An analog or digital clock having a ferromagnetic pendulum that is magnetically levitated under feeedback-control and that, alternatively, may be (1) driven at a forced oscillation frequency which is decoupled from and asynchronous with the clock's time control element (e.g., a quartz crystal), (2) driven at a forced oscillation frequency which is coupled to and synchronous with the clock's time control element or (3) oscillated at the resonant frequency of the levitated pendulum and this resonant frequency is used as a time control for determining the clock's timing. Such a levitated pendulum clock is useful for both ornamental and educational purposes.

1. Field of the Invention
This invention relates to clocks employing pendulums and, more particularly, to a clock employing a physically detached pendulum which is magnetically levitated by means of feedback control.
2. Description of the Prior Art
Clocks which employ an oscillating pendulum physically attached to the clock mechanism, wherein the pendulum operates as the time-control element, are notoriously old. More recently, pendulum clocks have been developed wherein the time-control element comprises a quartz crystal and a physically attached oscillating pendulum is employed solely for ornamental purposes.
The art also includes mechanisms for magnetically levitating a ferromagnetic object (which may or may not be permanently magnetized), as well as controlling the spatial position of such a magnetically levitated object.
Further, the art includes a magnetically-levitated pendulum bob, disclosed in U.S. Pat. No. 2,566,221 of W. V. Lovell. Lovell describes an aluminum/copper ball which is levitated by means of magnetic induction. This ball exhibits translatory motion, which would permit the bob to be used as a pendulum. However, magnetic induction based on eddy currents and magnetic repulsion is electrically inefficient. The currents reported by Lovell are simply too high for use in making a practical clock pendulum which is safe for home use.
In addition, the art includes a pendulum clock in which the pendulum is a float disposed in a liquid, disclosed in U.S. Pat. No. 5,159,583 of Lee. This float is oscillated by means of an electromagnet.

Clock having magnetically-levitated pendulum


An apparatus comprising a processor and a transceiver. The processor may (i) receive messages from a plurality of vehicles and (ii) determine relative coordinates of the vehicles based on the messages. The transceiver may (i) communicate the messages using a first channel in a first range and (ii) communicate short messages using a second channel in a second range. Communicating using the second channel may consume more power than communicating using the first channel. The messages may be sent from the transceiver to a cluster head within the first range. The short messages may communicate less data than the messages. The short messages may be sent directly to a target vehicle outside of the first range to determine an associated cluster head for the target vehicle. The messages may be sent to the target vehicle from the associated cluster head via the cluster head within the first range.

Positioning of objects (i.e., vehicles, buildings, pedestrians, etc.) can be determined using GPS (Global Positioning System) or GNSS (Global Navigation Satellite System). Some applications that use positioning, such as assisted driving, need high precision data to be implemented safely. To calculate high precision data with GPS/GNSS, real-time kinematics (RTK) with base-stations are used, which is currently not viable for commercial use. Host vehicle gyros can also be used to estimate a future expected trajectory of objects, but if the initial GPS/GNSS position is incorrect the problem cannot be solved correctly.
In assisted driving applications, such as active intervention, knowledge of the positions of surrounding vehicles with high accuracy is utilized, which is currently implemented using many different sensors covering 360 degrees around a vehicle. There are many vehicle environment detection systems, such as camera systems, Doppler radar systems and LIDAR systems. Inaccuracies can lead to both false-positives and false-negatives. GPS/GNSS does not provide a sufficient degree of accuracy, especially in urban conditions.
Using periodic broadcasts to perform inter-vehicle range estimation can be used to obtain a high degree of accuracy regarding relative positioning between objects. Determining highly accurate relative positioning between objects introduces additional issues. One such issue is that communication is limited by an amount of transmit power. In clustering, the intended communication recipient vehicles are selected based on current traffic scenarios. In some traffic scenarios, parts of the desired clustering group are outside of the communication range of the host vehicle. Conventional vehicle-to-vehicle (i.e., V2V) communication solutions change the group size and members when entering the communication range. In high traffic scenarios, changing the group size and members limits the usefulness of communications.
It would be desirable to implement V2V clustering and multi-hop communication.


A ceramic resonance type electrostatic sensor apparatus with an oscillator at a fixed frequency including a first ceramic resonator which has a fixed resonance frequency, a detecting unit for detecting a capacitance between the detecting unit and an object to be detected, a resonating circuit including a second ceramic resonator and having a resonance point which varies with the small change in capacitance detected by the detecting unit, a high impedance circuit connected between the oscillator and the resonating circuit, and a high impedance circuit connected between the resonating circuit and the detecting circuit.

1. Field of the Invention
The present invention relates to a ceramic resonance type electrostatic sensor apparatus for detecting a change in small capacitance of an object to be detected by using a high-frequency oscillation signal.
2. Description of the Prior Art
A generally used electrostatic sensor apparatus is designed to change the oscillation frequency of an oscillator by changing a capacitance, as an external capacitance, used in a tank circuit of the oscillator. However, the sensitivity of this sensor apparatus is low. For this reason, an apparatus having a higher sensitivity (designed to obtain an AM-modulated wave by changing the capacitance of a capacitor of a resonator having a resonance frequency slightly deviated from the oscillator frequency of an oscillator) has been used more often recently. An electrostatic sensor apparatus comprises an oscillator 1, a resonator 2, a detecting portion 3 for detecting a change in capacitance between the detecting portion and an object to be detected, a detector 4, and an amplifier 5, as shown in FIG. 1. The oscillator 1 and the resonator 2 respectively include resonator elements. The resonance frequency of the resonator element of the resonator 2 is modulated in accordance with a small change in capacitance detected by the detecting portion 3. The modulated resonance frequency is then extracted as an output signal from the resonator 2 and is detected and amplified.
In a widely used electrostatic sensor apparatus of this type, one of the resonator elements of the oscillator and the resonator 2 is constituted by a strip line. However, when a resonator element is to be constituted by a strip line, a strip line length must be 1/4 the wavelength of light. Since a long strip line is required, it is difficult to reduce the apparatus in size.
In order to reduce the size of the apparatus, Japanese Patent Laid-Open No. 58-85948 discloses an apparatus wherein the resonator elements of the oscillator 1 and the resonator 2 are constituted by dielectric resonator elements. If the resonator elements are constituted by dielectric elements, the length of each resonator element can be reduced to .epsilon..sup.-1/2 that of the resonator element constituted by a strip line. If this dielectric element is constituted by a ceramic element, since ceramics have dielectric constants .epsilon. of 20 to 40, the apparatus can be greatly reduced in size. In addition, if each dielectric element is constituted by a ceramic element, since the Q values of ceramics are as high as 200 to 300, the resonator element can be expected to have a higher sensitivity than the resonator element constituted by a strip line.
In an electrostatic sensor apparatus of this type, however, since the operating point of the resonator element of the resonator 2 is set at a point deviated from the resonance frequency of the resonator element of the oscillator 1, an impedance at this operating point is normally 200 to 500 .OMEGA. or more. If a load having an impedance lower than this impedance is coupled to a peripheral portion of the resonator element of the resonator 2, the resonator element is subjected to Q damping (the Q is decreased). That is, the ceramic resonator element cannot exhibit its original characteristics (that the Q is large), and hence the detection sensitivity cannot be greatly increased.
Furthermore, in the electrostatic sensor apparatus shown in FIG. 1, assume that the impedance or Q of an object to be detected is low, and ion components in, e.g., a human body or water are to be detected. In this case, if an object detecting electrode of the detecting portion 3 and the resonator are directly coupled to each other, the Q of the resonator element of the resonator 2 is considerably decreased due to the low impedance of the object. Therefore, in an electrostatic sensor apparatus whose output voltage depends on the large Q of such a resonator element, the detection performance is decreased due to a great decrease in detection output, and the apparatus cannot be used in practice.
In the electrostatic sensor apparatus shown in FIG. 1, if dielectric resonator elements, especially ceramic resonator elements, are used in place of the respective resonator elements of the oscillator 1 and the resonator 2, the apparatus can be reduced in size. In addition, the sensitivity of the apparatus can be greatly increased because of the high Q values (200 to 300) of ceramics. Therefore, the apparatus can detect a small capacitance of about 1.times.10.sup.-5 pF.
FIG. 2 shows the oscillator 1 as a characteristic feature of the electrostatic sensor apparatus in FIG. 1. In this apparatus, a trimmer capacitor 13 for finely adjusting the oscillation frequency is connected to a ceramic resonator element 11 constituting the oscillator 1.
In such a high-sensitivity electrostatic sensor apparatus, the tuning point of the oscillator 1 and the resonator 2 must be accurately set. The capacitance of the trimmer capacitor 13 is known to include a fixed capacitance component C.sub.0 and a variable capacitance component .DELTA.C. The fixed capacitance component C.sub.0 is considerably large and greatly varies in each product. Since the fixed capacitance component C.sub.0 also serves as an oscillator element as indicated by dotted lines in FIG. 2, when a very high oscillation frequency of 1 GHz to 10 GHz is to be used, the oscillation frequency of the oscillator 1 greatly fluctuates due to this variation in C.sub.0. Even if the variation in resonance frequency of the ceramic resonator element 11 is suppressed to the rated value or less, a predetermined oscillation frequency as a target frequency cannot be obtained. Therefore, even if the capacitance is adjusted by the variable capacitance component .DELTA.C, the oscillator 1 and the resonator 2 cannot be set at a predetermined resonance point.
Assume that the resonance point can be accurately set. Even in this case, if a stray distributed capacitance is produced between the electrostatic sensor apparatus and peripheral members when the apparatus is mounted on a unit to be measured, the oscillation frequency is disturbed.
Although the trimmer capacitor 13 is ideally mounted near the ceramic resonator element 11, the capacitor 13 is often required to be mounted at a position separated from the ceramic resonator element 11 due to limitations in terms of a user's requirement, a position of a unit to be measured at which the electrostatic sensor apparatus is mounted and the like. In such a case, the leads of the trimmer capacitor 13 are elongated, and portions L.sub.1 and L.sub.2 of the leads may become capacitance components or inductance components. These components may cause variation in oscillation frequency or parasitic vibrations, resulting in an unstable oscillation frequency.
Recently, a demand has arisen for parallel processing of detection signals based on capacitances detected by an electrostatic sensor apparatus in different forms, or more accurate analysis of detection signals. In order to achieve parallel processing of detection signals, a plurality of sensor circuit systems each constituted by the components from the oscillator 1 to the amplifier 5 may be adjacently arranged. In order to realize accurate signal analysis, at least two sensor circuit systems each constituted by the components from the oscillator 1 to the amplifier 5 may be formed, and a differential output of output signals of the respective systems may be obtained.
In the case wherein the plurality of censor circuits each constituted by the components from the oscillator 1 to the amplifier 5 are arranged adjacent to each other, if a small capacitance is to be detected especially at a high sensitivity of about 1.times.10.sup.-5 pF, it is difficult to match the oscillation frequencies of the respective systems because of the influences of external disturbances other than detection signals or a stray distributed capacitance produced when the electrostatic sensor apparatus is mounted in a unit to be measured. If the oscillation frequencies of the respective systems are deviated from each other even by a slight value, mutual interference such as resonance occurs between the oscillation frequencies of the respective systems. For example, if one the other has an oscillation frequency of f.sub.0 ', a beat frequency of f.sub.0 '-f.sub.0 or f.sub.0 '+f.sub.0 is generated due to mutual interference. This frequency acts as an external disturbance, and accurate signal processing cannot be performed.

