially transmitted in a thickness direction of a film is harmful for an active layer of a device formed near a film surface, and it acts as a current leakage portion and a non-light-emission center. So, threading dislocation is known to damage electrical and optical properties of the device.
Thus, in order to manufacture the GaN-based semiconductor device, threading dislocation must be reduced as much as possible. In recent years, as a method of reducing threading dislocation, an epitaxial growth method has been employed which uses a lateral direction growth, which is represented by an ELO (Epitaxial Lateral Overgrowth) method. The present inventors have employed the ELO method and tried to reduce a dislocation density of a GaN epitaxial film. At that time, the dislocation density within a Wing portion (a portion resulting from the lateral direction growth) under an optimized condition could be reduced to an order of about 106/cm2 or less. As a result, in the above-described GaN-based semiconductor laser manufactured by the present inventors, it was evident that a device life was improved by such as about 200 hours under conditions of 50° C. and 30 mW.
However, even in the case of the above-mentioned GaN-based semiconductor laser, it is difficult to say that those result can be sufficiently attained in actual usage. There is a margin for further improvement so as to improve the device life.
A subject of the present invention is to provide a nitride semiconductor laser, in which a cleaved end surface is flat, and a breakdown of a laser end surface induced during operation can be suppressed, resulting in a long life.


A cable management device, which comprises a body having an axis and at least one planar flange and at least one cable retainer; this apparatus allows for removable attachment of a cable during axial winding in a single plane, which results in uniform and neat storage of cable or cord.

1. Field of the Invention
This invention relates to cable and cord management devices.
2. Description of Related Art
Since the advent of electricity and the telephone, there has been the need to store and to manage loose and free electrical cables and insulated wires. These non-tethered and loose cords create clutter, confusion, and even safety hazards. With the advances in computers and electronic devices, including but not limited to Compact Disc (CD), MP3, cassette, radio and television receivers, Global Positioning Sensor (GPS), cellular and satellite telephones, and Portable Digital Assistant (PDA) devices, there has been a greater need to manage power and data cables. Any person, who looks behind their desktop computer, understands the dilemma of a multitude of unorganized cords and cables.
Even with the advent of wireless communication technology, there still is a need to connect the device to a power source. Currently, most electronic devices have a standard six-foot power or attachment cable, which are not retractable. Most cables are packaged with plastic ties or rubber bands to tie up the cable, but these devices are ineffective because the cords and cables end up being wound up in a tangled and unorganized manner, which can inevitably lead to tangled and damaged cords. Also, these devices do not allow for a quick and an easy length or position adjustment.
Many of these devices are bulky, conspicuous, obtrusive, and not readily portable. Many companies and designers go through a tremendous amount of effort to produce an elegant and beautiful device, and providing an accessory to gracefully and inconspicuously manage the cables and cords of these devices is required.
To address these problems, the inventor presents a suite of cable management devices that employ "Ultra-Thin Cable Management," which allows for neatly and uniformly storing and wrapping a cable in such a manner to prevent tangling and damaging of the cable. This invention allows for easy adjustment of the length of the cable, removal and unwinding of the cable, and placement of the apparatus on or near the electronic or computing device. This invention provides for multiple placement options including associating the cable management device directly with the electronic device or to furniture, tables, chair, desks, and the workspace.
From the preceding descriptions, it is apparent that the devices currently being used have significant disadvantages. Thus, important aspects of the technology used in the field of invention remain amenable to useful refinement.

This patent is subject to a terminal disclaimer.


An audio power amplifier includes a differential amplifier circuit that serves as an input circuit. The differential amplifier circuit includes a signal GND (SG) terminal that receives a SG voltage, and an audio signal input terminal that receives an audio signal. A SG voltage generation circuit is provided to output the SG voltage. The SG voltage generation circuit includes a voltage follower amplifier that outputs a current, a reference voltage source that is input to the voltage follower amplifier, and a current control circuit that controls the current output from the voltage follower amplifier. The SG voltage rises in a prescribed manner while suppressing a pop sound during its transition.

1. Technical Field
This disclosure relates to audio power amplifiers, systems, constant voltage generation circuits, and amplifier circuits for use in a speaker system, and in particular to such audio power amplifiers, systems, constant voltage generation circuits, and amplifier circuits, which employ a pop sound reduction circuit and reduce so called a pop sound likely generated when a power supply is turned on/off or a standby mode is terminated.
2. Discussion of the Background Art
It is well known that a speaker system sometimes generates a strange shock sound called a pop sound when a power supply is turned on/off or a standby mode is terminated and a voltage increases, i.e., in a transition period, at applicable section of the audio power amplifier circuit. Such a shock sound is not only considerably offensive to the ear and uncomfortable, but also sometimes damages the speaker.
In order to prevent such a pop sound, mute control is conventionally executed to forcibly stop signal transmission in the audio power amplifier during a time period starting from a start time when a power is supplied or a standby mode is terminated to a termination time when a power supply of the amplifier is sufficiently powered up and running. Another conventional approach is to slow down the change in voltage by employing a delay circuit formed from a capacitor and a resistor as shown in FIG. 10.
In other instances, a conventional audio power amplifier circuit does not take any countermeasures against the pop sound, and simply includes a power amplifier AMP1 connected to a differential amplifier circuit provided in an input stage. An audio signal IN is input to an inversion input terminal (i.e., a minus terminal) of the power amplifier AMP1 via a resistor R11. A feedback resistor R12 is connected between the output and the inversion input terminal of the power amplifier AMP1. A gain of the power amplifier AMP1 is determined by a ratio between the resistors R11 and R12. A reference voltage Vs is supplied to a non-inversion input terminal (i.e., a plus terminal) of the power amplifier AMP1 via a voltage follower AMP2. The output voltage SGout of the voltage follower AMP2 is utilized as a signal ground for an audio signal (hereinafter referred to as a signal GND or SG). A capacitor C12 is connected to stabilize the signal GND voltage between a signal GND (SG) terminal and ground.
A speaker is connected to the output terminal of the power amplifier AMP1 via a capacitor C11 that filters out a direct current component. A pop sound is likely generated when a power is supplied or a standby mode is terminated in the audio power amplifier circuit, because the signal GND voltage SGout quickly increases as shown by a dashed line in FIG. 12. A countermeasure can be taken to suppress the pop sound, as shown in FIG. 11. Specifically, the reference voltage Vs of FIG. 10 is replaced with a pair of resistors R13 and R14 and a capacitor C13. Thus, a voltage of a non-inversion input terminal of a voltage follower AMP2 and an output voltage SGout can be modified to slowly increase as shown by a dotted line in FIG. 12. As a result, the pop sound is reduced.
Further, Japanese Laid Open patent Application No. 10-261921 describes still another conventional technology directed to the same goal. Specifically, a power supply can indirectly be controlled to start and stop, by using a standby set signal to suppress a sharp transient change, so as to avoid uncomfortable pop sound while predictably avoiding breakdown such as caused by wiring short or the like.
However, the circuit of FIG. 11 requires a significantly large size capacitor C13 in order to suppress the pop sound to an insignificant level, and the capacitor C13 cannot be integrated on an IC, resulting in external attachment. Thus, when the capacitor C13 is employed in a small instrument such as a mobile phone, a headphone stereo, etc., largeness of the capacitor C13 impedes downsizing.
Further, in order to reduce the pop sound to such a level with the circuit of FIG. 11, it takes a long time (e.g. time elapsing T) from when a power is supplied or a standby mode is terminated to when an instrument becomes operable. On the other hand, if the capacitor C13 is downsized to reduce the time period before the operable condition, the pop sound is insufficiently suppressed, and is offensive to the ear.
Such a sound is now briefly discussed. In general, a sound comfortable to hear has a relatively low frequency, and can be heard if sound waves having different frequencies are superimposed in which one of them is a multiple or a simple integral ratio to the other. For example, a rale located at a center of a fingerboard of piano is generally tuned to approximately 442 Hz while a low rale lower by one octave is tuned to approximately 221 Hz. A high rale, on the other hand, one octave higher than the rale is tuned to approximately 884 Hz. When those rales are simultaneously hit, a considerably harmonious sound is generated because of superimposition of integral multiple sounds of the lowest rale as a reference.
In contrast, sound offensive to the ear, i.e., uncomfortable sound, can be heard when having a higher frequency. The same occurs when waves of different frequencies are intricately superimposed. For example, when a large number of fingerboards of piano are simultaneously hit at random, a ratio between respective frequencies is generally not a multiple or simple, thereby generating an uncomfortable sound. In this respect, if a sound quality of the pop sound is changed by either lowering a frequency of a sound wave or omitting sound waves having prescribed frequency components, uncomfortable pop sound can be suppressed.

