Patents by Inventor Hirofumi Kawashima
Hirofumi Kawashima has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6010572Abstract: A dip coating method, in which a cylindrical member is dipped in a coating solution in a coating solution tank and the coating solution is coated on an outer peripheral surface of the cylindrical member by the cylindrical member being raised, includes the steps of: making the coating solution always overflow from the coating solution tank; dipping the cylindrical member into the coating solution through an opening portion of a cover which is provided above a surface of the coating solution in the coating solution tank, and which has the opening portion through which the cylindrical member can pass, and which has a plurality of plates which are disposed at intervals in a vertical direction; and raising the cylindrical member.Type: GrantFiled: July 28, 1997Date of Patent: January 4, 2000Assignee: Fuji Xerox Co., Ltd.Inventors: Yasuo Furusawa, Toshiaki Takahashi, Shigeto Hashiba, Kiyoshi Hashimoto, Hirofumi Kawashima
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Patent number: 5469010Abstract: A method of adjusting a frequency-to-temperature coefficient of an NS-GT cut quartz resonator comprises providing a coupling resonator having a first order temperature coefficient .alpha..sub.+. A normalized frequency .delta. of the coupled vibrational modes is then calculated according to the relationship .alpha..sub.+ =m.delta.+n, where m and n are constants. The normalized frequency .delta. is then adjusted according to the relationship .alpha..sub.+ =m.delta.+n to set the first order temperature coefficient to substantially zero.Type: GrantFiled: March 3, 1994Date of Patent: November 21, 1995Assignee: Seiko Electronic Components Ltd.Inventor: Hirofumi Kawashima
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Patent number: 5334900Abstract: A torsional quartz crystal resonator has a specific cut type resulting in improved frequency temperature behavior. The cut type is defined by rotating a Z plate quartz crystal around an x-axis at an angle .phi. in the range of 0.degree. through 30.degree. and by further rotating the plate around a z'-axis at another angle .theta. in the range of -20.degree. through -10.degree. or +10.degree. through +20.degree.. The resonator has a thickness z.sub.0 and a width x.sub.0 determined such that a thickness-to-width ratio Rzx=z.sub.0 /x.sub.0 is set within the range of 0.6 through 1.1 to make the first order temperature coefficient substantially zero in combination with the optimum angles .phi. and .theta.. Excitation electrodes are disposed on major faces of the resonator normal to the z' axis, and a connecting electrode is disposed on a side face of the resonator to reduce the series resistance R.sub.1.Type: GrantFiled: August 23, 1993Date of Patent: August 2, 1994Assignee: Seiko Electronic Components Ltd.Inventor: Hirofumi Kawashima
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Patent number: 5311096Abstract: A width-extensional mode quartz crystal resonator formed by etching from a quartz crystal plate which is cut along a plane defined in the O-xyz coordinate system of the quartz crystal lattice by rotating the original Z plane around the x axis by a rotation angle in the range of 23.degree.-28.degree.. The quartz crystal resonator has a thickness-to-width ratio R.sub.zx in the range of 0.45-0.65. A pair of exciting electrodes are disposed on the resonator along opposed side faces perpendicular to the widthwise direction. The width-extensional mode quartz crystal resonator may be etched from a quartz crystal plate to provide a small sized resonator. A width-extensional mode vibrational portion is supported at its lengthwise sides by a pair of first bridge portions extending from a first frame portion. A pair of second bridge portions extend from a second frame portion and support the first frame at central portions of its lengthwise sides.Type: GrantFiled: January 17, 1992Date of Patent: May 10, 1994Assignee: Seiko Electronic Components Ltd.Inventor: Hirofumi Kawashima
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Patent number: 5218260Abstract: A longitudinal quartz crystal resonator has at least two vibrating arms arranged in parallel to each other to undergo a longitudinal vibration. The vibrating arms are connected together at both ends thereof by connecting sections. A pair of bridge sections extend from central parts of respective ones of the outermost vibrating arms and are connected to flexional sections. The bridge sections are supported through surrounding frame sections by a bottom mount section. The flexional sections are connected to the frame sections so as to form surrounding openings. By such construction, an equivalent inductance and a series resistance are reduced in the longitudinal quartz crystal resonator so as to eliminate vibrating energy loss.Type: GrantFiled: January 22, 1992Date of Patent: June 8, 1993Assignee: Seiko Electronic Components Ltd.Inventor: Hirofumi Kawashima