Ceramic resonance type electrostatic sensor apparatus


An output buffer circuit comprises a pair of first and second output MOS transistors coupled between a power supply line and a ground line; a booster circuit for boosting the power supply voltage up to a predetermined high voltage higher than a power supply voltage; a complementary MOS circuit comprising a pair of n-channel and p-channel MOS transistors connected in series between an output side of the booster circuit and the ground line; and a level shifter circuit having a first terminal coupled to an output side of a first logic gate for receiving logic signals from the first logic gate, a second terminal coupled to the gates of the n-channel and p-channel MOS transistors of the complementary MOS circuit and a third terminal coupled to the output side of the booster circuit for receiving the predetermined high voltage from the booster circuit, the level shifter circuit performing to shift the logic signal of the logic gate up to at least almost the same level as the predetermined high voltage to supply a shifted up signal to the gates of the n-channel and p-channel MOS transistors of the complementary MOS circuit.

1. Field of the Invention
The present invention provides an output buffer circuit in a semiconductor integrated circuit.
2. Description of the Related Art
In recent years, there has appeared a reduction to 3.3 V of a low power voltage used for driving semiconductor memory devices with a capacity in the range from 4 Mbits to 16 Mbits. Such reduction of the power voltage level renders it difficult to obtain the necessary output voltage of 2.4 V. In the prior art, in order to obtain the necessary output voltage, there is carried out a boost up of a voltage level of the gate of the MOS transistor which performs a switching operation for supplying a high level voltage to the output terminal of the output buffer circuit so that the high level corresponds to the power supply voltage. Conventional boost up circuits for boosting up the output voltage have utilized a capacitor or capacitors which are charged for the boost up only when the logic gate outputs a logic signal as an instruction of the output of the high voltage level from the output terminal of the output buffer circuit. Since the capacitor for the boost up operation begins to charge just before the logic signal is shifted between the high and low levels, there is a considerable necessary time for the charge up of the capacitor for obtaining the boost up of the output voltage which appears on the output terminal, thereby rendering it difficult to allow the output buffer circuit to show a high speed output performance for outputting a sufficiently high output voltage.
A conventional circuit configuration of the output buffer circuit will hereinafter be described with reference to FIG. 1. The conventional output buffer circuit is provided between logic gates and an output terminal 414 and biased by a power supply line which supplies a power supply voltage Vcc and a ground line which supplies a ground voltage. An output stage of the logic circuit comprises first and second NAND gates 401 and 402. An output stage of the output buffer circuit has first and second output n-channel MOS transistors 412 and 415, wherein the first output n-channel MOS transistor 412 is provided in series between the power supply line and the output terminal 414 of the output buffer circuit. The second output n-channel MOS transistor 415 is provided between the ground line and the output terminal 414 of the output buffer circuit. The first output n-channel MOS transistor 412 shows a switching operation associated with digital signals supplied by the first NAND gate 401. The second output n-channel MOS transistor 415 shows a switching operation associated with digital signals supplied by the second NAND gate 402. The first NAND gate 401 has two input terminals, one of which is provided for receipt of a digital signal "OUTH" and another is for receipt of an output enable signal "OE".
The second NAND gate 402 has two input terminals, one of which is provided for receipt of a digital signal "OUTL" and another is for receipt of an output enable signal "OE". The second NAND gate 402 has an output terminal coupled to an input terminal of an inverter 413 which has an output terminal coupled to a gate of the second output n-channel MOS transistor 415. The second output n-channel MOS transistor 415 has a drain coupled to the output terminal 414 of the output buffer circuit and a source coupled to the ground line. Logic signals from the output terminal of the second NAND gate 402 are inverted by the inverter 413 and then inputted into the gate of the second output n-channel MOS transistor 415.
The first NAND gate 401 has an output terminal coupled to gates of p-channel and n-channel MOS transistors 403 and 404 and further coupled to an input terminal of an inverter 405. The p-channel and n-channel MOS transistors 403 and 404 are provided to form the complementary MOS circuit. The p-channel MOS transistor 403 is coupled to the ground line and the n-channel MOS transistor is coupled to the power supply line. An output terminal of the complementary MOS circuit is coupled via an n-channel MOS transistor 407 to the gate of the first output n-channel MOS transistor 412. The output terminal of the first NAND gate 401 is coupled via an inverter 405 to a delay circuit 406. A NAND gate 409 has two input terminals, one of which is coupled to an output terminal of the delay circuit 406 and another input terminal is coupled to the input side of the delay circuit 406. An output terminal of the NAND gate 409 is coupled via an n-channel MOS transistor 408 to a gate of the n-channel MOS transistor 407. A gate of the n-channel MOS transistor 408 is coupled to the power supply line. The output terminal of the NAND gate 409 is coupled to an input terminal of the inverter 410 which has an output terminal coupled via a capacitor 411 to the gate of the first output n-channel MOS transistor 412.
When the NAND gate 401 outputs a high level signal, the p-channel MOS transistor 403 turns OFF and the n-channel MOS transistor 404 turns ON thereby the ground voltage is supplied via the n-channel MOS transistor 404 to the n-channel MOS transistor 407. The low level signal is also supplied to the inverter 405 and inverted by the inverter 405 into the high level signal. The high level signal is supplied to the delay circuit 406 which supplies the high level signal with a time delay. The high level signal with the time delay is then supplied to the input terminal of the NAND gate 409. The high level signal without any time delay is also supplied with the NAND gate 409. For an initial time duration, the NAND gate 409 outputs the high level signal and subsequently outputs the low level signal. For the initial time duration, the high level signal is inputted into the inverter 410 and then inverted into the low level signal which is further applied onto the capacitor 411. However, for the subsequent time duration, the NAND gate 409 outputs the low level signal which is supplied via the n-channel MOS transistor 408 into the gate of the n-channel MOS transistor 407 thereby the n-channel MOS transistor 407 turns OFF. On the other hand, the low level signal is supplied to the inverter 410 and then inverted into the high level signal which is further applied with the capacitor 411. As a result, the capacitor 411 is charged up where the n-channel MOS transistor is in the OFF state. The gate of the first output n-channel MOS transistor 412 is charged up with a considerable time delay and then turns ON thereby the power supply voltage appears with the considerable time delay. This means that the output buffer circuit which utilizes a capacitor for boosting up the high voltage level is engaged with the issue of a response time delay.
Another conventional output buffer circuit is disclosed and illustrated in FIG. 2. This conventional output buffer circuit is provided between the logic gates, for example, first and second NAND gates 501 and 502 and an output terminal 516. First and second output n-channel MOS transistors 515 and 517 are provided between a power supply line and a ground line. The first n-channel MOS transistor 515 is coupled between the power supply line Vcc and the output terminal 516. The second n-channel MOS transistor 517 is coupled between the ground line and the output terminal 516. The gate of the second output n-channel MOS transistor 517 is coupled via an inverter 514 to the second NAND gate 502. The gate of the first output n-channel MOS transistor 515 is coupled via a complementary MOS circuit to the first NAND gate 501 wherein the complementary MOS circuit comprises p-channel and n-channel MOS transistors 512 and 513. The n-channel MOS transistor 513 is coupled to the ground line and the p-channel MOS transistor 512 is coupled via an n-channel MOS transistor 508 to the power supply line. The n-channel MOS transistor 512 is also coupled via a capacitor 511 to an output side of a complementary MOS circuit comprising p-channel and n-channel MOS transistors 509 and 510. An input terminal of the complementary MOS circuit is coupled to the output terminal of the first NAND gate 501 and coupled via a capacitor 505 and n-channel MOS transistors 503 and 504 to the power supply line Vcc. The n-channel MOS transistors have diode connections wherein gates thereof are coupled to drain sides thereof respectively. The drain of the n-channel MOS transistor 504 is coupled to a gate of the n-channel MOS transistor 508. An n-channel MOS transistor 507 is coupled between the power supply line and the gate of the n-channel MOS transistor 508. A gate of the n-channel MOS transistor 507 is coupled to the drain of the n-channel MOS transistor 508. An n-channel MOS transistor 506 is coupled between the power supply line and the gate of the n-channel MOS transistor 508. A gate of the n-channel MOS transistor 506 is coupled to the power supply line Vcc.
The above two conventional output buffer circuits have the following disadvantages. The boosting up operation of the gate of the output MOS transistor is commenced after the charge up operation of the gate thereof up to the power supply voltage. The boosting up operation is thus completed with a large time delay. If the timing of the commencement of the boosting up operation is set earlier than the necessary time, this results in an insufficient voltage level boosted up thereby the output n-channel MOS transistor provides a certain voltage drop from the power supply voltage. Therefore, the above two conventional output buffer circuits are unable to satisfy both the requirements for the high speed response and the sufficiently high driving voltage level applied to the gate of the output MOS transistor coupled between the power supply line and the output terminal of the output buffer circuit. For that reason, it had been required to develop a quite novel output buffer circuits which is capable of satisfying the above both requirements for the high speed response and the sufficiently high driving voltage level applied to the gate of the output MOS transistor coupled between the power supply line and the output terminal of the output buffer circuit.