System, circuit, and amplifier for reducing pop sound


The method is provided for operating a pump unit with a centrifugal pump which is driven by an electric motor and which comprises a rotor running in a split tube. The rotor space is separated with respect to the stator in a fluid-tight manner. On running the motor to its operational rotational speed the fluid located in the rotor space due to the increasing rotational speed evaporates and is removed so that the motor finally functions as a dry-runner.

The invention relates to a system and method for operating a pump.
Centrifugal pump units of a smaller or average power which today are part of the state of the art are usually designed as wet runners, i.e. they comprise a split tube which seals the rotor space with respect to the stator space, in particular, from the penetration of delivery fluid. The delivery fluid located in the rotor space in particular also serves for the lubrication of the bearings carrying the rotor shaft. The pumps of this construction type have proven themselves since they do not require any seal to the region of the movable parts, the rotor space may thus be conductingly connected to the pump space.
On the other hand, from the state of the art it is also known to apply dry runners, i.e., to seal the shaft carrying the pump impeller with respect to the motor. In order here to seal the rotor space with respect to the delivery fluid in a reliable manner and over a long time, one requires complicated sealing designs which are expensive and are often prone to wear.
Although the dry runners are basically superior to the wet runners with regard to efficiency since the distance between the rotor and the stator may be reduced and the magnetic field between these components is not weakened by the split tube, the extra expense for seals and the maintenance which is also required for long-term operation is so large that at least with small or average construction sizes one almost exclusively uses wet running motors. Otherwise one must ensure the permanent lubrication of the bearing.
In order to increase the hydraulic power of such centrifugal pumps and their efficiency, it is known to allocate a frequency converter to the unit, which is connected in front of the electric motor and permits a practically infinitely high rotational speed of the motor independently of the mains frequency and voltage. With an increasing rotational speed however the fluid friction between the rotor and split tube becomes noticeable so that with this construction type an increase in the rotational speed beyond certain limits is not very useful.

Pump unit and method for operating a pump unit


The present invention provides a method of synthesizing genes encoding unique HIV-1 and HIV-2 envelope proteins and their fragments, thereby allowing overexpression of these proteins in E. coli. The HIV envelope proteins and their fragments have been expressed at high levels as individual proteins or in fusion with other proteins. The HIV envelope proteins thus expressed in E. coli can be effectively used for the detection of exposure to HIV as well as the discrimination of HIV-1 and HIV-2.

The present invention relates to recombinant HIV (Human Immunodeficiency Virus) antigens. Recombinant antigens derived from the molecular cloning and expression in a heterologous expression system of the synthetic DNA sequences of the various HIV antigens can be used as reagents for the detection of antibodies and antigen in body fluids from individuals exposed to various HIV isolates.
The nucleotide sequence of the proviral genome has been determined for several HIV isolates, including HIV-1 strains HTLV-III (Ratner et al., Nature (1985) 313:277); ARV-2 (Sanchez-Pescador et al., Science (1985) 227:484); LAV (Wain-Hobson et al., Cell (1985) 40:9); and CDC-451 (Desai et al., Proc. Natl. Acad. Sci. USA (1986) 83:8380). The nucleotide sequence of the HIV-2 ROD isolate was reported by Guyader et al. (Nature (1987) 326:662).
HIV antigens have been obtained from the virus grown in tissue culture, or from a molecularly cloned genomic fragment expressed in heterologous hosts such as Escherichia coli. The tissue culture derived virus involves the cumbersome and often difficult process of growing virus infected cells in stringent sterile conditions. Further, the virus derived from tissue culture is infectious, and, therefore is hazardous to the health of individuals involved in propagation and purification. The expression of molecularly cloned HIV genomic fragments overcomes the biohazard problem. Generally, an HIV genomic fragment from a single HIV isolate with mammalian codons is expressed in a heterologous system, such as, bacteria or yeast, and is limited to the use of available restriction sites present in the viral genome for cloning and expression.
It has been difficult to obtain expression in heterologous systems of some of the HIV proteins, such as the HIV-1 envelope antigen gp41. Several researchers have tried deleting the hydrophobic regions of the HIV-1 gp41 to increase expression levels. UK Patent Application GB 2188639 discloses an HTLV-III gag/env gene protein wherein the env fragment of the DNA sequence deleted codons corresponds to the first hydrophobic region of the gp41 protein. U.S. Pat. No. 4,753,873 discloses a peptide fragment that is encoded by a nucleotide sequence wherein the nucleotides coding for a first and second hydrophobic region of HTLV-III gp41 are deleted.
Poor expression can be the result of many factors, including the specific nucleic acid sequence of the gene to be expressed, the fact that the mammalian codons of the gene sequence to be expressed may not be efficiently transcribed and translated in a particular heterologous system, and the secondary structure of the transcribed messenger RNA. The use of synthetic DNA fragments can increase expression in heterologous systems.

Synthetic DNA derived recombinant HIV antigens


A vehicle body (1) having a central cell (2) made of composite materials; a front auxiliary frame (3) anchored to the front end of the central cell (2); and a rear auxiliary frame (4) anchored to the rear end of the central cell (2); the front auxiliary frame (3) and the rear auxiliary frame (4) dissipated by the vehicle in the event of collision, without directly involving the central cell (2).

As is known, high-performance, central-engine vehicle bodies normally comprise a supporting structure made of composite material and only involving the front and central part of the vehicle where the passenger compartment is formed; and the engine block which projects from the rear end of the supporting structure.
The front suspensions and all the other front and central component parts of the vehicle, including the body panels, are variously fixed to the composite material supporting structure, while the rear suspensions, transmission, rear differential, and all the other rear component parts of the vehicle, including the body panels, are fixed directly to the engine block, which in turn is fixed rigidly to the composite-material supporting structure by means of bolts or similar.
Though ensuring a high degree of rigidity and passenger safety, bodies of the above type have the major drawback of being practically impossible to repair in the event of collision. That is, the mechanical stress produced on impact is transmitted directly to the composite-material supporting structure, which is extremely rigid and lightweight, but also only deformable at the expense of being irreparably impaired structurally.
In the event of impact, in fact, the composite-material supporting structure collapses and disintegrates irreparably, so that,to repair the vehicle, the entire supporting structure must be replaced at exorbitant cost.
Another drawback of the above solution is that the engine block must be fixable firmly to the composite-material supporting structure, and must have a torsional and flexural rigidity comparable with that of the supporting structure, thus greatly increasing manufacturing cost as compared with a conventional engine block, which on average is also lighter than a structural engine block.


