Patents by Inventor Keiji Akamatsu

Keiji Akamatsu 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: 20090009436
    Abstract: Provided are a PDP device and a drive method thereof which restrict the generation of an erroneous discharge in the all-cell reset period and to restrict the appearance of flickers in the areas with low grayscale levels even if some areas have a lower firing voltage than the other areas due to variation of a property in the panel surfaces or due to a long-term driving, or even if the voltage applied to the address electrode is increased with the pursuit of high definition. The pulse Pul.3 is applied to address electrodes Dat at timing t0 prior to timing t1 when the potential of the scan electrodes Scn is increased to Vq(V). In this drive method, voltage Vx(V) is applied to address electrodes Dat so that there is no potential difference between the scan electrodes Scn and the sustain electrodes Sus at timing t0 when discharge Dis.3 is generated. Accordingly, the discharge Dis.
    Type: Application
    Filed: March 17, 2006
    Publication date: January 8, 2009
    Inventors: Keiji Akamatsu, Kenji Ogawa, Mitsuo Ueda
  • Patent number: 7274116
    Abstract: A bypass control section (6) maintains a bypass switch (5) in the ON state during the period when a battery voltage (Vi) is higher than the output voltage (Vo) to an external load (L). Upon falling of the output voltage (Vo) at a desired voltage (ET), a converter control section (4) starts switching control at once, and a step-up chopper (3) promptly starts boost operation. The bypass control section (6) maintains the bypass switch (5) in the ON state from the start of the boost operation of the step-up chopper (3) until the match between the battery voltage (Vi) and the output voltage (Vo).
    Type: Grant
    Filed: August 2, 2004
    Date of Patent: September 25, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Manabu Inoue, Takuya Ishii, Keiji Akamatsu, Masaaki Kuranuki, Hiroki Akashi
  • Publication number: 20060006850
    Abstract: A bypass control section (6) maintains a bypass switch (5) in the ON state during the period when a battery voltage (Vi) is higher than the output voltage (Vo) to an external load (L). Upon falling of the output voltage (Vo) at a desired voltage (ET), a converter control section (4) starts switching control at once, and a step-up chopper (3) promptly starts boost operation. The bypass control section (6) maintains the bypass switch (5) in the ON state from the start of the boost operation of the step-up chopper (3) until the match between the battery voltage (Vi) and the output voltage (Vo).
    Type: Application
    Filed: August 2, 2004
    Publication date: January 12, 2006
    Inventors: Manabu Inoue, Takuya Ishii, Keiji Akamatsu, Masaaki Kuranuki, Hiroki Akashi
  • Patent number: 4064777
    Abstract: A circuit in an electronic keyboard musical instrument for preferentially selecting the highest and lowest tones from among the tones in chords produced by keys on the keyboard which have been struck. The circuit has a set of series connected resistors having equal values, the number of resistors in the set corresponding to the number of tones from which the highest and lowest tones are to be selected. An end resistor is connected between each end of the set of resistors and a reference voltage level. A plurality of transistors corresponding to the number of resistors each has the emitter thereof connected to the set of resistors between the corresponding resistor and the resistor corresponding to the next adjacent transistor, and has the collector thereof adapted to receive a corresponding tone signal. A keyswitch is connected to the base of each transistor and to a bias source.
    Type: Grant
    Filed: August 26, 1976
    Date of Patent: December 27, 1977
    Assignee: Roland Corporation
    Inventor: Keiji Akamatsu