Disclosed is a quantum-dot LED and fabrication method thereof. The quantum-dot LED includes: a substrate; a n-type semiconductor layer formed on the substrate; an insulator layer formed on the n-type semiconductor layer and provided with a plurality of holes; quantum dots formed by filling the holes; and a p-type semiconductor layer formed on the insulator layer in which the quantum dots are formed. According to the inventive LED, the size and density of the quantum dots are controllable to thereby make the property control of the LED easy. Also, since it can be anticipated that the LED has a high internal quantum efficiency compared with the conventional LED using quantum well, high light emitting efficiency can be obtained.

FIG. 1 illustrates a light emitting diode (hereinafter referred to as 'LED') in which quantum well layer is formed as the light emitting layer.
Referring to FIG. 1, the LED includes a substrate 1, and a n-type semiconductor layer 2, a quantum well layer 3 and a p-type semiconductor layer 4, which are laminated in the named order on the substrate 1.
In the LED of FIG. 1, when a forward bias is applied to the LED, electrons are supplied from the n-type semiconductor layer 2 and holes are supplied from the p-type semiconductor layer so that electrons and holes are recombined with each other in the quantum well layer 3. In the course of recombination, the LED emits light with an energy corresponding to excited level of quantum well or energy bandgap difference.
At this time, the quantum well layer 3 serves as the light emitting layer and accordingly shows a high internal quantum efficiency compared with an LED having a double heterojunction structure, but it is the reality that the internal quantum efficiency does not exceed 10%.
To this end, even when the LED is used as a high power LED, it has a drawback in that power consumption is high, a lot of heat is generated and the generated high temperature heat changes the characteristic of the LED to thereby lower the reliability.


In a self-oscillating mixing stage for FM radio receivers, comprising a transistor producing the oscillator signal and to whose emitter circuit the high-frequency signal is coupled and from whose collector circuit the intermediate-frequency signal is coupled out, the transistor being operated in the grounded-collector circuit mode to produce the oscillator signal and in the grounded-base circuit mode to process the high-frequency and intermediate-frequency signals.

The invention relates to a self-oscillating mixing stage for FM radio receivers comprising a transistor, for producing the oscillator signal and in whose base-emitter circuit the high-frequency signal is coupled in and from whose collector circuit the intermediate-frequency signal is coupled out, an absorption circuit for the intermediate-frequency signal, this absorption circuit being formed by an inductance and a capacitance, being provided in the emitter circuit of this transistor. Known self-oscillating mixing stages of this type are usually operated in the grounded-base circuit mode to produce the oscillator signal and also to process the high-frequency and the intermediate-frequency signal, respectively. An important requirement such self-oscillating mixing stages must satisfy is for the intermediate-frequency circuit to be properly isolated from the oscillator circuit to ensure that this stage performs, in general, its function as an oscillator as an well as intermediate-frequency stage, in a perfect manner over the overall receiving range and that no instabilities are produced.

Self-oscillating converter for ultrashort wave radio receivers


The present invention provides a production process for a terminal-end-stabilized glyoxylic acid (salt)-based polymer, which process enables to reduce the amount of the polymerization solvent, as recovered or removed after the end of the polymerization (before the start of the hydrolysis) or after the end of the hydrolysis, without lowering the production efficiency. The production process for a terminal-end-stabilized glyoxylic acid (salt)-based polymer comprises the step of polymerizing a monomer component including a glyoxylic acid ester in order to produce the terminal-end-stabilized glyoxylic acid (salt)-based polymer, wherein a terminal end stabilizer is used as a reaction medium of the polymerization.