A method and apparatus for synthesizing high-frequency signals, such as wireless communication signals, includes a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that has a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired frequency output. The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired frequency output. The continuously variable capacitance may be formed by using a plurality of separate capacitance circuits. The individual capacitance circuits may include two capacitors coupled to a variable resistance element. The variable resistance element may be a transistor controlled by an analog control voltage. The total capacitance of the continuously variable capacitance may be substantially linear with respect to the phase of the VCO output while the individual capacitance circuits exhibit nonlinear behavior.

The present invention relates generally to the synthesis of high-frequency signals. More particularly, the present invention relates to the synthesis of high-frequency local oscillator signals for wireless communication applications.
Wireless communication systems typically require frequency synthesis in both the receive path circuitry and the transmit path circuitry. For example, cellular phone standards in the United States and Europe define a cellular telephone system with communication centered in two frequency bands at about 900 MHz and 1800 MHz. For example, United States cellular phone standards include (1) the AMPS (analog), IS-54 (analog/digital), and IS-95 (analog/digital) standards in the 900 MHz frequency band, and (2) PCS (digital) standards in the 1800 MHz range. European cellular phone standards include (1) the TACS (analog) and GSM (digital) standards in the 900 MHz frequency band, and (2) the DCS1800 (digital) standard in the 1800 MHz range. A dual band cellular phone is capable of operating in both the 900 MHz frequency band and the 1800 MHz frequency band.
Within the frequency bands, the cellular standards define systems in which base station units and mobile units communicate through multiple channels, such as 30 kHz (IS-54) or 200 kHz (GSM) wide channels. For example, with the IS-54 standard, approximately 800 channels are used for transmitting information from the base station to the mobile unit, and another approximately 800 channels are used for transmitting information from the mobile unit to the base station. A frequency band of 869 MHz-894 MHz and a frequency band of 824 MHz-849 MHz are reserved for these channels, respectively. Because the mobile unit must be capable of transmitting and receiving on any of the channels for the standard within which it is operating, a frequency synthesizer must be provided to create accurate frequency signals in increments of the particular channel widths, such as for example 30 kHz increments in the 800-900 MHz region.
Phase-locked loop (PLL) circuits including voltage controlled oscillators (VCOs) are often used in mobile unit applications to produce the desired output frequency (fOUT). The output frequency may be made programmable by utilizing an output frequency feedback divider (÷N) and a reference divider (÷R) for an input reference frequency (fREF). The output frequency produced is a function of the values selected for xe2x80x9cNxe2x80x9d and xe2x80x9cRxe2x80x9d in the divider circuits, such that fOUT=N(fREF/R). The PLL circuitry typically utilizes a phase detector to monitor phase differences (xcex94xcex8) between the divided reference frequency (fREF/R) and the divided output frequency (fOUT/N) to drive a charge pump. The charge pump delivers packets of charge proportional to the phase difference (xcex94xcex8) to a loop filter. The loop filter outputs a voltage that is connected to the VCO to control its output frequency. The action of this feedback loop attempts to drive the phase difference (xcex94xcex8) to zero (or at least to a constant value) to provide a stable and programmable output frequency.
The values for the reference frequency and the divider circuits may be chosen depending upon the standard under which the mobile unit is operating. For example, within the United States IS-54 system, a PLL could be built such that fREF/R=30 kHz and such that N is on the order of 30,000. The output frequency, therefore, could then be set in 30 kHz increments to frequencies in the 900 MHz frequency band. Similarly, within the European GSM system, a PLL could be built such that fREF/R=200 kHz and such that N is on the order of 4,500. The output frequency, therefore, could then be set in 200 kHz increments to frequencies in the 900 MHz frequency band.
The performance of the communication system, however, is critically dependent on the purity of the synthesized high-frequency output signals. For signal reception, impure frequency sources result in mixing of undesired channels into the desired channel signal. For signal transmission, impure frequency sources create interference in neighboring channels. A frequency synthesizer, therefore, must typically meet very stringent requirements for spectral purity. The level of spectral purity required in cellular telephone applications makes the design of a PLL synthesizer solution and, in particular, the design of a VCO within a PLL synthesizer solution quite demanding.
Three types of spectral impurity will typically occur in VCO circuits that are used in PLL implementations for frequency synthesis: harmonic distortion terms associated with output frequency, spurious tones near the output frequency, and phase noise centered on the output frequency. Generally, harmonic distortion terms are not too troublesome because they occur far from the desired fundamental and their effects may be eliminated in cellular phone circuitry external to the frequency synthesizer. Spurious tones, however, often fall close to the fundamental. In particular, spurious tones at frequencies of xc2x1fREF/R from the output frequency (fOUT) are often found in the output frequency spectrum. These are called reference tones. Spurious tones, including reference tones, may be required by a cellular phone application to be less than about xe2x88x9270 dBc, while harmonic distortion terms may only be required to be less than about xe2x88x9220 dBc. It is noted that the xe2x80x9ccxe2x80x9d indicates the quantity as measured relative to the power of the xe2x80x9ccarrierxe2x80x9d frequency, which is the output frequency.
Phase noise is undesired energy spread continuously in the vicinity of the output frequency, invariably possessing a higher power density at frequencies closer to the fundamental of the output frequency. Phase noise is often expressed as dBc/Hz or dBc/Hz. Phase noise is often the most damaging of the three to the spectral purity of the output frequency. Because of the effect phase noise has on system performance, a typical cellular application might require the frequency synthesizer to produce an output frequency having phase noise of less than about xe2x88x92110 dBc/Hz at 100 kHz from the output frequency.
Because the phase noise specifications are so stringent in cellular phone applications, the VCOs used in cellular phone PLL synthesizer solutions are typically based on some resonant structure. Ceramic resonators and LC tank circuits are common examples. While details in the implementation of LC tank oscillators differ, the general resonant structure includes an inductor (L) connected in parallel with a fixed capacitor (C) and a variable capacitor (CX). In the absence of any losses, energy would slosh between the capacitors and the inductor at a frequency fOUT=(xc2xdxcfx80)[L(C+CX)]xe2x88x921/2. Because energy will be dissipated in any real oscillator, power in the form of a negative conductance source, such as an amplifier, is applied to maintain the oscillation. It is often the case that the series resistance of the inductor is the dominant loss mechanism in an LC tank oscillator, although other losses typically exist.
While it is highly desirable to integrate the VCO with the other components of the PLL onto a single integrated circuit for cost, size, power dissipation, and performance considerations, barriers to integration exist. One of the more significant barriers is the lack of precision in the values of the inductors and capacitors used in the LC tank of the PLL. This tolerance problem typically forces most PLL synthesizer implementations to modify the inductor or capacitor values during production, for example, by laser trimming. Further complicating integration is the difficulty in integrating an inductor with a low series resistance and a capacitor with a reasonably high value and with low loss and low parasitic characteristics. In integrating capacitance values, a significant problem is the high value of a typical loop filter (LF) capacitor component, which is often on the order of 1-10 xcexcF. Another significant problem is the absence of a variable capacitance (CX) component that possesses a highly-variable voltage-controlled capacitance that is not also a high loss component that causes phase noise. To provide this variable capacitance (CX) component, a high-precision reverse-biased diode or varactor is typically utilized. However, such high-performance varactors require special processing and, therefore, have not been subject to integration with the rest of the PLL circuitry. In short, although integration onto a single integrated circuit of a PLL implementation for synthesizing high-frequency signals is desirable for a commercial cellular phone application, integration has yet to be satisfactorily achieved.
In accordance with the present invention, a method and apparatus for synthesizing high-frequency signals is disclosed that overcomes the integration problem associated with prior implementations and meets the demanding phase noise and other impurity requirements. The present invention achieves this advantageous result by implementing a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that includes a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired output frequency. The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired output frequency and to provide compensation for post-calibration drift of the PLL circuitry. The present invention avoids the need for a traditional varactor implementation in the VCO, for a traditional large capacitor component in the loop filter, and for component trimming during processing and thereby provides a high-frequency synthesizer that may be fully integrated on a single chip except for an external inductor.
In one embodiment, a wireless communication frequency synthesizer having at least one variable frequency output, the output frequency varying as a capacitance within the synthesizer varies, is provided. The synthesizer may include a variable capacitance circuit integrated within the frequency synthesizer. The variable capacitance circuit may comprise a first capacitor and a second capacitor coupled in series between a first node and a second node, a control node coupled between the first and second capacitors, and a variable resistance element coupled between the control node and the second node. The synthesize may also include a variable control signal coupled to the variable resistance element.
In another embodiment, a method of operating a wireless communication frequency synthesizer may comprise providing a capacitance circuit integrated within the frequency synthesizer, the capacitance circuit comprising a first capacitor and a second capacitor coupled in series between a first node and a second node, a third node being between the first and second capacitors. The method may further include providing a variable resistance element coupled to the third node, generating a variable control signal, and controlling the resistance of the variable resistance element with the variable control signal to vary the capacitance of the capacitor circuit.
In another embodiment, a wireless communication frequency synthesizer having at least one variable frequency output, the output frequency varying as a capacitance within the synthesizer varies may comprise a variable capacitance circuit integrated within the frequency synthesizer. The variable capacitance circuit may comprise a first capacitor coupled between a first node and a second node, a control node coupled between the first and second nodes, and a variable resistance element coupled between the control node and the second node. The synthesizer may also include an analog variable control signal coupled to the variable resistance element.
In still another embodiment, a method of operating a wireless communication frequency synthesizer is provided. The method includes providing a capacitance circuit integrated within the frequency synthesizer, the capacitance circuit comprising a first capacitor coupled between a first node and a second node, a third node being between the first and second nodes. The method also includes providing a variable resistance element coupled to the third node, generating a variable analog control signal, and controlling the resistance of the variable resistance element with the variable analog control signal to vary the capacitance of the capacitance circuit.
A wireless communication frequency synthesizer having at least one variable frequency output, the output frequency varying as a capacitance within the synthesizer varies is also provided. The synthesizer may comprise a frequency output, and a substantially linear variable capacitance circuit integrated within the frequency synthesizer. The variable capacitance circuit may comprise a plurality of nonlinear capacitance circuits, at least some of the nonlinear capacitance circuits controlled by at least one variable control signal. The substantially linear variable capacitance circuit may have a substantially linear relationship between the phase of the frequency output and the capacitance of the variable capacitance circuit.
In still another embodiment, a method of operating a wireless communication frequency synthesizer is provided. The method comprises providing an integrated variable capacitance circuitry, the variable capacitance circuitry formed from a plurality of capacitance circuits, adjusting a capacitance of each of the plurality of capacitance circuits in a nonlinear manner, and adjusting the output frequency of the synthesizer by varying a total capacitance of the variable capacitance circuitry in a substantially linear manner.