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Patent number: 5059853Abstract: A longitudinal quartz crystal resonator which creates an extremely small amount of vibrational leakage. Quartz is a highly stable material physically and chemically. A so-called quartz crystal resonator formed of quartz therefore has a low series resistance and a high Q-value. Such excellent characteristics are, however, obtained on the condition that the quartz crystal resonator is designed so as to produce a less leakage of vibration. Energy of a vibrational portion is trapped within itself by contriving and improving a configuration of a supporting portion of the longitudinal quartz crystal resonator which is incorporated with the vibrational portion and the supporting portion by an etching method.Type: GrantFiled: July 13, 1990Date of Patent: October 22, 1991Assignee: Seiko Electric Components Ltd.Inventor: Hirofumi Kawashima
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Patent number: 5001383Abstract: A small longitudinal quartz crystal resonator has an intermediate oscillating frequency from 500 KHz to 4.2 MHz, a reduced energy loss of vibration, a small equivalent series resistance and zero temperature coefficient. The resonator has a longitudinal vibrational portion of rod-like shape connected at its central portion to a pair of supporting portions through each bridge portion. Each supporting portion is shaped to avoid suppression of oscillation of the vibrational portion. The vibrational and supporting portions are formed integrally by etching method. Driving electrodes are formed on etched faces of the vibrational portion perpendicular to X-axis. The resonator is composed of a quartz crystal plate cut out by cut angle of -2.degree. to +4.degree. around X-axis with respect to a Z-plate. The vibrational portion may have tapered end portions to increase the oscillating frequency in high frequency range up to 4.2 MHz.Type: GrantFiled: September 7, 1989Date of Patent: March 19, 1991Assignee: Seiko Electronic Components Ltd.Inventor: Hirofumi Kawashima
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Patent number: 4900971Abstract: A face shear mode quartz crystal resonator having a vibrational portion and supporting portions incorporated therein by an etching method. A flexural portion of the supporting portion is connected with a central portion of a side of the vibrational portion. The width W and length L of the flexural portion connected with the vibrational portion are designed so as to meet "W.ltoreq.0.67L". The supporting portions are provided at the edges in the z'-axis direction of the vibrational portion which is substantially square and fixedly supported via both distal end portions of the supporting portions, and each side of the vibrational portion is from 0.72 mm to 2.02 mm.Type: GrantFiled: March 7, 1989Date of Patent: February 13, 1990Assignee: Seiko Electronic Components Ltd.Inventor: Hirofumi Kawashima
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Patent number: 4633124Abstract: A mounting is provided for a GT-cut, coupled mode piezoelectric resonator. The mount includes pedestals with recesses. Portions of the resonator are mounted in the recesses.Type: GrantFiled: March 15, 1983Date of Patent: December 30, 1986Assignee: Kabushiki Kaisha Daini SeikoshaInventor: Hirofumi Kawashima
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Patent number: 4525646Abstract: A lithium tantalate (LiTaO.sub.3) vibrator comprises a lithium tantalate crystal vibratable in the flexural mode and having an electro-mechanical coupling factor within the range 0.04 to 0.10. The crystal may have a tuning fork shape cut from a Z-plate turned an angle of 48.degree. to 55.degree. around the X-axis.Type: GrantFiled: October 24, 1979Date of Patent: June 25, 1985Assignee: Seiko Instruments & Electronics, Ltd.Inventor: Hirofumi Kawashima
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Patent number: 4484382Abstract: Each resonant frequency of a coupling resonator is measured at a plurality of each different temperatures. From these values the first order temperature coefficient .alpha. is calculated. According to the value of .alpha., it is accurately adjusted and finally the resonant frequency of a fundamental vibration is also adjusted to a nominal frequency.Type: GrantFiled: March 30, 1982Date of Patent: November 27, 1984Assignee: Seiko Instruments & Electronics Ltd.Inventor: Hirofumi Kawashima
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Patent number: 4472655Abstract: A tuning fork flexural quartz resonator is cut out from a Z plate rotated at 25.degree.-165.degree. around the X-axis as the rotary axis. The resonator with an excellent frequency sensitivity of about -100 ppm/.degree.C. is obtained when the cut angle .theta. is 120.degree..Type: GrantFiled: March 25, 1983Date of Patent: September 18, 1984Assignee: Kabushiki Kaisha Daini SeikoshaInventor: Hirofumi Kawashima