A. Technical Field
The present invention relates to a production process for a glyoxylic acid (salt)-based polymer. More specifically, the present invention relates to a production process for a terminal-end-stabilized glyoxylic acid (salt)-based polymer.
B. Background Art
A glyoxylic acid (salt)-based polymer has many carboxyl groups in its molecule and therefore displays an excellent function of binding (chelating) the calcium ion or magnesium ion present in water and then dispersing clay and dirt, and further, the glyoxylic acid (salt)-based polymer contains no phosphorus causing environmental pollution such as eutrophication of rivers etc. and is therefore hitherto favorably used as a detergent builder.
As to production processes for the glyoxylic acid (salt)-based polymer, for example, JP-A-052196/1979 and JP-A-050316/1987 (corresponding to U.S. Pat. No. 4,600,750) disclose: a process which comprises the step of polymerizing a glyoxylic acid ester by using a solvent such as an alkanenitrile, a halogenated hydrocarbon, dimethyl sulfoxide, or acetone in order to obtain a glyoxylic acid-based polymer; and a process which comprises the step of further saponifying (hydrolyzing) the glyoxylic acid-based polymer in order to obtain a glyoxylic acid salt-based polymer.
In addition, the glyoxylic acid (salt)-based polymer has unstable terminal end portions because the main chain of this polymer has an acetal structure. Accordingly, in the case where, in order to isolate the glyoxylic acid (salt)-based polymer, a reaction liquid containing the polymer is for example heated to remove a solvent etc. therefrom, the main chain is cut off from the terminal end portions of the polymer, so that the polymer decomposes (depolymerizes). In other words, it is difficult to isolate or purify the glyoxylic acid (salt)-based polymer stably in a high yield. Therefore, a process is disclosed which process comprises the step of stabilizing the terminal end portions of the glyoxylic acid (salt)-based polymer by treating it with a terminal end stabilizer. For example, U.S. Pat. No. 4,144,226, U.S. Pat. No. 4,204,052, U.S. Pat. No. 4,225,685, and U.S. Pat. No. 4,226,960 disclose a process which comprises the step of polymerizing a glyoxylic acid ester by using a solvent such as an alkanenitrile, a halogenated hydrocarbon, dimethyl sulfoxide, or acetone, in which process a terminal end stabilizer is added during or after the polymerization.
However, the above conventional production processes have problems in respect to production efficiency and cost because the polymerization solvent must be recovered or removed after the end of the polymerization (before the start of the hydrolysis) or after the end of the hydrolysis. In addition, in the case where the amount of the polymerization solvent as used is decreased in order to reduce the recovery or removal amount of the polymerization solvent, there are problems in that the viscosity of the polymerization liquid rises to deteriorate the agitation efficiency. Furthermore, an organic solvent such as an alkanenitrile, a halogenated hydrocarbon, dimethyl sulfoxide, or acetone is hitherto used as the polymerization solvent, therefore there might occur problems in respect to safety and environmental pollution resistance if a part of the above solvent remains after the step of recovering or removing it.
A. Object of the Invention
An object of the present invention is to provide a production process for a terminal-end-stabilized glyoxylic acid (salt)-based polymer, which process enables to reduce the amount of the polymerization solvent, as recovered or removed after the end of the polymerization (before the start of the hydrolysis) or after the end of the hydrolysis, without lowering the production efficiency.
B. Disclosure of the Invention
The present inventors diligently studied to solve the above problems. As a result, they have hit on ideas that: (1) the terminal end stabilizer, which is conventionally added during or after the polymerization in order to stabilize the terminal ends of the glyoxylic acid (salt)-based polymer, can be utilized as a reaction medium of the polymerization; and (2) if the polymerization reaction of a monomer component including a glyoxylic acid ester and the terminal-end-stabilizing reaction can be run by their respective catalysts having different functions, then the terminal end stabilizer serves as a reaction medium without reacting during the polymerization reaction, and can be made to react by adding a terminal-end-stabilizing catalyst into the system after the polymerization. Then, the inventors have completed the present invention by finding that the above problems can be solved by the above ideas.
That is to say, a production process for a terminal-end-stabilized glyoxylic acid (salt)-based polymer, according to the present invention, comprises the step of polymerizing a monomer component including a glyoxylic acid ester in order to produce the terminal-end-stabilized glyoxylic acid (salt)-based polymer, wherein a terminal end stabilizer is used as a reaction medium of the polymerization. Preferably, if the polymerization of the monomer component including the glyoxylic acid ester is carried out as an anionic polymerization, and if a cationically polymerizable one is used as the terminal end stabilizer, then the terminal end stabilizer serves as a reaction medium without reacting until adding an acid catalyst into the polymerization system, and the addition of the acid catalyst then causes the terminal end stabilizer to react with the terminal ends of the glyoxylic acid (salt)-based polymer (as obtained by the anionic polymerization of the monomer component including the glyoxylic acid ester) in order to stabilize the terminal ends of this polymer.
The adoption of this constitution enables to simplify the polymerization solvent recovery or removal step without lowering the production efficiency and to more easily produce the glyoxylic acid (salt)-based polymer.
These and other objects and the advantages of the present invention will be more fully apparent from the following detailed disclosure.
Hereinafter, the production process for the terminal-end-stabilized glyoxylic acid (salt)-based polymer, according to the present invention, is explained in detail.
Monomer Component Including Glyoxylic Acid Ester
The monomer component including the glyoxylic acid ester, as used in the present invention production process, is explained at first.
The glyoxylic acid ester, as included in the above monomer component, is represented by general formula (1) below:
OHCxe2x80x94COxe2x80x94OR1xe2x80x83xe2x80x83(1)
where R1 represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, or an aromatic hydrocarbon group.
For decreasing the steric hindrance during the polymerization, it is more favorable that the above glyoxylic acid ester has an alkyl group having 1 to 4 carbon atom as the substituent which is represented by R1 in the above formula. Specific examples of the glyoxylic acid ester include methyl glyoxylate, ethyl glyoxylate, n-propyl glyoxylate, iso-propyl glyoxylate, n-butyl glyoxylate, isobutyl glyoxylate, sec-butyl glyoxylate, and t-butyl glyoxylate. These glyoxylic acid esters can be used either alone respectively or in combinations with each other. Of the above glyoxylic acid esters, methyl glyoxylate and ethyl glyoxylate are more favorable, and methyl glyoxylate is still more favorable.
The production process for the glyoxylic acid ester is not especially limited. The glyoxylic acid ester can easily be produced, for example, by dehydration of a hemiacetal ester of glyoxylic acid by use of phosphorus pentoxide or sulfuric acid, wherein the hemiacetal ester is obtained by a reaction of glyoxylic acid hydrate and an alcohol.
Incidentally, the glyoxylic acid ester might gradually polymerize even during its storage (preservation) according to storage conditions. Therefore, it is desirable to purify the glyoxylic acid ester by a procedure such as distillation to remove impurities such as polymerized products before use. In other words, it is desirable that the glyoxylic acid ester to be used for the polymerization is as pure as possible. In addition, it is desirable to polymerize the glyoxylic acid ester immediately after its purification.
If necessary, the monomer component may further comprise a monomer (comonomer) which is other than the glyoxylic acid ester and copolymerizable with the glyoxylic acid ester. An anionically copolymerizable comonomer is preferable for controlling the polymerization and the molecular weight. Specific examples thereof include aldehydes having 1 to 20 carbon atoms, such as formaldehyde and acetaldehyde, but are not especially limited. These monomers can be used either alone respectively or in combinations with each other according to demand. Of the above-exemplified monomers, compounds having 1 to 4 carbon atoms are more favorable. It is desirable that the above monomer is as pure as possible, and it is particularly preferable that the contents of acid components and active-hydrogen-containing compounds in the above monomer are low. Therefore, the xe2x80x9cglyoxylic acid-based polymerxe2x80x9d in the present invention means a homopolymer or copolymer of the glyoxylic acid ester.
When the monomer component further comprises the above other monomer, the content of this monomer is not especially limited, but is favorably in the range of 5 to 0 mol, more favorably 3 to 0 mol, still more favorably 1 to 0 mol, particularly favorably 0.5 to 0 mol, per 1 mol of the glyoxylic acid ester. In the case where the content of the above other monomer exceeds 5 mols, it might be impossible to obtain the glyoxylic acid salt-based polymer which is favorably utilized for the above various uses. In addition, the glyoxylic acid-based polymer, according to the present invention, is particularly preferably a homopolymer of the glyoxylic acid ester.
Terminal End Stabilizer
There is no limitation in respect to the terminal end stabilizer, as used in the production process according to the present invention, if the terminal end stabilizer does not display reactivity during the polymerization of the monomer component including the glyoxylic acid ester. However, a cationically polymerizable one is preferable. Specific examples thereof include: alkyl vinyl ethers, such as ethyl vinyl ether, propyl vinyl ether, and butyl vinyl ether; and epoxides, such as ethylene oxide, propylene oxide, and epichlorohydrin, but are not especially limited. Of these, propylene oxide and ethyl vinyl ether are preferable for displaying the effects of the present invention enough. These terminal end stabilizers can be used either alone respectively or in combinations with each other.
The terminal end stabilizer reacts with the unstabilized (in other words, easily depolymerizable) terminal ends to thereby stabilize them. In one of specific examples, the unstabilized terminal ends of the glyoxylic acid-based polymer are hydroxyl groups (xe2x80x94OH) or alcoholates (xe2x80x94Oxe2x80x94), therefore the terminal end stabilizer reacts with these functional groups to thereby prevent the hydrolysis of the glyoxylic acid-based polymer from easily occurring.
Polymerization Reaction
In the production process according to the present invention, the polymerization of the above monomer component including the glyoxylic acid ester is carried out. One of characteristics of the present invention is to use the above terminal end stabilizer as a reaction medium of this polymerization.
The amount of the terminal end stabilizer, used as a polymerization reaction medium in the present invention, may be set according to such as kind thereof or molecular weight of the glyoxylic acid-based polymer, and is not especially limited. However, the amount of the terminal end stabilizer is preferably in the range of 1.1 to 50 in molar ratio to the terminal end portions of the glyoxylic acid-based polymer. In the case where the molar ratio of the terminal-end-stabilizing compound is lower than 1.1, it might be impossible to stabilize the glyoxylic acid-based polymer enough. In addition, in the case where the molar ratio exceeds 50, side reactions other than the addition reaction easily occur because much of the terminal-end-stabilizing compound remains unreacted. In the case where the terminal end stabilizer is an alkylene oxide, there are no especial problems if the glyoxylic acid-based polymer is saponified even though much of the alkylene oxide remains unreacted, because the unreacted alkylene oxide is converted into an alkylene glycol by the saponification.
As is shown above, in the present invention production process for the terminal-end-stabilized glyoxylic acid (salt)-based polymer, the terminal end stabilizer is used as a reaction medium of the polymerization of the monomer component including the glyoxylic acid ester. However, a small amount of organic solvent may be used as a reaction medium together with the terminal end stabilizer. The amount of the organic solvent, which is if necessary included in the reaction medium as used for the polymerization, is favorably in the range of 0 to 20 weight %, more favorably 0 to 10 weight %, still more favorably 0 to 5 weight %. In addition, a mode in which the organic solvent is not used together is particularly preferable for safety and environmental pollution resistance because the organic solvent does not remain. In the case where the ratio of the organic solvent in the reaction medium exceeds 20 weight %, there are disadvantages in that the effects of the present invention cannot be displayed enough.
In addition, in the present invention production process for the terminal-end-stabilized glyoxylic acid (salt)-based polymer, the polymerization concentration of the monomer component including the glyoxylic acid ester is favorably in the range of 20 to 99 weight %, more favorably 40 to 98 weight %, still more favorably 50 to 95 weight %.
Examples of the organic solvent, usable together with the terminal end stabilizer, include: aromatic hydrocarbons, such as benzene, toluene, and xylene; aliphatic hydrocarbons, such as cyclohexane and n-hexane; halogenated hydrocarbons, such as methylene chloride; carboxylic acid esters, such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and methyl propionate; ketone compounds, such as acetone; ether compounds, such as tetrahydrofuran and dioxane; alkanenitriles, such as acetonitrile and propionitrile; and dimethyl sulfoxide. Of them, the carboxylic acid esters are particularly favorable.
Incidentally, the above organic solvents are usable together with the terminal end stabilizer, but some organic solvents make it difficult to obtain a glyoxylic acid (salt)-based polymer having a desirable molecular weight when used together with the terminal end stabilizer. Examples of such organic solvents include: alcohols, such as methanol and ethanol; primary amines and secondary amines; carboxylic acids, such as acetic acid; phenols, such as phenol and cresol; and other compounds having an active hydrogen. These can be used as initiators because these serves as initiators of the polymerization. However, in the case where they are used as solvents, it might be difficult to obtain the glyoxylic acid (salt)-based polymer having the desirable molecular weight.
If, as is shown above, the terminal end stabilizer is used as a polymerization reaction medium, even a small amount thereof serves as a reaction medium, and enables to carry out the polymerization while inhibiting the deterioration of the agitation efficiency by suppressing the rise of the viscosity during the polymerization. Therefore, the scale of the solvent recovery or removal process, which is necessary when using a large amount of solvent in conventional production processes for the glyoxylic acid (salt)-based polymer, can be diminished, or the above solvent recovery or removal process becomes unnecessary according to circumstances. Furthermore, when the solvent is conventionally recovered or removed, there is a possibility that the polymer might decompose according to conditions for such as heating treatment in the solvent recovery or removal process. However, the production process according to the present invention can avoid such a possibility. In addition, this production process can be proposed as a production process for a glyoxylic acid (salt)-based polymer which process is very excellent in respect to safety and environmental pollution, because the amount of the organic solvent as conventionally used, such as a halogenated hydrocarbon having high toxicity, can be diminished as much as possible, or because the use of such an organic solvent becomes unnecessary.
In addition, in the present invention production process, more favorably, if the kind of the terminal end stabilizer is selected and if the polymerization reaction of the monomer component including the glyoxylic acid-based monomer and the terminal-end-stabilizing reaction of the produced glyoxylic acid (salt)-based polymer are run by their respective catalysts having different functions, then the terminal end stabilizer serves as a reaction medium without reacting during the polymerization reaction, and can be made to react by adding a terminal-end-stabilizing catalyst into the system after the polymerization. In other words, in the case where the polymerization reaction is carried out by anionic polymerization, a compound which reacts by an acid catalyst is used as the terminal end stabilizer. On the other hand, in the case where the polymerization reaction is carried out by cationic polymerization, a compound which reacts by a basic catalyst is used as the terminal end stabilizer. In a preferable mode, the polymerization reaction is carried out by anionic polymerization, and the terminal end stabilizer is made to react by the acid catalyst.
