Patents by Inventor Hiroshi Nakatsuka

Hiroshi Nakatsuka 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).

  • Publication number: 20050057324
    Abstract: A thin film bulk acoustic resonator includes a piezoelectric film, and a pair of electrodes between which the piezoelectric film is interposed. The piezoelectric film includes an outer region extending outwards from at least a portion of the periphery of a resonator portion composed of the pair of electrodes and the piezoelectric film. The outer region includes, in at least a portion thereof, an acoustic damping region for damping acoustic waves.
    Type: Application
    Filed: September 8, 2004
    Publication date: March 17, 2005
    Inventors: Keiji Onishi, Hiroyuki Nakamura, Hiroshi Nakatsuka, Takehiko Yamakawa
  • Publication number: 20050057117
    Abstract: A piezoelectric resonator of the present invention is structured such that on a substrate 5 having a cavity 4 formed therein, a lower electrode 3, a piezoelectric body 1, a spurious component control layer 16, and an upper electrode 2 are formed in this order from bottom up. The spurious component control layer 16 is a layer for controlling a spurious frequency, and composed of, for example, a metallic material, a dielectric material, or a piezo electric material. By additionally providing the spurious component control layer 16, it is made possible to cause variation of the spurious frequency due to unwanted variation to become greater than variation in resonance frequency of the main resonance of the piezoelectric resonator. Thus, it is possible to realize a piezoelectric resonator having an admittance frequency response where no spurious component occurs between resonance frequency fr and antiresonance frequency fa.
    Type: Application
    Filed: September 13, 2004
    Publication date: March 17, 2005
    Inventors: Hiroshi Nakatsuka, Keiji Onishi, Hiroyuki Nakamura, Takehiko Yamakawa
  • Publication number: 20040256960
    Abstract: A compact and high-power piezoelectric transformer is realized by using higher order longitudinal extensional mode vibrations and increasing an effective electromechanical coupling factor by a primary electrode which consists of plural electrodes.
    Type: Application
    Filed: July 20, 2004
    Publication date: December 23, 2004
    Inventors: Katsu Takeda, Hiroshi Nakatsuka, Takeshi Yamaguchi, Kojiro Okuyama, Katsunori Moritoki
  • Publication number: 20040232806
    Abstract: A piezoelectric transformer includes a rectangular plate which is mainly made of piezoelectric material and in which a dimension in a longitudinal direction is larger than that in a width direction and a thickness direction is orthogonal to the longitudinal direction and the width direction. A low-impedance portion acting as one of a driving portion and a generator portion and a high-impedance portion acting as the other of the driving portion and the generator portion are provided in the rectangular plate so as to be arranged in the width direction such that the piezoelectric transformer is driven in a width-extensional vibration mode.
    Type: Application
    Filed: May 12, 2004
    Publication date: November 25, 2004
    Inventors: Hiroshi Nakatsuka, Katsu Takeda
  • Publication number: 20040227434
    Abstract: A piezoelectric transformer includes a piezoelectric ceramic disc having one face and the other face opposite to each other in a thickness direction. A pair of low-impedance portions acting as one of a driving portion and a generator portion are disposed in the piezoelectric ceramic disc symmetrically with respect to a central axis of the piezoelectric ceramic disc, while a pair of high-impedance portions acting as the other of the driving portion and the generator portion are disposed in the piezoelectric ceramic disc symmetrically with respect to the central axis so as to be electrically separated from the low-impedance portions such that the piezoelectric transformer is driven in a radial extensional vibration mode of the piezoelectric ceramic disc.
    Type: Application
    Filed: May 11, 2004
    Publication date: November 18, 2004
    Inventors: Katsu Takeda, Hiroshi Nakatsuka
  • Patent number: 6812623
    Abstract: A compact and high-power piezoelectric transformer is realized by using higher order longitudinal extensional mode vibrations and increasing an effective electromechanical coupling factor by a primary electrode which consists of plural electrodes.
    Type: Grant
    Filed: September 23, 2002
    Date of Patent: November 2, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katsu Takeda, Hiroshi Nakatsuka, Takeshi Yamaguchi, Kojiro Okuyama, Katsunori Moritoki
  • Patent number: 6794796
    Abstract: The piezoelectric transformer of the present invention has a piezoelectric element 109 mainly formed of a piezoelectric material, primary electrodes 101U and 101D which are formed on the piezoelectric element 109 and to which a voltage is applied, a secondary electrode 102 which is formed on the piezoelectric element 109 and from which a voltage higher than the voltage applied to the primary electrode is output, and a sensor electrode 103 which is formed on the piezoelectric element 109 and from which a voltage lower than the output voltage of the secondary electrode is output.