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Patent number: 4355257Abstract: A thickness shear type piezoelectric vibrator comprises a quartz crystal plate of uniform thickness having a rectangular vibrating portion and integral rectangular supporting portions of less width extending from opposite ends of the vibrating portion. Electrodes of conducting material have elongated rectangular active portions on obverse and reverse surfaces of the vibrating portions of the plate. The electrode on the obverse surface of the plate has an integral lead portion extending along the obverse surface of only one of the supporting portions. The electrode on the reverse surface of the plate has an integral lead portion extending along the reverse surface of the other only of the supporting portions so that an electric field is applied by the electrodes only to the vibrating portion of the plate and not to the supporting portions.Type: GrantFiled: July 14, 1980Date of Patent: October 19, 1982Assignee: Kabushiki Kaisha Daini SeikoshaInventors: Hirofumi Kawashima, Akira Watanabe, Yasunori Ebihara
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Patent number: 4234812Abstract: A thickness-width shear quartz crystal vibrator, having each vibrating mode (p, q, r) respectively being (1, 1, 1), in which "p" is the number of crests of a sine wave form of polarization directed along its electrical axis, "q" is the number of crests of a cosine waveform of polarization directed along its thickness and "r" is the number of crests of cosine waveform of polarization directed along its width perpendicular to the said electrical axis. The vibrator is cut out from a Y-plate of quartz crystal at the angle between 34 to 36 degrees turned around the X-axis thereof and is provided with plural opposite electrodes on the vertical surface or the surface parallel to the y-axis thereof. Therefore, the said quartz crystal vibrator has a low equivalent impedance and also has an excellent frequency-temperature characteristic.Type: GrantFiled: July 28, 1978Date of Patent: November 18, 1980Assignee: Kabushiki Kaisha Daini SeikoshaInventor: Hirofumi Kawashima
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Patent number: 4178566Abstract: An oscillator circuit including a flexural quartz crystal vibrator of the tuning fork type having an electromechanical coupling factor within the range of 2.5% to 3.5%. The vibrator is comprised of a quartz crystal element including a base portion and a pair of vibratable legs extending therefrom, and a pair of electrodes disposed on the quartz element for receiving alternating electrical signals of opposite polarity for effecting flexural vibration of the legs in response to the electrical signals. The quartz element is defined by a cutting angle within the range of zytw (0.degree.-10.degree.)/(10.degree.-30.degree.).Type: GrantFiled: July 6, 1978Date of Patent: December 11, 1979Assignee: Kabushiki Kaisha Daini SeikoshaInventor: Hirofumi Kawashima
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Patent number: 4178527Abstract: A quartz crystal tuning fork vibrator comprises a monolithic quartz crystal vibrator having a tuning fork shape with a plurality of vibratable tines. A set of electrodes are adhered to opposite surfaces of the tuning fork vibrator and are arranged in such a manner that when suitable alternating voltage is applied thereto, the tines undergo flexural vibration in their fundamental or resonance mode. The electrodes on each tine surface are preferably arranged in groups of four with the center two being applied with voltage of one polarity when the outer two are applied with voltage of the other polarity thereby establishing electric fields within the tines at the outside portions thereof while no electric field is established at the center portion of the tines. All of the flexural strain is thus confined to the outside portions of the tines thereby lowering the amplitude of vibration of the tine ends to the order of 5.mu.-10.mu..Type: GrantFiled: December 1, 1977Date of Patent: December 11, 1979Assignee: Kabushiki Kaisha Daini SeikoshaInventor: Hirofumi Kawashima
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Patent number: 4112323Abstract: A piezoelectric flexural vibrator comprises a circular or polygonal disc of piezoelectric crystal such as quartz, lithium tantalate or lithium niobate which is formed by chemical etching and is supported around its periphery with electrodes on opposite faces comprising a pair of electrodes each of which is divided into two portions of which one is on one face of the disc and the other is on the opposite face of the disc. By reason of its small size -- 25 to 150 microns thick and less than 10mm across -- and its good frequency-temperature characteristics, the vibrator is suitable for use in wristwatches.Type: GrantFiled: January 28, 1977Date of Patent: September 5, 1978Assignee: Kabushiki Kaisha Daini SeikoshaInventor: Hirofumi Kawashima