Method and apparatus for generating a variable capacitance for synthesizing high-frequency signals for wireless communications


The chip antenna shown is provided with two chip antenna elements (the 1st chip antenna element 4, the 2nd chip antenna element 2). These chip antenna elements have the 1st magnetic base 10 and the 2nd magnetic base 8, and linear conductors 7 and 5 formed in the core, respectively. Magnetic base 10 and magnetic base 8 are separated. In the 1st chip antenna element 4, linear conductor 7 formed in the core of the 1st magnetic base 10 was formed to the end face of this magnetic base, and the end has protruded from said end face. On the other hand, in the 2nd chip antenna element 2, linear conductor 5 formed in the core of the 2nd magnetic base 8 has penetrated magnetic base 8. Furthermore, conductor 7 in the 1st chip antenna element and conductor 5 in the 2nd chip antenna element are electrically connected mutually in series by connection conductors 13 arranged among these chip antenna elements.

1. Field of the Invention
This invention relates to a chip antenna used for electronic equipment with a communication function, such as cellular phone, personal digital assistant equipment. Furthermore, this invention relates to an antenna system and communication equipment using this chip antenna.
2. Description of the Related Art
The frequency range in communication equipment, such as a cellular phone and wireless LAN, ranges from hundreds of MHz to several GHz. It is required for this frequency range to be wide and for the efficiency in this range to be high. Therefore, the antenna used for this communication equipment also needs to be high gain in this frequency range, it is needed to be small and to be thin also. In the ground digital broadcasting started in recent years, the frequency range in the television broadcasting in Japan is 470 MHz-770 MHz, for example. When it corresponds to all the channels, it is required that this antenna can receive such a wide frequency range. Conventionally, a chip antenna using dielectric ceramics as a small antenna suitable for mobile communications has been offered (for example, see Japanese Patent No. H10-145 123). When setting frequency constant, miniaturization of a chip antenna can be attained by using dielectrics with a higher dielectric constant. In art given in this document, this wavelength is shortened by providing a meander shaped electrode. Moreover, the antenna aiming at miniaturization is also proposed by shortening a wavelength 1/(εr·μr)1/2 times using the magnetic material with large relative permittivity εr and large relative magnetic permeability μr (for example, see Japanese Patent No. S49-40046).
Moreover, for example with a small liquid crystal television, the whip antenna using the metal stick is generally used as a receiving antenna currently used for television or radio. This system is beginning to be used also for the cellular phone with television function. Furthermore, the electric wire which is a part of earphones used with a cellular phone, may be used as a receiving antenna of radio or television.
Although the above-mentioned dielectric chip antenna is advantageous for a miniaturization and thinning, there are the following problems to making bandwidth of a frequency range wide. For example, when using a helical-type radiation electrode as an electrode, if a number of turns increases, the capacitance between electric wires will increase and Q value will become high. Therefore, bandwidth becomes narrow and it becomes difficult to apply to uses, such as ground digital broadcasting as which wide bandwidth is required.
Making bandwidth wide and a miniaturization, are possible, with the above-mentioned magnetic material chip antenna. However, the mounting space for electronic parts in communication equipment, especially in portable communication equipment, is restricted. Therefore, it is further necessary to reduce the mounting space which an antenna occupies. However, this chip antenna is generally making rectangular parallelepiped shape, and its size is also large compared with other electronic parts. Therefore, it may be unable to be mounted efficiently spatially.
For example, generally the case of a cellular phone has curved surface shape. Therefore, when arranging the chip antenna of rectangular parallelepiped shape at the end of a case, a spatial loss may arise.
So, this invention aims at offering a chip antenna suitable for efficient mounting within communication equipment in this invention. Also it aims at offering the antenna system and communication equipment using this chip antenna.