As to polymerization initiators, anionic-polymerization initiators are preferable for displaying the effects of the present invention enough. Specific examples thereof include: water; alcohols (hydric polymerization initiators), such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and dodecyl alcohol; alkyl glycolates; polyalkylene glycols, polyalkylene glycol monoalkyl ethers; and dialkyl alkyltartronates; but are not especially limited. These polymerization initiators can be used either alone respectively or in combinations with each other. Of the above-exemplified polymerization initiators, methyl alcohol is more favorable. The amount of the polymerization initiator as used may be adjusted according to such as molecular weight of the desired glyoxylic acid-based polymer, and is not especially limited.
Incidentally, the above methyl alcohol, polyalkylene glycols (e.g. polyethylene glycol), etc., which are used as polymerization initiators in the present invention, are distinguished from the terminal end stabilizer as used in the present invention. That is to say, if the polymerization initiators, such as methyl alcohol and polyalkylene glycols, are used, they structurally block one terminal end of the polymer and apparently serve as if they were terminal end stabilizers, but this blocking is made upon only one side terminal end, therefore the above polymerization initiators are different from what stabilizes both terminal ends of the polymer like the terminal end stabilizer as used in the present invention.
As to polymerization catalysts, those which selectively contribute to the polymerization of the glyoxylic acid ester are favorable, and basic ones are suitable. In other words, it is more favorable to anionically polymerize the above monomer component. The basic catalyst is not especially limited, but examples thereof include: alkaline metal hydroxides, such as sodium hydroxide and potassium hydroxide; alkaline metal alkoxides; amines; pyridine; 2-hydroxypyridine-H2O complex; and sodium monomethyl malonate; and of them, particularly, amines, pyridine, and 2-hydroxypyridine.H2O complex are preferable. These basic catalysts can be used either alone respectively or in combinations with each other. The amount of the polymerization catalyst as used may be adjusted according to such as molecular weight of the desired glyoxylic acid-based polymer, and is not especially limited.
Specific examples of usable polymerization methods include: a method which comprises the steps of charging the monomer component into a reactor together with the polymerization initiator, catalyst, or solvent all at once, and then carrying out the polymerization; and a method which comprises the steps of charging the polymerization initiator, catalyst, or solvent into a reactor, and then carrying out the polymerization while successively adding (for example, dropwise adding) the monomer component into the reactor. However, the polymerization method is not especially limited.
The polymerization conditions such as polymerization temperature and polymerization time are not especially limited, but the polymerization temperature is more favorably adjusted in the range of xe2x88x9250 to 50xc2x0 C. because the polymerization is an exothermic reaction. In addition, in the final stage of the polymerization, it is more favorable that the polymerization temperature is adjusted in the range of xe2x88x9230 to 30xc2x0 C. The polymerization time may fitly be adjusted according to such as polymerization temperature. In addition, because the glyoxylic acid ester easily reacts with oxygen or water, it is desirable to carry out the above polymerization in the absence of oxygen or water, in other words, under an inert gas atmosphere such as nitrogen gas. Furthermore, it is desirable that all steps for producing the glyoxylic acid-based polymer are carried out under the inert gas atmosphere. Incidentally, the polymerization may be carried out under normal (atmospheric) pressure, but can also be carried out under reduced or increased pressure.
The above polymerization can give the glyoxylic acid-based polymer in a state of a solution in which the glyoxylic acid-based polymer is dissolved in the solvent. The molecular weight of the glyoxylic acid-based polymer is not especially limited, but may be set according to its uses. For example, when the glyoxylic acid (salt)-based polymer is used as a detergent builder, the degree of polymerization of the glyoxylic acid ester is favorably in the range of 5 to 1,000, more favorably 15 to 300, because the dissolution rate of the polymer in water might not reach a desirable value.
Terminal End Stabilization by Addition of Catalyst
The glyoxylic acid-based polymer, which is obtained by polymerizing the monomer component including the glyoxylic acid-based monomer such as glyoxylic acid ester, has unstable terminal end portions because the main chain of this polymer has an acetal structure. Accordingly, in the case where, in order to isolate the glyoxylic acid-based polymer, a reaction liquid containing the polymer is for example heated to remove a solvent etc. therefrom, the main chain is cut off from the terminal end portions of the polymer, so that the polymer decomposes (depolymerizes). In other words, it is impossible to isolate or purify the glyoxylic acid-based polymer stably in a high yield. Therefore, the isolation of the glyoxylic acid-based polymer needs the stabilization of the terminal end portions of the glyoxylic acid-based polymer.
The method for the terminal end stabilization in the production process according to the present invention is carried out by adding a catalyst, having a function different from that of a catalyst as used for the polymerization reaction, into the reaction system of the aforementioned polymerization reaction. In other words, the essential terminal-end-stabilizing reaction is caused by adding the aforementioned catalyst to the terminal end stabilizer which is used as a reaction medium during the polymerization.
The catalyst as used for the terminal-end-stabilizing reaction is preferably an acid catalyst. Specific examples thereof include: protonic acids, such as halogenated hydrogens (e.g. hydrochloric acid), hydrobromic acid, hydroiodic acid, trifluoroacetic acid, and phosphoric acid; Lewis acids, such as metal halides (e.g. aluminum chloride) and organoaluminum compounds (e.g. alkylaluminum halides, trialkylaluminum); but are not especially limited. These acid catalysts can be used either alone respectively or in combinations with each other. Incidentally, it is also possible that the acid catalyst is used for the reaction in a state of a solution obtained by dissolving it into aliphatic hydrocarbons such as hexane, if necessary.
The amount of the acid catalyst as used relative to the glyoxylic acid-based polymer or terminal-end-stabilizing compound may be set according to such as the kind of the acid catalyst, the combinations with the glyoxylic acid-based polymer or terminal-end-stabilizing compound, or the molecular weight of the glyoxylic acid-based polymer, and is not especially limited. However, the solution of the glyoxylic acid-based polymer contains a basic substance B such as the polymerization catalyst as used for the polymerization. Therefore, it is necessary to use the acid catalyst in an amount larger than that required for neutralizing these basic substances B.
The preferred amount of the above acid catalyst as used is favorably in the range of 1.1 to 200 mols, more favorably 1.5 to 100 mols, still more favorably 2 to 50 mols, per 1 mol of the basic substance present in the reaction system.
The reaction conditions for the reaction of the terminal end stabilizer are not especially limited, but the reaction temperature is favorably in the range of xe2x88x9250 to 50xc2x0 C., more favorably xe2x88x9230 to 40xc2x0 C., particularly favorably xe2x88x9220 to 35xc2x0 C. The reaction time may fitly be adjusted according to such as reaction temperature. In addition, it is desirable to carry out the above reaction in the absence of oxygen or water, in other words, under an inert gas atmosphere such as nitrogen gas. Furthermore, it is desirable that all steps for stabilizing the glyoxylic acid-based polymer are carried out under the inert gas atmosphere. Incidentally, the reaction may be carried out under normal (atmospheric) pressure, but can also be carried out under reduced or increased pressure.
The above addition reaction introduces the terminal end stabilizer into the glyoxylic acid-based polymer as terminal end groups thereof, and thereby stabilizes this polymer.
In the production process according to the present invention, if necessary, acid substances which remain in the system may be deactivated by adding a basic compound A after the terminal-end-stabilizing reaction has been carried out by adding the above acid catalyst.
Examples of the above basic compound A include: alkaline metal hydroxides, such as sodium hydroxide and potassium hydroxide; alkaline metal alkoxides; alkaline metal carbonates; and amines; but are not especially limited. Specific examples of the above amines include: aliphatic amines, such as ethylamine, n-propylamine, isopropylamine, n-butylamine, sec-butylamine, t-butylamine, dodecylamine, octadecylamine, dimethylamine, diethylamine, dipropylamine, triethylamine, N,N-dimethyldodecylamine, cyclohexylamine, and dicyclohexylamine; allylamine; aromatic amines, such as benzylamine and aniline; pyridine; alkanolamines, such as monoethanolamine, diethanolamine, and triethanolamine; but are not especially limited. These basic compounds A can be used either alone respectively or in combinations with each other.
Of the above-exemplified basic compounds A, the amines are more favorable. In addition, more favorable ones of the above-exemplified amines are those which have a boiling point of not lower than 80xc2x0 C., still more favorably not lower than 100xc2x0 C., particularly favorably not lower than 120xc2x0 C. In addition, the alkanolamines are still more favorable. The tertiary amines are particularly favorable because such amines become less colored. Triethanolamine is the most favorable because it is more excellent in safety and is more odorless.
The amount of the basic compound A as used relative to the acid catalyst may be set according to such as kinds or combinations of both, and is not especially limited. However, it is more favorable to add the basic compound A in an amount of 10 to 200 mol %, more favorably 50 to 150 mol %, of the acid catalyst (as added during the reaction) into the reaction system, that is, reaction liquid (addition reaction mixture). Thereby, the acid catalyst as contained in the reaction liquid can be deactivated. Incidentally, the acid catalyst is consumed in some degree during the addition reaction. Therefore, even though an equivalent mol of basic compound A is not added to the initially added acid catalyst, it might be possible to achieve the deactivation of the acid catalyst.
Terminal-End-Stabilized Glyoxylic Acid-Based Polymer
The method for isolating or purifying the stabilized glyoxylic acid-based polymer is not especially limited.
The terminal-end-stabilized glyoxylic acid-based polymer, obtained by the production process according to the present invention, is very excellent in respect to safety and environmental pollution, because the organic solvent, such as halogenated hydrocarbon having high toxicity, substantially does not remain in the polymer. Furthermore, the polymer, obtained by the production process according to the present invention, contains only an extremely small amount of residual solvent, and the case where the solvent substantially does not remain in the polymer is also realizable. Therefore, there are advantages of increasing the purity of the polymer.
Terminal-End-Stabilized Glyoxylic Acid Salt-Based Polymer
In the production process according to the present invention, the glyoxylic acid-based polymer may be saponified (hydrolyzed) in order to convert it into a glyoxylic acid salt-based polymer, if necessary. In other words, the glyoxylic acid-based polymer, as stabilized by the above method, can be saponified (hydrolyzed) by using strongly basic and water-soluble metal hydroxides, specifically, mono-, di-, and trivalent metal hydroxides such as alkaline metal hydroxides and alkaline earth metal hydroxides. The saponification of the glyoxylic acid-based polymer, for example, can afford water solubility to the polymer (convert the polymer into a water-soluble one).
Examples of the above alkaline metal hydroxides include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of the above alkaline earth metal hydroxides include magnesium hydroxide and calcium hydroxide. These metal hydroxides can be used either alone respectively or in combinations with each other. Of the above-exemplified metal hydroxides, sodium hydroxide and potassium hydroxide are more favorable, and sodium hydroxide is particularly favorable, for the case where the glyoxylic acid salt-based polymer is, for example, used as a detergent builder. It is desirable that the amount of the metal hydroxide as used relative to the glyoxylic acid-based polymer is excessive by about 5 to about 50 % of the theoretical amount.
The reaction method for the saponification is not especially limited, but a preferable method comprises the step of carrying out the saponification by all at once or successively (e.g. dropwise) adding an aqueous solution of the metal hydroxide into the glyoxylic acid-based polymer as stabilized by the aforementioned method. In addition, when carrying out the saponification, water may beforehand be added to the glyoxylic acid-based polymer, if necessary. Incidentally, the concentration of the above aqueous solution and the amount of water as added are not especially limited. In addition, the saponification can be carried out also in a state of the reaction liquid (addition reaction mixture) without isolating the glyoxylic acid-based polymer, if necessary.
The reaction conditions for the saponification are not especially limited, but the reaction temperature is more favorably in the range of 35 to 75xc2x0 C., still more favorably 45 to 65xc2x0 C. The reaction time may fitly be adjusted according to such as reaction temperature. Incidentally, the saponification may be carried out under normal (atmospheric) pressure, but can also be carried out under reduced or increased pressure.
A metal salt of the glyoxylic acid-based polymer, namely, the glyoxylic acid salt-based polymer, is obtained in a state of a solution, slurry or gel by the above saponification (hydrolysis). It is desirable to maintain the pH of the reaction liquid at a value of larger than 9.5, more favorably larger than 10.0, after the saponification.
The method for isolating or purifying the glyoxylic acid salt-based polymer, for specific example, may be carried out by heating the reaction liquid containing the polymer in order to remove such as alcohols as side-produced by the saponification, but the method is not especially limited. Thereby, the glyoxylic acid salt-based polymer can be isolated or purified stably in a high yield in a state of a dry solid or wet cake. The glyoxylic acid salt-based polymer can favorably be used, for example, for detergent builders, chelating agents, complexing agents, sequestering agents, and various dispersants. Specific examples thereof are shown below.
In addition, the terminal-end-stabilized glyoxylic acid salt-based polymer, obtained by the production process according to the present invention, is very excellent in respect to safety and environmental pollution, because the organic solvent, such as halogenated hydrocarbon having high toxicity, substantially does not remain in the polymer.
In addition, as to the production process according to the present invention, in the case where the glyoxylic acid-based polymer is not isolated, more specifically, in the case where the solvent is not removed or recovered before carrying out the saponification, it is also possible that both the step of deactivating the acid catalyst by adding the basic compound A into the reaction liquid (addition reaction mixture) and the step of obtaining the glyoxylic acid salt-based polymer by saponifying (hydrolyzing) the glyoxylic acid-based polymer are carried out in one step. In other words, it is also possible that the deactivation of the acid catalyst and the saponification of the glyoxylic acid-based polymer are carried out in one step by using the metal hydroxide as the above basic compound A. The amount of the metal hydroxide (basic compound A), as used in this case, may be set considering the amount of the glyoxylic acid ester as charged for the polymerization and the amount of the acid catalyst as added for the addition reaction.
Uses
As is mentioned above, the terminal-end-stabilized glyoxylic acid (salt)-based polymer, as obtained by the production process according to the present invention, is a polymer in which the organic solvent, such as halogenated hydrocarbon having high toxicity, substantially does not remain, and which is very excellent in respect to safety and countermeasures against environmental pollution. Therefore, this polymer is favorably used particularly for such as detergent builders, detergent compositions, chelating agents, fiber-treating agents, chemicals for paper production, water-treating agents, pigment dispersants, adhesives, binders, and films.
Effects and Advantages of the Invention
The present invention can provide a production process for a terminal-end-stabilized glyoxylic acid (salt)-based polymer, which process enables to reduce the amount of the polymerization solvent, as recovered or removed after the end of the polymerization (before the start of the hydrolysis) or after the end of the hydrolysis, without lowering the production efficiency.
Hereinafter, the present invention is more specifically illustrated by the following examples of some preferred embodiments in comparison with comparative examples not according to the invention. However, the invention is not limited to these examples.