    Type: Grant
    Filed: January 9, 2003
    Date of Patent: September 21, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Nakatsuka, Katsunori Moritoki, Toshiyuki Asahi, Kojiro Okuyama, Osamu Kawasaki
  • Publication number: 20040104884
    Abstract: There is provided a method for driving a piezoelectric transformer in which a driving efficiency and the reliability in terms of withstand power and distortion can be enhanced by suppressing a higher order vibration mode exited by a harmonic component other than a driving frequency included in a driving signal of the piezoelectric transformer without using an inductive element. The driving signal applied to a primary side electrode of the piezoelectric transformer is a signal in a rectangular waveform having a time period &dgr;T in which a level is a maximum potential (2V) or a minimum potential (0), obtained by multiplying a period T of the driving signal by a predetermined time ratio &dgr;. The time ratio &dgr; is set to be smaller than 0.5 and so as to minimize a sum of ratios of amplitudes of respective higher order vibration modes with respect to an amplitude of a vibration mode exciting the piezoelectric transformer.
    Type: Application
    Filed: November 21, 2003
    Publication date: June 3, 2004
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katsu Takeda, Hiroshi Nakatsuka
  • Patent number: 6737816
    Abstract: The piezoelectric transformer of the present invention has a piezoelectric element 109 mainly formed of a piezoelectric material, primary electrodes 101U and 101D which are formed on the piezoelectric element 109 and to which a voltage is applied, a secondary electrode 102 which is formed on the piezoelectric element 109 and from which a voltage higher than the voltage applied to the primary electrode is output, and a sensor electrode 103 which is formed on the piezoelectric element 109 and from which a voltage lower than the output voltage of the secondary electrode is output.
    Type: Grant
    Filed: May 11, 2001
    Date of Patent: May 18, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Nakatsuka, Katsunori Moritoki, Toshiyuki Asahi, Kojiro Okuyama, Osamu Kawasaki
  • Patent number: 6720705
    Abstract: The invention provides a method of driving a piezoelectric transformer and a power source apparatus using the same. For a circuit for driving a piezoelectric transformer which steps up a voltage input from a primary electrode by a piezoelectric effect to output the stepped up voltage from a secondary electrode, the gradient (linear differential value) of a step-up ratio at the piezoelectric transformer is detected, and the detected gradient is used to control the driving frequency for the piezoelectric transformer so that the driving frequency approaches to the resonant frequency of the piezoelectric transformer.
    Type: Grant
    Filed: August 16, 2001
    Date of Patent: April 13, 2004
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Nakatsuka, Takeshi Yamaguchi, Katsu Takeda, Katsunori Moritoki, Kojiro Okuyama
  • Publication number: 20030234762
    Abstract: The present invention provides a light emission control device that can drive a plurality of cold cathode fluorescent tubes independently only by connecting a plurality of piezoelectric transformers to only one piezoelectric inverter circuit. A first phase control portion that outputs a signal for changing a phase of the third and the fourth driving control signals with respect to a phase of the first and the second driving control signals to the second driving portion, and a second phase control portion that outputs a signal for changing a phase of the fifth and the sixth driving control signals with respect to a phase of the first and the second driving control signals to the third driving portion are provided in the piezoelectric inverter circuit. Thus, the phase difference of the driving control signals is controlled, so that the output powers to the plurality of cold cathode fluorescent tubes are controlled.
    Type: Application
    Filed: June 5, 2003
    Publication date: December 25, 2003
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Nakatsuka, Katsu Takeda
  • Publication number: 20030137222
    Abstract: A compact and high-power piezoelectric transformer is realized by using higher order longitudinal extensional mode vibrations and increasing an effective electromechanical coupling factor by a primary electrode which consists of plural electrodes.
    Type: Application
    Filed: September 23, 2002
    Publication date: July 24, 2003
    Inventors: Katsu Takeda, Hiroshi Nakatsuka, Takeshi Yamaguchi, Kojiro Okuyama, Katsunori Moritoki
  • Patent number: 6583534
    Abstract: The piezoelectric transformer of the present invention has a piezoelectric element 109 mainly formed of a piezoelectric material, primary electrodes 101U and 101D which are formed on the piezoelectric element 109 and to which a voltage is applied, a secondary electrode 102 which is formed on the piezoelectric element 109 and from which a voltage higher than the voltage applied to the primary electrode is output, and a sensor electrode 103 which is formed on the piezoelectric element 109 and from which a voltage lower than the output voltage of the secondary electrode is output.
    Type: Grant
    Filed: June 5, 2000
    Date of Patent: June 24, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Nakatsuka, Katsunori Moritoki, Toshiyuki Asahi, Kojiro Okuyama, Osamu Kawasaki
  • Publication number: 20030102776
    Abstract: A driving circuit for a piezoelectric transformer is provided, which ensures lighting of all the cold-cathode tubes connected to the piezoelectric transformer, and reduces the difference in brightness between the cathode tubes during steady lighting, thereby enhancing reliability and performance. A plurality of cold-cathode tubes connected to a secondary side of the piezoelectric transformer, and a cold-cathode tube output detector circuit connected in series to a plurality of cold-cathode tubes, for detecting an output state of the respective cold-cathode tubes are provided, and the driving of the piezoelectric transformer is controlled based on a detection signal from the cold-cathode tube output detector circuit. Because of this, the piezoelectric transformer performs the same operation as that with respect to one cold-cathode tube.