Chip antenna, an antenna device, and a communication equipment


A dynamic selection of a communications link between a storage controller and one of a plurality of storage servers is provided so as to enhance the performance of the storage system. The storage system includes a plurality of storage devices, a corresponding plurality of virtual storage controllers coupled to the storage devices and a virtual storage controller. The virtual storage controller includes a host interface, a server interface, a stored table and a processing unit. The stored table includes a list identifying the active links between the server interface and each virtual storage server and, for each active link, a corresponding performance value. The processing unit is programmed to receive from a host a request for a storage operation on selected data, determine which active link has the most favorable performance value and direct that the requested storage operation be performed by the virtual storage server coupled to the virtual storage controller over the active link having the most favorable performance value.

Early computer data storage systems included one host device, one storage device (such as a hard disk drive, tape drive or an optical drive) and a storage controller to manage the transfer of data between the host and the storage device. The use of a single storage device eventually evolved into consolidating several storage devices (such as tape drives) into an automated library and many (sometimes hundreds or even thousands) of pieces of media (such as tape cartridges) retrievable by mechanical means for loading into one of the storage devices. More recent innovations permit more than one storage library to be attached to a host (or to more than one host) through a storage controller and multiple storage servers in such a fashion so as to be transparent to the host. Thus, regardless of the physical configuration of a storage system, the host logically "sees" only a single storage device through a single storage server. The storage servers in such a system are referred to as "virtual" storage servers (virtual tape servers in the case of tape-based systems) and the storage controllers are referred to as "virtual" storage controllers (virtual tape controllers in the case of tape-based systems).
Even more recently, IBM Corporation has developed a "Peer-to-Peer Virtual Tape Server". Two (or possibly more) virtual tape server (VTSs) may be geographically separated (although they are not required to be) and are connectable to an S/390® host processor through a virtual tape controller ("VTC"), such as an IBM® Model AXO. VTC to VTS connections may be over enterprise system connection (ESCON®) or fiber connection (FICON TM) communication links, with or without channel extenders.
In a typical operation, a host sends a request to the controller for access to particular stored data. If the data resides in a server cache, the read or write operation is performed using the cached data. Otherwise, the data is retrieved from the storage device by the server and then the operation is performed.
Performance may degrade as the distance between the VTC and a VTS (and its corresponding library) increases. Therefore, when the distances from the VTC to one VTS is significantly greater than the distance to another VTS, it may be desirable to establish a preference for the closer VTS and library in an attempt to maximize performance. Data operations will be sent to the preferred VTS by default, absent the existence of other considerations, such as a backlog in the preferred server.
Each link between the VTC and a VTS may be characterized by the type of communications link connecting the two, the presence and type of any extender and the length of the link. The performance of a link is affected by each of these factors. For example, an ESCON link which is five kilometers (5 km) long will be faster than an ESCON link which is ten kilometers (10 km) long, other factors being equal. However, if the requested data resides in cache in the VTS attached through the longer link, the actual operation time may be faster through the VTS which is farther away from the VTC than if the data must be retrieved into the other, closer link.
Finally, during normal operations a closer VTS may have accumulated a backlog of host job requests and consequently that VTS may take longer to fulfill new requests than one which is farther from the VTC but has less of a backlog, regardless of the state of the cache.
Thus, there are significant interrelated variables which affect the overall performance of the storage system and there remains a need for improved workload allocation among storage servers in a storage system.

Autonomic performance tuning of a distributed virtual storage server

International Business Machines Corporation


An automatic machine for hot dipping galvanization has lower and upper frames to support a slide, an elevator and a control device. The slide consists of two sets of sprocket wheels, each having two sprocket wheels installed at respective ends of each frame controlling a plurality of guide rails via link belts to slide along two slideways. The elevator consists of an elongated elevator hanging on top of the lower frame by means of four guide supports which each have one end connected to the elevator and the other end to a U-shaped rod. Two arcuate plates extending outwards from respective ends of the elevator carry articles to be galvanized into the zinc bath and galvanized articles out of the zinc bath. The control device consists of a central processing unit which controls the entire movement, a motor which controls the slide, and a cylinder which controls the elevator.

1. Field of the Invention
This invention relates to an automatic machine for hot dipping galvanization, more particularly to a machine to galvanize small metallic parts in a zinc bath for a predetermined time and to pull the parts outwards from the zinc bath with an automatic system.
2. Related Prior Art
Galvanization of metallic parts is one method to provide them with a protective layer which prevents the parts from corrosion or easily cracking.
Galvanization has been adapted by industry as an anti-corrosive method for a long time. There are many processing steps in galvanization which includes filling, hot dipping, vibration, cleaning and cooling. Among these steps, hot dipping is an important step which requires precise estimation of dipping time which is determined by a worker's experience according to the current procedure and mistakes happen once in awhile. Moreover, zinc disperses poisonous gas in a high temperature atmosphere which is dangerous to the human body if inhaled.
The inventor, in view of this, has invented this invention which is operated automatically.

Automatic machine for hot dipping galvanization


An earth-boring bit has a seal assembly with a seal face having a DLC coating. The seal assembly locates between a bearing pin and a cone of the bit. The seal assembly has at least one rigid ring that rotates against a mating surface. The DLC coating is diamond-like carbon that may be coated by different processes onto either the ring, the mating surface, or both.

In drilling boreholes in earthen formations by the rotary method, earth-boring bits typically employ at least one rolling cone cutter, rotatably mounted thereon. The bit is secured to the lower end of a drillstring that is rotated from the surface or by downhole motors. The cutters mounted on the bit roll and slide upon the bottom of the borehole as the drillstring is rotated, thereby engaging and disintegrating the formation material. The rolling cutters are provided with teeth that are forced to penetrate and gouge the bottom of the borehole by weight from the drillstring.
As the cutters roll and slide along the bottom of the borehole, the cutters, and the shafts on which they are rotatably mounted, are subjected to large static loads from the weight on the bit, and large transient or shock loads encountered as the cutters roll and slide along the uneven surface of the bottom of the borehole. Thus, most earth-boring bits are provided with precision-formed journal bearings and bearing surfaces, as well as sealed lubrication systems to increase drilling life of bits. The lubrication systems typically are sealed to avoid lubricant loss and to prevent contamination of the bearings by foreign matter such as abrasive particles encountered in the borehole. A pressure compensator system minimizes pressure differential across the seal so that the lubricant pressure is equal to or slightly greater than the hydrostatic pressure in the annular space between the bit and the sidewall of the borehole.
A major advance in earth-boring bit seal technology occurred with the introduction of a successful rigid face seal. Rigid face seals are known in several configurations, but typically comprise at least one rigid ring, having a precision seal face ground or lapped thereon, confined in a groove near the base of the shaft on which the cutter is rotated, and an energizer member, which urges the seal face of the rigid ring into sealing engagement with a second seal face. Thus, the seal faces mate and rotate relative to each other to provide a sealing interface between the rolling cutter and the shaft on which it is mounted.
The combination of the energizer member and rigid ring permits the seal assembly to move slightly to minimize pressure fluctuations in the lubricant, and to prevent extrusion of the energizer past the cutter and bearing shaft, which can result in sudden and almost total lubricant loss. U.S. Pat. No. 4,516,641, to Burr; U.S. Pat. No. 4,666,001, to Burr; U.S. Pat. No. 4,753,304, to Kelly; U.S. Pat. No. 4,923,020 to Kelly; and U.S. Pat. No. 6,142,249 to Zahradnik et al are examples of rigid face seals for use in earth-boring bits. Rigid face seals substantially improve the drilling life of earth-boring bits of the rolling cutter variety. Earth-boring bits with rigid face seals frequently retain lubricant and thus operate efficiently longer than prior-art bits.
Because the seal faces of rigid face seals are in constant contact and slide relative to each other, the dominant mode of failure of the seals is wear. Eventually, the seal faces become pitted and the coefficient of friction between the seal faces increases, leading to increased operating temperatures, reduction in seal efficiency, and eventual seal failure, which ultimately result in bit failure. In an effort to minimize seal wear, seal rings of prior-art rigid face seals are constructed of tool steels such as 440C stainless steel, or hardenable alloys such as STELLITE. Use of these materials in rigid face seals lengthens the drilling life of bits, but leaves room for improvement of the drilling longevity of rigid face seals, and thus earth-boring bits.
Very hard, wear-resistant layers and coatings have been developed in general, such as those employing diamond. These coatings, however, generally need to be applied at high temperatures and high pressures. The coatings are applied after the steel ring has been hardened. If the high temperatures exceed the lowest transformation temperature of the steel of the ring, such as the temperature at which the steel ring has been tempered, this would adversely affect the properties of the seal ring.
U.S. Pat. No. 6,209,185 to Scott discloses applying a diamond layer to substrate, then attaching the diamond layer to the rigid ring. This avoids having to heat the hardened ring beyond its lowest transformation temperature, but it does require attachment by brazing, epoxy or the like. U.S. Pat. No. 6,045,029 to Scott discloses forming a diamond layer directly on a rigid seal ring by a process that is accomplished at a temperature lower than the lowest transformation temperature of the metal of the seal ring. This may be done in an amorphic diamond process or by forming the diamond layer separately and attaching it to the rigid ring of the seal.