Production process for glyoxylic acid (salt)-based polymer


A semiconductor device without erroneous operation and deterioration of characteristics in a transistor even when an impurity region is formed in self-alignment by ion implantation using a gate electrode as a mask, and a method of manufacturing thereof are disclosed. This semiconductor device includes a gate electrode formed of a polycrystal silicon layer 4b having the crystal orientation of the crystal grains arranged in a definite orientation. By implanting ions at a predetermined angle with respect to the crystallographic axis of the crystal grains of the polycrystal silicon layer 4b in forming a p.sup.+ impurity region 5 by ion implantation using the gate electrode as a mask, the channeling phenomenon where ions pass through the gate electrode is prevented. Therefore, generation of erroneous operation and deterioration of characteristics in a transistor are prevented in forming an impurity region in self-alignment by ion implantation using the gate electrode as a mask.

1. Field of the Invention
The present invention relates to semiconductor devices, and more particularly, to a semiconductor device having an impurity region formed by ion implantation with a gate electrode as a mask, and a method of manufacturing thereof.
2. Description of the Background Art
An MOS transistor is well known as one type of a semiconductor device. FIG. 7 is a sectional view of a conventional P channel MOS transistor comprising a gate electrode. Referring to FIG. 7, a P channel MOS transistor comprises an N type silicon substrate 11, element isolation oxide films 12 formed on N type silicon substrate 11 with a predetermined distance therebetween for element isolation, p.sup.+ impurity regions 15 with a predetermined distance therebetween formed between element isolation oxide film 12, and a polycrystal silicon layer 14 forming a gate electrode provided between p.sup.+ impurity regions 15 with a gate oxide film 13 thereunder. A conventional P channel MOS transistor has a gate electrode formed by polycrystal silicon layer 14.
FIG. 8 is an enlarged sectional view of the gate electrode of FIG. 7 for explaining the crystal structure. Referring to FIG. 8, polycrystal silicon layer 14 forming a conventional gate electrode has the crystal orientation of the crystal grains arranged in a plurality of plane orientations. That is to say, polycrystal silicon layer 14 has crystal grains of (110) plane orientation and crystal grains of (111) plane orientation in the example of FIG. 8. Polycrystal silicon layer 14 is doped with phosphorus.
FIGS. 9A-9D are sectional views of a conventional P channel MOS transistor for explaining the manufacturing process thereof. Referring to FIG. 9A, element isolation oxide films 12 are formed on an N type silicon substrate 11 with a predetermined distance therebetween for element isolation. A gate oxide film 13 is formed on N type silicon substrate 11 and element isolation oxide films 12. Referring to FIG. 9B, a polycrystal silicon layer 14 having phosphorus doped is formed on gate oxide film 13. Polycrystal silicon layer 14 serves as a gate electrode. This polycrystal silicon layer 14 is formed of crystal grains having different plane orientations, as described above. Referring to FIG. 9C, gate oxide film 13 and polycrystal silicon layer 14 are patterned by etching using a resist pattern (not shown). Thus, a gate electrode having the structure of the present embodiment is obtained. Referring to FIG. 9D, B.sup.+ ions 16 are implanted to form p.sup.+ impurity regions 15, using polycrystal 0 silicon layer 14 as a mask. A conventional P channel MOS transistor is formed according to the above described manufacturing process. Polycrystal silicon layer 14 eventually is formed of crystal grains having two crystal orientations of (110) and (111) plane orientations, as described above.
In a conventional P channel MOS transistor, p.sup.+ impurity regions 15 are formed in self-alignment by implanting B.sup.+ ions using polycrystal silicon layer 14 which becomes a gate electrode as a mask.
Because the above described polycrystal silicon layer 14 is formed of crystal grains having crystal orientations different from each other, there was a problem that B.sup.+ ions pass through polycrystal silicon layer 14 if the crystal orientation is identical to the implantation angle of the ions. This problem is called a channeling phenomenon. The implantation of B.sup.+ ions right beneath the gate electrode due to channeling phenomenon induces problems that will be explained hereinafter. The channel region between p.sup.+ impurity regions 15 serving as the source/drain is likely to become conductive (channel leak) which is adverse to the proper operation. The generation of channel leak induces a problem that leak current and erroneous operation are increased of the entire semiconductor device. There was also a problem that the threshold voltage rises concerning the transistor characteristic of the P channel MOS transistor.
A conventional P channel MOS transistor had a difficulty in preventing effectively generation of erroneous operation and deterioration of the characteristic of a transistor, in the case where an impurity region is formed in self-alignment by ion implantation using a gate electrode as a mask.