    Type: Application
    Filed: November 27, 2002
    Publication date: June 5, 2003
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katsu Takeda, Hiroshi Nakatsuka, Katsunori Moritoki
  • Publication number: 20030102780
    Abstract: The piezoelectric transformer of the present invention has a piezoelectric element 109 mainly formed of a piezoelectric material, primary electrodes 101U and 101D which are formed on the piezoelectric element 109 and to which a voltage is applied, a secondary electrode 102 which is formed on the piezoelectric element 109 and from which a voltage higher than the voltage applied to the primary electrode is output, and a sensor electrode 103 which is formed on the piezoelectric element 109 and from which a voltage lower than the output voltage of the secondary electrode is output.
    Type: Application
    Filed: January 9, 2003
    Publication date: June 5, 2003
    Inventors: Hiroshi Nakatsuka, Katsunori Moritoki, Toshiyuki Asahi, Kojiro Okuyama, Osamu Kawasaki
  • Publication number: 20030098861
    Abstract: A driving circuit for a piezoelectric transformer is provided, which is capable of driving a piezoelectric transformer at a high efficiency and with low distortion, and being miniaturized. At the commencement of lighting a cold-cathode fluorescent tube, a digital controller fixes frequencies of first and second control signals VC1 and VC2 at a predetermined frequency and controls the phase difference therebetween so that an output power of the piezoelectric transformer becomes from substantially zero to a predetermined output power. After lighting of the cold-cathode fluorescent tube, the digital controller controls the phase difference between the first and second control signals VC1 and VC2 so that current detecting data CD substantially is matched with reference data RD.
    Type: Application
    Filed: November 14, 2002
    Publication date: May 29, 2003
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Nakatsuka, Katsu Takeda, Takashi Ishikawa, Katsunori Moritoki
  • Patent number: 6566821
    Abstract: The present invention relates to a drive device for one or more series-connected cold cathode fluorescent lamps having an electrical terminal at each end. The drive device has a piezoelectric transformer for converting by means of the piezoelectric effect a primary ac input applied to primary electrodes to a secondary ac output, which is removed from secondary electrodes; a drive arrangement for applying the primary ac input to the primary electrodes; and a brightness control circuit for controlling brightness. The drive device is configured so that the end electrical terminals of the cold cathode fluorescent lamp can be connected between the two secondary electrodes. The brightness control circuit detects the phase difference between the secondary ac output and the primary ac input. When the detected phase difference is greater than a specified phase difference, the drive arrangement reduces the power of the primary ac input applied to the primary electrodes.
    Type: Grant
    Filed: December 21, 2001
    Date of Patent: May 20, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Nakatsuka, Takeshi Yamaguchi, Katsu Takeda, Katsunori Moritoki
  • Patent number: 6509700
    Abstract: The invention provides an apparatus and a method for driving a cathode discharge tube such that the discharge starting voltage can be lowered by simple construction. At the start of lighting a cathode discharge tube light, AC voltage applied to the cathode discharge tube is raised at a speed slower than a rise speed of the cathode discharge tube. By lighting the cathode discharge tube in this way, the lighting start voltage can be reduced.
    Type: Grant
    Filed: November 16, 2001
    Date of Patent: January 21, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Nakatsuka, Takeshi Yamaguchi, Katsu Takeda, Katsunori Moritoki, Kojiro Okuyama
  • Patent number: 6509671
    Abstract: A driving method and a driving circuit for a piezoelectric transformer are capable of driving the piezoelectric transformer with high driving efficiency independently of an impedance change of a load such as a cold cathode tube by corresponding to the characteristic variance of the piezoelectric transformer, thereby also suppressing mechanical damage to be imposed on the piezoelectric transformer itself even if the load changes abruptly. The piezoelectric transformer is driven with a predetermined first frequency, and a power supply for a load connected to the secondary side of the piezoelectric transformer is started, and when an impedance of a load changes and reaches a predetermined impedance during the power supply, the driving frequency of the piezoelectric transformer is changed without a sweep from the first frequency to a predetermined second frequency.
    Type: Grant
    Filed: May 31, 2001
    Date of Patent: January 21, 2003
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Katsu Takeda, Hiroshi Nakatsuka, Katsunori Moritoki, Takeshi Yamaguchi
  • Publication number: 20020190611
    Abstract: A low loss, small scale piezoelectric transformer, suited for a cold cathode tube load, and having a high effective coupling factor, is provided using a piezoelectric plate having a single polarization direction. Controlling the dimensions of the third electrode portion 15a constituting the high impedance portion makes it possible easily to adjust the capacitance of the electrostatic capacitor formed between the first electrode portion 12 and the third electrode portion in accordance with the load. Also, the second electrode portion 13 and the fourth electrode portion 15b constituting the low impedance portion are substantially equal in area and the third electrode portion and the fourth electrode portion are formed in one piece, so that energy propagation efficiency can be increased.
    Type: Application
    Filed: June 14, 2002
    Publication date: December 19, 2002
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Nakatsuka, Katsu Takeda, Katsunori Moritoki, Hiroshi Fukushima, Yusuke Adachi