DLC coating for earth-boring bit seal ring


A method and system are disclosed for designing a complex integrated electronic circuit architecture including a plurality of circuit portions integrated into a single chip structure. The method includes providing at least one library of cells with a variable channel length L; creating a layout of an integrated circuit using the cells with an initial channel length L; performing a timing analysis of the integrated circuit to analyze more and less critical paths by evaluating respective path delays; selecting a set of less critical paths to be modified; evaluating the leakage currents of the less critical paths of the selected set; and modifying the variable channel length L of the cells which are involved in the less critical paths of the selected set on the basis of the corresponding evaluated leakage current and the respective path delays, whereby a modified integrated circuit with a reduced circuit leakage current is obtained.

Several techniques have been used to address the leakage problem; for instance some techniques propose using only high performance LVT circuits in the critical path and slower circuits, such as HVT device, with less leakage elsewhere on the chip. Circuit libraries are available in several variations of VTs, which can be mixed and matched throughout the chip. Very complex chip methodologies are used to determine where a HVT circuit should be used in place of a Low VT (LVT) circuit to increase performance.
In one prior approach, a method and system for determining optimal delay allocation to data path blocks is based on area-delay and power-delay curves. In particular this method, system and computer program product automatically determine optimal design parameters of a subsystem to meet design constraints. The subsystem includes a plurality of circuits. The optimal design parameters are determined by performing a parameter-delay curve optimization of the subsystem design parameters.
Another solution is, in a standby state, the use of substrate bias to reduce leakage. In functional mode there is no performance degradation. Dual Threshold voltage is a well-known approach to reduce leakage by partitioning the circuit based on the speed/performance requirements.
In connection with such a Dual Threshold Voltages strategy, another approach for power management includes first synthesis step performed using high-Vt transistor, while low-Vt are used to close the timing constraints.
We will make hereinafter more specific reference to the SYNOPSYS tools that are known for reducing power at an average of 10 to 20 percent during gate-level optimization.
Based on user's timing, power and area constraints, these tools measures trade-offs between positive timing slacks, area and power and then deliver the lowest power consuming design that meets timing constraints, while maintaining the area limit when specified by the user. Power Compiler performs automatic clock gating at the Register Transfer Level (RTL) and it also supports multi-threshold libraries for automatic leakage optimization. Incremental synthesis allows starting with all high threshold voltage cells and substituting a small percentage of them with low threshold voltage ones for critical paths. After place and route, the substitution of high Vt cells with low Vt ones after paths are analyzed with precise timing information is implemented.
A further tool does multi-Vt leakage power optimization. Moreover, these tools are capable of minimizing the leakage during the synthesis step through the clock gating approach and, following P&R, the multi-Vt optimization is done.
Another approach proposed by tool vendors is based on the fact that the leakage current of a gate mainly depends on the state of the input signals. If a vector can be found that minimizes the leakage current, then this vector can be applied when the circuit is idle. However, it's quite a hard job to find such an optimal vector as the logic depth increases.
A SIGNOFF static timing analysis (STA) is performed after the place and route of the block. The main issues with this approach are related to critical paths at high frequency, in the range of 1 GHz, where the timing closure is a must despite the power consumption, leakage and area. On the other end, on paths at lower frequencies where the positive slacks are quite large, it is possible to reduce the leakage by slowing down some data delays thus losing timing margin but still maintaining require specifications.
All the known methodologies above described, whilst enabling a decrease of power consumption, nevertheless have a recognized drawback not yet overcome, that the obtained decrease of leakage often affects the ability to achieve or respect the timing requirements.
In view of the above-outlined drawback of the state of the art, there is the need of providing a method and system to implement application specific integrated circuit (ASIC) designs in order to reduce leakage without affecting the timing requirements.

Method and system for designing semiconductor circuit devices to reduce static power consumption


A method and apparatus for detecting concealed items on or in an object by utilizing a low Z material panel. The object to be scanned is located between an x-ray detector and the low Z material panel. The method includes producing a pencil beam of x-rays from an x-ray source directed toward the object, scanning the beam of x-rays over the object, and detecting x-rays scattered from the beam of x-rays as a result of interacting with the object and the low Z material panel. The apparatus includes an x-ray source to produce a pencil beam of x-rays directed toward the object, a scanner to scan the beam of x-rays over the object, and the detector to detect x-rays scattered from the beam of x-rays as a result of interacting with the object and the low Z material panel.