Semiconductor device having a gate electrode of polycrystal layer and a method of manufacturing thereof


Secret information is encoded/distributed into distributed information according to access structure, a random number sequence corresponding to number of pieces into which the secret information is distributed is generated by randomly selecting polynomial coefficients, the coefficients are encoded/distributed into random number information according to access structure, a hash function whose hash values correspond to the random number sequence is generated, keys for which the hash function applies are selected so as to individually set data for checking whether restored secret information is being manipulated as number of pieces of check data corresponding to number of pieces into which the secret information is distributed, the distributed information is read, the secret information is restored; the random number information is read, the random number sequence is restored, the check data is read, and the restored secret information is judged as not being manipulated when the read check data satisfies the hash function.

When keeping secret information such as a secret key used for encryption, there are the threat of "losing and damaging" it and the threat of having it "stolen". For the former case, it is effective to generate a backup copy of the secret information. However, making the copy may increase a risk of facing the latter threat. As one of information security techniques for overcoming such issue, there is a secret distribution method depicted in Non-Patent Documents 1 and 2.
The secret distribution method is characterized to generate a plurality of pieces of distributing information acquired by distributing secret information, keep those separately, and generate it possible to uniquely restore the original secret information by gathering a preset number of pieces of distributed information among the kept distributed information. However, it is impossible to restore the secret information by gathering the distributed information other than those pieces. Hereinafter, in this Description, the number of pieces of distributed information is defined as "n" pieces, and each of n-pieces of distributed information is identified by using identifiers of 1 to n.
With the secret distribution method, a set of distributed information with which the secret information can be restored can be defined with "Γ" that is a set group of the distributed information of an access structure. The access structure "Γ" is a set group that has, as elements thereof, a set of identifiers of the minimum number of pieces of distributed information with which the secret information can be restored. With the secret distribution method having the access structure "Γ", "a set w of the distributed information is capable of restoring the secret information" means that there is "V" that satisfies a following Expression 1 for a set W of the identifiers of the distributed information corresponding to the set w. Further, the set W of the identifiers of the distributed information having a character satisfying Expression 1 is defined as an access set of "Γ".VεΓ and VW  [Expression 1]
As the secret distribution method, there is a method called a (k, n) threshold scheme. The (k, n) threshold scheme is a secret distribution method which distributes secret information into n-pieces of distributed information, and uses k (n>K) pieces of distributed information among the n-pieces of distributed information to restore the secret information. Note that "k" in the (k, n) threshold scheme corresponds to V of Expression 1 described above. An access structure "Γ" used in the (k, n) threshold scheme is defined by a set group shown in Expression 2. The access structure "Γ" has two characters, i.e., "secret information cannot be restored at all with less than k-pieces of distributed information among the n-pieces of distributed information" and "secret information can be restored uniquely from the k-pieces or more pieces of distributed information". Hereinafter, issues when restoring the secret information with the secret distribution method will be investigated.Γ={V|V{1,2, - - - ,n} and number of elements of V is k}  [Expression 2]
When restoring the secret information, it is necessary to collect the required number of pieces of distributed information for restoring the secret information from a plurality of recording modules which keep the individual distributed information. In this case, it is not perfectly sure that the requested side of the distributed information gives the distributed values, specifically, the distributed information kept in the recording modules, to the restorer without manipulation. That is, there may be a case where the distributed information in the recording modules is handed over to the restorer after being manipulated.
The "manipulation" herein means not only a case where an administrator to which the distributed information is given manipulates the distributed information intentionally but also a case where the distributed information is manipulated against the intention of the administrator of the distributed information. As examples of the case where the distributed information is manipulated against the intention of the administrator, there are cases where the distributed information is manipulated because of a fault generated in a device which stores the distributed information to the recording modules, cases where the distributed information is manipulated due to an operation error of the administrator, etc.
When the secret information is restored by using the manipulated distributed information, values of the restored secret information may, become different from values of the original secret information. Thus, as the secret distribution method, desired is a method which can detect with a high probability that there are manipulated values contained in the distributed information used for restoration.
Further, a means for selecting the distributed information varies depending on the operation forms. Therefore, it is desired to have a high detection rate of the manipulated values regardless of the types of probability distributions upon which the distributed information is selected.
As the techniques for overcoming such issues, the techniques depicted in Non-Patent Documents 3 to 7 are known.
Non-Patent Document 3 discloses a (k, n) threshold scheme which can detect a cheating of altering merely (k−1) pieces of distributed information by referring to (n−1) pieces of distributed information with a probability of (1−ε) regardless of the types of the probability distribution upon which the secret information is selected. With the method depicted in Non-Patent Document 3, assuming that the secret information is a set containing s-pieces of elements, the distributed information is a set containing the number of elements shown with Expression 3. Note that "n" and "k" correspond to "k" and "n" of the (k, n) threshold scheme.Number of elements=((s−1)(k−1)/ε+k)2  [Expression 3]
Non-Patent Document 4 discloses a (k, n) threshold scheme which can detect cheating of manipulating merely (k−1) pieces of distributed information by referring to (k−1) pieces of distributed information with a probability of (1−ε) on condition that the secret information is selected based upon a uniform probability distribution. With the method depicted in Non-Patent Document 4, assuming that the secret information is a set containing s-pieces of elements, the distributed information is a set containing the number of elements shown with Expression 4. Note that "k" corresponds to "k" of the (k, n) threshold scheme.Number of elements=(1+(s−1)/ε)  [Expression 4]
Non-Patent Document 5 discloses a (n, n) threshold scheme which can detect cheating of manipulating merely (k−1) pieces of distributed information by referring to (k−1) pieces of distributed information with a probability of (1ε) regardless of the types of the probability distribution upon which the secret information is selected. With the method depicted in Non-Patent Document 5, assuming that the secret information is a set containing s-pieces of elements, the distributed information is a set containing the number of elements shown with Expression 5. The (n, n) threshold scheme is a secret distribution method which distributes secret information into n-pieces of distributed information, and uses the n-pieces of distributed information to restore the secret information. Note that "n" of the (n, n) threshold scheme of the secret distribution method corresponds to "k" mentioned above.Number of elements=s/ε2  [Expression 5]
Non-Patent Document 6 discloses a (k, n) threshold scheme which can detect cheating of manipulating merely (k−1) pieces of distributed information by referring to (n−1) pieces of distributed information with a probability of (1ε) regardless of the types of the probability distribution upon which the secret information is selected. With the method depicted in Non-Patent Document 6, when the secret information is a set containing s-pieces of elements and s satisfies s≦1/ε, the distributed information is a set containing the number of elements shown with Expression 6. Note that "k" corresponds to "k" of the (k, n) threshold scheme.Number of elements=s2/ε  [Expression 6]
Non-Patent Document 7 discloses a (k, n) threshold scheme which can detect cheating of manipulating merely (k−1) pieces of distributed information by referring to (n−1) pieces of distributed information with a probability of (1ε) regardless of the types of the probability distribution upon which the secret information is selected. With the method depicted in Non-Patent Document 7, when the secret information is a set containing s-pieces of elements and s satisfies s≦1/ε, the distributed information is a set containing the number of elements shown with Expression 7. Note that "k" corresponds to "k" of the (k, n) threshold scheme.Number of elements=s×(log(s))k+1/ε  [Expression 7]
Patent Document 1 related to the secret distribution method as described above discloses a structure which allocates distributed information generated by a (k+t, n+t) method for each of n-pieces of administrator devices. Patent Document 2 discloses a structure which acquires a plurality of optimum allocated maps for a general access structure by integer programming.
Patent Document 3 discloses a data protection method and the like which store generated distributed information by further encrypting it with a public key, restore the distributed information with a secret key, and then restore secret information that is the original data. Patent Document 4 discloses a distributed information restoring system and the like with which a distributed information managing device conceals and saves distributed information with random numbers according to a request from an information utilization device that saves the random numbers.    Patent Document 1: Japanese Unexamined Patent Publication 2002-217891    Patent Document 2: Japanese Unexamined Patent Publication 2004-336577    Patent Document 3: Japanese Unexamined Patent Publication 2008-097591    Patent Document 4: Japanese Unexamined Patent Publication 2008-250931    Non-Patent Document 1: Adi Shamir, "How to share a secret", Comm. ACM, 22(11), 612-613 (1979)    Non-Patent Document 2: J. Benaloh and J. Leichter, Generalized secret sharing and monotone functions, in "Advances in Cryptology - - - CRYPTO '88", S. Goldwasser, ed., Lecture Notes in Computer Science 403, pages 27-35, 1989    Non-Patent Document 3: Martin Tompa, Heather Woll, "How to Share a Secret with Cheaters", Journal of Cryptology, vol. 1, pages 133-138, 1988    Non-Patent Document 4: Wakaha Ogata, Kaoru Kurosawa, Douglas R. Stinson, "Optimum Secret Sharing Scheme Secure Against Cheating", SIAM Journal on Discrete Mathematics, vol. 20, no 1, pages 79-95, 2006    Non-Patent Document 5: Satoshi Obana and Toshinori Araki, "Almost Optimum Secret Sharing Schemes Secure Against Cheating for Arbitrary Secret Distribution", Advances in Cryptology - - - Asiacrypt 2006, Lecture Notes in Computer Science 4284, pp. 364-379, 2006    Non-Patent Document 6: Toshinori Araki, "Efficient (k, n) Threshold Secret Sharing Schemes Secure Agianst Cheating from n−1 Cheaters", Proceedings of ACISP 2007, Lecture Notes in Computer Science 4586, pp. 133-142, 2007    Non-Patent Document 7: Satoshi Obana, "General Making Method of Safe Secret Sharing Scheme against n−1 Cheaters", Symposium on Cryptography and Information in 2008, SCIS 2008 Publication, 2008
There are following issues generated with Non-Patent Documents 1 to 7 described above. That is, there may be a case where several people managing distributed information conspire together to improve secret information that is to be restored by a single restorer. Specifically, secret information is distributed into n-pieces of distributed information by making (k−1)-degree polynomial, those pieces of distributed information are managed by being distributed to two or more administrators to be managed, and the distributed information is collected from k−1 people to restore the secret information. To improve the secret information restored by a single restorer (referred to as a proper user hereinafter), the conspirers partially restore the (k−1)-degree polynomial based on the distributed information held by themselves, manipulate the distributed information held by themselves, rewrite the manipulated distributed information to a (k−1)-degree polynomial containing the distributed information held by the proper user from the original (k−1)-degree polynomial, and give the manipulated distributed information to the proper user.
When the proper user restores the secret information by having the distributed information included in the distributed information held by the user oneself, the secret information different from the original secret information is restored since the (k−1)-degree polynomial used for restoration is rewritten.
However, there is no means for detecting whether or not the restored secret information is being manipulated taken in the techniques of Non-Patent Documents 1 to 7 described above, so that the restore (proper user) who does not intend cheating cannot restore the secret information.
Further, there is also no technical means taken in the techniques disclosed in Patent Document 1 to 4 for overcoming the issues generated in Non-Patent Documents 1 to 7.
It is an object of the present invention to provide a secret information distribution system, a secret information distributing method and a program thereof for detecting whether or not the restored secret information is being manipulated when those who hold distributed secret information conspire to manipulate the distributed information.