Security systems are limited in their ability to detect contraband, weapons, explosives, and other dangerous objects concealed under a person's clothing or in an object, such as a box or bag. Metal detectors and chemical sniffers are commonly used for the detection of large metal objects and some kinds of explosives, however, a wide range of dangerous objects exist that cannot be detected with these devices. Plastic and ceramic weapons developed by modern technology increase the types of non-metallic objects that security personnel are required to detect. The alternative of manual searching of subjects is slow, inconvenient, and would not be well tolerated by the general public, especially as a standard procedure in, for example, airports.
Radiation exposure is an important consideration in x-ray concealed object detection systems. The United States National Council on Radiation Protection (NCRP), in NCRP Report No. 91, "Recommendations on Limits for Exposure to Ionizing Radiation", 1987, addresses this issue. In this report, the NCRP states that a radiation exposure of less than 1000 microRem per year in excess of environmental levels is negligible, and efforts are not warranted at reducing the level further. Persons employed in high security or secured facilities, or those who frequently travel by airlines, may be subjected to many hundred security examinations per year. A yearly radiation exposure limit of 1000 microRem safely permits a single scan exposure within the range of 1 to 10 microRem for the general public. In accordance with the NCRP recommendations, radiation levels significantly higher than this may present some health risk.
Known prior art x-ray systems have limitations in their design and method which prohibit them from achieving the low dose and high image quality that are prerequisites to commercial acceptance. For example, radiant energy imaging systems that detect concealed objects carried on or in an object often scan pencil beam of x-rays through the object where the beam is transmitted or absorbed depending upon the concealed object, if any. A detector may be scanned vertically behind the object in step with the pencil beam to collect the transmitted x-rays.
U.S. Pat. No. 5,181,234 (the '234 patent), herein incorporated by reference as if set forth fully herein, discloses an imaging system which does not require x-rays to be scanned through the object. The '234 patent discloses an imaging apparatus where a narrow pencil beam of x-ray radiation is scanned over the object whereby x-rays that strike low atomic number materials, such as soft tissue, are scattered (i.e. reflected) back toward the apparatus. In comparison, x-rays that strike metal are mostly absorbed and generate very little scatter. Moreover, x-rays that do not strike the object are not captured or scattered back toward the apparatus since the x-rays continue until absorbed or scattered by items further behind the object. Detectors within the apparatus capture the scattered x-rays and generate a corresponding image. For example, as shown in FIG. 1, the vast majority of the body 12 appears light, as a result of the soft tissue generating significant back scatter of x-rays. Metals such as coins in the pocket 102 and belt buckle 103 appear dark due to their absorption of the x-rays. The background 104 around the body is also dark since there is nothing to scatter the x-rays back to the detector.
As shown in FIG. 2, a potential disadvantage of this approach is the difficulty in detecting metal objects that appear in front of or against the background 104 and not in front of the body 12. FIG. 2 shows a metal handgun 106 concealed under the subject's 12 arm. The handgun 106 is virtually impossible to detect in this view since both the handgun 106 and the background 104 appear dark. People may also hang or wear contraband on their sleeves or pant legs, which would be difficult to detect since it would be against the background and appear dark.
Another potential disadvantage of the prior art is that it provides no mechanism to control the x-rays not scattered or absorbed by the object. Currently, the x-rays not scattered or absorbed by the object continue until absorbed or scattered by other items beyond the object. Thus, no objects or persons should be within six to fifteen feet of the apparatus otherwise the person or object will be unnecessarily exposed to the x-rays and may even appear in the image.
Thus, there is a need for an apparatus that would overcome the disadvantages of prior art x-ray systems and allow for the detection of concealed objects in the same plane as the background. There is also a need for a way to control x-rays that are not scattered or absorbed by the object to protect other persons from unnecessary exposure to the x-rays and to prevent image degradation.

X-ray detector system having low Z material panel


The invention solves a problem of that sufficient adhesive intensity to satisfy recent demand for high adhesive property cannot be obtained by conventional surface treatment, and provides a method of improving adhesive property of polyimide film and achieving distinctly improved effect of adhesive property. The invention further provides novel polyimide film having improved adhesive property.. A method for improving adhesive property of polyimide film according to the present invention comprises a combination of steps of;. execution of a liquid applying process for treating polyimide film surface by exerting physical mechanical force on said film surface under the condition of that said film surface remains wet with water or organic solvent, or solution of organic solvent or aqueous solution; and execution of a surface treatment process for treating polyimide film surface by performing selected treatment among flame treatment, alkaline treatment, coupling agent treatment or surface treatment by way of projecting grinding material of fine grading onto film surface at high velocity, and said steps are performed in an arbitrary order. For example, using a surface treating device 10 shown in FIG. 1, consecutive execution of a surface treatment process for treating film surface, a liquid applying process and a drying process is realized by that polyimide film 22 is run from a feeding device 18 to a winding device 20.

The present invention relates to a method of improving adhesive property of polyimide film, more particularly, to a method of improving adhesive property of polyimide film capable of stably generating distinct adhesive property without affecting adhesive agent, and the invention further relates to polyimide film having distinct adhesive property improved by the method of improving adhesive property.
Normally, polyimide film is used for a flexible printed circuit board (FPC) after being laminated with metallic foil (mainly with copper foil) by using an adhesive agent or processed to a laminated board comprising a film layer and a metallic layer via evaporation, plating or a sputtering process. At that time polyimide film is used for a base film, however, poor adhesive property of the conventional polyimide film surface has raised a problem, and using such polyimide film causes faulty products.
One cause of poor adhesive property of polyimide film surface accounts for plane and smooth surface thereon. In detail, the polyimide film surface is smooth and plane even in the case when stabilizer and additive are mixed after producing film by casting solution and performing condensation polymerization of said solution in the process of producing film. When the film surface is smooth and plane, actual adhesive area between the film surface and adhesive agent is relatively contracted, and as a result, sufficient adhesive strength can hardly be generated.
It is scientifically known that stabilizer and additives which were mixed at the time of producing film preferentially bleed from the film surface produced by solution cast method to form "weak boundary layer" (WBL) and migration of low-molecular polymer such as oligomer as composing substance of weak boundary layer could be accelerated. It is also probable that contaminant such as oily matter generated from a film productive plant or contaminant present in the atmosphere adheres to the produced film to result in the formation of stained layer. There is such a case in which because these layers are easy to exfoliate from the film surface, in the case when adhered with adhesive agent or the like, molecular scale of film cannot be adhered firmly, and these layers become a factor to obstruct adhesive property of the film.
It is general to use polyimide film with various kinds of surface treatment given for improving adhesive property of polyimide film surface. Familiar examples of such surface treatments are flame treatment, alkaline treatment, coupling agent treatment for adhering coupling agent solution onto the film surface or sand blasting process by blasting silica sands or the like against the film surface by applying compressed air or centrifugal force.
Though operation functions of these treatments are not clarified, flame treatment is considered to improve adhesiveness of the polyimide film surface by removing evaporated or gassed WBL or stained layer on film surface and purifying film surface. Also alkaline treatment is considered to improve adhesiveness of polyimide film surface by removing WBL or stained layer from film surface with alkaline solution. Coupling agent treatment is considered to improve adhesiveness of polyimide film surface by introducing reactive radical by adhering coupling agent solution onto film surface. Sand blasting treatment is considered to improve adhesiveness of polyimide film surface by increasing adhering area between film surface and adhering agent by forming the uneven surface, and at the same time removing WBL or stained layer from said surface.
However, there has been such a problem that sufficient adhesive intensity to satisfy demand for materializing higher adhesive effect in recent years cannot fully be achieved by these conventional surface treatments.

Method of improving adhesive property of polyimide film and polymidefilm having improved adhesive property

Kanegafuchi Kagaku Kogyo Kabushiki Kaisha


One or more techniques and/or systems are disclosed for providing resource authorization to users of a distributed memory store (e.g., a distributed web-based cloud service). A session ID that identifies a location of an authorization document in a distributed memory store is used to access the authorization document, which comprises a global section with a principal ID related to a user. The user can be authorized to utilize a resource (e.g., in a distributed cloud service) if a resource section is present for the principal ID in the authorization document, and has appropriate resource data for the resource. If the resource section is not present, it can be created in the authorization document, and identified by a resource identifier. Authorization data can be loaded into the newly created resource section, and the authorization document, with the global and resource sections, is saved to a local cache for the distributed memory store.

Distributed, web-based services are typically called cloud services, and they provide shared resources, services, software and information on demand. These cloud services are typically distributed among a plurality of servers, clusters of servers, and/or datacenters comprising clusters. Users access the cloud services by accessing the Internet, and authenticating themselves to the particular service. Cloud services often need to scale to hundreds of millions of users, and billions of resources, which are typically partitioned into scale units that are capable of allowing efficient access to those resources (e.g., in datacenters, and/or clusters).
For most cloud services, a tiered approach is developed with resources spread over multiple partitioned databases installed in multiple datacenters. Efficient algorithms and addressing schemes have been developed for users to locate resources. When a user wishes to utilize a cloud service, they often authenticate to the service, such as by using a shared secret (e.g., username and password combination, or cryptographic keys, etc.). Further, the user is typically authorized to use particular services for a particular amount of time, and the authorization information can be accessed by the service to identify whether the user can utilize the resource of interest.

Distributed services authorization management


The present invention is directed to an electroconductive thick film composition comprising: (a) electroconductive metal particles selected from (1) Al, Cu, Au, Ag, Pd and Pt; (2) alloy of Al, Cu, Au, Ag, Pd and Pt; and (3) mixtures thereof; (3) glass frit wherein said glass frit is Pb-free; dispersed in (d) an organic medium, and wherein the average diameter of said electroconductive metal particles is in the range of 0.5-10.0 μm. The present invention is further directed to an electrode formed from the composition as detailed above and a semiconductor device(s) (for example, a solar cell) comprising said electrode.

The present invention can be applied to a broad range of semiconductor devices, although it is especially effective in light-receiving elements such as photodiodes and solar cells. The background of the invention is described below with reference to solar cells as a specific example of the prior art.
A conventional solar cell structure with a p-type base has a negative electrode that is typically on the front-side or sun side of the cell and a positive electrode on the back side. It is well known that radiation of an appropriate wavelength falling on a p-n junction of a semiconductor body serves as a source of external energy to generate hole-electron pairs in that body. Because of the potential difference which exists at a p-n junction, holes and electrons move across the junction in opposite directions and thereby give rise to flow of an electric current that is capable of delivering power to an external circuit. Most solar cells are in the form of a silicon wafer that has been metallized, i.e., provided with metal contacts that are electrically conductive.
Most electric power-generating solar cells currently used on earth are silicon solar cells. Process flow in mass production is generally aimed at achieving maximum simplification and minimizing manufacturing costs. Electrodes in particular are made by using a method such as screen printing from a metal paste.
An example of this method of production is described below in conjunction with FIG. 1.
FIG. 1 shows a p-type silicon substrate, 10.
In FIG. 1(b), an n-type diffusion layer, 20, of the reverse conductivity type is formed by the thermal diffusion of phosphorus (P) or the like. Phosphorus oxychloride (POCl3) is commonly used as the phosphorus diffusion source. In the absence of any particular modification, the diffusion layer, 20, is formed over the entire surface of the silicon substrate, 10. This diffusion layer has a sheet resistivity on the order of several tens of ohms per square (Ω/□), and a thickness of about 0.3 to 0.5 μm.
After protecting the front surface of this diffusion layer with a resist or the like, as shown in FIG. 1(c), the diffusion layer, 20, is removed from the rest of the surfaces by etching so that it remains only on the front surface. The resist is then removed using an organic solvent or the like.
Next, a silicon nitride film, 30, is formed as an anti-reflection coating on the n-type diffusion layer, 20, to a thickness of about 700 to 900 Å in the manner shown in FIG. 1(d) by a process, such as plasma chemical vapor deposition (CVD).
As shown in FIG. 1(e), a silver paste, 500, for the front electrode is screen printed then dried over the silicon nitride film, 30. In addition, a back side silver or silver/aluminum paste, 70, and an aluminum paste, 60, are then screen printed and successively dried on the back side of the substrate. Firing is then typically carried out in an infrared furnace at a temperature range of approximately 700 to 950° C. for a period of from several minutes to several tens of minutes.
Consequently, as shown in FIG. 1(f), aluminum diffuses from the aluminum paste into the silicon substrate, 10, as a dopant during firing, forming a p+ layer, 40, containing a high concentration of aluminum dopant. This layer is generally called the back surface field (BSF) layer, and helps to improve the energy conversion efficiency of the solar cell.
The aluminum paste is transformed by firing from a dried state, 60, to an aluminum back electrode, 61. The back side silver or silver/aluminum paste, 70, is fired at the same time, becoming a silver or silver/aluminum back electrode, 71. During firing, the boundary between the back side aluminum and the back side silver or silver/aluminum assumes an alloy state, and is connected electrically as well. The aluminum electrode accounts for most areas of the back electrode, owing in part to the need to form a p+ layer, 40. Because soldering to an aluminum electrode is impossible, a silver or silver/aluminum back electrode is formed over portions of the back side (often as 5-6 mm wide busbars) as an electrode for interconnecting solar cells by means of copper ribbon or the like. In addition, the front electrode-forming silver paste, 500, sinters and penetrates through the silicon nitride film, 30, during firing, and is thereby able to electrically contact the n-type layer, 20. This type of process is generally called "firing through." This fired through state is apparent in layer 501 of FIG. 1(f).
As noted above, the back surface electrode that is used to interconnect the solar cells through soldering may comprise Ag or Ag/Al compositions. When prior art Ag compositions are used, they can provide good solderability and adhesion. However, since the Ag compositions cannot produce a back surface field, conversion efficiency of the solar cell suffers. On the other hand, when Ag/Al compositions are used, adhesion strength is generally lowered and gives rise to concerns regarding long term reliability. This is due to the fact that the addition of Al will generally hurt solderability and thus, adhesion performance.
Furthermore, there is an on-going effort to provide compositions which are Pb-free while at the same time maintaining electrical performance and other relevant properties of the device. The present inventors provide novel Ag/Al comprising composition(s) and semiconductor devices which simultaneously provide such a Pb-free system while still maintaining electrical performance, and improving adhesion. The current invention provides such compositions and devices. Furthermore, the composition(s) of the present invention lead to reduced bowing in some embodiments of the invention.

Electroconductive thick film composition(s), electrode(s), and semiconductor device(s) formed therefrom


The present trash receptacle (and method for using the same) reduces the suction/vacuum effect in the bottom portion of the receptacle as trash bags or polyliners are removed therefrom. The receptacle includes a vent enabling fluid communication from a first chamber section (at the bottom of the receptacle) to a second chamber section which rests above the first chamber section.

Receptacles or containers for refuse have a variety of useful applications and are available in a number of different sizes. For example, large receptacles (e.g., 44 or 55 gallon receptacles) are commonly used for disposal of trash, grass, leaves, and other materials. Liners are often used in combination with the receptacles to simplify emptying of the receptacles and disposal/transportation of the filled liner.
Many liners are composed of an elastic or deformable material (e.g., polyliner or trash bags) that will conform to the shape of the receptacle. This can cause the liner to conform to the sides of the receptacle during removal, thereby forming a seal and preventing air from passing through to the bottom portion of the receptacle. This seal can create a vacuum or suction effect in the bottom portion of the receptacle as the liner is removed. Thus, as an example, when removing a liner containing dense materials from a larger receptacle, the vacuum may add significantly to the strain suffered by the user.
It is desirable to ventilate the bottom portion of the receptacle so that air can flow into the bottom portion during removal of the liner and prevent or release a vacuum. There is a need to provide an economical way of reducing or minimizing the force required to fully remove the liner from the receptacle without sacrificing the utility or structural integrity of the receptacle.