Secret information distribution system, secret information distribution method and program


A method and apparatus for bypassing a boundary-scan cell during functional operation of an electronic component provides a component output signal (such as a data signal) to a boundary-scan bypass circuit during normal functional operation of the electronic component. The component output signal is multiplexed in the bypass circuit with the test result signal that occurs during boundary-scan testing. During functional operation of the electronic component, the component output signal is selected and provided to an output latch that is clocked by a transition of the clock signal of the electronic component. By bypassing the component output signal around the boundary-scan cell during normal operation, the traversing of the multiplexer by the component output signal after the transition of the clock signal of the component is avoided, thereby reducing off-chip delay.

The present invention relates to test logic included in an integrated circuit for testing the interconnections between integrated circuits once they have been assembled onto a printed circuit board or other substrate, for testing the integrated circuit itself, and for observing or modifying circuit activity during the component's normal operation. In particular, the present invention relates to improvements increasing operating speed of boundary-scan architecture.
A product is typically constructed from a collection of components that are mounted on a printed circuit board, each of these components having a plurality of pins that connect the component to the circuit board. An integrated circuit used in a board-level design will normally have an established test methodology for that component. Components could be tested on an automatic test equipment system or by using a self-test procedure embedded in the design.
Once the component has been assembled onto the printed circuit board, access to the normal connections of the assembled circuit is limited. Providing the test data to the component and retrieving test data from the component is therefore difficult after assembly. Normally, an in-circuit test is needed in order to test the component in the same manner as it is tested in isolation.
For allowing test facilities built into the component to be used or to apply pre-existing patterns, test data needs to be conveyed to or from the boundaries of the individual component so that it can be tested as if it was free standing. An accepted method for conveying test data is with a boundary-scan cell coupled with a test access bus.
The conventional boundary-scan technique uses a shift-register stage contained in a boundary-scan cell that is located adjacent each component pin so that signals at the component boundaries can be controlled and observed using scan testing principles. The boundary-scan technique is well-known and is the subject of IEEE Std 1149.1-1990, relating to the IEEE Standard Test Access Port and Boundary-Scan Architecture, Institute of Electrical and Electronics Enginers, (May 21, 1990).
In order to test the component, test instructions and associated test data are fed into the component by the boundary-scan cell and, subsequently, the results of the execution of such instructions are read out. All of the information (instructions, test data, and test results) is communicated in a serial format. Typically, the sequence of operations is controlled by a bus master, which can be either automatic test equipment (ATE) or a component that interfaces to a higher-level test bus as a part of a complete system maintenance architecture. Control is achieved through signals applied to the test mode select and test clock inputs of the various components connected to the bus master.
Following execution of the test instruction, the results of the test are examined by shifting the data out of the component using the boundary-scan cell. The boundary-scan cells are connected directly to the connection pins of the individual components so that the test signals into and out of the component pass through the boundary-scan cell.
In conventional designs, the boundary-scan cell also receives the normal functional output data of the component when the cell is connected to an output pin of the component and the component is in the normal operation mode. At this time, the boundary-scan cell is not in the test mode and merely passes through the output data from the component. Since both functional data and test data pass through the boundary-scan cell, conventional boundary-scan cell design includes a multiplexer that selects between: (1) the functional data that is output by the component in normal operation; and (2) the test data output by the component or shifted in by another boundary-scan cell when the component and the boundary-scan cell are in a test mode.
In the normal functional operation of the component, the last functional register stage of the component outputs the data at the rising edge of the component clock signal. The functional data signal must then traverse the multiplexer of the boundary-scan cell before being outputted as the output signal of the component. In normal functional operation of the component, the boundary-scan cell therefore adds an off-chip delay that is equivalent to the multiplexer delay. This added delay can make it impossible for a design implemented in a specific technology to meet signal arrival times, unless the boundary-scan circuitry is completely removed and replaced with other, more costly test methods.

Boundary-scan bypass circuit for integrated circuit electronic component and circuit boards incorporating such circuits and components

International Business Machines Corporation


Basic elements of a modular printer system may comprise a rectangular open frame with receptacles for a printer module and computerized terminal module, and with an external configuration for receiving modular components such as a carrying handle, a support foot, an auxiliary terminal module mounting bracket and an AC adaptor module. Respective different paper tray modules may be selectively secured to the open frame to form a bottom closure and to provide a repository for appropriate circuit boards and an on-board battery if needed, as well as containing an appropriate supply of paper for the printer (e.g. 50 sheets or 200 sheets). Respective terminal adaptor modules may secure different generations of computerized terminals in the frame for data transfer to the printer. A terminal module may utilize a spring-urged retainer for retaining a hand-held computerized terminal therewith. Respective printer modules may adapt different printer models to the frame, and each such printer module may be reversible in the frame to accommodate different applications, e.g. as a portable unit, and as a van-mounted unit with in-board, out-board and/or remote mounting of terminal modules.

This invention is particularly concerned with printer devices such as are utilized in connection with product delivery e.g. to retail stores. In a field known as route accounting, a computerized terminal maintains price and quantity information concerning various items to be delivered at a series of stores, and a printer unit is utilized to produce a printed record for each customer. The printer may be carried into each store with the terminal, or the printer may be part of the fixed equipment within a delivery vehicle.
In a typical route accounting system, a portable modular printer device may comprise a briefcase containing the printer unit. Preferably such portable systems have a receptacle for plug-in coupling of a computerized terminal.
In the past, systems providing an eighty column printing capacity have utilized portable configurations representing relatively high cost beyond the cost of the basic printer unit, and adding very substantially to the basic weight of the printer.
It is conceived that it would be highly beneficial to create a portable printer system requiring only minimal additions in terms of cost and weight over that of the basic printer. It would be ideal if a modular standardized construction could be applicable also to non-portable printer systems and capable of readily receiving computerized terminals of different configuration.